SIXTH EDITION
NSCP C101·10
nNATIONA j
I I, ! I
I
TRUCTURAL CODE OF THE PHILIPPINES
VOLUME I BUILDINGS, TOWERS AND OTHER VERTICAL STRUCTURES SIXTH EDITION
Association of Stmctural Engineers of thc Philippincs Suite 7 I3, Future Point Plaza Condominium 1 112 I'anay Avenue, Quezon City, Philippines 1100 Tel. No ; (+632) 410-0483 F"x No.: (+632 ) 411-S606 Enlail: i~~l!."!.!ili!.l...I.;Yf.gJ]]illL~~Jl!.! Webs ite: http: //www.aseponline.org Nat!Oni'll Structural Code of U'le Philippines 6!il Edition Volume 1
NSCP C101-10
NATIONAL S~rRUCTURAL
CODE OF THE PHILIPPINES 2010
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I
VOLUME I BUILDINGS, TOWERS AND OTHER VERTICAL STRUCTURES SIXTH EDITION
I
Association of Structural Engineers of th e Philippines
NATIONAL STR UcrURAL CODE OF THE PHILIPPINES (NSCP) CIOI-IO Volume I Buildings, Towers and Other Vert ica l Structures Sixth Edition, 2010, First Plinting Copyright @ 20 I0, The Association of Structural Engineers of the Philippines, Inc. (ASEP) All rights reserved. Thi s publicat ion or any part thereof must no! be reproduced in any fom1 wilhoullhe written pcmlission of Ihe Associat ion Slructu ral Engineers of the Philippines, Inc. (ASEP).
ISSN No.: 2094-5477 PUBLISHER Association of Structural Engi neers of the Philippines, Inc. (ASEP) Suite 713 Future POilU Plaza Condominium 112 Panay A venu e, Quezon City, 1100 Philippines
Telephone Nos.
(+632) 410-0483 (+632) 411-8606
Facsimile No. E-mail address
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\Vebsite
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The Association of Structural Engineers of the Phili ppines, Inc . (ASEP) is a professiona l Association found ed in August
1961 to represent the structural engineering communi ty nationwide. This document is published in keeping wilh the association's objectives; Maintenance of high ethi cal and profess ional standards in the practice of structuraJ engineering; Advancement of structural engineering knowledge; Promot ion of good public and private clientele relationship; and Fellowship among structural engineers, and professional relations wit h other allied technical and scienlific organi zat ions.
Print His tory First Edition, 1972 Second Edition, 1981 Third Edit ion, 1987 Fourth Edi tio n, 1992 Fifth Edition, 2001 Sixth Edition. 20 J 0
National Structural Code of the Philipp ines 6" Edit ion Votume 1
FOREWORD For the protection of public life and propeny, the design of structures and the preparation of structural plans for their construction have to be controlled and regulated. For almos t four decades now, this control has been exercised in this countly by the National Structural Code of the Philippines with the initial publication by the Association of Structural Engineers of the Philippines (ASEP) of the National Structural Code for Buildings. The c urrent publication of the 6'" Edition of NSCP CIOI - 10 for buildings, towers and other vertical structures is the affinnation of the mandate of the ASEP to continuously update the National Structural Code of the Philippines with the latest technological developments. While attaining a legal status in its use as a referral code of the National Building Code, NSCP CIOI-1O is a publication of high technical value in matters of structural concerns.
The NSCP CIOI-IO is not only complete ly new in its technical substance but also in its format. It has been a product of a sustained effon of ASEP spanning nine years and the fruition of this endeavor has finally come to reality during my incumbency. It is therefore with a deep feeling of gratitude and pride that I commend the members of the ASEP Board, the Codes and Standards Committee and the Publicity and Publications Committee for their accomplishments.
May 2010.
AD~S'F.ASEP
Presiderll Association of Structural Engineers of the Philippines. 2009-2010
Association of Structural Engineers of the Philippines
PREFACE TO THE NSCP SIXTH EDITION 1.
Introduction ASEP recognizes the need for an up-to-date structural code addressing the design and instalbtion of building stmclUral systems through requirements emphasizing performance. The new National Stl1Jctural Code of the Philippines (NSCP) is designed 10 meet these needs through various model codes/regulations, generally from the United S((I(CS, to safeguard the public health and safety nationwide.
This updated StI1lc(ural Code establishes minimum requirements for building structural systems using prescriptive and pcrforrnance-bascd provisiolls. It is founded 011 broad-based principles [hat make possible the usc of new materials (ind new building designs. Also, this code rencets the latest seismic design practice ror ea rthq uake rcsis!allt structures. 2.
Changes and Developments In ilS drive 10 upgrade and updale Ihe NSCP, Ihe ASEP Codes and Siandards Commillee inilially wanled 10 adopi the larest editions of American code counterparts. However, for cases where available local data is limited to suppon the upgrade, then some provisions and procedures of the NSCP 5 th edition were retained. This NSCP 6th edi tion is based on the follow ing international codes and references: a.
Uniform Building Code UBC·1997 (adopled for Earlhquake Loads)
u.
Imernational Building Code IBC·2009 (referenced)
c.
American SocielY of Civil Engineers ASCE7·0S (adopted for Wind Loads)
d.
American Concrete Institute ACI318·08M
c.
American Institute for Steel Construction AISC·05 with Supplementary Seismic Provisions
f.
American Iron and Sleelinslitute AISI S 100-2007
g.
Reinforced Masonry Engineering Handbook America
h.
Concrete Masonry H andbook, 6th Edition
Signifi cant rev is io ns are summari z.ed as follows: a.
Chap ter I - Genera l Requirement s. The rollowing changes arc madc in this code: a. J
Section 103 - Classification of Buildings School buildings of more than one storey, hospitals and designated evacuation ce nters are added under the essential facilities category.
a.2
Section 104 - Design Requirements Deflection of any structural member under the serviceabili ty requ iremen t is deleted. For concrete and Sir:l,'.1 materials see Chapter 4 and 5 respecti vely; new requiremenls are added 10 the design review section.
a.3
Section 105 - Post ing and InslrUme nlati on The provision of installed recording accelerograph is adjusted.
National Structural Code of the Philippines 6'" Edition Volume 1
b.
Chapter 2 - Minimum Design Loads. The changes made in this code are as follows: b.i
Section 203 - Combination of Loads
The load factor val ues on wind 100lds (Ire loads. b.2
adjll~ted
together with the inclusion of rOlin
Section 205 - Live Loads Additional loads arc in corporated in the table for minimulll uniform and concentrated loads.
b.3
Sec ti on 207 - Wind Load s Wind load provisio ns, which were previously based on ASCE7-9S, are updated by lhe introduct ion of the 'Wind Directionality Facto r, KJ , based on ASCE7-0S. The ANSI ErAITIA-222·G is also referenced for wind loads on antennas. Equations [or the gust effect facLOrs for both rigid and flexible structures are introduced. These include the gust effect factor for antennas, tran smission and latticed towers, poles/posts, masts and transmission Jines based on ASCE Manual of Practice NO.74 (Guide lines for Electrical Transmission Line Stru ctural Loading). New rormu las are also introd uced for the natural freq uency and damping rat io.
h.4
Sec ti on 208 - Earthquake Loads Basi ca lly. Lhere are no major changes on the earthquake provisions due 10 the 110navailabiJi'lY of Phivolcs-issued spectral acceleration maps for all areas in the Philippines. However, ASCE/SEI7-05 is recognized as an alternativ e procedure in the determination of the earthquake loads.
b.S
Section 210 and Section 2i 1- Environmemal Loads New sections on rai n loads and nood loads are added.
c.
Chapter 3: Specifications ror Excavations and Geomatcrials. The revisions made in this updated code arc ,IS rollows: c.1
Provisions ptrtaining to the conduct and interpretation of found
c.2
The secti on on root ings is amended to in corporate provisions for differcntial selli c meni , design loads and vibratory loads;
c.3
The section on pile foundations is amendcd to incorporate new provisions on splicing of
concrete piles; and
cA
d.
Th e section on special foundations, slope stabilization and matcrials of constructio n are added.
Chapte r 4: Structural Concretc. The revi sions made in th is upda ted code arc as follows: d. 1
Sectioll 40 I . Genera l Requirements: Design requ iremcnts for carthquakc-rcsistam x!ructurcs arc updated based on ACI 3IS-0SM which mentions the "Seism;c Design Cillcgorks (SDCs)" or ASCEISEI 7-0's. However, ill the absence of Phi voles-issued spectral acceleration maps for
Association of Structural Engincms of the Philippines
d.2
Section 403 - Materials: New requirements for headed shear stud reinforcement, headed deformed bars, and stainless steel bars are given wi~h appropriate references to ASTM standards;
d.3
Section 404 - Durability Requirement: Exposure categories and classes, requirements or concrete by exposure class are adopted to replace the many tables of durability requirements in Section 404, making it easief to clearly specify the intended application;
<1.4
Section 405 - Concrete Quality, Mixing, and Placing: The use of three JOO 111m x 200 cylinders is adopted as equivalent to the use of two 150 I11Ill x 300 mm cylinders for determining concrete cornpressive strength. Due to concern that material properties may change with time, a 12-month limit is set on historical data used (0 qualify mixture proportions and flexural test performance criteria arc added to qualify the use of steel fiber - reinforced concrete as a replacement for minimum shear reinforcement; 111m
d.5
Section 407 - Details of Reinforcement: To avoid the misconception that there is no minus tolerance on cover values given in the code, "minimum cover" is replaced with "specified cover" throughout Section 407; Class B lap splices are now required for structural integrity reinforcement; continuous top and bottom structural integrity reinforcement are required to pass through the column core; and requirements for transverse reinforcement confining structural integrity reinforcement in perimeter beams are clarified;
d.6
Section 408 - Analysis and Design - General Considerations: Provisions are modified \0 allow redistribution of positive moments; and a simple modeling procedure for evaluation of lateral displacements is added;
d.7
Section 409 ~ Strength and Serviceability Requirements: Strength reduction factors for compression-controlled sections (other structural members) is reduced from 0.70 to 0.65, and shear and torsion for shear walls and frames in Seismic Zone 4 is reduced from 0.85 to 0.75, bearing on concrete (except for post-tensioning anchorage zones) is reduced from 0.70 to 0.65. Strength reduction factors for strut-and-tie models, Ilexural sections in prctensioncd members, afC also added;
d.8
Section 4JO - Flexure and Axial Loads: The section on slenderness effects is reorganized to recognize computer analysis techniques as the primary method of evaluating secondorder effects;
d.9
Section 411 - Shear and Torsion: Code requirements are added to permit the lise of headed stud assemblies as shear reinforcement for slabs and footings. The nominal shear strength is permitted to be larger for headed stud assemblies than for other forms of slab and footing shear reinforcement; more stringent limits arc placed on the depths of beams that are exempted from the requiremellt for minimulll shear reinforcement; a new limit 011 the depth of ho!low core units for which minimum shear reinforcement could be waived is established; steel fiber-reinforced concrete· is added as an alternative to minimulll shear reinforcement; and the upper limit on shear friction strength is significantly increased for monolithically placed concrete and COllcrete placed against intentionally roughened concrete;
th
Nation8i Structural Code of the Philippines G Edition Volume 1
cl.lO
Section 412 - Development and Splices of Reinforcement: Provisions are added for the development length of headed deformed bars; splice length when splicing bars with different sizes is addressed; and a coating factor of 1.0 for galvanized reinforcement is added;
d.II
d.12
Section 4 J 3 - Two-Way Slab Systems: Dimension limits are added for the use of shear caps; and alternative corner reinforcement arrangement is added for two-way slabs supPol1ed [).Y edge beams or walls; Section 414 ..- Walls: Design provisions for slender wall panels are modified to be more consistent with the methods used in design practice;
d.13
Section 418 - Prestressed Concrete:
The allowable concrete compression stress
immediately after prestress transfer is increased; and requirements for structural integrity steel in two-way unbonded post-tensioned slab systems are modified; d.14
Section 4.20 - Strength Evaluation of Existing Structures: Load factors for determining the required test load are modified to reflect typical modern load combinations;
d.IS
Section 421 - Earthquake-Resistant Structures: This section prescnts thc requiremcnts for Seismic Resistant Design from ASCEISEI 7-05, but instead of using the Scismic Design Categories of ASCEfSEI 7-05, the equivalent Seismic Zones as per UBC 1997 are specified. Also, new design requirements are added for slIch seismic zones; ncw detailing option is added for diagonally reinforced coupling beams; design yield strength for confincment reinforcement is raised to 690 MPa to help reduce congestion; and boundary clement confinement requirements is relaxed;
d.16
Section 423 - Anchoring to Concrete: Use of reinforcement In the vicinity of anchors and ductility requirements for anchors in seismic zones are clarified.
d.17
Section 425 - Altcrnative Provisions for Reinforced and Prestressed Concrete Flexural and Compression Mcmbcrs: Revisions in Appendix B of ACI 3J8-08M is adopted;
e.
d.18
Section 426 - Alternative Load and Strength Reduction Factors: Revisions in Appendix C of ACI 318-08M is adopted, and
d.19
Section 427 - Strut-and-tie Modcls: entirety.
Appendix A of ACI 3 I 8-08M is adopted in ils
Chapter 5: Structural Steel. The revisions made in this updated code arc as follows: c. J
Adopted is an integrated treatment of the Allowable Stress Design (ASD) and the Load and Rcsistance Factor Design (L,RFD) such that the earlier Specification that treated only the ASD method is retained;
c.2
In lieu of the previolls mcthod of analysis, a new method (Direct Analysis Method) is adoptcd; and
eJ
The cold formed steel design for building systems and structural members are included.
Thc chapler on slcel design from NSCP 200 I which covered Allowable Working Stress Design (ASD) is fully updated to address usage, advances in the statc of knowledge, and changes in design practice. f.
Chapter 6: Wood 1"1
The provisions in this chapter arc refined to iocorporate local practices and corrections in [he previous vcrsion of lhe code (NSCP 2(01). Referrals arc made to the NSCP 2010
J\ssocialion of Structural Engineers of t!~e Philippines
Vol. III on Housing for relevant provisions concerning single-family dwellings / low-cost housing; f.2
Tables from the previous version of NSCP 2001 includiog the Table containing specie design information are amended to incorporate the latest updated information/ list of wood species as provided by the Forest Products Research and Development Institute (FPRDI);
g.
1'.3
A provision that limit the use of wood shear walls and diaphragms is added; and
fA
A section for Machine Graded Lumber (MGL) is included.
Chapter 7: Masonry g.1
The provisions in this chapter are refined to include local practices and corrections from the previous versioo of the code (NSCP 2001); referrals are made to the NSCP 2010 Vol. III on Housing for relevant provisions concerning single-family dwellings / low-cost housing;
g.2
Recycled aggregates are defined and provided;
g.3
A section for Seismic Design is added; and
g.4
Additional sections each for Masonry Fireplaces and Masonry Chimneys arc included.
This publication of the 6th Edition is a collective effort of the ASEP Board of Directors from 2007 to 2010, from ASEP's past presideots Christopher P. T. Tamayo (2007-2008) and Wilfreda S. Lopez (2008-2009) and the ASEP Codes and Standards Committee whose cooperation made this publication. In addition, the ASEP Codes and Standards Committee is indebted to Philippine Institute of Volcanology and Seismology (Phivolcs) and to DiL Renato V. Solidum, Ph. D. for his unselfish contribution especially on Chapters I and 2 of this codc. Likewise, our thanks to all ASEP mcmbers and other users of the NSCP who have suggested improvements, identified errors and recommended items for inclusion and omissions. Their suggestions have been carefully considered. ASr.~P also acknowledges the contribution of the industry partners, companies and individuals, who continue suppon ASEP's numerous undertakings.
3.
to
Disclaimer
The reader is cautioned that professional judgment must be exercised when data or recommendations afe applied. The information presented has been prepared in accordance with recognized engineering principles anel is for genera! information only. This information should not be used or relied upon for any specific application without competent profcssioll,li examination and verification of its accuracy, suitability and applicability by a registered engineer. Anyone .making usc of this information assumes all liabilities arising from sllch usc.
National Structural Code of the Philippines 6
111
Edition Volume 1
ADAM C ABINALES,
m:"';:~ '·.ASf.I'
WILFREDO S. LOPEZ,
MCM . .. .AS.:I'
AS£!' Presidenl, 2009-20/0
ASEt' Presidl!llf, 2008-2009
ANTHONY VLADIMIJ{ C. PIMENTEL, "",,"'
CHRISTOPHER 1'. T. TAMA YO, ,.• "."
ASEP lIice-Presidenl, 2009-2010 (/Ild
ASr:;P Pr('sit/{!III, 2007·2008
M(I"ogill[: Director, Cod(!.\" (111(/ Standard.l· Commillcc
EM ILO M. MORALES, ~lsn:• •·.ASI:.' Ch(lirman. Codes (IIu/ SUlllti(/rdJ COII/lllitlt'e
ROMEO A. ESTANEnO, '·b.n .. ...... St:l· At/viser, Codes (llld SI
CODES AND STANDARDS COMMITTEE GENERAL REQUIREMENTS
LOADS AND ACTIONS
CARLOS M, VILLAHAZA , ,'..'."" CltaimuJII VIRGILIO C. COLUMNA, ~!I:"~~ t·....:m·
CARLOS M. VILLAHAZA, ' ''''' Chaimum VIRGILIO C. COJ..UMNA, .' ,..:.....·.AM:'· Co-CJwimwl/
Co-Clwimwil
RONALDO S. ISON, I".\ s .:r RON\VALDO EMMANUEL R AQUINO, Work Grollp M embl'rs
~I SC:L~L\ SEr
BENITO M. PA CHECO, ''''-I' •• I·.AS'':I' CESAR I', PAllA LAN, ,.• <'" RONALDO S.ISON, F.ASEl' HONWALDO EMMANUEL R. AQUlNO, """""" nUTn n. MAUILANGAN, M sn:'~I""SH Work Group M embers
EXCAVATIONS AND GEOMA TERIALS MARK ZAH C O,
STRUCTURAL CONCRETE JORGE P. GENOTA,
I'I.R
!"-\SH
Choir/llO/l
Chairl/l(/ll
ROY ANTHONY LUNA,
~IS(· I .
WILFREDO S. LOPEZ,
Co- Clwirll1l11l
Lm:1'
Co-Chair'lIIall
JONATHAN R. DUN GCA ,,,.,,. MARK K. MORALES, ".". DANIEL C. PECKLEV JR, . ~ ... BUlAN B. TAN, ~I.~t"l: Work Group M"",b('l's
ANDHES WINSTON C. ORETA, rh. II. RAMIL H. CRISOLO, .,,~"" JUANITO C. CUNANAN,
Mc\SEI"
".,u'
Ill-AS N. ESPINOSA, ".""" BERNA RI)O A. LEJANO, !·hJI.• M.ASI'.'· Work Gmllp Members
AHNEL R. AGUEL,
~I."'SH·
ResO/lrce Perso/l
ROMEO A. ESTANERO, Acll';.\'(!r
Association o f Structural EnDinfl8fS of ltle Philippine:;
n.. IL ....ASt:'·
;'" \'
,\ NTI/ONY VLADIMIR C. PIMENTEL,
..
'A'"
CHRISTOPHER P.T. TAMAYO, w ..~ CJw irman
CilllimllUl
GILBERT n. MACBUTAY, ".,,,,, F R EDERICK FRA NC IS M. SISON, ","".
ALAN C. AllAN,
F.ASf.P
Co·Chainnan
RICO J. CADANGON, r~J) . ! fltrHl ACHILLES L. LUARDO, ""''' ROY T. ROQUE, ~u s~')'
C,,·Chairmen
ALLAN DERDY A. ALFILER, )u s.:r ALLAN n. BENOCSUDAN, MA'''' EDGA RDO S. CRUZ~ M.AStl' JONATHA N C. SEVILLA, .","'"
Work Group Members
Work Group Members
MAsONRY
ASEP SECRETARIAT
C HRISTO PHER P.T. TAMAYO, ,."". Chairman
ALAN C. AllAN ,
AlLYN C. ANONICAL Administrative Officer
r","SEI'
'Co·Clwim/(U/
MA Y A. JA C INTO
LEOPOLDO R. BUENA VENTURA, JR., M A.""· JAY EMERSON V. LIM, MA.m'
Account Officer
CERELINE C. LUCASIA JUNE B. CATS
Work Group Members
Administrative Staff
1h
National Structural Code of th e PhilipPines 6 Edition Volum e 1
ASSOCIA TION OF STRUCTURAL ENGINEERS OF THE PHILIPPINES COMMITTEE ON CODES AND STANDARDS (2007-2010)
Letter of' Acknowledgemen t and Appreciation ' 1 wish to convey my deepest appreciation and Ihanks for Ihe invaluable service rendered by the various volunteer chairpersons and members of Ihe commiltees in making Ihis major NSCP 2010 6'" Edilion a reality. The time, money and personal sacrifices rendered by the various Commillee Chairpersons are sincerely and deeply appreciated. Withou t these unselfish contributi ons, this monumental task would not have been at all possible. My sincerest thanks are also offered to our sponsors and benefaclors who have responded 10 our call by supporting the NSCP Ihrough their advertise ments which are very valuable in reducing the cost of prinling 10 make the NSCP more afford able and mOre widespread in di stribution . As we launch the NSCP 20 10 6'" Edition, we stay committed towards disseminating the important fealures and new revisions to the Code by conducting regional and city seminars as a service to Ihe civil engineering profession and also to help Ihe slructural engineering profession keep abreasl with the state of praclice and state of Ihe art in slrucluml engineering. As we have gone to this initial launch, we encourage the end-users 10 give us their inva luable comments towards making the NSCP a living code and more receptive 10 Ihe needs of Filipino engineers. Special thanks also go to the ASEP Presidenl and Ihe Board of Directors and the ASEP Secretariat for the valuable support and assistance given in the preparation o f the revised NSCP 2010 6'h Edilion.
. MORALES MSCE. F.i\SEP. F..PICE. F.ASCE Chairm 11 Commillee 011 Codes and Standardsjor NSCP 2010 6,10 Edition
Association of Stru ctural Engineers of tile Philippines
ASSOCIATION OF STRUCTURAL ENGINEERS OF THE PHILIPPINES OFFICERS AND DIRECTORS (2009-2010)
OFFICERS: ADAM C. ABINALES, MEng., F.ASEl' Presidelll ANTHONY VLADIMIR C. PIMENTEL, F.ASEI' Vice Presidellt MIRIAM LUSICA·TAMA YO, MSCF" F.ASEl' Secretary VIRGILIO B. COLUMNA, MEng.,F.ASEl' Treasurer
DIRECTORS: ANTONIO A. AVILA, M.ASEP DANILO A. DOMINGO, M.ASEl' RONAL DO S. ISON, F.ASEl' FREDERICK FRANCIS M. SISON, M.ASEI' PEDRO M. TOLENTINO, JR., M.ASEl' VINCI NICHOLAS R. VILLASENOR, F.ASEI' WILFREDO S. LOPEZ, MeM, F.ASEl' Im mediate Past President
COLLEGE OF FELLOWS: ROMEO A. ESTANERO, I'h .D., FASE!' Challcel/or JORGE 1'. GENOTA, F.ASEI' Scribe CARLOS M. VILLARAZA, F.ASEl' Burse,.
111
National Structural Code of the Pt1i1ippines 6 Edition Vall!me 1
ASSOCIATION OF STRUCTURAL ENGINEERS OF THE PHILIPPINES OFFICERS AND DIRECTORS (2008-2009)
OFFICERS: WILFREDO S. LOPEZ,
MeM, F.ASEI'
President
ADAM C. ABINALES,
MEng., F.ASEP
Vice President
VIRGILIO C. COLUMNA,
MEng.,F.ASEP
Secretary
VINCI NICOLAS R. VILLASENOR,
F.ASEP
Treasurer
DIRECTORS: DANILO A. DOMINGO, M.ASEP RONALDO S. ISON, F.ASEP JORGE P. GENOTA, LASEP FREDERICK FRANCIS M. SISON, M.ASEI' ANTHONY VLADIMIR C. PIMENTEL, F.ASEP PEDRO M. TOLENTINO, JR., M.ASEI' CHRISTOPHERI'. T. TAMAYO,
F.ASEP
Immediate Past President
COLLEGE OF FELLOWS: ROMEO A. ESTANERO,
Ph.D., F.ASEP
Chancelior
JORGE P. GENOTA,
F.ASEP
Scribe
Association of Structural Engineers of the Philippines
ASSOCIATION OF STRUCTURAL ENGINEERS OF THE PHILIPPINES OFFICERS AND DIRECTORS (2007-2008)
O!FFICERS: CHRlSTOPHER 1'. T. TAMA YO,
F.ASEl'
President
WlLFREDO S. LOPEZ, MCM,F.ASEP Vice President
VIRGlLIO C. COLUMNA,
MEng.,F.ASEP
Secretary
ELMER P. FRANCISCO, M.ASEP Treasurer
DIRECTORS: ADAM C. AlBIN ALES, MEng., F.ASEP FERDINANJ[) A. BRIONES, M.ASEP DANILO A.. DOMINGO, ~I.ASEP RONALIDO S. ISON, F.ASEP BERNARDO A. LEJANO, !'h.D., M.ASEP PEDRO M. TOLENTINO, JR., M.ASEI' JORGE P. GENOTA,
F. ASEP
Imm ediate Pas{ Presidelll
COLLEGE OF FELLOWS: ROMEO A. ESTANERO,
Ph . D. , F.ASE!'
Chancellor
JORGE P. GENOTA,
F.ASE!'
Scribe
1h
National Structural Code of the Philippin es 6 Edition Volume 1
Department of Public Works and Highways
Association of Structural Engilwers of ttle Philif}plnes
NSCP C101-10
Chapter 1
GENERAL REQUIREMENTS NATIONAL STRUCTURAL CODE OF THE PHILIPPINES VOLUME I BUILDINGS, TOWERS AND OTHER VERTICAL STRUCTURES SIXTH EDITION
Association of Structural Engineers of the Philippines Suite 713, Future Point Plaza Condominium 1 112 Panay Avenue, Quezon City, Philippines II 00 Tel. No: (+632) 410-0483 Fax No.: (+632) 411-8606 Email: asepon JincCmgll1
National Struclura l Code of the Philippines 6'" Edillon Volume 1
,
Association of Structural Engineers of the Philippines
CHAPTER 1 - General Requirements
1-1
Table of Contents CHAPTER I· GENERAL REQUIREMENTS ...................................................................................................................... 3 SECTION 101 . TITLE, PURPOSE AND SCOPE ................................................... ............................................................. 3 101.1 Title ...... .... . 101.2 Purpose ...... .... .... ..... ........ ... .... ........ ... ..... .. . 10 J.3 Scope .... .... ... .... . '" ....... ........ ........... ..... .. . 101.4 Ahemative Systems._ .. ... ............. .. .. _...................................... ..... .
....... 3 ...... ... 3 ........ . 3 .
..... .. 3
SECTION 102 . DEFINITIONS ............................................................................................................................................... 3 SECTION 103 . CLASSIFICA T10N OF STRUCTURES .................................................................................................... 5 103.1 Nature of Occupancy ................... ..................... ... ................. ........ ..... ............. ....... ........................... .. ........... .... ........... 5
SECTION 104 • DESIGN REQUIREMENTS ........................................................................................................................ 6 104.1 Strength Requirement ..... ........ ... ...................... ..... ...... .................. ..... ...... ....... .. ..........
..... .... ... ..... . .. . 6
104.2 Serviceability Requirelncnt. ............................................................................ ....................... .....
................. .. 6
104.3 Analysis ......... ....... ........ ...... .. .... ...... .. ............... ........................................................ ................. ...... ........... .................. 6 104.4 Foundario n In vestigation .... ....... ..... .. ...... ,... ,.......... .. .. ...... ............ .. .............. ... .. ....... ..... ....... ... ... ...... .... .... ........ ,.... ,.. 7 104.5 Design Review ........ ..... .. .......... ............. ....... ...... ..... ...... ........... ................. ............. ...... .................... .. ..................... .... 7
SECTION 105· POSTING AND INSTRUMENTATION ..................................................................................................... 7 105.1 Posting of Live Loads ......................... ........ ............ ........... .... ........ ........... .... .. 105.2 Earthquake-Recording Instrumen tation .. ... ... ........... ........... ....... .... ..
............ .. .. ............. ...... 8 .. ........ ............ .... 8
SECTION 106 . SPECIFICA TJONS, DRA WINGS AND CALCULA TlONS ....................... ............................................. 8 106. I General... .............. ........... ................... ............ .. ............ .......... ................ ... .... ........ .. ............. 9 106.2 Specifications........ ........ .. .... ........ ...... ............................. .................. ................ .. ........ ........... 9 106.3 Design Drawings ............ ................. ............... ....................... ................. .. .... 9 106.4 Calculalions .. .......... ................ .... .. ................ .. ...... ........... .. 10 106.5 As-built Drawings.... ....... ... ......... ............ ....... ........... ... .......... ..... .... .......... ..... . .. 10
SECTION 107· STRUCTURAL INSPECTIONS, TESTS AND STRUCTURAL OlISERVATIONS ......... .................. II .. ...... .. ....... 11 107. 1 General............................................ ............................................................. ........... ........... .......... . 107.2 Definitions .. ............... ................. .......... .. .. .. .......... ...... .. ...... .. ................................. .. ............................ .. .................. II 107.3 l nspcction Program ...... .. .. .............................................................. ....................... .. ............... 12 107.4 Structural lnspcctor ..... ................................................................................................................................................ 12 .................... .. .............. .. ....... 12 107. 5 Types of Work for Inspectio n .. ... ........................ ............ .. . 107.6 Approved Fabricators ........ ......... .. ............... ........ .. .. .. ..................... ........ ...... 14 107.7 Prefabricated Construction ............. ..... .......... .... ........ ....... .. ........... .... ... .. .... .............. .. 14 107.8 Non -Destructive Testing.... .................... ........ ...... . .. .. ...... .. ............ ... 15 107.9 Structural Observatio n ................ .................... .. ...... .. .. ...... ............................................................................. 16
SECTION 108 . EXISTING STRUCTURES ........................................................................................................................ 16 ........................... 108. I General... .... ..................................................................................................... . .. .. ............. 108.2 Mainle nancc ............... ............ ........... . .. ....... .... ........... .. .... .... .... .. .. ..... .. .... .. ..... 108.3 Additions, Alterati ons or Repairs ............ .. ...... ........ . .... 108.4 Chan ge ill Use.. .. .. .... ...... . .............. ...... ............. ..... .............. .... .
16 16 16 17
SECTION 109· GRADING AND EARTHWORK .............................................................................................................. 17 ................................ 18 .. ...... 18 .. ........................ 19
109. 1 General. .................................. ..
109.2 Definitions ...... . 109.3 Permits Required ........ .......... .
lh
National Stru ctural Code of the Philippines 6 Edition Volume 1
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CHAPTER 1 - General Requiremenls
. 19 109.4 Hazards. 109.5 Grading Permit Requi rements ........... ........ .. .... ............................................................................ ............. ...... ............. 19 109.6 Grading I nspection ................................................................................... ................. ... .............. .......... .. .... ............. . . 20 109.7 Complelion of Work ...... ........ ........................................................................................................................ .... ........ 2 1
Association of Structural Engineers of the Philippines
CHAPTER 1 - General ReqUIrements
10J.1 Tille These regul ations shall be kn own as the National Structural Code of the Philippines, Vol. I, 6111 Edition 20]0, and may be ciled 3S such and will be re ferred to herei n as "this code."
Sponsors of an y system of design or construction not within the sco pe of this code, the adequ acy of which had been shown by successful use and by analysis and test, shall have the ri ght to prescnt the data on whi ch their design is based to the bui ldi ng official or to a board of examiners appointed by the buildi ng official or the project owner/developer. Thi s board shall be composed of competent stru ctural engineers anc! shaH have auth ori ty 10 investigate the data so submitted, to require tests, and to formul ate rules go verning design and construction of such systems to meet the intent 0f this code. These rul es, when approved and promulga ted by the building offi cial, shall be of the same force and effect as thc provisions of th is code.
101.2 Purpose The purpose of this code is to provide minimum load requirements for the design of buildings, towers and other vertical st ru ctures, and minimum standard s and guidelines to safeguard life or limb, propert y and public welfa re by regul at ing and con tro lling the des ign. construction. quality of materi als pe rt ain ing to the stntctural aspec ts of all bui ldings and stm clures withi n this j urisdicti on.
101.3 Scope T he provisions of this code shall appl y (() the construc tion,
vertical structures within this jurisdiction. Special structures such as but n Ot limited to si ngle fa mil y dwelli ngs. storage s il o.';, liquid prod uct tanks a nd hydraulic nood control structures, sh ould be rc ferred to special slat e of practi ce literatu re but shall refer to provisions o f' th is code as a mini mulll whe rever appl icable. for additions, altcrations, main tenance. ,md change in w;c of buildi ngs and structures. see Sect ion 108.
Where, in an y specific case, different sec tions of thi s code specify different materi als, methods of construction or oth er requiremen ts. the mos t res tri cti ve prov isions shall govern exce pt in the case of single fam il y dwcll ings. Where there is a conflict between a gcneral require ment ilnd a specillc rC(luircmcnt. the specific rC{luirement shall he ap plicable .. 101.4 Alternative Syslems Th e provi sions or this code
co nstructioll
nOI
1-3
spccilically prescribed by Ih is code.
provided ,Ill Y allcrnatc has been permilled and its li se authorized by th~ building official (sec Section 1(2).
National Structural Code of th e Philippines
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Edition Volume 1
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CHAPTEH 1 - General Requiremen ts
art ificially built up or composed of pans joined together in some defi nite manner.
For the purpose of this code. certain terms. phrases. words and their deriv:ui\'es shall be confirmed as specified ill this chapter and else where in this code where specific definiti ons arc provided. Terms. phrases and words lIsed in th e. singu lnr include the plural and vice versa. Term s, phrases and words IIsed in the IllClscu 1i :;p. gender include the feminine and vice versa.
STRUCTURAL ENG IN EER is a registered Civi l Engjneer wit h special qualificati on in the practice of Structura l Engineering as recognized by the Board of Civil Engi neerin g of the Professional Regu lat ion Commission as endorsed by th e Philippine Institule of Civil Engineers (PICE) through the Association of Structural Engineers of the Philippines (ASEP) or special ist members of the Structural Enginccring Specialty Division of PICE.
The follo wing terms arc defined for usc in this chapter: ADDITION is an extension or increase in fl oor area or height of a bu ilding or SlrUClUre. ALTE R or ALTERATION is any change. addition or Illodific
APPROVED as to IllHlcrinls and types of COllslJuct ion, refers to approval by the building official as the result of invcstig.uioll and tests conducted by the building officii!), or by reason of nccc ptcd principles or tests by recogn ized auth oriti es, tedillical or 5c icnt iric organiz.ations. AUTHORITY HA VING JURISDI CTION is the organi zat ion, political subdivision , omce or ind ividual
chHrged with the responsibilit y of ildminislering and enforcing the provisions of this code . BUILDING is
civil
cnginee r
OCCUPANCY is Ihe pUlpOSC for which a bui lding or othe r structures or part thereof. is lIsed or intended to be used .
STn UCTURE is thil l which is buill or constmctcd, an edifice or bu ilding o f any kind. or any piece of work
Assor.i<1tion of Siructura l Engineers of the PhilippInes
CHAPTEFl. 1 -- General fiequirements
1-5
Table 103-1 - Occupancy Category OCCUPANCY OR FUNCTION OF STRUCTURE
OCCUPANCY CATEGORY
Occupancies having surgery and emergency treatment areas, Fire and police stations,
103.1 Nature of Occupancy Buildings and other structures shall be classified, based on the nature of occupancy, according to Table
I03~1
Garages and shelters for emergency vehicles and emergency aircraft,
for
purposes of applying wind and earthquake in Chapter 2. Each building or other structures shall be assigned to the
I"
Stnlctures and shelters in emergency • preparedness centers, A viation control towers,
highest applicable occupancy category or categories.
Structures and equipment in communication centers and other facilities required for emergency response,
Assignment of the same structure to multiple occupancy categories based 011 usc and the lype of loading condition being evaluated (e.g. wind or seismic) shall be pennissiblc.
I
Essential
Facilities
Facilities for standby power-generating equipment for Category I structures, Tanks or other structures containing housing or supporting water or other firesuppression material or equipment required for the-protection of Category I, II or III structures,
When buildings or other structures have multiple uses (occupancies), the relationship between the uses of
various parts of the building or other structure and the independence of the structural system for those various parts shall be examined. The classification for cach indcpendent structural system of a multiple-use building or other structure shall be that of the highest usage group in any part of the building or other structure that is dependent on that basic stJ1lctura! system.
Public school buildings, Hospitals and Designated evacuation centers.
II Hazardous Facilities
-
Occupancies and structures housing or supporting toxic or explosive chemicals or substances, Non-building structures storing, supporting or containing quantities of toxic or explosive substances. -,Single-story school buildings Buildings with an assembly room with an occupant capacity of 1,000 or more, Educational buildings such as museums libraries, auditorium with a capacity of 300 or more students,
III Special Occupancy Structures
Buildings llsed for college or adult education with a capacity of 500 or more students, Institutional buildings with 50 or more incapacitated patients, but not included in Category I, Mental hospitals, sanitariums, jails, prison and other buildings where personal liberties of inmates arc similarly restrained, All structures with an OCCllp~I11Cy of 5,000 or more persons,
..
Structures and equipment in powergenerating stations, and other public utility facilities not included in Category lor Category 11, and required for continued operation,
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National Structural CodE) of the PllilipPlnes
Gill
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Edilion Volume 1
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CHAP TER 1 ... General ncquirements
Table 103-1 (con tinued ) - Occupancy Category OCCUI' AN CY OCCUPANCY OR FUNCTION OF CA TEGOR Y _. STRUCTURE IV Stlil1 dard AI! structu res housing occupanc ies or Occupa ncy h,lving runctioll s not listed in Category l, Structures II or III and Category V. I' Misccll aneo us
Struct ures
Private garages, c:lrports, sheds and feLlces over 1.5 III high.
104.1 Strength Requirement Buildings. LOwers and oth er ven ical structures and all portions thereof shall be des igned and constmcted to sustain , within lhe limitations specified in (his code, all load s set forth i ;l Chapter 2 and eJsewhen~ ;n tli! .'; code, combined in acco rdance with Section 203. Des ign shall be in accordance with Strcngth rk:-.tg;;, L..()ad a nd Resistance Facto r Design and An ~,\'.' ;it'd~ S tress Design methods , as pennittcd by the appl i":J.b lc material chapters.
Ex:ception: Unless otherwise required by the building official, buildings or portions thereof thai llre cOllstructed in accordaJlce willi fh e cOllvemionai Iigllt·framill8 requirements sp ecified in Chapter 5 and the NSCP Volume III 011 Housing sholl be deemed (0 meet rhe requiremelllS of this section. 104.2 Se r viceability Requi rement
J 04.2. 1 Gene r a l Stru ctural systems and me mbe rs thereof shall bc designed to have adequ a tc stiffness to limit deflect ions, lateral dri ft s, vibrati on, or any other deformations (bm adversely affect the inte nded usc and performa nce of' buildin gs lowers and ot her vert ical struct ures . The design shall a lso cons ider durahil ity, resistance to exposure to weather or aggressive env ironment . crac k contro l, and other cond i tions Ih<.11 affect the int ended usc and perform ance of buildings, towers il nd other vertical struct ures.
104.3 Analysis Any sys tem or me thod of construction to be used ..shall be based o n a rational analysis in accordance with well established principles o f mechanics that take into account equilibrium, general stability, geometric comp
Association of Siructuwl Engineers of U)e PhilI ppines
C HAPTEfl 1 - General riequiremenls
104.3.1 S tabilit y Aga ins t O ve rturnin g Every Slniclurc shall be designed (0 resist the ovcI1urning effects caused by Ihe latera l forces specified wi th adequa le Faclor of Safely (FOS). See Secli o n 206.6 for n::(a ining wil lis, Section 207 fo r wind loading and Section 208 for earthquake loadi ng. 104.3.2 Self-S trai ning Fo r ces
provisions shall be made for anticipated self-straining forces ilrising frolll diffcrcmial St!\lh:;llcnl of foundntions and from restrained dimensional changes due 10 Icmpcnlturc, moi sture. shrink.lgc. heave, creep and simi lar effects. 104 .3.3 Anchora ge Anchorage of Ihe roof to walls and columns. and of walls
and columns to foundations shall be provided and adequately de tailed to resist the uplift and sliding forces that result from Ihe applicatioll of the presc ribed fo rces. Conc rete and masonry wa lls shall he anc hored to all floors. roofs and m her struclU ral cleme nts Ihat prov ide latera l su ppon for the wa ll. Such anchorage shall provide a pos iti ve d irect con nec ti on capab le of resis ting the hori zo ntal forces speci fied in Chapter 2 but not less th~n the minimum fOfces in Section 206.4. in add iti o n, in Seismic Zone 4. diap hragm to wall ancho rage lIs ing embedded straps shall have Ihe straps illlached to or hooked arou nd the reinforcing steel or otherwise term inatcd so as to effec ti vel y trn nsfe r forces to the rein forc ing steel. W
1·7
104.5 Design Review The design calculations, drawi ngs, specificatio ns and other design rel ated documents for buildings, lowers and other vert ical structures with irregu lar configuration in Occupancy Categories J. II or III wi thin Seismic Zone 4. struclu res under Altemalive Systems in hem lO l A, and Undefined SllUclural Systems nOI lisled in Table 208-11, shall be subject to a review by an independent recognized structural engineer or engineers to be employed by the owner in accordance with the ASEP Design Pee r Review GuideHni:S. The stroclural engineer or structural engineers performing the review shall have comparable qualifications and experience as the structural engineer responsible for Ihe design. The reviewer or reviewers shall obtain a profess iolHll waiver fro l11 the engi nee r·ofrecord who shall be ex pected to grant suc h waiver in keeping with et hical standa rds of the profession as "dopted in ASEP guidelines for peer review, The des ign review shall , as a mini mum , veri fy the general compli ance with thi s code which shall illcJ ud e, but not be lim ited to, the review of the des ign load cri teri a, the des ign concept . mat hemat ica l mode l and tech niques. The followin g may also be verified, thal th ere are no maj or errors in pe rtinent ca lculali ons, drawings and specificati ons and may also ensure th at the struClUre as rev iewed, meet mi nimu m standards for safcty, adeq uacy nnd acceptable standard des ig n practi ce. The engincer-o f· reco rd shall submil the p lans and specificat ions, a signed and scaled sta tement by the structural engineer doing [he review thal the above review has been performed and that minimum standards have been mel. See Section 208.6.6.3.2 for design rev iew requirements when nonlinear timc·hislory ana lysis is used for earthquake design . In kccping wilh Ih e elhical slandards of Ihe profe.~sio n , Ihe reviewer or reviewers shall not supplant the engineer·on· record as cngineer-on· rccord for the project. The design review shall not in any way transfer or diminish the responsibility of the engineer·of-record . .; .~;\~;~~:~~;~< .:·.Jl~:}; ~;: ~,;~ ~~~;~..:!::~;:.~··-;~~~i rtisYf.~~~~~-~~: ~ '~~:~+~~;.~1~·
Detililcd requirements for foundation investigations sha ll
be in acc.:ordance with Chapter 3 of this code.
Natlollfll Str uc tural Code of U'le Plli1ipplnes 6
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Edition Volume 1
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CHAPTEIi 1 -- General Requirements
105.1 Posting of Live Loads The live loads for which each floor or pOliion thereof of a commercial or industrial building has been designed shall have such design live loads conspicuously posted by the
Phivolcs or the authorities having jurisdiction shall make arrangements to provide, maintain and service. the instruments. Data shall be the propcl1y of the authorities having jurisdiction. but copies of individual records shall be made available to the owner of the building and to the public on request and after the payment or an appropriate fcc.
owner in that pari of each story in which they apply, using durable metal signs. It shall not be allowed to remove or deface such notices. The occupant of the building shall be responsible for keeping the actual load below the allowable limits.
105.2 Earthquake-Recording Instrumentation 105.2.1 General Unless waived by the building official, every building in Seismic Zone 4 over 50 m in height shall be provided with not less than three approved recording accelcrographs. The acceJerographs shall be interconnected for common start and common timing.
105.2.2 Location The instruments shall be located in the basement, midpOliion, and near the top of the building. Each instrument shall be located so that access is maintained at all times and is unobstructed by room contents. A sign stating "MAINTAIN CLEAR ACCESS TO THIS INSTRUMENT' shall be posted in a conspicuous
location.
105.2.3 Maintenance Maintenance and service of the instruments shall be provided by the owner of the building, subject to thc monitoring of the building official. Data produced by the instrumcnts shaH be made availablc to the building official or the Philippine Institute of Volcanology and Seismology (Phi voles) on request.
105.2.4 Instrumentation of Selected Buildings All owners of existing structures selected by the authorities having jurisdiction shall provide accessible space for the installation of appropriate earthquakcrecording instruments. Location of said.instnlments shall be determined by Phivo!cs or the authorities having j lJ ri sci i ct ion.
Association of Structural Engineers of tile PlliliPPlfws
CHAPTER 1 - General Requiremen
1-9
106.3.2.1 General Inrormation
106.1 General Copies of tlcsign c'1Jculations, repon s. plans. specifications and inspection program for all conSllllctions sh;'11i bear the signtllurc and seal of the engi neer-of-record. 106.2 Specifications The specifications shall contain infonnatiol1 cavcling the
I.
Name and date of issue of buildi ng c .' ; and supplements. if an y, to which the des:gn conI ' i ,1$.
2.
Strcngths or designations of material s
3.
Design strengths of underlying sailor f"ck. or rock profile. when ava ilable, shall be !TOV'
I .. ..; li. ( ...: ,
:lC
des il~ll aJ :
Live loads ,lHd other loads lIsed in indicated in the Ooor plans,
5.
Seismic design basis induding the tow! b;·, ',,: shear coeffi cicnt ; a description of the laterH! ~ ;Id -r i:·! :ng sys tem ; and the fundamenta l natur<:;i " '1<" .; .• he design in each direction under considc!... ,.. 11
6.
Provisions for dimensio nal changes ,,('<;;' 11; f !'rom creep, shrinkage. hea ve and tem perature.
106.3 Design Drawings
l:"'!J" ly
7.
Camber of t!usses, beams and girders , ,1' "gll" : .
106.3.1 General The design drawings shall be drawn to scale on durable
8.
Explanation or definition of abbreviations lIscd in the drawings.
paper or cloth lIsing permanent ink and shall be of su ffi cient clarity 10 ind icate the location, n
9.
of the work proposed. TIle drawings shall show a co mpl ete design with sizes, secti ons, rel at ive locatio ns and connecti on detaits of the various members. Floor levels, column cenlers and offsets shall be dimens ioned. Where avai lable and feasible, nfchive copie.~ shall be maintained in durable mediu lll such as compact disc (CD)
Engineer's professional license mn ,ll.;, · expi ration date of the cu rrell! Profession:d Rc' -I' Co mmission reg istration,
106.3.2.2 Stru ctural Concrete I.
and digilal versalile disc (DV D).
;--;Yl !m -
Specified compressive st rength if'c) o [ statcd ages or stages of construction 'n;part of st ructure is designed, The 28 ,; strength (J'..) shall be the basi s of desir"
106.3.2 Required Ini~r;~~tio n . The design drawings s hall cont ain, but shall nOl be limited to the general information listcd in SCClion 106.3.2_1 and material specific infonnatiol) lis ted in Sections 106.3.2.2 and 1063.2.3. as applicab le.
soil
d.
4.
material and constructi on requirements. The material s and
cons truction requirements shall confonn to the specifications referred to in Chapters 3 to 7 of thi s code.
lu
!
W
' . H;
-,
,': 1 SC/" . (
2.
Anchorage embedme nt lengt hs or CI ' . l r pC' I steel reinforcement and locati on and L.·nglh splices_
1.
Type and location of welded splices i!n'! cOllncctions of reinforce ment.
4.
Magnitude and location of prcstrcs!-ol iig includi ng prestressed cable layout.
5.
Minimum concre te compressive st reng: > if'.- ) of posHension ing,
6.
Strcssing seque nce for post -tensioned I(!: ,' . . ii .' ,
7.
Dctails lind location of all cOFll racli { , joints specifi rc! for plain concrete in ::;(:;. <
8.
.(s
,.:
Statemcnt if conc rcte slab is designi.·d , .: .n.
diapllragm. 421.9.4.
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_ _ __ • _ _ _ _
• _ _ • _ _ _• _
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NC1tlonnl Stru ctuwl Code of the Philippines G Edition Volume 1
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CHAP TE Ii 1 -GeneralliequiremenlS
106.4.3 Compuler Programs Calculations Illay include the results from an electronic
106.3.2.3 Structural Steel
digital computer analysis.
I.
apply
2.
T ype or types of construction as defined in Sec ti on 501.3.
3.
Th e type o f con nection for joints using
A dra wing of the complete mathematical model used to represent the struc ture in the computer-ge nerated ana lys is shall be provided. Design assump tions shall be clearly desc ribed .
2.
A program description giving the program name, the
ve rsion number, and the company whi ch developed
high~ strcngth
lhe program and its address shall be provided as part of the computation docum entati on. A program User's Guide shall also be made avai lable, upon request, and shall contain the information to determine the nature and ex lent of the analysis. verify the input data, interpret the result ,
boils. 4.
For welded joints, Type I connections shaU not be allowed.
5.
Stiffener and bracing requirements.
6.
Description or explanation of welding and inspec ti on
computations comply wi th the requirements of this code.
sy mbols used in the design and shop drawing s. 7.
Notes for joints in which welding sequen ce and
3.
Data provided. as co mput er input shall be clearly distinguished from th ose computed in tile program. The information required in the output shall include date of processing. program identification, and identification of structures being analyzed, all input data, units and final results . An archived copy of all computer runS shall be stored in CD or DVD.
4.
The firs! sheet of each co mput er run shall be signed
technique of welding arc required to be carefully controlled to minimize distoI1ion.
106.4 Calculations 106.4.1 General Calculations pertinent to the Slnlctu ral design of structures and its component members shall be filed with the des ign drawings.
106.4.2 Basis of Design Summary The calc ulation s s h~1l include a summary o f the. crilCria a nd methodologies Il sed in the design. Th is summ ary shall include, but need not be li mited lO, tile folJo\, . . ing: J.
Name ,llld date of issue of building code and supp lc melH s, if any, to which the design conforms.
2.
Strengths or designations of materials to be used for each co mponent of the structure.
3.
Design stre ngt hs and other design parameters of the underlying soi l or rock.
4.
Li ve loads and other loads lIsed in design.
5.
Th e b'1Sis of the seismic an d wind design forces.
6.
A ucscriptioll of the stl1lclUre's grav it y and lateral Jmld resistin g sys tems. A. description of Ihe roof. Il oor. foundation and olher com pollc nt !iystel11s sllilll also he pro vi ded .
7.
A descri pt io n procedures ust!d ill tile struclUral il!lal ysis. Thi s slwH incl ude the section and Jlwtcrial proP{~Jlic s used, loading co mbinati olls co nsidt! rcd, scc() l1d ~ ordcr ellerts considerati ons, lIlId any sill1pl ifying as~umplions made.
The following requirements
calculations which include such computer output:
1.
Loads and design requireme nt s necessary for preparation of shop drawings including shears, moment s a nd ax ial forces to be resisted by all members and their connections.
to
and sealed by the engineer-of-rccord.
106.4.4 Model Analysis Rcsuhs from modcl antl lysis
106.5 As·built Drawings As-built drawings shall be prepared by the constl1lctor or a perso n rettlillcd to provide such services to docllment the wo rk as actually constru cted . The as-buil t drawi ngs shall be drawn lO scale upon durable pilpcr or cloth llsing
pe rm anent ink and shall illdicnte Ihe sizes, sectio ns, relative locati ons. ~lI\ d cOll llecl ion deta ils of the vari ous st ructu ral members as acltl;tlly co nstructed . Strengths of materials, based on required tesls. sha ll
drawi ngs fil ed wilh Ihe build ing officii'll shall he accordingly mark ed in the a s~b llilt drawings and pro v!dt!d with noll'S indicating the ha sis of such modifications or changes. The bas is of modifi ca tion ' or ch'lIl£c shall include reference to sllppk1llcntal design draWings, conslruction bulletins, or instru ctio!ls from the owner,
Association of StfUc!ural En})li"lcers of the
Ptlllipplne~ ;
CHAPTER 1 - General Requirements
1-11
owner's representative or structural engineer authorizing such modifications or changes. The signature, seal, name and professional license number of the civil engineer in charge of construction shall be included in the as~built drawings. Copies of the as-built drawings shall be provided to the owner, constructor, engineer~of~record and the building
107.1 General All construction or work for which a permit is required shall be subject to inspection throughout the various work stages. One or more structural inspectors who are registered civil engineers with experience in structural construction, who shall undertake competent inspection during construction on the types of work listed under Section 107.5, shall be employed by the owner or the engineer~of~ record acting as the owner's agent.
Exception: The building official may waive the requirement for the employment of a structural inspector if the construction is of a minor nature.
In addition to structural inspections, structural observations shall be performed when required by Section 107.9. 107.2 Definitions The follo'wing tenns are defined for use in this section: CONTINUOUS STRUCTURAL INSPECTION is a structural inspection where the structural inspector is on the site at all times observing the work requiring structural inspection.
PERIODIC STRUCTURAL INSPECTION is a structural inspection where the inspections arc made on a periodic basis and satisfy the requirements of continuous inspection, provided this periodic scheduled inspection is performed as outlined in the inspection program prepared by the structural engineer. STRUCTURAL INSPECTION is the visual observation by a structural inspector of a particular type of construction work or operation for the purpose of ensuring its general compliance to the approved plans and specifications and the applicable workmanship provisions of this code as well as overall construction safety at various stages of construction. STRUCTURAL OBSERVATION is the visual observation of the structural system by the stI11ctural observer as provided for in Section 107.9.2, for its general conformance to the approved plans and specifications, at significant construction stages and at completion of the structural system. Structural observation docs not include
th
National Structural Code of the Philippines 6 Edition Volume 1
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CHAPTER 1 -General Requiremenls
or waive the responsibilily for the structural inspections required by Section 107. I or other sections of this code. 107.3 Structural Inspector
I. 'Concrete jor,foundations of resillelllial !JUi/dings accommodating 10 or ~fewer persons, or - b!li1d~ngs fal1i~i l""'er Category V of Table 10}·1, provided the buitding officwl finds tllat a ' structural IIaZ{lrd
does not exist. 107.3.1 Qualifications
The sU'uctural inspector shall be a registered civil engineer who shall demonstrate competence for inspection of the particular type of construction or operation requiring structural inspection.
107.3.2 Duties and Responsibilities The structural inspector shall observe the work assigned for conformance (0 the approved design drawings and specifications. Any discrepancy observed shall be brought to the immediate attention of the constructor for correction, then, if uncorrected, to the owner andlor to the building official. The structural inspector shall verify th at the as·built drawings (see Section 106.5) pertaining to the work assigned reflect (he condition as constructed, The structural inspector shall also submit a final report duly signed and sealed stating whether the work requiring stru ctu ral inspection was, to the best of the inspector's knowledge, in confonllance to the approved plans and specifications and the applicable workmanship provisions of thi s code.
2.
For foundation concrete, otlier than cast-ill-place drilled piles or caissons. where the structural desigll is based on alit, 1Iot greater tha1l 17 MPa.
3.
Non-structural slabs on grade, lnclllding prestressed slabs on grade when effective prestress in concrete is less rhan 10 MPa.
4.
Site work concrele fully supported on earth and concrete where no special hazard exists.
107.5.2 Bolts Installed in Concrete Prior (0 and during the placement of concrete around bolts when stress increases permitted by Section 423 are utilized. 107.5.3 Special Moment-Resisting Co ncrete Frame For special moment-resisting concrete frame design seismic load in structures withill Seismic Zone 4, the. slructurru inspector shall provide reports to the engineerof-record and shall provide continuous inspection of th e.
placement of the reinforcement and concrete. 107.5.4 Reinforcing Steel and Prestressing Steel
Tendons 107.4 Inspection Program The structuraJ inspector shall prepare an appropriate testi ng and inspection program that shall be submitted to the building official. He shall designate lhe ponions of the work that req uires structural inspections. When structural observation is required by Section 107 .9. the inspection program shan describe the stages of construction at which structural observatio n is to occur, The inspection program shan include samples of inspection reports and provide time limits for submi ssio n of reports.
107.5.4.1 During a ll stresSing and gro uting of tendons
in prestressed concrete. 107.5.4.2 During )llacing of I'einfol'ci ng steel and
prestressing tendons for all concrete required to have structural inspection by Section 107.5.1.
Exception:
The st11lctural inspector need not be presel!! continuously during placing of reillforcing steel and prestressing tendons, provided the structural inspector has inspecfed for confonnance to the approved plalls prior to flu: closing offonns or the delivery of concrete 10 the jobsit l'.
107.5 Types of Work for Inspection Except as provided in Section !o7.1. the types of work listed below shall be inspected by a structural inspeclor. 107.5.1 COllcrcte During the laking of test specimens and placing of concrete. See Section 107.5.12 for shoterete.
£:.ccepliol.'s: ·
.. '.
Association of Structural Engineers of the Philippines
CHAPTER 1 - General Requirements
107.5.5 Structural Welding
1-13
107.5.5.1 General
of bolts to determine that all layers of connected materials have been drawn together and that the selected procedure is properly used to tighten all bolts.
During the we lding of any member or connecti on th at is designed to resist loads an<\forces required by this code.
107.5.7 Structural Masonry
,
Exceptions: 1.
Welding dOlle in on approved fabricator's shop in accordance witli Sec/ion 107,6.
2.
TI,e _~tmctural inspector need not be cOllfinuously presem dwine welding of the following ilems, provided the materials, qualifications oj welding procedures and welders are verified prior 10 the start of work; periodic inspections are made of work in progress; and a visual inspection of all welds is made prior 10 completion or prior fa shipment of shop welding: oj Sing/ewpass fillet welds no/ exceeding 8 mm
in sileo b) Floor and roof deck welding.
107.5.7.1 For masonry, other than fully grouted openend hollow-unit masonry, during preparation and taking of any required prisms or test specimens, placing of all masonry units, placement of reinforcement, inspection of grout space, immedhHely' prior to closing of cleanouts, and dUl'ing all grouting operations.
Exceptioll: For hollow-unit masonry where the fm is no more than 10 MPa for concrete Ilnits or 18 MPa for clay ullits. structural inspectioll may be peifonned as required for fully grouted open-end hollow-unit masonry specified ill Section 107.5.7.2.
c)
Welded studs when used for structural diaphragm or composite systems.
d)
Welded sheet steel for cold-fanned steel framing members such as studs alld joists.
107.5.7.2 For fully grouted open-end hollow-unit masonry during preparation and taking of any required prisms or test specimens, at the start of laying units, after the placement of reinforcing steel, grout space prior to each grouting operation, and during all grouting operations.
e)
Welding of stairs and railing systems.
Exceplion:
107.5.5.2 Special Moment-Resisting Steel Frames During the non ~destru clive testing (NDT) of welds specified in Section 107 .8 of this code, the use of certi fied welders shall be required for welding structural sleel connections for this type of frame. Crirical joint connections shall be subjected to non-destructive testing usi ng certified NDT technicians.
S,ructural inspection as required ill Sec/iolls 107.5.7. J and 107.5.7.2 need not be provided when design stresses have been adjusted as specified in Chapter 7 to permit noncontinUous inspection. 107.5.8 Reinforced GYPsulIl Concrete When cast-in-place Class B gypsu m concrete is being
mixed and placed. 107.5.5.3 Welding of Reinforcing Steel During the non -destruct ive testing of welds.
107.5.6 High-Strength Bolts The inspection of hi gh-strength A325 and A490 bolts shall be in accordance with approved internationally recognized stanqards and the requirements of this section. While the work is in progress, the stnJclUral inspector shall determine that the requiremenls for bolts. nuts, washers and paint: bo iled parts; and in:,t allali on and lightening in such standards arc mel. Suc h inspections may be perfonncd on a periodic basis as defined in Section 107.2.
J07.5.9Insulating Concrete Fill During the application of insulaling concrete fill when used as part of a structural system.
Exception: ]fIe slmctural inspections may be limited. to an illitja~ inspection to check the deck sUrface and placement of reinforcing Sleet. 11le slructural inspector shall monitor rhe preparation of compression test specimens during this initial inspection.
The st ructural inspector shall observe the calibration procedu res when such procedures are requi red by lhe plans or specifications. He shall monitor lhe installation
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National Structural Code of the Philippines 6 Edition Volum e 1
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CHAPTER 1 - General Requirements
107.5.10 Spray· Applied Fire-Resisti ve M a terials
2.
Verification of the fab ri cator's qUal it/ ~ontrol capabi lities, plant and person nel as outl illed !Jl the fab rication procedura l manual ~ lla ll b ~ ; ~)' an approved inspection or quali ty control dgcllt.y .
3.
Peri odic plant inspections shall be conducled by an approved inspection or quality con trol agency [0 monitor the effectiveness of the quality co ntrol program.
Du ring the application of spray-applied fire-resistive materials ..
107.5. 11 Piling, Drilled Piers and Caissons During driving and load testing of piles and construction of cast-in·place dri lled piles or caissons. See Sections 107.5. 1 and 107.5.4 for concrete and rei nforcing steel inspection.
107.7 Prefabrica ted Cons tructi on 107.5.12 Shotcrete During the (aJdng of lest specimens and placing of all
107.7.1 General
sholcrelc. 107.7.1.1 Purpose The purpose of this section is to regulate materials and
Exception:
Shotcrete work f ully supponed all earth, millor repairs and when, in the opinion of the building official, 110 special hazard exists.
establish meth ods of safe construction where any struc ture or portion the reof is wholl y or panial ly
107.5.13 Special Grading, Excavation and Filling
107.7.1.2 Scope
During earthwork excavations, grad ing and fi lling operatio ns ins pection to satisfy req uireme nt s o f Cha pter 3
Unl ess otherwise specifically stated in thj s scct ion , all prefabricated co nstructi on and all materials used therein
and Section 109.5.
shall conform to all the req uirements of Secti on 101.4.
107.5.14 Special Cases Wo rk that, in the opinion of the stn lclural engineer,
107.7.1.3 Definition
prefabricated.
involves unusual hazards or condi tions.
PREFABRICATED ASS EMBLY is a stru ctural uni t.
107.5.15 Non-Dest ru ctive Testing
the integral parts of w hi ch have been built up or assembled prior to incorporation in the buHding.
In-situ non-destructive testing program, in addition to the requirements of Section 107.8 that in the opinion of the structural engineer may supplement or replace conventional lC!HS 011 concrele or olher materials and
assemblies. 107.6 Approved Fa br ica tors Structural inspections required by this section and elsewhere in this code are not required where the work is done on the premises of a fab ricator approved by the structural engineer to perform such work without structural inspection. The approved fabrica tor shall submit a certi (icate of compliance Lhat the work was
performed in accordance with the approved plans and specifications to the building official and to lhe engineer
or architect of record. The approved fabricator's qualifications shal! be contingent on compliance with the following : I.
The fabricator has developed and submiltcd (l detai led fabrication procedur:ll manual rcnect ing key q uality cont rol procedures Iha t wi ll provi de a basis fo r inspect io n con tro l of work mansh ip and the rabricator plan t.
107.7.2 Tests of Materials Every approval of a material n01 specifically mentioned in this code shall incorporate as a proviso the kind and number of tests to be made during prefabrication.
107.7.3 Tes ts of Assembl ies The building official may require special tests to be made 011 assemblies to dctermine thei r structural adequacy, durabili ty and weather resis tance.
107.7.4 Connec ti ons Every device used to connect prefabricated as!\(,-II'b! i('~~ sllall be designed as required by this code and : j , _; : j>c
capable of developing the strength of the largest ,;" ;l1ber connected, except in the case of members fenning part of a sll1.lcwral frame designed as specified in ampler 2. Connections shall be capable of withstanding uplifl forces as specified in Chapter 2. 107.7.5 Pipes a nd Co nduits In structural design. due allowance shall be mack fo r any mate rial to be re moved or d isplaced for tile inxla lia lion of pi pes, co nduits or ot her equipment.
Association of Structural Engineers of th e Philippines
CHAPTEfi 1 - General Hequirements
107.7.6 Certificate and Inspection 107.7.6.1 Materials
Materials and the assembly thereof shall be inspected to determine compliance with this code. Every material shall be graded, marked this code.
Of
labeled where required elsewhere in
107.8.2.1 General All complete penetration groove welds contained in joints and splices shall be tested 100 percent either by ultrasonic testing or by radiography.
l!.,xceptions: 1.
When approved, the non-destructive testing rate for an individual welder or welding operator may be re.duced to 25 percent, provided the reject rate is demonstrated to be 5 percent or less of the welds tested for the welder or welding operator. A sampling of at least 40 completed welds for a job shall be made for such reduction evaluation. Reject rate is defined as the number of welds containing rejectable defecls divided by the number of welds completed. For evaluating the reject rate of continuous welds over 900 mm in length where the effective throat thickness is 25 mm or less, each 300 mm increment or fraction thereof shall be considered as one weld. For evaluating the reject rate on continuous welds over 900 mm inlenglh where the effective throat thickness is greater than 25 mm, each 150 mm of length or fraction thereof shall be considered one weld.
2.
For complete penetration groove welds on materials less than 8 mm thick., non-destructive testing is not required; for this welding, continuous inspection is required.
3.
When approved by the building official alld owlilled in the project plans and specifications, this nondestructive ultrasonic testing may be performed in the shop oj an approved fabricator utilizing qualified le.st techniques in the employment of the fabricator.
107.7.6.2 Certificate A cCI1ificate of acceptance shall be furnished with every prefabricated assembly, except where the assembly is readily accessible to inspection at the site. The certificate of acceptance shall certify that the assembly in question has been inspected and meets all the requirements of this code.
107.7.6.3 Certifying Agency To be acceptable under this code, every certificate of approval shall be made by a nationally or internationally recognized cCltifying body or agency. 107.7.6.4 Field Erection Placement of prefabricated assemblies at the building site
shall be inspected to detennine compliance with this code. 107.7.6.5 Continuous Inspection
If continuous inspection is required for certain materials where construction takes place on the site, it shall also be required where the same materials are used in prefabricated construction. txceplioJ1: Continuous inspection )'1 ill not be required during prefabricariol1 If the approved agency cerlz(ies to the consfruction andfumishes evidence (~f compliance.
1·15
J
107.8 Non·Destructive Testing 107.8.1 General
In Seismic Zone 4, welded, fully-restrained connections between the primary members of special momentresisting frames shall be tested by nondestructive methods perfonned by certified NDT technicians for compliance with approved standards and job specifications. This testing shat! be a pan of the structural inspection requirements of Section 107.5. A program for this testing shall be established by the person responsible for stI1lctural design and as shown 011 plans and specifications. 107.8.2 Testing Program
As a minimum, the testing program shall include the following:
107.8.2.2 Partial penetration groove welds when used in column splices shall be tested either by ultrasonic testing or radiography when rcquired by the plans and specifications. For partial penetration groove welds when used in column splices, with an effective throat less than 20 mm thick, nondestl1lctive testing is not required; for this welding, continuous structural inspection is required. 107.8.2.3 Base metal thicker than 40 mm, when subjected to through-thickness weld shrinkage strains, shalt be ultrasonically inspected for discontinuities directly behind such welds after joint completion. Any material discontinuities shall be accepted or rejected on the basis of the defect rating jn accordance with the (larger reflector) criteria of approved national standards. 107.8.3 Others The structural engineer may accept or require in place non-destructive testing of concrete or other materials and assemblies to supplement or replace conventional tests.
1h
National Structural Code of the Pllilippines 6 Edition Volume 1
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CHAPTER 1 _.. General Requirements
107.9 Structural Observation 107.9.1 General
Stmctural observation shall be provided in Seismic Zone 4 when one of the foll owing conditions exists: I.
The struct ure is defi ned in Table 103- 1 as Occupancy Category I. II or Ill;
2.
The structure is in Seis mic Zone 4, No as sel forth in Table 208A is greater th an 1.0, and a lateral design is
10S.1 General
Buildings in existence at the time of the adoption of this Illay have their existing usc or occupancy continued , if such use or occupancy was legal at the time of the adoption of this code, provide(1 such cOlllin ued use is not dangerous to life. co~e
required for the entire structure; 3.
4.
When so designated by the stru ctural engineer. Of
When such observation is specifically required by the
Any change in the use or occupancy of any ex isting building or structure shall comply with lpC provisions of Seclions 108.4 of this code.
bu ilding official. I
I
I.
107.9.2 Structural Observer The owner shall empl oy the engincer~of-record or another civ il engi neer to perform structural observation as defined in Section 107.2. Observed deficiencies shall be reponed in writing (0 the owner's represcntati vet structural inspector, constructor
and the building official. If not resolved, the stnlctural observer shall submit to the bu ilding offi cial a written statement duly signed and sealed, idemifying any deficiency. 107.9.3 Cons truction Stages for Observations
The structural observations shall be performed at the construction stages prescribed by the inspection program
IOS.2 Maintenance AI! buildings and structures, both existing and new, and all parts thereof, shall be maintained in a safe condition. The owner or the owner's designated agent shall be responsible for th e maintenance of buildings and structures. To determine compliance with this.subsection, the bui lding official may cause a structure 10 be reinspected. 108.3 Additions, Alterations or Repairs 10S.3.1 General
Buildings and structures to which additions, alterations or repairs are made shall comply with all the requirements of this code for new facilit ies except as specifically provided in thi s section .
prepared as requ ired by Secti on 107.3.
It shall be the dUly of the engineer+in-charge of construction, as authorized in the Building Permit, 10 notify the stmclUral observer that the described constniction stages have been reached, and to provide access to and means for observing the co mponents of the strucrural system. ~~W~~~j!'f~
~~--gp;~~~~~.$~
IOS.3.2 When Allow ed by the Building Official Additions, alterations or repairs may be made to any building or structure without requ iri ng the existing building or st nlcturc 10 co mply wi th ,\11 the requirements of this code, provided the addition, alteration OJ' repair co nforms to that required for a new building or structure and provided further that such appro val by the building official is in writi ng. Additions or alterations shall not be made to an ex isting building or structure that will calise the existing bui lding or Slructure to become unsafe. An unsafe condition shall be deemed to ha ve been created if an addit io n or alteratioll wi ll ca use .IIlY st ructu ra l element of the existing building or SlmClUrc to resist loads in excess of their capacity or cause .1 red ucti on of {heir load cnrrying capaci ty. Ad di tions or alterations shall nOI be made 10 an ex isting buildi ng or structure when suc h existing building or structure is not in full compliance with the provisions of this code except when such addi ti on or alteration will resu lt in {he ex isting building or st ructure bei ng no more
Association of Struclural Engineers of the Philippines
CHAPTER 1 - General Requirements
hazardous based on structural safety, than before such additions or alterations arc undertaken, unless adequate retrofitting or remediation is introduced.
Exceptions: Alterations to exl'sting structural elements or additions of flew structllral elements, wh!'ch are initiated for the plllpose oj increasing the strength or stiffness oj (he lateral-jorce-resisting system of an existing struc/~lre. Ileed not be designed for. forces confonning to these regulations provided that an engineering analysis is submitted 10 show that: 1.
The capacity of existing structural elements required to resist/orces is not reduced;
2.
The lateral force co required errstmg structural elements is not increased beyond their design strength;.
3.
New slnlclural elements are detailed and connected to Ihe existing structural elements as required by these regulations; and
4.
New or relocated nOfl~strnctural elements are detailed alld connected to existing or fl ew structural elements as required by these regulations.
A change in use or occupancy of any building shall be allo wed only when the change in use or occupancy will not cause any structural elemen t of the existing building to resist loads, determined on Ihe basis on this code and on the proposed use or occupancy. in excess of their capacity. Alterations to Ihe ex isting bui lding shall be pemliued to satisfy this requirement. No change in the character of occupancy of a building shaJl be made without a new cenificate of occ upancy regardless of whether any alterations to the building arc
108.3.3 Non-structural Non-s truclural alterations or repairs to an existing bui lding or struclure are rennitted 10 be made of Ihe sam e materi als of whi ch the building or structure is constructed, provided that they do not adversely affect any structural member or lhe fire~resistance rating of any part of the bu ilding or structure.
108.3.4 Historic Buildings Repairs, alterati ons and additions necessary for the preservation, rcstoration, rehabilitation or cominued use of a building or structure may be made without confonnance 'to all the requ irements of this code when authorized by the building official. provided : I.
The build ing Or structure has been designated Iby official action o f the legally constituted authori ty of thi s jurisdict ion as having spec ial historical or architectural signi fi cance.
2.
Any structurally unsafe conditions are corrected.
3.
The reslc!'cd buildin g or structure will be no more
1· 17
hazardous based on life safet y than the existing building.
108.4 C hange in Use No Change shall be made in the charactcr o f occupancies or use of i\ny building unless the new o r proposed lise is less ha7.ardous, hased on life safety than the existin g usc.
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National Structural Code of th e Philippines 6 Edition Volume 1
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CHAPTER 1 '" General Requirements
Geotechnica l Engineeri ng of the Ph ilippi ne In stitute o f Civil En gineers (PI CE).
109.1 General 109. 1.1 Scope
GEOTECHNI C AL ENGINEERING is the "ppli cation of thc princi pl es o f soil and rock mechan ics in the in vestigatio n, eva luati on and dcsign of ci vil works involvin g the use o f ea rth materi als and fo und ations and the inspec tion or testi ng of the construction the reof.
The provis ions of this section apply 10 gradi ng. excavation and can hwork cOll stm . :tio n, includ in g fi lls and c nbankmc rHs.
GRADE is Ihe vel1icill locJli on of the ground su rfacc.
109.2 DefillitiolLs
EXISTING GRADE is the grad e pri or to gradin g.
The fo ll owing terms are defi ned for lise in this sect ion: APPROV AL s hall mean Iha t the proposed work or completed work con forms 10 th is secti on in the opin ion o f th c building offi cial.
FINISH GRAD E is the final grade of the si te that confonns to the approvcd pl an. ROUGH GRADE is the stage at which the grade approximately co nforms to the approved pl an.
AS GRADED is the ex te nt o f surface con dirions o n comple ti on of grading.
G RADING is an excavator or fill or com bination thereo f.
BEDROCK is in· placc solid or altered rock .
K E Y is a designed compacted fi ll placed in a tre nc h excav ated in earth malerial beneat h the toe of a slope.
BENCH is a rel atively level step ex cavated into earth mat eri al on whic h fill is to be pl aced . nORRO\V is earth m3lerial acquired from an off·site loca tion fo r use in grading on a site. CIVIL ENGINEERING is the applicat ion of the kn owl edge of the fo rces of nature, principl es o f mec hanic s a nd the properties of mate ri als to the evaluat ion, design an d constllJc ti o n of civi l works. COMPA C TION is the dcnsir
of a
fill
If)'
EARTH MATERIAL is a ny roc k, natural soi l o r r< 1I or
PROFESSIONAL INSPECTION is the inspection required by thifi code to be performed by th e civ il engineer o r geotechnical e ngi neer. S uc h inspecti ons incl ude tha I perfomled by persons supervised by such engi neers or geologists a nd shall be suffic ient to fonn a n opinio n relating to the conduct of the work. SITE is any lot or parce l of land or cont iguous com binmioll the reof. unde r the same owncrs hi p. where grading is performed or permitted.
SLOPE is an inclined ground surface the inclination of whic h is ex prcssed as a rat io o f vel1ica l distance to horizo ntal di stance.
an y combin ati o n thereof.
SOIL is naturall y occu rring supe rficia l deposi ts overlying EROSION is the wearing away of the grou nd surface as a
bedroc k.
res ult of the movemen t of wi nd, wate r or ice. SOILS ENGIN EER. See Geotechni cal Engineer. EXCAVATION is the mec ha ni cal re moval of earth mate ri al.
SOILS ENGINEEIUNG . See Geotecilili ca l Engineering.
FILL is a deposit of earth material placed by artificial me'I IlS.
TERRACE is a relatively level step co ns tructed in the face of a graded s lope surface for drai nage and mai IIt ena nce purposes.
GEOTECHNICAL ENGINEER is II registered Civ il En gin ee r with spec ial qualifi ca ti on in the prac tice of Geo tec hn ical Engineering as recognized by the Bo.ard of Civi l Engincering of thc Professiona l Regulation Commission as endorsed by the Specially Division of
Association of Structural Engineers of tile Philippines
CHAPTER 1 .- General HequlremenlS
109.3 r)ennits Required 109.3.1 Gencral Exce pt as specified in Section 109.3.2 of this section, no person shall do any gmd ing without first having obtained .1 gra ding pCnllit from the building official. 109.3.2 Exempted Work A grading permit shall not be required for the following: I.
Grading in an isolated.
sc lf~co lllaiJ)cd
area if [here is
1- 19
Sl
no dnngcr to priv'lIc Or public properly.
2.
An excavation below finished grade for basements and footings of a building, retnining wall or other stnlcture authorized by a valid building permit. Thi s shall nol exempt any fill made with the material from such excavation or cxempt any excavation ha ving an . unsupported hcight greater than 1.5 m after the completion of such Slmcture;
3.
Cemetery graves;
4.
Refuse di sposal sites cont rolled by other regulmions;
5.
Exc:lvations for wells, or trenches for utilities;
6.
Mining, quan'ying, excavating, processing or stock piling of rock , sa nd, gravel, aggregate or clay controlled by other regulations. provided slich operations do flot affect the ItHera l suppon of, or increase stresses in, soil on adjoining propeflies;
7.
Exploratory excavat ions performcd under direction of a registcred geotechnical engineer;
8.
An excava ti on that ( I) is less than 600 mm in depth Of (2) docs not create
9.
A fill less than JOO mill in depth and placed on natttrni terrain wi th a slope flatter th
the
in 5 units hori zo ntal (20% slope). Or less than 900 in depth, not imcndcd 10 suppor( structurcs, that docs not exceed 40 Ill) on anyone lot and docs not obSlmct a drainage course.
109.5.1 General Except as exempted in Section 109.3.2 of this code, no person shall do any grading without first obtaining a grading permit from the building official. A separate pem)it sha ll be obtained for each si te, and may cover both excavations and fill s. 109.5.2 Grading DeSignation Grading in excess of 4.000 m) shall be perfonned ill accordance with the approved grading plan prepared by a civil engineer, and shall be designated as "engineered grading." Grading involving less Ihan 4,000 1111 shall be designated "regular grading" unless the permittee chooses to have the grading performed as engineered grading, or the building official determines Ih31 special conditions or unusual hazards exist, in which case grading shall conform to the requirements for engineered grading. 109.5.3 Engineered Grading Requirements Application for a gradi ng pennil shnll be accompanied by two sets of plans and specifications, and supporting data co nsisting of a geotechnicill engineering repofl. Additionally. the application shall state lhe estimated quantities of work involved. The plans and specifi cations shall be prepared and sig ned by the civi l engineer licensed to prepare such plans or spec ifi cations when required by {he build ing official.
111m
Exemption from the pennil requirements of thi s sec ti on shall flot be deemed 10 grant authorization for any work to be done in any manlier in violation of the provisions or this code or any oth er laws or ordinances or this jurisdiction.
Specifications
shall
contain
information covering Plans shall be drawn to scale upon subs tantial paper or cloth and shall be of sufficient clarity to indicate the nature and extent of (he work proposed and show in detail thilt th ey will conform to th e provisions of this code and all rc!e val1l laws. ordinances, rules and regulations . The first sheet of eac h set of plans shall give location of the work, the nam e and ,lddrcss of {he oWlH.~1'. and the perso n hy whom th ey were constmcl ion and malerial requirements.
prcp'l l'cd .
109.4 Hazards Wh enever the huilding offi cial determines lhilt any exLo;;ting excavation or embankment Of filt on private property Il(I~ become a hazard to life and limb, or endangers properly. or Oldvcrscly affects the s"f'ct y. usc or
National Struc tural COCIG of thE: Pllilippll1 es
()Iil
Edition Votume 1
1·20
CHI\P TEIi 1 ... General f1equirerncnls
The plans shall include lhe following information: I.
General vi cinity map of lhe proposed s ite;
2.
Property limits and accurate contours of eX isti ng
3.
4.
of the person who prepared the plan . The pl:m shall include the followin g information :
I.
General vicinity map of the proposed site;
ground and details of terrain and area drainage;
2.
Limiting dimensions a nd depth of cut and fill;
Limiting dimensions elevati ons or f'inhih co ntours to be achieved by the grading, and proposed dmin agc channels and rel ated COnSII1J ction;
J.
Provisions for lateral earth SUPPOI' or shori ng; l.\Ild
Detailed plans of all surface and subsurface drainage
4.
Loca tion of an)' bu ild ings or structures where work is
w be pcr:onned , and the location of any buildings stnJcture ~ \~' ithin
4 .5
III
Or
of the proposed grading.
devices, w;.!Ils, cribbing, dams
109.6 Grading Inspeclion
proposed work, IOgether with a map showi ng the
5.
6.
drainage arc.\ and the estimated runoff of the arc,l
109.6.1 General
serveO by an y drains; Location of a ny buildings or struc tures on the property where the work is to be pcrfonncd and the locatioll of any buildings or s(ruClUres on l:lllu of adjacen t owners that arc within 4.5 m of the property or that may be affected by the proposed grading
Grading operariolls for which a permit is required shall be subject 10 inspection by the building official. Inspection of grading opera tions shall be provided by the geolechnical engineer reHlined 10 provide such services in accordance with Section 109.5.5 for engineered grading
opermiolls;
grading.
Recommendations
included
in
the
geotechnical
enginccling reron and the engincering geology report shall be incorporated in,. the grading plans or speci fi cations. When approved by the building official, specific recommendations contained in the geotechnical engineering report and the engineering geology report, which arc applicable to grading, may be included by reference; and
7.
The dates of the geotechnical engineering :lnd engineering geology repon s toge ther with the names, addresses and phone numbers of the firms or indi vidu als who prepared the reports.
109.5.4 Geotech nical Engineering Report The geo technical engineering re port required by Section 109.53 shall include data regarding the nmure, distributi on and strength of ex.ist in g soi l, conclusions and recomlllendations for grading procedures and design criteria for corrective mcasures, including buttres,-; fill s, when necessary, and opinion on adequacy for the intended usc of sitcs to be devel o ped by the proposed grading ilS affected by gcotechn ica l engineering f.lcwrs. including Ih l~ stabili ty of slopes. Refer to -C hapter :-\ on Excavtltiolls imd Fou ndations for
delililed requ ireme nt s :md gu idel ines. J 09 .5.5 H('g uJ :Il- GnHiing Requirements applicat ion for .1 grading perini I shall l)l~ (I<..:<.:otllpanicd by
Each
109.6.2 Civil Engineer The civil engineer shall provide professional inspection within such engineer's area of tcchnicnl spec ialty, which shall consist of observation and review as to the establishment of line, grade and surface drainage of the development area. If revised plulls arc required during the course of the work, th ey shal! be prepared by the civi l engineer.
109.6.3 Geotechnical Engineer The geotech nical enginee r shall provide obscrvation duri ng gradi ng a nd tc~tin g for requ ired compaction . The geotcc hn ical engineer shall provide s ufficiclll observation during the prep
109.6.4 I>enllittre The pcrmilLcc s hall he res po nsi hle for the work to he performed in accordancc wi th th e approved pla ns and spcc ifie;:ltin ns and in conformil llce with th e provisions or Ihis code. and the pcrmillce shall e ngage cons ultants, as may be ncce ssary. 10 provide professional in spec ti on un iI limely basis. The permittee shall ac t ;IS a coorclin:lt or between lh c COllsuIWIHS. lhc co ntrac tor
Associallon of Slnu:1 111',)1 Enq: n(~nrs of tile: Pillilpplll e~,
CHAPTER 1 - General 11equiremenls
official. In the event of changed conditions, the permittee shall be respo nsible for infonning the bui lding oflici nl of such change and shall provide revi sed plans for approval. 109.6.5 BUilding Official The building orfi cial shall inspect Ihe projeci at the
vario us stilges of work requiri ng approviJl to detc rmine ndequate cOl1 lrol is being exercised by Ihe professional co nsultants. {h
109.6 .6 NOlilicalion of No ncompliance
If, in the course of fuHilJing their respcctive duties under thi s chapter, the civil engineer or the geotech ni cal engineer rind s that the work is not being done in confo nnance with thi s chapter or the appro ved,., gradin g plans, the disc repanc ies shall be reported immediately in writ ing to the permittee and to the building offi cial. 109.6.7 T r ansfer of Rcsponsibilily If the civil engineer or the geotechnical engineer-ofrecord is changed during grading, {he work shall be stopped ulllil the replace me nl has i.lgreed in writing to accept their responsi bility within (he area of techni cal co mpetellce for approval upo n completi on of the work. It shall be the duly of th e pennittee to notify the building official in wl;ting of such Change prio r \0 the. recolnmeJ)cement of such grading.
tests, other substamiatin g data, and com ments all any changes made during grading and thei r effect on the recomrncndmions made in th e approved geotechni cal engineering investigati on report. GeotcdUl ical engincers shall submit a statement that, to the besl of their knowledge. the work wi thin their aren of responsibilities is in accord ance wit h (he approved geotechni cal engineering repon and applicable provisions of thi s sec tion. 3. The gradi ng conl ractor shall submit in a fNIll prescribed by the building official a slmemCI, i of co nfonnance to said as-buill plan and .he speci ficati ons.
109.7.2 Nolification of Complel ioll The permi ttee shall notify the building official when the grading operati on is ready fo r final inspec tion. '; n:-li permission by the bui lding official shall not be giver .!" ' all work, including installation of all drainage f ? ! .md their protecti ve devices. and all erosion ~' measu res have been com pleted in accordance W I·': 1;:'_ final approved gnlding plan , and the requi red fep(l: ! been submitted by the engi neer-or-record.
109.7 Compleli on of Work 109.7.1 Final Reporls Upon completion or the rough grading work and 31 the final completion of the work , the following reports and
dnlwings and sup ple ments thereto
An ns-built gradin g plan prepared by the civi l e ng inee r retained to provide slich services in accordance with Section J09.6.5 showing original ground surfac e elevati ons, as-graded ground su rface elevations, lot drai nage patterns, and the loca tions and elevati ons of surface dmin age faci lities and of the ou tlets of subsu rface drains. As-constnlcted locations, elevations and details of subsu rface drains shall be shown as repo rted by th e geo tedlllical e ngineer. Civil engineers shall stale Ihal 10 Ihe bes t of their knowledge th e wo rk within the ir area of res ponsi bili ty was done in acco rd ance wit h the finil l approved grading plan .
2.
1\ repol1 prepared hy the geotec hnical engineer retained 10 provide such services ill accordance wi th
1-2 1
Sec tion 109.6.3 , including locations and elevations of fie ld density tests, summaries of field .Ind I;.lboratory
Nationa( Stru ctural Co(Je of t!1P. r.l11i1ippines (,111 Edition Volume 1
Association or Struc tural E 119inecrs of the Philippinp.s
NSCP C101 · 10
Chapter 2 MINIMUM DE5.IGN LOADS NATIONAL STRUCTURAL. CODE OF THE PHILIPPINES VOLUME I BUILDINGS, TOWERS AND OTHER VERTICAL STRUCTURES SIXTH EDITION
Association of Structu ra l Engi neers of the Philippines Suite 7 13, Fut ure Point Plaza Co ndo minium I I I2 Pan ay Avenu e, Q uezo n City, Phili ppines 11 00 Tel. No : (+632) 4 10-0483 Fax No .: (+632) 4 11 -8606 Email: !'!~10 ll l illc~com
Wehsil e: htt p://www.asc ponlin e.org
Nalloll
hilipPlnes 6 ' Edition Volume 1 i1
CHA PT ER 2 - Minimum Design loads
2· 1
Table of Contents CHAPTER 2 MINIM UM DESIGN LOADS ................ .. .................................... ........ ............................................................ 3 SECTION 201 GENERAL. ............................................................................................................. ................................... ...... 3 20 1. 1 Scope ... .....
....... .... ...
......... .....
. .......... .... ..
.. ........ ......... 3
SECTION 202 DEFINITIONS ........... ............... ..... ................ ...................................... ........................................................... 3 202. 1 Walls ...................... ..
...... 4
SECTION 203 COMBINATIONS OF LOADS ..................................................................................................................... 5 203. 1 General ............ ...... ..... .....
.............. ................ ....... ........... .. ................ ....... ..........
. .................................................. 5
203.2 SYlllbols and Notations. ......... ................. ................................ .......... ............................................. 5 203.3 Load Combinations llsing Strength Design or Load and Resistan ce Factor Design . .. ........ .......... ....... .. ..... ".5 203 .4 Load Co mbinati ons Using Allowable Stress Design ......... .. ........ ........ .......... ........ .. ......... ........................... 5 203.5 Specia l Seis mi c Load Combinations
.... ............ .....
........ ...........
. .... 6
SECTION 204 DEAD LOADS ........ .............................................. ........................ .................................................................. 9 . 204. 1 General .... .... .............. ................... .. .... .......... 204.2 Weigh ts of Materi,ds and Conslnlclions.. ........ .. .............. .. 204.3 Parlitio n Loads.. ........ ..................... . ................ .
..................... .. .... ............ ............. .... ..... ............ 9 .......... ....... ..... ................ .................................... 9 .. ............. 9
SECTION 205 LIVE LOADS ........................... ................. ......................................... ................ ............................................. 9 205. 1 Gen eral...... . .. ........... ..... ..... .. .. ... .... ...... .... .... .. .......... .... .. ............ ...... 9 205.2 Critica l DistributiOJl o f Live Loads.. .. ....................... .. .................. 9 205.3 Floor Li ve Lo ads ............. . ................. .. ................................. 9 205 .4 Roof Live Loads .......... ...... ............... ..... ........... ..... ............. .................................. .................................................. 13 205.5 Redl!ction of Li ve Loads .................................... ................... . ...... ........................ 14 205.6 A ItCrlHl tc Floor Live Load Reduc lion .. .. .... 14
SECTION 206 OTHER MINIMUM LOADS ............... ..................... ........................... ........... ............................................ 15 206. I Gelle ra l .... .......... .... . 206.2 2063 206.4 206.5
Olher Load s. I mpaci Loads
................. . Anchorage of Conc rete iln d Masonry Wall s ....... Interi o r Walt Lo ads..... .. ............. .. ..
206.6 Retaining Vo.' alJs ................. ........................... " ................... . 206.7 Waler Accumul at ion .. . 206.8 Up lift on Floors and Foundations . .......... ........ .. 206.9 Crane Loads ...... .. ....... . . ..... ... ...... .. ... . 206. 10 Heliport '!!lei Hel isto p Landin g Areas . ............ ..
. 15 .. .... 15 15 15 15 . 15 .. ...... .. 15 .. .. 15
. ......... .. ........ ......... ....... ........ ....... .. ...... ... .... ....... ... .... ..... .... 16 ... 16
SECTION 207 WIN]) LOADS ........ ....................... ................... ............. ............................................................................... 17 207. 1 Gene ral .................... .. 207.2 Definitions 2073 Symbol s and NOI.uiolls .. 207.4 Method I - Simpl i fi ed Pmct~d1ll'c .. . 207.5 Method 2 -- Analyti ca l Procedure .. 207.0 Method 3 ... Wind Tunnel Proced ure .. 207.7 GUSI Effect Fac tor for Other Struclures .. . 207.X ES lim'ilcs of D yn'lInil' PropcI1ics .............. ...... .. 207.9 Con sc nslis Sta nd 'Ir<.Is il nd Olher RcfcrclH.:cd i)(lClIIllCIH.'i .....
..................... ... 17 .. .... . 17
.. 19 .. .... 20 .. .... 2 1
... 01
.. ............................... :l2 .. .. 32 .. ...... .. ................ .................... 34
SECTION 208 ICAHTHQUAKE LOAI)S .............................. ....... .. ........................ ...... ... ...... .... .. ..... ......... .... .................. ... .. 72
2·2
C HAPTt:f~
2 -. Minimum Design Loads
208. 1 Geneml. ........... .............. .. .................................................. ..................................... .................................................. 72 208.2 Dcllnitions . ...... .... ..... ....... ...... . .... 72 208.3 Symbol s and Notation ...... .. ....... ......... .... ..... .. 74 208.4 Criteria Selecti on ........ .................. .. ................ ............................ ............................. 75 208.5 Minimum Design Lateral Forces and Rcl3lcd Effects ........ ................................. ....................................................... 81 208.6 Dynal1\ ic Analysis Procedu res ...................... .... ........ ... .............. .......... ..................... ..... ...... .................. .. ...... 90 208.7 Lateral Force 011 Elemen ts of Stnlctures, NonslJ1lctur.1I Componcllt,<; and Eq uipmcn t Suppol1cd by St ructures ... 92 208.8 Detailed Systems Design Requirements.. ....... ....... ...... . .. ..... ........ .. ... ..... 96 20R.9 NO ll-Bu ilding Stru ctures ........................... .. .. , ..... ... ...... ..... ". ,." .. ,.. ,.... '.. ,........ ,... .." ......... " ... 99 208.10 Si te Cntcgorization Procedure.,.,............ ........... ,., ,......... ,.......... ..................... ,............. , 101 208.1 t Alternativc Earthquake Load Procedure "" .. "." ................ ..... ,." ....... ,.102
SECTION 209 SOIL LATERAL LOADS ................................................ ...................... ................................................. ... 103 209.1 Ge nera!... ..
....... 103
SECTIO N 210 RAI N LOADS .......................................................................... ... ..... ................. .......................................... 111
I !
I
210.1 Roof Drainage ..... ..... ... 2 10,2 Design Rain Loads ..... , 2 ] 0.3 Ponding Instabili ty 210.4 Controlled Drailwgc
........... .......... ................. III ..................... ........ 111 ...... .. 111 ......... 111
SECTION 211 FLOOD LOADS ............. ....................................... ...................................................................................... 111 211. 1 Ge neral.. . 2 J 1.2 Definitions, 21 1.3 Establishme nt of Flood Hazard Areas, . , 2 11.4 DeSign and Constructioll ........ 2 1 1.5 Flood Hazard Documentation
Association of Structu ral
...... .......... ........... 111 ......... .... 111 .. ..... ..... .. ....... 11 2
.............. ... . ....... . 11 2 ............................. ........................... ...... 113
En~inep.rs
of tile PhilippInes
CHAPTEli 2 - Minimum DeSign Loads
2-3
The following terms are defined for use in this chapter:
ACCESS FLOOR SYSTEM is an assembly consisting of panels mounted on pedestals to pr9vide an under-floor
201.1 Scope This chapter provides minimum design load requirements for the design of buildings, towers and other vertical structures. Loads and appropriate load combinations, which have been developed to be used together, for strength design and al!owa~le stress design are set forth.
space for the installations of mechanical, electrical, communications or similar systems or to serve as an air-supply or return-air plenum.
AGRICULTURAL BUILDING is a stmeture designed and constructed to house farm implements, hay, grain, poultry, Ii vestock or other horticultural products. The stmcture shall not be a place of human habitation or a place of employment where agricultural products are processed, treated, or packaged, nor shall it be a place
used by the public_
ALLOWABLE STRESS DESIGN is a method of proportioning and designing structural members such that elastically computed stresses produced in the members by nominal loads do not exceed specified allowable stresses (also called working stress design).
ASSEMBLY BUILDING is a building or portion of a building for such worship, awaiting
for the gathering together of 50 or more persons pUfl)oses as deliberation, education, instruction, entertainment, amusement, drinking or dining, or transportation.
AWNING is an architectural projection that provides weather protection, identity or decoration and is wholly supported by the building to which it is attached.
BALCONY, EXTERIOR, is an exterior floor system projecting from and supported by a structure without additional independent supports.
DEAD LOADS consist of the weight of all materials ancl fixed equipment incorporated into the building or other structure. DECK is an exterior floor system supported on at least two opposing sides by an adjacent structure anci/or posts, piers, or other independent supports.
ESSENTIAL FACILITIES arc buildings. towers and other vertical structures that arc intended to remain operational in the event of extreme environmental loading from wind or earthquakes.
FACTORED LOAD is the product of a load specified in Sections 204 through 208 and a load factoL See Section 203.3 for combinations of factored loads.
th
National Structural Code of the Philippines 6 Edition Volurne 1
2·4
CHAPTER 2 - Minimum Design Loads
GA RAG E is a building or portion thereof in which motor vehicle containing flammable or combusHble liquids or gas in its tank is stored, repai red or kept.
2.
Any masonry or concrete walt that supports m ore than 2.90 kN/m of vertical load in addition to its Own weigh!.
GARA GE, PRIVATE, is a bu ilding or a portio n of a building, not more than 90 111 2 in area, in which only motor vehicles used by the tenants of the building or buil din gs on lhe premises are kepi or stored.
EXTERIOR WALL is any wa ll or elemen t of a wall, Or any membcr or group of members , that defines th e exterior bound aries or courts of a build in g an d that has a slope of 60 degrees or greutcr with th e horizontul plane.
LIMIT STATE is a condit ion beyond whicJ; i\ structure or member becomes unfi t for service and is judged to be
NONBEARIN G WALL is any wall thaI is not a bearin g wall.
no longer useful for its intended func tion (serviceability limit state) or
(0
be unsafe (strength limit state).
LI VE L O ADS are those loads produced by the use and occupancy of the building or Olher structure and do nOl include dead load, construction load. or environmental loads suc h as wind load, earthquake load and nuid load.
PARAPET W AL L is Ihat part of any wall entirely above Ihe roof linc. RETA INING WALL is a wall designed to resist the lateral displacement of soil or other materials.
LOADS are forces or other actions that result from the weight of all bu ilding materials. occupants and their possess ions. environmental effects. differential movements, and restrained dimensional changes. Penn ancnt loads are those load s in which variations over lime are rare or o f small magnitud e. All other loads are vari able load,. LOAD A ND RES ISTAN CE F ACTOR DES IGN (LRF D) M ETHOD is a me thod of proportioning and designing structural elements using load and resistance factors such that no applicable limit state is reached when the struc ture is subjected 10 all a ppropriate load combinations. The term "LRFO" is used in the design of sleel stru ctures. MA RQ UEE is a permanent roofed stru cture attac hed to and supported by Ihe buildi ng and projecting over public right-of-way. O CC UPANCY is the purpose for th at a bu ilding, or part the reof, is used or intended to be used . STR E NG TH DESIGN is a method of proportioning and designing stnlctural members such that the computed forces produced in the members by the factored load do not exceed the member design strength . The term strength design is used in the design of co nc rete stnlclllres. 202. 1 Wa lls B EA RI NG WALL is any wall meeting either of the following class i fications:
I.
Any metal or wood stud wall that slipports more thall 1.45 kN/1ll of ·ven ical load in addition to its own weigh!.
Associa tion of Structural Engineers of the Philippine s
CHAPTE R 2 - Minimum Design Loads
2-5
0.9 D+ 1.6 IV + J.6H
(203-6)
O.9D+1.0E+1.6H
(203-7)
whe re:
203.1 General Buildings. towers and other vertical SUl lctu rcs and <'\11 portions thereo f shall be designed to resisl the load co mbinations speci fi ed in Section 203.3 O[ 203.4 and, where required by Section 208, or Chapter 4 and the special seismic load combinations of Secti on 203.5. T he most critica l effec l ca n occ ur whe n o ll e or more o f lhe contribut ing loads 3rc not ac ting . All appli cab le loads sha ll be considered. includin g both eanhquake and wind, in accord ance with the spec ified load co mbin ations.
f,
= 1.0 ror fl oors in pl aces of publi c assembl y. ror li ve load s in excess,of 4 .8 kPa, and for garage live load
= 0.5 ror olher live loads
203.3.2 Other Loads Where P is to be consi dered in des ign, {he applica ble load shall be added lo Seclio n 203.3. 1 ractored as 1.21'.
203.2 Symbols and Notations D = dead load £ = eart hqu ake load sel rorth in Section 208.5. 1 Em = estimated maximum earthquake force that ca n be de veloped in the structure as sel fort h in Sec ti o n
208.5. 1.1 F
= load du e lO Oui ds wil h well-d e r,ned press ures and
II
= load
maximum heights
due lO lat eral pressure of so il and water in soil L = live load , except roof live load , incl udin g any permitted li ve load reducti on Lr = roof live lond , including a ny permitted li ve load reducti on I' = pondi ng load R rain load on thc undef1ec(cd roo f r = selr-straining fo rce and e rrects arising rrom cont raction or ex pansion resulting from tcmpcrarurc cha nge. shrinkage. llloislU rc cha nge. c reep in componelll materials, movement due 10 di ffe re nt ial scttl ement . o r comb inations thcreof . IV = load due (Q wi nd pressure
=
203.4 Load Combinations Using Allowable Stress Design
203.4.1 Basic Load Combinations W here all owable stress design (working stress des ign) is used. structures and all portio ns thereof shall resist the rnos t critical effects res ulting from th e foll owing co mbinations of loads: .
V+F
(203-8)
D+H+F+L +T
(203-9)
D + Ii + F + (L,o,. 1/) D+ N + F +0.75[L+ T
(2OJ-2)
1.2D + 1.6(L, 0 '- R) ... ([, Lo,- O.8W)
(203 -3)
1.2 V + 1.6IV + J,L+O.5( L, 0,-11)
(203-4 )
1.2D+ I. OE+/i L
(203 -5 )
(203-1 1)
(203- 12)
No increase in a llowab le stresses shall be used wi lh these load co mbinati ons except as specifica ll y permitlcd by Secli on 203.4.2.
Where load and rcsi.'itancc fac tor des ig n is ll sed, stru c tures :md a ll portions thereof sha ll resist the most c riti ca l erfects rrom the fo ll uw ing co mbinati o ns of factored loads:
1.2(V + F + r)+ 1.6(L + H)+ O.S(L,o,-ll)
(L,or R)]
1.4
203.3.1 Basic Load Combinations
(203 -1 )
·1·
D + N+ F+ (II' o r E)
203.3 Load Combinations using Strength Design or Load and Resistance Factor Design
IA(V+ F)
(203- 10)
N"_1IiOrlcJI Structural Code of tile Philippine s 6
th
Edition Volume 1
2·6
CHAPTER 2 .- Minimum Design Loads
203.4.2 AHernate "asic Loa d Combinations
In lieu of (he basic load combinations specifi ed in Section 203.4. I , stJ1J ctllrcs and portions thereof shall be permitted to be designed for the most critical effects resulting from the following load combinations. When using these all emalc basic load combinations, a one·third increase shall be permitted in all owable stresses ror all combinations, including W or E. f)
<-II
+F +075[ L+ L, +(W or I/~: J]
O.60D+W+H O.60 D + -
E
(203- 13) (203- 14)
+H
. (203 -1 5)
1.4
D + L + L,(or R)
(203- 16)
D+ L+W
(203 -1 7)
D + L+
E
(203·18)
1.4
203.4.3 Ot her Loads Where r is to be considered ill design, eac h app li cable lo ad shall be added to th e co mbin ati ons s pec ifi ed in See, io ns 203.4.1 and 203.4 .2. 203.5 Special Seismic Load Combinations
For both allowable stress design and strength des ign, the following spec ial load combinations for seismic desi gn s hall be used as speci fi call y required by Secti on 208, or by Chap,ets 3 ,hro ugh 7.
1.2D+/,L+ I .OE",
(203- 19)
0.9D± I.OE",
(203·20)
wh ere:
I,
:::
1.0 for noors iii placcs of pu blic assembl y. for live loads in excess of 4.8 kP
Association of Structurfl ! Engineers of the Philippines
CHAPTER 2 - Minimum Design Loads
2-7
Table 204- 1 Mi nimum Densities for Design Loads fro m Materials (kN/m3) Ma terial
Density
Alumi num DilUllunous Products Asphaltum Graphite " Paraffin ........ ,........... .
26.7
Material
Densit y
Lead .................................. .
IIL5
Lime
PelroJeum, crude
Petroleum. refined.
Petroleum. benzine ...... . Petroleum, gasoline Pitch ................. . Tar
Brass Bronze ..... Cas(~slone masonry (cement. slone, sand) Cement, port land, loose .......................................................... . Ceramic tile . ........................................... .
Charcoal ...................... . Cinder fin ................................. Cinders, dry, in bulk .................................................... .
8.8 8.6 7.9 7.2 6.6 10.8 11 .8 82.6 86.7 22.6 14.1
23.6 1.9
9.0 7.1
Coal Anthracite, piled Bituminous, piled Ligni te. piled PCilt, dry. piled ...
8.2 7.4 7.4 3.6
Concrete. Plain Cinder ........ .... ... ...
17.0 15.7 Haydi te (bumed-clay aggregate) ......... ....... ................. ..... \4 .1 Slag ................. . 20.7 SlOne 22.6 Vermiculi te and perlite Ilggrcgalc. nonload- bcaring ... 3.9-7.9 Other lighl aggregate. load bearing .11.0- 16.5
Expanded-s lag aggregate
Concrctc. Reinforced
21.2 27.2 22.6
Masonry. Brick Hard (low absorption) Medium (medium absorption) Soft (high absorption) ......... ...
20.4 18.1 I S.7
MASONRY. Conc rete (solid ponion) Lightweight un its Med ium weight units Normal weight uni ts ................... ...
21.2
Masonry grout
22.0
16.5 19.6
Masonry. Rubble Slone Granite Limestone. crysta lline Limestone. oolitic Marble ....... ........ ... ........ ... ............ .. ................... . Sandstone Mortar, cement or lime
24.0
23. 1 21.7 24 .5 21.5 20.4
7.1
Particle board Plywood
5.7
Riprap (nol nubmerged ) Li mesto ne
13.0 14.1
Sandstone
17.4
...................... _............................................... . 2 1.7 Slone. (including gra\lel) ............................. . 23.6 . ................................. ..... ....... . 87.3 2.2
Earth (nol subme rged) Clay. dry Clay. damp ..... . Clay and gravel. dry ........................ . Silt. moist. loose ... Silt. moist, packed Silt, flowing .... Sand and gra\le!. dry. loose _ Sand and gra\lel. dry. packed ........... _.... _............................. Sand and gravel. wet..
9.9 17.3 15.7 12.3 15. 1 17.0 15.7 17.3 18.9
Earth (sublncrgcd) Clay
12.6
Soi l ................. .. River mud S:lnd or ;,,1 "vel ......................... ................ . Sand o r gra\lel
11.0 14. 1
. ................................ .
I)A
10.2 25. 1 1603 11.0
7.9 9.0
14. 1
C lean and df)' River. dry ....................................... .
16.7
Slag Bank
11 .0
Bank scrccnings Machine Sand ..
17.0 15.1
8.2 27.0 77.3
Slate S teel. cold-drawn . Slone. Quarried. Piled Basalt. grani1e. gneiss ........... _................ . Limestone, marble. quartz Sandstone ... .......... ..................... ....... ...... . Shale Greenstone. hornblende TeCT3. COlla, Archi tectural Voids filled Voids unfilled
Tin
\5.1 14 .9
12.9 14.S
16.8 18.9
.... 11.3 72. 1
Water Fresh Sea
9.8 10. 1
Wood (see Table 6.2 for relative de nsities for Philippine wood )
Zinc, rolled !'iheel
Iron
Cast Wrought
25.9 25.9
Sand
Cinder .................................. .
Glass ... Gra\lel. dry .. Gypsum. loose GYPSUlll. w:ltlbu;Ird kc
7.1
Masonry. Ashlar Stone Granite Limestone. crystalline: Limestone. oolitic ........ _.. ....... .. Marble ... Sandstone .....
Slag
Copper . Cork. compresseiJ .......
5.0
Hydrated. k>ose ............... .................. .. Hydrated. compac1ed .................. ..
12.7 21.2
70.7 7.SA
tli
National Structural Code o f the PI1i lippines 6 Edition Volume 1
70.5
2-8
CHAPTER 2 - Minimurn Design Loads
Table 204-2 Minimum Design Dead Loads (kPa) (Use actual loads when available) Component
CEILINGS Acoustical Fiber Board
Load
FLOOR FILL 0.05
Gypsum Board (per mill
thickness)
0.008
Mechanical duct allowance ....... 0.20
Plaster on tile or concrete Plaster on wood lath
0.24 0.38
Suspended steel channel system
0.10 Suspended meta! lath and cement
plaster
0.72
Suspended metal lath and
gypsum plaster Wood fUITing suspension system
0,48
0.t2
COVERINGS, Roof and Wall Asphalt shingles ......................... 0.10 Cement tile .................................. 0.77 Clay tile (for mortar add 0,48 kPa) Book (ile, 50 mill ................... 0.57 Book tile, 75 flun .................. 0.96 Ludowici .. ................................ 0.48 Roolan... . .......................... 0.57 Spanish. .. ........................ 0.91 Composition: Three-ply ready roofing .......... 0.05 Four-ply fclt and gravel ........... O.26 Five-ply felt and gravel ........... 0.29 Copper or tin ............................ 0.05 Comlgated asbestos-cement roofing .................................... 0.19 Deck, metal 20 gage. . ............ 0.12 Deck, metal, 18 gage ................... 0.14 Fiberboard, 13 1llJ11 . . .......... 0.04 Gypsum sheathing, 13 mIll ......... 0.10 Insulation, roof boards (per mm thickness) Cellular glass 0.0013 0.0021 Fibrous glass 0.0028 Fiberboard Perlite 0.0015 0.0004 polystyrcne foam Urethane foam with skin 0.0009 Plywood (per mm thickness) 0.0060 Rigid Insulation, 13 mrn . 0.04 Skylight, metal frame, J 0 nun wirc glass 0.38
Slate,S
Illlll
Load
Component
0.34 0.48
Slate, 6 mm Waterproofing membranes: Bituminous, gravel-covered. 0.26 Bituminous, smooth surface .0.07 Liquid, applied ..................... 0.05 Single-ply, sheet ................... 0.03 Wood Sheathing (per mOl thickness) ............................ 0.0057 Wood Shingles ........................... 0.14
FRAME WALLS
Cinder concrete, per mill .......... 0.017 Lightweight concrete, pcr mm .0.015 Sand, per mm ........................ 0.015 Stone concrete, per mm ............ 0.023
FLOOR AND FLOOR FINISHES Asphalt block (50 rnm), 13 mill mortar ... .. .......... 1.44 Cement finish (25 mm) on stoneconcrete fil!.. .. ................ 1.53 Ceramic or quarry tile (20 mm) on 13 mill mortar bed ............. 0.77 Ceramic or quarry tile (20 mm) on 25 mm 111011ar bed ............. 1.1 0 Concrete fill finish (per mm thickncss) .............................. 0.023 Hardwood flooring, 22 rnrn ........ 0.19 Linoleum or aspbalt tiie, 6mm ... 0.05 Marble and mOJ1ar on stoneconcrete fill ............................. 1.58 Slate (per mm thickness) .......... 0.028 Solid Oat tile on 25 mm mortar base.. . .......................... 1.10 Subflooring, 19 mill ................... 0.14 Terrazzo (38 mm) directly on slab.. .. ................................ 0.91 Terrazzos (25 mm) on stoneconcrete fill ............................ !.53 TClTilzZO (25 mm), 50 Illm stone concrete.. ...1.53 Wood block (76 mm) on mastic, no fill.. .................. 0.48 Wood block (76 mm) 011 J3 rnm mortar base ........ ............. ...... 0.77
FLOORS, WOOD-JOIST (no plaster)
- - - - _ .......
~gist SpacinE
300 .
' 4(JtJ"-' . 6tJtJ"
(mm)
mm
; .:
mm
0.25
- -.----.~~-.-,
.. ---
0.30 i 0.30 1.50x200 50x250 i IUS ·.r:o..3i>~-l .1..
50x300
0.40
0.35
Exterior stud walls:
SOx I (X)
mm 0.25
0.25 0.30 0.30
FRAME PARTITIONS Movable steel partitions ... 0.19 Wood or steel studs, ! 3 mill gypsum board each side.. . 0.38 Wood studs, 50 x 100, unplastcred 0.19 Wood studs 50 x 100, plastered one side.. .. .......................... 0.57 Wood studs 50 x 100, plastered two side ... ··· .. ···· ...................... 0.96
Association of Structural Engineers of the Philippines
mill @
400 mm, IS-1l11ll
gypsum, insulated, 10-mm siding ................................. 0.53 SOx 150 mOl @ 400 mm, I5·mlll gypsum, insulated, 10-mm siding ....................... 0.57 Exterior ~tlld wall with brick veneer 2.30 Windows, glass, frame and sash 0.38 Clay brick wythes:
IOOmm
1.87 3.80 5.50 7.42 CONCRETE MASONRY UNITS 200mm 300 mill 400mm
Hollow Concrete Masonry units (Unplastered, add 0.24 kPa for each face plastered) Grout : Wythe thickness (mm) Spacing : 100 ; 150 200 · 1_6.5 kN/m, Density o( Un!t
-,
Nog'ou;
CijJj'I.15 ,
800
1.40 . 1.53 1.63
6oii ' .. "--'i:so"
148 . 2:6 i
22rj'
400 .......... !~J2rJ 192-1254 " Full '2.50 ,2.63 '359'
!Y..~~~/~11.l.}2~.r"\_~.i~X.?r Un it
· !'J.O.g~(?l~1
1.24 1.59 1.69 1.98 2.69
800 600 . 400
Full
Joist Sizes
50xl50 .1..i 0.30
Load
Component
r.---"'~'
Full
. 2:44 . . 282 . 3:88
r '1;8~ : : L. 2.39
1.83 .. L 1.96 2.13 2.2 . r 2.84 " 2.97!
600!
, ..
172 . 2.25
1.87 2.11 2.82
21.2 .k.r~.r~ny. _p~,~~,i.tX(}r~J[.lJt !'l_ogr."Ol!t '1 .J.}? __ . 1.44 ·?99. I. _ }}1_..! 1.82
400
.....
1.34 I. 72
259
292 . 3:97 .
CHAPTER 2 -. Minimum Design Loads
2·9
204.1 General
205.1 General
Dead loads consist of the weight of all materials of construction incorporated into the building or olher struclUrc. including bUI not limited to walls, floors, roofs. ceilings. stairways, buill-in partiti ons. finishes, cladding and other similarly incorporated architectural and stmcLUrill items, and fixed se rvice equipm ent, including the weight of cmlles.
Live loads shall be the maximum loads expected by the intended use or occupancy but in no case shall be less than the loads required by thi s section.
204.2 Weights of Materials and Constructions
The actual weights of materials and constructions shall be: used in determining dead loads for purposes of design. In the absence of definite illfonnation, it shall be permitted to use the minimum values in Tables 204-1 and 204-2 . 204.3 Partition Loads
Floors in office buildings and other buildings where partition locations arc subject to change shall be designed 10 suppon, in add ition to all otiter loads, a uniform ly distributed dead load equal to 1.0 kPa of floor area.
205.2 Critical Distribution of Live Loads Where structural members are arranged continuity, members shall be designed using conditi ons, which would cause maximum bending moments. Tbis requirement may tic accordance with the provisions of Section 205.4.2, where applicable.
to create the loading shear and satisfied in 205.3.2 or
205.3 rloor Live Loads 205.3.1 General floors shall be designed for Ihe unit live loads as set forth in Table 205·1. These loads shall be taken as the minimum live loads of horizontal prOjection to be used in the design of buildings for the occupancies listed, and loads
Where it can be determined in designing fl oors that the actu al li ve load wi ll be grea ter (han {he value shown ill Table 205-1, the actual live load shall be used in the design of such buildings or ponions th ereof. Special provisions shaH be made for machine and apparatus loads. 205.3.2 Distribution of Uniform Floor Loads Where unifonn fl oor loads are i nvo l ved, consideration may be limited to fu ll dead load on all spans ill co mbination with full live load on adjHccllt spans and alternate spans. 205.3.3 Concentrated Loads Floors shall be designed to SU ppOrl safely the un iformly distributed li ve loads prescribed in this section or the co ncentrated load given in Table 205 ~ 1 whichever produces the greatest load effects. Unless otherwise specified the indica ted concentration slwll be assumed to be uniformly di stributed over an area 750 mill square and shall be located so as to produce the lIlOlximum load effects in the slruclUral mcmber. ProviSion shall be made ill areas where vehicles are used or stored for concentrated loads, L, co nsi sting or tw o or more loads spaced 1.5 III nomi na ll y on ce ntcr without uniform live loads. Each IO(ld shall be 40 percen t of the
National Structural CoeJe of the Pl1ilippine s 6\11 Edition Volum e 1
2-10
CHAloTER 2-- Minimum Desi(Jn Loads
accordance with Section 203.3 or 203.4 as appropriate, producing the greatest stresses shall govern.
gross weight of the maximum size vehicle to be accommodated. Parking garages for the storage of private or pleasure-type motor vehicles with no repair or refueling shall have a floor system designed for a
205.3.4 Special Loads Provision shall be made for the special vertical and lateral
concentrated load of not less than 9 kN acting on an area of 0.015 rn 2 without uniform live loads. The condition of concentrated or uniform live load, combined in
loads as set forth in Table 205-2.
Table 205-1 - Minimum Uniform and Concentrated Live Loads
Use
01'
Occupancy
Category
Description Office use
2.4
9.0'
. 4.8
9.0'
------------+------!--------I
1. Access floor systems
Computer use
0 7.2 2. Armories I--------------+----------i--------------·-·-------2.9 0 Fixed seats 3. Theaters, assembly areas J and auditoriums.
3.6
o o o o
1.9
1.3
Movable seats
4.8
Lobbies and platforms
4.8
Stages areas
7.2
4. Bowling alleys, poolrooms and similar recreational areas 5. Catwalk for maintenance access
- - - - 1 - - - - .---.--4
6. Cornices and marquees
3.6
7. Dining roOnls and restaurants
4.8
- - - - - - - - - - -..- .--.-.-----..- --.----.--.-----... --- _ . _--_._-----1---
o o
8. Exit facilities 5 4.8 ---------. - . - - - - - - - - - - + - - - - - - - - - - - - - - - - - .--..----.----11----.- .--..-----..---.General storage and/or repair 4.8 - . - -..---------.--.-- --.-.-.-...---------- '- - - - - - - - 1 9. Garages Private or pleasure-type 1110tor 1.9 -'-vc"I"'1i"'c.::lc'--,,5("'0o.ra'"g"'>c'-_ _
_____._._____________.____+___
+ __._________+____._._. ___. _.__ 1.9
Wards and rooms
I--;-;----:--,---;;--~-+------------
I O. Hospitals
Laboratories & operating
f-____~r..::o~o_"Ill.::S'- _______ . __.____
2.9 0 _.0 . _ _ •
."
• __
4.5 '
---------
Corridors above ground floor 3.8 - - - - - - -_._- --- -- - - - - - + - _ . _ - - - _ ._ _._--_.__._-_. _. _------_._._------ Reading rooms 2.9 1------·_--------_·_---- - - - - I I. Libraries 7.2 Stack roOIllS Corridors above ground floor
4.5 2
o~"'o_._~_~._. _. _______ _
4.5 _... _..._- - - -4.5
2
4.5 '
3.8
- - - - - - - - - - - - - - - - - - - - - - -----_·_------------1--- - - - - - .__._---------_._--9.0 2 Light 60 ·_··_·__·_·_·--·_·-1----12. Manufacturing ----------_.•.. _. ._ . _------- _.. _ - - - ' - - -
Heavy
Association of Structural Engineers of the Ptlilippines
12.0
13.4 2
CHAPTER 2 •. Minimum Design Loads
~
..,......... ,. ......
_.• -.....
Usc 01' Occupancy .._-- ..._'....... . _.... .. _- --- ._.,. ....... ...... Description ..,
...... ... . ... ..• .. ... . .,_ .. "-,, ....... '
Category
'
- .. _--
Uniform Load 1 .. .. -..,.---..-.... . .. ... -. kPa ~- - ,
Ca ll Ce llters & B PO
4.8
9.0
Orrices
2.4
9.0'
Building corridors above Brou nd floor
3.8
9.0
Press rooms
7.2
11.0 '
Composing and linotype rooms
4.8
Basic floor area
1.9
0'
Ex tcrior balcon ies
2.9'
0
Decks
1.9'
0
Storage
1.9
0
conidors
16. Rcs lroo ms
--
9
17. Reviewing sl
4.8
0
Same as area served or Occupancy
--
--
Cla ssrooms
1.9
45 '
Corridors above ground Ooor
3.8
45
Ground Ooor corridors
4.8
4.5
Public access
12.0
--
---_ _-_
20. Sidewalks a nd drive ways
Lig ht ---------.---_ Heavy
21. Storage
_---_._---- _..---------- --_.-
_-_
J
A'{:rt' lIIbly ar('os inc/llt/l' .mel! OCCllf)(III(·it',~ ar(' W"lI'mlly aC("/',\'.\·ihle to til{! flublie.
Il,t
,-,
-
..------
--
Retail
4.8
4.5 2
Wholesale
6.0
13.4 1
--
4.8
--
-
Nores fOR TMnE 205·/ See Scctioll 205.5 j(Jr live food reciuctiollJ. S('c S/'uil}ll 205.J.3.jint paragmph./or Ol"/'lIlI/ loud
7
12.0
..
..
22. Stores
21 Pedcstrian bridges and walkways
-
--
0.0
..
._---
--
-
--
18. Roof decks
19. Schools
--
.. _.....
9.0 '
--
-
~
kN 9 .0
13. Office
15. Rcsidelllial 8
Concentrated
-_ ........ _.•.Load _-- _... - .....
2 .9
------Lobbies & ground floor
14. Print ing plants
"
~
2·11
--
IIIJp/i(·/lti,lll.
dlllln' I/(//ls, Ilrill room.". Rymllfl.filllll.f. pla.l"~I"OIIIIl!.r. I'!(/Ul.~. /rrr(lc('s (Illd .I'ill/ifa l" occllpmlC'i('s that
F Ol" Jpe C"i{/('fmrf!(ls{~ rollfl'. sa Sectioll 205.-1.4, I:.:,ril/Clcilitie.l' .I-/W/l ill l"llldl' .\"I(ch 11X(',t (/lui .I·imilt,,· lur .(.
(I,t /'rIITidol".\' .I'en'ill}; lII/I/I '("/ I{lfll1I
load 0/ I() o/" morc " cr.tll lI s. c.l'IcriOI' exit baIroil ii'S, ,I/(/irll'(IJ'J, fin'
('$((1/)(',1'
Im/il· idllal sll/il" tr('ml.l· sh/lll hi' des;gll(,(/ to .I·II/'/Io,--t a 1.3 /.;N ('oll('('l lll'(I(('d !lIad plw,(,(f in a posit;ulI thaI would rall.fl' /111J.rilllllll! .~/r('ss. Swir slri"I-It'r.f ilia)' hI' de.\"I);IU:,tl fin the ul/ijt".m IO(ld ofC'1/orJlI ill tilt' Ie/hit'. Stl~ 051'( '(;011 205 ..1.3•.f('c·oll(/,mmgraph, /tJf (,(lIIcctl/ml('d lom/.f. Srr
1'0"'1' 205·2 fi"'I'('hk/~ Im'-rier~.
RI'.\·irh!l/tin( o('n lp(ll/t·ir.f iI/dud., I'riwlIl! dwl'ifillg.f. (111(11"11111'111$ lilli' hOld guest 1"/10111.1'. Rrs/rllfJl/I
/(lOc/.f sllall 1101 Ill:
/f'.1.{
IlIml Ihe' load for 111(' ocne{l(lIIcy wil h whl<__"
National S truc tural CorJe or
(I'le
U1
flu.'.\' (In' tI.l·sm ;a(('(I. but /l~('d 1/tIi c.n,:(,l'l/ 2.4 kP(I .
Philippinos G Edition Volume 1
2-12
CHAPTEli 2. ... Minimum Design Loads
NOlexfor Table 205-2
Table 205-2 Special Loads'
1
Vertical Latera! _+_--"L",o:"""d__-i-._}__o_"_d__
Usc or Occupancy
___C_ -a_tc-,g,-o_r'-Y___ j ___ ~~~criJ!_I._i(_"_'_I___k_P_"_-----j __.-.:k.-.:-P-,-a'---j I.
Construction,
Walkway
-
public access al site (live load)
-
-
2
~----.-
---------_._-
Docs flOlllPI)!.\' 10 cl'ilings thm hlll'{' ,wjfid('1JI tlJlIll (len'.I's ji'OIII be/ow. ,I'l/ch llial o('n'ss is 1101 rt'qllircd lI'ililin Ihe sllIln' a/Jo\'!! (he cciling. 00('.\' no( IIpply II! Ct'iliIJg.l· if (he IIl1ic areos ohm'!' fhe cd/ing {Ire 1101 pr(Jllidei/ with access. This hl'e loud IIt'NjIlO( IN' considered (/.1' w:lillg simu/wl/collsly lI'ilh other lil'(, /(JUd.I' imposed UpOIl (Iu' ailillg framing or ils supporting s(rw'IJ/J'{'.
7.2
I-~-----------··-~~I-----I~---+----j
2.
(3randstan(:s,
reviewing, stands bleachers, and folding and
telescoping
Seals and footboards
1.75
Catwalks
1.9
Sa Note 3
,j
seating (live load) 3.
Stage accessories (live
Follow~p;t:-·-
load)
---.--..
---.-.~
._----.-
projection and
Over stages
Ceiling framing (live load)
1.0
All uses
supporting the.~e rails. 7 A load per lincal ml'ter (kNIIII) /() be applicd horizontally at right
0.5 <1
except over . stages ._"_ ... _____ ..,_.
5.
(lllgk~ 10
Partitions and
0.25 interior walls, 1~6-.~E-'-~'l-'-c-'-va-'-t-'-o-rs-'-'-'-In-'-d:""'-+~~------ ~-·----·---·-I-~~--i dumbwaiters (dead and live ~____~I(~"~II~ls~)____~
2 x total loads
-·--·-ro-t;-I-Io-ad--~"~~~~~j-~~~
7.
Cranes (dead
including impact
and live loads)
1,25 x IOlal load'\
increase ----------':xit fac;ii!T~s
serving an greater than Balcony railings
and guardrails
(1.I 0
x
total loado
0.75 kN/m
occupant load
B.
The impact jacfOrs included arl' Jor cram's with .,'ted lI'ilee/.I' riding Oil ,wed rails, TIJ<'y ilia), be modified if SlIbsf(lntilllillg {ecllnical data accepwble 10 fhe bllildillg official ix SlIlimilled. Live loads Oil crt/ne support Rirders omi Iheir COlll1ectiollS shall
he taken as the lIJaximllll! ('/'{IIIC wheel loads, For IH'IU/OIII operated traw'fing crane support girders olld their cOllnectiollS, rhe imp(/ctJactors shall be I. JO. nJis applies in the ilifl'Clioll parallel to (hl' rullway mils {longitudinal}. The jaclor Jor Jorces p<'Ipelldiclilaf 10 Ihe mil is 0.20 x Ihe 11'(II/SI'('I'se Iml'eling IO(lds (trolley, cab, /looks olld IIIfI'd loads). Forccs shall be appfi{'d (If lOp oj rail (llld lIIay be disturbed omong rails of mllllip/1' rail C/,{lIIe,~ and shall he dislrilmted with duc regard for latNal s(if/tI('SS of (hc Sll'IIctllres
2.4 i___________ I-'c~~.~
4.
(Jnils is kNlm. /..tl/{'rol .\'\\'0)' I){(/I'illg loads of 350 Nlm {Jarallel (Ill/I 145 Nlm perpendiclIl(lr.I' 10 sl'a( (lnd jO{)(/)ow
7.2
Canopy
nJe tabulated loods orl' minimlllll /i)(Jds. Where olher ver/iml by Ihis code or reqllired hy thl' design would ((JUSI' gn'(l/er Slre.I'.\'<'S, Ihey slwll be used. Loads are ill kPo linkss ()/h('l'll'isl' illdiclIl{'d in Ihe rab/I'.
S
righl (lllglcs 01'1'/' Iht' entire triblltal), area. ille/llding openings alld spaces helween rails. Reaclioll.\' du£' 10 Ihis loading /lccd nol be combined with those oj Footnotc 7. v A horizontal load in kN applied (If right (lngh's /(J Ihl' I'I'hic1t~ barrier (If a heifilll of 450 1/1/11 (I/;m'e rhe parking surfllC!'. The jorce may be di.Hriiulfed (11'1'1' a 300-111I1I',Wf/lare orca, In
kN/m
Components
!.28
0.30 7
The 111OllIJtillg : oj handrails .1'1/(/11 be such that the complcted handrail (lnd slIpportillg strU('llIn' art' cupabh' (~( \\'i(hs/(Iliding a load oj (J[ least 890 N applied ill alii' directioll 1It aNI' {loill( 0/1 Ihl' fail, Tln's(' loads s/Jal! nol /)(' (/.~'.\'lmJ('d to (lC( ('lIlIlI/lmiH'I\' with Itcm 9. \/(~l'Iiclll membas oj stora[ie /'(Icks ,I'hal! hc prol('c/ed from impact Jorces (!( opef(llill[i equip/llelil. or rocks shal! 1)(' designed so that fiji/un' (!( 0111' l'erticalll!(,lIIber \l'il/llot CO lise cof/opse oj 1/101'1' 1/)0/1 tile bny or !J(/ys dircctly supported hy Iha/lIJember.
7
50 1-=----1----1--·_··_--
Other than exit facilities
fhl' fOp rail.
Intermediate rails, panel fillers (lnd thl'ir CO/lnectiolls shall be capable OJWifhstaliding (j load oj 1.2 kP(I applied horizonta!!.,· al
il
Thl' 1.1 kN load is to be applied to (111.1' single fire sprillkler support poillt hilt flOl simult(llu'OI(.\'/Y to 01/ ,\'II/>porl joillts.
f-------.------- 9.
Vehicle barriers
10.
J-landrails
! J. Storage racks
27 kN' S('l' Noll' I()
Over 2.4
high
III
Total
loads"
12. Fire sprinkler
1.1 kN plus
stnJctural support
water-filled
----- -- - -
weight of
See Note 10 See Table 208-/2 See Tahfe
Ii 208-/2 _. _______i.~~~c____"_______ _
Association of Structural Engineers of Ole Philippines
CHAPTER 2 - Minimum Design loads
Table 205-3 Minimum Roof Live Loads
2·13
I
,.---- -- _ . _ - - - METHOD I
ROOF SLOPE
-
o
Tributary Area (m') to 20 20 to 60 lOver 60 Uniform Load (kPa)
I. Flat J or rise less than 4 units vcnidb.l in 12 ullit s horizontal (33.3% slope). Arch and dome with rise less than one-eighth of span. 10 less than 12 units vertical in 12 unit s horizontal (33.3% to less than 100% slope). Arch and dome wi th rise one-cig})!h of span 10 less than
METHOD 2
Uniform Load 2 (k Pa)
Rate of Reduction , r
Maximum Reduction
R (percen tage)
1.00
0.75
0_60
1.00
0 .08
40
0.75
0.70
0.60
0.75
0,06
25
0.60
0,60
0 .60
0 .60
0,25
0,25
0,25
025
2. Rise 4 units verti cal
three-eighths of span. 3. Ri se 12 units vertical in 12 units horizolllal (100% slope) and greater. Arch or dome with risc three-eig hths o f
span or greater. No reduction permifted
4. Awnings except cloth covered . "
-
----- ------- - ------ ------ ------,.,... ".
5, Greenhouses,
, J
J
l
lath agri cu ltural buildings . 5
houses
and
0,50
0.50
-- ---, 0.50
0,50
-
For sJ1ectnl'l'urpos~ mnf.f. -W't: Sl'ct/OII 205.4.4. 5u Sections 205,5 (1//(/ 205.6 for /it·f!·/ond reductions, Th(' rare (If "'dllC/ioll r ill EqullIi(lll 205·/ ,fh(1I1I)~ (IS ;lIdicatf'd ill Ih~ lobiC'. '/1". max;1I/lfm redllnion. R, s/ItIIIIl()Il'xcecd Ih ~ l'{l/lfC' illfJiI:nI('d ill the /OhI~. A fI(1I roof is (III)" mnj wil/) a slope le.n tlul/J 1/4 wlil I'erti, (I/ i ll 12 lill i/of Ir nrhmllll/ (2% slo!,e). The 1;1'(' /11(1(/ fllr filii raoff is ill (ldtiilinll /(J lilt J'rmdiIrg hKul required h.I' Sf'nim/ 206.7. SI'(' dl'jilll/imf it! S,·,·tioll 202. Sl'e SC'c/ifm 205.4.4.fllr , 'WII 'c'lllm/i'd load "('(Illiremenu .for lU'(>I,"hOlHC rool flU'wbers,
2()5.4 Roof Live Load s 205.4, I General Roofs shall be designed for the un;( live loads. L" set fonh in Table 205-3, The li ve loads shall be assumed to act vertically lipoll the area projected 011 a horizontal plane.
205.4.2 Distribution of Luads
Where uiliform roof loads arc involved in the design of $tructural Illcmbcr$ arranged to create continu ity, consideration may be limited to full dc,ld load$ 011 all spans in co mbination with full roof live loads on adjacent spans and on al ternate spans.
For th ose conditi ons where light ~g agc metal preformed structural .sheets serve as the SUpp0l1 and finish of roofs , roof slructum l members
A conccnlr
J,
Water <'lCculllulmioll as prescrihed in Section 206.7.
Exceptio'l: Altenzate spa~1 loading need flot be considered where the uniform roof live load is 1.0 kPa 'or more.
111
National Structural CO(j G of U18 PhiliPPUHJS 6 Edition VOIUI11e 1
2·14
CHAPTER 2 - Minimum Design l.oads
205.4.3 Unbalanced Loading Unbalanced loads shall be used where such loading will result in larger members or connections. Trusses and arches shall be designed to resist the stresses caused by unit live loads on one half of the span jf such loading
results in reverse stresses, or stresses greater in any portion than the stresses produced by the required unit live load on the entire span. For roofs whose structures arc composed of a stressed shell. framed or solid. wherein s tresses caused by any poim loading arc distributed throughou t the area of the shell, the requirements for unbalanced unit live load design l11<1y be reduced 50
The live load reduction shall not exceed ·m i' Ci,-'~: l4 t ;n garages for the storage of pri vate pleasure cars havius. a capaci ty of not more than nine passengers per veh icle. 205.6 Alternate Floor Live Load Reduction
As an alternate to Equ,Hion (205~ I ), the unil live loads set forth in Table 205~1 Illay be reduced in accordance wilh Equation 205·3 o~ any member, including Oat slabs, having an inOuence area of 40 m 1 or morc. (205-3)
percen!. where:
205.4.4 Special Roof Loads Roofs 10 be used for special purposes shall be designed for appropriale loads as approved by Ihe building official. Greenhouse roof bars, purlins and rafters shall be designed to carry a 0.45 kN concentrated load. LT. in addition to the uniform live load 205.5 Reduction of Live Loads The design live load determined using the IInit live loads as sel fMh in Table 205-1 for floors and Table 20S-}. Method 2, for roofs may be reduced 011 any member supporting more than 15 m2, including Oat slabs, except for floors in places of public assembly and for live loads greater than 4.8 kPa. in accordance wit h the following cqUl.ttion:
R = r(A -15)
(205-1 )
= influence area, 1112 = reduced design live load per square meler of area supponed by the member L" = unreduced design live load per square meter of area supponed by the member (Table 205-\) AI L
The influ ence area AI is four times the tributary area for a co lumn , two times the tributary area for a beam, equal to the panel area for a lW() ~ way slab, and equ al to the product of the span and th e full flange width for a precast T-beam The reduced live load s hall nOI be less Ihall 50 percell I of the unit live load La for members receiving load frolll one level only, nor less than 40 percent of the unit live load La for other members.
The reduction sha ll not exceed 40 percent for members re<.:eiving load from one level only, 60 percent for other mcmbers or R. as detemlined by (he following equation:
R=23. IO+DIL)
(205-2)
where:
A D L
R r
= area
of floor or roof supported by the member, square meter, m 2 = dead load per squ are meIer of area suppo rted by th e member. kPa = uni t live load per square meIer of area supported by the member. kPa = reduction in percentage, %. = rate of reduction equal to 0.08 for nOOni. Sec Table 205-3 for roofs
ror storage loads cx<.:eeding 4.8 kPa, 110 reduction shall bc Innde. except that design live loads on co lumns may he
reduced 20 perce nt.
Associa tion of S tru cturFlI Engineers of the Pllilippinf)S
CHAPTER 2 .. Minimum DeSIgn Loads
206.1 General JII addition to the olher design loads specified in this chapter. struC[UrC5 shall be designed to resist Ihe loads specified in thi s section and the special loads scI forth in Table 205 2. Sec Section 207 for design wind loads, and Section 208 for design earthquake loads. M
206.2 Other Loads Buildings and ot her slnlClures and pOri ions thereof shall be designed to resist ali loads d ue to app licable fluid press ures. F, lateral so il pressures, If. p ~ nding loads. P, and self-straining forces, T. Sec Seclion 206.7 fo r po nding loads for roofs .
2-15
206.5 Interior Wall Loads Interior walls, pcnnancn! partitions and temporary partitions that exceed I.S 111 in height shall be designed to resist all loads to which they are subjected but not less than a lo.ad, L , of 0.25 kPil applied perpendi cul ar to the wa ll s. The 0.25 kPa load need 1I0t be applied simultaneously with \vind or seismic loads. The defl ec tion of such walls under it load of 0.25 kPa shall not exceed 1/240 of the span fm walls with brittle finishes and IIl20 of the span for wall s with flexible finishes. SC,e Table 208-12 for earthquake design requirements where such requirements are more restricti ve. Excepti(J1J: ..,,'
Ffexible,' jdiding orpor1dki~par(iiioJ):;-,~re. n~l. req~jred 10 ",!f.el ." Ih!! .::{iJaft.aiiii defl.i!h!iM"((jd.@jfl <:b~( ·;'(1I!i~1 ·· be
a~fhori4.7 j(r: ":t~ ~~~~Rp'qf#~g-· ·~U:fi~i.~ te~~)o'· ;fn"et , the
p'rov;siorjs ojtbis,co'i;J[' . . .
...~.:
:
-.
206.3 Impact Loads The live loads specified in Secti ons 205.3 shall be assumed to include il llow3ncc for ordinary impacl conditions. Provisions shall be made in the structu ral design for use s nJld loads thaI in volve unu sual vibration and impact forces. Sec Section 206.9. 3 for impact loads for cranes, and Section 206.10 for heliport an d helistop landing areas.
206.3.1 Elevators All elevator loads shall be increased by 100% for impacl. 206.3.2 Machinery Fo r the purpose of design, the weight of machinery and movi ng loads shal! be inc rea~cd as follows to allow for impact: I.
Eleva tor Illachincry
2.
Light mac hinery, shaft - or motor-dri ven
3.
Reciprocatin g machinery or power-driven units 50%
4.
Hangers for floors and balconies
100% 20 %
33%
All percentages shall be increased where specified by the manufacturer. 206.4 Anchorag e of Concrt!tc and Ma so nry \Valls Concrete
by Secti on
J 04 .3.3. Such anchorage shall he c:lpablc o f resisting the load co mbinations of Section 203.1 or 203.4 using the greater of th e win d or c
206.6 Retaining Walls Rerain ing walls shall be designed to resist loads due to the lateral pressu re of retained material in accordance with accepted engi neering pract ice. Walls retainin g draincd so il, where the surface of the retained soi l is level, shall be designed for a load, tI, equivalent to that exerted by a nuid weighing not less than 4.7 kPa per meter of depth and having a depth equal to that of the retained soil. Any surcharge shall be in addition to the equivalent nuid pressure. Retaining wal ls shall be designed (0 res ist sliding by at leas t 1.5 limes the latera l fo rce and overturning by at least J.S limes the overturning lIloment, using allowable stress design load s.
206.7 Water AccullJulation All roofs shall he designed with suffi cie nt slope or Climber to cnsure adequate dra inage after the long- term dcOec ti on from dC'ld load or shall be designcd to rcsisl ponding load, P, combined in accordance with Section 203 .3 or 203.4 . Ponding load shall include water accu mulation from any source due to deflection .
206.8 Uplift on Floors and Foundations In the des ign of baseme nl floo rs and similar approximately horizontal c1emellls below grade, the upward pressure V.I water, where appl ic nb le. shall be take n
the founda ti ons, slabs, and other co mponents s h,dl be designed to tolerate the mo ve ment or th
National Structural Code of the Plli!ippines 6 Edition VoIU01 0 1
2- 16
CHAP TEI1 2 - Minimum Design Loads
resist the upward loads caused by the expansive so il s, or the expansive soil shall be removed or stabili zed around
206.10 Heliport and Helistop Landing Areas
206.9 Crane Loads
In addition 10 other design requireme nts of this chapte r, hcliport and helistop la nding or touchdown
206.9. 1 Gellera l
I.
Dead luad plus
The crane load simi I be the ra led cHpacity of lhe erllnc. Design .Ioads for the runway be.lllls, including conn ections .1I1e1 SUppOIl bracke ts , of moving bridge cr,lI1cs and monorail cranes shall include the max imum wheel loa ds of Ihe crane and the vertical impact. lateral. nnd longi tudinal forces induced by the moving cra ne.
2.
Dead load plus a si nglc CO llcc lllrHted impact load, L , covering 0.1 m2 of 0.75 li mes the fuily loaded weight of the heli copter if it is equipped wit h hydrau lic·type shock absorbers. or 1.5 times lhe fully loaded we ight of the helicopter if il is cq uipped wi th a ligid or s kidtype landing gear.
206.9.2 Maximum Wheel Load
The dead load plus a uniformlivc load. L, of 4.8 kPa. The rcq uircd liye load may be reduced in ac.cordance with Seclion 205.5 o r 205.6.
The maximum wheel loads shall be the wheel loads produced by Ihe weighl of Ihe bridge. as appl icable, plus Ihe sum of the rated capacity and (he weight of (he trolley with the trolley posi tioned all its ru nway whe re Ihe resulting load effect is ma ximum .
206.9.3 Vertical Impact Force The maxi mum wheel loads of the crane shall be increa~ed by th e pe rcentages shown below to determine th e induced vertica l impact or vib ration force:
I.
Monorai l c ran es (powered)
25 %
2.
Cab·oper:lIcd or remotely operated bridge c ra nes (powered)
25%
3.
Pcnd ant·oper:lled bridge cra nes (powered )
10%
4.
Bridge cranc,"i or monorail cranes with hand ·gcHrcd ridge. trolley and hoist
0%
206 .9.4 L'lIeral Fo rce The latera l force on crane runway bcams wi th electrica lly powered trolleys sha ll be calculated as 20% of the sum of the rated capaci ty of the crane and the weight of the hoist [lnd trolley. The lateral force sha ll be assu med to act horizontally at the tracti on surface of a runw ay beam, in ei ther direction perpendicular to the beam, and shall be distributed with due regard {Q the latera l stiffness of the runw,IY bea m ill1d support ing struct ure.
206.9.5 Longiludinal Forces The longilUdinal force on cra ne runw,lY bcallls, e.xcept for bridge crancs with hand-geared bridges, Sllllll be calculated iI.... 10% of the lll
As socia tion of Structural [:n9ineers of the PhilipPil1 cs
CHAPTER 2 ~" Minimum Design Loads
APPROVED. jurisdiction.
207.1 General 207.1.1 Scope Buildings, towers and other vertical structures, including the Main Wind-Force Resisting System (MWFRS) and all components and cladding thereof, shall be designed and const!1lc!cd to resist wind loads as specified herein. 207.1.2 Allowed Procedures The design wind loads for buildings, towers and other vertical stl1lcturcs , including the MWFRS and component and cladding elements thereof, sha!! be determined using one of the following procedures: (I) Method I Simplified Procedure as specified in Section 207.4 for building meeting the requirements specified therein; (2) Method 2 - Analytical Procedure as specified in Section 207.5 for buildings meeting the requirements specified therein; (3) Method 3 - Wind Tunnel Procedure as specified in Section 207.6.
207.1.3 Wind Pressures Acting on Opposite Faces of Each Building Surface In the calculation of design wind loads for the MWFRS and for components and cladding for buildings, the algebraic sum of the pressures acting on opposite faces of each building surface shall be taken into account. 207.1.4 Minimum Design Wind Loading The design wind load, determined by anyone of the procedures specified in Section 207 . 1.2, shall be not less than specified in (his section.
to
the
authority
having
BASIC WIND SPEED. V Three-second gust speed at JO rn above the ground in Exposure C (see Section 207.5.6.3) as determined in accordance with Section 207.5.4 and associated with an annLlal probability for 0.02 of being equaled or exceeded. (50-years mean reCllrrence interval). BUILDING, ENCLOSED is a building that does not comply with the requirements for open or partially enclosed buildings. BUILDING ENVELOPE. Cladding, roofing, exterior wall, glazing, door assemblies, window assemblies, skylight assemblies, and other components enclosing the building. BUILDINGS, FLEXIBLE. Sleoder buildings that have a fundamental natural frequency less than I Hz. BUILDING, LOW-RISE. Enclosed or partially enclosed building that comply with the following conditions: I.
Mean roof height h less than or equal to 18
2.
Mean roof height II does not exceed least horizontal dimension.
Jll.
BUILDING, OPEN. A building having each wall at least 80 percent open. This condition is expressed for each wal! by the equation Ao c 0.8 Ag where BUILDING, PARTIALLY ENCLOSED is a building that complies with both of the following conditions:
1.
the total area of openings in a wall that receives positive external pressure exceeds the slim of the areas of openings in the balance of the building envelope (walls and roof) by more than 10%; and
2.
the total area of openings in a wall that receives positive external pressure exceeds 0.5 m2 or I percent of the area of that wall, whichever is smaller, and the percentage of openings in the balance of the building envelope does not exceed 20 percent.
207.1.4.1 Main WindRFol'ce Resisting System
The wind load to be llsed in the design of the MWFRS for an enclosed or partially enclosed building or other structure shall not be Jess than 0.5 kPa multiplied by the area of the building or structure projected onto a vertical plane norillal to the assllmed wind direction. The design wind force for open buildings and other structures shall be not less than 0.5 kPa multiplied by the area AI as defined in Section 207.3.
Acceptable
2·17
207.1.4.2 Components and Cladding The design wind pressure for components and cladding of buildings shall not be less than a net pressure of 0 ..5 kPa acting in either direction normal to Ihe surface . 207.2 Definitions The following definitions apply to the provisions of Section 207 .
th
National Structural Code of the Philippines 6 Edition Volume 1
2-18
CHAPTER 2 --- Minimum Design Loads
These conditions equations: I. 2_
A ..
are expressed
by
the
following
> 1.10 A",
Ao > smaller of (0.5m 2 or 0.01 Ax) and A",IAs; S 0.20
nUILDlNG OR OTIIER STRUCTU RE, REGULA RSHAPED. A building or other structure having no unusual geometrical irrcguhuity in spatial forlll. nUII-DING RIGID. A building or other st ru cture whose fundamental frequency is greater than or equal to I H z. n UILDING, SIMPLE DIAPHRAGM. A building in which both wi ndward and leeward wind loads arc transmiHcd through Door and roof diaphragms to the: same verri cnl MWFRS (c.g .• no stnlctural separations). COM PONENTS AND CLADDING. Elements or the building envelope that do not qualify as part of the MWFRS . DESIGN FOnCE, F, is the equivalent stati c rorce to be llsed in the determination of wind loads for ope n buildings and other structures. OgSIGN PRESSURE,p, is the equivalent stati c pressure to be used in the determination of wind loads for buildings.
EA VE HEIGHT, h . The di stance from Ihe grou nd surfacc adjacent to the building to Ihe roof cave line at a particular wall . If fh e height of the eave v
GLAZING. Glass or transparent or translucent plastic sheet used in windows, doors, skyl ights, or cu rtain wal ls. GLAZING, IMPACT n ES ISTANT. Glazing that has been shown by testi ng in accordance with ASTM EI886 and ASTM £1 996 or other approved test methods 10 withstand the impact of wind -borne missiles likely to be generated in wind-borne debris regions during design winds. HILL. With respect 10 topogr;'lphic effects in Section 207.5_7 , a land su rface charac terized by strong relief in any horizontal di rection (Figure 207~4) IMPACT RESISTANT COV EnING. A covering designed to protect glazi ng, which has been shown by testing in accord ance with ASTM EI 886 and ASTM E 1996 or other approved test methods to withstand the impact or wind-bOl:ne debris missiles likely to begenerated in wind~b(}rnc debris reg ions during design winds. IMI'OnTANCE FACTOR, I ... A ractor that accounts for the degree of hazard to huma n life and damage to property. WIND -FORCE RESISTING SYSTEM MAIN (MWFRS). An asse mblage of souctural elements assigned to provide support and stabil ity for the overall st ructure. The system generally receives wind load ing from more than one surface. MEAN ROOF HEIGHT, h . The average of the roof eave height and the heigh t to the hi ghest point on the roof surface. except that. for roof angles of less than or equal to 10°, the mean roof height sh
OTHEn STRUCUTU n ES are nonbuilding stru ctures including poles, masts. trussed towers. and bill boards {hilt are not Iypically occupied by persons but arc also covered by this Code. RECOGNIZED LITEHATURE. Pub lished research findings and tcc hnicnl papers Ihm arc approved.
IUDGE. With respecl to topographic crfects in Sc(;t ioll 207.5.7 an elongated crest of a hill ch;\f<\ctcril.cd by stro ng relief in two directions (sce Figure 207-4).
sII r fa ('(~.
Associ ,ltlon of Stru ctu ra l Engineers of the Philippines
CHAPTEf1 2 - Minimum Design Loads
WIND-DORNE DEBRIS REGIONS. typhoon prone regions located:
Area, wi thin
Within 1.6 km of the coastal mean high water Iinc
I.
where the basic wind speed is equal 180 kph. 2.
(Q
or greater tlwn
In areas where the basic wind speed is equal to or greater than 190 kph.
207.3 Symbols and Notalions The following symbols and notation apply only to the provisions of Section 207:
A = effective wind area, 1112 Aa ::: ampJilUde factor for estimation of
III
[or other
structures. AI ::: area of opcn buildings and other struclUres cit h l~r norillal to lhe wind direction or projected on a plane normal to the wind direction , m 2 Ac ::: the gross area of that wall in which A(I is identified,
m' Agi
:::
the sum of the gross surface areas of the buildi ng envelope (wall s and roof) not including A $' rn 2
All A"i
A"S' As
a B lJo ill!
BOI•
:;: : total area of openings in a wall that receives positive ex ternal pressure, m 2 :;;: [he sum of the areas of openings in th e bui ldin g enve lope (walls and roof) not including A", 1112 == total area of ope nings in the building envelope. m2 ;:: gross area of the solid freestandin g wall or solid sign, 111 2 = width of preS$ure coefficient zone, 111 == horizontal dimens ion of a bu ilding, lower or other s tnlcture measured normal to wind di rection, III == horizon tal dimensio n at the base of a structu re, III = horizontal dimension
b :;: : mean hourly wind speed factor in
Eq. 207- I 4 frolll
Table 207-5
b ;
3-second gust speed factor from Table 207-5 ;: force coefficient to be used in the dClcnnination o f wind loads for olher structures eN == net pre..'isure coefficient to be used in determination of wind loads for ope n buildings ;; external pressure coefficient to be used ill the l• detennination of wi nd loads for buildings C :; lUrbulcil cc in tensity faclor in Eq. 207-5 from T'lbl e: 207-5 f) :; diametcr of a circula r s lmcturc or member, III D' ; depth of protmding elements such as ribs and spoilers, III Do = su rfacc drag coefficient P ; design wind force for other st ructures, kN G :; gust effcct factor for rigid buildings; al!lo coli lcd "simplified dynamic response factor" and is C/
e
2-19
eq ui va len t to Gf with R (resonan t response factor) assumed as zero Gf ; gust effect factor for MWFRS of flexible buildings and othcr structures, including poles, masts, billboards, and trussed lowers; also called "dynamic response faclor" G(.~m ;;combined net pressure coefficient for a parapet GCp = product of external pressure coefficient and gust effect factor to be used in the dcterillinatio n of wind loads for buildings GCp/ ;; product·, of equivalent extemal pressure coefficient and gust effect factor to be used in the dctenninalion of wind loads for MWFRS of low· rise bu ildings GC~,; = product of imernal pressure coefficient and gus t effect factor fa be used in the determination of wind loads for buildings gQ ;; peak factor for backgrou nd response in Eqs. 207·4 and 207-8 CN ;; peak factor for resonant response in Eq. 207·8 g, ;; peak factor for wind response in Eqs. 207.4 and 207-8 N ;; height ofhilJ or cscarpment in Figure 207A, III II = mean roof height of a building or height of other structure, except that cave height sha ll be used for roof angle Oof les s than or equa l to 10", III fir = roof eave height at a part icular wall , or the average height if the eave varies along the wall '\1" = impo rtance factor I; ;; intensity of turbulen ce from Eq , 207-5 kill ::: we ight distribution factor for est im ati on of tl\ for other structures K f ' Kz. KJ ;; multipliers in Figure 207-4 to obtain K :f K,f = wind directionali ty faClaf in Table 207·2 K" ::: veloc it y pressure exposure coefficient eva lu ated at heigh t z;; II K= ;; veloci ty prcssure exposure coelTicient evaluated at height z K., :; : topographic factor as defined in Section 207.5.7 L :; horizontal dimension of a building measured parallel to the wind direction. m ,.-" ::: distance upwind of crest of hill or escarpment in rig 207A to where the difference in ground elevation is half the height of hill or escarpment, III L: = integral length scale of turbulence, 111 . L,
;; horizontal dimension of return corner for a sol id frees tandin g wa ll or solid s ign from Figure 207·20. III
t f1I,
illlegra l length scale factor from Table 207·5, III ratio. o r the rati o of att ached masses (c.g.
= mass
National Structural Code of the Philippines 6
111
Edition Volu me 1
2·20
CH AP TER 2 .. Minimum Design Loads
of the tower. an equivalent mass ratio shall be taken Mn :::; mass factor for esti mation of III for other stru ctures N, = reduced frequency from Eq . 207·12 11/ ::;: building natural frequency, Hz " = design pressure to be used in the determination of wind loads for buildings. kPa PI- ::: wind pressure acting on leeward [ace in Figure 207-9, kP" flllt! ne t des ign wind pressure from Eq. 207-2, kPa P'~f')= ncl design wi nd pressure for Exposu re B at II::: 9 III and I .. = 1.0 f,om Figure 207·3 , kPa PI' ::: co mbined net pressure On a parapet from Eq. 207 -20, kPa /JJ :::; si mplifIed design wind pressure from Eq . 207- 1, kPa PJ I) ;;: si mplifi ed design wi nd pressure for E xposure B a.1 II = 9 m and I .. = 1.0 from Figure 207-3, kPa PII' :::; wind press ure acting on windward face in Figure 207·9, kPa Ph = plan-shape factor for cS lil11al iOIl of "I for other st ructu res Q = background response factor from Eq. 207·6 lJ ::: velocity press ure, kPa q" ::: velocity pressure evaluated at height z ::: ii, kPa qi ::: velocity pressure for internal pressure determinatio n, kPa qp ::: ve loci ty press ure at lOp of parapet, kPa q~ ::: velocity pressure evaluated at height z above ground , kPa R ::: resonant re spo nse fa cto r from Eq. 207-10 Rna::: aspect rati o factor for cstimalion of for other strucLUres, eva luated at the base widlh , Bo RII , R,.. II,. values from Eq . 207 - 13 Ri ::: reduction faclOr from Eq . 207- 16 Nil :: va lue from Eq. 207- 11 s ::: vertical dim ension of th e solid freestanding wall or . solid sign from Figure 207 -20, m. r ::: rise-to-span ratio for arched roofs. V = basic wind speed obtained from Table 207-1, kph. The basic wind speed corresponds to a 3-second gust speed al 10 rn above ground in exposu re category C Vi := ullpartitioned in le rnal vo lu me, m 3 \I: :::: mean hourl y wind speed al heightz, kph W ::: width ofa building in Figures 207- 12 and 207-14 A and B and width of span in rig urcs 207 ~ 13 and 207 -15 , III X := distance to center of pressure from winciwHfd edge in Figure 207-18 .111 x ::: tli stancc upwind or down w ind of crest ill Figure 207 · 4, III 1. :::: heig ht above ground level. In Z :::: cquiva lclll height of ~tnJc turc, III
=
"It
=
Zg
:;:; nominal height of the atmospheric boundary layer
used in thi s standard Values appear in Tab le 207-5
Zmitl :::: exposure constant from Table 207~5 3·second gust~speed power Jaw exponent from Table 207·5 = reciprocal of a from Table 207 ·5 Ii ::: mean ho url y wind-speed power law exponent III Eq . 207·1 4 from Table 207-5 fJ ::: damping ratio, perce nt critical for buildings o r othe r structures PI := slructural damping ralio, percent critical for other structures Ba := aerodyn amic dampin g rat io, percent crit ical for other structu res e rati o of solid area to gross area for open sign, fa ce or a tru ssed tower, or lattice structure A. ;:;: adjustme nt fac tor for building height and exposure from Figures 207-2A and 207-3 E = integral length scale power law exponent in Eq. 207.7 from Table 207·5 ,/ = value used in Eq. 207. 13 (see Section 207.5.8.2) p :;:; roughness factor B :;:; angle of plane of roof from horizontal, degrees v :;:; heighHo -widtb ratio for so lid sign (J.
:::
a
=
207.4 Method I - Simplified Proeedure 207.4.1 Scope A building whose design wind loads arc determined in accordance with this section shall meet all the cond ition s of Sections 207.4.1.1 or 207.4. 1.2. If a building qualifies on ly under Secli on 207.4. 1.2 for design of its components and cladding, then its MWFRS s hall be designed by Method 2 or Method 3. 207.4.1.1 Main Wind-Force Resisting Systems For the design of MWFRSs the bui lding must meet all of the following condi tions:
L
The bu il ding is a simple diaphragm building as defined in Section 207.2 .
2.
The building is a low-rise building as defined in Secti o n 207.2.
3.
The bu ilding is enclosed as defi ned in Section 207.2 and conforms to the wind -borne debri s provisions of Section 207.5 .9. 3.
4.
The building is a regular-shaped buildin g or SlruclUre
as defined in Section 207 .2. 5.
The building is not classified as a flexible building as defined in Sec tion 207.2
6,
The building docs not have response charac terist ics ma king il subject to across wind load ing , vortex
Association of Structural En9in eers o f the Philippines
CHAPTER 2 - Minimum Desig n Loads
2·2 1
shedding, instabi lit y due to ga lloping or nutter; and does not have a site location for which channeling effects Or buffeting in the wake of upwind obstructions warran t special consideratio n.
windward and leewa rd net pressures, fJJ shall be determined by the following equation:
7.
The buildi ng has and approximately symmetri cal cross-sec tion ill each direction with either a flat roof or a gable or hip roof wit h 0::: 45°.
8.
The building is exe mpted from torsional load cases as indicated in Note 5 of Figure 207-10, or the torsional load cases defined in Note 5 do not con trol the design of any of the MWFRSs of the building.
207.4.2.1 .1 Minimum Pressures The load effects of the design wind pressures from Section 207.4.2. 1 shall not be less th an the minimum load case from Section 207. 1.4 .J assllming the pressures, PSI for zones A, B, C, and D all equal to +0.50 kPa, while assumin g zones E, F, 0, and H all equal 100 kPa.
(207-1 )
207.4.2.2 Components and Cladding 207.4.1.2 Components and Cladding For the design of co mponcms and cladding the bui ldi ng must meet all [he conditions: 1.
The mea n roof height h must be less to 18 m.
than or equal
2.
The building is enclosed as defined in Secti on 207 .2 and conforms to the wind-borne debris provisions of Section 2075.9.3.
3.
The building is a regular-shaped building or structure as defined in Section 207.2.
4.
The building docs /l ot have response charac teristics making it subject to across wind loadin g, vortex shedd ing, ins ta bility due to galloping or flutter; and does nol have a sile location for which channeling effects or buffeting in the wake or upwind obstructions warra nt special co nsideration .
5.
The bu ilding has either a nat roof, a gable roof with 0 < 45°, or a hip roof wI O:s 27°.
Net design wind pressures, Pnc" for the components and cladding of buildings designed using Method I represent the net pressures (sum of internal and external) to be applied nonnal to each building surface as shown in Fig. 207-3. Pntl shall be detennined by the following equation:
(207-2) 207.4.2.2.1 Minimum Pressures The posi tive design wind pressures, PfIt"/, from Section
207.4 .2.2 shall not be less th an +0.50 kPa, and the negative design wind pressures . PnCfl from Section 207 .4.2.2 shall not be less th an -0.50 kPa. 207.4.3 Air Penneable Cladding Design wind loads de termined from Figure 207 .3 shall be used for all air permeable claddin g unless approved les t data or the recognized literature demonstrate lower loads for the type of air permeable cladding being considered . 207.5 Method 2 - Analytical Procedure
207.4.2 I.
D(~sign
Procedure
The basic wind speed V shall be determined in accordance wilh Section 207.5.4. The wind sha ll be
assumed to come fro m any horizont al directi on. 2.
An importance factor I". shall be det ermined ill accordance with Section 207.5.5.
3.
An ex posure category shall be determined in acc ordancc wi th Secti on 207.5 .6.
4.
A heighl and exposure adjustll1cnt coeffi cient ,A, shall be determined from ri gu res 207~2 and 207~3.
207.4.2.I I\:Jain Wind-F'orcc Resisting System SimpliJicd de sign wind pressures, p... for the MWFRSs of low -rise simple diaphragm buildings represellt the net pressures (sum of internal and ex ternal) to be applied 10 the Ilorizoillal and ve rti cal projectio ns of btli lding surfaces as sho wn in Fi gures 207- r an d 207-2. For the horizontal pressures (;I.o nes A, B, C. D), PJ is the combinat ion of the
207.5.1 Scope A building or other struct ure whose design wind loads are de termined in accordance with th is section shall meet all of the following conditions: J.
The building or other structure is a regular·shaped bu ilding or slmcture as defined in Secti on 207.2.
2.
The building or other st rll cture does not have respo nse win d loading, vortex shedding, instability due to g~l lI opin g or flutler; or does nol have a site locmioJl for which chanlle ling effect or buffeting in the wake of upwind obstruc tions warrant special consideration.
207.5.2 Limitations The pro vis ion of Sect ion 207 .5 take i nlo consideration the load ma gnifi cation effecl caused by gusts in resonance with al ong-wind vibrat io ns of llexib le building or other structures. Buildings or other st ructures not mee ting the
1h
National Structural Code of U"l e Phi lippine s 6 Edition Volume 1
2·22
CHAPTER 2 - Minimu m Design Loads
requirements of Section 207.5.1. or having unl/suaJ shapes or response characteristi cs shall be designed usi ng recogni zed literature documenting such wind load effects or shall usc the wi nd tUHnel procedure speci fied in Section 207.6. 207.5.2.1 Shielding There s hall be no reductions in velocity pressure du e to apparent shieldin g aflord cd by buildin gs and other structures o r terrai n features.
207.5.2.2 Air Permeable Cladding Design wind loads delcmlincd from Section 207.5 shall be used for air permeable cladding unless approved lest data or recogni zed literature demonstrate lower loads for
I
I
I
207.5 .4.1 an d 207.5.4 .2. The wind sh,,;\ D;: come from any horizon tal direction.
:::'l ~ : \1! p i'd ;\\
207.5.4.1 Special Wind Regions The basic wind speed shall be increased whcu.:: rc.:;ords O f experience indicate that Ihe wi nd speeds arc higher th an those refl ected in T able 207-1. Mountainous lCITa in, gorges, and special regi ons sh~ill be examined for unusual wind conditions. The authority havin g jurisoicl ion shall , if necessary, adjust the values given in Table :W: i to . account for higher local wind speeds. Such ndj u'c\ il)C iJ! shall be based on meteorological infonnation and an estimate of the basic wind speed obtained in accordance with the provisions of Secti on 207.5.4 .2.
I.
The basic wind speed V and wind directionality factor Kd shall be detennined in accordance with Secti on 207.5.4 and Table 207·2 respecti vely.
2.
An importance factor I,v shall be determined in accordance with Section 207.5.5.
207.5.4.2 Estimation of Basic Wind Speeds from Regional Climatic Data Regional climatic data shall only be used in lieu of the basic wind speeds given in T able 207 · 1 when: ( I ) approved extreme-value statis tic al -analysis procedures have been employed in reducing the data; and (2) the length of record, sa mpling error, averaging time, anemometer height, data quality. and terrain exposure have been taken into account.
3.
A n exposure category or exposure ca tegories and ve locity pressure ex posure coefficient Kt or Kit , as applicable, shall be dctennined for each wind direction in accordance with Section 207 .5.6.
207.5.4.3 Limitation Extreme typhoons have not been considered developing the basic wind·speed distributions.
the lype of air perm eable cladding being considered.
207.5.3 Design Procedure
4.
A topographic faclOr K!,t shall be determi ned in accordance wit h Secti on 207.5.7.
5.
A gus t effect Factor G or GI , as applicable, shall be determined in accordance with Section 207.5.8.
6.
An enclosure classification' shall be determi ned in accordance with Section 207 .5.9.
7.
Ime rn al pressure coe ffi ciclH GC,li shall be determined in accordan ce with Section 207.5. J I. J •
8.
External pressure coeffi cients Cp or GC.~'I' or force coefficients CI' as applicable, shall be determined in accordance with Secti on 207.5.11.2 or 207.5.1 U. respec t ively.
9.
Velocity pressure q, or q", as applicable, shall be determined in acco rd ance with Section 207.5 . 10.
207.5.4.4 Wind Directionality Faclor The wind direc ti onality factor, Kill shall be determined frol11 Table 207· 2. This fac tor shall on ly be applied when used in conjunc tion wit h load combinations speci fied in Sections 203.3 and 20104 .
I O. Des ign wind load p or F sljaiJ he detc rm ined ill accordance with Section, 207.5.12. 207.5. 14, and 207.5 .15. as appl icable.
in
207.5.13.
207.5.4 Basic Wind Speed Thc bas ic wind speed, V, used in the delenninmion of des ign wind loads on buildings and other structures shall be as given in Tab le 207-1 except as provided in Sections
Association of Structural Engineers of the Philippines
CHAPTER 2 - Minimum Design Loads
Table 207 -I Wind Zone for the Different Provinces of the Philippines Zone Classification Wind S ced)
Table 207-2 Wind Directionality Factor, Kd
Provinces
~asic
Albay, Aurora, Batanes, Cagayan, Camarines Norte, Camarines Sur, Catanduanes, Eastern Samar, Isabela, Northern Samar, Quezon, QUlIlllO, Samar, Sorsogon Abra, Agusan uel NOlte,
Zone I (V= 250 kph)
2-23
Structural Type
Directionality Factor Kd*
Buildings Main Wind Force Resisting System Components and Cladding
0.85 0.85 -
Arched Roofs
0.85
Chimneys, Tanks, and Similar StlUcturcS Square Hexagonal Round
0.90 0.95 0.95
Agusan de! SU[, Aklan,
Antique, Apayao, Balaan, Batangas, Benguct, Biliran, Bohol, Buiaean, Camiguin, Cariz, Cavitc , Cebu , Compostcla Valley, Davao Oriental, Guimaras, Ifugaa, Ilocos Norte, lIocos Sur, Iloilo,
Zone 2 (V = 200 kph)
Zone 3 150 kph)
(V=
_..___ ._~ ___ ~__
Kalinga, La Union, Laguna, Leytc, Marinduquc, Masbatc , Misamis Oriental, Mountain Province, National Capital Region, :"Iegros Occidental, Ncgros Oriental, Nueva Ecija, Nueva Vizcaya, Occidental Mindoro, Oriental Mindoro, Pampanga. Pangasinan, Rizal, Romblon, Siquijor, Southern Leyte, Surigao del NOiiC, Surigao del Sur, Tarlac, Zambalcs BasiJan, Bukidnon, Davao del Norte, Davao del Sur, Lanao del Norte, Lanao del SUf, Maguindanl1o, Misamis Occidental, North Cotabato , Palawan , Sarangani, South C. otabato ,Sl.dtan Kudarat, Sulu, Tawi~tawi, Zamboanga del NOlie, Zamboanga de! Sur,
_.-
Solid Signs
0.85 "---
Open Signs and Lattice Framework
0.85
Trussed Towers Triangular, square, rectangular All other cross sections
0.85 0.95
Dir('Cfionalif}, Factor Kd has been calibrated with combinations of loads speciji~d ill Seclioll 203. This fin'lOr shall only he applied when IIsed in C()lIjuIIClioll wilh load combillatiol/S specified in Section 203.3 alld 203.4.
l
Z'lll1~""ll~_~_b-"ga y_ _ __
National Structural Code of the Philippines 6
th
Edition Volume 1
2-24
CHAPTEH 2··· Minimum Design Loads
207.5.5 Importance Factor An imp0l1ance factor, 1\\., for the building or other structure shall be determined from Table 20 7~3 based on building
For each wind direction considered, the upwind exposure category shaH be based on ground surface roughness that is determined from natural topography, vegetation. and cons tru cted facilities. Table 207-3 Importance Factor, IIV (Wind Loads) ~,.----:-~----'--r-" "·"·-·" Occupancy Description I. Categ0.'2'
I
II III
IV
1.15
Esscil ti al -.- -~
-
-_._._- ._-
1.15
Ilazardous
Spccial q~c~e.~~~r Standard .9(;1?~p~I~C.)'.
1. 15 ---. _.. __ ... _1.00
V_- ' -_ Miscellaneotls '--_ _ _ _ _..1...-_ _0.87 _ ___ _ I
207.5.6.3 Exposure Categories Exposure B. Exposure 13 shall apply w here the grou nd
207.5.6 Exposure
- .. - ...- ........ - -_..
Surface Roughness D, Flat, unobstructed areas and water su rfaces. This category includes smooth mud flats and salt flats.
see Tah!!! !03· } /0/' t)'{)(!S (If (lCCII/ffl/tCY
IIl/der
('(Ich
c{ltegory.
207.5.6.1 Wind Directions and Sectors For each selected wind direction i.H which the win<1 loads are to be evaJualed, the exposure of the building or Sll11cture shall be determined for the two upwind sectors ex tend ing 45 ° either side of the selected wind directi on. The exposures in these two sectors shall h~ de termined in accordance with Sections 207.5.6.2 tlnd 207.5.6.3 and the exposure resulting in the highest wind loads shal! be used to represent the winds from thaI direction. 207.5.6.2 Surface Roughncss Categories A ground surface roughness within CilCh 4Y' sector shall be detennined for a distance upwind of the si te as defined in Seclion 207.5.6.3 from the categories defined in the fo llowing text . for the purpose o r assigning an exposure cClIcgory as defined in Section 207.5.6.3.
surf.'lCc roughness condi tion, as defined by Surface Roughness D. prevails in the upwind directi on fo r a dist:mce of at least 800 III or 20 times the height of th e building, whichever is gremer.
Exception : For buildings whose mean roof height is less than or equal to 1Q m, the upwind distance may be reduced to
450".. Exposu rc C. Exposure C shall apply for all cases whe re Exposure B or D does not apply. Exposure D. Exposure D shall apply where lhe ground surface roughness , as defined by Surface Roughness D, prevails in lhe upwind direction fo r a distancc greater than 1.5 km or 20 times the building height, which is greater. Exposure D shaH extend into downwind are,IS of Surface Roughness B or C for a distance of 180 m or 20 times the height of the building. whichever is greater. For a site loca ted in the transition zone between exposure categories. the category resulting in the largest wind
forces shall be used.
Exception: All imermediate exposure be/ween the precedi"g categqries is permilled in a transition zone provided that it is determined by a rational analysis method defined in rlie recognized literature.
207.5.6.4 Exposure Category for Main Wind-Force Resisting System 207.5.6.4.1 Buildings and Other Struc!ures For each wind direction considered wind loads ror the design o f the MWfRS determined from f-igUfc 7.07 '() :-; hall be based o n the exposure categories defined in
Section 207.5.().] . Su rf:)cc Roughness B. Urban and suburban areas, wooded areas, or other tcrrain " .witl1 numerou s close!y spaced obstnlctions having the size of sing J(> family dwell ings or larger. Surface noughn css C. Open tcrrain wit h SCilHerc.d obstructi ons havin g heights generally le:.;s than 9111. This category includes nat open coullIry. grasslands. :'lIld all watcr surfaces in regions with records of ex treme
207.5.6.4.2 Low-Rise Buildings . Wind loads for the design of the MWFRSs for low-risc huildings shall he dcterm ineD using a velocity press ure qh hased ;;) the exposure resulti ng in the highest wind loads for any wind directioll at the sile where. extemal pressu re coc fficieJlts GCp'( given in Fig. 207-10 arc used.
typhoo ns.
Association of Structural Engineers of the Philippines
CHAPTER 2 - Minimum Design Loads
201.5.6.5 Exposure Ca tegor y for Components a nd Cladding Components and cladding design pressures for all buildings and other structures shall be based on the exposure rcsuhing in the highest wind loads for any
direction at the site.
2·25
Notes: J. Case I: a. All compotlttllS and cladding. b. Main wind force ruisring s)'stem in Jow·rise buildings desig,,~d using FiGure 207·/0. Cast 2: a. All 1II0i" wind forct rrsislillg ;rySfCmS in bllildines e:ccepl ,hCJSt in low· rise buildings dtsig,,~d ftling
Figure 207· 10. h. Ail main wind force resislillg s),SI£'IIIS ill olirer
201.5.6.6 Velocit y Pressure Exposure C oefficient
2.
nI t!
sfrucrurtS. vl'locifY pressllre (!XPOl'II/'(1 wc/fi(:ie lll K, moy be ilefC mrilled
Based on the exposure category determin ed in Sec tion
f rom Ihefollowin c!orlllufa:
207.5.6.3, a ve loci ty press ure ex posu re coefficie nt K( 01' K h , as applicab le, shall be determined from Table 207·4.
For
For a site locCHed in a transition zone between exposure categories, thai is, ncar to a change in ground surface roughness, intermediate values of K: Or K", between (hose shown in Table 207·4, are pennitted, provided that they are determined by a ralional analysis method defined in the recogni zed literature. Table 207-4 Velocity Pressure Exposure Cocrticienls', Kh and Kz Hcigh l Exposure (Note I) above Ground leYel "
C"." I
C
..
asc
2
OUt'S 1& 2
Cases 1& 2
0.90
1.08
0.94
I. I 2
I--=' O("-':~"-')-:C5'- "·-·-C -l. 7-0- - -C-)~i7- -0.8S-----·j:()-3-·-
......_... ... - .... '
6
0.70
7.5 - ".... _ ....... ,.
0.70
0.62 0.66 .. ...._-...
9
0.70
0.70
12
0.76
0.76
15
0.81 ....
0.81
1.09
18
0.85
0.85
1.1.1
1.27 1.)1
21
0.89
0.89
I 17
1.)4
.--_ .." .
...0.98 ..... ... .. ... 1.16 . . - .... 1.04 1.22
24
0.93
0.93
1.21
1.38
U.96
0.96
1.24
1·10
30
0 .1)1)
0.99 .....
1.26
1.43
36
1.04
1.31
1.48
42
1.09
1.04 1.(19
1.36
1.52
48
1.13
...1. 13 '.
1.39 . .....
1.5.\
54
1. 17
1.17
1.43
I .S8
60
1.20
1.20
[ .46
I ,(J !
75
1.28
1.2R
1..\3
1.68
90
1.3.\
U.\
1.59
1.73
1.6:1 1.69
I.n
.. ..... ... -
. .
105
1.4 I
1.41
120
1.47
1.47
135
ISO
'~
1.56
.
1.52 1.56
----
For 4.5 III S as al
1.82
1.73
1.86
1.17
1.89
)".
{7--1
K:",2.0
'
201.5.7 T opog raphi c E ffects 207.5.7.1 Wind Speed-Up Over Hills, Ridges, and Escarpmen ts Wind speed·up effec ts at isolated hi lls, ri dges , an d escarpments constitutin g ab ru pt cha nges ill th e genenJ
lOpography, located in any ex pos ure category, shall be incl uded in the design when buildi ngs and oth er site conditi ons and locations of structures mee t all of the follow ing conditions: I.
The hill. ridgc , or escm'pment is i sol~Hed and ullobstructed upwind by other similar topographic features of compar;'lblc height for 100 limes the height of thc topographic fCaiure (1001-1) or 3.2 kill whichever is less. TIlis d istance shall be measured horizontally from the point at which the height H of lhe hill . ridge. or escarpmcm is determined.
2.
The hill, ridge. or escarpment protl1ldes above the height of upwind len'ain featu res within a 3.2 kill rad ius in any quadran l by a faclOJ' of two or more .
J.
The structure is localed as shown in Figure 207·4 in thc upper one- hall' of rt hill or ri dge or nca r th e crest or an esc arpmcnt.
.-
27
z < 4.5 III
llmll l)f' eq u:d 10 4.5m for Exposur~s C :lIld D and 18m (or Exposure B.
5. II is greater
N,JIlonal Structura l Code of U1H PI1ilipPIncs Gill Edition Vo lum0 1
2·26
CHArJTER 2 ·- Minimul1l Design Loads
207.5.8.2 Flexible or Dynamically Sensitive Structures 207.5.7.2 Topographic Factor The wind speed·up effect shall be included in the calculation of design wind loads by using (he faclOr Kl , :
For flexible or dynamically sensi ti ve suuctures as defined in Section 207 .2 the gust·effect factor shall be caiculated by
(207·3)
where K I , K1 and KJ are given in Figure
(207 ·8)
207~4.
If site condi ti ons and locations of structures do not meet all the conditions specified in Seclion 207.5.7.1 the KlI ::: 1.0.
gQ and g" shall be taken as 3.4 and 8R is given by
8R =J2 In(3,600Il J )+ 207.5.8 Gust Effect Factor The gUSl effect facto r shall be calculated as penniUed in Sections 207.5.8. 1 to 207.5.8.5, using appropriate values for natura] frequency and damping ra lio as permitted in Section 207.5.8.6.
0.577
~21n(3.6001l J )
(207·9)
R:;::;: the resonant response factor is given by
R~
I
pRn Rh R IJ (0.53+0.47R{.l
(207-10)
207.5.8.1 Rigid Buildings
R -(
For rigid buildings as defined in Section 207.2, the gust· effect factor shall be taken as 0.85 or calculated by th e fonnu la:
n -
N, =
7.47N,
(I
)
(207· 11 )
"0"'-
(207-12)
Vi
(207·4)
R, where
=:' __I_( I _,,-2")for l/>0 '/
R,
(207·5)
(207·13a)
27/'
=1 f Off) =0
(207· l3b)
where lhe subscript t in Eq. 207 ~ 13 shall be taken as h, B, and L. respective ly, where ii, 13.) artd L are defined in Section 207.3. .. ,
where
Iz
+ IO.3N,)"'/l
::: the intensity of turbul ence at he ight Z where Z ::; the equivalent height of the SlrUl:lUrc. defined as 0.6h, but not less tlmn lmi" for all building heights. Zmin and c are listed for each exposure in Table 207·5; gQand g,. shall be taken as 3.4. The background response Q is given by:
Q= 1+0.6
i B~" )0.63
(207·6)
1
Il,
::: building natu rHI frequency -
III
:;: ;: Rh selling '/ = 4.611 Ih/V;,
RI
:;: ;: Rn sellin g
1J ::;
RI
= RL setting 'I = 1 5.4I1IL/~
fI ~
= damping ralio, percent of critical ~
mean hourly wind speed (m/s)
at
height
l
determined from Eq . 207·14
-
( )"
- z_
V- =b , 10
where B. h '-Ire defined in Section 207.3: and Li :::: the intcgml length sC;:lle or turbulence at the eq ui valent height given by
4.611 I En /V:
V
where band !i arc constant s listed ill Table is the basic wind speed in kph.
(207.7)
In which f aile! E are consta nts lis ted in T;lble 207~5 .
Association of Structural Engineers of the Philippin es
(207·14)
207~5
and V
CHAPTER 2 - Minimum Design Loads
Tablc 207-5 Terrain Exposurc Constants
a z, (m)
-
Ii
-
.--.
207.5.9.3 Wind-Borne Debris
-B C D ---7.0 9.5 11.5 365 275 215 117 119.5 ----- 1111.5 0.84 1.00 1.07 --_.._. ... _.1/4 1/6.5 1/9 .... 0.45 0.65 0.80 --_._...• 0.30 _._._0.20 0.15 .. 0.010 0.005 0.003 ..---150--100 200 1/3 1/5 118 9 4.5 2.10
I~xposurc
~~---.-
;;
a ---=---
-.~---.--
b
c _.
----~-
Do --_._._.. . f (m) --
If
~~---
2-27
Glazing in buildings located in wind-borne debris regions shall be protected with an impact-resistant covering or be impact-resistant glazing according to the requirements specified in ASTM EI886 and ASTM EI996 or other approved test methods and performance criteria. The levels of impact resistance shall be a function of Missile Levels and Wind Zones specified in ASTM EI886 and ASTM E1996.
---~~
~--~-.~.
*Zrnin Z",",
(m) :::
minimum height used to ensure that {he equiv3knt height
greater or
l",,,,
or
Xh
Zis
for tmssed lowers, the height of (he
trnnsmission cable above ground, or 0.611 ror buildings and other structures. For 11:5 z. . ,". i shall be taken as z,o,o'
207.5.9.4 Multiple Classifications 207.5.8.3 Rational Analysis In lieu of the procedure defined in Sections 207.5.8.1 and 207.5.8.2. detcrmination of the gust~effcct factor by any rational analysis defined in the recognized literature is pennittcd.
If a building by definition complies with both the "open" and "partially enclosed" definitions, it shall be classified as an "open" building. A building that docs not comply with either the "open" or "partially enclosed" definitions shall be classified as an "enclosed" building.
207.5.8.4 Limillitions
207 .5.10 Velocity Pressure
Where combined gust-effect factors and pressure coefficients (GCp ' GCp ;' and GC"f) are given in figures and tables, the gust-effect factor shall not be determined separately.
Velocity pressure, CJl> evaluated at height z shall be calculated by the following equation: (207 -15)
207.5.8.6 Dynamic Properties
where K" is the wind directionality factor defined in Section 207.5.4.4, K~ is the velocity pressure exposure coefficient defined in Section 207.5.6.6, KZI is the topographic factor defined in Section 207.5.7.2. and q" is Ihe velocity pressure calculated using f:q. 207··15 at mean roof height h.
Values of natural frequency and damping ratio when lIsed as input parameters in calculations of the gust effect factor shall be obtained from full-scale measurements of the actual structure, from computer simulation. or from the estimation formulas given in Section 207.8.
The numerical coefficient 47.3 x 10-6 shall be used except where sufficient climatic data arc available to justify the selection of a different value of this factor for a design application.
207.5.9 Enclosure Classifications
207.5.1 I Pressure and Force Coefficients
207.5.8.5 Other Structures Procedures for calculation of the gust effect factor for other structures sha!l be taken from Section 207.7.
207.~.9.1
207.5.11.1 Intel-nal Pressure Coefficient
General
For the purpose of determining internal pressure coefficients, all buildings shall be classified as enclosed, partially enclosed, or open as defined in Section 207 .2.
Internal pressure coefficients, Gc.~)l·' shall be determined from Fig. 207~5 based on building enclosure classifications detennined from Section 207.5.9.
207.5.9.2 Openings
207.5.11.1.1 Reduction FHclor for Large Volume Buildings, Ri
A determination shall be made of the amount of openings in the building envelope to determine the enclosure classification as defined in Section 207.5.9. I.
For a partially enclosed building containing a single, unpartitioned large volume, the internal pressure
N;;ltiotlal Structural Code of the Philippines
Gill
Edition Volullw 1
2·28
CHAPTEr:l 2··· Minimum Design l.oads
coefficient, GC~II> shall be multiplied by the following reduction factor, Ri :
207.5.11.5 Parapets 207.5.11.5.1 Main Wind·Force Resisting System The pressure coefficicnts for the effect of parapets on the MWFRS loads arc given in Section 207.5.12.2.4.
(207-16)
where Aog
Vi
= total
area of openings in the building envelope walls and roof, in m2 = unpal1itioned internal volume, m3
207.5.11.2 External Pressure Coefficients 207.5.11.2.1 Main Wind-Force Resisting Systems External pressure coefficients for MWFRSs e,l arc given in Figures 207-6, 207-7, and 207-8. Combined gust effect factor and external pressure coefficients, GCl'f' are given in Figure 207-10 for low-rise buildings. The pressure coefficient values and gust effect factor in Figure 207 · 10 shall not be separated.
207.5.11.5.2 Components and Cladding The pressure coefficients for the design of parapet component and cladding clements arc taken from the wall and roof pressure coefficients as spccified in Scction 207.5.12.4.4. 207.5.12 Design Wind Loads on Enclosed and Partially Enclosed Buildings 207.5.12.1 General 207.5.12.1.1 Sign Convention Positive pressure acts toward the surface ilnd negative pressure acts away from the surface. 207.5.12.1.2 Critical Load Condition Values of extemal and interna! pressures shall he combined algebraically to determine the most criticill load.
207.5.11.2.2 Components and Cladding Combined gust-effect factor and external pressure coefficients for components and cladding GCI ) arc given in Figures 207- I I through 207-17. The pressure coefficient values and gust-effect factor shall not be separated.
207.5.12.1.3 Tributary Areas Greater than 65 m' Component and cladding clements with tributary areas greater than 65 1112 shal! be permitted to be designed using the provisions for MWFRS.
207.5.12.2 Main Wind-Force Resisting Systems 207.5.1 1.3 Force Coefficients Force coefficients Cj arc given in Figures 207-20 through 207-23.
207.S.12.2.1 Rigid Buildiugs of All Heights Design wind pressures for the MWFRS of buildings of all heights shall be determined by the following equation:
207.5.11.4 Roof Overhangs
(207-17)
207.5.11.4.1 Main Wind-Force Resisting System Roof overhangs shall be designed for a po~itive pre~sure on the bottom surface of windward roof overhangs corresponding to C~, :::: 0.8 in combination with thc pressures dctcrmined from Llsing Figures 207-6 and 207I ().
where q 'I
'I,
207.5.11.4.2 Components and Cladding For all buildings, roof overhangs shall be designed for pressures determineo from pressure coefficients given in Figures 207-1 Ill. C. D.
'I,
::::; q; for windward walls evaluated ilt height ! above the ground = q" for leeward 1\I(I/lS, side walls. and ron\< evaluated at height II = (fir for l\Iilldw(/rd walls, sid~ wails, leeward \\':111.and roofs of enclosed huildings ;lnd fOl" neg :il l\"\: internal prcssure evaluation in p,lrtially encloscd buildings ::;: q; for positive intcrnal pressure CVallJ;ili("~l partially enclosed buildings \vherc hei):I, · defined as the level of the highest opening Ii; ~:L,"' building that could affect the positive For buildings sited in wilj·.: i Ill' pressurc.
I\ssoCi,·ltICHl of Str"UCllJ('·ll E:nqinnus of the PhilipPines
CHAPTER 2 -- Minimum Design Loads
G
c" (G(~lI)
debris regions. glazing that is nOt impact resistant or protected with till impac t resislanl cove ring, shall be treated "s an opening in accordance wi th Secti on 207.5.9.3. ror positi ve int ernal pressure evalUilli on. qi may conserv
207.5.12.2.2 Low·Rise Building
, ! j,
Altern atively, design wind press ures for the MWFRS of Jow -rise bu ildings shall be dete rm ined by Ihe fo ll owing equat io n:
I
(207·18)
i
2·29
away from) the fro nl (exterior) side of th e parapet lJlI = ve loci ty press ure eval uated at the top of the parapet Gel''' = combincd net press ure cocfficient = + 1.5 for wind ward parapet = - I .0 for leeward pa rapet 207.5.12.3 Design Wind Load Cases
Th e. MWFRS of buildings of all heights, whose wind londs have be-cn dctcrmin ed under the provisions of Seclions 207.5. 12.2. I and 207.5.1 2.2.3, shall be des igned for the wind load cl-l ses as defined ill Fig. 207-9. The eccentri cit y e for rigid structu res shall be meas ured frolll the geometric cent er of the building face and shall be considered for eac h principal axis (ex. ey). The eccentri city e for nexible structures shall be determi ned from the fol lowing equation and shall be considered for each principal ax i s (ex. e ,.): e Q + 1.7/ , J(g"Qe Q )' + (CN Re R ) '
e= -
---
(207·2 1)
1+ 1.71, J(g"Q)' +(gR R)'
where
=- velocity pressu re evalu ated at mean roof
q"
(GCIJj ) (GCI ,,)
height 11 using exposure defined in Secli on 207 .5 .6.3 :::: external press ure coeffi cient frol1l Fi gure 207 10 = intemal pressure coeffi cient froll1 Figure 207-5
wh ere
=- eccentricity e as determined for rigid structures in Figure 207·9 = distan ce be tw een til e clastic shear cent er and centcr of Ill:lSS of each fl oor
/ " g Q.Q. gR. Ii shall be as defined in Secli on 207.5.8
207.5.12.2.3 fl exible Buildiugs
Des ign wind pressures for the MWFRS of flexible bu ildi ngs shall be delc nnined !'mlll the following cqu
The sign of the eccen tricity e shall be plus or minus. whichever causes the morc severe load effect.
Exeeplion:
whe re q. qi. Cpo and (CGpi ) arc as defi ned ill Secti on 207.5. 12.2.1 and (Ij = gust effect facto r is defined as ill Scclion 207.5.8.2.
Olle-sto"ry buildings with h less lhan or equa} .to 10 IrIJ bujldj!,g~ tWO ~'or!~~ 9' less framed . 1V;,h Iight'{rame co~'si . · !:ti~n..- j:m'q QlIt(4l"ngs. /)Vo sto.r!es or I~s~ 4.es~g~ed wit~'!/. '. . . p'lr.}JgM.f~lfeta"~nifF!trdesignet:tli>'-·load c(kt!'i" ba:siMtlff~Fjkur~;'2b7S9: ,c'" " " ,:' , " '.
207.5.12.2.4 Parapets
207.5.12.4 Compollents and Cladding
The dcsign wind press ure for the e ffect of parapets on MWFRSs of ri gid, lo w-rise. or Oexibl e buildings with nat , gable, Or hip roofs shal! be uctel'lllined by the following cq u
207.5.1 2.4.1 Low-Hisc Bui1dings and Buildings with h S 18 III
P,. =qpGC,.
(207·20)
Design wind press ures on com po nent II lld cladd ing c le ments of lo w-risc bui ldin gs wit h h ~ 18 In s.lall be detcnn ined from (hc fo ll owing eq uation :
where
1'='1'[ (GC,.l -(GC,,,) 1 = combined net pressu re 011 the p
the combina tion of tile Ilet press ures fro m fron t and bac k pa rapet surfaces. Plus (a nd minus) signs sign ify net prc!';s lI rc ;Klin g toward (and
(207·22)
where C/J. = velocily pressure cvaluated at mean roa r heigh t h using exposure defined in Section 2075 :6.3
111
National Structura l CoeJe of tile PJ'IilipPlnes 6 Edition Vot ume '1
2·30
C HAPTER 2 _. Minimum Design loads
(Gep ) = external pressure coefficients given in Figure 207- 11 through 207- 16 (CCIl ;)=. internal pressure coeffi cient given in Figure 207-5 207.5. 12.4.2 Buildings with" > 18 111 Des ign w ind press ures on components and claddin g fo r
where
Ge"
all buildings with h > 18m shall be determined from th e followin g equation : (20 7-23) where q q l!;
for wi ndward walls caicuialcd
;;:: q" for windward walls, side walls, leeward walls,
:::: veloc ity pressure evaluatcd at ill;.,' k',' . r the parapet :::: eX lern al press urc coeffi cients fro m Figu res 207 ·1 1 throu gh 207 -1 7 ~ int ernal pressure coeffici ent rrom Figu res 2()7~5, based on the poros ity of the parapet C!l\,(ljupc.
Two load cases shall be co nsidered. Load ~ ',,' /'.: ~ ~a ll consisl o f applying the app licable posit ive w;,11 prc:-.:-. u rc from Figure 207-I IA or Figure 207- 17 !t o illI: !-;"(lIl( surface o f the parapet while appl yi ng I!:-.: ;ll'i·;il'I!, le negati ve ed ge o r corner zone roof pressure flt .1l1 I-igu res 207- 11 throu gh 207-1 7 to the back surface. Load Case B $hall consist of applying the applicable posil ive wall press ure from Figure 207-IIA or Fi gure 2.(J' )· I'J 10 th e back o f the parapet surface, and appl yi ng Ihe :Ipplicab le negat ive wall pressure fro m Fi gure 207- i I A or Figure 207- 17 to the front surface. Edge and corner Wiles. sha ll be arranged as shown in Figu res 207- 11 thronl~h 207 -1 7 . GCp shall be detcnn ined for appropriate i''iO{ Ing le and effec tive win d arca from Fi gures 20 7~ 11 Ih)'();II',h 207 ~ J 7. If intcrnal press ure is present, both load t.::::·:;;.', ,' .hnuld bc. evaluated un der positive and negati ve internal press ure.
and roo fs o f enclosed buildings and for negati ve inte rnal pressure e va lua tion in partia ll y e nclosed buildings qi :::. q: for posi ti ve internal press ure eva luation ill part iall y cilcloscd bu ildi ngs where heig ht z is defined as the level o f the highes t opcning in the building thaI could affect the positive internal pressure. For buildings sited in wind-born e debri s regions, glazing th at is not impact res is(ant or protec(cd wit h an impact-resislant coveri ng , ~h all be treated as an opening in accordance with Section 207.5.9.3. For pos itive inte rn al pressure eval uati on, qi may conserva tive ly be evaluated at height " (q ; = q,,) ( Gel') :::: ex ternal press ure coefficient from Fi gure 207 · I 7 (GC,,;) = internal press ure coeffi ci.ent given in Fi gure 207-5
Pl us and min us sign s sig nify press ure ac tin g towa rd and away from the lOp s urface of the roof, fcspeCl ivtdy.
q and qi shall be eva lu ated using exposure derined in Sec ti on 207.5.6.3.
207.5.13.1.2 C ritical Lo ad Condition
<"
207.5.12.4.3 Alternalive Design Wind Press ures for Components and Cladding in Buildings with 18m
< 27m Alternati ve to th e req uirements o f Sectio n 207. S.12.4 .2, the design o f compo nent s and cladding fo r build ings wit h a mean roo f height greater tha n 18m and less tha n 27 m values from Figures 207-11 through 207- 17 sha ll be used on ly if the heighl to wid th ratio is o ne or less (except iI:\ pe rm itt ed hy Note (, of Figure 207-17) an d 10'1. 207-22 is used .
207.5.13 Des ign Wind Loads on Open Bui ld ings with Monos lo pe, Pitch ed , or Troughed Il oo fs 207.5.13.1 General 207.13. J.1 Sign Convention
Net pressure coeffi cien ts eN incl ude contrib utions from top and boltom surf5ccs. All load cases shown for cnch roo f angle shall be illv C'stiga led.
207.5.13.2 Molin Wind-Force Resisting Systems Th e net design pressure fo r the MWFRSs of l1)olloslopc, pi tched, or troughed roo fs shall be dCh.·nllillt ~ d I,'! t!i~~ following equat ion: (207-251 where
207.5.12.4.4 Parapets
ve-lod lY press ure cvalu,l1 cd at mean roo f height II lIsi ng lh e ex pos ure as defi netl in Section 207 .5.0.3 tlm t results in the. high~s! Wii ld l\lads ror any wi nd direction at the site = gust crfect factor from Seclion 207.5. X =:
The dc:\ ign wind pressure o n (hc compollc nts and c huJdin g clc lllellls of parapel:-; shall be designed by the
rol lowing equation: G
Associ;llion of Stru ctura l Engin o(HS of the P illiippines
CHAPTEH? .• Minimum Design I.oads
= net pressure coc nicicnt determined
= projected area
from Figures
207- 18A through 207-1 8D
normal
to
the wind
CX.CCpl
2-3 1
where
Cf is specified for the actual su rface area, mZ
For frcc roofs with an angle of phme of roof from horizontal 8 less than or equal to Y' and containing fascia panels. Ihe fascia panel shall be considered an inverted parapet. The contribution of loads on the fasc ia to Ihe MWFRS loads shall be determined lIsing Section 207.5.12.2.4 with If,. equal to q".
207.5.15.1 Rooftop Structures and Equipment for Buildings with II :S 18((/
The force 011 rooftop structures and equipment wi th Af less than 0.1 O/3h locat ed on buildings with Ii $ 18 III shall be determined from Eq. 207-28, increased by a factor of 1.9. The factor shall be permitted to be reduced linearly from J.9 to J.O as th e value of Aj is increased from 0.101317
207.5.13.3 Component and Cladding Elements
to Bh.
The net design wind pressure for component and ctadding elcments of lllonosJope. pitched, and troughcd roofs shall be dClcnnincd by the following equation :
207.5.15.2 Structures Supporting Antennas, C'lblcs, and Other Attachments and Appurtenances
(207 -26)
where
q,
= velocity pressure evaluated at mean roof hcight Ii using Ihe exposure as defined in Section 207.5.6.3 that resu hs in Ihe highest wind loads for any wind direction at the site = gust-cffect faclOr from Section 207.5.8 = net pressure coefficient detcI1l1ined from Figures 207-19A through 207-19C
207.5.14 Design Wind Loads on Solid Freestanding Walls and Solid Signs
The design wind force for sol id freestanding walls and solid signs shall be determined by the followi ng formula : (207 -27)
where
The wi nd loads on all stl1lclures supponing attachments and appu11cnances including antenna· and cablcsuppol1ing structures shall take into account the wind loads on all supported antennas, cables, 3l1achmcllls, and appul1enances. Guidance on wind loads on su pported antcllntlS shall be obtained from the TfA- 222-G (2005) sta ndard unless sufficient suppolling evidence can be obtained from recognized literature or frolll wind tunnel tests. Guidance on wind IOilds on supported cables shall be obtained from the ASCE Manual of Practice #74 (G uidelines on Electrical Trclnsmission Line Structural Loading) except that the gust effect factor for cables as give n in Section 207.7.3. or unless sufficient su pporting evidence can be obtai ned from recogn ized litermure or from wind tunnel tests. wind loads on suppo rt ed antennas, cables. illlachments, ilnd appuncll,mccs shall be applied at the lo(.:ali on of support 0 11 the support i ng structure.
Thc
qh
Gf
Cf A.I
= th e
velocity pressure evaluated at height II (defined in Figure 207-20) using exposure III Section 207.5.6.4.1 = gus t-effect factor from Section 207.5.8 = nel force coefficient from f-igure 207-20 ::: the gross area of the solid frees tandin g wall or solid sign , rn z
207.5.15 Design Wind Loads on Other Structures The design wind force for other strlJclllres shall be dctcnnined hy the following equation: (207-28)
whcre
G C,
velocity prcssure CVillU
207-n
207.6 Method 3 - ""ind Tunnel Procedurc 207.6.1 Scope
Wind tunnel tests sh<1 11 be used where required by Section 207.5.2. Wind tunnel testing shall be permitted in lieu of Methods I and 2 for any building or structure. 207.6.2 Test Conditions
Wind tUllnel les ts, or s im ilar em ploying fluid s olhcr than air. lIsed for the determinat ion of design w ind loads for any building or ot he r stnlcl urc. sl1
Thc nalunll atmos pheric bmllld
N;ltlonal ~.;trllctu{t!1 Co(Je of !lIe Plli1ipPl1l8S
()!L
Edition VoIUlIlc! 1
2<32
2.
3.
4.
CHAF)TE:li 2 ._. Minimum Design Loads
The relevant macro-integral length and micro-length scales of the longitudinal component of atmospheric turbulence are modeled to approximately the same scale as that L1scd to model the building or structurc. The modeled building or other struClure and arc surrounding structures and topography geometrically similar to their full-scale counterparts, except that, for low-rise buildings meeting the requirements of Section 2.07.5.1, tests shall be permitted for the modeled building in a single exposure site as defined in Section 207.5.6.3. The projected area of the modeled building or other Slructure and sUlToundings is less than 8 percent of the test section cross-sectional area unless correction is made for blockage.
5.
The longitudinal pressure gradient in the wind tunnel test section is accounted for.
6.
Reynolds number effects on pressures and forces arc minimized.
7.
Response characteristics of the wind tunnel instrumentation arc consistent with the required measurements.
207.6.3 Dynamic Response Tests for the purpose of determining the dynamic response of a building or other structure shall be in accordance with Section 207.6.2. The structural model and associated analysis shall account for mass distribution, stiffness, and damping.
207.6.4 Limitations
" Gf
~
1+ O.85gep!Q' + /I'
. ...... .. _ - - - - _ .. ........
where
P~ 4.9J75;: (10/ z)""
(207-30)
Q~
(207 -31)
......-.... II~ 0.017 (,".z) J fJ V.
-.'""C~
and
...
III
207.6.5 Wind-Borne Debris
Glazing in buildings in wind-borne debris regions shall be protected in accordance with Section 207.5.9.3. 207.7 Gust Effect Factor for Other Structures
207.7.1 Poles, Masts, and Trussed Towers For other structures such as poles, masts, trussed towers, and the like, that function as communication towers or antenna-supporting structures, electrical transmission towers and poles, structures supporting lighting equipment, and the like, the gust effect factor shall he calculated by
(207-32)
The peak factor g shall be taken as 4.0. The value of e shall be 0.75 for electrical transmission towers and poles other cases. The parameters that with cables, or 1.0 for define the wind field characteristics, specifically Do, a:, I, i', b, and i'i, shall be obtained from Table 207-1 I. The effective height "2 shall be taken as two-thirds the height of the tower eI3h), but not less than 2m;" as listed in Table 207-11. V; is calculated using Eqn. 207-J4.
an
207.7.2 Billboard Structures, Free-Standing Walls, and Solid Signs For billboard structures, free-standing wai!s, and solid signs with height-to-least-horizontal dimension greater than 4, the procedures in Section 207.7.1 shall be used. Otherwise, the procedures in Section 207.5.8.2 shall be used. 207.7.3 Cables Por cables, Equations 207-29, 207-30, and 207-32 shall be used together with: (207-33)
207.6.4.1 Limitations on Wind Speeds
Variation of basic wind speeds with direction shall not be perrnitted unless the analysis for wind speeds conforms to the requirements of Section 207.5.4.2.
(207 -29)
1+ 0.85gp
where B is the total length of the cable.
207.8 Estimates of Dynamic Properties When values for nalUral frequency and damping ratio as required input parameters in the calculation of the gust effect factor for buildings and other structures arc [1'lt available from full-scale measurements of (he ::"1(1:1 structure or from computer simulation, the cst::, •. ' .J formulas given in Sections 207.8.1 and 207.8.2 sh,dl uc used. 207.8.1 Approximate Fundamental Frequency 207.8.1.1 Buildings For buildings, the natura! fre.qucncy III may be llsing the following general formulas:
Association of Structural Engineers of the Philippines
eSlilll ':l ; :!
CHAFfEH ? - Minimum Design I. cads
Type
Service-level
Strength· level
6711z 50llz
56/Jz 4211z
Concrete Sleel
2·33
207.8.2 Approximate Damping Ratio 207.8.2.1 General
207.8.1.2 Free-Standing Trussed Towers and Billboard Structures For free-slanding (russed towers. nnd billboard siructurcs,
For wind loading purposes, the total damping ml io Illay be taken as 0.015 for co ncretc slruclures, and 0.010 for slcel and oiller Siruciures.
(he natural frequency "1 may be es timated using Ihe
207.8.2.2 Poles, Mast" Trussed Towers, Bi ll boards,
following formula:
and Simila r S tru ctu r es Allcrmtl iveiy for poles, masts. trussed towers, billboards,
where
and
,,=107/M , / h " II ,, 1,1 fA " ..
(207·34)
R"u
= 1.25(ItIBor0 2
(207·35)
M
=
c=c
(207-36)
=-,--_.::,3,--_
(207·37)
.
V~
~ 0.003 /J, = 0.16 II where
k
• (0",/ )' +0. 15 / IJ,
I'll = 0.9 for Iri;'lngu!nr (3-legged) towers, and 1.0 for other conditions. A~I = 1.0 for service-level condition, and 0.R3 for strength-level co ndit ion. Bulo is the average tower width, or average of the base and top widths, or no and nil respective ly, fo r tapered to wers. km shall be (aken as 2.6
III
(207·38)
is the serv ice· le ve l natural frequency.
The structu ral dampi ng mlio fl, m stre ngt h·level co ndition for poles, masts, trussed towers, billboards. Hnd the like, may be taken as
~ 0.004 /J , = 0.23 Iz
(207·39)
whe re III is the st rc ngth · lcvc l natura l frequ e ncy.
for billboards, poles, masts, an d non-tapering lowers and ol her stru ctures.
Alternmi ve ly. for frcc- slanding lowers or billboard Sl ruCltirc.s ill the Philippines withoul
Service-level
Strength-level
81/11 91/11
68111 75/11
For antellna towers or electrica l tra nsmissioll lowers in the Philippincs wilh I1mss ratio IIIr a'i 5% (or approximalcl y 3 ilII3Chcd alltennas): Plan.shape SgUiJrC Triallgul:lr
Service- level
8111z 7]111
The aerodynamic damping ratio fJ" at se rvice-l ev:'! condition for lrussed lOwers, billboard s, and the like. In:. be taken ,1S
/J" \vherc
For poles. mas Is. sol id signs, guyed stnJclurcs. cables. and other structures. thc naturill rrc(luellcy mily be estimated from rull -sc ale IllC
0.007
",
~ 0 .007
1207·40)
is the service· level natural frequen cy.
'nlC
~ 0.007
for Wind Zone i or 2.
or for V> 162 kph,
(207·" I)
fl" = 0 .0 11
",
Strength -level 68111 6111z
207.8. 1.3 Pol es, M '1StS, SuJid Signs, Guyed Structures, Cahles, .1IId O ther Structur'cs
/1 1
=
fl. = O.lK~) ~ 0 .007
ror
Wind
", or for V :S 162 kph w here
Zone
3,
(207.· ;.<)
"l is the strength-Icvel na::lr,,1 frcquency.
The acrodYllamic damping ratio /1" Illily be ohtilincd fmm a more detailed analysis with the ilpproprialc hasic wind speed Vas parallle(er. the hourly mean wind speed from E
Nill ional Stru clul',tl Code of lhe Phil i pplrH:!~ (-) :! , Edition Volul'll n 1
2 -3~
CHI\PTE'~
2·· Minimum Design l.oeds
The 100ili damping ratio ,Bshall be taken as
fl =fl, + fl. ,,; 0.06
(207-43)
American Society of Testing and Materials (AS'j'M) ASTM Inlemalional 100 Barr Harbor Drive West Conshohocken, PA 19428-2959
207.9 Consensus Sland:t ..ds a nd O lher Referenced J)(IClIlll c n(s
This section lisls the consensus slandards and other documents which .Ire
section :
adOp(l~d
by reference within thi s
Assor..iiltion of Stru ctural Enginer:m.; of the Philippines
CHAPTER 2 - Minimum Design Loads
®
®
®
@
©
©
-.... Transverse
-....
Longitudinal
WALLS AND ROOFS Note.s:
2.
3. ,I. 5. 6,
7, R
Pn·_~SItH·.f ,\'/10""1 (11'(, applied (0 I/:e /101';:011101 fllld n~rlical proiectlO/l.s. for ('xpo.ntl"(' n. ell Ii =- 9 m. I .. = I ,f), om! K" ~ J.0. t ft/iust /() mile!" t'omlilious usmg Equalioll 207-1 , 111l! (oad pa[Wr'II.f ,tltOlt'1I slwll he applied 10 ca(," ("orner of/he building ill lui'll n.t the reference c
e'"
oj 1\'0/1
C - In ferior 1011(' O/ lI'CJII
IJ ., 1;'1/{1 :one (~rrooJ
D - I nferior W il l! of roof
A - t.:' ld w ne
y, /0,
V('rl h'o//m'sslII'c Z(JII("f - N e! (.~lIm O./ill /I 'nIa} lind eXl er/lfIl) pres,wrl's 01/ horizonlo! projali(U/ (~f' E - /;'m/ :!OII(' of lI'i"dl\'(lr(/ roo/ G - 11I1('rior 10m' 0/ wjllt/ward rmif r -, /;'1/(1 ZO/l(' o./il'cward roof I I- Inferior zOlle o/It'cword 1'00./ 11'11,'1'<' =01/1' I~" rlr (J /il/I,\' /Ifl (/ nJ()/ overhang on the windward ,tid,' of thl' /milding, U,H' Emt (111(/ G OII for the prt~,nllrt! /lOri:OIl(lIl jlJ'(Jjl" IUJl/I!f lire (wC'r /tmrg, OverJumg,{ (III ,he I('cwftnl (IIUI,fitle edgt',f shl/II hal'(' ill(' luuir :Of/(' prl'~.flln> (fJlJ'Ii~'d, NmfllioJl:
II +,
II/{·
If) IIl' I'('l'lrl II} le/ul horizontal di"'(~J/sioll or f) 411, whic/rel'f!r i,f slII/IIft,,-. hrt! /lilt I('.{,r ,11m/ ('il/lrr 4% HI it'U,I" /lIJri:mll(l1 or 0 , 9111 , ML'(II/ rmd'/lI'iglil, m, ,'X('('pi ,hal em'e I!n);"/.fhalllw !ls('dln/' mq((lIIgit·x < In°, AlIl::le (?(,,//IIi(' (?(r()t~{Jhll" '10";;11111(/1. degrc('5,
tlilJJ('II,1'flnI
e
011
Figure 207· J Design Wino PrcsslllcS on Wall s and Roo fs of Enclosed Buildings w ith h"; 18m, Main Wind - Force Resisting System -- Method J 1h
National Stru ctural Code of the PI1ilippin es 6 Edition Volum e 1
2-35
2-36
CHAPTEF< 2 .-. Minimum Design Loads
Adjustment Factor for Building Height and Exposure A
..__.
_
Mean roof height (Ill) 4.5 6.0 .. 7.5 9.0 11.0 12.0 13.7 15.2 16.8 18.0
--~
~
..-.---,.
B
-~-.-.-
-~~-.---.~-
-.~-
1. 00 1.00 1. 00 1.00 1.05 1.09 1.12 1.16 --_._._--1.19 1.22
Exposure C D 1.21 --.. . 1.47 1.29 1.55 1.35 1.61 1.40 1.66 1.45 1.70 1.74 1.49 1.53 1.78 1.56 - -1.81 --1.84 1.59 1.62 -~~ ~
-~~--
WALLS AND ROOFS
Basic Wind
Roof
Speed
Overhangs
Vcrtical Pressures, kPa ...
-~
_..._ - -
---
(kril)
E
F
G
H
Eoil
G Oh
ISO
-0.79 -0.79
-0.45 -0.48
-0.55 -0.55
-0.35
-1.1 I -1.1 I
-~
-0.37
-0.79
-0.52
-0.55
-0.40
-1.11
-0.87
25
-~-------
250
..-
30 to 45 -.----.----~~-
o to 5
-.----~--
10 ._.._._---_15 .•. _-_.
20
Figure 207-2 Design Wind Pressures on Walls and Roofs of Enclosed Buildings with h $; ! 8m, Main Wind-Force Resisting System _. Method I Association of StrlJcturai Engineers of the Philippines
-0.87
CHAPTER 2 - Minimum De sign Load s
Flat Roof
Hip Roof (r
Gable Roof (0::;7") [
-]
2-37
•
Interior Zones Rook· :zoo. 1 I w.... . z.on. "
Gable Roof (7°< 045°) . . . Corner Zones
End Zones
I!!III
RcloOf• . Zone 21 Waite · Ion. 15
~ . z.oo. 8
WALLS AND ROOFS NOles:
,_
Pn's."ul'I' sholl''' art! applh'ti llorll/(//Iu ,11(' .\'/Irftu:e. for ('XI'(/,\ /I/"(: /J.
Eqllllfirlll 207· 1.
flf
h ""· 9111,
I~. <.~
1.0. and K:. = 1,0, A ((jll.tf 10 of/WI" cclIJdiljolls IIsing
.
l'llis (lm/lllinlls siN,II'v .I'igllf/j' pressu re.l" (/eli,,}.! 10 1l"(/ l'd (l ml (tIl'IIY from {he .vllif aces. I'f!spec lil·/' /y.
3. 4.
FOI" hip roo/i' wilh
e::; 25°. lone 3 shall he 11'l'11I(~d as lOll e 2.
For 1'{li'l'I i" I' I"ind {/I'f'(I.I' h<.'/ \\ '(,(,II (hose ~ i \'(m . \'o /lle may he "lItl'l]l o/a(('d, o{/!('rwiSI' IIS(, fhe 1'' ','lI(: a,\'socia/ed will, (he lower e!ll'cli\lc wind (/r('C/.
5_
Nllffllhm : 1/ ' "
II} pern" 11 oj lellsi horizol/tlll n.9111.
dim"/Is ;oll 01"
()Ab. 1\"/tidw l'('r is xfI/(/lIer,
bill 11111 I(':ro,f
dum (, j/her 4 % o/ll'dS! horiZ(}lIIul dimel/sio/l m '
11ll{1t6glt!. III m. I'XC'('/l1 thllt C'dVi' h (·I.~hf shalf ht' lI.w ·dIiw rO<~(lI /1glf!'" < /0°, All}.!'!' n/p/ml(' u(l'(wffrl)/11 Iwn:rJ/lIUI. rlt'W'j'I '.r,
"
•., M('(II1
n
=-
Figu re 207~3 Design Wi nd Pressures on Wa lls & Roof of Enclosed Bll ildings with II S I R Ill , Componen ts and Cladd ing - Meth od I th
National Struc tural Coda o f th e Philippines 6 Edition Volume 1
,.
2-38
CH A PTEF~
2 ._. Minim ul11 Design Load s
Adjustment Factor fo r
B til·Id·lO gs II. eIgHt · I an dE:. xposure, Ie Mean roof Exposure heigh! (m) B .. C 4.5 ."_M•. 1.00 1.2 1 6.0 1.00 .1.29 1.00 7.5 1.35 1.00 9.0 l AO 11 .0 1.05 IA5 1.49 12.0 1.09 13.7 1.12 1. 53 15.2 1. 16 1.56 16.8 1.1 9 1.59 1. 22 1.62 18.0
D I A7 1.5 5 1.6 1 1.66 1.70 1.74 1.78 1. 8 1 1.84 1.87
WALLS AND ROOFS Ne! Desig n Wind Pressure, /J'Kh kP" (Exp osu re 13 at " =I0 111 with 1= 1.0 and Kd = 1.0) Effective Roof Basic Wind Speed V (kph ) wind Ang le Zone area (0) 150 200 250 (m' ) I I I I 0<0 <7
--
1.0 2.0 4.5 9.5
2 2 2
... - -- 1.0
2
9.5
3 3 3
1.0 2.0 4 .5
.l
9.5
- 2.0 4.5
0.3 0 0.29 0.26 0.24 0.30 0.29 0.26 0.2 4 0 .30 0.29 0.26 -"._"_._ 0.24
-075 -0.73 ·0.71 -0.69
0.55 0.51 0.47
0044
0.55 0.51
OA7 OA4
-.......:L~ ___..0 55 - - ._- -0.55
0.67
-2 .09 -2.03 -1.96 - 1.91
.. -3.50 -3.1 3 -2.64 -2.26
0. 85 0.79 0.73
-0. 8 1
0:44
OA4
0.85 079 .. 0.73 0.67
-1.90 -1 .57 ·1.1 4
0.55 0.51 0.4 7 0.44
0.55 0.5 1 0.47 0.4 4
0.85 0.79 0. 73 ---0 .67
-I. I 2 -0.95
.---- ----0.81
0 .5 1
0047
0.5 1 0.4 7
-
-5.27 -4.37 ----3.1_..7,--
Figure 20 7· 3;). (co l1t 'd) - Design Wind Pressu res on Walls & Roo f ofE tlc loscd : l3 uildings with It 5" 18 Ill , Components and Cladding ... Me thod I
Associa tion or S(ruClllfaJEngineers of the Phllippill!'!S
-2 .26
CHAPTER 2 - Minimum Design Loads
Net Des ign Wind Pressure, POOh kPa (Exposure B at II =10 In with J = 1.0 and KJ = 1.0) Effective Roof Basic Wind Speed V (kph) wind Angle Zone area (deg) 250 150 200 (m') I I I
1.0 2.0 4.5
O.4J 0.40 0.34
-0.69 -0.67 -0.64
0.78 0.71 0.62
0.78 0.71 0.62
1.20 1.10 0.95
-1.9 1 - 1.86 -1.78
1
9.5
0.30
-0.62
0.55
0.55
0:85
-1.73
2 2 2
1.0 2.0 4.5
0.43 0.40 0.34
-1. 20 - 1.10 -0.97
0.78 0.71 0.62
0.7 8 0.71 0.62
1.20 1.10 0.95
-3.33 -3.06 -2.71
2
9.5
0.30
-0.88
0.55
0.55
0.85
-2.44
3 3 3
1.0 2.0 4.5
0.43 0.40 0.34
-1.77 -1.65 -1.50
0.78 0.71 0.62
0.78 0.71 0.62
1.20 1.10 0.95
-4.92 -4.60 -4. 18
3
9.5
0.30
-1.39
0.55
0.55
0.85
-3.86
1 I 1
1.0
0.69
2.0 4.5
0.67 0.64
-0.75 -0.7 1 -0.66
1.23 1.20 1.1 5
1.23 1.20 1.15
1.91 1.86 1.78
-1.98 -1.84
1
9.5
0.62
-0.62
1.12
1. 12
1.73
-1.73
2 2 2
1.0 2.0 4.5
0.69 0.67 0.64
-0.88 -0.84 -0.79
1.23 1.20 1.1 5
1.23 1.20 1.15
1.91 1.86 1.78
-2.44 -2.33 -2. 19
2
9.5
0.62
-0.75
1.11
1.11
1.73
-2.09
3 - -_ . 3 3 3
1.0 2.0 4.5
0.69 0.67 0.64
-0.88 -0.84 -0.79
--- 1.23 1.20 1.1 5
1.23 1.20 1. 15
1.9 1 1.86 1.78
-2.44 -2.33 -2.19
9.5
0.62
-0.75
1.1 2
1.12
1.73
-2.09
1.0
0.75 0.72
1.35 1.28 1.2 1 1.14
2.09 1.99 1.87 1.77
-2 .26 -2 .17 -2.05 -1.95
e > 7 to 27
0 > 27 1o 45
Wall
-
-2.09
4 4 4 4
4.5 9.5
0.67
-0.78 -0.74
0.64
-0.70
1.35 1.28 1.21 1.14
4
46.5
0.56
-0.62
1.01
1.01
1.56
-1.73
1.35 1.28 1.2 I 1.14
1.35 1.28 1.2 I 1. 14
2.09 1.99 1.87 1. 77
-2.79 -2.60 -2.36 -2.17
1.0 I
1.0 I
1.56
5 ..-.--_.-
". -
2.0
1.0.. -_.•... _--_
-
..
-
5 2.0_-_._.--_. - -5 4.5 -. 5 9.5 --_. 5
46.5
-0.8 1
_-_
-0.26 . 0.72 ~_ .024.. __ "- - 0.67 -0.22 0.64 -0.20 ."-",
..0.75 .
0.56
-0.62
Figurc 207-3h (conl'd) - Design Wind Pressures on Walls & Roof of Enc losed Buildings wi!h " .:S I R 111, Components
Nation;;)1Stru ctural Code of the Ph ilippines 6 Edition Vo lume 1 th
.
-1.73
2-39
2-40
CHAPTE:!, 2 - Minimum Design l.oads
-
V(Z)
Z
vrZ)
Speed-up
V{Z)
Z
X(Upwind)
X (Downwind)
-Spe
X (Do
~~-
•
Hil
ESCARPMENT
2-D RIDGE OR 3-D AXISYMMETRICAL H
..-
._--- K, Multiplier
HlL" 0.2 0.25 0.30
ro:-:lS OAO OA5 .0.50
3-0 Axisym.
2-0
2-0
Ridge
Escarp
0.29 0.36 0.43 0.51 0.58 0.65 0.72
0.17 0.21 0.26 0.30 0.34 --0.38
OA7
OA3
0.53
._---_.
K3 Multiplier
K, Multiplier xlI~h
Hill 0.21 0.26 0.32 0.37 0.42
0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00
All Other Cases
2-0 Escarp 1.00 0.88 0.75 0.63 0.50 0.38 0.25 0.13 0.00
..
1.00 0.67 0.33 0.00 0.00 0.00 0.00
_-_. -~ 0.00
---_._-
2-0
zlLh
Ridge
2-0 Escarp
-.~----
__
I.
For m!l/('.\' HIL,. and :JL,. other {liall (ho.H' shoWI/, lineal' il1lerpolalioll is perm/lied.
2.
IfIL;, > 0.5, (lSSIIIII(, /-1Il.;, ,":0 O.5jbr ('valuating K,l1lJd slIh.I'(i!lIfe 211/or ,.,Jor {'will/Olillg K., alld K.lMliltipli('rs al"e based 011 rhe (lSSl/lI1ptiOIl rllal approoches 1111' hill OJ" escarplII(,lI( a/ollg fhe dircctioll oj"maXi/llllfl1 stope.
4,
{:O/"
Nolafion"
!l '" lIeighl o!"hifl or escalpmellt re/(I{il'(' 10 Ihe IIpwind /erroill, III, /,1, c, /Ji.v/ollce IIfI\\'illli o(eres/ (0 where (he d((rerence ill g/'Olind del'atioll is hal(thc heighl o(lli/! or K I ~~ "-oclor 10 (U'COIIIl(./(){" shape
:~
Axisym. Hill _._
1.00 1.00 1.00 0.00 0.67 0.10 0.74 0.78 0.61 0.45 0.20 0.55 OA7 -- .. 030 030 0.41 0.37 0.20 .0.40 0.30 0.22 0.29 ._-- - -0.14 0.50 ----_ .. . -----0.09 0.17 0.22 ..- --_.0.60 0.17 0.06 0.70 0.12 0.14 0.09 0.80 - ,0.04 ,--0.11 0.03 0.90 0.07 1.00 0.08 _._ .._0.02 .. _---~ ---_. 0.02 0.00 0.01 1.50 (1.00 0.00 0.00 2.00
NOlt'S:
J.
3-0 -.-
('.I·CU/"PIIH'II/, II!
j{orizon/ol aflcl/I{(IfiOIl flu'for.
/" ., lIeighl alll'/!II(1lionfllC/ol".
Figurc 207-4: Topographic Factor, K/I _. Mcthod 2
Association of Structural Engineers of the Philippines
CHAPTER 2 - Minimum Design Loads
Equations:
K, determined from table below
II ,f
Parameters for Speed-Up over Hills and Escarpments K,I(HlL,,) Hill Shape Exposure Upwind )' of Crest D B C 2-dimensional ridges (or valleys 1.30 1.45 1.55 1.5 3 with negative H in K,I(HlL,) 2-dimensional escarpments 0.75 0.85 0.95 2.5 1.5 3-dimensional axisym. hill 0.95 1.05 1.15 4 1.5
I'
Downwind
Figure 207-4 (cont'd): Topographic Factor, K" - Method 2
NJlionn! Structural Coele:: of the Philippines 6 Edition Volume 1 111
of Crest 1.5 4 ,
1.5
2-4 1
2-42
CHAPTER 2 - Minimum Design Loads
Enclosure Classification Open Buildings Partially Enclosed Buildings
.. Enclosed Buildings
Ge, 0.00 +0.55 -0.55 +0.18 -0.1 8
WALLS AND ROOFS
NOles:
I.
Plus and minus signs s ign ify pressures acting toward and away from the internal sUI/aas. respectively.
2. 3.
Values of GCp' shall be used with q, or q" as specified in Section 207.5.12. Two cases shall be considered to determine 'he critical load requirements for the appropriate condition: (i) a positive value ojGCpi applied to all ifltemal sw/aces (ii) a Ilegative value o/GCpi applied to all internal sUl/aces
Figure 207-5 Internal Pressure Coefficients, GCpi on Walls and Roofs of Enclosed, Partially Enclosed and Open Buildings for all Heights Main Wind-Force Resisling System/Components & Cladding - Method 2
As sociA ti on of StruCILJfal Engineers of the Philippines
CHAPTE R 2 - M inlll1l1lll Design
PlAN
Loads
2-43
ELEVATION
GABLE, HIP ROOF
-_ q,r;Cp
1-
L
ELEVATION
ELEVATION
MONOSLOPE ROOF (NOTE 4)
q"Gc"
L----
L
PLAN
L
----J
ELEVATION
MANSARD ROOF (NOTE 8) WALLS AND ROOFS figure 207-6 External Pressure Coefficients, C" on
Wal ls and Roofs of Enclosed, Partially Enclosed Buildings for all Heights Main Wind-Force Resisting System - Method 2 Nation,)1 Structural Code of the Pililippines 6'" Edition Volum e 1
2·,44
CHAPTEH 2 -- Minimum Design Loads
~---
Wall Pressure Coefficients, C LIB Co All values 0.8 0-1 -0.5 Leeward Wall -0.3 2 >4 -0.2 Side Wall - - - Ali values -0.7 Surface Windward Wall
Usc With Ci,
q" Oil
---------------,-_. RoofPrcSSUfe Coefficients, C" fOf use with
-
Wind Direction ----_.
-~-~--
Normal to ridge for () < 10 and Parallel to ridge for all 0
_..._------
----IT<-~)
-
hlL
_ _ "m
Leeward
Windward
Angle, () de )rces Angle, IJ Idegrees) > 60 10 10 15 >2 a 45 IS 20 10 25 30 35 --_. -0.7 -0.5 -OJ -0.5 -0.3 -0.2 -0.2 -0.6 0.0· ::: 0.25_.. -0.18 0.2 0.3 0.3 0.4 0.4 0.010 --05 -0.5 0.0 • -0.9 -0.7 -0.4 -0.3 -0.2 -0.2 -0.6 0.5 -0.18 ._-.:2.lL _ 0.0' 0.2 0.2 0.3 0.4 0.010 --1.0 -0.7 -0.7 -0.6 -OJ -0.2 0.0' -0.5 -0.6 -1.3 ** 0.0 • -0.18 :: I.Q_ -0.18 -0.18 0.2 __ ~ 02. __ 00111 ... Horizontal distance from * Value is provided for interpolation purposes, Cp - windward edge o to hl2 -0.9, -0.18 ::: 0.5 hl2 to II _ -0.9,-QJL 1-------.. II to 211 -0.5, -0.18 ** Value can be reduced linearly with arca over > 211 which it is applicable as follows: ---_.-0.3, -0.18 Reduction Factor Area 1m') . . .1.3 •• , -0.18 to h12 < 9 1.0 .. _-._1.0 23 0.9 ---------,-_._---> h/2 -0.7, ·0.18 > 93 0.8 ---,-..- ----- -----." .... ,.,--------------..-----.
~.--.-,----
Normal to ridge for () :: 10°
Cfll
0"'0*
~---
-----~
__
o
'"
------.-----~.,---.-
"
-.---.-~
WALLS AND ROOFS 1.
2,
3, 4. 5, rI. 7,
FIllS alld lIIillllS sigl1.\' sigll({I' pre,I'slIn's (lcling IOw(/rd (llId (1\\'oyJi'ollllhe .I'll/fixes, respeclively, Linear interpolalion is permil(edJiJr value.t (~f LIB: hlL (llId () othel' Ihall shown. Interpolation shall only he ('wTied out b('tween )lo/ues o(the salll('.I'i Where no valu(' o(lhe same sigll is given, assume O,OIbr illl<'I]JOlalio/l purposes. Where 111'0 values ()I(~, are fisled, {hi.\' illdic(lies Ihal the windw(lrd roofslope is subjecled 10 eilher posilive or lIegalille pressures (lnd Ihe r()(!(SlnlCI, shall he desigllcd/i:n- bOlh conditiOlls. II/IC'/potalioll for inlermcdiale ratios olhlL ill Ihis case shall ollly he carried oul belweel/ (~, l'allle,l' (~f like ,I'(f!,11 For mOllos/ope roo/i', {,lIlire rQ(~(,wljiJce i,l' eilher a windward OJ' leeward sill/ace. Forjlexihfe huildingl' 115e appropriale G, a.l· delermilled by Section 207,5,8. Reier 10 Figure ]07- 7(i)r dOilies (llld Figure 207-8(i)/' arched /'oof~ NOlalion: fJ ~ I IOl'i20nla/ dimension o(/Jlli/dillg, ill m, IIlNI,wred normal 10 willd direclioll L Iloriwlllal dimC'nsion of buildillg, ill m, measured paJ'alfd 10 wind direclioll. 1/ M('(l1I r()(?( heighl in III, ex('c/ilihol ('()I'(' heighl ,dl(dl hI' us(,d/or 0 :S /() degn't's, I- ,-- lIeighl (lho\!(' grollnd. m. (!
,\'
III
GII.I'I
{:IT('CfJiICIOI'
({:, ,qlo VelocilY pn'x,I'lII'(', Nlml. ('wlll/llled (II /'("I,/)('Clilll' height. f) Angle ofll{(lJI{' o(roor(rolll horizonlal, degrees. For IIWll.Hlnl roo/i'. the lop horiuJ!/1a1 sl/rfrU'(' (llId feew(Jrd il1cfil1('(/ Sll/jiU'1' ,I'half 17(' Irealed as lecw(lrd sllIjiwes/i'olll Ihe lah/(', Fxn'jlls/ilr MWFR,<,,' ',I' ollhe l'oo(co/lsiSlillf: (~/mo/JIelll /'c,I'islingfmlllcs, IiiI' 10101 horizonlo! shear shalf 1/01 h(' 1("I's Ihll/l Iha! d('/erlllilled hi' Ii,', '('('{il willd(hrc('s Oil l'oo(,wr(ace,I'. For mo/slopes gn'lIll'1' Ihal! 80", II.1'C (~, 0.8
Figure 207-6(cont'd) - External Pressure Coeflicicnts, e p on Walls and Roofs of Enclosed, Partially Enclosed Buildings [c)r all Heighls Main Wind Force Resisting System -- Method 2 Association of Structural Engineers of the Philippines
CHAPTEF~
8
I·
·1 A (h 0 10 =025)
'\
A (hoID=O) \ +0. 8
1\
+0.4
~
~
V
~
;;;-
~ 7~
/
/
7 /
" ----- ____ "" ,-- ----::::. -/-,
\
>!
1/
/ \
~1,6
,,
/
,
"
A (holD 2: 1.0)
C (h"ID=O)
/
/
,
----
/ V
1/ ,,
2~45
:?J'l --0
o
+0.'
2 -- Minimum Design Loads
/ "I, - -j-/
C (holD 2:0.5)
,
~
"~ V
--- -
B (h"ID=O)
B (hoID2:0.5)
--~
V
~1.8
1
0.1
0.2
0.3
0.'
0.'
Ratlo of Rise to Diameter, flO Noles: 1.
2. 1.
5. {i
7. 8
Two load cases shafl be considered' Case A. C,. l'{Ilucs between A and Band belween IJ arid C shaff be dl~/erll/il/ed by linear interpolalion along arcs 011 (he dome parallel 10 rhe lI'illd directioll; Case B. C" shall be Ihe cons(anl value of A/or ():5 25 degrees, and shall be determined by linear intelpolalion/i"Ol11 25 degrees 10 Band from B 10 ,.
Values del1o(e C~, to /;I~ used wilh q(ho ~-/) where hI) +fis the height al the top 1~{tlW dOllJl'. PIlls and millllS signs signijj' pressures acting toward alld away/rom the sw:{acl's. respectively (~, is COllstall1 0/1 the dome slIrfilCefor orcs o(cirdes perpendicular to fhe wind direction; /or ('.wmp/c, lhe (lrC" jills.I"ing Ihrough IJ-/J,/J and a/I II!', p(lmlld 10 B-I1-/1, " For wI/lies o/Ir,lD IW(I\·eell{flro.I'1' hl"led on Ihe graph ('UI"I'('.I', 1i1l('(J1" illierpo/a(ioll sha/l be j1amil(l'd. (I = 0 degrees on dOllie spring line, () ~, 90 degrees af dl)lIIl' cellter fOp point, lis measured{rom spring lilli' {o fop The 100al horizol1(a/ shear shall !lot be less (hall that delermined hy netlecting wind(r)/"(YI' all ro(lsJII/ocl's For/1D value'S /I'SS (hall 0.0.5. lise Figure 207-6.
'Figure 207-7 External Pressure Coefficients, C~) for loads 011 Domed Roofs of Enclosed, Partially Enclosed Buildings and Structures for all Heights Main Wind- Force Resisting System ·- Method 2
th
National Structural Code of the Philippines 6 Edition Volume 1
2·46
CHIIPTE H 2·- Minimum Design Loads
ARCHED ROOFS Conditjons Roof on elevated structure
Roof springing from grou nd level
.
Rise- ta-span ratio, ,.
C, Center half
0 < ,.< 0.2 0.2 < r < 0.3 • 0.3 < r< 0.6
Windward quarter -0.9 1.5,. - 0.3 2.75/'-0.7
-0.7 -,. -0.7 - r ·0.7 - r
Leeward quarter -0.5 -0.5 -0.5
0<,.~0.6
1.4,.
-0.7 - ,.
-0.5
Wlrell tlse rise-Io-spar! ratio is 0.2.$r:S 0.3. alternate coefficients given by 6r-2.1 .thoU also be used/or ,he windward Quarter.
Notes: I. 2.
J. 4.
Values listed are/or Ihe '/cferminOliOIl oj average loads all main wincl force resisting systems. Plus mId mimi.! signs Signify pressures actillg IOlVord and alVoy from the sill/aces. respectively. For wind directed pamllcllo the (lxis oJlhe are/J. use pressure cocjficiellfsfrom Figllre 107-6 with wind dil'e('(ed parallel 10 ridge. For components and cladding: ( I) AI roo/perimeter, use Ihe exlemal pressure coelJiciellls ill Figure 207·/ ,lI'ilh 0 h(Jscd on spring line slope and (2)/or remail/ing roof areas. lise exlernal pressure coefflcielJ(J' of this table mrdtll)/ictl hy 0.87.
Figure 207 -8 External Pressure Coeffic ients, Cp for loads on Arched Roofs of Enclosed, Partially Enclosed Buildings and Structures for all He ig ht s Main Wind- Force Resisting System/Compo nents and Cladding - Method 2
Association of Structura l Engineers of the Philippines
CHAPTER 2 - Minimulll Design Loads
2·47
O. 75P >'Y
0. 75Pwx
CASE 1
CASE 3
'I
0.563P"", 0. 75P"",
MT ~ 0. 75 (p"" + Pu ) Bx ' x "" = ± O. I5B x
MT = 0.75 (P",,+ P.r) B T. ,
e, -
,1
,,---r-r-r-,-,
I'-1- r- -r- -1~rT- r- r-t-'
0. 75P"
0. 75Pwx
Br
I'
0.563 P,.J( 0.563 Pwx L-L -.L...l-...L.....L...J·O•563 Rr-r MT = 0.563 (Pwx + PIX) Bxex+ 0.563 (Pwr + PH) Brer
± O.15B,
CASE 2
CASE 4
Case 1. Full design wind pressure acting 011 the projected area perpendicular to each principal axis of the structure, considered separa tely along each principal axis. Case 2. Th ree quaners of the design wind pressure acting on the projected area perpendicular to each princi pal axis of the structure in conjunct ion with a torsional moment as shown, co nside red separately for each principal axis.
Case 3. Wincl loading as defi ned in Case 1, but considered to act simultaneously at 75% of lhe specified value. Case 4. Willd loadi ng as defined in Case 2, but considered to act simultaneously at 75% of the specified value. NOll's '
1.
/){'.~igll wind pre.Hures/n/' windward and Ic('word fa ce.( slta" be d('lcrmilJcd in a/'{'on/ rlllct! wilh IIII' provi.riolls o(Sec/s. 10 7.5. 11.2. 1 {1m/ l fil. 5.ll.l . .l (IS (lflplirah/e l or buildings 01 (Ill hcighlJ. /Ji(lj.!I'(/I".~ .f/lOlI' plan vi{' w'f olh/.i/dins:.
J
Nolo/iflll :
I.
dc.rigll fln's.W/l'e (JCfi11f; ill Ihe x. y prillC/lm/ (lxi.f. n·spl'(·f/\'('~)'. /. ('('lI·ardlucl' d(·,\' i~1I pre.uw'(' fiNing in tlu~ x. y prine/jNII (lx i..-. rt!.ljJt'ctively. (' ((' 1', ('1) -- /;'c'('('II{ricity/iw liJe x, y prillcil)(l{ (lxis oJtl1t! structure. f'(!.\pt:cliw ()'. A"I ,- TO/ :~il/lJiI! /IIOIII/'Itt pel' IIl/il heiglrt (lClilll,: abolll a \'l'rl/ca! axi.~ Il/lhe blli/ding. Por I'
I'll)
PI r P I1
~. Willi/ward/aCt!
' ;'
Figure 207·9 Design Wind Load Cases for All H eights Main Wind-Force Resis ting System - Method 2
Natlonat Structural Code of lI,e Philippines 6·· ' Edition Volu me 1
2·48
CHAPTEH 2 ... Minimum Design Loads
,
......
(~ ./ ..•...
...
•... ,-....
...
•~ .. 0
«)
o
-- ,
"
«)
/ ..
/ ~~
o
~.~
.~
Transverse Direction
c
(j)
....
Longitudinal Dlrectlon BASIC LOAD CASES Figure 207·10 External Pressure Coefficients. Ge,.on Low· Rise Walls & Roo[, of Enclosed. Partially Enclosed Buildings with" ,; I R m. Main Wind· Force Resistin g System ·· Method 2 I\ssoci8\ion of Stru ctural Engineers of 1118 Pililippines
CHAPTER 2 - Minimum Design Loads
Roof Angle 0 (degrees) 0-5 20 30-45 '----90 ...
2-49
Buildin Surface I
2
3
4
5
6
IE
2E
3E
4E
0.40 0.53 0.56 0.56
-0.69 -0.69 0.2 1 0.56
-0.37 -0.48 -0.43 -0.37
-0.29 -0.43 -0.37 -0.37
-0.45 -0.45 -0.45 -0.4 5
-0.45 -0.45 -0.45 -0.45
0.6 1 0.80 0.69 0.69
-1.07 - 1.07 0.27 0.69
-0.53 -0.69 -0.53 -0.48
-0.43 -0.64 -0.4 8 -0.48
-
No!l'.\" :
I. 1.
PIII.~ om' //lilli/X signs signiJjl pr(!.\'slIrc:.' (K/illg (oward and (Ill'oy/rom Ihe slIrjiu.y!.f, re.rpeOillcly.
3.
711(' bllildillg must be designed for all wind directions rising Ih(, R loading patterns .f/IOWI/.
For l'(lIU1~:"
%
ImiMi/1; {:orlll'r
4
other thl/1/ ill turllS
11m.\'(:
show". iiI/cor illfl'lpolofiolJ ;.1' pCl'lllif((!(J,
nil! load pllltems
are applh·t! 10 l'lll:h
as tile Reforellce Corner.
Comhil/o/iOlls o.f eXlema/ IIml illlcmal pre.ts/m!s (see Figure 107·5) shall be evalllnted a.f reqllired 10 obtain lite mOM .revere londings.
For 111(' torsional/Dad cases showlI below. the pres.tures ii, lOlles desiglltl/ed wilh a "'" (1 T. 2T, IT. 4T) shaff be 25% of Ihe full desigll willd prC.fsures (zolle J. 2. 3. 4). 6. £xce}Jlioll : Qlle -"ton'), buildings with len Ilion or equal 10 10 III buildillgs fWO slories or less framed wilh light !rollle CO lls/mel ion. lIIul huildillgs fwo swries or Jess dcsignated willi fll'xible diaphragms lIeed not be designed for Ille larsiOllof lond cases. 7. TOl'siall(lllomlillg sha/J apply fa of( eight basic load palle,."s 1I.<:illg Ih e figllres below applied at cflch referellce comer. 8. Excepi for momt!lII.resistillg frames. tile total horizonlal sllMr shaJl IIot be less Ihon Ihat determilled by lIeglecting willd farces 011 raul sllI/ace.f. 9. For the (/t'.<:ign of tfte MWr"RS providing laleml rt'Sislanc(! i" a dil'eCli(J1I parallel f() a rit/ge. lille' orlor flat roO/f. lise 0 =- 0 0 atld loca/e flte la/IC 213 boundfll)' (// rhe mid·lcl/glll olthe Imildillg. 10. The /'oolpr(!ssure coefficicfJ! GC~f. II'hell neg(llil'e ill zolle 2 or 2E. shall be applied ill zOlle 212 E. for a dis/(UJce [ram the edge 0/1'00/ equal 10 0.5 limes (he horizontal dimension 0/ rhe building paml"" 10 Ihe directioll ollhe MWFRS being design ed or 2.5 lim('s Ihe efll'e heigill. hr. at Ihe windward 11'(1/1. whichever is less: lite remainder of zone 212 E. extending 10 {he ridge line .l'lwll usc rhe preSS/Ire coe.Oicienl GC"lfiJl' zone 3/3 e. j 1. No/(uiOIl.' II ~ 10 pl~I,(,(!1/1 (~f Icasl horiZO/lwl dillle'lI.n'OIl or O,4h, which ever is ,fIIf{//"~r. hut 110/ It!!>.\, IIwll eit/wl' 4% (llc(Jsl horiZOIl/(J1 dimem';rm 5.
01'0.9111 Ii
e
MlUJII rno/height. m, except thm eIJl'(~ heighl slllJlI be uset/forO :; I(YO = Angle alp/one ofroo[from horizontal. degrees
<:
@
Transvel se Direction
On!£Ilt'LJdlnal Direction
Torsional Load Cases LOW-RISE WALLS AND ROOFS Figure 207- 10 (conI 'd) EXlernal Pressure Coemcien'" GC"ro ll Low-Rise Willis & Roof., of Enclosed, Partia ll y Enclosed 8uildings \~ilh II :5' 18 m, Main Wind-Force Resistin g System-Method 2 1h
National Structural Code of the Philippines 6 Edition Volul11 e 1
).··SO
CHAPTEF{ 2·· Minimum Design Loads
c.
-1.8
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-1.4
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o +0.2
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+0.4
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~
+0.6
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+1.2
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o
J.-- c--
+0.8
w
L----- I----"
0&(5) 0.9
0.1
1.9
4.6
k- -
9.3 18.6
..-
-
46.5
Effective Wind Area, m
2
WALLS NOles:
1. 2
3. 4. 5. ()
Vertical scale denotes G(~ 10 be used lI'illl q;,. Horizontal scale denotes effective lI'illd area, II!" PIlls and lIli/IUS signs sign!()' pres.l"Ures acting toward alld away/rom the swflees, respectively. Each compOllell! shall be designed/or /l/aximulII pO.l'ilil'(, and !legalil'!' pressures. Jia/!I('s oJG(~Jor wol/s shall be reduced by 10% when 0::; If)" NO((J(ioll:
,~ 10 percellt of !(,II,V! horizontal dimellsioll or (JAil, \Ihic/)el'('r is sma/la. hut 110t less lholl either 4~-{' {~/ least horizontal
(I
II
dimensio/1 or (), 9 III Meall J'()(!/heigiJf. III, except {hal {'(lve height shall he IIsed/llrO ::; 10" C~ Angle (!fplonC? o/n)(!f/rom hori;:oll/(//. degrees. C"'
o
Figure 207-! I A External Pressure Coefficients, Gel' for Loads on Walls of Enclosed, Partially Enclosed Buildings with h ~ 18 In Components and Cladding ~ Method 2
Association of Structural Engineers of the Philippines
CHAPTER 2 - Minimum Design Loads
-14-
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w
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4.6 9 .3 16.6 46 .5 92.9
Effective Wind Area, m 2
-
4 .6 9 .3 18.6 46.5 92 .9
EffacUve Wind Area, m 2
GABLE ROOFS 0 :s t No/e,\".'
2
Vertical ""ale denotes G (~, to be used lI'ilh q~ . lIuriU)lff(l1 scali' denote.\" "jlee/iI'c! 1I'illd (Ire(} A, m:,
J. 4.
1'111.,' III/(/ mill1/5 sign.~ signify preS.fUI'('S (I eliflg toward lind tlw(ly Ji'om the .wl'f ilces. rt'.,.,u!c'lil'l!ly. hoc" COlllpUIII!1If .f/wl/ be d esiglled for IIl(JximUTII pO.filil'C (l11(/III!J;alil'c pre.HUH'.f.
J. 6.
Ftw bllildings SifC't/ within £.tf}()SIIr(,
7.
Nolcll;,m:
For 0 S 70 ,
II '"
11(1/11(':.
o/GCI'/rom Figure 207·58 .f/mll be used. co/culaled preSSIIt'{'S sh(lll be nllllfil'li::d l~r 0.85
n.
J(}'l~ O//ClI.d IwriU)IIW/ dilll{'II.~iul/ 0/11 .{llIgle ,sf/lm module or I)
It'O,l'f lU}r;u11ltal dilfl(!lIsimr (~rll.fill~/c+.tp(JIr matlll/f! 0"/ II ,., HI"t' hl' I/:1I1 .t/wll b(' /Ised j i/I' () $ 10" W <"' IJIII/dillS !lidlh, /1/
4". wlJiclu'ver is .wwller. hilt lIolless thcm dlher" perct'''! of
/It
(}:" Allgll' ~rp/ml(' c~rroojfrmn Jwn;ontlli. dl'grt>es
Fig ure 207-1 113 External Pressure Coem c ient', Ge" on Gable Roofs of Enclosed, Partially Enclosed Buildings with" " 18 III Co mponents and Cladding - Method 2 National Stru ctural Code of th~) Philippines 6 'h Edition VOl lHl'l8 1
2-51
2·52
CHAP TEr< '2 .- Minimum Design l.oads
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......
4 .6
.
9.318.6
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46.592.9
EffectJve Wind Area, m'
W
EffectJve Wind Area, m'
GABLE/HIP ROOFS
i
<
e s 27·
Noles: I. 2.
J. 4. 5. (j
7.
Vertical senft! dC/JOit's Gel' to be Il,H:d II'llh q~ . lIori:mulIl salle del/ofes eIfective wind area, ill !illll(Jl'~' 1JI('lt" :", III I, sigl/s signify p""ssw 'cs (Iclillg IOlI'ord (lml (lway/rom III(' .wlI/nC('.f. r('.o:pf'("(jW/),. E(u:h component .{Iwl( be dl'SIgllcd fnr fllllximlim pn.nfil'(.' (lnd " ego/ille I'res,u/I"(·s. Vallles t!fGCpfor roof OI't·rh(lIlg.f il/ell/rle pl'C",r.urre c(1rltributiolufl'om bOlh IIppt'r /lilli/ower slIr{f/(;(·.... edge / r idge sirips and pressllf"(' c()l:fl/cit'llIS {"r ridJ.:.{•.r l!fguh/('d midi- shal/lIppi!' 011 I'uell hip. For hip roo!'; willi 7° < () ~ 1 PillS (llId 1i ! :II11S
r,
/,'or '"i' w l?fr wilh 0:::: 25°. Wile' 3 ,r/mll h<'/rc·u/c·t! II.r ZOI/C' 2 No/a fioll.\·: Il '" If) jlern'lI f ~rf('(lsl hOri201l(liI {1i1ll ('n<:i(lII.~ or (J.t/II , II'hkh{>I'(!" is .H1l11l1er. hilI Iwl !t'ss thall ('illl('l" 1%
'!{ it'rUI
orfJ.9 m
h ,~ Mean 1'(J(!f Jwight. m. ext'ept thtlt ('IH '(! /r etg"l .I·hall be fl.snl jiJI' (}:5 {} ~~ Angle (~f plane f!f 1'01!lfmlll horizonw/. IJ('gl'('{!'\'
f()Q
Figure 207- 1 IC External Pressure Coefficients, Ge" Oil Gable/II ip Root:, of Enclosed, Part ially Enclosed Buildings with II ~ 18 III Components and Cladding ._. Method 2 AssOcitHion of S trlJ cturf:ll Engineers of the: Phil ippine s
"/lri~(mllll dillll'l!..iu;;
CHAr'TER 2 •. Minimum Design Loads
2.. 53
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+- ®r ® -1® @: -@- -:®
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·1.0 0.1
0.9
1.9
4.6
9.3 18.6
46.5 92.9
Effective Wind Area, m'
Effective Wind Area, m'
GABLE ROOFS 27 0 < 0 :s 45° No/es.
I.
Vertical w:a/c dClJotes (j(~, to he IIsed 1I'111t qh
2.
ilorizontal scale dello!es
(~O;:!Cfin)
wil/d area,
III~
Plus and millll.l" ,~igl/s sigf1[{j' pressllres acting {Oln/rd and (1woyji'olll Ihe siujiu:es. respectively.
·1 5.
I:'(/cll cOIIII'0I1(,1I1 shatl he desigllcd/o}" maxinll/III positil'(' olld /lcgalivc pressures Value.l" o( C;C;.jin' mO/OI'er/ulIIgs illclurie pressure cOlllrihulioll.lji·om holh IIpper and lower .l"1II.f(lces. No(aliOIlS· (J
10 percellt O(/CO.I·t /iori::OIua/ dimcllsioll.l· or OAiI. whichl'v('!" is S/II(lI/t'!". hut !lot less thall eithC'r
4% (?f lells! hOl"ium/ol dimellsioll
orO.9111. II '" Meall }"oo(hr'(l;/II. III AI/gIl' ofplul/(, o(mo//i"Ol1l hOI"/;:(}ntlil. d('gr('{'.1
() '0
Figurc 207-11 D Extcrnal Pressure Coefficients, G(~) on Gable Roo(\ of Enclosed, Partially Enclosed Buildings with h $ ! 8 m Components and Cladding - Method 2 Nc)(ional Structwal Code of
lilt)
th
Philippines 6 Edition Volume 1
2-54
CHAPTER 2 -- Minimum Design Loacls
h
/
.'!.i
.-c
II
0.3 to 0_7
w, = 0.25 to 0.7.1 W
/
STEPPED ROOFS Note,I':
011 Ihe
101l'('r/cl'('/
o/jla(, stepped 1"IJ()f.i· ,\"11011'11 ill Figure 2()7· /2, the
::011('
d("I'igllolioll.\' olld prI'SJIII"(' coefficiellts
."/;ml/i "!
i
1/ /J shalf appzv, except lliar at the 1"()(!/~lIp"er 11'(11/ inICl".I'CClioll(s). ::0111' 3 .\'ha// he {reared (IS zone 2 (lnd ZOIW ) shu!! h, 1,'01('(/ t:x ZOIl(, 1. Posifin' wlll/('.\" of GC:~. (,(/110/ to tho.\'{' /hl" walls ill Figur(' ]{)7·j fA sl1r11/ apply (III (he cross·hatched (/n'O.l' sholl'/! in Figure 207-12. 2.
N%/ivlls : h .~ 1.5111 ill Figure 20l· f 2. hllll/Of greater fhall 30 m
h '" Meall J'()(!f height. //I hi ,- hi or II! ill Figure 207-12: II'~ h/ -j 11 :: h, :0: 3 III, h/h ,~ (U /0 0.7 W c", /Juilding width ill Figure }07-/2 W,'''' If / o/" W!or WI ill Figu/"e207/2. If ~' IVI + W., or WI -I We -1- WI W/Il' '" n.25 {0 0.75 o ""' Angle o(plane (!{/"()(?fli·o/11 horizollfal. d('grees
Figure 207-12 External Pressure Coefficients, Gel' on Stepped RnolS of Enclosed, Partially Enclosed Buildings with Ii ,; 18 III Components and Cladding -- Method 2 Association of Structural Engineers of the PhilipPines
CHAPTER 2 - Minimum Design Loads
2-55
,,
:® , , 1 -_._.!!W ---_ __
ELEVATION OF BUILDING (2 OR MOR E SPANS)
PLAN AND ELEVATION Of A SINGLE SPAN MODULE
-
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Effective Wind Area , m 2
Effective Wind Area, m 2
MULTI-SPAN GABLE HOOFS ,vOI,'S:
2
J. .;,
V('/'fical.u'ai,· d('lIf1il'.f Ge" to /1(' /If('t/II";lh 1/. lfor;::OI/W/ sc:a/(· (kllolt'... t1fi.'clil't! wind Ort'll. 11/ PIli!/: 1111(1 mfllllS Jil:tls signify p n 'ssld'C'S (WI llig IOU"m "I' IMd lIu-ay/rom Ihc' .nfljil( es. r,,~p(·cllI't·~, r 1;(1('11 compl}//('III,\'/udl 111' t!('.\·igl1('(! fill' 1/I11.limulllluHifll'l' (lm/III'C(llin' W'('.f,tllrc:S.
/0 0, I'all/t's ofG<'~.lio lll Figwv l1J7-11 shall hi'
5
For (J
6.
Now/iolls: (I ~, If) 1){'n'('II' fllt'asl llOl'i.7(II1I(11 dim(' /lS;OII,\' uta ,~jl/.~:/( '-"'I'(111 IIIod"/(· III' (JAil. It'hidll'l'('1' is SII/(/II.-I', hl/IIIOf h's,\' ,h(/I/ ('iI/wI' 4 "I"'(I,fl/lOl'I:ml/a/ dillll'lI,f/rJ/l of fI ,flll~/I! 'V){}1I /1111(1"1,, Ill' 0. 9 11/ It '" ,\Iewl I'r",/I/(·'I;/II. m . {'X(,I!I" 11/(/1 "c/I' I' h(·j)!hl ,\'!Jall hi' " .H'd/orl}::: IfJ" It' ." IJuiidillg modllll! widrh, 11/
tJ
00
S
If.{j'd
AI/gil' of"It/l/(, ofronf(rom hori:onltll. t/(',I!.r('l',{
figure 207·13 EXlemal Pressure Coe m cicnls, Ge" on Mullisl'an Gable Roofs of Enclosed. Parlially Enclosed l3uildings wilh " ,; I Rill
Componen ts and Cladding ·- Method 2 National Structural Code
or the Philippines 6U1 Edition Volume
1
/w/,( '/'Ilf
2··56
CHAPTE:H 2 -.. Minimum Design l.oads
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K
·1.2
-1.0
'" '" "'---
f---W
-2.6
-1.B
-1.6
-1.5
~
-1.3
-1.2
-1.1
1-0
-0.8
-;
...c:
~
W
-0.6 -0.4 -0.2
0 +0.2
o+---=::,.,
,--------,1
+0.4 +0.6
All ZONES
< +0.:
0.1
0.9
1.9
4.6
9.3 18.6
46.5 92.9
Effective Wind Area,m 2
~w --~
1--1.
MONOS LOPE ROOFS 3" :::: 0 :::: 10" Noles : I.
Verli(."(I/.\"(xJfe denores (;C:~ (() be used with qh
2.
/ /ol"i:olllill sca/I' denoles {!Ueclive willd al"ea A. m·.
3. 5.
PIlls (Il1d minus signs sign(fjl pressures acting IOll'(JI'd 0111/ (j\\'(J.l'/i"Oln the ,I"wfnces. I"especril'e/y. Each compollent shall be designed/c)/" maxilllum posilil'(, (lnd ncgatil'e pressurc.\". For () ~ 3". wl/ues (~rG(~,f/"()1II Figure 207·/ III shoff he u.\"ed
6.
Nolaliolls:
4.
(/ ,- /0 perCClI1 (~lI('asl horizollial dimellsions or O.4h, \l'lIichell('r is .wwf/e/". bur nor le.u dUIII ('ir!!('/" 4 p('I"n'lIl O(l{'(/S! hon21111fo! dilll('II.1"IOII or O. 9 111 II co 1,,'alJe height sholl he uscd/i."ll" ():S /OG W'" /Juilding width, 11/ (J ", Angle ojp/ww o/roo/from horizontat, degrees
Figure 207-14A External Pressure Cocfticients, Gel' on Monoslope Roofs 3° < e ~ 10° of Enclosed, Partially Enclosed Buildings with h ~ 18 III Components and Cladding -- Method 2 Association of Structural Engineers of the Philippines
CHAvn::F 2 _.- Minimum Design Loads
'--.
I~
I
I
(-------------1 I II
"" IdJ
I II
,
I
I I I
I I
I I I I I I
I
I
---~
~ I:
I I I
I
I
.---I----~
:
I I I II I
I I I II I
L _ __ ______ _ __ J
:
CL
U
C)
·l ~
(2J
-2.9
-2~ 1-----1--+":---1-+--1---
:~
CD
I I
"" IdJ
.J'0'ii~~~~=l=+=~ -2.8 i="®
~e ::l
::l
e
C-
as E
S
-2.4 f------I-i-"--',,,I--I--+--l--I
-221----+-+-+-+-r---j-1 -2.01------11--1--+-+-1--- .. .0 ·I! 1-=:----- ---1--+--+-1---1---1.8 r@~----k::,,-+-i. --. - 1 - ·1.6 ·IA -~I- ----1--+--j
"
I---r.;-------·-I~
r------
.1.3
.~1.~ I--{B_l-_--_-~_-_-·-+·,~-~--~--:O·--t~=t'---=·::t=t=!~:H -Ur--··-----I---j).8 - - - - - -- - - - ---I--- - - - - - j ) A -
. C 1 - - - - - - - - - - - 1 - - - -.-
1---
0-·----·----- -- . _- --- -
~2t~~~~t=j:~~j==t=~~ --- m
+0.4 ALLZON"RS
9+--""1 h
Effective Wind Area, m'
MONOS LOPE ROOFS 10" :S 0 :S 30° NOles '
I.
IINliealscll/('
2.
f {orizol/lill
3
I>IIIS lil/d
to hI' IIsed \\-illl q" e{fective I\"illlf al"('(1 A.
dCI/o[('.\" G(~,
.1'('(1/('
del/ole,l"
lIli/IIIS .\·igll.~
11(.
sigllil.i- pres,l"IIl"e.\' (lclillg toward and (/\\·oy./i·olll fire .I'III/OC(,S. res/wclil'ely
4.
each COIII/HIII('111 sh(lll he d(,s(i~lIed/()r mi/ximllll! po.vil/\'e (lild I/egalil'{' prex.I"II/'e.\'.
5.
NO{(J/joll.\'.
If) /)('l"n'lIl o(l('os( /wri::()Iliu/ diml'lIsionl' OJ" O.4h, w/iic/iCI'cr dimcnl'i()11 or O. 9 111 II Mel/II roof'/I('(I!,lir,1II Jj' Iluitdill,!!. lI'ill/h , III o ": Ang/e o(p{(J/1(' 1!/mo(ji'Olll hori::oll/ol, dc,!!.n'I's /I
i ,l' .1'11)(///('1',
hilt 1I01/('.\'.\' thall ('ililc/' 4 pcrcCllt o({ensl horizontol
Figure 207-1413 External Pressure Coefficients, GC~J 011 Monoslopc Roofs 10° < of Enclosed, Partially Enclosed Buildings with II :s; J 8 III C()Jl1pol1cnts and Cladding .- Method 2 111
eS; 30°
National Structural Code of the Philippines 6 Edition Volume 1
2-57
2·58
CHAPTEH 2 - Minimum Design Loads
... ... 4 ~(SPANAI ,
1, , :
1, , '
r--
~
·3.
2
C-
()
:,
Cl
' :
c: QI '0
..;
;,;i j ~i· ··- --®·-·---· --Kr 3:::
IEQI
®
\
-
'"
~
~
-1.2
III III
-1.0
0-
-
"
-1.4
"'.2
~ -~
"-
~
~
.-
-
W
+0.2
o +0,' +0 .•
~
+0 .•
--
@
+1.0
[--®
+1 .2 +1.4 0.1
Elevation of Building (2 or More Spans)
0.9
1.9
-- -
+0.4
+0 .7 +0.6
.-
4.6
+1 .1
9.3
18.6
46.5 92.9
Effective Wind Area, m'
SA WTOOTH ROOFS No r!'!.;
2.
V"/"I;('(t/ scah' dl·II(J(I!.~ eel' to II(' USN} wilh q" Ilm'hul/wl scale clt'1I0Il'S l'ffi:ctil'e wind ort'a A,
J
Plus ali(I millllX ... i~II'<: slf,lI iji' PI'/,.\'SIW<'S I1Clillg f()\~ 'fI,.d (lilt! (111'(1)' /rom Iht.! .l'Ifrf(IC<',f, rl!sp{'Clil'l'(I"
4,
Had, ('0111(10111.:111 shafll)(' 1/(·.\"igIJl'dji,,. /IIt/rimll'" ;10.\";I;l'(.' (1/11/ Fo r" ~ tfJD, I'(tfl/{'S I~r (j(.~,jh )ll' Fi};ur(' 107· // shall hi! IIsed.
II ....
Now/ioll.\': - /0 1U'l'c('tI/ or/('(/.~I Iwri::collia/ dlll/I'IISiml.\· O/'
(I
r/iI1U'II.\'iml or
n 9111
nAIz.
-1.1
-
c: ....
~ x
fl.
-1.6
-
til
5.
-2 .6
\
_. ' " , "" '" '" "-~
•
·1,
--
I,
0)
•
o
.~
@(SPANB.C & DJ
·2.
·1.
::>
. . ! . . .w- - - I
." • ." • .,.•,
r--
\
-2. 0
()
I--
'-
·3.0
0 ) ,i'6 ii"'2
1
------..
·3 .
,:
,, , ,
• • • ·a. ·a.
I
!
®!;
-4 .1
-4 .0
~.--. @i.-----·~m--mf® 3::: __ :
..
3
/wgllfil'c: PH!SSllres .
wll/ ch e l'I'r
is smalh>r. hili 110'
"',u (/1111/ (,i,//('r .f /)('/H'1If o.//('OSI /wri=mllo/
h · MC'a1/ nxifhl'l,l4hl, m. 1',I t'C'Pl lh{lf ('1II.,. Ilt'ix1ilsltllll hI' 1I,\'(·r/ (or 0 S. /00 II' ... IJllilrlmg 11I0r/llit' wit/lh, 11/ () ~ "'''1:1('0./plm/(: fll rao((nml Jwri=Ollwl, t/t'grC'l!s
f'igurc 207-15 EXlcrtl.1 Pressure Cocmeienls,
GC~
on Sawloolh Roofs
or Enclosed, Partial ly Enclosed Buildings with II S 18 Componen ts and Cladding -.- Method 2 Association of Structural Engineers of the Philippine s
In
CHAr'TER 2 -- Minimum Design Loads
Wind
-
f
ho
I·
o
Wind
·1 DOMED ROOFS
External Pressure Coefficients for Domes with a Circular Base Negative Positive Positive 0, degrees Pressures Pressures Pressures 61 - 90 0-90 0-60 ------+0.5 +0.9 GC, ._.- - -- -0.9 - - - - _.. Notes:
I.
Verlical gale denotes
2 3 4 5.
PlU,I" and
(J(~,
to be used I\'ilh (j(h{) + J) where (fit)
+ f) is [he heigh! althe
lOp of lire dome.
in us signs signify pr(,ssures aClil1g /oll'ard and awayjmln IIie SUI/aces, respec/il'ely. Each componeili shall be designed for moximulIl posilive and negative pressures. Values app~l' (o 0::: h,ID:5 0.5. 0.2 'S.jlD:-:: 0.5. () '" () degrces 011 dome spring lillc. () ." 9() degree.\" (II dome celller top pOinf.I is 1I/('(JsuI"cdji'om spring tim' III
Figure 207-16 External Pressure Coefficients, GC;, on Domed Roois
of Enclosed, Partially Enclosed Buildings and Structures with all Heights Components and Cladding - Method 2
National Structural Code of the Philippines 6'" Edition Volume 1
fo
lOp.
2··59
2-60
CHAP1H, 2 -- Mlnimurn Design Loads
·3. 4
'--.....
·2 .8 ·2. 6 · 2 .4
(!)
~
-2.0
®
·1 .6 ·1.4 ·1 .2
-1.0
ROOF PLAN
-<>.8 -<>.6
--fl--
,,,
i'-.
- -'-- . 2 .3
~--
·1. 8
.3 .2
-- -
"
·2. 2
'- fl'
--
'--.....
·3.0
a.
---
®
·3 . 2
U
500
100
10
-3.6
r--------..
'--
"'----
ill
--- ---
hv
'"
· 1 .8 · 1 .6
~
----
'--..... I----
-1 .4
"'---
1.0 ·-o.g -0.7
.0.4
-<>.2
--
o f---.+1l .2 +1l.4
,i ,,, ,, ,
..,
,--
®i
f-@&®
+1 .0
0.9 1.9
0.1
~
@)
J-- j-----'
,
_________ ____ _ "--' _ _ _ _-L-l
WALL ELEVATION
WALLS AND ROO FS Noll'S:
V('rfir/II scale dellOle,,' (;C,./o he IIsed wirh q, or q..
J 3, 4. 5
(, 7, S.
I/on :(/l/w/ snli(' del/Ole:; effeclil'c will/I ar('(1 A. 11/ PIII.~ /lmlmil/l/.f signs ,t igl/W' preHUI'('S ae/illg 10 l1l/lrd fllld (lII'(I),/rom lhl! .nu/rICe-.f . re.~/)(!(, I ;vdy. u'w II: willi JJOJilil'l' v(lf/u's (?fGCr (//1(/ q" wilh /1l.'f,;(llil'C' "lIfm:,,' (~rGCI' hlW/l {'OI/lPOIU'III.f/wll hf' d" .fil:l1I'ti/"rllJ(HinwIII (JO,fllh 'e tlIuJ nC'}:(llil'l? pn'!i.WrI'I', ('v l'Okirillf drt' {or rtk>/r lI'ilh allg/(- 0 :5 10°. For ut/wr roo/III/Kles (lIId J:cmmt'/I)'. u.\"(~ G(~ " III,,('.f/I"OIll Ffl:!ln' l ill- il (II,d l llf,'lId,m l q. lwst'd 01/ ('XI>OSlII'(: ae./im:d;" St'CI;OI/ 107_5 6. , .' 1/(1 jlal"f1(Wf {'I/Imllf} O/" highl'r (i1(11/ {J,Y //I i.r prm'idl'd aroumllhl' p('rim("j'r I~rlh(' 1'(,1II/ lI';{}' f) "5 1(''', :LOlli'} .~/IIIIII)(' /1'('ul('d 1I.\' I.IIm'l, No /(/(;olls :
10/11'1"/'('11/ (!{ft'fI ,\'{ hori: Olllu/ dill/l' ILI-jOU,I', IUll lJOt l('s,I' rhull 0. 9 !II " ;.' Alel/II rOlf/wigh" m, ('x('('pl ,IU/ll'II\'I' IId}.!1I1 simI! III' /1,1'/'11 (or(} ::; IO il ~ ""/g"IIII)(",,(, ground, III (j ,.
r; - AI/}.:/" "(plum' o(mof(Him hO!'l:mtllll t/r};r cc.r
Figure 207·17 External Pressure Coefficients
GC~,
on Walls and Roof.'\
of Enclosed, Partially Enclosed Bui ldings wilh" > 18111 CO lnponcnts and Cladding - Method 2 Association of Structural Engineers of the Philippines
+0.6 +0.9
4.6 9 .318.8 46.592.9
Effective Wind Area, m2
,
,,
...
-
+1l.6 +1l.8
CHAPTER 2 - Minimum Design Loads
L
0.5L
Wind Direction
=>
y= 0°
Roof Ang le, 0
7.5
13
15°
13
22.5°
A
B A
30°
B A B
37.5°
-
A
45"
0.5L
13
-
C NW 1.2 -1.1 -0.6 -1.4 -0.9 - 1.9 -1.5 -2.4 -1.8 -2.5 - 1.8 -2.4 -1.6 -203
0.5L
Wind Direction
<==
Clear
A B A
0
0.5L
Wind Direction y ~ 0 Obstructed Willd Flow Flow C NW CNt. OJ -0.5 -1.1 -0. 1 -I -I 0 -1.3 -1.1 - 1.3 -2.1 0 -1.6 -1.5 -0.3 -2.3 -1.8 -1.5 -0.5 -2.3 - 1.8 -1.5 -0.6 -2. 2 -1 .8 -1.3 -0.7 -1.9
y = 180°
h
~/777//77/,///7 A
0°
L
rLoad Case
2-61
/.T,//// ///77/,////
Wind CNt. -1.2 -0.6 - 1.5 -0.8 - 1.5 -0.6 -1.7 -0.9
-1.3 - 1.1 -1.8 - 1.1 - 1. 8 - 1.2
Wind Direction y ~ 180 Obstructed Clear Wind Flow Flow C NW C NW C N1 0.2 -0 .5 1.2 -1.1 -0. 1 -1.1 -0.2 0.9 1. 5 0 .3 0.8 1.6 0.4 1.3 1.6 1.2 0.6 1.8 1.7 1.8 0.5 0.7 1.3 2.2 0.6 2.1 2. 1 2.6 1.6 I 2.1 2.2 1.7 2.7 1.9 1.1 2.2 2 .5 0.8 1.4 2.1 2.0
Wind
-CN~_ -1.2 -0.6 - 1.2 -0.3 - 1.1 -OJ -I 0 -I 0.1 -0.9 0.3 -0.9 0.4
Notes:' I. ].
.i.
Cm- allti (~L dl'/I/wt III~I JlY('S.rIII"('.~ (C 500/0 blockage). For I'll /lies off) bmw('{'11 7.5 0 alld 45°, linear illtC!'1'oiflliol/ is permiued. For WIllies v/O le.fs l/tall 7. :; .... lI.ft: ''',lIlos/ope roof /0(1(/ cm:Oicit'III ....
PIlls a1l(/ mitlllS sf}.:lI.\' .flgnj[v Im',H"lwe:; acting lUII'llI'd:; iJlld aWlly/rom the top rQ(ifsUliace. I"c.tp('clil'cly.
5. I'i.
All /aod ClI:;t'-$ sholl'lIfiw (>lIdl roof{1/1J:le sholl /It' I//\'(':;{igatl'd Notatiolls:
I.
II
"CO= -"'0
IIwizoll(al (iimt'llsiOIl.r ofrm!{, Meml rim! heighl. m
1Itl'(lSfIlWI
ill lire
a/I)II!!
WII/d direclio/l, m
)' '"" /JJr('cfioll flwilltl. drf,I'I!I'.t
n '" Augle t?{phllll' o/moffi·{)IIIIl()ri;::tmla/. dI'W'('('s Figure 207-18A Net, Pressure Coefficicnts, eN on Monos lope fre e Roofs 8,; 45°,)' ~ 0".180" of Open Buildings
Main Wind- Force Resisting
S~stem
Nationa! Stru ctu ra l Code of the Philippines 6 h Editio n Vo!urnG 1
2-62
CHAPTER 2 - Minimum Design Loads
L
Wind Direction
=> 1=0 0
h
Roof Angle, 0
Wind Direction y _ 0°, 180° Obstmcted Wind Load Case Clea r Wind Flow Flow ---_._.
__._..
.
A
7.5 0
13
15° 22.5°
A B A B
f------.o013
30°
A B
37.5°
A
45°
13
CNII'
1.1 0.2 1.1
0.1 1.1 -0. 1 1.3 -0.1 1.3 -0.2 1. 1 -0.3
CNL
eNW
-0.3 -1.2 -0.4
-1.6 -0.9 -1.2 -0.6 -1.2 -0.8 -0.7 -0.2 -0.6 -0.3 -0.5 -0.3
-1.1
0.1 -0.8 0.3 -0.9 0.6 -0.6 0.9 -0.5
eN/. -I
-1.7
-I -1.6 -1.2
-1.7 -0.7 -1.1 -0.6 -0.9 -0.5 -0.7
PITCHED FREE ROOFS 8!5 45°, Y = 0°, 180° No/c'.f:
1.
C'H fllld C"'"L t/('IJ()/C' I/e'l {JH!UIIH'!, (cIJII(ril"'fioll.f from /(If! (lild Imllam sfll/acC'.f) /rw willdw(/rd alld h'(!ward 1111 If of mq{ sUlfaces. r(".~fI(~(· ri ' -1'~1' Clenr II-jllllj/o\\' (Ii.'l1o/c's rl:'faln'('~)' flIl()h.W1ICfc'(/ ."iml jlOII' willi "hkkagl' it'....f dum or equ(ll 10 50% Oh.f/I'U('/l't/ wind JIm" ,',
J
For I'all/('.\" 11/0 bdll'('I'1f 7.Jt> IIml 45 °, fill/~tlr ;1//1''1)o/l1liol/ ;.f pcrmiffl·d. For ndues of 0 les.f ,hUll 7,.s", lise mmmslfJpl' r,;.,.
I.
o"jet'ls heloll' roo/inhlbifing wi"d flow (;, 51Y',1, blockage). l"OC'{liC;f'IILf.
4.
5, (j,
PIf;s (llId JII i/llls sigllx !.igll!ly pr(',~,ql1"l'~ tlc ling IQII'(ll'ds nllcl (lway/rollllhe fOp ru0.f.mr!il('(', AII/llod I '(m'.~ s/'m..,1 for cal'll m~fllng/(' ,~/UlII hI' illllf.'slignlcd,
/'(,,\'Pl!('fil'(!~I"
N"fllfioll.c
I . ." l/orj:;()I/fa{ dill/I'IIS;OIH o{l'tllIl 1I/('f1.mrnl i ll III(' a/olll! wil/d din'clio l/, II "" Me(ln nm{ heigili. III ' .
III
;' :'0 /)in'{'/ioll o{ll·il/(l. de}!I'('(',\'
(} "
AII,~/I' ofpiml(' lI{n)t!(/i 'om
1101'1::0111(11, t!cgl'l'I'.\
Figure 207-1813 Net Pressure Coc f'ficicllts. C,., on Pitched force
Roofs e:5 45°, )' = 0°, 180° of Open Buildings wi th J lei ght h to Length L ratio , 0.25 :5 hlL:5 1.0
Main Wind-Force Resisting System Association 01 Stru ctLlral Engineers of the Pllilippines
.".
CHAPTER 2 - Minimum Design Loads
Wind Direction
=>
1=0'
" Roo r Angle, 0
Load Case A
7.5 0 --_.._.
B A
15°
13 A
22.5°
13 A
30°
B A
37.5°
B A
45°
~
..
-.---..-.
_
B
_____
.~
Wind Directi on y - 0°, 180° Obstructed Wind Clear Wind Flow Flow C NII' CNI• CNIf' eN/. -0.5 - 1.1 0.3 -1.6 -0. 2 -0.9 -0. 8 1.2 -0. 5 - 1.1 - 1.2 OA -0.8 0. 1 1.1 -0.6 -0.6 -1.2 - 1.1 -0. 1 -0.1 -0.8 -0.8 0.8 -1 .3 -I A -0.4 -0.3 -0.5 -0. 1 -0.2 0.9 -0.3 -1.3 -0.6 - IA -OA -0.3 0.2 0.6 -1.2 -0. 3 - 1. 1 -0. 9 -OJ -0.4 .. 0.3 .. _.0.5 _ ~ ~L_
TRO UGHED FREE HOOFS 6:S 45°, Y = 0°, 180°
I.
C"fr (ll/d
CA1.
dCllofC' lief pr('SJIII'("S (colllriblllioll.{ from lOp tlIUI IJO/(om .nll!u('e.f)Ior wil/dward all d leell'tJnl halfof rc1()f.5/lrfilCC.~.
re.fJ)(!C:lil'(!~;"
!. ). " 5.
fi.
C/(>nr wmff flow d ellOU',l' relo(/I'('(v 1fl1O/J.<;iI1lC/ed ",indflow wilh blockage less thatl or eql/a/lo 50% ObslIll(:lc:d 1I'illd/lo11' dC1ltJ/t's obJect.r be/ow roof ;uhibitillg w /1Id flow (> 50% blockage). For \'(I/II("J l~rO belln'c'/I 7.5 0 (111(/ 45°, linea/' jl/((,I'flo(ution is ,wrmiued. For I'(lhu'.t 010 less th(lll 7.5°, N.H! mOllosfop<, r()(~rlotld (·oefJichmu. I'{ux ll lld lIIillll.\· .1'iW IS siJ: I1 (l.i' p n!.\'.mr('s (le/ illg lowards mId away/ro ll1 l he lOp m o.r.~ 1IJf(j(;l', re.ljJ('clil,eI)'. All food (' (I.''' '.\' show/1 fhr ('(I e), /'01?f angle .\'II(lfI he if/I'C',\·ligal('d. NOla/jOlIS: I, ~: 110l'i1.IIIIIIII dill"'llsiolls I!f I m~t: fI1 ('(I.I'II/'et/ ill ,hl' a/o il!!, wind din'('(ioll. //I 11'-- M('wl /'(I(~r"dgh f. m ;' ". /)iq 'ClffllI (~rll'illd. (/t'gr(,l'I; fJ Alm~It'llfJlI(JII(, ofmo/fi'of1l Iwrizol/(rll, df'grC'C'.\·
Figure 207 - 18C Ne t Pressure Coefficien ts , C.. 0 11 Troughcd f ree Roofs 8 $: 45°, Y= 0°, 180° of Open Bui ldings wit h Height h to Length L rati o, 0.25 S hll. " 1.0
Main Wind Force Resisting System 01
National Stru clural Code of the Pllilippin es 6 Edition Volume 1
2·63
2-64
CHAPTEF< 2 ... Minimurn Design Loads
h
Monoslope
e
l}
Distance
Distance
Distance
from Windward Edge
from Windward Edge
from Windward Edga
l}
Wind Direction y=90·
.-..
Roof Angle
Clear Wind Flow -------_._-_._-
Load Case
()
l}
Wind Direction y=90·
Horizontal
D istance [rOll1 Windward Edge
e
Wind Direction y=90· Obstructed Wind Flow
eN
eN
-0.8
-1.2
.•-
- ~ .- - -
All Shapes
A
:;'11
Os; 45 0 B 0.8 . _ - - - -------_.- -------_. - - - - - - - - - All Shapes > IT,::; 211
A ---.-----
-0.6
B
0.5
0::; 45° ._---_.-
-.-------.-~
..
.~.-
All Shapes
-0.9
---
..- ....
-
-
0.5 ----
. .... ...-•.. ~
~
A
-0.3
-0.6
B
0.3
0.3
~
._.•....-
f--
> 2h
OS; 45° ~---.-
0.5
..--
TROUGHED FREE ROOFS a s 45°, y = 0°,180° No(es: I. 2.
3. 5
(,
C\'(/(,110((,.\' /Jd pressures (coli/rih/{{ioll.~.(i·om (OP (lild ho/lolII sill/aces) Clear wil1d .flow denotes 1'('/llIil't:/y IIl1ohslruc/ed wind .flOIl' with h/ockage h'.I".\· Ihml or equal 10 50% ()hS/l"llc/ed wind .I/O1\" d('noles ol~i('Cf.r he/ow /"()(?j"inhihi{illg lI'indflol!' (> 50% l>/or/.:age) 1'1/(.1' and minlls .\"igll.\· sigIJ!/)' pre.Hl/reS (lClillg IOlVords alld aW(Jy(i"o/IJ Ihe fOp roOj"SWjllt:£" /"e.I"/lCClil'e/y All load C(JS(!.I' S!to\\'II'/()/' ('ach l'Oo((lngl(' sh(lll be inFestig(l/ed For mOllos/ope mol;" wilh (hela less l!tall 5 degn'('s. ex l'olIiCS shown applr 01.1'0 for C(1ses lI'iJ('I"(' gOl/Jmo () degr(,es (/I/d O,tJ5 1r'.1"S liJ(l1l or <'<{UII! fo hll,less Ihan or ('qllal 0.25. ,)'('(' Figure 207·IRA/or olher hlL values. Nola/iolls:
I. It
HoriZOI1{ol dimellsioll.\" a/roof," lI1easl(lwl ill fhl' a/ollg \\"il1d direclioll. Mean I"()(?//wiglil. 11/ )' ~, Direcfioll of wind. dcgrccs () ' '" Angle a.lplo!l(, ofro(dfrom horizon/al. degree,r
III
eN
Figure 207-18D Net Pressure Coefficients, on Troughed Free Roofs 8:5 45', )' ~ 0°, 180 0 of Open Buildings wilh Height h to Length L ratio, 0.25 :5 hlL:5 1.0 Main Wind-Force Resisting System Associat"ion of Structural Engineers of the Philippines
CHAPTER 2 _. Minimum Des ign Loads
a
2-65
L
3 2
1 2
3 '-_._ - - - - -
-jalal--
l
e
h
-.----~--.-.---I-.
Roof Angle
eN
Effcctivc
Wind
Clear Wind flow Area 0 Zone 2 Zone I Zone _ .2.""C 3 < a' 2.4 · 3.3 1.8 ·1.7 - 1.1 1.2 I 0' >0\ < 40 2 1.8 -1.7 -1.7 1.2 - -1.1 0.8 1.8 > 4a"2 1.2 -1.1 1.2 - 1.1 1.2 - 1.1 0.5 < {[2 3.2 -4 .2 2.4 -2.1 1.6 - 1.4 1.6 >n2, < 4a 2 7.5" 2.4 -2.1 2.4 -2.1 -1.4 1.2 1.6 > 4a 2 1.6 -1.4 1.6 - 1.4 -1.4 0.8 1.6 < a' : 1.9 3.6 -3 .8 2.7 -2 .9 1.8 2.4 15° . >a~ . .~~_cC._ 2.7 -2.9 _..._--2.7 1. 8 - 1.9 1. 8 > 4a'.. •.. - iT ~ 1.8 1.8 .. -1.9._1.2 -_._- ----_ -------< oJ 5.2 -5 3.9 -3. 8 2.6 3.2 ·2 .5 30° > 0 2, < 4a 2 3.9 ·3.8 3.9 -3.8 2.6 -2.5 2.4 > 4a 1 2.6 -2.5 ·2.5 2.6 2.6 -2.5 1.6 < (J l 5.2 -4 .6 3.9 -3.5 2.6 -2 .3 4.2 >a~, < 4(1' 45° 3.9 -3.5 3.9 -3.5 2.6 -2.3 3.2 > 4(12 2.6 -2.3 2.6 -2.3 2.6 -2.3 2.1
-..2'L.
_
__
-:..l4-
Obstructed Wind Flow Zone 1 Zone 2 - 1.8 0.5 - 1.2 0.8 -3.6 - 1.2 0.8 -1.8 0.5 - 1.8 -1.2 - 1.2 0.5 -1.2 0.5 1.2 0.8 -1.7 -5.1 -2.6 -1.7 1.2 -2.6 0.8 -2.6 -I. 7 - 1.7 0.8 0.8 -1.7 -2. 1 1.8 -3 .2 1.2 -4.2 -3.2 1.2 -2 .1 1.8 -3.2 ----2.1 1.2 -2.1 1.2 -2.1 -2.3 -3.5 1.6 2.4 -4.6 -2. 3 -3.5 2.4 -3 .5 1.6 -2.3 -2.3 1.6 -2.3 1.6 - 1.9 2 .1 3.2 -2.9 -3.8 -1.9 2.1 -2.9 3.2 -2.9 2.1 -1.9 -1.9 -1.9 2. 1
3
N o les:
C~.:d(,,/OW lief pn'.uUn!.f (("(}II/l"iblltioIlJlrolll top amI )w/lom slUfi" :(~~) rdllliwly wlOh\,tnw(,·d willd IIt)w with h/oe/mgt' le.u· l/'lI II (II' equlIl to 50%. Oll'\"{n/( ·t{~d
I. 1.
('({'lIr wind fllll\' d('lIo/ex
J.
roof il/hihitill~ willtll/nw (> 50% hlockfIMe). Fl)r I'(dllC!.~ ,?fO 111111.'1" Ih(ln tho.'w.\"hoWII, lill('ar jllff!'1wfaliOlI
1.
.~ . fI,
!Vimll'o1\' dl.!t",IC'.'i objet:ls
IS pf'rmiltc'd
-'''if,lIi(y pn·...... IlI"('.~ tlClillf, low(ll"(lt (lml away from till' fop nmf'~ '''..'(I(."('. r('.'\II(·("(iI'(·~I·. CompO/WI/IS /11/(/ daddiltJ! c'/ellle-1I1s shnlJ he ,Ic~\·i.f!,m·d/m· positive' nlld lIeRlIlil't' ""f!,~SI'rt' ("oe.Uici('lll.\" showl/, PIlL.. flml
lIIillll." ...iKIlS
Nora/il)/l,I': (/ '"" jO ';-'r; (!( I"{/'\'I hOl'i:nlllfil rlill /Clfs irllls "
Ill'
0..111, whid,,·w·1' i.l· smaller hill
/lO( (e,I',I'
Ihrlll 4% (l(er/sf hm'/zoll/al diIlH'"Siofls or
,\fe{/II I'of!(h cighf, III
'11111';;;1111/(/1 dimell ,l'jOiI O{hllildillg IIIctl,wreri ill '/llolI).! wind din ·' nioll. f) ,~ AII}!./l' (lli i/mll' flf /'Imf limll horiUIllff/I. (h'.~n·l"~
III
r igurc 207 - 19A Net Pressure Coefficients.
Rools
eN 011 Monoslopc Free
e" 45° ofOpcn i3uildings wi th Height" to Length L ratio, 0.25 "hlL:5 1.0 Components an d Cladding 111
Nationa l Structural Code of the Philippines 6 Edition Volume
,1
n,9 ",
hdl.1w
2-66
CHAPTER 2· Minimum Design Loads
, ......... L ··········
L
L " .. ...... ······1
1
3 2
2 1
--1
2
1 2 3
0<10'
Roof An g le
0
eN
Effective Wind Area
< a'
>a 2 , < 4a 2 > 4a 2
O·
< a' , < 4a > 40 2
7.5°
>a
15°
>0 2,
30°
>a 2 , <
2
2
< a' < 4a 2 > 4a2 < a' 4(12
> 4a 1
< a' >a 2 , < 4a 2 > 4a 2
45°
Zone 3 2.4 -3.3 -1.7 1.8 - 1.1 1.2 2.2 -4 .2 -2. 1 1.7 -1.4 l.l 2.2 -3. 8 J.7 2.9 - 1.9 1. 1 2.6 -5 2.0 -3.8 1.3 -2.5 2.2 -4.6 1.7 -3.5 1.1 -2.3
C lear Wind Flow Zo ne 2 - 1.7 1. 8 1.8 -1.7 1.2 ·1. 1 2.4 -2. 1 2.4 -2. 1 1.6 - I. .4 2.7 ·2 .9 -2 .7 ·2.9 -1.9 1.8 3.9 -3.8 3.9 ·3.8 2.6 -2.5 3.9 ·3.5 3.9 -3.5 2.6 -2.3
Obstnlcted Wind Flow Zone 2 Zone I Zon e 3 -1.2 I 0.8 - 1.8 0.5 -3. 6 0.5 0.8 0.8 - 1.8 - 1.2 · 1.8 0.5 -1.2 0.5 - 1.2 0.5 -2. 6 0.8 -1.7 1.6 ·5 .1 1.2 -1.7 0.8 1.2 -2.6 1.2 -2.6 .1.7 0.8 -1.7 0 .8 0.8 - 1. 7 -3 .2 1.2 -2. 1 2.4 -4 .2 1.8 -3.2 1.2 -2. 1 1. 8 -3.2 1. 8 -2. 1 1.2 -2 .1 1.2 -2.1 1.2 -2.3 3.2 2.4 -3 .5 1.6 ·4.6 1.6 2.4 ·3 .5 2.4 -3 .5 1.6 -2.3 1.6 -2.3 1.6 -2.3 - 1.9 -2.9 2.1 4 .2 -3.8 3.2 - 1.9 -2.9 2.1 3.2 -2.9 3.2 2.1 · 1.9 2. 1 -1.9 2.1 · 1.9
Zone I . I. I 1.2 --1. 1 1.2 - 1.1 1.2 1.6 -1.4 - 1.4 1.6 - 1.4 1.6 - 1.9 1.8 1.8 ·1.9 ' 1.8 · 1. 9 -2.5 2.6 -2.5 2.6 2.6 -2.5 2.6 -2.3 2.6 -2.3 2.6 -2.3
--
.:-#-
..:g..
Nul!',\':
I. 2. J "
5. fi
C" d{'I/OtI! 11('1 /J /"('s.fllres (colllnblttioJlsjrom I(}P mId h()tt.:lIIr .wrfilce.\) Ch'a,. wilUljloh' di'1I0(e.f /'ela tj\'f!~V lI/wiJSirllCl('d windj1t1 w lI'illl blockage /c,ts thall or c'l/flul to 51Y'/", Oh.I'I/1/Ctt·d mol inhibiting 11-;l/d flow (> 50% h!ocllllgf.') For w,fuf!$ % otlier thall rhose shown, Ii/wlll' iIlWrpo/a/ioll is flmm ilted. PillS a lld millu.{ .figlls s;gll~{j' pre fsllr(!S n c(mg towards alltl nll'(J.I'/rom tlu' top rooJslltfa ce. n·slu.·Cl il'(,~I"
\I
;11(1 Jlo", (/('110 1<'.$ obj(!(:ts
Compollellts (/1/(1 daddillg C'/('lIl{'lIts shall be' desigl l('d/uI' pO,fitll'l.' lIlItl /Ij'gcllll'(! pre.'i.mre COt~tJidt!IIlJ ,f/wl1'fI . Notaliml,( ' f/ a
II
If)'):' oj It'ItSlllI1ri1 Imla/ riiIJ/f'II,fjrms 01' 0 .411. h'IIkht·"C'I' is
17 M "IIII
I'f1Q/hcigl:r.
/, ~ 110";:011/01 dillJel/siull (~rlmitdi"g m('II.'iI/I'(,t! (I '"
.Hrwl/(,I'
bltl I/(JIIt·s.'i 111(111 J ~"'; oflC(UI liol'j:'olllrll ,/iml'fu jll/lf 01' n.9 til
III
IIII};II' of/Jlml(' o/ruofli'ml/
!/fJ/,;;;:rJIIlfl/,
1/1
a loll,!!. wi/ld (Jill,{·t;OIl . III
deg/'('c·.\·
Figure 207-1 9 B Ne t Pressure Coe ni cients,
Roofs
eNon Tro ilghed Free
e,; 45 ° (l fOr cn Bu ildin gs with I'lei ght" to Length L rati o, 0.25 S hi!.'; 1.0 Component s nnd C ladding Association of Structu ral Engineers of the Philippin es
hdo\\'
CHAf' TER 2 - Minimum Design Loads
L
L
2-67
L
DF
l_--_--_---_ L_--:-~-=---0<10'
O;e: 10'
!
!\
I
Roof Angle
0
- ---0°
7.5 0
15°
30°
45°
eN
Effccl ive W ind Area - ---,.-< a' > (1 2, < 4(/2 > 40 2 < a1 2 >a , < 4a 1
Zone 3 2.4 - -3 .3 1.8 - 1.7 L2 - I. I 2.4 -3.3 1.8 -1.7 > 40 2 1.2 -1. 1 < a' 2.2 -2.2 2 < 4(1 2 1. 7 .... - 1.7 .--- >a>, 4(12 ...l:.L - I . 1 -2.6 --~>1I J., < 4a? 1.4 -2 > 40 2 - 1.3 0.9 < (11 -2 .2 1.6 2 > 0 , < 4a 2 1.2 - 1.7 > 4a 2 0.8 -1.1
--'-4-
Clea r Wind Flow Zo ne 2 1.8 - 1.7 ---_. - 1.7 1.8 1. 2 - 1.1 1.8 -1.7 1. 8 -1.7 1.2 -1.1 1.7 - 1.7 l~ -I 7 I I -I I 1.4 -2 1.4 -2 1.9 -1.3 1.2 - 1.7 1.2 -1.7 1.8 -1. 1
Zone 1. 2 J.2 1.2 1.2 1.2 1.2 1. 1 1. 1
--',,:l0.9 0.9 0.9 0.8 0.8 0.8
Obstru cted Wind Flow Zone! Zone 2 Zone 3 - 1.2 -1.8 0.5 -3.6 0.8 I - 1.2 -1.8 0.5 - 1.8 0.8 .0.8 -1. 2 0.5 - 1.2 0.5 - 1.2 0.5 -1.6 -4.8 -2.4 0.5 I 0.8 -2.4 0.5 -1.6 0.8 -2.4 0.8 0_5 O.S -1.6 - 1.6 -1.6 0.5 - 1.2 0.5 - 1.8 I -2.4 0.8 -1.2 0.8 -1.8 0.5 0.8 - 1.8 ---_. 0.5 -1 .2 0.5 - 1.2 -1.2 0.5 1 0.5 -2. I -2.8 0.8 - I.~-1-~1- . - 1.4 0.5 -2.1 -1.3 0.8 -2. 1 0.8 0.5 - I .4 - 1.4 -1.3 0.5 -1.4 0.5 -1.2 -1.8 0. 5 - 1.1 I -2.4 0.8 - 1.2 - 1.8 0.5 - 1.1 0.8 -1 .8 0.8 - 1.2 0.5 - 1.2 - 1.1 0.5 - 1.2 0.5 I - I. I - 1.1 -1.1 -1.1 -1.1 - 1.1 - I. I -1.1 - 1.1
NOles : I.
eN tinfOIl' 111'1 pn's.wrl'S ("ollfri /)/ffilUl .,-/nll1/ lOp (111(/ iWl/om ,n uf(u:('.'i)
1
Clem' lI'imlJlm,' t/l' IW(t'S n'llIfil 'l'~)' /limbs/melt'" willi/ jim ." with h/tlci;ag(> k~.\· I"f1Il ,II' ,'q ual II} 50%. Ob.~fnl( ·1I!11 lI"illd lloll"d('l/ ofes objt'cls mof il/!tihi/Jlll: \I'illdjl()\\' ( > 5fJ% hfo('/'(IJ:('j. For l'
J. '1 5.
fi .
Na/afiolls : (} 10% 1!(lnl.l'1 /tor iWIII,,1 "illll'll sioll.\' or (J Ail, u,h icht'\'('r ix SlI1ol/(,1' hut 1/01 /t'.I',\' I/'all 4'!'~ o(ll!(/ ,I'I horizonfa l dimemiol1.\' or /'.1('(1/1 m{}rtll' lj~h l , //I
"
I.
eo'
(J '"""~
/(Ol'/zoll /al dillH'II.I' itl l/ ofhlliltiillJ:,
lII('tl.~IfIl'(/ 11/ (/I()II.~
\\'im/ dir('('litm.
11/
AI/KI t' ,!fplwl(' t!frm!l.Ii'lltll !wl'i::oll lai. d(Xrccx
Ro{) f:~
Figu re 207- 19C NC I Pressure Coefficients, e,v 0 11 Troughed Free 8:5 45° o f Open Buildi ngs with Il e igh! " to Length L rati o, 0,25 S hlL S 1.0 Compon ent s and Cladding Nat io nal Stru ctural Code of 1110 Philippin es 6
111
Editi on Vo lume 1
n.9 m
hdoll'
7.·68
CHM') TEH 2 - Minimum Design Loads
, I --p-j-'"
~ ..."" .!:'.... _--- -j
<~~~~~~~~~~~=~~]_;:1
CASE A
I ,
WIND
./ i F\·--II.. _ ...
GROUND SURFAce
ELEVATION
;j J~H~'
view
WIND RA,NGE
;;:'-"'1]-"'.1"'" ,....'j ":lJ r
r_ -:::.:·_=======--==.:::::=:.:.:=-....::_ __
-
~
tU N
CASEB
,
'---1
~
1
GROUND SURFACE
.-..\ -
(UN --.
._-_......_-----_.-
-
...-..!ti.CASE A &
CASE B Aspect Ratio, Bls 1 2 4 1.45 lAO 1.35 1.4 5 l.S5 1.50 1. 65 1.60 1.60 1.75 1. 70 1.70 1.80 1. 80 1.80 1. 80 1.80 1.80 1. 80 1.80 1.8 5 C r, CASE
Clearance < 0.05 1.80 1.85 1.90 1.95 1.95 1.95 1.95
WIND RANGE
. Ratio, "II! 1 0.9 0.7 0.5 0.3 0.2 < 0. 16
; "-
•
CROSS-SECTION VIEW
0. 1 1.70 1.75 1. 85 1.85 1.90 1.90 1.90
0.2 1.65 1.70 175 1.80 1.85 1.85 1.85
0.5 1. 55 1.60 1.70 1.75 1.80 1.80 1.85
5 1.35
<:
.Regi on
-----10 1.30
lA S
lAO
1. 55 1.70 1.80 1.80 1. 85 .._._
1. 55 1.70 1.80 1. 85 1.85
- --_.__.. Re gion
Aspect Ratio, /31" 2 2.25 1. 50
o tos s to 2s 2s to 3s 3s to lOs
4 2.90 1.90 1.30 1.1 0
3 2.60 1. 70 1. 15
6
5 3. 10' 2.00
7 3.40' 2.25 1. 65 1.05
330· 2. 15 1.55 I .Q5
1A5 1.05
8 3.55 ' 2.30 1.70 1.05
9 3.65' 2.3 5 1.75 1.00
10 3.75* 2.4 5 1.85 0.95
r2~.2="lJr .:~~;~~~- "~T l:;c~~;~~;'~~ I ~ ~I- .. -I oom« I,,.....,., - .-- -
"I
----
-
....- -
>~ --
•. _--
..-
. ~ ~...:-=--=.
/
20 1.30 1.40 1.55 1.70 1.85 1.90 1.90
"'8 -...
'
-~- -
-- - - _ . --- - -
o tos s to 2s
2s to 3" 3s to 4.> 4s to 5s
40 1.30
30 1.30 1.40 1.55 1.70 1.85 1.90 1.90
l AO 1.55 1.75 1.85 1.95 1.95
.."_._-_._-"-_...-."Aspect Ratio.
Bls 13 4.00' 2.60 2.00 1.50 1.35
> 45 4.30' 2.55 1.95 1. 85 1.85
1.10 0.90 5.1' to l Os ._. _._ -_.•. ..• . ..........0.55 > lOs - -- -- .Yc.5L
__
------
Nll/e.~ :
I. !.
The ferm "signs" ill "Olt'.<; hi'/OW (lIsa 0l1lllie.f tn ':rreeSfatuJilig wall.f ", Sigll.t I>'if" opef/ing.t comprising I('ss ,hem 30% of 'he gross arM Or"(' da.'f.~ifit'J (IS .{(,Iitl .~i1!'u. f~,.cc ("(WOh."'lIt.( (nl" .foNd ,fi/!lu' "'itll
.l.
/n hr! IIIt,lHfJlied IIJ' {II!' redllctinn /actnr ( 1_ (I_c) 1') . Tn all",1' holh 1I01"IImi uml ohli'l"(' willd dirj'f'limlS. t/Jrlllllnwillg CI'l'.t('f :'ilia/( be nlll.mit'I·r>tI
Opt'lIjllg.t .~hall
he' IJ"!"II/ it/t'd
For slil .:: I: CASE A: }"nu/ll'lII lj,,"':!' ucts Iwrll/lIl /(I flu.'jil(."t, a/IIU' sigll fhrough III(' g c'ofl!f'/ric n'II/I'r. CASE r!'sufl(IIII .fill"(·C' (/(·I.t Iwrmol to fil!' flu'r> q(f/W .fi}!11 (I I U (/i.fWIICC'/I"O/ll rI,(, ,f.:1'Imll'tric <'ell/t'r IIIWI/I"d IIIl' 11"111(/"'((1'/1 ".!Kf· <'f/lml to n.] (imc'.f Ilu' m'('I"u8c' width 0/ tlu' sigll. 1'-,,,. /J/J? 2, CASE C 11111.1' ( rll.f(J /)f' ("I) /I,1";(/"I"('d: (""ISI;' n'.I'It!III/lI .ri)l"n'.~ a('ll1ol"lI/(// 1/) {/II'/U ("l' of file si),!11 Ih ro ug h Ihl' gCOIII <' f";(" ('('Ilfers IIleach I"t'gi(ll/, Fo/" sl/J <. I : .
n:
c:
TIl(' ,WIII(' ("IISI'S
(/.I'
I/hOl'(' ("XCI'li/lha//11('
l'w·(i("(l I/o("(lIioll.l'
I?/".Ih (' I 'C.W IWIl/ fO/"( 'f' S IIC'I,"III" 11111 dis tall C(' 0/111\'(' I ii, ' g ('/llIwlri, ' ( '1' /1 1, '1"
heil:'" U/f!'" .~il: '!. FOl" CAS/;' C ",he/"(' .tn, > nJ" {tltn' cfJt:lfirit!lIf.f "';',,11 h(' 1III1IIiplh·(III.I' Ih(' I"1'11t'cliflll /(Ir 'lm (I .S (l1"('/"(/ge
5.
Um'ur illlcq)()/ntioll ;,~ IX'r",iff('I/ filr ,'ulllC'.' · or,rllt, /ll.f (IIu/I.,A of ill'./" 'htlll .f/lOlI'lI. 711(' "R'~ I(}II" ill III" luhh' IIhm't' j.f tllr' /WI"i:" , .lIal tll.'·llIIu','/rm' , wwdwurr! rdgc
6_
Not(l/i,III '
/I ""' Illwi:'fllllal ditll('/I.~irlll 1I(.,·;gll,
Ii = 1f1'i~/1I .1' "
fir fir" .~iKII.
.,·Ib).
1/1
1/1
I'f'I"th'ol {liml'll.nOlI or lilt: "·;j!II . 11/ ,;, J!/"o,f.\:a/"('tI
I: r.:. /(alillll(.lollIl an'a
L, :-. I IIIr"i:milu/ dil/ll'II,fillll {!{ /"('1111'1/ cm·"cr,
11/
Figllre 207·20 Force Coefficients, Cion Solid Freestanding Walls & Solid Signs of all Height s Other Strllctures ... Method 2 Association of
S~ructurClI
Engineers of the Ptlilippu)cs
"'11111/ /1) (J.f}.i
l illl (,,\' IIi ('
CHAI:>TEf~
,.--
Cross-Section
. ___.____...___LYp.<'.gf Surface _. _____ -...
--~
- --
.jguarc (wind norma! to
(1)£>25)
(1)~ >5.3, D in
Ill,
..-.-------
._._----.__ ..!.1...~ ._----- All All 1.0 - .1.0 All Moderatelt Smooth 0.5 Rough (D'ID = 0.02) 0.7 Vert rough (D'lf) -: 0.08L _ _ -_. 0.8
f~lCC)
Square (wind along di~gonal) Hexagonal or Octagonal
Round
2 -. Minimum Design Loads
hID
2··69
._----2 . 0··~
1.4 1.1 J.2 0.6 0.8 1.0
1.5 1.4 0.7 0.9 0.2
0.8
J.2
q, in kPa All
•.
__. __
0.7
._- - - - - -
-
NOles:
I. 2.
3.
711(' d!'sign wind force shall he ("alculated based on the area of/luI structure projected 0/1 a plane I/omw{ /0 Ihe wind directioll. The force slwll be assumed to act parallel 10 fhe wind directioll. Unear illte/po/alion is permilled for hiD values OIher [hall sholl'lI. Nowlion: /lnder f) '" Diameler of circu/or cross-section ond Icast horizolllal dimen~iolls (~rsqu(lre. hexagonal or octagollal cross-sectiolls al elevolion consideration, m; D' '" Depth (~(prol,./(dillg elements sllch (IS ribs alld spoilen'< 111: II '" Heigh( (?is(rucrure. 111: and q; '" Velocity pressure ('valuated at heighr z above ground. kP(I .
Figure
207~2!
Force Coefficients, (; on Chimneys, Tanks,
Rooftop Equipment and Similar Structures of AI! Heights Other Structures · Method 2
th
National Structural Code of the Philippines 6 Edition Volume 1
2·l0
CHAr-'TE!, 2 .. Minimum Design l.oads
~.
Rounded Members
D,Jq; " 2.5 D,Jq; ,; 5.3
Dfq, >2.5 Dfi >5.3
2.0
1.2
0.8
0.1 to 0.29
1.8
1.3
0.9
0.3 to 0.7
1.6
1.5
1.1
{;
flat· Sided Members
<0.1
.-
..
Noles: /. 2. 3.
4.
Signs lI'ilh openings comprising 30% or //lore a/the gross area are ch1.l'sijied {J.\' OpCII signs The calculalion oj the desigll wind forces shafl he based an the area 0/ 0/1 e:tposed members and eiemcl1H projected (0 (he wind directioll. Forces shall be assumed (0 (lct paral/ello the wind direcfioll. 71lc area A/collsisten! with Iheseji.Jrce coe/ficiclI/s is Ihe solid area projected norma! 10 the willd riil"/!Clioll.
Notation: c "0 Ralio o/.wlid area 10 gross area 1J "" Diameter 0/ a typical round member. m (j: '" Velocity pressure evaluated af heighl z aiJol'{! ground. kPa
Figure 207-22 Force Coefficients, Clan Open Signs and Lattice Frameworks of All Heights Other Structures - Method 2
Association of Structural Engineers of Ole Philippines
011
(I
plant' lion:·
CHAI"TEP 2 .. M'nil1llll1ll)""'[J1l Loads
2·11
Tower Cross Section
4.Oc 2 -5.98+4.0
Square
---1----··-··· Triangle ' - - - - - - - _. ...••• -
3.4£2
--4.7c+ 3.4
_ __.••_.•...•.._•...
.. .•....
Notes: I.
2
3.
For all lI'il1d directions considered. Ihe IIrea A, ("ollsi.I'fell/ wilh {he ,I'!'ec!liedj()/"("(' ('ot{{1icicl!l.\' shall be rhe solid area (?(a IOll'er/lxl' projected 011 rhe plane o/r/Jmf{lce/of {he lower segment under cOllsideration The specijied;;,,.ce cm/jieien!,\' are/ill' {OIl'as will! structural allg!e,I' or .I'imilllljll1l-sided members. For lOwers cOlllaining rOllnded mem/)el".\', il is (/('ceptable to mulliply lhe .I'pec(jil'd .FJrei' ('o{~((icicllix h.l' the /iJ/IO\\'illg faclOr when d('fcrmilling wind/orees 011 .mel! 1II('lIIben ' fUll:! + f).57, /)liI I/O!;:' 1.0
4.
IVilld threes shalf be applied in the direcliOlls re:m/tillg in m(/XilllUIII membel" ji)N'('S and reactiolls. For t{)l\'NS with square erO.I·S.I'r!(·tion.I·. wind (orc!!s shall be fIIUlliplied by Ihe j()ffowillg/aclOl" when the wind is direcled along a IOIVC'r di(lgonal
5.
Wind /orce.l· Oil lower appllrtenallces slich (l.\' ladders. conduil.\". lights. ('{('\'IIlO!".\". ('1(" sha/l he coe/ficir!ntsjor Ihe.I'e elements. Nolatioll: ""' Ratio {?j'solid area to gross area O/OIlC lower/ace for (hc segmel1lllndel" comic/emfioll.
I
(;
-I-
0.751:.1)//11101 > 1.2 calclllilled lI.I'illg
Figure 207-23 Force Coefficients, Croll Trussed Towers orAl1 Heights Other Structures .~. Method 2
111
National Structural Code of the Philippines 6 Edition Volume 1
appropriate force
2··'1/.
CHM'lEP 2 .. Mirllfllurn Design l. oa(15
111'J"
120 "
122 "
.~----~-- .--- ." -
124"
126"E
..- -..--~-----~.
·......·1
~
N 20"
• ,;
HI"
HI"
i ZONE II
ZONE I
V • (200kph)
V • (250kph)
14"
12"
10"
v "'
(150kph)
I'J"
.' I
• -
.1
. •...
•
Figure 207-24 Referenced Wind Zone Map oflhe Philippines Association of Structural Engineers of the Philippine s
.• . . • . - •• .•...... . _ • • j
I I
i
CHAPTloH 2 - Minimum Design Loads
'
..
208.1 General
2-73
COMPONENT is a part or clement of an architectural, electrical, mechanical Or structural system. COMPONENT, EQ UIPMENT, is a mechanical or electrical componclll or elemenl that is part of a mechanical and/or electrical system .
208.1.1 Pnrpose The purpose of the earthquake provisions herein is primarily to safeguard against major stmctural f.1ilurcs
and loss of life. nol to limil damage or maintain fun ction.
COMPONENT, FLEXIBLE, is a compa nen., including ils attachments. having a fundamental period greater than 0.06 second.
208.1.2 Minimum Seismic Design
Structures and portions thereof shall, as a minimum, be designed an d constructed to resist th e effects of seismic
gro und motions as provided in this section. 208.1.3 Seismic and Wind Design When the code-prescribed wind design produces greate r effects, the wind design shall govcm, but detailing requirements and limi tations prescribed in thi s sect ion and
referenced sections shall be followed . 208.2 Definitions BASE is the level at which the earthquake motion s are
considered 10 be imparted to the structure or the level at which the structure as a dynam ic vibrator is su pported. BASE SHEAR, V, is the total design lateral force or shear at the base of a structure.
COMPONENT, RIGID, is a compo nent, in cludin g its attachments, having a fundamental period lcss than or eq ual to 0.06 seco nd . CONCENTRICALLY BRACE D FRAME is a braced frame in which the members are subjected primarily to axial forces. DES IGN BASIS GROllND MOTION is that ground motion that has a 10 percent cha nce of being exceeded in 50 years as determined by a si te-specific hazard analysis or may be detemlin cd from a hazard map. A suite of ground motion time hi 5toric5 with dynamic propcr1ies representative of the si te chara cteristics shall be used to represent thi s ground mo ti on. The dynamic effects of the Design Basis Ground Motion ma y be represented by the Design Response Spectrum. See Sec. ion 208.6.2.
BRACE D FRAME is an essentially ve rtical truss sys.em of the concentric or eccentric type that is provided to resist la tera l forces.
DES IGN RESPO NSE SPECTRUM is an elastic response spectnllll for 5 perce nt equ ivalclH viscous damping used to represent the dynamic effects of the Design Basis Ground Motion for th e des ign of structures in acco rdance with Sections 208.5 and 208.6. This response spectrum may be either a site-specifi c spectru m based 0 11 geologic, tectonic, seis mological and soi l charac teristics assoc iated wi th a spccific site or may be a spectrum conslmcted in accordance with the spect ral shape in Figure 208-3 using the si te-specific va lues of Co and C,. and multiplied by the accele ration of gravity, 9.815 m/sec'. See Section 208.6.2.
BUILDING FRAME SYSTEM is an essentially complete space fmme that provides support for gravity loads. Sec Secti o n 208 .4.6.2.
DESIGN SEISMI C FORCE is .he minimum .ota! strength design base shea r, fa ctored and distributed in accordn nce with Section 208.5 .
BEARING WALL SYSTEM is a stmc.u ral sys.em wi thout a comp lete vertical load-carrying :; pacc frame. Sec Section 208.4.6 .1. BOUNDARY ELEM E NT is an elemen t at edges openings or at perimerers of shear wa lls or diaphragms.
or
CANTILEVERED COLlIMN ELEMENT is a column clement in a la te ral-Iorce-res isting system thaI ca nti levers from a fixed base and has minimal moment capacity at the
top. with l'lIcral forces applied essent iall y at the tall. COLLECTOR is a me mber or clement provided to tra nsfer latera l forces from a portion of a stmcllIre 10 vertica l c lements o r lhe latcnll-forcc-rcsisting system. 111
National Structural Code of the Pililippines 6 Edition Volume 1
?. 74
CHI\PTEH :2 .. MlflirnUIl1 De sign l.oads
DIAPI-IIlAGM is a horizon wl or ncarly horizontal system acting to Irnnsmil lateral forces to the verticalresisting clements. The tern) "diaphragm" includes hOI'izont
MOMENT-RESISTING WALL FRAME (Mlt\\T) IS masonry wall frame especially detai led to provide ductile behavior and designed in conformance with Section 708.2.6.
DIAPHRAGM or SHEAR WALL CHORD is the boundary clement of' a diaphragm or shear w<1 11 that is assumed to takc axial stresses analogous to the nanges or a beam.
ORDINARY BRACE D FRAME (O BF) is " steel· bnlccd fralllc designcd in accordance wit h {he provisions of Section 527 or 528 or concrete-braced frame designcd in accordance with Section 421.
DIAPllnAGM STRUT (drag stru t, tic, coliector) is the element of a diaphragm parallel to the applied load that collects and transrers dia phragm shcfIr to the verticalresisting clcments or distributcs loads within the diaphragm. Such members may take axial tension or compression.
FRAME MOMENT-RESISTING ORDINARY (OIHRF) is a momcnt- resisting fi'ame nol meeting special detai ling requi rements fo r ductile behavior.
II
ORTHOGONAL EFFECTS are the earthquake load effects on structural eleme nts common ( 0 the lateralforce~resisting systems along two orthogonal axes.
DRIFT. See "story drift." DUAL SYSTEM is a combinatio n of momcnt-resisting frames and shear walls or braced frames designed in accordance wi th Ihe criteria of Section 208.4.6.4 .
ECCENTRI C ALLY BRACED FRAME (EBF) is a steel-braced frame designed in conformance with Sect ion 528. ELASTIC RESPONSE PARAMETERS arc forces and defonnatiolls determ ined from an clastic dynamic analysis lIsing an unreduced ground motion representation, in accorda nce with Sect ion 208.6 . ESSENTIAL FACILITIES arc those st nlctures that arc necessary for emergency operations subsequent to
OVERSTRENGTH is a characteristic of stl1lctures where the actual strength is larger than the design strength. The degree of ove rstrength is materia l-and systc m~d cpen dcllt .
Pil EFFECT is the secondary effec t on shears, axial forces and moments of frame mem bers due to the action of the vertical loads ind uced by hori zontal displacemen t of the stnlCture resulting from various loading. SHEAR WALL is a wall designed to resist latern l forces parallel to the plane of the wall (sometimes referred to as vertical diaphragm or stlllctural wa!!). SHEAR WALL-FRAME INTERA CTIV E SYSTEM lIses combinations of shear walls and fmmcs designed to resist latera) forces in propol1ion (0 the ir relative rigidi ties, cons idering interaction between shear wa lls and frames on alI levels. SOFT STORY is olle ill which th e lateral stiffness is less than 70 percent of the stiffness of the story above. Sec Tobie 208-9.
Scction 412 .
SPACE FRAME is a three-dim ensional struct\ !ral system, wi th out bearing walls ) composed of mCIri!)(".iS inte rconnected so as to function :'IS a complete sclfcontained unit with or \vithollt the
LATICRAL·FORCE- RESISTING SYSTEM is that part of th e structural system desi gned to res ist th e Design Se ismic Fon.;cs.
SPECIAL C ONClcNTHICALLY BRACED FRAME (SeBF) is a .s lccl~braccd frame desi gned in conformance.: with the provisions of Section 526.
MOMENT- IU:S ISTI , G F I(AMI-: is " [',\l11C in which members and joints Me cap.lblc or resis ting forccs prinwri ly by Oexure.
S PECIAL MOMENT-RESISTING FRAME (SMRF) is a morncnl-resisting frame speciall y detailed 10 provide
INTERMEOIATE MOMENT RESISTING FRAME (Ii\1RF) is a concrete rrame designed in accordance wilh
I\ssOClatlOI) of Structural En91tlCerS
or th.n Phl liPPUW5
CHAPTEF :2 .," Ivlinirnum Desi9n LOCld~;
ductile behavior and comply with the requirements given Chapter 4 or 5,
jn
SPECIAL TRUSS MOMENT FRAME (STMF) is a moment-resisting frame specially detailed to provide ductile behavior and comply with the provisions of Section 525 . STORY is the space between levels, Story x is the story below icvel x. STORY DRIFT is the lateral displacement of one level relative to the level above or below. STORY DRIFT RATIO is the story drift divided by the story height. STORY SHEAR, V" is the summation of design lateral forces above the story under consideration. STRENGTH is the capacity of an clement or a mcmber to rcsist factored load as specified in Chapters 2, 3,4, 5 and 7. STRUCTURE is an asscmblagc of framing members designed to support gravity loads and resist lateral forces. Structures may be categorized as building structurcs or nonbuilding structures. SUBDIAPHRAGM is a portion of a diaphragm used to transfer wall anchorage forces to diaphragm cross tics.
C C[
)··l~)
seismic coef'flciellt, as set forth in Table 208-7 numerical coemclent given in Section 208.5.2.2 C,. ~ seismic coefficient, as set forth in Table 208-8 D dead load on a structural element De = the length of a shear wall in the first stOI), in the direction parallel to the applied forces, m E, E", Em' E,. = earthquake loads set forth in Section 208.5.1, N F I , FII.I;~"" design seismic force applied to Level i, 17 or ,r, respectively, N f'~) "" design seismic force all a part of the structure, N Fpx =-:-: design seismic force on a diaphragm, N F[ = that portion of the base shear, V. considered concentrated at the top of the structure in addition toF,ION f = lateral force at Level i for use in Equation 208- I 0, N g ;;:: acceleration due to gravity;;:: 9.815 m/sec 2 h" h",hl , ~"" height above the base to Level i, 11 or \ respectively, III = importance factor given in Table 208-\ I" = importance factor for llonstructura1 component as given in Table 208-1 L = live load on a structural clement =: level of the structure referred to by the Level i subscript i "i = 111 designates the first level above the base = that level that is uppermost in the main Level n portion of the structure that level that is under design Level x consideration "x I" designates the first level above the base IH maximum momellt magnitude .N" near~SOllrec factor uscd in the determination of' C in SeismiC Zone 4 related to both thc proximity of' the building or structure to known faults with magnitudes as set forth in Tables 208-4 and 20S -() N,. C~ Ilear-sourcc factor Ilsed in the determination of C, . in Seismic Zone 4 related to both the proximity of the building or structure to known faults with magnitudes as set forth in Tables 208-5 and 208-6 PI ;;:: plasticity index of soil determined in accordance with approved national standards R '''' llulllerical coefficient representative or the inherent overstrength and global ductility capacity or lateral-foree-resisting systems, as set {()I'th in Table 208-11 or 208-13 ,. ;-,. a ratio used in determining p. Sec Section 208.5 . 1 S,,,, Sf), Sc, Su, Sb SF soil proflle types as set f()rth in Table 208-2 )' ... clastic fundamental perind of' vibration of' the structure in thc directioll under consideration, sec II the total design lateral force or shear at the base given by Equalions 208-4, 208-.\, 208·6. 208-7 or 208-11, N V,_ '-'" the design story shear in Story x, N =
li
:=:
::'0
000
VERTICAL LOAD-CARRYING FRAME is a spacc fl'amc designed to carry vertical gravity loads. WALL ANCHORAGE SYSTEM is the system of clements anchoring the wa!! to the diaphragm and those clements within the diaphragm required to develop the anchorage forces, including subdiaphragms and continuous tics, as specified in Sections 208.8.2.7 alld 208.8.2.8. \VEAK STORY IS one in which the story strength is less than 80 percent orthe story above, Sec Table 208~9, 208.3 Symhols and Notation
At; A,. A"
A\ (II'
',"C
ground floor area of structure to include area covered by all overhangs and projections, 1112 the combincd effective arca of the shear walls in the Ill'st story of the structure, 111 2 the minimum cross-sectional area in any horizontal planc in thc first story ora shcar wall, m 2 the torsional amplification f~lctor at Level x numerical coefficient specificd in Section 20g.7 and set fc)rth in Table 208-12
":0
II
c.c
;'CO
National Structural Code of the:: Philippines 6
111
Edition Volume 1
2-·lG
w
CHAPTEH 2 .. Minimum DesI9fl l.oads
in Sections 208.5.1.1 and 208.5.2.1, N Wi. IV,\' that portion of W located at or assigned to Level i or x, respectively, N FVp ::~ the weight of an element Of component, N W,n ;.=; the weight of the diaphragm and the clement tributary thereto at Level x, including applicable loads defined 111 Section portions of other 208.5.1.1, N Z •• seismic zone factor as given in Table 208·3 b. M ,-.c: Maximum Inelastic Response Displacemcnt, which is the total drift or total story drift that occurs when the structure is subjected to the Design Basis Ground Motion, inclueling estimated elastic and inelastic contributions to the total deformation defincd in Section 208.5.9.2, 111m As = Design Lcvel Rcsponse Displacement, which is the total drift or tOlal story drift that occurs when the structure is subjected to thc design seismic forccs, "0 the total seismic dead load dcfined
the design approach used in the design of the structure, provided load combinations of Section 203.4 are utilized.
:0:
8
1
=
p
D"
:.~
208.4.2 Occupancy Categories
For puqJOSCS of earthquake-resistant design, each structure shall be placed in one of the occupancy categories listed in Table 103·1. Table 208·1 assigns importance factors, I and 1/1' and strLlctural observation requircrocnts for each category. Table
---
I. II.
208~!
Occupancy Category'
Seismic Importance Factor, J
Seismic Importance 2
Essential Facilities
1.50
1.50
1.25
1.50
3
Hazardous
Facilities
Factor, I"
Occupancy
horizontal displacement at Level i relative to the base due to applied lateral forces, f,' for use in Equation 208-10, mm Redundancy/Reliability Factor given by Equation 208·3 Seismic Force Amplification Factor, which is required to account for structural overstrength and set forth in Table 208·11
Structures 4 IV.
V.
1.00
1.00 ._- .
Standard
Occupancy Structures 4 Miscellaneous structures
J .00
1.00
1.00
1.00
, See Table 103-1/0/' occlipanL)' categol)' listing. TlU' limitatioll of 1,,/or pond COllllectiollS in Sectioll 208.8.2.3 shalf be 1.0 for the entire connector.
208.4 Criteria Selection
J
208.4.1 Basis for Design
Structural Ob.H!IWllion reqllireme!1ls are given in Secrioll /()7.9. For anchorage a/machinery and (~qUlj)/ll('nl reqlliredfor I!fe-s(ljery sy.\·lellls. Ih(' willie (~f I" shall be taken 0.1" 1.5.
208.4.3 Site Geology and Soil Characteristics
Each site shall be assigned a soil profile type based on properly substantiated geotechnical data using the site categorization procedure set forth in Section 208.10 and Table 208·2.
The minillluill design strength shall be based 011 the Design Seismic Forces determined ill accordance with the static lateral force procedure or Section 20B.S, except as modified by Section 20R.6.5.4 208.4.3.1 Soil Profile Type
Where strcngth design is uscd, the load combinations of Section 20.1.:1 shall apply. Where Allowable Stress Design is llsed, the load combinations of' Section 203.4 shall apply. Allowable Stress Design may be uscd to evaluate sliding or overturning at the soil-structure interrace regardless of
.
III. Special
1llJl1
The procedures and the limitations for tile design of structures shall be determined considering seismic zoning, site characteristics, occupancy, configuration, structural system and height in accordance with this section. Structures shall be designed with adequate strength to withstand the latera! ciisplacements induced by the Design Basis Ground Motion, considering the inelastic response of the structurc and the inherent redundancy, overstrength and ductility of the lateral force-resisting system.
- Seismic Importance Factors
Soil Profile Types SA, Su. Sc. ·So and S/;, are defined in Table 208·2 and Soil Profile Type SF is defined as ", ., requiring site-specific evaluation as follows: I.
Soils vulnerable to potentia! failure O!: collapse lil" seismic loading, such as liquefiable soils, quick iind
Association of Structural Engineers of the Philippines
CHAP1TR 2 - Minimum Design Loads
hi g hly
2.
senSlllve
clays, and
collapsible
weakly
cemented soils.
208.4.4,1 Seismic Zo ne
Peals and/or highly organic clays , where th e Ihickness o f peal o r highly organic clay exceeds 3.0
The Philippine archipelago is divided in lo lwo seismic zones o nly. Zone 2 covers the provinces of Palawan, Sulu and Tawi-Tawi while the res t of the country is under Zone 4 as shown in Figure 208·1 . Each slnrcture shall be assigned a seismic zone factor Z. in accordance with Table 208· 3.
Ill .
3.
Very high plasticil y cla ys wi th a plasticity inde x, PI > 75, where Ihe depth of clay exceeds 7.5 m.
4.
Very thick soft/medium stiff clays, where the depth o f c lay exceeds 35 m . .
The cril e ria sci fo rlh in Ihe definition fo r So il Profile Ty pe SF requiring site-specific evaluation shall be considered. If th e s ite corresponds to these criteria. the si te shall be classified as Soil Profile Type SF and a sile-specifi c
evaluati on shall be conducted. Table 208 -2 . Soil Profile Types Soi l Prol1lc Nam e I
Soil Profile
Generic Desc riplion
Type
A verage Soil Properties for Top 30 m of Soil Profile Shea r Undrained SPT, N Wave
VCI~ci,~' V, mls
---.- - .--Hard SA 1-.._ .. Rock
> 1500
Rock
760 10 1500
S,]
-
Sll ca r St r'cngth ,
(blowsl 300 nlln)
SI! (kPII)
. _- -' -
Very
Table 208-3 Seismi c Zone Factor Z
~~Z~O~N~E=-__+-__~2~__-+_____4~___ J Z
SII
S,..:I S,..
Suit Pmfile 7)'/X' Sf: alw iJld/i(/e.{ (lilY .w il profile
.I
f} III
\1 '__
,h e'
~
lI'i,"
more 'hall of soft cia)' (leJim'd as a .w i/wilh plas /icily index, PI :- 10, <10 p er('('11I (/lId ,f. < 24 kPa . The Pla.~/ic:i~~' 'lldex, PI, arrd
I/W i.f/lIIl! 1'0111<" 1/,
\·hall b e
11' - . .
d ('l <'r mill('d i ll occOI dfll/ C'1!
with
(lf IPI"lH'l'ti IUI/iwwl ,t l om/nrd.\·.
0.40]
In Seismic Zone 4, each Site shall be assigned near·source factors in accordance wilh Tables 208·4 and 208-5 based on the Seism ic Source Type as set forth in Sectio n 208.4.4.4. The va lue of Nfl used to detcnnine Co need not exceed 1.1 for structures complying wit h all the following condition s: I.
The soil profile Iype is SA . So, Sc or S'l'
2.
P ~ 1.0.
3,
Except in single-story stnlclures, residential building accom modatin g 10 or fewe r perso ns, private ga rages, carports, sheds and agri cu ltural buildings, momclH frame syste ms designa ted as part of the lateral· forceresi sting sys tem shall be special moment-resisting frames ,
4.
The exceptions to Section 5 15.6.5 shall not appl y, except for co lulllns in onc·story build ings o r columns at the lOp story of mullistory bu ildings.
5.
None of the following stru ctural irregula rit ies is presem : Type 1,4 or 5 a fTable 208·9, and Type I or 4 of Table 208· 10.
.
360 to Soi l ad > 50 > 100 760 so n Roc k Sliff Soil 180 10 1.1 III 50 10 Pro Ii iI! 360 50 100 Sofl Soi l < 180 < 15 < 50 Pro fil e Soil Requi ring Site-spec ific Evaluatioll . See Section 208.4 .3. 1
S"
0.20
208.4.4.2 Seismic Zone 4 Near-Source Faclor
Dense
I
2·77
208.4.4.3 Seismic R esponse Coefficients Each structure shall be assigned a seismic coefficienl. en. in accordance with Tab le 208-7 and i1 se ismic coefficient. C,~ in accordance w ith T
208.4.4 Si t e Se ismi c Hazard C hara c t<.'r is lics
Se ismi c ha zard duracteristics for Ihe site shall be eSlahlished based Oil the seismic zOll e lind proximit y of th e S lt ~ to ;u.: tive seismic sources, site soi l pro fil e c haracteristics ilnd the st ructure's importance f' IC{Or.
208.4.4.4 Seismi c SOllrce T ypes Table 208·6 defines the Iypes o r seismic SOllrces. The location and type o f seismi c so urces to be used for design shall be established based 0 11 approved geological data; sec Figure 208-2A. T ypc A sources shall he dete rmined ('rolll Figures 208-2B. C. D. E or the most recent mapp ing of ac ti v~ 1:1UIIS by th e Philippine Inslilu te of Volcano logy and Seismology (PHIVOLCS).
National S tru ctLJ n~ 1 Code of til e Philippines 6
111
Edition Volum e 1
2-78
CHAPTEFo( 2 ··· Muul1lum
Dc:!~ lun
I.o'.lcl!-,
ear-Source Factor N"
Table 208-4
Seismic Source
Table 208-6 - Seismic SOllrce Types'
-
TlP!
S5k lll
2 10k 'll
A B C
12
1.0
1.0
1.0 _I L
- - - - -- ........._ _L<2.. _ ....... __._ 'fab le 208-5 -~
Closest Oi stance To Known Seismic Soul"ce l $ 5 km
10km
A
1.6
1.2
1.0
B
1.2
1.0
1.0
1.0
1.0
1.0
..
-
C
B
.\,Itull
1>1'
tllh'lI
as
that
that
are of large
M ,? 7.0
events have a
...
__._--
6.5 ~ M < 7.0
C.
TIl(' Nl'aT-Sauro.! Foctor m;l)' hI' based 011 tilt' IiI/ifill' illlel]1OluluJII of 1'1IJII('.~ jiJr distal/CeS 0Ii11'1' Iilol/ lhos(- shou'l/ i" til(' lahle . SO/iTCf!
D\ ti lt ;~~t.'ll
1\'1ax i~;;;-~-\1;nl-e;~
hi gh rate of seismic ac ti vity. All faults other (han Types A and
15 km
- . --~
;",'r:
.. M. ~ll.~!! "d.!2...11L. Faults
ma gnitude
Paults that are not capable of producing Jarge magnitude earthquakes and have that a relatively low rate of seis mic activity.
Notes/or Tahle's ]08.4 and 108.j :
The closes! di.HIUIC(' to .'u'ismic
Description
and
Typo
~
Seismic Sour'cc
producing A
"._-
~ ;:i \~·,':c ~;:'"
ca pable
--_.
..........
Source
Seismic Source Type ----
.... _ ..
Ncar-Source FlI<: tor, N,,)
Sr.ismic
..
I
Closest Dista nce To Known Seism ic So ut'ee 2
C
til('
mil/imuflt diJt(lIl(,(' betwe"" til(' sifl~ (llid thl' urca i!l'Jcribl'd lIy tIl(' verticaf projer'lion of {he ,WI/rei! Oil llie ,1'llijiICI' (i.e .. slIIfaC(' projection (~/jillllt p lul/e) . 77w XIII/aCe projectiol/ lI('ed IWt il/{'/lId(' porrioll.~ of ,II, .I'Olln 'l! al dt'pfhs olIO kill or gn'tlla. TIlt' largest value 0/ 'he Nt'(lI'·Sourct' Factor cOJ!sid~'ring I//! source.I' shall IJ(' IIsed/or ",'sigll.
L...,--
SuhduClio/! S()lIr(,(',\' shall be I!m/ll(lled on
M<6.5
f1
site-specijlc basis.
C
Table 208-7 - Seismic CoefGcient,
Seismic Zone Z
So il Profil e
Type
Z
SA
~
Z ~ O.4
0.2
0. 32Na OAONa OAON, OA4N. OA4N. See Footllote I a/Table 208·8 0 . 16 0.20 0.24 0.28 0.34
SI! So
S" S, S,.-
Tab le 208-8 .. Seismic Coefficie nt, Cv Seismic Zone Z
Soil I'rofile Type ..
S" SB Sc ..
51) S,
SF. L._ _
Z" O.2
Z.. O.4
0.16
OJ2N"
0.20 0.32
OAON" 0.56N,,__ _ 0.64N,. - - 0.9611'" - - - -
OAO 0.64
St'C' FOrlilJole I a/ Table 108-8
Sitt"-V)('dlic ~I'(}{('dmin" illl'l':>liglllic)f/ lIlId dYlI(lmic JI/(' j ·CSlJOII.f C' sh(l/J lu" ' <'lji}l m('d to dC/I'I'mill(, .teiJIII;(· C()('j]ir:il'lll.f
IIIUlZI'S/\
Association of Structural
EI19J1H~nrS
of tliB PhilipPlnmj
CHAPTER 2 .. Minimum Design Loads
2-79
208.4.6.3 Moment Resisting Frallle System 208.4.5 Configuration nequirelllents
alln 208.4.5.2.
A structural sysfem with an essenti ally complete space frame providing support for gravity loads. Momentresisting frames provide resistance to lateral load primarily by flexural action of members.
208.4.5.1 Regular Structures
208.4.6.4 Dual Sysl·em
Regular stnlctufcS have no significant physica l discontinuities ill plan or ve rtical configuration or in their
A structural system with the following features:
Each structure shall be designated as being structurally regular or irregular in accordance with Sections 208 .4.5. 1
lateral- lo ree-resisting systems such as features described in Section 208.4.5.2.
the
irregular
An essentially complete space frame that provides supp0l1 for gravity loads.
2.
Resistance to latera l load is provided by shear walls or braced frames and momentwresisting frames
208.4.5.2 Irregular Structures
J.
(SMRF, IMltF, MMRWF Or steel OMRF). The moment-resisting frames sha ll be designed to independenlly resist al leasl 25 percenl of Ihe design
ilTcgular structures have significant physical discontinuities in configuration or in their lateral force-resisting systems. Irregular features include, but
base shear.
are Ilot limited 10. those described in Tables 208-9
alld 208· 10. All slruclu res iu occupancy Calegories 4 and 5 in Seismic Zone 2 Ileed 10 be evaluated only for verlical irregularili« of Type 5 (Table 208·9) and horizonlal irregularilies of Type I (Table 208-10).
2.
Sll1Jcturcs having any of the features listed in Table 208 9 shall be designated as if having a vertical irregularity. v
Exception:
Where I/O stmy drift ratio under design lateral forces is greater thal/ 1.3 times rhe story drift ratio of rhe stDlY above, the SfnJcture may be deemed 10 not have the stroctural irregularities of Type J or 2 in Table 208-9. The story drift ratio for the top two slories need not be considered. The stDlY drifts for this de/ermina/ion may be
,
I.
3.
The Iwo syslems shall be designed 10 resisl Ihe lola l
design base shear in proportion to their relative rigidities considering the interaction of the dual system a l all levels. 208.4.6.5 Cantilevered Column Syslem A structural system relying on cantilevered column elements for lateral resistance. 208.4.6.6 Undefined Structural System A sl ruclural syslem no l lisled in Table 208 ·11 . 208.4.6.7 NonbuiJding Structural System
A struc tural system conforming to Section 208.9.
calcuiated negiecliflg torsional effects. J.
Structures havin g allY of the features listed in Table 208-10 shall be designated as having a plan irregularity.
208.4.7 Height Limits
Height limits Cor the variolls structural systems in Seismic Zone 4 arc given in Table 208·11.
Structural systems shall be classified as one of the types lisled in Table 208-11 and defined in Ihis seclion.
ExcepJion: . Regu!ar slruCllJres may ·exc.~ed· /III~se limits by not more than percent for unoccupied st'1lctures, which we not. .. . accessible to tHe general public.
208.4.6.1 fleadng Wall Sys tem
208.4.8 Selection of Lateral Force Procedure
A structu ra l sys tem without a complete vertica l Joadcarrying space frame. nCilring wall s or bracing systems provide su pport for all or most gr;wily loads. Resistance 10 latera l load is provided by slH!Hr Willis or braced
Ally structure may bel and certain structures defined below shall be, designed usin g th e dynamic lateral -force procedurcs ofScclion 20R.6.
208.4.6 Slnlclu,·.J Systems
so
frames . 208.4.6.2 Bllilding Framo Syst em
A slructural system with (ill cssc!llially complete srmce fnllnc providing SliPPOrl for gravity IOiH.is. ResistClllce to late ral load is provided by shear walls or braced fr:lJnes,
NatiofliJl Struc tural Code of It'll.'! Pililippin es 6
th
Edition Volume 1
?-80
CHAPTEH 2 -- Minimum Design loads
Tablc 208- 10 Horizon[al Structural Irregularities Tab le 208-9 Vertical Stmcturallrregularities Irregularity Ty pe and Definition
J.
2.
Stiffness Irregularity - Soft Story A soft story is one 111 which the Int eral stiffness is less than 70 pcrccnt of th at in thc story above or Icss th an 80 perccn t of the average st iffn ess of the three stories above. Weight (Mass) Irregularit y Mass ilTegularity shall be considered
to exist where the effective mass of any story is more than 150 percent of the effective mass of an adjacen t story. A roof that is lighter than Ih e ncar below need not be considered.
3.
Reference Section
Irregularity T ype and Definition I.
208.4.8.3 Itc1l1 2
208.4 .8.3 item 2
2.
Rc-Entran[ Cor ner Irreg ularity
3.
Plan config urat ions of a stmcture and its latera l-foree-resisting system contain re-C nLT"dnt co rn ers. where both projections o r the stru cture beyond a re-entrant corner arc greater thHn 15 percent of th c pl nn dimensi on of the stmclure in the givcn directi on. Diaphragm Discontinuity
Vertical Geometric Irregularity
4.
horizontal dimension of the latera!-
208 .4 .8.3
Ite lll 2
morc than 130 percent of that in an
Irregulari[y
adj acent story. One-slory penthouses need not be co nsidered. In-Plane Discontinuily III Vertical
disDiaphragms with abrupt continuities or variati ons in stiffness,
Lateral-Force-Resisting ElclHCllt Irregularity
areas greater than 50 percent o f the gross enclosed area of the di aphragm, or changes in effect ive diaphragm stiffness of more than 50 percent from one story 10 the next.
An in-plane offset of the lateral-I oadresisting clements greater th an Ihe
5.
including those having ClI to ut o r open 208.5.8 . 1
length of those clements. Discontinuity In Capacity - \V rak
4.
Sto ry Irreg ularit y A weak story is one in which the
stO ry strcngth is less than 80 perccnt of that in the story above. Thc story strength is the to[al strength of all
seismic-resisting clements sharing the story for the direction under consideration.
208.4 .9. 1
Section
208.8 .2.8
Item 6
,
including accidenta l tors ioll. at one end of the st ructure transverse to an axis is more than 1.2 Limes the average of the story drifts of the two ends of the stnJcture.
Vel1i cal geome tric irregularity shall be co nsidered to exist where thc force-resisting system in any stolY is
Torsional Irregu larit y - To Be Considered \ Vhell Diaphragms Are Not Flexible be Torsional irregularity shall co nsidered to exist when the maximull1 story drift. computed
Rer"'cn cc
5.
208.8.2.8 items G and 7
208.8.2_8 ItemG
Out-Or-Plan e Ofrsets Irreg ularity Discontinuities ill a Illtera l force path, such as out-of-planc of(,cts of Ihe
208.5 .8.1 208.8.2.8
vertica l elements Nonparallcl Systcms Irregu lari ty Thc vertical latcral-Ioau-resisting elcments ,Irc not parallcl to or symmetric about th e major orth ogo nal axes of Ih e lateral force-resisting systems.
515 .7
Association of Stru ctura l £:n9incefs of tile Phllipplll n~,
Item 6;
208.8. 1
---
CHArYlH, 2 ." Minimuill Design Loads
208.4.8.1 Simplified Static
soils at the site and shail conform to Section 208.6.2, Item 4.
The simplified static lateral-force procedure sct forth in Section 208.5.2.3 may be used for the following stnlcllHCS of Occupancy Category IV or V:
208.4.9 System Limitations
1.
208.4.9.1 Discontinuity
Buildings of any occupancy (including single-family dwellings) not more than three stories in height excluding basements that usc light-frame construction.
2.
Other buildings not more than two stories in height
excluding basements.
.
208.4.8.2 Static The static lateral force procedure of Section 208.5 may be
used for the foHowing structures: 1. 2.
3.
Strucfures with a discontinuity in capacity, vertical irregularity Type 5 as defined in Table 208-9, shall not be over two stories or 9 111 in height where the weak story ha;·; a calculated strength of less than 65 percent of the story above.
Exception: . Where the weak story is capable of!i~sisting a total lal(rqi. . seismic' force of n" times.. jlii design fore. .',,<.. , ..• prescribed in Section 208.5.
All stmcl1Jres, regular or irregular in Occupancy Categories IV and V in Seismic Zone 2.
208.4.9.2 Undefined Structural Systems
Regular stilletures under 75 III in height with latera! force resistance provided by systems listed in Table 208-11, except where Section 208.4.8.3, Item 4, applies.
For undefined structural systems not listed in Table 208· II, the coefficient R shail be substantiated by approve' cyclic test data and analyses. The following items shail be addressed when establishing R:
Irregular stnlctures not morc than five stories or 20
I.
Dynamic response characteristics,
2.
Lateral force resistance,
3.
Overstrength and strain hardening or softening,
4.
Strength and stiffness degradation,
S.
Energy dissipation characteristics,
6.
System ductility, and
7.
Redundancy.
III
in height. 4.
2-81
Stmctures having a flexible upper portion supported on a rigid lower portion where both portions of the stnlcture considered separately can be classified as being regular, the average story stiffness of the lower portion is at least 10 times the average story stiffness of the upper portion and the· period of the entire structure is not greater than 1.1 times the period of the upper portion considered as a separate structure fixed at the base.
208.4.8.3 Dyn,"nic The dynamic lateral-force procedure of Section 208.6 shall be used for all other structures, inclu.ding the following: I.
Structures 7S m or more in height, except as permitted by Section 208.4.8.2, Item I.
2.
Structures having a stiffness, weight or geometric vertical irregularity of Type I, 2 or 3, as defined in Table 208-9, or structures having irregular features not described in Table 208-9 or 208-10, except as permitted by Section 208.5.4.1.
3.
Structures ovcr five stories or 20 111 ill height in Seismic Zone 4 not having the same structural system throughout their height except as permitted by Section 208.6.2.
4.
St!1lctures, regular or irregular, located on Soil Profile Type SF, that have a period greater than 0.7 second. The analysis shall include the effects of the
208.4.9.3 Irregular Features All structures having irregular features described in Table 208-9 or 208-10 shall be designed to meet the additional requirements of those sections referenced in the tables.
208.4.10 Alternative Procedures Alternative lateral.,force procedures using rational analyses based on well-established principles of mechanics may be used in lieu of those prescribed in these provisions.
208.4.10.1 Seismic Isolation Seismic isolation, energy dissipation and damping systems may be used in the design of structures when approved by the building official- and when special detailing is used to provide results equivalent to those obtained by the use of cOllventional structural systems.
National Structural Code of the Philippines 6
th
Edition Volume 1
CHAPTE:f~
2··82
2 ... Minil'fH.Hll Design l.oads
208.5 Minimum Design Lateral Forces and Related Effects 208.5.1 Earthquake Requirements
Loads
and
Modeling
208.s.l.l Earthquake Loads StJ1lctures shall be designed for ground motion producing structural response and seismic forces in any horizontal direction. The following earthquake loads shal! be used in the load combinations set forth in Section 203:
=
E",
=
E, .
=
(208·2)
the product of the wall shear multiplied by 31 'wand divided by the total story shear, where I,.. is the length of the wall in meter.
resulting from the combination of the horizontal component, Ell> and the vertical component, E, .. the earthquake load due to the base shear, V, as set forth in Section 208.5.2 or the design lateral force, Fp, as set forth in Section 208.7. the estimated maximum earthquake force that can be developed in the stlUcture as set forth in Section 208.5.1.1, and used in the design of specific elements of the structure, as specifically identilled in this code. the load effect resulting from the vertical component of the earthquake ground motion and is
equal to an addition of o.~/Dto the dead load effect, f), for Strength Design, and may be taken as zero for Allowable Stress Design. .0" = the seismic force amplification factor that is required to account for structural overstrength, as set forth in Section 208.5.3.1. p = Reliability/Redundancy Factor as given by the following equation: (20R·3) where: ("""
.~~
shall be taken as the maximum value or
For shear walls,
= the earthquake load on an element of the structure
E"
For moment frames, ri shall be taken as the maximum of the sLIm of the shears in any two adjacent columns in a moment frame bay divided by the story shear. For columns common to two bays with moment-resisting connections on opposite sides at LeVCI i in the direction under consideration, 70 percent of . the shear in th,1t column may be used in the column shear summation.
(208·1 )
where:
E
For braced frames, the value of ri is equal to the maximum horizontal force component in a single brace element divided by the total story shear.
the maximum clement-story shear ratio . For " given direction of loading, the element-story shear ratio is the ratio of the design story shear in the most heavily loaded singlc clement divided by the total design story shear.
For fIny given Story Level i, the elcl1lent-stolY shear ratio is denoted as r,. The maximulll elemcnt-story shear ratio 1'''''1\ is defined as the largest of the clement story shear ratios, r" which occurs in any of the story levels at or below the two-thirds height level oCthe building.
I"i
For dual systems, ri shall be taken as the maximum valur: of ri as defined above considering a!llateral~load-resisting elements. The lateral loads shal! be distributed to clements based on relative rigidities considering the interaction of the dual system. For dual systems, the value of p need not exceed 80 percent of the value calculated abovc. p shall not be taken less than 1.0 and need not be greater
than 1.5. For special moment-resisting frames, except when used in dual systems, p shaH not exceed 1.25. The Ilumber of bays of special momcnt-resisting frames shall be increased to reducc r, such that p is less than or equal to 1.25. /!.,xception: All may be taken as the average floor area in the upper setback portion 0/ the building where a larger base area exists at the ground floor. When calculating drift, or when the structure is located in SeismiC Zone 2, p shall be taken equal to ! .0.
The ground motion producing lateral responsc and design seismic forces Illay be assumed to act nOll-concurrently in the direction or each principal axis or the structure, except as required by Section 20X.8.1. Seismic de'l(.1 load. /-V, !s the total dead load :lnd applicable portions or other loads listed below. I.
In storage and w,lrehousc occupancies, a minimulll or 25 percent orlhe floor liv(, lo,HI shall be applicable.
2.
Where a partition load is used in (he floor design, load of !lot kss (hall (l.S kNhn~ shall be included.
1.
Total \'.'eight included.
Association of Structural Enqirwers of tile Phi!IPPIrl(?5
or
permancnt equipment shall be
CHAPTER 2 - Minimum Design
20B.5.1.2 Modelling Re(IUircmcnts The mathemat ical model of the ph ysica l slructure shall include all elements of the lateral-force-resisting system. Thc 1110del shall also include Ihe sliffness and slrenglh of elemen ts, whi ch arc gignificanl 10 the distri bution of forces, and shall represent Ihe spatial distrib ution of the mass and stiffness of the structure. In add ition, th e model shall comply wilh the fOllowing: 1.
2.
2-63
The total design bilse shear shall not be less than the
followiug:
V=O.l
r:~JW
(208-6)
In addition, fo r Seismic Zone 4, the total base shear shall also not be less than the following:
v = O.BZN,. 1 W
Stiffness propcl1ics of reinforced concrete an d masonry eleme nts shall cons ider the ciTcels o f cracked sec tions.
For steel moment frame systems, the contr ibution of panel zone deformatio ns to overall story driti sha ll be included.
Loads
(20B-7)
II 20B.5.2.2 Structure Period The va lue of T shall be determined from one of Ihe following melhods:
Method A:
20B.S.1.3 Ph Effects
I.
The resulting member forces and moment s and the story
cor all buildings, Ihe value T may be approximaled from the following equalion:
drifts induced by Ph effects shall be considered in the evaluation of overall Slnlctural frame stability and shall be evaluated using the forces produci ng the disp lacements of tJ-s. P6 need not be considered when the ratio of secondaJY moment to primary moment does not exceed 0.10; the ratio may be evaluated for any stOty as the produci of the tolal dead and Ooor live loads, as required in Section 203, above the stOty times the se ismic drift in that story divided by the product of the seismic shear in that story times th e height o f lhat story. In Seismic Zone 4, P6. need'"not be considered whcn the story drift rati o docs not exceed 0.02 , R. 20B.S.2 Static Force Procedure
(208 -4)
The total design base shcar need not exceed the following:
V = - - - '- W II
31 4
(208-B)
where:
C : : : 0.0853 for steel momen t-resis ting frames. for reinforced concrete momentresisting frames and eccentrically braced frames. C, = 0.0488 fo r all other bu ildings. C,
== 0.0731
Allernativcly, the value of Cr or mClSOt1r)'
rat
structures with concrcte shear walls may be taken as 0.0743 1.fA: .
The val ue of A, shall be determined from Ihe followi ng
208.S.2.1 Dcsignllase Shear The total des ign base shear in a given direction sha ll be determined from the following equati on:
2.5C, 1
T = C/"II)
(20H-S)
N8tioJ'lai Structural Code of the
equa ti on:
(208- 9)
The value of exceed 0.9. 2.
Del hl1used in Equation
(20B-9) shall not
Method Il :
The fundamental period T' may be calculatcd lIsi ng the structu ral properties and deforma tional characteristics of th e res isti ng elemcnts ill a properly su bstantiHted analysis. The
Philj ppl!'l~~S Gi ll Editi on Vo lum e '1
2-84
CHAPTEH 2 - Minimum Oesign Loads
Table 208- 11 A Ear1hquake-Force-Resisting Stmctural Systems of Concrete -~ - -
Basic Seismic-Force Resisting Syst m
R
no
4.5 4.5
2. 8 2.8
NL NL
5.5
2.8
NL
75
5.6
2.2
NL
NP
5.5
2.8
8.5
2.8
NL
NL
5.5
2.8
NL
NP
3.5
2.8
NL
NP
8. 5 6.5
2.8 2.8
NL NP
NL NP
6.5 4.2
2.8 2.8
NL NL
50 50
4.2
2.8
NP
NP
2.0
NL NL
10 50
-4
I', !
A. Bearill/i Wall Systems • Special rein forced concrete shear walls
•
OrdilHuy reinforced conCrete Shf:I '· walls
B. Buildill!: Frame Systems • Special reinforced concrete shear walls or braced frames
•
Ordinary reinforced concrete shear walls or braced frames
•
Intcnncdiatc precast shear walls or braced
• •
Special reinforced concrete moment frames InlCnllCdiate reinforced concrete moment frames
•
Ordinary reinforced concrete moment fra mes
frames C. Aloment-Resistill/( Frame Systems
D. Dual Systems • Special reinforced concrete shear wall s • Ordinary reinforced concrete shear walls E. Dual System with Intermediate Momellt Frames SjJCcial reinforced concrete shear walls • Ordinary reinforced concrete shear walls • Shear wall frame interactive system with ordinary reinforced concrete moment frames and ordinat.I reinforced concrete shear walls F. Cantilevered Column BuildillJ! Systems • Cantilevered column elements G. Shear Il'all- Fram e imeractioll Systems
·
System Limitation and Building Height Limitation by Seismic Zone, m Zone 4 Zone 2
.. 2.2 5.5
2.8
Association of Structural Engineers of the PI)ilippin8s
--
50
NP
CHAPTER 2 - Minimum Design Load s
2-85
Table 208-11B Earthquake··Force· Resisting Structural Systems of Steel System Limitation nd Building Height Li mi' ion by Seismic Zon e 04 Zone 2
R
no
2.8
2.2
NL
4.4
2.2
NL
4.5
2.8
NL
Basic Seismic-Force Resisting System
A. Bearill!! Wall Systems
•
· • •
•
..
Light steel-framed bearing walls with tension only bracing Braced frames where bracing carries gravity load Light framed walls sheathed with wood stntctural panels rated for shear resistance or steel sheets Light-framed wa lls with shear panels of a ll ot her light materia ls Light-framed wall systems using flat strap bracing
._.
' J
-
4.5
2.8
NL
2.8
2.2
NL
8.5
2.8
NL
6.0
2.2
NL
6.0 3.2
2.2 2.2
6.5
2.8
NL
2.5
2.8
NL
7
2.8
NL
8
2.8
NL
7
2.8
NL ·
8.0 4.5 3.5 6.5
3 3 3 3
NL NL NL NL
8
3
NL
5 6
3
NL 48 NP
-
..' 0 '"
...
B. Buildill!! Frame Systems
• • •
• • •
· • •
Steel eccentrically braced frames (EBF), momen t-resis ting connections at co lumns away from links Steel eccentrically braced frames (EBF), non moment-resisting connections at columns away from links Special concentrically braced frames (SCBf') Ordinary concentri cally braced frames (OCSF) Light-framed walls sheathed with wood structuralpanels I sheet steel panels Light fmme wa lls with shear panels of all other materials Buck lin g-restrained braced frames (BRBF), 110 n l1lolnc llt-resisting beam-colu mn connection Buckling-restrai ned braced frames, mOlllcnl resistin.e beam-colunm connections Specia l steel plate shear walls (S PSW)
C. Moment·Resisting Frame Systems
•
• • • • • • •
Special moment- resisting frame (S MRF) Intermediate steel moment frames (1M!') Ordinary moment frames (OMF) Speciallruss moment framcs (STMF) Special com posi te steel and concrete momenl frames In lermediate co mp
D, Dual S,'slems wilh Special t.lomelJl Fram es
• • •
1
..-
-
.-
3 3
)
Steel eccent rically braced frames __ S Spcci,lI stcel concent rica lly braced framcs___ ---- - 7-.Co mposite steel and concrete eccentri ca ll y 8 braced frame - - - -_._.
Nt NL
..
2.8 2.8
NL
_.
2.8 ... - - - - - - - 111
National Structuml Code of !he Philippines 6 Edition Volum e 1
_.. _.
-, ..- .. -
., o . ..
I,
---
.. .
t" .-.
N .•
.. .._-_..N h.:
,
!, ..
:. ' "
NL= i NL
_._-----
"
.__ ." ..
i'<
._ .
-_.
-
2-86
CHAPTEH '2 .- MlIlllllum DesIgn Loads
Table 208-1 1B(eonl'd) Ealihquakc-Force-Resisling Sll1Ielural Syslems of Sleel
~
Basic Seismic-Force Res ist in g System
•
• •
•
·• •
Composite steel and concrete concelltric ally braced fi·am e Composite steel plate shear wa ll s Buck ling-restrained braced fmllle Special Slee l plate shear wa lls Masonry shea r wa ll wit h slee l OMRF Sleel EBF with sleel SMRF Stecl EBF wi lh slee l OMRF
·
Special concentrically braced frames wi th steel
·
Special concentrically braced frames with steel
SM RF
OMRF E. Du al SJ'stem witlt Intermediate IWomelll Frames • Special slccl co ncen lrically braced frame • Composite steel and concrete concentrically braced frame • Ordinary co mposite braced frame • Ordinary composite reinforced co ncrete shear walls with stee l elements I"~ Calltilel'ered Columll Buildill!! Systems • Specia l steel moment frallies • fnterl11cdiatc steel moment frames • Ordinary sleell110ment frames • Cantilevered colu mn elements G. Steel Systems lI ot Specifically Detailed fo r Seism ic R esistance, Excluding Cantilever S},stel1ls
_-
... .. - -.-_ System Li mii i'. ; !: lIi ;1 1l
R
n.
6
2.H
7.5 8 8 4.2 8.5 4.2
2.8 2.8 2.8 2.8 2.8 2.8
7.5
2.8
NL
NL
4.2
2.8
NL
50
.
NL .-
NL NL NL NL NL NL
. -- ...... --
~-
.
-
NL
-NL _ _-_ NL
·····_h .••.•.
...
- - ------.NL -- . .-----.
50 -_. _-----. --
NL 50
-. -
6
2.8
NL
NP
5.5
2.8
NL
NP
3.5
2.8
NL
NP
5
2.8
NL
NP
2.2 1.2 1.0 2.2
2.0 2.0 2.0 2.0
10 10 10
NP NP
NL
10
3
3
NL
NP
10
Table 208- 11C Earthquake-Foree-Resi$till g Structura l Systems or Masonry
Basic Seismic-Force Resisting System
A. Bearing IVal/ S~lste ms • Masonry shear wa lls 11. Buildi,,!: Frame Sl,.w ems • Mason~ shear walls C l'1oment-R esi.*ifiIlK Fram e SJ'stemJ • Masol1JY moment-resist ing w
·
no
R
System Limitation and Building Height Limitation by Seismic Zone 1 m ZOlle 4 ...Zone 2
4.5
2.8
NL
50
5.5
2.8
NL
50
6.5
2.8
NL
50
5.5 4.2 4.2 (,.0
2.8 2.8 2.8 2.8
NL Nt. NL Nt.
50 50
-
As socia tion of Structural Engineers of the Phil ippines
--. -
...
_. _.
NP 50
.-
CHAPTER 2 - Minimum Design Loads
2-81
Table 208- 11 D Earthquake-Farce-Resisting Structura l Systems of Wood
Basic Seismic-Force Resisting System
no
R
System Limitalion and Building Height Limitation by
Seismic Zone (meters) Zo ne 2
Zone 4
2.8
NL
20
2.8
2.2
NL
20
NA
NA
NA
NA
2.8
2.2
NL
20
6.5
2.8
NL
20
A. Bearing Wall Systems • • •
• •
Li ght- framed wa lls wi th shear panels: wood s tructural panel wa lls fo r s tructures three sto ries or less H eavy limbt!r braced frames where bracing carries Rravi ty load Light-framed wa lls with wood shear panels walls for structures three stories or less All other li gh t framed walls Heavy timber-braced frames where bracing carries gravity load
5.5
..
-
B. Building Frame Systems
•
•
Light-framed walls w ith shear panels: wood structura l panel walls for structures three sto ries or less Ordinary heavv timber-braced frames
The fundamental period T may be computed by using the following equation:
{
T =21[
(208 -10)
I
1
I
I, 1
I
I I
The values of jl: represent any latera l force distributed approximatel y in accordance with the principles of Equations (208-13), (208-14) and (208-15) or any other ralional distributi oll. The c lastic de Oect ions. 0;, shall be calculated using th e applied lateral forces,r,.
I.
Type 1, 4 or 5 of Table 208-9, or
2.
Type I or 4 ofTable 208-1 0.
208.5.2.3.2 Vert ical Distribution The rorces at each level shall be calcu lated usi ng the following equation : (208-1 2)
where the value of C(l shall be dctermined as ill Section 208.5.2.3. I.
208.5.2.3 .1 Ilase Shear
208.5.2.3 .3 Applicability
The total design base shear in a given direc tion shall be dctennincd rrom the ro llow ing equa ti on :
Section s 208.5.1.2, 208.5.1. 3, 20 8.5.2. 1, 208.5.2.2, 208.5.5, 208.5 .9, 208.5.10 'lJ1d 208.6 shall not apply when lIsing the simp lified procedure.
11
I
SE shall be used in Seismic Zo ne 2. III Seis mic Zonc 4, the Nea r- Source Factor, Na. need not be greater than 1.2 if no ne of the following structural irregu lariti es are present :
3C0 w. F .::: __ x 11 '
Structures conforming to the req uirements of Section 208.4.8. 1 may be des igned us ing this procedure.
3e
I
20 2.2 NL where the value of C. shall be based on Tab le 208-7 for the soil profile type. When the , oil properties are not know n in sufficient detai l to determine the soil profile type, Type SD shall be used in Seismic Zone 4, and Type
208.5.2.3 Simplified Desig n Base Shear
ll
V ~--- W
II
5.6
(208-1 I)
th
N(llional Stru ctural Cod e of the PhilipPines 6 Edition Vo turn e 1
2-88
CHAPTEI< 2 -_. Minim urn Design l.oads
1.1 The flexible upper portion shall be designed as a separate structure, supported latera ll y by the rig id lower portion, using the appropri ate values of Rand p. 1.2 The rigid lower portion shall be designed as a
separate structure using the appropriate value s of Ra nd p . The reactions from the upper pOl1ion shall be those detennined from the analysis of the upper portion amplified by the rat io o f the (Rip) of the upper portion over (RIp) of the lower
Where used , !:lid shall be taken equal to 0 .0 l limes the
SIOIY height of all Slories. In Seclion 208.8.2 .8, Equalion (208-20)
shal1 read
and
ex ceed Ca ~11pX' but shall no t be less than
need
O.Sea wpx .
R
and llo shall be laken from Table 208-1 L 208.5.3 Dctcrm.ination of Seismic Factors 208.5.3,1 Determination of llo Fo r spec ific e le ments of the structure, as s pec ifically
identified in this code, the minimum design strength shall be the product of the seismic force overstrength factor
pOl1ion.
not
nn
and the design seismic forces set f0l1h in Section 208.5. For both Allowab le SU·ess Design and Strength Design, the Seismic Force Overslrength Factor, flo. shall be taken from Table 208- I I . 208.5.3.2 Determination of R The value for II shal1 be taken from Table 208·1 I. 208.5.4 Combinations of Structural Systems Where com binations of structura l syste ms arc incorpo rated inl o th e same stru cture, the requirements of this sec tion shall be satisfied. 208.5.4.1 Vertica l Combinations
The value of R used in the design of any story shall be less than or equJI to the value of R llsed in the give n direction for the story above.
208.5.4.2 Combinations along Different Axes In Seismic Zone 4 where a structure has a bearing wall system in only one direction, the value of R used for design in the orthogonal direction shall not be greater lhan thaI used for the bearing wall system.
Any com bination of bearing wall systems, building frame systems, dual systems or moment-resisting frame systems may be used to resist seismic forces in struCtures less than 50 m in height. On ly combinati ons of dual systems and special moment-resisting frames shall be used to resist seismic forces in structures exceeding 50 m in height in Seismic Zone 4. 208.5.4.3 Combinations along the Same Axis Where a combination of different structural systems is utilized to resist latera! forces in the same direction, the value of R used for design in Ihat direction shall not be greater than the least value for any of the systems utilized in that same directi on. 208.5.5 Vertical Distribution of Force The lotal force shall be distribu ted over the hei ght of the stru clure in confom1ance with Equations (2 08-1 3), (208 14) and (208- I 5) in the absence of a more rigorous procedure.
" v =r~ + IF;
Exception: This requirement Ileed not be applied 10 a slory where the dead weight above that stolY is less than 10 percellt of Ihe fatal dead weight a/the Slruc[w·e.
Structures may be designed using th e procedures of Ihis section unde r the following condit ions: The cnli!"!.: stru cture is des ig!1ed using the lowest R or thc tilleral force-res is ting systems used, or I.
(208-1 3)
(= 1
The following Iwo-stagc slatic anal ys is procedures Illa y be used fo r struc tures con forming 20X.4 .R.2 _Itelll 4.
10
Sectio n
Thc con ccntrated force F, at the top, wh ic h is ill additi on 10
r:
I,
shall be dc«::rmined fro m th e equation:
F, =o.07TV
(208-14 )
The value of T used fo r the purpose of calculati ng J-~ shall be Ihe pcriod thaI corres ponds with the desig n base shear
A!:'sociatlon of Structural EIl91ne ers or the Philippines
CHAPTEH 2 - Minimum Design Loads
F x
= (V - F,)w,."-,.
(20S-ls )
"
2-89
208.5,7 Horizo nta l To rsio n al Mo m ent s
L Wihi
Provisions shall be made fo r th e increased shears resuit ing
;=1
from horizontal torsion where diaphragms are not flex ible. The most severe load combination for each
At each level designated as x, the force F, shall be applied over the area of the bu ilding in ac cordance wi th the mass
clemen! sha ll be considered for design.
distribut ion at that leve l. Struc tural di splacements and design seismic forces shall be calculated as the e rfect of forces F, and F, applied at the appropriate levels above the base.
moment resulting from eccentricities between applied
The torsional design moment at a given story shall be the desi gn lateral forces at levels above that story and the vertica l-resisting elements in that story plus an accidental·
torsion. 208,5.6 Ho r izo ntal Dist ri b nti on of Shea r
The design story shear. V.n in any story is the sum of the forces F, and F, above th at story. V, shall be distri buted to the various elements of the vertical lateral fo rce~resi s ti ng system in proportion to their rigidities. considering the rigidity of the diaphragm. See Section 208.8.2.3 for rigid e lemen ts that are not intended to be part. of the lateral fo rc e~
resisting systems.
The acciden tal torsiona l moment shall be determi ned by
assuming the mass is displaced as required by Section 208 .5 .6. Where torsi onal irregularity exists, as defined in Table 20S- 10, the effects shall be accounted for by increasing the accidenta l torsion at each level by an amplification rae tor, A n determined from the following equation:
Where diaphragms are not fl exible, the mass at each level shall be assumed to be disp laced from the calculated center of mass in each direction a distance equal to 5 percent of the building dimension al that level perpendicular to the direc tion of the fo rce under considerati on. The effec t of thi s displ acement on the story shear distri bu tion shall be considered.
Om,/! =
Diaphrag ms shall be considered flexi ble fo r the purposes
O (tIUX
of distribution of story shear and torsional moment when the max imum lateral defo rmation of the diaphragm is more th an two limes lhe average story dri ft of the associated story. This may be determined by comparing the compu ted midpoint in ~pl ane deflection of the diaphragm itself und er lateral load with the story drift of adjoining vertical-resisting elements under equi va lent tribu tary l.te ra l load.
(208 -1 6)
where:
=
the average of the displacements at the extreme points of th e structure at Level x, mOl the maximum displacement at Level x, mm
The val ue of Ax need no t exceed 3.0 208.5.8 Overturn ing
Every structure shall be designed to resist lhe overtull1ing effects caused by earthquake forces speci fied in Section 208.5.5. At any level, the overturn ing moments to be resisted shall be determ ined using those seismic forces (F/ and F,) th at act on levels above the level under consideration. At any level, the incrementa l changes of
the design overturnin g moment shall be di stributed to the various resi sting elements in the manner prescribed in Section 20S.S.6. Overturning effects on every element shall be carried down to the fou ndation. See Sect ions
207. 1 and 208. 8 for combining gra vi ty and seismic fo rces.
,j
!
! i I ,~
National Stru ctural Code of the Phil ippi nes 6'" Editio n Volume 1
I
I, 1
!
._n, o o!- ( .' .' . ..
.;itf'
2-90
CHAP1TF< 2 ... Minimum Design Loa ds
20B.5.8.1 Elements Systems
Supporting
6.
Steel clements designed primarily as flexu ral members or trusses shall have bracing for bo th top and bottom beam fl anges or chords at the locut ion of the support of the discontinuous system and sha ll comply with the requirements of Section 515.6. 1.3.
7.
Wood elements des igned primarily as flexural members shall be provided with lateral bracing o r solid blocking at each end of the clement and at the ro" nection location(s) of the di scontinuous system.
Discontinuous
20B.5.B.l.l General Where allY portion of the lateral load-resisting system is discontinuous, such as fo r vertical irregularity Type 4 in Ta ble 208-9 or plan irregularity Type 4 in Table 208 · 10, concre te, masolllY, stee l and wood e lements supporting s uch discontinuous systems s hall have the design strength
to resist the combination loads resulting from the special seismic load co mbinations of Sect ion 203.5. ~c.epti.oTi$"
I
.t.• :., ' ., .' '.' :: '.. .
th~ qbi1nfithjfj;ljJ.'iech'oif:~03.5 need nbt exce~ the m{lilmum fo.rce·iliat caJl·be·transferred 10 Ihe element . !>y Ihe-:1ciletai-fQti:~'resijrin$ System. ,.
! :· ~;'\" .~· .• '· ,~1;
,;.: . .: : .
20 B. 5.B.2 At Foundation Sec Sections 208.4.1 and 308.4 for overturning moments to be resi sted at the foundation so il interface.
-
2. Qq~.crflf~lqos;:~1fpl!.qrlil!g IigJ:lI-/rame wood ,shear ·>V(JJ):sxstems or ilghJ.;ji-qme sleel and wood structural pa~elshe~r wall sYSiemi:
.
fo r A ll owable Stress Design, the design strcngth may be detennined usin g an allowable stress increase of 1.7 and a resistance factor, ¢, of 1.0. This increase shall not be combincd with the onc- third stress in crease perm itted by Section 203.4, but may be combi ncd with the duration of load increase pennitted in Section 615.3.4. 20B.5.8.1,2 Detailing requirem ents in Seismic Zonc 4 In Seis mic Zone 4, e lcmcnls support ing discontinllous systems shall meet tbe following detailing or mem be r limitfltions:
I.
Reinforced co ncretc or rcinforced masonry clcmcnts designed primarily as axja l~lo ad members shal! compl y wit h Section 42 1.4.4.5.
2.
Reinforced conc rete elements designed primarily as flex ura l members and supporting other than ligh tfram e wood shear wa ll system or light-fra me stee l and wood structural panel shear wall systems shall comply with Sections 421.3.2 and 421.3 .3. Streng th compu tations for portions of slabs dcsigned as support ing elcment s shall include only those portions of th e slab tlw.! comply with th e requirements of thesc
20B.5.9 Drift Drift o r horizontal displacements of the structure shall be com puted where requi red by this code. For both Allowable Stress Design and Strength Design, the Maximum In elastic Response Displacement, 6.,.,. of the structure caused by the Design Basis Ground Motion shall be determined in accordance with this section. The drifts corresponding to the design seismic forces of Section 208.5.2.1 or Section 208.6.5, /), S, shall be detennined in accordance w ith Section 208.5.9.1. To determine /),U, these drifts shall be amp lified in accordance with Section 208.5.9.2. 208.5.9.1 Determination of L1s A static, elastic analysis of the lateral rorce~res i s ting system shall be prepared using the design seism ic forces from Section 208 .5.2. 1. Alternatively, dynamic ana lysis may be performed in accordance with Secti on 208 .6. Where All owa ble Stress Design is llsed and where drift is being computed, the load combinations of Scction 203.3 shall be used. The mathematical model shall comply with Section 208.5.1.2. The resuiting defomlati ons, denoted as 11.<;. sha ll be determined at all critical loca tion s in the structure. Calcu lated drift shall inc lude translational and torsional deflections.
20B.5,9.2 Dct enllinatio n of /)'", Th e Maximum Inelastic Response Displacement, tJ.,\{.
shall be comruted as follow s:
sections. J.
Masolll)' clemcnts des igned primari ly as carrying mcmbers shall co mp ly with 706. 1. 12.4. Item I. and 70g .2.6.2.6.
Sec tions
4.
Masonry cl ements des ign ed primaril y as ncxural members shall compl y with Sect ion 70X.2 .6.2.5.
5.
Steel clemc nts designed prill1;lrily as :lxi'II-load membe rs sha ll compl y wilh Sec ti ons 5 15.4.2 il nd 515.4 .3. Associatloll
(208- 17)
' L~ial - I o ad
() f
£.xception:
~.:.
Alternatively, 6. M may be :computed by Ilonlinear time his/DI)' analysis in accordance with Sec/ion 208.6. 6. The analysis lIsed to determi nc the Ma ximu m In clastic Response Displacement AM shall considcr P6 effecls.
Stfllclu(tll EngIneers of thA
Phiti pprn e ~
CHAryrEF, 2·- Minimum D"sign Loads
208.5.10 Story Drift Limitation Story drifts shall be computed using the Maximum Inelastic Response Displacement, 11 M .
principles of dynamics.
208.5.10.1 Calculated
section
Calculated story drift llsing !!.'d shall not exceed 0.025 times the story height for structures having a fundamental period of less than 0.7 sec. For structures having a
fundamental period of 0.7 sec or greater, the calculated ,tDlY drill shall not exceed 0.020 times the stOIY height.
2-91
representation and shall be performed using accepted
Structures that arc designed in accordance with this
shall
comply
with
all
other
applicable
requirements of these provisions.
208.6.2 Ground Motion The ground motion representation shall, as a minimum, be one having a I O-percent probability of being exceeded in
Exceptions:
50 years, shall not be reduced by the quantity R and may be one of the following:
1.
1.
l'lzese drift limits may be exceeded when it is demonstrated that greater drift can be tolerated by both stmctural elements and nonstructural elements that could affect life safety. The drift used in this assessment shall be based upon the Maximum Inelastic Response Displacement, LlM .
2.
There shall be no drift limit in single-story steelframed structures whose primaty use is limited to storage, jactories or workshops. Minor accessOlY uses shall be allowed. Structures on which this exception is used shall !lot have equipment attached to the structural Fame or shall have such equipment detailed to accommodate the additional drift. Walls that are laterally supported by the steel frame shall be designed to accommodate the drift in accordance with Section 208.8.2.3.
en
acceleration ordinates shall be multiplied by the acceleration of gravity, 9.815 mfsec 2•
2.
A sitewspecific elastic design response spectrum based on the geologic, tectonic, seismologic and soil characteristics associated with the specific site. The spectrum shall be developed for a damping ratio of 0.05, unless a different value is shown to be consistent with the anticipated structural behavior at
the intensity of shaking established for the site. 3.
208.5.10.2 Limitations The design lateral forces used to determine the calculated drift may disregard the limitations of Equation (208-6) and (208-7) alld may be based 011 the period determined from Equation (208-10) neglecting the 30 or 40 percent limitations of Section 208.S.2.2, Item 2.
An elastic design response spectlllm constructed in accordance with Figure 208-3, using the values of and C. consistent with the specific site. The design
Ground motion time histories developed for the specific site shall be representative of actual earthquake motions. Response spectra from time histories, either individually or in combination, shall approximate the site design spectrum conforming to
Section 208.6.2, Item 2. 4.
For stJ1lctures on Soil Profile Type Sr, the following requirements shall apply when required by Section
208.4.8.3. Item 4:
4.1 The ground motion representation shall be developed in accordance with Items 2 and 3.
208.5.11 Vertical Component 4.2 Possible amplification of building response due to the effects of soil-stl1lcture interaction and
The following requirements apply in Seismic Zone 4 only. Horizontal cantilever components shall be designed
lengthening of building
for a net upward force of O.7Ca/~r In addition to all other applicable load combinations, horizontal prestressed cOlllponents shall be designed using not 1110re ill;!n SO percent of' the dead load for the gravity load, alone or in combination with the lateral force efJCds. 208.6 Dynamic Analysis Procedures
period
caused
by
inelastic behavior shall be considered.
s.
The vertical component of' ground motion may be defined by scaling corresponding horizontal accelerations by a factor of (wo- thirds. Alterna;ivc factors may be used \vhen substantiated by ~itew specific data. Where the Near Source Factor, Nil' is greater than 1.0, site-specific vertical response spectra shall be used in lieu of the factor of twothirds.
208.6.1 General
208.6.3 Mathematical Model
Dynamic analyses procedures, when used, shall conform to the criteria established in this sectiol1. The analysis shall be b;lscd 011 an appropriate ground Illotion
A mathematical model of the physical structure shall represent the spatial distribution of the mass and stiffness of the structure to an extent that is adequate for the lh
Nation;:·]1 Structural Code of the Philippines G Edition Volume 1
2-92
CHAPTEIi: '2 ..
Miflllllllnl Oesl~Jil
l.oacis
calculation or the significant rcntures of its dynamic response. A three-dimensiona l model shall be used for the dYlllllllic analys is of sll1lc(ures wit h highl y irregular plan config urat ions such as those havi ng a pla n ilTegularity detl ncd in Tab le 208- J 0 and hav ing a ri gid or semi- rig id diap hmg m. The stiffn ess properti es used in th e analysis and ge neral mathematica l modeling shall be in accordance \-vith Section 208.5.1.2 . 208.6.4 Description of Analysis Procedures 208.6.4.1 Hes!,ollse SpectrullI Allalysis An elasti c dyn.lI mic ana lys is of a st ru cture uti lizing the peak dynamic response of all modes hav ing a signifi cant contri bution to total stmclura l response. Peak moda l responses arc calcu lated usi ng the ordinates of the appro priate response spectrum curve which correspond to th e modal periods. Maximum mod<1 1 contribut ions arc combined in a stat istical manner to oblHin
combined by recognized methods. When lhr eedimcnsiona l modcls arc used fo r analysis, mo dal interactio n efleClS shall be considered when co mbining modal IlH1X im<1. 208.6.5.4 Rl'dutlion of Elastic Response Parameters for Design Elastic Response Parameters may be reduced for purposes of design ill acco rda nce with the foll owing itcms, \\. itll th e limitation th at in no case shall th e Elas ti c Response I)aramciers b ~ reduced sllch thaI the co rresrond ing des ign base shear is less th an th e Elasti c Response Base Shear divided by Ihe va lue o f R. I.
2.
208.6.4.2 Time History Analysis
An analysis of th e dynamic response of a structure at each increment of time when the base is subj ected to a specific ground Illotion time history.
For all regular structures where the ground motion representalion comp lies wilh Seclion 208.6.2, Item I, Elastic Response Parameters may be reduced such that the correspond ing design base shear is not less than 90 percent o f the base shear detenn ined in acco rdance wilh Section 208.5.2. For all regul ar strucrures where the ground motio n reprcscntati on compli es with Sect ion 208.6.2 , hem 2, Elastic Res ponse Parameters mny be reduced such that the co n esponding design base shear is not less than 80 percent of the base shear detelmined ill accordance with Section 208 .5.2 .
208.6.5 Re sponse Speclrll III Analysis
3.
208.6.5. 1 Res ponse Spectrum Represe ntation and Interpretation or Results The ground motion represl'll!
The corresponding reduced design seismic fo rces sha ll be used for design in ~ccordance wilh Section 203.
The base shCHr for a given direct iol1 . de term ined usin g dynamic analysis must not be less thall th e value obtained by the equivalent lateral force meth od of" Section 208.5 .2. In this case, alt co rresponding rC!-ipo nse P,lr(l1l1ctcrs arc adjusted pro portiona tely.
f
208.6.5.5 Direclion a l Errecls
Directiona l effec ts fo r horizontal groun d Illotion shall con form 10 the req uirements of Sectio n 208.5. 1. The effects of vert ica l ground moti ol1s on horizontal cantilevers and pres tressed elements shall be qmsiciered in accordance with Section 208.5.1 t . Altcrnately. vertical seismic re s p o ll s ~ Illay be determined by dynamic response me thods ; in no case shall the response uscd for design b(.: Jess than that obtllinc<1 by the slatic mc th od.
208.6.5.2 Number or Modes
TilL' requ irc mcnt of Section 20K.6.4. 1 II1<1t all signifi cant modes be inc ludcd may he sCltisfied hy demonstrating lhat for the modes cOJlsidered.
208. 6.5.6 TO"sion The analysis sllflll HCCO Ulll ror to rsionall'flcc{s. including ;Jct:jdcn t ~1 torsional efrects as presc ribed in Sect ion 20X.5.7. Where thl'cc·dimcn:.;ional mode-Is :lrc uscd for ana lysis, erfects of accidcnwl torsion shall be accou nted fiJI" by appro priate adjust ments in the model slich il f; adjust men t of" mass loca lions. or by equ ivale nt statio: procedures such as pro vided in Sect ion 208.5.0.
The pcn k member j()]"ces. di sp lacements. slory f()fI:cs, story shears ;llld base reactions I()r" l~ ach mode shall be Assod:ltlon of Structural
Eil~J l ntw r s
of the PhlilPPll leS
CHAVITf, 2 - Minimum Design Loads
208.6.5.7 Dual Systems
2,93
208.6.6.3 Nonlinear Time History Analysis
Where the latera! forces arc resisted by a dual system as defined in Section 208.4.6.4, the combined system shall
208.6.6.3.1 Nonlinear Time History
be capable of resisting the base shear determined in
Nonlinear time history analysis shall meet ;bc requirements of Section 208.4.10, and time histories sblll be developed and results detennined in accordance with the requirements of Section 208.6.6.1. Capacities··,eI characteristics of nonlinear elements shall be modci<:d consistent with test data or substantiated analy
accordance with this section. The moment-resisting frame
shall conform to Section 208.4.6.4, Item 2, and may be analyzed using either the procedures of Section 208.5.5 or those or Section 208.6.5.
208.6.6 Time History Analysis 208.6.6.1 Time History Time-history analysis shall be performed with pairs of
appropriate
horizontal
ground-motion
time-
history
components that shall be selected and scaled from not less than three recorded events. Appropriate time histories shall have magnitudes, fault distances and source mechanisms that are consistent with those that control the design-basis earthquake (or maximum capable earthquake). Where three appropriate recorded groundmotion time-history pairs are not available, appropriate simulated ground-motion time-history pairs may be used to make up the total number required. For each pair of horizontal ground- motion components, the square root of the sum of the squares (SRSS) of the 5 percent-damped site-specific spectrum of the scaled horizontal components shall be constructed. The motions shall be scaled such that the average value of the SRSS spectra does not fall below 1.4 times the S percent-damped spectrum of the design-basis earthquake for periods from O.2T second to I.ST seconds. Each pair of time histories shall be applied simultaneously to the model considering torsional effects. The parameter of interest shall be calculated for each timc.- history analysis. If three time-history analyses are performed, then the maximum response of the parameter of interest shall be used for design. If seven or more timehistory analyses are performed, then the average value of the response parameter of interest may be used for design.
208.6.6.2 Elastic Time History Analysis Elastic time history shall conform to Sections 208.6.!, 208.6.2, 208.63, 208.6.5.2, 20S.6.5.4, 20S.6.5.5, 208.6.5.6,208.6.5.7 and 208.6.6.1. Response parameters from clastic time-history analysis shall be denoted as Elastic Response Paramcters. All clemcnts shall be designed llsing Strength Design. Elastic Response Parameters may be scaled in accordance with Section 208.6.5.4.
208.6.6.3.2 Design Review When nonlinear time-history analysis is used to justify,. . structural design, a design review of the lateral- force· resisting system shall be performed by an independcd engineering team, including persons licensed in ihc appropriate disciplines and experienced in seisrnic analysis methods. The lateral-foree-resisting system design review shall include, but not be limited to, the following: I. Reviewing the development of site·specific spectra and ground-motion time histories.
2.
Reviewing the preliminary design of the lateralforce-resisting system.
3.
Reviewing the final design of the lateral-forceresisting system and all supporting analyses.
The engineer~of~record shall submit with the plans and calculations a statement by all members of the engineering tcam doing the review stating that the above review has been performed.
208.7 Lateral Force on Elements of Structures, Nonstructur.1 Components and Equipment Supported by Structures 208.7.1 Gener.1 Elements of structures and their attachments, permanent nonstructural components and their attachments, and the attachments for permanent equipment supported by a structure shall be designed to resist the total design seismic forces prescribed in Section 208.7.2. Attachments for noor- or roof-mounted equipment weighing less than 1.8 kN, and furniture need not be designed. A ttachments shall include anchorages and required bracing. Friction resulting from gravity loads shall not be considered to provide resistance to seismic forces.
National Structural Code of the Philippines 6
111
Edition Volume 1
2-94
CHAPTEF~
2 -' MlOimwn Design l.oads
When the stmctural fa il ure of Ihe lateral-force-resist ing systems of nonrigid equi pment would cause a life hazard, such systems shall be designed to resist the seismic fo rces prescribed ill Section 208.7.2. When permissible design strengt hs and oth er accept ance criteria arc not contained in or referenced by this code, such criteria shall be obtained from approved national standards subject to the approval of th e building official.
208.7.2 Desigll for Total La tHai Force The total design lateral seismic fo rce, FI" delenn incd from the fol lowing equation:
Forces dctcnnillcd lIsing Equation (20 r.:-:,·j \..>:. t·: .-, .(;; shall be lIsed to design members and cO IH;\'·c! j ;".~') (:;;11 tra nsfer these fo rces to Ihe scismic·n""'· '1;;' ...: .... ~i....:l -". M embers and connection design Shidi l.i 'tC 11,.:. ;·' f'IJ co mbi nati ons (11)(1 rac tors speci fi ed in S~ · C!ii.)n . ~0 3.3 ll l" 203 .4 . The Reliabi lity/Redundancy Factor, !), may be taken eqLlal to 1.0. For appli cabl e (orees and Component p,.' : ' O Jl ': (· Modification Facto rs in connectors for c;\"l<..~ r i )l p. ;: ;.j diaphrag ms, refe r to Sections 208.8.2. 3, 2tnU\./ . .. Hi
shall be
208.8.2.8.
(208 - 18)
result in [he 1110st crilicalload ings for design .
f-orces shall be appl ied in the horizontal di rc<.:I!OH::, \'.Ih il:!:
Altern atively, Fp may be calculated using the fo llowing equ ation:
aCI( II)WP P 1 R +
F = P P
1I
I'
) ---L
(208-1 9)
"I"
Except that I'~' shall 1I0t be less than O.7C,/pWp and
need not be more than 4C~JpJ1~) . where :
h.f
the clement or componcn! atta chme nt elevation wiLh respect LO grade. fi x shall n01 be taken less tha n 0.0 . h,. = the stnlClure roof elevation wit h respect 10 grade. n,l = the in·slruc ture Componelll Amplification Factor that varies from 1.0 to 2.5. =
A va lue for "" shall be selecled from Table 208-12. Altemalively, this factor may be detenn ined based on the dynam ic properti es or e mp irical da ta of the co mponen t and the structure thai supports il. The va lue shall not be taken less th an 1.0. Rp is the Componenl Response ·Modification Factor that shall be taken from Table 208-1 2, except that Rp for anch orages shall eq ual !.5 for shall ow ex pansion anch or bo ilS, shallow chem ical anchors or shallow cast·in·p lace anchors. Sha llow anchors are th ose wit h ti n embedme nt IcngtlHo·diamcter ratio of less tha n 8. When anchorage is co nstructcd ofnonducti lc mate rials, or by lise of adhesive, Rp shall equal 1.0.
208.7 .3 Specifying Lateral Forces Design speci fi ca tions for equi pment sha ll either spcci r/ Ihe design lateral fo rces prescri bed he rein or reference these pro visions.
208.7.4 Relative Motion of Equipment AII. chment, For equipment in Categories I and II bui ldin gs as dcfincti in Table 103 · 1, th e lateral-force design ~; h a l! considc) (l,c effec ts of rela tive motion of th e poin ts of attachmen l to the structure, usi ng the drift based upon AM. 208.7.5 Alternative Designs Where an approved national stand ard or approved physical tes t dala provide a basis ror the earthquake· resis tant design of a particular type of equipment or other nonstructural component, sllch a standard or data may be .lcccplea as a basis for design of the items wit h thc fo llowing limita ti ons:
J.
These provisions sha ll prov ide minim um va lues for th e design of the anchorage and th e mem bers an d connections th at transfer the forces to th e seismicresisting system.
2.
The force, I;~h and the overturning mo ment used in the design of th e nonstl1lctural component sh;\!1 ,i' . be less than 80 percent of the vn lucs that WO\i ~.: obtained lIsing these provisions.
The design latcnd forces determined using Equat ion (208· I R) or (208- 19) sha ll be distributed in proport ion I() the mass dis Lri bulioll of fhe element or component.
Associat ion of Structural Engineers of the Philippines
CHAPTER 2 - Minimum Design Loads
2-95
Table 208-12 Horizontal Force Factors, ap and Rp for Elements of Structures and Nonstructural Components and Equipment - - - - - -- _._- - - - - - - - - - - - - - - _ . _ --- -- - - - - - , - - , - - - - - - - , - - - - - , Category Element or Component ap Rp Footnote ~----.---
--------------------'-----'-------'---!-----I I. Walls including the following: ................... __ ..
a. Un braced (cantilevered) parapets
2.5
3.0
._-_ . .._-- -
.....
b. Exterior walls at or above the ground floor and p_~r:.~p~~~ br~~e~_ a~.oy~th_~ir__~~~1t~I:~~_f_ g~~.~jty
1, Elements or Structures
1.0 ._
. ..
--
c. All interi6r~bcaring and non-bearing walls
2. Penthouse (except when framed by an extension of the stmcturai frame) 3
3.0
. CO ,l;1cci;O-[~·;-'f~·~-p-~~'f;~b;:i~-~tcd-st;;;-~iu~·a"j -ci ~~~;e~-t~-~ti~c~--walls. See also Section 208.7.2
I. Exterior and interior oll1amentations and appendages.
2
-- -------~ ---
1.0
3.0
2.5
4.0
1.0
3.0
2.5
3.0
3
--------
... _.....-
2. Chimneys, stacks and trussed towers supported on or
- -- --
2
p~oj.~~!.ing_.~_~2.'::'~!l!£.~~_2r
_.~ __ ......_".___._ . _. . ~ .. __ ..._ ...... __._ __ ~_._.~~ __.__ .. _ a. Laterally braced or anchored to the structural frame at 2.5 3.0 .~. P5?it_)t_~~l~~ _t!1~i~ __ c_~.!.~~~r~ __()f ~!:l~.~.~" _......_..... _ ..____ " .......__ .. ___ .~_. _.~ .. _....___ ._____ _ b. Laterally braced or anchored to tbe structural frame at 1.0 3.0 O!' ,~bov.c .theil: centers o.f m~ss _. .." ._...~ .. __ ~ .. __._,_. __._____________ ~. __.__ _
3. Signs and billboards 2.
NOllstructural Components
2.5
3.0
4. Storage racks (include contents) over 1.8 m tall. 2.5 . .. --------.-----5. Permanent floor-supported cabinets and book stacks more 1.0
4
4.0
- -··---·-··t----~
3.0 5 tl.la_t~JJ.m_ in ..l!~.jg!.l~. __ (i!lclud~_c:()n!e~~s). __ . ______;____.. _._.. _. _.... __._ .__._______ _ _1 6. 0nchorage and lateral bracing for suspended ceilings and 1.0 3.0 3, 6, 7, 8 hght fi.~~_u~es ........__ .._____ .. _. __ ... _______--1 7. Access floor systems
4,5,9
3.0
1.0
---- - -
- ~ ~- . ~--
8. Masonry or concrete fences over 1.8 m high
3.0
1.0 ..
9, Partitions, .~___;_~-_:_;c___;- -- .- - . -
1.0
-- . --~- - -.- - .----.-- -
---_._-
I . Tanks and vessels (include contents), including support
systems.
1.0
I
2. Electrical, mechanical and plumbing equipment and associated conduit and ductwork and piping.
-- ---- -_ ..
f---3.0
.
I
1.0
I 3. Any flexible equipment iaterally bt~aced or anchored to the 2.5 3.0 stnlctural ft~atl.lC at a point_ ~e!.ow tl~~_t~_~~.~!t.~r ofmas~ 3. Equipment 4. Anchorage of emergency power supply systems and essential communications equipment. Anchorage and support systems for battery racks and fuel tanks necessary 1.0 3.0 for operation of emergency equipment. See also Section 208.7.2 5. Tcmporary containers with flammable or hazardous 3.0 1.0 _ _ __.___ ._~ _ _.~ ___._____.._.!.1.1,ltcriaJs._____ _ _ _ ~ ___..~~ ___,___._ _._______+_----1---
CompOnCll\S
I. Rigid comroncnts with ductile material and attachments.
1.0
3.0
2. Rigid components with nonductile material or attachments
1.0
1.5
2.5
3.0
2.5
1.5
J. Flexible components with ductile material and
altacllmcllts. 4. Flexible components with nonductile materi,!! or attachments.
1h
National Structural Code of tile Philippines 6 Edition Volume 1
--·--··--~
5, 10, ll, 12,13,14, 15, 16
3.0
..... 5-:io,T4:-
_ .. -
4., Other
_-
3.0
.. 11,1.2 _ 17, 18
- --
1
19
CHAPTEI~
2-96
2 ,-. Minimum Design Loads
Notes/or Table 208, J2 I See Section 208.2 Jor definitions ojj7exible componellls and rigid component,I'. I See Sectioll 208.8.2.3 and 208.8.2. 7./ar COIlCl'ele (Jnd ma.wllIy 11'(/1/.\' and Sectioll 20S. 7.2 for cOllnccfio/lsjiu" pond wl/nee/orsji),. jWllc{s. J Applil'S to Sci,l'mic ZOIl(,S 2 and 4 only.
Ground supported steel storage racks lIIay he designed IIsing Ihe prol'i.\"jo/l,I' (~f'S(,Cfi(Jl/s 208.1), Lood and /"esi.\'{III1C1'jilC/o/" design /lilly be ".\wl JiJr the design oj cold.jonned sfeel 1111'111/;<'1;\', pl"(JI'ided sei,\"lIIi(' dO'ign /hrce.\" are i'ill/o/ to or grea/e!" 11/(111 {hose ,Ipeei/ied ill Sec/ioll 208.7.2 or 208.9.2 as appropriate. OI1/Y anchorage or resfrail1l.I' /leed be designed
Ceilillg weight shall include all Iig"fJixfures and olher equII)lIIl!n! or parliliollS Ihal are lalemlly xupporled II.!' Ihe ceiling For purposes of determilling fhe .I·e/slllicjoree, (l ceiling weight o/nolless (han 0.2 kPa shall he used.
6
1 Ceilings eonslrucled of lath and plaster or gypsum board screw or lIail (Jtlached to slI.Ipellded memher.l· fh(lt supp()rt 0 c('iling {It 0111' level extelldiJlgfrom wall to wall need not be ana~!'zed, provided (he walf,l' (lre I/of over 15 lIIelers oparl. Light jixrures and /l/eclwllical services illstalled ill metal slI.Ipellsioll sy.l'lel/ls for aco/lstical IiII' (llId lay-in panel cei(ings shilll he independently supporledJrolll Ihe SIn/crure abol'l! as specified in VBe Standard 25-2, Parr II/, W,Ior accessjloor systems shall be the dead /otl(1 of the (lCCessjloor system pIllS 25 percenf'q(lhe/loor livc load pIllS a 0.5 kPo parlilioll load allowal/ee.
Y
Eqllipment includes, but I:V /lot limited to, boilers, chillers, heal exchallgers, pumps, tlir·jwlldling IIl1its, cooling tOl\'ers, control pal/e/s, motors, switchgear, trallsformers and life-safety equipment. II shall indude major cO/lduit, dUelillg and piping, which serl'ices such machill(")' and equipmenl and/ire sprinkl£'r systems. See Sec/ioll 208. 7.2I()r addilioll(ll rcquireml'III.I'jor t/e/{'/'minillg ar/i)}' nonrigid or flexibly mO/lnted eq!(lj)ment.
III
II
Seismic res(raints may he omilledFom pipiflg and duct supports ((all fhe/rAlowing condiliOlls are sa{i.~·lied:
/II
Latera! molioll (?((he 1)lI)illg or duel lI'il! not calise damaging impacl lI'i[h Olher systems
IUThe piping or due[ l:~ made of ducri!e materia/willi ductile connections. II J Latera!
motiOIl of rhe piping or duct does not cause impact I?fFogife appurlentlnces (e.g. , sprinkler hem/s) with pll)ing or structllral member.
(11/.1'
olher eqllipmenl.
'14 Lateral mOliOIl o/lhe PII)illg or duct does 1I0t cause loss q( system vertical support. 11.1 Rod-III/lip, 116 Support
Seismic res/milliS may be omilledji'Olll electrical raceways, meh as cable trays, con(hlil and Ims ducts, i/allthej(}/fllwing ('Oll(/iliol/.\· (Ire sali·Vied:
11
I.' 1 I.' "
Lateral 1II0lioll of [he Nl('C'II'ay wi/lllol calise damagillg impact lI'ilh olher syslems L(l/eral moliOIl o/the raceway does /lot cause loss (?fsy.~tem vertica! SlippOr/.
I.' J Rod-hllng 1.'.
J.I
I.
supports oIless than 300 mm in length halle top cOl/nections Ihm callnOI del'elop mOlllenfs.
membcn cantile\'ered lip Fall! IhC'/loor are checkedj(!r slability.
SlIpporls o(less than 300
IIIIIJ
in lenglh hOI'<' rop cOlllleuiolls Ilwl callnot del'<,loll //lOll/ellis
members ct/I/tilel'ercd upFoIII fhejloor are checked/or siahilil)'
Piping ducls (lnd electrical race\I'ays, which IIIIIS[ he /III/Cliol/o! Iollo\\'ing all e(luhquoke. spllnlling /J('/lI'l'ell di[li>rell/ hllildillgs or slructural ,1),.1'/('111.1' .1'//111/ be sI41iciellilyflexible 10 withstand Idatil'" lI1olio/! oj.I'I{/lporl POilllS assllming out-or/lhIlS" /IIOliU!l.I· Vibration isolalors supporting equipment sil(1/1 he designcd j()r hl/eml l!lads or reslmined /iml/ displacing laterll/~1' hy oilier 111('(111.1' Reslrai!1l shall also be pnll'ided. \I'lliell limits valiea! displacelllcnt. .weh that hI/era I reslraillt.l· do nOI hecome diwngoged. (1/, (111(/ R,,/iJ/' eqllll)ll1el1l supporlcd (In I'ihration I:wiators shall be lakell as 2.5 and 1,5, reSpeClil'e!y, except Ihal [( Ihe isolalioll mounling Fame is supported by shalfow or e:q)(ll/sioll allchor,~, Ihe design forces .f<)r fhe (/lIcllor,\' calculaled hy Equalion (20!) . 18).or (208 - /9) (incl/lding limits), shalf be additionally II1Uflll)/ied by/actor (42.0.
15 Equipmellt anchorage sha/lIlO{ be designed such tllatloads are re.~isfed by g/'Q\Jityjikliol! (e.g., /ricriol/ dips). 16 Expansion (I/lcllor,\', which are required to r('siSI seismic loads in lellsioll ..\'hal/ 1101 be present. J1
II,H'd
where operational \'ihNlling loads are
/.lo\'('lIIen[ (?( compon('nts wilhill dectrical cllbillet.I·, rack,ol/d skid-mounter! equipll/{'II! (ll/d portiOIl,I' (:/skid-lIIl11l11led e/ectrOIlWc/llll1iclIl equipmenl (hat ilia.\' calise damage 10 other compollents /).1' di.lpillcing, shl/If he reslrirled lIy IIl1llchlll('l/t 10 a!lchored ('(/'IIIIIII{'III or support/rallies.
I."
/Jatteries
IV
5;eismic reSlrllillls lIIoy incll/dc .I'/raps, chaillS. holls, harner.l· or olher lII('chollislIIS fhat pn'I'(,I/{ sliding. /ol/ing alld IIr('(lch ojrllJ/lllilllllcll1 I!I/lollllllab/e and toxic materials. Friction/illn's IIf(lY I/of he IIsed 10 r('.I'i.l'1 lotl'rof III(/(lI' ill III(' l'e.I'lroilils IIntes.\' flosilil'{' II/,lil; restrailll i.1 provided which {'IISIII'('S [hal fhc/i'ictioll/or('es act c()/llil!l/O/ls~l'.
Oil
racks .1'110/1 h(' restrail/cd agaill.H
IIIOVellll'l1!..i1l
aI/ direcliOIl dll(' 10 ('orlhqurlke(o/,c('.\'
Association of Slructuml EIl~Jille8rs of the Philippines
CHAF'TEf~
; 208.8.1 General ;' All s(nlctural framing SYSICIllS sha ll comply Wilh the i requirements of Section 208.4. Only the elements of the ':" designated scismic-force-resisting system shall be lIsed to resist design forces. Thc individual components shall be designed to resist th e prescribed design seismic forces acting on th em. The components shall also comply wit h the specific requirements for the material contained in ~ Chaplers 4 through 7. In addition, slich framing systems and components shall comply with the detailed system design requiremcnts contained in Section 208.8. !(
All building components in Seismic Zones 2 and 4 shall be designed to resist the effe cts of Ihe seismic forces prescribed herein and the effects of gra vity loadings from
I
208.8.2.1 Detailing for C ombinations of Systems
For componcnts common 10 different structural systClns, the more resl rictive dctaillng requircmen(s shall be used. 208.8.2.2 Connections
Con nections that resist design seismic forces shall be designed and deta iled on the drawings. 208.8.2.3 Deformation Compatibility All stnl ctural framing elements and their connections, not required by design to be part of the lateralMforee-resisting
Consideration shall be given to design for uplin effects caused by seismic loads.
system, s hall be designed andlor detailed to be adequate to mainlain suppor! of design dead plus live loads whell subjected to lhe ex pecled deformations caused by seismic forces . P6 effects on such clements shall be considered. Ex pected deformations shall be detcnnill ed as the grea ter of the Maximum inelastic Response Displacement, 11 M • cons idering PI1 effecls determined in accordance wit h Section 208.5.9.2 or the defollnation induced by a story drin of 0.0025 limes the story height. W hen computing
fn Seismic Zones 2 and 4, provision shall be made for th e effects of earthquake forces actin g in a direction other than the principal ax es in each of the following circumstances: I.
Ir
shown in Table 208-1 1. Each type is subdi vided by the types of vCl1icaJ c lemen Is used to resist lateral seismic forces. Special frBming requirements arc given in Ihis section and in Chapters 4 through 7.
dead and flo or live loads.
I
I
The structure has plan irregularity Type 5 as given in Table 208-1 0.
2.
i 3.
The stnlcture IlHs pJan irregularity Type I as given in
expecfed deformations, the stiffening effect of those clemen ts not part of the laleral-fo rce-res isting system
Table 208-10 for both maj or axes.
sha ll be neg lected.
A column of a structure forms pat1 of two or intersecling lateral-forcc~rcs i sling systems.
1110rc
~ception:
~ the
axial load ill the column due to seismic forces ~f'ting in either direction is less than 20 percent of the ~olunlll axial load capacity. The requirement that orth ogona l effects be considered may be sat is fied by designing slich elements for 100 perccnt of thc prescribed design seismic forces in one direction plus 30 perce nt of th e prescribed design seism ic forces in the pi! rpcndicular direction. The combination requiring th e greater com ponent strength shall be used for design . AIIl'rnat ively, the erfects of the t\I./O ortho!.!o nal directions may be combincd 011 a square rOOI of thc~ SUIll
or
of the sqllorcs (SRSS) basis. When the SRSS mcthou combining directional c ffecl s is used, eilch Icrm compulcd shall be assi gned th e sign Ihat will result ill (he 1110st
conservative result.
For clements not 1'<111 or lhe lateral-force-resisting system, the forces inducted by the expected delonnation may be co nsid ered as ultimate or factored forces. When co mputing Ihe forces induced by expected deformations, Ihe restraining effect of adjoining rigid structures and nonslructural elCIl.1enlS shall be cons idered and a rational va lu e of member and restraint stiffness shall be used. Inelasti c dcfonnations of members and connections may be considered in the evaluation. provided the assumed ca lculn tcd capacities
National Struc tural C()(~c: of ll'l~: PhiliPPines
L
2··9i'
208 .8.2 Str uctural Framing Systems pour typcs of general building framing systems defi ned in Section 208 .4.6 are recognized in th ese pro visio ns and
; 208.8 Detailed Systems Design Requirements
I
;> - Minimum DElsiqn I.oads
(J lh
Edi ti on Volul'llo 1
2-9B
CHAf'TEH 2 .. MirlHmml Design Loads
208.8.2.3.1 Adjoining Rigid Elements
Moment-resisting frames
and shear walls may be
enc losed by or adjoined by more rigid clements. provided it can be shown that the participation or failure of the
A positive connection for resist ing horizontal forl,.:c aCling parallel to th e member shall be provided for each h( am , gi rder or truss. This force shal l not bc less thall (L ·). ..../ times the dead plus live load.
more rigid elements wi ll not impa.ir the vertical and lateml- load-resisting abi lity of the gravity load and ' lateral-fo rce-resisting sys tems. The eflccts of adjoining rigid clements shall be considered w'l':en assessing whe ther a structure shall be des ignated rcguial or ilTcgular in Section 208.4.5. 208.8.2.3.2 Exterior Elements
Exterior non-bearing, non-shear wall panels or elements tiltH are attached to or enclose the exterior shall be designed to resi st the forces per Equation (208-1 8) or (208-19) and shall accommodate movemen ts of the struct ure based on 6 M and temperalure changes. Such clements shall be suppo rted by means .of cast-in-place concrete or by mechanical connections and fasteners in accordance wi th (he following provisions:
I.
Connections and panel joints shall allow for a relative movement between stories of not less than two times :-I tOly drift caused by wind, the ca lculated story drift based on 11M or 12.7 mm, whichever is greater.
2.
Connections to permit movement in the plane of the panel for story drift shall be sliding connections using slotted or oversize holes, connections that penni! movement by bending of steel, or other connections providing equiva len t sliding and ductility capacity.
J.
Oodies of connections shall have sufficient duct ility and rotation capacity to preclude fnlcturc or the conc rete or brittle failures at or ncar welds.
4.
The body of the connection sha ll be designed for the force determined by Equation (208-19), where lip ~ 3.0 and "" ~ 1.0.
S.
All fasteners in the connecting syste m, such as bolts, inserts, welds and dowels, shall be designed for the forces determined by Equation (208·19). where R,• ~ 1.0 and a,• ~ 1.0.
6.
Fnstcncrs embedded in concrete sh,1I1 be attached 10, or hooked around, reinforcing steel or otherwise termi nated to cfTcctivcly 'transfer forces to the rcinfo rcing stcel.
208.8.2.4 Collector Elements Collector e!ements shall be provided that are capable of transferring the seismic forces originating ill o!hn portions of the struc tu rc to the clcment providing : he resistance to those forces.
Collector clements, splices and their connc<.:lio1":<: 10 resisting clements shall re sist the forces d elen ni~lcd ;11 accordance with Equation (208-20). In addition. co llector clements, splices, and the ir connections 10 resisting elements shall have the design strength to resist the combined loads resulling from Ihe special seismic load of Sect io n 203.5. Exception:
/11 st/velures, or portions thereof, braced entirely by lightframe wood shear walls or light-frame steel and wood stmctllral pallel shear wall systems, col/ectol" elen;(,l1ts, splices and connections to resisting elements /l eed olil)' he designed to resist forces in accordance with Equutioli (208-20). The quantity £.\1 need not exceed the maximum force that can be transferred to th e collector by the diaphragm Hnd other clements of the lateral-force-resisting system. For Allowable Stress Design. the design strength may be determined using an allowable stress increase or 1.7 and iJ resistance factor, $. of 1.0. This increase shall !lot be combined with the one-third stress increase permitted by Section 203.4, but may be combi ned with the dura tion of' load increase permined in Seclion 615.3.4. 208.8.2.5 Concrete Frames
Concrete frames required by design to be part of the lateral-force-resisting system shall conform 10 the following: I.
In Seismic Zone 4 they shall be specinl 1ll0llwnt· resisting frames.
2.
In Seism ic Zo ne 2 th ey sha ll, as a minimum, be inlcrmediatc moment-resisting framcs.
208.8.2.3 Tics a nd Continuity
208.8.2.6 Anchorage of Concrete or Masonry W:tIlS
All parts of a stntclurc shall be intercollnectcd and the conncctions shall be c
Concrete or masonry wa lls sha ll be anchored 10 ;1/ 1 noo l · and roofs that provide QUI-or-plane lateral support of" the wa ll. The anchorage shall provide a positive direct cnn neclion hetwcen the wall and fl oor or roof COII!'ltruc{ioll c"pab le of resisti ng the largcr or the horizontal forces spec ified in this section
Assol.iatJon of Structural EngIneers o f IIH~ PtlilipPJf10S
CHAPTEf, 2 -- Minimum Design Loads
diaphragm to wall anchorage using embedded straps shall have the straps attached to or hooked around the reinforcing steel or otherwise terminated to effectively transfer forces to the reinforcing steel. Requirements for developing anchorage forces in diaphragms arc given in Section 208.8.2.8. Diaphragm deformation shall be considered in the design of the supported walls. 208.8.2.6.1 Olll-of-Plane Wall Anchorage to Flexible Diaphragms This section shall apply in SeISmic Zone 4 where flexible diaphragms, as defined in Section 208.5.6, provide lateral support for walls. I.
Elements of the wall anchorage system shall be designed for the forces specified in Section 208.7 where Rp ~ 3.0 and Q p ~ 1.5.
2.
In Seismic Zone 4, the value of Fp used for the design of the elements of the wall anchorage system shall not be less than 6.1 kN per lineal meter of wall substituted for E.
3.
See Section 206.4 for minimum design forces in other seismic zones.
4.
When clements of thc wall anchorage system are not loaded concentrically or are not perpendicular to the wall, the system shall be designed to resist all components of the forces induced by the eccentricity.
5.
" F+"F. , L., ,
---,'' ' --'' -'- w,,,, 2:" w; i",x
F"., determined from Equation (208-20) need not exceed! .OCr/wp.\"> but shall not be less than O.5CJwpJ:'
\Vhcn the diaphragm is required to transfer design seismic forces from the yertical~resisting clements above the diaphragm to olher vertical-resisting elements below the diaphragm due to offset in the placement of the elements or to changes in stiffness in the veliical elements, these forces shaH be added to those detennined from Equation (208-20).
3.
Design seismic forces for flexible diaphragms providing lateral supports for walls or frames of masonry or concrete shall be determined using Equation (208-20) based all the load determined in accordance with Section 208.5.2 using a R not exceeding 4.
4.
Diaphragms supporting concrete or masonry walls shaH have continuous ties or struts between diaphragm chords to distribute the anchorage forces specified in Section 20S.8.2.7. Added chords of subdiaphragms may be used to form subdiapluagms to transmit the anchorage forces to the main continuous crossties. The maximum length-to-width ratio of the wood structural sub-diaphragm shall be 2Y,: I.
5.
Where wood diaphragms are lIsed to latera!ly support concrete or masonry walls, the anchorage shall Zone 2 conform to Section 208.8.2.7. In Seismic and 4, anchorage shall not be accomplished by lise of toenails or nails subject to withdrawal, wood ledgers or framing sha!lnot be used in cross-grain bending or cross-grain tension, and the continuous ties required by item 4 shall be in addition to the diaphragm sheathing.
6.
Connections of diaphragms to the vertical elcments in structures in Seismic Zonc 4, having a plan irregularity of Type I, 2, 3 or 4 in Table 208- I0, shall be designed without considering either the one-third increase or the dun:tion of load illcrease considered in allowable stresses for elements resisting earthquake forces.
7.
In structures in Seismic Zone 4 having a plan irregularity or Typc 2 ill Table 20g~IO, diaphraglli chords and drat! Illcmbers shall be designed considering illdcp~'lldcnt movement or the projecting wings or tile structure. Each of these diaphragm
When pilasters are present in the waH, the anchorage
6.
The strength design forces for steel clements of the wall anchorage system shall be 1.4 times the forces otherwise required by this section.
7.
The strength design forces for wood elements of the wall anchorage system shall be 0.S5 times the force otherwise required by this section and these wood clements shall have a minimur" actual net thickness of63.5 mm.
208.8.2.7 Diaphragms !.
2.
The dcOcction in the plane of the diaphragm shall not exceed the permissible deflection of the attached clements. Permissible deflection shall be that deflection that wil! permit the attached clement to maintain its structural integrity uncleI' the individual loading and continue to support the prescribed loads. Floor and roof diaphragms shall be designed to resist
the forces determined following equation:
in
accordance
with
the
(208-20)
The force
force at the pilasters shall be calculated considering the additional load transferred from the wall panels to the pilasters. However, the minimum anchorage force at a floor or roof shall be that specified in Section 208.8.2.7. I, Item I.
2-99
National Structural Code of the PhilipPines bill Eclition Volume 1
~.100
CHAPTER 2 -. Minimum Design Loads
c lements shall be des ign ed for the mo re severe of the
following two assumptions: a.
Motion of the projec ting wings in the same direction.
b.
Motion of the projecting wi ngs
provisio ns contained in Section 208.9. 208.9.1.2 C riteria
The minimu m design seismic forces prescribed in th is
Exception: This reQl'irell!e!1! (TIllY•. ··be deemed..· satiifl.ed if. .-.the procedllr!2S of;§ec(ion 20R,'6 in cOlljullctio~ with a Ih reedimellsiQllpl . m.odel haye ..been IIsed to. de(ermine the lalera/ seismic forces for design. 208.8.2.8 F raming Below the Base The strength and stiffness of the framing between the base and Ihe foundation shall not be less than that o f the supers tructure. The special detailing requirements of Chapte r.; 4, 5 and 7, as appropriate, shall apply to columns supporting discont inu ous lateral-force-resisting clements and 10 SM RF, IMR F, EBF, STMF and
MMR WF system elements below the basel which are requ ired to transmit the forces resulting from lateral loads to the foundation.
I
specified in this section. Design shall conform to the applicable prov isions of other sections as modified by the
jn opposi ng
directions.
i
sha ll be designed to provide the s trength required [ 0 res ist [he displacements induced by the minimum lateral forces
208 .8.2.9 Building Sepa rations All structures shall be se parated from adjoining structures. Separations shall allow for the displacement t!",. Adjacent buildings on the same property sha ll be separated by at least 6 ,tfT where (208·21)
section a re a( a le"c1 that produces displacements in a fi xed base, clastic model of the s tructure, comparable to th ose expected of th e real stnl ctllre when responding to the Design Basis Ground Motion. Reductions in these forces using th e coefficient R is permitted where the design of nonbu ilding st ructures provides sufficient strength and ductility, consis tent with the provisions specified herein for buildings, [0 resi st the effec ts of seismic ground mo tions as rep resented by these design forces. When applicable, design strengths and other detailed design criteria shall be obtai ned from o ther sec tions or their referenced s tandards. The des ign of nonbuilding s tJUctures sha ll use the load combi nat ions or factor~ specified in Secti on 203.3 or 203.4. For nonbuildin g st ructures designed usi ng Secti on 20B.9.3 , 208.9.4 or 208.9. 5, the Re li ability/Red undancy Fac[or, p, ma y be taken as 1.0. When applicable design strengths and other design criteria are not con tained in o r referenced by this code, such criteria shall be obtained from approved national standards. 208.9.1.3 Weight W
and 6,1(1 and 6.m, arc the displ acemen ts of the adjacent buildings. When a structure adjo ins a property lin e nOI commo n to a public way, that structure shall a lso be set back from the property line by at least th e displacement tl" of that
The weight, W, for nonbuilding struct ures shall include all dead loads as defined for bui ld ings in Section 20B. S. I.1. For purposes of calcu lating design seismic rorces in nonbuilding struc tures, W shall also inc lude all nonnal operating contents for items such as tank s, vesse ls, bins and pipi ng.
structure. 208.9.1.4 Period
Exception:
"
".
Smaller separations or property line · seiback.i.::/~ay b.e permitted '.vlten justifieq .by ralia/ial 'i.ifci1ysej.·bi#ed Oil maxinllJnI
eXpected ground motions. :- .:~!.~-'
.
208.9. 1.5 Drift
208.9 Nonhuildi ng S tru ctu res 208.9.IGcncra l 208.9.1'. 1 Sco pe NOllbuilding st ru Ctu res include s truc tUl' c~
period or the structure shal l be determined by rational methods slIch as by using Method fl in Section 208.5.2.2. The fundamental
al l
sclf-
supportin g
other than buildings that ca rry gravity loads and res ist th e effects or earthq uakes. NOllb uildin g stru ctures
The drift limitations of Sec lion 208.5.10 need not appl y to nonbuilding struc tures. Drift limitations sh,!!1 lIe established for stnl ctural or no nstructural elenH~Il! '; ·':h.sc railure would cause life hazards. PA effects ;-.j;.,j! be co nsidered for s tructures whose calcula ted drills c:\cccd the values in Secti on 208 .5. 1.3.
Association of Struc tural Engineers of the Philippines
CHAP TEli 2··· Minimum
208.9.5 Other Nonbuilding Struclures Nonbuildi ng structures that are not covered by Secti ons 208.9.3 and 208.9.4 shall be designed to resist design seismic forces not less th an those determined in accordance with the provisions in Section 208. 5 with the foll owing additi ons and exceptions:
o· 208.9.2
I.
Laleral Fo rce
!{ateraJ-force procedures for Ilonbuilding stmctu fcs w ith 'structural syslems similar to buildings (those with ~·;tructural syslems which arc listed ill Table 208- 11) shall },e selecled in accordance with Ihe provisions of Section ".208.4.
:jjlllemJediote momeJJl-resisling frames (IMRF) may he (; ,used ill Seismic Zone 4 for non-building structures in ·". Occupall( V Calegories III alld IV if (1) Ihe slrllctllre is ~' less than J5 m in height and (2) rhe value R used ill .; reducing ca/clliated member forces and moments does 110/ ; exceed 2.8. ;: 208.9.3 Rigid Siructures
I
! :Rigid
structures (those with period T less than 0 .06 . 'second) and their anchorages shall be designed for the laleral force obtained from Eq uati on (208-22).
l
(208-22)
V ~ 1.6ZN .J W R ,
2.
r
(2 08-24)
The venical distribution of the design seismic forces in structures covered by this section may be dc(cml ined by us ing the provis ions of Section 208.5.5 or by usin g the procedures of Secti on 208.6.
Exception: For irfelW.lar s~ciures assigned ·' to Occupancy Categories r anq.fI that plinnPt b~ modeled as· a. Single mass, the procedures·oIS.dion 208.6·shall be used. 3.
The force V shal l be di stributed according to th e distributi on of mass and shall be assu med to ac t in any horizontal direc tion.
(208-23 )
Additionally, ror Seismic Zone 4, the lotal base shea r shall a lso no l be less than the following:
i
•
The factors Rand D. shall be as set fo rth in Table 208-13. The tolal design base shear determined in accordance with Seclion 208.5.2 shall not be less than the following:
V=O.5~/W
-f. ~.'Exceptiofl: if
r
2:··101
: In Seismic Zone 4, Slruclures thai support flex ible ; Jlonstnlctural clements whose comb ined we ight exceeds .25 percell I of the weight of the stnlct ure shall be designed
i:considering interaction effects between the structure and
i
Lor.ads
'. 08.9.1.6 InteracCion Effecls
: lhe supported elements .
!
O(~!->ign
Where an approved nationa l standard provides a basis for lhe c8I1hquake·resistant des ign of a particular ty pe of non bui lding st ructure covered by this section, such a standard Illay be used, su bject to the limi tati ons in this section:
208.9.4 Tanks wilh S upport ed Bottoms
t F
Flat bottom tanks or other tanks with supponcd bOtlOIllS, founded at or be low grade, shall be designed to resist th e i' seismic forces calculated using the procedures in Section 208.7 for rigid st11JClUreS considerin g the en tire we igh l of the tank and its contents. Altemative ly. sHch tanks may be designed using one of the two procedures described belo,w:
f
I.
2.
A res ponse spectrum ana lysis that includes con sideration of the acllla l ground Illotion anticipat ed at th e sile and th e inert ial cffects of the co nla incd nuid. A design b
The seismic zones and OCCUpl1llcy categories shall be in co nformance with the provisions of Sections 208.4.4 nnd 208.4.2,respecli ve ly. The va lues for total latera l . force and tOlal base overturn ing moment used in design shall not be less than 80 percent of {he values that wou ld be obta ined lIsing these provisions. 208.10 S ite Catego rization Procedure
208.10 . 1 Scope This sect ion desc ribes the procedure fo r dClcn nin ing Soil Profile Types S. , th rough S,.. as defi ned in Tab le 208-2.
th
Natiorli:1 1Structural Code of the Philipp ine s G Ecliti on Vo lurn(; 1
2- 1U2
CHAP TEr~
Table 208-13
2 _. Minimum Design Loads
3.
(H > 3 m of peat and/or higL:/ where H = thickness of so il ).
4.
Very high plasti city clays
R and flo Factors for Nonbuilding Stmctures
STRUCTURE TYPE
R
5. (11 > 7.5
I. Vesse ls, including tanks and
pressurized spheres, on braced or unbmccd legs. 2. Casl- i;l-pl acc cOllcrclc-silos ';;1(1 chimneys having walls con tinuo us to Ihe foundations
3. Dfsl~ibu lcd- ~11~ss ~~llIikv~;
-
2,2
2 .0
3.6
2.0
-- ----.
such as sl acks, chimneys, silos and skirtsupJ)ortcd vertical vessels. SllUctUfCS
2.0
Very thick sofVmedilllll stiff cI ,y.;
7.
(H > 36 '~l).
~ep!id~i; ,\, - .,; ..".'!i\:. la ' S
.
Jh.'!/f~t
~'J'1'~
'
.;/Ji rno.wni"·'~ _., ,e ,>,,:~'; ~'fee, ·TfPe SD slu.!! l i;;;~-~
·Tjlle ..~i d nol be' 'OSS""'2;! "t4eJer:inill~s .(hQI S¢.il P!" jii,' be pr.eSe'1ftii. the #fe or .i~ . Ihe evenl Ihat
b!iil
guyed), guyed stacks and
2.9
2.0
2.2
2.0
~
5. Caruilcvcrcd column -Iype
slnrClures. 6. Coo ling towers.
3.6
.- ':i.-· Bi~-s ';'~~j h~ppcrs 0;; b ~~~~~i ~;..
with PI > 75).
6.
irii,Qll iM's,q(('Pi:i!kt
2.9
4. Trussed to~~~ rs '(f~ccs-[a~ding or clljlll':t~Ys:
III
,''C:' "..
2.0
-. -
2.0
2.9
.. ,~!.~:~:.~c.~~_ I.cS_s ..
~
8. Stomgc rack s.
•... .. .....
3.6
-."
~
estabJishi!4 bjigeoJiCim;c'qj.!/Ibi4.·
The criteria set forth in the definition for Soil PfO filc Type
SF requiring site-specific evaluatio n s ha H be .... 01i:.. idered. If the si te corresponds to these cr iteria, Ihe s ite shall be classificd as Soil Profile Type S,' and " si te-specific evaluation shall be conducted.
2.0
208.10.2.1 v" Average Shear Wave Vol "cit)' 9. Signs and billboards.
3.6
2.0
10. Amu sement stru ctures and
Vs shall be detennined in accordance wit h the following equation:
(208-25) 208.10.2 Definitions Soil profile types are defined as follows:
s.. SR Sc
'·Iard rock with Illcasmcd shear wave veloc ity, I ' .• > 1500 IIl/s . Rock wi th 760 IIlls < I'. 5: 1500 IIl/s. Very den se soil and soft rock with
360 rnls < v.! :::; 760 ll1/s or with ei ther N > 50 o r s,, ;'
Ion kP a.
S"
S tiff soi l with 180 IIl/s'; v.,,; 360 IIlls o r wi th IS'; N,; 50 or 50 kPa ,; s,,'; 100 kPa .
St"
1\ so il profile wi th l's < J 80 Ill/S or any profile wit h more than 3 III o f soft c la y defined as soi l wi th PI > 20, W IIIo " ~ 40 perce nt an d x" < 25 kPa .
S,.·
~o il s
where: thi ckness of Layer i in m
til
=
V,n
= shear wave velocity in La yer i in
ntis
208.10.2.2 N, Average Field Standard Penetration Resistance and N tl" Average Standard Penefration Resistance for Co hesion less Soil Layer' N and Nell shall be determined in accord ance wi th tbe following eq uati on:
(208 -26)
requiring .:) it c~s pcc i(j c evaluation :
I.
Soi ls vulnerable to poten ti a l ra ilurc or co llapse under se is mic loading s lich as liqucliab lc so ils, quid nnd highly sensitive clays, co llaps ible wcnkly cClllcrHcd soils.
2.
Peals andlor highly organic clays
(208·2'.')
where: d,
=0
thickness of L.ayer i in mill
Ass ociation of Structural Engineers of tile Philippin es
CH;\PTE:H:? ·~
ds = thc total thickllc!is ofcohesiolllcss soillaycrs ill thc top 30 In N, :~ the standard pcnctralion resistance of soi l layer in
accordance with approved nationally recognized. standards 208.10 .2.3 s,,, Avera ge Undrained Shea r Strength SII
(208-28)
where:
Sus
Des~gn
Loads
2 ~103
and fracturing. Where hard rock conditions are known 10 be continuous to a depth of 30 m, surficial shear wave velocity measUJ emcnls may be extrapolated 10 assess V.I" The rock catego ries. Soi l Profile Types 5',{ Hnd Sfl. shall not be used if th<.°re is Illo rc than 3 meters of soil between the rock surface (did the bottom of' the sprcttd footi ng or mat rou ndat io n.
shall be determined in accordance wil h 1he fo llowing
equation:
de
MH1imulll
~
=
the total thickness (I OO-d,) of cohesive soil layers in the top 30 m the undrained shear strength in accordance with approved nationa ll y recognized standards, 110t to exceed 250 kPa
208.10.2.4 Soft Clay Profile , SE
The ex istcn ce ora lOla I thic kn css of sa lt clay greater than 3 III shall be in ves ti ga ted where a soft clay layer is defi ned by Sli < 24 kPa, 11'' ' ' '::: 40 percell ! and PI > 20. If these criteri a are met, the site shall be class ified as Soil
The definitions prese nted herein shall npply to the upper 30 meters orthe site profi le. Profiles co nt aini ng d isti nc tly differen t so il layers sllall be su bdivided into those la:if:rs designated by a number from I 10 11 at the bottom, whe re there are a tota l of 11 dist inct laye rs inl hc upper 30 meters. The symbol i the n refer to cillY one or the hlyers between I and 11. 208. 1 I Alt ern a ti ve E arthqu a ke Loa d P.-ocedur c The earthquake load proeedur" of ASCE/SE I 7-05 may be used in determin ing the carthquake loads as an alternative
procedure subject to re liable res(~a rch wo rk commissioned by the owner or the e n gi neer~oll ~ record to provide for all data req uired due to the non~avai l a b i l ity or Phi\'olcs~ iss ued spec tra l accelerati on maps for all areas in the Philip pines.
208.10.2 .5 So il Profil es So SD a nd S f
T he e ng ineer-on ~ reco rd shall be respo nsib le fo r the spect ral acce leration and oth er rcla! i.:d data not issued by Phivolcs used in the delerminatioJ: of the earthquake loads. This altemative earthquake 103.1 procedure shall be subject 10 Peer Review and approv~d of the Bu ild ing
Sites wi th Soil Profile T ypes Sc. So and Sf sha ll be
Orncial.
Profi le Type Sf.
classi fied by using one of the following three methods with l-:<; . Nand Sj' computed ill all cases a5 speci fied ill
Section 20X.1 0.2.
1.
I'~
2.
N Ii,,' the top 30 meters (N me thod).
3.
for the lOp 30 meters
(I'~
method).
Nm lor cohesionle," soil laye rs (PI < 20) in Ihe top III and average Sj/ for cohesi ve soi l layers ( .nl .> 20) ill the top 30 ill (.I'" meth od).
30
208.10.2.6 Roc k "rolil es, S ., and S/I
The shear W;lVC velocity for rock, Soil Profile Type 5fl , shull be eithcr Illc,lsurcd Oil site or estima ted by a gcotec hllical
eng inee r,
cnginee ring
gco logisl
or
scislllologist for cOlllpelellt rock wi th 11l0dCf<11c fracturi ng and wC~j(hcrjng . So fieI' and Illore high ly rractured and weathcred rock sha ll either he Illc;lsured on site for !-ihcar Wavc velocity or classilicd as Soil Profile Type Sc. The ha rd rock. Soil Profi le Type
S.,. category ,hail be
Supported by :>.hear wave ve locity measurcmen t cither 011 site o r ' on profiles or the S~lIllC rock typc in the salllc forma tion wit h tin equal or grea ter degree or weathcring N;·il innal Slruc!ural Code of Ole Pllil:ppines (jli' Edilion Volurnn 1
2-104
CHAPTER 2 - Minimum Design Loatls
Distribution
Active Faults and Trenches the/Phi ppines /
.
{J
~ ~()Ij
- - - Acttve Faull:
" 00'
Trench Transform FalA COlislon lOOO TrendHelat&d faUls Roadshlighw;J ys
e CitylTown
16'"
""
,, '"
1200'
' .00'
.'"
600'
127 00'
Figure 20S-2A. Seismic SO llrces: Active Faults and Trenches in the Philippines Associati on of SlruCluHl l Enginecl"s of tile Pllilippin es
200
CHAPTER 2 - Minimum Design Loads
ilO 00'
11100'
121 00'
122 00'
Active Faults in N
'"''
,
·t
"""
1600'
Logend _ _ _ Active Fault: solid line- onland : dashed line- offshore $ capital CltyfTown
I)
00'
140W
Figure 208-2B. Seismic Sources: Active Faults in Northern Philippines
~,
I
J
National Structural Cod e of the Philippines
6(h
Edition Volume 1
2-105
?~ 1 06
CHAPTEH 2 ·~ lViin illlwll Design toad~
., j
OG cl"
us 00'
I N 00'
l1HIO'
.,
Q.~
116 00'
East Central Philip p~n~ s Legend _
_
Active Faul!: solid hn:: ,-,[".i_.
I: •
. dashed line- otfshol c ® C
".,
-~
...
...
~
, - -- - --
1
i
i
II . )
b
;
'~
,I
i
L _ -."
_ __
J
_ __
11 to:!'
.
o
111')
Fi g ure 20X- 2C Scis mic Sources: /\(;Ii vc Fau lts in Ef1 s! Central Ph ilippi nes
CHAP TER 2 - Minimum Design Load s
"",
~.
, ,'
" "I:,; j
,
\~~~
1,", ,
t
I
!
I
:',
!
- /l0lY
I
Q
i{
:v <1
~~~
S." .leu
;:~, .. ,:'
't,
'
.
"
=
. ,"7' .'
6
.~.
o
.-P
.:\>
1100'
10 00'
\!O 00'
Figure 208-2D. Seismic Sources: Aclive F
L
111
Editi on Vo lume 1
2,107
2- 108
Cf~Af>TER 2 - Minimum Design Loads
''''
Legend - - _ Acttve Fault: solid lin e- onland ,
... ... dashed line- offshore @
Capital cltyrrown
&00"
IlJ 00'
Figure 208-2E. Seismic Sources: Active Faults in Southern Philippin es Association of Siructurul En9incers of the PhilipPin es
CHAPTER 2 - Minimum Design Loads
-------------------------------_._._-- -- -- -- - - Co nt ro l Periods 1~ =
CJ 2.SCa
= n?T
T
.1
c.
f f f
a
t
--J......------'-_ __ J _ _ ••••• _
••• ~ ""O""""'_ _ _ .L_____'__ ••••• I _. _ _ · _
o 0.2
I I
.L-._.L._ •• _ - ' - - - : ___ - ' _ _
5
4
3
2
.J..- .
Period (TITs )
TolTs
t
i
Figure 208-3 - Design Response Spectra Table 209- 1 - Soi l Lateral Load
Description Of Backfill Material ' Well-graded, clean gravels; grave l-sa nd mixes Poorl y graded clean gravels; gravel-sa nd mixes Si lly gravels, poorly graded gravel-sand mixes Clayey gravels, poorly graded grave l-and-clay mixes Well -graded , clea n sand s; gravelly sand mixes Poorl y graded clea n sa nds; sa nd-gravel mi xes Si lly sands, p oo rly graded sand-s ilt mixes Sand-si lt clay mix wi lh plastic fines --- Clayey sa nds, poor/ w aded sand-clay mixes Inorga nic sills and clayey sil ts Mixtu re of inorganic silt and cla y Inorgan ic clays of low to mediu m plasti city Organ ic silts and silt clays, low plasti ci ty Inorganic clayey sills, elaslic silts Inorga ni c clays of high plast icity Orga ni c clays and si lty clays
Unified Soil Classification GW GP GM GC SW SP SM SM- SC SC ML ML-CL CL OL MH CH
Design Lateral Soil Load' kPa per m width Acti ve pressure
At-rest pressure
5 5
10 10 10 10 10 10 10 16 16 16 16 16 Nole b NOle b Nole b NOleb
6
--
7 5 5 7 7
-
10
7 10 10 Note No te Note Note
0 1-1
b b b b
D esig ll Infernl .fOlI IOllds fin! .~i1'(·11 lfJr moi.rl COlldiliollS for lite spec!/ied sail.f til Ih eir opfimldl1 d elisi/it's. AOftnJ jh·/d ('(mr/lllolls shall gflll(!l·n. Suhmcrgcd or .W llrmf('d .\"oil IH ·t'.I'.flll ·".\" .I·froff inc/udt' Iht' wcighl of Ifl(' huoyllill Joil ,,11I.~ Ih" hydro.Hafie lo(/ds. I,
U I/.I'lIiloMe (I.I· ha("~fi /lm a(eri{//
'! he dc/illifioN (mri dO,l".\·i(ic(l l io ll oj".wi f moll'I'iuls shofl hI' ill (In'o rr/ollce lI"illl ASTM f) 2487
Nallon (-l l Stru c tural CO(j(~ of 11'18 PhlliPPI f"H:)S
r/' Edition Vo lun1e
1
2-109
2-110
CHAPTER 2 - Minimum Design Loads
1 tilr
1tfJ-'
....
•...
-
.
ZONE 4
••
ZONE 2
...
••
Figure 20RA Referenced Seismic Map of the Philippines
Association of Structural Engineers of the PhilipPines
CHAPTER 2 - Minimum Design Loads
2-111
209.1 General
210.1 RoofL1r;>inage
Basemenl , foundalion and re.aining walb' shall be designed to resist lateral soil loads. Soil loads speci fi ed in Tab le 209-1 shall be used as the minimum design lateral soil loads unless specified otherwise in a soil invest.igation report approved by .he building official. Basemenl ,valls
Roof dra inage -::ystclIls s hall be designed in accordance wi th th e provisio ns o f the code havi ng jurisdiction in the area. The flow C,1 j>:1 Clty of secondary (overflow) drains or scuppers shall no t be less than that of the primary drains or scuppers.
and other walls in which hori zon tal movement
is
restricted at Ihe top s hall be designed fo r at- reSI pressUi ,' . Retaining walls free to move and ro ••• e a. the lOp ar,; permitted to be design ed for active pressure. Design lateral pressure from surcharge loads shall be added to Ihe laleral earth pressure load. Design lateral pressure shall be increased if soils with expansion potential are present at the site.
210.2 Design Rain L, ads Each portion of a rot f shall be designed to sustain the
load of rainwater that \,\/i ll accumulate on it if the primary drainage syslem for t hat portion is blocked plus the unifonn load caused by water that ri ses above the inl et of Ihe secondary drainage " ystem at its design flow . (210-1) \\ ' ICre;
addiLional depth of water on the undeflcctcd
roof
(h,
:::
d
above the inlet of s(-condary drainage system at its design flow (i.e .. the hydraulic head), in mm = , t,'plh of water on the undefl ected roof up to the
in let of secondary drainage system when the prinary drainage sy,;rcm is blocked (Le., the stati c heac), in mm
R
=
rain I"c.·ad all the untie "lected roof, in kN/m2
When the phrcY) c "undeflcc: ~d roor' is used. deflections from loads (inclding dead I, ad s) shali not be co ns idered when dClcrmininh.' I.he amount ')( ra in on the roof. 210.3 Ponding lnst :l bility For roo fs wilh a slop,· less tiu n 6 nlln per 300 mm (I 19 degrees or 0.0208 rnd 'a n), the desig n calculati ons sha ll illclude verification 01" adcq ;late s tiffness to preclude progressive deflec tion in accc- rdance wilh Section 8.4 of ASCE-7-0S. 210.4 Co ntroll ed Drainage Roofs equ ipped with hard ,· ·a..e to control the rate of drainage shall be equi pped .y :th a secondary drainage
system at a higher clevation \:!l~\t limits accumulation of water 0 11 the roof above that c ',: .Iil li o n . Such roofs shall be designed to susta in the 10[;\ )[ rainwater that will HCCtllmlialc on them to the c ~V. Ilion of th e secondary dra in age system plus the uuife tll load ca used by W(lter thaI rises above th e in let or the sc:. ~(ndary drainage system at its design flow determined fre ',1' Section 210 .2. Such roofs shall al so bc checked for !.o nd in g instability in accordance with Section 2 10.3.
1h
National Structural Code of the Philippin es 6 Edition Volun1e 1
?'-112
CHAPTER 2 - Minimum Design Loads
first fl ood plain management code, ordi nance or standard,
"Existing construction" is also referred to as "ex isting structures. " 211.1 Ge neral
EXIST IN G
W ithin flood hazard areas as established ill Section 211 ,), all new construction of buildings, structures and port ions
construction."
of buildi ngs and structures, including su.bstantia l improvement and restoration of S4bl;(antial damage to buildings and structures, shall ' he designed and cons tructed to resist the efTects of flood hazards and flood loads. Fo r buildings that are locall' J in mOre than one flood hazard area, the provisions assvci ated with the most restrictive flood hazard area shall apply, 211.2 Definiti ons
The fo llowing words and term's SI13II, fo r the purposes of this section. have the mean ings show n herein. BA SE F L OOD , The fl ood having a I -pc rcent chance of be ing equaled or exceeded in any given year.
STR ucr UR E.
See
"Existing
FLOOD or FLOODl G , A general and temporary Or complete inundation of no rmally
condition of partial d,y land from : I.
The overflow of inland or tidal waters.
2.
The unusual and rapid accumulation or runoff of surface wa ters from any source.
FLOOD DAMAG E-RESISTA NT MATERIALS. Any construct ion material capab le of withstanding direct and
prolonged COrHacl with floodwaters without sustai ning any damage that requircs more th an cos metic repair. FLOOD HAZARD ARE A, T he greater of the fo ll o w ing
two areas: BASE FLOOR ELEVATION. The e levati on o f th e base fl ood, incl uding wave height, rel ati ve to th e datum to be
set by the speci fi c national or loc al govern me nt agr.:ncy. BAS E M E NT, The porti on o f " bu ildi ng havin.g its floor subgradc (below grou nd level) nn all sides, D ES IG N FLOO D. The flood associated w',th the greater of the following two areas:
I. 2.
Area with a flood plain subject tn a l·percent or greater c hance of flooding in any year; or Area designated as a nood haZc1.rd arca on a community 'S Oood hazud ma'i), or olhelwisc legally designated.
1.
The area within a fl ood plain subject to a I-percent or greater chance of fl oodin g ill any year.
2.
The area designa ted as a fl ood hazard area on a co mmu nity's flood haznrd map, or olhen-vise legally des ignated,
FLOOD HAZARD AR E A SU BJ ECT TO HIGH VELOCITYWAV E ACTION, Area within the flood hazard area that is subject to high velocity wave action. FLO ODWA y, The channel of the river, creek o r Olher watercourse and the adjaccnt Itllld arcas that must be reserved in order (0 discharge the base flood without
cumulatively increasing the water surface elevation more than a designated height.
D ES IGN FLOOD E LEVAT) ' J
. The e levation of the
"oesign Oood," includi ng W 3 ve heigh t, relative: to the datum specified on the co n ' nu ni ty's legally designated
LOWEST FLOOR. The fl oor of the lowest enclosed
area, including basement, but excluding any unfinished or
flood hazard map, The desif".1 fl ood elevation shall be the elevation of the highes t ex sting grade of the building's
flood -resistant
perimeter plus the depth J11 1,mber (in meters) speci ried on
parking, building access or limited storage provided that
the flood hazard map,
enclosure. lIsable solely
for vehicle
such enclosure is not built so as to render the structure in violation of this section.
DRY FLOO DP R O O F r\'G, A combinatioll of design
modifications that resll ;!s in a building or structure, including the attelldant u :·,I ity and sanitary faci lities, being water tight with walls ' mbstantially impermeable to the passage of water and v lith stru ctural components havi ng the capacity to resist h) ads .1S identified illlhc code.
ST A RT OF CONSTIWCfl ON , The diltc of permit issuance for new cOllslruclioll and substantial
improvemcnts to existing structures, provided the actual star! of construction, repair, rccC)nstlllction, rehab ilitatio n, addit ion, plilcement or ot her improvemen t is within 180 days afte r thc date of issuancc. The actual slllrt of
EXI STI NG C ONS" ,. RUCTlON , Any buildings and st ru ctures flH" \\"1 !ich the "s tart o f co nstructio n"
co nstru ction means the fi rst placement of perman ent co nstruction of a bui ldi ng (inc lud ing n manufactured
co mmcnced be fo rc the effective dat c of th e co mmunit y 'S
home) on a site, such as th e pou rin g of II slab or footings,
Association of Structura l Engineers of U·le Ph!lippines
CHAP TEH 2 ... Minimum Design l.oads .
i
installati on of pilings or construction of colurnmi. ,:" Pcrnnncnt construction docs not include land preparation ;. (slid, as clearing, excavation, grading or filling) , the It instaJlarion of streets or walkways, excavation for a f basement, footings. piers or foundations, the erection of :. temporary fonns or the installation of accessory buildings K such as garages or sheds not occupied as dwelling units or ~ not parl of the main building. For a substantial n improvement, the actual "start of construction" means the r. first alteration of any wa ll, ceiling, floor or other t· structura l parl of a building, whether or not that alteration , affects the externa l dimensions of the building.
t
, SUBSTANTIAL DAMAGE. Damage of any origin t sustained by a structure whereby the cost of restoring the i structure to its before-damaged condition wou ld equal or exceed 50 percent of the market value of the structure before the damage occurred. SUBSTANTIAL IMPROVEMENT. Any repair, reconstruction, rehabilitation, addition or improvement of a building or stru cturc, the cost of which equals or exceeds 50 percent of the market value of the structure before the improvement or repair is started. If th~: structure has sustained substantial damage, any repairs arc considered substantial improvement regardless of the actual repair wo rk performed. The term does not, however, include either: 1.
Any project for improvement of a building required to correct existing health, san ita ry or safety code viol ations identified by the bui ld ing official and th at. are the min imum necessary 10 assure safe liv ing condi ti ons,
2. Any alteration of a historic sll11cture provided thai the alteration wi ll nOt preclude the structure's contin ued designation as a historic stru cture.
2-113
211.5 Flood Hazard Documentation The following documentation shall be prepared and sealed by an engi neer-of-record and submitted to the bui lding official : I.
For construction in flood hazard areas not subject to shigh~velocjty
wave action:
1.1. The elevation of the lowest floor, inc luding the basement, as required by the lowest floor elevatio n. 1.2. for fully enclosed areas below the design flood elevation where provisions to allow for the automatic entry and exit of floodwaters do not meet the minimuTJ) requi rements) construction documen ts shall include a statement that the design will provide for eq ualization of hydrostatic flood forces. 1.3. For dry flood-proofed nonresidential bui ldings, construction docu ments shaH include a statement that the dry flood -proofing is designed . 2.
For construction in flood hazard areas subject to high-velocity wave action:
2. I. The elevation of the bottom of th e lowest horizontal stmctural member as required by th e lowest floor elevation.
2.2 Constmction documen ts shall include a statement that the building is designed, including that the pile or column foundation and building or structure to be attached thereto is designed to be anchored to resist flotati on, collapse and latera l movement due to th e effccts of wind and Oood loads ac ti ng si mul tan eously on all building components, and other load requirements of Chapter 2. 2.3 For breakaway wa lls designed 10 resist a nominal load of less than 0.48 kN /m 2. or more th an 0.96 kN /ml, construction documents shall include i;l statement Ihm the breakaway wall is designed .
211.3 Establishment of F lood Hazard Areas To establish flood hazard areas, the governing body shall adopt a flood hazard map and supporting data. The flood hazard map shall include, at a minimum, areas of special flood hazard where records are available.
211.4 Design and Construction The des ign and construction of bui ld ings and structures located in flood hazard areas, inc luding flood hazard a rCHS Subject 10 high ve locity wave actioll.
th
National Structural Corle of tile Philippines 6 Edition Volurnc 1
Associat ion of StrlJcluml EngIneers of the Philippines
NSCP C101-10
Chapter 3 EXCAVATIONS AND GEOMATERIALS NATIONAL STRUCTURAL CODE OF THE PHILIPPINES VOLUME I BUILDINGS, TOWERS AND OTHER VERTICAL STRUCTURES SIXTH EDITION
Association ()f Structural Enginccrs of thc Suite 713, Future Point Plaza Condominium 1 112 Panay Avenue, Quezon City, Philippines 1100 Tel. No : (+632) 410-0483 Fax No.: (+632) 411-8606
Email: i\;-i~P9}}EJ1~{~~gmniL£QL1~. \V chsi tt': ht f p:iIww\'~' .ascponlinc.org
Philippincs
CHAPTER 3 - Gen eral & Excavalion and Fills
3· 1
Table of Contents
t
!f tt I
SECTION 3()1 • GENERAL ...................................... ............................................................................................................... 3 301. I Scope ......... ..... ................................................................................. ......... .......................... ..................... ...................... 3 301.2 Qualily and Design ....... ......... ..................... .. .................................... ...... ................. ..... .. ... ....... ........ .... ..... .................... 3 30 1.3 All owable Bearing Pressures ..... ..................................... ... .... .. .. ........ ........ .... ................... ................ .. ....... ... ... ............. . 3 SECTION 302 - EXCAVATION AND FILLS ........................................................................................................................ 3 302. I General ........................................ .... ... ......................... ....... .. ................................ ............................. ... ...... ..... ... ... ........ 3 302.2 Cuts .. .......................................... ......... ..... .......... ..... ..... ........... .... ................................. ...... ......... ......... ........................ 3 302.3 Excava ti ons .. .......... .. ... ..................................... .. .... .......... .. ....... .... ............................. .... .. ... ..... ............. ...................... .. 3 302.4 Fills ......................... .......................... .... ................. ......... ...... ............... .. ....... .. ..... ... ............ ...... ... .... ........................ .. .... 4 302.5 Selbacks ........................................ .................... ..... .............. .............. ... ... ....... ..... ................ .......................................... 5 302.5 Drainage and Terraci ng ... ..................................................................... ...... .. ................................................................. 6 302.6 Erosion Contro!. ...... ................. ............... ..................................... ... ....... .......................................................... .............. 6 SECTION 303 - FOUNDATION INVESTIGATION ............................................................................................................ 7 303. I General .......................... ...... ........................................ .... .............................................................................................. 7 303.2 Soil Classification .......................................................................... ..................................................................... ............ 7 303.3 Questionable Soil .................... .. ................ ............ ...... ................................. .. ....................... ........................ ........ ......... 7 303.4 Liquefaclion Sludy ...... ................................... .......................... .. .. .............. ............. .. ....................... ............ ....... ......... 7 303.5 Expansive Soil .. ............ ...... ...... .................... .. ........................... ................ ... ........................................ ... .................. 7 303.6 Compressible Soils ............................................................................ ........................................................................ 8 303.7 RepOrts.... ....................... ............................. ... .. .. ..... ................................... .. ....................................... ........ 8 303.8 Soil Tesls .................. ........ . ...... ....................... .......... ....................... . ................................. .. ...... ....................... ... 9 303.9 Liquefaction Potenlial and Soil Sirength Loss.................... ................................. ............................. .. .. 9 303 .10 Adjacenl Loads.................. .......................................... ................ .. ......................... .. ............ ........................ 10 303 .11 Drain.ge........................................... ....... .. .... ...... ....... ........................................ ........ .... ... ........... ....... ............... 10 303. 12 Plate Load Test ................................... .. ............ .. ........ .................................................... ................ .... .. ....... .... ....... 10 SECTION 304 - ALLOWABLE FOUNDATION AND LA TERAL PRESSURES ......................................................... 10 304. 1 From Geotechnical Site Investigation and As sl~ss m e n( ...... ,........... ....... ............. ............... .. ................. ... .. .......... 10 304.2 Pres umplive Load·Bearing and Lateral Resisting Values ........ .. ......................... ....... ....... .......... ...... ........... JO 304.3 Mininlunl Allowable Pressures... .............. .... .................. . .. ....... .. _........ ...... . ,....... .. ........... ... .... .... ....... I J 304.4 Fou ndmi ons Adjace nt to Exisl ing Retainin g/Basement Walls..
,...... ,............ ... .................. ......... J 1
SECTION 305 · FOOTINGS .......................................... ........................................... .................................... ......................... 12 305. 1 General ................................................................................................... ................................................................... 12 305.2 FOOling Design .... .... ....................................................... ............... ................. .... ........... ....... .................................... 12 305.3 Bearin g Walls ................. .......................................................................... .................................................... .............. 12 305.4 S lepped Foundalions .. .............................................. ............................................................. .......... ............... .............. 12 305.5 Footi ngs on or Adjacenllo Slopes............................................................... .. .......................................................... J3 305.6 Foundalion PI ales Or Sills ........... ....... ....................................... .......... ...................... ....... ......... .. ................ ................ 13 305.7 Designs Emp loyi ng Lateral Bearin g .................................. .. .............. ..... .... ........... ....... ................ ... .... .............. ..... ..... 14 305. 8 Grillage Footi ngs .................. ......... .. .................................................... ...... ......................... .. ............................ ......... 14 305.9 Bleac her Fooli ngs .. .... .. .... .. ............. .. ..... ... ... .................. .............................................. ... ... .......... ... ...... .. ... ..... .............. 14 SECTION 306 · PILES - GENERAL REQUIREM E NTS ................................................................................................... IS 306. I General .......... ............................. ......... ................... ...... ................ ...... .. ....... .................................... ......................... .. .. 15 306.2 Interco nnection ............................................. "... .... ........................ .................... .......... ,... ., ........ .. ........... ...... .. ......... 15 306.3 DClernlinalion o f Allo\vablc Loads ............... .......................................... ................................ ....... ................ ...... ....... 15 306.4 Stalic Load Test...... .. ........................ ... ............................................................................................................ 15 306.5 Dynamic Load Tes l...................................................................... ............... .. ..................................................... 15 306.6 COhl1111l Act ion .................. ................ ........................... ................... ............................... .. ... 15 306.7 Group ACl io n .................... ............................. ................ ........... ............... ....... ....................... 15 306.8 Pi les In S ubs id ing Areas.... ................ .... .......... .. ............................... 16 306.9 Jellin g .................................... ................... .................... .. .. 16
306. 10 Pro lc<.:lion Of Pile Materials ........................ ..... ... .. 16 306. 1 I Allowable Loads.......... .......... ................. .................. . ................ ....................... ..... 16 306. I 2 Usc of Hi gber Allowable Pile Stresses ............ .... .. .. ........ . ............... .. .. 16 SECTION 307 . PILES - SPECIFIC REQUiREMENTS ....................................... ............................................................. 17 National Structural COdE: of the Philippines 6
lh
Edition Volum e 1
307.1 Round Wood Piles. 307.2 Uncased Cast-In-Place Concrete Piles .. 307.3 Metal-Cased Concrete Piles .. 307.4 Precast C:oncretc Piles .............................................................................................. ...... . .. 307.) Precast Prestressed Concrete Piles (Pretensioncd) .. 10 , ') 307.6 Structural Steel Piles .. 307.7 Coocrete·Filied Steel Pipe P i l e s . . )
SECTION 308 . FOUNDATION CONSTl!UCTlON·SEISMIC ZONE 4 ........................................................ " . ........... 19 308.1 General.. ~08.2 Foundation and ()eotcchnicallnvestigations . 3tnLl Footings and Foundations .. 308.4 Pier and Pile Foundations. 30X.) Driven Pile Foundations.. 306.6 Cast-In-Place Concrete Foundations..
()
/0 ;i . ..................... .
SECTION 309 - SPECIAL FOUNDATION, SLOPE STABlLIZA TION AND MATERIALS OF CO NSTl! UCTI 0 N .................................... .............................................................................................................................. 22
,
CHAPTER 3 - Gelleral & Excavation and Fills
3-3
I 30J.! Scope This chapter sels forth requircmems for exclwarions, fill s, footings and foundations for any building Or structure.
302.1 General Excavation or fills for buildings o r structures shall be constructed or protected such that they do not endanger life or property. Reference is made to Section 109 of this code
301.2 Quality and Design
for requiremenls governi ng cxcavalion. grading and earthwork construc tio n. including fills and e mban kments.
The quali ty and desig n of materi als used strucltlfally :ii excavalions, fills. footings and foundations sh all conform to
the requirements specified in Chapters 4, 5, 6 and 7.
302.2 Cuts
301.3 Allowable Bearing Pressures
302.2.1 General
AJlowable stresses and design formul as provided in this chaplcr sha ll be lIsed with the allowable stress design load
Unless otherwise reco mmended in the approved geotechnical e ngineering. c uts shall confonn (0 the provisions of this section . In the absence of an approved geotechnical engineering report . these provisions may be waived fo r minor cuts not intended to support structures.
combimuions specified in Section 203.4 .
302.2.2Slol'e The slope of cut surfaces shall be no steeper than is safe for the intended use and shall be no steeper than 1 unit vertical
in 2 unit s horizont al (50% slope) unless a geotechni cal engineeri ng, or both, staling that the site has been investigated, and giving an opinion that a cut at a steeper slope will be stable and not create a hazard to pub lic or private property, is submitted and approved. Such cuts shall be protected against erosion or degradation by sufficient cover, drain age, engineering andlor bi otechnical means.
302.3 Excava tions 302.3.3 Existi ng footin gs or foundations which may be affected by any exc ava ti on shall be underpinned adequately or otherwise protected agai nst se ttl ement and shall be protected against lateral movemen t.
302.3.4 Protection of Adjoining Property The requirement for protection of adjacent property and the depth 10 which protection is required shall be defined by preva iling law. Where not defined by law. the foHo wing
shall apply;
th
National Structural Cod e of tlie Philippines 6 Edition Vo lume 1
3 -4
CHAP TER 3 - General & Excavation and Fills
Top of Slope
PA*
: 1-115 but
~ ~ 0.60 m3
: min. an .r . -, I 3 In max .. 7'
Toe of
PA*
Sl~pe
~ < HI2 bJ!! 0.6 m,> : : mi n. and 6 m
,
C ut or Fill Slope
, I
i
-I ~ IIII S I Natura\ 1or FGrade
:
H
max.
1 * Permit Area Boundary
Figure 302·1
1.
Natural or Finish Grade
Setback Dimensions for Cut and Fill Slopes
Before commencing the excavation, the p e~on making
or causing Ihe excavation to be made shall nOlify in writing the owners of adjoining building not less than 10 d ays before such excavation is to be made and Ihal
302.4. 1 General
the adjoining building will be protected. The condition of the adjoining building will be documented to include
geotec hnical engi neering report, fills shall confonn to th e
photographs prior to excavation. Technical docume nts pe nallllng to the proposed underpinnin g and excavation plan shall be provided the owner of the adjacent property. 2.
302.4 Fills
Unless it can shown th rough a det ai led geotechnical
in vestigation that underpinning is unnecessary. any person making or causing an exca.vation shal l protect the excavati on so that the soil of adj oining property will not cave in or settle,
In cases where the existing adjacellt building will have morc bascmcllls tha n the proposed bui ld ing. Ihe foundati on of lhe proposed building should be designed so ;IS not 10
impart add itional lateral eanh pressures on the existing build ing (sec scc ti on 304.4).
Unless
mherwise
recommended
in
the
approved
provisions o f th is sectio n. In the absence o f an approved geotechn ical e ngineering report, these provis io ns may be waived for minor fills not intended 10 support st ruc tures. Fills to be used to suppon the foundalions of any building or struClUre shall be placed in accordance with accepted engineering prac rice. A geotcchnical invcstigation ' report and a report o f satisfactory placement of fill. both acce ptable to the building offi cial. shall be submitted when required by the building official.
No (ill or other surcharge loads shall be placed adjacent to any bu ilding or slmClUrc unl ess such building or stru ctu re is capable of wi thstanding the additional vertic
As sociation of Structura l Engineers of the Philippines
CHAPTER 3 - General & Excavation and FillS
Preparation of Ground ground surface shall be prepared to received fill by vegetation, non-complying fill, top soil and other nSl,iW:ble materials by scarifying and benc hing in the case
,__ " "inO
sloping ground The existing ground surface shall be prepared (0 receive fill by rem oving vegetation
~d,:qu"e,y
materials, non-complying fill , lopso il and other Im:,uiltable materials. a nd by scarifying LO provide a bond Ihe new fill.
3-5
be used based on ASTM D5030 -04. A minimum o[ three tests for every 500 m2 area should be performed for every lift [Q ve rify compliance with compac tion requirements. 302.4.5 Slope The slope of fill surfaces shall be no Sleeper 'han is safe [or the inlended usc. Fi II slopes shall be no stceper than I unit vertical in 2 units horizontal (50% slope) unless subs tantiat ing slope stabili ty analyses justifying steeper slopes arc submiucd and approved.
the natura! slopes arc steeper than I unit venienl in 5
' units horizontal (20% slope) and lhe height is greater than · 1.5 m, the ground surfucc shall be prepared by betlch ing into sound bedrock or other co mpeten t . mated al as determined by the geotechnical engineer. TIle bench under the loe of a filion a slope sleeper than I unit venical in 5 unils horizon,.,1 (20% s lope) shall be OlleaSI 3 m wide.
I i
i
The area beyond the loe of fill shall be sloped to drain or a paved drain shall be provided_ When fill is to be placed over a cut, the bench under the toe of fill shall be at least 3 III wide but the cut shall be made before placing the fill and onJy after acccpt.mce by the geotechnical engi neer as a suitable found ation for fill . 302.4.3 Fill Material Any organic or deleterious ma terial shall be removed and
Ii
will not be permitted in fills_ Except as pennined by the geoteChnical engineer, no rock or similar irreduc ible material with a maximum dimension greater than 200 mill shall be buried or placed in [ills.
ftxception:
I I
~~e placemem of larger rock may be permitted when
Ihe geotechnical engineer properly devises a method of placement. alld contitlf(ollsly inspects its placemellf alld approves lire fill stability_ The following conditions shall
also apply: 1_
Prior to issuance of the gradinB permit, pOlential rock disposal areas shall be delineated on the grading plan.
2.
Rock sizes greater Ihon 300 111m in maximwn dimension shall be 3 m or more below grade, measured vC!'(ically_
f
3.
Rocks shall be placed so w· 10 assure filling of all voids wilh well-grotled soil.
302.4.4 Co mpa ction
All rill s shall bc co mpac ted in lifts Ilot exceedi ng 200 Illlll ill th ickncss 10 II min imuill of" CJ5 percent of maximum density as determined by ASTM Standard D- I 557. Inplace dcns it y shall be determincd in .\ccordancc with ASTM D-1556. D-2Ifl? 1)·2922. D-lO I? or eq ui va len t.
302.5 Setbacks 302.5.1 GClIcral Cut and fiJI slopes shall be set back from si te boundaries in accordance with this sect ion subjec t to verification with delailed slope stability study. Selback dimensions shall be horizontal distances measured perpendicular to the site boundary. Setback dimensions shall be as shown in Figure 302-1. 302.5.2 Top of C UI Slope The top of cut s lopes shall not be made nearer [0 a s ile boundary line than one fifth of thc vertical height of cut with a minimum of 0.6 III and a maximum of 3 m . Th( sctback may need to be increased for any required interceptor drains. 302.5.3 Toe of Fill Slope The toe of fi 11 slope shall be made not nearer to tbe site boundary line than one half the height of the slope with ~, minimu11l of 0.6 In and a maximum of 6 m. Where a ft:: slope is to be located near the s ite boundary and Ih, adjacent off-site propcl1y is developed , special precaution: shall be incorporated in the work as the building offici:.:.! deems necessary to protect the adjoining propel1y fro !: damage as a re su lt of" such grading. These precautions m
Additional setbacks.
2_ Provisio n for retaining or slough walls. 3.
Mechanical s tabilizati o n or chemical lreulmen( of I~ ;: fill slope surface to minimize eros ion.
4.
Rockfall protection
5_
Provis ions Cor the contro l of surface wate rs.
302.5.4 Modification of Slope Location The hui lding offici'll may approve allc lllatc sctback s. Ti· buildin g offici al l1lay requ ire an investigation ' ~! ' . rccollllllcn
For clean granular mah.:/"ials. thc lise of the foreg oing procedures is i n;'l pproprialc. Rcl,Hi vc dcnsi lY critc ri a shall 111
N;·l!IOI·l~li Slnl c tlHcll Code of !he Phi lippine s 6 Editi on Volume 1
3-6
CHAPTER 3 -- General & Excavalion and Fills
Exception:
302.5 Drainage and Terracing
The gradient from Ihe bllildillg pad may be I perccm fr all of the following conditions exisl Ihroughout fli £.' per;;:;1
302.5.1 General Unless o therwise indicated
011
the approved grading plan,
area:
drainage facilities and terracing shall conform to the provisions of this section for cut Or fill slopes Sleeper than I unit vertical ill 3 units horizontal (33.3% slope).
1.
No proposedji fls ore greater thall 3 m maximum depth.
2.
No proposed finish cut or fill slope f(lces have a vertical height in excess of 3 m.
302.5.2 Terrace
3.
No existing slope faces steeper than 1 IInit verlh.",,: in 10 units horizontal (10% slope) hGlle a vertical hc,iglll ill excess of 3 m.
Terraces ill !CHst 2 III in width sha ll be estti bl ished at nOI more than 10 III ve nical intervals o n all ellt o r fill slopes to contro l sUlface drainage and debris except Lhal where on ly o ne lerracc is required, it s hall be al mid-height. For cuI or fill slopes greater than 20 III and up to 40 111 in vertical height, one terrace at approximately mid-height shall be 4 m in width . Ten'ace widths an d spacing for cut and fill s lopes greater than 40 m in height shall be designed by the civil engineer and approved by the buildi ng official. Suitable access shall be provided to permit proper cleaning and maintcnance. Swales Qr ditches on terraces shall bc designed 10 effectively co ll ect surface water and di sc harge to an outfall. It shall have a minimum gradient of 0.5 percent and must be paved with reinforced concrete not less than 75 mm in thickness or an approved equal paving material.
A si ngle ru n of swale or ditch s hall not coll ect runoff from a tri but
302.5.3 Subsurface Drainage Cut and fill slopes shall be provided with surface drainage as necessary for stability.
302.5.4 Disposal All drainage facilities shall be designed to ca rry waters to the nearest prac ti cable drainage way approved by the building official or ollIer appropriate jurisdiction as a safe place to deposit such waters. Eros ion of gro und in the area of discharge shall be prevented by installation of n on ~ erosive down drains or other devices or splash blocks ,mei sed iment ation bas in s.
302.5.5 Interceptor Drains Paved or Lined interceptor drains shall be in stalled alo ng the top of all cut slopes where the tributary drainage area above slopes toward the cut has a drainage path greater than 12 m measured horizontally. Interceptor drains shall be paved with a minimum of 75 mm of concrete or gu nile and re info rced. They sh:lIl have a m in imum depth of 300 mOl ilnd a minimum paved width of 750 mm measured horizontally across the drain. The slope o f drain shall be approved by the building offic ial.
302.6 Erosion Conlrol 302.6.1 Slopes The faces of c ul and fill s lopes shall be prepared and maintained to con trol ngainst erosio n. Thi s conLrol m3Y consist of effecti ve planting adapted to or indigenous (Q the loca lity. The protection for the slopes shall be installed as soo n as practicable and prior to calling for final approval. Where cut slopes arc not subjec t to erosion due to the erosion-resistant character of the material s, sllch protection may be omillcd .
302.6.2 Othel- Devices Where necessary, check dams, cribbing, Iiprnp or other devices or method s shall be employed to control erosion and provide safety.
Building pads s hall have a drtlinage gradien t of 2 percent toward approved dminage facilities, uoles!'; waived by the huilding official .
/\ssociation of Structural Engu'le(;I'S of the PllilipPIl'18S
CHAPT ER 3 - General & Excavalion and FillS
3-7
Addit ional studies may be necessary to evaluate soil strength, the effect of moisture variation on soil-bearing capacity, compressibilit y, liquefaction and expansiveness. 303.1 General
303.3 Questionable Soil
Foundation in vest igation shall he conducted and a professiollal Repor! by a Regis(ered Civi l Engineer experienced or knowledgeable in Soil Mechanics and Foundations shall be submitted at each building site.
Where the classification, strength or compressibility of the soil are ill doubt, or where a load bearing va lue superior to that specified in thi s code is claimed, the building official shall require that the necessary soil investigation be made.
For structures to two stories or hi gher" it is recommended th at an exhaus ti ve geotech ni cal study be pcrfonncd 10 evaluate in-situ soi l parameters for foundation design and analys is. II is recolllmended that a minimum of one
303.4 Liquefaclion Study The bu ilding official may requi re a Liquefaction evaluation stud y in accorda nce with Secti on 303.6 when. during the cou rse of the roundati on investigation, all of the following conditions are discovered:
borehole per two hundred, 200 11\2 of the slruclUrc's
footprint be drilled to a depth of at least 5 III into hard strata or until a suitable bearing layer is reached unless otherwise specified by th e consu lting geotechnic al e ngi nee r. The total number of boreholes per structure shou ld be no less than 2 for stJUcturcs whose footprints arc less than 300 m2 and no less (h an 3 for those sl mcturcs wi th larger footprints. For buildings with basements, it is recommend ed that the depth of boring should ex tend to twice the least plan dimension of th e structure ' s footpri nt plus the depth of the
I.
Shallow ground waler. 2 m or less.
2.
Unconsolidated saturated sa ndy alluvium (N < 15)
3.
Se ismic Zone 4.
1:.,~\:cep t ioll:
The building offiCial may waive this evaluation upon receipt afwritten opinion of a qualified geotechnical engineer that liquefaction is not probable.
basement. 303.5 Expansive Soil An exhaustive geotech nical invcstig.ltion should also be conducted in Ci.lSCS of questionable soils, expilnsive so ils, unknown groundwater table to determi ne whether the exist ing ground wale!" table is above Of" within 1.5 m be lo w the elevation of the lowest 0001' level or whe re such floor is located below the finished ground level adjacent to th e foundation, pil e foundations, or in rock stra ta where the roc k is sllspected to be of doubtful characteristics or indicmc variati ons in the structure of" th e rock or wlwrc solution cavities or vo ids are expected to be prcse nt in the rock. The building official lIlay req uire that the interpretation and eval uation of the resu lts of the foundation invcstigation be made by a regis tcred civil engineer experienced and knowledgeable in th e field of geotechn ica l cnginccring.
Soils meeting all four of the following provisions shall be considered expansive. except that tests to show com pl iance with Items I, 2 a nd 3 shall not be required if the test presc ribed in hem 4 is conducted: !.
Plasticity index (PI) of 15 or greater, determined in acco rdance with ASTM D 4318.and Liquid Limi t > 50.
2.
More than 10 percent of the soil particles pass a No. 200 sieve (75 111), determined in accordance with ASTM D 422.
3.
Marc than 10 percent of the soil parti cles arc less than 5 micrometers in sile, determined in accordan ce with ASTM [) 422.
4.
Ex pansion index grea ter than 20, determined in accordance with ASTM D 4829.
303.2 Soil Classific:t lion
303_5.1 Design fol' Expansive Soils
For Ihe pu rposes of this cha pte r) the defin iti oll ;1I1d class iri c:lli on of soi l materia ls for use in Table 304-1 sha ll
Foo tin gs or foundati ons fo r buildings and strucLUres fo unded 0 11 expansi ve soils shall 1:-•• designed in accordance wi th Section 1805.8.1 or 1805.8.2.
be accord ing to I\STM D-2487. Soi l classifi cat ion shall. be based on observat ion
Foo tin g or foundati on desig n nced not compl y wit h Section
303.5.3 or 303.5.4 where the so il is rcmoved in accordance with Sect ion 303.5.4, nor where the building offi cial approves stabilization of the soil ill accordance with Section 301.5.5.
NotlOll al S ll"l!(:tural Code·) of tile
I
Pl1ilippll"les G" Edition Volume 1
3-8
CHAPTER 3 - General & Excavalion and Fills
303.5.2 Foundations Footings or foundatio ns placed o n or wit hin the active zone of expansive soils shall be designed to res ist differenti al vo lume chnnges and to prevent st l1Jctural damage to the
suppoJ1cd structure. Defl ec ti on and rac king of the supported shall be limited to that which will not interfere wi th the usabil ity and serviceability of the structure. Found ati ons placed below where vo lume change occurs or below expansive soil shall com ply with the following provisions: I.
2.
Fou ndat ions ex tending into or pe netrating expa nsive soils shall be designed to prevent uplift of the supported structure. Foundations penetrating expansive soils shall be designed (Q res ist forces exerted on the fou ndation due to soi l volume changes or shall be isolated from Ihe expansive soil.
303.5.3 Slab on G round Foundations Momen ts, shears and deflections for use in designing slab· on·ground mat or raft foundations on expa nsive soils shall be determin ed in accordance with WRIICRSI Design of S!ab·on-Ground Found~ti on s or PTJ Standard Requ irements fo r Analys is of Shallow Concre te Foundations on Ex pansive Soils. Using the moments, shea rs and deflecti ons detemu ned above, prestressed slabs· on·groun d, mat or raft foundations on expansive soils sha ll be designed in accordance wi th PTJ Standard Requ irements fo r Design of Shalfow Post·Tensioned Concrete Foundat ions on Expansive Soils. It shall be permitted to analyze and des ign such slabs by other methods tilat account for soil·s truclu re interaction, the defo rmed shape of th e soil support, the place or s tiffened plme action of the slab as well as both cemer lift and edge lift conditions. Such alt ernative methods sha ll be ra tional and the basis fo r all aspects and param ete rs of the method shall be ava ilab le for peer rev iew.
303.5.4 Removal of Expa nsive Soil Where expansive soil is removed in lieu of designing footings or foundations in accordance wilh Secti on 302.3.2, the soil shall be removed 10 a de pth sufficient to ensure a constant moist ure contenL in Ihe rema;ning soil. FiJI material shall not cont ain ex pansive soils <1 11<1 shall comply with Section 302.3.3.
303.5.5 Stabiliza ti on Where the active zone of expansive soi l ~ is stabi li zed in lieu of designing footi ngs or fou ndations in accord
303.7 Reports The soi l classification and design bearing capacity shall be shown 0 11 the plans, unless the fou ndation co nforms to Tab le 305-1. The build ing official ma y require submission of a written repon of th e investigation , whi ch shall include, but need not be limited to, the followin g informati on: I.
A plOl showing the locat ion of all test borings and/or excava ti ons.
2.
Desc riptions and classifi cati ons of the materia ls encountered.
3.
Elevation of the waler table, if encountered.
4.
Recommendations for foundation Iype and design criteria, including bcuri ng capacity, provisions to mitigate the effects of diffcrential scttlements and ex pansive soils, provisions to mitigate the effects of liquefaction and soi l strc ngth , provisions for spec ial fo undation solutio ns and ground improvement, and the effec ts of adjaccnt loads.
5.
Expected total and differentia! settlement.
6.
Laboratory test resu lt s or soil sam ples.
7.
Field borehole informat ion a) b) c)
d) c)
Exception: Expansive soil need not be removed 10 the depth of constant moisture, provided the confining pressure in the expallsive soil created by the fill and supported s/ruClllre exceeds the swell pressure.
lug
co nta ining
the
following
Project locmioll Deplh of borehole Ground elevation Grollnd water t;tblc c!cv.atio!1 Date !'tarled and finished
T he soil ciassific.ltion and dcs ign·beari ng capacity shall bc shown on the pla ns, un lc:-s the foundat ion con forms to
Tab le 305- 1.
Associatio n of Structural Engineers of tile
Pt1i li ppine~~
CHAPTr: R 3 - General & Excavation and Fills
When expansi ve soils are present, the bui lding official may
Table 303·3 Geophysical Tests
require thai speci,ll provisions be made in Ihe roundati on
design and constmction to safeguard against damage due to this expansiveness. The building official may require a special in vestigati on and report to provide these design and construction criteria. Table 303-2 Laboratory and Field Tests
Laboratory I Field Test
Output OatH I I ASTMJ Test I Parameter Obtained nCS i 1!Il ~lfioJ1
Field Test
ASTM Designation
D2216-05
Grain size analysis Atterberg Li mits
D422-63 D4318-05
uses
D2487-00
Specific Gravity Shrinkage Limit Organic Matter
D854-05 D427-04 D2974-00
Swedis h Weight Sounding Test
115 A 1221:2002
Moisturel Waler con lent Soil grad ation Liq uid limit, plasti c Ii mi t Classificati on of soils Specific gravity Shri nka~e limit Moisture content, ash conteiH and percent orl!a nic mutter in soi l N~w-value indicating, undrain ed so il shear strength
UCT Test (Soi ls) Tri-ax ial (UU Test) Tri-axial (CU Test) Oedollleter ( I -D Consolidation) Laboratory Va ne Shear Direct Shear Test UCT for Intact Rock Standard Penetration Tes t Modified Proctor Test Standard Proc'{or
D2166-00 D2850-03a
Strength parameters Strength parameters
D4767-04
Strength parameters
D2435-04 D4648-05
Consoli dation parameters Strengt ll parameters
1)3080-04
Strength pa ram cters
D2938-95
Strength parameters
Geophysical Tests
Seismic reflection
D5777-00
Ground Penetrating Radar
D7128
Cross hol e seismic survey
D6432-99
Geo-resisti vity Survey
D4428
Maps su bsurface geologic conditions, lithologic unit s and fractures. Maps lateral continuity of lithologic units and detects changes in the acoustic properties of subsurface geomatcrials. p-wave and !i-Wave velocity determination. elastic modul i . detcllllination CO!Tosion Potential or so ils, Electrical grounding, slratigraEhic stlldie~ _
303.8 Soil Tes ts Tables 301-2 and 103 -3 summarize the commonly used fi eld and labora to ry tests needed in determining the in-situ so il parameters for use in foundati on design and analysis. 303.9 Liquefaction Poten tial and Soil Strength Loss When required by Section 3(H.3. the poten ti al for soil
liqucfaction and soi l strength loss during eal1hquakes shall be cvaluated during the geotechnical investigation. The
D1586-99
N- va lue
D IS57-02
Max imum dry densit l' tvlaximulll dry
D698-00"
Test
Field Density Test Cil R t,,1> Test Cone Penclnltion
Output Data I Parameter Obtained
Seismic refract ion
Classification oj .soils Moisture content
:;-9
de nsi ty I)
IS56·00
D ISH3-05 1)3441-05
Maximull1 dry density CIl R
Soil strength
~~~ ___,________,_._..._. ______J.~~~~~.!::.~ _.. _._. ____ ._
geotech nical evalua ti on shall assess potenti,11 liqueractio n susceptib ility potentia! t:onsequc nccs of any liquefaction ;l!ld soil stre ngth loss, including estimation of differential se ttl ement. lat cr;i1 movement or reduction in fo undation ='t1i l-hcill'i ng cap;lcit y.
s pceilicd in SCd ioll 20K.fl.1. Peak grollnd Cleeclerillion m:": hJ;lllond i S !!Ucl lJ !,ll COd (; 0 1 Ii 1(-: PI1I IIPi J1 :k:'; ((
hl:\IO!l \J()llllill'~ 1
3-10
CHAPTEri 3 --. General & Excavation and Fills
be determined based on a site-specific study taking into account soil amplifkation effects. In the absence of such a study, peak ground acceleration may be assumed equal to the seismic zone factor in Table 208-3.
303.10 Adjacent Loads Where footings are placed at varying elevations, the effect of adjacent loads shall be included in tile foundation design. 303.11 Drainage Provisions shall be made for the control and drainage of surface water around buildings and ensure that scour will not threaten sllch structures through adequate embedment. (Sec also Section 305.5.5). 303.12 Plate Load Test The plate load test is generally used for determination of soil subgrade properties for rigid foundations. If used for building foundations, it mllst be emphasized that the Depth of fnlluence is only up to twice the width of the test plate. Care must be used when extending the results to deeper depths.
304.1 From Geotechnical Site Investigation and Assessment The recolllmended allowable foundation ;in,! 1;,1' '.,; pressures slwtl be estimated from a rcasonahi y (" . geotechnical site investigation and assessment, which shall include at least the (o!lowing:
a)
Description or regional geologic
b)
Characterization of in-situ geotechnical conditions;
c)
Factual report on the in··situ and lahora!or), :c ~;i:: performed to characterize the site rSc'.,' .\,'clinn 303.7 for a list of ill-situ and lal.1;;i<::\):Y IC:;I~ commonly carried out for geotechnical site characterization) ;
d)
Disclosure of the assumptions and tllc :,-ppliclbk. analytical or empirical models used in the allowable foundation and lateral pre:," ii \:'.;
e)
Calculations carried out and Factor til' ;! assumed in arriving at the recommended :.llluw,il.:J(' foundation and lateral pressures; and
f)
Evaluation of existing potential ge(.llogic haZ;\Fds and those that may be induced or triggered by the construction/installation of the structure.
eh;!r;l,;[~' i'isiic:;;
The geotechnical site investigation and assessment shall be performed by a registered civil engineer experienced and knowledgeable in the field of geotechnical engincering. A geotechnical investigation and assessment shall !)c presented in a repoli. The repoli, together with a brief resume and a sworn statement of accountability or ' I Je geotechnical engineering consultant who prepilred :i, ·11 be included in the submittals to be reviewed ,-Ull! C'\dl i · '. :d by the building official or government authority in ch:\r,:,~,e of issuing the relevant permits stich as ellvirol1:n( ':al compliance cel1ificatc and/or building permit. 304.2 Presumptive Loacr·Bearing and Lateral Hesisting Values
When no exhaustive geotechnical site assessment and investigation is perrormed, especially when no in-silu or very limited tests arc carried out, the preSUJ11pl;\",~ k.;:dbearing and lateral resisting values provided in 'j',lbk ~W I shall be uscd. Usc of these v;lIues requires Ihal Ihe. foundation design engineer has, at the least, clnicd oul iii] inspection of the site and has hecollle familiar with tile predominant soiJ or rock characteristics or the site. Association of Structul"al Lnqincc:rs of the
Philipplne~;
C HAPT E ~~
.,,
.,
Presumptive JO:l
!
For clay, sandy day, si lty clay and cla yey silt, in no case shaJllhc latera l slid ing resistance eKceed one-half the dead load.
3 -- Gene ral & Excav ation and F:llls
3- 11
304.3 Minimum Allowable Press ures. The recommended all owable foundali on and lateral values shall be with the allow ab le stress design load co mbin ations specifi ed in Secti on 203.4.
, 304.4 Fo undations Adjacenf to Exis ting Relainin g/Basemcnt "" all.1i
In cases where the adjacent building will have more basemcnls th an (he prob'oscd bu ilding, lhe foundation of the proposed build ing shqukl be designed so as not to impal1 addi ti ollallatcrnl earth pressu res on th e existing building.
It is (he responsibililY of lhe engineer-DC-record 10 determine the applicability of these presLi mptive values for Lhe Project. Table 304-1 Allowable Foundation lind Lmcrai Pressure
!
Class of Materials l
!
i
Latera l Gearing
Allowable Foundation Pressure!
I1 clow Nftl ura l
( kJ'a )
(kPaJm of
Lateral Sliding'
-----
l
Grade·
Coeffici cntS
deplh)
Rcsistance6
(kPa)
f
!
L Mass.i ve Crystalline Bedrock
200
200
0.70
2. Sedimentary and Foli ated Rock
100
60
0.35
3. Sand y Grave l and /or Grave l(GW & GP)
100
30
0.35
4. Well -graded Sand. Poorly-graded Sa nd. Silty Sand. Clayey Sand. Silty Gravel and Clayey Gra ve l (SW. SP, SM. SC, GM and GC)
75
25
0.25
5. el.y, Sandy Clay. S ilt y Clay and Clayey Silt (CL. ML. MI-I, and CH)
50'1
15
!
II
,
7
J
A geotechnical sire' illl'c.Higmiol! i.~ /'{' c(IIwneIJdl'dfor .wil r/os.\'ifi('(/li(1/I (Rljl'!' /0 S('rlioll JO.l). Afll/a/IlCS of alloll'able /oU/u/(lIirm p res.que (lI~' [ul'j()(n ill.t:..f hm'illl; fllllillillll/l11 wit/ill (If .loa //I1I/1I11t! (} millimum d<'I)(11 (~r JOO mill info I/lI' .wfllml gl'(ldc. Except as li med in I-nomOft! '(I ' , all iI/crease 0120% i.f o/foll'ed for I'm'" lIa(liliOlWI 300m", of \I'lfllil (1I/(lItlt'til'I'th III t/ II/t/xill/mll l 'O/lIt' ojthrei' lilli,'.,' Iilr desigl1l1/C'(/ \'(Ilile. All inr:rCII,ft! oj f1/1t!-,hird i.f {wl'lIIil/('(/ ....·h('11 IIsin.': III!' (llt('n/tlft' lam/ nllllbhrll/iol/:r ill S.'rliOIf 103,4 111m illf/m/t· 1";/1/1 o r earthquake loads. The resi.'iflltl('e 1'(I l l1eS deril'cd from 'he labie {1m IU!111Ii(l('tl /(J br il/t'I'c'f1Sl't/ by rhe /II /JII lnr I'n/lle for /'uch mlt/irilllw l .100 111m oj (/t'll/ll IrJ (I 111/1.1'/1111111/ of 15 limes th e lahular !lallle. I .w/med po/e.( fo /' u.w:s .fllch asj/ag{lIIll's fir .fig ll .\· (//1(/ {Ioks 1I.I'('d 10 supJlo rt IlIIiJdill}i .~ Ihlll (11'(' no{ ad" f'l'wty (((fi'I 'ln! hy (/ 12 111111 lliOlio!! af 11/(' groul1d .mrfacl' rill{' /I! .~/1fIrt·f('rlll t(l tem! Irwds 111'1' p(, l'miw'd III IU' dt'.\·igl/t't! II sing Itll cro/· /ic((rillg ('(IIIICS equal 10 111'0 1;II!('s Ifll' I(Ilm /1ll l'
/.alent! hctll'lIIR (1 11(/ f/idil/.~ ,,(·.~i.H(lIIn' "'11\· 1)(> I·olllhitu·d.
C(Jeg;/'iI'1JI {() hI' lilli/lip/iN/ hy
/11('
ch'l1(J ',,~/(t.
I.ul/~I'(" didillg rC.f if{m/{'I' " (IIUt' to I,C' lIIulti/,lil'rl Ily 111(' OJ/llm'l orl'(/ . III
III)
nul' .(Iml/ IIII' /(111'1'(1/ .I/hlmg
1'f'••·i.#{/1WI'
No iIlI'rC'fI.W' .fllalf /1(' a llowed/or OIl i llr ·/'('a.w' (~r wid fh .
N;)llollal S lrllcl llr~:ll Code of lilt;; PhlllPPill OS (,'
:.dltlon \lOlll l: 1f~
/'l'/ '/'('(I (J//(" ./m{f IIii' (ka t! Ir~/fl.
3"12
CHAPTER 3 - General & Excavalion and Fills
305.2.1 Design Loads Footings shall be designeofor the most unfavo rable load effec'ts duc' to combi nations of loads_ T he dead load i s pennitted to include the weight of foundations, (ooti ngfi and overlying fill. Reduced live loads as penni tlcd in the Chapter o n Loadings are perm itt ed to be used in th e design of foot in gs.
305. 1 General Foo lings and foundations shall be constructed of ma so nry, concrete or treated wood in conforman ce with Chap ters 4,
6 and 7. roolings of concrete and masonry shall be of :wli d materiaL Foundations supporti ng wood sha ll extend at least 150 mill above the adjacent finish grade. Footin gs s hall have a minimum depth as indicated in Table 305 ~ I, unless another depth is warranted, as eSUIblished by a
305.2.2 Vibratory Loads Where machinery operations or other vibratory loads or vib rati ons are transmitted to the foundations, co nsiderat ion shall be g iven in the repon to address the founda tion design to prevent detrimental disturbances to the soil due to vibratory loadings .
foundation investigation. The provisions of Ih is section do not apply to bui ld ing and foundation systems in those areas subject to scou r and water pressure by w ind and wave acti on. Buildings and
found
Dynamic Soil Properties shall be inc luded where requi red .
such loads shall be designed in
to
305.3 Bearing Walls
accordance with approved nati ona l standards. Table 305·1 Minimum Requi rements fo r Foundations T hick ness of
NlI llIhcr of
Floors Foundation Wall S upported (0101) .. by the -~;ii-Foundations CtHlcretc Masonrv
--_ _-150
of
of
Undis tu rbed
Fooling
FOOlin g
Gro und
150
.... .... 2
200
.. _. 200
J
250
250
_
-
, Wlt",-(, 1111I1 ~jW{
(111m)
(mm )
300
150
.. _. '
"" -
f·lIIlth'fllll.{ IUC
foulld_
Surface (111111 ) 4
300
.
375
175
450
450
200
600
fimllll.t:J:
1"I'{1II;"1'11 11/ SI', 'li(1/I 305. 1, Tilt' ~rrm/l(!IfIll!l' r ,hi' fllNlr flllly IN' I'.IH/wtln! {II'
Depth Belo w
Width ~'hickncss
--
I
1.2.J
.-
Bearing walls shall be SUppo!1cd on masonry or rc info rced concrcte fou ndat io ns o r pil es or other permitted foundati on system Ihal shall be of suffic ient size to suppOt1 all loads. Where a design is not pro vided, the min im um foundation requirements for stud be arin g walls shaH be as set forth in Table 305~1, unless expansive soils of a seve rity to calise differential move ment are known to ex ist.
i:.xcepl ions: I.
A o ne~story \Vood or metal{rame building 1101 used 2 for human occupancy alld 1I()l over 40 m if! floo r a rea may be cOllstructed witll walls supported all a wood foundarion plale permallelllly Illlder lile waler wble when permitled by the buildillg official.
2,
nit! support of buildings by /lOsts embedded ill eartli shall be designed as specified ill Section 305.7. Wood posts or poles embedded ill earth shall be pressure treated with an approved preservative, Steel posts or poles shall be protected as specified ill Seclioll
mlll/rmmltllmi/J J'hnlf
fl .\
/(I
Ihl' cll' l'(l/jml
0ll{lf'
If/I' IIJI'I~frHlIIlIg. I FIH/I/Ilmillll
111((,\-
.\up/Hn'l
(I
TtIO[ ill mldi/;o/I UI 1111' 51i,1ll1r1l1'11 !"IIlmlll'" rfHifl' only .f/wlllJl" (1.1 rl'i/llir(!11 jf/r
"f jloorJ. . FllwU/fII;mlS _1//PfHlrlin.s: IIIPI'"nillg tJII(' jloor_ Till' (ir/JlII "11',,,/)(,,/111('/1/
IIIIIM (l1\\,(lr.1
111' bl'l,,1I' flO/l'll/iul 11.('/""
11/
.ff 11/11-
305.2 Fnoling Design
306.10.
Except for special provisions of Section 307 coveri ng the dc .. igl1 uf' piles. all p0l1io!ls of footing s .. hall he designed in m:cord;lllcc with the :-tl11clUml provisions of thi s ernie and :-hall he designed to.:illinimi7_c diffcrellli ;'ll ... cttlcmcnt whcn nc('cssary ;Intl thl" effects of expansive soils whl"1l prc.<:;cnt .
305 .4 Slepped !'oundalions Foundations for all buildings where the surface of the ground slope.... morc than I lInil VCl1ica l in I (J units horizolllal ( 10% .'dope) shall hc level or shall he s(eppcd so (hal both top and bouom of such foundation arc level.
Siah-on-gradc and mat type f( XHings I'll!' huildings Ilx-med cxransivc soils may he dcsigncd in act.:orclilllCC with 1he gl"tHcch nil'ltl reco llllllcndation as pCl'Illitled hy tile "wildin g official. 011
/\SSOCi;ltl(lll c)f S tnI C!U( "1 1 Enqu1f:c: rs of (h(~ Pililippilw:;
CHAPTER 3 -- General & Excavation and Fills
Top of Slope
Face O(SII1lClurC Hn but need not exceed
,7'
l
4.5m m..'tx.
3-1 3
~:
Of.5,'_IO_.P" /I
H/3 but neoo nOi cxccC!d 12 III malt.
,r'
I
- - - --"---
Figure 305-1 Setback Dim('llsions for Ouilding Clearance from Slopes
305.5 Foolings on or Adjacent 10 Slopes 305.5.1 Scope The place ment of buildings and strucltJres on or adjacent to slopes steeper than I unit vertical in 3 units horizontal (33.3% slope) shall be ill accordance with this section.
305.5.4 Pools The set back between pools regul ated by thi s code and slopes shall be equal <0 one half ,he building footing setback di stance required by this section. Thm portion o f the pool wall within a horizontal di stan ce of 2 III from the top of (he slope shall bc c,lpablc of snpportin g the waler in the pool without soil SUppOI1.
305.5.2 Building Clearance from Ascending Slopes
In general, buildings below slopes shall be set a suffi cient distance from the slope to provide protection f~om slope drainage . Scour erosion and shallow failures . Except as provided for in Seclian 305 .5.6 and Figure 305-1. 'he following crit eria will be assumed to provide thi s protection. Where the ex isting slope is steeper than I uni t venical in I unit horizont al (100% slope), the loe of the slope shall be assumed 10 be at the intersection of a JlOrizontal plane drawn from the top of the fou ndmion and a plane drawn {angen! to the slope at an angle of 45 degrees (0 the horizontal. Whe~e n retainin g wall is constructed at the toe of [he slope, the height of the slope shaH be measured from the top of the wall to thc top of 'he slope. 305.5.3 Fooling Selback from Descendi ng Slol)e Surface
Footings on or adjacen t to slope su rfaces shall be founded in finn m
305.5.5 Fou ndation Elevation On graded sites, the top of any exterior foundation stwll extend above the elevation of the street guuer at point of discharge or the inlet of an approved drainage de vice a mininlUlli of 300 mill plus 2 percent . The bui lding official may permit alternate elevati ons. provided it ca n be demonstrated that requ ired drainitge Itl the point of discharge and away from th e ~ tm c tllrc is provided at all loc:uions on the site. 305 .5_6 Alternate Setback and Clearance
The building o ffici al Ilwy approve uhcrlliHe selbacks ilnd clearances. The building offici al lllay require an in ves tigation and reco mlllendmiol1 of a qualified engineer to demonslrate that the intent of this section has been inves tigati on shall incl ud e satisfied. Such an con1;ideralion of material , heigh! of slope, slope grildicnl, load intensi ty and erosion chafllc lerislics of slope material . 305.6 Foundation Plates or Sills Wood plates or sills shall be boIled 10 the foundation or foundation wall. Sleel bolls with a minim ulll lI ominal diameter of 12 I11Ill shall be lI sed in Scismic Zonc 2. Steel ho lts with a minimum nomina l diameter of 16 mill shall be lIscd in Seismi c Zone 4. Bolts shall he cmbeddcd at least 180 mm in to the COllcr C(L' or lllilSOIlrY ilnd sh.JlI Ill' spaced not morc than 2 III apart. There. shall be a minimum of two bolls per piece wi th (inc bolt inc
N,ll tOn<;lJ ~;!ruclu r<-Ij Code of the Pllil ippHw s G ' Edilioll Volume 1 ti
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CHAPTEli3 -- General & Excavation cllld Fills
more than :WO mm or Jess than seven bolt diameters from of the piece. A properl y sized nut :111(\ washer shall be liglll cncd 0 11 each boIL to Ihe plate_ Foundati on "hlles an d sills shall be the kind or wood specified in Chapter 6. c~c h e nd
305.7 Designs Employing L·atcraJ Hearing 305.7.1 General Constructio n employing posts or poles as columlls eillbedded ill e:lrth or embedded in concrete fOOlings in the earth m;IY be used and designed (() res ist both axia l and 1~ll c ntl loads. Th e depth to resis t latera l loads shall be determined by means of the design edteri,l eswb lished he rein or other IllclllOds ;lpp roved by the build ing official .
305.7.2 DeSign C"il eria
305.7.2.1 NOll-cons train ed The follo wi ng formula ma y be u !'l~ d in delermi ning the depth or embedment required 10 resist latc ral loads where no constrailll is provided at Ihe gro und surface, sllch as rigid floor or ri gid grouJld surface pn\ l' m Cnl.
d= 2II
( f ----) 1+
4.3/i 1+ - - 11
(305·1 )
h
d II
P S,
.,'1
The resistance to vertical loads is dCl crmi ",cil I,.: allowable soiJ·bcaring pressure sct forth ill T:!! : _. ," :
~: i C
305.7.3 Backfill The backfill in the annular space around column not em bedded in poured footings shall be by one of the following methods: 1.
Backfill shall be of concrete with an UJtiIlHi l.;. s! !"r nglh of ! 5 MPa at 28 days. The hole shall not lw ks': IiLH l 100 mill large r (h an the diameter of the Cf\ IUlIln :~ t ils bottom
or
100 mm
larger
than
dimensi on of a Squ fU"C or rectan gu lar
2.
~h t:
,: .. .. O Ili:!
coi u !lII'.
Backfill shall be of clean sand . The sand shall be thoroughly co mpac ted by tampin g in la yers not morc than 200 I11I1l in thickness.
305.7.4 Limitations The design procedure OlH li llCd in thi s section shall be subject to the fo ll owing limitations: 305.7.4.1 The fri ctional resistance for retaining w(\;L'; and slabs Oil silts lind clays shall be limited to one half ur {he normal force impo~ed on the soil by the weight of the footing or slab.
'0
305.7.4.1 Posts embedded in eanh shall no. be used provide latera l suppOrt for siructural or nOllslruclural maleri als such as pl aster, masonry or concrete un less bracing is provided.
where: A
305.7.2.3 Vertical load
2.3 P
S,"
= uia me ter of rollnd post or foo ting or diilgonill d i lll~n sio n nf squa re post or foo tin g. III = depth of emhedment in (~art h in 111 btl l 1101 ove r 3.5 III for p"q')ose of com pIlling lateral pressure. III = d ist:1I1CC from ground surface 10 poilU of applic;ltion of P, m = applied lateral force. kN = allow:!blc late ral soil-bearing pressure as set forth in T,lblc 304- 1 based on a depth of one third the depth of embedment, kPa = allowabl e latc ral soil-bcclring press ure as set forth ill Tahle ~04- 1 hased O il it depth equal to the depth o r cmhedmCIll. kPa
305.8 Gril lage Footings When grillage footings of Sll1lclura l steel shapes
305.9 Bleacher Footings Footings for open -air seating facilities sh;l!1 comply with Chap.er 3. ExceptiOlIS: Temporary open -t,;r porlllble bleacher.'i may be JUPI)(l! : :·d IIpon wood ,'iil/s or .\'I(~el plates placed directly UpOIi the .r: mull •...J surface. prm-idetf soil pl"l'.\·sure doC's /l of ('x: I'(~d
J05.7.2.2 COllsll'a in cd
50kPa.
The following fnrllwlil llIi1y hI..' u:ie(1 [0 del cnninc the depth of emhedment requ ired to rc."is l 1;l1(,l'ill loads where constrain t i ~ provi ded :tI Ihe ground surface, such as iI rigid floor or pave mcnt.
005·2)
CHAPTEFi 3 - General & Excavation and Fills
3·1 b
306.4 Static Load Test Static axial compressive pile load tcst shan be in accordance with ASTM Standard 0-1143. Performance of the load test require that lhe test be conducted under the supervision of a registered civil ellgineer experienced and knowledgeable in the practice of static pile !oad testing.
be designed and installed on the of a foundation investigation as defined in Section where required by the building official. The investigation and rCpO!1 provisions of Section 303 shall be expanded to include, but not be limited to, the
. following:
Recommended pile types and installed capacities.
When the a!lowable axial compressive load of a single pile is determined by a static load test, one of the following methods shall be used: Method 1. It shaH not exceed 50 percent of the yield point under test load. The yield point shall be defined as that point at which an increase in load produces a disproportionate increase in settlement.
Driving criteria. Installation procedures. Field inspection and reponing procedures (to include procedures for verification of the installed bearing capacity where required). Pile load test requirements. The use of piles not specifically mentioned in this chapter shall be permitted, subject to the approval of the building official upon submission of acceptable test data, calculations or other information relating to the proper1ies and load-carrying capacities of such piles. 306.2 Interconnection Individual pile caps and caissons of every structure subjected to seismic forces shall be interconnected by tic Beams. Such tic beams shall be capable of resisting, in tension or compression, a minimum horizontal force equal to 10 percent of the largest column vertical load.
Exception: Other approved methods mav be used 'where it can be demonstrated that equivalent ~es(raint can be provided. 306.3 Determination of Allowable Loads
The allowable axial and lateral loads on piles shall be determined by an approved formula, by a foundation investigation or by load tests. Static axial compressive pile load test shall be in accordance with ASTM Standard D-1143, and lateral load testing or piles shall conform to ASTM Standard D-3966. Dynamic pile tcsls shall be in accordance with ASTM Standard D-4945. Static axial tensile load testing to determine [he uplift capacity of pile-soil systems shall be in accordance with ASTM Standard 1)·36X9.
Method 2. It shall not exceed one half of the load, which causes a net settlement, after deducting rebound, of 0.03mm/kN of test load, which has been applied for a period of at least 24 hours. Method 3. It shall not exceed one half of that load under which, during a 40-hour period of continuous load application, no additional settlement takes place. 306.5 Dynamic Load Test
High-strain dynamic load test may be used to determine the bearing capacity of piles, in accordance with ASTM Standard 1)-4945. It is required that the test be conducted by a registered civil engineer experienced and knowledgeable in the practice of pile dynamic load testing. 306.6 Column Action All piles standing unbraced in air, water or material not capable of lateral support shall conform to the applicable column formula as specified in this code. Such piles driven into finn ground Illay be considered fixed and laterally supported at 1.5 III b,elow the ground surface and in son material at 3 III from the ground surface unless otherwise prescribed by the building official after a foundation investigation by an approved agency. 306.7 Group Action
Consideration shaH be given to the reduction of allowable pile load when piles are placed in groups. Where soil conditions make such load reductions advisable or necessary, the a!lowable axial and lateral loads determined for a single pile shall bc reduced by any rational method or formula submitted to the building official.
hlalloll,'li Structure.'!i Codo of the PhiiippinE)s 6: Edition Volunl(~ 1 1
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CHAJ'TF.:f1
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,.. Genera! & Excavation and Pills
306.8 Piles in Subsiding Areas Where piles are dri ve n through subs iding fill s or other
i ;
306.12 Use of Higher Allowable Pile Stresses Allowable compressive stresses greater than those wh" '-' ~
s ubsiding Siratil .1Ild dClive suppon from underlying
specified in Section 307 s hall
firmer materials, consideralion shall be given (0 the downward frictional forces, which may be imposed on Ihe piles by Ihe subsiding upper st raw which :-;Ilall be deductive fromlhc nel pile 10
substantiating data justifying such higher stresses are submitted to and approved by the building official. Such substant iating data shall be included in the foundation in vcslig;:nion repon in accordance wilh Section 306, 1.
Where (he influence of su bsiding fill s is conside red as imposing loads on the pilc, Ihe allowable si resses specified in this chapter may be increased if sati sfactory substantiating data arc su bmiucd ,
306.9 Jelling In stallmion of pilcs hy wal eI' jelling shall nol be uscd excepl wherc .lI1d as spccifically permi{lcd by {he building official. When uscd, jetting shall be carried oul in slich a manner Ihm tile carrying capacity of existing piles and sl l1icturcs shall not be impaired, After withdrawal of the jet , piles shall be dri ve n down untillhc required res istance is obtained ,
306.10 Protection of rile Mntcriais Where th e boring records of sile conditions indicate possible delet eriolls action on pilc Ilullerials becau se of soil cOllstilllc nls. changing wCllcr lc\fC ls or olher fact ors, such materi als shall be i.ulequatel y protected by methods or processes approved by Ihe gcotech nical engincer. The effectivcness or sllch methods or proccsses for Ihe particular purpose shall have been thoroughly established
by sm i,SfaclOry service reco rds or other evide nce, which dClllonst r;lh;-s the effectiveness of sud I protective measures,
In su lfate hearing soi ls. the stee l piles shall be prolectcd agains! corrosioll or reinforced <..'O l1c['Clc piles shall usc Typc rr ccment. 306.11 Allowable Loads The allowable loads based on soil conditions shall be establ ished in accordance wilh Sect ion 306. Exception: Ally ulIca,\'ed casl- iJ/ ~place pile may be assIlIIu1d 10 d l!\'C'ilJ!' a Fiefiollol l'C'sisf(/l1 ce i'qual 10 (Jill! ,n"xlh (?{ Ihe bea r;IIK I'(t/II(' of tile' :wif maferial (11111;11 111111111 de/JIb nf ,\'('1 forth in Table' 305 -1 l)fa lIot to exceed 25 kPa III rlt'.I",\" a ~U '('(I/('r I'a/ue i ,\' allowed by till' Imildill/o: official (!{ter (I foundation illl'esliga lio/i as sp ecm ed ill .,'eclioll 303 is slIhlllilled" Frictional r('siS(W1C e (/1/(/ hearillg rcsi,l'lal/ce shall lIot he a,\'slIlIwd (0 tlct sil1lulllllU'OIiX/Y {(I/{('ss rl!('ol1lllu'lI(/ed (iffer a jrmlldatirm illVl'sliMaliOI1 as
s{J('{4ied ill
S('c'liOIl
3fJ3,
be pelmilted
CHAPTER 3 - General & Excavalion and Fills
3- 17
307.3 Me(al-Cased Concrete Piles 307.3.1 Ma(erial Concrete used in metal-cased concrete piles shall have a specified compressive st rength of nOI less than l7 MP•.
i'e
307.1 Round Wood Piles 307.1.1 Ma(erial '>'.
Except where ulltre:ncd piles arc permitted, wood piles shall be pressure treated. Untreated piles may be used only when it has been establ ished that the cutoff will be below lowes t groundwater level assumed to exist during
307.3.2 Installation Every metal casing for a concrete pile shall have a scaled tip with a diameter of not less than 200 mm .
[he life ortlle sll1lc lurc.
Concrete piles cast in place in metal shells shall have shells driven for their full length in contact with the surrounding soil and left permanenlly in place. The shells shaH be sufficiently strong to resis t collapse and sufficiently watertight to exclude waler and foreign material during the placing of concrete.
307.1.2 Allowable Stresses The allowable unit stresses for round woodpiles shall nOt exceed those set forth in Chapter 6 .
The allowable va lues listed in. for compression parallel 10 the grain III extreme fiber in bending are based on load sharing as OCClII'S in a pile cluster. for piles which
support their own specific load, a safety factor of 1.25 shall be applied to compression pluallel to the grain values (md 1.30 to extreme fiber in bending values. 307.2 UncHsed
Cast~In~Place
Piles shall be driven in such order and with such spacing as to ensure against distortion of or injury to piles already in place. No pile shall be driven within four and one~haJf average pile diameters of a pile filled with concrete k:-;s than 24 hours old unless approved by the geotechnic;,~J engineer.
Concrete Piles
307.2.1 Ma(erial
Concrete piles cast in place against earth in drilled or bored holes shall be made in such a manner as to ensure the exclusion of any foreign matter and to secure a sized shafi .
rull~
The drilled or cxcav
307.3.3 Allowable Stresses Allowable stresses shall not exceed the values specified :i; Section 307.2.2, except that the allowable concrek s[r ( ~· may be increased to a maximum value of 0.401'" fo r that portion of the pile meeting the following co nditions : I.
The thickness of the meta! casing is not less thall 1.7 mill (No. 14 carbon sheet steel gage);
2.
The casing is seamless or is provided with seams c· eq ual strenglh and is of a confi gurati on lh ,H \\!~ :: provide confinementlo the cast M in-place concre ·: ~ ;
3.
Tile specified co mpressive strength f' .. sha:i r:~' exceed 35 MPa and the ratio of steel mi l .J;' specified yield strength F,. to concrete spt.-..:ifii, comp ressive strength!'" shall not be less than 6 ; ;Ul .·
4.
The pile diameter is not greater than 400 mm .
Exception:
The length of pile may exceed 30 rim es the diameter provided th e design and installation of the pile foundation is III accordance with all approved foundation
307.4 Precast Concrete Piles
iflvestigatioll report.
307.2.2 Allow,,!)le Stresses The all owable compressive stress in the concrete shn ll not exceed 0.3V·,.. The allowable compressive st ress or reinrorcement shall not exceed 34 percent or the yie ld Mrenglh or the steel or 175 MPa.
307.4.1 Ma(erials Precast concrete piles shall have a specific i comprc<;si ~a reJlglhf'•. of not less than 20 MPa. and sh,JI! dey .. ,." compress ive strength of not less than 20 MPa I.. ere dri ving. 307.4.2 Reinforcement Tics The !ongitudimd reinforccmcnt in driven precast (' fl JlO pil es shall be laterally tied with steel lies or wire · . Tics and spirals shaI! nOt be spaced morc than ·
National Structu ral Code of IIle P!1ilippin8s Gill Edition Volume 1
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CHAPTER 3 -- General & Excava/ion _and Fills
ap,lrt, centcr to cellter, for a di stance of 600 mill frol11 the ends and not more Ihan 200 mm elsewhere. The gage o f
lics and spiraJs shall be as follows: I.
For piles ha ving a diameter of 400 mill or less, wire shall nol be smaller than 5 min ;
2.
For piles, having a diameter of morc: than 400 mil1
loads. The effective prestress in the pile sh;i;l ;;',l( h' ; ("'~::; than 2.5 MPa for pi les up (0 10 III in !enrol: :/!\~ L,; piles up to 15 m in length , and 5 MPa Iv: I ) ' ' ' : ' t~ · ..: . . ~~ r than 15m in length. T he compressive stress in the concrete du e !o c".!'::-na ll y app lied load shall not exceed:
and Jess than 500 mm, wire shall /l ot be smaller than
. -,!'.' .)
f) mm; a.nd
3.
For pi les having a diameter of 500 wire shall not be smaller than 7 mm.
mll1
and larger.
If'<'
307.4.3 Allo wa ble Stresses Precast concrete piling shall be designed 10 res ist stresses induced by handling and dri ving ns well as by loads. The allowable stresses shall not exceed the values specified in Section 307.2.2. 307.5 Precast (Prctensioncd)
Prestressed
Co ncrete
wherc:
Piles
307.5.1 Malerials
Precast pres tressed concrete piles shaH have a specified co mpressive strength[.. of not less than 35 MPa and shall develop a com pressive stren gth of not less than 27 MPa before driving. 307.5.2 Rei nfo rce ment
307.5.2. 1 Longitudinal Rei nforce ment The longitudinal reinforcem ent shall be high-tensil e se ven -wire strand conform ing to ASTM Stand ards. Longitudinal reinforcement Sh311 be I,Herally lied w ith sleel ties or wi re spirals. 307.5.2.2 Tra nsverse Reinfo rce ment
~ effective
prestress stress on the gros!':.
:,t'{'!; '! :i.
Effective prestress s hall be based on an :i :-':": iir: , ~- ,: i:.,;:: J: 200 MPa in the prestressing steel. The allow i1l, k~ .', irt:... ·~ ii , the prestressi ng stee! shall not exceed the v
Tics or spiral reillforcemclll shall nol bc sp:lccd more th an
75 111m apart, ccnter to center, ror II distance o r 600 mm
Exception:
from the ends and nol more than 200 I11Ill elsewhere. A( each end of the pile, the first five ties or spirals shall be
When justified in accordance with Sectioll .·{f).Ii. J? 'ii allowable axial stress may be increased aboV(! rl5 iliii'" alld 0.35F}~ hut Jhall llot exceed O.5Fr
spaced 25 mOl center to center.
For piles having a diameter of 600 mill or less, wire shall not be smaller than 5 111111 . For piles having a diameter greater than 600 I11Ill bu t less tha n 9(X) mill, wire shall not be smaller (lw l1 6 mrn. For piles having a dinrllelcr grcfltcr (han gOO mill, wire shall not be smaller Ihan 7 mill.
l
307.6.3 Minimulll Dimensions Ii -piles shall co mply with lhr
Seclions of dri ven rollowing:
1. The flan ge projection shall not exceed 14 li~l W" :lle minim um thickness of meta! ill either tl w n·"" the web, and the flnnge widths shall not :J~' k " .' 1')0 percenl of the dcplh or the secti on. 2.
307.5.J All owa ble St resses
The nominal dcp(h ill the direction of the '. \( L ... .. ;"" not he less than 200 mill.
Precast prestressed piling shall he designed 10 resist stresses induced by handling nnd driving as \vc ll as by
Assoclo tiotl of Slrllclural
'
En9Ine('~r s
of the Philippines
CHAPTER 3 - General & Excavalion and Fills
Flanges anti webs shall have thickness of 10 mm ,
il
3· 19
minimum nominal
: ~ecljonS of dri ven pipe piles sha ll have nn outside
:: diam eter of not less than 250 mill and a minim um . thickness of not less than 6 mm. , 307.7 Concrete·I"illed Steel!'ipe Piles 307.7.1 Material The sleel pipe of concrele- filled stee l pipe pi les shall
conform
(0
onc of the material speci ficati ons listed in
Section 50 1.3. The con crete in concrete-fill e d steel pipe piles shall have a spec ified co mpressive strcnglh [,c of not less than J7 MPa.
!I i-
f
I !
308.1 Gelleral In Seismic Zones 4, the further requirements of thi s sec tion shall apply to the des ign and cons truction of foundati ons, foundation compone nts 'and Ihe connecti on of superst(1Jcture elements thereto. See Sec ti on 421.10 for additional requirements for S(l1lctural concrete foundati ons resisting seismic forc es.
308.2 Foundation and Geotechnical Investigations 307.7.2Allowable Stresses The all owable axial stresses shall not exceed 0.35 of the minimum specified yield strength F.,' of the steel plus 0.33 of the specified compress ive slrcllglh /'(' o f concrete, provided J'~' shall lIo t be assumed greater than 250 MPa for computational purposes.
Where a structure is de termined to be in Seismic Zone 4 in accordance with Section 208.4, an investigation shall be conducted and shall include an evaluation of the following potential hazard s resu ltin g from eart hqu ake motio ns: slope in stabilit y. liquefac lion and surface rupture due to faul!ing or la te ral spreading.
~CepliOIl:
In addition , the foll owi ng in vestigations sha ll a lso be met:
When justified ill accordance with Section 306.12, /he pllowable stresses may be in creased to 0.50 F)"
I.
307.7.3 Minimum Dimensions
2.
Driven piles of uil iform scction shall have a nomina l outside diamete r of not less than 200 Illlll . 117~!}\:·t·;
.
. ,.
A dctcnnination of lateral pressures on basement and re taining walls due to earthquake motions. An assessment of potenti al consequences of any
ligueracrion
and
soil
srrengrh
loss,
including
estimati on of diffe ren ti al seule mcm, lateral move ment or reduction in foundation soil~be aring capac ity, and shall address mitigation meas ures. Suc h meas ures shall be give n consideration in the design of the s truc ture and can include but are not limitcd to ground stabili zation. selec (i on of appropriate foundation type and depths, selection of appropriate structural systems 10 accomm odate antic ipated displacements Or any combination of these measures. The potential for liqu efaction and soil strength loss shall be evaluated for site peak ground accelerati on magnitudes and source characteristics consistent with the design earthquake ground motions. Peak ground acceleration s hall be determined from a si l e~ s pecifjc stud y takin g into account soil amplifi cation effects, as speci fi ed in Section 208.4.
308,3 Footings and Foundations Where il struclUrc is assigned (0 Se ismic Zone 4 in accordance with Section 208.4 , individual sprcad footings fo unded on soil de fined ill Sec ti o n 208.4 .3 as Soil profile Type SE or SF shall be interconn ected by ti c beams . Tic beams shall be capabl e of carr yi ng, in tension or co mpress ion, unless it is demon strated th at equival ent restraint is provided by re inforced conc ret e beams within s labs 011 gmde or reinforced concrete slabs 011 grade.
Ncll iOl'w l Struc tural Cod e of the Philippines 6
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Edition Volume 1
3-20
CHAI'TEI1 3 _. General & Excavation and Fills
308.4 Pier and Pile Found.tio Where a stmclUre is assigned to Seismic Zo ne 4 in accordan ce Wi lh Seclion 208.4 •• he following sha ll appl y. Individual pilc caps, piers or piles shall be interconnected by ties. Tics shall be capable of carrying, in tension and com pression . 10 % of Ihe maximum axial load unless it can be demonstrated Ihal cquiv;'l lcnt restraim is pro vided by reinforced concrete beams within slabs on grade, reinforced concrete slabs on grade, confinemen! by competent rock, hard cohesive soi ls or very dense granular soi ls. Conc rete shall have a specified compressive strength of not less than 21 MPa at 28 days.
Exception:
Pie rs supporting foundation walls, isolated interior posts detailed so the pier is not subject 10 lateral loads. lightly loaded exterior decks and palios alld occupancy category IV and V specified in Section 103 not exceeding two stories of light-frame construction, are flot subject to interconnection if it call be shown the soils are of adequate stiffness, subject to the approval of the building official. 308.4.1 Connection to Pile Cap
For piles required to resist up lift forces or Lo pro vide rotati onal res traint, design of anchorage of piles into {he pile cap shall be provided considering {hc combined effect
'0
of axial forces due '0 uplift and bending momen .. due fixity (0 the pile cap. Anchorage shall deve lop a min imu m
or
25 perccnt of the strength of th e pile in (e nsio n. An chorage into the pile ca p shall be capable of developing the following: I.
In the case of uplift , lhe lesser of lhc nominal le nsile strcngth of the longi llldi nal reinforcemcnt ill a conc ret e pile, or the nominal te nsile strength of a s[eeJ pile. or (he pile uplift soil nomina l st rength factored by 1.3 or the axi al tensi on rorce res ulting from the load combinations of Secti on 203.
2.
1n the case of rotational restrai nt, the lesser of the ax ial and shear forces and moments resulti ng from the load combina tions of Section 203 or development of the full axia l, bendin g and shear nominal stren gth of .he pile.
wi thin seven pile dia mclers of the pile cap and lhe interfaces of soft (0 mediu m stiff clay or liquefiable strata. Grade bea ms shall be des igned as beams in accord ance Secti on 4. When grade beams have Ihe capacity to rcsis t the forces from the load combinations in Section 203. 308.4.3 FlexII,.al Slrength
Where the vcrtical la t c ral ~ro rce ~re s i s tin g elements are (';ol umns, the grade bea m or pile eel p nex ural strengths shall exceed the column flexural strength. The connection between batter piles and grade beams or pile caps shall be designed to resi st the nominal st rength of lhe pile actin g · (IS a short column. Bauer piles and the ir connection shall be capable of resisting forces and moments frol11thc load co mbinat ions of Sectio n 203 . 308.5 Driven Pile Foundations 308.5.1 Precast Connete Piles Where a struclllre is assigned to Seismic Zone 4 the iongilUdinal reinforce ment wi th a min imum steel ratio o f 0.0 1 shall be provided throughout the Icngt h of precast concrete piles, Within three pil e diarnct ers of the bottom of the pile cap, th e longitudiJl
or
308.S.2 Precast Prestressed Piles Where a stl1Jclurc is assigned \0 Seismic Zone 4, the following shall "ppl)'. The mi nimu m vo lulIletric ratio of spira! reinforcement shall not be less than O.()()7 or the amount required by the follow ing formul a for th e upper 6 11') of the pi Ie. p.=OI2J,.jJ••
where :
I.
I,," 308.4.2 Desigll I)ct;:lils for Pie rs, I)ilcs and Gracie Beams
Pie rs or piles shall he designed and constructed 10 withsta nd Ill
(308.5.1 )
p,
Spccilied compressive strl~ nglh of ro ncrcte, MPa = Yi eld stren gth of spiral rc inforc ell1 ~~n t. 586 MPa ;:: Spiral reinforce ment index (vol ume of spiral/v()lu me of core)
At least o n c~h a lr the vo lullletri c ratio requ ired hy Eq. 4~1 sh;lI ! he provided below t!w upper 6 III or the pi le. The pile cap co nnection hy mea ns of dowels. Pile cap connect ion by meall.'i or developi ng pile. reinforcin g strand is pe rmilled provided lhat th e pik reinforcing strand rC"wlts in a duclile conllcclioll.
Association of Structural Enqlneers of the PhilipPInes
CHAPTER 3 - General & Excavalioll and Fills
Ihe total pile length in Ihe soil is 10.5 III or less, the
transverse rei nfo rcement in the ductile region shaH Ouough tile length of the pile. Where the pile length 10.5 m. rhe ductile pile region shall be taken as greater of 10.5 In or the distance from th e underside of pile cap to the point of zero cu rvature plus three :' times the least pile dimension. ; In the ductile region, the center- io-ccillcr spacing of th e
spirals or hoop reinforcement shall not exceed olle-fifth . of tJle least pile dimcllsiOIl, six times the diallleter of the
longitudinal strand, or 2(Xl mill, whichever is smaller.
i
I
but nOl less than: A"
Where lhe transverse reinforcement consists of circular spirals, the volumetl;c ratio of spiral transverse reinforcemel1l in the ductile region shall comply willl the following: p,
=O. 1 2.L.(~ - I )[~ - 1.41'] f'h
A,, ,
2
(308.5.2)
f..A~
but not less than :
and need nO[ exceed: (308.5 .4)
p, = 0.021
where: 2
A" "" Pile cross·sct"tional area, mm Ad = Core area defined by spiral outside diameter, m lll ~
f c = Specifi ed compressive stre ngt h of concrelc, MPa
hh = Yield strength of spira! rc.inforce ment :s; 586 MP.I I' = Axial load on pile, kN =:
(308.5.6)
I,."
= S 483 MPa
he
:= Cross~seclional
s
P
dimension of pile core measured center LO ce nter of hoop reinforcement, mm '= Spacing of transverse reinforcement measu red . along length of pile. mm = Axial load, N :: Cross~sec tional area of tran sverse reinforcement, mm
A,
f.·
2
:: Gross area of pi le. 111m2 Specifi ed compressive strength of concrete, MPa
:=
The hoops and cross ties shaH be equi valent to defonned bars not less than IOmm ill size. Rectangular hoop ends shall terminate at a comer with seismic hooks. Outside of the length of the pile requiring transverse confinement reinforcing, th c spiral or hoop reinforcing with a volumctric rati o not less than one· half of that required for transversc confinement reinforcing shall be provided . 306.6 Cast-In-Place Concrete Foundations
(}08.5.3)
Ps
=O. 1 2Sh,(.L)[~+ lAP] f,. 2 f,A,
where:
A.th
" Circular spiral rcinforcClllcnl shall be spliced by lapping one full tum and bending the end of the spiral to a 90degree hook or by usc of a mechanical or welded splice.
3· 21
Volumetric ratio (volumc of spiral! volume of core)
This required amou nt of spiral reinforcemellt is pcrmitled to be obtained by pro viding an inner and outer spi ral. When transverse reinforce melll consists of recta ngular hoops and cross tics, th e total c['()ss ~ sccti ()Jlal are a of lateral transverse rcinforccmcill in the ducti le region with spacings, Jnd perpcndicular 10 dimension, he. shill! confonn 10:
Where a stJUcture is assigned to Scismic Zone 4, a minimum longitudinal reinforcement ratio of 0.005 shall be provided for uncased cast~ in~place drilled or augered concrete piles, piers or caissons in the top o ne~half of the pile lengt h a minimum length of 3 In below ground or lhroughout the flexural length of the pile, whichever length is greatest. The Oexurallength shall be taken as the length of the pile to a point where the concrete section cracking moment strength multiplied by 0.4 exceeds the requ ired mo me nt strcngth at lhal po int. There shall be a minimulll of four longitudinal bars with transverse confinement reinforcem ent provided in the pile within three tillles th e least pile dimension of the bottom of the pile cap. A transverse spi ral reinforcement rat.io of not less than one·half of that required in Section 410 for ot her than Soi l Profi le Type S£" SF or as determined in Section 208.4.3 or liquefiable sites is permitted. Tie spaci ng throu ghou t Ihe remainder of the concrete section shall neither exceed 1 2~ longiludinal~bar diameters, o ne~half the least dimension of the sec ti on, nor 300 mm. Ties shall be a min imum of 10 fIllll bars for piles with it least dimcnsion lip to 500 n1m , and! 2 111m bars for larger piles.
N;:llional Structural CorJe of tile Philippines
(, !II
Edition Vol ume 1
3-22
CHA PTE li 3 - General & Excaval ion and Fills
309.1 Special Foundation Systems Special foundation sys tems or materials other than specified in (he fore goi ng Sections may be introduced provided thai such syslems can be supported by caic ul:ltions and theory to be providi ng safe foundati on sohtlions and when approved by the engineer-o f-reco rd. The special foundati ons solutions for incorporati on into the foundation should have proven track record of successful usage in similar applications.
309.2 Acceptance and Approval Structure support on improved ground using such spec ial systems or proprietary system s may be approved s ubject to su bmittal of calculations and other proof of acceptance
and usage.
309.3 Specific Applications Specialty foundation systems may be applied or used specifically to address any or combinations of the improveme nt, soil following: beari ng ca paci ty liquefact ion mitigati on, slope stabilit y enhancement. control and/or acceleration of consolidation settlements or immediate settlements, increa<;c in soi l shear strength and capacity. sliding resistance. increased pull o ut or overt urning capacity. special anchors in soil and rock and other beneficial effects. COnlrolled low strength materi als (CLSM) 10 reduce fill loads may be allowed for use where ap plicable_
Associ8tion of Structura l Engineers of tile Philippines
NSCP C101·10
Chapter 4 STRUCTURAL CONCRETE NATIONAL STRUCTURAL CODE OF THE PHILIPPINES VOLUME I BUILDINGS, TOWERS AN[) OTHER VERTICAL STRUCTURES , SIXTH EDITION
Associa ti on of Structural E nginee r s of th e Philippines Suite 7 13, F uture Poin t Plaza Co nd omiuiulll I 11 2 Pana), Ave nu e, Q uezo n C ity, Phil ipp ines 11 00 Tel. No : (+632) 4 10-04H.I Fax No.: (+632) 411-8606 ElIl a il: ;tscponlinc(ci,lglllilil .com Weusitc : ht tp ://www.asCI}Onli nc.org
Nationa l S tructur;:i! Code of the Philippines
6! h
Edition Volume 1
CHAPTI'J14 . Concrete
4· '
Table of Contents 401 • GENERAL .................................................................................................................................................. 7 ....... ..... ..... ........ ............................................................................................................................ 7
.2 Scope .... ....................... ................. .. ............... ............. .............. .. ........................................... .. ................... 7 402 • DEFINITIONS ...................................................... ..... ................................................. ................................ 8 :.- .... -.~" 403 ~ SPECIFICATIONS FOR TESTS AND MATERIAI.S ................. ,............... ..................... ............... 13 .. ................... . .. 13 .... ............. Tests of Ma terials ........ .... .. ... ......... .. ........... .. ........................ ........ 13 Ccnlcnt... .. .. ...... ... ....... .... .. ..... .. . 13 Aggregates .. .. ....................... ........................ ...... ............... .. .. 13 ........ ...... .. ... 13 Water .. ....... .......... .... .... S teel Reinforcement.. ..... . .... .... .... . ... ..... ... .. .. ............... 14 Admixtures ", ... ," ..... ..... .... ... .. ... 15 Storage of Materials.. ............ ......... ......... .............. ............... .. ....... ....... 16 S tandards Cited in this Chapter ........................... ... ...... .. .......... ... ... .... . .... ........ ..... .. .......... ........... 16 • SECTION 404 . DURABILITY REQUIREMENTS ...... .......................................................... ....................................... 18 ............... . ......... . ... .... ..................... 18 · 404.2 Definitions ... .. ... ................. .. ............ .. .... .. ... .. ....... ... 18 ... 19 404.3 Genera l . ...................... ......................... ........................... ........ 404.4 Exposu re Categories and Classes. .. ...... .... .. .. .. 19 404 .5 Special Exposure Co ndi tions. ....... .............. ........ ........ .............. . .. .. .................... 19 404.6 RcquiremcllI s for Concrete Mixtures .. :. ............................ ..... ... . .... ............. .. 19 . ... 19 404.7 Alternati ve CemelHitious Materials for Sulphate Exposure. .. 404.8 Water-Cem en titi ous Materials Ratio .... ..... .. ...... ". . . ..... 19 404.9 Corrosion Protection o f Re inforce ment .. ................ ........... . ............................... 19 SECTION 405 ~ CONCRETE QUALITY, MIXING AND PLA CIN G ....................................................................... 21 405.1 Notations.. .... .... ... .... .. .. .... .. ... ...... . . .... .. ... ... .... 2 1 405.2 Geo eral ........ .. .. .. ....... 21 405.3 Selection of Concrete Proportions .. ... .. ............ ..... ............... ... 21 405.4 Propollio ning on the Basis of Field Experience and Tri .d Mixtures. or Both. .. ..... ... .... . ...... 22 405.5 Proportioning without Field Experience or Tri al Mixtures .. .... 23 405.6 Average Strength Reducti on .. .......... .... .. .............. .... .... ..... 23 405.7 Evaluat ion and Acceptance of Concrete ... . ......... 23 405.8 Prepa ration of Equipmcill and Place of Deposit ................. . .. 25 405.9 Mixin g. .. ...... .... ... . .... .... .... .. .... 25 ........................ .. ...... 25 405. 10 Conveying ................... ................ ...26 405. 11 Deposi ting ............... ............ .. ..... .... ........ .... .. ... 26 405.12 Curing.. 4.05.13 Hot Weather Requirements. ............ .. .... ................ ... .... .... ....... . . .. .. 26 SECTION 406 . FORMWORK, EMBEDDED PIPES AND CONSTRUCTION JOINTS ..................................... 26 .... .......... .. .. .. ..... 27 406. 1 Design of Forrmvo rk .... ............................ 406.2 Removal of Forms, Shores and Re sllOring .... .. 27 406.3 Conduils and Pi pes E.mbcddcd in Concrete. ................ ......... .. 27 ...... .. ...... .............. ... ..... ......... .. ..... . ... 28 406.4 Construction Joi nts ...... ... ... ......... SECTION 407 . DETAILS Oil REINFOR CEMENT .................. ... ........... ......... .................... ............................... .... .... 28 407.1 Notations.. . ...... 29 407.2 Stil ildard '·Iooks.. .. .............. ..... . .. . ...... .. 29 407.3 Minimum Bend Di,llllctcrs..... ................ . .... 29 407.4 Bendin g of Reinforcement. . . .. 29 407.5 Su rfa ce Conditio ns of Reinforcement. . . ... ... . 29 407.6 Placing Rcinfo rcemcnt.. ...... .. .... .... ...... .................... . 29 407.7 S pacing Limils for Re inforcc mcIlL.. . .... 30 407.8 Co ncrete Protection for Reinforce mellt .. 3 1 407.9 Special H. cinforccment Details for Col um ns ...... ... 32 407. 10 Connections .... ... ...... .. .... . .. J:\
4·2
CHAI'lTI14 . Concrete
407.11 Lateral Reinforcement for Compression Members ...... . 407.12 Lateral Reinforcement for Flexural Members .. . 407.1 J Shrinkage and Temperature Reinforcement ..................... . 407.14 Requirements for Structural Integrity ......................................... .. SECTION 408 - ANALYSIS AND DESIGN-GENERAL CONSIDERATIONS ....................................... , ......... j8 408, I Notations .. 408.2 Design Methods" 38 408.3 Loading.. .................................. . 3R 408.4 Methods of Analysis. .................................................................... ............. . 408.5 Redistribution of Negative Moments in Continuous Nonprcstressed Flexural ivicmbers 408.6 Modulus of Elasticity" " .. ,... ,.. ,... "."." .. ,." () ,.. "", .... "".",, .. ,. "" .. ,.. "."",.,,. ,." .. "., .. " 408,7 Lightweight Concrete 408.8 Stiffness . 408.9 Effective Stiffness [0 Determine Lateral Deflections .... 408.10 Span Length ... ,.,." .. ,.. ". 408, II Columns ,. ,."" ... " ......... " .. ,.,. ,.,., .. ,.".,." .. , ."" .. ,.. " .. ,."."" ..... . 408.12 AITangement of Live Load 408.13 T-beam Construction ................................................. . 408.14 Joist Constl1lction .. 408.15 Separate Floor Finish.. ......................................... . .., .. ".·11 ..,,42 SECTION 409 - STRENGTH AND SERVICEABILITY REQUIREMENTS ...............•.................... ,., -12 409.1 Notations .. /. . 409.2 General.. 409.3 Required Strength. , 409.4 Design Strength" 409.5 Design Strength for Reinforcement ................................ . 409.6 Control of Deflections .. SECTION 410 FLEXURE AND AXIAL LOADS ............................................................................... . ................ . .. 10 410.! Notations ....................................................................... . 410.2 Scope .. . ............. ..Ii <) 410.3 Design Assumptions. . . .'.1 (i 410.4 General Principles and Requircmcnts .. . ,... 49 410.5 Distance between Lateral Suppons of Flexural Members. ............ ... ,50 410.6 Minimum Reinforcement of Flexural Members. ........ ,........... 50 410.7 Distrihution of Flexural Reinforcement in Beams and One-way Slabs. .. ............ so 41 O.S Deep Beams, . . S) 410.9 Design Dimensions for Compression Members .. 410.10 Limits for Reinforcement of Compression Members .. . ............ . .............. :)i 410.11 Slenderness Effects in Compression Members.. ....................... .. . ,.. , .. " " .. , ." .. ,.. " .. ""." .. ,., .... " .. ," 410.12 Magnified Moments .. " .. " .. " ... " 410. I 3 Moment Magnification Procedure - Nonsway .............................. . 4 J 0.14 Moment Magnification Procedure - Sway .......................................... .. 410.! 5 Axially Loaded Members Suppo[1ing Slab System. . ................ . 410.16 Transmission of Column Loads through Floor System ................................. .. .. 4! O. J 7 Composite Compression Members.. . ............ . 4 It}. ! 8 Beari ng Strength ..................... . SECTION 411 - SHEAR AND TORSION ................................................................................................. . 41 1.1 Notations .. SI 41 1.2 Shear Strength., 41 J.3 Lightweight Concrete .. 41 1.4 Shear Strength Provided by Concrete for Nonprestressed Members 4! 1.5 Shear Strength Provided by Concrete for Prestressed Members ..... 411.6 Shear Strength Provided by Shear Reinforcement .. 4 J 1.7 Design for Torsion. ..\, 41 !.8 Shear ~ Friction. 4! !.9 Deep Beams. ..................... 65 "
Association of Structural Engineers of tile Philippines
CHAPT ER 4 . Concrete
II i !
·1·3
41 LID Pro visions for Brac kelS and Corbels... ........ ............................................ ....... ......... .................. ........ 65 41 Lll Provisions for Walls ............................................... ........... ........ .............. .......................... . .. ......................... 66 41 Ll2 Transfer of Moments to Columns.. ......... .... .. .. ....... ..... .. ....... .. ... ...... ..................... .. ......... ........................... 67 41 Ll3 Provisions for Slabs and Footings ........ ................ .................................................................................................. 67 SECTION 412 - DEVELOPMENT AND SPLlCES OF REINFORCEMENT ........................................................ 70 412.1 Notations.............................. .. ............................ .... ..... ........ ... .... ............ .. .. . ... ...... ... 70 412.2 Development of Reinforcemcl1l - General......... ... 71 412.3 DevelopmclII of Defonned Bars and Deformed Wi. ~~ in Tension................ . ............. ,... ... ....... ......... ........ 7 1 41 2.4 Development of Defonned Bars in Compression. ............................... "............. .... ... ... ..... ,... 72 412.5 Development of Bundled Bars.:.......................... .. ......... ........................... .................. ........................... ............ 72 ........................................................ .72 412.6 Development of Standard Hooks in Tension ........ 412.7 Development of Headed and Mechanically Anc ho red [ 'cfofmcd Bars in Tension ..... ....... 73 412.8 Development of 'Welded Deformed Wire Reinforcer. l ~nt in Tension .... .... .. ... ..... ".... ... ........ ....... .... . .. .. 73 412.9 Development of Welded Plain Wire Reinforcemenl il Tension..... ...... ... ....... .. ............ ...... ............ ......... .... 73 412.10 Development of PreSlressi ng Strand ................. ............. ...................................................... .............................. .......... 74 412.1 I Development of flexu ral Reinforcement - GeneraL.... .. ..... ,.................... ........... ...... " .. ....... ............. .............. ....... ...... 74 .......................................... ......... ....................... ........ ............ 74 412.1 2 De velopment of Positi ve Moment Reinforcemenl... .. 412.13 Development of Negative Moment Rei nforcement ..... .................. ..... .. .. ................ . ... ...... 75 412.14 Development of Web Rein force ment ........... ....... ... ...... ............ ...... .... ........ ................... .. 75 4 12. 15 Splices of Reinforcement - General...................... ..... ................ .... .. ..... ...... ........... ... 76 ...... .. 76 412.16 Spl ices of Deformed Bars and Defomled Wire in Tensi· \11...... ........... .......... ...................... 412.17 Splices of Deformed Bars in Compression .... .... ................ ................. . ........................................................................ 77 412.1 8 Special Spli ces Requirements fo r Columns .... ..... ............................................. ... ........................................ .. ......... .... 77 412.19 Splices of Welded Deformed Wire Reinforcement in Tens '0"-. ........... .. ............ .. ................................................ ........ 77 412.20 Splices of Welded Plain Wire Reinforcement in Tension .... ....... ........ ......... ............... ..................... 78 SECTION 413 - TWO-WAY SLAB SYSTEMS .................................................................................................................. 78 ......... .............. .. .. ............... ..... ... ....... .......... .... .. 78 413.1 Notat ions ....... ............. ..... .......................................................... 79 413.2 Scope .......................................... ............................. .......... .... . 413.3 Definitions ... ........... .... ........ ............................. ................... .. .. ................. .... ........................ 79 413.4 Slab Reinforcement .... ... .. ...................... ......................... ... ... ............ .............. ....... ........ . .............. . ........ 79 .............. ....... ....... .. .. .............................................................................. 8 1 413 .5 Openings in Slab Systems ........ .............. .................... ..... ................... .. ..... ....... 82 413.6 Design Proced ures ..... 413.7 Direcl Design Method.... .................... ........ ..... .. .. .. ........ 82 413.8 Equivalcl1I Frame Method . .................... ............................ ...... . .... 85 SECTION 414 - WALLS ............. .................. .......................................... ........................... .................................................... 86 414.1 Notations ........... .... .... .............................. ... ........... .... .... ........... 87 414.2 Scope ....... .............. ....... .... ................................ ..... ............. .......................... .... 87 414.3 General .... .. ... ........ . ............. ...... . ...... ........ ...... ............... ....... .............. ........ 87 . 414.4 Minimum Rcinforcemcnt...... .. ...... ....... .... .................. .. .... ....... .. . 87 414.5 Walls Design as Compression Members. .. .. .... .... ... ................ .. ... 88 .................... ........ .............................. 88 414.6 Empirical Design Method ............. ... ......................................... ... 414.7 Non-Bearing Walls. ............. .. ........ .............................. ... ................. ............. ........................... ... ......... 88 414.8 Walls as Grade Beams ........... ....... .............. ........ ........ ........ ..... .. .......... ... .. ........ ............ .... ... .......... ...... .. .................... 89 414.9 Altemale Design of Slender Walls .......................... ... ............................ ... ................... ....................................... ........ 89 SECTION 415 - FOOTINGS .......................................................................... .. . .................................................................... 89 415.1 Notalions. .... .......... ...... ... ...... ........... .... ..... ..... ..... .... .............. . .. .................. .. ...90 415.2 Scope ... ....... .. ... ................ .......... .... ...... ..... ........... ................ ... .... ........... .. ........... 90 4 t5.3l/},;
Nationa! Structural Code of the Philippi ne s 6 Edition Vo lu; !" · ~ 1 1h
4-4
CHAPTEH 4 - Concrete
................... _.................... _............ ... .. .... 92 415.12 Plain Concrete Pedestals and Footings ...................... . SECTION 416 -PRECAST CONCRETE .................................... _ .. .................................................................................... 92 416. i Notal ioTls ........ . .. _..... _.... __ ............. .. ....................................... -- .... -.......... 92 .. .. _.......... _.............. ...92 416.2 Scope_ .... _............................ _........................................... _.. .. ........ _.............. 92 416.3 General .................... . 4 ) 6.4 Distribution of Forces among Members ........................... .
.. ...... ..... ....... _.. _...... 92
............ .. ... 93 .. ......... ........... 93 _.. _93 ...... _................ . ............. 94 416.8 Items Embcdue '[ \ncr Concrete Placement ............... . 416.9 Ma rking aud Ide ntification................ ............... ...................................................................... ....... ... ........ 94 4 16.10 I-Iandling ... __ ... _.. _... _......... ...... _.. _.. ___ ......... _.......... .... ........ ..... _.. __ ...... .... _.. _._ ... _......................... .... _.... _...... _.... _..... 94 416.1 J Strength Evaluation of Precast Construction ..... _................ ..... ,............. ................. .......... ................ ... ........................ 94 SECTION 41 7 - COMPOSITE CONCRETE FLEXURAL Mi;, ..\!8ERS ........................ ................................................... 95 417_1 Nota tions. .. .... _.... .. . .. ........... _ ........................................................................ _................ 95 417.2 Scope.. ..... ........ .......... .. ... ........... _.................................... _........... _ .............. 95 4 17. 3 General .... _.. _.... ...... ............ ...... .......... .. .. _.......... .. .. ...... 95 ................... .. ........ _..... _ .......... __ ...... _....... _............ _............... _........ _.. _........... 95 417.4 Shoring.. .............. 417_5 Yenieal Shear Strength ................... ...................... .. ... _.. _...... _........ .................... _......... _.................................... 95 4 ) 7_6 Hori zontal Shear Strength ..... ................ ........... ....... .. ......... .. ............................................................. ................... 95 417_7 Ties for Horizontal Shear .......... .. _.................. _.. _........... _ .. _.. ___ ............ _........................ _................. _ .. _96 SECTION 418 - PR ESTRESSED CON C RETE .................. .......... ........................................................................................ 97 418_1 Notations ............................ _....... . ....................................................... .. ................ _............ 97 4 18_2 Scope ...... .. _.... _.. _..................... _.. .... ...... ....... .. .... _.... ..... .. ....... 97 418 .3 Gene ral ............ _........... .. .. ........ ... _.......... ........ .... .... ........... .. .. .......... .. .. .... .... 97 ..................... _.... 98 418.4 Design Assumpti ons .. ................... . _...................... 98 418.5 Permissible Stresses ill COllcrc lc - Flexural Members 418.6 Permissible Stress in Prestressi ng Tendons ............... . _............ _.. _..... __ ._ .. _..... ____ .. ___ .. _.......... .. __ ............ __ ...... ___ .... _.. _ .. ___ 99 .. ...... .. .. .. __ .................... 99 418_7 Loss of Prestress ...... _...... _........ _................. .. .. ......................... ............ 99 4 18 .7.2 friction Loss in Post-Tensioning Tendons ... 100 418.8 Flexural Strength ...... _ .................. _ ...... 100 418.9 Limits for Reinforcc mcnt of Flex ural Members .... .100 4 18.1 0 Minim um Bonded Reinforcemcnt 4 I 8. II Stat ically Jnc.kl cl"minatc S tructures ..... .... .............. .... ....... ..... ........ ............. 101 418.12 Compression Members - Com bined Fl ex ural iH' .. i Axial Loads . .... 101 4 18_13 Slab Systems: ...... .. _..................... _ ...... ............ ____ ................. _.... _ .............................. 102 4 18. 14 Post -Tensioned Tendon An chorage Zones. ................... .. .................. 103 4 I 8.15 Design of Anchorngc Zones for Monoslra nd ( Jr Single 16 I11Ill Diamcter Bar Tendons ........... ...... ........... .......... ........ 104 4 18.16 Design of Anchorage Zones for Mullislr:HH!,' J T L' ndons ................................................................................ 104 418.1 7 Corrosion Protection for Unboudcd Prc ~ll ~' .sing Tendons. . . .......................................... .. ............. ......... . 105 4 18.18 Post-Tensio ning Ducts.. .. .. _.. __ ..... .. .. __ .. __ ........ . 105 418.! 9 Grou t for Bonded Prcstressing Tendon ·.......... .... .............. .. ... .......... ... 105 4 18.20 Protcction for Prestrcssing Steel ..... ... ......... .. ...................... 105 4 18.21 Applicat ion and Measurement of Prc" t· .:ssing Forec........ . ............................................................................. 105 4 18.22 Post-Tensioning Anchorages ,mel COl!. tiers ......... ................. . ......... .......... .................... .... .............. ................ 106 4 ! 8.23 External Pust · Tensioning .. .............. ............................. ... . .............. ...... .......... 109 SECTION 419 - SHELLS AND FOLDED PLATE MEMHERS .......... .............. .. ...... __ .............. " .. __ .... .. .......................... ·109 419. 1 Notatio ns .... ......... ... .................... 109 4 19.2 Scope And Definit ions .................. . ................... 109 419.1 Analysis and Design. ......... ....... . ... J 10 4 19.4 Design strength ()f Materials.. .110 419.5 Shell Rci nforcemcIlL .... . .... ....... .... .............. .... .......... ...................... ......... 110 4 19.6 Construction ...... . ..... ......... ................... .................................... 11 1 SECTIO N 420 - STI!ENGTH EY ..II .UATION OF EX ISTING STlWCTURES .............. ........................................ __ ..... 112 420_1 Notations.... __ .. _........ ___ __ __ .. ___ .. __ _ __ ____ ......... __ .. __ .. __ .... _.... ___ ..... 112 420.2 Strength Ev,liulitioll·Gencral ........... __ ........ ... ..... ..... ................. ..... ................. 11 2 416_5 Member Design ..................... ..
416.6 Structural Int egrit y .. 4 J 6.7 Con llection and Bearing Design
CHAPTEli 4" Concreto
4":i
420.3 Determination of Required Dimensions and Material PropcI1ics ...... .................. .............. .. .... 112 420A Load Test Procedure. .............. ......................... ................... .112 420.5 Loading Criteria .................... ........................ ... 113 420.6 Acceptance Criteria ............ .......... ............... ...... . .......... ............... ...................... 113 420.7 Provisions for Lower Load Rating.. ....... . .............. . ...... 113 420.8 Safety ............................ .............. ................. ....... ..... . ......................... 113
\
SECTION 421 - EARTHQUAKE RESISTANT STRUCTURES .................................................................................... II3 421.1 Notations.. ...... ...... .............. ........ . . ............ .............. ..... .. ... 114 421.2 Definitions. ...................................... ......... ..... ..................... .. ... 115 421.3 Genera! Requirements. . .... 116 421.3.0 Mechanical Splices in Special Moment Frames and Special Structural Walls ................... .. ............... ".. II? 42 J.4 Intermediate Precast StI1lc(ural WaJls ..................................... . ............ .. ..................... I J 8 421.5 Flexural Members of Special Moment Frames.. ...... J J 8 421.6 Special Moment Frame Subjected to Bending and Axial Load ............... . ..................... . . I !9 421.7 Joints of Special Moment Frames ..................... ..121 ... ............................. .. .. 122 421.8 Special Reinforced Concrete Structural Walts and Coupling Beams 421.9 Stmcturai Diaphragms and Trusses ................. ..... .......... ...... . 125 421.10 Foundations ................. ....................... .. ......... 127 421.11 Members not Designated as P;:U1 of the Seismic~Force~Resisting System.. . ............... .. ........... 128 421.12 Requirements for Intermediate Moment Frames, Seismic Zone 2. ..................... ........ 129 421.13 Special Moment Frames Using Precast Concrete.. . 130 421.14 Ordinary Momcll! Frames.. ............................. ................................ ...................... .. ... J 31 421.15 Special Structural Walls Constlllcted Using Precast Concrete. ........................... .. .... 131 SECTION 422 - STRUCTURAL PLAIN CONCRETE ..................................................................................................... 132 422.1 Notations.. ....................... .. .... 132 422.2 Scope.. ................ .............................. ... .............. ................... .. ...... 132 422.3 Limitations ........................................................ .. . ............... 132 422.4 Joints.. .. . 132 422.5 Design Method. ....................................................... .. ........... 133 422.6 Strength Design .... ........ . .................... . .. .......... .. . .. ... 133 422.7 Walls ....................................... .. ....... 134 .... 134 422.8 Footing ........................................ . 422.9 Pedestals ..................................................................................... .. . . ........... 135 422. JO Precast Members ...................................................................... . . ............ 135 422.1 J Plain Concrete in Earthquake-Resisting Structures. ................. 135 SECTION 423 - ANCHORAGE TO CONCRETE .......................................................................................................... 136 423. J Definitions.. ..................... .. ......... J 36 423.2 Scope. .. ............. 137 423.3 General Requirements. .. .. ....... . ........... ..... .. ........ ! 37 423.4 General Requirements for Strength of Anchors.. . ... 138 423.5 Design Requirements for Tensile Loading.. . ........ 139 426.6 Desing Requirements for Shear Loading.. .......... 141 423.7 Interaction ofTensiie and Shear Forces.... .............. 143 423.8 Required Edge Distances, Spacings, and Thickness to Preclude Splitting Failure.. .143 423.9 Installation of Anchors ................. .. ... ............... .. .. .......... 144 SECTION 424 - ALTERNATE DESIGN [I.1ETIIOI) ....................................................................................... .................. 144 424.1 Notalions.. .... 144 424.2 Scope. .. .. ......... 145 424.3 General. ............. ........................................... . ............ .... ................. .. ... ........... .. .. 145 . ... 145 424.4 Permissible Service Load Stresses .. 424.5 Development and Spliccs of Reinforcc1llcrll... ... 145 424.7 Compression Members With or Without Flexure.. ..146 424.R Shear and Torsion.. .. 146 SECTION 425 - ALTERNATIVE PROVISIONS FOR REINFORCED AND PRESTRESSEI) CONCRETE FLEXlJ RA LAND COM PRESSION [\oj EM BEllS .............................................................................................................. 148 425. I Scope. . .. 149
N;l!IOmll ~;!rllctlJr,cl) Code of the P!11lipPlnes
G!it
Edition Volume 1
4·6
CHAI'TEfi 4· Concrete
425.2 Redistribution of Negative Moments in Continuous Non-Prestressed Flexural Members ................... ". .. ............. , 1,'19 SECTION 426 - ALTERNATIVE LOAD AND STRENGTH REDUCTION FACTORS .............................................. 150 SECTION 427 STRUT AND TIE MODELS ....................................................................................................................... 152 427.1 Definitions .............. . ................. ................ 152 427.2 Strut-andTie Model Design Procedure.. ........................ ...................................... ............................... .. ....... 157 427.3 Strength of Struts.. . . ... ..... ............. . ............................ 157 427.4 Strength of Tie$.. ......... 158 ............. ........ ............................... .. ....... 159 427.5 Strength of Nodal Zones..
Association of Structural Engineers of the Philippines
CHAPT ER 4 . Concrete
4·7
401.2.7 Concrete on Sleel form Deck 401.2.7.1 Design and constructi on of structural concrete
slabs cast on stay-in-place. noncomposi te steel foml deck are governed by this chapter.
401.1 Nolalion fe
:;:: speci fled co rnprcssi ve strength of co ncrete, M Pa
40).2 Scope 401.2.1 Thi s dwptcr prov ides minimum req uirement s for the design Clnd cons truc tion of structural concrete clements of any building .or othe r structure under requirements of the
Na.ional Building Code of .he Philippines of which .his Secti on of the National Structural Code of the Philippines, Volume I. forms a part of. This section also covers the strength eva lu ati on o f existing concrete stru ctures. For structural concrete,
r.· shall not be less than 17 MPa.
401.2.7.2 This chapter docs not govern th e co mposite design of structural concrete slabs cast on stay-ill-place, composite steel form dec k. Co ncre te used in the co nstruc tion of such slabs shall be governed by Sec tions 40 I 406 of .his chap'cr, where appli ca ble. Porti ons of
'0
suc h slabs designed as re inforced co ncrete are govern ed by
.his Chapter.
401.2.8 Special Provisions for Earthquake Resistance 401.2.8.) In regions of modera.e (seismic Zone 2) o r high seismic risk (seismi c Zone 4). provisions of Section 421 shall be s •• isfied . Sec Sec.ion 421.3.1.
No maxi mum value of Ie shall apply unl ess restricted by a
f
I
speci fi c code pro vision.
401.2.9 This chaptcr does not constructi on of tank s and reservo irs.
401.2.2 Thi s chapt er shall govern in all matters pertaining to the design, co nst ru cti on, and materi al properties of slmclUm] conc rete clements wherever this chapter is in con m e t with req uirements contained in oth er stnndard s
referen ced in this chapter. 401.2.3 Design and construction of one- and two-family dwellings a nd multi ple s ingle-family dwellings
cle sign
and
Guidance on design and construction of concrete tanks and reservoir shall be obtained frolll the American Concrete IIlS!i.u.e ACI 350·0 I or ACI 350·06 "Code Requirements fo r Ell virollmenw{ Engin eering Concre te Slru cru res" unless suffi cient supponin g ev id ence can be obta ined from recogni zed literat ure.
(townhouses) and the ir accessory struclU res will be cove red by provisions of the National StruclUral Code of the Philippines, Volume III . Housing.
401.2.4 For unu sua l structu res, sllch as arches. tanks , reservoirs, bills and silos, blast-resistan t st ructures . and chimneys,
govern
provisio ns of thi s chapter sh~1I govern where
applicable. See also 422.2 .3. 401.2.5 Thi s chapter does not govern design alld installat ion of portions of COncrete piles and drilled pi e rs embedded in ground except for stm cllJrcs in regions of hi gh seismic risk OJ' assigned to hi gh seismic performance or design ca tego rie s. Sec Sec ti on 421.10.4 fo r require me nts for co ncrete piles, drill ed piers. and caissons in stru ctures in regions o f hi g h scismic ri sk or ~Issig nc d to high sc is'mic performan cc or des ign Gl tcgorics ..
401.2.6 Thi s ch apt e r docs not govern design and construction o f soi l slIpPor1cd slabs , unless lhe slab transm it!>. vcnical l o~ds from other portions of the structllre to thl! soil. 4
Nation ;:·ll Slruc.:tlJl"li Code o f th e Pt1itippines GIl> Edition Votunw 1
4,8
CHAPTU14 ' Concrete
wires, or single bars larger than 16 mil) diameter, that satisfies Section 418.22.1 and the bearing stress and minimum plate stiffness requirements of AASHTO Standard Spec(fic(lfiof!s Jor Highway Bridges, 17'" l:-eJitioJl, 2002, Division I, Seclions 9.21.7.2.1 through 9.21.7.2,4,
~Jj:QWJQN,,4QZ
DEFINITIONS The foHowing terms are defined for general usc in this chapter. sections.
Specialized definitions appear in individual
ADMIXTURE is material other than water, aggregate, or hydraulic cement used as an ingredient of concrete and
added to concrete before or during its mixing to modify its propcl1ics.
AGGREGATE is granular material, slIch as snnd, gravel, crushed stone and iron blast-furnace slag, and when used with a cementing medium forms a hydraulic cement concrete or mortar. AGGREGATE, LIGHTWEIGHT is aggregate with a dry, loose weight of ! 120 kg/nY' or less.
AIR-DRY WEIGHT is the unit weight of a lightweight concrete specimen cured for seven days with neither loss nor gain of moisture at 15° C to 2r C and dried for 2 I days in 50 ± 7 percent relative humidity at 23<1 C ± 1.1 () C. ANCHORAGE DEVICE IN POST·TENSIONING is a device used to anchor tendons to concrete member; in prctensioning, a device used to anchor tendons during hardening of concrete. ANCHORAGE ZONE IN POST·TENSIONED MEMBERS is the portion of the member through which the concentratcd prestressing force is transferred to the concrete and distributed more uniformly across the section. Its extent is equal to the largest dimcnsion of the cross section. For intcrmediate anchorage devices, the anchorage zone includes the disturbed regions ahead of and behind the anchorage devices. BASE OF STRUCTURE is Ihal Icvel at which Ihe horizontal earthquake ground motions arc .assurlled to be imparted to a building. This Jevel docs not necessarily coincide with the ground level. Sec Section 421. BASIC MONOSTRAND ANCHORAGE DEVICE is an anchorage device used \vith ;lIlY single strand or a sin,glC' 16 I11Ill or smaller diameter bar that satisfies Scction 41 B.22.1 and the anchorage device requirements of the PostTensioning Institu(e's "Speciflcatio/l fo/' UlI/)OIl(/e(/ Single .)', /'(111(/ Tel/(/olls ".
BASIC MULTlSTRAND ANCHORAGE DEVICE IS an anchorage device used with multiple strands. hal'S or
!\ssocinIIOI\ of
BONDED TENDON is a prestressing tendon that is bonded concrete either directly or through grouting.
to
BOUNDARY ELEMENT is that portion along stltldural wall and structural diaphragm edge strengthened by longitudinal and transverse reinforcement. Boundary clements do not necessarily require increase in the thickness of wall or diaphragm. Edges of opening within walls and diaphragms shall be provided with boundary elements as required by Section 421,8.6.2 or 421.9.7,5, Sec Section 421. CEMENTlTlOUS MATERIALS arc materials as specified in Scction 403 which have cemcnting value when used in concrete either by themselves, such as pOitland celllent, blended hydraulic cements and expansive cemem, or such materials in combination with fly ash, raw or other calcined natural pozzolans, silica fume, or ground granulated blast-furnacc slag. COLLECTOR ELEMENT is an elemenl that acts in axial tension or compression to transmit earthquake-induced forces between a structural diaphragm and a vertical clement of the seismic-force-resisting system. See Section 421.
COLUMN is a mcmber with a ratio of height-to-Ieastlateral dimcnsion of 3 or greatcr used primarily to support axial compressive load. For a tapered mcmber, the least lateral dimension is thc average the top and bottom dimensions of the smaller side.
or
COMPOSITE CONCRETE FLEXURAL MEMBERS arc concrete flexural members of precast and cast-in-place concrete clements, or both, constructed in separate placements but so interconnected that all clements respond to loads as a unit. COMPRESSION·CONTROLLED SECTION is a cross section in which the net tensile strain in the cxtreme tcnsiOll steel at nominal strength is less than or equal to the c()lllprcssion"colltrollcd strain limit. COMPRESSION·CONTROLLED STRAIN LIMIT is the net tensile strain at balanced strain conditions. Sec Section 4 J 0.4.3.
CONCHETE is a ll1ixture of portland cement or any other hydraulic CClllellt, line aggregate, coarse aggregate (tIle! watcr, with or without admixtures.
:~)tnlClllI ' ;ll r:nCJllw~r;I·s
of
th('~ Philippin(?~,
CHAPTER 4 . Concrele
. CONCRETE, NOIlMALWEIGHT is concrete containing only nggregate Ihat co nforms to ASTM C33. . CONCRETE, SAND-LIGHTWEIGHT is lightweiglll concrclc cOiliaining only norm al weight aggregate IhaL confonns to ASTM C33 and only lighlweighl aggregate that confonns to ASTM C330. SPECII'IED COM PRESS IV E CONCRETE, STRENGTH OF (j',) is the compressive strength of concrete used in design and evaluated in accordance with provisions of Section 405 in MPa. Whenever the quantity f, is under a radica l sign, square root of numerical val ue only is intended, and resuh has units of MPa. CONCIlETE, STRUCTURAL LIGHTWEIGHT is concrete containing lightweight aggregate that conforms to " Section 403.4 and has an air-dry unit weight as determined by "Test Method for Ullit Weight of Smlclurai Lightweight COllcrete" (ASTM C 567) not exceeding 1840 kg/nI'. In this code, a li ghtwe ight concrete containi ng on ly li ght we ight coarse and fine aggregates that co nform to ASTM C330 is termed "concrete, all-lightweight ", and lightweight co ncrete containin g li ghtweight aggregate and an equilibrium density, as determined by ASTM C567, betwee n 1440 kg/m) and 1840 kg/m3, is termed "concrete, Ji gh twcight."
4-9
hooks with at least six-diameter extension at the other end . The hooks shall engage peripheral longiludinal bars. TI,e 90-degrce hooks of two successi ve crosslies engaging the same longitudinal bars shall be alternated end for end. See Sections 407,421. CU Il V ATURE FRICTION is friction resulting from bends or curves in the spccifi ed prestrcssing tendon profile. DEFORlVlED REIN FO R CEMENTS are deformed reinforcing bars, bar and rod mats, de(c'nned wire. welded smooth wire fabric and welded deformed wire fabric conforming 10 Section 403.6.3. DESIGN DISPLACEMENT is the total lateral displacement expected for the design-basis earthquake, as required by the governing code for earthq uake-resistant des ign. See Section 42 1. DESIGN LOAD COMBINATIONS are the combinati on of factored loads and forces in Secti on 409.3. DESIGN STORY DRIFT RATIO is the relative difference of design displacement in between the top and bottom of a Slory, divided by the Slory height. See Section 421 .
CONNECTION is a region that joins two o r more Secti on 421, a con nection also refers to a regio n that joins members of which one or more is precast, for whi ch the following more specific defini ti ons apply:
DEVELOPMENT LENGTH is th e lenglh of embedded rei nforcement required to develop the design strengl h of reinforcemem at a criti caJ sectio n. See Secti on 409.4.3.
DUCTILE CONNECTION is a connection Ihal experie nces yielding as a result of the. earthq uake design displacements.
reduce the amount of negative reinforcement over a column
members. In
DIlOP PANEL is a projection below the slab used to
STIlONG CONNECTION a connection Ihat remains elas ti c while adjoining members experience yielding as a res ult of the cal1hquake design displacements. CONT RA CT DOCUMENTS · arc documents, including the project drawings and project specifications. covering the requ ired Work . CONT RA CTION JOINT is a formed, sawed, or tooled groove in a concrete structure to create a weakened plane and regulate Ihe location of cracking resu lting frol1l the dimcnsionnl chnngc of different parts m·lhe slnlClU rc . COVE ll, SPECIFIED
CONCRETE is Ihe diSl.nce
between the outermost surface of embedded reinforcement and thc closes t (lu ter surrace of the concrete indica ted o n
design drawings o r in project specificat ions.
c nOSSTIE is a (';OlllinliO liS reinforci ng bar ha vi ng a seismic hook a\ one end and a hook not less than IJO-degrcc
or the minimum required slab thickness. and to increase the slnb shear strength. Sec Seclions 413.3.5 and 413.4. 7. DUCT is a conduit (plain or corrugated) to accommodate prestressing steel for post-tensioned install ation. Requirements for post-tensioning ducts are given in Section 418.18. EFFECTIVE DEPTH OF SECTION (d) is the di slance measu red from ex.treme compression fiber to centroid of tension reinforcement. EFFECTIVE PIlESTRESS is Ihe Slress remai ning in prestressing tendons after all losses have occu rred. excluding effects of dead load ilnd superimposed load. EMBEDM ENT LENGTH is Ihe lengl h of embedded reinforcement provided beyond a critical section. EQUILlUIlIUM DENSITY is th e density of li ghtweiglH concrete after exposure 10 a relmi ve humidit y of 50 ± 5 percent and a tempera ture of 2].00 ± 2.(X)O C for a period of lime sufficient to reac h cons tant de nsity (see ASTM C567).
11 National Structural Codo of ti le Philippines 6 \ Edition Volum e 1
4-10
CHAPTER 4 - Concrete
EXTREME TENSION STEEL is the reinforcement (prestressed or nonpre.'itrcssed) that is the fm1hesl from the extreme compression fiber.
MODULUS 01' ELASTICITY is Ihe ratio of normal .
HEADEJ) DEFORMED BARS are deformed reinforcing
MOMENT FRAME is a fr.amc in which
bars with heads att,lehed at one or both ends. I-leads arc attached to fhe bar end by means such as welding or forging
joints res ist forces through Jlcxure, shear, and axial force. Moment framcs designated as pan of the scismic·for cc~ resis ting system sha ll be categorized as follows:
onto the bar, int ernal threads on the hend mating
[0
threads
on the bar end, or a separate threaded nut to secure the head of the bar. The Ilet bealing area of headed dcfonnt'd bar equals the gross area of the head minus th e larger of Iht, arC:l of the bar and the area of any obstructioll. HEADED SHEAR STUD REINPORCEMENT is a reinforcement consisting of individual headed studs. or groups of studs. wi th anchorage provided by a head at each end or a common base rail consisting of a stee l plate. or shape_
HOOP is a closed ti e or cOOli nuously wou nd tie . A closed tie can be made up o f severa l reinforcement clements each having hooks at both ends. A continuous ly wound tic shall have a seismic hook at bolll ends. See Sectio n 42 1.
and
ORDINARY MOMENT FRAME is a c'lSl-in -pl,,;· ... " precast concrete frame complying with Ihe requirCl1l1..'.ilt:·: i iI' Sections 401 to 418, and, ill the case of ordinary mOI!:" : ~ l rrames assigned 10 areas with low seis mi c ri sk. :d:-"'_.I c:o mplying with Section 421 . 14. INTERMEDIATE MOMENT PRAME is a cast- in-place frame complying with the requi remeIHs of Section 421.12 II! addilion to the requirements for ordinary moment frrlmes.
ISOLATION JOINT is a separati on bel ween adjoining
SPECIAL MOM ENT PRAME a cast- ill-plaee fra me complying wit h the requi rements of Seclian 42 1.3 .4 thrOllp i: 42 1.3.7, 42 !.5 through 421. 7, or a precast fraille complyi lfg with the requirements of Sectio n 421.5 through 421. ;; . 42 J • J 3.1 through 421 . 13.4. Jn addition, the requireme nts L ordinary momen! frames shall be satisfied.
parts of a concrete structure, usually a vertical plane. at a designed location such as to interfere least with performance of the structure, yet such as to all ow relative movement in three directions and avoid fonnation of cracks elsewhere in
NET TENSILE STRAIN is the lensile sirain at Ilomin;': strength exclusive of st rains due to effective prestres :~> creep. shrinkage and Icmperilwfc.
the concrete and through which all or pan of the bonded reinforcement is inten·upted .
JACKING FORCE is Ihe lemporary force exerted by device that introduces tension into prestressing tendons in prestressed concrete. JOINT is tI pan ion of struct ure common to intersec ting members. The effect ive cross-seclionnl area of a joint of a special momcnt frame, AI. for shear strength comp utalions is defined in Seclion 421_7.4.1. LOAD, DEAD is the dead weight sllpponed by a member. as defined by Section 204 (without load factors).
LOAD, FACTOn g J) i:-) the load, multiplied by ilppropr i
PEDESTAL is an Upri glH co mpression member with a rmin of unsupponed heigh! to average least lateral dimcnsion nol cxceeding 3. For a tapered member, the lensl lateral dimension is Ihe average of the top und ho ttom dimensions of the smalier side. PLAIN CONCRETE is !-;trllctura l concrete with Ih"1 reinforcement or with less reinforcement {han Ihe minimlHil amouill specilied for reinforccd concrctc. PLAIN REINFORCEMENT is reinforceme lll Lhal doc·; not co nform to definition of deformed reinforceme n!. Sec Section 401.6.4. PLASTIC HING E REGION is Ihe Iellgl h of fra ll;;dement over whi ch Il cx ural yielding is intended to OCCli l d u t.~ to canh quakc design displac.:mcnts, cxte nding not less than a distance. II from the c:rilic:al !-;cclioll where ncxlInll yiel ding i nitiatc!-;. Sec Section 421 . POST-TENS IONING is il method of prestressing ill which Icndolls
pnECAST CONCRETE is a strucltlral COIKl"el C elemelll <.:;Isl in othe r than ils final position in Ihe slruclurc.
Association of Structural Engineers of the Philippines
CHAPTER 4 . Concrete
pRJECmilPIU;SS;ED TENSILE ZONE is that pOI1ion of
member where flexural tension, calculated section properties, would occur under dC
concrete, to provide corrosion protection, and corrosion inhibiting coating.
to
4· 11
contain the
grosS
SHORES arc vertical or incli ned suppon members des igned to ca rry the weight of the forrnwork, concrete and constl1lclion loads above.
CONCRETE is stl1JclUral concrete ill : which internal stresses have bee n int roduced to redu ce
SPAN LENGTH . See Secti on 408. 10.
' po!entli'''! tensil e stresses ill concrete res ulting from loads.
J'RESTRESSING STEgr, is
l\
hi gh-strength Sh::cJ cl em e nt
stich as wire. bar, or :-trand, Of a hundlc o f such cle men ts,
used to impart prcstrc,,, forces to t:oncrclc. PRETENSIONJNG
IS
SPECIAL' ANCHOHAGE DEVICE is an anchorage device thai satisfi es Section 4 18. 16. 1 and the standardi zed acceptance tests of AAS HTO "Standa rd Specifications for Highway Bridg{!s ", 17" Editioll, 2002, Division II, Section 10.3.2.3.
a method of prestressin g in wh ich
tendons arc tensioned be fore co ncrete is pl a(;ed.
REINFORCED CONCRETE is st rllctural concrete reinforced with 110 less tlum the mini mum amounts of prestressin g tendons or non prcslrcsscd rein force men t specified ill this chap ter.
SPECIAL BOUNDARY ELEMENT is a boundary clement required by Sec tions 421 ,8,6.2 or 42 1.8.6.3. SPIRAL REINFORCEMENT is contin uously wound reinforcement in Ihe foml of a cylindri cal heli x. SPLITTING TENSILE STRENGTH
REINFORCEMENT is mate ri al th"lt conform s to Section 403,6, exclud ing prestressin g ten dons unl ess specificall y included.
(f;,) is the tensi le
slrength of concrete delerm ined in accordance with ASTM C496M as described ill "Specificatiolls for Ught weight Aggregar{! for Structural Con crete " (ASTM C330). See Section 405.2.4.
RESHORES arc sho res pl aced sllu g l y under a CO IKTC iC slab or othe r stfuclUfal member after the original fo rms and
STEEL FIBER·REINFORCED CONCRETE. Conc rete
shores have been re moved rrom a large r area, thus req u iring
containing dispersed rando ml y oriented steel fi bers .
the new slab or s[nIctural mcmber to deflect and support its own weight and existing construction loads applied pri or to fh e installat ion of the res hores. SEISMIC DESIGN CATEGOHY is a cl ass ification assigned to a stru cture based on it s occ upancy t:tl lcgo ry and the severit y or the design earthquake ground motion at th e site. as defin ed hy the lega ll y adoptcd ge ncral building code.
STIRUUP is reinforcement used to resist shear and torsion stresses in a Slillctural me mber; typicall y bars, wires, or welded wire fabri c (plain or defonned) bent into L, U or
rectan gular shapes and located perpendi cul ar
10
or at an
also "Tie."
SEISMIC·FORCE·RESISTING SYSTEM is a portion of the struclUrc designed to res ist earthq uake design forces
required by th e legall y adopted general buildin g code using the applicable provisions and load combinations.
SEISMIC HOOK is a hoo k on a stirrup. or crosstie ha ving a bend not less th an 135 degrees, exce pt thaI circula r hoops Shall have a bend nor less than 90 degrees. I-Itx)ks shall have a 6dv, but not less than 75 mm extellsion tha t engages the longitUd inal reinforceme nt and pruje<.:ts into the interior of the stirru p or hoop. Sec Section 407.2.4 and Section 42 1.2. SHEAR CAP is a projec t below the slab used In increase
the sl:! h she;lr strength . See Secti on 4 1J.3.6. SHEATHING is a malcri:!1 cncas ing a prestressing tl~!l(l on to prevent bonding the tendon with the surroullding
STRENGTH, DESIGN is the no minal strength multiplied by a st rength -reducti on factor, ¢. See Secti on 409.4 . STnENGTH, NOMINAL is the stren gth o f a memb er o r cross secti on calcula ted in accordance with provisions and assumptions of thc strc ngth design mcthod of thi s chaptcr
before appl ication
or
any strengl h~reduct ion factors . See
Section 409.4. 1. STRENGTH, REQUIRED is the strength of " member or
cross secti on required to resi st factored loads or reltltcd internal moments and forces ill stich combinations :IS arc stipul
STRESS is the intensi ty of force per unit arCl!.
1h
Nationa l Structural Coclo of the Plli!ippirw s 6 Edition Volume 1
4 -12
CHAPTE11 4 - Concrete
STRUCTURAL CONCRETE is all concrete used for s tructural purposes , including plain and reinforced conc rete. STRUCTURAL DIAPHRAGM is a structural member, such as a fl oor or roof slab, th at transmits forces acting ill the plane of the member to Ihe vertica l elements of the seismic-force-resis ti ng syste m. See Secti oll 42J for requirements in the earthquake-resisting structures. STRUCTURAL TRUSS is an assemb lage of reinforced concrete members subjected primarily to ax ial forces. STRUCTURAL WALL is a wa ll propoJ1ioned to resi st combinations of shears, moments, and axial forces. A shear wall is a structural wall. A structural wall designated as part of Ihe seismic-force-resisting system shall be categorized as fo ll ows:
.
,
II
I
ORDINARY STRUCTURAL PLAIN CONCRETE WALL is a wall complying with the requirements of Section 422. ORDINARY REINFORCED CONCRETE STRUCTURAL WALL is a wall co mplying with the req uirement s of Secti ons 401 through 4 J 8. INTERMEDIATE PRECAST STRUCTURAL WALL is a waJl complying with all app licable requirements of Sections 40 1 through 41 8 in addition to 42 1. SPECIAL STRUCTURAL WALL is a cast-in-place or precast wa ll shall comply with the requirements of Sections 421.3.3 through 421.3.7, 421.8 and 421.15 as app licable, in addition to the requirements ror ordinary reinforced concrete stnlclUral w'llls.
TRANSFER LENGTH is [he length of embedded pretensionedstrand rcquired to transfer the effective prestress to (he concrete. UN BONDED TENDON is tendon in whi ch the prestressing steel is prevented from bonding to (he l:oiic retc and is free 10 move relative to the concrete. The prestressing force is pcnnanently transferred to the concrete al the tendon ends by anc horage only.
WALL is a member, usually vertical, IIsed to enclose or separate spaces. WELDED WIRE REINFOR CEMENTS are rei nf(.rcing elements consisting of ca rbon-steel plain or defo rmed Wires, confo rming to ASTM A82 or A496, respectively, fabrica ted int o sheets 0 1' rolls in accordance with ASTM A 185 or A497M, respectively; or reinforci ng elements consisti ng of stainless-steel plain or deformed wires fab ricated into sheets or roll s conformi ng to ASTM A I 022. 'W OBBLE FRICTION in prestressed co ncrete is I'!iction caused by unintended deviation of prestressi ng sheath or duct from its specified profile.
\\fORK is the entire co nstlllclion or separately identifiable pans Ihereof that are requi red to be fUl1lished under the contract documents. YIELD STRENGTH is the specified minimum yie ld strength or yield point of reinforcemenl in MP a. Yield strength or yield point shall be determ ined ill tension accord ing to appli cable ASTM standards as modified by Section 403.6 of this code. :,,: .
TENDON. In pretcllsioned app lications. the tendon is the pres tressin g steel. In pos t-tensi oned appli cations, the tendon is a complete assembly consisti ng of. anc horages, prestressi ng steel. and shea ting with coating ror unbounded applications or duc ts with grout fo r bonded applications. TENSION-CONTROLLED SECTION is a cross section in which th e Ilet tensile strain ill the extreme tension steel at nom inal strengt h is greate r than or equal [ 0 O.(XJ5.
TIE is
T1lANSFEIt is the ac t of transferri ng stress in prestressing tcndons from jads or prctcnsioning bed to (;Oilcrett! me mber.
Association of Structural Enqineeni of tlln
Ph l hrpUlf:~
~.
CHAPTER 4 - Concrete
4-13
403.4 Aggregates
403.4.1 Concrete aggregates shall conform to one of the rollowing specifications: "SpecijicmiollsJor Concrete Aggregares" (ASTM C 33):
= specified
yield ""ength of non prestressed reinforcement, MPa ::: nomin al diameter of bar, wire, or prestressing strand,
"SpecijicariollS Jar Lighrweighr Aggregates for Srl"Ucrurai COllcme" (ASTM C 330).
Aggregates failing (0 ' meel the above specifications but which have been shown by special tcsL or aC{lJal service (0 produce concrete of adequate s trength and durability ma y be used where authoriz.ed by the engineer-of-rccord.
mill
Tests of Materials TIle engineer may require the testing of any 'materialS used in concrete constnJctioll to determine if malerla" are of quality speci fied. Tests of materials and of concrete s hall be made in ' ac,cordal1ce with the standards listed in Section 403 .9.
403.2.3 Complete record of tests of Illmclials and of ; concrete shall be available for inspect iOIl durin g prog ress of , work and for two (2) years after COJllph~ lion of [he project, · br as required by the implementing agency and shall be · preserved by the engineer for that purpose.
403.4.2 The nominal maximum size of coarse aggregate shall not be larger than: I.
One fifth (1/5) the narrowest dimension between sides of rOfln s; or
2.
One third (113) the depth of slabs: or
3.
Three fourth s (3/4) Ihe minimum clear spaci ng between . individual reinforci ng bars or wires, bundl es of bars, or prestressing tendons or dUClS.
These limitations may be waived if, in the judgmcm of the engineer, workability and methods of consolidation are sllch thal concrete can be placed without honeycomb or voids.
· 403.3 Cement ; 403.3.1 Cement shall con form
10
one of the following
"Specifications/or Pon/wu/ Cement" (ASTM CI50). "Specifications for Blended Hydraulic Celllellls" (ASTM C 595M), excluding Types S and SA which arc not intended as principal ceme nting constituents of structural conc rete. "Specifications for Expollsil'e Hydraulic Cel11e"," (ASTM
C 845). Fly ash and natural pozzolan: ASTM C618. Groulld-granulmed blast-I"uflwcc s lag: ASTM C989.
403.5 Wat er 403.5.1 Wilter used in mixing conc rete shall be clean and free from injuriolls amounts of oils, acids, alkalis, sa lts, organic materials or other substances deleteri ous to concrete or reinforcement.
403.5.2 Mixing water fo r prestresscd concrete or for concrete that will corllain aluminum embedments, including that portion of mi xing water contributed in the form of free moisture 011 aggregates, shall not con tain deleterious amounts of ch loride ions. See Section 404.6. I . 403.5.3 NOIl-p0lable waler shall not be lIsed in concrete unless the rollowing :lfe satisfied : 403.5.3.1 Seleclion of concrele prnp0l1 ioils shall be
Silica fume: ASTM C!.'40.
ba~ed
on co ncrete mixes using w
403.3.2 Cement used in th e work shall correspond to (hat on which selection of COllnc (c proporti ons was based . See Section 405.3 .
403.5.3.2 Mortar tc st cubes made with nonpowblc mi xing water shall have 7-day and 28-day strengths equal to a( k:ast 90 percent of strcngths of similar specimens made with pmablc water. Strength test co mparison shall be Il1tlde on 11l0l1ars, identical except for lhe mixing waler, prepared il nd
Nationa l Structural Code of th e Pll i1ippines G(I\ Edition Volume 1
."
4·14
CHAPTER 4· Concrete
tested in accordance with "Tesl Method for Compressive Strength of Hydraulic Cement Mortars (using 50-nun Cube Specimens)" (ASTM C 109).
Concrete Reinforcement" (ASTM A 496M). exccpt that wire shall not be smaller than size MD25 or larg'·' ii ·i i \i .' i ~ MD200 unless as permitted in Section 403.6 .. h " '" with a specified yield streilgth /y exceeding . ,'~ i:j lvi r'a, /;. shall be the stress corresponding to a strain of 0 ..,) ptrC(llt.
403.6 Steel Reinforcement 403.6.1 Reinforcement shall be deformed reinforcement, except that plain reinforcement sh:lll be permitted for spirals or prestressing steels; and reil;iorcement consisting of headed shear studs, structural steel, steel pipe or steel tubing shall be permitted only for resisting shear under conditions specified in Section 411.6.6.1(6). 403.6.2 Welding of reinforcing bars shall conform to "Structural Welding Code - Reinforcing Steel", ANSIIAWS DIA of the American Welding Society. Type and location of welded splices and other required welding of reinforcing bars shall be indicated on the design drawings or in the project specifications. ASTM reinforcing bar specifications, except for ASTM A 706M, shall be supplemented to require a report of material properties necessary to conform to requirements in ANSI! AWS D1.4. 403.6.3 Deformed Reinforcements 403.6.3.1 Deformed reinforcing bars shall conform to one of
the following specifications, except as pennitted by Section 403.6.3.3: 1.
"Specifications for Deformed and Pia ill Billet-Steel Bars for Concrete Reinforcement" (ASTM A 615M)
for seismic resisting members. 2.
"Specifications for Low-Alloy Steel Deformed Bars for Concrete Reinforcement" (ASTM A 706M) for
members resisting earthquake induced forces . 403.6.3.2 Deformed reinforcing bars shall conform to one of the ASTM specifications listed in Section 403.6.3.1 , except that for bars with/y exceeding 415 MPa,/y shall be taken as the stress corresponding to a strain of 0.35 percent. See Section 409.5. 403.6.3.3 Deformed reinforcing bars conforming to ASTM AI035 shaH be permitted to be used as transverse
reinforcement in Section 421.6.4 or spiral reinforcement ill Section 410.10.3. 403.6.3.4 Bar mats for concrete reinforcement shall conform to "5jJecijicatiollS for Fabricated D(formed Steel Bar Mats for COllcrete Reillforcemellt" (ASTM A 184M). Reinforcing bars used in bar mats shall conform to one of
the specifications listed in Section 403.6.3.1. 403.6.3.5 Deformed wire for concrete reinforcement shall conform to "Specificatiolls for Steel Wire , Dtjomzed, for
403.6.3.6 Welded
plain wire fabric for concrete reinforcement shall conform to "Specijicalio!/.I· /H )'teel
Welded Wire, Fabric, Plain for Concrete Reinfo/"u· , iOll" (ASTM A 185M), except that for wire with a ' Id strength fy exceeding 415 MPa, 1,. shall be taken :i\ iIC
stress corresponding to a strain of 0.35 percen!. \Vc-J.:1ed intersections shall not be spaced farther apart j i'; ':1 ~(jn ' . :'1 ) in direction of calculated stress, except for ",ii; 'K ,i as stirrups in accordance with Section 412.14.2. deformed wire fabric I'OJ COllecte reinforcement shall confonn to "Specifications for .; ('({
403.6.3.7 Welded
Welded Wire Fabric, Deformed, fo ,("on , .rf'-{(~ Reinforcement" (ASTM A 497M), except lhal for wire with a specified yield strength fy exceeding i~)5 MPa, .r;. shall be the stress corresponding to a strain of" (LIS pt.TccnL Welded intersections shall not be spaced faIlli, ' ~q!, ! n ; ,an
400 mm in direction of calculated stress, eX I ' T · (01 ·e fabric used as stirrups in accordance with SeCl I');) " .". " Deformed wire larger than MD200 is 'penllitt';';j w li::;] in welded wire reinforcement conforming :0 /\,' . A497M, but shall be treated as plain wire for de vtlnplJlC lJ1. and splice design. 403.6.3.8 Galvanized reinforcing bars shaU comply wi(\t "Specifications for Zinc"Coated (Galvanized) Steel!Jol.\·.{ il Concrete Reinforcement" (ASTM A 767M) . Epoxy··coal ed reinforcing bars shall comply with "Specification ior Epoxy~Coated Reinforcing Steel Bars" (ASTfd A 77.'>1/:' () J with "Specifications for Epoxy-Coated Prefabli(,·j!i'o' ci Reinforcing Bars" (ASTM A 934M). Galvanii:ed (II c,
coated reinforcement shall conform to specifications listed in Section 403.6.3. I .
01;('
403.6.3.9 Epoxy-coated wires and welded wire fal ;) Ii comply with "Srandard Specification for LI)()xy· ("//i : C( " Steel Wire and Welded Wire Fabric for Rei'!f(!/"{"( .'!; (ASTM A 884M). Epoxy-coated wires shall ",,, I,' Section 403.6.3.5 and epoxy-coated welded wile i (illl; conform to Section 403.6.3.5 or 403.6.3.6.
II<
403.6.3.10 Deformed stainless-steel wire. and deformed ;;:id plain stainless-steel welded wire for concrete I"cinf01n· l: lit shall conform to ASTM l022M, except deformed wire .',i; 'll!
not be smaller than size MD25 or larger t1' . .. ~ and the yield strength for wire with Iv eXC l"\'; ill' shall be taken as the stress correspond(ng to a s{rall! 01 U .j) percent. Deformed wire larger than MD200 is PCI i' :: : (d where used in welded wire reinforcement confo!"lllilig to
Association of Structural Engineers of the Philippines
CHAPTER 4 . Concrete
i
ASTM AI022M. but sha ll be o'eated as plain wire for ' development and splice design. Spacing of welded
: inte.",;.;ctions shall not exceed 300 mm for plain welded wire :: and 400 mm for deformed welded wire in direction of ~ caJculntcd stress, except for welded wire reinforcement used '; as stirrups in accQrdance with Section 412.14.2.
Section 410./7.7 or 410.17.8. shall confolln to one of the following specifications: I.
"Specifications for Carbon Sree/" (ASTM A 36M).
2.
"Specifications for Hi gh-Strenglh Low-All oy Stilletural Steel" (ASTM A 242M).
3.
"Specificafiolls Jor High -Strength Low-Alloy Columbium- Vanadium Sleds of Structural Quality" (ASTM A 512M) .
4.
"Specificatiolls for ihiJ,-Slrength Low-Allo), Slruclural Sleel " with 345 MPa (ASTM A 588M).
5.
"Specifications A992M).
403.6.4 Plain Reinforcement . . 403.6.4.1 Plain bars for s piral reinforcement shall conform to one of the following specification: ASTM A615M or A706M . 403.6.4.2 Plain wire for spi ral reinforcement shall confonn to "Specifications f or Steel Wire. Plain, for Concrete Reinjorcemem" (ASTM A 82M), except Ihal for wire wilh a specified yield strength!, exceeding 415 MPa./, shall be the stress corresponding to a strain of 0.35 percent.
403.6.5 Headed Shear Stud Reinforcement 403.6.5.1 Headed studs and headed stud assembl ies shall confonn to ASTM AI044M .
shall
l.
Wire conforming to "Specifications for Uncomed Stress-Relieved Steel Wire for Prestressed Con crete " (ASTM A 42 1M).
2.
Low-re la xati on wire cOllformin g 10 "SjJecijicoliolls for Uncoated Stress- Relieved SU'e/ Wire for Prestressed Concr ete " including Su pplemcill "Lt) w-Reiaxarioll Wire " (ASTM A 421 M)
3.
Strand conforming (0 "SpecificmiollS for Steel Stn/fld, Un COaTed Seven- Wire for Prestressed COl/ crete " (ASTM A416M).
4.
Bar conforming to "Specijicllliolls fo r Uncoated HighStrength Steel Bar Jor Prestressing Conc rete " (ASTM A 122M)
403.6.6.2 Wire, strands , and bars not specifically listed in ASTM A 4 16M . A 421M alld A 122M arc allowed. provided they con form to minimum requirements or Ihesc spccifications and do not have prOI)Cl1ics that make thcm less satisractory (han those listed in these s pecificati ons. 403.6.7 Structural Steel, Steel Pipe or Tubing 403.6.7.J Stmctur
for
SIrucfIlral
,~hllpeJ"
(ASTM
403.6.7.2 Steel pi pe or tubin g fo r composite compress ion members composed of a steel -encased concrete core meeting requirements of Section 410.17.6 shall conform to one of the following specifications: J.
Grade B of "Specifications for Pipe, Steel. Black and Hot-Dipped, Zinc-Coaled Welded alld Seamless" (ASTM A 53M).
2.
"Specifica tions for Cold-Formed Welded and Seamless Carbon Steel Structural Tllbing ill Rounds and Shapes" (ASTM A SOOM) .
3.
"Specijications Jo r flor-Formed Welded alld Seamless Carboll Sleel Tllbillg" (ASTM A 50 1M).
403.6.6 Prestressing Tendons 403.6.6.1Tendons for prestressed reinforcement confoml to one of the foll ow in g speci fi cati ons :
4-15
403.6.8 Steei discon tinuou s fiber reinforcement fo r concrete shall be deformed alld conform to ASTM A820M. Steel fibers have a lell gl lHo~diameter ratio not smaller than 50 and not grealcr than 100. 403.6.9 Headed defo rmed bars shall co nform to ASTM A970M and obsll1lclions or interruption s o f th e bar defonnati ons. if any. shall not extend Illorc lhan 2th rrom the bearing face or the head.
403.7 Admixtures 403.7.1 Admixtures fo r water reduction and setting time modification shall co nform ASTM C494M . Admixtures for usc in producing nowing concrete shall conform ASTM C IOI7M. 403.1.2 Air-entrain ing admixlUrcs shall conform to "Specificmio flslor Air-EllIrai"inlj Admixtures fur CO/l crete" (ASTM C 260). 403.7.3 Admixtures to be used in conc rete lhat do 110t conforl1l lO Sections 403.7.I .ilnd 403.7.2 s ha ll be subject to prior approval by the engineer.
Nationa l Structural Code of the Pl1ilippine s Sill Edition Volume 1
4·16
CHAPTER 4 . Concrete
403.7.4 Calcium chloride or admixtures containing chloride from other than impurities from admixture ingredients shall not be used in prestressed concrete, in concrete containing embedded aluminum, or in concrete cast against stay-inplace galvanized steel forms. See Sections 404.6.1 and 406.3.2. 403.7.5 Fly ash or other pozzolans used as admixtures shall conform to "Specificalions/or Fly Ash and Raw or Calcined Natural Pozzo/an for Use as a Mineral Admixture in POri/and Cement Concrete" (ASTM C 618),
403.7.6 Ground granulated blast-furnace slag used as an admixture shall conform to "Specifications for Ground Granufoted Blast-fumace Slag for Use in Concrete and Mortars" (ASTM C 989).
403.7.7 Admixtures used in concrete containing ASTM C845 expimsive cements shall be compatible with the cement and produce no deleterious effects.
403.7.8 Silica fume used as an admixture shall conform to
A185/A185·07 Standard Specifications for Steel Welded Wire Fabric, Plain, for Concrete Reinforcement A242/A242M·04a Standard Specifications Strength Low~Alloy StructuraL Steel
for
A307/A307~07a Standard Specijication for Steel Bolts and Studs, 415 MPa Tensile Strength.
High.
Carbon
A416/A416M·()(; Standard Specificatiolls for SIal Slrand, Uncoated Seven~Wirefor Prestressed Concrete A42J/A421~05 Stress~Relieved
Standard Specifications for Uncoated Steel Wire for Prestressed Concrete
A496/A496·07 Srandard Specificatians for Steel Wire, Deformed, jar Concrete Reinforcement A497/A497·07 Standard Specifications for Steel Welded Wire Fabric, Deformed, for Concrete Reinforcement
"Specificatioll for Silica Fume for Use in Hydraulic-Cement Concrete and Mortar" (ASTM C 1240).
ASOO/ASOO·07 Standard Specifications for Cold·Formed Welded and Seamless Carbon Steel Structural Tubing in Rounds and Shapes
403.8 Storage of Materials
A50 II A50 1-07 Standard Specifications jor fiat-Formed Welded and Seamless Carboll Steel Structural Tubing
403.8.1 Ccmentitious materials and aggregate shall be stored in such manner as to prevent deterioration or intrusion of foreign Imitter.
403.8.2 Any material that has deteriorated or has been contaminated shal! not be used for concrete.
A5721 AS72·07 Standard Specifications Low-Alloy Columbium- Vanadium Steels StT'(~Jlgth
for High· Structural
AS88/A588M~OS Standard Specifications for High.s'trength Low-ALloy Structural .)'teel up to 345 MPa minimum yield point with Atmospheric Corrosion
403.9 Standards Cited in this Chapter
Resis{(~llce
403.9.1 In the absence of the Philippine National Standard (PNS), Standards of the American Society for Testing and Materials (ASTM) referred to in this chapter listed below with their serial designations, including year of adoption or revision, arc declared (0 be part of this code as if fully set forth herein:
A61SIA615M-07 SWlldard Specijications for Deformed and Plain Billet-Steel Bars jor Concrete Reinforcement
A361 A36M·05 ,)'tJ'Uct/lral Steel
Standard
SpecUlcatiol1S
for
Carboll
A . 531 A53 .. 07
Standard SpeClficatiolls for Pipe, Sted, Black and lim-Dipped, Zinc-Coated Welded (Ind Seamkss
A 706/A 706M-06a Standard Specifications for Low-Alloy Steel Deformed Barsfor Concrete Reinforcemelll A 7221 A 722-07 Standa,.d Sp(~cifica(ions for UnCOOfu/ High-Strength Steel Bar/or P}'(~stressillg Concrete A 76 7I A 767M ~OS Statu/ard S/J£'cificatiolls for Zi,u -Coaled (Galvanized) Steel Barsfor COil crete Reinjoram('J/t
A775/A77SM-07 Standard A821 AB2-07 Standard Spec!fications for Steel Wire, Plain, for Concrcte Reit(forcemelll A 1841 AI 84-06
Standard 5'pec(ficatiolls for Fabricated Dljonlled S'rcel Bar Mats/or COJJcrete ReiJ!forcement
Coat(~d
SpecificatioJls
for
Ejwxy-
Reilljorcint: Slee/ Bars
A8201 A820M··06 Swndard SpecificalioJ1s for ,S'teei Fiber' for Fiber Reinforced CO!lcrde
ASSOCIation of Structural Engineers of tile Philippines
CHAPTER 4 . Concroie
Specifications for EpoxyWelded Wire Fabric for
A884/A884M-06 Standard . Coated Steel Wire and
S'pecifications for
4·17
Port/and
CISO-OS Cement
Standard
CI72-04 Mixed Concrete
Standard Method of Sampling Freshly
Reinforcement A934/A934M-07 Standard Specifications Coated Prefabricated Steel Reinforcing Bars
for
Epoxy-
. A955/A9SSM-07a Standard Specifications for Deformed
and
Plain
and
Stainless
Steel
Bars for
CI92/CI92M-06 Standard Method of Sampling Freshly Mixed Concrete
Concrete C231-04 Standard Method for Air COfltenl of Freshly Mixed Concrete by the Pressure Me/hod
Reinjorcemellf A970/A970M-06 Stondard Specifications for Headed Steel
Bars/or Concrete Reinforcement
C260-06 Standard SpeCificaTions Entraining Admixtures for Concrere "
A9921A992M-06a Standard Specifications for Structural Steel Shapes A996/A996M-06a Standard Specifications for
and Axle Sleel Reinforcement
Deformed
Bars
for
for
Air-
C330-0S Stondard Specifications for Lightweight Aggregatesfor Structural Concrete
Rail-Steel
Concrete
A!0221AI022M-07 Standard Specification for Deformed and Plain Stainless Sleel Wire and Welded Wire for
C494/C494M-OSa Standard Specifications for Admixtures for Concrete
Cltemical
C496/C496M-04 Standard Test Metltod for Splitting Tensile Strength of Cylindrical Concn:te SpeCimens
Concrete Reinforcement AI03SIAI03SM-07 Standard Specification for
Deformed
C567-05a Standard Test Method for UniT Weight of Structural LighTweight Concrete
and Plain, Low-Carbon, Chromium, Sleel Ban'for Concrete Reinforcement
Standard CS9SM-07 Hydraulic Cements
Specifications
for
Blended
AI044/AI044M-OS Standard Specification for Steel Stud
Assemblies/or Shear Reinforcement of ConerNe C291C29M-03 Stondard Method for Bulk Demity (Unit Weigh!) and Voids in Aggregare
C618-05 Standard Specifications for Fly Ash and Raw or Calcined Natura! Pozzohm for Use as a Mineral Admixture on Portland Cemenf Concrete
and
C685/C685M-O I Sralldard Spccificaliolls for ConcrelC Made by VO!llIllNric Barching and Confinuous Mixing
Concrete
Standard Spec((ications for expansive C84S-04 Hydraulic Cement
C39/C39M-05 Standard Test Method for Compressive Strength of L)lilldrical Concrete Specimens
C989~06 Standard Specifications for Ground Granulated BIaSI-Furnace Slag for Use in Concrete and Morlars
C42/C42M-04 Standard M(~lhod of Obtaining Testing Drilled Cores and Sawed Beams of Concrete
C!OI2-04 Tes! Method for Length Chang(~ l1)Ylraulic-Cement Mortars Exposf.>d {() a Su~(a!e ,)'olurioll
C31/C31 M-06 S'randard Practice f6r Making Curing COl/crete Test Specimens in the Field
C33-03 Aggregate
Standard
SpeCifications
for
and
(4
S'tal1(/ard ,S'pec({icarions for Ready-Mixed
C lO I7/C J 0 J 7M-OJ Slandard Specifications for t:hemica! Admixluresfor Use in Producing F/owinx Concrele
Cl 09/C! 09M-05 Standard Tcst Merhod for Compressive Strength (~( Hydraulic Cemenr Mortars (Using 50-mill Cub(~ Specimens)
C I J J 6-06/C 1116M~06 Standard SpeCifications for Fiher-
C'J.1IC94M-06 Concrete
C144-04 ,\'wlldard ";pecUicatiol1s for Ar:grer:of(' for Masonry Morrar
Reinforced Concrete Slwu/ard C1157-03 (or lIwlrall./ic Cemenr
th
National Structural Code of the Philippllws 6 Edition Volume "\
Pel/tmJl(/!/c('
Seec({tc(lrions
4·18
CHAP TEI14 · Concrete
C 12 18/CI2 18M -99 Srandard Test Method for Soluble Chloride if! Mortar (1m/ Concrete
Warer
C 1240·05 Standard Specifications for Silicll f ume for Use in l1ydmulic:·Cemel1l Concrete alld Mortar
C 1602/C 1602M-()6 Srandard Spcdjications fo r Mixing War er used ill th e Production oj Hydraulic C£!lnent
404.1 Notat ion
r.·
= specifi ed compressive strength o f co ncrete, MPa. w/e m = maximum watcr-ee mel11iti ous materi al ratio ,
ConcreTe CIr,09lC I609M-06 SUmdard Test Method fo r Flexural Performallce of Fiber- Reinforced Concrete (Using Beom With Third-Poilll Loading)
403.9.2. "STructural Welding Code - Reillforcing Steel" (ANS I/A W S DI.4/D I.4M :2oo5) of Ihe American Welding Society is declared part of this code as if fully scI fo rth here in.
403:9.3 Sec ti on 203.3 Comb inin g Loads Us in g Strength DeSIgn. or Load and ResisTance Fac lor Design of thi s code as if fully sc I forth herein, for the purposes cited in Sectio ns 409.3.3 a nd 426. 403.9.4 "Spec ification Jor Unhol/ded S ingle Strand 1'e fldoll Marer;,,/'- (AC I 423.7·07)" is decl ared to be pan of this Code as if fully se t fo nh herein.
403.9.5 Seclions 9.21.7. 2 and 9.2 1.7.3 of Divisio n I a nd Secli on 10.0. 2.3 of Di vis io n II of AA SHTO "SllIlIdard Specification for Highway Bridges" (AASHTO I t" Ed iti on, 2002) arc declared to be pan of Ih is code as if fully SCI fonh herein for the purpose ci ted in Section 418.16. 1.
403.9.6 "Qualfficatiol/ of Post-h'.wafh!(1 M edulll ical IlI/ cllOrs in CO/lcrete ( Ael 355.2-(7) " is decl ared to be pa rt of Ih is Code as if full y sel fort h herein . fo r the purpose c ited in Sec tion 423, A nc horing (Q Concre te . 403.9.7 ··S,r/l clllral Welding Code Steel (A WS D 1.1/0 1.1 M:2006)" of the Ameri can Welding Soc ielY " decl ared ta be P;1I1 o f I h i ~ Code
404.2 Definitions Th e Secti on ad dresses th ree ex posure categories that affect th e req uirements far co nc rete to ensure adeq uate durabi lit y : Exposure Category S applies to concrete in contac t wi th so il or water contai ning deleterious amounts of wate rsolub le sulfate ions as defined in Section 404.4. J. Exposure Category P appli es to conc rete ill contact wilh water requiri ng low permeabilit y. Exposure Category C applies to reinfo rced and prestressed conc rete ex posed to conditi o ns that require addition :!! protection against corros ion of reinforcement. Severity \ ,~. exposure within each category is defined by classes W l rl i increasing nume ri cal values representin g increasingly se w n ' ex posure conditi ons. A classific ation of "0" is assign'·l· when the exposu re severity has negligib le effect or docs Il {;~ apply 10 (he s t ~c tura l membe r. Exposure Category F is subd ivided into four e xposure classes. However only Exposu re Class FO appl ies II : Phili ppine condition; Exposu re C lass F J. Exposure Clas!. F2. Exposure Class F3 do no t apply as it involve concrete exposed 10 cycles of freez ing and thaw in g, in conti nuous comaC I with lllo islU re, and whe re e xpos ure 10 deic illt. c he micals is
Exposure Class FO is assigned to co ncrete that wi ll not b~ exposed to cycles o f freeli ng a nd th a win g. Exposure Category S is subdivided into four classes:
CXPOS l!I"(.:
403.9.8 "Acceptance Criteria Jor MOIII!'II' Fmmc.\· B(I.\"('(/ Oil Srruc:lurof TexrillK (Ael 374. 1-05)" is declared to be p iHl of this Code as if fu ll y set forth he rei n.
Exposure Class SO is assigned for condi ti ons where n, · water-so lu ble sul fate concen tration in CO il tact wi th COllen.:lt: is low and injuri ous sulfate attack is not a conce rn .
403 .9.9 "Accrl'wl1cr Criferia Jor Spel."ia/ UlliJOIu/ed Pn.fr- Tt'usinl1rd Precast Strllclllr(J/ Wafl.\· Bused 011 Valida/iot! Fe.flif/g (AC T ITG-5 . 1-07) ,. is dCcJiln:d to be part of th is Code as if fu ll y SC I fo rth herei n.
EXJlosure C lasses Si t S2, and 53 arc assigned for structural concrelc members ill direct contact with solub le su lfales in soil or W.1IC r. The severity o f exposure increases frolll Expos ure Cl ass S I to S3 based on th e marc crili ciil val ue of Illc
ASSOCI(l\ IOII
of Slfl Jr:luraj Er)g inecr$ of tile Phil ippines
CHAPTER 4 . Concre le
Exposure Category P is subdivided into two expos ure classes: Exposure C lass PO SlIllcturaJ members should be assigned when there nre no speci fic penncnbility requirements.
to
Exposure Class PI is assigned all the bas is of the need for co ncrete 10 ha ve a low permeability to water when the permeation of water into concrete might reduce durability or affect the inten ded functio n of the stru ctural member. Exposure Class P I should typically be ass igned when other exposure classes do not app ly. An example is an interior wa ter tank.
Exposure Category C is subdivided into three ex posure classes:
~ - 19
404.5 Special Exposure C onditions
Concrete that will be subject to the exposure given in Table 404-2 shall confonn to the corresponding maximum watercementiti ous materi als ratios and minimum specified concrete compressive strenglh requirements o f that t:lblc. 404.6 Uequirements for Concrete Mixtures 404.6.1 Based on th e expos ure classes assigned from Table 404- 1, concrete mixtures shall comply with ti~e JIlost res trictive requirements accord ing to Table 404 ·2. '. 404.6.2 Calcium chl oride as an admi xture shall not be used in concrete to be exposed to severe or very seve re su lfate· co ntaini ng solutions, as defin ed in T able 3.1 of AC I 222R.
Exposure Class CO is assigned when exposure conditions do not require addi tional protection against the initiation of corros ion of reinforcement
404.7 Alternative Cemenlitio us Materials for Sulphate Exposure
Exposure Classes C l and C2 are assigned
404.7.1 Alternati ve combinat ions of cementitious materials to those listed in Table 404-2 shall be permitted when tested for sulfate resistance and meeting the criteri a in Table 404-
reinforced and prest ressed concrete members depend ing on the degree of exposure 10 ex ternal so urces of moisture and chlorides in se rvice. 10
Exa mples of external so urces of chlorides include concrete in direct contact with deicing chemicals, saIl, salt water, brackish water, seawater, or spra y from these sou rces. 404.3 Ge nera l 404.3 .1 The v.lue of /",. sh.1I be the greatest of the values required by Section 404.3. 1, for du rabi lit y in Section 404, and for structural strength requirement s and shall apply for
mi xt ure proponioni ng in Section 405.4 and for evaluation and (lCceplance of concrete in Secti on 405.7. Concrete mixtllres shall be proportioned 10 comply with the maxi mum watcr-ccrnen ti tious material rat io ( w/em) and other requirem ents based on the exposure class ass igned to tile concrete structural member. All cememili ous matelials fi pecified ill Secti on 403.3. 1 and the combina ti ons of these materials shall be included in calculating the w/cm of the co ncrete mixture. 404.3.2 The maximulll wlew limi{,s in Section 404 do not appl y to light weigh t concrete.
404.4 Ex pos ure C ate go ries and Classes 404.4.1 ' nlC engineer·of-record :->h<111 assig.n exposure clas:->cs based on th e scverit y of the anti cipated ex posu re of structural concrete. members for each ex posure category acco rdin g to Table 4()4- I.
3. 404.8 Water-Cemcntitious Materials Ualio
The
waler~cementiti o u s
materi als ratios specified in Tables
404- 1 and 404-2 shall be ca lcul ated using the weight of cement meeting ASTM C 150. C 59SM. C 845 or C 11 57 plus the weight of ny as h and other pozzolans meeting ASTM C 6 18, slag meeting ASTM C 989, and s ilica fu me meeti ng ASTM C 1240, if any.
404.9 Co rrosion Protection of Reinforceme nt 404.9.1 For corrosion concrete, maximum
of rc inforce ment in watc r soluble chl oride ion concentrations in hard ened co ncrete at ages from 28 to 42 days contributed from the ingredients, including water, aggregates, cementitious materi als and admixtures fihall not exceed the limits of Table 404-2. When testin g is performcd to determine water soluble chloride ion co ntent, test proced ures shall conform to AS TM C 121 8. protecti on
404.9.2 If concrete with reinforce ment will be ex posed
to
chlorides from sal\. salt water, hrackish \...lter. se
111
Natlollal Structura l Code of the Pililippin es 6 Eclition Volum e 1
CHAPTEH 4 " Concrele
Table 404" I Exposure Calegories And Classes
c0
c' c
~
>
~
B U
0
"
V>
U
--------_.
..
~.,.
_[i_
Condition
---------- -- -- -- ---- -
-
--w~-i~-~~-~ojui;!e'-·-·
.
.~------
w
N/A
'" "'
Moderate
~
.q -
0
.;:
.;
E
...
_-
"
--
(SO~) in
Titious t--~at:?!~ N/A
SO
50'1 <0.10
50.1 < 150
PI
OA5
3t
N/A
N/A
SI
0.10 ::;50.1 < 0.20
150:;;50.<1500
P2
OA5
31
N/A
N/A
F3
0.45
31
N/A
0.20::; 504 SO~
:;;
2.00
Seawater 1500:5 SO. S
10,000
504 > 10,000
> 2.00
--~--
[n contact with water where
~-~--~.-.-. "
..
Calcium
Chloride
ASTM CI157
ASTM Ct50
ASTM C595 No Type
No Type:
No
rnHiclion
n:wiClion
Re,tric~ion
N/A
17
NoT)"p¢ rewiClion
0.50
28
JJ ,
Admixture
W(MS) .
In contnc\ with wtller where permeability is not required. .
N/A
Ccmentitiou$ Materials + Types
permeability is not required .
PI ~
Ccmcn-
N/A
PO
Required
Limits on
Air Content
SI
~
---"
.....,-,,-,--Dissolved
-- 1 - - '
N/A
Additional Mil,limum Requirements
17
~:.o
"
MPa
N/A
3' .3 rl
'"n.
w/cm*
F0
S3
Severe
._ CiUIS.
water, ppm
S2
Very
Min. f..,
sulfate
V>
Severe
Max.
~ht
V> 0.
;:0
SUft
"-"
sulfate (SO.) in soil. percent by
f-
TabJc 404-2 Requirements for Concrete by Exposure Class
No
MS
IS (<70)
Restriction
(MS)
"'---
IP (11$)
S2
V,
31
0.45
No'
HS
IS «70)
I'cnnit!ed
(l1S)
~------------.---~
NtA
CO
II' (IlS) +
Concrete dry or protected from rnoistme S3
o~
0
'g
0 0
0
"E u u "
". e.S: 0
"o
/"vfooerate
CI
U ~,£
Severe __
C2
3I
pouolan or slag! or IS
Poaolan or Slag II
«70) (I1S) +
Concrete exposed to moisture and an cxtemal source of chloride from salt, brackish water, seawater, 0' spray from these sources.
HI
..
[>07.lolan or .\I~g
.-- " .~-
url..2
L
Concrele exposed to moisture but not to external sources of chloride.
0.45
V+
NIA
17
0.50
28
HS+ Pozz.o!an or Slag
Not I'cnnillcd
II
None
--PI
None WJter·",lublc jon (0-) wntem;n
Ma~;mum
<"bloride concrele. [>Crcelll by weight . __ ._~~_m."nl /I
•............".-
CO .. __.
NIA
C!
N/A
1 - ----C2 OAO
--
Related Provisions
Reinforced Concrele
I're,lre,,:.cd
17
I.{X)
0.06
17
0.30
0.06
None
0.06
Section 407.8.5, Section 418.17"
--
35
0.15
etHlCR'le
..-..
~
• Fnr /ighnw:ig/rl CQIl(rClc. sa .<:;telion 404.1.2. tA/ICI7I(lliI'( (Olllbifl(lliOIiS of (t'IIlC/l{illnIlS lIlaleria/.r of IhoJc Ii.llcd ill Table 404·2
.t/wll hc fiulllilled II"hcli Inled for .HI/fall": resislalla and 1Il(.'('Iing Ihe cdlui(l ill Sr("lioli 404.7.1. I For .{C(/\WU('t" t.I"POS"I"c. 0111<'1" IY{lI'J of porl/muf (("IIICI1/.1 willi Iric(lleium (I/ulllim/{c (C3A) (OIllI'IIH /(I! 10 10/1(,(((111 Ol"C p<,t"IIli(tcd i.llllI' II"/cm dol'S 1101 c.\"("ad 0.40.
f OlliN 1II'(li/ab/e IY{JtS of (('m,'/II .\11(11 0.1 "r:l'lIe III or 1".1'IIC / arc I!«rmill<'lf In DI{losurc Cia.l.lcs S I or S2 if Illc eM ("(ml('llis ar(' less IIIan <'I or .5 /It'f("C(II. rCS{J{'clil'l:ly. II nl(' Onlmllil (If Ih,' spccific .lOI"("C of 111<, P(!UO/(lil or s/ag /() /", uud shall Iwl be: I{'ss I/rOIi Ih" III/ifIll/II rlilli has h"fli (/('/{'Imill('d by .\en·i(c r<'(ord 10 illlflW\'(' Jill/au U'SiJIWlI."e "hell lI.t,.d ill (1lllOde (1IIlraillillg 7)p<' V all/<'liI. A/Icrn(llil·d)". Ill<' OlnoulII of 1/1<' spccific ./IllI/"(·C of Ih" po::zoiall or .>Iog 10 b(' USN! .Iha/lllOl hI' Ic$.\ Ihwi 111(' (1!1!,,11111 1".II"d ill (1("("01"<10/1("(' willi ASTM CI012 alld //l('('lillg Ihe criluia ill ,'),'(Iion
104.7./. K WOIN·.w/ulll,' chloridc illli (OIlI(,lIllhal iJ nmll"ilml('dfrom Ill(' illf.:r('diclli.t illcluding WOIN. agKI"('j:a/i·s. ("('III('IlIIliIJIlS IIIllIFfia/x. Wid ailmi.tiur('J J/w/l bc dcl('(millcd 011 Ihl' (IIII(/"('IC mixllirc by ASTM el218M (J( (/~(' "('I"'fCIl 28 (Jnd 42 d(ly.f . •• Rr
/\SSOci8tion of Structur<1i El1qincefs of t!~e Philippinos
CHAPTER 4 -Concrete
4-21
Table 404-3 Req ui rcments fo r Estobl ishi ng Suitabilit y of
Ccrncntitious Materials Combinations Exposed to Water· Soluble Su lfate
EXpOsure
Class
!
I
I
AI6 months
51
0.10 percent
S2
0.05 percenl
A I 18 monlhs
405.1 Notations
fr = specified compressive strength of concrete, MPa
Irr ; ;: required average compressive strength of concrete used as Ihe basis proportions, MPa
for
se lecti o n
of
conc rete
f.., = average splitting tensile strength of lightweight aggregate concrele, MPa
s Ss
;;;: standard deviation, MPa
= sample standard dev iat ion, MPa
405.2 General 405.2.1 Concrete shall be propol1io ned to provide an average compressive strength , fe r as prescribed in Section 405.4.2, as well as sat isfy the durability criteria of Section 404. Concrete s hall be produced to minimize frequency of strengths below Fe as prescribed in Seclion' 405.7.3.3. r:()r concrete deSigned and constru cted in accord ance with the Cod(;,
J,' shall not be less than 17 MPa. 405.2.2 Requirement s for fl' shall be based on tests o!' cyl inders made and tested as prescribed in Section 405.7.3. 405.2.3 Unless otherw ise specified,f, sha ll be based on 28day tests. If oth er than 28 days , test agc for shall be ,,' indicated in design drawings or specifications.
r,.
405.2.4 Where design criteria in Sections 408.7 .1. 412.3.4(4) . and 422.6.6. provide for use of a splilli l"
tensile strength val lie of concrete. laborato ry leS IS shall h: made in accordance with Specification for Lig/Jtweig.' Aggregates for Structural Concrete (ASTM C 330) establi sh val ue offe, correspondin g to speci fied values ofI. . 405.2.5 Splitting tensile strength tests shall not be used . , basis for field acceptance of concre tc. 405.2.6 Steel
fib c r ~ reinfoJ'ced
conc re te shall conform
ASTM C1 116. The minimu mfc' for steel fib e r-reinfo!'l concrete shall conform to 405.2.1. 405.3 Sel ection of Concrete Proportions 405.3.1 Proportions of mate rials establi shed to provide: I,
for concrete shall
be
WorkiJb ility and consistency to pe rmit co ncrete to L · worked readil y into (orms and around reinforcel),:
N<1tional Stru clur,·l l Cod(-! of thf~ PI1ilippines 6
111
Edition Volume 1
4-22
CHAlyrEFI
~
- Concrete
under conditions of placement to be employed without segregation or excessive bleeding.
Table 405-1 Modification Factor for Standard Lk'\"i;J.;ioll When Less Than 30 Tests arc Available ----------- - -.-.~---.-.----,~---~
2.
Resistance to special exposures as required by Section 404.
3.
Conformance with strength tcst requirements of Section 40S.7.
Number of Tests I
Modification
Fac[(j,:
Less than 15
Usc Table 405-2
I_~~~~~~~~~~_I Standard Dcviatio..~~_]_
...... 1
~··--------··----·-·-·-------·--·-·-I---~----
1.16
15
--~------~ - --
405.3.2 Where different materials arc to be used for different portions of proposed work, each combination shall be evaluated.
20 ----~---.---
~
30 or more 405.3.3 Concrete proportions, including w<\tcr-cementitious
1.08 - - - -- 103 1.00
materials ratio, shall be established on the basis of field experience and/or trial mixtures with materials to be
/ IllIerpo/all! Jor IIIlermedwle /lumber of lesl:.. 1 Modified slandard devialioll {() be IIsed to determine rNjllired .\·/reIJgth f" ji"O/lI Section 405.4.2.1
employed (see Section 405.4), except as permitted in Section 405.5 or required by Section 404.
405.4.2 Required Average Strength
405.4 Proportioning on the Basis of Field Experience and Trial Mixtures, or Both
-I
Ii)·,·/ .."
405.4.2.1 Required average compressive strengthfcr used
H::;
the basis for selection of concrete proportions shall be the larger of Equation (405-1) or (405-2) using the sample standard deviation, S.I' calculated in accordance with Section
405.4.1 Sample Standard Deviation
405.4.1.1 or 40S.4.1.2.
405.4.1.1 Where a concrete production facility has test records not morc than 12 months old, a sample standard deviation, SJ> shall be established. Test records from which a
F,
standard deviation
Usc the larger value computed from Eq. 405-\ and 405· :'>, or:
I.
2.
3.
.'1.11
is calculated:
Must represent materials, quality control procedures and conditions similar to those expected, and changes in materials and proportions within the test records shall not have been morc restricted than those for proposed work. Must represent concrete produced to meet a specified strength or strengths i'c within 7 MPa of that specified for proposed work. Must consist of at least 30 consecutive tests or two
groups of consecutive tests totaling at least 30 tests as defined in Section 405.7.2.4, except as provided in Section 405.4.1.2. 405.4.1.2 Where a concrete production facility docs not have test records meeting requirements of Section 405.4.1.1(3), but docs have test records [Jot more than 12 months old based on 15 to 29 consccutive tests. a standard sample deviation S" shall be established as -[Ile product of the calculatcd sample standard deviation and the
modification factor of Tahle 405-1. To be acceptable, test records shall Illeet the requircments or Section 40S.4.I.I, Items I and 2, and represent only a single record of consecutive tests that span a period of not less than 4S calendar days.
$
3SMPa:
F"
F,
-I-
(405 !)
1.34 s,
./", + 2.33 s, - 3.S
/",.>3SMPa:
t" = t, +
t"
(405-1)
1.34.1,
= 0.90 F, + 2.33
(40S-3)
.I.,
Use the larger value computed from Eq. 405-1 and 405-3. 405.4.2.2 When a concrete production facility docs not have. ficld strength test records for calculation of standard deviation meeting requirements of Section 405.4.1.1 ()'" 405.4.1.2, required average strength fu shall be dctermined from Table 405-2 and documentation of average strength shall be in accordance with requirements of Section 405.4.3.
Table 405-2 Required Average Compressive Strength When Data are not Available to Establish a Standard Deviation
Less than 21 M Pa
I,
21 '5,[, ::; 15
./', "'" g.J
/\SSOCl,:ltlon of Stn!ctuf(ll Enqll"lcers of
-I-
7.0
I. Jill', .,. S.II
tI)(~
Philippine;
CHAPTER 4 . Co ncrele
405.4.3 Documentation of A vCl'age Strength.
6.
DocumelHalion that proposed concrete proportions will produce an average compressive strength equal (0 or greater than required average comprcssive strength (see Section 405.4.2) SIHtJl consist of a lield strength test record , several strength test records, or trial mixllIrcs. 405.4.3.1 When test records in accordance with Sections 405.4.1.1 and 405.4.1.2, arc used to demonSlratc Ihat proposed co ncrete propo/lions wi ll produce the required average slrcngthf'l"l'" (see Section 405.4.2), such records shall represclllmutcrinls and conditions similar to those expected. Changes in materials, conditions and proportions within the tes t records shall not have been more restricted than th ose for proposed work. For the purpose of documenting average strength potenti
405.4.3.2 When ;.Hl acceptable record of field test results is not available, concrete proportions estab!ished from trial mixtures meeting the following restrictions shall be pcnniltcd: I.
Combination of materials shall be those for proposed work.
2.
Tria! mixtures hav ing proportions and consistencies required for proposed work shall be made using at IC
3. Trial mixtures shall be designed to produce a slump withi n ±20 mill of maximum permitted. and ror airentrained concrete, within ±O.5 percent of maximum allowable air content , or within the toleranc e !ipecified for the proposed Work . 4.
For each walcr-ccmemit iOlls mmcrials ratio or cememitiolls malcri.ds content. at Icast three tcst cylinders for each lest age shall be made a nd clIreli in accordance wilh "Method (~r Making alld Cllrilll{ COl1crele [e.I·{
SPl'Cillll'IIS ill
dw Labo/'{llory" (A STM C
192). Cylinders shall he tested at 2& d:1YS or at test age designntcd for determination ()f.r,~ 5.
From results of cyl inder tcsl.~. :l curve sl1
4·23
Maximum water-ccmentitious materials ratio or minimum cementitious matcrials conlent for concrete 10 be used in proposed work shall be that shown by the curve to produce the average strength required by Section 405.4.2, unless a lower water-ccmenlitious matcrials ratio or higher strength is required by.Section 404.
405.5 Proportion.ing without Field Experience or Trial Mixtures 405.5,1 If data required by Section 405.4 are not available, concrete proportions shall be based upon olher ex.periencc or information, if approved by the engineer. The required average compressive strength fer of concrete produced with materials similar to those proposed for use shall be at least 8.5 MPa greate r than the specified compressive strength,fl"' This alternative shall not be used for specified compressive strength greater than 35 MPa. 405.5.2 Concrete proponioned by Sect ion 405.5 shall confonn to the durability requirements of Section 404 and to com pressive st rength lest criteria of Seclion 405 .7. 405.6 Average Strength Reduction As data become available during construction, it shall be pcmliltcd to reduce the amOUrH by whi ch f l"l must exceed the specified value off ... provided: I.
Thirty or more lest results are available and average of test results exceeds th at required by Section 405.4.2 . 1.
using a sa mple standard deviation calculated in accordance with Section 405.4. 1. 1, or 2.
Fiftee n 10 29 test results arc .wailable and average of test results exceeds that required by Section 405.4.2 .1. using n sample standard deviation calculated in accordance with Seclion 405 .4. 1.2, and
3.
Spcci
405.7 Evaluation and Acceptance of Concrete 405.7.1 Concrete shall be tested in accordance with the requirements of Scction 405.7.2 through 405.7.5. Qualined field testing tech ni cians shall perform tests on fresh concrelc at the job si te, prepare specimens requircd for curi ng under fi eld conditions. prepare specimens required for testing in the laboratory. and reco rd the tempcrnturc of the fresh concrete when preparing specimens ror st rength tests. Qualified laboratory technicians shall pcrform all requircd laboratory lest') .
N('llional Structural Code o! the Pllilippin(!S GIll Edition Votl.Jlne 1
4-24
CHAPTEli 4 .- Concrete
405.7.2 Frequency of Testing
405.7.4 Field-Cured Specimens
405.7.2.1 Samples for strength tests of each class of concrete placed each day shall be taken not less than once a day ,or not less than once for each 120 m3 of concrete, or not less than once for each 500 m2 of surface area for slabs
405.7.4.1 If required by the engjneer~of~record, rcsults of strength tests of cylinders cured under field conditions shall be provided.
or walls.
405.7.4.2 Ficld .. curcd cylinders shall be cured under field conditions, in accordance with "Practice for Making and Curing Concrete Test ,)"'pecimens ill Ih(~ Fidd" (ASTM C 31M).
405.7.2.2 On a given project, if the total volume of concrete is such that the frequency of testing requireo. by Section 405.7.2.1 would provide less than five strength tests for a given class of concrete, tests shall be made from at least nvc randomly selected batches or from each batch if 'fewer than five batches are used. 405.7.2.3 When total quantity of a given class of concrete is less than 40 m3, strength tests arc not required when evidence of satisfactory strength is submitted to and approved by the engineer. 405.7.2.4 A strength test shall be the average of the strengths of two cylinders made from the same sample of concrete and tested at 28 days or at test age designated for determination offe. 405.7.3 Laboratory-Cured Specimens 405.7.3.1 Samples for strength tests shall be taken in accordance with "Method of Sampling Freshly Mixed Concrete" (ASTM C 172). 405.7.3.2 Cylinders for strength tests shall be molded and laboratory cured in accordance with "Practice for Making and Curing Concrete Test Specimens in the Field" (ASTM C 3 J M) and tested in accordance with "Test Method for Compressil'e Strength (~r Cylindrico! Concrete 5jJecimefls" (ASTM C 39M).
405.7.3.3 Strength level of an individual class of concrete shall be considered satisfactory if both the following requirements are met: I.
Every arithmetic average of any three consecutive strength tests (see Section 405.7.2.4) equals or exceeds
I,· . 2.
No individual strength test (average of two cylinders)
falls below.r· by more than 3.S MPa, when f'r is 35 MPa or less; or by Illore than 0.1 Of'e when Fe is more than 35 MPa. 405.7.3.4 If either or the requirements of Section 405.7.303 arc not mel, steps shall be taken to increase the average or subsequent strength test results. Requirements of Section 405 .7.5 shall be observed if the requirement of' Item 2 of Section 405.7.3.3 is nol mel.
405.7.4_3 Field-cured test cylinders shall be molded at the same timc and from the same samples as laboratory-cured test cylinders.
405.7.4.4 Procedures for protecting and curing concrete shall be improved when strength of field-cured cylinders at test age designated for determination of fe is less than 85 percent of that of companion laboratory-cured cylinders. The 85 percent limitation shall not apply if field-cured strength exceedsf,. by more than 3.5 MPa. 405.7.5 Investigation of
Low~Strength
Test Results
405.7.5.1 If any strength test (see Section 405.7-2.4) of laboratory-cured cylinders falls below specified values of Ie by more than 3_5 MPa (see Section 405.733. Item 2) or if tests of field-cured cylinders indicate deficiencies in protection and curing (see Section 405.7.4.4), steps shall be taken to ensure that !oad-carrying capacity of the structure is not jeopardized.
405.7.5.2 If the likelihood of low-strength concrete is confirmed and calculations indicate that load-carrying capacity is significantly reduced, tests of cores drilled from the area in question in accordance with "M(!(hod of Obtaining alld Testing Drilied Cores and Sawed Beams of Concrete" (ASTM C 42M) shall be permitled. In such cases, three cores shall be taken for each strength test more than 3.S MPa below specified value off,·. 405.7.5.3 If concrete in the structure will be dry under service conditions, cores shall be air dried (temperatures ISoC to 25°C, relative humidity less than 60 percent) for seven days before test and shall be tested dry. If concrete in the structure will be Illore than superficially wet under service conditions, cores sh;dl be immersed in water for al least 40 hours and be tested wet. 405.7.5.4 Concrete in an area represented by core tests shall be considered structurally adequate if the avcnlge of three. cores is equal to at !east 85 percent 01'/,. and if no single corc is Jess than 75 percent ofF.. Additional testing of coreS extracted from locations represented by erratic core strength results shall be permitted .
Association of Structural Enqll inors of tile PhdlPPIIWS
CHAPTER 4 . Concrete
405.7.5.5 If criteria of Section 405 .7.5 .4 arc not met, and if suuctural adequacy remains in doubt, the engineer of record shall be permilled to order a strength evaluation in accordance with Section 420 for the Cjllestionable portion of the structu re, or lake other app ropriate action. 405.7.6 Sleel Fiber-Reinforced Concrele
405.7.6.1 Acceptance of !'acei libcr-rcinforccd concrete used in beallls in accordance with 41l.6.6.1(6) shall be determined by testing in accordttnce with ASTM C J609. In addition, strength tes tin g shall be ill accordance wi th 405.7.1.
405.7.6.2 Steel tiber-reinforced concrete shall be co nsidered acceptable for shear resistance if co nditions ( I), (2), and (3) are satisfied: 1.
2.
3.
i
!i
The weight of deformed sleel fibers per cubic rneter of concrete is greater (han or equal to 60 kg. The residual strength obtained from Ocxural testing in accord;lI1ce with ASTM CI609 al
405.8 Preparation of Equipment and Place of J)eposit 405.8.1 Preparation before concrete pl
1.
All equipment for mi xing and transponing co ncrete shall be clea n;
2.
All debris shall bc rcmoved rro m Sp
3.
Forms shall be properl y coa ted;
4.
Masonry filler II nits th ill will be in cont3C1 wil h co ncrete shall be weI! drench ed;
5.
Reinforcement sha ll he thoroug hl y dean of dc le(Criotls coatings :
6.
Water shall be removed from place of deposit before co ncret e. is placed unless a trernie is (0 he used or unl ess ot herwise permitted by lhe engi neer:
7.
4-25
All iait
405.9 Mixing
405.9.1 All concrete shall be mi xed unt il there is a uniform distributi on of materials and shall be discharged completely before mi xer is recharged. 405.9.2 Read y-mi xed concrete shall be mixed and delivered in accordance with requirements of "Specifications for Ready· Mixed COllerete" (ASTM C 94M) or "Specifica tiolls Jor COII Cf'ere Made by Volumerric Batching and COlllinllolls Mixillg " (ASTM C 685M). 405.9.3 Job-mixed concre te shall be mixed in accordance wi th th e following: I.
Mixing shall be done in a batch mixer of an appro ved Iype;
2.
Mixer shall be rotated at a speed recommended by the lllanuf,lcturcr;
3.
Mixing sh all be continued for at least
4.
After all malerials are in lhe dru m, unless a shorter lime is shown to be satisfactory by the mi xing un iformit y tests of "Specifications for Ready-Mixed COflcre{(:"
1 ~ l/2
minutes
(ASTM C 94M) ;
5.
Materials handling, batching and mixing shall conform to applicable provisions of "Specifications f or ReadyMixed COllcrete" (ASTM C 94 M) ;
6.
A de wilcd record shall be kept to identi fy:
a.
Number of batr hes produced;
b.
Proporti ons of materials used;
c. d.
Approximatc structure;
location of final
deposi t in
Time and date of mixing and placing.
405.10 Conveying
405.10.1 Concrete shall be co nveyed from mix er to place of fi nal depo!\it by me thods th ilt wi ll preven t separation or loss of materi al",. 405.10.2 Conveyin g equipmen t shall be capable of provid ing a su ppl y of concrete at si te of place ment wi thout .separati on of ingredients and without interrupti ons sufficicnt to permit Joss or plas ti ci ty b ~lwcen successive increments.
111
N3 honl.~! S tructural Code or the Philippines 6 Edillon Volume 1
4-26
CHAPTER 4 - Concrete
405.11 Depositing 405. 11.1 Concrete shall be deposi ted as nearly .s practicable in its final position to avoid segregati o n due to
fe-hand li ng or Oowing. 405.11.2 Concreti ng shall be ea rned on at such a rat e th at
405.12.3.2 Accelerated curing s hal l provide a compressive s trength of concreLe at the load stage considered at least equal to required design strength at th ai load stage. 405.12.3.3 Curing process sholl he such as 10 produce concrete with a durabil ity at least eq~li va lent to the curing method of Sccti on 405 .12. 1 Or 405.12.2.
concrete is at all times plastic and fl ows readil y in to spaces between rcinforccnwn!.
.
405.11 .3 Concrele th.t has partially hardened or been con taminated by foreign materials shall not be deposi ted in the structul"C;.
405.12.4 When required by the engineer, suppl ementary strength tests in accordance with Secti on 405 .7.4 sh all be perfomled to assure Lhat curing is satisfactory. 405. 13 Hot Weather Requirem ents
405.11.4 Re-tcmpcred concrete or concrete that has been remixed after initial set shall.nol be used unless approved by
the engi neer:-of-record. 405.11.5 AfLer conc~eting is started. it shall be carded on as a continu ous operati on until pl.a cing of a panel or secti on, as defined by ils boundaries or prcdcrcnnjncd joints, is co mplet ed, except as permitted ' or prohi bi ted by Secti on 406.4.
During hot weather, proper attent ion sha ll be given to ingredients, production methods, handl in g, placi ng. protection and cu rin g [Q prevent excessive concrete temperamres or water evaporat ion th at may im pair required s tren,gllt or ser:'ic~abilit y of the member or s (ruclUrc.
. ,,"t; ~)i: '/
405.11.6 Top surfaces of veI1icall y fo rmed lifts shall be generall y leve l. 405.11.7 When const rucl ion joints are required. joints shall be made in accordance wit h Seclion 406.4, 405.11.8 All conCrele shall be thoroughly consolid.ted by su itable means during placement and shall be thoroughly worked around reinforcement and embedded fixtu res and into corne rs of forms . 405. 12 C u ring 405.12. 1 COllcre le (other tha n high -ea rly·stren gth) shall be mai ntained a'bove wOe and in a moi st condition for at Icast lhe fi rst sev~n days after placement, except when cu red in acco rd ance with Seclion 405.12,3. 405. 12.2 High-cnrly-s lrength concrele shall be ma intained above lOoe and in a moist condi ti o n for at least (he first three days, cxcc~t w hen cu red in accordance wilh Section 405. 12.3 . 405.12.3 Accelera ted C uring 405. 12.3.1 C uring by hig h-press ure stenll1, steam at atmospheri c pressure, heat and mo isture o r other accepted processes, Ill Hy be employed to accelerate strength g nin and redu ce time of cu ring,
Association of Stru ctu ra l Engineers of the Philippines
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,: ,~:l}.,~.<~ ~~
CHAPTER 4 . Concrele
I.
2.
4·27
The Slructural analysis and concrete strength data used in planning and implementing form removal and shoring shall be furnished by the co ntractor to tbe building official when so requested . No co nstru ction loads shall be supp0l1ed on, or any shoring removed from, any part of {he slmcturc under
constructioll exce pt when that pan ion of the structure in com bination wi th remaining forming and shoring sys tem has sufficient stre ngt h to ~ upport safely its weight and IOilds placed thereon.
406.1 Design of Formwork
406.1.1 Forms shall result in a final structure thaI conforms to shapes, lines and dimensions of the members as required by the design drawings and spccificmions.
I
406.1.2 Forms shall be substantial and sufficiently tight to prevent leakage of mortar.
I I
406.1.3 Fonns shall be properly braced or tied together to maintain posi lion and shape. 406.1.4 Forms and their supports shall be designed so as not 10 damage previously placed structure. 406.1.5 Design of fo nnwork shall include co nsideration o r the following factors:
1.
Rate and method of placing concrete;
2.
Construction loads, including verti cal, horizon tal and impact loads;
3.
Special form requi rements for constluction of shells. folded plates , do mes, architect ural concrete or similar types of elemen ts.
3.
Sufficient slIenglh shall be demonstrated by structura l anal ysis considering proposed loads, strength of forming and shoring system and concrete strength data. Concrete streng th data may be based on tests of fi eld· cured cylinde rs or, when approved by the en g ineer~o f· record, on ot her procedures to evaluate concrete slrength.
406.2.2.2 No construction loads exceeding the combination of superimposed dead load plus specified live load shall be supported on any unshorcd pOr1i on of the stmctu rc under constnlction, unless anal YS is indicates adequate strength to support such additional loads. 406.2.2.3 Form suppo rts for prestressed concrete members shall not be removed uillil suffi cient prestressing has been app lied 10 enable pre.o:;tresscd members to carry their dead load and an ticipated construction loads. 406.3 Conduits and Pipes Embedded in Concrete
406.1.6 Forms for prestressed conc rete members shall be designed alld constnlctcd to permi t 1ll0VC IllCIlI of Ihe member wi lhollt damage duri ng application of prestressin g force.
406.3.1 Conduits. pipes an d sleeves of any material not h,mnful 10 concrele and within limi tations of Ihis subsection Illay be embedded in eOllcretc with approval of the engineer. provided they arc /lot considered 10 rcpl ace struclUratty the disp laced concrete.
406.2 R emoval of Forms, Shores a nd Reshorin g
406.3.2 Conduits and pipes of alumin um shall not be embedded in siructura l co ncrete unless effectively coared or covered to prevent alu min uffificoncrete reaction or electrol yt ic action bet ween aluminum and steel.
406.2.1 Removal of Forms
Forms shall be rem oved in such a manner as nol to impair safety and servicc(lbility of the stm cture. Concrete to be exposed by form re mova l shalt ha ve suffi cient st rength not to be damaged by removal opcnl tioll. 406.2.2 Rcmov:;1 of Shores and n cshol'ing The pro visio ns of Secti on 406.2.2.1 through 406. 2.2.1 shall apply to slabs and heams except whe re cast Oil the grou nd.
406.2.2.1 I3efore starting cons tru clioll , th e co ntra<.:tor shal] develop a proced ure and schedu le for removal of shores and imaallatioll of reshorcs nnd for calculating Ihe IOilds trans ferred to the sll1lcturc during the process.
4Q6.3.3 Conduits, pipcs and sleeves passing through a slab. wall or beam shall not impair significantly the strength of the cons tnJ crioll . 406.3.4 Co nduit s within a co lumn th e area of <.:fOSS whi ch is required
and pipes, with their fittings, embedded sha ll not displace more than 4 pcrcclH of sectio n on wh ich stren gth is calcu lated or fo r lire protection.
406.3.5 Except when plans for conduits and pipes arc approved by th e structural enginee r, co ndu its nnd pipes embedded within a slab. wall or beam (ot her than those merely pass ing through) shall satisfy the following: 111
National Structural Code of the Philippin es 6 Edition Vo lume 1
i
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CHAPTER 4 - Concrete
406.3.5.1 TI,ey shall not be larger ill outside dimension than one third the overall thickness of slab, wall or beam in which they are embedded.
406.3.5.2 They shall be spaced not closer than t hrcc diameters or widths 011 cenler. 406.3.5.3 They shall not imp
406.4.2 fmmediately before new concrete is placed, all construction joints shall be wetted and standing water removed. 406.4.3 Construction joints shall be so made and located so as not to impair thc strength of the. structurc. Provision shall be made for transfer shear and oth er forces through cOJlstruction joints. Sec Sect ioJl 411.8.9.
or
406.4.4 Construction joints in floors shall be located within the middle third of spans of slabs, beams and girders. 406.4.5 Joints in girders shall be offset a minimum distance of two times the width of intersecting beams.
provided:
406.3.6.1 They arc not exposed to IlJst ing or other deterioration. 406.3.6.2 They
406.4.6 Bcams, girders or slabs supported by columns Or wHlls shall not be cast or erected until concrete in lhe vert ical SUppOl1 mcmbers is no longer plastiC.
not thinner than standard Schedule 40 sleel pipe. 406.3.6.3 They hnve a nominal inside diameter nO{ over 50
mm and arc spaced
nol
less than three diameters 011 centers.
406.4.7 Bcams, girders, haunches, drop panels and capitals shall be placed monolithically as part of a slab systcm , unless otherwise shown in design draw ings or specifications.
406.3.7 Pipes and fi ttings shall be designed !O resist effects of the material, press ure and temperature to which they will be subjected . 406.3.8 No liquid, gas or vapor. except water not exceeding 30:C or 0.35 MPa pressure, shall be placed in (he pipes umillhe concre te has mlained its design strength . 406.3.9 In solid slabs. piping. unless it is used for radiant healing or snow melting. shall be placed between lOp and bOltom reinforCCIllI!I)( . 406.3.10 Conc rete cove r for pipes. condu it and linings shall not be less than 40 mill for concrete exposed to earlh Of wc,lthc r, or less Ihan 20 mm for concrete not exposed 10 weather or in con tact with ground. 406.3.11 Reinforcement wilh an arca not less [han 0.002 times the area of co ncrcte section shall be provided normal to the piping.
406.3.12 Piping and «mouit slwW be so fabricated and insta lled thai cutt ing. bendin g or displacement of rei nforccment from its proper lociHion willnOl he requiretl . 406.4 Construction Joints 406.4.1 Surface of concrele constructiun joints shall be cleaned and laitancc rcmoved.
Association of Structural Engineers of the Philippines
CHAPTER 4 - Concrete
4-29
Table 407-1 - Minimum Diamelers or Bend Bar Size ~IO mm Ihrough <1>25 mOl q,28 mm , ~32 mm and
407.1 Notalions
d
db
::::: distance from extreme compression fiber to cen troid of tension reinforcement, mm ;: nominaJ diameter of bar. wire or prestrcs~ing s lrand,
mm
~36 nun
q,42 mm and
~58
mm
Minimulll Diameter
6d,
3d, 10d,
407.4 Bending of Reinforcement
lei = comprcssve
h
strength of concrete at li me of initia l preSlress. MP. = specified yield strenglh or non prestressed
407.4.1 All reinrorcemenl shall be ben I co ld, unless otherwi se pemlillcd by the engineer-oF-record.
rej nforcemen t, MPa
Ld :; developmeru length,
mOl. See Section 4 12.
407.2 Standard Hooks
"Standard hook " as used in this code is one of the following: 407.2.1 180-degree bend plus 4d" eXlension, bUI nOI less than 60 111m at free end of bar. 407.2.2 90-degree bend plus 12d" extension al rree end or bar. 407.2.3 For stirrup and tie hooks:
I.
q,16 mm bar and smaller, 90-degree bend plus 6(1" extension at free end of bHr; or
2.
q,20 mm and q,25 mm bar. 90-degree bend , plus 12(/" extension al frec end of bar; or
3.
$25
nUll
bar and smaller, 135-degrce bend plus 6(h
extension at free end of bar.
407.4.2 Reinforcement panially embedded in concrete shaH not be field bent , except as shown on the design drawings or permitted by the engineer-or-record. 407.5 Surface Conditions of Reinfol'eement 407.5.1 At the time concrete is placed, reinforccment shall be free from mud, oil or other nonmctallic coatings that decrease bond. Epoxy coatings of steel reinforcement in accordance with Sections 403.6.3.8 and 403.6.3.9 shall be
pennitted. 407.5.2 Reinforcement, except prestressing tendons. with ru st, mill scale or a combination of both, shall be considered satisfactory, provided the minimum dimensions (including height of defonnations) and weight of a hand -wire-brushed tcst specimen comply with applicable ASTM specifications re ferenced in Section 403.6. 407.5.3 Prestressing tendons shall be clean and free of oi!, dirt. scale, pitting and excessivc lU St. A light coating of rust shall be permiltcd.
407.2.4 Seismic hooks as defined in Section 402. 407.6 Placing Reinforcement 407.3 Minimum Bend Diameters 407.3.1 Diameter of bend measured on the inside or the bar. other Ihan ror stirrups and lies in sizes q,1 0 mm Ihro ugh ~ 16 mm, shallnol be less Ihan Ihe values in Table 407- \. 407.3.2 Inside diameter of bends for sti rrups and tics .shall not be less than 4db for ~16 mm bar and smaller. For bars larger (han 4>16 mm, diameter of bend shall be in accordance wilh Table 407-1.
407.6.1 Reinforcement. prestressing tend ons and ducts shall be accurately placed and adequately slipponcd before concrete is placed. and shall be secured against displacement wilhin to lerances of lhis section. 407.6.2 Un less OIherwise specified hy the engineer-of\!cord , reinrorcemenL , prestressing lendons and preslressing
ducts shall be placed wilhin Ihe followin g tolerances:
407.3.3 Inside diameter of bends in welded wire fabric
(plain or deformed) for stirrups and lies shall not be less than 4(h for deformed wire larger thall MD40 and 2lh for all oth er wires. Bends with inside diameter of less than '8d" shall not be less than 4(", from nearest welded intersection. National Structural Code of th e Philippines 6
111
Edition Volume 1
~·30
CHAI'TER 4 . Concrete
407.6.2.1 Tolerance for depth d, and Ilummum concrete cover in flexural members, walls and compression members s hall be as follows: r-· Tolerance on Effective Dcplh. Tolerance on d Minimum Concrete
d
d ,; 200
_.
Co'vcr I11Ill
2UO /TIm
± lOmm
·10
± 12mm
- 12 ,nUll
mOl
except that to lerance for the clear distance (0 fonned soffi ts s hall be minus 6 mill and lOlerance for cover shall not exceed minus one-third the minimum concrete cover required by the approved plans or specifications. 407.6.2.2 Tolerance for longitudinal localion of bends and
ends of reinforcement shall be ±50 mm except at discontinuous ends of members where tolerance shall be
407.7.3 In spirally reinforced or lied reinforced compression members, clear distance between longitudin al bars shall not be less than LSd. or less than 40 mm. See also Section 403.4.2. 407.7.4 Clear distance limitation between bars shall apply also to the clear distance between a contact lap sp lice and adjacent splices or bars .. 407.7.5 In walls and slabs olher than concrete jOiSl construction, primary Oexural reinforcement shall not be spaced farther apan than three times the wall or slab thickness, nor farther than 450 111m . 407.7.6 Dundled Dars 407.7.6.1 Groups of parallel rein forcing bars bundled in contact to ac~ as a unit shall be limited to four bars in One bundle.
±12 mill at the discontinuous ends of brackets and corbe ls.
and ±25 mm at the discontinuous ends of other members. The tolerance for concrete cover of Section 407.6 . 2. 1 shall also app ly at the discontinuous ends of members. 407.6.3 Welded wire fabric (with wire size not greater than MW30 or M030) used in slabs not exceeding 3 III in span shall be permitted to be curved from a point near th e top of s lab over the support to a point near the bottom of slab at midspan, provided such reinforcement is either continuous ove r, or securely anchored al, support. 407.6.4 Welding of crossing bars shall not be permitted for asse mbly of reinforcement.
Exceptions: 1.
Rein/arcing steel bars are not required by design.
2.
When specifically approved by the engineer4o,f.record, welding of crossing bars for assembly purposes ill Seismic Zone 2 may be permit/ed, provided that data are submitted to the engineer to show that rht?Te is 110 detrimental effect on the actioTl of the structural member as a result afwelding of the crossing b.ars.
407.7 Spacing Limits for Reinforcement 407.7.1 The mini mulll clear spacing between parallc:J bars in a layer sha ll he (It. but not less than 25 1l1111 . See also Section
40lA.2. 407.7.2 Where paralic! reinforcement is placed in two or morc layers, bars in thc upper layers Sh'lll be placed directly ahove bars in the bottom layer with clear distance between la yers not less than 25 mm.
407.7.6.2 Bundled bars shall be enclosed within stilTUPS or ties. 407.7.6.3 Bars larger Ihan ~36 mm shall not be bundled in beams. 407.7.6.4 Individual bars within a bundle terminated within the span of flexural members shall term inale at different points with at least 40db stagger. 407.7.6.5 Where spac ing limitations and minimum concrete cover are based on bar diameter (//>, a unit of bundled bars shall be trealed as a single bar of a diameter del;ved from the equivalent total area. 407.7.7 Prestressing Te ndons and Ducts 407.7.7. 1 Center !0-center spacing of pre-tensioning tendons at each end of a member shall not be less than 5db for wire. nor 4db for strands. except that if concrete strength at transfer of prestress. c; is 28 MPa or more, min imum center to center spacing of strands shall be 45 mm for strands of 12 mm norrtinal diameter or smaller and 50 mm for strnnds of 16 mm nominal diameter. See also Section 403.4.2. Closer vertical spacing .tnd bundling of tendon s sha ll be permiHcd in the middle portion of a span. 4
r
407.7.7 .2 Bundling of post-lensioning duels shall be permitted if it is shown that concrete can be sati sfactorily placed and if provision is made to prevent the tendons , wlF ~!! tensioned, from breaking through (he duct.
Association of Structuf(ll Engineers of the Philippine s
CHAPTER 4 . Concrete
4-31
407.8 Concrete Protection for Reinforcement 407.8.1 Cast-in-Place Concrete (Nonprestressed) Unl ess a greater cover is required by Section 407.8.6 or 407.8.8, speci fied cover for reinforcement shaJ] nOlless than Ihe following:
,.
407.8.2 Precast Concrete (Manufactured Under Plant Control Conditions) Unless a greater cover is required by Section 407.8.6 or 407.8.8, specifi ed cover for prestressed and nonpres lrcssed
reinforcement , dUCIS. and end fittings shall following:
CQllcrelc cast against and pcnnancnli y
I.
exposed to earth ........................ ................. 75 mm 2.
mm bar through ~36 nun bar .... . ~I 6 mm bar, MW200 or MD200 wire, and sJllaller ....................................... . 3.
Concrete exposed to earth or weather: a. Wall panels:
Concrete exposed to earth or weather: ~20
40mm ~42 mm and ~58 mm bars 4>36 bar and smaller, prestressing tendons larger than 40 mm and smaller, MW200 or MD200 wire and smaller. __ ... 20 mm
SO mm
40ml11
b. Olher members:
Concrete not exposed to weather or in
contact with ground: a.
b.
c.
~42 and .p58 bars, prestressing lendons larger than 40 mm ................. ,.".. .. .... ...... <1>20 through <1>36 bars, prestressing
Slabs, walls, joists:
.p42 mm and .p58 nUll bars
40mm
~36
20 nun
mm b,lfS and smaller
less than the
Minimum Cover
Minimum Cover I.
110t
tendons larger than 16 mill through 40mm ...... ......... ........ ..............
Beams, columlls:
PrimalY reinforcement, tics, stirrups, spirals .............................. _.... 40 mm
tendons 16 mm diameter and smaller, MW200 or MD200 wire, and smaller.....
Shells, folded plale members: .p20 mm bar and larger 20 mm q,16 mm bar, MW200 or MD200 wire, and smaller ._...................... ......... 12 mill
2.
50 111m
40 mill
30
nll11
Concrete not exposed to weather or in contact with ground :
a. Slabs, walls, joists:
<1>42 mm and 4>58 mm bars, prestressing tendons larger than 40 mm ................
30 mm
Prestressing tendons 40 fnm .... 20 111m and smaller ... 4>36 mrn bar and smaller, MW200 or 15 mm MD200 wire and smaller. b. Beams, columns: Primary reinforcement db but flol less than 4J 15 mm and need not exceed ........ 40 mm Ties, slirrups, spirals ........... ............... 10 mill
c.
Shells, folded plate members: Prestressing tendons. mm bur and larger 16nll11 bar, MW2000r MD200 wire, and smaller .... ..... . ~20
Nationa l Structural Code of the Pllllippines 6
111
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20 nun J5mlll IOmm
4-32
CHAPTER 4 - Concre le
407.8.6 Corrosive Environmcnts
407.8.3 Cas t·ln· Place Concrete (Prestressed) 407.8.3.1 Un less a greater cover is required by Sections 407 _8_6 and 407.8_8, specified cover for prestressed and
nOllprcstrcssed reinforcement, duc ls and end filtings, shall not less Ih(lll the following: Minimum Cover
1. 2.
3.
Concrete cast against and permanently exposed 10 earth Concrete exposed
LO Cll11h
.. .
75
lii;ll
or weather:
Wall panels. slabs, joislS
2S mm
Other members ........... .... .
40mm
Concrete not exposed to weather or in
co ntact with ground: a.
Slabs, walls, joists
b.
Bc:uns. columns:
c.
In corrosive envi ronments or other severe ex pOsure conditi ons, amount of concrete protection shall be. s:!iWhly increased, and the pel1inent requirements for concrete bas.cd o n applicable exposure categories in Section 40't shall be met, denseness and nonporosity of protecting concrcle shall 'be considered, or other protection shall be provided. 407.8.6.1 For prestressed concrete members exposed to corrosive environments or other severe exposure rilleg!"·' · such as Ihose defined in Section 404, and whid; .lfC classi fied as Class T or C in Section 418.4.3. spc:cdl e rl concrete cover shall not be less (han 1.5 limes tlH: !.', ··.· C t·or prestressed reinforcement required by Sections filJi X.i. <. Iid 407.8.3. This requirement shall be permitted to be \Vaiv~d if the precompressed tensile zone is not in tensi on under sus tained loads.
20 mm
Plimary reinforcement
40111111
Tics, stirrups. spirals
25 mm
407.8.7 Future Extensions Exposed reinforcement, insens and plates inlcndcd for bonding with future extcnsions shall be prot<~ {;l(;d from
corTOsioll.
Shell s, folded plate members: 16mm bars, MW200 or MD200 wire,
and smaller ......... ". ... ... .. ........ ...... 10 nun Olher reinforcement ............ lit. > 20 ml11 407.8.3.2 For pres tressed concrete members exposed to earth , weather o r corrosive environmcnl s. and in which permissible ten sile s tress of Sec ti on 41 8.5. 1. Item 3. is exceeded. minimum cove r shall be increased 50 percent. 407.8.3,3 For pres tressed concrcte members manufacturcd under plant comrol con ditions, min imum concrete cover for nonpreslressed reinforcement shall be as required in Section 407.8_2.
407.8.8 Fire Proteclion
If the National Building Code, of which the N;Jli () nal Structural Code of the Philippines (onns a p:lri, j·l:qi1frt :: a thickness of cover for fire protection greater than (he minimum concrete cover specified in Seciion:. tl( ri .,; . 1 through 407.8.7, such greater thickness shall he ~ p(;(; iI H .. j , 407.9 Special Reinforcement Details for Columns 407.9.1 Offset B:trs Offset bent longitudinal bars shall confoml to (he followir'f::
407.9.1.1 Slope of inclined portion of an offset bar with (lxis
of co lumn shall not exceed I in 6.
407,8.4 Bundled Bars
For bundled bars, minimum concrete cover shall not be less than the equivalent diameter of the bundle, but need not be greater than 50 mill; except for concrete cast against and permanently exposed to earth, minimum cover shall not be less than 75 mill. 407.8.5 HC:ld ed Shear Stud J{cinfor(.'clI1cnt
For headed shear stud reinforcement, speci fied co ncrete cover for the heads or base raits shall not be Ic..o;s than thill requi red for the re inforcement in the type of member in which th e headed shear stud reinforcement is pl'lced.
407.9.1.2 Portions of bar above and below all
off~;c(
shall be
parallel to axis of column. 407.9.1.3 Horizontal support at offset bl'n ds ~ ! d1 ; ll~ prov ided by lateral li es, spirals or purts of {Ii;: fL·,,!· constru ctio n. Hori zontal suppo rt pro vided shaH lie t1. ;.i;·, -J to res ist o lle and one·half limes the horizontal ,~}jllp: l(le I H .;f th e computed force in the inclined portion or :w urr·,:'1 11. '. Late ral lies or spirals. if used, shall be placed /lO! m Oil: rb,q) 150 mOl from po ints o f bend. 407.9.1.4 Offset bars shall be belli before ,,1,''C'nc'" i"
forms. See Section 407.4.
Association of Structural Engineers of the Philippines
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CHAPTER 4 - Concrete
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407.9.1.5 Where a column face is offset 75 mm or greater. longitudinal bars shall not be offset bent. Separate dowels, lap spliced with the longitudinal bars adjacent to the offset column faces, shall be provided. Lap splices shall conform to Section 412.18.
407.11.3 It shall be permitted to waive the lateral reinforcement requirements of Sections 407.11, 410.17 and 418.12 where tests and structural analyses show adequate strength and feasibility of construction.
407.9.2 Steel Cores
Spiral reinforcement for compression members conform to Section 410.10.3 and to the following:
407.11.4 Spirals Load transfer in structural steel cores of composite compression members shall be provided by the following: 407.9.2.1 Ends of structural steel cores shall be accurately finished to bear at end-bearing splices, with positive provision for alignment of one core above the other in concentric contact. 407.9.2.2 At end-bearing splices, bearing shall be considered effective to transfer not more than 50 percent of the total compressi ve stress in the steel core. 407.9.2.3 Transfer of stress between column base and footing shall be designed in accordance with Section 415.9. 407.9.2.4 Base of structural steel section shall be designed to transfer the total load from the entire composite member to the footing; or, the base may be designed to transfer the load from the steel core only, provided ample concrete section is available for transfer of the portion of the total load carried by the reinforced concrete section to the footing by compression in the concrete and by reinforcement.
407.11.4.1 Spirals shall consist of evenly spaced continuous bar or wire of such size and so assembled as to permit handling and placing without distortion from designed dimensions. 407.11.4.2 For cast-in-place construction, size of spirals shall not be less 10 mm diameter. 407.11.4.3 Clear spacing between spirals shall not exceed 75 mOl or be less than 25 mm. See also Section 403.4.2. 407.11.4.4 Anchorage of spiral reinforcement shall be provided by one and one-half extra turns of spiral bar or wire at each end of a spiral unit. 407.11.4.5 Spiral reinforcement shall be spliced. if needed. by anyone of the following methods: I.
407.10 Connections 407.10.1 At connections of principal framing elements (such as beams and columns), enclosure shall be provided for splices of continuing reinforcement and for anchorage of reinforcement terminating in such connections.
Lap splices not less than the larger of 300 mm and the length indicated in one of (a) through (e) below: a.
deformed uncoated bar or wire
48 db
b.
plain uncoated bar or wire
72 db
c.
epoxy-coated deformed bar or wire.
72 db
d.
plain uncoated bar or wire with a standard stirrup or tic hook in accordance with Section 407.2.3 at ends of lapped spiral reinforcement. The hooks shall be embedded within the core confined by the spiral reinforcement .................................... ........ 48
407.10.2 Enclosure at connections may consist of external concrete or internal closed ties, spirals or stirrups. e.
407.11 Lateral Reinforcement for Compression
Members 407.11.1 Lateral reinforcement for compression members shall conform to the provisions of Sections 407.11.4 and 407.11.5 and, where shear or torsion reinforcement IS required, shall also conform to provisions of Section 411. 407.11.2 Lateral reinforcement requirements for composite compression members shall conform (0 Section 410.17. Lateral reinforcement requirements for prestressing tendons shall conform to Section 418.12.
shall
2.
(h
epoxy-coated defonned bar or wire with a standard stirmp or tie hook in accordance with Section 407.2.3 at ends of lapped spiral reinforcement. The hooks shall be embedded within the core confined by the spiral ..... 48 db reinforcement
Full mechanical or welded splices in accordance with Section 412.15.3.
407.11.4.6 Spirals shall extend from top of footing or slab in any story to level of lowest horizontal reinforcement in members supported above.
National Structural Code of the Philippines
ell Edition Volume 1
4·34
CHAPTEH 4 · Concrete
407.11.4.7 Where beams or brackets do not frame into all sides of a column, lics shall extend above tcnninmion of s piral to uonom of slab, drop panel, or shea r cap.
407. 11.4.8 III columns with capitals, spirals shall extend to level fit which the diameter or width of capital is twO times
il
Ihm of th e co lumn .
407.11.4.9 Spirals shall be held firmly in place and tru c to line. 407. 11 .5 Tic reinforcement for compression member!) shall conform to the following:
407.11.5.1 All non prestressed bars shall be enclosed by latcral (ies. a( least mID mOl in size for longitudinal bars U!32 111m or smalier. and at least rnl2 mm in ~ize for liI36 mm, rn42 mm. 1.!J58 111m bars. and bundled longitudinal bars. Deformed wire or we lded wire fabric of equivalent area s hall be permilled. 407.11.5.2 Vel1ical spac in g of lies shall not exceed 16 longitudinal bar tlinmetcrs , 48 ti e bar or wire diarneters, or leas t dimensioJl of the compression mem ber. 407.11.5.3 Ti cs sha ll be arranged slich tl1m every corner and alternate longitudinal bar shall have lateral SUppOI1 provided by the corne r of 11 tic with an included angie of not more than 135 degrees and a bar shall be nOt fanher than 150 mill clea r all each side along the lic from such a laterally supported bar. Where longi tudinal bars arc IOC.HCd around the perimcte r of a c ircle, a complete circuhu· lie shall be pcnnincd. 4 07. 11.5.4 Tics shill! be locateo vertically not more than on e half a tic spncing above the lOp of footing or s lab in an y slOry and shall be spaced as provided herein to nol more than o ne half a tic spacing below the lowest horizontal reinforcemellt in slab, drop panel, or shear CHP above. 407.11.5.5 Whe re beams or brackets frallle from fOll r d irec ti ons into
407.12 La teral Reinforcement for Flexural Members 407.12.1 Compress io n reinforcemen t in beams shall be enclosed by lies or stirrups satisfying the size ami spacing limitations in Section 407 .11.5 or by weld ed wire fabric of cq uiva icill area. Suc h tics or stirrups shall be provided throughout the di stan ce where compression re inforcement is req uired. 407.12.2 Lateral rei nfo rcemcnt fG!· nexural framing members subject to stress reversal s or to to rsion at slIppons shall consist of closed tics, closed stirrups, or spirals ex tending around Ihe flexural reinforcement. 407.12.3 Cl osed lies or Slil11Jps may be formed in one picce by overlapping standard stil11Jp or tie end hooks around a longi tudinal bar, or formed in one or two pieces lap spliced with a Class B splice (lap of 1.3Id ), or anchored ill accordance wi lh Section 4 12. 14 . 407. 13 Shrinkage a nd Te mpera ture Reinforcement 407.13.1 Reinforcement for sh rinka ge and tc mperalllre st resses normal to fl ex tlrnJ re inforccl'l1ent shal l be provided in structural slabs whe re the flexural rei nforceme nt extends in one direction o nl y. 407. 13.1.1 Shrinkage and temperature reinforcement shall be provided in accordance with ei the r Section 407.J3.2 or 407.13.3. 407.13.1.2 Where shrinkage and tempcrature movements arc significamiy restrained. the requirement s of Sections 408.3 .4 and 4093.3 sha ll be considered . 407.13.2 Deformed reinforcemcnt co nformin g 10 Sect ion 403 .6 .3 lIsed for shrinkage and temperature reinforcemcnt shall be provided in accordance with the following: 407.13.2.1 Area of shrinkage and te mp erature reinforcement
shall provide at leflst the fo ll ow ing ra tios of re inforcement area to gross con crete area, but not less than 0.00 14:
I.
Slabs where Grode 280 and Grade 530 deformed bars arc used ....... ... .. ......... .......... 0 .0020
2.
Slabs where Grade 4 15 deformed bars or welded wi re fabric (smooth or deformed) "re used .............................. ...... 0.0018
3.
Slabs where rei nforcement with yield . stress exceeding 415 MPa measured at 0.00 18 x415 a yield strain of 0 .35 percent is used
or
407.11.5.6 Where ,Hlehor bolls are pklccd in (he top columns or pe destal s , the bolls shall be enclosed by lateral reinforcement 111
J,
Association of StrtJ clural Englllcers of tile Phil ippines
CHAPTER 4 . COllcrele
4··35
407.13.2.2 Shri l1kage and tClllpcralu r~ rein forccmcllI shall be spaced nol f.wher ap,IJ1 than ri vc timcs the sla b lhickness or 450 mm.
2.
407.13.2.3 AI
A l non-con tin uous suppOl1S, the reinforce ment shall be anc hored to develop 1,. at the face of the support lIs in g II standard hook satisfying Sec ti on 41 2.6 or headed defonncd bar sa ti sfying Section 412 .7.
407.13.3 Prestressin g Icndons conforming to Scct ion 403.6.6 used for shrinkage ,lIld temperature reinforcement shall be provided ill accorda nce wilh the followi ng:
407.14.2.3 The co ntinuous moment reinforcement required ill Section 407. 14.2.2 shall bc enclosed by transverxe reinforcement or the Lype specified in Section 4 11.7.4.1. The transve rse rcinforcemenl Shilll be an chored as specified ill Section 4 11.7.4.2. The transverse rein forcement need not be extended thro ugh the coluilln .
407.13.3.1 Tendons shall be proportioned to provide a mini mu lll average co mpressive Sl rC!\s of 0.70 MPa on gross COll cretc area using effecti ve prestress, after losses, in accordance wi th Sccti on 418.7. 407.13.3,2 Spacing of prl.!s lrcssed te ndons shall not exceed i .8 meter.....
407.13.3.3 WIlen the spacing of pres tressed tcndOlls exceeds 1.4 Ill, ns at slab ed ges extending from the Slil b edge for a distance equal 10 the tendon spacing,
407.14 UCCJuircmcnts fo r Stru ctll ra lln tcgrity 407.14,1 III the dc/ailing of re info rce ment and connec ti ons. members of' . 1 structure shall be effectivel y tied toge ther (0 impro ve illlcgri ty of the ove ral l struc ture. 407.J4.2 For cast-I n-plan.' olllslnl<.'tion. llIinilllUlll r e quil'l~ lIlcnls :
I h~'
following sh;1I 1
c() ll s tillftl~
407,14.2. 1 In joist conslnll' ti oll. its delincd in Sections 408.14.1 through 01 08. 14.3. at lea~1 nile hO(t Olll har shall he continuous or shal l he spliced over the support wi th a Class B tens ion spl icc 0 ]' a Illct' h;m ic al ~)I' welded s plice satisfy ing Section 412. 1S .]
al tl w pcrilllt'!l:r of Ih e St I1l C!\lI\' sh,dl I'ci nrmccillcill O\:l! Ihe :-.pan kll gth p assin g region bounded hy l ile longitudilla l
I k:1Il1S
11 ;1\·\ , ~: ()llt i l1\1\1\1s
throu gh tht: rcinfnrcl'Illl'1lI o r I Ill! L"lliu llIl1 l'oll si:-tlllg I.
til'
( I ) and (2):
It'a.\( (llll' -s ixth nf the tens ion rc ill i'orn'm t'1I1 I'l'q uil'l'd for ll ~ga ti\'l: 11101111..'1\1 al the :-. uppOl'1. hU I no t k::-.s 111:111 t\V() 1);lrs:
1\1
At Icast onc-qual1cr reinforccment requi red two bars.
of thc posit ivc momcnt midspa n, bUI not less Ih'lll
aI
407.14.2.4 Where splices are required to salisfy Section 407, 14.2.2, (he lOp reinforcement shall be spliccd at or near midspan and boltom reinforcement shall be spliced near the support . Splices shall be Class B tension splices, or mechanical or welded splices satisfyi ng Section 4 12. i 5.3 . 407.14,2.5 In other than perimeter beams . where transverse reinforce ment as dcfined in Secti on 407 .14.2.3 is provided, there arc 110 addi tion al requirements for longitudinal reinforcement . Wh ere such transverse integrity reinforcc melll is nOt provided, nt least one-qual1cr of the positive 1l10lnCllI rein forcement at midspan, but not less than I WO ba rs, shall pnss through the regi on bounded by the longiludinal reinforccll1clHof thc COI Ulllll :lIld shall be co ntinuou s or shall be spliced over OJ' ncar the support wilh a Class B tens ion spli ce, or mec hanical or weld ed split:cs sa ti sf yi ng Section 412. 15.3. A I 11011 co ntinuous suppOI1S, the reinforccment sl1:111 he 'lIlchored 10 (ievel opJ~ at the face ()f Ihe SUPP()f1 using a standard hook sali s fying Section 4 12.6 or headed de forilled bar sa tisfying Sct: ti o ll 4! 1 .7. 407 ,14.2,(' For IlOll presLresscd two-way sl" b COllst rllCli ()]). set: Sel' tion 41 J .4.R.5. 407. 14.2.7 For prt:stressed two-way slab cOllslnlcli on. see Secti on 4 18. 13 .6 and 41 8 13.7 407. 14 ,) For precast concrc te
CO]l Slrut'l io n .
tcnsio]) lies
shall be provided in the transverse. longitudinal. and vcrtit'al dircction s and arou nd t h ~' perimcter o f the slrllc tll rc In ~rrl~\,:tivdy til' ek lll c lJt s toget her. The provisions of Sec ti on 4 I (,.!, shall "ppl)' .
.:107. 14.4 For lif, ·"I,,11 and ..t 18 . 1:IX
l'oll~trlll'tioll, St'C. St:t't ioIlS .~
1l.·tX 6
4·36
CHAPTEI, 4 . Concrete
Table 407-2 Steel Reinforcement Information Information on Sizes, Areas and Weights of Various Steel Reinforcements .• . .•.... .. _ . _ - - - - - _..•
.
- - - - - - . - _.
ASTM STANDARD
PHILIPPINE STANDARD (SI) ..
Nominal Diameter, mm 9.5 ..
12.7
Nominal Area, mm 2
71 _- _._-_
Nominal mass, kg/m
-----
'"
199
0.560 -------.- .--.. 0.994
_._.•.
10 -- ~-
. - 1-.
0.618 --~---
...
-,.-~---
12
113
0.890
16
201
1.580
20
314
2.465
n.a
n.a
19.1
284
2.235
22.2
387
3.042
n.a
3.973
25
510
79
--_..
1.552
• ..
25.4
Nominal mass, kg/m
•....
129
15.9
Nominal Area, mm 2
Bar Size Designation
.• ..._._- - - _.
491
..
~
i
3.851 ..
28.7
645
32.3 35.8
5.060
28
616
4.831
819
6.404
32
804
6.310
1006
7.907
36
1019
7.986
43.0
1452
11.380
42
1385
10.870
57.3
2581
20.240
58
2642
20.729
._... _•.•..... _.
. . .
--~
.."" •... _ . _ - - - - ' - . _ - - -
/\SSOC i8t ioil of Siructur81 Enqineers of tile Pll i lipPllll~' ;
i
~
CHAPTER 4 . Concrole
Table 407 -3 WRI Standard Wire Rein force men t AREA, mm' I m OF WIDTH FOR VARIOUS SPACINGS CENTER-TO-CENTER SPAC ING,nun
MW and MD SIZE -
PLAIN
DEFORMED
- - --_..
,
Nominal
Nominal
Diameter,
mass,
mm
kg/Ill
50
75
100
150
200
250
300
MW 290
MD290
1922
2.270
5800
3900
2900
1900
1450
1160
970
MW200
MD200 '.
15.95
1.570
4000
2700
2000
1300
1000
800
670
MW130
MD130
12.90
1.020
2600
1700
1300
870
650
520
430
MWI 20
MD I20
12.40
'0.942
2400
1600
1200
800
600
480
400
MWI OO
MDI OO
11 .30
0.785
2000
1300
1000
670
500
400
330
MW90
MD90
10.70
0.706
1800
1200
900
600
450
360
300
MW80
MD80
10. 10
0.628
1600
1100
800
530
400
320
270
MW70
MD70
9.40
0.549
1400
930
700
470
350
280
230
MW65
MD65
9. 10
0.510
1300
870
650
430
325
260
220
MW60
MD60
8.70
0.471
1200
800
600
400
300
240
200
MW55
MD55
0.432
1100
730
550
370
275
220
180
MW50
MD50
8.44 8.00
0.393
1000
670
500
330
250
200
170
MW45
MD45
7.60
0.353
900
600
450
300
225
180
150
MW40
MD40
7.10
0.314
800
530
400
270
200
160
130
MW35
MD35
6.70
0.275
700
470
350
230
175
140
120
MD 30
6.20
0.236
600
400
300
200
150
120
100
MD 25
5.60
0.196
500
330
250
170
125
100
83
5.00
0.157
400
270
200
130
100
80
67
MWIS
4.40
0.118
300
200
150
100
75
60
50
MWIO
3.60
0.079
200
130
100
70
50
40
33
2.50
0.039
100
67
50
33
25
20
17
MW30 1----MW 25 MW20
MW5
-
--- - ----
--
..
_-_.
~ -37
4-38
CHAPTEfl4 - Concrete
408.3 Loading
SECTJQN 408 ANALYSIS AND DESIGN :'
408.3. 1 Des ign prov isions of thi s code nrc based on the ass umption that 51 ructurcs sha ll be designcd to resist all applicable loads.
GENERAL CONSIDERATIONS 408.1 Notations
A. ;;: area o fnonprcstrc.o;:scd tension rci n(ol'CCI1lCnL I11m ~ A '. ;;: area of compression rei nforce ment, 1111112 b ;;: width of compression face of member, mm d ::: di stance from extreme compressi oll fiher 10 ce nt roi d of (ension rcinforccmcllI. 111m E, E,
:;: modulus of elas ti cit y o f concrete . MP,1. Sec SC'lion 208.6. 1 :;: modulus of elasticity of rcin f'o rcc m clH. MPa. Sec Sections 408 .6.2 and 408 .6.3 speci fied compressive strengt h of cOllc re te. Mila ;; speci fied yie ld strength of Ilo nprestn::ssed re inforce ment. MPa :;;: length of clear Sp:lH measured facc~ l o- fC!(:c of
r, :;: ~
I" V, Iii, IV"
fJ,
Slipp0 11 S. mill ;;: no m inal shear stre ngth provided by concrete :;: ullit weight of concrete, kghn ,l ;;: facLOrccl load per unit len gth of beam Or' per Llnit area o f slab = raCIOr defined in Seclion 410,3 ,7.]
P
in ex treme tens io n steel at nom inal strcng th ;:: w ti o or no nprcstressed ICllsion rcinrorcclllcnl
p'
= liJbd ;:: rati o or lIonprcsl rcssc cJ compression l'l.!inforL'cmclH
£,
408.3.3 In ~csig n for wind :111<1 c4l11hquakc loads, intcgraL structural pans shall be dcsigilCd to resist th e (otal lateral
loads, 408.3.4 Considerat ion sha ll be given to e ffcc ts or rorces due to prcstrcssing. crane loads , vihratio n, impac l, shrinkage , temperature changes. creep. expansion of shrinkageco mpcnsating C{) llcrC le tul d uneqllal settl cmcllt of supports.
408.4 Methods of Analysis 408.4.1 All members or ffum es or <.:o minll ous construction shall be designed (or tile ma ximulll effects or fa c tored loads as determined by th e th eory o f clastic 'IIln lysis, exc ept as modified by Section 408.5 , It sha l l be permincd to si mplify the design by usin g tilt:: nss ll ll1p ti olls spccilkd in Scction s 408 .8 th rough 408 .12.
;:: net tens ile stra in
= II ',1M Ph :::: rcinrorccmcnt
ratio
produci ng
condi li ol1s, Sec Sccl io ll..j
¢
408.3 ,2 Servi ce load s shall he in iH:corda nce with C hapter 2 or this code Wilh appropriatl.!. live IO
.:::: streng th -red uct ion rac tor.
halanced
~ tn li !l
IO .,~ .2
St' C
SCCl io1l409.4
408.4.2 Except fo r prest resse d concrct!.! , approximate me thod s or frallle anal ysis ma y bc lI sed for buildings of usual Iypes of construct ion , ~p a!ls .1Ilt! story he ig ht s.
408.4.3 As all a ltenlm!.! In fraillc illHlIY'iis, till' rollowi ng approxim.llc mOlllclltS and 'ihcar~ ~ h ;tll I ~ l>cnn ittcd (0 he used in t.Ic sign o r l' ()JlI i lltl(H1~ heam:.. and OIl!.! · ""';I)' '\1<1hs (~ I ahs reinforced to rc ~ is t Ikxllral :.. trcs,cs ill on ly olle directit)ll). provided:
I.
408.2 Design Methods
T here are two I)r mo rc
SPilIlS ;
lar~cr of two adj'll"l'nl SpilllS tl OI grcater than the shoneI' by more than :W pcn.:clll:
2. Spans 'arc :l)proxilll:ltcly equal. wil h lhe
•
408.2. 1 In dc~ign or stnH.:tural t'tHH:n.'te. mcmhe rs ~hall he proportioncd fo r <\(lcqlla!c ~Ircllg th in ;!(conl'lIll'e wi th pro visioll~ o f this C h a pl~f. using load f;K h )r~ and "tn'llgt hn.'(iLU,'li on r;lcl o r~ ~~srccificd ill Scn io ll -Hl9 , 40X.2.2 f)c~ign of reinrorced ClHllTl'!t' of Set'lillll 425 ~hall he pcnnillcd,
U'IIl)!
Ihe
I .();!d ~
-I .
U nfaclOrcd li ve IO
),
Melllhcr~
pm\'i,itl ll ~
40 H.2.J An<.: h llr~ wit hin the St'Olk ' II!' Set'ltlln ,n.\ 111'.. 1:111('(1 in (o nne h.' 10 I r: lII ~ kr l" ;,,ds !~I\vl'l'n rnll n l'~ t l' d Llt' l lIl'n " s ha ll he Ik:-. ig ned US III~ Sect ion ·123 .
.1 ,
arc Uillftll'lll i y d i ~ lril)llt ed :
arc prismalic
CHAPTI: R 4 . Concrete
For caJculming negative 1ll0IllCIHS, orthc
/"
is IiIkcn as the avcrage
POSITIVE MOMENT:
4·39
Stati c equi librium shall be maintained after redi stributi on of moments for each loadi ng arrangement 408.6 Modulus of Elasticity
End spans
408.6.1 Modulus of elasticit y E,. for concrete shall be permitt ed to be take n as w/sO.043 (in MPa) for
Discontinuous end unrestrained Disco ntinu ous end integral with
F,
.... wlIl,i'~1J4
SUppOI1
w J}1l6
Intelior spans
For values of Wr between 1.500 and 2,500 kg/ml. normal. weight co ncrete, Ec shall be permitlcd to be taken
1I
as 4700
.J"/':
NEGATIV E MOMENT: al
Two spans ................. .
\t
l
"I./19
w,.J,,'~/ IO
More than two spans .. at other faces of interior support s
1V.,/,/·!11 1
at face of all su pports for: slabs with sp:lnS not cxceeding 3 meters; and beams where ratio of su m of column sl iffnesses (0 beam stiffness exceeds cigh l at each end of lhe span
408.7.1 To account for the usc of liglHweight concrete, unless !:>pccifically noted otherwise, a modification factor ), w)}'124 w)}1!6
SHEAR :
at face of first interi or suppon .. .. . ... ..... face of all ot her slIppOJ1S . ...... ............
408.6.3 Modulus of elasticity Es for prest ressing tendons shall be dClcnnined by lc:-itS or supplied by the manufacturer. 408.7 Lightweight Concrete
al interior face of exterior support for members built integrally with suppons: where support is a spandrel beam where su pport is a column
a\
of elasticit y Es for nonprestressed reinforcement shall be permitted (0 be taken as 200,000 MPa.
408.6.2 Modulus
ex tcrior face of first intcrio r sllppon
1. 15 11',,1,/2 11',,/,,/2
408.4.4 Stru HlIld -tie models shall be penn illcd to be used in the design of slruclunll concrele. Sec Section 427. 408.5 Redi stribution of Negative l\1omcnts in Continuous Nonprestressed Flexural Members 408.5.1 Excep t where approximate va lue.. .c; for moments arc used. il is pe rm itted to decrease factored momcnts calculated by clas ti c thcory at sections of max.i mu m nega tive or positi ve momcnt in any span of contin uous fl exu ral mcmbers ror any ass umed loading arrangement by nOI morc than IOODE, percen t, wi th II maxim um of 20 percen!. 408.5.2 Hcdi stribu ti oll of negat ive moments shill I he madc only wh c n t.j is equal to or greater than 0.0075 H( the sec ti on at whi ch mome nt is reduced.
appears as a multiplier of
F,
in all applicable equations
and sections of this code, where }, = 0.85 for sandlightweight COllcrete and 0.75 for all-li ghtweight concrete. Linear interpolation between 0.75 and 0.85 shall be permitted, on the basis of volume tri c fracti ons, when a pOl1ion of the ligili weight fine agg regate is replaced with normal-weight fine aggregate. Linear interpolatio n between 0.85 and 1.0 shall be permitted, on the basis of volu mclric frac ti ons. for concrele con taini ng normal-weight fine aggregate and a blend of li giliweigh t and normal -weight coarse aggregates. For normal· weigh t conc rete, }. = 1.0. If average splitting tensile strength of li ght we ight concrete,Fe/> is specified, A ~ t" 1(0.56
F, .) $
1.0.
408.8 Stiffness 408.8. 1 Use of any set of reasonable assumptions shall be pCl'mitlcd fo r co mputing relati ve ncxu ral and torsional sliffnc!;scs of colu mns. walls. Ooors and roof sys tems. The
408.8.2 Effect of haunches shall be considered both in determining moments and in design of members.
408.5.3 The reduced IllOJllent shall be used for calcula ting redistribut ed moments at all other sections within the spans.
National Structural Corle of tl'l('; Pililippines 6
111
Edition Volumr? 1
4·40
CHAPTEI, 4 . Concrete
408.11 Columns 408.9 Effective Stiffness to Determine Lateral Deflections
408.9.1 Lateral deflections of reinforced concrete building systems resulting from service lateral loads shall be computed by either a linear analysis with member stiffness determined using 1.4 times the flexural stiffness defined in 408.9.2 and 408.9.3 <>1' by a more detailed analysis. Member properties shall not be taken greater than the gross section properties. 408.9.2 Lateral deflections of reinforced concrete building systems resulting from factored lateral loads shall be computed either by linear analysis with member stiffness defined by (I) or (2), or by a more detailed analysis considering the reduced stiffness of all members under the loading conditions: I.
By section properties defined in 410.12.3 (I) through (3); or
2.
50 percent of stiffness values based on gross section properties.
408.9.3 Where two-way slabs without beams are designated as part of the seismic-foree-resisting system, lateral deflections resulting from factored lateral loads shall be permitted to be computed by using linear analysis. The stiffness of slab members shall be defined by a model that is in substantial agreement with results of comprehensi ve tests and analysis and the stiffness of other frame members shall be as defined in Section 408.9.2.
408.11.1 Columns shall be designed to resist the axial forces from factored loads on all floors or roof and the maximum moment from factored loads on a single adjacent span of the floor or roof under cOllsideration. Loading condition giving the maximum ratio of moment to axial load shall also be considered. 408.11.2 In frames or continuous constl1lction, consideration shall be given to the effect of unbalanced floor or roof loads on both exterior and interior columns and of eccentric loading due to other causes. 408.11.3 In computing gravily load moments in columns, it shall be permitted to assume far ends of columns built integrally with the stl1lcture to be fixed. 408.11.4 Resistance to moments at any floor or roof level shall be provided by distributing the moment between columns immediately above and below the given floor in proportion to the relati ve column stiffnesses and conditions of restraint.
408.12 Arrangement of Live Load 408.12.1 It is permissible to assume that: l.
The live load is applied only to the floor or roof under consideration; and
2.
The far ends of columns built integrally with the structure are considered to be fixed.
408.10 Span Length
408.12.2 It is permitted to assume that the arrangement of live load is limited to combinations of:
408.10.1 Span length of members not built integrally with supports shall be considered the clear span plus depth of member, but need not exceed distance between centers of supports.
I.
Factored dead load on all spans with futl-factored live. load on two adjacent spans, and
2.
Factored dead load on all spans with full-factored live load on altemate spans.
408.10.2 In analysis of frames or continuous construction for determination of moments, span length shall be taken as the distance center to center of supports. 408.10.3 For beams built integrally with supports, design on the basis of m'()ments at faces of support shall be permitted.
408.10.4 It shall be permitted to analyze solid or ribbed slabs built integrally with supports, with clear spans not more than 3 111, as continuous slabs on knife edge supports with spans equal to the clear spans of the slab and width of beams otherwise neglected.
408.13 T·beam Construction 408.13.1 In T-beam construction, the flange and web shall be built int.egrally or otherwise effectively bonded together. 408.13.2 Width of slab effective as a T-beam flange shall not exceed olle-fourth the span length of the beam, and the effective overhanging slab width on each side of the web shall not exceed:
J.
Eight times the slab thickness; or
2.
One-half the clear distance to the next web.
Association of Structural Enginems of the Philippines
,f
CHAPTER 4 . Concrete
4-41
!
408.13.3 for beams with a slab on one side on ly. the effective overhanging flange width shall not exceed:
1,
Onc·twclfth the !span"length of the beam;
2.
Six limes the slab thickness; or
3.
Onc·halflhc clear di stance to the next web.
408.13.4 Isolated beams. in which Ihe T·shape is used 10 provide a flange for additional compression area, shall have a flan ge thickness not less than one half the width of web and an effective fl ange width not more th an four limes the width of web.
"
t
408.13.5 Where primary ' flexural reinforce ment in a slab that is considered as a T·beam flange (excluding joist cons tru ction) is paraliel to Ihe beam, reinforcement perpendicular 10 the beam shall be provided in tl,e lOP of tl,e slab in accordance with the following:
408.13.5.1 Transverse reinforcement sha ll be designed to carry the factored load on lhe overhang ing s lab widl.h assumed 10 act as a cantilever. For iso latcd beams. the full width of overhanging flange shall be considered. For other T-beams, only the effective overhanging slab width need be considered.
408.13.5.2 Transverse reinforcement shall be spaced not farther apart than five times the slab Ihickncss or 450 mill.
408.14.5.2 Slab thickness over permanent fillers shall nol be less than one twelfth the clear distance between ribs nor less than 40 mm. 408.14.5.3 In one-way joisls, rei nforcement normal to Ihe ribs shall be provided in the Slil b as required by Secti on· 407.13. 408.14.6 When removable forms or fil lers not complying with Seclion408. 14.5 are used: 408.14.6.1 Slab thickness shali not be less than one twelfth the clear distance between ribs, or less than 50 mm . 408.14.6.2 Reinforcement normal to the ribs shali be provided in the slab as required for flexure. considering load concentrations, if any, but not less than req uired by Section 407.13. 408.14.7 Where conduits or pipes as pcrmjlled by Section 406.3 are embedded within the slab. slab Ihickness s hall be al least 25 mm greater th an the total overall depth of the conduits or pipes at any poin!.. Conduits or pipes shall not impair sig nificantly the stre ngth of the cons truction. 408.14.8 For joist cons truction, contri bution of concrete to shear strengt h Vc- is permitted lO bc 10 percent morc than that specified in Section 411. It shall be peml ilted lO increase shear strength using s hear reinforcement or by widening Ihe ends of the ribs.
408.14 J oist Construction 408.14.1 Joist constmction consists of a mOllolilh ic combination of regularly spaced ribs and a top sJab arranged to span in one direction 01" two oI1hogonal directions. 408.14.2 Ribs shall not be less than 100 Jllln in width and shall have a depth of not more than three and one-half times the minimum width of rib. 408.14.3 Clear spacing between ribs shali nOl exceed 750
mm.
408.1 5 Separate Floor Finish 408.15.1 A floor finish shall not be included as pan of a strucwral member unless placed monolithically with the floor slab or designed in accordan ce with requiremen ts of Section 4 J 7. 408.15.2 It shall be permitted to consider all concrete floor finishes as part of required cover or tOlal thickness for nonslructural considerations.
408.14.4 Joi sl. constmclion not meeting the Iimitalions of Seclions 408.14. 1 Ihrough 408.14.3 shali be designed as slabs and bea ms. 408.14.5 When permanent burned c11l)' or conc rcte tilc fillers of J1lillcrial having a unit comp ressive slrenglh at least equal to that of the speci fied strength of co ncrete in the joists are used: 408.14.5.1 For shear and nega(ivc~momem strength computati ons. it shall be penniued to include the vertical shells of fillers in cont act with ribs. Other pOI1ions of ml eTs shall not be included in strength compu tations. Nationa l Structural Code of tl1e Philippines
6\11
Edition Volume 1
4-42
CHAPTER 4 - Concrete
p
nominal axial load strength at balanced ~>train co nditions. See SCClion 410.4.2 :: nominal ax ial load strength at given eccentricity =-rai n load, or related internal moments a!ld fo rces. Sec tion 409.3.1 :: cumulative effects of temperature, creep, shrinkage. d iffe renti al settlement and sh rinkage compensatin g concrete = requ ired strength to resist fa clOfcd loads or relate d internal moments and forces = w ind load, or re lated internal moments and forces 3 = weight of concrete. kg/m = distance from centroidal axis of gross section , neglecting rei nforcemelH, to ex.treme fiber in tension = ratio of flexural sti ffness of beam section to flexural stiffness of a width of slab bounded laterall y by center line of adjacent panel , if any. on each side o f beam . Sec Secti on 4 J 3 :: average value of Of for all beams on edges of a panel :: ratio of clear spans in 10ng~lo-sh ol1 direction of two-way s labs = time-dependent factor for sustained load. Sec Section 409.6. 2.5 = net tensile strain in ext reme tcnsion ste d at nominal strength modification factor rellec ling the rednccd mechani ca l properties of lightweight concrete. See Section 408.7. 1 = multipli er for additional l ong~t ime dei1cction as defined in Section 409.6.2.5 = ratio of nonp restressed tcns ion reinforcement,
p'
= rei nforcement rati o for no nprestressed compressio n
Ph
:: re inforcement ratio producing balanced strain
=
¢
= st rength -reducti on fa cto r. See Section 409.4
=
409.2 General
Pb
p. Ii 409.1 Notations At
A's b
c
2
:;:: gross area of secti on. mm :;:: area of compression reinforcement, mm 2 :;:: width of compression face of me mber, mOl = distan ce from extreme compression fiber to neutral
axis. mm D cI tI'
;::;: dead loads, or related internal moments and forces :;:: distance from ext reme compression fiber to centroid of tension rei nforcement, mrn :;:: distan ce from extreme compression fiber to
ds
:;::
tI,
:;::
£
=
Er
:;::
F
;::;:
fl.
=
T
u w y,
centroid of compression reinforcement, mm distance from extreme te ns ion fib er to centroid of tension reinforcement, mm distance from ex tre me compress ion tiber to extreme tension steel, mm load effeclS of earthquake, o r related internal moments and forces modulus of elasticity of concrete. MPa. See Section 408.6.1 loads due to weight and pressures of fluids with well defined densities and controllable maximum heights. or related internal moments and forces specified compressive strength of concrete, MPa
ff == square rom of specified f,
J; I-I
II
I,
I, L I
I"
1yI" M"
=
compressive strength of
co ncrete. MPa splitting tensile stre ngth of lightweight aggregate concrete, MPa = modulus of rupture of concrete, MPa :: specified yield strength of nonprestressed reinforcement , MPa :: loads due to weight and pressure of soi l, water in soi l, or ot her materials, or related in tern al mome nts and forces = overall thickness of membe r, mm moment of inerti a of cracked section trans formed to concrete. mrn~ effective mOlllent of inertia for co mputati on of delleclion, 1l11ll4 = moment of inertia of gross concrete seclion about 4 cClHroidal ax is. neglecting rein forcement, mm == Jive loads. or re lated in ternal moments and forces == span length o f beam o r one ~w a y s lab, as defined in Section 408 . 10; dear proj ec tion of cantilcver, mrn = length of clear span in long uirection of two-way construc tion, measured face to face of supports in slabs without beams and face to face of beams or o ther SUpp0l1S in olher cases =- maxim um moment in membe r at stage d eflection is comput ed = crack ing mOlllcnt. Sec Equation 409-9
= average
fJ
::
Ad
A/bd reinforcement, A 'jbd conditions. See Section 410.4 .2
409.2.1 Structures and structural members shall Iw (k~iJ ';! cd (0 have design strength s at all secti ons at !cil :-.i n;i:, ' required st rengths calculated for the faclOr.:,! hi: forces in such combinations as arc sti pulated in l his <.'< l(lc.
."
409.2.2 Members also sha ll meet all other requi remc nts of thi s code to e nsure adequate perfo rm ance al :lcrvi{ ( to ad levels. 409.2.3 Des ign of Slructures and stru c tural mClllbc'I",'\ Will i'. the load faclor combinali ons and st renglh r(' (b ':i '·.~' ";! (.;., . o f Section 426 shall be permiued . Usc ( l l" ;,;.,,,j ilt.:h.
Association of Structura l Engineers of the Philippines
CHAPTER 4 . Co ncrete
4·43
combinations [ rom this chapter in conjunction with st rengt h reduction factors of Section 426 shall not be permitted.
the appropriatc load combinations of ASCE I SEI 7 shall be used.
409.3 Required Strength
409.3.5 For post-tensioned anChorage zone des ign, a load factor of 1.2 shall be applied to the ma ximum tendon jackj ng force.
409.3.1 Rcquired SlrclIgth U shall be at least equal to the effects of factored load s ill Eq. 409- 1 through Eq . 409-7 . The effect of one or more loads not acting simultaneously shall be investigated.
U
=
1.4(D + F)
(409- 1)
U = L2 (D+ F + T) + 1.6 (L+H) + O.5(L. or R)
(409-2)
U = 1.2 D + 1.6 (L, or R) + (1.0L or 0.80 W)
(409 -3)
U = 1.2 D + 1.6 W + 1.0 L +O.S (L, or R)
(409-4)
U = 1.2 D + 1.0 E+ 1.0 L
(409-S )
409.4 Design Strength 409.4.1 Design strengtll prov ided by a member, its con necti o ns to other members and its cross sections, in terms of fl ex ure, a xial load, shear and torsio n, shall be take n as the nomi nal strengt h ca lcul ated in accorda nce with requiremen ts and assumptio ns of this Section, mult iplied by a s trength- reduction factor ¢ in Sections 409.4.2, 409.4.4 and 409.4.5. 409.4.2 Strength-Reduction Factor Strength-reduction factor ¢ shall be g iven in Sections 409.4.2. 1 through 409.4 .2.7 :
U = 0.9 D + 1.6 W + 1.6 Ii (409-7 )
409.4.2.1 Tension contro lled sections as defin ed in Secti on 410.4 .4 (scc also Scction 409.4.2.7) ............ .... .. .. . 0.90
I . The load factor on tile livc load L in Eq . 409-3 to 409-S
409.4.2.2 Compres sion co ntroll ed sections, as defi ned in Section 410.4.3:
U = 0.90 [) + 1.0 E + 1.6 Ii
except as follows: shall bc permitted to be reduced to 0.5 except for garages, areas occupied as places of public assembl y, 2 and all areas where L is greater th an 4.8 kN /m • 2.
\Vhere wind load W has not been reduced by a directionality factor. it shaH be permitted to use I.3 W in place of 1.6W in Eq. 409-4 and 409-6.
3.
W here E, the lo ad effects of earthquake. is bascd 011 ser vice-level seismic fo rces, 1.4£ shall be used in place of 1.0 E in Eq. 409-S and 409-7.
4.
The lo ad factor on H, loads due to weigh t and press ure of soil, wa ter in soil, or other materi al s, shall be set cqual to zero in Eq . 409-6 and 409-7 if the stmctural action due to H co unteracts that due to W or E. Where lateral earth press ure provides resi stan ce to structural ac tions from o ther forces, it shall not be included in Ii but sh all be includ ed in the design res istance.
409.3.2 If resistance to impact e ffects is laken into accouni in des ign, stich effects shall be included with live load L. . 409.3.3 Estimat io ns o f different ial settlement, creep. shrinkage , expansio n o f shrinkage-co mpe nsatin g conc rete or temperature change shall be based o n a reali stic assess ment of suc h effects occ urring in service. 409.3.4 If a structu re is in
1.
2.
Members with spiral reinfo rcement conforming to Secti on 4 10. 10.3 .. .... ..........
0.7S
Other reinforced 1l1cmbers
0.65
foo r sections in whi ch th e net tensile strength, Cr. is between th e limi ts for co mpressio n-controlled im d ten sio n-colHroll ed sectio ns, ¢ shall be pc nniucd 10 be linearl y increased from th at fo r co mpressio n-con tro ll ed sectiolls to 0 .90 as c, inc reases fro m the compression-cont ro ll ed strai n limit to 0.005 . Altern at ively, when Sec ti o n 425 is used, for mem bers in whi ch h' does not exceed 415 MPa, with s ymmetric reinforcement, and with (II . d')/h not less than 0.70, ¢ shall be permitt ed to be in creased linearly 10 0 .90 as ¢ P(l decreases from 0.10 fr A,( to zero. For other reinforced mem bers, ¢ shall he permi tt ed to be increased linearly to 0.90 as ¢ P., dec reases from 0. 10 AK or ¢ Ph, whic hever is smaller, 10 7.ero.
tc
409.4.2 .3 Shea r and torsio n (Sec also Section 409.4.4 for shear wn lls
th
National Structu ra l Code of th e P!)il ippines 6 Edition Volume 1
Wiles
085
~-4~
CHA I' TEI1 4 . Concrele
409.4.2.6 Slml·and-lie models (Secli on 427).
and struts, lics, llodaJ zones, and bearing areas in such models
0.75
409.4.2.7 Flexural sections in pre-tensioned members where
strand embedmen t is less than the development length as
409.5 Design Strength for Reinforcement The values of hand 11' used in design calculations shall not exceed 550 MPa, except for prestressing tendons and for transverse reinforcement in Section 410. 10.3 and 421 .3.5 .4.
provided in Seclion 412.10.1.1:
I,
Prom the end of the member to the end of the transfer .0.75
409.6 Control of Deflections
longlh ...
2.
From the end of the transfer length to the end of the devclopmcm length ¢ shall be permitted to be
409.6.1 Reinforced concrete members subject to lkxur('. shall be designed to have adequate stiffness to lim it deflections or any deformatio ns that adversely affect strength or serviceability of a st ructure.
linearly increased from .......................... 0.75 100.9 Where bonding of a strand docs not extend (0 the le:nd of the
member, strand embedment shall be assumed (0 begin at the end of Ihe debonded leng.h. Sec also Seclion 412.10.3. 409.4.3 Developmenl lenglhs specified in Sec. ion 4 12 do no! require a ¢ factor.
409.4.4 For structures that rely on intermediate precast structural walls in Seismic Zone 4, special moment frames, or special structural walls to resist earthquake e.ffccls. E, ¢shall be modified as given in Seclion 409.4.4.1 Ihrough 409.4.4.3: 409.4.4.1 For any structural member that is designed to resist E, ¢ for shear shall be 0.60 if the nominal shear strength of the member is less than the shear corresponding to Ihe deve lop ment of the nominal Ocxural st rength of the member. The nominal flexural strength shall be determined ' considering the most critical factored axial loads and including E;
409.6.2 One-Way Construction (Nonprestressed) 409.6.2. 1 Minimum thickness stipu laled in Table 409 : shall apply for one-way construction not supporting or attached to partitions or other construction likely to be. damaged by large deflections, unless computation of deflection indicates a lesser thickness Illay be used without adverse effects. 409.6.2.2 Where deflections are to be computed, deflections: that occur immediately on application of load sId! lv' computed by usual methods or formulas for e1as: ic deflections, considering effects of cracking i~nd reinforcement on member s tiffness. 409.6.2.3 Unless stiffness values arc obt:lined by a more co mprehensive analysis, immediate deflection shall :lC computed wilh the modulus of elasticity £c- fo r conc rete as specified in Section ·108.6. 1 (normnl ·wcight or ligh tweight concrete) and with the effective moment of incnia as follows , but not grefttcr than It:.
409.4.4.2 For diaphragms. ¢ for shear shall no. exceed the minimum ¢ for shear used for the vertical componen ts of the primary seismic-foree-resisting system; 409.4.4.3 For joints and diagonally reinforced coupling beams. ¢ forshear s hall be 0.85.
where:
M 409.4.5 Strength reduction factor ¢ for nexure, co mpression. shear find bearing of structural plain co ncrete in 'Secli o n 422 shall be 0.60. .
J, I , - - -)"
and for lIonn al-wcighl concrete
J, = 062}. ff,
Association of Structura l Eng ineers of the Philippin es
I I
i
CHAPTER 4 . Concrete
Table 409· 1 . Minimum Thickness of Nonprestrcssed Beams or One· Way Slabs Unless Deflections are Computed Minimum Thi ckness. It
Simply Supponcd
Member
One end
continuous
Both ends conrinuous
Can tilever
Members not supporting or auachcd to partitions or other construction likely to be damaged by large deneclion!i
Solid o"e· way slabs Beams or
_l
_e 24
_ t 28
_C
20
_ t 18.5
_ t 21
-1_
_ t 16
ri bbed one way slabs
10 8
Voluu gi1't~n shalJ 1M used directly for numbers wilh 11001101 weight COl/erne (w.. 2,400 I:glm 1 ) and Grade 415 reinforcement. Fo r other condirimlS, the mhus sholl be modified as/ollows: 0) For structural Ughnveighl concrete having !mit wtight ir! the rangt 1.500·2.000 kg.m ' , tilt values slutlf be multiplied by (1.65 . O.OOOJwrJ b/lf 110 1 Ius Ihan 1'(J9. whut! wf is the unit weight iI' kg/mI. /J) For h olher Ilion 4/5 MPa. Ihe ~'{Jlues shall be mulJipJied by (0.4 +
=
409.6.3 Two-Way Construction (Nonprestrcssed ) 409.6.3.1 1ltis sectio n shall govern the minimum thickness of slabs or other two-way constru ction designed in accordance with the provisions of Seclion 413 and confanning with the requirements of Section 4 13.7. 1.2. The thickness of slabs without interior bcall'lS spanning betwecn the suppon s on all sides shall satisfy the requirements of Section 409.6.3.2 or 409.6.3.4. Thickness of slabs WiU, bea ms spannin g between the suppo rts on all sides _shall sa tisfy the requirement s of Section 409.6.3 .3 or 409.6.3.4. 409.6.3.2 For slabs without interior beams spanni ng between the supports and having a ratio of long (0 short span not greater than 2, the minimum thickness shall be in accordance with the provisions of Table 409·3 and shall not be less than the following value.o;:
I . Slabs without drop panels as defi ned in Sections413.3.5 .............. ....... .................. 2.
//1001 409.6.2.4 For co ntinuous members, effective moment of inertia shall be pcnnitted to be taken as the average of values obtained from Eq. 409-8 for the critical positive and negative moment sec tions. For prismatic members, effective moment of inertia shall be permitted to be taken as the value obtained from Eq. 409-8 at midspan for si mple and continuous s pans, and at support for cantilevers.
For ll/rn equal to or less than 0.2, the provisions of Section 409.6.3 .2 shall apply.
2.
For /lfm greater than 0.2 but )10t greater th an 2.0. the thickness shall not be less Ih an: h=
12 months
................. 2.0
................................. 1.4
6 months
............... ............ 1.2
J mon,hs
............... .......... .. . I .0
(409· 12)
For llfrn greater Ihan 2.0, the thickness shall not be Jess than :
+..i.L)
I (0.8 • 1400 " = -'--:-3-:-6-+-':9-':p;-:-L
where p' shall be the value at midspan for simple and continuous spans, and at su pport for cantil evers. :It is permi ttcd to assume the time-dependent factor ~ for sustained lands to be equal to:
5 years or Illore
I. (OR+ "'&'-) 36+5P(a- ",, - O.2)·14()()
and not Jess than 125 111m .;
(409- 11 )
• - 1+50p'
Slabs with drop panels as defi ned in Sections 413.3.5 .......... .............................. 100 mOl
1.
3.
- -q-
125 mm
409.6.3.3 For slabs wilh beams spanning between the sllppons on all sides, the mjnimum thickness shall be as follows:
409.6.2.5 Unless values are obtained by a more comprehensive analysis, additional longtime denect ion resu lting from creep and shrinkage of flexural members (nonnal -weight or lightweight concrete) shall be determined by multiplying the immediate denec li on caused by Ihe sllstained load considered. by the facmr Ail •
A.
4· 45
(409·13)
and not less than 90 mill .
4.
At discontinuous edges, ~U1 edge beam shall be provided wi th a stiffness ratio Of", not Jess than 0 .80; or the minimum thickness required by E. .!. 409- 12 or 409- J3 shall be in creased by at !C,lst J{) percent in the panel wi th a discontillllow; edge.
409.6.2.6 Defl ection co mputcd in accordance with Scclions 409.6.2.2 th rough 409.6.2.5 shall not exceed Ii mits stipulated in Table 409·2.
t1l
National Structoral Code of the Philippines 6 Edition Volume 1
4·46
CHAPTER 4 . Concre te
Table 409-2 - Maximum Pennissible Computed Defl ections Type of Member
Deflection 10 be cons idered
Deflection Limitalion
Table 409-3 - Minimum Thickness of Slabs
wit hout Tnterior Beams Yield stre ngll!
._--_._._------
!, MPa
Flat roofs not supportin g or att ached
to nOIl-stnl c[ural elements likely to be damaged by large deflections Floors not support ing or all ached (0 nOll-
Slniclural elemen ts likely (0 be damaged by l afl~e
Immediate defl ection due (0 live lomJ, L
_,_' 180
280 415
immediate deflection due to Jive load. L
~ 360
520
deflections
Roof or floor construction supporting or allached 10 lI on~ struclum l elcments likel y 10 be damaged by larJ!c dcflecl ions Floor or fl oor constmcti oll sll PPor1 in g or attached to nOIl structural cl ements not likcly 10 be damaged by larne defle cti ons
That part of the totnl defl ection occurring afler aHachmcnl of nonslfUclUral clemenIS (sum of the long-term defl ection du e to all sustained loads and lhe immediate deflecti on
duc to any additi onal live load) }
With drop panels2
Wi thout drop panels'
i
Exteri or panels
Inte rior
panels
E)(tcrior panels
Interior
-~
without edge
With edge
beam
beam'
~
~
~
~
36
36
40
~
~
~
~
-~
33
33
33
36
36
~
~
~
~
~
31
31
31
34
.£.....
28
without
with
edge beam
edge be:lIn
~
~
33
36
~ 30
40
34
~ 480
For W11ll~.s of ubJjor'amerli yield strength b~ nyt:~n the I'(llues given ill table, minimum tMckn ~ss .shall b, det~n"i"ed by /incar imerpoiation. 1 Drop pOllels i.s deft/Jed ill 4 / 3.3.5. ) Slab.s with bcarlu benytcfI co/umlls along exterior edg~s. The mlue of a fOr' Ille edge beam shaff /lOt be less 1"011 0 .8.
-240'-'
Tenn I" in (2) and (3 ) is length of cl ear span in long direction measured face -to~face of beams . Term fJ in (2) and (3) is ratio of clear spans in long to short direction of slab.
I
Limif flO / illl~ rlfl(!(1 /() sajegmm l againsl pOllding. POllding .should be checked by sui/able C(l /c II /alioris of dC'fll'c /iotl, incllldillg addc(/ til'jleclioru due to ponded WOler, and cOllsiderillg 100lg·tentl effects of all su.staifll'd loads. camber, camtnlc{iol/ w{crar/ces. alld reliabiliry of pTlll'i.siOI/S for dminnge. 1 Lollg temr dcj7~rtimr slrafillt' dell'nniMd irl (l (('o rdmrC(' with 409.6.2.J or 409.6.4 3. bill 1110)' hl' reduced by (11110/1111 of defll'ction ca/culatl'd W OCC/lr lu,/ore all(lci!mcnf 0f11OIIs/ructural c/~mC'/lIS. T1r~ omOUIII.rlwl/ b(' dete17l1illc(1 (III bilsi.f oj (lccepfC'd cII,I;il1urillg t/m(l re/millK to time · dcjkclimr dwnWlcri.\·IIC.f of IIIemlu!rs xill/iltlr f() Ihast' brillK cmr.{il/erc'(i. limit may 1)/.0 ('XC('c'cJce/ if adequ(l/C rlll.'lI.U/rcs {ITt' ,aJ:e" In P"' I'('1I1 damage ((J slippon('(1 or (lllacireel delllC'lIfs. 8 11t 1101 greate, tium tolerallce "ravil/cd Jor lIflt/sl rUClUra l cJC'IIICfIf.{. l.imil may be cxl'('cdcd if camber i ... t'ml'/'dr~d .m 111m tolal t1('-fI/~c:fi(1n millie; ca mhrrt/o(!S 1I 0 1 1'xcn~d limil.
Ihe
409.6.3.4 Slab thickn ess less than th e minim um thickness requ ired by Sections 409.6.3.1 . 409.6.3.2 and 409.6.3.3 sha ll be pe rmitted LO be used if shown by computation that the deOccf io n will fl ot exceed the limits stipu lated in Table 409 -2. De flections shall be co mputed taking into acco unt size and shape of the panel. conditions of support. and na ture of restraints at the panel edges. The mod ulus of elastic it y of co ncrete E( sha ll be as specified in Section 408.6. 1. The effec ti ve moment of inertia shall be that given by Eq. 409-8; other values s hall be permilled to be used if they resull in computed de fl ections in reasonab le agreement with the resu lts of compre he nsive tests. Add itional lo ng te rm defl ecti on s hall be computed in accord ance with Section 409.6.2.5 . 409.6.4 Prestressed Concrete Construction 409.6.4.1 For fl exu ral me mbers designed in accorda nce with provisions o f Secti on 41 8. immedi a te de fl ection shall he co mputed by lI sual met hods or form ulas for elastic deflecti olls, a nd the momen t o f ine rt ia of the gross co ncrete section, I, . shall be perm itted to be used fo r C lass U flexura l members. , as defin ed in Sections 4 18.4.3.
409.6.4.2 For C lass C and Class T flexural members, a.' defi ned ill Section 41 8.4.3, dcflecti on calcul ations shall he based o n .a crac ked trans fonned secti on 3lWl ysis. 1t shall he perrniUcd to base comput ati ons on a bilinear Illomenl ·· dcn eclion relationshi p, or an effecti ve mo ment of inel1ia, le , as defined by Eq. 409· 8. Assoc iat ion of Structu ra l Enginee rs of the Pllil ippines
CHAPTER 4 . Concrete
409.6.4.3 Addit ional long-time deflection o f prcstressed concrete members shall be computed taking into accoun t stresses in concrete and steel under sustained load and includi ng effects of creep and shrin kage of concrete and relaxation of steel.
I
I
409.6.4.4 Deflection computed in accorda nce with Secti ons 409.6.4. 1, 409.6.4.2, and 409.6.4.3 sha1l no. exceed limi ts stipulated in Tablo 409-2.
410.1 Notations
A Ach
!
i
409.6.5 Composite Construction 409.6.5.1 Shored Construc tion
If composite nexural members are supported during construction so that, after removal of temporary supports, dead load is resisted by the full composite section, it shall be pennitted (0 consider the composite member equivalent to a monolithically cast member for computation of deflection . For non prestressed members, Ule portion of the member in compression shall determine whet he r value.~ in Tab le 409-1 for normal-weight or lightweight concrete s hall apply. If deflection is computed, account shall be taken of curvatures resulting from differential shrinkage of precast and cas t-in place components, and of axial creep effec ts in a prestressed co ncrete member.
4-47
Ag As II .J.min
AH An
A, AI A2
:::: depth of equivalent rectangu lar stress block as defined in 5oc.ioI1410.3.7.1, mm = cross-sectional area of a slmctural member measured to ou tside edges of transverse reinforcement, mm2 ::::= gross area of section, 111m2 ::: area of non prestressed longitudinal tension rei nforcement, mm 2 =m.·nimum amount of nex ural reinforcemen t, mm 2. See Sec.ion 410.6 :;::;area of structural steel shape, pipe, or tu bing in composi te section, mm 2 . See Section 410.17.5 ~total area of nonpres tressed longitudinal 2 reinforcement (bars or steel shapes), mm ::::= area of structural stee l shape, pipe or tubing in a composite section, 111m2 ~ loaded area, 111m 2 = the area of the lower base of the largest frustum of a pyramid, cone, or tapered wedge contained wholly wi.hin .hc support and having for its uppcr base the loaded area, and having side slopes of I unit vertical in 2 units horizontal (50% slope), 2
409.6.5.2 Unshor ed Const ruction If the thiclOlCSS of a nonprestresscd precast nexuraJ member meets the requirements o f Table 409-1, de nection need not be computed. I f (he th ickness of a no npreslressed composite member meets the requirements of Table 409 -1, it is not required to compute deflection occurri ng aflcr the member beco mes co mposite, bu t the long-time dCnecliol1 of the precast me mber simI! be investigated for magnitude and duration of load prior 10 beginning of effecti ve composite action.
b
;:;
bo..
;::
c
"" ;::
Coo d
409.6.5.3 Deflecli oll computed in accordance with Sections 409.6.5. 1, or 409 .6.5.2 shal l not exceed limits stipula.ed in Table 409-2.
d,
E( E
j
1:.."1
f(
h 1;., h
mm w idth of compression face of member, mill web width , mill distance from extreme compression fiber to neutral axis, mm clear cover from the nearest surface in ten sion to the surface o f the nexural ten sion reinforcement ,
mrn ::; a factor relating actual moment diagram to an equivalent uniform momelll diagram ::; distance from extreme compression fiber to centroid of tension reinforcement, mill = thickness of concrete cover measu red frolll extreme tension fib er to center of bar or wire located closest thereto, mm ::; distance from extreme compression fiber to extreme tension steel, mm :;:: modulus of clasti city of concrete, MPa == modulus of elasticity of reinforcemen t. MPa ::; n ex ural s ti ffncss of compression member. N_mm 2 Sce Eq. 410·15 illld 410-16 = specified compressive slrenglh o f concret.e, MPa ::; ca lculated stress in reinforcement at service load s, MPa = spccified yield strength f,. of tran:..vcrsed reinforcement , MPa = overall dimcnsion o f me mber in dirccti on ac tio n co ns idered , mm
or
11l
National Structural Code of th e Philippines 6 Edition Volum e 1
4·48
CHAPTER 4 . Concrete
:: moment of inenia of gross concrete secti on about 4
I" I"
k
ccntroidal axis, neglecting reinforcement, mm ::= moment of inertia of reinforcement about ccnlroidaJ axis of member cross section. mm 4 = moment of incI1ia of stl1Jctural sleel shape, pipe or tubin g about ccnlroidaJ axis of composite member cross secl.i on, mm~ ;;: effective length factor for co mpression members :: length of a compression member in a fram e, measured from center to ccnter of the joints in th e
A1(
frame ;; unsupported length of compress ion member, mill. ;: factored mo ment to be used for design of
M,
= moment due to loads causing app reciabJe sway
M..
;; factored momenl at section
MI
= smaller factored end moment on a compression member, positive if member is bent in single curvature, negative if bent in double curvature = faclOrcd end moment on a compression member at the end at wh ich M J acts, due to loads that cause no apprcciable sidesway. calcul atcd using a first-order clastic frame analysis = fn ctored end moment on co mpression members at the end at which M/ acts, duc to loads thm cause appreciable sides way, calculated using a first-order elastic frame analysis = larger factored end moment on compression member. always positive = minimum value of M l = factored end mome nt on compression member at the end at which M2 acts. due to loads that cause no appreciable sidesway, calculated using a first -order elastic frame analysis = factored end moment on co mpression member ill Ihe end at which M2 aCIS, due 10 loads thtlt cnuse ;:Ippreciable sides way, calculated usi ng a first-order elasti c frame ana lysis = nominal axial load strength at balanced strai n co nditions. Sec Section 410.4 .2 = critical load. Sec Eq. 410-14 = nomina! nxialload strength at given ecccntricity = nominal axial load strength at ze ro eccentri cit y = factored axial load at given eccentricit y
1/1
P, PdllJ
Lt"
compression member
M /lu
M IJ
Ml
M Vrlill M 2/tJ
M21
PI!
P, PI! PrJ PI'
.s (J P
II
Q
,.
V"_~
l
= stability index for a slory. See Section 4 I O. I 2.4 .2 = radius of gyrati on of cros:-; secti on of a compression member = maximum ccnter-to-centcr spacing of fl cxur;t1 tensioTl reinforcement nearest to the extreme tension face. mm (where thcre is onl y one hal' or wire neares! 10 the extreme tension face. s i!oi the maxi mum width of the extrcme tension face .) = factored horizontal shear in a story. N = quantity limiting di stribution of fl exural re inforcement. See Section 4 10.7
p
p,
= factor defined in Section 410.3.7.3
= ratio used to accoun t fo r reduction of stiffness of columns due to sustained axial loads = ratio used to account for reducti on of stiffness of columns due to sustained lateral loads = relative lateral denection between the top and bottom of a story due to V,,, computed using a firstorder clasti c frame ana lysis and stiffn ess values satisfying Section 410. I 2.4 .2 = momcnt magnification [..1. . . 101' for frames braced against sidesway (0 reflect effccts of member curvature between ends of co mpression members = moment magnification factor for frames not braced against sidesway to reflect laternl drift resU lting from lateral and gravity loads = net tensile strain in extreme tension steel at nominal strength = ralia of nonprestressed tension reinforcemcnt = A/bd = reinforcement ratio producing balanced strain conditions. Sce Secti on 410.4.2 = ratio of vo lume of spiral reinforcement to total volume of core (out-la-out of spirals) of a spirally reinforced co mpression member = strength-reduction factor. Sec Section 409.4 == stiffness reducti on factor
410.2 Scope
Provisions of Section 4 10 shall appl y for design of members subject to flexure or axial loads or to combi ned flexure and axial loads. 410.3 Design Ass umptions 410.3.1 Strength design of members for flexure and axial
loads shall be based on assu mptions
giv~~11
;n Sections
410.3.2 through 410.3.7 and on satisfacti on of applicable
co nditions of equilibrium and compatibility of strains. 410.3.2 Strain in reinforcement and COl1crete shall be
assumed directly proportional to the disI;uwe from the neutral axis, except that , for deep fl exural IJi' ;U H ,'.'; 'ok, ·;-; ~~d in Section 4 10.8. 1. an analys is th at con,,!,! distribution of strai n shall be used. A hern :;;,' · l · i .''''permitted 10 use a strut-and-t i::: model. See :)Cl.IHlIt . • hU~. 4 11.9. and Section 427 . 410.3.3 Maximum usable strain at cxtJ't'!lU' co mpression fiber shall be assumed equal "('; ~ .. :.
Association of Structural Engineers of the Pililippin es
'l h . .
rete
CHAPTER 4 - Concrete
410.3.4 Stress in reinforcement be low speci fied yield strength Ir for gmde of reinforcement used shall be taken as t"s times steel strain. For strains greater than that conesponding to h" stress ill reinforcement shall be cons idered indcpendem of strain and equal to1;.. 410.3.5 Tensile strengt h o f concrete sha ll be neglecp.ed in axial and flexural calculation s of reinforced concre te , except where meeting requirements of Section 418.5.
I
I
II
410.3.6 The relationship between concrete compressive stress distribution and <.:onc rCle strain shall be assumed to be rectangular, trapezoidal, parabolic or any other shape that resull s in prediction of strength jn substantial agreement with resu lts of comprehensive lests.
4·49
conditions, For Grade 415 reinforce ment, and for all prestressed reinforcement, it shall be permitted to set the compression-controlled st rain limit equal to 0.002.
410.4.4 Sections arc tension-controlled if the net tensile strain in the extreme tension sleel, et, is equal to or greater than 0.005 when the conc rete in compression reaches its assumed strai n limit of 0 .003. Sections with t( between the compression -controll ed strain limit and 0.005 constitute a transition region between compress ion-contro lled and tension-colltrolled secii,)ns. 4]0.4.5 For nonpreslressed flexural members and nonprestressed members with factored axial compressive load less Ihan 0.1 Of,' A" e, at nominal sirength shall not be
less Ihan 0.004. 410.3.7
Requirements or Seclion
410.3.6 may be
considered satisfied by an equivalent recta ngular concrete stress distribution defined by the following:
410.4.5.1 Use or compression reinrorcemenl shaJJ be permitted in conjunction with additional ten sion re inforcemenllO increase the strength of flexural members.
410.3.7.1 Concrete Slress of 0.85[, shall be ass umed unjfofJ1l1 y distributed over an equivalent compression zone bounded by edges of the cross section and a straight line located parallel to the neutral axis at a dis tance a:: (3, c from the fiber of maximum compressive strain. 410.3.7.2 Distance from fiber of maximum strain to the neutral axis. c, shall be measured in a dire:ction perpendicular LO the axis.
410.4 .6 Design axial load strength ¢Pn of compression members shall not be taken greater than the following :
410.4.6.1
For nonprestressed members with sp iral reinforcement confonning to Section 407.11.4 or composite members conforming to Section 410.17 :
(410- 1)
410.3.7.3 Faelor P, shall be laken as 0.85 ror eoncrele strengths!, for 17 MPa up 10 28 MPa. For siren glhs "bove 28 MPa. P, sliall be reduced linearly al a rate of 0.05 ror each 7 MPa of strength in excess of 28 MPa, but (31 s hall not
410.4.6.2 For nonprestressed members reinforcement conformin g to Section 407. 11.5:
be takcn less than 0.65.
410.4,6.3 For prestressed members. design ax ial load stren gth. riP" shall not be taken grea ter than 0.85 (for members with spiral reinfo rcement) or 0.80 (for members with lie reinforcement) of the design axial load strength at zero eccentricity. ¢' Po.
410.4 General Principles and Requirements 410.4.1 Design of cross scction subjeci to flexure or axial loads or to combined flexure and axial loads shaH be based on stress and strain compat ibi lity using assumpt ions in
Seclion 410.3. 410.4.2 Balanced st rain conditions exi~t at a cross section when tension reinforcement reaches the strain corresponding to its specified yield strengt h f. just as con crete in compression reaches it s assumed ultinlat c strai n of 0.003 .
¢/~ (mwl =
0.80¢[0.85[, (A,- A,,) +
with
tie
/,A"j (4 10-2)
410.4.7 Members subjecllo compressive axial load shall be designed for the maximum moment that can accompany th e axial load. The factored axial load PII at given eccentricity shall not exceed that given in Section 410.4.6. The maximum factored moment Mu shall be magnified for slende rn ess effecls in accordance with Section 410 .11 .
410.5 Distance between Lateral Supports of Flexural Members
410.4.3 Sect io ns IIrc compression·co lltrolietl if the ne t tensile strai n in the extremc tensioll slee l, t:/. is equa l 10 or les s thall the compression-controlled strain limit when th e concrete in comprcssion re;\ches its assullled strain limit of 0.003. The co mpress io n-controlled s t r~ jn limit is the: net tensile strain ill the reinforcement at balanced stra in
410.5.1 Spacing of laleral slIppons ror a beam shall nol exceed 50 times b, the least width of compression fl ange or fa ce.
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National Str.uctural Cod e of the Philippines 6 Edilion Volume 1
4-50
CHAPTEI1 4 .. Concrete
410.5.2 Effects of lateral eccentricity of load shall be taken into account in determining spacing of lateral supports.
410.6 Minimum Reinforcement of Flexural Members 410.6.1 At every section of a flexural member where (ensile reinforcement is required by analysis, except as provided in Sections 410.6.2. 410.6.3 and 410.6.4. A. provided shall not be less than that given by: A
.,min
=
.J4 /"/y
b d
(410-3)
W
and not less than 1.4 bwdl/y 410.6.2 For a statically determinate T-section with flange in tension, the area As,min shall be equal to or greater than the smaller value given either by:
A.,mln
rr:
= 2/
y
b.d "
(410-4)
or Eq. 410-3, except that b", is replaced by either 2 b", or the width of the flange, whichever is smaller. 410.6.3 TIle requirements of Sections 410.6.1 and 410.6.2 need not be applied if at every section, As provided is at least onc-third greater than that required by analysis. 410.6.4 For structural slabs and footings of uniform thickness, the minimum area of tensile reinforcement in the direction of span shall be the same as that required by Section 407.13.2.1. Maximum spacing of this reinforcement shall not exceed the lesser of three limes the thickness, nor 450 Illlll. 410.6.5 In structures located at areas of low levei seismic risk, beams in ordinary moment frames forming part of the seismic~force~resisting system shall have at least two main flexural reinforcing bars continuously top and bottom throughout the beam and continuous through or developed within exteriur columns or boundary elements. 410.7 Distribution of Flexural Reinforcement in Bemus and One-way Slabs 410.7.1 flexural and in stresses
This section prescribes rules for distribution of reinforcement to control flexural cracking in beams one-way slabs (slabs reinforced to resist flexural in only one direction).
410.7.2 Distribution of flexural reinforcement in two-way slabs shall be as required by Section 413.4.
410.7.3 Flexural tension reinforcement shall be well distributed within maximum flexural tension zones of a member cross section as required by Section 410.7.4. 410.7.4 The spacing s of reinforcement closest to a surface in tcnsion, s, shall not cxceed that given by:
(410-5)
but not greater than 300(2801/.). where co· is the least distance from surface of reinforcement or prestressing steelto the tension face. If there is only one bar or wire nearest to the extreme tension face, s used in Eq. 410-5 is the width of the extreme tension face. Calculated stress in reinforcement Is in MPa closest to the tension face shall be computed based on the unfactored moment. It shall be pennitted to take Is 'as 2/3 of specified yield strength J,.. 410.7.5 Provisions of Section 410.7.4 are not sufficient for structures subject to very aggressive exposure or designed to be watertight. For such structures, special investigations and precautions are required. 410.7.6 Where flanges of T-beam construction are in tension, part of the flexural tension reinforcement shall be distributed over an effective flange width as defined in Section 408.12, or a width equal to ~:)Ile-tenth the span, whichever is smaller. If the effective flange width exceeds Olle tenth the span, some longitudinal reinforcement shall be provided in the outer portions of the flange. 410.7.7 Where II of a beam or joist exceeds 900 mm, longitudinal skin reinforcement shall be unirorm~y distributed along both side faces of the member. Skm reinforcement shall extend for a distance hl2 from the tension face. The spacing s shall be as provided in Section 410.7.4, where Cn is the least distance from the surface of the skin reinforcement or prestressing tendons to tbe side face. It shall be permitted to include such reinforcement in strength computations if a strain compatibility analysi:: is made to determine stresses in the individual bars or wires.
410.8 Deep Beams 410.8.1 Deep beams are members loaded on olle face and supported on the opposite face so that compression slruls can develop between the loads and the supports, and Ii::':{ either:
Association of Structural Engineers of tl"18 Philippines
CHAPTER 4 - Concrete
I.
Clear spans, J", equal to or less than four times the overall member depth; or
2.
Regions wi th concen trated loads withi n (wice the member depth from (he face of the support.
Deep beams shall be designed either taking in to account nonlinear dist ri buti on of strain, or by Sectio n 427. (See al so Section 411 .9. land 4 12. 11.6). Lat eral buc klin g shall be co nsidered.
4W.8.2 VII of deep hi.:!ams shall be in accordance with Section 4 11.9. 410.8.3 Mi nimum nexural (ension reinforcemcnt, AI. shall confonn to Section 410.6.
min.
410.8.4 Minimum horizontal and vert ical reinforcement in the side faces of deep flexural members shall be the greater of the requirements of Sections 411.9.4. 4 11.9.5 and 427.3.3.
4-5 t
area. This provision shall not apply to special moment frames or special stlllctural walls in Seismic Zone 4 that are designed in accordance with Section 42 1. 410.10 Limits for Reinfor cement of Compression M emb ers 410.10.1 Area of 10ngituainaJ reinforcement, All! for noncomposit e compression members shall not be less than 0.01 or morc than 0.08 times gross area Ag of secti on. 41 0.10.2 Mini mum nu mber of longi tudinal bars in compression members shall be 4 fo r bars wi thin rectangul ar or ci rcu lar ties. 3 for bars witltin triangu lar ties. and 6 for bars enclosed by spirals conforming to Section 4 10. 10.3. 410.10.3 Volumetric spiral reinforcemen t ratio, be less than the value gi ven by:
Ps. shall not (41 0-6)
410.9 Des ign Dimensions for Compression Mcmbers 410.9.1 Isolated Compression Member with Multiple Spirals
Ou ter limits of the effective cross section of a compression mem ber with Iwo or morc interlocki ng spirals shall be taken at a distance outside (he ext reme limi ts of the spi rals equal
to the mini mum concrete cover required by Section 407.8.
410.9.2 Com p ressio n M ember Built Monoli thi cally With W a ll Outer limits o f the effective cross section of a spirally rei nfo rced or tied reinforced compression member built mo no lithicall y w ith a concrete wall or pier shall be taken not greater than 40 nun outs ide the spiral or tie rei nfo rcement.
where the value of /,., used in Eq. 410-6 shall not exceed 700 MPa. For /" greater th an 415 MPa, lap splices acco rdin g to Section 407. 11.4.5 (1 ) shall not be used. 410.11 Slenderness E lTccl< in Compression M embers 410.11.1 Slenderness effeclS shal l be pemli ucd to be ncglected in lhe following cases: I.
For compression members not braced against sidesway when:
k1u < 22 2.
For compression members braced agains t sides way when: 34 - 12( ; : ) :540
410.9.3 Equivalent C ircular Compression M ember
As an alternative to usi ng the full gross area for des ign of a com press ive member with a square. octagonal or other shaped cross section. it sh'llI be permitted to usc a ci rcu lar secti o n with a diameter cqual to the least latera l d imension of the actual s h~i;C . Gross area considered, requi red percen tage of reinfu rcemen t, and design strength shall be based on that circular section. 410.9.4 Limits ofSec tioll For a compression member with
(410-7)
r
(410-8)
where MIIM2 is positive if the colu mn is bent in single curvatu re. and negative if the member is bent in double . curvature.
It shall be pcmlitled to co nsider compression members braced against sideway when bracing elements have a total sti ffn ess, resisting lateral movement of that story. of at least 12 times the gross stiffness resisting lateral movement of that story. of at leas t 12 times the gross stiffness of the colu mns wit hin (he story.
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Nati ona l Structura l Code of th e Pll i1 ippines G Edition Volume 1
4.52
CHAPTER 4 . Concrete
410.11.1.1 The unsu pported length of a compression l11~cm be r . lu. shall be taken as the cJc
410.11.2 When s lenderness effects arc not negl ec ted as permitted by Sec tion 41 0. 11.1. the design of com pression mem bers. restrai ning beams, and other slipPol1ing members shall be based on the factored forces and moment s from a second -order analysis satisfying Sections 4 10. 1 J .3, 41 0. 11.4, or 410.11.5 . These members shall also sati sfy Sections 410.11.2.1 and 410.11.2.2. The dimensions o f each member cross section used in the analysis shall be within 10 percent of the dimensions of the members shown on th e design drawings or the analysis shall be repealed. 410.11.2.1 Total moment including second·ord er effects in co mpression members , restraining beams, or oth er structu ral members shall not ex ceed 1.4 times the moment d ue to firs t ~ order effects. 410.11.2.2 Second·order effec ts shall be conside red along the length o f compression members. It shall be pe rmitl ed to accouOl for th ese e ffects using the momc nt magnifica tion procedure out li ned in Secti on 4 10.13 . .
410.12.3 It shall be permined to usc the fo ll owin g properti es for the members in the structure: I. Modu lus of el ast icity ................ Er from Section 408.6.1 2. Moments o f inertia, J Compression members: Coiulnns ........... ..... ....... .. ....... ................... . Walls Uncracked. .. ...... ........ .... ........... .. Walls Cracked .
0.701, 0.701, 0.3 51,
Flexu ral members: BeaITIs ...... .. ....... ..... . Flat plates and fla t s labs ... ......... ..... .
3. Area ......................... ......... ...... ......... .
0.35/, 0.25 1.
LOOA,
Altem alively, the moment s of ineni:l of compression and fl exural members. I , sha ll be permitted to be com puted as follows: Compress ion members: 1 = ( 0.80+ 25A,, )( 1 -
M.. . 0.501:" j
/. S 0.875 I,
(410·9)
P"I!
Where Pu. and Mu. shall be det ermined from fhe pallicular load combination under co nsiderati on, or the comhillation of Pit and Mu. resulting in the smallest value of I. J need !lot be taken less than 0.35/,. Flexural members:
1 = (0.10 + 25p)( 1.2 - 0.2 b•.) 1,:0 0.5/,
(~ 1 0· 1O )
d f or cont inuous flexura l members. I shall be permillcd to be taken as the average of values obtained from Eq. I~ 10· 10 for lhe critical posi tive and nega tive moment scctions. J lIeeo not be taken less than 0.25 /, .
410.12 Magnified Moments 410.12.1 Nonlinear Second-Order Analysis Seco nd-o rder ana lys is shall cons id ermaterial on linearity, member curva ture an d lateral drift, du ration of loads, shri nkage and crecp. and interac ti on wilh Ihe sopporti ng found ation. The analys is proccdure shall have been shown [0 result in prediction of streng th in substant iil l a.grcemcilt with resu lts o f co mprehe ns ive tes ts of co lu mns in sta ticall y indelcn nin ate reillforceu concrete structures.
The cross~sect iolla l dimensions and reinforcement r~fio used in the above form ul as shall be within 10 pr nT!:1 d :hc d imensio ns and re inforcement ra tio shown on ! h t: de i t;l i drawings or the stiffness evaluati on shall be rcpc'llt:
410.12.2 Elastic Second·Order Analys is Elasti c sct:o n d ~ o rd er analysis s hall cons ider section propert ies det ermin ed taking into account th e infl uence of ax ial loads. the presence of cracked regi ons along th e le ngth o f th e member, and the effects of load durati oll .
410.12.4 I\:lomcnt Magnification I'roccdu l"!' Co lumns and stori es in structures shall be no ns way or sway columns or stori es. The dl',,, i: I: "j in nonsway frames or stori es s hall be based ,iIi
Association of Structural Enninecrs of the Philippin e:;
( ;,~ ; ::; .. ,1"\;0,;
CHAPTER 4 . Concrete
410.13. The design of columns in sway frames or stories shall be based on Section 410.14.
4·53
410.13.1.3 The effective length factor. k, shall be permitted to be taken as 1.0.
410.12.4.1 It shall be permitted to assume a column in a structure is nons way if the increase in column end moments due to second-order effects docs not exceed 5 percent of the first-order end moments.
410.13.1.4 For members without transverse loads between supports, c'1I shall be taken as:
assume a story
where M,IM 2 is positive if the column is bent in single curvature, and negative if the mem.ber is bent in double curvature. For members with transverse loads between supports, e", shall be taken as l.0.
410.12.4.2 It also shall be permitted within H structure is nons way if:
to
Cm
=
0.6 + 0.4 (M/M,)
(410·17)
(410·1 I) 410.13.1.5 The factored moment M, in Equation (410·12)
shall not be taken less than is less than or equal to 0.05, where ,[P" and Vus arc the total vertical load and the story shear, respectively, in the story in question and Lto is the first-order relative deflection between the top and boltom of that story due to V,,~. 410.13 Moment Magnification PnlceduJ'c - Nonsway 410.13.1 Compression members shaH be designed for the factored axial load, Pu , and the moment amplified for the effects of member curvature, Mn as follows: (410·12)
M 2.min = PI. (15 + O.03h)
(410-18)
about each axis separately, where 15 and h are in millimeters. For members for which M 2.min exceeds M 2 , the value of Cm in Equation (410·17) shall either be taken equal to 1.0, or shall be based on the ratio of the computed end moments, M, 1M2. 410.141\:\0ment Magnification Procedure· Sway 410.14.1 The moments MJ and M, at the ends of an
individual compression member shall be taken as:
where: ~
1.0
(410·13)
where I~.
7[2
EI
(410·14)
(kl" )'
(410·19)
Mz"s +
(410·20)
0: MI.! and Os M zs shall be computed according to
Sections 410.14. J.3 or 410.14. 1.4.
410.14.1.1 Flexural members shall be designed for the total magnified end moments of the compression members at the joint.
410.13.1.1 El shall be taken as:
E I =fE:2EJ, +EJ,,)
M ln.1 +
(410·15)
1+ PdllJ
410.14.1.2 The effective length factor k shall be determined
using the values of Be and I givcn in Section 410.12.2 and shall not be less than 1.0.
or
EI
410.14.1.3 The moment magnificr (5s shall be calculated as
(O.4E,1 , )
(410·16)
1+ Pdll.1
(410·21)
Alternatively, EI shall be permitted to be computed using the value of 1 from Eq. 410·9 divided by (I + (I"",).
If 8.\ calculated by Eq. 410-21 exceeds 1.5, S.! shall be calculated using second-order elastic analysis or Section
410.13.1.2 The term f!,/".< shall be taken as the ratio of maximum factored axial sustained load to maximum factored axial load associated with the same load combination, but shall not be taken greater than 1.0.
410.14.1.4.
National Structural Code of the PhilipPines Gill hlition Volume 1
4·54
CHAPTE" 4 . Concrete
410.14.1.4 Alternatively. it shall be permitted to calculate os as;
.
I
< ~----->I 0,
(410·22)
IP"-
1--··_···
0.75IP, where 'fPII is the summation for all the factored vertical loads in a story and "LPc is the summation for all swayresisting columns in ':1 story. Pc is calculated using Eq. 41014 with k determined from Section 410.14.1.2 and EI from Section 410.13.1.1, where lid, shall be substituted fol' lidm.
410.15 Axially Loaded Members Supporting Slab System Axially loadcd members supporting slab system included within the scope of Section 413.2 shall be designed as provided in Section 410 and in accordance with the additional requirements of Section 413. 410.16 Transmission of Column Loads through 'Floor System
410.17.2 Strength of a composite member shall be computed for the same limiting conditions applicable to ordinary reinforced concrete members. 410.17.3 Any axial load strength assigned to concrete of a composite member shall be transferred to the concrete by members or brackets in direct bearing on the composite member concrete.
or
410.17.4 All axial load strength not assigned to concrete a composite member shall be developed by direct connection to the structural steel shape, pipe or tube.
410.17.5 For evaluation of slenderness effects, radius of gyration, r, of a composite section shall not be greater than the value given by:
O.2EJg +E~~ 0.2E,A, + E,A"
(410·23)
and, as an alternative to a more accurate calculation, EI in Eq. 410·14 shall be taken either as Eq. 410·15; 01'
EI ~(~)E I EI
When the specified compressive strength of concrete in a column is greater than 1.4 times that specified for a floor system, transmission of load through the floor system shall be provided by Sections 410.16.1, 410.16.2, or 410.16.3:
1+ fJdlU
~ K
+
J
(410·24)
Ix
410.17.6 Structural Steel Encased Concrete Core 410.16.1 Concrete of strength specified for the column shall be placed in the floor at the column location. Top surface of the column concrete shall extend 600 mm into the slab from face of column. Column concrete shall be well integrated with floor concrete, and shall be placed in accordance with Sections 406.4.6 and 406.4.7.
410.17.6.1 For a composite member with concrete corc encased by stI1lctural steel, thickness of the steel encasement shall not be less than:
410,16.2 Strength of a column through a flnor system shall be based on the lower value of concrete strength with vertical dowels and spirals as required.
nor
410.16.3 For columns laterally supported on foUl' sides by beams of approximately equal depth or by slabs, it shall be permiued to base strength of the column on an assumed concrete strength in the column joint equal to 75 percent of column concrete strength plus 35 percent of floor concrete strength. In the application of this Section, the ratio of column concrete strength to slab concrete strength shall not be taken greater than 2.5 for design.
for each face of width b
-t;
h -8E .'
J
for circular sections of diameter h
410.17.6.2 Longitudinal bars located within the encased concrete core shall be permitted to be used in computing An and /.u" 410.17.7 Spiral Reinforcement Around Strudllrai Steel
Core 410.17 Composite Compression Members 410.17.1 Composite compression members shall include all such members reinforced longitudinally with structural steel shapes, pipe or tubing with or without longitudinal bars.
A composite member with spirally reinforced conereii' around a stmctural steel core shall conform to Sections 410.17.7.1 through 410.17.7.4.
410.17.7.1 Design yield strength of structural steel corc shall be the specified minimum yield strength for gr;Hic structural steel used but not to exceed 350 MPa.
Association-of Structural Engineers of the Philippines
CHAPTER 4 . Concrete
410.17.7.2 Spiral reinforcemen l shall conform to Section
410,10,3,
410.18.2 Section 4 10, 18 does not apply to post-tensioning anchorages,
410.17,7,3 Longi tudi nal bars located within the spiral shall f1 0 t be less than 0.01 or morc than 0.08 times net area of concrete sectio n. 410.17.7.4 Longitudinal bars located within the spiral shall be permitted to be used in computing As'\" and I,x. 410.17.8 Tie Reinforcement Around Structural Steel
Core A composite member with laterall y lied concrete around a slructural steel core shall conform to Secti o ns 41 0.17,S. 1 through 4 10,17,8,7: 410.17.8.1 Des ign yield strengtll of structural steel core shall be the specified minimu m yield strength for grade of structural steel used bu t not to exceed 350 MPa. 410.17.8.2 La teral ties shal l eX lend co mpletel y around the stru ctural steel core. 410.17.8,3 [-'1teral ti es shall have a di ameter not less than 0.02 times the greatest side dimen sion o f composite member, except that ti es shall not be small er than 10 mm diameter and are not required to be larger th an 16 mill diameter. Welded wire fabric of equi va lent area shall be permitted. 410.17.8.4 Vert ica l spac ing of lateral lies shall not exceed 16 longitud in al bar diamcters, 48 tie bar diamcters , or one half times the leas t side dimension of the composite member. 410.17.8.5 Longit udi nal bars located within the tics sha ll nOI be less than 0.0 1 or more th an 0.08 limes net area o f concrete seclion. 410.17.8.6 A longitudinal bar shall be located at every comer of a rectangular cross section, with other longitudinal bars spaced not farther apart than one half the least side dimension of the c O l11 po~ ite member. 410.17.8 .7 Longitud inal bars located with in the ties shall be permitted to be used in compu ting A.u ,l nd 1.0 :, 410.18 B earing S trength 410.18.1 Design bearing stre ngth on concrete shall not exceed ¢(0,8S[, A,), except when the supporting su rrace is wi der o n all si des th an the loaded area , the n the des ign bearing streng th on (he loaded area shall be penn ili ed 10 be mu ltiplied by A21 A" bu t by nOI more (h'ln 2.
National Structura l Code of the PhilippifwS 6
l
4·55
111
Edition Volum e 1
4-56
CHAPTER 4 - Concrete
c] 411.1 Notalions A ~.
'=
arc
A fP AJ
A,t
All AI
= area enclosed by outside perimeter of concrete cross section, mm 2. Sec Section 411.7.1 ::= area of reinforcement in bracket or corbel resisting factored moment [Vua + Nuc(IJ· d)). mm 2 = gross area of section, 111m2. For a hollow section, A, is the urea of the concrete on ly and does not inctude the arca of the void(s) = area of shear reinforce ment parallel to primary tension reinforcement in erbel or bracket, 111m2 = lotal area of longitudinal reinforce ment to resist
d
dl'
fr
.JT: ;: :;
let
Jd
torsion, mm 2
A ,.mill An
An A"h AJ Ale
At
A\' A ,!
A ,.11 A". mill
minimum area of longitudinal reinforcement to resist torsion. mm 2, Sec Section 411 .7.5.3 :::: area of reinforcement in bracket or corbel res isting tensile force NII(, nun 2 • See Section 411 .10 ::: gross area enclosed by shear flow path. mm 2 :;: area enclosed by centerline of the outermost closed transverse torsional reinforcement, 111m2 ;:; area of non prestressed longitudinal tension reinforcement . mOl 2 ;:; area of primary tension reinforcement in a corbel or bracket, ffim2. Sec Section 411.10.3.5 := area of one leg of a closed stirrup reSisting IOrsion within a distance s. mm 2 ;:; area of shear reinforcement within a distance s, mm 2 ::; area of shear·friction reinforcement, mm 2 ;: ;lrea of shear reinforcement parallel to nexural tension reinrorccmenl within a spacing Sz, mlll 2 = minimum arca of shear reinforcement within it Spacing s, 111m 2. Sec Sections 411.6.6.3 ,md ::::
/p<
h'~
It!! J"u 1;.
h·t
411.6.6.4
a b b" ht
hot" /)1
/;2
CI
:::: shea r span, distance between concentrated load and
face of supports. mm :;: width of compression face of member, mm :::: perimeter of cri tical section for shear in slabs and footings, nUll . See Section 411.13. J.2 ::: width of thilt part of cross section containing the closed stirnJps resisting torsion, mm ::: web width, or diameter of circular section, I1Ull :;; dirnc.nsion of the critical section /)0 defined in Section 411 ,13. 1.2 measured in the direction or the span for which moments are determined, mill == dimension of Ihe critical :-;ecti oll /}o defined in Section 411 . 11.1.2 Illc<1surcd in the direction perpendicular to b,. mOl ::: dimension of re-clangular or equivalent rectangular column , capital or bracket measured in the
direction of the spa n for which l11omel1lS .Irc being determin ed, mm ;:::; dimension of rectangular Of equivalent rectangular column, capital or bracket measured tran sverse to the direction of the span for which moments arc being detennined. 111m ;:::; distance from extreme compression fiber to centroid of longitudinal tension reinforcemellt, mm ;:::; distan ce from ext reme co mpression fiber to centroid of prestressing steel, mm ;:::; specified compressive strength of concrete, MPa square root of specified compressive strength of
II h,. h",
/" I,. /".
M.·re'
M",
concrete. MPa = average spli tting tensile strength of lighlweigi,t aggregate concrete, MPa = stress due to unfactored dead load, at extreme fibc! of section where tensile st ress is caused by externally applied loads, MP. = compressive stress in concrete (after allowance for all prestress losses) at cen troid of cross sectio n resisting externally applied loads or at junction of web and nangc when (he cel1lroid lies within the flan ge, MPa. (In a composite member, he is resultant compressive stress at centroid ur composite section, or at junction of web and flang(.;. when the cCl1Iroid lies within the flange. due ( 0 both prestress and moments resisted by prccw;{ member acting alone). = compressive stress in concrete due to effective prestress forces on ly (after allowance for all prestress losses) at ex treme fiber of sec ti on where tensile stress is caused by externally applied loads, MPa ::: st ress in prestressi ng steel at nOminjll nexural strength, MPa ::: specified (ensile strength of prestrl;.ssing steel, MPa = speci fied yield strenglh of reinforce ment, MPa ::; specified yield st rength J... of transverse reinforcement, MPa = overall thickness or height of member, nUll ::: lotal depth of shearhead cross section, mm = height of entire wall from base to top or height of lile segment of wa ll considered, mill = moment of inertia of seclion of heam about til e celllroidal axis, mm 4 ;:::; length of clear span measured face to face of supports, mill = lenglh of shearhcad ;!I'1ll from cCJlIroid of concentrated load or reaction, m11l :;; length of entire wall or lenglh of segment of wall considered in direction of shear force, mill = momenl causing flexural cracking at sectioll duc (0 externally applied loads, N-IllIl1. See Sc\tiou
4" .5.3 .1 moment modified 10 accolin{ for cI'J'v ' ot . axial compression, N·mnl. See Section '111.4 .1..2
= factored
Association o f Structural Engineefs of tile P!ljJjppines
CHAPTER 4 . Concrete
Mmi!x
= maximum factored moment at section due to
externally applied loads, N~mm Mil :::: nominal flexural strength at section, N-mm Mp = required plastic moment strength of shearhead cross section, N-mm Mu = factored moment at section, N-mm M\. = moment resistance contributed by shearhead reinforcement, N-mm 11 number of items, such as strength tests, bars, wires, monostrand anchorage devices, anchors or shearhead arms Nil = factored axial load normal to cross section occurring simultaneously with VII or TIl; to be taken as positive for compression, negative for tension, N NIl(' factored horizontal tensile force applied at top of ~)racket or corbel acting simultaneously with V" to be taken as positive for tension, N Pcp outside perimeter of the concrete cross section, nun /h perimeter of centerline of oulennost closed transverse torsional reinforcement, nun s =- center-to-center spacing of items, such as longitudinal reinforcement, transverse reinforcement, prestressing tendons, wires, or anchors, mm S2 = center-to-center spacing of longitudinal shear or torsion reinforcement, mm 7~ = nominal torsional moment strength, N-mm 1~ = factored torsional moment at section, N-mm I ~ thickness of a wall of a hollow section, mm V, nominal shear strength provided by concrete, N Vci ;;;: nominal shear strength provided by concrete when diagonal cracking results from combined shear and moment, N V(!I' := nominal shear strength provided by concrete when diagonal cracking results from high principal tensile stress in web, N Vd = shear force at section due to unfactorcd dead load, N VI =: factored shear force at section due to externally applied loads occurring simultaneously with M"'(H.
=
fJ
y..
=
= =
=
N Vn
= nominal shear strength, N
Vp
= vertical
Vs VI. V'I
)'/
a
«, ~,
component of effective prestress force at section, N ;;;: nominal shear strength provided by shear reinforcement, N = factored shear force at section, N ::;:: nominal shear stress, MPa. Sec Section 411.13.6.2 ::::: distance from centroida! axis of gross section, neglecting reinforcement, to tension face, mm =: angle defining the orientation of reinforcement =: constant used to compute Vc in slabs and footings = ratio of flexural stiffness of shearhead arm to surrounding composite slab scction. Sec Section 411.13.4.5
p
4·57
::::: ratio of long to short dimension; sides of column, concentrated load 01' reaction area, or sides of footing, see Section 411 ::::: factor used to compute Vc in prestressed slabs. = factor used to determine the unbalanced moment transferred by flexure at slab-column connection. Sec Section 41 I = factor used to determine the unbalanced moment transferred by eccentricity of shear at slab-column connections. See Section 411.13.7.1
= I - Yr ;: ;: number of identical arms of shearhead = coefficient of friction. See Section 411.8.4.3 = modification factor reflecting the reduced mechanical properties of lightweight concrete, all relative to normal weight concrete of the same compressive strength. See Section 411.8.4.3. =- ratio of nonprestressed tension reinforcement. = Ajbd
= ratio
p,
of area of reinforcement to gross to that reinforcement = ratio of area of reinforcement to gross to that reinforcement ~
distributed longitudinal concrete area perpendicular distributed transverse concrete area perpendicular
Ajb"d
PI\' B
= angle of compression diagonals in truss analogy for
¢
= strength reduction factor.
torsion See Section 409.4
411,2 Shear Strength 411.2.1 Except for members designed in accordance with Section 427, design of cross sections subject to shear shall be based on (41 I-I) where VII is factored shear force at section considered and V,\ is nominal shear strength computed by (411-2) where Vc is nominal shear strength provided by concrete in accordance with Seclion 411.4 or Section 4 J 1.5, and VI is nominal shear strength provided by shear reinforcement in accordance with Section 411.6.6.
411.2.1.1 In determining shear strength V,,, the effect of any openings in members shall be considered. 411.2.1.2 In determining shear strength V,., whenever applicable, effects of axial tension due to creep and shrinkage in restrained members shaH be considered and effects of inclined flexural compression ill variable-depth members shall be permitted to be included. th
National Structural Code of the Philippines 6 Edition Volume 1
4·58
CHA PTER 4· Concrete
J. ~ f" 1(0.56
411.2.2 The values Of..Jf': used in SCClion41i1 shall not exceed 8.0 Mra. except as allowed in Section 411.2 .2. 1.
JF:.) ,; 1.0.
N.B. Sect. 411 .3 nol in AC I. ad apted from NSCr 5~ Ed.
411.2.2. 1 Values o f ..Jf': greater th an 8.0 MP" are 411.4 Sh ea r Slrength Provided by Concre le for
all owed in compu ting Vo V ... and Vel<' fo r rcinl orced or prestressed concrete beams and concrete joist cons tru ction having mi ni mum web reinforce ment in acco rdance with Sect :OIts 411.6.6.3 .411 .6.6 .4 and 411 .7.5.2.
411.4.1 S implified Calculation for Yc
411 .2.3 Co mputations of maximum [aclOrcd shea.r force Vu al su ppons in accordance wilh Section 411 .2.3. 1 or 4 11.2.3.2 shall be permitted if all o f Ihe fo ll o wing three condit io ns are sali s ficd :
Shear strength Vc s hall be co mputed by pro ViS. \lf.S {1[ Sections 411.4.1 . J thro ugh 411.4 . 1.3 unless a more detai I(·..j calcul ation is made in accord ance with Secti on 41J .4.2. Throu ghout thi s Section, except in Secti on 411.8, A, shall b~ as defined in Section 408.7. 1.
J. Support reaction, in di rection of introdu ces compress ion member;
into
Nonp rcstressed Members
applie~d
the end
shear. regions of '
411.4.1.1 For members subjecllO shear and nexure only: (411 -3)
2.
Loads Urc applied at or near the top o f the membe r; and
3.
No concentrated load occurs between face of support
411.4.1.2 For members subj ect to ax ial co mpression,
V~
411. 2. 3.1 and 4 11.2.3.2. 4J 1.2.3.1 For Ilonprestressed members, sections locawd less th an a distance d from facc of SUPI)Qlt shall be pennilteci to be de signed for thc same shear V" as Ihat computed at a di stance d.
411.2,3,2 For prestressed members, secti ons locat ed less than .1 distance hl2 from face of support shall be permitted to be designed for Ihe same shenr V" as thaI co mputed at a distance " 12. 411.2.4 Fo r deep bC Il IllS, brackets an d corbels. wa ll s and slabs and foolin gs, the specia l prov isions of Secti ons 4 11 .9 Ih rough 4 11. 13 sholl opply. 411.3 Lightweight Concrete
t
0.17
(I'" ~')2ff b . d (411-4) 14A ,."
t
Quan tity Nu/Ag shall be expressed in MPa. 411.4.1.3 For members subject (0 si gnificant axial tension, Vc shall be taken as zero, unless a more detailed analysis is made using Section 411.4 .2.3. 411.4.2 Delailed Ca lcu la li on for V, Shear strength V.. shall be pcnnillcd 10 be computed by the more dClailed calcul.at io n of Sectio ns 4 11.4 .2.1 throu gh
4 11.4 .2.3. 411.4.2.1 For members subject to shear and n cx.ure onl y, (4 11·5)
v,
4J 1.3.1 Prov isio ns for shcar stre ngth Vc apply to norma lweigh t co ncretc. When lightweight aggregate conc rete is used, one o f the fo ll ow ing modifi cat ions shall appl y:
but not great er {hall 0.29..Jf': b... d. Whe n computinr.
\~
hy Eq . 411-5. Vu d / M u shall not be taken grea tcr th;m ::.
411.3.1.1 When J,., is not spec ifi ed . all values o f ~
affecting \I, . ., ~ amI. Mn s hall be lllultiplied by a mod ilicat io ll fac tor A. where}. is 0.75 for all -li g htweigh t conc rete and 0.85 for sand-li ght weight concrete. Linear illlcrpol:ltion between 0.85 and 1.0 shall be permit ted, Oil thc basis of vo lumetric fractions, for concrete containing normal weight fine agg regate and a blend of li ghtweight and normal wei ght coarse aggregates. For normal wei ght co nc rete , ), = 1.0. If av erage splitting tensile strength of li ghtweight con crete.Pn. is specified,
where Mil occurs simultaneollsly with considered.
V.. ;\1
SCl'I :!,,;
411.4.2.2 For me mbers subj ect to axial compression, il shall be pe rmitted to compute Vt. using Eq, 4 11-5 wilh M,.; substituted for Mu and VI,d/MI, not then limitcd to ! .0. where:
M", -- M "Nil
Association of Stru ctural Engineers of the Pililippines
(4" 8-11 ) ---
CHAPTER 4 . COllcrete
However, Vc shall not be taken greater than:
4·59
411.5.3.1 Shear strength V,; shall be computed by (411-7)
.j-j-:- b = A. --'
V.
20'"
co
_=
V M
+ V + _,_ .
d I'
"
(411-10)
M rn"~
where dp need not be taken less than 0.80h and NjAg shall be expressed in MPa. When Milt as computed by Equation (411-6) is negative, Vc shall be computed by Equation (411-7). 411.4.2.3 For members subject to significant axial tension,
(411-8)
but not less than zero, where Nu is negative for tension. N"IAg shall be expressed in MPa. 411.4.3 Circular Members
f·)i
M cr<'-~' _10 SA Y.lc r;:;-(, + .(p c- . d
(411-11 )
y,
and values of M"wx and Vi shall be compmed from the load combination causing maximum factored moment to occur at the section. Vci need not be taken .less than 0.1 no. 411.5.3.2 Shear strength
ff bl.ji.
v..". shall be computed by (411-12)
where dp need not be taken less than 0.80h.
For circular members, the area used to compute Vc shall be taken as the product of the diameter and effective depth of the concrete section. It shall be permitted to take the effective depth as 0.8 times the diameter of the concrete section.
Alternatively, Vc ". may be computed as the shear force corresponding to dead load plus live load that results in a
411.5 Shear Strength Provided by Concrete For
of member, or at intersection of flange and web when centroidal axis is in the flange. In composite · members, principal tensile stress shall be computed using the cross section that resists live load.
Prestressed Members 411.5.1 For the provisions of Section 411.5, d shall be taken as the distance from extreme compression fiber to centroid of prestressed and nonprcstressed longitudinal tension reinforcement, if any, but need not be taken less than 0.80h. 411.5.2 For members with effective prestress force not less than 40 percent of the tensile strength of flexural
reinforcement, unless more detailed calculation is made in accordance with Section 411.5.3.
v,
[A.1f:
+ 4.8
~ ~ Jb
but Vc need not be taken less than 0.17),
w
d
ff by.Li
Vc be taken greatcr than 0.42), jf~ bud
(411-9)
nor shall
nor the value
given in Sections 4 I J .5.4 or 411.5.5. VlldlM" shal! not be takcn greater than ! .0, where M" occurs simultaneously with V" at section considered. 411.5.3 Vc shall be pennittcd to be computed in accordance with Sections 411.5.3.1 and 41 1.5.3.2 where Vc shall be the lesser of Vci or V'.l>".
principal tensile stress of 0.33}
ff at the centroidai axis
411.5.4 In a pretensioned member in which the section at a distance 1112 from face of support is closer to end of member than the transfer length of the prestressing steel, the reduced prestress shall be considered when computing V,." .. This value of \~'l<" shall also be taken as the maximum limit for Eq. 411-9. The prestress force due to tendons for which bonding does not extend to the end of the member shall be assumed to vary linearly frorn zero at point at which bonding commences to a maximum at a distance from this point equal to the transfer length, assumed to be 50 diameters for strand and 100 diameters for single wire.
In a pretensioned member where bonding of some tendons does not extend to end of member, a reduced prestress shall be considered when computing Vc in accordance with Section 411.5.2 or 411.5.3. The value of Vcwca!culated using the reduced pr{'stress shall also be taken as thc maximum limit for Equatioi( (411-9). Prestress force due to tendons for which bonding docs not cxtend to end of mcmber may be assumcd to vary linearly from zero at the point at which bonding commences to a maximum at a distance from this point equal to the transfer length, assumed to be 50 diamcters for strand and 100 diameters for single wire. 411.5.5
th
National Structural Code of the Ptlilippines 6 Edition Volume 1
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CHAPTER 4 . Concrete
411.6 Shear Strength Provided b)' Shear Reinforcement
411.6.5.3
Where Vs exceeds 0.33
ff,. h ... d.
1 11. 6. ~. 2
411.6.1 Types of Shear Reinforcement
spacing given in Sections 411.6.5.1 and reduced by one half.
411.6.1.1 Shear rcinforccn1cnI consisting of the following shall be pCfmi(lcd:
411.6.6 Minimum Shcar Reinforccme nt
I.
Slinl1ps perpendicular to axis of member;
2.
Welded wire fabric with wires loc
3.
Spirals, circu lar ties, or hoops.
411.6.1.2 For lIonprcslfcssed members. shear reinforcement shall be penrullcd to also consist 0[: I. 2.
3.
SlinlJps making an angle of 45 degrees or morc with iongilUdinallcnsion reinforcement;
maximum shall b:;
411.6.6.1 A minimum area of shear fl'i nforcc ment, A".min, shall be provided in all reinforced COw'n .":. flexural members (prestressed and nonpres(resscJ ) Wht:T:. / // eXCe{~i~", O.5¢V(". except in members satisfying one or ;..orc of (i ) through (6): Solid slabs and footings;
1.
HoIlow~core
units with tOlal unlopped depth Ilot
greater than 300 mm and
h ollow ~c o rc
un its where
Longitudinal reinforcemclH Wil h belli porti on Jll
2.
Vu is not greater than O.S¢ V("".;
nn angl e of 30 degrees or more wi th the longitudi nal tension reinforcement;
3.
Concrete joist construction defined by Section 408.14 ;
4.
Bcams with (owl depth, Ii not greate r thnn 250 mm~
5.
Beams integral with slabs with total depth, " not greater than 600 mm, and not greater than 2 .~) limes thickness of flange or 0.50 th e width of web;
6.
Beams constructed of steel ti bc r.. r e i nro ~ ·c ed, 110nn;;I weight concrete with It' not exceedil1 g 4~J MPa, h Ho i greater than 600 mill, and Vu not grealer (han ¢O. J 7
Combinati on
of
stilTUPS
and
bent
longitudinal
reinforcement. 411.6.2 Tile values of 1;. and 1,./ llsed in the design of shear rein fo rce ment shall not exceed 41 5 MPa, except the value shall not exceed 550 MPa for a we lded defo rm ed wire rei nforcemenl. 411.6.3 Where the provisions of Section 411.6 are applied to prestresscd mcmbers. d shall be laken as the di stance from extreme comp ression fiber to centroid of the pres tressed and non prestressed longitudinni tension rei nforcement, if an y. bUlllecd not be taken less than 0.80h.
411.6.4 Stirrups and other bars or wires used as shear reinforcement shall extend to a distance d frolll extre me compression fiber
ffb.d 411.6.6.2 Minimum shear reinforcement rcquir:·mcnts of Section 411.6.6.1 shall be waived if sh uwn by test that required nominal nexural, Mn and shear :-.' rcngth , "" can be developed when shear reinforcement is ( ·,It(ed . .,l;·h I.esl shall simulate effects of differential '!! icm,' ,. creej:, shri nkage and temperature change, be,!}"': 0 11 : H ;disli: assessmelll of such effects occurring in sen ice. 411.6.6.3 Where shear reinforcemenl' is reqlli re(\ ,,)' :-'ectioJ ' 4 11 .6.6. 1 or for strength and where Secril,;} 4; I.; i ·. ;J ow ~ torsion to be neglected, the min imulll :~ ..~:! o ~ :.he.l'· reinforcement for prestressed (except as . ) j )\lidj'~ ; !i ' " " li' J; 4 I 1.6.6.4) and nonpre5tressed member', :-.1: d ;1:. '.\ . ',11', by:
b .f A . = 0.062 Vrr;-j' ~ J r; j
(4 11·1 3)
r . 1IlI11.
y'
411.6.5.2 Inclined slim.lps and belli longitudinal reinforcement shall be so spaced {hat every 45·c!egrcc linc, extending tow.mJ the reaction frOI11 mid ~d c pth of member d/2 10 longilUdi nal tension reinforcement. shall be crossed by al le.lsl one line of shear reinforcement.
but shall not be less than (0.35b ...'i)IJ;." in millimeters.
Association of Stru ctura l Enginee rs of the Philip pines
WIL i~: i) .. .',,:.
CHAPTER 4 - Concrete
411.6.6.4 For prestressed members with effective prestress force not Jess than 40 percent of the tensile strength of flexural reinforcement, A"min shall not be less than the ,mailer value from Equatio;\s (411-13) and (411-14).
Av, min
-
AI"!'" s 80! d y
Jfl
(411-14)
b
4·61
411.6.7.6 Where shear reinforcement consists of a series of parallel bent-up bars or groups of parallel bent-up bars at different distances from the support, shear strength Vs shall be computed by Eq. 411-16.
411.6.7.7 Only the center Ulfee fourths of the inclined portion of any longitudinal bent bar shall be considered effective for shear reinforcement
".
411.6.7 Design of Shear Reinforcement 411.6.7.1 Where factored shear force VII exceeds shear strength ¢Vn shear reinforcement shall be provided to satisfy Equations (411-1) and (411-2), where shear strengU\ V~ shall be computed in accordance with Sections 411.6.7.2 through 411.6.7.9.
411.6.7.8 Where more than one type of shear reinforcement is used to reinforce the same portion of a member, shear strength, Vs shall be computed as the sum of the Vf values computed for the various types of shear reinforcement.
411,6,7,9 Shear strength V, shall not be taken greater Ulan 0.66.JT: bwd.
411.6.7.2 Where shear reinforcement perpendicular to axis of member is used,
V =
,
411.7 Design for Torsion
A.../Yld
(411-15)
s
where A" is the area of shear reinforcement within spacing s. 411.6.7.3 Where circular ties, hoops, or spirals are used as shear reinforcement, V, shall be computed using equation (411-15) where d is defined in Section 411.4.3 for circular
Design for torsion shall be in accordance with Sections 411.7.1 through 411.7.6, or 411.7.7. 411.7,1 Threshold Torsion
It shall be pennitted to neglect torsion effects if the factored torsional moment Tu is less than:
1.
For nonprestressed members:
members, Ay shall be taken as two times the area of the bar (411-18)
in a circular tie, hoop, or spiral at a spacing s, s is measured in a direction parallcl to longitudinal reinforcement, and 1)'1
is the specified yield strength of circular tie, hoop or spiral reinforcernent. 411.6.7.4 Where inclined stirrups
are Llsed
as
2.
For prestressed members:
shear
(411-19)
reinforcement,
. ) Vo =A.,.J"d - - - (sma+cosa s
(411-16)
3.
For nonpreslressed members subjected to an axial tensile or compressi ve force:
where a is angle between inclined stirrups and longitudinal axis of the member, and s is measured in direction parallcl to longitudinal reinforcement.
411.6.7.5 Where shear reinforcement consists of a single bar or a single group of parallel bars, all bent up at the same distance from the suppOI1, V,~A...rysil\a
(411-17)
but not greater than 0.25 J7~~- b"d, where
0:
is
angle
between bcnHlp reinforcement and longitudinal axis of the member.
(411-20)
For members cast monolithically with a slab, the overhanging flange width used in computing AfJl and Pcp shall conform to Section 413.3.4. For a hollow section, Ag shall be used in place of Acp in Section 411.7.1, and the outer boundaries of the section shall conform to Section 413.3.4. 411.7.1.1 For isolated members with flanges and for members cast monolithically with a slab, the overhanging flange width used to compute Aq) and Pcp shall conform to Section 413.3.4, except that the overhanging flanges shall be neglected in cases where the parameter A2cp fpcp calculated
National Structural Code of t~e Philippines 6
th
Edition Volume 1
4·62
CHAPTER 4 . Conerele
for a beam with flanges is less th an thal computed for the sa me beam ignoring the flanges.
a concentrated torque OCClI rs within this di stance, the critical section for design shall be at the face of the SUppOIl.
411.7.2 Ca lculation of Factored Torsional Moment
411.7,3 Torsional Moment Strength
411.7.2.1 Hlhe factored torsional moment,
r u , in
a member
is required to maintain equilihrium and exceeds the minimum val ue given in Section 411.7. 1, the member shall be designed to carry Tu in accordance wit h Sections 411.7.3 through 41 1.7.6. 411.7.2.2 In a staticall y indeterminate structure where reductio n of the torsional moment in a member can occur due to redi stri bution of internal forces upon cracking. the max imum factored torsional moment, Tu shall be permilled lO be reduced to the values given in (I). (2). or (3). as applicable:
I.
For nonprcslrcsscd members, at the sections desc ri bed in Secti on 41 1.7 .2 .4:
¢4 .fj-:: 3
-~--- --- -
2,
( ._A,~ )
(4 11 ·2 1)
PCI'
For prestressed members, at the sections described ill Seelion 411.7.2.5:
(411 ·22)
3.
411.7.3.) The cross-secti onal dimensions shall be such lhat: I.
For sol id secti ons:
(4 11 ·24) 2.
For hollow sections:
+( 1.7l~p, )<¢(~+ 2JT:) (...'b •.:.....) d A... ' b •.tI 3
(411·25)
For prestressed members. d shall be detcnnincd . in accordance with Section 41 1.6.3.
411.7.3.2 If the wall thicknes s vades around the perimeter of a hollow section. Eq. 411·25 shall be evaluated al the location where the left· hand side of Eq. 411·25 is a
maximum. 411.7,3.3 If the wall thi ckness is less Ihan A",/p,.. Ihe seco nd term in Eq. 411·25 shall be taken as:
For non prestressed members subjected to an ax ial tensile or compress ive force:
ry(A':)R. P:; A.,lfT:
¢,l vi, 3
,
I
(4 11 ·23)
+ 0.33
In (I). (2). or (3). the correspondi ngly redislributed be nding moments and shears in the adj oining members shaH be used in [h e design of these members. For hollow sections. ACfl shall not be replaced with A, in Secti on 411 .7.2.2.
where I is the thickness of the wall of the hollow section at the locat ion where tile stresses arc being chec ked. 411.7.3.4
The values of
1,.
and
1,.,
used for design of
lOrsional reinforcement shall not exceed 4 15 MPa. 411.7.3.5 Where T. exceeds Ihe Ihreshold torsion. des ign of the cross section shall be based on:
411.7.2.3 Unless dctennincd by a more exact ana lysis, it shall be penn iHcd 10 take the torsional loading from a s lab as un iform ly distributed along the member.
¢T"
?
1~
(411·26)
411.7.3,6 Tn shall be compu ted by: 411.7.2.4 In non prestressed members. secli o"ns located Jess th an a d istance d from the face o f a suppo rt shall be des igned for not less than the IOrsioll Til comptiled <:11 :l di stance d. If a concent rated torque occ urs within this di stan ce, tbe critical sect ion for design shall be at the face of th e SUppOit.
411.7.2.5 In prestressed members , sections located less than a distance hl2 from the face of a support shall be designed for not less than the torsion 'f;, computed at a distance h12. If
T, = 2A.A,f" cotO
(411·27)
s
where A" shaH bc determined by analysis except that it dJa!i he permitted to take Af) equal to O.85Alllr: e shall II:':.. taken smaller than 30 degrees nor larger than 60 degrees. ii shall be permitted to take
I.
e equal to:
45 degrees for nonprcstrcssed members or mcm/)el':'; with less prestress than in Itclll 2 below,
Association of Structural Engineers of the Philippine s
CHAPTER 4 - Concrete
2.
37.5 degrees for preslre.o;;sed mcmbers wilh an effective prestrcss force not less than 40 percent of the tensile strength of the longitudinal reinforcement.
411. 7.3. 7
Tile additional longitudinal r(;quired for IOrsion shall not be less than :
A, f,., '0 A, = P .,,_._'- cot· " s j'
re inforcement
(411-28)
4-63
2.
A closed cage of welded wire fabric with transverse wires perpendicular to the axis of the member; or
3.
In l10 nprestressed beams, spiral reinforcement.
411.7.4.2 Transverse torsional reinfo rcement anchored by one of the foll o wing:
shall
be
1.
A 135-degree standard hook, or seisrnjc hook as defined in Sec lion 402, around a longilUdinal b,u';
2.
According to Sections 412.14.2.1, 412.14.2.2 Of 412. 14.2.3 in regions where the concrete SUITounding lhe anchorage is restrained against spalling by a flange or slab or similar me mbe r.
."
where 0 shi.lll be Ihe sa me value used in Eq. 411-27 and A, 1\' shall be Hlken as the a mount compuled from Eq. 4 f 1-27 nol m odified in accordance with Section 411 .7 .5.2 or 4 11.7.5.3 ; J,., refers to closed transve rse torsional rei nforcemem, and J,. refers lO lo ngitudinal torsional reinforcement.
de velo ped
411.7.3.8 Reinforccmcm required for torsion shall be added
411.7.4.4 For hollo w sections in torsio n, the di stance
to thal required for the shear, moment and axial force thaI ac t in combinati on with the LOrsion . The most restricti ve requircl1lcnl s fo r reinforcement spacing and placement must
measured from the centerlinc of the lransverse torsional reinforcement to the in side face .of the wall of a hollow seclion shall not be less th an O.SAo/,!p"
411.7.4.3 Longitudinal 01
torsion
reinforcement shall
be
bolh ends.
be met.
411 .7.3.9 It shall be permitted to reduce the area of lo ngitudinal torsion reinforcement in the flexural com pression zone by Cl /l amounl equal to MlI/(O.9dh.)' where M" occurs at the sec ti on simultaneous with 7:" except that the reinforcement provided shaH not be less than that req uired by See li olls 411.7.5.3 of4! 1.7.6.2. 411.7.3.10 In Pres tressed Beams:
I.
2.
lOW I longitudinal reinforcemen t inc luding prestrcss ing steel iH each sectio n shall resist the factored bendi ng 1ll0 m CIl1. M" :11 that secl io n plus iJl1 additi onal concentric lo ngit udinal ten sile fo rce equal (0 Ad)'> based o n the facLOred torsion , 7~ allha t secti on; and
411.7.5 Minimum Torsion Reinforcement 411.7.5.1 A minimum area of torsional reinforcement shall be provided in all regions where the facLOred torsional moment TIJ exceeds the values specified in Sectio n 411.7.1 .
411.7.5.2 Where tors io na l re inforcement is required by Secli oll 411 .7.5.1, lhe minimulll area of tran sverse c losed s tirrups shall be computed by:
The
The spaci ng of th e long iwdinal reinforcemclll including tendons shall sat isfy the requirements in Section
411.7.6.2.
(A,. + 2A,) = 0 .062 ff, b.s but sholl not be less than (0.35b. s)It,.,.
411.7.5.3 Where torsional reinforcement is required by Section 411.7.5. I, the minimum total area of longitudinal lo rsiona l reinforcement, AI.mil! shall be computed by:
411.7.3.11 In prestre ssed beams, it shall be permitted to reduce the llrca o f longitudinal torsi o nal reinfo rcement 011 the side of th e member in compression due to nc xurc below that re qu ired by Sec tion 4 11.7.3. 10 in accordance with Seelioll 411.7.3.9.
(41 1-29)
I).,
A . = I.~u!l
5ff, A", 12/
_
,.
(~) b... s
,
/ ,. /,
(411-30)
where AJs shill! not be taken less than 0. 175b ..../h,; /,., re fers closed tfi1 nsvcr~e tors io nal reinforcement, and/, re fe rs 10 lo ng itudinal reinforcement.
(Q
411.7.4 I)ctnils of Torsional R einforceme nt 411. 7.4.1
Torsion rcinforce ment shall consist of longitudinal hars or tendons a nd Olle o r more of the foll ow ing:
1.
411.7.6 Spacing of Torsion Reinforcement 411.7.6.1 The spacing o f tran sverse torsi on re info rcement :- hall no t exceed the smaller of PhiS or 300 mill .
Closed stirrups or closed tics, perpendi cular to the axis of the member; National S tructural Code of the Pllilippines 6
1h
Edition Volume 1
4·64
CHAPTEH 4 . Concrele
411.7.6.2 The longitudinal reinforcement required for torsion s hall be di stributed around the perimeter of the closed !itinups with a maximum spacing of 300 mm, The
411.8.4.2 Where shear-fri ction reinforcement is inclined to shear plane, such thm the shear force produces tension in shear-friction reinforcement. shear strength V" shall be
longitudinal bars or tendons shall be inside the stirrups. There shall be at least one longitudinal bar or tendon in each corner of the stin-ups. Longitudinal bill'S shall have a diameter at least 1'124 of the stirrup spacing but not less than
computed by:
a 10 rnm .
shear planc.
4J 1.7.6.3 Torsion reinforccmclH shi.tlJ be provided for a distance of at least (b, + d) beyond the point required by analysis.
411 .8.4.3 The coefficient of friction JI in Eq. 411 -31 and Eq. 411·32 shall be taken as:
VII = 1I'1f,. (psin a + cosa)
where
(4 11 ·32)
a is angle between shear- fri cti on reinforcement and
Concrete placed monolithically ... ..... . 411.7.7 Alternative Design For Tors ion
For torsion design of solid sections within the scope of this Chapter wit h an aspect ratio, hlb{, of 3 or greater, it shall be pennitlcd to usc another procedure, the adequacy or whi ch has been shown by analysis and substantial agreement with results of comprehensive tests. Sections 4 1 1.7 .4 and 411.7.6 s hall apply.
Concrete placed against hardened concrete with surface intentionally roughened as specified in Sec tion 411. 8.9
411.8.1 Provisions of Section 411 .8 are to be appJied w here it is appropriate to consider shear transfer across a gi ven plane. such as an existing or potential crack, an interface between dissimilar materials. or an interface between two concretes cast a{ dirferent times. 411.8.2 Design of cross sections subject to shear transfer as described in Section 411.8.1 shall be based on Eq. 411 - 1 where V" is calculated in accordance with provisions of Sect ions 4 11.X.3 or 4 11 .8.4. 411.8.3 A crack Sh;'lll be assumed to occur along the shear plane considered . The required arca of shear-friction reinforcement A'l across lhe shear plane Illay be designed usi ng cither Section 411.8.4 or any oliler shear transfer
design methods that result in prediction or strength substantial agreement wit h results of co mprehensive lcsls.
1[1
411 .8.3.1 Provisions of Sections 41 1.8.5 throu gh 41 1.8. 10 s hall apply for all calculations of shCilr transfer strength .
411.8.4 Shea r-Fri ction Design Method
1.0,<
Concrete placed agai nst hardened concrete not intentional! y roughened .... O.6il. Concrete anchored to il!i-rolled structural steel by headed studs or by reinforci ng bars (see Section 411.8.10)
411.8 Shear· Friction
1.4'<
.......... 0.7-'
where A = 1.0 for normal-weight concrete, 0.75 for allli gh tweight concrete. Other\vise, ,{ shall be determined based on volumetric proportions of ligh twe ight and nonnalweight aggregates as specined in Sec ti on 408.7. 1. but sh,d l not exceed 0.85.
411.8.5 For nonna l-weight concrete either placed monolithically or placed against hardened co ncrele with surface intenti onall y roughened as specified in Section 411 .8.9, V" shall not excecci the small cst o f O.2f,'A" (3. 3 + 0.08;:: ) II .. and I IA ... where Ac is area of co ncrete section resislin g shear lransfer. For <111 other cases, V" shall not exceed the smaller of 0.21,.'11,. Or 5.5A,,, Where concretes of different strengths arc cast aga inst each other. the value of J..' used (0 evaluate V" shall be that or the lowcr-strcngm concrete.
411.8.6 The value of 1;. used ror de sign of shear-friction reinforcement shall not exceed 415 MPa. 411.8.7 Net tension across shear plane shall be resisted by additional reinforcement. Pcnnanenl !lei cOll1pn~ssiol1 j!cross she'lr pl,me sh.1I1 be permitted to he taken as addi tive to A ,i... the force ill the shear· friction reinforcement. when calcu lating required A,:t
411.8.4.1 Where shear-fri cli on reinforce ment IS perpendicular 10 sheilI' plane. shl~:!r strength VII shall be <.:o mpul cd by: (411 -31)
where I' is cocflici cllt o r frict ion ill accordance wi th Sectio n 411.8.4.3.
411.8.8 Shc;:II··friction reinforcement shall he appropri
develop f •. , on bOlh sides by emhcdmen!. hooks or h ) special devices .
WC';:i illg
4 J I.H.9 For the purpmic of Secti on 41 1.8. wilen concrete is placed agai!lst J1r~vjously hardened cOIH.:.re\C, thc interface
Association oj Structural Engineers of tile Philippines
CHAPTER 4 . Concrete
for shear transfer shall be clean and frcc of iai tancc, If J1 is assumed equal to J .O..?, interface sha ll be roughened to a full .lInplitudc of approximately 6 mm. 411.8.10 Whcn shear is tr~ms ferred between as-rolled steel and co ncrete using headed slUd s or welded rei nforci ng bars, steel shall be clea n and free of paint.
411.10.2 Depth at ootside edge of bearing area shall not be less than O.5d. . 411.10.3 Secti on at face o f support shall be designed to resist si mu/(aneous ly a shear Vi/o a factored moment [V"al' + N,l(' (II - tf)]. and a factored horizontal tensile force Nil,., 411.10.3.1 In all design calculations in accordance with Section 411.10, strength·reduction factor ¢ shall be taken equal to 0.75.
411.9 Deep Beams 411 .9.1 The provisions o f thi s sectio n shall appl y for members with I" Ilot exceedi ng four limes the overall member depth or regions of beams with concent rated loads withi n (wice the member depth from Ihe support Ihal are loaded on one face and supported on the opposi te face so Ihal Ihe co mpression struls can develop between the loads and the supports. Sec also Section 412.11.6. 411.9.2 Deep beams shall be designed using either nonlinear analysis as permitted in Seclion 410.8.1, or Secti on 427.
411.9.3 V" for deep beams shall not exceed 0.83
ff Ivl.
411.9.4 The area of shea r reinforcemeOl perpendicular to (il e flexural tension reinforcernen[, A,. shall not be less than 0.0025 b"slt and 52 shall not exceed dl5 and 300 mm . . 411.9.5 The area of shear reinforcemen t parallel to the nexu ral tens ion reinforcement. AI' /I shall not be less th an 0.00 15 b.. 520 and .r) shall nOI exceed dl5 and 300 mill. 411.9.6 It shall be permitted 10 provide reinforcement satisfying Section 427 .3.3 instead of the minimum hoJizontal and vertical reinforcement specified in Secti ons 411.9A and 411.9.5 . 411.I0 Provisions for Brackets and Corbels 411.10. 1 Brackets and corbels with a shear span -ta-depth ratio 0,.1 d less than 2 shall be permitted to be designed using Section 427. Design shall be permitted using Sections 411.10.3 and 411 .1OA for brackets and corbels wit h: I.
a" /d not greater Ihan I; and
2.
Subject tv factored horizontal te ns il e force. Nut:. not larger than V,..
411.10.3.2 Design of shear-frict ion reinforcement A"j to resist shear V" shall be in accorda nce with Secti on 4 11 .8. 411.10.3.2.1 Fo r nOnllal -weight concrete, shear s trength Vn shall not exceed the smallest of 0.2t,b.,d.(3.3+ 0.08!,' )b.d. and Ilb.d411.10.3.2.2 For all lightweight or sand-lightweight concrete. shear strengfh V" shall not be taken greater th an the smaller of (0.2 - 0.07a/d)j ,b.d and (5.5 - 1.9a/d) b.,d. 411.10.3.3 Reinforcemen t AI to resist moment [V"a l , + N"c (ii -d)] shall be computed in accordance with Sections 410.3 and 4 lOA. 411.10.3.4 Reinforcement All to resist factored tensile fo rce Nllc shall be determined fr~m ¢A,I,. ~ N u(' Fac(ored tensile force. N".. shall not be laken less than 0.2 V" unless provis ions arc made 10 avoid tensile forces. N"c shall be regarded as a live load even if tension resu lts from restraint of creep. shri nkage or temperature change. 411.10.3,5 Area of primary ten sion reinforcement Au' shall be made less than the larger of (AI + A.) or (2A'I/3 + A.). 411.10.4 Total area, of A,,, of closed sti rrups or lies parallel to primary tension reinforce ment shall not less than O.5(AJ'cA,,). Distribute uniformly within (2i3)d, adjacent to primary tension reinforccm en.
A,.
411.10.5 A"i bdshall not be less than 0.04 (j',i/,.). 411.10.6 At front face of brac ket or corbel, primary tension reinforcement As shall be anchored by one of the following:
J.
2. of Sections 41 1. 10.2. 411.10.3.2.1. 411.10.3.2.2. 411.10.5. 411.10.6. and 411.10.7 shall apply to design of brackets and corbels. Erfective depth d shall be de term ined at the f'lce of the SUppOIl . The
4·65
requirements
Bya structural weld to a transverse bar of at least equa l s ize; weld to be des igncd to deve lop specified yield slrcnglh/y of primary tension reinforcement;
l3y bendi ng primary tension reinforcement back to fonn
a horizontal loop; or 3.
By some other means of positive anchorage.
National Struc turC:J! Co·de of the Philippines 6
th
Edition Volurne 1
4-66
CHAP TEll 4 - Concre te
411.10.7 Bearing area on bracket or corbel shall not project beyond straight portion of primary tension reinforcement, nor project beyond interior face of transverse anchor bar (if one is provided). 411.11 Provisions for Walls 411.11.1 Design for shear fo rces perpend icu lar to facc of wa ll shall be in accordance wil h provisions for slabs in Sec ti on 411 . 13. Design for hori zont al shear forces in plane o f wall shall be in accordance wilh Secti on 411 . 11 .2 through 411 . 11.9, Alternatively, it shall be permilled to des ign walls
with a height not exceeding two rimes the length of [he wall for horizontal shear forces in accordance with Secti ons 427 and 411.11.9,2 throu gh 411.11.9.5,
whe re I,.. is the ove rall length of the wall, and Nu is posi ti ve for c{)mpression and negative for tensioll. If (MjVII - I", 12) is negative, Eq. 4 J 1·34 shall not apply. 411.11.1 Secti ons located closer to wa ll base Ihan a di stance. /,,/2 or one half thc wa ll hc ight, wh ichever is less, shall be pcrmillcd to be designed for the sCllne VI" as Ih:\I computed at a diswnce 1.. 12 or one half the height. 411.11.8 W hell (actol\;u shear force VI. is less than ¢VJ2, re inforcement shall be provided in accordance wi th Secti on 4 I 1. 11 .9 or in accordance with Sec ti on 41 4. When V" exceeds ¢ V,. 12, wall reinrorcement for resisting shear shall be provided in acco rdance with Section 411.11 .9. 411.11.9 Design of Shear Reinforcement for Walls
411.11.2 Design of hori z.ontal section for shear in plane of wa ll shall be based o n Eqs. 411- 1 and 411 -2, where shear st reng th Vco shall be in acco rda nce wit h Section 4 11 .11.5 or 4 11 . J J.6 and shear strength Vs shall be in accorda nce wi th Secti on 411. 11.9,
411.1 I .9.1 Where ractored shear rorce VII exceeds shc:.il" strength ¢ V,., hO I;zonlal shear reinforcement shall be provided to s'lIis ry Eqs. 4 11 - 1 and 4 11-2. where shea r strength V, shall be com puted by
V ~ A,J,d , s
411.11.3 Shear strength VII at an y horizollla! sectio n for shear in plane of wall shall not be taken greater than (5/6)
Jf'e lid, where II
i s thickn ess
or wall, and d is dcl1ned
in Section 41 J . 11 .4.
(411 -35)
where Al • is area of horizontal shear reinfo rce ment withi n spacing s. and distance d is determ ined in i:\ccordance with Section 4 11 . 1 1.4. Vert ical she:lr re inforce ment shall be provided in accordance wi th Section 411.11.9.4.
411 .11.4 For design ror hori zontal shear forces in pl;me of wa ll , d shall be taken eq ual to 0,8'." A larger value of d, equal to the distance fro m ext reme co mpression fiber 10 ce nter o f fo rce of a ll rein forcemelll in tension, shall be permilled to be used w hen determined by a strai n co mpatibility an alysis.
4J ] .11 .9.2 Rati o horizom:1I shear rei nforccmcnl arca to gro!'s co nc re te are:1 or vertical sccli on, Pr . slmll not be less
411.J1.5 Unless a mOre detailed calculation is made in acco rdancc with Secti on 4 J J . 11 ,6, shear strcngth VI" shall
4 J 1. t 1.9.3 SP'lc.i ll g of horiwntal sllcar reinforce ment shall ]Jot exceed the small est of /".15, 311 and 450 111m, where I", is th e overa!l length of th e waiL
not be taken greater th an ( 1/6 ) f f hd
or
Ih a" 0,0025 .
for wa lls subject
to ax ial co mpression, or V,. shall not be take n grea ter than
the va lue given in Sectio n 41 1.4 .2.3 r<'l r wa lls subject to axia l tension. 411.11.6 She,ll· st reng th VI· sh:.11 1 be permillcd to be ic!'scr or th e va lues computed rrom Eqs. 411 ·33 and 411 ·14. (411 -33)
or
411.11.9.4 Ra tio of vertical shea r rei nrorcement area 10 gross concrete area or horizontal sccl ion, P,. shall not be Ie $:-> than the larger or:
P,
~ 0 0025 + 05( 2.5 - ~,:'
}p, -
0,0025)
(411 -36)
and O . OC~;) . The vaill (! of 1'1 calculated by Eq. 411 ·36 need not be greater th an 1', required by Sec tion 411 . 11 .9. 1. In Eq. 4 11-.16. I". is Ihe overall length or the \vall. il nd II ... is the overall height of Ihe wall. 41 J. J 1.9.5 Spadllg or vertical shear reinforccmcnt sh::l ! exceed 1.../3 . 3h or 450 111m, where I ... is the oventll I cnt;.~ · •. : the wal l.
v
(411 -3 4 )
I\SSOclCl \lon
of S truC:llJf
Phil ipp ll1es
CHAPT ER 4 . Concrele
411.12 Transrer of Moments to Colullllls 411.12.1 When gravily lo.d, wind, earlhquake, or ol her lateral forces cause Iransfer of momenl al conncctions of framing clcments 10 columns, the shcar res uhing from moment transfcr shall be considered in lhe design of lateral reinforcement in th e columns. 411.12.2 Except for con nections not part of a primary seismic load-resistin g system that arc res trained 011 four sides by bea ms or slabs of appro ximately equal depth, co nnections shal! have lateral reinforcement not less than Ihal required by Eq. 4 11 - 13 within the column for a depth not less than that of Ihc deepest connection of frallling elemems to the columns. See also Section 407.10. 411.12.3 For stnlctures buill in areas of low seismicity, columns of ordinary moment framcs having a clear heightto-max imum-plal1-dimension ratio of five or less sl1
4··67
IransfCITed between a slab and a column, Section 411.13.7 shall apply. 411.13.2.1 ror nonpreSiressed sl.bs and fomings, Vc shall be Ihe s maliesl of ( I), (2), and (3): I.
v,
o
1. 6
(II 2fJ.)
A
~f' b
-.j}""
(411·37)
d
where f3 is the ratio of long side 10 short side of the column, co ncentra.tcd load Of reacti on area; 2.
V,.
~ ~ (ah,dr. 12
+
2)
A
'f'"" b v) C
(4 11 ·3&)
d 0
where «v is 40 ror interior columns, 30 ror edge columns
411.13.2.2 At colum ns of two-way prestresscd slabs and fOOlin gs that lllcet thc req uirements of Section 4 18. 10.3:
411.13 Provisions for Slabs and Footings (411 ·40) 411.13.1 The shear strength of slabs and footings in the vicinity of columns, conce ntrated loads or react ions IS gove rned by the more se vere of two condit io ns:
411.13.1.1 13C;:111l aClioll where each critical sec ti on 10 be in vcstigmed extends in a plane across lhc entire width. For bc or rooting shall he des igned in accordance with Secti ons 411 .2. 411.4, 41 1.5. and 4 11 .6. 411.13.1.2 For two-way action where each or th e critical sec ti ons to be investigated shall be located so thm its perimeter. h". is iI minimum. but need no! approach closer than dl2
wh ere jJ" is Ihe smaller of 3.5 or (a,d/b" + 1.5)11 2, a, is 40 for interior columns, 30 for edge columns and 20 for co rner columns, bo is perimeter of critical scction defined in Section 4 11. 13. 1.2. 1;". is the 'Iverage value of1;),. for the two direct ions, and VI' is the vertical component of all effective prcstrcss forces crossi ng the critical scction. V( shall be permittcd (Q be com puted by Eq . 4 J 1-40 ir the foHowing arc s.ltislied; otherwise , Section 411.13.2.1 sha ll apply: 1.
to the discontinuous edge than four timcs thc slab thick ncss:
10:
1.
Edges or corners of col ulll lls, concent rnted loads or reaction areas; and
2.
Changes in sinh thickness such as edges of cap itals,
drop panels, or shcar caps.
No portion of thc column cross section shall be closcr
2.
The va lue of F
in Eq. 4 11 -40 shall
nOI
be rakcn
grealcr th;:lll 5.8 MPa: and 3.
III each direction, /,'( shall not be less than 0.9 MPa, nor be taken greatcr than 3.5 MPa.
For two-way action. the slab of rooting shal! be designed in acco rdance with Sections 411 . 13.2 through 41 1.13 .6.
anu singlc¥lcg or multiple-leg stilTUpS shall he permitt ed in
4J 1.13.1.3 Par square or rectangul ar colu mns, concentratcd loads or reacti ons arcas, the critical scct ions with four straight s ides shall bc permittcd.
sl;!hs and rootings with d greater th an or eqnal to 150 1111ll . but not less than 16 times the shear reinforce ment bar diametcr. Shear reinforcc mcnt shaH be in accordan ce wi th Secliolls 4 I I. J3 .3. I Ihrongh 4 I I. 13.3.4.
411.13.2 TIle design or a slab or foot ing for two·way action is based on Eqs. 4 I I· I and 4 I 1·2. Vc s h. 1i be compUlcd in .ccordance wilh Secli on 4 11.1 3.2. 1, 411 . 13.2.2 or 4 11 . 13_3.1. VJ: shall be computed in accordan ce with Section 41 1_13 .3. For slabs with shear heads, VII shall bc in accordance with Section 41 1.13.4. Wh cn momcnt is
411.13.3 Shear reinrorcemcnt consisling of bars or wires
411.13 .3.1 V. shall be compnled by Eq. 411·2, where V,
shall nol be laken grealer Ihan ( 1/6) )..
F
".d, .nd V, shall
he calculatcd in accordance with Section 41 1.6 In Eq. 411 15 , A,. shall bc takcn as the cross-scctional area of all legs of
National Structurt~ l Code of the Philippilles
()!h
Edition Volum e 1
4·68
CHAPTER 4 . Concrete
similar to the perimeter of the column section.
where ¢ is for tension-controlled members, 71 is the number of spearhead arms, and II' is the minimum length of each shearhead ann required to comply with requirements o{
411.13.3.2
Sections 41 1.13.4.7 and 41 I. 13.4.8.
reinforcement on one peripheral line that is geometrically
) F,
Vn
shall not be taken greater than 0.5
b" d.
411.13.3.3 The distance between the column face and the
first line of of stirrup legs that surround the columns shall not exceed d/2. The sparing between adjacent stirrups legs in the first line of shear reinforcement shall not exceed 2d measured in a direction parallel to a1coiumn face. The
spacing between the successive lines of shear reinforcement that surround the column shall not exceed dl2 measured in a direction perpendicular to the column face. 411.13.3.4 Slab shear reinforcement shall satisfy the anchorage requirements of Section 412.14 and shall engage the longitudinal flexural reinforcement in the direction being
411.13.4.7 The critical slab section for shear shall be perpendicular to the plane of the slab and shatl cross each shearhead ann at three fourths the distance [I,. - (c,/2)] from the column face to the end of the shearhead arm. The critical section shall be located so that its perimeter i>{) is a minimum, but need not be closer than the perimeter dellned in Section 41 L13. 1.2(1). 411.13.4.8 VI! shall not be taken greater than (I/3)
If:
bod, on the critical section defined in Section 41 J. J 3.4.7. When shearhead reinforcement is provided, VI! shall not be
taken greater than 0.58
ff bod
on the critical section
considered.
defined in Section 41 L13. 1.2(1).
411.13.4 Shear reinforcement consisting of steel J- or channel- shaped sections (shearheads) shall be permitted in slabs. The provisions of Sections 411.13.4.1 through
411.13.4.9 The moment resistance M,. contributed to each slab column strip computed by a shearhead shal! not be taken greater than:
41 L13A.9 shall apply where shear due to gravity load is
M
transferred at interior column supports. Where moment is transferred
to
columns, Section 41 L13.7.3 shall apply.
411.13.4.1 Each shearhead shall consist of steel shapes
fabricated by welding with a full penetration weld into identical arms at right angles. Shearhead arms shall not be interrupted within the column section. 411.13.4.2 A shearhead shall not be deeper than 70 ti mes
,
=¢a"v".(l 2 1/ '
_2) 2
(41142)
where ¢ is for tension-controlled members, 1} is the Humber of arms, and I,. is the length of each shearhead arm actually provided. However, M,. shall not be taken larger than the smallest of:
the web thickness of the steel shape.
1.
Thirty percent of the total factored moment required for each slab column strip;
411.13.4.3 The ends of each shearhead arm shall be
2.
permitted to be cut at angles not less than 30 degrees with the horizontal, provided the plastic moment strength of the remaining tapered section is adequate to resist the shear force attributed to the arm of the shearhead.
The change in column strip moment over the Icnflll fl'; and
3.
The value of M" computed by Eq. 411·4 '-
411.13.4.4 A!l compression flanges of'steel shapes shall be
located within O.3d of compression surface of slab. 411.13.4.5 The ratio 0;. between the stiffness of each
shearl1cad ann and that of the surrounding composite cracked slab section of width (C2 + d) shall not be less than 0.15. 411.13.4.6 The plastic moment strength Mil required for each arm of the shearhead shall be computed by:
¢ M"
=
i;d" , (t, t
ex,
';)1
411.13.4.10 When unbalanced moments are considcn',d, tlH" shearhead must have adequate anchorage to transmit MI' lo column.
4J 1.13.5 Headed shear stud reinforcement, P: ,i"i>,d perpendicular to the plane of a slab or footing, sll;l.il ue permitted in slabs and footings ill accordance with SC('iolls 411.13.5.1 through 411.13.5.4. The overall height 01 the shear stud assembly shall not be less than the thicknc.c:.,; of the member less the sum of: (I) the concrete cover Oil the top nexural reinforcement; (2) Ihe concrete cover ('. ~: lhe base rail; and (3) one-half the bar diameter of the ~( :ion flexural reinforcement. Where flexural !c: ion reinforcement is at the bottom of the section, a:-; in a [(I ,:ing, the overall height of the shear stud assembly Shil!i il()! be less than the thickness oCtile member less the SUII; tii: (I) I
(411-41)
Association of Structural En9ineefs of tile PhilipPines
CHAPTER 4 . Concrete
the co ncrete cove r all the bottom Oe:Ulral reinforcement; (2) the concrete cove r on the head of the stud; and (3) one-half the ba r diameter o f Ihe botlOrn flex ural rein fo rcement 411.13.5. 1 For the critical sect ion defin ed in Section 4 11.1 3.1.2. V" shall be computed using Eq. 411 ·2. with V, and V" nUl exceed in g
O.25A~ b"d
and
the spac ing o f the peripheral lines of headed shear stud rein fo rcement. III" /(b.,<) sha ll not be less than 0. 17
~.
411 .13.5.2 The spaci ng belween the column face a nd the first pe riphera l line of shear rein fo rcement sha ll nOI e xceed d12. The spaci ng be tween perip hera l lines of shear reinforcement . measured in a direct io n perpend icul ar 10 any facc o f the co lumn, sha ll be constant. For prestressed slabs or foo tings satisfying Sec ti o n 4 11.13.2.2 . this spacing shall not e xceed O.75d; fo r aJl ot her slabs ~lI1d footings, the spac ing shall be based o n th e value o f Ihc shear slI'ess due to fac tored sh eilI' forcl! and unbalanced moment at the cri tical sec tio n defin ed in Sec tion 4 I J .13.1 .2, and shall not exceed:
0.75d whe re maxim um shear stresses du e loads are less th an or eq ua l to O.5¢
2.
411.1 3.5.3
(0
factored
41 J.l3 .6.2 For slabs with shearheads. the ineffective portio n of the perimeter sh:t ll be one half of that defined in Seclion 4 11 . 13.6.1
10
411.13.7 T ransfer of M o m ent in Slab-ColullllI Co nnections 4 11.1 3 .7. 1 Whe re gmv ily load, wind, earthqua ke or otht l
lateral forces cause transfer of unba lanced moment. Mil, between 11 slab and a column, a frac tion yptu of the unba lilnced mo men t s ha ll be transferred by flcxu re in accordance wit h Section 4 13.6.3. T he remai nder of the unbalanced mome nt given by 'XMw shall be considered to be transfcrred by eccent ricity of shear about the cCIH roid of the cri tical section defi ned in Section 4 J 1.13.1.2 where:
411. 13.7.2 The shear sU'css res ulting fro m mo me nt transfer by eccentri c ity of shear sha ll be assu med to vary linearly abo1l1 the centroid of th e crit ical sections defi ned in Sec tion 4 J J .13. 1.2. The ma xim ulll shear stres s due to the factored shear force. V" and mome nt . Mil shall no t e xceed ¢ V'I:
For members wi thout shear rein forcement:
¢\', = ¢(~)
f.lctored
~.
(411·43)
y,. = ( I ·)t)
I.
ff,. ;and
0.50d where maximum shear st resses due loads arc greater than O.5¢
concentrated load or rcactlOn area and tangent to the boundaries of the openings shall be considered ineffecti ve.
O.66~ b"d.
respecti vely. V.I shall be calc ulated using Eq. 41 1- 15 with AI' equal to th e cross-sectio nal area of all the shear reinforce ment on One periphe ral line that is approximmcl y parall e l (0 the pc rimc te r of the co lumn section, whe re s is
I.
4·69
(4 11·44 )
b,. d
where V" is as defi ned in Section 411. 13.2. 1 or 4 11.13.2.2.
The
spacing betwcen adjacent shear reinforcement cleme nt s . measu red on the perimeter of the first peripheral line of s hear reinforcement , shall not exceed
2.
For members with shear rei nforcement other than she:lrhcads:
I' +V ) ¢Iv" ;::: ¢ - ' - - ' ( b .. d
2d.
(411-45)
411.13 .5.4 She
O. 1 7¢ A~ at
the c rit ica l
sec ti on located d/2 outside the ou termost peripheral line of shear re inforceme nt.
where Vc and Vs arc de ti ned in Secti o n 4 11.13. 3.1. If shear re inforce ment is prov ide d, the des ign sha ll take in to account th e vari ati on of shear s lre~s around th e column . The shear stress due to factored shear fo rcc and moment shall not exceed 0. 17(12
411.1 3.6 O penin gs in Slabs Whcn openings in slabs afe locmed at ::1 di stance less than 10 times the slab thickness from a concentrated load or reacl ion area, or when openings in n at Slilbs are located wi thi n co lumn strips as defined in Sec ti on 4 13, the critical slab sec tions for shear defined in Section 41 1. 13. 1.2 and Section 4 I 1. 13.4 .7 sholl be modi fi ed as fo ll ows:
4 11.13.6.1 For slabs withou t shcarheads. that pan of the pcrimeter of the c ritical section that is enclosed by stra ight li ncs
projc(,;ting
fro m
the
ccntro id
of
the
~
til
the c ritical sectioll localed
tin
outside Ihe olltermost linc o( the st ilTIiP legs that surround the colullIll.
411.U.7.3 Whe n shear reinforccment consisting of s teel 1nr channel-shaped sectiolls (shcarhcads) is provided. the sum of the shc
col umn. h
Nati on al S tru ctura l Code of thr-J P hilippines G: EcJ ilion Vo lumo 1
4 ·70
CHAPTEF!
~
. Concrete
Sections 41 Ll3.1.2 (I) and 411.13.1.3 shall not exceed
o331/1J.J/':
412.1 Notations
=- area of
= net
head ed dcfonncd bar, mlll
A,
111m2
bearing area of the head of stud . anchor bolt, or
;::: area
of
2
Ilonprcstrcsscd
IO!lgitudinal
tension
2
reinforce ment, mm ::::; toral cross-sectional
area
of
all
transverse
reinfo rcement which is within the spacing .\' and w hi ch c rosses the potential pJane of splilling through the reinforcement being developed , 111m2 = web width. Or diameter of circula r section, mm = small er of: (1) the distance from center of a bar or wire lO the nearest concrete su rface, and (2) onchal f the cenlcr-to-ccnter sp
being developed, mill. Sec Sec ti on 412.3.4
rI
;::: distan ce
i,
centroid of tension reinforce ment, mm :::: nominal diameter of bar, wire or prestressing strand, mm :::: specified compressive stre ngth of concrete, MPa
ff: /.'/
from
extreme compression fiber
to
= squa re root of specified compressive strengt h of
concrete, MPa :::: average spliu in g ten sile strength of lightweight <1ggreg.He conc rete, MPH = stress in prestressed rci nforecmcllI at nominal
1;.,
flexural strength, MPa strcss in prestrcs:;ed reinfn n:clllc lli (after allowance for all prestress losses), 'MPa = specifi ed yiel d strength of Ilonprcslf"cssed reinfo rcc ment , MPa = specified yie ld s.trc ngth [,. of transverse
II
= overa ll thickness or height o f member, 111111
K"
:::: transvcrse
f,,·
= cfTcctivc
reinforcement, MPa
/(1 1(/
l rlt"
Jdh
re inforcemen t index. Sec Sectio n 412.3.3 = A,r ~" I IOSII ;::; additional cmbedment length beyond cen terline of support or point of in nectio n, mill ;::; development length in tension of deformed bar, deformed wire, plain and deformed welded wire reinforcement , or prctcnsioncd strand, 111m :::: developm ent length in compression of deformcd bars and deformed wire, mm :::: development length in tCli sion of dcformcd b:tr or deformed wire with :t standard hook, measure/l from c ritical section to outside end of h ll. (straight e mbcdment length bc tween crilic;lI seeli -," and start o f hook (point of tangency) plus inside
Associa tion of Structural Engineers of the Philippines
CHAPTER 4 . Concrete
Idl
Mil
N
n
s
$...
V.,
p" ).
r:t
=
4·/1
412.3 Development of Defor med Bars and Deformed Wire in Tension 412.3.1 Developmentlcnglh, Iii. in lenns of diameter, db, for deformed bars and deformed wire in lension shall be dctcrmined from either Section 412 .3.2 or 412.3.3 and Ihe app licable modification factors of Section 412.3.4 and 4 12.3.5, but I,{ shall not be less th an 300 mil). 412.3.2 For deformed bars or deformed wi rc, lei sh.al! be as follows: ffi20 mill bars cd or ~pl i ce d 1101 less Ihan d~. cleilr cover nOI less Ilwn (I". ;md stirrups or lies (hroughout 1.1 not less lhall the code
(
minimum
f'V'~)d /.
2.1J.J"T:
01
Clear spacing of bars being developed or spliced nOI tess lhun 2dl , and clear cover .... ~.9Llcss than (h Olher
1 [_ I,.VI,VI, _ }
Ca~C"~
IA:t fj,
I
"
1i125 nun bars and larger
( /;/f,V', } lUff:
[ I,·",",
"
}I
lI:tff "
412.3.3 For deformed bars or deformed wi re. 1,/ shal l be: (4 12· 1)
412.20cvclopmen( of Reinforccmenl- General 412.2.1 Calculatcd tension or compression in reiMorcc: lllcnt eac h l-iccti on of structural concrete members shall be developed on each side of that section by embedment length, hook, headed deformed bar or mechanical device, or a co mbination thereof. Hoo ks and heads shall not be lIsed to develop hars in compression. al
412.2.2 Thc val ucs of
ff lIsed in Secti on 412 shaH not
exceed 8.0 MPa.
412.2.3 In addition to th is requirements in t:·.i :» secti on that affec t detail ing of reinforcements, structural integrity rcq llircmc.: nls o r Scc tion 407.14 shell l be sa tisfied .
in which the term 2.5. and
K
"
(Ch
+ K,r)l
= 40~
nOI
be lakc n grcater than
(4 12·2)
.'ill
wherc 1/ is thc number of bar:» or wi res being spliced or deve loped along the plane of spl illing. It shall be pefmi Hcd to lI :->C KIT = 0 as a design simpli ficatio n even if tr.lIlsvcrsc rei nforce ment is prescili. 412.3.4 The factors used in the expressions for developme nt of dcformed l>I'us ..tnd defor med wires ill tension in Section 412.3 arc as follows: I.
horizontal reinforcement is placed such that more than JOO rnm of fre sh conc rete is cast below
Where
N;·ltionai Structu !"(:li Co de of the PliilipPllW5
C;n· Edition
Volume I
4-72
CHAI'TEI< 4 - Concrete
the development JCIlgth or splice, situations, !f/I = 1.0; 2.
IjII :;:
1.3. For other
For epoxy-coated bars or wires with cover less than
3(h, or clear spacing less than 6db , VIe ::;: 1.5. For all other epoxy-coated bars or wires, VIe:::: 1.2. For uncoated and zinc-coated (galvanized) reinforcement, l.fIt ::;:: J .0. However, the product VI/Vie need not be greater than 1.7;
3.
Fc.>! ta20 mill bars and smaller and dcfonncd wires, ;:;:; 0.80. For 25 mill diameter and larger bars;
4.
'Ils:=
5.
Where lightweight concrete is used, A shall not exceed 0.75 unless fc, is specified (see Section 408.7). Where normal-weight concrete i~ used, A.::;: 1.0.
VIs
l.0; and
412.3.5 Excess Reinforcement Reduction in development length shall be permitted where rcinforcemcIH in a flexural member is in excess of that
required by analysis except where anchorage or development for 1;. is specifically required or the reinforcement is designed under provisions of Section 421.3.1.5 .. « ... «.... [(As.lequil"l:d}/(As.provided)]
412.4 Development of Deformed Bars in Compression 412.4.1 Development length for deformed bars and deformed wire in compression, {dc> shall be determined from Section 4! 2.4.2 and applicable modification factors of Section 4 I 2.4.3, but Ide shall not be less than 200 mIn.
412.5.2 For determining the appropriate spacing and COV':'::r values in Section 412.3.2, the confinement term in :·>'~[i'.m 412.3.3, and the Vir factor in Section 412.3.'1U), a ;)f bundled bars shall be treated as a single bar 01' a JiiliiiU ; .~J.' derived from the equivalent total area and having a (:,:ntn ,d that coincides with that of the bundled bars. 412.6 Development of Standard Hooks in Tension 412.6.1 Development length 1"'1 in 111m for deformed b;1!'~' . 'I tension terminating in a standard hook (see S(;clioll -'107 .~), shall be determined from Section 412.6.2 and the. modification factor or factors of Section 4JX6.) ~;:!;, : shall not be less than 8(h or less than 150 mill. 412.6.2 For deformed bars.
412.6.3 Length ldh in Section 412.6.2 shall be penniHed be multiplied by the following applicable factors:
Reinforcement in excess of that required by analysis ...................................................... (As required)/(A provided) j
2.
('
Reinforcement enclosed within spiral reinforcement not less than 6 mrn diameter and not more than 100 mOl pitch or within 12 mm diameter ties in conformance with Section 407.11.5 and spaced at not more than 100 111m on center . ..... 0.75
412.5 Development of Bundled Bars
412.5.1 Development length of individual bars within a bundle, in tension or compression, shall be that for the individual bar, increascd 20 percent for 3-bar bundle, and 33 percent for 4-bar bundle.
,;
t(:
1. For 36 mm bar diameter and smaller honks \'.'i(h sick. cover normal to plane of hook) not less than h.i Inm, and for 90~degree hook with cover 0)) . :,1' C.\\C; :;iu:: beyond hook not less than :-)0 Ifj)i)
............ n. 'j 2.
with). as given in Section 412.3.4 (4).
1.
shall be (024\11, i.l) II:;)
with IfIr taken as 1.2 for epoxy~coated reinfo!\'cmc!!L :Ul(i taken as 0.75 for lightweight concrete. For odlcr C:1:;'-.:5, ~o' and) shall be taken as J .0.
412.4.2 For deformed bars and deformcd wire, I'k shall be taken as the larger of (0.24f,/ Je.jT:) d" and (0.043/,) d"
412.4.3 Length ide in Section 412.4.2 shall be permitted to be multiplied by the applicable factors for:
idb
For 90-degree hooks of f1l36 mm bars an,' ~:i)r ::", 111::' are either enclosed within ties or stirrups I :'l"f)( "·
3. For ISO-degree hooks of 036 mm bars and :;malk: !h<:.
arc enclosed within ties or stirrups perpcn!l:culal io thr bar being developed, spaced not greate)" 1r!, ; ,1(;)).: 4.
Where anchorage or development r specifically required, reinforcement in required by analysis .. .... (As It":"
I,
(',
In Sections 412.6.3 (2) and 412.6.30). db is IL. ',"',ICltr c: the hooked bar, and the first tie or stirrup ,shall l"-lld(!:;e til· bent portion of the hook, within 2db of the m<:,ide of III bend. 412.6.4 For bars being developed by a stil:,,:< itO)K ;' discontinuous ends of members with side COV('T :md lnp (r:: bottom) cover over hook less than 65 mill . .]:(: ,; shall be enclosed within ties or stirrups peli bar being developed, spaced not greater th,nl :)\';, ilL ro[; i,:
Association of Structural Engineers of the Philippines
CHAPTER 4 . Concrete
The first tic or stirrup shall enclose the bent portion of the hook, within 2 (h of the outside of the bend, where db is diameter of hooked bar. For this case, the factors of Sections 412.6.3 (2) and (3) shaU not apply. 412.6.5 I-looks shall not be considered developing bars in compression.
effective
in
412.7 Development of Headed alld Mechanically
Anchored Deformed Bars in Tension 412.7.1 Development length for headed deformed bars in tension, llil' shall be delermined from Section 412.7.2. Use of heads to develop defonned bars in tension shall be limited to conditions satisfying (I) through (6): I.
Bar/, shall not exceed 415 MPa;
2.
Bar size shall not exceed f?J36 mm;
3.
Concrete shall be normal-weight;
4.
Net bearing area of head A brg shall not be less than 4A/!;
5.
Clear cover for bar shall not be less than lit/>; and
6.
Clear spacing between bars shall not be less than 4(h.
412.7.2 For headed deformed bars satisfying Section {dl shall be (0.191.f/~/ )d", where the value of J/ used to calculate shall
403.6.9, development length in tension
m:
i",
not exceed 40 MPa, and faclor !fI~ shall be taken as 1.2 for epoxy~coated reinforcement and 1.0 for other cases. Where reinforcemcnt providcd is in cxcess of that required by analysis, except where development of ;;, is specifically required, a factor of (AJ required)/(AJ" provided) may be applied to the expression for (It. Length {"I shall not be less than the larger of Sd/! and! 50 mm. 412.7.3 Heads shall not be considered developing bars in compression .
effective
in
412.7.4 Any mechanical attachment or devicc capable of developing!;. of reinforcement is allowed, provided that test results showing the adequacy of such attachment or device are approved by the building official. Development of reinforcement shall bc pcrmitted to consist of a combination of mechanical anchorage plus additional embedment length of reinforcement between the critical section and the mechanical attachment or device. 412.8 Development of Welded Deformed Wire
Reinforcement in Tension 412.8.1 Devc!opment length of weldcd deformed wire reinforcement in tension, ttl, in millimeters, measured from the point or critical section to thc end of wire shall be computed as the product of the dcvelopmcnt length td , from
4·73
Section 412.3.2 or 412.3.3, times welded deformed wire reinforcement factor, If/k" from Section 412.8.2 or 412.8.3. It shall be permitted to reduce the development length in accordance with Section 412.3.5 when applicable, but id shall not be less than 200 mm except in computation of lap splices by Section 412.19. When using the welded deformed wire reinforcement factor, If/w, from Section 412.8.2, it shall be permitted to use an epoxy-coating factor, If/(, of 1.0 for epoxy-coated welded deformed wire reinforcement in Sections 412.3.2 and 412.3.3. 412.8.2 For welded deformed wire reinforcement with at least one cross wire within the development length, ld and not less than 50 mm from the point of the critical section, the welded deformed wire reinforcement factor shall be the greater of:
but need not be taken greater than 1, where s is the spacing between the wires to be developed. 412.8.3 For welded deformed wire reinforcement with no cross wires within the devclopment length or with a single cross wire less than 50 mm from the point of the critical section, the wire fabric factor shall be taken as 1, and the deve!opment length shall be determined as for deformed wire. 412.8.4 When allY plain wires, or defonned wircs larger than 16 mm diameter, are present in the weldcd deformcd wire reinforcement in the direction of the development length, the reinforcement shall be developed ill accordance with Scction412.9.
412.9 Development of Welded Plain Wire
Reinforcement in Tension 412.9.1 Yield strength of welded plain wire reinforcement shall be considered developed by embedment of two cross wires with the closer cross wire not Icss than 50 mm from the point of the critical section. However, the development length fd , ill millimeters, shall not be less than:
(412·3)
Where ttl is measured from thc point of the critical section to the outermost cross wire, s is thc spacing between the wires to be developed, and .,tas given in Section 412.3.4 (4). Where reinforcement provided is in excess of that required, this length may be reduced in accordance with Section 412.3.5. Length td shall not be less than 150 mm except in computation of lap splices by Section 412.20.
National Structural Code of the Philippines
6!11
Edition Volume 1
4- 74
CHAPTEr, 4 - Concrete
412.10 Development of Prestressing Strand 412.10.1 Excep t as provided in Section 4 I 2. 10.1.1, seven· wire s trand shall be bonded beyond the critical section , a di stance not less than: f
"
= ( i ") d 21
+(
i p,
II
-
7
i"
)d "
(412-4)
Expressions in parentheses are used as co nslants wllhou( units, where db is strand di ameter in millimeters. and.!;,.. and fJr
412.1 I.J Devclopment of tension rcinforccn1cIlI by bending across the web to be anch ored or mad e con tinuou s with fcinrorccm~nl on the opposite fnee of me mber shall be perlnitlcd. 412.11.2 Critical sect ions for devclopment o f reinforcement in nexural mcmbers nfe at points of maximum stress and at points wi th in the spa n whe re adjacent reinforcement termina tes or is ben I. Provisions of Section 412.12.3 must be satisfi ed . 412.11.3 Reinforce mcnt sh
412.11.5 Flexural reinforccment shal l not be tennin(l.lcd in a tension zone unless one of the following conditions is satisfied: 412.11.5.1 V. at the eu tofT point docs not exceed (213) 9>V, .
412.11.5.2 Stirrup area in excess of that requircd for shear and torsion is provided along each terminated bar or wire over a di stance from the tenn ination poi nt eqllal to three fOUl1hs the effecti ve depth of member. Excess slirrup area A,_ shall not be less than 0.4 I b,..s i" _Spacing s shull not exceed dl(8/3b) where Pb is the ratio of area of reinforcement cut off to total area of tension reinforcement at the sec tion. 412.11.5.3 For 1lI36 mm bar alld smaller, continuing rei nforcement provides dou ble the area required for flexure at the cutoff point and V. docs not exceed (3f4)9>V,. 412.11.6 Adequate anc horage shall be provided for tensiOIl reinforcement in nex ural members where reinforce ment stress is not directl y propo rt ional to moment. such as sloped, stepped or tapered foo tings; brackets; deep flex ural members; or members in which tension rei nforcemen t is not parallel to compression facc. See Sections 412.12.4 and 41 2. 13.4 for deep fl ex ural members . 412.12 Development of Positive Moment Reinforcement
412.12.1 A t least one third the positive moment reinforcement in simple members and one fourth the positive moment reinforcement in con tinuous members shall extend along the sa me face of member into the sup port. In beams. sllch reinforce men t shall ex tend illlo the suppOrt at least 150 mill. 412.12.2 When a flexural membe r is part of a primary lateral-load-resisting system, positive moment rein forcement required to be extended into the support by' Section 412. 12. I shall be anchored to develop the specified yield strength/I. in tension at the face of suppo rt.
412.12.3 At simple supports and at points of inncction. positive moment tension reinforcement shall be limited to a diameter such that ld computed for 1;. by Section 412.3 satisfies Eq. 4 12-5, except Eq. 41 2-5 need not be sati sfi ed for reinforcement terminating beyond center line of simpk SUPPOf1S by a standard hook or a mechani cal anchorage at Icast cq ui va lent to a stand ard hook. M
412.11.4 Conti nuing reinforcement shall have an embedment length Il ot less than the development length //( beyond
the point
reinforce ment is
110
where bent
or
terminated
I,,$"+f VII
"
tension
longe r required to resist ncxure.
Association of Structural Engineers of the Philippines
CHAPTER
where:
:\ M" is calculated assuming all reinforcement at the section to be stressed to /y; Vu is calculated
at
~
. Concrete
4·15
412.14.2.1 For III I 6 mm bar and MD 200 wire, and smaller, and for 000 mm and 1lI25 mm bars wil h !,., of 280 MPa or less, a standard stimlp hook around longitudinal reinforcement.
the section;
fa
at a support shall be the embedment length beyond center of support; or
fa
at a point of inOcction shall be limited to the effective depth of member or l2(h. whichever is greater.
An in crease of 30 percent in the value of M,/Vu shall be permitted when the ends of reinforccmclH are confined by a compressive reaction.
412.12.4 AI simple suppons of deep fl exu ral members, positive moment te nsion reinforcement shall be anchored to develop the specified yield strength h in tension at the face of support except that jf design is canied out using Section 427, the positive moment tension reinforcement shall be anchored in accordance with Section 427.4.3. At interior supports of deep beams, positive moment tension reinforcement shall be continllous or be spliced with that of the adjacent spans. 412.13 Developmenl of Negative Moment Reinforcement
412.13.1 Negative moment reinforcement in a cOlllinuotls, rcs!rained or cantilever member, or in any member of a rigid frame, shall be anchored in or throu gh the supporti ng member by embedmcm length, hooks or mecha nj caJ anchorage. 412.13.2 Negative moment reinforcement shall have an embedment length into the span as required by Sect ions 4 12.2 an"412.11.3. 412.13.3 At least one third the total tension reinforcement provided for negative moment at a suppon shall have an embedment length beyond the point of inflection not less than effective depth of member, 12(h, or 1116 the clear span, whichever is greater. 412.13.4 AI interior supports of deep flexural members, negative moment tension reinforcement shall be continuous with that of the adjacent spans.
412.14 De\'elopmenf of 'Veb Reinforcement 412.14.1 Web reinrorcement shall be carried as close to comprc~s·i{)n
412.14.2.2 For !ll20 rnm and 025 mill stirrups with.!;.( greater tiian 280 MPa, a standard stirrup hook around a longitudinal bar plus an embedment between mid-height of the member and the outside end of the hook equal to or grealer.lhan 0.17dJ,.,
A.[f: 412.14.2,3 For each leg of welded smool h wire fabric forming simple U-stirrups, either:
I.
Two longitudinal wires spaced at a 50 mm spacing along Ihe member al Ihe lOp of Ihe U; or
2.
One longitudinal wire located not marc than d/4 from the compression face and a second wire closer to the compression face and spaced not less than 50 mm from the first wire. The second wire shall be permitted to be localed on Ihe slirrup leg beyond a bend, Or on a bend with an inside diameter of bend not less than 8db.
412.14.2.4 For each end of a single·leg slirrup of welded pJain or deformed wire fabric, two longitudinal wires at a minimum spacing of 50 mm and with the inner wire at least Ihe grealer of d/4 or 50 mm from mid·deplh of member dI2. Outer longitudinal wire at tension face shall not be farther from the face than the pOl1ion of primary flexural reinforcement closest (0 the face. 412.14.2.5 In joist construction as defined in Section 408.12, for 12 mm diameter bar .llld MD 130 wire and :o; mallcr, a standard hook. 412.14.3 Between anchored ends, each bend in the continuous portion of a simple U~s tirnIp or multiple Ustirrups shall enclose a longitudinal bar. 412.14.4 Longiludinal bars ben I 10 acl as shem' reinforcement, if extended into a region of tension, shall be con tinuous with longitudinal reinforcement and, if extended into a region of compression, shall be anchored beyond ll1id~ depth d/2 as specified for development length in Section 412.3 for Ihal parI of!, required 10 satisfy Eq. 411·17. 412.14.5 Pairs of U-stirrups or tics so placed as to for m a closed unit shall he consi de red properly spl iced when length s of laps arc 1.31//. In members .It Icast 450 111m deep. such splices with AJ,./ not more than 40 kN per leg may be co n$ide red adequate if stirnlj) legs extend the fu ll avai lable depth of member.
412.14.2 Ends of single leg, simple U- or multiple Ustirrups :-ohall be anchored as required by the following:
National Structural Code of Ule Philippines 6
th
Edition Volume 1
4-76
CHAPTER 4 - Concrete
412.15 Splic", of Reinforcement - Gencral
412.15.1 Splices of reinforcement shall be made only as required or permitted on design drawings or ill specifications, or as authori zed by Ihe engineer-or-fecon!. 412.15.2 Lap SI)li ces
412.16 Splices of Deformed !lars and Deformed Wire in Tension
412.]6.1 Minimum lengt h of lap for tension lap spli ces :.haIl be flS required for Class A or B splice, but not less than 300 mill, where:
412.15.2.1 Lap splices shall nOI be used for bars larger than 36 111m diameter. except as provided in Secljolls 412.17.2 and 415.9.2.3. 412.15.2.2 Lap sp lices of bars in a bundle shall be based on (he lap splice length required for individual bars within the bundle, increa<;cd in accordance with Sec ti on 4 12.5. Individual bar splices within a bundle shall nOI overlap. Entire bundles shall not be lap spl iced. 412.15.2.3 Bars spliced by non-conlact lap spl ices in flexural members shall not be spaced transversely farther apart than one the requi red lap splice lengt h. or 150 mill.
fim,
412.15.3 Mechanical and Welded Spliccs 412.15.3.1 permiued.
Mechani cal
and
we lded
splices
shall
be
412.15.3.2 A full mechanical splice shall develop in tension or compression . as required. atlcast 1.25J;. of Ihe bilr. 412.15.3.3 Except as providcd in (his cha pler, all weldin g !ihall confonn to "Strife/ural W{~/ding Code· Reinforcing Sleel" (ANSIJA WS D 1.4). 412.15.3.4 A full-welded sp lice shall develop al leasl 1.25 !, of the bar. 412.15.3.5 Welded splices and mechanical connections not meering requirement s of Section 412./5.3.2 or 412.15.3.4 ru-e allowed only for rnl6 111m ba rs and smaller and in accordance with Section 412./6.5.
412.15.3.6 Welded splices and mechanical conncctions shall maintain the clearance and cove rage requirements of Secti ons 407 .7 and 407.8.
Class A spl icc
I.Old
C lass IJ splice
1.31"
where Id is calculated in accordance with Section tj·J2.3 to develop 1;. , bUl without the 300 mm minim ull1 u! .\ :ection 412.3.1 and wi thout the modi fi cation fa<.:tor of Sec tion 4 12.3.5. 412.16.2 Lap splices of deformed bars and deforn1("d wire in tension shall be Class B splices except that Class A splices may be used when:
I.
The area of reinforcement provided is at leasl twice that required by ana lysis over Ihe entire length of the splice; and
2.
One half or less of the total reinforcemcnt is spliced within th e required lap length .
412.16.3 When bars of differen l size arc lap "pl iced in ten sion, splice length shall be the larger of Id of larger bar and tension Jap splice length of smaller bar. 41 2.16.4 Mechanical or welded splices used where area of reinforcement provided is less than twice that req uired by analysis shall meet requirements of Sections 412. 15.3.2 or 412.15.3.4.
412.16.5 Mechani cal or welded splices not meet.ing the requiremenl" of Secli ons 412.15.3.2 or 412.15 .3 .4 shall be permitted for 16 mm diameter bars and small er if the requirements of Secti ons 412.1(\.5 .1 ulcough 412.16.5.3 arc met: 412.16.5.1 Splices shall be staggered alieaSl600 mm.
412.16.5.2 In computi ng the tensile forces Ih:l{ can be deve loped at eac h section, the spliced reinforccrnr.!li ':lfrSr. sll
Association of Structural Engineers of tile Philippines
CHAPTER 4 . Concrele
412.16.6 Sp li ces in tension lie members sha ll be m ade with a fuJI mechani cal o r full welded splice in accordance with Secti o ns 412.15.3 .2 or 412.15.3.4 and splices in adjacent bars shall be staggered at least 750 mill. 412.17 Splices of Deformed Bars in Compression 412. 17.1 Com prcssion lap splice length shall be 0.07 1fA . . for 1,. of 420 MP. or less, or (0.13 I, - 24) d. for 1,. g,,;,ner thall 4 15 MPa. but nol less than 300 mill. For fo less than 2 J M P'l, length of lap shall be increased by one third. 412.17.2 When bars of different size are lap spli ced in compress io n, splice length shall be the larger I",., of la rger
bar Hl1d co mpression lap splice length of smaller bar. Lap spli ces of 42 and 58 mill diamete r bars to 36 mm di ameter ;md smaller bars shall be pcr milted . 412. 17 .3 Welded sp lices or mechanical connect ions lIsetl in compression shall meet requirements of Sections 4 12. 15•.3.3 an d 4 12 . 15.3.4. 412.17.4 E nd-Bearing Splices
Tn bars requ ired fo r co mpression (J·n])'. transmissio!l of compressive stress by bearing of square cut ends held in concentric co ntact by a suita ble device shal! bc pcnnittcd.
4·77
if one half or fewer of the bars are spl iced at an y sec tion and alternate Jap splices are staggered by
'd'
412.18.2.3 Where the bar stress due to factored loads is grea ter than 0.5 h in te nsio n, lap splices shall be Class B
tension lap splices. 412.18.2.4 In tied rei nfo rced com press ion members, where lies throughou t the lap splice length have an effective area not less than 0.0015hs, lap splice le ngt h shall be permitted to be Illu lti plied by 0.83, but lap length shall not be less th an
300 mill. Tie legs perpend icul ar to dimension" shall be lI sed in determining effecti ve area. 412.18.2.5 In spirally reinforced compression members, lap splice length of bars within a spiral sha ll be permitted to be multipl ied by 0.75, but lap le ngth shall not be less than 300
mm . 412.18.3 Welded Splices o r Mechanical Connectors in Columns
Welded splices or mechanical connectol"!i in columns sha ll meet the req uireme nt s of Secti on 4 12.15.3.3 o r 4 12. 15 .3 .4 .
412.17.4.1
412.1 7 .4.2 Bar cnds shall (ermin,lIc in nat surfaces wi th in 1.5 degrees of a right ang le to the u;.; is of the bars and shall be filled within 3 degrees of fu ll bearing after assembly. 412.17.4.3 End-bearing splices shall be used only in me m hers containing closed tics. closed sti rrups or spirals.
412.18.4 End-hearing Splices in Columns
End-beari ng spli ces complying wi th Secti on 41 2.17.4 shall be permitted 10 be used fo r colum n bars stressed in co mp ression provided the splices are staggered or add iti onal bars nrc provided at splice locat ions. The conti nui ng bars in each fa ce o f Ihe column shall have a tensile st rength, based 0 11 the specified yield strength h., not less tha n 0.25/1, limes the area of the vert ical rein fo rce mcnt in that facc. 412.19 Splices of \-\'cldcd Dcfornwd Wire
412.18 Spedal Spikes Requiremcnts for Columns
Reinforcemcnt in Tension
412.HU Lilp s pl ices, bult we lded spi kes, mcchnni cal co nnecti ons or end-beari ng splices shall be used wi th the limi tations of Sect ions 4 12. J 8.2 through 412. ! 8.4. A spl ice shnll satisfy req uiremcnts for all load cOJllb in:ltiOlls for the column.
412.19.1 Mi nimulll lengt h o f lap fo r 1,1)) splicc..... o f wel ded de formed wi re fabl;c measu red be tween the ends o f each fabric sheet shall not be less th an 1.3/d or 200 mm. and the ovcrhlp measured between ou termos t eros!'; wi res of each fabric sheet shall not be less than 50 mill, I" shall be the deve lop men t le ngth for Ihe .specificd yield stre ngth 1.~. in accorda nce with Secti on 4 12 .R.
4 J 2.1 H.2 Lap Spikes ill Columns 4q.1H. 2.1 Where th e bar stress du e (l factored l()l1d ~, is r ()!llprl~ss i ve . lap sp lices sha ll co nform 10 S~~c ti o ns 4! 2. 17. 1 and 412.17 .2. and where :lp pl it~ab!e, to Sec tio n 4 J 2.1 X.2 ,ll or "II ~ . I K25 .
• (.lctOfcd loads
41 2. 1X.2.2 Wh(:r~~ Ihe hal' Sl ress due to is tensi le lind dncs nol exceed () .~r.. in tension. l;l P splices sha ll he Class B tcnsioll lap "pikes if more tha ll nne half of the hars arc :-,plin'd
412.19.2 Lap spli ces of wel ded deform ed wire rei n foru' lllcnt , with no cross wires within the lap splice Ic.n gth . shall be determined as for (kf"onn cd wire.
412.19.3 Where any pl aul wires, or de formed wi res large r than MD 200, arc prcsent in the welded deformed wire reinforcemcnt in the direction or {ilc lap !\plice or where welded ddonncd wire reinforcelllent is l"lp spliced In we lded plain wirc reillfon:cmcnt, the rein forcement sha ll he I.. p spliced in aCC() rdil llCc with Seclion 41 2.20. nl
Nafiondl SIIUctt ll"i" ll Co cle of the PhilipPIi"l (-!-s G Edition Vol\l1"t1(·: 1
4·78
CHAPTEI'4·· Concrete
412.20 Splices of Welded Plain Wire Reinforcement in
Tension Minimum length of lap for lap splices of welded plain wire reinforcement shall be in accordance with the foHowing: 412.20.1 When area of reinforcement provided is less than twice that required by analysis at splice location, length of overlap measured between outermost cross wires of each reinforcement sheet shall not be less lhan the largest of one spacing of cross wires plus 50 mm, or less than 1.5 id , or ISO mm, Id shall be the development length for the specified yield strength/" in accordance with Section 412.9.
413.1 Notations
bl b2
C 412.20.2 Where area of reinforcement provided is at least twice that required by analysis at splice location, length of overlap measured between outermost cross wires of each reinforcement sheet shall not be less than 1.5 1,1, or 50 mm, /,/ shall be the development length for the specified yield strength/;. in accordance with Section 412.9.
::: dimension of the critical section bo measured in the
direction of the span for which moments arc determined, mm ::: dimension of the critical section bo measured in the direction perpendicular to /)1, mm ::: cross-sectional constant to define torsionnl properties of slab and beam. See Section 413.7.4.) J
I(1_O.63.::.)x y y 3 (.'1
("2
fie" E("J h
h
/.,
= 'dimension of rectangular or equivalent rectanguJa:' column, capital, or bracket measured in the direction of the span for which moments arc being determined, mm = dimension of rectangular or equivalent rcctangulai column, capita! or bracket measured transverse to the direction of the span for which moments arc being detennined, tnm ::: modulus of elasticity of beam concrete, MPa = modulus of elasticity of slab concrete, MPa ::: overall thickness of member, mm = moment of inertia about centroidal axis of gross section of beam as defined in Section 413.7.1.6 = moment of inertia about centroidal axis of gro:;:) section of slab defined for calculating fXt and /3( , mm
KI 1/1
4
::: h.1/12 times width of slab defined in notations aand PI ::: torsional stiffness of torsional member; moment per 'unit rotation ::: length of clear span in direction that moments arc being determined, measured face to face (i~' SUpp0I1S
II 12
M"
Mil (/1<
\/,
\
= length of span in direction that moments are being determined, measured center to center of support:: ::: length of span transverse to I" measured center to center of supports. Sec also Sections 413.7.2.3 ill::] 413.7.2.4 ::: total factored static moment ::: factored moment at section = factored load per unit area ::: nominal shear strength provided by concrete. See Sectioll 411.13.2.1 ::: factored shear rorce at section ~ factored dead load per unit area ::: factored live load per unit area ::: shorter overall dimension of rectangular parl cross section, mill
AssocicltlOll of Structur("d EnDineers of the PhilipPines
CHAPTEfi 4 - Concrete
y
a
::: longer overall dimension of rectangular part of cross section, mill ~: ratio of Ilexural stillness of beam section to flexural stiffness of a width of slab bounded lateral!y by cenler lines of adjacent panels (if any) on each side of the beam = E 10',.,/ ,
al a? ~
= ain direction of I, :::: in direction of t2 = ratio of torsional sl:ffness of edge beam section to flexural stiffness of a width of slab equal to span length of beam, center to center of supports = _s"C::_ n~J,
'JJ
y"
p
p" ¢
::: fraction of unbalanced moment transferred by
flexure at slab-colullln connections. Sec Section 413.6.3.2 ;:: fraction of unbalanced moment transferred by eccentricity of shear at slab-column connections = I - y; :::: ratio of nonprcstressed tension reinforcement = reinforcement ratio producing balanced strain conciitions = strength reduction factor
413,2 Scope 413.2.1 The provisions of this Section shall apply for design of slab systems reinforced for flexure in more than one direction, with or without beams between supports. 413.2.2 For a slab system supp0I1ed by columns or walls, the dimensions <.', and C2 and the clcar span til shall be based on an effective support area defined by the intersection or the bottom surrace or the slab, or of the drop panel if there is one, with the largest right circular cone, right pyramid, or tapered wedge whose surfaces are located within the column and capital or bracket and arc oriented no greater than 45 degrees to the axis of the column. 413.2.3 Solid slabs and slabs with recesses or pockets made by permanent or removable fillers between ribs or joists in two directions arc included within the scope of this Section. 413.2.<-! Minimulll thickness of slabs designed in accordance with tll;s Section shall be as required by Section 409.6.3.
4-79
413.3 Definitions 413.3.1 Column strip is a design strip with a width on each side of a column center line equal to 0.251 2 or 0.251" whichever is less. Column strip includes beams, if any. 413.3.2 Middle strip is a design strip bounded by two column strips. 413.3.3 A panel is bounded by column, beam or wall center Jines on all sides. 413.3.4 For monolithic or fully composite construction, a beam includes that portion of slab on each side of the beam extending a distance equal to the projection of the beam above or below the slab, whichever is greater, but not greater than fOLlr times the slab thickness. 413.3.5 When used to reduce the amount of negative moment reinforcement over a column or minimum required slab thickness, a drop panel shall:
I.
Project below the slab at least one-quarter of the adjacent slab thickness; and
2.
Extend in each ciirection from the centerline of SUppOlt a distance not less than one-sixth the span length measured from center-to-center of supports in that direction.
413.3.6 When lIsed to increase the critical condition section for shear at a slab-column joint, a shear cap shall project below the slab and extend a minimum horizonlal distance from the face of the column that is equal to the thickness of the projection below the slab soffit.
413.4 Slab Reinforcement 413.4.] Area of reinforcement in each direction for two-way slab systems shall be determined from moments at critical sections, but shall not be less than required by Section 407.13.2.1. 413.4.2 Spacing of reinforcement at critical sections shall not exceed two times the slab thickness, except for portions of slab area of cellular or ribbed construction. In the slab over cellular spaces, reinforcement shall be provitj'~d as required by Section 407.11
1h
National StllJCturai Code of tile PhilipPines 6 Edition Volume '1
4·80
CHAPTEI1 4 . Concrole
Figure 413-1 Extensions for Reinforcements in Slabs without Beams (Sec Section 412.! 2. J for reinforcement extension int n supports)
STRIP
LOCATION
MINIMUM As AT SECTION 0
WITH DROP PANELS
WITHOUT DROP PANELS
0,331n
0,301n 50% TOP REMAINDER COLUMN STRIP
BonOM
100% least two bars
or wires shall 1111 conform 10 13,3,6.5
Splices shall be permitted in this region I
TOP MIDDLE STRIP
0.211• .
0.22(.
0.221. 100%
50% BOnOM
150 mm
Max. 0.151.
Max. 0.151.
REMAINDER
Clear span oln
Cl
Face of support Cenler to center
It Extenor support (No slab continuity)
Center to center span
It Intenor support (Continuity provided)
I\ssociatlon of Structural Ellqlllccrs of 1111: PI-lilIPPIJ'lC':',
Ext 101
(No s!ab ml1lll'''lII,
CHAPTER 4 - Concrele
413.4.3 Positive moment reinforcement perpendicular to .\ discontinuous edge shall ex tend (0 the edge of slnb aud ha ve embedment, straight or hooked, at leasl 150 !l1l11 in spandrel beams, columns or walls. 413.4.4 Negative moment reinforcement perpendicular to
4-81
4 13.4.8 Delails of Reinforcement in Slabs without Beams 413.4.8.1 In addition to the other requirements of Section 413.4, reinforcement in slabs without beams shall have min im um cxtensions as prescribed in Figure 41 3- 1.
II
discontinuolls edge shall be bent, hooked or otherwise llllchored, in spandrel beams, co luillns or walls, to be developed at f;lce of StJPPOJ1 according to provisions of Section 412.
413.4.8.2 Where adjacent spans are unequal, extension of ncgative moment reinforcement beyond the face of support as prescribed in Figure 4 I 3-1 shall be based on requiremcnts of longer spa n.
413.4.5 Where a slab is nOI s li pPol1ed by a spandrel beam or W,lJl at <1 discontinuous edge or where a slab cMti levers beyond [he support, anchorage of reinforcement shall be permitted within the slab.
413.4.8.3 Ilelll bars shall be pennilled only when dcplhspan ratio pennils use of bends 45 degrees or less.
413.4.6 At exte rior corners of slabs su pported by edge walls or where onc or mOre edge beams have a value of greater than 1.0, lOp and bottom slab reinforcement shall be provided at exterior comers in accordance wi th Secti ons
0.,
413.4.6. llhrough 413.4 .6.4 :
413.4.6.1 Corner reinforcement in both top and bottom of slab s hall be sufficien t to resist a moment equal 10 the maximulTl positive moment (per meIer of width) in the slab panel.
413.4.6.2 Tile lllomelH shall be assumed to be about an axis perpe ndi cular to the diagonal from the corner in the lap of the slab and about an axis parallel to the diagonal from the corner in the bottom of the slab. 413.4 .6.3 Corner reinforce ment shall be provided for a distance in each direction from the corner equal 10 one-fifth th e longer span.
413.4.6.4 ConteI' r~inrorcc mcill shall be pl<1ccd parallel 10 the diagollul in the lOp of the slab and perpendicular [0 the diagonal in the hallom of the slab. Alternatively, the special reinforcement Sh ;'l ll be placed ill two layers pilrallcl 10 the sides of the slab in both the top and h0l10111 of the sl ab . 413.4.7 When n drop panel is used to reduce the a!llount of negative moment reinforcemcnt over the column of a flat :-;Iab, the tiilllCIlSiolls of thc drop panel shall be in accordance wilh Section 41 :t3.5. In computing required slab rcinforcclllcllI. the thickness of the drop panel below the shih shall not be ilSSlIlIlCtl 10 be greatcr than one-quar:er Ik <.I ist,mcc from lhe edge or drop pa nel 10 the r
413.4.8.4 In framcs where two-way slabs act as primary members reSisting lateral loads, lcngths of reinforcement shall be delcnnined by analysis but shall not be less than those prescribed .in Figure 413-1. 413.4.8.5 All bo([om bars or wires within the column strip. in each direction, shall be continuous or spliced with Class B splices or with mechanical or welded splices satisfying Seclion 412.15.3. Splices shall be located as shown in Figure 413-1. At least two of the column strip bOllom bars or wires in each direction shall pass within thc regio n bounded by the longitudinal reinforcement of the column and shall be anchored at ex terior SUpp0l1S .
413.4.8.6 In slabs with shearheads and in lifl·slab construclion where it is not practical to pass the bottom bars reql~red by Section 413.4.8.5 Lhrough the column, at least (wo bonded bOllom bars or wires in each direction shall pass through the shea rh ead or lifting collar as close to the column as pract icable and be co ntinuous or spliced with a Class A splice. At ex terior columns, the reinforcement shall be .mchored at the shearhead or lifting foHnL 413.5 Openings in Slab Systems
413.5.1 Openings of any siz.e shall be permitted in slab sys tems if shown by analysis lhal the desi gn strength is at least equal 10 the sirength considering Sections 409.3 and 409.4, and that all serviceabil it y condi tions. including the s pecified Iimil.'\ on deflcclions .• Ire mel.
413.5 .2 As (11) altcrnate In spcciill analysis ns required by Section 413 ..1 .1, openings shall be permitlcd ill slab syslems wiLhout bt. . ams only in ,lccnrdancc with Ihe follow i ng: 413.5.2.1 Ope nings or
4 -82
CHAPTEIi 4 - Concreto
413.5.2.2 In the area co mmo n to intersecting column stlips,
flot more than onc-eighth the width of column strip in either span shall be interrupted by openings. An amou nl of reinforcement equ ivalent to thaI intermptcd by an opening sha ll be added on the sides of Ihe opening. 413.5.2.3 In the area common to one column strip and one middle strip, not more than one-fourth the reinforcement in eilher strip shall be inl efnlpled by openings. An nmount of reinforcement cquivalcl; : to that interrupted by an open ing shall be ndded 0 11 the sides of the opening.
413.5.2.4 Shear requirements of Section 411.13.6 shall be satisfied. 413.6 Design Procedures
onc~half
slab or drop panel thickness (1.511) outside opposi te faces of the column or c"pilal, where Mil is the moment to be transferred and (4 13- 1)
413.6.3.3 For unbalanced moments about an axis pa rallel to Ihe edge at exterior Supp011S. Ihe value of Y/ by Eq. 413~ 1 sha ll be in accordance with Ihe following: I .• For edge columns with unb~llanced moments about an
an axis parallel to the edge, It = 1.0 provided that Vu at an edge support docs not excced O.75¢V,. or al a comer support does not exceed 0.5q,V,..
2. For unbalanced moments al interior SUppOI1S. and for 413.6.1 A slab system shal! be desig ned by any procedu re snl is fyi ng conditi ons of equilibrium and geomet ric compati bilit y, jf shown that the design strengt h at every section is at l ea~t equal to the required strength set fo nh in Sec ti ons 409.3 and 409.4 and that all serviceab ility co nditi o ns. including limits on defl ec ti ons, arc mel. 413.6.1.1 Desig n of a slab system for gravity loads in clud in g th e slab and beams. if any, between supports and supporting co lumns or walls forming orthogo na l fr amcs. by ei lhe r the Direct Design Method of Section 413.7 or the Equiva le nt Frame Method of Section 413 .8, shall be pc nn iucd . 41 3.6.1.2 For lateral loads. analysis of frames shall takc into nccount effects of cracking and reinforcemcnt on stiffness of frame me mbers.
4) 3.6.1.3 Combining the resuils of the gravity load unalysis with the results of the latcral load analysis shall be pcrmillcd.
edge co lumns with unbalanced momcnts about an axis transverse to the edge, inc rea se '}f to as much as 1.25 ti mes the value from Eq, 413 ~ 1 , but not more than '}j= 1.0, provided that V" at the su pport docs !lot exceed O.4
413.6.3.4 Concentration of rcinfo rceme nt over {he col um n by closer spaci ng or additional rein forcemc lll shall be used
to rcsist moment 011 the effcclive slnb width defined in Section 413.6.3.2.
41 3.6.4 Design for tranxfcr of IO:lci fmm sl;'!h to sllppon ing columns or wiJlIs through shcm' ;lI1d torsion xll.1l1 he in accordance with Section 41 I. 413.7 Di rect Design Method
413.6.2 Thc slab and beams. if any, betwccn suppmls shall be proportioned for factored moments prevailing al evcry section.
413.6.3 When gravity load. wind , earthquake or other latcr,,1 forces c
413,6.:t l Fra ction of unbalanced moment 110t transferred by ncx.ure shall he transfcrred hy eccentric it y of shc:lr in accordance with Secl ion 4 11 . 13.7. 4J3.6,3 .2 A rnlctioll of thc unhahlllccd momcn l given by Yr M" sha ll be considered to be Inlnsfcrred hy flexur e
413,7.1 Limitati on s Design of slab xys rcms within the following limil
413.7.1.1 There sh;:tl i he a mi nimum of Ihree c'OIui m',,"
sp.IIlS in each direction. 4[3.7. 1.2 P:lIlcis shall be rectangular. with it ratio or lungc'" cenlcr~lo ~cc l1lcr supports within it pant:! no; greater than 2.
10 shorter span
413.7.1.3 Successive span lengthS ccntcHo·ccnh-r SI! l'Y":·· ill each directio n s hall not differ hy more tlt'"II1 olH>lh ild i~ .. ; longer sp.m.
wi th in an cfl'l.!ctivc slab width between lines thaI arc one and
Associ8tlon of Structura l Engll'1ecl's of the r:)hilipPlnes
CHAPTER 4 . Concrele
4·83
413.7.1.4 Offset of columns by a maximum of I() percent of the span in direction of offset from either axis between center lines of successive columns shall be permitted.
polygon-shaped supports shall be treated as square supports with the same area.
413.7.1.5 All loads shall be due to gravity only and uniformly distributed over <1n entire panel. Live load shall not exceed two times dead load.
413.7.3
413.7.1.6 For a panel with beams between supports on an sides, the relative stiffness of beams in two perpendicular dircclions. (413-2)
Neg::ltive and Positive Factored Moments
413.7.3.1 Negative factored moments shall be located at face of rectangular supports. Circular or regular polygonshaped supports shall be treated a,s square supports with the same area. 413.7.3.2 In an interior span, total static moment Mo sha!l bc distributeci'
Negati ve factored moment shall not be less than 0.2 nor greater than 5.0, whereOfJ and Qj2 are calculated in accordance with Equation (413-3). (413-3)
Positive factored moment
................... 0.35
413.7.3.3 In an end span, total factored static moment M" shall be distributed as foHows: ·...
_---,.
(t)
(2) Slabs
413.7.1.7 Moment redistribution as permitted by Section 408.5 shall not be applied for slab systems designed by the Direct Design Method. See Section 413.7.7. 413.7.1.8 Variations from the limitations of Section 413.7.1 shall be permitted if demonstrated by analysis as long as requirements of Section 413.6. J arc satisfied.
0.65
Exterior Edge
Negfl!ive
factored
~-
-r(4)-
with
Beams between
I3c~l.It1s
Interior SllP[X)rts
between All
--""'(5)
Slab without
Without Edge
&lge
_ _~ar~~
Beams
----_...
0.75
0.70
0.70
0.70
0.65
0.63
0.57
0.52
0.50
0.35
0
0.16
0.26
0.30
0.65
..--.----
With
Exterior Edge Fully
Supp\)n~
Unrcs(r~incd
.."._--" -.. Interior
(3)
Restrained
moment Posi!iv~
factored Moment Exterior
413.7.2 Total Factored Static Moment for a Span 413.7.2.1 Total factored static moment for a span shall be determined in a strip bounded laterally by centerline of panel on each side of centerline or supports. 413.7.2.2 Absolute sum of positive and average negative f~lctored moments in each direction shall not be less than
M"
I I ' .~~
(413-4)
8
where II! is length of clear span in direction that momcnts arc being determined. 413.7.2.3 Where the transverse span of panels on either side of the centerline of SllPpO!1s varies, 12 in Eq. 413-4 shall be taken as the average of adjacent transverse spans.
negative
factored
413.7.3.4 Negative ll10ment sections shall be designed \0 resist the larger of the two interior negative factored moments determined for spans framing into a common suppor1 unless all analysis is made to distribute the unbalanced moment in accordance with stiffness of adjoining elements. 413.7.3.5 Edge beams or edges of slab shall be proportioned to resist in torsion their share of exterior negative factored moments. 413.7.3.6 The gravity load Illoment to be transferred between slab and edge coluilln in aCl:crdancc with Section 413.6.1.1 shall be (UM".
413.7.2.4 When the span adjacent and parallel to an edge is being considered, the distance from edge 10 panel centerline shall be substiwted for /2 in Eq. 413-4. 413.7.2.5 Clear span (II shall extend from face to face of columns, capitals, brackets or walls. Value of II! used in Eq. 413-4 shall not be less than 0.651,. Circular or regular
I
N8!1onal Structural Cocl(:; of tile PlliJipplncs G!' E:dllion Voluille 1
4 ·84
CHAPTER -I. Concrete
413.7.4.5 For slabs wi th beams between supports. ihe slab portion of col umn slrips shall be prop0l1ioncd to re~is ( that portion of column st rip moments no t resi sted by beams.
413.7.4 Factored Moments in Column Strips 413.7.4.1 Column strips shall be proponioncd 10 resist the following percentage of interior negati ve raclOred l11oments: I, l l ,
0.5
1.0
2.0
0
75
75
75
(a",,'!,)1 1.0
90
75
45
~
(a,I,!I,)
Linear interpolations shall be made between va lues s hown. 4 13.7.4.2 Colull1n strips shall be proportioned to res ist th e follow ing percen tage of ex.tenor negative factored moments: I,ll, (a,/,II,)
~
0.5
1.0
2.0
p,~o
lao
100
100
(f,,, 2.5
75
75
75
100
100
100
90
75
45
0 (f,
(a,/,II,)/ 1.0
~
0
/f,:> 2.5
Linear interpolations shal l be made between values shown, where p, is calc ul ated ill Eq . 413·5 and C is calc ula ted in Eq.413·6.
£"C
f3'~2E.1 "
The constant C or T or L-scctions shall be pClmiltco to be cva)u:ucd by dividing the secti on into separate recta ngu lar ;'IS
41 3.7.5. 1 Beams between SUPI}()11s shall be proportioncd to resist 85 perccn( of column stri p momen ts if (all l lil is equal to or ~reate r than 1.0.
413.7.5.2 For values o f (a,l ,II,) between 1.0 and zero, proportion of column strip momellts resisted by beams sha ll be obtained by linear interpo lation belwcen 85 and zero percent. 4 13.7.5.3 In additi on to moments calculated for uniform loads according to Sections 413 .7.2.2. 413.7 .1.1 and 413.7 .5.2, beams shall be proportioned 10 res ist "lI mo mellls ca used by concentrated or linea r loads applied directly to beams, including weight of proj ec ting beam stem above or below the slab. 413.7.6 Factored MOlll en ts in Middl e St ri ps 4 13.7.6.1 T hat portion of nega tiv e nnd pos iti ve factored moments not resi sted by column strips ~hall be proponionately assigncd 10 correspo nd in g half midd le strips.
(413·5)
.
(4 13·6)
parts.
413.7.5 Facto r ed Moments ill Beams
defined in Secti on 413.3.4. and .!\umming the val ues
4 13 .7 .6.2 Each middle strip shall be proportioned to resist the sum of th e momcnts assigned to its two hal f mi ddle strips. 4 13.7.6.3 A middle strip adjace nt lO and p_mllid \'!iIh an edge supported by a wall shall be proportioneo ttl l (:s-is{ twicc the moment assigned to the half lllitJdk :.Irip corresponding to the first row of intcrior supports.
of C for each part. 413.7.4.3 Where suppon s consist of column s lor walls extending for a di stance equal to or greater th an three fourths Ihe span lengt h I} lIsed (0 compu te M ,,, negativc momcn ts shall be considered to be uni formly distributed across f} . 4 13.7.4.4 Column strips shall be proportioned to res ist the fo ll owing perccillage o f positive factored IllOrnCI1IS:
1,1 /,
--_._-(u,/,II, )
~
0
(0, 1,11,)1 1.0
0.5 --'-
- -
1.0 '- '---'-
60
60
90
75
2.0
_._ - --
..---------- ~----- -
(i()
45
- -- -
41 3 .7.7 Modifi ca ti on of Factored MO lll ents Modification of negative and pos iti ve factored 1l10Jll('I! !.o,; hy I () percent shall be permitted provided ·( he I (:! :ll . ,. !il" moment for a panel in the direc ti o n th an that required by Eq . 4 13·4.
COIlS ilL:l d
;" ;:.:. ), .':.
413.7.8 Factored Shear in S lab Sys tems wi th Beams 413.7 .8. 1 Beams with a,tzlt, eq ual to or grf'.' Ir.r Ilwn J.n shall be propo rtioned to resist s hear cau!\cd 1 , ~. r;\f'[·':'- : loads on (ributitry areits hound ed by 45-degn.·.c Ii!!,: ::; .!J.: from the corners of the panels and the cc nlf''' !inf's of fh:-: Hdjaccnt panels parallcl to (he lo ng s ides.
Linear inlerpolations shall be made between values shown : !\ssocin ti on of S tru Clu((1 1Engineers of the Ph ilippine s
I
CHAPTE f1 4 . Concrele
, !
413.7.8.2 In proportioning of beams with a//]II, less th an
1.0 to resist sheaf, linear interpolation, ass uming bea ms carry 110 load at a,::; O. shall be permitted . 413.7.8.3 111 addition to shears calculated according to Sections 413.7.8. 1 and 41 3.7.8.2, beams shall be propol1iol1cd to resist s hears caused by factored lo'lds
applied directly on beams. 4]3.7.8.4 Computations of slab shear slrcngih o n the
ass umption that load is distributed
(0
supportin g beams
413.7.8.5 Shear strength shall satisfy requirements of Section 4 I I. 413.7.9 Factored MOlllents in Columns and Walls
413.7.9.1 Colum ns and wa lls built integrally with a slab system shall resist moments caused by factored loads on the s lab system.
413.7.9.2 At an interior support, supporting clements above and below the s lab shall resist the ractored moment specified by Eq. 413·7 ill direct proportion to their stiffncsscs unless a general analysis is made.
(I ',,)'J
413.8.2.2 Each frame shall consist of a row or columns or su pports and slab·beam strips. bounded laterally by the centerline of panel on each side of the centerline or columns or supports. 413.8.2.3 Columns or su pports shall be assumed to be aU
. 1\
accordance with Section 413.7 .8. 1 or 4 13.7.8.2 shall be permitted. Resistan ce to lOtal shea r occurring on a panel shall he provided .
M = 0 .07 [('I,,,, + 0 .5 q",) I, I,,' - q '".1',
4·85
(4 13· 7)
413.8.2.4 Frames adjacent ano parallel 10 an edge shall be
bounded by that edge and the ce nt erline of adjaccnt panel. 413.8.2.5 Analys is or each equiv.alenl frame in its entirety shall be pennitted. Alternatively, for gravit y loading. a separate anal ysis of each floor or roof wit h far ends of columns considered fixed shall be permi tted. 413.8.2.6 Where slab· beams are analyzed separatel y, determinmion of moment at a given support assuming (hat the slab·beam is fixed at any su pport two panels distant therefro m, shall be permilted provided the slab continues beyond that point. 413.8.3 Slab-Belll"s
413.8.3.1 Determination of [he moment or inertia of slabbeams :11 any cross section oUlside of jOints or column capitals using the gross Mca of conc rete shal l be pennittec1.
where q'd. /'2 and /'" refer to shorter span . 413.8 E(Juivalenl li"rame Method 413.8.1 Design of slab systems by the equi val ent frame method shall be b,lsed on assumpti ons given ill Secti ons 4 13.8.2 through 4 I 3.8.6 and all seelions or slabs and
suppo rt ing members shall be proportioned for moments and shears thus obtained.
413.8.3.2 Varia ti on in moment of inerti a along axis of slab· beams shall be taken into account. 413.8.3.3 Moment of inert ia of slab·hcilms from cClHcr of column to face of column, bra cket or capital shall be assumed equal 10 the moment of inertia of the slab·bea m al face of column. bracket or capilal divided by the quantity {I - ell ])1 where c] and I] .tre measured transve rse to the directi on of the span for whi ch moments arc being determined.
413.8.1.1 Where metal column capitals arc used, it shall be permitted to take account of their contributions to stiffness and resistance to moment and (0 shear.
413.8.4 Columns
413.8.1.2 Ncg lc(; ting Ihe change in le ngth of col umlls and slabs uu e 10 direct stress, .1I1d derl c{, l.io ns due to she.lr, shall be permillcd.
413.8.4.1 Determination of the 1l1 0 lllCIll 01' inerti a of columns ,It any cross section outside of joints or colu mn capitals using the gross area or concrete ~ha ll be perm itted.
413.8.2 E'IUiv"lcnl Frame
413.8.4.2 Variation in 1l10ment of inertia along axis of colu mns shall be taken into account.
413.8.2. I The stl1lclUrc shall be considered 10 be made up of equivalent frames 0 11 colullln lines taken IOll gitudin:lll y nne! transversely through the building.
413.8.4.3 Momcnt of inert ia of columns from top to bottom of th e slab·bea m ;It a joint s hall be ass umed infinite.
1
Nati ona l StrucltJr(11 COd e of li te Philippines 6 1\ Edition Vo lume '1
4·86
CHAPTEI1"· Concre\()
413.8.5 Torsional Members 413.8.5.1 Torsional members (,sec Section 413.8.2.3) shall be assumed [0 have a constant cross section throughout their length consisting of the larges! or:
J.
A portion of slab having a width equal to that of the column, bracket or capital in the direction of the span for which moments arc being determined; or
2.
F'OI" !llonolithic or fully composite constmclion, the portion of slab specified in (J) above plus that part of the transverse beam above and below the slab; and
3.
The transverse beam as defined in Section 4! 3.3.4.
413.8.5.2 Where beams frame into columns in the direction of the span for which moments arc being determined, the torsional stiffness shall be multiplied by the ratio of moment of inertia of slab with sllch beam to moment of inertia of slab without such beam.
from face of supporting element not greater than one-half the projection of bracket or capital beyond face of supP0l1ing element. 413.8.7.3 Circular or regular polygon-shaped supports shall be treated as square supports with the same area for location of critical section for negative design moment. 413.8.7.4 When slab systems within limitations of Secti{)11 413.7.1 are analyzed by the Equivalent Frame Method, il shall be permitted to reduce· the resulting computed moments in such propol1ion that the absolute sum of the positive and average negative moments used in the design need not exceed the value obtained from Eq. 413-4. 413.8.7.5 Distribution of moments at critical sections across the slab-beam strip of each frame to column strips, beams and middle strips as provided in Sections 413.7.4, 413.7.5 and 413.7.6 shall be permitted if the requirement of Section 413.7.1.6 is satisfied.
413.8.6 Arrangement of Live Load 413.8.6.1 When loading pattern is known, the equivalent frame shall be analyzed for that load. 413.8.6.2 When live load is variable but does not exceed three~fOt1J1hs of the dead load, or the nature of live load is such that all panels wil! be loaded simultaneously, it shall be permitted to assume that maximum factored moments occur at all sections with full factored live load on entire slab systelll. 413.8.6.3 For loading conditions other than those defined in Section 413.8.6.2, it shall be permitted to assume that maximum positive factored moment ncar midspan of a panel occurs with three-fourths of the full factored live load 011 the panel and on alternate panels; and it shall be permitted to assume that maximum negative factored moment in the slab at a support occurs with three-rOll!ills of the full live load on adjacent panels only. 413.8.6.4 Factored moments shall not be taken less than those occurring with full factored live load on all panels. 413.8.7 Factored Moments 413.8.7.1 At interior supports, critical section for negative factorcd moment in both column and middle strips shal! be takcn at face of rectilinear supports, but nol greater than O.17.')f! from ccnter of a columll. 413.8.7.2 At exterior supports provided with brackcts or capitals, critical section for negative factored moment in the span perpendicular to an edge shall be taken at a distance
Association of Structural Enguieers of tile Philippines
CHAPTER
Ph PI
= gross area of section, 111m2 :::;: area of longitudinal tension rei nforcement in wall
2 segment, Illm = area of effective longitudinal (ension reinforcement
Au
. Concrete
4·87
;:::
reinforcement ratio producing balanced strain conditions ;::: minimum ratio of vertical reinforcement area to gross concrete area
414.2 Scope
414.1 Nolalions AI-' At
~
2
or
414.2.1 Provisions Section 414 shall apply for design of walls subjected to ax ial load, with or without fl exure. 414.2.2 Cantilever reta inin g walls are des~gned according to flexural design provisions or Section 410 with minimum horizontal reinforccmcnt accordi ng to Sect ion 414 .4 .3.
f't'
in wall segment, mm as calcul ated by Eq. 414-8 = distance from extreme compression fiber 10 ne utral axis , mOl :::;: distance of extreme compression fiber to centroid of longitudinal tension reinforcement, 111m = modulus of elasticity of co ncrete. MPa ;: ; specified compressive strength of concrete, MPa
414.3.1 Walls shall be designed for eccentric loads and any
J;.
= specified
lateral or olher loads to which they are subjected.
c d
Ec
yield strength reinforcement, MPa
of
nonprestresscd
= QveraJlthickncss of member. mm
II fa
;::: moment of inertia of cracked section transformed 10 concrete, 1111114
Ir
;:: effective moment of inenia for co mputation of
k
::::: effective length factor
deflecti on.
1111n4
I,.
;::: vcrtical distance betwcen supports, mm
/". M
M"
= honzollwl length of wall , rn III = maximum unfactored moment due to service loads, including PA effects ;::: max imum l110 melll in member at stage deOeclion is
Mrr
;::: moment cau!> in g nexural crack in g due
compUl cd
..1"
to applied lateral and vertical loads = no min al moment strength ttl sec ti on ::::: ma ximulll unfactored applied momcnt d ue to service loads, not including PA effec ts ::: factored mOIllCIlI at section including PA effects ;::: moment al the mid hcight secti on of the wall due to factored lateral and eccentric vertical loads ::: modular ratio of elasticity, but nOl.l ess than 6 ~ E/E, ;::: nominal axiiIl load strength of wall designed by Section 414.5 = unf"aclored axia l load at (he desig n (midhcigilt) sect ion incl ueling effccts o f sclr-wcigtll = factored axial load = maximum deflection at or flear Illidhc ight due to service loads, I11Ill = denc.ctioll at midheighl of wall due to fHclmed
¢ p
loads, mill :::. strcllgtlH'cd uctioll factor. Sec Sec ti o n 409.4 ;::: mtio of te ns io n re inforcement
M" M ",
Mu M"fI II
P" P,
Pt , .d..
~
A /(I"d)
414.3 General
414.3.2 Walls subject to axia l loads shall be des igned ill accordance with Sections 4 14.3, 414.4 and e it her Sections 414.5,414.6 or 414.9. 414.3.3 Design for shear shall be in accordan ce with Section 411.11. 414.3.4 Unless demonstrated by a de tail ed analysis, horizontal length of wall to be considered as effective for each concentrated load sh
414.3.6 Walls shall be flllchored to intersect ing elements such as 1100rs or roofs; or 10 co lumns. pilasters. buttresses, and intersecting walls; and to footings. 414.3.7 Quantity of" reinforcement ancl limits of thickness required by Sections 414.4 an d 414.6 shall be pe rmitted to be waived where structural ana lysis shows adequate strength and stabi lity. 414.3.8 Transfer of force to fOOling at base of wall shall be in accordance wi:h Section 4 15.9 . 414.4 Minimum Reinforce ment 4J4.4.1 Minimum vertical and horizontal reinforcement shall he in accordance wit h Sections 414.4 .2 ,lIld 414.4.3 unless a greater ;1I110Ullt is required for shear by Sectiolls ~11 . 11.8 <111<1411.11.9.
Nelliona! Slructur(ll Code of ti""H: PI'ilippill(~s G E:cJition VolumH 1 lh
4-88
C H APTEI~
4 . Concreto
414.4.2 Minimum ratio of ve rti cal reinforcement area
10
gross concrete area, /1" shall be: L
0 .0012 for deformed bars 11 0 1 larger than rn l6 mill with spcci (jed yield strength not less than 4 15 MP,l; or
:I
2.
3.
0 .00 15 for other deformed bal's; or
414.5 Walls Design as Co mpression Members Except as provided in Secl ion 414.6, walls subject 10 nxi.aJ load or combined flex ure and axial load shaH be designc'; as compression members in accordance with provisions of Seclions 410.3, 410.4 , 410. 11, 410. 15. 410. 18, 4 14 .3 nnll 414.4 .
0.0012 for welded wire reinforcement (plain or deform ed) nOt larger than MW 200 or MD200
414.6 Empirical Design Method
414.4.3 Minimum ratio of horizontal reinforcement arc.1 10 gross concrete arc, P" shall be: I.
0.0020 for deformed bars not larger than 16 mill d i:l mcter with a specified yield streng th 110 1 less (han 415MPa;or
2.
0.002S for oth er defo rmed bars ; o r
J.
0.0020 for welded wire reinforcement (p lai n or deformed) not larger than MW 200 o r MD200.
414.6.1 Walls of solid rectangular cross section shaH he permitted to be designed by the empirical provisions of Seclion 414.6 if resultant of all factored load s is localed within the middle third o f the overall thickness o f wa ll and . 11 limits of Sections 41 4.3, 414.4 and 4 14 .6 are salis fled. 414.6.2 Design axial strength ¢P, of a wall satisfyi ng limitations of Section 414.6. 1 shall be com pUled by Liq . 414-1 unless designed in i.lccordance with Section 414.5.
¢,P,
414.4.4 Wall s morc than 250 111m th ick, except basement
walls, shall have reinforcement for eac h di rection placed in two layers parallel with faces of wall in accordance with the following: 1.
2.
One la yer co nsisting of not less than one half and not more than two-thirds of total reinforce ment required for each direct ion shall be placed not less than 50 mm or more than one-third the thickness of wall from exterior
= o 55¢f'c A,[I-(;~~JJ
(4 14-1)
where ¢ shall correspond to compression~c()ntrolled sections ill accordance with Sect ion 409.4.2.2 and effectivc length faclol' k shall be: For walls braced lOp and bo ttom against lat eral translati on
surface.
and
The ol her layer. co nsisting of the balance of required
I.
reinforcemen t in that directi on. s hall be placed not less than 20 I11Ill o r more than one-third the thickn ess o f
2.
Res trained against rotarian at one Or both ends (top, bOllom. or bOlh) .. . ....... Un restra ined against rotation at both ends
0.8
1.0
wall from imcrior surface . For walls not braced against lalcrallranslali on
414.4.5 Vertical and hori zontal reinforceme nt shall not be spaced farther '.P
414.4.6 Vertical reinforcement need not be enclosed by lateral tie~ ir vClikal reinforcement area is not greater than 0.0 I times gross conc rete area. or where veliical reinforc eme nt is not req uired as com prcssion re inforcemcl1t. 414.3.7 In additioll 10 the mini mum rein forcement requi red hy Sectioll 4 14.4. 1. nOI less than two 1?l 1<1 111111 bars in walls hav ing I Wo JaYl'rs o r rein forceme nt in hOlh directi o ll s ilnd nnc J?Jl(1 111111 har 111 wa ll s having a single la yer of 1\.'inforn.'Illl'lll ill both direction shall he provided around window, uoor. and similar s iz.ed o penings. S tich bars shilll be ilndlOretl 10 develo p .r;. in {e ll sio n at the cnrncrs or the open ings.
!\%OC i,l tIClfl of Structural
2.0
414.6.3 Minimum Thickness of W"Us Des igned by Empirical Design Method 414.6.3.1 Thickness of bearing walls shall not be less thnn I!2S the supported heigh t or length, whi chever i~; :;1\01( nor less than 100 mill .
or
414.6.3.2 Thi ckness ex terior ba:-;clllcnl walls ;'. founda ti o ll walls s hall not he less than 190 Illill . 414.7 Non-Bearing \Alalls
or
414.7.1 Thickncs!-i lion hearing walls sha ll 1101 hI' k ~: ·. I l!," ~ 100 mill. or lIot less tllilll II~O the IC;I~t di ~.I: III ' ·· f .' members thai provi de 1;ltcral support.
En9111ecns of tile
PtliliP PU10S
CHAPTEn 4 . Concrete
where:
414.8 Walls as Grade Hearns
(414·4)
414.8.1 Walls designed as grade beams shall have top and boltom
reinforcemclll as required for moment in accordance
with provisions of Sections 410.3 through 410.8. Design for shear shall be in accordance with provisions of Section 411 .
M"llJ is Ihe maximum factored moment at the midheight sect ion of Ihe wall due (0 lateral and eccentric venical loads , not including Pd effects and L1.. is:
414.8.2 Portiol1~ o[ grade beilm walls exposed above grade shal l also meet rcqlJircmcl1ls of Section 4 14 .4. 414.9 Alternate Design of Slend er Walls
414.9.1 When nCltural tension controls the out-or-plane design of a wall. th e requiremenls of Section 414.9 arc conside red (0 satisfy Seclion 4 10.1 L . 414.9.2 Walls designed by the pro visions of Section 414.9 shall satisfy Sections 4 14.9.2. I ihrough 4 14.9.2.6. 414.9.2. 1 The wa ll panel shall be designed as a simply suppol1cd. axi;lll y loaded me mber su bjected to an out-of· planc uniform later;11 load, with maximulll moments and deflec tions occurring at midspan.
5M 1 2
=
/j,
,
414.9.2.2
4·89
lie
(414-5)
(0.75)48£,1"
Mil shall be ohlaincd by iteration of denections, or by direct calculati on using Eq. 414-6.
(414·6)
where: = E, (A
I"
E.
."
+ P)l . (d -c )' + I .. c" f,.2d 3
(4 14·7)
and the value of E/l:.~, shalinOl be takcn less 111M 6.
The <.: ros s section shall be constant over the
height of th e panel.
414.8.4 The maximum dcncctiOIl 4,. due to service loads. including P6 effects. shilllnol exceed 1,.1150.
The wall shall be tension-comrollcu.
(414 -2)
If Mf ,. maximum moment al midhcight of wal l due to service loads. includi ng PLI effects, exceeds (2J3) M •." £1 , sh.1I be calc ulated by Ell . 414 -8
wherc "'-I.. sha ll be oblilincd using the modulus (If fupture, };" give n by 1:(1 . 40l)-t).
LI =2136 !!1,,-2 ~~ M"){6 -21J6 ) (4 14-8) • " ( M .-2IJM .. ' ..
414.9.2.5 Concentrated gravi ty loads applied 10 Ihe wall above the design ncxural section shall be assumed to be distributed over a width:
If M" docs not exceed (2I3) M .... 6 , shall be calculated by Eq.414-IO
414.9.2.4
I.
Rcinforccmcill
sh~IJI
provide a dcsign strength
Eqllallo the bearing width, pillS (1 width all each side that increases at a slope of 2 vertical 10 I horizontal
(414-9)
where:
down to the dcsign sec tion; but 2.
Not gre.Hcr Ilwn the spacing of the concclllrmcd loads: and
3.
Docs not extcnd beyond the edges of the wall pancl.
414.9.2.6 Venical stresses P,/A g at the midhcighl section shall nnt exceed O.O(y·...
r,l/
(414·10)
'" = 5M), ~_ " 48£•.1..,
(414-11)
I!'J
"
= 5M 48 E , 1,
I,.r sll
414.9.3 The design moment strengt h (k\1" fOf ro mhincd fl ex ure and a:dal loads at the midhcighl s hall he (4 14-3)
Nn!IOrl r.l l StlllctlJrnl Code of ti lO P ililippinw;
(jIl l
E:dition VOllll'lle '1
4·90
CHAPTER
~
. Concre te
,"'-.; -',.:.
415.5.2 Maximum factored moment for 'an isolated footing shall be computcd as prescribed in Sec ti on 4 15.4.1 al critical seclions located as follows:
'"
-."/- S·.,· ., ......
.;
• • . ,R, • '. "
."
I,
AI f(lce of colum n, pedestal , or wall, for footings suppol1ing a concrete column, pedestal, or wall ;
415.1 Notations A,t'
= gross area of section, mm
(/"
P
: ;.
2. 2
diameter of pile. il l footing base, mm ralio of long side to shon side of footin g
3.
Halrway between middle ami edge of wall, for footings suppo rting a maso nry wall; Halfway bet wee n facc of column all(; .edge of steel base pl'HC, for footi ngs suppo l1 ing a col ldlHl with steel base
pl:.uc. 415.2S
415.2.1 Provisions or Section 415 shall 'Ippl y for des ign of isolmcd fOOlings and. where applicable. to combined
415.5.3 In one-way footings and two-way squarc foolin?.:; , reinforcement shall be disltibu(cd unifonnly across entire widt h of fooling.
foot ings and nwls. 415.2.2 Addit ional requirements for design of co mbined
415.5.4 In l WO-WHY rectangu lar footi ngs, reinforcement shall be distributed as follows :
foo tings and Illats are gi veil in Section 4/5.11. 415.5.4.1 Reinforceme nt in lon g direction shall di stributed uniforml y across cmire width of footing.
415.3 Loads and Reactions 415.3.1 Footin gs shall be proportioned to resist th e factored loads and induced reactions, in accordan ce wit h the appropriate design req uiremen ts of this code and as provided in thi s section. 415.3.2 Base area of foot ing or !lumber
be
415.5.4.2 For reinforcement in short direction, a portion of the total reinforcement y,A, given by Eq . 415-1 shall be distributed uniformly over a band width (centered on centerline of column o r pedeslrI l) equal to the length of sll' dt side of footing. Remainder of reinforcement requi red in short direction , ( I - )',)A" shall be distributed uniform ly outside center band width of foo ting.
Rcillforccmem in " A ," __l_,a_"_d_w_id_t_h_
TOlal ReinforcemclII in short direction
2
(415- 1)
(ji+ I )
where Pis ratio of long to short sides of fOOling.
415.4 Footings Su pporti ng Circul ar or Rcgulur Polygo nShap ed Colu mn s or Pedcs tal s
415.6 Shear in Foo tin gs
Fo r locati on of cri tical sections for moment, shear
41 5.6.1 Shear strength in footings shall be in accn nl ance with Section 4 11.1] .
:;amc arCi!.
415.5 Moment in Footings
415.6.2 Locali on of crilical sec tion for shear in 'Ic{:{ml :!'ce wi th Section 41 1 sh.a ll be measured from face or (:ok!lJ lI. pedesta l or wall, for footings support in g a co lumn , pedestal Of wall. ro r foo lings suppon ing a colullln or pedestal wilh steel base pl
4]5.5.1 EX lerna l moment o n an y seclio n of a foo ting shall
be determined by passing a vertical planc through the (oming and com puti ng the moment of the rorces acting over the cn ti re ;lfca of fo()( ing o n olle ~ idc of tl1 ,11 vertical JlI;Jnl~.
/l..$so cintlon of Stru ctll r111
4J5.6.3 Where the disla nce hctwecll the axis of an y p;~'~ to the axis of the column is Jllore th an t WO times the di~wl1ce between the to p or th e pile ca p and til e top of !Il(' pi!; , {ile pile cap shall sati sfy Sections 4 11 , 13
E n911"lC:CJS
of Ihn Phili ppines
CHAPTEfl 4 - Concrete
411.13 and 415.6.4. If Section 427 is used, the effective concrete compression strength of the struts, fw shall be determined using Section 427.3.2.2, Item 2.
4-91
bearing strength for either surface as given by Section 410.18. 415.9.1.2 Reinforcement, dowels, or mechanical connectors
415.6.4 Computation of shear on any section through a footing supported on piles shall be in accordance with
between supported and supporting members shall be adequate (0 transfer:
Sections 415.6.4.1,415.6.4.2, and 415.6.4.3:
I.
415.6.4.1 Entire re~iction from any pile whose center is located dl'i/J2 or' 'more' outside the section shall be considered as producing shear on that section.
All compressive force that exceeds concrete bearing strength of either member; and
2.
Any computed tensile force across interface.
415.6.4.2 Reaction from any pile whose center is located dpil )2 or more inside the section shall be considered as
producing no shear in that section. 415.6.4.3 For intennediate positions of pile center, the portion of the pi Ie reaction to be considered (IS producing
shear on the section shall be based 011 straight-line interpolation between full value at dp ",.12 outside the section and zero value at dpi /,J2 inside the section. 415.7 Development of Reinforcement in F()otings 415.7.1 Development of reinforcement in footings shall be in accordance with Section 412.
In addition, reinforcement, dowels or mechanical connectors shaH satisfy Section 415.9.2 or 415.9.3. 415.9.1.3 If calculated moments are transferred to supporting pedestal or footing, reinforcement, dowels or mechanical connectors shall be adequate to satisfy Section 412.18. 415.9.1.4 Lateral forces shall be transferred to supporting
pedestal or footing in accordance with shear-friction provisions of Section 411.8 or by other appropriate means.
In cast-in-place construction, reinforcement required to satisfy Section 415.9.1 shall be provided either by extending longitudinal bars into supporting pedestal or footing, or by dowels. 415.9.2
415.7.2 Calculated tellsion or compre~sion in reinforcement at each section shaH be developed on each Side of that section by embedment length, hook tension only or mechanical device, or combinations thereof.
415_9.2.1 For cast-in-place columns and pedestals, area of reinforcement across interface shail not be less than O.005A g , where Ag is the gross area of SUppo!1cd member.
415.7.3 Critical sections for development of reinforcement
415.9.2.2 For cast-in-place walls, area of reinforcement across interface shall not be less than minimum vertical reinforcement given in Section 414.4.2.
shall be assullled at the sallle locations as defined III Section
415.5.2 for maximum factored moment, and at all other
vertical pJanes where changes of section or reinforcement occur. See also Section 412.11.6. 415.8 Minimum Footing Depth
Depth of footing above bottom reinforcement shall not be less than 150 mill for footings on soil, or not less than 300 mm for footings on piles. 415.9 Transfer of Forc{~ at Base of Column, \Vall or Reinforcement Pedestal 415.9.1 Forces and moments at base of column, wall, ill'
pedestal shall be transferred to supporting pedestal or footing by bearing on concrete and by reinforcement, dowels, and mechanical connectors. 415.9.1.1 Bearing 011 concrete at contact surface between supported and supporting l11ember shall not exceed concrete
415.9.2.3 At footings, fM2 n1ln and [1J58 mill longitudinal
bars, in compression only, may be lap spliced with dowels to provide reinforcement required to satisfy Section 415.9.1. Dowels shall not be larger than [1]32 mm bar and shall extend into supported member a distance not less than the larger of ide> of fil42 mOl or ru58 mm bars or the splice length of the dowels, whichever is greater, and into the footing a distance not less than the development length, ide of the dowels. 415.9.2.4 If a pinned or rocker connection is provided in cas.-in-place construction, connection shall conform to Sections 415.9.1 and 415.9.3. 415.9.3 In precast construction, anchor bolts or suitable
mechanical connectors shall be permitted for satisfying Section 4! 5.9.1. Anchor bolts shall be designed in accordance with Scclion 42~.
Nnlionili Structural Code of tl'1(-; Philippines Gill Edition Volume 1
4 ·92
CHAPTER 4 . Concrete
415.9.3.1 Connection between precast columns Or pedestals
und supporting members shall meel Ihe rcquircmcnls of Section 416.6.1.3 , Item I.
415;9.3.2 Connection between precast walls iJnd supporting members shall meet the rcquircIllcllts of Scclioll 4 16.6. 1.3, It ems 2 and 3.
416.1 Notations
415.9.3.3 Anchor bolts and mechanic
I
A, failure or failure of surro unding concrete. Anchor bohs shall he designed in accordance with Section 423. 415.10 Sloped or Stepped Footings 415.10.1 In sloped or stepped footings, angle of slope or depth and location of steps shall be such Ihal design rcquircmcnls arc satislicd al every section. (Sec also Section 412.11.6). 415.10.2 Sloped or stepped footings designed be constructcd to ensu re action
(I S
n unit
ShOll!
415.11 Combined Footings and Mats
415.11.1 Footings supponi ng Illore thall aile column. pedestal. or wall (combincd footings or mil ts) sha ll be propol1ioned to resist the factored loads and induced reactions, in accordance with appropriate design rcquirements of lIlis codc.
415.11.2 The Direct Des ign Method of Section 411 shall 1101 be used for design of cOlllbincd footings and milts. 415.11.3 Distribution of soi l pres!'>urc ti nder t:o mhilled footings and mats shall be consistel1t with properties of the soil and the structure
415.11.4 Minimum reinforcing steel illllonprcstrcsseu llIilt foundations shall meet the requirements or Sectioll 407. 13.2 ill each principill directi oll. Mt.lximull1 sp.tdng shall 1I0t exceed 450 mill. 415.121)lai:o Concrete Pedestals and
F ()O lill ~s
gross arC'l of column, mill = clear span, n1l11
416.2 Sco pe
416.2. 1 All provisi ons 01" this code not speei ricall y I~ .~·.l :rd,",! and not in conniet with the pro visions of Section .11(1 . ..;k-'! apply to structures incorporating precast concrete :-.liU..:lUHii mel1l bers. 416.3 Gene ral
416.3. 1 Design of prectlst members and connections shall include loading (ltld rcslraim conditio ns from initi ,,1 fabri cat ion to end use in the Slrucrure, including fo rm rcm ovill , storage. Inlnsportatioll lind erection.
416 .3.2 When precast members are incorpol'fur.d ill!o a struc tural sys tem. the forces and deformations {lI., ·ui J"i lifl i!l ;lnd adjace nt 10 cOllnections shall be included in Iht dcsign. 4 J6.3.3 Tolcr'lIlccs for both precast mcmbl'r~ and illlcrf
Details of reillf"orcc mcm, inserts and lifting devices required to resist lemporary loads from handline. stor~lge . Iransport .llion and erection;
1.
Required conc rele strc ngth at st.lle.d ages or consl nlctiOiI.
~1;If!es
of
4 J 6.4 Dis tribllti on 01' Forces among MClllhcrs
Sec Section 422. 4 16.4. 1 Distributioll of forl:ts Ihm arc pl~ rpcndicul;\r 10 Ih e. pi ail e or rlll'.Jl1hcrs shall he c...;tahli shcd by
10
wall sys tem . the 1()llowing :-.l1all appl y:
CHAPTER 4 . Concrete
416.4.2. 1 In-plane force paths shall be continu Dus through
2.
Precast wall panels shall have a minimum of two ties per panel, wit h a nomi nal tensile strength not less than 44 kN per tic ;
3.
When design forces result ill no tension at th e base, the lies requ ired by Sec tio n 416.6.1.3. Ite111 2. shall be pcrmi ll ed 10 be anchored illlo an approp ri ate ly rein forced concrete noor slab 011 grade.
Doth connections and members.
4J6.4.2.2 Where tension forces occur, a cont inuous paLh of slcel or steel reinforcement shall be provided. 416.5 Member Design 416.5.1 In one-way precast /1001' an d roof' slabs and in oncway precast, prestressed wall panels, all no! wider than 3.7 Ill, and where members arc ' not mec hani cally co nnected 10 cause restraint ill the transverse di recti on, the sh rinkage and tempcrcuure reinforce ment requirement s o f Section 407 . 13 in the direct io n normal to the flexural reinforce ll1elll shall be pcnni ued 10 be waived. This waiver shall not apply to members which require reinforcement to resist transverse fle xural stresses. 416.5.2 For precast. nonpreslrcssed wall s the reinforcement shall be designed in accorda nce wilh the provisions of Sections 410 or414 . exce pt that the area horizontal and vert ical reinforcem ent 511<111 eac h be not less than O.OO IA!:, where Ag is the gross cross-sec tional area o f the wall panel. Spacing of reinforce men t shall not exceed 5 limes the wall thickness nOr 750 111m for interior wall s or 450 mm for ex terior wall s.
or
416.6 Structural 1ntegrity 416.6.1 Except where the provis ions of Sc<.:tion 416.6.2 govern, the minimum provisions of Sections 4 16.6. 1.1 through 4 16.6.1.4 for slru clUrai integrity shall app ly to al l precast cO ll crete struc tures:
41 6.6. 1.1 Longitudinal and transverse li es required by Seclion 407. 14 .3 shall connect members 10 a latera l load resistin g system. 416.6.1.2 Where precast elements form floor or roof
4·93
416.6.1.4 Connection details that rely solely on friction ca used by gravilY loads sha ll nOI be used. 416.6.2 Por precasi··concrete bearing wall structures three or more stori es in height, the following minimum provisions shall apply: 416.6.2.1 Longitud inal and tran sversc lies shall bc provided in floor and roof sys tems to provide a nominal strength of 22 kN/m of widlh or lenglh. Tics shall be provided ove r interior wall supports and between members and exterior walls. Tics shall be positi oned in or within 600 mm of the plane of the fl oor or roof systcm. 416.6.2.2 Longitudinal lies parallcl 10 floor or roof s lab spans shall be spaced not more Ihan 3 m on ce nters. Provisions shall be made to transfer forces around openings. 416.6.2.3 Transverse ti es perpendicular to floor or roof sl ab spans shall be spaced not greater than the bealing wall spaci ng. 416.6.2.4 Ties around the perimeter of each Ooor and roof, wi thin 1.2 III of the edge, shall prov ide a nominal strength in tension nOllcss Ih an 70 kN . 416.6.2.5 Vcn ical tens io n lies s hall be provided in all walls and shall be continuous over thc height o f the bu ildin g. They sha ll prov ide a nominal tensi le stren gth not less than 44 kN per horizontal meIer of wa ll. Not less than two lies shall be provided fo r cilch precasl pallci. 416.7 Connection and Bearing Design
diaphragms, the connections between diaphragm and those members being laterall y suppol1ed shall have a nominal tens ile strength capable of resisting not less than 4.4 kN/m.
416.7.1 Forces sha1l be permitted to be tran sferred between members by grouted joints, shear keys, mechanical COll nectors, reinforcing stee l co nnections, reinfo rced topping or a co mbination of these means .
416.6.1.3 Ve rti c:!! tension tic req ui re ments o f Section 407. 14.3 shall appl y 10 all ve ni cal struchl r;ll mc mbcrs, ('xeepl cladding, ill UJ slwll be ac hi eved by prov id ing co~, nccliol1 s .11 horiz.ontal joints in
416.7.1.1 The adequacy of connectio ns to transfer forces between members shall he detennined by analysis or by Lest. Where shear is Ihe primary res ult of imposed loading. it sha ll be permiHed to lise the pro vis io ns o f Sect ion 41 1.8 as applicable.
I.
Precast
nllul1lllS
s hall have
i!
nornimd strength in 416.7.1.2 When designing;! co nnection using materials with
tension nol less than I.4Ag , in N. For columns with a larger cross sec tion tha n required by cOlIsiiJer:llioll of
different structura l properties. their relali vc st iffnesscs,
loading.
st rength s and ductili ties s hall be co ns idered.
reduced effective area AG • based on (fOSS btll not less Ih an olle-hal f the (olal arc.l. s hall be permitt ed:
seclioll
It
requirl~ d
N~ltiona l Slru c(ufnl Co de or th e PIli iiPPll18S b!1l Edition VOl!lnl O '1
4 ·94
CHAPTER 4· Concrete
416.7.2 Dearing for precast floor and roof members on si mple support s shall satisfy the following : 416.7.2.1 The allowable bearing stress at the cont act surface between supported and slippol1ing members and between any intermediate bearing elements shall not exceed the bearing strength for both su rface .mil the bearing elemen t. Concrete bearin g strength sha ll be: as given in Section
416.9 Marking and Idenlificalion 416.9.1 Each precas t member shall be marked 10 indicate its location tint! ori en tati on ill the sln_cture and date of manufactu re.
410.18.
416.9.2 Ident ification marks shall cOITespond to placing drawings.
416.7.2.2 Unless shown by test or analysis that pcrfonnance will not be impaired, the following minimum requirements shall be met:
416.10 Handling
I.
Each member and its supporting system shall ha ve design dimensions selected so that, after consideration of tolerances, the di stance from the edge of the support to the end o f the precast member in the direction o f the
span is at least 111 80 of the clear span, I, but not less than: For solid or holl ow-core slabs .. For beams or stemmed members ... . 2.
50mm 75 mm
Bearing pads at unarmored edges shall be se t back a
minimum of 13 111m from the face of the support. or at least the chamfer dimension at chamfered edges. 416.7.2.3 The requirements of Secti on 412. 12.1 shall not a pply to the posi tive bending moment reinforcement for s tatically delermi nale precas t members. but at least oncthird of such reinforcemen t shall extend 10 the ccn tcr of the bearing length. 416.8 lIems Embedded After Concr.le Placement 416.8.1 When appro ved by the engi neer, embedded items s uch as dowels or inserts that either protrude from the concrete or rem ai n exposed for inspecli o n shall be permitted to be embedded while the concre te is in a plastic state provided that:
416.10.1 Member design shall cOllsider forces an d di stortion s during cu ring, stripping. storage, transportation and erection so that precast members are not overstressed or otherwise damaged . 416.10~2 Duri ng erection, precast memhcrs and st ructures shall be adequately suppo rted and braced to ensure proper alignment and Slmctural integrit y until pe nnanenl connections are completed.
416.11 Strenglh Evaluation of Precast Conslruction 416.11.1 A precast elemen t to be made compositc wi th c'ls l· in·place concrete shaH be pcrmitted to be tested in fle xure a~, a preenst element alone in accordance with the [oll owing: 416.11.1.1 Test loads shall be applied only whell calculations indicate Ihe isolated precast element will not be critical in compression or buckling. 416.11.1.2 The test load shall be th at load whi ch, when applied to the precast me mber alone. induces Ihe same lol ;,! force in the te nsion rei nforcement as would be induced hy loading the composite mem ber with th e test load required by Section 420.4 .2. 416,11.2 The provisions of Section 420.6 shall be th e basi·; element. rejiwJi on of the
416.8.1.1 Embedded items are not required to be hooked or tied to reinforcement within the concrete. 416.8.1.2 Embedded items are maintained in th e correct position while the concrete remain s plasti c. 416.8.1.3 The concrete is properl y consolidated around the embedded item.
Associ ation of Structura l Eng ineers of tile Pl1i!ippines
CHAPTER 4 - Concrete
4·95
417.3.4 In s trength co mpu tation s or com pos ite me mbers, no distin ction shall be Ill ude betwee n ~ h o l'cd and unshored members.
417.3.5 All elemenl s shall be designed 10 suppon all loads introduced prio r 10 full develo pment o f design strength of composite me mbers.
417.1 Notations
A,
::: area of conlnel surface bei ng ili vestiglllcd for hori zon lal shear, Illn/ ::: area of tics wi thi n a d ista nce s, 111 m 2 ::: width of cross section at comae ! sur face being
h
in vestigated for hori zolllal shear, mill = distance from ex treme co mpress ion nbcr (0 centroid of tension rein fo rce ment for entire composite section, mill = overall thi ckn ess of composite members, mm
s
::: spacing of ties measured along the longi tudi nal
p"
ax is of Ihe member, 111111 ::: nominal hOJizont a) shear strength ::: facto red shear force a l sec tion :: correction factor re lated to uni t weight of concrete ::: ralio of tic rcinforccmc ni area (0 a rea o f co/uac!
d
sUlface
p,.
417.3.6 Rei nforcement shall be provided as requ ired to contro l crack ing and to prevent separation o f indiv idua l clements of composi te members. 417.3.7 Compos it e members shall meet requ irement s for control of denection s in acc ordance with Section 409. 6 .5.
417.4 Shoring Whe n used, sholing shall not be re moved until supported cle ments have developed design properties requi red to suppan all loads and limit defl ections and cracking at time of shori ng remo val.
417.5 Vedical Shear Strength
=~
417.5.1 When an entire composite member is assumed to resist vertical shear, design shall be in accordance with requiremcnts of Sccti on 411 as for a monolithicall y cast membcr o f the same cross-scctional sha pe.
b,.s
;;: strength-redu cti on factor. Sec Section 409 .4
417.2 Scope 417.2.1 Provisions of Section 4 17 shall app ly for design of co mpos ite conaete flexura l members defined as precast or casl-in-p lace concrete clcmelHs or both consllucted in separate placemell ts but $0 intercon nec ted thm ,I II c leme nts respond 10 loads as a unit. 417.2.2 All provision s of this code shall nppJy 10 compos ite concrete fl e xural ll1 e mlH~ r s, except as specifi cally modi fied in thi s Secti on.
417.5.2 Shear reinforcement sha ll be fully anc hored into interconnected elements in accordance with Section 412.14. 41 7 .5.3 Ex tended and a nc hored shear reinrorce mem shall be pCJ'ln itlcd 10 be incl udcd as lies for ho ri zon(a l shear.
417.6 Horizontal Shear Strength 417.6.1 in a compo:> ite member, full transfer of horizollwl shear forces shall be assured at contac t surfaces of intercon nected e lements.
417.3 General 417.3.1 The usc of an e ntire composite member or portio ns thereo r for resistin g shciIf illld mo me nt s ha ll be permitted . 417.3.2 Individual cJerlH.:llt s shall he critical stages or loading.
in vcs tigat(~d
for all
417.6.2 For the prov isions of 4 17.6, d shall be taken as the distance from ext re me co mpress io n fi ber ror enure co mpos it e sec tio n 10 cent ro id or prcslressed and nonpresll'csscd longilll di na l tension rcinforccment, if any, but need 110t be ta ke n less than (l .BOh for prestressed
concrete members.
417.3.3 If the s pc(.; ificd stre ngth . unit we ight or other pro pcI1ics of lhe va ri olls dements are d ilTc rcll l, propert ies of the individual clelllc llls or the mos t criti cal va lues sh:1I 1 he used in dc."ign.
National Structural Code of HIe Pililippin os G!1l Edition Volllrll e 1
4·96
CHAPTER 4 . Conerele
417.6.3 Unless calculated in accorda nce with Seclion 417.6.4. design of cross sections subject to horizontal shear shall be based on (4 17- 1)
where Vol is factored shear force a[ secti on considered and V II}, is nominal hori zontal shear strength in acco rd ance with Ihe foll owin g: 417.6.3.1 Where C('l1~:ICt surfaces arc clear, free of lai tancc an d intemionall y roughened, shear strength V,III shall not be take n grea ter tha n O.55b,d, in newtons.
417.7 T ics ror Hori zont al Shea r 417.7.1 When ties arc provided to transfer horizontal she;~;-. tie area shall not be less than that requ ired by Sec!i\!q 4 11 .6.5.3 and tic spacing shall not exceed four times th:' Icas t dime ns ion or supportcd clement. or 600 mm. 417.7.2 Tics for hori zo lllal shea r shall consist of single bars or wire, mUltiple leg stirrups. or vCrli callcgs of welded v,
417.6.3.2 Where minimum ties are provided in accordan ce wilh Section 417.7 and contact surfaces are clean and free of laitance, but not intentionally roughened, shear strength Vnh shall not be taken greater than O.55b,.d. in newtons. 417.6.3.3 Where min imum ties are provided in accordance wit h Section 417.7 and contact surfaces arc clean, free of lai l3nce. and int entionally roughened to a fu ll ampl itude of app rox imately 5 mm, shear strength Villi shall be taken equal 10 ( 1,8 + O.6pJ,)J.b,d in newlon" but not greater th an 3.Sb,d, in newlons. Values for ..l in Seelion 411.8.4 .3 shall apply, and P. is A.I(b,s). 417.6.3.4 Wherc facto red shear force VII at sectio n considered exceeds ¢ 3.5I>"d, des ign for horizo ntal shear shall be in accordance wit h Section 411 .8.4. 417.6.3.5 Where detemlining nominal horizontal shear st rength over prestressed concrete elements. d shall be as defined or 0.8h, whichever is greater. 41 7.6.4 A s an alternative (0 Section 417.6.3. hori1.oJlt;.tI shear shall be permiLled (0 be detcnni ned by compu ti ng the ac tual change in compressive or tensile fo rce in any segment. and prov isions shall be made to tra nsfer th at fo rce as hori zo nt al shear to the support in g elemen t. The fac tored hori zo nt al shear force shall not exceed hori zont al shear strength ¢V"h as givcn in Secti ons 417.6.3. J throu gh 417 .6.3 .4 wh ere area of contact slIrfnce A(' shall be substituted fo r b,ll. 417.6.4.1 When tics provided to resist horiwl1laJ shear are designed 10 satisfy Section 417.6.3, the rieMarca-loMt ie M spacing ralio along Ihe l;lCJ;lber shall approxim.ucly reflect the distrihuli oll of s hear forces in tile member. 417.6.5 Where tension exists across any contact surface betwecn intcrcon nected clements. shear transfer by contact
may be assulllcu only when minimum tics arc provided in :Jccordancc with Section 417.7 .
Association of S tr uctural Englr1eers of the Phil ir>Plnes
CHAPTER 4 . Concrete
N..
p$ 1',
Pw 418.1 Notalions
A
a
:::: urea of that pm1 of cross secti on between flexural ~~~~~()Il face and center of gravity of gross section,
= larger gross cross-sec tional arCH or the slab-beam strips of the two ol1hogo nnl equiva lent frames
intersecting al
fJ, Ifl
A.
111m2
A,
A; b D d
d·
::;: area of nonprcstressed tension reinforcement, 111m2 ::;: area of compressio n reinforcement, mm 2 = width of compression face of member, mill :::: dead loads or related internal moment s and forces ::::: distance from ex treme compression fiber to ce nt roid of nonprestressed tension reinforcement, min :::: distance from extreme. compression fiber to
centroid of co mpression reinforcement, mm
e
:::: distance from extreme com pression fiber to centroid of prestressed reinforcelnc lll, mm ;:: basc of NapicJian logarithms ;:: spccified comprcss ive strength of concre te, MPa ;:;: square root of spec ifi ed compressive strengt h of co ncrete, MPa
F,,;
;:: compress ive strengt h of concrete ilt lime of initial
J,IU
prestress, MPa ;:: avcmge co mpress ive stress in con cretc duc (0 effective prestress force only (aner allowance for all prestress losses). MPa ::: stress in prestressed rcinforcclIlclll at nomina l st re ngth, MPa ;:: specified tensile strength of prestressing tc ndons ,
/py
;:;:
1,.
::: modulus of rupture of concrete, MPa ;:: effective st ress in prestressed reinforcement (after
/,,,
J,u
J.1
P p'
4·97
tensile force in concrete due to unfactorc.d dead load plus live load (D + L) prestressing tendon force aljack ing end = prestressing tendo n force at any point x ;:: factored pos t-te nsioned tendon force at the anchorage device ;:: total angular change of prestressing tCllu on profile in rildians from te ndon jacking end 10 ,IllY poill! x = factor defined in Sec tion 410.3.7.3 ;:: factor for type o f prestressing tcndon . = 0.55 for .!"//,,, not less than 0.80 = 0.40 for /,,,I/,," not less than 0.85 = 0.28 for /,,,11,,,, not less than 0.90 = correction faclor rclated 10 un it weight of conc rete (See Sect ion 411 .8.4.3) = curvature friction coefficient = ratio of nonprcstressed tension reinforcemcnt = A,!{bd) =. ratio of com pression reinforcement ::0:
=
= A, "/(bd)
PI'
= ratio of prestressed reinforccment
¢
= A,,/(bdp ) = s{rcngth~rcductioll factor. See Section 409.4 = pl/F,
OJ OJ'
=
WI' = 00 .... WI""
p·I/F, Pr/p/j',· (j)' ". ;:: reinforcemc nt indices for flanged sections compu tcd as for (U, Uf.. and oJ except that b sh'lll be the web width, and reinforcement area sha ll be thaI req uired to develop compressive stre ngth of web on ly
418.2 Scope 418.2.1 Provisions of this Sec lion sha ll apply 10 members prestres sed wi th wire. strands or bars conrormi ng to provisio ns for prestressing tcndo ns in Section 403,6.6.
MPa specified yield strength of prestressi ng tendons,
MPa f(~,
1,. "
K
II I, 11
allowance for a ll prestress losses), MPa = specified yield strength of nonpreslrcsscd rcinforcement, MPil ;:: ove rall dimcns ion of me m ber ill direction of action co nsidered, 111111 = wobble fri ction coellicient per 111 III of prcs trc.~s ing tendon ;:: length of prestressing tendon clement from jacking end to any point x. m. See Eqs. 4 18- 1 ,lIld 4 18-2 = Ji ve IOi.1ds or rci;l1ed internal moment s and forces = number of Illonoslrand anchorage devices in . 1
418.2.2 AI! provisions of this code not specifically excl uded, anc! not in conflict with provisions of thi s Section, shall apply to prestressed concrete. 418.2.3 The fo llowin g provisions or this code shal l not
it pply to prcstressed concrete, ext'cpt as specifically noted: Secti ons 407.7.5. 408.5 . 408.11.2 through 408 . 11 .4. 408.12, 4 10 .4.2 and 410.4.0 , 410.6 . 410.7, 410. 10. 1. 410. 10 .2. 4JJ . 41 4 .4 . 414.6 and 414.7.
group
National Siruct urni Cod,,; of th e PililiPPU18S G!h Edition V()lurnC 1
4-98
CHAI'TE" 4 - Concrete
418.3 Gelleral 418.3.1
Prestressed members shall meet the strength
requirements specified in this code.
418.4.3 Prestressed flexural members shall be classified as Class U, Class T, or Class C based on h' the computed extreme fiber stress in tension in the pre-compressed tensile zone calculated at service loads, as follows: I.
Class U: J, S O.62Jl
2.
Class T: 0.62J];'
3.
Class C:f, > 1.0J];·
418.3.2 Design of prestressed members shall be based on strength and on behavior at service conditions at all siages that may be critical during the life of the structure 1'1'0111 the time prestress is first applied. 418.3.3 Stress concentrations due to prestressing shall be
Prestressed two-way slab systems shall be designed as Class
considered in design.
U with!, :0 O.SOJ];·.
418.3.4 Provisions shall be made for effects on adjoining
construction of elastic and plastic deformations, deflections, changes in length and rotations due to prestressing. Effects of temperature and shrinkage shall also be included. 418.3.5 Possibility of buckling in a member between points where concrete and prestressing tendons are in contact and of buckling in thin webs and flanges shall be considered. 418.3.6 In computing section properties prior to bonding of
prestressing tendons, effect of loss of area due to open ducts shall be considered. 418.3.7 The serviceability requirements for each class are summarized in Table 418-1. For comparison, Table 418-1
also shows corresponding requirements for nonprestressed members. 418.4 Design Assumptions
The serviceability requirements for each class are summarized in Table 418-2. For comparison, Table 418-2 also shows conesponding requirements for nonprestressed members. 418.4.4 For Class U and Class T flexural members, stresses at service loads shall be permitted to be calculated using the uncracked section. For Class C flexural members, stresses aJ service loads shall be calculated using the cracked transformed section. 418.4.5 Deflections of prestressed flexural members shall be calculated in accordance with Section 409.6. 418.5 Permissible Stresses in Concrete - Flexural Members 418.5.1 Stresses in concrete immediately aftcr prestress
418.4.1 Strength design of prestressed members for flexure
and axial loads shall be based on assumptions given in
transfer (before timc-dependent prestrcss losses): I.
Section 410.3, except that Section 410.3.4 shall apply only
to reinforcement conforming to Section 403.6.3. 418.4.2 For investigation of stresses at transfer of prestress, at service loads, and at cracking loads, straight-line theory shall be lIsed with the following assumptions:
Extreme fiber slress in compression permitted in (2) shall not exceed
except
a:;
0.60/,,,
2. Extreme fiber stress in compression at ends of simply 0.70// supported members shall not exceed... 3.
Where computed concrete tensile strength,;;,
O.5J);'~ at ends of simply
Jl,
other
0.25
load range.
reinforcement shall be provided in the tensile 7-01':,' iii resist the total tensile force in concrete computed \vifll the assumption of an uncracked section.
Association of Structural Engineers of the Philippines
locations,
members, c'
418.4.2.1 Strains vary linearly with depth through entire
418.4.2.2 At cracked sections, concrete resists no tension.
at
supported
excccd~;
additional
bop·-; '"
CHAPTER 4 - Conerole
418.5.2 For Class U and Class members, stresses in co nc rete at uncracked sect ion properties, and prestress losses shall not exceed the
T prestressed n ex u!"al service loads based on after allowance for all foll ow ing:
I. Extreme fiber stress in compression due plus sustained loads. . . . . . . . . 2.
prestress . ... ... 0.45/"•. 10
418.6 Permissible Stress in Prestressing Tendons 418,6.1 Tensile stress in prestressing tendons shall not exceed the following:
I.
2.
that performance will not be impaired .
Due La prestressin g tendon j acking force
.. _. O.94J;,),
but 110t greater than the lesser of 0 .80 J"u and the maximum va lue recomme nded by manufacturer of prestressing te ndons or anchorage dev ices.
Extre me fiber stress in compression due to prestress plu s to tal load .. ... . . . . . . .. .. .. 0.60/"•.
418.5.3 Permissible stresses in concrete of Secti ons 418.5.1 and 418.5.2 may be exceeded if shown by lest or analysis
4·99
3.
. .0.82/py
Immediately afte r prestress transfer .. . but not greate r than ........ _....... _...... . P os t ~ tensioning
tendons.
at
... 0.74/,"
anchorage
devices
and couplers, immediately after force transfer. , ,.70J,,,,
418.5.4 For Class C prestressed fl ex ural members not
su bject
10
fatigue or
lO
aggressive exposure, the spacing of
bonde d reinforcement nearest the extreme tension fa ce shall not exceed thal given by Section 410.7.4
f or structures subject to fatigue or exposed to corrosive ellv ironments, invest iga ti ons an d precautio ns are required . 418.5.4.1 The spac ing requirement s shall be met by Ilonprcstrcssed reinforcement and bonded tendons. The spacing o f bonded tendons shall no! exceed 2/3 of t!lC maximum spacin g permitted for Ilonprestressed reinforcemenl. Wh ere both reinfo rcement and bonded te nd ons are used [Q mee t the spaci ng requirement, the spacing between a bar and a tendon shall not exceed 5/6 o f th al permi tted by Sec tion 41 0.7.4. See also Section 418 .5.4.3. 418.5.4.2 In applyin g Eq . lOA to prestressing tendons, A.ft,,\ shall be substituted for .f..., where ~r" ., sha ll be takcn as the calculated stress in the prestressing stee l at servi ce loads based on a c racked section analys is minus the decompressio n st ress hl("' It shall be penn itled to take /d,' equal to the effective stress in the prestressing steel [,,,. Sec also Section 418.5.4.3 . 418.5.4.3 In applying Eq. 10-5 to prestressing tendons, the magnitude of 6/"s shall not exceed 250 MPa . When AJ;" is less th an or equal to 140 MPa, the spacin g requirement s of Sections 418.5.4.1 and 418.5.4.2 shall not apply. 418.5.4.4 Where h of a bea m e xceed s 900
III III ,
the area
or
iongiludi ll:ll ski ll reinforcemen t consistin g of reinforce lne ll!
or bond ed tendo ns shall be prov id ed as required by Section
410.7.7.
418.7 Loss of Prestress 418.7. 1 To derermine effective prestress fm allowance for the following sources of loss of prestress shaJl be co nsidered: I.
Te ndo n sealing at lransfe r;
2.
Elastic shorten ing o f co ncrete;
3.
Creep of concrete;
4.
Shrinkage of con crete;
5.
Relaxation of ICIl
6.
Friction loss due to int en ded or unintended curvalUre in post-tens io ning tendons .
418.7.2 Friction Loss in Post-Tensioning Tendons 418.7.2.1 Pp, force in pos t-tensionin g tendons a di stance ',,, from th e jacking end shall be comput ed by:
) - ( KI P px = I 11je
fI'
~. /f
f!
a
I"
)
When (KI11.,+J1P CI,I.t) is not greater than OJ, permitted to be computed by:
(41 8- 1) P 11,C
sha ll be
(418·2) 418.7.2.2 Friction loss sha ll be based 0 11 experime ntally determin ed wobble K .~uld curvature P I' frictio n coeffi cie nts and shri ll be verified duri ng tendon stressi ng operations. 418.7.2.3 Values o f K and p J' coenicien ts used in design shall be shown on design drawings. 418.7.3 W he re loss o f pres tress in member ·may occur due to connecti on of me mber to IIdj oi ni ng cons tmc li o n, such loss of prest ress shall be IIl10wed for ill des ig n.
N8tional Structural Cod e of Ille Philippines (/' Edition Volume 1
4· 100
CHAPTE R 4 · Concrele
418.9 Limits for Reinforcement of Flexural
418.8.1 Design moment st rength of fl ex ural members shall
418.9.1 Pres lressed concrete secti ons shall hr ! '.! '. ' :'>-d 's c Hher I c n s ion ~c onlroll ed . transition, or (OlliP:""::, j
be computed by the strength des ign methods of this chapter.
For prestressing tendons, ];,.1' shall be subst ituted for ,h. in strength computations. 418.8.2 As an ahcrnati vc to a more accu rate determination Oil .strain compatibility, the following "J)[Jl'Oxirnatc va lues OfJ,~f shall be permitted to be used if IS( is nol Jess Ihan 0.5/,,;.
(,; If'S based
I.
For members with bonded tendons:
I 1" = I ,.., (I - ~[p ~ (0 PI 1',. +..!!-. d ,. I'
(O 'J])
(418·3)
where", is pl//e' , ",' is pJ//e', and YP is 0.55 for 1./1.. nol less Ihan 0.80; 0.40 for /,.//,.. nol Jess Ihan 0.85; and 0.28 for1.//'", nol less Ihan 0.90. If any cOlilpression rein forcement is lakcn into account when calcu lnling J,.s by Eq. 4 J 8·3. the term
[
P p -f,,,,, f ~
d (
+ - --{/)-{U
.
'J]
2.
(/1)'
For members with unbonded to-dcpth ratio of 35 or less:
+70+~ / P;/ '" 100
tendons and with a span -
(4 18·4)
P"
but /,,, ill Eq. 418-4 shall not he I
f,,, ; / " + 70
+3~' .
(418·5 )
P"
but /,,, ill Eq . 418-5 shall not he takcn grea ter than /;')" nor grcillcr tlw n
418.9,2 Total ilmounl I of prestressed and 1l01l111 :'Slrc.ssed reinforcement in members with bonded pres;),' \SI: d reinforcement shall be :Idequate to develop a fal;lorclj w.hl at least 1.2 times the cracking load computed \ )1: th:' i,;:, !". '~ f (he modulus of rupture fr specified in St'( ", . .!!!";: -~ This provision shall be permincd to bc W 1U Yc! ,(': . • "", members with shear and flexural st rength a ll ea ~;l !9!:ce \iii\! required by Seclion 409.3. 418.9.3 Part or all of the bonded reinforcclJ !!'i,; l om;i :;li! of bars or tendons shall be provided as clos!: :.'; !,::w! lc ab lt to the tensi on face in prestressed nex ural lllcmlwf s. In members prestressed with unbonded tendolls, fl:i . fl,':! I Il1Ul l' bo nded reinforcement consisting of bars or K n<.loll:'> ~.~, ;; !I b·' as required by Sccli on 418. I O.
418.10 Minimum Bonded Reinforcement
til'
:-; hall be taken not less tha n 0.17 and d' shall be no
greater thill) 0 . 15
3.
Mt.~lllbt.!l-S
418.8 Flexural Slrenglh
NOll prcs trcsscd rei nforcc mellt con forming to Section 403 .6.3 , if lIsed with prestressing tendons, 511<111 be pc rmi!1cd to he considered 10 contribute 10 the tensile force and 10 be included in moment stren gth co mputations at .1 strcss equal to the specified yield strength fro Other nonprcslresscd reinforceme nt shall be permitted to be included in strength computatiolls onl y if a strai n cOlll p.Hibili ty analysis is made 10 determine stresses in such reinfo rcc rncnt.
418.10.1 A minimum area of bonded rcinfor('cl'twJ'd . . Id l !II . provided in all fl exural members wiill UiJtollfi(.i i prestressing tendons as required by Sect ioJ)!: ·1 :::.iiJ.1.. : 'I!: 418.10.3. 418.10.2 Except as provided in Section 41 8.IOJ. IIl:Hi mull area of bonded reinforce ment shall be COl1l rHlkd hy:
A, = 0.004A,., where ACl is area of thai part of cross seelie:, i){'t".'!,· n i!, nexura l tension face and ce nt er of gravity of i:.' .,;.:.. :,' , ', .;,. 418.10.2.1 Bonded reinforcement requin~d ~.,' i .• ; . shall be uniformly distributed over prC-C\lI :li" " :""~ \l:'} zo ne as close as practi ca ble to extreme ten siUli iii;;;. 418.10.2.2 Bonded rei nforcement sh,lIl rega rdless of service load stress conditions .
f,'
:: ;
lei!"; ',
418.10.3 ror two-way flal slab syste ms, . mi r:: .. :":l,; ., a ili itj d islribution o f bonded reinforcement shall he , 1•• I . -: '_,;] .:d in Secli on, 4 I 8. 10.3. 1, 4 I 8. I0 .:1.2, and 4 I 8. IOJ.·I. 418.10.3.1 Bond ed rei nforcement ShilJl not i . ;;.. ; .. " positi ve momen t ;lfCa s whc reji, Ihe cxtrcm ' '. -.:,' tension in the pre~ comp ressed tcnsile lone :~\ ':!': "i,'" i,~·,,1 (afler ;dI OW
J7.: I\ss oCi,:l ti on of Stru ctuml E r1girwGfs of tile Philipp ines
CHAf'TEf1 6 · Wood
r ·.
=
I'~
(;·2l
(618-X)
lnl cnncdialc colullllls (/,.1 d greater than II but less than K): K
(618-9)
619.1 General (618-10)
Long column ( Ir/ d of K or grcillcr):
(618- 11)
618.5 Compression at Angle fo Grain The allowable unit stress in compression at an ilngle of load (0 grain between 0° find 90° shall be computed from the Hankinson Equal iOIl as follows : F = II
I~. f~.J. I;~. sill 1 0 + I~'J. cos] 0
(618- 12)
Allowable values F,: shall be adjusted for duration of load before lise in Hankinson's Equation. Values of F" and 1~J. are not subjected to duration of load modifications . '. ,,:. ,:.:. .... . ,~
Timher co nnectors and fasten ers may be used to transmit forces bet ween wood members and bet ween wood and metal members. 111C allowable loads and installation of timber connectors and fasteners shall be in accard:mce with the tables as provided ill th.is Chapler. The allowable IOHds and installation of timber connec tors shall be (\s set forth in Tables 6.2. 6.17. 6 . 19. and 6.20. Safe loads and design practice s for Iypes of connectors and fasteners not mentioned or fully covered may be determined ill a manner permiucd by the Building Official. 619.2 noll' Safe loads in kN for bolts ill shear ill se.asoned lumber shall
not exceed the values sci forth in Table 6.17. Allowable shear values used to co nnect a wood LO concrete or masonry are. permitted to be determined as olle half the tabulated double shear values for a wood member twice the thickness of the member attached to the conCrete or masonry. 619.3 Nails and Spikes 619.3.1 Safe Lateral Strength
A cornman wire nail driven perpendicular to grain of lhe wood , when used to fasten wood members lOgether, shall
not be subjected LO a greater load causing shear and bending than (he safe lateral strength of lhe wire nail or spike as SCI forth in Table 6.21. A wire nail dri vcn parallel to the grai n of the wood shall not be subjected more than two thirds of the lateral load allowed when driven perpendicul ar to the grain. Toenails shall not be subjected more Ih an five sixths of the lateral load allowed for nails driven perpendicular to the grain. 619_3_2 Safe Resistan ce to With,h-awal A wire nail driven perpendi cuhlf" to grain of wood shall nol be subj ec ted to a greater load, tend ing to cause withdrawal , than the safe resis(ance o f th e ·nail to withdraw al, as sct forth in Tabl e 6.21.
1h
Nalionai Siruciural Code of Ihe Philippines 6 Edilion Volume 1
6·28
CHAPTEH G . Wood
619.3.3 SI)acillg and Jlent'trtllion Common wire mliis shall have penetration into the piece receiving the point as SCI forth ill Table 6.21. Nails or spikes for which the wire gauges or lengths Elrc not sct fOrlh
PO
in Table 6.2 1 shall have a required penclnttion of lIot less than II diameters, lind allowable lond s ma y be inlcrpoliUcd.
Design values shed! be increased whell the pe netratioll of nail s into the member holding the point is larger than the required by Ihi s item.
'j .
HOt Olt-.G LU;MBt-:A
-1-- .
I,
SlOF.R
' fABlII.A1EO • l~ OSARI:
j
PiR
I/oCHef PENHRAPClN
For wood· to-w(lod jOints, the spacing center to center of nails in the direction of stress shall not be less than one half of lhe required pcnctralion. r=.dgc or end di sta nces in the direction of stress shall not be less one ha lf of ehe required penetration. All spacing and edge and end distances shall be suc h as to avoid splitting of the wood.
Figure 619.5.2 -A: Basic Withdrawal ConnCl'ti uH
r
SIDE R -"
NAIL
--_\~-
:rl -~-- H~~~~;
Hol es for nail s, where necessary to prevent spliuing, shall be bored of a diameter smalle r than th at of the nail s.
1-
6J 9.4 Joist Hangel"s and Framing Anchors
I
Con nections depending upon joist ha ngers o r rraming an chors, tics and other mechanical ra ste nings no t otherwise covered may be used wtlcrc
MEMBER
P
Figurc 6J9.S.2-U: Withdrawal from End-Grain
619.5 Miscellaneous Fasteners
(not allowed)
619.5.1 Drift Bolts or Drift Pins Connections involving the li se or drirt bolts or pillS sh<.11I be designed in accordance with the provisions set fOll h in this
Chapter.
StDE MEMBER "
PI2
1,~~""
__ ~ WITHDRAWAL
P--
./ __
MAIN MEMBEll
619.5.1.1 Wood Screws and Lag Screws Wood and lag screws shall be used where there is limited penetration, especially in a withdrawal design, as these provide greater resistance. Design of th e sc rews shall be in accord ance with the provjsion s set fOl1h in thi s Chapter.
619.5.1.2 Withdrawal Design Va lues Drift boll and dlifl pin connections loaded in withdrawal shall be designed in accordance with good engineering pmctice. Fi gures 619.5.2·A to 619.S.2-C are exa mpl es of withd rawal connecti ons.
PI2
I
Figure 6J9.S.2-C: Tocnail Connecti oIl Withdrawal from
Side Gr~,in 6 19.5.1.2 Laleral Design Va lues Allo wable lateral design values for drift bolts and drifl pins dri ven in the side grain or wood shall nOI exceed '/5 Ji;,'r: ,'11I of lhe all owable laleral des ign values fo r common : :
or
th e ~ al11c diameter and Icilgth in main me mber. A{ \:i tj ~ii\a l penetration of pin into members should he provided in lieu o f the washer. head find nu t 011 it com m Oil boll.
619.5.2 Spike G.-ids Wood-Io-wood connection s involving spike grit.ls for hlnal load transfer shall be desig ned in accordance wi!:l od
Associalion of Structural Engineers of the Philippines
I
CHAPTER 4 . Concreto
418.10.3.2 In positive moment areils where computed lensil e stress in concrete at service load exceeds D,l71l'
418. 11 Statically Ind eterminate Stru ctures
minimum area of bonded reinforcement 5h:'11I be computed
by:
A,
=-~ 05/,
where design yie ld strength
(41 8-7)
j;, used in Bq. 418 -7 shall /lot
exceed 4 J 5 MPn . Bonded reinforcement sha ll be uniformly dist ributed over pre-comp resse d tensile zOlle as close as practicahle to extreme tension fiber. 418.10.3.3 In nega ti ve mome nt afC(lS at column supports, minimum area of bonded reinforcement AJ in the lOp of the slab in each direction shall be computed by:
A,
= 0.OO075A,{
(418-8)
where A. j is the larger gross cross-sectional area of the slabbeam strips ililwo oflh ogona l equi valent frames imcrsccLing a t a co lumn in a I wo-way slab.
Bonded reinforceme nt required by Eq. 4 1R-8 shall bc· distributed between lines that are J .511 outside opposite faces of the column suppo rt . AI Icast four bars or wires shall be provided in each di rection. Spacing of bonded reinforcement shall not exceed 300 mlTI. 418.10.4 Minimulll lengt h of bonded re inforccmelll req ui red by Sections 4 18.10.2 and 418.10.3 shall be as required in Sections 418.I0.4. 1,4 ! 8. 10.4.2, and 418.10.4.3.
418.10.4.1 in positive moment areas. minimum Icngtl1 of bonded reinforcement shall be one-third the clear span length, /", and celHered in posi tive mOlllcnl area. 418.10.4.2 In negat ive momen t arC;:ls. bonded reinforcement shall ex tend one-six th the de.l r span, I,,, on eac h side of support. 418.10.4.3 Where bo nded reinforcem ent is provided for design moment stre ngt h, ¢A1., in acco rdance with Section 418.8.3, or for tens il e st ress conditions in accordance with Secti on 4! 8. 10.3.2. minimum length also shal! conform to provis ions of Section 412.
418.11.1 Fr~ ll1 es and COl1linllOUS co nstruction of prcstressed concrete shall be designed 1'01' satisfactory perfo rmance at service load condi tions an d for adequate strgngth . 41H.l1.2 Performance at se rvice load conditions shall be determined by clas ti c ana lysis, c~~lsidc r ing reactions, moments. shears, and
to factored loads. Adjustment of the sum of these moments shall be permiLted as a llowed in Section 4 18.1 1.4. 418.11.4 Redistribution of Ncgativc M011lcnl.'i in Continuous Prestrcssed Flexural Members 418.11.4.1 Where bonded reinforcement is providcd at SUPP011S in accord ance Wilh Section 41 8. 10, it shall be permitted to decrease negative or positive moments calculated by clastic theory for any assli med londing, in accordance with Section 408.5.
418.11.4.2 The reduced moment shall be used for calculating redistributed moments at all other sections within the spans. Static equi librium shall be maintained after rcdistJibution of moments for c,lch loading arrangement. 4J8.12 Compression Members - Co mbin ed F1exm·.. 1 and Axial Loads
418.12.1 Prestressed conc rete mcmbers subject to flexure and axial load, with or without nonprcslressed reinforcement, shall be proportioned by the st rength design methods of this chapter. Effects of prest ress. creep. shrinkage and Icmpcralllrc cha nge sha ll he included. co mbined
i1 l
National Structural Code of the Philippines 6 Edition Voltll'llr? 1
4-102
CHAPTEf14 - Concrete
418.12.2 Limits for Reinforcement of Prestressed Compression Members 418.12.2.1 Members with average compressive stress in concrete less than 1.6 MPa, due to effective prestress force only, shall have minimulll reinforcement jn accordance with Sections 407.11, 410.10.1 and 410.JO.2 for columns, or
Section 414.4 for walls. 418.12.2.2 Except for walls, members with average prestress It),. equal to or greater than 1.6 MPa shall have all prestressing tendons enclosed by spirals or lateral tics in accordance with the following:
1. 2.
Spirals shall conform to Section 407.11.4; Lateral ties shall be at least 10
n1l11
diameter in size or
welded wire fabric of equivalent area, and spaced
vertically not to exceed 48 tie bar or wire diameters or least dimension of compression member; 3.
Tics shall be located vertically not more than half a tie spacing above top of footing or slab in any story, and shall be spaced as provided herein to not more than half a tic spacing below lowest horizontal reinforcement in members supported above;
4.
Where beams or brackets frame into all sides of a column, it shall be permitted to terminate ties not more than 7S mIll below lowest reinforcement in such beams or brackets.
418.12.2.3 For wall.s with average prestress J;". equal to or greater than 1.6 MPa, minimum reinforcement required by Section 414.4 may be waived where structural analysis shows adequate strength and stability. 418.13 Slab Systems
418.13.1 Factored moments and shears in prestressed slab systems reinforced for flexure in more than olle direction shall be determined in accordance with provisions of Section 413.8, (excluding Sections 4 t3.8.7.4 and 413.8.7.5), or by Illore detailed design procedures. 418.13.2 Moment strength, ¢M" of prestressed slabs required by Section 'f09,4 at every section shall be at least equal to the required strength Mil, considering Sections 409.3, 418 . 11 J and 4 I 8, 11.4. Shear strength f&V", of prestressed slabs at columns shall be at least eqllal \0 the required strength considering Sections 409.J, 411.2, 411.13.2 and 411.13.6.2.
be met, with appropriate consideration of the factors listed in Section 418.11.2. 418.13.4 POI' uniformly distributed live loads, ;;pacing of tendons or groups of tendons in at least one di!l:dion shaJi not exceed the smaller of eight times the slab thickness, and I.S m. Spacing of tendons also shall provide a :ninimum average prestress of 0.9 MPa on the slab section tributary to the tendon or tendon group. For slabs with v;,; \ing cross "ndicular section along the slab span, either parallel or to the tendon or tendon group, the minill1: :;" "·/erage effective prestress of 0.9 MPa is required
418.13.5 In slabs with unbonded prestressing tendons, bonded reinforcement shall be provided in accord :-.lIlce with Sections 418.10.3 and 418.10.4. 418.13.6 Except as permitted in Section 418.J3.7, in slabs with unbonded tendons, a minimum of two 12 m:n diameter or larger, seven-wire post-tensioned strand.,; shall be provided in each direction at columns, eithu passing through or anchored within the region bounded by the longitudinal reinforcement of the column. OUWdc. columJl and shear cap faces, these two structural inlC jil'tendons shall pass under any orthogonal tendons in adjii',:clll spans. Where the two structural integrity tendon~: irC!t'.lICd within the region bounded by the longitudinill " ::!;" r CHJ(.n! of the column, the anchorage shall be \oC<11e :: tbe: column centroid and away from the anchored si .:il.
418.13.7 Prestressed slabs not satisfying Se_, ::\)11 ':J~\.13.6 shall be permitted provided they C(:: \;ottOlll reinforcement in each direction passing wilhiii !'('ginn bounded by the longitudinal reinforcement of 1\1, and anchored at exterior supports as required by Scc!iul1 41 J.4.8.5. The area of bottom reinforcenK!'~ c/" direction shall be not less than 1.5 times that !,\' I 410-3 and not less than 2.1b"LlIf"" where b" i': [1:: 1\ ,i: the column face through which the reinfo: Minimulll extension of these bars beyond th · cap face shall be equal to or greater li:; development length required by Section 412.2 L 418.13.8 'In lift slabs, bonded bottom reinforcelllcli: :,)i:,:' be detailed in accordance with Section 4IJ.4.~U'
418.13.3 At service load conditions, all serviceability limitations, including specified limits on dellcctions, shall
I\sSOCii1tIOIl of Structural En9ineers of the Phitippines
CHAPTER 4 - Concrete
4·103
418.14 Pos t-Tensioncd Tcndon Anchorage Zones 418.14.1 Anchorage Zone The Hnchorage zone sha ll be considered as composed of two zones: I.
The 10c.1I zone is the rectangular prism (or cquiv'l lent rectangular prism for circular or ova l anchorages) of co ncrete immedimely su rrounding the anchorage device and any confin ing reinforcement;
2.
The general zone is the anchorage zone as defined Section 402 and includes the local zone.
Ifl
418.14.2 Local Zone 418.14.2.1 Design of local zones shall be based upon (he factored tendon force. PJ u • and the requirements of Sec tions 409.3.5 and 409.4.2.5 418.14.2.2 Local-zone rei nforcement shall be provided w here req uired for proper fu ncti on ing of the anchorage device. 418.14.2.3 Local-zon e requirements of Section 418.14.2.2 are satisfied by Sec ti on 418. I 5.1 or 418 .16. I and 418 . I 6.2.
418.14.4.2 Exce pt for conc rete confined within s pirals or hOOp5 providing confinement equivalent to that corresponding to Eg. 410~6, nomin al compre5sive strength of concrete in the general zone shall be lim ited 100.7 )f(,;. 418.14.4.3 Compressive strength of concrete at time o f posHensioning shall be s pecified in the contract documents. Unless oversize anchorage devi ces are si7..cd to co mpensate for the lower compressive strengt h or the tendolls arc st ressed (Q no more than .50 percell( of Ihe fin al tcndon force, tendons shall not he stressed until co mpressive strength of concrete, as indicated by tes ts consistent with the curing of the member, is at leasl 28 MPa for multi strand tendons or at least l7 MPa for single-strand or bar tendons. 418.14.5 Design Methods 418.13.5.1 Th e following methods shall be permitted for the design of general zones provided that the specific procedures used result in predi ction of strength in substantial ag reement with results of comprehensive tests:
I.
Eq uilibrium models);
2.
Linear stress analys is (inclu di ng fini te element ana lysis or equ ivalent); or
3.
Simplilied equations where applicable.
418.14.3 General Zon e 418.14.3. 1 Design of general wnes shall be based upon the factored tend o n force, P fU , and Ihe requirements of Sections 409.).5 a nd 409.4 .2.5 418.14.3.2 Gene ra l-zone reinforcement shall be provided where required to resist bursting, spallin g, and longitudinal edge. IClls io n forces induced by an chorage devices. Effects of abrupt change in sectioll sha ll be considered.
418.14.3.3 The gClIcrHI-zone requircmelHs of Section 4 18. 143.2 are satisfied by Sections 418.14.4, 4 18.14.5, 418.14.6 and whichever one of Section 4 I 8. 15.2 o r 418. I 5.3 or 418. 16.3 is applicable. 418.14.4 Nominal Material Strengths 418.14.4.1 Nominal te nsile streng th of bonded reinforcemcnl is limited to J,. for l1onprcstrcs$ed reinforce ment ;md to h,,' for pres tressed rcin forceme nt Nomina l tensi le stress of unhomJcd prestressed rein forcement for resisting tensile forces in th e anchorage zone shall be limited to!,,)::; h .. +70,
based
plasticity
models
(stnn-nnd-tic
418.14.5.2 Simplified equations shal l nOl be lIsed where member cross sections arc Ilonrectangular, where di scontinu ities in or ncar the ge ne ral zone cause deviations ill Ihe force n ow path, w here minimum edge distance is less than 1. 5 times the anchorage device laleral dimensi on ill thai direct ion, or where multiple anchora ge devices are used in OIlier than one closely spaced group. 418.14.5.3 The stress ing seq uence shall be specified on the design drawings and considered in the design. 418.14.5.4 Three-dimens ional effects shall be considered ill design and ana lyzed using three- dime ns iona l procedures or approximated by considering the summation of effects for tw o ort hogonal planes. 418.14.5.5 For intermediate anc horage devices, bonded reinforcement shall be prov ided 10 trilllsfer at least 0.35 p.•" into the concrete section behind {he anchor. Such reinforce ment shall be placed symmetrically around the anchorage devices and shall be full y developed both behind and aheHd o f the anchorage devices ,
Nationa l Structural Code of the Philippines GIll Edition Volume 1
4·104
CHAPTER 4 · Concrele
418.14.5.6 Where curved tendons arc used in the general zo ne, except for monostrand tend ons in slabs or where analysis shows reinforcement is not required, bo nded rei nforcement shall be provided (0 resist mdial and splitting forces. 418.14.5.7 Except for ll1onostrnnd tendoJl!'i ill slabs or where analysis shows
reinforcemclH
is
not
required,
minimulll reinforcement with a nominal (ensile st rength eq ual 10 2 perce nt of each factored lendon force shall be provided in on hogonal directi ons paralic! [ 0 the back face of all anchorage zones to limit spaJling. 418.14.5.8 Te nsile strength of conc rete shall be neglectod in calculaii ollS of reinforcement rcquircmcnLs. 418.14.6 Detailing Requirem euts Selection of reinforcemen t sizes, spacings, cover, and other dcwils for anchorage zones shall make allowances for tolerances on the bending, fabri cation, and placement of rc.inforcemcnI, for th e size of aggregate, and for adequ ate placement and consol idation of th e concrete.
418.15 Design of Anchorage Zones for Monos trand or Single 16 nlln J)iamctcf B~lr Tendons 418.15.1 Local Z
MOllostrand or single 111 16 111111 or smallcr b'lf anchorage devices and local lone reinforcc mcm shall mcel the requiremen ts of the AC I 42.1.7 or thc special anchorage dcvi(.:c requirem ents of Section 418. I 6.2. 4J8.15.2
Gellc r al~'l'..A)IIC
Design for Slab Telldons
418.15.2. 1 For anchorage devices ror 12 mill or smalier diameter strands in nonnalweight concrete slabs, minimum rcinforccmc.1l1 meeting the requirements of Section 418 .15.2.2 and 418.15.2.3 shall he provided unless a dClniled
conside red as a grollI'. For each group of six or mOre nnc.:horagc devices, Il+J hairpin bars or closed .o;ti rrllps at leas t 10 mill diameter in size S h ~l l\ be provi{kd . wlK'.re II is the number of anchorage devi ces. One hairp in b~lr or stirrup shall be placed bCIwecn eac h nnchorage lJcvicl: and one On eac h side of Ihe group. The haiq)in bars 01" sli n·nps shall be placed with the legs cxtending into the slab perpendicular to the edge. The ce nt er portion of [he ha ilpin bars or stirrups shall be placed perpendicular to the ,;lane of the slab from 3"'8 10 hJ2 ahead or the anchorage deVIces. 418.15.2.4 For anchorage devi ces /lot conforming 11) Section 4 18.15.2.1, minimulll reinforce ment shall be b:.lscd upon ;\ detailed analysis satisfying Scction 418. 14 .5. 418.15.3 Gencral·Zone Design for Groups of Monost rand Tendons in Beams and Girders
Design of general zones for groups of m0l1o»11 :l nd iendon$ in beams and girders shall meet Ihe requiremelll:-> or Sections 4 18.14.3 Ihrough 418. 14.5. 418.16 Design of Anchorage Zones for MuIri s(nm nd
Tendons 418.16. 1 Local Zone Design l3asic mu ltist rand tlnchoragc devices and local zo ne reinforcement shall meel the requirement ::; 'II" t\/'.S HTO "Standard SpecificatitJl1.rfor Highway Bridgd, " Division 1, Articles 9.21.7.2.2 Ihrough 9.21.7 .2.4.
Special anc horage devices shall siltisfy (he tests rl~qujred in AASHTO "Standard Spec{(icariolls for fligh ll ·ilY /)ridge s, " Division 1, Art icle 9.2 1.7 .3 and described , II .A.AS HTO "Sumdard Specijlcariolls fnr Highway IJridj;es, " 17111 Edilion, 2002, Division II, Anicle 10.3.2.3. 418.16.2 Usc of Special Anchorage Devices
Where special anchorage devices arc to he 1I~I~d, supplcmental skin reinforcemcnt 5h
Design for general Ihe req uiremenls
Association of Strllc{urai Fnq!neors of the
1.01les
for mullistrand tendons
~hallll1ee t
or Sl'ctions 418.14.3 Ihro !, ~~i ; .: 1~;.: ·1 ..
Phi!ipplne~;
t.
CHAPTER 4 . Concrete
418.17 Corrosion Prot(~ction for Unbondcd Prcstrcssing Tendons
4·10f)
418.19.2.4 Admixtures conforming to Section 403.7 and known to have no injurious effects on grout, steel, or concrete shall be permitted. Calcium chloride shall not be used.
418.17.1 Unbonded tcndons shall be encased with sheathing. Thc tendons shall be completely coated and the sheathing around the tendon filled with suitable material to inhibit corrosion.
418.19.3 Selection of Grout Proportions
418.17.2 Sheathing shall be watct1ight and continuous over entire length to be uhbonded.
418.19.3.1 Propol1ions of materials for grout shall be based on either of the following:
418.17.3 For applications in corrosive environments, the sheathing sl1<111 be connectcd to all stressing, intermediate and fixcd anchorages in a watertight fashion. 418.17.4 Unbonded single strand tendons shall be protccted against cotTosion in accordance with ACt 423.7. 418.18 Post-Tensioning Ducts 418.18.1 Ducts for grouted tendons shall be mortar-tight and nonreactive with concrete, tendons, grout, and corrosion inhibitor. 418.18.2 Ducts for grouted single wire, single strand, or single bar tendons shall have an inside diametcr at least 6 mm larger than tendon dinmcter. 418.18.3 Ducts for grouted multiple Wire, multiple strand, or multiple bar tendons shall have an inside cross-sectional area at leas! two Ii IllCS the cross-sectional area of tendons. 418.18.4 Ducts shall be maintained free of ponded water if members to be grouted arc exposed (0 tcmperatures below freezing prior to grouting. 418.19 Grout for Bonded Prestressing Tendons 418.19.1 Grout shall consist of ponland cement and water; or portland cemcnt, sand, and water. 418.19.2
1.
Results of tests OJl fresh and hardened grout prior to beginning grouting operations; or
2.
Prior documented experience with similar materials and equipment and under comparable field conditions.
418.19.3.2 Cement used in the work shall correspond to that on which selection of grout prop011iol1s was based. 418.19.3.3 Water content shall be minimum necessary for proper pumping of grout; however, water-cement ratio shall not exceed 0.45 by weight. 418.19.3.4 Water shall not be added to increase grout nowability that has been decreased by delayed use of the grout. 418.19.4 Mixing and Pumping Grout 418.19.4.1 Grout shall be mixed in equipment capable of continuous mechanical mixing and agitation that will produce uniform distribution of materials, passed through screens, and pumped in a manner that will completely fil! the ducts. 418.19.4.2 Temperature of members at time of grouting shall be above 2°e and shall be maintained above 2°C until field-cured 50 mrn cubes of grout reach a minimum compressive strength of 5.5 MPa. 418.19.4.3 Grout temperatures shall not be above 32°C during mixing and pumping.
Materials for grout shall conform to Sections
418.19.2.1 through 418.19.2.4.
418.20 Protection for Prestressing Steel
4HU9.2.1 Portland celllcnt shall conform to Section 403 3. 418.19.2.2 W
Burning or welding operations in the vicinity of prestressing steel shall be performed so that prestressing stee! is not subject to excessive temperatures, welding sparks, or ground currents.
418.19.2.3 Sand, if used, shall conform to "S{(mr/ard S{Jec!/iC(/fioll
for Ag;.:!'(?gate for Masonl), Mortar" (ASTM
C! 44) except that gradation shall be permitted to be modified as necessary to obtain satisfactory workability.
Nallonal Siruclul-ai Code of the Philippines
Gill
Eclition Volume -I
4·106
CHAPTEFl 4 • Conerele
4J8.22 Post·Tensioning Anchorngcs and Couplers 4]8.21 Application and Measurement of Prcstl'cssing
Force 4J8.21.1 Prc~trcsslng force shaH be determined by both of th e following methods: I.
Measurement of' steel elongation. Required elongation shal l be dctcnnincd /'rom average load -elonga tion curves for the prestressing steel u';:!.!;
2.
Observation of jacking force on a calibrated gage or load cell or by use of a calibrated dynamometer.
Cause of ;:IIlY difference in force determination between methods J nnd 2 that exceeds .5 percent for prctcnsioncd elements or 7 percent for posl-lcnsiollcd construction shall
be ascertained and corrected.
418.21.2 Where the transfer of force from the bulkheads of pre-tensioning bed to the concrete is accomplished by name cutting pre·stressing tendons, cutting points and cutting sequence shall be predetermined (0 avoid undesired tcmpomry stresses.
418.22.1 Anchorages and couplers for bonded and un bonded tendons shall deve lop at least 95 pen:C-IH of the specified breaking strength of the (lmdons. j;."" wilen It:stcd in an unbondcd condition, without exceeding anti('ip~l\ed set. POI' bonded tendons, anchorages and couplers \hall be located so that 100 perce nt of' th e spcci ned breaking strength of the tendons. j;.". , shall be developed :ll C) ::ical sections after the prestressing steel are bonded ill the member. 418.22.2 Couplers shall be placed ill areas approved by the engineer-all-record and enclosed in hOllsing long ellough to permit lIecessluy movements .
418.22.3 III unhanded construction subject to repet itive loads, special attention sha ll be give n to the possibility of fatigue in anchorages and couplers. 418.22.4 Anchorages. couplers, and end fittings shall be permanently protected against corrosion.
418.21.3 Long lengths of exposed pre· tensioned strand shall be cut ncar the member to minimize shock to concrete. 418.21.4 Total loss of prestress due to unreplaced broken te ndons sha!l not exceed 2 percent of IOlal prestress.
-0
.s
:;'" 0'" ~
0
'0
<:!
'" I--
~
"
OJ
.:c ~
~
"" '"'"
~ .c
(/)
........._.u
. '""
'0
"0
--~---~ ---- -- - ~.- - .- -- . - --
Wire tendons High·strenglh bars ._ .....strand ..•_--_. __ - ----- . 7·wire --~.-- .
., '0
Table 4 ) 8-1 Friction Coefricicnts for Posl·Tensioncd Tendons for Use in Equation 418-1 or 4 18·2
'"'"
~
__ _._-_._
Wobble ClIrv'lturc cienI , JifJ?cr rad ian .•. _---.. .____ ~y.£fflci~~~~~~~cr _~_ _. __...__c()cffi 0.0033·0.0049 O.15-=-0.25 --' . ..- - .O. 08 ·())O
OJ)003·0.0020---.---.
----.-0:1"5:0.25·00016·0.0066 ._.. -.-.--.....--.-.-.•--.. ..---- ----- .. _-- --.
---- ~~.---
O.O033·().0066
O. 05·0 15
7-wirc strand
O.()O33·().OO66
OJ)5·0 15
Wire tendons
0.00 IO·(). 0066
o. 05·() 15
Wire tendons
-
-
0 '0
.t:> ~ ;:;> I--
" '"
'0
'"
'" '"'"
-----
~
~
'" ~
'"
7-wirc strand
----~-- ---- ----
0.00 I(J.(U)()66
L _ _ ...
Association of Structural Engineers of Ule Philippin es
..
-- --~--
OJ)5·0.15
CHAPTE r, 4 . Concre le
Ta ble
4 18~2
4·10 7
Serviceabilit y Design Requirement s
Prestressed Nonprcstrcssed Class T
Class U
Assullled behavior
Transition betwee n
Uncrac ked
Section properties for stress calculation at service loads
Gross sec tion Secti on 4 18.4.4
Allowable stress at trallsfer
Sectio n 41 8.5. 1
ABowabJc compressive stress based 011
Section
uncracked section p,'operties Tensile stress at service loads Sect. 418.4.3
Cracked
Cracked
Sectio n 4 18.4 .4
Crack section Sec li on 41 8.4.4
No requirement
Secli on 41 8.5. 1
Sec ti on 41 8.5.1
No requirement
SeclioIl41 8.5.2
No requirement
No requirement
ft
No requirement
No requirement
Sec t. 409 .6.4.1
Sect. 409.6.4 . 1
Sect. 409.6.2, 409.6.3
Cracked section,
Cracked section,
bilinear
bilinear
uncmckcd and cr acked
Gross section
4 18.5.2
so62 ft
0.62
Sect. 409.6.4. 1 Deflection calculation basis
Class C
Gross section
.... _-_.. _."_ .. _...
--.----~ .
Side skin reinforcement
Modified by Sect. 418.5.4.1
Section 410.7.4
_..•
Cracked seclion
analysis
MI(A s x lever arm). or O.6fy
No rcquirement
Scction 410.7.7
Sec lion 4 10.7.7
No requirement
requirement
Computatioll of Alp.\' orfs for
crack control
Seclion 410.7.4
No
Crack control
Effective moment of inertia
.._ ._.
--
No rcq tl iremell l
National Structural Code
or tl18 Pililippines Gill Edition Volume
1
4·108
CHAPTER 4·· ConcrelO
Table 418-3
ASTM Standard Prestressing Tendons -.-~-~.
Nominal
Nominal
Nominal
Nominal
Diameter,
Area,
mass,
Diameter,
Nomiual Arca,
mIll
mm
2
kg/m
mm
mlll
6A
23.2
9 Sl
54.8
I 1.10
74.2
Type
Seven-wire Strand (Grade 1725)
0.182
7.9
37A
0.294
9.5
51.6
OA05
---_•..-
-.----.---.~
ll.l
69.7
'--.-
---.-.----~
92.9
0.730
15.2
139A
1.094
19.0
284.0
2.230
22.0
387.0
3.040
--_.
_ .. -
12.70 --~.--.---
..
15.24
2
tn,l kghn 0.4 32
98.7
10
140.0
..
12.7
250 Prestressing Bars (Plain)
.
Sevell-wire Strand (Grade IS60)
0.548
-.--"~---~
...
Type
>{(J:l
503.0
3.970
639.0
5.030 . -------_._6.210 -_._.•..•. ...-
_
4.88
... _ - -
4.98
Prestressing Wire
IS.7 ------_ . 19.5
6.35
31.7
7.01
38.6
15.0
,u n.2
181.0
A
271.0
L't:
•• _ _ ~ _ _ u
--.-- . ---~
29.0 ----32.0
794.0
35.0
955.0
----,--~-.-.--.--.--
.
. ........ __ .....•.•._----
_
7.520
Prestressing
Bars (Deformed)
20.0 - - - - _..._... 26.0 ~--
32.0
.. _-------
36.0
.
Association of S!I"lIcturai Engineers
..
or the
Philippines
548.0 806.0 ----~-.-
1019'1
i)
A
,, ..
;-'
, ,(I
CHAPTER 4 ..- Structural Concrete
4109
418.23 External {)ost- Tensioning 418.23.1 Po)-;t-tcll)-;ioning tendons shall be permitted to be external to any concrete section of a member. The strength and serviceability dcsign methods of this code shall be used in evaluating the elfcCls oj" external tendon forces on the concrete structure. 418.23.2 External tendons shal! be considered as unbonded tcndons when computing llexural strength unless provisions are made to effectively bond the external tendons to the concrete section along its cntire length. 418.23.3 Extcrnal tendons shall be attached to the concrete member in a manner that maintains the desired eccentricity between the tendons and the concrete centroid throughout the full range anticipated member derJcctioJ1.
or
419.1 Notations f~
F, .[['
1\. h /"
¢
:::: modulus of elasticity of concrete, MPa, See Section 408.6.1 = sDecified compressive strength of concrete, MPa :::: sqt:are root of specified compressive strength of concrete, MPa yield strength of nonprestresscd reinforcement, MPa :::: thickness of shell or folded plate, mm :::: development length, mm :::: strength-reduction factor. See Section 409.4
: : specified
419.2 Scope and Del1nitions
Extema! tendons and tendon anchorage regions shall be protected against corrosion, and the details of the protection method shall be indicated on the drawings or in the project sped fications.
419.2.1 Provisions of Section 419 shaH apply to thin-shell and folded-plate concrete structures, including ribs and edge mcmbers. 419.2.2 All provisions of this code not specifically excluded, and not in conflict with provisions of Section 419, shall apply to thin-shell structures.
419.2.3 Thin Shells Three-dimensional spatial structures made up of one or more curved slabs or folded plates whose thicknesses are small compared to their other dimensions. Thin shells are characterized by their three-dimensional load-carrying behavior, which is dctcrrnined by the geometry of their forms, by the manner in which they are supported, and by the naturc of the applied load.
419,2.4 Folded Plates A class of shell structure formed by joining flat, thin slabs along their edges to create a three~climensional spatial structure.
419.2.5 Ribbed Shells Spatial structures with materia! placed primarily along certain preferred rib lines, with the area between thc ribs filled with thin slabs or left open.
419.2.6 Auxiliary Members Ribs or edge beams that serve to strengthen, stiffen, or support the shell; usually, auxiliary members act jointly with the shell.
Nation,·)1 Structural Code of the Philippines 6
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Edition Volume 1
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CHAPTER 4 -- Siruciural Concrelo
419.2.7 Elastic Analysis
An analysis of deformations and internal forces based on
equilibrium, compatibility of strains, and assumed elastic behavior, and representing to a suitable approximation the three-dimensional action of the shell together with its auxiliary members.
419.3.7 The thickness of a shell and its reinforcement shall be proportioned for the required strength and serviceability, using either the strength design method of Section 408.2 . I or the alternate design method of Section 408 .2.2. 419.3.8 She\! instability shall be investiWlled and shown by
419.2.8 Inelastic Analysis An analysis of dcfornlJ~lions and internal forces based on equilibrium, nonlinear stress-strain relations for concrete and reinforcement, consideration of cracking and timedependent effects, and compatibility of strains. The analysis shall represent to a suitable approximation thrcedimensional action of the shell together with its auxiliary members. 419.2.9 Experimental Analysis An analysis procedure based on the measurement of deformations or strains, or both, of the structure or its model; experimental analysis is based on either elastic or inelastic behavior. 419.3 Analysis and Design 419.3.1 Elastic behavior shall be an accepted basis for determining internal forces and displacements of thin shells. This behavior shall be permitted to be established by computations based on an analysis of the uncracked concrete stmcture in which the material is assumed linearly clastic, homogeneous and isotropic. Poisson's ratio of concrete shall be permitted to be taken equal to zero . 419.3.2 Inclastic analysis shall be permitted to be used where it can be shown that such methods provide a safe basis for design.
design to be precluded. 419.3.9 Auxiliary members shaH be designed according to the applicable provisions of this code. It shall be pennittcd to assume that a portion of the shell equal to the flange width, as specified in Section 408.13, acts with the auxiliary member. In sLlch portions of the shell, the reinforcement perpendicular to the auxiliary" member shall be at least equal to that required for the flange of a T-beam by Section 408_13.5. 419.3.10 Strength design of shell slabs for membrane and bending forces shall be based on the distribution of stresses and strains as determined from either elastic or an inelastic analysis . 419.3.11 In a region where membrane cracking is predicted, the nominal compressive strength parallel to the cracks shall be taken as 0.4(". 419.4 Design strength of Materials 419.4.1 Specified compressive strength o/" conere!etc at 2g days shall not be less than 21 MPa . 419.4.2 Specifled yicld strength o/" nonprestressed reinforcclllcrH./;. shall not exceed 415 MFa. 419.5 Shell Reinforcement
419.3.3 Equilibrium checks of internal resistances and external loads shall be made to ensure consistency of results. 4]9.3.4 Experimental or numerical analysis procedures shall be permitted where it can be shown that such procedures provide a safe basis for design . 419.3.5 Approxi mate methods of anal ysis shall be permitted where it can be shown that such methods provide a safe basis for design . 419.3.6 In prestressed shells, the analysis shaH also consider behavior under loads induced during prestressing, at cracking load and at factored load. Where prestressing tendons arc draped within a shell, design shall take into account force components on the she!! resulting from the tendon profile not lying in one plane.
419.5.1 Shell reinforcement shall be provided to resist tensile stresses frolll internal membrane /"{)rL'c~;. to resi ~~ ~ tension from bending and twisting mOllle );: s, iu control shrinkage and temperature cracking and as special reinforcement as shell bOllndaries, load a!lachnll"llts ;11,;1 shell openings. 419.5.2 Tensile reinforcement s!lalJ be provided in two or more directions and shall be proportioned Sl !("!; that it,: resistance in any direction equals or exceeds the component of internal forces in that dircction .
Alternatively, reinforcement for the mell1br;!i .'
i it .('
slab shall bc calculated as thc reinforcCI11C,i! )
resist axial tensile forces plus the. tensile fI~ : friction required to transfer shear across ;.~ j<,
Association of Structural Engineers of tho r.)!iilipPllles
u ~ •.'
;11 the. til .. . :;, ; , .:
CHAPTEH 4 .- SIrUCIUral Concrete
4·11t
of thc membrane. The asslimcd coefficient of friction. fl. shall not exceed that specified in Section 411.8.4.3.
that the minimum development Icngth shalll>e 1.2/d hut not less than 500 mm.
419.5.3 The area of shell relnforcemelll ,II
Splice developmenl lenglhs of shell 419.5.12 reinforcement shall be governed by the provisions of Section 412, except thaI the minimum splice length of tension bars shall be 1.2 limcs the value required by Sectioll 412 but nol less than 500 Illm . The !lumber of splices in principal tensile reinforcement shi.lll be kept to a practical minimum. Where splices arc nccessary. lhey shall be staggered at least Id with not mord than onc-third of the rcinforccment spliced at any section.
419.5.4 Reinforcemellt for shear and bending moments about nxes in the plane of the shell slab shall be calculated in accordn~l{'e with Sections 410. 41 I and 413. 419.5.5 The area of shell tension reinforce ment shillJ be limited so tll3.1 the reinforcement will yield before either crushing of concrete in compression or shell buckling can lake place. 419.5.6 In regions of high tension, membrane reinforcement shall, if practical. be placed in the general directions of the principal tcnsilc IllCll1br
419.6 Construction
419.6. 1 \Vhc ll removHI of fonnwork is based on a specific modulus of elasticity of concrete because of stability or denection considermions. the value of the modulus of elasticity E(. shall be detennined from ncxural tCSIS of fieldclired beam specimens. The Il umbe r of teSI specimens. the dimcnsions of lest beam $pecimens .md test procedures sha ll be specified by the engi neer-of-record. 41 9.6.2 Tile lolerances
ror
Ille shape
or ll1e
shell shall be
spl.!cificcl. If construction res ults in deviations from the
shape greater than the specified to lerances. an analys is of the effect of the deviations shall be made and any required remedia l aCl i ons shall be taken to ens ure safe behavior.
419.5.9 Reinforccmcllt required to resist shell bending moment s shall be proportioned with due regard to Ihe
simultaneolls action of membrane ax ial forces al the Sil lllC location. Where shell reinforcement is required in only one face to resist bending moments. equal amOUJlts shall be placed near both surfaces of Ihe shell even though a reversal of bending moments is not indicated by thc an.tlysis. 419.5.10 Shell reinforccmelH in
419.5.1 I Shell reinforcement at the jUllction oj' the shell and slipporling members or edgc members shall be anchored in or extended through sudl memhers in accordancc wi th the requireme nls of Sc<.:l ioll 4 I 2, excep t N;)\lonal Structural Code of l11H PI1ilippines
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[clition Volum e 1
4.112
CHAPTEr~ 4 --
SIr'UClural Concrete
420.3 Dcterminati on of Hcquircd Dimensions a nd Material Properti es 420.3.1 Dimensions or the struc tural clcmcnts shall be established at critical sections .
420.1 Nol ations D = dead loads or rcl.Hed inlemaJ moments and forces 1'.. = specified compressive strength concrete. MP" " = overall thickness of member in the direction of action considered. mm :: li ve loads or related internal moments and forces :: span of member under load tcst, mm. (The shorter I, the span for (wo-way slab systems.) Span is smaller of (I) distance between centers of su pports Il nd (2) clear distance between supports plus th ickness II of member. In Eq. 420-1. span for a ca ntilever sha ll be taken as twice the disl.lncc from support to canl ilcver end 6"w.~ = measured ma ximum dcOec tion. 111111 . Sec Eq . 420I
D.''''(I> = measured resid ual defl ec tion. mill. Sec Eqs. 420-2
and 420-3 6,m/l.i :: max ilJ")urn dcOection meas ured du ring th e second tes t relative 10 the posit io n of th e strllctu re at the
beginning of the second test.
Illlll .
See Eq. 420-3
420.2 Strength Evaluatioll-Gcneral 420.2. 1 I r there is a doubt t h~ l .1 P;U1 Of all of a Slnlcture rneets the safety requircments of this code, a strength cv,IiUCl tioll shall he cCl ITicd out liS required hy the engineerof-record or building official. 420.2.2 If the effect or the strength deficiency is well und erstood and if it is feasible to measure the dimcnsions and material properties required for analysis. annlylical ev'llualions of strength based 011 those mcasurelllelllS shall suffice. RC4uired data shall bc determined in accordance with Section 420.3. 420.2.3 If the effect of the strength deficiency is not well understood or if it is Hot feasible 10 es tablish the required dimensions and material properties by measuremellt, a load test shall he required if the struclUre. is lO remain in service.
420.3.2 Locations and siz.es of the rcinforcing b'lI'S. welded wire rabric or tendons shall be determined by IllC.lsurcmcm. It sh~ 1I be permitted to base reinforcemcnt k .::
Compression-controlled sections, as definn J in Section 410.4.3: Mcmbers wilh spiral reinforcement ,:onl
Other reinforced members ...•..... . Shear and/or torsion Bearing 011 concrete ... _. . . . .. . • . . . . • . . . . . . . . . .
t.
'! ~'n
420.4 Load Tcst Procedure 420.4. 1 Load Arrangement
420.2.4 If the doubt ahout safety or it pallOr :111 of a structure involves deterioratioll il nd if the ohserved response during (he 10;1(..1 test satisfies the :lcccpt ancc criteria, the structure or part of the stfllcturC shal l be permitted (0 remai n in !-icrvicc for
The number and arrangement of spans or p::nds I{)(It\1
sh
Association of Stwctural [: nglneers of t l H~ PI1ilipPIfles
II I
CHAPTER 4 - S truct ural Concrete
420.4.2 Load Inlensily nle IOlal lesl load (incl uding dead load already in place) shall nol be less Ihan Ihe larger of ( I), (2), and (3):
I.
1.15D + I.5L + O.4(L,or R)
2.
1.1 5D + 0.9L + I.5(L, or R)
3.
IJD
4· 1 :3
420.6.2 Meas ured maximum de fl ect ions shall satisfy onc of the following condit ions: 2
I!. < I, , - 20,000"
(420- 1)
(420-2)
The load faclor on Ihe Ii ve load Lin. (2) shall
b'i. p.ennilled
to be reduced to 0.45 except for garages, areas ' occupie~ :as
places of public assembly. and all Meas. where L is greater 2 than 4.8 kN/m . II shall be permitted to reduce L in accordance with the provisions of the applicable code .
420.4.3 A load tcst shall not be made until Ihat portion of the structure to be subject to load is at least 56 days old . If
If the measured maximum and residual denections, ~I and I!., , do not sat isfy Eq. 420-1 or 420-2, it shall be permitted [0 repeat the load test.
•
The repeal lest shall be conducted not earlier than 72 hours afte r removal of th e first tes t load. The pOL1ion of (Ile stnlcture tested in the repeat test shall be considered accept able if defl ec ti o n recovery sa tisfied the conditiun:
the owner of the Slnlcture, the cont ractor, and all involved parties agree, it sha ll be pCfll1iH Cd to make Ihe test at an
I!.
earlier age. 420.5 Loading Crileria 420.5.1 The initial value for all applicable respon se measuremenls (such as deflecti on, rotation, strain, ~ Iip , crack widths) shall be obtained nOl more th an one hour before application of the first load increment. Meas urements shall be made at locations where maximum response is expected. Additional mcasurements shall be made ifrcquircd .
, -<~ 5
(420-3)
where ..1; is the maximulll deflection measured during the second test relative 10 the posit ion of the stru cture at (he beginning of th e seco nd tesl. 420.6.3 Stl1Jctural members tested shall not have cracks indicating the imminence of shear failure.
420.5.2 Test load shall be applied in not less than four approximately equal in cre ments.
420.6.4 In regions of structural members without tran sverse reinforcement. appearance of stru ctural cracks inclined (0 the longi tud inal axis and having a hori zontal projection longer th an the depth o f the member at mid-point of the crack shall be cvalu
420.5.3 Un iform tcst load s hall be applied ill a ma nner to ensure uniform distribution of (he load lransmiucd to the Structure or portion of the stru cturc being tested. Arching of the applied load shall be avoided.
420.6.5 In regions of anchorage and lap spli ces, the appearance along the line of reinforcement o f II series of short inclined cracks or horizontal cnlcks sh:ill be evaluated.
420.5.4 A set of response measureme nts shall be made after each load increment is appli ed and after the total load has been app li ed all the structure for at least 24 hours.
420.7 Provisions for Lower Load Rliling
420.5.5 TOlal lest load s hall be removed immediately aner all response measurements defined in Section 420.5.4 arc made. 420.5.6 /\ sc t of [in al response measurements shall he made 24 hours nfter the test load is remo ved.
If the s tructure under in vestigation does not satisfy conditions or criteria of Sections 420.2.2, 420.6.2 or 420.6.3, the slnlcture may be permi lled for usc aI a lower load rating based 011 the results of the load test or analysis, if approved by the building offici'll. 420.8 Safety
420.8. 1 Lo;\d tests s hal! be cond ucted in stich a mann er as to provide for sa fet y o f lire
420.6 Acceptance Crit eria 420.6.1 The pOl1ion of the structure tested 5h;.111 show nc) evidence of fai lu re. Spalling Clnd crushing of com pressed concrete shall he considered all ind icat ion of failu re .
420.8.2 No safely IllC.ISUrC$ s hall interfere with load test procedures or affect rcsulls. ' . .' ., . .j '
.
~
" J
...
..
,
111
Nalional Structural Code of the Philippines 6 [(!ition Volume 1
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CHAPTER 4 - Structural Concrete
h ..,
1,/ 1,111
421.1 Notations ::;
cross~sec(io n al
area
of
a st ructural
member
• measured out-lo-out o f transverse rei nforcement, mOl
2
::; area o f concrete section, resistin g shear. of. an individ ual pier or horizofual wall segment , 111m2 :::; gross area of concrete section bounded by web thickness and length of section ill the direction of shear force considered, 111m2
A"I'
I, I"
M,
::; gross area of section, 111m2 ::;; effecti ve cross-secti onal area within a joint (see Section 421.7.4_1) ill a pl ane parallel to plane of 2 rcinforccmcllI ge nerating shear in the joint. mm . The joint depth shall be the overall depth of the column . Where a beam frames into a suppOI1 of larger width, the effective width of the joint shall not exceed the smaller of:
II,. A,,",
b
b ... e
/"
[f.
t, 1,.
I.
Beam width pJU$ the joint depth; or
2.
Twice the smaller perpendicular di stance from the longilUdin al axi s of the beam to the co lu mn side. Sec Section 42 J .7.4.1.
;:: tOlal cross-sectional area of transverse rein forcement (i ncluding cross lies) withi n spacing, s. and perpendicular ro dimension , 11(, mm 1 ;:: lotal area of reinforcement in each grou p of diago nal bars in a diagonally rein forced coupling bea m. 111m 2 ::;: effective co mpressive flan ge width o f a structu ra l membe r, mm = web wid th, or diameter of circular secti o n, mill ;:: di stance from the extreme compression fiber to neutral
M,
M,
M. s
s,
,\'r
v,
:=
v"
v"
= height of ent ire wall or of the .segment of wall considered, mill = maximum ho rizontal spacing of hoop or cross tic legs on all faces of Ihe colllmn , mm = de velo pmcnt length fo r a straight bar = deve lopmcnt length for a bar with a standard ho~k as defi ned ill EG- 421 -6, mm = c lear span measured face-to-face of Sll PPOflS , mm = minimum length , measured fro m joinl face alon g axi s of s tru ctuntl member. over whi ch trans It: '-Sl!reinforcement must be prov ided, mOl == lenglh of enlire wall or of segmen t of wail considered in direction of shear force, mm = moment at the face of the joint, corresponding It) the nominal flexural strength of the colum ,': framing int o (hat joi nt , calculated for the factored axia.l force, consistellt wit h the direction of the lateral fo rces considered, resulting in (he lowest nexural s trength , see Scction 421.5_2.2 == moment at the face of the joint. corresponding to the nominal nexural st rength of the girder including slab where in ten sion, framing inro that joint. see Section 421 .5_2.2 = probable ncxuraJ stre ngt h of members, with or without axial load. det ermined using th e properties of the member at the joint faces assuming a tensile strength in the longitudinal bars of at least 1.25.0. and a stren gt h-reduction fac tor ¢of 1.0 ::: portion of s lab moment balanced by SUppOJ1 moment = factored moment at secti on == spacing of longitudinal reinforcemen t, transverse
reinforcement. prestressing tendons, wi res, or anch ors. 111111, Sections 410 to 412. 417 to 421, and 423 ::: moment , shear or axial force 1 mOl, Section 421 == longitudinal spacing of Inlllsverse reinforcement withillthe length I... nun :;:: nomin al sheilr strength provid ed by concrete. Sections 408, 411. 413 and 421 = design shear force corresponding to the development of the probable moment s trength of (he memher, sec Sections 421.5.4 . 1 or 421.6.5.1 == nomin al shea r strengt h. Sec tions 408, 41 0, 411. 421,422 and 423 ::: factored shear force .11 secti on, Secti ons 41 J h) 413,417 .42 1 alld 422
Association o f Stru ctural Engineers o f tile Ph ili ppi nes
CHAPTER 4 - Structural Concrete
a a;.
: : : angle defining the orientation of rcinforcC Il1CIll, Sections 411. 421 and 427 : : : coeffi cient defi ni ng the relative cont ribut ion of
4 -1 15
hoo ks of two successive cross ties e ngaging the same longi tudinaJ bars shall be ahemated end for end.
concre te sirength 10 nomin:11 wall strength , Sec
DESIGN DISPLACEMENT. Total lateral displacement
Equation 42 1-7.
ex pected fo r the desig n-basis ea l1hqu ake, as required by Ihe governin g code for earthqu ake-res istant design.
4.
::::: des ign di splaceme nt, mm , Sectio n 42 1
p
= rati o of nonprcstrcsscd tension reinforcement = A/ (/>"). Secti ons 411. 41 3. 421 and 425 .
DESIGN LOAD COMBINATIONS. Combinati ons of
:::::
fa ctored loads and forces specified in Section 409 .3.
ratio of area of distributed longitudinal reinforce ment (0 gross concrete area
pC'1)cndicllinr to th at reinforcement, Sectio ns 4 1 J, 414 and 42 1 PI = r.ali o o f area of d istributed transverse rcinforccmCnllO gross concrete area perpcndi cuJar (0 th aI reinfo rcement, Secti ons 4 1/. 414 and 421
p,
P.·
::::: rati o of yo lume of spiral reinforceme nt to to lal volu me of core co nfined by the spiral rc inforccmcllI (measured oul-(Q-Qu t of spirals) ::::: ratio of area of distributed reinforcement perpendicular lO the plane o f An to gross concrete area A f~ = stren gt h-reduction factor
DETAILED
PLAIN
CONCRETE
STRUCTURAL
WALL. A wall co mpl yi ng with the requircn~e nts of Secti on 422 . including Section 422 .7.
DEVELOPMENT LENGTH FOR A BAR WITH A STANDARD HOOK. The shonest distance between the crit ical section (where the sirengt h o f the bar is to be develo ped) and a tangent to the ou ler edge of the 90-degrce
hook. DRY CONNECTION. A connection used between precast me m bers whic h does not q ualify as a wet connec tio n.
FACTORED LOADS AND FORCES . Loads and fo rces 421.2 Definitions
modified by the factors in Section 409.3.
BASE OF STRUCTURE. Level at whi ch eaJ1hquake motion s are ass umed to be- imparted to a building. Thi s
I·IOOP. A closed ti c or continuously wound tic. A closed tic can be made up of severa l reinforcin g c lem e nts, each
le ve l d oes not necessari ly coinc id e w ith th e grou nd leve l.
hav in g seismi c hooks at bot h ends. A co nt inuously wou nd lie s ha ll have a seismi c hook a t bo th ends_
BOUNDARY ELEMENTS. Portions along " ructu ral wall and sl niclural d i
COLLECTOR ELEMENTS. Ele men t' thai ,erve 10 transmit the incrti a l fo rces within structural diaphragms to members of the lateral-foree-resisting syste ms.
CONFINED CORE. The area within the co re defined by h,..
CONNECTION . An clemenl that joins two precast members or a precast mc mber an d a c asi -in-place me mber.
COUPLING UEAM . A horizonlal clement in plane with and cOllllecting two she;lr walls. C ROSSTIE. A COlll ill llOliS rein forci ng bilr havi ng a se is mi c hook a l o ne e nd a nd H hook o( nO I less th illl 90 degrees wilh at leas t six-d iamete r ex tens ion a t the o ther e nd . The hooks sha ll e ngage peri pheral longitud ina l bilrs . The 90-dcg rcc
JOINT. The geometric vo lume common to illlcrsecling membe rs.
LAT ERAL FORC E RESISTI. G SYSTEM. That ponion of the struct ure co mposed of mem be rs propoJ1ioned to resist forces related to cm11lqua kc e ffec ts.
LIGHTWEIGHT-AGGREGATE
CONCRETE.
AII -
li g htw eight or sand -li ght weight aggregate co nc rete made with lightweight aggregates cO llfonning to Sec ti o n 403.4 .
MOMENT FRAME. Space frames in which mem bers and j oi nts res ist forces th rough ncx ure, shear, a nd, axial force. . Mo me nt fr am es shall be categorized as fo ll ows: INTERMEDIATE MOM ENT FRAME. A cast-in-place frame complyin g w ith the requirements of Section 42 1. 12.
ORI>INARY MOMENT "RAMK IX cast-in-place or precnst concrete frame. complying wit h the requiremcnts of Sections 40 1 through 418. a nd in the case of ordi nary moment fra mcs ass ig ned to seismic zone 2, also complying wit h 42 1.1 4 .
National S iru ctural Code of th e PI)ilippin es 6
th
Edition Volu me 1
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CHAPTER 4 - Struclural Concrele
SI'ECIAL MOMENT FRAME. A cast-in -place frame complying with the require ment s of Sections 421.3.3 through 421.3 .7, 421.5 throu gh 42 1.7, or a pre"aS! frame
ORDINARY
STRUCTURAL
PLAIN
CO NOWT ;.:
WALL. A wall complying with the requiremen ts of Sec ti on
422, excluding Sec tion 422.7.
complying with the requirements of Secti ons 421.3.3 the req ui rement s for o rdinary mo me nt frames s hall be
ORDINARY REINFORCED CON C',m Tfi STlWCTURAL WALLS. A wall cOll1pl yi ng w,' h the
s ati sfied .
requirements of Sections 40 1 thro ugh 418.
NONLIN EAR ACTION LOCATION . Th e ce llter o f the region of yielding in Ilexufc, shcm o r axial action .
INTE RMEDIATE I'RECAST STRUCTURAL ' -"ALL . A wall complying with all applicab le requil clllt" .1 s or Sect ions 401 through 418 in additi on to 42 1.4.
through 421.3.7, 42 1.5 throu gh 421.7, 421.1 3. III addition,
NONLINEAR ACTION REGION . The member le ngth
over which nonlinear action takes place. It shall be taken as extendi ng a distance of no less than 1112 on either s ide of the nonlinear action locati on.
SPECIAL STRUCTURAL WALL. 1\ cas t-'''-pb" ,·. " .. precast wall complying with the requi rements d .<~ ····1io 421.3.3 through 421.3.7, 421. 8 and 421.15, as "pi;lie "!"., ;' .
SEISMIC 1·100K. A hook on a Slirl1lp, hoop o r crosS!ie
addit ion to the requiremen ts for concrete structural walls.
ha vin g a bend not less [han 135 deg rees . except tlh'll circular hoops s hall have a be nd no t Jess th an 90 degree s. Hoo ks s hall have a six-di ameter (but n OI less than 75 mill), ex tension Ihal en gages the longi tudinal reinforcement and projects into the interior of {he stirrup o r hoop.
SHELL CONCnETE. Concrete outside th e tra nsverse rei nforcement confining the con crete. SPECIAL BOUNDARY ELEMENTS. 1loundary c lemctll s required by Sections 42 1.8.6 .3 or 42 1.8.6.4 . SPECIFI ED
LATERAL
FORCES.
Lateral
forces
corres ponding to the appropriate di stributi on of lhe des ign base shear force prescribed by the governing code for
eart hq uake-resistant design. STRONG CONNECTION, 1\ con nection th at remains e la stic. while the designated nonlinear acti oll regions undergo inelasti c response under the Design I3i1si s Ground Mot ion . STRUCTURAL DIAPHRAGMS. Structural members, such
Ooor and roof slabs. lhat tran s mit inertial forces HCling in the plane of th e member to the vertical ele:ments of the seismic-foree-resisti ng sys tem. :'IS
STRUCTURAL TRUSS. I\ssemblage of reinforced co ncrete members s ubjected primarily to axial forces. STRUCTURAL WALLS. Walls proportioned to res ist combiniltions of shears, mo men t. and axial fo rces induced by earlhquake mo tion s. A s hear wed l is a struc tural wall. Stru ctuftll wall s s hall be c.alegori zcd as foll o ws:
ordi nary rc in!"orced
STRUT. An clement of a structural diaphragH ' u·.·· ! prov ide cOIH inui! y around an opening in lhe diap!iJ;lt;·
Itl
TrE ELEMENTS. Elements that serve
to trm lSllIi r I :::nia forces and prevent separation of building cornpO!:wh ;inch as foo lings and walls.
WALL PIER. A wall segmen t with a hori w ll t3[ ;, I?n, ~ thickness ratio between 2.5 a nd 6, and whose cl t:ili l~ c j r ~ i:: ;,' at leas t two ti mes its horizonlal length.
W ET CONNECTION. Uses an y of the "dici ng I, ,,'ti,,,,:o. to
connect precnst members and uses ca s t-in-pl at:e
(;(l!Il'n!.h.~
or grou t to fill the s plicing closure. see Sections 4 2J .'; 42 1.1 3.
Of
421.3 General Requirements 421.3.1 Scope 42 1.3.1.1 Section 4 2 1 contain s s pecial rcq uin:u){'},;': io~ design and construc ti o n of reinforced COl1 cn:h 11\ ;;1:' •. :; t l: a structure for w hich the design force:;. rda!'. ~ i 10 earthquake mOli ons. have been determined nn ill· h.,,; , ~.,. energy d issipal ion ill the nonlincar range of H.'!".PIW .
421.3.1.2 All structures shall he assigned to a :-;ch,lJ'J ic in accordance with Section 401.1 .8. 1 .
,:OIlC
42L1.1.3 A ll members shall sati s fy n-q nirrn: n:!:. o f Sections 401 to 419 a nd 422. S tructures :lssi !.: ::l" · !' .. , L,:,' zo nes 4. or 2 :-;hall al so sat is fy Scction s 4 2! : . . ,: iL!,.:.,t'.!·; 42 1.3 .1.7 as appli cable.
Association of Structural En gineers of the Philipp ines
CHAPT ER 4 - Structural Co ncrete
421.3.1.4 Structures assigned to seism ic zone 2 shall satisfy Sections 421.J.1 .2 and 421.3.1.7. 421.3.1.5 SlruclUrcs ass igned to seism ic zone 4 s hall satisfy Sections 421.3. 1.2 through 421. 3. 1.7 and 421.9. 421.10. and 421. 1 I.
421.3.1.6 A reinforced concrete stru ctural system not satisfying Il1c - reCJuirements of this Section shall be pcnnillcd if it is demonst rated by expcrimclHal evidence and analysis thaI the proposed sys tem w1J[ have strength and lOughncss equal to or exceeding those provided by a comparable monolithic reinforced co ncrete structure satisfyin g this Secli <> l1.
4· t t 7
421.3.4.3 Speci fied compressive strength of lightweight
concrct c,!c' , shall not exceed 35 MPa unless demonstrated by experimental evidence that structural members made wi th that lightweight concrete provide strength and toughness equal to or exceeding those of comparable members made with normal weight concrete of the same strengLh . Modificalion factor 1 for Iightwciglu concretc in thi s Secti on shaH be in accordance with Section 408.7. ( unless specificall y noted o thclwi se.
421.3.5 Rei nforcement in Special Moment Fram es and Special Structural Walls 421.3.5.1 Requirements of 421.3.5 apply to special' moment
frames and special structural walls and coupling beams. 421.3.2 Analysis and Proportioning of Structural
)
Members
1
421.3.2.1 The interaction of all st ru ctural and nOllsi l1lctural members wh ich ntmcriall y affec l the linear and Ilonlincaf
I,
response of the Sll1Icturc LO earthqu ake motions shall be co nsidered in the analysis.
;
421.3.2.2 Rigid mcmbers assum ed not to be a part of th e latera1-forcc resisting system shall be permitted, provided their effect on the response of the s.ys tem is considered and accommooated in the stnlclural design . Consequences of fflilure of sll1JcltJr
Strength reduction faclO!'s shall be as given in Section 409.4.4.
421.3.4 Concrete in Speci ~11 '''loment Frames and Special Structural Walls
42J .3A.l Req uiremcnts of Section 421 J.4 apply to speci al 1ll0lllCI1l fnlln cs and s pecia l struc tural walls and coupling beams. 421.3.4.2 Compressive ~ t rcllg (h .f'.. shall be no! less (han 21 MPa.
421.3.5.2 Defomled reinforcement resisting earthquakcinduced flexu ral and axial forces in frame members. structural walls, and co upling beams, shall comply with ASTM A 706M. ASTM A615M Grades 280 and 420
reinforcement shtllJ be penni tied in these members if: I.
The aClUal yield stre ngth based on mill tests does not
exceed the specified yield strength by more than 125 MPa ; and 2.
The ratio Of(l hc actual ullimatc tcnsile strength 10 the actu al tensil e yield strength is 110t less than 1.25.
421.3.5.3 Prestressing steel resisting eart hquake-induced flexural and axi al loads in fram e mem bers and in precast stru ct ura l walls shall compl y with ASTM A416M or A722M .
421.3.5.4 T he va lue of 1;., used to compu te Ihe amount of co nfinem ent reinforccmelll shall not exceed 700 MPa. 421.3.5.5 The value of f y or h'l used in design of shea r reinforcement sh
421.3.6.1 Mechanical splices shall be classified as either Type 1 or Type 2 mechanical splices. as fo llows: Type J Splice. Mechan ical splices shaH co nform to Section 4 12. 15.3 .2: Type 2 S pli ce. Mecha nical splices shall conform to Secti on 4 I 2. 15.3.2
of the spliced bar.
th
National Slructural Code of the Philippines 6 Ed ition Volume 1
4-118
CHAPTEF14 -- Structural Concrete
421.3.6.2 Type 1 mechanical splices shall not be used
within a distance equal to twice the member depth from the column or beam face for special moment frames or from sections where yielding of the reinforcement is likely to
421.5.1.3 Width of member b". shall not be less than the smaller of 0.311 and 250 ml11.
occur as a result of inelastic lateral displacements. Type 2
421.5.1.4 The width of member shall not exceed the \',!idth of the supporting member, C2 plus a distance on each side of thc supporting member equal to the smaller of (I) and (2):
mechanical splices shaH
I.
Width of supporting mcmber,
2.
0.75 times the overa!! dimension of sLJppOiting member, CI.
be permitted to be used at any
C2,
and
location.
421.3.7 Welded Splices in Special Moment Frames and Special Strnctural Walls 421.5.2 Longitudinal Reinforcement
421.3.7.1 Welded splices in reinforcement resisting earthquake-induced forces shaH conform to Section 412.15.3.4 and shall not be used within a distance equal to twice the member depth from the column or beam face for
special moment frames or from sections where yielding of the reinforcement is likely to occur as a result of inelastic lateral displacements. 421.3.7.2 Welding of stimJps, tics, inserts or other similar elements to longitudinal reinforcement required by design shall not be permitted. 421.4 Intermediate Precast Structural Walls 421.4.1 Seape
Requirements of Section 421.4 apply to intermediate precast structural walls forming part of the seismic-forceresisting system. 421.4.2 In connections between wall panels, or between wal! panels and the foundation, yielding shall be restricted to steel clements or reinforcement.
421.5.2.1 At any section of a flexural member, except provided in Section 410.6.3, for top as well as for bOllo; reinforcement, the amount of reinforcement shall not h, less than that given by Eg. 410-3 but not less than I Ab"ti/i and the reinforcement ratio, p, shaH not exceed 0.025. /.' least two bars shall be provided continuously both top aI' " bottom. 421.5.2.2 Positive-moment strength at joint face shall nc be less than one half of the negative-moment strengt! : provided at that face of the joint. Neither the negative n, the positive-moment strength at any section along men:', length shall be less than one fourth the maximum mon!c;c( strength provided at face of either joint 421.5.2.3 Lap splices of flexural reinforcement shall be permitted only if hoop or spiral reinforcement is proVii:: (; over thc lap length. Maximum spacing of the tranSV(', j reinforcement enclosing the lapped bars shall not exceL,; d!4 or 100 mm. Lap splices shall not be used: I.
Within the joints;
2.
Within a distance of twice the member depth from Ihe face of the joint; and
421.4.3 Elements of the connection that are not designed to yield shall develop at least 1.5S,.
3.
At locations where analysis indicates Ocxural yirldin;'. caused by inelastic lateral displacements of the frame.
421.5 Flexural Members of Special Moment Frames
421.5.2.4 Mechanical splices shall conform to Secli(i), 421.3.6 and welded splices shall conform to SCClHJil 4213_7.
421.5.1 Scope
Requirements of Section 421.5 apply to special moment frame members that form part of the scismic-force-rc 0 isting system and arc proportioned primarily to resist flexure. These frame members shall also satisfy the following conditions; 421.5.1.1 Factored axial compressive force on the meillber, P shall110t exceed (A,J/IO). II ,
21.5.2.5 Prestressing, where used, shall sati ,'J,;' i I through (4), unless used in a special moment frame ;;::; permitted by Section 421.8.3: I.
The average prestress, .I;"., calculated for an arca ( to the smallest cross-sectional dimension or [i l (', member multiplied by the perpcndicular cro.\~;":: ' >: ;;," dimension shall not exceed the smaller or 3.5 1\-) i';i Hii\; /' 110.
421.5.1.2 Clear span for the members, /", sha!1 not be less than fOllr times its crfectivc depth. Association of Stru(;tural Engineers of the Philippines
CHAPTER 4 - Structural Concrete
2.
Prestressing steel shall be unbonded in potential plastic hinge regions. and the calculated strains ill prestressing sieel under the design displacement shall be less than I percent
3.
Prestressing steel shall 1101 contribute 10 more than oneqU<111er of (he posi (i ve or negative flexura l si rength at the criti cal section in a plastic hin ge region and shall be anchored at or beyond the exterior face of (he joint.
4.
Anchorages of the post-tensioning tendons resisting cl.lrthquakc-indllced forces shall be capab lc of aJlow ing tendons 10 wit hstand 50 cycles of loadi ng. bounded by 40 and 85 percent of the speci fied tensile' strength of Ihe prestressing steel.
421.5.3 Transverse Reinforcement 421.5.3.1 I'loops shall be provided in the following regions frame members:
of
I.
Over a length equal to twice the member depth measured rrom th e race or the supporting member toward midspan, at both ends of (he tl exural member;
2.
Over lengths equa l to twice the membe r depth on both sides of a section where flcxural yielding is likely to occur in connection with inelastic latcral disp lacements of the frame.
421.5.3.2 The first hoop shall be located not more than 50 mill from the face of a supporti ng member. Maximulll
4·119
shall have their 90~degree hook.1.i at opposite sides of th e flexural member. If the longitudinal reinrorcing bars secured by the crosslies arc confined by a slab on only one s;ide of the flexural frame member, the 90-degree hooks of the crossti es shaJI all be placed on that side. 421.5.4 Shear Strength Requirements 421.5.4.1 Design Forces The design shear forces V,. shall be determ ined from consideration of the static forces on th~ portion of the member between faces of the joint. It shalt bc assumed that momcnts of opposite sign corresponding to prob;'lble flexural strength Mpr act at lhe joint faces and that the member is loaded with the tributary gravity load along its span .
421.5.4.2 Transverse Reinforcement Transverse reinforcement over the lengths identified in Secl ion 421.5.3.1 shall be propol1ioncd to resist shear assuming V... :>:: 0 when both of the following conditions occur: 1. The earthquake-induced shear force calculated in accordance with Secti on 421.5.4.1 represents onchalf or more of tile max imum required shear strength within those lengths; 2.
The
factored
axial compressive force
eart hquake effects is less than
incl udi ng
AJ·J20.
spacing of thc hoops shallno{ exceed : I.
2.
d /4 ; Eight
limes thc di alllci er of lhe smallest longi tudina l
421.6 Special Moment Fr:une SUbjected to Bending a nd Axia l Load
bars; 3.
4.
24 times the di.lllletcr of the hoop bars: and
300
421.6.1 Scope The requirements of Section 42 1.6 apply to special moment
111m.
421.5.3.3 Wh ere hoops arc required, longitudinal bars on the perimeter shall have lateral support co nfo rming to Section 407. 11 .5.3.
frame members that rorm pan of the seismic-foree-resisting systeJll and that resist a factored axia l compressive force PII under any load combination exceeding AJ/ IJ O. These rrame members shall also satisfy the conditions of Sections 421.6.1. 1 and 421.6 .1.2.
421.5.3.4 Where hoops arc not required , sti rrups wit h seism ic hooks at both ends shall be spaced at a distallce not more than tll2 throughout Ille length or the member.
421.6.1.1 The short cst cros!Hicctional dimensi on, measured strai ght line passing through the geometric ccnt~~i.d, shall not be less (ban 300 mOl. .
42],5.3.5 Stirrups or ti c.Ii required ({) fcs ist sheilI' shall bc hoops ove r lengths of members il S specified in Sections 42 1.5.3.1.
421.6.1.2 The ratio of the shortest cross-sec tional dimension 10 the perpendicular dimension shall not be less
011 II
Ihan 0.4.
421.5.3.6 I-loops in Oex ur:11 members shall be permitted to be made lip or two pieces of rei nforcement: a stirrup having seismic hooks at both ends and closed by a crosslic. Co nsecutive crossties engaging the same longitudinal har th
National Structura l Code of the Philippines 6 Edition Volum a 1
CHAPTER 4 ~ Structural Concrete
4-120
421.6.2 Minimum Flexural Strength of Columns
421.6.4 Transverse Reinforcement
421.6.2.1 Flexural strength of any column shall satisfy
421.6.4.1 Transverse reinforcement as required in
Section 421.6.2.2 or 421.6.2.3.
421.6.4.2 through 421.6.4.4 shall be provided ov,,'" 10 from each joint face and on both sides of allY .'-;('.r' 'In where flexural yielding is likely to occur as :\ i(~S!lj if inelastic lateral displacements of the frame. Length /0 c;L:tll not be less than the largest of (I). (2), and (3):
421.6.2.2 The flexural strengths of the columns shall satisfy Eq.421-1.
LM", " (6!5)LM"r,
(421-1)
where;
LM"c
= sum
of moments at the faces of the joint corresponding to the nominal flexural strength of the columns framing into that joint. Column flexural strength shall be calculated for
the factored axial force, consistent with the direction of the lateral forces considered, resulting
in the lowest flexural strength. .EM"" = sum of moments at the faces of the joint carfes ponding to the nominal flexural strengths of the girders framing into that joint. In T-bcam
construction, where the slab is in tension under moments at the face of the joint, slab reinforcement within an effective slab width defined in Section 408.11 shall be assumed to contribute to flexural strength, Mllb if the slab reinforcement is developed at the critical section for flexure. Flexural strengths shall be summed such that the column moments oppose the beam moments. Eq. 421-1 shall be satisfied for beam moments acting in both directions in the vertical plane of the frame considered. 421.6.2.3 If SectioJl 421.6.2.2 is not satisfied at a joint, the lateral strength and stiffness of the columns framing into that joint shall be ignored when determining the calculated strength and stiffness of the structure. These columns shall conform to Section 421.13. 421.6.3 Longitudinal Reinforcement
421.6.3.1 Area of longilUdinal reinforcement, be less than 0.01 Ag or more than 0.06 Ai."
A~I>
shall not
~"'er'
) " )S
". ·,,'h
I.
The depth of the member at the joint face {::;':H section where flexural yielding is likely to ()(,.'" .
2.
One-sixth of the clear span of the member; and
3.
450 mm.
~e
421.6.4.2 Transverse reinforcement shall be provided :)y either single or overlapping spirals satisfyi!ll' .'.;('.~ ,I,m 407.11.4, circular hoops, or rectilinear hOOf"~ :i!, Or without crossties. Crossties of the same or smal!:" :';,. I .C as the hoops shall be permitted. Each end of tll<' ; Tii" iir of rectilinear hoops, lin within a cross sccliu;
I.
One-quarter of the minimum member dirncnsiuli;
2·.
Six times the diameter of the smallest longiH!(Liiall, 'r; and
3.
s", as den ned by Eq. 421-2. s"~.IOO+
350~1r.) ( --'-3--
The value of Sf! shall not exceed 150 mill, and need not taken less than 100 rnm.
'~e
421.6.4.4 Amount of transverse reinforcement required
ill
(I) or (2) shall be provided unless a lar!V:i'
,.,
;::;" ,I liin
required by Section 421.6.5. 421.6.3.2 Mechanical splices shall conform to Section 421.3.6. J and welded splices shall conform to Section 421.3.7.1. Lap splices shall be permitted only within the center hall' of the member length, shall be designed as tension lap splices, and shall be enclosed within transversc reinforcemcnt conforming to Sections 42! .6.4.2 and 421.6.4.3.
I.
The volumetric ratio of spiral or ( i \, I:: reinforcement, P." shaH not be less than rcqllircd by ! 421-3:
P.
= O. I 2 f",. 1/;.,
and sha!ino( be less than required by 2.
{i::?l, L~q
The total cross-sectional area of reinforcement, A,,,, shall not be Jess tlv"
j-;,:; !(
l['
'(Ii
Eqs. 421-4 and 421-5.
A,,,
= 03 (s/J,(",I(,,) [(AlA,,,) .-
Association of Structural Engineers of Ole Philippines
IJ
..:\
CHAPTER 4 ·· Slr" cl " ral COnCrel"
A,." = O.09(.rb,.!',./f,.,)
(42 1-5)
42).6.4.5 JJeyond Ihe Icngl h I" speeiJied in Seelion 421.6.4. 1, the colullln shall contain spiral or hoop reinforcement salisfying Secti on 407. 10 wilh celller-IOccnler spacing. s, not exceedi ng the smaller of six tinllcs the diameter of the smallest longitudinal column bars and 150 mnl, unless
the joint. In no case shall Vt' he less til'1I1 .the fac tored shear determined by analysis of the s l!uctUrc. 421.6.5.2 Transverse reinforce ment over the length s 1//. identified in Section 42 1.6.4.1, shHII be propol1ioned to resist shear assuming VI" :;; 0 when both of the following conditions occur:
I.
The earthquake-induced shear force, calculated in accordance with Secti on 421.6.5. 1, represe nts onc- balf or mo re of the max imum requ ired shear strength within I,,;
2.
The factored ax ial co mpressive force, PII , including ca nhquake effeels is less Iha n A,t,120.
421.6.4.6 Columns supporting react ions from discOlllinucd stiff members. such as walls, shall satisfy (I) and (2): J.
Transverse rei nfo rcement as spec ified in Sectio ns 42 1.6.4.2 lilrollgh 42 1.6.4 .4 shall be provided over their full height beneath the le vel at whi ch the di scontinuity occurs if the factored axia l com p r,~ssivc force in these members, relmed to earthquake eCfect,
exceeds AJ·J IO. Where design forces have been magn ifi ed 10 aCColl nt for the over slrenglh of" the ven ical clements of the seismic-foree-resisting system , Ihe limi l of AI.: /I 0 ,baJJ be illcrea,ed 10 A"f.'/4. 2.
Transverse reinforcement sha!1 ex tend illto the di sco minllcd member at least Id the l:lrgesl longitudina l bar, where Id is determined ill accordance with Section 421.7.5. Where th e lower e nd of the colum n terminates on a wall , th e req uired tran sverse re inforcemcnt shaH ex tend into the wall il! . least Id of the larges t longitudinal column bar at the pain t of terminatioll . Where the column lerminHtcs on a footing or mat, the required tra nsve rse reinforcemcnt shall extend at least 300 Illm into the footing or mal.
4·121
421.7 Jointl) of Special Mom ent Frames 421.7.1 Scope
Requ irements of Section 42 1.7 npp ly to beam-column joints of" special moment frames formin g pan of the seismicforce~resisting systelll. 421.7.2 General Requirements 421.7.2.1 Forces in longitudinal beam reinforce ment at the joint face shall be determined by assu min g thaI the stress in the flexurallcns ile reinforceme nt is 1.251;.. 421.7.2.2 Beam longitudinal reinforcement terminated in a column shall be ex tend ed to the far face of the confined column co re and anchored in tension accordi ng to Seclion 42 J .7.5, and ill compression according to Section 4 J 2.
42) .6.4.7 If the concrete cover olll side the confi ning In.lllsversc reinrorce me nt specified in Sections 42 1.6.4 . 1. 421.6.4 .), and 421.6.4.0 exceeds 100 mm, add itiona l transvcrse reinron.:clllcnt shall be provided . Concretc ,cover for addi tional transverse rei nforcemen t shall not exceed 100 mill and SI)ac ing of additional transverse rein forcc:mcnt shall nOI exceed JO() 111m.
421.7.2.3 Where longi tud inal beam reinforcement ex ten ds through a beam-colulllll joint, the column dimensioll parallel to lhe beam reinforcement s hall not be less th an 20 ti mes [he diameter of the largest longilUd inal bar for normal weight concrete. For lightweight conc rete, the dimension shall not be less tha n 26 times the bar diameter.
421.6.5 Shear Strengt h Requirements
421.7.3 Transverse Reinforcement
421.(,.5. I Des ign Fun·cs The design shear force \I,. slwll be determilled from cons iderat ion or [he max imulll forces thil t CtIll be gCllcr,lIed at the faces of the joints al eac h e nd of the memher. T hese j oint forces shall be determined using ·th e lllilxillltlHl probab le moment strengths Ml'n at each end of the llle mber associated wi th the range of facto red axial loads, PII, acti ng on the member. The member shears need nOI exceed r. hose det ermined from joint st rength s based on the probab le mom e nt strength Mill of the transverse members rramil1g in
421.7.3.1 Join t (ransverse rci nfmcemen t sh~11I satisry either Seclion 42 1.6.4.4( I) or 421.6.4.4(2), and , haJJ also sali,fy Seclions 421.6.4 .2. 42 1.6.4 .3, and 421.6.4.7, excc pl as permi Hed ill Secti on 42 1.7 .3.2.
421.7.3.2 Where membe rs frame into all four sitlcs of lhe joillt ,Hld whe re e:lch mem ber width is: al lellst three-fotlllhs the column width, the amOllrH or reinforcement specified in Seelion 42 1.6.4.4( I) or Seclion 421.6.4.4(2) ,baJJ be permitted to be reduced by half. and the spacing required in Section 421.6.4.3 shall be permitted to be increased to 150
Natlollal Stru ctur,:ll Cocle of th e PllilipplfK~S G~h Edition Volume 1
4·122
CHAPTE R 4 - Structural Concrete
mm within the overall depth II of the shallowest framing member.
(42 1-6)
421.7.3.3 -Longitudinal beam reinforcement outside the column core shall be confined by transverse reinforcement
l,th for a bar with a standard 90·degree hook shall not be les!-;
passing through lhe column that satisfies spacing req uirements of Section 421.5.3.2, and requirements of Sections 421.5.3.3 and 421.5.3 .6, jf such confin ement is not provided by a beam framing into the joi nt. 421.7.4 Shear Strength
For lightweight aggregate concrete, the development Icngth , than the. largest of IDrib. 190 mm. and 1.25 times that requ ired by Eq . 421-6. The 90-dcgree hook shall be locatcd within the co nfincd core of'l column or of a bound;lry member.
421.7.4.1 The nominal Sheil[ strength VII! of the joint shal!
421.7.5.2 For bar sizes 10 mill through 36 nun dimncter, lh l.! development length II' for it straigh t har shall not be Ics~: than the larger of ( I ) and (2):
nOt be taken greate r than the va lues specified below for normal weight aggregate concrete.
I.
times (he leng(h required by Section 421.7.5.1 if (he depth of the concrete cast in one lift beneath the bar docs not exceed 300 111m: and
2.
times the length required by Section 421.7.5.1 if th e depth of the concrete cast in one lift bencath the. bar exceeds 300 mm.
For joints confined on all four faces . .. .. 1.7
.[1;Aj
For jOinls confi ned on three faces or on two opposite
faces For others
J.2
.[1;A/
1.0.[1;A/
A member Ihal frames illio a face is considered to provide con fin cment to the joint if at least three·fourths of the face of the joint is covered by the framing member. Extensions of beams at least one overall beam depth" beyond the joint face are permitted to be considered ali confining members. Exteilsions of beams shall satisfy Sections 421.5. 1.3. 4 2 1.5.2.1, 42 1.5.3.2, 421.5.3.3, alld 421.5.3.6. A joint is co nsid ered to be co nfin ed if such confining mcmbers frame into all faces of the joint. is the effective cross·sec{jonal area within :t join! computed from joint depth times effective joint width. JOlm depth shall be the overall depth of the column , II . Effective joint width shall be the overall width of the colum n. except where a beam frames inlo a wider column, elTectivc joi nt width , halllla< exceed the smaller of (I) alld (2): AI
421.7.5.3 Strai ght bars terminated i.l1 a JOInt shall pa s~ through the con fined co re of a coluilln Or o f 11 boundary mcmber. Any portion of the strai ght embedment length, 1.1 no t withi n the confined core shall be increascd by a factor of 1.6. 421.7.5.4 If epoxy-coated reinforce ment is used, the lengths in Sections 421.7 .5.1 through 421.7 .5.3 shall be multiplied by (he applicable factor specificd ill Section 412 .3.4 or 412.6.2.
develo pment
421.8 Special neinforccd COllcrc(' Structllral ':Valls and Coupling Beams 421.8.1 Scope The requircments of Section 421.8 apply 10 special rein ·
forced concrete structural walls and coupling bealns serving
I.
Bea m width plus join< depth :
2.
Twice the smaller pcrpcndi culill' distan ce longi tudinal
as part of th e earthquake forcc-res isting sys tem. SpCCl;;!
from
structural walls constructed using precast conc rcte !-illa;! 'l lso comply with Section 421. 15.
421.7.4.2 For lightweight aggregate concrete, the Ilomimil shear strcngth of the joi nt sh
421.8.2.1 The <'\i slributc(.\ web rcinfon.:cmcill fillios, p,. aod P.!> 1'01' st ructural walls sha ll not be less than 0.0025, cxtl'11:
421.7.5 Developmcnt L..cngth of Bars in Tcns io n
P•. •1Ild PII' shall be permitted to be reduced to that requlJ(·d
421.8.2 Reinforcement
if (he design shc;u force. V" docs not exceed (1/12)A(.J.rr:..
421.7.5.1 For bur s i Zt~S 10 mill through 36 mm di . ullctcr, the development length trll, for a bar with n st:lildard 90·dcgrce hook in normal weigh t aggregate co ncrete shall not be less thall the largest of Rtf", 150 111m. and the length required by Eq. 421·6.
in Section 414.4. Reinforcement spacing c. lch W'L)' in sl l1lclural walls shall not exceed 450 LlUll . Rcinfon:CJlICiil co ntlihuting to V" shall he <.·ontinuolls
Associnlion o f Stnlciliral EngIneers of the Philippines
CHAPTEf·~
: 421.H.2.2 A! leasl two curtain s of reinfon.: cmcm shall be
. used in a wa ll if V" cx.n·cus ( 1/6)A"J.J1.. 421.8.2.3
Reinforcement
jn
~Irtl (;turil l
willis
s hall
he
developed or spliced for ./;, ill tension in
The requ ire ments o f Secti o ns 412. 12. 412. 13. :lIld
412. 14nccd not bc .'iUlisficd.
I
. 3.
f
I
rcinforccmcill shall be 1.25 times the for~. ill tension .
va lues caicuimcd 4.
4 123
one of the individual wall picrs, v" shall not bc takcn larger th an 0.8311 ..... . where A, .... is the afca of t:oncrctc sectioll o f" the indiv jdlml pic r considered . 421.8.4.5 For horil',ontal wa ll segme nts and coupli ng beams, \/" slHl Ii not bc t;lkcn !
" ,.p is the area or a hori'l..olllal wall segme nt o r
cou pling bCH I11.
42) .8.5 Design for Flexural and Axia l Louds 421.8.5.1 Stru ctural walls and portions of such w
AI localiolls where yield ill g of IOllgiludillal reinforcement is likely to occur as a result of latenll dis placements, development lengths of Jongitudin
-1 .. Structural Concrete
Mechanical sp lices of reinforcemellt shall conform
to
Section 421 ..1.6 and welded spli ces of re inforce me nt sha ll co nfol1n to Section 421.3 .7 .
421.8.3 Design Force!) The desig n s hear force lIu shall be outai ned from the liller;]]
load analYSis in accordance with the facto red load combinat io ns.
subject 10 com bined flexural and axia l loads s hall be designcd ill accordance with Sections -110.3 and 410.4 except thai Secti on 410.4 .7 .md the nonline'l:f strain req uirements of Section 410.3.2 sha ll no( apply. Concrcte
nangc widths, boundary clements, and th e wall web shall considered effective. Th e effec ts of ope nin gs shalt be considered. b~
421.8.5.2 Unless
421.8.4 Shear Strength 421.8.4.1 Nomi nal shear strengt h VII of structural walls shall not exceed: \I" = A,,·I CI,.(i112 ))',fJ; + p,f, J
(42 1-7)
where Ihe cocfficielll CI,. is 0.25 for 11.11". ~ 1.5, is 0.17 for hJ/II" ~ 2.0, and varies linearl y between O.2~ and 0.17 for 11,11... belweell I .5 alld 2.0. 421.8.4.2 In Seelion 421.8.4. 1. Ihe val lie of ,"Iio 11,/1 .. lIsed for dctemlining V for segments of a wall shall be the larger of the rati os fOf th e entire wall and the segme nt of wall co nsid ered .
421.8.6.1 The need for special boundary elcmenls at the edges of structural walls shall be evaluated in accordance wit h Secti on 42 1.8.6.2 or 421.8.6.3. The requirements of Seeli ons 42 1.8.6.4 and 421.8.6.5 also shall be salislied. 42J.8.6.2 This scction applies to walls or wall piers that are effectively continuous from the base of structure to top of wall aud designed to ha ve a single critical section for fl ex ure and ax ial loads. Walls not satisfyi ng these requirements shall be designcd by Section 42J .7.6.3.
Il
J.
c ~ .=--,/~._-
421.8.4.3 Walls Sh:lll have distril.nllcd shear rei nforcemcnt providing resistan ce in \1,1,10 orthogonal directio ns ill [he plane of th e wall. If" th e ratio h"l/". docs nOI e.xceed 2.0. reinforccment I"il!io PI' sh;lil not be less than rcinforccmcnt nltio p".
bounded by web th ick ness and length of section. For any
(42 1-8)
600(0.' '' .> c in Eq. 421-8 corrcsponds 10 the largest ncu tral (IX is depth calculated fo r the factored ax ial rorce and nominal moment st rength consistent with the design di splacement ()u. Ratio 6.. 111\1' in Eq. 421-8 shall not be laken less Ih an 0.007.
421.8.4.4 Nominal shear strength of all wall piers sharing a Common lateral fortc, Vn shall not be assumed to exceed
(2/3)An' \~J whcre An. is the gross arca of concrete
Compression z.ones shal! be reinforced with special bou ndary clcmenls where:
2.
Whcrc special boundary clements are required by Seelion 421.7.6.2 (I), Ihe spec ial boundary elemenl reinforcemen! shall extend YCl1ically fcom the crit ical
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seclion
it
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Structural ConcretP.
dis{i\JlcC no! less than lhe larger Ilf / .._or M"
/(4 \I..}. 421.8.6.3 Structural walls nol designcd to th e provisions of Section 421.8.6.2 shall have special boundary elcmen!s al
boundaries and edges arou nd openings of structural walls where the Jll
shall be satisfied: I.
2.
The boul1d~lry clement shall extend horizontfllly from the extreme co mpression fibe r a dislance 110t less than the larger of c ~ 0.11".
In flanged sections, the boundary clement shall include the effective flange width in compression and shall extend at least 300 mm into (he web;
3.
Special boundary element transverse reinforcement shal l satisfy the requirements of Se~ t ions 421.6.4.2 th rough 421.6.4.4, except Eq . 421-4 need not be satisfied and the transverse reinforcement spacing limit of Section 421.6.4.3(1) shall be one-third of the least
dimension of the boundary elemcl1I; 4.
Special boundary elemem transverse reinforcement at the wall base shall extend in to the support at least the
42 J .8.6.S Where special boundary clements arc not rC'ql!in~d hy Section 42 1.8.6.2 or 421.8.6.3, the following ~L.!l ;.;: satisfied:
I.
If the longitudinal reinforce-ment ratio al thL'
;~',.i;
houndary is grealer than 2.8/];. boundary tran;; \'( ': .
reinforcement shall satisfy Sections 421.6.4.2, ,i; 421.8.6.4 (I). The maximum longitudinal spacing 0)' transverse reinforc ement ill the boundary shall :, 01 exceed 200 Jlllll ; 2.
Except whell VII in the plane of the w;!l1 h; it.:,:; {han ( 1/12)A •.,.ff,., llorizontal reinftl/"t·t· ;'i:· ..; Icrminaling 81 Ihe edges of struclUral Willi ·; ·.'.il ! ~ I)u t boundary elements shall have a stand m·j ··-::L engaging th e edge rei nforcement or the "dgc reinforcement shall be enclosed in U·stirn1p:. ::".... ,} the same size and spacing as. and spliced :l\ ik· horizontal reinforcement.
421.8.7 Coupling Hea llls
421.8.7.1 Coupling beams with aspect ratio 'II Id -;;' { :1):., 0 satisfy {he requirements of Section 421.5. The prm'i. ,;·.' · Sections 421.5.1.3 and 421.5.1.4 shall not be rcquir",,~ Ii H ca n be shown by analysis that the beam has adcqllal(~ )('(:1 ' "ability.
421.8.7.2 Coupling beams wi lh aspect ralio, /" II! ..-: 2, ;!Jld with faclOrcd shear force V". exceed ing (1I3V \{ i ., A•. ~
shall be reinforced with two intersecting grou /!"- 1)1 ;;i:lr:onally placed bars symmetrical about the midspan, \II ,j- ':s it can be shown thaI loss of stiffness and strength ol Ihe cou pling beams will not impair the vertical load c:· ·'I!lg capacity of the structure, or the egrcss from the stnll:l f"',!J. the integrity of nonstruclUral com ponents itlHi ;· :t·,. connections 10 the Slnlcturc.
development length , ld' according to Section 421.8.2.3,
of the largest longitudinal reinforcement in the special boundary element unless the special boundary element terminates all a footing or mat, where special boundary element transverse reinforcement sha ll extend at least 300 mill into the footing or mat ;
5.
421.8.7.3 Coupling beams nOI governed by Sr·:·! j" 421.8.7. 1 or 421.8.7.2 shall be permitted to he: .,' ; i' ) either with two intersecting groups of bars f-Y;: ,:!"'; about the midspan, or according to Sections ,1) 1 ~\ "through 421.5.4.
Horizon tal reinforcement in (he wall web shall be anchored to develop the specified yie ld strenglh f". wilhin (he confined core of (he boundary element; .
Association of Structural Engineers of the Philippines
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CHAP1TH t1 ... StruC!lJr ..ll Concre le
421.8.7.4 Coupling beams rcillror<.·t~d w ith (WO intcl'<;ccling gro ups III' diagollally placed hm '~ sj'IIlIHelricid ilbout Ihe midspan shall salisfy (I). (2). and cilher (3) nr (4). Requirell1enls Secti on 411.9 sh
or
1.
(42 1-9)
3.
Joint~
A ll construction joints ill structu ra l walls shall con form to Section 406.4 and contac t su rr
Seclion 411.8.9.
The nominal shear stn..:nglh. VII' sImI! be determined
by:
2.
421.8.8 Construction
t1·12~
Etlch grmlp or di sha ll be embedded into the wall not less than 1.25 times (he devclopmem knglh ror /; in te nsion.
Eile l! grou p of diagonal hars shall be enclosed by transverse reinforcement having oul-(o-out d imensions not smaller than b,/2 in thc direction paralicilO b w
or
4. Transverse reinforcement shall be provided for the entirc beam cross section satisfying Sections 421 .6,4,2. 421.6.4.4, ..md 421.5 .4.2. with long iludina l splicin g l10t exceeding the smalle r of 150 mm and six times the diamcter o f the diagoll
421.8.9 Discontinuous Walls Co lumns supporting discontinuous structuml Willis shall be. reinforced in accorda nce with Section 421.6.4.6. 421.9 Structural Diaphragms and Trusses
421.9.1 Scope Floor and roof slabs acting as Sll1Jc lUral diaphragms to Iransmit design :'lc tiollS ind uced by ea rthquake ground motions shall be designed in accordance with this Sec ti on 42 1.9. Th!:-; Section also applies to strul S, ti l!s, c hords, and co llector clements th at transmit forces induced by earthquakes, as well as tru sses servi ng as parts of the ea rthquake force-resisting sys tc ms.
421.9.2 Design Forces The seismic design forces for stru ctural diaphragms shall be obta ined from {he lateral load analysis in accorda nce with the design load combinatiolls .
421.9.3 Seismic Load Path 421.9.3.1 Alr diaphragms and the ir connect ions shall be proportioned and de(ai led iO provide for a completc lransfer or fo rces to coll cclOr eleme nts and to the venical clements of the seismic-foree-resisting syste m . 421.9,3.2 Elemcnts of a stnlctural diaphragm system thai are subjected primarily to axial forces and used to transfer diaphragm shear or flexura l forces around openings or other discont in ui ljes, shall comply with the requirements for colleclors in Seclions 421.9.7.5 and 421.9.7.6.
421.9.4 Cast-in-Place Composite-Topping Slab Diaphragms A composite-lopping slab Gast in place o n i.l precast noor or roof s hall be pcrlllitt ccl io he used .1S a strucltlral diaphragm provi ded the lOpping slab is rei nforced <111(1 it s connections arc proportioned and detailed to pmv id e for a co mpl ete transfer o f forces 10 chords, collector elements. and the late ral-force-resisting system. The surface of the previously hardened concrete all which the topping sial.> is placed shall be clean, free of iaitance, and intenti onall y roughened.
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421.9.5 Casl-in-Plner Topping Slab Diaphragms
res isting sys tem, thc limi! of 0.2[. ' shall he ilKTc;!scd to
A cast -in-pl;\(,.'c non-l:ompOSilc lOpping on a prccast Ooor or roof shall be penni lied 10 serve as a struclural di'lphragm, provided the casi-i n-place lopping acting alone is propol1ioncd and dCI
O.v.', and the limit ofO . I S]; ' shall be increased In 0.4[,,' .
421.9.7.6 LongilUdi nal reinforceme nt 1'0.. colleclor cleme nts iii splices alHI illlchoragc I'.ones shall have either:
I. 421.9.6 Millimum Thickness of Diaphrag ms Co ncrete slabs and composi tc lOpping slabs servi ng as sl ru clural dia phragms used to transmit ea nhquakc forces shall flat be less than 50 10m th ick. Topping slabs placed ovc r prccast Ooor or roof eleme nts, acting as structurn l diaphragms and not relying on composite ac tion with the precast elemclHs 10 rcsisl the design seismic forccs. sh:11I ha ve thi ckness not less than 65 mm.
A minimum cemer-to-ccnler spacing of three longi tudin al bar diameters. but not less than 40 111111, aI~d a minimum concret e clellr cover or two llnd onehail longitudinal har diameters, bUl nol less Ih'lI1 50 mill; or
2. Transverse reinforcement (is required hy Section 411.6.6.4. cxCCpl as required in Seclion 421.9.7.5.
421.9.8 Flexural Strength 421.9.7 Reinforcement
Diaphragms and port ions of d:aphragms shall be designed for nex ure in accordance with Scctions 410.4 and 410.5 exeCI'I 111m the nonlinear di stribut ion of strain requ irements of Section 410.4 .2 for deep bea ms need not appl y. The efrects of openings slwll he co n s id c n~d .
421.9.7.1 The minimulll reinforcement rati o for structural diaphragms slwll he in conformancc with Secti on 407. I 3. Reinforccmcnt spaci ng each wa y ill non-post te nsioned fl oor or roof sys tems shall not exceed 450 mill. Where welded wire fabric is used as the di stributed reinforceme nt to resist shear ill lOpping slabs placed over precast 0 001' and roo f clemcnts. th e wires parallel to th e span of tile precas t clcments shnl1 be spaccd nol less than 250 mill 011 ce nt er. Reinforcemen t provided for shear strength shall be cont inuous and shall be distributed uni fo rml y acro!>s thc shear plane.
421.9.9 Shear Strength
421.9.7.2 Bonded prest ressing tendons used as primary reinforcement in diaphragm chords or collectors shall be proportioned such that the stress due to dcsign seis mic forces does not exceed 415 MPa. Pre-compress ion from unbonded tendons shall be penniHcd to resist diaphragm design forces jf a complete load path is provided.
For cast-in-pl ace topping slab diaphragms on precast 0001' or roof members, An shall be computed using the thickness of topping slab only for non-compositc lopping slab dial-!~ragms and Ihe combined thi ck ness of cast-in-place and precast clements for composite topping slab diaphragms. For composi te topping Si;lb diaphragms. the value of J/ used to determine \I" shall not exceed the smaller ofJ/ for Ihe precnst membcrs andj;.' for the lopping
421.9.7.3 All reinforcement used to resist collector forces, di aphragm shear. or flexural tension shall be developed or spliced for j,. in tensioll . 421.9.7.4 Type 2 splices arc requ ired where mechanica l splices nrc lIsed to transfer forces between the diaphragm and the veni cal elemen ts of the seismi c-fo rcc-re:sisting sys tem. 421.9.7.5 Collector clements with compressive stresses exceedi ng O.2ft at any section shall have transverse reinforcement , as in Sections 421 .8.6.4 (3) over thc Icngth of the clemcnt. The special transverse reinforcement is allowed to bc di sco ntinued at a section where the calcul atcd compressive strength is less than O.15fe.
Where design forces have been amplified to accoun t for the
overstrcngth of the vertical elements of the seismic··force·
Nominal shcar strcngth V" of stru ctural diaphra gms shall not exceed:
v" = A,, 111!6)!.J/", +M,·)
(421 ·10)
sl ab.
421.9.9.2
Nominal
shear
strength
diaphragms shall not exceed 0.66 A".
V"
.rr:.
of structural
421.9.9.3 Above joints bctwecn precast clements in noncomposite and composite cast·i n.plncc lOpping :;Ial: diaphragms, VI/: shall not exceecl :
"II = A'ff.·JI
(421-1 l)
where A", is {olal area of shea r fric tion reinforcement wili,;n topping slab, including both distributed and hOIl!H :" .~ reinforce ment, that is ori en ted perpend icular to joint s ;;. !' . ' precast system and coeffici ent or fri cti on, fl, is I.OA. wl J{;~ A is given in Section 411.8.4 .3. At leas t one- hal f of A,.' :: ,I be uniformly distributcd along the length of lhe pOle.:
Association of Structu ral Engineers of the Philippines
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CHAPTER 4 " Structural Concrete
shear plane. Area of distributed reinforccment in topping slab shall satisfy Scction 407.13.2.1 in cach direction. 421.9.9.4 Above joints betwecn precast elemerlls in noncomposite and composite cast-in-place topping slab diaphragms, VII shall not exceed the jimits in Section 411.8.5 where Ac is computed using the thickness of the topping slab only.
421.9.10 Construction Joints
All construction joints in diaphragms shall conform to Section 406.4 and contact surfaces shall be roughened as in Section 411.8.9. 421.9.11 Structural Trusses 421.9.11.1 Structural truss clements with compressive stresscs exceeding 0.2/,,' at any section shall have transverse reinforcement, as givcn in Sections 421.5.4.2 through 421.6.4.4
421.10.2.3 Columns or boundary clements of special reinforced concrete structural walls that have an edge within one-half the footing depth from an edge of the footing shall have transverse reinforcement in accordance with Sections 421.6.4.2 through 42 J .6.4.4 provided below the top of the footing. This reinforcement shaH extend into the fOOling a distance no less than the smaller of the depth of the footing, mat, or pile cap, or the development length in tension. 421.10.2.4 Where earthquake effects create uplift forces in boundary elements of special rcinforced concrete structural waHs or columns, flexural reinforcement shall be provided in the top of the footing, mat or pile cap to resist the design load combinations, and shall not be less than required by Section 410.6. 421.10.2.5 See Section 422.11 for use of plain concrete in footings and basement walls.
421.10.3 Grade Beams and Slabs on Grade 421.10.3.1 Grade beams designed to act as horizontal ties between pile caps or footings shall have continuous longitudinal reinforcement that shall be developed within or beyond the supported column or anchored within the pile cap or footing at all discontinuities.
42I.l0 Foundations 42I.l0.1 Scope 421.10.1.1 Foundations resisting caJ1hquake-induced forces or transferring earthquake-induced forces between structure and ground in structures assigned to scismic zones 4 and 2, shall comply with Section 421.10 and other applicable code provisions. 421.10.1.2 The provisions ill Section 421.10 for piles. drilled piers, caissons, and slabs 011 grade shall supplement other applicable code design and construction criteria. See Sections 401.1.5 and 401.1.6. 421.10.2 Footings, Foundation Mats, and Pile Caps
421.10.2.1 Longitudinal reinforcement of columns and structural waHs resisting forces induced by earthquake effects shall extend into the footing, mat, or pile cap, and shall be fully developed for tension at the interface. 421.10.2.2 Columns designed assuming fixed-end conditions at the foundation shall comply with Section 421.10.2.1 and, if hooks are required, longitudinal reinforcement resisting flexure shall have 90-degree hooks Ileal' the bottom of the foundation with the free end of the bars oriented towards the center of the column.
421.10.3.2 Grade beams designed to act as horizontal ties between pile caps or footings shall be proportioned such that the smallest cross-sectional dimension shall be equal to or greater than the clear spacing between connected columns divided by 20, but need not be greater than 450 111m. Closed ties shall be provided at a spacing not to exceed the lesser of one-half the smallest orthogonal crosssectional dimension or 300 mm. 421.10.3.3 Grade beams and beams that are part of a mat foundation subjected to flexure from columns that are part of the lateral-force-resisting system shall conform to Section 421.5. 421.10.3.4 Slabs-on-ground that resist seismic forces from walls or colulllns that are part of the lateral-force-resisting systcm shall be dcsigned as structural diaphragms in accordance with Section 421.9. The design drawings sha!1 clearly state that the slab-Oil-ground is a structural diaphragm and part of the lateral-force-resisting system. 421.10.4 Piles, Piers, and Caissons
421.10.4.1 Provisions of Section 421.10.4 shall apply to concrete piles, piers, and caissons SUppoI1ing structures dcsigned for earthquake resistance.
th
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CHAPTEH:1 ·- Strutlural Concrele
421.10.4.2 Piles, piers, or caissons rl!~i~ ling tens iull loaus shall ha ve continuous longitudill'll fcillforccmcill over the length resisting design tension fon:cs. The longitud inal reinforce ment shall bc dChlilcd to trans fer (c nsion forces within the pile ca p 10 ~u pport cd structu ral members.
421.10.4.3 Where tension fon..: es illdu~cd by earthquake effects
421.10.4.4 Piles, piers. or caissons shall havc transverse reinforcemellt in accordance with Secti ons 42 1.6.4 .2 through 42 1.6.4.4 at the following locati ons: 1.
AI the lap of the member fo r at teast .') limes the
member cross-sectional dime nsion, hut nol less than 1.8 Ill. below the bUllom of the pile cap: 2.
For the portion of piles in soil that is not capahJc o f pro vidi ng lateral support, or in air and water, alon g th e entire unsupPol1ed length plus th e length required in Section 42 I. I O.4. 4( I).
421.10.4,5 For precast concrete driven piles, the length of transverse reinforcemel1t provided shall be suffi cient to account for potential varia tions in the elc.vlI tion in pile tips.
421.10.4.6 Conc rete piles, piers, or caissons in foundmions supporting one- and two-story stud bearing wall construction are exempt from the tr<'ll sverse re inforcement requirements of Sections 42 1. 10.4.4 and 421.10.4.5. 421.10.4.7 Pile caps incorpora ting bauer piles shall be designed to resi st the full compressive strength of the bauer piles act ing as short columns. The slendemess effects of balter piles shall be considered for the pOl1ion of ihc pi les in soil that is not capable of providing laterClI support, or in air or water.
421.11 Memoers not Designated a s Part of the SeismicForce-Resisting System
it shall be pcnllllll'd 10 ap ply th:.: rl· lltl i rl..~lll l'l lI .... of Sect ion 421. 11.4 . For two way ~ " Ibs wi thuut bl"!.iI11S, slab.colul1l1l cnnnccliolls slwli 1l1L'I,.' ! Ihe rl'lj ll in.: mcllIs of Secti o jj 42 1.11.6.
421.1 1.3 Wh ere !he indu ced 1ll011H!lIl s al1d shears under design displ acement.. . of Sl"l"liOIl 421. I 1.2 combil1ed with Ihe factored gravity mome nts and shean.; do 110 t exceed the design moment and shear strength of tl w frame lIlelllber, thl~ conditions of Sc(.:tions 421.! 1. )', 1, 421 . 11.l .". an.; ! ~2 I .1 1.33 shall he satisfied. For this purpose, the l:r:l vi h IOCld combi nat ions ( 1.21)+ I .OL+O.·2S) Or 0.9D. whicl ;t~"e r ·i·~ critical. sh
ir
421.11.4.1 Materia ls shaH
satisfy Sectio!1';
'12 1.~/.) ,
421.3.4.3, 421 .3.5.2. 42 1.3. 5.4, and 421.3 .5.) M"c1", ,';c;,1
spli ces shall sal isfy Section 421.3.6 <1Jld ,\ ,.Id;, j .. :" shall smis fy Section 421.3 .7. 1.
421.11.1 Scope
Requirements of Section 421.11 appl y to frame members not designated as part o f the se is mi c- force~ resis ling system in structures assigned lO seismic zones 4 and 2. 421.11.2 Frame members assumed not to contribute to lateral resistance, except two~way slabs without beams, shall be detai led according to Sections 42 1.11.3 or 421.11.4 depending all the magnitude of moments induced in those members if subjected to the desi gn di splacement, 0". If effects of design displacements arc not explicitly checked,
421.11.4.2 Mem bers with faclored grav it y }lxi;!! fnrrl'.:-> not exceeding AJ 'J IO shall stlli sfy Sections 'i .! ·,d 421.5.4. Stirrups shall he spaced a\ not I1lUI{~ Ihan dfl througho ut the length of the membe r. 421.11.4.3 Members wi th factored gra vit y exceedi ng Agref iO simll sati sfy Sections (t2 ~ .' J •• ~ , 421.6.5 and 421.7.3. J.
Association of Structural Engineers of the Pllilippines
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421.11.5 I)rccast C()Jlcrctc frame mcmbers assLJmcd llot to contributc to lateral resistance, including their cOllnections, shall satisfy (I), (2), and 0), in addition to Sections
reinforcement details in any span resisting moments caused by lateral force /:.; shall satisfy Section 421.12.6.
421.11.2 through 421.11.4:
421.12.3 Design shear strength of beams, ¢VII' and columns resisting earthquake effect E shall not be less than the smaller of (1) and (2):
J.
Tics specificd ill Section 42l.lJ.3.2 shall be provided over the elltire colullln height, including the dl~pth of the beams;
2.
Structural integrity rcinforcement, as specified in Section 416.6, shall be provided; and
3.
Bearing length at support of a beam shall be at least 50 mm longer than determined frolll calculations using bearing strength values from Section 41O.18.
For slab-column connections of two-way slabs without beams, slab shear reinforcement satisfying the requirements of Sections 411.13.3 and 411.13.5 and providing V~ not less than 0.29 b;;d shall extend at least four times the slnb thickness frolll the face of the support, unless either (I) or (2) is satisfied:
I.
The sum of the shear associated with development of nominal moment strengths of the member at each retrained !!pd of the clear span and the shear calculated for factored gravity loads;
2.
The maximum shear obtained froln design load combinations that include earthquake effect E, with E assumed to be twice that prescribed in Section 208.
421.11.6
JT
J.
2.
The requiremcllts of Section 411. I 3.7 using the design shear \lug and the induced moment transferred between the slab and column under the design displacement; The design story drift ratio docs not exceed the larger orO.D05 and [0.035 - 0.05(1I,,/¢II,)).
Design story dri ft rati.o shall be taken as the larger of the design story drift ratios of the adjacent stories above and below the slab-column connection. Ve is defined in Section 411.13.2. Vug is the factored shear force on the slab critical section for two-way action, calculated for the load combination 1.2D + I.OL + 0.2S. The load factor on the live load, L, shall be permitted to be reduced to 0.5 except for garages, areas occupied as places of public assembly, and all areas where L is greater than 4.8 kN/m2
421.12.4 Beams 421.12.4.1 The positive moment strength at the face of the joint shall be not less than one-third the negative moment strength provided at that face of the joint. Neither the negative nor the positive moment strength at any section along the length of the member shall be less than one-fifth the maximum moment strength provided at the face of either joint. 421.12.4.2 At both ends of the member, stirrups shall be provided over lengths equal to twice the member depth h
measured from the face of the supporting member toward midspan. The first stiITIlp shal! be located at not more than 50 mm from the face of the supporting member. Maximum stirrup spacing shall not exceed the smallest of: I.
d/4;
2.
Eight times the diameter of the smallest longitudinal bar enclosed;
3.
Twenty four times the diameter of the stirrup bar; and
4.
300 nun.
421.12.4.3 Stirrups shall be placed at not morc than dl2 throughout the length of the member.
421.12 Requirements for Intermediate I\1oment Frames,
Seismic Zone 2
421.12.5 Columns
421.12.1 The requirements of Section 421.12 apply to
intermediate moment frames forming part of the scismicforce-resisting system in addition to those of Sections 401 through 418.
421.12.2 Reinforcement details in a frame member shall satisfy Section 421.12.4 if the factored compressive axial load for the member does not exceed At/'jlO. If Pil is larger, frame reinforcement details shall satisfy Section 421.12.5. Where a two-way slab system without beams forms a part of the seisI1lic~force-resisting system,
421.12.5.1 Columns shall be spirally reinforced in accordance with Sections 407.11.4 or shall conform with Sections 421.12.5.2 through 421.12.5.4. Section 421.12.5.5
shal! apply to all colulllns, and Section 421.12.5.6 shall apply to all columns supporting discontinuous stiff members.
National Structural Code of 1I1e Philippines 6'" Edition Volume 1
4-130
CHAPTER
<1 ~.
Structural Concrete
421.12.5.2 AI both ends of the column. hoops shall be pro vided ill sp:lci ng SOl Over "I length I" measu red from thc j Oi lll facc. Spacing .\'/. sha ll !lot exceed the small e st oj' (I). (2). (3). and (4);
or the
I.
Ei gh t times the diametcr bar enclosed;
smallest longi tudinal
2.
24 times the diameter of the lic bar:
3.
Onc·llUlf of the smallest cross sccti oll
4. 300 nlln Lenglh I" shall nOI be less Ihall Ihe largesl 0 [: I.
One·sixlh of the clear span of the membc.r;
2.
Ma xi mulll cross-sectional dimension of the column; and
3.
450 mm.
421.12.5.3 The first lie shall be loc,ated at not more th an s./l fro m the joint face. 421.12.5.4 Outside the length 1,,, spacing of transvcrse reinforcem ent shall conform (() Sections 407.1! and 411.6.5. 1. 421.12.5.5 l oi nt reinforcement shal l conform to Section 411.1 2. 421.12.5.6 Columns suppol1ing reac ti ons fro m discontinuous stiff members, such as walls, shall be provided wilh transverse reinforcement at th e spacing, s," as defined in Seclion 42 1.12.5.2 over Ihe [ul1 heighI benealh the le vel at whi ch the discontinuit y occurs if (he porti on of fac tored axial co mpressive force in these mem bers related to earthqu ake effects exceeds AJ,' flO. Where design forces have becn magnified to aCCOUfl{ for the overstrenglh of the vertical elements of th e seismic- fo rce~resi sting system, th e limil o[ AI,' 110 shall be increased 10 AI,' 14. This transverse reinforcement shall extend above and below the columns as required in 42 1.6.4 .6 (2). 421.12.6 TWO-Way Slabs Without Beams 421.12.6.1 Factored sltlb moment at support incl udin g earthqllake effects. E, shall be dctennined for load combinalions defined by &15 . 409-5 and 409-7. All reinforcement provided to re sist M,f, the pOlt ion of slab moment balanced by sllppon mome nt shall be placed within the column strip defined in Sectio n 4 13.3. 1.
421.12.6.2 Reinforcemcnt placed wililin the effect i Ve widt h speci fi ed in Secti on 4 11.6.3.2 shall be propo l1 io ncd to resis t 11A'I~loIIr Efl'cctive slab wid th for exte rior and co rnel' l:l>nncclions shall not ex tend beyond the column face a distance grc
421.12.6.3 Not Jess than o ne~halr of the reinforce ment in Ihe column strip at SUppOI1 shall be placed wi thin the effecti ve slab width specified in Secti on 4 13.6.3.2. 421.12.6.4 Nol less Ihan one-fou rt h o[ Ihe lOp reinfo rcement at the support in the column strip sll
421.12.6.5 Continuous bottom reinforcement in the column strip shall be not less than o ll c~third of the top reinforcement at the support in the column slIip. 421.12.6.6 NOl less Ihan one-hair o[ all bOllom re inforcement and all bottom column strip reinforcement at midspan shall he cominuous and sllflll de velop its yield strenglh, .f;., at f
421.12.6_7 Al di sconlinuous edges o [ Ihe slab all lOp and bOllom reinforcement at suppon shall be and shall be deve loped at the face of suppo n as defi ned in Section 4 13.7.2.5. 421.12.6.8 At th e critical sec tions for columns defined in Section 4 I 1.13.1.2, lwo ~ way shear caused by factored gra vity loads shall not exceed O.4¢Vr' where Vt shall be calculmed as defined in Sectio n 411.1 3.2. 1 for nonprestrcssed slabs and in Seelioll 411 .13.2.2 for prestressed slabs. It shall be permitted to waive this requi rement if the slab design satisfies requirements of Seclion 42 1.11.6. 421.13 Special Moment Frames Using Precast Concrete 421.13.1 Scope Requirements of Section 421.13 app ly to speciaJ mOlrw> t frames conslm cteu llsin g precas t concrete fonning pari u[ the seismi c-forcc-resistin g sys tem. 421.13.2 Special moment frames with ductile COllllcctions constru cted using precast co ncrete shall satisfy (I ) an d (2) and all requirements for special moment frames constfllcll.(: with cas l -i n~pl ace concrete: I.
Vn for connecti ons computed acco rding to Sf' ''!!'''' 4 11 .8.4 shall nOI be less Ihan 2V, . wh,-!e L ". caleulaled according 10 Seclion 421.5 .4.1 or 4 ?.1.('. 5.1 ;
As sociation of Structural Engineers of the Philippines
r 2.
CHAPTER 4·· Structural Concrete
Mechanical splices of beam reinforcement shal! be located not closer than hl2 from the joint face and shall meet the requirements of Sections 42! .3.6.
421.13.3
Special moment frames with strong connections
constructed using precast concrete shall satisfy all requirements for special moment frames constructed with cast~jn-placc
between locations where- flexural yielding is intended to occur due to design displacements;
3.
Design strength of the strong connection, ¢lS,!> shall be not less than S/.; Primary
longitudinal
reinforcement
shall be made
continuoLls across connections and shall be developed
outside both the strong connection and the plastic hinge region; and 4.
Columns having clear height less than or equal five times the dimension shall be designed for shear in accordance with Section 421.12.3. (0
c,
421.15 Special Structural \Valls Constructed Using Precast Concrete
concrete, as well as (I), (2), (3), and (4).
1. . Provisions of Section 421.5.1.2 shall apply to segments
2.
421.14.3
4·131
For column-to-column connections, ¢ Sf) shall not be less than 1.4 Sr. At column-to-column connections, ¢Mil shall be not less than O.4M,If for the column within the story height, and ¢V/I of the connection shall be not less than Vr determined by Section 421.6.5.1.
421.15.1 Scope Requirements of Section 421.15 apply to special structural walls constructed using precast. concrete forming part of tile seismic-foree-resisting system.
421.15.2 Special structural walls constructed using precast concrete shaH satisfy all requirements of Section 421.8 in addition to Sections 421.4.2 and 421.4.3. 421.15.3 Special structural walls constructed using precast concrete and un banded post-tensioning tendons and not satisfying the requirements of Section 421.15.2 arc permitted provided they satisfy the requirements of ACI lTG-S.1.
421.13.4 Special moment frames constructed using precast concrete and not satisfying the requirements of Sections 421.13.2 or 421.13.3 shall satisfy the requirements of ACI 374.1 and the requirements of (I) and (2): 1.
Details and materials used in the test specimens shall be representati ve of those used in the structure; and
2.
The design procedure used to proportion the test specimens shall define the mechanism by which the frame resists gravity and earthquake effects, and shall establish acceptance values for sustallung that mechanism. Portions of the mechanism that deviate from Code requirements shall be contained in the test specimens and shall be tested to determine upper bounds for acceptance values.
421.14 Ordinary Moment Frames 421.14.1 Scope Requirements of Section 421.14 apply to ordinary moment frames forming part of the seismic-foree-resisting system.
421.14.2 Bcams shall have at least two of the longitudinal bars continuous along both the top and bottom faces. These bars shall be developed at the face of SUppOIt.
National Structural Code of tile Philippines 6'" Edition Volume 1
4· 132
CHAPTER 4 _. SUUGIUral C onCICIC
422.2.3 For unusual structures. stich as arches. underground lItility structures. gmvity wall s. and shieldi ng wa ll ~ provisions o f (hi s section shall govern where appli cable. . , 422.3 422.1 Nolalions
Ax AI
A2
= gross
= loaded
b b"
cone, or tapered wedge co ntai ned wholly within the suppon and havi ng for its upper base the loaded area, and having side slopes of I vertical to 2 horizontal. mm? :: widt h o f member, mm :: perimeter of criti cal secti on for shear Ln footings.
8"
:: nominal bearing load
/" .
:: specified co mpressi ve stre ngth o f co nc rete. MPa Sec Seci ion 405
Lim ita( i oJl~
422.3. 1 Provisions of Section 422 shall apply for design of s tru ctural pl ai n concrete members defined as eith er unreinforccd or cont;ti nin g less rr:;nforcement than t h;:o: minimum alllount specified in thi s code ror rcinforl:(.·,- ! concretc. See Secti on 402. 422.3.2 Use of structural plain concrete shall be limited to :
I.
Members that arc contin uously supported by soil or supported by other structural members capablc of provid ing conti nu ous vertical suppo rt ;
111111
ff :: square root of specified co mpressive s-t rcnglh of con crete, MPa average sp lilting ten si le strengt h of li gillweigh t aggregate conc rete, MPa. See Secti ons 405.2.4 and
fr,
;;:
h
405.2.5 :: overa ll thickness of membe r, mil)
Ie
:: vertical distance between supports, mJl1
M"
:: l10 mi nal moment s lrc ngth at sec tion
2.
Members for whi c h arch act ion provides compress io n under a ll condit ions of loadin g; or
3.
Wall, and pedestals. Sec Secli ons 422.7 and 422.9.
The usc of structural plain co nc rete co lumns shall not pcnnitted. 422.3.3 Section 422 shall not gover n design and installati on of cast -in -place co ncret e piles and pi ers embedded in ground.
M il
:: fac tored moment
Pit
:: nominal slrength of cross sec ti on s ubj eci to
422.3.4 Minimum Specified Strength
compression = nominal ax. ial load strength of wall designed by Sec lion 422 .7.5 :: factored axial load at given ecce ntricity :: c lasti c secti o n modu lus of secli on :: nomina l shear strength at section :: shear stress due to factored shear force al secti on. :: fa ctored shear force at secli on = ratio oflong side to short side of concentrated load or reacti on area :: strength redu c tion fact or. See Section 409.4 .5
Specified com pressive strength of plai n concrete to be used for structural purposes shall not be less th an the larger of 17 MPa and that required fo r durability in Section 404.
p"... P" S
V" Pit
VII
Pc ¢
31
section
422.2 Scopc 422.2. t Section 422 provides minimum requirements for design and constl11clion of s tructura l plltin co ncrCl e members (cast-ill-place or precast). 422.2.2 Unl ess in conniel with the provisions of Sec tion 422, Ihe roll owing provi s ions o r Ihis Code sha ll app ly 10 s tructural plai n conc rete members: Sections 40 1. ·1 through
407.6, 407.7. 1, 407.7.2, 407 .7.4. 407.8, 409.2.3, 409.3, 409.4.5, Secli ons 420, 421.10.2.5, 426.409.3, 426.409.3.5, a nd Seclion 423.
422.3.5 Seismic Zones 2 and 4 . Pl a in concrete sh
Assoc iali ol1 of S tructura l Eng ineers of the Phil ipp ine s
j, .j
CHAP rt:= n -1 .• StrllcllI ra l Concrete
421-.5 Design Method 422.5.1 ~
StmcIlIfil l plain
concre te
membe rs
shall
be
des igned for adcquill c sire ngth in accordallce WiLh the code,
/: using load faclOrs and design strength . 422.5.2 Factored load s and forces shall be in co mbinations as in Section 409 .3 . 422.5.3 Where rcqtli rcd strength ex ceed s des ign slfcnglh, rei nforceme nt shall be prov ided a nd the me m be r designed
as a reinforced cancreIC member in accord ance with appropriate des ign require me nt s of the code. 422.5.4 Strength design of st ructural plai n conc re te mem bers fo r fl exure and axia l loads shall be based on a li near stress-stra in relationShip in both te nsion ~md compress ion. 422.5.5 Ten sile strength of conc rete 5h
ass igned
to
subject In
p"
0
comrrcs~i()11
(422-4)
(JPt! ~ P" whe re PI' is factored load Hnd strc ngth co mputed by:
I
I
scc t ion~
422.6.2 Des ign of cross shall he based on:
4- 133
»11 is
·1· (.32 -!,---) 11 ' JA
0.60} , I -
nomin al com p re~s i()11
(4 22-5) I
where A 1 is the loaded mea. 422.6.3 Me mbers su bj ec t 10 combined nexure and axial IOitd in compress ion sha ll be propol1i o ned such tha t On the com press ion face:
1',,/ ¢P" + M"/$M,
rI 1
(422-6)
and 011 the te nsio n face:
M"/S -Po/A, ,; OA2(!J.ff.
(422-7)
422.6.4 Design of recl1lll gular c ross sec ti ons subject 10 3hear shall be based on :
steel
(422-8) whe re V" is factored shear and V'I is nominal shear stre ngth
422.5.7 Tens ion shall not be transmitted through ou tside edges. constru cti on j oi nt s. contracti on joints. or isolati on j oints of an indi vidua l pl a in concrete ele men!. No ne xural contin uit y due to tc nsion shall be assumed be tween adjace nt sU11cw ra l plain concrete e lement s. 422.5.8 When comput ing strength in flexure. combined flex ure and axial load, and shear, the ent ire cross section of a member shall be considered in des ign. except fo r conc rete cast aga ins t soil where overa ll thi c kness II sha ll be take n as 50 mm less tha n act ual thi c kness .
compu ted by:
v,
= 0. 11 ).
ff. b,.h
(422-9)
for bea m acti on and by:
(422-10)
for two-way aClion but nol greater than O.22.l../T: bjl. In Eq . 422- 10./1 correspo nd s '0 rat io of long s ide 10 short sid e of co ncentrated load or reaclion area.
422.6 Strength Design 422.6.1 Design of cross sections subj ect to ne xure shall be b ased on
(422- 1) where Mu is factored mo me nt and Mt! is nomiB
M"
= (51J2)J../T: S,"
(422-2)
if tension controls, and
422.6.5 Design of bearin g areas subject to compress ion shall be based on:
(422-11 ) where E" is rac tored bearing load and Bn is the nomina l bearing strength of loaded a rea A I computed by:
B,
= 0.85!"
(422- 12)
AI
except where the supporting surface is wider Oil all side., than the loaded area, design bea ring strenglh on the loaded arca shall be m ultipli ed by
JA, I A,
(422-3)
if compressi on contro ls, whe re. Sill is th e correspondin g elastic section modulu s.
National Stru ct ura l Code of the Philippines 6'h Edition Volume 1
bu. not more .han 2.
4·134
CHAPTE~~
4 .- Sll"Uclural Concrete
422.6.6 Lightweight Concrete Modification factor ), for lightweight concrete in this Chapter shall be in accordance with Section 408.7. J unless specifically noted otherwise.
422.7 Walls 422.7.1 Structural plain conCk .. .; walls shall be continuously supported by soil, footings, foundation walis, grade beams or other structural members capable of providing continuous vertical support. 422.7.2 Structural plain concrete walls shall be designed for vertical, lateral and other loads to which they arc subjected. 422.7.3 Structural plain concrete walls shall be designed for an eccentricity corresponding to the maximulll moment that can accompany the axial load but not less than O. 1011. If the resultant of all factored loads is located within the middJc- third of the overall wall thickness, the design shall be in accordance with Sections 422.6.3 or 422.7.5. Otherwise, walls shall be designed in accordance with Section 422.6.3. 422.7.4 Design for shear shall be in accordance with Section 422.6.4.
422.7.6.2 [:xccpt as provided for in Section 422.7.6.3, thickness of bearing walls shalJ [lO! be less than 1/24 the unsupported height or length, whichever is shoneI', nor less than 140 1111ll.
422.7.6.3 Thickness of exterior basement walls foundation walls shall be nol less than 190 mill.
and
422.7.6.4 Walls shall be braced against lateral translation. Sec Sections 422.4 and 422.5.7. 422.7.6.5 Not less than two lZl16 min bars shall be provided around all window and door openings. Such bars shall extend at least 600 Illill beyond the corners of openings.
422.8 Footing 422.8.1 Structural plain concrete footings shall be designed for factored loads and induced reactions in accordance with appropriate design requirements of this Chapter and as provided ill Sections 422.8.2 through 422.8.8. 422.8.2 Base area of footing shall be determined from un factored forces and moments transmitted by footing to soil and permissible soil pressure selected through principles of soil mechanics. 422.8.3 piles.
Plain concrete shall not be used for footings
OIl
422.7.5 Empirical Design Method 422.7.5.1 Stmctural plain concrete walls of solid rectangular cross section shall be permitted to be designed by E.q. 422-13 if the resultant of all factored loads is located within the middle-third of the overall thickness of wall. 422.7.5.2 Design of walls subject to axial compression shall be based on:
422.8.4 Thickness of structural plain concrete footings shall be not less thall 200 mm. Sec Section 422.5.7. 422.8.5 Maximum factored moment shall be computed at critical sections located as follows:
loads in
J.
At the face of the column, pedestal or wall, for footing supporting a concrete column, pedestal or \vall;
(422-13)
2.
where Pu is the factored axial load and PII is nominal axial load strength computed by:
Halfway between center and face of the wall, for fOOling supporting a masonry wall;
3.
Halfway between face of column and edge of steel ba~c plate, for footing supporting a column with SiC": ba~:c: plate.
PfI~' = 0.45!' (~ A [1 - (-'"--) 32h
'I
(422-14)
422.8.6 Shear in Plain Concrete Footing 422.7.6 Limitations 422.7.6.1 Unless demonstrated by a detailed analysis, horizontallcngth of wall to be considered effective for each vertical concentrated load shall not exceed center-to-center distance between loads, nor width of bearing plus four times the wall thickness.
422.8.6.1 Maximum factored shear shall be (:omputed in accordance with Section 422.8.6.2, with loc;!!!"" of 'TiticnJ r section measured at facc of column, ped ,"" footing supporting a column, pedestal or \"' ,; ... ,) supporting a column with steel base jlL~ ' section shall be measured at location deC! l: 422.8.5 (3).
Association of Structural Engineers of the Philippines
CHAPTE R 4 - StruclUral Concrete
422.8.6.2 ShenT strength 01" structural plain conc rete footings in the vicinity of concentnucd loads or react ions shall be governed by the more severe of two conditions:
J.
Beflln actioll for footing. with a cr il ic~1I section extending ill H pl
,I
2.
Two·way <1ctiol1 for r~)(Jting. with 11 critical secti{J\1 perpendicular to plane of footing and l
422.J0.4 Prct:;:lst mcmbers sh311 he adcquiltcly bri.lced and suppol1ed during erection to ensure proper alignment and siructllml integrity until pcrmanent connections are completed. 422.1) Plain C{)ncrete in Earthquukc·Rcsisting Structures
422.1 1.1 Stl1lctures design ed for earthquake induced forces in regions or high scislIlic risk or assigned to high sc i~mi c performance or design categori es. e.g. zone 4, shall not have foundation elements of slnicturaJ plain concrete, except as follows: I.
422.8.7 Circular or regular polygon shaped concrete columns or pedestal s shall be permitlcd ( 0 be (reated as squa re members with the same area for location of crilical sections for moment and shear. 422.8.8 Factored bearing load, Bu, on concrete at contnct surface between supportillg and supported member shall not exceed design bearing stre ngth, ¢B'I> for eilher surface as given in Section 422.6.5.
supporting cast·in·place reinforced conc rete or reinforced mas onry w(llls arc permitted provided the foo tings are reinforced longit udina lly with not less than two continuous reinforcing bars. Bars shall not be small er than 12 111m diameter and shall have a 10lal area of not less thall 0.002 times the gross crosssectional area of the footing . Continuity of reinforcement shall be provided at comers and intersections;
422.9.1 Plain conc rete pedestals shall be designed for vertical, lateraJ .tod other loads 10 which they are subjected.
422.9.3 Maximum factored axial load, p., applied to plain Concrete pedestals shall nOI exceed design bearing strengt h, ¢B", given in Section 422.6.5.
For detached one· and Iwo·family dwellings three stories or less in height and constructed with stud bearing walls, plain concrete footings without longitudinal reinforce ments supponing walls and isolated plain concrete footings supponing columns or pedestals arc permitted;
2: Fm all other Structures, pJain concrete footings
422.9 Pedestals
422.9.2 Ralio of unsupported height to average least lateraldimension of plain concrete pedestals shall not exceed 3.
4·135
3.
For detached one· and two-family dwellings three stories or less in height and constructed with stud bearing walls, plain concrete fou ndations or basement walls arc pClluitled provided lhe wall is nOl less (han 190 nun thick and retains no more than 1.2 111 of unbalanced fill.
422.10 Precast Members 422.10.1 Design of precast plain concrete members shall consider all loading conditio ns from initial fabrication to completion of th e structure, including form removal. storage, transportati on and erection. 422.10.2 Limitatio ns of Section 422.3 apply to precast members of plain concrete nOL only (0 the final condition but also during fablication, transponation and erection. 422.10.3 precast members shall be connected secu rel y to transfer all lateral forces into a structural system capable of resisting such forces.
National Structural Code of th e Philippines 6
1h
Edition Volurne 1
4· 136
CHAPTE R 4 -. Structural Concre te
DUCTILE STEEL ELEMENT. An
CkIllCIl' •. ::,
" 'cnsile
lest cJongillioll of ilt least 14 percellt and 1'1'11:" 'ion '!1 area of at least 30 perccnt. A steel CICll\t'1l1 . . \' I i;'g th e requiremcnts or ASTM AJ07 shall he (':oll sili c.:!. ...~i: ~ ti le. E DGE DISTANCE. The di s lHll tC from tl1(' ('che of the conc rete surface to Ih e center of the nearest anc! ll)! :
423.1 Dcl1l1itiOIl' ANC}fOH A stcel element either cast into co ncrete or post·inslallcd into a hardened concrcte mcmbcr und uscd to transmit app li ed loads, including headed bolts, hooked bolts (J- Or L-bolt) , hetl(jed studs, expansion unchors, or undercut anchors.
ANCHOR GROUP. A
number
of
anchors
of
approximatcly equal effective e mbedment depth with each anchor s pnced lit less than 311 tt frolll One or more adjacent anchors when subjected to tension or 3£.'0/ from one or more adjacent anchors when subjec ted to shear. Only (ho se anchors susceptible to the particular failure mode under investigation shall be included in the group.
ANCHOH
PULLOUT
STRENGTH.
The
,treng.h
correspo nding 10 the anchoring device or a major component of the device sliding o ut fro m th e concrete withollt breaking out a sub stant ial portion of the surrounding conc re te.
ANCHOR RErNFOHCEMENT. Reinforcemen. used
'0
transfer the full design load from the anchors into the structuralmcmber. Scc Section 423.5.2.9 or 423.6.2.9.
ATTACHM ENT. The SlruClUral asse mbly. eXlernal.o .he surface of the conc reLe, that transmits loads to or receives load s from !~Ie anchor.
BHITTLE STEEL ELEMENT. An elemen! wi.h a .ensile {cst elongation of less than 14 percent, or reducti o n in area
orIess .han 30 percen •• or bo.h . CAST·IN ANCHOR. A headed bol •. headed slUd. or hooked bolt inst alled befo re plac ing concrete.
CONCHETE IlREAKOUT STRENGTH. The Slreng.h correspondi ng to a volume o f concrete surrounding th e anchor or grCllp of anc ll ors separating from the member.
CONCRETE PRYOUT STRE GTH. The slreng.h con'esponding to formation of a concrete spa ll behind shon , stifr a nchors displ,lced in the direction opposi te 10 the applied ~hca r force.
DISTANCE SLEEVE. A sleeve .hal encases .he ccn.er part of an undercut anchor, a torque-conlrolled cApansioLl anchor, or a di splacemen t-controlled expans ion anchor, but does nOl expand.
EFFECTIV E EMIlf;DMENT DEPTH . The ("'crail
EXPANSION ANCHOn. A post-in~la ll ed :tndHlr, in·W l1ed imo hardened co ncrete that tran sfers load s It ) :H r' lIi:, the co ncrete by direct bearing or friction or bo;;;. ;:-::I,;:I.!;ion anchors may be torque ·controlled, where tht ,- ,.j,a lisi,.Hl is achicved by a to rqu e acting a ll the scrc\'.' 1)1' holt; or displacemenl-comrollcd, where the expnnsil .j ,;", adlicved by impact forces acting 011 a slee ve 01 !,jll!' and the expansion is cOlllro ll cd by the length of trav ri Ld (1 )(: skeve
or plug. EX I'ANSION SLEEVE. The ou 'er pOri "I' "" ""I'",,·';on anchor lhal i ~ forced outward by the cent c! p.t:!, l·illi, l by applied torque or impact, to bear against (Iii.: ~.j(h:~ oj the predrilled hole. FIVE PEH CENT FRACTILE. A s' a'iSlic,,!
Inill
Il 'Mlling
90 perccnt confidence that there is 95 percellt r.ll hiJ hilil y of the actual strength exceeding the nominal strcllt:lil .
HEADED STUD. A steel anc hor confnUli ll!! to the requirements of A WS D 1. 1 and affix.ed to it F !;;!< or si milar stcel attachment by the stud arc welding III ,(·!·::S before ca sting. HOOKED BOLT. A casl -in ancho r ancholi't! 111::1111" by bearing of .he 90·degree bend (L·bol,) or -Ild (J-boIL) against the concrete, at its cmbed,k.1 (:lid. ;~ lId
I"" :. ,. "
ha ving a mi nimu m ell of 3dn .
POST·INSTALLED ANCIIOR. All alld ,.
',,, ::.:'
Ilardencd concrete . Ex pan~i on anchors ;!lld ancllors arc ex. PROJECTED AREA, The area
011
ill
lIIHh,.. rcut
the fr('c ~'ud :';' I' of the . ;(: Il
concrete member thaI is llsed to represent Ill;, th c ass umed rectilinear failure surface.
SIDE-FACE BLOWOUT STRENGTH .. '., anchors with deeper cmbedmcnt but t h ij~L, :.! .. ,: ' .'. -: corresponding to concrete spalling Oil tim side :-,1((; mOUlni
Association of Structural Engineers of the Philippines
CHAPTEn 01 ..
Ihe ~mbcddcd head while no major bn:i1koul occurs al tile lOp (;OJ)(.'fC le slIrfal·c. SPECIALTY I NSEnT. !'redesigned and prcrabricall:d
cast-in HIU.:h ol"s spccificillly designed for aUachmc.nt of boltcd 01' sJolwd l· orlllcl·til)lls. Speciall y inscl1s arc oftt::n used for handling. transportation. and erectioJl. but arc aiM) u$cd for
StfUCtt)f(11
Concre te
4 · 13('
423.2.4 I_oad i.I PI>licmions that arc predominantly high l'ye le fatigue or impact Jo'lds are nOI covcred by thi s secti oll.
423.3 General Ucquircmcnt s 423.3.1 Anchors and an c hor group s sh.1I1 be design ed for critical dTccl:-. of f<.lc lon::d loads as de termincd by clastic analysis. Plastic analysis ~Ipproaches are permitted where nominal st rength is controlled by ductil e steel elcments. prov ided th;1I dcformmional co mpiUibility is taken illlo account. 423.3. 2 The des ign strength of anchors sl)<111 equal or exceed Ih e largest required st re ngth colleUliltcd from the applicable load co mbinati on s in Secti oll 402 . 423.3.3 W he n ancho r design includes earthquake forces for structures ass igned {o seism ic zones 2 or 4, the <\dditional requirements of Sectio ns 423.3 .3. 1 through 423.3 .3.6 shall app ly. 423.3.3.1 The provisions of this sec ti o n do llOl apply 10 the design of anchors in plastic hin ge zones o f concrete structures under earthquake forc e~.
423.2 Scope 423.2.1 This secti on provides design requireme nts for anchors ill concrete used 10 transmit structural loads by means of tension , shea r. or a combination of tension and
shear be tween : L
Con nected struc tu ral clcments; or
2.
Safely ~rc l a ted attachments and structural element s;. Safety leI/cis specifi ed are intended for in -service condi ti o ns, rathe r than for shon-lcrm handlin g and construction conditions.
423.2.2 Thi s section applies to both cast-in ancho rs and post -installed anchors. Specialty inserts. through bolts , multipl e anchors connected to a single steel plate at the. embedded end of the anchors. adhesive or grouted anchors. and direct anchors such as powder or pneumatic actuated nails o r bolts, are not included. Reinforcement used a $ part of the embedment shall be designed in accordance with other pariS of Ihis section . 423.2.3 Headed stud s and headed bolts ha vi ng a geometry that has been de mo nstrated to resull in a pu ll out strength ill unc nlckcd concrete equa l or exceeding I .4NI , (w here Np is g ive n by Eq . 423 -15) are include. Hooked bolts th "t have" geome try {ha t has been demonstrated to res ult in a pu ll o ut strength w ithout the bene lit of frict ion in unc racked concrete eq ua l or exceeding 1.4NI' (where NI1 is given by Eq. 423-16) are included. Post-installed anchors th at meet the assessme nt requirements of ACI 355.2 arc in cluded. The suit abili ty of the pos{~illsta!!cd anchor for use in concrete shal l have been demonstrated by the ACI 355 .2prequ alifi cation tests.
423.3.3.2 Post~instal!cd structura l anchors shall be. q ualified for use in cracked conc rete and shall have passed the Simulated Seismic Test $ in accordance with ACJ 355.2. Pullout strength N" and steel st rength of th e anchor in shear \1$'1 shall be based on the results of the AC I 355.2 Simulated Seismic Tests. 423.3.3.3 The a nchor design s trength assoc iated with co ncrete railure modes shall be taken as O.7S¢N"
or
423.3.3.5 Instead Section 423.3.3.4, the aHac hmcllt Ih31 the anc ho r is connecting to the struc ture sha ll be designed $0 thal the att achment will undergo ducti le yieldin g at a force level corresponding to lInchor rorces no greater than the design st rength of ancho rs specified in Section 423.3.3.3. 423.3.3.6 As an alternative to Sec tions 423.3.3.4 and 423.3.3.5, it shall be permitted to take the design strength of the anchors as 0.4 times the design st rength determined in
tll
National Structural Code: of tile Philippines G Edition Volume 1
4·I:m
CHAPT H~
4 ·- Structural COI1(;Ielc
accordance with Secti on 423.3.3 .3. For the ,mehor.Ii of SlUt! bearing wall s, it sh;J!I be permitted to take the design strength of the anchors as 0.5 times (he desi gn strength det crm ined i ll
for posl-i nswlled anchors when used in concrete with J,.' greater than 55 MPa. 423.4 General itequircments for Strength of Anchors 423.4. 1 Strength design of anchors shall be based either on computation using design models that satisfy the requirements of Secti on 423.4 .2. or 0 11 tes t eva luat ion using the 5 percc nt rraclile of les t result s for the following:
1.
Steel strength of anchor in tension (Section 423.5.1);
2.
Steel st rength of anchor ill shear (Sec tion 423.6.1);
3.
Concre te breakout strength of anc hor
in
tension
(Sect ion 423.5.2);
4.
Concrete breakout
strength
of anchor
in
shear
(Sec li on 423.6.2); 5.
Pullout st rength of anc hor in ten sion (Sec tion 423.5.3);
6.
Concrete side· face blowout strength of anchor in tension (Section 423.5.4); and
7.
Concrete pryollt strength of anchor in shear (Section
consideration oj: (Nu,' eithe r ¢N'h or .pVCf'.\:
OJ'
fjJII,·bx' and l'it hl'f ¢V
cp
bm h N,,,, and \','" (l rc prese nt interaction crfccts shall be considcwd in accordance Witl;
423.4.1.3 Whe n Seclioll 423.4.3 .
423.4.2 The nominal strength for any anchor or gro up of anchors shall be based on design models that result in predictions of strength in substanti al Clgrcelllcnl wit h reS ults of comprehe nsive tests. The materials lIsed in the tests shall be compati ble wit h the materials used in th e structu re. The nominal strength shall be based 011 the 5 percen t fnlctile of the basic individual anchor strength . For nomin.l l strengths related to concrete strength. modifications for size effects, the number of anchors, the effects of close spacing of anchors, proximity to edges, dep th of the concrete member, eccentric loadings of anchor group~. and presence or absence of crack ing shall be taken into account. Limits 011 edge distances and anchor spacing in the design models shall be consisten t wi th the lests [hill veri fied the model. 423.4.2.1 The effect of reinfo rcemen t provided to restrain the conc rete breako ut sha ll be permitted 10 be included in the design mod els used to satisfy Section 423. 4. 2. Where anchor reinforceme nt is provided in accordance with Secli ons 423.5.2.9 alld 423.6.2.9. o<1lclllalioll of Ihe
concrete breakout strengt h in accordance wi th Secti ons 423.5.2 alld 423.6.2 is 1101 requ ired . 423.4.2.2 For anc hors with diameters not exceedi ng 50 ITIm, and tensile embedments not exceeding 635 mm in
depth, the concrete breakout strength requirements shall be co ns idered satisfied by [he design procedure of Sections 423.5.2 alld 423.6 .2.
423.6.3).
In additi on, anchors shall satisfy th e requi red edge di stan ces, spaci ngs, and thi cknesses to p;ecl ude splilting failure, as required in Section 423.8. 423.4.1.1 For th e design of anch ors, except as required in Seclion 4 23.0.3 . ¢N,, ?: N u"
(423 - 1) (423-2)
423.4.3 Resi stance to combi ned tensile and shear loads shall be considered in design using un interaction expression that re sults in co mput ati on of strength in subs tantial agree men t wi th results of comprehensive tests. This requirement shall be considered sati sfied by Section 423.7. 423.4.4 Strengt h reduc ti on factor ¢ for anchors in concrete shall be as follows when the load co mbi nat ions Section >102. nrc used: I.
Anchor govcrned by strength of a ducti le steel clement
423.4.1.2 III Eq . (423·1) and (423·2) . ¢N" and ¢V" arc Ihe
lowest design strengths determined fmlll all appropriate failure. modes. (W" is the lowest design strength in tension of an anchor or group of anchors as determined from considerati on of (>N.1(II fliNt"', either ¢N.,'" or t/JNstJK' and either ¢Nrh or ¢NCb&' ¢V" is the lowest design strength in shear of an anchor or a group of anchors as determined from
2.
a)
Tension loads ........ ..
b)
Shear loads
...... .................. .......0.75 .. ............................. .....0.65
Anchor governed by strength of a brittle steel element a) Tension loads ..
..................... ..... ....... 0.6)
b) Shear loads .....
................................. 0.60
Association of Structural Engineers of the Plli1 ippines
.~
CHAPTEH
3.
Andwr governed hy conc rete breakout, side-face blowuul. puiloUl. or pryollt strength
Condition A :I)
b}
Conditioll B
0.75
Shear load ...
0.70
Tension loads Cast-in hC
<1 ..
St ructurell Concret e
423.5.2 Concrete llreakouf Strength of Anchor in
423.5.2.1 The nomill:.!l con cret e break o ut strength. N,-b or N. bg , of i.l single anchor or group of anchors in te nsion shall
not exceed I.
r or
(423·4 ) 0.75
0.70
Posi-instctlled anchors with caiegoTY as determined (rom ACI 355.2
2.
Category I (Low sensi ti vi ty to insta ll.lI ion and high reliability)
0.75
Category 2
0.65
0.55
055
0.45
For a group of anchors (423· 5)
0.65
(Mediulll sensitivity (0 installation and medium reliability)
Category 3 (High se nsitivity to j nstallation and
t 39
Tension
IWi.tdcd bolt s. or hooked
. bolts
~.
lower reliability) Condition A appl ies where supplementary re inforcement is present except for pullout and PTYOUI st rengt hs . Condition B applies whe re supplememafY reinforceme nt is nol present , and for pullout Of pryou t strenglh .
Factors IPu,N, Vlcd,N, Iflr,N, and '1'ep,N are defined in Sections 423.5.2.4.423.5.2.5,423.5.2.6. and 423 .5.2.7, respectively. ANc is the projected concrete failure area of a single anchor or group of anchors that shall be approximated as tile base of the rectilinear geometri ca l figure that results from projecting the failure surface ou tw ard 1.511,,/ from the ce mcrlines of the anchor, or in the ClISe: of a group of anchors, from a line through a row of adjacent anchors. AN,' shall not exceed nANn" where n is th e number of tensioned anchors in the group. AN,,, is the projected concrete failure area of a single anchor with an edge distance equal to or greater th an 1.511 rf
(423-6) 423.5.2.2 The basic concrete breakou t strength o f a single anchor in tension in cracked conc rete , Nb , shall not exceed:
7' ilf'-' r
Nh ~K , A,,J
423.5 Design Requiremcnts for Tensilc Loading
r;
(423-7)
where
423.5.1 Steel Strength of Anchor in Tension 423.5.1.1 The nominal strength of an anchor in tension as governed by the steel, N~ , shall be evaluated by calculations based on the properties of the anchor material and the physical dimensions of the anchor. 423 .5.1.2 The no minal st re ngth of a single anchor Of group of anc hors in tension. N 1fI • shall not exceed
N'(I = nAn·.N/ufI)
(423·3)
where 11 is the number of anchors in the group, A st,N is the effec ti ve cross -sectional area of a single anchor in ten sion,
mm 2, alld /Ilm shall not be taken greater than the smaller of
1.91,., and 860 MPa.
kc kc
10 for cast-in anchors; and == 7 for post -installed anchors.
The value of k, for post-installed anchors shall be pennilled to be incfeased above 7 based on ACI 355 .2 pfoductspccific tests. but shall in no case exceed to. Ahcrnativcly. for cast-in headed s tuds and headed bolts wi lh 280 min::; hcf~ 635 mm. Nb sll3ll not e xceed
Nb ~ 16A ff: hJ '"
(423-8)
423.S.2.3Where anchors arc located less th an l .5hcf from three or mOfe edges, the value of htj used in Eq. 423-4 through 423-11 shall be (he greater of c o.mll /l.5 and onethird of the maximum spacing between anchors within the group.
National Structural Code of the Philippines 6'" ledition Volum e 1
4·14 0
1,.
CHAPTE H tl .. Struc lul a l COnCre !(>
423.5.2 .4 T hl.' Illodificmion fac lor fo r anc hor groups loaded cc:r:r nlricall y in le ns ion. Iflu.N, sha ll be computed as: (42)-9)
blll VI.·.·.Ns hall not be taken greater than 1.0. If the 100Iding o n
T ht· cracki ng in the l'nllcrctc shull he co ntrolled by flex ural reinfo rcement. dist ributed in accordance with Section ' 410.7.4. or eq ui valent (Tack con tro l shil ll he provided by t"{lIlfi ning reinforceme nt. 423.5.2.7 The modificClt ion f"iICWJ" for posl·ins1:.ilJcd anchors designed for uncrat' kcu concrete in accordan ce with Scctioll 423.5 .2 .6 wi tho ut supplementary reinforceme nt 10 control sp lillin g. IfI(P.N. sha ll be comp uted as ;i~;lows usin g [h e c rit icii. dis tance Cat as lkfincd in Section 423.8.6.
If e a,mil( ?
Car
thcn
V'",."" = 1.0
(423- 12)
In the case where eccentric loading exists aboul two axes . the modi fi ca ti oll fac tor, Vlu.N. shall be compu ted for each axi s indiv idually and the product of these (actors used as V/~'.N in Eq. 423·5. 423.5.2.5 Th e modification factor for edge effec ts for
si ngle anc hors or anchor groups load ed ill le nsio n, shall be co mputcd as
th e ll
Jf
C(I,mil,
<
Vlcd,N=
1.0
Ifltd,N.
(423- 10)
1.5h rf
t Ilen
III "f'
.4.,.,
e = O.7+0.3~~~I 51 •
(423- 11)
It'f
423.5.2.6 For anchors located in a reg ion of a concretc member where analysis indica te s no c racking a t service load levels, the foll ow ing modificill ion fac tor s hall be
penni tted : VIr,,.. = 1.25 for cast·in anchors; and VI",\' :::: 1.4 for post-installed anc hors, whe re the val uc of k, uscd in Eg. 423-7 is 7. Where the va lue of kc used in Eq. 423-7 is taken from the ACI 355.2 prod uct evaluation rcpon for post-installed ~lI1 cho rs qual ified for lISC in hoth c racked and unc rac ked concretc, Ihc vallics of kc and V'c-.N shall be based all the ACI 355.2 produc t evaluation reporl. W here t h L~ v
(,123-13)
but II'(p,Nd eten n in cd fr olll Bq. 423- 13 shall flot be taken less than 1.5h,,! Ie", . wherc the c ritic a l dista nce ell( is defined in Scction 423.8.6 . For all othcr cases, incl uding c
1fI'l"1\'
shall be
423.5.2.8 Where an addi tiona l pl ate or washer is added at th e head of the anc hor, it shall be permi tt ed to calculate the projected area of thc fa ilure surface by projec ting the fa ilure surfacc outwa rd 1.5h r/ from the e ffec tivc perimete r of the plate or washcr. The effec ti ve peri meter shall not exceed the valuc at a sec ti on projecte d outward more than the thickness of the was her 01" plat c from the outer cdge of the he'ld of the anchor. 423.5.2.9 Where anchor reinforcement is developed in accordance with Section 4 I 2 on both sides of the breakout surface, the design strength o f the anchor reinforcement shaIl be pemlincd to be lI sed in stead of th e co ncrete breakout strength in determining ¢Nn. A strength TI'duclion fac to r of 0.75 s hall be used ill the dcsign of lilt: anchor re info rcement. 423.5.3 Pull oul S trength of An ch o r ill T ellsi o n 4 23.5.3.1 The llomin;11 pull o ut strength i ll te nsi on , N"", s hall Ilot exceed
where
qlc,l'
is defined in Section 4 23.5.3.6.
Wh en ana lysis indicates crackin g at service load lc:vels, lI' c,N s hall be taken as 1.0 for both cas t-in anchors and postinstall ed anc hors. Pos t-installed anc hors shall be quali fied for usc in crac ked concrete in accordan ce with ACr 355.2.
Association of St ructura l Eng ineers of the Philippin es
or a ~ illtk . ~ic h or
CH/,Pi t: .;
423.5.3.2 For post ·inswllcd expansion and undercut iUH.:hors, (he values IIf Nf • sh;11I he based 011 the 5 percen l fracti lc of results of les ts perfo nncd and evaluated Hccof(l ing 10 AC I 355.2. II is not permissib!e to c alc ul ate the pull o llt strength in tcnsion fo r such anchors . 423.5.3.3 For singlc (,'
li hnll be permill cd (0 evalu
;lOchors sllsceptihle 10 nol exc..'cc
N
'''r.
it
'Ilk- rae!.: blo\\'OIII railu re N" ,_~ sllilll
.1") N = I + ·_······ (
., It- I
6{'
(42) ·I X) ,.11
,01
where s is [he distance be tween the otHer anchors al() ng tlie edge, ,l1le! N ,II! is obtained from Eq. 423 *17 wit ho ut modi fi cati on for a pe rpendkular edge d istan ce. 426.6 n csing Requirements for Shcm' Loading
423.6.1 Steel S trength of Anchor in Shear 423.6.1.1 The nominal strength of an anchor in shear as governed by steel. \/",. shall be evaluated by calculalions based on thc properlies of Ihe anchor material and the phys ic'll di Ille nsio ns of the anchor.
(421- 15) 423.5.3.5 The pull out stre ngth in tension
or
a sin g le hoo ked bolt. Nt" for LJ S~ in Eq . 423* J 4 shall not excee d
423.6.1.2 Th e no m inal strengt h o f a single anchor or gro up of' anchors in shear, \/."" shall not exceed ( I ) thro ugh (3) :
I.
For cas(*in headed stud ancho r
(423·16)
423.5.3.6 For an ancho r located in a region of a concrete membc r where analysis indicates no c racking a t service load levels, the following modi fi cat ion fa(,'tor shall be pennilted VIc,/'
(423 · 19) where II is the Hu mber of anchors in the group, A .... 1, is {he effec tive cross*secli ona l area of a si ngle anchor in shear, mm2, and!."., shall nOI be taken grealer Ihan the
s malle r of 1.9[,." a nd 860 MPa.
2.
= 1.4
For casl*jll headed boh and hooked bolt anchors and for posl*installed anch ors where sleeves do not extend through the shear plane (423-20)
Where analysis in dicates cracking at service load levels, Iflc.p shall
be taken as 1.0.
where
II
is the number of anc hors
ill
the group, A ~ <"y is
the erfective cross*sccti otlal area of a si ngle " lIchor in
shear,
423.5.4 Concrete Side-Face Blowout Strength of a Headed Anchor in Tension
and };'1<1 shall !lot be taken gre ater th an th e
smaller of 1.9};" and 860 MPa.
3. For a sin gle headed anchor with deep e mbed ment close to an edge (h.1 > 2.5c(,,) , the Ilomi n
2 1111n ,
For post-installed an chors where sleeves ex tend through the shear pl ane, VJ
Eq .
423·20
shall
be
(423·17) 4 23.6.1.3 Where anchors arc used wilh bu ill -up grout
If en1 for the single headed anchor is Ic.."s than Jell" the value of N. b shall be lIlultiplied by the faclor (I +(1121(.'",)/4. where 1.0 S; en/cal ::; 3.0.
pads, Ihe nominal strengthS of Section 423.6. 1.2 shall bc multiplied by.\ 0.80 factor.
423.5.4.2 For mulliple headed an cho rs wi lh deep embedment close to 3n edge (II!,! > 2.5cll l) and anchor spacin g less th an 6c a f, the nominal strength of thos e
National Structural Code of the Pili li ppines 6
lil
Eclition Volume 1
-, "
1
423.6.2 COlltTcl<' Hn' a kou ( St r cn~th of AndlOr ill Shea r 42],6,2, I '1'11\' !lomina! connell' hrc
I.
nitiL."al. and all of Ihe s heil!" ~hall he assumed 10 be ca rri ed hy Ihis nilica l anchor row "lo ne . 423.6.2.2 The haf\ il: (.'Ollcn:tl' hn'a knu t o;: trcngth in shear of a sin gle anc ho r in Cfilcked COllncte, 1'". shall not e xceed: (423 -24)
For shear f'on:c perpendi clliar 10 th e edge on a sin gle anchor
A,.
(42J.2 1)
V.I, = -A '-. '" '" "I V 'f' ",{.I' 'f' ,.1" '" ".I' " H ..
2.
Por she Hr ro rce perpendicu lar to Ih ~ edge o n anchor.-;
iI
4.
I,.
= h'f
I...
= 2d" for torque-controlled ex pan sion :tllchors with !l distance sleevc separated from expansion sieev(.. and in no e'lse shall I,. exceed 8£1" in all c
group (If
(42).22)
3.
vi.here I,. is th e load -bearing length of the au t hor fe' ., 'l e
For shear force parallel 10 an edge. V,." or 1"'/;K she, ll be prnnilted 10 be twice thl' v,lluc of the shear force determined from Eq. 42l-2 1 o r 423-22, respectivcly. wi lh (he. Sh Cili' force aSS trrn l~<..I (0 ,1(;1 pc'~rpc ndi cular to (he edge and with 1,II"dy taken equa l (0 1.0. For ilm.: hors loc a(l~d at a c"Orner, Ih e li rn itine nomin al concrete bn~lIko Ui strength sha ll be delerJ11ine~j for cac h edge, and the minimum va illc sh all be used.
lo r andlOfs wit h a consl;UH stiffness over the full length o f embedded sec tio n. :.;uch as he,h ir;l stud s or post-in sta lled anchors wit h one wInd;,,, she ll ovcr full length of the embedmcnt de pth;
r-or cast-i n headed st uds, headed hoils , Or hooked bolts OWl ;ire cOlltinuously we lded to s leel nua chmcnts having a rni nimuill th ickness equal to the greate r of I () 111m and half of the an chor diam eter, the bas i<' co ncrete breakou t stre ngth in shear of C! sin gle anchor I \ crac ked concrete. VII> shall not exceed : 423.6.2.3
\I,.
Factors '1'.·, .1'. Vlr,I.\ ', VIr. I'. and '1III.v are defined in Sec ti o ns 423 .6.2.5.423.6.2.6, '123.6.2.7, and 423 .6.2.8, respeclivcly. \I" is the basic co nc rete brea kout stre ngth va lu c for a si ngle anchor. A I',· is the projected areH of the fai lure surface on the s ide of the conc rete member a l its edge for a single anchor o r a group of ancho rs. It shall be permitted to e.valuate All, as the base uf a tru ncated half pyra mid projec ted on the side face of the me mbe r where the top of the ha lf pyramid is gi ven by (he ax is of the anchor row selected as c ri tical. The value of C-li shall be taken HS the di stance from the edge 10 this axi s. A ve shall not exceed AI,cOl where n is the number of anchors ill the grollI'.
A vn, is the projec ted area for a single anch or in a deep memb er with a di stance from edges eq ual or greater than 1.5ca ! in the directi on perpe ndicular 10 the shear force. It shal! be permitted to evaluate AI'n' as the bnse of a ha lf pyramid with a side length pamllel to the edge of 3c", and il depth of 1.5c;o1 A \'r.o
= 4 .5«('(I/)~
=066(1:rJd~Aff(C."Y'
(423·2:> j
where I.. is defin ed in Sec tion 423.6.2.2. prov ided that: I.
For grou ps of anchors. (he strength is dctermined bas...,) on the strength of {he row of anchors farthest from I t,:
edge: 2.
Anchor spacing. s, is not less than 65 mm .: and
3.
Re inforcement is pro vided at the corners if Col'S 1.511,":"
423.6.2.4 Whcre an chors arc inO uellced by th ree or 111m,'. e dges, the va lue of e(l} used in Eqs . 423 -23 through 423 - 2~) shall not exceed th e greatest of: c,JI.5 in either dirccli O!; , h(l 11.5; and one ~ third of the maximum spaci ng bctwc(;:ij anc hors within th e group. 423.6.2.5 The modifi cation faClOr fo r anchor grOt!p . loaded ecccntric<.l ll y in shc ar.lf/rc. "\ shall he compu ted a~::
(423·26)
(423-23)
\Vhcre anchors are loe,lted at vnrying distances frol11 the. edge and !he anchors arc ' . . e lded to the attach ment so as to di stribute the force to all anchors, it shall be pennitleo to
btu V'n."shall not be l
evaluate the strengt h based on the dista nce to the farthest row of an cho rs frolll the edge. In this case, it shall be permi tted to base the value of CII / on th e di stance from th e edge to the nxi s of the fart hest anchor ro w that is selected as
[f the loadi ng on .111 an chor group is such that on ly some anchors are loaded in shear in the sa me direction. {,'.Jy those anchors th at arc lo aded in shear in the sa me dii :[' ; .. 1 shall be considered when determining th e eccentri ci ty ui
Associa tion of Structural Engineers of the Pllilippines
for usc in Eq. 423-26 and for the calculation of V,b/: in Eq.
423.6.3 Concrete Pryout Strength of Anchor in Shear
423-22 423.6.2.6 The modification factor for cdge effect for a single anchor or group of anchors loaded in shear, VI,.,!.\' ' shall be computcd as:
423.6.3.1 The nOlllinal pryou( strength, V"I' or V,I'!: shalj no! exceed: j.
For a 5i nglc anchor (423-30)
thcll
W~d,I!=
1.0
(423-27)
2.
For a group of anchors (423-31)
If Ca2 < 1.5to' where
(423-28) k,p:= 1.0 for 11'1< 65 mm.; and k,.p = 2.0 for h,/2:. 65 423.6.2.7 For anchors located in a region of a concrete member where analysis indicates no cracking at service loads, the following modification factor shall be pennilted: /flc.v :::
1.4
/flcY
Wc,\'
Ncb and N cbg shall be determined frorn Eqs. 423-4 and 4235, respectively. 423.7 Interaction of Tensile and Shear Forces
For anchors located in a region of a concrete member where analysis indicates cracking at service load levels, the following modification factors shall be permitted: WcY
mill.
J.O for anchors in cracked concrete with no supplementary reinforcement or edge rcinforcemcnt smaller than a l2mm diameter bar; =J.2 for anchors in cracked concrete with reinforcement of a 12 111111 diameter bar or greater between the anchor and the edge; and ::: 1.4 for anchors in cracked concrete with reinforcement of a 12 mm diameter bar or greater between the anchor and the edge, and with the reinforcement enclosed within stirrups spaced at not more than 100 mm. :::
Unless determined in accordance with Section 423.4.3, anchors or groups of anchors that arc subjected to both shear and axial loads shall be designed to satisfy the requirements of Sections 423.7.1 through 423.7.3. The value of ¢N'I shall be as required in Section 423.4.1.2. The value of ¢VI shall be as defined in Section 423.4.1.2.
423.7.1
Vlh,V
- J1.5C., Il"
(423-29)
but Wh. vshall not be taken less than 1.0. 423.6.2.9 Where anchor reinforcement is either developed in accordance with Section 412 Oil both sides of the breakout surface, or encloses the anchor and is developed beyond the breakout surface, the design strength of the. anchor reinforccment shall be permitled to be used instead of the concrete breakout strcngth in determining ¢VII. A strength reduction factor of 0.75 shall be used in the design of the anchor reinforcement.
2:: Nlw '
423.7.3 If V"" > O.2¢V" and N,," > O.21N,,, then
!i..",_ + N ,,, ¢N"
shall be computed
'fh.y -
rfNlI
423.7.2 If N,," S O.21N", ihen full strength in shear shall be permitted: ¢VII 2: V,w.
423.6.2.8 The modification factor for anchors located in a concrete member where ha < I.Seal> as:
If V,," S O.2¢V", then full strength in tension shall
be permitted:
~ 1.2
(423-32)
¢V"
423.8 Required Edge Distances, Spacings, and Thickness to Preclude Splitting Failure Minimum spacings and edge distances for anchors and minimum thicknesses of members shall conform to Sections 423.8.1 through 423.8.O, unless supplementary reinforcement is provided to control splitting. Lesser values from product-specific tests perfornied in accordance with
ACI 355.2 shall bc permitted.
423.8.1 Unless determined in accordance with Section 423.8.4, minimum center-to-center spacing of anchors shall be 4d(l for untorqued cast-in anchors, and 6d(l for torqued cast-in anchors and post-installed anchors. 423.8.2
Unless determined in accordance with Section 423.8.4, minimum edge distaaces for cast-in headed anchors that will not be torqued shall be based on specified
National Structural Code of the Philippines 6~h Edition Volume 1
t:ovcr rC(lu in'tJlc llI S for rL'infIJlTC llh!ll t in St't'l ion 407.X. For t:;lsling hC
UnderCUI anchors .... ... .. ... ....... .. .... .. ...... ..
SECTION 424 ·-~:?sl ALTERNATE DESIGN METHOD , 424,1 Notations Some notat io n defi nitiolls arc modi li ed from thost" in lh~~ main body or th e t'otl e for ~pccific lise in Ihe :q)plication of' Sec (ion 424. ;\J:
A,.
Af A}
... 6d"
Torque-controll cd anchors ...... ... ......... ..... ... .... . 8d" Displaccmelll-controlJeu ,.II1CI1OI"S ....... .. . ..... IOd" 423.8.4 For a nc hors where install at ion docs not prod uce a s pl itti ng forcc a nd tha t wi ll remain ulltorqued , if the edge distallce or spacing is less th an those speci fied in Sections 423.8.1 to 423,8.3, calculations sha ll be performed by substituting ror d" a smaller va lue d'" (hal meets the requirements of Sections 423. 8, I to 423.8 .3. Calc ulated forccs applied to the anchor shall be limited to th e va lues corresponding to an anchor havin g a diameter of cI'O'
h"
b" d E,. E,
j',.
""1
423.8.5 The va lue of for an ex pansioll or undercut posi- installed anchor shall not exceed the grealcr of 2/3 o( thc member thickness and th e member thi ckn ess minus 100
mm. f, 423.8.6 Unless determined from tension tesls ill accordance with ACI 355.2. the cri tical edge distance, clI(" shall nol be takcn less tha n:
f, M /I
U ndcrcut anchors .... Torque~con troJled
2.511"
anchors
.... 4h(,/
Displacement-controlled an c hors ...
N
. 4h~!
423.8.7 Proj ect drawings and project specifications shall specify use of anchors with a minimum edge dist ance as assumed in des ign. I'
423.9
In s lal1 ~lti o n
of Anchors
423.9.1 Anchors shall be in stalled in accordance with the proj ect drawings, project spcc ifi cations and/or manufacturer's installation procedures.
a
PI"
= gross an.:a or secti on, mm 2 o f shear rcinforccmclH wit hin a distalH.;c x. mill:! = londed area = maxi mum urea of the portion of Ill'.' ·upponing surface thilt is geomctrica lly si mil ar to and conccntri c with the loaded area = perimcter of critical scction for slabs and footings, mm = wcb width , Of diametcr of circultlr s('.ct in n, mm = dislanc.:c from ext reme co mpressioll flbcr to centroid o( tension reinforcement, mill = modulu s of elasli city of concre te. IviPa. See Secti on 408.6. J : ;:;: modld us o f elasticity of rcinforcement, MPa. Sec Section 408.6. 2 = specified com pressive stren gth of concrete, Mr". Sec Section 405. = square root of specified co mpressive slrength of =
concrete, MPa :::: average spliuing tensile strength of lightwe ight aggregate concrete. MPa. Sec 40.') .?.4 = permissible tensile st ress in reinfort:cm::n; , MP:l :::: specificd yield strength of rei nforcement, MPa. Sec Secti on 403.6.3 = design moment :::: modular rnli o o f elas ti city = £.1/£(, = design axia l load normal to noss :·;eclion occurring si multaneously with Vj to be taken as positi ve for co mpression, negative [or tensioll , and to include effects of tensioll due :(: creep and shrink age = spacing of shear reinforcemen t in dir('ction parallel to longi tudinal reinforce.Jnr.nt , ): 1!: ; :::: des ign shea r stress = permissible shear stress carri ed hy n i: ' ,t.:ir, MPa :::: permissiblc horizonlal shcar strcss. Ml ';( = design shcar force at section :::: angle between inclined st irrups .ntO longia:dina! axis of member = ratio of long s ide LO short side or (;OWT = . .d load or reaction area = rali o of tension re inforcement
=Alb,," Association of Structural Engineers of the Pililippines
CHAP TE R
= stre ng th reduct io n raclOr. Sec Sectio n 4243. 1
<1 --
Strllc!tua! Con:rcte
Jois ts: S he:l r carried by concre te,
1'( .
0.09/]'.
424.2 Scope Two-way slabs Clnd footings: 424 .2.1 Nonprcslrcssc d reinforced concrete members shall be penni tied 10 be. designed using serv ice loads (w itho ut load fac tors) and perm issible serv ice load st resses in acco rdance. with provis ions o f Section 424.
by
Jr. ''"li.
Shear carried by cOll crele, 1',. 1 .. ('/ 12 ) (1+21/3..) but not greater th an
3. Bearing 'o n loaded area l.
0.3!"
424.2.2 For design of members 11 0 ( covered; Sect io n 424, appropriate provisions of thi s code shall appl y.
424.3.2 Tensile stress in reinforce ment It sha ll not exceed the fo ll owing:
424.2.3 All app licable provi sions o f th is cod e [or nonprestressed conc rete, except Section 408.4, shall app.l y to members desig ned by the Alternate Design Met hod .
I.
Grade 275 reinforcement
140 Mr.
2. G rade 415 reinforccment or greater and welded wire fabric (plain or deformed) .... 170 Mra
424.2.4 Flexural members shall meet require me nt s for deflecti on co ntrol in Sect ion 409.6, and requirements of Sections 410.5 through 4 I 0.8 of this code.
3.
424.3 General
424.5 Development and Splices of Reinforcement
424.3.1 Load fHctors and strength reduction fac tors ¢ shall be taken as unity for members designed by th e Alternale Design Method.
424.5.1 Development and splices of re inforce ment shall be as required in Section 412 of this chapter.
424.3.2 It shall be permitled to proportion members fo r 75 perce nt of capacities required by o lher parts of Section 424 when considering wind or earthquake forces co mbined with o the r load s , provided the resulting sect ion is no t less than Ih at required for the combinatio n of dead and live load .
424.3.3 When dead load reduces effects of ot her loads. m embers shall be designed for 85 percent of dead load in combination with the other loads. 424.4 Permissiule Service Load Stresses
For flexural rei nforcemcnt , mlo mm or less, in o ne· way slabs of not more than 4 In spa n but not g reat er th an
200 MPa.
0.50 J,
424.5.2 In satisfyin g requirements of Sectio n 4 I 2.12.3, Mil shall be taken as computed moment ca pacity assumi ng all pos itive moment tension reinfo rcement at the secti o n to be stressed to the permissible tcns il e stress h, and Vu shall be taken as un factored shear force aI the section.
426.6.1 Flexure Fo r investigation of st resses at service loads, straight-line theory for flexure shaH be used with the following ass umptions:
424.6. 1 Strains vary linearly as th e di stance from the neutral axis, except for deep flexural members with overall
424.4.1 Stresses in concretc shall not exceed the foll owing::
depth· span ratios g reater than 215 for continu ous s pans anti
I.
4/5 for simple spans. a nonlinear di stributi on of strain shall be co nsidered . See Section 410.8 of thi s Chapter.
Flexure Extreme fiber stress in compress ion .
2.
Shear' Bcams and olle·way s hlbs and foolings: Shear c"rried by co nc rete,
\Ie ..
......009 JT
, If shear reiuforcement is provided, see Sectiolls 424 .8.7.4 and 424.8.7.5
Maximum shear carri e d by concrete plus shear reinforcemen t,
lie
**.
O.38JT
, For morc detailed calcula!ion of !he shear slress carried by COI\C [\~tc and shear values for lightweight aggregate concrete, see Section 424.8.4. H Desiglled in at:cordi111Ce with Section 408. J 2 of this code.
I',
I When the !iuppor!ing SurfOlCC is wider un all sides 111:111 the loaded ilrC:l. permiss ible bearing stress Oil the loaded area sh:tll be permitted 1(1 he multiplied by ~ 1\ I A, but not more than 2. When the slIr>porting surface
is sloped or stepped , Al shall be permitted to be taken as the area of the lower base of the largest f!1Jslum of a Tight pyramid or cone contained wholly within the support and baving for ils upper base the loaded area, and having side slopes of I vc:rtical-to 2 horizontal.
National Structural Code of the Philippines 6'" Edition Vol ume 1
4 14 6
1
CHAPT U l <'l -. StrucltJraf CO rlCI('!tc
t;
424.6.2 Stn::'ss-slnlin rel ationship or l.:Olil.:rCIC i ~ .. st ra ight linc UIH..I CI' se rvice loads wilhill pC!rmissible sCfvil.'c load su·esses.
torsion shall be taken as 55 pcn.:c nt of thl! v.li u('s givcn in Section 411 .
424.6.3 III reinforced t'oncrclc members. concrete resists
424.8.4 ShCHI' Stress C;lrri ed by COIl<'Tctc
no tension.
424.6.4 It sh all be permitted (() take th e modular ratio, E IE, .. as Ihe nearest who le !lumber (but no t less Own 6) . Excepl in calcu lations for deflec tions , vallie of 1/ for lightwe ight conc rete shall be ass umed to be the s
j
In doubl y reinforced nex ural members. an effect ive modul ar ratio of 2E/£,. shall be lIsed (0 transform 424.6.5
compression reinforcemenl for stress co mpuuH ioll s. Co mpress ive stress in suc h reinforcement sha ll not exceed permissible tensile stress.
424.8.4. J Por members subjec t to shear and flexure Only, ~ hear stress carried by c o n('~l'ctc 1', sh"n not exceed 0.09
J~
lrnlcss a more dcwiled calculntiun is made in
actordance with Section 424.8.4 .' . 424.8.4.2 Por members subject 10 axial co mpression , shear stress carried by concrete 1/(' J shall no t exceed 0.09
IT:
unless a mo rc de tailed c
424.7 Compression Members With or Without Flexure I', = O.09( I + 0.6N/A,)
424.7.1 Combined flexure and axial load capaci ty of compression membcrs shall be takcn as 40 percent of that computed in accordance with provision s in Sec tion 410 of thi s C hapter. 424.7.2 Sle nderness effects shall be included according to requi rements of Sections 410.10 through 410. 13. In Eq s. 410· I3 and 4 10·22 the term p" shall be re placed by 2.5 times the des ign axial load. and the fa c tor 0.75 shall be taken equal to 1.0.
424.7.3
Wall s s hall be desi gned in accorci:a nce with Section 414 of thi s secti o n with ncxurc a nd axial load capacities ta ken as 40 percent of thaI compu ted using Sectioll4 14. III Eq. 414·1 , ¢ shall be taken eq ual to 1.0.
JT
(424·2)
where N is ncgative for tcn sion . Quantity NIA g shall be expressed in MPa. 424.8.4.4 For members subject to shear and flexure only, it shall be permitted 10 co mpute IIr by l',
but
Vc
= 0.085
If: + 9p".vdIM
simI! not excecd 0. 14
(424·3)
JT .Quanti ty VdlM shall not
be. taken greater than J .0, where M is des ign moment occurri ng simu ltaneously wi th Vat sec ti o n considered. 424.8.4.5 For membcrs subject to axia l compression. it shall be pennilled 10 compu te 1'(' by v, = 0 .09( I + 0 .09N/A,)
If:
(424·4)
424.8 Shear and Torsion Quantity NIA, ,hall be expressed in Mra.
424.8.1
Design shear s tress v shall be compu ted by
" = VI(b.d)
(424· I)
where V is design shear force at section considered .
or
424.8.4.6 Shear stresses carried by concretc 110 apply to norm al weigh t conc rcte. When Iigiliweight aggregate concrete is used, one of th e following modifications !-ildl appl y:
4 24.8.2 When the reaction, in d irect io n app lied shcar. introduces co mpress ion in to the e nd regio ns .11 member, sec tions loc ated less lim n a dis tance d frol11 ftJ<.:e SUppOl1 s ha ll be perm itted to be designed for the sa me shear v as (hat computed at a distance tf.
I.
424.8.3 Whenever applicable , effects of torsion, in accordance with provisions of Section 4! 1 of this section, shall be added. Shear and torsio nal momellt strength s provided by Conc rete and limiting maximum strengths for
2.
or
or
When In is spec ifi ed ,111<1 concre tc is proportioned ill accorda nce wi th Secti o n 405.3, [../6.7 shall be s ubstituted ror exceed When
If:
bu t the va lu e of [../6.7 shall not
\1 f 'r . Ie/
is not s pcci f-,cd, the valu e of !l~~ shaH bt~
multiplied by 0.75 fo r "all~lighlweight" concrete and by 0.85 for "sand~lightweight " co ncrete. Linear
Associ ation of Structu ral Engineers of the Philippines
CHAPT ER 4 .- S tructura l Concrcte
inlc rpo]'ll ion sha ll be pcrm illctJ whcn pania l sand re pl accmc nt is used .
4 · .47
424.8.5.5 Mini mum She;! r Uci nforcc mcnt
or !-ohear re info rce ment Shilli be prov ided jll ali re info rced concrete flex lI f
424.8.4.7
In de tc rmi ning shcar stress carried hy co ncrete
1'(., whenever appli cab le. effects o fa x. i al tensi on duc {O creep and shrinkage in restrained mem bers shall be incl uded and it shall be pcrmillcd to in c lud e e ffec ts or incli ned flexural compressio n ill variabl e-dep th members.
I. 2.
Co nc rete joist cons(rll cti o n defi ned by Sect ion 40g , 14 of this section;
424.8.5 Shea r Stress C;l r ri cd by Shear Ucinfo rcemcnt 3.
424.8.5. 1 Types of Shea r Reinforcement
Slabs and footin gs;
Bea m with total depth Jl o t greater than 250mrn. 2.5 times thic kness of flan ge, 0 [" o n e~ha l f the wid th of we b, whicheve r is gre atest.
Shear re in forceme nt shall consist of o ne o f the fo ll ow ing:
J.
StiITups pcrpe nd ic ul ar
2.
W el ded wi re fa bric with wi res located perpendicular to ax is of mem ber mak ing an anglc of 45 degrees or more wi th longitudin al tensio n reinforcem ent ;
3,
10
ax is of membcr;
Longi tud inal re info rce ment wit h bent portion ma king an ang le of 30 degrees or mo re wilh lo ngitudinal
ten sion rei nfo rce me nt; 4.
5.
424.8.5.5.2 Minimu m shear re inforceme nt req uire ~m e n( s of Sec ti o n 424.8 .5.5. 1 shall be pcnni tled to be waived if shown by test that required ultim ate fl ex ural a nd shear stre ngth ca ll be developed when shear reinfo rceme nt is o milted.
Combinat io ns of sti rrups and bent longitud inal rein forcement ;
A,. = b,sI3(,.
(424· 5)
wh e re bl< ' and s are in 111m .
Spira ls.
424.8.5.2 De sign yie ld strength of shear re info rcement shall no. exceed 41 5 MPa. 424.8.5.3 Stirrups and olher bars or wires used as s hear rein fo rcement sha ll extend Lo a dista nce d from ex treme compression fi ber and shall be anc ho red at both end s accord ing to Secti o n 412. 14 of thi s sec ti o n to develop design yie ld stre ngth of re inforcement .
424.8.5.4 Spacing Limits for Shear Reinfo rcem ent 424.8.5.4.1
424 .8.5.5.3 Where shea r re info rcement is requ ired by Sec tion 424 .8.5.5. I o r by anal ysis , minim um are a of she ar re info rce ment shall be compu ted by:
Spacing
of
shear
reinforcemen.
424.8.5.6 Design of Shea r Reinforcement 424.8.5.6.1 Where design shear stress \' exceeds shear stre ss c arried by co nc rete \/f , shear re inforcemen t shall be prov ided ill accordance wit h Sec tions 424.8 .5.6. 2 thro ugh
424.8.5.6.8. 424.8.5.6.2 W hen s hear re in fo rce me nt perpendic ular to axis of member is used:
A,. = (v - v,)b"s 1[,. placed
perpendicular to a xis of me mber shall no t ex ceed d/2, nor
(424·6)
424.8.5.6.3 When incli ned stirrups are used as shear rei nforccmel1 t;
600 mm .
(v-v , k ." 424.8.5.4.2
Inc lined sti rru ps and be nt lo ngitudin a l re inforcement shall be so spaced lhat eve ry 4 S ~ deg ree line , extending toward the reaction fro m Ill i d~d ep{ h o f me mbe r (d/2) to l o ng itudinal tCrl:-;i on reinforceme nt . shall be crossed by al icasl o ne li lle of shear re in forcemen t.
424.8.5.4.3 When (v-ve) exceeds 1/6 f f , maxi mu m spacing given in See. ions 424.8.5.4.1 and 424.8.5 .4 .2 shall be redu ced by one· half.
A,.
(424·7)
= (,(s in a + cos a)
424.8.5.6.4 Whe n shear re inforcement consis(s o f ;l s ingl e bar or a single group of para lle l bars, all ben t up at the sa me di sta nce from the suppo l1:
A,.
{l'-v,}b•.d
(424 ·8)
(.si n a
where (v · v, ) shall not exceed ( 1/8)
National Struct ural Code of the Philippines 6'" Edition Volum e 1
ff.
4-14{j
CHAPTEJi 4 -~ Str"uCl(Jral Concrete
424.8.5.6.5 When :>hcar reinforcement con:>i:>t:> or a series of paralic! benl-up bars or groups of parallel bent~up bars at differcnt distances from Ihc support, required area shall be computed by Eq, 424-7. 424.8.5.6.6 Only the center three-quarters of the inclined pOI1ion of any longitudinal bellt bar shall be considered effective for shear reinforcement. 424.8.5.6.7 When more th If! ,one type of shear reinforcement is used to reinforce the saille portion of a member, required area shall be computed as the sum of the various types separately. In such computations, v(" shall be included only oncc.
424.8.5.6.8
Value of Iv - v,) shall not exceed (3/8)'[1';.
424.8.6 Shear-Friction Where it is appropriate to consider shear transfer across a given plane, such as an existing or potential crack, an interface between dissimilar materials, or an interface between two concretes cast at different times, shear-friction provisions of Section 411.8 of this Chapter shall be permitted to be applied, with limiting maximum stress for shear taken as 55 percent of that given in Section 41 I .8.5. Permissible stress in shear-friction reinforcement shall be that given in Section 424.4.2. 424.8.7 Special Provisions for Slabs and Footings 424.8.7.1 Shear capacity of slabs and footings in the vicinity of concentrated loads or reactions is governed by the more severe of two conditions; 424.8.7.1.1 Beam action for slab or footing, with a critical section extending in a plane across the entire width and located at a distance d from face of concentrated load or reaction area. For this condition, the slab or footing shall be designed in accordance with Sections 424.8.1 through 424.8.5. 424.8.7.1.2 Two-way action for slab or footing, with a critical section perpendicular to plane of slab and located so that its perimeter is a minimum, but need not approach closer than dl2 to perimeter of concentrated load or reaction area. For this condition, the slab or footing shall be designed in accordance with Sections 424.8.7.2 and 424.8.7.3.
424.8.7.2
Design shear stress v shall be computed by ,.
~
(11(1),,<1)
(424-9)
where V and b" J shall be taken al the critical section defined in Section 424.8.7.1.2. 424.8.7.3 Design shear stress v shall not exceed I',. given by Eq. 424-10 unless shear reinforcement is provided ", =
but
1'("
I( + 7{2)1---
12
I
(424-10)
V!',
shall not exceed (l/6)J7~: f3,- is the ratio of long side
to short side of concentrated load or reaction area. When lightweight aggregate concrete is llsed, the modifications of Section 424.8.4.6 shall apply. 424.8.7.4 If shear reinforcement consisting of bars or wires is provided in accordance with Section 411.13.3 of this section, II,. shall [lO! exceed (1/12) Ir~:, and \' shall not
exceed 0.25 [1;. 424.8.7.5 If shear reinforcement consisting of steel 1- or channel-shaped sections (shcarheads) is provided in accordance with Section 411.13.4 of this section, I' on tlie critical section defined in Section 424.8.7.1.2 shall nut exceed 0.3 and I' on the critical section defined in
rr:,
Section 4 I l. I 3.4.7 shall not exceed (1/6)
ff . In Eqs.
411-
41 and 411-42. design shear force V shall be Illultiplied by 2 and substituted for VII . 428.8 Special Provisions for Other Members For design of deep flexural members, brackets and corbels, and walls, the special provisions of Section 411 of this section shall be used, with shear strengths provided by concrete and limiting maximum strengths for shear taken as 55 percent of the values given in Section 411. In Secfior: 41 J .11.6, the design axial load shall be multiplied by 1 '2 if compression and 2.0 if tension, and substituted for Nw 424.8.9 Composite Concrete Flexural Members For design of composite. concrete flexural mer, permissible horizontal shear stress Vir shall not exccr,rl '/j percent of tbe horizontal shear strengths given in SCi',', ; 417.6.3 of this section.
Association of Structural Engineers of the Philippines
CHA PTE: H 4 - Struct ural Concre te
<1.
1 4 ~,
425.410.4 General Prin ciples and Requirements
425.1 Scope Des ign fo r flexure and axi a l load by provis ions of Section 425 shall be permitted. When Section 425 is used in design. Sec lion , 425.2. 425.2.1 . 425.2.2. "nd 425.2 .3 shall replace the corresponding provisions in Section 408 ; Section 425.410.4 .3 shall replace Seclions 410.4 .3. 41 0.4.4. and 410.4 .5, excepl Section 410.4.5.1 shall remain; Sections 425.418 .2.3. 425.418.9. 1. 425.418.9.2. and 425.418.9.1 shall replace the com!sponding numbered sec tions in Seclion 418; Seclion, 425.418.11.4. 425.418.11.4 . 1. 425.418.11.4 .2. and 4 25.418. 11.4 .3 s hall re place Secli ons 41 8. 11.4 . 418 .11.4.1 .4 18. 11.4.2 and 4 18. 11.4.3. [f any sec lion ill Section 425 is used. all secti ons in Section 425 shall be substituted for the corresponding secti ons in the body of the code, and all other sections in the body of the code s hall be applicable.
425.2 Redistribution of Negative Moments in Continuous Nonprestrcssed Flexural Members For cri teria on momcllI redistri bution for prestressed concrete members, see Sec ti on 425.41 8. 11.4 . 425.2.1 Except where approximarc values for moments are used , it shall be pcnnilted to decre ase factored moments calculated by elastic theory at sections of maximu lll negative or maximum positive moment and in any span of continuous nexu ral members for any assumed load ing arrangemcill by not more than:
20 (I- P;,p')
percent
(425 - 1)
425.410.4.3 For flexural members and members ~ubject to combined flex ure ilnd compressive axial load where ¢P" is less than the smaller of O. IO!c...A . . an d ¢Pb , the rat io or reinfo rcement , P. provided sh all not exceed 0.75 of the ratio PI, that would produce balanced st rain c onditions for the section und er flexure without axi(\1 load. For members with compression rei nforcement. the portion of PI> equali zed by compression reinforceme nt need not be reduced by the 0.75 faclor.
425.418.2 Scope 425.418.2.3 The following pro visions of thi s code shall nol apply to prestressed concrete, except as specifically noted : SccliollS 406.4.4. 407.7.5. 408 . 13.2. 408.13.3, 408 . [3.4 , 408 .13. 410.6. 410.7. 410.10.1. 410. 10.2. and 425.2. 425.4[0.4.3; Seclion 413 ; alld Seclions 4[4 .4 . 414 .6 alld 4 14 .7. 425.418.9 Limits for Reinforcement of Flexural Members 425.418.9.1 Ratio of prestressed and non prestressed reinforcement used for computation of moment strength of a member, e xcept as provided in 425.4 18.9.2, s hall be such Ihal co,. [(oJ, + (dld,)(co - <0' )J. or [<0,•. + (dldp)(
b. 425.2.2 Redistribution of moments shall be made only whcnlhc section at whi ch moment is reduced is so design ed th at fJ or p - p' is not greater th an 0.501'11> w he re:
p, = .0.85
fl, f', (~_) f,. 600 + f ,
425.418.9.2 \\' hen a reinforcemen t rati o exceeds the lim;t specifi ed in Section 425.4 18.9. 1 is provided, de.<;igll moment slre ngt h sha ll not exceed the moment st rength based on the co mpress ion portion of the moment couple.
(425-2)
425.2.3 The redu ced moment sh all be used for calculatiIlg redistributed mom ents at all other sections within the spans. SIalic equilibrium shall be maintained after redistribution of moments al each loading arrangement.
Naliona l Struc lu ra l Code o f the Philippines 6'" Edilion Volume 1
4· I !)O
CIfI\PTEr1 11 _. StruclUfal Concrete
425.418 .9.:\ Tma l allloun! of prestressed and lIonprcstn:ssc::d reinforce mcnt shall be i1dcquatc to deve lop iI fac tored load ilt least 1.2 limes the cracking load computed 1)1} tile basis of the 11IOd uius of rupture!, specil'ied ill Section 409.6.2.3. This provision shall be permitted to he \v.lived for:
1.
425.418.11.4.3 The reduced nwment shall be used for calcui
Two-way, unho nded post -tc nsio ncd slabs; and
2 . . Fl exura l members with shear and n ex ura l st rength at . leas t twice that required by Section 409.3. 425.418_11 Static'llly Indeterminate Structures 425.41 8.11.1 Framcs and continuous co nstruct ion of prestressed concrete shall be des igned for satis f actory pe rfo rm ancc al se rvice load co ndi tions and for adequate strength . 425.418.11.2 Pe rfonnance at service load condit ions shall be dctermi ned by el astic anal ysi s, considering reac ti o ns, mome nt s, shea rs . and axial forces produced by pres tress in g, creep, shrinka ge. tcmperature change, ax ial deform ati on, restraint of attached structural elemcnt s, and foundati o n sc tll clne nt . 425.418.11.3 Moment s to be used to co mpute requ ired strength sha ll be lhe sum of the mome nts due to reac ti o ns induced by prestressi ng (with a load factor o f 1.0) a nd the moment s due to fac tored loads. Adjust ment o f th e sum of these l110menl S sha ll be penn itt cd as all owed in Section 425.418.11.4. 425.41 8. 11.4 Redistribution of Negati ve M om ent s ill Continll olls Pres tressed Flexural M embe r s 425.418.11.4.1 W here bonded rein force ment is provided at supports in accordance wit h Section 418.10, nega tive or posi tive moments calcul ated by elastic theo ry fo r any assu med loadi ng, arrangement shall be perm itt ed to be increased or decreased by not more than: WI'
+ (d Idl')(w - (V')]perccill 0.36/3, (425·3)
425.4J 8. 11.4.2 Redistributio n of moments shall be madc onl y when the section at which moment is reduced is so designed that COp. I'd" + (dld,,)(w - w·).J or Ico,,,,. + (dltlp)«O",(I)',J.I. whichever is a ppl icable, is not greate r th an O.24P •.
Assoc ia tion of S tructural Engine ers of Ole Philippi nes
.
. .:
CHAPTEfl -1 . StfllClllral COllcrelC
1j · 151
426.409.2.5 If resistance_ to iJllpat.'1 cfTct.'ts is taken into 'JCCOli nt in design , slich effects shall be included with L. 426.409.2.6 Where structural cJTc('(s oj' differential settlelllent . creep. shrir)kagc, expansion or sh rinkage compensati ng (;Or1crcle. or temperature <.:hange. T. arl~ signifll.:alll , U shall not be less than the larger of Eqs. 426-5 and 426-6:
426.409.1 Scope Structural concrete shall be pennillcd to be designed lIsing th e load combinations and strength reduction factors of
Section 426. When Section 426 is used in design, Sections 426.409.2. I through 426.9.2.7 shall replace Sections 409.3. I through 409.3.5, and Sections 426.409.3. I through 426.409.3.5 shall replace Section 409.4.1 through 409.4.5.
U=O.75(1.4D+ 1.47'+ I.7L)
(426-:':}
U ; 1.4(1) + 1)
(426-6)
Estimations or differential settlement, creep. shrink
426.409.2 Required Strength 426.409.2.1 Req uired streng th U '0 re,ist dead load D and live 10:ld L shall not be less than: U; I.4D+ 1.7L
426.409.2.7 POf pos t· tensioned ,mchofage zone design. ~ load factor of J.2 shall be applied to the maximuill prestressing stee l jacking force.
(426-
I)
426.409.3 Design Strength
426.409.2.2 For stlUc tures thaI also re sist W, wind load, or
426.409.3.1 Design strength provided by .1 mcmber, its connections to other membcrs, and its cross sections. in terms of nexurc, axial load. shear, and torsion. shall be taken as Ihe nominal strength calculated in accordance with requirements and assumptions of this Code, multiplied by the ¢ [actors ill Secti ons 426.409.3.2, 426.409.3.4. and 426.409.3.5 .
E , the load effects of earthquake. U shall not be less than
the larger of E
U; 0.75(1.4D + J7L) + (J.6W or J.O£) (426-2)
and U=0.9D+(J.6Wor 1.0£)
(426·3)
Where W has not been reduced by a direc tionality factor, it shall be permitted to use I.3W in place of 1.6W in E
426.409.2.3 For stmctures that re sist H, loads due to weight and press ure of soil. water in soil. or other related materials, U shall r,ot be less than the larger of Eqs. 426- I and 426-4: U= I.4D+ 1.7L+ 1.7/-1
426.409.3.2 follows:
Strength reduction f
426.409.3,2.1 Tension-controlled secti ons, as defined III Section 410.4.4 (Sec also Section 426.409.3.2.7) ........ 0.90 426.409.3.2.2 Compression-controlled sections, as defined in Section 410.4.3:
I.
Members with spiral reinforcement conforming to Section 410. 1003 .. 0.75
2.
Other reinforce.d membe rs
0.70
(426-4)
In Eg. 426-4, where D or l. reduce the effect of II, 0.9/J shall be substituted for lAD, clnd z.ero value of L shall be used to determine the greatest required strength U.
426.409.2.4 For struct ures that resist F, load due to weight and pressure of nuids with well-defined densities, the load factor for F shall be lA, and F shall be added to all loadi ng combinat1ons that include L.
For sections in which lhe net tensile strain in the exlre!l1(~ tension steel at nominal strengt h, c" is between the limits for compression-controlled and tension-controlled sections. ¢ shall be pcnnillcd to be linearly in cre~lscd from that for compression·controlled secti ons to 0.90 as 1:1 increases from th e compression co ntrolled strain limit to 0.005.
Alternatively, when Section 425 is used , for members ill which ];. docs ' not exceed 415 MPa. with symmetric reinforcement, and with (d - d')/h not less than 0.70, ¢ shall
National Structural Code of the Philippines 6'h Edition Volume 1
, 4 -1 ~2
C'; HAPT f: Fl 4 •. Structural Concrete
be pcrmiltcd to be increased linearly to 0.90 as (JP" dec reases from O. IOf'.A g to zero. Fo r ot he r reinrorccd members, ¢ shall be permilled 10 be incrca ~c d linearly 10 0.90 as rfJPII decreases from O.JOj;"Ag or rpp". whi che vcr is smaller. to zero. 426.409.3.2.3 Shear and torsion
... .. .. ... . 0.R5
426.409.3.2.4 bearing on concre te (except for posttcnsioned anc horage zones and stnlt-
0.80
426.409.3.2.6 Strut-and-ti e models (Section 427), and slnl!!), lics. nodal zones, and bearing areas in such model s 0.85 426.409.3.2.7 Flexure sections without axial load in pre~ ten sioned mem be rs where strand embedment is less than the development length as provided in Section 412. 10. 1. 1...... ..... .... ...... .. .... ............................ ... 0.85 426.409.3.3 Development lengths specified in Sec tion 41 2 do not require a ¢-factor. 426.409.3.4 For structures lhat rely on intermediate precast structural wall s in region s of high seismi c risk or assigned ( 0 hi gh seismic performance o r design categories (seism ic zone 4), spec ial momenl frames, or special struclU ral wall s to resist E, ¢ sha ll be modified as given in (l) through (3):
i.
2.
For any structural member that is designed to resis t E. ¢ for s hear shall be 0.60 if the nomi nal shear strength of the member is less than th e shear correspondin g to the development of the nominal flexural strength of the member. TIle nominal flexural strength shall be determined cons idering the most critic al factored axial loads and including E; For diaphragms, if> for shear shall not exceed the for shear used for the vertical mi ni mum ¢ component s o f the primary latc ral·forcewresisting
system; 3.
427. 1 Definitions B-REG ION. A port ion or a member in which th e pianC'. sections ass um ption of nexurc Iheo ry from SC(;iion 410. ':. 2 call be applied.
DISCONTINUITY. An abrupt chan ge in geome try nr loading.
D-REG10N. The ponion of a Incm ber withi n
~~~~..:.
Figu re 427 -2(,). 427-2(b), and 427- 3.
NODAL ZONE. The volume or co nc rete ,1I'OllllU ;t ',ode that is assumed to trans fer strut -und-tic forc!.';,. ; 1I1rou;', the node . Hi slOrically. hyd rosl3tic noda l zones ;j ~; s h o ",·r~ ii, Figure 427- 4 werc used . These we re largely S('li, : "'_ ;:, ' "> whal a rc called extended noda l lones, shown in Fi l~.ur(' :12 7·
5. NODE. Th e point in a joinJ. in a strut-and-ti c model wll e re. the axes of the s tnllS. tics, a nd concent rat ed (ll rco :.;.1, :: ,. ! !I the joint intersect. STRUT. A compression member in a slrul ":I!HI-lie IlL'del. A st rut represen ts the resuhalll of a parall el or a fall-shaped compression fi eld. BOTTLE-SHAPED STRUT. A strut th at is wieler at mil' length than a t its cnd s. STRUT-AND-TIE MODEL. A tru ss model nf a struc- 'I;'! member or of a D-region ill such a mClllb, .', \ ;-'i ! de \J, struts a nd ties connected at nodes, cap
ror joints and diagonally reinforced coupli ng bea.ms , ¢ fo r shear shall be 0.85.
426.409.3.5 In Secti on 422, if> shall be 0.65 for n exure, compression, shear, and bearing of st ru ctu ral plain concre te.
Association of Structu ral Engineers of the Philippines
CHI\PTFH 4
427. 1. 1 J)isl'on tinuily
A dis(.·olll illuity ill the stress distribution occurs al a chan ge in the geome try of:l stru ctural clemcnt or at II cO Jl('cntratcd 10
Co ncrete
res ult!i in bearing stresses thin arc equa l 10 the st resses ill the Mruts. The bea rin g phne 011 the left s ide of Figure 4274(h) is used to represe nt an aCIU,d l ie an chorage. The tic force <.:
or st raight or hoo ked hm's, ilS shown in Figure 427·4{c). The shaded areas ill Fi gu re 427 ~ 5(a) lind (b) nrc extend ed nodal zones. A n exte nded nod:11 zolle is thaI porti on o f a member bou nded by lhc inlCJ'seclion of the cffec livc··q rut width , I!I" and th e effective li e widlh, 11', (sec Sec ti on 427.4 .2).
The shaded reg ions in Figu re 427· 1(a)
and (b) show Iypical D-regions. The pl ane sections ass umpti on of Sec ti on 41 0.3.2 is not applicable in such regions.
Each shear span of the beam in Figure 427-2 (a) is it D· as show n in Fi gure 427-2{b), they ca n be considered as a singl e D ~ reg i o n for design purposes. The ma ximum l e n g t h ~ t o -d ep th ratio of sll ch a D-rcgion would be approx.imatcly 2. Th us, the small es t a ngle be tween the strut and the tie in a D-rcgio n is regi on. If two D-region s overlap or meet
arctan V,
.~ S lfllCtl.JF(l!
= 26.5 degrees , rounded to 25 dcgrees .
If there is a B-region between th e D-rcgi o ns in a shear span, as shown in Figure 427-2(c), the st rength of the s hear span is governed by the strength of the B-region if the B- and D· regions have simil ar geomctry and reinforcemcnt. This is because the shear strength of a B-region is less Ihan the shear slrength of a comparable D-region. Shear s pans 427.1.3 Hydros lalic Noda l Zone has loaded faces perpe ndi cu lar to the' axes of the strut s and ties actin g on the node a nd has equa l stresses o n the loaded faces. Fi gure 427 ~ 4(a) shows a C-C-C nodal zone. If th e stresses on the face o f the nodal zone are thc sa me in all threc struts, the ratios of th e lengthS of the sides o f the nodal lone, w~ J: w.2: \II 3 are in the sa me proportions as the three forces C: C,: C). The fa ces o f a hydrostatic nodal zone ~re perpendi c ul ar 10 the axes o f th e struts and lies ac ting on the nodal zo ne. H
These nodal zo nes
A C-C-T nodal zone can be represented as a hyd rostatic nodal zone if the ti e is ass umed to extend through the node 10 be anc hored by a plate on the far s ide of Ihe node. as shown ill Figure 427-4(b), provi ded lh at the si ze of the plate
'h
National Struc tural Code o f Ihe Philippines 6 Edition Volume 1
CHAP I F f ~ t1 - - Str'llcl(Jr~11 Cr)fl(.;r el {~
-'I 1!;ll
h1I(tf=r~--.Gi-)I h2
- D-region
J......I ... -+-t
mm
h1 h2
(t
(a) Shear span, av< 2h, deep beam
i:"':'
h'1
WillWlill (a) Geometric discontinuities
I I
h
1
av =2h , I
1._~_=_2--,L h_ . t Min. of 25 deg "I (b) Shear span, av = 2h, limit for a deep beam
h
1-
D-region
(t{ , - , tDIh I.
[h
I I
2h
D-regio
,I
I'
.Jl
mmlll HI III
CJ t t t (b) Loading and geometric discontinuities
l Ii+-:
_~h_h_ :I
_ h--'-'C a'v_> _2h_ _, 1 - ,_------' av_>
(c) Shear span, av > 2h, slender beam
Fi gu re 427 ·-1 I) -Regions An d Disco nt inu ities FiguI'C 427·2 Descripti on of Deep and Slender Beams
Bottle-shaped strut -
"r Nodal 7.one --Idl>allzed I
I
prismatic strut
/ /
/
/ /
/ Tie ··
Figure 427-3 Description of Slrllt-and-Ti c Model
(8) One layer of slee'
(,sinO
w,
t.~,
see A.4.3.2
(b) Dislribuled sleel
Figure 427·4 Hydrostati c Nodes N. B. : For A.4.1.2, refer to 427.4.3.2
In the nodal zone shown in Figure 427-6 (a), the reac ti on R equilibrates the vertical components of the forces C, and C1.. Frequently, calculations are ea.sier if lhe reaction R is divided into R I , which equilibrates the vertical components of the force C, as shown in Figure 427-6(b).
th
N<~non(ll Structural Code of the Philippines 6 Edition Volume 1
"
tl 1S6
.,.,
,
CHAP fEFl4 .. S!ruCiUfi!1 Concrete
c, c,-....".....,~
(8) Noda/ zone (a) Gooma/ry
c,
(b) Subdivid8(i l1c>C/"r .OJ, Figure 427-6 Subdivisioll of Noda l Zone (b) Tension force anchor(J(} by 8 plate
C
C \ \
\ \
t.m::. see AA .3.2 I
I
I
I
I
I,~-----c
I I I
:C
(a) C-C-C Node
~ Critical soction for f
I
~T
C
.
I
I
T
(b) C-C- T Node
T
development f)( tie reinforcemenl
c (c) Tension force anchored by bond
Pignrc 427·5 EXlcndcd Nodal Zone Showing the Effect of the Distributi on of th e Force N. 13 . : For A.4.3.2, refcr to Scction 427.4 .3.2
T (e) C- T- T Node
(d) T- T-T N(,,:,!
Fi gure 427 -7 Classificat ion of Nudes
Association of Structural Engineers of the Philippines
427.1.4 Nodes
/ Crack
For equilibrium, at lcasllhrcc forces should act on a node in
a strut-and-lic model, as shown jn Figure 427-.7. Nodes
classiticd according to the signs of these forces. A C-C-C
/
node resists three compressive forces, a C-C- T node resists
(wo compressive forces and one tensile force, and so on.
· Tie
""-~:f
afC
~~ed
" ,":>-' .'
~---
/~-
Strut
2
/ to compute Ao
(8)
(b)
427.1.5 Strut
In design, struts arc usually idealized as prismatic
Figure
compression members, as shown by the straight line outlines of the struts in Figures 427-2 and 427-3. If the
427~8
Bottle-shaped Strut: (a) Cracking of a Bottle-shaped Strut; and (b) Strut-andTie Model of a Bottle-shaped Strut
effective compression strength};", differs at the two ends of a strut, due either to different nodal zone strengths at the two ends, or to different bearing lengths, the strut is idealized as a uniformly tapered compression member.
Bottle-shaped struts - A bottle-shaped strut is a strut located in a part of a member where the width of the compressed concrete at mid length of the strut can spread laterally. The curved dashed outlines of the struts in Figure 427-3 and the curved solid outlines in Figure 427-8 approximate the boundaries of bottle-shaped struts. A split cylinder test is an example of a bottle-shaped strut. The internal lateral spread of the applied compression force in such a test leads to a transverse tension that splits the specimen. To simplify design, bottle-shaped struts are idealized either as prismatic or as uniformly tapered, and crack-control reinforcement from Section 427.3.3 is provided to resist the transverse tension. The amount of confining transverse reinforcement can be computed using the strut-and-tie model shown in Figure 427-8(b) with the struts that represent the spread of the compression force acting at a slope of 1:2 to the axis 'of the applied compressive force. Altematively for to' not exceeding 40 MPa, Eq. 427-4 can be used. The cross-sectional area At of a bottle-shaped strut is taken as the smaller of the cross-sectional areas at the two ends of the strut. Sec Figure 427-8(a).
427.2 Strut-andTie Model Design Procedure 427.2.1 It shall be permitted to design stI1Jctural concrete members or D-regions in such members, by modeling the member or region as an idealized truss. The truss model shall contain struts, ties, and nodes as defined in Section 427.1. The truss model shall be capable of transfen'ing all factored loads to the supports or adjacent B-rcgions. 427.2.2 The strut-and-tic model shall be in equilibriulll with the applied loads and the reactions. 427.2.3 In determining the geometry of the truss, the dimensions of the struts, ties, and nodal zones shall be taken into accounl. 427.2.4 Ties shall be permitted to cross struts. Struts shaH cross or overlap only at nodes.
e,
between the axes of any strut and any 427.2.5 The ang1e, tie entering a single node shall not be taken as less than 25 degrees. 427.2.6 Design of struts, ties, and nodal zones shall be based on: (427-1) where Fu is the factored force acting in a strut, in a tic, or on one face of a nodal zone; 1~1 is the nominal strength of the strut, tic, or nodal zone; and ¢ is specified in Section 409.3.2.6.
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National Structural Code of the Philippines 6 Edition Volume 1
427.3
S(J'c l1 ~th (If
(427·4)
Struts
427.3.1 The l1 omin ;d comp ressive strength of' ;1 str ul '\lilhoHI h)lI gilUdinal n:i nfon..:elllcllI. r~", sh;dl be wkcll as the smallcr value of: r~,\
=./;,A"
(427·2)
al th e IwO end ... of II}!! stru t, where 11(1 is thL ..:.oss-stttion:tI al Ol h! end of Iht' sI nH. and /.1' is the slllilJ lrr ()f ( I)
ilrca
(2):
I.
2.
The clTcctivc compressive strenglh of the conc rete in the SInH given in Secti on 427.3.2;
The effecti ve compressive strenglh of th (.'. concrete ill the nodal 7.0nc given in Scc iion 427.5.2.
427.3,2 T he effecti ve comprcssi ve concrete, };.,. in a strut shall be taken as :
strength
of
/.e = (J.XS/IJ.'
the
(427· ) 1
427.3.2.1 For a stlllt of un iform cr()ss~seclion a! area over ils lel1glh ... ... .. ............. /1, = 1.0 427 .3.2.2 For stmls located such thai Ihe width or the midsecti on of the sinH is large r than th e widt h (II Ihe nodes (bottle·shaped slnns):
J.
Wit h reinforce ment sati sfy ing Sec ti on 42 7.3.3 . p, =0 .75
2.
WithOl1t 427.3.3 ...
reinforcement
sati sfying
................ If,
Section = O.6(J!'
where the VIII lie of I.. is defined i n Secti on 408.7.1. 427.3.2.3 For struts in tension members, or the tension Oanges of members .... ......... .. /1, = OAO 427.3.2.4 For all other ease s
p, = O.60i.
427.3.3 Ir the value or p, speciried ill Section 427 .3.2 .2( I) is used. the axis of the st rlll shall be crossed by reinforccmcllI propoJlioncd to resist Ihe tran sverse ten sile force res ulling fro m the compression force spreading ill the SInH . It Sh'll! he permitted to assume the co mpressive force in the strut spreads
wil en! A" is th e tollil ,Ire;! of sli rfaL' c r~inrorc cmelll al spaci ng x, in the Hh In.:e mcn! requ ired in Sect ion 427.3 .3 shall be placed in ei ther two orthogona l directi ons at ang les (.(, and 11.1 10 the axis uf the st rut. or in one dircction at an angk (I. !O the axis or the strut. If the reinforccment is in only one directi on, 0. sha ll not be less thall 40 dcgrees. 427.3.4 If docllmentcd hy tests ,tnt! atwlyses, il shall be permitled 10 lise an increased effective compressive strength of a strut due to confining reinfo rcement.
427 .3.5 The usc of compression reinforcement shall be pe rm itted {O increase Ihe si rength of it SinH . Comp ression reinforcement shan be properl y anc hored, parallel to the axis of the SU·III . located wit hin the stru t. and encl osed in tics or sp irah salisfying Section 407. 11. In such cases, the Homin,,1 stre nglh ('I f il longi tudinall y re in forced strut is:
1':,., =};,A ,., + A:);' 427.4 Strength or ·ncs
427.4.1 The nom inal strengt h of a tic. F,,,, shall bc taken as: (427-6)
where (f..,. + 1:-:../;'; shall not exceed nonprcst resscd members .
;;I.\"
and A,l' is zero for
In Eq. 427-6, it shall be pCllnillcd to (ake (~hl equal (04 15 MPa for bonded prestressed reinforc ement, or 70 MPa for ullbonded prestressed reinforcement. Otller values of (51;, shall be permitted whcn justified by analysis.
427.4.2 Th e axis of th e reinforcement ill II tie shall coincide with the axis of the ti e in Ihe stl1l t·and-tic model. The effec ti ve tie width assumed in design WI can vary betw{'('11 the following limi ls. depending on the di stribution of the ( i(; reinrorcement. I.
If the hars in the tic-
2.
A practical uppcr limil of thc tic width cn n be Ifll:(1\ ::s thc wid th cO ITcspomlin g to the width ill a h ydro~t:'hC nod al zone, calc ulat ed as :
axis of the strut. 427.].3.1 For // 110t greater Ihal1 40 MPa, th e requirement of Sectio n 427.3.3 shall be pcrmiHed to be satisfi ed by the axi s of lhe sInH being crossed by layers of reinforcement th at satisfy Eq . 427-4:
(427·5)
"" _. =1-:, {(f..b.)
Association of Structural Engineers of tile PI)ilippines
(427·7)
.. .
where I. IS computed for the nodal zone in accordance with Section 427.5.2. If the tic width excccds tlw v,due from (a), the tic reinforcement should be distributed approximately uniformly over the width and thickness of the lie, as shown in Figure 427-5(b). 427.4.3 Tic reinforcement shall be anchored by mechanical devices, post··tensioning anchorage devices. standard hooks. or straight bar devclopment as required by Sections
where the value or IJ" is given in Seclions 427.5.2.1 through 427.5.2.3.
427.5.2.1 In nodal I.ones bounded by struts or bearing areas, or bOlh . ji" ~ J.(): 427.5.2.2 In lie ..
Jlodal
zoncs
anchoring /1"
011('
~
0.80;
427.4.3.1 through 427.4.3.4.
or
427.4.3.1 Nodal lones shall develop thc difference between the tic force on olle side of the node and the tic force 011 the other side.
427.5.2.3 In nodal zones anchoring two or more lics /i" ~ 0.611.
427.4.3.2 At nodal zones anchoring one lie. the tic force shall be developed at the point where the centroid of the reinforcement in a tic leaves the extended nodal zone and enters the span.
427.5.3 In a three-dimensional strut-and-tie model, the area of each face of" a nodal zone shall not be less than thaI given in Section 427.5. I. and the shape of each face of the nodal zones shaJ! be similar to the shape of the projection of the end of the struts onl0 the corresponding faces of the nodal
zones.
427.4.3.3 At nodal zones anchoring two or more tics, the lie force in each direction shall be developed at the point wher~ the centroid of the reinforcement in the lie !eaves the extended nodal lone. 427.4.3.4 The transverse reinforcement required by Section 427.3.3 shall be anchored in accordance with Section 412.14. 427.5 Strength of Nodal Zones 427.5.1 The nominal compression strength of a nodal zone, f~"" shall be: (427-8)
where Itt is the effective compressive strength of the concrete in the nodal zone as given in Sect. 427.5.2, and An;; is the smaller of (I) and (2): 1.
The area of the face of the nodal zone on which Fu acts, taken perpendicular to the line of action of Fu;
2.
The area of a section through the nodal taken perpendicular to the resultant force on the section.
zone, line of action of the
427.5.2 Unless confining reinforcement is provided within the nodal zone and its effect is supported by tests and analysis, the calculated effective compressive stress, fee. on a face of a nodal zone due to the strut-and-tie forces shall not exceeclthe value given by:
ic, ~ 0.85/3,".'
(427-9)
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National Structural Code of the Philippines 6 Edition Volume 1
NSCP C101-10
Chapter 5 STRUCTURAL STEEL NATIONAL STRUCTURAL CODE OF THE PHILIPPINES VOLUME I BUILDINGS, TOWERS AND OTHER VERTICAL STRUCTURES SIXTH EDITION
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Nalional Structural Code of the Philippines 6 Edition Volume 1
CH AP TEl1 5 " Steel an d Metals
5· '
Table of Contents CHAPTER 5 • STEEL ANI) METALS SPECIFICATION FOR STRUCTURAL STEEL BUILDINGS ..................... II PAIr!' I • SPECIFICATION FOR ST EE L MEMBEHS ...................... ............ ..... ............................... ............................... 11 SyMBOLS ..... ................................................. .............................. ........ ................................. ................... ... ................. ............ II DEFINITIONS ...... ............................................... ........................................... .. ............ ....... .................................................... 18 SECTION 501 . GENERAL PROVISIONS .. ..... ............... ......... ...... ........... .... ...................................................................... 28 501. 1 Scope ... ..
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50 1.2 Referenced Specifications. Codes and Standards ......
501 .3 Matena!. ... ................ ...
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... ....... ......... .. .... .. ...... ....... 28
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50 1.4 Structu ra l Design Drawings and Speci fi catiolls.... ..
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. ...... 32
SECTION 502· DESIGN REQUiR EMENTS .................. ........................................... ......................................................... 32 502.! Gcneral Pro visions .. 502.2 LoaJs and LoHd Combi llal ions ..... . 502.3 Design B'ISis, ............ " .... ...... ........ . 502.4 Classification of Sections for Local Buck li ng .............................................. . 502.4. Un sriffencd Elements ......... .. ..... . 502.5 FabJi c.: ation , Erection and Quality Co ntrol .. 502.6 Evaluation of Ex istin g Stnlctures.
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.... 33 .. ..... 33 .......... 35 ..35 ........... .... ....
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SECTION 503 ... ................................. ................. .............................................................................................................. ....... 39 STABILITY ANALYSIS AND DESI GN .... ................... .............................. ..................................... .................. .................. 39 503. J Stability Design Requirc l11cllls ... 503.2 Cal c ulation of Required Strength s...
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...39 . ... .... .....
. ...... 40
SECTION 504 . DESIGN OF MEMBERS FOR TENSION ..................................................................................... .......... 42 ....... 43 .. ... 43 .. .. 43 ... ... . 44
504 . J Sle nderness Limi tations ...... .. . 504.2 Tensilc Strength .... ............... . 504.3 Area DClermin:uion ...... .... .... .
504.4 Bui(( ·up Members ..... .. .......... ... .. 504.5 Pin -Co nnected Membe rs ... ....... ....... ...... ...... " .. 504.6 Eyebars ..... .. ...... .
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...... 46
SECTION 505 - DESIGN OF MEMBERS FOR COMPRESSJON ........................ ...................... ...................................... 46 ................... 46 505.1 General Provisions ................ ............................ . 505.2 Slenderness Limit.llion s a nd Effective Le ngth .......... . ,, ' ......... .46 505.3 Compress ive Strcngth for Flexural Buckling of Members With out Slende r Elcmc lH s . .... . .. ... ......... .... . .. .. 47 505 .4 Compress i ve: S trength for Torsio na l and Fl ex ural-Tors ional Buck l ing of Members without Sle nder Ele ment s, ........ ... 47 505.5 Single Angle Co mpression Membe rs ............ ,..... ....... 48 505.6 Bu ilt- up Mc mber,
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505.7 Membe rs with Slender Elements
.. ......... 49 .. .... 50
SECTION 506 ·DES IGN OF MEMB ERS FOR FLEXURE .............. .......... ........................... ............................................ 52
506. 1 Gen eral Provisions ..... ........ ..... ....... ......... 506.2 Dou bly SY lllm e tri c Com pac t I-Shaped Me mb ers and Channel s Bent abou t their Major Axi s.....
..... 53
. ..... 55 506.3 Doubly Symmc lric I-S haped Members with Com pac t \Vebs and Noncompacl or Sle nder Fl a nges Ben l about their
Major Axis ............................ ...... ... ......... .......................................................................................... ..... .............. .. ...... 56 506.4 Other I-Shaped Members w ith Compact or Noncompac\ Webs Bent about their Major Axis ,........... .... ,..... .................. 56
506.5 Doubl y Symmetric and Singly Symmetric I·Shaped Members with Slender Webs Bcnt about their Major AxiL ........ 58
National Structural Code of tile Philippines 6
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Edition Volume 1
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C HAP T!: H 5 . Steel and Meta ls
506.6 1·Shapcd Mcmbr.:rs and Ciwllnl!is Gent abo ut their Minor Axi s 506.7 Square illH.1 Rct:liUlgu!ar HSS and Box-sh,lpcd Members ........ . 506.8 Rou nd IISS ............. .. .... ......... .. .......... .. 506.9 Tees and Dou ble A ngles Lo,lded ill the Plane of Symmetry ................ . 506.10 S ingl e Angles................. ................ .. ..................... .. 506.11 Rcclangular Bars and Rounds .. ... ........... .... .... ........ . ........... . 506.1 2 Unsymmetrical Shapes ....... ................... ................ . 506.13 Prop~r! ions of Beams and Girders.... . .......... ....... . .. . ...... ... .... . ......... ....... . .
..................... .')~ .. .. 59 ··· ··· ··· ..... 6u
.. ..... 60 61 . ..... ... 62 ..... ·........ ·...... ...... ·... 63 .. ........... ...... 63
SECTION 507 • DESIGN OF MEMBERS FOR SHEAR ................................................................................................ 65 507.1 General Prov isions... . ............ . 507.2 Mcmber!'> with Unstiffened or Stiffe ncd Webs .. 507.3 Tension field A clion .. ...................... ............ ... .. ..... ....... ..................... 507.4 Single Angles ................................ .. .......... .. 507.5 Rectangula r HSS and Box Members .............. .. 507 .6 Round HSS .......................... .... .. ................. .. 507.7 Weak Axis Shear in Singly and Do ubly Symmetric Shapes .................................................................. . 507 .8 Beams and Girders with Web Openings ................ ......................... ...................................... .
·· ··· .... .. .. 6)
.. .... .. 65 ..... ........ 66 . . ... .. ..... C'}
.. ..... 67 .. 67 .... 67 .. ... 67
SECTION 508 . DESIGN OF MEMBERS FOR COM IlINED FORCES AND TORSION ............................................ 68 508. 1 Do ubly and Singly Symmetric Members Subject to Flex ure a nd Axial Force ... ... ........ ............. ....................... .. 508.2 Unsymlllctric and other Me mbcr$ Subject to Fl exure Ilnd Axial force ..... .. .... ........ ... ......................... . 508.1 Members under Torsion
SECTION 509· DESIGN OF COMPOSITE MEMBE RS ................................................................................. .. . 509.1 General Provisions ........ ............. . 50~.2 Axial Members .... 509.3 Flexural Members ..................... . 503.3 Flexurlll Strength of Concrete -Enc ased and Filled Members.. 509.4 Combined Axi a l Force and Flexure.................. ............... ... ............... .. ................ 509.5 Special Cases ......................................................... .....................................................................................
68 .. .69 .. .70 . ..... 71
. .. ...... 72 . .. 7:' .... ' ., . .. .._...... 7g . ..... 79 ..... 79
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SECTION 510· DESIGN OF CONNECTIONS ................................................................................................ ...... ....... .. .. 79 510.1 General Provis io ns 510.2 Welds.. .......... .. ............ . 510.3 Bolls and Threaded Pans ... .......................................... . 510.4 A ffected El e ments of Members and Connecting Elements .... ............ . 510.5 Fill ers.. ............... .. ............ ........ .. ................. . 510.6 Splices.. .. .. ... .. .. ......... ........................ ........... ..... . 510.7 Bearing Sirength ................... .. .......... ........... ................ .. 510.8 Column Bases and Bearing o n Concrete .... . 510.9 Anchor Rods and Embedments ...... .............. .. . SID.IO Flanges and Webs with COllcentrated Forces ........ ...... ....... ... ... .......... .
... 79 ... 81 ..87 . ..... ....... _.. .. 92 .... 9:\
........ .. 93 .91 .. 0,'~ . ... i)/t . ... ... 1) . ;
SECTION 511 . DESIGN OF HSS AND BOX MEMBER CONNECTIONS ............................................ . 51 1.1 Concentrated Forces on HSS .. 5 11 .2 HSS·to· HSS Truss Connection s ...... .. 5 11 .1 HSS· to·HSS Mo ment Connecli ons .. .
. .. 10"
.. 106
SECTION 512· DESIGN FOR SERVICEABILITY ................................................................ ..... .............. .... .................. 110 512.1 General Provis io ns .............................. . 512.2 Camber ........... .. .................................................................................................................. .. 512.3 Defiections ................................................................ .................. ........................................ .................. . .. 512.4 Drift ............................................................................................ ............................................................... . 512.5 Vibration ......................... .................... ......................... .... .......................... ... 512.6 Wind·Induced Motion ........................... .. .............. .......................... ........... ........................ .
Association of Siructural Engineers of IIle Philippines
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512 .7 EXP;IIISioll allJ Culltra<.:tiull ................ " ...... " ......................................... ............................. ....................................... . 110 5 12 .8 CU fl IlC<:t IOJ1 Slip .................. .................. ...... .................................................................................................. ____ 110 SECTION 513 - FAURI CATION, ERECTION ANI) QUALITY CONTROL_ ............................................. ............... .. 110
5 13. 1 Shop ;lIld Ef'c(.·lion I)l'il\vings ............................ ........................................... ................................................................ 5 13.2 pahril·illioll ... ...................................................... .......................... .. ...................................................... 513 .3 Shop Paillling..... . ........................................................... ................................................ ..... 5 J 3.4 Erectioll ....... .................... ................................ ................. """ ... ,, ... 513.5 Qualil v Conlrol .... .... ........................................... .............. . . ................................ .......................
II J 111 112 112 113
APP E NDIX A-I - INELASTIC ANALYSIS AND DESIGN ....................... _.................................................................... , 114 A· I . J Gc ne,...1 Provisions .......... " ............................. .................................................. ........ ..................................................... ) 14 A-I .2 Mal erial s ................ ................................................. , ............... ,.. ,........................................ ........... ,........... ,.. ,................ 114 A· ] .3 M0111cnt Rcdi stlibuli on ................................................................................................. ................................................ J 14 A-I,4 Local Buckling .................. ......................................................................................................................................... 114 A- 1.5 SI.bilily .nd Second-Order EffeCIS .............................................. .. .............. ................................................ 115 A- I .Sa Braced Frames ............ ............................................................................. ...... . ........ .... ... ........................................ . 115 A ~ J .5b M OlllCll 1 Fr;ullcs .................... . "................................................... ............ ................................. .............................. J 15 A- I.6 Columns and Olher Compression Mcm bers....... ................ .............. ." ................................................. J 15 A· I .7 Beams and Ollicr Flexural Mcmbers.. . .................. ........ ...... .. ..................................................... 11 5 .. ............................................ 11 5 A- I.S Members under Co mbi ned Forces ....................... ........ ... .... . A-I .9 CO rlnecli olls .. "5
APPENDIX A-2 - DESIGN FOR PONDING ......... ""." """""" .. " .......... """"""""""" .. "",,.,, ... ,,.,,""""""""""." .. " .. "" .. 116 J\ ~2 .J Simplifi ed Design for Ponding A-2.2 Improved Design for Ponding
.... . 116 116
APPENDIX A-3 - DESIGN FOR FATIGUE """"""""""""", .. """"""""""""" .. ,, ....... ,,""""""""""" " ,,"""""""", .. ,,'" 117 A-3. 1 Ge ner;d .,', ........ ,......... ........ .................. ,.......................................................................... ,.................................. A·3.2 Calculation of Maximulll St resses and Siress Ranges ........................................................... ....................................... A-3 .3 Design Siress Range .......... ....................................................................................... " ..................................... ....... A-3,4 BoilS and Threaded P.rts ...... .. ....................... " ........................................................................................................ .. .. A-3.5 Special Fabrication and Erection Req uirements .............. ... ............ ................................................................. " ..........
11 7 I J8 118 119 119
APPENDIX A-4 - STRUCTURAL DESI GN FO R FIRE CONDITlONS" ....... "."""" .. ..... ."" .. " .. "."".""",, ...... ,, .......... Il9 A-4.1 General Pro vi sions ... ........................................... ................................. ................ ..................... ................ .. ,........... ...... 120 A-4 .2 Structural Design for Fire Conditions by Ana lysis ......... .. ................................................ .. ................... ...... .............. .... 136 A-4 .3 Design by Qn.lificalion Tesling ................................................ ,.. ,............ ..................... .................................... ,.......... 138 APPENDIX A-5 - EVALUA TlON OF EXISTIN G STRU CTURES .. ,_"""." .. """"", .. "".""" .. "."""""" """,,.,, ........ ,,",139
A·S. I Ge neral Provisions ............ ......... .. ................................................... .. ................... ...................... .... ............................. 139 A-5.2 A-5.3 A-5,4 A-55
Material Pro pel1i es ............................. ........... ...... .. _............................. .................................. .............. .. ...................... E valumion by Slmclural Anal ysis ......... ................. _......................... .. .................... .............. ,........................................ Evalllalio n by Load Tests ....................................... _............................... .............. .. ,... ,............... .. ................................. Evalualio n Reporl ." ............... .... ............................ _........ ....... " .............. ... ............................................ ,......................
139 140 140 140
APPENDIX A-6 - STAB ILITY BRA CING FO J( CO L UMNS AND BEA MS ........ " " " """" ... " ...... """""""",, .. ,, ......,," 140 A·6. J General Pro visio ns .. A-6.2 Columns ................... .. A-6.3 Bea ms ........ .. ............. ..
............................. ............................ .......... .... ..................... ,..................... ,............ 141 .. ............... .. ............................................ .. ........................... ...... 141 .. .................................................................................................................................... 141
APPENDIX A- 7 • DIRECT ANALYSIS M ETHOD "' _" " """""""".""""."."" .... _" ... ""." .... """".",, ..... ,,"",, ......... ""'"'' 143 A·7. 1 Gener.1 RequirelllenlS .............................. . ,........... _....... ,......... ,........................................... ...................... ........ " ........ 143 A-7.2 Notion.1 Loads ... . .. ......................................... ....... "..... .... .. ......... " .............. .. ..... " ................. 143 .......... ... ........... ... ........ ..... ............ 143 A-7.3 Design -A nalysis Constraints .... PART 2A • SEJSMIC PROVISION FOR STRUCTUHAL STEEL BUILDINGS ,,'''''''''''''''''''''''''''',,'''''''''' ,,"" " " " ,," 145 th
National Structural Code of the PI1ilippines 6 Edition Volume 1
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CHAPTER 5 . Steel and Metals
SyMBOLS ....... ................... ................... ........... .. ................ ... ........ ... ................................. ........................ ............. ................ 145 DEFINITIONS ..... ... ................................ .............. ........................ ............................... ................ .... .. .. ..... ............................. 147 PART 2A . SECTION 514 STRUCTURAL STEEL BUILDING PROVISIONS ...... ............................ ......................... 150
. ............ ................ ... .... ISO
514 . Scope .. ... ......... ................................. ................................. .
SECTION 515· REFERENCED SPEC IFI CATIONS, COnES, AND STANDARDS .......·...···... ··.·............··.·.··... ·....... 151 SECTION 516· GENERA L SEISMIC n ES IGN REQUIREMENTS .............. .... ..... ............. ... ............................ ....... .... 151 SECTI(h 517· LOADS, LOAD COM B I NATIONS, AND NOMINAL STRENGTHS .................. ··.. ·.. ·.· ... · ............... 15i 517. 1 Loads and LO
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..... 152 .. . .. .......... .. 152
SECTION 518· STRUCTURAL DESIGN DRA WINGS AND SPECIFICATIONS, SHOP DHAWINGS, AND ERECTION DRA WiNGS .............. ............................................ ..................... ............. ................. .......................... .............. 152
5 18. 1 Structural Design Drawings Hnd Spccifictltimls .......... _.. .......................... . 5 18.2 Shop Drawings .......................... .................................................................... 5 I 8.3 Ercction Dra\vings ....... ............ . ...... ........ ....... ............ ...... .. ........ .. ................. , .. .
152 ..... 152 ............. ......... 153
SECTION 519· MATERIALS .................. ....... ........... .......................................... ............................................................. .. 153
. ........ 153 ...... 153 . .. .. 154
5 19 . 1 Material Specifications ....... .,...... ................. . ............ ................... . 5 19.2 Material Propcni cs for Delcnn inalion of Rcqui red Strength of Mcmbers and Co nnect ions, ..... .. 519.3 Heavy Section CVN Requireme nts. ..... ... .... ...... . ... .. .... ... .... ,., .. .
SECTION 520· CO NNECTIONS , JOINTS, AND FASTENERS .................................................................................... 155
520.1. Scope ... ............... ... 520.2 Bol ted Join ts .......... .................... . 5203 Welded Joint s ............................ . 520.4 PrOleeled Zone. 520.5 Continuity Pl ates and Stiffeners
........ .............
.... 155 ............. 155 .... ....... 155 .................... .. .. ......... .......... 158 .................. 158
SECTION 521 . MEMBERS ........ ..... ............... ........................................................ ............................................................ 159
.......................... 159 .. 159 . . . ••. ....... 159 159 .. IGO . 160
52 1. 1 Scope ........ ............. .. .... .. ... ............ ... ........ . 52 1.2 Classification or Sections for Loca l Bucklin g ....
52 1.3 Column Stren gth ... .... .... ...... ........ ..... ..... ..... .. 52 1.4 Column Splices ...... ...... .... . 52 1.5 Column Bases .. ................ ... . 521 .6 H·Piles ..... .
SECTION 522· SP EC IAL MOM ENT FRAMES (SMF) ..................................... ...................... ....................................... 161
522.1 Scope ............ ........... .. .. ....... ............ ................. ........... ... ...... ..•..•... .............. .............. ................ 522.2 Beam-Io-Columll Connections ,.................................... ...... , ....... , 522.3 Panel Zone of Bcam-to-Colulllll Connecti ons (Beam Web PClrallcl lo Col umn \Veh) ............ .............. 522.4 Beam and Column Limi tati o ns . .............................
.')22 .5 Continuit y Plat es .............. ............. ,. .... . ............ ... 522 .6 Column- Beam Mome nt Ratio. ........ .... .. .. .......... ... ...... ... .. ................. 522 .7 La teral Bracing at Beam -In-Column Connections ..... ...... ... ........ ... ... .... ...... . 522 .8 Lateral Bnlci ng of Beams .. ......... ..... 522.9 Column Splices .... ............ ... .
............. 161 .. 161 . ..... 167.
.... .... ...... . ..... .... .. ...........
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..164
SECTION 523· I NTERMEI))A TE MOMENT FRA~-IlCS (IMF) .. .......................... ............................. .... ....................... ](.4
523 .1 Scope ..... ........ ....................... ........ . .. ...... .. .. ...
........................ ......... ............
............ .. .. .... ........... .......... .• . ' "
523 .2 Beanl-to-Coiunlll Co nnect ions ...... ........... ,... , .... ........ , ........ , ....... ............... , .... .... ........... , ... , .. , ..................... , ....... " , 523.3 Panel Zone of Beam-la-Column Connections (Beam Web Parallel to Column Web) ............ ............................ ....... .. . .J 523.4 Beam and Column Limitations. ............ .... ............... .. ........... ............. .... ... .. .... ,.. ..................... ,(,5
523 .5 Contin ui ty Plates.. ...... ..
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.. ................... .. .... .... .
Associa tion of Structural Engin eers of the Philippines
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CHAPT Eri fi . Sleet and Melals
523 .6 Col umn -Beam MOnlclll Rat io ....... .. .............. .
5
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.................... ............ 165
SECTION 524 . ORDINARY MOMENT FRAMES (OM F) ....................... ............. ... ............. .......................... ....... ,....... 166 524.1 Scope . ....... .......... .. .... .... ....... ... ..... ........... ..... ...... .......... ............... . ......................... .... 166 524.2 Beam·lu·Col umn ........... ...................... .................... .................. .............. .. ................. 166 524.3 Pimcl Zone of BcanH o-Column Con necti ons (Beam Web Paralle l To Colu mn Web) ... 167 524.4 Beam and Col umll Limitations........ ....... ........ ........ ....... ......... ......... .. .. .. 168 524.5 Conlinuily I'lllle5.. ..... . ... ............. ...... .... ........ ... ............... .168 524.6 Columll-Beam Moment Ratio......... ............... ................. . loS 524.7 Lateral Bracing al Beam-Io-Column Connections .................................................... .. ........................... " ... ........... 168 524.8 Laleral Bracing of Bea ms ............. .. .......... ........................... .. ............................................................... 168 524.9 Col umn Splices.. ......... ........................................... ........... ............ .... .................. .. ......... ..................... .... 168 SECTION 525· SPECIAL TRUSS MOMENT FRAMES (STMF) ......................... ........................... .............................. 169 525.1 Scope ............... . 525.2 Special Segmenl .... ........... . 525.3 Slrenglh of Special Segmenl Members .... ..... .. 525.4 Sirengih of Non·Special Segmenl rs....................... .. ............. . 525.5 Widlh·Thickness Limilalions .......................................... ................... ........... . 525.6 Laleral Bracing ........................................... ...... ..
... . 169 .... ... 169 .. 169 .. ........ 169 .. ............................................... 169 .. ......................... 170
SECTION 526 · SPECIAL CONCENTRICALLY BRACED FRAMES (SCBF) ....................................... .................... 170 526.1 Scope ..... ........ ...... ... .......... .... ........ ............... . . .......... 170 526.2 Members ............ .. ....... .......... ...... ............. ....... .. ............ ... .. .. 170 526.3 Required Slrenglh of Bracing Conneelions .. .. .. 17 1 ................ .. 17 1 526.4 Special Bracing Configuration Requiremenls ......................... .............. ................... .................... 526.5 Column Splices ........................................................... ........... ....... .................................... ........................................... 172 526.6 Protected Zone ..... ... ......................... .. .... .. ... ......... ............... ............... .. ..... ........ ... ...... .. ... ............................................ .. 172 SECTION 527· ORDINARY CONCENTRI CALLY BRACED FRAMES (OCBF) ...................................................... I72 527.1 Scope.. ..................... ............................. .............................. .. ...... ........ ................................................ 172 527 .2 Bracing Members ........ ..... .. . .. ................ . ........ ...... ..... ........ .... ... 172 527.3 Special Bracing Configuralion..... .......................... .... ............... .. ..... ...... ...... .. ... 172 527.4 Bracing Conneelion'...... .... ............... ........................ ............... ........... .. .... ............... .. ..... 173 527.5 OCBF above Seismic Isolation SySiems..................................................................................................................... 173 SECTION 528· ECCENTRICALLY BRACED FRAMES (EBF) ................................................................................... 173 528.1 Scope ... ............................... ................. ............................................................................................... ........................... 173 528.2 Links ......................................................................... .. .............. ..... ........................... .. ..................... .. ........................... 173 528.3 Link Stiffeners .......... ....... ....................... ............. ....... .. ............................................... 174 528.4 Lin k·l o·Column Connections ............................................... .......... .. ......... ..... ............... .... ............ 174 528.5 Lateral Bracing of Link ... ........................... .......... ......................... .. .... .... ............. ............ ...... ....... .......... ........... 175 528.6 Diagonal Brace and Beam Outside of Link .............................................................................. ....... ............................. 175 528.7 Beam·to·Column Connections ......... ... ..................... ..... ................................................................................................ 175 528.8 Required Slrenglh of Col umns .................................. ... ................................................... .................................. ...... 176 528.9 Protected ZOlle .......................... .. ............ ........ ............................ ......... ..... ............ .. .................. ..... ................................ 176 528.10 Demand Critical Welds................. ............................................ .. ...... .. ............................................. .. .............. 176 SECTION 529 ·IlUCKLING·RESTRAINED IlRACED FRAMES (IlRIlF) .................................................................. 176 529.1 Scope .. ......................... ....................... ........................................ ....................... ... ............. . .. ............. 176 529.2 Bracing Members .......................................................................................... .................. ........................ .. .................. 176 529.4 Special Requirements ......................................................................................................................... ....................... 177 529.5 Beams and Columns ............................... .... ............................................................................. .. ................................... 178 529.6 Protected Zone .. .. ........ .. ....................... ..... ............................... ... ........... ............................................ ... ........................ 178 SECTION 530· SPECIAL PLATE SHEAR WALLS (SI'SW) ......................................................................................... 179
Nalional Structural Code of the Philippi nes 6'" Edilion Vo lume 1
'i.10 . I Scope .... ............ .. .. .......... ............ ............ .. .. ... . 'i30.2 Webs .'DO,) Conllcclion s oj' Webs {O Boundary Element s . .') )0.4 Horii'3.lfllal and Vertical BtltlJldilry Elements ...... ....... ..... __ ........... .
.. ... 17~ ...... . 179 .. ...... ... .179 .. ...... .. 17~
SECTION 5]1· QUALITY ASSUHANCE PLAN ............ ................................................................. ....... ......................... 180 5.1 1. 1 Scope ........ ...... .... ........................................................................... .................... ....... ........ .......... ...... ... ..
.. ........ 180
PART B· APPENDiCES ............... .......... ...................................................................................... ... ..... ........... .......... ... ...... . 180 Jl-!. PHEQUALIFICATION B·I . I Scope
OF BEAM·COLUMN AND LINK-TO· COLUMN CONNECTIONS ...................... .. 181
........ .......... ............. ............ ...... .. ..
8-1 .2 General Requirements B*!.4 Prcqualificmioll Variables.. B ~ J .5.
Design Procedure...
B ~ 1.6.
Prcqll,llil1c,ui oll Record ...
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.. .................. ..... ... ... ....... ... ...... ........... ... .. . ........ .... .".. . ................ .......... .. ....... .... . ...... ........ .... ....
. ......... 181 181 .. ...... .. ..... 181 . ....... .. 182 ..182
B-2. QUA L1TY ASSU RA N CE PLA N .............................................................. ................................ ....................... ........... 183 B·2 .1 Sco pe ... ........................................................................................ ..................................................................... ..... 18 3 8 -2.2 In spec tion and No ndestructive Tes ting Perso llnel. . . ..... ,....... .. ..... 183 13·2.3. COlllraclOr Doeumellls..... ....... ............. ................ .............. . ... 183 .. ................. 183 13 -2.4 Qualj( y Assurance Agc ncy Doculllcnts ................ .. 8 ·2.5 rn spcctioll Poillls and Frequencies .... . ... 183
11·3. SEISMIC DESIGN - COEFFICIENTS AND APPROXIMAT E PERIOD PARAMETERS .......... ....................... 187 B·3.1 Scope ........ ...... . B-3.2 Symbols
.. .. .......... .. 187 .. .. ......... ...... .... ... .......... .... 187
Jl·4_ QUALIFYING CYCLIC TESTS OF BEAM·TO·COLUMN AND LINK·TO·COLUMN CONNECTIONS ...... 189
B·4 .1 Scope .................. ..... . ............... .. ............................................ .. .... .. .. ........... . .. .. 189 .................... 189 B·4 .2 Symbo ls......... .. ........................................ . 8 -4 .3 Definitions .......... .. ........................... .. ........... . .. .. ...................... 189 B-4.4 Test Subasscmblagc Require ments .................... . ................... 189 0-4.5 Essential Test Variables ...... .... .... .. ... ................ .. .. ............... ... 189 .... 191 IJ·4 .6 Loading History. .............. ........ .. .......... .......... .. .... 191 B-4.7 Instrumentation . ................... .. .. ............ .. .191 B-4 .8 Materials Testing Requirements . ............. .. ........... . 8 -4 .9 Tesl Repol1ing Requirement s .... ... ... ........ .... ....... .. " ... .... .... .. ..... .................. ... ......... ........ ... . 192 193 B-4 . 10 Acceptan ce Criteri a ........... ... . ........ .. ...................... ... .... ................ ...................... .. ..... ............................... . B·S. QUALIFYING CYCLIC TESTS OF BUCKLING·RESTRAINED BRACES ........................................................ 193 B·5 . 1 Scope .. .............................................. .. .. ........................ ....................... ....................... ... ....... .. ............. .. ......... .. .......... 191 B·5 .2 Symbols ...................... ........................................... ... ... ... ............................ . ... ................. ... ... ...................... 193 B-S .3 Definitions... ...... ...... ... .................... ........ ............... .. .. 194 .. 194 13·5.4 Subassemblage Tes t Specimcn . ..19'1 13-5.5 Brace Test Specimen ......... ......... ............ . : 195 B-5 .6 Loading Hist ory.. . .............. .. .... .. ...... ........ ........ .......... ...... .. .. .. ............ .. .. .. . . .. 195 8 -5.7 Instrumentati on. .. . .. ............... .. .. . .. 195 .... ........ ...... .. .. B-5.8 Materials Testin g Requirements. .. ............ ........ .. ... .... ...... " ....... .... ... . .. .............. 196 B-5.9 Test Repon ing Requiremcms ............ .............. .. ................................................. . . .................. 196 B-5.10 Acceptance Criteria .............................. ................ .... .. .................. .. ............. ..... ............ .
B-6. WELD I NG PR 0 V lSI 0 NS ................................ ........................................................ .................................................. " 197 B·6. 1 Scopc ........................................................................ ............... ............. .................... ..... .... ................ ........................ 19',
B-6.2 Sll1lctural Design Drawings and Specifications, Shop Drawings, and Erection Drawings ............. .. ..... .... ......... ........ .. i en B-6.3 Personnel ..... ....... ..... .. .... ...... .. ................ .. ................. .. .... llJ7. B-6.4 Nondestructive Testing Procedures ... Association of Struclural Engineers of the Philippines
............................... .... .... 19~
13-6.5 Additional Welding ProvisicHls .. 13-6.6 Additional Welding Provisions for Demand Critical Welds Only ..
........ 19X ......... 199
n·7 WELD METAL/WELDING PROCEDURE SPECIFICATION NOTCH TOUGHNESS VERIFICATION TESTl99 B· 7.1 B-7.2 13-7.3 8-7.4
Scope ............................................................... .. Test Conditions .. Test Specimens .......................................................................... .. l .... Acceptance Criteria ...
. ....... 199 . ...... 200 .. 200 .. ..... 200
PART 2B· COMPOSITE STRUCTURAL STEEL AND REINFORCED CONCRETE BUILDINGS ....................... 201 DEFINITIONS ....................................................................................................................................................................... 201 SECTION 532 • SCOPE ........................................................................................................................................................ 202 SECTION 533 . REFERENCED SpECIFICA TIONS, CODES, AND STANDARDS ................................................... 203 SECTION 534 . GENERAL SEISMIC DESIGN REQUIREMENTS .............................................................................. 203 SECTION 535 . LOADS, LOAD COMBINATIONS, AND NOMINAL STRENGTHS ................................................ 204 535.1 Loads and Load Combinations .............. . 535.2 Nominal Strength ....................................................................... ..
.. .... 204 . .................. 204
SECTION 536- MATERIALS ............................................................................................................................................. 204 536.1 StnlCturai Steel ................................................. ... ... 536.2 Concrete and Steel Reinforcement ............... ..
.. 204 .. ...... 204
SECTION 537 • COMPOSITE MEMBERS ....................................................................................................................... 205 537.1 Scope... . ....................... .. 537.2 Composite Floor and Roof Slabs ... . 537.3 Composite Beams ......... .. 537.4 Encased Composite Colomns ........ 537.5 Filled Composite Columns
.. .............................. 205 .. ..... 205 .. ...... 205 . .................... 205 ... . ................ .. ... 207
SECTION 538 • COMPOSITE CONNECTIONS .............................................................................................................. 208 538.1 Scope ........................ .. 538.2 General Requirements ............. . 538.3 Nominal Strength of Connections ....
.. ...... 208 . ................... 208 . ...... 208
SECTION 539 - COMPOSITE PARTIALLY RESTRAINED (pR) MOMENT FRAMES (C-pRMF) ...................... 209 539.1 Scope ......... .. 539.2 Columns .............................................................................. .. ........................................................................... .. 539.3 Composite Beams
.. ............. ......... 209 ........ 209 .. ..... 209
....... 209
539.4 Moment Connections ...... .
SECTION 540 • COMPOSITE SPECIAL MOMENT FRAMES (C·SMF) ..................................................................... 210 540.1 Scope ......................... . 540.2 Columns. 540.3 Beams ...................................... .. 540.4 Moment Connections .. 540.5 Column-Beam Moment Ratio .................... ..
...... 210 . .. 210 .. .. 210 . .... 210 . ................................................ 210
SECTION 541- COMPOSITE INTERMEDIATE MOMENT FRAMES (C·IMF) ....................................................... 211 54 J.1 Scope ...................... .. ......... 211 541.2 Columns ........................... .. .. .................................... 211 541.3 Beams ........... ..... . ........................................................................................................ .. .. ................... 211 541.4 Moment Connections .. "" .............. . ................................ ............... .................................... ................... ............... 211 SECTION 542- COMPOSITE ORDINARY MOMENT FRAMES (C·OMF) ............................................................... 211 rh National Structural Code of tl're Philippines 6 Edition Volume 1
!)
B
CHAP"!"!: n:.:,
Steel (]n(J /·Act,jb
542. 1 Scope ......................... .... . 542 .2 Colulll lls ... .. ............................... .. ..
542.3 BeClllls .. 542.4 M ome nt COllllcelion s
.. ............ .... ......................... .. ...... .. .. .. . .... 2 11 .... .................. ... .... ........... .. ..... 2 11 .. ...... ............ ..... .... ............... .... .... ............................. .......... 21 1 ................................ ·........ 211
SECTION 54J - COMPOSITE SPECIAL CON CE NTRICALLY BRA CED
FRAMES (C-eBF) ............................. 211
543.1 SCOP" .... ........... ................... ................ .. ........................................................ .................... 2 12 543.2 COiUt11IlS ....... .......... ................... ................ .. .. ....... ............ ..................................... ............ 212 543 .3 Beams ................... ......... .. .... ............... ...... .... ......................... .. ........... 212 543.4 ilrace.s ........ .. ............ .......................... .................. ................ ............ ................................... .. ........ 212 543.5. Conllc(:lions.. ......... ..... ....... ... ......... .. .......... ................... .................. .............. ...... .,........... ...........·......... ... . 212
SECTION 544 - COMPOSITE OHDINARY BRACED FnAMES 544 . 1 Scope .................................. .... . 544 .2 Columns.. ................................ .. 544.3 Beams ...... ............................ .. 544.4 Braces ................................................................. ..
544 .5 Conneclions .......... ..
(C-OBF) ........................................ .................... 212
.. .................................................... 2 12 .............................................................................................. 212 ................ .. ............. .................. 212 .... ........ ........ .. ........... ............ ........................ 212 . ..................... ............................. .. ... 212
SECTION 545 - COMPOSITE ECCENTRICALLY BRACED FnAMES (C-EBF) .. ...... .. ............................................ 213 .. ............. .. .... .... 213 .. ........ . 213 .. ... ... 213 .. ............. 213 .. . . . 213
545. 1 Sco pe .. . 545 .2 Co lullllls .. 545.3 Links ........ ............................. ....... .. 545.4 Bra""s ......................................... .................... . 545.5 Connec[ions ..
SECTION 546 - ORDINARY REINFORCED CONCRETE SHEAR WALLS COMPOSITE WITH STRUCTURAL STEEL ELEMENTS (C-ORCW) .............................................................. .. ....................................................................... 213 .................. 214 .. ..... ............ 214 .. ............ 214 .. ............... 214
546.1 Scope .... .. .................................... ....... .. .. ................ . 546.2 BOllndary Members ... 546.3 Steel Coupl ing Beams ............. ".. 546.4 Encased Com posile Coupling Bcams ...
SECTION 547 - SPECIAL REINFOHCED CONCRETE SHEAR WALLS COM POSITE WITH STRUCTURAL STEEL ELEMENTS (C-SRCW) ............. ....... ................. ............. ................................. ........................ .............................. 215 547.1 Scope........ . ...................................................... ..................... ....... .... .... .. ........... .... 215 547.2 Boundary Members ................................................... .. .. ......... ............................. .. ............................................ 215 547.3 Steel Couplin g Beams ...................... .. ...... . ................................................................................. 215 547.4 Encased Composite Coupling Beams ...... ............................... .... .. .. ....................................... .... ...................... ... 215
SECTION 548 - COMPOSITE STEEL PLATE SHEAR WALLS (C-SpW) .................................................................. 216 548 .1 Scope. ........................... .. ..... .............................................. ........................................... .. ........ .......... ............... 216 548 .2 Wall Elements.. ... . ............................................................... _...................... ..................................... 216 .. ........................................................ 216 548.3 Bo undary Members ... ............... " .... .... ......................................... ............... . ..................................... .. 2 16 548.4 Open in gs. ....... .. ............... .. .... ........ .. ..... ... .............................. ............. .
SECTION 549 . STRUCTURAL DESIGN DRA WINGS AND SpECIFICA nONS, SHOP ORA WINGS, AND ERECTION ORA WiNGS" ........................................................... ..... ................................ .. ........... ....................................... 21 7 SECTION 550 - QUALITY ASSURANCE PLAN ....... .............................................. ........ .... ..... ....................................... 217 PART 3 - DESIGN OF COLD-FORMED STEEL STRUCTURAL MEMBERS ........................................ ................... 2I ~ SyMBOLS ................................................... ........................................................................................................................... 2L DEFINITIONS ........................................................................................................................................................................ 22-"1 SECTION 551· GENERAL PROVISIONS ........................................................................................................................ 228 551.1 Scope, Applicability and Definitions ................ .... .......................... ..
.................. ........................ .................. 228
Association of Structural Engineers of the Philippines
55 1.2 Material ........................................................................................................... . .................................................... 22<) 55 1.2. 1 App li cable Steeb ......... .. .................................................. ..... ..... ............. ......................... .... ............ .... 22~ 55 1.3 Loads .................... . ................................................................................................................................ ........... 231 55 1.4 Allowahle Strength Des ign .................... ............ .................................... . ............................................... .......... 2) I 551.5 Load and Hcsis(;.IIH:C Fal:lOr Design ................................................ ".... ... ........... ..... ................ ..... 23 1 551 .7 Yield Siress and Strength Increase from Cold Work of Forming . ............... .. .. ......................... .212 55 1.B Serviceahi lity. .......... ........... . .............. .. .. ............... ............................... ... ... ..... .. ... 2J2 551.9 Referenced Doculllents ..... ....... ............................. , . ... ....... .. ............ .... . 232
SECTION 552 - ELEMENTS ........................................................................................................: ................................. ..... 234 552. J Dimcilsiorwi Limits .lIld Considerations ... ....................... .................
............ ......................................... 234 552 .2 Effective Widths I)f Stilfened Elements ...................................................... .......... ....................................................... 235 552.3 Effecti ve Widths or Ullstilfcllcd Elements ................................................. ................................................................... 238 552.4 Effeclive Widlh of Uniformly Comprc~scd Elcmcllt~ wilh a Simpl e Lip Edge Stiffener ......................................... "." 240 522.5 Effective widths of Stiffened Elcmcnls Willi Single or Multiple Intcnllcdiale Stiffeners or Edge Sti lTened Elements with In lcnncdiate Sliffc l1cr(s) .......................................................... ............................. ................................ , ...... , ........ 241
SECTION 553 - MEMIIERS .. __ ........ _......... _............... _......_.. __ .. _......................... _.. _......................................... _.................... 243
I ,
or
553. 1 Propcnics Sections , ....... ........... ........ .. ...................... ............................................................................................... 243 553.2 Tension Member.; ......... .. .......... .. .................................................................................................................. 243 553 .3 Flex ural Menlbers ...... ,... .. ........................ ,..... .............. . ... ..................................... 24] 553.4 Conce ntri cilily Loaded Compression Members .. ..................... .. .................. 259 553.5 Co mbilwd Axi,ll Load and Bending.. .............. . ................ .. ....... 262
SECTION 554 - STRUCTURAL ASSEMBLIESAND SySTEMS ................................................................................... 2G5 554. 1 Built-Up Sections.. .................................... ................ .... .. .............. .. 265 ................ .......... .... .. .. .. ......... .............. .............. ...................... ...266 554 .2 Mixed Systems ........... 554.3 Lateral and Stability Bracing .... .................... ............. ................. .. .............................................. 266 554.4 Cold -Formed S teel Light-Frame Construction .......................................... ... .. ................................................ 268 554.5 Floor. Roof. or Wall SteCi Diaphragm Construction ...................... ,............. .. ............................................ .............. 268 554 .6 Metal Roof aud Wall System .... .................................................................................................................................. .. 269
SECTION 555 - CONNECTIONS AND JOINTS ...... ...... _.. _..................... _......... __ ..... _...... _................................................ 275 555.1 General I'ro"isions .......... ............................................................................... ..... ........................................................... 275 555.2 Welded Connections .............................. ................................................ ............................... ......................................... 275 555.3 Bolted Connec ti on ......................................................................................................................................................... 28 1 555.4 Screw Connections ............................. ........................................................ .. .. ..... ...... .. .................................. ... .. 283 555.5 Ruplure .................................. ...... .................................................................... ..... ......................................................... 285 555 .6 Connecting to Other Materials .. ...... .... .......................................................... ............. .................................................. 286
SECT/ON SSG - TESTS FOR SPECIAL CASES ....... _........ _.............................................................................................. 286 556. J Tests for Determining Structural Performance .. . ....................... . .......... .... ................. ... ................. .. .... 286 556.2 Tests for Confirming Structural Performance" .. "........................ .... ...... .. ............. ".".......... .. ... 288 556.3 Tests for Determinin g Mechanical Properties ." .................... ".............. .. .. ..................................... . . " .,288
SECTION 557 - DESIGN OF COLD-FORMED STEEL STRUCTURAL MEMBERS AND CONNECTIONS FOR CYCLIC LOADING (FA TIGUE)................................ ....... .................... ................................... ........................................... 290 557. 1 General ................................... ..... ................................................................................................................................. 290 557.2 C
SECTION C-I - DESIGN OF COLD-FORMED STEEL STRUCTURAL MEMBERS USING THE DIRECT STRENGTH METHOD .................. _................................................................................................................. .................... 292 C-I Design of Cold-Formed Steel Structural Members Using the Direct Strength Method .................................................... 292
1h
National Structural Code of the Pil ilippil10S 6 Edition Volume 1
SECTION C·2 . SECON()·ORnEIt ANA I. I'SI'S ........... .................................................................. .................................. 299 C.2. 1 Gellera l HcquirclIlcllts ...................... . C.2.2 Design and Ana lys is COIlSII':li IlI S ....... .
................................... ········ ....... 299 ............................ .. 299
SECTIO N C3 - Af)()ITlONAL PROVi SiONS ... ... ............................. ... ........ ......................... : .......................................... 300 C.3.1 Scope . ................ . ......................... .... 300 C.3.2 Olhor Sle
Association of Structural Engineers of the Pllilippines
CHAPTERS STEEL ANI) l\1J!:TA~S
SI'ECIFICkttQNEQR STRUCTURAL STEEL BUILDINGS
A;, AJ.~ A1;, Aji
A, . Ag
The Specification for Structural Steel Buildings, hereafter referred to as the Specification, shall apply 10 the design
of the structural steel system, where the steel elements arc defined in the AISC Code of Slttlidard Practice for Steel Buildings and Bridges, Section 2.1.
This Specification includes the following Part I
Specification for Steel members
Part A
Appendices for PaIl 1
Fal12
Seismic Provision for StJ1lctural Steel Buildings
A, AJ ,
/llJll
Part 2A Structural Stee! Buildings - Provisions Part B
Concrete Buildings
A, A"
Part 3
Specification for the Design of Cold-Formed
Steel Pan C
StJ1lclural Members
AI\"
A"'i
Appendices for Part 3
PART 1 SPECIFICATION FOR STEEL MEMBERS
A, A, /J
SYMBOLS
Alii
A, A,
Cross-sectional area of the overlapped branch, 2 mm Area of COllcrete, mm 2 Area of concrete slab within effcctive width,
mm B
Overall width of rectangular I-ISS main member, connection, measured 90° to the plane of the
B
Factor for lateral-torsional buckling in tees and double angles Overa!! width of rectangular HSS branch member, measured 90° to the plane of the connection, mm Overall branch width of the overlapping branch Overall branch width of the overlapped branch. V.,lidth of plate, transverse to the axis of the main
mm
111m2
Il1m?
Area of an upset rod based on the major thread diameter, 111m2 2 Effcctive net area, mm Summation of the effective areas of the cross section based on the reduced effective width, b ,', mm
Stiffener area, mm~ Net tensile area, 111m2 Web area, the overall depth times the web thickness, til", , 1111112 Effective area of the weld, mm 2 Effective area of weld throat of any ith weld element, mm 2 Area of steel concentrically bearing on a 2 concrete support, mm Maximum area of the portion of the supporting surface that is geometrically similar to and concentric with the loaded area, 111m2 Overall width of rectangular HSS member, measured 90 to the plane of the connection, Q
Column cross-sectional area, mnl Total cross-sectional area of member, nun:? 2 Loaded area of concrete, mm Cross-sectional area of the base metal, mm 2 Nominal unthreaded body area of bolt or threaded part, mnl Cross-sectional area of the overlapping branch,
AI)
2
Shear area on the failure path, mill:: Area of continuous reinforcing bars, Illm~
Appendices for PaIt 2
Part 2B Composite SIJ1lctural Steel and Reinforced
Area of compression llange, Illrn~ Gross tension Hange area, tnm 2 Net tension flange area, !lln/ Area of tension flange, IYIm 2 2 Gross area of member, rnm Cjross area of section based on design wall thickncss mm! 2 Gross a'r~~l of composite member, Jl1m 2 Chord gross area, mm J Gross area subject to shear, Illm Net area of member, 111m2 2 Net area subject to tension, mm Net area subject to shear, 111m2 2 Projected bearing area, mlll Area of adequately developed longitudinal reinforcing steel within the effective width of the concrete slab, 111m2 Area of stcel cross section, mm? Cross·sectional area of swd shear connector,
member, mm
c
Factors used in determining Mu for combined bending and axial forces when firsl-order analysis is employed HSS torsional constant
2
111
National Structural Code of the Philippines 6 Edition Volume 1
c,.
(,
1.:ttt:r;ll-lorsional buckling lllodifit,lI ion factor for nonu niform momCIH diagrams when hoth
F,.,
ends of (he.' unsupported segment ;lrc braced
I;/:x,\"
COCfriC iCll1 rclaling rela tive brace stiffn ess and
1':.,.
axis, MPa
t.:U(V;IHJrc
COm>lil1l1 lHlscd 011 slress ca tegory. giVl'1l in
Table
501').1
Coefficient assu ming no lateral tr;lll slalion of th e
frame Ponding
c. C,
C,. Cn· D
ncxibilit y
coefficient
fo r
primary
member in a flat roof
Coefficient for web 5idcsway buckling Ponding flexibility coefficient for second.try
member in a flat roof Web shear coefficient Warping constant , rnm ('
f)
Nominal dead load Outside diameter of round HSS member.
f)
Outside diameter, mill
D
!Hill .
Ou tside diameter of round HSS main member. 111 III
D
Chord diameter. mm
D"
Outside diameter of rOllnd I-tSS branch meJ1Jber.
E
Ec
F
"
P"
mill Factor us ed in Equation 507 .3 -), depe ndent on type of transverse stiffeners used in a plme girder In slip-critical co nn ections, a multiplier that rencets the ratio of the mean installed bolt pretension (0 the specified minimum bolt pretension Modulus of elasticity of steel = 200 000 MPa Modulus of elasticity of concrete =
JT:.
0.043w/' MPa Modulus of elasti ci ty
or
concrete. at elevated
1'.
te mperatu re, MPa.
Es F"
Elastic nl!xul"ill bllc~ling stl"l'SS about the major axis. MPa ElcCll"odl! class ification number, MPa Elastic l1exural buckling stress about the minor
Effective stiffness of composite section, N_mm 2• Mod ulus of elastiCity of steel at e1evatcd temperature, MPa Modulus of elasticity of steel =200 000 Mra Available ax ial stress at th e. point of consideration, MPa Nominal strength of th e base metal per unit area, MPa Available flexural strc.ss at the point of consideration about the major axis, MPa Ava ilable flex ural slress at the poi nl ' of consideration about the min or axis, MPH Available stress, MPa Critical stress, MPa Buckling stress for the section as determined by analysis. MPa Critical stress about the minor axis, MPa Critical torsional buckling st ress, MPa EI:!stic critical buckling stress, MPa
F,
Elastil.' torsiollal huck ling stress. MP" A caltu latcd strcss lIsed ill the calculation of nominal flexural strength. MPa Nominal torsional stre ngth Nominal tensi!!: ..:trcss Fill ,or shear stress, rnv from Table: ) I 03.2. M I'a Nominal tcnsile strc.'iS from T of Il l"':' overlapping bra nc h material, MPa Specified 1l1immUIl1 yield ~t rcss of I!!:' overlapped branch materi al, MP;l
Association of Structural Engineers of the Pllilippines
F'f
Specified minimum yield st ress of the flange.
I.
MP" PI''''
Speci fied minimuill yie ld stress of the I)'I>C of steel heing used al ele vated IcmpcralUrc. MPa Speci fi ed minim um y ield ~>lrCSS of plate, MPa SpcciJi cd minimulll yield stress o f reinforci ng
bH fS, MPa Spccilicd minimum yield stress of the stiffener material . MPH
"iJ'
Specified minimum yield stress o f the web. MP;l She;lf modulus of elasticity of steel :: 77 200 Ml'a Story shear produ ced by the lateral forces used (0 co mpu te II JI N Overa!1 height of rectangul ar HSS member, measured in th e plane of the connection, 111111 . Overall height of rectangu lar HSS main member, measu red in the plane of the connec li on, mill.
L•.
I
H H
N
Flexural constant.
iii,
Ove rall height of rectangul ar !-ISS bmnch member, measured in the pl a ne of lhe co nnec ti on. 1111ll . Overall depth of th e overlapping branch. Moment of inertia in the place of bending, mm~ . Moment of incllia about the axis of bend in g,
, nUll .
I.
I" I" Is I, I"
I), • I,.
I,. . I, I),
j
K K,
K,
L L L
L L
L
Moment of inertia of the concrete section. mllf1. Mome nt of inenia of the steel deck supported 011 seco nd ary members. mm4. 4 Mome nt of inertia of primary members, I11m , 4 Moment of inertia of secondary members, 111 III . Moment of inertia of steel shape, mm", Momen t of inertia of reinforcing bars, rnm4. Momen t of inertia aboU\ the principal axes. I11m4 . Out·of-planc momcnt of inertia. 11111l4. Minor principal axis moment of inertia. nlln4. Moment of inertia about y-axis referred to the compression flange, or if reverse curvatu re bending referred to smaller flange , mm4. Torsional constant, mm4. Effect ive length factor determined in accordance with Section 503. Effect ive length factor for torsional budding. Effective length factor in the plane of bending. calcu lated based on the assumption of no latera l translation set equal to 1.0 unless analysis indicates that a smaller value may be used . Effective length fac tor in the plane of be ndin g, calcu lated based on a sidesway buckling analysis. Story height, mm Length of the member. mill. Actual length of end-loaded weld, mm . Nominal occupancy live load. Laterally un braced length of a member, 111m . Span length, 111111.
1..."
l.pi'
Length of" member between work POilllS a\ truss chord cenlcrlincs. mill . Length bctwc('!1 points that :If(~ cit her hr:u:cd against lalerClI di sp lt of the l.TOSS
secti on, mill . Distance between bnl(.·cs. 111111 . Length of channel shca r co nll ector. Illlll. Clear dis tance. in the direction ~)f thc force , between the cdge of the hole and \I;~ edge of the adjacent hole or edge of the mate ri al. mill. TOlal effective weld length of groove and fillct welds to rectangular HSS. mm. Limiting laterally unbraced lengt h for the limi t slate of yieldi ng mm. Column spacing in direction of girder. m. Limiti ng laterall y unbraced length for plastic ana lysis, mm . . Maximum unbraced length for Mr (t he reqUIred ll exural strength ). mm .
L,
L,.
M il M b, Me
M•..•
M"
M, M,.
M,.
Limiting laterall y unbraccd length fo r the limit Slate of inehlsti c latera l-torsional bucklin g, mill . Column spacing perpendi cul ar \0 direc tion of girder, m. Distance from maximum to zero shear force. mm. Absolute va llie of moment at quanel" point of the unbraccd segment, N-mm Required fle xural strength in chord, usi ng ASD load combinati ons, N-1ll111 Absolute value of moment at centerline of the unbraced segment. N-mITI Required bracing moment. N·mm . Absolute value of moment at three-quarter polin of the un braced segment, N-mm A vailable flexural strength determin ed III accordance with Secti on 506. N-mm Available Oexural-lorsional strength for strong axis flexure determined in accordance wi th Section 506, N-mm Elastic lateral-torsio nal bucklin g moment. N-mm First-order moment under LRFD or ASD load combinations caused by lateral translat ion of. the frame only. N-f11Tn Absolute val ue of maximum Illomelll in the un braced segillent, N-mm Nominal flexural strength, N-I1Ull First-order moment using LRFD or " SD load combinations assuming there is no lateral translation of th e frame, N-mm Plastic bending moment. N-nun Required second-order flexural strength under LRFD or ASD load combinati ons, N-ml11 Required fiexural strength using LRFD or ASD load combinati ons, N·mm Required flexural strength in chord , N-mln
th
National Stru ctural Code of til e Pll ilippines 6 Edition VO!lJnlC 1
. ..
.~,> \,
,
~
M, 'f'
R cq llir~d in-plant.' Ik xura l st rength ill branch.
/'
N- 1Il1ll
1',
Rcqui rt.'d ow-or-plant' flexural strcngth in hnllich . N- mm M" Required l1 exllral strength in chord_ using. LRFD load cornbil\iII i on~. N-1ll1ll . M, Yield moment aholJt the
j
P" 1', (i
00
/I /I
/I" NUl.
/I",
R"
Rcq ui rnl
RII R'I
R, " R"JI'
N fl/
R"'f
S S S S Sc
Sy T
Nomina! slip resi sta nce, N Position erfect factor for shea r studs Web piast ifi cat ioll factor Reduction factor for reinforced or nonrcinforced transverse pani al"joilH"pcnetralioJ) (PJP) groove welds Web plastificalion faclOr corresponding to the tension nange yielding limit Slate Required strengt h Total nominal strength of longitudinally loaded fillet welds, as determin ed in accordance with Table 5 10.2.5 Tala.! nominal strength of transversely loaded fillet welds, as detennined in 'lccordance wil h Table 510.2.5 without the alternate in Sect ion 510.2.4 Elastic section modulus of round HSS, Illml Lowest elastic section modulus rel
Association of Siructural Engineers of Ihe Philippines
CHI\PTEH :J . Steel and Met HI s
. he width b is th e distant:e from the free edge to '-:!stcHers or line of we lds , o r the d i 'itancc bc t wc<.~ 11 adjacclII lines or fa ste ners o r li l ~ cs of welds: fo r rectang ul ar HSS , the widt h b is Ille clear di stance between the webs less the insi de corner radills on each side, mill Wid!.!j of thl! angle leg resisting the shew' for ce, mm Width l)f column fl ange, mm Rcducuj erfec tive width, mm Effecti ve edge distance; the distance from the edge of t l}(~ hole to the edge of the pari me asured in the di recti on norma l (0 the applied force, m m Effective w idth or the branch face welded to the chord Effe.Cliw 'wi dth of the branch face welded to the Qverlapp<,'d brace.
Tensioll force due 10 ASD load combinations, kN
Min im um fasten er SIOJ. I ,kN
tens ion
g ive n
in
I 'le first row of
Table
Available tors ional strength, N-Ill!ll Nomin:d IOrsiona l strength, N-IllJ11 Required torsional strength, N-Il1J11
h
Tension force.: due to LRFD load combi(1alions, kN
h'i
b,
u
Sheil!' hig (;II.:lor Utiliz
U.,
Reduc tion coefficient. used in calcul ating bloc k s hear rupture strength Stress index
b ..... ,
U, V
Stress index
bN W
V'
Required shear force transfen"cd co nn ectors, N Available s hear streng th , N
u u,'
V,
V" V,
v, v, )',
Z
z, a
bItT
Required shear force introduced to colu mn, N
by
shear
Nominal shear st rength. N Req ui red shear strength eH the locati on of the
stiffener, N Required shear strength usin g LRFD or ASD load combinations, N Gravit y load from the LRFD load co mbination or J.6 tim es the ASD load combinmion applied at level i, N Hole re du cti on coefficie nt, N Plasti c secti o n mod ul us about the axis of bending, mill) Branch plastic sectio n modulus abou t the correct axi s of be nding, 111111" Plastic sec tion modulus abou t the principal axes, J mm C lear d istance be twee n transverse sti ffeners,
b,
" a
D islallCC between cOll nectors in a built -up member, 111111 Sh0l1 est di stan ce from edge of pin hole to edge of member measured parallel to direction of force, mm Half th e length of the nonwelded root fa ce in the direction th e th ickness of the te nsio!l-loCl ded
or
bf , hI b" b, d d d d
Nominal fastener lliametcr, mm Full nominal depth of the section, mill Full nomin a! de pth I 'f tee, 111111 Depth of rectangular bar, 111m
d d
Full nonunal depth of It 'C, mm
d d d
dlJ d
ti," l!
e"""'!'1
ii!
plate, Illlll (1,,-
/, b b
Rat io of two times the web area in co m press ion due to appli cati on of major axis bendi ng moment
alone lO the area of the comprc.o.;sion !lange components Outside width of leg in compression, Illlll Full width of longest angle leg, mill 'Widt h o f ullstiffcncd com pression e leme nt ; for fl anges of I-shaped members and tees, the widt h b is ha lf the fil II -flange width, bf ; for legs or angles and flanges of cha nn els and zees, the width b is the full nominal dim ension; ror plates,
Flange w idt l), mm Compression nangc width, 111 m Width oftensiv il fl ange. mill Longe r leg of a f, gle, mill S honeI' leg o r .11} /~Je. mill Stiffener width for o ll e-sid ed stiffeners, 1111ll
"f,'
111111 .
a
S· l:i
Full nominal deplh of ",cctlon, 111m
Dinmeter, 111m
Pin diameter, mill RoBe r diameter, mill Beam depth. I11Ill Nominal diameter (body or sl .:mk diameter), Illill Column depth, mOl Eccentricity in a truss c.;oll llectic..·n. positive being away from the branches, m ill Dist
.Ii"",. :,
combinations. MPa Required fl ex unl l stress .11 {he point 0 1 considerat io n (major .. xis. minor axis) using
/'c.
Spec ifi ed minimulll co mpress ivc stlcngth of
LRFD or ASD IO
[ 1'1"
J, j.,
N,'ltional Structufi::11 Code of the Philippines
conc rcte., MPa Spec ified minimum compressive stn 'ngth or concrete at clevtt tc temperatures, MPa Slress due to D + R (the nominal dead lead + tloc nominal load due to minwater or snow c.xcl lls ive of the ponding contribu tion), MPa Req uired shear st rength pCI' unit area, 1\1]> 1',
Gi ll
h@on Volum e 1
5· 1(j
g
g
"
" ",.
h" II f'
h~, .
j
k k
k,. k.\
CHAPTEn
~l
. St(wl and Metals
Transvc rsL' c:.:cntcr-h>-rcnter spadng tgage) between fastener gage lines, 111m Gap hetw(.~cn lUes of branch members in a gapped K- co nnc ctioll, neglecting th e wdd s, 111m Clear distance between /langes less the liJIel or corner r.adius for rolled shapes; fl Jr built -up sections. the di stance between adj(l( ellt li nes of fasteners or the dear distance bct v.'ccn Jlangcs when welds arc used; for tCC!'i. the ove rall depth; ror rectangul;is or buckling, mill Twice the di sta nce from the ce ntroid {o the following: the in side face of the co mp res sion nangc less the fillet or corner radius , for rolled shapes; th e nearcs t line of fasteners at the compression nangc or the ill side faces of the compression l1ange wh en welds arc used, for
builHIj> secti ons, mm Distance between flange .;cnt roi ds, mill Twicc the di slallce frolll the plastic neutral axis to thc nearest line of faste ners at th e co mpression llallge or the inside face of the compression nange when welds arc· used, mill Hole factor Factor defined by Equation 507.2 -6 for minimum Ploment of' incniH for a transverse stiffcnr r. Distance from ouler face of flange to the web toc of fillel, mm Outside corm:.r radius of the HSS, which is permitled 10 he taken as I.St i r unknow n. Illlll Coefficie nt tor slender ullstiffened clements, mill Slip-criti c.ll combined ten sion and shear coe ffici ~ nt
k,_ I
II II
p
q r
r,
radius
of
gyrat ion
of individunl
component in a built-up rncmht.:L I11Ill Radi us or gyralU)1I uf indi vidu al co mponent relative (0 its centroidal axis paralkl 10 member axi s of buckling. mill r oO
Pola r radius of gynllion alHHIl the shear t.:c ntcr, n1l11
r,
Radius of gyralion oj" the !lange comp(1)L!llls ill flexur;!l compression plus one-thi rd of the web arca in cumpression due to app lil;alion of maj or axis bending mome nt alone Effective radius of gyration used in th e Lr for the lateral-torsional determination buckling limi t stale fo r majo r ;is bending of doubl y symmetric compact I-shaped members ilnd channels Radius of gyrati on aboul geometriC axis paraUcl
or
r, r, r
to connected leg. mill Radius of gyra ti on about y-iIXis, mill
Radiu s of gyrati on for the minor principal axis, ml1l
Longitudilwl ccnter-iQ-(;CIHCr spacing (pitch) of any two consecutive ho les, mill Thickness of clemen!. mm Wall thickl1 ess, mill Angle leg thickness. mill Width of rectangul ar bar parallcl to ilxis or bending. 111m Thickness of connected material, 111m Thickness of pliitc , II1Ill Design Willi thi ckne ss for HSS equal to 0.93 times the nominal wall thickness for ERW HSS and equal to [he 110minal wall thickness ror SA W I-ISS,
Illill
Total thickness of fillers, mill
r"
Web pl,ale buckling coefficient Largr st laterall y unhraced length along either flan i!-c at the point of load , mm L(' nglh of be.aring, mill tl'nglh of cOll nection in th e direction of loading, 111m Number or nodal braced points within the spa ll
Threads per mill RHtio of cleme nt i deformation to its deformation at maximum stress Proj ected length of the overlappin g branch o n the chord O vcrlnp le ngt h lIlea:mrcd along the connecting face of the chord bene at h th e t wO branches Governi ng radius of gyratio n, mm Distance frolll instantaneous cellter of rOlation to we ld clement with minimum u hi ratio, nun
Mini mum
t". I,..
Design wall thi ck ness of HSS ma in membe r, mm Design wall thi cknes s of HSS branch member,
mm Thick ness of the overla pping branch. I11Ill Thickness of the overlapped branch. mm Thickness of the column nan ge, Illlll Thicknes:-; of th e loaded flange, Illlll Flange thickness of channel shear co nnector, mm Compression flange thickness. mill Thickness or plale, 111m Thickness of ten sio n loaded plale, mm Thick ness or the .Htac hed transverse pl at(~, Jllin Web sliffener thickness. mill Weh lhickness o f ciw lln c l :-;hear conncctor, I11Ill Beam web thickn ess, 1ll1ll Web thickness, mill Column web thickncss. 111111 Thickness of clement, 111m
\I'
Width of cover plate, Inm
\I'
Weld leg si ze, mill
Association of Structural Engineers of the Philippines
CHAPTEfi 5 . Steel and Metals
{/
Subscript relating symbol to major principal axis bending Plate width, mill Leg size of thl' reinforcing or contouring ri Ilet , ir any, in the direction of the thickness or the tension-loaded plate, mm Weight or COJlcrete per unit volume (90 '.s II', < 1 155 Ibsm or 1500 W,':' 2500kg/m\ A vcr-age width or concrete db or haunch, mm Suh'\'Tipt relating symbol to strong axis Coordinates of' the shear center with respecI to the centroid, mm Connection eccentricity, mill Subscript relating symbol to weak axis Subscript rclating symbol 10 minor principal axis bcnding FaCIOI' uscd in 132 equal
1/
Scparation
II'
w, 11',
x
,\
Y
ratio
for
built-up
Gap ratio; the ratio of the gap between the branches of a gapped K-connection to the width oj" thc chord for rcctangular HSS Load length parameter, applicable only to rcctangular HSS; the ratio of the length of contact 'of the branch with the chord in the plane oj" the connection to the chord width Slenderness parameter Limiting slenderness parameter for compact clement Limiting slenderness parametcr for compact nange Limiting slenderness parameter for compact web Limiting slcnderness parameter for noncompact element Limiting slendcrness parameter for noncom pact flange Limiting slenderness parameter for noncom pact
'/
compression
web
members:;;:; __ .12......" 2rib
/1 /1
/1,
If"",1 jJ"",
/1"
Reduction factor gi ven by Equation 5 J 0.2-1 Width ratio; the ratio or branch diameter to chord diameter for round HSS; the ratio of overall branch width to chord width for rectangular HSS Brace stiffness requirement excluding web dist0I1ion, N-Il1Il1/radian Rcquircd brace stiffncss Effective width ratio; the sum of the perimeters of the two branch members ill a K-conncction divided by eight times the chord width Effective outside punching parameter Web distor1ional stiffness, including the effect of web transverse stiffeners, if any, N-mmlradian Section propCI1y for unequal leg angles, positive for short legs in compression and negative for long legs in compression First-order interstory drift due to the design loads, mill First-order interstory drift due to lateral forces,
mm
.1"
)'
5·17
Deformation of weld elements at intcrmediatc stress levels, linearly proportioned to the critical deformation based on distance from the instantaneous center of rotation, ri, mm Deformation of weld clcment at maximum stress, mm Deformation of weld clement at ultimate stress (fracture), usually in clement flU1hest from instantaneous center of rotation, 111111 Chord slenderness ratio; the ratio of one-half the diameter to the wall thickness for round HSS; thc ratio of one-half the width to wall thickness for rectangular HSS
()
o
",
Mean slip coefficient for class A or B surfaces, as applicable, or as established by tests Resistance nlCtor, specified in Section 502 through 5 I 1 Resistance factor for bearing on concrete Resistance factor for flexure Resistance factor for compression. Resistance factor for axially loaded composite columns Resistance faclOr for shear on the failure path Resistance factor for torsion Resistance factor for tension Resistance factor for shear Safety factor Safety factor for bearing on concrete Safety factor for llexure Safety factor for compression Safety factor for axially loaded composite .columns Safety factor for shear on the failure path Safety factor for torsion Safety factor for tension Safety factor for shear Minimum reinforcement ratio for longitudinal reinforcing Angle of loading measured from the weld longitudinal axis, degrees Acute anglc between the branch and chord, degrees Slrain corresponding to compressive strength, f'c Parameter for reduced flexural sliffness using the direct analysis mel hod
1h
National Structural Code of the Philippines 6 Edition Volurne 1
,
1))4
1
5 -18
CHAP rER 5 . Steel and Metals
BATTEN PLATE. Plcne rigidl y cunnected to t \Yu pamllel components of a buill-up colulll ll or be a:?l designed LO tra ns mit sht.:iIf between the (;umpOllcnt:o.. Terms thilt appear in this Glossary are ifalicizn/ throughout the Specification, where they first " ppe:lr within a sub -section.
BEAM. Stnu:tura l member IlwI hilS the primilry fUIlClioll of resisting bending mome nts.
Now.\'.'
BEAM-COLUMN. Structural member Ihat resists both axial force and bending Illomenl.
J.
7l' rtI ' \' designated wilht art' common AISI·AISC term.\' thai are coordinated bellveen thl' two sta" r/ardJ developers.
BEARING. In :1 boiled co nnec lion, limit stale 01 shear rorces transmitted by th e bolt to the con nectio n clements.
2.
Terms desig nated with * are usually qualified hy Ille type of load effeel, for example. lIominoi tel/sile strenglh, available compressive slrclIglh, design flexural.'itrenJ.:lh.
BEARING (LO CA L CO MPR ESS IVE YIEL[)[NG )_ Lim it state of loca l compressive yielding due to the ac ti c!: of a member bearin g against another member or slllfacc.
3.
Terms desig nated with U ore usually qualified by the ryp e oj compOIlt'Ilf. for examplt>, web local buckling. JIlmge local bending.
BEARING-TYPE C ONN ECTION_ Bolted conncction where shear forces are trans mitted by the bolt bea ri !:;.! ag.linst (he conn ecti on c lement s.
ALLOWABLE STRENGTH_ Nominal strength dividcd by th e safety factor. R "I D.
BLOCK SHEAR RUPTU RE. In a connecti on, li mit state of tension fra ctu re alo ng o ne path and shear yielding or shear fracture along another path .
ALLOWABLE STRESS. Allowabl e strcngth dividcd by the app rop ria te section property, such as secti on mod ul us or cross-secti on area. AMPL IFI CA TION FACTOR Multipli cr o f the resu lts o f first-order ana lysis to reflect second - o rder efrccts _ AS!) (ALLOWABLE STRENGTH DES IGN). Mct hod of propol1ioning stmc tural components slI ch thaI the allowable st rength equals or exceeds the required strength of the component under the ac tio n of th e ASD load combinations. ASD LOAD COMllINA TION _ Load comb inati o n in th is code intended for allowable strength design (a llowable stress des ign)_ HAVING JURISDI C TION. AUTHORITY Orga ni z:lIion. political subd ivision, office or indi vidua l charged wi th the responsibility of admi ni stering and enforcing the provisio ns of thi s code. AVA ILABLE STRENGTH _ Des ign allow:tble strength, as appropriate.
strength
or
AVA ILAB LE STR ESS_ Dcsign strcss or allowahle stress, as appropriate. AVERAGE RIB WIDTH. Average wid th o f the ri ll of a
corrugat ion in a fonned sleel deck.
BRACED
FRAME.
An essent ia ll y vertical tn: resistance to latera! forces ;''''~ provides stabilit y fo r the structural system.
sys tem that provides
BRANCH FACE. Wall o f HSS branch I11cmber. BRANCH M E MBER. For !-ISS co nnecti ons. melll! ,. _ th ai tem1inatcs at a chord member or main meil iber.
BUCKLING. Limit state of sudden change in I ~ ;C geometry or a structure or an y of its clements unde: i. cri tical loading condition. BUCKLING STRENGTH. Nomina l buckling or instabilit y limi t stales.
strength
for
BUILT-UP MEMBER, C RO SS-Snr";'!c; : '. SECTION, SHAPE. Member. cross-s",:ti"n. ,,-," ,-,: shape fabricated from structural stee l ~:, 'I1I {" JiI -; i- .: weldcd or bolted together. CAMBER . Curvature rabricated int o ;t hC; ! ~1 ·1 (' 'rll ~s so a~ to compensate fo r denection indt :~l~ d by III .. i:;. C!-IARPY V-NOTC H IMPA CT dynamic test mc;tsuri ng notch specimen.
T EST. I\;~ :: L!lt';';,
CHORD MEMBER. For !iSS. pri.:. :.::.extends through a truss co nn ecti on.
Associa tion of Stru ctura l Engineers of the Philippin es
St.. "d"rd
CHAPTE:li 5 . Sleel and Metals
CLADDJNG. E Xlcrior cove ring
or slrLl(; llI rc.
COLD·FORMED STEEL STRUCTURAIL MJt:MIIEn . Shape manufaclu rcd by press-bnlking blanks shc
COLUMN. Stru ctural member that IHI!; the primary function of resisting (lxi nJ forcc. COMDINED SYSTEM. StnlCture comprised of two or more lateral load-resisting syslems of diffe rent type. COMPA CT SECTION. Section capable of developing .a fully pi. CONNECTION. Combination of struc tu ra l eJemeHls and joints used to trall!;mi t forces between two or mo re
5 19
CROSS CONNECTION. HSS co nn ec ti on in which forces in bran ch members or connecting cle meJlt s transve rse to the main member are primarily equili bra ted by forces in otliel' bra nch members or connecting elciTlcn l ~ 011 the opposi te side of the mai n member. DESI GN LOAD. App lied Iliad detcnnincd ill accordance with either LRFD load co mbinati ons or ASD load combinations, whichever is applicable. DESIGN STRENGTH. Resistance factor multiplied by the nominal stren gth. ¢RI!. DESIGN STRESS RANGE. Magnitude of change in st ress due to th e repeated appli cHtion and removal of service live loads. Por locations subject 10 stress reversa l il is the algebraic difference of the peak stresscs. DESIGN STRESS. Design strength divided by the appropriate sec tion propcrty, such as section modulus or cross section area. DESIGN WALL THICKNESS. HSS wall th ickness assumed in the determination of sec ti on propeI1i es.
DIAGONAL BRACING. Inclined structural member canyin g prima ril y axial force in a braced frame. DIAGONAL STIFFENE R. Web s tiffener at column panel zone oriented diagonally 10 [he ~anges, on one or both s ides of the web. DIAPHRAGM PLATE. Plate possess ing in·plane shear sti ffness and strength, lIsed to transfer forces 10 the suppol1ing elements. DIAPHRAGM. Roof. floor OJ" olher mem brane or bracing system th at transfers in -plane forces [Q the lateral force resi sting system . DIRECT ANALYSIS METHOD. Design method for stability that captures the effects or residual stresses and initi al out-of-plumbness or frames by reduci ng stiffness a nd appl ying flotional londs ill a second-o rder analysis.
members.
COPE . Cutou t made in a structura l member to remove ,\ nmlge and co nform to the sha pe oj' an intersect ing member.
COVER PLATE. Plate welded or bolted to the flange of a member to increase cross-sectional area, section m odulus or moment of inertia.
DIRECT BOND INTERACTION. Mechan ism by which force is transferred between stee l and concrete in a com posilc seclion by bo nd stress. DISTORTIONAL FAILURE. Limit state 'of an HSS truss connect ion based on distortion of a rectangular HSS c hord member into a rhomboidal shape. DISTORTIONAL STIFFNESS. Oul·of·plane flexural stiffness of web.
National Structural Code
o·r tl1 8 P ll ilippines G!II Edition Volume 1
:) ~lO
CHAPTUi [) . Steel and Metals
DOUBLE CURVATURE. Deformed shape of a beam with one or more inflection points within the span. DOUBLE-CONCENTRATED FORCES. Two equal and opposite forces that form a couple on the same side or the loaded member.
DOUBLER. Plate added to, and parallel with, a beam or column web 10 increase resistllllce to concentrated forces.
EYEBAH. Pin-connected tcnsion rneml)(:r of uniform thickncss, with forged or thermally cut head of greater width than the body, propo!1ioncd to provide pproximately equal strength in the head and body. FACTORED LOAD, Product of a load factor and the nomina! load . FASTENER. Generic term for bolts. rivets. nr other cOllnecting devices.
IHUFT. Lateral deflection of' structure. EFFECTIVE LENGTH FACTOR, K. Ratio between the effective length and the unbraccd length of the member. EFFECTIVE LENGTH. Length of an otherwise identical column with the samc strcngth when analyzed with pinned end conditions.
EFFECTIVE NET AnEA. Net area modified to account for the effect of shear lag.
FATIGUE. Limit state of crack initiation and growth resulting fro III repeated application of live loads. FA YING SURFACE. Contact surface of cOllnectioil elements transmitting a shear forcc . FILLED COMPOSITE COLUMN. Composite colulll;] consisting of a shell of HSS or stee! pipe lJ!led with SLJ:uctural concrete. FILLER METAL. Metal or alloy
10 be added
in making
a welded joint. EFFECTIVE SECTION MODULUS. Section modulus reduced to account for buckling of slender compression clements.
FILLER. Plate used component.
to
build lip the thickness of
O]]C
FILLET WELD REINFORCEMENT. Fillet weld ,;
EFFECTIVE WIDTH. Reduced width of a plate or slab with an assumed uniform stress distribution which produces the same effect on the behavior of a structural member as the actual plate or slab width with its nonuniform stress distribution .
FILLET WELD. Weld of generally triangular CI""; ,·. section made between intersecting surfaces of clcments.
ELASTIC ANALYSIS. Structural analysis based on the assumption that the structure rcturns to its original geometry 011 removal of the load.
FIRST-ORDEH ANALYSIS. Structnral analysis in which equilibrium conditions arc formulated on the: undcformed structure; second-order effects arc neglected.
ENCASED COMPOSITE COLUMN. Composite column consisting of a structural concrete column and one or more embedded steel shapes.
FITTED BEARING STIFFENER. Stiffener used at ,. support or concentrated load that fits tightly against Oi'" or both flanges of a beam so as to transmit load throul'.! 1 bearing.
END PANEL. Web panel with an adjacent panel on one side only. END RETURN. Length of fillet weld that continues
added to groove welds.
FLARE BEVEL GROOVE WELD. Weld in a groove formed by a member with a curved surface in contact \\ a planar member.
around a corner in the same plane.
ENGINEER-OF-RECORD. Licensed professional responsible for sealing the contract documents . EXPANSION ROCKER. SUppOit with curved surface on which a member bears that can lilt to accommodate expansion.
FLARE V-GROOVE WELD. Weld in a groove formed by two members with curved surfaces. FLAT '''IDTH. minus twice the knowledge of the taken as the total thickness.
Nominal width of rectangular ll ~ ,' ~ ' outside corner radius. In ab~ (" corner radius, the flat width Iii: ,} b(; section width minus three times the
EXPANSION ROLLER. Round steel bar on which a member bears that can roll to accommodate expansion. j~ssociation
of Structural Engineers of the Philippines
C H APTE:~~ ~
FLEXURAL BUC KLINC. Buckling mode in which
mode
ill
whi ch
II
BUCKLING.
com pression
mem ber
Buck ling
S?!
GRA VfTY LOAD. Load, such as that produced by dr.:aJ and live loads, acti ng in the downwa rd direction .
(om pn:ssion memher de flects lalcrn ll y without twist or change in LTOSS ~sct..' t j() nal shape. il
FLEXURAL-TOHSIONAL
. Stee l and Metals
GUlP (OF HOLT). Th ickne~s of materia l th rough whic h a bol! passes.
bends and
(wists simultaneo usly wi thout change ill cross-sectional shape.
ROOVE WELD. Weld ill a groove between t:o lln cc lioll clements. Sec also AWS D 1.1. .
FORCE. Hcs ult ant of di stribution of stress over a presc ribed "rca.
GUSSET PLATE. Plate clement co nnecti ng tru s:\ members or
FORMED SECTION. See cold- fo rmed stee l structural
HORIZONTAL SHEAR. Force at the in terfa('(' between steel and concrete surfaces in
member.
FORM ED STEEL DECK. In co mposite construc ti o n. sleel col d formed inlo a decking profile used as a pennanenl concrete form. F ULLY RESTRAINED MOMENT CONN E CTlON_ Connection capable of Iransfen'i ng moment with negligi bl e rot ati on betwee n connected members.
GAGE. Transve rse ce nter-Io-center spacing of fasteners. GAP CONNECTION. HSS truss connection with a gap or space on (he chord face be tween intersecting branch
HSS. Squa re, rectangular or round hollow stnlctural steel section produced in acco rdance wi th a pipe or tubing product specificali on. User Now: A pipe can be designed using the same design rules for round HSS sections as long as · it confonns to ASTM A53 Class B and the appropriate parameters are used in the design. INELASTIC ANALYSIS . Structural anal ysis th aI takes
members.
int o acco un t inelastic material beha vior, incl uding plastic analys is.
GENERAL COLLAPS E. Li mi l stale of cho rd plaslificalion o f opposi ng sides of a round HSS chord membe r at a cross-co nnection.
IN-PLANE INSTABILITY. Lim iL state of a beamcolumn bem about its major axis wh il e lateral buck li ng or lateral-torsional buckling is prevented by lateral bracing.
G EOMETRI C AXIS. Axi s parallel to web. flange or angle leg.
it
GIRDER FILLER. NalTow piece of s heet steel used as a fi ll between th e edge o f" a deck sheet and th e flange of a gi rd er in a composite floo r system co nstru cted using a formed steel deck.
INSTAIllLlTY. Limit state reached in the loading of sll1Jctural component. fra me or structure in whic h a slight disturbance in the loads or geometry product..... large displacements. JOINT ECCENTRICITY. For HSS tru ss co nn ec tion. perpendicular distan ce from chord member ce nt er oj' gravity 10 infersection of branch member work poi nts.
GIRDER. Sec Beam.
GIRT. Horizo nt al st llH;tura l member th at su pport s wall p:lIlels and is prim aril y subjected to bending under horizon tal loads, such as wind load. GOUG E. Relatively smooth surface groove or cavi ly n:.sulting from plasti c dcfoflllfltion or remo va l of material. GRA VITY AXIS. Axis through the cent er of gravity of a member along its le ngth. GRAVITY FRAME. Poni on of the framing system not included in the la ternl load resisting system.
Joi nt t. Area wh ere two or more ends, surfaces, or edges arc aft ached. Calegorized by type of fastener or we ld used and method of force transfer. K- CONNECTION. !-ISS connectio n in which forrt'..... in bnmch members or cO llnecting elemen ts tnllls vcrsc 10 the ma in member [Ire primarily cquilibriated by fOref!, in other branch members or connecting elemenls 011 the same side of the main member. LA C ING. Plate, angle or other steel shape, in " lattice confi guration, th at connects two steel sil nlh::; together.
1h
National Structural Code of the Phili ppi nes 6 Edition Volume 1
LAP JOINT. Juint between two ovcrl
LENGTH EFFECTS. Considermion of the redu ctio!] in streng th of a member based on its unbraccd leng th. LIMIT STATE. Condilion in which a Sll'llclurc or component brcolllc~ unfit for service <.IIld is judged ei ther to be no longe;' usefu l for it s intended fUJl cti on (servi ceability limit slate) or to have reac hed its ultim
LOAD EFFECT. Perces. Stresses and ucfonnat iolls produ ced in a stru ctu ral componenl by
LOCAL C IHPPLI NG. Lillli t SW l l' 0 1' 10(.";11 ra il ul"llofweb plat e in the immed iat e vicinit y of a n)lll"C nl r .. l l~d load or rcm:linn. LOCAL YIELDING. Yi~ l ding that occurs in;1 local arC'l or un element. Ull'D ( L()AD AND R ESISTANCE DESIGN ). Method of propol1iu ~l illg
FACTOR struct ural
cOlllponent s sllch that the design slI ':-'i l~th l~l ual s or cxcccJ s the required strength of the component under the acti o n of the LRFD IOtid cOl nbill tlt iol1s. LRFD LOAD COM nINA TlON. Load com binali o n in this code inlcnded for strength dcsign (load amI resista nce fclclOr design) . MAIN MEMBER. For HSS connect io ns. cho rd member, column or other H SS membcr 10 whidl bmnch members or other connecting clements arc allachcd.
MECHANISM. Structuntl sys tc m that includes a sufficient number of real hin ges, plastic iii l1):,cs or both, so as to be abl e 10 articulate ill 011(' in IliO]"C' rigid body modes. ]'VIILL SCALE. Ox ide surface coating on sted i"m mc (] by tile hot ro!ling process. MILLED SURFACE. S urface [hal has beell Iln(:h:ll(~d nm by a mechalli c,ill y gu idcd too l to it !;,!l, :;l\1oolh condi tion, CONNECTION. MOMENT momcnt tra nsm it s bendi ng
Conllection that ( ('Ilncctcd
bCI weell
members. MOMENT FRAME. Framing 'ysle m Ii;;" .lro" d,.; resistance to lateral loads and provides sltlbilipf' 10 the structural system. primarily by shear i!nd ' ;, '::,: ..:. Gf
the framing mcmbers and the ir connection:. Ihe appli ed load,.
NET AREA. Gro5s area reduccd material.
to aCCOIE1< ~o :
LOAD FACTOR Fac IoI' {hilt acco unt s for dev iations o f the nominal load from the actu al load. for uncertainti es in the an al ys is thal l ransfo rllls the 10,1d! ill w 11 load effect and for the probabilit y that more tha n olle ex tre me load will occur simultaneous ly.
or twist indcpendentl y o f 0:]; I adjaccllt brace po ints (sec relati ve brace),
LOCAL H1~NDING. Limit stale of la rge deformation o f a O:lI1gc under a concentrated te nsile force.
dimension , as in Ihe tahles
LOCAL BUC KLING. Limil Slale of buckling of a compression element within a cross section.
this code.
NODAL
BRACE.
Brace
thaI
1'1\.··.';.:,1:;
Illo vc m c n t
;,:
,\'C~:
I •• ;' .
iii..'J _: .,i
NOM INAL DI !'VIENSION. Designated or llieordic;,;
or
section pi ,.:--:.
NOMINAL LOAD. Magniwtl e of Ihe 1o,, '!
Association of S tructural Ellginc(;)["s of the Philippines
NOMINAL lUll H E IGHT. I-ki gh t of I' ".,ned steel deck mcaslII'cd from the underside of th e lowest point to (he top o f th e hi ghest point.
PIPE. Scc HSS PITCH .
Longitu din al ccn\ (:I'-((H.'c ntcr spaci ng oj' CClltcr-IO-CClltcr spac ing or bol l th reads along axis of bolt. f~l stclle rs.
NOM INA L STRE 'GTH. St rength of a stru cture or com ponent (wi tho ut th e l:csisl;IIlCC f
accordance wi th this SpecificHtion. NONCOMPAcr SECnO N. Section that can dcvelop th e yield stress in it s co mpression clemen ts before loca l bUl'kling occurs, but can not develop a rotati on capacity of' three.
NO NDESTR UCTIV E procedure wherein 110
TESTING. Ins pection tnaterial IS destroyed and
PLASTI C ANALYSIS. StrllcllIral ana lysi s based on lhe assumptio n of rig id-plaslic behav ior, in olhe r words. tilat equilibrium is sm isfi ed throughout the slrtlcturc and the stress is at or be lm'>' the yield stress. PLASTI C HINGE. Yielded I.Oll e th at form s in n structural member \vhcn th e plasti c moment is at tained. The member is assumed to rot ate further as i f hinged, exccpl that such rotat ion is restrained by the phlsti(' mOlllc-nl ,
illlcgrily of the material or compo nent is not alTcctod. NOTCH TOUGHNESS. Energy absorbed at a specified
PLASTI.C 1\tIOMENT. Theoretical rcsisting momen t de veloped within a fully yielded cross section.
temperature as measured i n the Charpy V -Notch lesc
NOTIONAL LOAD. Virin a) load applied in a " roetura) ;mal ys is 10 accotlnt for dcswbili zi ng cJTccts Ihill are not otherwise accollllled for in the design pro visions. OUT-OJi'-PLANE IIlJCKLING. Lim it state of a its Jll (~io r axis while hea m-col um n belll about lateral buckling or lateral -torsional buckling is not prevent ed by laleral bracing.
PLASTIC STRESS DISTHIB UTION METHOD. Method for determi ning the st resses ill a composite member assumin g Ihat the stee l secl ion and the concrete in the cross section arc fu lly plilstic.
PLASTIFICATION. 111 an HSS con ne cti on, limit stale bHsed 011 an oU I-of-pla ne ncxural yie ld line mechanism in the chord
OVERLAP CONNECTION. HSS lru ss coll ileeti oll in wh ich imersecting imUlch members overl ap.
PANEL ZONE. Web arc;] or bemll-IO-colull1l1 connection delineated by the extension of bea m and column fhlll gcs through the connecti on, transmitting moment through a shenr pane l. PAHTIAL-JOINT-PENETRATION GROOVE WELD (PJ]». Groove weld in which the penetrati o n is intentionall y less than the co mpl ete thickness of the connected clement. PARTIALLY RESTRAINED MOMENT CONNECTION. Con necti on capable of transferrin g moment with rotati on between connected members that is not negli gib le. PERCENT ELONGATION. Measure of d uctilil y, determ ined in a tensil e test ns the max imum elongation () f the gage length d ivi ded by the original gage length. PERMANENT LOAD. Load in which variations over time arc rare or of small magnitude.. All other loads are variable loads.
PLUG WELD. We ld m.ute in a circular hol e in one element of ajoint fusing that clement to an othe r element. PONDING. Retention of water d ue solely to th e deflecti on of Oat roof framing. POST-B UCKL!. G STRENGTH. Load o r fo rce that can be ca rried by an element, member, or frame after initial buckling has occ urred . PRETENSION E D JOINT. JOilll wilh high-strength bolts lightened to the specified minimum pretension. PROPERLY DEVELOPED. Reinforcing bars detClilcd to yield in a ducti le manner before crushing of the concrete occurs. Bars meeting the provisions of ACJ 3 18 insofar as deve lopmclll lenglh, s pacing and cover shall be dee med to be pro perl y developed. PRYfNG ACTION. Amplifi cation of the te nsion force in a bo lr caused by leverage between the poin t of applied load, the bolt and the reliction of the connected elemcm:-i. P UN CHING LOAD. Compooellt of brallch member force perpendicular to a choro.
Nationa l Structural Cod e of th e Philipplnes 6
th
Edition Vol ume '1
PlJRLIN. Horizontal structural member that supports roof deck and is primarily subjected to bending under vertical loads such as snow. wind or dead loads. ~(5 EFFECT. Effect of loads act! ng on the deflected shape of a member between joints or nodes,
P
P -A EFFECT. Effecl of loads acting on the displaced location of joints or nodes in a structure. In tiered building structures, this is the effect of loads acting 011 the laterally displaced location of floors and roofs.
QUALITY ASSURANCE. System of shop and field activities and controls implemented by the owner or his/her designated representative to provide confidence to the owner and the building authority that quality requirements arc implemented.
ROTATION
CAPACITY.
Incremental
angular
rotation that a given shape can accept PrJor to excessive load shedding, defined as the ratio of the inchl:>tic rotation attained to the idealized clastic rotation at first yield.
RUPTURE STRENGTH. In a connection, strength limited by tension or shear rupture.
SAFETY
FACTOR. Factor that accounts for deviations of the actual strength from the nominal strength, deviations of the aClUal load from the nominal load, uncertainties in the analysis that transforms the load into a load effect, and for the manner and consequences of failure, SECOND,ORDER ANALYSIS. Structural analysis in
QUALITY CONTROL. System of shop and field controls implemented by the fabricator and ereclor to ensure that contract and company fabrication and erection requirements are mel.
RATIONAL ENGINEERING ANALYSIS.
Analysis
based on theory that is appropriate for the situation, relevant test data if available, and sound engineering judgment.
REENTRANT. In a cope or weld access hole, a cut at an abrupt change in direction in which the exposed surface is concave.
which equilibrium conditions are formulated on deformed structure; second-order effects (both and P-Il, unless specified otherwise) are included,
the p-()
SECOND,ORDER EFFECT. Effect of loads acting on the deformed configuration of a structure; includes P-O effect and P-/1 effect. SEISMIC RESPONSE MODIFICATION COEFFICIENT. Factor that reduces seismic load effects to strength level.
SERVICE LOAD COMBINATION. Load combination under which serviceability limit states are evaluated.
RELATIVE BRACE. Brace that controls the relative movement of two adjacent brace points along the length of a beam or column or the relative lateral displacemcnt of two stories in a frame (sec nodal brace).
SERVICE LOAD. Load under which serviceability limit states are evaluated.
SERVICEABILITY REQUIRED STRENGTH. Forces,
stresses
and
deformations acting on thc structural component, determined by either structural analysis, for the LRFD or AS]) load combinations, as appropriate, or as specified by this Specification or Standard.
LIMIT
STATE.
Limiting
condition affecting the ability of a structure (0 preserve its appearance, maintainability, durability or the comfort of its occupants or fUllction of machinery, under normal usage.
SHEAR BUCKLING. Buckling mode in which a RESISTANCE FACTOR. Factor that accounts for unavoidable deviations of the nominal strength from the actual strength and for the manner and consequences of failure.
REVERSE CURV ATURE. See double curvature
plate clement, such as the web of a beam, deforms under pure shear applied ill the planc of the plate.
SHEAR CONNECTOR. Headed stud, channel. plate or other shape welded to a steel membcr and cmbedded in concrete of a composite member to transmit shear forces at the interface between the two materials.
ROOT OF JOINT. Ponion of a joint to bc welded where the members are closest to each other.
SHEAR CONNECTOR STImNGTH. Limit state of reaching the strength of a shear connector, as governed by the connector bearing against the concrete in the slab or by the tensile strength of the connector.
Association of StructuI'81 Engineel's of the Philippines
~--- -
CHAPTER 5 ~ Sleel and f",./etals
SHEAR 10 shc
I~UPTURE.
5-25
Limit state of rupt ure (fracture) due
SLlp·CRITICAL CO NECTION. Boiled conneclion
SHEAI{ \VALL. \Vall that provide:) resis tan ce to lateral loads in the plan e of th e wall and provid es st ab ility for the SlJllClU ru l systc:m. SHEAR YIELDING. Yielding that occurs due to shear.
SHEAR
YIELDING (PUNCHING). In an HSS connectioll. limit state. based on out-of-plane shear strength of the chord wi.tll to which branch ITlcmbe rs are 'I tlHelled.
des igned to resist movemen t hy rriction on (he raying surface of the conn ection under th e clamping for ces of the bolts. SLOT "VELD. Weld made in an elongated hole fusing an e lcmel1l 10 another Cle ll1 CIll.
SNUG·TIGlfTENED Joint with JOINT. lilc connected plies in firm contact as specified in Section 510. SPECIFIED
SHEET STEEL. In a comp osite floor system, st eel used for closure pl
SIDESWA Y
IlUCKLING. Limil sla lc o f lalcra] buckling of the tension flange opposite (he location of a co nccn tr::ncd compress io n force.
SIDEWALL CRIPPLING. Limil slalc of web crippling 01" the si dewall s of i.I chord member at a HSS truss connection.
MINIMUM
TENSIL~;
Lower limit of tensil e strength Illaterial as defin ed by ASTM.
STRENGTH. for a
specified
SPECIFIIW MINIMUM YIELD STRESS. Lower limil oj" yicl d sii·css speciried fo r a material as defi ned by ASTM. SPLICE. Co nnec ti o n between two structura l clements joined at their ends (0 rorm 11 single. longer elemenl . STABILITY. Condition re ached in lhc loading of ..1 structural co mponent, frame or structure in which a slight di sturbance in fhc load s or geometry does !lot produce large d ispl;'lcemcnts.
SIDEWALL
CRUSHING. Limil Siaic based o n bearing strength of chord member sidewall ill HSS truss cOllnect i oJl .
STIFFENED ELEMENT. Flal compression elemenl with adjoi ning out -o f-plane clements along both edges parallcllo the dirct:tion of loading.
SIMPLE CONNECTION. Connection thm lnmsmi ts neg l igible hending moment between connected lllcm bcrs.
STIFFENER. StruclU ral element, usually an angle or
SINGLE-CONCENTRATED
FORCE. Tensi le or compressive force applied normal to the fl ange of a member.
STIFFNESS. Rcsfslancc lO deformation of a member o r structure. measured by the ratio of the appli ed force (or moment) to the. corresponding displacement (or rotation).
SINGLE CURVATURE. Deformed shape of a beam with 110 inflection point within the spall.
STRAIN COMPATIIlILITY
plaLc,
f
,!
SLENDER·ELEMENT SECTION. Cross secl ion possessing plate components of suffi cien t
METHOD. Method for determining the stresses in a compos it e member considering ihc s tress~st raiJl relalionships of each material and its location with respect to the neutral axis of the cross sectio n.
slenderness such that local buckling in the elasti c range will OCC llr.
STRENGTH
S LIP. In a boiled connection, limit stale of relative motion of connected pans prior to the attainment of the available strcngl h or the conneclioll.
LIMIT STATE. Limiling condilion affecting the safety of the stfllc ture, in which th e ult im ate load-carryi ng capaci ty is reached .
STRESS. Force per unit area cau sed by ax ial force, moment, shear or tors-ioll .
l
National Structura l Code of 111(-J Ptlili ppine s 6 f'. Edition Volume 1
.,
..
STHESS
CONCENTItATION.
I.ocalized
st ress
considcrnb ly higher than
TIE PLATE. Plate clelllcllI lIscd to join two p~l ra1iel l;omponcllts of .1 huilt -uJ> (":ol ulI)l1 . girder or strut ri gidly connected 10 the parallel l.:ompullcn ts and (k ~ iglle d to transmit shear hCl\vct!1l them.
STnONG AXIS. Major principal wlIroidal axis or a cross sectiull.
TOE OF FILLET. JUlll'lion or a rillel wel d race and base mC la !. TangclH point uf il rolled secti on fllle!.
STRUCTURAL ANALYSIS. DClerminalioo or 10ild effects on members and COllllcc lions bmicd on principles
TORSIONAL HHAC1NG. Br;lci ng resis ti ng twist of ·i~· beam or column.
of'sll1IclUral mechanics.
STRUCTunAL COMPONENT. Member. w nneclOr, connecting element or assemblage. STRUCTURAL STEEL. SICcl clemeols as de lined in Seclion 2.1 or Ihe AISC Code of SIaooard Pracl ice ror Steel Buildings and Bridges. STRUCTURAL SYSTEM. An assemblage of load· can'ying components thaI arc joined together (0 provide imcracliol1 or interdependence.
T·CONNECTION.
HSS
conneclion in
TORSIONAL BUCKLING. Buckling mode ill ,',·h ieh a compression membe r twi sts about its :-.11<'.,:- c.. : nt cr
TORSIONAL YIELI>ING . Yielding Ihal Occ urs due torsion.
10
TRANSVEnSE REINFORCEMENT. Slcel reinforcement in the forlll or closee! ties or welded wire fabric providing confinement for (he concrete. surrounding the steel shape core in an encased concrete composite column .
wh ich Ihe
bmnch member or connecting element is pcrpcndi cu J,u' to the main member and in which forces lransverse to the
TRANSVERSE STIFFENER. Web sl iffenCl' (,riented perpendicular to the flange s, att ac hed to the web.
main member arc primaJily equilibriatcd by shear in th e
main member.
TUBING. Sec HS S.
TENSILE RUPTURE. Lim il Slale or ruplllre (rraclure) due to tensioll.
TURN·OF· NUT METHOD. Procedure whereby rhe specified prelens ion in high-s trength bolts is controlled by rotating the fastener componellt a predetermined amount aher the bolt has been silug lightened.
TENSILE STnEWGTH (OF MATERIAL). Maximum tensi le stress lhat ~I material is capablc of sustaining as defined by ASTM. TENSILE STRENGTH (OF MEMBER). Maximum tension force th at a member is capablc of sustaining. TENSILE YIELDING, Yielding Ihal occurs clue te nsio n.
10
TENSION AND SHEAR IWPTUn E. In a bol'l, lim il s tal e o r rupture (rractu rc) due lO simultaneous tcns ion and shear force.
UNDRACED LENGTH. Distance between br:H:ed points or a membcr, mCilsu rcd between the ce nters o~ ~:l . : ·.i:.; >l[ the bracing members. UNEVEN LOAD D1STRIIlUTION. In "" lISS connection, cond ition in which th e In:.;! :'; distriblll cd through the cross secti on nf" ("olHlfTf n i clemel1ls in a manner thai can be rC
TENSION FIELD ACTION. Behil vior of a panel under shear in which diagona l tensile forces develop in the web and compressive rorces devclop ill the transvcrse stiffeners in a manner similar to a Pratt truss. THERMALLY CUT, elll wilh gas, plasma or laser,
UNSTIFFI~NED ELEI\'IENT. Flat COllljl i\·;'Wlil I:kmc.n! with an adjoining oUI-of-plane elemeJlt .;;.: : parallel to the directi oll of loadin g. <
VARIABLE LOAD. Load nOI class iG,:.! loael,
Associati on of Stru ctural Engineers of the Philippines
VEHTlCAL BHACING SYSTEM. SYSlCIll of shc"r walls. hraced frallles or bOlh. extending through one or lI10re HOOfS of'l building.
WEAK AXIS.
M illOI'
principal cCHtroidal axis of' a crOss:
sect ion .
YIELDING
(PLASTI C
WEATHEnING STEEL. High-strength, low-alloy steel L
paint coaling. WEn BUCKLING . Limit Slat e of lateral instabi lit y of a web.
WED COMPHESSION DUCKLING. Limil S1ale of
ollt-or-plane compression buckling of the web due concentrated compression force.
10
a
WEB SIJ)ESWA Y BUCKLING. Limil slale of lale ral
buckling of th e tension fl ange opposite the location of a concentrated compression force.
WELD METAL. Portion of a fusion weld th at has been completel y melted during welding . Weld metal has elements of filler metal and base metal melied in the weld themlal cycle.
WELD ROOT. See rOOI of joi nt. Y-CONNECTION.
HSS conneclion in which Ihe or connecting e lement is not perpendicular 10 the main member and in which forces transverse to the main member arc primari ly equilibrialcd by shear in the main member.
branch
Yielding ilS
the
YIELDING (YIELD MOMENT). Yielding allhe extreme fiber on the gross sec tion of a member when the bending m O llll'!lI rcaches Ihe yiclc.l moment.
:hat, with suitable precautions, can be used in normal atmospheric exposures (not marine) without protective
MOMENT).
throughout Iht cross section of it member bending moment reaches lhe plasti c moment.
member
YIELD MOMENT. In a member subjecled 10 bending, the mom ent at whi ch the ex treme outer fiber first attains the yield stress. YlELD POINT. First stress in a material at which an increase in strain occu rs without an increase in sHess as defined by ASTM. YIELD STRENGTH. Stress at which a material exhibits a speci fied limiting deviation front the proportio nalit y of stress to s lr~lill as defin ed by ASTM. YIELD STRESS. Ge neric lerlll 10 den ole eilher yield point or yield strength, as appropriate for th e materiaJ. YIELDING. Limit state o f in elastic deformati on thal
OCcurs after the yield stress is rcached.
Naliona l S iruciural Code of Ihe Philippines 6'" Edilion Volume 1
!; 2H
CHAP rE n
~J
'
Steel ane! Me tals
8.J.!}QTION,{$Ql : ; .. GENERAt "PROV'isIONS SO1.1 Sco pe Th is section slatcs the scope or the Specifica tio n, sll flli llari zcs rcfefcllccd spccificalioll, code. and standiu'd documents, and providl!s rcqllircmcnls for materials and contract dO<.:V lllcnl s, Th e secli on is orgal1i ~c d as follows:
501. 1 501.2 SOl.) 501.4
Scope Hcfereneed Specifications. Codes ilnd Sttlnd:lrds Material Slfu<.:lufal Design Drawings and Spccific~H i ons
The User NOlcs interspersed Ihroughoul arc not pan o r the Spcci fi c.: atioll,
Buildings (NSCP Chapter .
User Note: User notes arc intended to provide concise and practical gu idance in the application of the provisions. Thi s Specificatio n sets fort h criteri a for the des ign, fabricati on, and ercc ti on of structural steel buildings and oth er st niClUreS, where oth er structu res arc de fined as those stnJcrures designed. fabricated, and crectcd in a manner similar to buildings. wiLh building-l ike vert ic;.!1 and lateral load resi~tin g element s, Where condi tions are not covered by the Specificmion. designs are permitted to be based on tes ts or analysis. subject 10 the approval of the authority havi ng jurisdiction. Altematc methods of analys is and design shall be pcmliucd, provided such alternate methods or criteria arc acceptab le 10 the authority havi ng jurisdiction, User Note: For the design of structural members, other Ihan holl ow structu ral seclions (HSS). lhal arc cold formed to shapes, with elements not more than 25 mm in thickness, the pro visions in the AISI North American Specifi calio n for Ihe Design of Co ld- Formed Sleel Structural Members are recommended, 5 01 .1.1 Lo w-Seis m ic Appli ca ti ons When the seismic respo nse modifi cation coeffi cient. R, (as specified in this code) is taken eqlwl to or less than 3, the design, fabrica tion. and erection of stfllcllIr
50 1.1.2
Hi g h ~Sc i s mi c
Applica ti olls Whe n the scismic response modi fi catio n coefficicnt, R, (as specified in this code) is taken greater than 3, the design, fabrication and erec tion of struc tural-steel-framed build ings and other stnlctures shall comply wit h Ihe requirements in the Seismic Pro visions for Stl1lctural Steel
Buildillg
Code
Requir('metlls
f or
St'-Ul'llll"a/ COllcre te (llId CUllltII!'lIrary
AC I 3 JSM-08 M errie /Ju i/dilll{ Cude /?('qllirem
Am eri ca n Institute of S teel COII!-.Irll ctio n, Inc. (AlSC)
AISC 3 03-05 Code of SUlIIdard Prac tice for Sleel Bui/ding!; and Bridges ANS I/ AISC
34 1·0 5
Se ismic
PreJl' isions
Jor
S/rllcl lira / S teel Bu i l ding!;
ANSIIA ISCN690-1994(R2004)
Specification Jor t"e
Design. Fabricatioll and £rec rirJlJ of Stet'! Safefr-Rl'faled
Structures lor Nuclear Facililies. includ ing Su pplement No. 2 AN S I/AISC N690 L-03 Load and Resistwlce FaclOr Design Sped[ica lioll fo r Steel Safety· !?"lated StfU Clllres fo r Nuclear Facilities Am erican Society of C ivi l E ngin ee rs (ASCE)
SEIIASCE 7·02 M inimum Design LO(l(/s for l1uifdin,p', (llld Other SII"f-l(.'llIres ASCElSFPE ',l9-99 SUIII./Ufu' ClI/cu/llIioll Methm}sfl)I' Structural Fire PrcJl('clicm Am er ican Society or Mecha ni cal Engineers (ASI\'l E)
ASME 13 1 8.2,6~96 Fasteners /0 1' U.W~ ill '\'(I'UN ii:,-'Applications ASM E B46.1-95 SlIrJacc Textllre. SlItiace ROllgh"" H'avil1ess. alld Lay
Association of Slructural Engineers of" the Philippines
•
CHAP1TH 5· SIGel and Melals
5·(!9
ASTM Intcrnlltiolllll (ASTM)
A500-03'1 Standard ~iJl'cijic(J/ioll fiJI' Cold·Fm11lt·d We/tit'll (Illd Scumle.,",," Carbull S(l'('1 Structural Tubing ill f(ound,"
A6IA6M·()4a
SWI/dard .~i}ecijic{/f;oll for Cit-neml !?('l!u;rl'lIIel1/s jiJI" Nul/cd SlruC:lllml Sleel iJars. 1'/(11(,,\' ,
alld Shape.,"
ShaJ)e,\', (llId Shc('f Pi/inK
ASOJ-OJ Slandard Sj)('cUiclIliol/ for Jim· Formed Hle /ded (IIu1 Sl.'lImlt'sJ GII"boll S(c'cl Stn,(.'tumJ Tubin!:
A36/A36M-04
SWlldard Sped/ieaf;oll Jor
Corium
AS02 -03 SI(11I(I(lI"(/ Specific:alioll [or Sleet Stnn:rural
StrU('lura! Steel
i?ivefs
AS3/ASJM-02 ~'((mdard Specijicalioll for Pipe. Sled. Black lIlId HOI- Dipped, Zillc-COlunJ, Welded and S(,(lIl1les:l'
A5 14/A5 14M·OOa Sumc/o,-t/ Sju'£"ijiwtioll fodligh·Yieid Strength, QUlmclwd lUul Tempered Alloy Steel PfaH'. Suitable Jor Welding
A 193/A I 93M-04a SfUlu/urd ~i}ecificatioll Jor Alloy·Steel lind Slainless Stcel BO/lillg MlIIerials Jor High ·, Tt.~tllper{1 lure Sen/ice A I 94/A J94M-04 Sllmdard ~i)ec~{icari()11 Jor Carbon and' Alloy Steel NUls J(JlBolls For High Prl'ssure o r Higli''/'l1mperol/(u: S(,I"I'i('(', or 130th
A216/A2 J 6M·93(2003) Slam/ard SpaijiclIliofl for Steel Castings, Carboll, Suitable for FIlSioll Welding, for High Tempemtul'r! Service A242/A242M-04 Standard Specijicafiol1 for HiKh-Strength wlv-Alloy Structural Steel
A283/ A283M-03StGlldard Specificatioll for Low and Illtermediare Tef/sile Strength Carbon Sleel Plale.'i A307 -03 Standortl Specification for Carbon Gild Sluds, 60,000 PSI Tellsile Slrellgl"
St(~el
Boils
A325-04 Standard ,~i)ecificar;oIlJor SrrllclUral BO/IS, Steel. /-leaf Treated. 1201105 ksi Minimum Tensile Slrength A325M-04 Standard SpecijiclJ.Iiol! for Bolts for SlruclUrai Steel Joints (Metric)
High-Strength
A354-03a Stalldard Specificatioll for Quellched alld Tempered Alloy Steel BolES, Studs, and Other Externally Threaded Fasfell ers A370-03a Standard Test Methods alld Definitions Jor Mechanical Testing o/Steel Products
A449-04 Stamlord SpecificationJor Quellched alld Tempered SteeiBolts and Sluds A490-04 Standard Specification for Hem-Treated Sleel Structural BoilS, J50 hi Millimum Tel/ sile Strength A490M-04 Slandard Specification forliigh-Slrengl" Sleel BoIlS, Classes 10.9 alld 10.9.3, for Slruclllml Sleel Joillls (Metric)
AS29/A529M-04 Stanc/ard Specification for High -Strength Carbon-Mangallese Steet ofS'truclUral Qua/ity A563-04 Standard Specification for Carbc)1I and Alloy Steel NUls A563M-03 S'umdard Spec(/icarioll for Carbon and Alloy Sleet NUIS I Metric] A568! A568M-03 Sl£IlIdard Specificarion for Steel, Sheer, Carbon. and High-Strength. Low-Alloy, HOI-Rolled alld Cold-Rolled, Gelleral Requirements for
A572!A572M-04 Slalidard Specljicolioll for Hi ghStrengfl! Low-A 1I0y Columbium- Vanadium StrUCTUral Steel A5881A588M-04S(Qndard Specificalioll S trength Low-Alloy Sfrllctural
far
High-
Steel wilh 345 MPa Miliimuf1I Yield Poinl 10 100 mill Thick A606-04 Standard Specification Jor Steel, Sheet and Slrip, High-Strength, Low-Alloy, fl OE-Roiled and ColdRolled, wirh improved ATmospheric Corrosion Resistance A618/A618M-04 SWlldard Specificalion for HOI-Fomlfd Welded and Seamless High -StrengTh Low·Alloy Struclural TII.bing A673/A673M-04 SIandard Specification for Sampling Procedurefor Impact Teslillg ofStruclllrtll Steel A668/A668M-04 Standard Specificalioll for Sleet Forg illgs, Carbon and Alloy, for Genera/Industrial Use A709/A709M-04 Slandard Specificalioll for Carboll and liigh·Strength Low-Alloy Stmcrural Steel Shapes. Plates, and Bars and Quenched-and- Temp ered Alloy Structural Steel Plates for Bridges
tl1
National Structural Code of tl18 PlliJippines 6 Edition Volume 1
•
!5-30
CHAf)TU~~)
. Steel and Melals
A 751-0 J SWI/dard Test M('[hods, Pracliu's, and Tf/rmil1o{ogyfor Chemical Alwlysis of Steel Products
American Welding Society (A WS) AWS Dl. JlD I, IM-20()4 S!mClllral We/din~ Cor/e·"Steei
A847-{}{}a (2001) S'lwulord 5j)('ciji('(ltiO!l for ('o/d-Fom1('d We/dnl dlld Seam/e.l's 1-1I"!;h-Slrellgth, Low-Allo), StmcfUrof 'jilbi'l~ with Il1Ipr(JI'ed AlfllO.spheric CO!Tosion Resisl(lIJCe
Fo/' Shielded
A852/A852M-01 Standard ,~jJe(.'lfic(Jtion for Quellched and Tempered Low-Alloy Stl'llctum/ Steel Plate wiTh 485 MPa
AWS AS.5-96 SpeC/jicalioll for Low-Alloy E!eumdesfor Shielded Mew/ Arc Wel
A WS A5, 1-2(X)4 .~j}('c(/ic(l/ioll for Carbo/l STeel Efecfrodes MeW/An: Wddi!/~
Steel
Minimum Yield Slrenglh 10 iOO mill 711ick A9J3/A9I3M-04 Slandard 5jJecijication for HighSlrel/gtll Low-Alloy Steel Shap(!s of Srructura/ Quality, Producl'd by Quenching and Self-Tempering Process (QS7]
A992/A992M-04 Standard Specificatioll for Steel for Structural ShapesJor USl' in Building Framing
User Note: ASTM A992 is the most commonly referenced specification for W shapes.
AWS AS. 17/A5. 17M-97 Specijic(l/j(jh j()r Carbol1 ,\'teel Eleur()(ks and F/uxesj()r '<;Ilbmerxed Arc Wdding
AWS AS. 18:200 I Sj)ec(/icatioll /or Carbon Stec/ Electrodes and Rods/or Gas Shidded Arc Welding AWS AS.20-95 Spec{{icariol1 for Carbon Steel Electrodes jor Flux Cored Arc Weldillg
AWS. AS.23/AS.23M-97 Specificatio" for Low-Allo), Steel Electrodes and Fluxes/or Submerged Arc Weldillg
AlOI I/A10l IM-04 Standard Spec(ficationfor Steel, Sheet
AWS AS.2S/AS.25M-97 5jJeq'(icalionj()r Carbon and LowAlloy Stee! Elec!l'Odes alld Fluxes /or Electroslag Welding
and Strip, /-lot-Rolled, Carbon, Structural, High-Strength Low-Alloy and High-Srrellgrh Low-Alloy wiil! Improved Formabilil),
Alloy Sleel Elecrrodesfor Electrogas Welding
C33-03 Standard Specification/or C()ncrete Aggrl.!gales C330·04 Standard Specification Aggregates for Structural Concrete
for
AWS A5.26/A5.26M-97 Specificationfor Carbon and Low-
AWS A5.28·96 SpecificaTio/l for Lmv-Alloy Electrodes and Rods for Gas Shielded Arc We/ding
Sted
Lightweight
A WS AS.29: 1998 Specification for Low-Alloy Sled Electrodesfor Flux Cored Arc We/ding
El 19-00a Standard Test Methods for Fire Tests of Building Consrruction and Materials
Research Council on Structural Connections (RCSC)
E709-0 I Standard Examination
S'pecification for SfrucfUra! Joints Using ASTMA325 orA490 Bolts. 2004
Guide
Jar
Magnetic
Particle
F436-03 Standard Specification for Hardened Steel Washers F959-02 Standard Specification jar Compressible-WasherType Direct Tensioll indicators for Use with Structural Fasteners F1554-99 Standard Sp(~cificatiol1lorAnchor Bolts, St(?el, 36, 55, and 105 ksi Yield Sfrlmgrh
User Note: ASTM FI554 is the most commonly referenced specification for anchor rods. Grade and weldabiity must be specified. FI852-04 Standard Specification!or "Twist-Off' Type Tension Control Structural Bolt/NutIWasherAssemblies,
501.3 Material 501.3.1 Structural Steel Materials Material test reports or reports of tests made by the fabricator or a testing laboratory shall COI1::\ ; iJ! C sliffi, :CJl! evidence of conformity with one of n'· ,,, ' ASTM standards. For hot-rolled structur,: and bars, sllch tests shall be made in 'ii.X·: ;cI;'"ii(:,' \ :; :.; ASTM A6/A6M; for sheets, such tests sl;:': l~i:' ' 11 accordance with ASTM A568/A568M; lur lubJlIi. :::;d pipe, such tests shall be made in aeco:,·1 '(: wi:', c requirements of the applicable ASTM ~!:'!:d·~rrl<.: 11"",(1 above for those product forms. If requc shall provide an affidavit stating that furnished meets the requirements of the
Steel, Heat Treated, 1201105 hi Minimum Tensile Strength
Association of Structural Engineers of the Philippines
CHAPTEH [) . Steel Hnd Molars
., i
501.3.1 a ASTM Designations
501.3.1< Rolled Heavy Shapes
," ;rnwfIlral .\"/('C'/ material conforming to one of the followi Ilg ASTM speci ficatiolls is ;lppro vC
ASTM A6/A6M hOI -roiled shapes with a nangc thick ness exceeding 50 mill , used as membe rs subj ec l to primary (co mput cd) ten s ile forces du e to te nsion o r nexu rc and spliced using complctc-joint-penclnuion groove welds thilt fu se through th e thickness Ihe member, shall be specified us follows
I.
H OI·rol led struc.:lural shapes
ASTM A16/AJ6M IISTM 11529/11529M ASTM ,,5721 A572M IISTM A5 881 A588M ASTM A 7091 A 709M ASTM A9131 A913M IISTM A9921 A992M
2.
3.
Supplcmcnlary Requircment 530, Charpy V -Notch Impaci
'c.
Pipe
Plmcs
AS,),M 1136/1136M IISTM 11242/11242M IISTM 1128.1/1128JM IISTM 11514/11514M ASTM A529/A529M ASTM 11572/11572M IISTM 11588/A588M ASTM A 7091 A 709M ASTM A852/A852M ASTM AIOIIIAIOIIM Bars ASTM A36/ A36M ASTM 11529/A529M ASTM 11572/A572 M ASTM A709/11709 M 6.
The contract documents shall require thut such shapeo; be supplied with Charpy V-Notch (CVN) impact (cst results in accordance with ASTM A6IA6M.
impact tcst shall meet a minimum average value of 27 J abso rbed energy at +21
1150n 11501 MI8 11847
ASTM ASJ/ A53M. Gr. B 4.
or
Test for 5 lIUciuraJ Shapes - A llernate Core Locat ion. TIle
Structu ral tubing ASTM ASTM ASTM ASTM
5.
!j-31
Sheets
The above requirements do nol apply if lhe splices amJ cOllnections arc made by boltin g. The abo ve requirements do not apply 10 hot-rolled shapes with II flange thickness exceeding 50rnm that have shapes with flange or web clements less than 50 mill thick welded with complete-joint penetration groove welds 10 th e face of til e shapes with Ihicker elements. User Note: Additional requirement s for joiIlts in heavy rolled members are given in Sections 510. 1.5, 510.1.6, 510.2.7. and 513.2.2. 501.3.1d Built-Up He"vy Shapes Buill-UP cross -sections consisting of plates with
oc.
IISTM A606 AIOIIIAIOIIM
Thc above requirements also apply 10 built·up crosssections consisting of plates exceeding 50 111m th
5S I·ISLAS HSLAS -F 50J.3.1b Unidentified Steel Uniden tifi ed slee l free of inj urioll s defects is permitted to be used for unimportant members or details, where the precise physica l properties and weldabiity of the steel would not affect the stre ngth of the structure.
User Note: Additional requirements for j oin ts in heavy built-up members are given in Sections 510.1.5, 510.1.6, .' .. 510.2.7. and 513.2.2. '
th
National Structural Code of til e Philippines 6 Edition Volume 1
[)·32
CHAPTEH
~J.
Steel and Metals
501.3.2 Steel Castings and Forgings Cast stee! shaH conform to ASTM A2J6/A2J6M, Gr. WeB with Supplementary Requircment S 11. Steel forgings shall conform to ASTM A668/A668M. Test rcpOi1S produced in accordance with the above reference standards shall constitute sufficient evidence of conformity with such standards.
Threads on anchor rods and threaded rods shall conform 10 the Unified Standard Series of ASME 13 I X.2.6 and shall have Class 2/\ tolerances. Manufacturer's cCI1ification shall constitute evidence of conformity with the standards.
sufikiclll
501.3.5 Filler Metal ::lnd Flux for Welding
501.1.l Bolts, Washers and Nuts Bolt, washer, and nut material conforming to one of the following ASTM specifications is approved for use under this Specification: I.
Filler metals and fluxes shall conform 10 one ".):' Ihe following specifications of the American VvclcJing Society:
AWS AS.l AWSAS.S AWS A5.17/A5.17M AWS AS.lS AWSA5.20 AWS A5.23/A5.23M AWS AS.25/AS.2SM A WS AS.261 AS.26M AWSAS.2S AWSAS.29 AWS AS.32/AS.32M
Bolts: ASTM A307 ASTM A325 IA325M ASTM A449 ASTM A490 I A490M ASTM 1'1852
2.
Nuts: ASTM A194/A194M ASTM AS631 AS63M
3.
Manufacturer's ceI1ification shall constitute sufficient evidence of conformity with the standards. Filler metals and fluxes that arc suitable for the intended application shall bl: selected.
Washers: ASTM F436/F436M
4.
Compressible-Washer-Type Direct Tension Indicators: ASTM 1'959 IF9S9M
Manufacturer's certification shall constitute sufficient evidence of conformity with the standards. 501.3.4 Anchor Rods and Threaded Rods Anchor rod and threaded rod material conforming to one of the following ASTM specifications is approved for use under this Specification:
501.3.6 Stud Shear Connectors Steel stud shear connectors shall conform to the requirements of Structural Welding Code-Steel, AWS [) 1. 1.
User Note: Studs are made from cold drawn bar, either semi-killed or killed aluminum or silicon deoxidized, conforming to tile requirements of ASTM A291 A29M-04, Standard Specification for Steel Bars, Carbon and Alloy, Hot-Wrought, General Requirements for.
Manufacturer's certification shall constitute evidence of conformity with AWSD 1 1.
ASTM A36/A36M ASTM A193/A193M ASTM A354 ASTM A449 ASTM AS721 AS72M ASTM A5881A588M ASTM 1'1554
sufficicJ!!
501.4 Structural Design Drawings and Specifkatioll.'j
User Note: ASTM F 1554 is the preferred material speeificationfqr anchor rods.
The design drawings and specifications shall meet (lie requirements in the Code of Standard Practice for Stee) Buildings and Bridges, except for deviations specifically identified in the design drawings and/or specifications.
A449 material is acceptable for high-strength anchor rods and threaded rods of any diameter.
Association of Structural Engineers of the Philippines
C Hr~P T E R
S02'}. J3 Gross a nd Nct Arca De(e rmina(ion J. Gross Arc ;! Th e gross arC,I, ('ros s-s l~c t i(l nal
2.
I'.~.
or
a mcm ber is the IOtal
area.
Net Arca The net area. II,,, or a member is the SLIm of the
products of the thickness and the net width of each clcmcn! co mputed as fd!iows : In computing nct arc" for tension and shea r. the width of.1 bolt hol e shall bc taken as 2 111m greater than the nominal di mension of the hole. For a chain of holes extendi ng across a pan in any diago nal or z.igzag linc. the nct width of the part shall
be obtained by deducting from the gross widt h the sum of the dia meters or slot dimensions as provided in Section 510.3.2, of all holes in the chain. and adding, for each g'lge space in the chain , Lhc quanti ty s "!. /4 J: where
s
::;:: longitudinal center· to-center spacing (pitch) of any two consecutive holes, Illlll.
S
;;;; transvcrse cellter·to·center spacing (gage) between fastener gage lines, mm .
For angles, the gage for holes in opposite adjacent legs shall be the sum of (he gages from the back of th e angles less thc thickness.
All
to a maximum
502.4 Classification of Sections for Local !3ucklillg Secti ons are classified
Me !a l~
!) ], ',
502.4. Unstiffcned E1elllelits For unstiffened elements supported along onl y one edge parallel 10 the directi on of the compression loree. the width shall be taken as follows:
I.
For !bnges or I-shaped members and leeS. the width b i ~ oJlc·lwlrthe ful!·t1angc width, bj.
2.
For legs of angles and flanges of channels and lees, the width b is 'the full nominal dimension.
J.
For plmcs, the wid th b is the distanc e from the free edge 10 the firsl row of fasteners or linc of we lds.
4.
For stems aftees, d is taken as the fullnomin4ll depth of the section.
User Note: Refer to Table 502.4.1 for the graphic representation of unstiffencd element dimensions. 502.4.2 Stiffened Elelllents For stiffened clements supported along two edges parallel 10 the direction of the compressionforce, the width shall be taken as follows: I.
For webs of rolled or formed sections. h is th e clear distance between nunges less the fillet or comer radius at each flange; h.. is twice the distance frolllihe centroid co the inside face of the compression flange less the fillet or corner radiu s.
2.
For webs of built-up secti ons, II is the distance between adjaceJll lines of fastene rs or the clear distance between flan ges when welds arc used, and hr is twice the di stance frol11 the centroid to the nearest line of fa<;teners at the com pression flange or the inside face of the compression flan ge when welds are used; IIp is twice the distance from the plastic neutral axis (0 the nearest line of fasteners at the compression flange or the inside face of the compression Oange when welds are used.
3.
For flange or diaphragm plales in buill-up seclions, the width b is the distance between adjacent lines of fasteners or lines of welds.
4.
For flanges of rect angular hollow structural secti ons (HSS), the width b is the clear distance betwee n webs less the inside comer rad ius on each side. For webs of rectangular HSS, " is the clear distance between the flanges less the inside comer radius on each side. If the corner radiu s is not known, b and II shall be taken as the corresponding outside dimension minus three times the thickness. The thickness, I, shall be taken as lhe design walllhickness, per Seclion 502.3 .12.
For slotted HSS welded to a gusset plate, the net area, An, is the gross area minus lhe product of the thickness and the total width of material that is removed to form the slot. In determining the net area across plug or slot welds, the weld metal shall Jlot be considered as addin g to the net area.
User Note: Section 510.4.1(b) limits of 0.85A, for splice pi ales with holes.
5 · Steel :1110
User. Niite: .Refer to ' Tabl~ .. 59ntl;, for , the lIT~phic ~~p'te;2Ilt1i~
th
National Structural Code of tile PI1ilippincs 6 Edition Volume 1
5·3G
CHAPT[n S . S1eel and Metals
iti~,iif'~lUC()jnplres:sioil
Description of Elements
Limiting Width Til ic kness 1Ratio )'p -
Elements
Wiclth~Thjckncss
Ratios """"--1 A/
-""-""" - - -- " - - " " "- ""T"" " - - -" -c -" - "" " "
I\l
111
1·
III
Flexure in flanges of rolled 1shaped sections and channels
I; I I
2
Flexure in flanges of doubly and singly symmetric I-shaped built-up sections
1;11
3
Uniform compression in flanges of rolled I-shaped sections, plates projecting from rolled I-shaped sections; outstanding legs of pairs of angels in continuous contact and flanges of channels
1;11
NA
o 56jtj F,
4
Uniform compression in flanges of I-shaped sections and plates or angle legs projecting from built~up l~shaped sections
I;
I
I
NA
O"64kJ/F,
5
Uniform compression in legs of single angles, legs of double angles with separators, and all other unstiffenecl elements
I;
I
I
NA
Flexure in legs of single angles
"!
I
built~up
For tapered flanges of rolled sections , the thickness is the nominal valuc halfway betwecn the free edge and the corresponding face of the web.
)
Example
i<>i
0"54)£/ F,
502.6 Evaluation of Existing Structures Provisions for the evaluation of existing structures are presented in Appendix A -5, Evaluation of Existing Structures.
502.5 Fabrication, Erection and Quality Control Shop drawings, fabrication, shop painting, erection, and quality control shall meet the requirement s stipulated in Section 513, Fabrication, Erection, and
Quality ControL
Association of Structural Engineers of the Philippines
.,
SECTION 502 DESIGN REQUIREMENTS
The gCIl!!rai rcqui rl!lllC nts I ~)/' the anal ysis and des ign or steel slru<..:tu rcs Ihal i!I\! appiit. : ablc 10 all scclioll of the spc('i li catioll are given in this scctiOl1 . The section is orgilJlizcd as follows: 502 .1 502.2 502.3 502.4 502.5 502.6
General Prov isi ons Loads and Load Combinati on!) Design Basis Classification of Sections fo r Local But:kling Pabrical io n, Erection and Quality Control Eva lua tion of Existing Structures
502.1 General Provisions The design of members and t:onnccl iollS shall be consistent wi th the intended bch.wior of Ihe frami ng system and the assumptions made in the structural analysis. Unl ess restricted by the this code. lateral load resistance and stabilit y may be provided by any combination of members and connecti ons.
502.3.2 Limit States Design shall be based on the principle that no ClppJic
502.3.3 Design for Strength Using Load and Itl'Sis tancc Factor Design (L RFD) Design according to the provisions for Load anti Resistan ce FactoI' Design (LRFD) ~atisfies th e requirements of Ihis Speci ficati on when the desi gn strength of each structu ral component equals or exceeds the required strength detennined on the basis of the LR FD load combinations. All provisions of this Specification, except for those in Section 502.3.4. shall apply. Design shall be perfonncd in accordance with Equation 502.3- I:
R,j $ ¢RIl where
R" = requ ired strength (LRFD) RII = nominal strength, specified in Section 502 throu gh 511
502.2 Loads and Load Combinalions
t/I
loads :Uld load combinations shaH be as stipulated by thi s code. In the absence of a building code, the loads and load combinations shall be those stipulated in SEIJASCE 7. For design pu rposes, th e nominal loads shall be taken as th e loads stipulated by thi ' code.
511 (JR, = des ign strength
TI1C
User No"': For LRFD designs. the load combinations in SElJASCE 7. Section 2.3 apply. For ASD designs. the load combinationS in SElJASCE 7. Section 2.4 apply.
502.3 Design Basis Des igns shall be made according to the provisions for Load and Resistance Factor Design (LRFD) or to the provisions ror Allowable Strength Design (AS D).
502.3.1 Required Strength The required strengt h of stru ctura l mcm bers and con necti ons shall be determined by structural an alysis for the appropriate load combinlltions as stipul ated in tion 502.2.
(502.3- 1)
Sec ~
specified in Section 502 Ihrough
502.3.4 Design for Strength Using Allowable Strength Design (ASD) Design according to the provision s for Allowable Strength Design (ASD) satisfies the requirement s or thi s Specification when the allo wabJe strength of each structural component equals or exceeds the required s trength determi ned on the bas is of the ASD load combin at io ns. All provisions of thi s Specification , except those of Secti on 502.3.3. shall app ly. Des ign shall be performed in accordance with Equation 502. 3-2: (502.3-2) whe re
R. RII
Design by clasLic, inelastic or plastic analysis is p!rm.iltcd. Provisions for inelastic and plastic anal ysis are as slipulated in Appendix I, lnela~ li c Analysis and Design. The provisions for moment redi strib ution in continuous beams ill Appendix A, Section A-J.3 are penllitted for elastic analysis only.
= resislancefactor,
= requ ired s trengt h ( ASD) = nominal s trength , specifi ed
through 5 11 Q = safety fa c tor , s pec ified thr o ugh 5 1 I /l oW = all owabl e strength
in Sectio n 502
in
Sec tion
502
502.3.5 Design for Stability Stability of the struclure and its elements shall be determined in accordance with Secti on 503.
National Structural Code of tile Philippines 6'" Edition Volume 1
5 :J-1
CHAP'-!::" ~ . Sled and MalClls
502.3.6 Dc."lign of CO lln ct'liOlls
Connection clements shall be designcd in ;lccorcbnrc with the provbions of Sections 510 and 511 . The forces and defonll
502.3.8 I)csign for Pondin~ The roof systcm shall be investigated through . . :!"m.:turA anal ysis to assu re adequilte !'trcngth ;111<1 SI :';:: . ;'nd ponding condi ti ons, un less the roof Stlfra<: c. IS !HOVld(' (t with a slope of 20 nl1ll per mc tcr or grc
502.3.6. Simple Connections A si mple connection transmits a negligible moment across the connectioll. In the analysis of the SlruclUrc, simple connections may be assumed to allow unrestrained relative mImi on between the framing clements being connected. A simple connect ion shall ha ve suffi cient ro tatio n capaCit y to acco mmodate the requ ired rotati on dctermin ed by the analysis of the struclUre. Inelastic rotalion of the conncction is pcrmitted .
502.3.6b Moment Connections A momen t co nnection transmits moment across th e co nnec ti on. Two types of momelll co nnecti ons, FR and PR, arc permitted, as specified below. I.
2.
Fully·Restrn ined (FR) Moment Connections A full y·restrai ncd (FR) moment connecti on trJ.llsfers momclll with a negligible rotation bel"'een the connected Inembers. In the analysis of the structure, the connection may be assumed to allow no relative rotati on, An FR con nection shall have sufficient st ren gth and st iffness to maintain th e angle between the con nected members al the strength limit states, Parti all y· Reslrained (PR) Moment Connections Partiall y·rcslrained (PR ) moment connections transfer moments. but the rotation between connected members is not negligible. In the analysis of Ihe struc· ture, the forcc·defonnation response chanlctenstics of the connection shall be included . The response charactelistics of a PR connection s}lall be documented in the {echnical literature or established by analytical or experimclllal me'lns. The componc nt elements of a PR con nection shall ha ve sufficiel1l strenglh, stiffncss. <111(1 dcforl11il1i on capacity at the strength limit Slales.
502.3.7 Design for Serviceability
Thc overall structure and the individual members, and connectors shall be checked for serviceab ilit y. Pcrformance req uirements for servicea bility design arc given in Secti on 512 . co nnections,
F~ I(iguc
Faliguc shall be considered in accordance wilh A !'~" .':lld i-: A·3, Design for p.lIigue, for memhcJ.; :Itjd !: . i connections subject to rcpeated loading. Fali ;'ll' ;It ·d be considered for seismic effects or for the cffl: t.:I~ 01 willci loading on normal bui lding Ia.lentl load resisilll;' ::Y~Ic.! •..: and building encl osure compone nt s. 502.3.10 Design for Fil-c Co nditi ons methods of des ign for fire co ndi tiom; are provided ill Appendix A·4, SlrlIctunll Dr,sij' 1I [Ui ' Fire Conditions : Qualification Testing and I ~ ll ?i)](';:, i,l! ' Analysis. Complianc e with the fire pj( Jlo'd (If, rcquircments in thi s code shall be deemed , il if requirements of thi s sec ti on and Appendix A··of. T wo
I' : ,
Nothing in th is sec ti on is inte nded to cn';,k w i :n IJl~';1 contractual req uircme l1l fo r th e engir::· t r·of H:Ciif(; responsible for th e stru ctural des ign ( : r ::ny f'!OlCr member of the design team .
User Note: Design by qualification [( ~,> iijji'. i:. :h:'. prescriptive method specified in mosi I.)llHdill t I·,de.!;. Traditionally, on most projects where the ::rd rfK,,:1 >, file. prime profcssionaJ, the architect has been i1. ";;!;;'.;: :~'. party to specify and coordinate I:' i,'(J' : ';: " ': 1 requirements. Design by Engineering An:' " i . .- I . \! engineering approach to fire protection. D, ,., """, .. ,.. ,. person(s) responsible for designing for fire rn'ldilin,,' , .. contractual matter to be addressed on cae!: i -; " ; 502.3.11 Design for Corrosion Effect s Where corrosion may impair the 5lrc n g t l ~· " ' n'WI : ":;,;-,' of a structure, sU1lctural componellls sh,,; ,;. \1:" tolerate corrosion or shall be protected a;: ..!-' .t ::\:l I I:~.i ,j ...
502.3.12 Design "Va ll Thickness for 1I ~;:) The design wall thickness, t, shall be lI srti !;l c:'!(':!!':!ions invol ving the wall thi ckness of hol low SUI:' i;;; ,: !-':, . : ;Ol! :: (HSS). The design wall thi ckness. t. sh",: :',. : -'., .. , to 0.93 limcs the nominal wn ll thick i ,. !,,,' t- . ' resistanccwelded (ERW) I-ISS and equal ill ,Ii:: "'-1,; ,: 11:,. thickness for submerged-are -welded (SA \1' ) ; S ;.
Association of Structural Engineers of the Philippin es
CHAPTE R 5 - Steel Clnd Iv1elal$
" '" ~
Dcscription of Elcmcllls
u
W idth Thickncss Ratio
Limiting W idth-Thi ckncss Rati os )",,1
A,
-I.Opi/ F,.
7
Flexure in fla nges of lees
bI I
0.38)E/ F,.
8
Uniform compressio n in stems of tees
dl l
NA
o 75)tjF,-
9
Flexu re in webs of doubl y symm etric I-shaped secti ons and chan nels
h l t...
3.76)E/F,
5.70)E/ F,.
10
Uniform comp ression in webs of doubly sym met ri c I -shaped sections
/i1'1".
NA
t.49)E/F,-
Flex ure in webs of sin glysymmetric I-s haped sec tions
h .. / I".
Mp 2 - 0.(9) My
(0.54 ··Unifonn compressio n in nanges of rectangul ar box and hollow structural sections of unifonn thickness subject to bending or compression; nange cover plates and di aphragm pla tes between of fas teners or welds
Flexure ill webs of rectan gula r
HSS
bl l
1.l2)E/F,-
h/ (
242.Ji,/ F,
Nationat Structura l Code of the Philippines 6'h Edition Volume 1
Examplc
U
[[
5 3;
"'''ll
Description Element s
14
or
Unil<)J"Jll compression ill all other st iffcncd c lement s
Limit ing Width Th ickness Ratios
Width Th ick · Ness Ratio
,,/
{
E};;U llpi;.'
ie, , ,
, I
NA
Circ ula r holl ow sect ions
15
In Flexure
I~I k,.
/J/ {
NA
(U 1 £ 1 1',.
I)/{
Il.07 E / 1',
0.31 Ell',.
In unirorm compression
= -;:;::;::= , but s hall ~, h l r\\"
nol be taken less than 0.15 nor grc;lI l.!r Ihan 0.76 for ca ktd .ttion pU 'l)oscs. (See Cases 2 and ,I)
Ihl Fl. = O.7/~, for minor-axis bending, major axis bending. or sl c l1d ~~ r· wcb built-up I -sllilpcd mcmbers, and major ;,:\; ; bend in g of compacl and nOllcornpact web built-up I ·shaped mcmbers wilh SlI / S" ?: 0.7 ; F,_ = F/·;,I / S" ~ O-SF, for bending of co mpact and JlollcOmpacl web buill·Up I-shaped llll~ ll1h crs with S',J S". < 0.7. (See Case 2)
Associati on of Structu ra l Engineers of tl·1e Pililippirl es
CHAPTEH
SECTION '503 • ,_ . -, .1.\. ".'_" . , '... ' .
·
. _ .',
.
..
,,'
STABILITY ANALYSIS AND DESIGN
•This sc<':lion
adul'l"!sscs general requi remen ts for the slabili ly anal ys is anti desi gn of members and frames.
The section is organized .as fo ll ows: 503.1
503.2
Stability Desigll Requirem ents Calculation of Required Strengths
~
. Slee!
;'lilt!
Me! als
~j 3 ~1
or sat isfying this requ ire men t are provided in Append ix 1\6, Stabilil Y Bracing for Columns and Beams
503.1.3 System Stability Design Requirements Latera l stabi lity shall be provided by morncnlframes, bmccdframcs, shear walls, .lndlor other cquivaicill lateral load resisting systems. The {)vcilurning elTer!s of drifl and the desta bilizing inll ucllcc of gravity loads shall be considered. Force {r::lnsfer and load sharing between clemen!s of the fra ming sys tems shall be considered . Braced -frame and shca r-wlIlI sy5 tclllS, moment rra mc~, gravit y framing systems, an d co mbined systems shall satisfy the fa llowing speci fic requirements:
503.1 Stability Design Requirements
503.1.1 General Requirements S labilil Y sha ll be provided fo r th e struc ture as a whole
for cac h of it s clements. Any method that considers the influence of second-order effec ts (incl ud ing P- tl and P·(5 effects) , fl exu ral. shear and axial deformations, geometric impe rfectio ns, and member stiffness reduction due to
res idual stresses on the stabili ty of the struclUrc and its elemeili s is permitted . T he method s prescribed i n thi s secti on and Appendix A-7, Direc t An alysi s Met hod, SiHisfy these requi re ments . All compo nent and cOllnection <.iefonnations that contribu te [0 the lateral displacements shall be considered ill the stability analysis.
503.1.3a Braced-Frame and Shear-Wall Systems In strucllJres wh ere IHtend stnbility is provided solely by diago nal bracing, shCH r walls, or cqui valent means, the effective length factor, K , for compression members shall be taken as 1.0. unless structural analysis indicates that a smaller valuc is appropriate. In braced-framc systems. it is permitted to design the colu rnns. be;.ulls. and diagonal members ns a vc nically c;;Inlilevered. ~imply connected truss. User Note: Knee-braced frames function as momenlframe systems and should be treated as indicated in Secti on 503. L3b. Eccentri cally braced fram e syslems
function as combined systems and should be treated as indicated in Section 503 . I.3d.
In stru ctures designed by elast ic analysis, individual member siability and slabilil y o f the st ruct ure as a whole are pro vi ded jointly by:
I.
C:.liculation of the re qu ired stre ngth s for mem be rs, connections and other clements usi ng one oflhe methods specified in Section 503.2.2, and
2.
Satisfaction of the membe r Hlld connec ti on design requireme nt s in thi s specification based upon those required strengths.
S03.!.31J Moment-Frame Systems in frames where lateral stability is provided by the flexural stiffness of con nected bemns and colu mns. the effcc ti ve length fac tor K or elas ti c critical buckling stress. Fe, for columns and beam-columns shall be determined as specified in Section 503 .2.
In stmctures designed by inelastic ana lysi s. the provisions or Appendix A ·I . Inelasti c Analys is and Des ign, shall be
satisfied.
503.1.2 Member Stability Dcsig n Requirements Individualmcmber stability is provided by S(l ti sfying the provisions or sections 505, 506, 507.508 a nd 509.
User Note: Local buckling of cross section components can be avoided by the use of compact sections deli ned in Sectio n 502.4.
Where clemen ts arc designed to fUllction as braces to define. the un braced length of colum ns and beams, the bracing sys tem shall have sufficien t sti ffness and strength to control member movement at the braced points. Methods
503.1.3c Gravity Framing Systems Columns in grav ity framing sys tems shall be desig ned based on their actual length (K = 1.0) unl ess analysis shows that a smaller value ma y be used. TIle lateral stability of gravity framing systems shall be provided by momcn t frames. braced frames, shear wa lls, and/or other equi valent lateral load res isting systems. P-IJ. effects due to load 011 the gravity colu mns slwll be Imnsfc.lTed to the lateral load resisting sys tems and shall be considered in the cal<:ulation of the required st ren gt hs of th e lateral load res istin g systems. S03.1.3d Combined Systems The an alysis and design of members. cOllnections and other elements ill combined systems of moment frames, braced frames, and/or shear walls and gravi ty frames shall meet the requirements of thei r respecti ve systems.
National Structural Code of tile Philippines 6'" Edition Volume 1
5-40
CHAP1Tn
~l
.
Steel
503.2 Cuiculation ()f HC(IUircd Strcngths
Except as pcrmitted in Se.ction 503.2.2 h, required strength s shall bc dctcrrnincu lIsing II sCl'o nd -ord cr a na l y~is as specifi ed in Sect ion 503.2. 1. Design hy eit her second-order or lirst-ordc r an alysis shall mee t the requ irements speci fied in Secti on 503,2.2. 503.2.1 Melhods of Second-Ord er Analysis
Second-order an ti lysis shall confo rm to the requ irements in this Secti on. 503.2.1. General Sccond-Orde,· Elaslic Analysi.'
An y second-order clastic anal ysis method thai cOllsiders both P-6. and P-o cffeclr may be used.
obtained. for instance, by a firsl-orderelastic ana lysi s) by Ihe 8, amplifie r, in other word s, M, B2(M"1 + Mil }.
=
/J,=
and
a = I.OqLRFlj
503.2.10 Second -Order An.lysis OJ" Amplified FirS!Order Elastic Analysis 1',
Uscr Note: A meUtod is provided in thi s section to account for second-order effects in frames by amplifying the axial forces and moments in members and connecti ons from a firs t ~ ord er analysis.
(503.2-l a) (503.2- 10)
PI,
C",
a= 1.6c(AS~
= requ ired seco nd-order Oex ura l strength usi ng LRr-O or ASD load combi nations. N-llllll = fi rst-order moment using LRFD or ASD load combinations, assuming there is no lateral translation of the frame, N- mm = firs t-ord er moment using LR FD or ASD load co mbi nat ions caused by 1
where
__ -,C,-,, ",,-_
(503. 2- 3 )
Uscr Nole: Note th at the 8 , ampl ifier (Eq. 503.2-3) can be estimated in preliminary design by using a max imum lateral drift limit corresponding to the story shear H in Equation 503.2-6b.
The amplified First-Order Elastic Analys is Method defined in Section 503.2. 1b is an accepted mcthod for second-order clastic analysis of braced. moment, ,Hld combined fram ing sys tems.
The following is an approximale second-order analysis procedure for calculating th e req uired n exural and axial stre ngths in mc mbers o f lateral load resisting systems. The rcqu ired second-order fle xura l st rcngth, Mr. and axia l strength, PI", shall be determin ed as follows:
"I
L /~'2
M,
I !s
1_ aL /~~1I
For beam-co lu mns not subject to Intnsvcrsc loading between SUPP 0l1S in the plane of bending.
(503.2-2)
(503.2-4)
For members subjected to axial compression, lJ, may be calculated based on th e first-o rd er es timat e PI" Pili +
where MI and 1'4 1 , calculaled from a fi rs!orde r anal ysis, arc th e small er and larger moment s, respecti vc ly. ill (he cnd s of lil,ll p0l1i on of th e member un bn.lced in the plane of bending under co nsideration. M/Ml is positive when the member is ben( in reverse cu rva ture. negative when bent in single curvature.
I- a
1', /1'"
"I
=
P i t.
User Note: ill is an amplifier to account for second order effeclS caused by displacements between brace poin ls (P-S) and B, is an amplifier to accoun t for second order effects caused by displacements of braced points (1'-6.) .
:s
For me11lbers i~ .w~ich .!l, 1.05, il is conservative to amplify Ihe sUm of Ihe .non-sway and sway momenls (as
b.
For beam-columns subjected 10 transverse loading between supports, the value of C... shall be detennincd either by analysis or conservatively taken as l.0 for all cases.
Associa tion of S truclura l Eng ineers of the Ph ilippines
CHAPTE: H ~ . Steel and Metals
',.
503.2.2 Des ign Require m e nt s
P l=~
(503.2·5)
,'. (K,Lj2
P",
= CI,ISlic
crilkal
!i·o11
rcsi ~ I ;IIl (:l'
buckling
of
Ihclll!.!mbcr in the plane of hcndil1!!. (,.' lIk'ulatcd based olll hc m;su!1l ption oj' zcm side.sway. N.
= clasti c cri ti ca l buckling resistan ce for (h e story determ in ed hy sidcs way bu ck ling,:HIl
For moment fram es, where sidcsway buckling effect i ve K~ nrc dete rm ined for thc col umns, il is perm ined 10 calculate thc c last ic slOry sides way buckl ing
'Illesc requi rcments apply 10 all types of braced. momcnt, and combined 1i~\lll i n g sys tcms. Whcre the ratio of second· orde r drift 10 first ·order drift is cqual to or less lhall 1.5. lilt, required ~ Ircnglh s of members. conneclions and other clements shall be determined by one of Ihe methods specified in Sections 503.2.2a or 503.2.2b, or by the Direct Anal ysis Method of Appendix A-7. Where the ratio or seco nd··order drift to first ~ order drift is grcater ,th an 1. 5, the required st rength!,; shall be determined by the DiI·eel Analysis Method o f Appendix A· 7.
lengt h fac(ors
User Nole: The ratio of second-order drift to ftrst·order drift can be represented by 82. as calculated using Equation 503.2·3. Alternatively, the ratio can be calculated by comparing ule results of a second-order analysis to the results of a first-order analysis, where the analyses are conducted eiuler under LRFD load combinations directJy Or under ASD load combinations with a 1.6 factor applied to the ASD gravity loads.
rcsi slancc as
I.I'" =I
1[ '
Ef
(503.2·6,,)
(K ,L)'
For a ll IYPCS of lalc l" ll load resisti ng s),ste ms, il is pen n itied 10 lISC
For Ihe methods specified in Sections 2.2a or 2.2b: (5032·6b)
I.
Analyses shall be conducted according to the design and loadi ng requirements specified in either Section 502.3.3 (LRFD) Or Section 502. 3.4 (AS D).
= modulus of elast icit ), of steel =200 000 MP"
2.
.- ! .O for braced-fmllle systems; 0.85 for momclH-frame and co mbi ned syste ms, unless a larger v.tltle is justified by analysis
The st ru cture shall be analyzed llsing the nom inal geomet ry and the no mi na l elastic sliffness for all elements.
503 .2.23 Desig n by Second-Ord er Analysis
where E
= moment of inertia in the planc of bending, mm
L
K,
K2
4
= slUry height, Illlll = effective length factor
Where required stre ngths are determ ined by a sccond·order analysis:
in Ihe plane of bending,
I.
'nlC
provisions of Section 503.2. J shall be satisfied.
calcul ated based on the assumption of no lateral translation. scI eq ual to 1.0 un less analysis indicates Ihal a sma ll e r value mny be used = effective length factor in the plan e or ben ding, calculated based on a sidcswa y buckling analysis
2.
For design by ASD, anaJyses shall be canied out under 1.6 timcs the ASD load co mbinations and the rcsults shall be di vided by 1.6 10 obtain the required strength!';.
USCI' Nole: TIle amplified first order analysis metllod of Se<:tion 503.2.lb incorporates the 1.6 multiplier directl y in the 0 and lh amplifiers, such that no other modificati on is needed. 1
User Note: Methods for calculation of
K2
are discllssed
jn the AISC Commentary.
1:11/
r.,.,
J.
= first-order i lltt.~rs{()ry drift due to Imeral forccs, mill. \Vhcrc flu varies over Ihc-plan area of the st ru cture. !J. II shall be th e average drift weighted in proportion to vcrliC
All gravity-onl y load combinati ons shall incl ude it min imuill Ialeral load applied a( each level of the Slnlc(ure of O.D02}',-, where Yi is (he design gravity load applied at level i. N. This minimum lateral load shall be considered independently in two orthogonal directions.
User Note: The mini mum Jaleral load of O.OO;2Y/, in conjuPclion wilh the oute'r design·alH;lysis cOristrilirits lisied .' htlhlS section, liriiitS Ihe en-at . that would oUlerwise be caused 'by neglecti~g' initial out-of-plumbnes,
National Stru c tural CoeJe of the Ph ilippin(~s G Edition Vol ume 1 th
..~
and member stiffness reduclion due to residual stresses in the analysis. :1.
Where the ralio of second-order drift 10 lir$I-Ord~f drift is less Ihall or cyual 10 1.1, members ilrc permitted 10 be designed using K = 1.0. Otherwise. columns and heam-columns in moment frames shall be designcd using a K fnctor or co lumn buckling Siress, Ft', det ermin ed from a si desway buckling an:! ~ ysis of the slniclUre. Stiffness reduction adju:il:nel1t due to column inelasticity is p!;rmillcd in Ihc determination of the K factor. For braced frames, K for compression members shall be taken as 1.0, lIllless structural analysis indicates a smaller value may be used.
This additional ialcr:1i loml shall he independemly in two 011 hogonil I directions. 3.
The non -sway :llIlpliliCiUioll or hea nH :olumn 11I{)!IlCntJ; is considered by i1pplying th e JjJ amplifier of Seclion 503.2.l to the IOlal member momellls.
503.2.21> Design I>y First-Order AnalYSis Required strengths arc permitted 10 be dcterminc:d by a fina-order an'llysis, with all members designed using K 1.0. provided that
=
!.
The: n.'tllJircd compressive strengths or all mcmbers whose flexural stiffncsses are consitlcred to contribute 10 the lateral stability of the stn.lcture sati sfy the following limitation: aP, $ 0.5/\
(503.2-7)
where
a = 1.0 (LRFD)
1\
2.
a = 1.6 ( ASD)
= required axial compressive stre ngth under LRFD or ASD load combinations, N. = mcmbcr yicld strength (= A F.,.), N.
P,
All load combinations include an additional la teral land, Nj , applied in combination with other IOtld.s al each level of the stnlcture, where
N, = 2. I (IVL) Yi 2 0.0042Y,
(503.2-8)
where l'i
AIL
6
L
= gravit y load from the LRFD load combination or 1.6 times the ASD load combination " pplied at level i, N. = the maximum rario of f1 to L for all stories in the structure = first-o rder intcrs!ory drift due to the design londs, Illlll . Where /J. vaJies over the plan area of the stnlcturc, 6. shall be the average dli fl weighted in proportion to vertical 10:(\<1 or, altcmtltivcl y, the maximum drifl. = story height, mill . . ·d rift tJ.
is
c~culatcd
<':ollsidcrcd
urider .Lil.FJjload
"·'idfto "r un
Association of S tru ctural Engineers of the Philippines
CHAPTI:= n 5 - Sleel and Metals
SEC'I'lON:5(i4 '< :, : . '" :,
1/1, =11.75 (LRFD)
! .'.
])Estgl:~Fj~Am~~ ·FQR :
=2. 00(ASD)
;:: effecti ve n e l <.I rea, 111m 2 = gross arCH or member. mm2 ;:: specified mi nim um yield slreSli of the type or !H ccl heing used, MPa ;:: specified minimum tensile strength of the type of sttel being used. MPH
Thi s sectioll applies 10 members subjec t 10 axia l tension caused by sialic forces aCli ng Ihrough the centroidal fiX is.
F,
The secli on is orgttnizcd as follows : 504. 1
43
where
TENSlbN . .. ' " \ " .' ,
504.2 504.3 504.4 504.5 504.6
0.,
~i
SICIHJc rness Limitations Tensile Strength Area Determination
When Illcmbers without holes arc full y connected by
welds, the crfective net area used in Equation 504 .2-2 shall be as defined in Section 504. 3. When holes arc prescllt in a mcmber with welded end cOllnection s, or at the welded cOJlJleclion in the case of plug or SlOI welds, lhc efrectivc net arcn through the holes shall be used in Equation
Built-Up Members P ill -Con nected MClnbers Eyehars
User Note: For cases not included in this section the following scctions apply:
504.2-2. 504.3 Area Determination
• • • • •
502.3.9 508 5103 510.4. tension. 510.4,3
Members subjcct to fatigue Members subject to combined axi{ll tension and flexure. Threaded rods.
504.3.1 Gross Arca The gross area. A.>:, of a Illember is the total cross· sectional area.
Connecting elements in 504.3.2 Net Arca Block sheau rupture strength at
cnd connections of tension
T he net area, Ar., of a member is the SUIll o f tile products o f the thi ckness and Ihe !leI wid th of each clement computed
members.
as follows:
504.1 Slenderness Limitations There is flO maximu m slenderness limi t for design of members in te nsion. User Note: For members designed on the basis of tension , the slendemess ratio VI' preferably should not exceed 300. This suggest ion does nOI apply to rods or hangers in tensiou.
504.2 Tensile Strength
In computing Ilet area fo r tension and shear. the width of a boil hole shall be taken 2 111111 greater th an the nomi nal di mension of lhe hol e. For a chai n of holes ex tending across a part in any diagonal or zigzag line. thc nct width of the pan shall be obtaincd by dedu cting from the gross width the sum of the diameters or slot dimensions as provided in Section 510.3 .2, of all hol es in the chain, Ilnd addin g, for ellcll gage spilce in the chain. the quamity J)/ 4g
The design tensile strengt h, ¢, /~, . and the allowable tensile
wh ere
strength, I~JQI of tension members. shall he the lower value obtained according to the limit st,l tes of tensil e yielding in th e gross secti on and tensile rupture in the net section.
s
1.
For an glc:s, the gage. for holes in opposite adjacent Icg ~ shall he the sum of the gages from the bac k of the an gles less the thi ckness.
For tensile yieldin g in the gross section :
I~,
= F.r A.'i
1/1, =0.90 (LRFD ) 2.
(504.2- 1)
D, = 1.67
(AS D )
For (ensile rupture in (he net sect ion: (504.2·2)
g
= longitudinal center-to -center spacing (pitch) of any Iwo conseclltive holes. mill . = transverse ce nter-to-centcr spacing (gage) between fast ener gage lincs, mill.
por slotted HSS welded to a gusset plate, the nel area, /\'" is Ihe gross area millus the product of the thickness and the total width of material that is remo ved to form {he 5101. III delcnnining the net area across plug or slot welds, the weld metal shall not be considered as adding to the net area.
th
National Struc tura l Cod e of 1/10 Philippines 6 Ed ition Volume 1
~) 44
CHAPTEH 5· Steel and Metals
(504.5-2)
User Note: Section Sl 0.4.1 (b) limits All to a maximum of O.gSA, for splice plates with·holes.
¢. 504 .3.3 Effetlive Nel Area The clTectivc area of ten ~ i on dClc nnincd
Wi
mcmbers slwll
he
follows: (504.3 · 1)
where U, thc ShCM
I;Jg
factor, is determined ltlO showI'
If1
Table 504.3. I.
Members such as si ngle angles, double angles and WT sections sh
n" =2.00 (ASD)
where
A.,
= 2t(a + (112).
A
= slw rl csi distance from edge of the pin hole to the c:dge of the membe r measured parallel to the direction of thc rorce, mill . = 21 + 16. mm bu t no t more than the aClu,,1 distance from the edge of the hole to the edge of the pan measurcd in the direction nonn.}1 to the applied force = pin d iameter. mill . = thickncss o f platc, mm .
b~1I
d
3. 4.
504,4 Buill-Up I'vl embcrs
=0.75 (LRFD) J1l1ll :!
For be ari ng on the projec ted area of the pin. see Section 510.7 . For yield ing Oil the gross section, usc Equation
504.2-1.
limitations on the longilUdina l s paci n ~, of conncctors betwcen clements in continuou s contac t consist in g of II platc and n shape or two plates, sec Sectio n 5 10.1.5. P OI'
Either perforated cove r plates or ti c. pl
504.5.2 Dime nsional Requir cmcnl s
The pin hole shall be located midway bctween the edges of the member in the directi on normal 10 the applied force. When the pin is expected to provide for ['thrive movement between co nn ec ted parts while under full load, the diameter of the pin hole shall not bc more than I mm greater than the diameter of th e pin.
User Note: The longitudinal spacing of connectors belween componenls should preferably limil the slenderness ratio in any component between the connectors 10 300. 504,5 Pin-Connected Members
504.5.1 Tensile Slrenglh 'n1e design tens ile sirengrh, $)~, . and the allowable tensile
strength. ~.JQt of of pin-connected members. slwll be the lowl~r va lu e obtain ed accordin g to the li mit states of tcm;ilc ruplllre, shear Illpturc, bearing. ,tOd yie lding I.
For tensile J1JplUrc 011 the net effecti\'e area: (504 .5· 1)
rA 2.
= 0.75 (Ll~FD)
0, = 2.00 (AS D)
POI' shear rupture 011 the effectivc area:
Association of Stru ctural Engineers of the Philippj n~) s
CHAPT[ H S - Swel <311(.1 Metals
~)
4:;
,-----------------------------------------------------------------,;,, ' :Ta,b'!~ 504.3.1 , ' , ; , Sheilr~ilg ,Fa~tots forCo~nections to Tension Members ' '.','
C:ISC
2
':. "
'
.
,
.
Description of Element " AlIlcnsion members where Ihe tensio n load is tra ns millcd directl y 10 each or cross-secti onal elcmelHs by faste ners or welds. (except ,IS ill Cases 3. 4. 5 and 6) All tension Ill'! Plbcrs. except plates .mel HSS, whcre the tens ion load is Irans'miHcd to some but nol :)j J of the cross-sectional clemellls by fa stencrs or longitudinal welds (A ltern ately. 1'01' W. M. S and HI', Case 7 may be used,)
3
Alllcnsion members where thc ten sion load is transmitted by transverse welds to somc but not all of the cross -sectional elements.
4
Plmcs where (he tension IO
5
Rotlnd H SS with a single concentri c gusse t plate .
She
u= 1,0
U :::.1_ "i:11
U= 1,0 and All =area of the direct! y con nected elemenls 1,, 2,,' '" U = 1,0 2w> I" 1,5 ""., U = 0.87 1.5w>I"", ,,. U = 0.75
.q~ ~~_l
1 ?I.3D.. 1J = 1.0 D :-:: 1<1.3D ... U =1- :;:1/
x-Din
- ---1----------------_._-,---,---------------+---_.------------1 I ~ H ... U = 1-'' ' '
with a single conce ntric gusset pl.ate
x
Rect'lngular HSS
6
'1 S or HI) ,hapes S v.., 1\. or Tees 7
8
4(8 + 11)
I ~ H ..U=I-;/I
wi th two side gusset plates
>
8'+2811
wilh nange connected with .3 or more fasten-crs per I'Ine ' d' , f' I'
cut f rOIll these shapes . (1 f' U is 1_--c',;:n-",l.::re;::>c"·,,,,o,,ll,-o,,,_,,IOc;a""c.,,::.,,g~;calcu lated pCI' Case 2, the larger with web connected with 4 value is permitted to be used) or more fasteners per line in direction of loading With 4 or more fastcners per line in direction of loading Single angles ( If U is calculated With 2 or 3 fastte ners per per Case 2, the larger val ue is permi lied to be used line in the direction of loading
8'
x--:-:-::---:-:-:4(8+/i)
"r" 2/3d .,, U=0,90 "1< 2/3d '" U=0.85
1-.---- - -- - --+-----"-----1 U = 0.70 U=0.80 U = 0.60
I = length of connecti on, mm, w= plate width, mill ; X;::. con nection eccentricity, mill ; B = overall width of rectangular HSS member, measured 90 degrees to the plane of' the connect ion, mm H = overall height of reclangular HSS member, measured ill th~ plane of th e cSHl nection, 111111 •• ____ _ __ _ _ __ _,_ _ _ _ _ __ __ _ ______ _
National Structural Code of
(1'10
th
Philippines G Edition Volum G 1
5·4G
CHAPTE:H 5 . Steel and Melals
The width of the plale al the pin hole shall nol be less Ihilll 2b,g + d and the mini mum extension. (I, beyond the bCClring end of the pin hole, parallel to the axis of the member, slmll not be less than 1.33 X b 4J The corners beyond th e pin hole me pcnnillcd to be cu t at 45" to Ihe axis of the member. provided the net ,Ifea
beyond the pill hole, on a plane perpendicular La the cut. is not I c.~s than thaI required beyond the pin hole p.lr:Jllcl (() the axis of the member.
This secti on addresses members subject compression th rough the centroidal axis. The scctiPil is organized il S rollows:
i
504 ,6.1 Tensile Strength
"
The i.lvailable tensile strengt h of eyeba rs shilll be determi ncd in accordance with Section 504.2, with A", tak en as the cross-sectional area of (he body.
User Note: For members not included in this section the following sections apply: 508.1 - 508,3
For calcu llll ioll purposes, the width of the hod y of the cycba rs shall not exceed eight tim es its thi ckness .
504.6.2 Dimensiollal Requirem ents Eycbars shall be of uniform thickn ess, witholll reinforcement at the pin holes. and have circular heads wit h the periphery concentric with the pin hole. The radiu s of transition between the circular head and Ihe eyebar body shall not be less than the head diameter. The pin diameter shall not be less than seven-eighths times the eyebar body width, and the pin hole diameter !-i hall not be more than I mm greater than the pin diameter. For steels having F,. greater than 485 MPa. th e hole diameter shall not exceed five times the plate th ickness. and the width of the eye bar body shall be reduced accordingly. A thickness of less than 13 mm is pennissible onl y if external nuts are provided to tighten pin pl ates and fill er plates into snug contact. The width from the hol e (~dge to th e plate edge perpendi cular to the directi on of applied load shall be greater than two~ {h irds and, for the purpose of calculation, not morc th an thiee-fourths times the eyebm' hodywid th.
axi al
General Provisions Slenderness Limillliions and Erfective Lcnglh Compressive Strenglh for Flexural Buckling of Mem be rs withou t Slender Elcmcllis
505.1 505.2 5053
504.6 Eycb;lrs
i
h>
508.4 5lO.4.4
50902
Members subject to combined axial compression and Dcxure. Members subjcci to axi al compression and torsion. Compressi ve strength of connecting elemenL". Composite ax ial members.
505.1 General Provisions The design compressive strength .
¢Ie' 1" 1, and !he
allowable compressive strength . I'n/ n c" ,Ire dClermincU as follows :
The nomi nal cO.'l1prcssive strength, I'n. shall he the lowest value obtained according to the limit states omcxur;;~ buckling, (orsional buckling and nexural-torsional buc kling. I.
For doubly sYlllmelric and singly symmetric members the limIt state of Ilcxural buckling is applicable.
2.
For singl y symmetric and ullsymmetric members,
505.2 Slenderness Limitations and EITective Lenglh The erfectivc length faclOf, K, ror calc ul;lIion or column slenderness, KLlr, shall be detcrmined in accordance with sec ti on 503, where L r
= huerall y unbraced length or the member, ::::; governing radiu s of gyration, mill .
K
= the
effective length ractor accord ance with Section 503.2
Association of Str uctural Engineers of the Philippines
Illlll .
determined
in
CHA P TEf~ [j .
User Note: For members designed on ' the basis of compression. d,e slenderness ratio KUr preferably should not exceed 200.
Stewl aneJ Mutals
505.3 Compressive Strength for Flexural Bucklin g of Members Without Slender Elements
505.4 Compressive Stl'cnglh for Torsional and Flexural -Torsional Buckling of Mcmbt'.fs withou( Slender Elements This section app lies to singly ~Y!ll!1lctric and UIl·... YIll!11Cl rH" members. and cCI1Hin doubl y symmetric members. such
This secti on appli es to compression members with
as cruciform or built-u p columns with co mpact allt!
compHel and noncompact sections, as defined in Section 50~.4, for uniforml y compressed clements.
Iloncompaci sections, as de fined in Secti on 502.4 for uniformly compressed elements. These provision:; arc nil! required for single
User Note: When the tOrsiQ'iJaJ 'iiilb~ -/el@l! is larger than the lateral unbfiiced Iclihlh; 'iJij' ~\>i.iIi:lliy;.to~t!Ul the design of wide l1angeliild~iiiillarWsliaJ*i cbiUffii!s . ..-
The nominal compressive su·cngth. P", shaH be dClemlincd based on !.he limil state of fle xural buckling. (505.3·1 )
Ii
.-U
The nom inal compressive strength, P,!, shall be determined based on the limit states of f1 cx ural- toJ'sion. iI and torsional buckling. as fo llows: (505.4-1 )
I.
The fl ex ural buckling stress, F'r:r. is det ermined as follows: I.
ft·
-KL $4.7 1 r F).
when
or (F,
~
Fcr = 0.658 P, F,.
[
2.
ft
when -KL > 4.71 -
r
F,
For double-angle mcmbers:
(505.3·2)
tcc ~ s hap cd
comprc~s i {)n
wherc Ferr taken as Fer from Equal ion 505 .3·2 or 505 .3-3. for nexura l buck lin g abo ut thc y-axis of .
KL
symmctryand -
r
KL
=-
, and
ry
or (F, < 0,44F,.)
F en
2.
where
= GJ
(5054-3)
A;=2 g
(505.3-3)
Fr
and
O.44F,.)
P,.]
1,
505.5.
For all other cases, Fer shall be determined according Equ ati on 505.3-2 or 505.3-3. using Ihe lorsi onal or nexural~t o rsional elastic buckling stress, F'r, determ ined as follows: 10
::;; clastic
critical buckling stress determined according to Equalion 505.3-4. Sectio n 505.4. or the provisions of Seclion 503_2. as applicable. MP•.
a.
For doubly symmetric members:
b.
For singly symmctric members where), is Ihe ';,: is symmetry:
,,'E (~Lr
F= -
,
User Note: TI,e two equations for ~alcu\ating the limits and ajJpljcability of Sections 505.3{aj"and 505.3(b). one based on KU, and one based on F,. provide the same result.
F=
( F~)' +
l'c,
' 2 f1
c.
r 1-
I-i \ - 4FnF" -----,!.
(Ft'J' + FCl ), !.
For un sYIllI11ctJ"ic members, Fe is the 1\)\'. \ · i the cubic equation :
1h
National Structural Code of the Philippines 6 Edition Volume 1
, ,j
:U( II
oj'
5· tH.!
CHAPTEH 5 ' Steel and MeWls
)( -XO )2 (F{' - F('.r )(Fl' -Fl'y )(Fe _Ieez )_Ft' 2(F'(' - Iee y
"',
_P(' 2( F(' -p( ' \ ' .
)(X- o )'_ F~ 2( FI' - Fe x )(Y") =o ~
~
(505.4-6) where
e...
-2
2
2
I .. "" J )'
(505.4-
ro ::; x" + y + - - /. As
The effects of ccccmricity on single angle members arc pcnniUcd to be neglected when the members arc evaluated as axially loaded compress ion members using one of the efleeti ve slenderness ratios specified below, provided tllat: (I' members are loaded at tllC ends in compression through lilt.. same one leg; (2) members arc attached by welding or by mjnimum twoHbolt COIUlCCtions; and (3) Ihere arc no intermediate trans verse loads.
:::: gross arei~ of member, mm 2 : : warping constant , mm b
A,
505-3 or Section 505-7, as appropri ate, for axially loaded members, as well as those subject to the slcndcmess modification of Secti on 505-5(a) or 505-5(b), provided th e members meet the cri ICrl (\ imposed.
I.
For equal~ l cg angles o r unequal-leg angles conn ected throu gh the longer leg that are individua1 members o r arc web members of planar trusses with adjacent web members atl ached (0 the same side o f the gusset plate or chord:
a.
when
7) )
2
11=1_..to +yu
-,r
(505.4 -8)
D
(K,,, L)'
L
05- 580: '-x
(505 .4-9) r
~
7(2
E
(505.4- 10)
/'" =(KrLJ'
b.
I)'
w
r ;:
G l x, i y
2
+
Xo , y o
r,
rx KL
..
(505.5-1)
> 80: =
32+ 1.25 -
L
,.,
I'
$ 200
(505.5-2)
(505.4 - 11 )
-2
iI,r,
:::: shear modulu s of elast ici ty of steel = 77 200 MPa. :::: moment of inertia abo ut the princi pal axes. mm4.
J K,
L
wben -
-
F=("'(K,L) EC GJ)_I-
r
= to rsio nal cons tant, mm'! . :::: effec ti ve length fac lor for torsi onal buckl ing :::: coordinates of shear center with respect to the centroid. mm. :::: polar radiu s of gyration about the shear center, mm. :::: radius of gyration about y-ax is, mm.
For unequal· leg angles wi th leg length rali os less than 1.7 and connected through the shorter leg, KU,. from Equations 505 .5- 1 and 505.5-2 shall be increased by adding 4 [(bib.,)' - I], but KU,. of Lbe members sball not be less than 0.95U,., .
2.
For equal-leg angles or unequal-leg angles connect ed through tbe longer leg that arc web members of box or space trusses with adjacent web members attached to the same side of the gusset pl ate or chord:
a.
when
L
05- 5 75: rx
User Note: For doubly symmetric I-shaped sections, r
C w may be laken as I yh; / 4, where 110 is tlle distance between flange centroids, in lieu of a more precise analysis. For tees and double angles, omil tenn with Cw when computing F" and take X o as 0,
505,5 Single Angle Coml>rcssion Members The nominal compressive strenglh , p~, of single angle members s hall be detenni ned in accordance with Sect ion
b.
L
wben -
rx
(505 .5-3 )
> 75:
':1'
KL
-
r
L
=45 + -$200 rx
Association of Structura l Engineers of the Philippines
(505.5-4)
CHAPT EI1. 5 . Slee l and Metals
For 1Illcqual· leg angles with leg length ratios less than 1.7 ,lIld connccted through the shorter leg. KU,. rrom
""Iuations 505 .5-3 and 505..1-4 shall be increased by adding 61(bl1>,)' - II. but KU,. of the member shall not be less than 0.82I1r"
(
~~~)
54Y
= modified column slenderncss of buil l-Up
'"
(~L)o
member
= column slenderness or bu ilt-up member
where
acting as a ullit in th e buckling L
::: Ic ngth of member between work point s at truss chord centerlines. mm . = longer leg of angle. mm. = shorter leg of angle. mm. = radi us of gyration about geometric axis parallel to connec ted leg. mm. == radius of gyration (,or the minor principal axis. mm.
b/
h, I's
r:
3. Single angle members with differem end conditions from those described in Section 505.5(.) or (b). with leg length ratios greater than 1.7. or with transverse loading shal l be evaluated for combined ax ial load and nexurc using the provisions of section 508. End connection to different legs on each end or {Q bothlegs, the usc of singlc bollS or the attachment of adjacent web mcmbers to opposite sides of the gu sset plate or chord shall consti Lute different end conditions requiring the use of seclion 508 provisions.
505.6 Built-up Members
;::
f,
. ;::
= radius of gyra t i on of indi vidual component relative to its ccntroidaJ axis parallel 10 member axi s of buc kling. mill. == separation rati o;:: hl2rib == distance betwccn ce nt roids of individual compo nent s perpendicular to the member axis of buckJing. mill .
'ill
a If
2.
distan ce between connectors. mill. minimum radius of gyration of indi vi dua l component. mill.
The nomina! compressive strength of built -up members composed of two or morc shapes or plates wi th at leas{ onc open side interco nnected by perforated cover plates or lacin g with tie plates shall be detennined in accordance with Sections 505.3. 505.4, or 505.7 subject to the llloditicatiOil given in
Section 505.6.I(a). 505.6.2 Dimensional Requirements
505.6.1 Compressive Strength 1. The nominal compressive strength of built·up members composed of two or more shapes that are
interconnected by bolts or welds shall be determined in accordance with Sectio ns 505.3. 505.4, or
505.7 subject to the following modificati on. In lieu of more accurate a nal ysis. if the bucklin g mod e involves relative deformations th at produce shear force s in the connecto rs between individual shapes.
•.
d ir ection bein g considered (l
Individual components of compression members composed of two or marc shapes shall be co nnccted to one another at intervals, a, such that the effecti ve slende rness ratio Ka/ri of each of the component shapes, between the fasteners, docs not exceed three·fourths limes the govcming s lenderness ratio of the built-up member. TIle least radius o f gyration, rio shal l be used in computing the slenderness ratio o f each component part. The end connection shall be welded or pretensioned bolted with Class A or B faying s urfaces.
KUr is replaced by (KUr)m determined as follows: For intermediatc conncctors
that are snug.tight
bolted:
User Nore:. It is apceptabl~ ..td , design .. a bolto,d ' eod
of
a.bJiUt,up coinPfl'Ssi9tl: 1I)ernbe\' for tbefuU oomp~iW ·l6iithvith,.\liiIt,ii{l.. ,Sh~..andi/)olt :~.'!iues. bal;cd corinectioii
b¢iuing;v
OD:
(505.6-1)
b.
For interm ediate connectors that arc welded or prelcnsioned boil ed:
a , (..'!...)' ' C).. Pl '.,. KL
•. 082
(505.6-2)
intended 'fdifue -resistanCe 'tIf the ax'iaHorce.in.tM·i;mill-up member, but~~tlie:r to PIJiveiit ;.elaiiv~ moyement· between tlle c~niP9ji~n~ "at jile ,~nd ;a.s .tl1e Quiltiup.}g~mtxrr t!l,k!lsa curved $hape: ' . ' : : '",. At the ends of buih·up compression mcmbers bearing on base plates or milled surfaces, aU components in colllact
Witll one another shall be connected by a weld having a length not less than the maximum width of the member or
by bolts spaced longitudinally not more than four diameters apart for a distance equal to II f2 times the maximum width where
of the member. National Structural Code of the Philippines 6'" Edition Volume 1
Along the ICIlgih or buill-up cOlllprcssi()n members betwecn thl: l~ l1d connections required above , longitudinal spacing for i!llCfm illCIlI welds or bolts shall be adctluatc 10 provide for the transfer of the rC
ollc-half of Ihis di stance. The Ihickness or lie plll{cs sh
tilnes O.7SJ 1~1 Fy , nor 305 mm, when intermittent
Lacing, including nat bars, angles, chan neb, or other shapes employed as lacing, shall be so spaced Ihat the Ur ratio of the flange included between their connections shall not exceed tiu'cc-fourths times the govcming slendemess ratio for the member as a who le. Lacing shall be proportioned to provide a sheari ng strength nonnal to ~,e axis of Ihe member equal to 2 percent of the available compressive strength of the member. The Ur ratio for lacing bars arranged in single systems shall not exceed 140. For double lacing this rati o shal l not exceed 200. Double lacing bars shall be joined at the intersections. For lacing bars in compression. I is pemlitted to be taken as the unsupponed length of the lacing bar between welds or fasteners connecling it to the components of the built-up member for single lacing, and 70 percent of that distance for double lacing.
welds arc provided along the edges of the components or when fasteners arc provided on all gage lines al cach section. When fHslcnen; are staggered, the maximulll spacing on each gage line shall not exceed the thi ckness of Ihe Ihinner oUlside plale limes 1.12JE/ F y nor 460
mm . Open sides of compression members built up from plates or shapes shall be provided with continuous cover plates perforated wilh a succession of access holes. The unsupported width of such plates al access holes, as defined in Section 502.4, is assumed to contribute to the available strength provided the following requirements are mel: 1.
The widlh-Lhickness ratio shall conform to the limitations of Section 502.4.
User Note: ]{ is conservative to use the limiting width/thickness ratio for Case 14 in Table 502.4. 1 with the width, b, taken 'as the transverse distance between the nearest lines of fasteners. The net area of the plate is taken at the widest hole. In lieu of tills approach, the ·limiting width · thickness ratio may be detennined through analysis
User Note: TIle inclination of lacing bars (0 the axis of~~ member shall ~referably be not less than 60· for si;',~L~: lacing and 45 for double lacing. When the distaij~ between the lines of welds or fasteners in the f1ange~'iJ~l more than 380 mrn, the lacing shall preferablY';' IJA double or be made of angles. ..".<.:; For additional spacing requirements, sec section 510.3.5. 505.7 Members with Slender Elements
2.
The ratio of length (in direction of stress) to width of hole shall not exceed two .
This secti on applies to compression members with slender sections. as defined in Section 502.4 for unifonl1ly compressed elements.
3.
The clear distance between holes in the direction of stress shaH be not less than the transverse distance between nearest lines of connecting fasteners or welds.
The nominal compress ive strengt h, P", shal l be delerminctl based on {he limit states of flexural, torsional and flexural· torsional buckling.
4.
The peliphery of the holes at all points shall have a minimum radius of 38 mm.
As an alternative to perforated cover plates. lacing with tic plates js permitted at each end and at intennediate points if the lacing is interrupted. Tic plates shall be as Ilear the ends as practicable. In members providing available strength, tile end tic plates shall have a length of not less than the distance between the lines of fasteners or welds connecting {hem to the components of the member. Intermediate tie plates shall have a length not less than Association of
Str~ctllral
(505.7-1 )
a. when -KL $4 .71 ~E - -
QF,.
r
Fa
Ql'l
~ Q O.658/~ {)'
[
Engineers of the Philippines
(505.7-2)
~.
2.
h. when -KL > 4.7 1 - - '-. r QI';.
(or r~,
< 0.44Q1'.,,)
I~, = 0877f'~
(505.7·3)
a.
using Equations 5053·4 and 505.4-4 for
Ek,. F.\.
(505.7-7)
Q, = 1.0
clas tic <.:ritical buckling stress, calculated
doubly sYlnll1ctric members, Equations 50,5..3-4
1*
b
whcn - ,; 0.64 - I
where Fr
For Ilangcs. angles. and plates projecting from bu ilt up columns 01' other compression members:
h.
pJ,'k
members, except for single angles where F, is 1.0
Q
for
members
with
compact
and
noncompac( sections, as defined in Section
502.4, for uniformly compressed elements
Q,fQ(I for
members
with
when
c,
slender-element
sections. as defined ill Section 502.4, for uniformly compressed elements,
User Note: For cross sections composed of only stiffened slender elements, Q Q, (!2. = LO). For cross sections
=
composed of only stiffened slender elements, Q = Qa (Q, = 1,0). For cross sections composed of both stiffened
Ql =
I, ,.
F,
Q,=1.415 -0.6
calculated using Equation 505.3-4.
PF.'k
0.64 - " < b/I ~1. 17 ~
when
and 505.4-5 for singly symmetric members, 41lld Equmioll 505.4-6 for unsYlllmcl ric
{")Rt"· (
(505.7-8)
-' Ek(.
'k
~
b/I > I. 17 -:!-\ 1- ,
O.90Ek ,.
F,m
(505.7-9)
2
where k =_ _ 4_ and shall not be laken less than 0.35 nor
, Jh1I:
and unstiffened slender elements, Q = Q, Q, .
grealer than 0.76 for calculation purposes
505,7.1 Slender Unstiffened Elements, Q, The reduction factor QJ for slender unstiffencd elements is defined as follows:
3.
For single angles
For flanges. angles, and plates projecting from rolled
a.
when -b ~ 0.45 -
I.
columns or olher co mpression members:
a.
b
~
when -~ 0.56 I
-
Q,. = 1.0
E
F,.
b.
Q, = 1.0 b.
v!i
i '7 ) (F; =1.415-07\ b
when 0.45 JE/ F,
Q,=134-07{lf)H (505.7-5)
c.
, F,(7)'
Q., =
(,,)2 F Y I
(505.7-6)
(505 .7- 11)
when bIt> O.9 IJE/ Fy
Q = _._~~3E
0.69£
(505.7-10)
(505.7-4)
when O.56JtjF,
Q,
J*
I F ,.
(505 .7- 12)
where
" 4.
= full width of longest angle For stems of tces
National Structural Code of the Philippines 6'" Edition Volume 1
leg, rulll.
5-52
CHAPTER 5 . Steel and Metals
whe n
iI.
2.
~$().75 r~
{i ;.
I
Q•. =1.0
seclions of uniform Ihickne" wilh
.1*'
'f ~ 1.40J!j:
(505.7- 13)
1*.
(505.7- 18)
when 0.75 -:-
b.
Fy
/ 'y
Q, = 1.90S- 1 2{
c.
For flanges of square and rccl 'lngul ar slender-element
where
!f-)fi
/= P,/A'f!
(505.7- 14)
' 1*
when tI/ l > 1.03 -
Fy
Q,
0.69£
(505.7- 15)
F·ur
3.
For axially-loaded circular sections:
when
where
b
=width of ullstiffcned compression element, as
d
= th e full llomi nal depth ortee, mill .
£ D £ 0. 11 - < - <0.45 Fy
) ~Q =..'l..038£
defined ill Section 502 .4, mm .
Q
:;: thickness of elemem. TllJl1 .
I
,
D
:;: out side diameter, mill . = walllhickness, mOl.
A,f!
(505.7-16)
A
where
:;: total cross-sectional area of member, mm 2 . :;: summation of the effec tive areas of th e cross
A A ~1f
section based on the reduced effective width, be, mm2 .
'nlC
reduced cffccH ve width, b", is de termined as follows:
I.
For uniformly cO l1wresscd slender elements, with
~. ~ 1.49 fI, except I
VI
flanges of square and
rectangular sections of uniform th ickness:
where f is laken as Fa will! Fa calculaled based on
+3.
F,{D/l) 3
where
505.7.2. Slender Stiffened Elements, Q. The reduction factor, Qo for slender stiffened elements is defined as follows:
(2,=-
f 'y
Q= 1.0.
Association of Structulal Engineers of Ihe Philippines
(505.7-19)
and the nominal Ilcxural strength. M,I' shaH he dctcnnincd according to Sections 506.2 through 506. 12. This section applies to members slIbjec t to simple bending about OIlC pJim:ipill Ilxis, For simple bending, (he member is loaded in a plane parallel to a plincipal axi s that passes througl~ the shea!" cCiHcr or is restrained ngai nst twisting at load POJll!S and suppons , The .section is organized
506.1 506.2 506.3
506.4
5065 506.6 506.7
506.X 506.9 506.10 506. 11 506.12 506.13
User Note: For members not included iri this section the folibiiiing'sdlilins ~~"ly: :: .. ; ., .:. 508.1-508.3 M,mbers ·subject to.biax;a!·flexure or to co.jJiiinciUiexure and1lXi:iiirofee. "... . 508.4 . ,¥ .einbers subject to f1exure;~nd..torsion.
SeCtion 507
.
Memberssubj¢litt!""f~ti
Design
oY· ·· ·,
piOvisiorisJ(jr's~iir: .
:
.. ,
506.1 General Provisiolls
nexura l strength, foll ows:
1,
n
I
c.
=
c;,
lateral~torsional buckling modification fact or for nonuniform moment diagrams when both ends of the unsupp ortcd segment arc braced
and the allowable
A111 If'l/>. shall be determined as
(506. 1-1 )
where
= absolute
value of maximum moment in the
unbraced segme nt, N -mm.
Me
R
II ,
= absolute value of moment at quaner point of the unbraced segmenl, N-mm , = absolute value of moment at centerline of Ihe unbraced segment. N-mm . = absolute value of moment at three-quarter point of the unbraced segment, N-mm, = cross-sectio n monosymmctry parameter = 1.0. doubly symmetric members = 1,0, si ngly symmetric members su bjec ted to single curvature bending = 0,5 +
I,· ',.("
2(!.L)2, 1,-
singly symmetric mcmbers
subjected to reverse curvature bending = moment of inertia about the principal y~axis, mm4. :: momenl of inertia abou t y-axis referred (0 the compression flange, or if reverse curvature bending, referred to the smaller flange. mm'l .
In singly symmetric members subjected 10 reverse curvature bending, th e lat era l~t orsionaI buckling strenglh shall be checked for both n anges. The available flexural strength shall be greater than or equal to the maximulll required Illoment causing compression within the flange under consideration G, is permined to be conservatively taken as J.O for all cases , For cantilevers or overhangs where the frec end is
unbraced, C.
=1.0.
For all provisions in this Section
1'. =O.90(LRFq
R", $3.0
125M",,, 25M,,,,,+ 3MA +4M/J + 3Mc
. .. .
For guidanCe in determining· tlw aiipropriates~tiOllS of tills section to apply, Table User Note 506.1.1 may be used.
The design fl exural strength , rp" M
The provisions in Ihis Secti on arc bnscd on the ass umption that points of supporl for beams imd girders arc rcslmincd against rotation abotH their longitudinal axis.
The following teITI1S are commOiJ 10 the equations in this Scction except where noted:
follows:
General Provi sions Doubly Symmetric Compact l ~Shapcd Members and Chmmcls Bent abou t Thei r Major Axis Doubly Symmetric I-Shaped Members with Compact Wcbs and Non-compact or Slender Planges Dent about Their Major Axis Olher I ~ Shapcd Members with Compact or Noncompacl Webs Benl about Their Major Axis Doubly SymmclJ'ic and Singly Symmetric 1Shaped Members wit h Slender Webs Bent about Their Major Axis I-Shaped Members and Channel s Bent about Their Minor Axis Square and Rectangular HSS and Box-Shaped Members Round HSS Tees and Double Ang les Loaded in the Plane of Symmetry Single Angles Rectangular Bars and Rounds Unsymmetrical Shapes PropoI1ions of Beams and Girders
Append~A,3
2.
fl.. = 1.67 (AS£j
Nalional Structural Code of Ihe Philippines 61h Edition Volume 1
.~
,
5-5 4
CHAPTER 5 - Steel and Metals
In Seclion 506
506.2
506.3
5064
506.5
Cross Section
T-]
-1-.
II -1--- ±T
Slenderness
Web S len derness
Limit States
C
C
Y, L1'8
NC,S
C
LTB,FLI3
C, NC,S
C,NC
Y, LTB ,FLB,TFY
C. NC,S
s
Y.LTIl,FLB,TFY
C. NC,S
N/A
Y,FLIl
C. NC,S
C, NC
Y.FLB, WLB
N /A
N/A
Y, LB
C,NC,S
N/A
Y, LTB, FLD
N/A
N/A
Y,LTB , LLB
Flange
-t-t--LJ 506.6
506.7
506.8
t-+
o -e -
506.9
506. 10
I ____ ~ ___. -1=:.-- / ... "
506. "
.1
N/A
N/A
Y, LTIl
506.12
Unsymmetrical shapes
N/A
N/A
All limit states
Y = yielding, LTD = laleral-Iorsional buckling, FLB ;, flange local buckling, WLD yielding, LLB = leg local buckling, LB =local buckling, C =compacl, NC = non com pact, S :;; slender
= web local buckling, TFY =lension flange
Association of Stru ctural Engineers of the Fhilippines
User Note: For doubly symmetric members with no transverse loading between bnlce po,ints, Equation 506.1 ·1 red uces 10 2.27 for the case of equal en d moments of opposi te sign and to 1.67 when olle end moment equals
zero.
(506.2 ·4)
where of' steel::: 200 oon MPa.
506.2 Doubly Symml'fric Compact I·Slwpcd Members and Channels Bellt about their Major r"ix is
E
: : . modulus
J
This section applies to doubly symmetri c I·shapcd mcmbers
.S'..
= torsional conStam, 1111ll4 . ::: elastic section modulus taken about lhe x-axis, mm).
and channels bellt about their major
webs
a l1d CO mptlCl
flanges
of~ cla s tj ci t y
defined in Section 502 .4.
User Note: All current ASTM A6 W, S, M, C and MC shapes except W21x48, W 14x99, W14x90, W1 2x65, WIO x I 2, W8x31, W8xlO, W6x15, W6x9, W6x8.5, and M4x6 have compac t fl anges for F, :5345 MPa; all current ASTM A6 W, S, M, HP, C and MC shapes have compact webs al F ,.$450 MPa .
User Nole: The square root tenn in Equation 506.2-4 may be conservati vely taken equal to 1.0.
The limiting lengths L/,
'-" =I. 76r,.
The nOllli n
Jf-,-----o -.F,.
E 4=1.95;,-_. 0.7/',
HeSA, I
(506.2-5)
,
-. - . \ 1+ \ 1+6.7{07/'; - . -s/\,JE
Jc
506.2,1. Yielding M .. = M
(506.2·6)
t.=F .,.Z.
(506.2-1 )
where
where
Z
yield stre ss of the t ype of s leel being used. MPa. = plastic sec ti on modulus abolll the x· axis . mm '.
I
506.2.2 Lateral-Tors ional Bucklin g I.
2.
When u. S L,.. thc limit Slale of lateral-torsiona l buck ling does n OI appl y. When L
I'
< LJ. ~ 1...,
M" =C"[M,, -(M" -07l';.s,)(4, =L"J]~M" L, Lp (506.2-2) 3.
r
= specified minimuill
F.
When L" > L.
, =J',C" - -b
(506.2-7)
S,
and
For a doubly symmetric I·shal'c: c= I
(506.2-8a\
For n c han nel:
(506.2-80)
where
= distance between the flange centroids, mm.
II,)
User Note: If the square root lerm in Equation 506.2-4 is conservati vely taken equal to I, Equation 506.2-6 becomes
(506.2-3) whcn.~
= length bl!lwccn points Ihat arc either braced against ]
approximation
Note Ulat this conservati ve.
can
be
extremely
Par dOHP!X sJ.ni'P~lIjc~-strape$ ,'~,;tb re~tangular flanges,
C . ~1;;'~~.~ w
~
...
4· · 'md tliusEqu alion506. 2-7 beCOfQes 111
National Structural Code of tile Pllilippines 6 Edition Volum e 1
A1'.1
:::::
Ap is the lilllillng. skndcrlu::-,:-,
I ~} r it
( (lmpaCI niUlge.
Tahle 502.4 . 1
may bc approximated accurately and conscrvi:UivcJy as the radius of gyration of the compression fl anges plus OIlC.ixth of the web: TIS
A'l::::: }')' is the lim iti ng :-. Icndcrncss ror it Illlil compact !lange,Tahle 502.4 . 1 g
:=
,
~_4~
Jill!..
and shal l nol he take n less {han 0.35 nor ~
grea ter tha n O.76·.for cakul;uioll IHlrposcs.
506.4 Othn J·Shapcd J\1t'll1iJcrs with Com pHer or NOIiCOllllwcl " ' cbs Bent
506.3 Doubly Symmetric I-Shaped Members wil h Comp:'lct \Vcbs and NOllcompact or Slcnciel" FJangt's Dellt about their Major Axis Thi s section applies to doubly symmetri c 1- sll
compilcl or slender Oanges as defined in SectioJl 502.4 . User Note: The following shapes have non co mpact flanges for F,::; 345 MPa: W21x48, WI4x99, Wl4 x90, W12x65 , WIOx l2, W8x31, W8x 10, W6 x 15, W6 x9, W6 x 8.5, and M4x6. All other ASTM A6 W, S, M, and HP , hap"' have com pact flanges for F,,::; 345 MP •. The nomina! ncxu ral strength , M 1/ '
shall he the lower the limit stat es or latcra ltors ional buckling and compression nange l oca l buckling.
value obli.lincd accordi ng
This section
major ax is. wi th COI11I>;l( t
Or' nOll
User Note: I-shaped members for which lhis section is applicable Illay be designed conse rvatively using Seclion 506.5. The nominal Ilc xural strcngth , Mil, shall be the lowest value obtaincd according to the limit stal CS or compression fhmge yielding. laleral -Iorsional huckling. com pression nangc local buckl ing and tension nangc yie ld ing.
(0
506 .4.1 COIllJlression Flange Yieldin g
Mn =R,wM .w· ::; R,K F., S.U·
506.3.1 Lateral-TOI'sional Buckling For lateral-torsional buckling, the provisions of Section 506.2.2 shall apply.
506.3.2 Compression Flange Local Buckling For secti ons wi th non co mpact fl anges
I.
\Vhen!J, ~ LJl. lhc li mit st:.1l e of lateral-torsional buck ling docs not ilpply.
2.
When L"
=+V1" -(~)1" -/).S,{~, =~j]sJS.M" (506.4-2)
(506.0 -1 ) 3.
Fo r sections wit h slender flanges
)..2
(506.3-2)
(506.4-1)
506.4.2 Laleral-Torsional fiu c kling
Al"
M /I .._ _0_ .9_E""k-'..,,_~x'-
compact wcbs, as defined
in Sec ti on 502.4.
\Vh c n
1.111
4, > L =:
1'~, S\l :5
where
Association of Stru ctural Engineers of the Philippines
R ill
M ".
(506.4-3)
M " I S""S' (50(, 4 ·4 )
=2" r .•. -;:-/.6S"F, = das( ic section modulus referred [0 tensi ol1 lind co mpressi ol1 nallgcs, rcsp l.!(l ivc!y. Illml
= h, / 1" = l p, the lim iti ng sle nderness for il compact web, Table 502.4 . , = /t, the li miting \Icmlcrncss for a nOllcolllJlilc t
I.
web, Table :')02.4.
'
·' or
!L < 0.20. J ell·,I'lle t IkeIlaszcro _
.••
The effec ti ve radi us of gyration j'ur la teral-torsiollal
i
'.\'
buckling. r( • is determined as follows :
The stress, Fl., is determ in ed as follows:
For I-sh apes with
!.
Sn 0.7 I·",or -.-~
I;
Sx/"
S(I
rccwngular compression Oangc:
b,/.
~
I{ :;
(506.4-6al For _.- <;;0.7 S.U
(506.4- 10)
~
+ "" :.:,:, )
where
r:·1.= ,:\' -S", - >05F - ' \' . Src
"J ... brJ I'·
(t\\ , : : = - --
(506.4 ·6b)
.
The limit ing latc rally ullbra ccd length for the limit stale yielding, L/I. is
or
;;::
:;; co mpression lliinge thicknes s, mm
1',
The limiting unbraccd length for the li mit stme of inelasti c lateral-torsional buckling, Lr, is
E
(/".
J
(506.4·8) The web plaslification factor,
NI,,:, is determi ned as
follows:
111111
For I-shapes wit h chan nel caps or cover plates atlached the compression nange:
10
(506.4-7)
\
compressi on flange width,
bj < 'ic
2.
f'-+'/=I;=6='.7=r{=P =,..=.s=.'= "'=1)=0,
(506.4· 1' )
rad iuS of gyration of the flange components in flexural compress ion plus one-third of thc wel> area in compress ion due to application of n1:ljor axis bending moment alone, mm. ;;:: the ratio of' I wo times the web area ill compression du e to appl icati on of major ax.is ben ding momcnt alone to the area of the co mpression fl ange components
::
User Note: For I-shapes with a rectangular compression r
flange. t· may be approximated accurately and conservatively as (he radius of gyration of the compression flange plus one-third of (he compression porti on of (he web; in other words,
a.
(506.4 ·9a)
b.
506.4.3 COlllpression Flange Locailluckling L
For sections with compacl flanges . (he limit sla te local buckling docs 110! apply.
2.
For sections wi th non co mpact flan ges
w here
National Structural Code
or tl10 Pllilippines 61h Edition Volum e
1
or
:i·~H
~.
C H APTE R 5 . Stcc-!I a ne! M e tals
i.
= 11.11"
} p ll'
::: J.p ,t hc liJllili ng slende rness for
i.nl·
defined in Tabl c 502.4. I ::: )' '-, 1he limit ing slc nde rn ess for ,veb. defined in Tahle 502.4 . 1
;t
c.:ompilt:l web, nOll l'olll pac!
For secti ons wit h slende r flanges
M"
SUfI.5 Doub ly Symmetric ~llId Singly Syml1lctrk 1-
O.9Ek,Sx.. '. A
,
(506.4 - 13)
Major Axis
where Fl.
;:: defined in Equa tions 506.4 -6<1 ,md 506.4-6 b lhe wcn pl astifi cali o n racto r. dete rm i.ned by
RJ/< .
::
Eqmlliolls 506.4-9
k,. =
~
Shap ed Mcmbtl's with Slr lHlc r '""c bs Bent about their
v"/' . · greater thall 0 .76 fo r ca lc ulalion purposes
= (I',.J 2,fo)
This scclioll applies 10 doubly sYllll11c lrk" 'IIH..I singly symmc(ri c 1- slwpcd mc mbe rs wilh sle nde r webs aUl.Ichcd to Ihe mid-w idth 0 1" Ihe !langes. be lli abou l Iheir 1I1:1j Ol" (IX is, as de fin ed in Secti on 502.4 Thc no mimll flex ural sifengih. M". shall be the lowes! value obt ained accordi ng 10 (he lim il slates of compressio n n.mgc yielding, lalc ral-I o rsion al buck li ng. <:o lllprcssio ll llimge IOC'11 buckling and tens io n !la nge yie ld ing. 506,5 . 1 C ompr ess ioll Flangc..' Yielding
:;; 1.11 ,the limiting slenderness fo r il cO lnpact Ilange, Table 502.4.1 = J.,.,the limiting ' slenderness for
!tr1n ::;; Rpgr~\};.I'("
(5065- 1)
50fl.5,2 Latcral-Torsion;d Bu tk ling
506.4,4 Tension Flange Yielding I.
When
(506.52)
SXI ~ Sxc the l imit state of' tensioll fl
yi eldillg does not apply.
2.
Wh e n
I.
:s
Whe n U.
L
th e limil stale of late ra l·torsional
I '.
buckling docs not apply.
SXI < S.\'( .
M il ::: R,J,M yt
(';06.4- 14)
2.
Wh c nL ,. <:. L/.S: L.
where
F
"
C
~
('
I."'-'-1L,,)] S F '
[ F .' - fO.:lF \ { /
.• 1
•
JI
(506.5·3) The we b pl as tifi l:tIl io n faclOr corres po nd ing 10 Ihe tensio n Oangc yieldin g limit st ale, R I •, is determi ncd as fol lows:
.1.
Whe n
LI~ >
L ,·
a. w here
(506.4· 15,, )
h.
It,
L I' is defi ned by Eq ual iO Il
,
For ->11. 11 11' I ".
(II
rA-A''' )J
--) [ M" - (M"
= -
II
M YI
My!
'A.rw-Af/\\'
L ::: r
M"
<-
M YI
(506.4 - 15b) where
1£..r I
S06.4 ~ 7
R,i' -
(506.5-5)
--
O .7 /~\,
RIlf. is the bending stre ngth red uction fac!O r: iI"I'
~I
a".
1200+300(1 \,.
Association of Stru ctUrA l Engineers of the Philippines
(':.r.._' S.7 (I<'
1l),I.O
{i~,
CHAPT En 5
(506.5-6)
M" = M I' = F,.2,. $1.6FrS,. 506.6.2 Flange Local HUl'kling
exceed 10 and
J.
= the erfective radius of gyration for late ral buckling as defined ill Sectioll 506.4 .
I
For Sections with compact Ilangcs the limit yield ing shaH appl y.
(.'i06.5 -7)
For sect ions wit h com pact flanges. the limit si ale of
2.
compression Oangc local buck lin g does not apply.
For sect ions with noncom pact flanges
Mn =M - (M -O.7F.s{ 2-;'"I )S M
'hI - ;'"I
I'
(506.5 -8 )
"[~r
P
(506.6-2) (506.6 -3)
Por secti ons with sle nder flange sections
F
of
For secti ons wit h nOIiCOlllpact flan ges
P
3.
Slat e
Us~rN~J~: All curren! ASTM A6 W,S,M,C and MC shapes excepLW21i<48;W14x99, W14x90, W12x65, . WIOx12, \V8x3!, W8xlO, W6x·lS;: ·W6~9;,·;W6x8!5; arid' M4x6 ·have compact ftingesal Fy =345 Mpa.
506.5.3 ComI~rcssion Flange Local Bu ckling
2.
(506.6- 1)
= defined hy Equat ioll 506.4 - 11 hu t sha ll not
I\"
,.
I.
5·59
506.6 .1 Yieldin g
where
a
SI()c f
wh ere
= 0.9£k,.
(506.5 -9) (506 .6-4)
where 4
k = - - - and s hall no t be la ken less than 0.35 nor c
~h/I"
great er than 0, 76 for
calcu lation purposes
).
= b,,I2I,c
i'pl
= J.p, lhe limiting slenderness for a compact flange. Table 502.4. 1 = .J.r,lhe limiting slenderness for a nO llco mpacl fl angc, Table 502.4. I
J. lf
2.
When SXI ~S:\'{. th e limit state of te nsioll flange yie lding doe s not apply. When 5.rI
M"
= r,.s u
; bit
J.pJ
= Ap,the limiting slenderness for a co mpact fl ange,
i.rf
:::;
Table 502.4. I ~.r,the
li mitin g slenderness for a Iloncompact
flange,Tab le 502 .4 . 1 = for a chan nel shall be taken as thcminimum sectio n mod ulu s
506,7 Square a nd Rectangul ar HSS and Box-shaped Members
506.5.4 Tension Flange Vielding
I.
)
(506..'i-IOj
Thi s secti on applies to square and rectangul ar !iSS. and doubly symmetric box-shaped mCll1bcrs bent abou t ei th er Hxi s, ha ving co mpact or non co mpact webs and co mpact, nOll co mpact or slender Ilangcs as defin ed in Section 502 .4 .
The nomina l Ilcxura l strength. Mil, shall be the lowest val ue obt ai ned acco rding III the lim it stales of yieldi ng (pJa:->tir mome nt ). nangc 10c.1I huckl ing amI web local buckl ing un der pure I1 cxufc.
S06.6 1·Shapcd Members and Chann els Bent ahout th eil'
Mino r Axis This sec tion applies
5(1(, .7 .1 Yieldin g 10
I-sh aped mCmbCf!\ and channels bent
Mil =Mfl:;::: I~.z
about their minor axis.
(506-1- 1)
where
The nomina! ncxura l strength,
11111 " shall be the lower val ue
obtained according to the limit states of yieldi ng (plaslic moment) and flange local buckling.
z
modul us aboll t the 'Ixis o f
:::; plastic section
bending, 111m'
N;l\ional Stru ctura l Code of tllE) Phil ippinc'ls GIll Edition
VOIUlliG
I
:i·GO
CHAPTER 5 . Steel and Metals
j'
506.7.2 Flange Local Buckling I.
For compact sections, the limit state of Ibnge local
O.02IE. M" ~ -.. -~-- + l-y .1 [
buckling does no.! apply. 2.
(506.8-2)
For sections with non compact flanges
3.
For sections with slender walls
{ "j?i'; )
MIFMI' -(MI' "-f;S 1ST - -4.0 "M1, . ,E (506.7-2)
3.
(506.8-3)
where
For sections with slender flanges
F = 0.33E cr
(506.7-3)
s
where S('jf is the effective section modulus determined with the
effective width of [he compression flange taken as: b,
~1.92,
._10. . . [ JF,.
0.38
if] E
. - 1--- -,- "b
bl'
(506.8·4)
D
= clastic section modulus, mm)
506.9 Tees and Double Angles Loaded in the Plane of Symmetry This section applies to tees and double angles loaded in the plane of symmetry.
(506.7-4)
['y
506.7.3 Web Local Buckling 1.
For compact sections, the limit state of web local buckling does not apply.
2.
For sections with non compact webs
The nominal flexural strength, Mil> shall be the lowest value obtained according to the limit states of yielding (plastic moment), lateral-torsional buckling and flange local buckling. 506.9.1 Yielding
Mn=Mp
(506.9-1 )
where Mp (506.7-5) 506.8 Round HSS This section applies to round liSS having Dlt ratios of less
= FyZ;t
(506.9-2)
:::; 1.6M y for stems in tension
(506.9-3)
:::; My for stems in compression 506.9.2 Lateral-Torsional Buckling
0.4510
tlao I --
Mil =Mcr
Fy
ff)ElyGJ [
r:-::z]
B+vl+BH
L"
The nominal flexural strength, M'l'shall be the lower value obtained according to the limit states of yielding (plastic moment) and local buckling.
(506.9-4)
where (506.9-5)
506.8.1 Yielding M,,=M/,=~.Z
(506.8-1 )
506.8.2 Local Buckling
1. 2.
For compact sections, the limit state of flange local buckling does not apply.
The plus sign for J3 applies when the stem is in tension and the minus sign applies when the stern is in compression. If the tip of the stem is in compression anywhere along the unbraced length, the negative value of B shall be used. 506.9.3 Flange Local Buckling of Tees
For non compact sections
(506.9-6) S xc the elastic section modulus referred to the compression flange. j<~rdetermined as follows: Association of Siructural Engineers of Ihe Philippines
CHAP1E H 5
I.
For (.'olllpac t sections, the limit state or flunge local huckling docs not apply.
2.
For nOll comp.lcl sections
Steel and Metal
5·61
(506.10·:1)
. .[
{b Jfi'-"J
/',., = /'y 1.19 - (J.S(
i 21 i
~~
--,. L
(506 .9· 7)
.l
where
A1/. the clastic latcral-Iorsi olwl buckling moment, is ).
For s "~ ndcr sections
dCl c nnincd as follows:
"
I.
F = 0.69E
For bending about one of tile geomeu·ic axes of all cqual-
leg angle with no lateral- torsional buckling I)10mCllI
(~r
iI.
With maximum comprcss ion at the IOC
(506.9-8)
506.10 Singlo Anglo, This secl ion applies to single angles with ilnd without
(506.10-4a)
cOrltinuolls lateml rcstraint along their Icngth . h.
Single anglcs with continuous lateral-torsional restraint along the length shall be pcnlliued LO be designed on the basis of geometri c axis (x.),) bending. Si ngle anglcs without continuous Imeral-torsional restraint along the length shall be designed llsing the provisions for principal axis bending except where the provision for bending about a geometric axis is permitted.
User Note: For geometric axis dcsign , use section properties computed about the x- and y-axis of the anglc, parallel and perpendicular 10 the legs. For principal axis design use section properties computed about the major and minor principal axes of the angle. The nominal flexural strength, 111" shall be the lowest valu e obtained according to the limit Slates of yielding (p lastic moment), lateral-torsional buckling and leg local buckling.
(506.IOAb)
My shall be taken ;\s 0.80 times the yield moment caJculalcd using the geometric sectiorl modulus.
User Note: M n may be taken as My for single angles will' their vcrtical leg lac in compression, and having a span-todepth ratio less than or equal to
1.64E
Fy I.
(!...)2 -1.4 F,. b
E
For bending .tbolll one of the geometric axes of an eq ual-l eg angle withlateral··torsional restraint at the point of maximulll moment ani),
(506. 10·1 ) Me shall be taken as
where M,-
066~;4/C~ ( I+ O.7(~ )+1)
M,
506.10.1 Yielding
M ,,= LSM,.
With maximum tension at the toe
= yicld
1ll0mCIlI about th e axis of
bending, N-
mill .
limes M(, computed using
geometric section !llodulllS.
506.10.2 Lateral-Torsio"al Buck ling For single angles without comilluous lateral-torsional restraint alon g the length (a ) When Mr 5; M,·
2.
For bending abou t Ihe rnajor principal axis of equal-leg angles:
M, M"JO.92-0. 17M')Mr
l
J .25
Equation 506.10·4" or 506.1 0·4b . M .\. shall be taken
M"
(506. 10.2)
3.
0.46b,,',2 CI, L
(506.10-5)
For bending llbout the major plincipal axis of unequal -leg angles:
when M t >M )" th
Nalional Siructtlfal Code of tile Philippines 6 Edition Volwne 1
5 6?
CHAl'lTIl 5 . Sleel and Mela ls
506.1 J Recta ngul ar 1I3rS and Rounds
M'·f~~;lCb)( (pw'+oostJ)+p"')
'nl is section applies to rccwngular bars bent about either geo metri c axis and round s.
(506. 10·6)
Th e nom ina! flcxunl l stren g th , M ", shall he (he low('. 1"
value obtained according
where
\0
the limit stales of yielding
(plastic moment) and lateral -torsional buck ling, :IS required.
ell
= computed
using Equat ion 506. J" I
wi th
a
maximum val ue of 1.5.
506.11.1 Yielding
:: laterally un braced length of II member. =:
minor principal axis
momCllt
111111 ."
of inertia, mm4 .
"..or rcc t'Ulgu l1Irbar Wit' I1 -L"d ,
~
(J.08!i . - bent abou t tIlCl' r major
F'.,.
I
::;: radiu!i of gyralion for the minor principal axi s.
axis. rcctangular bars bent about thcir minor axis. and rou nds:
min.
= angle leg thickness , mm. = a section property for unequal leg angles, positive for short legs in compression and negative for long legs in compression. If the long leg is in compression anywhere along the unbraced length of Ihe me mber, the negative value o f shall be used.
Ph'
(506.11- 1) 506.11.2 Lateral-Torsiona l Buckling
I.
0.08£ L.d 1.9£ ror reclang ular bars with - - < - - $ - - ben! F,. ,2 Fy about their major axis:
User Note : The equation for 3w and values fo r common angle sizes arc lis ted in the Commentary.
M" =C.[1.52- 0.27 {LbdJF ~2' E My ~ M" y
b
]
506. 10. 3 Leg Loca l Bu ckling The limit state of leg local buckling applies when the toe of the Jeg is in compression . I.
(506.1 1·2)
Lvd
2.
For rectangular bars with -2- > -F bent abou t their 1
For com pact sections. the limit state of leg local
For sections with
3.
For sections with slender legs
Mil
110 n
compact legs
=F::rS("
(506.1 1-3)
(506. 10· 8)
where (506.10·9)
b S,.
'y
major axis;
buckli ng does not apply.
2.
1.9£
:; ollt5ide width of leg ill compression, mill. = clastic section modulus to Ihe toe in compression relative to the axis of bending. mm l, For bending abou t o ne of the geometri c axes of an equa l-leg angle with no lateral-torsional restraint , Sc s hall be 0.80 of the geometric axi s
secti on modu lus.
Associa tion of Structural Eng ineers of the Philippines
CHAPTER 5
where
(506. 1 J ·4 )
2.
For Full /'1 < Y, FyA fl>. the nomin al flexural strength. at the locati on of th e holes in th e te nsion flan ge shall nol be taken greater than :
{2
= widlh of rec tangula r bar pcua llcl to axis o f bending, mill , ;;; depth of recwngular bar, in . mill , ;;; length between poillls Ihal arc either braced againsl lateral displ acement of the compression region or braced agai nst (wist of Lhe cross section , in . mm.
1..,.
3.
For rounds and rectangular bars bell( about their minor ax is , the limit stale of lateral*lorsional budd i ng need not be consid ered.
This sec tion applics to all un symmetrica l shapes. except single angl es. The nomin al flexural s trength, M n, shall be the lowest value o bt a in ed according 10 the limit states of yield ing (yie ld moment), lateraJ*torsional buckling and local buckling whe re
Mn =F"S
F;/Afrl M" = -- S,
(506. 13 -1)
Aig
where Alt
;::: gross tension fl ange area , calcul ated in accordance with the provisions of Scclion
AI'I
;;; net tension flange area, ca lculated in accordance
y{
~
504 .3. I. 111m2.
506.12 Unsymmelrical Shapes
with the provisions of Section 504.3.2. 111m2. 1.0 for FIF, S 0.80
;::: 1.1 otherwi se
506.13.2 Proporlioning Limils for I ·Shaped Members Singl y symmetric I· shaped members shall satisfy (he fo ll owing limit:
O.I~/)'c ~0.9
(506.12-1)
whe re S
5·63
docs not apply
F = 1.9EC" cr LlJd
()
Steel and Meta:
(506.13 -2)
I ).
1* shaped members with slender webs shall also sati sfy the following limits:
= lowest clastic modulus relative to the axis o f
bending, mm 3. I . For ~"1.5
"
506.12.1 Yielding
F" =F)'
(.!!..J I1\'
(506.12-2)
= I 1.7 max
[f
V i~y-
(506. 13·3)
506.12.2 LateraI·Torsiol1aI Buckling 2.
-F.cr -
For ~ > 1.5
(506.12·3)
where
Fer
"
0.42E
F"
;;; buc kling stress for the section as dcte rmined by analysis. MPa.
(506. 13·4)
where
506.13 Proportions of Beams and Girders
"
506.13.1 H ole Reductions This section applies to rolled or built -up shapes, a nd COVCI'* plated bea ms with boles, pro portioned on the basis of flexural strength o f the gross secti on. In additi on to the limit slates specified in other sections of this sectio n , the no minal flexural stre ngth,
M'l shall
be
limited accordi ng to the limit state of tensile rupture of the te nsion Oange.
;;; clear distance bet ween tran sverse stiffeners . mill
tn unstiffened girders IJI ... shall not exceed 260. 1l1C ratio of the web area to the compress ion flange aren shall not exceed to.
506.13.3 Cover Plates Flanges of welded beams or girde rs may be varied in thickness or width by spli ci ng a series of plates or by the use of cover pl ates. The total cross-sectio na l a rea of cover plates o f bolted
girders shall no' exceed 70 percent of 'he ,olal fl ange area. 1.
For Fit A/II 2: Y, F." AIe' the li mit state of tens il e rup ture
National Structural Code of the Philippines 6"' Edition Volume 1
.'"., 5-64
,
..'
CHAPTER 5 . Steel and Metals
High-strength bolls or welds co nnccting tlangc to web, or <.:ovcr plate to na ngc, shall be propol1iollCd 10 resist the total horizontal shear resulting from the bendi ng forces on the girder. The longitudinal distri bution of these bolts or inlcrmiucllt welds sha ll be in pro portion to the intensity of the she;IL However. the longilIIdinal spacing shall not exceed the maximum pcmlitted for compression or tension members in Section 505.6 or 504.4, respectively, Bolts vr welds connecting fl ange to web shall also be propollioiled to tran.s mit to the web any loads applied directly to the flan ge, unl ess provision is made 10 transmit such loads by direct bearing. Part ial·length cover plates shall be extended beyond the theoreti cal eUioff point and the extended portion shall be attached to the beam or girder by hi gh-strength bolts in a slip-critical connection orfillet welds. TIle attachment shall be adequate, at U,e applicable strength given in Sections 510.2.2, 510.3.8, or 502.3.9 to de velop the cover plate' s portion of the flex.ural slfength in the beam or girder at the theoretical cutoff point
For welded co ver plates, the welds connecting tlie cover plate termination to the beam or gi rder shall have continu ous we lds along both edges of the cover plate in tile length a', defined below, ruld shall be adequate to develop U,. cover plate's portion of the strength of the beam or girder at the di stance a' from the end of the cover plate.
!.
W hen there is ,I continuous weld equaJlO or larger !hnn th ree-fourths of the plate th ickn ess l.Icross the end of the
plate
[1'=
IV
(506. 13·5)
where w
2.
= width of cover plate, mill
When Ulcre is a continuous weld smaller than lhr('-cfo urths ortlle plate thickness across th e end of th e plate
a' = L5w 3.
(506. I 3·6)
When there is no weld across the end of the plate
a'= 2w
(506. 13·7)
506.13.4. Buill-Up Beams Where two or morc beams or channels are used side-by-sidc 10 fonn a fl exu ral member, Lh ey shall be connected loget her in compliance with Sec tion 505.6.2. When concentrated loads are carried from one beam to another, or distributed between the beams, diaphragms having sufficient stiffness to distribute the load shall be welded or bolted betw c(",u the beams.
Association of Structural Engineers of the Philippines
CHA PTER 5
Steel and Melal
5-65
h/I... 0; 224) Ej F,. This secti on :lddresses we bs of singl y or doubly symmetri c members subjec t II) shear in the plane of the web. single anglcs and /iSS sC( lions. and shear in the weak direction of .singly or doub ly symme tric shapes.
¢,. = I .OCXLRFl1
0,. = 1.5QASLj
and
C,. =1.0
(507.2 -2)
The secti on is organi zed as foll ows: 507. 1 507.2 507.3 507.4 507.5 507.6 507. 7 507 .8
General Pro vision s Members with Unsti ffe ned or Sl iffened Webs Tension Field Action Single Angles Rectangu lar HSS and Box Members Round HSS Weak Ax is Shear in Singly and Doubly Synunctrk Shapes Beams and Gi rders wit h Web Openings
2.
For webs of al l other doubly symmetric shapes and singly symmclJic shapes and channels. except round
HSS, the we b shear coeffi cienl , C1" is determ ined as foll ows: a.
C,. =1.0
b. For 507.1 General Provisions
UujV/Fy
Two method s of calculating shear strength are presented below. The method presented in Sec ti on 507.2 docs not ulili ze the post buckli ng strength of the member (tension field action). The method presented in Section 507 .3 utili zes;
I'
c.
For ,,/Iw
lension fi eld action. The design shear strength, ¢vv,. , and th e all owable shear strength , ~'/fJ... , shall be determi ned. as fo llows.
For all provisions in thi s section except Section 507.2. l a: ~.
= 0.90 (LRFD)
Q,
This secti on applies 10 webs of singly or doubly symmetric members and channels subject to shear in the plane of the web. The nom inal shear strength , V", of unstiffened or stiffened webs, according to the limit stat es of shear yielding and shear buckli ng. is (507.2· 1)
(507.2-4)
hllll'
> 1.37)I<.,.E/1';. 1.51E~.
(507. 2-5)
(h//,.lFy
where = the overall deplh times Ihe web thickness. mm2
The web plate buckling coefficient. k l . , is detennined as follows: a.
507.2. 1 Nomin al Shea r S trength
v" =O.61';.A" .C,.
C,.
A..
=1.67 (ASD)
507.2 M embers wilh Uns tilTened or StilTened Webs
1.
(507. 2-3)
For unstiffened webs with
hit <260.
1<.,. =5cxeept for
the stem of lee shapes where kv ~ 1.2 . b.
For stiffened webs,
5
k,. = 5 + (a/h)2 =5 when
or alh>
a/ h > 3.0
260 ]2 [(lift... )
For we bs of rolled ' ·shaped members with Nalional Siruciural Code of Ihe Philipp ines 6th Edilion Volume 1
5 66
CHAPTEfi S . Steel and Metals
whe re
II"
= dear di stance between transverse st iffeners, lllln. = for rolled shapes, the clear distance bclw·ecn llanges less the fillet or comer radii, mill. = for built -u p welded sections, the clear distance be twccn fla nges, mill . .
= for built -up boiled sccti ons, the distance bctween fastener lines, 111111.
wh ere hi t I\" S 2. 46J
EJFy , o r
strength is less than or equal
members when
3.
2A w /(A lc +A ft »2.S; or
a/"
exceeds 3.0 or 260/("/ ',,}';
4. "/bl, or "/bl' >6.0
= area of compression nange, mm
2
2
All
= a rea of tension flange, I11m
bfi. bff
= wid th of co mpress io n flange , m m
= w idth of te nsion
n ange.
m Ol
III these cases, the no minal shear strength, are
where to
2.
AIr
507.2.2 Transverse Stiffeners s tiffeners
c nd panel s in all membe rs wit h transverse Stiffcn crs;
wherc
= for tces . the overall depth, mm.
Trans vc rse
J.
requ ired
1I 0 t
th e
rcqu ired
shear
the available shear strength
provided ill acco rdance with Section 507 .2. 1 for k I'
::::
5.
V'P shall be
de termined according to the provisions of Section 507.2. 507.3.2 Nominal Shear Streng th with Tension Field Action Wh e n tension field ac ti o n is pe rmitted acc ording to Section 507.3.1, the no mi na! shear strength, VII' with
Tran sverse stiffeners lIsed to devclop the available web shear strength, as provided in Section 507.2.1, shnll have a mom ent of incrtia abollt an axis ill the web center for stiffen er pairs or about the face in contact with the web plate for sin gle
tension field action, accordin g to th e limit state of tensioll
field yielding, shall be
stiffencrs, whi ch shall not be less than at ;'. j, wh ere
2.5 j = - - -nO.5
(al II)'
(507.3· I)
(507.2·6)
2. Transverse stiffene rs arc pennitted to be stopped sha n of thc tc nsion fl a nge, provided bearing is not needed to ;t ran smit a concentrated load or reaction . The weld by wh ic h 1ransvcrse stiffe ne rs are 311ached 10 the web shall be terminalCd lIot less than four ti mes nor more than six limes the web thic kness from the ncar toe to the web-to-nange weld. When si ngle. stiffeners are lISed, they shal l be attached to the compression fl ange. if it consists of a rectangular plate, to resist any uplift tendency due to torsion in the flange. When lateral bracing is altached to a stiffener. or a pair of stiffen ers, these, in tum, shall be COlUlccted to the compression fl ange to transmit 1 percent of the lotal fla nge fo rce, unless the fl ange is co mposed o nl y of
angles. Bolts connecting sti ffeners to the girder web shall be spaced no t more than 305mm on center. l f imenlliHent fillet welds arc lIsed, the clear distance between welds shall not be morc than J 6 times the web thickness nor more Ihan 250 mill .
'II,., > 1.1OJk,.E/ Fy
For
h{C" + I
1'" =0. 6 F y A
(507.3·2) where kl' and
C,. arc as defined in Section 507.2. 1.
507.3.3. Transverse Stiffeners Transverse stiffeners subject to tension field aclion sh ~;i :ncel the requ ire me nts of Section 507 .2 .2 and the !"oHm·,· jog limi tat ions:
(b/t) t $ 0.56 -
2.
A,, >
.s
\
507.3 Tension Ficld Action
507.3.1 Limits on the Use of Tension Field Action Consideration of tension field action is pennitted for fl anged members whe n the web plate is supported on all four sides by flan ges or stiffeners. Consideration of tens ion fi e ld ac ti on is not permitted for:
(-t..
J.
Fyst
~, [O. ISD,JtI".(I-CJ;\ (" - 1 8 t~.J;,()
(507.3-3)
FY,'I where
(bit)"
= the width-thi ckn ess rati o of tile stiffener
Association of Siructural Engineers of the Philippines
CHAPTEH 5
= srcl:i fir.::tl 1', D,
minimum yield stress of the stiffener
material. MPa. ;:; coeffki ent defined in Section 507.2.1 ;:; 1.0 for stiffene rs in pairs
V,.
F,., shall be the Jarger of F
=- 2.4 for si ngl e plate stiffeners ;:; required shear strength at the locati on of the stiffene r, N. = avai lable
shear
v,'/D." (ASD)
slrenglh;
with V , as defined in Section
fii(7)~
.
0.78£
and
V,,, of a si ngle angle
Equat ion
leg shaJl be
(507.2-1)
wi th
f'~r =--3
!
she ar force . mill and k,.:: 1.2
!
507.5 Re ctangular HSS and Box Members
A,<:
D
L".
~
! !
I, i I,
wall gross area of secti on based on design thickness. mm 2. :=; outside diameter, mm. ::: the di stance from maximum to zero shear force, :=;
mm. :=;
The nominal shear strength. \I'll of rectangu lar HSS and box
I
(507.6-2b)
but shall not exceed 0.6F,·
C" = 1.0, AI\' :: bl where b = width of the leg resi sting the
I!
(507.6-2a)
(7)'
The nomi ll~11 shear strength.
j
J.6£
a
507.4 Single Angles lIsi ng
=
or
507.3.2, N.
determined
5·67
where
:: 1.8fof single angel stiffeners \I,
Steel Hnd Metal
mClllbcn; shall be de termined us in g th e provis ions of = 2ht where h for th e width resisting the shear force shall be taken a<; the clear distance between the flanges less th e inside corner rad ius on each Section 507.2.1 with A .•-
side and '", = I and k l • = S. lf the comer radius is not known, It shall be taken as the corresponding outside dimension minus three limes the lhi cluless. 507.6 Round HSS The nominal shear strength, Vn • of rou nd HSS. accord in g to
the limit Slates of shear yi elding and shear buckling, is (507.6-1)
design wall th ickness. equal to 0.93 limes the nominal wall thi ckness for ERW HSS and equal 10 the nominal thickness for SA W HSS, mm .
User Notc: . The shear buckling equations, Equations 507.6-2a and 507:6-2b, will control for Dlt over 100, high strength steels, and long lengths. If the shear strength for standard sections is desired, shear yielding will usually control' .' . 507.7 Weak Axis Shear in Singly and Doubly Symmetric Shapes For singly and doubly symmelric shapes loaded in the weak ax is without torsion, the nominal shear strength, V'I' for each shear resisting element shall be determined using A =b f Equation 507.2-1 and Section 507.2. J(b) with w f! and k" = 1.2
507.8 Bemns and Girders with Web Openings The effect of ali web openings 0 11 the no mina l shear strength of steel and composite beams sha ll be dctennilled. Adequate reinforcement shall be provided when the required strength exceeds the available strength of the member at the opcning.
NaJionaJ Structural Code of the Philippines 6 'h Edition Volume 1
."!!!I .. ,~
5·68
CHAPTER 5 . S leel and Melals
x y
:::: su bscript relati ng symbo l .to stron g axis bendin g :::: subscript relating symbol to weak axis bending
For design cH,;cording to Section 502.3.3 (LRFD ) This secti on addresses members subject 10 ax ial force and flexure abollt one or both axes, wilh or without torsion, and to members subject to torsion o nl y
PI'
The section is organi %;cd as foll ows:
Mr
508.1
Me:
508.2 508.3
!
I
I I
Doubly and Singly Synunctric Members Subject to Flexure and Axial Force Unsymrnctric and Other Members Subjecl 10 Flexure and Axial Force Member.; under Torsion and Combined Torsion, Flexure, Shear ;Uldlor Axial Force
Pc
¢c ¢b
For design according
Pr 508.1 Doubly and S ingly Symmetric Members Subj ect
PI'
to Flexure and Axial Force
M,
508.1.1 Doubly and Singly Symmet ric Members in
Me
Flexure and Compression The interaction of flexure and compress ion in doubly symmetri c members and singly symmetri c members for which 0.1::;; (! )Ie / I y ) ~ 0.9, that are con strained to bend aboul a geometric axis (x andlor y) shall be limiled by Equations 508. 1· 1a and 508. I ·1 b, where I yr the momenl of in ertia about the
y~axjs
referred to the compression flange,
mm4. USer. I)lQI~; .SectiQI.15!J8Q,ispcPnitte
= rcquired .txial !,;omprcssivc slrength lIsing U?FD load combinations, N . :::: design
Dc fl.b
10
Seclion 502.3.4 (ASD)
:::: required axial comp ressive strength usin g ASD load combinations, N. :::: P,IQI.::::a lJ owable axia l comprcssive strength, dctermincd in accordance with section 505, N, :::: required flexural strcngth using ASD load co mbin at ions, N-mm , =MnIQb:::alJowab le flexural strength determined in accordance wi th section 506, N· mm. = safety factor for compression:::: ) .67 = safety factor fo r flexure = 1.67
508.1,2 Doubly and Singly Symmetric M e mb er s in Flexurc and Tension The interaction of flexure ~U1 d lension in doubly synunctric members and singly symmetric members constrained to bend about a geometric axis (x and/or y) shall be li mited by Equalions 508. I . I a and 508.1·1 b, where
For design accord ing to Seclion 502.3.3 (LRFD) P, (508.1·1a)
Pc Mr
P
2. For - ' < 0.2
Me
Pc
!5...+(M" + Mo·JS I.Q 2Pr Mn Mcy
(508. 1· I b)
where
"'/I
= required tensile strength using LRFD load combi nalions, N. = ¢,Pn::::design tensil e stren gth, determined in accordance with Section 504.2, N. = required fl exural strength lIsing LRPD load combinat ions, N~mm. :::: ¢bM,,::::design flexura l st re ngth determined ill acc ordance with sectIon 506, N ~ll1ll1, = resistance fact or for tension (see Secti on 504.2) : : resistance faclor for flexure:::: 0.90
For do ub ly sy mm et ric members, C b in section 506 may :::: required axial compressive strength, N, ;:: avai lable axial compressive strength, N. = required flexural strength, N·mm. = available flexu ral strength, N·mm.
be increased by
p I +_11
for axial tension that acts
p(!)'
concurrently with flexure, where
Association of Structural Engineers of the Philippines
CHAPTER 5
Steel and Metal
5·69
where
p.... M.o).
For design according to Sec tion 502.3.4 (ASD) 1'1'
1',
M, M,.
n, 0"
::: req uired t cn~ il c strengt h us ing AS!) load combinatio ns, N. = P,I!2 I =a ll owable te nsil e stre ngth , dete rmined in accorda nce wi th Sec tion 504.2. N. ::: requi red fl exural stre ngt h us ing ASD load combinations, N·mm. = Mn/Db=allowable flexuraJ strength determined in accordance with section 506, N-mm. ::: safelY factor for tcnsion (see Section 504.2) = safety factor for nexure =:: 1.67
= available compressive sirength out of the plane of bending. N. = available Oexural -torsional strength for strung axis n cxurc determincd from sec tion 506. N· mOl.
If bending occ urs only abou t th e weak axi ~, the momen t ra ti o in Equa
Flexure and Axial Force
rol' doubly symmetric members, C b in section 506 may be
1+ 1.5P'1
incrcased by \
for axial
ten sion that acts
Pry
This section addresses the interaction of flexure and axial stress (or shapes not covered in Section 508.1. It is permitted to use the provisions of this Section for any shape in lieu of the provisions of Section 50S. I .
(508.2· 1)
concu rre ntl y with fl exure where
A morc detailed analysis of the inte raction of fl exure and tensio n is permj tted in lieu of Eq uations 508.1- 1a and 50B.I - Ib.
where
fa
MPa.
Fo 508.1.3 Do ubl y Sy mme tric M e mb er s in S in gle Axis
F lex ure and Compression For doubly symmetric members in flex.ure .Uld compression with moments primarily in one plane, it is perm.issible to consider the two independent limit SLates, in-plane instability and out-oC-plane buckling or flexural ·torsiollal buckling, separately in lieu of the combined approach provided in Section 50B. I. I.
I.
2.
= requ ired axial stress at the point of consideration, = available axial stress at the point of consideration, MPa.
fb ... JlJ:
= required flexura l stress at the point of
conside ration, MPa. Fb. .~Fb~ = available flexural stress at the point of I\'
z
considerat ion, MPa. = sUbscripl relating symbol to major principal axis bending = subscript relating symbol to minor principal axis bending
For the limit stale of in·p lane instability, Equations
50B.1.I shall be used with Pc, M c. and Me determined
For design according to Section 502.3.3 (LRFD)
in the plane of bending.
/,
For the limit state of out-of-plane buc kling
F,
-;!-+ P (--' M J' ~ l .O M co
(508.1-2)
0:
fb ....fb ~
Fb ...., Fb1
(lc
= req uired
axial st ress usin g LRFD load combin at ions. MPa. =desig n axia l s tress, determined in for accordance with sec t ion 505 compression or Section 504.2 for tension,MPa . = required Oexural Slress at Ihe specific locat ion in the cross sec ti on using LRFD load combinations. MPa. = ;bMnIS=design flexural s tress determined in accordance with s ection 506, MPa . Use the section modulus for the spec ifi c location in the cross section and consider the sign of the stress.
= res istance factor for compression := 0.90
National S tructural Code of the P hilippines 6'h Edition Volume 1
5-70
¢I
¢,,,
!
1
CHAPTER 5 - Sleel and MOla is
;::; resistance faclOr for tension (Section 504 .2) =rcsist
. F
Fa
fb ..Jbt
;: required
axial
stress
us ing
ASD
lUcid
co mbinations. MPa = FrIDt' ::: ililowable axial stress determined in :'lcconJancc with section 505 for compression, or Section 504.2 for ten s ion, MPa _ ;::; required flexural stress at the specific locati on in the cross section using ASD load combinations.
Mr._
rb .... Fbl ;
I
I!
Qr
Q, Q"
;::;
M" / Q~' = allowable flexural slress detcnnincd in
accordance with section 506, MPa. Use the section modulus for the specific location in the cross section and consider lhe sign of lhe stress. ;:; safety factor for compression = ).67 =safey faclor for tension (Section S04 _2) ;::; safely. factor for flexure;::; 1.67
Equation 508.2-1 shall be evaluated using [he principal bending axes by considering the sense of the fl ex ural stresses at the cri tical points of the cross section. The nexura l terms are either added to or subtracted from the axia l tcrm as appropriate. When the axial force is compression. second order effects shall be included according to the provisions of secti on 503.A more detailed analysis of the imeraction of nexure and tension is-pcnniUed in lieu of Equation 508 .2- J.
(508.3·2b)
but shall not exceed 0.6F)" where
L D I.
:=; length of the member, 111111 . = ou tside diameter, mill.
For rcctangular !iSS
a_ For h/T$ 2A5JEf F, (508.3·3) h . For 2ASfE/ F,. < II/T S 3-07JEri~
F" = 0_6F!. (2.4SJEj Fy
c.
For 3_07
Q r =L67(ASD)
The nomina l torsi ona l strength. Til according to th e limit states of torsional yieldin g and torsional buckling is: I
(508_3· J)
Fer
JE/ Fy < hiT S 260
User, Note! - 1"1!e torsional
torsional strength. Tn/fl r •for round and rectangular HSS sha ll be detennined as follows:
C
(50B.3-4)
(SOB.3 -S )
.she~r . con~\lIu~
con_se!'Y~~v~!y t.I\k~/l-.aS: .. "" -
The de sign torsional strength , rpr~,. and (he allowable
where
)/(h/T)
=OASSn' E/(h/T)'
F"
Flexure, Shear and/or Axial Force 50S.3.1 Torsional Strength of Round and Rectangular HSS
2,,)
and
50S.3 Members under Torsion and Combin ed Torsion,
(ir =0.90 (LRFD)
(50~ . 3
" fEe:):
For design "ccording 10 Seclion S02.3.4 (ASD)
In
1.23E =--.----
-
. '.,. ",' -·itf.p ..:. tf,.t C
Foq round HSS :
2
..
::
For' l'&WigliJaf HS~-:;
-.; 2;;).{}j.'. ,Xif -i-Xi-4·W:.."jt'.' 508 _3.2 HSS Subject to Co mbin ed Torsion, Shear,
·Flexure and Axhll Forct' When the requi red torsional strength. 7~. is less thall 01 equal to 20 pcrcellt of the avai labl e torsional strength.
Tc .the interaction o f tors ion, shear, nexure and/or axial is the HSS torsional constant
force for HSS shall be determ ined by Section SOB_I and Ole
shall be determined as follows:
torsional effects shall be neglected . When exceeds T"
1_ For round HSS, Fa shall be the larger of
percent of
20
Te the interaction of torsion. shear, flexure and/or J
axia l force shall be limited by
Association of S tructura l Engineers of the Philippines
CHAPT En S
(50X.3 -6 )
For design according 10 Seclion 502.3.3 (LRFD)
= required
axial
strength
using
LRFD
load
M,
combinations, N. = ,pPII • design tensile or compressive strength in accordance with section 504 or 505. N. == required flexural strength using LRPD load
M,
==
combinations. N-mm. ¢bMIl,design flexural strength in accordance
\I,
with section 506, N-Illm. : :;: required shear strength combinations, N.
\'e
= design
P,.
5-11
508.3.3 Slrength of Non-HSS Members under Torsion and Combined Stress
The design torsional slrellglll.lPTI·~1' and (he .lIlowablc
where
Pr
Steel and Metal
using
LRFD
load
IOrsional strength. I~JQT' for llon·HSS members sha ll be the !owest value obtnined according to the limit states or yield ing un der norm al stress, shear yieldillg under shear stress, or buckling, de termin ed ;]s follows:
tPr =O.90(LRFD) 1.
fiT
=1.67 (ASD)
For the limi t stale of yielding under normal stress (508.3-7)
2.
For the limit state of shear yie lding under shear stress
F" = O.6Fy
shear strength ill accordance wi th
(508.3-8)
seclion 507, N.
= required
T,
torsional strength using LRFD load combinations. N-Il1:m. : :;: design torsional strength in accordance with Section 508.3 . 1. N·mm.
For design according 10 Seclion 502.3.4 (AS D) P,
Pc
: :;: required axial strength using ASD load combinations, N. = P,1D, allowable ten sile o r compressive strength
M,
in accordance with section 504 or 505, N. = required flexural strengtll using ASD load
Me V,
3.
or the lim it Slate of buckling
(508.3-9)
where ::: buckling stress for the section as determined by analysis, MPa. Some constrained local yielding is permitted adjacent to areas that remain elastic.
combinations detemlined in accordance with Seclion 502.5, N-mm. ::: M,/D1" allowable Oexural strength In accordance with section 506, N~l1lm. ::: required shear strength llsing ASD load
combinations, N. Vi'
T, 1~
::: allowable shear strength in accordance with seclion 507, N. ::: required torsional strength using ASD load combinations, N-mm. :::: T,/DT allowable torsional strength in accordance with Section 508.3. 1, N~mm .
National S lruclural Code 01 the Philippines 6 'h Edilion Volume 1
5· 72
CHAPTER 5 . Sicel ilflU Metals
Thl' s tr~ss' ~ l r a ili rcl;Hi ollsh ips for stccl
l'OIKr~t l'
This sc<.: tion ac.h.Jrcsxes composite columns com posed or roll ed or buill-up struclUral steel shapes or HSS. and strucltlral co ncrete acting togclher. and stcel heams supp0l1ing a reinforced conc rete slab so intcrconn ected that the beams .1I1d the slab tiCI toge ther to resist hcndillg. Silllple and cOJ}li'lu(}uS composilc beams with shcar connectors and concrctc-encased bemns. constnti;ted with or wil hout temporary shores. arc included . The scction is organized 509. 1 509.2 509.3 509.4 509 .5
,IS
User Note: The Slrain compalibility method should be us:e.i" 10 determine nominal strength for irregular sections -a nd for cases where tbe "eel dO eS not exhibit e)a,'to-pJW).~ behavior. General guidelines for the slrain-compatibiUfh tnedlOd fO'r encased columns are given 'ip 'AISC De~rg-Ir Guide6 alld ACl31 8 Scclions 10.2 and 10.3. '?("
509.1. 2 Material Limitatiolls Concrete and ~ I cd reinforc ing bars in c.:()lllposi{~ sys tems 511<111 be subject \0 the fo llowi ng lilll ililliolls.
follows:
General Provisions Axial Members Flex ural Members Combined Axial Force mnl Flexure Special Cases
509. 1 General IJrovisiolls
In dctennining load effec ts in mcmbers and co nnec ti ons of'
For the plastic stress distribution method. the nominal strength shall be compu ted ass uming th at steel components ha ve reached a stress of F \' in either tension or co mpression and concrete co mpon ent s ill co mpression have rcac hed a stress of 0. 85/; For roun d HSS fillcd w ith concrete, it stress of' 0.95/c· is pCI111illed to be used for concrete components in uniform compression to account ror the errects of concrete confi nemcnt. 509 .1.1b Strain-Compatibilit y Method For the strain compatibility mClhod, a linecu' distribut ion or strains across the section shan be assumed . with th e maximulIl concrete co mpressive strain cqual 10 0.003
I.
For the determi nation of the availablc strength. COnCrete shall have:1 com pressive stre ngt h f,~ ornot less than 21
MPa nor morc than 70 MP" for normal weight concrete and not le.'\ s th an 21 MP" nor more than 42 MP" for light weight cOI1<.:rcte. User Not.e:. Higher strength cqncrete materials lTliIY be us"q. for stiffness calculations but may not be relied ,Jlp~.n ·JiiF strength calculations unless juslified by testing or analysis.
2. The specified minimum yield stress or s tru c tural stecl a nd reinforcing bars lIsed in calculating the strength of a compositc colum n shall not exceed 525 MPa. Hi ghcr material strengths are permi llcd when their use is justified by testi ng or analysis.
User Note: AdditiolHll reinforced concrete materia'l~ limitations are specified in Chapler4. 509.1.3 Shear Connectors Shea r connectors shall be headed sleel studs not less than four stud diameters in length after installation, or h ot ~rolkd steel channels. Shear stud design values shall be taken as p. r Secti ons 509.2. 1g and 509.3.2d (2). SlUd connectors sh;.; i conform to the requirements of Section 50 1.3.6. Cham:d connectors sh
509.2. 1 Encased Composi te Col umns 509.2.1.1. Limitations To qualify as an encased co mposite col u111 11, lhe foJ! ;~~';;; ..: limitatio ns slwll be met:
A
Association of Structural Engineers o f tile Philippines
I.
The cross-seetio/wl area of' the steel core shall cornprisc
where
aI least I percent of rhe total composite cross section.
2.
Concrete cnr,lsc mc nl
or
= area of th e steel section, 111 m2
= are a of concrete. mm 2• = area o f co ntinuoll s reinforcing
th e steel core shall be
reinforced with cOlltinuous longiludilll1l bars illld latent! lics or spirals . The minimum transverse reinforcement shall be at lcast 6 mm 2 per mm of lic spa ci ng .
3.
The minimulll rcillforccmcn(
ratio
longitIJdinal reinforcing, P.I"/"' shall
PSr' is
for continuoll s
be 0.004. where
bars, mm 2 :::; modulus of elasticity of cOll crelc
( 004 3",:5 f:.~
/'.
given by:
F,.
,1"
P.1·, - 1\
(509.2-1)
== modulu s of elasti city of slee! :::; 2 10 MPa.
= specified compressive strength of concrete, MP,. = specified mi nim um yield stre ss of steel section. MP •. :=; specified minimum yield stress of reinforcing bars. MPa . = mo ment o f in e rl ia o f th e co ncr e te
.
wh ere
A'i Ag
sec ti o n , mill
::; area of continuQu s reinforcing bars, 111m2 ;; gross CIrca ofcomposilc member, mm 2
509.2.1.1 b Compressive Strength
I, I" K
L
The design compressive sirenglh , ¢cf!p and all owabl e
P,JQ c ' for axially loaded encased
compressive strength,
composite columns shall be determi ned for the limit state
of fle xural buckling based on column slenderness as follows:
When p,
?
moment of inerti a of steel shape, mm-l 4 moment of inerti a of reinforcing bars, mm =thc effective length factor determined in accorda nce with Secti on 502 = laterall y unbraced length of the member, mill = wei ght of concrete per un it volume (90S we S I 55/bs/ filo, 1500S we S 2500kg/m l ) :=; :=;
n., =2.00 (ASD)
:;:: effective stiffness of composi te section.
N_mm 2 EJ,jJ = E, I, +0.5E, I" +C,Eel e (5 09.2-6)
0.44 p ,
-[
P" - Po 0.658
2.
,
where £/~ff
jZMPa )
(~l]
where (50 9. 2-2)
When Pe <0,44Po
P" =0.877p"
CI ~ O . I +2 (
A,
A(' + A ,
) ~ O .3
(509.2-7)
509.2.1.1 c Tensile Strength (509.2-3 )
The design tensile slrength,
4>1 P'll and
allowable tensile
strength , Pn / Q./ I for encas ed composite columns shall be determined for the limit state of yielding as
where
(509.2-4)
(509.2-5)
(509.2 -8) 1/>,
=0.90(LRFD)
12, = 1.67 (ASD)
509.2.1.1<1 ShclIr Strength The avail3ble shear strength shall be cal culat ed based on eithcr the shear stre ngth of the steel secti o n alone as specified in Secti on 507 plus the shear strcngth provided by ti c reinforcement, if present, or the shear strength of the reinforced concrete portion alone.
1h
National Structural Code of the Philippines 6 Edition Volume 1
5- 74
CHAPTE n 5: - Swel and Melals
User Note:. The nominal shear strength of tie reimfprcel1lQQt rnay~e,4"t"'iJ4jf),w~iflt.f4~ii;;jiii~; ~~~\t of tie reinforgernent, dis ' the-'effective .; depth of the concrete ' "seetion,'" and . 'so' is':" 'ih6' ,·. s~iidrig ::, of' ·the · . tie reinforcement. The ' shear dlplidt)f of reinforCeil ' concrete may be determined according to ACr 318, Chapter 11 . 509.2.1.1 r Load Transfer Loads applied to ilx ially loaded ellc
When (he extcrnal force i s applied directly (o the stee! section, shear connectors shall be provided to transfer th e required shcar force, V', as follows:
1" =V(I - AJ F.).
/p ) (I
encased composite column above an d below th e IO;JfI tnm sfcr region. The ma ximum connector spacing :-!1:1!1 h , ~ 405111111. Co nnectors (0 transfe r ax ial IO~ld shall be placed on :\~ k:!:.;! two faces of the steel shape in a configuratioJl symn](.'lric,d about the steel shape axes. !~ . the composite cross section is built up from Iwn or morc encased stcel shapes, the shapes s 1 ~:l !l i ... interconnected with lacing, tic plates, ballcn pl
509.2. L 1g Strength of Stud Shear Connectors The nominal strength of one slUd shear connector el1l h ~{i ·._ ; c( : in solid conc rete is:
Q, =05As<);;:t~
where :::; required shear force introduced 10 column, N. :::; arca of steel cross sec ti on, mill:! :::; nominal axial compressive strength without consideration of length effects, N. 2.
Wh en thc external force is app li ed direcUy to thc concrete encasement. shear co nn cctorS shall lx~ provided to transfer the required shear fo rce, V', as follows: (509.2- 10)
3.
When load is applied to the concrete of an encased composite colum n by direct bearing the desig.n bearing stren gt h, ¢lnPp' and tile allowable bearing st rength, pp /fl./J' of the co ncrete shal l be:
¢Ii = 0,65 (LRF~
Q Il =2JI(ASD)
F"
509.2.2 Filled Composite Columns 509.2.23 Limitalions To qualify as a fill ed composite column the fo!1 o\'.. -:: limitations shall be rnet : The crossM scctional area of the steel /iSS shall least 1 percenl of
509.2.1 . Jf Detailing Requirements 1\( Icas t four continuo us iongilUdinal re infnrcing ha rs shall be lIsed in encased co mpos it (' columns . Transve rs . . rcinforcemcllI s hall bc spaced at the slll al lc:st or 16 longi llidill al hal" diameters. 4g tic btu· di;UllCICI"S or 0.5 times lhe leasl dimcnsion of the co mposite sec ti on. Tht e!lcasemcnt shall pro vide at IcaM 38 mill of' clear cover to thc re info rcing steel.
Shear con ncc tors :-oha ll be provided 10 Irall sfc r th e required shea r force specified in Sect ion 509.2 . Ie. The shear connectors shall be distribut ed along th e length of the member at leas t a distance or 2.5 times the depth of the
comp; ~ ~,~ :H
The low l composi tc cross secli on.
2. The maxim um bit rati o [or a rec tangu lar I-ISS \ a compositc column sha!1 be cqlwi
, j
2.26J E/ F.r .Hi gher ratiO,S are permitted whe~ lISC
:::; louded area of concrete, mm:!
(5092 i 2)
:::: cross Mscc li onal area of stud shear co nnetl or, liH,,: · :::; specified minimum tensile strength of it !i 1\Jd shear connec tor, MPa.
AJC
where An
AJ;,
whe re
I. (509.2-1 1)
$
1.
is justified by tes ting or analysis .
The maxim um D/, ratio for a rollnd !i SS fii! \" l co nc rete shall he O. I 5 E/ Fy . Highr.r ra:i, permilled whe n th eir use is j ustifil!d by tlIlillysis.
.,'.
!l:
~,;.
509.2.21> Compn.'ss h 'c St reng th The dc."igll (':olllprcs~ivc strength, tPl.I~ I ' tUld il li\i\\,tblc
co mpressive st rcngth, Pit / 0.1"' for ax ially IO:H[": (:omposiic colum ns shall be det ermin ed for thc.li m:l . ..:..' ...,1 ncx ulIll buckling based on Section 509.2. Ih '. ;1i.followi ng modificcltions:
Association of StructlJral Ennineers of the Phil ippines
(51}) ..' i ,j
CHAP H . n !j
C2
::::: 0.85 I'm reclangular sec ti ons ;l lld 0.95 for circular sccli om;
(509.2·14 )
c, =06+ 1-~)$0.9 .
lAj"+A.\.
it distance or 2 .5 limes the width of a rectangu lar HSS or 2.5 ti mes the d iml1CICr pf a rotlnd HSS hoth abo ve ilnd below the load tnill sfc r region . '111C maximu m connect or spacing Shllll he 40SIllJll . .
member at least
509.3 Fltxural Mcmh crs 509.3.1 General
The design tensile strength. $(~" and allowable te ns ile
P" jn ,. for
5· 7!,
(5092 · 15)
509.2 .2c. Tensile Strength
strength,
Steel and Melal
fi ll ed com posite columns shall be
509.3. 1:1 Effective Width The effective width of (he conc rete slab is the sum of the effective widths for each side of the beam centerline, each
of whic h shall
nOl
exceed:
dClCnnincd for the limit siale of yield in g as:
I.
n, = 167 (ASD)
¢, =O.90(LRF!i S09.2.2d Shear Strength
The available shear st rength shall be c
User Note: The shear strength of reinforced concrete may be determined by AC13 18, Chapter 11. 509.2.2e Load Transfer
Loads applied to filled composite columns shall be transferred between the steel and concrele.. Wh en th e ex ternal force is applied either to the steel section or to the concrete infill, tran sfer of force from the steel sec tion to the concrete co re is required from direct bond interaction, shear connecti on or direct beari ng. The force transfer mechan ism prov iding the largest nominal strength may be used. Th ese force transfer mechanisms shall not be superimposed. When load is applied to th e concrete of an encased or fi lled compo!)ite column by direct bearing th e design bearing strength, ¢' 8 Pf!' an d the allowable bearing strength,
p"ln.n of th e co ncrete shall be:
one-eighth of the beam span , center-Io-cen ler of
SUPPOl1s:
(509.2. 16)
2.
one-half th e distance to th e cente rlin e of the adjacent beam : or
3.
the di stClllcC to the edge of the shib .
509.3. 1 b Shear Strength The avai lablc shear strength of co mposite bC;Jllls wi th shear co nnectors shall be determined based upon the properties of th e steel sect ion alon e in (lccordance with Section 507 . The available shear st rength of concrete-encased and fill ed com posite members shall be deterrn ined based upon th e properties of the :){ccl sec tion alone in accordance with Section 507 or based upon the properties of the concrete and longi LUdi nal stcci rei nforcement. User Note: Thc shear strength of the reinforced concrete may be detemlined in accordance with ACI 318. Chapter 11. 509.3.1c S trength During Cons truction Whe n temporary shores are not used du ring constructi on, the steel sec tion al one shall have adequate strength to support all loads app lied prior LO the concrete attaini ng 7S
f;
pe rcent of its specified strength .The avail able llexural strength of the steel sec ti on shall be determined according to Section 506. 509.3 .2 Strength
(509.2· 17)
0." ~ 23 I(ASD) where Au
= lhe loaded area, 111m2
Shear
of
Co mpo s ite
Beams
with
Connectors
50 9.3.2" Posi tive Flexura l Strength
The desi gn positive fl ex ural strength, ~bMI1 ' and th e all owable positive fl exu ral strength, M,)D.1pshali be dete rmined fo r the limit slale of yielding as foll o ws:
509.2.2f Detailing Requirements
Where required, shear connectors transferring the required s hear force shall be distributed along the length of the th
National Structura l Code of the Philippines 6 Edition Volume 1
5·7G
CHAPTE n 5 . Steel and Metals
M" shall be dctcnnined from the plastic strl!S~ di stribution
wi th welded slUd sheilI' connectors It) mill or less in diamcter (A WS D 1. 1). SlUd~ shall be welded either through the deck or dircl: tly 10 the steel l:n>ss sectioll. St ud shear COllncl:lUrs, 'Ifler inslall;uiun. shall cxtend 110{ less
Oil Ihe: composite secti on for the limit slate of yie ld ing
(plastic
IIlOIllCnt).
than 38 IllI11 above the lOp of the steel de ck (!Ild there shall be at leasl 13 mill of concrete COver above the (OP of the installed slluls.
User Nole: All current ASTM A6 W. Sand HP shapes satisfy the limit given In Section 509.3 .2.(a) for Fy $
'"
345 MP •. 2. For 1>/1 ..
c.
> 3.76~Ej F,..
,]0{
Ic.ss
th an 50 mill.
Mil shall be dc te rmined From the ~lIpcrposi ( io l1 of elastic stresses, considering lhe effects of shori ng. for thc limit sHlte of yieldi ng (yield moment).
d.
Steel deck shall be illlc horcd to all suppol1i ng members at a spacing 1101 10 exceed 460 111 Ill . Such anchorage shall be provided by !>Iud connecto rs, a co mbinalion of stud conneclors and arc spot (p uddl e) we lds, or other devices specified by the designer.
2.
Deck Ribs Oriented Perpendicul;lf 10 Steel Beam Concrete below the top of the steel deck shal! be neglected in dc termining composi te section propcI1ics and ill calculating At, for deck ri bs ori e nted pef¥ pendicular to th e stecl beams.
3.
Deck Ribs Oriented Parall el to Steel Beam Concrete below the top of the steel deck may be included in determining composite section properties and shall be included in calculating A~ .
4.
Formed steel deck ri bs ovcr supp orting beams may be split longitudinally and separated to form a concrete
509.3.2b Negative Flexurnl Strength The design nega tive ncxural st rength, (AM 1/' and the
Mn /n" ,
allowahle nega tive flexura l st reng th, sha ll be determined for the steel secti on alone, in accordance with th e requircments of Section 506. Allernatively, the available negative flexural strengt h shal! be dctermined from the plastic stress di stributi on 011 th e compos ite section, for the limit s13te of yi elding (plastic moment ), with
1/>" = 0.90 (LRFd)
haunch.
provided that :
1.
Thc slab thickness above the steel deck shall be
The steel beam is compaci and is Rdeq ual ely bmced according 10 Secrion 506.
When the nominal depth of steel deck is 38 mill or greater,
2.
Shear connectors connect the slab ( 0 the steel beam in the negative 1Il0 lllc nl region.
the averagc width, HI r of thc sUPP0rled haunch or rib shall be nOI less than 50 mill for the first stud in the transverse row plus four stud diameters for each add itional stud.
3.
The slab reinforcement parallcl (Q the steel beam, within the effecti ve width of the slab, is properly developed.
509.3.2d. Shear Connectors
509.3.2c Strength of Formed Sleel Deck
1.
Composile
Beams with
General Tile availab le ncx ural strength of composite cOIl~tl1lction consis ting of concrete slabs on formed steel deck connectcd to steel beams shall bc dctermined by tlie applicable. POl1i oilS of Seeliol l 509.3.2a and 509.3.2b, wil li the following requi rements:
l'I.
shea r force, V',between tile point of maximum positive momen t and the point of zero momenl fihaJJ be taken as the lowest value according to the li mi t states of concrete cl1lshing. te ns ile yield ing of the steel sectioll. or strength of the shc:c:' COllllcctors: u.
Conc rete crushing
This section is applicable to decks with nominal rib height not greater than 75 mill . The average 'v.'idlh of concrete rib or haunch, w ,. shall be nol less than 50 mill, but shall not be taken in calculations as morc than the minimum clear width near the top of the steel deck.
b.
1. Load Transfer for Positive Momen t The entire horizontal shear at the interface between the steel bea m and the concrete slab shall be .ssumed to be transferred by shear connectors, except for concrc t c~encased beams as defined in Secti on 509.3.3. For composite action with concrete subject to nexural compression, the total horizon tal
The co ncrete slab shall be connected to the stc-.el beam
(509.3- 1a) b.
Tensile yielding of th e steel sectio n (509.3-lb)
c.
Strength of shear conllectors
Association of Structural Engineers of the Pllilippines
CHAPTEli 5
(509J-Ic)
where A,.
: ; - arca III III 2
A, EQ"
or concrete s lab within effecti ve widt h •
= area of .'lIce! cross section, 11)111:.' : ; - sum of nominal strengths of shear connectors between the point of maximum positi ve 11lOlllcnt
and the point of zero moment, N. 2. In
Load Tran s fer for Negative Moment continuous composite beams where
longiludin:ll
/II'
reinforcing steel in the negati ve IllOlllent regions is cons idered to act compositely with the steel beam, the total horizontal shear force between the pOint of maximum negative moment and the point of zero moment shall be taken as the lower value according to the limit states of yielding of the steel reinforcement in the slab, or strength of the shear connectors: a.
Fyr
steel shape iJnd the rati o of the average rib width to rib depth ~ 1.5 :; 0.85; (a) for two studs welded in a steel deck rib with the deck oriented perpendicular (0 the steel shape ; (b) for one ' IUd welded through steel deck with th e deck oriented parallel to the steel shape and the ratio of the average rib width to rib depth < 1.5 :::: 0.7 for three or more studs welded in a steel deck rib ':"ilh the deck oriented perpendicular to the steel shape 1.0 for studs we lded directly to the stee l shape (in other words, not through steel deck or sheet ) and having a haunch delaiJ with not morc lhan 50 percent of the lOp flange covered by deck or sheet stccl closures 0 .75; (a) for studs welded in a composite slab with the deck oriented perpendicular to the beam
=
and
(509.3-2a)
= area of adequHtely developed lon gitudina l reinforci ng stee l within the effective width of the 2 concrete slab, mm = specified minimum yield stress oftlle reinforcing Sleel, MPa.
emid-hl
(509 .3-2b) We
distance from the edge of stud shank to the steel deck web. mea. mea.surcd at mjd~height of the deck rib. and in the load bearing directi on of the stud (in other words, in the direction of maximum moment for a simply supported beam). mm. = weight of concrete per unit volume (1500 ~ w e ::: 2500kg/m'. ;::;
3. Strenglh of Stud Shear Connec tors The nominal strength of one slUd shear connector embedded in solid concrete or in a composi te slab is
~RgRpAscl'~,
(509.3-3)
where
Asc
= cross~scctional area of stud shear co nn ector 2 ' '
Ec
= modulus of e lasti city of concrete ::::
n1l11
( 0043",~5 J/, MPa) FII
= specifi ed minimulll tensile streng th o f a stud
IIg
= 1.0; (a) for one stud welded in a steel deck rib with
2:2io. (50 mm); (b) for studs
emid-ht ~ in. (50 mm)
(~""d./JI
a. Strength of shear connectors
Q n ;:::;O.5A sc Jf;E c
i"I
welded through steel deck, or steel sheet used as girder filler material, and embedded in a com posite slab with th e deck oriented parallcl10 the beam :::: 0.6 for studs welded in a composite slab with deck oriented perpendicular to the beam and
where A,
:j
=
Tensile yield ing of the slab reinforcement
V ' ::;;- A"P,I'"
Steel and Metal
shear connector, MPa. the deck oriented perpendicular to the s teel shape; (b) for any number of studs welded in a row directly to the steel s hape; (c) for allY number of studs welded in a row Ulrough steel deck with the deck oriented parallel to the National Struclural Code of Ihe f'11i1ippin es 6'" Edition Volume 1
., 5-78
CHAPTEH 5 - Sleel and MCIaIS
horizontal shcilr force as determined in SC((iOllS 509.).211( I ) and 509.1.2t1(2) dividcd by the nominal strength of nIH: ~hear l'onncclOr as determined from Section 509.3.2d(1) or
Section 509.1.2d(4). 7. Shear Con nector Place men t Hnd Spacing Shea r connectors required on each side or th e poi nt of nwx imum bending moment, po~ilive or ncglllive, shall be d i~ triblltcd uniforml y between that point and the adjacent points' of zero moment, unlc~s ()thcrwisc specified . However, the number or shear connec tors placed he tween any concelHfated load a nd the nearest point of zero moment sl1
conneClOrs shall
have at Icast 25 mill of lateral the ribs of formcd steel decks. The diameter of studs shall nol be greatcr than 2.5 limes the thickness of the nange 10 which they arc welded. unless loemed over Ihe wcb. The minimum center-to-center spacing of slUd COllncclOrs shall be six diamcters along the longitudinal axis of the support ing co mposite beam and rour diameters transvcrse to the 1011 gi llldinal axis of the supporting composite beam, cxcept that withi n the ribs of form cd steel dec ks oriented perpendicular 10 the steel bea m the minimum cen ter-la-center spacing shall be four diameters in any direction. The maximum cc ntC.f-lO-cc nter spacing of shear connectors shall not exceed eight limcs the total slab thi ckncss . concrete cover, except ror conneCLOrs installed
~
;0~~~~~'~~;~~~1~Lr~z~~!;!~l~~~~~~~;~:c~~s~hear to the
of
maybe
such as
• ~. fPiili,!1 t
efflid_1r1
5. Strength or Channel Shear Connectors The nominal strength of one channel shear connector slab is embedded ill a solid
concrete
503.3 Flexural Strength of Concrete· Encased and Filled Members Thc nominal flexural stren gth of concretc-cncased and filled following membcrs ~ shall be dctcnni ned using onc of methods;
the
a.
TI1C superposition of clastic st resses on the composite section, conSidcri ng thc effects of shori ng, for the limit stale of yieldin g (yield lllo l11enl), where
where =:::
1ft, =O.90(LRF~
flange thi ckness of channel shear connector, Jl1m . chann el shea r con nector,
= web thi c kne ss of mm .
L,.
in
b.
The plastic stress distribution on the steel section aIOl)(:, for thc limit slale of yielding (p lasti c moment), where
c.
If shear connectors are provided and the concretc
= length of channel shear conneClOr, mill.
l 1lc strength of the channel shear COllllcctor shall be developed by wclding ule channel (0 the beam flange for a force equal to Q". considering eccentricity on the connector.
6. Required Number of Shear Connectors The nu mber of shear connectors required between the section of max imum bending moment, positi ve or negative, and Ihe adjacen t secti on of zero moment shall be equal to th e
mects the requirements of Section 509.1.2. Ihe nominai flexural strength sha1l be computcd based IIj}vll thc plastic stress distribution on the composi te section or from thc strain-compatibility method, where
fA =O.85(LRF~
Associa lion of Struclural Engineers of Ihe Pililippine s
CHApn~fi
50~.4
5
Steel and Metal
[)·l9
Combined Axial Fonc and Flexure
The interaction be(ween axial forces and flcxure in composite mcmbers shall account for stJbility as required by Sec(ion 503. The design compressive strength. ¢J~I' and
allowable compressive strength, I~Jflc' and the design flexural strength,
Mjflt"
¢hMn! and allowable flexural strength,
arc determined as follows:
¢,. = 0.75 (LRFD)
11, =0.90(LRFq I.
2.
0., =2.00(ASq
This Section addresses connecting clements, connectors, and the affected clements of the connected members not subject to fatigue loads. The Section is organized as follows: 510.1
510.2
0." = 1.67 (ASq
The nominal strength of the cross section of a composite member subjected to combined axial compression and flexure shall be determined using either the plastic stress distribution method or the strain-compatibility method. To account for the influence of length effects on the axial strength of the member, the nominal axial strength of the member shall be determined by Section 509.2 with Po taken as the nominal axial strength of the cross section determined in Section 509.4 (1) above.
510.3 510.4
510.5 510.6
510.7 510.8 510.9 510.10
General Provisions Welds Bolts and Threaded Parts Affected Elements of Members and Connecting Elements Fillers Splices Bearing Strength Column Bases and Bearing on Concrete Anchor Rods and Embedments Flanges and Webs with Concentrated Forces
509.5 Special Cases When composite construction docs not confonn to the requirements of Section 509.1 through Section 509.4, the strength of shear connectors and details of construction shall bc established by tcsting.
510.1 General Provisions 510.1.1 Design Basis The design strength,
#?", and
the allowable strength
R'l / flof connections shall be determined in accordance with the provisions of this Section and the provisions of Section 502 .
The required strength of the connections shall be detemlined by structural analysis for the specified design loads, consistent with the type of construction specified, or shall be a proportion of the required strength of the connected members when so specified herein. Where the gravity axes of intersecting axially loaded members do not intersect at one point, the effects of eccentricity shall be considered.
510.1.2 Simple Connections Simple conncctions of beams, girders, or trusses shall be designed as flexible and arc permitted to be proportioned for the reaction shears only, except as otherwise indicated in the design documents, Flexible beam connections shall accommodate end rotations of simple beams. Some inelastic, but self-limiting defOImation in the connection is permitted to accommodate the end rotation of a simple beam. National Structural Code of the Philippines 6'" Edition Volume 1
!:j.[)()
CHAPTEH 5 . Steel and Metals
510.1.3 Moment Connections
5IU.1.6 Beam Copes and \Veld Access Holes
End connections of restrained beams, girders, and trusses shall be designed for the combined effect of forces resulting from moment and shear induced by the. rigidity of the cOllnections. Response criteria for moment connections m'e provided in Section 502.3.61>.
All weld access ho!c.s required (0 facilitate welding operations shaH have a length from the toe o/" the weld preparation /l0{ less (han 11/2 times the thickness oj" the material in which the hole is made. The height of the access hole shall be
User Note: Sec Section 503 and Appendix A-7 for analysis requirements to establish the required strength and stiffness for desigll of connections.
510.1.4 Compression Members with Bearing Joints 1.
When columns bear on bearing plates or are finished to bear at splices, there shall be sufficient connectors to hold all parts securely in place.
2.
When compression members other than columns are finished to bear, the splice material and its connectors shall be arranged to hold all parts in line and shall be proportioned for either (i) or (ii) below. It is permissible to use the less seve-re of the two conditions:
a.
An axial tensile force of 50 percent of the required compressive strength of the member; or
b.
The moment and shear resulting from a transverse load equal to 2 percent of the required compressive strength of the member. The transverse load shall be applied at the location of the splice exclusive of other loads that act on the member. 'D1e member shall be taken as pinned for the determination of the shears and moments at the splice.
User Note: All compression joints should also be proportioned to resist any tension developed by the load combinations stipulated in Section 502.2.
510.1.5 Splices in Heavy Sections When tensile forces due to applied tension or flexure are to be transmilted through splices in heavy sections, as defined
in
Section 501.3.1e and 501.3.1d,by completc joint-
penetration groove (CJP) welds, material notch-toughness requirements as given in Section 501.3.lc and 501.3. ld, weld access hole details as given in Section 510.1.6 and thermal cut surface preparation and inspection requirements as given in 513.2.2 shaH apply. The foregoing provision is not applicable to splices of elements of built-up shapes that arc welded prior to assembling the shape.
User Note: ClP groove welded splices of heavy sections
df:~~~~~e~e:;f£[~ec~ts of weld shrinkage. Members
j
that are also
to tensile shrinka:~e if
j 1/2
times the thickness of the matelial with the access hole, t W'
but not !css tlHU1 25 !lllll nor docs it need (0 exceed 50 mll1. The access hole shall be detaikd to provide room for weld backing as needed. Fo!: sections that arc rolled or welded prior to cutting, the edge of the web shall be sloped or curved from the surface of the flange to the reentrant surface of the access hole. In hOI-rolled shapes, and built-up shapes with CJP groove welds that join the web~to-Oange, all beam copes lmd weld access holes shall be free of notches and sharp reentrant comers. No arc of the weld access hole shall have a radills less than 10 mill. In built-up shapes with fillet or partial-joint-penetration groove welds that join the web-to-flange, all beam copes and weld acccss holes shall be free of notches and sharp reentrant comers. The access hole shaH be permitted to terminate perpendicular 10 the Oange, providing the weld is terminated at least a distance equal to the weld size away from the access holc. For heavy sections as defined in 501.3.ic and 501.3.ld, the thermally cut surfaces of beam copes and weld access holes shall be ground to bright metal and inspected by either magnetic particle or dye penetrant methods prior to deposition of splice welds. If the curved transition pOJ1ion of weld access holes and beam copes arc formed by predrilled or sawed holes, that portion of the access hole or cope need not be ground. Weld access holes and beam copes in other shapes need not be ground nor inspected by dye penetrant or magnetic pal1ic1e methods.
510.1.7 I'hlcement of Welds and Bolts Groups of welds or bolts at the ends of any member which transmit axial force into that member shall be sized so that the center of gravity a/" the group coincides with the centcr o/" gravity of the member, unless provision is made for III eccentricity. The foregoing provision is not applicable to c; connections of statically loaded single angle, double ang); and similar members.
510.1.8 Bolts in Combination with Welds Bolts shall not be considered as sharing the load in combination with welds, except that shear connections v,< . any grade of bolts permitted by Section 501.3.3 installed i:.! standard holes or short slots transverse to the direction of the load are permitled to be considered to share the load with longitudinally loaded fillet welds. In such connections the available strength of the bolts shall not be taken as greater than
Association of Structural Engineers of tile Philippines
CHAPTER 5
50 PCft:1.!1l1 of the available strcngth of bcarin g-type bolts ll1 ("onnctlioll.
!h~~
In making welded aherillions to structures, ex.isting rivets and high strength bolt . . ligillcned to Ihe requi rcmcnts for slipcrili<..'aJ COlllh;!Ctions arc permittcd 10 beuliJized for ca rryin g JO;ld s pre-scllt
510.1.9 Iligh-Slrenglh with
Bolls
in
Rivets
Combinafion
III both new work and allenHiolls. in connec ti ons designed
Welded
Connections Pretensiollcd j oirHs, slip-crit ical joints or welds shall be. used for thc following connec tions:
J. 2.
3.
Column spli ces in all mult i-story structures over 38 m in height. Connection~
of all beams and girders to columns and
,IllY other beams and gi rders on which the bracing of columns is dependent in Slmc(ures over 38 In in height In all structures carrying cra nes of over 50 k.N capacity: roof truss splices and connecti ons of trusses to columns. column spli ces, col umn bracing, knee braces,
and crane supports 4.
Conn ecti ons for the suppon of machinery and other live loads that produce impact or reversal of load
Snug-li ghl ened joinlS or joinls wilh ASTM A307 bolls shall be permitted exccpt where otherwise specifi ed.
Slcol anci Mela l
!; 61
510.2 Welds
All provisions of AWS DI.I apply under thi s Specification, with the cxception that th e provisi ons of the listed NSCP Spccific'Hion Sections apply under th is SpecifiGation in lieu
of the ci led A WS provisions as follows:
NSCP Sleel and Melals Seelion 510. 1.6 in lieu of AWS DI.I SCClion5.I7.1 NSCP Sleel and Melal'; Seelina 510.2.2.. in li eu of AWS DI.I Seelion 2.3.2 NSCP Sleel and Melals Table 510.2.2 in lieu of A WS D I. I Table 2. 1 NSCP Sleel and Melal s Table 5 I 0.2.5 in li eu of A WS D 1.1 Table 2.3 NSCP Sleel and Melals Appendix A·3. Table A·3. 1 in lieu of AWS D I. I Table 2.4 NSCP Sleel and Mel als Seeli o n 502.3 .9 and Ap pendix A· 3 in lieu of A WS D 1.1 Seelion 2. Pan C NSCP Slccl and Melals Sccli on 513.2 ill lieu of AWS DI.I Secliolls5. 15.4.3 and 5.15.4.4 510.2.1 Grooye Welds 510.2.10 Effective Area The effec ti ve area of groove welds shall he considered as the length of the we ld times the effective throat thickness.
The effective throat thickness of a partial-joint-penclfation (P1P) groove weld shall be as s hown in Table 510.2.1. User Note: The effective throal size of a partial-join!: penetration groove weld is dependent on the process used and. the weld position. TIle contract documents should either
indicale the effective IlU'Oal required or Ille weld streoglh required. and 'the fabricalor should detail the joinl based 00 Ille weld process and position 10 be used 10 weld the joint. The effecti ve weld size for fl are groove welds, when filled flu sh to the surface of a round bar. a 900 bend in a fonned section, or rectangular HSS shall be as shown in Table 510.2.2. unless other effective throat s arc demonstrated by tests . The effective size of Oare groove welds filled less than flu sh shall be as shown in Table 510.2.2, lcss the greatest perpendicular dimcnsion measured from a line flush to the bnse metal su rfClce to the weld surface .
Na tional S lruc lural Code of Ihe Philippines 6 'h Edition Volume 1
5-,B2
CHAPTEr{ [) . Sled and Metals
-----------------------------Table 510:2.2
Effective Weld Sizes of Flare Groove
-,;;; -,; '-,_ •-", 'Welds Welding Process
Welding
"""""1'"n Process
Posi{:on F(llai), H (horiz.), V(vcrt.), I
Shielded Meta! Arc (SMAW)
All
Gas MClal Arc (GMAW) Flux Cored Arc
All
W) Submerged Arc (SAW) Gas Metal Arc (GMAW) Flux Cored Arc (FCAW) Shielded Metal Arc (SMAW)
Gas Metal Arc (GMAW) Flux Cored Arc (FCAW)
F
F,II
All
V.OH
Flare Bevel Groove!;01 Flare V Groove
1------ -------------------- -----------Groove
GMAWand
Type
Effective Throat
(AWS DI.I. Figure 3.3)
SAW
Groove 60' V
J or U Groove 60' Bevel or V
4S
·
Depth of Groove
'/2 R
ra)Por Flare Bevel Groove with R< 10 mm llse only reinforcing fillet weld on filled flush joint. General Note: R"", radius of join I surface
(can be assullled to be 21 for I-ISS), mm
I
·
Bevel
Minus 3 mill
Bevel
5/16R
I,
Depth of
·
5/8 Ii
-
Depth of Groove
4S
5/16 Ii
I
Bevel
4S
3/4 Ii
------------------1-----SMAWand FCAW-S
J or U
5/8 Ii
FCAW-()
Material Thickness of Thinner Part Joined, mOl
Minimum Effective Throat Thickness,!a) mIn.
Groove
Depth of Groove nus
3!
To 6 inclusive Over 6 to 13 Over 13 to 19 Over 19 to 38 Over 38 to 57 Over 57 to 150 Over ISO
3
5 6 8 10 13 16
1"ISee Table 510_2_ L
Material Thickness of
Thinner Part Joined, To 6 inclusive Over 6 to 13 Over 13 to 19 Over 19
I11Ill
Minimum size of Fillet weld,r'l) llun.
3 5 6
8
Dimension of fillet welds. Single pass welds be used. Note: See Section SIO.2.2b for maximum size of welds.
Association of Structural Engineers of tile Pl1i1ippines
C HAP TE F~
Larger dlcctivc throat thicklll!s~cs than those ill Table 510.2.2 arc permitted, pro vided the fabricator C<.Ill establish by qualdic
510.2.lb Limitations The minimum effective throat thickness of ;:1 partial ~joiJ1( penelnllion groove weld shall not be less Ihan the size required to transmit calculated forces nOT the size shown in Table 510.2.3 . Minimum weld size is determined by the thinn er of the two parts joined .
:)
5-13:3
The minimum effecti ve Icngl h of lilkt welds designcd 011 the basis of strength shall be no! less than fOllr tillles thl' nominal size. or else the size of the weld shall be considered not IU exceed 1/.1 of it s effecti ve Icngth. If longitudinal fillet welds arc lIsed al one in end conneclions of nat-Imr tension membcrs. Ihl'. length of each fillet weld shall be nOI less lhan the perpendicular distance between Ihem. For the effect of" longitudinal fillet weld length iJ~ end cOJlnections upon the effectivc arc;\ of the connectcd '.Jllember, sec Section 504.3.3. .. For end-loaded fillet welds with a length up to 100 limes the leg dimension, it is pemlitled to take the erfective length equal 10 the aeluallenglh. When the lenglh of the end-loaded fillet weld exceeds 100 times the' weld size. the effective length shall be delcnnined by multipl ying the nc(Ual lenglh by the reduction factor, p,
510.2.2 Fillet Welds
,6= 1.2 -O.OOJ:l/w)~ 1.0
510.2.2. Effective Arca The errective area of a fillet weld shall re the effcctive length multiplied by the erfectivc throat. The effective lhroat of a fillel weld shall be the shortest dislance from lhe root 10 the face of tile diagrallll1lmic weld. An increase ill effecti ve Ihroat is permilled if consistent penetralion beyond the root of the diagrammatic weld is demonstrated by tests using lhe producti on process and procedure variablcs.
S!ce! tl nc.! Met;)!
(510.2· 1)
where L
\\'
= actua llenglh of end·loaded weld, 111111 . = weld leg size. mm .
When the length of lhe weld exceeds 3(X) times the leg size. Ihe value of {J shall be laken as 0.60.
For fillct welds in holes and slots, the effective Jenglh shall be Ihe length of Ihe cenlerline of Ihe weld along Ihe center of the plane through the th roat. In tbe case of overlapping fillets. the effective area shall nOI exceed the nominal cross·sect ional area of the hole or slot, in the plane of lhe faying surface.
In tcnnittem fillet welds are pennitted to be used to transfer cakulated stress across a joint or faying surfaces when (he required strength is less than that developed by a continuous fillet weld of the smallest pemlilted size, and (0 join componenls of built-up members. The effective length of any segmel1l of intermittent fillet welding shall be not less lhan four times the weld size, with a minimum of 38mm.
510.2.2b Limitations The minimum size of fillet welds shall be not Jess than the size required to tra nsmit calculated forces, nor the size as shown in Table 510.2.4 . These provisions do not apply to fillet weld reinforcements of partial· or cOT11plel e~joilll· penetration groove welds.
In lap joints, lhe minimum amount of lap shall be five times the thickness of the thinner part joined, but not less than 25 nml _ Lap join ts joining plates or bars subjected to axial stress that utilize transverse fillet welds only shall be fillet welded along Ole end of both lapped parts. except where the deflection of the lapped parts is sufficientl y restrained to prevent opening of the joint under maximum loadi ng.
The maximum size of fillet welds of connected parts shall be :
Fillet weld temlinalions (I.fe pennilted to be slopped short or extend 10 the ends or sides of parts or be boxed except as limiled by the following:
).
Along edges of material less than 6 mm thick, nol grea ter than the thi ckness of the material.
2.
Along edges of material 6 111111 or Illore in th ickness, not greater th an th e thic kness of the mat eria l minus 2 mm, unless the weld is especially designated 011 the drawings 10 be buill oul. to obtain [uJl·!..Ilfoat thickness. In the as-welded condition, the distan ce between the edge of the base metal and the loe of the weld is pcnnined 10 be less than 2 mm provided the weld size is clearl)' verifiable.
1.
For lap joints jn which one connected part extends beyond an edge of another connccted part that is subjecl to calculated tensile strcss, filicI welds shall terminate not less them the size of the weld from Ihat edge.
2.
For cOllnections where nexibility of th e oll tslanding elements is required, when end returns are used, the length of rhe retum shall not exceed four times the nominal size of rhe weld nor half the width of the part
3.
Pillet welds joining transverse stiffeners to plate girder
th
National Structural Code of the Philippines 6 Edition Volume 1
5·84
CHAPTEr'1:
~j .
Steel and !v1ctals
webs J 9 mm thick or less shall end 110\ less than fou r times nor morc than six times the thickness of the web from the web toe of the web-lo-flange welds, except where lhe ends of" sliffeners are welded to lhe flange. 4.
Fillet welds that occur on opposite sides of a common plane, shall be interrupted at the com er common to both
welds.
The thickness of plug or slot we lds in lllmerial mm or Ic.<.;s in thickness shall be equal to the thickness of (he mat erial. In material over 16 mm thick, the thi ckness of the weld shall hi; at least one~ ha lf the thickness of the materia l but not less than 16 111m.
510.2.4 Strength The design
Usc!" Note: Fillet weld tCJlllinations should be localed
app,r\~xj~~latcly Qilt;,.,.wel'~,I .:sizeJ~om :'. o( ~le~:,.~ge ()f th~ sqJ~Jli!c:90·Ji" ,18 , : ~)~niiWA~. H9l~~~f)ij:~'~:, :,: ths~~~e. ' JP~~l,~l. -yillpl ~e\ds t"rminated at tll~ cnd ~fth e joint,' other 'ilion tllOse
cOlln~Jhlg .s tiffe))efs to -'girdei ,wcbs, ;aie ,noLa. ~!ltlse correCtioi~' . :" \'.
,, :'
" ' <, :'" .-,v""
< ,,.,,
"t?<
stre ngth, rjJ Rn and
the
allowable
strength.
n,
Rn/ of welds shall be the lower v:.ilue of the base material and rile weld metal strength determined according to the iilllil states of tens ile rupture, shear ruplllre or yielding as follows:
<, ,,'c',"I", ''-''''''.:., ,':'','
For the base metal Fillet welds in holes or slots are permitted to be used to transmit shear in lap joints or to prevent the buckling or separation of lapped palis and to join component s of built-up members. Such fillet welds may overlap , subject to the provisions of Section 5 10.2. Fillet welds in holes or slots are not to be considered plug or slot welds.
(510.2·2) For the weld metal (5 I 0.2-3) where
510.2.3 Plug and Slot Welds
= nominal stren gth of the base metal per unit area,
510.2.3a Effective Arca AIJM
= nominal strength of the weld mcta! per unit area, MPa = cross secl i on al area of the bas e metal,
AI\'
mm = effective area of th e we ld . 111m2
MPa
The effecti ve shearing Mca or plug and slot weld s shall be considered as the nominal cross-sectional area of' the hole or slot in the plane of the raying surface.
8
2
51O.2.3b Limitatious Plug or slot welds are permitted to be used to transmit shear in lap joints or to prevent buckling of lapped pans and to join component parts of built-up members. The diameter of the holes for a plu g weld shall not be less than the thickness of the part containi ng it plus 8 mm, rounded (0 {he next larger mill, nor greater than the minim um diameter plus 3 mm or il4 times the thi ckness of the weld. The minimum cen ter-to-center spacing of plug wclds shall be four times the diameter of the hol e. The lenglh of slot for a slol weld shall not exceed 10 times th e th ickness of the weld. The width of the slot slmll be not less than the thickness of the pan containing it plus 8 mm rounded to the next larger mill, nor shall it be larger than 21/4 times the thickness of the weld. The ends of the slot shall be semicircuhu' or shall have the comers rounded to a radius of not less than the th ickness of the part containing it, except those ends which extcnd to the edgc of the part. The minimum spaci ng of lines of slot welds in a direction tran sverse to their length shall be fo ur limes the width of the slot. The minimum cent cr- l() ~cen ter spacing in a longitudinal direction on allY line shall be two times [he length of the slot.
The values of ¢, Q,F/JM,f~l'and limitations thereon arc given in Table 510.2.5. Alternatively, for fillet welds loaded in-plane the design st ren gth, ¢ Rn and th e all owable stre ngth, 11II (0., of. we 11(S 'IS penniued to be determined as follows:
I/I=O.75(LIIF~ I.
0.=2.00(ASI~
For a linear weld grou p loaded in-plane tbrough the center of gravity
(5 I 0.2-4) where
Fw =O.60F"xx (J.()+O.50sinI. 5 e)
(510.2-5)
and
A...
= electrode classification number, MPa. = angle of loading measured from the weld longitudinal axis, degrees = effective area of the weld, mm2
Associatio n of Stru ctura l Engineers of tile Philippines
CHAPTER 5
User Note! . A jinear weld group is , one in _'which nil
clements ~re in a ii~l e or a;c paralieL
-'.
R""
,
For weld clements wi thin a weld group that
2.
ill·pJane and an alyzed using an instantaneous cen ter of rotati on method, the compollent's of the nomina l s trengt h, RIIX and R " .~.;"are 'permitted 10 be determ ined
as fo ll ows: (510.2-6) where
= effect ive area of weld throat of any i th weld
A"y
clement , 1ll1l1 2
= 0.60
F",j
""XX
(1.0 + 0.50 ' in
e)/ (I')
U
(510.2-7)
/ ( ,,) ~ [p (I .9 - 0.9 p )]0 ' (5 10.2-8) = nominal stress in any it h weld eicment. MPa. =
x co mponc lll of s tress ,
F Wi
= y compon ent of s tress, Fl1'i = LI;/ Ll"" rat io of clcmcill i deformati on to its deformati on at maximum stress = weld leg size, mIll. = disl
)I'
weld clement with minim uill b.u /'; ratio,
5JO.2.5 Combination of Weld s If two or more of the general types of welds (groove, fillct , pl ug. slot) arc co mbi ned in a s ingle joint, the st rength of each shnl! be sep.mllcly co mput ed with reference to the axi s of the group in order to determine {'he strength o f the combination.
5JO.2.6 Filler Melal Requirements The cho ice of eleclrodc ror use with comlcte·joim· pcnctrati on groove weld s subject lO tension normal to the effec tive are a shall comply with the requirements 1'01' matching filler meta ls given in AWS Dl .1
User Not~: TIle following User Note Table summari zes the A 'WS 0 I :_. I provisi ons for matching fiBer metal s, fest ric, ti6n,~, ~xist. , For 3. complet~ l.is.~or.base ll}ctals
c:hhcr
and prequali1ied h'1atching tiller metals',see AY'lS '". Dl.l , Table 3. 1. . ,
111111,
stress ievels, lincarly pr o po r tion e d 10 the critical de f ormation based 0 11 distance fr o m the instant aneous cent er o f rotati on, Ii, 111111. /j. III
0 . 209
(6 + 2to.:n
III,
dcf'o rmationof
weld clemenl at maximum stress, in. (mm)
= 1.087(0 + 6ro.c, :'i1l' ~ O. J 7\\', deformalion of
All
weld clement at ulliJ113le stress (fracture), usually in elemen t furthe st frorn instantaneous cen le r of rotati on, mill .
l.
Fo r fille t weld groups concentrically loaded and consistin g of e lement s that arc oriented bot h longitudinally nnd transversely to the directio n of applied load, the combined strength , RII, of the fillet weld group shall be determined as the gretHer of (510 .2-911) or
(5 10.2-9b) where
R1,.,
5·85
= the Lolal nomin al strength of transversely loaded fillet welds, as determined in accordance with Table 510.2,5 without the alternate in Section 5 10.2.4(a), N.
= defonn nti oll of we ld elements at int ermediate
LI;
Sieel and Metal
= the total nom in al strength of longitudinall y louded fillet weld s, as dctermjn ed in accord ance with Table 5 10.2.5. N.
Nati on(~ l Structu ral Code of Iht7 Pililippin es 6 Edition Volume 1 th
:5·86
CHAPTIOR 5 - Slc QI and Metals
Load Type and Direction
Relative \0
Nominal Pertinent Metal
Arca
Strengt h
(FilM
Weld Axis
(1/'
FlY )
lAHM or A w ) mm1
N
Mmching filler metal shall be used. forT and comCf joints wilh backing left in place, notch lough
Strength of lhe:joint is controlled by the base metal
Tension Nannal to weld ax is
Required Fi ller
Effective
metal is requirecl . See Section 510.2 A ! Fill er meta l wilh a .
Compression Normal to weld axis
Strcnglh of the. joint is controlled by Ihe base metal
level equal 10 or olle strength level less than matching filler metal is
Tension or
Tension o r cOlnprcssi'01l in pans joined parall el
Compression
to a weld need not be considered in des ign of
Parallel to weld ax is
welds joining the parts.
level equal to or less Ihan matching filler metal is r Matching filler metal shall
be used. Ie}
~=±=-'~::-:-
Base
Tension Normal to weld axis
$ ~ O.80
Weld
Column to base
than columns as described in 510. 1.4{b)
Co mpression Connections not fin ished-la-bear
Fy
O.6OFlixx
Q ~ 1.88
Sec 5 10.4
Sec SIO.2.1a
Compressive stress need 110 1 be considered in
Plate and column splices design ed Compression Conncctions or mcmbers designcd to bear other
$ ~ O.90
design of welds joining the part s. ¢
Base Weld
=:
0.90
Q= I.67 ¢ = 0.80 n ~ 1.88
Scc
Fy
5 10.4
O.60f;,:xx
Sec SIO.2. Ja
F.\,
Sec
Filler metal with II strength level equal 10 or less than matching filler metal is penniltoo.
Base Weld
Tension or Compression P.arallello weld axis
9=
n '" 9 n=
510.4
Lli7
O.90FEXX
Sec 510.2. 1'
Tension or compression in parIS joined parallel
to a weld need not be con sidered in design of welds the
O.60FEXX Weld
Sec
510.2.1a
Association of Structural Engineers of tile Philippine s
CHAPTEH 5
,
Lo;;ld Type and Di recli on Relati ve 10
-
Weld Axis
S hear
= 0,75 n = 2.00
Efrcctivc Area
Requircd Filler
(A1JMol'A,.,)
Strcngth Lcvc!lallbl
Sec
Filler me tal wilh ;t strength level equal to o r less than matc hing filler metal is permitted.
510.2,2:1
Te nsion or comprcssiolll in pans joined parallel 1011 weld need no t be considered in design of welds ' the
weld axis
Base
Shear Pa mllel to f;'lyi ng surface on the
Filler metal wilh II st rength level equlIlto or less than
Governed by 5 J 0.4
$ = 0,75
Weld
cffccti vc area
5-87
Mewl
mill:!
~
Weld
Tension o r Compression J>ar~tI!ellO
NOlllimll Sirength (11J11f or '~vl
I'eltinent Melal
Steei a nd Metai
matching filler metal is pcnnittcd .
510.2.3<1
Fur nmtch ing, weld IIlclal sce I\WS 1)1 . 1, Secliun JJ.. Fillc r mel;11 with;o ~!rcnglh kl'd nile .~ I ren<,t h grc;l1er 11i:1Il m;IlChi11~ is Filler metals wilh ;1 ~u<: nglh !cl'\!! h:.~s lhan tll;uclti ng may be u~cd fo r groo",.. w,-Ids bc!wecn the webs and fI;!lIgc s ur buill-Up sections tt,II1SICITilig shcar loads. ~\r j' . . \\'h('n~ high r<:s!raim is a concern. In thc~c applieatitln~. the weld joinl sh;tli IX' det,\iletl and till', weld shall be designed lIsing lhe lhickn~ ss of lh~ malerial as
kwl
i
lhroat.
¢:=o.SQ n", I.SS
~~; ~:':;:,~:;::~;:,,:":~',;I';i·:O::" :i:sii,~o;n.~ of ~.
Iii
p-ermined.
:Llld O.60FE:XX liS the nO!ninal strcng,lh.
510.2.4(,1) are pennillcd ]llOvided the Ilcforma\ion c(llllr~\ihi ]i l yoI' the I':lr;j)us weld clclllenls is ennsidCf("1. ,\llcmalivc1y. Scctions 510.2A(b)
510.2.4(:1) tha i prO\'idc fur deformation
compat ibil ity.
510.2,7 Mixed Weld Metal Filler metal with a speeified Charpy V-Notc h (CVN) tou gh ness o f 27 J at 4'Cshall be uscd in the !'o llowin g joints:
When Charpy V-Notch toughness is specified, the process consumables for all weld metal , tack weld s, root pass and subsequent passes deposited in a joint shall be compati ble to ensure notch-tough composite we ld mctal.
1_ Complete-joint-penetrati on groove welded T ,md
510,3 Bolts and Threaded Parts
comer joillls with sleel backing left in placc. s ubject to tension normal to (he effective area, unless the joints are designed using the nominal strength and resistance factor or safety factor as applicable for a PJP weld. 2.
Complete-joint-penetration groove welded splices subject to tension normal to the effective area ill heavy secli ons as defined in 50 1.3. Ie and A3_ Id.
510.3,1 High-Strength Bolts Use of high-strength bolts shall conform to the provisions of the Specification for Structural Joints Using ASTM A325 or A490 Bolts. hereafter referred to as the RCSC Specification, as approved by the Research Council on Structural Connections, except as otherwise provided in thi s Specification,
The manufacturer's Certificate of Con formance shall be sufficient evidence of compliance.
National Structural Cod e of the Philippines 6'" Edition Volu me 1
'-
.
5·88
CH APTER 5 • Steel and
r -'"
~I/leta!s
< Table 51 O.3~1
-',-
I::,,:::;: F1~~~ ."r:·~~.:·:' I' ,":\~,
I
, . " ... , .~"
'"
,.
-,.,
'\.",.')5"
;;;"
;"" .. -"
,'i. ," .(MiiiimulJj!Jlolt\l'i'ete~~io#;i~'~ " .W'gi
:~~
I
:~!
M24
205
M27
267
I
~~~ 257
01
I
Nominal Shear
Description of Fasteners
Nominal Ten sile
Stress, l4~1I' Con nections. l~:,v' MPa MPa A107
boll~
310 [allt>1
165 tbl!cll fl
620 lei
330 If!
A125 or A325M tXlII!>, when threads ~ 1:.qlli\1
1(1 0 70 Ulnc,~ lhe tlLmullum 1t'11!.1It' J'lrt'/Iglh uf bolts. ountk d orr LO 11l'.U~St kN. S st>CClficd III AsrM sp<.'Clflcallo ns for A125M and A490M loll, \\Ilh UNC lllle,ub;
Stress in Bearin g-Type
ilre
nol
I!xc!uded
from shclIr planc);
4 !4t11
A325 or A~25M bolts, when threads arc excluded from
When assembled, all joint surfaces, including those alij,acent to the washers, shall be free of scale, except tight mill scale. All ASTM A325 or A325M and A490 or A490M bolts shall be tighrened to a boll tension 1101 less than th ilt given ill Table 510.3.1. except as noted below. Except as permitted below. install ation shall he assured by allY of th e following methods: tlirn-of~l1ut method, a direct tension indicator, calibrated wrench or alternative d(~sign bolt.
shear planes
~-~------~----~-I-~- -----~ 7801<'1
A400 or A490M bollS, wilen threads: arc not excluded
414 [0
from shear pl,l1les
._- - - - - - - - - - - - - - - - _ . _ - - 780!d
A490 or A490M bolls. when Ihreads arc excluded from
520 In
shear planes
Bolts are permitted to be installed to only the snug .. tight condition when used in paris meeting the requirements of Section 510.3.4, when threads arc nOI excluded frorn shear planes
!
Thrc..ldcd
I.
bearing-t ype connec ti ons.
2.
tension or combined shear and tension applications, for ASTM A325 or A325M bolts only, where loosening or fati gue due to vibration or load flucllHuio ns arc not design considerations.
The sil ug-tight condition is defined as the tigbtness attained by either a few impacrs of an impacl wrench or th e full dfolt of a worker with an ordinary spud wrench thaI brings the cOllnected plies into firm contact. Bolts to be tightened only to the snug-tight condition shall be clearly iden!ified on the design and erection d rawings. When ASTM A490 or A490M boils over 25 mm in diamcter are lIsed in slotted or oversized holes in ex tern al plies. a single hardened washer conforming to ASTM F436. except with 8 111m minimum thickn ess, shall be used ill lieu of (he standard washer. User J'lote: Washer re.quirements are proyided in the R.CSC Specification, Section 6. -
O.75F., [(1ld)
I
..
Thrcadetl parts mecting Ihe
requiremcnts
of Scc li o n
510.3.4. when threads arc excluded from shell!' planes
050FII
!.oISubjl.'CIIO Ihe rc! luiremc ll b or l\ppt!lIo.iix 3.
[~I r'"(l" 1\107 holls the I:lhlllatcd ",IIIlCS sh:11! hI.' rcdu('('d by 1 rlCrcc nl over 5 diame[crs of ICII!![ h ill the grip. J'1"nUo.!ilds permitted in ~ tlCilr planes.
fIJI'
\'ach 2 111111
[d""he nominal tensile slreng!h of !hc threaded ponioll o f an upset rot!. bilscd UpUIl the cro.~ ·scct ion:l l area :ll il.!; major thrcad diamclcr. AD. which sh~n be larg<.'r Ihall
tm; nominal bod)' ;UC;I of the rod hefore upseuil1~ times I /~)' «) For A32 5 0)' A32 5M il11d A490 or 1\490M bolls su hject 10 tell~il c fali gllc loading,
sec /\ppc nd ix 3. 1'1Whcn hcari ng.typc COIlIlcctiulIS u~l'd 10 splice tcOSill1l mcmhcrs h:I\'~' :i (listener jl,mcnl who!ic:: kngtll, I1Ic.'Rl>u rcd parallcl 10 the hne or force. c.u·c('(L~ 1270 mill. lahuhucd valucs sh;lll be reduced by 201lCrccIIL
Asso ciBtion of Stru ctu ral Enginee(s of the Philippines
fiN 'i" :;0
CH APTER !)
In sl ip-critical con nections in w hich the d irec ti on of k}(lding is toward a n edge of a connected parI, adequate ava il able bearing strength shall be provided based upon the applicable
req uirements of Secl ion 5 10.3. 10. V\' hcn bolt requirem ents cannot be provided by ASTM A325 lIn ei A325M, FI 852, or A4 90 anel A490M bolts because o j' J'l 'quiremcn ts for lengths exceeding 12 diameters or diameters
exceeding 38 1m}). bolts or threaded rods conforming to AST M A354 Gr. BC, A354 Gr. BD, or A449 arc perllli lled to be used in acco rdance with the provisions for lhrci.ldcd roels in Table 510.3.2. W he n AS TM A3 54 G r. BC, A3 54 Gr. BD. or A449 bo its a nd th readed rods arc ll sed in slip-cri tical co nnections, the bolt geometry including the head and llut(S) shall be equal La or (if large r in diameter) proportional to that prov ided by AST M A325 and A325M, or ASTM A490 a nd A490M bolts. Installati on shaH comply with all appli cab le requirement s of' the RCSC Specification with modilicatioll s as requ ired for the increased d ia me ter andl OJ' length to provide the design pretension.
510.3.2. Size 'Illd Use ofl-loles T he ma ximum sizes o f ho les for bo il s are given ill T a bl e 5! 0.3.3 , except that larger holes , required for tolerance on location of anchor rods in concrete foullu at ioIlS, ~l l'e penniucd in columll b;'ls e details.
Steei and Meta!
5-89
Ove rs ized holes arc perm itt ed in any o r all pl ies of slipcri ti cal con ncct ions, but they sh,,11 Ilot be used in bearingtype connections . Hardened washers shall be installed over overs ized holes in an Oll ter ply. S hort-sl otted hole." are pcnni tted in any or all p lies of slipcritical or bearing-type conn ections . The slots arc permitted witho ut rega rd to d irect ion o f loading in s lip-criti ca l connectio ns, but the length shall be norm;ll to the direct ion of the load in bearing-lype connectiOns. Vvashers shall be insta ll ed over Sh0l1-slo tled holes in an ouler ply; when highstrength bolts are used, such washers shull be luU'
510.3.3 Minimum Spacing The di sta nce be Lween centers of stand ard , oversized , o r slotted ho les , shall no t be less than 2 2f:, times the nomi nal diameter, d, of the fastener; a distance of 3d is preferred . Hole Dimens ions 13,111 O;alU~l.:'r
M1 6
M20 M22 M24 M27 M30
?:M36 _ .
S!;lIldanl (DI;t )
IS 22 24 27
Owrsi~.o.:
(Dia)
20 24 28
30
30 35
33 d+3
38 d+8
Sho n -Slot (Width x l..englll)
8).; 22 22x 26 24 x 30 27 x32
30 xl? 33 x 40 (i/+3)x(d+ 10)
L(llI~ ·S !"t
( Width xLcngth)
18 x 40 22 x 50 24 ;( 55 27 x 60 30 x 67
33 x 75 (,/ + 3}.\' 2.5 (/
--
Standard holes or short-slott ed holes transverse to the direct ion of the load shall be provided in accordance wilh the provisions of this specification, unless oversized holes, ShOIl-sloned holes parallel to the load or 10ng-sloHed holes are appro ved by th e e ngin eer-of-record. Fin ger shims up to 6 mIn are permitted in slip-c ritical connection s designed on the bas is o f standard holes w ith out redu cin g the nomin al shear strength of the faste ner to that specifi ed for slo Lted
510.3.4 Minimum Edge Distance The distance from the center of
i.\ s ta nda rd ho le to an edge o f a co nn ected part in a ny d irection sh all not be less th an eit her the
User~~~~: '['h~ edg~. 9istaIl~es< in T,~l>les . ~ JO.~.4 me
minil!ju,rn ""e,dg~ " ".djstal~~es : ,:,' bas~ .·on stal1~ard fa~ric~,tion Pf"J.cticcs and . workmanship tolerances. The appropdate provi sions of S eclions 510.3.1 0 and 5 J0.4 muSI be sa ti sfi ed .
holes.
l\lationa l Structu ral Cod e of tile P hili ppines
(-3(11 Editio n
Vo lume 1
[;.·gO
GHAPTEFl S . Steel and Metals
;\;:",;,.; :::,';' '.. ':Tjbjt51013~5,' ','
510.3 .5 Maximulll Spacing a nd Edge Distauce
", '.
':'vid~isilf;EdglDJ~lliri'~~Iiicr~riieilt Ci,:itiJh:~'"
The IIl
Slo((ed Holes -.-----~---
Nominal l)iamctcr of Fastener (mm)
I Al ug Axis Pcq ){'lUlkulilr
wEdl:1!
Oye rslzed
I AlII~ Axis
I'andle! (0 Edge
Holes
<22
2'
LOllf,
ShUr1 Slots
Sims . 1
3 3
O.75d
0
>27
Boll Dj.ullcle!" (mill)
AI
Sheared Edges
1
1. IWhcn !cnVlh of ~ t lJl is bs tliall n~.timutll aHI)W"~bt~ (see Tallie ~IO. 3.JMJ. C2 hi pcnniucd to be rcduC'c-U by olle·h:oIr the tl iffercnc\! txll"."Cen til ... maximulll :mtl :K'lu.l1 ~IOI !C'flg!hs.
A. Rolled Edges of Platc,o;.
Shapes or Bars. or Thermally Cut Edges I~I
I !
fal
28 3'
22 26 28 30 3'
'6 20 22 2' 27 30 36
42141
6<
38 '6
Over 36
1.75d
I.2sd
38 hll
'8
52
1,c~~1 ... d~ discttlCti JR permitted 1(1
Ix used pn1\'ided pro\·isiolls
I.
For painted membe rs or unpainted mc mbers not subject In corrosion, Ihe spacing shnl! nOl exceed 24 limes 111<:. thickncss of thc thinncr plate 01' 305 III Ill.
2.
For unpainted members of weathering steet subject III atmospheric corrosion. the spacing shall lIot exceed l--i limes the th ickness of thc Ihilmer platc or 180 mm .
5JO.3.6 Tension and Shear Strength of Bolts and Threaded Parts 0(
Scchuu :'i IO.1JO. II~ appropri:uc .•1I1! S3li ~l'i ... d. !bl FOI ovcfsilCd or ~ t(111cd hok:~. sec Tab le 51003.5 fel All edge distances in 1 111~ co\umn ;"c permitted 10 be ,cducl,:d 3 I1In\ Ihe hok U ;I! a [)Oin! where required s lreuglh docs not exceed 2:'i perccill of the m:u.:illlulO Slten&th IheciemCn! . Idlll,e~c .\IC pcmliltcd 10 be 32 nun ~t the em.1I of bealll eonOC(1ton ~n&lc$ . sh... ar end plates.
The des ign tell sion or shear sirength. f/J RII • and the 3110wablc tension or shear strength , R,JQof a silug-lightened or pretcnsioned high-strength bolt or threaded p:u·t shaH he dctermined according to the limit states of tensile lupturc Hnd shear mpturc as follows: (510.3- 1)
¢=O.7':{LRFQ
Q =20CX:ASD)
wl)ere
F,,,.
J:;,
= nominal .cnsile SIre"
A/,
Slress, F,,,.from Tab le 51 0.32,M p" :::: nominal unthrca(/cd body area of bolt or threaded pan (for upset rods, sec footnot e d, Table 5 10.3.2). m",'
or shear
The required tensile strength shall include any I!'l ';;' } resulting from prying action produced by dcfoflnali ul;"': : , .~ connected pm1s.
Association of Structural Engilleers of Ihe Philippines
CHI\PTEH 5
510.3.7 Combint'd T ensioll and Shl'ar in Ilc.ilringType C onn ec ti uns The ilvailablc tensil e strength or
¢ = 0.7 _~LliFlJ
resistance. R"jQ,shall be detcrm ined for the li mit slip as follows:
For co nn ections .in
whi ch prevention
or sli p is a
se rv iceability limit state
f~, ::::: nomi na l (ensil e Slress modified effec ts of sheari ng stress, M pft
(0
ind udc the
For connec tio ns designed strength leve l
I~"f\. S F", (LRFD ) F,l,. ::::: 1.3F,,, - $F,w
1'1= LSO (ASD)
:$;
(0
JI
;; mea n slip coeffi cient for Class A or B surfaces, as appli cable . or as es tablished by tests ;; 0.35 fo r Class A su rfaces (unpai nted clean mil l scale sleel surfaces or sUlfaccs wit h Class A coalings on bl a<;I-eJeaned steel and hot-dipped
Fm· = no mi n
galvanized and ro ughened surfaces)
= 0.50 for Class B surfaces (unpainted bl as t-
Thc available sh ear stress of the fastener shall equal or cxceed the req uired shear s trength pe r unit Jrea,F, User Note: Note that when the req uired stress,f. in either shear o r tcnsion. is less than or equal to 20 percent of the corresponding availab le stress, the effects of combined stress need not be invest iga ted. Al so note th al Equations 5 10.3-3a and 51 0.3, 3b can be rewritten so as to find a
Du
cleaned steel surfaces or surfaces with Class B coatings on blast-cleaned steel) ;:: J .13; a multiplier that reflects the ratio of the mean installed bolt pretension to lhe specified minimum boh pretension. The use o r other va lues may be approved by the engineer-of- record.
11.\( = hole fac tor determined as follows:
nomina l shear stress, F~\" as a fu nction of the required [ensile stress.[,..
For standard size holes
(II)
Slip- C riti cal
Connections
High-s trength bolts in sli p-c riti cal connections arc permitted to be designed to prevent slip either as a serviceability limit slat e or at the required stre ngth limit slate, connection mu st also oc checked for shear strength in Hccordancc with Sectio ns 510. 3.6 and 5 ! 0.3.7 and bea ring stre ngth in accordance with Sec tions 510.3. 1 and 5 10.3.10.
nlC
Slip-cri tical connecti ons shall be designed as follows. unless otherwise des ignated hy the cnginecr- of- record. Connections with stJndard hol es or slots transverse to the direction o r rile load shall be de sign ed ror slil) as a scrvicc:lbility limit state, Connections with oversized holes or slots p"rallel 10 Ihe directio n of the load shall be designed to prcvclll slip;,1t the rcquired strength level.
h,,_= I .00
(b) For ovcrsizcd and
short-slollcd holes in
.Q= L76(ASD)
where
Fm. (ASl) . 'J
510.3.8 High-Strength !lolls
prevent slip at (he req ui red
¢ = 08S(LRFLi
~II =nominal (cnsile stress fro m Ta hlc 5 10.3.2 , M Pa
I ..
sl(II C o r
(5 10.3-4)
1'",.
5,91
The design slip resistHl1ce, ¢ R,p and the allowable slip
whe re
~ -n./~1I l "m::::: 1.31-,,( -'- . /'..
S!eei and Metal
Nl Til
h,,, =0.85
(e) For long-sloHed ho lcs h". =0.70 ::;: number o f slip planes ::;: minimum fastener tension given in Table 510.3.1, kN
User Note: TIlere are special cases where, with oversize . holes and slots parallel to the load, the movement possible due to connection slip cou ld cause a structural fai lure. Resistance and safcty faclors arc provided for connccti ons where slip is prevented unt il the req uired strength load is reached. Design loads are used for either design method . and all
connections must be checked for stre ngth as beanng·rype connections.
U1
Nation al Structural Code of the Philippines G Edi tion Vol ume 1
CHAPTEH:>· Steel and MClals
5·92
510.3.9 Co mbined Tension and ShcH!' in Slip .. C riti cal
Fu
= specified mini m um ten sil e strength of the
Le
= clem' di stance. in Ihc direction of the force,
ConnecOo ll s
connec ted materia l, MP"
When a slip·critica! connection is subjected to ;;111 applied ten sio n that reduces Ihe nct d
between the edge of the hule and th e edge of th e .uljacelll hole or edge o f the mat erial. mill
ll1ulliplied by the factor, k.r , as foll ows:
= thi ckness of cOllllec ted material. mill (510.3·5a)
k,
=I
(5 10.3·51»
where
= number of bolts carrying the applied te:nsion = tensi o n force due to ASD load combin a ti ons,
7~,
=:
510.3.1, kN. tcnsion force due kN.
to LRI~D
The nominal strength of spec ial fasteners o ther than the bolts presented in Table 5! 0.3.2 shal! be verified by tests.
load combi nati ons.
510.3.12 Tension Fasteners When bolts or other fasteners in (e'nsion arc attached to an unstiffened box or HSS wall, the strength of the wall shall be determined by rational analysis.
510,3.10 Hearing Strength at Holt Holes The available bearing strength,
q,Rn and R,Jn, flt
bolt
holes shall be detemlined for the limit sta te of bearing as
follows:
¢=O.75(LRFf~ I.
a.
510.4 Affected Elcmcnts of Members and Connecting Elements This section applies to elements of membe rs at connections
Q=200(ASq
and connecti ng elements. such as plates. gussets , angles,
For a bolt in a connection with standard. oversized, and Sho ll- sJolted hol es, independent of lhe direc tion of loading, or a lon g-s lolled hole with the s lo t parallel to the direction ort he bearing force: when deformation at the bolt hole al service load is a de sign co nsideration
R" = 1.2LJF"
Bcaring strcngt h shall be chec ked for hoth bearing-type and s ljp ~c ri(i caJ co nn ection s . Th e usc of overs ized holes and short· and lo ng -s loH ed holes para ll e l ( 0 th e line of force is restri cted to s lip -critical co nnecti ons per Section 510.3.2.
510,3,11 Special rasteners
kN.
= minimum fastener tension given ill Table
1i,
For co nnections, the beating resistance shall be taken as the sum of the bearing rc~i s lan c cs of the i ndi vidual bolts.
5, 2.4d1F"
(510.3·6a)
find
5 10.4.1 Strength of Elements in Tension The design s tre n gth ,
Rn /n ,
and the a llo wab le s tren ti h,
of affected a nd connecting clements loaded in
I
For tensile yielding of connecting elements:
when defoml
11" = 1.5J.,1F" o,3.OdIF,. C.
¢R".
tension shall be the lower value obtained according lo the limil slates of tensile yielding and tensile n1pture .
1. b.
brackets.
(510.4- 1)
¢=090(LRFq
(5 10.3·6b)
For a bolt in a connection with long-s loHed holes with
2.
Q
= 1.67 (ASD)
For tensile nlplurc of connecting e le me nts:
the SIOI [>Clpcndicular to the direclio n of force: (510.3·60) d.
For connections made using bolts that pass compll~ lcly through an unstiffencd box member or HSS, see Section 510.7 and Equation 510.7·l,
where
d
= 1l01!linal holt diameter, mm
¢=O.7S(LRFD,
Q=200(ASq
where At'
= effective net area as defined in Section 50~. :; 3, 111m 2; for bolted splice plat es , A, = A" 5, 0.85A,
Association of S tructura l Engineers of the Philippine s
CHAPT [11 :;
Steel r.wc! Met;li
510.4.2 Strength of Elements in Shear
for KUr > 25 the provisions of Sectio n 505 apply,
The ilvaililhlc ~hc
510.5 Fillers
III the limi! stales uf sl1ear yielding and shear IlJplurc :
For sheilI' yielding of the clement:
J.
(5104·3)
Q = 1 .5()(AS~
¢= Loo(umJ 2,
For shear rupture of the clement: (5104-4)
¢=O.7S(LRFq
In welded consllllction. any filler 6 mill or more in thickness shall extend beyond the edges of the splice plate and shall be welded to the part 011 which il is Ijtt ~d with sufficient weld 10 l rall~mit th e splice plate load, applied at the su rfac.:c of the filler. The welds joining the splice plate to the filler shall be sunicicllI 10 transmit the splice plate load and shall be long enough [0 avoid ovcrJotlding the filler along the toe of th e weld . Any filler less than 6 111m thick shall have its edges made nush with the edges of the splice plate and the weld size shall be the sum of the size necessary 10 caJTY the sp lice plu s the thickne ss of the filler plate. When a bolt th at carries load passes through fillers thai arc equal [0 or less than 6 mm thick, the shear strength shall be used without reduction. When a bolt that carries load passes through fillers Ihat arc gretltcr Ihan 6 !Hm thick, one of lhe following requirements shall apply:
where A,iI'
~)-93
== net area subject to shear, mnl.
510.4.3 Block Shear Strength Th e available st rength for the limit sta te of block shear rupture alollg a shea r failure path or path(s} and a perpendi cul ar tension failure path shall be taken as
I.
For fillers that are equal to or less than 19 mm thick, the shear slrcnglh of the boilS shall be mul1iplied by the factor II - 0.4(1 - 0.2 5)J [S .I.: II - 0.01 54 (1 - 6)JJ.
where I is the total thickness of the fill ers up to ! 9 mm 2.
The f,lIcrs shall be extended beyond the joint and the filler extension shall be secured with enough bolts to unifomll y distribute the total force in the connected element over the combined cross section of the connected clement and the fill ers;
3.
The size of the joint shall be increased to accomlllodate a number of bolts thai is eq ui valent to lhe lOla I number required in (2) above; or
4,
The joint shall be designed to prevent sli p at required strength Icvels in accordance with Section 5 10,3,8.
(5IOA·5 )
Q=2.00(ASq where A g ., = gross area subject
(Q
shear, 111m2
Am ::::- nci aren subject to tension. mm2 Am' :;:nct area subject
to shear, mm ]
Wh ere thc tension stress is uniform, Ub.t == J: where the tension stress is non uniform, V')s :;:0,5. User Note: The cases where Ubs must be taken equal to 0.5. 510.4.4 Strength of Elements in Compression
For KUr $25 (510.4-6)
Q
Groove~welded s plices in plate girders and beams shall develop the nomi nal strength of the smaller spliced section. Other lypes of splices in eros-ii sections of plate girders and beams shall develop the strength required by the forces at the point of the splice.
510.7 Bearing Strength
The ava il able strength of connectin g clements in compression for the limit stale., of yie ldillg and buckling sll
P" = FyAg
510.6 Splices
The design bearing st rength, ¢ R11 • ilnd the allowable
In,
bearing strength, R/I of surfaces in contac t shall be determined for the limit stale of bearing (local compressive yielding) as foll o ws:
¢=O.7S (LRFq
= 1.67 (ASD) The nominal bearing strcngth,Rl/,is defined as follows for
the various types of bearing: Nalional Struclural Code of the Philippines 6 'h Edition Volume 1
.'-'"1)
!; ·9t1
I.
CHAPTER 5 . Steel and Meta ls
For mi lled SUrf'ICCS, pins in reamed, drilled. or hored h()les.lmd ends offiued bearing stiffeners:
(510.7·1) where
= specified minimum yield stress, MP,I :; projected bearing area, Illln 2
2.
For expansion rollers and rockers
n.
fd S635mm
5 10.9 AndlOr Rods Hnd Embedments Anchor rod s shall be designed 10 provide Ihe rClJui l'cd resi stance to loads on the. completed strucHlrc al the base Dr columns including the !let tensile components of illly bendin g momenl Ilwl Illay rcsu l1 from load combinations s lipuJ;llcd in Section 502 .2. The anchor rods shall be de.... ignc-d in accordance wI,h the requirements for thread ed parts in TaI1I 0 510.3.2. Larger oversized ;\nd slotled holes arc permitted in base plates when adequ
(5 10.7·2) r~e rl11 i tted ho le s izes and corresponding washe r dime nsions are given in the AlSC Manual of Steel Construction
User Note: The
b. If d > 25 635 min
(SI ; Rn = 302(F) -90Y,1/20)
(51O.7·}M) (S IO.7.})
where ;: d iameter, 111m = length of bearing, n11ll
d J
W hen horizon tnl forces nrc prcsclH at column bases, th ese rorces should, where possible, be resis ted by bearing agai nst concrete eleme nts or by shear frict ion between the column base plate and the foundation. Whcn anchor rods <-I re (~ s igncd to res ist horizontal force th e base plate hole size, the anchor rod setting toleran ce, a nd th e horizo lll al movement of the column shall be conside red in th e des ign.
510.8 Column Bases and Bearing on Concrete Proper provision shall be made to transfer th e co lumn loa ds and mome nt s to the fOOlings and fou ndati ons.
User Note: See Chapter 4 for embedme nt design and for shear friction design. See OS HA for special erection requirements for anchor rods.
In Ih e absence of code regulations. the design bearin g strength , fA PI" and the allowa bl e bearing strengt h,
510.10 Flanges and Weos with Co ncentrated Forces
P" l ilc ,for the limit state of concrele cru shing arc penni tl ed
10
be taken
ilS
fo llows:
<1>, = 0.60 (u mi
.Q, = 2S(ASD)
The nomi nal bearing strength, PI" is de termined as follows:
I.
On the full area of a concrete support : Pp =O.85f~A,
2.
(510.8· 1)
On less than th e full area of a conc rete SUPPOI':
(510.8·2) where
A,
A2
;: area of sleel concentrica ll y bearing 0 11 a 2 concrete su pport, rnm ;;; maximum area of the portion of the suppol1ing surface that is geometrically similar 10 and co nce ntric wi th the loaded area, mm 2
This sec ti on applies to sing le·a nd doublec oncentrated force app lied norma l to the fl ange(s) of wide flange sect ions a nd simi lar built -up shapes. A singleconcentrated force can he ei the r tensi le or compressive . Double-concentrated forccs are o nc tensi le and one compressive and form a couple on the same side of the loaded member. When the required strength exceeds the available strength as dctennined for the limit states listed in this section, stiffener.-; andlor doublers shall be provided and sh~ll be sized for Iht difference between the required strength and the avai lahlc strength for the appl icable limit state. Stiffeners shall also lll(;t1. the design requirements ill Section 5 10. 10.8. Doublers ~; h: .i i also mce{ the des ign requ irement in Scc li o n 510. 10 .9. User Note: See Appendix A-6.3 for requirements fo r the ends o f cantilever members.
or
Stiffeners arc required at unframed e nds beams ill accordance will I the requirclnents of Seelioll 510.10.7.
510.10.1 Flange Local Bendin g Thi s section appli es to ten sit e sin gle-co ncentrated forces
and the tensile compone nt of doub le-conce nt rated forces.
Associa tion of Structu ra l Enginee rs of the Phi lippines
CHAPTER 5
The design strength, ¢ Nn , and the allowable strength,
R,)r.2.f'or the limit state of flange local bending shall be determined as follows: Ii" = 6.251 j 1",1
(510.10-1)
Q= 167(AS~
¢=O.90(LliFll where
= specified minimum yield stress of the flange,
MPa
I".
web thickness, 111m
510.10.3 Web Crippling This section applies to compressive single-concentrated forces or the compressive component of doubleconcentrated forces. The available strength for the limit state of web local crippling shall be determined as follows:
¢=O.75(LliF~
If the length of loading across the member flange is less than O. ISlh, where h, is the member flange width, Equation 510.10-1 need not be checked.
I.
When the concentrated compressive force to be resisted is applied at a distance from the member end that is greater than or ~ual to &2: R"
When required, a pair of transverse stiffeners shall be provided.
=08CX~.[I+-l NY ~)J.5l "\d AI!
2.
a.
When the concentrated compressive force to be resisted is applied at a distance from the member end that is less than d12: For Nld $0.2
The nominal strength, Rn , shall be determined as follows: When the concentrated force to be resisted is applied at a distance from the member end that is greater than the depth of the member d,
R" =(Sk+N)1",.,)", 2.
(510. I 0-2)
When the concentrated force to be resisted is applied at a distance from the member end that is less than or equal to the depth of the member d,
R" = (2.5k
-I-
N )1"),,,,/ '"
(510.10-3)
where
k . FyII'
= distance from ouler face of the flange to the web toe of the fillet, mm = specified minimum yield stress of the web,
MPa N
'I<'
Q=150(AS~
¢=IOO(LliFlJ
1.
EF),,,I J
(510.10-4)
This section applies to single-concentrated forces and both components of double-concentrated forces. The available strength for the limit state of web local yielding shall be determined as follows:
Q=200(AS~
The nominal strength, Rn , shall be determined as follows:
When the concentrated force to be resisted is applied at a distance from the member end that is less than 10 I! , H'I shall be reduced by 50 percent.
510.10.2 Web Local Yielding
5·95
When required, a pair of transverse stiffeners OJ' a doubler plate shall be provided.
= thickness of the loaded flange, mm
If
::::;
Steel and Metal
= length of bearing (not less than k for end beam reactions), mm National Structural Code of the Philippines 6'" Edition Votume 1
(51O.10-5a)
5·96
CHAPTEH 5 . Steel and Melals
b. For NIt! > 0.2 II"
=-C,I~.f1 -2h
[0.4(hll",)'] --
(5 10. I 0-
Il bl
7) b. por, (h/ I,.: (5 1O. 10-5b)
XI/b I»
1.7. the limit stille of web sidesway
buckling does not apply.
where
When the required strength of the web ex.ceeds the ,wailable strength. local lateral bracing shall be provided at bOlh flanges althe point of application of Ihe concentf3tcd forces.
= overall depth of the member, mm
d
= flange Ihi ck nc~s. mm
If
When required. a transverse stiffener, or pair of transverse
stiffeners, or a doubler plate extending at Icasl one-half Ihe
In Equations 510.10-6 definitions apply:
and
510.10-7,
Ihe
following
deplh of Ihe web shall be provided . hf
510.10.4 Web Sidesway Buckling
C,
This Section applies only to compressive singlc-colltcnl nllcd forces 'Ipplied to members where relative lateral movemclll between the loaded compression Oangc and lhe tension flange is not restrained at the point of application of lhe concentrated force .
"
The available strength of the web shall be determined as follows:
¢=0.8S(LRFQ
Q = 1.76(ASD)
The nominal strength , R,p for the limit state of web sidcsway buckJ ing shall be dClcnnined as follows: if the compression flange is restrained against rotation:
a.
For (1l/ l w XI/b f )5,2.3
C'I~.r/[ {h l.. )3]
R = -2 - 1+0. -l -
"h
b.
For
I/bl
10" MPa when 1.1"
User Note: For detenninalion of adequalc restraint, ref~~1!r Appendix A-6. -:.;
510.10.5 Web Compression Buckling This Scction applies to a pair of compressive singJcconcentrated forces or the compressive components in a pair of (510. 10-6)
(II/I .. 'N/b f )> 2.3,lhe limit slale of web sidesway
double-concenlrated forces, applied at bolh flanges of a member at the same location .
TI1C available strength for the limit slatc of web local buckling shall be detennined as follows:
buckling does not apply.
When the required slrengUl of (he web exceeds the available strength, local lateral bracing shall be provided at the tension nangc or either a pair of transverse stillcners or a doubler plate shall be provided. I.
If I •.
= nangc widlh, 111111 .
= 6.62 X
If the compression flange is not restrained against rotation:
(510.10-8)
R"
¢=090(LRFQ
0. = 1.67 (ASD)
When the pair of concentrated compressive forces [0 be resisted is applied at a distance from the member end (hat is less Ihan dl2,
R" shall be reduced by 50 percenl.
When required, a single transverse stiffener, a pair of transverse stiffeners, or a doubler plate extending the fuIl deplh of the web shall be provided. Association of Structural Engineers of the Philippines
CHAPTEH 5
510.10.6 Web I'II/IC I Zone Shear
Steel and Metal
5·91
This section appli es to double-concentrated forces applied In one or bo th na ngcs of a member al lhc same locati on.
When required. doubler piate(s) or a pair of diagonal stiffeners 511<111 be provided withi n the boumhtries the rigid conncction whose webs lie in a common plane.
The ava i l~l bl c strength of the web panel zone for the li mit state ofshc.u' yielding shall be de termined as foll ows:
Sec Section 5 I 0. 10.9 for doubler plale design req uiremen ts.
';
¢ =O.90(LRFLj
Q = 1.67 (A SI~
When lh (~ '.! ffcCI o f panel-zone deformat ion on frame sf{Jbilil), i.\' not consider ed ill rhe allaly.\';s:
510,10,7 Unframed Ends of Hearns and Girders At unframed ends of beams and girders not otherwise restrained aga inst rotati on about th eir longitudinal axes, a pai r of tnlllsversc st iffeners. ex tend ing the fuJI depth of the web, shall be provided,
For Pr S O.4 P...
510,10.8 Add itional
The Ilomina! strength, R /I shall be determined as follows: I.
<.1.
Stiffener Requirements
for
ConcentraCed Forces
R" = O.60F,.dJ '" b.
Fo r p ,
(5 10 10-9)
> O.4Pr (510.1- 10)
J.
When
frame
stability,
incl uding
pl astic panel-zone
Stiffeners required to rcsist tensile conccntrated forces shall be designcU in accordan ce with th e requirements of Section 504 and welded to the loaded flange and the web. The welds 10 the flange shall be sized for the difference between the required strength and avail ablc limit stale strength. The sti ffe ner to web welds shall be sized to transfer to the web the algebraic difference in tensi le force at the ends of the stiffener.
defonnation. is considered in the anal ys is:
a. For p, :.sO. 75Pr
(510_10- 11 ) b . Fo r p ,
>
0_ 75P,
Stiffeners required to resist compressive concentrated forces shall be designed in accordance with the requirements in Secti ons 505,6 .2 and 5 10.4,4 and shall either bear on or be welded to the loaded fl ange and welded to the web. The we lds 10 the nange shal l be sized for the difference between the required strcngth and the applicable li mit stale strength. The weld to the web shall be sized to transfer to the web the algebraic difference in compression fo rce at (he ends of the stiffener. For fitted bearing stiffeners. sec Section 5 10.7. Tn.1Ilsvcrse full depth bearing stiffeners for co mpressi vc forces il pplicd to a beam or plate girder flangc(s) shall be designed as ax iall y co mpressed members (co!unUls) in accordanc(". with the requirements of Sections 505.6.2 and
In Eq u3Iions 510. 10-9 through 5 10_I 0- 12, the followi ng definitions appl y: A 1;<1
db de
F.I· P, P,
P,.
1\ Ie!
t".
mm 2,
= column cross-sectional area, = width of column fl ange, mm. :;:;; beam depth, mill. := column dept h, mm. := specified mi ni mum yield stress of the column web. MP._ = P y,N (LRFD ) = O.6P y.N (AS D) := required strength, N. := FyA ,axial yield ~ trc n g lh of th e co lumn , N. := thi ckness of th e column fl ange, mill . := coJ umn web thi ckness, 111m.
51Oo4A.
The member properties shall be determin ed using an effective length of O.75h and a cross section composed of two stiffeners and a strip of the web having a width of 2St at intcrior stiffeners and 121 at the ends of members. TIle weld connecti ng full depth bearing stiffeners to the web shal l be sized to transmit tile differcnce in compressive force at each of the stiffeners to the wel>. Tnlllsvc rse :tnd diagollal stiffen crs shall compl y with the following additional criteria: I.
The width of each stiffener pl us o lle ~ hal f the thickness of the column web shall not be less than one-third of the width of the Oange or moment connection plate deli vering the co ncentratcd force.
2.
TIle thi ckness of a stiffener shaH not be less than onchalf the thi ckness of thc flangc or moment connecti on
National Structural Code of the PI1ili ppines 6'" Edition Volume 1
!j·9S
CHAPTER 5 . Steet and Meta ts
plate del ivering the concclllfiucd load, and grea ter tlwn or equal 10 the width divided by 15 .
3.
Transverse stiffeners shall extend it mi nimul1I o f ollehal f the dept h of the member except as required in 5 10.10.5 and 5 10.10.7.
510.10.9 Add itio nal
Concentrated
Doubler
Plate
for
Forces
Doubler plmes required for compression strength shall be designed in accordance with Ihe requirement s o f Section 505. Doubler plates required for tensi le strenglh shall be designed in accordance with the requirements of Section 504 . Doubl er plates required for shear strength (see Section 510.10.6) shall be design ed in accord ance ' with the pro vis io ns of Section 507.
This Section covers me mbe r strength design consider
511.1 511.2 5 11.3
Concentrated Forces on )-I SS I-ISS-to- HSS Tru ss Connections HSS-Io-HSS Moment Connections
SIl.l Concentrated Forces on IlSS
In additi on, doubler plates shall comply wi th the fo ll owi ng c riteria:
511. 1.1 Definitions of Parameters
I.
The thickness and extent of the doubl er plate s11<111 provide the additionalmalerial necessary to equal or exceed the $(rength requirements .
I!
2.
111e doubler plate shall be welded to devel op the proporti on of the lotal force transmitted to the doubler plate.
Bp J)
Fy Fyp PI( H
N
Ip
:::: overall width o f rcct
511.1.2 L imits of Appl icability 'OlC cri tcria hcrcin are applicab le onl y when the connecl::l'; configuration is within the following limi ts of applicah;l i:::
I.
S trenglh : Fr S 360 Ml'a for /iSS
2.
Ductility: F)/F" S 0 .8 for II SS
3.
Olhcr limits apply for speci fic cri lcrin
511.1.3 Concentrated Force Dis tributed Trans\,("-';<·:i 511.1.3. Criterion for Round IISS Whcn a conccntrated force is di stri buted 1l'lI nsvcrsciy Ie; ; ..... axis of the HSS th e desi gn strength, fRII, Hnd the allowable Association of S truclural Enginee rs of the Philippines
CHAPTEH 5
sifeng lh, Rilln, fOf Ihe limit siale of local yielding shall be dClermined as follows :
Rn = Fy l' 15.5,{ 1 - 0.8IJJpID)JQf ¢ = 0.90 (LRFD)
f}
This limit state need 110 \ be chec ked unless the chord member and brall ch member (connecting clement) have Ih e same widlh
(5 11.1 -1)
= 1.67 (ASD)
(P = 1.0).
c. l . 1 For the limit state of sidewall loca l yielding.
where Qj is given by Equation 5 11. 2 ~ I.
R" = 2F,.r[5k + N]
Additional limits of app li cability arc
l' = 1.0 (LRFD)
i.
0.2 < 8p1V "5 1.0
2.
Dlr S 50 for T·connccl ions and DII
5 · 9!~
SIGl?l and Metal
(511.l-4) f}
= 1.50 (AS)))
where ~ 40 for cross-
co nnections
= o Ulsidc comer radius of Ihe HSS. which is pcrmitlcd to be taken as ! .51 if unknown , mill
k
Sl1.1.3b Criteria for Rectangular HSS When a concen tratcd force is distributed transversely to (he axis of Ihe HSS Ihe design slrength, ¢Rn, and Ihe allowable sire nglh, RnlfJ., shall be the lowest value according to [he limit states of local yielding due to unevcn load dis lrib uti on, shear yielding (punc hing) a nd sidewall strength.
c. I .2 For the limit stat e of sidewall local crippling, in Tconnections,
RII
=1.612[1 + 3N/(H -
3 1)]
(EFy )o"Qf (5 11.1-5)
Additional Ii mils of applicability are
¢= 0.75 (LRFD)
f}
= 2.0 (ASD)
I.
0 .25 < 8,,18 '" 1.0
where Qf is given by Equation
2.
8/1 for Ihe loaded HSS wall '" 35
c.I.3 ror the Iimil slate of sidewa ll local buckling in cross·
It.
For the limit Slate o f locaJ yielding due distribution in the loaded plate,
10
connections,
uneven load
1111 = 14813,{H - 3r)] (EFy )05Qf (51 1. 1-2)
¢ = 0 .95 (LRFD) h.
Q
= 1.58 (ASD)
l' = 0.90 (LRFD)
(5 11.1-6)
n = 1.67 (ASD)
where QJ is given by Equati on 511.2-10.
For Ih e limit state of shear yielding (punching),
R" =0.6/::" I
[211, + 2Bep]
¢ = 0.95 (LRFD)
Q
(511. 1- 3)
= 1.58 (ASD)
where
B"p
Thc nonun iformity of load transfer along the lin e of weld , due to the fl ex ibilit y of Ihe HSS wall in a transverse plate· to·HSS connection, shall be considered in proportioning such welds. This requirement can be satisfied by limi ting th e total effeclive weld lenglh, u, of groove and fill el welds 10 reclangular HSS as follows:
= I OB"/(BIt) ~ Ell'
Thi s limit Slate need nol be c hecked whe n 8p > (13 21), nor when 81' < 0.85 8 . C.
5 1 1.2~lO.
For the limit Sl,lte o f sidewa ll under tens ion loading, the available strength shall be ta ken as the strength for sidewall local yielding. For the limit slale of sidewa ll under compression loading, ava ilable strength shall be taken as the lowe st va lu e obtained ~ccording to th e limit s lales of s id ewall local yieldin g, sidewa ll local c rippling and sidewall local buckling.
Lc = 2[10/(Bh)11(Fy l),{FYfllp)]Bp~ 2B" (511.1-7) where I~
;:; total effective weld length for welds sides of lhe transverse plate, in. (mm)
011
both
In lieu of Equation 511.1-7, this requirement may be satisfied by other rational approaches.
National Structural Code of the Philippines 6'" Edition Volume 1
5-100
CHAPTEI1 5 - Sleel and Melal!;
51 J.J.4 Concenlraled Force Distributed Longitudinally al the Center of the HSS J)iaIlH'tcr or Widlh, and Actin,.; PCrlH!IIdieufar 10 Ihe IISS Axis When a cOllccntrti(cd forcc is di stributed long ttudinall y a long the axis of the HSS a! the center of the HSS diillllc tcr
511.1.6 Concentrated Axial Foret' 011 of a ncctangular HSS with a C "p Plat e.
or widlh , ilnd also acl s perpendicular to Ihe axis directi o n of th e i-ISS (or has a co mponent perpendicu lar to the. axis dircr;ti'}[I o r Ihe HSS), the design slrength, IfJR'I, ,Iud the allowable stre ngth, RIlIn, perpendicl.;J(If to thc IISS axis shall be dClcrmincd fo r Ihe limit state c hord piaslificlHioli as follows .
When (l COIlCClllnllCd force aCls on the end of iI ca pped HSS, and th e force is in the direction of thc HSS axis. the des ign strengt h, ¢JRn, and the al lowa ble strengt h. Rl1/n, 511 •.11 b e dctermined for lhe limi t states o r wall local yielding (due to tcnsile or comprcss ive fo rces) an d wa ll locn l crippling (du e to compressive forces on ly), wi th consideration for shear
of
the
I~ nd
lag, as follows. 511.1.4. Crilerion for Round HSS An additional limit o f applicability is: DII S 50 fo r T·co nnectiolls and 0 11 connec tio ns
.s
Rn = 5.51')' n( I + O.25NID)Q;
tF 0.90 (LRFD)
40 fo r cross-
(5 11 . 1-8)
n = 1.67 (ASD)
where Q/ is given by Equation 511.2-1.
If (SIp + N) ?: B, the ava ilable Slrength of the I-lSS is co mputed by summing th e contribulion s of all four HSS
walls. If (SIp + N) < /3, th e available strength of Ihe HSS is co mputcd by summing (he co ntributions of thc two walls
SI!.1.4b Criterion for Rectangul ar HSS An I1ddilional limit of applicability is :
into which the load is di stributed. a.
8/1 for the loaded HSS wall" 40
For the limit stale o r wall local yielding, ror one wall.
R. = 1',. 1[511' + N)
R. = [/'>" 2ItI - Iplli») [2NIB + 4(1 - IP/iJ)°·' Qj] (5 11.1-9)
¢ = 1.00 (LRFD)
¢
=1.00 (LRFD )
f)
= 1.50 (AS D)
b.
~
BI',. 1
n
(5 11.1-1 J)
=1.50 (ASD)
For the lim it stale of wall local c rippling. for one wall,
where
Qf= ( I - U2)o , (511.1 -12)
V ·is given by Equalion 511.2-12
ifF' 0.75 (LRFD) 511.1.5 Concenlrated Force Distributed Longitudinally at the Center of Ihe HSS Width, and Acting Parallel to the H SS Axis When it conce ntrated rorce is di stributed 10 ngilUdin a il y alon g the axis of a rectangular HSS, and a lso aCls parallel bUI eccentric to the ax is direc ti on of the member, the connection shall be verified as fo]lows: Fyptp ~ Ful
(5 11.1 -10)
Association of Structura l Engineers of Ihe Pllilippin es
n
=2.00 (ASD)
CHAPTI:. n ~)
StGel nnd Metal
511.2 HSS·to·lISS Truss Connections
511 .2. 1 Definitions of Parameters
IISS-(() - I-fSS truss connections
IJ
th at cons ist of one or morc branch members lhal afC directly
welded 10 II cominu.ous chord that passes through the connection and s hall be classified us follows :
J.
When the punching load (Pr sinfJ) in a brandl memher is equilibrated by beam shell f in the dlOro member, the connecti on shall be classified as a T-connection when the branch is perpendicular to the chord and it Yconnection otherwise.
2.
When the punching load (Pr sin8) in a branch member is essentially equilibraled (wi lhin 20 percenl ) by load s in other branch member(s) on the same side of the connection, the connection shall be classified as a Kco nnection_ The relevant gap is between lhe pJimClry branch members whose load s equilibrate. An Nconnectio n can be considered as a lype of K connec tio n.
IJb
connection, mill ;;- out side diamc ler o r round HSS main member,·
Db
= olltside diam eter of round HSS branch member,
E
;:;cccenlricity in a truss connection , posili ve being away from Ih e branches, mm ;:; specified minimum yield stress of HSS main member matcrial , MPa ;:; specified min imu m yie ld stress of HSS branch mcmber mat eri al. MPa ;:; specified minimum (en sile st rength of HSS material, MPa ;:; gap between lUes of branch members in a ga pped K-conncctioll, neglecting the: welds , mm = overa ll height of rectangular HSS main member, measured ill the plane of thc co nnecti on, mill == overall hei ght of rectangular HSS branc h member, measured in the plane of the connection, mm ;:; design wall thickness of HSS main member, mm ;:; design wall thickness of HSS branch member,
111111
!lUll
Fy I'rb
Fu g
3.
4.
';; 'J'., ,
When the punching load CPr sill fJ) is transmitted through the chord member and is equilibrated by branch member(s) 011 the opposite side, the connection shall be classified as a cross-connection. When a conn ection has more than two primary branch members or branch me mbers in more than one plane, the co nn ec ti on sha ll be c lassified as a general or Inulliplanar connection.
1·/
lib
, Ib
mill
f3
When branch members tran smit part of their lo ad as K connections and pan o f their load as T-, Y -, or crossconnecti ons, the nontinaI strength shall be de termined by interpolatio n all the proponi on of eac h in total.
For the purposes of thi s Specification, the cen terJincs of branch me mbers and chord members shall lie in a co mmon plane. Rectangular HSS conneclions are furth er limited to have all members oriented with walls parall e l to the plane. For trusses that are made wi th HSS that are connected by welding branch members 10 chord me mbers, eccentricities w ithin the limits of applicability are p.ermitted wi th o ut consideration <;>f th e re sultin g moments for the design of the con necti on.
= ove rall width of rectangula r I-ISS milin membcr, measured 90 deg rees to th e pl ane of the (;oll llection. m ill ;:; overall widlh of rc(;wngular HSS branch member, measured 1)0 degrees 10 tile plan e of the
D
Us~r Noti'! .kK.~iii)~Ii\)fi\YiIh 'oii~'brancIi ¢!Jle.ri!ji.¢ular to liie'cbord,is often Cl!liOd .anN-'comi.,qUoniY ;,:'
5-10 1
r '1
o S
::: the width rat io; th e ratio of branch diameter to c hord di ameter =- DblD (or rou nd HSS; the ratio of overall branch width to chord widlh ;:; Bbl B for rectangular HSS ;:; the effect ive width i'Cilio; lhe Slim of the perimeters of the two branch members in a K· connection divided by eight limes the chord width :;::: the c hord slenderness ratio; the ratio of one-half the diameter 10 the 'wall thickness = DI2I [o r round HSS; the ratio o[ one·hal[ the width to wall thickness:;::: Bnl for rec tangular HSS = the load length parameter. applicable only to rectangular IISS; Ihe ralio of Ihe lenglh of contact of the branc h with the chord in the plane of the connection to the chord width ;:; NIB. where N:: I1blsi nO =- acute .angle bet ween the branc h and c hord (degrees) = lhe gnp ratio; the rafi o of th e gap between fil e bran chcs o f a gapped K connection to lhe width of Ihe chord = 8/B for rectan gular HSS
National Structural Code o f the Philippines 6'" Edilion Volu me 1
5· 102
CHAPTER 5 . Sleel and Melals
511 .2.2 C rileria for Round HSS
3.
The in teraction of stress due to chord member forces and local branch connection forces shall be incorporated through the chord-s tress in teraC li on parameter Q/.
Tension branch wall slenderness: mti o of diameter to willi th ick ness less than or equa l to 50
4.
Compression branch wall slenderness: ratio o f diameter to wall thickness less th an or equal to O.OSEIFy
Vlhc n the chord is in tension,
5.
Width nuio: 0.2 < DhID:::: 1.0 in general. and 0.4 DblD ~ 1.0 for gapped K-connections
6.
If a gap connccti on: g grcalcr thall or equal of the branch wall thi ck nesses
7.
If an overlap connecti on: 25%:5 Ov ~ 100%, where 0" = (qlp)xlOO%. P is Ihe projected length of lhe overlappi ng branch on the chord; q is Ihe overlap length measured along the con necting face of the cho rd beneath the two branches. For overl ap con nect ions, the larger (or if equal diameter, the thicke r) branch is a '·th ru member" connected direct ly to the chord.
8.
Branc h thickness ratio for overlap con necti ons: thic kness of overlappin g branch to be less th an or equal (0 Ihe thickness of the overlapped branch
9.
Srrenglh: F,.:s: 360 MPa for chord and branches
0 =I When the chord is in compression,
0= 1.0 -
0.3U (J + U)
(511.2-1)
where U is the utilization ratio given by
V=
IP,IA,F~
+ M,ISF,I
(51 1.2-2)
where
P,
= required axial stren gth in chord, N; for K-conncctions, P, is to be determined on the side of til e j oin I Ihat has the iowercomprcssion stress (lower U) =required flexural streng th in chord, N-m m = chord gross area, mm 2 =available stress, MPa
M,
Ag I-",
= chord elasti c section modulus, mm
S
= Pu =:. req uired axial strength in chord, using LRFD load combinations, N
M,
::::: Mu ::::: required flexural strength in chord, using LRFD load combinations, N·mm = Fy , MP.
Fc
0.8
Sll.2.2b Branches with Axial Loads in T·, y ~ an d Cross·Connections For T· and y. connections, (he design slrength of the branch ~Pn, or the allowable strength of the branch, P,,/fl shall be the lower value obtaincd according [0 the limit stales o[ chord plastification and shear yielding (punching).
I.
For the limit Siale of chord ptastificati on in connections,
T~
and Y-
P"sin9 = F; ('[3.1 + 15.6/fJ-1'·'QJ
For design according 10 Seclion 502.3.4 (ASD):
p,
~
the sum
3
Fo r design according 10 Secli on 502.3.3 (LRFD): p,
10. Ductilily: 1-",.1 F"
(0
~
(511.2- 3) ::::: Pa::::: required ax ial strength in chord, usin g AS!) ,
::::: Mo::::: requi red flexural strength in chord, using AS D load combinati ons, N·mm
n = 1. 67 (AS D)
¢ = 0.90 (LRFD )
load combinations, N
2.
For Ihe limit Slale of shear yielding (punching).
Pn = O. 6Fy mDb[(J + si nS)/2sin'S]
F, = 0.6 Fy , MP. ¢= 0.95 (LRFD)
511.2.2a Limils of Applicability
.Q = I. 58 (AS D)
The criteria herein arc appl icable o nl y when the connection configurati on is within lhe foll ow ing limits of applicabilit y:
This Iimil Slale need nol he checked when
loint eccentricity: -0.55D $ c $ O.2SD, where D is the
3.
c hord diameter and c is positive away from the branches
fJ> ( I -
ror the lim it sta le of chord plaslificati on in cross-
conneclions,
P"si nS = 1',",, [5.7/(1 - O.81,8)]QJ
I.
Branch angl e: 9 ;, 30'
2.
Chord wall slenderness: ratio of diameter (0 wall thickness less Ihan or equal 10 50 for T -, Y - and Kconnectio ns ; less th an or equal (0 40 for crossconnecti ons
Ify).
if = 0.90 (LRFD)
Association of Structural Engineers of the Pililippines
.Q
(511 .2-:,)
= 1.67 (ASD)
CHA PTE:I ~
S
S!eel and Meta!
511.2.2(.' Branchl's wi lit Axial Loads in K-C onnections
For K COllll ct'lions, the des ign s lrl~llglh of the bmnch, ¢P.. , iUH ll hl' ;llIowabh.' s tfl'lll! th of the brand l, I',,/n, shall he the lower vill uc ohtaincd a(.:(;or
hlJ" the limit
s[illl~
of chord plastifi<.'a tioll,
h I !'
where
/'
= req uired ax ial strength in chord, N. foor gapped K-conllections, 1', is to be determined on the side of the jOil)! thaI has the higher compression stress (higher U). :;: required flexural strength in chord, N-mlll :;: chord gross area, mrnl = available stress, MPa :;; chord clastic sec ti on mod ul us, mml
1\"
the nllllprcssion branch :
F,. S
!'.sine = 1"./,12.0 + I U3D,/D]Q,Q,
For design accord ing to Sec tion 502.3.3 (LRF D): (51 12-6)
where
(SI1.2-12)
M,
n = 1.67 (ASD)
¢ = () 9() (I.RFD)
J)"
refers to the co mpression branch only,
5· 10J
;:;:: P II = required axial st rength in chord,
using LRFD load combinations, N :;; Mu ;;:;; required flexural strength in chord. using .LRFD load co mbinations, N-nliTI = F.. MPa
P,
Mr
r. (511.2· 7)
For des ign accordi ng to Section 502.3.4 (ASD):
In gapped connectiolls, g (meas ufed along the crown of" the chord neglecting we ld dimensions ) is positive. In overlapped connections, X is negative and eq uals q. For the tension bnwch .
(5 11 2-8)
2.
POf the limi t state of shear yielding {punching} in gapped K-connectioJls, !,,, =
O. 6Fr mIJ;,1 (I ,. sinG)i2sin 'e]
¢ = 0.95 (LRFD)
(SI I.2-9)
n = 1.58 (ASD)
M,
1',
When the chord is in tension,
1.
Bntllch angle:
3.
or overall wall width to thickness less than or equ al to 35 for gapped Kcon nectio ns and T·, y . and cross-connections; I e..~s than or equ al to 30 for overlapped K-connections
5.
Compression branch wall slenderness: ratio of overa ll wall widlh 10 Ihi c kness less than or equal 10 1.2S(J::IF r,,)05 and also less than 35 for gapped Kconnections and T ~, Y- and cross·connections; less than or cq llalto 1.1 (/'.11;\./))°.5 for ove rlapped K,colln ecliolls
6.
Width ratio: ratio of overall wall width of branch to overall wa ll width of chord greater than or equal 10 0.25 for T-, Y-, cross- and overlapped K-conncctions; greater than or equal 10 0,35 for gapped K-connec tiolls
7.
Aspect ratio: 0.5
When the chord is in compression in gapped Kcon nectills,
4.
(S I1. 2- 11 )
Chord wall slenderness: rati o
4 . Te nsion branch wall slenderness: ratio of overall wall width 10 thickness less than OJ' equal to 35
When the chord is in comp ression ill T -. )' -, and crosscon nections,
0= I. 3 - 0.4 U!Jl
e ~ 30 ,
2.
(S II2 · IO)
3.
Joint ecce ntricity: -O.S5H $ e 5 0.251-1, wh ere H is the
chord depth and e is posi ti ve away from th e branches
Qr= I 2.
Limits of Applicability
The cri teria herein arc applic ab le only w hen the connection configuratio n i s within the fo llowi ng limits:
S11.2.3 Criteria for Rectangular HSS The interaction of SU'cst,; due (0 chord member forces and local branch connection forces shall be incorporated throu gh the chord-s tress in terac tion parameter Qr. I.
:;: P"
511.2.3~
PI/sinS = (P"si nS) com press ion branch
=
req uired axial strength in chord, usin g ASD load combinations, N :::: Mil :::; required flexural strength in chord, usi ng ASD load combinations, N-mm = 0.61', . MPa
P,
$
ratio of dcpth to width
Where U is the utili zation ratio given by th
National Structural Code of the Philippines G Edition Volum e 1
$
2.0
~j
J(Jtl
C HAPTUi 5 · Sleel and Metals
~.
Overlap: 25% ~ u,· $ 100%, where (),. = ('III') x 100%. {J i!-i the..: projCl:tco length or the overlapping bmnch on the dlOrd ; q i!-i the overlap length measured a long the L'onnec ti ng face of the chord beneath the two brallches. For overlap connections. the larger (or if equal width, the thicker) branch is a "thru member" connected directly to the chord
9.
Branch width ratio for overlap connec tions: ratio of overall wall widt h of overl apping bra nch to ove rall wall widt h of overlapped branch greater than or eqll"sI to 0.75
bmllchcs in compression shall be taken as the lower of the strcngths for sidewall 10c:1I yiel ding and sidewa ll local crippling. For Cf(1s:H;on nccli ons with a branch angle less than 90 degrees. all additional check fo r c hord sidcwf.l1I she'lr failure mu st be made ill tteCOrdilllcc wi th Sec ti on 507.5.
This limit state need not be checked unless the chord member and branc h member have 'he same width (B = 1.0).
For the limit state of loca l yield ing. P "sin9 =
'0. Branch thic kness ratio for overlap con nec ti ons: thic kness o f overlapping branc h to be less than o r equld to the thic kness of the overlapped branch
II . Strengt h:
I'~\' S;
1.50 (ASD)
where
= outside
comer radius of the I-:I SS, which j~i permilted to be taken as f .sf if unknown. mm = bea ring length th e load, ptlrallel to the
k
12. Duc lilil y: 1',.11'" $ 0.8
or
N
13. Ot her limits apply for specific criteria a.
51 1.2.3b Bntnehcs with Axial Loads in '1'-, yand Cross· Connections For T·, Y~, and cross-connections, the design stre ngth of the
For the limit stale or sidewa ll 10CHI cri ppling, in T- and Y-connections,
P" sine = 1.61'[ 1 + 3N I(H - 3t))(EF)· )05 Qf (511.2-16)
¢=0.75 (LRFD)
b.
n = 2.00 (ASD)
For the limit state of sidewall local c rippling in crossconnections.
P" sine
0.25. I.
(5 11.2-15)
n=
$= 1.00 (LRFD)
360 M Pa for chord and branc hes
brun ch, rpPII, or lhe allowable strength of the bran c h, P,/fl, shall be the lowest value obtained accordin g to the limit stales of chord wall piastificati on, shear yi elding (punching), sidewall strength and local yielding due to uneve n lo ad distribution. In additi on to the l.imits of applicability in Seeli on 5 11.2.3a, fJ shall not be less Ihall
2Fy l[Sk + NI
= [4 81'/(H -
31))(EF)' )05 Q; (51 1.2- 17)
For the li mit slale of c hord wall plastifi cation. P"sill O = 1', 1212'1/(1 -
fJJ + 4/(1 - fJJ°.lJQJ ($ 11.2- 13)
t/J=
1.00 (lRFD)
¢ = 0.90 (LRFD)
4.
n= 1.67 (ASD)
For the lim it state of loca l yielding due to uneven load distribution,
P,,= F),blb[2Hb+ 2b
fJ= 1.50 (AS D)
(5 1 L2·I g)
This limit'state need not be checked when f3 > 0.85. 2.
¢=0.95 (LRFD)
For the limil stale of shear yielding (punching), l'"sinO = 0.61'" 8[2'1+ 2fJw,,)
¢=0.95 (LRFD)
(5 11.2-14)
fJ= 1.58 (ASD)
In Equation 5 11. 2- 14 , the effect ive out s ide punc hing
n = I. 58 (ASD)
wherc bro , = I I O/(BII)JI F, II(F" ,lh)]B h ~ B"
(5 11 ) is-')
Th is limit state need not be c hecked w hen B< 0.85.
jlillTlmctc r /In,, = Sj31y slm ll not exceed P This lim it state need not be c hecked when
f3 > (l - l /y), nor
when fJ < 0.85 and BII" 10. 3.
For the st ren gth available glale of
limit sl ate of sidewall strength, [h e available for branches in tension shall be take n. as the stre ngth for sidewall local yielding. For the limil sidewall s(renglh, the available strenglh for
Sl1.2.3c Branches wilh Axial Loads in Gapped K Connections . For gapped K-co llncc!ions, the design strength oj' !l branch, ¢P n , or th e allowable streng th of the branch, p" 1/( shall be the lowest value obtained according to th<.· states of chord wall plaSlificati on, shear yi , idlfJ,l', (pullching), shear yielding and local yielding due to Uil(:yeU
Associati on o f Structural Engineers of tl18 Philippines
C HAPTU'~~)
Slewl and Metal
load distribution. In additi o n to (he limils of i1pplic,abil ily in SCl:tioll K23a. the following limits shall apply:
lh 11/ ? O. I ; . Y/50
2.
/hl ? 0.35
).
:5 0. 5( I - fl.t!)
4.
Gap : g greater tl1
5.
Th e smaller fib > 0.63 times the larger 8/,
(511.2·24 )
P,,::: f<~I'I"
i'" sinO ~ 1',. t'19.8fJ,IiY'·'JQr
0.95 (LRFD)
~
(5 11.2·2 1)
lib,
;: :;: overall branch widt h of the overlapping branch ,
B /JI
;::
Fy/li
5pccificd minimum yield stress of th e overlappin g branch material, MPa ::: specified minimum yield stress orthe overlapped . branch material, MPa
111m
FYhi
For the limit stale of shear yielding of the chord in the gap, available strength shall be checked in accordance wi th Section 507.5. Thi s limi t Slale need only be checked if the chord is not square. For th e limit state of local yielding due to un eve n load distribution, i'" ~ F,.blb[2f1" + IJ" + h,,,, - 4th]
¢ ~ 0.95 (LRFD )
Q ~
(511.2· 22)
1.58 (ASD)
overall branch width of Ihe overlapped branch.
mm
Thi s limil Slate need only be checked jf BiJ < (8 - 2t) or the branch is not square .
b.
b"",.
(5 112·28)
1.'i8 (ASD)
In the ,lbovc cqlJ
~.
(5 1! .2·25)
is the effeclive wid lh oflhe branch face welded 10 the chord. ~ [ I O!(BIt)J[ (1')" ,Y( F,bi I., ) ]Bbi 00 Bb, (51 1.2·27) is the effective width of the branch face welded (Q the overlapped brace. ~ [ I Of(Bbj !tbi )]I (F""i 110, YC!'~'bi I", )] Bbi :5 Bbi
b,.",
Q ~ 1.67 (ASD)
Q
+ b~m + b..",. J
where
foor the limit state of shear yieldi ng (punch in g) ,
¢~
4t/II
For the ove rl apping br'lf)ch. and for overlap 80% :::: 0,. ~ 100% measured with re spect to the overlapping branch,
(5 11.2.20)
P" sinO ~ 0.6F,. 1 131 211 + fJ + ~"''' ]
[2Hhi -
fhi
(51 1.2·26)
For the li mit state of chord wall plastification ,
a.
I 0:)
POI" the overla pping bntnch, and for overlap 50P/v ~ 0 ,. < 80% measu red wit h rcspeci 10 the overlapping branch,
I.
¢ ~ 0.90 (LRFD)
~) .
;:::;:
If"
= overall depth of the overlapping branch. nun
Ib/
;::
114
= thickness of the overlapped br~nc h , mm
Ihickness of th e overlapping branch, mm
For the overlap ped branch. Pn shall not exceed PII of the overlapping bra nch. calculated using Equation 511.2-24 , 511.2·25. or 5 11.2·26, as applicable, multip lied by the
factor (A bj Fybj lA b; F yui), where
where b,,,, =[I O!(I)!t)II F,. 1!(r,.iJlb) ]13" 00 13"
(5 1 1.2·23)
This limi l stale need only be checked if (he branch is not square or Blr < 15.
511.2.3d llranches with Axial Loads in Overlapped K - Connections For overlapped K-connccti ons, the design strength of the branch, (1P". or the allowab le strength of the branch, PI/fl , shall be det ermined from the lim it slate of local yielding due to uneven 10ild di stril>lllioll ,
F
511.2.3e Welds to llra nches The nonuniformi ty of load tran sfer along the line of weld, due to differences in relative flexibility of HSS wall s in HSS-Io- HSS conn ectio ns, shall be considered in proportionin g such welds. This can be considered by limiting the total effective weld length , 1..<. of groove and fillet welds (o rectangular I-l SS as follows: I.
().9S (LR FD)
In T-, Y - an d cross-connecti ons. for 0
~
50 degrees
Q ~ 1.58 (AS D)
For the overlapping branch, and for overlap 25% ~ 0 1' :S 50% measured with respect to the overl apping branch.
P"
= cross-secti onal area of the overlapping branch ;:: cross-secti onal area of the overlapped branch
AI,,' Abj
~ F,,, lbi [(O,/50)(2f1bi - 41bi)
2 (11" - 1.21,, ) L, = . --.-- - - + (/J" ·- 1.21,,) Sill
for
e
e? 60 degrees
+ b",; + b,... ]
National Structural Code of tl1e Philippines 6'11 Edition Volume 1
(511.2·29)
~i
C HAl'rEI~
lOG
5 . Steel and Malals
2( 11" -- 1.2,,, )
(5 11 .2-30)
L e, .----.--.---.-- .
'"
sin (}
Lincilf inlcrpnhui OIl shall bc-used ofe hctwccn50a nd 60 degrees. 2.
t t)
delermine J..,.. for va lues
In ,gapped K·coll neclions, arou nd each branch, for e $ 50 degrees 2(11 , -1.2,,) . +2(11,,- 1.2,.)
0
Sill
for
I I
(511.2-31)
e ;, 60 degree s _2(11,,-1.2,,)
L,.-
.
510
8
+
(8
2
1,-1 " 11)
r (5 11.2-32)
Linc;lr inLCrpoli.llion shall be used 10 dCLcrmine /...,. for va lues of a between 50 and 60 degrees. In lieu of the above criteri
1.
2.
jJ
As a T·connection when there is one branch and it is perpendicular to the chord and as it Y-connection when there is one br:lnch but nOLperpendic ular to (he chord.
"
o
511.3.2 Crileri" fo r Round HSS The interaction of stress due to chord mcmber forces n.nd local branch connection forces shall be incorpormed through rhe chord -);trcss interaction parameter Qr.
When the chord is in tension.
Qr = 1 Whcn the chord is in compression ,
As a cross-c:onnec tio n wh cnlhcrc is a branch 0 11 eac h (opposite) side of the chord .
For the purposes of th is Specification, the centcrlines of the branch member(s) and the chord member shall lie ill a common plane. 511.3.1 Definitions or Param eters B :;:: overall width of rectangular HSS main member, measured 90 degrees LO the pl.me of the con nec tioll, mm E'l :;:: overall width of rectangular HSS bra nch mcm be r, mcm;;u red 90 degrees to [he plane of thc con nec tion. nUll /J :;:: outside di
Db
mm ::: outside diameter of round HSS branch member. mm
Fy
=:
specified minimum yield stress of HSS main
FI'/J
:::
memOcr, MPil specified minimum yield stress of HSS branch member, MPa
:;:: ultimatc st rength of HSS mem ber. MP" :;:: overall he ight of rec tan gular IISS main ml~ llIbn. m ca~u rcd in the plan e or th e connct..:liDIl. rllill :=: overall hcight o\" rccwngul ar !-I SS branch membcr. 111c:lsurcd in the plane of lilc connecti()U , mill :;:: dcsign wall thickncss or IISS m of ove rall hru llch widt h to dlOrd wi(lI h = IJbli; foJ' rec tan gular HSS :;;: thc chord slendern ess ratio: the ntlio of o nc~ha ir Ihe diameter to Ihe Wil li thic kn ess::; 012, for round HSS; Ihe rati o of one-half the width h' wa ll th ickness = 812, for rectangular HSS :;:: the load length paramcter. applicable only 10 rectangular HSS; the ratio of the length of contact of the branch wilh the chord in the plane of the connection 10 the chord width ::; NIB, where N::; Ht/sine :=: acule angle betwccn the branch and cho; ;; (degrees)
Qr= 1.0 - O.JU(1 + U)
(51 U "
where U is the uti li zati on ratio gi vcn by U= IP,IA, F, + M,ISF, I
where 1', M,
A, F, S
:;:: requi red axial strength in chord. N :::: required Oexural strength in chord. N 2 :;:: chord gross area. mill :::: 'lva ilablc stress. MJ>'I :;:: chord clasti c section modulus, mil'"
Association of Structural Engineers of the Philippines
111111
CHAPTE.n~)
For design according :=
M,
Po.
:::.0
:::: M I, : : :
to
S!e<::1
511.3.2c Branches with Out-of-Plane Bending Moments in '1'-, Y- and Cross-Connections
Section 502.3.3 (LRFD):
required axial strength ill chord, using LRFD load combinations, N required llexural strength in chord, using LRFD load combinations, N-J11l11
:::: Fl' , MPa
The design strength, ¢Mil, and the allowable strength, MnlQ,
shalt be the lowest value obtained according to the limit states of chord plastification and shear yielding (punching). I.
For the limit state of chord plastification,
M"sin8
= F),I'Db[3.0/(1
- 0.81,8)JQr
For design according to Section 502.3.4 (ASD): 1',
M,
Fc
:)-101'
(511.3-5)
= PI!
required axial strength in chord, using ASD load combinations, N :0: M" required llcxural strength in chord, using ASD load combinations, N-mm = 0.6F,.. Mra
¢ = 0.90 (LRFD) 2.
For the limit state of shear yielding (punching), M" = O.6/S.IDb'[(3 + sinG)l4sin'G)QJ
¢ = 0.95 (LRFD)
511.3.2" Limits of Applicability The criteria herein are applicable only when the connection configuration is within the foHowing limits of applicability:
e 2 30·
fJ = 1.67 (ASD)
fJ =
(511.3-6)
1.58 (ASD)
This limit state need not be checked when
fJ > (l
- l/y).
I.
Branch angle:
2.
Chord wall slenderness: ratio of diameter to wall thickness less than or equal to 50 for T - and Yconnections; less than or equal to 40 for crosscoonections
SI1.3.2d Branches with Combined Bending Moment and Axial Force in T~, Y and Cross - Connections Connections subject to branch axial load, branch in-plane bending moment, and branch out-of-plane bending moment, or any combination of these load effects, should satisfy the following.
3.
Tension branch wall slenderness: ratio of diameter to \\Iall thickness less than or equal to 50
For design according to Section 502.3.3 (LRFD): (P/¢p,) + (M,-iplrf!M,-ip)2 + (M,-oplrjM,-op) " 1.0
4.
Compression branch wall slenderness: ratio of diameter to wall thickness less than or equal to O.OSEIFr
5.
Width ratio: 0.2 < DblD" 1.0
where
6.
Strength: Fy:5 360 MPa for chord and branches
P,
7.
Ductility: FrlFII:5 0.8
(511.3-7)
511.3.2b Branches wilh In-Plane Bending Moments in
T-, y ~ and Cross-Connections The design strength, ¢M", and the allowable strength, M"IfJ, shall be the lowest value obtained according to the limit states of chord plastification and shear yielding (punching). I.
For the limit state of chord plastification, M"sin8
= 5.39F,.I'Y'·SfJ Db QJ
r(F 0.90 (LRFD) 2.
fJ =
=
required axial strength in branch, using LRFD load combinations, N = design strength obtained from Section 51 J .2.2b :0: required in-plane flexural strength in branch, using LRFD load combinations, N-l11m :0: design strength obtained from Section 511.3.2b = required out-of-plane flexural strength in branch, using LRFD load combinations, N-mm = design strength obtained from Section Sl1.3.2c
For design according to Section 502.3.4 (ASD): (511.3-3)
(P,/(P';fl)) + (M,-ipl(M,,-iplfl))' + (M,-opl(M,,-op/Q)) " 1.0
(5113-8)
1.67 (ASD)
where
For the limit state of shear yielding (punching), M" = 0.6F,.ID,,'I(I + 3sinO)l4sin'O)
¢ = 0.95 (LRFD)
8M ,I .ip M r , ofl
::; PI!
(511.3-4)
fJ = 1.58 (ASD)
This limit state need not be checked when fJ> (I -
lly).
P,
= Po
P,/Q
:0:
Mr.;!'
:0:
:::: required axial strength in branch, llsing ASD load combinations, N allowable strength obtained from Section 511.2.2b required in-plane flexural strength in branch, using ASD load combinations, N-mm
National Structural Code of the Philippines 6'h Edition Volume 1
Mn-iplS2=. allowable strength ohwined from Section 511.3.2il Mr·o{) =. required out-of-plane flexural strength in branch, using ASD load combinations, N-Il1!ll MII-ojJ/S2=. allowable strength obtained from Section 511.3.2c
1.25(UF,h)O.5 and also less tll"l1 ::\)
).
Width ratio: ratio of ovcrall wal] width of branch (0 overall wall width of chord greater than or equal to 0.25
6,
Aspect ratio: O.S :S ratio of depth
7.
Strength: Fr S: 360 MPa for chord and branches
5 I 1.3.3 Criteria for Rectangular HSS
~,
Ductility: F/F" ~ O.X
The interaction of" stress due 10 chord member forces and local branch connection forces shall be incorporated through the chord-stress interaction parameter QI~
9.
Other limits apply for specific criteria
Whcn thc chord is in tension,
When the chord is in compression, (51 1.3·9)
QI= (1.3 - OAU!j3):" 1
For the limit state of chord wal! plastification,
J.
+ M, ~)f)
M" = 1',.1'11,,[(11211) + 2I( I - ~)05 + '1/( I - P)[Q{ (511.3·1/)
(5113·10)
¢ = 1.00 (LRFD)
where
P,.
=.
M,
=.
Ag
=.
Fc
=.
S
=.
required axial strength in chord, N required flexural strength in chord, N-mm chord gross area, mm 2 available stress, MPa chord elastic section modulus, mm 3
Pu
M,
MOl
F,
P,.
::; Pa
Mr
=.
F,
;:;;:
Ma ::;
> 0.85.
(511.3·12)
M" = O.5F:t(Hld 5,)2 (3 = 1.50 (AS D)
where for
F,:
::;
I~,.
F:
=.
0.8F,. for
T~connectio!1s
cross~c()[Hlections
This limit state need not be checked when
For design according to Section 502.3.4 (ASD):
f)
For the limit state of sidewal! local yielding,
2.
required axial strength in chord, using LRFD load combinations, N required flexural strength in chord, usingLRFDload combinations, N-mm
= F,., MPa
(3 = 1.50 (ASD)
This limit state need not be checked when
¢ = 1.00 (LRFD) For design according to Section 502.3.3 (LRFD):
P,
:s 2.0
51 I.3.3b Branchcs with In~Plane Bending Momcnts in T~ and Cross-Connections
where U is the utiliz
= IP,/A,r~
width
The design strength, ¢MJl, and the allowable strength, Mil/D., shall be the lowest value obtained according to the limit states of chord \vall plastification, sidewall local yielding and local yielding due to uneven load distribution,
Qr= I
u
to
3.
fJ < 0.85.
For the limit state of local yielding due to uneven load distribution, M" = F,.b[Zb - (I - b,,,;lB,,)B,,li,,l,,j (511.3·13)
required axial strength in chord, using ASD load combinations, N required flexural strength in chord, using ASD load combinations, N~mm
¢= 0.95 (LRFD) (3= 1.58 (ASD)
where
= 0.6F,., MPa
511.3.3a Limits of Applicability The criteria herein are applicable only when the connection configuration is within the following limits: 1.
Branch angle is approximately 90"
2.
Chord wall slenderness: ratio of overall wall width to thickness less than or equal l() 35
3.
Tension branch wall slenderness: ratio of overall wall width to thickness less than or equal to 35
4.
Compression branch wall slenderness: ratio of overall wall width to thickness less than or equal to
/Jeoi
= IIO/(B/t)J[hl/(F,blI,)]B,,$IJt.
Zb
::::: branch plastic section modulus about the axis bending, fnm 3
(511.3·14)
This limit state need not be checked when j3< 0.85.
Association of Structural Engineers of the Philippines
or
Ou(·of-Plane BCIl(ling Momellts in '1'- and Cruss-Connections
51 J .3. 3(' Br:lIlChl'S
with
The design slr(.~ n gl h , ~~M". and Ihe allow'lulc streng th . Mil/P. shall be the lowest va lu e ohtained according to the limit slates of' chord wall plastificat ion, sidcv.l
1,
di slOn i o llltJ failure .
M ,, = ,..,,'10.511b(1 + /J)/(I - /J! +1 2[JIl/,(1 + fJ)I( I-(J}J"'JQr
P,
(JP" M,.w ¢Mu .,1' Mr-.'I'
(511.3-15)
11 = 1.50 (ASD)
8= 1.00 (LRFD)
This lim it stl.1lc need nOI be checked w hen P>
2.
0.85.
For the limit s(fttc of sidewall local yieldin g. M" = F'I(Il-I)(I1/, + 51)
+ (M,.ip/(Mn.ipln.) + (Mr.fI,,!(M'H!pln) 5 J.O (511.3-21)
where P,
;:: P
= required axial strength in bra nch. usi ng
ASD load combinati ons, N = aIlowable st rength obtai ned from Section 5" .2.3b M r.i!' ;:: required in-plane flexural strength in branch, using ASD load combinations, N-mm M".,,)l1 = allowable strength obtained from Section 5 I 1.3.3b M'-hfl = required out-of-plane flexural strength in branch, using ASD load combinat ions, N-mm M" .(1,1Q ;:: allowable strength obtained from Section 5 I 1.3.3e P"IQ
I~\ '
= F ,· for T-COllnCClions
I~r'
= O. SFy for cross -conn ec tions
This limit state need nO{ be checked when
fJ < 0.85.
For the limit state of local yield ing du e to uneven load
distribution,
M" = I',·.lz" - D.5( I t/F 0.95 (LRFD)
= required axia l st rength in br'lIlch. lIsing LRFD load cornbinmions. N ;:: design strength obtaincd from Sec ti on 51 1.2..31> ;:: required in-plane flexural strcngth in branch, using LRFD load co mbinations, N-mm ;:: design strength obi
For design according to Section 502.3.4 (ASD)
(511.3- 16)
where
3.
rpM".""
= PIt
(Pr /( P"I11»
fJ= ISO (AS D)
t/J= 1.00 (LRFD)
+ (M'·"I'/lM1 .. -opJ ::: I.U (51 103·20)
where
For the limit sl ate of c hord w;tl i plastificalioll.
I.
I
(I', I¢I'.. J + (M, ·;pltP-W.. ·;I')
b,,,,18')1B'2II,J
(5 11.3-17)
fJ = 1.58 (ASD)
where (511 .3- 18)
z"
= branch plastic section mod ulus about th e axis of bending. mm)
This limit state need not be checked when 4.
f3 < 0.85.
For the limit state of chord distortional failure. M" = 2F,. I[lib l + [Blil(1l + H)JO.5J
(5 11.3- 19)
¢ = 1.00 (LRFD ) fJ = 1.50 (AS D) This limil stale need nOI be checked for cross-con nections or for T-conllcctiolls if chord distortional failure is . prevented by ot her mea ns.
Sll.3.3d Branches with Comuined Bending Moment and Axial Force in '1'- and Cross-Connections
Con nections subject to brf'lllch axial load, branch in-plane bending moment, and branch out-of- plane bending moment. or any combination of these load effects, should satisfy For design according to Section 502.3.3 (LRFD)
National Structural Code of U,e Philippines 6'" Edition Volume 1
." 5 110
CHAPTUi5 ~ Steel and Metal:,
SE0TION,,512 ~. . 1;. ' : . DESIGN FOR SERVICEABILITY l {. ~'
'rhis Section addresscs s~rvice
General Provisions Olln[)';,
Dcncuions Drift Vibralion
members, the additional denections duc to the shrinkage and creep of the concrete should be considered.
512.4 Drift Drift of a ~trllc ture sh
Wind wlnduced Motion
5 12.5 Vibration
Expansion and COlllraclion
The effect of vibration 011 Ihc comf0l1 of the occupants an,! the fUllction of the Sl ru<.:turc shall be considered. Th~ sou rces of vibration 10 he considered include pedestrian
Connection Slip
512.1 GCII Cr:tI Provisions
loading, vibratin g machinery and o thers identified for t h ~
Serviceability is a sUite in whic h lhe functi on or a building. its appeara nce, maintainability. durabilit y, .. nd comfol1 or it s occupants arc preserved undcr no rmal u S~lgc. Lim iti ng values of structural heha vior for scrviceabi lil y ( rOf' eX
structure.
User Note: Additioii.rinforination on serviceability limit states, senilce' lo.iid;i'lUid appropn~te load cOl1lbin ations for serviceability h!qui!iments' '",an be fou n:d in ' ASCE 7 Appendix' . B ··t,;).nQlehiary. inc ' perfonuan~ requit'emeitts fof~erVi2~abiiilY' In 'iiiis S&tioli :ite consistent with those rCquiieinehtsiSeiVke'loads, as stipulated herein,
''hllii ··'.lts
are those that act on the StructUIC at an arbitr~tY point in time. That is, the appropriate .load combinations are often less severe. than those in ASCE 7, Section 2.4, where the
LRFD load 'combinations are given. 512.2 Camber
Where camber is used to achieve proper position and location of the structure, the magnitude. direction and location of camber shall be specified in the stru ctural drawings.
5 12.6 \.vi nd·lnduced Mo tio n T he effec t of wind·i nd uced mOlion of buildings on the t~olllf()n
of oCCtJP!lJlIS shal l he considered .
512.7 Expansion and Contraction The efrects of th ermal expa nsion and co ntraction of ;1 building shall be co nsidered . Damage 10 bui lding claddiE i~ can c.luse water pe.nc\r:uiotl and Illay lead to corrosio n. 512.8 Conncclion Slip The eerects of conneclion slip s hall he included in ilL; design where slip at bolted connections may cau~ c deformations. tilat impair the serviceability of the structure.
Where appropriate, the co nnection s hall be designed to preclude slip. For the design of sl ip wcriti cal connections sec Sections 510.3.8 and 510.3.9 . User Note: For more infonnation on connection sli p, rer·· to tbe RCSC Specification for Structural Joints Usi" g ASTM A 325 or A490 Bolts.
User NQle: Camber recommendations are provid.ed in the Code of St'!'ru!ar4 Practice for Steel Buildings and Bridges.
512.3 Deflecti ons
DcOcclions ill structural members and stru,ctura i systcms undcr appropriate service load combinations shall !lot impair th e serviceability of the structure. User Note: Conditions to be considered include levelness of floors, alignment 'of structural members, integrity of buililiP8 finishes/ 'and .bther :factors that aJfect tb.e normal u ~ag'e .ai\d f~.i)2iion ofthesti-u~ttire: For composite
Association of Structu ral Enginee rs of the Philippines
C HI\P n~ n !J
SECTION 513
.
.
FABRICATION~' ~~¢rl0N AND ...
~
111
requin::IHcllls of SC1.:tioll 5/0. /.6. Beam cope!'. amI wdds 'H.'cess holes ill Sh
,I
QUALITY CONTit()L ...
Th is Section addn!sscs requirements for shop drawings, fabri cation. shop painting. erection and qualit)' cO Jltrol.
The Section is organi zed <\.'0 follows: 513 .1 513 .2 5 13.3 5 13.4 513.5
Sl eet and Mc ta!
Shop and Erection Drawings Fa brica tion Shop Painting
Erection Quality Control
513.1 Shop and Erection Drawings Shop drawi ngs shal! be prepared in advance of fabrication and give complete information necessary for the fabrica tion of the component paris of the structu re. including the focation. type and size of welds and bo ils. Erecti on drawings shall be prepared in advance of erect ion and give
information necessa ry for erection of th e structure. Shop ;]nd erection drawings shall clearly di stin gui sh between shop and field weld s and bolts and shall clearly identify hi gh·strcngth bolted prctensioned and slip-critical connections. Shop and erection drawings shall be made with due regard to speed and economy in fabri cation and erection . 513.2 Fabricalion
513.2.1 Cambering, C urving and Straightening Local appl ication of heat or mechanical means is pennilted to be used to introd uce Of correct camber. curvature a.'1 d straightness. The tcmpcralUre of healed areas, as measured
513.2.3 Planing of Edges
Planing or finishing of sheared or thermall y cut edges of plates or shapes is not required unless specifically called fOf in the contract documents or included in a stipulated edge preparation for welding, 513.2.4 Welded Construction The ' technique of welding. th e workmanship, appearance and quality of welds, and the methods used in correcting nonconforming work shall be in accordance wi th AWS D1. 1 except as modified ill Secti on 510.2.
by approved methods, shall not exceed 1,100 ' F (593 'C) for A5 14/A514M and A852/A852M steel nor 1,200
·r
(649 'C) for other steels. 513.2.2 Thermal Cutting
Thermally cut edges shall meet the requirements of AWS Dl.l , Sections 5. 15. 1.2, 5. 15.4 .3 and 5. 15.4.4 wi th the exception that thermall y cut rree edges Ihal will be subject to calculated stat ic tensi le stress shall be rree of rou ndballom gouges greater than 5 mm deep and sharp V-shaped notches. Gouges deeper than 5 mm and notches shall be removed by grinding or repaired by we lding. Reentram corners, except reentrant corne rs of bea m copes and weld access holes, shall meet the requirements of A\\'S DLI , Section AS.J6 . Jf anothe r s pecified contour is required it must be show n on [he conlract documents. Beam copes and weld access holes shall meet the geometrical
513.2.5 Boiled Construction Parts of bolted members shall be pinned or bolted and rigidly held together during assembly. Use of a drift pin in bolt holes during assembly shall not distOl1 the metal or enlarge the holes. Poor matching of holes· shall be ca use for rejec ti on . Bolt ho les s hall comply wi th the provisions of the RCSC Speci fi cati on for Structural l oi nts Using ASTM A325 or A490 !lollS, Sect ion 3.3 except that thermall y cut holes shall be pCl'lnitled with a surface roughness profi le not exceeding 25 ,un as defined in AS ME !l46.1. Gouges shall not exceed a depth of 2 mm.
full y inscned finger shims, with a lOla] thi ckness of nol more than 6 111m within a joint, are permitted in joints wi thou t changing the strength (based upon hol e type) for the design of con nections. The orie nt at ion of such shims is
National Siru ciural Code of the Philippines 6'h Edition Volume 1
:;i-112
CHAPTLH:}
Steel (]nd Met<-lis
indepcndent of thc direction of application or the load, The use of high-strength bolts shall conform to the requirements of the RCSC Specification for Structural Joints Using ASTM A325 or A490 Bolts, except as modified in Section 510.3.513.2.6 Compression Joints Compression joints that depend on contact bearing as part of the splice strength shall have the bearing surfaces of individual fabricated pieces prepared by milling, sawing, or othcr suitable means.
513.2.7 Dimensional Tolerances Dimensional tolerances shall be III accordance with the AISC Code of Standard Practice for Steel Buildings and Bridges.
513.3 Shop Painting 513.3.1 General Requirements Shop painting and. surface preparation shall be in accordance with the provisions of the AISC Code of Standard Practice for Steel Buildings and Bridges. Shop paint is not required unless specified by the contract documents.
513.3.2 Inaccessible Surfaces 513.2.8 Finish of Column Bases Column bases and base plates shall be finished in accordance with the following requirements:
J.
2.
3.
Steel bearing plates 50 mm or less in thickness are permitted without milling, provided a satisfactory contact bearing is obtained. Stcel bearing plates over 50 111m but not over 100 BUD in thickness arc permitted to be straightened by pressing or, if presses arc not available, by milling for bearing surfaces (except as noted in subparagraphs 2 and 3 of this section), to obtain a satisfactory contact bearing. Steel bearing plates over 100 111m in thickness shall be milled for bearing surfaces (except as noted in subparagraphs 2 and 3 of this section).
Except for contact surfaces, surfaces inaccessible after shop assembly shall be cleaned and painted prior to assembly, if required by the design documents.
513.3.3 Contact Surfaces Paint is permitted in bearing-type cOllnections. For slipcritical cOllnections, the faying surface requirements shall be ill accordance with the RCSC Specification for Stnlclural Joints Using ASTM A325 or A490 Bolts. Section 3.2.2(b).
513.3.4 Finished Surfaces Machine-finished surfaces shall be protected again.sl corrosion by a rust inhibitive coating that can be removed prior to erection, or which has characteristics that make removal prior to erection unnecessary.
Bottom surfaces of bearing plates and colulllll bases that are grouted to ensure full bead ng contact 011 foundations need not be milled.
513.3.5 Surfaces Adjacent to Field Welds
Top surfaces of bearing plates need not be milled when complete-joint penetration groove welds arc provided between the column and the bearing plate.
Unless otherwise specified in the design documents, surfaces within 50 mm of any field weld location shall be free of materials that would prevent proper welding or produce objectionable fumes during welding.
513.2.9 Holes for Anchor Rods Holes for anchor rods shall be permitted to be thermally cut in accordance with the provisions of Section 513.2.2.
513.2.10 Drain Holes When water can collect inside HSS or box members, either during construction or during service, the member shall be sealed, provided with a drain hole at the base, or protected by other suitable means.
513.2.11 Requir'emcilts for Galvanized Members Members and parts to be galvanized shall be designed, detailed and fabricated to provide for flow and drainage of pickling fluids and zinc and to prevent pressure build-up in enclosed parts.
Association of Structural Engineers of the Pllilippines
CHAPTEH !>
Sleel anclMe tal
5·11 ::5
513.5 Quolit), Control 513.4 Erection 513.4.1 Alignmenl of Column Bases
Column hascs sh.tll he SC I level and 10 correct clcvmioll with full bearing 011 concrete or maso nry.
513.4.2 Bracing The frame o f steel ske le ton buil di ngs shall be cflrricu lip true and plumb within the limits defined in the A l SC Code of Standard Practice for Steel Bui ldings and Bridges. Temporary bracing shall be provided. in accordance with the requ irements of the Code of Sta ndard Practi ce for Sleel Buildings and Bridges, whe rever necessary to suppOrt the loads to whi ch [he struc ture may be subjected, in cluding equipment and the operati on of same. Such bracin g shall be left in place as long as required for safe ty,
T he fabricator s hall provide qualit y control procedures to the C.Xlent that the fabric.:ator deems neccssary (() assure thm thc work is performed in accordance with this Spccific
513.5.1 C ooperati on As far as possible, the in spection by re prese ntati ves of the pu rc haser sha ll bc mad e at the fab ri cator'S plant. The fabricator shall cooperate with th e inspector, permitting access for in spection to all places wh e re work is being don e. The purchaser's inspector sha ll schedule th is work for mini mum int erru pt ion to the work of the fabri cator.
513.4.3 Alignment No pe rmanent bolt ing or welding sha ll be pcrfonncd un til Ihe adjacent affected portions of Ihe structure h;we been properl y al igned.
513.4.4 Fit of Column Compression Base 1>lates
Joints and
Lack o f contac t beari ng not exceedi ng a gap of 2 mm , regardless of the type of splice used ( paJ1 ial -joint· penetrat ion groove welded or bo lted). is permitted. If the gap exceeds 2 mm, but is Icss than 6 mm, and if a n e ngineeri ng in vestigati on shows that suffic ie nt cont act area does not exist , the ga p sh all be packed out with nonlapered steel shims. Shims need not be oth er than mild steel, regardl ess of the grade of the ma in materi al.
513.5.2 R ej ections Mmerial or workmans hip not in conform ancc wi[h the provisions of this Specificatio n may be rejected at any ti me du ring the progres s of th e work. Th e fabricat or shall recei ve co pies of all reports furnished to the purc haser by th e inspecti on agency.
513.5.3 Inspect ion of We ldi ng The inspection of welding shall be performed in accordance wit h the provisions of AWS 0 1.1 except as modifi ed in Secti on 5 10.2. Whcn visu al in specti on is required to be perform ed by A WS certifi ed weldin g inspec tors, it shall be so specified in the des ign documents. When nondestructive testing is req uired , the process, ex tent and stand ard s o f acceptance shall be cl earl y defin ed in thc design documents.
513.4.5 Field Welding Shop pai nt on surfaces adjacent to joints to be field welded shall be wire brushed if necessary to assure weld qualit y. Field welding o f attachments to install ed e mbe dme nts in contact with concre te shall be done in suc h a mann er as to avoid excessive thennal expansion of the e mbedment which could result in spallin g or c rac king of the co ncrete or c xcess i ve stress in the c mbedmelll anc ho rs.
513.5.4 Ins pection
of
Slip-Critical
High-Strength
Bolted Connections. T he in specti on of slip-criti cal hi gh-strength bolted co nnection s shall be in accordan cc with the provisions of the RCSC Specification for Structural Joints Using ASTM A325 or A4 90 Bolts.
513.5.5 Id entifi cation of Steel 513.4.6 Field Painting Responsibility fo r touch-up painting, clea ning and field pa inti ng sh all be allocated in accorda nce with acceptcd local practices, and tb is allocat ion shall be scI forth exp lic itl y ill the des ig n docum ents.
The fabricator !ihall he able to dcmonstrate by a wrillcn procedure and by actual practi ce a mc thod of material ide ntific ation, visible at leas t through th e "fi t-up" operatj on, for the main sl rtlctural clements of each ·· "1
513.4.7 Field Connections As c rec[i on progresses, the structu re shall be secure ly bo lted or welded to support the dead, wind and erection loads.
Na tio na l St ructura l Code of the Philippines 61b Edition VolLlme 1
!)
11 t!
CHAPTl~n:)
Stet?i and Metal::;
APPENDIX A·l INELASTIC ANALYSIS AND DESIGN Design by inelastic analysis is sub.iect to the supplementary provisions of this appendix. The appendix is organized as follows: A-I.I
A-l.2 A-1.3 A-I.4 A-1.5
A-1.6 A-t.?
A- J.8 A-I.9
General Provisions Materials Moment Redistribution Local Buckling Stability and Second-Order Effects A-I.Sa Braced Frames A-I.8b Moment Frames Columns and Other Compression Members Beams and Other Flexural Members Members under Combined Forces Connections
where
Ag Fy
::: gross arca
or mcmber, mm?
:=specified minimuill yield stress of the compression flange, MPa ::: resistance faclOr for compression::: 0.90 :::safety factor for compression::: 1.67
nc
A-I.4 Local Buckling Flanges and webs of members subject to plastic hinging in combined flexure and axial compression shall be comp:H.:\. with width-thickness ratios less than or equal to the limil;I);! Ap defined in TabJe 502.4.1 or as modified as follows: ~, For webs of doubJy symmetric wide flange members and rectangular fiSc)' in combined flexure and compression
I.
--j E
2.7S1~,
1'.1'
ehl y
hl[", <;3.76 -_-(1---,-)
A-I.1 General Provisions Inelastic analysis is permitted for design according to the provisions of Section 502.3.3 (LRFD). Inelastic analysis is not permitted for design according to the provisions of Section 502.3.4 (ASD) except as provided in Section A-I.3. A-1.2 Materials Members undergoing plastic hinging shall have a specified minimum yield stress not exceeding 450 MPa.
A-1.3 Moment Redistribution Beams and girders composed of compact sections as defined in Section 502.4 and satisfying the unbraced length requirements of Section A-I.?, including composite members. may be proportioned for nine-tenths of the negative moments at points of support, produced by the gravity loading computed by an elastic analysis, provided that the maximum positive moment is increased by onetenth of the average negative moments. This reduction is not permitted for moments produced by loading on cantilevers and for design according to Sections A-IA through A-I.S of this appendix.
If the negative moment is resisted by a column rigidly framed to the beam or girder, the one-tenth reduction may be used in propor1ioning the column for combined axial force and flexure, provided that the axial force does not exceed O.15f,Fy A, for LRFD or O.15f,·A,IQ, for ASD,
(A-l-l )
where = modulus of elasticity of steel = 200,000 MPa :;:: specified minimum yield stress of the type uf steel being used, MPa :;:: as defined ill Section 502.4.2, mm :::: required axial strength in compression, N :::: member yield strength, N ::: web thickness, mm :;:: resistance factor for flexure;::: 0.90
E
r:r h PI!
1\ I",
$" 2.
For flanges of rectangular box and hollow stnl' sections of uniform thickness subject to bendi; compression, flange cover plates, and diaphraglll between lines of fasteners or welds
bit
S;
O.94JE/F).
where b
3.
::: as defined in Section 502.4.2, lllm :::as defined in Section 502.4.2, mm
For circular hollow sections in flexure
DI[ ,; O.04SEIF,·
Association of Structural Engineers of the Philippines
!llr~;l
!.... l ! }\P1EH:,
~) l i ~j
.sW(!i:1 rlU M CIil I
whcn.'
A-1. 7 Bea ms a nd Othe r Fl ex ur:tl M emb ers
I)
T he required mO lHent slrcngth. M il, of hea lll s dc!
;:: outsitlc diameter of fOund HSS mcmber. nUll
Ihe h;I!
A· I.S S iubilif y and Second -Order Efl'crls
slrcnglh. $M". wher.,;
Continuous beams nOl subjected to
be des igned based on (I first -order inelastic analysis or it plaslic Il1cchani!; 111 antilysi s. Braced frames and moment fnllllcs may be designed bi.lsed 011 a firs t-order ine l:.\ stk una lysi s or ;t pl
'.
Structures may be designed on the basis of a second-ord er inelastic ana lys is. For beam-columns, connections and connected members, the required strengths shall he determined from a second-order inelas tic analysi s , where equi li brium is satisfied on the deformed geometry, taking into accounllhe c hange in stiffness due to yie ldi ng.
(A - I-Il)
$ = 0.90 (LRFD ) Design by inelastic analysis i!
I.
A-l.Sa Braced Frames
For doubly symmelric and singly symmc tric I-s haped membe rs wi th the compression nange equal to or la rger than the len!
M
£
In brac ed fmflles designed 011 the bas is of inelastic analysis. braces shall be des ig ned to remain clastic under lhe design loads. T he required axial strength for col umns and com press ion braces sha ll not exceed tj;.. (0. 85 I-~)"A,).
where
w he re
M!
= smaller moment at e nd of un braced length of
M2
= la rger moment at end o f unbrnccd length of
1) ·
= radius of gyralion about mi nor axi s. mm(MIIM2)
<1>..
=0.90
L"" = IO.1 2+ 0.076(-M' )](F)r, 2
(A-I-7)
,
beam, N-ffilll
LRFD)
beam, N-mm
A·l.Sb M oment Fra mes In mo ment frames designed on the basis of inelast ic analysis , the required axial strength of columns shall not exceed ~(0.75F)"A,).
is positive when moment s calise reverse curv
For so lid rectangular bars and symmetric box beams:
where
M E E L pd =[0.17+0.10(-' )I( - ) r,. ~ O. L O(-)"r M, F,. . F,.
¢c = 0.90 (L1~FD)
(A-I-8)
A-1.6 Columns and Other Compression Members In addi ti on to th e li mits set in Sections A- I .5.a and A-1.5 .b. the req uired axi al stre ngth of col umns designed on the basls of inelastic a nal ysis shall not exceed the design strength, cf>cPn, detemuncd according to the provi sions of Section 505.3. Design by inelastic am'lysis is pennitted if the colullln slenderness rali o, U r, does not exceed 4.71J £/ Fy • where
L r
= lalerall y ullbracc-d length of a member, mm
= govern ing md ius of gyra tio n. m m
111erc is no li mit on Lb for members with circular or square c ross sections or for any beam ben I about its minor axis.
A- 1.8 M e muer s under Co m bin ed F or ces When ine lastic analysis is used for symmetric members subj ec t to bending and axial fo rce. Ihe provisions in Section 508. ) appl y. Inelastic analysi s is lI ot permitted for members subject 10 torsion and combined torsion, flexure. she..1r an(Vor axial force. A-1. 9 Connecti ons Co nnections adjace nt to plnsti c hing in g regions of co nnected members shall be designed wi th suffi cient strength and ductili ty 10 sustai n the forces and deformations im posed under the req uired loads.
National SLructural Code of tile Philippines 6'" Edilion Volu me 1
5-11 G
CHAPT EH 5 - Steel and Metals
=r:::r :: _:
34 ~ 3 2 - - -· ·
=_ -.
3.0 - ---- - 2.8
This appendix provide!; methods for delCnn ining whether a roof system has adequate strength and stiffness 10 resi st pondin g.
_._-
2.6·
---
-- - - - .- - ...
2.4
-- .-.. -.... --- ._, ..- .- .
2.2 -
~ 2.0 -~=--j~~-:-t---i::····~-'%:j:: - ··-1£- -:: ~ : ~ == 1.8 - _ _ _ . _ - -+ _- .-t -
The appendix is organized as follows: A-2.1 A-2.2
:ll
Simplified Des ign for Ponding Improved Design for Ponding
e~ 16 .
A-2.t Simplified Design for Ponding
1.2
The roof sys tem shall be considered stable for pond in g and no funher in vestigati on is needed if both of the following two conditions are mel:
1_0
Ct' + O. 9C, :" 0.25
I" ~ 3940 SA where
504L,L" C=-_·_-., 1
4'
-
0.6
0.7
0 .8 0.6
(A-2- 1)
0.4
(A- 2-2)
0.2
oiJI
0.1
,
0.3
0.2
0.4
0.5
Upper Limit of Flexi/)ilily Cons/ani Cp
Fig.
d
C,
_ . -
5045L,'
A-2·1. Limiting flex ibiliry coefficienr for systems.
rh e primaJ)'
f-or secondary members, the stress ind ex shall he
l,
V =(
= column spaci ng in direclioll of girder (length of
,
0.8F,. -
10
10
)
(A-2-4)
primary members), m
Ls
= co lumn spacing perpendicular \0 direction of
S Ip Is Id
girder (length of secondary members), m == spacing of secondary members , III 4 moment of inenia of plimary members. mm = moment of inertia of secondary me mbe rs, Illm4 == mome nt of inenia of the sleel deck supp0l1ed on 4 seco nda ry members, mm per III
=
For trusses and steel joists, the moment of inertia Is shall be decreased 15 percen t when used in th e above equation. A steel deck shall be considered a secondary member when it is directly supported by the primary members.
A-2.2 Lmprovcd Design for J)onding The provision s given below are permilted LO be lIsed \",hen a more exac t de termination of framing stiffness is nceded than that given in Section A-2 . 1.
where
In D
R
= stress due \0 the load combination (D + R) = nominal dead load = nominal load due to rainwater 01' snuw, exclusive of the pondin g cOlU ribution, MPa
For roof framin g consisting of primary and secondary members, the combined stiffness shall be evaluated as follows: enter Figure A·2· 1 at the level of the computed stress indcx Up determined for the prim ary beam; move horizontally to the compu ted Cvalu c of the secondary bcnnu; and the n downward to the abscissa scale. The combined stiffn ess of the primary a nd secondary framing is . suffic ient to prevent ponding jf the n ex ibi lity constanL read from this laller scale is more than the va lue of Cp computed fo r the given primary me mber; if not, a sliffer plimary or secondary beam, or combination of bOlh, is required .
For primary members, the stress index shall be
V,,=(
0.8F, -
10
10
)
(A-2-3)
Associa tion of Structural Engineers of tile fj hilippines
CHAPTE n ~J
Sl
~) .
I 17
A similelr p n x:cd ur~ must bc followed using Figll re A-2-2. 3 ~
-- - -
I - r~!
32 ~
=~~ :J -
= - --_~.
r=~Y. - ':1
3.0
2.
2-1§li~I?1~Iiittll '1_. .._
2.2
1-""-'-' !} 2.0 - -
j
A·3 .1 A· 3.2
' .8 _. - 1.-/
A·3.3 A· 3,4 A·3.5
1.2 1.0
0 .•
O. 04 --
0.2 00
The lolppendix is organized as roll ows:
"
... 1.6
,~ ¥,
This appcndix applies 10 members and COllllcctiollS sllbjecI to high cycle loading within the clasti c range of stresses of frequcncy ,md magnitude sunil' jelll (0 initiate cracking and progressive. failure, whi ch defines the limit slate o f fatigue .
0. 1
02
0.3
0.-1
0 .5
06
0 .7
General Calculation of Maximum Stresses and Stress Ranges Design Stress Range Bolts and Threaded P ailS Special Fabrication and Erecti on Requirements
A·3,\ General The provisions of this Appendix apply to stresses calculated on the basis of service loads. Thc maximum permitted slress due 10 unfaclOre:d loads is O.66Fy.
Upper Limit of FlexilJilty Consr8ri Cs
Fig. A -2-2. Lilllilitlg fleXibility (:oc/ficieru for rile secolldtll), s),stems.
For roof framing consisting of a series of equally spaced wall-bearing beams, the stiffness shall be evaluated as fo llows. The beams are considered as secondary members sup ported on an infinitely sliff primary member. For (his l:lISC, enler Figure A-2-2 with the computed STress index UJ . The limiting value of Cs is determined by the intcrce pl of a horizontal line reprcsenting the U~ value and the curve for
el ,:::. O. Uscr N9(el Ti1e poodingof prul~f\liat it IS suffiiiienlm:erely:.to'\UiUt its mOIl!~nt, of)l!~riia ~r:)n~te~ 9.f!l'.id./!1 ri9~aJ to :it~ ,..p,~ 10
3940,mm/m.
',.: " .,'
...
:c~' ...
In the case of complete-joint-penetration but( welds. the maximum de sign stre."iS range calculated by Equat ion A-3-) applies only to welds wiLh intemal soundness meeting the acceptance requirements of Section 6.12.2 or 6. 13.2 of AWSDLL No evaluation of fatigue resistance is required if the live load stress range is less than the thresho ld stress range, Fill. See Table A·3· L
;-" ." ' : , ..,:,; , . .
For roof fram ing consisting of melal deck spanning between beams supported on columns, the stiffness shall be evaluated as follows. Employ Figure A-2- 1 or A-2-2 using as CJ the flexibility constant for a I III width of the rooC deck (S
Stress range is defined as the magnitude of th e change in stress due to the application or removal of the service live load. In the case of a stress reversal, the slrc.."is range shall be co mputed as the nu merical sum of maximum repeated tensile and compressive stresses or the numerical sum of maximum shearing stresses of opposite direction at the poi nt of probable crack initiati on.
= 1.0) .
National Structural
No evaluation of fatigue resistance is required if the number of cycles of application of live load is legs than 20,000. The cyclic load rc sistnnce detcrmined by th e provisions of this Appendix is appl icable to structures with su ilable corrosion prolection or subject only to mildl y corrosive atmospheres, slIch as normal atmosphelic conditions. .. ·nle cyclic load resistance determined by the pro visions of thi$ Appendix is applicable onl y to structures subject to tem peratures not exceeding 300°F (ISO°C).
Code of the Philippines 6'"
Edition Volume 1
F
The engincer-or-record shall provide ei ther compl lelc deUl ils incl uding weld sizes or shall specify the planned cycle lire :11111 Ihe 1ll:l.\:i IlHlIlI rtlllgc of lllomenJ:... shears and n:ilt.: lions for the c.:o nncl'tions.
Calcu lated st resses shall be b<:lsed upon clastic alwl ysis. St rcsses shall not he amplified by st ress concel1t nuion filClors for geometrical discoJllinuitics. a.
For axially loaded angle members where th e center of grav ity of th e cOllnecting welds lies between the !tne of th e ce nt er of gravi ty of the angle cross section and the ce nter of the con nected leg, the effects of eccentri cit y shall be ignored. If the center of gravi ty of the connecting we lds lies out side this lone, the total stresses. incJuding those due to joint cc.:cclltricit y. shall be included in the calculation of stress range .
N
b.
C,
F,"
~
F
TH
IIf
(5 I )
(A -3-3)
_."
Based upon crack ini ti ltti on from the root of the weld the design stress nlllgc, F SH, 011 the lell5io[1 loaded plme clement usin g transverse PJP groo ve we lds, with OJ· without reinforcing or con touri ng fillet welds, I !"· design stress ran ge on th e cross secti on al the toe of !!:: weld shall be determin ed by Equation A-3-4, stress category C_ as follows:
14.4XIO"
N)
0.333
(A -3-4)
(5 .1.)
where Rp)p
reinforced or groove welds
the reduc ti on factor for nonrcinforced transverse P1P dctennin ed as follows:
is
0333
~
10 (5.\.)
(A-3- 1)
If RPJP = 1.0, usc stress category C.
2a = design stress range, MPa = constant from Table A-3-1 for the categ()ry = number of stress range flu ctuati ons in de-.s ign life = number of stress range fluctu atio ns pe r day x 365 x years of design life = threshold fatigue stress range, maxi mum stress range for indefinite design life from Table A-3 ~
I , Mr" 2.
N
Fm = 111'11' (
where
N
-
For Slress calegories A, B, B_, C, D, E and E_lhe design stress range, FSR , shall be determined by Equalion A-3 -1.
FSR -- (e[ X 329 )0.333
P.\-H
>F
_ ( 14.4XIO")0JJ3>689
1\-3.3 Design Stress Range The range of stress at service loads shall not exceed the design stress range computed as rollows. I.
)". 11,'
Based upon crack initiation from the loe of the weld On the tension loaded plate clement the design stress rang... . F SR. shall be dcteOlli lled by Equation A -J-3, for strcs:-. category C which is equ31to F,,-
foOl' members having symmetric cross sections, the fasteners and welds shaH be arranged sy mmetrically about the axi s of the member, or the total stresses including those due to ecce ntricity shall be included in the calcu lation of the stress I':l nge .
N
For tension-loaded pl atc dements t.:olllll"t.:lcd ilt Ihcii end by cruciform. T. or corner dcta ils wi th complelcjoilll~pcneiratioll (CJP) groo"e welds ()f partial joillt penetration (PJP ) groove welds. fillet we lds, or co mbination s of the preceding. tntllsvcrse-. to I/!,: direction of stress, the design stress range 011 Ihe ("rl)'-.·' section of the tension-loaded plate clement ill the toe l. J ( the weld shall be detcnnined as follows:
A-3.2 C'llcul;slion of Ma xi mulIl Stn'sscs and Str"css n a Jl gcs
For bolts and threaded rods subject 10 axial tension. the calculnted stresses shall include the effects of pryill1g aClion. if any. In the case of ax ial stress co mbined with bending. the maximum stresses. of each kind , shaH be those determined for concurrent arrange ments of the 3pplie(J load .
_(c:rI IX IO'
.'iN -
For stress category F, the design stress range, Psn, shall be determined by Equation A-3-2.
= the length of the Jlollweldcd
roOl
direction of the thi ck.ness of Ihe plate. 111m w
tl'
c.
face in
( :. >
Icnsion- l o~H.h..c
=the leg sile of the reinforcing or contonrin" fillet, if any. in the direction of the t hi cklll::,~> ,.: the tension-loaded plate. 111111
= thickness of tension loaded plate,
II1Ill
Based lIpon crack initialion from the root s of :1 :', . transverse fillet we lds on opposite sides of til(: t ,:.; .. loaded plate element th e des ign stress range, h·/i, Oil tli,;
Association of S tru ctural Enginee rs of tile Philippines
c ros ~
section
by Equation A-1- 5, strcss Ciltcgory C as follows ;
,..
.'"
_/I
-
m.
( 14.4XIOII
N- - )
U.3.1I
(S. I. J
(A -3-5l
where Hm. is the reduction facI o)' for joints llsing a pair of transverse fillet welds only.
I,)) S 1.0
0.10;. 1.24("'/ 1
RFIJ. [
0. 167 1I'
Jf R"'IJ. = I .0, usc stress category C.
The nlngc of st ress .11 sen'ice IO<1ds shall not exceed th e stress runge computed as follow s.
2.
A-3.S Specia l Fabrication
~lIld
For mechanicall y fastened connections loaded in shear. the m:lximum r:mgc of siress in the cOllllccted material at service loads slwlt not exceed Ihe design stress rilngc co mputed using Equ:uion A-3-1 where C, and F rot arc wken from Sectioll 2 of Table A-J. I.
For high- strength bolts, comm on bolts, and threaded anchor rods with CUI , ground or rolled threads, the maximum range of tensile stress on the net tensile area from applied axial load (lnd moment plus load due (0 prying action shall not exceed the design stress range computed using Equation A+3-1.
The fac tor Cf shall be taken as 3.9 x 108 (as for stre ss category E'). The thresho ld stress. Fnl shall be laken as 48 MPa (as for stress cmego r), D). The net tensile arc'l is given by Equation A~3·6 . (S. I. )
(A -3-6)
where
Lon gitudin<:l l backing bars afC permittcd to remain in place , and if used, shill: be' continuous. If splicin g is necessary for long joi nts. the har shall bc joined wit h complete pCllctnllion bUll joints and the reinforcement ground prior 10 assem bly in the joint.
P Db
= pitch, mm per thread = the nominal diameter (body or shank diameter).
'1
= threads per 111m
In tran sverse complete-jojnt ~ pe llelrati on T and corner jOints, a reinforcing lille! weld, not Icss than 6 mm in size shall be added •.11 rC -cll tralll co rners. The surfacc roughncss of ~lIn.
I !
cut edges subject
to
where AS ME B46.1 is the refercnc:c standard.
Reentrant corne rs at cut s. copes and we ld access holes shall fonn a radius of not less than 10 I11Ill by prcdrilling or su bpunching and reamin g a hole, or by thermal cutting to form the radiu s of th e cuI. Jf the radiu s portion is for med by therm al cutting, the cut surface shall be ground to a bright metal surface. For transverse bUH joints in reg ions of hi gh tensile stress, run -off tabs shall be used to pro vide for cascading the weld termination olltside the finished joint. End dams shall not be used. Run~off tabs shall be removed and the end of the weld fini shed nush with the edge of the member. See Section S I0.2.2b f Of requirements for end retu rns on ceI1ain fillet welds subject to cyclic service loading.
For join ts in which the mat erial within th e grip is not limited 10 steel or jOints whi ch are no! ten sioned 10 the requirements of Table 5 10.3. 1, all ax ial load and moment applied to the joint plus effects of any prying action shall be assumed to be c arried exclusivcly by th e bolts Or rods.
I
nil/He
signifi cant cyc lic tensi le stress ranges shall nOI exceed 25
mm
i
Erection Requiremcnts
In tra nsversc joints subject to tension. backing hal'S, if used. shall be removed and thcjoillt back gouged and welded.
A-3.4 Bolls and Threaded Parts
I.
the tensile stress nlllgc in the prctcnsiollcd holts due to the total service Ii ve load and moment plus effects of any pryin g acti on. Alternatively. Ihe stress ran ge in the bolts shall be ass umed to he equal to the stress on the net tensile arca due to 20 pen:':l!1lt of the absolute vn lue or the service load ax iilllo
For joints in which the material within the grip is limited 10 steel and which are tensioned to the requ irement s of Table 510.3. 1. an analysis of th e relati ve stiffness of the connectcd parts and bolts shall be permi(led 10 be used 10 determine
National Structural Code of the Philippines 6'" Edition Vot ume 1
APPENDIX A-4 ~T,RtJ<;;n.!~LDESIGN FOR F~RE
CONDITIONS Thi s 1Jppcndi x provides criteria fOl' th e design and evaluation of' struc tural stee! com pollcllIs, sys tems and frames for fire condi tions. These cri teria provide for the determination of the heat input, thennal expansion and dcgradatinn ill mechanic .. ] propcItics of materials at clcv.ltcd iCilIpcraturcs that cause progressive decrease ill strength and stiffness of structural components and systems at eJcvoHcd temperatures. The appendix is organized as follows :
A-4 .1 A-4 .2 A-4 .3
Gcncml Provisions StruclUml Design [or Fire Conditions by Analysis Des ign by Qualificalion Testing
A-4.1 Gcncntl Provisions The mClhOLl s co ntained in this appendi x provide regulatory evidence of compl iance in accordance with the: design applicati()n~ outlined in this section.
The appendix uses the following terllls in addition 10 the terms in the G lossary.
ACTIVE FIRE PROTECTION: Building m.lerials and systems that a.re activated by a. fire to mitigate adverse cffects or (0 notify people 10 take some action Illiligare adverse effects. COMPARTMENTATION : The enclosure of a buildin g space with clcmcllIs Ihal have a specific fire endurance. CON VECTIVE HEAT TRANSFER: The Iransfer of th ermal energy from a point of higher temperature to a point of lower temperature. through the motion of an int ervening medium. DESIGN-IlASIS FinE: Asel of condilions Ihal define Ihe
development of a fire and the spread of combustion products throu ghout
11
building or portion thereof.
ELEVATEIJ TEMPERATURES: J-iealing condilions experienced by building elements or structures as a resull of fire. which (lrc in excess of the amicip'IICd <11llbient conditions.
FIRE: Destructive burning, as manifested by any or all of th e fQllowing: light , flame, heal, or smoke.
Association of Structural Enginee rs of the Philippines
·..
------------
-----------.-~.,-.-----.------~-.
- - --- -J-----
-r---------- -r---- ------- -
Table A-3.t Fatigue Design Parameters
---
, SIJCSS Cltegol)
Des(11 )!IOl) I
--T-~-~
(onstant
Till eshold
, Potent),,1 (r,lCk InltJdtlllll PUlill
r
Cj III III'" - - - -- -- - -- --- -- ------ ---------------- -------- - - ---- - ----- ---- ----- --------- ---SECTION I -PLAIN MATEItIAL A WA Y FROM ANY WELDING -----_._. __ .--_._---. .. _---_.-------- . . --_ ... ,--...
-,---.
"-·I-.··I-·B,l.~c~~~~.;: exc~~;;~' -;I-;:;~:oal~I-T---'-
wealllcrilig sled, with rolled or cleaned surf'ace. Flwl1e-cut edges with surface roughncss value of 25 pm or less but witllOU! recntrant corncrs, ---.~,,~--.---.-,-~
---.~-~.~-----.
2511 x lOs
A
--
....
1.2 NOll-coaled welilhering sleel base metal with rolled or cleaned surface. Flame-cut edges wilh surface roughness value of 2S pm or less, but without reentrant corners . .------.. 13 MClllbef wilh drilled or reamed holes. Member with reentrant corners at copes, Cllls, b!ock~Ollts or other geometrical discontinuities made to requiremellts of Appendix 3.5, _~~~.'::.~J2.~~:£~(L!.~.~~~5s hoi e s. 1.4 Rolled cross sections with weld access holes made to requirements of Section 510.1.6 and Appendix A-3.S. Members with drilled or reamed holes corllaining bolts for attachment of light bracing where there is a small longitudinal component of brace force.
~----.----
Away from all welds ur structur,ll connections
165
------------- - - - - - -
120 x lOX
II
__
Away from aJJ welds Of structural connections
1111
-_•. _._ .. _----
--
~-,
120 x 10'
13
A! any external edge or ,H hole peri meter
110
-
..
44 x 10'
C
At reentrant corner of weld access hole or at any small hole (may contain bolt for minor connections)
69
- - - - - - ---------- ----------SECTION 2 - CONNECTED MATERIAL IN MECHANICALLY FASTENED JOINTS
2.1 Gross area of base metal in lap joints connected by high-strength bolts in joints satisfying all slip-critical requirements for connections.
B
2.2 Base metal at net section of high-strength bolted joints, designed on the basis of bearing resistance, btlt fabricated and installed to all requirements for slip-critical cOllllections. .. _---_._._----_._---_.
B
__
120 x 10'
110
Through gross section near hole
110
In net section originating at side of hole
.._-
---~-.~.,,-
."....
120 x lOx
--~.-
..---
_._--
....
~
~.---------.-.~.--
...... _-----,.
2.3 Base metal al the net section of other IllCc!1I1l11cally fastened joints except eye bars and pin plates
-...
--~-
D
..---
2.4 Base meta! at net section of eyebar head or pin plate.
22 x 10H
48
----- - - - - - - - _..- -------- .- E
II x 10"
31
In net section originating at side of hole -~-.-~.--
In net section originating at side of hole
-
--'--
Nationa! Structural Code of the Philippines 6
th
Edition Volume 1
_
_--,,-=::!~Ta:::b::.le'..:A:::'!!!:3::c.l~( z::n~t.)=:.:.....--------~---------~~------l Fafigue.Desigll.Pal'!.m!¢ters_~ .... _ .... _ CO'::_
IlluSlrative Typical Examples
f. J and 1.2
- - - - - - - _ . _ - - - - ----_.
__.__ __._._----_.__ ._--_._--_._-._-_. _._-_.._ - - - - - - ..
1.4
..
-----.--.-~~~
SECTION 2 - CONNECTED MA TERIAL IN M~~II_i\,l'I!~:\!:LYl'~l'.!'NED JOIN.,-,T"S,---~_____._______... 2.1
Ie!
@
2.2
2.3
---------2.4
.----~-----------------------
Association of Structural Engineers of Ole Philippines
CHAPTEf·1 5
Stress Category
Descriptioll
Steel and Metal
C)·123
Potential Crack Initiation Point
Constant
Cj ,;
Jl
3.2 Base metal and weld metal in members without attachments buillup of plates or shapes, connected by continuous longitudinal complelejoint-penetration groove welds with backing bars not removed, or by contin UOU$ pal1 ial-joi Ilt-penetration
termination of longitudinal welds at weld access holes in connected
120 x 10~
110
From surface or internal d;scontinuitics in weld away from end of weld
ll'
61 x 10
8
83
From surface or internal discontinuities in weld, including weld attaching backing bars
D
22 x 10 6
48
From the weld termination into the web or Oange
E
II x lOs
31
In connected material al start and stop locatiolls of any weld deposit
E
8
11 x 10
31
In flange at toe of end weld or in flange at termination of longitudinal weld or in edge of flange with wide coverplates
E'
3.9 x 10 8
3.4 Base metal at ends of
longitudinal intermittent fillet weld segmellts.
3.5 Base metal at ends of partial length welded coverplales narrower tban the flange having square or tapered ends, with or without welds across the ends of coverplatcs wider than the flange with welds across the ends. Flange thickness:5 20 mill Flange thickness> 20 mill
18
18
In edge of fiange at end of coverplate weld
loaded members with longitudinally welded end connections. Welds shall be on each side of the axis of the member to balance weld stresses. t
:5 20 mm
t>
Illm
E
31
11 x 1o~
18
E'
th
National Structural Code of the Philippines 6 Edition Volume 1
Initiating fro111 end of allY weld termination extending into the base metal
5- 124
CHAPH,H 5 - Steel
l i~;;( . ' \(,
,
i:':<:-:.'
",
....
-
Table A'3.1(cont.) ' FMigUe J).e$igl) J!ilfaml.ltllrs
.'
"'.
" '-
Illustrativt' Typil'a l E.'(itmpic-s
·,~eTlON 3-WELDEUJOINTSJOjNING 3.1
COMPONENTS OF BUILT-UP MEMBERS
{- f:: ---, ~a,:1' -::::....~~
. ~:.:(....
Rj (
-~ (hl--~~.J
<- -
- / ...
.. _--------_. 3.2 /.-
((I~ ~~,
~
:::,..;;:-.-
..
_._---------
'-
....
''I C~~t7iJ}-~---4t ::.~":.
(oj
---
3.3
C-;---.
(a)
]:1 ~~:" j
( I)) ~
~.
•. )I
~~
--.~ -. -.--- - --- -- .--
..
~
..- - -.
--
..
3.4
(a)S~4 (b)~ ~. ~
(C~
3.5
(~;.-~ ~JL)
(.)
--:-:t'••
(b)
(el
~ ---"-'
--_._-_._----_._.__
..-
-.
..-
3.6 (a)
~~N'~'
~
1~1h>.
----c;
SECTION 4 - LONGITUDINAL FILLET WELIDED END CONNEC'fIONS
-----"-
4.1 ___ ~ ___
"'~1(~~"'7
(al~~~ ~~ :,-: . . . .
- .....
U-.:"""'t"~1k
(b)
"'"~I , u":I.:' '''''7·
/'
.,,~.... ""'---. .....-
--
Association of Structural Engineers of the Philippines
Descri pti on
adjacent It) cOlnplclc-joinlpcnclnlliol1 groClvc wclded spl ices with wclds ground essen tially parallel j() the direction of stress :11 transitions in thic kness or width made 011 a slore no great er than 8 to 20%. F:.- < 620 M P.t
Slfl"SS
Potential Crack
C,uegory
Initiation Poinl
x.
10~
S
120
B
120x 10"
S·
6 1 x I O~
110
Il iJ
83
From interna l di~colll i lluilies in lill cr metal or along the ru ~ ioll boundary
From internal discontin uities in ril](:r metal Of along fusion boundary o r .11 start of transi ti o n wht!! F, ~ 620 MPa
5.3 Basc mctal with Fy equal to or greater than 6 20 MPa and weld mctal ill o r adjacent to co mplclcjoint -penc tration groove welded splices with welds ground essentially parall el to the direction of stress at Iran sitio ns in width made on a radius of nO! Jess than 600mm with the point of tangency
B
C
120x10' 'Si
110
44 x 10 6
69
From internal discontinuitics in filler metal v discontinuities a long the fusion boundary
from surface di scontinuity loe of weld eXI~. lldi!l~ into base metal or along fu :-;ion boundary.
;11
al
transverse end connecti ons of te nsion -load ed plate clements using par1ial-joini- pe netrat ion bUll o r T or comer joints. wilh reinforcing or contouring fill ets, FSR shall be the sma ller of the toe c rack o r ront c rack stress ran ge. Crack initiating from weld 10C : Crack initialing frolll Weld roOI:
In iti ating from geometrical discontinuity at toe of weld extending into base metal or, initialing :11 weld ront subject C
C'
4-1
~:
10"
(i9
to ten sion cxtendi ng up and then ()til through weld
Nunc provided
Eqn . A-) ·4
National St ructura l Code of the Philippines 6
1h
Edition Volume 1
5 126
CHAP l ER 5 · Sler:! and Met als
Jilustrllli vc Typical
f~xa ll!pJcs
5. 1
t:f1 (b )
5.2
5.3 l~i.
r· .-L{ (b)
5.4
5.5
•
Association of Structu ra l Engineers of the Philippines
.
'. ,,!i •. ':
Tabl~ A-~.l (cont.) Faiis!~e·'j)·eSt2ij'ir.iriilrieters
-
Description
Siress
COllstant
Category
Ci
Threshold Pm
Polcntial Crack Init iation Point
M I'a
SECTION 5 'iWELPED-.f OINTSTRANSVERSE:rO DIRECTION OF StRESS (cont'd 5.6 Base melal and filler metal al transverse end COIl IH!c tions of Icns]oll- io:ldcd plate clements using pl,ir of fillet welds on opposite sid es of the plate r~H !:ih'lll be the smaller of the toe crack or rool
"
crack stress range. Crack in itiating frolll weld toe:
C
Crack initialing from
C..
weld root:
44 x lOt(
69
&tn.
Nonc provided
Inililll ing from geometrical discontinuity al loe of weld ex tendi ng inla base
A- 3-5
melal or,
initialing at weld rool subject to ten sion extend ing up and then ou t through we ld
5.7 Base metal of tension loaded plale clemcnls and on g irders and rolled beam webs or flan gcs
C
44 X
108
69
From gCOI llctrieal d iscontinuit y at lac of fill et ex tending into base meW I
SE<;110N 6 - BASE METAL A'f WELDED TRANSVERSE MEMBE~ CONNECTIONS 6, I Base metal at detail s au ached by complete-j oint penetratio n groove weld s long itudinal subject 10 IO
B R?: 600mm
C 600mm> R?: 150mnl ISOcllm > R ~ SOmlll
0 E
120 x 10'
11 0
44 ;tIOS
69
22 x I O~
48
I I x IO!;
31
50lllm > R
National Structural Code of the Philippines 6'" Edi tion Volum e 1
Ncar point of tangency o f radius at edge of member
!i l?H
CHAPTEIl 5 STeel
.
~.
Jllu slr
5.6
fj'
r.~: :I! ··r
.I
(oj
L
J-i~·r·! f - · ···r·· (c)
-J-
··f ,.-<
,~, . ~~ ..
Association of Structural Engineers of the Philippines
Initiation Po int
thi ckness altachC{j joint-penetration groove su bject to trall sverse load ing wit h or without longitud in al loading when the detai l embodies a transi ti on mdi us R with the weld lenninalion ground s moolh: When weld reinforcement is not removed :
R ;:: 600mlll
B
110
600n1l11 > R 2: I.sOmm
c
69
I S01l111l > R ;:: 50llUII
D
22 x Jog
48
50mm> R
E
I I x: I O~
31
Near points of tangency of radius or in the weld or aI fusion boundary or me mber o r atlachl nenl
When weld reinrorccmclH is not removed: R ~
600mm
600mm > R ;:: 150mlll J 50mm
c c
69
D
48
69
At toe of the weld either alo ng edge of member or the attachment
> R 2: 500101
50mm > R
E
II
D
22 x JO~
X
101i
31
thickness attached by completcjoi nt - penetration groove welds su bject 10 tranSVCfse loading with or without longitud inal load ing when the detail embodies a transition radi us R with the we ld termination
ground smooth. Whe n weJd removed: R > 50mm
reinforcement
is
48
At toe of weld alon g edge of in weld (hinner material termination in SI11(1I1 mdius
31
E
R ?: 50mlll
At toe of weld along edge of thin ner material
When weld re inforcement is nol fCmoved :
E
II x 10'
31
Any radius
National StrucllJral Code of the Philippin es 6'" Edition Volum e 1
'SECTIONii'-" BASE METAL AT WtWEJ)TJUNSVE8SEMEMBER'CONNECTlONS 6.2
~ (0'
--~ (b)
\
- -
~ (e)
6.3
~ Ie)
~ (d)
I\ssociation of Structural Engineers of th e PI1ilippines
:r1!~1~.4:~3.l (f!9I!~)
.'
Stress Calegory
Description
. :: ."j.,::" . ,:.: ~:
. F$Ui!ile' i)i\sIi!n;:Pa~meters
....
:~p.'tr:'::
Thres hold f'm
Constant
C/
'\'\'"
PUlcllIial Crack
Init iation Point
.or
SEQUON;/i ;4'BASE META:LA'I'WELDEO TRANS~RSE;MEMBER·CONNECT[ONSJCifimil) 6.4 Base metal su hject to
]ollgilu di nul stress al lntllSYcrsc members. wit h or wit hout l r a n .~vc rsc stress, illIachcd by lilk'l Of ran ia l penetration groove welds parallel to direction of stress whellthe detail
In we ld Icnninalion or from
embodies a tranl>ition radius. R. wi th
the IOC of the we ld ex tendi ng into member
the weld terminati on ground smOOlh :
D
22x 10'
4&
E
II x 101
31
R > 50mnl R 2::5011l1ll
SECTION 7 - BASE METAL AT SHORT .:\TTACHMENTS1 7. 1 Base metal subject to iongih.:dinaJloading at details atlachcd by fillet welds parallel or tra ns verse (0 the di rection of stress where the de ta il e m bodies no tnmsitioll radiu s and wi th detail lengt h in direct ion of stress, a, and auachment height norma l 10 the surface of the member, b: a < 5001111
69
C
44 x 10"
50mm ::; a ::; 12b or 1000101
D
22
a> J2b or JOOIllIll when b is :5 25mm
E
II x l Oll
a> 12b or IOOmm when b is > 25mm
E'
3.9 x 10'
7.2 Base metal subjcct
48 X
10
In the member ctt the end of the weld
M
31
18
\0
lo ngitudinal stress at detail s ::Iuached by fi lle t o r parti:-tl ·jointpenetrati o n g roove welds, with or with ou t transverse load on detail. when the detai l embodies a transi ti on. R. wi th weld termi nati on ground smooth :
In weld te rmination extendi ng inlo member D
2 x 101i
48
Ii
II x lOS
31
R> 50111111
R 5 S0mm 1
I .
Attac hments" as used herein. is defi ned as any steel detail welded to a member which, by ils mere presence and independent of ils loading. causes a discOl~il1uity in the stress now i~llh c member and thus redu ces Ihe fati guc resistance . ..
National Structural Code of tile Philippines 6
th
Edition Volume 1
Steet and
Melal~~
Illustrative Ty P!C,\ '" I LX
6.4
Ss (dl
(b~
. Association of St'ructural En glneers of the Philippines
Descri pi i on
Iniliation Point
CHtegory "','
8. 1 B:I.~c melal ill s l ud~lypc she'lr con nCClOrs ilH:lchcd by filici or clcclric s tud welding .
8.2 She,lr on throat of corHinu ulIs ()r intcrmitlc nt longil udinal o r
44 x I
c
AI toe of wcld in basc metal
150 xJO LO
F
Iransvcrse fi llct we lds . or slol welch.
69
E
(Eqn A -3-2)
In Ihro<11 of weld
II x I
31
At end of we ld in b;lSC lIlet:.!
150
[ high. strcngth holt s. COllllll on bali s, threaded anchor rods and han ger rod s with cui , ground or rolled threads. Stress rangc all tensile stress area due to li ve l oad plus prying acti on when applicable .
F
(Eqn A -3-2)
55
AI fay ing surface
E'
3.9 x 10'
48
A t the root of the [hreads extending into the ten sile stress area.
th
Nolional Structura l Code of the Philippines 6 Edition Volume 1
Il tuslralivl! Typical Examples
8.1
8.2
-.. c.?~~, fa)
.~~~. :::-
~, (b)
8.3
---~
-_._.._.._---_
..........
_-- -_......._._._----,----- - - - - _ . _----_._._...._...._...._ -_.
8.4
8.5
ti?-(d)
L -_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ __ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ ___
Association of Stru ctural Engineers of tile Pililippines
.. _
CHArTE I~
FIRE BARIUER: ElcmcllI of con stru ction formed of fircresist ing materials ,1Ild lested in acco rd ance with ASTM Sl
5
Slel:1 all(f
Met~1
A 4.1.1 Performance Objective w
Structural components. members and building frame systems shall be designed so as to maintain their loadbearing function during the design-basis fire and 1O slII isfy olher performancc rcquirements specifil:d for the building occ up ancy. Deformmion critelia shal l be applied where the means of providing structural fire resistance. or the design criterill for fire barriers, requires co nsiderati on of th e deformat ion of the load-carrying structure. Within the compartment of fire origin, forces and deformations from the design basis fire shall not cause a breach of hori zontal or vertical compal1mentati on. A-4.1.2 Des ig n by Engineering Analysis TIle analysis me thods in Section A-4.2 arc permitted to be
used to document the anti cipated performan ce of steel framing when subjected to desig n-basis fire scenarios. Methods in Section A-4.2 provide evidence of compliance with perfonnancc Objectives established in Secti on A-4 .1.1. The analysis methods in Section A-4. 2 are permj tted to be lIscd to demonstrate an equ ivalency for an alternative material or method, as permined by the building code. A-4.1.3 Design by Qualification Testing
The qualification testing methods in Section A-4.3 are permitted to be used to document the fire resistaJlce of steel framing subject lO the standardized fire testin g protocols required by building codes. A-4.1.4 Load Strength
Combinations
and
Required
The required strength of the struclUre and its elements shall be determined from the following gravi ty load combinat ioll: (A-4-1)
[0.9 or 1.2JD + T+ 0.5L + 0.2S PRESCRIPTIVE DESIGN: A design method that documents compliance with general criteria established in a building code.
where D
L RtSTRAINED CONSTRUCTION: Floor and roof assemblies and ind ividual beams in buildings where the surrounding or su pport ing stl1iclUrc is capable of resisting subst antia l thermal expansion throughout the range of an ti cipated elevated te mpera tures. UNRESTRAIN ED CONSTRUCTION: Fl oor and roof assemblies and individual beams in buildi ngs that arc assumed to be free to rotale and expand throughout th e range of ant ici pated elevated temperatures.
:;· 135
S
r
= nominal dead load = nominal occupancy live load ;::: nomi nal snow load nominal forces and deformations due to the design-basis fire defi ned in Section A-4.2.1
A lateral noti onal load, N; =O.002Y;, as defined
jn
Appendix
A-7.2, where Ni = notional lateral load applied at framing level i and Yi= gravity load fro m co mbination A-4-J acting on framing level i, shall be applied in combinati on with the loads stipulated in Equation A-4- 1. Unless otherwise stipulated by the authorit)' havi ng jurisdiction. D. Land S shall be the nominal loads specified in ASCE 7.
National S tructural Code of the Philippines 6'" Edition Volume 1
!)· n G
CHAPTEI1 5 StC'cl and Metals
A-4.2 Structural Design for Fire Conditi ons ul' Analysis It is permil{cd to design structural members, components
When the ana lysis met hods in Section A-4.2 arc used to dClllonslnltc ~1I1 equi va lency as an ah cfnat ive material or met hod as perm itt ed by a bui ldi ng code, (he des ign· basis fi re shall be determined in accordance with ASTM E 11 9.
Table A-4.2.1 Properties of Steel lit Elevated Tem Jeratures Sh :d Tt lll f)('r& lur('
('FII'C)
)20 193 1204 13 16
399 427) 538) 649 )
17601 87 1) 19821 11 0931 11 204 1
.
k,;",E.,.I£
1.00 0.90 0.78 0.70 0.67 0.49 0.22 0.11 0.07 0.05 0.02 0.00
/ty::: / ·,..JF1
·· ·
1.00 0.94 0.66 0.35 0 .16
0.07
O.o.,
0.02 0.00
/t " ", F... / f ,
.. 1.00 0.94
A-4.2.1.2 Pust-fl ashovt.'" Co mpartm ent Fires Where the hea t release rm.c from thc fi re is sufficient to callse fl ashover. a post " f1 a~h()vc r (';omparlmCIl1 fire shall be assumed. The detc'rmination of the Icmj>eralurc versus Ii Ille pro fil e resu lt ing fro lll the fin.: shall include fue l load, ve nt ilati on cha rac teristics In Ihe Spil(';(" (natural .and mechanical ), compan rnelll dl nlcnsJons and thermal t'har;:tl'!cristics of the cornpilrLlllCJlI bounda ry. A-4.2.1.3 Exterior Fires The exposure of eXlcrior structu re ( 0 names projecling from windows or other wall openings as a result of a postflashover companmenl lire shall be considered along wit h the rad iatio n from the interior fire through the opening. The sha pe and length of the fl ame projec tion shall be used along with the dis tance between the flame and the ex terior steelwork to determine (he heal flux LO the steel. The met hod idclH ifi ed in Section A-4.2.1.2 shall be used for desclib ing the charac teri stics of th e int crior co mp arlment fire. A-4.2. I.4 Fire Duration The fire du ration in a parti cular area shal! be determ ined by considerin g the tolal combustible mass, in othe r wo rds. fuel load ava ilable in the space. In the case of eit her a locali zed firc or a post-flashover compartment fire, Ihe time dura ti on shall be determined as the total combusti ble mass divided by the mass loss rate, except where determined from Seclion A-4.2. 1.2.
0.66
0.35 0.16 0.07 0.04 0.02 0.00
... Usc ambient pro >ertie5.
A-4.2.1.S Active Fire Prote('.tion Systems The efrcels of
Where automatic smoke and heal ve nts are installed in nonsprinklered spaces, the resu lting smoke temperature shall be detenn ined from calcu lation .
A-4.2.1.1 Localized Fire
Wh ere the heat release rate from the fire is insuffi cient 10 C,IIISC nashover. a localized fi re exposure shall be ass umed. In sllc h GISeS , the fuel composition, arrangemem of the fuel array ami nnnr area occupi ed by the fuel shall be used 10 dete rmin e the radiant hea t flu x from [he n ame and smoke plume to the slmcture.
A-4.2.2 Temperatures in Structural Systems "der }i'ire Conditions Tempera tures within structural members, components anJ frames due to the healing condi tions posed by the des ign. bas is fire shall be determined by a heal transfer analysis.
Associalion 01 Structural Engineers 01 lhe Philippines
"
Tuble A-4.2.2 Properties of Conc"ete at Elevated TemperatUres '
A-4.2.4 Stru ctural Design Requireme nts
(;ulu: n .-Ic Tl'lI1lH'nllun'
A·4.2.4.1 General Stru ctural Integrity The structural rrame sl);111 be c"pable of providing adl!
k.
=F<- IF.
I~.II'•.
t', . ( % )
NWC 1.W<: _ ffil"CI c- I .we 1.00 .-I<~~---~----u.;j3~ ~~ 11J .1 ]
=
_ () ,~~_
I.UO
--":=F.i~IL ._~~ .... _g:.~.~. ____I . ~~__. - .--0.75 ..•.--12HH)
1~1 61_"_
1'271 1.538) 1(49)
17601 IR71) 19R21 110931 (12M)
- ..
..
_-
0 .71 0 .54
~-
0.21 0.10 0.05 0.01 0.00
0.46
0.6 1
- i)5l1..-'::
0.98
0.57
0.85 0.71
0.38 0.20 0.092 0.073 0.055 0.036 0.018 0.00
0.62 O.RO I.Of> .1.32
O.H6 OX!,
_ ....
(J,34 ._--
LOO
0.58 0.45 0.31
0.18
0.05 0.00
1.43
1.41) -1.50
Con tinuolls load paths sha ll be provided to transfer a!l force.; from the exposed region 10 the final poi nt of rcsisl
1.50
A-4.2.3 Malcrial St rengths at Elevated Temperatures Malcrhd propcJ1ics at elevated temperatures shall he dClcmlincd rrolll lest data. In the absence of such claw. it is permillcd tn use th!! material pro perties stipulated in this section. These relationships do not apply for steels with a yield streng th in excess of 448MPa or concretes with specified compressio n strength in excess of 55 MPa. Thermal expansion of structural and reinforcing steels: For calclilmions m temperatures above 65°C, the coefricicnt of thermal expansion shall be 1.4 x I O~/
expansion shall be 7.9 x JO'I·C. A-4.2.3.2 Mechanical Properties at Elevated Temperatures Thc deterioration in strength and stiffness of structural members, components, and sys tems shall be taken into accou nt in the structural analysis of the frame. The values r~\7111 Film, Em. f _CIII, Ecm and Lnl at eleva ted tcmperature to be used in s(llJctural analysis. ex pressed H....
the r
I'or lighlweighl cOllerele (LWC). values of lju shall be obtained from tests.
A·4.2.4.2 Strenglh Req uirements a nd Deformation Limits Co nformance of the structural sys tem to these requirements .; hall he demonstrated ~y constructing a mathematical model of the structure based 011 principles of structural mechanics and evaluating this model for the internal fo rccs and deformations in th e mcmbers of th e structure developed by th e temperatures from Jhe design-b asis firc. Individual members shall be provided with adequate strength to resist the shears, axial forces emu moments detclll1ined in accordance with these provisions . Connecti ons shall develop the strength or (he connected members or the forces indicated above. Where the means of providing fire resistance requires the considerati on of deformation criteria. the deformation of the structural ~)'S lCIl1. or members thereof, under the design-basis fire s hall not exceed the prescribed limits.
A·4.2.4.3 Methods of Analysis A-4.2.4.3a Advanced Methods of Analysis The methods of analysis in thi s secti on arc perm ill cd for the des ign of all steel building strll ctures for firc co nditi ons. The design-basis fire exposure shall be lhat determined in Sct:lioll A-4.2.1. The ana lysis shall include both CI thermal response and the mechani cal response to the design-btlsis fire . The thermal response shall produce 11 temperature field in each structural element as a result of the des1t!ll-hasis fire and shall incorporate temperature dependent thermal propenies of the structural elements ilnd lire-resistive materials as per Section A-4 .2.2.
The mechanical response results in f(lfCl:S and deflections ill the structural sys tem subjected to the thermal response calculated from the desi gn-basis firc. The J11 cr.;hanical
National Structural Code of U"le Philippines 6
111
Edition Volum e
!; 138
CHAPlEH 5· Sleel a nd Metals
responsc shall take into
Tension members
It is permined to model the thermal re sponse of a lCIl Sioll clemcnt using a onc·dirnensiona! heat transfer equation with heal input as directed by the design -basis fire defill ed ill Secti on A-4.2.1.
The des ign st rength of a tcnsion mcmber shall be dct ermined usi ng the provisions of Section 504. with steel properties as sti pulated in Section A-4 .2.3 and assumin g it unifonn temperature over the cross section using the temperature equal 10 the maximum steel temperature. 2.
C;ompression members
It is pemliHed to model the thennaJ respon se of a compression element using a onc-dimensional heat transfer equation with heat inpu t as directed by the design-basis fire defined in Section A-4.2. I. The design strength of a compression member shall be determined using the provisions of Section 505 with steel properties as stipulated in Section A-4 .2.3,
3.
Flexural members
It is permiHed to model the thermal response of flexural clements using a ollc-dimensional heal tr:msfer equation to calculat e botlom flange temperature and to assume that this bouom nangc temperature is conSl<1nt ovcr the depth of the member.
The design strength or a flexural member s.hall he determined usi ng the provisions or Section 506 wilh steel properties as stipulated in Section A-4.2.3. 4.
Composite floor members
dimcnsiOll
or a composite llexlIfil l member shall be determined using the provisions of St!ction 509. wilh reduced yie ld slrt!sses in th e sleel consistent w i t!~ the (emperature varimioll described under thermal response. The design strength
A-4.2.4.4 Design Str ength The design strength shall be dClennined as in Section 502.3.3. The nominal strength. Rn. shall be calculatcd using material proper1ies, as stipulated in Section AA.2J. al the temperature developed by the dcsign -bnsis lire. A-4.3 Design by
Qualjftc~'lion
Testing
A-4.3.1 Qnalification St;\Ildards Stru ctunl! members and compone nts in steel buildings shall be C]unlified for th e ratin g period in conformance wilh ASTM El19. It shall be permitted to demonstrate co mpliancc with these requirements using the procedures specified for steel construction in Section 5 of ASCE/SFPE 29.
A-4.3.2 Restrained Cons truction For Ooor and roof asse mblies and individual bemus in buildings. a restrained condition exists when the surrounding or suppor1ing stmcture is capable of resisting actions caused by lhermal expansion throughout [he range of anticipated elevatcd temperatures. Steel beams, girders and rrames supporting concrete slabs that are welded or bolted to integral framing members (in other words, columns, girders) shall be considered restrained constmclion .
A·4 .3.3 Unres trained Constru ctio n Steel beams, girders and frames that do nOl support a concrete slab shall be considered unrestrained unless the members are bolted or wclded 10 surroundin g cOl1stlllcti w. that has been specifically dcsigned and detailed to re~.; '.: actions caused by therm al ex.pansion.
A steel member bearing on a wall ill a single span or at the end spa n of multiple spnns shall be considered unreslrain c(! unless the wall has been designed and detailed to n·: :.. , effec ts of therma l expa nsion .
It is permitted to model the thermal response of flexural elements supporting a concrete slab using a one-
Association of Structural Engineers of the Philippines
A.'pPEND,Jx: A.S . . EVALUATtON:QFEX1STING
STR . uCttJRES <,," ": ... . "
" . .
This appc.ndix applies to lhe evaluation of the strength and stiffness under sIalic ve rtical (grav it y) loads o f existi ng s truc tures by Sl fll t'l ural anal ysis. by load le!>ls, Of by .1 combination of struc tura l cuwlysis ,lIld load lests when specified by the cnginccl"-o[· rccord or ill the con:raCI docum ent s, For slIch evaluation, th e steel grades afC not limi lCd to those li sted ill Section 50 1.3.1. This appendix
docs not address load testi ng for Ihe effects of seismic loads or moving loads (vibrations).
ava ilable, th e us c uf app licable projCt.:1 records ~haJ! he pcrmi Hcd to rcducc or eliminate the need for IC!-i ting. A-S.2.2 Tt'nsilc Proper ties Tensi le properties or members shall be considered in
evaluati on by stnl clu ral analysis (Secti on A· 5 . ~) Of load tc~;(s (Secti on A-SA). Such propcI1ies shall include the yield stre ss, (ensi le strength and percellt elongat ion. Where avai lable. ccnified mill test reports or CCrlified rcporiS of tests made by the fabricator or a te sting la bo rat ory in accordance will' ASTM A6/A6M or ASD8/A568M, as
applicabl e, shall be permitted for this purposc, Otherwise, tcnsi le tcsts shall be conducted in accordance with ASTMA370 from sa mples cu t from components of lhe structure.
The Appendix is organi zed as follows : A-5.1 A-5.2
A-5.3
A-S.4
General Provisions Material Properties
A-5.2.l Determination of Required Test A-S.2.2 Tensile Properties A-S.2.3 Chem ical Composition A-S .2.4 Base Metal Norch Toughness A-5.2.5 Weld Melal A-S.2.6 Bolls alld RivelS Evaluation by Structural Analys is A-5.3. 1 Dimensional Data A-5.3.2 Slrenglh Evalualion A-5.J.3 Serviceabi lity Evaluation Eva luation by Load Tests A-SA.' DClermina(ion of Load Rating by Testing A-5.4 .2 Serviceability Evaluation A-5.5 Eva lu ation Reron
A -5.1 General Pro visions These provisions sha ll be applicable when the evaluation of an ex isting sleel structu re is specified for (a) verificati on of
a specific set of design loadings or (b) determination of the avai lable strength of a load resisting mClnber or system. The evaluation s hall be perfonncd by st ructural analysis (Secl ion A-53). by load lesls {Seclioll A-5A}, or by a
co mbination of structural analysis and load test s, as specifi ed in the contract documents. Where load tests arc used. the ~ n gi l1 eer-of- record shall first <1 nalyze the $I I'llCl urC . prepare
The e ll g ine er-o f~rc cord shall determin e th e specifi c lests Ihm are required from Section A-S.2.2 lhrough A-S.2.6 and specify th e locations where they arc required. Where
A-S.2.3 Chemical Composition Where we lding is 31l1icipated for repair or modificalioll of exis tin g structures, the chemical com pos ition of the steel shall be deter mined for use ill preparing a welding procedu re specificat ion (WPS). Where available. resuhs from cCI1ificd mi ll test reports or certi fied rcpor!.') of lests made by lhe fabric.nor or a tes ting laboralory in
Where welded tension splices in heavy shapcs and plates as defi ned in Section 501.3. 1d are critical to the performance of the structure. the Charpy V-Notch toughness shall be determ ined in accorda nce with the provisions of Section 50 1.3.1 d. If til e notch tou ghness so determin ed docs not meet the provisions of Sect ion 50 1.3. 1d , lhe engineer· of· record shall determine if remed ial actions are required. A-S.2,S Weld Metal
\Vh ere structura! performance is dependent on existing we lded connections, representative sa mples of weld metal shall be obtained. Chemical analysis and mechanical tests shall be Ill
classified accordingly. Altemalively. the assumption that Ihe bolls are ASTM A307 shall be permilled. Hivels shall be lh
National Structural Code of Ihe Phili ppines 6 Edition Volume 1
~) · 140
C HAPTE:r~ ~;
. Steet anti Met als
assumed IU he ASTM A502, Grade I, unless a higher grade th rougil dOcUIHclHation or testing.
i s csw hli shcd
A-S.3 Evaluation by Strueturnl Analysis A-S.3.' DimclIs ionnl Data
All dimensions lIsed in Ihe evaluation, such as spans, column heigills, memher spaci ngs, bnlcing locati() lIs, cross sectio n dimcllsioJ)s, thicknesses and connecti o:. dct ai ls, shall be detcrmined fmlll a field survey. Alternatively, when available, it shall be permitted 10 determine such dimensions from appli cable project design or shop drawings wilh field verificati on of cri tic.:al va lucs. A-5.3.2 Strength Evaluation Forces (load effects) ill members and co nnectiolls shall be determined by structllral analysis appli cable to the type of stru cture evaluated . The load effec ts shall be detcrmined for the loads and faclOred load combinations stipul ated in Secti on 502 ,2. The ava il able st ren gth of members and connections shall be determ ined from il pplica blc provisio ns o f Sections 502 through 5 1J of this Speci ficalion . A-S.3.3 Serviceability Evalualion
Where required, the deformati ons at service loads shall be calcul ated and repo'ned , A-S.4 Evaluation by Load Tests A-5.4.1 Determination of Load Rating by Testing To detennjnt the load rating of an existing Ooor or roo r stru cture by testin g, a test load shall be applied increment al ly in accorda nce wi th the engineer of record 's plan. The Slnlclure shall be visually inspected for signs of di stress or imminent failure at each load level. Appropriate measures shall be taken if these or any othe r unusual conditions are encountered.
The tested strength of the structure shall be taken as {he ma ximum applied test load plus (he in-sit u dead load. The live load rating of a fl oor stru cture shall be dete rmined by
such as member dellcctiulls, shall be monito red at criti cal
locati ons during Ihe test, referenced 10 the initiLl I position before loading, It sball be de!ll onstfil tcd, while ma int aining maximuill test load foJ' Olle hour that the deformation of the structu re does not in crease by more than I () percent above that ,II the beginning o f the holding period, It is permissible 10 repeal the seq uence if necessary to demonst rate co mp liance. DefoJ'IllHtions or the s tru c t~lre shall also be reco rd ed 24 hours after the test loading is removed to determine the amount of perm anent set. Because the "mounl of acceptabl e permimcnl deformat ion depends on the specific structure. no li mit is specified for permanent de formation at maxi mum load ing. Where it is not reasible to load {cst the entire structu re, II segme nt or l onc of not less th an onc complete bay, representative of the most crilical conditions, shall be selec ted. A-S.4.2 Serviceability Evaluation Wh en load tests arc prescribed, the SlruClU rc shall be loaded increment all y 10 lhe servi ce load level. Deformations shall be monitored for a peri od of aile hour. The structure shall th ell be unload ed and th e deformation recorded. A· 5.5 Evaluation Report
After the ev,alua ti on of an existin g structure has been co mpl eted, the engineer-of-record shall prepare a repon documentin g the evaluation. The report shall indicate whethcr the evaluation was performed by structural anal ys is, by load testin g or by 11 co mbination or structural ana lysis and load testing. Furthermore. when lestin g is pcrfonned. the repon shall include the loads and load combination used and the load-deformat ion and timedcfOJ:lllation relationships observed. All relevant information obtained from design drawin gs. mill test reports and auxiliary material testing shall also be reported , Finally, the report shall indicate whether the stmc{urc, including all membe rs and connecti ons. is adequate to withstand the load effec ts.
setting the tested strength equal to 1.2D + 1.6L, where D is th e nominal dead load and L is the nominal live load ratin g for the structure. The nomjnal live load rating or the noor stnlctu re shall nOI exceed th at which ca n be calcul ated using applicable provisions of the spccification . For roof structures, Lr, 5, 01' R as defined in the Symbols, shall be substitut ed for L. More se vere load combin ati ons shall be used where required by thi s code. Peri odic unl oading shall be considered once th e service load level is attained and after the onset of inelastic structural behavi or is identified to document the amount of permanent set and the magnitude of the inelastic deformations. Deformations of the structure, Association of Structural Engineers of Ihe Philippines
, .', ~.;~)i"':'_~f.~tf. • ; _",.:•• \ 'J
.'i":i·,~):
C i IAprUl
~i
~.
Sii2(::1 and Metal
141
'1l1C rcqu ired br:lcc JriJj;I('.)·.\· is
fl,,,
1(21' )
A[21',) ,
[J,,, = " - --
= - - ' (I..RFD ) 0 \ I.},
. L,.
(AS !)
(A-n-21 This appendix addre sses the minimum brace .')trcnglh and stiffness necessary 10 provide member strengths based 011 th e unh :~c('d length betwccn braces with all cfTcctivc length factor. !" {'qual to l.O .
where ~
L" The appcndix is organizcu
.IS
n
= 0.75 (LRFD)
= 2.00 (AS)))
:; disliUlce between bnlccs, in. (mm)
follows: For desig n according to Section 502.3.3 (LRFD)
A-6.1 A-6 .2 A -6.3
General Provisions Columns Bcams
p,
Usrr' Note: The requirements for the stability of braced[rall le ~ystems are provided in Section 503. The provisions
required axial co mpressive slrength using LRFD load combin .tliOils. N
:=
For design according to Section 5023.4 (ASD) p,
in Jus appendix apply to bracing. intended to stabilize
:::. required tlxiai compressive strength using ASD load combinati ons. N
in, ljvidual members.
A·G.3.2 Nodal Bracing
A . 6.1 General Provisions H I acing is assumed 10 be perpendicular [ 0 th e members to r..~ braced; for inclined or diagonal bracing, the brace ~ trength (force or moment) and stiffness (fo['ce per unit Ji splace ment or moment per unit rotation) shall be adjusted for the angle of inclination. The evaluation of the stiffness
ThL~
required brace strength is 1',,, = O.() J P,
The required brace stiffness is
4
[J,,, = Q ( 81' ) (AS!)
furn ished by a brace shall include its member and gcometric properties. as well as the effecls of connecti ons and anchOling detail s.
(A·6·4) ~
Two general type~ of bracing system s arc conside red, relative and nodal. A relati ve brace cont rols th e movement of lhe brace point with respect to adjacent braced poin ts. A nodal brace controls Ihe movement at the braced poinl wit hout direct interaction Wilh adjacelll braced point s. The ava ilable strength and stiffness of the brac ing shall equa l or exceed the required limits unless analysis indi c at es thai smaller values arc justified by analysis.
A seeond~order analysis that includes an initial out~of straightness of the member to obtain brace strength and stiff~ess is permitted in lieu of the requirements of this appendix.
A¥6.2 Columns It is permined to brace an indi vidual col umn .11 e nd and intermediate points al ong its le ngth by either relat ive or nodal bracing systems. h is assumed that nodal braces arc equall y spaced along the columll.
A-6.2 .1 Relative Bracing
The required brace strength is
= 0 .75 (LRFD)
n
= 2.00 (ASD)
For design according to Section 502.3.3 (LRFD)
P,
:=
required axial compressive slrenglh using LRFD load combimuions. N
for design according to Seclion 502.3.4 {AS D) PI'
:; required axial compressive strength using ASD load combinations, N
When Lb is less than I...t/, where /..,q is the maximum unbraced length for the required column force with K equal to J.O. then IAI in Equation A~6 -4 is pcrmiued to be taken equal to /..q A·6.3 Beams AI points of suppon for beams, girders and tnlsses, restraint against rotation about their lo ngitud inal axis shall he provided . Ream bracing shall prevent the relati ve di splacement of the top and bottom flanges. in other words , twi st of the secti on. Lateral stHbility of beams shall be
provided by laleml (A-6- 1)
(A·(,.})
braci ng, torsional
bracing or a (Q doubJr.
combination of the Iwo. In members subjected
th
National Structural Code of the Philippines 6 Edition Volume 1
curvature bending, the in!lcclioll pOin! shall not be <.:onsidc n:d a brace point.
:::: required flexural strength using LRFD lCld
combinations, N-m/l)
A·6.3.1 Lntcral Bracing
For design
Brac ing shall he .ulachcd Ilcar Ihe compression flange. execpt for II c31lfilcvcred member, where an end brace shall be illliIchcd ncar the lOp (tcm ioJl) flange. Luera! bracing stull I be mUlched 10 hOlh nanges at the brace point nearest lhe inllcclioll poinl for beHIllS subjected 10 double c ur valure be nding along the length 10 be brHced.
M.·
ncxufill strength combinations, N-IllIH
= reyuired
When Lit is less than M". then Lh in
using
AS!)
itud
u,. the m:'ximulll unbraccd lcngrh for
Equatio!l A-6-S shull be permilled to be taken equal to ! "/. A-6.3.l.Ia Relative Ilntcing The required brace stre ngth is (A-6-5) The required brace stiffness is
not be attached ncar the compression flange . Th ,.~ conncction bet wcen a torsional brace and the beam shall b ~ able 10 support Ihe required mo ment g iven below. (A-6-6)
where
$ = 0.75 (LRFD)
A-6.3.2 Torsional Uracing II is pennillcd 10 provide either nodal or cO lllinu~':> us tors ional bracing along (he beam length. It is pe rmitted 10 attach (he bracing al any cross-sectional location and it nC t! d
Q
A-6.3.2.2a Nodal Bracing The required bracing moment is
= 2.00 (ASD) M/u
iz"
Cd
LI,
:::; distance between flange ce lllroids, mill :::: 1.0 for bending in single curvature; 2.0 for doubl e curvature; Cd = 2.0 only applies to the brace closest to the infl ection point =- laterally unbraced length. mill
= required flexural strength using LRFD load combinations, N-mm
= required
flexural strength combinations, N-mm
using
(A-6-
nCbLb
The required cross·frarne or diaphragm bracing stiffness i·;
fir)
(A- u- :(-.
AB = [ 1- -
For design according to Section 502.3.4 (ASD)
Mr
_0'_ 02_4M-,-,L-,-,
9)
For design according to Section 502.3.3 (LRFD)
M,.
=
ASD
load
fiscc
where
A
=~(2.4LM':)(LRFD) Pr =0.(2.4LM':)(ASfiJ IIElyC IIElyC. "
(A -G- II)
A-6.3.1.1 b Nodal Bracing
The required brace strength is
(A -6- i:O )
(A-6-7)
.where
The. rcq uircJ brace stiffness is
$ = 0.75 (LRFD)
(A-6 -8 )
$ = 0 _75 (LRFD)
= 3.00 (ASD)
User Note: Q = 1.521$ = 3.00 in Equation A-6-11 bee_us" the moment term is squared.
L
where
Q
!2 = 2.00 (ASD)
For design according to Section S02 .}.3 (LRFD)
l\.::so::.:iation of Structural :::n9ir.eers
= span lengt h, mm = number of nodal braced poinls wiLhin the :-: ~ .
= modulus of elasticity of steel = 200 000 i\ :. ' = out-of·plane mornelll of inertia, mm~ = modification fRctor defined in Section 506
or the Pililippines
I",
= beam web thic kness.
t,
= web sl i/fcncr thickness, mm
fJ,
= stiffener width for one-sided slifft'ncrs (usc twice the individual stiffener width for flilirs of stiffe ners ). 111m = hrace stiffness excl udin g web disto lli oll. N-mm/radia n = web distortional sliffncss, including th l! effect of' web transverse stiffeners, i f any. N·mmlradiiln
/if
Illlll
= required flexural strengt h using LRFD load combinati ons. N-mm
= required Ilcxura! strength combinat ions. N·1ll1ll
The appendix is organized as follows :
A·7.3
General Rcq uirclllcllts Noti onal Loads Design·Analysis Constraints
A-7.1 General nequircmcnts Mcmbers shnll satisfy the provisions of Section 508. 1 with
f or design according 10 Section 502.3.4 (ASD)
M"
Thi s appendi x addresses thc direct :!J1alysis method for st rw..'llInli sys t ~ms compri sed of moment [nunes. braced frames. shear walls, or combinalions the reof.
A·7.1 A·7.2
For design according to Section 502.3.3 (LRFD)
Mr
APPENDIX A·7 DIRECT ANALYSIS METHOD
usin g ASD load
If B.uT < PT. Equation A·6· IO is negati ve . which indicates that tors ional bea/JI bracing will not be effective due to inadequa te web distorti onal stiffness. When required. the web stiffener shall extend the full depth of the braced member and shall be aHac hed to the flange if the torsional brace is also altached to the flange . Alternati vely, it shall be permi ss ible to stop the stiffener shon by a distance equal lO 4(,,· frolll any beam flan ge that is not directly attached (Q th e torsional brace. When uJ is Jess than Lq. then Lb in Equati on A-6·9 shall be permitted to be taken equal to i.,q .
A-6.3.1.2b Continuous Torsional Bracing
For continuous bracing, use Equations A-6·9, A-6·JO and A-6· 13 with Un taken as 1.0 and LII taken as l .q; the braci ng moment and stiffn ess are given per unit span length . The distonional stiffness for an unsliffencd web is (A·6-l3)
the nominal column slrcngths. 1'". determined usin g K = 1.0. Thc required st rength s for members, co nnecti ons and other structural elemelHs shall be determined using a second order elastic annlysis Wilh the cons traints presented in Secti on A·7 .3. All componenl and connecti on dcfofmtll ions that contribute to th e IHlcral displacement of the structure shall be
cOl1sidcrc<.l in the ana lysis. A· 7,2 Notional Loads
NOlionalloads sha ll be applied to the lateral fr aming system account for the effects of geometric im perfections. inelastici ty, or both. Notional load s arc lateral loads that arc applied at each framing level and specified in terms of the gravity loads applied at that level. The gravity load used to dc(cnn inc the noti onal load shall be equal 10 or greater than the gravity load associated with th e load combination being evaluated. Notional loads shall be applied in the direction that adds to the destabilizing effec ts under the specified load co mbination. (Q
A-7,3 Design-Analysis Constraints
I. The second -order analysi s shall consider both p·o and p .6. effects. It is permitled to perform the analysis lIsing any general second· order analysis method. or by the amplified first·order analysis method of Section 503.2, provided that the 81 and 8 2 [Helors are based on the reduced sti ffncsses defi ned in Equations A·7-2 and A·7 ·3 . Analyses sha ll be conducted according to the design and loading requirements specified in either Section 502.3.3 (LRFD) or Section 502 .:1.4 (ASD). For AS D, the second-order analysis shall be carried out under 1.6 times the ASD load combinations and th e results shall be divided by 1.6 to obtain the required strengths. Methods of analysis that neglect the effects of P-o o n the lateral displace ment of the struc ture arc permitted
National Structural Code of the PhilipPInes 6 Edition Volurm~ 1 1h
where the axi.!l loads in all members whose flexural sliffllcsscs ,Irc considered to l'olltributc to (hc lillcral stability of the structure satisfy the following limit : OPr
< 0.15P,·/.
(A ·7·) )
shall he uscd for all
~
= required axi.t/ COl lpressivc strenglil under LRFD
Pl" .
or ASD load com~l;lla!ions, N 1 = rc EJI/}, evaluated in the plane of bending
/"
/'y
2.
a = 1.6 (ASD)
A nOlionalload. M = 0.002Y;. applied independently in two orthogonal directions, shall be applied as n ItlI('ra l (oad ill all load combinations. This load shall be in addition to other latcral loitd s, if an y,
= noti ollill I
I I
J.() for al', /P)'~ O .5 ;: : 41 ap,.IPr (l-aPrll'.\")J for 0.1', IP y > 0.5 ~ 1"I.~4uircd axi,lI compressive strcrigth under tUr/J or ASD load t.:ombinations, N . :::;: APr, lllC'mber yield strellc,h, N
and
where
,
mOIll(,.IlI of inertia "hou t the ,Ixis or hCIlJing, 4 Jl1m
=
:lIld
a = 1.0 (LRFD)
The llolitllHti Ivad ltldl icicnl of {Ul02 b h
(1
= 1.0 (LRfD)
4.
A rr.!duccd axial stiffness, fA 1,: ,
IA·7·) )
shall be lIscd for members whose axia l s tiffness is <';ollo;;idcred to cont ribute to the lateral stability of :11t"" struclUrc. whcre A is the cross~scctiollal mcmber area.
\'.'hO!I"l' 111. ralio of set:ond-nrdC'1" drir. :0 fi r~I' III or less than 1.5. it j ., jlCI 'li i~.i ihlc tu app ly Ihe Iltli l on;I/ 10il.:l. Ni, as :.t minillllllll l:ucl"::1 ioml for "IOIIl1\',
order Jrifl : ~. {·.qua l
the gril\ it~ ·unly JO;ld nJillbinationl'
For illl
it I~ permissible III lI~e Ih(' \i~"ulllcci ~'ul·()r !,'.("ollldry in the anal)'!.\ {)f ~. tn! :·P II "~ In ]it'll
L·;b(,S.
plllmblH.' ~~
nw
of <..Ipplyinr, ;s noliollal load or a minimum !:tIc-lid loud defined :Ihm·c.
User Not e: The unreduced stiffncsses (I ~I ilnd AF) af(' u.;r.d in the above c~klliation s. The rat i,) 1)1" ~cco lld - ()nkr drift 10 first-order dJifi can be represented by H2. ;1" cOl.klll ill :?d using Equation 503.2-3, AllCm<1tivd y. Iht~ f
3.
A reduced flexur:1I stiffness, EI*,
Ei' = O.8t" EI
a = 1.6 (ASD)
In lieu of using '[I, < 1.0 where aPr /1\ > 0.5. tit = 1.0 Ill:l)' be lIsed for all members. provided 111<11 an additive not io nal load 01"0.00 1Yiis added to the nOlio!lalload rcqllircd in (2).
Where a ~m;lI!l~r a~sul1!cd ollt-of-plu;llhlles~ j ", justified , th e no tioliallo;ld l..."ocfTi cil..."II' may be ad"ll" ll.'d plOponiullHlly.
For
whose t1cxunll stiffness is I hr'
where
where
PI
lllelllbcr~
(onsidercd to cOnlributc to the lateral stabilit y of structure,
(A· 7·2)
AssociBtlon 01 Structmal Engineers of the Philippine s
"r
PART2A
..i
I,
SEISMIC PRQVI~tQN 11'OR, STRUCTURAL S'i1EEL BUILDINGS SYMBOLS
A,
Cross-SCCliOllni
K I. L L
L"
(VBE), mm2
flange arc
Gross area, 111m2 CroS!i-scctional area of the s truc tural steel core,
111m2 Area of the yielding segment of steel core, rnm2 Minimuill arca of tic reinforcement , mm2 Hori zontal area or the steel pl ale in compos ite
sheaf wall, mm2
A"
Area of link stiffener, mm 2
A".
Link web area,
C" Cd
Ratio of required strength to available strength. Coefficient relating relative brace stiffness ilnd
1ll1ll2
L, M"
M,,,
curvmurc
C" C,
D
D
E E E £I
I', If
Deflection amplification Parameter lI sed for determining the approximate
fundamental period Dead load due to Ihe weighl of the structural clements and pc nnanelll features on the building. Outside diamcter of round HSS. mm E:,u1hquakc load EfreCl of hori z.ontal and venical earthquake· induced loads Modulus of elasticity of sleei, 200,000 MP" Flexural clastic st iffncss of [hc chord mcmbcrs of the special segment, N·mm2 Specified minimum yicld stress of the type of steel to be used, MPa . As used in the Specification, "yield stress" denotes either the minimum specifi ed yield poinl (for Ihose Sleels that ha ve a yield point) or the specified yield strength (for those steels that do not have it yield point) Fy of a beam, MPa Fy of a column, MPa Specified minimulll yield stress of the ties, MPn Specified minimum yield strc::>s of the steel core, or aewal yield stress of tile steel co re as determined from a COHPOJltcst, MPa Specifi ed minimulll tensile strcngth, MPa H cight of story, which may be takcl1 as the distance betwee n the centerline of Iloor framing al each of the levels above and below, or the dislnnce between the top of Ooor slabs aI each of the levels above and below, mm
I
Moment of inertia, mm4
Moment (If im:11ia or
IlUll
Diswllcc between VilE cCI1[CrIiIlCS, mill Length between points· whkh are ei ther braced against lateral <.lisplaceiiu!1lI or compression flange or braced against twist of the cross section, mill Link length. 111m Clear diSlnncc between VUE flanges, mm Distance between plastic hinge locations, 111m Limiting laterally unbraced length for fuli plastic flexural strength, uniform momenl case, rom Limiting laterally unbraccd length for plastic: analysis, Illlll Length or the special seg ment , mm Required nexural strenglh, using ASD load combinations, N·lTun Additional moment due to shear amplificntioll from the local ion of the plastic.: hinge to the colullln ce nterline based on ASD load combi nati ons, Nnun
M" M,,,
M " MI'" M,•,•
Nominal flexural strength. N-mm Nominal flexural strength of the chord me mber of the special segment. N·mm Nominal plastic Oexural strength , N·mtn Nominal plastic flexural strength modified by ax. ial load, N-mm Nominal plastic flexura l strength of the beam, N-
mm Expec ted plastic moment, N-mm Nominal p l a~ilic nexural strength of the column, N-mm
M, M ..,.
Expected nexural strengt h, N-1ll11l .. Additional moment due to shear amphfical1ol1 from the location of the plastic hinge to the column ce nterline based on LRFD load combinations, N111m
M"
P,,,.
P,.
P" P"
Required flexural strength, using LRFD load co mbinations, N-mm Expected requ ired flexural strengt h, N·m111 Required axial strength of a column usjn~ ASD I oad combinaliolls, N Required compressive stfength lI sing ASD load combinations, N Required strength of lateral bmce ;It ends of the link, N Available axi:11 strength of a column , N Nominal axial strength of a column , N
Nominal compressive strength of the composi te column calcul ated in accordance with the Specificalion, N
National Structural Code of the PhilipPules 6
1h
Edition Volume 1
Nomina! axial compressive strength of diagonal members or the special segment, N Nomina! axial tensile strength of diagonal
(/
b
members of the special segment, N
Nominal axial strength of a composite column at zero cccc!Hricity, N
P F r,
Required compressive strength, N Required compressive strength using ASD or LRFD load combinations, N Required axial strength of a column or a link using LRFD load
P" P",
combinations, N
Required axial strength of a composite column, N Required compressive strength lIsing LRFD load
d d d, d:
combinations, N
e
P,
Nominal axial yield strength of a member, equal to fy Ag, N
/"
P l I,
Axial yield strength of steel core, N
Ii /I"
R,
R" R,
R,
V" VII<.
v"
Maximum unbalanced venical load effect applied to a beam by the braces, N Axial forces and moments generated by at least 1.25 times the cxpected nominal shear strength of the link Seismic re~ponse modification coefficient Nominal strength, N Ratio of the expected tensile strength to the specified minimum tensile strength Fu, as related to overstrcngth in materia! yield stress Ry
II
II
Required strength
Panel zone nominal shear strength Ratio of the expected yield stress to the specified minimum yield stress, Fy Required shear strength using ASD load (·olllbinations. N Nominal shear strength of a member, N Expected vertical shear strength of the special seglllent, N Nominal shear strength of thc steel plate In a composite plate. shear wall, N Nominal :--hear strength of an active link, N Nominal shear strength of an active link modified by the axial load magnitude, N Required .~hcar strength using LRFD load combinations, N Distance from top of steel beam to top of concrcte slab or encasement, mm Mnxilllum distance from the. maximum concrete compression· fiber to the plastic ncutral axis, mill Plastic section modulus of a member, mm3 Plastic section mociulus of the beam, mm3 Plastic section modulus of the column, mm3 Plastic section modulus x~axis, mm3 Minimum plastic section modulus at the reduced beam section, mm3
II" I
r,
I"""
Angle thaI diagonal lllembers make with the horizontal Width of" compression clement as defined in Specification Section502.4. I. Ill!ll Width oj" COIUIllIl flange, mill Flange width, 111m Width of the concrete cross-section minus the width of the structural shape Ille;n" d pc:'p'.'ndicular to the direction of shear, 111m Nominal fastencr diameter, mm Overall beam depth, nlln Overall column depth, mill Ovcrall pancl zone depth between contiI1U;l.',' plates, mm FIJF link length, mill Spccificll compressive strength of concrete, lvl!'u Cle|
Thickness of web, mill Width of panel zone between column mm
x
Parametcr used for determining the approx;;;, .:::· fundamental perinci (I-R2)
Association of Structural En9ineers of the Ptlilippines
z./J
Minimuill plastic secti on modulus at the redu ced sect ion ,m m1 M0I11!.!1l1 (1\ beam and column cCllIcrii nc determ ined by projecting the slim of the nominal col ulllll pl:lslic mome nt strength , redu ced by lhc axial st ress Puc/Ago from the 101' and bo[\om of th e be illll moment connect ion MOllle1l1 at the intersection of the beam
column ccntCrliilCS determined by projecting the beam maximum developed moments f ro m the
column
/1 ,1
11/,
I I
! !
II II I I
!I r
face.
Ma xim um
developed
mom ents
shall be determined from {cst resu ll s. Co mpress ion strength atljwamcn t factor Design story drift Deformation qUtJlllilY used to co ntrol loading of tes l specimen (lOtal brace end rotation for th e
subasscmhlage lest spec imen; lowl brace axial Dcfortnlltiol1 for th e brace test specimen) I1bm V"luc of deformati on quamity, I1b, corresponding to the design story drift I1by Value of defo rm ation quuntity. 6b,
DEFINITIONS ADJUSTED BRA CE STRENGTH.
Strengrh of' a brace
ill a hucklillg- rcslraincd braced frame at dcJol"ln;tliolls c.:o rrcsponding to 2.0 times the design story drift. ALLOWABLE STRENGTH. by the safcty faclor. Nil / n.
Nomi na! strengr h d ivided
NSCH CODE. Build ing code under which {il e structure is designed. NSCP 6,h Edi 'ion,
AMPLIFIED SEISMIC LOAD. Horizon'a! componen, of earthqu,lke load E mult ipli ed by no, where E and the horizontal component of E arc speci fied ill the NSCP code. AUTHORITY HAVIN G JURISDI CTIO N (AHJ ). Organization. political subdivision. oftice or individual charged with th e responsibi lity of administcring an d enforcing th e provi sions of this standard. A VAILABLE STRENGTH. nllowablc st rength , :IS appropriate .
Design
strength
or
ASD (ALLOWABLE STRENGTH DESIGN), Method of proponio ning structural components suc h th al tile allowable strength equals or exceeds the requi red stre ngth o f th e component under the action of thc ASD load co mbin at ions . ASD LOAD COMIJINA TION. Load combinarion in 'he NSCP code in'ended for allowable streng,h design (al !owable srress design). BUCKLING-RESTRAINED BRACED FRAM E (IlRBF). Diagonally braced frame saflsfyin g 'he requircmellts of Section 529 in which all members of the brac in g system are subjected primarily to {lxial forces and in which the limit statc of compression buckling of braces is prec luded at forces and deformati ons correspondi ng to 2.0 times the design story drift. BUCKLING-RESTRAINING SYSTEM. Sys tem of restraints that limits buckling of the steel core in BRBF. T hi s syste m includes the casing o n the sleel core and structural cJC111CrHS adjoining its connections. The buckli ngrestrain ing system is intended to permit the tran sverse cxpans ion an d longitudinal contraction of the steel core for deformations concsponding to 2.0 ti mes {he design story drift.
CASING. Elemcnt that resists forces transverse
to
the axis
o f the brace thereby re~ trailling bllckling of th e core . T he casing requires a mea ns of delivering thi s force (0 thc
remainder of the buckling-restraining systelll. The casing resists little or no fo rce in the axis of the brace. th
Ncltional Struclural Code of the Philippines 6 Edi\ion Volume ·1
s.§
5· 148
CHAPTER 5
Sf0.Ul [lnd r...-ietais
COLUMN BASE.
Assemblage of pla (c~, cOl1nC,~·lO r s. bolis, and rods at Ihe base o f a column lIsed to tra nsmit
EX PEC TED YIELD STRENGTH. Yield slrength in te ns ion o f a member, equal 10 the expecLed yie ld sI!'css
forces bClwcenlhe steel superstructure and the foundatioll.
mul ti plied by A. .~.
CONTINUITY I' LATES. Column stiffe ners al II", top and bottom of the panel zo ne; also known as transve rse
EXPECTED TENSILE STRENGTH. Tensile strenglh 0.1' a mem ber, equal to the specified minimum tensile strengt h, Fu, mu ltip lied by R,.
stiffeners. C ONTRACTOR. Fa bricalor or ereClOr. as app li cable. DI<:MAND CIUTI CAL WELD. Weld so designateD by these Prov isions.
EXPEC TED YIELD STR ESS. Yield stress of Ihe material , equal 10 th e specilicd minimum yield stress, Fy, mullipl ied by R,. . INTERMlmlATE MOM ENT FUAME (1M F). Momcnt
DESIGN EARTHQUAKE. The earthquake represenled by Ihe de sign response speclll llll as specifi ed in the NSC P code.
frame sys tem that meets th e re qui remcllLs or Sect ion 523. I NTERSTORY DRIFT ANGLE. InlerSlo.ry displacement
divide.d by story hei gh t, radians. DESIGN STORY DRI FT. Ampli fied story drift (drifl un der th e desi gn earthquake, including the effccfs of inelastic action), determined as specified in the NSCP code. DESIGN STRENGTH . Res is tance factor multiplied by the nominal strenglh,
INYERTED-V-BRACED FRAME. Sce V-braced r,.am e.
K-A n EA. The k-arca is the region of the web that extends from the tangent poi nt of the web ilnd the flange-web fi llet (AISe 'Ok" dimension) a distance uf 38 lllm into the web beyond the " k" dimens ion.
DIAGO NAL nn-ACING. Inclincd stru ctural members carrying primarily axi al load that arc empl oyed to cn
mccting
the
K-BRACED FRA1\-'1E. A bracin g co nfiguration in which braces COllllect to a colum n a( a location with no diaphragm or other OUt-of-plane SUppOI1. LATERAL BRA C ING ME~mER. Member that is designed 10 inhihil Iment! buckl in g or !meral-tor sional buck lin g of primary fram ing 111~ll1b ers. LI~K.
In EBF, the segmc nt or it beam Ihat is located bClweclllhc ends two diagonal br;'iccs or between the end of a di ag on:!! brac e and il column. The length of the link is defined as the clear di st ancc between the end s of two diag o llaJ braces or hetwee n the di agona l brace find the column face .
or
LINK I NTERMEDIATE WEB STIFFENERS. Vertical web stiffeners placed within the link in EBF. LINK ROTATION ANGLE. lnelmaic angle between thc link and the beam outs id c of the li nk whcn Ih<.' to\,tl story drirt is equal to the des ign story drift . LI NK SHEA R DESIGN STR ENGTH. Lesser of the avail able ~ hear slrength or the link developed rrom the mo mcnt or sheilI' strength of the link. LOWEST ANTI CIPATED SERVICE TEM PE RATURE (LAST). The Io.west I-hour average tem perature with a IOO-year mean recurrence intcrval.
FACTOR
RED UCE D BEAM SECTION. Redu ction ill cross scc,ion
DESIGN). Method of proportioning structural component s
LRFD
(LOAD
over a discrete len gth that promotes a i.O!le or inelastici ty in
such that the design st rength equal s or exceeds th e required strength of the component under the HClion of the LRFD
the member.
load combi nations.
AND
.
RESISTANCE
REQUIRED '
LRFD LOAD COMlIlNATION. LO<1d combination in 'he NS CP code intended for strength design (load and resistance factor design).
STRENGTH.
Forces,
sli-esses.
and
deformations proulIl:cd in a structural co mponent, determined by either stru ctur<11 analysis, for the LRFD or ASD load combinations, as appropriate, or as specified by the Specification and these Provisions.
MEASURlm FLEXURAL RESISTANCE. Bending momelll mea sured in a beam at the f;lce of the column, fo r a bea m-to-column tcst s pecimen tested in accordance wilh Section B-4.
RESISTANCE FACTOR, 'I). FaclOr ,ha, accounl s fur unavoidable dev iations of the nominal strength from the actual st rength and for the manner and conseque nces of fai lure.
NOMINAL LOAD. MagnilUde or 'he load s pccificd by 'he NSCP codc.
SAFETY FACTOR, n. Factor that accounts for deviations of the actual strength from the nominal strengt h, deviation s of the actual load from the nominal load, 1I11certailltics in th e analysis thnt transform s the load into a 10;:ld erfect and for the manne r ,JIld consequences or fail ure.
NOMINAL STRENGTH.
Slrengl h of a slnlclurc or
com pon ent (without the resist ance ractor or sa fely factor
applied) to resist the load cffecls t as determined in accordance with thi s Specification. ORDINARY CONCENTRICALLY BRACED FRAME
(OCBF). Diagonally braced frame- meet ing the requiremcnts of Scction 527 in which all members or th e brndng system arc subjected primarily In axial forces. OlWINARY MOMENT FRAME (O~11'). M lllllcll! li'ame syste m that meets the rc quiremcnts of Section 524. OVERSTRENGTH FACTOR, QO. FacIOI' spcci lied by th e NSCP code in order to determine the amplili cd 'iC'ismic load, where req uired by these Provi sions.
SEISMIC DESIGN CATEGORY. ClassiOcalion assigned to a building by lhe NSCP code based upo n its seism ic ll Se. group and the des ign spec tral res po nse acce lcnnioll coefJicicnt s. SEISMIC LOAD RESISTING SYSTEM (SLI~S). Assembly of structural e lements in the building that resi sts seismi c load s, incl udin g struts, l:ollectors, chords, di aphraglns and tru sses. Seismic respomic mudilication coeflkicnl, R. Facto r that reduces seismic load eCfects to strength leve l as specified by the NSCP code.
SEISl\1lC USE GROUP. Classification assigned to a structure based
PREQUALlFIED CONNECTION. COI1I1«lion compli es with the requiremen ts of Section B-J.
PROTECTED ZONE. Area or l11emb",,, in whi ch limitations apply to fabrication and .auac hllll.~ Ill S . Src Section 520.4, PROTO TYPE. The cOl1neclion or brace design Ihat bc used in the building (SMF, 1MI', EBF, and BRBF).
Oil
its use as specified by the NSCP code.
,hat
IS lO
PROVISIONS. Refers to thi s document, and in reference' to the AISC Seismic Provisio ns for Structural Steel Buildings (ANSIIAIS C 34 1). QUALITY ASSURANCE PLAN. Wri((cn dcscrip'ion or qualifications, procedures, quality inspections., rcsouru: s\ and record s to be used to provide assu ralll.:n Ihal Ihe st ru ct ure compl ies with the engineer's qua lit y rcqu:rcmcllls, specificat ions and con trac t doc uments.
SPECIAL CONCENTRICALLY BRACED FRAME (SC BJi'). Diagonall y braced frame meeting the requirements of Sectioll 13 in whi ch all members of the bracing system ,1i1~ subj ected prirmll'il y lO axial forces. SPECIAL MOMENT FRAME (SMF). Momen! frame system that meets th e requirem en ts of Section 522. SPECIAL PLATE SHEAR WALL (SPSW). Plalc shcar waIJ system that meets the requirements of Section 530. SPECIAL T1WSS MOMENT FRAME (STMF). Truss mOllll!1l1 frame system (hal meets rhe rcq ui re mcllls of SCCliotl 525, SPECIFICATION. Refers 10 'hc AIS C Specific", ion for S'nlcl ural S'eel Buildings (ANS I/A IS C 360).
[i ··ISO
CHAPTFri (S ~ St()(:t and fvh)[aL;
STATIC YIELD STRENGTH. Strength of a structural member or connection determined on the basis of testing conducted under slow monotonic loading until failure. STEEL CORK Axial-foree-resisting clement of braces in BRBF. The steel core contains a yielding segment and connections to transfer its axial force to adjoining clements; it may also contain projections beyond the casing and transition segments between the projections and yielding segment. TESTED CONNECTION. Connection that complies with the requirements of Section B-4. V-BRACED FRAME. Concentrically braced frame (SCBF, OCBF or BRBF) in which a pair of diagonal braces located either above or below a beam is conn ccted to a single point within the clear beam span. Where the diag 011<;1 braces are below the beam, the system is also referred to as an inverted-V-braced frame. X-BRACED FRAME. Concentrically braced frame (OCBF or SCBF) in which a pair of diagonal braces crosses ncar the mid-length of the braces. Y-BRAClm FRAME. Eccentrically braced f!'ame (EBF) in which the stem of the Y is the link of the EBF system.
PART2A SECTION 514 STRUCTURAL STEEL BUILDING PROVISIONS 514.Scopc The Seismic Provisions for Structural Steel Buildings, hcreinafter referred to as these Provisions, shall govern the dcshw, fabrication and erection of structural stcel members and '-'connections in the seismic load resisting systems (SLRS) and splices in columns that arc not part of the SLRS, in buildings and other structures, where other structures are defined as those structures designed, fabricated and erected in a manner similar to buildings, with building-like vertical and lateral lond-resisting-elemcllts. These Provisions shall apply when the seismic response modification coefficient, R, (as specificd in the NSCP code) is takcn greater than 3, regardless of the seismic design category, When the seismic response modification coefficient, R, is taken as 3 or less, the structure is not required to satisfy these Provisions, unless specifically required by the NSCP code. These Provisions shall be applied in conjunction with Chapter 5 Steel and Metal, hereinafter referred (0 as the Specification. Members and connections of the SLRS shall satisfy the requirements of the NSCP code, the Specification, and these Provisions. Wherever these provisions refer to the NSCP code and there is no local building code, the loads, load combinations, system limitations and general design requirements shall be those in SEllASCE 7,
Part 2A includes H Glossary that is specii1cally applicable to this Part, and Section B-1, B-2, B-3, B-4, B-5. B-6and B-7
Association of StnJctural Engine81'S of the Philippines
CH APTEH G
SI0(~!
8nd jvk;i<11
5·151
SECTION 515 REFERENCED SPECIFICATIONS, .CQl)ES~ AND STANl)A.llliS
SECTION..!;16 GENE:RAI;.sE~~MIC DESIGN REQUIREMENTS
The documenls refcrencto in these Provision s shall include those listed in Specification Section 501.2 with the following additions tlnd modifications:
Thc required strength :md other seismi c provisions for seismic Zones 2 and 4 including limilations on height and irregularity shall be (IS specified in the NSCP code.
American InstilUlC of Sleel Construction (AISC)
The des ign story drift shall be determined as required in the NSCP code.
Specification Jor Structural Steel Bllildillgs, ANS/IA/SC 360·05 Prequlllified COllnections for Special (llld Intermediate Sleel Momem Frames for Seismic Applications, ANSIIA/SC 358-05 Ameri c,lil Society for Nondes tTucti ve Testin g (ASNT ) RccOJl1Jnendcd Practice for the Training and T esting of No ndestru ctive Testin g Personnel, AS NT SNT TC- I a-200 1 S tandard for the Qualifi cation and Ce rtifi cati on of Nondestructi ve Testin g Personnel, ANSIIAS NT CP- IS92001 Am erican \Vcldin g Society (A WS)
Standard Methods for Determination of the Diffusib le H yd rogen Content of Martensitic, Bainitic, and Ferrit ic Steel Weld Metal Produced by Arc Weldin g, A WS A4.393R
Standard Methods fo r Mechanical Testing of Welds-U.S. Customary, ANSII A WS B4 .0-98 Standard Met hods for Mechanical Testing of We lds-Metrie Onl y. ANSIIAWS B4.0M :2000 Standard for the Qualification of Welding l nspectors, AWS B5.1:2003 Describing Oxygen-Cu t Surfaces. A WS C4. 1 Federal Emergency Management Agency (FEMA ) Recommended Seismic Design Criteria fo r New Steel Moment -Frame Buildin gs, FEMA 350, Jul y 2000
National Struclu ral Code of tile Ph iljpp in(~ ~; 6~i""i [clition \lolurn o
"1
517.1 Loads and Load Combinations The loads and load co mbinati oll s shall be as sti pulat ed by the NSCP code. Where amplified seismi c loads arc requ ired by these Provisiolls, the horizontal pon ioll of the e;u1hquakc load E (as defi ned in the N S.(P code) shall be multiplied by the ovc rstrength factor. Q u. prescribed by the NSC P codc. 517.2 Nominal Strength The nomi nal strength of systems. members and conllections shall co mpl y with the Specificmion, ex<:epl as l110diried tllroUghout these Provi sions.
S18. 1 Structural Design Drawings and Sr~ ecifi ca fiol1s SlnlclurllJ design drawings and spcci ri c~ltions shall show the work \0 be performed , and include items required by the Speci fi cation find Ihe following, as app licable:
I.
Desigllalion of th l! seismi c load resisting syst em (S LRS)
2.
Designation of the members and connections thaI are part of the SLRS
3.
Configuration
4.
Connec ti on materia! speci ri c!llions Hnd sizes
~.
Loca ti ons of dema nd critical wc lds
6.
Lowesl anli cip<.ned service temperature (LAST) of the sleel stru cture , if the structure is not enclosed and Illaintained at a Icmpermure of JO °C or higher
7.
Locations and di mcnsions ofprotcctcd zones
8.
Loc<.H ions where gusset pl ates arc accom modate inelastic rotation
9.
Weld ing requirements as specified in Secti on B·6, Section I3·6.2 .
o{"
the con necti ons
10
be detai led to
Uscr Note: These Provisions should be consistent witlLtlie Code or Siandard Praclice, . s designaiM in Section 501.4':(i( Ihe Specifica tion. There may be specific connections . ~fl appHcitiiins 'for 'which 'details aretiol specifically:a d " by O,e ' Provisions. If such a condinon exists, 'ihe .c documents ·'spould 'inclu& appropriate requirerri~ those ipplicitlions: Th~e may ind ude ' .'nondeS .. testing requii-ements beyond those in Section B-2i :b'Ql( fabrication requirements beyond those pennitt~ bY ".'5~~ Specification. bolting requirements other than those' j n
5 I 8.2 Shop Drawings Shop dr'lwings shall incl ude items requi red by \he Specifi ci:ltioll and (he following, ,IS applicable: I.
Designation of the members and co nnect ions thal arc pa,1 of the SLRS
2.
Con necti on matelial specifications
3.
Locations of demand critical shop we lds
Association of Structural Engineers of Ibe Philippines
4.
Loc;lliol1S and dimcnsions of protectcd
5.
Gusset plates drawn 10 scale whcn tlley arc detail ed m:cc)JlllllodalC inelasli<.: rotation
6.
Welding rcquircmcnls as speci fied in Section B·6, Secli on B-2.2.
ZO IlC:'; \0
519.1 Material Spccific.~tions Structural steel uscd jll the seis mic load resisting system (SLRS) shall Illccllhe fl::qu ircmcms of Specificati on Section 50 1.3.1 ;1, excepl as modified in these Prov isions. The speci fi ed Ininimlllll yield sH'ess of steel \0 be used for members in wh ich inelasti c bchavio!" is expec ted shall 110t exceed 345 MPa for sys tems defined in Sect iolls 522, 523. 525. 526, 528, 529, and 530 nor 380 MPa for syslems defined in Sections 524and 527, unl.css the suitability of the material is determined by testing or oIlier rational criteria. Thi s limitation docs nOt apply to columns for which the only expected inelastic behavior is yielding at the column b'ISC.
518.3 Erection Drawings Erection drawings shall include ilems requi red by the Specification and (he [ollowing, as applic.lble: I.
Designa(i on of (he members and cOllnections that arc pari of Ihe SLRS
2.
Field connection material specifications . lIld sizes
3.
Locati ons ofdernalld criti ca l field welds
4.
Locat ions and dimensions of protected zones
5.
Loca ti ons of pretensiolled bolts
6.
Field welding requireme nts as specified in Secti on B·(), Seclion B-2.3
User Note: 'TIlere may be specific connections and applications for which delails are not specifically addressed by the Provisions. If such a condition exists, the erection drawings should include ·appropriate requirements for that application. These may mclude: b-oltirig requirements other than .those in the RCSC ·SpecificatioJi for" Stiucturiil Ioints Using A,STM - A325 or A490 .:·Bolts, and.. :welding r~uirc;\llents other than tliose in SCIOtion B-6. See Section Mf . '::ule Specification for · R.dditional pro~ision; on erection drawings. ' .
of
The struclUral steel used in the SLRS described in Sections 522,523,524,525,526, 527. 528, 529 and 530 shall IllCCI o ne of the fo ll ow ing ASTM Specifica lions: A361 A36M. A53/A 53 M , A500 (Grade B or C). A501. A529/A529M, A572/A572M IGrade 42 (290 Mpa), 50 (345 Mpa) or 55 (380 Mra» ), A588/A588M, A913/A913M IGrade 50 (345 Mra), 60 (415 Mpa) or 65 (450 Mpa »), A992/A992M, or A 101 I HSLAS Grade 55 (380 Mra). The struclural 'Iccl used [or column base plates shall meet onc of the preceding ASTM specifications or ASTM A283/A283M Grade D. Other steel s and non-stcel ma terials in buckling-restraincd braced frames arc permitted to be used subject 10 Ihc requiremellls of Section 529 and Section 8-5. User Note: This sec\io~ only.,coyers malerial prqperties for strUClural sleel used in !be SLRS ai,d included in the 4etjffip.9-B 8~ , ~,u,uCI'!f"l . s~"¥t, I'!Y~\l io ,.~,Cflion of .~,e AISC, G.oo~ .of,1\tand;tr(aG!icc. (:jthetsteel; snch as cables fQrpe@.~;'\ bn;~il)g, [s'n;( ilJiOiud¢. '. ' .. .
n
519.2 Material Properties for Determination of Required Strength of Mcmbcrs and Connections When required in these Prov isions, th e required strength of an element (a member or a con neclion ) shall be delcnnjned from the cx:pecled yield stress, R)" F,., of an adjoining member, where Fy is the specified rninimum yield stress of the grade of stecl to be used in the adjoining members and RI. is th e ratio of the expected yield stress to the specified 1l1inimum yield stress, "~n of lhal material .
National Structural Code of the Pililippines 6'" Edition Volume 1
. Talil~ Sl~·l
Rv and
. ......
.._ ______.._.~E£!.iE.i!~'2~ _ __._____ __ ~L_ lint -roiled slnK' lu rid shapes and bars: • AS TM A36/36 M • ASTM A 572/572M Grade 290 ASTM A572/572 M Grad e 345 or 380 ASTM A9 13/A9 13M Grau e 345 ,4 15,450 ASTM A588/A588M ASTM A992/A992 M . AIOII HSLAS Grade 380 • ASTM A529 Grade 345 • ASTM A529 Gmde 380 Holl ow structura l sections (HSS) ASTM A500 (Grade B or C) , ASTM A501 Pi pe • ASTM A53fA53M Plat es • ASTM A36/A36 M • ASTM A5721 A572M Grade 34 5 ASTM A5881 A588 M
·
t
I
S l9.3l1 cavy Section CVN Hequir(l l1lenfs
Ri ValueS ctit Different Meril/lcr.T;,nes
·
1.5 U 1.1
Rt .-
J.2 1.1 1.1
1.2 1.1
1.2
IA
1.3
1. 6
For structu ral steel in the SLRS, in add iti on (0 the rcqu ire mcnt s or Spccif'icatiol) Section 501.3. k. hoI rolled shapes with na ng!.!s 38 I1lIll thick and th icker shall have 11 minimum Charpy V· Notch toughness 01'20 f't · lb (27 J) a\ 70 lIF (2 J DC), tested in the alt erna te core loca tio n as describcd in ASTM A6 Supplclllcillilry Rcquirement S30. Plates 50 I11Ill thick and thi cke r shal l ha ve II minimum Cha rp y Y ~ Notch toughocss of 20 ft ·l b (27 J) at 70 ' I' (2 1 ' c) , measured .1I any locHti oll pCI~jnittcd by ASTM A673. where the plate is used in the following:
I.
Members built-up frolll platc
2.
Connection plmes where inelastic strain under seis m ic loading is expected
3,
At the steel core of buckling-restrained braces
1.2
1.2
1.3
J.2
1.1
1.2
User Note: Examples of connection plates where inelastic behavior expected include. but are not lim ited to . g'u sset plates intended to func ti on as a hinge and allow Oll t-O( plane buckling of braces, some bolted flange plates for moment connections, some end pl ates for bolted moment connections. and some column base plates designed as a pin
is
The available strength of the element, rpR" for LRFD and R,/ Q for ASD. shall be equal to or grea ter than the required stre ngth, where R" is the nomin;.11 st rengt h of the connecti on . The expected lensil e strength , RfF", and the ex.pected yield stress, R. F\, arc permiltcd to be used in lieu of F.. and FI>
respectively. in dClcnni ning the nominal strength. Rno of rupture and yie ldi ng limit Slales wi th in the same me mber for wh ic h (he requ ired strength is dctcnnined .
User Note: In several instances a member, or a coniIe'~Jjon li mit state within that member, is required to be designed for forces corresponding to the expected strength of- the member itself. Such cases include brace fracture limit states (block shea r rupture and net section fracture in the brace in SCBF), the design of the beam outside of the link In EilF, etc. In suC;h cases it is permitted to use the expected material st rength in the detennination of availab le member strength . For connecti ng elements and for other members. specified matetial strength should be used. The values of HI' and R, ror various stee ls are given ill Tnbl e 5 J 9· 1. Other v.~ l ues o f RI , and RI 51mll be permitted ir the values arc determined b)' testi ng spccimcns si milar in s izc and source conducted in accordHl1cc with the req uire mc nts ror Ihe specified grade s tee l.
or
or
Association of Stru ctural Eng ineers of the Philippines
(;:1-11\1) 1En s
Sleel ,lild Metal
S 1SG
SECTION 520 CON.NJJ:GPONS, JOINTS, AND
normal to the force resisted by welds, such as a moment connection in which welded flanges .transmit fJe~ure and a bolted web transmits shear, is not considered to be sharing the force. .
520.1. Scope
520.3 Welded Juint s V·lclding shall be performeJ in accordance with Section B· 6. Welding Shilll be performed in accordance wilh it welding procedure specificatio n (WPS) as required in AWS DJ.I
FASTENERS
Con nections, joirHs :IIlU fasteners Ihal arc P,1I1 of the se ism ic.:
(SLRS )
shall
Specification Section 510, and requl rcmellts of th is Section.
load
resisting
sys tem
with
,om pI)'
the
with
additional
The design 01" connections for a member thai is a pan or tile
Illanu f [leI urer.
SLRS shall be configu red such IIial ..I ductile limit slale in
either the co nll ection or the member cOlltrols the design . User N~te: An example of a ductile limit state is tension yielding. It is unacceptable to design connections for mcmbers that are a part of the SLRS such that the strength limit state is governed by nonductile or brittle limit states, such as fracture, in either the connection or the member. 520.2 lloltt'd Joints All bolts shall be prctcnsio ncd high strength bolls and shall meet lhe rcquircrncllls for s!iIH .Ti[icnJ rayin g surfaces in accordance wi th SpcdficiHi o ll Section 510. J.8 with a Class A surface. Boils shall he installed in standard holes or in short- sloHed holes perpendicular to the applied load . For brace diagoll
Th e laying sill/aces for (,lid plllle II/omelll COIIIl(XliOI/!i ore permirred to be COaled with comings 110( tested for slip rcsi.\'/allce or with cOOling.\' lI'ilh a .\"lip coejJici(J11I /('.\',\' 1/1011 11/(/( (~ra Class Af(lying sUI/ocr. Bolts
520.3.1 General Requirements All welds used in mcmbers and cOJ)llcetions in thc SLRS Sllldl be mmle wi th a filler metal that ca n produce welds that have a minimum Charpy V-Notch lOughncss of 20 fI-lb (27 J ) a! 0 ('F (minus 18°C), as determined by th e appropriate AWS A5 classification test method or manufacturer certi ficiHiOl)' This requirement for notch toughness shJII ,ll so apply ill other cascs itS required in these Provisions . 520.3.2 Demand Criticul 'Velds Where welds arc designated as dcnHmd cri ti cal , they shall be mad e with
User Note: Welds designated demand critical arc specifically identified in the Provisions in the section applicablc to the designated SLRS. There rnay he spccific welds similnr 10 those designated as demand cri tical by these Provisi ons that ha ve not been specific~l ll y identified as demand critical by these Provisions that warrant such designation . Considerati on of lhe demand criti cal designation Cor such welds should be bnsed upon the inelastic strain demand and the consequence
U
National Structura! Code of tile Philippines G ' Edition Volume 1
of failure. Complclc-joint-pcnelfillion (CJP) groove welds between columns and hase plales should be considcred oem,lIlo criticlll similar to colulIlll splice welds, whcn CJP groove welds llsed for COIUIlIIl splices ill th e desig nated SLRS ha ve bcc n designated dcmand crit ical.
I 1
pm special alld intcrmediate moment frumes. typica l ex.amples of delll
CJ P groove welds: I.
Welds of beam flanges to columns
2.
Welds of single plale sJlcar conncc ti ons to col umns
3.
Welds of beam webs to col umns
4.
Column splice we lds, incJuding colum n bases
Por ordinary moment frames, Iypica l exa mpl es incl ude Cli> groove welds in items 1, 2, and 3 above .
!; f
I,
!
Association of St ~uctura l Engineers of the P hil ippines
'I- . . 4,) . .'." , ';' ;1 . '
,m.':: ~;. ,
::. ;\~,~-S' ;.: ~ :~~~~:~.;. . ,:;,;,.,
hit
- - ..- -bit
- -.,---,,-,-.,---,, --c--_\--- -. --
Uniform compre ssion in ilangc:s of rolled or buill-up t·
sharx:d:;cl'liom/b]'lhl -";~:~j~~'~c~(:;~~:el~:on in l1:mgcs Qf rolled or built-up I·
_
Unifo rm cOlllpn!ssi()11 in fla nges of channels. outstand in g
:~f~:r pairs of ang les ill continuous contac t, ;j nd braces
__ :~
hll
. ....
,"',
O.38jE[F;
1- - ·-- - - - - - -- -- ---1-
- -- - --1 O.30 .fEli~
1'111
do uble lingle me mbers wilh sc pc ralOrs, or Oang.cs of ices
'. "
lS i Uniform compression in
,.-
0.30JE/Fy
--- -- - -- -- -- - - - j - - - -- - -- - - -- - --1
~ ~;~J~J,a~,~I'~f~ "';~~:,'c~,7.~.I ;'l,-'-'I-~re-'--'.7i-o-r~'-,7·,-,~le- -g.-~, o~r;,~h-,-g7.--,c~-a-'-'-g. 7,-C-,-.,~,--c.-g--,.- <-,7,-.--·~--=--- ----.-----.--..·---.~~~~~-"1,~,~, '.:.~ ~~~~~-~--==t=========~=~j2t.5~-~=~=========~
'.'·;:.:.\:.:. . .·.:.;.·....: " '" .,.~ ;.
O.JOJ E/Fy
- - j- - -- - - ' - -. -- ---j
Unlfo"" comp", ,,lo,, I" ",nges of H-pll' 'C<~li(-m-'-----\-------·I-,'-'------+-----O-.4-5-.fEi-;=E=1'~F=>~'- - - - - j
." ,
_;.i~.·~
Flexure in !langes of fOiled or Imill -up l-shilJX:d scl'lions:
l'l.lel.lel.l sl.lhl
SiC Ill:.
(J f Ices 19l
Webs in flexural co mpn:ssion in 522 .unlt-ss noted o lher .....ise
OC,tlllS
hIt
O.30ji IFy
till
a.3ofi IF,.
in S M F. Scct iull
2.4 5
hIt..
Webs in !1cxuraJ comprcssion or combin cd flc.'(ur(: and axial compression !u].[c ].!g],[hl,lij./j)
hl1\\'
.. -!!/
'F/t:y
V~ For C. SO .125[kl - - -- - -\
3.I,JEIFY (I . I.54 C,)
=~ •111)
.•
, . .,S '
"ii5 ..
; .... 'C! ...
:}~
For Ca > 0.1 25 IkJ 1.1 1 ,iEIFy
' en
'.
hII.
(2 .33·C, )
1.'9 Jf:IFY
Roun d HSS in axial and/or fl c.xurr flexural compression O.64/EIF" .leU.) bII or loll. ,
..
1-_ _ __-'--'W'-""b"s"of"'I"·I..:.P"'''"'''''e,,c,,tio,,'-' '' --_ _______ _ _
_ --'_____-',,,,,,"',_ ____.___-'-_ _____._a.9~ElFy}
[a j Req uired for bcrmillcd to usc J,. in spcc ilic:ltion Table 50 2,4 1 Required for br.ccs ilnd co lunl1ls in ScnF SCClion 526 and brat"cs in OCBF Seclioll 521 It is pemlillcd 10 use),. in Spocific:iU ion Table 502A.I fOt columns in STMF Section 522 and colllmils in EBF Seclio n 528 Req uired fOf link in EBF Seclion 528 CJ.cCpl iti is per millcd 10 use l.t in Ta ble 502.4. 1 of the: ~p;:ci ricalion fOI n:tnges of links or JcnSlh 1.6 M,fY pa re dcfill: <.l in Secl;l,\n 528 III Di ~gonal web mcbers with in Ihc s pecial segment of STMF Section 5ZS IsJ Cllord members of STM F SeClion 525 IhJ Requiled for beams and colu mns in ORlJF Seclioll 529 Ii) Required for colu lI1ns in SJ>SW Seelion 530 [j] For colum ns in STMF Section 522 c\llu(1)n ~ in SMI'. ;rthe (
fbi le J (d] Ie)
For C.
~0.125.
""= 3.76 'Ii £/FY(I .2..1S C.I
For C, :;:. 0. 125. >'r = 3.76 JE f FY (2.33· C.) ? 1,49 ,JEIFy
for ASD. C, = (0" 1'/1\1 where I ). ::: required compressi\'\! slr-cuglll (ASOJ. f'l f . = required comprcssh'C stlcngth ( LRFO). N PT a~i 3 1 yield strc nglh. N
=
~= O.90 Q~ -
1.67
1h
National Structura l Code of the Philippines 6 Edilion Volume 1
I~
158
CHAPTEF{ 5 · Sleel and Metals
For l!ccciltricilil y braccd frames (EBF). typic.!! cx;unpl cs of demand <.:n ti cal we lds include CJJ> groove welds betwc\!1l link b\!,UllS and columns. Other welds, such as those joining the web plale to flange plates in built·up ESr:- link bcams, and column splice welds when made using CJP groove welds, should be considered for designation as demand cri ti cal welds.
weld. II" a cu rved clip IS used. il s h.d l have :1 m i l. ;:~:; : ;:1 rad ius of 12 I1Ull. AI the end of th e weld udjaccnt to the column wch/lh ngl..' juncture, weld tabs for co ntinuity plates shall nut he lI st.'d. except when permitted by the e ngil1 cc r~ of~ rcco rd. U!l les~: specified by the cllginecJ'·of"·rccord Ihill th ey be I-C,!ll OVt'(L weld tabs shall not be removed when used in this locatiO:\.
520.3.3 Recommcll(l,d Joint
Tile usc of Type I welded joints is nO( allowed in seismic Zone 4. Type' II joints arc recommended as in the usc of Proprietary W ~~ l ded Joint . 520.4 Protected Zone
Where a protected zone is designated by these Provisions or ANSIIAISC 358. il shall comply wilh the following : 1.
Withi n the protected zone, discolllinuit ies created by fa bri cati on or erection operations, slich as tack welds, erection aids; air·arc gouging and thermal cutting shall be repaired as required by the engineef·of· record.
2.
Wt~lded shear studs and decking Httachmcilts til at penetrat e Ihe beam flange shall not be placed on beam fl anges within the protected zone. Decking arc spo t welds as required to secure decking shall be permitted .
3.
Weldcd, bolted. screwed or shot·in attachments for perimeter edge angles. exterior facades. panilions, duct work, piping or other construction shall not be pl aced within the protected zone.
E.rception :
Welded s"eor studs and ot"er ('0,,"ectioIJ5 s"all be permiued when desigllated ill the Prequalijied Connections f or 5iJecioi and Intermediate Momelll Frames for Seismic Applications fANSIIAISe 358), or as Ofherwise determined in accordall ce with a conrl eetioll prequo/ijicatiofl ill accordance wilh· Section B· 1, or aJ determined ill (l program of qualification testing in accordan ce wilh Section 8·4.
Outside the protected zone, calculations based upon the expected moment shall be mnde to demonstrate the adequacy of the member net secti on when connectors th at penetrate the member are used. 520.5 Co ntinuity Plates and StifTcncrs
Corners of continui ty plates and stiffeners placed in the webs of rolled shopes sholl be clipped as desc ribed below. Along Ihe web, Ihe clip shall be deloiled so Ih a! Ihe clip ex lends a distan ce of at least 38 nllll beyo nd the published k detail dimension for the rolled shape. Along the flange. the c lip shall be delailed so Ihal lhe clip does nOI exceed 0 di slOnce of 12 mm beyond Ihe published kl delail dimen sion . The clip shall be delailed 10 facililale suilable weJd terminations for both the flange weld and the web Associa tion of Structural Engineers of the Philippines
CHAPTE·. ll
SJj)~'flQN;5,21 ' MEMBE~ ;.·
or Sections for Locailluckling
52L2,1 COlllp"ct When requi red by Ihese Provisions, members of the SLRS shall have flanges continuously connected to the web or webs (lnd dlC width -t hickness r
clements shall
nOI
~}·159
52 I .4.1 General
Members in the seismic load resisting syste m (SLRS ) ~ha ll compl y wilh the Spccitic'lIioll and Section 521. For col umn s that arc !lot pari of the SLRS, sec Sect ion 52 J. J .2. Classifita~ion
Sleel and Metal
521.4 Column Splices
521,1 Scope
521.2
[j
The requi red strength of colu mn splices ill the seismic load resi!'>ling sys tem (S LRS ) shall equal [he required st rength of Ihe COI Ullll1S. including that determined from Sections 521 .3, 522.9,52).9,524.9,526.5 and 529.5.2.
III addition, welded colum n splices th aI are subj ect 10 a calcul ated net ten si le load effect dctcnn;ilcd using th e load co mbinations st ipulated by the NSCP code including the am plilicd seis mi c load, shrtll salisfy both of the foHowi ng requirements:
J.
Th e available strength of partial-joint-penetration ( P1P)
groove welded joillls. if used, shall be at least eq ual to 200 percent of the required strength.
exceed the limiting width-thickness:
r:ltios, ).'). from Specific:llion T'lblc 502.4 . 1.
2.
The available strength for each nange splice shall be al
52L2,2 Seismic"liy COlllpact
le ast equal to 0.5 fI,F,A, (LRFD) or (O .S/l.S) R,F,A,
When required by these Provisions. members of the SLHS
(AS D), as ap propriatc, whe re U)'l~. is the expected yield stress of the column material and AI is the nange area of th e smaller column connected .
must hnvc flanges continuously cOllllected (0 the web or webs and the width-thickness nHies or its compression clements shall nol exceed the limiting width-t hi ckness nHios , APS, from Provisions Table 52! -! .
521.3 Column Strength When PI< I¢ Pn (LRFD ) > 0.4 or D,P,;P,. (AS D) > 0.4, as ilppropriare. wi thout consideration of the
where ~,.
= 0.90 (LRFD)
Q,. = 1.67 (ASD)
= required axial strength of a column using ASD Load co mbinat ions, N :::: nominal axial st rength of a column, N :::: required ax ial st rength of a colum n usi ng LRFD load combi nations, N
P" P" P"
The following requirement shall be mel: I.
The req uired axial co mpressi ve and ten sile strength, considered in the absence of any applied moment. shall be determined lIsing the load combinations stipu lated by the NSCP code including the amplified seismic load
2.
The required axial compressive and tensile stren gt h shall not exceed either of th e following:
n.
The
maximulll load transferred to the column conside rin g LlRy (LRFD) or ( 1.1 11 .5) Ry (ASD), as appropriate. times the nomi nal stl'engths of the connecting benm or brace clements of lhe building.
b.
The limit as determined from the resistance of the fo und ation (0 overturning uplift
Beveled transitions arc not required when chan ges in thickness and wid th of Ilangcs and webs occur in column splices where flJP groove welded joints are used. Column web splices shall be either bolted or welded, or
welded (0 one column and bolted to the other. In moment frames using bolted splices, plates or channel s shall be used on both sides of the column web. The centerline of column splices made wi th fillet welds or pa ni a l ~jojJl{-penctraiion groove welds shall be located 1.2 III or more ,",way from the beam-to column co nn ections. When the column clear height between beam-ta-column connections is less than 2.4 Ill , splices shall be at half the clear height.
521,4,2 Columns Not Part of lhe Seismic Load Resisting System
Splices of col um ns that are not a pan of the SLRS shall satisfy the following: I.
Splices shall be located 1.2
III
or morc away from the
beam -Io column conn ections. When the column clear
hei gh t betwee n bea m-to column connecti ons is tess than 2.4 Ill , splices shall be (11 half the clear height. 2. Th". required she
Mpc IH (LRFD) or Mpc 11.5H (ASD), as appropriate, where Mpc is the lesser nomin al plasti c fle xu ral strcngth of (he colu mn sections for the di recti on ill question , and H is the story height.
1h
National Siructural Code o r the Philippines 6 Edition Volume 1
s- 1GO
CHAPTEH 5 . SI(;.'el and Melnls
521.5 Colulllll Bases
where
The required stre ngth of colum n bases shall be ca!culillcd in ;u.:con.hlllcc with Sectiolls 52 J .5.1.52 I .5.2.
IJ
The available st ren glh of concrete clement s at the column b
b.
steel, shall be in accordance with ACJ 3- 18, Appendix D.
,. .
=:::
height of swry, which may be taken as the distance. helwccilthc centcrline or 1100r framing ill car.:ll of the levels above and below, or the distillH.:e helween the top uf noor slabs OIl cach or the levels above and below. mill
The shcilr cakulHtcd using the IO<1d combina ti ons or the N~;c: r code, including the amplified seismic load.
Secti on 52 1.5.2. Requ ired Flexural Strength . The required flexura! strength of column bases, including their att ac hment 10 the foundation, shall be the summati on of th e. required strengt hs or the stcel c1cmcnts thai arc conncc ted to lhe column base as rollows: I.
For diagona l bracing. the requi red nexural strength shall bc a\ lenst equal 10 the required strength or bracing co nncctio ns for the SLR S.
2.
for columns, the required flexural strength Shill! be ,H lea!;t equal 10 the lesser of the (ollowing:
a.
1. 1 R,F,Z (LRfD) or ( 1.111.5) Ii,F,Z (ASD). os appropriate, of the column or
b.
the moment calcu lated using the 1000Id com binations o f' the NSCP code. includ ing the amplifIed seismic load.
Exceplion: The special requiremel1l5 in ACI 3 JB, Apptmdi:t' D. for "regions of moderme or high seismic risk. orfor sirucllfre.r assigned 10 illlermedime or high seismic per/ormllllce or design categories" lI eed
//0/
lu.' applied.
521.5.1 Required Axial Strength The required ax ial strength of column bases, including their altachmcnl 10 the foundation, shall be the summation of Ihe venica l components of the requi red strength s of the steel eleinents that nre connec ted to the column basco 521.5.2 Requi red Shear Strength The required shear strength of colu mn bases, including their attachments to the foundations . shall be the sll lllmmion of the horizontal component of the requ ired st rengths of the steel elements that arc connected to the columJl base as follows: I.
For diagonal bracing, the ho rizontal component shall be determined from the required strength of bracing connections for the seismic load resisting sys tem (S LRS)
2.
For columns, the horizolllal component shall be at least equal to the lesser of Ihe fo ll owing:
a.
2R.,. F). Zx IH (LRFD) OJ' (211.5) Ii,. F, Z, If! (ASD). as appropriate. of th e columJl ..
521.6 H-Piles 521.6.1 Design of H·Piles Design of H-piJes shall compl y wi th the provisions or the Specification regarding design of members subjected to combined loads. H -p iles shall meet the requirements of Sectioll 521.2 .2.
521.6.2 B.Hered H-Piles Ir baltered (sloped) and vertical piles arc used in a pile group, the v.crtica l piles shall be designed to support the combined effects of the dead and live loads without Ihe participati on of the baltered piles. 521.6.3 Tension in H-Pile Tension in each pile shall be transferred 10 the pile cap by mechanical me'lIls slI ch as shea r keys. rcin forcing bars or studs welded (0 (h e embedd ed porti on o/' the pik . Dircc!l y below the botlom of the pile ca p, e:lch pi le shall he free of all:lchmCllls .lnd we lds for a length al least equal to the depth of the pile cross section.
Association of Structural Engineers of the Philippines
CHA P 1E: '~ !>
SECTION 522 SPECIAL MOMENT FRAMES (SMF)
Bcam-to-columll cOllllecti ons used in the seismi c lo,\d
resisting system (SLRS) shall satisfy the follo wing Ihrce requirements: I.
The connec tion shall be capable of sust:.umng an iu(crstory drift angie of at least 0.04 radia ns.
2.
The Illci.lsurcd flexural rcs islancc of the COIHlccl ion,
determined <1\ Ihe column face, shall eq ual al least O.80Mp of th e connected beam at an inlcrslOry drift angle 0[0.04 radians . 3.
The required shear strength of the cOllnecti on shall be determined usin g th e followi ng quantit y for the earthquake load efrect E: £= 211.111., M,,) 1 L.,
(1:'1. 522- 1)
where
R., Mp L "
:::: ratio of the expec ted yield stress to the speci lied minimum yield stress, F, = nominal plastic fl exural strength, N - Illlll :::: distan ce between plastic hinge locat ions, 111111
When E as defined in (Eq. 522-1 ) is used in ASD load combinatio ns that arc addi ti ve with other transient loads and that arc based on SEIIASCE 7, the 0.75 co mbination factor for transient loads shall not be applied to ·E. Co nn ec tions that acco mmodate the required illicrstory drift a ngle within the co nnection clements and provide the measured flexural resis tance and shear strengths specified above are pe rm itted. In addition to s
Beam-la-column con nections used in the SLRS shall satisfy th e requirements of Section 522.2 by one o f th e following:
J.
Use of SMF connecti ons designed in accordance with ANSIIA ISC 358.
~-
16 1
Usc of a connecti on prcqualified acr ordam.:c wit h Section B- 1.
J.
Provision or qualifyi ng cytl ic lcst result s in
iL
Tes ts reported ill th e research literature or docull1ented tes ts performed for other projects that represe nt the project conditions. Ivi th in the limits specified in Section 1l-4.
b.
Tests that arc conducted specifically for the project m}d are represcntati ve of project member sizes, matcri
522.2 Bc;.un-to·ColuJUI1 Connections 522.2. 1 Requiremen ts
<'I nd Metal
2.
522. 1 Seo!,c Spec ial moment frallles (S MF) arc cxpe(.~ lcd 10 withstand significant inelastic deformations when subj ec ted to the forces resulting from th e 1I10[ions of the design ca nhquak~. SMF shall satisfy the require ments in this Section. .
S l (~c l
for SMF in
522.2.3 Welds
Unless otherwise designated by ANSIIA ISC 358, or otherwise determined in a connection preq uali fi cati on in thest , )P.JoYisio~..c "Wbere these Prqyisio~ iri\licate that a p,artlc.,.lar· , ,,,,~)d ~ i~ , aesigtia)cd demaiid t:ritical. but the more specific stll;nilaro.'!>r test does n
The regi on at each end of the beam subject to inelasti c straining shall be design ated as a protected zone, (l1ld shall thee t the requirements of Section 520.4. The extent of the protected zo ne shall be as designated in ANSIIAI SC 358, or as otherwi se determined in a connection prequalification in accordnnce with Section B-1 , OJ' as detennjncd in a program of qualification testing in accorda nce wi th Section 13-4.
User Note: The plastic :hinging zones at the ends of SMF beams shoul d be treated as' protected zones. The plastiC hinging zones should be established as part of a prequalification or qu'a1ificatioQ"prograni for:the ,cpnneetion. per ,...s.<;clJ~P' · 05~2,,2,2. " W.,1 ,gen:~raI, , fOf " , unrein(orcOd
cOli~~C:\i.o~s; ih.~ ~r9t,*t~ 10~~ Wiil :~Xl~M :frOtli t~,~ 'f~c~ .\\f
·ht!§Wf,u~~ iii t: :W,bhe ~W'- 0fiW~,~~~~l ;~~ptl!bey
National Structural Code of the Philippin es 6
1h
. :" ':
Edition Vol ume 1
'
~)--H)?
CHAPTEH~)
Steel and Metals
522.3 Panel Zone of Beam-to-Column Connections
522.4.1 Width-Thickness Limitations Beam and column members shal! meet the requircmcnts (:.;' Section 521.2.2, unless otherwise qualified by tests.
(Beam Web Parallel to Column Web)
522.3.1. Shear Strength The required thickness of the panel ",one shall be determincd in accordance with the method used in proportioning the pancl zone of the tested or prequalificd COll'lCction. As a minimum, the required shear strength of the ~~:illel zone shall be determined from the summation of the moment~; at the column faces as determined by projecting the expected moments at the plastic hinge points to the column faces.
The design shear strength shall be f{JvR" and the allowable shear strength shall be R/QI' where 9'1'
= 1.0 (LRFD)
Q, = 1.50 (AS D)
and the nominal shear strength, R,., according to the limit state of shear yielding, is determined as specified in Specification Section 510.10,6. 522.3.2 Panel Zone Thickness The individual thicknesses, t, of column webs and doubler plates, if used, shall conform to the following requirement: (Eq. 522-2)
522.4.2 Beam Flanges Abrupt changes in beam flange area arc not permitted ii, plastic hinge regions. The drilling of nange holes or trimming of beam flange width is permitted if tc.'·;[~ng or qualification demonstrates that the resulting conngunlli(\,~ can develop stable plastic hinges. The configuration shaH [;,.;: consistent with a prequalified connection designated ;;. ANSIIAISC 358, or as otherwise determined in connection prequalification in accordance with Section B· : or in a program of qualification testing in accordance with Section B-4.
522.5 Continuity Plates Continuity plates shall be consistent with the prequalificd connection designated in ANSIJAISC 358, or as otherwise determined in a connection prequalification in accordanc· with Section B- J, or as determined in 11 program (;1 qualification testing in accordance with Section £3-4.
522.6 Column-Beam Moment Ratio The following relationship shall be satisfied at beanHo-· column connections:
where
L: [ L:
=thickness of column web or doubler plate, mIll. dz Wz
= panel zone depth between continuity plates,
111m.
= panel zone width between column flanges, mm.
Alternatively, when local buckling of the column web and doubler plate is prevented by using plug welds joining them, the total panel zone thickness shall satisfy (Eg. 522-2).
522.3.3 Panel Zone Doubler Plates
Doubler plates shall be welded to the column flanges using either a complete joint-penetration groove-welded or filletwelded joint that develops the available shear strength of the full doubler plate thickness. When doubler plates are placed against the column web, they shall be w61ded across
the top and bottom edges to develop the propol1ion of the total force that is transmitted to the doubler plate. When doubler plates are placed away from the column web, they shall be placed symmetrically in pairs and welded to continuity plates to develop the proportion of the total force that is transmitted to the doubler plate. 522.4 Beam and Column Limitations The requirements of Section 52 I shall be satisfied, in addition to the following.
M
p,.»
1.0
(10'1.522-3)
M p"
where = the sum of the moments in the column above and below the joint at the intcrsection of the beam and column centerlines. IM"e is determincd by summing the projections of the nominal flexural strengths of the columns (including haunches where used) above and below the joint to the beam centerline with a reduction for the axial force in the column. It is permitted to lake EM,,,. =ElJ F". -1',,, IA,) (LRFD) or I2AIF,/i.5) Po, lAg)] (ASD), as appropriate. When the centerlines of opposing beams in.the same joint do not coincide, the mid-line between centerlincs shall be used. = the sum of the moments in the beams at the intersection of the beam and column centerlines. EM,,/! is determined by summing the projections of the expected flcxural strengths of the beams al the plastic hinge locations to the column centerline. It is permitted to take EM"b=(l.iR,E'~bZ,,+ M",.) (LRFD) or E[(l. 1I1.5)R y F)bZ" + M,,,.] (ASD), as appropriate. Alternatively, it is pennitled to determine EMp/J consistent with a prequalified connection design as designated in ANSlIAISC
Association of Structural Engineers of the Philippines
M",.
P,,,
P,,, Zh Z,. ZIIIIS
358, or as otherwise determined in a con nection prcqlwlific(llioll in ilccordancc with Seclion B-1 , or illli program of qualific,Hion testing in accordance with Section B-4. When connccti ons with reduced bc;nH sections lIrc used, it is permitted 10 lake l'Mph=I.{ 1.IRJF,h ZIIIIS+M,,,.)( LRF))) or .1.1r 1.1I1.5)R,F,b ZRlIS + M",. ) (AS))), as "pprapriale. . 7' gross area of column , Illm 2 ;: spcdficd minimulll yield SIF"~;S of colu/1lll, MPa ;;: the add itional moment duc [0 shear amplification from the location of (he plilslic hinge lO the COIUIllIl cCIHcrline. based on ASD load combin3lions. N-mm. :::: the additional moment due to shear amplification frolllthe location of Ihe plastic hinge to the column centerline, based on LRFD load combinations, N-mm. = required compressive strength using ASD load combinations, (a positive !lumber) N = required compressive strength using LRr=D load combinations . (<1 po!)itivc number) N ::: plastic section modulus orille beam, I111ll3 ::: plasti c section modulus of the column, 111m3 = minimum plastic section modulus at the redu ced bealll section, IlHll ~.
= PUC> required comfJr('ssil'(~ .l'treIlKth, usilllt LR Ff) load combillllliolls, N.
P" .
For design (l('(:ordillg to Specijicatioll Sl'('lioll 502.3.4 (ASf)),
P, Pro'
2.
= FI'•.A,,//.5. N ;;:; P:., .• required (·ompl'('s.,·i\·(· srrength. usillg A.S·t) load c()l1Ibill(l(ioIlS, N Columns ill any story that has a ralia (~(~jv(lilabl(' .die'ar Strength to I'l'quired sheor strength Ihal is 50 perci!l1f grea ter Ihall Ihe !ilory above.
522.7 Lateral Bracing at Beam-to-Column Co nn ection s
522.7.1 Braced Connections Colum11 f1ange.~ at beam-to-column connections requirc lateral bracing only at the level of the top Ollngcs of th e beams, when the webs of the beams and column are coplanaI'. and a colu mn is shown to remain clast ic outside of the panel lOne. h shall be permitted 10 asstll.ne that thc colulllil remains clastic when the ratio CaJculnlcu using (Eq . 522-3) is greater than 2.0. When a column c(lnnot be shown to re main elastic outside of the panelzonc, the following requiremcnts shall apply:
Etception: This requirement does not apply two conditions is satisfiul: J.
if either
of the following
Columlls with Pn' < O.3Pc for all foad combinatiolls other than dIOse determined using the amplified seismic load ,har sariJf1' either of 'he following:
n_
CO/UII1I1S used in a one-story building or the top story oJ (l multistory building.
b_
Columns when': (J) Ilw sum oj tlie available shear sfrenRlhs of all exempted colllml1.~· ill (he slory is It!SS than 20 percellT of (he sum of til(! CIvailable shear Sirengths of al/ mOll/ellf Jrame columns in Ihe story acting ill the same direction; and (2) the su m of the Gl'al/able shear slrellgt!Jj' of all exempu'd COIIlIllIlS all each moment frame column line IvirhilJ fhat .
IVhere
For design according to 5j)ecijicmion Sectioll 502.3.3
(LRFD),
Thc column flanges shall be I[tlerally braced at the levels of both the top and bottom beam nanges. Lateral bracin g shall be either direct or indi rect. User Note: Direct lateral suppolt (bracing) of the column f1iu1lle ·is 'iichieved through iise of braces or other members, deck' arid 's!iih'; attached ·ta 'the column flange at or near the desired· br4ci ng pOint ·ta resist lateral budding. Indirect iate\iU suppon refers to braCing that is achieved tllfough· the stiffness·:of·members and connections that are noL directly attached Lo the column ·f1anges, but rather aet tlu"Ough ·tllC column web or stiffener plates.
I.
Each column-flange lateral brace shall be designed for a required strength th at is eq ual to 2 percent of the available beam flange strength 1·~\'bflf4 (LRFD) or /;:"bj thj 11 .5 (AS))), as appro prime.
522.7.2 Unbraccd CO lln ect ion s A column containing a beflln-to-column cOllllectio n with no latcral bracing tran sverse to the seismic frame at the connection shall be designed lIsing the distance between adjacent lateral braces as the column height for buckling transverse to the seis mi c frame and shall conform to Specification 508, except that: 1. Thc required column strength shall be determined from the appropriate load combinations in the NSCP code,
NaJional S iruciural Code 01 Ihe Plli1ippines 6'" Edition Volume 1
except that 1:: shall be Ii.lkCIi CIS the Jesse!" of: ;1.
The ampJified scis mit: JOild .
11 .
125 percent of tile frame avai lable strength based upon either the heam av,ji lahlc /lcxuf,d strength or pilllel zo ne aVili JahJc sht.'ar strength.
2.
The slenderness l.Jr for lhe column sh.tlln OI cx(;(:cd 60.
3.
The t.:ol ullln rC{lujr~d nexuret' strength lransvc.s' 10 lhe seismic frame shall include that JIlOlllenl t.:
II
I
I r
!
10
nu' rCf(lIirc' c/ ....'reI1XIfI oj Iflt' ("01U11111 spliC<1 comic/nil1k (lpprofJriu/(1 S/n'.H cOIweli/ntiiOIl [cu.:lOrs or ji'u ctun: lIIl'dlllllics slre.\·.\" illl(,JI.'.ily jllC/or.r lI('ed I/ot t'xn'cc/ flult
de/ermilled by illdo.Hie tl/w{y.I'l'.I".
the resulting column flange displaccmcili.
522.8 Latent. Bracing of Hc,alJls
DOlh fla nges of beams shall be I.uerall y braced. with ,I maximum spacing o f LI/ ;::; O.086ryElF\.. Braces sha ll mee t the provis ions of Equations A-I -7 and A-1-8 of Appendix A-I.6 of the Specification. where M, = M. = R,ZP, (LR FD) or M , = M" = R,ZF,.11.5 (ASD). as appropriate. of the beam ;lIld Cd = 1.0. . III 'J(ldi ti OI1. lateral braces shall be pl aced ncar cOllcen trated
forces, changes in cross .. scction , and o th er locati ons where anal ysis indicates Ihal a plastic hinge wi ll fOf m during inelastic defo rmations of the SMF. The placement of lateral bracing shall be consistent with that documented for a prcqualificd connection designmcd in ANSUAISC 358. or as otherwise determined in a con necti on prcqualificalion in accordance wit h Section B·I , or in a program of qualificmion testing in accordance wit h Section 8 -4.
The required st rength of imcral bracing provided adjacent to plastic hinges shali be p. = 0.06 M. Iii" (LRFD) or p. = O.06M 1/1" (ASD). as appropriate, where II" is the distance between flange centroids; and the req uired stiffness shall Illeet the provi sion s of Equation A-J-8 of Appendix A-1.6 Q
of the Speci fi cat ion. 522.9 Co lumn S pli ces Column splices shall comply wi th the req uirements of Secti on 521.4.1. Where groove we lds are llsed 10 make the
spli ce, th ey shall be complete-joinl-penetration groove we lds that meet the req uirements of Sect ion 520.3.2. Weld labs shall be removed . When column split.:es are not I1lmlc with groove welds. Ihey shall have a required flexural strenglh thaI is at least equal to RyI~\2.1 (LI~FD) or RrF..\Z.1 / 1.5 (ASD). as appropriate. of the smalicr columl1. 11,e required shear strength o f colum n web splices sllil ll .be ill
least equa l to EM, ... 111 (LRFI) ) or EM,,,. 1/.5H (ASD). as appropriate. where LMpc is the sum of tile nominal plastic flexural strengths of the columns above and below the spli ce. Exception:
Association of Structural Engineers of the Philippines
SECTION 523 INTERMEDIATE MQMENT FRAMES (IMF)
designate welds as demand critical that are not identified as
such by these Provisions. 523.2.4 l)rotected Zone The region at cHeh end or Ille beam subjcl"t 10 inelastic
523.1 Scop" IntcJ'fncdial c
1l10mCll! frames (lMF) arc expected !o withSland limited incJasli c deformations in thei r members and co nnecti ons when suhjectcdlo the forces resulti ng from the motions of the design earthquake. IMF ~; hal! meet the
requiremcn ls ill thi s Section.
523.2 Beam· to-Column Connections 523.2.1 Requiremenfs Bcmn·lO-columl1 COIHlcclions used in the se ismic lo'ld rcsisling syslcm (SLRS) shall sati s fy the requ irements of
Section 522.2. with the following exceptions: I.
2.
The required inlcrslory drift angle shall be a minimu lll of OJJ2 radian.
The required strength in shear shall be dClcrmined as specified in Section 522.2 . 1, except thaI n lesser valut' of V" or V(I' as appropriate, is permitted if justified by analys is. The requi red shear stre ngth need not exceed the s hear resulting from the appli cat ion o f appropriate lood combinations in the NSCP code using the amplified seismic load.
straini ng shell I be Irt!ntcd itS a prot ected zone. ;l nd ~ ha ll meet the requiremcnts or Section 520.4. The ex tent oj" the prot c<.: tcd zone shaH be as dcsig nat ed in AN SIIA IS C 15 8, or as otherwise detcrmined in it <.:onnctt il)n prclj ualifi cill ion in accordance with Scction 8 - 1. or as detcrmined in a program o f qu.lliHciltion tcsting in a<.:cordar.cc wi th Section B-4.
User Note: The plastic hinging zones at the ends of IMF b~aJ11s should be treated as ' pioteCted 'wnes. The plastic hinging zo'nes should be established as part of a prequalification or qualificiuion program for the connection. In general, for unreinforced cOnriec·tions, the ·protected zone will extend from the face of the column ' to one half of the beam depth beyond the plastic hinge point. 523.3 Panel Zone of llea m·to-Column Connections (lJen," Web ParaUel to Column Web) No additional requircmellts beyond the Specification.
523.4 Bcam and Column Limitations. The requircmcnts of Section 521.1 shall be sati sfi ed, in addi[ion to the foll owing. 523.4.1 Widlh- Thickness Limitations
523.2.2 Conformancc Dcmonstration Conformance demonstration s hall be as desc ribed in Section 522.2.2 to satisfy th e requirements of Section 523.2. 1 for IMF, exeepl that a connecti on prcqualificd for IMF in accordance with ANSIIAISC 358, or liS otherwise determined in a connection prequalilication in accordance with Section B· l. or as delermined in <1 program of qualification testing ill accordance with Section 0-4.
523.2.3 Welds Unless otherwise designated by ANSIiAISC 358. or otherwi se determined in a connection prequalification in ::lccordilnce with Section B·l, or as determined ill a· program of qualification testing in accordance with Section B-4, comple te joint · penctratio ll groove welds of beam nanges.
shear plates, and beam webs 10 columns shall be demand cri tical we lds
described in Section 520.3.2.
User Note: For the designation of de mand critical welds, standards such as ANSII AISC 358 and tests addressing specific connections and joints should be used in Jieu of tJ)e more g~ner.al. ·. teqns of these Pr~JVisiol.1S. Where these
PrQvis!ons j~d,i.9.a\e tl)at , R ' p;uticular . ",eld i$. ,designated demand critical, b),i.i. the 'l1)0re spe,Wc staI),Q¥d'Or ·te.sl ·does nQt Jilak~ ~l'~~;"l . 4¢sigl),a~6Iidtw: mQr~ ' spefj@· s,tan~,~d or lesLSAQulq go)i~J;Il, .Like\~ise, thesest"!4iu:ds .,~nd.,.i\'~is: may
Beam and column members shall meet the requireme nts of Section 52 1.2 . 1, unl css otherwise qualified by tests . 523.4.2 Beam Flonges Abrupt changes in beam flange arca arc not permitted in plastic hinge rcgions. Drilling of flange holes or trimming o f beam n angc width is permiued if testing ur qualification demonstrates that the resulting configuration can develop stable plastic hinges. The configurati on sha ll be consistent with a prequalified con nec ti on dcsignated in ANSIIAISC 358, or as otherwise determined in a connection prequalification in accordance with Secti on B-1 , or in a program of qualifica ti on tes ling in accordance with Section 1J·4 . 523.5 Continuity Plates Continuity plates shall be provi de d to be consistent with the prcqu alified con nec ti ons design.lle.d in ANSIJA ISC 358. or as otherwise delermined in it con necti on preq u,llificalion in accordance wi th Section 13-1 , o r as deten n in ed in a program of qualificati on testing in accordance with Scction B ~ 4. 523.6 Column·lleam Moment Ratio No additional requirement s beyond th e Specification . Lat eral Bracing at Beam-lo-Colulllll COllllecti ons No
National Struclura l Code of the Philippines 6:1; Edition Volum e 1
addi tional rcquirclllcllts beyond th ~ Specificl.ltion. Latcml Bracing of Beams BOIh flanges sh,lIl be lat crilJly braccd dirc<.:lly Of indin!<.:ll y. The LJnbril ccd kllglh betwecn latcral hr
1.6 of the Specificmion. where M,= M,,=R,ZF, (LRFD ) or M. =M,=R,ZF,.II.5 (ASD). '" appropriate . 01" Ihe bealll. and C" = 1.0. JIl addi lion, lateral braces shall qc placed nc.u· concentrS-section and other locations when: analysis ind icates tbm a plasti c hinge will fC)J'Jl1 during
inelastic deformati ons of the IM F. Where the design is based upon assemblies tested in accord:lllce wit h Secti on B4, the placement of lateral bracing for the beams shall be consistent with Ihat used in the tests or as required for prequalification in Section 8-1. The required stren gth of lateral bracing provided adjacent to plaslic hinges shall be P.=O.06 M" Ih. (LRFD) or p. = O.06M. I .. (ASD). as approprime. where. ho = distance hetween nange centroids; and the required stirrness shall meet the provisions of Equation A-I-8 of Appendix A- 1.6 o f the Specificati on. Column Splices Colllmn splices shalt comply will! the requirements of Sect ion 521.4.!. Where groove welcls arc used (0 make the splice, they shall be complete-jointpenetration groove welds that mee! the requirements of Section 520.3.2.
...
'
SECTION 524
.
..
·;,..1 ··.'iii
Q~WAAY.:M()MENT F~;i,i;iJ~1~\.\ (OMF)
.
" ~t::iri
524.1 S,·opc Onlill;.lrY mOlllcnt frallles (OMF) nrc expected 10 withstand minim al inelastic (/eronumions in their members and co nnections when subjec ted to the forces resulting from the motions of the design c.lrthquakc. OMF shall meet the rcqlJirClllcnts of thi s Section. Connections in conformance with SCClions 522.2.2 and 522.5 or Sections 523.2.2 and 523.5 shalt be permitted for usc in OMF without mceting the requirements of Secti ons 524 .2. 1,524.2. 1. and 524.5.
,!ss[J'fJ!1!: j.'Ilil,~ UI~seef?visi.Qn". for9MF. )r,~~;P~~!y deY.el?,~ t?r.¥,se_ll'!tt~ wtde fiarge sb~peS •. With JU~~~~J ,
they may ruso be ~liPtt<;\l to pthet s~~pes sucfi . ~. clianne1s' buiit-up sections, and hollow s truei~ral sections (HSS): . c·>'.
524 .2 Bcam-to-ColuIl1l1 Connections 13eanHo·column cOllnections shall be made wilh welds andlor hi gh-s trength bolts. Conncctions are permitted to be fully restrain cd (FR) or partially restrained (PR) momenl connect ions as follows. 524.2. Requirem ents for FR Moment Co nnections FR moment connections that are part of the seismic load resisting system (SLRS) shall be designed for a required nexu,.al strength that is equal to 1.1 Ry Mp (LRFD) or (1.111.5) R, Mp (AS D). as appropriate. of the beam or girder. or tile maximulll moment that ca n be developed by the sys tem. whichever is less.
FR cOllllections shall meet the rollowing requ irements. I.
·Where Rteel backing is used in connections with co mplete-joint-penetrati on (CJP) beam flange groove welds, steel backing and tabs shall be removed, except that top-flange backing attached to the column by a continuous fillet weld on the edge below the CJP groove weld need not be removed. Removal of steel hacking and tabs shall be as follows: FOllowing the removal of backing. the root pass shall be back gouged to sound weld metal and back welded
wil h a reinforci ng fill et. The reinforcing fi llet shall ha ve a minimullllcg size or 8 mm . h.
Weld tab removal shall extend Lo within 3 111111 of the base metal surface, except at continuity plales where removal to within 6 mm of Ole plate edge is acceptable. Edges of Ihe weld tab shall be finished to a surface roughness value of 13 ~111 or betler. Grinding to a flush conditi on is not required. Gouges and notches are not permitted. The transitional slope of any area where gouges and notches have been removed shall nof
Association of S tructural Engineers of tile Philippines
excecd 1:5. Malcri4l1 rem()vcd by grinding Ihal cxtCIUJ.s morc than 2 111111 below th e surrace of the base Illct.1l sha ll be lillcd with we".! mctal. The contour of Ihc weld •11 the ends shall providL'" II SllloOlh transition. free of" notc hes illld sharp corners.
2.
3.
.
'
Where we ld access holes arc prov ided. the), s!1iI11 be as shown in Fi gurr 524 - 1. The we ld access hol e shall have il surfill'c roughness v:llue not to exceed 13 'lin, and shall he free of nOlch.es and gouges. Notches ilne! go uges shall be repaired as required by the engineer-of· record . Weld access holes arc prohibile.d in the beam web adjace nt 10 the end-plate in boiled mOIllC IlI end· plate con necti ons. The required st rength of double-sided panial-jointpenet ration groove we lds and double-s ided fillet welds that resi st tensi le forces in COllllcctions shall be I.IJlJ ' ,A, (LRFD) or ( 1.1 / 1.5) JI,F,A , (AS D), as appropria te, of th e connecled element or poln. Singlesided panial-joinl'penctrm ioll groove welds and !
~, ...."
) '-f'''''' ~ I> '"
•• , \', '"
nh''''
''I'
".>1....
'111 ,,'m' "'''','''''''' "oJ"" ' rl.. , ...... fo.."I.....
~ .1 '.,' 1 II: '" "t II."",.
''''n~'
,1>." .... . ""~' I,' ",
II,
,b.' ~ ..". " h ..),· ,u' ,.. ,) .... 11:\"...·
....,b.~.".·,-d,;!o ·
For PI? moment con neelions, (he required shea r st rength, V" or II", as appropri ll te. or th c cOllncc tion shall bc determined using th e following qua nti ty for tile eart hquake load effect £:
E; 211 .1".,. Mel / L"
,,,,n,,...
l:>l,·'~n • •• '1o~1l .~ ~ :"'·~"",I ....· ~. 'I...·
fo rces ill the con necti ons.
4.
I U... ~I .., ""f"'~II, .. ....1.....,,-.1 , .... ....... ~ ..I : 1.;00,." "i .., ... ~; ... I l l _... lrl~. 1/:(.... ,.- '''' .... , '.~ ~; r.; 'd fl O n,,,~,n lit
(Eq . 524 · 1)
Where (his £ is llsed in AS D load combi nations Ihat arc additive witli other transi ent loads ilnd that are based o n SEIIASCE 7, the 0.75 combination factor for transient loads shall not be applied to E. Altertlillivcly, 11 Icsser valuc of V" or \1" is permitted if justifi ed by anal ysis. The required shear strength need not exceed the shea r resu lt ing from Ihe app li cati on of appropriat e load combinations in the NSCP code lIsing the a mplifi ed seismk load .
Fig. 524·1 Weld· Access hole detail ( rro lll FEMA 350, "Recommended Seismic Des ign Criteria for New Steel Moment-Frame Buildings") 524.2.2 Requiremenfs ror PR Moment Con llections
PR momen t connections are permitted when the following requiremen ts are mel: I.
Such connections shall be designed for the requ ired strength as speci fied in Section 524.2. 1above.
2.
The nomin al flcxuml strength of the connection, M". shall be no less th an 50 percent of M il of the con nected beam or column, whichever is less.
3.
The stiffness and strength of the PR moment connec tions shall be considered in the design, includin g the effect on overall frame stability.
4.
For PR moment connecti ons, VII or Va, as appropriate, shall be determined from the load combination above plus the shear resulting from thc maximum end mOJl'lcnt 1h;]1 the connection is capablc of res isting.
524,2.3 Welds Comple te-joill t-penetrat ion groove wel ds of beam l1anges. shear plates, and be.1111 webs to columns shall he demand critical welds as described in Section 520.J .2. 524.3 Panel Zone of Beam·to·Column Connecti ons (Beam Web Parallel To Column Web)
No addi ti onal req uirement s be yo nd the Specification .
th
Na tional Struclura! Code of lhe Philippines 6 Edition Volume 1
524.4 Beam and Co lullllI Limitations Nu requirements hl!yond
S~ction
521 . 1.
524.9 Column Splices Columll splices shall comply with the rcquircmcnls or Sectioll 521.4.1.
524.5 Continuity Platl's
When FR moment t'ollncctiollS arc madc by me,tIls uf welds of beam l1angcs Or bC
td< 0.54
Jb {'/I/ F,,"{F,(,
or when 1"
< bf l6
Where cOnlinu it y plates arc reCjuired, th e thickncss of the plates shall be determined :JS fo ll ows:
J.
For one·sidcd conncclions. continuity plate thickness shilll be at least one half of the thi ckness of the beam
flange. 2.
For two·sided connections thc continuity plates shall be
at least equal in thi ckness to the thicker of the beam
flanges. The welded joints of the continuity plates to the columll nanges shall be made with e ither comp!ctc·joint·penctration groove welds, Iwo·sided partial-joim penetration groove welds combined w ith reinforcing fillet welds, or two-sided fillet weld s. The requi red strength of these j oint s shall not be less than the avai lable strength of the contact area o f the plate with the column flange. The required strength of the wel ded joints of the continuity pl atcs 10 the column web shall be the least o f the foll owing: a.
The sum of the available strengths at the connection s of the contin uit y plate to the column flange s. The avai lable shear s trength of the contact area of the plate with the column web.
b.
The weld avai lable strength that develops the avai lable shear strength of the column panel zone.
c.
The actual force transmitted by the sti ffener.
524.6 Cohunn·Bcam Moment natio No additional requirements beyond th e specificati on 524.7 Lateral Bracing at lleam-lo·Column Connections No additional requirements beyond the Spccifi ca tio n.
524.8 Laleral Bracing of Beams No additional requirement s beyond the Specifica ti on.
Associa tion of Structural Engineers of the Philippines
SECTION 525 . _ . . . . . SPECIALTRUSSM(j'MENl'FMMES (STMF) < :'. .. 525. I Scope Special tru ss mo ment frames (STMF) arc expected 10 withs tilnd significant inelasti c deformation within a speciall y designed segment of the tru ss when subjected 10 the forces from the Illotion~ of the desi gn earthquake. STMF shall be limited to span lengths betwee n colu mns not to exceed 20 III and ovcm1J depth not to exceed 1.8 m. The columns and truss seg ments o utside of the speci al segments shall be designed 10 remain elasti c under the forces that call be generatcd by the full y yieJded and strain-hardened special segmcnl. STMP shall meet the requirements in th is Section. 525.2 Special Segmenl
Eac h horizontal tru ss lhal is pall of the seismic load resisting system (S LRS) shall have a special segment thm is located between the quartef point s of the span of the tfUSS. The length OJ the special segment shall be between 0 .1 am.l 0.5 times the truss span length . The lengtlHo-deplh ratio OJ any panel in rhe special segment shall ne ither exceed 1.5 no r be less Ihan 0.67 . Panels within a special segment sha ll e it her be all Vi ercndeel panels or all X-braced panels; neither a combination thereof nor the use of other truss diagonal configurations is permitted. Where diagonal rnember:s afC used in the special segment , Ihey shall be arranged in an X paHcm separated by vertical mem bers. Such diagonal members shall be interconnected al poin ts where th ey cross. The interconnection shall have il required strength equal to 0.25 times the nominal tensile stren gth of the diagonal member. Bolted connections shall not be used for web members within th e special segment. Diagonal web members within the special segment shall be made of nat bars of identical sections. Splicing of chord members is not permitted within Lhe special segment , nor within one~halJ the panel lenglh from th e ends of th e special segment. The required axi al strength of lhe diagonal web members ill the special segment due to d ead and li ve loads wi thin the special segment shall not exceed O.03(-~A g (LRFD) or (0.03/1.5) F,A, (ASD), as appropriate.
The speci al seg ment shall be a protected i:'.one meeling th e requi rements of Section 520.4. 525.3 Strenglh of Special Segmenl Members
dlOnl mrmhc r!\ through ncxllr~ . and thc shcar strcngt h correspo nd ing to the availab!e lCIl!'iilc strengt h and 0.3 limes tht: avai bhJc co mpressive stre ngth of the diagomil mcmbers. when they arc used. The top and bottom chord members in th e spccial segmcnt shal! be mad e of identical scctions and shall provide at !ea~ 1 25 pen.:C!l1 of the requircd vert ical shear slrcngth . The required axial strength in Ihe chord mcmbers. detCfmined according to the limit St<\tc of tensi le yie lding, shall not exceed 0.45 limes rpP,j (I_Rr-D) or P" / S) (ASD). as appropri"le,
n = J .67 (ASD)
'P = 0.90 (LRFD ) wh ere
T he end connection OJ diagonal web members in the special segment shall have a required stre ngth Ihal is at lea!;1 equal to th e expected yi eld stre ngt h. in tension, of the web
Illember. II, r ,A, (LRFD) or R,F ,A, 1 1.5 (ASD). as
525.4 St rength of Non-Special Segment rs. Members and connecli ons of STMF. except those in the special segmellt specified in Seclion 525 .2. shall have a requ ired strength based on the appropriate load co mbinalions ill the NSCP code . replacing the earthquake load term E with the late ral load s necessary to develop the expected vertical shear strength of the special segment Vne (LRFD) or V" /1.5 (ASD), as appropriale, al mid-I englh , given as: VII" = 3.75R y M",. L~
+O.075 El-(L_'_~_,-) +R ,.(P", + O.3Pnc)sill L(:
a
'
(1'.'1.5 25-1)
where
M,,( El
L LJ Pili P,,,
u
:::: nominal ncxu ral streng th of a chord mcmber or the special segment, N-mm . :::: nex ural elastic segment of a chord member of the special segment. N-mm2 :::: span length of the [russ, mill. :::: length of the special segment, in. (mm) :::: nominal tensile strength of a diagonal member of th e special seg ment, kips (N) :::: nomina! compressive strength of a di agonal me mher of th e special segment. kips (N) :::: anglc of diagonal memoers with the horizon tal
525.5 \Vidth -Thickness Limitati(lils
Chord members and diagonal web members within the special segmclll shall meet the requircments of Section 52 1.2.2.
The available shear strengl h of Ihe special segmenl sl,,11 be calculated as the sum of the available shear strength of the
111
National Structural Code of tile Philippines 6 Edition Volume 1
!i i '/0
CHi\Pl
/:·, n b . Steel anti fI.~(H
525.6 La(crul Bracing The top and bouoJl1 chords of Ill e trusses shall be lall~ral!y br:lccd at the ends of' the special segment. and at irllc rva ls nOI to exceed I", ac('ording 10 Spccific:lli oll Secti on 506, along the entire length of the (russ. The requ ired strengt h of each latcr;,ll brace a[ Ihe ends of ilnd wi lhin the special segment shall be 1'" = 0.06 II, 1'• . (LRFD) or P" = (0.06/ 1.5) II,. P,,, (ASD). as appropriat ~.
whcre = is Ihe nomina! compressive strength of the
-special segment chord mcmber. Lateral braces outside 01' the special segment shall ha ve .1 rc()uired strength of
SEC:rION 526 .. SPEClAL·€ONCENTRlCALLY
BRACED FRAMES'(SCBF) 526.1 Scope
Spcl'i:t1 concen trically braced fmrnes (SeRF) arc Cx.pcctcd
to withstand sig nificant inelastic deformations whe-II subjected (0 !:!lC forces rcsuhi ng from the Illoti ons of Il!:: design earthquake, SeBf- shall meet the requirements in (hi:; Secti on. User Note: Sectioh 527 (OCBF) should be used for tile desig·n of tension-only bracing. 526.2 Members
P" = 0.02 II,. P_. (LR FD) or
526.2. 1 Slenderness
1'" = (0.0211.5) II, I',,, (AS D). as appropriate.
Bracing members shall ha ve
The required brace stiffness shall meet the provisions of Equmion A-I-4 of Appendix A-l.6 of the Specification, where I'r
= I'll =11,.1',.. ( LI~FD ) or
PI" = Pa = II!. Pm· / 1.5 (AS D). as appropriate.
Exception: /Jraas with 4 ,IE If). < Kllr S 200 a re permillfd ill jr(ll1l<'S ill 'which th e (lvoilable Slrel1!; lh of Ihe cO!/im ll is at le(l.r! ('qua/ to !he lI1aximum load [ramferred tv the CO/1I11111 n Il! sideriflg R,. (LRFD) or (//1.5) R\. (ASD). as appropriOi ('.
time.\' 'he ' 1I0mil/(// slrenglli:) oj fhe cOllnecting brace l'/twen ls of the building. Column forces need IIOT excp(!/! those determined by illelaSTic analysis. 1/01' ril e maximwa load effects that CllII be del'e/oped by tire system.
526.2.2 Required Strengt h Where the effective net area of bracing members is less than [he gross area, th e required tensile strength of the brau : based upon the limit state of frac tu re in the nct section shall be greater than the lesser of the following: I.
The expected yield strength , in tension, of the bl'
2. The maximulllload effect, indica ted by analysis th:1l can be lnlllsferrcd to the brace by (he system.
USCI' Note: This provision applies to bracing memh(,Ts where the section is reduced. A typical case is a slotlcd l i~:, .. brace at the gusset plate cOll nection.
526.2.3 Latera( Force Distributi on A long any line of bracing. braces shall be depl")'· : altcrnate dircctions such that, for either di rectio n I;] : ."., parallcl to the bracing, alleast 30 percent ~ut no more li,;:i ~
Association of Structural Engineers of the Philippines
CH/I.[)]"r:n~}
70 percent of the total horijl,ontal force along that line is resisted by braces in tension, unless the available strength of each brace in compression is larger than the required strength resulting from the application of the appropriate load combinations stipulated by the NSCP code including the amplified seismic load. For the purposes of this provision, a line of bracing is defincd as a single line or parallel lines with a plan ofl<;e( of 10 percent or less of the building dimension per pendicular to the line of bracing.
526.2.4 Width-Thickness Limitations
Sleel and Ivlelai
~)·1'l1
526.3.2 Ucquired Flcxural Strength The required flexural strcngth of bracing connections shall be equal to 1.111, Mp (LRFD) or (1.111.5) II, Mp (ASD). as appropriatc, of the brace about the critical buckling axis. EtCepfion:
Brace connections thot meet the requirenwflfs of Sectio/J 526.3.1 and can accommodal(' the inelastic rotations associated with brace post-buckling deformations Ileed not meellhis requirement.
Column and brace members shall meet the requirements of Section 521.2.2.
User !\lOW: HSSwallS.iil~~W$UtfenC4 (ocom.plY With thjs
requirement.
. .
526.2.5 Built-up Members
526.3.3 Required Compressive Strength
The spacing of stitches shall be such that the slenderncss ratio 1/,. of individual clements between the stitches docs not exceed 0.4 times the governing slenderness ratio of the built-up mcmber.
Bracing connections shall be designed for a required compressive strength based on buckling limit states that is at least equal to 1.111/'" (LRFD) or (1.1/1.5) II,P" (ASD), as appropriate, where Pn is the nominal compressive strength of the brace.
The sum of the available shear strengths of thc stitches shaH equal or exceed the available tensile strength of each clement. The spacing of stitches shall be uniform. Not less than two stitches shall be used in a built-up member. I30lted stitches shall not be located within the middle ane-faunh of the clear brace length.
Exception:
526.4 Special Bracing Configuration Requircmcnts
526.4.1 V-Type and Inverted-V-Type Bracing. V-type and inverted V-type SeBP shall meet the following requirements:
J.
The required strength of beams intersected by braces, their connections, and supporting members shall be determined based Oil the load combinations of the NSCP code assuming that the braces provide no support for dead and live loads. For load combinations that include earthquake effects, the earthquake effect, E, 011 the beam shall be determined as follows:
a.
The forces in all braces in tension shall be assumed to be equal to I?.J~\AI:.
526.3.1 Required Tensile Strength
b.
The required tensile strength of bracing connections (including beamH to~column connections if part of the bracing system) shall be the lesser of the following:
The forces in all adjoining braces in compression shall be assumed to be eqllal to O.3Pn.
2.
Beams shall be continuous between columns. Both flanges of beams shall be laterally braced, with a maximum spacing of Lho::.Lpi/, as specified by Equation A-I.I-7 and A-1.1-8 of Appendix A-Iof the Specification. Latera! braces shall meet the provisions of Equations A-! .6··7 and A-I.6~8 of Appendix A-I.Gor the Specification, where M ro::.M"o::.l? y ZFr (LRPD) or M,=M,,=R,ZF,. II.) (ASD), as appropriate. of the beam and Cd = 1.0.
Where the buckling oj braces about their critical bucking aJ.:is does no! cause shear ill lhe stitches, the spacing of the stitches shall be such rha! the slenderness ratio I/r of the individual elements between the stitches does nor exceed 0.75 times the governing slenderness ratio of the buiit-up member.
526.3 Required Strength of Bracing Connections
1.
The expected yield strength, in tension, of tile bracing member, determined as RyF\Ag (LRl-;"D) or RJ'~A/I.5 (AS D), as appropriate.
2.
The maximum load effect, indicated by analysis that can be transferred to the brace by the system.
As a minimum, one set or lateral braces is required at the point of intersection of the V-type (or inverted V-type) bracing, unless the beam has sufficient oUl-o[..,plane
National Structural Code of the Philippines 6
th
Edition Volume 1
5 172
CHAPTER 5 . Steel nn
strength
10
ensure stability between ildjaccnt
527.1 Scope
Bracing K·type braced frames are not permitted for SCBF.
Ordinary concentrically braced fml11es (OC13F) arc expected to withstand limited inelastic deformations in their members and conneclions when subjeclcd 10 the forces rcsuhing froln the mOlions of the design earthquakc. OCBr shalL!llcet thc requirements in this Section. OCBr tlbovc Ihe isolation system ill seismically isolated structures shall meet the requirements of Sections 527.4and 527.5and need nOl meet the requircments of Sections 527.2and 527.3.
526_5 Colullln Splices
527.2 Bracing Members
In addition (0 meeting the requirements in Section 521.4,
Oracing members shall mcet Ihe. requiremenls of Seci :oll 521.2.2.
526,4,2 K-Type
i i
i,
column splices in SCBF shall be designed 10 develop 50 perce nt of the lesser available flexural strength of the con nectcd mcmbers, The required shear strength shall be EM"c Iii (LRFD) or EMpc /J.5H (ASD), as appropriale. where £Mpc is the sum of the nominal plastic flexural strengths of th e columns above and below the splice. 526.6 Protected ZOlle The protected zone of bracing member$ in SCOF shall include the center one-quarter of the brace length , and n zone adjacent to each connection equal to the brace depth in Ihc plane of buckl ing. The prolecled zone of SCBF shall include elements that connect braces to beams and colum ns and shall salisfy Ihe requirements of Section 520.4 .
Exception.'
/ISS braces thar are filled with with this provision ,
COl1crl.'/c' lJ(~ed
flor cOII',Ay
Bracing members ill K, V, or inverted· V configurations shall have
KI/ r
S;
4J £/ Pi"
User N9te: Br1\WD.& mem~... tI,1~t lj!e desig!led as tcn~id.ii ;;;,]y (iliaCi •. tiegjecting .ih~1r ;trength .ip C9!l)Pif:iS~OI~~§ nol apprPP!iate for K. V. and Ulverted V cQnfigurnli6iis.
Such.praces m~y be used in other configurations andru:e .np1 I);!Iuired . tQ.. sati~fy .thjs .provisi9.n. ~ucb members ,!,},a),',
(~c'iude)\e,n.,q~i.i!Pgl"" •.p~~te. qr Gabl~ oracing, whh;h, are,!lqt. excluded by Seclion 519.1. .
527.3 Special Bracing Configuration
Requirements Beams in V-type and invel1cd V-type OCBF and columns in K-type OeBF shall be COnlinuous at bra( ing connections away from the beam·columl1 connection Rnd shall meet thc following requirements: 1.
The required strength shall be determined based on the load combinations of the NSCP code assuming that the braces provide no support of dead and live loads. For load combinations thai include em1hquake effccts, the earthquake effect, E. on the member shaJi be detennined as follows:
a.
l1lc forces in braces in tension shall be assumed to be equal to R.lFJA G• ror V.typc and inverted V-type
OeBr, the forces in braces in tcnsion need not exceed
the maximum force that can be developed by the system. b.
The forces in braces in co mpression shall be assumed to be equal to Q,3P w
2.
Both flanges shall be laterally braced. with a maximum
Association of Stru ctura l Engineers of the Philippines
CH/\PTUi
spacing of L" = '-I'd, as specified by Equations A- J .7-7 and A-U~-g of Appendix A-J of the SpeciflcatioJl. Lateral braces shall meet the provision.s of Equations A-I.6-7 and A-I.6-H of Appcndix A-J.6 of the Specificatioll, where M,=M,,=R\ZF,. (LRFD) or M,= Mu=/(ZF\. 11.5 (ASD), as appropriate, of the beam and C,= 1.0. As a minimum, one set of laten.d braces is required at the poillt of intersection of the bracing, unless thc member has sufficient out-of-plane strength :?nd stiffness (0 ensure <;\abiJity between adjaccnt bracc p()il1ts.
UsH Note: See User Note in Section 526;4f
"
,
':. ::";"',
: " ' .:, ~.'~:,:.":,::/:',,~,::,.~>.~{;:::.>
527.4 Bracing COllnections The required strength of bracing cOllnections shall be determined as follows. 1.
2.
For the limit state of bolt slip, the required strength of bracing connections shall be that determined llsing the load combinations stipulated by the NSCP code, not including the amplified seismic load. For other limit states, the required strength of bracing connections is the expected yield strength, in tension, of the brace, determined as R.J~\AIi (LRFD) or R/;',\A g 11.5 (ASD). as appropriate.
~i
Sluel and Mel;:ll
:;·1"1::'
528.1 Scope Eccentrically braced frames O::BFs) arc expected to withstand significant inelastic deformations in the links when subjected to thc forces resulting from the motions of the design earthquake. The diagonal braces, columns:, and beam segments outside of the links shall be designed to remain essentially clastic under the maximum forces that can be generated by the fuJly yielded and strain-hardened Jinks, except where permitted in this Section. In buildings exceeding five stories in height, the upper story of an EBF system is permitted to be desigilcd as an OCBF or a SCBF and still be considered to be part of an EBF systcm for the purposes of determining system factors in the NSCP code. EBF shall meet the requircments in Ihis Sectioll. 528.2 Links
528.2.1 Limitations Links shall meet the requirements of Section 521.2.2. Thc web of a link shall be single thickness. Doubler-plate reinforcement and web penetrations are not permitted.
Exception:
528.2.2. Shear Strength
The required strellgth oj the brace connectioll need not exceed either of the following:
tpvV", and the allowable shear strength, V,/Qv, according to
1,
The maximum for(.'(' that can be developed by the system
the limit state of shear yielding shall be determined as follows:
2.
A load (ffect based upon using fhe amplified seismic load
Except as limited below, the link design shear strength,
\I"
::: nominal shear stre ngth of the link, equal lesser of Vp or 2Mp Ie, N. rpv = 0.90 (LRFD)
527.5 OCBF above Seismic Isolation Systems
.~
The cffect of axial force on the link available shear strength need not be considered if
\
527.5.2 K-Type Bracing
1'" S 0.151', (LRFD) or
K-type braced frames are not permitted.
27.5.3 V-Type and Invcrted-V-Type Bracing. Beams in V-type and inve11ed V-type bracing shall be continuous between columns.
= 1.67 (AS D)
= "'1' Z, N-J11m = 0.6F,. A,n N = link length, mm = (d-2t t)t".
Bracing members shall meet the requirements of Section 521.2.2 and shall have
4)i·;"'".-
the
where
527.5.1 Bracing ·Members
Kif,. < -
QI'
to
1'" S (0.15/1 .5)1',. (ASD). as appropriate. \vhere
= required axial strength combinations, N
National Structural Code of tile Philippines 6\h Edition Volume 1
Llsing
LRFD
load
5- 17"
CHAPTEr. 5 - Steel MId Me tals
P"
= rcquired axial strength using ASD combinations, N = nominal axial yield strength = FJ. A", N
load
If I'u > 0.151',. (LRFD) or P" > (0.1511.5) P,. (AS D), as approp,;atc, the following additional requirements shall be met: I.
Thc availablc shcar strength ·of the link shall be the lesser of ~vV,m and 2qJVM,,,, Ie (LRFD) or V,,, I Q, and 2 (M,,,, le}/D,. (ASD), as appropriate,
where
=0.90 (LRFD)
nv = 1.67 (ASD)
and 2.6Mp IVp. 528.3 Link StitTeners Full ~ depth web stiffeners shall be provided on both sides of the li nk web at thc diagonal brace ends of th e link _The se stiffeners shall have a combined width not less than (hI' 2t w) and a thi ckn ess not 1C".."i s lh.Ul O.75tw or 10 mm, Whichever is larger, whe re hf and {ware the link \yidth and link web thickness respectively.
Links shall be provided with intermediate web stiffeners ;\'; fol lows: I.
Links of lenglhs 1.6Mp /Vp Or less shall be provided with inlenn ediatc web stiffeners spaced at intervals no! exceed ing (301w -dl5) for a link rotation angle of O.Uil radian or (52 tw -dl5 ) for link rotation angles of 0 .02 radian or less. Linear interpolation shall be used fl1:values bel ween 0.08 and 0.02 radian.
2.
Links of length grea ter than 2.6Mp IVp and less th at: 5Mp IVp shall be prov ided with intc nned iatc web sii ; fell ers placed at a dist ance of 1.5 timcs bf from cae!. end of the link.
3.
Links of lenglh between /.6Mp IVfl and 2.6Mp /V I' shall be provided with imemle<.i iale web stiffener!> meeting the rc quirements of (a) and (b) above.
4.
Intermediate web stiffeners arc not required in links of lenglhs grealer lhan 5Mp IV".
5.
Intermediale wcb stiffeners shall be full depth. Fo;' links th at are less than 635 mm in depth, stiffeners an; required on only one side of the link web. The thickness of ollc~sid ed stiffenc!'s shall not be less than tw or 10 mill, whichever is larger, and th e width shal: be not less lhan (bf /2)- lw. For links lhal arc 635 Ill'" ill deplh or greater. similar imcmlediate stiffeners arc.required 011 both sides of the web.
(Eq . 528- 1) M". = I.IS Mp
(Eq.528-2)
1', = 1'" (LRFD) or
P" (ASD), as appropriate P,. = P,. (LRFD) or 1',.11.5 (AS D), as appropriate
2.
The leoglh of the link shall not cxceed: a.
I LIS - O.5p'(A.JAg}] 1.6M"N"
whcn p' (AwIA, ) ?: 0.3
(Eq. 528-3)
nor h.
1.6Mp N ,
when p'( A,JAg} < 0.3
(Eq.528-4)
where AIV= (d - 21/}1".
pi = P,IV, and
where V, V,
Vo
= V, (LRFD) or V. (ASD), as appropriate = required shear strength based on LRFD load combinations. N = required shear strength based 0 11 ASD load combinations, N
528.2.3 Link Rotation Angle Tile link rotation angle is the inelastic angle belwecn the li nk and the beam outside of the link when the total story drift is equal to the design story drift. 6 . The link rotation angle shall not exceed the followin g values: I.
0.08 radiaos for links of length 1.6Mp /Vp or less.
2.
0.02 radians for links of Ienglh 2.6Mp /Vp or grcaler.
3.
The value detennined by linear interpolation between the above values for links of length between 1.6Mp /VI'
nal\g ~'
The required st rength of fillet welds connecting a li nk stiffener to the link web is As,FI' (LRFD) or As,Fr I 1.5 (AS D), as appropriate. where Ast j's the area of the stiffcIII!. The requ ired strength of fillet welds connecting the stifkH,'" lO the link flanges is A"F, /4 (LRFD) or A"F,. /4( 1.5) (liSP).
528.4
Link~to·Cl)lumn
Connections connections must he capable of sustainin:l. the maximum link rot~tioll angle based 0 11 the length of 11;;: link. as specified in Section 528 .2.3. The strenglh of ti ", connectio n mea sured at the column face shall equal at h' m..! th e nominal shear strength of the link, Vm as specified iil Section 528.2.2 at (he maximum link rotation angle. Link~ to ~ co lumn connections shall satisfy the above requirements by One of the following: Link ~ to ~colunlll
J.
Usc a connection prcqualified for EBF in accordance
Association of Structural Engineers of the Philippines
CHAPTEH
with Section
B~ 1.
2.
Provide qualifying cyclic I('S I results in accordance wilh Section (l·4. Resulls of:ll leasl Iwo cyclic connection tes ts shall be prov ided and are permitted to be based on one of the fo llowi ng;
il .
Tests rcpm1cd ill resca rch literature or doc umentcd tests performed for other projects lhal arc rcpresentative of project conditi ons. within the limits specifi ed in Secti on B -4 . t,
h.
Tests that are conducted specifically for the project and are represenl ativc of project mcmbe r sizcs. matcrial strcngths. connection con fi gurati ons. and match ing conncction processes, ~vi t h i n thc limits specified in Scc tion 8·4 .
exceptioJl:
Wh ere reill/iJrcem em of fhe beal1l-/()-coJlIlIIll cOl/flecfion at the link end predudes yieldillg oj fhe beam twl'r th t' reinforced leng,h. Ihl' fink is permi fl eti to be the beam seKm(~1II from 111(' eml of the reillforcemeJll 10 rh e JHacl' CorUl{lCfioll. Wh err such links (lI'{I used alld the link lellg,l! does nol exceed J.6Mp / \11', cyclic leslinc of Ihe reinforced connection is not required if rife available .r/rangr" of the rl!illforced section ami th e COlUwction eqlia/s or eXl'£'eds the required strellgrh calclilated based upon tile stra in hardened lillk as described ill Section 528_8. Full depth sfiffellers as required ill Seclioll 528.2 .3shall be placed a r the Iillk~ to- ,.eillforcem ell1 im elface.
528.5 Latcl-al Br aci ng of Li nk Lateral bracing shall be provided at both the lOp and bottom link fl anges at the ends of the link. The required Strength of each latcra! brace at the ends of the link shall be Ph = 0 .06 Mr III", where 110 is the distance between flange cClllfoids ill mill. For des ign accordi ng 10 Specificati on Section 502.3.3
(LRFD)
Mr =M,1,exp
= R)Zf~r
~
Sleel
~
l 1fj
force s and moments gCJlcralcd by at Ie.!!)! J .25 times the ex pec ted nominal shea r strength o f Ih c link RyV" , wherc V" is as defincd in Sec tion 528.2.2. The available strcngth or th c diagona l brace shall comply with Spedfical ioll Section 508. Brace membe rs shall meet the requ iremcnls of Section 52 1.2.1.
528.6.2 Beam Outside Li nk The requi red combined ax.ia l and flexural sirengt h o f Ih e bcam outside of the li nk shall be dctermined based on load combinations stipulated by the NSCP code. For lo;,td combinations including seismic effects, a load QJ shall be substituted for the term E where Q I is defincd as the forccs gencratcd by al least 1.1 timcs the expected no minal shcar strength of lh c link, RyV,,, where V.. is as defincd in Section 528.2.2. The available strength of the beam outside of the link sha ll hc ac term ined by the Speci fi catio n, llluiliplied by
Ii,,,
AI the con neclion between the di agonal brace and the beam at the link end of the brace, the intersection o f the brace and beam centerlincs shall be at the end of the link or in thc link ,
528 .6.3 Braci ng Con llectiuns The required strength of the diagonal brace connections. at both ends of the bracc. shall be at least equal to the required strength o f the diagonal brace, as defined in Section 528.6. 1. TIle diagonal brace co nn ection s shall also satis fy the requirements of Section 526_3.3 _
For des ign accord ing to Specification Section 83.4 (AS D)
M,
= M", ex"I1.5
The required brace stiffness shall meel the provisions o f Equation A ~ 1.6~ 8 of the Specification, whcre Mr is defincd ahove. Cd = I. and Lb is the link length .
528.6 Diago nal B.. ace and Beam Outside of Li nk 528.6. 1 Diago na l Bracc The required co mbi ned axial and flexural strength of th e di agoll ul brace shall be determin ed based on load combi nati ons st ipu lat ed by the NSCr code. For load combi nati ons including scismic effec ts, a load QI shall be substituted for th e term E, where Q l is defincd as the axia l
No part of Ihe diago nal brace conncc tion at thc link end of the brace shall cxtend over the link length. If the brace is des igned to resist a pOI'lion of the link end moment , then the diagonal uf
528.7 13ca m-to-Co!UIIlIl Connec ti ons If the EI3F system factors in Ihe NSC P code require moment resist ing con ncctions away frolll the link, th en the be.mHOco lumll connections away from Ih e lin k shall mect the requirement s for bcaJll-lo-column connections for OMF specified ill Sections I 1.2 and 11 .5.
Na tionat Structural Code of Ille Philippines 6'" Edition Volume 1
5- 176
CHAPH: 1i
~
. Sleel (lnd Me tals
If the EBF system fll 1:IOI"S in the NSCP code do not require moment resistin g cOllnections away from the ti!lk . then the bcam-lo-colulIlli conllections lIW,lY frolll the lin k arc pennillcd 10 be designed as pinned in the plane oflhe web.
SECTION 529 BUCKLING-RESTRAINED BRACED
528.8 Required Strength of Columns
529.1 Scope Buckling-restra ined braced fram es ( BRBFJ; arc expected In withstand significant inelastic deformations when subjected 10 the forces resulting from the moti ons of the design eanhquake. DROP shall meet the requirements ill thi s Section. Where th e NSCP code docs not contain design coefficieflls for BRBF, the pro visions of Section B-3 shall apply.
In addit io n to the requiremcnts in Section 52 1.3. the req uired stren gth of columlls shall be det erm ined from load combinatiolls as stipul;l(ed by the NSCP code, except that the seismic IO,ld E.sJmll be the forces gencnHed by 1.1 limes the expected nominal shear strength of all links above the level under considertll ioll . The expected nominal s h e~ r strength of a link is RyV/lI where VII is as defined ill Section
FRAMJ£S'il\JinF) · ..
."
.
528.2.2.
Column members shall meet [he requirements of Section 521.2.2 .
528.9 Protected Zolle
Links in EBFs 3re a protected zone, and shall satisfy the req wrements of Section 520.4. Welding all links is permitted for attachment of link stiffeners, as required in Section 528.3.
528.10 Demand Critical Welds Complete-joint-penClration groove welds attaching the link flanges and the link web to the column are demand critical
529.2 Bracing Members Bracing members shall be composed of a structural steel core and a system tlim restrains the steel core frolll buckling. 529.2.1 Steel Core The steel corc shall be designed force in the ~race.
10
res ist Ihe en tire axial
The brace design ax ial strength , fl)F'y." . (LRFD), an d the brace allowable axial strength, PrJ'· /0 (ASD), in tensi on and compression, according to the limi t slate of yield ing, sha ll be determined as follows:
welds, and shall satisfy the r~qujrement s of Section 520.3.2.
(Eq. 529- 1)
~
0.90 (LRFD)
!l
~
1.67 (AS D)
where
Fysc
= specified minimum yield stress of the steel core,
Asc
or actual yield stress of the steel core as determined from a coupon test, MPa. =net area of steel core, 111m2.
Plates used in the steel core that are 50 mm thick or greater
shall satisfy the minimum notch toughness requirements of Sec ti on 519.3.
Splices in the stcel core are not permitted. 529.2.2 Buckling-Restraining System The bucklingM restraining sys tem shalt consist of the casing for th e steel co re. In stability calculations, beams, columns, and gu ssets connecting the core shall be considered part s of this .system. The buckling-restraining system sha ll limit local and overall buckling of lhe steel core for deformati ons corresponding to 2.0 times the design story drift. The buckling -rest n~ ;Jl illg system shall not be permitted to buckle within defonnhiions corresponding to 2.0 times the design story drift.
Association of Struct ural Engineers of the Philippines
User Not.c:Con{onnance t~ thi~ Wf>)'ision is qempnslraled by means of testing as described in S¢lltioh5;!9,2,3, 529.2.3 Testing The design of braces shall be based upon results from qllalifying cyclic lests ill accordance with the procedures and acceptance criteria of Section 13-5. Qualifying tcst results shall consist of al least Iwo successful cyclic tests: onc is required to be
it
test of a brace subasscmblage thaI
includes brace connection rotational dcm:lI1ds complying with Section B-5, Section B-5.4 and the other shall be either a uniaxial or a subasscmbJagc test complying with Section 13·5, Section 13-5.5. Both test types arc permitted 10 be b~lscd
!.
529.3.1 RC
The required strength of bracing connections ill tensioJl and compressioJl (including bcam-to~~:()lul1ln connections if part of the bracing system) shall be I. t times the adjusted brace strength in compression (LRFD) or 1.111.5 times the adjusted brace strength in compression (ASD).
upon one of the following:
Tests reponed in research or documented tests
performed for other projects. 2.
corresponding to 2.0 times the design story drift) to Fr." of the test specimen. The larger value of (0 from the two required qualification tests shall be used. Where the tested stec! core material docs not match that of the prototype, (I) shall be based on coupon testing of the prototype material. 529.3. Bracing Connections.
Tests that are conducted specifically for the project.
Inlerpolation or extrapolation of test results for different member sizes shall be justified by rational analysis that demonstrates stress distributions and magnitudes of internal strains consistent with or less severe than the tested assemblies and that considers the adverse crfects of variations in material properties. ·Extrapolation of lest results shall be based upon similar combinations of steel core and buckling-restraining system sizes. Tests shall be permitted to qualify a design when the provisions of Section B-5 are mel.
529,2,4 Adjusted Ilrace Strength \\'here required by these Provisions, bracing connections and adjoining members shall be designed to resist forces calculated bi1sed on the adjusted brace strength.
529,3,2 Gusset Plates The design of connections shall include considerations of local and overall buckl.ing. Bracing consistent with that lIsed in the tests upon which the design is based is required. User Note: This provision may bernet by designing tile for a..lfan,$VerSe f9rc~ cQD.sisteQt wi~).Jrap.sverse bracing forces qetermilled from • testinl\, by~dqing a stiffener to it to re~i$ltl~s, fOrc~,or by providing ab.race to the gt\sset plate or to !he bra"" i!!;elf. Where ,clwsupporting tests didnN,includetransverse ~racing, ,nosucbbracingis required. A~y attachment of bradng· to the ·sieel core ·must be included in the qualification testing, gus.s~t p'l~~e
529.4 Special Requircmcnts Related to Bracing Configuration. V-type and invcrted-Vtype braced frames shall meet the following requirements: I.
The required strength of beams intersected by braces, their connections, and supporting members shall be determined based on the load combinations of the NSCP code assuming that the braces provide no SUpp0l1 for dead and live loads. For load combinations that include earthquake effects, the veI1icai and horizontal earthquake effect, E, on the beam shall be detennined from the adjusted brace strengths in tension and compression.
2.
Beams shall be continuous between columns. Both nanges of beams shall be laterally braced. Lateral braces shall mect the provisions of Equations A-I.6-7 and A-l.6-8 of Appendix A-l.6 of the Specification, where M, ~ M" ~ II, ZFv (LRFD) or M, ~ M" ~ II,. ZF\' /l.S (ASD), as apPI:opri·ate, of the beam and Cd ~ I.e). As a minimum, onc set of lateral braces is required at the point of intersection of the V-type (or inverted vtype) bracing, unless the beam has sufficient out-ofplane strength and stiffness to ensure stability between adjacent brace points.
The adjusted brace strength in compression shall be fJwRyPysc. The adjusted brace strength in tension shall be
(vRJ\ . \(". EJ..:ception: The factor R.I· need nol be applied if Fnc is established using yieid stress determined from a coupon· lest.
The corn pression strength adjustment factor, rl, shall be calculated as the ratio of the maximum compression force to the maximum tension force of the tcst specimen measured from the qualification tests specified in Section 13-5, Section 13-S.6.3for the range of deformations corresponding to 2.0 times the design story drift. The larger value of [) from the two required brace qualification tests shall be used. III no case shall 13 be taken as less than 1,0, ~
The strain hardening adjustment factor, cu, shall be calculated as the ratio of the maximum tension force measured from the qualification tests specified in Section B5, Section B-S.6.3 (for the range of deformations
Uscr Note: The beam has. sufficient oUI,of-plane strength and stiffness if the beam bent in the horizontal plane meets
th
National Structural Code of the Philippines 6 Edition Volurne 1
5 · 178
CHt\I)T I::r~ !j -
Sleel an(i MelJI:·>
For purposes of brace design and jesting. the calculated ma xi mum deform atioll of braces sha l! he increased by including th e effect of the vertical deDcction of the beam und er the loading defined in Section 529 4. K ~ I Ypc braced frames Hrc not penniltcd I.:'":: 9ROF.
529.6 Protected Zone The protcctcd I.o nc sh.1l1 include thc steel tore of' h rac ing members and clements that connccl1hc steel core to hea ms and columns, and shaH satisfy th e requirements of Section 520.4 .
529.5 Beams and Columns Beams and columns in BRBF shall meci the following requirements. 529.5.1 Width-Thickness Limitations Beam and column members shall meet the requirements of Section 521. 2.2.
529.5.2 Required Strength The required strength of beams and columns in BRBF shall be determined from load combinations as stipulated in the NSCP code. For load combinat ions lhal include earthquake effects, the canhquakc effect, E, shall be determined from the adjusted brace strengths in tension and compression. Th e required strength of beams and colu mns nced not exceed the maximum forc e thal can be developed by the system.
529.5.3 Splices In addition to meeting the requirements in Section 52 1.4: colu111n splices in BRI3F shall be designed to develop 50 percent of the lesser available flexural strength of the connected members, dctermi ncd based on thc limit Slale of yielding. The required shear strength shall be l.Mpc !II (LRFD) or EMpc 1I.5H (ASD), as appropriate, where EMpc is the SlIm of the nominal plastic flexural st rengths of the columns above and below the splice.
Association 01 Structural Engineers of the PI1 ilippines
530.2.3 Openings in Webs Opening:-; in webs shall be bounded 011 all sides by H BE (lnd VUE extending the fill! width and heigh! of the panel , res pec ti ve ly, unl ess otherwise ju:-;tificd by t(' siing and ana lysis.
530.1 Scope Special plate shear wall s (SPSW) afC ex pected 10 withstand significant in elastic deformations in the webs wh en subjected to tile forces resulting from the motions of th e design cJ rlhquakc. The horizojHal bound ary clements (HBEs) and vertical bou ndary elements (VBEs) adjacent to Ihe webs shall be designed 10 remain essentially elastic
530.3 Connections of ~'c bs to Boundary Elements The required stren gth of web co nn ec tions to th e surro unding HBE and VBE shall equal the expected yield strength, ill tension, of the web calculat ed at nn a!lgl·~ ll. dcli ncd by
under the maximum forces that can be generated by the fully yielded webs, except that plastic hin ging at the ends of HBEs is permiUed. SPSW shall meet the requirements of
530.4 Horizontal and Vertical Boundary El ements
this Section. Where the NSCP code docs not contain desi gn coeffi cients for SPSW, the provisions of Section B-3 shall apply.
530.2 Webs 530,2.1 Shear Strength The panel design , hear strength, q> V" (LRFD), and the a llowable shear stren gth, V,/Q (ASD), according to the limit s tale of sh ear yielding, shall be detennined as follows:
V" ~ 0.42 P,. 'w L,rsin 2a
(Eq .530-1)
n ~ 1.67 (ASD)
'" ~ 0.90 (LRFD)
where 1".
== thicknes$ of the web, mm.
L er
= clear distan ce between
VBE flanges, mm .
a is the angle of web yielding in radi ans, relative to the vertical, and it is given by:
itS
measured
IIIL
tan
4
I +-2A
=
A" AI'
1(. L
The req uired stren gth of HB E shall be the greater or the forces cOITcspondi ng to th e expected yield strength , in tension, or th e web calc ul ated at an ,mglc a or th'lI determ ined from th e load combinations in the NSCP code assuming the web prov ides no su pport for grav it y loads. The beam~coJumn mOlllent rat io provisions in Secti on 522.6 shall be met for all HBf.YVB E intersecti ons with out consideration of the effects of the webs.
530.4.2 HB['· to- VBE Connections J-m E~ to- VBE conn ections shall s.uisfy the req uirements of Section 524.2, The required shear strength, VI" of a HBE-toVB E connection s hall be determined in accord;:1I1ce wi th the pro vis ions of Secti on 5.24.2, except that the required shear strength shall not be less than the shear correspond ing to moment s at each end equal to I.IR,M" (LRFD) or ( 1.111 .5)
+,,, "(1~ + 36i~~L J (Eq .530·2)
iI
530,4.1 Required Strength In addition to the requi re ments of SCt.1ion 52 1.3, the required stren gth of V8 E shall be based upon the forces corresponding to the expected yield st rength , in tension , or the web calculated at an angle n.
R)Mp (ASD). as appropriate. together with the shear resulting from the expected yi eld strength in tension of the webs yielding at an angle a.
c
I
Eq .S30-2.
== distance between HU E centcrlincs , mill.
=cross~scc ti ona l area of a HB E, mm2. = cross-sectional area of a VI3E, 111m2 . = moment of inenia of 11 YBE take n perpendicular to the direction of the web plate line, mm4 . = disl:m cC'- bet ween YBE ccnl crlin c:-; , mill.
530.2.2 Panel Aspeel Ratio The rat io of panel length to height, VIT, shall be limited to 0.8 < Vii 50 2. 5.
530.4.3 Width-Thickness Limitations HB E and VBE members shall meet the requ irements of Section 521.2.2.
530.4.4 Lateral Bracing HU E 511nll be lalernll y braced at all intersections with VI3E and 11t a spacing not to exceed 0.086 RJ:JF.,.. 1301h fl anges of HB E shall be braced ei ther directly or indirect ly. The required strengt h of lateral bracing shall be at least 2 percellt of lhe HBE fl ange nominal strength, P,. bf tf. The requi red stiffness of all lateral bracing shal t' be detcnnined in accordan ce with Equation A-I .6-8 of Appendix A-I .6 of the
Specification. In these equations, Mr shall be co mputed
11S
RJZP,. (LRFD) or Mr shall be computed as R)ZF,. 11.5 rh National Structural Code of Ihe Plli1ippines 6 Edition Volume 1
(AS D), as appropriat e, and Cd ::: I.O.5l0. 4. 5. VB E Splic.:cs . VBE ..:pl icc..: ..:hall com pl y wit h 11K'. n:quirenH:ms oj" Sectio n 521.4. 530.4,6 Pancl Zoncs
531.1 Senpe
Thc VUE pa nel i'.olle next 10 the lOp and h;I SC !-IBE of the SPSW sha ll com ply wi th the requin~ll1 e nl s in Sec ti on 52 2.3 .
When required by the NSCP code or th e cnginccI"Hof'· rccord, a qmdi l), ass urance plan shall be pro vided . The qu ,llil y assurance plan shaH in cl ude the requirement s or Sc<.:ti on H2.
530.4.7 Stiffness or Vcrtical
BOllnd ~ II'Y
Elcments
The VBE slwl! have momc nt s o f in~rt i: 1 about an axis taken pcrpendicu lar 10 Ihc plane 01" the web, I" 110t less th an 0.00307 "" MIL.
User Note: The
consider~d ad'''luate.
of a response modification factor of 3 or '
assumption of system, clement, and ~:~~~.: ~;~I~~~J~~ reduce design forces. The qualily assu""""",e to ensure thaI the seismic . .sy'sfe.rl.:~;,:;is significantly free of defects that . ·tMiJ&:·llj[ ductility of the system. There may be cases . non-redundant major transfer members; or whereWot'Kftff penonned ·in a location that is difficult t
examp}e;
program .
'~~~i :'"
Association of Structural Engineers of the Philippines
PARTB' APP}!;NDICES B·1. PItEQUALIFICi\TION OF BEAM,:COLUMNANDLINK.tO.
cotoMNcdNNECTIONS
B- I.l Scope 'nli s appendix contains minimum requirements for prcqualificntion of beam to-column mOJllent connections ill special moment frames (SMF), intermediate moment frames
The CPR» sha ll ;!lso provide the sam e informa tion when limits arc It) be changed the COIiIlCt:tioll has the ability and reliabilit y 10 undergo the required illicrstory d!'in angle for SMF and IMI~ and the required link rotati on ilngle for EBF, where the link is adjacent to columns . The limits on member sizes for prcqualificatioll shall 1101 c,x<.:ccd tile limits spc.cificd in Section 13-4. Section 13·2's.2.
n· 1.4 Prcqualification Variables In order to be' prequalified, th e effect of the following
(lMF), and Iink-to-colul1ln conn ection s in eccentricall y
variables on connection performance shall be conside red. Limits on the permissible values for each variable shall be eSl
braced frames (EBF) , Prequalified connections arc penni lied 10 be used, within the applicable limi ts of
I.
Beam or link parameters:
a.
Cross-section shape: wide na ngc, box, or other
b.
Cross-section fabric:l! iOIl method: rolled shupe. welded shape, or other
c.
Depth
d.
Weight per foot
c.
Flange thickness
f.
Material specification
g.
Span-ta-depth ratio (for (for EBF)
h.
Width thickness ratio of cro ss-sec tion clements
I.
Lateral bracing
j.
Other parameters peninent to Ihe specific con necti on under consideration
2.
Column parameters:
Cross-section shape: wide flange, box, or mile!'
b.
Cross-section fabrication meth od: rolled shape. welded shape, or other
c.
Column orientation with respect to beam or link: beam or link is connected to column flange, beam or link is connected to' column web, beams or links are connected to both the column flange and web. or other
d.
Depth
c.
Weight per foot
r.
Flangc thickness
g.
Material specification
h.
Width-thickness ratio of cross-section elemcnts
i.
Lateral bracing
j.
Other parameters pCI1incnt to tile specific connection under consideration
prcqU
requirements of these Provisions, the limits of prequalilicatioll and design requirements for prcqualiricd connections shall govern.
B-I.2 General Requirements B-1.2.1 Basis for ('re'lualiticalion
Connections shall be prcqualificd based on test data sat isfying Section 8-1.3, suppot1ed by analytical studi es and design models. The combined body of evidence for prequalification must be sufficient (0 assure that the con nection can supply the required inlerslory drif[ angle for S MF and IMF systems, or Ihe required link rotation angle for EBF, on a consistent and reliable basis withi" the specified limits of prequalification . All applicable limit states for the connection that affect the stiffness. strength and deformation capacity of the connection and the seismic load resisting system (SLRS) must be identified. These include fracture related limit states, stability related limit states, and all other limit states pertinent for the connection under consideration. The effect of design variables listed in Section B- lA shall be addressed for connection prequalification. 11-1.2.2 Authority for Prcqualification
Prcqualificat ion of a connection and the associated lim its of prcqualitication shull be established by a connection prcqualification review panel (CPRP) approved by the authority having jurisdiction . Section U-1.3 Testing Requirements Data lIsed to SlipPOll conneclion prequalifiCfllion shall be based on tests conducted in accordance with Section 13·4. The CPRP shall determine the number of tests and the variables considered by the tests for connection prequalification.
National Structural Code of the Philippines 6'h Edition Volume 1
SMF or IMF), or link length
3.
Bcam (or link) colu mn relat ions:
the
iI.
Panel zone sl rcnglh
h.
Doubler pl;lI c all ac hmcl1t det'lils
c.
Column ·bea m (or li nk) 1l1OIllcni r
4.
Continuit y platcs :
a.
Idcl1t ific.uion c< conditions under whi ch contin uity plates arc rcquir-.;u Thi ck ness. widt h and de pl h
c.
Atlachment d eta il s
5.
Welds:
a.
Location, ex tent (including ret urn s), type (CJP, PJP, fill et, CIC.) and an y reinforcement or co nt ouri ng required
h.
Fi ller me tal classiliCluion st rength and lIolch toughness
c.
Detail s and Irca(mCIlI of wel d b':lck in g and weld tah!)
d.
Weld access holes: size, geometry and fi nish
c.
Welding q uali ty control and qu ality ,\ssurancc beyond that described III Secti on 18, including th e nondestructive tes ting (NOT) method, inspec.tion frequency, acceptance criteria Imd docu mentation requirements
6.
Bolts:
a.
Bolt dia meter
b.
Bolt grade: ASTM A325. A490. or other
c.
Installmioll requirements: prctcilsioncd, snug-tight, or other !-lole type: standard, overs ize.
$ho r{ ~slot,
long-slot, or
other c. f.
connec tion hy the CPRP
consideratio n,
as
B-l .6. PrC
General dcsc riplion of the prcqu alified connec tion an d drawings th at dea rl y identify key fea tures and components of th e cOllnection
2.
Descripti on of the expected behav ior of the connection in the clastic and ine lastic ranges of behavior, intended )ocati on(s) of inelastic
3.
Listi ng of systems for wh ich connection is prequalified: SMF. IMF. Of lOBI"
4.
L..ist ing of li mits for all prcqualificati on variab les listed in Section 13- 1.4.
5.
Listi ng of deman d cril ical welds
6.
Definiti on of t he region of the co nnection th at co mprises the protec ted zone
7.
De tailed descri ption of the design procedure for the connection. as req uired in Section B- 1.5.
8.
Lis t of references of test reports, research reports and other publications th at provided the basis for preq ualiflca ti on
9.
SUlllmary or quali ty co ntrol and quality assurance proced ures
Hole fabricati on method: drill ing, punching, su bpunching an d rea ming, or other
Other parameters pertin ent to the specific connection un der co nsideration
7.
Work manship: All workma nship para illcle rs lhat exceed AlSC. RCSC and A WS requ irements, pCl1incnt to the specific connecti on und er consideration, sllch as:
a.
Surface roughness of thennal cu t or gro und edges
b.
Cutt ing to lera nces
c.
We ld reinforcement or con touri ng
d.
Presence of holes, fasteners or we lds fo r aUachmellls
8.
Additional connecti on detail s: All variables pertinent to •.~
un der
B-I.S. Design Procedu re A comprehensive design procedure must be available fo r a prcqualificd co nnec liull. The design procedure must add ress all applicabl e li mi t states within the limits of preq uali fication .
h.
d.
specific
e~labljshcd
Association of Structural Engineers of the Pllilippines
C:HI\Pil: l~
5
!)teel
:)- HB
I.
M;lIcrial test rcpOJ1S for structura l steel, boll s, shear conncctors. and we ldi ng materials
11-2.1 Scope
2.
Inspcction procedures
Quality control (QC) and quality
3.
NOIK'o nforrnancc procedure
4.
Matcrial cont rol prm;edurc
5.
Bolt installation procedure
6.
Welder perform,wee qualilicalion record s (WPQR j, including any suppl emental testi ng req liiremellls
13-2.2 Inspection and Nondest ructive Testing Personnel Visual welding inspection and nondestructive testing (NOT) shall be cond~Jctcd in accordance with a written practice by personnel qualified in accordance with Section B-6.
7.
QC Inspec tor qualifi cations
8-2.4 Quality Assurance Agency Documents
Bolting inspection shall be conducted in accordance with a written practice by qualified persollnel.
B-2.3. Contractor Documents The following documents shall be submitted for review by the engineer-of-record or designee, prior to fabricat ion or erection, as appl icable:
1.
Shop drawin gs
2.
Erection drawings
3.
Welding Procedu re Specifications (WPS), which shall
specify all applicable essential variables of A WS D I and the foll owing, as applicable a.
po wer source (constant current or constant voltage)
b.
for demand cri tical welds, electrode manufacturer and trade name
4.
Copies of the man ufacturer's typical certificate of confonnance for all electrodes, fluxes and shield ing gasses to be used. Certificates of conformance shall satisfy the applicab I~ A WS AS requirements.
5.
6.
For demand critical welds, applicable manufacturer's certifications that the filler metal meets the supplemental notch toughness requirements, as applicable. Should the filler metal manufacturer not su pply suc h supp lemen tal certifica tions . the contractor shall have the necessary testing performed and provide the applicabl e test reports. Manufacturer's product data sheets or catalog d'lta fo r SMAW, rCAW and GMAW co mposite (cored) filler
metals to be used. The data sheets shall descril?c the product, limitations of usc, recommended or typica l welqing parameters, and storage and exposure requirements, including baking, if applicab le. The following documents shall be available for revi ew by the engineer-of-record or designee prior to fabrication or erection, as applicable, unl ess specified to be submitted:
The agency responsible for qualit y assurance shall submit the following docum ents to the authori ty having jurisdiction, the engineer-of-record, and the owner or owne r's designee: !.
QA agcncy's written practices for the monitoring and control of the agency's operations. The wrilten practice
sha ll include: a.
The ;tgency's procedures for the selection and admini st ration of inspection personnel, describing the trainin g, experience (\nd examination requirements for qualification and certificati on of inspection personnel ,
and b.
The age ncy's inspection procedu res, including general
inspection. material controls, and visual inspection
weldin g
2.
Qualifi cations of management and QA personnel desi gnated for the project
3.
Qualitic
4.
NDT procedures and equipment calibration records for NOT to be performed and equipment to be used for the
and
NDT
project 5.
Daily or weekly inspection repoI1s
6.
Nonconformance reports
B·2.5 Inspection Points and Frequencies
Inspection points and frequcncies of quality con trol (QC) and quali ty ass urance (QA) tasks and doc umentation for th e
seismic load resistin g sys tem (SLRS) shall be as provided in the followin g tables. The following entries are used in the tables:
Observe (0) . The inspector shalT observc these functions on a random, daily basis. Weldin g operation s need not be delayed pending observations.
National Structural Code of the Philippines 6'h Edition Volume 1
(
...
!) · 184
CHAP "t t:1i!~
··
Stl:el and tv1etat5
Perform (1') - These inspections shal l be performed prior to tIll: !ina! acccpt ,lncc or the item. Where a task is noted to be pcrf{)J"Jllcd by both QC and QA, il shall be pCfJJliltcd to (:oordinale the inspection fU llc tion bel ween QC and QA so tlllli the inspectio ll fUllct ions need he performcd hy only one p'lrty. Where Q/\ is to rely upon inspection rUllctions performed by QC, the approval of the engineer-of-record Clnd the authority having jurisdiction is required. Doculllent (I)) ~ Thc inspector sh.}11 prepare reports indicming that the work has been performed in acc'lmJance with the contract docullleJlts. The repol1 need Jlot provide dctclilcd measuremcnts for joint fit-up, WPS scltings, complctcd welds, 01" . other individual items li sted in the Tables ill SCCliolls B-2.5.I, B-2.5.3, or B-2.5.4. For shop fabrication. Ihe report shall indicate the piece mark of the piece inspected. For field work. the report shall indicate the reference grid lines and floor or elevation inspected. Work not in compliance with the contraCt documents and whether til e noncornpliance has been satisfactorily repaired sha ll be /loted in the inspection rerml. B-2_5.1 Visual Welding Inspection
Visual inspection of welding shall be (he primary method used to confirm that the procedures, materials, and workmanship incorporated in construction arc those that have been speci fied and approved for the project. As a minimum, tasks shal l be as follows: B-2,S,2 Nondestructive Testing (NOT) of Welds Nondcstnlctive testing of welds sha ll be performed by qualit y assurance personnel. I.
Procedures
Ultrasonic tcsting shall be performed by QA according {o th e procedurcs prescribed in Section B-6, Section 13~6.1. Magnetic particle tes ting shall be performed by QA according to the procedures prescribed in Section B~6, Section B-6.2. 2.
Required NDT
a.
k-A rea NDT
When welding of' doubler plates, continuity pllnes. or stiffeners has been performed in thc k-arca, the web shall be te.sted for cracks lIsing magneti c particle testin g (My). The MT inspection fuea shall include the k-arca bnsc Tlletal \." ithin 75 Illill of the weld.
b.
c.
Base Metal NDT for Lamellar Tearing and Laminations
After joilH cOlllplction, base mC1i'1i thicker than J1-\ 111m loaded in tension in the through Ihickncss direction in lee and COffler joints. where the conn ected !Hateri,,! is great er than 19 mill ;lild con tains CJP groove welds. shill I be lIltrasonically tcsted for discontinuities behind and adjacent to the fusion line of such welds. Any base met;:}1 dbwvIltinuities fOlllld within tJ4 or the steel surfac.:e shall be accq>tt!d or rejected on the basis of criteria AWS D 1.1 Table 6.2, where t is thc thi ckness of the P;:111 sul~icC1Cd to the Ihrough~thickJlcSS strain .
or
d.
Beam Cope and Access Hole "DT
At welded splices an d connection!>, thermally cui surfaces of beam copes and access holes shall be tested lIsing m;lgnctic particle testing or penctrant tcst ing. when the nangc thickness ex.ceeds 38 mm for rolled shapes, or when the web thickn ess exceeds 38 mm for built-up shapes. c.
Reduced Beam Section Repair NDT
Magnctic particl e test ing shall be performed all :IIlY weld and adjacent area of the reduced bC
Weld Tab Removal Siles
Magnetic particle testing shall be performed on the end of welds from whi ch the weld tab s have been removed, except for continuity plale weld tabs. g.
Reduction of Percentage of Ultrasonic Testing
The amount of ultrasonic testing is permitted to be reduced if approved by the eJ1gitleer-of~rccord and the authority having jurisdiction. The nond estructive testing rate [or an individual welder or welding operator may be reduced to 25 percent, provided the reject rate is demonstrated to be 5 percent or less of the welds tested for the welder or welding operator. A sampling of at least 40 completed welds for
Cll' Grbove Weld NDT
Ultrasonic testing shall b.e performed on 100 percent or CJP groove welds in materials 8 mm thick or greater. Ultrasonic res ting in materials less than 8 mm thick is not required. Magnetic panicle \esting shall be performed on 25 percent of ali beam-to-column Cll' groove welds.
h.
Reduction of Percentage of Magnetic Pm1icic Testing
The amount of MT on ell' groove welds is permitted to be reduced if approved by the engiJleer-of~record and the authority having jurisdiction. The MT rate for an individual welder or welding operator may be reduced to 10 percent,
Association of Structural Engineers of tile Philippines
provided the reject nte is delllonstntecl to he '5 percent or less of the welds tested for thc welder or welding operator. A sampling or at !east 20 completed welds for a job shall be made for sueh reduction evaluation. Reject rale is the !lumber welds containing rejectable defects divided by the number of welds completed. This reduction is nOI permitted on welds in the k-area, at repair sites, weld tab and backing removal sill'S and access holes.
or
r-,7 V"'is-u-a]-;--'j"n-sl'-ec-,-:u"o--n---;;T"'a'7 sk - -
WPS followed - Selling on welding
--~~.~~~-~~~~~.
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.. '.I.'.r(ly.~.I .. ~p'~~.~J. - Selected welding
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-o-C----- ------QA'----:i _-"~4~;;~;~I\~;gg;;S {y;;c;iT(,;;;-
Before Welding Task Doc, _ Task DOc, f--77-'~:--:'::;=~-c:--Material idelltifica!iol1 0 0 (Type/Grade) __________ ~ _ _ __ Fit-up of Groove Welds (including joint g~om~L ~ Joint rreparation
...~. DiIII cl-;<;i~)-;~~<;-(~ll j W1 mcn-t:-P/O** root opening, roo! race,
o
bevel)
- Cleanliness (condition of _.~!~~l sur!~~~~.L ______......._____ _ - Tacking (tack weld
.. "'.~.': ... _ _ _ _ _ I__ ~ - Backmg type and fJl (II P/OH 0 applicable) _~ --.-;c:-- _____ ___ ~ Configuration and finish of 0 0 quality. and location),
Task I-,;;---c,..:
Visual inspection During Welding
o
ratc,, ___7C'-:-_______ _ - Preheat applied - Interpass temperature
o
maintained (rnin.lmax.) - Proper position (F, V,H,
_.mlt____ ___ ._. ___.._____ - Intermix of filler metals ._~\voi~_~~._~~~~I_~~~.~IPp~~~~~.~_. __ ---;::------ ~~___ -;:::---- .____ .. .__~~~_~.~~C~L~\.~~.£~.~_~. .~::.~~~~E:~~_. ~. ......~Q 0 COl1trol and handling of welding conslJ!nables
.. :..... Pac k
"j~~y·;7:~)!1-;1;~~(;1~Z;~dili~;~---
- Wind speed within limits - Precipitation and te m per~~l..!..~·~ __.__ .m_. _______ ~._" ___ _
o
o
.____.__._.______ _
o
o
access holcs_~ _ _ _ ------I----/-------i Fit·up of Fillet Welds Welding techniques - Dimensions 9alignmcnt, () - Intcrpas;- <~Ild final o gaps at root) cleaning - Cleanliness 9condition of P/O** o --~+---J----j.---·. ·=-Each pass within profile slee.! surfaces) Imitations - Tacking (tack weld o o - Each pass meets quality quality and location) requirements .. _______ .. __ **Foll()wing pcrforln~i"iluoftl;Tsill~I;;"ctTo~l-·-(ask for len ----.--+---l~_____I NO-~~eld i J1g·o~~;:·-c;~~(j
tll
National Structural Code of the Philippines 6 Edition Volume 1
~)-
1HCi
Yls~;H ...
CHAPTHi :) . Steel and Metals
InSpection
Tasl(
AfieiWCld.ltig
.. x A .. QC Task ])0",.. TililK \1)OC1 0
Welds cleaned Welder idc;i'iTifc~;;tioll -_. __ ..-
legible
0
0
-
..
Vcrify size, length, and 0 location or welds - - --_.\!F;:l!ly inspect welds t o ~!ilnc~ criteria ... __..- Crack porhibitiol1 Weld/base-metal fusion - Crater cross*section P
--
- - _.__._. -
0
._-_
D
P
.~.-
~
---~
fillets --Backing bar:<;-~C~10ved alld weld tabs removed and . finished (if required) Rcoair activities
~-.-
--_.-.
~--
i
--
p
D
D
P
Inspeclion Solting
----_. p
j)
P
D
P
D
3.
QA
Bolting Task Doc. Task - Proper bolts selected for 0 0 the joint detail Proper bolting procedure 0 0 selected for joint detail Connecting clements arc fabricated properly, including the appropriate faying surface condition 0 o and hole preparation, if specified, meets applicable requirements r-===~-----+--I---~-·-----p
D
()
Doc.
-
0
.. _~)~er ras~~!2.~~",~!.l~I?Q~CI1[~~ ~~ ___.____ .. __
---
--I
QA
QC
Task
Doc.
Task
bos]
p
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D
_ __
... ... ...-
Documentation
All NDT performed shall be documented. For shop fabrication, the NOT report shall identify the tested weld by piece mark and location 111 the piece. For field work, til:,' NOT feparl shall identify the tested weld by location in the structure, piece mark, and location in the piece.
-
B-2.S.3 Inspection of Bolling Observation of bolting operations shall be the prima;,y method used to confirm that the procedures, m
---D
...._ .. ----- ---·-1-------1 0
After
p
QC
Inspection Task Prior to
Task
Document accepted and rejected connections
-~--~--~~~~----'----~~----.---~~--,
Pre-installation verification testing conducted for fastener assemblies and method used I-"'="'-"=-~----- . Proper storage provided for bolts, nuts, washers, and
QA
Task:. "~
~- - .---.
- Weld profiles Weld size - Undercut _._---- Porosity Placement-or reinforcement
..QC. .. ·,Task· Poe!
"'---~---
--
D
...
Task . P~(itlll ,
Fastener assemblies placed in all holes and washers (if () 0 required) arc propcrly positioned ------_._.__. .. ... ....Joint brought \0 the snug 0 0 tight condition prior to thw 1 pretem;ioninp- operation .. ----_. __. ._--Fastener components not 0 0 returncs by the wrench prevented from rotating ------- - - - - ----Bolts arc pretensioned progress systematically 0 0 from most rigid point toward free edges
0
--_
-----
!qspeG~on
lOIWi1!g ..••
B-2.S.4 Other Inspections Where applicable, perfonl1cd:
the
following
inspection
be
shall
QCQA
Other Inspection Task
/--;;-;-_-,--_ _~---+-T'c!a~s"-k+",D:<:>o,:cc'__1_'as~k
.I?;
Reduce beam section
(RI3S) requirements, if _"JljJlicabJc .. .•-- - .. ,
",.,".~
p
\)
P
j)
~
- contour and finish - dimensional tolerances Protccted zone-no holcs--'--'-- .-.-... ~.---- .~----.. ------~·+'"·---··------i and unapproved attachments made by contractor ...---.... ----- .----
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Association of Structural Engineers of tile Philippines
D l _
I I
B·3. SEISMIC DESIGN COEFF'lC~N'l'~*~R
'.
APfJlQ~TE':~EiUQJ)··.;
PARAMETERS · ". .' . . .... . . fl·3 .l Scope This apPl'.ndix contains des ign cocmcicnts, sys tem lim itat ions and design panl mcl Crs for seismic load resisting systems (SL.RS) that ,Ire incllJdcd ill th ese Provisions but 1101
yet defi ned in thi s code for bllCk!illg ~ rcstraincd braced
frames (BRBF) and special pl ate shea r walls (S PSW). The
values prcsclHcd in Tables B-3-1 and 13-3-2 in this appendi x shall only be used where neither Ihe NSCP code nor
SEIIASCE 7 contain such va lues.
.
User Nciie:The design. co'dficicnts' :and . parameters prcse\l~1f:$\~' aOPf~
7 an~ : Ulis
codes .acld the. BRBl'illldSPSW tatli~irlis,t of acCcpmhlc strnctlihil$ys!\irnfJtis ;~i*i~. tii~i.}lI.¢li il~¢te6 wlll be in,!lI.deil ill an .pperl$$"'~ ' SE,i!.;:)\S~ .' ?;,'W!\l~~ ' is cxpectl:lhob
!l" R
Deflecti on amplifi cation fac tor Paramelers used for determining approximate fundament al period Syslem ovcrstrcngth factor
the
R es ponse mod ificatio n coeffi cient
National Structural Code of the Philippines 6" Edition Volume 1
:',,,
!;- i 88
CHAP TER 5 - Steel and Metals
Basic Seismi c Load Resisting Sys tem
Response Modification Coefficient R
System Ovcrslrcngth Factor
no
Deflecti on Amplification Factor Cd
B&C (Zone 2)
Bucking- Restrained Braced Frames, nOIl -
Design Coefficients and Factors for basic Seismic Load Resi sting Systems From (AISC)
Associ ation of Stru ctural En 9ine8fS of t!18 Philippines
D
E
F
(Zone 4)
(Zone 4)
B·4. QUALIFYING CYCLIC TESTS OF BEAM·TO·COLUMN AND LINK· TO·COLUMN CONNECTIONS B-4.1 Scope This appendix includes requirements for qualifying cyclic tests of bcam-to-column moment connections in special and intermediate moment frames and link-la-column connections in eccentrically braced frames, when required
in these Provisions. The purpose of the testing described in this appendix is to provide evidence that a beam-la-column connection or a link-to-column connection satisfies the requirements for strength and interstory drift angle or link rotation angle in these Provisions. Alternative testing requirements arc permitted when approved by the cnginccrof-record and the authority having jurisdiction. This appendix provides minimum recommendations for simplified test conditions.
mcmbers and connection clements. For bea!lHO~colul11n moment connections in special and intermediate moment frames, inelastic rotation is computed based upon the assumption that inelastic action is concentrated at a single point located at the intersection of the centerline of the beam with the centerline of the column. For link~to-colul11n connections in eccentrically braced frames, inelastic rotation shall be computed based upon the assumption that inelastic action is concentrated at a single point located at the intersection of the centerline of the link with the face of the column. Prototype. The connections, member sizes, steel properties, and other design, detailing, and construction fcatures to be used in the actual building frame. Test specimen. A portion of a frame used for laboratory testing, intended to model the prototype. Test setup. The supporting fixtures, loading equipment, and lateral bracing used to support and load the test specimen. Test subassemblage. The combination of the test specimen and pertinent portions of the test setup.
Values of Approximate Period Parameters from (AISC)
Totallink rotation angle. The relative displacement of one end of the link with respect to the other end (measured transverse to the longitudinal axis of the un deformed link), divided by the link length. The total link rotation angle shall include both clastic and inelastic components of deformation of tbe link and the members attached to the link ends.
B-4.2 Symbols The numbers in parentheses after the definition of a symbol refers to the Section number in which the symbol is first used.
B-4.4 Test Subassemblage Requirements
()
Interstory drift angle (Section 13-4.6)
The test subassemblage shall replicate as closely as is practical the conditions that will occur in the prototype during earthquake loading. The test subassemblage shall include the following features:
y total
Total link rotation angle (Section B-4.6)
1.
The test specimen shall consist of at least a single column with beams or links attached to one or bon1 sides of the column.
2.
Poims of inflection in the test assemblage shall coincide approximately with the anticipated points of inflection in the Prototype under earthquake loading.
3.
Lateral bracing of the test subassemblage is pennilted ncar load application or reaction points as needed to provide lateral stability of the test subassembJage. Additional latcral bracing oj' (he test subasscmblage is not pcrmitted. unless il replicatC's lateral bracing 10 be used in thc prototype.
B-4.3 Def1nitions Complete loading cycle. A cycle of rotation taken from zero force to zero force, including one positive and one negative peak. Intcrstory drift angle. story height, radians.
Interstory displacement divided by
Inelastic rotation. The pcrmancnt or plastic portion or the rotation angle between a beam and the column or between a link and the column of [he lest specimen. measured in radians. The inclastic rotation shall be computed based on an analysis of test specimcn deformations. Sources of inelastic rotation include yielding of members. yielding or connection elements and connectors, and slip between
B-4.S Essential Test Variables The. test specimen shall replicate as closely as is practical the pertinent design. detailing. construction features. and
material properties of the prototype, The fol!owing variables shall be replicated in the test specimen.
I.
The yield stress shall be determined by materi~d tests OJ] the actual materials used for the lest specimen, as specified in Section B-4.8. The use of yield stress values that are reported on certified mill test reports arc not permitted to be llsed for purposes of this Section.
2.
The yield stress of the beam shall not be more than J.') percent below RyF)" for the grade of steel to be used for the corresponding clements of the prototype. Columns and connection elements with a tested yield stress shall not be more than 15 percent above or below R.J~~\" for the grade of steel to be used for the corresponding clements of the prototype. R.J'y shall be determined in accordance with Section 519.2.
B-4.S.1 Sources of Inelastic Rotation Inelastic rotation shall be developed in the test specimen by inelastic action in the same members and connection clements as anticipated in the prototype (in other words, in the beam or link, in the column panel zone, in the column outside of the panel zone, or in connection clements) within the limits described below. The percentage of the total inelastic rotation in the test specimen that is developed in each member or connection clement shall be within 25 percent of the anticipated percentage of the total inelastic rotation in the prototype that is developed in the corresponding member or connection element.
Jl-4.5.6 Welds
3-4.5.2 Size of Members
Welds on the test specimen shall satisfy the following requirements:
The size of the beam or link used in the test specimen shall be within the following limits:
I.
Welding shall be performed in strict conformance with Welding Procedure Specifications (WPS) as required in AWS D 1.1. The WPS essential variables shall meet the requirements in AWS D1.l and shall be within the parameters established by the filler-metal manufacturer. The tensile strength of the welds llsed in the tested assembly and the Charpy V-Notch (CVN) toughness used in the tested assembly shall be determined by material tests as specified in Section B-4.8.3. The use of tensile strength and CVN toughness values that arc reported on the manufacturer's typical certificate of conformance is not permitted to be used for purposes of this section, unless the report includes results specific to Section B-7 requirements.
2.
The specified minimum tensile strength of the filler metal llsed for the test specimen shall be the same as that to be used for the corresponding prototype \velds. The tested tensile strength of the test specimen weld shall not be more than 125 MPa above the tensile strength classification of the filler metal specification specified for the prototype.
3.
The specified minimum CVN toughness of the filler metal used for the test specimen shall not exceed the specified minimum CVN toughness of the filler metal to be used for the corresponding prototype weJds. The tested CVN toughness of the test specimen weld shall not be more than 50 percent, nor 34 kJ, whichever is greater, above the minimum CVN toughness that will be specified for the prototype.
4.
The welding positions llsed to make the welds on the test specimen shall be the same as those to be used for the prototype welds.
5.
Details of weld backing, weld tabs, access holes, and similar items llsed for the test specimen welds shall be the same as those to be used for the corresponding prototype welds. Weld backing and weld tabs shall not
1.
The depth of the test beam or link shall be no less than 90 percent of the depth of the prototype beam or link.
2.
The weight per foot of the test beam or link shall be no less than 75 percent of the weight per foot of the prototype beam or link,
The size of the column llsed in the test specimen shall properly represent the inelastic action in the column, as per the requirements in Section B-4,5.1. In addition, the depth of the test column shall be no less than 90 percent of the depth of the prototype column. Extrapolation beyond the limitations stated in this Section shall be permitted subject to qualified peer review and approval by the authority having jurisdiction.
Jl-4.5.3 Connection Details The connection details used in the test specimen shall represent the prototype connection details as closely as possible. The connection clements used in the test specimen shall be a full-scale representation of the connection elemellls used in the prototype, for the member sizes being tested.
3-4.5.4 Continuity Plates The size and connection details of continuity plates used in the test specimen shall be proportioned to match the size and connection details of continuity plates used in the prototype connection as closely as possible.
3-4.5.5 Material Strength The following additional requirements shall be satisfied for each member or connection element of the test specimen that supplies inelastic rotation by yielding:
/I,ssociation of Structural Engineers of the Pililippines
CHAPTEH 5
be removed from the tes t specimen welds unless the correspondi ng wel d back-ing and weld tabs arc remo ved from the prototype welds,
e= 0.00375 rad
6 cycles at
2.
6 cycles at 0 = 0.005 md
3.
6 cydes at 0 =0.0075 rad
4.
4 cycles at 0 = 0.01 rad
B-4.S.7 Bolts
5.
2 cycles at 0 = 0.Ol 5 rad
T he boiled po rt ions of the test speci men shall rep licate the bolted porlions of the prototype conncction as closely as possible. Add itionally, bolted portions of the lest spec imen shal l satisfy the fo ll owing req ui rement s:
6.
2 cycles at 0 = 0.02 rae!
7.
2 cycles at 0 = 0.03 rad
8.
2 cycles at 0 = 0.04 rad
Methods of inspection and nondestructive testi ng and standards of accept ance used fo r test spec imen welds sha ll be the same as those to be used for the prototype
we lds.
1.
T he boll grade (for exa mple, ASTM A325, A325M, AST M A490, A490M. AS TM F1852) used in the test specimen shall be the same as that to be used for the prototype, except that ASTM A325 bolts may be substituted for ASTM F 1852 ho lts, and vice vcrsa.
2.
T he type and orien tation o f boll holes (standard , overs ize, shOll slot, long s lot, or other) used in the test specimen shall be the same as th ose to be lI sed for the correspondi ng bolt holes in the prototype.
3.
W hcn inelastic rotation is to be developed either by yielding or by sli p within a bolted portion of the conncction, the met hod used to make the bolt hole s (d rill ing, sub-punching and reaming, or other) in the test spec ime n shall be the sallle as that to be lIsed in fh e correspondi ng bolt holes i n the prototype.
Bolts in the tcst spec imen sh<\l1 have the same
4.
installation (pretensiolled or other) and faying surface preparati on (no specified slip res istance, C lass A or 13 slip resi stance, or other) as that to be Ll sed for the corresponding bolt s in the prototype.
Continue loading at increments of 0 = 0.01 radin n, with two cycles o f loading at each stcp.
B-4.6.3 Loading Sequence
I.
6 cyc les at fw!al = 0.00375 rad
2.
6 cycles at f tola l = 0.005 rad
3.
6 cycles at Y,o",' = 0.0075 rad
4.
6 cycles a t 110131= 0.01 rad
5.
4 cycles at Yloull = 0.0 15 rl.ld
6.
4 cycles at flOlal = 0.02 rad
7.
2 cycles at flot,ll = 0.03 m d J cycle at Ylotal
= 0.04 rad
9.
J cycle at
= 0.05 fad
11 -4 .6.1 General Req uirements
10. J cycle at f lOlal = 0.07 rad
The test specimen shal l be subjected to cyclic loads according to the require ments prescri bed in Secti on Section B-4.2 for beam-to-column moment connections in special an d interm ediate moment frames, and according to th e requi rcmcI1ls prescribed in Section Section BA.3 fo r linkto~col u l1ln con nections in eccelll rically braced frames.
II. I cycle al fto lnl = 0.09 rad
Bealll-to-Colullln
Link-to-Column
Qun li fy ing cyclic tests of link -to-co lumll mo ment connecti o ns in eccentrically braced frames shall be conducted by controll ing the total li nk rotation <.I ngle, l' total , imposed on th e test specimcil, as follows:
8.
B-4.6.2 Loading Sequ ence for Moment Connecti ons
for
C Ollnections
11-4.6 Loading History
Loadi ng sequences other th an those spec ifi ed in Sect ions Section B-4.2 and Section B-4.3 may be used when they are dc monstrated to be of equivalent or greater sever ity.
5-191
sha ll be conducted by controlli ng the interstory drift angle, 0, imposed on the test specimen, as specified below:
I.
6.
Steel and Metal
YIOI.:II
Contin ue loading at increments of YlOtal = 0.02 rad ian, with one cyc le of loadin g at each step. B 4,7 Instrumenta tio n M
Suffi cient inst ru mentation shall be prov ided on the test speci men to perm it measurement or calculat ion of the quantities listed in Seclion 8-4.9.
B-4.8 Materials Testing Requirements B 4.8. 1 Tension Testin g Requirements for S tru ctural Steel M
Quali fying cycl ic tests of bea l11 ~ t o - col lJ mn 1110 men t connecfions in special and int ermediate moment frames
Tens ion testi ng siUll! be conducted on samples of sleel ta ken from the materia l adj at.:cnl to each test specime n. Tensio n ~
!\]ationa! Structurai Code of the Philippines
6!il
Edition Volume 1
S· 192
CHAPTEn: ~i· Sleet and Metals
tes ( res ults from cCI1i llcd mill tes t reports shall he reponed hut arc not permitted to he used ill place of speci mcn testing. for the purposes o f this Section. Tension-test results shall be based upon test ing that is conducted in acco rdillH':c with
2.
cle ments, wel di ng details including fi ller mewl, the size and locati on of holl hol es, the size and grade of boils, and all other pertinent de tails of the connection.
Section B·4.8.2. Tension testing shaH be conducted and reported for th e following portions of the test specimen: I.
Flange(s)' and web(s) of bc;.:~, s and columns at standard
~.
A listing of all othcr esse nti al va riables for thc lest specimen, as listed in Section 13 -4.
4.
A listing or plot showi ng the applied load displacement hi s1.?ry of the test specimen.
5.
A listing of all dcmand critica l welds.
6.
Dcfinition of the regio n of the connection that co mprises thc protected zones.
7.
A 1'101 of the applicd load versus the di splacement of
locations·
2.
Any e lcment of thc connection that supplies inclastic
rota ti on by yielding 11-4.8.2 Methods of Tension Testing for Structural Steel Tensio n testing s hall be conducted in accordance with ASTM A6IA6M, ASTM A370. and ASTM E8, wit h the fo llowing cxccpt ion s;
I.
2.
The yield Sl ress, Fl" that is repol1cd from th e tcst shall be based upon thc· yield strength definit ion in ASTM A370, using the offset mcthod at 0.002 strain,
The use of
H~ n s il e s1reng1 h
8.
A plot of beam moment versus interstory drift angle for beam-to-column moment connccti ons; or a plot of link shcar force versus link rotation angle for link-to·· column connections. For bcall1-(Q·column connections, the beam momenl and the interstory drift angle shall be computed with respect to the centerlin e of the column.
9.
The interstory drift ang le and {he total inelastic rotation de veloped by the test specimen. The components of th e test specimen contributing to Ihc totai inelastic rotation due to yielding or sli p shall be identified. The portion of the total inelastic rotation contributed by each co mponcnt of the test specimen shall be repolled. The method used to compute inelastic rotati ons shall be clearl y shown.
and r:VN IOllghn(',ss v:l liles Ihat
are reported on the manu fac turer's typical certifi cate of conform
or
the tcst spcci mcn. TIle di splacement re ported in (his plot sha ll bc measured III or near Ihe poinl of load application . 1lle locations on the tcst spccimen where. the loads and di splace men ts werc mcasured shall be clearly indicated.
The loading ratc for the tension tcst shall replicate, as closely as practical, the loading rate to be uscd fo r th c tcs t speci men.
1l-4.8.3 Weld Metal Testing Requirem ents The tensile strength of the welds used ill the tcsted assembl y and the CV N toughness used in the tested assembl y shall be determined by l1latcri~1 tcsts as specifi ed in Section B-7.
A draw ing of Ihe connccti on dClail s howin g lilcmher sizes, grades of steel, th e si"l.-cs o f all connec tion
10. A chronological listing of significall t test observations, including observations of yielding, slip, in stability, and fracture of any porti on of the tes t specimen as applicable. II. The controlling failure mode for the test specimen. If the test is terminated prior to failure, thc reason for terminating the test shall be clearly indicated.
12. The results of the materi al tests specified in Scction B4.8.
B·4.9 Test Reporting Requirements For ei.lch lest spec imen, a written test report meeti ng Ihe requirc mcnts of the authoJit y havi ng jurisdicti on and the requirements of th is Scction shall be prepared. Thc repoll shall thoroughly document al l key features and resul ts of tile tes t. The report shall include the following in formati on: I.
1].
T he Welding Procedure Spccilic"Hi olls (W PS) and welding inspection repolls.
Additional drawings . data, and disclission of the test specim en or tes t resul ts are permitted to be included in the repo rt.
A drawing or clcar description of thc test subasscmblagc, including key dim ensions, boundary conditi ons at loading and reaction points, and location of-lateral braces. Association of Structura l Engineers of the Philippines
CHAP1Tfi 5
B~4.10
Steei8nd M(:)!.;]I
~)-19J
Accephtncc Criteria
The test specimen must satisfy the strength and interstory (li"ift angle or link rotation angle requirements of these Provisions for the special momcnt frame, intenncdj,ile momcnt frame, or eccentrically braced frame connection, as applicable. The test specimen must sustain the required interstory drift angle or link rotation angle for at least one complete loading cycle.
B-S.l Scope This appcndix includes requirements for qualifying cyclic tests of individual buckling-restrained braces and bucklingrestrained brace subassemblages, when required in these provisions. The purpose of the testing of individual braces is to provide evidence that a buckling-restrained brace satisfies the requirements for strength and inelastic deformation by these provisions; it also pcrmits the determination of maximum brace forces for design of adjoining elements. The purpose of testing of the brace subasscmblage is to provide evidence that the brace-design can satisfactorily accommodate the deformation and rotational demands associated with the design. Further, the subasscmbJagc test is intended to demonstrate that the hysteretic behavior of the brace in the subassembJagc is consistcnt with that of the individual brace elements testcd uniaxially. Alternative testing requirements arc permitted when approved by the engineer-of-record and the authority having jurisdiction. This appendix provides onJy minimum recommendations for simplified test conditions.
B-S.2 Symbols The numbers in parentheses after the definition of a symbol refers to the Section number in which the symbol is first used. ,db Deformation quantity used to cOl1trol loading of the test specimen (total brace end rotation for the subassemblage test spccimcn; total brace axial deformation for the brace test specimen) (Section £-5.6).
dbm
Value of deformation quantity, 6b, corresponding
to the design story drift (Section £-5.6).
,db)'
Value of deformation quantity, db, at significant yield of test specimen (Section £-5.6).
National Structural Code of the Philippines 6'" Edition Volume 1
first
5.
The calculatcd margins of safety for the prototype conncction design, steel core projection stability, overall buckling and other relevant subasscmb!agc test si)cciJ}1en brace construction details, excluding the gusset plate, for the prototype, shall equal or exceed those of the subasscmblage test specimen construction.
6.
Latera! bracing of the subassemblage test specimen shall replicate the lateral bracing in the prototype.
7.
The brace {Cst specimen and the prototype shan be manufactured in accordance with the same quality control and assurance processes and procedures.
B-S.3 Definitions BRACE TEST SPECIMEN. A single buckling-restrained brace clemen! llsed for laboratory testing intended to model the brace jn the Prototype.
DESIGN METHODOLOGY. A set or step-by-step procedures, based on calculation or experiment, used to
determine siles, lengths, and details in the design of buckling-restrained braces and their connections.
INELASTIC DEFORMATION. The permanent nr plastic portion of the axial displ<.lccmcnt in a buckling-restrained brace.
Extrapolation beyond the limitations stated ill this section shall be permitted subject to qualified peer review and approval by thc authority having jurisdiction.
PROTOTYPE. The brace. connections. members, steel propcl1ics, and other design, detailing, and construction features to be used inlhe actual building frame.
SUBASSEMBLAGE TEST SPECIMEN. The combination of the brace, the connections and [esling apparatus that replicate as dosely as practical the axial and flexural deformations of the brace in the prototype. TEST SPECIMEN. Brace test specimen or subassembJage test specimen. B~5.4
Brace Test Specimen The bracc test specimen shall replicate as closely as is practical the peninelH design, detailing, construction features, and material properties of the prototype. B~S.5
B-S.S.l Design of Brace Test Specimen The sallle documented design methodology shall be used for the brace (cst specimen and the prototype. The dcsirr: calculations shall demonstrate, at a minimum, the followin;: req ui rcments:
Subassemblage Test Specimen The subassembJage test specimen shaH satisfy the following requirements:
I.
The calculated margin of safety for stability again::: overall buckling for the prototype shall equal or exceed that of the brace test specimen.
The mechanism for accommodating inelastic rotation in the subassemblagc test specimen brace shall be the same as that of the prototype. The rotational
2.
The calculated margins of safety for the brace test specimen and the prototype shall account for differences in material propeI1ies, including yield ;m' i ultimate stress, ultimate elongation, and toughness.
1.
deformation demands on the subassembJage test specimen brace shaH be equal to or greater than those of the prototype.
2.
3.
4.
The axial yield strength of the steel core, Pl'sn of the brace in the subassemblage test specimen sh'all not be less than that of the prototype where both strengths are based on the core area, Asp multiplied by the yield strength as determined from a coupon test. The cross~sectional shape and orient
B~S.S.2
Manufacture of Brace Test Specimen
The brace test specimen and the prototype shall be manufactured in accordance with the same quality contn:·) and assurance processes and procedures. B~S.S.3 Similarity of Brace Test Specimen and Prototype
The brace test requircmcnts:
specimen
shall
meet
thc
follo\\<11.:'
J.
The cross-sectional shape and orientation of the steel core shall be the sanie as thaI orthe prototype.
2.
The axial yield strength of the steel core, 1\,(,> o( braee test specimen shal! not vary by !llor~ {h~" percent from that of the prototype where both strenglils arc based on the core area, A.ln multiplied by tbe yield strength as determined from a coupon test.
Association of Structural Engineers of the Philippines
1
The material 1'01', and mcthod of. separation between the stec/ core ill1d the. buckling restrainin g mechanism in the brace test Spct..:lll1cn shall be thc sa me as tha t in I he prototype.
Ex trapolation beyond th e limitations staled in th is section be pcnnittcd subject to qualifi ed peer review and Clpproval by the authori ty havingjurisdictioll . .~ha ll
U·S.S.4 Conned ion Details The connection detail s lIsed in the bmcc Icst specimcn sha ll represent the prototype connection details ns closciy as pmcl iea l.
be applied and maintained as the protocol is folloWL!d for axial deformation.
B-S.(•. 3 Loading SC(llICIl('(' Loads shall be applied to the test speci men 10 produ(;c the following deformations, where the deformation is Ih l~ steel core. axial deformation for the {cst specimen ilnd the rOlational deformation dema nd for the subassclllblagc test specimcn brace: I.
2.
2 cydes of loading at the ucformation correspondi ng to lib = IIby • 2 cycles or IOilding = 0.50<111111
CIt
the deformation corres ponding 10
<111
U·S.5.5 Materials I.
Steel core: The following requireme nts shall be sat isfied for the stee! core of the brace test specimen:
n,
The specified minimum yield st ress of the brace lest specimcn steel (;orc shall be the senne as th aI or the
prototype. b.
The measured yield stress of the material of thc steel core in the brace lest spec imen shall be at least 90 percent of that of the prototype as det ermined from coupon tests.
c.
The specified minimulII ultimate stress and strain or the brace test specimen stee) core sha ll not exceed those of Ihe protolype.
2.
Buckling-res training mechanism Materials used in the buckling-restraining mechanism of the brace test spec imen shall be th e same as those
used in the prototype.
11·5.5.6 Connections The welded, bolted, and pinned joints on the tcst speci men shall replicate {hose 011 the prolOlype as c10sc as practi cal. 11·5.6 Loading History
B-S.6.1 General Require ments The test specimen shall be subjected to cyc lic loads accord ing to the req uire ments presc ri bcd in Secti ons D5.6.2 and 8-5.6.3. Addit ional increments or loading beyond th ose desc ribed in Section 13-56.3 arc pennillcd. Each cycle shall include a full tensi on and full compression excursion 10 th e prescribed deformation.
Il·S.6.2 Test Control
3.
2 cycles of loading at the deformation corresponding to lib = 11111111
4.
2 cycles of loading .db = 1.5.dbm
5.
2 cycles of loadi ng at the dcrOrinaliol1 correspondi ng to .db = 2.0.dbm
6.
Additional complete cycles of loading Ut the deformation cOITespondillg 10 db::::: 1.5/.Jbm as required for th e brace test speci men 10 achieve a cumu lative inelastic axial deformation of (\( !east 200 times the yield deformation (not required ror the subasscmblage lest spec imen ).
at
th e deforma tion corresponding
to
The design story drin shall no t be ta ken as less th an 0.0 1 times the story height ror th e purposes or calculating /.fbI/I. Other loading sequences are permitted to be used to qualify the tcst specimen when th ey are demonstrated to be or equa l or grea ter severity in terms of' maxi muIll and cUlllulat ive inelastic deformation. Il-S.7 Instrumentation Sufficient instnlmentati on shall be provided on the test specimen to permit measurement or calculation of the quantities listed in Section I3~5.9.
D-S.S Materials Testing Requirements 8·5.8.1 Tension Testin g Requirements Tens ion testing shall be cond ucted on samples of steel taken rrom the same material as that lIsed to manuraclure the steel core. Tension test results from cenified mill test repo rt s shall be reported but arc not permitted to be used in place oj' specimen testing for the purposes of this Section. TCIl Sio lltest resul ts shall be based upon testing that is conducted in accordance with Section B~5,8.2.
The test shall be condu cted by cont rolling the level or axiCli or rotati onal deformation, LIb, imposed on Ihe lest speci men. As an alternate, th e maximum rotational deformati on may
National Structural Code of the Philippines 6
th
Edition Volume 1
~) · 19G
CHAP1TFl5· Stet;i ancJ Met als
B·s.8.2 Methods of Tension Testing Tension iCsting shall be C(lIH.lucted ill accordance wilh ASTM A6, ASTM A37(), and ASTM EH, with th e lollnwing
Add itional drawings, data, and discussio n or the test speci men or test results arc pcrmillcd (0 be inclu(k~d in the rcpol1.
exceptions: I.
The yield st ress Ihm is reponed from the test shall he based upon the yield stre ngth definition in ASTM A370, lIsing th e olTset method of 0.002 strain.
2.
The Joadiq; !·atc for the (cl)sion lest shall repliciUc, as closcly as is practical, th e IO}lding ratc L1sed for the test specimen.
3,
The coupon shall be machined so thai its longitudinal axis is parallel to the longitlldinal axis of the stcel core.
H-S.9 Test Reporting Requirements For each tcst specimen, a written test rcp0l1 mce.ting th e requ irements of thi s Section shall be prepared. The rcpol1 shall thorough Iy docu melll all key fea lUres and resul ts of the test. The repO[1 shall include the following information:
J.
2.
A drawing or clear descriptioll of' the lest speci mell , including key di mensions, bou nd ary cond itions al loadin g and reactioll points, and location of lateral bracing, if any. A drawing of the connection delHi ls showing member sizes, grades of steel. th e sizes of all con necti on clements, weldin g details including tiller metal, the size and location of bolt or pin holes. the size and grade of co nnectors, and all other peninent details of the connections.
3.
A listin g of all other essential varinbles as listed in Section B-5.4 or 3-5,5, as appropriate.
4.
A listing or plot showing the applied load or displacement hi slory.
5.
A plot of the appli ed load versus the deform ation, 6.b. The method used to delennine the deformations shall be clearly s hown . The locations on the lest specimen where the loads and deformations were measured shall
Acccpt~lncc Criteria Icast olle subassem blagc test til al sati sfies th e requi re ments 0(" Section 8·5.4 shall be performed. At least one brace lest that satisfies the requirements of Section B· 4.5 shall be performcd. Within the requ ired protocol ran ge all tcsts shall satisfy the following requirem ents:'
B·S. I ()
At
I.
" The plot showing the applied load vs. displ llccmcllt history shall exh ibi t stable. repe
2.
There shall be no fracture. brace in ~tabil i ty or brace end connection failure .
3.
For brace tests, each cycle to a deform ation greatcr than !.1by the maximum tension and compression fortes shall not be less than the n omi n ~1 stre ngth of the core.
4.
F~'o r brace tests, each cycle to a deformation greater than /.Jby the ratio of the maxim um com press ion force to the
maximum tension force shall not exceed 1.3. Other acceptance criteria may be adopted for the brace test speci men or subasse mbl age test specimen subject to qualified peer reyiew and appro val by the authority hav ing juris~~ction.
......
be clearly identifi ed,
6.
A chronological listing of sign ificant test observations, including observations of yielding, slip, instability, transverse displacement along the tesl specimen and fraclure of any portion of the test specimen and co nnecti ons, as app licable.
7.
The results of th e material tests specified in Section U5,8,
8.
The manufacturing qu ality control and quality ass uran ce plans used for the fabricati on of tbe lest specimen. These shall be included with the welding procedure specifications and welding inspection reports,
Association of Structural Engineers of the Philippines
.. '
B-6.2.3 Erection Dnlwings Ercc!ioll drawings shall
B-6.1 Scope
foll owing in formation:
This ap pe ndi x provides addi tiona l d ew il s regardi ng we ld ing
I.
and welding inspection, and is included on an interim basis pendin g adoption of such critcriu by A WS or ot her
2.
Structural Design Drawings .wd Speciflcatiuns, Shop 'D rawings, and Erection Drawings /1·6.2. 1 Structural Specifications
Design
l)rawings
J.
Location s where backup bars arc req uired removed
2.
Locations where supplemental fill ct weld s arc req uired whe n backing is pCfm ill cd 10 remai n
3.
Loca tion s where fillet wel ds arc used
10
(0
be
reinfo rce
a minimum. the
Locati ons where backing bar.-; to be removed Loca!ions where su pplemental lWets arc required when
3,
Loca ti ons where weld hlbs are to be rem oved
4.
Those joints or groups of joints in whi ch ;" sl.'.cdfic asse mbl y order, welding sequ ence. welding tech niqu e or other special precau tions arc re4ui rcd
and
Stru ctunll design dra wings
backing is penn ilied to remain
acc redi ted org.\I\iZell ioll . n~6.2
inclu de .
B·6.3 Personnel B-6.3.1 QC Welding Inspectors QC weld ing inspection personnel shall be associate welding ins peclOfs (A WI) or high cr; ~ as defined ill A WS 85.1 Standard fo r thc Qualificati on of Welding Inspectors, or ot herwise qua lified undcr the provisions of A WS 01. 1 Secti on 6. i.4 and to tile satisfaction of the con tractor's QC plan by the fabricator/erector.
groove welds or 10 improve con necti on geometry 4.
Loca tion s where wel d ta bs are required to be rem oved
5.
Spl ice locations where ta pered tran sitions are req uired
Us¢r Ni1tC':Butt spIi~ SUbjeCt tp [eliSion greatenh"" 33 pe¥C~iit ohii'e' ~itPi!i;\\!d 'y;,iM " tte"ngih · iinder ' anY ':ldad
ti~!~m!t:D1~o2i~~~~~;!tf~~s·:t:;iffff.~· ii~'~tr;o~
cofu¢r.d>pld cause\~ yi&\ding~heilllie tehSlle. siYess excee;i~ :)3p.,tcentoYYiddI.6wet levels of ~tfess would be accepta~Ic w'i"ih the ~StiiSs· concentration from a non tapered transition.
B-6.3.2 QA Welding Insp ecto rs QA welding inspectors shall be welding inspcc tors (WI), or senior we lding inspectors (SW I). as de li ned in A WS B5.1, except AWls may be used under thc direct supervision of WIs, 0 11 si te and available when weld inspection is being co nducted.
B·6.3.3 Nondestructive Testing Technicians NDT techni cians shall bc qu alifi ed as follows: I.
. sha l ~
6.
The shape of we ld access holes, if a special required
7.
Joints or gro ups of joints in which a specific assembly order, welding sequence, wclding tcch ni que or othcr special precautions are required
Society for Non destructive Testing, Inc. SNT TC-I A Recommended Practice for the Training and Testin g of Nondestru ctive Personnel, or of ANSIIASNT CP- 189, Standard for the Qualification and Certification of Nondestructi ve Testin g Personnel.
is
2.
Ul trason ic testin g for QA may be performed only by UT tcch nicians certified as ASNT Level III through examin ati on by the ASNT, or certified as Levcl II by their employer for flaw detection. If tile engineer-ofrecord approves the use of fl aw siz.i ng techni ques, UT technici ans shall also be qualifi ed and certified by their em ployer for fla w sizing.
3,
Mag neti c p,utide tes ting (MT) and dye penetrant testing (PT) for QA Illay be perforilled only by technicians certifi ed as Level 11 by their e mployer, or certified as AS NT Level III throu gh examination by th e ASNT and certified by th eir employer.
B-6.2.2 Shop Drawings S hop drawin gs shall incl ude, as a minimum , the foll ol,l,.'ing informat ion: I.
Access hole dim ensions , surface profi le and fini sh requirements
2.
Locations where backing bars are to be removed
3.
Locm iolls where we ld tabs arc to be removed
4.
NOT to be pcrfotrned by the fabri cator. if any
In accordance with their employer's writte n practi ce which shal l mcet or exceed the critcria of the American
u National S tructural Code of the Philippines 6 , Edition Volume 1
!j· 19B
CHAPH:11 S . Steel iln
B-6.4 Nondestructive Testing Procedures
III. The steel used for the qualification testing shall same type and grade as will be llscd in production.
!)l'. of
the
U-6.4.1 Ultrasonic Testing Ultrasonic test ing s hall he performed accordi ng 10 the procedures prescrihed in A WS D 1.1 Sect ion 6, Pan F following a written procedure containing thc clements
prescribed in paragraph K3 of Annex K. Section 6, Part F procedures shall be qualified using wcld mock-ups having 1.5 mlll-diamctcr side drilled holes similar to Annex K, Figure K-3. .' B-6.4.2 Maglletic Pm·tiele Testing Magnetic particle testing shall be performed {lceording to procedLlrcs prescribed in A WS D 1.1 , following a wrillen procedure utili zing the Yoke Method thtH conforms 10 ASTM E709. B~6.5 Additiollal Welding Provisions
B-6.S.1 Inlermixed Filler Mettlls When rCA W-S filler metlll s arc used in cOlllbin,lIion wil h filler metals of other processes, including rCAW ·G, a test spccimen shall bc prepared and mechanical testin g shall be conducted to verify that the notch toughn ess of the combined materials in thc intermixed region of the wcld meets thc notch tough ness requ irc ments of Secti on 520.3.1 and, if req uired, the notch toughness rcquirements for demand critical welds of Section 520.3.2.
The max im ulll heal input to be used in production sha ll be used in the qunJilicatioll tesling. The qualificd Illaximum intcrpliss temperature s hall he th e lowe:.;t intcrpass temperature used for any pass during qualijicatioll testing.
Both weld melal and HAZ shall be tested. The weld meta! ':l1all meet all the mechanical properties required by Section 520.3.1, or th ose for demand cri ti cal welds or Scction 5203.2. as appli cable. The hem "ffeeled ?olle CVN toughness shall mect a minimum requircment of 27 J at 2 I °C with specimcns taken at both J and 5 mm from the. fusion line. B·6.5.5 Weld Tabs Where practicable, weld tabs shall extend beyond the edge of the joint a minimulll of olle inch or the thi ckness of the par!, ~hichever is greater. ExtensiDns need not exceed SO 1l1111.
Where used, weld labs shall be rcmoved to wi th in 3 illJll of the base metal surface, except at continuity plates where rcmoval to with in 6 !llmof th e plate edge is acceptable, and thc end of the weld finished. Removal shall be by air carbon arc cutting (CAe-A), grinding, chipping, or thermal culti ng. The process sha ll be con trolled to lIlinimiz.e errant gouging. The edges where weld tabs have been removed shall be finished to a surface roughness of 13 ~ln1 or betlcr. Grinding to a flush condition is not required. The contour of the weld end shall provide iI smoo th tran sition, free of notches and sharp comers. At T-joints, a mini mum rad ius in the corner necd not be provided. The weld e nd sha ll be free of gouges and notches. Weld defects not greater than 2 nun deep shall bc faired to a slope not greater than I :5. Other weld defects shall be excavated and repaired by welding in nccord ancc with an applicable WPS.
B-6.5.2 Filler Met,,1 Diffusible Hydrogen Wclding electrodes and cicctrode· nux combinati ons shall meet the requirement s for H J6 (16 mL maximum diffusible hydrogen per 100 grams deposited weld metal ) as tested in accordance with AWS A4. 3 Standard Methods for Determination of the Diffusible Hydrogen Content of Martensitic, Bainil!c, and Fcrrit;c Steel Weld Metal Produced by Arc Welding. (ExCel'l ion: GMA W solid electrodes.) Thc manufacturer's typical certificate of conformance shall be considered adequatc proof that the supplied electrodc or electrode-flux co mbination meets this requirement. No testing of filler metal samples or of production welds shall be required.
When using weld access holes to facilitate eJP groove we lds of beam bottom flanges to column flanges or continuity plates, the groove wcld shall be sequenced as follows: .
1J-6.S.3 Gas-Shielded Welding Processes
1.
GMA Wand FCA v.,'-G shall not be performed in winds exceedi ng 5 kill/hI'. Windscreens OJ' ot her shelters may be used to shield the we ld ing operation from excess ive winci.
2.
11-6.5.6 Bottom Flange Welding Sequence
Maximum inlerpass temperatures shall not exceed 290 oc. measured at a distance not exceeding 75 rnm from the St31t of the weld pass. The maximuill illlcrpass temperature Illay be increased by qualification lc.<;ting thal includes we ld metal and base metal CVN testin g using AWS D 1. J Annex
Each la yer shall be completed across the full width e,l' (he llange before begi nni ng the next laycr.
:~.
B-6.S.4 Maximum Intcrpass Temperatures
As far as is practicable, starts and stops shall not be placed directly under the beam w('.\).
For each la yer, the weld s{(trts and stops shall be nil :h!' opposite side of the beam web, as compared to the previous layer.
Association of Structural Engineers of the Philippines
\!\i) iii·;
B-6.6 Additional Welding Provisions for Demand Critical \"('Ids Only B-6.6.1 Welding
pl'()C(~sses
SMAW, C;MAW (except short circuit transfer), FCAW and SA W may be used to fabricate and crect members governed by this specification. Other processes may be used, !Jrovidcd that onc or Jllore of tile fo!lowing criteria is me!: I.
The process is part of the prequalified conllection details, Wi listed in Section B-!,
2.
The process was used to perform a connection qualification test in accordance with Section B-4, or
3.
The process is approved by the engineer-of-record.
B-6.6.2 Filler Metal Packaging Electrodes shall be provided ill packaging Ihal limits the ability of the electrode to absorb moisture. Electrode from packaging that has been pUllctured or torn shall be dried in accordance with the manufacturer's recommendations, or shall not be used for demand critical welds. Modification or lubricatio/l of' the electrode after manufaclUre is prohibited, except that drying is permitted as recommended by the manufacturer.
B-6.6.3 Exposqre I....imitations on FCA \V Electrodes After removal from protcctive packaging, the perJnissible atmospheric exposure time of FCA W electrodes shall be limited as follows: I.
Exposure shall not exceed the electrode manufacturer's guidelines.
2.
In the absence of manufacturer's recommendations, the total accumulated exposure time for PCA '0/ electrodes shall not exceed 72 hours. When the electrodes are not in usc, they may be stored in protective packaging or a cabinet. Storage time shall not be included in the accumulated exposure time. Electrodes that have been exposed to the atmosphere for periods exceeding the above time limits shall be dried in accordance with the electrode anufaclurer's recommendations, or shall not be used for demand critical welds. The electrode manufacturer's recommendations shall include time. temperature, and number or drying cycles permitted.
B·6.6.4 Tack Welds
Tack welds attaching backing bars and weld tabs shall be placed where they will be :ncorporated into a final weld.
B·7 WELD METALIWELDING PROCEDURE SPECIFICATION NOTCH TOUGHNESS VERIFICATION TEST This appendix provides a procedure for qualifying the weld metal toughness and is included Oil an interim basis pending adoption of s!Jch a procedure by the American Welding Society (AWS) or other accredited organization. B-?.! Scope
This appendix provides a standard method for qualillcation testing of weld Illler metals required to have specified notch toughness for service in joints designated as demand critical. Testing of weld metal to be used in production shall be performed by filler metal manufacturer's production lot, as defined 1Il AWS AS.O I, Filler Metal Procurement Guidelines, as follows: I.
Class C3 for SMA W electrodes,
2.
Ciass S2 for GMA W -S and SA W electrodes,
3.
Class T4 for FCAW and GMAW-C, or
4.
Class F2 for SA W fluxes.
Filler metals produced by manufacturers audited and approved by one or more of the following agencies shall be exempt from these production lot testing requirements, provided a minimum of 3 production lots of material, as defined above, are tested in accordance with the provisions of this appendix: J.
American Bureau of Shipping (ABS),
2.
L10yds Register of Shipping,
3.
American Society of Mechanical Engineers (AS ME),
4.
ISO 9000,
5.
US Department of Defense, or
6.
A quality assurance program acceptable to the engi Heer-of-record.
Under this exemption from production lot testing, the filler metal manufacturer shall repeat the (esting prescribed in this appendix at least every three years on a random production lot.
th
National Structural Code of tile Philippines 6 Edition Volume 1
(l·7.2 Test Conditions Test s shall be conduclCd
whi ch th e weld liller met al will be qualified under the weldin g pfOt:cdurc specification (WPS). It is recommend ed that test s be co ndu cted at the low heal input level and high heat input level indicated in Table 0 ·7.2· /'
assembly has rcm.: hcd the inlcrpass temper.Hure prescribed in Table 13 -7.2- 1. The inlcrpa ss temperature shall be maimaincd for the rema inder of the weld. Should il be !letcss.lr)' 10 in terrupt weld in g, the asse mbl y sh,11J be allo wcd (0 cool in air. The assc mbl y sha ll then he heated 10 th e prescribed interp;!ss temperature befo re welding is resumed. No thermal treatm eIH or weldment or test :-.pecimcns is permitted, except that rnach!lled tensile test SpC(;!lllenS may be aged at 200 °F (93°C) io 220 °F (104°C) I,),. lip to' 4 8 hours, then cooled 10 room temperature before testin g.
Heat Input Low heat
30 klIin.
input test
( 1.2kJ/mm)
High heal input les t
80 kJlin. 1.2kJ/mm)
AhermHivcl y. Ihe filler melal manufacture r or contractor may ci cc I to test 11 wider or narrower ran ge of heat input s
and interpass temperatures. The range of heat inputs and interpass temperatures tested shall be clearly stated on the test report s and user data sheets. Regardless of the method of selecting tes t heat input, the WI'S, as used by th e contractor, sIJall fall within the ran ge of heat inputs an d interpass temperatures tested.
B·7.3 Test Specimens Two test plates, one for each heat input, shall be welded following Table 13-7.2-1. Five CVN specimens and one tensile sped men shall be prepareeJ per plate. Each plate shall be steel, of any AISC-listed structural grade. Tlw test plate shall be 19 mill thi ck with a 13 111m root opening and 45° included groove angle. The test plate ~lId specimens shall be as shown in Figure 2A in A WS A5 .20, or as ill Figure 5 in AWS A5.29. Except for the root pass, a minimum of two passes per layer shall be used to fill th e width.
B-7.4 Acceptance Criteria The lowest and hi ghes t Charpy V-Notch (CVN) toughness values obtained from the five specimens from a single test plate shall be di sregarded. Two of the remaining three values shall equal , or exceed, the specified toughn ess of 54 J energy le vel at the tesl ing temperature. One or Ihe three ma y be lower, but not lower than 41 J, and Ihe average of the three shall not he less than the required 54 J energy level. All tcst sam ples shall meet the Jl otch toughness requirements ror th e electrodes as prov ided in Section 520.3.2. For filler metals classi fi ed as E70, materi als shall provide a minimum yield stress of 58 ksi , a minimu m tensile st rength of 70 ksi , and a minim ulll elongation of 22 percellt. For filler metals cl ass ified as E80, materi als shall pro vide a minimum yiel d stress of 68 ks i, a minimum tensile strength of 80 ksi, and a min imum elongation of 19 percent.
All test specimens shall be taken from near the centerline of the weld at the mi d-thickness lo cati on, in ord er to minimi ze dilution e ffects. CVN and ten sile specimens shall be prepared in accordance with AWS B4 .0, SHindard Methods fo r Mechanical Testing of Welds . The ICst assembl y sllall be restrained durin g we ld ing, or preset at approximatel y 5° 10 prevcnt warpn ge in excc;;:) of 5°. A welded Icst assembl y that has warped more than 5° shall be di scarded. Weld ed (cst assembli es shall not be straightened.
The lesl asse mbly shall be l
j.l"ssociation of Structural Engineers of the Phili ppines
transfer load 10 an d bc tween clements of the seismic load resistin g system.
COMPOSITE SPECIAL CONCENTHICALLY BHACED FRAME (e-CBF). Composi le braced fraille mee ting th e req uirements of Section 543.
BOUNDARY MEMB ER. Portion along wa ll and diaphragm edge strengt hened with slj"uclural steel sections and/or longitudinal sleel reinforcement and transverse reinforcemenr. COLLECTOR ELEM ENT. Member that serves to Inll1sfer loads between floor diaphrngllls :lI1d the members of the seismic load resistin g sys tem. COMPOSITE BEAM. Structural steel bea m in contact with and actin g compositely with reinforced co ncrct(~ via
COMPOSITE SPECIAL MOMENT FRAME (C-8MF). Composite moment frame I1lcetjng tl.1c rcqu irements of Section 540. COMPOSITE STEEL PLATE SHEAR WALL (CSPW). WHI! consisting of steel pl ate with reinforced concrete encasement on one or both sides that provides OU Iof-plane stiffening to prCYCIH buckling of the steel plate and mee ting the requirements of Secti on 548. COUPLING BEAM. Structural steel or co mposite. bemll connecti ng adjacent reinforced concre te wall clements so that th ey (lct together to res ist lateral loads.
bond or shear connectors.
ENCASE!) COMPOSITE IIEAM . Composite beam COMPOSITE BRA CE. Reinforced-concrete-cncased structural sleel section (ro lled or built-up) or concrete-filled steel section used as a brace. COMPOSITE COLUMN. Reinforced-concrete-encased
comp letely c ll c loscd in reinforced concrete.
ENCASE!) COMPOSITE COLUMN. Structural steel column (rolled or built-up) completely encased in reinforced concrete.
structural s teel sec tio n (ro ll ed o r huilt -up) or co ncretc-fi ll ed
steel secti on used as a columll. COMPOSITE ECCENTRICALLY BRACED FRAME (CREDF). Composite braced frame meeting the
FACE IIEARING PLATES. Stiffeners a[[ached to structural sleel beams that arc embedded in reinforced concrete wa lls or colum ns. The plates are located at Ihe face of the reinforced concrete 10 provide confinement and to
require men ts of Section 545.
transfer londs to the concrete th rough direct bearing.
COMPOS ITE INTERM EDIATE MOMENT FRAM E Co mposite moment framc meeting the requirements of Scction 54 I .
FILLED COMPOSITE COLUMN. Roun,! or rectangu lar structural steel section fill ed with concrete.
(C~IMF).
COMPOSITE ORDINARY BRACED FRAME (COBF). Composite braced frame meeting the requirements of Section 544 . . COMPOSITE ORDINAHY MOMENT FRAME (COMF). Co mposite moment fra me meeting the requirements of Section 545. COMPOSITE PAHTIALLY HESTHAIN ED MOMENT FnAME (C·PRMF). Composite lllomen t frame meeting {he requ ire ments of Seclion 539. COMPOSITE SHEAH WALL. Reinforced conc rete wall that has uncilcased or rcinforced ~co ncrete,cncased structural steel sections as boundary members.
FULLY COMPOSITE IIEAM. Composite beam that has a sufficient number of shear conllectors to develop the nominal plastic flexural strength of the composite secti on, INTERM EDIATE SEISMIC SYSTEMS. Sei smi c sys tems designed assumin g moderate inelastic action occurs in some mem bers under the des ign earthquake. REINFORCEMENT. LOAD-CARRYING Reinforcemen t in composi te mcmbers designed and detailed to resist th e required !oil(b.
ORDINARY REINFOR CED CONCRETE SHEAR W ALL WITH STRUCTURAL STEEL ELEMENTS (CORC'V). Co mposite shear walls meeting the requirem ents of Section 546.
COMPOSITE SLAB. Concrete slab suppOIted on and bonded to a formed steel deck Ihat acls as a diaphragm to 111
National Structural Code of the Philippines 6 Edition Volume 1
ORDINARY SEISMIC SYSTEMS. Seismic systems de_signed assllming limited inelastic action occurs in some
members under the design earthquake.
PARTIALLY
COMPOSITE
BEAM.
Unencascd
composite beam with a nominal flexural strength controlled by the strength of the shear stud COllllectors.
PARTIALLY
RESTRAINED
C0MPOSITE
CONNECTION. Plll1ially restrained (PR) C01l!Icctions as defined ill the Specification that connect partially or fully composite beams to stee! columns with flexural resistance provided by a force couple achieved with steel reinforcement in the slab and a steel scal angle or similar connection at the bottom flange.
REINFORCIm·CONCRETE-ENCASED
SHAPES.
Structural steel sections encased in reinforced concrete.
RESTRAINING BARS. Steel reinforcement in composite members that is not designed 10 carry required loads, but is provided to facilitate the erection of other steel reinforcement and to provide anchorage for stirrups or tics. Generally, such reinforcement is not spliced to be continuous.
SPECIAL REINFORCED CONCRETE SHEAR WALLS COMPOSITE WITH STRUCTURAL STEEL ELEMENTS (C-SRCW). Composite shear walls meeting the requirements of Section 547. SPECIAL SEISMIC SYSTEMS. Seismic systems designed assuming significant inelastic action occurs In some members under the design earthquake. UNENCASED COMPOSITE BEAM. Composite beam wherein the steel section is not completely enclosed in reinforced concrete and relies on mechanical connectors for composite action with a reinforced slab or slab on metal deck.
SECTION 532 SCOPE These Provisions shall govern the design, fabrication, and erection of composit9 structural steel and reinforced concrete members and connections in the seismic load resisting systems (Sl.. .RS) in buildings and other structures, where other structures are defined as those designed, fabricated, and erected jn a manner similar to buildings, with buJjding~like vertical and lateral load-resisting systems. These provisions shall apply when the seismic response modification coefficient, R, (as specified in the NSCP code) is taken greater than 3. When the seismic response modification coefficient, R, i··: taken as 3 or less, the structure is not required to satis! these provisions unless required by the NSCP codc. The requirements of Pall 2B modify and supplement tk' requirements of Part 2A and form these Provisions. Thev shall be applied in conjuJ1c tion with the AISC Specificalio;l for Structural Steel Buildings, ANSIIAISC 360, hereinaf"i" referred to as the Specification. The applicable requiremCiii:i of the Building Code Requirements for Structural Concl"u' and Commentary, ACI 318, as modified in these Provisio'o'-; shall be used for the design of reinforced concre!.· componcnts in composite SLRS. For seismic load resisting systems incorporating reinforce': concrete components designed according to ACI 318, (ii': requirements for load and resistance factor design specified in Section 502.3 of the Specification shall be used.
When the design is based upon elastic analysis, the stiffnl'! propeJlies of the component members of composite systCi:" shall reflect their condition at the onset of signific,IL', yielding of the structure. Wherever these Provisions refer to the NSCP code and the"" is no local building code, the loads, load cornbina!i{;:;. system limitations and general design requireI~ents shall i,:.; those in SEllASCE 7. Pail 2B includes a Glossary which is specifically applic: . to this Pall. The Part 2A Glossary is also applicable to j 'i": 2B.
Association of Structural Engineers of the Philippines
CHAPTEn ~)
The documcnl s refercnced in Ihese provisions shilll include Ihose lislcd in P'1!1 2A Sceli oll 5 J 5 with the follo wing mlditions: American Socicl y or Civil Enginccn; .Standard for thc Structural Design of Composite Slabs, ASCE 3-91 American Welding Sociely Structural Welding CodeReinforcing Steel, AWS D 1.4 -98 ':
Steel nn(j Ivletal
[)·203
The required strength and olher I>J"{)visions for seismi c de sign catego ries (SDCs) and seismic usc groups and the limitations on height and irregularity shall be as specificd in the NSCP code. The design story drift and story drift limits shall be determined as requircd jn the NSCP code.
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Nolional Siruciural Code of the Philippines 6 'h Edition Volume 1
:)-204
CHAPT[H 5 . Sleel and Metals
535.1 Loads and Load Combinations Where amplified seismic loads are required by these Provisions, the horizontal portion of the e
ovcrstrcngth fac tor Do prescribed by the NSCP code. For the seismic IO
536.1 Structural Steel Structural steel members and connections used in composite seismic load resisting systems (SLRS) shall meet the requirements of Specification Section 501.3. Structural steel used in the composite SLRS dC'~cribcd in Sections 539,540, 543, 545, 547 and 548 shall also meet the requirements in Pa.1 2A Sections 5 19 and 520. 536.2 Concrete and Steel Reinforcement Concrete and steel reinforcement used in composite components in composite SLRS shall meet the requirements of ACI 318. Sections 21.2.4 through 21.2.8.
Exception:
535.2 Nominal Strength The nominal strength of systems, members, and connections shall be determined in accordance with the requirements of the Specification, except as modified throughout these Provisions.
Concrete and .\"led rdnjorcement used ill the composife ordillary seismic sysfems described ill Sections 542, 544. (lnd 546 shall meel lh e requiremen ls o[Secfioll 509 {llld AC/ 318. 21.
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Association of Structural Engineers of the Philippine s
CHAPTEfi 5
St r:::cl an d Metal
~i·2 0:)
537.4 .2.
537.1 Scope The design of composite members in the SLRS described in
2.
The con trihuti on of ,the reinforced·concrete-encased shape to the strength of the colulllll as provided in AC I 3 18.
3.
The seismic requirement s for reinforced concrete columns as speci fied in the descript ion of the composi te seism ic systems in Secti ons 539 through 548.
Sec tions 539 throu gh 548 shall meet the require ments of Ihis Section and th e Jll
537.2 Composite Floor and Roof Slabs The desi gn of composite flo or and roof slabs shall meet the requirements of ASCE 3. Composite sla b diaphragms shall meet th e requirement s in thi s Section .
537.2.1 Load Transfer
537.4.1 Ordinary Seismic Syslem Requirements The followin g requirements for encased com posi te columns are applicab le to all composite systems, including ordin ary seism ic systems:
I.
The available shear strength of the co lumn shall be determined in accordance with Specification Section 509.2.1 .1d. The nOr'ninal shear strength of the ti e. reinforcement shall be determined in accordance with ACI 3 18 Secti ons 11.5 .6.2 through 11.5.6.9. In ACI 318 Sections 11.5.6.5 and 11.5 .6.9, the dimension bw shall equal the width of the conc rete cross -section minus the width of the slIl1ctura l shape measured perpendicular to the directi on of shear.
2.
Composite colum n!; designed to share the appli ed load s between the stl11c tural steel section and the reinforced co ncrete encascmem shall have shear connectors th at meet the requirements of Specification Section 509.2.1.
3.
TIle maxi mum spaci ng of transverse tics shall meet the requirements of Specificat ion Sect ion 509.2.1.
Details shall be des igned so as 10 transfer loads between Lhe di aphragm and boundary members, collector clements, and clements of the hori zomai framing system.
537.2.2 Nominal Shear Strength The nominal shear strength of composite diaphragms and concrete-filled steel deck diaphragms shall be taken as the nom inal shear stre ngt h of the reinforced conc rete above the top of th e steel deck ribs in accord ance with ACI 3 18 cxcl u'ding Chapter 22. Alternatively, the composite diaphragm nominal shear strength shall be determi ned by in-plane shear [~st s of concre te-filled di aphragm s.
537.3 Composite Beams Com posite beams shall meet the require ment s o f Section 509 . Composite beams Ihat are part of compos ite-special moment frames (C-S MF) shall also mect the requirement s of Sec tion 540.3.
537.4 Encased Composite Columns Thi s sectio n is appli cable to columns th at 1.
consi st of reinforccd-concrcte encased shapes with a struclural steel area lhal comprises at least J percent of the total composite column cross section; and
2.
meet the additional li mit ati ons of Speci ficati o n Section 509.2. J. Such co lumns shat! meet the requi rements of Specification Section 509 , except as modifi ed in thi s Sec ti on. Additi ona l require me nts, as speci fied for intermediate an d specia l seismi c sys tems ill Sections 537.4.2 and 537.4 .3shall apply as required in th e descriptions of the com pos ite seismi c sys te ms in Sections 539 through 548.
Transverse ti es shall be located vertically within one-haif of the lie spac ing abo ve the top of the footin g or lowest beam or slab in an y story and shall be spaced as provided herein within one-half of the tic spacin g below the lowest beam or slab framin g into the column .
Transverse bars shall have a diameter th at is not less than one-fiftieth of the greatest side dimension of the composite member, except that lics shall not bc smaller than Diam 10Illm bars and need not be larger than Diam 16 mm bars. Alternatively, welded wire fabtic of equiva lent area is permitted as trans verse re inforcemen t except when prohibited for intermediate and special seismic systems . 4.
Load-ccHTying rein fo rcement shall meet th e detai ling and spli ce requiremcilts of ACI 318 Sections 7.8.1 and 12.17. Load-carryin g reinforcement shilll be provided at e very corn e r of (I rectangular cross-secti on. The maximum spacing o f other load carryin g or resu:ai ning longitudinal reinforcement shall be one- half of the least side dimensio ns of the compos ite member.
5.
Splices an d end bearing details for e ncased com posite co lumns in ordill ary seismic systems shall meet th e requirements of the Speciiicatio n and ACI 3 }8 Section
Colum ns that co nsi st of reinforced-concrete-en cased shapes
shall meet the requirements for re inforced concre te COIUIllIIS 0(' ACI 31 8 except as modified for I.
The st ructural steel secti on shear con nectors in Section
National Stru ctural Code of the Philippines 6 '1> Edilion Volume 1
:)·20G
CH I\P T[j ~~)
Sloe l iJnd Metals
7.X.2. The design shall comply with ACI 318 Sections 2 J .2.6, 21.2.7 and 2 1. 10. Th e design shull <':ollsi
adverse behavioral effects due to abrupt changes in either the member sti ffness or Ihe nominal tensile strength . Such locations shull include transitions to rei nfon.:cd conc rete sections without embedded structural steel members, transitions to hare structural steel sections, and column bases.
A".
The maxi mum spacing of trans verse bars at the top and bOllom shall be lhe Jeasl of lhe following:
iI.
onc-half the least dim ension of the section
b.
8 longitudinal bar diameters
c.
24 tie bar dimneters
d.
300 mOl
These spacings shall be mai ntained over a verti cal distance equal to the greatest of the following lengths, measured from each joint face and on both sides of any secti on where flexural yielding is expected to occur: 1l.
one-sixth the venical clear height of the column
b.
the maximum cross-secti onal dimension
c.
450 mm
2.
Tic spacing over lhe remaining column lengl h shall nOI exceed twice the spacing defined ab ove.
3.
Welded wire fl.lbric is not permitted as trans versc reinforcement in intermediate seismic systems.
h,.,.
I~,
A, P"
The required axi al strength for encased composite columns li nd splice det ai ls shallmcet (he req uirements in Part 2A Section 521.3.
2.
LOilgitudinal load -carrying reinforcement sllall mcet the requircments of ACI 3 18 Section 2 1.4.3.
3.
Tra nsverse reinforcement shall be hoop reinforceme nt as defined in ACI 318 Cha pler 21 and shall meel lhe foll owing requi rcmellls:
a.
The minimum area of ti e reinforcement Ash shall meet lhe following :
(&J. 537 ·1)
cros!; ~ dcc{ional dim ensi on of the co nfined corc measured cC llt er- t o~sC llt c r of the tic reinforcemen t, mm . :::; spacin g of transverse reinforcement measured along the longitudinal axis of the structu ra l member, mill: :: specified minimum yie ld stress of the structural steel core, MPa. :: c ros s~scc ti on(l l area of the structu ral corc, JllJ1\2 :: nominal compressi ye strength of the composi tc column calcul.tted 'in accordance wit b the Specifi cation, N. :: specified compressive strength of concrete, Ml-'a. :::; specified minimum yield stress of the-ties, MPa .
:::
Equation 537- l nccd not be sa ti sfied if the nomin al strength of the reiJlforced~ c oncre te-en cas cd structural steel section alone is greater than the load effect from a load combi nati on of 1.0 D + 0.51...
b.
The max imu m spacing of tran sverse reinfo rcement along the length of the column shall be the Icsser of six' longitud inal load-carrying bar diameters or 150 mill.
c.
When specified in Secli ons 537.4.3(4). 537.4.3 (5) or 537.4 .3 (6), the maxim um spacing of transverse reinforce ment shall be th e lesser of onc~follrth {he least member dimension or 100 mm. For thi s reinforccment, cross li es, kgs of overl apping hoops, ,1IId ot her confining reinforcement shall be spaced not more th an 350 mill on centcr in the tran sverse direction.
4.
Encased composite columns in braced frames with nominal compressive loads (hat arc larger than 0.2 times Pn shall have transverse reinforcement as specified in Secl ion 537.4.3 (3)(iii) over lhe 10lal elcment length. This requirement need not be satisfied if the nomi nal strength of the reinforced-concreteencased steel section alonc is grea ter than the load effecl from a load combination of J .OD + O.SL.
5.
Composi te columns suppor1ing reactions from discontinued stiff members, slIch as walls or braced frames, 51Ia)) Ilave tr.ansverse reinforcement as specified in Sectio n 537.4.3 (3)O;i) over the. full length beneath the level at which tb e discontin uit y occurs if th e nomin al compressi ve load exceeds 0,1 times Pn . Transvcrse rein forcement shall extend into th e di scontinued member for at leas t the lengt h required to develop fuJI yielding in th e reinforced-concrcte-encased shape and longitudinal reinforcement This requirement necd not be satisfied if the nominal strength of th e rejnforced-concrete encased stlUctural steel section
537.4.3 Special Seismic System Requirements Encased composite columns in special seismi c sys tems shalJ meet the foll owing requirements in addition to those of Seclions 537.4 .land 537.4.2: I.
~~
whcre
s
1.
, -,](r' .. .J (1- -F).A I" I yh
537.4.2 Intermediate Seismic System Requirements EncHscd composite columns jn intermediate seismic systems shall mcet the following requirements in additi on to those of Secti on 537.4 .1:
= O'(l9h,.,.s
Association of Stru ctu ral Engineers of th e Phili ppines
CHAPTE I~
alone is greater th an the load effect from a load combinat ion of I.OD + O.St. 6.
Em:,lsed composite colullllls used in a C-SMF shall meet the following requirements:
a.
Transverse reinforcement shall meet the requ irements in Seetinn 537.4.3 (3)(c) at the top and bottom of the column over the region specified in Section 537.4.2.
b.
The strong-column/wctl k-bcull1 design requirements ill Section 540.5shal (bc stltisfied. Colulllll bases shall be detailed to sustain inelastic fle xur<-l l hin ging.
c.
The rcquired shear strengt h of the column shall meet the requirements of ACI 318 Section 2 1.4.5.1.
7.
When the column terminates on tl footi ng or mat foundation, the transverse reinforcement tiS specified in this section shall extend into the footin g or mat at least 300 Illm. When (he column terminates on (t wall, the transversc rei uforccmenl shall extend into the wa ll for a t least the length required to develop full yielding in the rei nforced-concrete-encased shape and longitudinal reinforcement.
8.
Welded wire f'lbri c is not permitted as transverse reinforcement for special seismic system s.
C.
The nominal shear strength of the composite column shall be the nomin al shear strength of th e structural steel section alone, based on its effective shear
2.
In addition to the requirements of Section 537.5(lj, in the special seismic sys tems described in Sections 540, 543 and 545, the design loads and column splices for filled composite columns shall also meet the requ iremen ts of Part 2a Section 521.
3.
Filled composite columns used in C-SMF shall meet the following requirements in additi on to those of Section s 6.5(1 ) and 6.5(2):
a.
The minimum requ ired shear strcngth of th e column shall meet the requirements in ACI 318 Section 21.4. 5.1.
h.
The strong~co lul1ln/wea k-beam design requirements in Secti on 521.5 shall be mel. Column bases shall be designed to sustain inelast ic flex ural hin ging.
S!Cel and
The minimuill wall th ic kness rectangu lar HSS shall be Im in =:
.fi;)./2E
k~(!lll l
:)·20/
of concrclc-/i lled (E'I. 5)7 .- 2)
for th e flat width b of each face, where b is as defined in
:!:i:'~i~:X~:i:~': .,IT;rabb:llli~C'502.4.1.
53i.S Filled Composite Columns This Section is applica ble 10 columns th at mee t the limita ti ons of Specification Section 509.2.2. Such columns shall be designed to meet the requirements of Specification Section 509, except as modified in thi s Section . I.
:)
National Structural Code of the Ph il ippi nes 6'" Edition Volume 1
~i-2()(3
CHAP1T li
~)
. St()el and Met"!:;
The nOlllin;il be,lring and shear-friction strengths shall
SECTION 538 . . ... .. .. . COMPOSITE CONNEC,l'IONS
Iw'eJ I he. reql!i r t'! . mcnl~ of ACr 1! H Chaptcr~ 10 and
I I. Unl ess a hi ghe r slrcngth is substantiated hy cyclic tcsling. the nominal hearing and shea r-fricti on strengths shall he rcdtu,;ed by 25 ·percellt for the compOsite seismic systems described in Secti ons 540, 543, 545. 547. and 548.
538.1 Scope
This Secti on is applicable to cOJlncI:tiolls in buildings thai utilize composite or dual steel and concrete systems wherein seismic load is transferred between structural steel and reinforced concre\C components.
2.
Th(> available strength or struclllral steel components in CO!!~t)osite connections shall be determined in accordance with Part 2A Hnd th e Specificati on. Structura l steel clements Ihat arc encased in confined reinforced concrete arc permitted (0 be considered to be braced agllinst () lIt ~o f~plane bucklin g. race bearing plates co nsi sting of stiffeners between the Oanges of steel beams are required when beams arc embedded in reinforced co ncrete columns or wall s.
3.
The nomin al shear strength or reinforced-concreteencased steel panel·zoncs in heam-to~column connections shall be calculated as the su m of the nominal strengths of the struclUral steel and confined rein forced concrete shear clement s as determined in Part 2A Section 540.3 and ACI 3 18 Section 21.5, respectively.
4.
Reinforcem ent shall be provided to resist all tensile forces in reinforced concrete components of the connectiolls. Additionally, the concrete shall be confined with tran sverse reinforcement. All reinforcement shall be fully de ve loped in tension or compression, as appropriate, beyond th e point at which it is no longer required to resi st the forces. Development lengths shall be determined in accordance with ACI 3 18 Chapter 12. Additi onally. development lengths for th e sys tems described in Sections 540, 543, 545. 547, and 548 shall meet the requirements of ACI 318 Section2l.5.4.
5.
Connections shall requirements:
a.
When the slab transfers horizontal diaphragm forces, the slab reinforcement shall be designed and anchored to carry the in ~ plane tensile forces at all critical sections in the slab, including cOJ,1nections to collector beams, colum ns, braces, and w'llls.
b.
For con necti ons between st mclural steel or composite beams and reinrorced concrete or encased composite columns, tran sverse hoop reinforcement ~ha ll be provided in th e connection region of the column to meet the requiremen ts of ACl318 Section 2 1.5, except for the followiilg modifications:
Composite connect ions shall be delliunstnlled to have strength, ductilit y :md tough ness co mparable to lhat exhibited by simi la r structural steel or re inforced concrete conncctions that meet the requirement s or Part 2A and ACI 318, respecti vely. Methods for calculating the connection strength shall mee t the requircment s in this Section. 538.2 General RC{luirclllcnts
COJl!leClions slwll h,l ve adequ ate def(mnalion capac it y to resist the required stren gth ilt the design slOry dri ft. Add iti onally. co nnec ti ons that arc n~ qlljrcd for the lateral stabi lity of' th e building under seismic loads shall meet Ih e requirem ents in Sections 539 through 548 based upon th e specific system in which the connecti on is used, When th e available strength of the connected members is based upon nominal material streng ths and norninal dimensions, the determination or the available strengt h or the con nec ti on shall Clccount for any effects that res ult from the increase ill th e actual nominal strengt h of the co nnected member. 538,3 Nomina l Strength of Connections The nominal strength of connections jn com posite structural
systems shall be determined on the basis of rational lllodels that satisfy bo th equi libriulll of int ernal rorces and tlw strengt h li mitation of component Ill(l{cria ls and clements based upon poten tia) limit states. Unless the cOllllec ti on stren gth is determined by anal ysis and testing, the models used for analysis of connecti ons shall meet the requirements of Sections 538.3(1) through 538 .3(5). 1.
When required, force shall be transferred betwee n structural steel and reinforced co ncrelc through (a) direct bearing of head ed shear studs or suitable l.l hern ative devices; (b)by oth er mcclwnic'll mc.U1S; (c) by shea r fri ction wi th th e necessa ry clamping forcc provided by reinforce ment normal to the plane of shen r transfer ; or (d) by a combination of thest means. Any potenti.d bond strength betwee n structural slee! and reinforced co ncrele shaH be ignored for the purpose of the connection force transfer mechanism. The contribution or different mech ani sms can be combined onl y if the stiffness and deformation capacity of the mechan isms are com patible.
meet the following additional
b. ) Stl1lctural steel sections framing into the connections are co nsidered to provide conrinemcnt over a wid lh equal to thal of facc bearing plales welded to Ihe beams between th e flanges.
Association of Structural Enginee rs of the P!lilippin es
b.2 Lap splices are pcrmitted for pcrimctcr tics when confinement of the splicc i:-; provided by face bearing plates or other me,lIlS thm prcvents sp
'~.
:'
b.3 The longitudinal bar sizes and layout in reinforced
concrete and composite columns shall be detailed to minimi ze slippage of the bars through the b~am to-column connec tion due 10 high force ~rallsfcr associated with lhe change in colll/nn 1ll01l)Cnts over the height of the connection.
539.1 Scope This section is applicable to framcs that consist of strllc!llral stc!'1 '('plumns and composite beams that are connected with ol.lrlially restrained (PR) momenl con nections Iha\ meet Ihe requirement s in Specification Section 502.3.6b(b). Compos ite partially restrained moment frames (C·PRMF) shall be designcd so that unde r earthquakc loading yielding
occurs ill the ductile compollcllts or thc compo:-;itc PI{ bcanHowcolumn mom ent cOJlllections, Limited yielding is permitled at other locmiolls. such as column base connections, Connection ncxibility and composite be am action shall be accounted for in dctermining the dynami c characlCrislics, strength and dfifl of Cw PRMF. 539.2 Columns
Structural steel columns : .: hall mect the requirements of Section 5 J 9 and 521 and the specification.
539.3 Composite Beams Composite beams shall be unenc ased , full y composite
composite scction,
539.4 Moment Connections The required strength of the bcanHowcolumn PH. moment connecti ons shall be determincd considering the effec ts of conncction nexibilil y and second-order mome nts. In add ition, composite connections shall have a nominal strength that is a( least equ al to 50 percent of M" , wh ere M" is the nominal plastic flexural strength of the connec ted structural steel beam ignoring composite action. Connections shall meet th e requirements of Section 520 and shall have a total interstorcy drift angle of 0,04 radians that is substantiated by cyclic testing as described in Secti on 522.2b. , ,','
th
National Siruclul'e:l l Code of U'18 Philippin es 6 Edition Volume 1
~;
2 10
CHAP TEH 5 - Steel and Metals
540.1 S"opc This section is applicable to moment frallles lhat consist of ei ther ciJmpositc or reinforced concrete columns und either stru cturai steel or composite beams. Composite special momcnt frames (C-SMF) shall be designed assuming that significant inelastic deformations will · occur under the dcsign earthquake, primarily in the beams. bUI with limited inelastic deformations in the column andio r con necti ons 540.2 Columns
Composite colullllls shall meet the requirements for special seismic sys tems of Sections 537.4 or 537.5, as appropria te. Reinforced concrete columns shall meet the requirem ents of ACI 318 Chapter 21. excluding Section 21.10. 540.31lcams
Composite beams that are part of C-SMF shall also meet the following requirements: I.
The distance from the maximum concrete compression fiber to the plastic neutral axis shaH not exceed
540.4 Moment Connections The required st rength of beam-to-colu mn mOlllcm connections shall be determined from Ihe shellr and flexure associated with the expected fl ex ural strength, RyMn (LRFD) or R,At" 11.5 (ASD). as appropriate. of the beams framing into the connection. The nominal strength of lhe connection shall Illeet the requirements in Section 538. In addition, the connections shall be capable of sustaining a total interstory drift angle of 0.04 radian. When be ~1'.!1 flanges are interrupted at the connec ti on, the connections shall demonstrate an interstory drift angle of at least 0.04 radian in cyclic tests that is sub~talltiated by cyclic testing as described in Part 2ASecti on 540.2.(b). For co nnections to reinforced concrete columns with a beam th at is continuous through Ihe column so that welded joints are not required in lhe flanges and the connection is not otherwise susceptible to premature fraclurcs, the inelastic rotat ion capacity shall be demonstrated by tcsling or oth cr substantiating data. 540.5 Column-Beam Moment Ratio The design of reinforced concrete columns shall meet the requirements of ACI 318 Section 2 1.4.2. The column-tobeam moment ratio of composite columns shall meet the requirements of Part 2A Section 522.6 with the following modifications: 1.
The available Oexural strength of the composite column shall meet the requirements of Specification Section 509 with consideration of th e required axia l slrength. Pre·
2.
The force limit for Exception (a) i n Part 2A Section 522.6 shall be P" < 0. 1P, .
3.
Composite columns exempted by the minimum flexural strength requirement in Part 2A Section 522.6(a) shall have transverse reinforcement that meets the requirements in Section 537.4.3(3).
(Eq.540 -1)
1700Fy
1+ - - -
(
)
E
where
= di stance from the lOp of the steel beam to the lOp of concrete, mm. = depth of the steel beam, mm. = specified minimum yield stress of the steel beam, MPa
E 2.
= elastic modulus of the steel beam, MP" Beam flanges shall meet the requirem ents of Part 2A Section 540.4, except when reinforced - concre te ~ encased compression elements have a reinforced concrete cover of at least 50 mm and confinement is provided by hoop reinforcement in region s where plastic hinges are expected to occur under seismic defonnations . Hoop reinforcement shall meet th e requirements of ACJ 3 18 Section 21.33. Neither structural steel nor composite tnlsses are permitted as Oex ural members to resist seismic loads in C~SMF unless it is demonstrated by; testin g and analysis that the particular system provides adequate ductility and energy dissipation capacity.
Association of Structural Engineers of the Philippin es
CHAPlET!
~;
Steel ailel Mc!al
~)-211
541.1 Scope
542.1 Scope
This Section is applicable to moment frames tl1al consist of cithcLcompositc or reinforced concrete columlls and either
This Section is applicable to mOlllenl frames that consist of either composite or reinforced concrete columns and structural steel or composite beams. Composite {)r
structural sleel or (:ompositc beams. Composite intermediate
monient frames (C-IMF) shall be designed assuming that inelastic deformation under the design earthquake will occur primarily in the beams, but with moderate inelastic deformation in the columns and/or connections.
542.2 Colullllls. 541.2 Columns
Composite columns shall
meet
the requirements
for
intermediate seismic systems of Section 537.401' 537.5.
Reinforced concrete columns shall meet the requirements ACI 318 Section2!.12.
or
541.3 Beams Structural stee! and composite beams shall
meet the
Composite columns shall meet the requirements for ordinary seismic systems in Section 537.4 or 537.5, as. appropriate. Reinforced concrete columns shall meet the requiremcnts of ACI 318, excluding Chapter 21. 542.3 Belllns Structural steel and composite beams shall meet the requiremcnts of!hc Specification.
requirements of the Specification. 542.4 Moment Connections
541.4 Moment Connections Tile nominal strength of the coonections shall meet the requirements of Section 538. The required strength of beam-lo-column connections shall meet one of the following requirements: 1.
The required strength of the connection shall be based on the forces associated with plastic hinging of !he beams adjacent to the connection.
2.
Connections shall meet the requirements of Section 538 and shall demonstrate a total inters tory drift angle of at least 0,03 radian in cyclic tests,
Connections shall be designed for the load combinations in accordance with Specification Sections 502.3.3and 502.3.4, and the available strength of the connections shall meet the requirements in Section 520 and Section 524.2 of Part 2A.
th
National Structural Code of tile Philippines 6 Edition Volume 1
~S-212
CH AP'/[: F{ :> Steel and Mu tals
544.1 Scope 543.1 Scope This Section is applicable to braced framcs that consist of concentrically co nnc cted members. Minor eccentricities :.I rc permilled jf they Hre accounted for in the design. Colunins shall be struct ural steel , composite stru ctural steel , or reinforced concrete. Beams and braces shall be either structural steel or composite stl1l clllral steel. Composite special concentrically braced frames ( C ~CBF) shall be designed assuming that inelastic acti on under the design earthquake will occur primarily throu gh tension yielding and/or buckling of braces.
543.2 Columns Sti'UC!uml steel columns shall lIlee t the requ iremellts of Pm1 2A Sections 537 and 539. Composit e columns shall meet the requirem ent s for special sei smic systems of Section 537.4 or 537.5 . Reinforced concrete columns shall meet the requirements for structural truss clements of ACI 3 I 8 Chapter 21. 543.3 Deams Structural steel beams shall meet the requirements for special conce ntri cally braced frames (SC BF) of Part 2A Section 526. Co mposite beams shall meet the requirements of the Specificflli on Sectioll 509 and the requirements for special concentrically braced frames (SCBF) of Part 2A Section 526. 543.4 Ilraces StruclUral steel braces shall meet the require ments for SCDF of Prul 2A Sec ti on 526. Composite. braces shall meet tile requirements for co mposite columns of Section 543.2.
This Section is appli cable 10 concentrically braced frame systems that consist of composite or reinforced concrete columns. structural steel or composite beams. and structural steel or composite braces. Composite onJinary braced frames (C~OBF) shall be designed assuming that limited inelastic action under lhe desig n cal1hquake will OCc ur in th e beams, column:;, braces, and/or connecti ons. 544.2 Columns Encased composite columns shall meet the requirements for ordinary seismic systems of Sections 537.4. Filled composite columns shall meet the rcquircmcnts of Section 537.5 for ordinary seismic systems. Reinforced concrete columns shall Illeet the requiremen ts of ACI 3 18 excl udin g Chapt er 21. 544.3 Beams Structural steel and co mposite beams shall meet the requirements of the Speci fi cation. 544.4 Draces Stru ctural steel braces shall meet the requircme nts of thc Specifi cation. Composi te braces shall meet th e requirements for composite co/umlls of Sections 537 .4<1, 537 .5, and 544.2.
544.5 Connections Connections shall be designed for the Joad combinations in accordance with Specification Sections 502.3.3 and 502.3.4 , and the available strength of the connections shall meet the requirements in Sec ti o J ~ 538.
. ' :, .).,. " ., '~"
543.5. Connections Bracing connec ti ons shall meet the requi rements of Section 538 and Part 2A Section 526.
Associalion of Siruclural Engineers of the Pllilippincs
'. '; ,
>',
C HJ\Pl"I:n~)
SECTION 545
qpMtfO~IrE ll;P;~N1;~~A!~,"Y .
BRACED FRAMES (C·EBF)
545.1 Scope This Sect ion is applicable to braced frames for which one end o f each brace intersects a beam al an eccentricity from th e intersection of the cC!Hcrlincs of the beam ,IIHI co lumn , or intersects a beam at all ecce ntricit y from the in tcrsCC: li oll
~; lee l
and rv1e tal
S-2 13
545.4 Ilraecs Structural steel braces 'shall meet the requirements for EBF of Part 2/\ Section 528 . 545.5 Conllcdions
In addition to the requ iremen ts fo r ESF of Part 2A Section .128, connectio ns shall meel the requirements of Section 520.
of the centerlines of the beam and
Composite eccen trically braced frames (C>EBF) shall be designed so that inelastic deformation s under the design carl hquak c will OCClIr only as shear yielding in l ile links.
Diagonal braces, columns, and beam scgm en Is olltside of th e link shaH be designed to remain essentially clastic under the maximum forces that can be- gCllcfmcd by the fully yielded and strain-hard ened link. Columns shall be either compos ite or reinforced concrete. Braces shall be struct ural steel. Links shall be stnlctural steel as described jn this Sectioll. The avai lable strength of members sha ll meet the requiremellts ill (he Specification, except 'IS modifi ed in th is Section. C-EBF shall meet the requiremen ts of Pari 2/\ Section 528, except as modifi ed in this Section. 545.2 Columns Reinforced concrete columns shall meet the requirements for structural tru ss clements of ACI 3 18 Chapter 2 J. Composite columns shall meet the require-ments for special seismic systems of Secti ons 517.4 or 537.5. Additionally, where a link is adjacent to a reinforced co ncrete column or encased composite column, tran sverse col umn reinforcement meeting the requirements of ACI 318 Section 2 1.4 .4 (or Sect ion 537.4c(6)a for composite co lumn s) shall be provided above and below the link connection. All
columns shall meet the requirements of Part 2A Sect ion 528.10. 545.3 Links Links shall be uncllcased stlllctural steel and shaH meet the
requirement for eccentrically braced frame (ESF) link s in Part 2A Section 528 . It is pel"mi Hed ( 0 encase the portion or the beam outside of the link in reinforced concrete. Beallls cont aining the link arc permitted to act compositely with the floor Sl;lb lIsing sI\c
111
N(llional Structural Code of lhe Philippines 6 Ed ition Volume 1
[5- ?1 t1
CHAprF F~
5 . Steel and Metals
546.3 Steel Coupling /leallls StruclUral steel coupling beams lhm am used be twee n ( V.'O adjacent reinfo rced concretc wall s shall meet th l: requircments of the Speci fica ti on 1l11d th is Secti on: !.
Co upling bea ms shall have tin cmbcd mcllI Ic ngth into Ihe rei nforced concrete wa ll tl1m is suffi ci ent 10 de vel o p the maximum possiblc combi nati on of momcnt and shear that ca n be gcncnlled by the;,!lominal bending an d shear strength of the coupling bea m. The embcdnH:: :i length shall be considered to begin inside th e first lay, ·; of confining reinforcement in the wall hou nda !-~; member. Connecti on strength for the transfer of h id ·: between the coupling beam an d the wall shall meet tlh~ requ irements of Section 538.
2.
Vertical wa ll reinforcement with nominal axiHJ streng th eq ual 10 the nominal shear stren gth of th e coupling beam shall be placed over the embedment length of the bea m with I wo ~lh i rd s of the steel located over the firs t half of lhe embedment length. Thi s wall reinforceme nt shall extend a dist ance of at l ea~! one tensio n de ve lopment length above ,lI1d below the fl anges of' the co uplin g beam. It is permitted \ 0 usc vertic;,\ reinforcement placed for oth er purposes, such as fe,,' verti cal bo und ary members, as par1 of Ihe requ ired verti cal rei nforcement.
546.1 Scope
The requirements ill thi s Sec tion apply when rei nforced concrete wa lls are composilc wit h slmcturaJ stcel elemcnts, either as infill panel s. such as reinforced co ncrete walls ill stru ctural steel frames with unencased or reinforced ~ concrcte ....encased structllrlt l steel secti ons Ihal act as boundary members, or as stl1lctural steel coupling beams that connect tw o adjacent reinforced concrete wall s. Reinforced concrele walls shall meet the requ iremenls of ACI 3 18 exciliding Ch apter 21 .
546.2 Boundary Member·s
Boundary mcmbers shall /Hect th e requ irement s of this Secti on: I.
2.
When une ncased structural steel sections fun ction as boundary mem bers in reinforced concrete infill pa nels, the structural steel sec ti ons shl1li meet the requi rements of the Specificati on. The required axial strength of the boundary mem ber shall be determined assuming lhal the shear forces are carri ed by th e rei nfo rced concrete wall and the entire gravit y and ove rturnin g fo rces are carri ed by [he boundary mem bers in conjunction with the shear wal l. The rei nforced concret e wall shal l meet the requirements of ACI 31 8 excl uding Chapter 21. When reinforc ed ~con crete ~ encas ed shapes fun ction as boundary members in reinforced concrete infill panels, the anal ys is shall be based upon a transfonn ed concrete section using clastic material properties. The wall shall meet (he requirements of ACI 3 J 8 excluding Chapter 21. When the reinforced~ c on c ret e ~en c ased structural steel boundary member qu alifies as a composite colum n as defined in Speci fication Secti on509, it shall be designed to meet th e ordinary seismic system requirements of Section 537 .4a. Otherwise, it shall be designed as a composite column lO meet the rcquirements of ACJ 318 Section 10.16 and Section
546.4 Encased Composite Coupling Beams Encased co mposi te seclions servin g as co upling beams sh all meet the requirements of Section 546.3 as modified in [hi:'. Section: I.
Coupling beams shall have an e m bedme nt Icnglh into the rcinforced concrete wall tl1at is suffi cient to deveJ o)' the maximum possible comb ination of momen t
2.
The nominal shear cap acity of the encased composi te steel coupling beam shall be used to meet the requirement in Section 546.3(1 ).
3.
The stiffness of th e encased composite steel coupli ng beams shall be used for calculating th e req ui red strength of the shear wall and coupling beam.
4.
509 of the Specifi cation.
3.
l"Icad eci shear stu ds or welded rein forcement anchors shall be provided to transfer vertical shear fo rces between thc structural steel an d reinforced concrete. Headed she ar st ud s, if used, shall meet th c req uircmctH s of Specifica tion Section509. We lded rei nforcement anchors, if used, shall mee t thc requirements of AWS D1.4 .
Association of Structural Engineers of the Philippines
requirements for boundary members of AC I 3 18 Section 21 .7 .6.
547.4 Encased Composite Coupling Beams Encased composite sec ti ons serving as coupling beams shall Illeet th e requirements or Section 546.3, except the req uirements of Pm1 2A Section 528.3 need not be met. 547.1 Scope Special reinforced concrete she'::1 walls composite with structural steel elements (C·SRC W) syste ms shall meet Ihe requirements of Section 15 for C-ORCW and the shear-wall requirement of ACI 318 including 0haptcr 21 , except as modifi ed in this Section.
547.2 Boundary Members In addition to the requirements of Section 547 .2( I) , uncncascd structural steel columns shall meet the rcqu ircrncnts of Pa rt 2A Sect ions 519 and 521. In addition to th e requirements of Section 15.2(2). rhe requ ire ments in this Section s hall apply to walls wi th
rei nforced-conc ret e-encased structural steel boundary members. The wall sh all meet the requirements of ACI 3 18 incl udin g Chapter 2 J. Rcinforccd -co ncrctc-cncascd st ructural steel boundary me mbers that qualify as co mp()site columns in Specification Section 509 shall meet the special seismic sys tem requi re ments of Section 537 .4. Otherwise, such mc mbers shall be designed as co mpos ite compression members to ' meet the requi rc mclHs of AC I 318 Section 10.1 6 includ ing the special seismic req uirements for boundary members in ACI 318 Section 2 1.7.6. Transverse re.inforcemcnt for confin ement o f th e composit (: boundary member shall ex tend a di stance of 2h into the wall , where h is the overall depth of th e boundary member in the plane of the wall. Headed shear studs or welded reinforcin g bar anchors shall be provided as specified in Section 546.2(3). For connection to uncncased structural steel sections, the nominal stren gth of welded reinforcing bar anchors shall be reduced by 25 percent from their static yield strength.
547.3 Steel Coupling Beams In addition to the req uirements of Sec tion 546.3, structural steel coupling beams shall meet the req uirements of Part 2A Scctions 528.2 and 528.3 . When requ ired in Part 2A Sec tion 528.3, the cou pling rotation shall be assu med as O.OS radian unl ess a smaller valu c is justified by rational anal ys is of the inelastic deformati ons thlll are ex pected under the des ign ea rt hquake. Face bea ring plates shall be provided 011 both s ides of th e coupling beams at the face of the reinforced concrete wall. These stiffeners shall meet th e detailing requi rements of Part 2A Section 528.3. Ve rtical wall reinforcement as specified in Secti on 528.3(2) shall be confin ed by trans verse reinforcement that meets the
1h
National Structural Code of the Philippines 6 Edition Volu me 1
~) ·· 216
CHAP T£: H 5 - Steel and Melal:.
members wit h we lds andlor slip-crit ical high- strength bolts to develop Ihe nom in al shea r strength of the plate. The design of welded and bolted con nectors shall meet the additional requirements of Part 2AScction 520.
Section 548.1 Scope
548.3 Boundary Members
This Section is applicable to structural walls consisti ng of stee l plnt cs with reinforced concrete t!1casemcnl 0 11 One or bOlh sides of the plate and structulaJ steel or compos ite boundary mcmbers.
Structural steel and composite boundary members shall be designed to resist the shear capacity of plate and any reinforced concrete p0I1iol1s of the wall active at the design story drift. Composite and reinforced co ncrete boundary members shall also meet th e requi rements of Section 547.2. Steel boundary members shall also meet the requirements of Part 2A, Scclion 530.
548.2 Wall Elements The avail able shca r slrcnglil sha ll be 9'Vns (LRPD) or V,jj I n (AS D), as appropriate, according (0 the limit slate of shear yielding o f composite steel plate shear wa lls (C·SPW) wit h
" stiffened platc confomling 10 Seclion 530.2( 1) shall be (Eq.548-1 )
= 0.90 (LRFD)
n = 1.67 (ASD)
V".,
::;: nomi nal shear strength of the stee l plate, N
A sp
= horizontal area of stiffened steel plate, mrn 2.
f~\.
= speci fied minimum yield stress of the phnc, MPa.
548.4 Openings Boundary members shall be provided around openings as re~cd b ~ ana lysis.
..:'~~!~.3~_r~)~~~::~~1~Z~~~!~'~~.~I!~:~~~~~~)\\1~~!~t·:W~~t\~~~1¥~~:
The ava il ab le shear strength of CwSPW with a plate that does not meet the stiffening requirement s in Section
530.2(1) shall be based upon Ihe strenglh of the plate. excluding the strength of the reinforced concrete, and meet th e req uiremen ts of the Specification Secti ons 507.2 and
507.3. I.
The stecl plale shall be adequ alely sti ffened by encasement or aU8chmcnt to the reinforced concrete if it can be demonstrated with an elastic pi me buckling analysis that the composite wall can resist a nominal shear force equal to V,lS . The concrete thickn ess shall be a minimum of 100 111m on each side when concrete
is provided on bOlh sides of the Sleel plale and 200 mm when concrete is provided on one side of the stcel plate. Headed shear stud connectors or other mechanical co nn ectors shall be provided to prevent local buckl in g and separation of the plate and reinforced concrete . Horizonta l and vertical reinforcement shall be provided in the co ncrete encasement to meet or exceed the detai li ng requirement s in ACI 318 Secti on 14.3. The rei nforcement rat io in bot h directio ns shall lIot be I c~:-; (han 0.UU25 ; (he ma ximum spaci ng between bars shall not exceed 450 111111.
Seismic forces acting perpendi cu lar to the plane of the wa ll as specified by this code shall be considered in the design of th e compos it e wall system. 2.
The steel plate shall be continuously connected on all .edges to structural steel framing and boundary
Associ ation of Structu ral Engineers of the Philippin es
CHAPTEn. [;
Steel and Mel,1l
0·21 7
When required by Ih is code or thc cngineer-or-record, a qu alil y assu rance plan .s hall be pro vided. For th e sleci portion or the cOllstructi on, the provisions of Part 2A, Secti on 53 1 apply. Structural design drawings and specifications, shop drawings, and erection drawings for composite steel mId steel building constructi on shall meet the requircmcn ts of Pal' 2A $eclion518. For reinforced concrete and composite steel building construction, the con tract documents, shop drawings, and crec tion drawings shall also indicate the followin g:
I.
Bar placement, cutoff<;, lap and mechani cal splices, hooks and mechanical anchorages.
2. Tolerance for phlccment of tics and other transverse rei nforccll1cllI .
3. Provisions for dime nsional changes resulting from tem perature changes, creep and shrinkage. 4.
Location, magni tude, and sequenci ng prestresssing or posH ensio ning present.
5.
If concrete floor slabs or slabs on grade servc as diaphragm s, connecti on details bet ween the diaphragm and the mai n l a {eral~ l oad resistin g system shall be clearly identified .
of
any
National Structura l Code of the I'llilippines 6'" Edition Volu me 1
~) · ?18
CHAPTUi
~) .
Sleel and Metals
bf ' b ,.b, h,.h] C , I,' .,
,'d!
.' "
A
full unreduced cross-sectional arC,l of member
A
Area of dircctly connected elements or gross area hfl + A for bearing stiffcner at interior SUppOJ1 and or under concentrated load , and b21 + As, for bearing stiffeners at end support Gross cross-sectional area of bolt 18t2 .... A Sh for beari ng stiffener at interior support ()f under co ncentrated load, and IOl2 of- A s!. for bearing stiffeners at end suppor! Effec tive area al stress Fu
AI;
Ab Ac
Ae
N Ag Ag
j ,
Effective net area Cross-sec tional area of compression flan ge plus edge stiffener Gross area of element including stiffeners Gross area of section
a
Gross arca subject to shear Net area subject to tension Nct area subject to shear Net area of cross-section Reduced area due 10 local buckling Gross-sectional area of roof panel per unit width Cross-sectional area of hearing stiffene r Gross area of stiffener Gross area of shear stiffener Net tensile area Area of web Net web area Shear panel length of unrein forced web clement, or distance between shear stiffeners of reinforced web clements Interncdiatc fastener or spot weld spacing F
1J,.
Term for determinin g tensile yield point of corncrs
b b
Effect i ve design width or compression element
Agv A n! A ll v All
Ad AI' As As A s!
Ar Aw Awn
a a a
",f b,
b, b, or
b, ba
Flange width Effective wid th for oeOection calculati on Effec ti ve width of elements, located at ce ntroid of clement including stiffeners Effecti ve width Effect ive width determined eithcr by section 552.4 Section 552.5. 1 depending on Sliffness of stiffeners Total flat width of stiffened element Tolal Oat width of edge stiffened elemen t
C
C
eh Cr C"
Cm Cmll: Cmy
CN C" CR C,
C rF
C Cw C wr
Cy C"C"
La rgest sub-elemen t nm width Effective widths Effective widths of bearing slifTcncrs For comprcssion mcmbers, ratio or total corner cross-sectional area to tOl1l1 cross-sec tional area of full section; for nex uJ"ClI members, ratio of tOlal corner cross-sect ional area of co ntrolling llangc to full cross-sccti cmal area of COJl trolling flange Coefficicnt Bearing factor Bending coefficient dependent on moment gradient Constant from T able 557. 1 Web slenderness coefficient End moment coeffi cient in interacti on formula End moment coefficient in interacti on formula End moment coefficient in interacti on formula Bcaring length coeffi ciellt Correction factor Inside bend radius coefficient Coefficient for lateral-torsional buckling End moment coefficient in interactioll formula Shear stiffener coefficient Torsional warping co nstan t of cross-sec tion Torsional warpin g constant of fl ange Compression strain factor Axial buckling coefficients
C3 ClIO
Coefficients tabulated in Tables 554-3 to 554-5
C6
CI/>
Calibration coefficient
c c
D D
Strip of flat wi dth adj acent to hole Distance . Amount of curling displacement Horizontal distance from edge of clement {o centerline of stiffener Outside diameter of cyl indrical tube Overall depth of lip
D D DZ, D3
Shear stiffener coefficien t Dead load Lip dimension
d
Depth of section
d
Nomi na l screw diameter
d d d
Flat depth of lip defined in Figure 552·') \Vid th of arc sca m weld Visible diameter of out er surface of arc spot weld
'f ci
Diameler of boll Average di amcter of arc spol weld at mid thickness of t Average width of seam weld
Association of Structural Engineers of the Philippines
CHAPTEJi S
db fI,. d,. d"
(h "" dj1iJ d~
ds d ·,
d".,\ d" E
Nominal diamcter (body or shank diamclCr) Effcctive diamet er of fused area Effective width of arc scam weld at fused surfaces Diameter of hole Depth of hole Dia meter of sl.mdard hol e Distance alon g roof slope between the itll purljJl line and thejth anchorage device Reduced effective width of stiffener Depth of stiffener Effective width of stiffener calculated according to Section 552.3 Screw head or washer diameter Larger value of screw head or washer diameter
E'
e
Tensile strength of virgin steel specified by Section 55 J.2 or establi shed in accord ance with Section 556.3.3 Lower value of Fy for beam web or Fy.\ for bearing stiffe!lerS
Tensile strength of electrode classification FI/I
Mod ulus of elasticity of steel , 203,000 Mpa, or 2,070,000 kg/cm'
F"
e
e nl ;"
C~x,Csy
'.,. F F.SJI
Pm Fl·
Fer Fd
Fc Fe I;~>I F~,
Fn Fill l'~II. F'nl
Fsy
Li ve load due to earthquake Twist of stud from initial, ideal, unbuckled shape Reduced modulus of elasticity for flexural and ax ial stiffness in second -order analysis
Distance measured in line of fOJ'ce from center of a standard hole to nearest edge of an adjacent hole OJ' to end of connected part toward which the force is directed Distance measured in line of force from center of
5·2 Hl
5.11.2.2, 551.2.3 Nominal tensile stress in flat sheet Tensile strength as specified in Section 551.1.1. 551 .2.2, or 551.2.3.
F'.\. E
Steol ,Hld Melal
Tensile strength of members in co ntact with screw head Tensile strength of member not in contact wilh screw head Nominal shear stress Yield stress used for desi gn, not to exceed specified yield stress or stabli shcd in accordan ce with Section 556, or as increased for cold work of fonnalling in Section 551 .7.2 or
nat
pOl1ions
Yield stress of stiffener steel Tensile yield stress of virgin steel specified by Section 551.2 or established in accordance with Section 556.3.3
f
Stress ill compression element co mpweci 011 has is of effective design width Average comput ed stress in full unreduced fl ange width Stre ss at service load in cover plate or sheet Normal stre ss du e to bending alon e at the maximum nonnal on the cross section due to combined bending and torsio n Normal stress due to torsion alon e at the maximum normal stress on the cross section due to combined bending and torsioll. Co mputed compressive stress in clement being considered. Calculations are based 011 effective section at load for which serviceability is determined. C6m puted st resses fl and f2in un sti ffened clement, as defined in Figures 552-5 10 552.8. Calculations arc based on effec tive section at load for whi ch serviceability is determined. Required shear stress on a bolt Stresses on unstiffened element defi ned by Figures 552-6 to 552-8
National Structura l Code of the Philippines 6 'h Edition Volume 1
:5"2:<'0
CHAP1Tf::J
:i " 5 10el anej
Me tals
Stresses at the opposite ends oj" web G
Shear modulus of sleel. 78,000 Mpa or 795,000 kg/e m'
g
Vertical dislance betwcclllWO rows of" cOllnections nearest to top an d bouom flanges Transvcr.'i( ! (enler-Io-cenler spaci ng between faste ner gage lines Gauge. spacing of fastene r perpendicular to force
g g
II
A pennancllI load due to lateral canh prcssure, incl uding groundwater
h
Depth of fl.H portion of web measured along pl ane of web
section parallel to web using ullrcduc.:cd sect ion y-ax is moment of incrlia of llange Index of stirre ner Index of each purlin line .I
Saint-Venant torsion constant
il
Saint- Venum torsion constant of
compression flang plus edge stiffener about an x-y axis located at Ihe centroid of the nangc Section propcI1y for torsional-flcxural buckling Index for cach anchoragc device
j j
K K'
" h" Iz, h,,"("
h,
Width of clemcnts adjoining 5ti ffelled clement Lip hcight as defined in F"igurcs 555· 15 to 555 · 18 Overall depth of unstiffcncd C-scct ion member as defined in Figure 552-8 Depth of soil supPOJ1ed by the structure Coped nat web depth x di 51
Ka Kat
K,.IJ;J Knq KJ)"S
K, K,owli
Importance faclOr for earthquake K", "
Iw I"
I'JJ I, I,
Importance factor for wind Adequa te moment of inertial of stiffe ner, so that each compo nent elemcnt wil! behave as :1 st iffe ned clement Effective momcnt of inertia Gross moment of inenia Actual moment of inertia of full stiffencr about its OWJl centroidal axis parallel to element to be stiffened Minimum moment of inerti a of shear stiffen er(s) with respect to an axis in plane of web MOlllenl of inertia of .stiffener about ccnterl ine of flat pon ion of element Moment of in cliia of full unreduced
section abou t principal axis x-axis moment of inertia of the fl ange Product of inertia of full unreduced section about major and minor cen troida! axes Product of inerti a of flange about maj or and minor centroidal axes Moment of inertia of co mpression pOl1ion of secti on about centroiclal ax is of ent irc
Effective length factor A constant Lateral sti ffncss of :'lnchoragc dcvice Parameter for determini ng axial strength ofZ-Secti on member having one fl ange fastened to sheating Effective lateral stiffness ofjth an chorage device with respect to ilh purlin Required stiffness Lateral stiffness of roof system, neglect in g anchorage devices Effective le ngth factor for torsion Effective lateral stiffncss of all elements resisting force Effective length f
K.r
Effecti ve length factor for buckling about y- axi s Plate budding cocfficicnt Plate buckling coefficicnt for di slortiOTwl bll<:kJi ng
k K if
Kille"
K," K¢ k¢jl"
k" /I: k{o,,"," k." (1
"""~
Plate buckling cocfficicnt for local sub-element buckling Shear buckling coefficient Rotational sti ffness Elasti c rotati onal stiffness provided by the flange to the flange/web juncture Geometric rotat ional stiffness demanded by the Oange from the Dangc Iwcb juncture Elastic rotational stiffncss provided by thc web to the flan ge/web juncture Geometric rotational stiffness demanded by the
web from the flan ge/web juncture L
Full span for simple beams, distance h CI \'.'C{'Jl inflecti on point for continous bea ms, I\"j , ' : member length for cantilever beam s Span length
Association of Structural Engineers of the Philippines
C HAP'lT. H~)
Lcngth uf weld Lcngth of longitudi nal welds Len gth of SCll m weld not in clu ding circ ular Lengt h of con necti on l1nbraced length of member
L,
L" L,
Lv
Lt/
M M
Req uired allowable flexural slrenglh, ASD Bending moment M ud Distortional buckling moment M err Overall buckling moment A1u! Local buckling moment A1d Nominal moment with consideration of dcflection MJ Facto red moment MJx . Moments due to factored )o
Nominal flexural strengths ,thout Section 551 Nom ina l flexural strengths IrcsistanceJ about Cell troidal axes J elef"llll!lcd in accordance willi Section 553 .1 excl ud ing provisions of Secti on 553 . l. l.b Nomi nal flex ural strength abou t cen troid.d axes determined using gross , unreduced cross-secti on propenics
M~,
Requi red all owable fl exura l stren gth wit!: respect .\ '. to ccntroid al axes for ASD
My
M
Required fl ex ural strength with respect to Cenlroid"1 axes for LRFD moment causi ng maximum strain c)' Yi eld momelll (= S,F,) Small er end moment in an 1I1lhraccd scgmenl Larger and moment ill an unbraced seg men t Required flexural strength
M,
Required n exural strengt h
M" M"y M,. My M,
M,
My
M,
Torsional momen t. of required load P aboll l shear center
III
Degrees of freedom Teelll fro determinin g tensil e yield point of corners Distance frolll shear center of one C-section to mid -plane of web. Modifi cation factor for type of bearing connection
1/1
III
N N
N" N, N /I " /I /I /I /I
/I
Me M 'l
Nom inal flexural strengt h Nominal flexural strength for distortional buckling Nomina l flexura l slrenglh for overall buckling Nominal flexu ral sirengih for local bu ckling
:)-2;: 1
M,u. l!1l(is
Overa lilen gih Live load Minimum of L", and Lm Distance bet ween braces on one compressio n IllclJ} ber Unsupported length between brace points or other restraints which restrict distOl1iolwi buckling of clcment Summation of critical path lengths of each segment Critical unbraced length of distortional buckling Gross failure path length parallel to force Lenglh of hole Distance between discrete restraint s thai restrict distortional buckling Net fai lure path lengt h parallel to force Overhang length measured frolll the edge of bearing (0 the en d of me mber Net fai lure path len gth inclined to force Length of bearing stiffener Un braced length of compression l11em hcl for torsion Net failure path length normal to force d ue to direct tension Lim it of lInbraced length below which IHleral torsional buckling is not considered Unbeaced leng th of compression member for bending about x-axis Unbraced length of compression member for ucndill g about y-axis Length at which local b uck ling stress eq uals flexural buckling stress Dsitance fro m concentrated load to a brace
SIt'QI Jild Melal
p
Actual length of bearing Num be r of stress range flu ctuations in design li fe Number of anchorage devices along a lin e of anchorage Notio nal lateral load ap plied at level i Number of purlinlines on roo f slope Coefficient Number of stiffeners Number of holes Number of tests Num ber of equ ally spaced intermediate brace locati ons Number of anchors in test assemb ly with same tribu tary arc,} (for anchor fai lure), or number of pan els with identical spans and Jocad ing to failed span (for non -JTlchord -failure) Number of threads per inch Number of boll hol es Numbe r of compression flange stiffeners Number of web sti ffeners andlor folds Number of tension fl ange st iffe ners Required allowable stre ngth fo r co ncentrated load reaction in presence of bendi ng moment for AS D
National St ructural Code of the Philippines 6'" Edilion Volu me 1
5.222
CHAPTEli :; . Steel ami Melnls
p
Required allowable strength (nominal force ) transmitted by weld lor ASD Required ll llowahle compressive axia l strength for AS!) Professional factor Required concentrated Jocad within a distance of O.3a on each side of a brace. plus 1.4 (! -lIa) Ii mes each required concentrated load located fan her than O.3a but not farther than 1.0a from the brace Required nominal brace strength for a single compression member Elastic buckling strengths
p p p
p
Pu,P u Lateral bracing forces Lateral force to be resist ed by the jlh anchorage Plj device Dis(Qr1ional buckling load Petti Local buckling load P..rl Axial force due to factored loads 1', Conce ntrateu load or re~lc tio n due to facto red loads 1', Lateral force introduced into the system al the ilh I' , purlin Mean va lue of the tested-tn-predicted load ratios Nominal web crippling strength Nominal axial strength of member Nominal axial strength of bearing sti ffener component Nominal strength of connection Nominal bearing strengt h Nominal tensile strength of welded member Nominal bolt strength Nominal web crippling strength of C· or Z-Section with overhang(s) Nominal axial strength for distOl1ional buckling Nominal axial strength for overall buckling No minal axial strength for loca l buckling Nominal axial strength of member determined III accordance wit h Section 553.3.4 with F,,=F,< Nominal pull-out strength pel' screw . Nom inal pull~over strength per screw Nominal shear strength per screw P,,~ Nominal tension strength per screw 1'" Required axial compressive strength 1', Concentrated load or reacti on 1', Nominal shear strength of screw as reported by PS .1 manufacturer or determined, by independent laboratory testing Nomina! tension strength [resistance] of screw as reported by manufacturer or determined by independent laboratory testing Required axial strength for LRFD weld, for Factored force transmitted by LRFD Pu Required strength for co ncen trated load reaction in presence of bending moment for LRFD Pwe Nominal web crippling strength for C-
1).1\
I'\" j;
I)
"
Section flexlJI"lll member Components of required loml P parallel ax is. res pectively Me mbe r yield strength
\0 x and
Required strengt h for concentrated load o r reaction concentrated load reaction due 10 factored loads ill presence of bending moment Required compressive axial strength Pitch (mm per thread for SI units and cm per thread for MKS units)
Q
Req uired allow(lb le shear sl rength of connecti on
Q
Required shear strength ofconnection
Q, q
Load effect Design loead in plane of web Reduction facIO!"
CfJ
Ii
I? Ii II
R
y
Required allowable strengt h for ASD Modification fac tor Reduction faclor Reduction factor Reduction factor determined from uplift tests in accordance with AISI S908 Coefficient Inside belld radius Radius of outside bend surface lJ / la
r,
Allowable design strength Reduction factor Reduction factor effect of factored loads Nominal strength Nominal block shear rupture strength Average val ue of all test results Reduction factor Req uired strength for LRFD Correction facto r Least radius of gyration of full unreduced cross~ section Centerline bend radius Minimum radius of gyration of full unreduced cross-section
r"
Polar radius of gyration of cross-section about shear center Rad ius of gyration of cross-secti on about cenlroid al prinCipal axis
s
128 fEj!"
s
Variable load clue to snow, including ice and associated rain or rain Elastic section modulus of effective seel ie :) calculated relastive to extreme compression fiber ::~ F, Elastic section modulus of effecti ve section calculated relative to extreme compression or
s,
s,
. Association of Structural Engineers of the Philippines
CHAPTEFi S
tension fiber at F I,
S" .\' .\'
,\'
.\' S
T T T
T T
I, I, I;
I., Ill' I, , I, I, I,
U
V
V, Vf Vf VM V" Vp
VQ
Steel (Inc! Metal
~)-223
V"
Required shear strength for LRFD
Elastic scclion s~>ction modulus of full unreduced section relative (0 extreme compression fiber Elastics section modulus of full unreduced section relative to extreme fiber in firs! yield
V"
Required shear strength of connection for LRFD
V
Required shear strength
In-plane diaphragm nominal shear strength Ccntcr-Io-ccnlcr hole spacing Spacing in linc of .slress of welds, rivets, or boils connecting a compression cover plate or sheet to a nOll-integral stiffener or other clemen!
W W
Wind load, a variable load due to wind Required strength from critical load combinations for ASD, LRFD, or LSD Total required vertical load supported by irh purlin in a single bay Components of required strength W Flat width of element exclusive of radii Flat width of beam flange which contacts bearing plate Flat width of narrowest unstiffened compression element tributary 10 connections Width of Oange projection beyond web for 1-
Sheet width divided by Humber of bolt holes in cross-section being analyzed W tId spacing Pitch, spacing of fastener parallel 10 force Longitudinal ccnlcr-tQ-ccntcr spacing of any consecutive holes Clear distance from the hole a1 ends of member Maximuill permissible longitudinal spacing of welds or other connectors joining two C-sections to form an I-section
Required allowable tensile axial strength for ASD Required allowable tension strength of cOllllection Load due to contraction or expansion caused by temperature changes Nominallensile strength Design strength connection in tension Required tensile axial strength for LRFD Required tension strength of connection for LRFD Required tensile axial strength Required tension strength of connection Base stell thickness of any clement or section Thickness of coped web Total thickness of two welded sheets Thickness of thinnest connected part Lesser of depth of penetration and t2 Effective throat dimension of groove weld Thickness of incompressed glass fiber blanket insulation Thickness of stiffener effective throat of weld Based thickness connected with fillet weld Thickness of member in contact with screw head Thickness of member not in contact with screw head Reduction coefficient Required allowable strength for ASD Coefficient of variation of fabrication factor Shear force due to factored loads for LSD factored shear force of connection for LSD Coefficient of variation of material factor Nominal shear strength Coefficient of variation of tested-to.:predicted load ratios Coefficient of variation of load effecl
Will
W" w HI
IV
1'1-;
w.1'
beams and similar section::;; or half distance w,
w" It'l IV]
x x Xo
XQ
x
Y Y, Yo
a a a a
a
between webs for box-or U-type sections Required distributed gravity load supported by the i/h purlin per unit length Out-to-out width Leg of weld Leg of weld Non-dimensional fastener location Nearest distance betwccn web hole and edge of bearing Distance from shear center to centroid along principal x-axis Distance from centroid of flange to shear center of flange Distance from shear plane to centroid of crosssection Yield point of web steel divided by yield point of stiffener steel Gravity load from tile LRFD or 1,6 limes the ASD load combinations applied at level i Y distance from centroid of flange. to shear center of flange Coefficient for purlin directions Coefficient for conversion of units Load factor Coefficient for strength increase due to overhang Coefficient aCCOllnts for the benefit of an unbraced length, L"" shoner than Lo Magni ficatioll factors
jf
jJ fibr, I
Coefficient A value accounting for moment gradient Required brace stiffness for a single compression member Target reliability index th
National Structural Code of the Philippines 6 Edition Volume 1
5·224
CH AP T H i ~)·
St eel and Me tals
Lateral displ:Jcemc lll of purJi n l Op ll ange jlt the line rcslrailll
Coefficient
General Terms
~:",,,,,
St ress gradient in web
APPLICABLE BUILDING CO DE. Building Code un ki th which the structure is dcsigned (i.e NSCP 6 Edition).
Yi
Load factor Angle between web and bC'-Iring surface > 45 " but 11 0 more than 900 Angle between vertical and pJanc of web of Zsection, degrees
()", (~,
y; r;· (I), (° 1
II
II
II" II,
BI,A RING (LOCAL COMPRESSIVE YIELDING). Local co mpressive yielding du e to the action of II member bearing against another member or surface.
Angle of segment of complex lip
A,2,
Slenderness factors
). /. ).1.
Parameters used in dClCrmining compressio n strain
A" A"
F'ICIOT
At A"
Slendcmcss factor
BLOCK SHEAR RUI'TUR E. In a con neclion, Icns ion mptures along one path and shears yieldin g or shear rupture along anothe r path.
Slenderness factor
/'
Poisson's ration for slecl:::0.10
P
Reduction fHelor
0',
BRACED FRAM E. Essentially venical truss system that provides resistance lO lateral loads and provides stability for the structural system.
(rr2E) / (K,L, / r.)' (rr2E) / (I., / ,j (rr2E) / (K,.L,. / r,J' . . 1 (rr2E) / (L / r,.) Torsional buckling Slress
BUCKLING. Sudden change in the geometry of a structure or any of its clements unde r critical loadi ng condition.
Reistancc factor Resistance fac tor bending Resistance factor for conce ntri call y loaded co mpression strengt h Resistance fac lOr fo r diap hragm s Resistance faclor for tensile stre ngth Rcsistance factor for fracture 011 net section Re sistance factor for shear strength Resistallce factor for web crippling st rength I f/Ji I
Parameter for reduced stiffness lISing analysis
fl flb fl,.
n" n, fl,.
n ...
BEARING. In a co nn ection. the ultimate shelr forces transmitted by the mcchanical fastencr to the cv!..1cction c1cments.
sccond ~ order
Safely factor Safety facto r for bending strength [aclor [or concciltricnll y Safety comp rcssion st rcngth Safcty factor for diaphragms Safety [actor for tension strength Snfely factor for shear strength Safety factor for web crippling strcngth
loaded
BUCKLING STRENGTH. instability limits slates.
Nominal
Slrenglit
for
COLD-FORMED STEEL STRUCTURAL MEMBER. Shape manufaclUrcd by press~braking blanks sheared from sheets, cui lengths of coils or plates, or by ro ll forming colelor- hot rolled coils or sheets: both formin g operations bei ng performed at ambient room temperature, thai is, without manifest addi tion of heat such as woul d be required for hot forming. CONFIRMATORY TEST. TeSi made, witen desired, on membcrs, connections, and assemblies designed in accordance with the provisions of Section 551 through Section 557, Appendices 1 and 2, and Section C~3 of this Specification or its specific references, in order to compare actual to calculated performance. CONNECTION. Combination of stru ctural clements and joi nts lIsed to tran smit forces between two or more members. CROSS-SECTIONAL AREA: EFFECTIV E AREA. Effec ti ve area, Ae, calcubted using the effective widths of component elemen ts in accordance with Sec tion 552. If the effective widths of all component clements, determined in accordance with Section 552, arc equal to the actu
Association of Structural Engineers of 1118 f>hili ppines
cakulaled without considering joca! buckling in th e componellt clements, which equals either Ihe gross area or net area, Os applicable.
Gross An::t. Cross area, At, without dcdlH.:lions for hol es, openings and culouts. NET AHEA. Nel area, An, equal of holcs,'opcnings, and ClIlOuts.
10
gross arca less the
FLEXURAL-TORSIONAL BUCKLING. Buckling mode in which a compression member bends
Horizolltal structund member tilm SU ppOJ1s Willi p,mels and is primaril y subjected 10 bending under hOlizontal loads, sllch
arCH
CURTAIN WALL STUD. A member in the steel framed cxterior wall system that transfers transverse (oul-or-plane) loads and is limited to a superimposed axinl load, cxcilJsivc of sheathing materials, of /lot more thllll 1460 N/m, or superimposed axial load of /lot more that 890 N per stud. DIAPHRAGM. Roof, floor, or other membranc or braCing system llulI transfers in -plane forces to the lateral force resisting system. DIRECT STRENGTH METHOD. An alternative design method deHl llcd in Section C-I that provides predictions of member strengths without the usc of effective widths. DISTORTIONAL BUCKLING. A mode of buckling involving change ,in cros s~sec tional shape, excluding local buckling.
DOUBLY-SYMMETRIC SECTION. A section symmetric about two orthogonal axes through its centroid. EFFECTIVE DESIGN WIDTH (EFFECTIVE WIDTH). Flat width of an clement reduced for design purposes, also known simply as the effective width.
IN-PLANE INSTABILITY. Buckling involving in the plime of the frame-or the-member. INSTABILITY. Ultimat e loading of a structural componen1, frame, or strllcture in which a slight disturbance . in the 10(l(ls or geometry produces large displacements. JOINT. Area where two or more ends. surfaces, or edges arc altnched. Categorized by Iype or fastener or weld uscd and the method of force Inlllsfe r. LATERAL-TORSIONAL BUCKLING. Buckling mode of a flexural member involving deflection out of the plane of bending occurring simuhaneolJsly with twist about the shc'll' center of thc cross -section.
LOAD. Force or other action that results from the weight of building materials, occupants and their possessions, ellvironmental effects. differential movemcnt, or restrained dimensi onal changes. Forces, stresses, and defonnations LOAD EFFECT produced in a structural component by applied loads.
FACTORED LOAD. Product of a load factor and the nominal Imld.
Load Factor. Factor that aCCOU!llS for deviation of the nomina! load from the actual load, (or uncertainties in the analysis that transforms the load into a load effect and for the. probability that more than one extreme load will occur simultaneously.
FATIGUK Crack initialion and growth resulting from rereated application of live loads.
LOCAL BENDING. Ultimate state of large deformation of a flange under a concentrated transverse force.
FLANGE OF A SECTION IN BENDING (FLANGE). Flat width of flange including any intermediate stiffeners plus adjoining comers.
LOCAL DUCKLING. Buckling of a compression clement where the line junctions between elements rem ain straight and angles between clements do not change.
FLAT WIDTH. Width of an clement exclusive of corners measured along its plane.
LOCAL YIEL[)ING. Yielding that occurs in a local area oi' all element.
FLAT-WIIlTII-TO THICKNESS RATIO (FLAT WIDTH RATIO) . Flat width of on element measured along its plane, divided by its thickness.
MASTER COIL. One co ntinuous. weld-free coil as produced by a hal mill , cold mill, metallic coating line or paint line and identifiabl e by a unique coil number. In some cases, thi s coil is cut into smaller coils or slit into narrower coils; however. all of these smaller and lor narrower finished coils arc said to have come from the same mast er coil if they arc traceable to the original master coil number.
FLEXURAL BUCKLING. Buckling mode in which a compression members defl ects laterally without a twist or change in cross-sectional shape.
National Structural Code of Ihe Philippines 6'" Edition Volum e 1
~; · 226
CHAI'T E:FI
~)
.
Sl(~cl
and Metal5
MOMENT FRAME. Framing system that pro vides resi stance 10 lateral loads and provides stability 10 th e struct ural sys tem primarily by shear and Ilexure of the fra ming Illcillhers alul thei r cOllllecl ions.
RESISTANCE FAC TOR, q>. Factor that "cco unts for unavoidable deviatiolls of the nominal strength from the tlc!U,l l strength and for the manne r .111<1 COJl Sl·.qIlCllc CS o r fai lure.
MULTII'LE-STIFFENED ELEMENT_ Elemen t stiffened between webs, or between a web and a stiffened edge, by means or intermediate stiffeners parallel to the direction or stress.
RUPTURE STRENGTH. Strength limited by breaking or tcari ng of members or cOllnecting clements.
NOTIONAL LOAD. Virtual load applied in a structural analysis to account for destabilizing effeCls that arc not otherwise accollllIed for in the design provisions. OUT-OF-PLANE IlUCKLlNG. Ultimate state of a beam, column or bea m-column involving lateral or lateraltorsional buc kling. PERFORMANCE TEST. Test made on structural mem bers, coullect ions. and asse mblies whose performance can not be determined in accorda nce wilh Section 551 to Section 557 of this specifica tion or its specific references. PERMANENT LOAD. Load in which variations over tim e arc rare Or of small magnitude. All other loads are variable loads. POINT-SYMM ETRI C SECTION. Section symm etrical about a point (ce ntroid) such as a Z~scc( i on havin g eq ual
flan ges. PUIlLISHED SPECIFICATION. Requiremen ts for a steel listed by a manufacturer, processor. producer, purchaser, or other body. which ( I ) arc generall y available in the public domain or arc available (0 the public upon request, (2) arc
established before the steel is ordered. and (3) as a minimulll, specify Illlnimum mechanical properties, chemical compos iti on lim its. and . if coated sheet. coati ng properties. PURLIN. Horizontal structural member that supports roof deck and is primarily subjected to bending under vCltica l loads such as live. wi nd , or dead loads.
P·A EFFECT. Effect of loads 'Icli ng on the deflected shape of a me mber be tween joints or nodes.
SECOND-ORDER ANALYSIS. Structural analys is in which equilibrium conditions arc formulated on the deformed struct ure; sccond ~ ordc.r crfects (both P-O and P-A, unless specified otherwise) are induded. SECOND-ORI)lm EFFECT. Effect of loads actin g on the deformed configuration of a structure; includes P-O effect and P-Il effect. ~HEAR IlUCKLING. Buckling mode in whi ch a plate e leme nt , suc h as the web of a beam , de forms under pure shcCll" applied in the pl ane of the plate.
SHEAR \VALL. Wall that provides resistallce to late ral loads in the plane of the wall and provid es stability for the structural system . SINGLY-SYMMETRIC SECTION. Sec ti on sym metri c 3bout only one axis through its cenlroi(/. SPECIFIED MINIMUM YIELD STRESSES. Lower limit of yield stresses speci fied for
P- A EFFECT. Efrect of loads actin g on the displ aced location of joints or nodes in a structurc. In tiered building structures, thi s is the effect of loads acting on the laterall y displaced location of floo rs and roofs.
RATIONAL ENGINEERING ANALYSIS. Ana lysi s based on theory th at is appropriate for the situation, an y relevant lest data, jf available, and sound engineeIing judgment.
ANALYSIS.
Dete rmination
of 10';<;
effects on memb ers and co nnections based on princip les oj"
structural mechanics. STRUCTURAL MEMBERS. Sec the definition of (\ : . For med Structural Steel Strllclunli Me mbers STRUCTURAL COMPONENT. Member, connecting clemen t, or assemblage.
Ass ociation of Structural Engineers of the Pililippines
COl" :·
.v,.
SUB-ELEMENT
ELEMENT.
OF
A
MULTIPLE
STIFI'ENED
Port ion of a multipl e stiffened clement
YIELD STRESS. Ge neric term to denote either yield strength, as appropriat e for Ihe material.
between IIdjaccnt inlCJ'lll Cdialc stiITeJ)!'!!"s, bL~Lwccl1 web and
intermediat e stiffener , or between edge ,tilt! inlCnlH:dialc
YIELDING. Lilllit stal e of incias\j(,; deformation that
stiffener .
occ urs whe n the yield st ress is reached.
TENSILE STRENGTH (OF MATERIAL ). Maxim ul11 tensile stress thaI a rn;ncriaJ is capable of sustaining ;t S defined by ASTM.
YIELDING (PLASTIC MOMENT). Yielding Ihroll ghoul the cross section of a member us th e bending mOlll ent reaches the plastic momellt.
TENSION AND SHEAR RUPTURE. in a boll or olher
YIELDING (YIELI) MOMENT). Yield ing allhe cxlreme
type of a mec hani cal fastener, limit slate of rupture du e
fiber 011 the cross secti on of
10
simultan eo us tension and she ar force.
THICKNESS. The thi ckn ess, t. of
Buckling mode wh ich a
compression member twi sts about its shear center axis. UNSTIFFENED COMPRESSION ELEMENTS. FI:ll compress ion ele me nt sti ffe ned ill o nl y O IiC edge parallel to thc directi on of stress . UNSYMMETRIC SECTION.
Secli"n nol symmclric
either about an axis or a poil1t. VARIAULE LOAD, load.
ASD and LRFD Terms ASD (ALLOWAIlLE STRENGTH DESIGN). Melhod of propol1i o ning structu rn l component s sll ch as th at the
allowabl e strength equal s or exceeds the required strength of th e component und er thc action or thc ASD load combi nati ons. ASD LOAI) COMBINATION. Load combin ,"ion in Ihe
appli cable bui lding code intended for al lowable strcngth design (allowable strcss design). Allowabl e Strength . Nominal Strength divided by th e safe ty r'letOJ'. R.,Ifl .
Load nol classi fi ed as permanent A VAILABLE STRENGTH. Desi gn Sirengih or allowa ble
strength as appropriat e. VIRGIN STEEL. Steel as received frolll the steel produce r or warehouse before being cold worked as a result of
fabricating operations.
DESIGN LOAD. Appli ed load del ermined in accord ance with ei ther LRFD load combinations or ASD load
combinatio ns wh ichever is appl icable. VIRGIN STEEL PROPERTIES. Mec hani cal propcni es
of virgin steel such as yi eld elongati on.
stress, tensile strength, and
DESIGN STRENGTH.
Resistance raclOr llluiliplied by
the Iluminai strength, ¢H".
WEB. In a member subjected to flexure, th e portion of the section that is joined to.two flanges, or that is joined to onl y one flange provided it crosses the neutral axi s. WEll CRIPPLING. Loca l failure of we b plate in Ih e immedimc vicinit y of a concentrated load or reaction.
LRFIl
(LOAD
AND
RESISTANCE
FACTOR
DESIGN). Method of proponioning stru ctural component s sllch that the design strength equals ur exceeds the required strength of the component under the action of the LRFD load co mbin ations. LRFD LOAD COMBINATION. Load co mbinal ion ill Ih e
YIELD IVIOMENT. In a me mbcr subjec ted to bending, the moment at which the c xtr(,~ JllC outer fiber first attains th e yield stress.
appli cab le building cod e intended for stre ngth design (Load and Resistance Factor Design).
YIELD POINT. First stress in a materi al at which an
by the applicahle bu ilding ( ode.
NOMINAL LOAD. The ma gllillides or Ihe loads specifie d
increase in strain occ urs without an j-ncrcasc in stress as NOMINAL STRENGTH.
defined by ASTM. YIELD STRENGTIL Sires> "I whi ch a maleri"ls exhibits a specified Iimiling de viation from the propo rtionalit y of s tress to slrain as defined by ASTM.
Strenglh of a slruetllre or
component (without th e resistance facto!' or safety factor applied) to resist the load effects, il S determin ed in accordance with this Specificati on.
th
National Structural Code of the Philippin es 6 Edition Vol ume 1
S··2~~8
CHAPTE ii 5 ~ Siee! and Metals
REQUIRED
STRENGTH.
Force,.
stresses.
and
deformations acting on a gtructural component, determined by either structural analys is, for the J. ... RFD or ASD load combinations , as appropriate, or as specified by this Specincation. RESISTANCE. See the definition of Nominal Strength.
SECTION 551 . .
GlfNERALPRO,VlSI(}NS Thi s see-tion states the scope of the Spcl.:ification, sum marizes refcrenced specification , code, and sHindard doctllllents, and provides requirements for materials
SAFETY FACTOR, U. Factor that accou nts for dev iations of the actual strength, deviati ons of the actual loads from the nominal loads, uncertainties in the analysis that transforms the load into a load effect , and for the manner and consequences of failure.
552
SERVICE LOAD. Load under which serviceability limit
553 554
STRENGTH LIMIT STATE. which the maximum components is reached.
The section is organized as follows:
551
General Provision Elements Members Structural Assemblies <1I1d Systems Connections and Joints
555 556
slales are evaluated.
strength
Limiting condition, in of a
.
Test for Special Cases Design of Cold-Formed Steel Structural members
557
and Connections for Cyclic Loading (Fatigue)
structure or its
55!.! Scope, Applicability and Definitions 551.1.1 SeQl'C This specification applies to the design of stru ct ural members cold-formed to shape from carbon or low-alloy steel sheet, strip, plate, OJ' bar not more than 25 mm in thickness and used for load -carrying purposes in 1.
Buildings; and
2.
Struclurcs othcr than buildings provided allowances are made for dynami c effects.
551.!.2 Applicability Thi s Specification in clud es Symbols and Definitions, Section 551 through Section 557, Section C-I, to Section C3 that shall apply as follows:
Sect ion C- I
Desi gn of Cold-Formed Steel Struct urell Members Using Direct Design Stren glh
Method Seclion
C~2
Section C-3
Second -Order analysis. Addition al Provisions
This Specification includes dcsign provisions for
I.
Allowable Strength Design (AS D), and
2.
Load and Resistance Factor Design (LRFD).
The nominal strength and st iffness of cold-formed steel elements, membcrs, assemblies , connections, and details shall be determined in accordance with the provisions in Section 552 to Section 557. Section C-I to Section C-3 of the Specification. Where
the
composition
Association of Structural Engineers of the Philippines
or
conf"iguralioll
of
such
C HAPTU~
co mponents is such thal calculati o n of strength andlor stiffness cannot be made in accordance with those provisions, struc tural performance shaH be established from either of the following:
J.
Available strength or stiffness by te:m;, undertaken and eva luated in accord iulce ~'ith Section 556,
2.
Ava ilable strength or stiffness by rHtional engineering analysis based on appropriate theory, related testing if data is avail able, and en gineering judgmen t. Specifically, the available strength is determined from the calculated nominal strength by appl yin g the following safet y factors or reSiS1
For Members Q
= 2.00 (ASD)
¢ = 080 (LR FD)
For Connec tions Q = 2.50 (ASD)
5
Si. 00! and Motal
5 ·~229
ASTM A572/A572M, Standa rd Specification for HighStrength Low~Allo y Coiumbiulll- Vanadium Strucllll'
¢ = 0.65 (LRFD)
551.1.3 Definitions In thi s Specification, "shall" is used 10 ex press a In
ASTM A792!A792M. (230 MPa, 255 MPa, 275 MPa, and 340 MPa Class I and Class 4), Standard Specification for Steel Sheet, 55% Alum inum-Zinc Alloy-Coated by the HotDip Process. ASTM A847!A847M, Standard Spccification for ColdFormed Welded and Seamless High Strength, Low Alloy StJ'l\ctllJ'aJ Tubing with Improved Atmospheric Corrosion Res istance ASTM A875/A875M (SS 230 MPa, 255 MPa, 275 MPa. and 340 MPa Class I and 3; HSLAS and HSLAS-F, 340 MPa, 410 MPa, 480 MPa, and 550 MPa) , Standard Specifi cation for Steel Shed, Zinc-5% Aluminum AlloyCoated by the Ho t -Dip Process ASTM A1003/AI003M (ST 340 MPa H, 275 MPa H, 255 MPa H, 230 MPa H), Standard Specification for Steel Sheet, Carbon, Met allic- and Nonmetallic-Coated for ColdFormed Framing Members ASTM AI008/AI008M (SS 170 MPa, 205 Mra, 230 MPa Types I and 2, and 275 MPa Types I and 2; HSLAS Classes I and 2, 3 10 MPa, 340 MPa, 380 MPa, 410 MPa, 450 MPa, and 480 MPa; HSLAS-F 340 MPa. 4 10 MPa, 480 MPa, and 550 MPa), Standard S pecification for Steel, Sheet, Cold-Rolled, Carbon, Structural, High-Strength LowAlloy, High-Strength Low-Alloy with Improved Formab ility, Solution Hardened, and Bake Hardenab le ASTM AJO ll /AIOllM (SS 205 MPa, 230 MPa, 250 MPa T ypes I and 2, 275 MPa, 3 10 MPa, 340 MPa, and 380 MPa ; HSLAS Classes 1 and 2, 310 MPa, 340 MPa, 380 MPa, 410 MPa, 450 MPa, and 480 MPa ;HSLAS-F 340MPa, 410 MPa, 480 MPa, and 550MPa), Standard Specification for Steel, Sheet and Strip, Hot-Rolled , Carbon, Structural, High-S trength Low-AllOY and High-S treng th Low- Alloy
National Structural Coele of tile PhilippinEls
Gt:l
I:':dition VOIUIT1e 1
!
5--230
CHAPTEr:=: 5 - St081 and Metals
strength in Sections 551 to Section is taken as 75 percent of the specified minimum yield stress or 410 MPa, whichever is less, and
with Improved Formability ASTM AI039/AI039M (SS 275 MPa, 340 MPa, 380MPa, 410 MPa, 480 MPa, and 550 MPa), Standard Specification for Steel, Sheet, Hot-Rolled, Carbon, Commercial and Structural, Produced by the Twin-Roll Casting Process. Thicknesses of 380 MPa and higher that do not meet the minimum 10% elongation requirement are limited per Section 551.2.3.2. 551,2,2 Other Steels See Section 551.2.2 of Section C-3 551,2,3 Ductility Steels not listed in Section 551.2.1 and used for structural members and connections in accordance with Seclion 551.2.2 shall comply with ductility requirements in either Section 551.2.3.1 or Section 551.2.3.2: 551,2,3,1 General The ratio of tensile strength to yield stress shall not be less than 1.08, and the total elongation shall not be less than 10 percent for a 50 mm gauge length or 7 percent for a 200mm gaugc length standard specimen tested in accordance with ASTM A370. If these requirements cannot be met, the following criteria shall be satisfied: 1.
Local elongation in a 12.7 mm gauge length across the fracture shall not be less than 20 percent, and
2.
Uniform elongation outside the fracture shall not be less than 3 percent. When material ductility is determined on the basis of the local and uniform elongation criteria, the use of such material shall be restricted to the design of purlins, girts, and curtain wall studs in accordance with Sections 553.3.1 (a), Section 553.3.2, Section 554.6.1, Section 554.6.2, Section 554.6.2a, and requirements given in Section C-3.2.1 of the Section C-3. For purlins, girts, and curtain wall studs subject to combined axial load and bending moment (Section 553.3.5) rJJJIP'1 shall not exceed 0.15 for ASD, P,! ¢,?" shall not exceed 0.15 for LRFD.
Steels conforming to ASTM A653! A653M SS (550 MPa), AIOOSI AI008M SS (550 Mpa), A792/A792M (550 Mpa), A875! A875M SS (550 Mpa), thicknesses of ASTM AI039 Grades (380Mpa), (410 MPa), (480 MPa), and (550MPa) that do not meet the minimum 10 percent elongation requircment in Section 551.2.3.1, and other steels that do not meet the provisions of Section 551.2.3.1 shall be permitted for cOllce11lrically loaded closed box section compression members as given in Exception 2 below and for multiple-web configurations such as roofing, siding, and floor decking as given in Exception 1 provided that: The yield stress,
The tensile strength, Fm used for determining nominal strength in Section 555 is taken as 75 percent of the specified minimum tensile strength or 427 MPa, whichever is less.
Alternatively, the suitability of such steels for any multiweb configuration shall be demonstrated by loads tests in accordance with the provisions of Section 556. Available strengths based on these tests shall not exceed the available strengths calculated in accordance with Section 552 through Section 557, Section C-J to Section C-3, using the specified minimum yield stress, F,·Y' and the specified minimum tensile strength, PI/" Erceplion l: For multiple-web cOI{figuratiol1s, a reduced .specified minimum yield stress, R"Fs )', shall be permitted for determining the nomina! flexural strength in Section 553. 3. la, for which the reductio/1 factor, Rb , shalf be determined in accordance \v;th (a) or (b): a.
For stUTened alld partia!!y sfUTelled compression flanges For
wi! -::;O.067EI F.,), (Eq,551.2-1)
Rb = 1.0 For 0.067 ElF". < wit < 0,974 E I F,y Rb= 1-0,26/1
IV
For 0.974 ElF,)
Fsy I (tE)),O.067/" ~
J"~\"
wll
~
500
Rb= 0.75 b.
For unstllfened compression/langes For wit
~
0.0173 EI F" (Eq. 551.2-2)
lib = J,O
1"01'0.0173 EI F,y
551,2.3.2 Steels
1.
2.
lib = 1.079 - 0.6
used for determining nominal Association of Structural Engineers of the Philippines
< I,vlt ::;60
CHAPT ER 5
Steel and Meta l
5-231
551.4 Allowable Sh'cngth Design w
= :::: :::: ::::
Flat width of compression flange Thickness (~f section Modulus (~r elasticity o/steel ,S'peClfied minimum yield st((~SS determined in accordance ""iill Section 551.6 5.550 MPa.
The above Exception shalJ not appl y to the use of steel deck for com pos ite slabs, fo r which the steel deck acts as the tensile reinforcemenl of slab. EJ:ceptioll 2: For concentrically loaded compression members lVith a closed box section, a reduced yield stress, O.9Fsy, shall be permilfed to be used ill p lace (~f F.\. ill Eqs. 553.4.2, 553.4.3, and 553.4.4 for determining the axial strength in Sec/ion 553.4. A reduced radius of gyration (R,)(r) shall be used in Eq. 553.4.1 when the value of the effective length KL is less than 1.1 La is given by Eq. 551-3, and R,. is given by Eq. 551 -4.
(Eq. 55 1.2-3)
551.4.1 Design Basis Design under thi s section of the Specification shall be based on Specificati ons shal l be based 011 Allowable St rength Des ign (ASD) principles. All provisio ns of thi s Speci l1 cati on shall Hpply, except for those in Sections 551.5 and in Secti on 55 3 and Section 556 designated for LRFD.
551.4.1 a ASD Requirements A design satisfi es rhe req ui rements of this S pecificati o n when the all owable strength of each structural component eq uals or exceeds the requ ired strength, determined on the basis of the nomi nal loads, fo r all appli cable load combinatio ns. The design shall Eq. 55 1.4: I - I:
(Eq. 551.2-4)
I. J Lo
u41ere L"
R,
KL
= Length at wh ich local buckling stress equals jle:rural buckling stress = Radius gyration offull unreduced cross section Minimum critical buckling slress for seClioll ca/cu/aled by £q. 552.2 Reductionjllctor = Effective lenglh
= =
551.2.4 Dclivered Minimum Thickncss T he uncoated min imum steel thi ckness of the cold-formed steel product as delivered to the job site shall not at any location be less than 95 percent of the th ickness ,t, used in its design; however, lesser thicknesses shall be permitted at bends, such as corners, due to cold Mforming effects.
in
accordance with
(Eq.551.4- 1) where
Q
=Req uired strength =Nominal Strength specified in Section 552 through Section 557 and section e-l. =Safety factor specified in Section 552 through
II,,1D
Section 557 and sectio n C· I. = All owable streng th
R II , = 0.65 + O.35( KL)
be performed
RII
551.4.1b Load Combinations for ASD Load combination for AS D shall be as stipulated by Section C-3.3. l. la of Section C-3.
551.5 Load and Resistance Factor Design 551.5.1 Design Basis Design under thi s sec tio n of th e Specifi cation shall be based Load and Resistance Fac(o r Design (LRFD) principles. All provisions of thi s Specification shall appl y except for those in Sections 551.4 anel in Chapters 553 and 556 designated for ASD and LRFD. a ll
551.5.1.1 LRFD Requirelnents A design satisfi es the requ irements of thi s Specification
551.3 Loads Loads and load combinations shall be as stipulated by the appli cable provisions in Section C-3.3 of Section e-3.
when the design strength of each st ructural component equ als or exceeds th e required strength determined on the basis of the nomi nal loads, multiplied by the applicable load factors, for all applicable load combinati ons. The desig n shall be performed in accordance with the Equ ati on 551.5- 1: II" ~~II,, (Eq. 55 1. 5-1) where
Nati onal Structural Code of tile Phili pp ines 6th Edition Vo lume 1
p,;;SY
!)-2~32
CHAPTEB 5 - Steet and Metals
:= Required ~lrcngl h :;; Resistance facIO!" specified in Seelio!) 552 through 557 and Appendix C-! ::;: Nominal slrcngth specified in Section 552 through 557 and Appendix C-l ::;: Design strength
R"
nange flan ge
F r (,
551.7.2 Slrenglh Increase from
Cold
Work
of
r:"I "\'L' : :
I.
for axially loaded cumpression members and flexural members whose proportions arc such that the quantity p for strength determination is uni ty as detcrmined in accordance with Section 552.2 for each of the component clements of the sec tion, the design yield stresses, F)'(f> of the steel ShllII be determined on the basis of oJ~e of the following methods:
a.
Full section Icnsile lesls [see paragraph (a) of Seclion 556.3.11,
b.
Stub columl1 tests [see paragraph (b) of Section 5563.11.
c.
Computed in accordance with Eq. 551.7- 1. J~'II :::: cr~n·
+ ( I -C)
1'~f'S. F,,,.
(5517-1)
where == Average yield stress of full unreduced section of
c
compression members or full flangc sections of flexural members :::: For compression members, rati o of total corner cross- sectional area to total cross-sectional area of full scction; for flexural mcmbers, ratio of tOlal corner cross-sectional area of controlling
tensile yield
~ trcss
or corners.
1.2, Hil :$ 7, and the included
angle <; J 20" .
II
~ 3.69 (1'",11',.,.)-0.819 (F,,,/J.~...)' - 1.79 . (Eq.55U -·1) ::;:: Tcnsile yield stress of virgin steel specified by Section 551.2 or established in accordance with Set ion 556.3.3. ~
Inside bend radiu !;
:::: Thickness of section m
Fit,·
~ 0.192(1',,,11',.,.) - 0.068 (E'1 . 55 1.7-4) = Tcnsile streJ~gth of virgin steel spccified by
Section 551.2 OJ' established in accmdancc with r~\f
Forming. Strength increase from cold work of forming shall be pennittcd by substitutin g Fya for I~\., where I·~·II is the nverage yield stre:;:; of the full section. Such increase shall be limited to Sections 553.2. 553.3. 1 (excluding Section 553.3.1.1 (b)). 553.3.4. 553.3.5, 554.4. and 554.6.1. The limits and methods for detennining F ya shall be in accordance with (a), (b) and (c).
::::lJ,FpJ (N/t)'1I,
Eq . 551.7-2 applies only when
'~.,.
551.7.1 Yield Stress The yield stress llscd in design, I;~. , shall not exceed the spccificd minimum yield stress of steels as listcd in Scclion 55'1.2.2.1 or 5512.3.2, as established in accordance with Section 556, or as increased for cold work of formin g ill Section 551.7.2.
full cross- sect ional area of l:Olllrolling
(liq. 551.7 -2)
SSI.S.lu Load FHctors and Load Combinations fol' LRFD Load factors and load combinations for LRFD shall be stipulatcd by Section C-3.3.1. J b of Scction C-3.
551.7 Yield Stress nnd Strength [ncrea« froll1 Cold Work of Forming
(0
Section 556.3.3. :::: Wei ghted average tensile yi eld stress of nat portions established in accordance with Section 556 .3 .2 or virgin steel yield stress if tests arc not made
2.
For axially loaded tension members, the yield stress of thc steel shall be determined by eithe r method '( I) or method (3) prescribed in paragraph (a) of this sect ion.
3.
The effect of ,my we lding on mechanical propeJ1ies of;:\ member shall be determined on the basis of tests of full section specimens containing, within the gauge length,
such welding as the manufacturer intends to u ~e . Any necessary allowance for slich effect shall be made in the structural use of the member.
551.8 Serviceability A structure shall be designed to perform its required functions during its expected life. Serviceability limit statc~; shall be chosen based on the intended functi on of tbe slructure and shall be ev
American Iron and Steel Inslitute (AISf) , 1]. 1C Connccticut Ave., NW. Washington . DC '20036: AISI S200·07, North American Standard for ColdFormed Steel Framing - General Provisions AlSI 5210-07, North American Standard for ColdFormed - Floor and Roof System Design
Associalion of Slruclural Engineers of Ihe Philippines
AISI S211-07, North Aillerican Standard for ColdFormed Steel Framing - Wall Stud Design
AISI S212-07, North American for Cold-Formed Sleel Framing - Header Design
AISI S214-07, North American Standard for CoJdFormed Steel Praming- Truss Design AISI S901-02*, Rotational Lateral Stiffness Test Method for BcanHo- Panel Assemblies AISI S902-02, Stub-Coluilln Test Method for Effective Area of Cold-Formed Steel Columns
ASTM A490M-04a, Standard Specification for High Strength Steel Bolts, Classes 10.9 and 10.9.3, for Structural Steel Joints [Metric] ASTM A500-03a, Standard Speci lieation for Cold FOJ'n)ed Welded and Seamless Carbon Steel Structural Tubing in Rounds and Shapes ASTM A529/A529M-05, Standard Specification for High Strength Carbon-Manganese Steel of Structural Quality
Note: * A/5;/ {est procedures previously designated as 7:)!I-XX are reo-designated to A/SI S9n-x).,:, where "/1" is flU' (eSf procedure sequence number and "xx" is tlw year the standard was dcwdoped or updated.
and Alloy Steel Nuts
American Society of Mechanical Engineers (ASME), 1828 L Strret, NW, Washington, Dc 20036:
ASTM A563-04, Standard Specification for Carbon ASTM A563M-04, Standard Specification for Carbon and Alloy Steel Nuts IMetric)
Surface
ASTM A572/A572M .. 06, Standard Specificatiun fur High -Strength Low Alloy Columbium-Vanadium Structural Steel
American Society for Testing and Materials (ASTM), 100 Barr Harbour Drive, West Conshohocken, Pennsylvania 19428-2959:
ASTM A588 I A588M-05, Standard Specification for High- Strength Low Alloy Structural Steel with 50 ksi 1345 Mra) Minimun Yield Point to 4-in. IIOOmm) Thick
ASME B46.1-2000, Surface Roughness, \Vavincss, and Lay 3.
ASTM A490-06, Standard Spc...:ification for Structural Bolts, Alloy Steel, Hcat Treatcd, 150 ksi Minimuin Tensile Strength
AISI S906-04, Standard Procedures for Panel and Anchor Structural Tests
A/Sf
2.
Usc.
Texture,
ASTM A361 A36rn-05, Standard Specification for Carbon Structural Steel ASTM AI94/A 194M-06, Standard Specification for Carbon and Alluy Steel Nuts for Bolts for High . Pressure and High~Tempcraturc Scrvice, or Both ASTM A2421 A242 M-04el, Standard Specification for High-Strength Low-Alloy Structural Steel ASTM A307-04, Standard Specification for Carbon Steel Bolts and Studs, 60,000 PSI Tensile Strength ASTM A325-06, Standard Specification for Structural Bolts, Steel, I-leat Treated, 120/105 ksi Minimum Tcnsile Strength ASTM A325M-05, Standard Specification for Structural Bolts, Steel, Heat Treated, 830 MPa Minimum Tcnsile Strength [Metric] ASTM A354-04, Standard Specification For Quenched and Tempered Alloy Steel Bolts, Studs, and Other Extcrnaslly Threaded Fasteners
ASTM A606-04, standard Specification for Steel, Sheet and Strip, High-Strength, Low alloy, lIot- Rolled and Colel- Rolled, with Improved Atmospheric Corrosion Resistance ASTM A6531 A653M-06, Standard Specification for Steel Sheet, Zinc··Coatcd (Galvanized) or Zinc>Iron Alloy-Coated (Galvannealed) by the l'lot-Dip Process ASTM A847 I A847M-05, Standard Specification j()r Cold Formed Welded and Seamless High Strength, Low alloy Structural Tubing with Improved Atmospheric Corrosion Resistance ASTM AS75 I A875M-05, Standard Specification for Steel Sheet, Zinc-5% Aluminum Alloy- Coated by the Hot-Dip Process ASTM A I 0031 A I 003M-05, Standard Specification for Steel Sheet, Carbon, Metallic-and NOll MetallicCoated for Colel Formed Framing Membcrs
ASTM A370-05, Standard Specifications for Standard Test Methods and Definitions for Mechanical Testing of Steel Products
ASTM A100S1 A IOOSM-05b, Standard Specification for Steel, Sheet, Cold- Roiled, Carbon, Structural, I-ligh- Strength Low Alloy, High- Strength Low Alloy with Improved Formability, Solution Hardened, and Bake Hardenable
ASTM A449-04b, Standard Specification for Hex Cap Screws, Bolts, and Studs, Steel, I-leat Treated, 120/1 05/90 ksi Minimum Tensile Strength, General
ASTM AIOIIlAIOIIM-05a, Standard Specification for Steel, Sheet and Strip, Hot-Rolled, Carbon, Structural, High-Strength Low Alloy and High Strength Low alloy tll
National Structural CodG of the Philippines 6 Edition Volume 1
5·292
CIiA P lE H ~) ·
Steel ami Meta l!;
where A1 db
"
:::
Net tensi Ie area
::: Nomi nal diameter (body or shrank di ameter) ::: Pitch (mill per thread for SI unit s)
557.5 Special Fabrication RC
10
cycl ic siress ran ges sh ... 11 have a 11111 in accord ance with
surface roughness not to exceed 25 ASME 1346. )
Re ~entrant co rners at cuts, copes, and weld Hccess ho les shall form a radius of not less than 10 mm by pre-drilling or sub-p ul\ chin g and reaming a hole, or by t!l enni!! cutting to forlll th e rad ius of the cut. If the radius porti on is form ed is formed by thermal cutting, the cut surface 511(111 be gro und to a bri ght metal contour to provide a radiu sed transition, free of notches, with a surface roughn ess not to exceed /lot to exceed 25 liI1l in accordance with ASME 846. I or anoth er cquivalent approved standards.
For transverse bUll joint s in regions of hi gh tensile st ress, we ld tabs shall be used to provide for cascadin g the we ld tcrmination outside the fini shed j oint End da ms shall not be used. Weld tabs shall be removed and (he end of the weld fini shed flush with the cdge of the member. !;.):ceptioll
Weld tabs shall no! be requiredfor sheer material iJthe weldiflg procedures used result ill smoOlh, flush edges.
SECTION C-l DESIGN OF '"'v'......,.-J.' v ..... ~.''"'v. STRUCTURALC ' ~~~~~ THE DIRECT Si C~l Design of Cold·Formed Steel Struc;,turClJ Members Using (he Direct Strength Method
C-I.I. GcncrClJ Provisions C-l.l.l Applicability The prov isions of this Secti on shall be permitted 10 bc used ( 0 del ermine the nominal Hxial (P,,) .md fl ex ural (Mil) sire ligths of cold·formcd stecl 1l1cmbcrs. Sections C. I.2.1 ,1Ild C. 1.2.2 prcscnt a mcthod appli cable to all cold·fonned steel colu mns and bc.uns. Those members meeting the gcomct ric and IllClterial limitati ons of Secti on C. I. I.I.I for columns and Section C. J. 1. 1.2 for beams have been prequatificd for usc, and the calibrntcd safety factor, D, and resistance facwr, ¢, given in C.1.2. 1 and C. 1.2.2 shall be pcrmi[{ed to apply. Th e usc of the provisions of Section C.!.2.! and C. J .2.2 for other colullIlls and beams shall be permitted, but the standard Q and ¢ factors for ration.a} engineering analysis (Section AJ.2 (b) of. the. main Specification) apply. The main Ame.rican SpeclficatlOll for the Design of Cold· Formed Steel Structural Members.
Currentl y, the Direc t Strength Method prov id e~ no cxpl~ ci t provisions for membe rs in tension, shcar, com bmed bendm g and she'lI", web crippling, co mbined bending and web crippli ng, or combined ax ia l load and bendin g ( beam~ colum ns). Fun her, nO provisions arc given for structura l assc mblic!) or conn ecti ons
Association of Stru ctural Engineers of tile fJhilippin es
CHAP IT. n
I.
app lirable provi siolls of 1I~c. main Spccificllt ion shall he follo w ( ~ cI whelllh,~y f'XiSI ,
2.
;lIld
in cn!
C. J .1.1 ,iI Prc-
Unperformed columns that fall within [hc geometric and material limitations given in Table C-l ~:hall be permitlcd 10 be design cd using the safe ty factor, il, and resistancc faclor. ¢, defined in Section C. 1.2. I. c.1.1.1 b Prc-qllalilicd Beallls
Un perforated bca ms Ihal rail wi lhin the geomctric and marcritll limitations gi ven in Table C-2 shall he pennillcd to be designcd using (he s;lrety ractor. il, ~II}(I resistance faclor, ¢, de fined in Secti on C.1.2.2. C.1.1.2 Elastic Buckling
Analysi s shall be uscd for the determination of th e clastic buckling loads and/or moments used in this Appendix. For columns, this includes the local, distortional, and overall buckling loads (P,.,.(, Pnd , and P('f(" of Section C.!.2.!). For beams, this includes the local, distortional, and overall buckling moments (Ma (. Mm/, and Mat of Section C. ! .2.2). In some cases, for a given column or beam, al! three modes do not exist. In such cases, the non-existent mode shall be igno red in the calculations of Sections C.1.2.1 and C.1.2.2. The commentary {Q this Appendix provides guidance 011 appropriate anal ys is procedures ror clasti c buckling dctcnninatio n.
M ct~li
S·29:.J
C. I.2.1 Column Design The nominal axial sirength jresisia/lce ]. fJ'l> shall be the minimum of P"''' Fill, and Pm/ as gi vcn in Sec.tions C.l.2.1.1 to C. 1.2.1.3. For columns mceting the geometric and material criteria or Section C.1.l.!
(ASD)
$, = 0.85
(I,RFD)
For all other columns, Q and ¢ of [he main Specification, Section 55! .1.2(b), shall appl y. The :lVailablc strength shall be dctermined in accordance with applic"ablc mcthod in Section 551.4 . or 551 .5 of the main Speci fi cation. C.I.l.I .. Flexunll, Torsinllal, or FlexurnI-Torsional Buckling The Ilomina! axial strength, PIll"~ for flex ural, torsiona!, or Oexural -torsiona! buckling shall be cidculatcd in accord.mcl' with the following: For",~1.5
(aJ
I~"
=(0.658),;
y>,
(Eq. C.1-2)
For I"~ ~ 1.5
(b)
p III'
=(0.877)1' ...t;
(Eq. C.1-3)
.I"
where (Eq. CI-4)
(Eq. C. I . I)
where
P,. Pm
where
M
SlOe! and
C. 1.2 Members
C. I.t.3 Serviceability Determination
The hending deflection at any moment, M, due to Ilominnl loads shall be pcrmiltcd to be determined by reducing the gross moment of inertia, I g , to an effective momcnt or inertia fOf deOeclioll, as given in Eq. C.l- L
Md
~~
::;:; Nomina! ncxural strength, M'I! defined in Section C.1.2.2, but with M,. replaced by M in all equations or Section C. (2.2 =:: Momcnt du e to nominal loads on membe r 10 be conside.red (M ~ My)
A,F,. (Eq. C.I-S) = Minimum of the critical elastic column buckling load in flexural, torsional , or flexural-torsional buckling determined by analysis in accordance with Section C.1.1.2.
=
c.J.l.l b Local Buckling The no minal axial strength, Pur, for local buc kling shall be calcu lated in acco rdance with the following: • I.
For AI S 0.776
(Eq. C. 1-6)
(E'I. C.1-7)
th
National Structural Code of the Pililippines 6 Edition Volume 1
s·?ut)
CH AP TUl
~i
. Sl eel
;}llcj M (~ I,I I S
For 2.78 M,. i: M, .. ? O. 56M,
2.
wh crt'.
;~::'" ~ J----I~'rt
M
(Eq. C 1-8)
= A valu e as defined in Secti on C. J .2. ).1 = Critical clastic local column buckling lo,ld determin ed by analys is in accordance with Secli oll C. 1.1.2
:1.
L~ M <)
(E'I. C I - IO)
where
36 M or
(Eq. C. I-I.1)
~
CEq. C. 1-14)
where ;;;: Criti cal clasti c lateral-torsional buckling momCn t determined by anal ys is in accordance wilh Secti on C. ! .1.2 (Eq. CI-15) where
-Sf
= Gross section modulus referenced fiber ill first yield
For J." > 0.561
I~", ~ [1- 0 21.JI~~ )0."](.!;~.!!.. )".<, P,
[I. .~.A::. -:._ ')
A1,,,. = A1,.
Thc nominal axi Hi strength, Pili" for distortional buck ling shall be calculated in accordance with the followin g:
(10'1 _CI-9)
Y
For M,.... > 2_78 M ,.
M,.".
CI.2.! c ()jstortional Buckling
2.
'0 1/,'
(O
the extreme
C.1.2.2h Local Buckling The nomin al flex 1I 1'<1 I sl re ngth, M.". for local buckling shall he calculated in accordance wil h the following: 1.
For /..( S 0. 776 (Eq . C. 1-16)
(Eq. C I - II)
2.
Fod, > 0_776
where Py Pml
= A valu e as given in Eq . C. 1-5 ::;;: Critical clastic distorti onal column bucklin g load determi ned by anal ysis in accordance wi th Section C. 1.1.2.
Mill
(ASD)
Specifi cation.
l.
For Mm < O.56M.I'
)"-') (_':!
crt.
M ,W
)"-'
M ne
, -. JM,~
11.-1 ...-
(10'1. C. l-IS)
---M a l
= A val ue as defined jn Section C.1 .2.2. 1 ;:;: Criti cal elastic local bucklin g mome nt determined by analysis in accordance with Scctioll C I.1.2 C.l .2.2c Distortional Buckling The nominal fl exural strength , Mm/, for distortion:l l budl i shall be calculated in accordance with the followil1 g: I.
C.1.2.2a La(cral~Tor s ional Buckling Th e nominal nexural strength, M ilt' . for lateral-torsional buckling shall be. cal culated in a CCOrd
1- 0. 15 M crt. Mflt'
where
¢,= 0.90 (LRFD)
For all other beams, Q and ¢ of th e main Speci fi cati on, Sec tion 55 I. 1.2.(b), shall appl y. 111e a vai lable st rength [factored resista nce] shall be de te rm ined in accordallce wi th appl icable meth od in Section 55 1.4, or 551.5 of th e main
[ [
0" 1. CI- 17)
C.1.2.2 Bealll Design The nominal flexural strength, M,,, shall be the minimum of M ilt'. MII { . and Mud as given in Section s C. 1.2.2. 1 to C . 1.2.2.3. for beams meeting th e geometric and mat ena l crite ria of Section C. 1.1.1.2, 0 " and ¢, shall be as foll ows: O,~1.67
=:
For ),,, S 0 .67 :\
(6'1 . CI· !'))
2.
For 2" > 0 .673
M
lUI
:::: 1-0.2
(
{
Mad
M
(Eq. C. 1-12)
Association of Structura l Engineers of the Phil ippines
)'
"'5J(MM J0.5 M .I. J Cf d
J
(10'1 . C. J·20)
where
(10'1. <:. 1-21 )
M.. M,.,,,
= A value as given in Eq. C.1.2.2"4
= Critical clastic distortional buckling moment
determined by analysis in accordan ce with Sectioo C I.I.2
National" Struclural Code of the Philippines G'" Edition Volum e 1
~) ' 296
CHAPTEI1
!j .
Steel and Metats
Table C- I
LIInb Icf ~ CoI\IIMW. For aU C_
Upped C..s.ctio .... Simpl" lipo : I<- .. ....,
r
P."
~
1)-
1
90"
..
> 340 Ify < 86 bI (593 MY. or (,o()!lO i<8/
'*
Complex Lips:
~) I.
0,
.1
Lipped C.secoon with Web Stiff.,.,.".(.)
~t<:
34 D;j~< 1 N~
.) Ih is permill>ed 10 .....ry (D" lip i!I penni1kd in ""Sic inw..nt outwml, etc.) ollh I.s IX'mllttoo to vary iDlllp Is oormdtted to ahcle lID, down.. etcOt Far .OC'U! or two intamcduk- ltifienars.: hoIl < 4Il9
Io-~-i
fC
l-&>ctkmf!U(~
T
b,,/t <: lW 6 < 0/1 <33 1.3 < hoIb" -< 2.7 0.05 ~ Olt.., < Q.l
"IFy> 340 IPT < 86 bj (593 MI'. OT «Y.iO i<8/
bolt <: 56 O
1.5 < hoIbo « 1.7
J
0.00
<:
01 b" '" 0.73
". W'
6ff, > 590 If,. <: 50 ~ (J.45 MY. or .352t11os/cm')1
Rack Uprlgftt
rC!~~
See C-5octian with Compb Lips
Hili
n..JI < 51)
i
r T
1'" N04~ :
bzl<-
b,
i'-
fO
...
~.- - ~
..
b,,/ t ""i!!IJ- t{!; < 0/1 < (, 1.0 <: I\,jb. <: 1.2
~
D/I;,,· {).n E/Fy > nil !F~ <: ~ hi {476 Mf'lI <)I' ~'I(I ~/" - C7Vef'OJl "'idth; D ...,.'/ol r.'IJ.*"ta<; ""
Association of Struclural Engineers of Ihe Philippines
._.1 M
eovertll deplf'
Table C·2
c-sectJoru stmple Ufl'$; I--
For .U C·sectklos hoIl < 321
-oj
boft<75
~
r
........
0<0/1<34 1.5 < ho/bo " 17.0
I\,
0" 0lb" "0.10
lL-......Jt
44'" e" 9Ir B/Fr " 421 /F y < 70 bi (483 Mr. oc 4920 kg! em1 )] For C~OT6 with complex
lips:
OYI<: 34
Complex Ups ;
DlID" 2 D:3/1" 34 D:3/Dl" 1 Note: a) Ih 1$ permitted to VAry (D, lip i. pt!fIIlittrd to .ngle inward or outward) b e., is Upped C-S«tJons with Wtb Stiffener 1<-""-1
~
,.r
h,,/1
14 <: D!t < 17 5,S" 1>0/1>0 <: 11.7 027 < D/bD < 0,56
oz
1 ~
9(t'
E/Fy "578 (Fy "51 ksi (352 MPa or 3590 kgleml)] For all z..-:ti0IlB: hoi I < 183 boll" n
Z-Sectiono
Simple Ups;
~
10" 011 < 16 2.5 < hoIb" < • •1
0.15 « 0/1>0 '" 0.34 36< < 0 < 90" E/Fy" 440 [Fy < 67 ktil (462 Ml'lI or 4710 k8l="H For Z-sect:ioo<) with wrnplex lips;
Dz/I <: 34
Complex Lips:
~ b,
t
L
0
0, G,
I.
oyO<: 2
D:3/t < 34 D:l/Dl < 1
&,
0,
.1
National Stru ctural Cod e of the PI1ilippines 6'" Edition Volume 1
Umltatlons for ~WlltfIed aaaIM (COntInued) ho/l<97 bolt < 467 O
Hats (Decks) with Stiffened F1al18" in Compression
A fh,
0.14 < ho/bo < 0.87 0.88 < bo/hj < 5.4 0< n ~ 4 (n = Number of compression Ilange stiffeners) E/Fy > 492 [Fy < 60 ksi (414 MFa or 4220 kg/cm')]
t
"';1:\1+-
Trapezoids (Decks) with Stiffened Flange in Compression
r-b'i
t
~ I+-
.J
b,-+i T
~
ho/I < 203 boll < 231 0.42 < (ho/.tne)/bo < 1.91 1.10 < bo/b, < 3.38 0< I\: ~ 2 (I\: ':' Number of compression flange stiffeners) Number of web stiffeners and/or folds)
o < nw S 2 (nw -
0< "t S 2 (nt· Number of tension flange stiffeners) 52' < 9 < 84' (9 = Angle between web and horizontal plane) E/Fy > 310 [Fy < 95 ksi (655 MFa or 6680 kg/em'»)
Note: r I I < 10, where r is the centerline bend radius. See Section 1.1.1.1 for definitions of other variables given in Table 1.1.1-2
Association of Structural Engineers of tile Philippines
SECTION <:;~~ . SECOND·
P,
This Scclion C.2 addresses second-order an til ys is for stru c tural systems comprised of moment fram es, braced frames, shear wa!ls, or combinations thereof.
u
C.2.! General Rcquil'cmcnL'j
Members shall salisfy the provisions of Section 553.5 with th e nominal COIIlI11I1 strengths Inominal axial rc:-;istanccj,
Pn, determ ined usin g K~ and Xx = 1.0 , as well as (,l X= 1.0 , ay= 1.0, e".. = 1.0. iHld e m .l .= 1.0. The required strengths Ifaclored forces and moments) for Il1clnbcrs. con nections,
nlld other structural clements shall be determined llsing a sccond~ordcr analysis as specified in this Sectio]). All co mponent and connection deformations that co ntribute to the lateral displacclllcn! of the structure shall be co nsidered in the t.lnalysis.
;:: Required axial co mpressive strength Ifactored ;!xiai n)lllpressivc force], (N) :.:. : Member yield slrenglh (;AF\., where A is the fuJI unreduced cross-sec ti onal are a), (N) = 1.6 (ASD) ~ 1.0 (LRFD)
III (;!ses where llexibilit y of other structural componcllts such as connections, fl exible column base dctails. or l1orizo!\wl trusses acting as diaphragms is modeled explicitly ill the analysis. thc stii'fnesscs of th e other st ruc tura l co mponent s sllall be reduced by a factor of 0.8. If notio nal loads arc used. ill li eu of using rb < 1.0 where > 0.5. rb = 1.0 shall be pcnnit(ed to be lIsed for all members. provided that all Hddi tional notional load of O.OO! Yi is "dded to the noti onal load rcquircd in Section C.2.2.4. (~P/Pr
<:'2.2.4 Nolionallonds
C.2.2 Design and Am'lysis Constraints
Noti onall o,lds shall be appli ed 10 the latera l framing system ,H:count for the effects of geometric imperfecti ons. Notional loads arc lateral load s that arc applied al each framing level and specificd in terms of the gravity loads applied al that level. The gravity load used to determine the notional load shall be equal to or greater than the gravity load associated with the l()ad co mbination being eva!u~ted. Noti onal loads shal l be applied in the direction th at add s 10 the destabili zing effects under the specilied load co mbinatioll . 10
C.2.2.l General The second-order analysis shall consider both the effec t of loads acting on the deflected shape of a member between joints or nodes (P-& effects) and the effect or loud s acting on the displaced location of joints or nodcs in a structurc·(P-6 effec ts ). It shall be permitted to perform fhe anal ys is using any general sccond-order amllysis mct hod . Anal yses shall b(~ conducted accordin g to the design and loading requirements specified in Section 551. For the ASD, the second-order analysis shall be carried out under 1.6 times th e ASD load combinations and the results shall be divided hy 1.6 to obtain th e required strengths at allowable load levels.
A notional load, N; = (1/240) Yi • shall be appl icd independe ntly in two o[1hogonal directions as a lateral load in all load combinations. Thi s load shall be in addition to other latcral IOlHis, if any.
Ni
C2.2.2 Types of Aunlysis
Yi
It shall be permissible to carry out the second-order analysis either on the out-or-plumb geometry without noti onal loads or on the plumb geometry by appJying notional loads or minimum latera! loads as defined in Section C.2.2.4.
For second-order clastic analysis, axial and fl ex ural stiffness shall be reduced as specified in Section C.2.2.3.
= Notionallntcrnl load applied at level I, kips (N) ; Gravity load from the LRFD load combination or i .6limes the J\ SD load combinati on applied at level I, N
The notional load coefficien t of 11240 is based on an assumed initial story ou t ~of-pluIl1bness ratio of 1/240. Where a differcnt assumed out - of~ plumbness is justified , thc notionnl load coefficient shall be pcnniHco to be (l(lj usted proportionally to a value not less tha n 11500.
C.2.2.3 Reduced Axial , and Flexural Stifrnes"" Flexural and axial stiffness shall be. reduced by using E*· in place of E as follows for a!1 members whose flexural and axi~1 stiffncsscs arc co nsidered to contribut e to the lateral stability of the. structure:
E*
= O.8rbE
(Eq. C2-1)
where
rb
= 1.0 for 0"1'11',·:0 0.5 =4[0"1'11',.11 - ·al'll',.!] for 0.1',11',. > 0.5 National Structura l Code of the Pllilippilles 6[h Edition Volume 1
fj ·300
C H I\PTH~
!i . Steel and Metals
This Section provides .design provisions or supplements to Secti on 551 through 557. C.3.1 Scope Designs .~:!;:. Jl be made in accordance with the provi sions for Load and Resistance FaClOr Design, or with the provisions for Allowable Strength Design.
C.3.2.1 Ductility In seismic design ca tegory I), E or F (as defined by I\SCEJSEI 7), when materi al du ctility is dl:te rmin cd on the basis of the local and uniform elo ngation cri teria of Section C.3.3.I, cllrtain wall studs shall be limited to the dead load of the curtain wall assem bly divided by it s surface area, but no greater tllilll O.75kN/m 2 . C.3.3 Loads C .3.3.1 Nominal Loads
C.3.2 Olher Sleels
The nominal loads shall be as stipul atcd by the appli cable
The listi ng in Section C.3.1 shall not ex.cl ude the use of steel up to ,\11<1 including 25 mill in thickness, ordered or produced to othe r than the listed specifications. provided the following rcq uireme lli s arc me l:
I.
2.
The steel shall conform 10 (he chelllical and meciwnic(ll requi remcnt s of one of the listed specifications or othcr publ ished specification. The che mica! and mechanical properti es shall be determincd by the producer, the su pplier. or the purchaser, in accordance with the foll owing specifications. For coated sheets, ASTM A9241 A924M; for hal-rolled or cold-rolled sheel lind slrip. ASTM AS681 A568M: for plate and bar. ASTM A61 A6M; for hollow structural sections, sllch tes ts shall be nwcJc in accord ance with tlie requireme nt s of" A500 (for c
J.
The coating propcrl ies of coated sheet shall be de tc lill iue Li b y Ille I'rUf.Juccr, lilt.' suppl ier. or the pu rchaser, ill accordance wilh ASTM A924/ A924M.
.L
The steel shall meet the req uireme nts of Secli n!) C.3.3.
5.
If the steel is to be \VeldC"~l. its suitability for th e intended we lding process shall be established by the produce.l". the supplier, or the purch
building code under wh ich the Slnlcturc is designed or as di ctated by the co nditi ons in volved . In (he absence of a building code, the nominal loads Shlill be those stipulated in the ASCEISEI 7. C.3.3.l.1a Load Combinations for ASD The structure and its components shall be designed so that the allowable strengths equal or exceed the effects of the nominal loads and load combinations as stipulated by the applicable building code under which the structure is designed or, in the absence of an applicable building code, as slipulated in Ihe ASCE/SEI 7. C.3.3.1.1b Load Factors and Load Combinations for
LRFD The structure and its co mponent s shall be de signed so that des ign strengths eq ual or excced the effects or the factored loads and lond co mbinatioll s stipu lated by the applicable building code under which the structure is designed or, in the absence of an a ppli c ab le building code. as stipulat ed in Ihe ASCE/SEI 7 . C.3.4 Referenced Documents The, following document s are rercrefl(~ed in Section C-3:
I.
American Inslilule of Sleel ConstlUclion (AISC), One Easl Wacker Drive. Suite 700. Chi cago, Illinois 606011802: ANSI! AISC 360-05. Specificalion for Siruciural Steel Buildings
2.
Amcrican Iron and Steel inslitutc (A ISI), 1140 ConnecliclIl Avenue. NW, Washin gton, DC 20036:
If th e idenlificalion lind documentalion of Ihe producli on of Ihl! sled have not heen established , th e ll in addition to rcquirC!l1lmts (I) through (5), the manufacturer of the cold· formed steel product shall establi sh that the yield stress and t(:'lls il ~ strength of the IlHlstcr coi l
than
sJJL'Cilicd
III
the
rcf"e rcm:cd
AISI S211-07 . North Ameri can Siandard for Coldrormed S Ie!.! I pmming - Lateral Design A ISI S908·04, Base Test Method fo r Purlins Supporti ng a standing Sea m Roof Systcm
pu blis hcd
s p~ ,.: i fi~·ali on.
3.
Amcrica n Sociely of Civil Engineers (ASCE), 1801 Alexande r J3ell Dri ve, Reston VA, 20191: ASCE/SEI 7-05. Minimum Design Loads in Bui ldings and Other Structures
C HAP 1T H
4.
Vole/din g Code-Sheet Stee l A WS C I.I /CI. I M-2000,
sec tion. The safel y fa..-wr ,HI d th e resistance ra<: lOr prov id ed in this section shall be applied to the nomina! strength. M". calculated by r~l. 554 .6.1.2-1 10 determine the availab le strengths ill accorda nce with the appli cli ble method ill Scclion 551 .4 or 55 1.5.
Res istance Weld ing
C.3.S Tension Members strength, 1;" shall be the smallest value obtained in accordance with the limit States oj" (a). (b) and (c). Unless otherwise specified. Ihe corresponding safety faclOr am.! the rcsislancc faclor provided in thi s section shall be lIsed to determine the available strengths in accordance with (he applicable method in Section 551.4 or 551.5.
0,= 167 (ASD)
¢= 0.90 (LRFD)
:::: Nominal strength of member when loaded il; tensi on :;;: Gross arc a of cross section :::: Design yield su·css as de lermined in accord ance with Section 55 1.7. 1 r 'Of
q,,,=0.90
(ASD)
. ; ..
(LRFD)
where = Reduction factor determin ed in accordance with AISI S908
R
See Section 553.3.1. I for definitions of S,. and F.r-
Flange Fastened 10 a Standing Scum Roof These prov isions shall apply to Z-scctiOllS <:oncentrica!ly loaded along their longitudinal axi s, with -only one flange
rupture in net secti on away from connection (Eq. C3·2)
0,= 2.00 (ASD)
1,= 0.75
(LRFD)
where
3.
Q,,=1.67
C.3_6_2 Compression of Z-Section Members Having One
where
F"
(Eq . CJ·:!)
For yielding in gross sectio n
(Eq . C3·1)
A"
:)·30 1
discrete point bracing and thl! provis ions of Secti on 553.3. 1.2. 1. o r shall be c.:;:llculatcd in "Iccordance with thi s
For axially loaded tension members, the nominal tensile
2.
Slee l and Metal
Amcrican Welding Sodcty (AWS ), 550 N.W . I...cJcunc Road, Miami , Florida 33 J 35:A WS D 1.3-98, Sl l"ucltJral RCcolllllwnucd Practices for
I.
~
= Net area of cross section
= Tensile strength as specified in eilher Section SS 1.2 . 1 or SS 1.2.3.2
The nominal axial strength of simple span or continuous Zsec tions sh all be calcul :lted in acco rdance with (a) and (b ). Unless otherwise specified, the safety fa<:lor and the resistance factor provided in thi s section shall be used to de tcnninc the available strengthS in accordance with the applicable method in Section 551.4 or 551.5. J.
For weak axis available strength (Eq. C.3·4)
For rupture in net section at connection
The available tensile strength shall also be limited by Sections 555.2.7, 555.3, and 555.5 for tellsion members using welded connections, bolted connections. and screw connections.
Q= 1.80 (ASD)
¢= 0.85(LRFD)
where
For dlt ::; 90 ko/ = 0.36
C.3.6 Light-Frame Steel Construction In ;]ddilion 10 th e cold-formed steel framing standards lisled in Section 554.4. Ihe followin g standard shall be followed,
b.
~
2501
0/
Light-framed shear wall s, diagona l strap bracing (lilat is p;'1rt of a structural w,l ll) and diaph ragms to resist wind. seismi c and other in-plane lat eral loads sha! 1 be designed in
C.3.6.l Flexural Meml>ers Having One Flange Fastened to a Standing Scam Roof System The available flexural strength of a C- or Z-section, loaded in a plane parallel to the web with the top flange supporting a standing seam rooC system shall be determined llsing
130
d k = 0.72 - --
as applicable:
1.
For 90 « lit
c.
(Eq. C.3·5)
For til t > D O k,,j= 0.20
R
:::: Reduction factor determined from uplift tests
A
= Full unreduced cross-sectional area of Z-scctioll. = Z-section depth
performed usi ng AISI S908 d
= Z-scction thickness. See Section 553.3.1.1 for definition of F,..
National Stru ctural Code of tile PI1ilippines 6
th
Edition Volume 1
~5·30~
C Hfl. I:>TE:li 5 SlO el and Metals
Eq. 554.6. J -4-1 shall be limited to roof sysle mg mccling the
C.3.7 Welded Connections
fo llowing con d itions:
Welded l.:on ncclions in whic h Ihe lh i {.· knc ~s of Ilw Ihinncst
Purlin th ickness, I.:n mill :::; ,::: ).22 mill
b.
150 mm ::; d ::; 300 111111
c.
Flimges arc edge stiffened compression clemcnts
Except as muddicd herein, arc clds
d.
70 "" dlt Oo 170
c.
2.8 S d / b < 5, where b= Z section flange width.
one of the the con nected parts is 5 mm or less ill th ic kn ess shall be made in accordance wi th AWS D1 3. Welders and weldi ng procedures shall e qualified as specified in AWS
flange flnr width
wilh ANSJlII ISC·360.
I6 5
g.
OOl h flanges arc prevented from moving hltcrall y at the supports
h.
Yield stress,
2.
The available s trength about the strong axis shall be determined in acco rdance with Section 553.4.1 and
t
1'~\. :5 483
< 50
steel where at Icas!
D 1.3. These provisions arc intended to co ver the welding
Res istance welds shall be made in conformance wit h the procedures given in AWS C I .I or AWS CIJ . Tabl e C.3·1
MPa
Welding
553.4.1.1.
' - '- -
In addition to the provisions pro vided in Section 554.6.2. 1.
for load combinations that include wind uplift, the nominal wind load shall be peflnitl ed 10 be multiplied by 0.67 ·provided the tested system and wind load evalu ation satisfies the foll owin g co nditions:
I. The roof system is tes ted in accordance with AISI S906. Th e wind load is calcu laled using ASCfJSEI 7 for components and cladding, Method I (Simplified Proced ure) or Method 2 (Analytical Procedure).
3.
Th e arca of the roof bei ng evalu.alcci is in Zone 2 (edge zone) or ZOll e 3 (corn er zone), as defined in ASCE/SEI 7. i.e. Ihe 0.67 faclor does nOl appl y 10 Ih e field of Ihe roof (Zone I).
4.
The base metal thickness of the standing seam roof panel is greater than or eq ual to 0.60 mIll and less than or equal to 0.80 mill.
5.
For trapezo idal profile standin g seam roof panels, the dis tance between sidelaps is no greater than 600 ITIm.
6.
For vertical rib pro file sta nding scam f(Jof panels, the di stance betw een sideJ aps is no greate r tha n 450 Illlll . Th e observ ed failure mode of the test ed svstem is o rH~
of Ihe foll owing:
.
(i) The standing scam roof clip mechanically fai!.s
by sepa rat ing from {ile panel side lap· (ii)Thc st and ing sca m roof clip mechanically fails by the sliding lab separating from Ihe stationary basco
Groove . But(
..
Arc
~ ..
Weld
Sheel 10
sheet
P() ~;i ti on
Covered
.
Weldin ·Position ~quare
Con~~· .
C.3.6.3 Strength of Standing Scam Roof Panel Systems
2.
Oil
posi(ions as li sted in Table C.3.1 .
f.
7.
connected p
it.
F H
l'ilje'
WOld, . 'Up '
F
orT F
1-1
11
Fla{e
. Bevel
·drOOve F 11
Flare'
Weld F
II
·
V
V
V
.
-
OH
0 11
OH
Shcctto Support
·
F
F
F 11
F
.
·
11
ing
·
V
V
·
011
0 11
-
· ·
.
.
-
( I _ 031. Ii _ - hOfi lOnI.ll. V -_ \erll\;al. 011 _ O'Ct head)
v'''··
Groove
0 1-1
Member
V
AA ~~.~: Weld
.
C.3 .8 Bolted Connections In add ition to the design criteria gi ven in Section C3 .8 of thi s Specification, the following design requirements shall also be followed for bolted connecti ons used for coJdform ed steel structu ral members in which the thi ck ness of the thinnest connected part is less than 4.76 mm. Bolted connections in whi ch the thickness of the thinnest con nected parr is equal to or greater than 4.76 nlln shall be in acco rdance wilh ANS I IA ISC·360.
The holes for bolts shal! not exceed the sizes specified in Table C.3-2, except that larger hol es arc pcrmitted to be. used in colullln base details or st ructu ral systems connected to concrete walls. Standard holcs shall be lIsed ill bolted connections, except that oversized and slotted holes shal1 be permitted to be used as approved by the designer. The length of sloued hol es shall be nor mal to the direction of the shear lond. Washers or backup plates 511<111 be installed over oversized or slotted holes in an outer ply unless suitabl e performan ce is demonstrat ed by tests in accordance with Secti on 556. In the situati on where the holes occurs within the lap of lapped an d nested lee members, the above requirements regardin g the direction of the slot and the usc of was hers shall be
Associa tion o f Structural Engineers of the Philippines
permittcd not to apply, subject to the following limits: I.
12.7111111 diamctcr boll.,> only,
2.
Maximulll slot size is 14.3 mm x 22.2 vertically,
3
Maximum oversize hole is 16 mm diametcr,
4.
Minimum member thickness is 1.52
5.
Maximum mcmbcr yield :.;tress 410 MPa,
6.
Minimum lap length measured from center of frame to end of lap is 1.5 times the member depth,
Illlll
mll1
slotted
nominal,
Table C3-2
Nominal Bolt Diameter, d
< 12.7
MO.8
d+I.6
212.7
MI.6
d+3.2
(d+0.8) by (d+6.4)
(d+0.8) by (2';) eI)
(d+1.6) by (d+6.4)
(MI.6) by (2';)d)
C.3.S.1 Shear, Spacing and Edge Distance The nominal shear strength, PII , of the connected part as affected by spacing and edge distance in the direction of applied force shall be calculated in accordance with Eq.C36, The corresponding safety factor and the resistance factor provided in this section shall be used to determinc the available strength in accordance with the applicable method in Section 551.4 or 551.5.
(F.q. C3-6) When I'~I F" 2 1.08
Q
(b)
For oversized and slotted hole:.;, the distance between edges of two adjacent holes and the distance measured from the edge of the hole to the end or other boundary of the connecting member in the line of stress shall not be less than the value of e-(dhl2), in which e is the required distance used in Eq. C3-G, and dh is the diameter of a standard hole defined in Table C.3-2, In 110 case shall the clear distance between edges of two adjacent holes be less than 2d and the distance between the edge of the hole and the end of the member be less than d.
C3.8,2 Rupture in Net Section (Shear Lag)
mOl
(a)
In addition, the minimum distance between centers or bolt holes shall provide sufficient clearance I'DI' bol! heads, nuts, washers and the wrench but shall not be less than 3 times the nominal bolt diameter, d. also, the distance from the center of any standard hole to the end or other boundary of the connecting member shall not be less than I Y2 d.
= 2.00
(ASD)
(ASD)
(a)
For flat sheet connections not having staggered hole patterns
(Eq. C3-7) (J)
When washers arc provided under both the bolt head and the nut
For single bolt, or a single row of bolts perpendicular to the force
(Eq. C3-8)
¢ = 0.70 (LRPD)
When Pu / Fsy , 1.08
n = 2.22
The nomina! tensile strength of a bolted member shall be determined in accordance with Section 553. For rupture in the effective net section of the connected part, the nominal tensile strength, PI! shall be determined in accordance with this section. Unless othcrwise spccified, tbe corresponding safety factor and the resistance factor provided in this section shall be used to determine the available strengths in accordance with the applicable method in Section 551.4 or 551.5.
For multiple bollS in the line parallel to the force
¢ = 0.60 (LRFD)
where
f~
= FII
(Eq. C3-9)
For double shear: :::: Nominal strength per boll Distance measured in line of force from center of a standard hole to nearest edge of a adjacent hole or to end of connected part. :::: Thickness of thinnest connected part :::: Tensile strength of connected part as specified in Section 551.2.1,551.2.2 or 55 1.2.3. :::: Yield stress of connected part as specified in Section 551.2.1,551.2.2 or 55 1.2.3.
Q
= 2.00
(ASD)
l' = 0.65 (LRFD)
(ASD)
1 = (J.55 (LRFD)
:.0:
F,I)
For single shear:
n = 2.22
(2) When either washers are not provided undcr the bolt head and the nut, or only one washer is provided under
either the bolt head or the nul
th
National Structural Code of tile Philippines 6 EcJition Volurnc~l
CHAI'TE:n
S':Wif
~i
. Steel
all{j
Metals
For single bolt . or
F = (2.5,-d/,·)<' 1"1/ -< /' f
•
(Eq. C 3- 11)
2_22 (ASD)
::::: Nominal Tensile stress in Oat sheet = Nominal bolt diam eter = Shee t wid th di vided by num be r of bolt holes in cross secti on being analyzed (w hen evaluati ng !',) ::::: Tcnsile strength of cOll ncct ed part as spccified in Secti on 55 1.2.1, 551.2.2 Or 551.2. 3.
I~
l~,
= Dist;!lH;e from shear plane to ce ntroid of the
x
cross = Lengt h of cO llllec tion C.3 .H.3 Shear ~lIId Tension in HoU~
= Net Area of connected,pan
d
(b) Fo r flat sheet con nectio ns hnving staggered ho le patic lll s
The nominal bolt strength, PII , resu lti ng from shear. {cnsi(w or of combination of shear and tension shall be calc ulated ill accordan ce wi th th is secti on. The correspondi ng safety factor and the res istance factor prov ided in Table C.3-3 shall be used to determ ine the available strengths in accordance with Ihe appl ica ble mcthod in Section 551..4 or 55 1.5. (Eq.C. 3-17)
whe re
(Eq. C3- 12) Q = 2.22 (ASD)
¢ = 0.65
= determined in accordance wit h Eqs. E3.2-2 to E3.2-5. = 0.90 [A, -- nbdhl + (.[s'214g) t] Eq. C.3- 13) = Gross area of mem ber = Lo ngitudi nal center-Io-cen ter spac ing of any tw o consecutive holes = Transverse ceni er-Io-eelller spac ing between fastener gauge lines :::: Num be r of bolt holes ill the cross secti on being an alyzed = Diameter of a slandard hole
A"
A, g
nb db
::;: Gross cross-sectional arca of bolt :::: Nominal strength ksi (M Pa) is determined in accordance with (a) or (b) as foll ows:
(LI~FD )
where
F,
(E(I. C.3- 16) blli IJ ~ 0.5.
where
¢ = 0.65 (LRFD)
where
A"
U = 1.0 -- 0.3(, xli. dl.9
(Eq. C3- 10)
/I
For multiple boils in Ihe linc parall el 10 the force
Q =
(2) For channc l mcmbcrs having two or more bolts in the line or r{)n. · l~
(a) When bolts are subjected to shear onl y or tcnsio n only F" shall be given by Fm. or Fill in Table C.3 -3. Co rrespo nding safety and resistance factor. Q and ¢, shall be accordance with Tablc C. 3-3. The pullover stre ngth of the connected sheet at the bolt head, nut or washer shall bc considered where boll te nsion is involved. See Section 555.6. (b) When b olts arc su bjected to a co mbination of shear and tension, F" . isgi vcn by F'II I ill Eq .C.3-1 8 or C.3- 19 as fo llows
See Sec tion C.3.8. 1 for the defini tion of I.
For ASD
(c) For other than n at sheet
F'fI1 ::;: 1.3 F'll - QF",/v:S; 1'~11
Fil"
(Eg. C.3- 14) Q
= 2_22
(AS D)
~
= 0.65 (LRFD)
(Eq. CJ- J 8)
For LRFD
w here AI' /:
= A"U, effec tive net area wi th U defin ed as fol lows : :::: I .U fo r members when lhe load is lransm iHf..'d di rectl y to all of the cross-secti ona l cleme nts. Otherwise, the reduction coefficient U is determined as foll ows:
( I ) For A ngl e member:-; having two or more bolt s in the
li ne o f force
u = 1.0 -
1.20 xlL < 119 (Eq. C.3- 15) hut U ~ 004
Association of Slnlclum! Engineers of the Philippines
(Ell. C.3- i 0) ¢F"..
whc re F'III
I'~' I
":". F" s)
¢
Nomi nal tcns ile stress modified 10 include 111\.~ effc(;ls of required shear stress, MPa = Nominal tensile stress from Table (:,1-1 ;:: Nominal shear stress from THble C.3 -3 :::: Required :o;hear stress, MPa ;:: Safety factor for shear from Table C.1-3 :::: Resistallce factor for shear from Table C.3-3 ;::
...,~.
In addition, the required shear stress,!.., shall not cx(;eed the allowable shear stress, f~", I 12 (ASD) or (he design shear stress, $ F",. (LRFIl), of the fasteoer. Table C.3 ·3 Nominal Tensile and Shear
. for Bolts
Safely
Factqr
Boll'
Fa~tor
n
q)
Mpa
' Mp"
:!.15
279
165
2.25
.110
IR6
621
372
621
496
696
407
0 .75
6.4 mm S d < ! 2.7 mm, when threads .lre not excluded frol1l shea r :Illes A449 Bolts 6.4 111m Sd < 12.7 111m, when threads
Slre,i Pi.
streSs Pnl
2.00
\I,'hell threads
696
2.4
0.65
621
558
,\2-1
558
,1%
776
465
776
621
A490 Bolts when threads arc not excluded from
shea r In Table C.3-3, the shear st rength shall apply LO bolls in holes a$ limited by Table C.3-2. Washers or back-up plates shall be installed over long-s Jollcd holes and the c
C.3.S.3.1a Connection Shear Limited by End [)i!;lmlcc
The nominal shear strength per screw, 1"11 shall not exceed that calcu l
National Structural Code of Ole Philippines 6
th
Edition Volume 1
~)
30G
CHJ\PT [H
~j .
Steel and tv-tetal:;
(liq.Cl·20) {) - ).00 (AS D)
mct hod in Sl'l.:liol1 551.4 or 551 5. (13'1. C.3·22)
¢ = 0.50 (I .R !'D)
when.'.
('
(Eq. CJ·231
= Thickness of pari in which end (jisllUlce is Illcasurcd = Distance measured in lille of for!';c from center of 11 standard hole to nearest end of con nected pan. = Tensile strcngth of pall in '::ilich end distan<.:c is
For bolted t:ollncctiolls
n
= 2.22 (ASD)
n = 2.50
(AS D)
At bcamwcnd connec tions, where one or more flanges arc coped and failure might occur along a plane through the fasteners, the nomin al shear strcngth, Vn • shall be calculated in accordance with Eq, C.3 21. The safcIY factor and Ihe resistance factor provided in this section shall be used to determine the available strengths in accordance with thc applicable method in Sect ion 551.4 or 551.5.
Gross area subject 10 shear Net arca subject to shear Net area subj ect 10 tension
w
(Eq.C.3·21) Q
= 2.00
(ASD)
¢ = 0.75 (LRFD)
where A"." II"., "
d" Fu
t = 0.60 (/'RI'O)
wllcrc
C.3.9.1 Shear Rupture
0.65 (LRI'D )
For welded connections
measured.
C.3.9 Rupture
t=
= (h",<, - nd/j)t = Coped flat web depth = Number of holes in cri ti cal plane = Hole diam eter = Tensile strc ngth of connected pMt as specificd in Section 551.2. 1 or 551.2.2 = Thickness of coped web
C.3.9.2 Tension Rupture The av'lilable tensile strength along a path in the affected elements of connected members shall be determined by Section 555.2.7 or 555.3.2 for welded or boited connections, respectiv ely. C.3.9.3 llIock Shear Uuplure When the thickness of the thinncst connected part is less
than 4.76111111, the block shear rupturc nominal strength, N", sha ll be determined in accordance with thi s sec tion. Connections in whi ch the thi ckness of Ihe thinnest connected part is equal to or greater than 4.76 mm shall be in accordance with ANSI/ AIS C-360. The nominal block shear rupture strength, R , shall be " determined as the lesser of Eqs. C.3·22 and C.3-23. The corresponding safety factor and the resistance factor provided in thi s section shall bc used to determine the avai lable strengths in accordance with the applicable
Association of Structural Engineers of the Philippines
NSCP C101·10
Chapter 6
WOOD NATIONAL STRUCTURAL CODE OF THE PHILIPPINES VOLUME I BUILDINGS, TOWERS AND OTHER VERTICAL STRUCTURES SIXTH EDITION
Association of Structural Engineers of the Philippines Suite 713, Future Point Plaza Condominium I 112 Panay Avenue, Quezon City, Philippines lion Tel. No: (+632) 410·0483 Fax No.: (+632) 411·8606 Email: .ll5.£l)on!i!l£[email protected]!.com Website: http://www.aseponline.org
111
National Structural Code of tile Philippines 6 Edition Volume 1
CHM)T F n G
VI/ OO(j
() · 1
Table of Contents CHAPTER 6 . WOOf) .............................................................................................................................................................. 4 SECTION 60 1 - GENERA L ..................................................................................................................................................... 4
601.1 Scope .. 60 1.2 Design Method ........ ..... ..... ..... ... ..
...... 4
. ..... 4
SECTl () N 602 - DEFI NITI ON S ..................................................................... .'................................................. ,....................... 4
602.1 Definitions ..
........ 4
SECTION 603 - MINIMUM QUA LITY ................................................................................................................................. 5
I I
603.1 Quality and Idcnlifical;oll ... ... ...... .. ....... ...... . 603.2 Minimum Capacity or Grade ....... ........................... . 603.3 Timber COllllectors and Fasteners .... 603.4 Fabrication, Installation and Manufacture ,., .
..5 ... 5 .... 5 . .... 6
SECTION 604 - DESIGN AND CONSTIWCTION REQUIREMENTS ............................................................................. 7
604.1 General.
...7
Part 1 - nequircmcnts AppJie3ulc (0 All Design
Methods ....................... " ....................................................... "" ........ 7
SECTION 605 - DECA Y AND TERMITE PROTECTION .................................................................. ,.............................. 7 .. .. . 7 .7 .... 7
605. 1 Preparation of Building Site .... 605.2 Wood Suppon Embedded in Grou nd .. 605.3 Under-Floor Clearance .. .. 605.4 Plales, Sills and Sleepers ... 605.5 Columns and PosIS..... .......... . 605.6 Girders Entering Masonry or Concrete Wall s
.... 8 .8 ..8
.... 8
605.7 Under-Floor Ventilation .. .
... 8 ....... 8
605. 8 Wood <1nd Earlh Separation ............................................... .
605.9 Wood Supporting Roofs and Floo rs .. 605.10 Moisture Comcnl of Trcatcd Wood .. 605 .11 Retaining Walls ...... . 605.12 Weather Exposure ... ....... .... .... 605.13 WalerSplash .. .. ........... .... .......... .... .. ..
.. ....
' 8 ....... . 8 ...8. .. ... 9
SECTION 606 -WOOD SUPPORTING MASONRY OR CONCRETE .............. ,................ ,...................... ,.. ,.................. , 9
..... ............. 9 .... 9
606.1 Dead Load ... 606.2 Hori zontal Force ..
SECTION 607 - WALL FRAMING ................................................................................................... ,......... ,......................... : 9 SECTION 608 - FLOOR FRAMING ............................... ,................ ,.................................................. ,....................... ,........ 10 SECTION 609 - EXTERIOn WALL COVERINGS .......................................................... ,........................................ :........ 12
.. 12 ..... 12 ......... 12 .. ... 12 .. 12 .. ........... 12 ... I3
609.1 Gen eral. 609.2 Sidiug ......... .......... ... .. 609.3 Pl ywood .. . 609.4 Shingles or Shakes .. 609 .5 Parlicleboard ..... . 609.6 Hardboard .. .... . ................ .. . 609.7 Nailing..... . ..... .. ........................ ...... ........... .. . .
SECTI () N 610 - INTER! () R P A NELIN G .. ,.... ,.... ,............... ,..... ,.... :.......................... ,....................................................... ,.. 13
National S tructural Code o f U1e Philippines 6
th
Ed ition Volume 1
6·2
CHAPlLfi 6 . Wood
SECTION 61 I . SHEATHING ............................................................................................................................................... 14 6 J I" I Structural Floor Sheathing .. 61 J.2 Structural Roof Sheathing ..
.. ................. 14 ························ ...... 14
SECTION 612 - MECHANICALLY·LAMINATED FLOORS AND DECKS ................................................................. 14 SECTION 613 . POST-BEAM CONNECTIONS ................................................................................................................ 14 SECTION 614· WOOD SHEAR WALLS AND DIAI'HRAGMS .............................................. ·....................................... 15 614.1 General ..
.. .. ··· ............. 1,')
614.2 Wood Members Resisting Horizontal Forces Contributed by Mas(wry and Concrctc ..................................... Ie 614.3 Wood Diaphragms.. ............................. 16 614.4 Particleboard Diaphragms .. ............................. 17 614.5 Wood Shear Walls and Diaphragms in Seismic Zone 4 .. . ...... ........ . ..................... II 614.6 Fiberboard Sheathing Diaphragms .. . .................................................. 18
SECTION 615 . STRESSES ................................................................................................................................................... 18 615.1 General ..
615. J.I Repetitive Member System .. 615.2 Stresses in Piles Used as Structural Members .. 6iS.3 Adjustment of Stresses ........................................................................... . SECTION 616· HORIZONTAL MEMBER 6i6.1 616.2 616.3 6 J 6.4
.. ..................... 18 .. ................. I g . ............................................ IS ........... .... 19
DESIGN ................................................................................................... 22
Beam Span ..
................. 2? .......................... 2; ............................. 27 ................ 22 . ..................................... 2!
Flexure .. Horizontal Shear.
Horizontal Shear in Notched Beams .. 6 J 6.5 Design of Joints in Shear .. 616.6 Compression Perpendicular to Grain .. 616.7 Lateral Support..
.................
. .............. ..
616.8 Lateral SUPPO!1 of Arches, Compression
Chords of Trusses and Studs ..
. ............ 23
.......... 2:l ............. 24
SECTION 617· COLUMN DESIGN ..................................................................................................................................... 24 617.1 Column Classifications.. 617.2 Limitation on lid Ratio.. 617.3 Simple Solid-Columll Design. 617.4 'rapered Colunlns ............ ........................ ........................................................................
SECTION 618· FLEXURAL AND AXIAL
. ................... 24 . .............. 24 ... ,............................ 24 .... 25
LOADING COMBlNED ........................................................................... 25
618.1 Flexure and Axial Tension ............................... . ......... 26 618.2 Flexure and Axial Compression ............................................................................................................ . . ... 26 . ... 2() 618.3 Spaced Columns ........................................................................................... . 6 J 8.4 Truss Compression Chords.. . ................... .. ....................... 26 ..... 21 618.5 Compression at Angle to Grain ............................................................ . SECTION 619 . TIMBER CONNECTORS AND FASTENERS ........................................................................................ 2'7 619.1 619.2 619.3 619.4
Gelleral ................... .......................... ...................................................... Bolts... ............................... Nails und Spikes..
Joist Hangers and Framing Anchors.. 619.5 Miscellaneous Fasteners.
....................... .............. ............................................ ..................
619.5.2 Spike Grids.
..... 2"1 ..27 .. ...... 27
.. .... 28 .. .. 28 ........ 28
SECTION 620 - CONVENTIONAL LlGHT·FRAME CONSTRUCTION DESIGN PROVISIONS ............................ 28 620.1 General ............................................................................................................. .. 620.2 Design of Portions........... ............................ ............... .
620J Additional
Requirements for Conventional Construction in High-wind Areas. Association of Structural Engineers of the Philippines
.... 29 29 ...29
G "·,
620.4 Addit ional R(:qlliremcllI s for Conven ti ona l CU llslnKlioll ill Se ismic Zone 2 620.5 Additional Requirements for COllve ntional Consllw:tioll in Seismic ZO IW 4 " . 620.6 G irders 620.7 Floor Jois ts .. 620.8 Subnoorin g .. 620.9 Part icle boa rd Undcrlaymcnt. 620.10 Wall Fram ing" """"""""" """" "" """""."
.... 2t)
,,"" 29 .JO
.30 .... 31 ..31 "".3 1
SECTION 621 - METAL PLATE CONNECTED WOOD TRUSS DESIGN.".""""""".""".""""" .. "".""""".".".".".,,34
62 J. J Design and Fabrication..
.. ... ........ ...... ""
621.2 Performance ........ .................................... ... ,' 621.3 Jn ~ PJant Inspection .... . 621.4 M arkin g
.. 34 . """" " 34 ." 34 " 34
SECTION 622 - USE OF MACHINE GRADED LUMBER (MGL)" ... ""." ................................................ " .................... 35 622. 1 General "." .... "" .. " ................. . "." .. "
622.2 Design Properties for Machine Graded Lumber ..... 6223 Des ign Us in g Machine Graded Lumber ........................ .. . 622.4 Prese rvat ive Treatment ............................................ .
622.5 Mois ture Co nt em . 622.6 Markings """""""",,,, ",,""",,",, " """" .,, "" """. """"" " " ."
National Structural Code of th e Philippines 6'" Edition Volume 1
........ "" .. " ..... " .. ,," 35 ...,," 35 . . ." .. 35 ... 35 "" 35 " 3S
CHAPTER 6 WOOD
FIBERBOAHn is a fih rous-fell ed, homogeneous P'U1ci made from li gnocellu los ic libel'S (usua ll y wood or SUgiU <: alH,~ bagasse) lIlld havin g 11 de llsity o f kss than 497 kg/m.l but morc than 160 kg/ nr',
SECTION 601 GENERAL 601.1 Scope T he qu al ity and design of wood membe rs an d their
fa stenings shall co nform
\0
the pro visions of Ihis chapter.
601.2 Desigll Method Des ig n shall be based
Oil
one o f the foll owing methods:
601.2.1 Allowable Stress Dcsigll (ASD). Design usi ng alhlWit b!c stress design methods shall res ist th e different load cO lllbinations in ac(';o rd ancc wi th th e
app licabJe rcql]irCIllCllis of Section 604.
FOREST PRODUCTS RESEAR C H AND DEVELOP_ MENT INSTITUTE (FPIWI) is the Department 01' Science and Tcdlll ology's (DOST) rcsearch and development arlll on forcs t prod ucts utili zation. It !" mandated 10 conduct basic an d ap pli ed research to help the woodHusing ind ustries di sscmirwl c in ronnati on ;:1l 1d technologies on forest produ cls \0 end users, GLUED BUILT-UP MEMBERS a rc st ruc tural cle mc",s. the sections of which arc composed of built -up lumbe r, wood structural pan els or wood structura l panels in
co mbination wi th lumber, all pa rts bonded IOgcther Wi lh adhesive. GRADE (Lumber) , th e cJass ili cat io ll or lumber in regard to strength and utility in accord ance with th e grading rules of an approved lumber gnloin g agc l1 CY.
(0) .2.2 Conventional Light-Frame Construction.
The design and construction of conventional li ght -fram e wood slnJ clUrc.s shall be in accordance with th e applicabl e rcquircmcllIs of Section 604 and the NSCP Volume 3 on '-lo usi ng.
MACHINE GRADED LUMBER (MGL) is a IUlllbu evalu atcd by a mach ine usi ng <1 n on~dc$t ruc ti ve lesl
SECTION 602 DEFINITIONS
'"11(,,"11
602. 1 Definitions
The following tefm s used in thi s chapter shall hnve the me anin gs indi cated in this section: BLOCKED DIAPHRAGM is a diaphragm ill whi ch all "ht.::;ltll i ng edges not occun'ing on framin g mem be rs are S LlPI' { H ' (~'d on and connected to blocking. BR,\ C J::Jl WALL LINE is a scrics of braced Wil li pa ll cls ill a si ngic story that meets the requiremellts of Secti on 620. 11 ),,\. CO NVENTIONAL LIGHT-FRAME CO NSTR UCTION is a type o r COll s tlllCt ioJl in whi ch the pr imm)' stJ'UclUral clement s nrc formed by a system of re petiti ve wo()(I· rr;l ming members.
I)lAl'l-IRAGM is
HARDBOARD is a fib rotl s· (cit cd , homogeneolls panel made from lignocellul osic fi bers co nsolidated under hc,i\ and pressure in a h OI press 10 a de nsit y not less than Ij\ i ) kg/Ill'.
il
hori z.ontal or nearl y horizontal sys tem
actin g to tra nsmit late ral forces to the ve rti cal resisti ng C k~ Jll e nI S. Wh en the term "diaphragm is used, it incl udes hori l,OIHal bracing systcms.
MOISTURE CONTENT (M e) is the o f moist ure in wood, usuall y measu red as the p:!rcc nt age of w;lt er to tli! oven dry wei ght of the wood .
NOMINAL SIZE (Lumber) refers to th e co mmercial si?-i.: designation of width and depth , in standard sawn lUlllh~; grades; somewhat larger th an the standard nct size \i1 dressed lurnber. NORMAL LOADING . a dcs igll load that stresse': mcmber or fastening to the full all owable stress tabula{c, ' thi s chapter. This loadin g may be appli ed for appro xim;" J() years, eit her continuously o r cum ulativc/ y, and 90 pe rcc nt of th is load may be applied fo r the remainder of tl),; lire of' th e mcmber or fasteni ng. I)ARTJCLEBOARD is a malltlfactured pa nel pn"in, co nsistin g o f pal1icies of wood or combinations of ':,'0.,, ; particles and wood fi bers bonded togeth er wi th sYl,dlctit: resins or other suitable bondin g sys tem by a h llld ing process, in accordance with app roved nati onally r(',cognized standard.
Associati on of Structu ra l Engineers of the Philippine s
PLYWOOD is it pane! of lalllinated veneers conforming [0 Philippine Nation,ll Standards (PNS 196) "Plywood Speci II cations". nOTATION is (he (orsiollal about a vertical axis.
III 0 V,'""," (
01 a diaphraglll
STRUCTURAL GLUED-LAMINATED TIMBER rs any member comprising an assembly of laminations of· lumbcr in which the grain of al! lalllinatioJl.~ 1.'-; approximately parallel longitudinally, in which the laminations arc bonded with adhesi ves.
SUBDIAPHRAGM is a portion of a larger wood diaphragm designed to anchor and transfer local forces to primary diaphragm struts and the main diaphragm. TREATED \\I00n is wood trc,\(cd with an approved
preservative under treating and quality control procedures. WOOD OF NATURAL RESISTANCE TO DECA Y OR TERMITES is the heartwood of the species set forLh below. Corner sapwood is permiLted on 5 percellt of the pieces provided 90 perccll! or more of the widLh of each side 011 which it occurs is hcartwood. Recognized species arc
Decay resistant: Narra, Kamagong, Dao, TangiJe. Termite resistant: Narra, Kamagong. WOOD STRlJCTlJRAL PANEL is a strtlcttlral panel product composed primarily of wood and mecting the UBC Standard 23··2 and 23-3 or equivalent requircments of Philippine National Standards (PNS). Wood structural panels include all-veneer plywood, composite pancls containing a combination of veneer and wood-based material, and mat-formed panel such as oriented stranded board and waferboard.
SECTION 603 MINIMUM QUALITY 603. J Quality and Identificatioll All illlllbcr, wood structural panels, particleboard, Limber. end-jointed lumber, Ilberboard shemhing (when used structurally), hardboard siding (when used sLructurally), piles and poles regulated by this chapter shal! conform to the applicable standards or grading rules specified in this code and shall be so identified by the grade mark or a certitlcate of inspection issued by an approved agency. 603.2 Minimum CHpacity or Grade Minimulll capacity of structural framing members may be established by performance tests. When the tests Me noL made, capacity shall be based on allowable stresses and design criteria specified in Lhis codc. SLuds, joists, rafters, foundation plates or sills, planking 50 mill or more in depth, beams, stringcrs, posts, structural sheathing and similar load-bearing mcmbers shall be of" at Jc.ast the minimum grades set forth in Table Nos. 6.1 or Table 6.2 or Table 6.35. Approved end-jointed lumber Illay be used interchangeably with solid~sawn members or the same species and grade. Such usc sha!l include, but not be limited to, light-framing joists, planks and decking. Wood structural panels shall be of grades specitled in accordance with Philippine National Standards (PNS).
603.3 Timber Connectors and Fasteners Safe loads and design practices for types of connectors and fasteners 110t mentioned or fully covered ill Section 6 I y, lllay bc determined in a manncr approved by the building official. The number and size of nails connecting wood mcmbers sha!l not be less than that set forth in Tahles 6.:1 and 6.4. Other connections shall be fastened to provide equivalent strengLh. End and edge distances ilnd nail penetrations shall be in accordance with the applicable provisions of Sectio]) 619. Fasteners for prcssure-preservative treated ,lJ1d f"ircretardant treated wood shall be of hot-dipped I.inc coated galvanized, stainless stcel, silicon bronte or copper. Fasteners required to be corrosion resistant shall bc either zinc-coated fasteners, aluminu1Tl alloy wire. LIsteners or stainless sleel fasteners
6· ()
C H!\P 1[r~ G . VI/oud
COII IlL'ctions depending on joist h:mgc rs or fra ming JIIH.:hors. fi es, mid other mechanical fastenings nol otherwise covered lJla y be used where 'Ipprovcd by th e Building Offici'l!. 603.4 Fabrication, Installation and Manufacture Fabri<.:ation, installation, and manufllcture of wood clements shall be in accordance with the following guideli nes: 60 . ~ . ,·i ,J
General
Prepa rmion, fabrication and installation of wood members rind th eir fastenings shall conform to accepted engineering practices and 10 the requirements of this code. All members shall be framed , anchored, tied and bmced to deve lop Ihe strength and rigidity necessary for the purposes for which th ey arc used.
603.4.7 Shrinkage Conside r'l li on shall be given ill tht, d e"ig n 10 Ihl..' pm:~ j hl t"_ elTect uf cros s-g rain dimcnsilHlill l: han!,~l:s l'OIl.'.;(] Cl':>, j ve rtically which ma y occur in IUIll lwl' r"bric
603.4 .2 Timber Connectors :md Fasteners. T he install ation of limber connectors and fasteners s hall be
illllccordllncc with the provisions set forth ill ScclioJl 6 19. 603.4.3 Mct:ll-Plate-Collnected Wood Trusses Metal -plate-connected wood trusses shall conform 10 the provisions of Section 618. Each manufacturel' of trusses Ilsing metal plate connectors shall retain ,1I} approved agellcy having no financial interest in the plant being inspected to make nonscheduled inspecti ons of tru ss fabrication, delivery, and operations. The inspection shall cover all phases of truss operation, including lumber storage, handlin g. cutti ng, fixtures, presses or rollers. fabrication, bundling and banding. handling and deli very. 603,4.4 S tru ctura l Glued-Laminated Timber
The manufacture mul fabrication of stru ctural glucdla!llinatcd tiln bcr shall be under the su pervis ion of qua lified personnel. 603.4.5 Dried Fire-Retardant-Treated Wood Fire-retardant treated wood shall have been dried. following treatment, up to maximum moisture content (Me) as follow s: J 9% - for so lid sawn lumber up to 501ll1ll thick 15% ~ for plywood
603.4.6 Size of Structul'al Membel's Sizes of lum bcr referred 10 in {his code are nominal sizes. Compulati oJl$ to determinc (he required sizes of me.mbers sha ll be based Oil the net dimensiolls (acl ual Si7.C) ilnd not the nomina l sizes. The- rough size lumber shall not be less than the nomina l size .and the red ucti on in face di mensions of dressed lumber shall not be morc than 6 mm of the nominal sizc.
Association of Structural Engineers of the Philippines
CHA pnl~G ·
SECTION 604 DESIGN AND CONSTRUCTION REQUIREMENTS
PAjlT I . . ; . '.
. ' .
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Th e foll owi ng desig n requirements apply.
SE(;TION',@S
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6()4.1.f All
PROTECfldN'"r,.<. . •·;·i •.·.(
604.1 G I.'m'ral
slnH.: turcs
shall
be
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DECAY. AN6;TERMIT-E·
designed
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REQUIREMENTS'APPJ;JCABI.,E TO ALL DESIGNM'ETnODS . · ' . ' ' ' ·'· :'·r'.''.f;'''' -'
wood
Wood
and
constructed in m:conlanct: ,. .·ith the requirements of Section ()(J J up to St!ction 611. 604.1.2 Wind and c
wond sl ruclU res shall be designed and construc ted in accordance w ilh the requi rements of Section 6 14.
User Note: Ahe rn ati vely, lateral load-resisting' sys tems for single family dwellings may be propo!1ioncd accordiJ1g to the provisions of NSCP Volume 3 on Housing.
604.1.3 T he design and construction of wood structures ll si ng all owable st ress design (AS!)) methods shall be in accordance with Section 615 and Section 6 J 8. 604.1.4 The design and construction of" conventional light · fraille wood structures shall be in accordallce with Sectioll 620. 604.1.5 The des ign and installation or limber conllectOrs and fasteners sh;lI l he in 'Kcordallcc with Scclion6 19.
604.1.6 Mcta l· pblc·nHlnected wood tru sses shilll conform to thc provisions of Sec tio1l 62!.
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605.1 Preparation of Building Site All Slumps and roots shall be removed from the so il to a depth o f at least 300 mm below the surface of th e grou nd in the area to be occupied by the bui lding. All wood forms whi ch have been used in placing concrete. if within the ground or between found.llion sills and the ground, shall be removed before a building is occ upi ed or used for any purpose. Before completion, loose or casual wood shall be removed from direct conwct with the ground under the building.
605.2 Wood Support Embedded ill Ground Wood embedded in the ground or in di rect contact with the earth and llsed for the support of permanent structures shall be treated wood unles s continuously sub merged in fresh water. Round or rectan gular posts, poles tln d sawn timber coluillns supporting permanent stru ctures which arc embedded in concrete or masonry in direct cont act wit h the earth or embedded in concrete or maso nry exposed to the wea ther shall be treated wood. The wood sha ll be treated for ground contact. 605.3 Undcr~Floor Clearance When wood joists or the bottom of wood st ru ctu ral 1100rs without joists arc located closer than 450 mill or wood g irders are located closer th an 300 mm to exposed grou nd in crawl spaces or unexcavated areas located within the periphery of the building foundati on. the floor assembly including posts, girders, joi sts and subfloOf, shall be approved wood of natural resistance to decay as listed in Section 605.4 or treated wood.
When th e above under-rIoor clearances arc required, the under"l1 oor area shall be accessibl e. Accessible und er~noor arC,I$ shall be provided with a min imum 450 mill by 600 mill openin g unobslructed by pipes, ducts and similar co nstrucli on. All under-floor access open ings shall be effec tivel y screened or covered. Pipes, ducts and other co nstructi on shall not interfere with the accessibil ity to or wit hin under-floor areas.
ll
National Structural Code of tile Pililippines 6 \ Edition Volum e 1
6·[)
CHAPll:f~
G . \Nood
605.4 PIHtCS, Sills and Sleepers All fOllnd;l1ioll plates or sills and sleepers OJl a concrete or masonry slab, wh ich is ill direct co nt ac t with earth, and sills thai rcs t 0 11 concrete or masonry foundations, shall be treated wood, all marked or branded by an approved agency. Foundation wood marked or branded by an approved agcncy may bc uscd for sills in localities subject to moderate hazard, where termite damage is nol frequent and when specifically approved by the building oiiwial. In localit ics where ha zard of termite i s slight, any spccies or wood pcnnillcd by thi s chapter ma y be used for sills when specificall y appro ved by the building offi cial. 605.S COIUIIIIIS "lid Posts Columns and posts located on concrete or masonry floors or decks exposed 10 the weather or 10 water spla<;h or in basements and which supp
Individual co ncrete or masonry pi ers shall project at least
(llld located ncarer than 150 min (0 eHrth shal l be treated wood or wood of lI,tlllral n;!)istmlCc Iu dc(;,ty. Where loca ted on concrete slabs placed on coll'lh. wood slwll be tre ated wood or wood or natural resistance to dec
the air space is less th an 150 mill in width . Wherc Oas hing is used, provisi ons shall be made to permit circulation of the air in the air space. The wood frame shall be provided with an exterior wall covering conforming 10 the provisions of Section 609 . 605.9 \\food Supportillg Roofs Hnd Floors
Wood stnlctura l members su ppo rting concrete or masonry slabs which arc permeable 10 moisture and nrc exposed to the weather shall be approved wood of natural resistance to decay or treated wood unless separated from such noms or roofs by an impervious moisture balTic!'.
200 mm above exposed ground unl ess the supported
columns or posts arc treated wood or of approved wood wi th natural res istance to decay.
605.10 Moisture Content of Treated \\food
When wood whic h has bee n prcssurc-trcalCd with
water-
born prese rvat ive is used in enclosed locations where
605.6 Girders Entering Masonry or Concrele Walls Ends of wood girder entering masonry or co ncrete walls shall be provided with a 13 mm air space on tops, sides and ends unless approved woud or natural resistance (0 decay or treated wood is used.
drying in service ca nnot readil y occ ur, slich wood must have 11 moisture con lc.nt of 19 percellt or less before being cove red with insula ti on, intcrior wall finish 11001' coverin}" or other materials.
605.11 l{c(aining Walls 605.7 Under-Floor Venlilalion
Under-floor areas shall be ventilatcd by an approved mechanical mea ns or by openings in exterior foundation walls. Such ope nings shall havc a nct area of not less than 0.067 111 2 for each 10 rn 2 of under-floor arca. Openings shall be located as close to corners as practical and shall provide cross ventilation. The required area of such openings shall be approxim ately equally distributed along the length of at least two opposite sides. They shall be cove red with con·osioll-resistant wire mcsh with mesh openings of 6 I11Ill dimension. Where moist ure due [0 climatc and grou nd watcr conditions is not considered excessive, the building official may allow opclable louvers and ma y allow the required net area of vent openin g 10 be reduced to 10 percent of the above, provided th e under-floor ground surface area is covered with an approved vapor barrier. 605.8 Wood and Earth Separation
Protection of wood against deteriorati on as set fort h in the previous sections for speci fied applications is required. In addition, wood used in construction of permanent stIUctures
A ll wood llsed as permanent part s of retain ing or c rib walL shall be treated wood.
605.12 Weathcr' Exposurc Those pm1ions of glued- lam inated timbers that form l:j' ~ st ructural supports of Cl building or other stru cture and which are exposed to weather and not propcrly protected by a roof or cave ove rhangs of similar covering, shall be press ure -treate d wi th an approved preservati ve or \;(~ ma nuf:tctu red fro m wood of natunli resisl;mcc to decay.
All wood structural panels, whcn designed !O be exposed ill outdoor application, shall be or exterior type, exce pt ns provided in Section 605.2
In geogra phi cal areas where ex perience has demonstrated a speci fi c need , approved wood of natural resi stance to decay or trea ted wood shall be used for those stru cturfl!. co m.ponents of buildi'ngs or similar perm anent buiJdih ; ~ appurtenances whcn such members are exposed 10 til weather and are without adequate protection provided by ?
Association of Structural Engineers of the Philippines
CHAPH:J~
G · WOO(j
6·9
roof. C; IV(,\ overhang or other covering against moisture or wat er
sllch as girder.Ii, joists and decking; or vertical members such as posts, poles and columns; or both hori zo ntal and vertical mcmhcrs. 605.13 W'Hcr Splash Where wood-framc walls and partitions arc covered on the interior with plaster, tile or similar materials and are subject 10 water splash, the framing shall be protected with approved waterproofing . . ':W :: '
3.. I
, ,'
606.1 Dead Load Wood men1bers shal! not be lIsed to permancntly support dead :oad .9f.any masonry or concrete except in cases listed below or allowed by relevant sections of NSCP Volume 3 Oil HOllsing. Exceptions: 1.
Masonry or concrete lion-structural floor or roof surfacing !l0/ more than 100 mIT! thick may be supported by wood members.
2.
Any structure may rest upon wood piles cons/rucled itl accordance with the requirem etJIs of Chapfer 3 on "Excavations and FOllndations"
3.
Veneer of brick or concrete stOlle may be supported by approved (n!ated woodjoufldafions when tile maximum height of veneer does lIot exceed 9.0 m aboY(! the foundations. Such lIelleer used as all iflferior wall finish may also be supported on wood jIoors which are designed to support the additional load, and be designed to limit the deflection and shrinkage to 1/600 a/the span a/the supporting I1u!miJers.
4.
Wood may be Ilsed to suppor! glass block masonry having an installed weight of 98 kg/m2 or less. When glass block is supported 011 wood floors. fhe floors shall be designed to limit deflection alld shri"kage to 1/600 of the span of the supporting member,\· alUl the allowable stresses for the framing members shall be reduced in accordance with Section 615.3.4.
606.2 Horizontal Force Wood mcmbcrs shall not be used to resist horizontal forces contributed by masonry or concrete ' construction in buildings over one story in height except where allowed by provisions of Section 614.2 of this code.
National Structural Code of the Pililippines 6'" Edition Volume 1
6·10
C IM p ·! E n G WOO(t
SECTION 608 FLOOR FRAMING The framin g of exterior and interior wa lls shall be ill accordan ce with provisions specifi ed ill Section 620 unl ess a specific design is furnished. Wood studs walls and bearing partitions shall not support more than two noors and a roof unless .1Il anal ys is satisfactory to Ihe bui lding official shows th.1I shrink age of wood framing will not have adverse effect upon the st ructure nor any plumbing, electrical, mechani cal systems nor other equ ipment installed therein due 10 Ihe excessive shrinkage or differential movements caused by shrinkage. The analysis shall also show that the roof drainag~ system and the forcgoing systems or equipmcnt will not be adversely affec ted or, as an alternate, suc h systems shall be designed to accommodate the differential shrinkage or mo vements.
Wood.joist ed floors sh;lll be framed and co nstructed and anchored to supporti ng wood stud or masonry walls. Fire block and draft stops shall "Ie in accordance with thc follow ing provision: I.
In combustible const ru cti on, fi re bloc ks and draft regu lators shall be install ed to cu t off all concealed draft ope ni ngs (both venical and hori zontal) and sh all form an effective barrier between floors. between a top story and a roof or attic space, and shall subdivide attic spaces, concealed roof spaces and floor-ceiling
assemblies. Th e integrit y of all fire and draft SlOps shall
be maintained. 2.
Firc. bloc ks slwll locati ons:
he provided in the following
2. t In concealed spaces or stud walls alHl pa!1ilions, including furred spaces , at the ceiting and floor levels, and at 250 mm intervals along the Icngth the wall.
or
E'(ceptioll: Fire bloi'ks may be omitted at floor and ceiling levels when approved smoke-actual(~d fire dampers are installed at these levels.
2.2 At all interconnections betweet) cOllcealed ve rtical and horizontal spaces such as those that occur at soffits, drop ceilings, and covered ceilings.
2.3 In concealed spaces between stair stringers, at tbe top and botlom or the r Ull , and betwee n studs along and in line with the nm of the stai rs if the walls under the stai rs are unfinished .
In open ings around vents, pipes, du cts, chim neys, fire places. and similar openings which afford a passage for the fire at ceiling and floor levels, with noncombustible materials. 3.
Fire blocks shall consist of SO mm nominal lumber or one thi ckness of 18 mill plywood wi th joints backed by 18 mm plywood or one thi c kness of 19 111m Type 2-I\-;· particleboard. I·. . jrc stops may also be of gypsu m board . mineral fiber, glass fiber or other approved material:; securely fastened in place. Walls having parallel (I, staggered studs for sound-trallsmission co ntrol shall have stops of mineral fiber or glass fiber or ot/:· approved non-rigid materials.
Association of Structural Engineers of the Philippin es
CHAPTErl6 . Wood
4.
Dnlfl SlO pS shall be provided in the followi ng l oe
4.1
the grealest hori i'.olll:1I dime nsion docs not exceed 18.0
Ill .
Exception:
Floor-Cei ling Assemb lies.
4.1.1 Single-fami ly dwellings. As recommend ed in NSCP Volume 3 Oil I'lousing or when there is usablc space above and belqw the concealed space of :l llo0J"M ce iling assem bly in a singlcMfamily dwelling. draft stops shall bc il,stalled so that the ' area of the concealed space does not exceed 90 1112. Draft stops shal l divide the concealed space into approximate ly equal areas. 4 1.2 Two or more dwelling units and hotcls. Draft stops shall be installed in Ooor-ceiling asse mblies of building havi ng more than one dwe lling unit and in hote ls. Such draft stops shall be in line wi th wa lls
Where approved automatic sprinklers are j'Htalled. 'he 1 area between fhe draft STOpS may he 800 m and fhl' greatest horizontal dimensiolJ may I)(~ 30 m.
4.2.4 Draft stopping materials shall bc 110\ Icss than 12 mill gypsum board. 9 mill plywood . 9 111m Type M-2 particleboard or other approved mat erials adequately supported. Openings in Ihe partitions shall be protected by sc lr~cJos ing doo rs with au tomatic latches constructed as rcquired for lhe partitions. .. ;: '.' . , .. ' .: .... .., . ,. ..~
sc panll ing lenants from Cl.tch o ther a nd scpanui ng
tenants fro m other areas. 4.1.3 Olher uscs. Draft stops shall be installed in nOOI"M cei ling assemb lie s of buildings or ponions of buildings used for other than dwelling or hOle I occ upanci es .so that the area of concealed space docs not exceed 90 1ll 2. and so that the hori zo ntal dimension between stops docs /lot exceed 18.30111. Exception: Wh ere approved automatic sprinklers are installed within th e COli cealed space. the area between draft stops may be 270 nl. a nd the ho";zontal dimellsion may be 30
4.2 4.2. 1
f1l.
Attics. Si ll gle~ f;unil y
G 1t
dwellings. Refer to NSCP Volume 3 on
Housing. 4.2.2 Two or more dwelling unit and hotels. Drafts stops shall be installed in the attics, mansards, overhangs, false fro nt s set Ollt from walls and similar concealed spaces of buildings containing more than one dwelling unit and hotels. Such drafts stop shall be above and in line with walls separating tenants from each oth er and from other uses. Exceptions: Draft STOPS may be omitted along one of rhe corridor walls. provided draft stops at tenant separation walls extend to rh e remainillg corridor droll stop.
Where (lpproved sfJrillklerj' are illstalled, drajtstoppill8 may be as specified ill the exception below.
4.2. 3 Ot her UScs. Draft stops shall be install ed in ;:\Hi es. mansards. ovcr~ hangs , false fronts set Ollt from walls .and similar concealed spaces of building)) havin g uses other than dwellings or hotels so that th e area between draft stops does not exceed 270 m2 and
th
National Structural Code of tll('; Pllilipplnes 6 Edition Volume 1
;
6 ·12
CHAPTU16· Wood
shipla ps or joillls ::.hall he lapped hori zon tall y or otherwise 1l1acl(~ w:l!erpn)of 609.4 Shingles 609.1 General Exterior wood stud walls shal! be covered 011 the outside with the materials and in the :mlllllcr spccit1cJ jn this
section Or elsewhere ill this code. Studs or sheathing shall be covered on the outside face with a weather·resistive barrier when required. Exterior wall coverings or the minimum thickness specified in this section arc based upon a max imulll stud spacing of 400 mill unless ot herw ise specified. 609.2 Siding Solid wood sidin g shall ha ve lin average thickness
or 9 I11Ill
unless placed over sheathing permitted b y thi s code. Siding patterns known i~S rustic, drop siding or shiplap shall have an average thickness in place of not less than IS 111111 and shall have a minimum thickness measured not less than 9 111m. Bevel siding shall have a minimum thickness m eas ured at the butt section of" nol less than 11 mrn and a lip thi ckness of not less than 5 mm . Siding of lesser dimensions may be used, provided such wall covering is placed over Sheathing which conforms to the provisions specified elsewhere in this code.
All weatherboarding or siding shall be secu rely nailed to each slud wilh no( less (han one nail , or to solid 25 I1Ull n omi n ~11 wood sheathing or J 2 mm plywood ShclHhi ng or 13 111m particleboard sheathing with not Ie.... s than o ne li ne of na ils spaced nol more than 600 IIl1l1 on center in each piece of the weatherboarding or siding.
Wood board siding applied horizontally, diagonally or vertically shall be nailed to studs, nailing strips or blocking set maximum 600 mm on center. Fasteners shall be nails or screws with a penetration of not less than 40 mm illto studs. studs and wood sheathing combined, or blocking. Distance between suc h fastenings shall not exceed 600 111m for horizontally or vertically applied sidings and 800 111111 for diagonally applied sidings.
Of
Shakes
Wood shingles or shakes may be llsed for exterior wall covering, provided the framc of the structure is covered with building paper. All shingles or shakes attached to sheathing other than wood sheathing shall be secured with approved corrosion-resistant fa steners or 011 furring strips attached to the studs. Wood shi ngles Or shakes may be applied over fiberboard shingle backer and sheathing with annular grooved nails . The thi ckness or wood shingles Or shakes between wood nailing hoards shall not be less than 9 mill . Wood sh ingles or shakes o r siding Illay be nailed directl y to appro ved fi berboard nail base sheathing not less than 13 mill nominal thickn ess with annular grooved nail s. The weather cxposure or wood shingle Or shake siding lIsed on exterior ,>,.'alls shall not exceed maximum set forth in Table 6.6. 609.5 Particleboard When particleboard is used for coveri ng the exterior of outside walls, it shaU be of the M-I. M-S and M-2 Exterior Glue grades. Particleboard panel siding shall bc installed in accordance with Table 6.3 and 6.7. Pancl shall be gapped :3 mm and nails shall be spaced not less than 9 mm from edges and cnds of sheathing. Unless applied over 16 mIll net wood sheathing or 13 mm plywood sheathing or 13 mill pClrticleboard sheathing. joints shall occur over framing members and shall be cove red with a continuous wood batl' or joints shall be lapped horizonta ll y or ot herwise mad~ waterproof 10 thc sa ti sfaclion of the building official. Pal1icJcboard shall be sC
609.6 Hardboard When hardboard siding is used for coveri ng the outside of exterior walls, it shall conform to Table 6.8. Lap siding shall be installed horizontally and applied 10 sheathed or . unsheathed walls. Cornel' bracing shall be installed in conformance with Section 620.6. A weather-resistive barrier shall be install ed under the lap siding.
Where pl ywoud is used ror cove ring the ex teri or or otll::.idc walls, il shall be of (he exterior Iype not less Ihnn 9 Illill
Square-edged, non ~gro(}ved panels and shiplap grooved or nOll-grooved siding shall be applied vCl1 ica ll y to sheathed or un sheathed wa lls. Siding Ihal is grooved shall not be less than 6 nUll thick ill the groove.
thi ck. Plywood panel siding shall he inslalled in accordance with Table 6.5. Unless applied over 25 mm wood shea thing or 12 mm wood structural panel sheathing or 13 mill particleboard s heathing joints shall occur over framing members and' shall be protected with a continuous wood batten, approved caulking, flashing, vertical or horizontal
pcnetrate framing 38 mill. Lap si ding shal! overlap 25 I11 Ill minimulll and be nailed through both courses and il1lo framing members with nails located l3 mm from bottom ,~. the overlapped course. Square-edged non-grooved pane;';.
609.3PI),1\'00d
Nai l size and spaci ng shall follow Table .6.8 and shall
shall bc nailed 9 111m from the perimeter of the panel and intermediately into studs. Shiplap edge panel siding with
Associa ti on of Structural Engineers of the Philippirws
CHAPT En G . W O(Jd
I) IlUll shipl ap shall be Il
;... ' ....
All softwood wood structural panel s shall conform to the provisions of the previous Chapter and shall be installed in accorda;'{"cc with Table 6.3 Panels shall comply with UI3C Standard 23-3.
609.7 Nailing All faste ners used for thc attachmcnt of sidin g shall he of it corrosion-resistant type. ·:.:.:· !.
'j',.\.
!
., . ':; .~.... : ;.; ..\'
'.
.:..:.:<
.' .;;'Ji::.<-;,;- :-
.~::
.
:
,.\, .
(j - I ~:!
..... :.:.
111
National Structural Code of the Philippines 6 Edition Volume 1
6·14
CHAPTEr! 6 . Wood
SECTIoN 6.12 MECHANICALLY~LAMINATED. ;
FLOORSANr> DECKS
611.1 Structural 1'1001' Sheathing
Structural floor sheathing shall be design ed in accordffncc with the general provisions of' this code and the special provisions in thi s scction. Sheathing used as subflooring shall be de signed to SUPPO!1 al! loads specified in this code and shall be capable of su ppOJ1ing concentrated loads of not less than 1.33 kN without failure. The concemra(ed load shall be applied by a loaded disc, 75 mm or smaller in diameter. Flooring, including th e finish nom, ulldcrla yment l.Uld sub noo r. where used, shall meet the following requirem ents: I.
Deflection under uniform design load limited to 1/360 of the span between supportingjoi sls or beams.
2.
Detlec tion of fl ooring rei at; ve to joists under a 25 mm diam eter concentrated load of 0.90 kN limited to 3 min or less when loaded midwa y between supporting jois ts or beams nOI over 600 mm on ce nter and l/360 of lhe span for spans over 600 mm .
Floor sheathing conforming lo Ihe provisions or Tablcs 6.9, 6.10. 6 . 12. or 6. 13 shall
be deemed to
meet
the
requirements of thi s section. 611.2 Structural Roof Sheathing Structural roof sheal hing shall be designed in accordance with th e general provisions of this code and the special provisions in this section. Structural roof sheathing shall be designed to support all loads specified in thi s code and shall be capable of suppolling concentrated loads of not less than 1.33 kN without failure. The concentrated load shall be applied by a loaded disk, 75 mm or smaller in diamet er. Structural roof sheathing shall meet the following requiremellt : 1.
.... ..... .,
·;;'Y."',""
A I.uninuted :.:JJllber flo or or deck built up of wood mcmbers sct 011 edge. when rnecling the fOllowing requirements, may be designcd as u solid floor or roof deck of the same thi ckncss and continuous span may bc designed on the basis of the full crOSs section using the simple span moment coeflicicllI . Nail length shall not be less than 2~J/2 times the net thickness of each laminat ioll. When deck supports are 1.20 m on cc nter or less, side nai Is shall be spaced not more than 750 mm on centcr and staggered olle third of lhe spaci ng in adjaccnl laminations. Wh en supports arc spaced more 'than 1.20 III on ccnter, side nails sha ll be spaced not more than 450 mm on ccnter al lcrn.l1ely near lOp and bottom edges, and also stagge rcd onc th ird of Ihe spaci ng in adjacen t laminations. Two side nail s shall be used at each end of butt-jointed pieccs. L1minalions shall bc toe nailed to suppons with 20d or larger common nails. Whcn supports arc 1.20 III 0 11 center or less, alternate laminations shall be toe nailed to alternate suppons; when suppons arc spaced more than 1.20 m on cente r, alternate laminat ions shall be toenai led to every support. A single-spall deck shall have all laminations full length. A con tinuolls deck of two spans shall have not more than cvery fourth lamination spliced within quarter points adj oi ning support s.
Joints shall be closely butted over supports or staggered across the deck but within th e adjoining quarter spans. No lamination shall be spliccd more th an twice in any span .
Deflectio n und er uniform design live and dead load limited to 1/180 of the span between supportin g ruflcrs or beams and 11240 under live load onl y.
Roof sheathing conformi ng to th e provisions of Tables 6.9 or 6.10 and 6.11 shall be deem ed to meet th e requirements of thi s section. Wood' structu ral panel roof sheathing shall be bond cd by intennediate or exterior glue. Wood structural panel roof sheathin g exposed 011 the underside shall bc bonded wit h exterior glu e.
Association of Structural Engineers of the Philippines
SECTION 613 POST-BEAM CONNECTIONS Where post and beam or girder construction is used, (!11.~ design shall be ill accordance with Ihe provisions of Ihis code. Posi tive connection shaH be providccJ. to ensure a~ains[ upli~'t and lateral di splacement.
.'"
.
SECTION 614 WOOD SHEAR WALLS AND DIAPHRAGMS 614.1 Gelleral Unless permitted by the Building Official or by relevllnt pro v i s i n l ~s of NSCP Volume 3 Oil Housing. usc of' wood shear walls and diaphragms shall be limited to I !O 2-5torcy dwellings. Where applicable, succeeding provisions of this
Section shall be used as bases for their design. Particleboard vertical diaphragms and lumber and wood
structural panel horizonwl and veni ca! diaphragms may be used to resis t horizontal force s in horizontal and verticul distributing or resisting elements, provided the deflection in the plane of the diaphrag ms, as determined by calculations, tests or analogies drawn therefrom . does not exceed the permissible detlection o f attac hed distrib ut ing or resisting clcments. Permissible deflection shall be that defl ection up to which a diaphragm and any auachcd distri buting or resi sti ng element wi!! maintain its structural integrity under assumed load conditions, i.c. continue
10
support assumed loads
without da nge r 10 occ upant of the stmclurc.
Connecti ons and anchorages capable of resisting the design forces sha ll be provided between the diaphragms and the resisting elements. Openin gs in diaphragm which materially aff~(.;1 Iheir !) llcnglh shall be fully detailed on the plAns and shal! have their edges adequately reinforced to transfer all shearing s t]"I.!SSCS.
Size and shape of each horizontal diaphrngm and shear wall sha ll be limilcd as se l fOllh in Tablc 6.14. The height of
The maximum clear height from foundation to bottom of diaphragm framing above, or
2.
The maximulll clear height from top of diaphragm 10 boltom of diaphragm framing above.
The width of a shear wall shall be defined as the width
or
sheathing. Where shear walls wilh o penings arc designed for force transfer around the openings, the limitations of Table 6.14 shall apply to the overall shear wall including openings and to each wall pier at the side of an opening. The height of a wall pier shall be defined as the clear height of the pier at the side of an opening. The width of a wall pier shall be defined as the sheathed width of the pier at the
th
National Structural Code of the Pl1ilippines 6 Edltion Volume 1
6-16
CHAP"! Ef l 6 - W ooc1
side of HII opening. Des ign for force tran sfe r sha ll be based 011 a rtuiollal an al ysi s.
In buildings of wood-frame construction where rOlati on is provided for, the depth of the diaphragm Ilorma! to the open side shall 1I0 ( exceed 7.50 III or 2/3 the d ia phragm widt h. whichever is the smaller depth . Strai ght sheathi ng sh:Il J not be pCJ'lll i((cd 10 resis t shears in diaph rag ms acting in
rotat ion. Exceptions: 1.
2.
Olle-story, wood-framed structures willi the depth norma/to th e open side not greater than 7.50 m. may have a depth equa/to the width. Wh ere calculations show that diaphragm deflections caf! be tolerated, the depth normal to th e open end may be increased to a depth-Io-width ratio II0t greater Ihan J.5: J for diagorral sheathirrg or 2: J for special diagonal sheathed or plywood or particleboard diaph ragms.
I n nwsonry or con crete buildings, lumber and wood
stm ctural pa nel diaphragms shall not be considered as transmitting lateral forces by rotation. Diaphragm sheath in g nail s o r other approved sheathing connectors sha ll be driven nu~h but shall not fracture the surface of the sheathing .
614.2 Wood Members Resisting Horizontal Forces Contributed by Masonry and Concrete Wood mem bers sh all not be used to resist horizontal forces contributed by ma sonry or concrete construct ion in b ujld ings over one story in hei ght .
Exceptiolls:
1.
Wood floor and roof members may be used if! hariZOll/at trusses alld diaphragms to resist horizontal f orces imposed by wind, earthquake or earth pressure, provided such forces are not resisted by rotation of the truss or diaphragm.
2.
Ver/jeal wood sfructural panel-sheathed shear walls may be used to provide resistance to wind or ear/hquake forces in two-slOt}' buildings of masonry or concrete construction, provided the follo lVing requiremcfIls arp. met: 2.1 Story-to-story wall heights shall not exceed 3.6 meters. 2.2 Horizorllal diaphragm shafl not be considered to transmit lateral forces by rotation or camilever action.
2.3 Deflection of horizontal and vertical diaphragms
shall not permit per-slory deflection of supported
mm.·olll), or concrele walls 10 {!x("(!ed 0.005 lime.,· each story hei,;"t. 2.4 Wo od structural panel sliemhing in horizontal diaphragms shall havc all unsupported edgcs blocked. Wood sfruNliral panel sheathing for bOlh ,\'lOries of vertical diaphragms shall have all unsuppor!(~d edges blocked alld for Ih e lower walls have a minimum thickness of J2 mm. 2.5 There ,~'''all be no ollt·ol-plane horiz.ol/tal offsets between the first alld secon d stories of wood srructural pane! sh ear wails,
614 .3 Wood Diaphragms Wood Diaphragms shall conform wit h the fOllO wing guid clincs: 614.3. 1 Conventional Lumber Diaphragm Construction Such lumber diaphragms shall be made up of 25 mm nominal shcnthing boards laid at an angle of approx imatdy 45 degrees to supports. Sheat hin g boards shall be di rt~cil y nailed (0 each intennediate bearin g member with nO( less th an two 65mltl nails for 25 111m by 150 111m nominal boards and three 65111J1l nails for boards 200 mm or wider; and in add ition, three 65 mm nai ls and four 6S mill nai ls shall be used for 150 mm and 200 mm boards, respeclively,
at the diaphragm boundaries. End joints in adjacent boards shall be separated by at least one joist or stud space, and there shall be at leas t two boards between joints on the same support, Boundary members at edges of diaphragms shall be designed to resist direct te ns ile or comp res!; i"e
chord st resses and adequately tied together at corners,
614.3.2 Special Lumber Diaphragm Co nstru ction Special diagonally sheathed diaphragms shall conform :0 conventional construction and in addition, shaH have ;; il elements designed in conformance with the provisions of this code. Each chord or ponion thereof maybe considered as a beam loaded with a uniform load per meter equal to 50 percent of the unit shear due to diaphragm act ion, The load shall be assumed as acting norma! to the chord, in the plane of the diaphragm and eithe r towards or away from the diaphr
between structural members of the diaphragm such as the joists, studs and blocking, which se rve to transfer the ll ss lIIned load to Ihe sheathing, Special diagonally sheathed diaph rag ms shall includr. cOllventional diaph ragm s shea thed with two layers c( diagonal sheathin g at 90 degrees to each other and on the sa me face of the supportin g members.
Association of Structural Engineers of the Philippines
CHAPTEr·l E . Wood
(.14 ..1.3 \Vood Slrudul':tl ))and Dblphnl J.!. 1U
Horizo nlill and ve rtical diaphr:lgm s shea thed wi th wood slructural pimcis Illay be used 10 resist hori/.onwi rorces for horizontal di,lphraglll and for vertic al diaphragms, or may be calculated by principles of Jllechan i(~s without limi!atioll by usin g values of nail strength lHld wood structural pane! shear values as spec iii cd elsewhere in this code . Wood structural panels for horizontal diaphragms shall be as sct forth in Tablcs 6.10 and 6.11 for corresponding joist spacing "and londs. Wood structural panels in shear wnll s shall be :II least 8 mill thick for studs spaced 400 lllill on ccnter and 9 mm thick where studs arc spaced 600 mill 011 center. Maximum spa ns for wood struclUral panel subtloOl' ulldcr!aymcnt shall be as set forth in T
A ll boundary members shall be proportioned and spliced where necessa ry 10 transmit direct stresses. Framing members shall be at least 50 mm nominal in the dimension s to whi ch the plywood is attached. In general, pancl edges shall bear on the framing mcmbers and butt along th eir centerlines. Nails shall be placed not less than ]0 mrn ill from the panel edge, shall be spaced not more than ]50 min 011 center along panel edge bearings, and shall be firmly driven into the framing members. No unblocked panels less th an 300 mill wide shall be used .
Diaphragms with pa nel edges supportcd in acco rdance with Tables 6. I 0, 6. 11 and 6. J 2 shall not be considered as blocked diagrams unl ess blocking or ot her means of shear tran ~ fer is provided.
614.4 Particleboard Diaphragms Vertical diaphragms sheathed with pal1icleboard may be used to resist horizontal forces.
All boundary mcmbers shall be proportioned and spliced where necessa ry to transmit direct stresses. Framing members shall be at least 50 mm nominal in the dimension to which th e pa[1icleboard is attached. 111 general, panel edges shall bea r on the framing members an d butt along Ihei r ce nt erlines . Na ils shall be placed nol less than 9 mm in from Ihe panel edge, ~11iI1I he spaced nol more Ihan 150 I11 Ill 011 ccn ter along panel edge beari ngs, and sha ll be firmly driven into the framing members. Unblocked p;lIlcls less (h an 300 mm wide shall not be all owed or used. Diaphragms with panel edges supported in accordance with Table 6.13 shall not be considered as blocked diaphragms
unless blocki ng o r olhe r meilns of provided.
~ h car
G· 17
t n Ul ~fc r
is
614.5 Wood Shear Walls and Diaphnlgms iII Seismic 7-0'1<' 4 Section 614.).1 10614.5 .5 shall be used for wooden shear Willis and diaphragms dcsign for Seismic 7..\)Jlc 4 areas.
614.5.1 Scope Design and cOllstruction of wood shear walls and diaphragms in Seismic Zone 4, as allowed by provisions o f Seclion 6 14.1 and NSCP Volume 3 on Housin g, shall confo rm 10 the req ui rements oflhis sect ion. 614.5.2 Framing Col lector members shall be provided to transmit tension an d compress ion forcc~. Perimcter members <"11 opcnings s hall be provided and shall be dClailcd to di stribule the Shearing stresses. Diaphragm sheathing shu ll not be used to splice these members. Diaphrag m chords and tics shall be placed in, Or tangent to, the plane of the diaphragm framing unless it can be demonstrated that the moments, shear and deflections and deformations resulting from other arrangements can be tolerated.
614.5.3 Wood Structural Panel Wood structura l panels shall be manufact ured us ing ex terior glu e. -t Wood slnlclUrai panel diaphragms and shear walls shall be co nstlllcted with wood stnictural pa nel sheets not less th.m 1.20 III by 2.40 111 , except at boundaries and changes in fr:imi ng where minimum sheet dimension shall be 600 mm unless all edges of the undersized sheets are sUPPol1ed by framing members or blocking. Framing members or blocking shall be provided at the edges of all sheets in shear walls. Wood structural panel sheathing may be llsed for splicing members, other than those noted in Section 6 14 .5.2, where the additiona l nailing required to deve lop the transfer of forces wil l not cause cross-grain bendin g or cross-grai n tension in the nailed member.
614.5.4 Ilea,'), VVood Panels Diagonally sheathed panels uti lizing 50 I1l1l} nom inal boards may be used 10 r~li st the sa me pern~i ss i blc shear as ~5 Jlllll nominal lumber, ·exeept thm 16d n ~lI 1s shall be used lIls1ead of8d.
Nalional Structural Code of Ihe PI1 ilippines 6'" Edition Volum e 1
G· ! 8
C HI\P1t: H f:
Woc(i
Pallcls IHili zing strai ght dccking overlaid wit h plywood 10 resist shear forces usin g the SiUn c shear V.dll(.~ S a.~ permi ned for the wood stn!l:llIfal pan!.!! "Iolle.
may be uscd
Wood structural panel joints parallel to the decking shall be locilwd at least 25 /llJll offset from any parallel decking join!. Heavy decking panels utilizing dowel pins, or vcnit:ally laminated panels connected by nailing units 10 olle another, resist shear forces based 011 the permissible shear values of th eir connectors.
614.5.5I'articlebo,,,·d Pal1icleboard shall nOI be less th an Type M "Exteri or G lue" .
SECTION 615 STRESSES 615.1 General Except as herein provided, str(.~s~cs shall not l~xceed the allowable unit stresses for th e respective spcc ies and Li:ldc' \i(' fabricated products as se t forth in Table 6.1 and I'a: 6.15 for lumber. Values thcrein indicated are rek,· de::;ign values. All the tabulat ed design values (cxcep! (h e· ave rage modulu s of elasticity E) include reduct iolb s
Reference design v
Shear walls shall be shea thed wit h particleboard sheets not less than 1.20 III by 2.40 m except aI boundaries and changes in framing. The required nail size and spaci ng in
F. and a subscript ._. I for tensio n. c for compressio n, b for bending -.- is added to indicate the type of' st ress.
Table 6.3 apply to panel edges only. All panel edges shall be backed with 50 mm nominal or wider frailling . Sheets arc permitted to be installed either horizontally or vertically. For 9 111m particleboard sheets install ed with the
Reference design values for wood represent a starling point in the determination of the allowable stress for a pani n llar design. Adjusted ASD design va lues are determined hv multiplying the reference values by the appro])1 adjustement factors. A prime is added to the symbol o( i reference value 10 indicate th at th e necessary adjustJl:c:. i " have been applied to obtain the adjusted design value:
long dim ensi on parallel lO the studs spaced 600 111111 on cenler, nails shall be spaced at 150 mm on cent er along intermediate framing members. For all other co nditi ons, nai ls of th e sa me size shall be spaced at 300 llllll all center along intermediate framing members.
614.6 Fiberboard Sheathing Diaphragms Wood stud walls sheathed wit h fibe rboard shcathing may be used to resist hori zont al fo rces nOI exceeding Ihose SCI forth in this section. The fibcrboard sheat hing. 1.2 m by 2.4 Ill. shall be applied verticall y [Q wood stud s n OI less than 50 mm nominal in thi ckncss spaced 400 mm on cent er. Naili ng shall be provided at the perimeter of the sheathing board and at the intermediate studs. Blocking not less than 50 nUll nominal in thickness shall be provided at horizontal joints when wall height exceeds length of sheathing panel, and sheathing shall be fastened to the blocking with nails sized
spaced 75 mIn on centers each side of joint. Nails shall be spaced not less than 9 mm from edges and ends of shea thing, Marginal studs of shear wall s or shear-resisting clements shall be adequately anchored at the top and bottom and designed to resist all forces, The maximum height -width ratio shall be 1.5: I .
I~'
= F~ x
(product of adjustlnen t factors)
For a design to be acce ptable, the actual stress. i .c. It r!lH.'.,: be Jess lhan or eq ual to the adjustcd design va lue F,' :
615.1.1 Repetitive Memoer System A repetitive member system is defined as one that /Ja.': three (3) or more parallel members of Dimension lun -.l ; structural composite lumber; (2) Members spaced not lllUi ,; than 600mm; (3) Members connected together by a distributing clement such as roof, floor, or wall sheathi:· For a repetitive member system, Ihe reference Fi} rlW\' multiplied by a repetilive member factor, C, = 1.15. 1-(; olher framing systems, C, = 1.0.
'"
Va lues for species and grades not tahuhlled shall !';,' approved by the building official.
615.2 Stresses in Piles Used as Structural Mcmb(~rs Induced stresses for normal loading of round poles Pl"' . when used as a st ructural member, except modI;;;::'; " I elasticity which shall be the same as for sawll lum ber, sh~lll not exceed 60 percent of the basic unit working stresses WI' the species as forth in Table 6.1
Association of Structural Engineers of the Philippines
CHM' lTnG·Wou(i
6J5.3 Adjustlllcnl ofSlresscs
2.
The allowable uui! stresses specified in this chapter shall be su bject (0 applicahle adjustmen ts. 615.3. 1 Gcneral.
G1!J
When the ,1C(.;UIllUl tttcd durati oll of the full maximu m load during the life of the member docs not exceed the period indicated below, the val ues may he inc reased in the tabl e as follows :
--~ --r~ ---- ---- -'- '- -------- ---~---
The adjustments shall be as sc t forth in the footnotes to the approprialc Slrcss wbk~s and 1(; the requiremen ts or th is section: ::: load dunll;ofl faclor ;;;. wei servi ce fact or := size faclor ::: form factor :;: £Ial lI SC faclOr :;: support factor :;: incising «Iclor :;: temperature fact or :;: repetitive member factor := column stability factor = beam sla bili t y factor :;: slenderness factor =. coeffi cient of variation :::: volume factor These adjustment factors do not ap pl y design values.
to
al! reference
6 J5.3 .2 Preservative Treatment.
The values for wood press ure impregnat ed with an approved process and preservative need no adjustment for trea tment but arc subjected to ot her adj ustments.
615.3.3 Firc-Retardant Treatment The values for lumber and plywood pressu re imprcgnated with approved fire~ retard a nt chemi cals, including fastener value s, shall be recommended by ihe Ireater and su bmitted to the building official for approval. Submittal to the building official shall include all substanti ating data, Such y,llues shall be developed fl'Om approved test methods and procedurcs th at consider potential strength -reduction characteristics, including effects of elevated temperatures ilnd moisture.
Increase Period .- - - --- For seve n days dunllion. li S for roof 25% load s ---I :13.3% f.'or e,lr! hquake
Co
.~--- __:_ -__:_____c---- - - -. - - --
1.25 1.33
.--~- .-=---~=------'--.----'
For wind (for connect ions and fasteners)
1.33
60%
For wind (me mbers only)
1.60
100%
For impact
2.0
:n.J%
The fo regoing examples arc no! cumulative. For combined dural io n of loadings the resultant struc!urnl membe rs shall not be smaller than the required for the longer duration of loading. The duration of load factors in this ilem shall 11 0 1 appl y 10 compression·perpendicular-to- grain design values based on 1I deformation limi t, or 10 modulus of el(lslicit y. 3.
V'llues for normal loading conditions may be used without regard to im p(lct if the stress induced by impact does not exceed the val ues for normal loading.
615.3.5 Size Factor Adjustment When the depth of a rec tan gular sa wn lumber bending member 125 I11Ill or thicker exceeds 300 mm, the bending vHlues , 1"1" shall be multiplied by the siz.e factor, C,.., as determined by the Equatio n (615- 1):
_(300)"9
Cr - -
d
(6 15- 1)
where: Other adjustments are applicable, except thm the impact lo ud-duration factor shall not apply.
615.3.4 Duration of Load Values for wood and mecha ni cal fas tenings (when the ',yood delennines the load capacity) are subj ec ted adjustments based on (he following vi:l riati olls in the duration of load: !.
Where a member is fully stressed to the max imum allowable stress, either continuously or cumulatively, for more than 10 years under the conditions of maximum design load, the values shall not exceed 90 perce nt of those in the tabl es.
C" d
:::: size factor :::: depth of beam, mill
For be
National Structural Code of the Philippines 61h Edition Volume 1
6·20
CHAPTEH 6 Wooel
graded lumber 50 mm
(0
100 nun thi ck or to machinc-
strcss-rtllcd lumber.
When the slenderness factor C, is greaLer than I () but docs not exceed CI;. the all owable unit stress ill bending 1-"" sha ll he determined from the following equati on:
615.3.6 Slenderness Factor .Ind Flexural Stress. When the depth of a bending member exceed s it s breadth ,
F 'b
latera! support may be required and the slenderness factor Cs shall be calculated by the followin g Equation:
= F/J
[I - .3I. (~:t)·' l C' o
,
(615-3)
where:
(i7[ . =v/7
C,
(615-2)
where: Cs If
d b
:::;
slcndc mcss factor length of bea m, mill from the followin g tabl e
(615 ..
E
= mod ulus of elasti ci ty
Fb
= allowable unit stress ror extreme nbe!" in bend ing = allowable unit stress for cKtremc fibcr in bending. adjusted ror sle nd erncss.
= effective
F'/J
:::; depth of beam, 111m :::; breadth of beam, mm
When the slenderness factor C is greater than Ct but less than 50, the allowable unit stress in bending F';, shall be determined by the following Equation:
The effective lengths, I.. in the tabl e arc based on an Ijd rati o of 17. For oth er f../d ratios, these effective lengths may be multiplied by a factor equal to 0.85+2.55/(1,/d) except that thi s factor shall not apply to a single-s pan beam with equal end rnomems Or :::; 1.841u) or [0 a single span or cantilever beam with any load (ii' = 1.921u). When the slenderness facLor Cs doe s not exceed 10, the full allowable unit stress in bending Fb may be used . Effecti ve Length of Beams Type of Beam Span and Nature of Load
Value of Effecti ve Length, [,
Single-span beam, loael 1.611" concentrated at the center Single-span beam, uniforlnly 1.92/1/ distributed load Single-span beam. equ al end 1.84[. moments Cantilever beam. load 1.69[. concentrated at unsupported end Cantilever beam, uniformly 1.06[" distributed load Cantilever beam, uniformly distributed load with 1.69[" concentrated load at c'lIltilcver end Single-span or cantilever beam, 1.92[" . anY_
' _ 0.4 38E Fb,
C,-
(6 15-5)
In no case shaH C.. exceed 50. The design valu es for ex treme fiber in bending, F h , and modulus elasticity, E, used in the formulas for F'b shall 1:0(: modified to account for moisture service condition, duratiol l. of loading, temperature and type of treatmen t in accordance wi th the Section 615.3 except that the modification for size faclOl' shown in Secti on 6 15.3.5 shall not be used. Design va lues for extreme fiber in bending adjusted for slendemess factor, F'b. are not subject to further modifications for moisture service co ndition, duration of loading, temperature, type or treatment or size. The design value for ex treme fiber in bending. F'b, shall not exceed the full design value for ex treme fiber in bending. FI" modified as allowed in thi s section. including the size factor adjustment. When the compression edge of a beam is suppOited throughout its length to prevent its lateral di splacement, and the ends at points of bearing have lateral support to prevent rotation, th e unsupported lengt h 11/ may be taken as zero. When latera l SU ppOI1 is prov ided to prevent rotation at the
points of end beal;ng but no other lateral support is provided throu ghout th e length of the beam, the. un supported III is th e distance between such points of end bearing, or the length of th e cantilever. When a beam is provided with a lateral support to prevent rotational and lateral di splacement at intermediate points as . well as the ends, unwppo rted length lu is the di slilW;.; between such points of intennediate lateral su pport,
Association of Structural Engineers of the Philipp in es
CHAPTEFl G \Nood
(liS.3.7 Form Fador Adjustments The allowable unit strcss in bcnding for non-prismHtic,'
Illcmbers shall not exceed thc value established by mulliplyillg such stress hy the form faclOr Cj dctcrmincd liS follows:
Beam Section
Form Factor (Cj-)
Circular
1.180 1.414
Squ
0.81
1+[( 2~> r2~~~3 -Ijc,]
(615-6)
--_._- ) + 88 ( 25.4
where:
Ci C,: P
= form
raCIor
=s upport f'lclor =/',(6 -
(615-7 ) 8p + 3/) (I - q) + q
= f
615.3.9 Temperature The allow:lble unit stress for unlrcatl.'.d and prcscrvalivctreated wood specified in this chapler Hlld as modified in this sc!.:tion applies (0 uses within the ran ge or climatic tempcra ture ordina ri ly encoulltered in buildings. Wood members shall not be usctl in areas suhjcl:t to tempcratures above 66°(' unless the expos ure is infreque nt and any permanent loss in strengt h is accounted for in the design. The al lowable ·un i! streSS for lirc-rcl:u:dant-trealcd soliJ · . sawn lumber and plywood, including fas\Cners va lucs. subject to prolonged elevated temperatures from manufacturing or equipmcnt processes, bUI not exceeding 66°C, shall bc developed frol11 approved tes t methods that properl y consi der potential st rength-redu cti on cha racteri stics, including cffects of heat and moisture.
615.3.10 Moisture Service Condition Where sawn lumber and fastenings arc exposed 10 service conditions causing the wood to possess morc than 19 percent moisture colHent, the t:lbulmcd design vaiues 5htll l be reduccd as specified in Table 6.16
depth
of beam
= ratio of thickness of
eb or webs to the full width
o f beam
615.3.11 Boiled Joinls Bolt values used in conjunction with mctal side plates shaH be in accordance with Secl ion 619.
Thc form (newr adjustment shall be cumulative with the size factor adjustment, except for lumber I beams and box beams.
615.3.8 Modulus of Elasticil), Adjuslmenl Thc usc of avcrage modul us of elasticity E va lues is appropriate for the design of normal wood structural members and assemblies. In special applications where deflections arc critical to the stability of structures or structural componcnl s, and where exposcd to varying temperature and relative humidity under sustained loading co nditions, the average values of the modulus of elasticity E listed in Table 6.1 shall be reduced to account for variability. Coefficients of variation Cv in the modulus of elasticity E for lumber as foHows:
c,' Visllally graded !'i(lwn lumbor. Machine Sll'css*rated sawn lumber.
G ·:~ l
..(US ... 0.11
The average modulus or claslicily E valucs listed in the table shall be Illultiplied by 1*(\" or 1-1 .65Cv to oblain a modulus of elasticity E va lue exceeded by 84 percent or 95 percent indi vidual picces, re specti vely.
The duration-or-load adjustments specified in Section 615.3.4 do not apply to modulus of elaslicil y va lues.
National Structural Code
or the Philippines 6tl1 Edition Volume
1
6· "2
CHAPTEH G . Wood
616.4 Horizon(HI Sht':lf ill No(chcd Bemns Whcn rcclangular-shapcd girder. bl~.tlns or joists
SECTION 616 HORIZONTAL MEMBER DESIGN 616.1 Bel"n Span For simple beams, (he span shall be taken as the distance from fac!..: to face of support, plus one half the required l ength or bearing at each end; for continu'.1us beams. the
span is the distance between centers of Lea
j:"g~
on slJppon
over which the beam is continuous.
where: d d'
616.2 Flexure
= lOud depth of beam. = acwal dcpth of beilln lit 110(ch.
616.2.1 Circular Cross Section A beam of circuli'll' cross section may be assumed 10 ha ve
the same st ren gth in Oexure as a sq uare beam having the S;UllC cross-sectional area. If a circular beam is I
Whcn girder, beams or joists with circular cross section are notched al poillls of support Oil the tension side. they shall meet the design requirements Of lha! scction in bending .and in shear. The
616.2.2 Notching If possible, notching of beams should be avoided. NO[chcs in sawll lumber bending members shall not exceed oncsix th the depth of the member and shall not be loca ted in thc middle third of the spall. Where mcmbers arc notches at til e cnds, the notch depth shall not exceed onc- fourth the beam depth. The tension side of the sawn lumber bending members of 100 mill or greater nominal thickness shaH nOt be nOlched cxcept at ends of members. Cantilevered portions of beams less than 100 111111 in normal thickncss shall not be notched unless the red uced secti on properties and lumbe r defec ts afe considered in (he design. 616.2.3 L'ltC'rall"lolllcnt Distribution Lateral mOlllent distribution of a cOllcentf
616.3 Horizontal Shear The maximulll horizontal shear stress ill a solid-sawn wood shall not exceed that calculated by mean, of Equation (616-1):
l.
=
(-~l('-~!'l 2A" till
(616-3)
where: All = cross-sectional mea of l10tched member d
d"
= total depth of beam = actual depth of beam at nOlcil
For bending members with other th an rectangular or ci rcular cross section and notched at point of SUppOl1 on the tens io n side. the
(616-4) where:
3t' 2bd
f.
(616- 1)
artual unit shea r fl' shall !lot exceed the allow,lblc ror th e species and lIH.~ grade as givcn in Table 6. I adjusted for duration of loading. as provided in Section 615.3.4 . Tlh~
'-"hen calculating the shear force, \'. distribution or load 10
d
d' ('
= IOlal depth of bC
The shear ror the not ch on the compression side shall 1)(' further limited to the value determined for a beam of ,:. d' if e exceeds d'.
(116.5 Design of J()inl~ in Shear Eccc!l1ri c connector and bolted joints and beams SUppOil by conlleClOrs or bolt shal! be designed so thai li, in Equation (6 16-5) does not exceed the allowable un it stresses ill horizon ta l shear.
For hea ring of less thMI 150 mill in leng th an d not IIc;trcr than 75 111111 to the end of a member, the maximulll allowa ble load per SYUl.lfC olin ma y be oblain c,d b), multiplying the allowable unit stresses in compress ion perpendicular to grain by th e factor indicated by: (616·8)
. 3V j,. = ._._. 2b{{,
(616·5)
in whi ch !" is theJe))glh of bc
where: d,. (with co nnectors) = the deplh of the member less the dislance from the unloaded edge of the member to the nearest edge of the nearest con nector. d(' (with holts or lag screws)
The multiplying factors for indicated length of bearing on
such small areas as plates and washers may be: Lcngth
=- the depth of the member less
of
the distance from the unloaded edge of the member to the center of the nearest bolt or Jag screw. Al lowable unit stresses in shear for joint involving bolts or con nectors loaded perpendicular ( 0 gra in may be 50 percent . greater th,m (he horizontal shear values as set f011h in Table 6.1 and, provided thaI the joint occurs at least five times the depth of th e member frol~l its end. Wh en the joint is less than five times the depth of the member from its end, the included shear st ress is calculated by:
f
\'
=_~.~.J~) 2bd c
ld(.
(6 16·6)
and the 50 percent increase in design values for shear in joints docs not apply.
616.6 Compression Perpendicular to Grain In appli cati on where defonnation is cti ti cai, Equation (616-7) shall be lIsed to calculate the compression · pClpcndiculnr-to·grain design val ues. Fe.1' = 0.73 Fe.1
Bearing (mill) Factor
Fo'
The durati on of load modification factors give n in Section 615.3.4 shall not apply to comp rcssion -perpendicula:·-to· grain values for sawn lumber. The allowable unit stresses for compression perpendicular to grain ill Table Nos. 6.1 and 6.17 apply to bearings of any length at the ends of the beam and to all bearings 150 mill or more ill length at any other location.
38
50
100
75
or more
1.75
1.38
__
·"i.13._- . 1.10 1.25 _. 1.19 .
..
1.00
In joists sUPP0I1ed on a ribbon or ledger board and spiked to the studding, the allowable stress in compression perpendicular to grain may be increased 50 percent. 616.7 Lateral Support
Solid-sawn rectangular lumber beams, rafter and joist shall be suppoI1ed laterally 10 prevent rotation or lateral displacement in accordance with the following: ff the depth-to-thic kness dimensions, is:
nHio,
based
all
nom inal
I.
Two to one, or 2: I, no lateral support is required.
2.
Three to one, 3: I or four to one, 4: I, the ends shall be held in posi,ion, as by [ull·dep,h solid blocking, bridging, nailing or bolting to other framing members, approved hangers or other acceptable means.
3.
Five to one, 5: 1. one edge shall be held in line for its entire length.
4.
Six to one, 6:1 , bridging, full·tiepth solid bloc king or cross bracing shall be installed at interval s not exceedi ng 2.4 meters unless:
(616-7)
compression-pcrpendicu iar-to-grain values from Tables 6. 1 ::: critical compressioll·pe rpendicular-to-grain value
25
In us ing the preceding equation and table for round washers or bearing areas, usc a length equal 10 the diameter.
where: Fel
150 13
Both edges of the member arc held in line or,
The co mpression edge of the me mber is support ed throughout its length 10 prevent lateral displnccmcm, as by adequate sheathing or sub-flooring, and the ends and all points of bearing have lateral support to prevent rotation.
Nalional Siruclural Code of the Philippines 6'" Edilion Volu me 1
.
6·2~
5.
CI1AI'TE'li r; . Wood
Seven 10 one, 7: I, both edges shall be held ill line for
th eir cn{in:~ Icngth.
SEC'llION'6 p . ' ..
GOLitMN ;p£SIGN "
If a heam is subj ect 10 both fl ex ure ~l lld co mpressio n parallel to gra in, the ratio may be as mu ch as 5: I if one edge is held tlrmly in!inc. If under any combil1atioll of load the un braced edge of the member is in tension, the rati o may be 6: I .
In lieu of providing lateral support by the methods specified in items 2 th rough 5 above, the ;IIJOWllhlc stresses shall be reduced by the slenderness factor sci forth in Secti on 615.).6.
616.8 Lateral Support of Arches, Co mpression Chords of Trusses and Studs
617.1 Column C lassifications
617.1.1 Simple Solid-Wood Columns Simple column consist of a single piece or of pieces properly glucd together to (W!ll a Si~lglc mcmber.
617.1.2 Spaced Column , Co nn ector Joined Spaced columlls arc formed of two Of mo re indi vi dual members with th eir longitudinal axcs parallel, separated at the ends and middl e points of their Icngth by blocking and joined at the ends by timber connectors capable of developing the required shear resistancc.
Where roof jni.l;( or purJins are llscd between mehes or
compression chords, th e largest value of I)d, calculated using the depth of the arch or compression chord or
calculated using the breadt h (Icast d i men~ i o ll ) of the arch or co mpressioll chord bctween poillts of inlcnni nent lateral suppOI1, shall be uscd. TIIC roof joist o r purlins shall be placed to account for shrinkage (for example, by placing th e upper edge~ of unseasoned joist approxi mately 5 percent of the joist depth above the lOpS of the arch or chord) but also placed Jow enough to provide adequate lateral support. Where roof joist or purlins are pl aced on top of an arch Or co mpression chord and are secu rely fastened to the arch o r compression chord, the largest va lu e of !,Jd, calcu lated using the depth of the arch or compression chord or calculated using the breadth (least dimension) of the arch or compression chord between points of intermittent lateral support. shall be used. Where planks are placed on top of an arch or compression chord and securely fastened ( 0 the arch or compressio n chord, or whe n sheathing is nai led properly to the top chord of trussed rafter, the depth rather Ihan Ihe breadlh of Ihe
arch, compressio n chord or trussed raflcr may be used as the least dimension in determinin g Vd. Where stud walls in light~frame construction are adequ ately sheathed on at least one side, the depth rather than breadth of the stud, may be laken as the least dimension in calculat in g the Ijd ratio.
617.1.3 Built-Up Columns Bu ilt-u p colu mn s. other IIwn cOllneclof-joined spaced col umns and glued- laminated columns, ~ h all n Ol bc designed as solid colullllls. 617.1.4 Glulam Columns Gi lliam columns shall be composed of at least four laminations, with their grain essentially parallel. Lil1lit~ltion on lid Ratio For simple sol id columns. /1 d shall not exceed SO.
617.2
617.3 Simple Solid·Column Design The cffective column length, I,. shall be used in design Eq uations given in thi s sec tion. The effective column length. I, shall be detcrmincd in accordance with good engineering practice. Actu al column len gth, I, may be multiplied by the factors given in the following table 10 determine effective column length, I". Allowable unit stresses in newton per square millimeter of cross-sectional area of sq uare or rectangu lar simple solid columns shall be determined by the followin g formulas, but such unit stresses shall not exceed values for co mpression, parallel 10 gra in Fe in Table 6. 1 adjusted in accordance wilh provisio n of th is secti oll.
(6J 7·1)
Associalion of Structural
Engin~ers
of the Pililippincs
CHAPTEH E · Wood
SUppO!1 Conditions: Largc end fixed, small cnd unsuppoltcd Small end fixed, large end un supported
where:
= 0.8 for sawn lumber. for round timber piles.
c·
= 0.85 _
r, -
K"L'
(i;-i--;;Y
BOIh ends simply supported: Tapered toward one end Tapered toward both ends
= E~ilcr <.:ritica! buckli ng stress for columns Fc* = lahuhllcd co mpress ion design value multiplied by all of the ,Ipplicab!c adjustment L1 ctors. gel:" = 0.3 for vis uaJl y graded l u m~}er. Kc£ = 0.418 ror products such as machine S (rC s~H·i.He d sawn lumber.
...
_--- ---._- - _. _.
.Ii". , ~ ,, ,,
,, ,,, ,, ,,
Buckling Mo(h~!
,
t ~
Ii
\
••
, , ,,, , ,,,
, ,,,
•!
•
t
1.00
2. 10
\ \
Ji. II,
t
t
0.65
O.SO
,p
, ,, , ,, ,,
, ,,, ,, ,, ,
, ,,
\ . \ \
~
... i
bQCIdin«
...... -, K,
I. 20
The design of a column of rou nd cross section shall be based on lhe design c,llculali olls for a squa re colu mn 01" the same cross ~sectional area and having the so\!l1c degree of
,
,, ,,, ,
,, ,,, ,
2.'
('Ilattd
..,.
End Condition
Code
I User Note:
Rotation fi x.
.,.Y'
Rotzrti.ou frcc , traNiatiotl fIXed
f
Rotation fr ee, lIanslation free
Rotation fixcd, translation free
t, = K; I
617.4 Tapered Columns
When designi ng a tapered colum n with a rectangular cross section, tapered at one or both ends, the representative dimension, dul' fo r each face of the column slwll he deri ved as foll ows: d n ·p
= dm in + {cimax - dmil,Ha-.Q. 15 ( [·dmifl I dm"J1
a = 0.50 a = 0.70
(617-3)
condltto,.. approJj.
-
a = 0.70 a = 0.30
For all other SU pp011 conditi ons:
Do ..... f.dot,
(-j·?S
(61 7-2)
where: thc minimum dimension, d, for that face of the column d"'lI.l· = tbe maximum di mension, d, for that face of 'he colu mn
d"'ifl
th
National Structural Code of the Philippines 6 Edition Volume 1
6·26
CHAPTU! G . Wood
and (2 ) w he n checkin g the design perpendic ular 10 the plane of bend ing the ~Ie ndt~rn('.s~ nHio. Uti. in -Ihe plan e o f bending shall be \lsed 10 <.:ldculatc F', and J shall be SCi.
equal
618.1 Flexul'e and Axial Tension Members subjected 10 bOI!~ .-lcxu['c .and axial tension shall be so proportioned that (6 18·1 ) <
and
Iv - I, I~ **
(618·2)
10
zero.
6JX,3 Spaced ColulIlIls In the case of spaced columns, this co mbined stress formula maybe applied only if the bending is in a direction paralIcl to the greater d of the individual member. 618.4 Truss Compression Chords Effect of buckling of a 50 mill by 100 mill or smaller tIllSS compression chord hav ing effec tive bucklin g lengths or 2.40 III or less and wi th 9 mm or thicker pl ywood sheathing nailed to the IUlITOW face of the chord in accordance with the appropriate slandllrds 5h"1 1l be determined from the equil tion:
C,.
= 1 + O!,2!,
where:
F
*'
EO.05
"
applicable adjustment factors except beam stabi Jjt y
factor. CI.
= Fb ** =
F/ f,
ft,
(618-6)
tabulated bending design value multiplied by all
F (C")(C,,,)(C,)(C,.)(C)(C,) for sawlllu",ber Fb" (C,,)(CM)(C,) (C,.) for glulam tabulated bending design value multiplied by all
applicable adjustment factor except volu me faclor. Cy . = Fv (CO)(CM)(C,)(CL)(C,)(C,)(C,) for sawll lumber = F. (Co)(CM)(C,)(CLl for gilliam = allowable tension design value parallel to grain = actua l unit stress in ten sion paraJl ellO grai n. = actual unit st ress for extreme fiber in bending.
618.2 Flexure and Axial Compression Members subj ected to both flexure and axial compression shall be proportiolled that
J.L
Ib'
F' c F' I>~
-
S I
(6 18-3)
lie
where: Cr
"'" buckling of the stiffness factor "'" 0.819£ for rnachine-strcss·nucd lumber f,. .,"'" effective bucklin g length used in design of chord for compression loading Eo.o.l = 0.589E for visually graded lumber £ = Modulus of elastici ty from tables of allowable UTlit stress. N/mmJ
The va lues of C r determined from th is eq uati on arc for wood seasoned to a moi sture content of 19 percent or less al the time th e plywood is nailed to the chord. For wood that is unseasoned at the time of pl ywood auachmcnt, Cr slwlJ be determined from the Equalion (618·7): ,
CT
=
1+0.331, EO.05
(618-7)
For chords with an effective buckling length greater thall 2.40 Ill, C shall be taken as the value for a chord having an effective lenglh of 2.40 m.
The value of J shall be derived as /, ! d -II
J = -'---
K-II
-_. E K =0.67 1 JF,
(6 18-4)
(6 18-5)
except that J shall not be less than zero nor greater thull Olle (0 5!, 1$ 1).
F'e and K shall be determined in accordance with the provision in Section 617.3, except (I) when checking the design in the plane of bending the slenderness ratio, Vd, in the plane of bending shall be lIsed to calculate F'e and J
The buckling stiffness factor does not appJy to shari col umns or trusses used un der wet co nditions. The {Il1owablc unit co mpress ive stress $hall be modified by the buckling stiffness factor whcn a truss chord is subjected (0 combined fle xure an d com pression and the bendi ng moment in th e di rection thaI induces compression slres:,,--, in the chord face to wh ich the plywood is attached. The buckling stiffness factor CT shall apply as follows: Short column ( /, 1 d of II or less ):
Associat ion of Structural Engineers of the Philippines
CHAPTEH G . Wood
6·29
620.4.2 Veneer Anchored masonry and sto lle wa ll veneer shall not exceed J 25 Illlll ill thickness.
620.1 Genel'al The requireme nts in this section arc intend ed for conventional li g ht ~fram c construction. Olher methods may be used provided a satisfactory design is submitted showing compliance wi th other provisions of this code.
620.4.3 Unusually Shaped Buildiugs When building is of an unusual shape as defined in Section 620.5.3, buildings of light-frame co nstructio n in Seismic L,one 2 shall have a latcral~force~ rcs i stillg sys tem designed to resist the forces specified in Chapter 2. 620.5 Additional Requirements for Con ventional Construction in Seismic lAne 4
Onl y the fol/owing occupancies ma y be cons tnlClcd in
620.5.1 Braced Wall Lines
accorda nce wit h (his di vision: I.
2.
O n c~,
In areas under Seismi c Zone 4 and where the basic wind speed exceeds 125 kph. hui Idings shall be provided with
two- o r three-story residential buildings.
IV bui ldings, us
ex te rior and interior hnlccd wa ll lines not exceeding 7.50111
defined in Table 103-1, when constructed on a slah -ollgrade floor.
O ne -story Occup.lncy Category
on cen ter in both the longitudi nal and transverse directions in each story.
3.
Category V Occupancies
Exception:
4.
Top-story walls and roofs of Occupancy Ca tegory IV buildings not exceeding two storeys of wood framin g.
5.
Interior non-load bearing partitions, ceilings and curtain wa ll s in all occ upancies.
In one- and two-stmy dwellings and lodging houses, imerior braced wall line spacillg may be increased to lIot more than 10.0 m on center in order to accomnwdate one single room per dwelling unit flot exceeding 84.0 m2• The building official may require additional walls to contaill braced panels when this exception is used.
Olher approved repet itive wood mem bers may be llsed in
lieu of solid-sawn lumber in conventional constluction provided these members com ply with the provisions of thi s code. 620.2 Design of Portions
When a building of otherwise conventio nal constructi on contains
non -conventi911aJ
structural
elemen ts,
those
elements shall be designed in accordance with Section "Rationality of Design Method" on the previous chapter.
Oil
620.3 Additional Requirements for Conventional Construction in High M wind Areas Provisions for conven tional conSiIllction in high ~willd areas shan apply when specifically adopted. 620.4 Additional Requirements for Conventional Construction in Seismic Zone 2
620.5.2 Veneer Anc hored masonry and stolle wa ll ve neer shall 1I0 t exceed 125 mill in thi ckness and shall not extend above the fi rst sto ry. 620.5.3 Unusually Shaped Buildings When of unusual shape, build ings of light-frame construction shall have a latcraJ-force-rc!iisting sys tem designed to resist the forces specified in Chapter 2. One or mOre of the following shall be considercd to constitute an llnusual shape: 620.5.3.1 When exterior braced wall panels, as required by Section 620.10.3, arc not in one plane veltically from the foundat ion to the upperm ost story in which they arc required.
Exceptions:
620.4 .1 Braced Wall Lines In areas under Seismic Zone 2 ;:lIld whe re the basic wind speed obt'li ned frolll Figure 207-) is not gre ater than 125 kph, buildings shall be provided with exterior tl nd in terior braced wall lines not exceeding 10.0 m on center in bot h the longitudinal and transverse directions in each story.
Floors with can tilel'e!:'; or setbacks not exceeding/ow· times the nominal depth of the floor joists may support braced lVall panels provided:
1.
Floor joists are 50 mm by 250 mm or larger and spaced at not more thall 400 mm 011 center.
2.
The ratio of the back span to the cantilever is at least 2 to 1.
National Structural Code Df the Philippines 6'" Edition Volume 1
6 ·30
CHAPTEH 6 . Wood
3.
Floor joists at ends of braced IVall panels are doubled.
4.
A continuous rim joists is cOflnected to ends of all cantilevered joists. 1'liC rim joist may be spliced using (J metal fie no/less than 1.47 mm (/6 galvaniz.ed gage)
and 38111111 wide/astened with six 16 d nails. 5.
Gravity loads carried at the end of cantilevered joists Gre limited to uniform wall and roof load alld the reactions/rm!z headers having a span of 2.40 m or less.
height, .!l1 illlerior braced waJl p;'lIlcls shall be supported on continuous fOllndations. Exception: Two-story buildings may have interior braced wall lines supported on continuous jOUlu/mions al il/tervals he....· exceeding 15.0 m. provided: 1.
Cripple l,<'!al! h(!ighr does nOl exceed 1.20 m.
2.
First - floor braced wall panel~i are supported ,.,'. doubled floor joist, COllliIZU O U~' blocking or FO{ir beams.
3.
Dislallce between bracing lines does not exceed li l 'i, " _' the buildillg width parallel (0 lhe braced wall line.
620.5.3.2 When a section of floor or roof is no! lmcrally Sllppol1cd by braced wall Jines on all edges.
Exception: PoriioTIS of rooff or floors which do 110/ support braced waJ/ panels above may extend up to J .80 111 beyond a braced wall/ine. 620.5.3.3 When the end of a required braced wall pallel exte nds more than 300 mm over lin opening in the wall below. This provision is applicable to braced wall pancls offsc t in plane and to braced wall panels offse t ou t of plane as permitted by Section 620.5.3.1.
F..xceprion: Braced wall panels may extend over an opening 1101 more than 2.40 nl. in width when the header is a 100 mm by 300 mm or larger member.
620.5.3.4 When an openi ng ill a floor or roof exceeds the lesser of 3.60 m or 50 percent of the least fl oor or roof dimension.
620.6 Girders Unless ol herwise permitted by pro visions in NSCP V Ol:J!:1 , ~ 3 on I-l ousing, girders for single-story construclinJ'r ',r girde rs supporting loads frolll 11 single nOol' shall not be- k:-::s Ihan lOOmm by 150 IlUll for spans 1.80 III or less, provided that girders are spaced not more than 2.40 Jll on center. Other girders shall be designed to suppo rt the I()ad~,; specified in this code. Gi rder end joints shall occur over supports. When a girder is spliced Ove r a support, adequate tic shall be provided. The end of beams or gillh:; s suppo!1ed Oil masonry or concre te shall not have less lll:ii! 75 111m of bearing. 620.7 Floor Joist s 620.7.1 General The limits of defects by grade ill joists and plalli;s fur
620.5.3.5 Construct ion where pOrl ions of a nODI' level are verticall y offset such that the framing members Oil either side of the offset cannol be lapped or lied lOgcthcr in an approved manner as req uired by Section 620.7 .3. Exception:
Framing supported directly by foundations. 620.5.3.6 When braced wall lines do not occur in two perpendicular directions.
620.5.3.7 Other config urations which, in the opinion of th e building official, create irregularities or di scontinuities wh ich arc 1101 addressed by this Section. 620.5.4 Lumber Roof Decks
Lumber roof decks shall have solid shemhing. 620.5.5 Interior Braced Wall Support
In one-story buildings, interior braced wall lines shalt be
suppol1ed on continuous foundation s at intervals not exceedi ng 15.0
111.
In buildings more than one-story in
seasoned wood arc set forth in Table 6,15. 620.7.2 Bearing Except where supported on a 25 mill by 100 mm ! ;; ,1-:-'1: strip and nailed to th e adjoining stud, the ends of eaell shall not have less than 38 Illlll of bearing on wood or metal, or less than 75 mm on masonry. 620.7.3 Framing Details Jois ts shall be supported laterally {It th e ends and at (";;" 11 support by solid blocking ex cept wh ere th e ends or .! <) arc nailed to a header, band or rim joi st or to an iHI.i o~lLJ ',i: stud or by other
Notches on the ends of joists shall 1101 exceed one-fou rth the joist depth . Holes bored in joist,; shall not be wit hi n ~n mill of the top or bottom of the joist and the diamch': l .,' ") such hole shall not exceed one-third the depth of {[;\. jl; )sL Notches in the top or bottom of joists shall not eX
Associa tion of Structu ra l Engineers of the Philippines
C HAPTE.!' G . WooO
Joist framing from opposite sides o/" a beam. gintcr or pani tioll ,.,hall he lapped al Jc.ast 75 mm or the opposing joists shall he tied together In an 'lpprovcd manner. Jo is ts frelllling il1lo the side or a wood girdcr shall be supp(mcd by framing ,lIlellors or nil ledger strips IH)[ less tlWll 50 mill by 50 mill. 620.7.4 Framing Around Openings Trimmer amI header joists shall be doubled, or of lumber of equivalent cross sec tion, when the span of the header exceeds J .20 Ill. The ends of header joists more than 1.80 m lon g shall be su pported by framing anchors or joist hallgers unl ess bea ring on a beam, panition or wall. Tail joists over 3.60 III long shall be supported at header by framing anchors or 011 ledger strips not less th'lIl 50 I11I1l by
G·31
620.8,3 Plnnk Flooring Plank floo ring shall be designed in ;Icconlancc with the genera! pro vis ions of thi s codc . In lieu of such dcsign, 50 Jll1l1 tongue -and -groove planking Illay be llsed in accordance with Tabl e 6.22. Joints in such planking may bc 'randomly spaced, provided th e system is applied to not less than three continuous spuns, planks arc center-matched and cnd~1l1atched or spli ncd, eac h. rlank bears on at least one support and joints are ~;c para.tl~d by at least 600 mm in adjacent pieces. 25 mill nominal strip square-edged flooring; 13 mm tongue·and -groove flooring or 9 mill wood structural panel shall be applied at right angles 10 Ihe span of Ihe planks. The 9 mm plywood shall be applied with the face grain at right angles lO the span of the planks.
50mm.
620.7.5 Supporting Bearing P~lrtjtions Bearing partitions perpendicular to joists shall not be offset from support ing girders, walls or partitions more than the joist deplh . Joists under and parallel doubled .
to
bearing partitions shall be
620.7.6 Blocking Floor joists shall be blocked when required by the provisions of Section 620.7.3.
620.8.4 Particleboard Where used (IS structural subOooring or as combined subfloor underlaymcnt, particleboard shall be as set f0I1h in Table 6.13.
620.9 P~lrticlehoard Underlaymcnt In accordance with approved recognized· standards, particleboard floor undcrlayment shall co nform to Type PBU . Underlayment shall not be less than 6 mm in thi ckness and shall be identified by the grade mark of an approved inspection agency. Underlayment shall be installed in accordance with this code and as recommended by the manufacturer.
620.8 SubOoOling 620.10 Wall Framing 620.8.1 Lumber Subnoor 620.10.1 Size, Height and Spacing
Sheathing used as a st ructural sub-floor simi I conform to the limitations set (ol1h in Table 6.9.
'Jlle size. height and spacing of studs shall be in accordance
Joints in subtlooring shall occur over SUpp0I1S unless cndmatched lumber is used in which case each piece shall bear on at least two jOists.
wit h Table 6.23 except that utility grade studs shall not be spaced more than 400 mm on center, or sup port more than a roof and ceiling, or exceed 2.40 111 in height for exterior walls and load-bearing walls or 3.00 m for interior non load·bearing walls.
Subflooring may be omitted when joist spacing does not exceed 400 111111 and 25 mm nominal tongue-and-groove wood strip flooring is applied perpendicular to the joi sts.
620.10.2 Framing Details
620.8.2 Wood Structural I'"nels \:Vhere used as structural sub nooring, wood st ru<.:w ral panels s hall be ns sci forlh ill Tables G. 1O and G. II . \Vooel stru ctural panel co mbination subfloor 1I1lde ri ayment shall ha ve maximum spans as set fort h ill Table 6.12. When wood structu ral pane) noOl"s are glued to joists with an adhesive in accordance with the adhesive manufacturer's directions, fasteners may be spaced a maximum of 300 mm on center at all supports.
St ud s shall be placed with th eir wid e dimension perpendicular to the wall. Not less Ihan three st uds shall be insta lled at each corner of an exterior w,l l1 . L::xceptiolls:
At comers, a third stud may be omifled lhrough (he use of wood spacers or backup cleats of 9 mm wood structural pallc/, 9 111111 Type M "Exterior Glue" particle-board, 25 mm lumber or other approved devices rliat will serve as an adequate backing for the attachment of facing materials. Where fire resistance ratings or shear values are involved,
Natio~,al Structural Code of (he Philippines 6"; Edi(ion Volume 1
6·32
CHAPT"" 6 . Wood
than 9 ml11 for (lOn I11Ill stud spacirlt in
wood spacers, backup cleats or other devices shall flot be used unless specifically approved for Stich use. Dearing and exterior w
A single top plote
lIIay
When bearin g studs arc spaced at 600 111m intervals and EOr plates arc less than 50 nun by 150 mm or 70 mill by 100
111m members and when the floor joists. floor tl1lSSCS or roof tru sses which they support are spaced at more than 406 Illlll intervals, such joists or tmsses sha ll bear with in 125 mm of the studs beneath or a third plate shall be installed. Interior nonbearing partitions may be capped with a single top plate in stalled to provide overlapping at corners and at interscctions with other walls and pal1itions. The plate shall be continuously tied at joints by solid blocking al least 400 mill in length and equal in size to the plate or by 3 min by 38 111m metal ti es with spliced sections fastened with two 16d nails on each side of the joint.
Studs shall have full bearing on a plate or sill not less than 50 mill in thickness having a width not less than that of rhe wall studs.
620.10.3 Bracing Braced wall lines shall consists of braced wall panels which meet the requirements for location, type and amount of bracing specified in Table 6.24 and arc in line or offset from each other by not more than 1.20 111. Braced wall panels shall start at not more than 2.40 m from each end of a braced wall linc. All braced wall panels shall be clearly indicated on Ihe plans. Constnu.:tion of braced wall panels shaIl bl! by one of the (oIlowing method s:
2.
3.
Fiberboard sheathing 1.20 III by 2.40 III panels 110t less than 13 Illlllihick applied vCrl icall y on studs spaced not over 406 mill on center whcn installed il) accordance with Seclion614 .6 and Tablc6.27.
5.
Gypsum board (sheathing 13 mrn thi ck by 1.20 III wide, wallboard or veneer base) 011 studs spaced not over 600 /llill 011 center and nailed at 175 mill on center with nail s as required by Table 6.28.
6.
Particleboard wall sheathing panels where installed in accordance with Table 6.29.
7.
Portland cement plaster on studs spaced 400 mm on center installcd in accordance with Table 6.28.
8.
f[~lrdboard panel sidi ng when installed in accor
be used, provided Ihe plate is
adequately tied al joints, comers and intersecting walls by at least the equivalent of 75 111111 by J50 mm by 0.9 111111 galvanized sleel that is nailed to each wall or segmenl of wall by six 8d nails or equivalent, provided the rafters, joists or tmsses are centered over the studs with a tolerance of flO more than 25 mm.
I.
4.
Nominal 25 111m by 100 mill con tinllous diagonal braces let into 101" and bott om plates and intervenin g studs, placed at an angle not more than 60 degrees or less thall 45 degrees from the horizontal, and attached to the framing ill conformance with Table 6.3. Wood boards of 16 mm net minimum thickness applied diagon ally on studs spaced not over 600 mm on center. Wood structural panel sheathing with a thickness nOI
less than 8 111m for 400 mm stud spac ing and not less
For cripple wall bracing. sec Section 620.10.5. For Methods
2, 3, 4, 6 and 8, each braced panel rnust be at least 1.20
111 in Icngth, covering three stud spaces where studs are spaced 400 111m apart and covering two stud spaces where studs arc sp~\ccd 600 mill apart.
For Mcthod 5, each braced wall pancl must be at least 2.40 III in Icnglh when applied 1O onc facc of a braced wall panel and 1.20 m whcn applied to both faces. All vcr1ical joints of pane.! sheathing shall OCCllr over studs. Horizontal joints shall occu r over blocking equal ill size to the studding except where waived by the installation requirements for the speci fic sheathing materials.
Braced wall pancl sole plates shall be nailed to the floo r framing and top plates shall be connected to the framing above in accordance with Table 6.3. SiIls shaIl be bolted to the foundation or slab. Where joists are perpendicular to braced wall lines above, blocking shall be provided under and in line with the braced wall panels. 620.10.4 Alternate flraced Wall Panels Any braced wall pnllci req uired by Sectioll 620. 10.3 lIla y be re placed by an nlternatc brnced wall panel cOllstruc ted jl~ accordance with thc following: 1.
In one-story buildings, each panel shall have a length of not less thnn 800 111m and a height of not more than 3.0!ll. Each pan el shall be sheathed 011 o ne face with 9 mm plywood sheathing nailed with 65mm common or galvanized box nails in accordance with Table 6.3 and blocked at all plywood edges. Two anchor bolts installed shall be provided in each panel. Anchor bolts shaIl be placed at panel quarter points. Each panel end stud shall have a tic-down device fastened to the
Association of Structural Engineets of the Pililippines
CHAP '!'En 6 . Woo(1
2.
G
foundtlti oll. capahle of providing un approved uplifl capaci ty of not less Ihan 820 kg. The lie-dow n device stltllJ be installed ill llccordancc with the manu fac turer' s recommendati ons. The panels shall be" suppol1cd direcll y on a foundation or on floor framin g SLJPIJO l1Cd directly On a foundation which is continuous acroS5 [he entire length of the braced wall line. This foundati on shall be reinforced with not less than one 12 IllIl1 bar lOp ilnd bOlIOfll.
joisls unocrnc:H h stich parti tions slwll he doubled and spaced 10 perm it the passllge of such pi pes and shall be briuged. Where plumbing, hea ting or olher pipe.Ii arc placed in Or paI11 y in a partition, necessit ating the cuttin g of the soles or plales, a metal tic not less tl wn J.4 7 mm (16 galvanized gage) and 38 mill wid e shall be fastened to each plate across and to each side of' th e opening with not less than six 16 d nails.
In the first story of two-story buildings, each braced wall panel shall be in accordance with Secti on 620. 10.4, item I, except that the plywood sheathin g shall be provided on both faces, Ihree anchor bolts shall be placed alone-fifth points, and tic-down device uplift capacit y shall not be Jess than 1360 kg.
620.10.8 Bridging Unless covered by interior or ex teri or wa ll coverings or sheathing meeting the minimum requirements of' this code, all stud partitions or walls with stu ds ha ving a hci g ht - to ~ least thi ckness rati o ex~ceedill g 50 shall ha ve bridging not less than 50 mm in thickness and of Ihe same width as the studs fitted SJlugl y and nailed thereto to provide adequate lateral support .
620.10.5 Cripple Walls FOllndalion cripple wall s shall be framed of studs fl ot less ill size than the studding above with a minimum length of 350 mm, or shall be framed if solid blocking. When exceeding 1.20 m in height, such walls shall be framed of studs having rhe size required for a!1 additional story. Cripple walls having a stud height exceeding 350 mm shall be braced in accordance with Table 6.26. Solid blocking or wood structural panel sheathing may be used to brace cripple walls havin g a stud height of 350 mm or less. In Seismi c Zone 4, Method 7 is not permitted for bracing any cripple wall stud s. Spac ing of boundary nailing [or requ ired wall bracing shall n OI exceed 150 111m on cenler along the foundation plate and the top plate of the cripple wall. Nail size. nail spacing for fi eld nailing and morc restricti ve boundary nailing requirements shall be as requi red elsewhere in the code for the speci fi c brac ing material used.
620.10.6 Headers Headers and lintels shall conform to the requirements set forth in thi s paragraph and together with their supporting systems shall be designed to support the loads specified in this code. All openings 1200 mm wide or less in bearin g wa1l5 shall be provided with headers consisting of either two pieces of 50 mIll framing lumber placed on edge and securely fa stened together or 100 mm lumber of equival ent cross secti on. All openings more than 1.20 m. wide shall be provided with headers or lintels. Each end of lintel or hc.ader shall have a length of bearing of not less than 38 nun for the full width of the lint el. 620.10,7 Pipes in Walls Stud partitions containin g plumbing, heating, or other pipes shall be so framed and the joists underneath so spaced as to give proper clearance for the piping. Where a partition conlaining such piping runs parallel to the floor joists, the
620.10.9 Cutting and Notching In exteri or walls and bearing partitions, any wood stud ma y be cut or notched to a depth not exceedin g 25 percent of its width. Cutting or notching of stud s to a depth not greater than 40 percent of the width of th e stu d is pcnnitted in nonbearing partitions supp0l1ing no loads other than the weight of the partition. 620.10.10 Bored Holes Bored holes may be peonitted in any wood stud provided th e holcs arc not greater than 40 percent of the stud width . Bored holes not greater th an 60 percent of th e wid th of lhe stud y is permilted in Ilonbea ring partitions or in any wall where each bored stud is doubled, provided not more than two such successive dou bled st ud s arc so bored. III no case shall the edge of the bored hole be nearer than 16 to the edge of the stud . Bored holes shall lIot be located at the same section of stud as a cut or notch.
11m}
620.10,11 Roof and Ceiling Framing 620.10.11,1 General The framing details required in thi s secti on apply to roofs having a minimum slope of 3 units vertical in 12 units hori zo ntal (25% slope) or greater. Wh en the roof slope is less than 3 units vertical in 12 units hori zon tal (25% slope), members supporti ng rancrs and ceiling joisls such as ridge boa rd, hips and vall eys shall be des igned ~IS beam s. 620.10.11.2 Framing Raft ers shall be framed directl y opposite each other at Ihe rid ge. There shall be a ridge board at least 25 mill nominal thi ckness at all ridges and not less in depth than the cut end of the rafter. At all valleys and hips there shall be a single valley or hip rafter not less than 50 mIll nomin al thickness and not less than the Ctlt of the raft er.
National Siructural Code of th e Philippines 6'" Edition Volume 1
.~
620.10.11.3 Notches and Holes Not c hin g at the e nds of nlficfs or ceiling joists sh all not
exceed olle fourth th e depth. Notches ill (he top or bottom of the rafler or ceiling joist shall nOI exceed one sixth the depth and shalt not be located in the middle one third of the span , excepl (iHI! a not ch not exceeding one third of the depth is permitted in the top of the raft er or ceili ng joist 11m fUl1hcr from the face of the SUppOI1 than the deplh of the
member. Holes bored in rafters Or ceiling joists shall not be within 50 mill of the top and bottom and their diameter shall not exceed one third the depth of the member.
620.10.11.4 Framing Around Openings Trimmer and header rafters shall he doubled. or of lumber
620.10.11.9 Roof Planking Pl allk ing shall be de signed in accordance with the gencr:d pro visions or thi s code. In lieu of ~uc h design, 50 mill lOnguc-:'lJlll-groovc planking lila), bc uSI..'d in accordance wit h Table 6.22. Joints in slIe i l planking Illay be randomly spaced. provided the system is applied to not less th an three COl1linliOLlS spans, the plank s lire ce nter· matched and end-matched o ::~ plined , cach pla nk bears on at least one SUppOI1, and the j0lll\.S arc separated by at least 600 mm in adjacent pieces.
620.10.11.10 Exit Facilities In Seismic Zone 4. exterior ex it balconies, stairs and simib r exi t facilities shall be 'lOchored 10 the primary st mcture
of equivalent cross section, when the span of the hcad(:r
forces. Such attachment shall not be acco mpli shed by
exceeds 1.20
of toe nails or nails subject to withdrawal.
The ends of header rafters more than 1.80 m l ong shaH be supported by framing anchors or rafter hangers unless bearing on a beam. pa!1ition or wa ll. Ill ,
·'ii'.:,::.,'.:" .,,·; .
.
620.10.11.5 Raner Ties Rafter shall be nailed to adjacent ceiling joi sts (0 form a con tinuou s tic between exterior wa lls when such j oists are paralic I to the rafters. Where not parallel, rafter. shall be ti ed to 25 mm by 100 Illlll (nominal) minimum-size crossties. Rafter ties shall be spaced l10t more than 1.20 III un ·center. 620.10.11.6 Purlins The maximum span of 5011)111 by 150 111m purJins shall be 1.80 m but in no case shall the purlins be smaller than 50 mm by 100 mm members. The unbraced length of strut s shall not exceed 2.40 m and the minimum slope of the struts shall be 45 degrees from the horizontal. 620.10.11.7 Blocking Roof rafters and ceiling joists shall be suppor1ed laterally to prevent rotation and lateral displacement When required by Section 616. Roof trusses shall be supported laterall y at points of beari ng by solid blocking or by other equivalent means to prevent rotarion and lateral displacement.
620.10.11.8 Roof Sheathing Roof sheathing shall be in accordance with Tables 6, I 0 and 6.11 for wood structural panels, and Table 6.9 for lumber. Joints in lumber sheathing shall occur over support unless approved end-matched is used, in which case each piece shall bear on at least tw o supports. Wood structural panels used for roof sheathing shall be bonded by intermediate or exterior gille. Wood structural panel roof sheathing exposed on the underside shall be bo nded with exterior glue.
lI s(,~:i
,·,..:.'~ ~W .H.;; ,·
"~~ .~~~ .. ~ :. !,~, :,;..~~.~ ~;}. ,:.1:1;,,:, ;:;" .~;'.!': ~!r?( . · C@NNE(]!~Eni;w(j)'(;)D .. ;::.:;.
;·.:~"';if\~";·".
621.1 Design and Faurication The desi gn and fabri cation of metal plate connected wood tmsscs shall be in accordance with ANS IrfPI 1· 199:;, National Design Standard for Metal Plate Connected Wood Truss Construction of the Truss Plate Institute. 621.2 Performance FuJI-scale load tests in accordance with ANSlfTPJ 2 may be required at the option of the building official to provide a means of demonstrating that minimum adequai e performance is obtainable from specific metal plate connector plates. various lumber types and grades. it particular truss desi gn and a particular fabricatiot! procedure. ANSlffPI 2 provides procedures for testing an d evaluating wood tl1JsseS designed ill accordance wit h ANSlffPI I. 621.3 In-Plant Inspection Each truss manu facturer shall ret ain an approved agcnr ,' ha ving no financial interest ill the plant being inspcc(c.: make nonscheduled inspections shall cover all phases of the truss operat ion, in cl ud ing lumber sto rage, handling, cu ttin g, fixtures, presses or rollers, fabrication bundling and ba ndi ng, handling,
Association of Structural Engineers of the Philippines
CHAPTEH G · \'Voo<1
J.
Identity of the company m
2.
The design load .
3.
The spacing of trusses.
(j·35
622.1 General In cases where the identification of a particular wood species is 110t known. thereforc-,working stresscs CtUlilOl be found in Table 6.1, machine grad~d lumber can be lIsed for general and structural applications.
!
I
I
622.2 Design Properties for Machine Graded Lumber The design propcrlics for mach ine grn<.led lumber developed by the Forest Products Research and Development Institute arc shown ill Table 6.31 - 6.34 . These propenies .Ire appli ca ble for dry lumber (moislure content :S 16%) only. In green lumber (moisture content ?:: 28%) , the design strength shall be reduced by 40% and Illodulus of elasticity by 20% For lumber with moisture content between 16% and 28%, the dcsign properties may be obtaincd by direct intclpolation. 622.3 Design Using Machine Graded Lumber The bas ic work ing va lues given in Secti on 622.2 may be llsed to de sign timber structures in accordance with th e
rul es given by NSCP and other appropriate national and/or international standards.
622.4 Preservative Treatment To ensure the durability of MGL against bio-deteriorating agent s such as fun gi and insects, MGL should be treated wit h an ellvironment -friendly prescfv,l{ive.
622.5 Moisture Content A given piece of lumber is considered dry, partially seasoned, and green, when their respective moisture contents is above 10%, 22% - 28%. and greate r than 28% . 622.6 Markings Prior to usc, each machine graded lumber should be inspec ted for a mark that co ntains the mill in which the lumber was graded, organi7..atioll that eellifies the quality of the grading procedure, timber size, stress grade and moi sture content.
National Siruciural Code of 1i1O Philippines 6'h Edilion Volume 1
G':lG
CHAPTEr! G . Wood
Table 6.1 - Working Stresses for Visually Stress-Graded Unseasoned Structural Timber of I)hilippine Woods " ..
Specie'S (Com ilion and not .'H1ieal Nmncs) ~~.-
....------ . - ---.-
( 1)
I.
..
~- - . -- - '-
-..__.._._-"-'" r
80% Stress Grade Compression l)arltll('llo GrHin
Compr('."sion
(3) x IO"
(4)
(5)
._----. (6)
MPa
MPa
MP"
MPa
MP"
263 25 .0 28.7 25.8 24.0 21.8 31.3
8.22
9.36 830 9.63 6. 54 8.33 9.72
14.5 15.6 15.8 16.0 15.4 13. 7 21.60
5.91 4.3 1 8.70 6.03 6.34 4.97 10.2
2. 95 2.64 3.02 2.78 2.8 8 2.6 1 3.38
24.5
9.78
15.8
6.27
2.49
18.6 18.9 18.1 16.2 20.8 21.8 20.9 19.0
5.35 6.57 6. 36 5A 3 6.84 8.47 7.20 7.56
10.8 I 1.4 11.3 9.44 13.5 13.2 I 1.7 11.2
3.90 3.27 3.4 1 2.27 3.52 4.26 4.39 3.95
2.06 2.24 2. 18 1.92 2.3 6 2.40 2.47 2.35
18.8 18.4 19.8 16.5
6.82 8.04 7.9 2 4. 66
11.9 10.6 11 .8 10.5
4 .84 3.46 ).98 3.83
2.29 1.96 2. 18 2.7 1
20.5 18.9
6.72 6.66
11 .4 11.1 2
3.70 2.32
2.40 2. 14
18.0 16.6
5.94 6.53
11.4 10.0
3.07 2.50
1.91 2.05
16.5 16.6 16.3 14.3 15.0
7.31 6.4 8 6.38 5.3 3 606
9.56 9.89 9.20 8. 16
2.20 2.33 7. .48 1.99 2.02
1.73 1.87. 1.98 1.90 1.8'1
13 .9 13.8 16.8 15.4 15 .7 16.2 13.8 14.7 15.7
5.83 5.41 5.94 6.30 6.50 5.56 5.98 6.66 5.67
8. 18 8.54 9.51 9.33 8.83 9.17 8.38 8.29 8.83
1.72 1.96 2.92
1.48 1.59 1.85
Modulus of Elast icit)' in Bending ..... _--
High Strength Group Agoho (C(Jsuarin
MaJabayabas (Trislania SPIJ.) Manggachapui {Hopea sP!> .) Mojave (Vitcx parviOora Juss.) Narig (Vatica spp.) Sasa lit (Tcijmanniode ndron lIhcrniiinum (Merr) llkh .) Y akal (S hore!! spp.)
II.
Bending lind Tcn."ion j'aritllello Grain (2)
~,".---
Moderately High Strengtl I Group
Ant ipolo (Arlhocarpus spp. )
Binggas (Tcnni na lia spp.) Bokbok (Xanth ophyllum ex ccls um (Bllllne) Miq.J
Dao (D racontomc lon spp.) Gat.lsan (Garci ni a vcnulosa (Blanco) Choisy ) Gu ijo (S horea spp.) Kamagong (Diospyros spp. ) Kamatog {Erythrophloeum dcnsiOorum (Elm) Merr.) Kalmon (Dillcn ia spp) Kata (Amoora spp.) LOJll
Mahogany, Big-leafed (Swi etcnia macrophylla King)
Makaasim (Sysyg iulIl nitidt1111 BCllIh) Malaka uayan [D ec Lisocarpll s philippiIleIlsi~ (Foxw.) de u llIb.) Naml (Pterocarpu s indicus Willd) Pahu(an (Mangi fera spp.)
III
Medium Strength Group Apitong (Diptcrocarplis sPP .) Bagtikan [Parashorea malaa nonan (Blanco) MeIT_) DangkaJan (Ca lophyllum sp p.) Gi sa u (Canariul11 spp.) Lanutiln-bagyo fGol1ysly lu s ma crophyllllm (miq.) A iry ShilW] Lau
Malaanonang (Shorca spp.) Malasag ing (A gJa ia spp.) Malugai (Polllctia sp p) Miau (Dysox)'lulll spp.) Nato (Palaquiu m spp.) Palosapis (Ani soptcra spp.) Pine (Pinus spp.) Salaki n (A hanamixis s 1 1.)
-
Association of Structural Engineers of the Philippines
8.96
Sh('ur I'arallello
P'pcndicul;u-
to Grain
Grain
:1 .0"1
2.01
2.78 2.33 2.7:1 1.88
2J)(, 1.98 I ,(i ~~
i
p'I ___L ',..
()·3i"
CH APTEH G · Vv ood
.
__..-
Species
nClldin~ alld
(Commun and Botanical Names)
l'a rnUcI til
T('n.~i()11
(;rlliu
(2)
IV
__
_
.
...•.•....._.... _..
Modulus of Elaslidl)' in Iltonding
COlllprl'ssio n Parallel lu
Comprc)oosioll
Sh~ar
I"pendicular
l'arall el (0
Graill
III Gra in
-_.._--
(3)
(4)
(5)
(6)
X
Vidal lalluta!) [Hibiscus campylo.sipiloll l\m:1.. var. glabrcccns (Har. Ex. Perk.) 1
.---
80% Stress Grade • .....-~~
-.-,-;---.------ .--~
G"aiu
to'
MPa
MPa
MPa
MPa
Ml'a
19.5
5.83
8.54
2.65
2.39
5.47 4.75 4. 13 5.36 2,75 4.09
6.27 733 6.85 7.46 7.23 7,87
1.44 1.30 2.00 1.97 3.32 3.40
1.4 7 1.20 1.66 1.44 2 ,07 1.96
:' .>
Moderately Low S(rengtl~ Group A Inmciga rAg'lIhis dtlHlIllar
11.8 12.6 13.2 12.8 11.9 12.6
._- -
--,--,-- - -- - -- -- - -
---.•
. - ---
63% Stress G rade
E1aslicity III Bcnding
COlllprcs."ion "a ra llel Til Gr:lin
Compression I" pcudicul ar To Grain
S hc:lr f'ar.lll ci To Gr
MPa
x I O~ MPa
MPa
MPa
MPa
20.7 19.7 22.6 20.3 18.9 17.2 24.7
6.47 7.37 6,53 7.58 5. 15 6.5 6 7,65
11.4 12.3 12.5 12.6 12. 1 10 8 17,0
4,65 3.39 6.85 4.75 5,00 3,92 8.07
2,3 2 2,08 2,38 2, 19 2,27 2,06 2,67
19.3
7.70
12,0
4,94
1.96
14,7
4,21
14.9
5,17 5,01 4,28 5,39 6.67 5,67 5.95
8.53 8,98
3,07 2.57
8,90
2.68 1.79
8,79
1.62 1.77 1.72 LSI 1.86 1.89 1.95 1.85
Hendin g And Tens iOIl Pan-lllc1to
S peci es (COIllJllOIl and Bo(anical NUlllcs)
Modulus Of
(1)
I.
Hig h Strength Group Agoho (Casuarina equisclifoli a r orsl) Liusin (Parinari corymbosa (Bl ume) Miq.J Malabayabas (Tri slilnia spp.) Manggaehapui (Hopea spp.)
Molave (Vitex parvinora Juss.) Narig (Vatica srp .) Sasal it [Tcijmanniodcnciron ailernianlllll
(Men")
Bkh. ] Yakal (Sho re. spp,)
JI.
Moderately High Strength Group Antipolo (A rthoearpus spp.) Binggas (Terminali a spp.) Bokbok (Xanlhophyllum CXCCISllll1 (Blumc) Miq.J Dao (Draconlomcion spp.)
Gatasan {Garcinia venulosa (Bl anco) Choisyj Guijo (Shorea spp.) Kamagong (D iospyros spp.) Kum310g IErythrophlocuJll Merf.] Kalmon (Di llcnia spp)
densiflorum
(Elm)
Kata (Amoora spp.) Lomarau (Swintonia fox worlhyi Elm.) Mahogany, Big-leafed (Swintonia mClcrophylla King) Makaasim (Sysyg iul1l nilidul1l Bcnlh) Malakauayan (Dccusocarpus philippinensis (Foxw.) de Laub,] )_ _ _ Narra (Ptcrocarpu s indicus Wi !l",dL
14.3
12,8 16.4 17. 1 16.6 15,()
7.43
10.6 10 .4
9.2 1
1.80 !.54 1.71 2,13
8,95
3.81 2.n 2.34 3'o! 2,92
8 ,79
1.83
1.69
5.37
6,:n
9.38
14.5
15.6 13.0
6. 24 3,67
8.34 9.30 8,24
16.1
5.29
14 ,9
5.24
14.8
2,77 3.35 3.46 3,1 )
National Structural Code of the Philippines 6'" l"ditiOIl Volu me 1
1.89
...
_----
.•
-- -~ -- - - ---- -.- ----.-- . - --~- --- -- -- ---.--
(Common
~'nd
Hobluica l Nanlt.'s)
-_..__._._-- ---_._._.._-;-::-- ---
__
.._
_ _ _____
(_1>-._
Teu.~ j oll
j\-iodulus or ElllstkH)' In
l'ur.tJlello
Bcuditll,\
Bellding And
Spcdcs
- -_..._.- ._--- .
63% Stress Grad(,'
---
C()l1lpJ"(~ ssion
" ' pcndicu.hl .. To (;rll ill
- - ---
Grllill
____12.L_~ ~-::::~_(!_O
-. _...J1L_. _ ._ (8)---
________ .__ _
Clllnpression !'arullel To Gruiu
..-.-...-- ..
.-
---
-'~~i;~i~, I'urallt'l Ttl G roth
i-==- __ _.l.!.!)_ ..
1 X 10.
III
--MPa 1.6 1
7.53 7.79 7.24 6 .4 3 7.06
1.73 1.84 1.96 1.56 1.59
136 1.43 1.56 1.49 1.45
4 .59 4.26 4.68 4.96 5. 12 4 .38 4 .7 1 5.24 4.47
6.44 6.72 7.49 7.35 6 .96 7 .22 6.60 6.53 6.96
135 1.54 2. 30 2.42 2 . 19 1.84 2.15 1.48 2 .32
1.17 1.25 1.46 1.63 1.62 1.56 1. 33 1.23 1.48
15.4
4 .59
6.73
2.09
1.88
9 .26 9.94 10.4 10.0 9.37 9.90
4 .30 3.74 3.25 4 .22 2. 16 3.22
4.94 5 .78 5.39 5 .8 7 5. 70 6.20
1.1 3 1.03 1.58 1.55 2.61 2.68
1.1 6 0.95 1.31 1.14 1.63 1. 55
Bending and Tension Parallel to Grain _. (12)
Modulus or Elaslicity in Bending
Compression Parallel 10 Grain
Compression ()'pcndicular to Grain
Shea !: I'arallel to Grain
(13)
(14)
(15)
(16)
MP.
MPa
MPa
906 9376 93 90 10.0 9 .60 8.59 13.5
3.69 2.69 5.44 3 .7 7 3.96 3 .11 6.40
1.84 1..65 1.89 1.74
9 .55 .
3.92
MPa
MPa
MPa
13. 1
5. 15
7 .88
ApilOllg (I)iptcrocarpus spr.) Bagtikan IParashorca malaanonan (Blanco) Me IT.J Dangkalan (Calophylluill spp.) Gisau (Canariulll spp.) Lan u ta n ~bagyo fGonys tylus m
13.0 13 .1 12.8 11.2 11 .8
5.76 5 . 10 5 .03 4 .20 4.77
10 .9 10.9 13.3 12.1 12.3 12. 7 10.9 11.6 12 .4
.-
Mcdiuoll Slrcngth Group
Malaanonang (Sh orca spp.) M,\Iasaging (Aglaia spp.) Malugai (romcli !! spp.) MimI (Dysoxy luJl1 srp.) Nato (Palaquiulll srp.) Palosapis (An isoptcra spp.) Pine (Pinu s spp .)
Salakin (Aphanamixis spp. ) V ida l lanu tan lHibi scus camp ylo siphon T mel.. var. gJa brccens (H af. Ex. Perk.) J
IV
MPa 1.97
- _.
Modcl'atcly Low Strength Group Almac iga {Aga thi s dam mara (Lamb.) Rilh .) Bayok (Ptcrospermu m spp.) Lingo-Jingo (Y itcx turczaninowji MelT.) Mangasinoro (Shorca spp.) Raimrec [Sarnanca samail (Jacq.) MelT.} Ycmanc .(Gmclinft arborea R. 13]J__._..... __ _ _
-
.-
J
50% Stress Grade Species (Common and Botanic.. 1 Names) (1)
3
MPa
I.
High Strength Group Agobo (Casuarin a cquiselifoli
Malabayabas (Trisl
.-
ahernianulll
(M en")
16.4 15.6 17 .9 16 . 1 15 .0 13.6 19.6
xlO MPa 5. 14 5.85 5. 19 6.02 4.09 5.20
6.08
15.3 __ , -. 3. 11
Association of Structural Engineers of the Philippines
I.BO 1.63 2.12
--
~J
CHAP TEn G· Wood
639
- --. - --------_._._..Specics (Common ,Hid Botanical Names) -
(I )
II.
Puhutan (Mangilera spp.)
Shcllr Parallel to Grain
--
(14)
(15)
(16)
MP"
(13) x 10' MP"
MP"
MPa
MP"
11.6 I 1.8 I 1.3 10. 1 13.0 13 .6 13. 1 11.9
3.34 4.11 3.97 3.39 4.27 5.30 4.50 4. 72
6.77 7.13 7.06 5.90 8.42 8.22 7.31 6.98
2.44 2.04 2.13 1.42 2.20 2.66 2.74 2.47
11.7 I 1.5 12.4 10.3
4.26
5.02 4.95 2.9 1
7.44 6.62 7.38 6.54
3.03 2.17 2.86 2.39
1.43 1.23 1.36 1.69
12.8 11.8
4.20 4.16
7.10 6.98
2.31 1.45
1.50 1.34
11.2 10.4
3.71 4.08
7.12 6.25
1.92 ' 1.56
1.20 1.28
103 10.4 102 8.93 9.39
4.57 4.05 . 3.99 3.33 3.79
5.97 6.18 5.75 5.10 560
1.37 1.46 1.55 1.24 1.26
1.08 1.14 1.24 1.1 8 I. 15
8.68 8.63 10.5 9.62 9.80 IO.I 8.65 9.19 9.83
3.64 3.38 3.71 3.94 4.06 3.48 3.73 4.1 6 3.54
5. 1 I 5.34 5.95 5.83 5.52 5.73 5.24 5.18 5.52
1.07 1.23 1.83 1.92 1.74 1.46 1.70 1.18 1.84
0.93 0.99 1.16 1.30 1.29 1.24 1.05 0.98 1.18
12.2
3.64
5.34
1.66
1.50
7.35 7.89 8.27 7.98 7.43 7.86
3.4 2 2.97 2.58 3.35 1.72 2.55
3.92 4.58 4.28 4.66 4.52 4.92
0.90 0.8 1 1.25 1.23 2.07 2. 13
0.92 0.75 1.04 0.90 1.30 1.23
,
1.29 1.40 1.36 1.20 1.47 1.50 1.54 1.47
Medium Strength Group
Api long Diptcrocarpus spp.) Baglikan [Parashorea maiaano nan (Blanco) Mer r.] Dangkalan (Calophylilllll spp.) Gisau (Canarium spp.) Lanulan-bagyo fGonyslylus macrophyllum (miq.) Airy Shaw] Lauan (Shorca spp.) Malaanonang (Shorea spp. ) Malasaging (Aglai a spp.) Malugai (Pometia spp.) Miau (Dysox ylum spp.) Nato (Palaquiulll spp.) Palosapis (Anisoptera spp.) Pine (Pinu s spp.) Salakin (Aphanamixis spp.) Vidal lanutan IHibi scus campylosipholl Tu rez., var. glabrccclls (Har. Ex. Perk ,) ] IV
50% Stress Grade Coml'rcS$lon Modulu,,, or Comprcs..'iion P'pcndicular I'arallcl to Elasticity In 10 Grain Gn.in 8cndill~
Moderatcly"High Strcngth GrouJl
Antipolo (Arthoclirpus spp.) Binggas (Tcrminl1lia spp.) Bokbok (Xanthophyllulll CXCclSUIll (B lume) Mi q.] Dao (DracontolllcJoll spp.) Gafi.ISan IGarcinia vcnulosa (Blanco) Choisy] Ouijo (Shorea spp.) Kamagong (Diospyros spp.) Kamatog IErythrophloculll densifIonlfll Elm) Men.] Katmon (Dillcnia srp) Kato (Amoora spp,) L.oll1arau (Swilltonia foxworthyi Elm,) Mahogany. Big-leafed (Swinlonia macropJ,ylJa King) Makaasirn (Sysygiulll nitidurn Bellth) Malakauayan IDcclIsoc,uvus philippinensis (Fo xw .) de Laub.] Nana (Ptcrocarpll:-l indicU:-l Wind)
III
Bcnding and Tcm;ion Parallel to Grain '(12)
.
Moderately Low Strength Group
Almaciga /Agatbis dammara (Lamb.) Rilh .] Bayok (Plel'OSpCnnUlll spp.) Lingo-lingo (Vilcx turczaninowji Merr.)
M
National Siruciural Code ollhe Philippines G'" EdiJion Volume 1
G·tH)
CHI\Pl Ul
(j
Wood
Tllblr 6.2 - Grouping of Spcc.:it's for Determining AlI()w~d)I<.· LfHld . . for Timher Joints ~-.--- -.-.--
..
Spcdcs
::=:::..
I --- ~.
Relativc __ ..~cnsi!'y
(2)- - (iL.~~=-. _ . _
II
Spcdcs (3) . ~.----.-.-
~-.--.--
._._- - _._----_._----_..III _-_.. -- ---_....
Rchltivc __ Dcnsitl_ (4) --~ . -
..-
Sp('('ies
--_. _-_._- _.
-~.~-
Itclnti\'c ~~t.L 1
--'--'--iV--- ' - -Species
--- ---_.-
_____..._. ______..
--. __.-.JQ.L....... ..
RdHti VC Dcnsity ._
_ .J:!l...._....... .... J~)
Mlllabayabas
0.90
Makaasim
0.74
Malugai
0.61
Lingo·lingo
0.48
Sasalit
;).90
Kama gong
(J.72
DangakalHn
0.58
R.]ilHreC
0.48
Agoho
0.84
Guijo
il .70
Api(ong
0.57
Bayok
0.44
Liu sin
0 .79
Binggas
0 .70
Salakin
0 .56
Allllac iga
0.42
Yakal
0.76
K a llllOIl
0 .68
Pinc
0.55
Manggasi noro
0.42
Narig
0.72
GalaS
0 .67
Lanulan-bagyo
053
YC Il)(l l) C
0.42
Manggachapui
0.71
Bok-bok
0.64
Mi,lU
0.52
Mo lave
0.69
KalT1<1tog
0.64
Pal(Jsapis
0.52
Lomarau
0.64
Malllsaging
0.5 I
Kal a
0.59
Vidal Lanutan
0.50
Pahutan
0.55
Gisau
0.50
Mahogany. big
0.54
Nato
0.49
A ntipo lo
0.52
Bagtikan
0.44
NaITI:l
0.52
MalmUlonang
0.41
Malakauayan
0.50
Lauan
Dao
0.48
,
Icaf
a See Table 6.35 for Working Stresses for Other Visually Stre ss-Graded Unseasoned Structural Timber of Philippine Woods. SOURCE: Philippine Timber Design Standards (1. E Rocafort and J. O. Siopongco) November, 1991 (FPRDI Temlinal Report)
Association of Siructura l Engineers of the Philippines
CHM' lTH
(~Wood
i;(~
1
Tahle 6.3 - Nailing Schedule I. 2.
3. ·1 .
7.
nail 50 mm sub r!ool' (0 joist or girder, 'blind and face nail Sole pJa[(~ 10 joist or blocking. typical face nail So le picHe ,10 joist or blocking, at braced wall panels Top plat e 10 slud , end nail
8.
$lU d 10 sole plale
9. 10.
Double studs, fa ce nail Doubled lOp plates, typic.tl face nail Double lOp rim es. Iilp splice Blocking between joists or nlftcrs to top rlate, {oenail
o. 6.
i
I, !
I II
I
I;
Co nlwt'lioll Joist 10 sill Of I~ jnkr. toco;jij iJridginl::! 10 jois t. [oena il c,le h end 25 III x I SO Jllill su bflooJ' or less!{) each joist, far e nail Wider than 25 IlUli x 150 mill slIhnoor 10 cach juist. f~lcc
I I.
12. 11 14. 15. 16. 17. 18. 19. 20 21
Rimjoisl to top plate, toenail Top phll cs. laps and intersections, f
__ ...~. __
1-65Jll!ll 2-651l1ll1 2-6SIllIll 3-65mlll
Na!!~l1g-~~__~'~='==
2-901ll1ll 90mJll al 400 Illlll O.C . 3-90mlll pcr 400 IllIJl
2-90111111 4-65mm, toenail or 2-90mlll. end nail 90mm at 600 mm D.C. 90mm at 400 111111 O.C. 8~90m lll
3-65mm 65111111 at 150 111m o.c. 2-9001m
90mm at 400 mill
O.C.
along each cdgc
3-65m!ll 4-6511)11)
3-901ll1ll
RaJkr 10 plale, toenail
3-90mm 3-65n1l11
25 mm brace to each stud and plate , face nair 25 Illlll x 200 mill sheathing or less (0 each bearin g, face
2-65mm
2~65mm
nail
22 23 24 25. 26.
Wider than 25 nun x 200 lnm shcmhing to cach bC<1ring, face nai l Buill-Up comer studs 13l1ilt-up gird er Hnd beams
50 mill planks Wood structural panels and particleboard 2; Subnoor and wall sheilthing (to framin g): 12 I11Ill
28
Illlll -
32 mill
Combination subfloor-underJayment (10 framing): 20 mm and less
25 mill 30111111 - 32 mill Panel siding (to framing/ 12 mill or less 16 mill 22
27.
Illlll -
3-65rnl11
90mlll at 600 Illlll O.C . lOOmm at 800 ml11 D.C. at lOp and bottom and siaggered 2- 1OOmn) <'It ends and at each spli ce 2-90mm al each bearing 50mm ) 65Jl11ll ~ or SOHlIn
.I
65mm .! 75 mlll J or 65111111
5
SOmm S 6501m .~ 75m!Jl
4
50mJll
6
or 65mm
.1
.. 651l11ll _'_ _... ___ ~ ___~. __ _~ _________ .__________
th
National Structura l Code of the Philippines 6 Edition VO!Ull1C 1
6 -42
CHAP TEH 6 - Wood
-. - ~ --
...-
Table 6.3 - Nailing Schedule (Col\('d) ~~ -
..
Ts~bcrboard sheathing 7: 12 111m
---_._-
- -.----.- .-- - -.-~~~ . -
Nailing
-- - --.--. --
I
IOmnl x 40111Jll s 50mm-l
IOmm x 30111111 y lOlllm x 40rnm II
20mm
65 mm
J
IOJr.m x 30mm \I
29_
Inlerior panelin g
40mm
6 nUll JOmm
JO
50nlln~ _ ____ ___ ~ _______ ~
-
-
- - -----------
Nares Fol' Table 6.3 I
Com mon o r box nails may be u.~ed i!XCCP' where otherwise sWlcd.
} Nails sluIced af 150 m/1l 01/ ("(/liN 01 edge:;, 300 111m at illlemJcc/ialc SIIPI'lHl.\' e:lTCpl 150 IIlIIlllI (Ill sfll'porl s where .f/milS afe 1200 111111 01"
more. For ,wilillg a/wood Slrucfu r(J.1 panel and pa r(icle/JoCJrd diaphragms (ll1d sllf'(//' wol/s. (('fl.'" /0 Secfiolls 6 /4.3.3 (I/ld 6 14.4. Nails f or 11'011 J
sheathing ma), be ('ommon, box or casing. ComlllOIl or deformed shank. Camlllol/.
Dejonm:d shank. Corro.riofl-rcsiS/(1Il1 Siding or {'(Ising flails cQIl/arming /0 Ihe rel/llirelllt'nlS o/S(,£"Iioli 603.3,
75 111111 on ("Cllft'r at e,ncrior edgt.'i anA 150 mlf! on cemer Of h!/('rmediOf(' l'IIf'POrfS. Corrosion-resiswn/ roofing nails wilh 10 111m head (lnd 40 mm lell8th for J2 mill .rheathing and 45 mm fen grll filr 20
1 Faslener.l" s/1{Iced
~
1111/1
s!II:(}/hiIl8
con/onnin8 to 'h e f('q uiremCIIIJ o[Sectioll 603. 3.
~ CorrosiOfl'resisfatl' staples wilh 1I0mil/a i 10 mill croW/I 30 mill length for 12 /11111 sheathillg alld 40 11/111 iI'1I8111 f or 20 11/11/ s/telllltillg cOll/omlitlg to th e requirements o[Sectioll 603.3. 10 Pan('/ supports at 400 mill (500 mm if sire/18th axi.\' in the lont: direc tion of th e pa lle!. ullloJ othawi,\"(.' marked). C/lsing or/ill ish lIail.~ spaced 150 IIIITI on palle! edges, 300 11111/ at i'l/ermediale supports. II
P(lfleJ SIIP/wrtS 01600 trim, Casillg Qr finish ,wi/of spa('Cd 150 111m all paneJ edges. 300 mill aI illlenlt('diatl' SIl/'I.'!)rt.f.
Association of Structural Engineers of the Philippines
CHAr'TEf, G - Wood
6-43
Table 6.4 - Wood Structural Panel Roof Sheathing Nailing Schedule ---------- ---------~ROOF FASTENING ZONifT-- --WIND REGION
_.~~==~~.-]=~==}____===T==_====3=_==
PANEL LOCATION
NAILS
Fastening Schedule
_________. __.___. __~m on ccnter)
Greater thall J 45
_~..__.Jcj,!l
-~c----j---~-------
Greater than ! 29
~kjlh to
145 k h
129 kph or less I
6Smlll common
65mmcomillon 65mm common
--'-P-"a~nc'_"I__'c"dli'c""s'__-_
__+----.J.2
Panel Field __ Panel cdgc2.· Panel Fi('.ld -Pa!lclcdg~ Panel Field
'~------.-----,----
Applies ollly to 1I1('WI r()(~r heighl.I' lip 10 10.5
ilL
__. .J..5Q
----100-,----ISO ' ---.-
-_._---- ISO
100 150 150 300
150 150
ISO
300
For melll! roof heights oW'r 10.0 m., Ihe !wiling ~'h(/II be designed.
TIl(' mo/fiHtelling WIIl'.I" Ill"(' shown below:
1.20 rn
110m - .
+-
--..
... _
I.:!()m
-*-1 ,,"it) III (INCLUDING O"I(j
1------1- 1 - - - - - 1 1 1
1 1 1
1
1
1
1
:C)
1 1 1 1 1 1 1
1
1
1
1
1 1 1 1 1
m V
1 1
2
1 1
ROOF RlDGE
Roof Fastening Zones Edge spacing also applies Ol'er roofframing •
Use 65111111 ring-shank nails ill fhis wne
at
if mean
gable-end wa/,'s. rooflleight is greater than 7.50 III
th
National Structural Code of the Philippines 6 Edition Volume 1
Ill.
OVERHANG)
""" 6~44
r----.
CHAPTER 6 ~ Wood
~ ______________---,,'Ir-'able
6.5 - Exposed
I~ywood
Panel Sidin Stud Sp:lcing Plywood Siding Applied Directly to Studs or Over Sheathing
Minimum Thickness]
Minimum Number of Plies
10 111m
3
400 2
12 111m
4
600
•• n .
I
?
_
. . ~~. _ _ _ • • • _ _ •
_.~
_ _ _ _ _ _. _
1Jllckness of gram'cd ponds /.1" measured (/( bO/f()111 of grool'('S. May he 600 111111 If plywood siding applied with face grain fN.'rpelldirular 10 SlUffs or ()I'('T olle of fhe following' (/) 25 min board sheathing, (2) 10 mm wood sfl"ucfllml pm!!'! sheathing or (3) 10 mill wood Slm({lIral pallet shcO/hing willi .l'Irl'n[.:111 axis (which i.r rhe long direction oflhe pm!l!1 unless otlwnl'ise marked) ofs/U'alhing pc/pendiCIIla!" {(J slut/s,
Table 6.6 - Wood Shingle and Shake Side Wall Exposures Shin1!lc or Shake _.
__.
Length and Type 400 mm shingles 450mm shingles ~_2QO nun shingles .___ . . _-----450 nun rcsawn shakes 450mm straight-split shakes L_~OO mm rcsawr~._~}"~~~~~ __ ~~_
Maximum Weather Exposures (mm) DOllbl('~Coursi n Single-Coursing
No.2 No.1 180 180 " 210 210 ----290 290 . -- - - - - - ------_. 180. _ - - - _ 180
1 - -.300 .. 350 - - 400··------ - _ . No~
~----
~-----.
290
...." ...
---_._--
__
350 _...-
~
-"-
'M~'_"~
_- -_.__..--
~--~--
------_ ...
400 -........-.- -... ...SOO
-
-~
-- -~~~
--_._-
-_•...._.
Table 6.7 - Allowable Spans for Exposed Particleboard Panel Siding ,-----------,-----------,
Grade
M~I
M~S
Stud Spacing
Minimum Thickness
Siding
400
f-~M~~~2~'~'E~x~te~r~io-r~G~I-uc~·~'-+-----~6~00~----·----------1~6~I-n-,n----~---
JOmm
10 n-,-n-,---~~----·-I-O-,-n-n-, .~ I
Association of Structural Engineers of the Philippines
G-4~)
CHAPT cn 6 . Wood
--j
Table 6.8 - Hardboard Siding .
Minimal Nominal Thickness
SIDING
(mm)
.,,
IAlP Sidina
I. ..
Direct to SllJd~ Over Sheath in '
~-.-
~~~re ~e
Direct to
I I
__
Framing
(SOIlIJI1 x 100mm) Maximum Spacing _..
~9_"-f 10
____
.~_.400 4(X)
o.c.
Illm O.C .
I I
- - ----I
65 75
I
Stud~
600 nun o.c .
10
600 mlTIo.c.
10
..1:...._§hiplap Edge I'anel Sid~!R. __ - - ---=--- r-Dirccl lo SlUds
10
150 mill O.C. edges; 300 mm o.c. at intermed iate supports 150 nun o.c. edges; 300 mm o.c. at
50
65
intcrrnediatc suppo rts --- - ---
400 mill O.C.
._-_.. .._...._-Over Sheathin g
150 mill o.c. edges; 300 mill o.c. al intcflncd iate supports 150 mm o.c. edges; 300ml11 o.c. at intermediate suppons
50
-10
400 mill o.c. 400 mill O.C .
._-
-_.-
Over Sheathing
,
111111
NAil. SPACING'"-- '' - -''' - GCller:]uraCin g Pallels ,--
(!lUll)
_._-----_. -_._-
Panel Siding
I---
1.-.. --- -- -
N.iI--Size '.' -
400
l1un C.C.
65
1I
Not 8Ep liclI blc___ Not applicable
- - - - - - .---100 ':1lI1
O.C.
intermediate supports
) 00 mm o.c. edges; 200 111m O.C. intermediate SUpp OI1~
-- --100 !llm o.c. edges; 200 mill O.C. inlermediale supports 100 mm o.c. edges; 200 mmo.c. intermediate SUPPOI1S
" wah SectlOlI 6/ 9. Nmls shall be corro.flon reslstan/ III accorda1/ce
1 Minimum acceplabfe nail dim ensions (mm) .
Shank diiln-'-cC"'c·r--- - - - ._.______ !~_~ncl Head diameter J
edges;
200 mm o.c.
When /I.H~d 10 comply wllh
Si~.~~lg (mOl)
-~--
--1----------7'-;;-------- ..-6.0
SeC/lOll
La p Siding 2 .. 5 6.0
(m~;)
-
d
_ _ _
620./0.3.
Table 6.9 - Allowable Spans for Lumber Floor and Roof Sheathing 1.2 Minimum Net Thickness (mOl) of Lumber Placed Span
~_-==:====t~~- 7~ ----~1.
___ ~ __=J_·_.__~~_~~I=-JL_~=
- - ---- -- -- -, -- - ""7~..- -- - ,- -.. - ___ ROOl_S - - L.:.:J'-;--c--:,,6=00---:-..,,--'-c1 ---,,---,:,, 16,--.-::--:--:-:-,1.--- 16 f
----- .--- ..... 16
Instal/a/ion deltll/.f JIm" c:ollfonll (0 SecllOIl 620.8./ (Jnd 620.1 1.7 for floor atlll roof s/watl/mg, 'l'.f/Jee/wel)'.
1 Floor 01" roof silem/Jillg cOI\fo nllillg wilh Ih is fable shall be deemed 10 meet lit e design crilnia oj Sefliofl 620.10.11 . J
MaximUIII 19 pcrcel/ll/loiSfl/,." callfenl.
National Structural Code of the Philippines 6'" Edition Volume 1
-- -
20
6A6
CHAPTEH 6· Wood
Tahle 6.JO ~ Allowable Spans and Loads for Wood Strllctul'HI Panel Sheathing and Single~Flo()r Gradt·s Continuous Over Two or More Spans with Strength Axis P(~rpcndiclllal' to Supports /,? ~I; I,', ~ Grades Floor ' Roor '
Pa;;~':i~~'111 Spl,:,~''''noor 1 {I
1\
Wi th ou' [~dgc ~:,~:lp~;~tg6e ... ..... Support 300 300 400 400 500 . . 500 600 500' 600 600 800 700 1000 800 1200 900 1350 1000 1500 1200
(mm)
J ••
300/0 400/0 50010 60010 600/400 800/400 200/1\(\0
1350/800 150011200
8
8, 9 8, 9 10,12 12 12, 16 16, 20, 22 20, 22 22, 25 22, 25, 30
. Grades
::::~~ ~~l~'~) Span
I
(kN/ m2)
Total Load
Live Load
Maximum Spall (mm)
ti
'.'1.44 1.44 1.44 1.44 1.92 1.44 1.44 1.68 1.68 1.68
1.92 1.92 1.92 1.92 2AO 1.92 1.92 2.16 2.16 2.16
0 0 0
400 400" 500 ' .' 600 SOO
~~'~p~~g6e
Wi~~~~~~~ge
600 SOO 1200 1200 1500
600 800 900 1000 I ZOO
..
l2()(i
Load ~ (kN/n/) Total Load
Li ve Load
2.40 1.92 1.68 2.40
1.92 1.44 1.20 1.92 2.40
2AO
Milx imu m Span ( mm)
400 500. 600 800 12(X)
Applies to f)(lllels 600 mm or Wider.
Floor a",1 roof sllealhillg cOllforming wilh IM.{ lable sha/l be d('cm('d 10 mN t Ille desigll criteria of Sectioll 6. J /. J
Ulli/on" load deflectioll JimilalioflS 1/111(} of Slmll IlIlder lil'e load I)ills d ead load, 1610 under iiI'(' I<)(u/ ol/I)'. Panel edg es sh{/ff have appro ved fOltlill e·and·glOolic joinf.~ or Jlralf be SUf'llOrted Wilh blocking Imle.ts 6 mm lIIill i lllum IhicJ;nes.~ Imdcr/lI),mcn{ o r 40 mm of approw!d cel/ular or ligh/w('igh/ concrete is placed m'e/" Ihe subjloo,., or finish floor is 20 111m wood strip. Allowable IIIIi/onn load based 011 deflection oj/I)U) of span is 4.8 kNlm 2 ('xcep l Ihc span mling oj J200 111m on CCII/C/' is /Jased ( 11/ /I lowl load oj 3. /0 kNlm.
j
Allowa/1fe load (It maximulIl span.
6
Tongul! . and.groo\,e edges, pan'" edge clips
7
on arUNj, lumber blocking, or olher. 0111)' Ilimbe! blocking !ilwll slIli!)j), blocked diapilmgm.f 1"11(jW'l"ellll!lll.r. " -01" /2 111m punel. maxilllum spml shall be 600 mm.
1/
Ma y bl' 600 111111 0/1 eenrer wh<'re ZO 11/111 woad strip flooring is installed at riSlu (mgles to joist.
(01lC
.
Floor
Maximum Span (mm )
P'lliel Thickness
12,16 16,20 20 22 . 28, 30
J
110[)r'
(mill)
400 D.C. 500 D.c. 600 D.C. 8000.c. 1200 D.C.
Load
Maximum Spall (nun)
Pmlcl Thi ckness
midway betwc('1/ ('(l eh support, except
/ W(J
equ(lIf.)' SP(1C('t/ be/w('('n supportS 1200
v Ma)" he 600 mill 0 11 ('ellter forflaol"s where 40 tlUlI (If ccl/ular or lighrweiKhl concrete is Ol1piil'd (II'cr th e panels.
Association of Structura l Engineers of tile Pililippines
Imll
CH f\PT EH G· Woud
G·4!
Table 6.1 1 ~ Allowable Loads for Wood Structural Panel Roof Sheathing Continuous Over Two or More Spans and Strength Axis Parallel to Supports r .___~__ ~~~~~-,(~P~I,IL'" :.:'.::o:::oTd-,sc:·t::ru",c"t",u,-,r:::a,-l,,1":::""n",c",ls"a'T,,,·c,,fic:"v,-e,,-,,p,c:,II'l:',,,,fi,,l;;vc,_'-'.la,,'YL(c'ir,-"u:.: 1l1.~ss otherwise noted) 1. 1 . r---~.-.-Tlli cklless (111111) MaxilllUlll 51)"11 .. ______ ._~~~i! at fv!.~'!!...~.P_~!. U J~_~.pn.l . .-__,. . -._...._. _. Panel Gnuk (mill) l.Ave Iowl ._-- ---s;;:;;-ct;;;;;(I- -"-- " "- ")2" -"'-'--" ~-- '''0:96-'''-''-''''-' ·- --· ..·....····"1"'.4"4'-- -'- -
"--'-'-600--"-'-
12
--'-12
;=....... ___.:=,:", _=+_. . -----------~--
-. 600 . 60IJ
...~ ... ---
1.68
-!'T2"T- ...... -
.
2. 16 .1
..
----2~40'--~·-
~---
600 -. 3.35 ~- --3:8'l----~ ... 4.N 600 4.3 1 .__. Othel' Grades Covered in J2 2.40 400 1.92 --;-;;~;"'::':':;=::~:';;::':':~'::-I---..--;.;::.~--+..·· ~~,-- --+----~~.--t_-__:_;;_;:_-- .. une Standard 23·2 Of' 23-3 12 I. 20 0.96 600 1.20 600 600 1.92 .... 600 2. 16 W 2.87 ' 3. 11 ' 600
W
I
Noo/ shcar/rlllf.: COli/On/tillS WIlIt tJIIS wblt- shall be dl'emed /0 //lCt'l rhr dr.\"I"f.[l1 (Tlleria II/Sec /lOll 6.11 .
U"iformload dejleclioll /im ilatioltJ: 11180 oj 5pWI undl'r li\'(' 10(1(1 pIllS til'lul loa(/. 1124() under liI'I' load ollly. Edge.\" .I·half />e bloc-h'd wilh lumbl'l" or OIlier appn!l'l'd fyp<' 0/ NIgl' supporlJ· For composite alld /tm r·l'iy 1' /YlI"fJod .~/ruCflll"lll ,umrl. Imul shol/ be rCI/II( w il,y 0.72 kNlm'.
Table 6.12 - Allowable Span for Wood Structural Panel Combin
Maximum Spacing of Joists (mm) 400 1200 I 600 I 800 I 500 c_~S~p~e~c~ie~s~G ~,~r~o~u~p_ ' _'I __~~~~~-'~~__~7'~~~r-~T~h~i~c~k~n~es~s,,(~n~'m~)'-____ '__~~~~-r~~~~~~~_1 I 12 16 20 1___ _~2,~3~_~1 _ __~16~_~ _ __ ~20~__ ...~ _ _ _~22~_~_ _~_ _ ~ _ _ _ __ ~~ 4 20 22 25 1200 o.c. Span r.ling' 4000.c. 500 o.C. 6000.c. 800 o.C, Identification
I
L
S,)(lIU Imliled II) mille sllOWII becO/ue of po.t.nbi(' ehecfs of CQflCl"lItrofed food.f. Allowable lilli/un" itJllds ' }(Iud 01/ deft/'CIIOtI of 'IJ6/} of span i.l· 4.8 kNlm·'. ('XCCPI afll)I\'able 101/'11 uniform load for J() "u" wood SlI"Il c tliral pallel.l· OI'er joisfS spaced 1200 mill 011 eellter is 3.1 kNlm ). Panel ttfgCJ shaf/ }'(II'e app/"()\'(!d IOngue-al/d-croO\'e joillis or shaf/ be .wppo("wd Il'it!t block in!;, III1IeSS 6 mm minimulli 'lrickn ess IIndcrlaYlIlcm or 38 mill of apllrmwi cd/Illn r or lightweight com:rett> is ploccd (lI'('f tilt .wbfloor, or fillishflool' is 2011/111 wooff Jlrip.
1 Floor JUme/s conformillg with tlli.~ table ,tholl be deemed fa weer the de.~ig/! criteria ofScctioll 61 1. .1 Applicab le to af! grades of,landed eXlerior-lype plywood. See UlJC Sr(JIuiard 23-2for pl),wood slu'cies groups. Appfica /llt~ 10 IInderlaymem grade WId C-C (plugSrd) plywood. alld single floor grade wood struCluml p(meIJ·.
National Structural Code of tile fJllilippines 6'" E,dition Volume 1
-
~-
Thickness (mill)
-- -
12 16 20
20
----
-
All pallels art' continuous oW'r /11'0 or II/ore spalls. Floor sheathing cO/lforming wilh fhis table slwfl hi' deemed 10 /lweI/he dt's;!?n cri{{'riu oj.';('clio/l 6.1 I. J
J
Uniform defiediol) limira/ion: '1J6() oflhe span Imdcr 4.8 kNII1/ minimuII! food. Edge,\" shafllwl'e ronglw-and-grool'l' joim.\" or shall be xuppor/ed wilh blocking. The /Oil/:UI'-tJlld-gro()\'I' palli'ls arc illstaf/ed lI'ill! rhe IOllg dimension peq)<'lUiitu/ar /0 supports. A finish wearing surj(lce is /() be applied 10 rhe lOp ojfhe p{lIId
-----
Table 6 14 - Maximum Diaphragm Dimension Ratios
~--------==~~===-=-=;="-===-==~~~~~--Hortizontal Diaphragms Vertical Di3phragms I-'-''''-'-'=''''-'''-'''''''-'-'''''-''''---i--'.:::=:==.::.::!=-------Maximum Maximulll Material S[)an~Width Ratios Height-Width Ratios Diagonal sheathing, conventional 3; J I: J .. ~2. Diagonal sheathing, special 1-____..24,,:I'------+--------~=~=E~-=~~-.::·~= 3. Wood structural panels and particleboard, nailed all edges 1______4=.:1'--____ ~._. .~~~-._----_.---._ 4. Wood structural panels and pal1icleboard, blocking omitted at 4: 1 _ _interIn~i
I.
+ ____ .. ___
I
III Seismic Zolle 2, the maximum ratio may b(.' 2: 1.
2 111 Seismic Zolle 2, the maximum ralio may be 3%: J 3
Nor permitted.
Association of Structural Engineers of tile Pllilippines
CHA fYlT f~ 6 . Wood
i
Table 6 IS - Limits of Defect. bl' Grade in Joists and Planks for Seasoned ._____ _ A N~lturHJ I.
3.
Wo~_ d ________
Stress Grade Sln'~s Grade Stress Grade Kit~d of Defect.~ _____________ 80 %_~ ____ ___ __ !i!!~ _______ _.__ ~_~_~_2.!'~&___ ___ _ Dcfcds
Worm holes, average diameter (1ll1lximum allowable size in mm)
:1.
2.
(j· tl9
Individual b. Quantity limitation Slope of Grain (maximum variation in mm from longitudinal axis per 300 nun within middle half of length) Checks and Shakes Sil.C of each check and shake, or if in combination, Ihc sum of a_ thc sizes of all checks and shakes within middle half of depth of thc piece shaJl not exceed:
2
Not pcrllliued No! permiued
Not clustered
6 Not cl ustered
20
25
}2
Ij.j
of thickness
IA of thickness
.1/ "(,
of th ickness
··----.. ···--·---E;~di1enec;:-ati~i;·~··'cf;e-cks~;~I--·- - .. _..- . ' .....---... --.-- .....-.--- -_.-.-_.-- --,---. h.
splits at the middle half of the depth of the piece shall not
'.>11
of thickness
!/4 of thickness
extend a distance greater greater than:
c -- I--:-N-:-a-rr- o-"-'--,- - - - ..· ...... --N~~~~~--'-" Knots (Maximum allowable size of ir;"di-v.,-;d7u--a-l
knOI in mm I)
Nominal width o f face. in mm
I
face on edge of wide face within th e micklle third of length o f piece
-........- - - ---_._._-Nam)w
face on edge of Along center line of wide face
50 6 75 12 100 20 125 25 150 30 ZOO 35 40 250 300 45 50 350 400 50 450 and over 50 The SIze of knots orl the narrow face wuhm rhe mIddle tlilrd of
20 25 30 40 50 55 65 70 75
wide face within the middle third of length of piece
12 20 25 30 45 50 55 65 70 75 75
fllce On edge of Along center line of wide face
wid e face witb in lhc
midd le (hird of
--.-- -
Along ce nter line of wid e face
lengt h of piece
20 25 40 50 60 70 80 90 95 100
38 40 50 40 60 50 75 60 100 80 110 90 125 100 125 100 125 .... IOO ____.--'-----'-' IO,~Oc . ---I----"=-
length may be Ulcreascd proportlOl1mcly lOwards rhe ends of th e piece of twice the size permitted Of! fhe narrow fa ce bUI not to exceed that allowable alol!g the allier fin e of the wide face. The size of kllol,'i 011 the edge of wide face within rhe middle fhird (llengrh may be incrca.'ied pl'Opol"tiollOfe/y toward\' fhe eel/fa of rhe wide face and towards the ends of flU! piece to the size permitted alollg fh e all fer fille of the wide face. 111C sum of the .\'ii:,e:o of 01/ knots ;11 ally 150 mill of lellg," of fhe piece shall 110 1 exceed twice fhe m axi mulII p ermissible size of kllots. Two knots of maximum shall tlO! be allowed itl the same J50111111 of leng th Ofl Otl)' faa . CiIlSla knots and knots ill group shallllot be permilled.
National Structural Code of the Philippines 6'" Edition Volume 1
~
CHAPTEI1 ti - Wood
6 -S0
Table 6.15 ~ Limits of Defects by Grade in Joists and Planks for Seasoned Wood
(;-ra-d;--- St~:;~s G;"lIdc- - - ---st;'t~SS (;';:~ \(I ; --~~~____~____~~~~_t_______~ 80~O~~~_____~ _______~6~3~% 500/. Kind of Dcf<.'c (s
n.
---~-- --~Str"s-' s
Handling, Manufacture or Processing I)efc('fs I, Wall e (maximum tlllowablc size in Illlll) Nominal fact dimension ill nUll
3
12 12
IO(l
3 6
125
6
SO 75
15
12 12 15 15
150
10
15 20
200 250 300
12
22
15 18
25 28
350
20 25 30
45 50
20 25 30 38 45 50 55
2
2
3
width x 100
widt h x 100 2
width x IlX) 3
I skip per 5 m or
I skip per 5 m or
400 450 and ovcr 2.
Torn grain (allowable depth if! 111m)
.).
Skips. ,liiowablc size not to exceed:
surface arc,\ (Widt h mill x length ) Depth mm Quantity
I J
skip per 5 m or
~_. _.~ ._. _ . .~!~~~.·~~~:...L~.I. ~g~_I. ~_._. _ _ _
38
.__._....§.!!2r.!£U.~~~g_~.!. )._.._ .____ .. .._. .__ ......s1!E~r_t~<::E..!.~.!.~R[.I1
Association of Structural Engineers of the Philippines
CHAPTU1 G· Wood
-~-----
,~---.--
---.--~-.-.--
Species Group
.
_
----_.-
Grain, (N) .... _------_ ...
___ S
)e~es Gn~.!!p
Diameter (mill)
24 20 18 16 14 12 10 9 8 7 6
.. _-"._- ._..
..
-~
Gage
LatcI'HI Load in Sidc
Withdrawal Load from Side Grain per 25 mill of Pcnetration of Threaded Portion l (N)
Screw Size
9.5 8.0 7.5 7.0 6.0 5.5 5.0 4.5 4.0 3.8 3.5
II
2695 2315 2130 1940 1750 1565 1375 1280 1185 1095 1000
III
1985 1710 1570 1430 1290 1155 1015 945 875 805 735
.--.-~
1370 1180 1085 985 890 795 700 650 605 555 510
IV
I
II
950 820 750 685 620 550 485 450 420 385 355
31 (X) 2295 1935 1610 1315 1045 810 700 605 510 425
266; 1970 1665 1380 1130 900 695 605 520 440 365
SOURCE: Philippine Timber Design Standards (1. E. Rocafort and J. O. Siopongco) November, 1991 (FPRDI Terminal Report)
National Stl"uctul"ai Code of tile Philippines 6(\' Edition Volume 1
(iC)l
~I
2190 1620 1370 1135 925 740 570 495 425 360 300
IV
1825 1350 1140 945 770 615 475 415 355 300 250
Tahle 6.17· Allowable Loads in kN on One Bolt in Seasoned \Vood Load at Both Ends ( Do u hI(' SI~ e_~1 ~L ~_~~!:~~!~JJ~~_~F~! J~(.~I~_ _._.~~_~_______ . ___... _._...._________ .. ...__ ____ ~.,, ___ _ ___ ,_ _,,,-'_ .. _.. __ ~P_~_~~~~_ Groul~jl!.~.~':'.~· to li~.i--'~K in_Tabl~.§.:.~ ___ ... _.~_ .__._ ..___._.___ _
.... I
Length of
Diameter
Bolt in
of Boll d
Main Member L
Parallel to Grain
(mm) p
... 1
Perpcndicular to
_._.~%~_"
.
· · · + W _ ___ I
Parallel to Grain
Perpendicular to
Parallel to Grain
Pcrpcndicula!' to
... IV
Parallel to Grain
.
--
PcrpcndiM
rular to
____'p_____(_;~-.a~~--_ "~_';?'~ __G_~_liI~__'___,:::-,_+_~~~~~_
(mm) --;;c--i-·······-·--··~1__-,(~I)~-j __ .j.21.__
.......-
(3)
. ._'2.._.. _ :---)6_.__
..- - - ...- - , . . . - - . - - - - . --~-..j-~ccCC"-·-+--;;cc-+~.cc____.I
( 4 ) _ ....J2)___
(6)
(7)
:929-==_0.,,-1 -_~=.:~I3£_.=:=::J~i3-~·552
(9) (10) 2.07 3.26 1.82 ._ 2.30 4.01 2.()2 2.67 S.Q2 2.35 2.77 5.52 2.43 3.01 6.27 2.64 2.59 3.99 2.27 2.88 5.00.~ 2.53 3.34 6.27 2.93 3.46._~~~i.._ 3.76 7.84 3.30 I
- -...J!l)c-
7.08 3.76 4.86 1.98 4.20 8.75 . 4.19 _ _... 6.01 ___ 2.21 5.20 40 20 11.0 4.85 7.55 2.56 6.53._ 22 12.1 5.04 8.30 2.66 . _L~~_ _ . _ _ _ _ ~..._~._. 13.7 5.47 9.43 2.89 8.16 12 8.38 4.70 5.75 2.48 4.98 16 10.8 5.23 7.42 2.76 6.43 13.7 607 9.38 3.20 8.12 50 20 .__.21. ... _...__.. 15.1 . . - . . 6.30· 10.3 3.32 __ =~-8.95~ ____ . 25 -; i}---·· 6.83-·- ---11-.8---- --- 3.61· 10.2
3.36 _468 ---2~i 6.80 .... 8.95 3.59 7.74 3.74 6.29 __ 3.29 I 65 20 17.4 7.89 11.9 ._~ __ ._.10.3 4.34 8.10 -~.84.. 22 19.3 8.19 13.2 4.32 11.4 4.50 8.97 3.96 -·ZU-·--s:88-·--1S.·2--··· 4.69 13.2 .4.89 10.2 4.29' 12 9.35 6.84 6.42 3.61 5.56 3.76 4.79 3.30 16 13.8 7.85 948 4.14 8.2 I 4.32 6.85 3.79 75 20 13.3 .._.•. 4.81 11.5 5.01 9.22 4.40 - -19.4 ------- -_..•9.10 . -----_._ _.~ __ ._fl:2..... ~_ 9.45 15.0.__ 4.99___... 13.0 5.20 10.2 4.56 75 255 10.2 17.5 5.41 152 5.64 IIY 4.95 12 9.4~ 7.14 645 3.77 5.59 3.93 4.84 .. ~~ 16 14.1 8.37 9.66 4.42 8.36 4.61 7.09 4.05 80 ~_ 20_.__ ~2.9:l···9.7 1-::: ::=- I 4c9:=== I 3=:=- :=:- I 2L_ _ .2~ =_977 4.69 22 22.9 ___ ~.~~_ 15.7 _. 5.32 13.6 5.54 10.9 4.87 25 26.9 10.9 184 5.77 16.0 6.01 12.5 5.28 12 9.39 7.42 6~44--- -·· 3.92 5.58 4.08 4.84 3.59 16 .--i4J.... - ··9":20 9.79 4.86 848 5.06 7.28 4.45 90 _ .._.1.2...___ 21.3 10.9 14.6 5.77 12.7 6.04 10.5 5.28 22 24.9 11.3 17.1 5.98 14.8 6.24 12.0 548__ 25 294 12.3 20.2 6.49 17.5 6.77 13.9 5.94 _ll.... ____9.40_._ :-··7.40-· --6A~'i.--.-~. 5.58 4.07 4.84 3.58 100 16 14.2 9.84 9.78 5.19 -8.4"7-- 541 .. : ··-f34.___ .-±l_6_. 2 o j i - : i l : = ·.. J2,I__ . __15.1....... __.._. !l.:il.. __ .__ 13J..._. ....._ ...!l.(",~ ___ ILl 5.87 __ B_ ___ 25.9 ...__ ~._L~,L_ ...._._.1Zc.8_. ...._.2,65 _._. 1504 7.35 12.8 6.45 1_ _ _ ~+-.. -..3~.. -31.8 1:\.7 .............21.8 ...... _.~J-'_. 18.9 7.52 15.3 __6cCJ~ 12 9.3 8 ()J2.._ . __.6,-4.'1:._._ __--'''62....._. 5.57 3.81 4.83 3 34 __ . . ._.....I.CJ..._._ 14.2 10.1._ 9.77 533 846 _._5S6 __ ~.~. 4.89 20 22.3J..'1.:~ _. . ....... 153 ...._._.. 7.53 13.2 7,~ _ _1_1,~_.. 6.1'9_ 125 22 .._ 2690......1S.} ____ .....1.8.:.5......___. 8.10 160 844 13.8 7.42_ 25 3404 17.1 23.6 9.02 204 940 17.3 .f: L -_ _ _- - ' - _ . 28 41.8 __ 18_.5_ _ _ _ 28_.7._. 9.78 24.8 10.2 20.5 12 ..............
_~_._~ __.
_. _.___ =25"-..
__
=:-.5
Association of Structural Engineers of the Philippines
.----.---. ------... Ll'llglh clf Bolt in Ma in Mcmbcr
DiHIIH.'I l' r
of Boll d (mill )
L
..---.----.----== :_:_::'_c_ -,.-c:.-:--c.----.-.-----.---..•.--.-...- ....- . __..~_...___ . _ _ _ _ S I'I ~!f:~G lli~ U I~i!!<'I·cr l<>. listill ~'3 I!!!:.21L __ .. _....._._.. __._ .. _.-- .. ...... 1__..__.____ ._____ -''--_. __...___ ~_ _ _III.__..___... _____ ._._-'-".__. ___ ._ .. .
-~- -~.--- .-
Pa rallcl to Pcrpl' fHIi (;rain ('lIlar to " .'".._" .. ~ _ _ ~~. __ I' Q
Parolll cl to Grain w • • _._. _ _ _ _ _
I'
Pcrp cnd i- Parallcl to Pcrpcnd i. Parallcl to PcrpcndiculHr to Grain tul ar to G I' ~lin t ulnl'to ._0 .__ Grai~ .. _ . _ ._._ _ ._~; rail~ ___ __ .. _______ ... _ _ .__Q.~~. ~~_ Q Q Q I' I'
(mm) ___ •_ _ ._ . . _~_ ._. ___ ._ . _._. ____ . _ _ ___ - ..- j. - - = c - - . - - - -..- ... ~~.- . . ___(_1)___ ._ • _.G L.. _. (1) (4) _ 1-__ (6) .. __ S!.l..._ . (8) _. [email protected]
12 16
140
150
'--"'20-" ·····--22-·- ..-.
938 14.2 22.3 26.90
·
__ ~._ 4 1.8 14.2 22.3 22 26.9 25 34.6 -28- - ' 43.5 25 28 16 20
----i2l,.---..
12L_
6n 10.1
6 44
15.3 17. 1 18.5 9.59 14.7 16.7 19.7 21.9
18.5 23 .6 28 .7 9.76 15.3 18.5 23.S 29.9
9.77
14:":l" ·····--· i~G"··--
3 65 5.3:'
-- - - -
557 8.46
----753--··--m 8. 10 9.02 9.78 5.06 7.78 8.84 10.4 11.6
3.8 1 4.83. ___ 334. , 5.56 7.33 4.89 - '7 .85·-·-···--iT5-··-6~89 8.44 13.8 7.42 9.40 17.3 8.26 - - IO.2 -·--..-iO's ----S·9S-5.28 7.33 4.64 8. 11 11.5 7. 13 9.2 1 13.8 8.09 10.9 17 8 954 12.1 22 1 ---~6-
.-~:---j
16.0 20.4 24.8 S4 5 13.2 16.0 20.6 25.9
-.-.----- -'-16-'-- ···· 14.2 · . "'884'-'- -''9'j'2- '-" 4'-6(~- - -842"-'-'''"'486---732'--- ' -"427 - -iiJ'- ----.............--.-----.--'.------.- .... ........:....---.~.-6.82 . . 180
..._. __ ............._22-'~_ . ....._ . l~J......_.._. . .._...1.5..2..._. __._L45
·-·. ~ · 22
16
26.9
16.6
18.5
~~= =:i~:~== :=.::~~. ;
== :=:
8.75
:;~
._L7!:....__.!.!.:i.._ --~C;:---j
8.44
4.73 7.30 4.15 --7:61-- " - 1-1-.4-.- -6~69-
9. 12
13.9
8.01
~~r' -'''-:~~ ''-::::~* ::'- ~~0--
14.2·- ..··.. ·8~59---·-9:75-·--- 4.54
·· ..- 20 ·· · ·· ·-Z2.:1·- -I3S ---....i5J"-
I 3.2 _ 16.0
·-"'"'"7.36---"13~2· -·
-
16. 0 ._ ~~_ 13.9 7.90 20.7 11.4 17.9 10.0 _ _j_--,2~8:-__ 25 .9 13.8 22.5 12. 1 16 8.44 4.61 7.30 4.05 - . -- .. 20 13.2 740 11.4 6.50 200 22 16.0 8.84 13.9 7.77 25 20.6 113 :-:.._ =~-I7.8_._ 9.9 1_ . ~-i8--~4i'6'"'-'29.9-' 25.9 139 22.4 12.2 --- - -1-·-;:: 20'--22.2 12.7 --1 5.2~" 13.2_._ .....::6.97 11.4 6.12 __ 22_ __ 26.L_. 15. 1 18.4 15.9 _~.:~_ 2 _ .__ J3.9 ____ 7.3 1 25 34.7 19.7 23.8 20.6 10.9 17.9 9.54 230 28 43.5 24. 8 299 25.9 13.7 22.5 12.0 ._ 32 56.8 31.9 39.0 33.8 17.5 29.3 15.4._ 20 22.2 12.4 15.2 13.2 6. 81 __ __-IJ.A ·.·_. 5.98 . 22 268_ 14.8 18.4 16.0 8. 15 13.8 7.16 240 ~ ___ ._ .._ ..~~L._ . ._._1 9.4 23 .8 20.6 __ 10.7 _ _ . .....!22. . ___ 9}2._._ 2S 43.6 24.6 29.9 25.9 13.5__ . __ ._~?':'~ ___ ....J.IY__. .._._---_. --.32 57.0 3 1.9 39.1 33.9 17.5 29.4 15.4 - -..- -'22 - '-26~ --i-;f4'- -'18:4- - 7:61--- - 15.9 .- 7.93 -. 13.8 ' '-6~ -:C:::---f--::-~--II -~'-;;--' --;,-::-- ---~ - . - -- . . - - - - - - - - . _ - - . - - . -25 34.7 18.8 23,R 9.93 20.6 10.4 17.9 9Jl2........ 260 28 43 .5 24.0 29.S 12.7 25 .8 13.2 22.4 11.6 - 32--- 56.7 3 1.5 38.9 16.6 33.7 17.3 29.2 15.2 190
22 25
26.9 34.8 43.6 14.2 22.2 26.8 34.6
16.3 20.7 25 0 8.37 13.5 16.1 20.5
-"'''m-''
IS.5 2:1.9 299 9.90 15.2 18.4 23.8
8.63 10.9 13.2 4.42 7. 13 8.48 1(l.S 13.3 6.69 7.98 10.4 13. 1 16.8 6.54 7.S3 10.2 13.0 16.8
th
Nationa! Structural Code of the Pililippines 6 Edition Volurn e 1
6·!)01
Leng(h of
CHA PTCH
(j
Wood
......... --............ ::=.~=== =:=::::.:.~:~ ····~i;iiCii;si;·R·{jij!;(RCic·~i;;-ii;;ungiiiTablc6.2j- - ·~~====~.~ -==. --.. -~---.,---.---- - -----' , -~- - - _ __-"L ____ ---.-..1X--- .. Dialllt.~ ('r
Holl in
of Bolt d (111m )
Main Member
Parallel (0 Grain
Perpendi· c-ular (0
Grai n .... _--,-,--.. - ....
Q~ --
L (mrn)
---(1)-'-" --'(2)'''-
290
~4-32 25 - -2 -f -
f-____j_····_..·_·-·-iT72-_·-==· .~ ._
__43.4 _
18.1
Pcrpendi. cular 10 Grain
- j;---' - -Q- - --
308 17.8 22.7
--56.8-- · ·W:-4~-
_.
17.3
Parallel to Grain
---'-p-" -
(S) -------w-.- 23.8
9.53
---.1l§- ~~ __ J_~_
56.9 34.7 43.5 34.7
-
--- "(4)-- -
(3)
·-~- .. - -·--··- i5---··-·-3-4-.6--~
280
I),u"a llcl to Grain
39.0 23.8 29.9
16.3 9.39 12.0
_
--39.0----T6-:-i·-·. 238 _ ..._ .._~Jc~ __ .
l'crpcndi. cular to
Grain
Parall el to Grain
'- - Q- ' - --"-
(7)
(8)
20,(,
9.94
~_ 33.8 20.6 25.9 33.7 . 20.6
12.6 17.0 9.79 12.5 16.7 9.51
Pcq;cndi. ('uJar to Grain
p --' - -Q"-
--- (9) -- -~(TO)-
17.9Sj; 22.4 11.129.3 14.9 17.9 8.60 __._ 22_.4___ ~_1.!Ji_ 29.3 14.7 17.8 8.36
-_-_~;:+ :.:'-.-_..- --~.- . . -··~H-·- ---~J--·· -·-iH-·----iH-·-- ---":-7~: .: :~-+--;::;~H- - :~~F- J
L-_ 30_5_-'-.
Association of Structural Engineers of tile Pililippines
, Ullit 'md Holt ill .. , , . AlIow;lblc I, o'HIs in SC'l,.so lll'd Wood (Normal DUI"ltion ) for Onc Shc'lr·Phte . Table _ _(,:._J8._= ._--------.-
Sillgl~~_hl'lIr .
Loudrd "nralldln Gndn(O"J
NUlI1bt'f
Sh(',U"
nolt dilllu.
I'lale diam.
(111m)
(mill)
of Fll t't of Ilit-n' wilh ConIlN'tors /JC
Nt'!
Minimum
Thickness uf Lumber
Edge Distam'c
(mill)
(mill)
Samc
------ --_._---- .-~~ .._--_. I
oj
=. .
__.. -- - _._- _ ..
II
- -- . ..._. 11 .70
I ·HII
minimum
. ..
··-·-··Allownhtc I~~ld-i;~~Connector Unit nnd Bolt (kN) Sl'·l'(: il'3..g!:OI!l!._~ I
•1{)
Llladcd Perpendicular to Grain (9U")
_---------_._.._..-
----
Allowahle LOll(i per lJ niland HoH
Edge Distance (mm',
C()lllll'Cl 0r
____ (k --- _._- ---~ ===---fu~~s GrOlll ~L.
Un luaded
LoadedEdgl'
Edge (min.)
III
------
_
45
10.10
min imulll 70 m
more 2
()5
20
40
minimuill
9.rJ74
10.90
45
7.g28 45
45
1:"1.26
50
minimum
J
1.03
70 or more 45 or more 70m
9 .5 19
more 4S
GS &
._-----
th ic ker 40 minimum
----
..
14.01
I 1.70
10. 10
19.15
16.46
1'1.1 9
- . mininlUIU 70 or
morc 70
minimllm 95 or mor(! 70
I
minimuill 4S &
th icker 4.1 ml ni Jl1um
? l.I7
17 .66
15.2 J
J4.I O
11 .74
10.14
95 or Illore 70
minimum 95 or rn on~
13. 12
\ 5.75
50
70
)1.;-10
minimu lll 95 OJ
more
2 100
I ~A 6
65
15. :\9
I:U5
70
70
20 I
75
20.JO
16.72
50
1,1.'16
70 minillllllll 95 \)r
more 7() minillluln 95 or more 70
II
III
8.1 40
6.76 1
5Y72
9.1:130
8. 184
7.072
6.316
5. 293
4.537
7.65 1
6 ..'6 1
5,47 1
(,.405
5.5 16
9.296
7. 740
6.672
K. 140
(,.761
5.87 1
9.8:10
8. 1
7.072
lIAS{)
9 ..
8.229
13 .&30
II .52
9.964
12.280
10 .23
8.807
14.810
12 .37
8.184
(,. 805
5. 871
9 .8 75
8. 229
7 . 117
9. 118
7(
6.583
II J130
9. 163
10 .720
8.9'10
7.695
12.940
10. 7fiO
9.296
I
...-
7.605
1--
,
._--_.
~
-10
19.:'7
mill iIllll III
_AW_' _ _
I ________.__ ..1 _______ --- _.__.._---
17Nl
1. 17
'1 5 III
15.2 j
9.697
K.362
II. 740
10.10
12.280
10. 2~O
1·:U;}O
12..
11.650
Ill,lr,'
!
1(l .·Hl
70
14. 19
1l1inill1U11l
I
\)) , )1
,
IIA XO
70
I
- --- ~-
_~~~_.L
I
9 ..)(
I:uno
,
12.0 I (l
i to.
Hl(IIl·
-_._-------'------,--_.- L __ ..
o
14 .()60
minimum 90& [hid-.n
10.68
,,
,
I I..
____~__
o
8 .807
6·56
~ .- --
Shell!"
Plate dilllll. (mill)
CHAP1£:H 6 · Wood
. _-- , -_ ..... . _.•.._---
Bolt dialll. (111m)
,--.
Grain (0")
Number of Flll'l' of I'ieee
Net
Thil' kncs... of Lumber
wilh
Councc-
(Illm)
lor ... of
DislllllCC
(null)
-- - -
- ---.,.. -
Conllector Unit IIlId Holt (kN)
.. ..•.
S }ccies Grou )
-. I
..
-2 1.17
45&
-
Allowahle l..{lad,)Cr--
Minimum l.:dl:c
SIIIIlt.'
._1!g.I~~_
.1.olldcd 1)llrallcilO
II
III
(kN)
l<:d~c
(min.)
- - -'
Loaded-
95
15.2 1
more
14 .10
! 1.74
16. 19
13.12
22
2
70
65
I HAll
15.39
13.26
70
minimum 2(}.IO
16.72
14.46
thicker
2 1.17
17.66
!5 .21
minimum
7.! 17
9. 11 8
7.606
6.583
'"
11 .030
9.1 63
7.917
70 minimum
10 .720
8.940
7.695
95
'"
12.9·1()
10,760
9.296
70 minimum 95
11.650
9.697
8.362
)01 .060
11.740
10.10
I:U80
10.230
0 8.807
I·uno
12.370
10.6&
'"
"'
70 minimum 95 more
Association of Structural Engineers of Ille Pililippines
10.68 ()
8.229
more
90
12.J70
9.875
more
15 &
14 .810
5.918
more
100
- -- -.
6.805
70 minimum 95
11.30
thicker
III
II
--- -----
~.184
more
50&
'"
70 minimum 95
10.14
_~~l'~S Gro~~=--
Edge
_.__.-
th icker
45 min imum
Conllector Unit alld nul{
Edge Distallce (nun)
. - - - - .Unloaded
- - -11,66
_._---- --_.._-_•. _ ------ -_..'- --,. . -" - "'-AlloWl~bi;'- Loaa" jiC~'----" -
'"
CHAP TUl G . WOO(j
6·57
_._ ----_.. ·, '(Joilled
lUng diufl\. (n ull )
Nu mbcr or FII('c Bult
of I'i('('("
diaUl.
with Cu nncr-
(mill )
t OI'S
of
Luad cd PUnlll('\ tn Nt't Thickm'ss of Lumhel'
Minimum
(mill)
(mill)
Edge Distllnrc
Sa Ill('
-------All ownhlf.) Load
25 minimum
C(JIIIIC("l or Unit lind 11011 (kN) _.. ..--.fu ceics G roup 1
II
III
'i.J:j~
4.804
4.181
.87 1
40 & thicker
._-
•.
p C I'
.-... _....__.- .- ---
--- -- _._--..-- _.. _ Holt ----- .. _---_.
50
l"(I:I
Grain (0·)
5 . 29.~
Edge Distance ( mm )
-
Unloaded Edge
(minimum)
LoadedEdge
32 millimum 50 or more )2 minimum 50 or more
4.581
12
.HS
4.804
.871
5.293
4.51\1
25 minimum
'.(}{X)
7.2()6
6.227
0.01
8.%5
)2 mi nimulll 50 or morc 32 minimum 500r more 45 minimum 60 or morc 45 minimum
4.11\ 1
50 & thicke r
40 & thicket
7.823
60 or more
16
2
8 .(X)6
40 minimum
50
.852
7.206 7.962
6.227
45
6.89·1
45 minimum 60 or more 45 minimum
60 or more 45 minimuill 10 .0 1 I();1 1
65 & thicker 25 minimum
8.985 9.385
60 or morc
7.828 8.1'0
55 minimulll
80 or morc
14 .()6
40 & thicker
85
20
Ik N) S ceics Groll ) I
.
• .-
II
III •.
2.758
---
).20)
).20)
3.647
3.647
3.158
3.5 14
3.514
3.069
4.003
4.003
3.469
32 40 minimum
65
AllowRhlc Load per Conllector Ullit and Bolt
12.63
10.94 55
55
2
40 minimum
55 minimum 80 or more
10 A!
9.385
8.140
55 minimum 80 or more
-_.. -- '---- .------
National StrLlctural Code of the f»l ilipprnes 6'" Edition Volume 1
3.20)
) .203
2.758
3.647
3.647
3.158
3.5 14
3.5 14
3.069
4.003
4.003
3.469
'.804
4.804
4.181
5.'17 1
5.471
4 .759
6.005
6.005
5.204
6.805
6.805
5.916
4.804
4.804
4. 181
5.47\
5.47 J
4.759
5.293
5.293
4.581
6.716 6.672
6.049 6.005
5.249 5.204
7.562 6.939
6.805 6. 227
5.91 6 5,427
8.229 9.385
7,428 8.451
6.45() 7.295
11.I2()
10.0 10
8.674
6.9:19
6.227
5A27
8.229
7.428
60450
--_..-
-" -" -- -' - -'- l ~-
._ .._.-
-- - --- - ~-- -, -- -.
i 'l 't)4)llll'd
Hing
"'~j (mill)
Boll cliam.
Number of Fal'e of I)iccc wilh
( mill )
CUllIle('·
torS or Sallie
- --_... _----- -
. -- ~-. -- , - --- -
Loaded I';lrnllel Itl Grain (0")
Net Thick· uess of Lumber (mm)
MinimulII f<::dgc Distallce (mOl)
Allowa.ble Load pcr Connector Unit ~nd Uolt (kN)
Loa(ktll'l'rIH'IHlkular to (;ruill (I}O")
. F
..
=-~.§)(!cics Gro~J~._._ "lj~11 I
Boll
.,
_
Table - (conlinued) -_.... 6.19 ..•.....--- ._---
50
. 11.39
65
)) .03
75 &
14.06
II 10.27
I J .74
III
F (min
~-.--- .
---- ._ --9 .029 h.71 X
R.09:,)
7.U?K
7.R28
6.605
10.320 9.365
9 .296 8.1151
K051 7,29:;
80 or mor('
11.120
10.010
8.674
70
8.362
7.s! 7
6.494
95 or more
JO .050
9.029
7.8n
7() minimu m
10.850
9.786
8.451
95 or !!lOfe
!3.030
! 1.743
1(),19
8.162
7.517
6.494
9.7&6
70 minimum 90 or Ill(lfe
10.050
9 .029
7.828
9.029
8. 139
7.072
10.59
70 minimum 95 or more
10.850
9.186
BA51
70 minimum
10. 190
9. 163
7.962
&.&%
RO Of 1ll1)rC
10.1 9
55 mil1irnull1 80 or more 55
minimum
12.63
10.9<1
lhickcr
m ininwllI
I
12.54
25
11.30
9.786
minimllm
16.32
40& 100
thic ker
20
2
14.68
12.72 70
70
12.54
40
11.30
minimum
50
13.57
12.19
65
15.)0
13:101
11.92
95 or more
12.230
10 .990
1).$19
75&
16.32
14.68
12.72
70 minimum 95 or more
I C.B50
1) .700
8,45 1
13.030
11.740
10. 12 ..
thi cker
Association of Structural Engineers of tile Pllilippines
CI-lAPTEfl 6 . Wood
6·59
Taole 6.20 - Allownbl c Load.Ii in Seasoned Wood (No rmsl Duration) for One Split.Ring Unit and Bolt in Single Shear ._ _ .
- - -- .. - - --
No. uf Flicc uf
Split Rill": Diam. (mm)
nul! DiIUII. (1II1ll)
Piece
with COlillce· tors of
- - --
Net Thick· nc ....~ of Lumber (mm)
SUIIIC
Bolt
····- - T- - - -
M in. Edge Dis lalll·(.'
(kN)
III
40 & thicker
Edge dt'itlmec
(1II1n)
40 minimum
(kN)
S ·des Group Unlolld('d Edge (Min.)
Loaded· Edge
III
(56)
5,471
4 .7 15
45 minimum
70 or more
7.784
6.494
5.560
I:U5
11.12
9519
45 minimum
7.873
6.583
5.649
70 or more
9385
7.784
6.672
45 minimum
(58)
5.471
4.715
70 or more
7.784
6.494
5.560
9.252
11.12
14.19
17.03
7.962
9.519
12.23
70
45 minimum
7.872
6.583
5.649
70 or morc
9.385
-'.784
6.672
70 minimum
9.875
8.229
7. 11 7
11.830
9.875
8.496
9 5 or more 25.53
thicker 40 minimum
70
17.92
21.26
14.90
18.37
12.90
50
20.599
17. 17
14,8 1
66
25.04
20.90
18.06
75&
25.53
th icker
---._._-_.•.
II
7.962
13.25
40 &
2
I
9.252
11.03
25 minilllum
20
Allowable Load Per
Connector Unit And lIolt
45
50 & thicker
100
..-.
11.0.1
45
12 2
-
LUlld ed P('qx'ndicular to Grain (90°)
---- --_._------_._- ---- - -- ----- - - - 25 minimulll
64
II
I
--
-
S H,'eies Groun
(111111)
-
L(ludcd l'itrallel to Grain (0') Allowahle Load pcr CmHlcCI(jr Unit und Holt
..
21.26
-----..-.-- ._.
__•.-
1837
..---_..
-
70 minimum
14.810
12.320
10.6)0
95 or more
17.790
14.810
12.110
70 minimum
10.360
8.629
7.413
95 o r more 70 minimuill 9S or more
12.450 11 .970 14.320
10.360 9.963 11.970
8.985 8.585 10.320
70 minimum 95 or more
14.540 17.440
12.100 14 .540
10.450 12.540
7()lllinimum
14.810
12.320
10.6)0
17.790
14.8 10
12.770
95 or more .--~--.
-_._--
National Siructural Code of Ihe Philippines G'h Edition Volume 1
__
-_.
... ..-_.
6 ·60
CHAPTE:11 6 ·· Wood
Table 6.21 - Common Wire Nails and
-
Length (mm)
N A
I L
S
Loads in Seasoned Wood-Normal Duration -- -- .~
Desi~natioll
'(1)--"
Spikes~Allowable
(mill)
into (he Member Holdin1!. the Point (N ) Species Group IYII I III
(4)
(5)
(6)
(7)
(8)
805 750 690 685 590 495 455 4011 345
550 510 470 435 400 340 31 0 275 235
340 3 15 290 265 245 210 190 170 145
2 15 200 180 170 155 130 120 \05 90
Diam eter
.
,
(2)
150 125 11 0 105 100 90 75 65 50
(3)
150 140 125 115 100 90 75 65 50
..
Withdrawal Loud from Side Grain per 'Latc,;;! LOlid in Side G raj~\.( N) '"'' 25 nllll or Penetration of Nail or Spike
Size of Nail or Spike (mm)
6.5 6.0 5.75 5.25 4 .75 4.00 3.75 3.25 3.00
~- .
Species Grolll)
- ,- .' . - - - -
I
_._.. __._- ..._ - .. J2L._ ,.
II
- -..III
(10 )== J.!J.L. -=
I 1320 1180 1045 920 825 640 555 465 370
P I K
E
S
3/8 3/8 150 140 125 110 100 90 80 75
2 15 180 150 140 125 115 100 90 80 75
9.5 8.0 7.0 7.0 6.75 6.0 5.75 5.25 5.0 5.0
1035 860 780 780 725 675 620 570 530 530
705 590 535 536 495 460 425 390 360 360
435 360 325 325 305 280 260 240 220 220
275 230 205 205 195 180 165 150 140 140
2020 1535 1325 1325 1185 1060 940 830 740 740
,
1735 1320 1140 11 40 102() 910 805 7 10 635 635
935 84() 750
665 585 525 525
,-;-;. ----_._-,.. - _...
" SOURCE. PllihpplOe TImber DesIgn StandlUds (1. E. Rocafort and 1. O. SIOpongco) November, 1991 (FPRDI Terminal Rep0r1)
Association of Structural Engineers of the Philippines
1425 1085 935
Ji~f775
930 830 735 650 580 450 395 325 260
1iJ5 1010 895 790 705 550 480 400 320
.- - -_ ... S
IV
695 615
540 48.\ 375 330 275 220 -
1190 90.\ 780 780 700 625
555 490 435 435
CHAPf Ul E . Woo(i
-
--- ~~~~_ ._ _ _ __
Table 6.22 • Allowable S >ans for 50 mm Ton Jlle and Groove Decking ---- - [ - --
J./ ~%;;,~~~"
.__.,_
-
IlEFLECTION J./ MIT ,--_
.
(N"~"" I
j- ~N~::,:~·-·~=I
I I O?
1171,)() 1763.84
Roofs
-------... --~--.--
O.95H
1/360
. -
---'~3-7---- =~~~~==Y--,II.'l;;~·-·=='== --~~J~;;'''--.----- =~_. . . ov
12(X)
1.916
- - -..-- - - - -...-..-
6 ·6 1
1/240
..
J 763.84 2(;45-.-;;7;-··· . ··
~·--·-234i60-·--·-
I.H60
. ··-
+ _____._____J__·-_-_-_··_·"'35;Si"''r'''(;8::--_····_-===-1 ..-.
/3c:6
0.958 1350
1/360 1/240 1!360
1.437
1.37H
\667 .38
1.860
2101.01.5 2501.07 - - 2790.45 " - ' - -
------I.'-)1-6--- ' --~==-.----ill.:'4~O'=--:...---- /-----2-.4-,-,-·---1---~31"3C;4".7~6---
+__---;4"'9"'95".2"'5_ _ _-1
_ . __ . _ _. __.._ .. _. __ ._ __ __ _ _.. _ _ ___. 1136
______--I____
1500
J .437
1650
0.958
1/240 1/360
-
-._-··---·s·i 12.38
2.894
11240
1.437 ~::=:'.===:~~"'
_ ... _~._. _ ____.______ ._._.'"._ ..-._--- - - -- . - - - 1 - -.. 0.958
'4.547.40 6890.00
2.067
3045.38 + _____,,4-::54,,7 ".4', ,0c-___
1.437
1/240 1/360
--..- . - .- ----.-.- - -.2.756
·"1724.Q_.__ ~==
4561.18 6876.22
,,·-- c;O<)()j·(;----"-·--·
_ _ _ ____ 3.445 ._ _ .. ____.__ -;9,,';;6:-3.,,7';-1_ _ ... _ 2.480 3961.75 1/360 . 5939.18 ----j----~~-----+--------·----------·~S~~---I 11240 3.307 5939.18 1/360 8922.55
1.9 16
0.958 19S(}
_ __...,'''''8'-;7".4-::8_ ___ 3445.0{)
----,----. · - --)4J"(l.5-. I ----·
_____._______ --7I/"'lo:6
- .•.-.--.•-,-----~ I .916
1800
1/240
_. ___ -""=-36~;Oc.-..- - _ __ ._227~_ .. _._. __
...-~~-~;:.--..- - -- .
_ _ __ ._
- 1 - - -- - . - - __ 1.722 _ --;';1/3~6"'0---+ __ ._ _ _
11360
1-_ _---"l/o;24;:;OC_
1.'240
------ - -----1- ---;:c;,;;"'~;;1.437
4. 14 3
1136
2 894
11919.70 __ _. __ ._.__~Q9Jl.55 __.. _ _
. --- - ----:-.-.. ---.-..--- --·- - - {~:;~~i-·---·
1/360
-----.._--...-.------ ----., ___ _~.~~2 ._. ___._H_ 1.9 16
792350
.____
" -'-'-'-~923z~760;;----1
3.858
"~---'-- --.----~::
_.J!.L22J ()-..~----
Ji360
;1.823 119J9.70 -'1"i2"4"'o- - - - - I - - - .- - - - - - - -j ----"",2'6;'"' 9."'90, ;-----
0.958
3376 ~"-----~1/=36
1-_______ 2100
1 - - -- - - -- -/- 2250
1.437
11240
5.168
-.J..!.§..~7'50- - -..
1.9 16
11240
6.408
17431. _ _---'0(;55';'°,,2.,; 500 '-____ _
1---- -- - - - I - ---:Ie;I3C;6;cO------ _. __._ _________.
- . - -.--------.- -----------·-I---·--;';:~:;:~"'o----2400
-.---.._
0.958 . _- -
'
-.--.--.--.----+----~;;,,;"'~8"-;4(=2;i-_-_ -4.410
11360
14055.60 ---
11240
14055 .60
1.4 37 ---.-.--.~-~'7._---5.856 • ___ ._". __ L...... __ ._. _ ___ _ _ .. _._ ......••• _... "'60 ____________ _ _ _ _._
th
Nalional Siruciura l Code of Ihe Philippines 6 Edilion Volum e 1
___
21083.40
6· 62
CHAPTER 6 - Wood
Table 6.22 - Allowable Spans for 50
mOl
Tongue and GrooYe Decking (Cont'd)
Floors
1200
__ ~
5.788
~~~-_-_-_--_~--,-:;"Z,,~,-----_~-. ~___ '_9~_'--:--c-:c-:---,JL-,---:----:----:-'-,.-'{,..."- -I
--
-~-----6K9(l .()()-~·--
"j
==~-~-=.D~~ ---=--···-l·~=~~~~={,~~~~~~~~:~-- . - -_ ..
Span-\' (lrc ba.\'ed Oil simple ht'am tic/ion with 0.50 kN/I// dead load mul provi.riO/lS for a 1300 N conanu(l{/'d /o(1d fill
.1
(I
.i(X) mm widlll fljp,'> O!
dl'cking. Rando/ll laY-Ill' p('I"mil(('d i'lll(.'cortiu!lcc willi t}w ()TOl'isio/ls ojScctioll 620.8.J or 620. 10.11.9. i.rw))/' r l/ticlall'ss OSJUIIl('(1 IJ/1{) mll1, /W/
Association of Structural Engineers of the Philippines
CHAPTE.F1 G . WOO(j
...
~-~~~~-----
.
(j·G3
Hci~ht and Spacing of Woods Studs ._- ... ..-.-----Hearin' Walls _________~ on~ BCi!!'i~~KYV ails Supporting Supporting Supporting Latcrally One Floor, Two Floors, Spadng Roof and Unsupported Roof and Roof and Stud Height I Ceiling Only Ceiling Ceiline- - - - _ .._....- --------_.._--, (mm) (mm) Spacin2 (mm)
_-- ""-'--_._-- Table 6 23 • Size
~-------.---~.-.--.---.-
~
Laterally Unsupported Stud Height I
Stud Size
~~~
---.~
(mm) SO x 75
-
(mm)
~.-
I
~
50 x 100
250 250 250 250
75 x 100 50 x 125 SO x ISO
~
~
600 600 600 600
400 600 600 600
3000 4200 4200 4800 6(XIO
~
~
--.~.-.---
400 ~
400
{ U.fted heights are d,sf(/nces between points of la{('tal supporf placed perpendicular 10 Ih(' plane of Ih(' waf!. permirred where jllstified by an analysis. 1 Shall not hi' used in eXlerior walls.
Seismic Zone
2
-
Condition One~story,
top of two or
Table 6 24 - Braced Wan Panels I Construction Method ',J 1 2 5 3 4 6~_ 7 X X X X X X X
three~story
--_..- -First- story of two~story or X X X second-story of three-story --_. First~story of three-story X -- X One-story, top of two~story X X or three~story First-story of two~story or X X second of three-story
.~--~
4
First-story of three-story
X
X
X
X
X
__..
.
X ...
'XT X X --- - .. ~ X' X X X
~-
8 X X--
II/CTNlSeS
--
4()()-~~~
----
600 600 600 600
t------.~ ~----
in IlfIsufJPorll!d helghl
(if{'
Braced Panel Location and Length" Each end and not more than 7500 mm on center
--X ~
~
X
X
X'
X
X'
X
X
X'
X
X'
X
~
1111.'; (able specifies mill/mum reqUirements Jor braced pands whu:hJonu /rIterlor or exterior braced walllmes. See Section 620.10.3 forJull descriptiol/. ) See Sec/ion 620.10.4 for altemate braced panel n~quirement, Buildillg length is the dimensioll parallel 10 the braced wall length. 5 Gypsum wallboard applied to suppons at 400 mm on cell IeI'. 6 Nol permiffedJor bracing cripple walls in Seismic Zone 4. See Section 620.JO.5. 7 The reqllired lengths shall be doubledJor gypsum board applied to only olle filce oj a braced wall panel. I
National Structural Code of the Philippines 6'h Edition VolUlne 1
Each end and not more than 7500 mm on center Each end and not more than 7500 mm on center but not less than 25% of building Ieogth' Each end and not more than 7.5 In on center but not less than 40% of buildin~.~~,~~....
6·64
CHAI"TEfl 6·· Wood
Table 6.25 - Cripple Wall Bracing .
Seismic
Amount of Cripple Wall Bracing 1,1
One-story above cripple wall Two-story above cripple wall
lOmm wood structural panel with 65111111 at 150 I 300 111m nailing on 60 percent of wall ienO'th minimum lOmI11 wood structural panel with 65mll1 at 100 1300 mm nailing on 50 percent of wall length minimum
(mm)
__ .~~.ne __
4
----
Condition
_-
"-_..
or
l0l11111 wood stnlctural panel with 65111111 at 150/300 mm nailing on 75 percent of wall ----_.. J~.g.!h n~]il11ul11 Ollc~slOry above cripple lOmm wood su'uctural paneJ with 65mm at 150 / 300 mm nailing on 30 percent of wall wall length minimum Two~story above 10m111 wood structural panel with 65m111 at 100/300 mill nailing on 40 percent of wall cripple wall length minimum
2 2
or
lOmm wood structural panel with 65mll1 at 150 / 300 mm nailing on 60 percent of wall
length minimum I
2
-
Braced panellenglh shall be or least two times the height of the cripple wall, bitt not less 1/)011 1200 mm. All P(wels along a waH shall be nearly equal in lcngth and shall bc nearly equally spaced along the length of the wall.
Table 6.26 - WOOD STRUCTURAL PANEL WALL SHEATHING -Minimum Thickness
Panel Span Rating
(mm) -,,-_.
10 10,12 10,12 I
I
(Not eXDosed to the weather, strength axis Darallel or nemcndiculal' to studs)
1610, 1610, 2010 Wall -- 16 o.c. 16/0,2/0,24/0,32/16 Wall 24 o.C. 24/0, 24/16, 32/16 Wall - 24. o. c.
Stud SI)3cing (mm) Siding Nailed to Sheathing under Coverings Specified in Section Studs 1--_ 620.10.3 Sheathing Parallel to Sheathing Studs Perpendicular to Studs 400 400 600 400 600 600 600 600
In }'(ference to Section 620.10.3, biockmg of honzonlai,loints is not required.
Table 6.27 - Allowable Shears for Wind or Seismic Loading on Vertical Diaphragms of Fiberboard Sheathing Board Contraction for Type V Construction Only) ~-
Size and Application
12 x 1200 x 2400 mm 20 x 1200 x 2400 111m I
Nail Size
_._-_._-_. Galvanized roofing nail 40 mm long, 10 111m head Galvanized roofing nail 45 111m long, 10 111m head
Shear Value in 75mm Nail Spacing Around Perimeter and 150mm at Intermediate Points
182.5" 256
Fiherboard sheathing diaphragms shall 1101 be used 10 brace ('onereI(' or III(1S01ll), walls. The shear vallle may be 780 Nfor 12 by 1200 by 2400 mm.liberboard /lail-base sheathing.
f\ssociation of Structural Engineers of the Philippines
-
I
CHAf'TEH 6 - Wooel
6-65
Table 6.28 - Allowable Shear for Wind or Seismic Forces in Pounds per Foot for Vertical Diaphragms of Lath and Plaster or Gypsum Board Frame Wall Assemblies I Type of Material
.
Thickness of Material (mm)
Constrllction
22 mm
Unblocked
I,
Expanded metal, or woven
wire lath and porliand cement plaster
I.
I,
Shear
Value -------
150
2628
125
1460
--
Minimum Nail Size 3 (mill)
-_.._----_._--------40 mm long, 10 mm head Staple, 22 mm legs
I
10 mm lath and
Gypsum lath
2.
Nail Spacing 1 Maximum (mill)
Wall
Unblocked
! 2 111m plaster
Staple, 30 mm long, 6 mm head,
plasterboard blued nail
-12mmx600
3.
ml11 x 2,400 111m
Gypsum sheathing board
Unblocked
100
1095
Blocked
100
2555
Unblocked
175
1460
45 mm long, 10 mm head, diamond-point, galvanized
12 mill x 1200
mm
12 mm x 1200
mill
175 Gypsum wallboard or venecr base
4.
11mm
2 mm dia., 40 mm long, 6 mm head) or wallboard (2 mm diu. 40 mill long,
Unblocked
100 175
Blocked
1460
r--100 175
1825
6 mmhead)
1825 2190 1679
Unblocked
100 175
2117
(2.5 mm dia., 45 mm long, 6 mm head) or wallboard (2.5 mm dia. 50 mm long, 6 rum head)
2117
Blocked 16mm
100
Blocked Two ply
Base ply: 225 Face ply: 175
2555
3650
Base ply - (2.5 mm dia. 50 mm long, 6 mm head) or wallboard (2.3 mm dia. 50 mm long, 6 mm head) Face ply - (3.0 mm dia., 60 mm long, 6111m head) or wallboard (3.0 mm dia., 60 mm long, 10 mm head)
-~.-
J
111ese verfical diaphragms shallllof be used to resist/oads imposed by masolZl}' or concrete construction. Values shown are for shorl-term loading due to wind or due to .I'dsmic loading. Values shown l/Iust be reduced 25 percent for normal loading. The values shown ill Items 2, 3 and 4 shall be reduced 50 pen'(!l1Ifor loading due to earthquake ill Seismic Zones 3 and 4.
Z
Applies to nailing {/{ all .wuls, top and bottom plates, and blocking. Affel'l1ate I/ai!s lIIay be u.w!d {frlwir dimensiol)s are 1I0t less than the !'pec[(ied dimension.
National Structural Code of tile Pllilippines 6'h Edition Volume 1
CHAP TEI, Ci - Wood
6-(;6
Table 6_29 - Allowable Spans for Particleboard Wall Sheathing J (Not exposed to the weather, Iong dimenslOll o f· the panelI paralleI or perpencrleu I ar to stu(I s) Stud Spacing (IInll) -
I
Sheathing under Coverings Specified in Section 620_10_3 Parallel or Perpendicular to Studs
GRADE
THICKNESS (mill)
M-I M-S M-2 "Exteri or Glue"
10
400
400
12
400
400
/"
Siding Nailed to Studs
referellce TO Sec/ion 620.10.3, blocking (If lwrizoll{a! joims i.I' 1101 required.
Table 6,30 Scientific Name of Philippine Timber Species J.
Malabayabas (Tristania spp.) iuc ludcs:
8_
Dangakalan (C. obHquincrvium MelT.)
Mnlabayabas (1'. dccorlicata MelT.) Tiga (T. micrantha Mcrr.)
2.
Bitangho! (c. blancoi FI. & Tr.) Bitaog (C. inophyl1um L.)
M:mggilchapu i (Hopea spp.) includes:
9.
Gisau (Canarium spp.) includes:
Dalingdin gnn (H , foxw orlh),i Elm.) Manggachapui (H. aCllminala MelT.) Yakal-saplungan (H. plaga!a (Blanco) Vid.]
3.
Dull t [C. hirslltum Willd. Forma lllultipinna!u m (Llanos) H. 1. Lam] Gisau (C. vriescanum Engl.) Pagsahingin-hu log (c. ealophyllum Perk.) Piling-liitan (C. lu zonicum (lliume) A. Gray]
Nnrig (Valica spp.) includes:
Narig (Y. manggachapui Blanco spp. manggachapoi) Narig, Thick-leafed (Y. pachyphylla Mer!'.) 4.
10.
I
r.
Malaanonang (Shorc
12.
Dao (Dracontolllclon spp.) includes : Dao ID. dao (Blanco) MCIT. & Rolfe] L:unio {D. cdu!c (Blanco) Skee ls.)
Malasaging (Agiaia spp.) includes: no· ilo IA. iloilo (B lanco) Merr.] Kuling-man ok lA. luzonicnsis (Vid.) Merl'. & Rolfe) Malasaging (A. diffusa Merr.)
Binggas (Tcrminaiia spp.) inc ludes:
Binggas [T. ci trina (Gaertn) Rox b.] Kalumpit (T. microcarpa Decne) L.1nipau (T. copclandii Elm.) Sakat (T. Nitens Frcsl.) Talisai-gubat (T. foetidissim:l Griff.) 7.
(Shorca spp.) includes :
Antipolo (Anhocarpus spp.) includes: Anlipo lo IA. blanco (Elm .) Merr.] Anubing (A. ovalo Blanco) Kubi (A. nilida Tree. Spp. Ni tidn) Nangka (A. hcterophy!1a ulm .)
6.
1~\Uan
Almon (S. ul mon Foxw.) L..luan. Red (S. negrosensis Foxw.) 1.<1uan, White (S. contorta Vid .) Mayapis [So squamata (Turcz. Dyer.] Ta ngilc [S. polyspcrma (Blanco) MCIT.j
Yakal (Shorca spp.) includes: Yakal (S.astylosa Foxw.) Yakal-gisok (S.gisok Foxw.) Yakal-Mabolo (S. c illat.1 King) Yakal-malibato (5. malibato Foxw.)
5.
Dangkalan (Callophy llum spp.) includes:
J 3.
Malugai (Pomelia spp.) includes: Malugai (P. pi nnata Forsl.) Malugai-liitan (P. pinnala forma rc sponda Jacobs)
J4.
Miau (Dysoxylum spp.) includes: Kuli ng-bahui (0. alt issisulll Men .) Miau (D. euph lc biu m Merr.)
Association of Structural Engineers of tile Philippin es
6--61
CHI\PTEP 6 . Wood
15.
Guijo (Shore:l spp.) includes:
2 1.
Guijo IS. guis(J (Blanco) Blume]
Kam'lg()l1g
(Dio~I1.)'f()S
i nd\ld~s:
lVlalak-malak IP. philippcllsc(Perr.) C. B. Rob.] Maniknik (P. lCIlUipCI I()IH1111ll MelT.) Nato W iuzon ic nsis (F. -Viii.) Vid. J Parak -pa lak (P. lanccot\Wlll Bianco)
Malagu ijo (S. plagata Foxw.)
16.
Nato (pa laquium spp.)
!iPP.) includes:
22.
Anang D. pyrrhocarpa Miq.) A nnng-guloll ( D. inelus:1 MeIT.) Ala-lila (D. miudanaesis Merr.)
!>alosHpis (Anisoptcra spp.) includes: Aru (A. brunnea Foxw. )
Bolollg-cta (D. piiosanlhcra Blanco)
Dagang (A. ,HlrCH Foxw .)
Kurnagong ID. phiJippincnsis (Rcs ... ) Gurke]
23.
Kamagong , Ponce (D. pOllcci Merr.) Katilma (D. Ililidll Mcrr.) 17.
Pine, Bcnguct (P. kcsiya Royle ex. Gordon) Pine, Mindoro (Po mcrkusil Jungh & de Yr.)
Katlllo n (Dilknia spp.) inchldes: Katmon (D. Jlhi1ippinen~is Rolre) K:llrnOn-bayani (D. megalanlha MelT.) M(liakatmon ID. luzoniensis (Vid.) Martelli]
18.
24.
Sn!akin (Aphatl
Kato (Amoora spp.) includes :
25. Kol\l) (A. aherniana Mcrr.) Katollg-lakihall (A. m:lcrocarpa MelT.) 19.
Pillc (Pillus spp.) includes:
Bayok (Pterosperrnu m spp.) includes: Bayuk (P. di versifoliu m Blume) Bayok-hayo k.m (P. nivculll Yid.)
Pahutan (Mangifcl":l spp.) includes:
26. Pilllllian (M. a hissima Blanco P:thong-liitan (M. men'i llii Mukh.)
Manggasi noro (Shqrea spp.) includes:
Mangg
assamicn
Dyer.
philippincnsis (Brandis) Sym .]
20.
Mllnggasinoro ng - lakiha n (S. virenccns Parijs)
Apilong (DiplcmcalllUs spp.) includes: Apitong (D. grandif10rus Blanco) Apitong, Basilnll (D. basilanicus Foxw.) Apitong, Broad ~w inged (D. spcciosus Brandis) H ~.gakhak (D. warbugii Brandis) Malapanau (D. Ken'ii Kin g) Panau (D. grand is Blume) Pannu, Lcaf-u.iled (D. cauclalus Foxw .)
Table 6.31 Basic Working Stresses and Modulus of Elasticity for Dry Machine Graded Lumber Machine Basic Working Stress (MPa) Modulus of Stress Grade Elasticty Bending Compression Shear Strength, Fv Tensile (GPa) Strength, Fb Strength, Ft Strength, Fc M5
5
3
4
1.48
5.68
MIO
10
6
8
1.64
8.57
MI5
15
9
12
1.79
11.45
M20
20
12
16
1.95
14.34
M25
25
15
20
2.10
17.23
th
National Structu ral Code of the Philippines 6 Edition Volume 1
forma
CHI\PH' fl r; . Wood
(; ·G8
'!:a hi c_.~:g.!!asi.('. \V.~E.~i Jlgl.:'}ad,s.. I:~1' Nails i'I_I"'.~te..':!l!..!.:'lad!J11!jM ~!LL __.__._ ___ J ~ ulllbcl'
._-_. __.. - _._--_._.- ..-
Grade
(N) _.__ Load--CapHcity ._-- . __ ...._. __... . _._._----_._-.
D*=2.5 D=2.S D=3.15 D=3.75 D=4.5 - -.----. - - - -- + -- -11- - - -- -1- ----·- . - - - - M5 92 112 m 188 25S
D=5.6
D=5
-----+ -- - -- - ---1 378
310 --
MIl)
136
166
204
276
380
c---- - - - - -------- -----..- -- 1- - - --
457
182
222
272
369
508
6 11
M20
229
279
279
466
641
771
779
937
- - -. -- -.---.--.-.-....-.. _·--- - - 1 -- -- - + ----1 - -- ·1- - -279
-·i-::;lmbe~·-
340
...------
340
566
557
- --- f - - - - - - -- -
MI5
M25
------ - -------745. 940
1143
Table 6.33 Basic Worki ng Loads for Nails in Withdrawal (MGL) Load Capacity (N/mmj--·-- - -- -- - - -- -- -
____ Q~~l.
_ I)_~"~!..?_
M5
47
52
59
MIO
85
96
lOS
.__..J M 7L _ __J?~~2 70 ----In
__ _.__ J)=..~______.
84
_
94
D=5.6 ___ _ 105
- - · - --1-- -:- - 1 --,,___--1 154 J71 19 1 -----MIS-- ---1:14- -- ----iSc)--- '- -"68--- ---"'20-1----24-1-- - .. 267' 30{) --~,,____j-__:,,___-__I---_j----
--- MW-
192
-"- -'2 15 - ---24T .. - --T87-- ---"345""- --
M25 259 *D=nad dlal11ctcl (mill)
29C)--' 327 -
---~---
389
466 ._--------- ._---_.._-
---- _._- - - _
5 I8
- - 4~--'581----'-'--'---'-- -.-
Table 6.34 Design Stresses for Machine Graded Lumber Design Stresses --.-.-----.. Allowable Strength Properties (MPa)
MS
Dcndi ng
5
--.-~- --
_._--_
..
Tension Parallel to grain --- ~
3
._- - ' - '-
...... __
Tension Perpendicular to gra in
0.29
-_.
._-
MIO
MIS
M20
M2S
10
15
20
25
6
9
0.29
0.29 12
16
20
4.3
5.2
6.2
-_..•.._ --_.
Compression Parallel 10 grain
4
8
Compressioll Perpendicular to grain
2.3
3.3
.-
15
12 .. _.. _._._ --0.29
----_._030
.-
Shear
..-
Stiffness Propenies (GPa)
---
-,
Modulus of Elasticity (mean)
6.2 -..
Modulus of Elasticity (20th percentile)
--------_.
Shear Modulus
---
8.8
5.1
7.6
11.3 - ---10.1
0.39
0.52
0.65
- ~.-
..
----- .__._--
- - - - --
'--
Associa tion of Structural Engineers of the Philippines
--
13.9
16.4
12.6
15.1
0.78
0.91
I
j
_.
CHAPTEn
I).
6-69
Wood
Tahle 6.35 - (In addition to Table 6.1) \Vorking Stresses for VisualJ)' Stress-Graded Unseasoned Structural Timber of Philippine Woods. -. -..." ·.-.. --.------K(j,;,,-.~-;ri{I-:-.~-s·(;TiAmt-·-~---·----.---- ·-·-~·---·-·-·--··-·--···-SO%S1l
Addilional Spcci(~, (Common and BOlaniral
--iic';;~li-;;g·-
Nilllll',)
and Tension paralll'l to graBI
M~~thlhl.;" --C;;-;;!;rc'~;;i~ - C()mJ;;-~~~jo~;" "St~ar -1k;Jir~g of ));Ir,lIk) 10 [wqlt'ndicuhlr parallcl alld l'laslieily Tt:n,ion 10 grain in pilralkl grain bcnding to grain
'"
1··········1 ._-MPa _ ..
·1····················1
-~>;j"'-"
---..~--
MP;I
- -~'- Mr;;--"-
Modulus
or Ci;ISlicily in bending
CO;I~i);:;;-;::~iw-
C)mprcssion parallcllo
IK~ll)C!\(licular
grain
10 gralll
-- Shcill paralkl
",
gr;lin
--I\W;-'-- ~;-- --
Hl'a
MPa
3.(H
190
.-..- .....-- --,;xX'-··· ....- ... -.....-- - - - - - - - - - - .-.. -----+--- - - - - - . - - --.-...- ..- - ----..- -- ·__· _ - - 1 - - - - + - - - 1 - - - - - - - . _.._. --..-
---.
- - - 1----1-·---
High Strength Group
A Commercial Species
Alupag amo [Litchi chincnsis Sonl), ssp pliilippinclisis (RaJlk)Lcenh.J A!a-a!a (Diospyros mindanacnsis Men.)
.- ..
l3ilkauan (Rhizopho-;:;I aniculata Blume) KatilnUi (Diospyros nitida
--~-.--
28.U
7.98
- - 26,li'"'-
~--..~~ ~~ KubJ (Al1ocarpus IlItlOUS Trecc. snn, nitidus) Narig (Ya!ica mangachapoi .. Blanco ssn. manpachanoi)
Narig, 'Illick leafed (Ymica
3 J .21
'---sJl- ---~--. -~3~.S~,--j-~2~.676~+~16~.735~~---'57.1~9c-+---'S~.O~2c--l---~cc:----j-",-j 2,21 1.66
_._.••...7.92
24.47
8.15
27.04
8.34
-.~~- ..- - 1 1.()4
5.47
10.29
6.42
-2~85'- ·---I-~i.S
2.89
I
16.90
4.95
6.43
5.21
3.42
1.78
2.62
J.53
4.01
L81
pcchyphylla Mcrr)
Tiga [Tristeniopsis micrantha (Merr) Wik &
1-'\\~'~"'~"~h~JL,-,...~_____
~~
=_._I--~~_
..•_
Tindalo [Afzclia '-)0.17 -8~88 ---'Ti~i9--'-"' --·~7ccS"6--I-~3~.471-i-"I8".8"6-1--S~.
Fo,w.)
Yaka!-yamban(Shofca
fakiferoides ssp. faJdfcroidcs) Yakal-malibato (Shore:! malibato Foxw) Yakal-sap!ungan [Hope;] olaMta (Blanco) Vid.) Diosp)TOS sp.
25.05
9.92
.. ~
_.. 29.17
38.22
.--~--
--9.50- -
9.8~
"'-(;:72 ...~ '----2:33- '~'l5---:66-'~ '-~'-(;:ii)"-- -"---'(~i'4'"-.~--I~=c-I-."~~.j--~ ..~---"2.43 18.23 -S,94
2.13
--'-'-4.20 - -
--~
6.13
3.94
1.52
5.44
6.34
3.84
1.65
26.12
6.99
7.97
5.62
1.82
-
8.70
10.[4
6.15
11.18
12.76
9.00
24.67
7.98
8.48
5.71
2.64
15.42
4.99
5.30
3.57
1.65
27.47
7.62
9.44
5_08
3.00
17.17
4.76
5.90
3.17
1.87
26.85
],86
9.82
6.88
3.00
16.78
4.91
6.14
4.30
1.87
6.70
5.60
L80
7.12
3.42
-~,fl:79"
2.64
B. Lesser-Known Species Alllsoan (Cassia javanica L. iavenica) AraClgen !GanophylJum oblio;lUnI (Blanco) Mm,] SSD.
Bansilai (Ochua foxwor1hyi 27.99 9.24 10,72 Elm) SalirlWood (Chloroxylon 32.92 8.40 J 1.39 swicleuia DC.) ._. __~ _ _ _ _ _ ........ _ ._ _ _ .___1_ _ _ _..._
1.93
+__--j
- - . - i - - - - ...-~-..-. _ .._. __._j_____
I-c-~~~~·~-_I_--_l·---I--···· ·-···----- - - - . _...- . - - . -..-
II. Moderately High
- . - - - 1 - - - -+--1
.'lS.t"""""li'''"''.'C'G",to'''';,"-=O_~_--I .___--1 __.___1____--1_ ..___ ---..--.l-----I----i-----I------I--c-I A. Commercia! Species
Aklc [Albizia ade (Blanco)
21.08
7.20
7.36
4.78
2.78
Morr.} . _... _ . __.. __________ _ Amugis 19.48 6.71 [KoordersiodcndfOll
~innalum (Blanco) Mm.)
National Structural Code of the Philippines 6'" Edition Volume 1
4.60
2.99
1.74
--A;;;';~(i)tll" I ;)'m~""'------ -
-'!):':!.'! .I~·I"~}.~ !!Jl ______ _
An; 1I11: ' gllh)( l lJ)iv~ p yn l~
-."
-22.(JO - -
7.02 .-
'-'--'"7.41-'- -7.iij--- -- ~-).:i'i --.- ~I~~r;'- --'4~:W'-
·--ili.2 ()· ----;,-.T5--·-1-------J.41
- - - -j"T,l---
'--;j7,7-- - --TT(~?-' -..-- )
Io:S---- - .Il;,j'-·--
U1 ),fU11·'·I)(·aty'>' (JIii.'m J Jbkh J -'"il i' !i;o(;';T~I-;;;;i;;--····--·· ·---·
--~
....!.l.!!!.(:D.:£!.~t!.l!.~L.!)() 1 1 L ______.._ B iU Wt ~
ITl'fmin:tliil
( G:t ~~ nn.)
18.01'-'
,~ il ri n;1
.......•..
- - -- - - - - - - - - - ----.---.--- ---.-'"-----
'--'-- ~,-'---" -''' '---i~') 1
--1".2(;--' - -I--:-(;-J
_._.. _.__. __.•._-_.. _.__._._- _ ... _-
·"---?:'Io' .... ··. --..'". ·j:fij~r--·-· . ·. ······. ·:r-.1'.1 "'. _- ·---T7?---
Hox h. cx, FlclIl,j
v .n
J)ungtlU (Iicri! icr;, syl \' ;tl ic ~ Vi(];il)
7.20
----- - '17."10-- ---6.18'
I5fS()KYium:~p.
Ipil l lntsia bijugll
--~- I --·-,~~--6.~!:I 2.38
.. -. - - --.- -.-- ..-----.. ---.----- - ...- ..----.-- .--.--'C2.00
IO.W
3.R6
4.10
1.49
1.25
.---
3.16
27.09
7.t14
25.04
7.74
8.54
6.t11}
3.00
IS.65
22.00
fJ .JO
6 .1:16
-1.82
2.19
1J.75
11.23
O . K t1.e J
Kanl1lgollg ( Diospyrtls d iscolor Willd.) Kumagong po nce (Oiospyros poucci Mcrr.) KaI1110rl -bay.tni (Oil!cn hl
21. 17
r---~
7.56
II1cgalanthli Men.) Kawn g· lakih an
8,22
45 1
6.69
3A2
'---'-rYJ- -'
3.98
2. 1J 1.90
'- '1 2.22
53"
4.06
1.87
3.94
4.29
3.0 1
1.37
. .... 4.7:\
4.04
2.K2
1. 33
2.1 4
1.19
4.114
_- --
- 5.14,-c-- --'-.'-i- .-
(D y~()); )'I \J III ~'r}'l(JhOlryum
1-::~-c 1 i" q'L)______ Lithl)(;.lfTIlIS sp. -~
~52-- '-g{~T'-
-T..iJJCkii ::Udcki":l- hcrnardt:;;-- ... '"-"24~)O--" ~·7M-·
- -'-TA9~-' ---JI:57- ----~5.0i·--
---"-7,Jr' ...--, ---~~Ts-- ~-
-Ts .18
I_. ~=~_I __~,~_ ---0.9) 3.9.1 2.4<)
4.65
(Mcrr.) Rids d.J
-_.-
,1":24
- --_ ..4.6 1
2.61
1.60
3.38
1.54
Malakaunon IDil!c nia luw lliensis (Vidal) Martelli cx Our. CI Jacks. l .
23.60
).40 -
7.37
SAO
2 A6
14,75
4.63
Malapan au (Diptcrocarpu~ kcrri i Kin ' J Manggis IKoompassia
17 .26
6.86
6. 12
2.09
1.10
10 .79
4 .29
3.83
1.3 1
1.07
24 .96
8.94
9 .0?
3.79
2.2 7
IS~(~
5.59
5.(IR
2.37
1.4 2
cxccl sa (nccc.) Taub.) M,mi\.:u ik (Palaquiurtl
18.6 1
6.30
6 .94
2,18
2.21
11.6 3
3.94
4.34
1.J6
1.4 2
IcnuipetiolalUtll Mcrr.J
Pi:mg;t !GOI l1 ua \)hU\,;lli (oli,l (MaL) A ~~c lll i
20.60
6. I R
7.0 1
3.79
2.24
11 _88
3.86
4.1R
2.37
1.40
17.10
6.36
5.99
2.80
2. J5
10.69
3.98
3.75
1.75
1.34
6 .05
6.)8
7m
5~7i, -
18.27
HS~"~k.~·"~(~T""~"~'i~"~
Prc~ l.) I Lil !l\lt'iHP U-;, __=+-.=co+-~~-I --o·o,·U l'li;lll S lI;lnmii 17.67 5.55 .-----(, -.,-:.--· --~~-.uS :l 21 ... - -,I.().1o-I-~=-·I-~A 7 "4-.1-.1--(A. n C.)
l~c h d . 1
HT~"ili~";J~i.~,~"~h~a\~(~T~~~'-"~'i-".~"·~i'-'--I-,)o,~",~.,-I-~).'.17.,- ---(1:~-- ---2.R,~ - - ---~ --1.1 .62
rl ...~ li d i s~ i lll; 1 Gtirf. )
TIlIl!! !I >":l": f:' i ;j!l l hu ~
~)- -
(1.:'1.1---
qu;,;tria latu s (/'.·k rcl MI".e'll.-!.-.=c.--I-~c; Y ;II.;;II Lllio; 11101'0;;1 2."\.96 :-:.2:'1-'-
~~~;,(tl hl,,\\'.l B. l.esser·KnowJl
-+---.+--- --
__
Sp,,:,· i..:~
----t;.':p;-··-
-·-:~.7,1
------:!:o.l-
~JI ·-
"'···"·-)-.il~·
H!I~"~1i7k~hi~k~;!t~'~(,~),",~.p~,,~,,-,----- 2 4.82
-~-
-'-.,-8· ·
--:I:5"f"-- ··--uci"----- '-" '-~:;:,--- ~--,i":"im---
-
T.Ir-···- -'-- iJl'
1.27
_~ ---7.62 ----:t.~ -~1·.7.5o , -I-7.I7."~.9~"-I-···~ -~,-'- "~I (l ~ ____....___. ______ -.----i- - - - I-----I--- -
·1j;' la~;I'iZl~.iri~~~I;J;ln;li- - ! 6.Hi)- --4~K7-- --X-.iiT- --TiJr-- - -2~.~17~+-~lcO~55 ---,1~O:-;-- ---~-- ---(Blall t"l ) Me lT.t
-
-'-'rc;i- '- --~-
2.0S-- -~. -
I.SX
1.36
4.)\'1---- ----:r-7(~--- ---f.~ ~
IUlig irlllin (Il lume) I ';l.~ 8.: K
~:;::~:::}I\Sal1;li Gmup
_._- -
--'4!N- · -5~~)··- --" -_..,,---:--_.--- --J.~- -2:14~ --9."14-' --~~ .---.-.-:...._..._ ... ---··--I .-:i}---·I.34""
_(N c (ll1:n~~.!.~:!!..;:.rU______ _..___ ----------' _ _ _
.
__.___.__.._____._.___... _ ..~ "
._._ .. _.. __ _
.....
CHAPTEfl6 . Wood
'¥'RiIJingag l!I~rt'ad()i
(c~u;;-;-;;;mi-;;-;~""'--¥
······iTiiy··· ". Tii:l" .. ----:fiT---. ---T;hr-'- 122
Vid.j
"-Ki lp(l l as;u'i{NtprlCri~~-'---""-
(;.1 1
'--U;:)(j--'
fl .·1 7
1Ill!l3bile Bluml') 1":lIIgillAlhil.ia khh~k 0 .. ) .. -n~ ~.- --~- ··----:<;j2- -
"--T7"H-
-'-i4.~
4 .16
2.)0
'--1.-,-,-'
).20
--J:j4
Ikn lh .1
P;llangis IM
2.23
4.6!
,.-;-;:;r .63
. '~
plcrt}(;
H·I~·.~m~"~)"~"~m-(~rS"·'~"-"~"'~"-)S~i;t---I-·)"O.·575- -7:4:·T··-· --16:-f~--' ~~ ---:u-2 J"i.J.09-I-'4.'675-1--~(',.")6;--+-
-L~~:;i~~~~~:c~()lrcJ. --17:0.';"- --5.39- ---~·5.(;(I- -- ----J.lJ2··-- -2."f:f""~ -10.66 --- ).3~ --3."54- ---',--;;;;---+,,,",1 1.)) 1.89 "(~B~',~"=,o~R~"d~ik~J~~___~'_'____ I_______
.. C. Planlatio n Species
AC:lcia erassicafTl:l A. Cunn. ex BClllh Acacia cincinrl;l(a
20JJR
Banaba /l...agcrslrocmi;l spec io'~'j (L) PeTs.) Ipil .ipil, Giani /!...cut·acri:"jh:occx~cphala (Lam.) de wit)
16.72
6.7H
15.25
S.ll
2.M
2.1}1
12.5 5
4.24
1.65
3.32
1.27
1.42 9.53 4JJ4 1.86 2.2H 3.61 --<5~3u6--+---'5<.~,---j----').-;;8"----I-",,--t~""«-t-"""__i--""n-+--o,,:__-i-,:;;_1.42 2.27 lOA5 :'1.70 2.3H 3.35
---j534
-"~(4J~
.'i .50
hl"J1~.~M~'~d~iu~u~'''S~"~,,-,g~,,,,--'+----I---Group
._._----
_________ I _ ______----1
I-'A~.C""·":::: nm=,,,=.;,,07Sp::-:,,~;,c,-I---
).20
'''-'130-
-- 9.71
2.00
3.44
3.40
1.56
--------i-------j-- -4----1--~-----~---~·---
..- ._-.- .-.-.----- ---·----j---j--- I - - - j - · -- ------1- --1
··.. Apilong (DiplcTocarpus -..- 17.6:' .~ -""8.01" - ··-···-(;:2"(;·--·····- ~r--- --2.00---1·--"c,~.o~S-I--;S...o"grandinorus Blanco) .__ ~__ Apilong,i3asilan ---_. - Tlf.i6- 7~- 5 . H7"- ---·1.9)~·-··· ! -~- 11.4!- 4.76 (Diplerocarpus curYflchu s Mio.) Api!ong Bfa:ld.wi ngcti 16.57 6.76 5.51 10.36 4 .23 1.59
1--'--3.9)-"
1.5 I
1.25
,_ 3.67-~---J:2i J1}4
1.90
).44
1.19
1.00
300
0.99
0.86
(Oiplerocarpus kunsllc ri
King) Bilaog (Calophy!lurn inophyllum L )
111 ./6
6.3U
4.SU
8.85
1.59
1.94
HD2,=go"n~g'7(7A':'";C'SO!::'C;'''::':-'""::,,,,,: -1--'''4,,.9wgc-I-"c5'.'84"---· --5.24 - - --~- --;-1.76)"~-"9.')(;-'-1-~3'.6"5'--+-~)'.'''8;--f--"'.6"--11--'1."0,,--1 Fox w.)
""""H:igakliak'(6ip'icrocarP'1s \"llidus Blume) Kal llll1pil (Tcnnilmli-;;--'" mic,ocarpa Deene.) K:llmon (Dillcnia philippinensis Rolfe)
..... 4.60
1&.38
5. 16
3.32
(lAO
).79
2.28
I 1.48
3.22
4.00
_._--_.._---2.08 1.54 2.37
1.42
r1KFu~I;7,g~.ib'~b~u?;(~D~)= ,o~,~y~h~ " ,~,-I--~'4'.4«9,-1---5<.~7''-~----' S .'7),---·t-·--~'~.6~,----I--;L-7;;6c-+-"C9'.06",-I--'3~.5'7c--I---'3~.5~8c---r---'l.no,,---1--~
1"",'~'~ 'cl~,u~"='~D~lu~"~"~)~~----j-"~'-l--,",---j Kuling-manuk IAglaia 18.42 5.25 1--~7".""S8;--j--·)-'.O"'8-·- -~2;C.O;;;6,--1--;,<,<.5"-I-'3'.2;;;8- i - -'4'.7"'4 ---.1----.0;----+--,"'--1 1.92 ].29 luzoniensis (Vid.) Merr & I~olrtl
1....1miolDracOfltornelon
15.68
4.36
4.77
1.83
1.58
9.80
2.72
2.98
1.14
0.99
~c~d~u~Io~(~D~r"~"2'~U)~S~kS·'2'~I'~I----I--·".,,--I·--'07--+---~7T---1----",----I"---+--",---I----",----j----,-,,,--1..1nirau (Tcnllinalia 15.63 5.94 6. 11 1.84 '--rTR-- ·-9~77 3.71 3.82 1.15 ~ ~'~·o ~p~c'="~'d~;~;=E~'''~'·f):c:,------·ILokinai lDacrydjum'~
-~
----"'----j----,~,_--1--,"'--II--oc"'--li ---.,"'3.65 2.09 1.70 9.65 2.10 --
IJeccarij Pari .)
H,-" ":·=",,,=g7.(P';'="::";:-h':::""lia::---+"'9;-.;-,),- I--.'
2.28
1.31
1.06
-2.09- 1-''''<.9''6-1-~3;-.'17''--· -- 3.52-- I----'2.n9~'- -I- 'I.,),,--i
~ct.1b i lis
Mere) Magabuyo (Celtis luzonicil
- -)-. '-6 -- - ----;" .3"2--·- - '-.-IJ-'-
Warb.)
"""'N7a~w""'V~;'~"-"~';~'~rP~o-"~"-n~,,---·I-C,76-;.)~4--1--,cS.·();~6 -1- - ·S'.5 '·'-·--- -'-'~27ii)-- -2:06' --'T5~ --"~."7:--+ --;;,'.4'8- -vilJallli!ii (Merr) BachniJ Philippine mapic (Ater
15.77
laurinum liassk. :'IpuJ Boe ven & de Vriese) Piling,liilan (CallariuUl
'5.89
4.66
5.41
2.09
2.08
9.93
2.9 1
IU7.0niconl (Blume) A.
Gray ]
NaHonal Structura l Code of the Philippines 6'" Edilion Volum e 1
338
<'-;.6'2--I-;1~
13 1
130
G·l2
C HAP TEr, f; . Wood
T;Ulgik'I Sh ()J'~a - -!loly~peml:l (1I1:ul("o)
15.&3
MelT.1 Il .
-·-5J1)"----- - - I"1V '--
6 .2)
~~ -'"¥i).X(j---
_._-
.-- - ...
Lc.~scr-Klll1wl1 Spct'il'~
'-"-rK~
--_. -" - :i A·1-- _.. .. ...... -1:"i2" "'--" ,
- - --
.. --•.'--"- A,;;;;lg (DiosPY7c;s--- - - -l5.iiR - 5:1(; ...- ._-_.-.-._- - --f3S---' --_ [ ,R6 - '--''7i:(Tf-3.2.1 JI}Trhocarp 3 Mjq.) -- _ .. _--- .._,-,-- -- 10 .54 - - -'4.(j-, AIIlll 1l3 1 (O"'phciI 6.34
16.86
6.42
n .I O
6.4 8
16.24
6.60
1.75
2.14
....£.~.!!!i!~£0I1a Vi~_____.__
Apani! !Maslillia pCJ]landra Blume ssp. philippincnsis
_
- - '5',-'2-
- .- - 1.69 ... ..
1.65
- iTi:fiiJ -
2.4 3
1.60
' lUI
~-:i'm---
---2 .02--
1.63
l.51
-,
-'--"Ilj~-
.------- ----.~"- - -
- -"
:l.20··--~
I
I
20.60
557
-.----s.!5-. '-- --1iJi--'-
1031
4 .67
.
__ ...2.55
:1 .48
'1.13
.--- ; . ~
.
1..14
---,-_.1.06 __.. _ ---.
.-
(WlIlIj!.) M all .) ,
O:lIukanal: IChisochclOJl cu mingianu.<; (C. DC.) Hamls ] Danai-banai IRlidenllile-hem ....Jti.nnal
----- -
...- ''".. -. ..• ,,-.. -j A(j--" -'"
---:'.96 ---
12.Rif-- ·~-"J . 22 "---'-"4.3:-1 --- ...-
-··--~ · 1.92
2.92
-2.()4
12 .82
;;3.56
43D
'-'-'
0.90- -
5.36
7.26
1.85
1.44
11.2t!
3.35
4.54
1.1 6
13.92
4.85
4.74
1.67
1.62
g.7()
3.0.3
2.96
1.05
17.8 5'
5.36
6 .30
2.24
2.00
II .J6
3.35--
:1.9:)
1.4(}
' 6.08
5 .7 1
.-:uo-
13 .37
5.7 1
2.05
557
2.14
----. '-'-i~:26'-
1.27
18.04
···--TO.05 .-
·-'-.0-'-..-0;--
1. 25
--357"" ---YJi:""--- .--- "" "1.71"---
8.36
2.94
1.86
10 .45
3.40
~iS
.__..•••,..".--- ---Ui--
._-
1.8{)-
I.en
J.59
6.88
lJ.i9
. -- ~ -
0.94
5.70
--- -2.8.3
--I.Qij--
1.02
20.51
.-.-~-
- --T !(;-"¥
iTx)-
1.52
--
6.44
-'-(J,)-(;'-~
3.57
Rosh.)
Nato jPaJaquiunl luzon iense (P. Viii.) V.i.~. __ Pagsahingin·bulog (Canarium a~pclUm Bentb) Panang (paJaquium sp.) Philippinc chestnu t [Castanopsis philipincnsis (llI:lnr:n) Virl j Sagimsim ISYl.giunl brevislylum (cn. Rob.) Mcn.] Snntiki fClcidion spiciOorum (DUIli. E)
16 .72
5.45
6.66
16 .SR 14.44
5 .48
14.02
4.98
-
16.87 "-'15~7T" -
._•.-
-----;us--
1.64
1.86
10.36
2.59
2m
9 .03
4.90
2.34
1.75
8.76
2.0)
10 .54
2.21
_.-_.-_.
~--
1.16
3.52
[.02
._---. --TT6
1.62
1.25
3.06
1.46
1.09
~
5.63
4.03
1.34
JA8
- .....--.
3.' 8
9.83
4 .16 3.42
"-:fT'!-
I.:m
252
- --_. _.- ---"'-- 1.91;._---2.66 2.80
1.27
_ _. ..
MClr. )
Syzgium sp.
12 .05
4 .21
Tall -ag (KJeinhovia hosp;",
1534
4A 8
18.81
5.09
5.95"'
1.89
1.78
7.S3
2.63
2.47
l.91
- 919-
2.80
4.5 1
2 .63
1 1.76
3.'8
1.18
-_..3.12 _-- - - - 1.55---
1.12
'- 1:20
L)
Ui!lian (Lilhocarpus celebicu$ (Miq .) Rehd. ) Usuang-saha (Endiandra laK.iOora MelT.) TemSlIocmia sp.
15.49
5.39
4.99
2.8 1
1.80
9.68
3.37
3. 12
19.51
5 .32
6.9-1
2.65
2 .1 2
12.20
3 .33
4 .34
-
C Plantation Specics AC;"lcia mangiulll Wi!ld.
15.51
Nancka (Artocarpus hctcrophyllu s Larnk.) River red gum (Eucalyptus camalduJcnsis Dchnh.) Teak (Tee-lOna grandis U .)
20.55
...
.- ~ -
16.2 2
18.94
.
5.60
7.36
2A9
5.26
7.1H
2.04
--z:]4-
- - --
1 .49
-
-- - --
1.9 ' --~ 1.92 1.51
4.99
4.93
2.8 1
2.01
6.14
5.48
1.63
1.4 1
-
IV . Moderately Low Group A. Commercial Species
_ .. 3.50
12.85 10 .14
3.29
-
-1 .',0
3.84 3.08
9.57- -3.83
3.43
2.82
1.64
1.76
1.1 2
1.66
J.J3
--l.~~·-
4.60
3.1 2
II JN
-
1.22
1.27
1.20
---2:'18
0.94
1.76
1.26
1.02
0.88
2.62
1.17
-
---- ._ - -- - ----- ----- - --- --_.
S trcng~ 1
Almon (Shorea almon Foxw.) Anubing (Artocarpus ovatU$ Blanco)
15.3 2 19 .46
4.04
5.34
4.19
1.87
12 .17
2.53
Association of Structu ral Engineers of tile Philippines
3.34
-
CHAPTEri G . Wood
'Ti~~'ik;;i;og{T;!;~-;;~;~:;;'~;~~ Mnr.)
G 13
'J:fu' --. '1."i6
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···---··-4,("j--_U- ----
1.21
'-'13X--' -7.~'- ---2:10- -----27JO-·-'f----~O~.7~5--+-cO~g~6~1 .... ..
~·\;;;illd. Forma'
-~
Manggasinorong-!akihan
14.44
(Shore,] vircsccns Pari's) MayJpis !Shorca paloslipis (Blanco) Men.)
14.60
~
~--:--
- - . ---
---:--.
1.45
J.29
5.81
-;;1'~,g~"~:ri~o~g,;''':C,;(O('~':!~'a"o~,~y;;",~o"--I·-"··I5.~
--4:76'
(j,05
2.32
9.86
2.06
2.97
3.78
sUIlL,t'ranUI11 (Jack) Blume
ssp. sum,1IranuJ\l Robs.), Tuai (Bischofia j,lVanica Blume) Shorea sp.
4. J 4-- 1--"'.67,,---1--4""."10"- 1-';;.8"'O"'-""2;C2;-+-';2'.5c;;,--I-~2;;.9",--1--2".c56,---1-"C".,"3;-1
14.75 .
13.92 -
---:fsr'- -------4':-2'(;----
-"- ---n};'l
1,15
oB-.i,~·=s;;sc='~.Kv,~>o~w~"::cS~p'='''.ie='~.--1----- .-....--~ 1-·----+--·Anongo (Turpinia ovalifolia Elm.)
1l.70
3.68
'-"-'~f78-~
Balakat-guhHI [Sapiurn iUl.Onicunl (Vid.) Mcrr.J
1.30
l.38
1.55
,:CO-.
11~32~ -'3~8j
I3aJal;(i [J-lornalanlhus populncus (GeiseL) Pax
1.'14
1.65
------:fO]
lUO
2,66
0,65
. 0.72
2.36
O.<.X}
0.8l
0.86
0.97
1.03
0.82
------ _...__._.. ~.-.--- ~-----+-.--I 7.31
1.31
2.30
7.07
2.39
~~~"~.~N~P"~"~"C~"~'~J~~~~+-.,,",_+_co~·_ Eakle (Ficus ba!clc MCfT.) J 3,84 ~·----1~-~,,-·+-c17'"2c- -8~65'"
3,25-- --~.~.-
---cl.c44c----j--I'.O'"g;-
',.;--+---,;,.7.02".-+~'''O.'37c-i~~2''.9cc4c--j-~~~~I-~I~95-·-I·~
16.59
0.94
Himbabao {Brou$$onctia Jumnica (Blanco) Bur. var.
-- Q ] 5
0.87
0.83
1.20
0.86
12.83
404
4.45
2.24
2.00
8.02
2.53
2.78
! .40
1.25
14.49
3.56
4.26
LSI
J.32
9.06
2.23
2.66
0.95
083
luwnicaj
Katong-malsin
(Chisochclon pcntandrus (Blanco) Mcrr.] T it o''ni'-''----I-,,,,·,.''',,- -3~ philippincilsis (Braid.) Gordonia sp.) ·-;;C~ .. 7-p~,,~,,~,"':-,;~,~,,~S~p~ccC';~,,~'---t----I~.-..-
-----.--...- . -----1--
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dcglupt3 Blume) Durian (Durio zibcthinus--
I 3.881--'''".''90;;--I--c5,.;c'5'-+--;':>8~()---
MelT.) Para-rubber (lkvca brasiliensis (HBK) Mucll·
J
~;~;~l {Sandoricum
LJ3
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. 3.9 I
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~2-.9-1·-·--· --3.62---- ·-·-~'-.44·~ ~T
-7.40---
LCk",ocCC"",jj"=p",,(B,,",,-',,"',,.~f.)"',"n"OIT,,.,-J_ ' -_ _.______.L_ _ _ _-'-_ _ _ _--'_ _ _.L____
th
J.37
1.05
~-1.-8f-- --'--2-.2-6- ~~O-.9-0 -~ -0-.8-2-- I' _. ___ ._ _ _ ._. _ _ _ _ _ _ _ _ _ _ _'-~
National Structural Code of the Philippines 6 Edition Vo}urne 1
6·74
CHAI'TEH 6 . Wood
'~V ".'I~.o~"~''' S~".~ "~ ,.,,,tI~,7G''m~"~,,'--'----'----'--·-·-·--
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. --i)Ag~
subumurans (Hassk) MClT.] Tra~mg (Shore:l uvma f)ycr-- ~-I1:5(;
ex Brandis) TalulO IPlcrocymbium
f--7';~"~'~'''~d=",,''~'(~B~'~ar="~o~)":M~'::"~·['-j----j----+------I- ___ 0_,_ .. _~~ _________ ._....___ .___ ..______.....•.. , .___ .. __ .. _. ______,___..._ n. Lesser-Known Species
I-:A~n-'~b~;o-lI~g~r~r-"-n-"-on--,-·,-,,7,,..,;-,+-5~.75,7,--l---;2~.3;;6C:-+-'2-:;.47.6--II--·",.0"'-- - I j n - -,-,-,-- '---T'{-, -
H~"~"c'~~"'-"n7g7"--;('CM""'j;-,---.- --"-13-i-- --,-.,-(;- ----')ii-
---1.-5' -
--I.~-·---- ---"1":-72-- -"6.45 "-- 2~ '----D2---· -----0-.9-' - --- --TOs·-
azedarltch L)
-~ -~-
6 .07
2. 15
Oinuang (Oclomclcs
9 .09
3.66
~!'_,
WaiL)
3.11
0.74
0.88
2.29
5.68
1.94
0.47
sumal(ana MiQ.)
t
n .5S
I
D'.a IAlsl()llia scholaris
•. 64
J.9 1
It Dr. var. scholarisis)
10.14
).42
KaitanlL {Zanthoxylum
11.37
4.36
05.';
O.f1O
2.90
1.20
-:-
H I!
U4
0 .86
6.33
2.1'1
~AO
0 .96
1.29
7.10
(1..)
limonclla (OCI11151.) Alston )
Tallgisanr,-bay.\wak (Ficus··+--c;c;c,+-",.--j-------4.32 J .56 varicgma Illume Vilr. varicsa~ .. _ ._ __._ ._____ C. p J:mtation Species
-"--0:&1'-
-~ ----rC>l7-
--
034~ ~ i
i
--~~-
-i}'54'-j
-----o:c;,-- -"()JjJi
--{}:7!i-- -----------" (j!ir - ----:--- ._--O::W---2.70
0-:49-1I
+---+---+------ ___..__.. .._ .______. _. ________ .._____________ ,,[i
Alnussp. 9.66 2.53 2.81 1.78·--I-~I--,,,'.04"·-j--7'175';;---j--. - . T:;~1.11 hB~';:IS~""(=·,~ Oc "o:c':n;:c' :- - - ---1-o,'.,"'''-+---c;2.'no;---j---,-,.'6,.,-'----1----;".1"'0- --1---+-;c5'.4'8 _. - -----""."1- +- -'2'.2"'--1---;'''1.8"'1. -..---
~~"'' :>:"'' '",m,,,;d,,',,',,(\,:C,,' ' ,,'':)':-"U':'(c:>.J'c:--j_~,.,.---+_;-,-".+___ Bayabas (Psidiulll guajava L.) Ilans· ilnng ICananga odorata (Lmll.) Hook f. &
12.55
2.68
1.13"'1
----1
_ --+_. ___-j_ __+---,=-!__"",-j---- - - -......_._______._ 1.68
7.84
- ---1---+--1------------1-- ---/--
-Illoms.}
Gubas (Endm:pemlUnl pe ll ll UHIl Mr:rT I KaalO
9 .66
2.96
3.74
2.36
1.02
6.().1
1.1:15
2..14
1.48
0 .64
J 1.08
2.77
:UO
1.40
1.J3
6 .93
1.7.1
2.(X)
0 .88
0 .83
01>3 -
2.67--
I-+.K","po"i,"[SC"'-''':;b'',''"'','"'''',,'',d''',,L..--1I ---;.'.2,,,--I-'''1.'-''35~-I--TW- --·-o.-:~
1-T(1 ~"~)rG,,3'~"~"~'[~C7c---+---;,"-+---c;,"-I----77 __-+--~",,-~-,,"oo"Lumbang IAlcuri(cs 6.39 2.47 1.63 0.71 0.88 '-4.00 Illoluccana (L.) Willd.j
Malapapaya IPolyscias nodosa (Blullle) Seem]
-.-I-="'--+-"";-__j----;-=----0.9" 10.92 4.04 5.25
------0:&4-- - -W- - - -0.46- --- ----0.39'~5--'-
---- i.oz- - --.~-----. {).55
_J
.--,'.",,-I-"'7=-II-cc;,-,;---I- -I- -;c.,-.,--+--;c=1 6.82 2.53 ~.28 0.61 0.73
I--'iM 7o",",,",::,"n":;a""= ==--I-,,,O=.i..;;- --3-.8-'- - -4 -.-2(;-'- --".·'II..---+-"~.2",--lI---;6-.""'2-+---c;2.--;42,,-+--'2;-.6"6~-I--"0".'''0--1-'0''.'''''--'' [Par8serianmcs ralcataria (L.) Nielse n]
~s':p"::'":;;"ish'-"::,"id":ar"(rCc::,d:;:,:c";::,---j!--";0".9"4.---1--;-".6"'- -!--'4'.2"2--+---"'.3"'- -!--"'.2"0-- -"(rS4-- --""'2'.276 -+--"'2'.64"--+-'0"80'2,-----1 '0'.,"54 oooTlua L.)c;I;)-(Spa!hodca c:::==-j-,.-;;;c-+~=-I-......,,,,--+----;;--; Tulip, Afri 6.OG 1.63 2.3.1 o.8T~-· -----;;M--I-c;c;;;-+-;-=-I-.....,c:;-;~ 0.98 3.79 1m 1.46 - ---0.53--'--""-'0-:6] C311lpanutata I3cau v.) '--""=,-""'-=:.L.._J. _ _-'-_--'_ _ _ L ___ ______.__-'--_ _,_
______ ._. __ .. __ ._ _ _ _ _ .. <--.__.
Ass,ociation of Structural Engineers of ([le rOlJilippine s
NSCP C101-10
Chapter 7 MASONRY NATIONAL STRUCTURAL CODE OF THE PHILIPPINES VOLUME I BUILDINGS, TOWERS AND OTHER VERTICAL STRUCTURES SIXTH EDITION
Association of Structural Engineers of the Philippines Suite 713. Future Point Plaza Condominium I 112 Panal' Ave nu e. Quezon City. Philippines 1100 Tel. No : (+632) 410-0483 Fax No.: (+632) 411-8606 Email: ascponlincUi)glnai l.colll WeiJsilc: htlp:llwww.ascponline.org
H1
National Structural Code of the Philippines 6 Edition Volume 1
CHAP1T.I~
7 . MW;Oilfy
"l 1
Table of Contents CHAI'TER 7 - MASONRY ...................................................................................................................................................... 4 SECTION 7() 1 - GENERA L ......................................................................... ..
d .... ....................... " " " " ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' .....................
4
... 4 . .. 4
70 1.1 Scope. . .................................... .. .. .. . 701. 2 Design Me thod s ...................................... .................. ....... .. 701.3 Defi niti ons ........................................................... .. 701.4 No tatio ns ..... ............................................... ...... .
.. ...... 4 .)
SECTION 702 - MATERIAL STANDARDS ............................................. ~ ........................................................................... 7
.. 7
702. 1 Quality........ . .......................................... .. .. .. 702.2 Standards of Quality................. . ................ ..
..... 7
SECTION 703 - MORTAR AND GROUT ............................................................................................................... " .......... M 703. 1 General .. . 703.2 Materi als .. . 703.3 Monar .. .. 703.4 Gro ut ................... .. 703.5 Additives and Admixlllres .................... .............. .. .
................ 9 .. ...... 9 .. ..... 9 ...... .. 9 . ......... 9
SECTION 704 - CONSTRUC'nON ..................................................................... ,.................................................................. 9 704.1 704.2 704.3 704.4 704 .5
.... 10 .10 ...... 10 10 . .. 10
Gener,,1 M ateria ls: Handling, Storage and Preparation Placing Masonry Units .. Reinforcement Placing ................. .. Grou ted Masonry ................................... ..
SECTION 705 - QUALITY ASSURANCE .......................................................................................................................... 12 12 .12 12 .. ......... 14 .. 14 14
705. 1 General ................... ..... . .. .............................. .. 705 .2 Scope ...... 705.3 Co mpl ia nce wit hf'm .. .. ....................................................... . 705.4 MOt1ar Test ing ............... . 705.5 Grou t Testin g ........ ........................ ... .. .. ............ . 705.6 Recycl t1 Aggrega tes ....... .................. .. .
7
SECTION 706 - GENEHAL DESIGN REQUIREMENTS ................................................................................................. 14 706.1 General . ................... ................ .............. .................... .............. .. ................ ..... .. ......... .. .... 14 706.2 Allowable Stress Design and Strength Design Requirements for Unreinforccd and Reinforced Maso nry ... ......... ......... 17 706.3 Altemative Strength Design (ASD) and Strength Des ign Reqn irements for Reinforced Masonry ...................... .......... 19 SECTION 707 - ALLOWABLE STRESS DESIGN (ASD) OF MASONRY ..................................................................... 21 ..... 21 ..22 ....... 26
707.1 General ............ ................... .. 707.2 Des ign of Reinforced Masonry .............. ............................... .. . 707.3 Design of Unrei n forced Masonry .. .
SECTION 708 - STRENGTH DESIGN OF MASONRY .................................................................................................... 27 ..... 27 . ................ ................................... 29
708. 1Genem l .... 708.2 Re inl()rced Maso nry ............................. .
SECTION 709 - SEISMIC DESIGN ...................................................... ................................................................................ 37 ..... 38 .. 38 ." 38 .. 38 . ... 38
709.1 Scope .. 709.2 Gene ral ............. .. 709.3 Seismi c PerforJ1lance Category A. .. ...... ...... ... . 709.4 Seismic Performance Category B .... .............. . 709.5 Seismic Performance Category C ..
th
National Structural Code of the Philippines 6 Edition Volume 1
7·2
CHIII' TU1 7· Masun,y
709.6 Se ismic Performance Ca legory D .. 709.7 Seis mi c Performance Category E ..
.. .... 39 . ·· · · ........ 40
SECTION 710 - EMPIRICAL DESIGN Of MASONRY ................................................................................................... 40 710. 1 I·leight.. .... ............. ........ ........ 710.2 Latera l Stability........ ................... .... ... 71003 Co mpressive Stresses.. .. ... ".. ............. 7 J 0.5 Minimum Thickness ..................... .. .. ..... ............ .. .. ............................... 710.6 Bond.. .......... ...................... ............ ......... ... .. .............. ........ 710.7 AnChorage ............................... ............... .............. .... 7 J 0 .8 Unburned Clay Masonry .\.; 710.9 Stone Masonry..................... ................... . ................ ......... ...... ..
.. .................. . .40 .. ............... ..... .40 . ...... .40 ........................ 4 J .. ............ .41 .. .... 42 .............. .42 .. ...... .42
SECTION 711 .. GLASS MASONRy ................................................................................................................................... .. 43 71 1. 1 Genem l ...................................... . 7 11 .2 Mortar Joints ....................... . 7 11 .3 Lateral Support ................. . 7 J 1.4 Reinforce ment ............... . 7 11. 5 Size of Panels .... . 711 .6 Expansion l oints .................. . 711 .7 Rellse of Units ............................... ........................ .
. ........... ..... . 43 .. .................... 43 .. .... .......... ....... 43 ..43 . .. 43 ..43 ...... 44
SECTION 712 - MASONRY FIREPLACES .................................................................................. ....................................•. 44 7 12.1 Definition ................................. ........... ....... ........ .. 7 12.2 Footings and Foundations.. . ........ ........ . 7 12.3 Seismic Reinforcing.. ......... ...... . 712.4 Seis mi c Anchorage. .. ................. . 712.5 Firebox Walls .................. . 712.6 Firebox Dimensions 712.7 Lint el and Throal. .... ............. . 712.8 Smoke C hamber Wall s ................................................................................ .. 7 12.9 Hearth and Hearth Exten sio n 7 12. 10 Hearth EXlcnsion Djmcnsions........ .................... . ... ................... . 7 12. 11 Fireplace Cleara nce..... ........ ..... .................. .. .......................................... . 7 12.12 Fireplace Fireblocking ... ...... ...... . ................... . ................... . 7 12. 13 Exterior Ai!'... ... ....................... .. ................................ .
......... ... .. ..... ... ....... .......... ............ .44 ................... .4,1 .. ............. 4,; .. ............... .. 45 ........... 4S ............ ......... 4 5 .. ....... 4 ~i .. .................. 45 ......................... .45 .. ............ ... ................ ... .46 .. ................ .46 .. ..................... .46 ................... ,,46
SECTION 713 .. MASONRY CHIMNEyS ............................................................................................................................ 47 . .................... ........ ..................... ...................... 47 713.1 Defini tion ......................................... ................. ........................... .. . ....................... .... ... .................................... 47 713. 2 Footings and Foundations ................ ...... .. .................................. .. .. 713.3 Seismic Reinforcing ........................... .......... ..... ................. .. .. ......... ... ... ........ ............ ......... ....... .41 . ............. .41, 713.4 Seismi c Anchorage ......................... ............ " ........... .. .......... .48 713 .5 Corbeling. ..................................... ...... ......... ...... . 713.6 Changes in Dimension ..4 1: .................. ............... . ...4 ;: 713.7 Offsets.. .............. ...... . 713.8 Additional Load .............. . . .......... .4 0 7 13 .9 Temlinati on........ .................... ... .. . ............................ ................. . . .. ..48 7 13. 10 Wa lllllickness ................ .............. ........................ ............. .. ............... .48 7 13. 11 Hue Li ning (Matelial )................. ...................... .............. .. ......................... ........... .48 7 13. 12 Clay Flue Lining (lnslall ation) ....... ................. .. ................................. .. .................................. 50 7 13 .13 Addi ti onal Requi rements ... . ............... ..... ........... . ........................... .................... .. .. ..... .... 50 713. 14 Multipl e Flues.................... ..... ... .. ................. .. .................................. 50 713.15 Flue Arca (Appliance)................... ........ .... ................. ................ ....... ..... .. . ...................... 50 713.16 Flue Area (Masonry Fireplace) .......... .......................................................... .. ... .. .......................... 51 713.17 Inl et .................... .................... ....................... .. .............................. ................... ................ .. ...... ................................. . 713.1 8 Masonry Chimney Cleanout Openings .................................... .
Association of S iru ciural Engineers of the Philippines
CHI\ PlU ~
7 13. 19 C himney Clearances .. .
7 J3.20 Chi miley FircbJocking ..
National Struclural Code of the Philippines 6'" Edition Volume 1
7.
M()~~{Jnry
1
. ..... 51
...... 52
AREA, NET is the gross cross-sectional arc•.! minus (he area o f" ungroulcd <.:orcs, notches, cel ls and wlbeddcd areas.
Net area is th e actual su rface area of cross sec tion of m
701.1 Scope The materials, design, const ruct ion aild quality assur
masonry shall be in accordance with Ihi s chapler.
BOND, ADHESION is the adhesion between masonry and mOl1ar or grout.
units
701.2 Design Methods
Masonry shall co mply with the provisions of one of the following design methods in this chapter as wei! as the
BOND, REINFORCING is the adhesion between steel reinforcement and mOl1ar or grout.
requirements of Sections 701 through 705. BONO BEAM is a horizontal grouted ele ment within masonry in which reinforcemcnt is cmbedded.
701.2.1 Allowable Stress Design Masonry {ksigncd by allowable stress design method shall comply with the provisions of Secti ons 706 and 707.
CELL is a void space having a gross greater than 970 111m 2.
701.2.2 Strength Design
CLEANOUT is an opening to the bott om of a grout space of sufficicnt size and spaci ng (0 allow the removal of debris.
M
comply with the provisions of Sections 706 and 708.
c ross~scc[i() nal
area
COLLAR JOINT is the mortared or grouted space between wythes of masonry.
701.2.3 EmpiricaJDesign Masonry designed by the empiric a l design method shall comply with the provisions of Sections 706.1 and 710.
COLUMN, REINFORCED, is a vertical structural which both the reinforcement and masonry resist compression. member in
701.2.4 Glass Masonr.\"
Glass masonry shall co mpl y with the provisions of Secti on 711.
701.3 Definitions For the purpose of this chapter, certain terms are defined as follows:
COLUMN, UNREIN FORCED, is a vertical structural member whose horizontal dimension measured at right angles to the thickn ess does not exceed three times the thickness.
uni t which is in contacl with mortal' or the surface of
DIMENSIONS, ACTUAL arc the I11ca:-;urcd di mensions of a designated ilem. The aelu.11 dimension shall not vary fro m the specified dimension by more than the amount .l!lowed in the appropriate standard o f quality in Scction
another masonry ullit in the plane: oflh cjoint.
702.
EFFECTIVE AREA OF REINFORCEMENT is the cross-sectional area of rcinforccmcIH muhiplicd by th e
DIMENSIONS, NOMINAL of masonry unirs arc equal to its specified dimcn:-;iolls plus the thickness of the joint with whi ch the unit is laid.
AREA, BEDDED is the
S llrl ~U.; C
of
11
masonry
cosine of the angle between the reinforcement and the
direction for which effective area is to be determined. AREA, GROSS is the lotal cross-sectional area of a specified section.
DIMENSIONS, SPECIFIED are the dimensions speci fi ed for the manufacture or collstmction of masonry, masonry units, joints or any other compo nent of a structure.
Association of Structural Engineers of the Philippines
CHAfY1TH l . Masonry
l,~)
GROUT LIFT is an increment of grout height within the total grout pour.
WALL, BONDED is a masonry wall in which two or more wythes arc bonded to act as a structural uni!.
GROU'J' POUR is the IOtal height of masonry wall to be grouted prior 10 the erection of additional masonry. A grout pour will consist of one or more grout lifts.
WALL, CAVITY is a wall containing continuous air space with a minimum width of 50 mm and a maximum width of 100 mm between wythes which arc tied with metal tics.
GROUTED HOLLOW-UNIT MASONRY is that form of grouted masonry construction in which certain designated cells of hollow units are continuously filled with grout.
WALL TIE is a mechanical metal fastener which connects wythes of masonry to each other or to other materials.
GROUTED MULTl-WYTHE MASONRY is that form of grouted masonry construction in which the space between the wythes is solidly or periodically filled with
grout. JOINT, BED is the joint with or without mortar that is horizontal at the time the masonry units m'e placed.
WEB is an imerior solid portion of a hollow-masonry unit as placed in masonry. WYTHE is the portion of a wall which is one masonry unit in thickness. A collar joint is not considered a wythe. 701.4 Notations
JOINT, HEAD is the joint with or without mortar having a vertical transverse plane. MASONRY UNIT is brick, tile, stone, glass block or concrete block conforming to the requirements specified in Section 702. HOLLOW-MASONRY UNIT is a masonry unit whose net crossHsectional areas (solid area) in any plane parallel to the surface containing cores, cells or deep frogs is Jess than 75 percent of its gross cross-sectional area measured in the same plane. SOLID-MASONRY UNIT is a masonry unit whose net crossHsectional area in any plane parallel to the surface containing the cores or cells is at least 75 percent of the gross cross-sectional area measured in the same plane.
AI'
111m2
A,
A,. A',
MORTARLESS MASONRY SYSTEM is a method of masonry wall construction that eliminates the use of mortar.
PRISM is an assemblage of masonry units and mortar (if present) with or without grout used as a test specimen for determining properties of the masonry.
REINFORCED MASONRY IS that form of masonry constl1lction in which reinforcement acting in conjunction with the masonry is used to resist forces.
SHELL is the outer POI1ioil of a hollow masonry unit as
cross-sectional area of anchor bolt, mm 2 effective area of masonry, mm 2 gross area of wall, 111m2 total area of special horizontal reinforcement through wall frame joint, mn/ ;::: net area of masonry section bounded by wall thickness and length of section in direction of shear force considered, rnm 2 ;::: area of tension (pullout) cone of embedded anchor bolt projected onto surface of masonry, :::: ::: :::: ::::
b,.
placed in masonry. b'
:;;: effective cross-sectional area of reinforcement in column or flexural member, mm? :::: effective area of reinforcement, ::: total cross-sectional area of rectangular tic 2 reinforcement for confined core, mm :::: area of reinforcement required for shear reinforcement perpendicular to longitudinal reinforcement, 111m2 :::: effective cross-sectionaJ area of compression 2 reinforcement in flexural member, mm :::: depth of equivalent rectangular stress block, mm :::: nominal shear strength of anchor bolt, kN ~ allowable tensile force on anchor bolt, kN :;;: nominal tensile strength of mlcilar bolt, kN :::: allowable shear force on anchor boll,kN :::: effective width of rectangular member or width of flange for T and I sections, mm :::: factored shear force supported by anchor bolt, kN :::: computed tensile force on anchor bolt, kN :::: factored tensile force supported by anchor bolt, kN :::: computed shear force on anchor bolt, kN :;;: width of web in T or I section, rnm
National Structural Code of the Philippi,nes 6'" Edition Volume 1
::-: nominal shear strength coefficient as obtained from Table 70R-2
c f)
d
:::: distance from neutral axis (0 extreme fiber, mill :;;; dead loads, or related internal moments and forces :;;; distance from compression face of flexural member to centroid of longitudinal tensile reinforcement, mm
:;;; diameter of reinforcing bar, mm :::: diameter of largest beam longitudinal reinforcing bar passing through, or anchored in a joint, mm == diameter of largest pier longitudinal reinforcing bar passing through a joint, mill E
:;;; load effects of c,u1hquakc, or related internal moments and forces
K
:::: ::::: :;;; ::::
k
F,.
modulus of elasticity of masonry, MPa eccentricity of Puf, mill maximum u!->able compressive strain of masonry loads due (0 weight and pressure of fluids or related moments and forces := allowable average axial compressive stress in columns for centroicially applieci axial load only, MPa :::: allowable llexuraJ compressive stress in members subjected to bending load only, MPa == allowable bearing stress in masonry, MPa :::: allowable stress in reinforcement, MPa :::: allowable compressive stress in column reinforcement, MPa == allowable Ocxural tensile stress in masonry, MPa ;: : : allowable shear stress in masonry, MPa
;;
:::; computed axial compressive stress due to design
j"
J, J,
J,. J, f.·/I
G II
j
axial load, MPa :::; computed flexural stress in extreme fiber due to design bending loads only, MPa ;: : : computed comI)ressive stress due to dead load only, MPa :::; modulus of rupture, MPa = computed stress in reinforcement due to design loads, MPa == computed shear stress due to design load, MPa :::: tensile yield stress of reinforcement, MPa :::; tensile yield stress of horizontal reinforcement, MPa ;: : : specified compressive strength of grout at age of 28 days, MPa == specified cornprcssive strength of masonry at age of 28 days, MPa ;: : : shear modulus of masonry, MPa :::: loads due 10 weight and pressure of soil, waler in soil or ,"Ciated internal moments and forces :::: height of wall between points of support, mm :::: beam depth, mm
L
M,
:::: cross-section a! dimension of grouted Core measured center to center o/" confining reinforcement, mnl :::: pier depth in plane of wall frame, mill == effcctive height of wall or column, mm ::: moment o/" inertia about neutral axis o/" crosssectional area, mm~ == effective moment of inertia, mm'1 :::: gross, cracked momcnt of incl:tia of \'_ ~lll Cross section, Jllm~ == ratio or distance between centroid of flexural compressive forces and centroid of tensile forces of depth, d :::: reinforcemcnt cover or clear spacing, whichever is less, mm :::: ratio of depth of compressive stress in f1exura! member to depth, d ;: : : live loads, or related internal moments and forces == length of wall, mill == length of wall or segment, 111m ::: cmbcdment depth of anchor bolt, mm :::: anchor bolt edgc distance, the least distance measured from edge of masonry to surface of anchor bolt, nUll = required development length of reinforcement, mm == design moment, kN-m :::; maximum moment in member at stage deflection is computed, kN-m ;: : : moment capacity of compression reinforcement in Oexural member about centroid of tensile force, kN--m
= nominal
M" M, M.ICf
M" II
p
P"
cracking moment strength in masonry, kN-m = moment of compressi ve force in masonry about centroid of tensile force in reinforcement, kN-m = nominal moment strength, kN-m = moment of tensile force in reinforcement about ccntroid of compressive force in masonry, kN-111 == service moment at midheight of p~nel, including P!1 effects, kN-m ;::: factored moment, kN-m :::: modular ratio ~ E/E .' m ;: : : design axial load, kN :::: allowable centroidal axial load for reinforced masonry columns, kN
1\ PI
P
II
P"
nominal balanced design axial strength, kN load frol11 tributary floor or roof area, kN nominal axial strength in masonry, kN nominal axial load strength in masonry without nexure, kN ~ factored axial load, kN :::; factored load from tributary floor or roof loads, kN ;: : : :::; = :::
Association of Structural Engineers of the Philippines
CHAP rUi
:::; factored weight of wall tributary (0 section under cOllSidcralioll, kN ::;: weight or wall tribulary 10 section under consideration, kN :::; radius of gyration (based on specified unit dimensions or Tables 7 I I - 1,7 I I -2 and 711-:1), mill ;::; ratio of area of reinforcing bars cut oil to tol<1l area of reinforcing bars at the section. ::::: s-C2tion !~loduILlS, mm 3 :.:: spacing of stirrups or of bent bars in direction parallel to that of main reinforcemcnt, 111m ::;: effects of temperature, creep, shrinkage and diffcrelHial settlement ::;: effective thickness of wythe, wall or column,
r
s s T
Ii
v v"
V, V" W
Ll"
p
p"
JI'm [j
= required strength (0 resist factored loads, or related intcrnalmoments and forccs_ ::;: bond stress pCI' ullit of surface arca of reinforcing bar, MPa :::: IOtal design shear force, kN :;:: 10lal horizontal joint shear, kN ::;: nominal shear strength of masonry, kN :::: nominal shear strength, kN :;:: nominal shear strength of shear reinforcement, kN ::;: required shear strength in masonry, kN ;:;:: wind load, or related internal momcnts in forces ::;: factored distributed lateral load :::: horizontal deneetion at mid height under factored load, mill = deflection due to factored loads, mill :::: ratio of area of flexural tensile reinforcement, A" to area bd ~ reinforcement ratio producing balanced strain conditions ::;: ratio of distributed shear reinforcement on plane perpendicular to plane of AIII \. :::: sum of perimeters of all longilUdinaJ reinforcement, mm
:;: square :;::
root of spccified strength of masonry at
the age of 28 days, MPa strcngth-reduction facLor
SECTION 702 MA'fitful, STANDARDS
1 "/
Reclaimed or previously used masonry units shall mcct the applicable requiremcnts as for new masonry units of the same material for their intended usc. 702.2 Standards of Quality The standards listed below labeled a "UBC Standard" arc also listed in Chapter 35, Part II of UBC, and arc part of this code. The other standards listed below arc recognized standards. See Sections 3503 and 3504 of UBC. 1.
Aggregates ASTM C 144, Aggregates for Masonry Mortar
1.1
1.2 ASTM C404. Aggregates for Grout
2.
CcnH.~Jlt
2.!
ASTM C9! -93, Cement, Masonry. (Plastic cement conforming to the requirements of UBC Standard 25-1 may be llsed in lieu of masonry cement when it also conforms to ASTM C 9193).
2.2 ASTM C I SO, Portland Cement 2.3 ASTM C270. MOl1ar Cement
3.
Lime 3.1
ASTM C5-79, Purposes
Quicklime
for
Structural
3.2 ASTM C207-91, Hydrated Lime for Masonry Purposes. When Types Nand NA hydrated lime arc lIsed in masonry mortar, they shall comply with the provisions of UBC Standard ASTM C270-95. Section 21.1506.7, excluding the plasticity requirement.
4.
Masonry Units of Clay ot' Shale 4.1
ASTM C34. Structural Clay Load-bearing Wall Tile
4.2 ASTM C56, Structural Clay Nonload-bcaring Tile 4.3 ASTM C62-87, Building Brick (solid units) 4.4
ASTM C126, Ceramic Glazed Structural Clay Facing Tile. Facing Brick and Solid Masonry Units. Load-bearing glazed brick shall conform to the weathering and stl1lctural requirements of ASTM C73-85, Section 21.106, Facing Brick
702,1 Quality
Materials used in masonry shall conform to the requirements stated herein. If no requirements arc specified in this section for a material, quality shall be based on
fvla~~(){ily
generally accepted good practice, subject to thc approval of" the building official.
mill (j
j'
4.5 ASTM C216-86, Facing Brick (solid units)
1h
National Structural Code of the Philippines 6 Edition Volume 1
7·n
CHI\P1TH I .
Ma~;o11fy
S.2 ASTM C270, Field Tcsts Spc<:imclls for Mortar
4.6 ASTM C90-H), Hollow Brick
4.7 ASTM C67, Sampling lind Stnl(;luraJ Clay Tile 4.H
Te~tiJlg
CS30,
Struclural
Clay
9.
Non -Load
bearing Screen Tile. S.
5.0 ASTM C 129-8), Non···load bearing Concrete
Masonry Units ASTM C140, Sampling and Testing Concrete
Masonry Units 55 ASTM C426, Standard Test Method for Dryi ng
Shrinkage of Concrete Block
Grout 9. I ASTM C I 0 I 9·84, Mcthod
Rail~stccl Deformed and Plain Bars, Axle-steel Deformed and Plain Bars, and Deformed Lowalloy Bars ror Concrete Reinrorccmcnt
10.3 ASTM A496, Part 11, Cold-drawn Steel Wire
.....
6.2 ASTM C73-85, Calcium Silicate Face I3ri ck (Sand-lime I3rick)
6.3 ASTM C216, C62 or C652, Unburned Clay Milsonry Units and Standa rd Methods of Sampling and ASTM C 67, Testing Unburned Clay Masonry Units ACI· 704, Cast Stone ASTM E92b, Test Method for Compressive
St rcngt h of Masonry Prisllls
7.
Sampling and
10.2 ASTM MIS, A616, A617, A706, A767 and A 775, Deformed and Plain lliJlet-Slcei Bars,
6. J Calci L11ll silicate
6.5
or
10.1 ASTM A82, Pan I, Joint Reinforccment fo r Masonry
for COHcrete Reinforcement
Masonry Units of Other Materials
6.4
for
10. Reinforcement
ASTIV! C55-85, Concrete Building Brick
COllcretc Masonry Units
6.
Method
9.2 ASTM C476-83, Grout for Masonry
5.2 ASTM C90-85, Hollow and Solid Load-bearing
5.4
Standard Test
Testing Grout
Masonry Units of Concrete 5. I
cno,
Flexural B()Ild Strcngth or Mortar CC mC\lt
ASTM C212, Structural Cla y Facing Tile
4.9 ASTM
8.3 ASTM
Brick ;md
Connectors 7. I Wall ties and anchors made from steel wire shall conform to UBC Standard 2 I -10, Part II,
and other steel wall ti cs and anchors shall confonn to A36 in accordance with USC Standard 22-1. Wall tics and anchors made
frolll copper, brass OJ' other nonferrous meta! shall have minimulll tensile yield strength of 200 MPa.
.
7.2 All such items not fully embedded in mortar or g rOllt sh,\11 either be corrosion resistant or shall be coated after fabrication with copper, zinc or a mctal having at least equivalent corrosjon ~ resistant properties.
8, Mortal' 8. I ASTM C270-95, Mortar for Unit Masonry and
Reinforced Masonry other than Gypsum
Association of Structural Engineers of the Phllippines
CHAP Il f~ '/
SECl'I:PN 7QJ MQRTARAND GROUT . . '-. ... " , -,
, '.
,
'.
,.'
703.1 G elleral Monar and grout shall co mply with the provisions of this sec tion. Special mortars, grou ts or bondin g systems Illay be llsed, subject to satisfactory evidence their capa bilities when approved by the building official.
Ma~;orl(y
'/ 9
703.4.2 Selecting Proportions Willer con tent slwl/ be adjusted to provide proper workabil ity and to enable proper placclllclH under existing field condi tions. withou t segregation. Grout shall be spcd licd hy one of the followin g met hod s: I.
or
2.
Proportions or ingredients and any additives ,shall be hased on laboratory or field ex perience with the grou t ingredients and the masonry units to be used. The grou t sllall be specified by the pn'Jporti oll of its tCllllS of parts by volume. or
constituents in
703.2 Malerials Materials used as ingredients in mona!" and grout shall conform to the applicable requirements in Section 702. Ccmentitious materials for gro ut shall be one or both of the lime and P0!11and cement. Cemcmitious following: materials for lllo11ar shall be one or more of the following:
3.
Minimum compressive strength which wi ll produce the required prism strengt h, or
4.
Proportions by grout type shall be used as given in Table 703-2.
lime, masonry CCI1H:IlI , Portland cemellt and Illortar cement.
703.5 Additives and Admixtures
Ccmcntitiolls materials 01' additives slwll not contain epoxy resins and derivatives, phenols, .lsbcstos libel's or fire da ys. Willer lIsed in mortar or grout shall be clean amI free of dclclei-iolls amou nts of acid, alkalies 01' organic material or other harmful substances.
703.5.1 Gelleral Addi ti ves and ad mixlUres to morta r or grout used unl ess approved by lhe building offici al.
~ haJi
not be
703.5.2 Air Entrainment
703.3 MoriaI' 703.3.1 General MOllal' shall consist of a mixture of ccmclll itiollS l11
Air-entraining substances shall not be used in mortar or grout unl ess tests are conducted to determine compliance with the requirements of thi s code.
703.5.3 Colors Only pure mineral oxide, carbon black or syn th etic co lors may be used. Carbon black shall be limited to a maximulll of 3 percent of the weight of the cement.
Mortar with specified proportions of jngredients lhat differ from the mortar proportions of Table 703,1 may be approved for usc when it is demonsu'ated by laboraLOry or field experience that Ihis mortar wi th · the specified proportions of ingredients, when co mbined with the masonry units to be used in the structure, will achieve the speci fied compre~sive streng th ttl!' Water content shall be adjusted to provide proper workability under existing field conditions. When the proportion of ingredients is not specified, the proportions by mortar Iype shall be used as gi veil in Tablc 703-1.
703.4 Grout 703.4.1 Gelleral Grout shall cOllsist of a mixture of ccmcntiti ous materials and aggregate to which water has been added stich thaI the mixture will flow without segregation of the constituents. The specified compressive st rengt h of grout, 1'R' shall not be less (han 15 MP.
111
National Structural Code of the Philippin es 6 Edition Volume 1
110
CHAI'TU1! " MasolllY
704.3 Placing Masonry Units
704.1 General Masonry shall be constructed according to the provision of this section.
704.2 Materials: Handling, Storage and Preparation All materials shall comply with applicable requirements of Section 702. Storage, handling and preparation at the site shall conform also the following: 1.
Masonry materials shall be stored so that at the time of usc the materials arc clean and structurally suitable for the intended usc.
704.3.1 Mortal' The monaI', whellllsed shall bc suiTicicn!ly plastic and unit-; shall be placed with surticiellt pressure to extrude mOl"!,!!' from the joint and produce a tight join!. Deep ftlfTO\VJl1!~, which produces voids shall not be used. When mortar is used, the
illitiallle:~
joint thickness shall
;l():.
be less than 6 m!l1 or llwrc than 25 mm; subsequent L," joints shall not be less than 6 mm or more than 16 mill in
thickness.
704.3.2 Surfaces Surfaces to be ill contact with monar or grout shall be clean and free of deleterious materials, 704.3.3 Solid Masonry Units Solid masonry units sha!l have full head and bed joints.
2.
All metal reinforcement shall be free from loose rust and other coatings that would inhibit reinforcing bond.
3.
At the tillle of laying, burned clay Ulli!s and sand lime units shall have an initial rate of absorption not exceeding 1.6 liter per square meIer during a period of one minute. In the absorption test, the surface of the unit shall be held 3 mm below the surface of the water.
704.3.4 Hollow-Masonry Units Except for mortarless system all head and bed joints shall be filled solidly with mortar for a distance in from the f'ael' of the unit not less than thc thickness of the shell.
4.
Concrete masonry units shal1 not be wetted unless otherwise approved.
5,
Materials shall be stored in a manner such that deterioration or intrusion of foreign materials is prevented and that the material will be capable of
Head and bedded joints of open-ends units with bcvdc,! ends that are to be fully grouted need not be mortared. The beveled ends shall form a grout key which permits gr()\i~ within J 6 mm of the face of the unit. The units shall be tightly butted to prevent leakagc of grout.
meeting applicable requirements at the time of mixing
or placement.
6.
The method of measuring materials for mOf1ar and grout shall be such that proportions of the materials can be controlled.
7.
Mortar or grout mixed at the job site shall be mixed for a period of time not less than three minutes or Illore than 10 minutes in a mechanical mixer with the amount of water required to provide the desired workability, Hand mixing of stl1
704.4 Reinforcement Placing Reinforcement details shall conform to the requircmcnts of this chapter. Metal reinforcement shall be located ifl accordance with the plans and specification(:. Reinforcement shall be secured against displacement prior to grouting by wire positioncrs or other suitable deviccs a! intervals not exceeding 200 bar diameters. Tolerances for the placement of reinforcement in wa!!s and flexural elements shall be plus or minus 12 mm for d eqwtl to 200 mill or less, ± 25 mm for d equal to 600 mm OJ but greater than 200 mm, anc! 20 m!l1 for d greater thill: mm. Tolerance for longitudinal location of reinforcl'.li'. shaH be ± 500 mm
Exceptions: Dry mixes for mortar and grout which are blended in the factory and mixed at the job site shall be mixed in mechanical mixers until lvorkable, but not to exceed 10 minutes,
Association of Structural Engineers of the Philippines
CHAPT!: n 7 . Masonry
7· 11
All cells Clnd spaces conta in ing reinforcement shall be filled wi th grou t.
7()4.S Grotlted Masonry
clement.
704,5.2 Construt'tion Requirements Reinforcement shall be placed prior to grouting. Bolts :-;haH be accurately set with templates or by approved equ ivalent Ill C"I!l S and held in place to preve nt dislocation during gro utin g.
Prior [0 grou ting, th e gro ut space shall be clean so th at all spaces 10 be filled with grout do not conta in mOrln!"
Segregation of the grout ·materials and damage to the masonry shall be avoided durin g the grou tin g process.
704.5.1 General Conditions
Grouted masonry shall be constructed in such a manner that all clements of the masonry act together as a stru ctural
projecti ons greater than
J2
mill, mOl1ar droppings or oth er
fo reign material. Grou t shall be placed so that all spaces d es ig nated to be grouted sha ll be fi lled with grout and the grou t shall be con lined (0 those s pecific spaces.
Grout materials and water content shall be controlled to pro vide adequate fluidity for placement wit hout scgreglltion of th e corlslihlcnts, and shall be mixed thorough ly. The grouting of any section of walt shall be completed in one day with no interruptions greater than one hour. Between grout pours, a horizontal construction joint shall be form cd by stopping all wythes at the sarne elevation and
with the grout stopping a minimum of 40 mm below a mortar joint, cxcept the top of the wall. Where bond beams occur, the grout pour sha ll be stopped a minimum of 10 nlln below the 101' of th e masonry. S ize and height limi tat ions of the grout space or cell shall -no t be less Ihan shown in Table 704-1. Hi gher g ro ut pou rs Of small er cavity wid ths or cell size than shown in T.able 704 ~ I
may be used when approved, if it is demonst rated th at grou t spaces wi ll be properly filled.
Grout shall be consolidated by mechani cnl vihrnti on during placement before loss of plasticity in a manner to fill the gro ut space. Grout pours grciHer than 300 mm in height shall be reconsolidated by mechan ical vibrati on to minimi ze voids due to wa ter loss. Groul pours )00 mill or less in height shall be mechanically vibrated or puddled.
111 olle-storey buildings having wood-frame exterior walls, foundations not over 600 I11Ill high mc:tsurcd frolTl the top or the footing may be constructed of hollow-masonry units laid in running bond without mortared head joints. Ally sti.lndard shape unit may be used, provided the maso nry units permit horizontal flow of grout 10 adjacen t units. Grou t shall be solidly poured to the full height in a ile lift and sh
In multi-wythe grouted masonry, vertical barri ers of Cleanouts shaH be provided fo r all grout pours over 1.50 III in height. Where required, cleanouts shall be provided in the bottom course at every vertical bar but shall not be spaced more than 800 mm on cent er for solidly grouted masonry. When cJeanouts arc required, th ey shall be sealed after inspection and before grouting. Where. cleanouts arc not provided, special provisions .must be made 10 keep the bottom .and sides of the grout spaces, as well as the minimum total clear area as required by Table 704~ I. clea n and clear prior to grolllillg. Uni ts may be laid to the full height of the grout pour and grout shall be placed in a continu ous pour in grout lifts not exceeding 1.8 Ill . When approved, grout lifts may be greater than 1.8 III if it ca n be demonstrated the grout spaces can be properly filled.
masonry shall be built across the grout space the entire height of the grout pour and spaced not more than 9 III horizontally. The grouting of any section of wa ll between baniers shall be completed in one day with no interruption longer than one hour. 704.5.3 Aluminum Equipment Grout shall not be handled nor pumped utili zi ng aluminum eq uipment unless it can be demonstrated with the materials and equip ment to be used that there will be no dcleterio us effect on the strength of the g rou t 704,5.4 Joint Rcinforcemcllt Wire joint reinforcemen t used in the design as prin ci pal rein force ment in hoJJ ow~ulli t construction shall he co ntinu ous between supports unless splices are made by lapping:
1.
Fifty-four wire diameters in a grou ted cell, or
National Structura l Code of the Philippinos 6'10 Edition Volume 1
1-12
2.
CHAPT[I,7 Moson,y
Seventy-fivc wire diameters in the mortared bed joint, or
3.
4.
In allcrnatc bed joints of running bond masonry a distance not less than 50 diameters plus twice the spacing of the bed joints, or As required by calculation and specific location areas of minimum stress, such as points of ini1cctiOiL
J/l
Side wires shall be deformed and shall conform to ASTM A82 Joint Reinforcement for Masonry.
SECTION 705
QUiUTYASSURANCE 70S. I General Quality assurance shall be provided [0 ensure thai materials, construction and workmanship arc in compliance with the_ plans and specifications, and the applicable requiremellts of this chapter. When required, inspection records sha! I be maintail}.cd and made available to the building officiaL 705.2 Scope Quality assurance shall include, but is not limited to, assurance that: I.
Masonry units, reinforcement, cemellt, lime, aggregate and all other materials meet the requirements of the applicable standards of quality and that they arc properly stored and prepared for usc.
2.
Mortar and grout arc properly mixed using specified proportions of ingredients. The method of measuring materials for mortar and grout shall be slIch that proportions of materials arc controlled.
3.
Construction details, procedures and workmanship arc in accordance with the plans and specifications.
4.
Placement, splices and reinforcement sizes arc in accordance with the provisions of this chapter and the plans and specifications.
705.3 Compliance withI'm 705.3.1 General Compliance with the requirements for the specified compressive strength of masonry 1'", shall be in accordance with one of the sections in this subsection. The actual compressive strength of masonry I'm shall not be less that 4 MPa or the minimum requirement of NSCP Volume on HOllsing, whichever is lower.
705.3.2 Masonry Prism Testing The compressive strength of masonry determined in accordance with ASTM E447 for eilch set of prisms shall equal or exceed I'm. Compressive strength of prisms shall be based on tests at 28 days. Compressive strength al seven days or tllrec days may be used provided a relationship between seven-day and three-day and 28-day strength has been established for the project prior to the Wlli of construction. Verification by masonry prism testing shall meet the following: l.
A set of five masonry prisms shall be built and tested in accordance with ASTM E447 prior to the starl of constIUction. Materials used for the construction of the prisms shall be taken from those specified to be used ill
Association of Structural Engineers of the Philippines
CHAP TE n 1 . flAasolll y
the project. Prisms ~ h(lll be constructed und cr the obse rva ti on of the cngi neer-of-record or special inspct:lor or all lIpprovcd agenc y ,lIld tested by an approved agCJH.:y. 2,
When full allowahle stresses are lIsed in design, a ~C ( of
pri$llls shall
three
be
buill
and
tested
705.3.4 Unit Strength Method Verifi cation by the un it strength method sha ll mee t tht'
foll owing: I.
during
construction in accordance with ASTM E447 for each 2
460 m of wall areH, but not less than One sc t of three masonry prisms for th e project.
J.
2.
Exception:
in design, testing during construct ion is not requiJed. A leiter of certification from the manufacturer and/or suppl ier of the material s used to verify the /,,,, in accordance with Section 705.3.2, Item J, sha ll be provided at the time of, or prior to, delivery of the materials to the j ob si te to ensure the materials used in co nstruction arc represen tative of the materials used to construct the prisms prior to constnlction. ;~
Prior to the start of constrllctioll, prism testing may be used ill lieu of testiflg the lin;' strength. During cOflsfmclioll, prism testing may also be used ill lieu of testing Ihe utlil
A masonry prism tcst record approved by th e building official of at least 30 masonry prisms which were built and tested in accordance with ASTM E447. Prisms shall have been constructed under the observation of an engineer or special inspector or an approved agcncy and shall ha ve been tested by an approved agency. Masonry pri sms shall be corresponding cons truc ti on.
represen tative
strength and the grout as required by Section 705.3.4, Item 4. 2.
When one half the ;:lllQwable masonry stresses are llsed in design, testing is no! requ ircd for the units. A lett cr of cert ification from the Ill,Ul ufacwfcr of the un its shall hc provided at the time of, or prior to, de li very of the units t9 Ihe job site (0 ass ure the units compl y wit h thc com pressive stren gth required in Table 705-1; and
3.
Mortar shall comply with the mortar type .required in Table 705-1; and.
4.
When full streSSeS arc lIsed in design for concrete grout shall be tested for eHeh 460 III of wall area, but not less than onc tcst per project, to show co mpli ance wi th the co mpress ive strength required in Table 705-1 , Footnote 4. 1ll
of the
3.
The average compressi ve strength of th e test record sha ll equal or exceed 1.33 I'm.
4.
When full allowable stresses are used in design , a set or Ihree masonry prisms shall be built durin g constructi on in accordance with ASTM E 447 for each 460 1112 of wall area, but not less than one set of three prisms for the project.
5.
Whcn fuJI allowab le stresses arc used in design, units shall be tested prior 10 construction and lest units during co nstruction for each 460 1112 of wal! area for compressive strength to show compliance with th e co mpressive strength rcq uirc(1in Table 705-1; and
When one lwlf the all owable masonry stresses arc used
70S.3.3 Masonry I'rislll Test Record Compressive strength verification by masonry pri sm test records shall meet !he follow ing:
I.
'I 1:1
When one half the allowable masonry stresses are used in design, field testing during construction is not required. A Jetter of cel1ification from th e supplier of th e materi als to th e job sitc shall be provided at the liJ~e of, or prior to, deli very of the materials 10 assure the' materi als lIsed in const ru cti on arc representati ve of lhe materials used to develop the prism te st reco rd in accoillancc wilh SCl:tion 705. 3.3, Item I.
5.
When one half the all owable stresses arc used in design fol' concrete masonry, lCs ti ng is not required for the groll t. A Jetter of certification from the supplier of the grOlJt shall be pro vided at the time of, or prior 10, deli very of the grout to the job site to assure the grollt complies wi th the compressive strength requ ired in Tabl e 705- 1, Foolnote 4; or
6.
When full allowable stresses are used in design for clay maso nry, grout proportions shall be verified by the cngineer~of~record or special inspector or an approved agency to conform wilh Table 703-2.
7.
When one half the allowable masonry stresses are used ill de$ign fo r cla y masonry, a letter of cCI1iri cation fro m (he suppl icr of Ihe grout shall he provided ilt the timc of. or prior to, dcli ve.ry of the groul to the job site to assure the grout conforms to the proporti ons of Table 703-2.
National Structural Code of the Philippines G'I> lodition Volum e 1
7·1-1
..
~
CHA F)"fEH ., . Masonry
70S.3.5 Tes ting Prisms from Constl'ucted Masonry When approved hy the building official, ,Hxcptill1Ce of masonry which docs not mcet the requirements of Section 705.3.2. 705.3. 3 or 705. 3.4 sha ll be permitted to be based Jlla ~o nry construction il)
on tests of prisms CUI fro m the accordancc with th e followin g: I.
2.
A sel of three masonry prisms that arc at Icasl 28 days old slwll bc saw cut from the masonry for each 460 ml: of th e wall area thm is ill question but not less than one sel of three maso nry pri sms for th e project. The length, width and hei ght dimensions of Ihe pri sms shall comply with the requirements of ASTM E 447. Transporting, preparation and testin g of pris ms shall be ill accordance with ASTM E 447. The compressive stren gth of prisms shall be the value calcul atcd in accordance with UB C Standard 2 J -1 7,
Secti on 2 J . 1707.2. except that the net cross-sectional area of the prism shall be based On the net mort ar bedded area.
70(,.1 Gcncral
706.1.1 Scope The design or :llasonry structures shall co mpl y wit h th e ~l lJ owabJc ~trcs~' Jcs ign pro vis ions or Section 707, or the strcngth dc·sign provisions of Section 708 or th e empiric;! design provi sions of Section 71 0. and with the pro visions of this section. Unless otherwise slaled, all c
Plans submitted for approval shall desc ribe lhe required de sign strengths of masonry material... and ins pection requirements;' for whi ch all parts of (he structure were designed, and any load lest requ irements. 706.1.3 Design Loads
3.
Compliance with the requ i" rement for the specificd co mpressive st rength of masonry, f',~, shaH be considered satisfied provided the modified compressivc stren gth equals or exceeds th e specified /',,,. Additional testing of speci mens cut from locat ions in question shall be permitted.
705.4 Mortar Testing
Wh en required, mort ar shall be tested ill accordance with ASTM C 270.
Sec Chapter 2 for dcsigll loads and load comhil li.llio ns. 706.1.4 Stack Bond Jil bearing and 1I0nbearing Willi s, except veneer wa ll s, i f less than 75 percent of the units in any transverse veJ1 icai pl ane lap the ends of the unit s below a distance less than one hal f Ihe height of th e unit, or less than one fourth the length of th e unit, the wa ll shall be consi dered laid in stack bond. 706.1.5 Multi-wythe Walls
705.5 Grout testing
Wh en required, grout shal! be tes ted in accordance with ASTM C 476-83. /105.6 Recycled Aggregates
Recycled aggregates shall refer to those materi als whose mi xt ures are part of masonry blocks or concrete debris th at have been crushed for fe-use. Recycl ed aggregates shall pass the necessary (eSls before considered for re-use.
706.1.5.1 General
All wythes of multi ·wythe walls shall be bonded by grout or tied togeth er by cOITOsioll-fesistant wall ties or joint reinforcement co nforming to the requirements of Section 702, and as set forth in thi s secti on. , 706.1.5.2 Wall Tics in Cavity Wall Construction
Wall ti es shall be of sufficient length
10
engage all wythc.s.
Th e pOl1ion of the wal! ties within the wythe shall ! ,,:
completely embedded in mortar or grout. Thc ends oj" t· wall lies shall be bellI 10 90-degrce an gles wit h an eXlc!l:.i:. i.t nol less than 50 mill long. Wall tics not comptc.I<+,· cmbedded in mortar or grout between wYlhes shaH be it single piece wil h each end engaged in each wythe. There shall be ,it least one rnl 0 111m wall ti c for each OAO of wa ll area. For cavity wall s in whi ch Ihe width of ir cavit y is greater than 75 Illlll , but not more than 11 5 m lll . .least onc 10 mill diameter wall ti c for each 0.25 1112 oj ,. ;, ;; area shall be provided .
Association of Structural Engineers of the Philippines
Ti cs in alternate courses shall be staggered. The maximum vertical dist ance between ties shall not exceed 600 mm and Ihe max im u lll horizo nlu l distance be tween ti c~ sh all HOI exceed 900 mill. Add it io nal tics spaced not more (ha n 900 mill apart shall be provided around openings wi th in 11 di stance of 300 mm fro m the edge of the opening. Adj ust able wall ti cs shall meet the foll owing req uiwmcn ts:
I. Onc ti e shall be provi ded for each O. J 6111 2 of wa ll area. Ho ri zon ta l and ven ical slHlcing sha ll not exceed 400 I11 1ll. Max imum misali gnment of bed joi nts fro m o lle wyt he to th e other shall be 30 ml11 . 2.
Maximum clearance between the conn ecting parts o/" the lie shall be 1.5 mm. When used, pintle ties shall have at least two 5 n Ull di amctcr pintle legs.
Wa ll ti cs of di fferent size and spac ing that provide eq uiv:'ll elll stre ng th between wythes may be used.
706.1.5.3 Wall Tics for Grouted Multi-wythe Construction Wythes·{)f multi -wyth e wall s shall be bonded together with at leas t 4.8 mm di ameter steel wall tie for each 0.20 m2 of area. Wall li es of different size an d spacing th at provide eq ui va lent strength between wythes ma y be used. 706.1.5.4 Joint Reinforcement
Prefabricated j o ill t reinforcemeIll for masonry wall sh all have at least one cross wire o f at least No.9 gage steel for each 0.20 m2 of wall area. The vertical s pi.~cing uf the joilll rei nforce ment sh all not exceed 400 mill . T he longi tudinal wires shall be thoroughly embedded in the bed joint mortar. The joi nt rei nforce me nt shall e ng:'lge al l wytlles. W here (h e space betwee n tied wythes is solidly fill ed wit h grou t or mortar, lhe all owable stresses and ot her provisions for masonry bonded walls shall apply. Wh ere the space is !lot filled, tied walls sha ll conform to the allowable stress, lateral support, thickness (ex cluding cavity), height and tie requi rements for cavi ty walls.
706. 1.6 Ve r ti cal Support
706.1.7 Lateral Support Lat eral su pport of mason ry may he prov ided by cmss Willis, (o lumns, pilas ters, countc rfor!s or buttresses where spallning horizollla lly or by noon. , heams, gi rt s or roofs wlle re spann ing vert ically.
Th e clear distance betwee n la teral suppon~ of" a be.ull shall not exceed 32 limcs the leas! wid th of the compression area.
706.1.8 Protcction of 'I'ics ~Uld Joint Rcinforcement A mini mulll of 16 I1Ull mortar cover shall be provided between tics or joint rein fo rce me nt a nd any exposed face. The thickness of grout or mortar between masonry units and join t reinforcement sha ll nOI be less than 6mm, except th at 6 mill or smaller diameter reinforcement or bo lts may be placed in bed joints wh ic h are at least twice the thickness of the reinforce ment or bolts. 706.1.·9 I)ipes and Co ndui1s Embedded ill Masonry Pipes o r conduit shall not be e mbedded in any masonry in a manner that will red uce the capacity of thc masonry to less l ilan that necessary for rcqlli red stren gth or req uired ti re
protection. Placement of pi pes or condui t ~ in unfilled corcs of ho llow· uni t nwsonry 5h,1I1 nOI be considered as embedment. Exceptions: I.
Rigid electric conduits may be embedded in structural lI!(Jsonry when their locations have been de tailed on rh e approved plan
2.
Any pipe or conduit may pass ve rtically or horizontally through any masonry by means of a sleeve at least large enough to pass allY hub or coupling on (he pipelille. Such sleeves shall not be placed closer Ihall three diameters, cenrer to center, flor shalf they unduly impair the strength of constructiolT.
706.1.10 Load Test When a load test is required, the member or portion of the structure under consideration shall be subjected 10 a superim posed load equal to twice the design li ve load plus one hal f of 'he dead load: O.5D + 0.2L
S tructu ra l members providing vert ica l support of masOIi ry
shall provide a bearing surface on whic h the initial bed joi nt shall not be less th an 6 ml11 or more th an 25 111m in thickness and shall be of noncombustible material, except where masonry is a Ilolls tructural decorat ive fea ture or wearing surface.
Th is load shall be len in position fo r a period of 24 hours before remova l. If, du ring the tes t or upon removal of lhc load, th e member or portion of th e structure shows evidence of fai lure, such changes or modifications as are necessary to make the sl"ruc ture adequate for the rated capacity shall be made; or where approved, a lower rating shall be established.
National Structural Code of tile I'llilippines 6'" Edition Volu me 1
"1 · 16
C/li\PIEli 7· Masonry
reinforcemenl or by hori zontal rei nforcement spaced not over 1.2 III and fully embedded in grout or mortar.
A fl cxul'
Icst if Ihe maximulIl deflection D ,H the end of the
24~ hour
period does not exceed the value of Formu la (706-1) or (706-2)
I
f) ~ - - -
(706- 1)
200 ."
:. ' .
12
D=-4,000,
(706-2)
706,1.11 Reuse or Masonry Units Masonry units may be reused when clean , whole and confonning 10 the olher requ irements of thi s sectioll . All structural propcI1ics of masonry of reclaimed units shall be determined by approved test.
706.1.12 Special Provision'5 in Area of Seismic Risk 706.1.12.1 General
Masonry struct ures constructed in the seismic zones shown in Figure 208- J shall be designed in accordallce with the design requirements of this chapter and the special provisions for each seismic zone given in this sec ti on. 706.1.12.2 Special Provisions rol' Seismic ZQlle 2
Masonry stru ctures in Seismic Zone 2 shall co mpl y wilh the following special provisions: J.
Columns shall be reinforced as specified in Sections 706.3.6,706.3.7 and 707.2.13.
2.
Vertical wall reinforcement of ,II Jellst J 30 mm2 in cross-sectional area shall be provided continuously froIn sUppOIl to su pport at each corner, at each side of each opening, at the ends of walls and at maximum spacing of 1.20 m apart horizontally throu ghOllt walls.
3.
4.
Horizontal wall reinforcement not less than J30 mm 2 in cross-sectional area shall be provided (1) at the bottom and lOp of wall openings and shall extend not less th an 600 mm Or less than 40 bar diameters past the opening, (2) continuously at structurally connected roof and fl oor levels and at the top of walls, (3) at the bottom of wa lls or ill the top of foundations when dowel ed in wa lls. and (4) at maximum spaci ng of 3.0 III unless 1Illiful"lnly di ~lributcd joilH rein fo rcement is pro vided. Reinforce mcn{ at the top and bOil om of openin gs when conlinuous in wa lls may be used in determini ng the maximulll spacing speci fied ill Itelll I of th is paragraph. Where stack bond is used, the minimulll horizontal reinforcement ratio shall be O.0007bc This ratio shall be satis fied by uniformly distributed joint
S.
The follo wing m;'llcriais shall 1101 bc lIsed ;'IS parI of the vertical or latcml IO;'ld ~ rcsi s ting system: Typc 0 mortar, masonry ccrnent. plasti c ccment, nOll-load bearing masonry units and glass block.
706.1.12.3 Special Provisions for Seismic Zone 4 All masonry structures buill in Seism ic Zo ne 4 shall be designed and construcltd in accordance with requirements for Seismic Zone 2 and with the following additional requirements and limitations:
I. Column Reinforcement Tics
In columns Ihat are stressed by tensile Or compressive axial overturning forces from sei sm ic loading. the spacing of colullllI lies shall not exceed 200 mill for the full height of such columns.
In all other columns, ti cs shall be spaced a maximum of 0.20 m in the tops and bottoms of the columns for a distance of the greatest among ( I) one sixth of the clear column height, (2) 450 111m, or (3) the maximum column cross-sectional dimension.
Tic spacing for the remaining col umn height shall not exceed the lesser of 16 bar diameters, 48 tie diamcters, lhe least column cross-sectional dilllension, or 450 mill. Column lies sha ll terminate with a minimum 135-degrec hook with extensions not less than six bar diameters or J 00 mill. Sueh extensions shall cngtlgc the longitudinal colum.n reinfo rcement and project into the interior of the column. Books shall comply wilh Seclio n 707.2.2.5, It em 3. Exceptions: Where ties are placed ill horizontal bed joints, hooks shall consist of a 90-degree bend having an inside radius of not less than four tie diameters plus an extension of 32 tie diameters. 2. Shear Walls 2.1 Reinforcement The portion of the reinforcemcnt rcq uired to resist shcar sha ll be uniforml y di stribut ed and shall be joill! IcinfOi cclIlcnl , dcCormed bars or a combin ation thereo f. The spacing of reinforcem ent in each direction shall !lot exceed one half the length of the elemenl. nor one half tho:height of the elemenl , nor 1.2 nl .
Joint reinforcement used in exterior walls and cOllsid(:j"i'· ~ . the determination of the shear strength of the J1lcmh ~" be hot-dipped galvanized in accordance with i\STM " & A 641.
Associatio n of Structural Engineers of Uw Philippines
CHAPTE:n 1 .
lv1a~>onf'y
"/·17
Rcinforcement required to resist in-plane shear shall be terminated with;! stalHlard hook
a~
defined in Section
707.2.2.5 or with an cx t e n ~ jon of proper embcdmcnt length beyond the reinforcement at the end or the wall scction. The hook or extension may be turncd up, down or hori7.ontaliy. Provisions shall be made not to obstruct grout placcment. Wall reinforccment terminatin g ill columns or bcams shall be fully anchored into these elements.
2 .• Bond Multi-wythe grouted masonry shear walls shall be designed with consideration of the adhesion bond strength between the grout ,lfld masonry units. When bond strengths are not known frolll previous Icsts, thc bond stren gt h shall be determined by tesls.
4. Concrl'-te Abutting Structural Masonry Concre te abutti ng strm;tural masonry, suc h as at s(ancr courses or ill wall in tersections not designed as true
separation joints, shall be rnughcncd to II full amplitude of 1.5 Jlllll and shall be bonded to the masonry in accordance with the requirements of thi s chapter as if it were masonry. Unless keys or proper reinforcemcnt is ptoyided, vertical joints as specified in Section 706.1.4 shall be considered to be stack bond and the reinforcement as required j'nl' st,\ct.; bono shall extend through the jOint and be anchored into the concrete.
706.2 Allowable Stress Design and Strength Design Requirements for Unrcinforccd and Reinforced Masonry
2.3 Wall Reinforcement All walls shall be rcinforced with both vCl1icai and horizontal reinforcclllcm. The sum of thc areas of horizontal and vert iC'll reinforcement shall be HI least 0.002 times the gross cross~scctional area of the Willi, and the ' minimum area of reinforcement in either direction shall 110t be less than 0.0007 times the gross cross-sectional area of thc wall. The mjnimum steel requirements for Seismic Zone 2 in Section 706. 1.l2.2, Items 2 and 3, may be included in the sum. The spacing of reinforcement shall nol exceed 1.2 In. The diameter of reinforcement shall not be Jess than JO mm except that joim reinforcement may be considered as a part or all of the requirement for minimum reinforcement. Reinforcement shall be continuous around wall corners and through intersections. Gnly reinforcement which is continuolls in the wall or clement shall be co nsidered in computing the minimum area of reinforcement. Reinforcement with splices conforrning to Section 707.2.2.6 shall be considered as continuous rei nforecmen!.
2.4 Stack Bond Where stack bond is used, the minimuIll horizontal reinforcement ratio shall be O.OOISbl. Where open-end units arc used and grouted solid, the minimum horizontal reinforcement ratio shall be O.OO07bt. Reinforced h o llow~lI nit stacked bond co nstru ct ion which is part of the se i smic~ re sis till g .system shall USe opc ll ~c nd units so that all head joints arc made solid, shall usc bond beam units to faciJit,ltc the nnw of grout and shall be grouted solid.
706.2.1 General In addition to the rcq uireJllclll!> of Section 706. 1, the design of Illnsonry struct urcs by the allowable stress desi gn method and strength design method shall comply with the requirements of this section. Additionally, the design or reinforced masonry structures by these desi gn methods shall comply with the requircments of SectiDIl 706.3. 706.2.2 Specified Compressive Strength of Masonry The Itll owablc stresses for the design of masonry shall be based 011 value of selected for the construction.
rill
Verification of the value of I'm shall be based on compliance with Scction 705.3. Unless otherwise spccified, f'm shnl! be based on 28 -day te-sts. If other than a 28 ~ day test age is used, the value of j'HI shall bc as indicated ill dc'sign drawings or specifications. Design drawings shall show the value of m for which c
r
706.2.3 Effeelive Thickness 706.2.3.1 Single-Wythe Walls The effective thickness of single-wythe walls of either solid or hollow units is the specified thickness of the wall. 706.2.3.2 Multi-wythe Walls The effcctive thickness of IlHilti -wythc walls is th e specific, ) thickness of the wall if the space between wythes is filkd with mortar or grout. For walls with an open space between wythes, the effective thi cknC'-ss shall be determined as for
cavity walls.
3. Type N Mortar Type N mortar shall not be used as palt of the laleral~load-resis(ing system.
ve l1ical~or
t1
National Structural Code of the Philippines 6 ' Edition Volume 1
'(· Iil
CHAP-rEF! "I
Masonry
01" the wal! parallel 10 the shear forces may be assumed 'to carry horil.ollta] shear.
706.2.3.3 Cavily Walls
Where bOlh wylhcs of
cavity wall is composed of a single wythe and a and both sides arc axially loaded, each side of th e cavilY waH shilll be considered 10 aCI independently and the effective thickness of each side is as defined in Sect ions 706.2.3. 1 and 706.2.3,2. Where only one side is axi ally loaded, the effective Ihickness of the cavity wall is the square root of" the su m of the sq uares of tile speci fied thicknesses of the sides. 11
multi~wythc,
706.2.3.4 Columns
The effect ivc thi ckness for rectangular columns in the di rcction considered is the specified thickness. The effective thickness for nOIl~rcctanglllar columns is the thi ckncss of the square column with the same moment of incrtia about its axis as that about the axis considered in the actual column. 706.2.4 Effective Height
706.2.7 DistribuHon of Concentrated Vertical Loads in Walls The length of wall laid up in running bond which may be considered cap"ble of working al the maximum allowable ('I)mpressive stress to resist vertical concentrated loads shall L~; . exceed the cel1ter~IO~cclltcr distance between Stich loads. nor the width of bearing area plus rour limes (he wall thickness. Concelltrated vertical loads shall not be assumed 10 be distributed across continuous vertical monar or con tro! joints unless clements designed to di stribute the conce ntrated vcnica] loads arc employed. 706.2.8 Loads OIl NOlluearing Walls Masonry walls lIsed as interior partitions or as exterior surfaces or a building which do not carry vcrtical loads imposed by other clements of the building shall bc designed to carry their own weight plus any superimposed fini sh and IHteml rorces. Bonding or anchorage of nonbcaring walls shall be adequate 10 support (he walls and to transfer lateral forces to the Suppo!1ing elements. 706.2.9 Vertical Denectioll
Elements supporting masonry shall be designed so that their vertical deflection will not exceed 11600 of the clear span under total loads. Lintels shall bear on supporting masonry on each end such that al!owable stresses in the supporting masonry arc not exceeded. A minimum bearing length or 100 mill shall be provided for lintels bearing on masonry.
The effective height of columns and walls shall be taken as the clear height of members laterally supported at [he top and bottom in (\ direction normal to the mcmber axis considered. For members nOI supported at the top normal to the axis considered, the crfective height is twice the height of the member above the support. E:Jfective height less than clear height may be llsed if justified.
706.2.10 Structural Continuity Intersecting structural clements intended to act as shall be anchored together to resist the design forces.
706.2.5 Effective Area
706.2.11 Walls Inlersecling
The effective cross~sectional area shall be based 011 the minill1l1!l1 beddcd area of hollow units, or the gross area or solid units plus any grouted area. Where hollow unils arc used with cells perpendicular to the direction of stress, the effective (uea shall be the lesser of th e minimum bedded area or the minimulll cross~sec ti o llal area. Where bed joints are raked, the effective area shall be correspondingly redu ced. Effective areas for cavity walls shall be that of the load ed wythes, 7()6.2.6 · Effectiv(~ ,\lidth of Intersecting \V;,lIs
Where a shear wall is anchored to an intersecting wall or walls, the width of the overhanging flange form ed by the intersected wall on ei ther side of the shear wall, which may be assumed working with the shear wall for purposes of" flexural stiffness calculations, shall nOI exceed six times the thickness of the intersected wall. Limits of the effective flan ge may be waived if justified. Only the effective area
unit
wHh Floors and Roofs Walls shall be anchored to all !loors, roofs or other eleme nts which provide lateral SUpp0I1 for the wall. Where noors or roors are designed to transmit horizontal forces to walls. the anchorage to such walls shall be designed to resis t the horizontal forcc. 706.2.12 Modulus of Elaslicity of Materials 706.2.12.1 Modulus of Elasticit)' of Maso",'),
The moduli for masonry Illay be estimated as provided below. Actual values, where required, shall be established by lest. The modulus or elasticity of masonry shall be determined by the, secant method in which the slope of the. line for the modulus of elaslicity is taken from O.05f'", to a point on the curve at 0.33 I'm. These values arc not to be reduced by one half as scI fonil in Seclion 707. J .2.
Association of Structural Engineers of the Philippines
CIIAI'TEH I Maso",y
Modulus of clas ti<: ity of clay or s hal ~ unit masonry. J ~.",
= 750/,,,,,
205 OPt! maximum
(706 -3 )
l 19
di st ribut ed 10 the wyllles accordi ng hJ Ihei r rcspt.:cti vc Ikxu ral ri gidit ies 706.3 Alternative Strength Design (ASD) and S trength Des ign Requirements for Reinfor('ed Ma sonry
Modulus of l!lasticity of concrele unit masonry.
1:·," = 750/,,,,, 20.5 (JPa maximum
(706-4) 706.3.1 General
706.2.12.2 Modulus of Elasticit), of Steel (70G·S) .. ,
E,=200 GPa
706.2.13 Shear Modulus of Masonr),
G = 0.4 Ii:.,
(706·6)
706.2.14 ('Iacemcnt of Embedded Anchorllolts 706. 2.14.1 General
706,3.2 Plain Bars The use of pi
requireme nts for plate anchor boll s, hcadcd anc hor boilS find bent biir anchor bolts sha ll be detcrmincd in accordance with this subsection. Bcnt bar anchor bolts shall have a hoo k with a 90-dcgree bend with all inside diam ete r of three bolt diameters. plus all cxtension of" one and one Iwlf bo lt diameters at thc frce cnd . Plat e anchor bolts shall have a plate welded to thc shank to provide anchorage eqlliv Hlent to headed anchor bolts. PIaCCIl"lCIll
The effec tive embedmen t depth Ib for plate or headed anchor bolts shall be the length of embedment measured pe'l)end icul ar from the surface of the masonry to the hc.uin g surface of th e pl ate or head of the ancho rage , and II)
for bcnt bar anchors shall be the length of embedment measured perpend icular from the surface of the mason ry 10 the bearin g surface of the bent end minus one anc hor bolt d iameter. All bolls shall be grouted in place with ill leasl 25 Jl1m of grou t between the boll and the rnasonry. except th at 6 fllll1 bolts Illay be placed in bed joints which area al least J 2 mm in thickness. 706.2.14.2 Minimum Edge Distance
TIle minimum anchor bolt edge distallce !l>c measured from the edge of the maso nry par·alle! with the anch or bolt to the surface of the anchor bolt shall be 38 rnm. 706.2 .. 14.3 Minimum Embedment Depth The minimu m embedment depth of anchor bolts fOlll"
In addition 10 the requirem en ts of' Sect ions 706.1 and 706.2, tbe design of reinforced masonry i; lructu res by th e working stress design method or the stren gth des ign method shall co mply with the require ments of thi s sec tion.
boll d iamclers but not less th an 50
Ih shall be
The dear di stance between parallel h'l!"s, except in columns, shall nol be less than Ihe nominal diameter of the bars or 25 llllll. except thaI bars in a splice may be in contact. Thi s clea r distance requirement applies 10 tile dc,lr di stance be twee n a contact splice and adjacen t splices or bars.
The clear distance between th e su rface of a bar and any surface of a masonry unit shall not be less th an 6 mm for fine grou t and 12 mm for coarse grout. Cross webs of hollow units may be used as support for horizontal rei nforceillent.
706.3.4 Anchorage of Flexural Reinforcement The tension or co mpression in
The shear is not over one half" that permittcd, induding ,lIlow"Ulcc for shear rcin forcc mclH where pro vided.
2.
Add it ional shear rei nforcement in excess of th at required is provided each way from the cutoff a dist;mcc eq ua l to the dcpth of the bea m. The shear reinforccment spacing shall nol exceed d/8 rJ,.
3.
The cont inu ing bars provide double lhe arca requ ired for flexure at that point or double the perimctcr required for reinforcin g bond.
111111.
706.2.14.4 MinimulIl Sp:ldllg bc(wcen Bolls The minimum center-to-ccnter distance between anchor bolts shall be four bolt di ameters. 706.2.15 Flexural Resistance of Cavity Walls For computing the fl exural resi stance of cavity walls. lateral loads perpendi cul ar (0 the plane of the wall shall be
1h
National Structural Code of the Pllilippines 6 Edition Volum e 1
7·20
CHAPTEFl 7· Masonry
AI least one third of the total rcin/{)fccmcnt provided for negative mOllle/ll at the support shal! be extended beyond the extremc position of the poill! of in(Jcdio1l a distance sufficicllt to develop one half the allowable stress in the bar, not less than 1116 of the clear span, or the depth d of the mcmber, whichever is greater. Tensile reinforcement for negativc moment in any span of a e);j!inuous restraincd or cantilever beam, or in any member of a rigid frame, shal! be adequately anchored by reinforcement bond, hooks or mechanical anchors in or through the supporting member. At least one third of the required positive moment reinforcement in simple beams or at the freely suppOJ1cd end of continuous beams shall extend along the same face of the beam into the SUppOi1 at least J 50 mm. At least one fourth of the required positive moment reinforcement at the cOlltinuous end of continuous beams shall extend along the same face of the beam into thc support at least ISO mill. Compression reinforcement in flexural members shaH be anchored by ties or stirrups not Jess than () mm in diameter, spaced not farther apa!1 than 16 bar diameters or 48 lie diameters, whichever is less. Such ties or stinups shall be used throughout the distance where compression reinforcement is required.
706.3.5 Anchorage of Shear Rcinfoffcment. Single, separate bars used as shear reinforcement shall be anchored at each end by one of the following methods: I.
2.
3.
Hooking tightly around the longitudinal reinforcement through 180 degrees. Embedment above or below the mid-depth of the beam on the compression side a distance sufficient to develop the stress in the bar for plain or deformed bars.
By a standard hook, as defined in Section 707.2.2.5,
project beyond the end of the bend at least 12 stirrup diameters.
706.3.6 Lateral Tics AI! longitudinal bars for columns shall be e.nclosed by lateral tics. Lateral suppO!1 shall be provided to the longitudinal bars by the corner of a complete tic having an included angle oj' not more than 135 dcgree~' or by a standard hook at the end of a tic. Tile corner bars :;liall have such SUPPO!1 provided by a complete tie enclosing the. longitudinal bars. Alternate longitudinal bars shall have such lateral support provided by tics and no bar shall be farther than 150 mm from such laterally supported bar. Lateral tics and longitudinal bars shall be placed not le.';s than 38 mm and not more than 125 mm from the surface or the column. Lateral tics may be placed against the longitudinal bars or placed in the ,horizontal bed joints where the requirements of Section 706.1.8 are met. Spacing of tics shall not exceed 16 longitudinal bar diameters, 48 tic diameters or the least dimension of the column but not more than 450 111m. Tics shall be at least 6 mm in diameter for 20 mm or smaller longitudinal bars and at least J 0 mm for longitudinal bars larger than 20 mm. Ties smaller than J 0 mm may be used for longitudinal bars larger than 20 mm, provided the total cross-sectional area of such smaller ties crossing a longitudinal plane is equal to that of the larger tics at their required spacing.
706.3.7 Column Anchor Bolt Ties Additional tics shall be provided around anchor bolts which are set ill the top of columns. Such ties shall engage at least four bolts or, alternately, at least four vertical column bars or a combination of bolts and bars totaling at least four. Such tics shall be located within the top 125 mill of the 2 . column and shall provide a total of 260 nun or more l!l cross-sectional area. The uppermost tie shall be within 50 111m of the top of the column.
considered as developing 50 MPa, plus embedment sufficient to develop the remainder of the stress to which the bar is subjected. The effective embedded length shall not be assumed to exceed the distance between the mid-depth of the beam and the tangent of the hook.
706.3.8 Effective Width B of Compression Area In computing flexural stresscs in walls where reinforcement occurs, the effective width assumed for running bond
The ends of bars forming a single LJ Of multiple LJ stirrup shall be anchored by one of the methods set forth in Items 1 through 3 above or sha!l be bent through all angle of at least 90 degrees tightly around a longitudinal reinforcing bar not less in diameter than the stirrup bar, and shall project beyond the bend at least J 2 stirrup diameters.
masonry shall not exceed six times the nominal wall thickness or the center-la-center distance between reinforcement. Where stack bond is used, the effective width shall not exceed three times the nomina! wall thickness or the center-to-center distance between reinforcemcnt or the length of one unit, unless solid grouted open-end units arc used.
The loops or closed ends of simple U or multiple U stirn!ps shall be anchored by bending around the longitudinal reinforcement througb an angle of at least 90 degrees and
Association of Structural Engineers of the Pililippines
CHAPTEn 'l . Masonry
7·21
707. 1.4 Des ign Assutnl)(ions
The working stress design proced ure is bllsed Oil working stresses and linear stress-st rain distribu tion assumpt ions with al l strcsses in the cl astic range as fo ll ows:
707.1 Ge neral 707.I.I Sco pe The design hI' inaso nry structures usin g all owa ble stress design sh;ill compl y with the provision s of Sec ti on 706 unc.l this sec tion.
I.
Pla ne sections be fore bendin g remain pla ne aft cr bc nding.
2.
Stress is proportional to strain.
J.
Masonry clcmcnts combin e to form a IH) ll1o ge noLl,1 mem ber.
Stresses in cl ay or concret e maso nry under
service loads shall not exceed th e va lues given in this
707.1.5 Emuedded Anchor BoiL,
sec tio n .
707. 1.5.1 General 707. 1.2 Allowaule Masonry Stresses When qualit y a$;su mncc provisions
do
not
incl ude
require ment s for spec ial inspecti o n as prescribed in Section 70 1, the all owilble stresses for masonry in Sec ti on 707 sha ll be reduced by one h'llf.
\A/ hen one half all owa bl e ma sonry stresses arc used ill Seismic Zone 4, the va llie of I'm from Ta ble 705~ J sh all be
limi ted to a max imum of J () MPa for concrete maso nry and 18 MPa for clay maso nry unless the value of/'/II is verified by tes ts in a!.:co rdancc with Section 705.3.4, It elll!) 1 and 4
Allowa ble loads for pl ate
707.1.5.2 Tension All owable loads in tension shal! be the lesse r val ue se lected from Table 707-1 and 707-2 or shall be determi ned from the lesser of Forilluia (707-1) or Forillu ia (707-2). (707 - 1)
or 6. A lettcr of certifi cation i!) not required.
(707-2)
Whcn one half all owab le maso nry st resses are used for design in Seismic Zo nes 4, the value of/,,,, sha ll be limited (0 10 M Pa for concrete maso nry a nd 18 M Pa fo r clay maso nry fo r Secti on 705.3.2, item 3, a nd Sect io n 705.3.3, Item 5, un less thc val ue of /,,,, is verifi ed ·during construction by the 1csling requireme nt s of Secti o)) 705.3.2, It em 2. A letter of certificatio n is not required.
The area A" sh all b~ the lesser of Fonmil a (707·3) or Fo rm ula (707-4) and where th e projected areas o r adjacent
707. 1.3 Minimum Dimensions for Masonry Structures L oca ted in Se is mi c Zones 2 and 4 Elements of masonry stl1lc tures located in Se is mi c Z.olles 2 a nd 4 shall be in accordance with this section.
707.1.5.3 Shear
707.1.3.1 Bearing Walls Thc nom inal thickness of reinforced masonry bearin g walls shaH not be less than 150 Illlll except th at no mi na! 100 !TIm load-bearing re info rced hollow-clay unit masonry walls may be used, provided net area uni t strength exceeds 55 MPa, un its are laid in nlllning bond , bar s izes do nol exceed 12 mill w ilh no more tha n Iwo bars or o ne s pl ice in
707.1.3.2 Columns The least nominal di mension of a reinforced masonry column shall be 300 mm except th at, for AS D, if the a ll owab le stresses are reduced by one hal f. the minimum nomin al dimension shall be 200 mm.
anchor boilS c verlap, At' or each anchor bo lt shall be reduced by o ne half o f Ihe overl a pping area. A"
A"
(707-3) (707-4)
Allowable loa ds in shear shall be the va lue selected fro m Tab le 707 ~3 or shall be determined from thc lesser of Formula (707-5) or Formul a (707-6).
B,. ~ 1070(1'", AI>
(707-5)
13,. = 0.12 A,l,·
(707-6)
Where the anc ho r bolt edge di stance hr in the direct ion of load is less than 12 bolt dia me le rs. Ihe va lu e of B•. ill
Formul a (707-5) shall be reduced by iinc
z.ero at .1Il he- d istance o f 40 mill. Where adj accllI anchors arc spaced closer th an 8th, the a ll owable shear of the adj acent a nc ho rs delCrmined by Formul a (707~5) shall be reduced by linear in terpolat ion to 0.75 ti mes the allowa ble shear va lue at a center-to-cen ter spacing of fo ur bolt diameters.
Nolional Structu ral Code of tile Philippines 6'" Edition Volume 1
7 -22
CHAPHT? 7 Ma.sonry
707.1.5.4 Combined Shear and Tension
707.1.8.2 Determination of Modulus of Elasticity
Anchor bolts subjected 10 combined s.hear and tension shall be designed in accordance with: h,
h,.
IJ,
IJ"
-·-+·····~1.0
(707-7)
The modulus of elasticity
or
each type
or
masonry in
composite construction shall be measured by tests if the modular ratio of the respective types of masonry exceeds 2 \0 I as determined by Sectio!] 706.2. I 2. 707.1.8.3 Structural Continuity
707.1.6 Compression in Walls and Columns 707.1.6.1 Walls, Axial Loads
Stresses due to compressive forces applied at the centroid of wall ·may be computed, assuming uniform dis.tribution over the effective area, by
f"
= PIA,.
(707-S)
707.1.6.2 Columns, Axial Loads
Stresses due to compressi ve forces appl led at the centroid of columns may be computed by Formula (707-8) assuming uniform distribution over the effective area. 707.1.6.3 Columns, Bending or Combined Bending and Axial Loads
Stresses ill columns due to combined bending and axial loads shall satisfy the requirements of Section 707.2.7 where j;/Fo is replaced by PIP". Columns subjected to bending shall meet all applicable requirements for flexural design. 707.1.7 Shear Walls, Design Loads
When calculating shear or diagonal tension stresses, shear walls which resist seismic forces in Seismic Zone 4 shull be designed to resist J.5 times the forces required by Section 20SS. 707.1.8 Design, Composite Construction
707.1.8.3.1 Bonding of Wythes All wythes of composite masonry clements shall be tied together as specified in Section 706.1.5.2 as a minimum requirement. Additional tics or the combination of grout and metal tics shall be provided to transfer the calculated stress. 707.1.8.3.2 Material Properties The effect of dimensional changes of the various materials and different boundary conditions of various wythes shall be included in the design. 707.1.8.4 Design Procedure, Transformed Sections
In the design of transformed sections, one materia! is chosen as the reference material, and the other materials arc transformed to an equivalent area of the reference material by mUltiplying the areas of the other materials by the respective ratios of the modulus of elasticity of the other materials to that of the reference material. Thickness of the transformed area and its distance perpendicular to a given bending axis remain unchanged. Effectivc height or length of the clement remains unchanged. 707.1.9 Reuse of Masonry Units The allowable working stresses for reused masonry units shall not exceed 50 percellt of those permitted for !lew masonry units of the same properties. 707.2 Design of Reinforced Masonry
707.1.8.1 General
The requirements of this section govern masonry in which at least Olle wythe has cOIllPosition characteIistics different from the or wythes and is adequately bonded to act structural elemcnt.
multi-wythe strength or other wythe as a single
The following assulllptions shall apply to UK design of composite masonry: 1.
Analysis shall be based on elastic transfolll1cd section of the net area.
2.
The maximum computed stress in any portion of composite masonry shall not exceed the allowable stress for the material of that portion.
707.2.1 Scope The requirements of this section arc in addition to the requirements of Sections 706 and 707.1, and govern masonry in which reinforcement is lIsed to resist forces.
Walls with openings used to resist lateral loads whose pier and beam clements arc within the dimensional limits of Section 708.2.6. J.2 may be designed in accordance wi til Section 708.2.6. Walls llsed to resist lateral loads not meeting the dimensional limits of Section 708.2.6.1.2 may be designed as walls in accordance with this section 0,' Section 708.2.5.
Association of Struc~ur81 Engineers of the Philippines
CHAPTEJl ., . Masollry
707.2.2 Heinforc('.mcnt 707.2.2.1 Mnximulll Hcinforccmcnt Size
The maximulll size of reinforcement shall he 32 111111. Maximuill reinforcement area in cclIs shall be 6 percellt of the ce Jl area withollt splices and 12 perCCll! or th e <-:ell area with spli ces.
707.2.2.2 Cove,. All reinforcing bars, except joint reinforcclllclll, sha ll be completely embedded in mortar or grout and have II minimum cover, including the masonry unit, of at lca ~t 20 mJll, 40 nun of <..:over when the masonry is ex posed to wea ther and 50 mill of cover when the masonry is exposed to soi l. 707.2.2.3 Development Length The required dcvelopment le ngth I" for dc formed hars or t1cformcd wire shal! be cllkulated by:
I" = 0.29 d,,/s for bars in tension
I" = 0.22 d'i/: for bars in compression
(707 ·9) (707-10)
Devel opment length for smooth bars shall be twi ce thc length determined by Formula (707~9).
707.2.2.4 Reinforcement Bond Stress Bond stress u ill reinforcing bars shall not exceed th e following: Pl ain Bars 4 10 kPa Deformed Bars 1370 kP" Deformed Bars without kPa ~~~ In spectio~ _ __.__ - - -690 --------
707.2.2.5 Hooks 1.
The term "standard hook" shall mean one of th e following: 1.1 A 180-degree turn plus extension of at least 4 bar diameters, but not less than 63mm at rrec end of bar.
2.
!-2~
J . Inside diameter or bend for 16 mm or smalkr stirru ps and tics shall not be less than four bar diameter. Inside diame[c-l' of bend for 16 mill or larger stirrups ,Illd ties shall not be less than that sct f01111 in Table 7117·4. 4.
Hooks shall not be permitted ill the tensio n portion of any beam, except at the ends of simple or cantilever beams or at the freely supported end of co ntinuous or
restrained
bC,llHS.
5.
Hooks shall not be assumed to carry a load which would produce a tensile stress in the bar grea ter than 52 MPa.
6.
Hooks shall not be considered effecti ve in adding to the cO lupressivc resistance of bars.
7.
An y mcchani cal device c:lp,-I blc of developing. the st re ngth of the bill' wit ho llt damage 10 the masonry may he used in lieu of a hook . Data mu st be presented 10 show the adequacy of such devi ces.
707.2.2.6 Splices The amount of lap of lapped splices sha ll be sufficient to transfer the allowable stress of th e reinforcement as spec ified in Seclions 706.3.4. 707.2.2,3 and 707.2.12. In no case shall the length of the lapped splice be less than 30 bar dia meters for compression or 40 bar diameters for tension. Welded or mechanical connec ti ons shall develop 125 percent of the specified yield stre ngth of the bar in tension . £rceptioll:
For compressiotl bars itl columns lhat are ItOI parI of (h e seismic-resistillg system and are !lot subjec f 10 flexure, ollly III ; compJ'(~.HiI}e slrength Iwed be developed.
When adjacent spJices in grouted masonry are separated by 76 mill or Jess, the required lap length shall be increased 30 percent. Exception: Wh ere lap splices are staggered at leas! 24 bars diameters, in crease ill lap length is required.
110
incrcase~.
1.2 A 90-degree turn plus c:xtension of al least 12 bar diameters at free end of bar.
Sec Secti on 707.2.12 for lap splice
J.3 For stirrup alld ti e anchorage o nl y, e ithe r a 90degree o r a J 35-degrce tum , plus an ex tension o f at least six hal' dimllcters, bUI nol less than 65 mm at the free end of the hal'.
707.2.3 Design Assumptions The followin g (Issumptiolls
Inside diamete r of bend of the ban" other th an for stirrllps and ti cs, shall not be less than that set forth in Table 707-4
!.
Maso nry ca rries no tens ile stress.
2.
Reinforcement is completely SlII'l'ounded by and bonded to masonry material so th at they work together as a homogenolls material within the ran ge of allowable working stresses.
Nationa! Structura l Code of the Ph il ippi nes 6
th
Edition Volurne 1
e IMP'1 EFI 7 Masonry
7·24
707.2.4 Nonrcctangular Flexural El ements Flcxunll cleme nl s of nonrccla ngular cross see lion sh all IJ...~ designed ill
Secli ons 707. 1.4 and 707.2.3.
Where shear reinforcement desi gned to lake emirc shear fo rce is provi dcu. the ullowahlc shea r siress. in Ile XUf .d me mhe rs is:
r,.
I'~. :::: O. 25~ , 1.0 MPa maximuJll
(707 -I H)
707.2.5 Allowable Axial Compressive Stress and Force
For members other than reinforced masonry columns, th e allowable axia l compressive stress I;~, shall be determined as follo ws:
I:;' =0.25!'... II_(~)2 J
Stress in Shear Walls
Where inplan e fl exural reinfo:~celllenl is provided an d masonry is used to resist all ~jiLar, th e a ll o wHb le slw ,~r slress Fv in shear wall is:
M F, =1/36 (4- -M ),;-f' (80 -45 - ·) ma x. imulll , Vd /11 Vel
r" 99 I';,
Sh(!~lr
(707 - 11 )
140r
for h 'I
707.2.9 Allowable
(707-19)
= 0.25!'".c,~,rr
(707-12)
For M /Vd ~ I, r~,
; ; 1/12 ~
, 240 kPd max.im um (707- 20)
for h'lr > 99
For re inforced
masonry co lumn s, the .a llowab le axial
co mpress ive fo rce P" shall be detcnllin cd as follows:
I;,
= 10.25!, ...
A, +0 65A,F"J[{ I~~r
r J
(707-1 3)
J
(707- 14 )
for h'lr> 99
707.2.6 Allowable Flexural Compressive Stress The allowabl e f1 exura l compressive stress F,! is:
F" = 0.33!,,,, ' 13.8 MPa maximum Compressive
J'---
maximum
(707-2 1)
70r
707.2.7 Combined
IS
Fo r MIVd < J,
F , =1/24(4- -M ) f' (120-45 -M ) , Vel m. Vel
for h'lr " 99
P" = /0 25!, ... A,. +0.65A, F" ]( T
Where shear rein forceme nt desi gned ( 0 t;'lke .111 Ihe shear provided, the allowa ble shear stress F,., in ShCM wall s is:
Stresses,
(707-15)'
Unity
Formula Elements subjected to combined axial and flexural stresses shall be design ed in accordance with accepted principles of mechanics or in accordance with Formula (707~16): (707 - 16)
707.2.8 Allowabl e Shear Sln'ss ill Flcxuml Members Wbere no shear re inforcement is pl ovided, the allowable jll ncxural members is:
shear stress F,.
r-;, =a.083!!,,,;·, 345 kPa maximum
M / Vd " I, F,. = O. 12~ ,520 kPa maximulll (707-22 ) 707.2.10 Allowable Bearing Siress When a member bcar5 on the ful! area of cle ment, the allowabl e heari ng stress Fllr is: I~" =
masonry
(707-23 )
0.26['",
When a member bears of! one thi rd or less e le ment, the allowable bearing stress F"r is:
11
or a masonry (707-2'1)
Formula (707~24) applies only when th e least dimensi
(707-23) and (707·24).
(707-17)
Exception: For a distaltce of 1116 tlie clear span beyond rhe point of inflection, th e maximum stress shall be 140 kPa.
Association of Structural Engineers of the Phi lippines
or Formulas
CHAVITH"1 .
707.2.11 Allowahk' Stresses in Rcinf()IT('mcnt '1l 1 {~ ;d low;lhlc s tresscs ill rci nfon:clllclll shall hc as follows : 1.
T(~nsilc
Stress
1. 1 Deformed hal's, J;~,:::::
0.5;;- , Ie») MPa maximulll
(707-25)
J.2 Wire reinforcement ,
f~r::::: 0.5!y \ . 200 MPa ma xi muill
(707-26)
1.1 Tics, an chors li nd s mooth bars,
F,,::::: OAf;. , 140 MPa maximum
r\~ilSO!lry
;·2:)
707.2.14.2 Walls, Bending or Combined Bending and Axial Loads Stresses in walls du e to combined bending and ax ial loads shall satisfy thc requirements of Section 707.2.7 where);, is givcn by Formula (707 . 8). Wall s subjected to bending with or without ;Ixiallo
(707 -27) 707.2.15 Flexural Design, Rectangular Flexural
2.
Compressive Stress
2.1
Dcf()rrn~d J;~,_ :::::
bars in columns,
0.4/;. , 165 MPa maximum
(707-28)
section. I. Co mpress ive stress ill the masonry:
2.2 Deformed bars in flexural members,
Fl
:::
O.5 J.~.
, 165 MPa ma ximum
(707-2Y)
23 Deformed bar~ in shear walls whidl are confined by lateral tics throu gho ut the distance where compression reinforce ment is required and where sllch l
l:',.c= O.4/;. ,165MPamaximum
Elements Rectangular clements shall be designed in accordance with the rollowing formulas or othcr meth ods based o n the assumptiolls g iven in Sect ion s 70 7. 1.4, 707 .2.3 and this
(707-30)
707.2.12 Lap Splice increases In region s of moment where the design tensile s tresses in thc reinforce ment are greatcr than 80 percent of (he allowable steel tensile stress r" the lap length of splices shall be increased /lot less than .)0 pen.~e n( of the minimum required length . Other equivalent means of stress transfer to accomplish the same 50 percent increase may be used.
707.2.13 Reinforcement for Columns Columns shall be provided with reinforcement as specified in (his section . 707.2.13.1 Vertical Reinforcement The area of vertical reinforcement shall not be less than 0.005 A.. and 110t more than (l.()4 AI". A t le.}st four 10 n1l11 bars shall be provid ed . The minimulll clear distan ce be tw ee n panlll ei bars in columns shall be IwO and one half times the bar diameter.
M 2 /Jd 2 ik
~, =.~-(- )
.,
(707-3 1)
2.
Tensile stress in the longitudinal reinforcemeJll:
3.
/' = A'd ,J Design coefficients:
M
k
=.fi~~;)2 + 2111' - "l'
(707 -32)
(707-33)
or (707-34)
k
' i= 1- -
(707-35)
3
707.2.16 Bond of Flexural Reinforcement In flexural members ill which tensile reinforcement is paJ"<\!JC! to the compressive facc, the bond stress shall be computed by the form ul a : V
Ii
= -.--
["i d
707.2.14 Compression ill Walls and Columns
707.2.14.1 General
Stresses due to compressive forces in walls and columns shall be calculated in accordance with Section 707.2,5.
National Stl'Llctural Code of the Philippines 6
th
Edition Volume 1
(707-36)
1·26
CI,APTfli?
Masonry
707.2.17 Shear in Flexuntl Membtrs and Shear Walls
The shear stress in flexural members and shear walls shall be computed by;
CI():
,,~,
.'J
(707-37)
7()7.3.5 Allowahle Tellsile Stress Resultant tensile stress due [0 cOlllbined bending and aXI load shall not exceed the allowable nexural tensile :;(1'cs.-; , F/.
For members or T or I section, tJ' shall be substituted for b. Where j.. as computed by Formula (707-37) exceeds the allowable shear stress in masonry, F,., web reinforcement shall be provided and designed to carry the total shear force. Both vertical and horizontal shear stresses shall be considered.
The allow;~blc tensile stress for walls in flexure \'.~ ! ho\l: tensile reinforcement using portland cement and hydrated lime, or using mOI1ar cement Type M or S Jllol1ar, sbl! n<'! exceed the values in Table 707-5.
\I
bjd
The
area
required
for
shear
reinforcement
placed
perpendicular to the longitudinal reinforcement shall be
computed by: A,.
(707-38)
Where web rcinforccment is required, it shall be so spaced that every 45~degree line extending from a point at d/2 of the beam to the longitudinal tension bars shall be crossed by at least one line of web reinforcement.
Values in Table 707-5 for tension nOfmalto head joints ;n-!' for running bond; no tension is allowed across head ill stack bOlld masonry. These values shall not be 0:-.','0 horizontal flexural members. 707.3.6 Allowable Shear Stn'ss in Flcxural Members The allowable shear stress Fv in flexural members is:
l~. = tl083JY:~, 345
kPa maximuill
Cl(:-·'
Exception: For a distance of 11/6 111 the clear .\pan beyond fhe p( it(fleCfiofl, fhe maximum slress shall be /38 kPa.
if)! ;',"
707.3 Dcsign of Unrcinfol'ccd Masonry 707.3.1 Gelleral The requirements of this section govern masonry in which reinforcement is not used to resist design forces and arc in addition to thc requirements of Sections 706 and 707.1
707.3.7 Allowable Shear Stress ill Shear Walls The allowable shear stress Fv in shear walls is as follo\\ .;: I.
P,
~0.25Fm
f~
is:
[1-(_h'_)'J forh'/r$99
(707-39)
140,.
(707-40)
707.3.3 Allowable Flexural Compressive Stress The allowable Ocxural compressive stress Pi, is:
Ph
~
0.33Fm .
14 MPa maximum
707.3.4 Combined Compressive Strcsses, FOl'mula
,
2.
Concrete units with Type M or S mortar, F,. maximum.
::::23~)
U\,
3.
Concrete units with Type N monar, F,. :;: maximum.
J 60
kPa
4.
The allowable shcar stress in unreinforced may be increased by 0.2/lIId .
m:: ' ·_)f1~·· ·
707.3.2 Allowable Axial Compressive Stress.
The allowable axial compressive stress
F;, ::::: (J.(J25~, 550 kPa maximum
707.3.8 Allowable Beariug Stress When a member bears on the full area of a element, the allowable bearing stress Fhl' shall be: FII(:;:
(707-41) Unity
Elements subjected to combined axial and flexural stresses shall be designed in accordance with accepted principles of mcchanics or in accordancc with the Formula (707-42):
0.26/'1II
When a member bears 011 one-third or less of a clcmcnt, the allowable bearing stress h" shall be:
n"
FiJI::: 0.38/,,,,
Formula (707-46) applies only when Ihe leasl
Association of Structural Engineers of tile Philippines
CHAPTU17
concentric area greater than olle third but less than the full area shall be interpolated between the values of Formulas (707 -4.1) and (707-46). 707.3.9 Combined Bending and Compressive Stresses
Axinl
Loads,
Compressive stresses due to combined bending and axial loads shall satisfy the requirements of Section 707.3.4. 707.3.10 Compression in Walls .md Columns
Stresses due to compressive forces in walls and columns shall be calculated in accordance with Section 707.2.5.
Stresses due
(0
flexure shall not exceed the values given in
Sections 707.1.2, 707.3.3 and 707.3.5, where:
ii, = M,.I!
(707-47)
707.3.12 Shear in Flexural Members and Shear Walls Shear calculations for flexural members and shear walls shall be based on Forllluia (707-48).
J,.
= V / A,.
7·??
S~CTIQN708 , ' .' .:' ;"N>',''''
'"
STRENGTH DESIGN Q:ifMA,SONRY 708.1 General 708.1.1 General Provisions The design of hollow-unit clay and concrete masonry structures using strength d~sig!l <;hall comply with the provisions of Section 706 and this section. EJ.:ception: TlVo-wythe solid-unit maso!l1)' may 708.2.1 and 708.2.4.
707.3.11 FlexlIral Design
MasollfY
b(~
used under Sections
708.1.2 Quality Assurance Provisions Special inspection during construction shall be provided as set forth in Section 1701.5, Item 7 of UBe. 708.1.3 Required Strength The required strength shall be determined in accordance with the factored load combinations of Section 203.3.
(707-48)
707.3.12 Corbels
The slope of corbelling (angle measured from the horizontal to the face of the corbelled surface) or unreinforccd masonry shall not be less than 60 degrees.
708.1.4 Design Strength Design strength is the nominal strength, multiplied by the strength-reduction factor, $, as specified in this sectioll. Masonry members shall be proportioned such that the design strength exceeds the required strength. 708.1.4.1 Beams, Piers and Columns
The maximum horizontal projection of corbelling from the plane of the wall shall be such that allowable stresses are not exceeded.
708.1.4.!.l Flexure
707.3.13 Stack Bond
Flexure with or without axial load, the value of 4) shaH be determined from Formula (708-1):
Masonry units laid in stack bond shall have longitudinal reinforcement of at least o.0002f times the vertical crosssectional area of the wall placed horizontally in the bed joints or in bond beams spaced veI1icaily not more than 1.20111 apart.
(708-1 )
and 708,1.4,1.2 Shear Shear: ¢ = 0.60
708.1.4,2 Wall Design for Out-of-Plane Load 708.1.4.2.1 Walls with Factored Axial Load of 0.04/,,,, or less Flexure: ¢ = 0.80. 708,1.4.2,2 Walls with Factored Axial Load Greater than 0.04 /'m Axial load and axial load with flexure: ~ = 0.80. Shear: 0.60.
National Structural Code of tile
Philippin~s 6'"
E:dilion Volume 1
$=
1,213
CI'lJ\F)T[n?
M;-lS()llIY
708.1.4.3 Wall Design for in-Plane Loads
70S.1.5 Anchor Bolts
708.1.4.3.1 Axial Load
70S. 1.5. I Required Strength
Axial load and axial load with flexure:
4) = 0.65.
For walls with sYlllmetrical reinforcelllent in which .I~, does not exceed 4 I:) MPa, (he value of may be increased linearly (0 0.85 as thc valuc of P" decreases from 0.1 () I'III A,. or 0.25 f\ to i'.crn.
The, required strength of embedded anchor boilS shal! bc determined from factored loads as specified in Section 70S.I.5. 708.1.5.2 No-ninal Anchor Bolt Strength
The nominai sirength of anchor bolls limes the strengthreduction factor shall equal or excced the required strength.
For solid grouted walls, the valuc of P" lllay be calculated by Formula (708-2) (708-2)
The nominal tensile capacity or anchor bolts sbaH be determined from the lesser of Formula (708-S) or (708-6). B'/I
where: 111, :::::
O.85d {e"," / /e"",
-I-
((,.I !~~)]}
::;;O.084Ap~
(708-3)
(708-5) (708-6)
708.1.4.3.1 Shear Slrear:
~
0.60.
The value of 4J may be 0.80 for any shear wall when its nominal shear strength exceeds the shear corresponding to development of its nominal flexural strength for the factored-load combination.
708.1.4.4 Moment-Resisting Wall Frames
The area AI' shall be the lesser of Formula (708-7) or (708-8) and where the projected areas of adjacent anchor bolts overlap, the value of All of each anchor bolt shall be reduced by one half of the overlapping area. A"
= hJ 1(
AI' = 1C 1,,/
708.1.4.4.1 Flexure With or Without Axial Load
~
Pf( 0.85- 2 (---) An/'m
708.1.4.4.2 Shear Shear: '" ~ 0.80. 708.1.4.5 Anchor Anchor bolts: '"
~
0.80.
708.1.4.6 Reinforcement 708.1.4.6.1 Development
(708-8)
The nominal shear capacity of anchor bolts shall be determined from the lesser of Formula (708-9) or (708-l 0). (708-9)
The value of shall be as determined from formula (7084); however, the value of
¢
008-7)
(708-4)
(708-10)
Wherc the anchor bolt edge distance, 1"<,, in the direction of load is less than 12 bolt diameters, the value of BII! in formula (808-9) shall be reduced by linear interpolation to zero at an he distance of 38 1111ll. Where adjacent anchor bollS arc spaced closer than 8th, the nominal shear strength of the adjacent anchors determined by Formula (708-9) shall be reduced by linear interpolation to 0.75 times the nominal shear strength at a centeHo-center spacing of four bolt diameters. Anchor bolts subjected to combincd shear and tcnsion .';l1all bc designcd in accordance with Formula (708-1 I).
Development: '" ~ 0.80.
(70SII)
708.1.4.6.2 Splices Splices:
~
0.80.
708.1.5.2 Anchor Bolt Placement Anchor bolts shall be placed so as to meet (he rdr,c distance, embedment depth and spacing rcquircmc.ll; Jf Sections 706.2.14.2, 706.2.14.3 and 706.2.14.4.
Association of Structural Engineers of tile Philippines
70R.2 n.cinfon·cd Masonry
paralic! to the Dl'utl'al axis at a distancl' a ::: O.X5l· rrorll till' fiber or maximuill (omprcssivc strain. Distanc e c from filwr or max imulll strain to (he neutral axis shall bl' Illca..-ured in a direct ion perpend ic ular to that ax is.
708.2.1 Gene,",,1 70S.2.1.1 Scope The requi rements of this sect ion arc in addition to the rcquircmcrlls of Sections 706 and 70M. I and govern m;:lsonry in which reinforcemcnt is used to res ist rorces.
The following assumptions appl y: Masonry carries no tensile
~trcs s
708.2.2.1 Maximum ncinforcclIlent
The maximum si ze o r rci ll forc cmcill shall be 28 mill. The diameter o r iJ bar shall not exceed on e fourth th e least dimcns'iull or it cell. No more than two bars shall be placed in a ceii oj' a wa!! or a wall frame.
708.2.1.2 Design Assumptions
of
708.2.2 neinfun:emcllt Requirements and Details
greater than the modulus 708.2.2.2 Placement
I1!plUi'C.
The place ment of reinforcement shall compl y with th e Reinforcement is completely surrounded by and bonded to masonry matclial sO that they work together as a homogeneous material . No minal strength of singly reinforced masonry waH cross sections for combined Ilexure and axial load shall be based on applicable conditi ons of equilibrium and compatibilit y or stmins. Strain ill reinforcemeJlt and maso nry wall s shall be ass umed to be directly proportional to the di stance from th e neutral axis.
Maximum usabl c strain, enllO , at Ole extreme masonry cOlllpressioll nber shall : J.
be 0.003 for the design of beams. piers. columns and walls.
2.
not exceed 0.003 for mom ent-resisting wall frames , unl ess lateral reinforcement as defined in Sec tion
fOllowin g:
In columns and pi ers, the dea l di stance helwccil vcrti cal reinforcin g bars sh all not be less than one and one-half lime s the nomina l bil!' diameter. nor less than 40 mm. 708.2.2.3 Cover All reinforcin g bars shall be completely embedded in monar or grout and shall ha ve a co ve r of not ICss than .18 mm nor Jess th
I,
A 180·degrce turn plu..- an extension of
2.
A I 35 ·degree turn pi US an extensioll diam eters at the free end of the bar.
Strain in reinforcement and masonry shall be assumed (0 be directl y proportional to the distan ce from the neutral axis.
3.
A 90-degree turn plus an exten sion of at least 12 bar diameters at the free end of the bar.
Stress in reinforcement below specified yield strength f;· for grade of reinforcement used shall be taken as E~f times steel st rain. For strains greater than that corresponding to J;., stress in reinforcement shall be considered indepcndent of st rain and equal to1;..
708.2.2.5 Minimum Bend Diameter for Reinforcing Bars
Diameter of bend measured on the inside of a bar other th
T ens ile strength of masonry walls shall be neglect ed ill fl ex ural calculation of strength, except when computing requirements for deflection.
Inside diameter of bends for sti rrups and lics shall not be less than 4(", for 16 mill bars and smaller. For bars larger than 16 mm di ameter of bend shall be in accordan ce with Tabl e 707-4
708.2.6 .2.6 is lHili zed.
Relationship between masonry compressive stress and masonry strain lIla y be assumed to be rectan gular as defined by the following: Masonry stress of 0.85 I'm shall be assumed uniformly di stributed over an equivalent compression zone bounded by edges of the cross section and a straight line located
or at
least six bar
708.2.2.6 Development The calculated tension or compression reinforcement shall be developed in accordance with the following pro visions: The embedment length of reinforcement determined by Formula (708-12).
111
National Structural Cod e of the Philippines 6 Edition Volume 1
shall
be
730
CHAI'TEI11
Masonry
008-12) where;
(70S- J})
708.2.3.3 Balanced Reinforcement Compression Limit Statf.'.
I.
The distribut io n of strain across th e sectio!) shall be assumed (0 vary linearly from the maximum usable strain, e"III' at th e extreme compressio n fiber of the element, to II yie ld strain of fiE"~ at the ex treme tensioll fiber of the clement. ..
2.
Compression fo rces shail be in equili brium with the sum of tcns io n fo rces in the reinforcement and lhe maximum ax ial load associated with a load ing combinati on I .OD + I .OL + ( I AE or 1. 3 W).
708.2.2.7 Splices
Reinforcement splices shal! comply with one of the followin g:
I.
The minimum length of lap for bl:lrs shall be 300 or the length determined by Formula (708~J 4).
2.
',= '",./¢'
Illlll
(708· 14)
Bars spliced by non,contact lap sp lices sha ll be spaced transversely a distance not greater than one fifth th e required length of lap or more than 200 rnm.
2.
3.
for
Cilcullili on of the b.li<.lllced reinrOrtT IllCIl1 ratio, PI" shall be b'lsed on the following assu mption s:
K shall 1101 exceed Jd". The minill lulll embedment Icngtll o f' reinforceme nt shal l he 300 Illlll .
Ratio
1. The reinforcement shall be assum ed to be uniformly distributed over the depth of the clemen t and the. balanced rei nforcement ratio shal l be calculated as th e area of this reinforce ment di vided by th e net :l rCll of the clemen t. 4.
A ll longitudinal reinforcement sha ll be included ill calcu lating the balanced reinforcement ratio except that the contribution of compression reinforcement 10 resistance of co mpressive loads shall not be considered .
A welded splice shall have the bars bu((cd and welded to develop in tension 125 perce nt of the yield strength of th e bar.!,..
708.2.3.4 Required Strength
Mechanical splices shall have the bars connected to develop in tension Of compress ion, as required , al least 125 percen t of the yield strength of th e bar.f,..
Except as req uired by Sections 708.2.3.6 thro ugh 708.2.3. 12, the requi red strengt h shall be determi ned in accordance with Secti on 708. 1.3.
708.2.3 Design of Beams, Piers and Columns 708.2.3.1 General The requirements of thi s section are for the design o f masonry beams, piers and columns.
The value of /,,,, shall not be less than 10 MPa. For computational purposes, the value of/,,,, shall not exceed 28
MPa. 708.2.3.2 Design Ass umptions
Member design forces shall be based on an analysis whi ch considers the relati ve stiffness of structural members. The calcu lation of lateral stiffness shall include (he contribution of all beams, piers and columns. The effects of cracking on member stiffness shall be considered . Thc drift ratio of piers and columns shall sati sfy the limits specified in Chapter 2.
708.2.3.5 Design Strength
Design strength provided by beam, pier or column cross sec ti ons in terms of axia l force, shear and momen t shall beco mputed as the nominal strength multiplied by the applicable strength -redu ction factor, cpo specified in Secti on 708. 104. 708.2.3.6 Nominal Strength 708.2.3.6.1 Nominal Axial and Flexural Strength Thc nomina l axial st rength. P", and th e nomi na! n ex u r~d stre ngt h. M", of a cross' secti on s hall be determ ined ;;\ accord ance wit h the design i\SSlimpt ions or Secti on 708.2.1.2 an d 708.2.3.2.
The maximum nominal axial compressive strength shall be determined in accorda nce with Formula (708- 15). p" = 0.8010.85/,,,, (A, - A ,) +fA,]
(70S-lS)
708.2.3.6.2 Nominal Shear Strength The nomi nal shear strengt h shal l be
(708-16)
Associatior: of Structural Engineers of the Philippines
CHAPTEn l · l\1asonry
whe re:
Exception: (708· 17)
and
/·31
V, = A,P,J;.
(708· I8)
Where seismic loads are derermill ed bfJSed 011 Rw 1101 greater than three and where all joirus satisfy the provisions of Section 708.2.6,2.9, the piers may be used to provide seismic load resistance.
708.2,3.6.2 Nominlll Shellr Strength
708.2.3,9 Dimensional L,imits
The nominal shear strength shall be:
Dimcnsions shall be in accordance wi th th e following:
1.
Thc ' nominal shear strength shall not exceed the value given in Table 708· I.
2.
The va lue of V"' shall be assumed to be zero within any region subjected to net tension factored loads.
3.
The va lue of V", shall be ass umed 10 be J 70 kPa where M is greH1c r th.Ul 0.7 Mil" The required momen!. Mil> " for seismic design for compa rison with the 0.7 M" V,\)u c of this section shall bc based on an R ... of 3.
J.
Beams
1.1 Thc nominal width of a beam shall not he
le~s
than 150
mm . 1.2 The clear di stance between local ions of laleral bracing of the compression side of the beam shall not exceed 32 timcs thc leasl width of the compression area. 1.3 The nominal depth of a bea m shall not be less than 200 m ill.
708.2.3.7 Reinforcement
I.
2.
Piers
Wh ere transverse reinforcement is required, thc maximum spacing shall not exceed one half the depth of th e member nor J 200 mm.
2. 1 The nominal width of a pier shalinOl be less than 153 mill and shall !lot exceed 400 mill .
2.
Flex ural reinforcement shall be uniformly di stribut ed througho ut th e depth of the clement.
3.
Flexural clements subjected to load reversals shall be symmetricall y reinforced.
2.2 The distance between lateral supports of a pier shall not exceed 30 times the nominal width of the piers except as provided for in Section 708.2.3.9, Itcm 2.3.
4.
The no mi na l moment strengt h at any sec tion along a member shall not be less than one fourth of the maxi mum momcnt strength.
S.
The flex ural rei nforcement rat io, p, shall not exceed 0.5 Ph.
6.
Lap splices shall comply with rhe provisions of Secti on 708.2.2.7.
7,
Welded splices and mechanical splices which develop at leas t 125 percent of tile specified yield strength of a bar may be used for splicing the reinforcemcnt. Not more than two longitudinal bars shall be spliced at It section. The distance between splices of adjacent bars shall be at least 750 mm along the longilUdinai axis.
8.
Specified yield strength of reinforccmcll! shall not exceed 415 MPa. The actual yield st rengt h based 011 mill tcsts shall not exceed 1.25 times the specificd yield st rength.
708.2.3.8 Seismic Design Provisions
The lateral seismic load resistance in any line or story level shall be provided by shear walls or wall frames, or a combination of shear walls and wall frames. Shear walls and wall frames shall provide at least 80 percent of the lateral stiffness in any line or story level.
2.3 When the distance between lateral supports of a pier exceeds 30 times the nominal width of 1he pier, the provisions of Section 708.2.4 shall be used fo r design. 2.4 The nominal lenglh of a picr shall not be less than three tillles the no minal width of lhe pier. The nomi nal length of a picr shall not be greater tha n six times thc nominal width of the pier. The clear height of a pier shall not exceed fi ve tin1es the nomina l length or the pier. Exception: The length of a pier may be equal to the width of the pier wh en the axial force at the location of maximum moment i.'f
less than 0.04 f 3.
m
A,.
Columns
3.1 The nomina! widt h of a column shn Jl
l10t
he less th an
300 mill. 3.2 The di.'ilance bet ween lateral supports of" colullllI shall not excced 30 times Ihe nominal widt h orlhe column , 3.3 Thc nomina l lengt h of a CO)UIIl Il shall not be less th an 300 n1ln an d not greater th an threc tim es the nomi nal width of the column.
National Structural Code of th o Pililippincs 6'" Edition Volume 1
7<32
CHAI'TUl 7 . Masonry
708.2.3.10 Bellms 708.2.3.10.1 Scope Members designed primarily to resist flexure shall comply with the requirements of this section. The factored axial compressive force Oil a beam shall not exceed (LOS A,I'm. 708.2.3.10.2 Longitudinal Reinforcement
708.2.3.1 1.3 Transverse Udnforcement Transverse reinforcement shall be provided where V exceeds VII!' Required shear, VII' shall include the effects of drift. The vllluc of VI< shall be based on LlM . When transverse shear reinforcement is required, the following provisions shall apply: I.
Shear reinforcement shall be hooked around the extreme longitudinal bars with' a 180~degree hook. Alternatively, at wall intersections, transverse reinforcement with a 90-degrcc standard hook around a vertical bar in the intersecting wall shall be permitted.
2.
The minimum transverse reinforcement ratio shall be 0.0015.
J. The variation in the- longitudinal reinforcing bars shall 110( be greater than one bar size. Not more
li~an two bar
sizes shall be used in a beam.
2.
The nominal flexural strength of a beam shall not be less than 1.3 times the nominal cracking moment
strength of the beam. The modulus of rupture, f" for this calculation shall be assumed 10 be 1.6 MPa. 708.2.3.10.3 Transverse ReinfOl'Cemcnt Transverse reinforcement shall be provided where VI' exceeds Vm' Required shear, VI" shall include the effects of the drift. The value of VII shall be based on .dM . When transverse shear reinforcement is required, the following provisions shall apply:
708.2.3.12 Columns 708.2.3.12.1 Scope Columns shall comply with the requirements of this section.
708.2.3.12.2 Longitudinal Reinforcement Longitudinal reinforcement shall be.a minimum of four bars, one in each corner of the column.
1.
Shear reinforcement shall be a single bar with degree hook at each end.
2.
Shear reinforcement shall be hooked around the longitudinal reinforcement.
3.
The min. transverse shear reinforcement ratio shall be 0.0007.
I.
Lateral ties shall be provided in accordance wilh Section 706.3.6.
4.
The first transverse bar shall not be more than one. fourth of the beam depth from the end of the beam.
2.
Minimum lateral reinforcement area shall be 0.0018 A g .
J 80-
I.
Maximum reinforcement area shall be 0.03 Ac.
2.
Minimum reinforcement area shall be 0.005 A.,.
708.2.3.12.3. Lateral Tics
708.2.3.12.4 Construction
708.2.3.10.4 COllstruction
Columns shall be solid grouted.
Beams shall be solid grouted.
708.2.4 Wan Design for Out-of-Plane Loads
708.2.3.11 Piers
708.2.4.1 General
708.2.3.11.1 Scope
Piers proportioned to resist flexure and shear in conjunction with axial load shall comply with the requirements o/" this section. The factored axial compression on the piers shall not exceed 0.3 AJ'",.
708.2.3.1l.2 Longitudinal Reinforcement A pier subjected to in-plane stress reversals shall be longitudinally reinforced symmctrical!y Oil both sides of the neutral axis of the pier.
1.
Olle bar shall be provided in the end cells.
2.
The minimum longitudinal reinforcement ratio shall be 0.0007.
The requirements of this section are for the design of W,il is for out-of-plane loads.
708.2.4.2 Maximum Reinforcement The reinforcement ratio shall not exceed 0.5 p". 708.2.4.3 Moment and Deflection Calculations All moment and deflection calculations in Seclion 7(!; 7.L1 are based Oil simple support conditions top and b,'.. )In. Other SUppOI1 and fixity conditions, moments :tnd deflections shall be calculated using established principles of mechanics.
Association of Structural Engineers of the Philippines
708.2.4.4 Walls with Axial Load of 0.041'm
or
less
The nominal shear strength shall be determined by Formula (XOH -26).
The procedures SCI forth in thi s secti on, which c() ll ~ i dcr the slende rness of walls by represellting e ffe cts of Hxial forces
and deflection in cakul<11 ioll or moments, shall be used when the vertical load stress at the locat io n of maximum moment docs not exceed 0.04/'1II as comput ed by Formula (708- 19). The vaillc of!,,,, sha lillot excecd 40 MPa. P", + PI -----. < () 04 j" Ag _.
(7(i8-19)
III
(708-26)
708.2.4.6 Dellectlon Design
The mid-height deflcction, 6;, under service lateral and vertical loads (without load factors) shall be limited by the relation: (708-27)
6 , = 0.007 Ii Walls shall ha ve
minimum (hi ckncss of 150 111m.
P6 effec ts shall be included in deflect ion calculation. The
Required moment and axial force shall be det ermi ned at the mid -height of the wall and shall be used for design. The
midheight deflection shall be computed with the following formula :
fa clOrcd moment, M,,, .11 the mid·hcight of the wall sha ll be determined by Forliluia (708 20).
(708 -28)
v
M
It'
,,2
I'
- u ' P6. "--8+ p11/'2+ /I II
(708-20)
where:
(708·29)
Li/l ;:: deflection at mid -height of wall due to factored loads (708'-2 1)
The cracking momcnt strength of the wall shall be determin ed from the formul a: (708 -30)
M" = Sj',
The des ign st rength for out-of-plane wall loading shall be determined by Formul a (708-22)_
(708-22)
J.
where:
Mo = A"j,. (d - aI2)
A Jr = (AJ;. (J
Th e modulus of mplUre,J,. shall be as follows:
-I-
(708-2 3)
Pu}J;., effective are;'l of steel
(708-24)
II' =O.33..J1: 2.
=(P" + A,j,.) /0.85 I'", b, depth of stress bl ock due to factored loads (708-25)
708.2.4.5 Wall with Axial Load Greater than O.04['m The procedures set forth in this section shall be used for the design of masonry walls wh en the vertical load stresses at the location of maximum mome nt exceed 0.04/,,,, but are less [han 0.2/,,,, and the slenderness ratio h 'II docs not exceed 30.
Design strength provided by the wall cross secti on in terms of aXi al force, shear and moment shall be computed as the nominal strength multipli ed by the applic ab le strengthreduction factor,
For fully grouted hollow-unit masonry,
' 1.6 MPa maxim um
(708 -3 1)
For pal1iall y grouted hollow-unit masonry,
f" = 0.2 1.J1: . 0.86 MPa ma xi mum
(708-32)
3. For two-wythe brick masonry,
j,. = O.166..} I'm ,0,86 kPa
(708 -
maximum
33)
708.2.5 Wall Design for In-Plane Loads 708.2.5.1 General
The req uireme nts of this section are for the desi gn of walls for in-plane loads. The value of/'IIJ shall not be less than 10 MPa than 28 MP•.
National Structural Code of the Philippines 6'" Edition Volume 1
1101'
greater
7<34
CHAPlEH!· Masonry
3. 708.2.5.2 Reinforcement Reinforcement shall be in accordance with the following:
J.
Minimulll reinforcement shall be provided in accordance with Section 706.1.12.4, Item 2.3, for all seismic areas using this method of analysis.
2.
When the shear wall failure mode is in flexure, the nominal flexural strength of the shear wall shall bc at least 1.8 times the cracking moment strcngth of a fully grouted wall or 3.0 timcs the cracking momcnt strength of a partially grouted wall from Formula (708-30).
3.
4.
The amount of vertical reinforcement shall not be less than one half the horizontal reinforcement.
Spacing of horizontal reinforcement within the region defined in Section 708.2.5.5, Item 3, shall not exceed three tillles the nominal wall thickness nor 600 mm.
708.2.5.3 Design Strength
Design strength provided by thc shear wall cross section in terms of axial force, shear and moment shall be computed as the nominal strength Illultiplied by the applicable strength-reduction factor, ¢, specified in Section 708.1.4.3.
r:or all cross sections within the region defined by the base of the shear wall and a plane at a distance L". above the base of the shear wall, the nominal shear strength shaH be determined from Formula (708-39). (708-39;
The required shear strength for this region shaH be calculated at a distance L,,/2 above the base of the shear wall, but not to exceed one half story height. For the other region, the nominal shear strength of the shear wall shall be determined from Formula (708-36). 708.2.5.6 Boundary Members Boundary members shall be as follows:
J.
Boundary mcmbers shall bc provided at the boundaries of shear walls when the compressive strains in the wall exceed 0.0015. The strain shal! be determined llsing factored forces and R". equal to i.5.
2.
The minimum length of the boundary member shall be three times the thickness of the wall, but shall include all areas where the compressive strain per Section 2108.2.6.2.7 is greater than 0.001 S.
3.
Lateral reinforcement shall be provided for the boundaryelcments. The latcral reinforcement shall be a minimum of 10 111m diameter at a maximum of 200 111m spacing within the grouted core or equivalent confinement which can develop an ultimate compressive masonry strain of at least 0.006.
708.2.5.4 Axial Strength
The nominal axial strength of the shear wal! supporting axial loads only shall be calculated by Formula (708-34). P" = 0.851'" (A,,·- A,J + J; A,
(708-34)
Axial design strength provided by the shear wall cross section shall satisfy Formula (708-35). P,,::; 0.80
Po
(708-35)
708.2.6 Design of Moment-Resisting Wall Frames
708.2.5.5 Shear Strength Shear strength shall be as follows:
1.
2.
For a shear wall whose nominal shear strength exceeds the shear corresponding to development of its nomin:tl flexural strength, two sheacregions exist.
708.2.6.1 General Requirements
The nominal shear strength shall be determined using cithcr Item 2 or 3 below. Maximum nominal shear strength values arc detemlined from Table 708-1. The nominal shear strength of the shear wall shaH be determined from Formula (708-36), exccpt as provided in Item 3 below
708.2.6.1.1 Scope The requirements of this section arc for the design of fully grouted moment -resisti ng wall frames constructed (,r reinforced open-end hollow~unit concrete or hollow·tini~ clay masonry.
(708-36)
where: (708-37)
and (708-38)
Association of Structural Engineers of the Philippines
CHAPTEn'1 . Maso nry
7·3:)
708.2.6.2,3 Dcsign Asslimption for Nominal Strength 708.2.6.1.2 Dimcnsional Limits Dimensions shall he in accordance with
lIH.~
following:
708.2.6.1.2.1 !loa illS Clear span for the beam shall not be less than two times its dcpth.
Tile nominal strength of member cross sections shall be bHscd on assulnptions pn;scribed in Section 708.2. J .2.
The valu e of ['lit shall not he less th an 10 MPa or greate r than 2H MPa. 708.2.6.2.4 Reinforcement
The nominal depth of lhe beam sha!! not be less than two units or 400 n1ln, wh ichever is greater. Th e no minal beam depth to nominal bCHIll width f
The nomin,,1 moment strength at any section along a
The nominal width of the beam shall he the great er of 2(X) mm or 1126 of the clear spall between pier fa ces .
Lu]> splices shall be as defined in Section 708.2.2.7. The center of the lap splice shall be the center of th e member clear length.
708.2.6.1.2.2 Piers The nominal depth of pi ers shall not exceed 2.4 m. Nominal depth shall not be less than two full units or HOO mm, wh ichever is gre.lIer. T he nominal wid th of' pi ers shall Ilot he less than the nominal width of th e beam, nO!' less than 2(X) mill OJ' 1114 or the clear height bel wee n beam faces, whichever is greater.
member shaH not be less tlwll one -fourlh of the highcr mOllle nl strength provided ill the two ends of the member.
Welded splices and mechanical connection conforming to Sec ti on 412.! 4.3. Item J throu gh 4 of UBC, may be used for splicing the reinforcelllenl al .my section provided not more than alternate longitudinal b:trs arc spliced at section, and the di stance between splices or alternate bars is at least 600 111111 along the longitudinal axis.
The clear height-to-dcpth ratio of pier shall not exceed 5.
Reinforcement shall not have a specified yield strength greater Ihan 415 MPa. The actual yield strength based on mill tes ts shall not exceed the specified yield strength times
708.2.6.1.2.3 AlIlllysis
1.3.
Member desi gn forces sha ll he the based 011 an analysis which considers the rel ative stiffness of pier and beam lllC!mbcr, includin g th e stiffening influence of joint s. The calculation or beam mOlllen! cap;l city for the determination of pier design shall include any contribution of floor slab reinforcement. The out-of-plane drift ratio of all piers shal ! sati sfy the drift ratio limits specified in Section 2-47. 708.2.6.2 Design Procedure 708.2.6.2.1 Required Strength Except as required by the Sections 708 .2.6.7 and 708.2.6,2.8, the required strength shall be determined in accordance with Section 708. J.3 708.2.6.2.2 Design Strength
Design strength provided by frame memb er cross sections force, shear and mom elH shall be c.omputed as the nominal strength multiplied by the applicable strength-redu ction factor.
108.2.6.2.5 Flexural Mem bers (Hearn) Requirements of this secti on apply !O beams proportioned primarily to resist flexure a ~ follows.
The axial compressive force on beams due to factored loads shall not exceed O. J 0 A,J'III. 1. Longitudinal Reinrorcement At any section of a beam, each masonry unit through the beam depth shall contain longitudinal reinforcement.
The variation in the longitudinal reinforcement area between units at any section shall not be greater than 50 percellt, except multiple diam . 12 bars shall not be greater Ihan 100 percent of the minimum area of longitudinal rei nforcement contained by an y one un it, except where splices occ ur. Minimum reinforcement ratio calculated over the gross
cross section shall be 0.002. Maximum reinforcemcnt rati o calculated over the gross cross section shall be 0.15 j'", / f,.
Members shall be proportioned such that the design strength exceeds the required strength.
National Stru ctu ra l Code of the Philippines 6'" Edition Volume 1
/<36
CHAPTEF! ? . Masonry
The minimuill transverse rcinfofCClllCrH ratio shall be
2.
O.O() I S
Transverse Ucinfor£'t'll1ent
Tran sverse rci llfon.:cmcllt shall be hooked arou nd top and hOIlOIll longilUdinal hilI's wit h
:-"ithin an end region extending one beam depth from pi cr
faces and at any region at which beam flexural yielding may occur during seismic or wind l()ad i nl~, maximuJll spacing or transverse reinforcement shall not' exceed one fOllJ1h the nominal depth of the bc;;m:
3. Lateral Reillfor'cclllcnt L ueral rein forcemen t shall be pro vided to coniine the grouted core when co mpressive strains clue 10 axial and bending forces exceed 0.0015, corresponding 10 factored forces with Rw equul to 1.5. The unconfined portion of the cross section with strain exceeding 0.0015 shall be neglected in computing the nominal strengt h of the sec tion. total cross·scct ionHI area of rectangul ar tie rei nforcement for the confined core shall not he less than :
Thc
The maximum spacing of transverse reinforcement shall not exceed one hal f the nominal depth of the beam. Minimum reinforce ment ratio shall be 0.00]5 The first transverse bar shall not be morc than 100 mm from the face of the pier.
708.2.6.2.6 Memuers Suujected to Axial Force and Flexure The requirements set fonh in this subsection apply to piers proportioned 10 resist flexure in conjuJlction with axi al loads.
1. Longitudinal Reinforcement A minimum of four longitudinal bars shall be provided at all sections o f every pier.
(708-40) Alternati vely, equivalent confinement which can develop an ultimate compressive strain of at least 0.006 may be substituted for rectangular lie reinforcemcnt. 708.2.6.2.7 I'ier Design Forces Pier nominal momCIll strength shall not be less than 1.6 times the pier moment corresponding to the development of th e beam plastic hin ges, cxcept at the foundati on level. Pier axial load based on the development of beam plastic hinges in accordance with the paragraph above and including factored dead an d li ve loads shall no t exceed 0.15 Anf'm·
Flexural rei nforcement shall be distributed across the member depth. Variation in reinforcement area between reinforced cells shall not exceed 50 percent.
Minimum rei nforcement ratio calcu lated over the gross cross seclion shall be 0.002 Maximum reinforcement ratio calcul ated over the gross cross seclion shall be 0.15 I'm ( /'"
Maximum bar diameter shall be one eight nominal width of
The drift rati o of piers shall satisfy the limits specified in Chapler 2.
The. effects of cracking on member stiffness shall be co nsidered . The base plastic hinge of the picr must form immediately adjacent (0 the leve l of Ialeral support provided at the base
or fou ndation.
the pier.
708.2.6.2.8 Shear Design.
2. Transverse Reinforcement
1. General Beam and pier Ilom in,ll she:\!· slrength shall not be less thlln 1.4 limcs the shears cOIH',sponding ( 0 the development of lhe fle xu ral yieldi ng.
Tran sverse reinforcement shall be hooked arou nd the extreme longitudi nal b.ars wi th stand ard 180-degree hook as defined in Secl ion 708 .2.2.4.
Within an end region ex tending one pi er dept h from the end of the beam, and at allY region at wh ic h fl exural yielding may OCCllr durin g seismic or wind loading, the maximum spacing of transverse reinforcement shall not exceed olle fourth the nominal depth of the pier. The max imulIl spacing of tran sverse reinforcemcni shall not exceed one half th e nominal depth of the pier.
It sha ll be assum cd in the calcu lation of mcmber shear force tllat moments of opposite sign act at the joint faces and that the member is loaded with the tributary gravi ty load along its span.
2. Vertical Memuer Shear Strength The nominal shea r s(renglh shall be determined from Formula (708-4 1).
Association of Structural Engineers of the Philippines
CHAPTER l . Masonry
(10X-41)
where: (708-42)
7·37
Picr longitudinal rcinfon:cmel1! tcrminating in a beam shall be extended to the fur face oj' thc bcam and an chored by a sumdard 90 or 180 degree hook, as defined in Section 708.2.2.4, bellt back to the beam.
and
2. Transverse Rcinforcemcnt (708-43) The vallie of II", shall bc zero within an end "cginn
extending one pier depth from beam fllecs and at any region where pier flexural yielding may occur during seismic loading. clOd at pi crs s ubj ected
Special horizontal joint shear reinforcement crossing a pote nrial corner to corner diagonal joint shear crack. and an chored by stf\lldard hooks, as defincd in Section 708 .2.2.4, around the ext re me pier reinforcing bars shall be pro vided suc h thtlt
nel lcns ioll fa c tored loads. The nominal pier shear strength, V,p 5h,,11 1101 exceed the 10
value determined from Table 708-1.
3. Beam Shear Strength The nominal shear strength shall be determined from Formula (708-44).
II",
= 001 A"".jT.,~
The value of \/m shnll be zero wit hin an end region
loading.
The nominal beam shea r strength, V,,, shall be dc1Crmined frol1l Formula (708-4 5).
Am"R.
Venical shear forces may be considered to be carried by a combination of masonry shear resisting mechanisms and tru ss mechanism involving intermediate pier reinforcing bars.
(708 -44)
extending one beam depth from pier faces and to any region at which beam fl exure yielding may occur during seismic
V'I '5:0.33
(708-48)
3. Shear Strength The nominal horizontal she ar strength of lbe joint shall not
exceed:
0.58..ff:: or 2.5 MPa, whichever is less.
·<~~~i~;~·~';";~.<:~~1~~r:~{lf7~ii~~~rltW~~~~~f~;~~1~~B1·~f~&.;;~~1~;
(708-45)
708.2.6.2.9 Joints
1. General Requircl11cllts Where reinforcing bars extend through a join t, th e joint dimensions shall be proportioned such thaI h, > 57827 d"" I f',
(708-46)
h, > 21685 d"" / f',
(708-47)
and
The grout strength shall not exceed 35 MPa for the purposes of Formula (7 08-46) and (708-47).
Joint shear forces shall be calculated on the assumptiollthat the stress in all flex ural tension reinforcement of the beams at that pier faces is J.4 f~.. Strength or joint shall be governed by the appropriate strength reduction factors specified in Secti on 708.1.4.4.
Deam longitudinal reinforce ment terminating in a pier shall be extended to the far face of the pier and anchored by a s tandard 90 or 180 degree hook, as defin ed in Section 708.2.2.4, bent back to the beam.
th
National Stru ctura l Code of the Pililippi nes 6 Edition Volum e 1
/ ·:38
CHi\PTEH 7 Masonry
709.2.1.3 Dcsign Strcngth
709.1 Scope The seismic design requirements of this section apply to the design of masonry and the construction of masonry building clements, except glass unit masonry, for all seismic
The design strength of masonry provided by a mcmber, its conncctions to othcr mcmbers and its cross sections in terms of flexure, axial load, and shear shall be taken ilS the. nominal strength multiplied by a strength reduction factor,
o
(a) Axial load and flcxure (.;.':cept for llexural
performance categories as defined in ASCE 7.
tension in unreinf0rced masonry (b) Flexural tension in unreinforced masonry
709.2 General Masonry structures and masonry elements shall comply
(e) Shear (d) Shear and tension in anchor bolts embedded
with the requirements of Sections 709,3 through 709.7 based on Seismic Performance Categories A, B, C, D or E as defined on ASCE 7. In addition, masonry structures and
masonry clements shall comply with either the requirements of Section 706 or the requirerncnls of Section 709.2.1
709.2.1 Strength Requirement For masonry struclures that are nol designed in accordance with Section 706, the provisions of this section shall apply. The design strength of masonry structures and masonry elements shall be at least equal to the required strength determined in accordance with this section, except for masonry structures and masonry elements in Seismic Performance Category A designed in accordance with the provisions of Section 7 J O. 709.2.1.1 Required Strength RequiI:ed strength, U, to resist the seismic forces in such combinations with gravity and other loads, including load factors, shall be as required in the em1hquake loads section of ASCE 7, except that nonbearing masonry walls shall be designed for the seismic force applied perpendicuhu' to the plane of the wall and uniformly distributed over the wall area in lieu of the provisions of ASCE 7 Section 9.8. L L 709.2.1.2 Nominal Strength The nominal strength of masonry shall be taken as 2.5 times the allowable stress value. The allowable stress values shaH be determincd in accordance with Section 707.2 or Section 707.3 and arc permitted to be increased by one-third (1/3) for load combinations including earthquake.
in masonry
0= 0.80 0=O.4() 0=0.60 0=0.60
709.2.1.4 Drift Limits The calculated storey drift of masonry structures due to the combination of seismic forces and gravity loads shall nut cxceed o.cxn times the storey hcight. 709.3 Seismic Performance Category A Structures in Seismic Performance Category A shall comply with the requirements of Sections 707, 708 alld 710.
709.3.1 Anchorage of Masonr), Walls Masonry walls shall be anchored to the roof and aU floors that provide lateral support for the wall. The anchorage shall provide a direct connection between the walls and the floor or roof construction. The connections shall be capable of resisting the greater of a seismic lateral force induced by the wall or 14590 times the effective pcak velocity- related acceleration, N/m of wall. 709.4 Seismic. Performance Category B Structures in Seisrnic Performancc Category B shall comply with the requirements of Seismic Performance Category A and to the additional requirements of this section. The lateral force resisting system shall be designed to comply with the requirements of Sections 707 and 708. 709.5 Seismic Performance Category C Structures in Seismic Performance Category C shaH comp).· with the requirements of Seismic Perf"onnancc Category B and to the additional requirements of this section.
Association of Structural Engineers of the Philippines
CHAPTEH'1 . Masonry
709.5.1 Dcsign of Elements that are Not Part of Latcral F()rce~nesisting System 709.5.1.1 Load Bearing Frames Load bearing frames or columns that are not part of the latera! force resisting system shall be analyzed as to their effect on the response of the system. Such frames or columns shall be adequate for vertical load carrying capacity and induced moment duel to 'the design story drift.
709.5.1.2 Masonry Walls and Elements Masonry p;:uiition walls, masonry screen walls and other masonry elements that are not designed to resist vertical or lateral loads, other than those induced by their own mass, shall be isolated from the structure so that vertical and lateral forces are not imparted to these elements. Isolation joints and connectors between these elements and the structure shall be designed to accollllllodate the design story drift.
709.5.1.3 Reinfol"{'cment Requirements for Masonry Elements
Masonry elements listed in Section 709.5. 1.2 shall be reinforced in either the horizontal or vertical direction in accordance with the following: 709.5.1.3.1 Horizontal Reinforcement Horizontal joint reinforcement shall consist of at least two longitudinal WI.7 wires spaced not more than 400 mill for walls greater than 100 mill in width and at least one longitudinal WI.7 wire spaced not more 400 mm for walls not exceeding 100 111m in width; or at least one 12 111111 diameter bar spaced not more than 1.2 Jl1. Where two longitudinal wires of joint reinforcement are used, the space between these wires shall be the widest that the 1110liar joint will accommodate. Horizontal reinforcement shall be provided within 400mm of the top and bottom of these masonry elements. 709.5.1.3.2 Vertical Reinforcemen't Vertical rei nforcement shall consist of at least one 12 mm diameter bar spaced not more than 1.2 Ill. Vertical reinforcement shall be located within 400 mm of the ends of masonry walls. 709.5.2 Design of Elements titat are Part of the Force - Resisting System
L~ttenll
709.5.2.1 Connections to Masonry Shear Walls Connectors shall be provided to transfer forces between masonry walls and horizontal elements in accordance with the requirements of Section 706. Connectors shall be designed to transfer horizontal design forces acting either
/-3q
perpendicular or parallel to the wall, but not less than 2.9 kN/m of wall. The maximum spacing between connectors shall be 1.2
111.
709.5.2.2 Connections to Masonry Columns Connectors shall be provided to transfer forces between masonry columns and horizontal clemcnts in accordance with thc requirements of Section 706. Where anchor bolts are llsed to connect horizontal clements to the tops of columns, anchor bollS shall be placed within lateral ties. Lateral tics shall enclose both the vertical bars in the column and the anchor bolts. There shall be a minimum of two 12 mm diameter lateral tics provided in the top 125 mm of the column. . 709.5.2.3 Minimum Reinforcement Requirements for Masonry Shear Walls Vertical reinforcement of at least 129 mm 2 in crosssectional area shall be provided at comers, within 400 mill of each side of openings, within 200 mm of each side of movement joints, within 200 mm of the ends of walls, and at a maximum spacing of 3.0111. Horizontal joint reinforcement shal! consist of at least two WI.7 wires spaced not more than 400 mm; or bond beam reinforcement shall be pr~:)Vided of at least 129 mm 2 in cross-sectional area spaced not more than 3.0 m. Horizontal reinforcement shall aiso be provided at the bottom and top of wall openings and shall extend not less than 600 mm nor Jess than 40 bar diameters past the opening; continuously at structurally connected roof and floor levels; and within 400 mill of thy top of walls. 709.6 Seismic Performance Category D Structures in Seismic Performance Category D shall comply with the requirements of Seismic Performance Category C and to the additional requirements of this section. 709.6.1 Design Requirements Masonry clements other than those covered by Section 709.5. 1.2 sh,1I1 be designed in accordance with the requirements of Sections 707.2 and 708.2. 709.6.2 Minimum Reinforcement Requirements for Masonry 'Valls Masonry walls other than those covered by Section 709.5.1.3 shall be reinforced in both the vertical and horizontal direction. The slim of the cross-sectional area of horizontal and vertical reinforcement shaH be at least 0.002 times the gross cross-sectional area of the wall, and the minimum cross-sectional area in each direction shall be not less than 0.0007 times the gross cross-sectional area of the wall. Reinforcement shall be uniformly distributed. The
th
National Structural Code of the Philippines 6 Edition Volurne 1
7·-10
C HAPH:l-11
IV1.:1S01lf}1
I1l<1XimUIll spacing o f rc infon.:cmcilt sha ll hc 1.2 III provided th at the w;lIls lIrc solid grouted and cons tructed of hollo w opcrH~Jld units, hollo w units laid wi th full head joints or two wythcs of so lid units. The ma xi mum slMc in g or rcinfon;c rll CIl I shall be 600 Illlll for all other masonry.
SECTION 710 EMPIRICAL DESIGN OF MASONRY 710.1 Height Building relying Oil IlWS(}OI"Y will!s for late ral resistance shall not exceed !() III inllcigill.
IO'ld
709.6.2.1 Shear '''all Reinforcement Requiremen ts The maximum spacing of vertical and horizo ntal reinforccment shall pc the Sllh'.llcr or; onc·third th e k~ngth of th e shear wall, 911c-third the height of th e shear wull, 1.2 Ill . . The minimuill cross-sectional area of vertical reinforcement shall be one-third of the requi red shear reinforcement. She;:lr reinforcement shall be anchored .Iround ve rti cal reinforcing bars wit h .1 Slalldard hook.
710.2 Lateral Stability Where the slrucill!"e depends 0 11 ll1i1sonry walls for lateral stability, shear walls shall be provided parallel to the direct ion of the lalcral forces r~si s t cd.
709.6.3 MinimullI Reinforcement for Masonry Col ulllils L.ateral li es in mason ry columns shall be 5:p;lced nOI mor'c Ihan 200 mill on cen tcr and shall bc
In each direclion in which shear walls
709.6.4 MHterial Requirements
Neither Type N mortar nor masonry cement shal l be used as pan of th e lateral force resisting system. 709.6.5 Late"al Tie Anchorage Standard hooks for lateral tic anchorage shall be either a 135 degree sta ndard hook or a J SO degree stand
709.7 Seismic Performance Category E Structures ill Seismi c Pelfonnance Category E shall com ply with the req uirements of Seismi c Perform ance Category D and to Ihe addi ti onal requircments of this section. 709.7.1 Design of Elements that Force Resisting System
,\J'C
Not Part of Lateral
Stack bond masonry that is not pan of thc lateral forceres isting sys tem shall have a hori zontal cross secti onal area of reinforcement of at least 0.0015 tim es the gross crosssec ti onal area of masonry. The maximum spacing of hori zo ntal reinforcement shall be 600 mm. These elements shall be solidly grouted and shall be constru c.ed o f hollow open ·end units or two wythes of solid unit s.
709.7.2 Design of Elements that are Pal't of Lateral Force Resisting System St
Minimulll nominal thickn ess he 200 111 11l .
0 11
masonry shea r wall s shall
wall s provided shall be 0.4 times the dimension of the building. The cumulative length oj" she ilI' walls shall not Include openi ng.~. The maximurll spacing o j" shea r WI.! !ls sll a!l flot exceed the ratio listed in Table 710- I . 710.3 Compressive Stresses 710.3.1 General Compressive stresses in masonry due to ve rt ical dcad loaJ." plu s live loads, excluding wi nd or seismit: loads, shall Iv.:' dctennined in accordance with Sct:lion 7 10.4.3. Dead
given in Table 71 0-2 for the weakest combination of the units and mortar used in an y load wythe shall be used for loaded wythes of multi · wythe waH s. 710.3.3 Stress Calculations Stresses shall bc calculated based on specified rather ~ '. nominal dimensions. Calculated compressive slressc:: '. " •." bc de term ined by di vi ding the design load by the gili ....; cross-sectional arc,1 of the member. The arca oj" OpCIl >~' ch
Association of Structura l Eng ineers of the Philippines
710.4 Lalcral Supp!u'l Masonry walls sh Oll! be laterally supporlcd in eit her the' horizoJltal or vertical direction no! exceeding (h e int erv al s se t forth in T
for parapet' \;Valls. the rati o of height
10
nominal
thi ckness for cantilever Willis shall not exceed 6 for so lid masonry or 4 for hollow masonry.
In computing the I'<\lio for cavily walls, the value of thickness shall be the SUIllS of the nominal thickn ess of the inner and outer wythes of the masonry. III walls co mposed of different classes of units and monars, the ratio of height or length to thickness shall /lol exceed that allowed fo r the weakes t o r the combinations of unit s and monar of which th e member is composed.
710.5 Minimum Thickness 710.5.1 General Th e nominal thickness of masonry bearing walls in buildings more than one story in height shall not be less than 200 111m. Solid masonry walls in one-storey buildings may be of 150 111m nominal thi ckness when not over 2.7 m in height , provided that when gable construction is used, an additional 1.8 111 is permitted to the peak of the gable. Exception: Th e thickness of unrein/arced grouted brick masonry walls may be 50mm less than required by flii.'i section, bur i/l no case less (han 150 111m.
710.5.2 Varialion in Thickness Where a change in thickness due to minimum thickn ess occurs between fl oor level s, th e greater thickness shall be carried up to the higher floor level. 710.5.3 Decrease in Thickness Wh ere walls of masonry of hollow units or rnasonr ybonded hollow walls are decrease in thi ck ness. a cours e or courses of solid masonry shall be const ructed bet ween the walls below and the thinner wall above, or special units or construction shall be used to transmit th e loads from face !> hells or wythes to the walls below.
710.5.4 I'arapels
Parapet walls shall be at least 200 mill in thickness and their height -shall not exceed three times their thickness . The parapet wall shall not be thinner than the wall below.
710.5.5 FOllndatioll Walls Morl
eitht~r
Type M or S.
Where the height of unb.liilllccti fiJI (ht~ight of flilishl.'d grad e above basemcnt /loor or in side gradc) and the hei gh! of the wall between lateral support docs not cxcced 2.4 Ill, and when the equivalent Iluid weight 01' un balanced Iill docs not exceed 480 kg/m 2, the. minimum thickncss of foundation walls shall bc as set forth in 'rable 710~5. Maximum depths of un balanced fill pcnniltcd in Table 7105 Illay be increased with the approval of the building official when local soil condi tion s warrant such an increase. Where the hcight of unbalanced fill, heigh t betwecil lateral supports or equivalent fluid weight of unbalanced fill exceeds that set forth above, foundation walls shall bc designed in accordance with Chapter 3. 710.6 Bond 710.6.1 General The facing and backing of multi-wythe masonry walls shall be bonded in accordance with this section. 710.6.2 Masonry Headers Where the facing an d backing of solid masonry conslnlction are bonded by masonry headers, not less than 4 percent of the wall surface of each face slHllI be composed of headers extending not less than 75 mm into thc backing. The distance between adjacent full ~ le ngth headers shall not exceed 600 mill either vertica!ly or horizontally. In walls in ..>,.'hieb a $ingle header does not extend th rough the wHII, headers from opposite sides shall overlap at least 75 mm, or headers from opposite sides shall be covered with another header course overlapping the header below at least 75 mill .
Where two or more hollow unit s are used 10 make up {he thickness of the wall, the stretcher courses shall be bonded at vertical intervals not exceeding 865 mm by lapping at least 75 mOl over the unit below, or by lapping at verti cal intervals not exceeding 430 mm with units which are at least 50 pe rcent greater in thi ckness than the units below. 710.6.3 Wall Tics Where th e facing and backin g of masonry wall s are bonded with 4.8 mill diameter wal! ties or metal tics of e-qllivi.i1cnl stiffness embedded in the horizontal mOJ1ar joi nts, th ere shall be ell least one metal tie for each 0.42 m2 or wall area. Ties in allematc courses shall be staggered, tile maximum vertical distance between tics shall not exceed 600 mm, and the maximum horizontal distance shall not exceed 900 mill. Rods ben I to rectangular shape shall be used with hollowmaso nry units laid with the cells vertical. III olher walls, the ends of ties shall be bent to 90-degree angl es to provide th
National Structural Code of the Philippines 6 Edition Volu me 1
hooks not less thall 50 mm long. Additiollal ties shall hc prov ided a l 1.111 open ings, Spilccd !lot more (han 900 mill apart aro und th e perimeter and. within 300 mm of the opening. The facing and b;!(' king of masonry Wil li s may be bonded with prcfabri('ated joi nt reinforce ment. There sh
t
I, I
710.6.4 LOllgitudilllllllolld In each wythe of masonry, head joints in successive co urses shall be ofL.;;et at least one fourth of the unit length or the wall s shall be reinforced longi tudinall y as required in Seclioll 706. 1.1 2.3, IIem 4.
710.7 Allchorllgc 7]0.7.1 In(crsccting " '
2.
Fifty percen t of (he units at the intersection shall be laid in an overlapping pattern, with alternating units havin g a bearing of not less than 75 I11Ill on the unit below. Walls shall be anchored hy steel connectors having a minimum section of 6 mm by 38 mOl with ends bent up at least 50 111m, dr with cross pins to form anchorage. Such anchors shall be al leas t 600 mm long and th e maximum spacing shall be 1.2 rn verticall y.
I.
Wood fl oor joists ht'|
2.
Steel floor joists shall be anchorcd to masonry wall ,; with 10 mill diamclCr bars, or their equ iv,lIcllt, "'p,l(X '; not more than I.H m on celller. Where joist.'> :; '-,: parallel to the wall , ancho rs shall be located at joi sts cross bridging.
J.
Roof struclUrcs shall be tIllchored 10 1ll,Isollry w;-i' -; with 12 I11Ill bolts at 1.8 III on center or their equivalent. Bolts shall extend and be embedded at !cast 400 !')'! into th e masonry. or be hooked or welded to Ij( l( i than 130 mm l of bond he
710,7.3 Walls Adjoining Structural Framing Wherc wa lls arc dependcn t 011 the structu ra l ffa tne \"(;;. latera l support, th ey shall be anchored to the s t rUt l" members with metal anchors or keyed to th e Sln l' members. Metal anch ors shall consist of 12 mill hl)u ~~ sp
Maso nry of stabilized cl ay unburned units shall not be u~;ed in any building more than one story in height. The unsupported heigh t of every wa ll or unhunlcd clay units shall not be more than 10 times the th ic kJless nfstleh w;: lls. Bearing walls shall in no case be less than 400 n'r;1 th ickness. All footin g walls whi ch support maSOlJ' unburned cl ay un its shall ex tend to an elevation nul [;.;:..:; tlHlIl J 50 mm above the adjacent ground at all points.
3.
Walls shall be anchored by j oint reinforce ment spaced at a maximum distance of 200 mm verticall y. Longitudinal rods of such reinforcement shall be at least No.9 gage and shall extend at least 750 111m in each direction at the intersection.
4.
Int e ri o r no nbea ring wall s may be anc ho red at thei r
Bolt va lues sl1(l1l not exceed those set forth in Table 710/ .
intersection, at veJ1ica l spaci ng of not more than 400 mill with joint reinforcement or 6 mill mesh galvan ized hard ware cloth.
710.9 Stonc Masonry
Ot her metal lies, joint reinforce men t or anchors Illily he used, provided they arc spaccd to provide cquivnJellt arca of anchorage to that required by th is section.
SlOne masonry is thaI form {)f co nst ruction made with
5.
710.8,2 Bolt,
710.9.1 Genel'lll
natura! or cast stOlle in which the units arc laid (mel mOl1ar with all joints filled.
~, :(
)11
710.7.2 Floor alld Roof Anchorage Floor and roof diaphragms providing lateral support to masonry walls shall be connected to the masonry walls by one of the followin g methods:
710.9.2 Construction In ashlar maso nry, bond stones uniformly dislriill,t\ ,.:d ,\" '1 be provided to the extent of not less than 10 jKTC t'; ,i -,(.' arca of exposed facets. Ru bble stolle masonry GUO mill or less in thickn css shall have bond stones with a maximum
Association of Structural Engineers of the Philippines
spar.:ing 01'900 mill vertically and 900 Hlin horizonHil!y and, jf tile masonry is of" greater thickness than 600 mm, shall 2
have one bond stone for each 0.56 m of wHII surface on both sides .
SEC'f;IDl'iJ.71l
GLASS.MASQNRY 711.1 General
710.9.3 Minimum Thickness
The thickness of slOne masonry bearing walls shall not be less than 400 mm.
..
Masonry of glass blocks Illay be used ill /lon-loud-bearing cXlerior or interior walls ,lllti in openings wh ich might ot herwi se be filled with windows, cither is oluted or in cont inuous bands, provided the glass block panels h,lve a miniI.11UJ11 thickness of 75 mm at the mortar joint and the mortared surfaces of the blocks arc treated for mortllr bonding. Glass block may be solid or hollow and may contain inserts. 711.2 Mortar Joints
Glass block shall be laid in Type S or ~ mortar. Both vertical and horizontal mortar joints shall be at least 6 mm and not more than 10 mill thick and shall be completcly filled . All monar cOnlac{ surfaces shall be treated to ensure adhesion between mortar and glass. 711.3 Lateral Support
Glass panels shall be hlterally supported along each end of the pancl. Lateral support shall be provided by panel anchors spaced not more than 400 mm on center or by channels. The lateral support shall be capable of resisting lhe horizo ntal design forces determined in Chapter 2 or a minimum of 3 kN/rn of wall, whichever is greater. The connection shall accommodate movement requirements of Section 711.6. 711.4 Reinforcement
Glass block panels shall have joint rei nforcement spaced nOl more than 400 111m on ccnter and located in the 11)011ar bed joint extending the entire length of the panel. A lapping of longitudinal wires for a minimum of 1SO mm is required for joint reinforcemen t splices. Joint re inforcement shall also be placed in the bed joint immediately below and above openings in the panel. Joint reinforcement shall conform to ASTM A 385 and A 641.
Joint reinforcement in exterior panels shaH be hOI-dip gal vani zed in accorda nce with ASTM A 385 and A 641 . 711.5 Size of Panels
Glass block panels for exterior wal ls shall not exceed 13.5 111 2 of unsupport.ed wall surface or 4.50 III in any dimension. For interior walls, glass bloc k panels shal l not exceed 23.2 11)2 of unsuppol1ed area or 7.60 In ill any dimension.
National Structural Code of the Philippines 6'" Edilion Volume 1
711.6 Expansion Joints Glass block shall be provided with cxpansion joints along the .';idcs and top, and these joillls shall have surlicicnt thickness [() accommodate displacemcnts of th e supporting SllUclUrc, but /lot less than 10 mill . Expansion joints sJull1 be entirely free of mortar and shall be filled with resilient material . 711.7 Reuse of Units Glass block units shall !Hlt be reused after being removed frolll an existing panel.
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SECf1!J@N .712 ... . . MASONRY FIREPLACES 7 I 2. I Definition A masonry fireplace is a fireplace constructed of COllcret(~ or masonry. Masonry fireplaces shall be constl11C1cd i ;: accordance with this section. 712.2 Footings and Foundations Footings for masonry fireplaces and their chimneys shall be cOllstnlcted of concrete Or solid JIlasonry al least 300 lllm thick and shall extend at least 150 mill beyond the face of the firepLace or foundation wall on :i11 sides. Footings shall be founded on natural undisturbed earrh or engineered fill below frost depth. In areas not SUbjected to freezing, foolings shall be at least 300 nun below finished grade. 712.2.1 Ash Dump C1eanout Cleanout openings, located within foundation walls below fireboxes, when provided, shall be equipped with ferrous metal or masonry doors and frames COllstlll(;ted to remain tightly dosed, except when in usc. Cleallouts shall be accessible and located so that ash removal will Ilot create a hazard to combustible malerials . 712.3 Seismic Reinforcing Masonry or concrele fireplaces shall be constructed, anchored, su pported and reinforced (is required in thi s chapter. In Seismic Design Category D, Illasonry and concre te fireplaces shall be reinforced and anchored as detailed in Section s 7 I 2.3. J, 7 I 2.3.2, 7 I 2.4 and 71 2.4. I for chimneys servi ng fireplaces. In Seismic Design Category A, B or C, reinforcement and seismic anchorage is not req uired. In Seismic Design Category E or F, masonry and concrete chimneys shall be reinforced in accordance WiUl the requirements of Sections 701 through 709. 712.3.1 Vertical Reinforcing
For fireplaces with chimneys up to 1.0111 wide, four 10 mm diam ete r continu ous vertical bars, anchored in the foundation, shall be placed in the concrete between wythes of solid maso nry or within the cells of hollow lInit masonry and grouted in accordance with Section 703.4. For fireplaces with chim neys greater than 1.0 III wide, two additional 12 mill diameter vertical bars shall be provided for cnch additional J.O III ill wid th or frac tio!) thereoL 712.3.2 Horizontal Reinforcing Ve!1ical reinforcement shall be placed enclosed within 6 mill) tics or other reinforcing of equivalent net cro~ · sectional area, spaced not to exceed 4S0 mm on center in
concrete; or placed in the bed joints of unit masonry at a
Association of Structural Engineers of the Philippines
CHAPTFH l . 1,,1asonry
minimum of every 450 nun of vertical height. Two such ties shaH be pro vided at CilCh bend in the vertical bars.
712.4 Scismic Anchorage Masonry and concrete chimneys in Seismic Design Category. D shall be anchored at each 11001', ceiling or roof lille marc than 1.8 III above grade, except where const ructed compl etel y within the exterior walls. Anchorage shall confonn to the fo llowing requiremen ts. 712.4.1 Anchorage 4.8 mm by 25 mm straps sha ll be embedded a minimum of 300 mm into th e chimney. Straps shall be hooked around the outer bars and extend ISO mm beyond th e bend . Each strap shall be fastened to a minimum of four Ooor joists with two 12 mm bolts.
712.5 Firebox Walls
, ·45
712.7 Lintel and Throat Maso nry ove r a fireplace opening sh all be su pported by il lintel of noncombustibl e material. The minim um requ ired bearing length on each cnd of the fireplace opcn ing shall be 100 mill. The fireplace throat or damper sh:.tll be hx:a tcd a minimum of 200 mill above th e top of the IircpJacc ope ning. 712.7.1 Damper Masonry fireplaces shall be equi pped with CI fcrro\l"~": "l1letal damper located at least 200 mill above the top of the fireplace open ing. Dampers sha ll be installed in the fireplace or at the top of the Ouc ventin g the fireplace, and shall be operable from the room containing the fireplace. Damper controls shall be permitted to be located in the firepl ace. 7 12.8 Smoke Chamber Walls
Masonry fi reboxes shall be constru cted of solid masonry ullits, ho llow maso nry units grout ed so lid, stone or co ncrete. When a lining of firebri ck at least 50 mm in thickness or ot her approved lining is provi ded, the minimum thickn ess of back and sidewalls shall eac h be 200 mm of soli d ma sonry, includin g the lining. The width of joints between firebricks shall not be greater than 6 mm. When no lining is provided, the to tal minimum thickness of bac k and sidewall s shall be 250 mill of solid masonry. Firebrick shall conform to ASTM C 27 or ASTM C 1261 and shall be laid wit h medium-duty refractory mortar confonning to ASTM C 199.
712.5.1 Steel Fireplace Unit, Steel fireplace units are permitted to be installed with solid masonry to form a masonry fireplace prov ided they are installed acco rding to ei ther the req uirements of their listing or the requirements of thi s sect ion. Steel firepl ace un its incorporating a steel firebox linin g sh all be co nstructed with steel not less than 6 mm in thi ckness, and an air-c irculating chamber which is duet ed to the interi or of the buildin g. The firebox lining shall be encased wi th solid masonry to pro vide a total thickn ess at the back and si des of not less than 200 mm , of which fl ol less than 100 mill shall be of solid masonry or con crete. C ircul ating air duc ts employed wi th stee l fireplace units shall be constructed of metal or masonry. 712.6 Firebox Dimensions Th e firebox o f a concret e or ma so nry firepl ace sha ll have a mini mu m depth of 500 mm . Th e throm shall not be less thHI1 200 mm above the fireplace o penin g. Th e throat opening shall not be less than 100 mm in depth. The cross· sec tional area of the p assageway above the firebox, in cludi ng th e throat, damper and s moke chamber, shall not be less than the cross-sectional area of the flu e.
Smoke chamber walls shnll be constructed of solid masonry unit s, hollow masonry units grou ted solid, stone or concrete. Corbe ling of masonry units shall not leave unit Cores exposed to th e inside of the smoke chamber. The inside su rface of corbe led masonry shall be parged smoolh. Where no lining is provided, the total minimum th ic kness of frolll, back and sidewall s shall be 200 mm of solid masonry. When a lining of fire bri"ck at least 50 mill thick, or a linin g of vitrified clay at least 16 mm thi ck, is provided, the total minimum thickness of front, back and sidewa ll s shall be 150 mm of solid masonry, including Ih e linin g. Firebrick shall conform to ASTM C 27 or ASTM C 1261 and shall be lai d wi th refracto ry mortar conformi ng to ASTM C 199. 712.8.1 Smoke Chmnber Dimensions The inside hei gh t of the sm oke chamber from the fireplace throat to the beginning of the flue shall not be greater th an the inside width of the firep lace opening. The inside surface of the smoke chamber shall not be inclined more than 45 degrees (0.76 rad) from vertical when prefabricated smoke chamber linings are us ed or when th e smoke chamberwall s are rolled or sloped rather than corbeled. When the inside su rface of the smoke cha mber is formed by corbeled masonry, the wa ll s shall not be corbeled more than 30 degrees (0.52 rad) from venica!.
712.9 Hearth mId Hearth Extension Masonry firep lace hcat1.hs and hea rth c-xtc..:lSions shall be const lucted of concrete or masonry , sup po l1 ed by noncombu st ible materials, and reinforced to carry their own weight and all im posed loads. No combust ible materi al shall rem ain against the underside of hearth s or hearth ex ten sions aft er constructi on.
National Structural Code of tile Philippines 6'" Edition Volume 1
712.9.1 Hearth Thicklless T he minimulll
!hickn l~ss
4.
of fircplm:c hc,lI1h s shall he 100
mill ,
712.9.2 Ht.'arth Extension Thickness Th e minimulll thic knes s or hearth ex te nsi o ns shall be 50 Jlllll .
1;,~rCeIJl ;()1I :
Wh en th e b O/fOIll of the firebox o/)£!nillg is raised at Ifast 0.20111 above the fOp of rhe heart" eXfell sifJII, (I !warlh extension of not less than 10 mm thick brick, concrele, ,\'(OJle. [i if! o r other approved IIollcomJm.Hibh! 1II00erial is
Exposed combustible malltels o r trim is permitted to be placed directly 0 11 the nlasolllY fireplaa from surrounding the fireplace opening provided sl/ch combustible malerials shall 1101 be placed within 150 111m of a fi replace opening, Combustible material directly above alld with ill 300 mm of tlU! fireplace opening shall fwt project more fhan 3,2 mm for each 25 mm distance from such opening. Combustible materials located along the sides of the fireplac e opening ihat project more than 40 mmfrom th e/ace of the fireplace shall have all additional clearance equal to th e projection.
permilfal.
712.10 H ea rth Extension Dimensions Hearth extens ions shall ex te nd a l leas t 400 mill in fro nl of, and at leas t 200 I11Ill beyond, each side or the lircplacc opening. Where the firepl ace openin g is 0.60 111 1 or larger.
the hearth extension shall exte nd
~I\
least 500 mm in front
o f. a nd aI least 3
712.11 Fireplace Clearance Any pOl1i on of a masolll)' fireplace loc-:IIcd in the interi or of a building or within the exte rior wall o f a building sh all ha ve a cl earance to combusti bles o f not less (han 50 Illlll from the front fa ces and sid es of masonry fireplaces an d not Jess than a . lOm frolll the back faces of maso nry fi replaces. The airspace shall not be fill ed , except to- provide firebloc kin g in accordance w ith Sec ti on 7 J 2. 12.
Excep tio."s: I,
Mason ry fireplaces listed Qnd labeled fo r use ill cOflfact' with combustibles in Qccordance wi,II UL 127 and illstalled iTl accordance with the manufacturer 's installation instructiolls are permitted to have combustible materia l in contact with their exterior suifaces.
2.
When masonry fireplaces are cOllstructed as part of .masonry or Concrete walls, combustible materials shall 110 1 be ill contact wilh Ihe masonry or COf1C,.el l~ walls less thall 300 mm fro m th e inside surface of th e f/£~ares{ firebox hn ing .
3.
J
Illustrati on of Excepti on to Fireplace Clearance Provision
Exposed combustible trim and the edges of sh eathing materials. stich as wood siding, flooring and dl)ll1loll, are pe rm itted to abut th e masonry {lrepltlce side walls alld hearth extellsion. ill accordance with Figure 712 .11, provided such combustible trim or sh eathing is a minimum of 300 mm from Ihe inside Sill/ace of the nea rest firebox linillg.
712.12 Fireplace Fireblocking A ll spaces between fire pl aces and floors and ce ilin gs
throu gh which fireplaces pass sh a!! be fireblocked with noncombustible materi al sec ure ly faste ned in pl ace. Th e fi rebl oc king of spaces between wood joists, be ams or headers s hall be to a depth of 25 mm and shall on ly be pJaced on strips of metal or metal lath laid across the spaces be tween combustible material and the chimney,
712.13 Exterior Air Fact ory-built or ma sonry firepl aces covered in this section shall be eq uipped wit h an ex terior air su ppl y to ensure proper fuel combustion unless the room is mechan icall y ventilated and con troll ed so that the indoor pressure is neutral or pos itive. 7 [2.13.1 FactOl·y·lluilt Firephlccs Ex te ri or combustion air due ls for faclOry-built fireplaces shall be li sted compone nts of th e fi repl ace., a nd in stalled 'lccord ing to the fi replace manufacture-.r' s instruc ti ons ,
712.13.2 Masonry Fireplaces Listed combustion ,a ir ducts for masonry firepl aces shall h~ installed accord ing (0 the lcnns of the ir listing ~\lid manufacturer's in structions,
Associa tion of Structural Engineers of th e Philippines
CHAPTEFll .
712.13.3 Exterior Air Intake The exterior air intllke shall be capable of providing all combustion air from the exterior of the dwelling. The exterior air intake sha!! not be located within the garage, allie, basement or crawl space of the dwelling nor shall the air intake be located at an elevation higher than the firebox. The exterior air intake shall be covered with a corrosionresistant screen of 6.4 mm mcsh. 712.13.4 Clearance
~~asonry
7·-17
713.1 Delinition A masonry chimney is a chimney constructed of concrete or masonry, hereinafter referred 10 as "masonry." Masonry chimneys shall be constructed, anchored, supported and reinforced as required in this chapter.
Unlistcd combustion air ducts shall be installed with a minimum 25 Il1m clearance to combustibles for all parts of
the duct within 1.5
III
of the duci outlet.
712.13.5 Passageway
The combustion air passageway shall be a minimum of 1112, except thai combustion air systems for listed fireplaces or for fireplaces tested for emissions shall be constructed according to the fireplace manufacturer's instructions. 0.040 m 2 and not more than 0.035
713.2 Footings and Foundations Foo\ings for masonry chimneys shall be constructed of concrete or solid masonry at least 300 mm thick and shall extend at least 150 mm beyond the face of the foundation or support wall on all sides. Footings shall be founded on natural undisturbed eanh or engineered fill below frost depth. In areas not subjected to freezing, footings shall be at least 300 111m below finished grade. 713.3 Seismic Reinforcing
713.13.6 Outlet
The exterior air outlet is permitted to be located in the back or sides of the firebox chamber or within 600 mm of the firebox opening on or near the floor. The outlet shall be closable and designed to prevent burning material from dropping into concealed combustible spaces. ·.\<'·Wtx~ '~i.'··:·;>::S;i~F":
.
-
Masonry or concrete chimneys sha!l be constructed, anchored, supported and reinforced as required in this chapter. In Seismic Design Category D, masonry and concrete chimneys shall be reinforced and anchored as detailed in Sections 713.3.1, 713.3.2 and 713.4. In Seismic Design Category A, Bore, reinforcement and seismic anchorage is not required. In Seismic Design Category Eor F, masonry and conCrete chimneys shall be reinforced in accordaQce with the requirements of Sections 701 through 709.
713.3.1 Vertical Reinforcing
For chin;neys up to J.O m wide, four 12mm diameter continuous vertical bars anchored in the foundation shall be placed in the concrete between wythes of solid masonry or within the cells of hollow unit masonry and grouted in accordance with Section 703.4. Grout shall be prevented from bonding with the flue liner so that the flue liner is free to move with thermal expansion. For chimneys greater than 1.0 m wide, two additional 12 mm vertical bars shall be provided for each additional 1.0 III in width or fraction thereof. 713.3.2 Horizontal Reinforcing VeJ1icai reinforcement shall be placed enclosed within 6.4 mrn tics, or other reinforcing of equivalent net crosssectional area, spaced not to exceed 450 mm o.c. in concrete, or placed in the bed joints of unit masonry, at a minimum of every 450 mm of vertical height. Two sLlch ties shall be provided at each bend in the vertical bars.
th
National Structural Code of tile Philippines 6 Edition Volume 1
/·,18
CHAPTEH 7 . Masonry
7 13.4 Scislllk Ant..'horagc
Maso nry and concrete chimneys and fo und ations in Seismic Design Category D sha ll t)C anchored at each f1 oor. ceiling or roof lille more th an 1.8 III above grade, exce pt where constructed compl ctely wi thin the exlerior wall s. Anchorage shall co nfo rm to lilc fol lowing rcq u i reme nl ~.
713.9 Termination Chimneys shall extend at leas t 600 I11Ill hi ghcr than allY porti oll of Ihe buildi ng wil hin 3.0 Ill, but shall not be less th an 900 m ill above the hi ghest poin t where Ihe chi mney passes through the roo f. 713.9.1 Spark Arrestors
713.4. 1 Anch orage
Two 4.8 mill by 25 mill straps shall bc embedded a mi:li mum of 300 nun into the chimney. Straps shall be hoo ked arollnd the outer b.w.; and extend 150 mill beyond the bend. Each strap shall be fas tened to a mini mu m of fo ur floor joists with two 12 mill bolts. 713.5 Corbeling Masonry chi mneys shall Ilul be corbelled more th an half of the chim ney 's wall thickness from a w.l ll or fou ndation, nor shall a chimncy be corbeled from a wall or foundati on that is less than 300 mill in Ihickness un less it prl.~ec t s equ all y on each side of Ihe wa ll , exce pt that on thc second story of a two -slO ry dwelling, co rbelin g of chimneys on the exterior of thc encl osing wal ls is pennillcd to equal the wall thickness . The projection of a singl e co urse shall not exceed one~h a lf the unit hei ght or o n c~ third of the unit bed de pth , whichever is less.
Where a spark arrestor is installed on a masonry chimney. the spark arrestor shall meet all c !' the follOWing requirements: I. The nCI free arca o f the arreSlOr shall not be less tha n fo ur tim es the net free area of tile outl et of the chimney flue it serves. 2. The arrcs tor sc ree n shall ha ve heat and co rrosion res istance equi valc nt to 1 9~ 9a ge galvani zed steel or 24 ~ gage slaill lcss slee l.
3.
Openings shall not permit th e passage of spheres havi ng H di ameter greater th2n J2 mill nor block the passage of spheres ha ving a diameter less than 10 mm.
4.
The spark arrcs tor shall be accessible for cleaning and th e s<.: ree n or chimney cap shal l be rem ovable to allo w fo r clca ning of the chimney fl ue.
713.10 Wall Thickness 713.6 Changes in Dimension
The chi mney wa ll or c himney flue li ning shaH not cha ngc in size or shape within 150 mOl abo ve or below where the chi mney passes through noor co mponenls, ceiling com ponents or roof com ponen ts.
Maso nry chimney walls shall be constru cted of concrete, solid maso nry uni ts or hollow masonry un its grouted solid with not less than 100 mm nominal thickness. 713.10.1 Masonry Veneer Chimneys Where masonry is Llsed as veneer for a fra med chi mney, th rough n ashing and wee p holes shall be provided as required by Chapter 14 of me.
713.70ITsets Where a masonry chim ney is construc ted with a fi reclay flue liner surrounded by one wythe of maso nry. th e rnax imum offset shall be such that the centerlin e of the flue above the offset docs not extend beyo nd the center of the chimney wall below the offset. Where thc chim ney offset is supported by maso nry below the offset ill an approved manner. the maximum offset limitations shall not apply. Each indi vidual corbeled masonry course of the offset shall not exceed th e projection limitati ons specified i~ Section 7 13.5.
713.11.1 Residential·Type Appliances (General) Flue lining systems shall co mpl y with one of the followi ng:
713.8 Additional Load
I.
Clay flu c lining complying wit h the requircm cnts of ASTM 0 15 , or equivalent.
2.
Lis ted chimney lining sys tems com plyi ng wi th UI . 1777.
3.
Faclory*built chimneys or chimney uni ts li sted fe:' installat ion withi n masonry chimneys.
4.
Ot her approvcd materi als that will resist corrosion , erosion. softening or cracking from Oue gases an d condensate at tem peratures up to 1,800' 1' (982' C).
Chim neys shall not support loads other than their ow n weight unless th ey are designed an d constru ct ed to support the additional load. M<\sonry chimneys arc permitted to be constructed as part of the masonry walls or concrete Wil lis of the building.
713.11 Flue Liniug (Material)
Maso nry chimneys shall be lined. The lining material shall be appropriate for the type of appliance connec ted, according to the tenns of the appliance listing and the manpfacturer's inst ructions.
Association 01 Structural Engineers of the Philippines
CHAP TEfll . Mas on ry
'H 9
713.1 J.l.1 Flue Linings for Spedlk Appliances
Fhl(: li nil lgx other than those covered ill Sect!()!l 71 ~.I I.I inte nded for usc with specific applian ces shall com ply with Sect ions 7 13. 1 J. 1.2 through 713. 11.1 .4 and Sections 7 13 . 11.2 ilnd 7 13. 1 1.3. 713.11.1.2 G as Appliallt'es Flue lining systems for gas app liances shall be in acco rdan ce with Ihe T,lumlUfiol1a/ Flit!! Ga.~· ("ode.
713,11.2,) Lining ConcrelC and masonry chiJl1lleys shall be !ined with ,lil approved mediu m-duty refractory brick a min imum of 11 5 mm thi ck lai d o n the 115 Inm bed in an approved mcdiumdut y refractory m o r l(l J". The linin g shall start 6(X) mill or more below the lowe st chi mil ey con nect or elllrance. Chimlleys terminating 7. 5 III or less above a chim ney conneClOr enlnUlce shall be li ned to (he to p. 7 13,11.2,4 Multiple Passageways
713.11.1.3 Pellet Fucl-nurning Appliances Flue lining and venl systems for use in masonry chimneys with pellet fuel-burni.ng appli ances shtlll be limi ted 10 flue lining s y s tem s complying with Secti o n 71 3. 11.1 an d pellet vents listed for in stallati on wi thin maso nry chimn eys (sec Seclion 7 I 3. I I . 1.5 for markin g).
713.11.2.5 Termination Height
713.11.1.4 Oil-Fired Appliances Approved for Usc with L- Vent
Concrete and masonry chimneys for medium-heat applitlllccs shall extend a minimu m of 3.0 m hi gher than any pon ion of allY building within 7.5 m.
Concrete and masonry chimneys containing more than one passage wa y shall ha ve the liners separat ed by a minimum lOO mill thick concrete or solid maso nry wall.
Flu e lining and vc nt syslems for usc in masonry chimneys
with oil-fired appliances appro ved for use with Type L vcnt shall be limited to flu e lining systems co mpl ying with Secti on 713. 11. '" and li sted chimney line rs co mplyin g with UL 641 (sec Seclion 71 3. 11.1.5 for ma rking).
7]3,11.2,6 Clearance
A minimu m clearance of 100 Illlll shall be provided be tween the ex terior surfaces of a concrete or maso nry chimne y for medium-heal appli tlllces and combustible materi al.
713.11.1.5 Notice of Usage When a flu e is relined with a nateri a l not compl y ing w ith Seclion 713. 11.1, Ihe chimn ey shall be plainl y and
permanentl y identifi ed by a la bel attached to a wall , cei li ng or other conspicuous locati on adjacent to where (he connector enters the chimney. The !abel shall include th e following message or cq ui va lenl language: " Thi s chim ney is for use only with (type or category of applian ce) that burns (type of fllcl). Do not connect other types of appliances."
713.11.2 Concrete and Masonry Chimneys for MediumHeat Appliances
.
713,11.3 Concrete and Masonry Chimneys for HighHeat Appliances 713,)1.3,) General
Concrete and masonry chi mneys for hi gh-heat appliances shall compl y wilh Sec ti ons 7 13 .1 Ih rough 7 13 .5. 713.1 1.3,2 Construction
Chimn eys for high ~heat appliances shall be constru cted with double wa ll s of solid masonry units or of concrete, each wall to be a minimum of 200 mrn thick with a minimum airspace of 50 mm between the walls.
713,)1.2,) General
713,11.3,3 Lining
Concrete and masonry chimneys for medium-heat appliances shall comply with Sec tions 713.1 through 713.5 .
The inside of the interior wall shall be lined with an approved high-duty refract ory brick, a minimum 115 mOl th ick laid 011 th e 11 5 mm bed in an approved high-duty re fractor y mortar. The lining shall start at the base of the chimney and ex tend contin uously to the top.
7 ]3,) 1.2,2 Construction Chimllcys for medium -heat appli ances shall bc constructed
of solid maso nry un its or of co ncrete with walls a mi nimu lll o f 200 mm thick, OJ" with ston e masonry a mi nimu lll of 100 mm thick.
7l3.11.3,4 Termination Height
Co ncrete an d masonry chimneys for hi gh-heat appli ances shall ex tend a minimum of 6.0 Jl1 higher th an an y porti on of any building withi n 15.0 IH .
1h
National Structu ral Code of tile Phili ppines 6 Edition Volume 1
7·50
CHAPTEr:1 7 . Masonry
713.11.:1.5 Cle" ..."'"e Concrete and masonry chimncys for high·heClt appli:lf1ces shall havc approved clearance from buildings and structures to prevcnt ove rh eating combustible materials, penn it inspection and maintenance operations on the chimney ilnd prevcnt danger of burns to persons. 713.12 Clay Flue Liuing (Inst"U"lion) Clay flue liners shall he in~talkd in accordance withASTMC 1283 and cxtend from a point not less IIHlII 200 JIlin below the lowest inlet or, in the case of fireplaces, from the top of the smoke chamber 10 a poilU above the enclosing walls. The lining shall be carried up vertically, with i.\ Ilwximum slope no greater (han 30 degrees (0.52 .rad) from the vertical. Clay flue liners shall be laid in medium ·duly refractory mortar conforming to ASTM C 199 with tight mortar joints left smooth on the inside and installed to maintain'lI1 air space or insulation not 10 exceed the thickness of the flue liner separating the flue liners from Ihe interior face. of the chimney masonry walls. r':-Iue lining shall be supported on all sides. Only enough IDm1.1r shall be placed to make Ihc joint and hold Ihe liners in position. 713.13 Addition,,1 Requiremenls
Ta ble 7JJ.16(1) Net Cross·Sectio nal Area of Round Flue Sizes Flue Sii'.c, Inside Dialllcicr (mill)
·- - ---- ·,5(f-- ---- - ······--- ·-·- i !i:()- ---·'· - -··- -175 .- --.. -.-- -- - --245--
___
-.------ 200 - - - - - -
~=~= .
Listed matcrials used as flue linings shall be installed in accorda nce with the terms of their listings an d the manufacturer's instructions.
713.13.2 Space Around Lilling The space surrounding a chimn ey lining sysrclll or vent installed within a maso nry chimney shall nOI be used to vent any qtbcr 'lppiiancc. Exception: This shall not prevent the installation of a separate flue linillg ill accordance with the manufacturer's instructions. 713.14 Mulliple Flues
When two or more flues are located in the same chimney, masonry wythes shall be built between adjacent flue linings . TIle masonry wythes shall be at least 100 mm thi ck and bonded into the walls of the chimne y.
32.3
.22.L_==_
.250_==-_ _~ ____ _ __ _ 275 __.__ ___ __ _-=5~8.~ 1 - --
- -1
1-----"3~OO----._I---.--_:_'7:=::2."'9c----
_ _ _ -"-38~0c......._. ___ _ _ _ _~11;.;;3"!:.5----, 460 163.9
NCI
Table 713.16(2) Cross-SecliollCli Area of Square and Rectangular Flue Sizes
Flu e Size, Outside Nomin:tI Dimensions (mill)
Cross· Sectional Area (mm' x 10') 114 x 216 14.8 .•.. - -'· --1 14 x 336 - - -- - · 21.9 203 x 203 27. 1 f--. -216 x 216 31.6 43.2 ._ __ 1 2 16 x 305 .. --". 49 216x330 305 x 305 65.8 216 x 457 65 .2 .. ~ 330 x 330 81.9 .._-J -305 x 406 84.5 111 .6 330 x 457 •.... f -. 406·x 406 11 6.8 - 143.2 406 x 508 ..- ------150~3----457 x 457 192.3 508 x 508 -- - _. 1---508x6 10 _. 216 .1 278.1 610 x 610
_-
_.
713.13.1 Listed Matedals
~-Cross,Scclionll l A;·~~3 (1ll1ll2 x 10 )
p
-~
Exception: When venting only Oll e appliallce, two flues are permittcd adjoin each other ill the same chimlley with only Ihej!J,it.! lining separation between them. The joints of the adj4.stf.i.t. flue Iini1Jg s shall be staggered at least 100 mm. .,
Association of Structural Engineers of th e Pllilippines
CHAPTEn "? . Ma sonry
7B.IS .Flue An.'lI (Appli:lI1ce)
7 ·· ~1
Figure 711. 16
Flue SizeS" for Masonry Chimne ys
ChiJl1Jll~Y flues shall not be smaller in area than the arca t)f the <.:OIIl1O<.:tOI' froJl1 the appliance. Chimney flue s connected to Illore than olle appliance shal! not be less than the arC,l oj' the largest COJlllector pills SO percellt of the areas or additiollal chimney connectors.
Exceptions: 1. 2.
Chimney flues servillg oil-fir(d appliances sized in accordance with NFPA 31,
",
Chimney flu es serving gas-fired appliances sized ill accordance with {h(' illfemaliollol Fuel Gas Code,
,,,
2 to I shall have a minimum net cross-sectional area o f a least 1/10 of the fireplace opening. Rectangular chimney flues with an aspect ratio of 2 to 1 or morc shall have tl minimum net cross-sectional are;] of at leas t dgof the fireplace opening.
713.16.2 Determination of Minimum Area The minimum net cross-se.c tiona l area of the flue shall be determined in accordance with Figure 7 I 3. J 6. A fi ue size providing at least the equivalent net cross ~sec !ional area shall be used. Cross-sectional areas of clay nue linin gs are as provided in Tables 713.16(1) and 713.16(2) or as provided by the manufacturer or as measured in the field. The height of the chimney shall be measured from the firebox floor to th e top of the chimney flue. 713.17 Inlet Inlets to masonry chimneys shall enter from the side. Inlets shall have a thimble of fireclay, rigid refracwry material or mctallhat wi ll prevent th e co nnector from pulling Oul of the inlet or from extendi ng beyond the wall of the lin cr.
'"
--
._._- -
--7"
-
"" ,,,.
_ .
"00
" ~ "
"
" " "
713.16.1 Minimulll Area Round chimney flues shall have a minimum net crosssectional area of at least 1/12 of the fireplace opening. Square chimney nues shall have a minimulll net cross-sectional area of at least I/loof the fireplace opening. Rectangu lar chimney nues with an aspect ratio less than
-
,~
'"
713.16 Flue Area (Masonry I'ircplacc) Fille sizing (or chimneys servi ng fireplaces shall be ill accord;mce wi th Section 713,16.1 or 7 13, J 6,2,
181)()
'"
" "
"'"
'" '00
,-
---+-- 1-- '"
- :----
713.18 Masonry Chimney Cleanout Openings Cleanout openings shall be provided within 150 mm of the base of each flue within every masonry chimn ey, The upper edge of the cleanoul shall be located al least 150 mOl below the lowest chim ney inlet opening. The height of the opening sh
E.xceptioll: Chimney flues serving masonry fireplaces, where cleaning is possible through the fireplace opening. 713.19 Chimney Clearances Any portion of a masonry chimney located in the interior of the building or within the exterior wall of the building shall have a minimum airspace clearance to combustibles of 50 mm. Chimneys located entirely outside the exterior walls of the building, including chimneys that pass through the soffit or cornice, shall have a minimum airspace clearance of 25 111 1ll . The airspace shall nOI be filled, except to provide fireblocking in accordance with Section 7 J 3.20.
Exceptions: 1.
Masonry chimneys equipped with a chimney tining system listed and labeled for use ill chimneys in contact with combustibles in accordance with UL 1777, and installed in accordance with the numufacturer's instructions, are permitted to have combustible material in contact with their exterior sur/nees.
National Structural Code of the Philippines 6
lh
Edition Volume 1
..",.
7·52
2,
CHAPTEn l . Masonry
Where masonry chimneys are constructed as part of masonry or concrde walls, combustible materials shall
not be in conlact with the masonry or concrete wall less than 300 mmJrom the inside sluface a/the nearest flue lining. 3.
Exposed combustible trim and the edges of sheathing materials, such as wood siding, are permitted to abut the masonry chimney sidewalls, in accordance with Figure 713.19, provided such combustible trim or
sheathing is a minimum of 300 mm from the inside surface of the nearest flue lining. Combustible material and trim shall not overlap the corners of the chimney by more than 25 mm
Figure 713.19 lllu~lrali()n
of exception three chimney clearance provi:;ion
713.20 Chimney Fireblocking All spaces between chimneys and floors and ceilings through which chimneys pass shall be fircblockcd with noncombustible matcrial securcly fastcned in place. The fireblocking of spaces between wood joists, beams or headers shall be to a depth of 25 mill and shall only be placed on strips of metal or metal lath laid across the spaces between combustible material and the chimncy. Table 703-1- Mortar Propo!1ions for Unit Masonry
._--
AGGREGATE MEASURED IN A DAMP, LOOSE CONDITION
PROPORTIONS BY VOLUME (CEMENTITIOUS MATERIALS)
MORTAR Cement -Ume
Mortar cement
._.Masonry cement
TYPE M S N 0 M M S S N M M S S N
Masonry Cement
Portland Ccmcnt Blended Cement I
M
OJ'
S
I
N
Mortar Cement N M S
-
I
---:-- --_.__. -:--
I I
_._. I
I y,
-~
I
I
-
over l/.j to 1/1 ovcr 1/1 to I l/.j ...-over I I;' to 2 1/2
_
Not Jess than 2 1;.\ and Ilot morc than 3 times the SUIll of the separate volumes of ccmcntitious materials,
---I
----~."
--....:-- __1...-
--j--
--
---_._---
----'--
I Y,
I ._. -_...-.
Hydrated Lime or Lime Puttr.... 'I<
-~
I
I I
-
0 I Masonry cement conforrnlllg to the requirements of UEe Standard 21 11. 2 Mortar cement conforming to the requirements of UBC StHTldard 2 J -14.
--
-
Tablc 703-2 - Grout Proportions by Volumc
t ...
I
TYPE
PARTS BY VOLUME OF PORTLAND CEMENT OR BLENDED CEMENT
----~--
...
...
"-.~.
AGGREGATE MEASt)RED IN A DAMP. LOOSE CONDrn9_N ..
PARTS BY VOLUr<.JE OF HYDRATED LIME OR LlMEPU1TY
---
-.-----.~-
Fine --_._._-----------_._.---~~---~~--.
-
2!f.! to 3 times the sum of the volumes of the ccmentltlouS mate! 1,lls 2 l/.j to 3 tUlles the sum of the volumes -- I to 2 times thc SUIll of the volumcs I to 110 of the cemcntitious materials of the cemcntitious materials Grout slMll atlalll a Jl1J1lI!llum compressive silength at28 d,lYS of 13.8 MI >.,\. The btll!dlllg offiCial may lcqulre ,\ comprCSSl\e ,dd strength test of grout made in accordance with UEC Standard 21-18.
Fine grout Coarse grout
I
010 I"
o
-
,
Association of Structural Engineers of the F'hilippines
CHAPTEH J ·lv1 asOI'II'Y
/ ·S]
Tabl e 704-1- Groul in g Limitations
- ... -- ....- ...- .· --····-MlNiMtJMj)ji;j£NSi()N.~-6V;mi:Tol;A I . CI.I" I< -~
AREAS WITltlN GROUT SI'ACES ANn CEI,I ,SLi
..._..~;I{()l2IJXJ~!L. __.._.~.;J{()U'I.!~.Q!!.l{ MA~.Iig~Q.Ul0.!!!!.~L~ ==~~.-.- '-------. r--=:=-~-'-~==--==-
'r;~,-;;---'-----r-'------'- )00 - -- - - - -- Fine Fine
_ _ .-.!'1ultl.wr.~~ Ml.':..~..t. ___. _ __ .. _llllllow ~~n;I:r~ ~~____ '" _
] ,500 2.400
35 35
15 x. 50 3S x. 50
Fil1e
),6CX)
35
45 x 75
Fine
7,200 JOQ.] ,SCX) 2.400 3,600 7,200
50 35
1)
Coarse
x 75 35 x 75
Coar.~e 50 (); x 75 Co;lrse 50 x 75 Coarse 60 75 x 75 Coarse 75 7S x 100 Sec also SCCllOfI 2 ] O:l .6. } 11\c ac tual gro ul space or grout cell dimen sions must be larger than the su m of the foll ow ing items (I) The required minimum dimensions of total c lear areas ill Table 704 ·1 ; (2) The width o f an )' 1ll0J1tU projections within the space: .. nd (3) 11,e horizont;11 projections o f the d iameters of the horizontal reinforcing bars wi!ilin II cross section of the grow space or cell. ~ Tile minimum dimensions of thc \Ol a! clear 'JI"ea s shaH be m:lde up of one of morc open ,lre;IS wilh at least onc arca being 19 mm or grcaLcr in wio!h.
is
Table 705· I . Specified Compressive Slrcnglh of Masonry, f", I MPa) Ba sed on Specifying the Compressive Strength of Maso nry U nits
I
COMPRESSIVE STRENGTII OF CLAY MA SONHY UNITS I,!
96.5
more
SI)ECIFlED COMPRESSIVE STRgNGTIl OF MASONI{Y, I'm Type N MOI·lar.l (MPa) (MPa)
'fype MOl' S Mortar l
(MPa)
-
.
.-
36. 5 32.4 27.6 23. 1
82.7 68 .9
,--
55. 1
41.3
26.2 22.7 18.6 15.2 11.0
18.6
33.lormon", 25.&
8.60
-···----Jo.T ------~
13.8
27.6 COMPRESSIVE STRENGll l OF CONCRETE MASONRY UNITS'·' (MPa)
19.3 --- _ ._----.. --- -·--13-.1 --
'- -'
--·-
SPECIFIED COMI'IlESSIVE STRENGTH OF MASONRY. f'. Type N Mor1 1Ir~ Type M or S Mortar) I (MPa) ( MP.) I
__
.
.-
20.7 17 .2 1).8
----- ~---
..ToY - --- --· --· .._ 6 .. 90
llJ.3
-_ ...._-
16, 19 1 12.7 9 ..30 6.. 50
.. masonry unus IS based on g loss area. Comprcsslve strcngth of ho !!ow d..ay nldsonry urllL~ IS based on nlll11lllum nct .\rCd . compress ive slrenglh of solid clay Values nl3y be interpo laled . When ho llow clay m,lsonr >' units .lre gro uted ,the grout shall con form to lhe prop
National Structural Code of the Philippines 6'" Edition Volume 1
1 ·501
CHA PTUi 7 .
M3~;ol1ry
Tabl e 707 - I - All owable Tension, 13/1 for Embed ded Am:hor Bo/(s for Clay and Co ncrete Masonry, kNI.2·1
(~;~a)
-~:-- EMBE~~ENT LEN(;~~!, t", ()rJm(;lfl)jST~NCE;~~~~~'~):==~~~~=:-~-=:-2~~I::~_:_1
,-l~ ---__-- _ __ 124 13_8
I!!_ _ _2~_ 1_25
----i-H--f
fI-- ___24;' __
I
-- ______ ------,.--;------- ----- -------- - -27:0-'I 6-76__________________......2-74 __________1_7~ ------__ _ ~_ ) ______ J..0}___ __ ______ J£:.."_____ ---..l2..!,_ -I
~ . ___
__
4_76 4_98
2_80
781
II 2
__
20_0_
312 __
: .~~
;!~
~~!---i]-- ---+H- ----~}---- --
27_6
1.78
3_96
7_08
I U)4-----_ -
15_9
344 41..3
1.96 2.146
445 4.85 -
7_92 8_68
12..37 13_ 53
17_8 19 ~5
28-~i------- -44-~i"
_
31.6 34_7
---- I
494 ---
'I
-~=_ ~_
allowable tensIon valucs In Tahlc 707- 1 arc based 011 compre ssIve strength or rn.lsonry a s~cmbl.lges. Wherc )'Ield slrength o[ ,me llor bolt the :lllowable fellsion in kN is g iven in Table 707·2 . 2 Vlllucs arc for bolls of 1II le;!!)1 A 307 qualify. Bolls shall be those specified in Section 706.2. 14 .1 ) Values showll arc for work with or without special inspection .
I
;H----j
--
I nlC
i
Sled
govcms,
Table 707-2 - All owa bl e Tension, Bf • for Embedded Anchor Dolts for Clay and Concrete Masonry, kN 1.2
~
I,
_ _ _ _ _ _ __ __ __ -'-A ""N =CHOR BOLT DIAMETER (111111)
6 1..56 I
J
12 6.27
10 3..5 1
20 14.1
16 9_83
Values arc for bolts of allcast A 307 quality. Bolls sha ll be tllose specified ill Sectio n 706.2.14. 1 Values shown aTe for work willI or with9ul special inspection .
Table 707-3- Allowable Shear, B,_, for Embedded Anc hor Bolts for Clay and Co ncrete Masonry, kN
J 'm (MPa)
10..3 12.4 ---13.8 17_2 20_7 276 34 .4 41.3
..
_._- --- - 10 2.14 2_14 2. 14 2.14 2_ 14 2. 14 2.1 4 2. 14
-
12 -3_78 3.78 3_78 3.78 3.78 3_7 8 3_78 3_78
!\_i'lCHOR nOLl'
1.2
DIAMETER (inches)
5.92 5.92 5_92
._--
-_~---l
---- --_._- --_.----------------- ---_.20 - - ----- --22 --- -_._-25 ---28 -- T77.92 8.45 9_12 -- 10_ 1 8_28 9..35 __ 9.57 -9)9 __ 8.45 9.1 7 --- lOA 9_70 11 .0 10..4 845 11 _5 10.1 10.9 845 12;1 11.7 8.45 10.9 l3~i 11 .5 12.3 845 12_9 J:U 11 .6 8.45
- ----_._----------
16 5.92 5_92 - - ----_._."5_92 5_92 5_92
, V ,\ I uc~ ,Ill. f01 i)()lts of-C--,1\. -ic,\sl .- _- - - ':-:-'_ A 307 quahty . BoilS sh,lil be those spec Ified 111 SCdIOJ1 7()6.2. 14.1.
--------~-
2 Values shown arc for work w ith or wit hou t specia l inspection .
Association of Structural Engineers of the Philippines
I
.....1
CH/\PTEfl 1 . M
.,
~I~)
Table 707-4- Minimulll Di ameters of Bend
..i
I
Table 70 7-5- All o wabl e Flexural Tensi oll (kPa)
!
MORTAR TYPE r-_~C~e~i~n~en~t~-~I~in~le~a~nTd~M~o~rt~a~r~C~e~"~l1~CI~lt~_-i.___ 77-~·~M~a~s~·o~nr~Ccnl~C~II~(~~---~ M or S
J
M or S
N
UNIT TYPE
N
I---;:;-,---"'T:':''-;-'--~'--:--+------r_------___.-- ------·-T---
Normal to bed Joints Solid
276
/-Iollow
172
207 131
----I
103 62
165
103
No rmal to head joints Solid
551
. . . . . ._-_Hollow ... . _-_._ - ---- - -_._ =222 -
267 330 262 2()7 _._-_._-- _ ._-- - -- --- - --------
Table 708-1 - Maximum Nominal Shea r Strength Values
,--
M IVd
V"
1.2
---_.._._ - -
MAXIMUM
Ii---r:::
50.25
6.0 A,1i I'm
2: LOO
4.0 A,liT,: 50 250 A, (214 A, Ii
50 380 A, (3 22 A,
-
207
.___--.!24_ ___
50 1691 A,
-
J'm
50 111 3 A,
,
!
M IS the Ilkl Xlmu m bendmg moment (h at occurs sImu!t,Ulcoust}, \\,Ilh the shear 10:ld \ al the section unde r considerat ion. Interpolation may be by straight line for MNd values between 0.25 and J .eX). Vn is in N, and 1'", is in kPa.
Table 708-2- No min al Shear Strengt h Coefficient
f I
~~V;i
f~
I
_j
M is the maximum bending moment lhal occurs simu!t,llleously with the sh ear loatl \f at the sectioll under consideration . Interpolation
may be by straight line (or MlVd values between 0. 25 and 1.00.
Table 7 l0-1 · Shea r Wall Spacing Requirements for Empirical Desi gn of Masonry
MAXIMUM RATIO Shea r \Vall Spacing to
FLOOR OR ROOF CONSTRUCTION Casl- in -p lace
Shear Wall Length 5: 1 4: 1 3: I 2: 1 2:1
CO tl C r c ( c
Precast Co ncrete Mew I deck with concrete iiI! Metal deck with no Ii II Wood Di aphragm
1h
National Structural Code of the Philippines 6 Edition Volume 1
_.-
'7·56
CHAPTEn!· Masonry
Table
710~2-
A!!owabJc Compressive Stresses for Empirical Design of I\1<1S011l")'
CONSTlHJC'TION: COMPRESSIVE STRENGTH OF UNIT, GROSS AREA
AIJ,OWABI,E COl\1PRR'iSIVE STRESSES GROSS CHOSS-SEcnONAI. AREA (r'ftPaj
~'-l)i;~M~~~srVi~~;t;;'r
.c-c.c---....
~~.-.-
..---.--.
Solid masonry of brick and other solid units Sand-lime or concrete brick: 55.1 pillS, MPa
2,41 1.55 1.10 0.79
31.0 MPa 17.2 MP" 10.3 MP"
Grouted masonry, of clay or shale;
~-~i~;iU;'r::fMOl"t;1 r
(;r da)-:·~;~:~<;h,~ic';~'"'~··'·
salld~limc
2.07
138 096 0.69
or concrete:
31.0 plus, MPa 17.2MP"
1.89 1,48
""I..,'"'--~-;c '-;-_ -;.c-_c";I0",.:c:eM
3 Solid masonry of solid concrete masonry units:
---:----~.-.----.-----
20.7 plus, MP" 13.8 MP" 8.27 MP" Masonry of hollow load-bearing units: 13.8 pillS, MP" 10.3 MPa 6.89 MP" 4.82 MPa
1.38 0.96 0.69
1.2 I
--.------~-----
138
L55 1. 10
1
0.96 0.69
0.79 .~--j-------'-"-'-0.96 0.79
---l
0.83 0.69 OA8
0.52 OAI
0.38
Hollow wa!ls (cavity or masonry bondedt solid units: 17.2 plus, MP" 1--;-:---:-:-,-1",0.",-3 M=..P,::..a_ _ _ _ _ _ _ _ _ _ _ .._.. __ , -:,H"o",ll"o-,W,-,;,"J:;-:li",ts:..·______ _____ _. __..__._-------_._-
,
LlO
0.96
0.79 - - - - - . - .. 0 52
0.69
--.------
Stone ashlar masonry: Granite Limestone or marble Sandstone or cast stone Ru bble stone masonry ."_..__ Coarse,_.~~ or rando-"m'--_______ ~_. _____ ~ _____. Unburned clay masonry
0,48 . -~
4,41
4.96 3.10 2A8 0.837 0.21
2.76 2.20
0_69, ---------_.-
Linear InterpolatIOn llMy be IIsed for dcter=;nj~~~g~II~;~~·~bk~i.~css~;f;~ mason;~ts havi;g~~;';~p~cssi-~~'"~'~-;:;-gtt;"s which-',!rc-Tr";u;'~'Tllediate Octween those given in the table. 2 Where floor and floor loads arc can-ied upon wythe, the gross cross-section;11 area is that of the wYlhe under load. If both wythes arc loaded, the gross cross-sectional area is that of the wall minus the area of the cavity between the wythes.
Tablc 710-3- Allowable Shear
OIl
Bolts for Empirically
Designed Masonry Except Unburned Clay Units
--.--~"".-
_______1_2_ _ _ _ _
..... ---~
Ion
L56
2A7
_ __
..... ---- --------: ~-~------.--..- ..--.------~ ··----4"'3"'~~'------j --~ 150-------· 4.45------6X7---------175----·- ·------5.56-·-18.2 2
.... ····--22------25
--~.--.---
..
~"--."----.--~
28
------------_._. _ _ _ _ _ :20~___________..!>'_62 __ ~~__
__._
10.0" _ _
An additional 50 mill of embedment shall be provided for anchor bolts located in (he top of columns for buildings located in Seismic 7...ones 2 and 4. 2 Permitted only with not less than 17.2 MPa units. I
Association of Structural Engineers of the fOhilippines
CHAPTErI ., . 1",1;\$()!1(Y
i :J 7
Table 71 0·4· Wall Lateral Su pport Rcq ujrc m <.~n l $ for Empiric.1I Design of Masonry ---- ----c~~~~~-
-::---c-_ -c'C",O,--,-N-,-,S,--,TIWC_"_rr_ON _________ _____M_A_X_I~_lJ_M _I/I _oIJ_ ,;/___ _ Bearing walls
Solid or solid grolltcc-I --------.--.
- --.,-.- ----.. 20
...- -...--.-18 ----------. ,----- - - --,--" ------'-"---.__.. _ - - - - _.._---_.__._- -- - -j--18 36 ~,--- ,----- --
All other _~9_~lhearing
-.-----~ - .--- ,, -
walls
Exterior
Interior
Table 710-5 - Thickness of Foundation Walls for Empirical Design of Masonry i
NOM INAL TIIICKNESS
MAXIMUM OEI'TI1 OF UNBALANCED FILL
(111111)
( Ill )
200 250 300 200 250 300 200 20 300 200
-1.22 l.52 1.83 1.52 1.83 2,13 2, 13 2,45 2.45 2,13
FOUNDATION WALL CONSTRUCTION
Mw;onry of hollow units, un grouted
- Mason ry (;f solid units
Mason ry of hollow or solid units, fully grouted
Masonry of hollow units reinforced vertically with 12 mm bars and grout at 600 mm o,c, Bars located not less than 115 mm from pressure Side of wall.
-,.. __..
Table 7 10-6 - Allowable Shear on Bolts for Masonry of Unburned Clay Units
DIAMETER OF BOLTS (mm)
--
12 16 20 22 25 28 -
I
C_
EMBEDMENTS (mm)
-
_.
300 380 457
- - --
-
.__ _____ 2.2.2..______ - -----.
600
th
SHEAR (kN)
0,89 1.33 1.78 2.22 2.67
National Structural Code of the Philippines 6 Edition Volume 1
_.-
--
----------,--_..
------- .--.~
Table 7! 1-1- Radius of Gyrat ion' for Concrete Masonry lJni t ~/
) The md ius of gyral iol) );lmB be based Oil ihe s pec ified d i.lllwsiolls o f Ihe masonry units or shilll be in ;u,:I:onl,lIICe w ith the va lue); shown wh ich arc based o n lI!c m in imuill di , "clls i on ~ of hollow n)llcrcte masonry unit face sht' l1s an d IYd)~ in aCI,.'()Hialicc wilh UBC SI(Uldard 2 1·4 for llYO cell UllilS.
Table 7 ! 1- 2~ Ra dius
~U T
SPA CING (mm)
._ - ,
or Gyralio n
I
for Clay Maso nry Uni t Lcngt h, 400 MM ~
NOMINAL WIDTH OF WALL (mm ) _ .__. .. 300 250 150 200 86. 10 4 1.65 71.37 5664 .._ .. _... .... _92.70 6 1.4 7 77.00 45. 20 .., .... .., . 63 75 95.80 47.00 79.50 97.80 47 .75-_.- _._.- 65.02 8 I .00 ··~-----sz:oO--- ' - 99. 1(1 '" .. .. ....'._48.50 65.80 99.80 49.00 66.29 .. 82.80 100.3(j 49.28 66.80 . .. 83.30 100.80 49.53 67.05 83.80 loi.35 84. 10 49.53 67 .30 ,-104.9() 86.90 51.31 69.8 5 .- . ~. -.
100 Solid Groutcd 26.92 400 29.45.,..__ , 600 30.48 800 31.24 · -..' ..' -' 1000 ..., - " '.. --_. ' -"31.75'--
._-
..
,
1200 1400 1600 1800 No grout
..-
32.00 32.26 ---32.26 32.50 33.53
for smglc wYlhe m"son ry or for ,Hlll1o l v ldu
r
,_
,
.. wall. or a C,.Vlly
=..,,) !lA ,.
~' I hc mdill s of gYI';lI ion shal l lx: based 011 Ihe specified d imensi ons I)f Ihl! masonry uni ts or shall be in acc ord~lIIce wi th the v alu c~ s ho wn which IIrC'. based (II I the minimum di ll1tllsions o( ho llow dny con crete maSQnry face shdls and webs in acct)rd
Association of Structural Engineers of the Philippines
Table 7 11-3- Radius -. -.- -- .- - -.--.- - .- - ,,-- -. ~ -
or Gyrati oo ' for Clay Masonry Unit Length. 300 MM'
- -- -- ------ _._- -
__~!-'l(}_lJ:I:_"~!' AC!.N_(;J'll'llL •..._---_._- --_._ 100
·. ----··-~~(~i'id Gn;uteu.---- -
----- -.._ - - --- - --"-_. __ ..
- - ----
- -- - --'-r ..
300 450 600 750 900 1050 1200 1350 1500 1650 1800
No grout
--- --
-
-_.
26.92-- - --
29.20 --- ------ 30.20---30.70 3 1.20 31.50 3 1.50 3 1.75 31.75 32.00 32.00 32.00 32.77
J ()f slllg IC-W} lhc masonry or for an IndIVIdual wythe ora C(lV lly wall.
r
-- _ .•._ -------- -_.•.._---_. __•...__._.- --- ---
NOMINAL WIDTH OF ".:~L L (mOl) ..•.-. __... ----- ---_..•._.. _"---_. _ ------. - - --_.-.-.-200- _.".... - _._ 250--- •.._- .• 150
---- --joo - -
".
41.90 45.00 46.23 47.00 47.50 47.75 48.00 48.26 48.26 48.50 48.50 48.50 49.50
56.90 61.00 - .. --- ------- 62.74 .. 63.75 64 .26 -64.77 65.02 65.28 65.53 65.79 65.79 65.79 67.30
._-«....
._-
.. _--. 86.60 71.63 9 1.69 ....._. 76 .20 - ---78 -23 == ·· ···· --94 23-- --95.50- .... 79 .25 80.00 -- - -- 9652 9706-~= 80.52 97 .54 81.03 97 .79 8 1.28 98 .00 81.53 98.30 8 1.53 98.55 81.79 : 9855 8 1.79 100.33 83.30 i
-
=-V' !IA,
Z111c radius of gyr:tlion sh;tll be ba sed on the speci fied dimensions or lhe Inasonr y unils or slmll be in :Jccord;ulce Wilh the valuC's shown which arc based on the minimum dimension s or hollow clay concrete masonry rilec shells and webs in ileeordanec with UBC Swndard 2 1-1 ror two ecl1 units.
Nalianal Structural Code of the Philippines 6'" Edilion Volume 1
AI APPENDIX A
CONVERSION FACTORS ----,--'"----.-
~-APPENDIX A: EQUIVALENCE BETWEEN SI-METRIC, MKS-METRIC, AND U.S. CUSTOMARY UNITS OF NON-HOMOGENOUS EQUATIONS IN THE CODE
- -. . . . . . . -.. --.. . -.--.. . . . ·--··. --·-· · . . ~--
~ . --
···~
SI-mctric stress
·· -·~l --
. . -..-.-----..---·· -. . . . ·. -·-------- --.--.--.-..------.--.-------.
U.S. Customary units stress i
mks -!l1ctric stress
_...______.__.__._ ....".""."....... _____________. . _. _.In M!~:.I__.____ .__. . ___. _". ._.~.~~.Y.£!"~~~_.__ I MP" 10 kgl/CID - --_....__..- ----.-~-:---------- -j- - - - - - -- -----;---,j', = 21 MP" .. /" . = 210 kgllclll-- ....... f'.. = 280 kgllclll/" . - 28 MP"
'j _._. _ _ _ •
..l?~:n~ls per square inch (ps.i-L .. 142 .2 psi .-
/" = 3,()(XI psi /". - 4,000 psi
/" . - 35 MP"
f'.. = 350 kgUcm'
/" . - 40 MP"
j", = 420 kgUClll -
/" - 6,000 psi
/;. = 2,800 kgUClll '
f, = 40,000 psi
f, = 4,200 kgUClll -
f, = 60,000 psi
I,. = 280 MP" f,:" 420 MP"
/" = 5.000 psi
-,•._---
---_._------ -_.. ,. - ---_. /,'" = 250,000 psi J;m ;: : 1.725 MP" /,'" =17,600 kgflclll ._---- -. - -._- ----- --_.. i,,,, = 19,000 kgf!c m/,'" - 270,000 psi /,'" 1.860 MP" -3. 18//,- in kgflcm~ 12/r, in psi f1' , in MPa --_. fl'--~11 kgfk~~~2-----3.77jf:" in psi OJI3 Jf': ill MPa \ , ._.... __.._------ .,--- --_._..• -0. 27 ji':- in kgfl(:Jl1~ \ r1', in psi 0.083 Jf': ill MPa . . ...,,-_.- ----- - -_._._...__..._----_ ...--_•.. __._-----
;:::
- - - _ ·- - - _ _ 0 ' _ _ -
0.170
Jf':
-o~5i/T.
in MP:!
/,,, - 1',. + 2.33s, -
Eg.405-2
-
- - - - -
In
2fT':
kgf/CIl1~
in psi
/", - /" + 2.33s, - 500
/" ., = /" . + 2.33s, - 35
1.5
--
1',., =J',. + 1000 1',., = 1',. + 70 - - --_._--- - ------_._._----_.f'cr - f'(· + 1200 /", =/" . + 8.3 /"., = J',. + 84 - .... _... - .--- •. -. f' ("I ::: 1.10[',. + 50 f'cr - 1.1 Of ',. + 700 /", - 1.10/',. + 5.0 .. _. .. ._..._------ .... - ... ..- .- .-.--...- - ... _-_ .. -"'--0.00 18;60 000 ----- .... 0.0018x4200 (lJ10 I 8x.'l1Q /" , =/" . ... 7.0
Table 405-2
.
. - .-. --~
_-_
---~- . -
Section 407. 13.2. 1 (3) Secti on 408.6.1
t.... = ",/'0.043 Jf':
E, = ",,'-' 0.14 Jf':
-----
I:.~= 15,100
(
E'I. 409-1 I
J. =f., /(0.5 6 Jf':) <:, 1.0
-
A = f,., /(1.78
(1.65 - 0.0003w,.) ;0:,1.09
(004 +/,1700)
--.-
_.._-- -
.I,.)
I. h ::::
(0.8,..- I[iii J .•. •.-..
.~------,,-'"
~.-
Eq . 4 10-3 Eq.410-4
Ji, '.- 4/,. b...
~
90 mill
_._-
I,
/f',.
.._--
( 1.65 0.005"".) ~ 1.09 (0.4 +f,JIO,OOO)
!
I, = 750)" Jf': 1
•
I
II
II :::: ----.-.-.•-- - - ;,:: 9cm
3(, + 9 fJ
I,
200.000
1
.
n. + 'r.) - ... (8 • 200.000 36~·9fJ
3fT:
......
200
A . = - - - b d ?-b.ll
A . = - - b d >-·- /) .d
S = 3{ 2800) _ 2.Se, :;; 3{ 2800)
S= l{
I,
I,
..-
/y
~
/,
Association of Structural Engineers of tile Pllilippin es
,.lJ\In
If
I
I
. =..- .-.-----.-....,. ;?, 3.5111.
. --
14
(08 ...
.~:~~~. EC:~:~.~~~[~-(;;·~:·~.·~~~}~~::~~_. ...
(08... [4.000 I, ) •
' .....n
,
33
J. =f;,1(6.70 Jf':) $ 1.0
1.0
(0.8 .... f, .... )
0.8//"
1.4
d ~T b...d
S = 38{ 280)_ 2.5e,. :;; 30{ 280)
/,
rr:) : :
1(1,1.5
£;. = 57,000 Jf':
" 14.000 II == 3'(;':;~'s/T(a--"-=-o'-i) ;: 12 .scm -........-..:---.--!:..:-.-~-.-.--...-... "'-I
361- 9jJ
A .
1
.
_--_..,._. . .: _ .::_i~:~~~~.~.:~~~,.:.:. ~:!.~ .~. .:.~~I~~_
Eq.409- 14
,JI';-
I, = 2.0)" Jf':
1 ( 0.8 + " 1400
Eq. 409- 13
E,. ==
(1.65 - 0.0003",,) 2: 1.09 (0.4 + /,17000) _____ _
I, = 062), Jf':
--_..._.'"...
I,
f,.
E = 4700 Jf':" . Table 409-1
_-
I,·
....
Sect. 408.7.1
__ __
... - /, ..
4~OO)_25<; :;;30t4~00)
AP-PENOii/i-: -EOTJIV flLEt,fCE BE'mEEN ST·METRIC~- MI(S:METRIC, AND U.S. CUSTOMAFIVTiNIT OF NON·HOMOGENOUS EQUATIONS IN THE CODE _._ -_._.• - ---- ro' -51- met ri c st r~ss
2
M".i.- I',,(15 + 0 .(311)
1''1. 410-1 8 -:~~1~4T1-:-2.
i--
-- --.-.~-. --.- - . -
E'I.41'1-3
- -- ---
---".
------- ------
U.S. Customary units stress ..£2.l:~~ls per sguare inch (psi) M?..mm = Pu(O.6 + OJ))")
mk s- mctric s lress
inMPa
-
f,' '" 8.3 MPa
in kgllc1ll M 2 .",,,, = PI« 1.5 + 0.0311)
- - -- -------.,--- -·----7/-"0 f,.' ~ 27 kgllc m-
-_..._-_._-- --_._-
V = 0.17!. f,.' b"d
V,.
--
I:~
----
= 0.53;;:- b"d
------_._-
v, =017(1 +
~ 0.291.
--
S 0.931. .fF: Ivi
.fF: b"d
E'I.411-7
~ =0 29()1 +~t).!jTb.d
V. =09{ \
Eg.411-8
O2 v. =0.17 ( I+ . : ,N" lAIT)" "~O
v.
E
-
--Eq.411-IO
Eq. 41 1-12
-.- -- -- Sec!. 41 1.6.5 .3
_
=0 53(I +Jf;}JT),,"~O
O, 17i.j1: b"dS. V,. "S.O.42J.rr..b"d
O.S3..!j1; hOod ~
,',
20
d +V ;- Y:M ..,~
"" r
M "w.
J
--_..
M'
~
Eq.411-17
j"
O.3Sb!.!.--1
(2)
7~,
(3)
\
.J!', b,,(1 fb A. .,,, . =0.75 fj', J S
~
V, =A,l, siIl6 ~ 0.8Jj,b"d
¢J.JTt~ ) ~-" p" 1+ o.33A, AIf:"
I
7:,<
"
SOb".!.
v,=
A,.j,. sina. ~ 3 j1, b"d
8 Jr,l)"(1 T,, <
-_...__._._._-_.
rfi..l.27 ArT , [A.~ .'.- )
--
Ii
1
- ( --;"A' pO.27 J. Jr.
<
+·V,
¢ 200
T,,<
1:,<
- 12 -
If 4.00 iT, b"d
2.2j1,b"d
•.. _...-
M"\J'
d
I'
y,
1,1
.~ ;'~L (~: ) F: -~:~~i~~-
Sec!. 411.7. 1
'"
M", =(6A.f{, + I." - IJ.!..
"
2: 3.s0",~
0.66,if, b"d
1AlC(::"l
-_._--_..
=0.20 ff""s f, --T'
7 ~f<
Sec!. 411.7.1
20
CO
400).
1.10 j1,b"d
A,.•,.
v, = A,.f,. sine! '" 0.25 j1, h"d
Sec!. 4 117. 1 (I)
V = 12A fi: b d +V + V, Me!! 2: I7J.Jl,b"d
¢O.53fi': b"d
b s
I'
--
1.10!.j1,
f,t
-------" Sec!. 4 11.6.7.9
2i./i b"d S V(5 5;,[f> .
v" ~(0.9'1t/T: +O.3/"h.d, + V; v" =l3.s;,fT +O.3f,.!).d"
0.33) j1,
A,."•• =0.062,J'T:
Eq. 411-J3
+~Mc~!".. M", ...
\' -,
¢ OI7 J f', IMI
(6)
J
~O
V =( 12Aff. + 700 V" " }," . 20 M,, '
2: 045J.j1,b"d
0.33j1,b"d . _ - ---- -_._- ----- - _ ._----_.-
Sec!. 411.6.6. I
+V I'
M",=(J6 A.f{, + I" - IJ.!..
=(0.29J.[i'; +-03/,."".d" + V"
v, = 2(1+ 5~~, )AJI':'b""
v, ~ 1.33;./J: /),,1'
=3.2J. E~b d 20
- _.
M", =(osA.f{, + /'. - IJ!... . )" \I",.
V ,',
}v~b."
V, =35( \/t+----"' "--50M,
V 2A V• =(1 . 20ff." 49 M~ ''')hd ~
2: O.14!.fj')J"f1 Eq. 4 1 I- II
~ 3.501..fF: b"d
- + 4.8 -" - b .d V, = (,Iff 20 M ,,'
V =Aj/, b
,.
-;~+9AJT. +250Op" ::/F~
"
F3-35A,". }"Tb." ."
v,, )
V, = 2.00!';:- b"d
-\~. ='2(1+--~---llfT;'-~-2000 A ."
l;iT
=05J[I+i:O~
b"" }JT h" " v. -------- -- - - ------ - ' ---" .•.._ -_. -- " ---V =( U .II>-<./T: +1 7p y"!')b" ( ~r V") 6•.<1 '" = 0.5 1'. +176P •.f.1 Eq . 4 11-5 .' • • M" • E'I.411-4
---
-.--
.
100 psi
'i'
9,1
II- " ( ...A'-". 1
-,._- .-....-,.- -...--.-..
¢A.{F: [ A;, )
+ -.--~'.
P"
;.ff.
1'.t<
I ;- - - " ( ' )h--
¢0.27 A -Arr-
N
-~
A~Aff(
Pcr
th
P 'P
r"
-.~ .~.----.-.
7:, <
r--1,:-
"" 1
j
f 'c""
4.l /f',.
T"<
¢A ( -A:' ) F 1+ --"N -
National Structural Code of the Philippines 6 Edition Volum e 1
Per
4A.J..ff
A3
'APPENDIlC(:- EOUlVALENCE BETWEEN SI·METRIC. ·MKS·METRIC . AND U.S. OF NONHOMOGENOUS EQUATIONS IN THE CODE
CUSTOMARVUNIT
Eq. 41 1·25
E 50b ....\'
> 3.5 b •.s
=
I",
1.33/1'>'" _[.1)1.
""""
E". 4 1 1·30
-
1
r
.
I
.\.,
/.1'1
. .--.---==-"'---------.-1\.",,, =sf )1,' p"
)
F;"', -(;
I"
.~ > ~~~~ s - /" ------------ ~~~~~----I-----~~~~~ --~·---~~~~·~--··----
(34 + O.OS};' )A,.
(3.3 + a.OS};.' )A ,.
(4S0 + O.OS};: )A,.
Sect. 4 11 .S.5
IIA" 1 lOA" 1600A,., 1~~~~~______~5~.5~A~'·'________i _ ______~ 55~A~,~,______~------~S~ OO~A,~,--.--------
Sect. 411.9.3
2.65
0.S3 jl'b"d . (3.3 + D.OS}; ' )b"d
Section 411.10. 3.2.1 Section
ff b"d
(4S0 + O.OS};' )b"d
1600b"d':-,---;-_ _-I (800· 2S0a ,.)b"d d !
110b"d (55 · 20a •. )b"d d ,-;:;265" /" lid
~
Section
10
b"d
"""{34 + D.OS};' )b"li
11b"d (5.5 . .L2.,q,'j7)"d d
41 LlO. 3.2.2
J/"
7"-~~:-;-,------j-----;-:c=-,--;;-;=-:-;-'7-" -'"
(5/6)y/',. li d
r r . - " I,
1O \1/', lid
......i.'.IJJ.)_ ..._ ....._ _....________ _ ._ ..__._ . ___....._._ _. _ ..___________.. . _.__......._~ , . r('-;-
Scction 411.11.5
0
(11")1. ,, . ,. lid "--
- _.. _----
......
_.._---- - N d
Eq.411 ·33
t/= 0.27,1 .j (' hdl -- "
Eq . 41 1·34
•
'
. ,
- ---- -
'/-f" ,hd
53, ,,
f'-
N d
... _.
2' /--1 ' I I , " , l( -_.--- - - -----_._--.--_ .
V =08S,1 ,1' hdl·-" ' 41"
41,,'
r -
N d
1' = 33,1'1(' hd + - '" ' '4/".
1-----..·----,----- -~---_c,~,~~--~---~-~_4-7"--~---~. rr 1.(01 A./l:+02;',)· r- 1.(03Y..fi.+02N.)' . j" 1('25l,/],;'0/') v = uOSl!L.+ __ .. ____ L lid v= Q J 6i~&. + .. _- . - - - -IJ!... lui v= 06lL+-\----2!.. lui
2
M• • I.
~2
•
2
M..f.. \~2
'
.
2
M•• I•. \~
2
L.... _ _ _--L_-'~_.____._.._. _____ I___=__ ______ _~'____'__'_._ _ _ ______ .:._......
Association of Structural Engineers of the Philippines
I ,
A. 4
APPENDIX A:: EQUIVALENCE BETWEEN -SI-METRIC, MKS-METRIC, AND U.S. OF NON HOMOGENOUS EQUATIONS IN THE CODE
CUSTOMARY UNIT
I~~~~~~~'~~~~~~~~~~;~-~'---"---~~-----'------
Eq.~11 -37
HI·'ft).lJT>..d
v. "'
II. = 053(1+ '~).1ji',b..d
v, •
- -- - . _-- - - _ . - - - _.. _..._._ - - - - ----- - - ---- -_._ ....- - - _._...... G.
CAJ.
V• =u2-1.I£'+2) , /j. . ,. bd 'l /{, '''l!."
V• =12 . I('2'+2)"j . . ' . bd I~. 1\.1. ",
41 1 3"
-.0
(2+ ·~).1H·~b.. "
.._- -
--j
II' I="(':l'!+2)'/f '- bd , A,J., "
Eq.4Ti~9 -v-~J.i.Tr ;;~·;f · -- - \;---::-~7T'-;;:~/' --'Eq . 41 1-40
II. = 4J. JJ':"hOod ~,).jr:- '03f," h." + v,. --- I e=(J.16/!,J.jl': +o3f,Jh. d + v, v, =1fJ,J.jl-~(;·.-3f-~·)/;b-Ood-+-V,----1 Note:
Il,. bas units
f--;;--cc---+---;' =/~____ Seel ion 411..13.2 . 2 Secti o n 411..13.3 . 1 Secti o n 41 !.I 3.3 . 2 Sectio n 411.1 3.4..8
!r,
5 0.50
0 . 17.1
Mr.
Note: IJ,. has th e same un its as The Sf-metri c version 55 kgficm'
fj',
jf',
1.I0lf:b"d
4lf:b"d
If: h" d 0 . 80), If: h" d
If: h" d 3), If: b, d
2.1O fT.:b"d
SJr, b"d
:5 70 psi
If: h" d
0 . 50jr, h" d
0..33Jr,/)"d 0..58
Sect ion 411..13..5.1
iT,
0.25),
h" d
190
If: h" d
0. 66 !1':· 1",,1 0 . 17
If:
053
2
L6¢ ff 0 . 53(1), ff 0.53¢), ff 1.l0¢'\ ff
If: < 8 . 3 Mra
JJ: :5 26..5 kgficm
050¢
r-iY-" 13. 7..2 Section
7
If:
ff Ol7¢1.ff 0. 1 7¢»,ff 0..33¢)' ff
Secti on 41 !.I 3 . 5.2 Secti on 411 .13 . 5,,4 Section
41 1.13 . 7.3 Section
Note,: /lphas units
If:
6¢ ff 2¢J. ff 2¢ J. ff 4¢J. ff
~--·---I------~==--~------~~----~
-..!'.~;?.:.~.- --- --~.- -----. - - .-- -.-.... Section 412..3 . 2
/ _ ( f,.'!',VI, )d ,- 2.IAJT: "
Section 41 2..3..2
/
'
/
=(
,
=(_ /,'1', '1', )d
--- - - - - - , - - - - -- , - - --1
f ,'I','f, ")d
6.6AJT,
/ _( f ,'I','I',
ff :5 100 p,i
2
/
•
,
t
-'-)rI
f,'I','I'
25J.ff,·
/' =( 20J.ff,· f ,'!', '1', )d / =( 3f ''!'''!'')d , SOA.ff, ,
, - 5..3A..JT: J"
L7Aff, ,
=(
J~~~--+_----_7--~~.----_l--. ----~-~~~--~------_7--~~--. --~
Secti on
41 2.3 . 2
~~~t~o~ Eq . 412- J
Section 41 2,,4. 2 Section
412 . 6 . 2 '--_ _--'_
/ d
/,
=( 1.4J.ff, f ,. 'I','I', )d '
/
,
----I -------7---~-----4
+~';ff: },'
V" .V'I / "'" __. ___/_,_V~!_
.... ,/
=( 4.4f,.'!','I', )d A.ff, "
I"~ =(3~fg.~}, f ),If, VI,If,
I
I., /
, - lIJ.Jrt'~~) :_. _ _7"._=_3. _5-c.1J_f_~_"r_c:_:: .K:_::-"-r_'_
[~J7) ", > 0.043/ ,<1, /
=
[0.24\1', &. ) d
/
=
~---1
3f,Y',V',If.
/
_!---_;_'_~_4~",).i:-j-f-':(,-C-·d. :; .;:R--,)-'-'-~
(°J.~H') ". ~ OOO44/A.
/
=( ::~ff.:}.-....
(~~H d, >O OOO3[,. d,
(~m5\1',iL) d
d~ A.fT b ~),I1;-; . ~ _ _ _ _ _ _ ___--'-_ _---'---'---'---'_---1_
(O. 02¥,i, )
_
Jd~ = Itff d~ _ ..:......'---'-_
. National Structural Code of the Pl1i1 ippines 6'h Edition Volume 1
_
.--'
A·S
APPENDIX A: EQUIVALENCE BElWEEN SI-METRIC, MKS-METRIC, AND U.S. CUSTOMARY UNITS OF NONHOMOGENOUS EQUATIONS IN THE CODE _ _ ~ __ _ _ ~~ ____________. _
d~IC~~(~1 ' :I~~(~;-
''' ' [~7F!J d, --- ----- .-TJ;~,241-- - --- ---- -
_._- --_ . Eq.41 2-3
-~Oq 412-4
VJJ'NTJ7;~) I, =( if}";( r"fc}.
Seclioll 412.11.5.2
.0.4111.-'
Section 412.14.2.2
O. J7d,JJI
1---_ __ .._ ------"...,;/~,:... , -:---_ _ _
Sec,ioll 412.1 7.1 Section 417.6.3.1 and 417.6.3.2 Section 417.6.3.3 Section 418.4.3
,,, = [O~7J' J d, --
1, ~rOO,i;'('J'J d,.
--F~;~~Or ----" - -
" =;·hj7~·J
--- -----_._._----_._.-
,,"027;:'{dj·,·J
=(to)". +( ~c7~L}.
I"
I,
O.053d bf)"
0.014<1,,1'1
O.(Xl73 !,db (0.0 13 (. - 24)d"
0.0005 lA, (0.0009.r, . 24 )d"
--~'ff,
OJ)7! J,db (0.13,{.. - 24)d"
-
;.ff,--
O.55b,.d
( 1.8 + 0 .60.(..))..b,d < 3.5b,.d Class U: f, 5 0.62!fc Class T: 0.62
JT < f, 5 I JJ~
80b,d
( 18 + O.6p,[,.))..II,d ~ 35b,(/ Class U:f, S 2ji, Class T: 2
JJ:
Class Cf, > I.0ji,
Class C:f, > 3.2ji,
50 Jr:.
f, :5 1.6 Jr:.
°
(260 + 0.6e-f.'))..",(/ :S 5(Xlb,Ll Class U:f, S 7.5JI', ClassT: 7.5!fc 12
f,
I-~c---j-----=_---I-------=_-.-.-.......r;:-;-
""-
Y /,,; - - 1 -- 025 -..:.::...::...- ......
f
=f 1""
f"
.700 +._1_,_' lOOp,.
=
and 418.10.3.2
Section 4
2 l b.d
s 6Jr:.
--=_-
6.JT:.
-
----;
_
7 -'- ..-.-I - -- - --...c"",'---- .f" + 70 + JOO"f = f + 700 + -f'-~--_~~_l-----~~..:.::. p!...,_ _+ __"__"_ 300P r Sect 418.10.3.1 0 17 .Jf': 0.35.Jf': Eq.418-5
rt;
3 .J /,,;
080 V /,,;
__
f 1" = f " ;. 70+...L:.... lOOp,.
. --
160[J~;
0.50[/,,;
Section 418.5.1 (3) Eq.418-4
=(~}. +( ~oT£}~
+ _ _._.."...:.Il:.,,~-----+----::~/,:...,-,--- ----i
;.ff,
f, :5
1_
"' -'-(i_~ ;,'·; '; ;r --- ·-
~..bL
I ' + ---'-/ /" = / " +'0000 ' JOOp p --~-f-'--"
-'-/ P' = / " +'0000+ , 300p,.
2.Jf': 300 bJ
1-""1,-8_.1.,.3_.7_......;1-_ _ ,-..:.1..:.,~.~~---+--~-=-/..:.>- =c- . . ._ __+ _ _ -,--..:f_c>~-c-..c-=,------i Section J", = J" + 70 J", = J" + 700 Jp, = f" + 10,000 418. 14.4. 1
Section
o 33¢J..[i',
1.1
¢?.Jf':
4(Mff
_. ..:c4~ 19~.5~.1:=..0______---,--,-'-c-c-__ -.- - -I- - --..,..,..-- -- -Section
.1A b,,!~.
i - - . -- - -- - - - 200-",., <1.
!...4..I",!!..
1 1-421.5.2.1 -- ----lI - - --'I.2.,'.---~----- - -----'-',:.., . _·_-,--_·__ 1_____f-2.._...._.... · _ _.._ Eq.42 1-2
-,, =IOO +(350 - h,) 3
.'.= l o l( 15 ~h,)
S, = 4+(~; h,_)
1.7.f1'~Aj
5J/f';A,
--+___..:4'--"'.in"-.",<~s''-''<=-6~in!:.._ _ 20JiA
l.2"fT>j
4.0ff,A j
1 5[i~Aj
I.Off,A;
32{i':Aj
I2{i':Aj
100 millS So < 150 n,-",lIC.'ll_._j_--,I,-"O~c~·n.'..1<~S''-' ' <~.~15o.:c,"n'CI_ _ Section 42 1.7.4.1
Association of Siructural Engineers of the Pllilippines
Sectioll
421.8 _2.2 V.
+
v. =AJa,J...jJ, +pJ,)
=AJa).fT; pJ,.) II
II a,. = O.80for~: :s 1.5
a .. = O. 25for/~ S 1.5
Eq .42 1-7
h
at" = 0.17/0(1: ~ 2.0
o66A
Section
421.8.4.4 I-"",Sc- c-:-C- lio n
a,
.f f
a" = 2,Ojor ': 2 2.0
212ANff
O.83A,,,.ff
8A,,·ff
IOA,.ff
2.65A, .. f f -
-
..-.----Ir--------'~f7----.-
- --':G"=.-
0-83A''' vf,
Secti on
II
It
=0.53for ,:"~ 2.0
----- - 1-- ----"=-- ---+- - - ----''=- .-.-- -n
-i- - - -----r,;--- ------
421.8.45
v. ='\. la,;
2.65A,,,vf,
2.8
IOA, .. ,f, 400
28
421.8.6_5 (I) ___ _ '--' I ,_ _-=~---j---.:.I'-,_ -=0--_ _--1 _ __ ---'1-'--,---;=--- ----1 ~oo ~ ~ O_083A".A,17 f, O_27An. Ayf, ANA,}, 421.8_6_5 (2)
I Eq_421-9 i Eq- 421-10 I
I
!
I I
Section
421.9.9_2 Section
42Ll 1.6 Eq.422·2
V.
=A,,(O.I7J.fr: + M,)
V.
°66A"ff 029
=A,,(0.53J.fr: + M,)
V. = AJ2J.fr: + M,)
8ANff
212A"ff
JT'>.d
0_93
Jr>.,d
35 ff: b"d
Eq_ 422·7
1
Eq.422·9
r
Eq_ 422-10
Y, =OII(I+%)..tJ!')"" "0022), ff: boil
v,
=035(1+%)..tJT,b." "0 0_7 I) .fj~ boh
1h
Y, =(~+ 3~),jJT,b." "0 2-66'-ff: b,il
National Siructural Code of Ihe Philippines 6 Edilion Volume 1
II-?
APPENDIX II CONVERSION FACTORS
--- -_._.
,-- -. ----.~-- .
--------- - - ---
to _:=.:~_~==_____==~=:=::~. _____
To convcI1
~-- . -
.--J ,m
LENGTH
I mile (U.S . sl,ttul')
I yd I fI
2.589998 0.4<>1 6gn
h.
0.8)6 1274 0.092 903 '"
!Il
01'
mill VOLUME MODULUS OF SEeTI!>"!._
1 acre ft
645.16
m
-
I yd'
i
0.764 5549
0.2359737 0028316 g5 28.3168
m'
I (I)
L(dml) I in)
16387.()6 16.3871
mm' mL (ern)
(FLUID) CAI'ACITY
L"'·
I gal (U,S. liquid )· I qt (U.S. liquid) 1 pi (U.S. liquid) I n 07.. (U.S) 1 gal (U.S. liquid)
_.
-
-.
3.785412 946.3529
rnL mL mL m' U I liter appf(lx. OJXJI cubic met('.r SECOND MOMENT OF AREA
~~Hon (UK) ~2l?rox. 1.2 Gal (U.s.)
1 in
0. 158987.'\
Illl
I barrel (42 U.S. J:al!ons)
.-~--··-I
1233.489
m' m'
100 board ft
473.1 765 295735 0.003785 4 12
-_
...._ --
! :~~
1 4162314 "4 162314x 10"
PLANE ANGLE I " (degree)
r(ld
1 ftls
1 mile/h
SPEE~ ____
1.609 344 0.447 04
mls VOLUME RATE Qt' FLOW mJ/s Us Us
O.oz8 316 85 0.47 1 9474
0.0630902 0.0038 1.051 SO 43.8126 1233.49
mJ/min
mUs Us
1 million gaVd I acre fUs
_._-
m)/s
_. __ ._~.I:EMPERA TURE INTER VAL °Cor K
- 1°F . -
I
--J 0.555 5.%
I
'"
(Colltlfllled)
.~
.....-
- -- I toF= 9/st(,("+32
Association of Structural Engineers of the Philippines
.----~.".-.,
.. .
----- ---.---- ..
sJ9 "C = %K
EQlJIVALENT TEMPERATURE (I,.-=T.-27J.15)
-_.-
. _--
I 0.3<>18
knvh
I rt Is I ftl/min 1 gaVmin I gal/min I gallh
....<0-.._..
17.453.29
29().8882 4.g48 137
urad
VELOCITY mls
.-
0.0174';3 29
mrad urad
l' (minule) J" (second)
.. _j I
4046.873
Ill' 2
I (12 I in2
-
.601J .:14r---
--_.. _. _. -_."_._- ~~-.-..--~----.--.--
kill
I yd2
~~.ti:ip'ly-b·';·-·::·_
)<>1H
AREA
-
I mi le' (U.s, SIJlllle) I acre (U.s. survey)
-- 1
0 .9144 03()4S
_________ _____ ___ __ iii:::
._1_;_"___ .. _. _____ __
-
----
A8
AI'I'ENJ)JX II CONVERSION FACTORS--{Conlinued)
, 1ibJ(i'l-'. - - -- ----- - - -- - - -- - --
4.8S2 428
33.905 75 305. 1517
I Oll}'tJ' I o7Jfl l
-,;-;:""_ __ __ _
- ) Ibm J
._ _ _-1
DENSITY (MASS PER UNIT VOLUME)
·----------==='-'-=r.k:=g/7n'-"r==~-""===-------r-;176."0" 1 8",7 6 -- --
J Ib/yd' I lon/yd J
kg/Ill) v rn )
0,593 2764 \.1 86553
FORCE I tonf (to n ·f{)rcc ) I kip ( 1,000 Jhf) _.~ lbf (pOU!~_:(~~~ _ _ ___.__ _
kN kN
.. ___ _~
8.896 44 4.448 22
= ='7N;,..,==-==-= ,-=_-==
4.448 22 _ ._ _ _ _ .____._
-;1·"lIc;,f.7ft-- -- - - ------- - -- - - _-"M"O",M,,,"-"'E"N-"TIr'or.:':::",, ~O~R-"C"'E'-,T-'-O "-.., R"' Q"'U"'i,,'-_ , ·-_--_-_-_·-_-----.---.--"-.- -'-1".3"5'5'81"8Ilbf·in I tunf·ft I kip,f(
-
N'm kN·m kN.1l)
- --.---
I lbrlfl J lbflin 1 10nyft
- --
- ---1
0.1129848 2 .7 11 6-1 1.355 82
FORCE PER UNIT LENGTH -- ..-------~"""T~"'-'-'-'-"-"'-"''-'-''-'-'-'------,__;_:;_;;;_;;;_----_i [ N/m N/Ill kN/m
_
J 4.5939 175.1 268
_-:-::-'::"29" .,IS,,7"' , 80:-T."'_ _ _ _ _ _-l
PRESSURE, STRESS, MODULUS OF ELASTICITY (FOR CE PER UNIT AREA ) (1 I'a = 1 Ntm' ) Iionflin'
MPa kP, MPa
13.7895 95 .7605
I lonflrt 1 I kipfm2 I Ibf/in~ 1 lbflfl l Atmosphere-
Pa kPa
6.894757 6.894 757 47.8 803 101.3250
kP~
I inc h mercury
kPu
3.376 85
I foot (water colunlIl at 32"8
kPa
2.98898
-;-;=-== =o;:,-_____._____ ._____.\'-'VORK, ENERGY:1IjiEAT (lJ = IN·", = !~ ·s)____........____ I kWh (550 ft.lbOs)
I'
I Btu (inLTable)
k.J
I fl·lbr
j j
-- - - ------- - - 3.6
1.055056 1055.056 1.3558 18
COEFFICIENT OF I1EATTRANSFER I lhul(ft ·h·"F)
I WI(n,'· K)
I 5.678263
THERMAL CONDUCTIVITY WI(m·K)
ILLUMINANCE
National Structurat Code of the Philippines 6'" Edition Volume 1
1.730735
NSCP C101·10
SPONSORS AND BENEFACTORS OF ASEP WHO HAVE SUPPORTED THIS MONUMENTAL TASK OF PUBLISHING THIS CODE
Association of Structural Engineers of the Philippines Suitc 713, Futurc Point Plaza Condominium 1 11 2 Pa nay Avcnuc, Quczon City, Philippincs 1100 Tel. No : (+632) 410-0483 F ax No.: (+632) 41l-8606 Enlail : .<[email protected] Wcbsitc: http://www.ascponlinc.org
National Structura l Code of the Philippines 6'" Edition Volume 1
JOEL MalUllln UDINA, M.M;-;:-··-~
.
Conau!llng Structural Enllilloor5. SIE 153
DAM C. ABINALES. "'-'>110. Insoo Managing Principal JOHN OLIVER D. PENANO. nmoo Associalo Partner Office: UG48 Cilyfand Pioneer Cond 128 Pionoer S1..,l.~artdaluyon[j.9.!Y_
U
Address: Blk 6! 1. La! :l4, l'llasc 6 MelrO{jlllC Moycauayan Ii LDG Marilao l3ulac
~~~:II~::~~;~v~~;;o~c~9n~2'8328864
GILBERT B. MAGBUTAY, ... , .o.5EP
GISMA Englnef)rlng SCrvlces
Address: 93 Kalikasan SlIoe!. Karaogalan Villaoe Phase 2A Dela Paz, Pas~ Cily 1611
Phona: (02) 682-7114; 517·1159 Mobile: 0920·9226441; 0923·3917297 Email: [email protected]
ALLAN DERBY A, ALFILER, ... .ASfP
A.D.A ALFILER EnglnoorlnQ Consultant"
Addloss: l100nl 31'. 3JF Aliloo 8reln 1191 Quirino HiQhway No~alictlOs, Qualon City
Phone: 416·3059; 419·0136 Mobile: 0920·9235232: 0922·8235232 Email: adaallileroc@yahoo,corn
1'11011(1: 425·7076
J
ASSOCIATION OF CIVIL ENGINEERING ALUMNI OF NATIONAL UNIVERSIrY--(ACEANU) Phone: 749·6154; 743·7992 Email: [email protected]; Addross: 551 M.F. Jhocson 81" Sampaloc, Manila
:~~:~~p:~::~~~:;::~~~
"CHRrsroPRER·PT.T~YO, f. o\5~p
MIRIAM LUSICA-TAMAYO, _ _
_._--_.
Adam. Abl.nales £nO;<1oo,j"o 8. COnsutlanCY PhOflO: 746·8156: 502·4223 Mobile: 0908S72-2326; 09!75~2'2326 Email: aaopluscyahoo.com: mlo@aaepl\lsc,corn WObsile: www.aaolllusc_com
Addross: 4/f. 15781riQa SlrM\' Makati City
TandeM Englnooring Consultancy PhOM: 890·2022: 896·6930 Email: [email protected]
. ~RYT:-WONG .....0.5€p
Address: Shop !22 AI Tawila Bldg .. Juliair, Manama, Baillail1
Email: wcenghoy2001@yahoe.. com Websile: kooheii·onll;nOClinll-collsullafICy.cOr!l
VIRGILIO B. COLUMNA,. '" ....,
V.B. Columna Construction Corporation
Address: 1133 Azucena St. Violela Village, Sla. CruZ. Sixlo Bulacan
H.T. WONG,
Address: Chunics Bklg. (lower ground lit). 3368 1'1. Mflgs~ysay Blvd .. Manila. f'hilippinos
Phone: 712·2201: 712·7025 Mobile: 0917·5379654 Email: halrytingwonQ@yalloo,com
ANTHONY VLADIMIR C. PIMENTEL. F• .o.5EP
Pimentel & A.$soc lIes Eng neer n8 Consu tants
Address: GfF 430 Mafigaya III Bldg,
E. Rodriguez Avonue,Cubao OuewnC'
Phone: 721·7391: 722·6278 Mobile: 0926·2600094 Email:
p::~::\_~~:::~~~~~oc.nol'Ph:
-RUEL B. RAMIREZ and ASSOCIATES
CANETE STRUCTURAL INVESTIGATION, INC. AIIx!r1 C, Cailctc, ... seE.
RUEL RAMIREZ,
f. ASE!'
t.lSC~,"'_.0.5(r
Add,e~s;
Uoil20l, Joe!"r Bldg. Comrnonw(!a~h A~e" Quewn Cily
[>hono; 931-5214: <153-5151 Facsimile: 951·27(; 1
Address: U2F Maginhawa 81dg" 154 Maginhawa 51.. Sikaluna Village, QUOl.On Cily
--~~-----.-
MEUSA A. RAMIREZ, .... .0.5EP ~"""""\lr"1'''''
P'''''r..o: f ''o>W11
Phone: ~33·9313 Mobile: 0920·90901 4 7 Email: rt;ra._eng'@yahoo_com
..•..• ---.
---------
EDMUNDO P. TUMACA--·-~---E,f).TUMACA ENGINEERING SEfWICES Address: Quozon Ave .. Kalioo Aklan
JOSE T. TAYAMORA
PhOM: (036) 26B 6076, (036)2589020 Mobile: 092131979134 Email: [email protected]
Address: 84 2nd Floor General Espino St.. Zone IV, Signal Village, T3{1uig City
Phone: 666· 1087 Facsimile; 638·8351 Mobile: 0939·5214051: 0939·4755915 Email: [email protected]
.
SMART MASONRY PHILIPPINES, INC. Address: P3b B 12 L 13 Eastwood [.
Greenview. 6rgy. San Isidro, Rodflgue~. R,!ai
ALAN C. ABAN, f . .l.5EP
DANILO RElUCIO
Address: CIC Compo\lnd Francisco Feli~ Ave_. Cainta. fkal
Pilone: 655·5429 Facsim;le: 655·7671 Email: [email protected]
~_.
•
____._ _ _ _ _ _ _ _.-L
1108 Antel Global Corporate Ctr" Julia Vargas Ave " Ortigas Clr. . Pasig City Tel. No,: 638-3414 to 24 Fax No,: 916-3740 Email: acs_manufacturing@yahoo .com Website : www.acs-manufacturing.com
ACS MANUFACTURING CORPORATION
PROKRETE Concrete Admixtures
"Ve make good concrete a better concrete.
Unit 401 4th Floor Lancaster Hotel, #662 Shaw Boulevard Mandaluyong City, Metro Manila, Philippines 1500 Tel. Nos. (+632) 571-8668 t070 Fax No. (+632) 571-6285 Email: [email protected] Website : http://www.ddtkontract.com.p~l
DDT KONSTRACT, INC. CONTRACTOR.
ENGINEERS
MISSION: We will steadfastly strive to provide good services to the need of our clients through quality and timely delivery by pursuing excellence in every aspect of our services. We will continuously support and enhance the well being of our hardworking workforce to meet the challenges offered by expanding market and stronger competition. We will continuously enhance a management vision to remain a partner in the development of our society and country. GOD WILLING
Sales Office Address: Unit 2104 ANTEL GLOBAL BLDG, Julia Vargas, Ortigas Center, Pasig City, 1600 Tel. Nos. .667-3278; 633-3474; 633-3477 Telefax Nos .• 667-3279; 667-3281
•••,..•'. II ~ l! Q, 1l- lYJ< 6, ~,
6ltft c:;
.
1258 Sandoval Ave" San Miguel, Pasig City, 1600 Tel. No.: 643-7802 Tel. Fax: 640-0698
DEECONCRETE
INCORPOKATED
C. Raymundo Ave., Caniogan, Pasig City, 1600 Tel. No.: 641-7919 Tel. Fax: 642·8020
••..".,.. ." If!1 4' q, 'Jr'i - .!If!;J<::1li. Z,Jtf, Ii; •
Purok Uno, Baranggay Makiling, Calamba, Laguna
PRIME MOVERS OF QUALITY CONCRETE.
PR£CI$'4N 11.£ A .ltH·,." '-JfC. ~ ~~
www.energy.com.ph
energy
DEVELOPMENT CORPORATION
Thlrty.four years In the Industry says a lot about a company. Our able staff of geoscientists, drillers and engineers Is In demand for both consultancy and actual wor1< In geothennal exploration and development. This enabled us to become the largest focused producer of geothermal energy in the world. Globally recognized for our knowledge and expertise, EDC is now at the frontline
wet steamfield technology and geothermal energy production. At EOC,
we know green energy and we make it happen.
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Executive Offices · No.12 Manggahan St. , Brgy. Bagumbayan , Quezon City 1110, Philippines Tel. No. : (632)635-0843 : (632)635-0861, (632)635-0609 , Facsimile No. (632)635-0612 E-mail address:[email protected] Website Address : http://Vv''WW.eei.com.ph
EEl CORPORATION
EEl Corporation is one of the Philippines' leading construction companies. Long years of contracting and collaborating with global contractors, particularly in the Middle East and Asia Pacific countries, have enabled the Company to achieve wondcaliber project management and construction expertise and competencies . EEl possesses the broad capability to undertake construction contracts from design-andbuild, lump-sum basis to labor and construction supervision services across different classes of projects. It is the major provider of construction services to the power, oil, gas and petrochemical, Infrastructure property and Industrial sectors. As it continues to undertake major projects in different industries both here in the Philippines and abroad, it is likewise contributing its share in the country's national development and progress.
PGA Technical Center No. 85, Kamuning Road Quezon City 1103, Philippines Tel. Nos .• (632) 929-33-52 to 55; (632) 929-17 -86 TeleFax • (632) 929-33-53 Website • pgatech.com.ph
PGA TECH GROUP "YOUR ONE STOP SHOP FOR ENGINEERING & SUPPORT SERVICES"
NON DEsmUCTIVE TESTING l.ABORATORY. INC
E-mail [email protected] Phone #'s: 632-929-34-05 Fax #. 632-929-34-06
E-mail Address:[email protected] Phone #'s: 632-929-33-53/929-33-55 Fax #. 632-929-33-54
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~A Geopie," P(JAo.<>p'''' PIuJf('1'tl_
m.o
E-mail [email protected] TelelFax #: 632-372-79-48 Exclusive Licensee GEOPIER Technology
I
E-mail [email protected] Phone #'s: 632-371-18-03/371-18-09 TelelFax #: 632-372-79-48
PGA EARTH STRUCTURE SOLUnONS
,,_ Exdum, PnlfilOO D~nM"HGRID c.osln~'ocs
E-mail Address:[email protected] Phone #'s: 632-927-09-84 Fax #. 632-929-33-54
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Head Office Address: 5/F Benpres Building, Excllanga Road cor Meralco Avenue Ortigas Ctr. Pasig City, Philippines 1600 Tel No. ; +632 910-4111 Fax No. +632 910-4141; +632467-9018 Vlkbsite • W'N'W.firslbalfour.com E-mail ; firstbalfour@firstbalfourcom
First Balfour Excellence In Engineering & Cons1ructiOn
First Balfour is committed
1969·
to providing wond-class construction services for eMI,
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The company has the ability to design and construct various worns in coordination with its pool of designers fi'om diverse disciplines.
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Website : www.hilti.com .ph
Reliable fastening. Anytime. Anywhere.
Anchoring for 5tructural applications Hilli anchor solutions that address the issues of load bearing performance in different concrete strengths, steel strength reduction, loosening of nuts & progressive displacement in earthquake and/or dynamic load influenced applications Post-installe
Head Office 7th Floor Two World Square McKinley Hill, Fort Bonifacio Taguig City Tel: 459-3333 Fax: 459-3425 Ready Mix Concrete Plants Taguig Plant Barangay. Ibayo Tipas Taguig City Tel +632409-7933 Parafiaque Plant Km. 16 Severina Industrial Estate Bicutan, Paranaque City Tel: +632821-3306
I
Holcim Concrete
Strength.Performance.Passion
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Headquarter OFFICINE MACCAFERRI S.p.A Tel. No . +39051 643600 Fax No.: +39051 0512365 Email: commit@maccaferri .com Website: maccaferri.com
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Philippines PHILIPPINE GABIONS, INC. Tel. No.: +6328130211 Fax No.: +6328130211-1 Email: [email protected] Website : philgabions.com
Philippine Gabions EnvironmentalSolutions™
The Officine Maccaferri Group is a global player in the research, design and manufacture of advance solutions in geosynthetics and soil erosion control. Started in 1879, the experience gained makes Maccaferri a reliable problem-solving partner for soil stabilization, slope reinforcement, erosion control , infrastructure development, and construction works. Constant research and exclusive know-how enables Maccaferri to guarantee maximum innovation and efficiency, and these concepts are transformed into versatile solutions to meet customers' specific requirements. Maccaferri manufactures and distributes a wide range of geotechnical products, and provides services to compliment a broad range of drainage, filtration, reinforcement and erosion control applications in the fields of civil and environmental engineering.
Philsteel Tower 140 Amorsolo Street, Legaspi Village, Makati Philippines 1229 Tel. No.: 813-8382 Fax No.: 840-2123 Email: [email protected]
. I .Phil m eta I A
Philmetal
~~,~.!~~~~.~~.
The aest In Steel Decking Technology
STEELDEK SERIES: Steeldek I, Steeldek II , Steeldek IIA, Steeldek III (Designed to endure anything. Used in SLEX SKYWAY & MRT.) STRUCTURAL ROOFING: Colorbond Megadek, Colorbond Super V Dek, Colorbond Crimplok, Colorbond KLiP-LOK STEELFRAME SECTIONS; Studs & Tracks, l.C & BC Channel, Ceiling System
Unit 810, Pioneer Highlands Condominium Pio~er cor. Madisons Sts, Mandaluyong City
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Pozzolanic
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REPUBLIC CHEMICAL INDUSTRIES, INC. CONSTRUCTION PROFESSIONALS SPECIFY PIONEER PRO
Adhesives, Sealants, Coatings, Waterproofing and Painting Preparations for your construction needs,
Unit 2309 Cityland Condominium 10 Tower II, 6819 HV Dela Costa St., Salcedo Vi llage , Makati City Tel. No.: (632) 894 5067 / 8922140 Email: [email protected] ranni [email protected]
R. S. ISON & ASSOCIATES
Consulting Engineers
RONALDO S. ISON Civil/Structural Engineer
• Office Adress: Unit 2204-0, 22/F West Tower Philippine Stock Exchange Centre Exchange Road , Ortigas Center Pasig City 1605, Philippines Tel. Nos. : +(632)631 3075/6378286 Fax No. : +(632)6378236 Email: [email protected] Website : www.systraphil.com
SYSTRA PHILIPPINES, INC.
SYSTRA PHILIPPINES, Inc. or SPI was created in 1995 as a Joint Venture undertaking of JAVLON International Philippines, Inc. (JIPI) and SYSTRA SA in France. SYSTRA S A is a limited liability company whose main shareholders are the Paris Transport Authority (RATP) and the French National Railways (SNCF). RATP operates the Paris Metro and is considered one of the biggest urban mass transport operators in the world while SNCF operates the country-wide railways network ill France. SYSTRA has over 50 years of experience in 140 countries and boasts of a solid reputation of uncompromised professionalism and technical faculty. According to the year 2001 survey carried out by the Engineering News Record, SYSTRA ranks first among international design firms in the mass transit and rail category. SYSTRA operates on major international markets whose activities cover all the skills and expertise in the field of urban and rail transport - from high speed trains to buses, to intermodal transport, conventional rail, suburban or inter-city rail services, metro, tramways, automatic guided systems, road guided systems and people movers.
Offlce and Plant
2E San Andres Street, Canumay, Valenzuela City Philippines
SatttUite OffIce 1108 C.M. Recto Ave Manila. Philippines Tel. Nos, : (632) 292-7049; (632) 292-7050 (632) 292·7052 Fax No : (632) 292-6780 Email : [email protected] Website : www.unltanconstruction.com
UNITAN CONSTRUCTION a DEVELOPMENT CORPORATION
