Simplified Methods on
BUILDING·CONSTRUCTION
MAX 8. FA.JAAOQ JR. B. S. Architecture, National University 1961; Passed the . Boord Exam for Architects 1961; Former Deon College of Architecture and Eng in~ering, University of North Eastern Pl)ilippines; Architect, . Public ';tNorks Province of Comorines Sur; Practising Architect and Contractor; Author and pu~ Usher of S'implified Construction Estim~te_
Philippines Copyright
1983
by
MAX B. FAJARDO, JR.
All Rights Reserved Every copy of this book must bear the genuine signature of the author. Copies not having the signature will be deemed to hove emanated from on illegal source.
FOREWORD Experienced builders agree that Building Construct ion is considered os the most challenging, complicoted and articulate work in the field of construction. To discuss the subject matter embracing the whole aspect o~ b_uilding construction from the laying out up fo the lost touch of the finished work requires· several volumes. The author in this f irst volume presents the rudimentary knowledge os well os the techn ie:a/ aspect and procedur~ of building construction. The book was designed to present the technical trade in-formation in a short, concise, d irect and plain language accompanied with illustrations os o visual aid to the reader. Useful tables, conversion foetor and formulae from the English to the Metric System (Sil, various permit forms, problems and solutions were also incorporated. Hand tools, power tools and equipment including their respective uses and functions in the construction were also p re- . sented because the author considered those to be the first one a builder should be fam iliar with before any other thing in the construction. The book could be of great help to Architecture and Engineering students as well as trade school stude nts, carpenters and laymen who ·have interest in the field of construction. ·For the first.vqlume, the author wishes to express his grateful acknowledgement to the. valuable research and contributions. of PepinN . Fajardo, and also to the constructive sugge~t ions of Supervisor Jhonny Blonquera who first read the preliminary . manuscript. The author likewise expresses his indebtedness and gratitude to the persons here unnamed wro in one way or another hove contributed to the full realization of this book.
M. B. F.
}•
TAILE OF CONTENTS CHAPTER I 1·1 1-2
1-3 1-4
l -5 1-6..
1-7
l-8 1-9
1-lO I -ll 1-12 1- 13 1- 14 1- 15
Mea suring i ools . . . .•.. •. . . .. . .. .. •. . • ... .. Marking Tools • .• . . •... .. . •.• . ..• . . .. . .. . Testing and Guiding Tools • ... .••. .. •..• •.• • Fastening Too I5. ••• • •.. •• • • •.. • • • • • •• ••• •• • Rough Foc:ing Tools . . .. . . ....• . ..... . .... Toothed Cutting Tool!> . . ... .. . . .• .. . . .•• .. .. Sharp-Edged C~tt i ng Tools .. . . . . .. . . . .... . Smooth Facing Tools . . ...... . : . ... .. ..... . . Boring o r Drill ing Too ls ... .. . . .. .... . . .. . . . Holding Tools ... .•. . . .. . . . . ... . . . . .. . .. .. Sharpening Tools . . . . . .. .. ... . . . . . .. ..... . Work Bench .. .. .. . .. .. ...•• •. .. . ...•... Roughing Up Tools .. . . .. .. . . .. : . . . . ... . . . Surface Finishing Toofs .. . .. . .. \ .... . ... . . . M iscel laneous Ma son ry Tools . . . . . . ...... .
CHAPTER 2 2-1 2-2 2-3
2-4 2-5
4!-6 2-7 2~8
2-9
TOOLS
2 5
6 12
·13 14 19
22 26
29 31
32 33
35 37
WO 0 0
Introduction ... .... .. ... ......... ,,. .. ... ~· .,,. ,. :.... . . Definition of Terms .... . .- .,)••··-"' . . ... . . ..... .,.•,..._. Classification of Wood .i . . .r • • • ' ·' . . , •• • • • , ,.,..,. _ Preparation of Wood . . . .. .. ·" . . ..• . . . ... .. , ,__, , Defects in Wood .• .... ., ••. , ..• , ... .. .... ... .. , . Of~ Seasoning of Wood . .. .. •.... .... • .. . .... . .,,... ~ Causes of Deca y and Methods of..F!JeServotrtm. --:':'J Measuring of Wood . •.. .. , . ... . ... .... ..... . ,. . Eng lish to Metric Measure o.f'· ~ --~. ,_.. ._. • .;.• . .
CHAPTER 3
Page
42 42 43
44 45 46 47 49 51
LA.YOUT AND EXCAVATIONS .
3-l
·53
3-2 3-3 3-4
57
De finit ion . . . •... . ....• • ... •. . •... .. . . . .. . Lay'out Method s c;m d Procedures .. .. ... ... .. . M inor ExcCtvation ... . ,. • ... ..... •. . . .. .. . . .. Major Exca va tion .. . ... . . . . . . . . . : ......... . J ... Sheeting and Bracing Sha llow Excavat ion .. . 3-6 Sheeting and Bracing ·of Deep Excavation . • . Sheet Piles ..... . ..... . ..... .. ... . ..... . . 3-7 3-8 Exca va t ion in So nd .. . .... , . . ......... . . .. . 3-9. Excavation in Clay · . . . . ... . . . •.. . . .. ... ... 3-10 Filling · ... . . .. .. . .. .. . . . . .. • ; ... . . . . ..... .
s
53 59 61
63 65
67
68 69
CHAPTER 4
C0 N C R ET E
Concrete ........ , ............... , , ...... ~ .. Cement ........................... ~ ...... . 4-3 Aggregate ...............•................ Water ......................... , . ~ ........ . 4-4 4-5 Types of Concrete ond Their Weight ....•..•.. 4-6 Mixing of Concrete .............•.......... 4-7 Segregation ............................•.. 4-8 Requirement for Good Quality Concrete ..... . Curing ............................. , . , .. . 4-9 4-10 Admixture .............................. . 4-11 Concrete Proportion and Water Cement Ratio .. 4-12 Tests ................. ·...................... . 4-1
4-2
CHAPTER
5
Steel Reinforcement .........••......•... , . Steel Bars ·from English to Metric Measure .... Prestressed Steel •..•••••.•.•••........•..•• 5-3 Welded Wire Fabric ..................••... 5-4 5-5 Identification of Steet Bars ................. . 5-6 Bar Cut Off and Bend ·Points ..•............. Bar Splicing ................•....•... ; ... . 5-7 Bar Spacing ........•....... .' ............. . 5-8 Concrete Protection for Reinforcement ....... . 5-9 5-10 Bundle of Bars ....• ; ..•.•.....•............ 5- J 1 Control of Crocks ......................... . S-12 Metal Reinforcement Specifications . . . . . .. 5-2
6-l 6-2
6·3 6-4 6-5 6-6 6-7 6~8
6-9 6-10
6-ll
6·12 6·13
72 72 73 76 76 77
78 78 82
METAL REINFORCEMENT
5-1
CHAPTER 6
7J 71 71
86 87 90 91 91 93 94 94 95 97
98
98
F 0 U N D AT I 0 N
Brief History ••••••••••••••••••. Wall Footing ...•........•..•..•...... , ... . Isolated or Independent Footing ......•..... Combined Footing ..••..•....•............. Continuous Footing ..•.......•...•........• Raft or Mat Footing ......•........•....... Piile Foundation ........•..••............•. Piles •••••••...••..••.•••...•.• ............. . The Important Functions or Uses of Pile~ ... . Quality and Durability of Piles .•..... , ..... . Timber Piles .....................•....... Deterioration of Wood Piles .............•.. Protection of Timber Piles .................. · !
......... .
100 102
102 106 107 107. 109 109 110
112 113 114 114
6-14 6-15 6-16 6-17 6-18 6-19 6-20 6-21 6-22 6-23 6-24 6-25
Pile Dr.iving .................. .. .... .... . Con.rete and Pipe Piles ...... ·.... ........... . Precast Concrete Piles ............ -. -.- ... . Deterioration of Concrete Piles ....·.... ..... . Metal' Pile ....••.... - .. ,. .. : . •.... . . . . . ... Driving Equipment· •..........••••... : . ... . Pile Spacing .............. ........ ........ . Driving of Piles Through on Obstruction ... . Causes of Pile Deflection in Driving Settlement of Foundation ............. . .. . . Failure of Pile Foundation ................. . Grillage Footing •.•............. ·.......... .
CHAPTER 7 7-1 7-2 7-3 7-4 7-5 7-6 7J7 7-8 7-9
115 118 119 119 120 120 124 124 125 125 126 l27
SOIL TEST
Auger Boring . . . . . . . . . . . . . . . . . . . . . . . . . . . . Wosh Boring . . . . . . . • . . . . . . . . . • . . . . . . . . . . . Hollow Stem Auger Boring . . . . . . . . . . . . . . . . . Rotary Drilling ........•....•..••... : . . ; . . Percussion Drilling • . . . . . . . • . . . . . . . . . . . . . . Penetrometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dutch Cone Penetration . . . . . . . . . . . . . . . . . . . Vone Shear Test ..... :. . . . . . . . . . . . . . . . . . . Standard Load Test . . . . . . . . . . . . . . . . . . . . . . .
f 28
128 129 129 130 130 130 131 182
CHAPTER 8 POST AND COLUMN 8-1 8-2 8-3 8-4 8-5 8-6 8-7 8'-8
Definition . . . . . • . . . . . . . . . . • . . • . . . . . . . . . . . Wooden Post . . . . • • • . • . . . • • • • • . . • . . • . . . • • . . Rein'forced Concrete Column . . . . . . . . . . . . . . . T ied Colu mn . . . . • • . . . . . . . . . . . . . . . . . . . . . Spiral Column . . . • . . . . . . . • . . . . . . . . . . . . . . . Composite ·cotumn . • . . . ... • . . • . . . . . . . . . . . . Combined .Column . . . . . . . . . . . . . . . . . . . . . . . . Lally Column .. . . .. .. .. .. .. . .. .. .. . .. . . .
CHAPTER· 9 9-1 9-2 9-3
9-4 9-5 9-6 9-7
13'-4 134 136
137 149 159 160 l 61
PLATFORM- FLOOR STRUCTURE
Wood Floor System • . . . . . . . . . . • . . . . • . . • . . . Beam ...••. .. ....... ..•• ..•••..... .. : . . . Relation Between the Materials and Structure . . Behavior of Beam Under the Influence of Load . Reinforcement of Concrete Beam . . . . . . . . • . The Compression and Tension m a Beam . . • . Spacing of Reinforcing Bars in Seam ... ·~ • . • .
162 165 16.7
l69 170 171 173
9-8 9-9
9-10 9-11 9-12 9-13 9- 14 9-15
9-16 9-17
Splicing Hooks and Bends .. .. .. .•• .- •••• •.. 174 175 Steel Bors Cut Off 'o nd -Bend Point ......• • .. 176 Beams Reinforced- for Compression •. ••• .• .. 177 Web Reinforcement ....... . .• . ...... .... . 177 Tor&ion in Reinforced Concrete Member •.•• . • 178 T-Beam Design & limitation , • • . ••.•• . ... . . 178 Other Causes of Beam Failure ...•.•....•.. ~einfarced Concrete Slob .. ....•.•••••.••• . . 179 Ribbed Flood Slab . ...... ............... ..· 186 189 The AC I on Concrete Joist Floor Construction .
CHAPTER 10 · STEEL FRAMING 10-1 10-2
Introduction . . .. . . . ..... . . . ..•••••.... . .. Structural Shapes . . ....•. • .... . • . .•• .•. ... 10-3 Structural Steel ... . ....... . .. . .. . ........ . 10-4 High Strength Steel ....... .. . ..•.... . .. .. . Rivets and Bolts . . . . . . . . . . . .••.•.... . .. .. l0-5 l0-6 Riveting Procedures . . ... ... . ....•.••..... . 10-7 Conditions for Punching and Drilling •.. : ... . Bolts ~ . ...... .. . ...... ..... ,. .. .•• _ • : ... ... . 10-8 Connect ion of Structu ral Members .... . . ... . 10~ 9 10-10 Plate Girders . .. .. ... . ..... . .. ... ..... . .. . 10-1 1 Web Plates and· Intermediate Stiffeners ..... . 10- 12 Roof Trusses ........ . ............... . . .. . 10- 13. Welded Connections .•...... .. .•.... .. .... . CHAPTER 1.1 11-1 11 ..2 11 - 3 11 -4 11-5 11-6 1 1-7 11-8
195 195 196 196
197 200 200 206 207 211
212
TIMBER ROOF FRAMING
Introduction . • . . . . . . . . • • . . . . • • . • • • • . . • . . Types of Roof .. .. . .. .. . .. .. • . . • • .. .. .. . .. Types of Roof Frame . . ....• ... , . . • . . . . . . . . . T imber Framing Fasteners . . . . • . . . . . . . . . . . . . lntf!rmediate Joints . . . . . . . . . . . . . . . . . . . . . . . . End Joints ·• . . . • . . . . • . . . . . . . . . . . . . . . . . . . . . Splicing . . • . . . . . . . . . . . • . . . . • . . . • . . . . . . . . . Glued Laminated Lumber . . . . . . . . • • . . . . . . . .
CHAPTER 12 'ROOF AND 12- l 12-2 12-3 t 2-4 12-5
190 191
215 216 220 225 228 231 233 235
ROOFING MATERIALS
Roofing Materials . . . . . . .. .. . . • .. .. .. • .. .. Galvanized iron Sheets ... . . . - .............. Corrugated G.J. Roofing Fasteners·......... . Advantages and Disadvantages of G. I. Rivets . . Advantages and Oisadvcntagess of G. I. Nails . :
242 243 246 247 247
Technical Specifications .•. . .•.....•....• . .. 248 Plain G.l. Sheet ...••...................... 249 252 12-8 . Flat, Standing Seom and Botten_Roofing ..... . 12-9 Slope of RooF • . . ... . . . . . . . . . . . . . . . . . . .... . . . 252 255 12-lO Cloy Tile Roofing ... . .... ... ....... .. ... . . 256 12-1 1 Asbestos ond Color. Bond Roofing . .. .... .... .
12-6
12-7
CHAPTER 13-1
13-2 13-3 13-4 13-5 13-6
13-7
13
STAIRS
Introduction ...•.•••.............•...... · . Definitions . . . . • . . • • • . . . . . . . . . . . . . . . . . . . . Laying Out of Stairs ...................... · . laying Out the Stringer . , . . . . . . . . . . . . . . . . . . Type of Stringers . . . . . . . . . . . . • . . . . . . . . . . . . Handrail and Balusters . .. .. .. . . .. . . .. .. . .. Re inforced Concrete Sta irways . . . . . . . . . . . . .
259 259 263
263 265
266 266
CHAPTER 14
PRECAST AND PRESTRESSED CONSTRUCTION ·Introduction . . . . . . . . . . . . . . . • . . . . . . . . . . . . . Types of Precast Structure ....... . ......... . Roof and Floor Members ....... ..... ·. . . .. •.. 14-3 14-4 Precast Beams •.••••••••• • .•.. .. .•. .. .•.• 14-5 Precast Column ................... .. .•... 14-6 Prestressed Concrele .................... . l4-7 Prestressing of Concrete ........ ... ... .. ... . 14-8 Concrete for Prestressing ... ............. . . 14-9 Shope of Prestressed Structure ... . ......... . 14-10 Metal Rein:orcement .. .... .............. . 14-11 Grout for Bonded Tendons ...... .. ... ..... . 14-12 Measurement of ~restressing Force .. .. . . ... . 14-13 Post Tensioning Anchorage . .... . .......... . 14-1
J4~2
CHAPTER 15 15- J
1-5-2
~5-3
15-4 15·5 15-6 15-7
269 269 270 271
272 272 273 275
275 , 280 282
283 283
FORM, SCAFFOLDING AND STAGING
Form . . . • • . . • . . • . . • . . . . . . . . . . . . . . . ... . . • . . Construction ,f forms ...•.......... ,' ,.:. . . Erection ond Securing of Forms . . . . . . . . . . . . Wall Forms ...•••..................... ·. . . . Greasing of Forms . . • • . . . . . . . • . . . . . . . . . . . . Comparative Analysis Between tke T&G ond Plywood as Form . . • . . . • • • • • . • . . . . • . . . . . . Scaffolding and Staging .. • .. • .. .. . . . . . .. . ..
284 285 287 288 288 289 290
15-8
Stag ing for Reinforced Concrete Beam and Floor Slob • . . . • • . • • . . . . . • . . . . . . . . . . . . . . . . Conduits and Pipes Embedded in Concrete
15-9
293 294
CHAPTER 16
HOISTiNG EQUIPMENT and POWER TOOLS 16- 1 16-2 16-3 16-4 16-5 16-6 16-7 16-8 16-9 16- 10 16-1 1 16-12 16- 13 16- 1-4 16-15 16-16 16-17
Hoist • . . . • • . . . . • . . . . . . . • • . . . • . . . . . . • . . . . • Definitions . . • . • . . . . . . . . • . . . . • • . . . • • . . . . . . Knotting and H 1tching . . .. .. . . .. . . . . . . .. Pu lleys .....•. . ..... . ...•....... . .... .. .. Circu lar Sow . . ........... . ... , . . . . . . . . . . . . Radial A rm Sow . . . • . • . . • • . . . . . . . . . . . . . . . . . Portable Electric Sow . . . . . . . . . . . . . . . . . . . . . . . Portable Electric Drill . . . . . . . . . . . . . . . . . . . . . . Drill Press ·. . • . . . . . . • . . • . . . . . • . • . . • • . . . . . . Portable Electric Sabe r Saw . . . . . . . . . . . . . . . . Band Saw • • • • • . • . • • • • • . . . • . • . • . . . . • • . . . • Single Surface Planer . . . . . . . . . . . . . . . . . . . . . Portable Sanders . . . . . . . . . . . . . . . . . . . . . . . . . . Porta ble ·Hand Router . . . . . • . . . . . . • . . . . . . . . . Wood Lathe •. ..••..•• . , • • . . . . .. . . . . . . . . . . . Truck Mounted Crane . •..• • ........ ~ , . . , . . . Tpwer Crone . . • . . . • . . • • • • . . • . . . . . . . . . . . . .
APPENDICES
... .•... . .....•.•...... , . . . . . . . . . .
297 297 298 304 · 306 31 0 311 3 11 31 2 3 13 3 14 31 7 317 318 319 320 321 322
CHAPTER
1
TOOLS INTRODUCTION Tools had been regarded as a partner of man·s quest for progress and survival from the early stone age down to the present generation. The mechanical advantages, accuracy, speed and efficiency derived from the use of the right tools and equ ipment, has prompted man to continuously search for the refinement of old tools aside from the invention and introduction of new ones that would provide greater efficiency and refinement of work. Comparatively, it could be seen from the structures and works , of past builders, the quality. refinement of texture and the time involved in their construction to be far behind the wor ks of the present generation. These could be mainly attributed to the kind of tools and or power tools that are being used by the present contemporary builders Experienced builder agrees, that the efficiency of the work in building construction could be augmented by 25 percent or more with the use of the right kind of tools aside from the improved quality of the work performed. By hiring an experienced worker who has a complete set of tools however high his demand for pay is more advantageous and cheaper than hiring a beginner with a lower rate but without the . necessary tools for a particular job. The former although demanding a higher pay can accomplish wor~ with better qu-a lity in a 5hort time than the latter whose work r isks repair and delay not to mention the extra cost involved. The efficiency and quality of the work particularly in building construction depends upon three factors: 1. Avai labi I ity and sufficiency of materials. 2. Experience and skill of the workers in their respective field. 3. Complete set of too ls and equipment of good quality and standard make. The different kinds of construction tools may be classified according to the different kinds of trade involved:
1. Carpentry Tools 2. Masonry Tools 3. Tinsmithing Tools
4. Painters Tools ·
5. Plumbing Tools 6. Electrical Tools
A- CARPENTRY TOOLS Carpentry tools are classified according to their functions:
1. · 2. 3. 4. 5. 6.
Measuring Tools Marking Tools Testing and Guiding Tools Fastening Tools Rough Facing Tools Toothed Cutting Tools
7. 8. 9. 10.
Sharp-edged Cutting Tools Smooth Facing Tools Boring or Drilling Tools Holding Tools 11. Sharpening Tools 12. Work Bench
1- 1 MEASURING TOOLS The early developed measuring tools used in constructions were of various types provided with English-measure graduated scale into 8th. and 16th of an inch. The forerunner in making · these kinds of warranted tools are the Stanley and the Lufkins Rule Co. The increasing popularity and worldwide acceptance of the Metric measure has prompted these companies and others to adopt and incorporate the meter and centimeter rules in all the measuring tools that they are manufacturing. The recent measuring tools appear to contain the inches on one edge and the centimeters on the opposite side of either the zig-zag or push· pull tape. · Consequently, the worldwide adoption of the Metric System otherwise known as the System International (SI). manufacturers of all kinds of tools has to change the scale and graduation ot measuring tools from English to Metric measure. However, although the Engl·ish measuring tools are already obsolete, they are still presented in this topic for historical background. How the present tools developed the correlat ion between the English and the Metr ic measure, their equ ivalent values, how they served the past generation and how they used the instrumen-ts which could be of help to the educational background and advancement of the present crop of builders. The different kind,s of measuring tools that are being used in building construction otherw ise known as "Rules" are; 2
•
1. The two foot four folding rule 2. The Extension Rule 3. Zig-zag Rule
4. Push-Pull tape rule 5. Slide Caliper rule 6. Marking Gauges
The two foot four folding rule - is generally used in measuring short distances. It is usually made up of four folds connected by three hinges spaced at 6 inc;hes or 15 em apart wh ich could be ' folded-up.
Figure l-1
a~
Extention Rule - Is used for measuring inside distances such doors, w indows, cabinets etc.
Figure 1- 2
Zig-zag rule - Is ava ilabe in (4 ft.) 1.20m and (6 ft.) 1.80 m commonly used by carpenters fo r ro ugh layout. There are three types of joints available : 1. Concealed 2. Riveted 3. Springless
Push-Pull Tape rule - Is used to measure long distances; available from 1.00 m to 50 meters tong.
tio-zoo rule
Figure 1-3
Slide Caliper rule
Is used to measure outside diameter of
cylindrical objects.
SLIDE CALIPER IIULE
Figure 1-4
Marking Gauges- Is used to make lines parallel to the edges.
Figure 1 - 5 4
The two foot four folding ru le cou ld be used as a protractor using the values on table 1-1.
TABLE 1-1 ANGLES AND OPENINGS OiL Ang. Dis. Ang. Dis. in. 0 in. 0 in.
Ano, Dis. An g.
.21 3.34 .42 2 3.55 .63 3 3.75 .84 4 3.96 1.05 5 4.17 1.26 6 4.37 1.47 7 4.58 1.67 8 4.78 1.88 9 4.99 2.09 10 5.19 2.30 11 5.40 2.51 12 5.60 2.72 13 5.81 2.92 14 6.01 3.13 15 6.21
31 32 33
,
.
16 17 18 19 20 21 22 23
24 25 26 27 28 29 30
6.41 6.62 6.82 7.02 7.22 7.42 7.61 7.81 8.01 8.20 8.40 8.60 8.80 8.99 9.18
0
34
35 36 37 38
39 40 41 42 43 44 45
in.
0
9.38 9.57 9.76 9.95 10.14 10.33 10.52 10.71 10.90 11.08 11.27 11.45 11.64 11.82 12.00
46 47 48
49 50 51 52 53 54 55 56 57 58 59
60
Dis. in
Ang.
12.18 12.36 12.54 12.72 12.90 13.07 13.25 13.42 13.59 13.77 13.94 14.1 1 14.28 14.44 14.61
61 62 63 64 65
0
66 67 68
69 70 71 72 73 74 75
Dis. in. 14.78 14.94 15.11 15.27 15.43 15.59 15.75 15.90 16.06 16.21 16.37 16.52' 16.67 16.82 16.97
Ang. 0
76 77
76 79 80 81 82 83 84 85 86 87 88 89 90
1-2 MARKING TOOLS Marking tools are classified according to the kind of work it is to perform: 1. Chalk or charcoal line- is used for marking a very rough work. 2. Round pencil lead- used for mark ing rough work . 3. Scratch awl - is used in mark ing a sem i-rough work. 4. Scriber - is used in marking fine work. It is hardened steel with a sharp point designed to mark fine line. 5. Compass- is used to inscribe arcs or circle. 6. Divider - is used in dividing distances into equal parts' · particularly an arc or circumference.
5
SCRA"fCH AWL
r~--s-c_··-·-~~·· CHALK OR CHARCOAL LINE
COMPASS
Figure 1 -6
1-3 TESTING AND GUIDING TOOLS Good carpentry work demands accur~cy in measurement and a well fitted joint or parts together. This could be done with the various guiding tools for a precise and quality work. The different kinds of testing and
guiding tools are:
1. Level- is used for both guiding and testing the work to a vertical or ht>rizontal position. 2. Plastic Hose with water - is the best and accurate tool for guiding the work in establishing a horizontal level.
Figure.. 1-7 3. Plumb Bob - is used to check or obtain a vertical line. The word plumb means perpendicular to a horizontal plane.
6.
PL.UM8 808
Figure 1·8
4. Miter Box - is a device used as a guide of the hand saw in cutting object to form a miter joint.
Figure 1·9 5. Miter shooting board - is a plai n board with two 45° guide fastened on top of the upper board. This device is used for designing patterns, cabinets. etc.
'
Figure 1-10 · 7
6. Sliding r~bevel - is like a try square with a slidina and adjustable blade that could be set to any angle other than 90
SLIDING T- BEVEL
Figure 1·11
. ·TABLE 1·2 TABLE OF ANGLES Polygon No. of Sides
3
5 6 7 8 9
10
Angle
Tongue
Degrees
ln.
30 54 60 64.3 67.5 70 72
12
12 12 12 12 12 12
Blade em.
30.5 30.5 30.5 30.5 30.5 30.5 30.5
ln.
20718
8 25/32 6 15/16
5 25/32 4 31/32 43/8 3718
em.
53.0 22.3 17.6 14.6 12.6 11.1 9.8
Table 1 - 2 is useful in laying out the included angles of a given polygon.
7. Angle Divider- is a double bevel used to divide an angle a complicated work. This tool could divide an angle in one
8
/ /,.
...
[~
/
'
L-_J
SQUARE
COMBINED TRY AND ANGLE OlVlOER
MITER SQUARE
Figure 1-12
8. Square - is called a "Trying Square" . Square is a· right angle standard at 90 degrees us.ed in marking or testing work. The different types of square are: Try Square - is a square with blades that ranges from (3" to 15") 7.6 to 38 em. b) Miter Square - is a square w it h blades permanently set .
a)
at 45 degrees. c) Combined Try and Miter Square .- is a combination of 4 5 and 90 degrees in one set. d) Combination Square ..:.. is similar to a try square only that the head can be made to slide and clamp at any desired place of the blade and is also provided w ith a miter and a level gu ide. 9
e)
Framing or Steel Square - so called as it is used effectively on framing work.
FRAMING
OR
STEEL SQUARE
Figure l -13 Parts of a fram ing square:
Body- the longer and wider part Tongue- the shorter and the narrower part Face - the side visible when the square is held by the tongue in the right hand, the body pointing to the left. Back - the side ~isible when the square is held by the tongue with the left hand, the body pointing to the r ight. 10
. ,._ u:n HAND
TO NGUE.
Figure 1-14
TAf?LE 1-3 TABLE OF ANGLE FORM BY THE SQUARE (inches)
Angles: Tongue: Body:
2 3 4 5 6 7 8
9 10 11 12 13 14 15
.35 .70 1.05
1.40 1.74 2.09 2.44 2.78 3.13 3.47 3.82 4.16 4.50 4.84 5.18
20.00 19.99 19.97 19.95 19.92 19.89 19.85 19.81 19.75 19.70 19.63 19.56 19.49 19.41 19.32
Angle: Tongue: Body: Angle: Tongue:
16 17 18 19 20 21 22 23 24 25 26 27 28 29
30
5.51 5.85 6.18 6.51 6.84 7 .17 7 .49 7.80 8.13 8.45 8.77 9.08 9.39 9.70 10.00
19.23 19.13 19.02 18.91 18.79 18.69 18.54 18.40 18.27 18.13 17.98 17.82 17.66 17.49 17.32
31 32 33 34 35 36 37 38 39 40 41
42 43 44 45
10.28 10.60 10.89 11 .18 11.47 11.76 12.04 12.31 12.59 12.81 13.12 13.38 13.64 13.89 14.14
Body:
17.14 16.96 16.77
16.58 16.38 16.18 14.98 15.76 15.54 15.32 15.09 1<1.89 14.14 14.39 14.14
l1
1- 4 FASTENING TOOLS Fastening tools are the tools used to faster or secure parts of the construction that are to be connected together with nails, screws, bolts, etc. The different types of fastening tools are: 1. Claw hammer - a hand tool made of steel carefully forged, hardened and tempered. Its sizes varies from 140 to 560 grams. a. A 400- 450 grams is recommended for finishing work. b. A 450-560 grams is recommended for framing work. C •rv~
Nt<~
Figure 1·15
2. Wrenches- a hand tool with a handle and a jaw which may be fitted to the head of a nut used to tighten or loosen bolts. The three general classes of wrenches are: a. Plain b. Socket c. Adjustable
Figure 1-16 12
3. Screw driver- a hand tool with a head and a shank used for turning screw·, classified either as:
a.
Plai11 b. Automatjc ·
It may also be classified according to the shape of the tip of . the shank, such as:
a. Ordinary
b. Phillips
PLAIN SCAE 'W DRIVER
SCRt:'W DRIVER
YMH
Figurel-17 1- 5 ROUGH FACING TOOLS or STRIKING TOOLS Rough facing tools are the so called "Striking Tools" because they are used through a series of blows. They are also called "iner· tia tools", or "Rough facing tools" because the cut produced were rough. The differe'nt kinds of rough facing tools are: 1. Hatchet - is generally a1utility tool used for sharpening stakes and cutting down timber to rough sizes.
SI11HGLIHG
CLAW
Figure
BUREL
1-18 13
2.
Axe - a tool used for splitting wood or hew ing t i m~r.
Ol!tfFITH Ail-E
Figure 1·19
3. Adze- roughly, an adze is a hatchet in which the blade is at right angle with the handle.
$ .. If' A~lt Cllt &0 to Ut••
CAftP(W'ttft.'S ADZE. c ..t to lO 6&\4 1a em
Figure 1-20
1 ·6 TOOTHED CUTTING TOOLS In carpentry work, the toothed cutting tools is of utmost importance considering its versatility and service demand. There are several types of th is kind of tools: 1. Saws - T he most important of this k ind of tools are classified accord ing to: a)
Kind of cut:
1. Cross cut 2. Rip cut 3. Combined rip and cross cut 14
Figure 1-21 .b) Shape of the blades:
1. Straight back 2. Narrowed
3. Thin back 4. Skew back
STIIAieNT t•c;• Jtrl' s•w
THIN BACK f\tfl SAW
Figure 1-22
15
c)
according to its u,se:
6.
· 1. Cab inet 2. Joiner ·3. Miter 4. Stair 5. Floor
10. Hack
FLOOR
t
JOINER OR BENCH
MITER
Figure 1-23 16
Buck or wood
7. Compass 8. Key hole 9. Coping
B U"CI< OR WOOD
HAC I<
COPING SAW
COMPASS
Figure 1-24
17
2. Files - a metal tool of different shapes and sizes used for abrading, reducing or smooth cutting metal, wood or other materials. ·
HOM£NCI.ATUIU! Otr
SINGLE CUT
OOUIH.E CUT
rii.E
RASP
VUCEN
OtFft£1tl:ltT TYPE OF fiLES
•
•
CaOSS SECTtOit Of' flLU
Figure 1-25 18
0
1 - 7 SHARP-EDGED CUTTING TOOLS A- Chisel ....: is an indispensable tool in carpentry which is also considered as the most abused tool oftenly used for prying, can opener, open cases or as sc.r~w driver etc. Chisels are classified according to:
1. Service: a) Paring Chisel - a light duty tool used to plane · long surfaces parallel with the grain of wood. Paring chisel should not be driven by blows but only man ipulated by means of hand pressure. b) Firming Chisel - us~d for medium duty work usually ddven by hand pressure in paring or by the use of mal~et blow in mort ising work c) Framing Chisel - a heavy duty tool designed to absorb a severe strain in framing work where deep cut is necessary.
PAR i llO
'It AlliiN Gl
Clll$£ L
CHIS£ L
Figure 1-26
19
2. Lengt h : Butt
a)
~
kZ
g b)
~ :J pocket
~
kZ c)
M ill
CHI SEL ACCORDIN8 TO LENGTH
Figure 1-27 3. Side of Blade:
. b.
a. p!ain
BEVE L
Figure 1-28
20
~
Bevel
]
4.
Handle Attachment: a.
·Tang
b. Socket"
TAit
Figure 1-29 5.
Shape of Blade: a) Flat . b) Round (gouge)
c) L (corner)
•oue1 011 IIOUND
L ott COIIIIIR
Figure 1·30 Chisels may also be clas~ified accord ing to its blade with unnatural width. ' Those chisels with blades wider than (2 in.) 5 em is called "Slick" . .
B. Draw Knife- is used in trimming work by drawing towards the worker.
Figure 1·31
21
1 - 8 SMOOTH FACING TOOLS Smooth facing tools are sometimes regarded as "guided sharp edge cutting tools". These tools are actually chisels with frames to guide and lim it the cut and make it smooth. 'The different kinds of smooth facing tools are:
L Spoke Shave - a modified k ind of draw knife w ith an adjustable blade like a plane to limit the thickness of the cut.
SIN GLE- SCREW RAISED HANDLES
CHAIR MAK ER'S WOOOEII
$P0k£ SHAVE
,
,· -
'
. .'... 1
' DOUBLE SCIIEW HAIIO LES
CQNCAVE CUTTER
CHAIH Ell
Figure
' 22
CUTT ER
1~32
2. Plane -- is used in smoothing boards or other surfaces for framing and moulding. P~ane is also used to make wood surfaces into uniform thickness. Planes are classified according to its size and services:
1. Jack plane- for heavy rough work. 2. Fore plane- for smoothing and straightening the rough or irregular cut of the jack plane. 3. Trying plane-is used to obtain the smoothest finish. 4. Jointer--:- a trying plane is a simple small jointer. 5. Smooth plane- a small plane used for smoothing uneven surfaces in wood even those with minor depressions.
£ [ SYOOT M I' LAM£ .IIlJa . 30•.
FORt PLAII£ .411.,.
TIIYIMG PLANE
.511 to . 80111.
e '----===-:::=L_/-_~--,j/~-z_-----J, JOIIITER I'LAIIE .TOto .1'11!ft.
Figure 1·33
23
J.&.CK PL.AME
.•
SINGLE PI.AHit
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........
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-~,., '•' ~:;;_- '' ::--:: .;._ ·_-:.= ~
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TCiOTHI!D PLAIIIE
Figure 1·34 24
_~:...·
- .:.= ~
.
-:.
--.-··
~- ..,.:;:.:_'
-
6. Moulding and Special Planes - are planes used in making various shapes of mou lding and cuts. The different types of moulding planes are: a) Rabbet or Rebate Plane - used for making a sinking
cut on wood to make them fit t o each other. b) Fillester Plane - similar in use as the rabbet plane but is more preferable because it cuts more accurately than the former. c) Groov ing Plane - used in cutting across the wood grain. d) Router - used to surface the bottom of the grooves. e) Round and hollow moulding plane- used to produc e a concave or convex surface.
IIA18E T
CO VI!
QUAil T !R ROUMO
MOULDINC.
ANO SPECIAL I"LANf
Figure 1-35
25
1 - 9 BORING OR DRILLING TOOLS These tools are special ly designed to mak e hole in wood. The different types of dr iII ing t-ools are:
1. Brad awls- A small tool used for punching or piercing sma ll holes. It is generally used in starting a nail or screw into hardwood. •
Figure 1·36
2. Gimlets - Tool s used for boring small holes by hand pressure classified as: a) Twist
b) Plain
TWIIt
I' LAI M
IIIII Lf.TI
Figure 1-37
3. Augers- is used for boring holes with a diameter from liz" to 2" inches or 12.7 mm to 25 mm. Augers that are pro· vided with a shank are commonly called "bits" 26
~oMeLI
Tli£Ao·
SlUt I
CUTTU
DOUet I CIIHlll
~"'" If£ AD 1\NGLt CUTTER
$1111' HEAD
OOUILI! TREAt>
Sln<.E CI.ITTEII No er
If•
Kt•"
(a) Single cutter. extension lip, coarse screw, for general all around boring; rap id, dean cutting tnd ..sy boring adopted in boring wet, green, hard or knotty wood and boring with the grain. (b} Double cutter, extension lip, fine screw, npcommended for fur· nltures and cabiMt work or wherever a smooth hole is essential. (t) Ship h..d with single cutter and coarse screw, Absence of lip is recommended for deep boring or in wood with strong grain. (d) Ship hNd single cutter without screw or lip is recommended for deep borln9 In wet pitchy woods. The absence of strew has less ten~ncy follow or drift with the .!I~~ in of the wood.
to
Figure 1·38
4. Twist Drills- used for drilling small holes. Twist drills are preferably used in cases where the gimlets or the auger may cause splitting of the wood grain. These tools has lesser tendency to split the wood grain because they are not provided with a cutting lip.
l)II.ILL
e•~aST
DA tL~
Figure 1-39
27
5. Hollow Augers- "!sed for external boring or turning.
~=s~-,. - --1;zr----,1
c
,,un~r.
AUU. I
liT
Figure 1-40
6·. Spoke Pointers - cuts conical holes. It is similar to the auger only that the cutter is lengthwise. 7. Counter ~inks - used for enlarging a conical hole at the surface of wood. 8. Reamers- usually a reamer is used chiefly by machinist in enlarging metal holes. It is also used in carpentry work for enlarging holes on wood when made too small for the screw or its head.
OCTAIOUI. TYPl jt«A*II
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...
--
.
·-
1'0111 ,OIPITU
4
sc••• *"''
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Figure 1·41 These tools are u5ually provided with a sha.n k instead of a handle, hence, a brace is indispensable. 28
PLAIN liT IIUef.
Figure 1-42
1-10
HOLDING TOOLS .. .
Hold ing tools is vital and important in accompl ishing f ine carpentry work. In many stages of construction the need for holding the materials in place rigidly is necessary. Holding tools may be classif ied accord ing to its 5erv ice: ·
1. Supporting - Carpentry wor.k such as chiselling planing and the like, needs support to amply sustain the operation. The Hor5e or Trestle is the r ight tool for the purpose.
Figure 1·43 2. Retaining- Under this category, there are several kinds of holding tools considered as rigid and strong enough in tightly pressing the materials together.
29
a) Clamps - is effective in tightly pressing pieces of wood together in making tenon, mortise and other joints. Clamps may be classi fied into: 4. Miter
1. Single Screw Jaw 2. Double Screw 3. Chain
5. Beam A .
~,"·.. .r ·
''.·., ..
·,
''t
,
'·. // .
/,·"'>
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MITAI! CLAMP
r~ I
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.
t~
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.
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OHP TllAOAT C- CLA MP
SO UAit[
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IAR
~
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C-
C L AIIIP
C LAN,
Figure 1-44 b) Vises - A tool used t o hold a piece of m aterial rigidly secured in place to absorb severe blows. The available types of vises are:
1. Screw 3. Parallel Jaw 2. Quick acting screw 4. Swivel Bottom 5. Self-adjusting jaw 30 .
Vllt:S
Figure 1-45
1-11
SHARPENING TOOLS
Experienced carpenters realize the importance .of sharpening tools in carpentry operat ion. Sharp tools assure the worker in accomplishing a quality work and is faster than using dull tools. The different kinds of sharpening tools are:
1. Grind Stone - a flat disc solid stone usually of sandstone mounted on a shaft used f.or sharpening, shaping or polish ing metal by turning. · 2. Oil Stone- Used after the grinding operation to achieve a sm.ooth and keen edge of the tools. Oil is used as a lubricafing medium and that is why they are called oil stone. Oil stone are of two types: a. Natural - found in their natural state b. Artificial -are ordinary abrasives such as carburandum alundum and emery.
Figure 1-4:~ • .•
31
1-12
WORK BENCH
Work bench is also an important tool in carpentry operation considering the var'ious tools attached to it. Work bench is considered as a shop tool and is needed for the different kinds of onsite or off-site preparation of wood parts in all construction projects. .·:,;·-.;..
Figure 1-47
B - MASONRY TOOLS Masonry. is the art of shaping, forming, arranging, laying and uniting stone, bricks, building blocks, plastering etc. to form walls and other parts of the building. Masonry tools are so designed to accompl ish many types of masonry work. Masonry tools also include some of the carpentry tools previously mentioned particularly the measuring tools, the testing and guiding tools. Masons also use other kinds of special tools aside from . the previously enumerated tools adopted to the kind of work involved ..
32
1-13
ROUGHING UP TOOLS
Roughing up is the process of preparing the surface and parts of masonry work. It involves the rough work of dressing, and pre· paration of the different phases of masonry work. Tools for this type are mostly striking tools and those that also need a striking medium. 1. Mason's Axe or Hammtr- Is also known as Ax-Hammer used in two different ways. The axe to serve as a chisel and the hammer for driving nails and other rough work in masonry. 2. Brick Hammer- 1$ another type of combination hammer wh ich is used for dressing and cutting bricks, stone or concrete and other driving operations. 3. Patent Hammer - Is a hammer wherein the head is composed of a group ofth in chisels used for dressing stone or concrete. 4. Crandall- A tool w ith sharp pointed steel spikes used for dressing stone or concrete. 5. Cross Peen Hammer- Is a cross head hammer where one is shaped I ike a wedge used for various striking need in masonry work. 6. Cold Chisel- Is a common tool for carpentry, and masonry work used for dressing or cutting stone, concrete, metal and other materials with the aid of hammer. 7. Star Drill - Used for boring or drilling holes on hard surface such as rock, stone or concrete. 8. Bolster- A tool similar in appearance with the cold chisel including its services but has a wide blade edge. It is· also known as blocking chisel. 9. Wrecking Bar - a very useful tool made of steel bar used in demolition work and in pulling- off large nails.
STEEL MALLEl B~ I C I<
HAMME R
CRA N DALL
HATCHET
COLD CHISEL
STAR
DRILL
CROSS PEEN
MASONS
HAMMER
SHOVEL
Figure 1-48
HAMMER
1-14
SUAFACE FINISHING TOOLS
Tools of this classification are categorized 'into: 1. Floats- flat tools with a handle at the back usually made of wood. Kinds of float: a. Common float- used for smoothing or for producing textured surfaces on cement or plaster. · b. Bull float - a tool used to smooth freshly placed · concrete. c. Devil or Nail float- a tool.used to roughen the surface· of plaster to provide a key for the next coat. d. Carpet float - used in plastering to produce a fine- · grained texture in sand finishes. e. Angle float- used for finishing corners and for pfaster:. ing.
b
'~-------------------*
Figure l-49. 35
2. Trowels- flat hand tools used for applying, spreading and · shaping plaster or mortar to produce a relatively smooth finish on concrete surfaces in the final stages of finishing. The kind of trowels are : a. Ordinary trowel- similar in appearance as the ordinary float but with a steel blade. b. Pointing trowel - a trowel used in pointing or remov· lng and laying mortar In masonry joints. . c. Brick trowel - a trowel with an offset blade used to pick up or spl'ead mortar. d. Buttering trowel - a small trowel used to spread mortar on bricks and tiles before it is laid. e. Edger a finishing trowel used on the edges offresh ~::oncrete or plaster to form a rounded corner. f. Margin trowel - its sides has a box-l ike appearance especially used for working corner angles.
MARGIN
POIN'fiN8 TROWEL
TIIOWlL
FINISHING
aUT TEtiUIC$
36
TROWEL
1 -15
MISCELLANEOUS MASONRY TOOLS
There is so much duplicity in the functions of masonry tools. There are also tools which can easily be fabricated by a prolific mason. Tools of this kind are those simple tools but are considered worthy of notice since they accomplish an important task in making the rigorous work involved in masonry simpler.
1. Spade - a basic construction tool used in many of the dirty work in the concrete mix or plaster. 2. G. I. pail- in the absence of a chute or a buggy, it is used as vessel in handling especially lntransferringconcrete mix, mortar or plaster from the mixing board.
3. Mixing board- usually made of wood or concrete used for mixing' concrete in the absence of a concrete mixer. This is usually fabricated on-site. . .. 4. Mason's box - a shallow box, made of wood, used to contain mortar or plaster to make it easily accessible to the mason. 5. Measuring box - a box, made of board or plywood with handle, used for measuring sand, gravel etc. prior to mixing. This tool is also fabricated. 6. Rubber foam - used to obtain a fine-grained texture in plastering. 7. Painter's brush - its use in masonry work is similar to the foam.
8. Plastic or nylon string- used for marking and guiding the block laying, tile laying. etc. to produce a uniform and straight course. 9. Aligning stick - various names can be attributed to this tool which is simply a straight piece of lumber, more or less L50 m. long used in plastering and concreting the pavement to assure alignment or a straight surface. . · 37
C. PLUMBING TOOLS
~~·' .
m ,,:.
~~~i.;i'-'---'r ~
"\... '
:
..
.
.
··--··- ····· P IP €
CUTTER
S TIL LSON WRENCH
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Figur e 1 - !> ll
38
VIII£
D. PAINTERS TOOLS
-uti ns
,
NAIL SET
WALL
PUTTY
SCRAPER
KNif'E
HOOK SCRAPER
PUTTY
PLATE
CUTTINO ·IN ROLLER CORNER ROLLER
TRIM ROLLER
E OG1NG ROLLER
PAINT SPRAYER
__ --
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r
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f
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- . .......
~ .' ~ ,: , ; r!., It
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Figure 1 52
39
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E. ELECTRICAL TOOLS
(O)
l
l/>) Small hand
bend•~
Simpl< bcod fo
maohont.
Pipe·bPnding muchines.
Figure 1-53 .40
F.. TINSMITHING TOOLS
C>IANNf.L ·LOCK PLII!II$
SOLO£fUK8 ROO
IUI/£T(II tOT10111
Figure
OIOLO!~
'
1-54 .1,
CHAPTER
2
WOOD 2.- 1 INTRODUCTIOI\.I Wood is that fibrous substances which compose the trunk and branches of the tree that lies between the pith and the bark. Wood is the most common of the building materials. The versatility of using wood in the constru ction has lifted it to its present importance in the field of construction. Small houses and even palatial homes used wood from its structure down to the finishing and articulate carvings. Even with the introduction and acceptance of new methods and materials in construction, wood is evidently much in use. Concrete buildings used wood from the very start of its erection. Likewise, steel c.onstruction also use wood. Wood because of its strength, light in weight, durability and ease of fastening has become one of the most important bu ild ing materials. Many Scientists and Engineers are engaged in the study and research for the development of new methods of full utilization of wood. New processes are being developed to reduce if not to el iminate waste in the manufacturing of wood .
2-2 DEFrNITION OF TERMS:
1. Lumber = Is the term appl ied to wood after it is sawed or sliced into boards, planks, timber etc.
2. Rough Lumber dressed lumber.
=
Is the term applied to unplaned or un-
3. Surfaced o_r Dressed Lumber = Is a planed lumber having at least one smooth side.
4. S2s; S4s ~ Are planed or dressed lumber of which the number connotes the number of smooth sides; such as S2s is · smooth on two sides. 5. Slab = Is a kind of rough lumber which is cut tangent to the annual rings, running the full length ofthe fog and containing· at feast one flat surface.
- - - - - --·-·· - - -
42
6. Timber = Is a piece of lumber five inches or 13 em. or larger in its smallest dimension. 7. Plank= Is a wide piece of lumber from 4 to 13 em. thick.
8. Board = Is a piece of lumber less than Hz" or 4 em. thick and at least 4 inches or 10 em. wide. 9. Flitch= Is a thick piece of lumber. 10. Fine Grained= When the annual rings are small, the grain or marking which separates adjacent rings is said to be fine grained; when large, it is called Coarse Grained.
11. Straight Grained = When the direction of the fibers are nearly parallel with the sides and edges of the board, it is said to be straight grained. When the lumber is taken from a crooked tree, it is said to be crooked or cross·grained. 2-3 CLASSIFICATION OF WOOD: Wood used in building construction are those wood which grow larger by addition of layer on the outer surface each year known to botanist as OXOGENS. Wood are classified according to:
1. Mode of Growth:
a. Exogeneous = Are those outward growing trees which are most preferred for lumbering. b. Endogeneous = Are those inside growing trees and are not preferred for lumbering because they produced a soft center core.
2. Density= Density is either: a. Soft b. Hard 3. Leaves : The leaves of a tree is either: a. Needle shape {conifers) b. Broad shape
43
4. Shade or Color: a. White b. Yellow
c. Red d. Brown
e. Black, etc. 5. Grain:
a. Straight b. Cross c. Fine d. Coarse 6. Nature of the surface when sawed:
a. Plain b. Grained c. Figured or marked
CROOKED GRAIN
.,:···;·
CROSS Ga.Anf
STRAIGHr GRAIN
Cross Section of a Tree Figure 2-1
2-4 PREPARATION OF WOOD Lumbering is the term applied to the operations performed in preparing wood for commercial purposes. It involves logging which is the process or operation of felling or cutting of trees including ib hauling and delivery to the sawmill for sawing. Sawing on the otherhand, is the operation of preparing or cutting the logs into its.commercial sizes.
The methods and manner of log ~wing are: 1. Plain or 811Stard Sawing: Is the cutting of the logs entire!. through the diameter and parallel chords tangential to the annuc rings. 2. Quarter or Rift Sawing
a. Radial b. Tangential
c. Quarter Tangential d. Combined Radial and Tangential
COMa!He!P 1\.\0\M. ~ TlMUtl'ftA\.
Figure 2·2
2-5 DEFECTS IN WOOD Defects· are irregularities found in wood. The most common defects in wood are:
1. Caused by Abnormal Growth a. Heart Shakes = Are radial cracks originating at the heart of the logs.
45
b. Wind Shakes or Cup Shakes = Are cracks or breaks across the annual rings of timber during its growth caused by excessive bending of the t ree due to wind. c. Star Shakes = Composed of several heart shakes w-hich radiate from the center of the log in a star-like manner. d. Knots = Occurs at the starting point of a limb or branch of the wood.
2. Due to Deterioration: a.
Dry Rot = Is the presence of moisture caused by fungi in seasoned wood. b. Wet Rot = Takes place sometimes in the growth of the tree caused by water saturation.
Figure 2-3
2 - 6 SEASONING OF LUMBER Trees when fallen contains moistu re in their cell layer. These moisture should be expelled thoroughly to preserve the .lumber from shrinkage or decay. Experiments have proven that timber 'im· mersed in water immediately after being fallen and squared is less subject to splitting and decay. It reduces warping but'makes the wood brittle and less elastic. Soaking timber into liquid is the ' method of seasoning practiced by the ancient Roman builders. Sometimes wood are steeped in oil of cedar t o protect it from worm attack.
... Salt water makes wood harder, heavier and durable. However. wood intended for use in buildings has the tendency to attract moisture from the air. The Two methods adopted in seasoning of lumber are:
as
1. Natural or Air Seasoning= This is considered one of the best method of seasoning lumber although the period involved is relatively longer. The processes are: Lumber is piled outside where its length 'are sloped at about 10 em. to the meter height. · b. Lumber is piled in a well.ventilated shed. Each piece is properly and evenly spaced from each other for free circulation of air around the lumber. , a.
2. Artificial Seasoning = The lumber is stacked in a drying kiln and then exposed to steam and hot air. Artifidal seasor.ing i.:; resorted for quick drying but wood from this process is quite inferior than that seasoned by the natural method. The different artificial seasoning methods employed are: · Forced Air Drying = Fans are 'used to booster the cir· culation of air preparatory process to kiln drying. b. Kiln Drying= Lumber is dried in a specially built room or chamber by which temperature and humidity as well as the circulation of air is controlled. c. Radio Frequency Dmlectric Drying = A very fast method of drying lumber wherein the use of radio fre· quency dielectric heat is employed. Drying through this process may only take 24 hours as compared to the other methods. a.
2 - 7 · CAUSES OF DECAY AND METHODS OF PRESERVATION Wood does not decay naturally through age, nor will it decay if it is kept constantly dry or continuously submerged in water. The common causes of decay in wood are:
1. Altern.:~te moisture. and dryness 2. Fungi and molds 3. Insects and worms 4. Heat and confined air 47
The essential requirement to achieve a successful preservation of wood is good seasoning and the process of preserving wood are:
1. External = The wood is coated with a preservative coating (as paint) which will penetrate the fibers. 2. Internal = A chemical compound is impregnated at a pressure to permeate the wood thoroughly. The different processes are: a.
By impregnating the timber with a 2 percent zinc chloride solution followed by an injection of about 45 kg of creosote oil per cubic meter of wood.
b. The cylindrical tank is filled from the charging tank with creosote oil at a temperature of 930 C and pres· sure is applied until the timber absorb oil to a pre· determined amount. c.
A partially seasoned timber is run into the metal cylinder 2.50 to 3.00 m. diameter by 50 meters long and the doors or heads bolted. A pressure of 1.5 kg per sq. em. steam is applied in 30 minutes and maintained from 1 to 5 hours. A vacuum of 60 centimeters is created and maintain for 11/z hour when creosote oil is introduced at a temperature of about 70° C. A pressure of about 12 to 14 kg. per cm2 is then applied until the timber has absorbed 50 kg. of oil per cubic meter.
d. Another method is by emersing timber into 2 ·solution of corrosive sublimate, 1 part of bichloride mercury to 99 parts of water for a period of 5 to 10 days sufficient enough to insure thorough penetration o.f the preserva· tive. The sublimate is insoluble in water/ and remains in timber for a longer time than salts like zinc chloride. The external non·pressure process of preserving wood is the application of a penetrating nature as tar oils, carbolineum, spirittine, solignum, etc. It may be applied on the surface of wood either by brush, spray or by immersion. External preservatives could only be effective if the wood to be treated is absolutely dry and · well seasoned in order to absorb a sufficient quantity of the pre· servative. All tar oil products should preferably be applied hot.
48
2-8 MEASURING WOOD Although the System International (SI) has already superseded the Engl1sh System of measure, the board foot as the unit measure of lumber popularly and widely used is still presented for reference in preparation for the transition from English to Metric approach. A board foot is actually one square foot of wood one inch thick. The formu la being used in com·puting board foot is:
txw xL 12
Board Foot = -....;._...:..:.........;.;..-...:..;_...=._ Where t =thickness in inches w =width in inches L = Length in feet This formula is being used for sawed wood of commercial dimensions. Example: Compute the board foot of the following lumber : 5 pes- 2"x6"xl4' Bd. ft.
= 5 X 2 X 6 X 14' 12 ==
70
Note* Under the English measure of lumber, the length is always ordered at even· length. The above formula could not beusedin finding the board foot of.logs. Instead, the following formula is applied:
Board ft.
{0 - 4)2x L
=---.:.-..-16
Where 0 = smaller diameter of the logs in inches L"" Length of iog in feet 4 and 16 = are slab deduction allowance which are constant in the formula
.49..
1-.
t8'
Figure 2·4 ·Illustration: From the above figure, find the total board foot that coul(j be derived from the log for commercial purposes. Solution: Board Ft. -
{24 - 4)2 X 18ft. 16 2 (20) X 18 16
= 450 bd. ft~ Sometimes lumber is computed by the linear foot method, A PPl ied to lumbe.r hav ing a width and thickness of 2 inches or less. The linear foot-method is simply mu.ltiplying its length in teet by the unit price. To convert linear foot to board foot
Linear foot of lumber size. 1 X 2" - - · - - - 2x2 - - - - - -
50
divide length by
6 3
to get
- - - bd. ft. bd. ft.
2-9 ENGLISH TO METRIC MEASURE OF WOOD Lumber is customarily computed in terms of board foot which simply means that one board foot is equivalent to 1 inch thick,· one foot wide and one foot long wood. To find a board foot of a piece of wood say 2'' x 6'' x 20' the thickness is multiplied by the width and length divided by 12 thus:?. x 6 x 20'= 20 bd. ft. ·
12 Following such principle where one inch is the unit measure in
a foot, one centimeter is also the unit measure in a meter, the above piece of lumber could be written as .5 x 15 x 6 m "' 4.5 board meter 100 where: 2""" 5 em; 6" = 15 em 20' =6 meters From this example, we could then say that a board foot multiplied by .225 is converted to a Board Meter. Thus, 20 x .225 = 4.5 Bd. m. Most probably, the length of lumber under the Sl measure will be at the intervals of .50 m phasing out the even length of lumber in feet. Example: 2" x 4" x 16' will be ordered 5 em x 10 em x 5 m.
2,-,10
MANUFACTURED BOARDS
Manufactured boards are made of wood but does not appear in their natural state. This type of building materials can be classified as a type of lumber as they are the by-product in the manufacture of lumber. The complete utilization of wood has led to an expanded field of manufactured boards. ·There are different types of manufactured boards available such as:
1. Plywood = is made of an odd number of veneer sheets glued together with the grains ruMing at right angle toeach other. Forest laboratory test show that plywood shrinks less tnan Itt of 1% in drying from saturation to 6% moisture content which is less than the shrinkage of solid wood of the same species under similar conditions. 51
Plywood is light in weight and strong that screw or nail can be driven dose to the edges without danger of splitting. Plywood thickness varies from (1/8") 3.2 mm; 4. 7 mm {3/16"); 12.7 mm (lk..} to 25 mm. available in 3 to 5 ply panels. The different types of plywood are:
1. Soft Plywood = The most common for structural use. 2. Hardwood Plywood =Are used for panelling and finishing where usually only one face is hard finished. 3. Exterior or Marine Plywood = Is made for external use, sometimes used for construction of boats.
FoV£ ·Pl"t C~ti!IICTIOH
OIWIT.. 8ANGII!Nl OIIIU'LIIIO
Typical plywood construction Figure 2~5 2. Hardboard = Hardboard or pressed wood is made from wood chips which are exploded into fibers under steam of high pressure.The lining in the wood itself binds pressed wood together with no fillers or artificial adhesives ap· plied. Pressed wood is equally strong in all directions but very brittle. Its color varies from I ight to dark brown. 3. Particle Board: Is manufactured from wood chips, curls, fibers, flakes. strands, shaving. slivers, strands etc.• bound together and pressed into sheets and other molded shapes. , Particle board has equal strength in alt directions of a given cross sectional area, it is not brittle and can resist warping.
52
CHAPTER
3
LAYOUT AND EXCAVATIONS 3-1 DEFINITION Layout is sometimes 01lled "Staking out" which means the process of relocating the point of boundaries and property line of the site where the building is to be constructed. It includes clearing, staking, batter boards and establish ing the exact location of the building foundation and wall line on the ground. For short others define layout as the process of transferring the building plan measurements to the 9round of the site. Stake - are wooden sticks used as posts sharpened at one end - driven int o the ground to serve as boundaries or support of t he batter boa rds. Batter board - wood stick or board nailed horizontally at the stake which serves as the horizontal plane where the reference point of bu ild ing measurements are established. String - is either plastic chord or ga lvan ized wire across the batter board used to indicate the outline of the building wall and foundation.
3.. 2 LAYOUT METH.OOS AND PROCEDURES Step 1. Before the construction begins see to it that a Building Permit is first secured from the locaJ authorities concerned. Constructing a building without the necessary permit is considered as malpractice and contrary to • existing laws punishable by f ine or jmprisonment or both upon the discretion of the court. The amount that you are supposed to sav.e from not paying the necessary building permit fees Is comparatively less than the expenses you will incur in seeking remedy to your problem.
Step 2.. Relocate the ·boundaries of the construction site. It is suggested that lhe relocation of the property line shall be done by a Geodetic Engineer specially for those. lots without existing reference points or adjoining structures. There were numerous cases filed in court for·encroachment to adjoining property which · all started f rom layouting and excavation without property relocation by a competent surveyor.
53
Step 3. Clear the site of any existi ng structures, trees ana other elements that will obstruct the construction work. Cutting of trees shall be limited only to those that will hinder the progress of the work but don't forget to consult the local forestry authority . before the cutting to avoid further jusHfication, penalty or imprisonment.
GOMSaiiCT IOII
lAYOUT
Figure 3 -1 Step 4. Construct and allocate a space for laborers' quarters, construction office, bodega for the materials and working tools and temporary waste disposal. These requirements could be possible if the construction site is' big enough to allocate · space for such a purpose. On the contrary, if the site is l imited to t he area occupied by the structure, an off-site preparation, storaging and batching of conc;:rete is inevitable. Step 5. Apply for a temporary connections of electric and water supply. Electric current is important for the power needs of the tools and equipment and is necessary on overtime schedules especially in the time of concreting. Water is also a prim& need in· the construction, should there be no source of water along the vi cinity of the project, undeground water pump is the alternative. 54
Step 6. Construct a temporary fence around the construction. The fence will protect the materials from pilferage both from out· side and inside. Step 7. Order the construction materials that are sufficient for the working force to accomplish in a week period. Insufficient supply of construction materials increases the overhead cost. StepS. Verify the ·measurement in the plan if the distances ind icated are from: 1. Center to center 2. Center to outer 3. Outer to outer 4. Inside to inside these methods of indicating distances on the plan are commonly overlooked by the foreman, hence, should be given attent ion before the layout work.-
OUTEI! TO CENTER
OUTSIOI!:
lt4SIOE
Figure 3-2
Step 9. Fix the batter board to its horizontal position with the aid of a level instrument preferably plastic hose with.water. Usually, the batter board is aligned with the ground floor elevation. The important points in the plan such as post distances and wall cor- . ners are indicated on the batter board by common wire nails wherein the string is tied and laid across the opposite direction of the batter board. Most if not all building plans are parallel with the fronting street, the setback of the building from the road is first verified from the plan and is marked as the reference line where to start the measurement. Establish the.corner to 900 angle with the aid of plywood or stick made to a right triangle. The use of transit instrument is preferred for a large construction but is seldom used on small and medium projects. The use of small square in layouting is not advisable because it will always result to big errors. 55
Figure 3 - 3
Step 10. ·Verify the measurement on the batt~r board. Some· times the number 110 on the zig-zag rule is mistakably read as 100 by the measuring carpenter in the process of indicating the distances of post or column. The position of the stake should be wellplanned ·not to be affected by the excavation, otherwise, future adjustment and correction of the batter board might displace the right position of the reference points. · Step 11. · After establishing the reference point and line of t he footing, transfer the intersecting points of the string on the ground by the aid of plumb bob and indicate the size and width to be excavated.
EXCAVATION Excavation work in building construction is categor ized into two types: the minor, and major excavation depending upon the size .and nature of the foundation to be constructed. Excavation for a small construction with independent wall. or combined footing is classified under the minor excavation, while the rest which requires sizable or total extraction of the earth fall under the category of major construction.
'56
3-3
MINOR EXCAVATION
ExcavatiOI:'IS under this category are those constructions having independent footing and hollow block wall footing where the dig· ging of the soil for the footing extend to a depth from 1.00 to l.SO meter and about half a meter depth for the wall footing. Constructions involving minor excavations are common and occupy the biggest percentage of works accomplished in the· field of construction. Under this type of work, excavation is considered as minor because it does not involve the difficulties· of sheeting, bracing or underpinning except on rare cases where underground soil are too· fluid or loose that small vibration creates erosion that cause damage to the construction activities. It is a common concept that excavation is simple as digging the soil after the final marking of the building out Iine has been established on the ground. Unfortunately, there are factors that should be considered in the process which when overlooked might result to waste of materials and labor in the process of correcting and adjusting the work. The topographical condition of the ground plays an important role in excavation work. For instance, when the· ground is level or flat , laying out and excavation are simple and easy because the problem of whate:ver depth is required could be readily verified from the top of the ground so that a uniform depth could be ascertained. Consequently, the succeeding work such as setting the reinforcements, forms and concreting followed by the block laying will meet no problem of adjustment and correction. When the site is sloped' or a rolling ground, there are problems that are most likely to arise:
1. What depth shall be excavated for each of the different footings? 2. How deep shall the excavation be for the wall footing and where shall the excavation depth be based? It has been observed that most of. the building plans submitted applying for a building permit shows a uniform height of footing, . regardless ' of ·the ·topographical condition of the site, much more of the footing detail that heights of the footing to the floor line is · measured not by the number of value but by word "verify". This is an absolute manifestation of the planner's neglect either through omission or commission of not obtaining the accurate and ·complete information of the site condition before finalizing-the plan. ·
51
To handle the problems of excavation on sloped or rolling ground, the following methods are presented:
1. For grounds with a minor slope condition, it is advis· able to base the depth of the excavation from the horizontal level of the batter board which is usually extended by the layout string.
IIATTU tOAAO E•€VI'T10" AS Rt:H.R£NC£ LIME f'OR EXCAVAYION
Figure 3 -4 2. The excavation depth of the wall footing from the batter board elevation Is equal to the cumulative· sum of the footing thickness plus the height o! hollow blocks and the mortar.
is .~
Ct:I'TM Of U<:olV.TIOM lli!PTII
or UCAVATION
&A$£0 'RO.. TN£
COM .. ULATIV£ NltOIIT 00 FOOTING1
loiOtn'AR AIIO Ck8
Figure 3-5 3. Another method is the use of stepped or sloped wall footing where excavation follows gradually with the slope of the ground. It is more economical to make adjustment in the excavation of the ground than adjusting on the block laying using masonry block or concrete mortar which are very ex· pensive.
58
I J
l l I
I
I
l I
I I
I
I
I I
I
I
I I
I
STEPPED FOOTING
SLOPED fOOTING
Figure 3-6
3 -4
MAJOR EXCAVAT ION
Building construction that requires wide excavation or total extraction of the soil are classified into two categories depending upon the condition or location of the site. Wh~n the area of the construction site is big that there is enough space to accomodate working activities, storaging of materials and dumping ground for the excavated soil, problem is less due to the free movement of construction equipment. Under this condition, the necessity of providing lateral support to the excavation ground 'such as sheeting, bracing or underpinn ing is not necessary since there is no adjoini ng proper ty to be protected from damage that may be caused by· digging, pile driving and other factors that may contribute to the settlement of the existing structure. The constru'ction progress could be seen immediately .due to the accessibility of the construction materials, site fabrication of building parts and the disposal of excavated soil within the premises which minimizes overhead expenses of haul ing, rental and maint enance of heavy e.qu ipment. Bu ilding construction on a b.usy commerc ial center with adjacent existing structure is considered to be the most complicated among t he various construction works since this requires· careful study and analysis of the right approach. Under this condition, professionals and experienced bu ilders have also encountered t he following problems: · 1. The manner of excavation to be employed which will not affect or damage the adjoining 'structure. 59
2. The kind of equipment to be used in digging and extracting the ground may not be a problem but the place where to station the equipment during the operation. Manual digging Is very costly and time consuming, but sometimes could not be avoided if the situation does not warrant the use of power equipment. 3. How and where to dispose the extracted soil involves the effective manner of maneuvering the payloader and dump: . trucks in hau ling without obstructing the pedestrian and vehicular traffic flow. 4. Where to dispose the underground water to be drained by the water pump during the process of construction which might cause muddy road and create inconvenience to traffic. 5. The kind of sheeting and bracing to be used in shoring or under.pinning to protect the adjoining structure must be considered~
·Comments Shallow excavation can be done even w ithout supporting the encloSure if there is enough space to establish a lower slope wh ich the excavated earth could stand. The steepness of the stope de· pends upon the character of the soil, climate and weather con· dition and the duration of time the excavation will remain open. Excavation that are extended below -the wa~_e_r .!~ble usually demand drainage.of the;site priortoorduring the construction work Erosion or sliding of the excavated soR is a problem not only during the excavation stage but even during the installation of steel bars and forms. The cost of removing· the materials affected by the slide plus the additional excavation to provide a flat area contributes largely to the cost aside from the delay of the work: These problems should be anticipated and that necessary preventive measures should be made to prevent undue erosion. Sheeting and bracing are solutions.
the
The Building .Code on the protection of adjo ining property provides: "Any person making or causing excavation to be made below existing grade shall protect the excavation so that the soil of adjoining property will not cave-in or settle and shall defray the cost of underpinning or extending the foundation of buildings on adjoining properties. ·Before commencing the excavation, the person making or causing the excavation to be made shall notify in writing the owner of the adjoining build~ ings not less than · 10 days before such excavation is to be made and that the adjoining buflding will be protected by him. The owners of the adjoining properties shall be given access to the excavation for the purpose of verifying if their pl'operties are sufficiently protected by the person making the excavation. Likewise, the person causing such excavation shall be given access to enter the adjoining property for the purpose of physical examination of su<::h property. prior to the commencement and at reasonable periods during the progress of excavation. If the necessary consent is not accorded to the person making the excavation, then it shall be the duty of the person refusing such perm ission to protect his 'building or structure, The person causing the excavation shall not be responsible for damages on account of such refusal by the adjoining owner to permit access for inSpection. In case there is party wall along a lotline of the premises where an excavation is being made, the person causing the excavation to be made shall at his own expense, preserve such party wall in a safe condition as it was before the· excavation was made and shall when necessary, underpin and support the same by adequate methods."· ·
a
3 - 5 SHEETING AND BRACING SHALLOW EXCAVATION There are some legal cases filed in Court demanding damages due to settlement of existing structure brought about by excavation of adjoining property. Excavation involves the removal and . disturbance of materials that consequently create changes in the present concHtion of the soil or rock, such distu rbances occur 61
even if the sides of the cut is supported or not by sheeting and bracing. Changes in stress is always associated with deformation in the same manner as excavation is always accompanied by movements which contribute to the tendency of settlement which could be minimized by the proper application of sheeting and bracing enumerated as follows: 1. The lateral pressure in the material adjacent to the excavation could be reduced materially by means of a. proper design and careful placement of sheeting and bracing, if the excavation will not extend beyond the depth of 3.50 meters. The common practice is to drive vertical planks called sheeting around the property line of the proposed excavation. 2. The sheeting and bracing should be strong enough and capable of resisting latera l pressure . 3. The depth of the sheeting shal l be maintained below the bottom of the hole as the excavation progresses. Previous failure is due to u nstrict observance of the proper sequence of excavation and b~acing when excavation are permitted to advance too far before the installation of the next set of support. 4. The sheeting shall be supported by horizontal beam called wales supported by horizontal struts extending from side to side of the excavation, if the excavation is too wide for the struts. to be ex1ended ~cross the entire width, the wales shall be supported by inc I ined struts called rakes or rakers.
WGie
llertico I wood . t'lleetlnq Slrul
- Vet lleol wood
BRACING SID£$ 01' SHALLOW £XCAVATt0tiS··
Figure 3 -7
62
5. There should b~ a close observation, frequent measure· ments and recording of the·verticat and lateral movement and be· haviour of the sheeting and bracing to provide early warning of unfavorable development which might cauSe settl.ement of the adjacen~ property or structure. . 6. If the work is under contract, a rigorous provisions regard· ing the sheeting, bracing and excavation shall be incorporated in the agreement to be strictly enforced during the execution of the work. 7. The most effective way of prevent ing lateral movement of the soil rs oy prestressing the bracing or struts.
Figure 3
-a
3 -6 SHEETING AND BRACING OF DEEP EXCAVATION The methods of sheeting and bracing a deep excavation to be discussed under this topic is not independent from that which was previously explained under sheeting for shallow excavation but rather a continuation and improvement of the methods, application of new materials and approach. · 1. The use of timber sheeting on excavation that exceeds 4 to 5 meters depth is generally uneconomical; instead, steel sheet piles are driven along the property line of the excavation. The wales and struts are inserted as the soil is removed from the site. 2. Steel sheet piles are driven down to a meter length below the bed of the excavation to prevent local heaves, this embedment of steel sheet below the excavation bed sometimes eliminate the use of struts to support the lower portion of the sheeting.
63
3. The use of H pile is sometimes employed, driven along the property line of the excavation spaced at 1.20 to 2.50 meters eliminating the use of steel piles. The H piles are sometimes called soldier pile, installed with their flange parallel with the side of the excavation. 4. Horizontal wood board called lagging are inserted as the soil next to the pile is removed. As excavation advances from one level to another, wales and struts are inserted in the same manner as that of the steel sheeting. .......,
......., f
h. .,
~..,
··-
. SECTIO" Z-Z _ /
Figure 3-9. 5. There are instances where the central portion of the site is excavated to its final depth and then part of the permanent foundation is constructed. This structure then serves as the support for the inclined bracing or rakers when the remaining soil is excavated. ••.eoo.C) "••cro "' 8trO~l
"0~TIOM 0' lltllti'ORtt:O
Tllt:lltll
(xeava1oott OJ II£·.
MAI"l"G .OIL
C.ONCitETE tAFT f OVNOo\TION
Figure 3-10 6. Ahother method that is sometimes employed is the cross-lot bracing or inclined struts method called tieback.
fl""'l OltOUO lE . LE VE1.
3 - 7 SHEET PILES
Figure · 3 - 11
The different types of sheet piles used in excavation are: a. Flat web b. Arch web· c. Z piling
TABLE 3 - 1 AMERICAN STEEL SHEET PILES Section Number -Width Weight Wall Interlock- Strength US Steel Bethlehem in Per Kg. ing Lb./in. Kg.(Cm. Meter Sa. Ft. Sa. m. MZ 38 MZ32 MZ27 M 110 M 116 M 115 M 112 M 113 M 117
ZP38 ZP32 · ZP 27 DP 1 DP2 AP3 SP4 SP 5 SP 6a SP 7a AP8
.46 .53 .46 .41 .41 .50 .41 .41 .38 .38 .38
17
182 150 129 15 161 12 129 10 107 10.5 112 13 139 13 139 15 161 14 150 14 12
8,000 8,000 8,000 8,000 8,000 8,000 12,000 12,000 16,000 16,000_ 8,000
1.431 1.431 1.431 1..431 1,43f 1,431 2,147 2,147 2,863 2,863 1,431
65
ZP-32
ZP·38
Jr-\ L·· \ ,'l
. ~--16"
\\
.1,
Df>·Z
!:lP-1
·---19r---.-! AP·3
Some tvoes &nd dim.euiou o! America ewe! thee' pilee. {From
Figure 3- 12
66
TABLE3-2 KRUPP STEEL SHEET PILES SECTION
b mm
K:awP 8nKL 8auT Pn.u ·
h mm
ksla ksl kslb ksll kll
432 432 432 432 400
k'l
400
·320
kvl
400
320
160 160
160 181 181
(Fl'OIIl' eatalope o( Rbeinhaueeu A. G.)
~·~ ....._.ICidon
r
LI t1!J
~-cltMn(~ llllldiiiiiCIIIIdoliS
t=-.
-:..1
3-8 EXCAVATION IN SAND: The Characteristic of sand above the water table possess the quality of enough cohesion which facilitates the excavation work. Tests have been conducted and results show that settlement of the adjacent ground in large excavation does not exceed about 0.5% of the depth of the cut and that the influence thereof does not extend farther than equal the depth from the edge of the cut, when properly supported by sheeting and bracing called shoring. Excavation of sand extended below water table is of different approach , it is advisable to lower the water table before starting the exc~vation to minimize if not to avoid subsidence which is the usual nature of sand to sink down to lower level when springs are permitted to form at or near the bottom of the excavation. The water springs carry the materials into the excavation grain by grain that might produce a tunnel beneath the slightly cohesive layer that when sufficiently enlarged causes the roof to give way and the water above subside to form into a sink hole that may extend to a considerable distance from the edge of the excavation. Ditches must be cut at the bottom leading the water to a sump pit at a lower elevation than the rest ·of the excavation. The water level in the sump should be maintained at the lowest elevation; otherwise, wet sand becomes readily active in swallowing up any heavy object resting on it. When springs sprout out, the sand will start to boil; the slope will slough or drop off and the entire base
of the excavation might slope upward and the ditches around the edge of the excavation that emerge near the toe of the slope will cause the bank to collapse. The methods and processes of pumping is a matter of importance. Sufficient equipment is necessary just from the beginning of the work to guarantee the efficient removal of water without the necessity of making additions or alterations during the process. Inadequate pumping capacity wil! only lead to sand boils and instability of the excavation base.
3-9 ·. EXCAVATION IN CLAY . Large cut and deep excavation in soft clay develops lateral forces in the subsoil due to the weight of the earth surrounding the edge of the excavation which becomes a surcharge or additional pecuniary load, and if the depth of the cut becomes so great that the bearing capacity of the soil below the sides is reached, vibration and large movement become inevitable irrespective of the care which the sides may be shored or braced. The movement could only be decreased by driving piles around the cut braced by struts or the use of metal sheeting. If the lateral pressure is so great that metal sheeting could not withstand it. the use of steel piles is the last recourse.
Shoring- is the process of providing temporary supports to the. structure or ground during the excavation;"th is is sometimes called sheeting and bracing.
Heave- horizontal disp~acement of vein or stratum. Subsidence- sinking down, or sink to lower level•
. Settlement - the sinking or lowering of materials or struc· ture.
Underpinning - the operation of providing a permanent foundation in place of an inadequate footing, for instance, r• olacino a 41h"llnw fnotino bv,. nP.w fnntinn ;~~t a oreater deoth. 68
Comments and Observations: The excavation work involved irf continuous footing is a con· tinuous trench comparatively cheaper than that ofa series of sma.ll pits for isolated footing, moreso, the excavation work for a raft footing is not so much for it involved a simple broad shallow hole. If the construction requires bracing of the excavations aside from the forms necessary for the concrete work, less materials will be needed for the continuous. or raft foundation than that of the individual ·footings. Records of cost comparison of several projects show that a raft footing in some ways appears to be more econo· mical than individual footings whose total area occupied exceed 50 to 75% gross area of the building.
..
3- 10 FILLING 1. If the compressible materials is comparatively thin and is just below the original surface, it can. in some instances be removed economically thru excavatiors. 2. If it is very weak it is sometimes displaced by advancing the fill from one direction to another so that a mud wave is progressibly swept across the site. 3. The most suitable materials for filling on building sites are well graded sand and gravel but it is considered costly. 4. Fills are placed in layers usually not thicker than .15 m. (6") after compaction and compaction by equipment suitable to the type of soil. 5. Filling materials are often dumped into the enclosure
. loosely and then flooded in an attempt to compact them. This procedure although still widely used should not be permitted.. In cohesive backfill, it inevitably leads to weakenina and softening of the soil and to future loss ot support and subsidence 6. Clay with high swelling potential should be avoided as fill beneath foundations or fill to support floors. If the soil dries.
69
differential shrinkage will most likely happen and irregula r subsidence will develop. If the moistu re content increases, floors will crack thereby creating lateral forces on foundation walls. If there is no alternative material except the swelling clay for filling it is better to compact the materials somewhat with more water than at t he optimum moisture content because the effect of swelling is more damaging than those of shrinkage. 7. Treatment is necessary. The addition of lime may also be beneficial in improving the workability of clay and silts. The principal effect of lime is to reduce the free ~ater in the soil by hydration. It also reduces the plasticity of the d ay. The compacted soil w ill develop an add it ional strength an~ stiffness w ith time. Portland cement is seldom used fo r such a purpose because it is less effective in reducing the free water content of the soil although it may enhance strength in the clay later.
70
CHAPTER
4
·c0NCR ETE 4 - 1 CONCRETE Concrete is an artificial stone made out from the mixture of cement, sand, gravel and water or other inert materials; this is known as solid mass or plain concrete. Concrete in which reinforcement is embedded in sueh a manner that the two materials act together in resisting forces is called Reinforced Concrete.
4 - 2 CEMENT Of the various hydraulic cement which ha'-
4-3 AGGREGATE It is an inert granular materials such as natural sand, manufactured sand, gravel, crushed gravel, crushed stone, pebbles, vermiculite, pert ite, cinders, slag, etc. Aggregates are classified as fine and coarse that forms into concrete when bound together into a conglomerate mass .by a matrix or cement paste. Fine Aggregate diameter.
the materials smaller than 9 mm. in
Coarse Aggregate- the materials over 9 mm. in diameter. Coarse Aggregate vary In sizes from ( l/4" to 3") 6 mm to 76 mm the maximum size for a reinforced concrete is (1") 25 _mm 71
or {1 lh'') .38 mm. When a concrete member is small and the reinforcement spacings are close to each other, the coarse aggregate shall be oroperly graded at {¥4 .. to 13/4") 6 mm to 44 mm. 4-4 WATER The water .intended for use in concrete mixing shall be clean and free from injurious amounts of oils, acids, alkali, salts, organic materials or other substances that may be deleterious to concrete or steel. Water to be used for prestressed concrete or concrete which will contain aluminum embedments, shall be free from deleterious amounts of chloride-ion.
Conditions for maximum size of coarse aggregate 1. It shall easily fit into the forms and in-between reinforcing bars. 2. It should not be larger than 1/5 of the narrowest dimension of the forms or 1/3 of the depth of the slab nor lf4 of the minimum distance between the reinforcing bars. 4- 5 TYPES OF CONCRETE AND THEIR WEIGHT
1. Ugh t weight concrete 2. Medium stone concrete
3. Heavyweight concrete
Lightweight concrete- is classified into three types depending upon the kind of aggregates used in mixing, which predetermines their weight.
t--
a. Low density concrete- is employed for insulation purposes whose unit weight rarely exceeds 50 pounds per cubic foot or 800 kgjm3
b. Moderate-strength concrete - with unit weight from 960 to 360 kg. per cubic meter with a compressive strength of 70 to 176 kg. per square <:f'ntimeter is usually used to fill over light gage. steel floor panels. · c. Str~lWal concrete - has somewhat the same characteristics as that of medium stone coocrete and weighs from 90 to 120 pounds per cubic foot or 1440 to 1920 kg/ cu.m.
72
Med1um stone concrete ts a•so Known as structural concrete
weighing from 145 to 152 pounds per cubic foot generally assumed to be 150 pounds per cubic foot or 3300 kg/cum
Heavyweight concrete - is used for shielding against gamma and radiation in nuclear reactor and other s.imilar structure. This is also used as counter weight·for a lift bridge. The contents. of heavyweight concrete are cement, heavy iron ores, crushed rock, steel scraps, punchings or shot (as fine) is also used . . WEIGHT OF HEAVYWEIGHT CONCRETE The weight of the heavyweight concrete depends upon the kind of aggregate used in mixing:
1. Heavy rock aggregate - weighs 200 to 300 pounds per cu. ft. or 3,200 kg/cu. m. 2. Iron pa.1chings added to high density ores- 4,325 kg/ cum 3. Ores and steel - 330 lb/cu. ft or 5,300 kg/cum 4- 6
MIXING OF CONCRETE
The process of mixing concrete for building construction is done in two different ways either on site job-mixing or ready mixed concrete. The ACI Building Code so provides that: "For job-mixed concrete, mixing shall be done i~ a batch mixer of approved type. The mixer shall be rotated at a speed recommended by the manufacturer and mixing shall be continued for at least 1Yz minutes after all materials are in the . drum, unless a shorter time is shown to be satisfactory by the criteria of "Specification for Ready-Mixed Concrete for cen"tral mixers." Mixing of concrete shall be done until after a uniform distribution of the materials has been attained· and that the mixture shall be discharged completely before recharging the mixer.
73
Ready-mixed conaete. The concrete mixture from batching plant is most preferred, because the proportion of the materials such as cement and i!Qgregates are controlled by weight through a manual or automatic scale connected to the hoppers. Water is also batched either by a measuring tank or by water meter. The use of Ready-Mix concrete is suitable and convenient for constructions done in a congested city condition. Experienced builders have proven the Ready-mixed concrete to be more economical than the job-mixing processes. The Ready-mixed concrete is batched in a stationary plant then hauled to the site in any of the following manner:
1. Mixed completely then hauled by truck agitator. 2. Transit mixed-batched at the plant then mixed in a truck mixer. 3. Partially mixed at plant and completed in a truck mixer. The Bui lding Code specifies - "Concrete shall be conveyed from the mixer to the place of final deposit by methods which will prevent the separation or loss of materials. Conveying equipment shall be capable of providing a supply of concrete at the site of placement without separation of ingredients and without interruptions sufficient to permit loss of plasticity between successive increments." Concrete shou ld be discharged from the truck mixer within 1% hours after the water is poured to the batch. Conveying of concrete mixture is done by either: 4. Pumping through steel pipelines 1. Bottom dump 2. Buckets 5. Buggies 3. Wheelbarrows 6. G. I. pail Points to avoid in the placement of concrete to its final form : 1. 2. 3. 4.
74
Segregation of particles Displacement of forms Displacement of reinforcement in the form Poor bond between successive layers of concrete
Preparatton of equipment and depositing: Concrete mixing requires prior adequate preparation of equipment and materials for the activities. Sec. 5.1 of the ACI Code specifies: "Before concrete is placed, all equipment for mixing and transporting of concrete shall be cleaned, all debris and ice shall be removed from the spaces to be occupied by the concrete, forms shall be properly coated, masonry filler units that will be in contact with concrete shall be well drenched and the reinforcement shall be thoroughly cleaned ice or other dele- . ter ious coatings.''
of
'Water shall be removed from the place of deposit before concrete is placed unless a tremie is to be used or unless otherwise permitted by the Building Official." Building construction in a place where ice fall is not known or encountered. preparation of the site for pouring of concrete only embraces the removal of water, debris, mud, dirts, laitance and other unsound materials that will adversely affect the strength and durability of concrete. Depositing of Concrete. Depositing of concrete shall be made as early as practicable in its final place to avoid segregation of particles due to rehandling or flowing. Concrete shall be carried at all times in plastic form to flow re~dily into the spaces between the reinforcing steel bars. Concrete that has partially hardened or that has been contaminated by foreign materials shall not be deposited in the structure or retampering or remixing of concrete shall be made af~er the initial setting has started unless authorized by the Supervising Engineer. "After the concreting is started, it shall be carried on as a continuous operation until the placing of the panel or section is completed. All concrete shall be thoroughly consolidated by suitable means during placement and shall be thoroughly worked . around the reinforcement and ·embedded fixtures and into the corners of the forms." 75
Where difficulties are encountered particularly in areas congested with reinforcing bars, batches of mortar containing the same proportion of cement, sand and water as used in the concrete, shall be deposited first in the forms to a depth oH1 inch)25 mm.
then followed by the regular batch of concrete. 4 - 7 SEGREGATION Is the separation of sand and stone from the matrix or paste
that causes inferior quality of concrete. The causes of separation or segregatiQn of aggregates are: 1. Transferring of the concrete from the mixer to the forms. 2. Dropping of the concrete mixture from a high elevation 3. Improper tamping and spading 4. The use of long chutes 5. Excess amount of tamping, vibrating or puddling in the forms 6. Concrete particles tend to segregate because of their · dissimilarity. 7. Gravel tends to settle and the lighter materials and water also tend to rise inside a container when delayed in the delivery to the forms. 8. Lateral movement such as the flow within the form tends to separate the particles. 4 - 8 REOUI REMENTS FOR A GOOD QUALITY CONCRETE A premium quality of concrete is not just attained by mixing cement and aggregates, there are several considerations to be observed in order to produce a good quality of concrete:
1. Strenth and Durability of concrete is attained from the class of mixture or the right proportion of cement, aggregates and water~ 2. Workability - concrete mixture must be in plastic be P.lac.d in the form. ·
form and could readily 76
3. Dense. and Uniformity in Quality - concrete must be compact with un,iform distribution of particles in order to be water tight. 4. Curing - curing requires time, favorable temperature, and continuous presence of water or moisture in concrete. after pouring.
Factors that regutate the strength of concrete 1. 2. 3. 4. form. 5. curing.
Correct proportion Suitability or quality of the materials Proper methods in mixing Proper placement or depositing of concrete inside the Adequate protection of concrete during the period of
4-9 CURING The hardening of concrete depends upon the chemical reaction between the cement and water. Hardening of concrete will continue as long as moisture is present under a favorable temperature condition. The initial setting of concrete will start at about two or three hours after the concrete has been mixed. At this stage, concrete shall be properly protected to prevent craze due to rapid evapora· tion of moisture; 70% of concrete strength is reached at the. end of the 1st week and 30% could be lost by premature drying out of the concrete. The protection of concrete from loss of surface moisture is 7 days when ordinary portland cement is used and 3 days for an early high strength portland cement. The methods of ew-ing surface concrete are: 1. Covering of the surface with burlap continuously wet for the required period. 2. Covering of the slab with a layer of wet sand or saw dust l inch or 25 mm. thick. 77
3. Wet straw or hay on top of the slab continuously wet. 4. Continuous sprinkling of water on the slab surface. 5. Avoid early removal of forms; this will permit undue evaporation of moisture in the concrete. The Building Code on Curing so provides-" ... concrete shal! be maintained above lOOC temperature and in a moist condition for at least the first 7 days after placing, except that high-early strength concrete shall be so maintained for at least the first 3 days.... xx xxx Curing by high pressure ·steam at atmospheric pressure, heat and moisture or other accepted processes, may be employed to accelerate strength gain and reduce the time of curing." 4- 10 ADMIXTURE
Admixture is a material other than portland cement, aggregate, or water added to concrete to modify its properties. All admixture added to concrete serves as water repellent, coloring agent, increase workability, accelerate or retard the setting, harden its surface etc. The Code on admixture specifies "The admixture shall be shown capable of maintaining essentially the same composition and performance throughout the work as the product used in establishing concrete proportions .. . xx .. Admixtures containing chloride ions shall not be used in prestressed concrete or in concrete containing aluminum embedments if their use will produce a deleterious concentration of chloride-ion in the mixing water."
4 --11 CONCRETE PROPORTION AND WATER CEMENT RATIO
It has been mentioned that concrete proportion and water cement ratio plays an important role in the strenth and durability of concrete. There are two methods being adopted in proportion· ing concrete mixture; it is either by volume or by weight measure.
7&
TABLE 4- 1 CONCRETE PROPORTION
Class of Mixture
Cement Bag 40 kg.
Sand cu. ft. cu.m
-----,.A---=A------=,.1---=---....,1:7% A B
c
1 1
1
2
2Ya 3
.043 .057 .071
.085
Gravel cu. ft. cu.m.
3 4 5 6
.085 .113 .142
.170
The philosophy behind in establishing the proportion of fine and coarse aggregate is to create a solid mass where cement paste enters the voids of the fine aggregate and in turn fill the void of the coarse aggregate Theoretically, concrete proportion shows that sand is always one half the volume of gravel, for instance, 1 : 2 : 4 means 1 bag cement, 2 parts sand, and 4 parts gravel is the proportion for Class A concrete. Another way of expressing such proportion is 1 : 6 which simply means that for every bag cement, 6 parts of fine and coarse aggregate forms a class A mixture. Such idea does not necessarily fix the volume of the fine aggregate to be always Y:r the volume of gravel. Adopting the concrete proportion as presented in Table 4·1 is theoretically right and also correct as far as the specification is concerned. How if problems arise during the actual concreting work when segregation of aggregate could not be avoided, specially on portions where steel bars are crowded and closed to each other? In a situation like this where workable plasticity of concrete and other factors are adversely affected, correction and adjust· ment should be made immediately to prevent further damages. In this connection, the following solutions are suggested: 1. Verify the diameter .of the gravel, these might be bigger than what is required by the specification, if so then, order the right grade or have it passed the right screen. 2. Ascertain the thorough mixing of the concrete. 3. Verify if the proportion you are adopting, say 1 :2 : 4
79
mixture has enough paste to cover the gravel and the reinforcing bars including the pipes and other materials. to be embedded in the concrete. The paste of a concrete mixture should not only be enough to cover the gravel mixed but also the steel bars and other materials incorporated in the forms. This simple neglect will invite a building of a honeycombed structure. 4. Aggregate proportion could be adjusted say from 1 : 2 ; 4 to 1 : 2% : 3lh which is also equivalent to 1 : 6 mixture, this will reduce a little the gravel volume and at the same in~nce increase the paste to cover both the gravel and the steel bars Testshave.been con~ucted on such kind of adjusted proportion and the result was equally satisfactory. It has also been proven that the adjusted pro· portion is economical than the 1 : 2 : 4 mixture. 5. The concrete proportion where fine aggregate is always % th~ volume of the coarse aggregate is effective on a massive structure with less reinforcement and also on concrete slabs with consi· derable thickness like roads and the like.
TABLE 4 - 2 MAXIMUM PERMISSIBLE WATER- CEMENT RATIOS FOR CONCRl:TE (when strength data from trial batches or field experience are not available)
Specified Compressive Strength f's · Psi · kg/cm2 2500
3000
175 210
3500
245
4000 4500
280 315
80
Maximum permissible water-cement ratio Non-air entrained Air entrained Concrete Concrete Absolute Liters. per Absolute : Liters. per ratio by wt. bag cement ratio by wt. bag cement
. 0.65 0.58 0.51 0.44 0.30
27.6 25.0 22.0 19.0 16.3
0.54 0.46 0.40 0.35 0.30
23.1 19.7 17.0 15.1 12.9
There is no definite rule or formula that could give the exact amount of water per bag or batch of mixture to attain the desired workable plasticity of concrete. The Code on water cement ratio so provides. . "If suitable data from trial batches or field experience cannot be obtained, permission may be granted t o base concrete proportions on the water cement ratio. limits as shown in Table
4-2" . .. 'When made with normal weight aggregate, concrete that is intended to be watertight shall have a maximum water cement ratio of 0.48 for exposure to fresh water and 0.44 for exposure to sea water."
Air-entrained concrete is used extensively in the pavement of road construction, it resists frost action and cycles of wetting or freezing. It also provides higher immunity to surface scaling caused by chemicals. TABLE 4 - 3 CONCRETE AIR CONTENT FOR VARIOUS SIZES OR COARSE AGGREGATE Nominal maximum size of coarse: aggregate inches
mm
3/8 lf2 lf4 1 fl/2
9.5 12.7 19.0 25.4
2 3
51.0
38.0
76.0
Total air content percent by volume percent by volume
6 to 10
5 to 9 4 to 8 3.5 to 6.5 3 to 6 2.5 to 5.5 1.5 to 4.5
Comments and Observations l. Concrete shall be of plastic and workab le form, hence, it should neither be too dry nor too wet. Too dry concrete is dif· ficult to place in the form, because it resists packing around the reinforcement and corners of the form that honeycombing could not be avoided. 81
2. Too wet concrete results to the segregation of the ingredients. Water ratio is best determined by trial batch method to determine the kind of mixture in obtaining the required strength and consistency. 3. The water cement ratio shall be established during the first hour of mixing operation and adjustment shall be made under the following weather conditions: · a. On fair or cloudy weather b. Sunny day c. Rainy day
Fair or cloudy weather - at this weather conditio":~, adjustment of water-cement ratio is sometimes negligible or Uf!necessary because the moisture content of the aggregate will remain constant throughout the mixing operation. ·
On Sunny day - the regular mixing operation follows after the right water-cement ratio had been established in the first hour through the trial batch · method. As the sun rises, temperature increases which cause rapid evaporation· of aggregate moisture dumped on the batching site; consequently, adjust ing gradually t he water content per mixture batch is necessary. If m ixing will continue until after sunset, adjustment by reducing the water content ratio is sometime necessary to maintain a uniform mixture of concrete. On Rainy day - if rain occur any time after the water·cement ratio has been established, an immediate readjustment of water ratio is neccessary to maintain the uniformity of the mixture. Under this situation, a reduction of water content per mixture batch is inevitable. All conveying devices in de livering concrete shall be free from rain water before use.
4-12 TESTS <;:on crete should undergo tests specially those made of various proportions few days or weeks before the actual construction. The Building Officials has the right to order the testing of any materials used in concrete construction to determine if the concrete con-
82
forms wit.h the. quality specified. The c~mplete records of the tests shall be maintained and made accessible for inspection during the progress of the work and for a period of 2 years aner all and shall be preserved by the inspecting Architect or Engineer for re.ference purposes.
Consistency -
refers to the state of f luidity of fn~shly mixed
concrete.
1. Slump Test ·- this method of test requires a fabricated metal with the following dimensions:
lOtm
Figure 4- 1
Stump test procedures: a. · Place the freshly mixed concrete inside the mould in 3 layers each rodded sepMately by 16 mm rod 25 times. b. Level the mould and lift ·at once. c. Measure the slump action immediately by getting the difference in height between the height :.Jf the mould and fhe top of the slumped concrete. d. If the slump measure 10 em., It is said to be a 10 em. slump. • e. The degree of consistency of concrete could be ascertained on the following table:
83
. TABLE 4-4 RECOMMENDED SLUMPS FOR VARIOUS CONSTRUCTIONS
Types of construction
Maximum em
Reinforced foundation wall and footing Plain footings, caissons and substructure walls Slabs, beams and reinforced walls Building colums Pavement Heavy mass construction
Minimum em
13
5
10 15 15 7
2.5 7.5 7.5
7
5
2.5
2. Compression Test: This type of test is the process applied in determining the strength of concrete; the procedures , are as follows: a) For a coarse aggregate not more than 5 em. dia· meter, prepare a cylindrical specimen 15 em. diameter and 30 em. long b) For a coarse aggregate more than 5 em. diameter prepare a cylindrical specimen with a diameter 3 times the maximum size of the aggregate and a height double its diameter. c) The mould should be made of metal placed on a plane surface preferably 6 to 12 mm glass plate. d) Place the fresh concrete inside the mould in 3 separate equal layers rodded separately with 16 mm rod 25 · strokes. e) Level the surface with trowel and cover with a glass or plane steel. · f) After 4 hours, cover the specimen with a thin layer of cement paste and cover again with the planed metal or glass. ·g) After 24 hours, curing shall be made in a moist atmosphere at 21° C. h) Test should be done at 7 and 28 days period. i} Ascertain that both ends of the specimen are per· fectly levelled.
84
j) Specimen is placed under a testing machine; then a compressive load is applied until the specimen fails. The load that makes the specimen fail is recorded. k) The recorded load divided by the cross sectional area of the cylinder gives the ultimate compressive unit stress of the sample.
Gaga
. .. .: ..··:: ...... .• '. -:_t•
Figure 4-2
CHAPTER
5
METAL. REINFORCEMENT 5-1 STEEL REINFORCEMENT Steel is the most widely used reinforcing materials in most constructions. It is an excellent partner of concrete in resisting both tension and compression stresses. Comparativeiy, steel is ten times stronger than concrete in resisting compression load and 100 times stronger in tensile stress. The design of reinforced concrete assumes· that concrete and steel reinforcements act together in resisting load and likewise to be in the state of simultaneous deformation, otherwise due to excessive load, steel bars might slip from the concrete in the absence of suf· ficient bond. Und.er this assumption, the load between the concrete and steel should be sufficiently strong to prevent any relative movements of steel bars and the surrounding concrete. In order to provide a high degree of interlocking between the two materials, a steel reinforc·. ing bar with a surface deformation in various sizes in diameters were introduced.
Type's of deformed bars Figure 5-1 The combtnation of concrete and steel shows the following satisfactory joint performance: 1. There is a negligible difference in thermal expansion coefficient that makes it safe from undue effects of differential thermal deformation. 2. The concrete that surrounds the steel reinforcement is
86
considered an excellent protective covering that retards corrosion in steel. 3. The strength of steel when exposed to high temperature substantially decreases, but concrete covering provides a suffi· cient thermal insulation. 4. While concrete is weak in tension force, steel has that property in resisting high tensile stresses
Steel could be used in two different ways: ~,As reinforcing steel, it is placed in the forms before the pourin of fresh concrete. . ~ As prestressed steel, heavy tension forces are applied to the steel reinforcement before the casting of concrete.
5-2 STEEL BARS FROM ENGLISH TO METRIC MEASURE Steel bar diameters have been standardized from '14" to 2114" and the length varies from 20', 25', 30', 35' and 40' long. Aside from these standard diameter measurements. a corresponding number were introduced and designated to each diameter size for convenience and proper identification. For instance, a number 2 bar is 114'' f/J No. 3 is 3/8''¢J bars etc. From these examples one could easily determine the diameter of bars by dividing the designated number by 8. In short, the diameter of bars differ from the con· secutive numbering by 1/8". TABLE 5 - l DESIGNATIONS, AREAS, PER.IMt;TER$ & WEIGI.ITS OF STANDARD BARS CroesUnit weight Perimeter, sectional ·pet foot, lb in. Diameter, in. area, •m. t Bar No. 2 3
" 5 6
1 8
9 10 11
14 18
i- 0.250 1- o.a75
-t- 0.500
i- 0.625 f-0.750 f .. 0.875
0.05. 0.11 0.20 0.31 0.44
0.79 1.18 1.57 1.96 2.36
0.167 0.376 0.668 1.043 1.502 2.044-2.. 670
0.60
2.75
1 - 1.000 I i - 1.128
0.79
3.14
1.00
3.54
It,. 1.270
1.27 1.56
3.99
4.43
3.400 4.303 5.313
2.25 4.00
5.32 7.09
13.600
l f - 1.410 lf- 1.693 2f ... 2 257
1.650
87
TABLE 5-2 AREAS OF GROUPS OF STANDARD BARS, IN SQUARE INCHES NvMkr o/.&oN
B'lr
3 • 5 -0.78 0.98 0.39
2
No.
~
4
s 6 7
8 9 10
11 14 18
0.61
0.88 1.20 1.57 2.00 2!13 3.12
4.50 8.00
6
7
8
t
10
11
12
13
14.
-- -- -- -- -- ---- --
118 1.37 1.57 1.77 1.96 2.16 2.38 2.$5 2.75 3.6~ 3.09 4.30 1.32 1.11 2.21 2.65 3.09 3.53 3.98 4.42 4.86 5.3C 6.74 6.19 1.80 2.61 3.01 3.61 4 21 4.81 5.<41 6.01 6.61 7.22 7.82 8.4.2 2.35 3.H 3.93 4.71 s.so 6.·28 7.07 7.85 8.64 9.43 10.21 11.00 3.00 4.00 500 6.00 7.00 8 00 9.00 10.00 11.00 12.00 13.00 14.00 3.79 5.06 6 33 7.59 8.86 10.12 11.39 12.66 13 92 15.19 16.4.5 17.72 ' 68 6 25 7 81 9 37 10 94 12..'i0 14.00 15.62 17,19 18.75 20.31 21.87 6.75 900 11.25 l.'J50 15.75 18.00 20.2.') 22.50 24.75 27.00 29.25 31.50 12 00 16 00 20 00 24.00f2s.oo 32.00 36.00 40.00 44.00 48.00 52.00 56.00 0.58 0.91
1.23 1.53 1.84 2.15 2.45 2.76 3.07 3.37
Recently the great confusion arose after the intoduction of the Sl Metric System in all kinds of measure. Steel bar manufacturers in the guise of conforming with the international movement as emphasized through a presidential decree produced steel bars that slightly differ by millimeter. Manufacturers produced steel bars with their own standard under the millimeter diameter and was allegedly referreq to as "standard" (that which refer to the English measure); below standard; oversize; undersize; mm; etc. which created confusion even among technical men. The production of steel bars that slightly differ by a millimeter in diameter was pur· posely designed to cater on the buyers who in these time of eco· nomic crisis prefer the cheaper steel bars. As a result. customers· disregard the diameter size whether the materials that they are buying are smaller than what is specified. As an outcome, there is a total sacrifice in the strength of the structure.
COMMENTS AND ANALYSIS 1. How could one distinguish the difference between 10 mm from 11 mm steel bars through the naked eye without the aid o; a caliper? Even with the aid of'a caliper, one could not effectively measure a steel bar with perforations and elliptical cross-sectional diameter.
88
2. The former measure that differ by 1/8" could be easily noticed and distinguished by anybody even without the aid of a caliper. To be able to buy the right diameter of steel bar: a· Verify the weight per meter or weight per bar length with the aid of Table 5-3 and 5-4 b. Order of steel bars shall be specific according to the millime.ter sizes such as 12 mm. Avoid the '112"
4. The different steel bar manufacturers must be compelled to strictly follow a standard of measurement of steel bars through a more specific order. Guideline must be provided in the manufac ture of standard steel bars for protection of the public from unscrupulous manufacturers and suppliers. 6
TABLE 5-3 ST ANOARD WEIGHT OF REINFORCING BARS
NOM UNIT Near AS T M 10.5M 12M 9M 6M 7.5M Dia. wt (19.68') 24.6') -(29.52') (34,44') (39.36') Kg. Kg. (mrn) Kg.- (M) Designation Kg. Kg . Kg. 6 10 12 16 20 25 28 32 36
.222 .616 .888 1.579 2.466 3.854 4.833 6.313 7.991
No.2 No.3 No.4 No.5 . No.6 No.8 No.9 No. 10 No.ll
1.332 3.696 5.328 9.474 14.796 23.124 28.998 37.878 47.946
1.665 4.620 6.660 11.843 18.495 28.905 36.248 47.348 59.933
2.000 5.544 7.992 14.211 22.194 34.686 43.497 56.817 71.919
2.331 6.468 9.324 16.580 25.893 40.467 50.747 66.286 83.906
2.664 7.392 10.656 18.948 29.592 46.248 57.996 75.756 95.892
89
TABLE 5-4 PHILIPPINE STANDARD COMPARED WITH ASTM STANDARD (SECTIONAL AREA) Philippine Nominal Standard Sectional . Designation Area mm
6 (mm}
10 (mm) 12 (mm) 16 fmm) 20 (mm} 25 (mm} 28 (mm) 32 (mm) 36 (mm}
28.27 78.54 113.10 201.10 314.2
491.9 615.75
804.25 1017.9
2
Unit Weight Kilogram/ Meter
REMARKS
0.222 10.7% smaller than ASTM No. 2 0.616 10.22% larger than ASTM No. 3 9.887 10.7% smaller than ASTM No.4 1.577 1.6% larger than ASTM No. 5 2.463 10.22% larger than ASTM No.6 3.848 2.9% smaller than ASTM No.8. 4.827 4.49<¥o smaller than ASTM No. 9 ~.305
7.980
1.6% smaller than ASTM No. 10 .97% larger than ASTM No.n
TABLE 5-5 STEEL GRADE AND STRENGTH PER mm 2
ASTM Philippine STANDARD
Grade 60 Intermediate Grade 40 . Structural Grade
Yield Point/Strength
(minimum} (minimum) Newton/ Kg. Force psi Newton/Kg. Fo·rc:e psi mm 2 mm 2 mm 2 mm 2 Grade 410 41.808 60.00
620 63.22 90,000
Grade 275 28.042 40,000 480 48.95 70,000 Grade 230 24.453 33,350 390 39.77 55,000
5-3 PRESTRESSED STEEL Prestressed steel is used in three forms:
1. Wire strand 2. Single wire 3. High strength bar 90
Tensile Strength
The wire strand are of even wire types where the center wire is enclosed rigidly by hexagonal outer wires with a pitch of 12 to 16 times the nominal diameter of the strand. The diameter of the strand ranges from 1!4 to 1fz inch (6mmto 12mm). Prestressing wire diamet~r ranges from .192 to .276 in. (5 to 7mm) made out from cold drawn high carbon steel. High strength alloy steel bars for prestressing ranges from 3/4" to 1 3/8" {20 to 36 mm) diameter.
5-4 WELDED WIRE FABRIC Aside from the individual reinforcing bars, welded fabric is sometimes used for reinforcing concrete slab and other similar structure such as shells. Siz• and spacing of wire may be similar for both ways or might be different depending upon the detail of the design.
5-5 IDENTIFICATION OF STEEL BARS How to distinguish the different grades and sizes of bars is a problem that one might accidentally use a lower strength or smaller size of steel bars from what is being required. All deformed bars are provided with distinctive markings iden· tifying the· manufacturer usually by an initial and the bar size number from 3 to 18 including the type of steel such as: A- for Axle
N - for Billet
Rail sign- for rail steel
Additional marking for identifying high strength steel bars:
• •
~·• 1. ~~~ c•~ •o 1.....0 ... ~~1:)· 1$
,...s
Marking System Figure 5-2
91
TABLE 5-6 STANDARDIZED REINFORCING AND PRESTRESSING STEELS
Product Reinforcing Bar
ASTM Specification
G"de 40
A615 A616 A617
60
50 60
40 60 60
A706 Bar mats Wire, smoth Deformed Welded wire fabric, smooth Deformed Prestress Bar Prestress wire Prestress Strand
Minimum Yield Strength KSI MPa 40 60 50. 60 40 60
60
*Al84,*A704 A82 A496
(78max) 70 75 75
A185 A497 A722
65 70 127.5
Type 1 Type II
A421
120 188-200
A416
250
270
Minirnum Tensile Stren9th KSI MPa
276 414
70 90
483
620
345
80
414 276 414 414 (538 max) 483
90
80
552
517
85
586
517
85
586
448
75
483
80
517 550
70 90 80
880
552 620 483
620 552
1034 150 1034 150 1296-1330 235-250 1620-1725
212.5 229.5
827
1465 1580
250
270
1725 1860
* Same as reinforcing Bars
TABLE 5-7 MINIMUM DIAMETERS OF BEND FOK STANDARD HOOK Bar Size
Minimum Diameter
No.3 -8 No.9 -11 No. 14-- 18
6 bar diameter 8 bar diameter 10 bar diameter
Example : lf2" (l.l/ em} rounu uo• "v "'"' .....cuneter"'" 3 inches or 7.6 em. diameter for hook. Note: Hooks are not effective in adding compression resistance of reinforcement.
92
Figure 5-3 Standard Hook
5 - 6 BAR CUT OFF AND BEND POINTS 1. Every bar ~hould be continued to at least a distance to the effective depth of the beam or 12 bar diameter whichever is larger. 2. The Code requires that at least 1/3 of the positive moment of steel (bottom bars) must be continued uninterrupted along the sam~ face of the beam a distance of at least 6 inches ( 15 em) into the support. 3. At least 1/3 of the negative moment reinforcing bars Should be extended beyond the extreme position not less than 1/16 the clear beam whichever ~s the grMter.
~~~-------
,....... -----+f EndS,.
Figure 5-4 93
5- 7 BAR SPLICING 1. Tension bars may be spliced through: a. weld ing b. sleeves c. tying d. mechanical devices which provides full positive connection between the bars.
2. Compression bars may be spliced by: a. tapping b. direct end bearing c. welding d. mechanical device which will provide full positive connection. .
..
The Code specif ies·. the compressive splice should not be less than 12 inches (30 em) long."
5-8 BARSPACING 1. The ACI Code specifies that the minimum clear distances between the adjacent steel bars shall not _be less than the nominal diameter of the bars or 1 inch 25 mm. for column, this requirement was increased to ll/2 bar diameter or ! 1/2 inches or 4 em. 2. Where beam reinforcement are placed in two or more layers, the clear distances between layers must be. not be less than l -inch (25 mm.) and the ·bars in the upper layer should be placed directly above those in the bottom layers. · 3. In walls and slabs other than concrete joist construction, the p rincipal reinforcement shall be spaced not farther apart than three times the wall or slab thickness nor-more than 18 inches or 45cm . 4. The clear distance between pretensioning steel at each end of the member shall be not less than four times the diameter of individual w ires nor three time~ the diameter of the strand~ 5. The clear spacing between spirals shall not exceed 3 inches (7.5 em.) odess than 1 inch (25 mm), havi.ng a minimum diameter
94
of 10 mm. Spiral splices shall be48 b4ar diameter minimum but not less than 12 inches (30 em.) or welded. · 6. Lateral ties shalf be at least no. 3 bars spaced not to exceed 16 times the longitudinal bar diameter or 48 tie bar diameter orr the least dimension of the column. 7. Shrinkage and temperature reinforcement shall not be · placed farther apart than 5 times the slab thickness nor more than 18 inches or 45 em.
5-9 CONCRETE PROTECTION FOR REINFORCEMENT The following minimum concrete c.over shall be provided for reinforcing bars, prestessing tendons, or ducts. For bar bundles the minimum cover shall equal the equivalent of the bundle but should not be more than 2 inches (5 em.) or the tabulated minimum, whichever is greater. · '
TABLE 5-8 PROTECTIVE COVERING FOR STEEL REINFORCEMENT Minimum cover in Inches em.* Cast-in place concrete (non-prestressed) Cast against and perrreanently exposed to earth
3
8.0
Exp~d
to earth or weather: _ No. 6 through No. 18 bars • • • • • • • • • • • • • 2 No. 5 bins 16 mm. wire and smaller ..•..•••.·Hz
5.0 4.0
Not exposed to weather nor in contact with the ground: Slabs, walls, joists: No. 14 and No. 18 bars . • • • • • • . . . • . No. 11 and smaller • • • . • . • • • • • . • • . •
l!!z 3/4
4.0 2.0
Beams, girders, columns: · Principal reinforcement, ties stirrups or spirals •. ·• • . . • . . . . . • • • • . . . . • • • .
l!!z
4.0-
Shells and folded plate members: No. 6 bars and larger • • • • • • • • • • . • • . No.5 bars 16 mm. wire and smaller • . •
3/4 liz
2.0 1.5
95
Pre-cast Concrete (manufactured under plant} control conditions)
Min imum cover in tnches em.*
Exposed to earth or weather: Wall panels: No. 14 and No. 18 bars . . . . . • . . • . . . . . . • . No. 11 and smaller . . . . . . . . . . . . . . . • . . . . .
3/4
Other members: No. 14 and No. 18 bars . . . . . . . . . . . . • . . . . No. 6 through No. 11 .. : . . . . . . . . . . . . . . .•. No. 5 bars, 16 mm. wire and smaller . . . . . . .
2 11f2 lit'•
1112
4.0 2.0 5.0 4.0
Not exposed to Weather nor in contanct with the ground: Slabs, walls, joists: No. 14 and No. 18 bars . . . . . . . . . . . . . . . . lV• No. 11 and smaller ............•...•... 5/8
3.2 1.0
Beams, girders, columns: Principal reinforcements . . . . . . . . . . . . . . . . llfz Ties, stirrups or spirals .. ..... . .·. . . . . . . • 3/8
4.0 1.0
Shells and felded place members: No. 6 bars and larger ................ . 5/8 No. 5 bars, 16 mm. wire and smaller . 3/8
1.6 1.0
*Values rounded to the next whole number. Pre--stressed concrete members-prestressed and non- Minimum Cover prestressed reinforcements, ducts and end fittings Inches em.
3
8.0
Exposed to earth or weather: Wall panels, slabs and joists . . . . . . • • • . . . . . . . . 1 Other members ...............•..•........ llf2
2.5 4.0
Not exposed to weather not in contact with the ground; Slab, walls joists . . . . . . . . . . . . . . . • . . . . . . . . . 3/4
2.0
Cast against and permanently exposed to earth
96
Beams, girders, columns: Principal reinforcements. . • . • . • . • . • . • . • • • l'h Ties, stirrups or spirals • • • • • • • . • • . • . • • • . • 1
4.0 2.5
Shells and folded plate members: Reinforcement 16 mm. and smaller • • • • • • • • 3/8 Other reinforcements • • • . • • . . . • . . • . . . . . . 3/4
1.0 2.0
TABLE 5-9 PHILIPPINE STANDARD STEEL BARS COMPARED WITH ASTM STANDARD: DESIGNATIONS, AREAS AND UNIT WEIGHT PER METER Cross Unit weight Bar No. Nominal Diameter· Sectional Area per meter Inches mm (mm}2 kilogram kg. 2 3 4 5
6 7 8 9 10
11 14
18
1!4 3/8 ll2 5/8 3/4 7/8 1 11/8 ll/4 1 3/8 1 3/4 21/4
6 10 12 16 20 22 25 28 32 36 45 57
28.27 78.54 113.10 201.10 314.2 280.13 490.87 615.75 804.25 1,017.9 1,590.43 2.551.76
0.222 0.616 0.887 1.577 2.463 2.980 3.848 4.827 6.305 7.980 12.469 20.005
5-10 BUNDLE OF BARS For large girders and columns, bundle bars is allowed and these bundle act as one unit reinforcement with no more than 4 in any bundle provided that stirrups or ties enclosed the bundle. The Code specifies that: 1. Not more than two bars shall be bundled in one plane 2. Typical bundle shape are triangular, square or L-shaped pattern. 3. Bars larger than No. 11 shall not be bundled in beams or girders. . 4. Individual bars in a bundle cut off within the span of flexural members shall terminate at different points with at least·40 bar diameters staggered. 97
5- 11 CONTROL OF CRACKS
1. Cracks are minimized through the use of deformed steel bars. 2. A larger number of small bars is more effective in minimizing crack width than a smaller number of large bars having the same total cross-sectional area. ·
5-12 METAL REINFORCEMENT SPECIFICATIONS: The ACI building code requirements for reinforced concrete Specifies; 1. Deformed Billet-Steel Bars for Concrete Reinforcement shall be (ASTM A615). If No. 14 or 18 bars meeting this · specifications are to be bent, they shall also be capable of being bent, 90 degrees at a minimum temperature fo 42° C around a ten-bar diameter pin without cracking transverse to the axis of the bar. 2. Rail-Steel Deformed Bars = (ASTM A616). If bars are to be bent, they shall meet the bending requirements of AS.TM 614 3. Axle-Steel Deformed Bars = Shall be ASTM A617 4. Bar and rod mats for concrete re inforcement shall be the dipped type conforming with the Specifications for ASTM A184. 5. Plain wire for spiral reinforcement shall be Cold-Drawn Steel wire for concrete reinforcement ASTM A82. 6. Welded plain wire fabric for concrete reinforcement shall conform to the specifications of Welded Steel Wire Fabric ASTM A185. Welding intersections shall be spaced not farther apart than 30 em in the direction of th~ principal reinforcement. 8. Welded deformed wire fabric for concrete reinforcement shall conform to the specification for of ASTM A497. Welded intersection shall be spaced not farther apart than 40 em in the direction of the principal reinforcement. 9. Wire and tendons in prestressed concrete shall conform with the specifications for Uncoated Seven-wire ·Stress98
Relieved Strand for Prestressed Concrete ASTM A416 or ASTM A421. Strands other than A416 or A421 may be used provided that they conform to the minimum require· f ments of these specifications and have no properties which make them less satisfactory than those listed under A416 or A421. · Grade B of specifications for welded and seamless steel pipe ASTM A53. 11 . . Specifications for Structural Steel ASTM A36 12. Specifications for High Strength Low Alloy Structural Steel ASTM A242 13. For High-Strength Structural Steel ASTM.A440 14. High-Strength Low Alloy Structural Manganese Vanadium Steel ASTM A441. 15. High-Strength Low Alloy Columbium-Vanadium Steel of Structural Quality ASTM A572 16. For High Strength Low-Alloy Structural Steel with 50,000 psi or 344,7!?0 kPa minimum yield point to 10 em thick ASTM A588. It is interesting to note that the present manufactured steel bars is either smaller or larger in cross sectional area compared to the· ASTM standard as shown ~~:m Table 5-4. In the absence of standard specifications that regulates the manufacture of steel bars when the Metric System super<:eded the English Measure, manufacturers produced steel bars having diameters. at almost in increment of one millimeter which created problems and confusion. Lately the Board of Standard has agreed to standardize the manufacture of steel bar diameters as follows: Diameter Millimeter Bar No. Inches Equivalent Designation If• . . . . . . . . . . . . . . 1 mm 2 3 3/8 ............... lOmm lf2. . . . .. . . . . . . . . . 13 mm 4 5 5/8. ..... ........ 16 mm 6 3f4............... 20 mm 1· ................ 25 mm 8 9 1 1/8" . .. ......•... 30 mm 1 lf• . . . . . . . . . . . . . . . 35 mm 10 1 3/8 .............. 40 mm 11 1 3f4 • •.•••••••. •. • . 45 mm 14 211• •.....•. : •.... •. 60 rnm 18
k.
10.
99
CHAPTER
6
FOUNDATION 6- 1 MIEF HII10RY Builders and laymen throughout the ages have realized the importance of building structure on • strong foundation. Jesus Christ on his remarkable sermon before the multitude of people said: ''Therefore, whoso.v• h,areth these saying of mine, and doeth them, I will liken him unto a wise man, which built his house upon a r.ock. And the rain descend, and the floods came, and the winds blew, and beat upon the house: and It fell not: for it was founded upon the rcx:k."
Mathew 7 : 24- 26
The advanced knowledge brought about by the science ot Geology and Soil Mechanics have confirmed the rock foundation bed to be the most stable medium where to lay the footing of a structure. The early builders of the Babylonian Empire constructed Raft or Mat Foundation from out of the sun-dried and burned brid
~uit
100
The Romal)i Builders, introduced various foundation type to the ~~~! ce)nditions. Wood piles were used .on a very soft
ground and . wooden mats were laid underground where masonry structure were built upon them, the Roman builders further developed the construction of Built-up foundation consisting of flat stone bonded with Roman cement which. unfortunately, this early use of concrete has been forgotten during the Middle Ages. The introduction of the Griltage Footing resolves the problem of foundation weight in the year 1880 when it was first introduced. Consequently, the improved grillage footing made of steel· rail embedded in concrete was introduced in Chicago by John Root in the year 1891. The advent of Reinforced Concrete in the early part of 1890 superceded all these kind of footings due to the advantages it offers in al. l aspect of building construction. Foundations Foundation .is that portion of the structural elements that carry or support the superstructure of the building. Foundation is further defined as the substructure wh1ch is usually placed below the surface of the ground that transmits the load of the building to the under-lying soil or rock. Footing Footing is that portion of the foundation of. a structure which directly transmits the column load to the underlaying soil or rock. In short, footing is the lower portion of the foundation structure.
Fomdation Bed -refers to the soil or rock directly beneath the footing.
.COl. UN
·,.oottllo
Figure 6-1 Foundation Nomenclature
101
Footings are classified into two types, the wall and column footings. Walt footings is a strip of reinforced concrete wider than the wall which distributes the load to the soil. Column footing on the otherhand, is also classified into the following types: 1. 2. 3. 4. 5. 6.
Isolated or Independent footing Combined footing Continuous footing Raft or Mat footing Pile footing or foundation Grillage footing
6- 2 WALL FOOTING In wall footing, the main reinforcements are pla_ced at right angle perpendicular to the wall uniformly spaced with each other Longitudinal reinforcement parallel with the wall are laid to assist in bridging soft portion associated with the almost uncertain varia· tion of soil conditions. A steel percentage equals to 0.2 to 0.3% of the cross sectional area of concrete is said to be adequate except on unusual cases. -I-'-
~::.:_~-,~ ;r_-rrp~ij
I• ~0 _ 60 em 1-
I 15 em
;; v~~.~p· · · .· ~·
Property LlneL,.I------1
Figure 6-2
6- 3 ISOLATED OR INDEPENDENT FOOTING This kind of footing represents the simplest and most economical type usually in the form of: a. Square Block Footing b. Square Slope Footing c. Square Stepped Footing
w
0
.....
240
le
16
.
D~tb,
I
$-4
12-10
13...
11-3 11-10 12-3
to-e
10.2
8-11 .9-8
8-2
7-6
6-7
6-D
..a ·
8-4
...
28 lU
22
21
16-8
15-8
16-7 17-7 18-7
18 19 20
21
ltl · 19-6
17
14--6
11-5
11-4
16-5 13-6
16
10 10 12 13 14
40
80
16-8
15-3
560 600
520
480
uo
400
320 360
13-6 .15-6 17-6 19-6
16-7 17-7 18-7
240
280
200
160
120
20 22
liO
18· 20
16 16 16 16 18
12 12 14 H
12
Footln&
t
' r.2500- r.3000-
B~E&c.hW~q
Width
12-5 12-10
11-11
11-0 11-6
9-11 10-5
'l1 28 30 30
'P
25
24
21
16-9 17-9
15-9
23
8-8 9-3
19
12-9 14-9
14-6 17-6 15-7 17-7 14-8
7-4
20
1-'
8-Q
16
15
12-4 16-4 14-5 12-6
10
12
a-3
4-7 6-8 6-6
64
17~
14-9 16-9 16-9
12-9
14-3
14-6 17-6 15-7 17-7
H-5 12-6
t().J;
11-4
~
100
650 700 750 800
600
~
31;0 400 450 500
200 250 300
150
•
u
2ll 22 24
22
1'\-In.
Wid&h.
~·
Sq. :l'oo._
No.Si~e
-
1Z.O
11-7
lo-4 10.9 11-2
9-ll
8-11 9-5
s-s
7-10
7-3
4·2 5-1 6-11 6-1
21
82
28 29 31 31
25 26 28
28 24
13 16 17 19
17-3 19-8 20-8 17-8 18-11
17-6 16-7 17-7 16-8 16-3
17-5 15-6
111-5
16-4
13-'
11--6
17-8 19-8 20-8 17-9 18-9
16-7 17-7 14-3 16-8
13-7
16-5 12-6 15-6
11-4
No.Sise
---
r.3000r.2l500
B.nEaohW~q
Soil ~ure-6000 ptl
16 18 18 20 20
14 16 16
12 12
Q.
'-3" clear
3 "... 1-
la. ~ ~ Cal
uniformly spaced ),
Width, ~tb. l't-In. . No. SUe No.Sise
Sq.
r
I
I
II
' Two-way reinforcement
Soil ~re-4000 . .
...
Col. Lotod, ~c..L l(jpe In.
15--6
14-5
8-4
&-4 7--6 11-6
No. Si~e No. Si~e
--r--
r.2600- r.8000-
Ban E&ch W,.y
Soil~2000psf
F~In .
Width,
8q. Footi.Da
3000 J)lli
.. - 10 '· 1360,. • -- 75 .,., " .. 240 poi
J'. -
• Reproduced lice doe Amerie11n Coocre~ lul.itu'- aeiaj(IIICIIIl Ccma.U [).,i,.,. HoNl'-11:.
aoo
280
260
16 16
lt
220
160 180 200
140
12 12 14 lt It
12 12 12 12 12
120
100
80
eo
40
20
~·
Col. ~Col. la.
...
••75
,,.Ew. ·- .,.
20,000 l* 1:"... . -~PI' - 12
TABLE6-l SAFE LOAD FOR SQUARE IN[)EPENOENTCOLUMN FOOTING
The reinforcement for square footing is usually placed in the direction parallel to both sides spaced uniformly and perpendicular with each other.
I.
I I' I
I
I &.
•
•
.J ...
I
SQUARE 8LOCK
SQUARE SLOPED
SQUARE STEPPED
Figure 6-3 To use the above table consider the following example: Problem: A square column with a general dimension of 12" x 12" is to support an axial load of 100,000 lb. with the following data: Bearing capacity of soil= 2,000 psf f'c for concrete = 2,500 psi fc for concrete = 1,125 psi fs for steel = 20;000 psi Determine the dimensions and reinforcement for a two-way square footing:
Solution:
1. By illustrative analysis L0-'0 -
0 li'"
104
1z..
Figure 6-3
10
,00~ 1~.
2. Referring to the Table 6 -1; under soil pressure fs.= 20,000 psf the value along 100 kips Joad and column size 12"- the width of the footing will be 7'- 5 .. while the depth is 14". 3. The number and size of reinforcement under f'c =2,500 psi are 14 pes. of No.5 steel bars one-way. . 4. Since the reinforcement is two-way, another 14 pes. No.5 is necessary on the opposite direction. 5. The footing will then be as follows;
It Pt5.
*/J lfAqS-
•OTH WAYS.
j .....
"""I
Figure 6- 3b Tt~e
effective use of Table 6-1 could be either: 1. To determine the dimension of the concrete footing and the size of the reinforcement Including its spacing. 2. To determine the load that could be carried by a footing of a given dimension and reinforcement. .
PROBLEM: The values given on Table 6-1 and the accompanying illustration were· all in English measure. Solve for its equivalent in Metric System using the following convertion factor: Multiply. pounds per square foot pounds per square fo9t pounds per square inch pounds per square inch inch kips
by (psf) (psf) (psi) (psi)
47.88 4.882 .074 .703 2.54 454.5
. to get pascals kg./sq.m. kg.fsq. em. kg./sq. m •
em. kilograms 105
6- 4 COMBINED FOOTING The use of independent footing for extension columns sometimes meet difficulties on property line were footing projection beyond the exterior wall is not allowed. Under this situation, com~ bined footing or strip footing is employed to avoid tncroachment to an adjoinin~ property and at the same time satisfy the bearing capacity requirement of the foundation. Combined footing is ·em· ployed when two or more columns are spaced closely to each other that their footing will almost or completely merge . The main reinforcement in a combined footing is laid along the longi· tudinal direction assuming that the footing acts ~s one way slab. Transverse reinforcement is also placed at the bottom of the footing near the column where the critical section for transverse bend- · ing is taken at the faG'S of the column pedestal. Consequently, footing reinforcementS are spaced closely to the center of the column than the outer portion. Combined footing is either:
a. Rectangular
.
11 I
I
I
b. Trapezoidal Tlt•"~ZOIUL
1-----J .
•,
I
Figure 6 7'"· 4
106
'
6 - 5 CONTINUOUS FOOTING Continuous footing is sometimes classified as wall footing which supports sev~ral columns in a row. It is either: a. Inverted Slab Footing b. Inverted Tee Footing
Gt~O
FOUNDATIOI'I
INVERTED- T
Figure 6 - 5
6 - 6 RAFT OR MAT FOOTING Unless deep foundation is required by the soil condition, Raft footing is preferred. This type of footing occupies the entire area beneath the structure and carry the wall and the column loads. When a building is too heavy that individual or combined footing would cover about 'h of the building area, the Raft' footing is likely to be economical. The Raft footing is either made of an inverted slab provided with a .capital or pedestal at the bottom of the column or an· inverted slab with partitions as the stem ofT-Beam connected to the raft where the column rests at their intersections. Other types · are shown in Figure 6-6.
107
CANTILEVER FOOTING
::
:: : A
UNif'ORllll SLAS
C
BEA!Iol &. GIA0£.11
II
TMICitEMED
D . T·UAM WITH IMDEP!:MDUT
RAFT OR MAT FOUNDAlION
Figure 6·6
108
SLAB
,.LOOII.
6 - 7 PILE FOUNDATION When a foundation bid fs too weak to support o Raft footing, there is on urgent need to provide o suitable material where to transfer the excess load to a greater depth wherein piles or pier is the answer.
6-8 PILES The use' of piles have been employed by the early builders to support private and public buildings which was found iri the construction of the Romans. The brJdge across the Rhine ·River is afso supported by piles constructed during the rule of Julius C:oesor. Piles were Jikewise found near the lake of Lucerne and New Guinea, construction which where built about A.D. 200. The Campanile of Venice after its destruction have been found oUt to be resting on wood pHes which according to history has been driven os .arly as A.D. 900 and yet after the destruction ·of the Compardle, ~ piles were found out to be In oblo1ute perfect condition tNt 4t was even reused for pH• foundation.
Pile - is a structural member of small cross-sectional area with ·reasonable length driven down the ground by means of hammer or vibratory generator.
Pier- refers to a large cross-sectional dimension, each capable of transmitting the entire load from a single column down to a stable stratum. · Piles are classified according to: 1. Type and size 2. Shape as to the cross-section 3. Materials
As to the kind of materials:
1. Timber pile 2. Concrete pile 3. Metal pile
109
CHAMFERED
POINTED
SQUARE
TIMBER PILES WOOD PILE
Fig ure 6- 7 ·
6-9
THE IMPORTANT FUNCTIONS OR USES OF PILES
The decision to use pile foundation is the result of scientific method of exploration and tests of the underlying soil conducted by the designing Engineer which were brought about by any of the following purpose: 1. As friction pile at their bottom portions in transmit· ting the load through soft strata into stiffer lower strata. 2. As friction pile utilizing its full length. 3. As soil compactor. 4. As end-bearing columns 5. As stabiHzers of banks 6. As better piles 7. As a dolphin 8. As sheeting Unless batter piles are intended to be effective in serving any one of these functions, they should not be used, otherwise driving piles without any purpose will be an exercise in futi.lity.
110
Soft"'...,,.,
sOft
material
or soil "'bje(t to scour
.
Friction
load~rrying
material
friction
Rock
load-earrylnl
materiaf
A• End·Bearinc Columns
A$ Frl~:tlon Pile& ~r Poltlon\
A$ Friction Piles for Full length
In
looaa
mettfitl
As Stabilizers of Banks
As Soil
Compactor$
·,.
As Batter Piles, Fender Piles, Dolphin,, and Sheeting
Uses of pilea.
Figure 6- 8
111
6-10 QUALITY AND DURABILITY OF PILES Pile should be selected properly to possess a quality capable of resisting without damage to the following: 1. To resist crushing under vertical load 2. To resist crushing during the process of driving. Timber piles are not susceptible to withstand high stresses due to hard driving that requires a desirable penetration on a highly resistant layer. In driving piles, it is very important to select the right type of hammer and the number of blows to prevent breakage and create damage on the pile head, piles driven by steam hammer at 15,000 ft. pound (20,340 joules) energy should not exceed three to four blows per inch or 25 mm. to prevent breakage or brooming of the piles, the normal resistance of pile is from 6 to 8 blows per inch or 25 mm. which is normal and commonly specified. 3. To resist handling stresses. Timber piles should be capable of resisting breakage or other damages that may result from hand· ling, hauling and impact in loading or unloading. 4. To resist tension from uplift forces, heaving of soil or re· bound in the process of driving. Timber piles shall be strong enough to counteract the uplift forc~s and expansion of soil including the rebound action received in the process of driving. 5. To resist horizontal and eccentric forces that will cause bending when applied on it. 6. To resist curvature bending and column action for the portions not receiving lateral support from the ground when freely standing in air, water or a very liquid mud.
Pile Selection In selecting the use and types of piles the following factors are considered:
1. Availability of supply 8. Carrying capacity 2. Expected life span 9. Proximity of structure 3. Deterioration condition 10. Cost 4. Types of underground 5. Method of placing 6. Length of piles 7. Characteristic of structure and ,loading 112
Economic comparison should be based on the cost of the entire foundation instead on the cost of the pile alone.
6-11 TIMBER PILES Timber pile is not new in the field of construction. Vitruvius in his writing described the Roman builders to have been using timber piles in their foundation work as early as 58 A.D. It shows that even the early builders during the Roman Empire dispensation have recognized the importance of providing a structure with a strong foundation. The use of stone, bricks and· cemented slab footing have already been employed by the Egyptian, Romans, Babylonians and the Mayan and Yucatan builders. The discovery of cement by the Romans associated by the demand for a massive structures have prompted the early builders to study the nature and behavior of soil in carrying a massive load. It is during this stage that timber piles were introduced in making foundation. With the advent of power equipment used in building construction, pile driving would not be difficult as that of the Romans way of driving piles crudely through manpower.
TABLE 6- 2 WOOD PILE LENGTH AND DIAMETER Minimum Tip Diameter of Butt (em.) Length of Pile Diameter em Min. em Max em Under 12 meters 13m to 18m Over 18 meters
30 32 35
45 45
50
20 18 15
The diameter of the piles shall be measured in their peeled condition. When the piles is not exactly round, the average measurement may be used. The butt diameters for the same length of pile shall be uniform as possible. Piles shall be peeled removing atl the rough bark and at least 80% of the inner bark and no less than 80% of the surface on any circumference shall be cleaned wood. No strip of inner bark remaining on pile shall be over 2 em. wide and 20cm.long. All knots shall be trimmed close to tl'le body of ·the pile. 113
6- 12 DETERIORATION OF WOOD PILES
!J
Wood piles are subject to deterioration caused by decay, insect attack, marine borer attack, mechanical wear and fire. Timber piles are said to be durable when driven below the normal water level, on the otherhand, the life span of timber pile above water level even if treated with creosote under pressure will only last for a duration of about 40 years. Tirriber piles penetrated by salt water are subject to deterioration caused by marine organism called Teredo and limnoria. Wood piles under attack by marine borer maybe terminated within a few years under extreme favorable condition of which no amount of chemical treatment could cure in any manner.
6-13 PROTECTION OF TIMBER PILES: The methods of wood protect ion depends upon the local conditions, types of expected economic life of the structure, severity of service, e(!se of repairs, costs, etc. The two methods applied in eliminating or reducing wood attack are:
1. Poiso ning the wood by creosote through pressure treatment. 2. Mechanical protection. Untreated wood piles is capable of resisting decay indefinitely if d riven below the normal water table. CreosOte treatment protects the outer surface of wood through penetration of the chemical that ranges from 20 to 25 mm. Piles shall retain preservative in at least the amount given in the following table.
TABLE 6-3 MINIMUM PRESERVATION PER CUBIC METER OF WOOD Uses and Type General Use Marine Use
114
Type of Processing Empy Cell Process Full Cell Process
190 Kg.
320 Kg.
200 Kg.
350 Kg.
6- 14 PILE DRIVING Before driving piles, adequate knowledge and preparation had already been made such as. gathering of data, underground explorat ion and soil tests and the use of pile which were brought about by the result of the struct ural design. Driving of pi les involves some considerations which some of them are enumerated as follows: 1. The timber pile to be used shall be free from sharp, short or reverse be~d because crooked piles with sharp bend will only create trouble during t he process of driving. , 2. See to it that the taper of the pile shou ld be uniform from the butt to the tip. 3. The butt of the pile should be square or chamfered to fit in the pile cap. 4. The t ip of the pile is either pointed or squared. Pointed t ips sometimes cause the pile to drive out of vertical position that in most cases square tip is preferred. 5. Timber pile shall be driven by the right type of hammer because it cannot resist high stresses due to hard driving lthat is required to penetrate highly resistant layer of soil. Timber piles could not be driven against a very h igh soil resistance without damage and are rarely specified to receive driving load in excess of (30 tons) 298 kilonewton but usually restricted to (25 tons) 250 KN or less. The tip of the timber pile which could be easily damaged is protected by t he use of steel shoes, on the otherhand the butt is also provided with an ample protection by the use of cushion block. 6. Pile cushion should be attached at the hammer base in order to reduce the impact stresses and at the same instance prolong the life span of the hammer. The hammer is rat ed based upon the energy per blow where the rated energy is the product of the weight of the ram and the height of the fall less the friction energy loss on the ram guide. Driving hamm~r dif fers greatly in the manner in which they deliver energy to the anvil or hammer cushion. The ham111er cushion are of two different types, the soft and the hard type. The soft type is sometimes made of wood and asbestos which are very common although there are other types being developed. The hard type cushion contains alternating disks of aluminum and micarta which is considered to be efficient in its performance after
l15
several use while others which are of low quality such as wood chips or coiled steer cable are rarely specif ied . T he pile cushion elements does not only protect t he top of the pile as well as the hammer from t he high stresses but also deliver significant influence on the wave stresses that is being developed in the process of pile driving such as: a. b. c.
It affects the driving characteristics of the pile The depth to which it can be driven The load carrying capacity
The selection of the type and dimension of cushion block that. gives satisfactory result including the type of the hammer are of two categories: a. To assure a maximum driving force in the pile equal to the maximum capacity of the pile without overstressing the pile. b. As much as possible to transmit the maximum energy of the hammer to the pile. The lack of contro l an d selection .of the right cushioning materials which is usually recommended by the manufacturer in their catalogue of the types of cushion block for a certain driving hammer will permit a degree of subterfuge or escaping of the device t o avoid impact force. 7. Driving sequence of pile shall be given attention for it might affect the penetration of the pile into the ground. The central piles in a group shall not be left until the last has been driyen to a definite depth, o therwise, this might be dangerous to cause damages to th.e piles previously driven. 8. Driving piles near a reta ining wall should be given careful attention for it may cause displacement and damage t o the adjo in· ing struct ure due to the vibration of the soil. 9. Over driving indicates bending of piles, hammer bouncing, cutting of driving plate into the pile and separation of wood along the annual growth rings which causes head brooming. Careless driving procedure such as unusually hard compaction of the cushion, block tilting of the head cap, non axial blows and uneven pile head causes damage to the pile. The head failure due to impact of driving could be prevented by banding before drivi.ng. 116
'---A-1...:. PlL'E. DRIV\1-16
Figure 6 - 9 TABLE 6-4 PENETRATION RESISTANCE AND SOIL PROPERTIES BASED FROM THE STANDARD PENETRATION
TEST Clay Rather Unreliable
Sand Fairly Reliable Number .of blows per meter
0-12 12-30 30-90 90 - 150 over 150
R~lative
Density
Number of blows per meter
Very loose loose medium dense very dense
3 6-12 12-24 24-45 over 90
:Consistency very soft soft medium stiff hard
TABL£ 6-5 RANGE OF SKIN FRICTION FOR VARIOUS SOIL
1. Silt and soft mud ... .... . 2. . Silt compacted • • . . •....
3. Cl.ly and sand .. ••..•.... 4. Sand with some clay ••.. •. 5. Sand and Gravel . . . . .... .
240 to 480 kg.jsa.m . 580 to 1,700 kg.jsq. m. 2.440 to 4,880 kg./sq. m. 1,950 to 3,900 kg./sq. m. 2,930 to 4,880 kg./sq. m. 117
6 -: 15 CONCRETE AND PIPE PILES Concrete piles are class ified into two types:
1. Cast-in-place
2. Precast piles (prestressed)
a. cased b. uncased
CUed piles- is cast inside a metal shell form which are left in the ground.
Uncased piles - eliminate the metal casing or shell which invariably reduces the cost. The methods of construction are as follows: · 1. An open end pipe is driven into t he ground, clean it out then f ill the hole with concrete and finally, the pipe is withdrawn. 2. Heavy drive is dragged into the ground by dropping a hammer directly on plug of fresh concrete. The pipe is removed progressively as additional concrete mixture is rammed inside the pipe. 3. Pumping concrete under continous pressure through a hollow shaft of an auger, the hole is drilled by an auger which is then pulled out f rom the ground. Consequently concrete is then pumped into the shaft . 4. Pipe piles usua lly has a diameter of 25 t o 75 em. with a thickness t hat varies from 2.5 to 4.5 mm. _{)ti"" IMo.J
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6-16 PRECAST CONCRETE PILE Precast concrete piles are reinforced to resist high stresses · caused by the hammer in driving. Precast pile reduces tension cracking caused by handling and driving. This type of piles are ~ighly resistant to deterioration even when used above the normal water table. The presence of high concentration of magnesium or ~dium sulphate salts in the water may cause deterioration of the ieinforcement in the piles through cracks, or thin protective c;onrete covering. Covering will spall-off as rust continues to develop.
(a)
co
steel bonds welded to reinf.
. (b)
0
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COMMON
T 'fPE
USEO FOR
BRIDGE TR E. S TLES.
b) FUENTES PILE. e) 8RUMSPILE PRESTRESSED CONCRETE PROVIDED WITH ORIVING FIT OF STEEl.. HR·RULE.
Figure 6 - 11
6- 17 DETERIORATION OF CONCRETE PILES 1. Deterioration above the ground is caused by weather and air borne destructive elements. 2. Underground deterioration is not common unless water contains destructive alkali, acid or salt. Other destructive elements· may come from the chemical and industrial manufacturing plants. 3. Deterioration in sea water is caused by mechanical and chemical action 4. Damage due to handling and driving of the concrete pile. 5. Defects in the manufacture of concrete pile. ·
6-18 METAL PILE Metal is an excellent material for pile because of its strength character.istics to withstand hard driving and rapid penetration into the ground, relatively with small material displacements. The: 1 different metal piles used in building constructions are: 1 i
1. H-piles which are suitable in penetrating into rocks or any·. hard materials with ease in driving and least effect in time. ., 2. Box pile- is suitable materials for pile on sliding bank or 1\ in deep water. . 3. Rail piles - the railroad rails are used by welding 3 rails \ ~ogether at head and base to form a unit pile. i 1 I \
i
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I
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••=
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u
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Figure 6 -12
6-19 DRIVING EQUIPME.NT The. early builders in their way of driving piles used mauls, ratchet winch rams, treadmill drivers, water wheel drivers or gang operated rams. The first modern steam pile driving machine was invented and introduced by Nasmyth in 1845 designed as a drop I hammer for wood piles which was then modified into a handle I single acting hammer. At present, piles are driven into the ground I by means of a hammer or a vibratory generator. The hammer I t operates between a pair of parallel guide suspended from a standard i lifting crane. The bottom of the guides connected at the base of 1 the crane boom by means of a horizontal member called spotter. i The spotter is adjustable to permit a plumb position of driving i piles and the hammer is axially guided by steel rail which was 1 incorporated in the guides. 1
1
{ 120 1 I
TABLE 6-6 PROPERTIES OF SELECTED IMPACT PILE HAMMERS
Rated Energy Joules ft·lb
Make
Model
Stroke Weight Blows at Rated Striking Typea Per Energy Parts Minuteb (em.) (Kg.)
Vulcan MKTC MKT Vulcan Vulcan
2
s
983 1083 1
DB DB
20,340 20,475
7,260 8,750 13,100 15,000 15,100
21,696 24,679 25,967 26.442 26,442
16,000 18,200 19,150 19;500 19,500
MKT Link-Belt MKT Raymond Vulcan
DE-20 440 118 65C 06
30,374 30,510 33,052 33,086 33,154
22,400 22,500 24,375 24,400 24,450
MKT Delmag Vulcan Kobe Vulcan
OE-30 D-12 0 K13
soc
DE 45-60 OF 111
35,256 35,662 43,392 44,070 44,070
26,000 26,300 32,000 32,500 32,500
Vulcan Link-Belt MKT MKT Vulcan
08 520 OE-40
s 50 DE 80-84 DE 48
44,070 48,816 53,833 55,053 56,002
32,500 36,000 39,700 40,600 41,300
Raymond Vulcan Del mag Raymond Kobe
56,952 66,105
42,000 Vulcan 48,750. Vulcan
9,844 1,186
1,776
-----
50C
SlO 010 00 140C D-22 000 K-22 014 016
73 42 47 90 38
1,363 727 1,363 2,272
DE 48 DE 86-90 DE 95 OF 100-110 s 60
243 90 47 90
909 1,818 2,272 2,954 2.954
DE 48 DE 42-60
243 243 97 259 40
1,272 1,250 3,408 1,304 3,636
97
3,636 2.304 1,818
s
OF
s
s s
70 145 105 60 120
so
55 50
s
50 OF 103 DE 42-60 50 DE 45-60
s s s
60 60
40
110 243 97 97 97
2,272
4,545 4,545
259
4,545 6,363 5,681 2 204 2,204
90 90
6,363 7,385
38 97 243
S a • single-acting steam; DB= double acting steam; OF • differential Acting steam; DE= diesel. b = after development of significant driving resistance. c =for many-years known as McKiernan-Terry.
121
The different types of driving equipment are: 1. Drop hammer or impact hammer
2. Air or Steam hammer a. Single acting hammer b. Double acting hammer
3. Differential acting hammer 4. Diesel hammer
Drop Hammer - usually falling on the fresh concrete as in the installation of franki pile (Figure 6-10)
Air or su-n Hammer - operates by litting .a- ram by air or steam pressure then allowed to fall by gravity with or without the pressure of air or steam. If the fall is due to gravity alone the hammer is classified as Single Acting. If air or steam pressure supports the downward fall, the hammer is said to be DoW,Ie Acting or differential depending upon t he detail of the construction. DieseJ Hammer- are of two types: a. Open ended b. Closed ended
Open Ended Type - the ram falls by gravity and lifted by the explosion of fuel and compressed gas in the chamber between ~he bottom of the ram and tt:le anvil block at the housing base. Closed Ended Hammer - the housing forms a bounce chamber where air is compressed by the rising ram, the com· pressed air then acts as spring that control the rise of the ram and thereby shorten the stroke, the stored energy returns the ram to downward stroke. Too. high pressure will cause the hammer to jump off the pile, such behavior is known as racking which usually cause damage to the equipment. The weight of the ram including its height of' fall plus other informations regarding the different types of drivng equipment are shown on Table 6-6. 122
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Pit,.£ tVSMM* OP f 10trfAl.
a IIIIILI:• KTM ITUM
IJ 011••111010 DIIIIL M - ·
Figure 6- 13
TABLE 6- 7 CUSTOMARY RANGE OF WORKING LOADS IN DRIVING PILES
Type of Pile
. Load in tons 15-20
Timber 8 fnches or 20 em. tip diameter Concrete precast or prestressed 10 in. - 25 em. diameter 18 in.- 45 em. diameter
25 - 60. 60-200
Steel Pile or shell, concrete filled not mandril driven 10314" x .188 pipe 1()34" x .250 pipe 10¥4" X .250 p ipe
30'7 50 45 - 70 50-80
123/4' x .250 pipe 14 x .312 pipe. 16 x .375 pipe Steel H section HP lO .x 12 HP 12 X 53 HP .14 x 89 HP 14 X 117
60- 90 100-200 100-120 50- 70
so- ·go
100- 150 150-200 123
6-20 PILE SPACING The efficiency of the pile in serving the purpose for which it was intended should be maximized not only through proper selec· tion of the types and length, the correct type of driving hammer nor the right way of driving application but also the spacing which also plays an important role in the efficient performance of the pile in supporting superstructural load. ·
A. The effect of too close pile spacing are: 1. Creation of large horizontal pressures in driving particularly on a relatively uncompressible underground layer which sometimes cause damage to t he piles being. driven or that has already been driven. . 2. The carrying capacity of the soil where the group of piles acts may be less than the whole sum of the fractional capacities of the soil that encloses the individual piles if too closely spaced to each other.
B. The effect of wider spacing of piles:.
1. Wider spacing has the tendency of readily perm itting the latter piles in group to penetrate the same depth of the first pile which in effect gives uniform bearing and settlement. 2. Wider spacing of piles reduce heaving and tension damage including the possibility of crushing the outer surface of the piles. 3. The value of the group may be increased and the piles serves efficiently if spacing is increased. Piles intended to serve a marine structure which are exposed to receive wave action should be spaced at a min imum of 5 times its diameter apart to 'reduce countercurrent, whirlpool and abrasion.
6- 21 DRIVING OF PILES THROUGH AN OBSTRUCTION In case of obstruction met during the pile driving such as boulders, rocks or thin stone strata, an advance rod sounding jets or diamond drill rigs is advanced before driving wood piles.
124
Pilot pile is also used before driving timber or concrete pile, an beam, H pile or mandrell is used for this purpose. Spudding is also applied by raising and lowering the piles with heavy precast piles every after little driving progress. There are several methods applied in placing piles such as;
7. Washing O!-!t
1. By driving 2. Jetting
8. Sand pumping
9. Blowing out
3. Boring 4. Ramming 5. Jacking
11. Drilling
6. Pulling Down
12. Explosive
10. Coring
,:
6- 22 CAUSES OF PILE DEFLECTION IN DRIVING In the process of driving piles, deflection cannot be avoided which causes the pile to penetrate the soil out of plumb. Deflection of piles during the process of driving maybe brought about by the following: ' L Piles may glance-off to an obstruction or hit a scoping bed rocks. 2. In soft clay, piles tend to bend toward previously installed close-by piles due to the soil softening from remoulding during the driving . . 3. Bowing of the jet pipe caused by the weight of the hose that causes piles in jetting group to penetrate out of plumb. 4. The lower portion of a batter piles sometimes tend to sag and cau.ses curvature.
6- 23 SETTLEMENT OF FOUNDATION The different causes of settlement due to loads imposed on the soils are:
1. Soil bearing capacity failure including partial failure or creep. 2. Failure or deflection of the foundation structure. 3. Shear distortion of the soil 4. Compression of the soil. 125
Other factors that contribute to the settlement or movement of foundati.on are:
1. 2. 3. 4. 5. 6.
Subsidence due to mines or caves beneath the surface Subsidence due to underground erosion Landslide and creep of the underground Vibration and shock of loose cohesionless soils Lowering of the water table Soil shrinkage by dessication or exhaustion or increase of soli mixture 7. Lack of lateral support in excavations 8. Heave or swell - slow movement due to horizontal displacement of soil vein or stratum 9. Chemical Action·- this includes decay of materials The settlement caused by these factors are considered as indirectly related to the superstructure load imposed on the soil.
6-24 FAILURE OF PILE FOUNDATiON
.
.
The failure of the pile foundation may result from any of the following causes:
1. Lack of adequate boring 2. Inaccurate soil classification 3. Soft strata under tip of pile ~.
Inadequate driving formula (wrong data)
5. Improper size of hammer cause insufficient penetration, 6. 7. 8. 9. 10. 11.
12. 13. 14. 15. 16. 126
too light or damaged if too heavy Misinterpretation of load Damaged ofencased piles Buckling of piles Breaking of piles Vibration that cause'lateral or vertical movement Flowing strata caused by adjacent excavation or bank sloughing Tension failure of concrete pile for lack of reinforcement Eccentricity due to bowing or falling out of plumb Decay due to lower ground water level Insect and marine borer attack and corrosion Disintegration of concrete due to poor quality of concrete
or reactive aggregate 17. Collapse of the thin shell of the piles 18. Overweight due to earthfill.
REMEDIES: 1. Early repair such as encasement or replacement 2. Removal of partial load 3. Underpinning
6-25 GRILLAGE 'FOOTING The early attempt to increase the area of footings and to mini· mize the load was made possible through the introduction of grillage footing to replace the oldest way of building foundation by the use of masonry structure made out from various sizes of stones joined by mortar. With the advent of reinforced concrete at the early part of 1900, grillage footing became obsolete. Almost all constructions are now dominated by the use of the new materials.
JC Wf'
GRILLAGE fOOTING
Figure 6-14
12·7
CHAPTER
f
SOIL TEST UNDERGROUND EXPLORATION Foundation design is primarily based from the result of subsurface investigation. The Engineer who has to make the design must have a reasonably accurate conception of the physical pro-perties and arrangement of the underlaying soil. The most suitable method under a wide variety of soil conditions is by drilling a hole into the ground and extracting samples for identification or testing. The investigation of the underlaying materials as to its consistency or relative density of the deposit could be made by penetration test or other methods which do not require sampling.
7-1 AUGER BORING The simplest device for boring a hole in the ground is the Auger. The two varieties of hand auger commonly used for soil investigations are the helical auger and the I wan or post hole auger. A portable power driven helical augers are available from 8 to 30 em. oftenly used for making deeper holes.
.. IWAI&OR POST HOL£ AUG£R
Figure 7-1
7- 2 WASH BORING The methods applied in wash boring is to drive a piece of metal tube of 5 to 10 em. diameter to a depth of 1.50 to 3.00 m., 128
the tube or casing is cleared out by a chopping bit fastened to the lower portion of the wash pipe inserted inside the tube or casing. Water is forced down through the wash pipe by means of a high velocity pump to rinse the fragments of soil through the annular space between the tube and the wash pipe. This method is similar to the process of installing an underground water pump where the · pipe is cleaned by wash pipe and water.
7- 3 HOLLOW STEM.AUGER BORING A truck mounted driving rigs turn the auger into the soil rapidly to a depth of more than 60 meters using continuous flights of auger with hollow stem where sampling tools are operated. Auger with 6 or 8 em. diameter are commonly used.
t~EF'
II.I.IGER SMAFT SAhiPLEIIt
\LEGS OF PIPE
ROD
2
HOLLOW- STERN AUGER I PLI!O WHilE ADVANCING AUGER.2 PLU"0 !SAMPLE~~ ltiSER1ED i'O GET SAio'Pt.E Of SOIL.
Figure 7- 2
CHOPPH4G BIT REPL ACEO BY SAMPLING SPOON
WASH 80RtN G
F1gure 7- 3
7-4 ROTARY DRILliNG Is the most rapid method for penetrating highly resistant materials such as rocks, clay or even sand. The rotary boring diameter ranges from 5 em. to 20 em. (2 to 8 inches).
1.29
t4rf4f'
::.~:~~.}!~~,.~
Fiqure 7- 4
7- 5 PERCUSSION DRILLING Percussion drilling is sometimes called cable tool drilling used when wash boring or auger boring could not penetrate exceptionally hard strata of soil or rocks.
7- 6 PENETROMETER
A device used to investigate and measure the consistency of cohesive deposit or relative density of cohesionless strata without the necessity of drilling and getting samples. If the penetrometer is pushed steady into the soil, the procedure is called Static penetra· tion test, when driven into the soil it is called Dynamic Penetration Test. Static Penetration test is preferred for cohesive soil while Dynamic penetration test is good for very hard deposits. Both give satisfactory result for cohesionless soil. Standard penetration test is the most widely used in the United States; it is done by dropping a 60 kg. hammer into a drill rod from a height of . 70 m., the number of blows to make a penetration of 30 em. is regarded as the penetration resistance.
7- 7 DUTCH CONE PENETRATION A 600 cone with a base area of 10 sq. em. is attached to the bottom of a rod protected by a casing, at a rate of 2 em. per second, the cone is pushed by the rod into the ground, the cone is slightly. larger than the pipe to minimize friction. Another method 130
of soil testing by means of a cone penetrometer is by driving a drop hammer into the ground with constant height of fall, the number of blows per 30 em. penetration of the point is con· tinuously recorded and when the point reaches its final depth. the pipe is withdrawn and the cone is left at the bottom of the hole. The dutch cone penetration test is the most rapid and eco· nomical method being adopted recently. R~o tASIN(i
Figure 7-5 COIIt
7- 8 VANE SHEAR TEST The vane aparatus for shear testing clay soils in place consist of four vertical rectangular blades bolted at right angles to a ver~ tical shaft. The vane is pushed into the soil and then twisted until the soil is ruptured in a cylindrical form, shear strength is computed from the maximum moment needed to rapture the soil and the dimension of the soil cylinder.
Figure 7-6 131
7- 9 STANDARD LOAD TEST The Building Code on load test so provides: "Where the bearing capacity of the soil is not definitely known or is in question, the Building Official may require load tests or other adequate proof as to the permissible safe bearing capacity, at that particular location. To determine the safe bearing capacity of the soil, It maybe tested by loading an area not less than .18 sq. m. (2 square ft.) to not less than twice the maximum bearing capacity desired for use. Such load shall be sustained by the soil until no a(jdltional settlement takes place for a period of not less than 48 hours in order that such desired bearing. capacity may be used. Examination of sub-soil conditions may be required when deemed necessary." The load test procedures will be as follows:
1. Dug to the dep1 r of soi'l to be tested usually the proposed footing level. · 2. . The pit width should be at least 5 times the plate width. 3. The square plate with a general d.imension of .30 x .60 m is set on a levelled bottom of the pit. 4. Place the load on top of the plate by a platform loaded with concrete blocks, cement or jacking with a calibrated hydraulic jack against a beam properly anchored down the earth. 5. Measure the settlement by the level instrument or by a micrometer dial gage mounted on a support independent of the loading system. 6. Apply the load to an increment of about one tenth the estimated failure load· or the proposed design load until complete bearing capacity failure or twice the design load is reached.
f
7. Each · increment is maintained constant which settlement readings are made at regu lar but increasing interval such .as 1, 2, 5, 10, 20, 40, and 80 minutes. · 8. The load test result express only the short term loading of the model and not necessarily the long term loading of a full sized footing. Extrapolation is necessary in order to be able to use the data for design. The results found in the load test requi re careful interpretation for it may in some instances be· misleading specially if the subsoil
132
is not uniform for a considerable depth below the base of t.he proposed foundation.
Figure 7·· 7 In determining the dimension required for a foundation, it is the designers responsibility and duty to ascertain first the allowable bearing capacity of the soil. The local Building Code authorities should be consulted of the allowable bearing capacities to be adopted in design. In the absence of such information, boring or load test is necessary. Table 7·1 is presented for reference purposes. TABLE 7- 1 ALLOWABLE BEARING CAPACITY OF VARIOUS SOILS Underground classification A.lluvial soil Sof clay Firm Clay Wet sand Sand and Clay mixed Firm Dry sand Coarse dry sand Gravel Gravel & sand well cemented Hardpan or Hard shale Medium Rock Rock under Caisons Hard Rock
Kg. per sq.m.
pounds per sq. ft.
ton per sq. ft.
kilopascal! k Pa
4,891 9,782 19,564 19,564 19,564 29,345 39,128 58,690
1.000 2,000 4,000 4,000 4,000 6,000 8,000 12,0001
1k 1
4 6
54 107 215 215 215 322 430 644
78,256 97,818 195,636 244,545 782,545
16,000 20,000 40,000 50,000 160.000
8 10 20 25 80
860 1,073 2,146 2,681 8,580
2 2 2 3
133
CHAPTER
8
POST AND COLUMN 8-1 DEFINITION
Post"" Refers to a piece of timber of either cylindrical, square or other geometrical cross section placed vertically to support a building; a compression vertical member not continuous from story to story is also called post. Column = Refers to a vertical structure used to support a building made of stone, concrete, steel or the combination of the above materials.
Story = Is the space in a building between floor levels or between a floor and a roof above. 8- 2 WOODEN POST Unlike other parts of the building that could be easily replacea, wooden post shall be selected out from the best quality of lumber under the classification of the first or second group for strength and durability. Treated lumber is also used as wooden post in the absence of hardwood lumber. Wood post are erected in the following manner:
1. After dressing the wood post, the bottom portion is evenly cut with the atd of the steel square. A charcoal or chalk mark is established along the face length of the post connecting the opposite end. This marking will serve as the reference line for checking its vertical position. 3. From the bottom of the post, indicate -the distance where the girder and girts will be attached and make the necessary dap before its erection. 4. The post could be erected manually with the aid of 2 x 3 lumber braces or by the use of rope and pulley anchored on a jump-pole. 5. Check the vertical position of the post on two sides by the aid of plumb-bob. Have it braced on four sides and ~ail the wooden post temporarily to the post strap.
2.
134
6. With the use of boring tools. dril1 a hole across the two straps and have it bolted to its per~anent positions.
-
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ol EltlCTION OF WOOO POST
bl CORRECTING TNE 8E ND
POST
Figure 8-1 TABLE 8- 1 DIMENSION OF WOODEN POSTS OR SUPORTALES Maximum Types of Building Height of 1st Floor
1 storey shed 1 storey shed 1 storey shed 1 storey house or chalet 2 storey house or 2 storey house 2 storey house 2 storey house
l.OOm 3~00m
4.50m 5.00m
Maximum Maximum Required Maximum Height Spacing Finished Size of Total (m) of Post (m) Suportales
4.00 3.00 5.00
3.50 4.00 4.00
10 X lOcm · lOx lOcm 12.5 x 12.5 em
5.50 6.00 7.00 8.00 .9.00
3.60 3.00 4.00 4.50 4.50
12.5 x 12.5 em 12.5 x 12.5 em 12.0 x 15.0 em 17.5 x 17.5 em 20.0 x 20.0 em '11i:
Logs or tree trunk supportales may be utilized as post in its indigenous traditional type of construction, provided, that they are of the sizes and spacing capable to sustain vertical loading equivalent to the loading capacity of the posts and spacing as provided for on Table 8-1.
COMMENTS: Bent post could be corrected in the process of construction, but no att6mpt should be made to correct the bent unless proper bracing and adequate support be made first, otherwise, the foundation pedestal might break-up during the operation. The usual failure of this nature is the crushing of the pedestal brought about by the twisting of the wrought iron post strap. · At present, the trend is to avoid the use of wooden post in building construction under the following considerations: 1. Reinforced concrete column appears to be cheaper and durable.than the wood post. 2. Commercial lumber nowadays are taken from young trees thereby producing inferior quality of lumber. 3. Hardwood is scarce and could hardly be found in big lumber or sawmills. · 4. The cracks between the wooden post and the concrete wall is inevitable aside from its prominence on the wall · finished. 5. Wooden post is susceptible to decay brought about by moisture insect, worms, termites and the like.
8- 3 REINFORCED CONCRETE COLUMN Reinforced concrete is at preseRt the most popular and widely used materials for column of buildings instead of wooden post regardless of its size or height. Reinforced concrete columns are classified as: 1. Short Column = When the unsupported height is not greater than ten times the shortest lateral dimension of the cross sect ion. 2. long Column = When the unsupported height is more than ten times the shortest lateral dimension of the cross section. 136
Columns are classified according to the types of reinforcement used: 1. 2. 3. 4. 5.
Tied Column Spiral Column Composite Column Combined Column Lally Column
!--Lateral t1es
Tied Column
Spiral Column
Composite Column Combined Column
Figure 8 ·.2
8- 4 TIED COLUMN T.ied column· has reinforcement consisting of vertical or longitudinal bars held in position by lateral reinforcement called lateral ties. The vertical. reinforcement shall consist of at least 4 bars with a manimum diameter of No.5 or 16 mm steel bars. Lateral ties= The ACI Code so provides: "All non-prestressed bars for tied column shall be enclosed by lateral ties of at least No. 3 in size for lon9.itudinal bars No. 10 or smaller and at least No. 4 in size for No. 11, 14 and 18 and bundled longitudinal bars. The spacing of the ties shall not exceed 16 longitudinal bar diameter, 48 tie bar diameter or the least dimension of the column". The Code is specific that 13/8") or 10 mm diameter steel bar shall be used as lateral ties for a column reinforced with 32 mm or smaller longitudinal bars. Likewise, 12 mm steel bar shall be used as lateral ties for column with longitudinal reinforc'3ment having a diameter from 36 to 57 mm including those longitudinal bundled bars. 137·
The spacing of the lateral ties of a tied column is governed by three factors: 1. Should not be more than 16 times the diameter of the longitudinal or main reinforcing bar. 2. Should not be more than 48 times the diameter of the lateral ties. 3. Not more than the shortest dimension (side) of the column. To find the spacing of lateral ties required for a tied column, the following illustration is presented: Hlustration: Determine the spacing of the lateral ties for a tied column as shown on Figure 8 - 3.
~.20"""~
0 -
-lG,.m
.fO
'"'·
IQ.,..rn ...J
---IDN•m
\
Figure 8-3
Solution: a.
The diameter of the longitudinal bar is (3/4"1 or 20 mm The diameter of the lateral ties is (3/8") or 10 mm b. Multiply: 16 x 20 mm =32 cm · c. Multiply: 48 x 10 mm ::= 48 em d. The shortest side of column =30 em From the result·of the above computation, it could be readily seen that the least value found Is 30 em. therefore, the spacing of the lateral ties will be af 30 centimeters on center. When there are more than 4· vertical bars in a tied column, additional ties shaU be provided in order to hold the longitudinal bars firmly to its designed position. The Code further states: "the ties shall be so arranged that every corner and the alternate longitudinal bar shall have lateral support provided by the corner of the tie having an inclined angle of not more than 135 degrees and no bar shall be farther apart than 15 em clear on either side from such a laterally supported bar." 138
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111 ACI Coot .
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Figure 8-4 Rein~ement Ratio 1nd Limitation =The size and number of steel bars be plac,ed in a tied co lumn is governed by the proportion of its cross sectional area to the gross area of the column.
to
"The cross sectional area of the vertical reinforcement shall not be less than .01 nor more than .08 times the gross area of the column section. ••
Illustration: Find the .mm1mum and maximum steel bats that could be placed in a tied column having a cross sectional dimension of (10" x 12") or 25 x 30 em.
. ,. D
. -...
~ I{) · 29 Mt'l"'l
-- ~·\C.mm .
MINIMUM REINFORCHIIEI/T
Figure 8-5
Solution: A -
Minimwn Reinforcement: a. Solvo for the cross sectional area of the column, 25 x 30 = 750 sq em (10" x 12""' 120 sq in) 139
b.
Solve for the minimum area of the vertical reinforcement. .01 x 750 = 7.5 sq. em. {.01 x 120 = 1.2 sq. in.) c. Convert this area to the size and number of steel bars by the aid of Table 5 -I. 9 Area of 4 pes. No. 5 (16 mm) bar = 8.04 sq. em. (Area of 4 pes No. 5 (5/8") bar = 1.24 sq . in.
8
Maxim lilt Reinforcement: a. .08 x 750 = 60 sq. em. (.08 x 120 = 9.6 sq. in.) b.
(English) Metric:
Table 5-2 shows that: 10 pes No. 9 bars gross area= 10.0 sq. in 8 pes. No. 10 bars gross area= 10.12 sq. in. 10 pes. 28 mm gross area = 61.6 sq. em. 8 pes. 32 mm grons area = 64.3 sq. em.
From the result of the above illustration, it appears that the minimum steel bars that could be placed in a 25 x 30 em. column are 4 pes 16 mm steel bars. Likewise, the maximum reinforcing bars that could be placed therein are ei't her 10 pes 28 mm or 8 pes 32 mm diameter. The above example shows how to determine the least and the most number of bars that could be placed in a tied column. Bundled Bars - Difficulties had been encountered in placing concrete inside the forms congested with steel bars. A column that is heavily loaded with reinforcement has this serious problem when large nu mber of steel bars are positioned and held indiv idually by lateral t ies. Bundled bars are sometimes employed consisting of 2 to 4 bars tied in direct contact with each other to serve or act as one unit reinforcement placed at the corner of the lateral ties.
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Figure 8 · 6
140
~
18
16
- --
H
12
25 29
196 224 252 280
432
468
24 26
396
288 320 352 384
256
308
41
46 51 65 60
37 41 45 49
83
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192
168
25
23
216 240
324 360
22
20
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20
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115
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131 H7 164 180 197
158
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86
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58 63
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49
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207 230 253 276 300
164 184 206 225 246
L25
143 161 179 197
92 108 123 138 154
115
00
102
+ 1000
156 168
143
117
130
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115
92 104
111
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91
71 81
86
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130 144 158 173
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113
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219
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132 151 170 189 208
146 162
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ALLOWABLE LOAD ON A TIED COLUMN
' · - 16,000
18 22
144
18
18 20 22 24
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16 18 20 22
14
12 14 16 18 20
180
120 140 160
16 18
a
12
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Colultlll Size
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230
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29.2 3.24 356 389
346
317
288
.259
176 202 2'Z7 252 27'7
130 151 173 194 2111
1112
108 1211
1«
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84
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61
66 80
120
77 98
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81 10! 130 160
61
32
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24
84
612
401
624 682
346
373
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10
163 .200
128
101
56 77
40
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195
164
lin 121
118
.a
280
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142
66
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25&
18
230 .293 360
71 101 138 1M .202 256 326 400
154
113
79
87
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223 282 368
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174 190
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loU 158
178 187
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1110
198
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868
828
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277
2~7
238
218
~
216
64
81 100
.51
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160
122
Q6
58 711
42
80
3S6
110 112
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640
624
B~
16
676
691 780
620 608
423 file
4541 481
454
88D 421
336 418
366 893
aa7
. 863
311
3011 333
878
327
:161 285
8.51
270
207 824
am
281
2111 238 259
18
200
163
128
101
40 66 77
203 260
120
• 1150
70
00
60
15.3 192 244 300
115
8S
99
848
2.15
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134 177
ee
256
m m
IM 202
79 ll3
-
366 449
227 288
8lll
127 173
1lail or Bard G.-.de: /o - 20,000
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41
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222
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8 10
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205 260
182
63 00
113
160
185
125
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116
108
100 108
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99
92
77 84
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77 83
M 70
LOAD ON BARS
Grade: / o - 16,000
l2
Number of &r.
TABLE 8-3
128
100 116 181 148
87 ga
811
319
205
74 80
79
203 815
248 270
287
226 :u6 2M
205
73
tiS
82
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8
1000
184 900
1024 1156
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81 67 72
61
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4
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82
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80
J8 28
676 728
67e 824 672
24 218
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24
20 28
628
484
22
26
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480 620 6GO
24
20 lt2
28 80
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810
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320 407 49\l
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20
900
922 1040
706
666
6011
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664
47.5 ·~ 615
482 468 $06
39e
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100
22
Allowable Load on a Tied Column - All parts of building structures are. designed to carry load or resist forces classified ac· cording the manner how it was designed. Tied column design could either be under designed, over designed or standard designed which connotes unsafe, costly or safe respectively. The design of a column shall be sufficiently strong to carry a super imposed load which is referred to as the allowable load.
to
These tables are presented with the end view that it could be of help in some ways to the reader in determining or checking the column size and the steel bars required to support a given load. The use of these tables will shorten the time and lessen the efforts to be exerted _on the mathematical processes involved using various formula. The special features offered by the tables are: 1. How to determine the size of the tied column and the quantity of the steel ban required to carry a given load. 2. To check the strength of a tied column if its size and rein· forcements are either adequate, less or excessive to what is needed. The principal consideration involved in the design of structure are: cost and strength. The term cost is academic and easily under· stood because anything that involves money be it in the form of income or expenses is everyone's concern and it is where human interest comes in. · Failure of tied Column -Tied column failure is by crushing and shearing outward along an enclined plane where vertical bars fail by buckling outward between lateral ties. The failure of a tied column is said to be abrupt and complete and is considered to be more disastrous than the failure of a single beam or girder in the same floor.
PAII.UR! 01' A
T If D COLIIIIIN
Figure 8-7
The design of a structure should be strong and safe to both life and property but economical in the sense that the sizes and materials specif ied are just enough to resist all kinds of stresses imposed on it. In using these tables, the following illustrations are presented.
PROBLEM: Determine the size of a tied column having an unsupported length of 9 feet and the reinforcement required to support an axial load of lOO,OQO pounds (100 kips) with the following specifications: . F'c = 3,000 psi Fs = 20,000 psi
SOLUTION: 1. Assume a column size, say 10" x 12'' having· a cross sectionai area of 120 sq. inches. 2. Referring to Table 8-2, the load carried by the concrete under the column F'c 3,000 is 65 kips. 3. Substract: 100 kips less 65 kips= 35 kips. 35 kips is the excess load to be carried by the concrete, which is then to be carried by the steel bars. With the aid of Table 8-3, 4. Under the column of Fs = 20,000 psi, 19 kips and 77 kips are 1he values of minimum and maximum load of bars that are allowed on a 10" x 12" cross sectional dimension of tied column. 5. It will be noted that since 35 kips fall within the limit of 19 and 77 kips, the assumed column size is acceptable. 6. Referring to Table 8-3 under the column of Fs 20,000 psi it shows that: a. 4 pes. No. 7 bars could support 38 kips or b .. 8 pes No. 5 bars could support 40 kips Either of these arrangement will be acceptable being slightly greater than 35 kips. However, the limitation for bar spacing as explained in. Chapter 3 shall be observed. In this particular case, values found on (b) is preferred. I
1.44
Figure 8-8
Con~ion to Metric MaaiUre = Table 8-2 and 8-3 were reproduced from ACI Reinforced Concrete Design Handbook. Values are of the old English measure including the computation of the example problem. The valtAes from the table together with the illustration could be easily converted to the new Sl system of measure with the aid of the conversion factor presented below. Consequently, it was not changed abruptly - specially at this time of transition from English to Metric system because, it would be difficult for one to adjust if the figures were completely changed with a new one he Is not so familiar with.
'Problem : Convert to Metric equivalent the values on Table 8·2 and 8-3 as used in the illustration presented and the result with the aid of the following conversion factor :
Multiply
by
pounds per square inch (psi) x 0.704 pounds per square inch (psi) x 6.895 pounds of force x 4.448 pounds x .4545 .inch X 2.54 kips x 454.5
to get kg.jsquare em. kilopascals newtons kilograms (kg.) centimeters kilograms 145
Construction Method of 1 Tied Column: There are three methods presented in the construction of a tied column for a small and medium reinforced concrete construction.
1. Block laying of walls after the concreting of the columns 2. Concreting of the column before the block laying of the walls. 3. Simultaneous concreting of the columns and walls. Tied column vertical reinforcements are anchored on the footing by means of steel dowels tied to the footing reinforcements or, the main reinforcements Itself attached to the footing reinforcement followed by the pouring of concrete. Sometimes the concreting of the footing is simultaneous with the pouring of the column, depending upon the specifications and methods being adopted by the Engineer or construction supervisor. The construction of a tied column under the first method of "block laying after the concreting of the column" shall be as follows:
. Step 1 = construct the scaffoldings that will support the column reinforcement to its vertical position. Usually there are 4 pes. of lumber vertically installed around the column provided by horizontal braces spaced at 1.00 m elevation. Step 2 = lransfer the markings and reference line of the build· ing from the batter board to the lower and upper horizontal member of the scaffolding. Check the vertical projection of these markings by the use of the plumb bob. Step 3 = .Provide a temporary horizontal wood brace above and below the scaffolding inserting it across the reinforcement to hold the bars to its vertical position. The idea of inserting the brace across the reinforcement is to give way to the installation of the column forms. Step 4 = Ascertain the vertical position of the reinforcement in the row of several column In both directions, then install the small sides of the forms in opposite direction and insure its vertical position.
1.46
Figure8-9
=
Step 5 Do not cover the forms until after the following accessories have been verified from the plan and installed if there is:
a. Downspout b. Electrical conduit & utility boxe~ c. Standpipe or fire hydrant d. Plu.mbing and water line e. Telephone line f. Burglar alarm line g. Intercom and door bell I ine h. Steel dowels for wall doors etc. Step 6 = In the final covering of the forms. see to it that the wider cover is provided with charcoal mark and nails to serve as guide in ascertaining the column size and in fixing the form to its vertical position. Remove all dirt and debris before closing the form. Step 7 = Do not leave the column forms until it is firmly set and completely supported. Most of the bulging failure of forms are due to negligence and the inherited manana attitude. Step 8 = Before concreting have the work inspected by the authorized inspector or supervisors. Usually this is done before the closing of the forms giving the inspector the access to see the sizes and arrangement of the reinforcing bars. The construction of columns under the second condition of
"Concreting the Columns after the Blod< Laying of the Walls" are as follows:
=
Step 1 The wall footing construction includes the installation of the vertical reinforcement of the wall. Block laying follows immediately the concreting of the wall footing to save cement mortar. Step 2 = The space altoted for the column reinforcement is left vacant in the process of block laying. Step 3 = Install the pipes for downspout, conduits, utility boxes and others.
=
Step 4 Clear the column space with sawdust, earth, dlrts, debris and wash thoroughly before installing the column forms. Step 5 = Install the forms enclosing the column reinforcement, check the allignment and vertical position, have it properly braced or cross-tied with galvanized wire or machine bolts then pouring of concrete mixture could follow.
Figure8-10 Comments:
COitCitiT•••
01'
c:o1.11•"
'""Ill 1\.0c:ll
LAYIU
1. This type of construction requires only two pieces of forms to cover each column, the, reinforcement being flanked on two sides by the hollow block walls. 2. The bond between the wall and the column will be strong. er, unlike when it was connected by mortar in the process of block laying. Cracks between this joint will be unlikely to appear on the surface. 148
3. Horizontal bars used in the block laying were laid conti· nuous across the column reinforcement. This process minimizes the horizontal overlapping splices and consequently, eliminate the use of horizontal dowels supposed to be inserted across the column in preparation for the wall construction if column con· creting is ahead of the block laying. 4. The columns will not be much affected by shocks or vibrations caused by removing the forms because the column is laterally supported by the hollow block walls. Likewise, the work is easy, fast and economical less the destruction of the forms, lumber braces, waste of nails and labor aside from the handy handling of transferring and re-installing of the forms. 5. Not all columns fall under this condition, because there are also independent columns that are free from the wall layout of which the previous methods discussed shall apply. The methods of construction under the third condition of simultaneous pouring of column and walls in one setting of mixing. could only be made possible if the concrete mixture for both columns and walls are of the same proportions. On the other hand, if the proportion of concrete differs from one another, one must be ahead of the other and it is preferred to give the column such priority which in effect the method falls under the first condition.
8- 5 SPIRAL COLUMN - Spiral column is the term given where a circular concrete core is enclosed by spirals with vertical or longitudinal bars. The vertical reinforcement is provided with evenly spaced continuous spiral held firmly in position by at least three vertial bar spacers. The column reinforcement is also protected by a concrete covering cast monolithically with the core. Comparatively, this type of column is stronger than the tied column and is preferred for a slender (long) column in carrying heavy load. When .a load is imposed on a cylindrical column, a lateral pressure is exerted at the confining materials which eventually causes hoop tension in the spiral, a closely spaced spiral confining the concrete and vertical bars counteracts the lateral expansion while the concrete in the core increases its carrying capacity: The sign of failure of a spiral column is advanced by the shell (protective covering} spall off due to excessive load, but failure of the column occurs only when the spirals yield or burst. Unlike the tied 149
column that fails abruptly, the spiral column with heavy spirals shows a gradual and ductile failure.
-=.:::::.··
~ .
~
3
~........Spiral-
.':'== e
J: ,,-....,..........._._
Figure 8-11 Spiral Reinforcement Umltatlon and Spacing = For cast in place construction, spiral reinforcement shall have a minimum diameter of 10 mm. and that the dear spacing between the spirals shall not be more than 7.5 em. or less than 2.5 em. The longitudinal reinforcement area to the gross column area shall not be less than .01 nor more than .08 and that the minimum number of vertical bars shall not be less than 6 pes. of 16 mm bar diameter. *Section 7.12.2 of the ACI Building Code specifies "Spiral reinforcement for compression members shall consist of evenly spaced continuous spiral held flrm~y in place and true to line by vertical spacers. At least two spacers shall be used for spirals less than .50 m. diameter, three for spirals .50 to .75 meter in diameter and four spirals for more than .75 m diameter. When bigger size of .steel bar is used for spiral such as 16 mm or larger, three spacers shall be used for a spiral having .60 m or less in diameter and four spacers to a spiral having more than .60 m diameter .•. The spirals shall be protected from distortion due to h.andling and placing from the designed dimension." *note: conversion of measures from English to Metric were supplied. Spiral Anchorage and Splicing= ..The anchorage of spiral reinforcement shall be provided by one and a half extra turn of spiral bar or wire at each end of the spiral unit. When splicers are necessary for special bars it shall be tension lap splices with 48 bar diameters as minimum but in no case shall be less than 30 em. or weld. l.SO
The reinforcing spiral shalt extend from the floor level in any story or from the top of the footing to the level of the lowe.st horizontal reinforcement in the slab, drop panel or beam above. Where beams or brackets are not present on all sides of the column, ties shall extend above the terminal of the spiral to the bottom of the slab or drop panel. In a column with a capital, the spiral shall extend to a plane at which the diameter or width of the capital is twice that of the column."
Problem: Determine the size of a short spiral column and the steel reinforcement required to carry an axial load of 200,000 pounds when fc = 3,000 psi; fs "" 20,000 psi using cold drawn wire for t~e spiral reinforcement and there will be - 1112 inches concrete protection.
. Solution: 1. Assume a circular column say 15 inches diameter . 2. The column load is 200,000 pounds or 200 kips.
3. Table 8-4 under round columns; load on concrete fc = 3,000 shows that a 15 inches diameter concrete carries 119 kips_ 4. Subtracting 119 from 200 k ips, the excess load on concrete is= 81 kips to be carried by the steel bars. 5. Referring to Table 8-4 the load on bars under fs = 20,000 psi are 35 kips minimum and 187 kips maximum since the excess load is 81 k ips which falls between the minimum and maximum value, the assumed column size of 15 inches is acceptable. ' 6. Referring to Table 8-5 under "Rail or Hard Rail" fs == 20,000 psi, seven pieces of No. 7 bars carries 84 kips load. 7. Table 8-6 .. shows that 11 inches core diameter column could accomodate 8 pieces No. 7 steel bars; therefore, the 7 pieces of No. 7 found on step 6 is satisfactory. 8. Referring to Table 8-7 under ·•cold drawn 1 1/2., concrete protect ion" and 15 inches column size; 3/8" spiral shatl be spaced at 2 inches pitch. 15 t
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Mm. Mn Mln. Mf.K .
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SPIRAL COlUMNS. LOAD OH GROSS SECTION
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4.61 490
6481811 1181 11M
ao.
238
259 281
14& 1&2 180
116
130
101
o..=r~,
TABLE 8- 4 8quano
Ban
t5 11 68
• M
12 80 88 97 106
116 126
135 14& 157
188 192 206
:us
1.-1
1.-to.ooo
OD
lAM
1.- ts.ooo
31
68
52
ce
3a ·&1
xt.. x!a. ..... M1... ~ .....
-71
cu.
441
361 4.00
21
18 Ill 20
'I? 86
484 92
100 108 117 12&
185
1n
1M
tu 374 180
S41
154
1088
1024
!.lOO
,.,;;t
,Sf
~~
ne
626
629
12 28
578 i
I
!
I
k 26
ao
2e 27 28 .29 SJ
12 88
from Rart/rwutl. CoJOCrCt• Dui~rt H..Ubo<>l:,
V'l
C"o1
-
-
"'w
68
11 f8
· -
1$2
1fn
fll
72 95 ~
63
~-
218
178
HO
Ill
IH
43 62
711 108 142 180 229 281
70
116 128 HIO 203 250
56
liO
200
22$
183
163
Z79 3-t3
25.1 812
200
132 174 220
97
68
120 168
112 88
275
224
126 160
114 144
128
203 260
116
71 101
67
66
17 106 139 176
70
-
37-l
74 106 144 190 240 305
300
192 244
162
00 M 115
1101111121
60
9
45
I
63 86
8
40 56
I
86 411
7
88 112 IU 175
I
371
Ill 110
18
15 16 11
fll
122 lliO
116
16
42
fll f lO
30
f/j
6
te
8iae
B.r
- --
805 314
240
1110
381 468
300
237
182 180
113
- -
356 481
280
221
f¥1
156
4.06
74
106 144
711
liQ&
826
258
154 202
113
424
146
163 215 272
84 120
88
«II
866
2811
228
127 178
I 99
499
406
320
263
192
HI
432 631
340
269
204.
lli()
105
562
360 457
5113
380 483
300
223
118
167
112
158 216 284
240 304 3811 414
182
114
IN
llG
Rail or Hard Grade: 1. - 20,000
28& kll
224
lM 177
69 99
205 2M 830
l1a
Intetmediat. Grade: I.- UI,OOO
Ia• lu It& In
123 168
IH
81
a:u·
2M
208
126 164
92
M
18
Number ol Ban
ZI
624
508
316 400
240
124 176
lOt
66.'1
634
~20
252 332
130 185
624
U"T
JM
14.1 2lln
.. 400
320
m
•
1U 19%
20
440 569 686
264 848
194
138
549
IOD LIS 211 278 &52 447
488
467
718
384
364 460
276
143 202
67~
149
740
480 610
379
211 288
ne
811
520 G60
411
112
229
161
640
521
329
260
Ul8
129
- - -
305 600 685 780
300
15.5 220
824
400 508
m
316 ~1
384
240
124 176
303
230
111 1811 368
1Q 221
·u•
I I 1211Z812~juJH
(Mai . ..t • - 0.08A1)
SPIRAl COLUMNS. LOADS ON lARS
r-d on Bart, A. {kipe) •/..&0 + 1000
TABLE 8- 5
S.r SiH
15
Ring
0 I
0
10 10 $
11
7
u 11
•
1a
12
9
u
u 1 tf 10 • 11
.
d:~o(Core
22
21
28
29
26
21
26
:10
81 26
24 1$
23
18
24
17
23
30 25
26
18
1':'
29 24
23
27 23
19
22
21
18
26 21
25 20
22 1T
13
21 16
u,
20
26 21
24
2!
.23
24
22
HI 15
,_
Manmum Number of S.ra io Out.~: ~line. 0, aod in 11111« RiDe. I
10 8
~~~"
TABLE 8- 6
9 4
7
7
9
$
4
7
6
8
10 6
11 7
9 5
5
9
7
9
9 4
\)
7
6
9
11 7
9
14 10
13
12
9
11
-
11
14 10
7
12
11
13 tl
14
13 7
13
HI II 1---
17
10
14
11
13
6
18
-
11 6
6
li
6
11
--
10
·
9
10
-
IS
20
13
7
9
17 12
-
lll 14
18
20 IS
17
16 ll
14
16
8
9
15
--
14 9
7
16
9
19 lli
c-.u DuiiJI Ha~.
22
20 16
16
14 9
16 10
19 13
21 17
;ao
--
27
12
27 :.!2
;--
20
211
18 12
H
16
22
20
24
18
12
15
ll3
Ill
20
11
18
14
16 11
20
17
- --0 a II 16 18 19 21 25 16 21 28 u 19 1 1 8 14 18 "u --- --17---- - - - - -0 8 to u 16 18 21 23 l a 9 12 17 18 19 -- - 0- - - -- - - -- - - ,_ -- 22 13 18 8 15 18 18 I 8 8 9 13 19 - - - --1 - ---- - - ------ ---- - - - - -0 6 8 10 18 21 19 15 17 I 6 8 9 10 12 13 - - - - --. - -s f--- 10- - - - - ·- 12 ----- -- - -f, ,0 8 19 8 13 15 17 17 18 19 I 12 13 13 7 8 8 10 u 12 - - - - -- 1- ----- -7- · 8- - - --!-:--- - u - ·- ----------,11 12 12 13 14 17
~_I~ =
AmMican Concrete l.o.atitute {rom Rftrt/tNUtl
lot\
-.
CJt
Ut
1t
12
13
14 15 18 17
18 19
14
16
18
17 18
21
22
23
2'
.2$
27
aa
10 Sl 32
lit
•
21
25
ao
20
26 26 · Z7 28
20
22 23 24
IQ :.0
Diameter
I Con
Slae
Coh•mn
K-2
H-2K H-2
H-2~
:K--2J.1 K-2K K-2J.1
}i-2J.S H- 2J.S K-2J.S .J.S-2)(
u-zu u--zu
•
H-2~
~2)(
u-zu
)f-2"
H-2 ~, ~-2 }! H-2 }~
H-2J.S
H-2J.S Ji-2J.S J.S-2J.S
~-2J.S
Jt-2" H-2"'
~-2U Ji-2~
~2J.S
Jt-23(
~-.2
~2
I
3750
I
5000
2000
• • •
• • •
,.,...2
~-2
H-2 H-2
,.,...2
H-2 H-2
Uo-2)(
~-2.1-t
Jt-2~
u-zu
•
Uo-2 J+-2
•
•..
•
•
•
• • •
• • • • • •
•
•
•
•
•
H-3 Jr3
~
H-3
J+-3
~
H-3
~3
~3
K-3
~
H-2J.1
Jf-2)(
u-zu
H-2~
H-2)(
~2)(
)f-2)(
H-2)( Jf-2)( *2K H-214:
H-2~
)f-2)(
~
' )f-2)( K-2)( Jt-2U Jt-2!{
u-2
~I"
~2
2300
H-3
K-2U K-2J.S Jf-2"'
~%)(
~2
~·"'
~2
Hot-Rollecl 1 :K-In. Cooeret.e ~n
3ooo
H-2U
I
Jt-2U
Jt-2"
,....2"'
H-2"'
U-3
~
}i-2 :K--2 .li--2 .li--2 K-2
K-2
Ji-2
H-2"'
Jf-2!{ Jf-2!{
•
Ji-2 }i-2
2500
u-zu
'i-2 !{ Ji-2J.S
}i-2 }i-2
•
2000
I
COLUMNS. $IZ! AND PITCH Of SNAl$
Sq U&('l ColuiZl.ll I 1-~---,--~---1·
TABLE 8 - 7 SPII~.L
I
K-2 '
)f-2·
*2 )f-2
K-2 H-2 H-2
H-2
~2 ~2
H-2 )f-2 ,.,...2
~·"' K-2 H-2
K-l"'
~·"'
~~"'
*•"'
3000
H-2"
)t-2J( .J.S-2"
K-2"' K-2"' )f-2"'
H-2"'
K-2U K-2"'
J+-2)( Ji-2J.S J+-2H K-2U
••
Ji-2 }i-2
8760
~
Ji-.2"
u-2"
. H-2"
·I
RoiUI
Ji-2)( Ji-23( Ji-2)(
. J.S-2 H-2 H-2U
}f-2
.H-2
H-2 K-1 )f-2 . )f-2 K-2
Ji-2 Jf-2
H-1 H-2 K-2
•• )f-S
11000
16
12 13
10 11
I
Colwnn Core !De Diam9ter
11 17 1. 16
14
11
~ •
3750
_
I ~60 I
Jlouad Column
l_&m
K-2~
K-2
~2
••
~2
)f-2
~2
••
*2X
~2~
~~
~2
••
&000
*"2~
K-2 K-2 *"2
~2
K-2 ~-2
-'T-2
~~"
~~" ~~" ~-l"
*"2~
*"2H
~~
~X
H-1~
~"
~-sx
~"
H-2U H-2H Ji-2)i H-2H K-2H *2H
~23i Jf-2~
~)i
K-2~
~~~ K-2~
Jf-.2~
K-2~
••
)f-2~
).f-2
..
~2~
)f-2
••
)f-2~
•• ••
K-23i
••
Jf-1~
-'i-2 Ji-2
)f-2
Jf-1"
*"2~
~~ ~~ K-1~
K-2 K-2
H-1"
K-2~
JT--3~
~2~
~2"
~~
H-3}(
J+-aX
K-SX K-SX
K-2" K-2" )i--2"
"'""'"
).f-2~
H-2 K-2
~X K--3~
K-2"
~2X
Ji-2)( K-2~
Jof-2X ~~~
H-1"
H-2~ H-2~
~1~
Hot-Rolled 2-In. Conttete l'lol.ection
. •
• • • •
••
• • • • •• •
• • • •
•
• • •
• • • • • • •
•
• • • • • • • •
•
~2
I_~ _I 2~
SPIRAl COLUMNS. SIZE AND PITCH Of SPIRALS (CCNtfillueJ) Square Column
••
K-2~
Ji-2~ ~2X ~2~ -'T-2~
*2
~2
I~ I~ I I~
• K-2 K-2
•
~~
•
K-1 K-2~ ~2~
~2~
~2~
-'T-2
*2" ~2~
~2
~2K ~~K
~2~
UJ . 17
K-2 K-2
21
li :10
19
18
~2
K-2
K-2 K-2 K-2 H-2
••
K-2
~2~
~HU
K-2U K-2K H-2X Jf-2X K-IX K-2X
K-2
-'i-2~
K-2
K-23i
~~ ~~
10
u
~~
23
22
25
29
28
26 'Z1
H--3 H-3 K-2U K-2"
K-2 K-1
:n
22
aa u
26
rr
ll6
28 29 80
31 83 33
on
-o
.....
Ul
u.
16
17 11
28
80
11
38
u
a
26 27
2$
ao
~
u
22 23
II
11 11 110
17
21
27
2G
~
u
2S
22
21
~
1&
lit
13
15
t•
11
12
u
H-3;(
*'"
H--3.!i ).f-3;(
u-su u-.au
,U-2
K-2 Jt-2 H-2 H-2 Ji-2 H-2
K-2;( H-23( K-2;( Ji-2.14
K-19( Jt-2 K-2
*2" K-2" H-2" Jt-2" H-2U )f-2U K-2U
U·2;(
H-3
H-3
H-3
Ji-1" H-1"
Ji-1;(
H-l"
,.....,.
H-1"
Jt-19( K-1" Jt-19(
H-2 ).f-2
H--2.14 H-2;( Ji-2;( Jt-2;( Uo-2;(
*-2U *-2U .K-2U 3f-2U ).f-2;(
H-2U
K-2.K K-2.K Ji-2"
*-2~
•
JT-:1 *-2
Ji-2)i
'*2" H-2"
2U
:t.2"
Ji-2J(
~
~
).f-2 H-2 K-2 ).f-2 K-2
).f-2;( ).f-2,!i K-2 ).f-2
•
JT-2 K-2
H-3-;(
u-su
)f-3;(
K-2
;(-2 ;(-2 ;(-2
H-3!1: "'"'*" H-3;(
H--3;(
~;(
H-3;( Ji-a;(
~
Jt-a;(
,......
ft-2"
K-2;( Ji-2U K-2U
K-19( K-2 K-2
""'2 Ji-2
K-2 ;(-2 ;(-2
;(-2
K-2 ;(-2 3(-2 ;(-2
~-2
U-1" J(-2 ,!i-2 }(-2
;(-1"
;(-19( ;(-1"
Jt-2 ,...2 H-2
*2" Ji-2
*2" Ji-2;(
Ji-2;( H-2;(
Ji-2;(
K-2.K
Jf-2;( Jt-2.K H-2.K Ji-2.K
•
K-2 K-2
Oold·Drawn I H-~- Coacrete Protectioo
u-a
""'H-33
H-3
H-3
Jt-a
"'"'""''** H-3
~ ~ ~ ~
K-2U Jt-2U Ji-2J(
H-2~
~2
Jt-19( K-2
"'"'"
H-SK
Jt-2;( K-2;( Ji-2.)(
u-au JHK
H--IU }S-3;(
H-3;( H--3;(
)of-a;(
H-3.14
J+-3.14
H-1" .K-3.14
K-1"
H-1"
Ji-1" K-1" Jt-1"
~lj(
Ji-lj( Jf-IJ(
H--2~ .
)f-2;( H-2}( H-2.14
'f-2;( 'f-2;( H-2J(
ft-2;(
K-2K
~2;(
Jf-2.14 Jf-2,!i Ji-2.!i
K-lJ( K-2 H-2
Ul CD
13
10 11 12
14
17
16 16 14 16 17
15
18 21 18 19 20
10 20
~
22 33 24
21 22
•
Cold-Dra•"Yl 2-ln. Cone~t. Proteetion
•
• •
•
•
•
•
•
~1"
~2
~2
'f-2 'f-2 Jt--2 'f-2
• • • •
• • • • •
•
H---2~
••
J+-2X
)f-2 J.t-2
H---2~
J.i--2)4
H---2)(
J.t-2 J.t-2
••
~2
)+-2 ~
H---2~
J.f-2"
~-2 ~
'f-2 'f-2 'f-2 *2
u-zu
J.i-2)4
J.i-3
'f--3
H-23\
~-2
~J4 ~)4
u-au
J.t-3 V.
~2)4
~2U
J.t-2~
J.i-2)4
'f--3)4
"'-21{ Jf-2 X
~-2 ~
~-2~
H-2}(
~-2 1{
~-8~
Jt--2"'
J.i-3}(
~-2
J.t-3J4 J.t-3J4
H-23i H-23i J+-23i H-2V.
*-2
'f-2 *2 'f-2 1{
u-ax
~2~
\' "''-'-2"' -2"' "'-2 '-'-2v.
'f-2~
"'~~" "2
.. .. ••..
~2
"'"2
~~"
'f-2~
"'"2)4
~2~ ~~
'f-2~ ~-2~ 'f-2~
JT-3
'f-3)4
'f-2~
'f-3 )4
~-3 U ~-3}1
- H-3~
H-•H
~3}(
'f-a3i
~-3)4
"'-3 J4
~2"'
~-a x
Jt--3
u-z"
~2~
•• ~·" ~2
~2
* 2
J.t-2
~-2
~2
~2
J.t-2
Ji-2~
Ji-2~
*2X *"21{ 'f-23i
~-2~
'f-2"' *2"'
'f-2~ 'f-2~ u-z~
*2"'
u-2~
u-z~
Jt--2~
*2
'f-IH
~~"
J.i--2 J.t-2
"'"2 !4
u-zJ4
J.f-2U
J.i-2 'f-3 'f-3 JT-3
"'Ji-2" "2"
*2
~2)4
J.f-2~
u-zu ~2~ J.t-2~
J.i-2)4 J.f-23\ J.i-2
~~"
"'~·" "1" 'f-1"
~2
J.i-2~ J.f-2~ J.f-2~
~-2
)f-1"
J.i--2 ~
J.i-2
*3
J.t-2 ;,.
J.t-2
J.t-3
'f-1" 'f-IH
)+-2 )4
23 )i-8
"'-3
24
26 27
28
J.t-2U J.t-ll~ ~2V.
J.f-2}(
"'-2 J4
'f--3
26
26
29
27 28
J.i-2H H-2H J.i-2" J.t-2"
29
32
30 31
88
Ex«eise Probl.-n: Solve the above problem as illustrated in Metric Measure {SI) using the following conversion factor:
by
Multiply psi psi pounds pounds of force inch kips
X
)( )( X
)( X
0.704 6.895 .4545 4.448 2.54 454.5
to get kg/cm 2 kPa kg. N em kg.
*Note: for more conversion factor see appendices. The preparation of the spiral reinforcement is very much dif· ferent from that of the tied column reinforcement because the former requires the skill and technique of making the spiral in accurate measurement to a required diameter. It is suggested that the spiral are bent continuously around a circular pattern disregarding momentarily the pitch. The spiral will just be adjusted to the specified distance or pitch by stretching the spring gradually upward during the tying or assembling stage.
8- 6 COMPOSITE COLUMN Composite column is another type of column where structural steel column is embedded into the concrete core of a spiral column. The work involved under this type of column is similar to that of a spiral column after the structural steel have been set to its position.
8- 7 COMBINED COLUMN A column with structural steel encased in concrete of at least 7 em. thick reinforced with wire mess surrounding the column at a distance of 3 centimeters inside the outer surface of the concrete covering. 159
<.\\
IT
-·
~.
Figure 8-12
COMS\JilEtl COLUMN
Figure 8-13
The construction processes of a combined cofumn calls for the installation of the structural steel as the main reinforcement, followed by the attachment of the wire mess covering. The wire mess serves as the holder ribs of the encased concrete. Usually the wire mess is attached to the structural steel by weld. The form makes no different with that of the previous methods discussed for tied and spiral column. 160
8- 8 LALLY COLUMN lafly column is a fabricated post made of steel pipe provided with a plain flat steel bars or plate which hold a girder, girts or beam. The steel pipe is sometimes filled with grout ·o r concrete for additional strength and protection from rust or corrosion.
IJI)HM--
B•am
-eo\t J/61Jli-- W·I · S-tr41p
,.....J:~~i!:J,.t:~l!.ese 'P14lte
'f'ootin.9
Figure 8-14
161
CHAPTER
9
PLATFORM- FLOOR STRUCTURE 9- 1 WOOD FLOOR SYSTEM Floor framing rs that platform structure of the building suspended by posts, columns, walls and beams. Wood, being the basic construction materials, with the development of machineries and sawmills advanced the knowledge and methods of construction that skeleton frame type was introduced taking full advantages of the different sizes of lumber that could be interchangeably made into framing purposes . The design of a platform - floor system depends upon the following considerations: 1. Live Load 3. Types of materials to be used 2. Dead Load 4. Sizes of the structural members.
5. Spacing of the structural members 6. Span of the supports. Live Load - Refers to those movable loads imposed on the floor such as people, furniture and the like. . Dead Load - Refers to the static load such as the weight of the construction materials which generally carry the live toad. Types of Materials to be used- The choice from the various construction materials available such as lumber, concrete, steel etc. The sizes and spacing of the structwal members depends upon its strength and capability to carry the load at a certain spacing. Span of the supports- pertains to the distances between the posts, columns or supporting walls~ The platform-floor framing structure is classified into the following types: a) The Plank and beam floor type b) The panefized - floor system c) The conventional floor framing system.
162
•) I'LAMI( en .. 8f:AN
Figure 9 -1 ~
.
Among the three different types of floor framing system, the conventional type is the most popular and widely used because of economy, simplicity and ease of work. The different parts of a platform floor system are:
1. 2. 3. 4.
Girder 6. Trimmer Sill 7. Tail Beam Floor Joists 8. Ledger Strip Bridging 9. Draftstop Plate 5. Header 1 0. Floor'ing Girder: -Is a principal beam extending from wall-to wall of a building supporting the floor joists or floor beams. Others define girders as the major horizontal support members upon which the floor system is laid. Girders may either be:. a) Solid b) Built-up 163
....
_
.... _
Figure 9-2 Sill: - That part of the side of a house that rests horizontally upon the foundation . Sill is further defined as those wood mem~ bers fastened with anchor bolts to the foundation walls.
Floor Joists: -Are those parts of the _floor system placed on the girders where the floor boards are fastened. Joists are usually nailed on the girders at a distance from 30 to 35 em. on center rigidly secured by bridging to prevent from wagging sideways.
Figure 9 - 4
Tail ben, Ledger strip, Dr.tbtop Plate
Figure 9-5 164
Header end Trimmer: - Header is a short transverse j oist that supports the end of the cut·off joist at a stair well hole.Trimmer is a supporting joist which carries an end portion of a header.
Figure 9-6 Flooring: - The Tongue and Groove wh ich are popu larly known as T & -G is generally specif ied for wood f looring. The T & G board thickness is either t t \ 2 em. or (1") 2.5 em. w ith varying width. that ranges from 7 em. to 15 em. {3 - 6") and the length from (8. to 20') 2.50 to 6.00 m. long.
Figure 9-7
"REINFORCED CONCRETE FLOOR SYSTEM:"
9 - 2 BEAM Beam is a structural member that supports the t ransverse load which usually rest on supports at its end. Girder - is the term appl ied t o a beam that supports one or more smaller beam. Beams are clasified as: a} Simple Beam b) Continuous Beam c) Sem i-Conti nuous Beam 165
Simple Beam: Refers to the beam having a single span supported at its end without a restraint at the support. Simple beam is sometimes called as simply supported beam. Restraint means a rigid connection or anchorage at the support. Continuous Beam:- Is a term applied to a beam that r&st on more than two supports. lltettrolnt
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Semi-Continous Beam: - Refers to a beam with two spans with or without restraint at the two extreme ends. ':~:.':::;··
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Figure 9-9 Cantilever Beam:- Is supported on one end and t he other end projecting 'beyond the support or wall.
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Figure 9 -10 T - Beam: -.When floor slabs and beams. are' poured simul. taneously producing a monolithic structure where the portion of the slab at both sides Of the beam serves as flanges of the T-Beam. The beam below the slab serves as the web member and is some· tim~ called stem. 166
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BASIS 01' TORTIONAL SECTION PROPER'tiES AND TYPIC A\. 1\E INI'ORCEMENT
Figure 9 ·11
Shear: - Is the effect of external forces that acts upon the structure causi_ng the adjacent sections of a member to slip at each · other. Strength- Is the cohesive power of the materials that resist an attempt to pull it apart in the direction of its fiber. Ultimate Strength:- Is the maximum unit of stress developed at any time before rupture. Moment:- Is the tendency of a force to cause rotations about a certain point or axis. , Strain: ~ Is a kind of alteration or deformation produced by the stresses. Stress: - Is an internal action set up between the adjacent molecule of the body when acted upon by forces. or combination of forces, which produces strain. Stress refers to the pressure of load, weight and some other adverse forces or influences. 9-3 RELATION BETWEEN THE MATERIALS AND STRUC· TURE Building structure has to be distinguished from building ma· terials. The combination of different building materi.als that make it into' a building part is called building structure. The building material in its raw form or unit has nothing to do with the strength or participation in supporting nor resisting the load unless utilized to be a member of the structure. The utilization of the different materials in the structure has their own purpose ot service in counteracting the different forces affecting the structure. ' 167
Thaf is where design comes in to determine their sizes, quan· tity, quality, spacing, proportions, mixture etc. Although the subjer.t matter in dealing with stresses, moments, compression torsion and the like are beyond the scope of this subject, it Is considered important to discuss the topicbrieflyto orient the reader and the beginner builders of the rudimentary knowledge on how these terms influence the principle of designing structure. Likewise, the reacting b'ehaviour of the structure when different forces are applied on it are relevant in the knowledge of building construction. · The DIFFERENT KINOS OF STRESSES THAT MAY ACT ON THE STRUCTURE ARE:
1. 2. 3. 4.
Compressive stresses Tension (Tensile) Stress Shear Stress and Strain Torsional Stress and Strain
Figure 9-12 Stresses on structures are usually brought about by load whictr are classified into three categories: a) Dead Load:Dead LOads are those loads that are distributed or concentrated, which are fixed in position throughout the lifetime of the structure such as the weight of the structure itself.
168
The dead load on a beam are also categorized Into two:
1. Concentrated Load 2. Distributed Load b) Live Load: ·• Live toad refers to the occupancy load which is either partially or fully in place or may not be present at all.
c) Environmental Load:Environmental load consist of wind pressure and suctions, earthquake loads rainwater on flat roof, snow and forces caused by temperature differentials.
Figure 9-13
9-4 BEHAVIOR Of BEAM UNDER THE INFLUENCE OF . . LOAD A homogeneous concrete beam even if free from carrying live or concentrated loads has to carry its own weight classified as a distributed load. The gravitational effect of its own weight will cause the structure to sag or bend downward between its support as shown on the following illustrations:
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Bending Moment: - Moment is the tendency of a force to cause rotation about a certain point or axis. Bending moment are · of two different types. the Positive bending and the Negative bending. The positive bending exists when the beam bends down· ward between its supports where the upper portion of a beam . above the neutral axis is compressed while the lower portion is stretched at the opposite directions. The Negative bending mo· ments exist when the beam is bending above the supports com· pressing the lower part of the beam below the neutral axis and stretching the upper portion of the structure.
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Figure 9· 15
9- 5 REINFORCEMENT OF CONCRETE BEAM It could be clearly seen from the behavior of concrete beam under the influence of load that the structure reacts correspondingly with the kind of interacting forces applied on it such as, the positive and negative bending which may cause its failure or collapse. It is under this principle that concrete beam has to be provided with reinforcement in order to prevent rupture of the fibers under stress. 170
1...om;r ~::te as a homogeneous material is said to be strong in supporting compression load but weak in resisting tension forces. Steel on the otherhand, possesses the strength qual ity to resist both compression and tension forces. The combination of concrete and steel producing "Reinforced Concrete" offers the solution to the problem. The principle behind the design of reinforced concrete is to avail of the strength of concrete in its capacity to carry the compression load and the steel to resist tension loads or ·• forces. When the area of the concrete and steel are just enough to carry the compression and tension forces simultaneously, the design is ca lled "Balance Reinforcement or Balance Beam". The .building Cod e on balanced reinforcement so prov ides that · the cross sectional area of steel reinforcement shall be equal to .005 times the cross sectional product of the w idth and the depth of the beam. Thus -
"Find the cross sectional area of steel bars required for a beam having a cross sectional dimension of 25 x 40 em. in order t o be considered .as a balanced beam. .
As
=
=
.005 X 25 5 sq. em
X
40
This is the minimum required area of steel bars in a 25 x 40 conc·r et e beam to be considered as "Balanced Beam"
Figure 9· 16 .. , ·
9 - 6 THE COMPRESSION AND TENSION
IN A BEAM
From Figure 9-15 the depth of the beam is divided at the center by a horizontal line called the Neutral Axis (NA). The portion above the axis at the support or column is under tension while the lower part is under compression.
171
Likewise, the lower portion of the beam that tends to bend downward between the support is under tension while the upper part is ·under compression. With the principle that concrete is to carry the compression load while the steel is to resist the tension forces, steel bars are placed in the portion of the beam where tension stresses developed. For positive bending the steel bars are placed at the lower portion of the beam. Whereas, in those areas where negative moment occurs the reinforcements are placed on the upper portion. To do these, there are two methods that may be employed. ·
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1. Bent Reinforcing Bars: Reinforcing bars are bent up on or near the inflection points and are extended at the top of the beam across the support towards the adjacent span. lnfltction points refers to the porticm of a beam where bending moment changes from positive to negative. This is usually located at a distance of about to t length of beam from the face of the support.
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2. No Bent Ban: -When bars are not bent, an additional straight reinforcing bars are placed on the top of the beam across the supports extended to the required length usually a distance about i the beam span length from the face of the support, other straight additional bars are also placed at the bottom center of the beam span where positive moment deveJops. 17~
Under the first method, the advantage of the bend bars is its function to resist the diagonal tension and shear which are usually counteracted by the stirrups or web reinforcement. On the other hand, the second method offers ease in the fabrication and install· ation of reinforcing bars unlike the former that inconvenience are usually encountered in the fabrication of bent bars and the diffi~ culties of repair when cut or bent Incorrectly.
9-7 SPACING OF REINFORCING BARS IN BEAM: Reinforcing bars are. placed accurately and properly secured in position with the use of concrete or metal chairs, spacers, or bolsters. If the beam design calls for a bent up bars, it is desirable to use an even number of bars for the main reinforcement. The idea is when other bars are bent at the inflection points of span, there will be remaining straight bars at the bottom continued at the supports where stirrups are tied up to their designed positions. The minimum clear distance between the main reinforcing bars should not be less than (1"} 2.5 em. nor less than 1 1 times the maximum size of the gravel.
TABLE 9 -1 MAXIMUM NUMBER AND SIZES OF BARS IN BEAM
2-*11 3-*9 4-*6
3-'*11 4-f9 . 5-'*6 . 6-..4
Figure 9-18 173
The measurement given under this table has considered the allowance of 4 em. ( llk"} protective covering of steel bars from outside of the reinforcement on both sides of the beam including the allowance for 10 mm ( i ) stirrups. The table also shows the maximum sizes of bars for ct given beam width. When two or more layers are required. the dear distance between layers of bars shall not be less than 3 em. placing the uppper layer directly above those at the bot~om layer.
9- 8 SPLICING, HOOKS AND BENDS The ACI Code on splicing, hooks and bends of reinforcement states, "Splice of reinforcement shall be made only as required or permitted on the design drawing or in the specifications or as authorized by the Engineer".
1. Lap splices shall not be used for bars larger than No. 11 or
35 mm bars ( ll
p).
. 2. Lap splices of bundled bars shall. be based on the lap splice length required for individual bars of the same size as the bar spliced and such individual splicing within the bundle shall not overlap each other. 3. Welded splices er other positive connection may be used. A full welded splice is one in which the bars are butted and welded to develop tension or compression of at least 125 per cent of th:e specified yield strength of the bars. 4. If the splices of joints under maximum stress could not be avoided. it should be staggered. Hook and bend refers to "Standard Hook" accomplished by a semicircular plus an extension of at least four bar diameters but not less than (2lfz") 6.5 em. at the free end of the bar or a 90 degrees turn plus an extension of at least 12 bar diameters at the free end of the bar. The maximum IJend diameter (other than strirrups and tie hooks} should not be less than the value given on Table 5·7. Stirrups and hook bend shall not be less than 4 em. for No. 3 bars; 5 em. for No. 4 bars and 6.5 em. for No. 5 bars.
174
Bars shall be bent cold, unless otherwise permitted by the Engineer. No bars partially embeoded in concrete shall be field bend, except as shown on the plans, ~pecif ied or permitted by the Engineer.
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J ______ , ,Figure 9-19
9-9 STEEL BARS CUT OFF AND BEND POINT It is a common practice to cut off bars where they are no longer required to resist tension stresses or in the case of a continuous beam to bend-up some of the bottom steel bars usually at 45 degrees to provide tension reinforcement at. the top of the beam over the supports. The ACI code so provides; ;;Every bar should be continued at least a distance equal to the. effective depth of the beam or 12 bar diameter which ever is larger beyond the point at which it is theorftically no longer required to resist streS$. The Code further states: uAt least 1 of the positive moment steeel 7' in conti-. nuous span must be continued uninterrupted along the same face of the beam with a distance of at least (6") 15 em into the supports. At least l of the total reinforcement provided for nega· tive moment at the suppor~ must be extended beyond the ex· treme position of the point of inflection, with a distance not /eS$ .than of the clear span or depth of the beam or 12 bar diameter whichever is greater. "
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9- 10 BEAMS REINFORCED FOR COMPRESSION When Architectural conditions limit the cross sectional di~ mension of the beam, it might be possible that the area of the concrete that will resist the comJ'ression load becomes smaller · and insufficient. Under this situat•on, steel reinforcement is substituted in place of the concrete area deficiency to supple· ment the ~oncrete in counteracting compression stresses. This type of beam is called .. Double Reinforced Beam" where stirrups or ties are used to hold the reinforcement together in position spaced not further apart than 16 times bar diameter or 48 tie diameter. · If compression bars are used in a flexural member, care should be exercised to ensure these bars from buckling outward spalling off the outer concrete when under load. The reinforcing bars should be properly anchored in the same manner as the compressive bar·s in column are anchored by lateral ties. Such ties must be used throughout the distance where the compression reinforcement is required.
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9- 11 WEB REINFORCEMENT Web reinforcement Is the same as the strirrups used in the beam to hold the reinforcement in its designed position. The web reinforcement is not only intended to hold the reinforcement and provide lateral support but also serves to resist- diagonal tension and counteract the shear action on the structure. The vertical stirrups should encircle the main reinforcement and hook bent w ith a diameter not less than 5 times the diameter of the stirrups at its end and secured prop.e rly to prevent slipping of the main reinforcement in·i he ~oncrete.
U-stirrups
Closed stirrups Figure 9-22
9- 12 TORSION IN REINFORCED CONCRETE MEMBER To resist torsion, the structure must consist of longitudinal reinforcing bars provided with closely spaced stirrups. The UStrirrups commonly used for transverse shear reinforcement are not suitable for torsional reinforcement, instead, a lateral ties used in column is being employed as stirrups which is effective In counteracting torsional stresses. Good anchorage is by hooking the stirrups bar end around the longitudinal or main reinforcement. If flanges of a T·Beam are included in the computation of torsional strength, a supplementary slab reinforcement should be provided. The main reinforcement should be well-distributed around the perimeter of the cross-section to control cracking. Spacing must not exceed (12") 30 em apart. Bars should not be less than No. 3 in size and at least one bar must be placed in each corner of the stirrups.
177
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Figure 9-23
9- 13 T-BEAM DESIGN & LIMITATION The ACI Code on T·Beam design specifies that:
1. The effective flange width shall not exceed {. the span length of the beam. 2. The overhang width on either side of the web shall not · exceeed 8 times the thickness of the slab or 112 the clear distance of the next beam. 3. For beams with only one flange at the side, the effective overhang flange width shall not exceed ! of the span length of the beam or 6 times the th ickness of the slab or! the dear distance to the next beam. 4. The principal reinforcement in the slab (T·Beam flange) is parallel with the beam; transverse reinforcement is necessary for the slab. The reinforcement spacing shall not exc'eed 5 times the thickness of the slab nor (18") 45 em. This is not applicable to a rib in a ribbed f loor construction.
9- 14 OTHER CAUSES OF BEAM FAILURE: The fail ure of a beam is not only due to shear, the positive or negative ~nding which was alreadyexplained but also includes bond. Failure in bond means the slipping of the steel bar rein.· forcement inside the concrete when load is applied on the struct· ure. lt is due to this problem that deformed steel bars were manu· factured in order to give a strong bond or contact between the steel and concrete. 178
COMMENTS AND OBSERVATION The use of a relatively high or low strength concrete or steel depends upon the cost, availability of materials, importlf1ct of special · requirements such as minimum sizes of the members structure and concern for deflection and crack width~ High strength concrete is attained by increasing the amount of cement in a mixture. Cement nowadays is considered expensive aside from several ingredient to be mixed such as, sand and gravel which in some areas, prices are so high and prohibitive that the cost of concrete increases substantially with the desire. to attain high strength concrete. On the otherhand, high strength steel are produced either metallurgically or by cold working available at a slight increase of cost. The present trend of building construction is to use reinforcements having an increased strength of (60,000 psi) 413,700 kilopascal while concrete on the otherhand will not likely change from the present allowable strength of (3,000 psi to 5,000 psi) 20,680 to 34,4 75 kPa. Consequently. labor plays an im· portant role in the cost of the building construction wherein the work for ·concreting should be compared with the cost of the work for the fabrication and instailation of steel bars. Records show that concreting including its preparation cost is substantially h igher than that of steel construction.
9 -15
REINFORCED CONCRETE SLAB:
Reinforced concrete floor slabs are classified into the following types:
1. One way solid slab and beam 2. Two-way. solid slab beam 3. Ribbed floors 4. Flat slab or girderless floors solid or ribbed Each type of the floor system has its own advan·tages in appl i· cation depending upon the following factors:
1. Spacing of the columns 2. The magnitude. of the loads to be supported 3. Length of the span 4. The cost of the construction
\79
One way sllb: - One way slab is the common type of reinforced concrete floor system made of solid slab supported by two parallel beams. The floor slab is known as one way solid slab, because the reinforcements runs only at one direction, that is from beam to beam. The one way slab is comparatively economical for a medium and heavy live loads on short spans ranging from 2.00 to 3.50 meters long. Although the reinforcement is said to be running in one direction, additional reinforcements are also placed in the slab parallel with the beams perpendicular -with the main reinforcements called "temperature. reinforcement". Usually No. 3 steel bar is used to counteract the effect of shrinkage and changes in temperature. It also distributes possible concentration of loads over a larger area. Unlike beams and girders, floor slab needs no web reinforcement or stirrups. In the case of heavy load where the shearing stresses maybe greater than the allowable values, the depth of the stab is increased.
Plan
One way s!ab reinforcement Figure 9-24 TABLE 9-2
MINIMUM SLAB THICKNESS
Simply supported One End continuous Both Ends Continuous Cantilever
180
1/ 1/ 1/ 1/
20
24 28 10
Illustration; A fully continuous slab is supported by a beam spaced at 12' or 3.60 meters. Determine the minimum thickness of the slab. Solution:
(English) 1,2 ft. = 144 inches t = .1M_= 5 inches 28
Figure 9 -25' Metric Sl: Span of the slab = 360 em. t = 3..6.0.. = 12.8 em. 28
Temperature and Shrinkage Reinforcement: - One way floor and roof slab are reinforced for shrinkage and temperature bars installed at right angle with the main reinforcements. The Code so provides; "that in no case shall these reinforcements be plaCed
farther apart than 5 times the slab thickness or more than 18" or
45cm. Table 9-3 SHRINKAGE AND TEMPERATURE REINFORCE·
'
MENT
Mintmum Ratio of Retnforcement Areas to Concrete Areas Slabs where plain bars are used ....... . ........ 0.0025 Slabs where deformed bars are used ....... ... : . 0.0020 Slabs where wire fabric is used having welded intersections not farther apart in the direction of stress than 30 em. . ..... . .. ...•.•..•.... 0.0018 In using this table, the following illustration is presented: 181
Problem: . A concrete floor slab having a thickness of (4") lO·cm. is to be p.ovided w ith No. 3 deformed bars for shrinkage and temperature reinforcement. Determine the spacing· required. Solution: 1. Find the cross sectional area of a {12") 30 em. strip of the slab (used in designing slab) 10 x 30 = 300 sq. em. 2. Referring to Table 9-5 using deformed bars, the value is 0.0020 x 300 = .6 sq. em. This is the required area of • steel bars per strip of slab. 3. From Table 5-:9 the area of No.3 steel bars or 10 mm diameter is .7854 sq. em. or 78.54 mm2 .7854 x 30 em. :::: 39.27 say 39 em. Therefore: No. 3 bars or 10 mm diameter will be used as temperature bars spaced at 39 em. on center. One way concrete slab is designed by making . an imaginary strip of 12 inches or 30 em. wide perpendicular with the beam that supports the floor. This imaginary strip is considered as a beam, hence, the design steps and method for rectangu lar be~m is applied where the width is equal to 30 em. and the depth is the thickness of the slab. The depth of the fl9or is purely dependent upon the span length and the magnitude of the superimposed load.
Plan (lookil!( up) Seam
Figure 9 ·- 26 182
Placement of Ban in One way Slab- The bending moment at the center of a fully cont inuous slab is equal. Therefore, there should be the same quantity of steel reinforcements at each point. In attaining the same amount of steel bars that will resist positive and negative bending of the slab, steel reinforcement are bentup alternately at the inflection point equal to ~ point of the span from the face of the beam extended over the sup.port to t distan~e of the adjacent spans. The remaining unbent bars are placed at the bottom of the slab extended at least 15 em . into the slab support or continued for several spans. For an end-span, the slab is considered as semicontinuous and that the bending moment is greater. Some designs provide an add itionaL200Jo reinforcement placed between bent bars across the supporting beam. The reinforcing bars are then hooked at the top of the termination end.
Figure 9-27 T¥fO Way Slab - Slabs which · are supported on four sides where the f loc;>r panel is nearly square is generalfy economical to employ the two directions of reinforcing bars placed at right angle with each other. This type of reinforcement will transmit the loads to the four sides supporting beams or walls. The code specifies that .thickness of the slab shall not be less than 4 inches or 10 em. nor less than the perimeter of the slab divided by 180. The spacing of the reinforcement shall not be more than 3 times the slab thickness and the ratio of reinforcement shall be at least .0025. 183
Construction Joints:
The ACI Code on construction joints
so provides: 1. Joints not indicated on the plans shall be so made and located as not to impair significantly the strength of the structure. Where a joint is to be made, the surface of the concrete shall be thoroughly cleaned and all laitance and standing water removed. Vertical joints shall also be thoroughly wetted and coated with neat cement grout immediately before placing of new concrete. 2. A delay of at least until the concrete ir columns and walls is no longer plastic must occur before casting or erecting beams, girders, or slabs supported thereon. Beams, girders, brackets. column capitals, and haunches shall be considered as part of the floor system and shall be placed monolithically therewith. 3. Construction joints in floors' shall be located near the middle of the spans of the slabs, beams, or girders, unless a beam intersects a girder at this point, in which case the joints in the girders shall be offset a distance equal to twice the width of the. beam. Provision shall be made for .transfer of shear and other forces ~hrough the construction joints.
Placement of Steel Bars - Where no ~ent bars are used in the slab reinforcements, straight bars are used for both the top and the bottom reinforcements. The bottom bars are extended at least 15 em. into the supporting beams or walls. The top bars are extended to t point of the adjacent panels. Top bars for discontinuous floor edges shall be hooked. (See Table 9 · 5).
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9 -16 RIBBED FLOOR SLAB - Ribbed floor slab is generally an economical type of floor construction but is applicable only to medium span length with light or medium load unlike the one way or two way slabs that could carry heav~ loads.
A ribbed floor slab consists of small adjacent T-Beam wherein the open spaces between the ribs are filled by clay tiles, gypsum t iles or steel forms. The t iles are generally 30 x 90 em. with depth of 10, 15, 20r 25, 30and 40 em. placed at 40 em. on center making the ribs 10 em. wide. The concrete surface layer placed on top of the tiles ranges from 5 to 6.5 em. think. The reinforcement of a ribbed floor system consist of two bars placed at the lower part of the rib where one is bent and the other rem'ained straight, or sometimes, straight hars are placed at the top and bottom of the rib, Temperature bars are either No. 2 bars or 6 mm. or wire mesh which runs at right an . gle with the ribs.
Figure 9-30
Gypsum Tile Filler - This is a lightweight material for the floor which also provides a flush ceiling finish · The common width is (9") 23 em alt hough some other sizes are available. Gypsum t iles are placed at .60 m. on center forming a ri b or web of 13 em. wide. On the r;ontrary if 30 em. blocks are used, they are also installed at 40 em. from the center same as that of clay tiles, providing 10 em. wide ribs. The Code specifies that the maximum span of ribbed floor slab should not be more than 24 times the total depth of slab and rib combined. · 186
B
Section A-A
Section B-B
Plan
Figure 9-31 Metal Tile Filler: - Are generally in the form of domes enclosed on four sides, this is sometimes called as "tin pan" construction. The metal forms are .90 Ill. long with various depth from .15, .20, .25 and .35m depth placed at the center to make a rib from 10 to 17 em. wide at the layout portion. The form widths are either .50 m or . 75 m. The .50 m forms are placed at.• 63 m. on center making a rib of 13 em. at the bottom. The metal forms maybe removed or left in place. The layer of concrete placed on top of the metal forms ranges from 5 to 7 em. thick. Steel pen form~
~··,jV'\Er·:·~·.f Section
Figure 9 • 32
Flat Slab- Flat slab floor is a rectangular slab directly supported by columns without beams or girders. The slab is either uni· for'm in thickness or provided with. square symmetrical area directly above the column reinforced with bars running in two directions. The increased area directly above the column is called drop panet or simply drop. On the other hand, a flared head is · employed in the construction of a flat-slab floor making a capital of the column . 187
When the column design is not provided with capitals, a straight flat underneath is provided in the slab throughout the system, which is called flat plata construction.
Section
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L-~===~-~-~ ~1= 1.wJ;-;=. ~;=I .W =Sectlon==;-A-A
Aan
Figure 9-33 The flat slab floor system is generally economical not only in terms of materials as well as labor and is even the most suitable type of construction for industrial buildings having a wider live load and also for building in which the use of capitals are not otr jectionable. · The advantages of the flat floor slab are: 1. 2. 3. 4. 5. 6. 7.
188
Simplified formwork Better light in the absence of beam and girder. Advantage in height for a clear story heights. Uniform surface for suspended water sprinkler system. Piping and shafting Absence of sharp cor·ners Better resistance to fire.
9-17 THE ACI ON CONCRETE JOIST FLOOR CONSTRUCTION The American Concrete Institute on concrete joist floor construction so provides: 1. The joist ribs shall be at least 4 in. or 10 em. wide, spaced not more than .75 m clear, an~ a depth not more than 3 i times their minimum width. 2. Ribbed slab construction shall conform to the limitations as provided for by the above thickness and spacing and the arrangement to span in one direction or two orthogopal directions. Otherwise, it shall be designed as slabs and beams. 3. When permanent burned clay or concrete tile fillers of material having a unit compressive strength at least equal to that specified strength of the concrete in the joists are used, the vertical shells of the fillers in contact with the joists may be included in the calculations involving shear or negative bending moment. No other portion of the fillers may be included in the design calcula· tions. 4. The thickness of the concrete slab over the permanent fillers shall not be less than 4 em .. nor Less than rl- o'f the clear distance between joists. In one-way system reinforcement shall be provided in the slab at right angles to the joists. 5. Where removable forms or fillers not complying with the provision· of No. 3 as stated above are used, the thickness of the concrete slab shall not be less than of the clear distance between joists and in no case be less than 5 centimeters. Such slab shall be reinforced at right angles to the joists with at least the amount of reinforcement required for f lexure. 6. Where the slab contains conduits or pipes, the thickness shall not be less than 2.5 em. plus the total overall depth .of such conduits or pipes at any point. Such conduits or pipes shall be so located as not to impair significantly the strength .of the construct ion.
-frz
189
CHAPTER
10
STEEL FRAMt·NG 10 -1 INTRODUCTION Prefabrication of construction parts and the methods of erecting and assembling to their designed form is not new in the field of construction. Prefabrication of parts has originated as early as the time of the Greek and Egyptian Architecture manifested in the remains of the famous Parthenon of Greece and the Pyramid of Egypt. The great Parthenon of the Greeks were built of post and lintel. type of which solid marbles were made into cylindrical form provided with enthasis and capitals plus other articulate mouldings of various forms and designs. The entablature made out from solid stone marbles enriched with carvings and decorations were done first before .they were placed on top of the post. Such fraction is similar to the modern day beam. On the otherhand the pyramid of Egypt was built out from solid blocks of stones which were fabricated off-site and assembled to its present form. Hannibal in his wars with the Romans carried along prefabricated huts across the alps. The army uses prefabricated and portable barracks and small field hospital as early as 1880 and throughout the century from World War I to World War II. Prefabricated constructions, became more popular not only for the buildings but also for bridges that could be assembled and erected in a couple ·of days. As builders became more aware .of the value of time, the use . of prefabricated building parts gained wide acceptance. Successful companies in the field of construction produced factory made homes relying on the conventional framing methods applying the technique of mass production aimed at minim izing custom job work without sacrificing the quality of thework. The recent prefabricated construction of exper imental houses sponsored by the National Association of Home Builders include:
. 1. Pre·cut steel post, beam and foundation system. 2. Combination of sheating and siding finished with polyvinyl flouride film . •3. Vinyl finished interior wallboard 190
4. Combination of sub-flooring completely finished at the factory.
5. Reinforced plastic shower stalls and roofing coated with hy.palan that are fastened to rafters by a concealed nailing strip. Fabricate - means 1o put together. The combination of pre to fabricate simply means that the parts of the structure are assembled or put together before the erection. Structural steel members in various shapes and sizes are available not only in its raw or un it fo rm but also available in prefabricated form to any sizes, shapes, or spans required by the designs.
10-2 STRUCTURAL SHAPES The most common shapes of structural steel used in building construction are the American Standard forms such as:
1. Square Bars
6. 1-Beam
2. 3. 4. 5.
7. Tee Beam 8. H-Column 9. Wide Flanges
Round Bars Plate Bars Angle Bars Channels
0 ROUND
10. Zee
n w
*' . i
SQUARE
•& &·••
Pl.ATE
L [ ANGULAR
CHANNEL
IT H I Z I-SEAM
TEE
H-COLUMN
WIDE FLANGE
ZEE
STRUCTURAL SHAPE Figure 10- 1
191
Sections or Shapes: - Is the product of rolled mill used as structural steel members represented by the shapes of their crosssections. Regular Sections: - Refers to those commonty used with higher demand. Special Sections: - Are those frequently used and rolled only upon demand or special arrangemen~.
PLATES AND BARS: The plates and bars are generally available in various sizes specified under ASTM A 7 or ASTM A36 for buildings and bridges. Flat Steel is generally for structural use classified as:
a)
Bars: 1. 15 em. (6") or less in width with 0.51 em. thickness 2. 15 em. to 20 em. width by .58 em. thick b) Plates: 1. Over 20 em. wide by .58 em. thickness 2. Over 1.20 m. wide by .46 em. thick or more
STEEL BARS: Steel bars are those specified at ( t) .64 em. wide by (1/8") .32 em. thick which are the common practice. Plates on the other hand. the preferred width and thickness are as follows: 1. Thickness: ( -f2 ) .8 up to ( t ) 12 mm. ( fe ) 1.6 mm up to over 12 mm to
(f )
5 em. 6 mm. to over 15 em.
ANGLE BARS: Angle bars are either : 1. Equal legs 2. Unequal legs The Angle bar is designated as L such as
.:
L 10 x 10 x 12mm for angles of equal legs L 15 x 10 x 12mm for angles of unequal legs 192
LL
tc} Equal leas
tb) Unequal legs
ANGLES
Figure 10 • 2
STANDARD CHANNEL The standard channel has the shape of unsymmetrical balance consisting of ·two flanges on one side. It therefore requires lateral support to prevent its tendency to b~Ackle. The standard channels are generally used as elements of built-up sections for columns and are also suitable for framing around floor openings, spandrels, and lintels attributed to the absence of flange on the other side. The channel section is identified as C 15 x 20 which means that the channel has a depth of 20 em. and weights 15 kg. per meter length.
(e)
(d)
STANDARD CHANNEL
Figure 10 • 3
WIDE FLANGE Wide flange sections are designated as W 12 x 24 which means that the flange has a depth of 24 em. and it weighs 12 kg. per meter length. All wide flange sections are generally with paraUet face flange except those with 5% slope inside face produced by Betlehem Steel Company. Comparatively. wide flange sections are more efficient than Standard I Beam with respect to bending resistance. 193
trl~-~l!i!- ~~ It!
W
WI DE-FLANGE SECTIONS
Figure 10-4
STANDARD I-BEAM The use of 1-Beam as a column is uneconomical, because the whirl or revolving action of the structure about an axis through the centroid parallel to the web of the 1-Beam is comparatively
small.
STANDARD I-BEAM
Figure 10-5
H·BEARING PILES H·Bearing piles although suitable for pile driving on deep excavations is much more suitable than the 1-Beam for columns.
(f)
H-COLUMN
Figure 10- 6 194
ZEE SECTIONS The Zee section is another structural form in a,letter Z which is not frequently used in building construction except on the fabrication of steel windows and other frames.
TTI Tee
Structural tee
Tees
Zee
lee
Figure 10- 7
10-3 STRUCTURALSTEEL The early structural steel grade was mostly focused on the ASTM A7 which concurrently is no longer considered as the basic structural steel after the introduction of new types of structural grade such as ASTM A36. However, the Code so provides that structural steel t o be used in the construction shall conform to any of the following specifications:
1. For steel bridges and buildings ASTM A7 2. Structural steel for welding ASTM A373 · 3. Structural steel ASTM A36 4. High strength structural steel ASTM A440 5. High strength low alloy structural manganese vanadium steel ASTM A441 . 6. High strengt.h low alloy structural steel ASTM A242 The ASTM A36 is stronger with higher yielding point t han the ASTM A7. The carbon content of ASTM A36 had been reduced to improve weldabiljty, al~hough it could be connected by means of bolts and rivets. 10-4 HIGH STRENGTH STEEL . The three high-strength steels are the ASTM A440, ASTM A441 and ASTM · A242 which are of greater strength and higher resistance to atmospheric corrosion. 195
The ASTM A440 is generally used in riveted and bolted cons-truction. .It is not recommended by the AISC for welding connection. The ASTM A441 is suitable for welding connection and is widely used in building constructions, because of its superiority in quality, high resistance to corrosion and higher strength but lighter in weight. 10-5 RIVETS AND BOLTS The rivets and bolts used in build ing construct ion are of three grades: 1. ASTM A141 structural rivet steel 2. ASTM Al95 high strength structural rivet steel 3. ASTM A406 high strength structural alloy rivet steel Festanen is the term used for both rivets and bolts. The three methods adopted in connecting structural steels ere rivets, bolts and welds. The choice of any of the.above mtthods depends upon the condition of fabrication and e'rtctlon, dttlll of arrange ment and condition of service 10-6
RIVETING PROCEDURES
1. The steel metal to be connected are drilled and securely held in such a manner that their holes are perfectly aligned. 2. Heated r ivets are inserted into the holes and a buckin~up tool is pressed against the rivet head. 3. The projecting shank is then covered by the power riveter which delivers rapid blows f illing the hole, deforming the shank and form ing the head. Since the rivets are heated when inserted into the hole, shrinkage will occur on cooling that the two connected plates will be drawn tightly together by the rivets. The size of the rivets depends upon the types of work, the thickness of the materials to be connected and the strength to be transmitted across the joints. The most commonly used rivets are ( ! ) 19 mm diameter and ( t ) 22 mm. However, It is suggested that only one size of rivet should be used.
196
TABLE 10-1
CONVENTIONAL SIGNS FOR RIVETS
t111o111tlveta
.....f) "'~ ~
I s: l:r· .u
CountMWunk
*""' CIIIIIIH'd
u
z ..
:ol ......
Cof.&cdlett:UM Not over t.t«b
~~
f
d
sl ~~
Floldlt""""
..
flatton.,.to~ Fl,.tt.....atof' i' &'14 f" Rlwto i! RMts 8.nd ov•r 11"
Cottn.tettunlf
!
ll•
•ll ltO>
....:.I ..
..
~: ~= ~j l;s :cf :I .. ...
...'5
l
zi! •
...:.; •• ~!
10-7 CONDITIONS FOR PUNCHING AND ORI LLING
1. tf the thickness of the plate is not bigger than the dia· meter of the rivets plus ( } ) 3 mm, the hole may be punch. 2. The hole should be ( h ) l.S mm bigger than the dia· meter of the rivets or the bolts for ease in inserting the bolts and to avoid damages of the threads. 3. The materials adjacent to the holes are usually damaged by the punching of the structural steel. Therefore, it is necessary that the hole of the punch plate should be 3 mm greater than the diamater of the rivet or bolt, thus punching 22 mm hole for. a 19 mm rivet or 25 mm for a 19 mm rivets are recommended. 4. All rivets shall be hot power driven, heated to a tempera· ture not more than 1()650C and in no case shall be driven below 5370 c.
Rivet joint may fail in any among the following conditions: 1. By shearing of the rivets 2. By crushing of the rivet or metal on which it bear. 3. By tension in the sections of the connected members 4. By tearing at the edge..
GAGE LINE: - Is the line parallel with the length of a member wherein the rivets are placed, or the· normal distance between the gage line and the edge of a member 197
b = t + 1~~" Min. = 2"
-S-1 I
Figure 10-8 TABLE 10· 2 GAGE DIMENSIONS FOR ANGLES (Centimeters) Leg
20
18
15
13
10
9
8
6
5
g gi
11.5 7.5 7.5
10 6.5 7.5
9
7.5 5 4.5
6.5
5
4.5
3.5
3
5.5 6.5
92
PITCH OF RIVETS: The Pitch of rivet is the center to center distance between adjacent rivets whether they fall on the same different I ines. The accepted minimum pitch between the center of rivet holes shall not be less than 9 em. for ( 1") 25 mm rivets; 7 em. for 22 mm; 6 em for 19 mm rivets; and 5 em. for 16 rivets. Pitch should not be less than 3 times the diameter of the rivets.
Figure 10 - 8a
198.
TABLE 10 • 3 MINIMUM PITCH TO MAINTAIN 3 DfAMETE RS CENTER TO CENTER OF RIVETS Diameter DISTANCE, g, centimeters em 2.5 - 3 of Rivet M 4 4.5 5 5.5 6 7 7.5 mm. 16mm 22mm 22mm 25mm
4
5 6 6.5 7.5
5 6.5 7.5
3.5 5
4
3
6
5.5
7
6.5
1.5 3.5 5 6.5
0 2.5 4.5
6
0 3.5 5
2 4
3
0
EDGE DISTANCE OF RIVETS: Rivets or bolts placed so close to the edge of the pJate have the tendency to tear the adjacent thin metal. A standard' specification requires a minimum edge distance of holes as shown on the following Table 10-4. The maximum distance from the center of any rivet or bolt to the nearest edge shall be 12 times the thickness of the plate but shall not exceed 15 em.
STITCH RIVETS. Truss members are usually built up of two angles provided with gusset plate that separate the two angles. These angles act as ·one unit by the use of rivets connecting the members placed at intervals between the ends of the members. This is called sti1Ch ·
rivets. TABLE 10 • 4 Rivet or Bolt Diameter (m.m.)
MINIMUM E[)GE DISTANCE FOR HOLES Minimum Edge Dist,ance for Punched, Reamed or Drilled Holes (Centimeters}
At rolled Edges of At Sheared Edges
16mm 19mm 22mm 25mm
Plates, Shapes or Bars or Gas Cut Edges
3
2.5
3.5 4 4.5
3
2.5 3.5
199
10-8 BOLTS Bolts used t o con nect structur.al steel are either common bolts or high strength bolts. ' Common bolts are not permitted in some Codes for building construction for more than a prescribed height but rather limited to field connections or to work of less importance not subject to shock or vibration and those buildings containing machineries or rolling loads that will cause loosening of the nuts which will substantially reduce the strength of the connections.
High Strength Bolts: - Are usually made of ASTM A325 steel which have been used for years in bu ild ing construction . High strength bolts prov ide a resisting force. by friction between the contacting surfaces of the plates, eliminating bend ing, shearing or bearing stresses on the bolts. Bolts and rivets are called "fasteners:· : Bolts are called "threaded fatteners". Bearing Type Connection: - Where the end of the plates are • in bearing against rivets and the shank of the rivets that resist shear. Friction Type Connection: When high strength bolts are used. tensile stresses are set up in the shank of the bolts and the frict ion between the plates which resist the tension and compression load . TABL E 10-5 HIGH-STRENGTH BOLT TENSION Nominal Bolt Diameter in mm.
16 mm 19mm 22mm 25 mm
Klg.
Minimum Bolt Tension Newton
8,727 12,900 16,380 21.470
85,400 126,3 20 160,350 210,160
10-9 CONNECTIONS OF STRUCTURAL MEMBERS
1. The Column Base Plate:- Spreads the column load over the foundation in various sizes where the length in meter and thickness of 2 mm increments. Rolled steel gearing plates should
200
be in absolute contact for proper ' distribution of load. Plates ot more than 5 mm to 10 mm thick maybe straightened by pressing or planning. · Steel column should be properly anchored to the foundation by steel bolts which passes through the plates and angles riveted or welded to the flange of the column. Angles are sometimes omitted for light columns, instead, the base plate is secured to the column by means of fillet wel<1,. . ·
~
I I. I
,,
b.
,·1.
Welded connection for columns and base plates, the a(lgles are shopwelded to the column and field welded to the base plate. '
Figure 10- 9 · 2. Column Splices: - Are usually made at 60 em. or more above the floor levels. Splices are generally made by riveting or welding splice plates of 10 to 12 mm thickness to the flanges of the columns. The splice plates does not resist compression load but only serves to hold the column sections in the right position. Where the upper column is smaller in width than the supporting . column, filler plates are used. If the difference in width is so great, a horizontal plate is used instead. ·
201
.
;:
_ii_
:1
+il: ... ...+It+ +U+ -- ... ... +:: ... ...+!! . :; +::+
....
....: ... tl
+ll+ ±-~L-! +!!+ ...... :::: ......
II
... ~--
II II II
.. (aJ
..•
~
'
I""""" ~
-.. .
..
~
(b)
.
.
II
(c)
I
I
J..4.
-
Ii
(d)
(e)
I
II
! ·~
T! T
_.
II
ii
I
I
i_ !
!
•
.I
_._I !
iI -•
I
(f)
(a) The splice plates are not design to resist compressive stresses but only to hold the column sections in position. (b} and (c} A horizontal plate is used to attain a full bearing area between the column. (d) to (g) Auxilliary plates and angles are shop welded to the column then bolted in the field before making the permanent welds.
Figure 10-10 3. Beam Bearing Plate: - Beams to rest on masonry watls or pier usually are provided with bearing plates to provide an angle bearing area and to attain a uniform distribution of the beam load. The bearing pcates are usually not riveted nor welded to the beam flange.
202
I .
Figure 10-11 4. Beam Connections to Columns: - Beams connected to columns has a great variety of condittons using rivets or weld anchorage. For large beams, seat connections with stiffeners are commonly employer! which usually consists of shelf angle and single or double angles. The filler should be the same in thickness as the shelf angle. The top angle, or clip angle is used only to hold the beam in its right position but not to assist in transferring the beam load to the column.
..
.!
I I
i
M
t~ oo
v
I. E~tH-B rr1r r~ I C&J
I (c)
w
m
Figure 10-12 5. Seat Connection without stiffeners maybe used for beam with smaller reactions.
203 .
t:;..
:r t:... lol
lbl
(<}
(d)
(•)
lfl
~
(a), (b), .and (<:) Seated connections consist of a shelf angle filler and single or double stiffener angles. The top angle or clip angle only serve to hold the beam In position and does not help in tran,. fering the load to the column. (d), (e) and (f) Beams for smaller reactions. (g) A welded stiffened seate~ beam connection to column.
Figure 10 • 13
a.m
6. to Girder Connections: -The methods commonly adopted in connecting beams to girders is by attaching two angles to the web of the beam connected either by rivets, bolts or weld.
GJ rn urn aJ
~
~
w
(a} Framing beam to a girder (b) Weld replace rivets or bolts in securing the connection angles to the web of girder (c) Connection angles welded to both beam and girder. '
Figure 10- 14 7. Rivetlld Framing: -The different types of riveted framing
are: ·a) When a beam is supported by another by placing on top of it, rivets or bolts are used just to hold the beam.
T
;
-
.
Figure 10- 15 b) Frame connections using connecting angles commonly used for beams and girders.
Figure 10 • 16 c) A seated connection without stiffener or side angles are used.
angle~
but only top
d) Flush top refers to the connections of two beams where the upper surface. of the top are of the same level. This could be done by cuttfng away a portion of the upper flange known as coping or blocking.
'
I I I
I I I
~j k--;-------~ ------~
. I 1 lo I ~
205
fill er Bea"' Or a llped to Avoid Cop ln q
Figure 10- 1/
COMMENT: Coping or blocking method. is not a good practice, since it involves additional expenses besides the reduction of the material which may affect the strength of the beam.
10 • 10 PLATE GIRDERS When a rolled steel sections are inadequate to meet the span requirements built-up section plate or box girder is the solution . A plate girder is a beam made up of steel plates and angles either riveted or welded together forming an 1-section. When the web of I section consists of two separated steel plates, the structure is called box girder.
BOX GIRDER
BUILT UP PLATE GIRDER
Figure 10- 18
The axial vertical plate is called the "web plaW". Flange angles are placed at the top and at t~e bottom of the web plate secured by rivets. One or more plates are riveted to the outstanding legs of the flange angle called mvar pletes and a stiffener m~de of angle section riveted to its side to prevent buck ling of the web plates. In welded plate girders, the flange angles are omitted since the cover plate could be connected directly to the vertical plate. The three principles involved In making built-up plates are: 1. Web plate is to resist shearing stresses 2. The fla nge made-up angles cover plates and t of the web area, wil l resist tension and compre$sion stresses due to bending. 3. The stiffeners serves to prevent buck ling of the web plates.
BUILT u ·p SECTIONS
Figure 10 · 19
10-11 WEB PLATES AND INTERMEDIATE STIFFENERS The Code specifies a minimum thickness of web plate to be
10 mm for interior and 6 mm for exterior locations. In addition, plate dirder web's thickness should not be less than 3~ of the
unsupported distance between the f lange angles. If full allowance bending stress in the flange is used, the web plate thickness should not be less than 1l~ of the unsupported distance: This requirement apply to ASTM A36 steel. The intermediate stiffness that prevent buckling is usually 6 x 6 em. x 6 mm angles placed in pair at each end of the girder then at a distance not to exceed. 85 em as f irst pair of intermediate stiffness then at 2.25 m. thereafter.
207
... m =.
·ec- plate$
~ --+--1
.. 1
c.. piMn STIFFENE RS BEARING PLATE
·-·
Figure 10- 20 An Open web Steel Joist is considered lightweight structure to support floor and panels between main supports. '""'i I
I - --
l;i.
I!i. j::.,
.. PLAN
S TEEL BEAM SUPPORTING STEEL JOIST
Figure lO- 21 208
TfL
Y. • rivets 1 ~· holes
~~
auuet plates
All lln&les ion& less back to beck W.b memben 2 L 2 ~ x 2 x Y.. Pur1ins 9 [ 13.4
209
WE \..t>€0 CONIU C T ION S 'o\IE.l.l>EO EN1> JOINTS
EN O JOINT WITHOU T SHOE .ANGLIES
OI!SIGN OF £NO J "OINT WITH SHOE ANGLE·
210
10- 21 ROOF TRUSSES Roof trusses is the most economical structure to cover a building having a wide span of supporting columns or walls. A truss is a structural frame generally supported only at both ends by columns, beams, or walls.
The different types of trusses are:
1. King post truss 2. Simple fh1k truss 3. 'Fink truss
7. Single span fink truss 8. Clipped truss 9. Rigid frame open-web clear span truss 10. Rigid frame clear span 11. Single span slope beam
4. Howe truss 5. Pratt truss 6. Fan Truss ·
12. Continuous Seam
~~ SIMPLE FllfK TIIUSS
"OWE
KIKG POS T TIIUSII
PRATT
TRUSS
FAll TRUSS
fiKK
TRUSS
TRUSS
THR£E·IUN6£ ~!lAME
Figure 10- 22
21l
PURLINS: Purlins is a beam placed on top of the rafters or top chord that extends from truss to truss which carry and transfer the roof load to the truss at the panel points.
Roof Panel: - Refers to the roof portion that Hes between two adjacent joints of the upper chord, in short, roof panel is that portion of the roof supported by each purl ins.
Sag rods: - Refers to a steel bar usually of 16 mm or 19 mm diameter rod attached at the center or endpoints of the span of the purlins. Sag rod is secured to the purl ins over the line of the ridge truss usually placed at 7 em. below the top flange of the purl ins. Root ?a"nal
~-
Figure 10 - 23
10-13 WELDED CONNECTIONS The advantages of using welded connections are: 1. Minimal noise in the erection of structure 2. Savings on labor and materials 3: Rigidity of frame 4. Easy to correct new work to existing structure and also its repair. 5. Simplicity of design
212
Arc Welding:- Although arc and gas welding are permitted in the connection of structural steel members, arc welding is the one most preferred. Penebatlon: - Is the term used to indicate the depth from the original surface of the base metal to the point ·at which fusion ceases. Partial penetration: - is the failure of the weld metal and base metal to fuse at the root of the weld.
Welded Joints:- Are classified into three: 1. Butt joint 2. Tee Joint 3. Lap Joint The selection of the type of weld to be employed depends upon the magnitude of the load requirements, the manner in which it is applied, and the cost of the preparation and welding operation. The weld that is commonly used in building construction is the fillet weld which is somewhat triangular in cross section form· ed between the intersecting surfaces of the joined members. The minimum effective length of a fillet weld shall not be less than 4 times the weld size. The 5 mm fillet weld is considered the minimum size and an 8 mm weld is the most economical size that · could be made by one pass of the electrode. A small size conti· nuous weld is more economical than a bigger discontinuous weld. Large size fillet w~ld requires two or more passes of the electrode.
f
I
(o) Squar• JI'OOVO joitlt
(b) Sifl&le·vetlf'OC)Vtl
tf
joint
I
t
(el Double-vee POCM joint
~+~~
f
(dl Sinlle bevel·- jllint
f
I
+f
I
ld Square 1M joint
~~ f .
(81 Sinale fillet lap joint
WELC
• f
mDouble beveiltOO\Ie joint
f
9
f
fill Doubtt fitfet ''"joint til Sin.lt-U groove joint SYMBOLS 8 C:ONNECT10NS
Figure 10 • 24
213
Shop Weld: - Where the structural members are welded in the shop before delivering at the site.
Field Welding: structural members.
Welding done during t he erection of the
Plug and Slot Welds: - In connecting two overlapping plates by means of welding, holes are made in one of the two plates then plug and slot welds are made at the entire area of the hole or slot. The maximum and minimum diameters of the plug and slots including its length are shown on the following illustration: .a. ........ . .. . ,.,., .... D. ~ ... ~'" """ '•
lle- L · !O • ~
L·thl ~
ED 'I
D- ljMtotl llltt-
' t tl'tl:/'.i tl t I,
!. [gar
I I
I
I t
. t I
t•J
D
l_l
{<)
PLUG AI'I O SLOT WELOS
Figure 10- 25 Note: Since there is no st andard welding connections formu lated for beams, the designer has to make the selection of the type of weld which accord ing to his judgement will be most practical and economical. Welding may be done either by shop weld, field welding or both upon the discretion of the designer.
TABLE 10-6 BASIC WELD SYMBOLS Plug Back
Fillet
~
~
or
Slot
Groove or 8 utt SqiJare
CJ II
v
Bevel
v v
u
v
y
SUPPLEMENTARY WELD SYMBOLS Weld aU Around Field Weld
0 2U
•
J
Contour Flush
Convex
-
,.............,
f1lre AireY 8e¥el
''
lr
CHAPTER
11
TIMBER ROOF FRAMING 11- L INTRODUCTION The earl~ age constructions of house framing were built substantially strong and durable. Construction of houses by our. fore· fathers have strictly observed the principle of durability and lasting quality of the materials. Only selected wood were used in the construction. Lately, the introduction of power tools, machines and saw· mil-ls plus human greed has ruthlessly abused and destructed our forests that the present construction has already precluded such way of construction. Houses were built totally disregarding its lasting quality, classification of lumber and its particular use in the construction are no longer observed, the age of the tree. its falling season including the proper drying and seasoning are totally disregarded. If builders are to be blamed, more so with the homeowners who could not meet the expenses of a first class construction. Nobody would like to own a house ·built from materials of poor quality, but quality demands substantial appropriation that only few could afford.
Under the present trend where house rental increases at an average of 10 percent every year,prospective homeowners are being forced to embrace the neck-deep agony and burden of long term installments. To a family of average or below average income, a house and lot is considered as a fulfillment of their aspiration regardless of its quality and cost. Unfortunately, that fancy house beautifully painted, deteriorate faster than the 20 to 25 year term to pay the monthly amortization of the loan. Numerous homeowners were disappointed when their dream house were blown up by typhoon because of poor quality and under sized lumber used in the construction of the roof framing. To · those who are planning to construct or own a house, it would be better to reduce the floor area of the house rather than .sacrifice the quality through the substitution of cheaper and poor quality materials. It is therefore important to select good quality of lumber for your house framework. 215
11 - 2 TYPES OF ROOF There are several forms of roof and numerous variety of shapes that one has to be familiar with: 1. Shed or Lean-to Roof 8. Gambrel Roof 2. Gable or Pitch Roof 9. Ogee Roof 3. Saw Tooth Roof 10. Mansard Roof 4. Double Gable Roof 11. French or Concave Mansard Roof 5. Hip Roof 12. Conical Roof or Sphire 6. Hip and Valley Roof 13. Dome 7. Pyramid Roof 14. Butterfly Roof
Shed or Lean-to Roof- Is considered as the simplest form of roof consisting of one single slope.
SH£1> OR LEA II - TO
Figure 11 - 1 Gable or Pitch Roof- The most common type and economical form of roof made of triangular sections consisting of two stapes meeting at the center of the ridge forming a gable.
GAll£
Figure 11 • 2
Saw Tooth Roof- Is the development of the shed made into a series of lean-to roof covering one building. This is commonly . used on factories where extra light is required through the window on the vertical side. 216
$Alii l'OOTH
Figurell-3
Double Gable Roof: -Is a modification of a gabfe or a hip and valley roof.
Figure 11· 4
Hip Roof: - Is also a common form used in modern houses having straight sides all sloping toward the center of the building terminating at the ridge.
HIP 11001'
Figure 11 • 5
Hip and Valley Roof:- ls a combination of a hip roof and an intersecting gable roof forming aT or L shape.d building. This type . of roof form however, has a variety of modification which are not illustrated. 217
1+1" 4110 VAI.I.I't
Figure 11-6
Pyramid Roof: ts a modification of the hlp roof wherein the four straight sides are sloping towards the center terminating at a point.
P'tltAMtO
Figure 11 · 7 Gambrel Roof:- Is a modification of the gable roof with each side having two slopes.
Figure 11-8 OGEE Roof: -
Is a Pyramid form having steep sides sloping
to the center.
Figure 11 • 9 218
.
Mansard Roof: - Where the sides of the roof slope steeply from each side of the building towards the center forming a flat deck on top.
MAII$AIIO
Figure 11 • 10 French or Concave Mansard Roof: - Is a modification of the Manzard Roof where the sides are concave. Dome: -is a hemispherical form of roof usually used on observatories. Conical Roof or Sphire: - Is a steep roof of circular section that tapers uniformly from the circular base to a central point.
FR£NCH OR COMCAVE MAMSARD ROOF
DOME
Figure 11 • 12 .
Figure 11 • 11
Figure 11 · 13 219
Butterfly Roof: - Is 1 two shed roof where the slope meet at the center of the building.
IUTTEit,LY
Figure 11 • 14 11 • 3 TYPES OF ROOF FRAME The three types of roof frame commonly used are: 1. Rafters Type
2. Truss Type 3. Laminated Type
The various kinds of rafters for roof construction are: 1. Common Rafters 2. Hip Rafters
3. Valley Rafters 4. Octagon Rafters 5. Jack Rafters Common. Rafters: - Are rafters extended at right angles from the plate or girts to the ri~ge. ·
-Uf'IOI
Figure 11 • 15 220
Hip Raften: -Are rafters laid diagonally from the corner of a plate or girts to the ridge.
Valley Raftan:- Rafters placed diagonally from the plate or girts at the intersection of gable extension with the main roo"f. Jack Rafters: -Any rafter which does not extend from the plate or girts to the ridge. Jack rafters are classified Into: 1. Hip Jacks
2. Valley Jacks 3. Cripple Jacks Jack rafters framed between hip rafters and girts are called Hip Jacks. The frame betwMn the ridge and valley rafters are called Valley Jacka, while those frames between the hip and the valtey rafters are called Cripple Jacka.
Figure 11 • 16
Octagonal Raflars: -
Are rafters placed on an octagonal
shaped plate at the central apex or ridge pole. 221
OCTAGOHA~
RAFTERS
Figure 11 - 17
Trust: -Truss is a built-up frame commonly employed on a long span roof unsupported by intermediate columns or partitions. Truss is a design of a series of triangles used to distribute load, stiffen the structure and flexibility for the interior spacing as welt as strength and rigidity. The different types of trusses are: Light trusses {trussed rafters) 1. Pitched Truss 6. l! story frame 2. Howe Truss 7. Utility 3. Scissors Truss 8. Flat 4. Raised Chord Truss 9. Bowstring 5. Sawtooth Truss a)
b) Heavy Trusses 1. Howe Trusses 2. Belgian Truss 3. Fink Truss 4. Pratt Truss 5. Scissors Truss
6. Cambered Fink 7. Saw Tooth 8. Flat Pratt
9. Flat Howe 10. Warren
Gir1J- Is that structural member that supports the rafters or trusses of the building. Collar the roof.
a..n -
The ties between rafters on opposite sides of
.
~
LIGHT TRUSSES
~
I'IT~M!D
HOWE
S CISSORS
IIA IS£0 CKOIIO
IJliLl TY
80WSTR IIIQ
HEAVY TRUSSES
~'·" · '-·~m. ~
~
9.00-2..,.0Qm .•
~
MOW£ TIIIISS
at:LGIAM
~-mom
~
9 .00- 11·0011\ . ...
PRATT
I' I IIX
~-"l.so-ao.oom. ~
7.so-2.o.oom. CAMBER£0 FIMK
S~ISSORS
WAitllt:M
FLAT HOWE
-s.oo-ta .oom. 9 .00
~
-·2~.00 -l-~-~-....;ll.-.....li<......---"~C;--.¥..--' FLAT I'll AT T
SAWTOOTH
Figure 11 18
223
Purlins - The structural member placed on top of a rafter or top chord of a truss that supports the roof sheating. TABLE 11·1 PURLINS SIZE AND SPACING
Span
Size
2.00 3.00 3.50 4.50 . 5.00
2X3 2X4 2X6 2X6 2X8
Length
Spacing
of Roofing
of Purlinslm}
6'
.75 .60 .70 .60 .67 .67
7' 8' 9' 10• 12'
TABLE 11-2 PURUNS SPACING IN METER Length of Roofing · sheet
1.50 2.00 2.50 3.00
Distance of Purlins
.60 .57 .55
1~
.68 M
4.00 4.50 5.00 5.50 6.00
.62 .60 .67 .65 .63
End Lap
.30 .30 .30 .30 ~
.30 .30 .30 .30 .30
Note: The phasing- out of the English measure might affect the present commercial width and length of the roofing materials particularly the G.l. Sheets which are common and popularly used in most construction work.
224
It is most likely that the length will be made to an increment of .50m of which corrugated G.l. sheet will start from 1.50m to 6.00m long or more. Consequently, this new length will govern the spacing of the · purlins. Table 11-2 is presented in anticipation of the new spacing of the purlins if roofing sheets are manufactured in accordance with the new Sl measure. 11 - 4 TIMBER FRAMING FASTENERS:
Nails -There are numerous variety of nails to meet the needs of all kinds of constructin. They maybe clamped wit. : respect to shape. Nails are either cut or wire. Cut nails are rectangular in shape directly cut from a metal strip, likewise, w ire nails ~re common nails with circular cross sect ion which are cut directly from wire. With respect to service, nails are classified as common, flooring, finishing, roofing, boat etc. Fasteners for timber framing usually specify the use of common nails.
TABLE 11-3 COMMON .Desig"lat ion
6 d 10 d 20 d
30 d 40 d 50 d 60 d
NAILS FOR TIMBER FRAMING
Length (em.) 5.0
7.5 10.0 11.5
12.5 14.0 15.0
Lateral Diameter (mm) , Resistance per nail (kg.)
.29 .37 .52 .56 .65 .66 .72
24 40 ' 45 - 75 68 - 88 80 - 102 113 - 121 100 - 146
If nails are driven parallel with the grain, the lateral resistance should be decreased by 25 to 33o/o.
Wood Screw - Are used to avoid splitting and injury to the wood and to obtain better fitting and ease of disassembling when necessary. 225
Screw should not be spaced less than 3 em. across the grain and not less t han 5 em. parallel with the grain. For hard wood, spacing should not be less than 4 em and 6 em respectively. TABLE 11-4 SAFE LATERAL RESISTANCE·OF SCREW
Gage of Screw
Safe Lateral Diameter (mm) Resistance per screw (kg.)
•6 8 10
3.5 4.1 4.8 5.5 6.1 6.8 7.5 8.1 8.8 . 9.5 10.0
12 14 16 18 20 22 24
26
37 50 71 93 116 143 173 205 239 278 318
Lag Screw - Is used in fastening large pieces of t imber under heavy stresses. The diameter of the lag screw vary from 6 mm to 25 mm and the length from 4 em. to 30 em. Lag screw is preferred where bolts are difficult to install.
drift bolts
CJ=;=Ot . bolts
Figure 11- 19
Bolts -Are the rnost popu lar for fastening timber joints with small or big stresses. Bolts in roof framing are classified as: 1. Common, Ordinary or Machine Bolts 2. Drift Bolts 3. Strap Bolts .4. U-Bolts 5. Eye Bolts 226.
Drift Bolts and Dowels - Is a round or square iron or steel with or without lead or point of specified length. Drift bolt is driven into the hole of the timber with a diameter 80% smaller than the bolts and the minimum diameter is 20 mm. This will prevent the lateral .movement and separation parallel with the axis. On the other hand. a dowel, which is thicker and shorter than the drift bolt only prevents lateral displacement of the con nected parts. Dowel is either iron or wood pin extended but not through the members of the structure to be connected.
The disadvantages of dowels ara: 1. It does not provide a rigid joint 2. It is totally damaged if repair calls for defective lumber.
3. It is hard to replace. Wooden Key - Is made of a piece of hard wood, rectangular in cross section inserted between two lapping pieces of lumber intended to prevent sliding of the adjacent members. The keys are parallel or inclined as shown In the following figures.
Split Ring
Inclined Key
m
LIJ
Shear Pins
Pins Figure.ll-20
Shear Pins may be of hard wood, steel bars or G.J. Pipes.
227
..
1. 2. 3.
(O$t 1ron robbed wo~hers Ma lleable i ron washers Square steel plate washers
4.
5. 6.
Cost iron O.G. woshtr5 Bevelled cost iron washers C irculor pressed steel wo~ers
Figure 11-21 Plate washers are used under the head and nuts of the bolts to prevent the heads and nuts from damaging the timber when tightening the bolts. The washer also provide sufficient bearing area. The thickness of the washer should not be less than 1Jz of the bolts's diameter plus 1.5 mm. TABLE 11-S* BOLTS AND WASHERS THICKNESS AND NlT lURING AREA NET BEARING SIZEOF BOLTS
mm 15.0 2 ~ ! 3 /.5 3 ! 8.0 i 4 25 10.0 28 4~ .11.5 5 ~2 1~.0 6 38 ]5.0 1~ * Materials ore wrought iron (W.I.l Inches
a
mm 12 16 19
DIA OF WASHERS THICKNESS Inches
1,IA
Inches
mm
A
12
~
16 19
e
A 1A 1l
AREA
22 28 32
in'
3.78 6.76
7.86 11.79 ]4.91 18.41 26.50
38 1i and Steel Rod
cm2 24.3 :34.6 50.6 76.0 96.0 118.5 171.0
11- 5 INTERMEDIATE JOINTS Joints must be within the center lines of the member meeting on a common point so as to prevent rotation at the joints. As much as possible, wood joint should not be used to coun· ter act tension forces, unless, steel strap, g..~sset plates with bolts are employed. For structure with smaller stresses, wood connections shall be provided with dapplng or notching the strut to the adjoining member using dowels, lag screw or nails to keep the member in the design position. On the otherhand, for structure with large stresses, metal bear ing plate, or casting side plates, bolted con· nect ions or bearing blo~ks shall be-specified. 228
Pocket jolntt that collect moisture should be avoided, all
joints 1h1ll be kept aligned as simple as possi ble for ease in the carJ)4tntry work.
IIOTCHINO or 0APPING
8\JTT
B\.OCIC
Figure 11-22 When. a strut is at right angle with the top chord, 1·19 mm. dowel or 16 mm. lag screw is employed to hold the strut in place. When the strut carries large stresses, the follow ing joints can be used.
L 2. 3. 4.
Butt Block or A ngle Block. Steel S-shaped Bearing Plate Cast Iron angle solid bearing block Cast Iron angle bearing block with a web
Butt Block - Is made of hard wood wit.h the same th ickness as the top chord. The length of the block should be adjusted to fit all possible conditions and interference with other connect ions.
Steel S-sheped Bearing Plate - The bearing plate should be the same width as the top chord.
ST[EL S · Bf~AR IN G
PLAf£
\•. •
,.
Figure ll-23 229
C•t Iron Solid Bearing Block - The bearing -block is solid and covers the whole width of the top chord casted at holes not less than 16 mm thick provided with a lug into the top chord.
C. I . SOl.lO 8EARII'IG BLOCK
Figure 1 1 -25
Cast Iron Angle Bearing Block with a Web - Should have a minimum thickness of 25 mm.
C.l . AMGLE 8EARII'IG &LOCK WITH A WEI
Figt,Jre 11-26
Center Joint of Howe Truss- This type of joint is provided with a butt or angle block at the center intermediate joint.
• Bull or An gle 8 \ocll .
Figure 11- 27 Peak Joint- Has various types depending upon the design as shown under tf1e following illustrations: ·
230
with collar plate
solid cast Iron block
hollow cast I ron block is used
Figure 11-28
11 - 6 END JOINTS
There are five typas of end joints 1. 2. 3. 4. 5.
Pinning the top chord into the bottom chord. Notching the top chord into the lower chord w ith bolts. Using bent strap or shoe plate with lugs or flats. Using the side plat es with flats or tables. Using malleable cast iron shoe.
1. Pinning the top chord into ·the bottom chord is the simplest form of end joints employed on small structure.
.
Machine. 'aoH"-
Bottom Chord
flg.fl-27 2. Notching the top chord into the lower dtord with bolts are of the following types: {1) Notching with bolts. 231
8 OIIOift Chord
2, Notching with bolts with wood key
3.
By the use of bent strap with lugs or flats.
4. By the use of steeel side plate with flats or tables riveted to the plates.
Figure 11-SO 232
5. By using Malleable cast iron shoe
Figure 11-31
11 - 7. SPLICING: Splicing is the process of joining two pieces of timber in their longitudinal direction in order to transmit stresses from one membef to another. Splicing are of three different ways:
1. By Lapping 2. Fishing 3. Scarfing Lapping- Is simply by joining one. member on the other. Fishing - Is by joining two ends with the use of two side blocks sometimes called splice pads.
Scarfing- Is by cutting away the opposite sides of two mem· bers then lapped to obtain a continuous piece of uniform thickness. The common types of splicing tension memben are: 1. 2. 3. 4. 5. 6. 7.
Bolted wooden fish plate splice Bolted steel fish plate Wooden tabled fish plate splice Shear pin splice Steel tabled fish plate Tension bar splice Timber connector splice
233
BOLTED WOODEN FISH PLATE
SHEAR PIN SPLICE
BOLTED STEEL FISH PLATE
STEEL TAB.LEO FISH PLATE
1:: ~~~ ~:1~ llt...:tJ =+ ll
WOODEN TABLED FISl11'LATE
TIMBER CONNECTOR SPL\CE
A
<
....._. g. ~
~
4 ~
....!L:
-.....
2
d
II ~
....~-....._.d.__.....,, BUTT JOINT
..d... 2.
I -~ HALF LAP
.I
1
08Lf0UE ICARF.
SPLICING COMPRESSION MEMBER
Figaue 11-32
234
11-8 OLUED LAMINATED LUMBER Structurally glued laminated wood is a stress rated product of timber produced in laminating plant from selected wood securely laminated and bonded together with adhesive. The grain of the wood are mostly longitudinally parallel with each other forming any length and bent to curved shapes during the process of gluing the lamination. Thickness should not exceed 5 tm. net. When bending radius that is too sharp to permit the use of 5 em. thick lamination, a nominal thickness of 2.5 em. lumber is usually used. the various forms of laminated structures are:
1. 2. 3. 4.
A-Frame Gothic Parabolic Radial 5. Three Centered 6. Straight
7. Tudor Three Hinged Arc
8. Single Tapered Straight 9. Double Tapered Straight 10. Double Tapered Curve
11. Pitched 12. Double Tapered Pitched 13. Curved
GOT HIC
TUOO ~
s-Mo K~ O
r:
n
ST U I GHT
UCII.
1
OOUet.£ TA'EUO • $TAAIOT
tltACtA L.
Figure .11-36
23.5
WOODEN HOWE ROOF TRUSSES (sizes of members)
TABLE 11-6 4 PANELS TRUSS TOP CHORD SPACING T.C. in meters
BOTTOM CHORD B.C.
5M
1.50 2.00 2.50 3.00
3x4 3x5 3x5 3x6
Jx4 3x4 3x5 3x5
3x6 3x6 3 x6 3x8
3x5 3x5 3x6 3x6
2.50 3.00 3.50 4.00 .
236
3x8 3x8 3x8 3x8
3x6 3x6 3x6 3x6
c
12 mm 12mm 12mm 12 mm
12 mm 12 mm 16 mm 16mm
12 rnm 12 mrn 12mm 12mm
12mm 16 mm 16mm 16mm
12mm 12mm 12mm 12mm
16mm l.6mm 19mm 19mm
SPAN 2x3 2x3 2x3 3x3
7M
VERTICAL
8
SPAN 2x2 2x2 2x3 2x3
6M 2.00 2.50 3.00 3.50
DIAG. A
SPAN 2x3 3x3 3x3 3x3
TABLE 11·7 6 PANELS TRUSS TOP BOTTOM SPACING CHORD
DIAGONAL B A
in meters
2.50 3.00 3.50 4.00
3x8 3x8 3x8 3x8
3x6 3x6 3x8 3x8
2x3 2x 3 2x3 2x3
3x3 3x3 3x3 .3x 3
c
VERTICAL D E
mm
mm mm
12 12 12 12
12 12 12 12
12 12 12 12
12 19 12 . 22 12 25 12 25
12 12 12
12 12 16
19 19 22 22
9M SPAN . 3.00 3.50 4.00 4.50
3x8 3x8 3x8 3x8
3x6 3x8 3x8 3x8
2x3 3x3 3x3 3x3
3x3 12 mm 3x3 3x3
10M SPAN 3.00 3.50 4.50
3x8 3x8 4x8
3x8 3x8 4x8
3x3 3x3 3 X 3. 3x3 3x3 3x3
19 22 22.
237
TABLE 11-8 B PANELS TRUSS SPACING
TOP CHORD
BOTTOM CHORD
DIAGONAL A
in meters
12M
4.00 4.50 5.00 5.50
4x8 6x6 6x8 6x8
4x8 6x6 6x6 6x6
3x3 3x4 3'x4 3x4 13M
4.00 4.50 5.00 5.50
4x8 6x8 6x8 6x8
4x8 6x6 6x8 6x8
3x3 3x4 3x4 3x4 14M
4.00 4.50 5.00 5.50
238
6x8 6x8 6x8. 6x8
6x6 6x8 6x8 6x8
.3 X 3 3x4 3x4 3x4
B
c
VERTICAL DIAMETER mm X y 0
z
SPAN
3x3 3x4 3x4 3x4
16 16 16 16
19 19 19 22
28 28 31 31
3x4 4x4 4x4 4x4
12 12 12 12
3x4 4x4 4x4 4x4
12 Hi 19 28
3x4 4x4 4x4 4x4
12 12 12 16
SPAN
3x3 3x4 3x4 3x4
12 16 19 28 12 16 22 31 12 16 22 31
SPAN
3X3 3x4 3x4 3x4
16 16 16 19
19 19 22 22
28 31 31 41
2 PANELS
TABLE 11· 9 TOP TRUSS SPACING CHORD in meters
1..50
2.00 2.50
BOTTOM CHORD
DIAGONAL A
VERTICAL
y
X Diameter
3x5 3x6
3x5
3x6
3x5
2x3
2X 3 2x3 3X'3
3x5
2x3 3x3
12mm 12mm 12mm
TABLE 11-10 3 PANELS TRUSS TOP BOT:T'OM DIAGONAL SPACING CHORD CHORD A B (in meters) 4M 1.50
2.00 2.50
3..x4 3x5 3x5
3x4 3x4 3x4
2x3 2x3 2x3 5M
2.00 2.50
3x6 3x6
3.00
3x6
3x5 3x5 3x5
2x3
VERTICAL
y
X
z
Diameter
SPAN 2x 3 2x3 2x3
2x3 2x3 2x3
12mm 12mm 12 12 12 12
12mm 12 m!_n 12 12 12 12
SPAN
2x3
2x3 2x3
2x3 2x3
2x3
2x3
2x3
239
TABLE 11 • 11 Truss Top Spaci ng Chord in meters
4PANELS Bottom Chord
DIAGONAL
A
B
c
VERTICAL
0
X
y
z
Diam eter
mm
. 6M SP AN
2.00 2.50 3.00
3x6 3x6 3x6
3x5 3x5 3x6
2x3 2x3 2x3
2x3 2x3 3x3
3x3 3x3
3x3 12 12 12 3x3 12 12 16 3x3 12 12 16
3x4 3x4 3x4
3x3 12 12 16 3x3 12 12 16 3x4 12 16 19
3x~
7 M SP AN 2.50 3.00 3.50
2.4 0
3x6 3x8 3x8
3x6 3x8 3x8
~·
3x3 3x3 3x3
3x3 3x3 3x4
~
...,
3x8 3x8 3x8
3x8 3x8 4x8
3x8 4x8 4x8
3.00 3.50 4.00
3.00 3.50 4.00
3.00 3.50 4.00
3x8 4x8 4x8
3x8 3x8 4x8
3x8 3x8 3x8
3x3 3x3 3x3
3x3 3x3 3x3
2x3 3x3 3x3
TABLE 11· 12 5 PANELS Truss Top Bottom Spacing Chord Chord A in meters D
3x4 3x4 3x4
3x3 3x3 3x4
3x4 3x4 3x4
3x4 3x4 3x4
3x4 3x4 3x4 3x4 4x4 4x4
10M SPAN
3x4 3x4 3x4
9M SPAN
3x3 3x3 3x3·. 3x4 3x3 3x4
8M SPAN
Diagonal B c
3x3 4x4 4x4
3x4 3x4 3x4
3x4 3x4 3x4
0
12 mm 12 mm 12mm 16 mm 12mm 16mm
12 mm 12 mm 12mm 16mm 12 mm 16mm
12 mm 12 mm 12mm 12mm 12 mm 16mm
z
16mm 19mm 19mm 22mm 19mm 22mm
19mm 19mm 19mm 22mm 19 mm 22mm
16mm 16 mm 19mm 19mm 19mm 22mm
y X Diameter
Vertical
w
CHAPTER
12
ROOF AND ROOFING MATERIALS 12- 1 ROOFING MATERIALS The term roof used here means the top covering of a building that serves as a protective covering from the weather. Likewise. roofing materials refers to the kind of materials used in the construction of the roof. There are numerous forms of roofing which are classified according to the materials used:
l. 2. 3. 4.
Fiber Wood Metal Slate
5. Tiles 6. Reinforced Concrete 7. Plastics 8. Fiberglass
A Ftblr Roofing- Is a cheap kind of materials used for roofing made out of tar felt or other materials, available in rolls made in several varieties. Fiber roofing is laid on·an undersurface made of tongue and groove (T & G) wood board preferably well-seasoned or kiln-dried to prevent warping and splitting of wood due to alternating temperature that causes tearing of the fiber. Laying Procedure - The laying procedures in fastening fiber roofing sheets are as follows: Lay the T & G board on the roof frame as undersheating well fastened by 8d common wire nails. b. Mark the roofing surface with chalkline to insure a untform laps and parallel widths in laying the fiber .materials. c. Use galvanized nails with large head but short enough to avoid penetration on the undersurface board. d. Provide 15 em overlap and have it cemented . with coal a.
tar. e. Do not pull a strip of roofing paper after it was unrolled straight at the start of the work. B Canvas Roofing - Is extensively used for deck roofing of boats, cars, garage or shed etc. Canvas are usually treated .with 242
linseed oil and followed with a ~oat of paint 1fter laying or maybe retreated with linseed oil after laying then fQIIowed by paint.
Laying Procedure: -
1. Before laying, canvas should be dampened and drawn evenly taut, raw edges are concealed and nailed with 2 em galvanized or copper tacks spaced at 2 em. apart. 2. One way of treating canvas is to apply a heavy coat of raw linseed oil and allow to saturate, while it is still wet, sprinkle all over with calcined plaster of paris evenly spread with brush, thus removing superf uous plaster This procedure prevents the contraction and expansion of the canvas and at the same time increase the wear resistance and provide a durable base for paint. C - Wood Shing1es: - Is not popular and is not being used in the Philippines although wood of the best quality are found in·the entire archipelago. · D - Slate Roofing: - Is not recommended on roof of wooden houses, because any vibration will readily crack off the shingles if nailed rigidly or cemented .. E - Metal Roofing: - The materials used under this category are classified as follows:
1. Galvanized Iron 2. Aluminum 3. Tin {Terne .Plate) 4. Titanium Copper Zinc Alloy
5. 6. 7. 8.
Copper Copper Bearing Steel Stainless Steel Lead with 4% to 6% antimony
12-2 GALVANIZED IRON SHEETS Galvanized iron roofing is either plain or corrugated. The thickness are measured in terms of "Gauge" from numbers 14 to 30. The sheet becomes thinner as the gauge number increases. for instance. gauge 20 is thinner than gauge 18. The prices of G.l. sheets varies per unit length depending upon the thickness. The gauge number 26 is the most commonly use<.l for roof ing
243
1
although No. 24 is sometimes specified by those who could afford the cost. Statisticelly, most of the technocrats and laymen coosumers have inadequate knowledge of how to dJstlnguish the difference in thickness of G. I. sheets between the consecutive gauges 'kay, 24, 25, 26. to 30 which is difficult even with the aid of a caliper since thickness will be measured in terms of hundreths or thouunths of a centimeter. This is a matter of interest that one should kndW in buying G. I. sheet because ~t is most likety to happen that one is g;ven gauge 28 or 30 instead of the gauge 26 that was ordered and bought from the supplier. Be it accidentally or Intentionally done, it is to the disadvantage of the buyer In terms of cost and quality of the materials. The only way by which one could be sure of the right quaHty required is by 'weight measure of the sheets which is presented in the following Table. It would be logical to pay higher and obtain the right gauge than pay lower without knowing that a th inner and poorer quality.roofing sheet is obtained.
Corrupted G.l. Sheet: Figure 12- 1 Among the metal roofing enumerated, galvanized iron sheet is the most popular and commonly specified considering the advantages that it offers to the builders and homeowners. The standard commercial size width is (32" ) .80m with length that ranges from (5 to 12') ' 1.50 to 3.60 m. Longer spans are also available through special order and arrangement. Corrugated G.l. sheet' is the most common and extensively used roofing materials for residential, commercial; religious as well as industrial buildings. The popularity of galvanized roofing is brought about by the advantages it offers such as cost. availability, durability and ease of installation.·
~
~
14 15 16 17 . 18 19 20 .21 22 23 24 2,5 26 27 28 29 30
.041
.203 .180 1.63 .147 .132 . 117 .102 .094 .086 . .079 .071 .064 .056 .051 .048 .043
.58 .53 .47 .41 .38 .35 .33 .30
.64
1.49 1.35 1.21 1.10 .98 .87 .75 .69
GAGE Thickness Weight per ft. (em.)
1.80 (6') 26.84 24.30 21.76 19. 72 17.67 15.63 13.58 12.52 11.54 9.49 9.49 8.43 7.41 6.90 6.39 5.88 . 5.27
1.50 (5')
22.36 20.25 18.14 16.43 14.73 13.02 11.32 10.43 9.61 7.91 7.91 7.02 6.18 5.75 5.32 4.90 4.47 31.31 28.25 25.39 23.00 20.62 18.23 15.84 14.60 13.46 11.07 11.07 9.83 9.88 8.05 7.45 6.86 6.62
2.10 (7') 35.78 32.40 29.02 26.29 23.56 20.84 18.11 16.69 15.38 12.65 12.65 11.24 11.12 9.21 8.52 7.84 7.15
2.40 )8')
3.00 (10') 44.72 40.50 36.27 32.86 29.45 26.05 22.64 20.86 19.23 1,7.45 15.82 14.05 13.59 11.51 10.65 9.80 8 .95
40.26 36.45 32.64 29.58 26.51 23.44 20.37 18.78 17.30 15.71 14.24 12.64 12.35 10.36 9.58 8.82 8 .05
(9')
2.70 49.20 44.55 39.90 36.15 32.40 28.65 24.90 22.95 21.15 19.20 17.40 15.45 13.85 12.66 11.71 10.78 9.84
3.30 {11')
53.6 7 48.60 43.53 39.44 35.35 31.25 27.16 25.04 23.07 20.95 19.98 . 16.85 14.85 13.81 12.78 11.76 10.73
3.60 (1 2')
TABLE 12- 1 STANDARD WE IGHT OF GALVANIZED IRON SH EET IN KILOGRAMS
/
Plain G~l. Sheet: Plain G.l. sheet commercial standard size is (36" x 8 ft.} .90
x 2.40 m. long; other sizes could be obtained through special order. Plain G. I. sheet is also used for roofing, gutters, flashing, ridge, hip and valley rolls, downspout, and straps for rivetting and many more under the tinsmlthing field, to be discussed in the succeding part of this chapter.
12-3 CORRUGATED G. I. ROOFING FASTENERS Corrugated G.t. Sheets are fastened to the purlins either by:
1. Rivetting 2. Nailing Riveting: - In the process of riveting, what is required are plain G.I. straps, G .I. rivets, lead washers and G.l . washers. The G.l. strap is folded 3 em at one end then a hole is punched therein using a nail set with one rivet and G.l. washer inserted inside the hole of the strap then punched to hold in position. In the process of the final riveting, two tinsmiths do the job, one underneath the roof and the other on top of the roof who does the punching setting in the lead washers on the rivets followed by the G. I. washer then the final riveting by the use of ball hammer. The straps are then nailed on the purl ins for final anchorage of the roofing sheets.
Figure 12-2 Nailing)- Fastening of G.i. sheets by nail is the simplest and' most economical method where G. I. roofings are anchored to the • purlins by the use of Roof Nails and a pair of G.l. and lead washer. 246
12-4 ADVANTAGESANDDISADVANTAGESOFG.l. RIVETS
Adv1nt1ge1: 1. Rigidity - The entire roofing acts as one solid covering on top the roof frame with all parts connected by rivets and washers. 2. flexibility - The anchorage on the purlins by G.l. straps allow free movement of the materials brought about by the thermal expansion and contraction.
of
Disadvantages: 1. Expensive - due to the various accessories involved aside from the high cost of labor 2. Difficulty of repair or replacement of defective parts which include dismantling of the ceiling underneath to give access to the tinsmithing activities. 3. Statistically, ' roof damage caused by typhoon are mostly of the rivetted types. Any portion of the roof tha.t fails and give way during typhoon is subjected to maximum exposure to wind pressure. Other parts of the roof structure are affected that usually results to a total destruction of the entire roof including the roof framework. 12-5 ADVANTAGES AND DISADVANTAGES OF G.l. NAILS
Advantages: 1. Economical because only nail and washers are involved. G.l. straps are totally eliminated and the labor cost is substan· tially small. 2. Easy to repair or replace aefective parts without neces· sarily affecting other parts of the building. · · 3. Failure of roof in case of typhoon will 1'\0t result to total damage of the entire roof and framing structure because roofing sheets usually blows up one at a time without being rotted entirely affecting the whole structure. Roofing sheets blown up by wind will not be totally damaged and could be returned to its original position immediately after the calamity.
?47
DisadvantageS - : 1. Wat'er might leak into the nails if not provided with roof cement during the fastening operation or when not pro· perly driven down to attain rigid anchorage onthe purlins. 2. Loose nalls allow roof-play and movement which usually invite water to penetrate into the holes. This usually happens if nails missed the purlins and not corrected at once.
12-6 TECHNICAL SPECIFICATIONS: 1. Corrugated G. I. sheets shall extend not less than 8 em beyond the outer face of the facia board. 2. Nails or Rivets shall be spaced at every other corrugation along the gutter line, end lapping joints, ridge, hip and valley rolls. Other's at every after two corrugations. 3. Nails shall be driven enough to hold the sheet firm to the purlins. too tight might deform the corrugation: too loose will cause movement that might cause water to leak. Avoid · mishitting the purlins in driving nails. Always provide string across the laid roofing sheet to insure the center fastening of • nails to the purlins. · 4. Always provide with string along the gutter I ine where to start th e laying of roofing sheets to avoid misallignment of corrugation of the.succeeding sheets.
Figure 12
Lapping: - In laying corrugated G. I. roofing sheets, there are two kinds of lapping involved:
1. Side Lapping which is either ll/2 or 21/z corrugations 2. End Lappmg which ranges from 20 em to 30 em depending upon the slope of the roof and the number of sheet in a longitudinal row. As previously mentioned, the side lapping is also affected by the above factors but the plan and specifications shall govern.
248
CommiM: Different menufacturers of corrugated G. I. sheet has their own standard mould of corrugations that differ from each other. It is therefore suggested that In specifying or buying roofing sheets always specify one brand throughout to avoid misalignment of corrugations and unfitted end joints of the roof. TABLE 12- 2
ROOF ACCESSORIES AND NUMBER PER Kl LOG RAM
MATERIALS
NUMBER OF PIECES
Galvanized Roofing Nails Lead Washers Galvanized Washers Galvanized Rivets
102
75 126
180
,.. Quantity may vary a .little for different brand TABLE 12-3 SIZES OF G.l. STRAP Size of PurHns {In) {em.)
2x2
5x8
2 X 4 5 X 10 2 X 5 5 X 12 2X6
5 X 15
Strap Dimensions (em)
2.5 X 23 2.5 X 25
2.5 X 28 2.5 X 30
12- 7 PLAIN G.l. SHEET Plain G.l. sheet has numerous uses In roof construction aside from the countless projects of tinsmithlng work. in building construction, plain G. I. sheet could be used as:
1. Gutter 2. Flashing 3. Ridge rolf 4. Hip Roll 5. Valley Roll
6. Anchor Strap 7. Downspout 8. Roofing 9. Water Proofing-sheating
249
Roof Gutter: Roof gutter using galvanized sheet usually specify gauge No. 24. Gutter is either concealed or exposed type In various forms and designs. It runs level in appearance but should be sloped at 5 mm per meter run for effective drainage. G. I. gutter as much as possible should be free from stagnant water and shaH be well maintained with paint or rust protective coating. -
Outl e r$
P ur lin 5 ---\-W\l..f.......,-" -
r o.c i a
Ex posed type
Concealed type Figure 12-4
Flashing: Flashing makes intersections and other exposed parts of the house watertight. It provides a smooth boarder line giving beauty to the structure considering the unlimited variety of designs. Ploin G.l. FIOS ~ ln9
f
oot oc i o
Figure 12-5
Ridge and Hip Roll . Ridge and hip rolls are unlikely to leak because of the slope that water tends to slide down. Because of its prominency in the structure, it is important to have it well done.
Figure 12-6 ·
250
Valley Roll It is always concealed underneath between the intersecting angles of the roof. The design is limited to a semi-circular. U-~hape or square type. This portion of the roof needs careful attentcon as the gutter to avoid overflow or leak of water that create trouble and embarassment.
.
Figure 12- 7 Downspout: Downspout conveys the water from the gutter down to the storm drain. Spout is either circular, square or rectangular cross section or othl:!r geometrical form to suit the taste of the designer. The size and location of the downspout is sometimes o matter of hit and miss discretion of the builder. He would not usually waste time to determine the accumulated rain water in the roof, its flow inside the gutter and the required size of the downspout th<,tt will convey the water down the drainage system. The most common size of G.l downspout being used is the (2 ..x4") 5 x 10 em ready made commercial standard. For residential work allow 6 square centimeters downspout for every 10 square meter roof area with a minimun spacing of 6 meters apart and a maximum distance of 15 meters.
Comments and Observation: In the field of actual construction work, it will be noted that after the roof tinsmithing job, there are so many wastes of scrap G. I. sheets. These are the result of indiscriminate and careless cutting of plain G.l. sheet by the tinsmith due to lack
251
of foresight and planning of the work. These waste could have been avoided if the cutting process were done from the largest to the smallest piece of the accessories.The procedures and manner of cutting G. I. sheet shall be as follows:
1. Prepare and cut into actuat sizes the gutter, hip valley and ridge roll in accordance with the plan including the number of pieces needed. Install them to their positions. 2. Layout the corrugated roof and make the necessary diagonal cutting if there is any along the hip and valley roll. 3. Prepare and cut the flashing into 1ctual sizes and have it moulded to its design form. Include in this preparation the cut for the proposed downspout. 4. All the excesses from the above cuttingshal l be made into small straps for riveting. Should it be inadequate, additional cutting could be made out from the stock of plain G.l. sheets. This will avoid excess or scrap galvanized sheet after the tinsmithing job. .12-8 FLAT, STANDING SEAM AND BATTEN ROOFING The materials which are usually used for this type of roofing are :
1. Copper bearing steel 2. Lead with 4% to 6% antimony 3. Tin (Tierne Plate) 4 . .Titanium Copper 5. Galvantzed sheet 6. Stainless Steel
Gauge 24 Gauge 19-20 Gauge 28 Gauge 24-25 Gauge 26 Gauge· 28-30
SLOPE OF ROOF
s..n of Flat lock -The minimum slope should be 5 em. per meter run.
flat
Standing Seam - The minimum slope should be 15 em. per meter run. A good pitch of the roof is advisable to prevent accumulation of water and dirt in shallow puddles.
252
Flat Seam: The roofing sheets are fastened to the sheating board by cleats providing 3 pieces for every sheet. Two pieces along the larger side and one on the shorter side. Fasten two pieces of 2.5 em. barbed wire nails to each cleat. The cross beams are locked together and soaked well with solder. · The sheets are edged 1 em. fastened to the roof with cleats spaced at 20 em ·apart. The cleats are then locked into the seam and fastened to the roof with nails to each cleats.
(
)
---~
Figure 12-8
Standing Sen Tin Roof: The tin sheets are laid on a tongue and groove sheating or underface board, well seasoned. dry lumber. narrow widths, free from holes and should be even in thickness. A new tin sheet should not be laid over otd tin sheet, rotten shingles or tar roof. The sheets of this type of roofing are assembled together in long length at the top. The cross seams are locked together and are well-soldered. The sheets are laid and fastened with cleats spaced at 30 em apart. One edge of the sheet is turned-up to 3 em at right angle and the cleats are installed. The adjoining edge of the next coarse is turned up 4 em and locked together: then turned over and flattened to a round edge. Solder should sweat into all seams and joints. Roof sheets should be painted underneath before it is laid on the roof sheating board. After laying, clean the surface then apply .the first coat of pafnt. The second coat may be applied after two weeks followed by a third coat after one year.
253
Figure 12-9
Batten Roofing: Is made of plain sheets laid on a tongue and groove board, wellseasoned, thoroughly over-lap and j oint to each other.
Figure 12 - 10 254
12-9 CLAV TILE ROOFING: The different types of clay tile roofings art:
l. Span ish Type 2. Straight Barrel Mission Type 3. Roman Type 4 . Greek Type 5. English lnterloc.king Tiles 6. , French Tiles 7. Shingle Flat Tiles
ePANI.H
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Figure 12- 11 2.55
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lAYING Ol' IIIEilft NOTI TH£ GAN 8ET'Wfi I ll ntE SHIE'TIIF THE lAV· lNG II MtOIIIQ.
ITMIERED LAYJNQ
Figure 1'.2t-12
256
prepainted steel ribbed tray roofing and walltng ,.,, •• " t)'J'I'fll'!) ~A•bW~JI
prepainted steel roofing and welling ftiOGf c..-PJHG
Position lap over support.
-·
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Figure 12·13
257
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258
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CHAPTER
13
STAIRS 13-1 INTRODUCTION Not all carpenters possess the skill in building stairs. To those who have tried to make one have found it to be an art in itself. Many have tried but were frustrated, some made it successful, and others won't dare being afraid of the circumstances involved in case of error. · D if f iculties wi ll be encount ered in trying to frame-up a sta irway if one does not know the uses and ma nipulation of t he "Steel Square". The Steel Square play s a major role in sta irway framing, know its functions and a satisfactory result will be obtained. Before one makes an attempt to build a stairway, it is impor· tant to know and be familiar with the terms used in stair design.
13 - 2 DEFINITIONS: Beluster - A small post supporting the handrail or a coping. Bal,u stnde- A series or row of balusters joined by a handrail or cop ing as the parapet of a balcony. A support"_for winders wedged into the walls secured · by the stringers. · Carriage - That portion which supports the steps of a wooden stairs. Close String- A staircase without open newel in a dog stairs. Cockel Stair- Is a term given to 'a winding staircase. Circular Stair - A staircase with steps wif"!ding in a circle or cylinder. Curve out- A concave curve on the face of a front string. Curtail Step - The first step by wh ich a stair is ascended, terminating at the end in a f orm of a scroll following the plan of a ·handrail. . Elliptical. Stairs - Those ·elliptical in plan where each tread assembly converging in an elliptical ring in plan. Face Mould- A section produced on any enclined plane vertically over a curved plan of a handrail. ' Flight of Stairs - Is the series of steps leading from one land· ing to another. Front String: - The string on the side of stairs where the handra il is placed. 259
Bearen -
Fillet - Is a band fastened to the face of a front string below the curve and extending the width of a tread. Flyers- Steps in a flight that are parallel with each other. Geometrical Stain- Is a flight of a stair supported by the wall at the end of the steps. Half Space - The Interval between two flights of steps in staircase. · Han~rail - A rail ru nning parallel with the inclination of the . stairs that holds the baluster. Hollow Newel - An opening in the middle of the staircase as distinguished from solid newel wherein the ends of steps are attached. Ho..ing - The notches in the string board of a stair for the reception of stairs. Knee- Is the convex bend at the back of the handrail. Unding - Is that horizontal floor as resting place in a flight. . Newel - The central .column where the steps of a circular staircase wind. ··"Nosing - The front edge of the step that project beyond t he riser. Pitching Piece - A horizonta l member one end is wedged into the wall at the top of the flight of stairs that supports the upper end of the rough stringer. Pitch -
The angle of inclination of the horizontal of the stairs. Ramp - A slope surface that rises and twists simultaneously. Rise- The height of a flight of stairs frorn landing to landing. The height between successive treads or stairs. Riser- The vertical face of a stair step. Run - The horizontal distance from the first to the last riser of a stair flight. Sp~ndril- The angle formed by a stairway. Stain - The steps wherein t o ascend or descend from one storey to another. Staircase- Is the whole set of stairs; the structure containing a flight of stairs. Stair Builders Trusss - Crossed beams which support the landing of a stair. Stair Clip - A metal .clip used to hold a stair carpet in place.
260
llllrhlld -
The initial stair at the top of 1 fUght of stair or staircase. · ltllr Headroom - The clear vertical height measured from the nosing of a stair tread to any overhead. obstruction. 8tllr Turret - A building containing a winding stair wh~h usually fills it entirely; A stair enclosure which projects beyond the building roof. Stair well - The vertiCal shaft which contains a staircase. Stn1ight flight of stairs - One having the steps parallel and at right angle to the strings. Steps- The assembly consisting of a tread and a riser. Step - Stair unit which consists of one tread and one riser. Scroll or wrtail l1lp - The bottom step with the front end s1oped to receive. String - The part of a flight of st<:tirs which forms its ceiling or soffit. String Board - The board next to the well hole which receives the ends of the steps. Soffit- The underneath of an arch or moulding. T,_ - The horizontal part of. a step Including the nosing. T,_. length - The d imension of a tread measured perpendi· cular to the normal line of travel on a stair. · · Treld Plate - A metal fabricated floor plate. Treed Return - In an open stair, the continuation of the horizontal rounded edge of the tread beyond the stair ~tringer.
Treed run- The horizontal distance between two consecutive risers or. on an open riser stair, the horizontal distance between nosings or the outer edges of successive treads all measured perpendicular to the front edges of the nosing or tread. Treed Width - The dimensions of a tread plus the projection of the nosing if any. Will String - The board placed against the wall to receive the end of the step. Well- The place occupied by the flight of stairs. W•l Hole- The opening In floor at the top of a flight or stairs. Well Staircase - A winding staircase enclosed by walls resembling a well. Wind. . - Steps not parallel with each other. W.Nth- The whole of a helically curved hand rail. 261
lllf ll. HOL E
fl.OOR
CE ll.. l NG
RUN OF ST(P :II 0 0
cr Q
r"'
SHP
1\\JN
F igure 13· 1 262
13-3 LAYINGOUTOFSTAIRS The method of laying out stairs are:
1. Determine the clear height of the rise in meter. Ordinarily, the rise per step is 17 to 18 em and the minimum tread width is 25 em. 2. Divide the rise (height in meter} by .17 or .18 to determine the number of steps. 3. Divide the run distance in meter by .25 or .30m , 4. If the result.found in step 3 is less than the number found in step 2, the run length has to be extended. 5. There should be no fractional value of a riser. Shoutd there be from the result of step 2, adjust the fractional value in equal proportion to the number of riser height, but in no case shall the rise per step be greater than 19 em or less than 17 c.m otherwise, the stairs will not be an ideal one. It is important to make a cross sectional sketch of a stair before making the final plan layout indicating the number of steps to avoid adjustments of the run during the actual construction. ·
I
o.oe"'.
----------- ... •.. - - - - - - ___ 3·ii
Fl~or 11u/
Agure 13-2 13-4 LAYING OUT THE STRINGER After determining the number of tread and the height per rise of the steps follow the actual marking on the stringer by the aid . of the steel square.
263
the length of the stringer could be determined by either the 2 use of the Pythagorian Formula L = rise + run 2 or by actual measurement using a meter rule or taptr;
Figure 13 - 3
TABLE Number of Step
13~1
HEIGHT OF ·RISE AND LENGHT OF RUN FOR A GIVEN NUMBER OF STEP ···-- -Length ()f Run Height of Rise (In m.) (in m.) Tread
Riser
4 5. 6 7 8 9 10
u
12 13 14 15 16 17
18 19 20 26.4
.68 .85 1.02 1.19 1.36 1.53 1.70 1.87 2;04 2.21 2.38 2.55 . 2.72 2.89 3.06
3.23 3.40
--·-·-····· ...
.72 .90 1.08 1.26
1.44 1.62 1.80 1.98 2.16 2.34 2.52 2.70 2.88 3.06 3.24 3.42 3.60
1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 3.00 3.25 3.50 3.75 4.00 4.25 4.50 4.75 5.00
-. 1.20 1.50 1.80 2.10 2.40 2.70 3.00 3.30 3.60 3.90 4.20 4.50 4.80 5.10 5.40 5.70 6.00
13-5 TYPE OF STRINGERS Thero are several forms of stringers ·classified according to the method of attaching the risers and the treads. l. Cut ·
2. Cleated 3. Built-up 4. Rabbeted (Housed) Cut Stringer - Are popularly employed in most modern and contemporary house design. Cleated Stringer- Is used for a very rough work.
Built·up Stringer - Is employed on the wi
CUT STRING£R
CLEAT£0 STIWHitlt 8lO C Ita Cllt fr
o11tal O• atrlntor
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Figure 13·4 265
Rabbeted Stringer - Is adopted on a fine work and usually made at the mill. The risers and treads are held in the rabbets by wedges set in by glue.
Figure 13·5 13- 6
HANDRAIL AND BALUSTERS
Handrail and balusters have multiplicity of dtslgn and forms made of either wood or metal or the combination of both. In either type and forms the best is prefabricated on tho mill or metal craft for precision of the work to be assembled on site. Handrails that presents difficulty to the carpenter is the curved portion located at the end and the change of flight. These p
structural framework of the building shall be provided. Likewise, if the stair between floor is divided into two or more flights, the intermediate beams should be used to support the intermediate landing. Where conditions permit, the intermediate slab maybe supported directly by the walls of the building. . The Building Code on stairs so requires that · the maximum distance from the farth~st point in the floor area to stairway, the minimum width, the maximum height of any straight flight, the maximum rise of a single step, the minimum distance of the run between the vertical faces of the consecutive steps and the ' required relation of the rise and run shall be designed to give safety and convenience in climbing. The Code further specifies: 1) The minimum width of any stair slab and the minimum dimensions of any landing should be about 1.10 m. 2) The maximum rise of a stair step is usually specified as about 18 em. A rise less than 16 em. is general! not considered satisfactory. 3) The minimum tread width exclusive of the nosing is 25cm. 4) The maximum height of a straight flight between landing is generally 3.60 m. except those serving as an exit from place of assembly where a maximum height of 2.40 m. is normally spe· cified. 5) The number of stairway is governed by the number of probable occupants per floor, width of stairway and the building floor area. The distance from any point in an open floor area to the nearest stairway shall not exceed 30 meters and that the corresponding distance along corridors in a particular area shall not exceed 38 meters.
6) The combined width of all the stairway in any floor shall accommodate at one time the total number of persons occupying the largest floor area under the condition that ~ne person for each .33 sq. m. floor area on the landing and halls within the stairway enclosure. 7) In buildings of more than 12 meters height and in all · mercantile buildings regardless of height, the required stairways
267
must be completely enclosed by fireproof partitjons and at least one stajrway shall continue to the roof. The actual construction of stairways are usually boilt after the completion of the main structural framework in which case recesses should be left on the beam to support the stair slab including the provision of dowels in preparation for the necessary anchorage. The steps of the stairways are usually poured monolithically with the floor slab. ' Construction of reinforced concrete stairway is done from an actual pattern made of plywood or other forms fixed on the site to a rigid position supported by scaffolding or staging•
•
268
CHAPTER
14
PRECAST AND PRESTRESSED CONSTRUCTION 14 - 1 .INTRODUCTION The introduction of precast-concrete construction was brought about by building costs that has considerably increased faster than most industrial products that are affected by the large amount of on-site labor il1volved in the traditional methods of construction. The demand for skilled workers on on-site building cons-truction is increasingly outrunning the supply. The answer to these problems· were brought about by the industrialization of construction and substitution of site labor by factory produced precast concrete structure which has rapidly developed and gained importance. The advantages of precast construction are achieved by massproduction of standardized and repetitive units. less labor cost per piece due to mechanized series of productions, use of unskilled labor, less construction time, better quality control and higher strength of concrete and construction free from the effects of weather conditions.
14-2 TYPES OF PRECAST STRUCTURE Wall Panels - This type of precast structure has numerous designs depending upon the architectural. requirements. The common. shapes produced for one to four story high structures are sections having a width up to 2.40 m. They are used as curtain walls attached to columns and beams or sometimes as bearing walls. The different types of wall panels are:
1. Flat Type 2. Double Tee Tyoe
3. Ribbed Type 4. Window or Mullion Type
To improve the therm~t insulation of the panel, foam glass, glass fiber or expanded plastic is inserted between two layers of lightweight concrete adequately bonded interconnecting the two layers to act as one unit. Stresses in handling and erection of the ·member is more than that of the finished field structure, hence, control of cracking is of great importance.
269
' +a+ewi
'I''P
3 ·
2
Figure 14-1 14- 3 ROOF AND FLOOR MEMBERS Roof and f loor members are made in w ide variety to su it the different conditions such as span, magnitude of load, fire ratings and appearance.
1.11 0-2. 40111 .
• $S~5'"'·
.eo·.• "'· .2)
Flat slab
Hollow plan~
Double Tee
Single Tee
Figure 14-2
Flat Slab - Is usually 10 em thick but sometimes as th in as 7 em when used on a continuous several span having a width that ranges from 1.20 m to 2.40 m with a length up to 11.00 meters. 270
Hollow Plink - Is a lightweight member that covers a longer span made by extrusion Jn speciat machine with a thickness that ranges from 10 em to 20 em and the width ranges from .60 to 1.20 m used on roof having a span from 5.00 m to 10.00 m and also on floor with 3.50 to 7.00 m span which could be augmented to 9.00 m when 5 em topping is applied to act monolithically with the hollow plank. Double Tee- Are the most widely used shapes for longer span having a depth from 4.00 to 6.50 m generally used on roof having a span up to 18 m when a topping of at least 5 .em is applied to act monolithically with the precast members. It could be used on floor to a span up to 15 meters depending upon the load and deflection ·requirements. Single Tee - Are used for roofing having a span up to 30 meters and more. The flange of the Tee constitute the floor or roof slab. 14- 4 PRECAST BEAMS The shape of precast beams depends upon the manner of framing. The various shapes are:
1. Rectangular Beam - Where the floor and roof members are supported on top of the beam. 2. Ledger Beam - Is designed to reduce the height of the floor and roof construction.
3. L·a.m - To provide bearing, the beam is designed in
a form of L.
;
4. AASHTO Bridge Girder - Named after the American Association of State Highway and Transportation Officials.
Figure 14-3 271
·14- 5 PRECAST COLUMN Precast column sizes are from .30 x .30m to .60 x .60 meters. In a multi-story construction, the columns are made continuous up to four stories where in corbels are used to provide bearing for the beam. Tee column is sometimes used to support directly double Tee floor members without tlie use of intermediate members.
Column· bas e c onne c t i ons
column
.Preca3 1 Columnr..
Figure 14- 4
C orbel
Corbel
14 - 6 PRESTRESSED CONCRETE The early concept of prestressing was suggested by P.H. Jackson and G.R. Steiner of USA, J. Manli of Austria and J. Koenen of Germany between the year 1886 and 1908. The use of high strength steel wss through the suggestion of F Von Emperger of Austria in 1923 followed by R.H. Dell of USA who proposed full prestressing to eliminate cracks completely but their ideas only ended on papers. The practical development of prestressed concrete was accredited to E. Freesivet and Y. Guyon of France, E. Hoyer of Germany and G. Magnet of Belgium. In 1923 W.H. Hewitt has originated the circular prestressing of cylindrical tank and pipes followed by the important contributions made by T.Y. Lin in the design of many types of prestressed concrete structure in the United States since the year 1950. 272
14- 7 PRESTRESSING OF CONCRETE There are several methods employed in applying prestressed force to a concrete beam; 1. Precompressing Method reacting against abutment.
Is a proce$s of using jacks
f4-8-rom-::,----~Ab~~~') Figure
1~5
2. Self-Contained Method - The process is done by tying the jack base together with wires or cables located on each side of the beam. Usually the wires and cables are pressed through a hollow conduit embedded in the concrete beam, One end of the tendon is anchored and forces are applied at the other end. After attaining the desired prestress force. the tendon is then ·wedged against the concrete, removing the jack equipment.
Figure
1~6
3. Bond Friction ·- The prestressing s;rands are stretched between massive abutment prior to casting of concrete in the beam· forms. After the concrete has gained sufficient strength, the jacks are then released transferring the prestressed force to ·the concrete by bond and friction along the strands.
27.3
t
4.. Th.,aJ Prestressing -The steel is preheated by means of electric power which are anchored against the opposite end of the concrete beam. The cooling process produces prestress force through restrained contraction. ·
Anchorooe
CGIMe=
~;--~--------s; O..m-=:,
Figure 14-7
~"
'
5. Volumetric Expansion - The use of expanding cement restrained by the steel strand or by a fixed abutments produces prestressed force. The Self Contained and the Bond and Friction methods can generally be .classified as pre-tensioning or post-tensioning system. These methods can be applied to mass production of casting several meters long of structure and cutting the individual beam . or post to the desired length out from the.long casting. The .failure of early attempt In prestressing concrete was due to the use of ordinary steel having low prestress strength capa· bility which was rapidly lost due to shrinkage and creep in the concrete. Prestressing of concrete could be effective when a very high strength steel are used. Experiments show that high strength has only about 15% stress loss as compared to 100% loss in a beam using ordinary steel. Prestressing steel is usually in the forrn of individual wire strand cable made up of seven wires and alloy steel bars.
t.HE CAUSES OF PRESTRESS LOSSES ARE:
1. 2. 3. 4. 5. 6.
Slip at Anchorage Elastic shortening of concrete Creep of concrete Shrinkage of Concrete Relaxation of steel stress Frictional foss due to intended or unintended curvature in the tendons. 27<4
14- 8 CONCRETE FOR PRESTRESSING Concrete of higher compressive strength Is ultd for prestressed structures. Most of the prestressed construction specify a com· pressive strenath of concrete between (4,000 to 6,000 psi) 280-4.'?2 kg/em:~ becau;;t~ of the following advantages that it offers. a) High strength concrete has a higher moduius of elasticity. It minimize the reduction of prestress loss. b) Increasing the compressive strength of the concrete meets the problem of high bearing stresses at the ends of post and beam where the prestressing force is transferred from the tendon to the anchorage dowels which directly bears against the concrete. c} High strength concrete develops stronger bond prestresses to pretensioning construction. d) High strength concrete gives higher strength to precast construction when curing is carefully controlled.
14- 9 SHAPE OF PRESTRESSED STRUCTURE The common shapes .of prestressed structural members are:
1. Double TEE - Is considered as the most widely used section for prestressed construction with a flat surface having a width that ranges from 1.20 to 2.40 'meters wide. The thickness depends upon the requirements while the span can extend up to 18 meters.
iT Figure 14·9 2. Single TEE - Is normally used for longer span up to 36 ·meters with heavier loads. ·
275
cg
Figure 14-10
3. f·Sectlon -· Is widely used for bridges. roof, girders up to 36 meters span.
Figure 14-11
4, Channel Slab- Is used for floors in the intermediate span.
lf: .. ·
::::::::{{:-:::::~
..
.·:-. . ·.·
Figure 14-12
5. BoK Girder -
Is used on bridges of intermediate and
major span.
Figure 14-13 276
lnwr1ed T• s.:tion - Provides a bearing ledge to carry the precut deck members having a perpendiculer direction of span.
Figure 14-14
TABLE 14-1 AREAS, STRENGTH AND INITIAL TENSIONING LOAD FOR PRESTRESSING STEEL Miru'"''~~"'
,...,il,
•lrtJt,C~
Tw•
/,... bi
Gr-M•25o
Ultimate
lr.iliol
NorniMl
•trtrt{,tll
ltlllicm
diomtlcr, ill.
orto,
A~.f~··
0.70A_./,.,
in.'
lip•
kip•
0.250 0.313 0 .375 0.437. 0.500
0 .0356 0 .0578 0 .0799 0.1089
8 .9 14.5 20 .0 27 .2 36 .0
&.2 1Q. 2
0.250 0 313 0 .375 0.437 0.500
0.0356 0 .0578 0 .0799 0 . 1089 0 . 1(38
29 .4 38 .8 .
0 .0290 0 .0598
7.25 14 .05
NoJtli~te~l
250
MYeD-wire mud
. 270
Gr-270 MVIlfl·wire
etrand
'
O.IU8
Strea--reliend 10lid wire
250 235
0 . 192
AJloy•teel baN
145
0.750 0.875 1.000 1.125 1.250 1.375
0 .442 0 .601 0 .7M 0 .994
0. 7.5(1
AUDy«eel
1&0
ban (•peeial)
0.276
0.875 1.000
1.125 1.250 1.375 -
9.6 15.6 21 .6
u..o . 19 .0 25.2
6.7 10.9 15.1 20.6 27 .2
5.08 9.84
64
46
87 114
61 80
1.227
Iff 178
101 125
1. 485'
215
15f
0 ...2 0 .601 0.785 0 .994 1.:127. 1.485
71
50 67 88
~
126
159 196
238
111 137 167
277
. , ,....... li.S.a~a~
NOI'Irinal .,..,
NOIIIillll diuwtet, tile In Bar
.. ' l
...
O.t1
'
to
LOO
),~
1.27 1.$6 2.25 4.00
4.303 .5..313 7.65G 13.600
0.31 0.44
011.5 1.000 I.IZI 1.270
0.60
1.410
II 14 II
0.79
0.376 0.668 1.043 1.»2 2.044 2.670
0.20
G.W 0.7,.
6 7 I
Nomillal wcitht, lb/fl
la 3
.0.37.5
U'J
2.m
SJ Nominzl.
Nominal
Nominal
diameter.
111ea,
mass,
mm
mm'
ki/m
71 129
9.S2.S 12.700 13.87.5 19.050 22.223 25.400 2!.651 32.251 3.5.814 43.00';' .57.328
O.S60 0.994 U.52 2.23.5
200 2&t 387 SIO 645
3.042 3.973 .5,060
119
6,-404 7.907
1,()06 1,452 2,-'111
11.385
20.2'"1
WlnnW.-a Sl
U.S. Cutonwy
w.-osize
Nomistal
Nominal
diameter,
area.
NOC!Iint.' wcjpt,
Jl:ominal
Nominal
N0t11inal
dialheter,
area.
mAll.
in
mz
lb/ft
mm
mmz
kt/m
Dll
0/slS
0.310
0.618
O.JOO 0.280
1.0$4 I.C)lO
15.951 15.(6'1
wu
200.0 193.6 110.7 167.7
1.'69
D.JO DJ:8 D26 Dl4
W22 W20
Dlll
s-odt Deformed
Wll W10 W'lll W26
WII
W16 Wl4 Wll Wit WIO.S WIG W5U
W9 Wl•.5 WI
wu
·W?
022 018 Dl6 014 012
Dll DID
DP
OASI 0.422 0.390 0.3?4 . 0.366 0.3.56 0.348 0..338
o.m
0.319
rY1 D6
m
W.f
1)1
278
0 ..529 0.504 0.478
O.l09 0.298 0.288
w'
W4.~
0.553
Dl
W6...5 W6 ' WH
0.597 0.57.5
0.276 0.264 0.2-'l 0.240 O.Z:!~
-·-· - -· ...- .
0.260 . 0.240 0.220 0.200 0.180 0.160
0.140 0.120 0.110 0.10.5 0.100 0.051.5 0.0510
o.m
1.5.164
0.934
)4.60$ 14.046 13.437 12.802 12.141 11.45.5 10.719 9.906 9..500
0.816 0.748 0.680 6.612 0 ..544 0.476 6.408 0.374 0.357 0.)40 0.323
,,...
141.9 129.0 116.1 103.2 9().)
n.4
9.296 9.042
7t.O 67.7 64..5
8.8)9
61.J
8.58.5 8.3.57
.58.1 .s4A
0.25.5
8. 103 7.849 7•.569 7.31$ 7.010
"·' ......
0.060
0.238 0.221 O.:!IW
0.0.5.5 0.050 0.04, O.Oo6t
0.187 0.110 0.1$3 0.136
o.oas 0.080 0.01.5 0.0'10 0.06.5
o.J06. 0.219
o.m
!JIB 1.417 1.)90
1.214 1.11J 1.012 0.911 0.810 0.108 0.607 0.$57
o.m
0.~
0.4111 6.4.55 0.430 0.40.5 0.380
4.5.2 41.9
O.J.s4 0.)29
6.706 6.401
38.7 35.5 32.3
0.304 0.278
6.096 5.115
29.0 25.8
0.253 0.22~
0.2(\"
MITAI. RIINPORCIMINT
TABLF. .14 2
w. ........... U.S.cutc.mary No111inaJ
'WIIIId Dll.ll
diuwler,
SIIIOOth Deformed
in
W3..5 W.l W2.9 W2..5 W2
Ull
O. I.M 0. 192 0.178 0.159 O.tl.5
W\.4
-·
NOIII6MI
ia
1
0.0» 0.0)0 O.Gl!J 0,025 0.020 0.014
...... N-l"'l
Sl No111inaJ
Nominal
No111inal
dilflleter
lttl,
IIIUS.
.nunz
q.lm
,,_.
0.177 0.152 0.146 0.127 0.101 0.073
"''"
111111
o.oas
4 ..'21 4,0)9
·16.1
.}.429
9.0
Ul9 0.102 0.0!11
0.061 OJNt
..... ........
.5.)59 4.9S) 4.877
U.S.. cullloaWy
22.6 18.7 12.9
Sl
NCIGiiul
Nominal
NoaUu1
NoaUMI
NonriJIII
diMietef,
II'U,
ditalctec.
Type
ill
in 1
'!~~daM.
lb/fl
mm
area. mm'
Seveo-win strand
o.m
0.250 .
0.4)6 O.OSI
0.12 0.10
$1Jaftd (Grade 2?0}
Prnttetatftl wire
PrestreHU..
lws (smooth)
•
%3.2
t .l19
37.4 .51.6 69.7 92.9
0.402 0•.5.51
IJU
UOJ
o:21
0.101
0.)7
0.144 0.216
OAt 0.74
0.01.5 0.11.5
0.~
0.15)
0.600
0.215
0.29 0.40 0..5.} 0.74
9.52.5 11.125 12.700 15.2«1
.54.8 74.2 98.7 ll8.7
O..Ul
0.4l8
0.192 0.196 0.2'0 0.%76
0.029 0.0)0 0.049 0.060
0.098 0.10 0.17 0.20
4.877 4.978 6.)$0 7.010
18.7 19.4 :H.6 31.7
0.146 0.149
0.44 0.60 0.78 0.99 1.23
1.$0 2.04 2.67
19.0$0 22.22.5 2.5.-Q} 21.$7.5 31.750 34.925
283.9 )17.1
2.231
l7
• I
,, I! ,,
Prestressina
bus ((lefonntd)
q.t,.
o.oao
o.soo· uoo o.:m
Seven-wire
NCIIIIiaal
6.3-'0 7.9-'0 9•.525 11.125 12J'il0 U.240
0.37.5 0.431
(Onldc HO)
......
I
IJ
tl
l ,q
0.21 0.42 0.15 1.25 1..56
).)1
4.17 .5.0.5 0.98 1.49
1.5.875 19.0-'0
3.01 4.39 .5•.56
31.7-'0 34.92.5
2.5.400
u•
o.m
0..59.5 0.789 1.101
0.25)
0.2518 ),0)6
J.m
-'03.2 631.7
'-030
79).5 954.1
7•.51.5
110.6 271.0 548.4 106•.5 1006..5
6.206
1.4.18 2.217 4AO 6.535 8.274
279
!
14 - 10 ·. METAL REINFORCEMENT: The ACI Code-on metal reinforcement for prestressed con crete so provides: "Wire and strand for tendons in prestressed concrete shall. conform to the specifications for Uncoated Seven·Wire Stress-Relieved Strand for prest ressed concrete" · (ASTM A416) or specifications for Uncoated Stress--Relieved Wire for Prestressed Concrete" ASTM A421). Strand or wire not specifically itemized in ASTM A416 or A421 may be used provided that they conform to the minium requirements of these specifications and have no properties which make them less satisfactory than those listed in ASTM A416 or A421." "High strength alloy steel bars for post tensioning tendons shall be proof·stressed during manufacture to 85 percent of the minimum guaranteed tensile strength. After proof-stressing, bars shall be subj ected to a stress relieving heat treatment to produce the prescribed physical properties. After processing, the physical properties of the bars when tested on full sections, shall conform to the follow ing min imum properties: Yield strength (0.2 percent offset) . Elongation at rupture in 20 diameters: Reduction of Area at rupture:·
0.85%
4% 200/o
Minimum Bonded reinforcement requirements - "Some bonded re inforcement shall be provided in the precompressed tension zone of flexural members where the prestressing steel is unbonded. Such bonded reinforcement shall be distributed uni-· formly over the tension zone near the extreme tension fiber. The minimum amount of bonded reinforcement As in beams and one-way slabs shall be or As = 0. 004A wh ichever is larger, where A '"' area of that part of t he cross section between the flexural tension face and the center of gravity of the gross section and Nc = ~ensile force in the concrete under load of D + 1.2L and fv shall nqt exceed 60,ooo· psi or 413700 kPa."
280
End region•- "Reinforcement shall be provided when required in the anchorage zone to resist bursting, h()rizontal split· ting, and spalling forces induced by the tendon anchorages. Regions of abrupt change in section shall be adequately reinforced. End blocks shall be provided when required for end bearing or for distribution of concentrated prestressing forces. Post-tensioning anchorages and the supporting concrete shall be designed to support the maximum jacking load at the concrete strength at time of prestressing and the end anchorage region shalt be designed to develop the guaranteed ultimate tensile strength of the tendons... Continuous beans- "Shall be designed for adequate strength and satisfactory behavior. Behavior shall be determined by elastic analysis, taking into account the reactions, moments, shears, and axial forces produced by prestressing, the effects of temperature, creep, shrinkage, axial deformation, restrain of attached structural elements, and foundation settlement."
Compression members-Combined axial load and bending.. Pr.estressed concrete members under combined axial load and bending,With or without nonprest.ressed reinforcement, shall be proportioned by the strength design methods for members without prestressing. The effects of prestress, shrinkage. and creep shall also be included. The miniumum amounts of reinforcement specified may be waived where average prestress is over 225 psi or 1551 kPa and a structural analysis shows adequate strength and stability. Lateral reinforcement excapt for walls ...... All prestressing steel shall be enclosed by spirals or closed lateral ties at least 10 mm diameter in size. The spacing of the ties shall not exceed 48 times the tie diameters, o.r the least dimension of the column. Ties shall be located vertically not more ttian one-half a tie spacing above the floor or footing, and shall be spaced as provided herein to not more than one-half a tie spacing below the lowest horizontal reinforcement in the slab or drop panel above. Where beams or brackets provide enClosure on all sides of the column, the ties may be terminated not more than 7cm below the lowest rein· forcement in such beams or brackets. 281
Corrosion protection for unbonded tendons - "Unbonded tendons shal l be completely coated with suitable material to in5Ure corrosion protection. Wrapping must be continuous over the entire zone to be unbonded, and shall prevent intrusion or cement paste or the loss of coating materials during casting operations." "Burning or welding operations in the vicinity of prestressing steel shall be carefully performed so that the prestressing steel shall not be subject to excessive temperatures, welding sparks or ground currents." 14 - 11
GROUT FOR BONDED TENDONS
The ACI code on grout for bonded tendons specif ies: "Grout shall consist of portland cement and potable water., or portland cement, sand and potable water. Suitable admixtures known to have no injurious effects on the steel or the concrete may be used to ·increase workability and to reduce bleeding and shrinkage. Calcium chloride shall not be used. Sand if used shall conform to Specifications for Aggregate for Masonry Mortar except that gradation may be mod ified as necessary to obta in increased workabil it y. The proportioning of the grouting materials shall be based on the results of the tests on fresh and hardened grout prior to beginning work. The water content shall be minimum necessary for proper placement but in no case be more than 50% the content of cement by weight. Grout shall be mixed in a high speed mechanical mixer and then passed through a strainer into pumping equipment which provides for recirculation. The temperature of members at the time of grollting must be above 32° C and shall be maintained at this temperature for at least 48 hours." Ducts for grouted or unbonded tendons shall be mortar· tight and nonreactive with concrete, tendons or the filler materials. To facilitate grout injection, the inside diameter of the ducts shall be at least 7 mm larger than the diameter of the posttensioning tendon o.r large enough to produce an internal area at least twice the gross area of the prestressing steel.
28 2
14- 12
MEASUREMENT OF PRESTRI.INQ PORCE
Prestressing force could be determined by:
1. Measuring the tendon elongation. 2. Either by checking jack pressure on a calibrated gage or load cell or by the use of a calibrated dynamometer. The cause of any· difference in determining the force which exceed 5 percent could be ascertained and corrected. The elongation requirements shall be taken from the average load elongation curves for the steel used. Where force trasmission from the bulk· heads of the pretensioning bed to the concrete is made by flame cutting the steel, the cutting points and cutting sequence shall be predetermined to avoid undesired temporary stresses. Exposed strands are cut near the member to minimize shock to the concrete. The total loss of prestress due to unreplaced broken tendons shall not exceed 2 percent of the total prestress. 14- 13
POST TENSIONING ACHORAGE
The ACI Code on post tensioning anchorages and couplers so provides: ..Anchorages for unbonded tendons and couplers shall develop the specified ultimate capacity of the tendons without exceeding anticipated set. Anchorages for bonded tendons shall develop at least 90 percent of the specified ultimate capacity of the tendons, when tested in an unbonded:condition, without exceeding anticipated set. However, 100 percent of the spec1fied ultimate capacity of the tendons are bonded in the member. Coupler shall be placed in areas approved by the Engineer ond enclosed in housings long enough to permit the necessary movements. Anchorage and end fittings shall be permanently protected against corrosion. The anchor f~ttings for unbonded tendons shall be capable of transferring to the concrete a load equal to the capacity of the tendon under both static and cyclic loading conditions.
283
CHAPTER
1S
FORM ,SCAFFOLDING &·STAGING 15-1 FORM Form is a temporary boarding, sheating or pans used to produce the desired shape and size of concrete. Forms are es sential requirement in concrete construction. Structural members of a building are built-up into its specified dimensions by the use of forms that serves as mould for the mixed concrete. Concrete mixture is generally semi-fluid that reproduces the shape of anything into which it is poured'. Forms should be watertight, rigid, and strong enough to sustain the weight of concrete. It should be simple and economically designed to be removed easily and reassembled without damage to themselves or to the concrete. The factors considered in the selection of forms are:
1. Cost of materials 2. The construction and assembling cost 3. The number of times it could be used. 4. Strength and resistance to pressure and the tear and wear. Wood board and Plywood forms Wood is the most common andwidely used forms in minor or major constructions. The introduction and satisfactory result brought about by plywood forms almost absolutely resulted in the limited used of tongue and groove (T & G) wood board due to the following advantages offered by the laminated wood board.
l. Plywood as form is generally economical both in materials and labor. . 2. Plywood has plain, even surface with uniform thickness. 3. It offers fitted joints, eliminate dressing. planing of the surface which is normal to wooden board forms. 4. The laminated cross-grained of plywood has made the board stronger and free from warping. 5. Plywood is light-weight, handy and fast to work on. 6. Produce · smooth finishe of concrete that sometimes need little or no plastering at all.
284
Mml Forms-· Metal forms are seldom uMd In building construction becauM of the varied designs and shapes of the structures. Althouoh metal forms
are extensively
used on road construction,
It Is also adopted on precast and prestressing plant 11 mould for tho• flat and wider mem~rs such as floor slabt, wells, beams, columns and those that require mass produCtion with similar dimensions that calls for a repetitive use. Metal forms are generally made out of G.l. sheet. or black iron sheet, supported by flat and angle bars designed to be assembled and · Jacked by means of clamp, bolts and nuts etc.
15 - 2
CONSTRUCTION OF FORMS
Concrete weighs about 2,200 to 2,400 kg./m 3 Forms shall be guarded against bulging and sagging failure that occur during the process of pouring. Smatl cracks develop between joints that gradually w i.dens and cause deforma.tion of the structure that reduce the desired strength. Forms shall be substantially strong to resist the weight and horizontal pressure of fresh concrete. The thickness of the form and the sizes of the frame and ribs depends upon t he nature of the structure t o be su pported classified as small, medium or massive structure. Ord inarily, small structure consisting of smal l footings, columns and beam for one or two story building wherein (3/16) - 6 mm. thick plywood is satisfactorily used supported by 2 x 2 wood frame and ribs. Medium size cons1:ructions are those having concrete column, beams, and concrete floor slab generally of 2 to 3 story high. Forms are made out of (lf• or lfz) 6 or 12 mm thick plywood is employed as form supported by 2 x 2 and 2 x 3 wood fr~me and ribs. Those construction having massive structures uses forms of various thickness th!tt range from 6 mm to 19 mm thick plywood ('I• to 314") support.ed by lumber of sizes from 2 x 2 to 2 x 4. The design of the forms depends upon the degree of the work and specifications as to whet thickness is to be used for a certain structure including its frame and sizes. or dimen. sions of supports.
285
The term Cost being the principal consideration in build ing construction connotes that all phases of the work shall be programmed to contribute to the reduction of cost without sacrificing the strength and quality of the work. Form is not an exception to ' this objective,more so that it falls under the category of the major item in building construction that requires substantial appropriation. Form requires frame and ribs. 2 x 2 lumber is widely used for this purpose regardless of the classification of the structure be it small, medium or massive. The resisting capability of the form depends upon the manner how it will be supported by the framework called scaffolding or staging which will be discussed later. There are two types of framing adopted in ma'king plywood form : the longitudinal and the perpendicular rib type. So far, the most economical and preferred one is the longitudinal type because the cutting of lumber is controlled minimizing short pieces and preserving the length for future use. On the contrary. the perpendicular rib type cutting of lumber into short pieces could not be avoided. After the femoval of forms, they finally become waste to be turned into firewood. Plywood torms -
- -2" 2 Frome -
perpendicular ribs
Longitudinal ribs Figure 15-1
Column forms - Square and rectangular colu mn forms consist of two pieces having the same width with that of one side of the column placed opposite to each other which will be closed with another pair of form having wider width usually 10 em. wider than the former. Circular column has only two pieces of semicircular forms usually made of metal sheet supported by wood frame. Forms for column of various geometrical cross sectional shape are cut according to de-sign.
286
'-. -....
Opposltt form tu••d In riQtlt po•ltton foiiOWid bY tl\t
<;n
'· '~J
col/'er
,..
/
Metol "heet ·Wood frome Rectan~ular
Circular
Square
Figure 15·2 Beam Forms - The form of a beam consist of one bottom forn1 having a width of 10 to 15 em. wider than the beam width and a pair of side forms having a width equal the depth of the beam.
'r ) .
~"' ll} "'~.· :1 I
1: ~
'
.
'r I
'
t :;1-=r:] Co)
(o.) BoHoM form -the sne is wi d1h of beam pi ~s 4 in. or
~.
~·· .
. 10111. . 'fj:.::::-~ (b} ~ide cover .i~sto'oled qHer stttiftO the reinforeemenl. It's widfh i$ e quo I tne deptll of tile beam.
:· ., beom . form .J
Figure 15-3 <
15- 3 ERECTION AND SECURING OF FORMS Forms are properly secured in position by means of cleats, braces. twisted tie ·wire, bolts, clamps or nails. Ordinarily for small structure, forms are erected and secured by means of common wire nails not totally driven down leaving a protroding head for pulling off. by the aid of hammer or wrecking bar. Sometimes this method is not sufficient when the structure is massive · that the employment of those above mentioned accessories are necessary to prevent bulging or sagging of the forms.
297
When tie wire is used, they are twisted to tighten the forms and the projecting end are cut when forms are taken down leaving the other portion of the wire embedded inside the concrete. If bolts are used, they maybe greased before the concreting so that they could be driven out of the concrete easiiy when forms are removed. After 24 hours from the time of pouring, the bond of concrete around the bolts are disturbed by merely tapping them with hammer, so that it could be easily withdrawn when forms are removed.
15-4 .WALL FORMS · Wall forms above the ground or f loor level is usually in pa ir strong enough to resist the lateral pressure of concrete. Wall forms should be guarded against bulging which is the usual failure, the most effective way of securing wall form is the use of bolts and knots. Wall form~ are classified as:
1. Continuous 2. Full Unit 3. Layer Unit a) Continuous b) Sectional The layer unit is considered economical as far as the form is concerned, because the same forms are being used on different section although there is delay in the progress of the work and extra cost of labor.
15 - 5 GREASING OF FORMS The purpose of greasing the form is to make the wood water proof, thus preventing absorption of water in the concrete which causes swelling and warping. Grease also prevents adherence of concn~te to the pores of the wood. Crude oil is the cheapest and most satisfactory materials for this purpose. The oil is mixed with No. 40 motor oil proportioned at 1:3 mixture varying according to the temperature where more oil is necessary on warm wuther. Greasing of form should not be done after the steel bars have been:set to its position.
288
.
15- 6 COMPARATIVE ANALYSIS BETWEEN THE T & G
AND PLYWOOD AS FORM This comparative anatysls was made in 1982 when the price of V.. x 4 ' x 8' plywood cost .,.45.00; lb." ·thick at ~85.00 while T & G lumber cost ~.50 per board foot. The analysis could be usefu I even If ttle prices change at any time because prices wiU definitely increase but the quantity of the materials herein presented wilt remain constant. Hence, this will serve as· a guide in determining the recent cost of materials which will be used as forms in your construction whichever is less in cost.
PLYWOOD FORM a) Thickness -liz (12 mm) Width- 4' {1.20 m) Length - 8' (2.40 m) Effective coverage- 2 ..88 sq. m.
b) Cost: Y, plywood@ .,.85.00
48 in. ft. 2 x 2 lumber
T 8t G a)
LUMBER FORM
Thickness :Y." (19 mm) effective width - 3Yz" ( 9 em) Length - 8' (2.40 m) Number of board ft. equivalent to 2.88 sq. m. area of plywood is 40 bd. ft.
b) Cost: 40 bd. ft@ .,.3~50 ""'~140.00 . 52 in. ft. 2 x 2 lumber
Fig 15-41 c) 93 pes 1" cwnaiJ @ .15 o.c. c) 151 pes 2•. (5 em.) cw nail 10-4.. (10 em.) cw nail 18 pes 4" (10 em.) cw nail d) Labor: 2-carpenters to d) Labor: !-carpenter to assemble In 2 hours/ with do the assembling In 1 hr. fitted T & G joir.ts. Fig15-4
289
It will be noted that lk" (12 mm) thick plywood w~s used although 114" (6 mm) thick plywood cold beusedfor the purpose by adding 4 pes 2 x 2 lumber of 2.40 m (8') long, making the ribs closer at 15 em. o.c. Comparatively, the cost of plywood form is much lower than that of the T & G ·board as presented .in the above tabulation using one board plywood. If the construction requires hundreds of plywood form how much would you save from the difference in cost?
15-7 SCAFFOLDING AND STAGING Scaffolding - Is a temporary structure of wooden p~les and planks providing platform for working men to stand on while erecting or repairing the building. It is further defined as a temporary framework for other purposes. ·'
Staging - Is a more substantial framework progressively built~ up as tall buildings rise up. The term staging is applied because it is built-up in stages one story at a t ime. · Numerous accidents in building construction happened because of faulty construction or ihsufficient supports. One tragic incident that happened very recently at the Film Palace in Metro Manila where several lives including the supervising Engineer · · were burried in cement and rubbles whenthe forms and staging swayed and rammed down in total collapse. · Scaffolding or staging is not as· simple as others think of it. It requires special attention, training and experienced men to do the work. The design and construction of these structure should be done by knowledgeable men specially trained and experienced in the field. Accordingly, the primary cause of accidents and failure of framework is brought about by the use of inferior lumber, inadequate supports and braces, nails and others for economy sake. Definitely, out lumber has no place in scaffolding .or staging work if the builder is aware of the value of life and property involved in building construction.
'
Comment11nd Observ1tlon: 1, Lumber intended for temporary structure to support heavy load concrete shall be selected from straight grain, free from shakes or knots and other defects. · 2. Economizing through inadequate supply of materials will endanger the construction work, aside from the increase of labor cost. Adjustment, reworking of forms and its transfer from one place to another causes delay of the construction and destruction of the forms. The recycling of nails is another factor contributory to the delay, cost and waste of materials and sometimes causes failure of the framework. 3. Actual cost records of professional builders and con· tractors show that sufficient supply of framework materials increases the work's efficiency considering the time involved. 4. A carpenter who have started working from the first working day of the week expect to return to his family with his weekly salary. If the materials on the job site are inadequate which he believes will only last for 2 to 3 days, foot dragging work will be applied so that they may work for a week out of the materials available. On the contrary, if the construction materials are sufficient the workers are inspired and the work will be lively. 5. The idea of laying off some workers for the reason of lack of materials may only create demoralization amo'ng the group. Efficiency is affected because ·they are not sure of their work tenure for they might be the next to be laid off anytime for the same reason. 6. Lumber used for scaffolding or staging should not be considered as waste of construCtion. Some could be used on other parts of the building such as joists, studs, nailing strips etc. The excess has resaleable value which could be derived through public auction sale.
Different parts of staging or scaffolding a) b) c) d) e)
Vertical Supporters FoOting Base (as need arises) Ho.rizontal Braces Block or Wedge support Nails 291 .
The 2 x 2 lumber ( 5 x 5 em. ) is the most abused size ot lumber in the construction of forms, scaffolding or staging although 1 x 2 also serves as supplementary braces for parts with less stresses. 2 x 3 and 2 x 4 lumber are also commonly used where massive and heavy load are to be supported. These sizes are usually used with care and leniency because of its cost and the future plan for its reuse on other parts of the building. When and where to use the above dimensions for scaffolding a matter of consideration depending upon the kind of structure to be supported.
is
Generally. the 2 x 2 rough lumber of -good quality can be used as scaffolding or staging for all types of building construct· ion. Its strength and capability to support concrete mixture depends upon the distances and spacing of the vertical. hori· zontal and diagonal braces. The employment of 2 x 3 and 2 x 4 lumber is inevitable where heavy load, height of the structure and spacing of vertical support is a matter of consideration. The combination therefore of the three sizes is ideal and satisfactory for falsework in building construction. Vertical Supporters- Usually there are ·4 pes. for each column to hold the forms rigidly to. its vertical position. The spacing is usually from 1.00 m. to 1.50 m. or more depending upon the size of the column. The spacing of the vertical supporter shall be ... governed or adjusted to the commercial length of lumber of even ·- · length in feet, or, at the intervals of .50 m. which will be the new measure to be adopted under the Sl system.
Horizontal Braces- The horizontal braces should be equally spaced between floor height. Ordinarily, the floor height is 3.00 m. hence the horizontal braces of staging should be limited to 1.00 m. or more depending upon the size of the lumber.
Diagonal Braces- The triangle is the most rigid connections to be applied in framework structure. As much as possible. dia-gonal braces should be extended from the floor to the upper most of horizontal member of the framework in cross or opposite direction. 292
15-8 STAGING FOR REINFORCED CONCRETE BEAM AND IILOOR SLAB Concrete beams are flanked by series of vertical supporters spaced at proportional distances between columns. These vertical supporters are placed in line with the column supporter in both perpendicular directions. Normally they are spaced at a distance not less than 1.00 m. apart. The horizontal braces follows that. established spacing in the column vertical supporter. The Concrete floor slab vertical supporters will just follow the line and flanking ofthat column and beam framework including ·the horizontal and diagonal braces. The staging framework as much as possible shall be so arranged that all vertical and horizontal members should be in line in aU directions. This will facilitate the movement of the workers and the transfer of materials and tools including the ease of checking and verifying the vertical and horizontal position of th~ structure and the rigidity of the framework.
Figure 15-5 The design of formwork includes the following considerations: 1. The rate and method of placing concrete. 2. Construction loads, including vertical, horizontal and impact loads.
3. Special form requirements necessary for the construction of shells, folded plates, domes, architectural concrete, or similar types of elements. The forms for prestressed members shall be constructed to allow movement of the member without damage during the appli· cation of the prestressing force. Construction loads exceeding the dead load plus the live load should not be allowed to be supported on any unshored portion of the structure under construction. Likewise, no construction load shall be supported on, nor any shoring removed from any part · of the structure under construction except when that structure in combination with the remaining framing system has sufficient strength to support safely its own weight and the loads placed .• thereon. The removal of forms shall be done in such a manner as to insure the complete safety of the structure. When the structure as a whole is adequately supported by shores, the removable floor forms, beam and girder sides, column forms, and similar vertical forms . may be removed after 24 hours, provided, that the concrete is sufficiently strong not to be damaged or injured. The supports of prestressed members may be removed when sufficient prestressing has been applied to enable them to carry their own load and other anticipated construction loads.
· 15-9
..
CONDUITS AND PIPES EMBEDDED IN CONCRETE
Electric conduits and other pipes to be incorporated in the concrete structures shall not with their fittings, displace. more than 4 percent of the area of the cross section of a column on which stress is calculated or which is required for fire protection. Sleeves, conduits, or other pipes passing through · floors, walls, or beams shall be of the size and in such location as not to impair significantly the strength of the structure. Such sleeves. conduits, or pipes may be considered as replacing structurally in compression the displaced concrete, provided that they are no.t ex,posed to rusting or other deterioration. are of uncoated or galvanized iron or steel not thinner than standard Schedule 40 steel pipe having a nominal inside diameter not over 5 em and are spaced not less than three diameters on centers. Embedded pipes or conduits, other than those merely passing through, shall
not be larger in outside dimension than one third the thickness of the slab. wall or beam In which they are embedded. nor shaU they be spaced closer than three diameters or widths on center,. nor so located as to Impair significantty the strength ·of the construc:tion. Sleeves, pipes, or conduits of any material not harmful to concrete maybe embedded in the concrete pr-ovided they are not considered as to replace the displaced concrete. Aluminum pipes or conduits shall not be embedded in structural concrete unless effectively coated to prevent aluminum·concrete reaction or electrolythic action between aluminum and steel. Pipes which will contain liquid, gas or vapor may be embedded in structural concrete under the following considerations: a) Pipes and fittings shall.be.designed to resist -the effects of the material pressure and temperature· that will passthrough. b) Pipes and fittings shall be tested as a unit for leaks immediately prior to the concreting' The testing pressure above atmospheric pressure shall be 50 percent in excess of the pressure to which the pipe and fitting may be subjected. The minimum testing pressure shall not be less than 1000 kPa. above atmospheric pressure held for 4 hours with no drop in pressure except that which may be caused by · · · air temperature. c) The temperature of the liquid, gas or vapor that will pass the pipe shall not exceed 132° C. d) The maximum pressure to which any piping or fittings shall be subjected shall be 1380 kPa above atmospheric pressure. e) Pipes carrying liquid, gas, or vapor. except water not ex· ceeding 72° C nor 340 kPa pressure, is to be placed in the pipes only after the concrete has attained its designed strength. · f)· In solid slabs, the piping if not intended for radiant heating or snow melting, should be placed between. the top and bottom reinforcement. g) The concrete covering of the pipes and fittings shall be not. less than 38 mm for concrete surface expos~ to the weather or in contact with the ground, nor 20 mm for 295
concrete surface not exp~~d directly to the ground or weather. h) The piping .,d fitting connections shall be assembled by means of welding, brazing,. sokler-sweating, or other equally satisfactory method. Screw connections shall be prohibited. The piping system shall be fabricated in such a manner that no cutting bending or displacement of the reinforcement from its proper loc1tion is required.
Horl1o~taJ
or
too m.
Figure 5-6
296
broe•• IIPIII OJ .
ern. 'aj:loe l ftQ
CHAPTER
16
IIJISTING EQUIPMENT AND POWE·R TOOLS 16-1 HOIST Hoist is defined as an equipment used to raise or lower heavy articles. In building construction, some form of hoist is almost necessary in placing structural members such as beams, girders, wall frames, slabs, roof trusses and others. Accordingly, hoisting equipment functions effectively through gearing reduction between the·load and the joint at which the power is app lied. · There are several forms of hoist employed by builders which are classified as: 1. With respect to the lifting materials: a. Rope b. Steel Cable c. Chain
2. With respect to the kmd of gearing:
a. b.
Pulley (block and fall) Differential
c.
Spur gear and drum
d. Mounted crane
16-2 DEFINITIONS: The ropes and cordage mechanism falls within the sailor's pro"ince that nautical terminologies are inevitably used under this topic such as: Bend - is the fastening of the rope to one another or to a ring, thimble, etc. Belay- to make fast the end of a tackle fall at the conclusion of a hoisting operation. Bight- is the loose part of a rope between two fixed ends. Haul ·- to heave or pull on a rope. Hitch - fastening of a rope simply by winding it without knotting around some object. Knot- The process of fastening one part of a rope to another part of the same by interlocking then drawing the loops tight. Lay- is to twist strands together as in making a rope. Make fast- securing the loose end of a rope to some fixed object. 297
Mll'line Spike- a long tappered steel used to unlay or separate the rope strands for splicing. Percllled - to wrap with canvas, cloth or leather to resist chafing. Seize- lashing a rope permanently with a small chord. Sen;e - to lash with a chord, wounding tightly and continuously around the object. Splice - To connect rope's ends .together by unlaying each strands then plaiting both up together mak ing one continuous rope. Strand- Two or more layers of yarns twisted together. T..t - Stretched or drawn tight. Yarn- fibers twisted together.
16-3 KNOTTING AND HITCHING The use of rope as hoisting medium is considered as part of bui.lding construction which could not be avoided in lifting ma. terials or structural members specially in mu lti-storey building construction. Definitely~ only few if not all of the working crews know the art of tying, knotting and hitching of rope which everyone should learn. Some accidents that happened in building construction are caused by fallen objects due to faulty and Inadequate l;
{2) Whipping the rope end
'
1
Fig.-16·1 16-2
298
Fig. 16 • 3 bight
loop or turn
round turn .
Fig. 16-4 Cat's Paw
Fig. 16-5 Running Bowline
299
Fig. 16·6 Blackw,fl Hitch
. . Fig. 1&-7 Anchor bend or Fisherman's bend Fig. 16-8 Combined Timber and Half hitrh
Fig. 16-9 Taut line or Rolling hitch 300
Fig. lG.lO Sheepshank-used for shortening a rope
Fig 16-11 Slip knot
Fit. 16-12 301
Fig. 16-13
Bowline Knot
II
Fig. 16-14
Eight Knot
HAlf WITCH
Till• i• temporory OM oot
ver ~· ••e111e
Figure 16-15 302.
to•••~>lnQ
Half Hitch
---
Wrong Way
Ri Qhl W a y -
TWO HALl" H I TCH
Fig. 16-16 Two Half Hitch
Fig. 16-17 Bowl ine on a Bight
Fig. 16· 18 Scaffold Hitch 303
16 - 4
PULLEYS
Pulley is a mechanical device used for lifting heavy weights. The combination of ropes and pulleys to gain mechanical advantage in lifting a load is called block and tackle.
Block and Tackle
Worm Gear Hoist
Chain Block
Fig. 304
1~19
Differential Hoist
Snatch Blocks
I ron Sheave Blocks
Wooden Blocks
Fig. 16-20
305
16 • 5 CIRCULAR SAW Circular Saw is a steel disc provided with teeth designed to revolve on a shaft at a high rate of speed. The speed of the saw is measured either by the number of revolution per minute (rpm) or the number of meter traveled by the run per minute. Light portable mills run approximately 450 to 650 rpm. The high speed steam fed mills run about 600 to 900 rpm, and the I . small circular table saws by hand fed runs about 2000 to 3000 rpm. In mills wher& power is limited~ it is not advisable to have more than one tooth ~or every 25 mm of the saw diameter. The fewer the teeth in the saw the less power it requires to rotate. However. small saws requires more teeth to equalize the strain. For hardwood and soaked lumber, it is more effective to increase the speed rather than increase the number of teeth. More teeth means finer dust which could easily packs between the saw and the wood.
Fig. 1S.21
16- 1
REVOLUTION OF CIRCULAR SAWS· (For tangential or rim speed of 3,000 meter per minute}
Diameter em
20 25 30 40 50
60 70 80 90
Revolutions per minute
4600 3920 3260 2450. 1960 1630 1400 1225 1080
Diameter
em 100 110 120 130 140 150
160 170 180
Revolutions per minute
980 890 815
750 700 640 600 560 530
Kinds of Saw and their Uses- The circular saw is used to cut lumber to length and width as required in the construction. It also cut rabbets grooves, dadoes and tenons. The saw cuts under the principle of continuous set cutting of wedges. The different kinds of saw are:
1. Crosscut Saw - has greater number of teeth designed for cutting across the grain. It will heat fast if used for ripping because of the greater number of teeth in contact with the wood. Overheating the teeth of the saw blade causes warping and wabbling run making an inaccurate cut. 2. Ripsaw - Is designed to cut along the direction of the grain. 3. Combination Rip and Crosscut Blade- is a combination of crosscut tooth and a rip tooth to cut wood across the grain, diagonal to the grain or with the grain. It is consi· dered as a fast cutting saw but produces a very rough cut. 4. Carbide Tipped Blades- Are made for both cross-cutting and ripping. This type of saws are used on hard board, laminates and .other materials where a regular saw would become dull quickly. 307
5. Safe Edge Blade - is a control led-cut saw blade with a fewer number of teeth and requ ires less power to run. It is considerably quite in operation. 6. Moulding Head and Cutters - has a replaceable blade of various type of moulding heads that could be assembled or disassembled quickly. 7. Dado Blade Set -· is used to cut grooves (dado and rabbets from 3 mm to 25 mm width regardless of the grain direc· tions.
Form of Teeth -r- The success and failure of the circular saw depends upon th e hook or pitth, depth, size and shape of the gul· lets. .Too little hook causes tearing and scraping instead of cutting. The teeth becomes dull quickly and the severe strain in the gullets stretches the rim and requires more power to force the saw through the lumber. On the otherhand, too much hook weakens the tooth and make it liable to break or dodge. A satisfactory performance of a hook could be attained if the base of the tooth are rounded-off into a round gullet providing enough space to carry out sawdust leaving a strong base for the tooth.
TIIO IIOtt Ia Wiele arul •tr0119
w.n
IOIIIIded
to loovo •-lot~• 911llot .Rownded •ullete ••olll pocllll'lt. ol Mwd•et .
Strolgllt teeth cut l'lord ond dull ~ulckly, Sharp OIHJies in the illroot c au•ts crocllleta. Deep oftd 1\0trow gvlleh cau•• w•l1oino and cllo'HII\O ottow
Figure 16·22
308
Selection of Blade - Circular saws are selected according to the type and number of teeth, the gauge thickness of the blade, the arbor hole diameter and the grade of the steel from which they are manufactured. · It should be remembered that the more teeth in contact with the wood the more power is required to rotate the saw to its specified round per minute. When the blade of the saw is exposed more on the surface of the lumber being cut, the greater the danger to the operator. The safety rule of 3 mm to 6 mm projection above the board should be strictly observed when the saw is not covered by a guard.
TABLE Crosscut saws
16- 2
BLADES FOR CIRCULAR SAW
Ripsaws
Combination Rip & Crosscut saws
Easy Cut Saws Carbide Tip
Diameter No. of No. of No. of No. of em Gauge Teeth Gauge Teeth Gauge Teeth Gauge Teeth
15 17 20
100 110 100 100 100
18 18 18 16 16
36 36 36 .36 36
18 18 18 16 16
44 44 44 44 44
14 14
8
14
25
18 18 18 16 16
8 8 8
30 35 40 45 50
14 14 14 13 13
10.0 100 100 100 80
14 14 14 13 13
36 36 36 ·36 36
14 14 13 12
44 44
13
44
12
55
12 11
70 70 70 70 70
12
60 65 70 75
11
36 36
10
36
22
10 10 10
14 13 12
8
12 12 12
44
309
16 - 6 RADIAL ARM SAW Radial arm saw is a power driven rotary cutting tool. It is a refinement of the overhead swing saw. The saw arbor and the motor unit are attached to a pivoting yoke riding on a track with a radial arm adjustabl e for height and radius angle.
The .circular cutter revolves at a speed between 3500 to 3600 rpm used to cut lumber to length and. width. It is also used fo~ making grooves, dadoes and tenons.
•.t.DIA~ ..... lAW
Figure 16-2 3 TABLE 16-3 Blade Size em
310
RADIAL ARM SAW CUTS Depth of Cut em
Length of Crosscut
em
20
5
29
22
6
30 -38
25
7.5
30 - 40
30
8--9
36
35
45 - 60
40
12 10-12
48- 78
45
15
Depends on
50
17
lenth of arm
16-7
PORTABLE ELECTRIC SAW
Portable electric saw is also a power driven rotary cutting tool provided with toothed circular blade. The blade revolves at an arbor speed between 3200 and 4500 rmp. depending upon the machine. The portable electric saw is a handy power tools for construe· tion work. It is very effective tool in fhe construction of framEr work, roof framing job particularly on angular cuts for stair jacks and truss members. The saws are classified according to blade size which could be available in 15 em, 18 em, 20 em and 22 em mo· dels. The Capacity of the saw to cut are as follows: a. b. c. d.
A 15 em saw will cut to a depth of 47 mm An 18 em saw will cut to a depth of 63 mm A 20 em saw will cut to a depth of 70 mm A 22 em will cut to a depth of 82 mm
PORTABLE ll.ECTRIC SAW
16-8 PORTABLE ELECTRIC DRILL Portable electric drill is a motorized rotary driving tool. It operates from a small high-speed electric motor with gear.reduction driving devices. Usually, electric drills are designed with a pistol shaped housing for holding drill shanks up to a diameter of 10 mm with handle. for heavy duty work up to .12 mm diameter. 31l
Electric drill is used to drive all types of rotary cutting tools in the construction work. Special attachments could be used as driving unit for sanding, polishing and grinding as well as for cir· cular and jigsaws. Some drills have a. variable speed unit attached to the trigger switch to give a speed from 0 to 2250 rpm.
Figure 16- 25 TABLE 16 ...- 4
ELECTRIC DRILL SIZ!=:S AND SPLEDS
6 .mm (1/4) 8 mm 10 mm 12 mm 16 mm 19 mm 25 mm
16-9
-Speeds to 2000- 2450- 5000 rpm. (5/16)- Speeds to·lOOO rpm. (3/8")- Speeds to 750- 1000 rpm. (liz") -Speeds to 450- 750 rpm. (5/8")- Speeds to 300 rpm: (3/4") -Speeds to 250 rpm. (1") -·speeds to 200 rpm.
DRILL PRESS
Drill Press is also a power driven rotary driving tool for driving drills, bits, plug cutters, and many auxiliary attachments such as mortise chisels, grinding wheels, and shaper cutters. The speed of the drill press vary from 300 to 700 rpm. The speed is controlled by shifting the drive belt on a set of con.e pulleys which operates on the principle of the wheel and axle. With the various attachments it could be utilized as a sander, planer; shaper, router and mortiser. The table sizes are : 25 x 25 em: 25 x 35·cm; and 28 x 40 ern. 3l2
Figure 16 -
16- 10
2G
PORTABLE ELECTRIC SABER SAW
The portable electric saber saw is sometimes called bayonet saw, classified as power driven reciprocating cutting tool. It is driven by a h igh-speed electric· motor and has a mechanism for changing rotary to reciprocating mot ion. This is a heavy duty type all purpose saw design for construction work. It holds a saber blade from 8 em to 30 em length and cuts flush to a vertical or horizontal surface. Originally, saber saw ·was designed only to cut wood, but because of its performance versatility with variable speed adjustments are now being used on metal, plastic lam inates and composition materials. The saw could start from the center of the materials withou t the necessity of advancing a pilot hole drilled on it.
PORTABLE
ELEC TRIC 'SA81!:~ SAW
Figure 16 - ·27 313
16-11
BAND SAW
Band saw is a power-driven endless toothed band cutting tools. Band saw is more extensively used and preferred than the circular saw for heavy duty work. The preference of band saw was brought about by the saving in wood due to the lesser amount of cut away in the sawing operation. Band saw is described as a thin strip of tempered flexible steel belt with rip teeth filed on one edge and run around two pulleys at a speed from 900 to 1500 meters per minute or 600 .to 1200 wheel round per minute (rpm). the saw cuts under the principle of continuous set of cutting wedges. The saw is used to cut curves, ripp ing, and cross cutting available in the following wheel si~es: 30, 35, 40, 45, 60, 75, 90 and 100 centimeters diameter. The blade widths ranges from 3mm, 5mm, 6mm, lOmm, 12mm, 16mm and 20mm. The motor is usually of liz to 3 horsepower rated at 1720 rpm 60 cycle either single or three phase electrical power supply.
Y'HROAT PUll TAIL£
BAND SAW
Figure 16 -'28
3l4
How to determine the length of the Band Saw blade:. 1. Measure the center distance between the two wheels. 2. Use Formula (R 1 x 3.1416) + (R:l· x 3.1416-t- (2+ C) = Length ·
Figure 16- 29 The two types of Band Saw teeth are:
1. Regular standard rip shaped tooth 2. Raker tooth
Figure 16-30 TABLE 16-5
Width in mm 5 6 10 13
19 25
SKIP TOOTH BLADE SIZE
23 23 23 23
Teeth per em 1.5 1.5 to 2.5 1 to 1.5 1 to 1.5
21 20
1 1 to 1.5
Gauge
315
TABLE 16-6
REGULAR RIP TOOTH BLADE SIZE
Width mm
Gauge
3
25
5
21 22 25
2.5 1 to 2 2-2.5 2-2.5
6
21 22 25
1-2 1.5-2.5 2 -·· 2.5
8
21
1 -- 1.5
20 21 22 25
1 1-2 1.5-2 2-2.5
13
20 22 25
l-1.5 1.5-2 2-2.5
19
19 25 19-22
1.5-2 1-2
10
25 TABLE 16- 7
5 6 10 13
16 316
1
SAW BLADE WIDTH FOR CUTTING CURVES
Width of Saw Blade mm 3
No. of Teeth per em.
Minimum Diameter of Circle mm
25 38 50 63 76 89
16- 12
SINGLE SURFACE PLANER
Single Surface Planer rs a power driven rotating edge-cutting tool. The full-width knives are set equidistant along the circumference of the cutter head which rotates at a speed 3600 to 7200 rpm. The knife cuts under the principle of a continuous set of cutting wedges.
Figure 16- 31
16-:- 13
PORTABLE SANDERS
Portable sander is a power driven abrading tool classified into three types: · 1. On the Belt Sander, a coated abrasive belt is run over a · pad guided by an idler and driving drum 2. On the disk sander - a coated abrasive disk rotates on a motor spindle. 3. On Finish Sanders - a coated abrasive strip fitted over pressure pad is powered in an orbital or inl ine oscillating motion.
a
Figure 16- 32 317
Disk Sander - is on rough sanding for fast removal of the stock. Finish Sander= has two different sanding motions:
a. Orbital motion sander used to finish sanding with fast circular pattern. b. lnline sander's cutting action is back and forth in a straight line .which is ideal for the final sanding of wood surfaces, leaving no sanding marks on the surface.
16-14
PORTABLE HAND ROUTER
Portable hand router is a power driven rotary shaping tool that revolves at a spindle speed of 5,000 to 27,000 rpm. shaping under the principle of a continuous set of cutting wedges. Hand Router is used to cut moldings. rout cut grains for inlay and cut dovetails.
a
r:7
llnft4in!l
• 3.18
Figure 16- 3 7 . Shapes and uses of power router bits.
16-15
WOOD LATHE
Wood lathe is classified as powered rotary driving tool. The lathe is used to rotate the materials for shaping, sanding or polishing. It is also used as a holding jig for flut ing, reading, and drilling holes. · the usual capacity of the lathe are:
1. 2. 3, 4.
22 em swing- 75 ern bet~n centers. em swing- 90 em between centters 30 em swing - 90 em between centers 35 em swing 90 em between centers.
27
The speed of the belt driven lathe is maintained by step or pulleys which operate on the principle of the wheel and axle. When the driving pulley is smaller than the driven pulley the speed is reduced; Likewise, when the driven pulley is smaller than the driving pulley, the speed is increased. The speed of the lathe maybe regulated between 300 to 3600 rpm. ~one
Figure 16- 34
319
1. Gouge = Is used in roughing out cylinders and in turning concave surfaces on spindles. The blade is concave-convex in cross section with a rounded bevelled cutting edge. The common size are: 10 mm; 12mm and 20 mm. 2. Skew Chisel = Is a flat turning chisel used in smoothing cylinders rounding edges and in making V and shoulder cuts. It can be used for shearing or scraping wood. The common sizes of skew chisels are: 6 mm, 12 mm and 25 mm. 3. The Roundnose = Is a flat scraping chisel used in roughing . and shaping concave surfaces. The end is rounded with a single bevel of about JOO. The common sizes are 3mm, 6mm, 12mm, and 25 mm. 4. Squarenose == Is a flat scraping chisel used to make flat, straight cuts. It appears like a standard wood chisel in shape but has a thicker and longer blade. The end is square and has a single
bevel. 5. Diamond Point = Is a flat scrap ing chisel used to make V cuts. The point cutting edges is beveled at 300. The common sizes are: 12mm 6. Parting To~ "' Is a scrapln9 chisel used to make deep, narrow cuts and a deep cuts for sizl"9 when shaping profiles. The common sizes are 3mm and 5mm.
S c ew
Squvreoose
Oiamooa Patn l
TURNING CHtSE LS
Figure 16 - 35 ·320
Roun dllasP.
Pari ing
16- 16
TRUCK MOUNTED CRANE
A machine used for lifting or lowering a load and moving it horizontally in which the hoisting mechan ism is an integral part of the machine: classified by mounting by boom configuration and by lifting capacity.
Fig. 1&- 36
16- 17
TOWER CRANE:
A type of crane consisting of a fixed vertical mast wh ich is topped by a rotating boom, equiped with a winch for hoisting and lowering loads and placing them at any location within the diameter of the boom.
t~rcrone
Figure 16·37 .321
322
APPENDICES
323
Appendix
1
Mllltipla•..d ~plu 1 000 000 000 000 - to•a 1 00() 000 000 - 109
r ooo ooo ... to• 1 000 = JOl
= 101 10 = 10
100
0.1 • to-• 0.01 ... 10~ 1 0.001- 10-l o.ooo 001 = to-•9 o.ooo ooo 001 = ro0.000 000000 001 • to-u 0.000 000 000 000 001 • 10-u
o.ooo ooo ooo ooo ooo 001 - to-''
~
s,mbols
tera
T
gig a mega kilo hKtO deka deci centi milli micro nano pico femto atto
G
M* k* h
da d c* m* lA*
n p f
a
• Mosc commonly used
Common EqulvaJents and Conversions Approximal~ commcm ~quivalmts
J inch I foot
I yard 1 mile 1 square inch 1 square foot 1 square yard I acre I cubic inch I cubic foot 1 cubic yard 1quart I gallon
1 0\ince(avdp) 1 pound (avdp) t honepower 1 millimeter 1 mete.1 meter I kilometer 1 sq centimeter 1 sq meter
= 25 millimeters = 0.3meter = 0.9meter
· • 1.6 kilometers =6;5 sq centimeters .;, 0.09 sq meter == 0 .8 sq meter ::: 0.4 hectaret = 16 cu centimeters = 0.03 cubic meter = 0.8 cubic meter = 1 Utert = 0.004 cubic meter a 28grams • 0.45 kHqvam =0..75 kilowatt = 0.04inch .. 3.3feet
"'l.t yard& ... 0.6mile =0.165Q inch
= II sq feet
325
1 sq meter ·.1 hectaret 1 cu centimeter
1cu meter 1 cu meter
·1tttert 1 cu meter 1gram 1 kilosram I kilowatt
"' 1.2 sq yards ., 2.5acres =0.06 cu inch = 3Scufeet = 1.3 cu yards = 1 quart = 250 gallons = 0.035 ounces (avdp) = 2.2 pounds(avdp) = 1.3 horsepower
t common term not used in Sl
Conversions accurate to p4rts per million
inches x 25.4* feet x 0.3048* yards x 0.9144* miles x 1.609 34 square inches x 6.4516* square fl!et x 0.092 903 0 square yards x 0.836127 acres x 0.404' 686 cubic inches x 16.3871 cubicfeet x 0.028 316 8 cubic yards x 0.764 555 quarts {liquid) x 0.946 353 gallons x 0.003 785 41 . ounces(avdp) x 28.3495 pounds (avdp) x 0.453 592 horsepower x 0.745 700 mmimeters )( 0.039 370 1 meters x 3.280 84 meters x 1.093 61 kilometers x 0.621 371 sq centimeters x 0.155 000 sq meters x 10.7639 sq meters x. 1.195 99 hectares x 2.471 05 cu centimeters x 0.061 023 7 cu meters x 35.3147 cu meters x 1.307 95 liters x 1J557 cu meters·'x 264.172 grams x 0.03.5 274 0 kilograms x 2.204 62 kilowatts x 1.341 02 • exact
.326
= millimeters =meters =meters = kilometers =sq centimeters =sqmeters = sq meters ==hectares = cu centimt!ters =.cumeter• = cumeten =liters == cumeters = grams =kilograms = kilowa.tts =inches =feet ""yards =miles = sqinches =sqft = sqyards =sqacres = cuinches = cuft = cuyards = quarts (liquid) =gallons = ounces (avdp) = pounds(avdp) = horsepower
App.ndix 2 -
Typlcol ............
acre • • . • • • • • . . • • . • • . • no authorized abbreviation
atmc:.pMns . . . . . . . . . . . . . . . . . . . . . . . . . • . . • . . atm British theimaJ uniu ....................... Btu British thermal uniu per hour . . . . . . . . . . . . . . Btuh cubic feet . . • • • . • • . • . • • . . . . . . . . . . . . . . . . • . . • . . . ft3 cubic feet per minute • . . • . . . • . . • • . . . • . • • • ft3/min cubic feet per second ................ .. 1 • • • • ft3/s cubic inches • . . • . • • • . • . . . . • • . • . . • • • • . • • . . . • . in' cilbic mete-rs • . . • • . • . • . . . . . . . . . • . • . . • • • • . . • . • m, cubic millimeters ............... ; . • . • •.. • . . • mmJ cubic yards •........•.. ; • ·. • • . • . . . . . . . . . . • . . . yd' feet . • . . • . . • . . • • . • • . . . . • . . . . . . . • • . . . . • . . . • • . . • ft feet of water . . . . . . . . . . . • • . • . . • . . . . . . . • • . • ft H20 feet per second . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ftls foot·pounds of force • . . . • . . . .. . • . . . . . • . . . • . lbflft pitons ..................................... gal pllons per hour . • • . • . . • . • • . . • . . . . . . . . . • • . . gallb pllons per minute . • . • . . • . . . . • ... . . . . . . . . gal/min p-ams •••.•••.••..••.••.•..•..••••.••.•••.••.•• g
grams per square meter ............... ~ • • . • . rJm2 hecta:J.es ••. . •• . •• . •• . •. . • . . . . . . . . . . . . •• . . . . • ha horsep<)w~r ....................·. . • . . . • . • . . . • • • hp inches .....•••.• ,. .•.••••..............•.•••.• in inches of mercury . . . . . . . . . • . . . . . . . • . . . . .. • in Hg inches of water .. • .. .. . . .. .. .. . .. .. • .. .. . in H20 joules· .............................. • •...••....••. J
kiloc:alories . . . . . . .. . . • • . • . . . . . . . . . . . . . . . . • • . kcal kilogra. ms . . . . . . . . . . . . . . . . . .·. . . . . . . . . . . . . . . . . kg kilograms per cubic meter . . . . • . . . . . . . . • . . • ksfm3 kilograms per second •..•...• ; ......•• ; . • . . • kgls kilograms per square meter • • . . . . • . . . . . . . . kgfmt kilojoules • . • . • • . • • . . . . . . . . . . . . . . . . . . . ,. . . . . • . kJ kilojoules per cubic meter . . . • . . . . . • • . • • . . • k.Jim' kilojoules per kilogram .•..•..•....•.•.. ~ . . kJ/kg kilometeri ..•.••..•••••.•.•• ·. . • • . . . . . • . . . . . . km kilometers J)ef hour .••.•.•••.•...••.· • • .. . . . . k~ kilonewtons ...• ·............... ; • • . . • . . . . . . . kN kiloa>ascals •..•.·.•. ·..•. ; .... ~ .•.............. · kPa '327
kilowatts . ... .............. .. .... ............ l(W kilowatt·hours ........ ~ ........... ... ..... kWh . liten ... .. ................... ! ..... .... ..... .. .·. • . I liters per $econd . . . . . . . . . . . . . . . . . . . . . . . . . . . . . lis liters per minute ........... : . . . . . . . . . . . . . . I/min megajoules ............................... .. ~ MJ mepnewtons ......................... : . . . . MN ~egapascals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MPa meters ............. .. ........ . .............. m meters per second . . . . . . . . . . . . . . . . . . . . . . . . . . mls miles . . ..... . ....... . .. no abbreviation in metric miles per hour . . . . . . . . . . . . . . . . . . . . . . . . . . . milelh millimeters ..... ... ...... .. ..... ... .. ·...... mm millimeters of mercury .................. mm Hg newtons .......................... . .......... N ounces .... .... .... .... .... .... .... ..... ... .. oz ounces per square foot ... ... .. , . . . . . . . . . . . . oz/ft 1 pounds ...... .. ............ . ............... .. lb pounds of force ...... .. . . .... ... . .... ... .... , lbf pounds of force per square foot •.. ... ·. . . . . . . lbflfta pounds per.cubic foot ..... :. . . . . . . . . . . . . . . . JblftJ pounds per second . . . . . . . . . . . . . . . . . . . . . . . . . . lbls square feet .... . ................. : . . . . . . . . . . . ft1 square inches ......................... ·. . . . . . in2 square kilometers ......................... . km1 square mete.rs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . m2 square miles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . miJe2 square millimeters . . . . . . . . . . • . . . . . . . . . . . . . mm2 watts ............................... ......... W watts per square meter . . . . . . . . . . . . . . . . . . . . Wlm' yards .. .... ................................. yd
3.28
Appendix 3 -
UMfwl coav..-. foctort:
AlphoMtin4
by to~~ Multiply 1cres . . . . . . . . • . . . . . . . . . . . • . . .. 0.<4047 ....... hectares lcres ..........•............ : . 4,047 . . . . . . . . square meters 1tmospheres .................. 33.93 ........ feet of water ltmospheres ................... 29.92 ........ inches of men:ury ltmospheres ...•...•.......... 760.0 ........ millimetersofmercury ltmospheres . . . . . . . . . . . . . . . . . . 1.058 . . . . . . . . tons per square foot ~ritish thermal un~ts .......... 1.055 .•.... .:.joules [Jritish thermal units •......... 0.2520 .....•. kilocalories 1Jritish thermal units ....•..... 1.055 .•.••. ,; . kilojoules iJritish thermal units per hour .. 0;2929 ..•... ·.watts [Jritish thermal units per pound . 2.326 ....... 1• kilojoules per kilogram :ubic feet ..................... 0.02832 ...... cubic meters :ubic feet .............. ~ ...... 7.481 . .. . . . . gallons :ubic feet ..................... 28.32 . • .. . .. . liters :ubic feet .... , ................ 29.92 ........ quarts :ubic feet per minute .......... 0.4719 ....... liters per second :ubic feet per second .......... 0.02832 . . . . . . cubic meters per second :ubic inches ................... 16.39 ........ cubic centimeters :ubic inches ...............•... 16,387 ....... cubic millimeters :ubic meters .................. 35.32 ........ cubic feet :ubic meters .................. 1.308 • • .. • .. . cubic yards :ubic millimeters .............. 0.00006102 or (6.102 x 10-~ . cubic inches :ubic yards ................... 0.7646 ....... cubic meters eet ...........•.....•..•.•.... 0.3048 ....... meters eet ....•...•.............. ·..... 304.8 ........ millimeters eet per second ................ 0.3048 .•....• meters per second ~t·pounds of force ............ 1.356 ...•.... joules oot-pounds of force per second . 1.356 ...•.... watts :allons (liquid) ........•....... 0.003785 ..... cubic meters :allons ....................... 3.785 ........ liters :allons per hour ............... 0.001052 ..... liters per second :allons per rninute ............. 0.002228 ..... cubic feet per second :allons per minute ............. 0.06308 ....•. liters per second :rams ........................ 0.03527 ..... · . ounces (avoirdupois) ;rams per square meter ........ 0.003l78 ..... ounces per square foot ;rams per square meter ........ 0.02949 ...... ounces per square yard 1ectares ...................... 2.471 .. ~ ..... acres torsepower ...... ~ ............ 0.7460 ....... kilowatts ~29
Multiply
by
to gt!t
horsepower . . . . . . . . . . . . . . 746 ....... watts inches ............. . ...... 25.4 ...... millimeters inches of mercury . ........ 0.03342 . : . ~tmospheres inches of mercury . . . . . . . . . 1.133 ..... feet of water inches or mercury . . . . . . . . 345.3 .. ... kilograms per square meter inches of mercury (60° F) ... 3,377 . . . . newtons per square meter inches of mercury ......... 0.4912 .•. . pounda per square inch inches of water ............ 0.002458 .. atmospheres inches of water . . . . . . . . . . . 0.07355 ... inches of mercury inches of water ........... . 25.40 . . ... kilograms per square meter inches of water . . . . . . . . . . . . 0.03613 . . . pounda per square inch in<:hes of water (60° F) .... .. 248.8 ..... newtons per square meter joules ..................... 0.7376 .... foot-pounds offorce kilocalories · ............... 3.968 ..... British thermal units kilocalories .. . .. . .. . .. . .. . 4.190 ..... joules kilograms ................. 2.205 ..... pounds kilograms per cubic meter .. 0.06243 .. ·. pounds per cubic foot kilograms per cubic meter .. 1.686 ..... pounds per cubic yard lcilograms per second ...... 2'.205 ..... pounds per second kilograms per square meter . 0.00009678 . atmospheres kilograms per square meter . 0.003281 . . feet of water kilograms per square meter . 0.002896 . inches of mercury kilograms per square meter. . 0.2048 .... pounds per square foot kilograms per square meter . 0.001422 .. pounds per square inch kilojoules ................. 0 .9478 .. .. British thermal units kilojoules per cubic meter 0.02684 British thermal units per cubic foot kilojoules per kilogram ... · 0 .4299 .... British thermal units per pound kilometers ................ 0 .6214 .... miles kilometers per hour ..... .. · 0.62 t 4 · · ·. miles per hour kilonewtons . . . . . . . . . . . . . · 0.10036 · ·. tons of force kilonewtons . . . . . . . . . . . . . 224.8 · · · . pounds of force kilopascats . . . . . . . . . . . . . . . 20.89 ····.pounds offorce per Square foot
330
kilowatts .. .. ............. 1.341 ..... ·horsepower kilowatt-hours .... . ....... 3.6 . . .... . . megajoules liters · ...... ... . .. . .. ...... 0.03532 ... cubic feet liters ..... ....... . . . .. .... 61.02 ..... cubic inches liters ............. ...... .. 0.2642 .... gallons liters . .. .. . ........... . ... 2.113 ..... pints liters .. .... ............... 1.057 ..... quarts liters per minute .......... O.OOOS886 . cubic feet per second liters per second ..... . . ... . 2.119 .. . .. cubicfeet per minute liters per second ...... ..... 951 .0 . .. .. gallons per ho ur liters per second ....... .... 15.85 ..... gallons per minute megajoules .. . ............ 0 .2778 .... kilowatt-ho urs meganewtons ............. 100.36 .... tons offorce mega pascals .............. J 45.04 . . .. . pounds offorce per square inch megapascais ... · . · · · · · · · · . 9 .324 . . . . tons of force per square foot megapascals .... · ... · · · · · . 0.06475 ... tons of force per square inch meters . . .................. 3.281 ..... feel meters .................... 1.094 ... . . ya rds meters per se'cond . . . . . . . . 2 .23 7 miles per hour miles . . . . . . . . . . . . . . . . . . . . 1 .609 . . . kilometers . kilometers pe.r hour miles per hour . ·. . . . . . . . . . · 1:609 miles per hour . . . . . . . . . . . · 0.4470 .... meters per second miJiiliters . ............... 0.06102 ... cubic inches milliliters . . . . . . . . . . . . . . . . 0.03520 .. . fiuid ounces millimeters .... ....... . ... 0.0394 ... . inches ·millimeters of mercury ... 133.3 ..... newtons per square meter million gallons.per day .. .. 0 .005262 .. cubic meters per second newtons . . . . . . . . . . . . . . . . . 0.2248 .... pounds of force ounces (avoirdupois) . . . . . . 28.35 ..... grams ounces (fluid) . . . . . . . . . . . . . 28.41 ..... milliliters oun~s per square foot . . . . 305. J5 .... grams per square meter ou~s per square ya rd .... 33.91 ... . grams per square meter pounds . ................. 0 .4535 .... kilograms pounds of force . . . . . . . . . . 4.448 . .... newtons pounds offeree per square . 4 7.88 ..... pascals foot
331
pounds of fo rce per square indt .. 6.895 . . . . . kilograms per second pounds per cubic foot ... .. .. ... 16.02 .. . .. kilogJ"ams per square meter pounds per cubic yard ... . .. .. . 0.5933 . . .. . k.ilopascals pounds per second .. ·. . . . . . . . . . 0.4535 .. :... kilograms per cubic meter pounds per square foot ......... 4.882 ...... kilogr ams per cubic meter quarts ... .. .. ... .. .... . .... .... 0.0009463 . . . cubic meters squa~ feet ............ . ....... 0.0929 . . . .. square meters square inches .. ... .. .. .... . ... 645 .2 . ... . . square millimeters square kilometers ............. 0 .3861 ..... square miles square meters .. ... . .... ... •. . . 10.76 . ... .. square feet square meters ................. 1.196 ...... ~quare yards square miles . . . . .. ... .. .. ... .. 2.590 . ... .. square kilometers square millimeters ............ 0.00155 .. . . square inches square yards . .. .•........... .. 0.8361 ... .. square meters tons of force . . ... . ............. 9.964 ...... kilonewtons tons of force per square foot •. .. 107.25 ... .. kilopascals tons of force square inch .... IS .44 ...... megapascals torr (millimeters of mercury at 0° C) ..... . ....... 133.3 ..... . newtons per square meter watts . . .... .. ... .. .... .. .. . ... 3.412 ...... British thermal unit! per hour watts . . ... •... .. . .. ... .. · .. .. 0 .7376 . . . . . foot-pounds of fcM-ce per second yards . ... .. ... .. .. ... .. .. ... .. 0.3170 . .. . . . British thermal units per square foot watts per square meter ... . · · .. 0.9144 ... ; . . meters
per
332
............. Applicatloa . . . . UfUIUC Qll 'nE FIIILIPPllii!S IIIIIlSTIY Qll PUILIC 1IOUS
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Appendix IIII'Vt-1.1COF THf fi'H!I.IrPtNU
'Q1ill''flll0. ??-QQ1-S
PEPA RTMENT OF PU8LIC WOAKI. TAANIPORTATIOOO ANP -IJ!IIICATIO. . OFfiCI OF THE EIUILDIIIG O"ICIAL
0 ltTfUC'TIC11"V/IIIUNt(:lfJALIT'I' AH'I.Ic.\T10H NO.
'lk..tT NO.
AA I~ coo• -----·-
I I II I II
II I II I
SANITAI'IY"'LIMBINO PEI'IMIT
0ATI.I$SUID
OATIOF' """LICATI()N
NA»l OF OWNff\fAPPI.ICANT
U.h NNAI , , tftiT NAMI, M,l ,
TAX: ACCT. NO.
ACORn'
NO .• .sTAttf, t.AfiA'tOAY, CI T'f/WUWICI'AUTY
TEl EP+40~l ..0 .
HO,.IT"!IT. Ml'tANQAY, C:tl'rfltN'HlCJ:ftM.ITY
C.OCATIOH OF JHITALLATJON
Q AOOtTION Of'
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0 SUfi..Aet OltAtHACM 08,.,.QT(MAL. 0 ,... n" cou•u
TOTAL AfltA Oft M.IU,.Dt~G/8U801V11tON
...
TOTAL CDn Of' t:NJTAI.t..A'ftOfril P: rRSI'AA'O &Y
• IXNCTID OATL OFCOIIIPUTJON
rt:AMIT II Hffii!IY (JfiiANl'to TO lilftTAU. TWI IANI TAf\V/P'L.UM~..G F 1Jt1\lflll lNUWI.ftATlO MMltN SUIJECT TO 'n4E P-OU.OMNG. COND4·
,.,...
t . ~T 1ltE ,.,...,..-0 I.MITAU,.AllON I HAU. 1'1 JN ~ wtTM ~0 "-AMM ' K.ID W UJH THiS O''lCI o\HC ' PI ~OA ..ITY '"TH TH.I IU.nOHAL IUILCtt4G C:OOE. :l. T)'tAT A OULY LJCIJIIIED IAHtTAI'tY IINCI~Iil ftiMAI'Tifl P\.UM.I.fl
If
f.N~AGIO
TO UNOIRTME TNf
JNITAU.J~nott/COHITRUC1'10,.
$, THAT A tERTifiCl.ATI Of t:Oall"t.E'nON OVLV IIQNID JY A.tAN ITAAY
t:NGINf€f'IMA*Ttf' 'WMII.A ftljl CHAAGl OF INITALLATIO" '"AU. •• I UIMmiO frfOT lATE" 1'l4AH UYEN (7) DAVI AFTIR COW LtTION 0''tf1E UWfALloAnOH. 4. THAT A C:I.-T~P.ICATI OP PIMA(. I,_IH:C'TtOH ANO A Qll'tli111C.ATI Of OOCUf'MCY II I~!D , . JOft TO TKI AeTUAL OQCUP~ftCY' Of:
' DATI
r tttautL.DttrfO
HOTI•
THill Pe:AMIT ..AY .. CAN(.ILUO Oft IIII VOKtO,Ufi!WAffT 10 IICJtOfrfl ac»a _. 0 , HIE "'fiiATIOft'IA\. MIIL04NGCQ011""
315
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AOOitEst f'. T . fii , NO. t.ION4TI.PIIIS
336
,-----------------------~
I OATE I.stV[O I 111''-ACI 'I
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Fe~~eia1
Appendix 6 ..., rou No. 7'1-oot·l
P...ut Appllcellea Pe,.
1 1 - G P TIC .....__.
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Appendix ..7 -
Appllc.tt. for Electrial Penait Fo"" Rf,\JB~~C 0 ,: H4€ PHIUPPINES
O""'TC FOAM.NO. n-MFW
Df i'AIITMENT OF PUBLIC WORK&. TAANSPORTATION ANO COMMUNICATIONS OFf iCE OF THe BUILDING OfFICIAL D IST.. H:fiCITV/NUNIC.,Al tTY
1:1 II
II
AflilllA COOt -
I I
-
-
PERNU'T NO .
--
ElECTRICAl. PERMIT
DATI Of APPLIC ATION
II I I
II
AP!"UCATION FOR
I I
OAT[ tSSUEO
...
.0)( 1 CTO &E A~COMPliSHI08Y PA.OFfSSION• L E'-l.tTAICAL INOtNitPIJ~AilER ElECTfUCJAN IN PP:!flrtTt TAX ACCT. rtn. NJ\Ml Of OWJ
AOOIIE$$ \.OCAl,OHOF INSTAU,ATION
NO .• STREET. BARANGA Y, CIT Y/MU NIC.,AU TY
a a
I')OPI OF WORK
a
0
Tt.U~EHO .
NEW INSTAL~TION AMNVAL aNIPECTION
0
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a
OTHERS tSPECIFVl OF OF
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AGRICVL TVAAL S'TfiiEET FVRNlTUAE.I..ANOSCA" NO SIGNIOARPS O'TIItRS ISI'ECIFVI
__ .....__
DATE OF PROI'OifO STAAT Of- CONSTRUCTION
D cONv. OVTun Ow/4.Ti fii HEA-rv. 0 OIOTOAS
- "·" -- -
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EX'ECTEO OATf OF COMP\.ITJO"
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-
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IOJC l srEASC* WttO JtG..I O AHO liAt.tO PLAfrtS • PICI,ICA TJOM.
ll.KTIIICAL IJ«luret:IN _ . , . ILI!eTAICIAN
""CAIO. NO.
.
rAfNTNAME
AOOI'IEIIS
, .T.R.NO.
!LECfJIIICAL t:HOIHEI RI MAITift fLICTRfCfAN f'IUfll t HAM'e
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·'
AOOAESS
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1 DATE ISSUEO
1'\.ACE IS5liED ITA~.
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TAX ACCT.N(I,
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I
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8 ffO 8£ ACCOMPt.ISWED ev 1'Hl IUit.Dt~() OfFtCtAU
&CfiOIII'fA.tN PEIAMIT 1$ MEfll U Y GAAPII TEO TO IH&'T A.ll Ttotf fl.tC:TAICA L WI"' tHO MO t OUiflldENT f~lfAAT f O ~-111\EtH Sl.t.J(t:.T TO fwt f.-0'-C.OW...O C0Ml)0110N$ 1. THAT THf P'ft~OSED lftf$TALLAT•ON SNA\..\. ~t 'N ACC~OANOI 'M't.,_ AWFtOV.ED fiLII"'$ F ILl:() W'tTM THIS OfFW:£ AHO ~~ COH-fQIIIIUtl't' WITH THE NA'ttONAt. eVti..()IN~ CODi. t. ' THAf A OU\.Y LJCENt£tl E:LECTf'\tCAL. IHQINI.IAMASTEA ClAN fE ENOAG(O fO VNOEIITAKl TMl iNII1'ALI.AfiON/c;OHITIOUC. TION
'•
•ucnu.
l.~=T~:;.~~!~/:::1!~~ ~~-=;~~:~: ~~:.:!:~~::.:.:r"A~~~ SHALL
II(•
- - - - . - U-t-LD-,-,..-:-:0-,·-,.-CtA_l_ __ __
SUe&UlTIO MOl I..J'l'lft TH.AH UYIN Cll OAVI AJTIII
-.ntOM OF Tl..atotnAU.AT4 . lltAT A Clftfl,tCATf 0¥ 'INA«. .....I C'tfOH AtCI A C:lATIFtc.Aft OF ~AileY IE MCUiltO rAIOI't fO T"l AaiMLQ(lC<.IIAIOCV Of' TWI DATI .VtiJ)tNO, OIOT1!: TMt$PliWIT MAY If CANCfLUD OlllllV041.(DO\III$0ANf TO SECTIO"U. a :IGlOO TMI "OiolfiOHAL IUILDINGCOM"
340
I'IIOJICl '
DAn
. ---
WIAnmA =---------------
~noN :
OWief" 1oUHIFT
2nd SHIFT
ltd SHifT
~ R"' lmUTY
l'O'!'~
IOUIJOMINT
OI'EIIATIOtf
n ..U TO
IOU TIME
· FROM
I·
NO. OF HOUM
TO
AC!M!JII :
IUINintDaY:
NOTlO IIY:
HiOJiCT tiiOINll II
RlSJOfNT INii'ECTQft
341
,. ----~ i ...
Q -
Ta•u... .., Sidewalk l~~ela~~~re Pa,...it ForM
.act Occupoacy
IIIIWI'OUI NO. 77.01H
Repulollc: oftloo ~ MilliiCry
of l'loblk Waob
OFFICE OF THE BUILDING on1ClA1.
Dittrio:I/City/NIIIUdfllllty 1\lU Code - - - -
Dote IIIIM
Dotelaued TDOORARY SlDEWAut
ENCLOSURE AND OCCUPANCY PERilOT Pllmil ill he~y putt
- - - - - - - --
------
-~~~U---------------------------------~----
Cor 1111 toldolu~ ond occup&M)I of d\e lidcw~ wilh • fron t.,. of . , . - - - - - - - -- - - - - - ( )memund a widlh of ( ) me!enor - - - - - - - - - ~meter. u iDdi<:ated atlhe b1
---------:-:--< i.
2.
The OWUf llld COIItnciOT lbll be toleiy tnpcll\llbe fO< the aafety, pco«cdiolo, l«..nty o n d nieocc of tbc acoe..t publio: 1ft
No enelolurc lblll he mode without lint prmidin& lhe required lempo,.oy sidewalk plulk which shall be
3.
propec!y mamlllifted II aD times.
end_,.
c.,.
The thAII be mode ofwoodcll T.t(;, 26 corrupced G.l.,or any other t.intUas matetiiiJ at lelft two melen (2 .00 M) l\illl, atn~etllrally IOWI4 lll>llluminously paimd for the safety and COli·
....umec ofpedaatriuos. The width of !he lidewalk to be occup;ed shall be 11 indicated atlhe back <>f thla ptrlllil. The borlzoolllloflath oflboiHICIOOUIO'I&Id plonk th.,l notexlnd beyond lhe affected .,.., of tJoe pllllject. 4.
No commen:illo91 wha~r th.U be ptintocl on, an ectled to orditplayed ot tJw 1 i~walk enclosu#.
5.
nus penni! mu•t be kept at lhe jobaiw at all lime• for 1M dunlion of lhe project . l 1 may be tlllceiUd or mabel pUCIUUII to S.Ctloos 305 10d 306 of the NatiooW. Buildln8 Code (P .D. I096) or when pub& IDietellar> ~~~~ct..
F..: O. R. No.
hoo&ed:
342
Ap,ilc..._ for Mec..•lcel Pe""&t Fol'lll
Appendix 10 -
IIIPUIUC 01 TMIIIMIU,.._I MlllttTIIY OP ,U8LIC 110111tl IJ/IfiCI Of T. . eiiiUIM Of,ICIA~ ~ICil,.~t?Y
....... 0 0 1 1 1 - - - - -
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to pettlne11t pto¥llloM of die Mldaell lllldlfttCodt(P..D. to96)tftdlll lmple!Matint ..._lllld ......I!JoM ... to the ,....,. coMitlalll:
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6. Tht worica 1111111 M dcne Uftdcr the IYpervllioe 11f 1 ~llliw (.-, thia Olllee.
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7. thiJpennit mud be kept at tile jobliW II el diDts for the tlumioll of the~ It mq .._ CIIICI6d ~ Jlll-t to Sectioftl30' IIICI 306 of the Nalioallluldit& COlle (P..D. IOK) ...t .e..
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O.Jt.No. r..t: _ _ _ __
UMAGndtFNO.R.No. - - - - li!UII6:-----
IWI'ORTANT: NOTIFY THIS OFFICE AT L!AST 24 HOURS IEfOJtf POURING Of cc:JNC:Ufl.
be...,._ ••Fona Gtou.. Preparation Pe..at
Appendix 13 -
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.......... ,
e-,a c;,_. ..,........
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liillillliilliil
"-aeo41 - - - - - -
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.... ..--...-...,...t ,..,.,....ol......,.......... -----------
__________________ ......,.nld_
- - - - - - - - - - - - - - - - - - f o r tile -IUIIdJcn ofhllr/hlr,..,...,.. ro. 'llllldl• luldlnl (u. ....Type of~) ,.,... .... Ileal ........ for .. ddt Of&e,IUb,lect to tt. , . _ _ c:onclitbli:
I . Tllapmllll._ _____ tilt ,...._, ...... oltt. ,mdpll btiiUit pawtlt _ . , ;.-tl •4 dtlt tbl-/q>pilclnt lht walk or ptqld • ilillher OWft rWI.
.-NIIn
2. Tlla pmn1t 111C1 tt. iopoir: tbll be ...ptlt tlw jallllle • • 3. AI poiiiUc t'dlllll -
.._for. n.t1oe
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Ulllllill tudl • ltMSI, rlidewlib,' culle, ptlen, •leculc ,..., ,.,..., ...
- · ... •lilln, - " ' · - •d d..... !INa and 11M ... llull .. propedy P"*c:fle4 ........
_, ~..,;: oboWcdarl. Alfy fdlty Uld/or 11t8ity UDII,UIIfuli lie proporly ~ _. NlloNd to Ill ...... - - . , . by tilt _,.,.,._. tulljKt to lhe ap,PfOVII ottlie luildJril Oi!ltillllld the
'""" lifthDoUin conceme4. 4.
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1i. _ , llid IXWittliCtot joiftdy !WpOIIIIIIIt fotlhe ..rety, ~. ltCIIIIcy Mel --.ce of . . .-nJ wWk . . ..,.. pe.....t, tbltd puUn, . . - "· eqlllpaieftt,lntt.~Mian ... the like, AD ._..or dJicMW maeerillo f10111 IM,projtct Nil lit .,..,.,ty 11-.1 _, 6lpolr4 'If, W~ter w. . . tbll lie dJildwled dlnctly into dlliN8clllln. Pert!Mat provillou q( the NaUanlllllldlnt CO
._.lie_....,..
S. nil pmd Code (1',D, 10!16).
or IMOU4 ~ to Scc:tlolillOS.: J06 Old. H.riolilll.._.
V..W,•to"" ,.,._..qM•..eo,
341
111£ IWILDlNG OFFICIAL AREA CODE NO - - - 111SS IS TO CERTTFY TKAT TKE CONSTRUC'l'lON OF THE 8Utl.DJN(; COVER£0 BY IUIL.DING PERMrT NO. ISSUED ON HAS BEEN COMPUTm IN ACCORDANCE WITH THE APPROVED PLANS MID SPECIFICATIONS ON FILE WITH 111£ OFFICE OF THE BUILDING OFFICIAL AND THE "NATTONAL BUIWIN(i COD£'' (I' D. 1096). THAT ntt SAJD lnJILDINC AJ'Il)fOR STlUJCTUkE IS R£A0Y FOR FINAL DGI'ECTION FOR 111! ISSUANCE OF THE ''CERTTFICATE OF OCCUPANCY". NAME OF ~ER - - - - - - - - - - - I LAsT NAME)
AODR~OFOWNER
!WIDDLE}
------------------------------------------________________________________
UXAnoNOF~RucnoN
US£ Ofl ME OF OCCUPANCY
DATE OF START Of CONSTRUCTION : PROPOSED
------ACTU.\l. ---------
DATE Of CONPLETION: EXPECTED - - - - - - - - - - - - - - ~-OF n"<*lf:.S
~U.\L - - - - - - - - - - - - -
ACTUALHE~----------------
EmMATEDCOSTf' - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
.-\CltiALCOSf .
f' - - - - - - - - - - - - - CFOII STATlSTICAL rtJaPOSUONLY)
1)
NATERIAI.S(TOTALCOST) f' - - - - - - - - - - - - - - - - - - - - - - 1. CEMENT baas 2. LUMBER (cubic meUt) 3 . REINfORCING BARS (q.) 4 , 1'10. Of G.l. SHEm
b)
DIRECT LABOR (TOTAL COST) P
S. PRE-FAB STRUCTURAL S T E E L { l l & t - - - - - - - - - - - - - - - tiU.SOICUJOESCOMPaf$At10N WIIUHlR IY SALARY OACONT'aACT fOA PkOit:cT AIICiffU.CT/EICGINttk DOWN TO UIORE.U .
c)
R!NTAI.OFEQUIPNENT(IF ANY)
4)
O'mElCOSTS P - - - - - - - - - - - - - - - - - - - - - - - - l"ltiJ JIICLUOU PROFESSIONAL SE:lVICE F'£E.ll, PUMits AHD OTKEJI F£ES.
If CONSTkUC1lON IS UJIID£lTAICiiN aV COHTltACT:
AACtll'll!.CT/CJ\'IL ENGINEER· CIM-QAII
3.C8
Pile ltEC. 1<0. TAN
ADDitESS
COI'ITRAC'TOR CUSS - - - IIEI. C£11T . - - - - -
BIBLIOGUPBY Audel& CUPentt-ra and Builders Guide Vot 2
A'Udels Carpenten and Bwldera Gwde Vol. 3 A\ldels Carpenten and Buildera Guide Vol. " Audels Car.penters and Bullder.t Guide Vol. D Dictionary of Arehite~ and conatnlctiQn by C. H&rJW P1Pe Work and Pipe Welding by L. J. Roae Time Saver Sta.ndard.s for A1'0bit~tu.re Design Data. by Jobn Haru::ock ca.lilender Arebiteetu:ral Graphi~ Standards by Ramsey a.nd Sleeper Slmpltfien Design ot Relnfoteed Concrete by Parker Foundation Engineering by Ralph B. Peek, Walter E. H&DJOO and '.l'bom.aa H. Tbornbum FoWldation Engineering by Leonaa Bnildinc Technology by Willllam J. K~uinnesa, BenJamin S&ebl
Vol. I A II
Desien of Concrete St.ructwe b7 Georse Winte-r; Art.bur H. Nlloll Read-er's DJaest Do it Yourself Reader's Di&e.st Grea.t Enc~ Dlctiona.ey 884~ carpentry lllu.mated How to Do It EneydopediA: by :Mecbani:a woocswortlng lllustmted TeclmolOSY by Hammond, Donnel17. Hurod. Ra.;yner Arebitecture Dra.ftlnl A Des;crt 2nd Ed1tlon b7 Donalc1 E. Hepler
and Pauli. Wallach
Building Code Requirement for Reinforced Concrete ACt Jl&-71 PBJI Steel Technical Da.ta Etemlt T~bnlcal Data Ta~ in Sructural Deetan b7 seaui Steel Coutnlct.lon Jl.&nua}s AISC Tbe Law and Rulea on Phililll)ine Jletrte S,atem The NaUonal Bu114ing COde d tbe Phllippinea aDCl ltll Jmplementinl Rules and Beplationa ACI Beinto.zad Concrete Qeailn Handbook Sim,plitted Deaip .of Stnctura.l Steel by Parker PhJl&teel Intonnatton Jfanual
