Structural Analysis and Design of Residential Buildings Using Staad.Pro, Orion, and Manual Calculations
This should be a long post, but I am going to try and keep it as brief as possible. This post is more like an excerpt from the publication 'Structural Analysis and Design of Residential uildings using Staad !ro "#i, $S$ %rion, and &anual calculations'.... See link belo(). *ere, (e are going to briefly present some practical p ractical analysis and design of some reinforced concrete elements using Staad !ro soft(are, %rion soft(are and manual calculations. +ltimately, (e are going to make some comparisons of the results obtained based on the different methods adopted in the analysis and design. To learn ho( to model, design, and detail buildings from the scratch using Staad !ro, %rion, and manual methods, see the link at the end of this post. To sho( ho( this is done, a simplified architectural floor plans, eleations, and section, for a residential t(o storey building hae been presented for the purpose of structural analysis and design see the pictures belo().
-ig / 0round -loor !lan
-ig.1/ -irst -loor !lan
-ig.2/ -ront "ie(
-ig.3/ ack "ie(
-ig.4/ Right "ie(
-ig.5/ 6eft "ie( The first step in the design of buildings is the preparation of the 'general arrangement', popularly called the 0.A. The 0.A. is a dra(ing that sho(s the disposition of the structural elements such as the slabs and their types, the floor beams, the columns, and their interaction at the floor leel under consideration. -or the architectural dra(ings aboe, the adopted 0.A. is sho(n in -igure 7. belo(. There are no spelt out rules about ho( to prepare 0.A. from architectural dra(ings, but there are basic guidelines that can guide someone on ho( to prepare a buildable and structurally efficient 0.A. To hae a good idea on ho( this can be done, see the link at the end of the post.
-ig.7/ 0eneral Arrangement Design data/
-ck 8 14 9:mm1, -yk 8 35; 9:mm 1, $nom slabs) 8 14mm, $ nom beams and columns) 8 24mm, $nom foundations) 8 4;mm Thickness of slab 8 4;mm< Dimension of floor beams 8 34;mm x 12;mm< Dimension of columns 8 12; x 12;mm) DESIG O! "#E !$OOR S$ABS PAE$ %& MAUA$ AA$'SIS
The floor slab !A9=6 ) is spanning in t(o directions, since the ratio k) of the longer side 6y) to the shorter side 6x) is less than 1.
*ence, k 8 6y:6x 8 2.#14:2.514 8 .;44 say .) &oment coefficients >) for t(o ad?acent edges discontinuous pick from table)< S(ort S)an
&id@span 8 ;.;31 $ontinuous edge 8 ;.;45 $ong S)an
&id@span 8 ;.;23 $ontinuous edge 8 ;.;34 Design of s(ort s)an Mid s)an
& 8 >n6x1 8 ;.;31 ;.B474 2.5141 8 5.;374 C9.m &=d 8 5.;374 C9m =ffectie Depth d) 8 h $c E:1 Assuming E1mm bars (ill be employed for the construction d 8 4; 14 5 8 Bmm< b 8 ;;;mm designing per unit (idth) k 8 &=d:f ck bd1 ) 8 5.;374 ; 5):14 ;;; B 1 ) 8 ;.;7 Since k F ;.57 9o compression reinforcement reGuired H 8 d;.4J K;.14 @ ;.##1k)L 8 H 8 d;.4J K;.14 @ ;.##1 ;.;172)L 8 ;.B4d As 8 &=d:;.#7f yk H) As 8 5.;374 ; 5):;.#7 35; ;.B4 B) 8 22.55# mm 1:m !roide M1mm N 14;mm c:c %T A Spro 8 341 mm 1:m) A little consideration (ill sho( that this proided area of steel (ill satisfy sericeability limit state reGuirements. To see ho( to carry out deflections and crack control erifications, see the the link at the bottom of this post. Result from %rion sho(ing the Short Span mid span) design moments Oood and Armer effects inclusie) !A9=6 )
Result fro* Staad s(o+ing t(e S(ort S)an *id s)an- design *o*ents ood and Ar*er effects inclusi/e- PAE$ %-
A little obseration (ill sho( that the design moment alues from the different methods are ery similar. The full detailing of the floor slabs is as sho(n belo(.
-igure B/ ottom Reinforcement Detailing
-igure ;/ Top Reinforcement Detailing
-igure / Section of the floor slab DESIG O! "#E BEAMS
6et us take eam 9o from our 0A as a design case study/ The loading of the beam has been carried out as sho(n belo(. The beam is primarily sub?ected to load from slab, (eight of (all, and its o(n self (eight. To see ho( to manually calculate the loading on beams, follo( the link at the end of the post.
The internal forces from the loading is as sho(n belo(<
The internal forces from %rion soft(are for eam 9o is as sho(n belo(. 6oad decomposition using finite element analysis (as used for the load transfer.
The internal forces from Staad soft(are for eam 9o is as sho(n belo(.
As 8 &=d:;.#7f yk H) 8 25.55 ; 5):;.#7 35; ;.B4 2BB) 8 13.557 mm 1 !roide 1M5 mm %T A Spro 8 3;1 mm 1) The detailing of eam 9o is as sho(n belo(<
DESIG O! "#E CO$UMS
6oads from slabs and beams are transferred to the foundations through the columns. In typical cases, columns are usually rectangular or circular in shape. 9ormally, they are usually classified as short or slender depending on their slenderness ratio, and this in turn influences their mode of failure. $olumns are either sub?ected to axial, uniaxial, or biaxial loads depending on the location and:or loading condition. =urocode 1 demands that (e include the effects of imperfections in structural design of columns. $olumn design is coered in section 4.# of =$1. The column axial loads hae been obtained by summing up the reactions from all the beams supported by the columns, including the self (eight of the column. 6et us use column A as example. At the roof leel, the column is supporting beam 9o 1 Support Reaction " 8 2.17 C9) and eam 9o 2 Support Reaction "A 8 1.BB C9). At the first floor leel see Analysis and Design of eam 9o and 1), the column is supporting eam 9o Support Reaction " 8 3.2# C9), and eam 9o 1 Support Reaction "A 8 31.3B C9). Therefore the summation of all these loads gies the axial load transferred from the beams. -or intermediate supports, note that the summation of the shear forces at the support gies the total support reaction neglect the signs and use absolute alue. Another method of calculating $olumn Axial 6oad is by Tributary Area Method . This method has not been adopted in this (ork. CO$UM A%
Total $olumns Self (eight 8 1.3 C9 6oad from roof beams 8 2.17 J 1.BB 8 15.15 C9 6oad from floor beams 8 35.1 J 31.3B 8 ##.7; C9 "otal 0 %12.%3 4
Axial 6oad from %rion A) 8 15.5 C9 Axial 6oad from Staad A) 8 2;.5#3 C9 CO$UM A3
Total $olumns Self (eight 8 1.3 C9 6oad from roof beams 8 24.3 J .35 8 35.#7 C9 6oad from floor beams 8 ;4.22 J 5;.#4 8 55.# C9 "otal 0 115.%6 4
Axial 6oad from %rion A2) 8 1;1.2 C9 Axial 6oad from Staad A2) 8 1;.521 C9 CO$UM A5
Total $olumns Self (eight 8 1.3 C9
6oad from roof beams 8 7.B J 4.7; 8 11.#B C9 6oad from floor beams 8 #2.53 J 27.B 8 1.44 C9 "otal 0 %57.58 4
Axial 6oad from %rion A4) 8 44.B C9 Axial 6oad from Staad A4) 8 52.1;7 C9 CO$UM A2
Total $olumns Self (eight 8 1.3 C9 6oad from roof beams 8 32.4 J B.3# 8 41.52 C9 6oad from floor beams 8 2#.15 J 51.34 8 ;;.7 C9 "otal 0 %75.98 4
Axial 6oad from %rion A7) 8 22.B C9 Axial 6oad from Staad A7) 8 3;.2B1 C9 As you can see, for design purposes, the axial loads from the three methods are ery comparable. To see ho( to obtain the column design moments from the use of sub@frames, follo( the link at the end of the post. Design of Colu*n E5
Reading from chart< d1:h 8 ;.1< &=d:f ck bh1 ) 8 ;.;;1 ; 5):14 12; 12; 1 ) 8 ;.;21## 9=d:f ck bh) 8 2BB.## ; 2):14 12; 12;) 8 ;.2;1 -rom the chart/ As-yk ):bhf ck ) 8 ;.;4 Area of longitudinal steel reGuired As) 8 ;.;4 14 12; 12;):35; 8 32.74 mm 1 As,min 8 ;.; 9=d:fyd 8 ;. 2BB.##7):3;; 8 ;.;BB mm 1 F ;.;;1 12; 12; 8 ;4.# mm 1 !roide 3M5mm Aspro 8 #;3 mm 1) $in:s
&inimum siHe 8 ;.14E 8 ;.14 5 8 3mm F 5mm Oe are adopting M#mm as links Spacing adopted 8 1;;mm less than minPb, h, 1;E, 3;;mmQ Result fro* Orion for colu*n E5
Result fro* Staad for colu*n E5
Staad !roided M#N114mm links The column detailing is as sho(n belo(<
DESIG O! !OUDA"IOS
All loads from the superstructure of a building are transferred to the ground. If the foundation of a building is poorly designed, then all the efforts input in designing the superstructure is in ain. It is therefore imperatie that adeGuate care be taken in the design of foundations. -oundation design starts from detailed field and soil inestigation. It is ery important to kno( the index and geotechnical properties of the soil, including the soil chemistry, so that the performance of the foundation can be guaranteed. Analysis and Design of footing E8
earing $apacity of the foundation 8 4; C9:m 1<
=ffectie depth $oncrete coer 8 4;mm AssumingM1mm bars, d 8 3;; 4; 5 8 233mm The ultimate limit state design moment can be obtained by considering the figure belo(<
k 8 &=d:f ck bd1) 8 27.4# ; 5):14 ;;; 233 1 ) 8 ;.;15# designing per metre strip) Since k F ;.57 9o compression reinforcement reGuired H 8 d;.4J K;.14 @ ;.##1k)L 8 H 8 d;.4J K;.14 @ ;.##1 ;.;172)L 8 ;.B4d As 8 &=d:;.#7f yk H) 8 27.4# ; 5):;.#7 35; ;.B4 233) 8 1#5.#5B mm 1:m "o calculate t(e *ini*u* area of steel re;uired <
f ctm 8 ;.2 f ck )12) 8 ;.2 14 12) 8 1.453B 9:mm 1 Table 2. =$1) ASmin 8 ;.15 f ctm:-yk b d 8 ;.15 1.453B:35; ;;; 233 8 3B#.7 mm 1 $heck if ASmin F ;.;;2 b d 337.1 mm 1) Since, ASmin 8 3B#.7 mm1, the proided reinforcement is adeGuate. !roide M1 N 1;;mm c:c A Spro 8 454 mm 1:m) each (ay S(ear at t(e colu*n face
+ltimate 6oad on footing from column 8 2BB.##7 k9 Design shear stress at the column perimeter =d 8 "=d:u;d) is the eccentricity factor see section 5.3.2 of =$1) 8 J .#K5.3#:12;) 1J#.BB:12;)1L 8 .35 Ohere uo is the column perimeter and d is the effectie depth =d 8 "=d:u;d) 8 .4 2BB.##7 ; 2):312;) 233) 8 .3419:mm 1 "Rd,max 8 ;.4f cd 8 ;.5 f ck :14;) L 8 ;.5 14:14;) L 8 ;.43 9:mm 1 f cd 8 >cc f ck ):c 8 ;.#4 14):.4 8 3.57 9:mm 1 "Rd,max 8 ;.4 ;.43 3.57 8 2.#14 9:mm 1 =d F "Rd,max. This is ery ok "rans/erse s(ear at
Oidth of shaded area 8 a d 8 ;.524 ;.233 8 ;.1Bm Area of shaded area 8 .4m ;.1Bm) 8 ;.3254 m1 Therefore, U"=d 8 #B.2#5 J 74.B2B):1 ;.3254 m 1 8 7B.;77 C9 =d 8 "=d:bd 8 7B.;77 ; 2):4;; 233) 8 ;.4214 9:mm 1 "Rd,c 8 $Rd,c k ;;V f ck ):2) J k .WcpL 1d:a) X "min J k .W,subYcp) b(.d $Rd,c 8 ;.#:c 8 ;.#:.4 8 ;.1 k 8 JK1;;:d) 8 JK1;;:233) 8 .7513 Y 1.;, therefore, k 8 .7513 "min 8 ;.;24k 2:1) f ck :1) 8 "min 8 ;.;24 .7513) 2:1) 14):1) 8 ;.3;B3 9:mm 1 V 8 As:bd 8 454:;;; 233) 8 ;.;;531 F ;.;1< "Rd,c 8 ;.1 .7513 ;; ;.;;531 14 ) :2) L 8 ;.22#5 9:mm 1 1d:a) F "min ut in this case, d 8 a *ence, "Rd,c 8 1 ;.22#5 8 ;.5771 9:mm 1 Since "Rd,c ;.5771) Y " =d ;.4;2 C9), 9o shear reinforcement is reGuired. Punc(ing S(ear at 1d fro* t(e face of colu*n
!unching shear lies outside the footing dimensions. 9o further check reGuired. Design Result fro* Orion
The detailing of the footing is as sho(n belo(<
The structural analysis and design of all members hae been fully done, including a step by step tutorial on ho( to model and design on %rion and Staad !ro, and ho( to manually design. See the completed models belo(<
-ully completed model on %rion
-ully completed model on Staad !ro.
