Structural Analysis and Design of Residential Buildings Using Staad

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, eleations, and section, for a residential t(o storey building hae 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 leel under consideration. -or the architectural dra(ings aboe, 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 hae 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$ABS PAE$ %& MAUA$ AA$'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 =ffectie Depth d) 8 h  $c  E:1 Assuming E1mm 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 !roide M1mm N 14;mm c:c %T A Spro 8 341 mm 1:m) A little consideration (ill sho( that this proided area of steel (ill satisfy sericeability 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 inclusie) !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- PAE$ %-

A little obseration (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 !roide 1M5 mm %T A Spro 8 3;1 mm 1) The detailing of eam 9o  is as sho(n belo(<

DESIG O! "#E CO$UMS

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 coered in section 4.# of =$1. The column axial loads hae 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 leel, 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 leel 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 gies the axial load transferred from the beams. -or intermediate supports, note that the summation of the shear forces at the support gies 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 !roide 3M5mm 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 !roided M#N114mm links The column detailing is as sho(n belo(<

DESIG O! !OUDA"IOS

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 imperatie that adeGuate care be taken in the design of foundations. -oundation design starts from detailed field and soil inestigation. 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<

=ffectie depth $oncrete coer 8 4;mm AssumingM1mm 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 )12) 8 ;.2  14 12) 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 proided reinforcement is adeGuate. !roide M1 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 .#K5.3#:12;) 1J#.BB:12;)1L 8 .35 Ohere uo is the column perimeter and d is the effectie depth =d 8 "=d:u;d) 8 .4  2BB.##7  ; 2):312;)  233) 8 .3419:mm 1 "Rd,max 8 ;.4f 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