A Project report on
COMPUTER AIDED DESIGN AND ANALYSIS OF MULTISTOREY BUILDING(G+20) - USING STAAD-
Submitted in partial fulfillment of the requirement for the award of the degree of
bachelor engineering in civil engineering
Indu Kumari ChowdhurY
Under the guidance
This project aims at preparing complete RCC design of G + 20 building in Patna. Analysis
and designing will be carried out with the help of AutoCAD, STAAD and manually.
Designs will be as per following codes:
1. IS 456: 2000 code for plain and reinforced concrete Indian Standard Plain and
Reinforced Concrete code of Practice. IS 456: 2000
2. IS:875(1987) code of practice for design loads (other than earthquake) for buildings and
a. Part 1 dead loads b. Part 2 imposed laods c. Part 3 wind load
3. IS 1893 ( Part 1 ) :2002 criteria for earthquake resistant design of structures
The building is a residential building, so there are wall inside
buildings unlike commercial building.
Secondary floor beams are so arranged, that they acts as simply
supported beams and the maximum numbers of main beams get
flanged beam effect.
The main beams rest centrally on column to avoid eccentricity.
The floor diaphragms are assumed to be rigid.
Centre line distances are used in design and analysis.
Preliminary sizes are assumed.
For analysis purpose the beams are arranged to be rectangular so
as to distribute slightly larger moments in columns.
Earthquake loads are the major lateral force acting on structure
and is thus considered.
All the dimensions are in SI units.
A combination of members connected together in
such a way to serve a useful purpose is
1. Load bearing structures
A load-bearing wall or bearing wall is a wall that bears a
load resting upon it by conducting its weight to a
2. Framed structure
Frame structures are the structures having the
combination of beam, column and slab to resist the lateral
and gravity loads.
Fig 1: Load bearing structure
Fig 2: Frame structure
The major advantages are:-
2.Speed in construction
3.Freedom in planning
4.Better resistant to vibrations
PROGRESS OF WORK
The whole work have been done in following steps:
1. Preparation of plans of building using AUTOCAD and locating
beams, columns and providing floor beams as per requirement.
2. Loads calculation and design done.
1. Manually 2. STAAD-pro
DESCRIPTION OF THE BUILDING
The building designed is a multi storey residential building i.e.G+20. The building is
rectangular in shape.
The ground floor is left as a parking space for 80 flats of the building.
Every floor has 4 flats, two 2bhk and two 3bhk.
Plans of all the floors are identical.
Orientation of building is in such a way that the front is facing towards south.
The building has been designed as a RCC framed structure and the type of wall is a
Details of the building has been discussed in two parts
1.Description of the plans
2. Description of the elevation
SL.NO DESCRIPTION VALUE
1. Carpet area 401.91sq metre
2. Built up area 510.60sq metre
3. Super built up area 664.35 sq metre
• Length of the building 23.466m
• Breadth 23.41m.
• Two 2bhk and two 3 bhk on each floor
-In every flat there is one master bedroom with attached washroom.
• Stairs from three sides to serve as subsidiary route for going to roof and other floors,
In case of emergency and others cases like maintenance, painting etc.
• Lift has been provided too along with stairs.
• Between two 3bhk there is hallway, and similar with 2bhk flats.
DESCRIPTION OF THE PLAN
• G+20 building.
• Total height 70.4088m (231ft).
• Height of each floor is 3.35 m (11ft).
• No plinth level as the ground floor rests directly on
• 3ft height parapet on roof.
DESCRIPTION OF THE ELEVATION
weight of members,
wt. of walls)
LOAD TRANSFER MECHANISM IN STRUCTURE
CALCULATION OF GRAVITY LOADS
Our multistorey building has 21 floors including ground floors. Loads on every floors(except
roof),and lintel levels are same so we will be dividing the load calculations in three steps.
1.Loads on roof level
2.Loads on lintel beams
3.Loads on floor.
Load on the roof
consists of parapet load,
roof floor slab load self
wt. Of beam.
Load calculation of slab
on roof has been done
as per triangular and
trapezoidal rule load
distribution as per is
Dead load on slab =
0.127*25 (density of
concrete as per is 456 )
Water proofing =
Floor finish = 1 kN/m2
TOTAL DEAD LOAD
= 6.175 kN/m2
Live load = 1.5 kN/m2
Wall thickness =254mm
Ht. of parapet =0.9144m
Unit wt. of wall = 21.20
KN/m3 (as per is 875 part1)
Unit wt. of plaster = 20.40
KN/m3 (as per is 875 part1)
Load of wall =
Width of beam=250mm
Depth of beam=450mm
LOADS ON LINTEL LEVEL
Load on lintel level of 20th floor
Ht. of wall above lintel= we took 4’ wall
Converting wall load to udl=5.8744*1.2192=
Wall load on F.B.(C1Q-C2Q)=
Net load on lintel beam (beam+wall)
Net load on F.B.(C1Q-C2Q) (beam+wall)=
LOADS ON FLOOR
We will only calculate extra load due to wall and not slab
because we have already calculated load due to slab earlier
& parapet on floor level.
So for places where there are parapet we will be taking
only 4’ wall height because on roof level we have taken 3’
parapet so when we add to it 4’(1.2192m) wall height it
will give wt. of 7’ wall.
At the balcony side it will be only 3’ wall ht. railing so no
need of extra load to be added to roof load to get floor
Wall load =.254*21.20+2*.012*20.40=5.8744KN/m2
Extra load to be added on beam that carried parapet on
Extra load on to be added on beam not carrying parapet on
roof (wall 7’)=5.8744*2.1336=12.5336KN/m
Extra load on to be added on F.B. (C1Q-
On balcony side no extra load due to wall.
FLOOR HEIGHT K2 VZ PZ
1 3.35 0.82 38.54 891.198
2 6.7 0.82 38.54 891.198
3 10.05 0.82 38.54 891.198
4 13.4 0.854 40.138 966.635
5 16.75 0.896 42.112 1064.052
6 20.1 0.9105 42.7935 1098.77
7 23.45 0.92725 43.58075 1139.529
8 26.8 0.944 44.368 1181.112
9 30.15 0.96045 45.14115 1222.634
10 33.5 0.9705 45.6135 1248.355
11 36.85 0.98055 46.08585 1274.343
12 40.2 0.9906 46.5582 1300.599
13 43.55 1 47 1325.4
14 46.9 1.0107 47.5029 1353.91
15 50.25 1.0204 47.9588 1379.52
16 53.6 1.02576 48.21072 1394.564
17 56.95 1.03112 48.46264 1409.023
18 60.3 1.03648 48.71456 1423.86
19 63.65 1.04185 48.96695 1438.65
20 67 1.0472 49.2184 1453.47
21 70.4088 1.05265 49.47455 1468.606
WIND LOAD AS LATERAL LOADS
Wind load calculation
Wind load is a lateral force and acts at nodes only so it
is a nodal force.
The wind speed in the atmospheric boundary
varies with the height from zero at ground level to
maximum at the height called gradient height.
The variation with height depends primarily on
the terrain conditions..
TABLE SHOWING VARIATION OF PZ WITH HEIGHT
Design wind speed= Vz = Vb X K1XK2XK3
K1= Probability factor=1 (is 456 part3 table 1)
K2= varies with height terrain category III, Class C= Varies
with height (is 456 part3 table no.2 pg no. 12)
K3 = topography factor = 1 (IS 456 5.3.3)
DESIGN WIND PRESSURE Pd = 0.6 Vz^2
Vz= 47 x 1 x k2 x1= 47 k2.
AREA CALCULATION FOR WIND LOAD
1.Area for front columns and wall portion
C1R12-C3R12-C5R12 , C9R12-C11R12-C13R12
Area for C9R12-C11R12-C13R12 column portion is same
as the C1R12-C3R12-C5R12 column portion because of
symmetricity so we will calculate area for C1R12-C3R12-C5R12 column portion
The influence area for C1R12-C3R12-C5R12 column portion is as following figure
Force on the individual member
F= (Cpe- Cpi) x A X Pd ( is 456 part 3, 6.2.1)
Where Cpe= external pressure coefficient.
Cpi= internal pressure coefficient
Pd= design wind pressure
As per is 456 part 3 table no. 4 pg.no. 14
L= 23.466M B= 23.14M H= 70.4088M
We have h/w = 70.4088/ 23.41 =3 ; here (3/2)< h/w < 6.
Now l/w = 1.00239 >1 and <(3/2)
From table as per plan
side angle Cpe-
Aa 0 0.8-(-
Bb 0 -0.25-
Cc 0 -0.8-
Dd 0 -0.8-
Calculation of Cpe-Cpi
Maximum values are as follow
for aa side = 1.3 pressure For bb sides
= -1.3 suction
For cc side = 1.3 pressure
For dd side = -1.3 suction
For medium and large openings
188.8.131.52 pg- 36 IS 875 PART 3 Cpi=
Wind load on roof
for roof h/w=(70.4088/23.41)=3: roof angle=0° (
is456 part 3 table 5)
ANGLE = 0° ANGLE =90°
E -0.7 -0.9
F -0.7 -0.7
G -0.6 -0.9
H -0.6 -0.7
After checking for all combinations for max suction=Cpnet=-
1.4 ; No pressure will act only suction will act.
Fnet=-1.4*1*1*1468.606=-2056.0484N/M2 (AT HEIGHT OF
Wind load on frame along G1 and C1
We have calculated influence area for nodes and on multiplying
it with force above we get total force.
WORKING WITH STAAD PRO
STAAD or (STAAD-Pro) is a structural analysis and design computer program originally
developed by Research Engineers International at Yorba Linda, CA in year 1997. In late 2005,
Research Engineers International was bought by Bentley System
Assumptions made in STAAD
1.Roof beams were also designed for the wall loads although there is no wall.
2.All beams were designed for wall loads even if some of them do not carry wall because
selecting specific beams and assigning different load to it is a difficult job in STAAD.
STEPS IN STADD PRO
DESIGN PROCEDURE WITH STAADPRO
GENERATION OF STRUCTURE
All columns = 0.70 x 0.70 m
for earthquake case 0.65X0.65
m for wind load case
All beams = 0.450x 0.250 m
All slabs = 0.127m
Parapet = 0.9 m height
Physical parameters of building:
Length = 23.368m
Height = 70.413m (1.0m parapet being non- structural for seismic purposes, is not considered for building
Live load for all floors is 2kN/m2
Grades of concrete and steel used: Used M30 concrete and Fe 415 steel
Generation of member property:
DEAD LOADS LIVE LOADS DEAD AND LIVE LOADS TOGETHER
The wind load was generated using the primary
load case tab in STAAD pro.
First of all the wind load was defined as per IS
code 875 part 3. The wind load varies with height
and was calculated accordingly. The wind load
being nodal load was assigned from bottom to top
up to height of 70.413m.
The seismic load values were calculated as per
IS 1893-2002. STAAD.Pro has a seismic load
generator in accordance with the IS code
STAAD utilizes the following procedure to
generate the lateral seismic loads.
The structure was analyzed for two cases
a) when wind load acting
b) when earthquake load is acting
load combination taken were
a) When wind load acting b) when earthquake load is acting
Image when all loads were acting on
ANALYSIS OF THE STRUCTURE
The analysis of the structure starts with the concrete designing. The required values of the grade of the reinforcement
as main bars and shear bars ,and stirrups were inserted in the concerned tabs as per is code 456. Commands for
design of beams ,columns, slabs were given in the STAAD.
Fy main = 415000 N/m2, Fy sec= 415000 N/m2, grade of concrete = M30.
Reinforcement ratio = 4%.
Considering the case of earthquake acting on
The max reactions and stresses are as follow
Considering the case of wind forces acting
The max reactions and stresses are as follow
STAAD pro is capable of generating the reinforcement details for each and every column and
beams making use of preset code.
The structure has been designed for two cases wind and earthquake loading case. But in case
of the earthquake loading case the max reaction on the column is coming more than in the
case of the wind load for patna region . so the designing has been done for the case of
Thus for the patna zone the earthquake will be the dominating load
The size of the column is coming around 700x700mm for 21 storey building.
The pattern of the shear bending for one of the sample beam no 3759 is same except that
values are more in case of earthquake loading.
2. IS 875
Part 1 for dead load
Part 2 for live load
Part3 for wind load
3.IS 1893 1.2002 CRITERIA FOR EARTHQUAKE RESISTANT
4.DESIGN OF STRUCTURES
5.Fundamentals for seismic design of rcc building by prof ARYA
6.Design of multistory building –by Bedabrata bhattacharjee nit Rourkela
7.Analysis of lateral loads –prof S.R. SATISH KR & A.R Santha kumar
8.Design of residential building guide
9.Load paths –builder’s guide to coastal construction. Fema home building guide
10.Design of a six storey building iit kharagpur B. Y.Shah department of applied mechanics ms.university of barorda.
11.Wind load distribution on framed structure –Hannah Davies,-mei mathematics in work completion zone.
12.Building frames ce iit kharagpur
13.Rcc project 5 storey building office –Andrew bartolini