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COMPUTER AIDED DESIGN AND ANALYSIS OF MULTISTOREY

BUILDING(G+20) - USING STAAD-PRO

A Project report onCOMPUTER AIDED DESIGN AND ANALYSIS OF MULTISTOREY BUILDING(G+20) - USING STAAD-

PRO

Submitted in partial fulfillment of the requirement for the award of the degree of bachelor engineering in civil engineering

Kumar Anjneya

Indu Kumari ChowdhurY

Under the guidance

Mr. Anish

OBJECTIVE

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 structuresa. 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

GENERAL

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.

INTRODUCTION A combination of members connected together in

such a way to serve a useful purpose is called Structure.

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 foundation structure.

2. Framed structureFrame structures are the structures having the combination of beam, column and slab to resist the lateral and gravity loads.

Fig 1: Load bearing structureSource: http://www.understandconstruction.com/uploads/1/7/0/2/17029032/3192994_orig.jpg

Fig 2: Frame structure Source:https://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcQL_Mi07nFP4L37DY_25BIgQD8M5NBLk8GdWF4mk15fFelM1V61

The major advantages are:-

1.Thin panels

2.Speed in construction

3.Freedom in planning

4.Better resistant to vibrations

Continued….

 

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

brick wall. 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

earth(ground).• 3ft height parapet on roof.

DESCRIPTION OF THE ELEVATION

PLAN

FRONT VIEW LEFT SIDE RIGHT SIDE

ELEVATION

LOAD CALCULATION

LOAD CALCULATION

Gravity load calculations (self

weight of members, wt. of

walls)

Lateral load calculations(win

d load/ earthqauke)

LOAD TRANSFER MECHANISM IN STRUCTURE

1. Gravity Load Path

2. Lateral Load Path

CALCULATION OF GRAVITY LOADSOur 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.

LOADS ON ROOF LEVELLoad 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 456.

SLAB LOADDead load on slab = 0.127*25 (density of concrete as per is 456 )Water proofing = 2kN/m2

Floor finish = 1 kN/m2

TOTAL DEAD LOAD = 6.175 kN/m2

Live load = 1.5 kN/m2

Wall load Wall thickness =254mmHt. of parapet =0.9144mUnit 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 = 0.254*21.20+2*.012*20.40=5.8744KN/m2

Beam loadWidth of beam=250mmDepth of beam=450mmLoad of beam=0.250*0.450*25=2.8125KN/mFloor beam= 0.125*0.450*25=1.40625KN/m

LOADS ON LINTEL LEVEL  Load on lintel level of 20th floor Beam load=0.250*0.150*25=0.9375kN/m F.B.(C1Q-

C2Q)=0.125*0.150*25=0.46875KN/m Wall on

f.b.=0.127*21.20+2*0.012*20.40=3.182KN/m2

Wall load=5.8744KN/m2 Ht. of wall above lintel= we took 4’ wall Converting wall load to

udl=5.8744*1.2192= 7.16KN/m Wall load on F.B.(C1Q-C2Q)=

3.182*1.2192=3.879 KN/M Net load on lintel beam (beam+wall)

=0.9375N+7.162=8.0995 KN/m Net load on F.B.(C1Q-C2Q) (beam+wall)=

4.34775KN/m

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 load.

Wall load =.254*21.20+2*.012*20.40=5.8744KN/m2

Extra load to be added on beam that carried parapet on roof=5.8744*1.2192=7.162068KN/m

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-C2Q)=3.182*2.1336=6.789KN/m

On balcony side no extra load due to wall.

FLOORHEIGHT 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 42.1121064.05

2  

6 20.1 0.9105 42.7935 1098.77  

7 23.450.9272

543.5807

51139.52

9  

8 26.8 0.944 44.3681181.11

2  

9 30.150.9604

545.1411

51222.63

4  

10 33.5 0.9705 45.61351248.35

5  

11 36.850.9805

546.0858

51274.34

3  

12 40.2 0.9906 46.55821300.59

9  

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 53.61.0257

648.2107

21394.56

4  

17 56.951.0311

248.4626

41409.02

3  

18 60.31.0364

848.7145

6 1423.86  

19 63.651.0418

548.9669

5 1438.65  

20 67 1.0472 49.2184 1453.47  

2170.408

81.0526

549.4745

51468.60

6  

WIND LOAD AS LATERAL LOADSWind 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

only. The influence area for C1R12-C3R12-C5R12 column portion is as following figure

 

Force on the individual memberF= (Cpe- Cpi) x A X Pd ( is 456 part 3, 6.2.1)

Where Cpe= external pressure coefficient.

Cpi= internal pressure coefficient

A= area

Pd= design wind pressure

Calculating Cpe

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-Cpi

value

Aa 0 0.8-(-0.5)

1.3

  90 -0.8-0.5

-1.3

Bb 0 -0.25-0.50

-0.75

  90 -0.8-0.5

-1.3

Cc 0 -0.8-0.5

-1.3

  90 0.8-(-0.5)

1.3

Dd 0 -0.8-0.5

-1.3

  90 -0.25-0.5

-0.75

Calculation of Cpe-CpiMaximum 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 6.2.3.2 pg- 36 IS 875 PART 3 Cpi= +/- 0.5

NODES PZ Cpe F(N)C1R1F1 891.198 1.3 2605.59

LINTEL 891.198 1.34095.03

7       C1R1F2 891.198 1.3

4095.037

LINTEL 891.198 1.34095.03

7C1R1F3 891.198 1.3

4095.037

LINTEL 928.9 1.34268.27

7C1R1F4 966.635 1.3

4441.668

LINTEL1015.70

3 1.34667.13

3C1R1F5

1064.052 1.3

4889.298

LINTEL1081.41

1 1.34969.06

2C1R1F6 1098.77 1.3

5048.826

LINTEL 1119.15 1.3 5142.47C1R1F7

1139.529 1.3

5236.113

LINTEL1160.32

1 1.35331.64

9C1R1F8

1181.112 1.3

5427.184

LINTEL1201.87

3 1.35522.58

2C1R1F9

1222.634 1.3

5617.979

LINTEL 1235.495 1.3 5677.073C1R1F10 1248.355 1.3 5736.165LINTEL 1261.347 1.3 5795.862C1R1F11 1274.343 1.3 5855.582LINTEL 1287.471 1.3 5915.903C1R1F12 1300.599 1.3 5976.226LINTEL 1312.7 1.3 6031.83C1R1F13 1325.4 1.3 6090.186LINTEL 1339.655 1.3 6155.688C1R1F14 1353.91 1.3 6221.189LINTEL 1366.715 1.3 6280.028C1R1F15 1379.52 1.3 6338.867LINTEL 1387.042 1.3 6373.43C1R1F16 1394.564 1.3 6407.994LINTEL 1401.794 1.3 6441.213C1R1F17 1409.023 1.3 6474.432LINTEL 1416.442 1.3 6508.52C1R1F18 1423.86 1.3 6542.608LINTEL 1431.255 1.3 6576.588C1R1F19 1438.65 1.3 6610.568LINTEL 1446.06 1.3 6644.617C1R1F20 1453.47 1.3 6678.666LINTEL 1461.038 1.3 6713.44C1R1F21 1468.606 1.3 2453.879        

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 -0.9F -0.7 -0.7G -0.6 -0.9H -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 70.4088 Pd=1468.606N/M2

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.

Force on node

Force (KN)

C1R1 16.73C2R1 11.999C4R1 17.2860C6R1 9.4699C1R2 6.8538C1R4 2.6705

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 STAADPROGENERATION 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 = 23.368mWidth =23.419mHeight = 70.413m (1.0m parapet being non- structural for seismic purposes, is not considered for building frame height)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:

Supports:

LOADS 1.DEAD LOAD2.LIVE LOAD3.WIND LOAD 4.EARTHQUAKE LOAD

DEAD LOADS LIVE LOADS DEAD AND LIVE LOADS TOGETHER ON STRUCTURE

WIND LOADThe 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 mentioned.STAAD utilizes the following procedure to generate the lateral seismic loads. 

SESISMIC LOAD

 

 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 structure

1.5(dl+ll)+wi1.2(dl+ll+wi) 1.5(dl+ll)+el

LOAD COMBINATION

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 structure  The max reactions and stresses are as follow

Considering the case of wind forces acting on structure

The max reactions and stresses are as follow

Beam no 3759  For earthquake load

Beam no 3759 For wind loads

SLAB NO. 8175

Column no 189 (carrying max reaction at node 117) Column has been designed for max loading i.e. earthquake loading

case

Post processing mode

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 earthquake loading

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.

CONCLUSION

1.IS 4562. IS 875

Part 1 for dead load Part 2 for live loadPart3 for wind load

3.IS 1893 1.2002 CRITERIA FOR EARTHQUAKE RESISTANT4.DESIGN OF STRUCTURES5.Fundamentals for seismic design of rcc building by prof ARYA6.Design of multistory building –by Bedabrata bhattacharjee nit Rourkela7.Analysis of lateral loads –prof S.R. SATISH KR & A.R Santha kumar8.Design of residential building guide9.Load paths –builder’s guide to coastal construction. Fema home building guide10.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

REFERENCES