earthquake load comparision on different shapes of · pdf fileearthquake load comparision on...

495 D.K Sharma, Sourav Kr. Agrawal, Shubham Chauhan, Suryakant Singh, Shashank Gupta, RohitKhandare

International Journal of Engineering Technology Science and Research

IJETSR

www.ijetsr.com

ISSN 2394 – 3386

Volume 4, Issue 5

May 2017

Earthquake Load Comparision on Different Shapes of

High Rise Building

D.K Sharma

1, Sourav Kr. Agrawal

2, Shubham Chauhan

2, Suryakant Singh

2,

Shashank Gupta2, Rohit Khandare

2

1Head of department,

2Students, Civil Engineering Department,

ABES Engineering College, Ghaziabad, Uttar Pradesh

Abstract

Tall building utilizes high strength material

which result in limited height of building and it

becomes more slender and flexible with low

damping .This cause discomfort to the building

occupants as flexible buildings are very sensitive

to wind and earthquake load .Therefore to

improve the performance of tall building against

earthquake this research has been done . A tall

building with unsuitable shape requires large

amount of steel or special damping mechanism to

reduce large displacements of buildings .Choosing

the right building shape and architectural

modifications are very important factor to reduce

the earthquake effect . Hence for the research

work , five different shapes of buildings are

studied , namely: square , rectangle , circular,

ellipse , hexagonal for three different heights viz.

75 m, 150 m, 225 m.

To achieve these purposes, firstly a literature survey

with definition of design parameters is considered

for comparison. The results are interpreted for

different shape and different stories and conclusion

is given for the most suitable shape.

Keywords: seismic, base shear, drift, lateral load,

moment

Introduction:

India is developing and emerging as a global

market. Moreover, growing population is

causing a menace to provide shelter to all with a

limited area. So the requirement of tall

buildings, usually designed for office or

commercial use. To build high rise buildings ,

special provisions for earthquake have to be

taken care. Enormous financial investments

are required to build high rise buildings. Only

few researches and studies have been done to

improve against earthquake loads such as

damping mechanism, stiff modification, and

cross section shape. In this research work all

the analysis and results are generated using

ETABS software.

Objective and scope

The main objective of this work is to give the

best shapes of building to control the

earthquake excitation. The parameters for

comparison are base shear, lateral loads,

displacement, drift, moment and shear. The

graphs for comparison of all shapes are given

through which best shape can be chosen.

Earthquake effects on tall buildings

Earthquake causes shaking of the ground. So a

building resting on it will experience motion at

its base. Even though the base of the building

moves with the ground, the roof has a tendency

to stay in its original position. But since the

walls and columns are connected to it, they drag

the roof along with them. The motion of the

roof is different from that of the ground. The

vibration in floors depend upon its natural

frequency compared with frequency of

earthquake.



IJETSR

www.ijetsr.com

ISSN 2394 – 3386

Volume 4, Issue 5

May 2017

Parameters of building

No. of storey 25, 50, 75

Storey height 3 m

Soil type III (loose soil)

Beam size 0.3m*0.6m

Column size 1m*1m

Slab thickness 0.125 m

Concrete grade M40

Steel grade Fe500

Table 1: Parameters

Table 2: Load types

Shape Details :

An unsuitable shape of a building requires great

deal of steel or special damping mechanism.

Thus an appropriate choice of building shape

and architectural modification are important

factors in resisting earthquake forces.

Load Combinations

1 Dcomb1 1.5DL

2 Dcomb2 1.5(DL +LL)

3 Dcomb3 1.5 (DL + LL + HL)

4 Dcomb4 1.2(DL + LL – HL)

5 Dcomb5 1.5(DL+HL)

6 Dcomb6 1.5(DL-HL)

7 Dcomb7 - 0.9DL + 1.5HL

8 Dcomb8 - 0.9DL + 0.3HL

Table 3 : Load Combinations

Figure 1: Square shape



IJETSR

www.ijetsr.com

ISSN 2394 – 3386

Volume 4, Issue 5

May 2017

Table 4

Figure 4: Circular shape Figure 3: Rectangular shape

Figure 5: Hexagonal shape Figure 6: Ellipse shap



IJETSR

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ISSN 2394 – 3386

Volume 4, Issue 5

May 2017

Table 5

Analysis of 25 stories of different shapes against Earthquake

Fig 7:Base Shear Fig 8 :Displacement

Fig 9:Drift Fig 10:Lateral Load



IJETSR

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ISSN 2394 – 3386

Volume 4, Issue 5

May 2017

Fig 11 : Shear LoadTable 6

Analysis 50 stories of different shape against Earthquake

Fig 12: Base shear Fig 13:Displacement

Fig 14 : Drift Fig 15:Auto lateral load



IJETSR

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Volume 4, Issue 5

May 2017

Fig 16:Overturning Moment Fig 17 :Shear load

Comparision of 50 storey

Table 7

Analysis 75 stories of different shape against Earthquake

Fig 18: Base Shear Fig 19:Displacement

1st 2

nd 3

rd

Displacement Circle Ellipse Hexagon

Lateral load Circle Ellipse Hexagon

shear Circle Ellipse Hexagon

moment Circle Ellipse Hexagon

Base shear Circle Ellipse Square



IJETSR

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ISSN 2394 – 3386

Volume 4, Issue 5

May 2017

Fig 20: Auto lateral load Fig 21:overturning moment

Fig 22:shear loadTable 8

Conclusion

1. As per IS 456: 2000, allowable

displacement is H/500 metre. So

allowable displacement for 25 storey

is (25*3)/500 = 150 mm. As all shapes

are under the allowable displacement

with maximum of ellipse up to 100

mm.

2. Overall in 25 storey circular cross

section shows better result. Ellipse can

also be preferred as per aesthetic view.

3. Allowable displacement for 50 storey

is (50*3)/500 = 300 mm.

4. Overall in 50 storey, circular and

ellipse cross section shows better

results.

5. Allowable displacement for 75 storey

is (75*3)/500 = 450 mm. Ellipse has

maximum displacement greater than

450 mm. Thus it cannot be considered.

6. Overall in 75 storey, circular shape

shows better results.

REFERENCES

[1] CTBUH (1980), Council on “Tall Building and

Urban Habitat, Habitat, Monograph on

Planning and Design of Tall Buildings”. Vol.

SC. 1980.

[2] Stafford Smith Bryan & Alex Coul, Tall

Building Structures: Analysis and Design.

John Wiley & Sons, INC, pp. 148-149, 1991.

[3] K.M. Lam, S. Y. Wong & A. P. To,

“Dynamic wind loading of hshaped tall

buildings”. The seventh asia-pacific

conference on wind engineering, Taipei.

Taiwan, 2009.

1st 2

nd 3

rd

Displacement Hexagon Square circle

Lateral load Circle Ellipse Hexagon

shear Circle square Ellipse

moment Circle Ellipse Hexagon

Base shear Circle Ellipse Hexagon



IJETSR

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ISSN 2394 – 3386

Volume 4, Issue 5

May 2017

[4] Wolfgang Schueller, High-Rise Building

Structures. John Wiley & Sons, INC, pp. 243-

244, 1997.

[5] T. Ahmed and J.R. Choudhury “Drift control of

Tall Building Frames.”, Journal of Civil

Engineering, The Institute of Engineers,

Bangladesh. Vol. CE21, No.4, pp. 1-2, 1993.

[6] B.S. Taranath, Strutural Analysis and Design

of Tall Buildings, McGraw-Hill Book

Company, pp. 425-426, 1988.

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