EFFECT OF SHAPE OF TALL BUILDINGS SUBJECTED TO WIND LOADING

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International Journal of Civil Engineering and Technology (IJCIET)
Volume 8, Issue 1, January 2017, pp. 591–601, Article ID: IJCIET_08_01_068
Available online at http://www.iaeme.com/IJCIET/issues.asp?JType=IJCIET&VType=8&IType=1
ISSN Print: 0976-6308 and ISSN Online: 0976-6316
© IAEME Publication Scopus Indexed
EFFECT OF SHAPE OF TALL BUILDINGS
SUBJECTED TO WIND LOADING
T.V.V.S. Murali Manohar
Post Graduate Student, K.L University, Vaddeswaram, A.P, India
N. Jitendra Babu
Assistant Professor, K.L University, Vaddeswaram, A.P, India
ABSTRACT
Objectives: To study the effect and variation of wind pressure with the shape,
rounding of the corners and height of the structure. Methods: Aerodynamic approach is
architecture is the extreme approach in the design of tall buildings. In the present thesis,
multistory buildings of 40 storey, 60 storey and 80 storey were modelled for different
shapes of structures i.e. Rectangular structure, Rectangular structure with rounded
corners, Square structure, Square structure with rounded corners, Circular structure
and Elliptical structure. Findings: The influence of height and shapes on gust loads
and its effects on the response of the structure are studied in the present case. The analysis
of the building has been carried out using standard commercial software (STAAD PRO)
and the estimation of wind loads is done by Indian standard code IS-875(Part-3). The
effect of rounding of the corners of tall structures is studied through computational
fluid dynamics (CFD) on pressure distribution on the surface of the structure. Novelty:
Standard software fluent is used for CFD analysis.
Key words: STAAD. Pro, IS: 456-2000, IS: 875(Part-3), Computational Fluid Dynamics,
Fluent, High Rise Buildings
Cite this Article: T.V.V.S. Murali Manohar and N. Jitendra Babu, Effect of Shape of Tall
Buildings Subjected To Wind Loading. International Journal of Civil Engineering and
Technology, 8(1), 2017, pp. 591–601.
http://www.iaeme.com/IJCIET/issues.asp?JType=IJCIET&VType=8&IType=1
1. INTRODUCTION
The Wind strikes a huge body in its way, it transfers some of its energy to the body. The
amount of energy transferred is measured in the form of a gust response factor. Wind turbulence
is pretentious by high roughness and height above the ground. A tall, lean, and stretchy
structure could have an important dynamic response to wind because of buffeting1, The gust

T.V.V.S. Murali Manohar and N. Jitendra Babu
frequency correlates with the natural frequency of the structure by depending on amplification of
response which also depends on size of the guest relates to the building size2, Tall structures are
more flexible where they are cantilever in nature. Top of the structure will twist, overturn in its own
orbit, tall structures vibrate due to wind turbulence as well as by the structure itself due to the division
of flow. There is a mean of fluctuating response to the winds. The direction of wind plays an important
role in designing the tall structures due to its dynamic effect. The structure across-wind will response
in a wide range of limitations 3,4.
Figure 1 Wind Response Directions
2. OBJECTIVES
The main objective of the present work is to study the effect and variation of wind pressure
with the shape, rounding of the corners and height of the structure. In the present study the
variations of the gust pressure with the shape of the structure on typical multi-storied frames
as per dynamic response factor method is given by the draft code IS-875 part 3 – is studied5,6.
In the present work, multistory buildings of 40 storey, 60 storey and 80 storey were
modelled for different shapes of structures i.e. rectangular structure, rectangular structure with
rounded corners, square structure, square structure with rounded corners, circular structure and
elliptical structure 7. The analysis of the building has been carried out using STAAD Pro. and
the dynamic response factor method, pressures are calculated using Indian standard code IS-
875(Part-3) 8.
The effect of rounding of the corners of tall structures is studied through computational fluid
dynamics (CFD) on pressure distribution on the surface of the structure. Standard software
fluent is used for CFD analysis 9.

Effect of Shape of Tall Buildings Subjected To Wind Loading
3. DIMENSION OF MODELS
Different shapes of buildings of same plan area are modelled. The shapes considered are
rectangular, a rectangle with rounded corners, square, square with rounded corners circle and
ellipse. The centre to centre distance between the columns is 5m. The height of each storey is
3m. The foundation of the building is assumed to be fixed. The plan dimensions of different
shapes of buildings are
• Rectangle 25mx50m
• Square 35mx35m
• Circle radius 40m
• Ellipse 60mx30m (major axis by minor axis)
4. RESULTS AND DISCUSSION
Results obtained from the analysis are deflections, bending moments and axial forces. The
dynamic pressures were calculated according to IS 875 (part-3) using the help of excel sheets.
For the purpose of study, only one column is selected as shown in fig. The Deflections,
Bending Moments and Axial forces are tabulated for those columns. The top floor deflection in
mm, bottom floor bending moment in KN-m, bottom floor axial force in KN of 40 storey, 60
storey and 80 storey rectangular structure of selected column.
The top floor deflection in mm, bottom floor bending moment in KN-m, bottom floor
axial force in KN of 40 storey, 60 storey and 80 storey rectangular structure with rounded corners
of selected column. The top floor deflection in mm, bottom floor bending moment in KN-m,
bottom floor axial force in KN of 40 storey, 60 storey and 80 storey square structure of selected
column. The top floor deflection in mm, bottom floor bending moment in KN-m, bottom floor
axial force in KN of 40 storey, 60 storey and 80 storey square structure with rounded corners of
selected column. The top floor deflection in mm, bottom floor bending moment in KN-m,
bottom floor axial force in KN of 40 storey, 60 storey and 80 storey circular structure of selected
column. The top floor deflection in mm, bottom floor bending moment in KN-m, bottom floor
axial force in KN of 40 storey, 60 storey and 80 storey elliptical structure of selected column.
Figure 2. 40 storey Rectangular +x direction Figure 3. 40 storey Round Rectanglular +x direction

Fig 4. 80 storey Rectanglular +z direction Fig 5. 80 storey Round Rectanglular +zdirection
Figure 6. 40 storey Square +x direction Figure 7. 40 storey Round Square +x direction

Figure 8. 80 storey Square +x direction Figure 9. 80 storey Round Square +x direction
Figure 10. 40 storey circular +x direction Figure 11. 60 storey circular +x direction

Figure 12. 80 storey circular +x direction Figure 13. 80 storey circular +z direction
Figure 14. Variation of roof displacement for different cases with different storey heights
Figure 15. Deflection of rectangular structure

Figure 16. Deflection of rectangular structure rounded at the corners
Figure 17. Deflection of square structure
Figure 17. Deflection of square structure rounded at the corners

Figure 18. Deflection of circular structure
Figure 19. Deflection of elliptical structure
Figure 20. Bending Moment of column no.1 of 40 storey

Figure 23. Axial Force of column no.1 of 40 storey

5. CONCLUSIONS
Based on the analysis conclusions are as follows:
• The bending moments were reduced by an average 70% by rounding of the corners compared
to regular sharp cornered structures. However, as the height of the structure was increasing the
reduction of the bending moment due to rounding of the corners was decreasing gradually.
• The axial forces of rectangular and square structures were decreasing by rounding of the corners
for low heights of the building. But for very tall buildings the rounding of the corners increased
the axial forces in the corner columns.
• The roof displacement of square structures was decreased by about 50 % by rounding
of the corners of the structure but for rectangular structure, the roof displacement was
reduced by an average of 10% by the rounding of the corners. Rounding of the corners was
effective for very tall buildings.
• The circular structure is also most efficient in decreasing the lateral drift of the structure. Elliptical
structures are also effective in reducing the lateral drifts compared to rectangular structures
but not as effective as square and circular structure.
• It was observed from the limited study of computational fluid dynamics that the wind loads acting
on a structure not only depend on the wind velocity and turbulence but also on the shape of the
building. Rounding of corners of buildings reduces the wind forces acting on the building.

Negative forces on the side walls are much greater compared to the windward face of the
structure due to the cross wind effects of the building.
REFERENCES
[1] Shenghong Huanga B, Lib Q S, Shengli X. Numerical evaluation of wind effects on a tall steel
building by CFD. Proceedings of Journal of Constructional Steel Research. 2007; 6, 3612–627.
[2] Yin Zhou, Tracy Kijewski S M, Ahsan Kareem. Along-Wind Load Effects on Tall Buildings:
Comparative Study of Major International Codes and Standards. Journal of structural
engineering. 2002 June; 788-796.
[3] Agerneh K D, Girma T B, Ryan Merrick. Computational evaluation of wind pressures on tall
buildings. 11th Americas conference on Wind Engineering, San Juan. Puerto Rico. 2009 June;
22-26.
[4] Swaddiwudhi P, Khan M S. Dynamic response of wind-excited building using CFD. Proc of
Journal of Sound and Vibration. 2002; 253(4), 735-754.
[5] Shenghong H B, Lib S, Shengli X. Numerical evaluation of wind effects on a tall steel building
by CFD. Proc of Journal of Constructional Steel Research 63 (2007) 612–627.
[6] Li Q S, Fang J Q, Jeary A P, Wong C K. Full scale measurements of wind effects on tall
buildings. Proc of Journal of Wind Engineering and Industrial Aerodynamics 74Ð76 741Ð750
1998.
[7] IS: 875 Part-3, Wind loads on Buildings and Structures – proposed Draft and Commentary,
Published by IITK.
[8] V. Rekha, Vaishali G. Ghorpade and Sudarshan Rao. H, Performance of Lateral Systems on
Tall Buildings. International Journal of Civil Engineering and Technology, 7(6), 2016, pp.550–
557.
[9] Mohamed Fadil Kholo Mokin, R.K.Pandey and Prabhat Kumar Sinha, Performance of Lateral
Systems In Tall Buildings For Varying Soil Types. International Journal of Civil Engineering
and Technology, 5(3), 2014, pp.15–22
[10] An Explanatory Handbook on Proposed IS 875 (Part 3) wind loads on Buildings and Structures.
[11] Taranath B.S. Structural Analysis and Design of Tall Buildings. McGraw-Hill Book Company
1988.

EFFECT OF SHAPE OF TALL BUILDINGS SUBJECTED TO WIND LOADING

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