International Journal of Engineering and Advanced Technology (IJEAT) ISSN: 2249 – 8958 (Online), Volume-9 Issue-4, April 2020 2247 Published By: Blue Eyes Intelligence Engineering & Sciences Publication © Copyright: All rights reserved. Retrieval Number: D6822049420/2020©BEIESP DOI: 10.35940/ijeat.D6822.049420 Journal Website: www.ijeat.org Defining Optimum Location of Shear Wall in an Irregular Building by Considering Torsion Rajiv Banerjee, J. B. Srivastava Abstract- In this paper, the optimum or suitable location of shear wall in a high rise irregular shaped building is determined. The criteria of choosing suitable location are well mentioned with suitable examples. We have tested several models in dynamic analysis with the help of ETABS ver. 16. Both Time History and Response Spectrum Methods are performed in the analysis. The paper clearly specifies the causes of torsion in a high rise building as well as it also specifies the ways in which we can control the torsion and storey displacement with the help of shear wall in the high rise buildings. Keyword: Centre of Stiffness, Centre of Mass, Time History Analysis, Response Spectrum Analysis. I. INTRODUCTION The multi-storey buildings are vulnerable to wind and seismic forces. These forces have the capability to destabilise the structure within a matter of seconds. Thus, making a structure stiffer during these sudden calamities is very important. The lateral stability can be introduced in the building by providing shear walls. Shear walls are the planer structural elements possessing high structural stiffness. These are placed in high rise building with an intention to reduce storey displacement due to the lateral forces. The efficiency of shear wall is governed by its location in a building. When we talk about an irregular shaped building, defining optimum location becomes very difficult. This is because of the fact that, the irregular shaped buildings when subjected to lateral forces triggers torsion because of their geometry. In these cases provision of shear wall in danger zones can trigger more torsion in the building. The shear wall will be like, 'friend turned foe' for the building. Thus, it is very important to study the generation of torsion force in a high rise building. Along with that, we must not forget the use of shear wall, i.e. providing resistance against lateral forces. Thus, optimum location of shear wall can only be decided by considering the torsion generated in the building during the lateral forces. The following point will elaborate the cause of torsion in a high rise building - Before going in details, the following points will be worth noting:  Centre of Mass - It is an assumed point in a building which has equal distribution of mass around itself in all direction. In other words, the point where the whole mass of the building is assumed to be concentrated is called centre of mass. Revised Manuscript Received on April 27, 2020. * Correspondence Author Rajiv Banerjee*, Ph. D student, Dr. A.P.J. Abdul Kalam Technical University, Lucknow. Dr. J. B. Srivastava, Professor, Institute of Engineering and Technology, Lucknow, India. © The Authors. Published by Blue Eyes Intelligence Engineering and Sciences Publication (BEIESP). This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc- nd/4.0/ )  Centre of Stiffness/Rigidity - Like the centre of mass, centre of stiffness is also an assumed point in a building where the resultant stiffness of the building is assumed to be concentrated. Fig. 1 Centre of Rigidity/Stiffness & Centre of Mass (Source: www.slideshare.net) A. Cause of torsion in building – When the centre of mass and centre of stiffness in a building do not coincide, this produces torsion. The change in the location depends on the irregularity in structure. The more are the irregularities, the more is chance of eccentricity (gap between the centre of mass and centre of stiffness). This condition is very common in irregular shaped buildings. Thus, the location of shear wall should be such that, it should not ignite more torsion in the structure. Causes of dislocation of these points –  When the stiffness in one part of the structure is dominant as compared to other areas in the structure, the centre of stiffness shift towards that area, causing an eccentricity in a structure.  The stiffness can increase either through introduction of shear wall or in some of the cases; the building’s irregular geometry causes self triggering of torsion when subjected to seismic forces. II. DEFINING THE CRITERIA FOR DETERMINING OPTIMUM LOCATION The location of the shear wall which will result in reduction of torsional forces as well as the storey displacement will be termed as the optimum location. If the location only exhibits reduction in displacement but produces huge torsion, that will not be considered as an optimum location. III. DETAILS OF THE TESTED MODELS A. Geometrical Details  Length of bays in building frame (uniform) is 5m  Cross- section of beam is 300 X 450 mm  Cross-section of column is 350 X 750 mm