Comparison of Influence of Earthquake and Wind Forces on High-Rise Multi Story Structures

Abstract

This study offers a comparison of the impact of earthquake forces and wind forces on a multi-storey structure. The performance of the structures under seismic and wind loads plays a significant role, influencing not only structural integrity but also the safety of individuals residing within the structure. Studying the effects and behaviour of multi-storey buildings during seismic loading is a significant challenge. It is crucial to take into account the impacts of lateral loads when designing reinforced concrete structures. It establishes the essential design loading for multi-storey structures exposed to earthquake zones (II, III, IV, and V) and varying wind speeds. This study analyses the behaviour of high-rise multi-storey buildings under earthquake loads according to IS 1893:2016 and wind loads as per IS 875 part-3:2015. When a structure is located in a specific earthquake zone, the primary design loads for that building can be determined utilizing these findings. Following an in-depth analysis, the structures experience greater impact from earthquake forces in zone V and a lesser impact in zone II.

Introduction

As the height of a building increases, the lateral forces from earthquakes and wind also increase, impacting the building’s rigidity, stability, and overall structural design. Tall buildings must be designed to resist these lateral forces through adequate strength and stiffness to prevent excessive swaying, vibrations, and potential collapse.

Earthquakes and wind are unpredictable natural disasters that significantly influence the design of high-rise structures, especially in seismic zones. Seismic loading, often more critical than wind loading, dictates the form and final design of buildings in high-risk areas to minimize life and property loss.

The project aims to study and compare structural responses—such as story shear, lateral deflections, story drift, and reinforcement requirements—of tall buildings under different seismic zones and wind speeds in India using ETABS software. It also investigates how these forces vary with building height and environmental conditions.

The methodology includes dynamic seismic analysis (using Time History and Response Spectrum methods) and wind load analysis based on Indian standards, considering seismic zones II to V and wind speeds up to 55 m/s. Seismic base shear is calculated per IS codes, and lateral forces are distributed throughout building height.

Key observations show that as seismic zone severity and wind speed increase:

• Story shear increases by up to 45% for earthquakes and 57% for wind.

• Lateral displacements increase up to 50% (earthquake) and 40% (wind).

• Story drifts increase significantly with seismic intensity.

The study highlights the critical importance of properly assessing lateral forces for designing safe and resilient tall buildings in seismic and high-wind regions.

Conclusion

In this study, the multistoried building excited to earthquake and wind forces for different seismic zone and varying wind forces are studied. From the modelling and analysis of these building, the following conclusion are drawn out. 1) The wind forces are found equally dominating for the high rise building. 2) As the earthquake zone increases, the displacements and story shears rise. The tall structures are similarly affected by wind and seismic forces, and the impact of the wind grows as their height increases further. 3) It is noted that the lateral forces acting on the structure have exhibited greater intensity with a rise in wind speed and earthquake zone factor. 4) It is observed that, the lateral forces excited on the structure have shown increasing severity with increase in the wind speed and earthquake zone factor. 5) When earthquake force effects observed on the buildings, the low rise buildings shows higher influence to earthquake forces when compared to high rise building. 6) When wind force effects observed on the buildings, the low rise buildings shows lesser influence to wind forces when compared to high rise building. 7) When evaluating response parameters influenced by wind and earthquake forces for structures of identical height, it has been noted that seismic zone V largely resembles the impact of a wind speed of 50 m/sec. 8) From this, it can also be concluded that, for tall building design ,both earthquake and wind forces need to be taken into account with great attention considering appropriate design loads.

References

[1] Behavior of reinforced concrete walls under the impact of Earthquake force by Dr.Sudhir Kumar Jain. [2] Earthquake resistant design of structure by Shrikhande, Manish Agarwal, Pankaj. [3] Earthquake Dynamics of Structures by Anil. K. Chopra. [4] Reinforced design of Tall Building by S. Taranath. [5] Earthquake Tips authored by Prof. C V R Murty, IIT Kanpur and sponsored by Building Materials and Technology Promotion Council, New Delhi, India. (Source: www. www.iitk.ac.in) [6] Earthquake Engineering Practice, Volume 1, Issue 1, March 2007, published by National Information Center of Earthquake Engineering, IIT Kanpur, Kanpur 208016. [7] Earthquake resistance design of structure by Duggal- Oxford University Press. [8] Zynamics of structure by Clough R.W. and Penzin J. McGraw Hill Civil Engineering Series [9] Dynamics of structure by Mario Paz, CBSPD Publication [10] Earthquake Resistant Design by David J. Downik, John Wiley and Sons Publication [11] Earthquake Tips NICEE, IIT, Kanpur [12] Elements of Earthquake Engineering by Jaikrishna and Chandarsekaran. [13] Geo-technical Earthquake Engineering by Kramer S. L. Prentice Hall India Publication [14] Introduction to Structural Dynamics by John M. Biggs [15] Mechanical Vibrations by V. P. Singh

Copyright

Copyright © 2025 Mr. Asok Chakrabarti . This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.