Comparative Study on Static and Dynamic Analysis of RC Buildings of Different Heights in Different Seismic Zones

Abstract

Reinforced Concrete frame buildings lead the sector of building constructions in urban India. During the lifespan of a building, it experiences different types of static and dynamic forces. Static forces, being time independent in nature, primarily consist of the self-weight of the building. On the other hand, dynamic forces, which include earthquake force, are time dependent in nature. Seismic analysis of RC buildings can be carried out by both static as well as dynamic methods. Static method works on the assumption that the rate of application of the load is too slow to induce significant inertia forces in the structure, while in dynamic method, the inertia forces are taken under consideration. For low to medium rise buildings, static methods only can serve the purpose but for high rise buildings, dynamic analysis becomes crucial as they are affected worst by the earthquake forces. In the modern time, with growing demand and shrinking availability of land, buildings are getting taller and narrower. Hence, dynamic analysis has become necessary in a country like India, which had been shaken badly many times in the past by severe earthquakes causing substantial damage to structures and human life. Equivalent Static Method and Response Spectrum Method, which fall under the category of static and dynamic method respectively, are two of the most widely used methods for seismic analysis. According to Indian Standard codes, Equivalent Static Method is applicable for regular buildings with height less than 15 m in Seismic Zone II and Linear Dynamic Method is applicable for all other buildings. However, in design practice, it is observed that the Equivalent Static Method is also used for buildings of height more than 15 m in various seismic zones. In this paper, multi-storey framed structures of different heights situated in different seismic zones are analysed by Equivalent Static Method and Response Spectrum Method using a structural analysis software and a comparative analysis is performed between the results obtained from both the methods for responses such as bending moments, axial forces, and nodal displacements. Based on the comparisons the more suitable and accurate of the two methods of analysis for RC building is determined.