CRITICAL RESPONSE OF MDOF STRUCTURES TO MULTI-COMPONENT SEISMIC EXCITATION

Abstract

Critical response is the maximum value of the response which is obtained under certain loading conditions. In present methods of seismic analysis of structures, the earthquake motion is generally considered in horizontal direction acting along the principal axis of the structure. But, in reality, the earthquake ground motion is not so simple, rather, it is much complex having both translational as well as rotational components. The response obtained by the response spectrum analysis of the structures may not give the maximum response. In fact, there are certain assumptions involved in the generation of response spectrum itself, which may not hold good in actual conditions. Moreover, the time histories which are recorded using various instruments are dependent on the orientation of the instrument with respect to the ground motion. So, this orientation dependent time histories when applied to the structures may not give the maximum response So, the main objective of this project work is to develop such design philosophy by which we will be able to get the maximum response of the structure. For this, a response spectrum shall be constructed which will take into account the orientation dependency and the multi-component nature of the earthquake ground motion