Response of low-rise buildings under seismic ground excitation incorporating soil–structure interaction

Abstract

In the conventional design, buildings are generally considered to be fixed at their bases. In reality, flexibility of the supporting soil medium allows some movement of the foundation. This decreases the overall stiffness of the building frames resulting in a subsequent increase in the natural periods of the system and the overall response is altered. The present study considers low-rise building frames resting on shallow foundations, viz. isolated and grid foundation. Influence of soil–structure interaction on elastic and inelastic range responses of such building frames due to seismic excitations has been examined in details. Representative acceleration–time histories such as artificially generated earthquake history compatible with design spectrum, ground motion recorded during real earthquake and idealized near-fault ground motion, have been used to analyze the response. Variation in response due to different influential parameters regulating the effect of soil-flexibility is presented and interpreted physically. The study shows that the effect of soil–structure interaction may considerably increase such response at least for low-rise stiff structural system.