Influence of Soil-Structure Interaction on Seismic Response of Multi-Storey Buildings

In the seismic analysis of a structure resting on the ground, the response of the sub-soil affects the response of the structure and vice versa. Also, the structure displacements and the ground displacements are not independent of each other. This phenomenon is called soil structure interaction (SSI). In this study, to evaluate the effects of SSI on seismic response of multi-storey buildings, three dimensional analyses were performed on moment-resisting frames resting on different soil types with different shear wave velocities and shear moduli, representing soil classes: B, C, and D according to ECP (201, 2011). Three structural models, consisting of five, eight, and ten storey models, have been analyzed using ABAQUS software under two base conditions: fixed base condition, and flexible base condition “considering SSI effects”. Two ground motions (El Centro 1940, and Kobe 1995) have been chosen for the required analysis. The results of the selected cases indicate that base shear forces generally decrease by decreasing the shear wave velocity and shear modulus of the subsoil. Thus, considering SSI effects in the seismic analysis of moment-resisting frames is essential to guarantee both economical and safe design of multi-storey buildings.