Effects of soil-structure interaction on multi storey buildings on mat foundation

Abstract

OThe analysis of the interaction between structural foundation and supporting soil is of fundamental importance for structural engineers. The present Indian standards for distribution and transfer of loads from superstructure to the soil assume rigid connection between foundation and soil. This is attributed to the perception that neglecting the effects of soil-structure interaction (SSI) leads to a conservative design. However its effect becomes significant for certain class of structures such as high rise building subjected to dynamic loads. Results of such analyses provide information which can be used in the structural design of foundation. Multi-storey symmetric buildings have been modeled and subjected to seismic load. Finite Element Method was employed to compare the response of the structure under various load combinations for two cases: one with a rigid foundation soil connection and the other taking considerations of foundation-soil flexibility. Fictional contact has been used to imitate SSI effect. The results obtained showed increase in displacement at different storey when SSI effects are taken into account. Higher value of storey drift has been observed at lower heights. This study reveals that the behavior of structure changes with the change in nature of interaction between soil and foundation elements. Soil-structure interaction may become critical in some cases, however, uncertainties too exists with SSI. Hence a comprehensive and extensive method of analysis has to be devised for accurate analysis, and an economical and conservative design. © Springer India 2015. All rights reserved.