SIGNIFICANCE OF SOIL-STRUCTURE INTERACTION IN SEISMIC RESPONSE OF BUILDINGS

Abstract

In current design office practice, a commonly used modelling assumption is that the base of a building structure can be idealised with fixed support conditions, thereby neglecting any effects from soil-structure interaction (SSI). Various recent studies, however, have shown that the explicit consideration of SSI effects in seismic analysis of buildings structures may significantly affect the predicted seismic demands and resulting structural performance. This study addresses some key issues and practices in the area of SSI and its effects on the dynamic response and seismic performance of buildings. It is also intended to demonstrate the significance of considering SSI effects in structural modelling and analysis while providing key insights into practical applications in real projects. Using a forty storey example building, the effect of considering SSI on the predicted seismic performance is demonstrated. For the purpose of comparison, five detailed computer models (one without considering any SSI effects, two models with SSI modelled using indirect approach, and two models with SSI modelled using direct approach) of the example building were constructed and subjected to various input ground motions. It is observed that depending upon the modelling approach used, the consideration of SSI effects may affect the predicted seismic performance in varying degrees. Moreover, the direct modelling approach presented in this study may provide improved results compared to various approximate methods.