Importance of inclusion of soil–structure interaction studies in design codes

Abstract

The Indian seismic design code IS:1893 (Part 1) (BIS, 2002) suggests ignoring soil–structure interaction (SSI) studies for seismic design of structures located on rock or rock-like material. However, for a structure resting on soil, it is imperative that the interaction effects be considered during its analysis. The current study is aimed to assess the differences in the design response and analysis outputs arising due to inconsideration of SSI in the analysis for building frames. Reinforced Concrete (RC) building frames supported on pile foundation and embedded in loose sand are considered and finite element analysis is performed using the OpenSees program. Five types of analysis have been carried out to estimate the different design response and analysis output parameters. The study highlights that it may not always be feasible to ignore time history analysis in cases where site response influences the overall response of the building–foundation–soil system. Thus, detailed investigation is required on possible incorporation of dynamic analysis in code-prescribed seismic design procedure.