Effect of Structure-Soil-Structure Interaction on Seismic Response of Adjacent Buildings

Abstract

During Earthquake Ground Motion, adjacent structures interact with each other through the surrounding soil media. This phenomenon is termed as Structure-Soil-Structure Interaction (SSSI). Most of the work reported in literature, in this area, is confined to soft, medium soft and hard soils in foundation. Nothing much is reported on the effect of Sandy-Silty-Clay soils present beneath the foundation of adjacent structures. In this work an attempt has been made to study the response of adjacent structures when founded on such soils. Two adjacent multi-storey buildings of 11 storeys, 36m in height having plan dimensions of 16mx16m are considered in the study. SAP 2000 has been used as modeling and analysis software tool. Raft foundation and soil around the foundation is modelled with 8-noded elastic solid element with three degrees of freedom at each node. The soil mass considered has a size of 1.5 times the width of the foundation along both directions and thickness of 30m. Seismic analysis of two adjacent multi-storey buildings has been carried out for all zones using response spectrum method of IS 1893-2002 (Part-I) considering Structure-Soil-Structure Interaction (SSSI). Single multi-storey building on similar soil strata is also analyzed apart from analysis of conventional fixed base building models for comparison. It is found that adjacent building influences the seismic response of the structure quite significantly under such soil medium present beneath the foundation.