Nonlinear Soil Structure Interaction Analysis of Rigid Tower Subjected to Earthquake Ground Motion

Abstract

Soil-structure interaction (SSI) analysis has gained importance over last few decades. However, during recent earthquakes, many structures performed poorly. Besides many contributing factors for damage, differential settlement has also been the cause for damages, especially in areas where weak soil is present. It is common practice in many earthquake prone areas around the world to analyse the structure using fixed base analysis. This is mainly due to lack of awareness regarding importance of SSI. In order to understand this phenomenon, a study has been performed to show the difference in response when the structure is on fixed base compared to flexible base. Two case studies have been performed to understand the above phenomenon. First case study is on rigid tower on fixed base subjected to pushover loading and earthquake loading and second case same rigid tower but with flexible base with same loading condition. Both the case studies reveal that there is great difference in response due to SSI. In first case, it is observed that structure remain rigid whereas soil media has attained nonlinear state. In case two, soil as well as structure both reached nonlinear state