Full 3D modeling of soil structure interaction by using solid finite elements

Abstract

For considering soil structure interaction (SSI) and creating an exact computer model of soils, geotechnical and geological investigations are needed. Since these investigations are neglected for most projects because of different reasons, engineers utilizing the fixed-base concept for analyzing structures. The aim of this study is to present a procedure for modelling a full 3D SSI. For this purpose dynamic responses in terms of base shear and top story displacements of a four story structure was studied. The structure rested on a big soil medium that was numerically modelled in a full 3D manner using solid finite elements, four different soil profiles in the well-known seismic codes were defined (Rock, Very dense, Stiff and Soft soils). Provided information in the codes and the equations of the literature were utilized for numerical modeling.  Finally a comparison study was performed for the dynamic responses, according to the outcome data of the introduced procedure very good results were observed for the models embedded by the two first soil profiles, the responses of the structures embedded by Rock and Very dense soils are minimum affected and minimum deviations were detected, however this effect was increased for the Soft soil profile and reasonable results were seen for the models embedded by Stiff soils.