Soil-Structure Interaction Effect on Seismic Response Modification Coefficient of Dual System Using Substructure Approach

Abstract

Soil mainly affects the dynamic response of structures. Soil-Structure interaction (SSI) is effectively important in case of shear walls according to many international codes. This research aims to study the effect of (SSI) on the dynamic response of dual systems resting on raft foundations using the numerical software engineering program SAP2000. The research methodology relies on studying linear dynamic behavior for models using parameters (number of stories, earthquake frequency, soil type) and using substructure approach in modelling soil to see it’s impact on the overall response and design forces of these systems. Then perform pushover analysis to see the effects of parameters on the response modification coefficient (R). The study showed an increase in the natural period, lateral deflection, internal bending moment in columns of the structure, and a reduction in base shear value compared to the fixed base. The (R) value is different according to the number of stories and type of soil. It is not constant as is mentioned in the Syrian Arab code and ASCE. It increases by 20% in the case of four stories and sand soil compared to codes. The (SSI) increases designing requirements (elements section and analysis time) so it’s a higher cost.