Soil Structure Interaction Effects on Reinforced Concrete Buildings under Seismic Load

Abstract

The response of a structure during an earthquake depends not only on the structure alone but also on the characteristics of the ground motion and the subsoil conditions. The actual behavior of the structure under seismic load may significantly differ from what the analysis provides considering the structure to be fixed at base. The actual behavior of the structure under seismic load may significantly differ from what the analysis provides considering the structure to be fixed at its base. The present study focuses on the quantification of the effect of soil flexibility on the seismic response of low rise building structures with isolated footing. For the analysis, three dimensional single bay RC building models of one and two storeyes are considered and the soil beneath the structure is modeled as linear elastic model. The transient analysis of the soil-structure model was carried out using the general FEM software ANSYS for El Centro ground motion. Also the static and transient analysis was performed on single storeyed frames to study the variation in the seismic response quantities. Based on the analysis results, it has been concluded that the effect of soilstructure interaction plays a significant role to increase the seismic response quantities like roof displacement, column axial force, base shear and soil settlement. The seismic response parameters like roof displacement, column axial force, base shear and soil settlement increases appreciably with increase in soil flexibility and also with increase in the number of storeys.