Comparative Analysis of Infilled RC Building Frame with Fixed Base and Flexible Base by Considering SSI for Seismic Load

In conventional approach of analysis and design of structure, the structural engineer consider the base of R.C. building as fixed and avoid the compressible nature of soil. Compressible nature of soil causes decrease in the overall lateral stiffness of R.C. building. This may increase the natural time periods of the structural system. Such increase in lateral natural period, considerably effect the seismic behaviour of R.C. building frame. In this study a G+7 infill masonry RC building is analysed considering effect of infill stiffness using modelling approach given by Hendry for fixed Base and flexible Base. Equivalent static analysis of these two building models is carried out to compare the performance of infill masonry building resting on Raft foundation with fixed base and flexible base by considering Soil Structure Interaction for seismic loading seismic on the basis of Story shear, Floor displacement, Story drift, Time period and Settlement of Raft. Results shows that maximum increases in story shear for flexible base infill frame models compare to fix base infill frame model, displacement for flexible base infill frame is considerably increase compare to fixed base infill frame, story drift is increasing inflexible base infill frames compare to fixed base infill frame. This study also reveals that time period and settlement of raft foundation also increases in case of building with flexible base. This study shows that considering the Soil structure interaction in dynamic analysis of RC building frame the settlement is increased. The effects of soil structure interaction on total and differential settlement is critical factor for soft soil.