Soil Structure Interaction Analysis of Multi Story Reinforced Concrete Building

Abstract

Including Soil-Structure Interaction (SSI) in the analysis of reinforced concrete (RC) multi-story building is often ignored in seismic analysis. Considering SSI in the analysis of RC building becomes a challenge for structural engineers.   SAP 2000 v22 has been used as modeling and analysis software.  This software has a new and good capacity to carry out seismic analysis with considering SSI. Three models with different types of soil are considered. The first model rests on hard rocky soil (A conventional fixed base), the second on sand and the third on soft clay soil. The effect of building height is also considered in this study. Time history function was used as seismic excitation (Elccentro1940) earthquake. Both modal and time history analyses are carried out. Numerical results of these analyses with and without soil-structure interaction are compared. A comparison is carried out on three response parameters. These parameters are fundamental natural periods, base shear, and roof horizontal displacement. It is found that SSI analysis influences both modal and seismic responses of the structure quite significantly. Significant variation with number of story in base shear and story displacement is due to coincide of earthquake frequency content and one of natural frequency of building. Finally, SSI analysis is very important to get optimal and economical seismic design of RC multi-story building.