Evaluation of RC Frame Building under Seismic Loading and Base Isolation

Earthquake causes major loss of life and at the same time they also cause huge economic impact in the regions affected. If we look at the recent earthquake that has occurred in and around the world, one can easily highlight the structural inadequacy to withstand seismic forces. Therefore there is an urgent need for assessment of existing buildings which do not fulfil seismic requirement and suffer severe damage under seismic ground motion and also the new structures to be constructed. The aim of evaluating and assessing such buildings is to make them more seismic resistant with the help of techniques like seismic retrofitting and base isolation. This paper presents nonlinear static analysis technique for performance evaluation of 4-storey reinforced concrete residential building subjected to earthquake loading. The performance of the reinforced concrete building is evaluated in terms of maximum base shear, maximum displacement, performance point and sequence of plastic hinge formation. The building considered for analysis is an existing RC residential building located in Mysore designed only for gravity loads as per IS code. The seismic resistance of the building is determined by performing response spectrum analysis and static nonlinear analysis for uniform loading. The building is found that it has more capacity than demand and permissible displacement in Mysore zone hence it does not collapse. Further the push over analysis is carried out for different types of soils and zones and the performance of the building is studied. Base isolation technique is also adopted for 4 storey building. Comparison of results like base shear, time period have been made between the buildings with isolation and without isolation.