NON-LINEAR STATIC ANALYSIS FOR SEISMIC EVALUATION AND RETROFIT. OF RCC BUILDINGS

Abstract

The present study deals with the Non-linear static analysis and retrofitting of RCC buildings. A G+3 storey , stilt RC framed building located at Ahmedabad in Gujarat (Seismic zone-III) has been selected for non-linear static analysis and retrofitting. Pushover approach has been used for non-linear static analysis. Pushover curve is plotted between base shear on y-axis and roof displacement on x-axis. To plot the curve, the base shear is increased at each step and the failed members are removed after every step by providing modulus of elasticity of those members equal to zero. Failure of members is governed by their demand capacity ratios (DCRs). If DCR is greater than 1, it means the member has failed. Pushover curve reflects the strength parameters such as ductility, stiffness, strength, energy dissipated etc. which can not be predicted using linear approach. In addition, it also gives the failure mechanism of the building. Retrofitting of RCC building has been done by jacketing i.e., providing extra reinforcement to failed beams and columns to increase their load carrying capacity. In the present study, the pushover curve after retrofitting is also plotted in x and z direction. It gives a rough idea that ductility, stiffness, strength, energy dissipated of the building have increased after jacketing of the failed members. iii