SEISMIC PERFORMANCE EVALUATION OF REINFORCED CONCRETE FRAMES WITH VERTICAL IRREGULARITIES

Reinforced concrete multi storey buildings are subjected to most dangerous earthquakes. It was found that main reason for failure of RC building is irregularity in its plan dimension and its lateral force resisting system. The provision of soft storey reduces the stiffness of the lateral load resisting system and a progressive collapse becomes unavoidable in a severe earthquake. In this paper an investigation is made to study the seismic behaviour of a reinforced cement concrete framed structure with and without infills in all the floors and soft storey effect. Infills were modelled using the equivalent strut approach. Non-linear pushover analysis (assigning the hinge properties to beams and column sections) was performed using SAP software. It is observed that seismic demand at the soft storey level is significantly large when infill stiffness is considered, with larger base shear and larger displacements.