Seismic assessment and retrofitting of existing RC buildings in Kathmandu

Abstract

The effectiveness of reinforced concrete (RC) column jacketing for improving the seismic performance of existing RC building structures were studied. Four three storey buildings with different structural configuration and detailing were selected for seismic assessment and retrofitting purpose. The response of structures (original and retrofitted) was evaluated in terms of capacity curve and inter-storey drift. The case studies also intend to verify the effect of P-delta effects and bi-axial response of columns under non-linear time history analysis. The nature of the capacity curve represents the strong impact of the P-delta effect, leading to a reduction of the global lateral stiffness and reducing the strength of the structure. Finally, a seismic safety assessment is performed based on the drift limit proposed by FEMA-356. The assessment of original building structures indicates that they may exhibit inadequate seismic performance. However, RC column jacketing highly improves seismic performance of all the structures and results maximum drift demand within the drift limit proposed by FEMA-356.