SEISMIC STRENGTHENING OF GRAVITY LOAD DESIGNED RC FRAME BUILDINGS

The objective of this study is to identify an efficient retrofitting method for reinforced concrete buildings. Two buildings, one open ground storey with infills and the other partial open ground storey with infills,which were damaged in the January 2001 Bhuj earthquake, were subjected to static pushover analysis with code-specified design shear distribution. The observed failure modes conformed to the actual structural damages sustained by the buildings during that earthquake. The selected methods of retrofitting were, (1) jacketing of columns in the ground storey, (2) structural walls in the ground storey of some selective panels, and (3) structural walls for all the storeys in some panels. These three basic schemes were used in combination for ascertaining an economical method giving the maximum strength and ductility. Of all the methods studied, the combination of column jacketing in ground storey and shear wall throughout the height of the building with selective strengthening of upper storey frame members, gave the most economic and desirable performance