Safety assessment of gravity load–designed reinforced concrete–framed buildings

A large number of gravity load–designed (GLD) reinforced concrete (RC) buildings are found in many seismic-prone countries including India. Many of them were built before the advent of seismic codes or with the utilization of old and inadequate seismic design criteria. Engineers and decision makers need to have information on the seismic vulnerability of such buildings in a given region for mitigation planning. The present study aims to evaluate the relative seismic vulnerability of a GLD building subjected to seismic hazards in a practical load and resistance factor format corresponding to various seismic zones of India. The results of this study show that the relative vulnerability of the GLD building (with respect to a building designed for seismic forces) shows a multifold increase from lower to higher seismic zone. It also indicates that the GLD buildings existing in higher seismic zones of India (IV and V) should be immediately uninhabited as an urgent mitigation measure.