Seismic Performance Assessment of RC Multi-Storeyed Gravity Load Designed Frames

Abstract

A large number of gravity load designed (GLD) 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 at evaluating the relative seismic vulnerability of GLD building subjected to seismic hazards corresponding to various seismic zones of India. The relative seismic vulnerability of GLD buildings for various site hazard conditions is estimated in a practical ‘load and resistance factor’ format as per the Cornell et al. (2002) guidelines. This simplified methodology is based on the nonlinear time history analysis of the building models considering maximum inter-storey drift as the damage parameter and peak ground acceleration as the intensity measure. Limit state capacities for RC frames are defined for the analysis of all the designed frames. The results of this study show that the relative vulnerability of the GLD building (with respect to a building designed for seismic forces) increases many folds 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.