SEISMIC VULNERABILITY ASSESSMENT OF BRIDGES USING FRAGILITY CURVES

Abstract

This study presents the seismic vulnerability of two spanned RCC bridge in Nepal. The bridges vary in span length from 25m to 35m and has a single circular pier in the middle along with two abutments on the sides. The bridge is modeled on finite element analysis-based program OpenSees. Ten different near fault earthquakes are considered for the non-linear time history analysis of the bridge with the drift ratio taken as the parameter to check the damage states (DS) and the performance limits. The pier of the bridge is taken as the most critical component and the fragility curves are developed considering the non-linear deformation concentrated in the pier only. The pier of two spanned bridges of Nepal are highly susceptible to slight damage for the earthquake with 0.5g PGA while slightly susceptible to moderate and extensive damage and are not susceptible to complete damage. Also, at 1.0g PGA, they are highly susceptible to moderate and extensive damage while low susceptible to complete damage.