Evolution of seismic fragility of reinforced concrete columns subjected to corrosion

Abstract

This paper presents a stochastic methodology to investigate the evolution of seismic fragility for reinforced concrete (RC) columns subjected to corrosion. On account of the increasing variability of mechanical properties of corroded reinforcement, a finite element (FE) model is proposed by incorporating a stochastic constitutive model of corroded rebars. The developed fiberbased FE model is calibrated using a set of experimental data and then extended to conduct pushover analyses and nonlinear time history analyses of RC columns with different corrosion degrees. The results of damage limit states (DLSs) determined by stochastic pushover curves indicate that DLSs for deteriorating columns are corrosion-dependent and follow lognormal distributions. Based on incremental dynamic analyses (IDAs), the fragility analyses results show that reinforcement corrosion has adverse effects on life-cycle seismic performance of RC columns. Comparisons are made between the proposed methodology and traditional approaches to developing seismic fragility curves for corroded RC columns. Considerable underestimations of seismic fragility across different DLSs were found using the traditional approach compared to the stochastic methodology.