Time-dependent reliability analysis of corroded existing RC bridges

Rebar corrosion is the primary cause of durability failure for existing reinforced concrete (RC) bridges. Most of the present capacity assessment and reliability analysis for RC structures are developed on basis of the simplified model which only considers the rebar area reduction caused by corrosion with other effects ignored. In this study, a tri-factor time-dependent resistance model for bridge bending capacity analysis is established considering the degradation in rebar area, yield strength and bonding performance. The system reliability of an existing RC bridge is investigated on basis of the practical vehicle load level. The case study shows that the initial maintenance time predicted by tri-factor model could be several decades earlier than that based on the uni-factor model, and the corrosion induced bonding degradation has a significant effect on the time dependent resistance of RC bridge.