Abstract:Reinforced concrete bridges withstand both environmental erosions and fatigue loads during operations, resulting in the bridge carrying capacity decay. Through the analysis of the process of steel bar corrosion and fatigue damage, a damage calculation model is set up for evaluation of the comprehensive damage of steel bar’s cross section.Calculation of the hollow plate beam shows that corrosion of steel bar caused a significant reduction in its fatigue life. Therefore, the damage calculation model can provide the basis for the evaluation of the bridge’s time variant load capacity by the coupling effect of both bar corrosion and fatigue damage.