To investigate the performance degradation of reinforced concrete bridges under multiple factors

the time-dependent evolution process of its resistance and reliability was studied. The effects of carbonization

chloride accumulation

load

and crack on chloride ion erosion were analyzed. According to Fick’s second law and the path probability model

the unconditional probability density distribution of corrosion rate at different service periods was obtained

and then the probability density distribution of resistance corresponding to different service periods was obtained. The three parameter Burr XII distribution model was used to fit it. The Monte Carlo method was used to calculate the reliability probability of the bridge in different service periods

and the effect of the carbonization and chloride accumulation on the probability of corrosion of steel bar as well as the resistance and the reliability of the bridge was studied. The results show that the resistance and reliability of the bridge gradually decrease with the increase of service time

and the dispersion of resistance increase gradually. The resistance and reliability of the bridge reduce when the effect of carbonization and chloride accumulation is considered. The effect of carbonization and chloride accumulation on bridge reliability is mainly manifested in the later stage of service. The influence of carbonization and chloride accumulation should be considered when evaluating the reliability of a bridge that has been in service for a long time.