Dynamic reliability analysis of the existing bridges based on probability density evolution method

Existing bridges have experienced time-varying load effects and resistance degradation during the service periods. The complex dynamic loads and diverse failure modes make the existing bridges face high service risks, therefore, it is urgent to make timedependent reliability assessment for the service bridges. The classical time -varying reliability analysis method is increasingly complex and challenging with the increase of the number about random variables. In this paper, probability density evolution theory is introduced as a more advantageous approach to solve the above problem, which is more advantageous for solving the reliability of complex structures with multiple random variables. The dynamic reliability of the existing bridge in serviceability limit state and ultimate limit state is analyzed by considering the bridge resistance degradation and the increase of load effects, as well as the time-varying factors such as shrinkage and creep effect of concrete bridges. The accuracy and computational efficiency for this method are compared with the Monte Carlo method, and the effectiveness of the proposed method is verified, which has the advantages of higher computational efficiency and better accuracy and can be applied to complex nonlinear structures under various loads.