Study on Static and Dynamic Reliability of Main Girder of Cable-stayed Bridge Based on Subset Simulation Method

摘要

For failure probability analysis of complex structures, the Monte Carlo method (MC) needs a large number of samples and it is more inefficient in the case of small failure probability. Based on the Subset Simulation (SS) and Subset Simulation Significant Sampling (SSIS), this paper analyzes the static and dynamic reliability of main girder of cable-stayed bridge and realizes the efficient solution of the failure probability of complex cable-stayed bridge. According to SS, MC sampling is performed on random variables. Finally, the critical values of intermediate failure events are solved and automatically stratified, and then the failure probability of each failure mode is obtained by counting the number of samples in the failure domain. According to SSIS method, SS method is optimized by introducing important sampling density function, which can make the sample points to fall in the structural failure areas as many as possible. The failure probability of main girder of cable-stayed bridge can be calculated more efficiently. Meanwhile, ANSYS-PDS template technique is used to perform the reliability and sensitivity analysis of main girder of cable-stayed bridge. The failure probabilities obtained are very close to the results of SS. The example analysis shows that for the reliability analysis of cable-stayed bridges, the sample size of SS and SSIS is 0.3 of MC, and the maximum relative difference is less than 3. In addition the main beam section bending moment and wind speed have the greatest impact on the reliability of the main beam of cable-stayed bridges.