Response surface method for time-variant reliability analysis

A method is presented to efficiently approximate the failure probability of structures subjected to time-variant loads, where the system of loads and structure may have uncertain parameters. The method uses response surface methodology in conjunction with the fast integration technique suggested by Wen and Chen, to provide a limit-state formulation that is computationally simple to solve based on a small number of response time histories. The system reliability may then be quickly computed by first-order reliability method (FORM)/second-order reliability method (SORM) or Monte Carlo simulation. Sensitivity analysis is performed to determine the effect on the failure probability of changes to the system parameters, which can be important when determining whether uncertainty in a given system parameter is significant. An empirical measure of the accuracy of the response surface approximation is presented.