Load‐Space Formulation for Time‐Dependent Structural Reliability

Abstract

A Monte Carlo procedure for reliability estimation of structural systems, subject to multiparameter time‐varying loading and formulated in the space of the load processes, is described. For most realistic reliability problems, this space is of low order, significantly simplifying the required multidimensional integration. The structural resistance is considered to be time‐ and structural‐behavior‐invariant, and is described only in terms of time‐independent, random‐variable strength parameters. The integration to obtain both the outcrossing rate and the zero‐time failure probability is performed using directional simulation of a general type. Example applications are given for loadings modeled as continuous Gaussian processes and for a two‐bay, rigid‐plastic, portal frame structure. Both completely dependent member resistances and member resistances having a given correlation structure are considered. The effect of changes in member strength variance on zero‐time failure probability and outcrossing rate is described. The rate of convergence of the simulation results is noted.