Higher-order failure probability calculation using nonlinear approximations

Use of approximations for calculating the structural failure probability under uncertainties is a necessary aspect. But efficient use of suitable approximations at different stages of reliability prediction and design makes this valuable tool practical for many large scale structures. The objective of this paper is to address the modern approximation concepts and their utility in structural reliability estimation. Emphasis is placed on building the higher order approximations using intervening variables to closely represent the nonlinear limit state functions. The most probable failure point (MPP) search can be carried either in X-space or U-space for a wide variety of random Variable distributions. Several test problems with highly nonlinear performance functions are used to demonstrate the accuracy of the proposed method. (C) 1999 Elsevier Science S.A. All rights reserved.