Ultimate Collapse Analysis And Reliability Assessment of Frame Structures Due to Multiple Surface Approximation for Failure Condition

Abstract

This paper is concerned with the ultimate strength and reliability analysis of frame structures. The multiple surface approximation for the failure condition of an element is first introduced, which takes account of the nonlinear plasticity codition under biaxial bending moments and an axial force. The failure condition facilitates the more accurate calculation of failure probabilities through the automatic generation of ultimate collapse modes. The so-called branch-and-bound method is applied to select the probabilistically dominant failure modes. Finally, the proposed method is applied to a plane framework under in-plane and out-of-plane loads. Through numerical example, the applicability of the proposed method is demonstrated.