Reliability-based Fatigue Failure Analysis for Causes Assessment of a Collapsed Steel Truss Bridge

Abstract

This paper is intended to demonstrate conventional and reliability-based approaches to the collapse cause assessment in order to identify the effects of mis-installed bracket and H-beam members on the collapse of a steel truss Bridge over the Han-river in Korea, which is a Gerber-type continuous bridge collapsed in Oct. 1994, only after 15 years since opening to traffic. Based on extensive numerical investigations with parametric studies on various possible failure causes in terms of failure probability and expected fatigue life, it has been found that the mis-installation of bracket and H-beam members accelerated the fatigue failure of the vertical pin-connected hanger. Moreover, It may be observed that both the conventional and reliability-based S-N and LEFM approaches in terms of the expected fatigue life and the fatigue failure probability provide about similar and compatible results. Thus this tendency indicates that any of the reliability approaches could be used as effective and rational technique for the quantitative investigation of the complex collapse causes, together with the aids of conventional S-N / LEFM fatigue analysis.