Corrosion Fatigue Analysis and Reliability Assessment of Short Suspenders in Suspension and Arch Bridges

Abstract

Suspenders are critical force transmission components in suspension and arch bridges, which connect the girder to the main cable/arch. Field inspection indicates that short suspenders at the midspan or the ends of a bridge may be more prone to fatigue damage under cyclic traffic loads when coupled with the effects of corrosion. The damage has been frequently observed to occur at the lower ends of suspenders. To evaluate the safety of suspenders, a stochastic time-variant reliability assessment method is proposed, where the time-variant model for deterioration of steel wires and probabilistic critical limit states based on crack depth and failure area are integrated, so as to consider the combined effect of corrosion and cyclic loading. A case study on the suspenders of the Jiangyin Yangtze River Bridge was performed in which a finite-element analysis was conducted in conjunction with a comprehensive traffic model. The time-variant reliability indices of the short suspenders were obtained according to the proposed method, which resulted in recommendations for suspender maintenance and replacement.