Fatigue life prediction of bridges considering the effect of Multiaxial stresses

Abstract

This paper presents a new low cycle fatigue model to predict life of steel bridges. It consists of Coffin-Manson strain-life curve with a new strain based damage index. The damage variable is based on a modified von Mises equivalent strain to account for effects of loading non-proportionality and strain path orientation in low cycle multiaxial stress state. The proposed model was verified by comparing with experimental test results of two materials. Then, it was applied an existing riveted wrought iron railway bridge to estimate fatigue life due to usual traffic and earthquake loadings. The obtained results verify the importance and effectiveness of the proposed model over commonly used Miner’s rule model in fatigue life estimation of steel bridges.