Reliable Fatigue-Life Assessment of Short Steel Hanger in a Rigid Tied Arch Bridge Integrating Multiple Factors

Abstract

With higher requirements in stiffness and strength, the running safety of high-speed railway bridges is more sensitive to structural damage. Compared with long steel hangers, short steel hangers sustain greater damage under the action of high-speed trains. In this article, a reliable fatigue-life assessment method of short hangers was established and proposed, integrating multiple factors. These factors include bending-axial behavior, environmental corrosion, transverse location of trains, train weight, and traffic flow. As a case study, this method was applied as a reliable fatigue-life assessment of the short steel hangers of the Dashengguan high-speed railway bridge. Using mass strain data measured by structural health monitoring system (SHMS), multiorder Gaussian distributions (MGDs) were first used to obtain the probabilistic distribution of fatigue effects with multiple peaks. The Monte Carlo counting method was then used to calculate failure probability and corresponding fatigue reliability index. The influence of environmental corrosion, train weight, and traffic flow on reliable fatigue-life were finally investigated by comparing fatigue reliability index with the defined target value. Consequently, under the combined actions of environmental corrosion, increase of train weight, and traffic flow, the reliable fatigue-life may be less than 1 years, indicating that the short steel hangers of this bridge may suffer from the significant risk of fatigue cracking during the design life of the bridge.