Fatigue life prediction of stay cables under vehicle load considering corrosion variability

Abstract

The combined effect of environmental corrosion and fatigue loads can accelerate the failure of stay cables. To ensure the safe operation of stay cables, this paper proposed a method for evaluating the fatigue life of stay cables, considering the variability of steel wire corrosion within the cable. Firstly, the relationship between the mean value and the standard deviation of uniform corrosion depth was established based on the experimental data of the corroded steel wires under the artificial accelerated corrosion environment. Then, the model of cable time-vary corrosion under the actual service environment was substituted, and the distributions of the weight loss rate of steel wires were obtained. Subsequently, a method for calculating the fatigue life of stay cables considering the corrosion variability of steel wires in the cable was proposed based on the parallel system theory and the Miner linear cumulative damage criterion. Finally, the North Channel Bridge (NCB) of Hangzhou Bay Bridge was used as an example, and the fatigue life distribution of stay cable under the combined action of corrosion and vehicle load was predicted. The results indicate that considering the corrosion variation of steel wires in the cable leads to a reduction in the fatigue life of stay cables, and neglecting this variability in fatigue life prediction methods is unsafe and non-conservative.