Field testing, analytical, and numerical assessments on the fatigue reliability on bridge suspender by considering the coupling effect of multiple pits
Haiping Zhang, Yu Deng, Yuan Cao, Fanghuai Chen, Yuan Luo, Xinhui Xiao, Yang Deng, Yang Liu
Abstract
The suspender of the bridge is prone to brittle fracture due to the coupling effects of fatigue load and a corrosive environment, and the corrosion-fatigue pits appear random and dense on the surface of high-strength steel wires (HSSWs), which is critical to the life assessment of HSSWs. This study analyzed the influences of different shapes, spacings, and angles of adjacent corrosion pits on the stress concentration factor (SCF). Based on this, a corrosion pit-fatigue crack competition model was established for the bridge suspension rods considering the coupling effects of multiple corrosion pits, and a framework was developed to assess the reliability of corrosion-fatigue of suspension rods on the serving bridge, respectively. The above model and framework were verified by a field test in the Furong Town Bridge, China. It was found that the coupling effect of multiple corrosion pits significantly increases the stress SCF of the corrosion pits. The concentration of chloride ions and the traffic density are the key factors determining the fracture mode of HSSWs. The proposed corrosion-fatigue reliability assessment method is accurate and feasible for bridge suspender HSSWs.