Corrosion Fatigue Assessment of Bridge Cables Based on Equivalent Initial Flaw Size Model

Bridge cables under traffic loads are more prone to failure during the service life due to the corrosion–fatigue coupling effect. In this study, a novel lifespan model based on the equivalent initial flaw size (EIFS) theory is established to analyze the various stages of the lifespan of steel wires. Additionally, a comprehensive corrosion-fatigue lifespan calculation method for parallel steel wire cable is established based on the series–parallel model. A case study of the Runyang Suspension Bridge is conducted to evaluate the evolution of corrosion-fatigue damage in bridge cables during the service life. The results indicate that under the action of corrosion-fatigue, steel wires are more prone to crack initiation, and their fracture toughness is further reduced. In cases where the corrosion level is relatively low, the steel wires of the bridge cables experience no corrosion-fatigue fracture. When the steel wires have initial defects and are subject to corrosion-fatigue conditions, their fracture lifespan is dependent on the severity of the corrosive medium. The reduction in the service life of the cables under the corrosion environment is much greater than that under heavy loads. This research may contribute to the understanding of corrosion-fatigue damage in bridge cables, involving assessment, maintenance, and replacement for bridge cables.