Study on corrosion damage mechanisms and fatigue life of corroded steel wires in suspension bridge cable strands

Suspension bridge main cables are critical for bridge safety. Previous studies have not fully quantified the relationship between etch pit depth, stress concentration factor, and fatigue life in corrosion-fatigue performance degradation. This study explores the nonlinear decay relationship among these factors in corroded steel wires of suspension bridge cables. Our innovation is using constant-current accelerated corrosion tests and multiscale finite element modeling (Abaqus/Fe-safe) to systematically quantify this relationship. Results show etch pit depth is the main factor for stress concentration. Each 0.1 mm depth increase raises maximum stress by 8 %–12 %. Fatigue life shows a significant exponential decay trend as etch pit depth increases (R² ≥ 0.91). We suggest a 0.3 mm etch pit depth maintenance threshold. Notably, etch pits under tie-rod bolts in the anchorage zone increase the stress concentration factor by 25 %, reducing fatigue life to 19 % of that in etch pit-free areas. This research supports developing corrosion monitoring and maintenance strategies for suspension bridge main cables and provides a new way to understand steel wire corrosion-fatigue performance degradation.