Investigation of the impact of cable corrosion on the ultimate strength and fatigue life of stay cable bridges

To investigate the coupled effects of cable corrosion on the ultimate strength and fatigue performance of cable-stayed bridges, sophisticated numerical simulations incorporating established corrosion mechanisms were conducted. Corrosion-induced degradation was modeled through cross-sectional area reduction and material property deterioration, with specific emphasis on wire elongation capacity attenuation. Three finite element models representing steel cable-stayed bridges with distinct spans (300 m, 600 m, and 900 m) were subjected to progressive collapse analysis and fatigue assessment. The results indicate that: (1) Structural failure consistently manifested through plastic hinge formation and fracture at the mid-span girder across all models, accompanied by partial plastification at the tower base; (2) Increased span length elevated cable stress at failure, thereby amplifying the influence of cross-sectional area reduction on ultimate strength; (3) Reduction of wire elongation rate from 4% to 3% or 2% resulted in marginal ultimate strength reductions, whereas attenuation to 1% induced precipitous capacity decline; (4) Under concurrent minimum cable area and elongation rate conditions, the ultimate load-bearing capacity of all bridge configurations experienced an approximate 50% reduction; (5) Corrosion significantly compromised fatigue performance at all cable positions, with localized pitting corrosion exacerbating stress concentration effects and accelerating cross-sectional degradation, consequently diminishing fatigue life.