Corrosion evolution and tensile behavior of wire rope strands in suspension bridges

Pitting corrosion represents a prominent practical threat to wire rope strands of sea‑crossing bridges, which directly compromises the service reliability of suspender components. This work investigates the corrosion‑related mechanical performance degradation of high‑strength steel wires using accelerated corrosion experiments and calibrated three‑dimensional finite‑element analyses. The corrosion evolution exhibits a clear turning point at an equivalent ageing duration of 114 d, where ellipsoidal corrosion pits develop in a divergent growth pattern. Restricted by inter-wire contact, the pit-width growth rate achieves a 95.2 % reduction in the later corrosion stage. Numerical evaluations reveal that the peak local stress increases by 97.8 % when the pit long‑axis rotates to 90° against the axial tensile direction, and pit length produces opposite stress‑concentration responses compared with pit width and depth. This study delivers two major contributions: staged evolutionary characteristics of marine‑environment pitting corrosion derived from laboratory tests, and a previously under‑recognised directional coupling mechanical effect uncovered via calibrated finite‑element modelling. The findings offer practical implications for safety evaluation and maintenance decision‑making of in‑service bridge cables.