S-N Fatigue Curve Determination for Corroded High-Strength Bridge Wires

Accurate residual life evaluation is crucial for maintenance of corroded bridge wires, and a stress-life (S-N) curve is determined for the fatigue strength of steel wires after corrosion. The S-N curve is established based on assumptions that the maximum pit depth can qualify as an indicator of the corrosion level, and the residual life primarily depends on the crack growth of the corroded wire. By means of the Paris law, the S-N curve is derived for the corroded wires. Intensive reported experimental results from both corrosion acceleration wires and artificially notched wires as well as the corresponding numerical simulation are then used to validate the proposed model. A sensitivity study is also presented to prove the wide applicability of the proposed S-N curve under different factors, including the corrosion pit shape, stress ratio, fatigue loading frequency, and corrosive environment.