Subcycle corrosion fatigue crack growth model for bridge suspender wires under random time-series loads

A damage assessment method for bridge suspender wires subjected to random variable loads is proposed using a subcycle corrosion fatigue crack growth (CFCG) model. The CFCG analysis is conducted by tracking crack tip opening displacement (CTOD) and crack tip plastic zone size in the time-series loading history. The coupling mechanism between corrosion pit growth and CFCG on a time scale is developed based on the rate competition principle. Following this, a corrosion fatigue life prediction model is established by integrating corrosion fatigue damage size including pit depth and crack length. The accuracy and efficiency of the proposed method are verified by experimental and finite element method (FEM) results. A case study is then conducted on the application of corrosion fatigue life prediction of suspender wires using in-situ monitoring data. The results show that the calculation results of the proposed model are in good agreement with experimental and FEM results, with the maximum life prediction error less than 9%. The proposed model can effectively address the problems of model distortion and low computational efficiency caused by cyclic load sequences reconstruction, and provide theoretical support for the damage assessment of bridge suspenders in service.