Fatigue life evaluation on wire rope suspenders of the suspension bridge based on a time-varying degradation process

Suspenders are critical force transmission components of a suspension bridge and may be more prone to fatigue damage due to environmental aggression and repetitive live loads. To evaluate the safety of the suspender more accurately, a fatigue life evaluation framework of the rope suspender was proposed, where a time-varying fretting-corrosion-fatigue degradation process of the rope wire and probabilistic critical limit states based on failure area were integrated. A case study on the rope suspenders of a prototype suspension bridge was performed under the random vehicle and wind loads, and the reliability indices and fatigue life of the rope suspender were obtained. Results show that the fretting wear had an obvious effect on the degradation process of the wire rope in conjunction with corrosion fatigue, and the fatigue life of the rope suspender would be less than its design life. The proposed method can comprehensively evaluate the service life of wire rope suspenders and provide replacement suggestions more timely, ensuring the safety of the bridge operation.