Joints Fatigue Damage Prediction for a Steel Truss Suspension Bridge Considering Corrosion Environment

The corrosion environment of a steel truss bridge significantly shortens its service life, particularly the chemical pollution in the air. A linear corrosion prediction model is proposed based on Miner’s linear cumulative damage concept to solve the difficulty of implementing accelerated corrosion tests. Moreover, an equivalent fatigue test is designed in combination with the corrosion prediction model. The results indicate that the bridge’s fatigue resistance can meet the design requirements when the corrosion environment is not considered. When the corrosion effects are jointly considered, the fatigue durability of the bridge is insufficient. With the increase in fatigue cycles, stiffness degradation presents a three-stage trend. The intermediate stage is a gentle development stage from the fatigue test results, accounting for approximately 80% of the total life cycles. Finally, a fatigue damage prediction model considering corrosion factors is established, and the law of fatigue damage and stiffness degradation of the structure under a corrosive environment is determined.