Fatigue Reliability Assessment of Bridges Under Heavy Traffic Loading Scenario

Uncertainties in traffic flows pose significant challenges for the accurate fatigue safety assessment of bridge structures. Fatigue analysis requires detailed information on heavy vehicle-induced loads, which can be obtained from weigh-in-motion (WIM) systems. This paper develops a stochastic traffic load model based on site-specific WIM measurements to evaluate the fatigue reliability of steel bridges by enhancing simulation efficiency and incorporating correlations in traffic load parameters. Traffic loading is measured on site by WIM systems and used to develop a probabilistic model. A heavy traffic scenario load model is developed based on the Gaussian mixture model (GMM) and Poisson distribution. The correlation between traffic load parameters is addressed using the Nataf transformation. The fatigue reliability of critical components is evaluated using this procedure as an illustrative example. The results show that annual increases in traffic load significantly impact fatigue damage. This research provides a theoretical basis for improved traffic management and structural maintenance strategies.