Application of probabilistic fracture mechanics in evaluation of existing riveted bridges

Many existing riveted bridges in China are often required to carry an increasing volume of traffic, usually consisting of vehicles heavier than the original design. Recently Chinese government and engineers have paid more attention to the actual fatigue life and service safety of such infrastructures, and have decided to research evaluation methods using modern technologies. Therefore, based on investigation of fatigue - damage accumulation theory and probabilistic fracture mechanics, the evaluation methods have been developed to calculate the deterministic and probabilistic remaining fatigue life of existing riveted bridges. According to the fatigue failure mechanism of existing riveted bridges, a simple fracture evaluation model and a single-angle probabilistic fracture failure model (SAPFFM) were proposed, and based on Monte-Carlo method, a fatigue reliability analysis program was developed. Finally, as a case study, the fatigue evaluation models were used to predicate the fatigue safety of Zhejiang Street Bridge. According to the evaluation results, the safe inspection intervals and maintenance strategy are determined, which can control and avoid fatigue failure accident in the bridge remaining service life.