Reliability assessment of existing concrete bridges under the passage of heavy trucks considering bending–shear interaction

As trucks become heavy more frequently in current freight transportation, assessing the structural safety of bridges has become important. However, existing studies focus on the bridge performance subjected to bending or shear failure, neglecting the coupled mechanical behavior of bending–shear interaction. This paper proposes a numerical framework to evaluate the reliability of the existing concrete bridges under the passage of heavy trucks considering bending–shear interaction. First, the probabilistic coupled bending-shear resistances are developed using the modified compressive field theory. Then, a representative overloaded truck model, as well as random truck traffic, is constructed using measured weigh-in-motion data from Chinese freeways. Thereafter, a novel failure path approach based on the minimum distance increment between the total load effect route and resistance envelope curve is presented, which largely simplifies the analysis of bending–shear interaction to a one-dimensional decoupled issue. Finally, the reliability of the bridge is evaluated with respect to single (bending or shear) and coupled (bending–shear) failure modes. The results indicate that the coupled moment–shear failure is more severe than the single failure mode, implying the significance of considering the moment–shear interaction for the safety assessment of girder bridges.