Damage mechanism and damage evaluation of PC box girder bridge subjected to overheight vehicle impact

Accidental collisions from overheight vehicles often result in significant damage of bridges. To ensure the safety of the bridge structure, it is essential to develop a method to evaluate the damage caused by these impact loadings. This study aims to investigate the damage mechanism of a prestressed concrete (PC) box girder bridge subjected to overheight vehicle impact using the finite element analysis method. Parametric analyses were performed to study the effects of various factors on the impact force and deformation performance of the bridge. In addition, a damage assessment formula, based on the vertical residual bearing capacity, is proposed to evaluate the damage state of the impacted PC box girder. A mass-velocity (m-v) curve is developed to characterize the damage levels of the impacted PC girder under different vehicle velocity and mass conditions. Then, a theoretical equation for predicting the maximum impact force during the vehicle-bridge collision is developed. The numerical analysis results show that vehicle-related parameters have a significant influence on both impact force and local damage of the PC box girder bridge. The proposed mass-velocity (m-v) curve can be used to evaluate the damage state of the PC box girder by relating the performance levels of the girder to each damage index. Moreover, the predicted maximum impact force can be used as an important index to assess the extent of the local damage of the PC box girder.