Dynamic Response and Impact Force Calculation of PC Box Girder Bridge Subjected to Over-Height Vehicle Collision

The dynamic response of a prestressed concrete box girder bridge under the impact of an over-height vehicle is studied using the numerical simulation method. The finite element analysis software LS-DYNA is used to simulate the collision between the bridge superstructure and an over-height truck. Further, a parametric analysis is carried out to investigate the influence of six factors, i.e., girder configuration, vehicle speed, vehicle mass, impact angle, concrete strength and strand prestress, on both local damage and overall performance of the bridge. The numerical analysis results show that the girder configuration, vehicle speed, vehicle mass and impact angle have obvious effects on both local damage and the overall behavior of the PC box girder bridge. Whereas, the concrete strength and strand prestress only have a certain effect on the local damage at the impact area with very limited influence on the overall behavior of the bridge. In addition, based on the results obtained from the numerical simulation and parametric analysis, a formula for predicting the peak and average impact force of the prestressed concrete box girder bridge under the over-height vehicle impact is developed. The proposed impact force formula comprehensively accounts for the influence of the vehicle speed, vehicle mass and impact angle and can accurately predict the impact force generated under different working conditions, which confirms the promising prospect of the proposed formula in practical applications.