Dynamic Response of Superstructure of Prestressed Box-Girder Bridge to Over-High Truck Impact

In order to reveal the damage of the prestressed box-girder bridge caused by over high truck impact, a comparative analysis between a numerical simulation and an impact experiment was conducted to study the dynamic response of the superstructure of a box-girder bridge. A three-dimensional separation model of the prestressed box-girder bridge superstructure, together with the coupling model of the truck and the bridge superstructure, was established using LS DYNA software. With this model, the damage of bridge and truck and the overall displacement of bridge were investigated when the truck impacted the bridge frontally at a speed of 80 km/h, and the dynamic responses of the bridge superstructure to impacts of the over-high truck at speeds of 30, 50, and 80 km/h were compared. The results show that when the truck hit the high mass bridge, the whole bridge damage was little and therefore the study should focus on its local damage; during the collision, the deformation of the truck carriage can result in the transformation of the frontal impact into a punching impact; both the impact force value and the displacement value of the impact area of the bridge are positively correlated with the truck speed, and the maximum displacement is 165 mm when the truck speed is 80 km/h.