Analysis on the Damage Assessment Method of Reinforced Concrete Girder Bridge under Collision Based on Trace Theory

Whether the main girder of a bridge hit by a super high vehicle can continue to be used is related to traffic safety. To reveal the damage of the bridge caused by the impact, the damage assessment method of the main girder of the affected bridge based on trace theory and nonlinear calculation theory was studied. First, the collision accident between a super high truck and a reinforced concrete girder bridge was taken as the research object, and a nonlinear finite element model of the vehicle–bridge collision was established by using ANSYS/LS-DYNA software. The posture of the vehicle body and the bridge, and the deformation of the vehicle body after collision were obtained by calculation and analysis of multiple working conditions with super high vehicle weight and impact speed as the variables. The collision speed of the vehicle and the impact force were established by using the method of multiparameter curve fitting. Finally, the damage of the crashed bridge was assessed by inputting the vehicle speed or impact force parameters in the vehicle–bridge collision model, which considers the material constitutive relation. Results demonstrate that, the deformation of the van body is linearly positively correlated with the speed and weight of the impacted vehicle. The average value and the peak value of the horizontal impact force with vehicle weight and vehicle speed are positively correlated, but the correlation ratio is 0. The average value and the peak value of the vertical impact force have a quadratic relationship with the vehicle velocity and the vehicle mass. When the vehicle weight reaches 25 t or the vehicle speed reaches 65 kph, the average value and the peak value of the vertical impact force reach the maximum values. The duration of the impact has a quadratic relationship with the vehicle speed and a nonlinear increasing relationship with the vehicle weight. This study provides a theoretical basis for the damage assessment of impacted bridges.