Study on vehicle impact force on bridge piers: Impact force simplification and distribution characteristics analysis

Vehicle collisions with bridge piers are an important cause of bridge collapse, posing a significant threat to bridge safety. Current standards typically adopt equivalent static forces to represent vehicle impact loads in the collision-resistant design of bridge piers. However, this method overlooks the complex dynamic responses, potentially leading to significant inaccuracies. Therefore, this study investigated the impact force time history of vehicle collisions with bridge piers through numerical simulations. First, the adopted numerical algorithm and material model were validated by simulating drop hammer impact tests. Then, a series of simulation models for vehicle collisions with bridge piers was established, and key variables influencing the impact force time history were determined. Subsequently, a simplified model for predicting impact force time histories was proposed, and regression formulas were developed to calculate model parameters based on the key variables. Finally, the distribution of the impact force along the height and circumference of the bridge pier was analyzed. The results indicate that the proposed simplified model, incorporating key variables such as engine mass, total vehicle mass, impact velocity, and bridge pier diameter, can effectively predict the impact force time history. Additionally, the distribution of impact force along the height of the bridge pier depends on the positions of the bumper, engine, and cargo, with the force mainly concentrated within +/- 20 degrees of the pier centerline. These simplified impact force time histories and the impact force distribution have significant engineering value in guiding the collision-resistant design of bridge piers.