Test and numerical simulation of truck collision with anti-ram bollards

• A medium-duty truck versus anti-ram bollard collision test is presented.
• Impact force and the bollard deflection are shown to increase with increasing the impact speed of the truck.
• When the speed of truck is relatively high, there is a risk that the truck would climb over the bollard.
• A two-degree-of-freedom mass-spring-damper system model is developed to simulate the collision process.

Inelastic transient finite element simulations based on an actual truck collision test are used to investigate the demands imposed during collisions between medium-duty trucks and anti-ram bollards constructed with concrete-filled steel tubes (CFT). The medium-duty truck is considered for crashing into a bollard at speed 50, 65, and 80 km/h, respectively, based on performance demands of bollards of different grades. Numerical results show that both the impact force and the bollard deflection increase with increasing the truck impact speed. When the speed is relatively high (e.g. 80 km/h), there is a risk of the truck climbing over the bollard, even with little damage to the bollard. The analyses show that the impact force along the height of the bollard is not uniform and may change during the impact process. Considering the complexity and computation time consumption, a simplified analysis based on a two-degree-of-freedom mass-spring-damper system model is developed to simulate the collision process. In the analysis, a bilinear spring is used to characterize the truck considering its “soft front and hard rear” characteristics when impacting bollards. Results show that the simplified analytical model is in good agreement with the finite element model using a detailed truck model.