Dynamic responses and failure modes of bridge columns under vehicle collision

The dynamic responses and failure modes of reinforced concrete bridge columns under vehicle collision have been numerically investigated in this study by using a numerical model verified against some experimental testing data. The numerical results show that the Peak Impact Force (PIF) from the collision is governed by the vehicle engine and the vehicle velocity while the impulse of the impact force is influenced by the initial momentum of the total mass. It is, therefore, suggested that not only the total vehicle mass and the vehicle velocity but also the engine's weight need to be considered to determine the impact force on structures under vehicle collision. The engine's mass significantly affects the peak impact force, the moment, the shear force and thus the damage of the column. The lateral impact force considerably affects the column axial force and a relation between the PIF and the increase of the axial force is proposed for the design purpose. The numerical model is able to reproduce and provide an explanation of most of the common failure modes observed in real impact events including flexural failure, shear failure, and punching shear damage. In addition, the influences of four different methods of the superstructure modelling, i.e. uniformly distributed load, lumped mass, simplified beam model, and 3D detailed model on the behaviour of the bridge column under vehicle impact are also investigated.