Experimental and numerical study on impact resistance of RC bridge piers under lateral impact loading

Abstract

Vehicle collisions with piers are main threat to bridge structures, thus the impact resistance of pier is significant for bridge structure safety. This paper presents the experimental and numerical work undertaken for investigating the impact process, damage and failure mode, dynamic behavior, and impact resistance evaluation method of reinforced concrete (RC) piers under lateral impact loading. By using a horizontal impact system, a series of simplified truck model collision test on the square sectional RC piers are performed, in which two main designing parameters, i.e., impact velocity and longitudinal reinforcement ratio, are especially concerned. Moreover, the detailed finite element models are established by the commercial program LS-DYNA, which are verified against the test results. It indicates that, the shape of impact force time-history does not exhibit the platform stage compared with that of the conventional drop hammer impact tests attributed to the shear failure mode occurred for the present columns; the damage level, impact force, displacement at impact position and energy dissipation rise with increasing the impact velocity; increasing the longitudinal reinforcement ratio improves the impact resistance of RC piers effectively; a plastic hinge forms with the hoop reinforcement yielding before the shear failure of column; the impact force causes a considerable change of the axial force of RC piers during the impact process. Finally, based on the energy conservation law, the residual displacement at the impact position is adopted and validated as the reasonable criterion for evaluating the impact resistance of RC piers. The present work can provide helpful references for the anti-collision design and impact resistance evaluation of the urban and highway bridge piers.