Dynamic behaviors and equivalent static force of double-column pier under horizontal impact

The booms in transportation and bridge engineering are accompanied by the increasing threat of vehicular collisions with bridge piers. This study experimentally and numerically examines the dynamic behaviors of double-column reinforced concrete (RC) pier subjected to horizontal impact. Firstly, a series of reduced-scale horizontal impact test on five double-column RC pier specimens (containing the impacted pier, adjacent pier, and bent cap) is conducted considering different impact velocities and mass. Then, based on the previously-validated material models and finite element (FE) analysis algorithms, the five present and twelve additional impact cases are numerically simulated. The test and simulated results indicate that, (i) the whole impact process can be divided into cracking, resiling, and oscillating stages, and the impact force–time history and impact force-lateral displacement curve can be simply characterized by six critical points; (ii) the impact velocity dominates the development of impact force–time history, while the effect of impact mass becomes more significant with impact process progressing; (iii), the damage levels of impacted and adjacent piers as well as bent cap, and the maximal lateral displacement of impacted pier are positively related to the impact kinetic energy rather than the impact momentum. Finally, based on the pier shear resistance and the energy conversion, the novel equivalent static force (ESF) and corresponding ESF-based performance design are proposed for double-column RC pier against horizontal impact. The present work can provide the benchmark test data for validating the FE models, and the determination approach for the ESF-based performance design of bridge piers under vehicular collisions.