The Dynamic Behaviour of Precast Socket Bridge Piers Under Impact at the Pier Top

To investigate the dynamic behavior of reinforced concrete (RC) precast socket bridge piers under impact at the pier top, an impact test on a specimen was conducted. A finite element model for simulating the impact test was established using ANSYS/LS-DYNA and validated by the experimental results. Based on the numerical simulation, the transmission of the internal forces (shear force and bending moment) and the damage mechanism of the socket pier are analyzed. The results indicate that in the initial contact stage, obvious vibration can be found in the time histories of shear forces and bending moments of the pier. Whereas, when the pier-top displacement reaches the maximum value, the distribution of the internal forces along the pier (excluding the socket part) under the impact load is very similar to that under the static loading, i.e., the shear force and bending moment are distributed in a rectangular shape and a triangular shape, respectively. Under the impact load, the maximum bending moment appears at the bottom cross-section of the pier (excluding the socket part), while the maximum shear force appears in the socket part. Consequently, damage to the socket pier is manifested as the bending damage at the pier bottom and the bending-shear damage in the socket part.