Shake Table Experiment on Girder-Abutment Pounding Effect and Its Numerical Simulation

Bridge damage due to poundings has been observed in many major earthquakes. It is essential to estimate the pounding damage and to develop a numerical model that can accurately simulate the effect of poundings between a girder and an abutment. First, a 1/20 scale model of the steel pier-RC girder-RC abutment system was constructed and shake table experiments were conducted under different harmonic excitations. The dynamic behavior of the girder and the abutment with poundings were analyzed by comparing the obtained results with those without considering girder-abutment poundings. Second, numerical simulations were developed using a 3-D finite element model with the contact model. The mesh sensitivity and contact types were considered. The experimental results show that considering the pounding effect can reduce the strain in the steel pier and abutment. In addition, damage to the abutment and back wall is not severe even if the frequency of the harmonic shake table movement coincides with the natural frequency of the girder-pier system. The numerical simulations show that the pounding behavior can be well described with the Mortar contact algorithm. The displacements and accelerations of the bridge deck and the strain at the pier agreed well with those from the shake table experiments.