Effects of Hydrodynamic Pressure on Seismic Response of Continuous Rigid-Framed Bridge

The hydrodynamic pressure caused by inner water and outer water of thin-walled hollow piers under earthquake has an effect on the dynamic response of continuous rigid-framed bridges. In order to investigate the effect, a calculation model for the continuous rigid-framed part of Miaoziping Minjiang bridge, which is based on the finite element theory of fluid structure-interaction, was built by using ANSYS Fluid30 element to simulate water. The seismic response of the bridge was calculated by taking into account the gravity, longitudinal prestress, hydrodynamic pressure, and earthquake waves recorded by the nearest seismic station. The results show that hydrodynamic pressure has little influence on natural frequencies and mode shapes of the continuous rigid-framed bridge, and the maximum reduction rate of the first 30 natural frequencies is approximately 8%, increments of transverse displacement peaks of the box girder reach 10%-20%, the maximum increment of internal force peaks of the main piers reaches 170%, and this value is about 75% for the box girder; and, the earthquake wave acceleration and water depth are the important factors influencing the hydrodynamic pressure.