The Response Analysis Of Deep-water Pier Subjected To The Combined Earthquake And Hydrodynamic Force

The interaction between the deepwater pier and the surrounding water affects the dynamic characteristics and the seismic response of the bridge under earthquake excitation. Currently, there is a lack of adequate understanding of the seismic response of deepwater pier under the combined action of earthquake and hydrodynamic force. The dynamic calculation model of typical round-ended pier used in railway bridges was established by OpenSees finite element software, and the seismic response of pier under the combined action of earthquake and hydrodynamic force was studied. The contents are as follows:(1)Based on investigated the relevant domestic and foreign literatures, the seismic response characteristics of deepwater bridge and the calculation method of hydrodynamic force under earthquake were overviewed, the differences among the railway code, Japanese standard and Morison equation used in calculating hydrodynamic force were compared.(2)The effect of hydrodynamic action on the natural period of the pier is studied.The results show that hydrodynamic force has great influence on the vibration period for pier with larger slenderness, and the effect of hydrodynamic force on low level period of pier is stronger than high level period.(3)The effect of water depth on the elastic seismic response of pier under design earthquake action was studied. The results indicate that hydrodynamic force enhances the elastic seismic response of pier, and the effect of hydrodynamic force on longitudinal seismic response of pier is obvious. The occurrence of peak seismic response value is delayed after considering the action of hydrodynamic force.(4)The influence of water depth on elasto-plastic seismic response and damage state of pier were analyzed under the combined action of high-level earthquake and hydrodynamic force. The results reveal that the increase of water depth has amplification effect on the residual displacement at top of pier and the damage state of pier under high-level earthquake excitation. The residual displacement at top ofpier is increased under near-fault earthquake, meanwhile, the damage degree of pier is deepen and the damage range of pier is extended.