Seismic Vulnerability Analysis Of High Pier Continuous Rigid Bridge Under The Influence Of Hydrodynamic Pressure

To straddle wider waters,bridges are moving toward greater spans and there are more and more deep-water bridges,the underwater height of the piers of some deep water bridges under construction or completed has exceeded 100 meters.China is an earthquake-prone country,deep-water bridges will encounter the circumstance that the normal land bridges will not appear under earthquakes,as follows: one is the effect of high pier on the vibration characteristics of the structure.Another is when an earthquake occurs,the vibration of the pier causes the surrounding water to sway and water reacts to piers in the form of hydrodynamic pressure to further change the vibration and deformation of the structure,so the pier-water interaction can not be ignored.A large number of literatures have studied the mechanism of pier-water interaction and the seismic response characteristics of deep-water bridges.However,there are few literatures on the seismic vulnerability of bridges with high piers in deep water.Based on this,the seismic vulnerability of the deep water bridge will be studied in this paper,and the characteristics of the high pier and the influence of the pier-water interaction are considered at the same time.The paper mainly did the following works:(1)The current construction situation of deep-water bridges and the necessity of considering the hydrodynamic pressure have been expounded,and the researches related to the seismic vulnerability and hydrodynamic pressure of bridges have been summarized.(2)Taking a typical deep-water and high-pier bridge project as the research object,the finite element model was established,and the effects of higher-order modes and dynamic axial force on its mechanical behavior under earthquakes were analyzed.Meanwhile,the seismic capacity of the bridge structure was analyzed to determine the vulnerable parts of the structure and the corresponding damage indicators.(3)According to the relevant calculation theory of hydrodynamic pressure,the hydrodynamic addition quality of the bridge was calculated,and the seismic demand analysis of the bridge was made at the same time.(4)The fragility analysis function is used to establish the vulnerability curves of the deep-water bridge with high piers under different water depths and different directions of earthquakes.The damage situations of the bridge could be analyzed by these vulnerability curves,and the influence law of hydrodynamic pressure on the vulnerability of deep-water bridge with high piers could be also studied.