Analysis And Experiment Of Deep-water Circular Section Pier Seismic Response

With the rapid economic development,a large number of large-span and deep-water bridges havc been built.Compared with the inland bridges,the environment of deep-water bridges are more complicated.And it will not only suffer from the strong wind load,but also encounter the earthquake.When the structure in the deep water is subjected to the earthquake,the hydrodynamic pressure generated by the interaction between the water and the pier will not only change the dynamic characteristics of the structure but also change it s dynamic response.Therefore,it is of great theoretical and practical significance to study the seismic response of deep water pier.In order to simulate the mechanism of the submarine earthquake,we designed the structure of water tank.For the sake of achieving the purpose of delivering a horizontal load to the shaker without passing the vertical load.The tank is supported by a rigid foundation on the ground and connected with the shake table through a horizontal connection plate.In the end,we complete the shaking table test with the designed water tank.This article determined the additional mass coefficient and the additional damping coefficient in the Morison equation by experimenting with the measured acceleration values.Then it studied the relationship between the additional mass coefficient and the additional damping coefficient between the depth ratio of structure into the water,the ratio of the slenderness and the Reynolds number.It is found that the additional mass coefficient incr eases with the depth ratio of the structure into the water.And the additional mass coefficient and the additional damping coefficient decrease as the Reynolds number increases.As for the phenomenon that the additional mass coefficient and the additional d amping coefficient fluctuate in the negative range,it can be interpreted as a cylindrical structure absorbing the certain amount of energy from the water.Nevertheless,no theoretical model can be used to analyze this phenomenon so far.And the question should be further explored by relevant scholars.In this paper,the maximum shear force,the maximum bending moment of the pier bottom and the maximum displacement of the top of the pier are selected.as three basic parameters.Then we analyze the dynamic response of the structure by the finite element software Workbench.The laws are as follows.For one part,For the same diameter of the circular section of the single pier,the dynamic response of the structure increases with the peak acceleration of the earthquake.What’s more,for the single diameter of circular diaphragms with different diameters,the effect of ground moving water is tended to increase with the maximum bending moment at the pier bottom.However,the maximum displacement of the pier has a tendency to decrease.For another part,With the increase in slenderness,The maximum shear force of the pier bottom and the maximum bending moment of the pier bottom are obviously increasing,and the maximum displacem ent amplitude of the pier top increases first and then decreases.Finally,the value of maximum displacement is less than anhydrous situation.The phenomenon indicates that the presence of water will change the dynamic response of the structure,but not necessarily lead to the effect of increasing.Compared with the numerical calculation and the experimental results,it is found that the two trends are basically the same.And the peak of measured acceleration is 0.96 g,the acceleration peak value obtained by numerical simulation is 0.82 g.The error is 14.58 %.