Dynamic Response Analysis Of Pier Under The Action Of Water Flow

There are many rivers and mountains in our country.When Bridges cross rivers and lakes,its piers are buffeted by water.Especially during the flood,the impact of water flow on the pier is particularly significant.Researcheers our country and foreign scholar have carried out a statistical investigation on the damage caused by water flow,the results show that the impact of water flow has become one of the main reasons for the destruction of bridges.Therefore,the effect of water flow on the dynamic response of piers is worth exploring.This article is based on the theory of fluid and structural vibration,using the fluid analysis software Fluent to analyze the three-dimensional flow around the double thin-walled pier,with the software to calculation of the impact load of water flow on the pier under different water depth and different flow velocity.On this basis,based on the Ansys workbench platform,the flow impact load is applied to the finite element model of bridge pier through data transmission between different modules.The dynamic response of bridge pier is calculated in the structure transient analysis module,and the influence of velocity,depth,constraint condition and scour depth on dynamic response of bridge pier is investigated.The aim of this paper is to provide a three-dimensional numerical simulation method for the study of the fluid-solid coupling problem of flow impact structure.The main research contents are as follows:1.Selection of flow field and pier typeThe two-dimensional flow around circular pier,round end pier and rectangular pier is studied by using the fluid analysis software Fluent.Under the same conditions,the flow field was analyzed to determine the most unfavorable pier type.In order to select the appropriate pier type,three types of single and double piers were established respectively,and the influence of the distance between the two piers on the drag coefficient is analyzed.2.Verification of 3D flow field calculation methodTaking the three-dimensional flow around the Reynolds number Re=3900 as an example,based on large eddy simulation methods to analyze the distribution of the three-dimensional flow field,The results of the calculation are compared with the values of the reference to verify the accuracy of the three-dimensional flow field calculation method.3.Analysis of influencing factors of dynamic response of piers under water flowTaking a rectangular double thin-walled bridge pier as an example,a three-dimensional finite element model is established,and the interaction between the pier and the soil is simulated by the soil spring,and the dynamic response of the pier under the impact of the flow is analyzed in a three-dimensional basin.Taking into account the different working conditions when the water depth is 4m,8m and 12 m and the flow velocity is 2m/s,4m/s,6m/s and 8m/s respectively,the three-dimensional flow field analysis is carried out to obtain the pressure distribution of the pier surface.On this basis,the influence of flow velocity,water depth and boundary conditions on the dynamic response of bridge piers is investigated.The embedment depth of the pier was determined based on the actual measured values of the scouring depth.the influence of scour depth on the dynamic response of the pier is studied under the conditions of 0.5m/s,1m/s and 1.5m/s.