Analysis Of Friction-slip Characteristics Of Pot Bearings In Continuous Curved Girder Bridges

The concrete curved girder bridge is complicated in force,and the lateral deviation of the main beam often occurs.The lateral deviation of the main beam can result in the shear deformation,the void,the displacement overrun of the support.As the support is used as the connecting component of the superstructures and substructures,its mechanical properties will also affect the lateral displacement and internal force response of the structure.There are many research results in the academic field on the lateral deviation of curved bridges,but little attention is paid to the influence of bearing performance on the structure.The main purpose of this paper is to investigate the effect of the frictional slip effect of the bearing on the lateral response of the concrete curved girder bridge,and to determine whether the frictional slip effect of the basin bearing needs to be considered in the conventional bridge design.At the same time,the results of the study will provide solutions for the maintenance and reinforcement of bridges that have suffered from such diseases.To this end,this paper mainly carried out the following works.(1)Firstly,based on the investigation results of domestic and foreign literatures,the research status of transverse displacement of concrete curved girder bridges and frictional slip characteristics of pot rubber bearings are introduced.Meanwhile,the purpose and significance of this study are put forward.(2)The three-dimensional solid model of GPZ(2009)2.5SX±50mm pot rubber bearing was established by ANSYS,mainly considering the contact nonlinearity of the bearing contact surface and the nonlinearity of the rubber material.Based on this model,the stress and deformation of the PTFE plate,the pot ring,the three-way compression rubber block and the support base plate of the basin rubber bearing were carefully analyzed.The calculation results show that the basin rubber bearing has stable mechanical properties,and the maximum principal stress,vertical compression deformation and radial deformation of the bearing under the vertical load design meet the design requirements.(3)The finite element simulation bearing vertical bearing capacity test is used to compare the load displacement curve with the bearing capacity test results of the 2.5MN pot rubber bearing completed by the Highway Research Institute of the Ministry of Transport.The comparison results show that the maximum error between the calculated value of the finite element and the experimental value of the vertical compression deformation is 4.8%,which verifies the accuracy of the finite element model.(4)Based on the above finite element model,the frictional slip characteristics of the bearing under one-way horizontal loading are further simulated.The loading is controlled by displacement.The single-load loading constant-amplitude cyclic loading,variable-amplitude cyclic loading,harmonic displacement loading and other conditions are analyzed.Block load displacement curve.The calculation results show that the basin rubber bearing forms a full hysteresis curve with a rectangular shape,indicating that the basin bearing has a certain energy consumption capacity.(5)Two concrete curved beam bridge models are established.The model 1 does not consider the friction and slip characteristics of the bearing,and simulates the bearing through the joint coupling.The model 2 considers the friction and slip characteristics of the bearing and simulates the bearing through the nonlinear spring unit.Then,the time-history analysis method is used to calculate the influence of the friction and slip characteristics of the bearing on the lateral displacement and internal force of the concrete curved bridge.The calculation results show that considering the friction and slip characteristics of the basin support can effectively reduce the seismic response of the structure.If the frictional slip of the bearing is considered,the friction coefficient should be reasonably selected.If the friction coefficient is too large,the calculation result will be unsafe.