Research On Seismic Isolation Performance Of High-Speed Railway Bridge Based On Shaking Table Test

Because of its comfort,rapidity,environmental protection and safety,high-speed railway will gradually become the main mode of transportation people choose to travel.In order to save land and reduce energy consumption,bridges usually occupy a large proportion in high-speed railway lines.As an important part of high-speed railway system,the damage of high-speed railway bridge in earthquake will cause serious consequences.The piers of high-speed railway bridge must have enough rigidity to ensure the stability of the bridge.Under earthquake action,the structure with large stiffness is subjected to more earthquake,and it is easier to damage the bridge structure.Therefore,it is necessary to study the isolation technology of the bridge structure of high-speed railway.At present,domestic and foreign scholars studied the earthquake disaster and isolation technology of high-speed railway isolated bridges through theoretical research,and there are few research results about the shaking table test of the high-speed railway bridge.In this paper,the vibration isolation performance of high speed isolated bridges is studied by the method of combining shaking table test with numerical simulation.The main research work of this paper includes the following aspects:(1)The double concave friction pendulum isolation bearings is designed and manufactured to meet the needs of shaking table test of high speed isolated bridges.The mechanical properties of the double concave friction pendulum bearing are tested,and the theoretical calculation results are compared with the experimental results.It is found that the theoretical calculation is consistent with the result of low cyclic loading test,that is,the horizontal force-displacement constitutive relationship of the double concave friction pendulum bearing can be effectively simulated by using the double-fold hysteretic model.(2)Taking a span standard of 32.5 meters simply supported bridge of an actual high-speed railway in China as the research object,designed and made a model of isolated bridge of high-speed railway with a scale ratio of 1:13.El-Centro wave,Wenchuan wave and San Francisco wave are used as input ground motions.The double concave friction pendulum of isolation bearings is applied to the high-speed railway bridge,and the seismic simulation shaking table test is carried out on the model of isolated bridge of high-speed railway.The response of shaking table test of model structure under the action of different seismic fortification intensity was measured in the test.It includes the acceleration and displacement of the beam and the top of the pier,the shear deformation of the friction pendulum bearing,the strain of the steel and concrete at the bottom of the pier.The test results show that the double concave friction pendulum bearing can effectively consume the energy of ground motion and reduce the dynamic response of the bridge.And when the earthquake intensity is increased,the shock absorption effect of the isolated bridge model is better.(3)The isolated bridge model of high-speed railway for shaking table test is established by using the OpenSees finite element software.The table acceleration record of shaking table is selected as the input ground motion of finite element analysis,and the dynamic time history response analysis is carried out.The results of the finite element analysis and the shaking table test are compared,and the accuracy of the test results is verified.(4)According to the working principle of the double concave friction pendulum of isolation bearings and the electromagnetic induction,the electromagnetic damping and the double concave friction pendulum of isolation bearings are combined.A new type of electromagnetic damping friction pendulum bearing is designed and produced.The theoretical analysis of the new electromagnetic damping friction pendulum bearing is carried out,and the electromagnetic damping force of the bearing is deduced.(5)The electromagnetic damping friction pendulum bearing was applied to the shaking table test model of high-speed railway bridge.And the shaking table tests were carried out on the high-speed railway bridge with electromagnetic damping friction pendulum bearing and double concave friction pendulum bearing respectively.At last the test results are compared to verify the isolation performance of electromagnetic damping friction pendulum bearing.