Study On The Isolation Performance Of New Type Pouring Bearing

In recent years,large-span bridges have been constructed on a large scale,which puts higher requirements on the vertical bearing capacity of bridge isolation bearings,while the vertical bearing capacity of traditional isolation bearings is relatively insufficient.The new type pouring bearing adopts new polymer material,which makes it have a large vertical bearing capacity and good damping performance.The energy analysis method can be used to quantitatively calculate the energy input,transformation and dissipation at any time of the structure,which can be used to evaluate the isolation performance of the seismic isolation device from a new perspective.However,there are still few applications in the analysis of the isolation performance of bridge bearing.Based on the existing research,this paper studied the isolation performance of the new type pouring bearing by using the methods of dynamic time history analysis and energy analysis.In this paper,the mechanical properties of the new type pouring bearing were studied.The simplified mechanical model of the bearing and the basic parameter fitting method were introduced.Through the cyclic shear test of the bearing,the basic mechanical properties,shear strain correlation and compressive stress correlation of the new type pouring bearing were studied.The model theory formula was used to fit the test curve,which provided the calculation basis for the selection of the support parameters in the later analysis.Then a 30 m span continuous girder bridge model based on the actual engineering was established by Midas.The dynamic characteristics and seismic response of the new type pouring bearing system were obtained by calculation.The results show that the highcapacity isolation bearing has a good ability to control the displacement and internal force of the bridge under earthquake.An energy analysis method calculation formula based on the calculation result of the finite element software was proposed.This method can quantitatively calculate the seismic input energy of the isolated system,the hysteretic energy of the bearing,and the damping energy dissipation.And the method was applied to other analysis of this paper.Finally,in order to study the influence of natural vibration period(span)and site type on the isolation performance of the new type pouring bearing,seismic time-history analysis was carried out for different span-continuous beam bridges and 40m-span continuous beam bridges of different site types.The results show that the isolation performance of the new type pouring bearing was better under the low natural vibration period and soft soil foundation.