Analysis Of Shock Absorption Performance Of Triple Friction Pendulum System Applied To Small Radius Curved Beam Bridge

In the road traffic of our country,the application of small-radius curved girder bridges is more and more extensive,however due to the unique structural characteristics of the bridges,the damage is more serious under the action of earthquakes.Therefore,it has great significance for the seismic response and the study of the earthquake isolation of the curved girder bridges.In this paper,the fourth joint of the A bridge in the viaduct of Huangshui Road(Chaidamu Road-Kunlun Avenue)in Xining City is used as the engineering background to study the seismic isolation effect of the application of triple friction pendulum support and high damping rubber bearing in the curved girder bridge.The research work in this paper includes the following aspects:(1)Combined with relevant literatures,the main forms of the bridge seismic damage and the research status of curved beam bridge and triple friction pendulum support are summarized.This paper introduces the basic structure,working mechanism,force and displacement relationship of the triple friction pendulum bearing and the simulation method of the bearing unit in Midas/Civil finite element software and the calculation method of the related parameters in detail.(2)Based on the actual engineering background,a finite element model of a small radius curved beam bridge is established by using Midas/Civil finite element software,and the self-vibration characteristics of the bridge are analyzed.(3)It selects the line of A9 and A12 bridge piers as the 0° direction,and defines this direction as the X direction and the direction which perpendicular to the X direction as the Y direction.The two orthogonal directions simultaneously increase 20°,40°,60°,80°,100°,120°,140° and 160° in the counterclockwise direction,counting up to nine input directions.It inputs three seismic waves(El-Centro wave,San Fernando wave and Taft wave)in the calculation model according to the above nine input directions for time-history analysis,and the pier bottom shear force,pier bottom bending moment and main beam displacement of the A11 pier are established as the response parameters.The response parameters are used to compare and analyze the seismic response difference of each seismic wave input angle and the influence of different seismic waves on the most unfavorable seismic input angle of the bridge,and finally determine the most unfavorable ground motion input direction of the bridge.(4)The peak accelerations of the three seismic waves are sequentially adjusted to 0.1g,0.2g,0.3g,0.4g and 0.5g,and the most unfavorable ground motion input direction determined above is used as the ground motion input direction of the part of the research to study theseismic response of the bridge which is set the triple friction pendulum bearing and the high damping rubber bearing separately.It compares the seismic isolation effects of the two isolation devices on the curved beam bridge under different seismic waves and different peak accelerations by the seismic isolation parameters consisting of the fixed pier bottom shear,moment,torque,the fixed pier top displacement and the main beam displacement.And the shock absorption rate is used as an evaluation index to comprehensively evaluate the isolation performance of the two bearings.