Stμdy On The Application Range Of Friction Pendμlμm Bearing In Railway Beam Bridge

The friction pendulum bearing is widely used in the seismic design of railway bridges due to its excellent working performance.At present,there are many seismic isolation designs for individual projects of railway bridges,and there is a lack of detailed statistical analysis of multiple samples.Through the statistical analysis of railway bridges under different seismic design parameter combinations,it is necessary to clarify the application scope of seismic isolation design of railway bridges.In this paper,the 4×32 m typical span simply supported box girder bridge of high-speed railway and the(60+100+60)m prestressed concrete continuous girder bridge of high-speed railway are taken as the seismic analysis objects.The finite element analysis software Midas /civil is used to establish the analysis model.Considering the seismic design conditions of different spans,peak ground acceleration(PGA),friction pendulum bearing parameters,pier height and section form,the damping effect of friction pendulum bearing is adopted.The main research contents are:(1)Taking the four-span 24 m,32m and 40 m typical span high-speed railway simply supported beam bridge as the research object,the finite element software is used to establish the traditional seismic system and seismic isolation system model for nonlinear dynamic time history analysis.The influence of bridge pier height,bridge span,bearing parameters(u,R)and peak ground acceleration(PGA)on the seismic response of railway simply supported beam bridge is studied.(2)Taking the high-speed railway(60+100+60)m prestressed concrete continuous girder bridge as the research object,the finite element software is used to establish the traditional seismic system and the seismic isolation system model for nonlinear dynamic time-history analysis.The influence of bridge pier height,bearing parameters(u,R),peak ground acceleration(PGA)and transverse bridge block,block type,initial gap and other factors on the seismic response of railway continuous girder bridge and the damping effect are studied.(3)For24m,32 m and40m span high-speed railway simply supported beam bridge FPB bearing curvature radius R take 1.5～2.5m,equal section entity pier 5～20m,friction coefficient u take 0.03～0.05,variable cross-section hollow pier 25～45m,friction coefficient u take0.05～0.08,can make the FPB railway simply supported beam bridge to achieve the optimal isolation effect,meet the allowable bearing displacement 200 mm(PGA=0.38g).(4)For the high-speed railway continuous beam bridge with a main span of 100 m,the curvature radius R of the FPB bearing is 4～6m,the equal-section solid pier is within 20 m,and the friction coefficient u is 0.04～0.06,which can make the FPB railway continuous beam bridge have the best damping effect and the bearing displacement meet the design displacement requirements(PGA=0.38g).(5)The impact stiffness(block type)has a significant effect on the internal force of the pier bottom.The 40 m pier height has a better damping effect using hardwood block.The 10 m pier height can be based on the actual engineering situation.The damping rate of the 40 m pier height is above 41 %.The FPB + steel block system still has a good damping effect.