Effect Of Friction Pendulum Bearing On Vehicle Running Safety On Bridges Shaken By Earthquakes

With the rapid development of high-speed rail,the proportion of bridges along the high-speed railway is increasing.More and more high-speed rail lines directly cross earthquake-prone areas.The interaction of the vehicle-bridge system under earthquake has gradually attracted the attention of scholars.Scholars have successively proposed detailed earthquake-vehicle-bridge-dynamic analysis models to evaluate the running safety of vehicles passing through bridges during earthquakes,but there are still some unresolved problems: Most existing earthquake-vehicle-bridge models treat bridges as linear structures without considering the effects of bridge nonlinearity on the coupling system;In high-intensity areas,friction pendulum isolation bearings are often used to reduce bridge damage,but the impact of friction pendulum bearings on running safety is not yet clear.The research content of this thesis includes:(1)Currently,there is no commercial software for earthquake-vehicle-trackbridge nonlinear analysis.In this thesis,the existing vehicle-track-bridge analysis theory was used to develop the earthquake-vehicle-track-bridge nonlinear analysis software.The software supports wheel-rail nonlinear contact calculation and wheel-rail separation.At the same time,Open Sees was encapsulated and the corresponding interface was developed to enable it to be better used for vehicle-bridge analysis.The use of multi-time step explicit-implicit integrated algorithm improves the calculation efficiency of the vehicle-rail-bridge dynamic system.The validity of the software was verified using a commercial finite element program.(2)In this thesis,the nonlinear-vehicle-rail-bridge calculation program was used to calculate the dynamic response of a train passing through a 50-span simply supported beam bridge with friction pendulum bearings,and the same simply supported beam bridge with common bearings was used for comparison.The impact of friction pendulum bearings on the running safety of high-speed trains was analyzed.The results show that the friction pendulum bearings can significantly reduce the acceleration of the vehicles on the bridge,the relative displacement of the wheel and rail and the lateral force of the wheel and rail are significantly reduced.Friction pendulum bearings are beneficial to improve the safety of vehicles on bridges under earthquake conditions.(3)In actual engineering,the timing of the sliding of the friction pendulum bearing cannot be exactly the same,and the sliding inconsistency occurs after the sliding.All of the above reasons can lead to lateral misalignment between the girders of the two spans adjacent to the Bridge,thus affecting the safety of high-speed trains when passing through the bridge.In this thesis,the simplified model and numerical calculation program were used to study the influence of the shear strength of the anti-slip bolt,friction coefficient and rail constraint on lateral misalignment and the distribution of stagger under different conditions.Finally,the dynamic response of a high-speed train through a 50-span simply supported beam bridge with friction pendulum bearing(under consideration of staggering)during earthquakes was studied.The results show that staggering has a huge impact on driving safety,and can significantly increase derailment indicators such as wheel-rail lateral force,wheel-rail lift and wheel-rail lateral displacement.