In order to evaluate the effect of seismic isolation on random seismic response characteristics of a track-bridge system, in this paper, a three-dimensional detailed nonlinear dynamic model consists of rail, CRTS II slab ballastless track, high-speed railway simple supported bridges, isolated bearings, piers, pile foundations from top to bottom, is established by OpenSEES. The stochastic process of ground motion constructed by the random harmonic function is taking as random excitation, and the probability density evolution method (PDEM) is applied to investigate and analyze the system from the random perspective. On this basis, the influence of FPB bearing and the different FPB parameters (such as equivalent radius) on the random seismic response of the track-bridge system is studied. Thereby, aplenty probabilistic information (probability density evolution function, mean value and standard deviation) can be gained of seismic response of isolated bridges with different isolation parameters and non-isolated bridges of the high-speed railway track-bridge system under the excitation of random earthquakes by case study. Through the comparison of random seismic responses of non-isolated bridge and isolated bridges with different parameters under random ground motions, the favorable and unfavorable effects of seismic isolation for high-speed railway bridges are explored and demonstrated from a random point of view. The comparison of the random seismic response under different cases are discussed and significant outcomes are drawn. Results show that: The use of isolation bearing can reduce the response of track structure and pier, but meanwhile, increase the response of bearings. The change of the equivalent radius of the isolation bearing has no obvious influence on the random response of the pier and the track structure, but will to some extent bring the change of the bearing response. The results can be used for the seismic design and maintenance of the railway high-speed bridge.

为了评估隔震对轨道桥梁系统随机地震响应特征的影响，本文建立了三维详细的非线性动力学模型，该模型由轨道，CRTS II平板无ball轨道，高速铁路简支桥梁组成OpenSEES建立了从上到下的隔离式轴承，墩，桩基。以随机谐波函数构造的地震动随机过程为随机激励，采用概率密度演化法（PDEM）从随机的角度对系统进行研究和分析。在此基础上，研究了FPB轴承和不同FPB参数（如等效半径）对轨道桥系统随机地震响应的影响。从而，通过随机地震的激励，可以得到高速铁路轨道桥系统中具有不同隔离参数的隔离桥和非隔离桥的地震响应的大量概率信息（概率密度演化函数，均值和标准差）。案例分析。通过比较随机地震作用下非隔离桥梁和具有不同参数的隔离桥梁的随机地震反应，从随机的角度探讨和证明了高速铁路桥梁隔震的有利和不利影响。讨论了不同情况下随机地震响应的比较，并得出了重要的结果。结果表明：采用隔震支座可以减少轨道结构和墩墩的响应，但与此同时，增加轴承的响应。隔震支座等效半径的变化对墩墩和轨道结构的随机响应没有明显影响，但会在一定程度上带来支座响应的变化。研究结果可用于铁路高速桥梁的抗震设计和维护。