To explore the influence of spatially varying ground motion on the dynamic behavior of a train passing through a three-tower cable-stayed bridge, a 3D train–track–bridge coupled model is established for accurately simulating the train–bridge interaction under earthquake excitation, which is made up of a vehicle model built by multi-body dynamics, a track–bridge finite element model, and a 3D rolling wheel–rail contact model. A conditional simulation method, which takes into consideration the wave passage effect, incoherence effect, and site-response effect, is adopted to simulate the spatially varying ground motion under different soil conditions. The multi-time-step method previously proposed by the authors is also adopted to improve computational efficiency. The dynamic responses of the train running on a three-tower cable-stayed bridge are calculated with differing earthquake excitations and train speeds. The results indicate that (1) the earthquake excitation significantly increases the responses of the train–bridge system, but at a design speed, all the running safety indices meet the code requirements; (2) the incoherence and site-response effects should also be considered in the seismic analysis for long-span bridges though there is no fixed pattern for determining their influences; (3) different train speeds that vary the vibration characteristics of the train–bridge system affect the vibration frequencies of the car body and bridge.

中文翻译：

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空间变化地面运动下横穿三塔斜拉桥的列车运行安全性评估

为了探讨空间变化的地面运动对经过三塔斜拉桥的列车动力行为的影响，建立了3D列车-轨道-桥梁耦合模型，以精确模拟地震激励下的列车-桥梁相互作用，它由多体动力学建立的车辆模型，轨桥有限元模型和3D滚轮-钢轨接触模型组成。采用一种条件模拟方法，该方法考虑了波通过效应，非相干效应和位点响应效应，以模拟不同土壤条件下空间变化的地面运动。还采用了作者先前提出的多时间步方法来提高计算效率。在不同的地震激励和列车速度下，计算了在三塔斜拉桥上运行的列车的动力响应。结果表明：（1）地震激励显着提高了列车－桥梁系统的响应，但在设计速度下，所有运行安全指标均符合规范要求；（2）大跨度桥梁的地震分析也应考虑不连贯性和场地响应效应，尽管没有确定影响力的固定模式；（3）不同的火车速度会改变火车-桥梁系统的振动特性，从而影响车身和桥梁的振动频率。结果表明：（1）地震激励显着提高了列车－桥梁系统的响应，但在设计速度下，所有运行安全指标均符合规范要求；（2）大跨度桥梁的地震分析中也应考虑不连贯性和场地响应效应，尽管没有确定确定其影响的固定方式；（3）不同的火车速度会改变火车-桥梁系统的振动特性，从而影响车身和桥梁的振动频率。结果表明：（1）地震激励显着提高了列车－桥梁系统的响应，但在设计速度下，所有运行安全指标均符合规范要求；（2）大跨度桥梁的地震分析中也应考虑不连贯性和场地响应效应，尽管没有确定确定其影响的固定方式；（3）不同的火车速度会改变火车-桥梁系统的振动特性，从而影响车身和桥梁的振动频率。