大跨度轨道桥梁在地震及列车倚载作用下的动力响应分析

为探讨实用的轨道桥梁抗震设计方法，通过建立地震荷载作用下车-轨-桥系统的动力响应分析模型，以跨越长江的武汉天兴洲公铁两用斜拉桥为研究对象，运用计算机仿真的方法，模拟了列车在不同强度和频率正弦波作用下过桥的全过程。分析了车辆类型、地震强度和频谱特征等因素对地震发生时车辆与桥梁结构动力响应的影响，以脱轨系数、轮重减载率和横向轮轨力作为评价标准，给出了确保地震发生时列车安全运行的桥梁容许横向位移限值和横向加速度限值，可供轨道桥梁抗震设计时参考。

Dynamic Response Analysis on Long-Span Bridges under Earthquake and Train Loads

Through the establishment of response analysis model for train-track-bridge system under seismic loads, the paper takes the Yangtze River Wuhan Tianxingzhou rail-highway cable-stayed bridge as research case, using computer simulation method to simulate entire process of train at different intensity and frequency sine wave effect across bridge. It makes an analysis on vehicle type, intensity and spectrum characteristics of earthquake and other factors, the impact to vehicle and dynamic response of bridge structural when earthquake occurs. Taking the deraihnent coeMcient, wheel load reduction rate and lateral wheel- rail forces as the evaluation criteria, the paper gives the bridge allowable lateral displacement limit and lateral acceleration limit to ensure train sate operation on bridge when earthquake occurs.