研究目的: 温度作为大跨斜拉桥上无缝线路产生纵向力的主要因素,其作用特征具有明显的时变特性,桥上无缝线路结构的受力与变形处于动态变化中。本文针对施工锁定至开通运营阶段结构温变特征,考虑线路纵向阻力滞回本构关系,建立千米级主跨斜拉桥上无缝线路空间耦合模型,分析不同温度加载历程下无缝线路力学特性与变形规律。
研究结论: (1)桥上无缝线路温度“加载-卸载-反向加载”过程中,线路纵向阻力会进入塑性状态,温度卸载后线路仍存在一定的纵向残余变形,钢轨内部存在残余附加力;(2)温度循环作用过程中,梁-轨残余变形在反向加载时可抵消部分梁-轨相对位移从而降低线路纵向阻力,温度卸载后钢轨和桥梁均会发生不可自动恢复的纵向残余变形;(3)与传统的单次全幅值加载相比,考虑温度循环历程、不设置调节器时,钢轨纵向力峰值可降低14.57%,梁-轨相对位移峰值增大46.28%;(4)设置调节器后,考虑温度循环加载历程,钢轨纵向力峰值降低11.4%,梁-轨相对位移峰值增大52.4%,但峰值相对较小;(5)本研究成果可为大跨斜拉桥上无缝线路设计与运维提供理论参考。

Research purposes: Temperature is the main factor of longitudinal force of CWR on long-span cable-stayed bridge. The action characteristics of temperature have obvious time-varying characteristics, the stress and deformation of CWR on the bridge is in dynamic change. According to the characteristics of structural temperature from construction locking to opening operation stage, considering the hysteretic constitutive relation of CWR longitudinal resistance, a spatial coupling finite element model of CWR on cable-stayed bridges with thousand-meter-scale main span is established, and the mechanical characteristics and deformation law of CWR under different temperature loading process are analyzed.
Research conclusions: (1) In the process of temperature "loading-unloading-reverse loading", the line longitudinal resistance enters the plastic state, and there is still residual longitudinal deformation after temperature unloading, and there is residual additional force inside the rail. (2) In the process of temperature cyclic loading, the residual deformation of beam-rail can offset part of the relative displacement of beam-rail under reverse loading, thereby reducing the longitudinal resistance of the line. The unrecoverable longitudinal residual deformation of rail and bridge occurs after temperature unloading. (3) Considering the temperature loading process, compared with the traditional single full amplitude loading, the peak value of rail longitudinal force can be reduced by 14.57 % without rail expansion joints (REJ) and that for beam-rail relative displacement can be increased by 46.28%. (4) After installing the REJ, the peak value of rail longitudinal force could be reduced by 11.4 %, and the beam-rail relative displacement peak value could be increased by 52.4 % with considering the temperature cyclic loading process, but the peak value is relatively small. (5) The research results can provide theoretical reference for the design and operation of CWR on long-span cable-stayed bridge.