大跨度钢桁斜拉桥上无缝线路制动力的计算

摘要

为探讨大跨度钢桁斜拉桥上无缝线路制动力的传力机制,基于有限元法和梁轨相互作用理论,建立了反映斜拉索、主塔、半漂浮体系等桥梁特征的梁轨纵向相互作用平面模型,分析了斜拉索刚度、主塔刚度以及半漂浮体系中粘滞阻尼器对制动力的影响,并提出了制动力的简化算法.研究结果表明:制动力满足斜拉桥上铺设无缝线路的要求,且其分布规律与普通桥上相同；粘滞阻尼器对制动荷载下斜拉桥上无缝线路梁轨相互作用的改善较明显,有效降低了梁轨相对位移,减小了制动力；与主塔刚度相比,斜拉索刚度对桥上无缝线路制动力的影响较大,因此,设计桥上无缝线路时,可只考虑斜拉索刚度的影响.%In order to probe into the transmission mechanism of braking force on continuous welded rail (CWR) on a large-span steel truss cable-stayed bridge, a plane model for bridge-rail interaction was established based on the finite element method and the bridge-rail interaction theory. In this model, all structural characteristics, such as steel truss, stay cables, main towers, and viscous dampers, are involved. The influences of stay cable stiffness, main tower stiffness and viscous dampers on the braking force were analyzed, and a simplified algorithm for the braking force was proposed. The results show that braking force can meet the demands of paving CWR on cable-stayed bridges, and its distribution regularity is the same as that on conventional bridges; viscous dampers improve the bridge-rail interaction in train braking situation by reducing bridge-rail relative displacement and braking force; compared with the stiffness of main towers, the stiffness of stay cables has a great influence on the braking force, so it should be taken into account in CWR design of a cable-stayed bridge.