采用非线性弹簧模拟无缝线路纵向阻力，用带刚臂的梁单元模拟梁体，以黄韩侯铁路线上某 156m 简支钢桁梁桥为例，分析相邻桥跨结构对大跨度简支钢桁梁桥上无缝线路纵向力分布规律的影响，提出相关参数的取值建议． 研究表明:分析大跨简支钢桁梁桥上无缝线路纵向力时，两侧的多跨简支梁在下部结构纵向刚度相差较小的情况下可按6 跨进行简化;与 32 m 标准跨度相比，相邻简支梁跨度为 24 m 时固定端伸缩力降低了9%，40m 时固定端伸缩力增大了 7%;相邻桥跨为大跨连续梁时，钢桁梁固定端伸缩力增大了2． 2 倍，全桥伸缩压应力最大值增大了12%;在连续梁与钢桁梁之间布置1 跨或2 跨简支梁可大幅降低钢桁梁固定端的钢轨应力;在钢桁梁桥上设置小阻力扣件可使伸缩工况下钢桁梁的钢轨应力最大值和桥墩水平力显著减小．

By taking a 156m large-span simply-supported steel truss girder on the Huangling-Hancheng-Houma line as a case,the influence of adjacent bridges on the longitudinal force distribution in the continuously-welded rail (CWR) on the steel truss girder is analyzed,and some suggestions are presented for the selection of relevant pa- rameters.In the investigation,nonlinear spring is used to simulate the longitudinal resistance of CWR and the beam element with rigid arms is employed to simulate the steel truss bridge.Calculation results show that (1) when the longitudinal stiffness of the substructure has no obvious variation,the multi-span simply-supported beams at both sides of the steel truss girder can be simplified into a girder with 6 spans for analyzing the longitudinal force; (2) as compared with the standard span of 32m for simply-supported beams,a span of 24 m may result in a force de- crease at the fixed end by 9%,while a span of 40m may result in a force increase by 7%; (3) by taking the adja- cent large-span continuous beam into consideration,the longitudinal force at the fixed end of the steel truss girder increases by 2. 2 times and the maximum compressive stress of the full bridge increases by 12%; (4) the longitudi- nal force at the fixed end of the steel truss girder is significantly reduced when simply-supported beams with one or two spans are arranged between the continuous beam and the steel truss girder; and (5) fasteners with small resis- tance helps to reduce the maximum stress and the horizontal force loaded on the pier.