大跨度梁拱组合桥的梁轨相互作用设计参数研究

Study of Design Parameters of Beam-Track Interaction of Long Span Hybrid Bridge of Beam and Arch

为了解梁轨相互作用设计参数对大跨度梁拱组合桥无缝线路的影响,以兰渝线广元段某(82.9+172+82.9)m梁拱组合桥为例,采用ANSYS软件建立了考虑拱肋-吊杆-主梁-桥墩-桩基-轨道梁轨系统一体化有限元模型,分析了拱肋与吊杆升温、纵向阻力模型、吊杆间距、桥墩高度、制动力率、风荷载等参数对钢轨纵向力的传递规律。结果表明:拱肋升温对钢轨应力的影响较大,计算钢轨伸缩力时,按梁体升温15℃考虑较为安全;梁拱组合桥的梁轨相互作用根据《铁路无缝线路设计规范》计算较为安全;钢轨制动力随固定墩高度的增加而增大,固定墩的墩顶水平力与其墩高基本呈线性递减关系;钢轨应力随吊杆间距的增大而增加;钢轨的最大制动拉、压应力和固定墩的墩顶水平力均与制动力率呈线性关系;风荷载作用下,钢轨应力可达5.8 MPa以上,风速较大区域需考虑风荷载对钢轨的影响。

To understand the effect of the design parameters of beam-track interaction on the continuously welded rail on long span hybrid bridge of beam and arch, a hybrid bridge of beam and arch with span arrangement （82. 9＋172 ＋ 82. 9） m on the Guangyuan section of Lanzhou- Chongqing Railway was taken as an example, a finite element model considering the integration of the arch rib--hangers--main beam--piers--pile foundations--beam-track system was established, using the software ANSYS and the effect of the design parameters, such as the temperature rise in the arch rib and hangers, longitudinal resistance models, hanger spacings, pier height, braking force ratios and wind load, on the longitudinal force transmission laws of the steel rail was analyzed. The results of the analysis show that the effect of the temperature rise in the arch rib on the steel rail stress is great and when the steel rail expansion force is calculated, the calculation according to the temperature rise of 15 ℃ in the beam is safe. When the beam-track interaction of the hybrid bridge is calculated, the calculation of the interaction according to the Code for Design of Railway Continuous Welded Rail is safe. The braking force of the steel rail increases with the in- crease of the fixed pier height and the pier top horizontal force of the fixed pier basically exhibits the linear decrease relationship with the height of the fixed pier. The steel rail stress increases with the increase of the hanger spacings. The maximum braking tensile and compressive stress of the steel rail and the pier top horizontal force of the fixed pier all exhibit the linear relationship with the braking force ratios. Under the action of the wind load, the steel rail stress can be greater than 5.8 MPa and in the area of fast wind speed, the effect of the wind load on the steel rail should be considered.