偏载工况下多线大跨系杆拱连续梁桥梁轨相互作用
Interaction between tied arch continuous bridge and multiple tracks in unbalance load cases

为研究偏载工况对大跨度桥梁与多线轨道相互作用的影响，以某4线(77+3×156.8+77) m钢管混凝土系杆拱-预应力混凝土连续梁组合结构桥梁为例，采用带有刚臂的梁单元模拟主梁，用带组合截面信息的梁单元模拟钢管混凝土拱肋，用非线性杆单元模拟线路纵向阻力，建立可考虑吊杆、支座和轨道空间位置，以及钢轨伸缩调节器影响的大跨度系杆拱连续梁桥与多线轨道相互作用空间分析模型。在此基础上，研究多线活载(挠曲和制动)偏载工况下，钢轨纵向力的分布情况，以及墩顶所受水平力和扭矩。研究结果表明：由于主梁刚度较大，有载与无载线路间相互影响较小；竖向活载作用下，有载和无载线路挠曲力相仿；重载线路侧双线列车逆向制动时，在本桥墩顶产生的扭矩可超过8 000 kN？m，在墩台设计时应予以考虑。
To study the impact of unbalance load cases on interaction between long-span bridge and multiple tracks, a composite bridge with both (77+3×156.8+77) m concrete filled steel tube tied arch and prestressed concrete continuous beam was taken as an example. The beam element with rigid arm was used to simulate the prestressed concrete girder, beam elements with composite sections were used to simulate concrete filled steel tube arch and nonlinear bar element was used to simulate the track resistance. Spatial analysis model for the interaction between the large span continuous bridge with tied arch and multiple tracks was established. The suspender, bearing and track space locations, as well as the impact of rail expansion device were considered. On this basis, the distribution of track longitudinal force, as well as the horizontal force and torque applied to the pier top, was studied in the unbalance loaded case of multiple-track live loads (bending and braking). Research shows that, the interaction between loaded track and unloaded track was smaller due to the larger girder stiffness; under vertical live loads, the bending forces of both loaded and unloaded tracks are similar; when double-track train brakes reversely on one side of heavy load track, the torque generated on the pier top can be more than 8 000 kN？m, which should be considered in the design of piers