一座大跨弧形变高度钢桁架人行天桥设计研究

Design and Research of Large-span Curved Variable Height Steel Truss Pedestrian Overpass

摘要:

以某大跨弧形变高度钢桁架人行天桥为设计背景，通过建立空间有限元模型，与取消竖杆后的钢桁架、等高度钢桁架和钢管桁架进行对比分析，得出：当节间距较小时，竖杆对整体竖向刚度的影响小于对整体结构质量的影响，取消竖向后可以增加结构的固有频率；弧形钢桁架会导致整体竖向刚度下降，常规条件下宜选用等高度桁架形式，可降低桁架高度，节约用钢量；钢管桁架能更好地发挥材料特性，较箱形桁架能较大地发挥截面特性，能减少用钢量和焊接工作量。研究结果可为今后同类人行天桥提供一定的借鉴和参考意义。

Abstract:

Taking a large-span curved variable height steel truss pedestrian bridge as the design background, a spatial finite element model is established to compare and analyze the steel truss, equal height steel truss and steel pipe truss after the removal of vertical bars. The conclusion is that when the spacing between sections is small, the impact of vertical bars on the overall vertical stiffness is less than that on the overall structural quality, and the removal of vertical bars can increase the natural frequency of the structure. The arc-shaped steel truss can lead to a decrease in overall vertical stiffness. Under the conventional conditions, the equal height trusses should be selected to reduce the height of the truss and save the steel consumption. The steel pipe truss can better play the material characteristics and play the larger cross-sectional characteristics than the box truss, which can reduce the steel consumption and welding workload. The research results can provide some reference for similar pedestrian overpasses in the future.