宽幅异形钢板组合梁的设计与研究

以丰台火车站东侧立交专用匝道宽幅异形钢板组合梁桥为研究对象，从结构优化和安全设计两方面对组合梁桥进行分析，以桥梁结构安全性与经济性为原则，提出最优设计方案。在有限元软件中，采取刚臂连接模拟剪力钉设置，结合混凝土桥面板和工字形钢主梁，建立全桥整体模型；通过调整中横梁设置个数、改变支座平面布置方式，优化桥梁结构设计；根据桥梁实际受力情况，分析桥梁结构在常态下钢主梁的刚度、承载能力、屈曲稳定和疲劳应力情况。结果表明：在满足结构使用安全的情况下，减少中横梁数量，会增加结构应力，降低稳定安全系数；宽幅异形钢板组合梁受混凝土收缩影响明显，外侧支座容易脱空，优化支座布置显得尤为重要；在正常使用状态下，钢板组合梁外侧主梁刚度较小，变形明显，应力较大，最早容易出现屈曲失稳，且受疲劳荷载影响较为敏感。

Design and Research of Wide Special-shaped Steel Plate Composite Beam

Taking the wide special-shaped steel plate composite beam bridge for the special ramp of interchange at the east side of Fengtai Railway Station as the research object, the composite girder bridge is analyzed from the aspects of structural optimization and safety design. Based on the principle of structure safety and economy of the bridge, the optimal design scheme is proposed. In the finite element software, the rigid arm connection is used to simulate the setting of shear nails. Combined with the concrete bridge deck and the I-shaped steel girder, the overall model of the whole bridge is established. By adjusting the number of middle beams and changing the plane layout of the supports, the bridge structure design is optimized. The stiffness, bearing capacity, buckling stability and fatigue stress of the steel girder of the bridge structure under the normal conditions are analyzed according to the actual stress of the bridge. The results show that reducing the number of middle beams will increase the structural stress and reduce the stability safety factor under the condition to satisfy the safety of the structure. The wide special-shaped steel plate composite beam is obviously affected by the shrinkage of the concrete, and the outer support is easy to be emptied. It is particularly important to optimize the support layout. Under the normal service condition, the outside girder of steel plate composite girder has the small stiffness, obvious deformation and large stress, and is prone to buckling instability at the earliest, and is sensitive to fatigue load.