三角拱桥集中锚固区受力分析与设计

Stress Analysis & Design of Centralized Anchorage Zone of Triangle Arch Bridge

异型三角形拱桥的吊索需集中锚固于拱顶,在有限空间中实现有效传力,故是工程设计的关键部位。以宁海下徐溪桥为例,针对三角形拱桥集中锚固的受力复杂特点,通过设计整体节点板构造实现集中锚固,解决有限空间的锚固难题。进行设计及受力分析,可知集中锚固的整体节点板与拱肋形成整体构件性能较好,保证索力有效传递,明确结构传力路径,降低施工难度。通过弹性力学解析法与有限元分析法研究集中锚固区的应力分布,结果表明:销孔处会出现应力集中,最大Von-Mises应力为211.5MPa,满足承载力要求;销孔处加焊垫板,有效降低局部最大应力;应力在锚固区的分散有效、均匀,构造设计合理可行,为三角拱桥锚固提供可参考解决方案。

The suspension cable of specialshaped triangular arch bridge should be anchored at the vault to achieve effective force transmission in limited space, so it is the key part of engineering design. Taking Xiaxuxi Bridge in Ninghai as an example, aiming at the complex stress characteristics of centralized anchorage of triangular arch bridge, centralized anchorage is realized by designing integral joint plate structure to solve the anchorage problem in limited space. Through the design & stress analysis, it can be seen that the performance of the integral joint plate & arch rib formed by centralized anchorage is better, the effective transmission of cable force is guaranteed, the transmission path of structural force is clear, and the construction difficulty is reduced. The stress distribution in the centralized anchorage zone is studied by elastic mechanics analysis & finite element analysis. The results show that the stress concentration occurs at the pinhole, and the maximum Von-Mises stress is 211.5 MPa, which meets the bearing capacity requirement;the welding pad at the pinhole can effectively reduce the local maximum stress;the stress distribution in the anchorage zone is effective & uniform, and the structure design is reasonable & feasible, which may provide solution for the anchorage of triangular arch bridge.