异形岔道梁桥有限元分析与抗倾覆研究

Finite Element Analysis and Anti-overturning Research of Special-shaped Turnout-beam Bridge

摘要:

为保证带外伸横梁的异形岔道梁桥抗倾覆稳定性，结合某工程实例综合采用了设置外伸横梁等4项构造措施。采用Midas Civil 2021建立了全桥梁格模型与全桥板单元模型并进行分析对比，分析了桥跨结构的倾覆破坏机理，提出了实用抗倾覆计算方法。研究表明：梁格法对此类桥梁的计算精度可以满足工程应用的要求；外伸横梁与B岔道根部弯曲破坏失效是桥梁倾覆的最终阶段和前提条件；外伸横梁越短，提供的抗倾覆力矩越大。本次设计采用的4项构造措施均可有效提高结构抗倾覆稳定性，安全系数为10.1，大于2.5，满足规范要求，可为同类桥梁抗倾覆优化设计（如减小外伸横梁根数、调整外伸横梁结构尺寸等）提供依据和参考。

Abstract:

In order to ensure anti-overturning stability of the special-shaped turnout-beam bridge with overhanging beams, and combined with an engineering example, four structural measures such as setting overhanging beams are adopted. Midas Civil 2021 is used to establish the full bridge grillage model and the full bridge plate element model, and the models are analyzed and compared. The overturning failure mechanism of the span structure is analyzed. And the practical anti-overturning calculation method is proposed. The study results show that the calculation accuracy of grillage method for this kind of bridge can meet the requirements of engineering application. The bending failure of the overhanging beam and B turnout root is the final stage and prerequisite of bridge overturning. The shorter the overhanging beam, the greater the anti-overturning moment provided. All four structural measures adopted in this design can effectively improve the anti-overturning stability of structure. The safety factor is 10.1, larger than 2.5, which meets the specifications. The basis and reference can be provided for the anti-overturning optimization design of the similar bridges (i.e. reducing the number of overhanging beams and adjusting the structural size of overhanging beams).