铁道建筑

本文以某上跨高速公路的铁路曲线矮塔斜拉桥为研究对象，基于有限元分析方法，揭示了曲线效应对结构受力特性的影响，提出了合理设计对策。研究表明，曲线段主墩支座因离心力效应存在显著反力差异，通过优化支座布置方案可有效协调内外侧受力，降低墩顶弯矩对下部结构的不利影响。曲线段因斜拉索空间效应形成桥塔弯矩的非对称分布，需针对性在桥塔横梁中配置预应力钢束以平衡空间效应带来的影响，确保桥塔结构安全。同时，曲线效应对主梁扭矩及横向弯矩具有放大效应，可通过截面刚度优化控制局部应力集中及扭转变形。本文提出的“支座偏心+预应力针对性配置+主梁截面刚度优化”的设计策略可为复杂地形条件下曲线矮塔斜拉桥设计提供参考。

Taking a curved railway extradosed bridge overcrossing an expressway as the research object， this paper reveals the influence of curvature effect on the structural mechanical characteristics via the finite element analysis method， and proposes corresponding reasonable design countermeasures. The research results indicate that significant reaction differences exist among the bearings of main piers in the curved segment due to the centrifugal effect. Optimizing the bearing layout scheme can effectively coordinate the mechanical performance of the inner and outer sides of the structure， and mitigate the adverse impact of pier-top bending moment on the substructure. The spatial effect of stay cables in the curved segment leads to an asymmetric distribution of pylon bending moment. Thus， targeted arrangement of prestressed steel tendons in the pylon cross beams is required to counteract the influence induced by the spatial effect and guarantee the structural safety of the pylon. Meanwhile， the curvature effect has an amplification effect on the torque and transverse bending moment of the main girder; local stress concentration and torsional deformation can be effectively controlled through section stiffness optimization. The design strategy of "bearing eccentricity and targeted prestress arrangement and main girder section stiffness optimization" proposed in this paper can provide a technical reference for the design of curved extradosed bridges under complex terrain conditions.