独塔单索面跨铁转体斜拉桥技术创新

Technological Innovation in Single-pylon Single-plane Cross-railway Rotational Cable-stayed Bridge

摘要:

嘉兴市快速路上跨沪昆铁路立交工程主桥采用（140 m+140 m） 2跨独塔混凝土斜拉桥。为研究该桥的受力特点、优化设计方案，针对宽幅箱梁第一、第二体系应力分别进行了总体和局部计算。计算时，考虑到钢筋混凝土桥塔索塔锚固区较易开裂，而采用传统钢锚梁或钢锚箱形式锚固时要求桥塔构造尺寸较大，在桥梁中央隔离带宽度有限的现状下，采用了鞍座式锚固方式来回避以上问题。研究表明：桥梁设计时通过综合考虑第一、第二体系应力，可优化主梁截面形式；通过控制主梁刚度，可减少桥塔两侧不平衡索力；改用鞍座锚固形式，可优化主塔结构及受力状态。另外，通过采用大直径钢球铰，降低了转体施工过程中受压面应力，确保了转体安全性和稳定性。

Abstract:

The main bridge of the expressway crossing Shanghai-Kunming Railway interchange project in Jiaxing is a (140 m+140 m) two-span single-pylon concrete cable-stayed bridge. In order to study the force characteristics of the bridge and optimize the design scheme, the overall stress and local stress of the first system and the second system of the wide box girder is calculated respectively. In the calculation, considering that the anchoring area of the reinforced concrete bridge cable pylon is prone to cracking, the construction size of the bridge pylon is required to be larger when using the traditional steel anchor beam or steel anchor box form for anchorage. The saddle-type anchorage is used to avoid the above problems under the limited width of the central isolation belt of the bridge. The study shows that through comprehensive consideration of the first and second system stress, the section form of the main girder can be optimized during the bridge design. By controlling the stiffness of the main girder, the unbalanced cable force on both sides of the bridge pylon can be reduced. And by changing to the saddle anchor form, the structure and stress state of the main pylon can be optimized. In addition, by using large-diameter steel spherical hinges, the compressive stress on the stressed surface during the rotational construction process is reduced, and the safety and stability of the rotation is ensured.