福厦高铁泉州湾跨海大桥桥塔设计

Pylon Design for Quanzhou Bay Sea-Crossing Bridge on Fuzhou-Xiamen High-Speed Railway

新建福州至厦门高速铁路泉州湾跨海大桥处于宽阔海湾水域和海洋腐蚀环境,主桥为主跨400m双塔双索面斜拉桥,采用半飘浮体系,并行泉州湾公路大桥。结合并行公路桥的桥塔形式,通过多个塔型方案的设计和比选,确定桥塔采用贝壳造型的曲线H形塔,实现与并行公路桥的景观协调。桥塔采用圆弧曲线塔柱,横梁与塔柱全圆弧衔接;钢锚梁结构采用钢锚梁+钢牛腿的组合结构,钢牛腿壁板设计为变角度的等宽平行四边形以适用曲线塔柱特点,针对铁路斜拉桥受力特点,提出了桥塔钢锚梁结构的施工阶段体系转换方法和运营阶段传力设计模式。桥塔混凝土结构综合采用高性能混凝土、表面涂装、设置防裂钢筋网等耐久性措施,钢锚梁结构采用免涂装镍系耐海洋大气腐蚀钢。

The Quanzhou Bay Sea-crossing Bridge on the newly-built Fuzhou-Xiamen High-speed Railway crosses the vast Quanzhou Bay where the marine environment is quite challenging for corrosion protection of the structure.The main bridge,parallel with the alignment of the Quanzhou Bay-crossing Highway Bridge,is a cable-stayed bridge of semi-floating system.The bridge has two pylons and the stay cables are fanned out in double cable planes.Based on the aesthetic elements of the pylons of the existing highway bridge and analysis of several other options,the pylons are finally designed as the curve-line H-shaped structures,echoing the image of shell and achieving the landscaping harmony.The pylon legs are with curved lines,and the cross beams and the pylon legs are specially treated to realize the full-circular matching.The anchorages of stay cables in the pylons incorporate the steel anchor beams and the steel brackets.The plate of the steel bracket is a parallelogram with four equal sides,but variable angles,so as to suit the curve line of the pylon legs.In accordance with the load bearing behaviors of the railway cable-stayed bridge,the solution for system transformation during the construction of the steel anchor beams was proposed and the load transfer modes in the operation period were designed.To address the corrosion issues,the pylons were cast with high-performance concrete,coated and fitted with cracking-prevention reinforcement mesh.The steel anchor beam structure is made of coating-free nickel steel that is durable in marine environment.