跨繁忙铁路转体矮塔斜拉桥拉索施工技术

Cable-Stayed Construction Technology of Swivel Low-Tower Cable-Stayed Bridge Across Busy Railway

结合永修万宝路上跨繁忙的京九、昌九铁路(95+160+95)m预应力混凝土转体矮塔斜拉桥项目,分析了拉索施工的重难点,研究了既有线斜拉索施工风险与控制技术、分丝管索鞍安装控制技术、单根挂索与张拉技术、全桥单根循环调索技术、索力监测技术等。实践表明:梁面的汽车吊布置在远离既有线一侧等措施,确保了拉索施工安全;采用劲性骨架定位法定位分丝管索鞍,确保了定位精度;采用两次张拉调索技术,通过第一次张拉后索力及第二次张拉后索力与其对应理论索力的对比分析,偏差均在5%以内,保证桥梁的线形、内力达到了设计要求;创新采用锚索计法和频谱法相结合的索力监测方法,为桥梁运营期索力精确监控提供依据。

Combined with the busy Beijing-Kowloon and Chang-Kowloon railways(95+160+95)m prestressed concrete swivel low-tower cable-stayed bridge project on Yongxiu Wanbao Road, the major and difficult points of cable-stayed construction were analyzed, and the construction of cable-stayed cables on existing lines was studied, including the risk and control technology, cable saddle installation and control technology for wire-splitting pipe, single hanging cable and tensioning technology, single circulating cable adjustment technology for the whole bridge, and cable force monitoring technology. Practice has shown that: the car crane on the beam surface is arranged on the side away from the existing line, which ensures the safety of the cable construction;the rigid frame positioning method is used to locate the wire harness saddle, which ensures the positioning accuracy;two tension adjustment cables technology are used, through the comparative analysis of the cable force after the first tension and the cable force after the second tension and its corresponding theoretical cable force, the deviations are all within 5%, ensuring that the line shape and internal force of the bridge meet the design requirements. The innovative use of cable force monitoring method combining the cable counting method and the frequency spectrum method provides the basis for the accurate monitoring of the cable force during the bridge operation period.