自锚式悬索桥主缆架设施工技术

THE MAIN SUSPENSION CABLE ERECTING TECHNOLOGY OF SELF-ANCHORED SUSPENSION BRIDGE

江阴市新沟河大桥主桥为双索面钢筋混凝土自锚式悬索桥,主梁采用5跨连续预应力钢筋混凝土加劲梁形式。作为自锚式悬索桥,其施工工艺为先梁后缆,将主缆锚固于成型的主梁上,利用主梁来抵抗水平轴力;而主缆则通过吊索传递、承担着桥梁上部结构的全部恒载和使用期的全部活载。由于主缆架设线形对悬索桥结构的几何形状有着强烈的敏感性,其架设线形误差将引起悬索桥成桥线形和内部应力分布较大的改变。同时,主缆施工过程中自身也具有强烈的几何非线性,温度、施工和制作误差等对主缆的架设线形影响非常敏感,其成型质量对主桥的成桥精度和桥梁使用寿命起决定性作用,是悬索桥施工的关键工序。以江阴市新沟河大桥为例,介绍自锚式悬索桥主缆架设的施工技术。

Xingou River Bridge in Jiangyin City is a self-anchored suspended bridge with double cable planes, the main girdes are five consecutive span prestressed concrete stiffening girders. As a self-anchored suspended bridge, the construction sequence is the girder first and then the cable, the main cable is anchored in the constructed main girder that bears the horizontal axial force, and the main suspension cable of suspension bridge bears all the permanent and live loads transmitted by hoisting cables. Because of the strong sensitivity of main cable erection line to the geometry of bridge structure, its erection linear error will cause great changes to the constructed bridge linear and internal stress distribution. Meanwhile, the main cable construction process itself has strong geometrical nonlinearity, the influence of temperature, construction and manufacturing error on main cable erection line is very sensitive, and the quality of the shape will be the decisive factor to the precision and service time of the bridge. Erecting the main suspension cable is a critical sequence in the construction of the bridge. It was introduced the construction technology of the self-anchored suspension bridge with the example of the construction of Xingou River Bridge in Jiangyin City.