连续钢桁拱双悬臂架设用水平拉索设计与施工

Design and Construction of Horizontal Cables for Erection of Continuous Steel Truss Arches Using Double Cantilever Method

南京大胜关长江大桥主桥4～10号墩为6跨连续钢桁拱,其7号墩墩顶钢桁拱采用双悬臂架设施工,架设过程中分阶段挂设3层水平拉索。第一层水平拉索沿钢桁梁梁面上展开,第二、三层水平拉索沿位于已挂水平拉索索面上的猫道展开;利用架梁吊机和张拉千斤顶配合进行水平拉索的挂设张拉。利用Mathcad软件对张拉过程中水平拉索的变化进行分析计算,计算结果表明,在既有索面上进行展索可有效降低展索过程中拉索的牵引力,同时对既有拉索的索力影响不大。

The No.4-10 piers of Nanjing Dashengguan Changjiang River Bridge are composed of six spans continuous steel truss arches.Steel truss girder on top of the No.7 pier is erected by the double cantilever erection method,and three levels of horizontal cables are installed during its erection.The first level of horizontal cables spread along the surfaces of steel truss girders and the other two spread along catwalks that allocated on surfaces of cables already installed.The installation and tension of horizontal cables are finished by collaboration of girder erection cranes and tensioning jacks.Analysis and calculations of force change of cables are conducted by using the Mathcad software.Calculation results show that spreading new cables on the surface of installed cables can effectively reduce the tractive force of new cables during their tension process,while no significant effects will be made on force distribution of installed cables.