The main bridge of the Second Jiujiang Changjiang River Bridge is a two-pylon six-span asymmetrical hybrid girder cable-stayed bridge with a main span of 818 m and with double ca-ble planes .The stay cables are composed of the φ7 mm parallel steel wires ,each having a nominal tensile strength of 1 670 MPa .By the comparative analysis of the dragging construction techniques of dragging carried out by hoisters ,soft dragging ,strong dragging and a combination of the two , it was determined to drag the stay cables via a combined application of the above dragging tech -niques ,taking into consideration of the facts that the stay cables are very heavy and long and the difference between the cable forces in the central span and the side spans are great .According to the actual characteristics of the construction ,the auxiliary facilities for the stay cables installation were prepared ,including lifting portal mounted on pylon tops and the platform used to drag the ca-bles into the anchorages on the girder ,by which the problems of the insufficient hoisting capacity and the difficult installation of the dragging devices were resolved .To improve the efficiency of stay cable installation ,the short cables were installed by the steel strand elongation method ,effec-tively reducing the dragging force in the pressing anchorages in the girder and accelerating the speed of the cable′s entering into the anchorages in the girder .The long cables were dragged into the anchorages by the soft dragging and combined application of the aforementioned methods ,re-solving the difficulty of dragging the long cables into the anchorages in the girder .%九江二桥主桥为主跨818 m 的六跨不对称双塔双索面混合梁斜拉桥，斜拉索采用平行钢丝斜拉索，钢丝直径7 mm ，抗拉强度标准值1670 MPa 。通过对卷扬机牵引、软牵引、硬牵引及软硬组合牵引等牵引施工工艺的对比分析，结合该桥的斜拉索超重超长、中边跨索力差别大等特点，确定该桥斜拉索综合运用上述牵引工艺进行牵引。根据实际施工特点，设计了塔顶提升门架、梁端入锚施工平台等斜拉索安装辅助设施，有效解决了吊装能力不足、牵引设备安装困难等难题。为提高斜拉索安装工效，短索采用钢绞线接长法施工技术，有效降低梁端压锚的牵引力，加快了短索梁端入锚速度；长索采用梁端软牵引或组合牵引入锚方式，解决了长索梁端入锚困难的难题。
展开▼
