松原市天河大桥北汊主桥上部结构施工关键技术

Key Construction Techniques for Superstructure of North Main Bridge of Songyuan Tianhe Bridge

松原市天河大桥北汊主桥为(40+100+266+100+40)m双塔空间索面自锚式悬索桥,桥塔采用钢筋混凝土人字形结构,主梁分为混凝土加劲梁以及钢-混组合梁(由格构式钢梁上铺混凝土桥面板组成)两部分,主缆呈空间三维线形,全桥共51对吊索。桥塔采用液压自爬模施工,通过设置主动支撑以及预偏量控制塔身倾斜度;格构式钢梁采用以直代曲制作,边跨钢梁采用吊机原位吊装,中跨钢梁采用拼装平台上整节段拼装牵引滑移施工;主缆锚固系统位于加劲梁锚墩横梁上,采用厂内预制现场整体吊装施工;主缆架设采用PPWS施工方法,猫道采用预制吊装施工;针对可转动索夹以及球铰底座的特点,改变传统的体系转换临时吊索的使用顺序,达到吊索一次张拉成型。

The north main bridge of Songyuan Tianhe Bridge is a two-tower self-anchored sus-pension bridge with span arrangement of （40 ＋ 100 ＋ 266 ＋ 100 ＋ 40） m and with spatial cable planes. The towers are reinforced concrete inverted Y-shaped structures （like the Chinese charac-ter ^ren？, or people. ）. The main girder comprises of the two parts of concrete stiffening girder and the steel-concrete composite girder （formed of the lattice steel beams with concrete deck slabs）. The main cables and the 51 pairs of hanger cables are arranged to form spatial three-dimensional planes. The bridge towers were constructed by the hydraulic self-climbing formwork, to which the active supports and pre-offsetting were set to control the inclination of the tower columns. The sections of lattice steel beams were fabricated with straight line rather than the curve line, the side- span steel beams were hoisted and installed at the designed locations. The central span steel beams were integrally assembled on the assembly platform, and then, dragged and slid into position. The anchoring system of the main cable, which is located on the anchor-pier cross beam of the stiffe-ning girder, was prefabricated in the factory, transported to the bridge site and integrally lifted and installed. The main cables were erected by the PPWS method and the catwalk was prefabricated and installed at the bridge site. In light of the characteristics of movable cable clamps and the plinths with spherical hinges, some changes were made to the conventional systematic transforma-tion system and the working sequence of the temporary hangers was adjusted, to make sure that the hanger cables could be tensioned to the required condition via one-off tensioning.