松原市天河大桥北汊主桥钢-混结合段施工技术

Construction Techniques for Steel-Concrete Joint Section of North Main Bridge of Songyuan Tianhe Bridge

松原市天河大桥北汊主桥为双塔空间索面自锚式钢-混组合梁悬索桥,跨径布置为(40+100+266+100+40)m,钢-混结合段长2m,位于锚跨距桥塔89m处。单重37t的结合段钢梁节段使用150t履带吊进行吊装。钢-混结合段先安装PBL键,然后安装钢筋,纵向、横向均设有预应力筋。结合段混凝土使用C55聚丙烯纤维混凝土进行浇筑。在混凝土浇筑过程中,使用劲性骨架锁定与预应力张拉锁定相结合的方法对钢梁进行锁定,对钢梁在温度变化产生的膨胀与收缩都起到了良好的约束作用,控制了钢-混结合段混凝土浇筑和养生过程中内部应力的变化,有效地避免了在梁体浇筑完成后出现的裂缝现象。

The north main bridge of Songyuan Tianhe Bridge, Located in Songyuan City, is a two-tower self-anchored suspension bridge with span arrangement of （40 ＋ 100 ＋ 266 ＋ 100 ＋ 40） m. The cables are spatially arranged and the stiffening girder adopts the steel-concrete composite girder. The steel-concrete joint section is 2 m long, located where the anchoring span is 89 m away from the bridge tower. The steel girder section in the joint section weighs 37 t on itself, erected by the crawler crane of a capacity of 150 t. In the construction of the steel-concrete joint section, the PBL shear connectors were installed prior to the installation of reinforcement, and prestressing tendons were placed in the longitudinal and transverse directions. The concrete cast in the joint section was the C55 polypropylene fiber concrete. During the concrete casting, the steel girder was locked by the method of the combined use of stiffening skeleton locking and prestress tensioning locking, which exerts favorable restriction effect on the expansion and contraction caused by temperature variation, controls the changes of the internal stresses during the concrete casting and cu-ring in the steel-concrete joint section, and effectively avoid the girder cracking after the concrete casting.