大跨度系杆拱连廊施工方法及其关键技术研究

Research on the Construction Method and Key Technologies of Large-Span Tie Arch Skybridges

广州报业文化中心1#连廊为大跨度系杆拱结构,结构体系复杂,钢结构安装、预应力张拉、临时支撑胎架卸载、混凝土浇筑等施工工序相互交叉,故施工方法对结构内力及变形有较大影响。基于施工全过程仿真分析,综合考虑施工过程的安全性、便利性及经济性,对预应力张拉顺序、临时支撑胎架卸载时机及卸载顺序进行了对比。结果表明,采用先张拉系杆索再张拉吊杆索,待拱肋混凝土达到设计强度后再从中间向两端卸载临时支撑胎架的施工方案,施工完成时结构受力状态与设计状态吻合较好。总结了大跨度系杆拱连廊施工关键技术,包括合理施工工序的确定、预应力穿索与锚固节点的优化、预应力张拉方案的制定、拱肋混凝土浇筑质量保障措施、临时支撑体系的设计以及施工过程监测等,为工程顺利实施提供了保障,施工过程安全可控,可为类似工程施工提供参考。

No.1 skybridge of Guangzhou Daily Group Culture Center is a large-span tie arch skybridge with complex structural system.Steel components installation,prestressed cable tensioning,temporary supports unloading,concrete casting and other construction can influence each other.The construction method has a great impact on the internal force and deformation of the tie arch structure.Based on the whole process construction simulation,this paper compares different prestressed tensioning sequences,temporary support unloading sequences and unloading time with consideration of safety,convenience and economy benefit of construction.The results show that,under the construction scheme with the hanging bars tensioned after tie bars and the temporary supports unloaded from middle of the skybridge to both ends after concrete filled arch reach its design strength,the loading status after construction is in great agreement with the design status.The construction key technologies of large-span tie arch skybridges are summarized,including the determination of reasonable construction process,the optimization of prestressed cable crossing and anchoring node,the formulation of prestressed cable tensioning scheme,the concrete casting quality assurance measures of arch rib,the design of temporary supporting system,and construction process monitoring,which guarantees the project successfully constructed with safe and controllable construction process,which can provide a reference for similar projects.