沪通长江大桥跨横港沙112m简支钢桁梁全悬臂架设安装技术

Full-Cantilever Erection Techniques for 112m Simply-Supported Steel Truss Girder Crossing Henggangsha of Hutong Changjiang River Bridge

沪通长江大桥横港沙浅水区域桥梁上部结构为21孔112m简支三主桁钢桁梁,采用"首跨膺架法搭设、其余跨全悬臂拼装、先连续后简支"的安装方法。通过采取优化上墩方式、公路纵梁后安装、连续墩墩顶设置双排支撑等措施,减小了钢桁梁在大悬臂施工条件连续墩墩顶区域应力偏高问题,有效地降低了施工风险。通过采取在连续墩墩顶设置横向限位装置、在墩顶设置纵向限位装置等措施,确保钢梁大悬臂状态下遭遇突风或台风时的横向稳定性。

The part of the Hutong changjiang River Bridge crossing the Henggangsha shallow water area is a steel truss girder structure formed of three truss blocks, arranged in 21 spans, each 112 m long. The steel truss sections in the first span were erected by using scaffoldings, the re-maining spans were erected by full-cantilever assembly, and the system was transformed from a continuous to a simply-supported structure. The high stress problem in the top zone of the contin-uous piers was effectively reduced by taking several measures, including optimizing the way of mounting the truss blocks on pier tops, installing the highway stringers later, placing two rows of supports on the top of the continuous piers, and the construction risk was also effectively reduced.The transverse restriction devices on the top of the continuous piers and longitudinal restriction de-vices on the pier top were installed to ensure the transverse stability when the bridge was in the large cantilever state or attacked by the abrupt wind or typhoon.