The Dajiang Bridge of Zhixi Changjiang River Bridge is a single span suspension bridge with a main span of 838 m.The catwalk has a total length of 1 350 m.The traction ropes were used as pilot ropes in the river-crossing erection of the catwalk.Due to that the catwalk erec-tion met the flooding period of the Yangtze River and closure of the navigational channel as well, the pilot ropes of the catwalk could not be erected by the"water surface transition"method.Ac-cording to the design and study of the schemes,it was determined to erect the pilot ropes of the catwalk by the overhead transverse moving method.In the operation,the sliding deviation devices were installed on the downstream tower-head portal frames,the pilot ropes were guided to the north tower by the downstream traction ropes,and then transversely moved to the upstream side in the air via the sliding of the deviation devices and the erection of the pilot ropes were realized. The sliding devices were installed by using the auxiliary winch with a capacity of 10 t.At each foot of the portal frames on the tops of the downstream towers on both river banks,a single pulley was installed.The steel wire ropes of the auxiliary winch were threaded through the sliding pulley to connect with the 16 t snap rings.The pilot ropes were deviated after being threaded through the snap rings.And the auxiliary winch was used to uncoil the rope,to realize the transverse moving of the pilot rope.The pilot ropes of the upstream catwalk were erected by the overhead transverse moving method,the river-crossing of the pilot ropes took 3 h and the erection process was smooth.%至喜长江大桥大江桥为主跨838 m的单跨悬索桥,猫道全长1350 m,利用牵引索作为导索进行过江架设,架设时正值长江汛期,由于封航原因上游侧猫道先导索无法采用"水面过渡法"架设.通过方案设计研究,上游侧猫道先导索采用高空横移法架设,即在两岸下游塔顶门架上设置可滑动转向装置,利用下游牵引索将先导索牵引至北塔后,通过转向装置滑动,在空中将先导索横移至上游侧,实现先导索架设.可滑动转向装置利用塔顶10 t辅助卷扬机设置,在两岸下游塔顶门架柱脚处设置1台单门滑车,将辅助卷扬机钢丝绳穿过滑车后连接16 t卡环,先导索穿过卡环后进行转向,通过辅助卷扬机放绳,实现先导索横向移动.该桥上游侧猫道先导索采用高空横移法架设施工,历时3h完成先导索与导索牵引过江,架设过程顺利.
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