马鞍山长江公路大桥左汊主桥为主跨2×1080 m的三塔两跨悬索桥，主缆牵引系统采用先导索过江架设，先导索设计总长2600 m ，分2段，每段1300 m。针对桥址江面宽、悬索桥需两跨过江、跨越长江“黄金航道”、安全要求高、工期紧等因素，对先导索过江方案进行比选，确定该桥先导索采用飞艇过江牵引方案架设。采用T C08X‐2．4G型遥控氦气飞艇牵引先导索，选用φ2 mm迪尼玛绳作为一级导索，采用被动放索装置的力矩电机被动放出先导索。首先由北岸向中塔飞行过江，形成北跨初级牵引系统；然后由中塔向南岸飞行，形成南跨初级牵引系统；最后由人工和卷扬机配合完成1～5级先导索替换，完成先导索过江。飞艇牵引过程中，进行飞行控制、先导索垂度控制和安全控制，保证先导索飞艇过江顺利实施。实践表明，在长江江面不封航情况下，采用飞艇过江牵引方案可以实现先导索安全可靠过江。%The left main bridge of the Maanshan Changjiang River Highway Bridge is a three‐tower suspension bridge with two main spans each of 1 080 m. The traction system for the main cables was erected by using pilot ropes which needed threading across the river .The pilot rope had a total design length of 2 600 m ,which was divided into two sections ,each measuring 1 300 m . Given the fact that the river is wide at the bridge site ,the suspension bridge needs two main spans to cross the river ,more critically ,the suspension bridge crosses the golden navigation channel of Changjiang River ,its safety requirements are demanding and construction schedule is tight ,it is determined via scheme comparison and selection that the pilot ropes be erected by using airship to guide the ropes to cross the river .The TC08X‐2 .4G remote‐controlled helium airship was adopted to guide the pilot ropes .Theφ2 mm Dyneema rope was used as the first grade pilot rope and the pilot rope was uncoiled passively by torque motor ,a kind of passive rope uncoiling device .First , the airship flied from the north bank to cross the river and stopped at the top of the intermediate tower ,forming the preliminary traction system of the north span .Then the airship started flying from the intermediate tower top towards the south bank of the river ,forming the preliminary trac‐tion system of the south span .At last ,the operatives used winches to finish the replacement of the grade Ⅰ to grade Ⅴ pilot ropes ,completing the river‐crossing construction of the pilot ropes .Dur‐ing the airship guiding process ,the flying of the airship ,verticality of the pilot ropes and the safe‐ty of both the airship and pilot ropes were controlled ,ensuring that the river‐crossing construction of the pilot ropes be conducted smoothly .The engineering practice proves that when the river is not closed for navigation ,the scheme of using airship to guide the pilot ropes to cross the river can realize the safe and sound river‐crossing construction of the pilot ropes .
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