穗莞深城际铁路东江南特大桥主桥快速施工技术

Rapid Construction Technology for Dongjiang South Bridge of Guangzhou-Dongguan-Shenzhen Intercity Railway

研究目的:随着城际铁路的快速建设,形如悬索桥的上加劲连续钢桁梁桥梁结构会越来越多。该桥结构形式新颖,但主梁在大悬臂安装时结构强度不足,常规方法安装较为困难。桥梁施工受到航道运输、潮位变化、造价偏低等因素影响,需要研究一种经济、安全、快速的基础施工和钢梁安装的方法,确保施工工期和节省施工成本。研究结论:该桥在基础施工和上部结构安装的过程中,采用了采用多项快速的桥梁施工技术,结果表明:(1)采用标准化施工栈桥,搭建安全快捷、构件单元周转率高、制造和安装成本较低;(2)采用钢漏斗堵漏止水的无封底吊箱围堰施工主墩承台,可有效减少封底混凝土数量,减轻围堰的设计重量,缩短承台的施工周期,节省成本约50%。(3)上部结构安装采用在中跨加劲弦间设置临时拉索辅助的单悬臂安装方案,可克服主梁悬臂安装结构强度不够的难题,成倍地减少桥面吊机的数量,不需设置吊索塔架辅助结构以及跨中的临时支墩,节省成本约80%。(4)主梁安装主墩不起顶而边墩起落梁的安装方法,可减少大型千斤顶投入,施工操作安全快捷,经济效果显著;(5)这种桥梁快速的施工方法,可为今后受潮汐影响的承台施工和上加劲弦钢桁梁安装提供借鉴和参考。

Research purposes： With rapid construction of the intercity railways, the more and more upper stiffened continuous steel truss bridge structure like suspension bridge will be used. The structure of such kind of bridge is fresh, but its main beam has not enough strength when the utmost cantilever is assembled. So it is difficult to assemble it with the conventional methods. The bridge construction is often affected by the navigation, tide change and low construction budget. Consequently, it is necessary to research a economical, safe and quick method for the foundation construction and steel -beam assemble to ensure the construction procedure and save the construction cost. Research conclusions：Many rapid construction technologies were used for the foundation construction and erection of the superstructure. The applicable results show ： （ 1 ） Application of the standardized construction for the trestle bridge and application of the rapid and safe member can make the turnover rate of the member more rapid and the manufacture and erection costs lower. （2） Application of suspension box - cofferdam which is sub - sealed with funnel instead of concrete for the cushion cap of the main pier, can effectively reduce the concrete quantity for sealing the bottom, lighten the design weight of cofferdam and shorten the construction period of cushion cap and cut the cost by 50%. （3） For construction of the superstructure, application of the one - end - cantilever - assemble way along with the temporary stay cables fixed between stiffening beams of medium span can overcame the problem of strength deficiency of the main beams when the utmost cantilever is assembled, much reduce the crane amount, have no assisting cable tower and temporary piers within the span and cut the cost by 80%. （4） For construction of the main beam, application of the erection method that the beam is not jacked up on the main piles while the beam is jacked up or laid down on the side piers can reduce the large jack quantity and ensure the construction safety, getting the notable economical effect. （5） This rapid construction method for the bridge can provide the reference to construction of cushion cap and erection of the upper stiffened continuous steel truss bridge affected by tide.