On the afternoon of May 30th，The first and second sections of the world's largest round dumbbell steel cofferdam are accurately hoisted into place，It marks that the world's first double-deck cable-suspension cooperative system bridge, G3 Tongling Yangtze River Railway Bridge No. 3 main pier, which is invested by the Municipal Investment Group and built by China Railway Bridge Bureau, has officially entered the construction stage of large volume cap，Great progress has been made in the construction of the bridge。

　 Steel cofferdams are enclosures made in the construction of water conservancy projects in deep water, which can prevent water and soil from entering the construction position, so as to drain and excavate the foundation pit in the cofferdam。

　 "The steel cofferdam of the No. 3 main pier is designed as a round dumbbell steel casing box structure with a length of 104.6米，宽51.2米，高32.5m, a total weight of about 3950 tons, equivalent to an area of 10 basketball courts of 11 storey building, is the world's largest dumbbell steel cofferdam。China Railway Bridge Bureau G3 Tongling Yangtze River Railway Bridge project branch chief engineer Song Haitao introduced that the No. 3 main pier steel cofferdam is divided into 5 sections, divided into 3 times of transport and installation。The first and second sections will be installed at 4 meters and 8 meters in height and weigh 751 tons and 815 tons, respectively。After production in Zhangjiagang factory, Jiangsu Province, by the load capacity of 14,500 tons of self-propelled deck cargo ship, upstream 420 kilometers to the predefined pier, with two large floating cranes for double-machine lifting installation。

　 China Railway Bridge Bureau G3 Tongling Yangtze River Gongtie Bridge No. 3 main pier chief Shen Jianyu introduced that the No. 3 main pier steel cofferdam has the characteristics of large area, large volume, super long, super wide and super high transportation difficulty, high synchronization requirements of double floating crane hoisting, heavy task and long cycle。We follow the construction concept of G3 bridge "scientific organization, innovation for stability, stability for good, good for fast"，By ensuring material supply, organizing technical research, investing special equipment, increasing personnel organization, strengthening process control and other measures，Experts were organized to compile a special construction plan，Large transport ships and lifting boats are used，Maritime authorities are requested to provide guidance on safe navigation，Ten specialized work teams have been set up，Several hoisting exercises were carried out，Ensure the smooth manufacturing and installation of this' behemoth '。

　 G3 Tongling Yangtze River Highway and Railway Bridge is one of the river crossings planned in the Yangtze River Trunk Line Crossing Passage Layout Plan (2020-2035)，It is a key project to implement the integrated development strategy of the "Belt and Road" Initiative, the Yangtze River Economic Belt and the Yangtze River Delta，It is also a major infrastructure construction project in Anhui Province，Tongling is based on the Yangtze River Economic belt，It is an important project to accelerate the integration into the Hefei metropolitan area and the Yangtze River Delta。After the completion, it is of great significance for building a copper development belt, comprehensively promoting the construction of international cultural tourism demonstration zone in southern Anhui, accelerating the coordinated development of regional economy, strengthening the interconnectivity of the Yangtze River Delta, and building a modern comprehensive transportation system。