On July 24, good news came from the construction site of the Shanghai-Chongqing-Chengdu High-Speed Railway: the first 56-meter section of the non-navigable-span road-rail dual-purpose continuous steel truss girder of the Chongqi Road-Rail Yangtze River Bridge was pushed into place in four incremental launches, creating favorable conditions for the subsequent erection of steel girders and continuous incremental launching construction.

The Chongqi Road-Rail Yangtze River Bridge is the world's largest multi-span, long-unit ballastless-track steel truss composite continuous girder bridge. The non-navigable-span bridge is a double-deck, constant-depth continuous steel truss composite girder with a main span of 112 meters. Its span arrangement consists of one continuous unit of (99.2+9×112+98.2)=1205.4 meters, with a triangular truss configuration. The steel truss girder is 15 meters high, with 11 spans per unit and a total of 86 panels. The main girder adopts a one-way continuous incremental launching construction method. Its multi-point, synchronous, long-unit, continuous incremental launching technique is highly challenging, and the single-unit one-way launching distance ranks among the longest in the world.

According to Zhang Xiaobo, deputy chief engineer of the First Division of the Chongqi Road-Rail Yangtze River Bridge Project of China Railway Major Bridge Engineering Group, the riverbed of the non-navigable-span bridge is severely silted, with a water depth of only 2.5 meters at the lowest tide, making it impossible to use large equipment for integral assembly of large segments. Therefore, only the construction technique of piece-by-piece assembly of members plus continuous incremental launching could be adopted. The steel girders were prefabricated in a professional steel structure fabrication base and transported to the assembly area at the south bank dike of the north branch of the Yangtze River. Using a 120-ton gantry crane on the assembly supports, the launching nose and steel truss girder members were assembled one by one into shape, and then the steel girder was continuously launched round by round from the bank toward the main navigation channel of the Yangtze River by jacks. Because the Shanghai-Chongqing-Chengdu High-Speed Railway adopts a ballastless track design, the precision control requirements are extremely high, so the geometric alignment control of steel girder assembly is very strict, and with the large number of launching devices, synchronous control is difficult. The incremental launching of the non-navigable-span bridge is divided into 13 rounds and 87 launches in total, with each launch advancing 14 meters, and the first round launching 56 meters.

The Chongqi Road-Rail Yangtze River Bridge crosses the north branch of the Yangtze River and adopts a road-rail combined bridge scheme of 2 high-speed railway tracks + 2 intercity railway tracks + 6 highway lanes. It consists of the main navigable-span bridge, the non-navigable-span bridge, the north and south bank road-rail combined approach bridges, and the north and south bank railway-only approach bridges. It is a key controlling project of the newly built Shanghai-Nanjing-Hefei High-Speed Railway. Upon completion, the project will be of great significance for promoting the integrated development of the Yangtze River Delta and building a comprehensive three-dimensional transportation corridor for the Yangtze River Economic Belt.