At 10:26 on June 28, with the hoisting of the last arch rib segment of the main arch into place, the main arch of the Yibin Jinsha River road-rail bridge—a control project on the world's first mountain high-speed railway, the Chengdu-Guiyang Railway—was closed.
The Jinsha River Bridge is 1,875 meters long and will set four bridge construction records upon completion: its configuration with the railway deck above and the highway deck below is the first of its kind for a road-rail bridge in the world; its main span of 336 meters makes it the world's longest-span steel box arch bridge; the 32-meter height difference between the highway deck and the railway deck is the world's largest; and its system combining flexible hangers on the highway deck with rigid hangers on the railway deck is the first of its kind in China for a road-rail steel box arch bridge.
“This bridge involves every type of bridge structure,” said Ji Yuehua, deputy general manager of China Railway Major Bridge Engineering Group and project manager of the Chengdu-Guiyang Railway project department. The bridge includes both a parallel steel box arch bridge and a basket-type concrete arch bridge, covers three arch structures—deck arch, half-through arch and through arch—and uses four types of girders: steel box girders, continuous rigid frames, continuous girders and simply supported girders. With such a diversity of bridge types, each requiring different construction techniques, and with the turbulent waters of the Jinsha River, work must be carried out “in midair” at heights of more than 300 meters in length and up to 200 meters, making construction extremely difficult. Construction began in January 2014, with a total of 5 major and 15 minor technical research topics; these research results will provide references for similar projects in the future. The main-span steel girder is expected to be closed by the end of October this year, and the bridge is scheduled for completion by the end of the year.
The Chengdu-Guiyang Railway is 519 kilometers long, with a total investment of about 78 billion yuan and a design speed of 250 kilometers per hour. It runs through Sichuan, Yunnan and Guizhou provinces and crosses the Dadu, Jinsha and Min rivers. It is one of the landmark projects of the country's new round of western development. After it opens to traffic at the end of 2019, travel from Chengdu to Guiyang will be shortened from about 12 hours to about 3 hours, and to Guangzhou to only about 7 hours, making it the fastest railway route southward out of Sichuan.