The Guangdong Provincial Communications Group announced on the 2nd that the east and west anchor blocks of the Lingdingyang Bridge, each weighing about 1 million tonnes, have been completed. The bridge is a core project of the Shenzhen-Zhongshan Link in the Guangdong-Hong Kong-Macao Greater Bay Area. The crossbeams of the bridge's east and west main towers have also been poured, accelerating overall construction.

Photo courtesy of Guangdong Provincial Communications Group

The Shenzhen-Zhongshan Link is a cross-sea cluster project integrating "bridges, islands, tunnels and underwater interchanges", with a total length of about 24 kilometers. The Lingdingyang Bridge is the world's largest-span sea-crossing steel box girder suspension bridge, with a main span of 1,666 meters. The bridge has two anchorages, east and west, which are key control works of the Shenzhen-Zhongshan Link bridge project. Each anchor block is 61.14 meters long, 83 meters wide and 38.51 meters high, with a single area equivalent to 17 international standard basketball courts. Once completed, each anchorage weighs about 1 million tonnes.

At present, both the east and west anchorages of the Lingdingyang Bridge have been completed. "The anchorage is a key load-bearing component of a suspension bridge, used to anchor the main cables, and its role is like two weights," said Chen Huanyong, an engineer from the Chief Engineer's Office of the Shenzhen-Zhongshan Link Management Center. The Lingdingyang Bridge anchorage is the first in China to adopt an 8-shaped sea-based diaphragm wall foundation. The anchorage foundation is embedded deep in moderately weathered granite, and there is little experience to draw on. At the same time, because the anchorages are entirely in water and have many inclined and upward-facing surfaces, with the largest backward-inclined surface reaching 47.5 degrees, construction difficulty is greatly increased. During construction, the team also had to overcome complex conditions in the Pearl River Estuary such as strong winds, rough waves and frequent typhoons, as well as challenges including difficult offshore raw material supply, coordinated organization of overlapping works, and crack control in mass marine concrete pouring.

To build the giant anchorages, the construction team first adopted the cofferdam island-building technique to convert the marine construction environment into a land-based one, creating a 31,500-square-meter oval construction area at sea, and then carried out construction of the diaphragm walls, anchorage foundations and anchor block pouring.

According to technicians from the Poly Changda Shenzhen-Zhongshan Link S05 section, the west anchorage anchor block required 92,000 cubic meters of concrete, posing the challenge of pouring super-large-volume concrete in a high-temperature, high-humidity and high-salinity marine environment. The construction team continuously optimized the mix proportion of high-performance marine concrete. In addition to conventional temperature control measures, they added physical cooling with fog cannon machines and curing with water-retaining membranes to control concrete temperature and ensure that concrete quality met requirements.

At present, the Shenzhen-Zhongshan Link project is going all out to accelerate construction while ensuring safety and quality. On November 29, the 18th immersed tube section of the undersea tunnel was successfully lowered and connected. At 17:00 on December 1, after 42 hours of continuous concrete pouring, the upper crossbeam of the west main tower of the Lingdingyang Bridge was completed.

So far, construction of the upper, middle and lower crossbeams of both the east and west main towers of the Lingdingyang Bridge has been completed, officially forming a portal structure for the towers and significantly improving stability. Next, the Lingdingyang Bridge will steadily advance superstructure construction such as saddle hoisting and catwalk installation.

At present, all aspects of the Shenzhen-Zhongshan Link construction are advancing in parallel. The connected length of the undersea immersed tube tunnel has reached 2,764 meters, all bridge works have shifted to superstructure construction, the Zhongshan Bridge has entered the steel box girder erection stage, and construction of the east and west artificial islands is proceeding in an orderly manner.