China Poured Concrete for 60 Hours Straight to Build the World's Largest Bridge Caisson

China completed a major foundation stage on the Hannan Bridge over the Yangtze River in Wuhan, Hubei Province, after maintaining non-stop concrete pouring for 60 consecutive hours on the south anchorage of the structure. The operation marked the completion of the first phase of raising what the construction company describes as the world's largest caisson in a road project.

A caisson, in civil engineering, is a large foundation structure used to support bridges, pillars, or anchorages, particularly in areas with complex soils, flooded terrain, or riverbanks. In the case of the Hannan Bridge, this base will absorb and transfer the forces generated by the main cables of the future suspension bridge. The south anchorage caisson measures 76.4 metres by 76.4 metres in plan and 43 metres in height, divided into 36 internal cells to allow for staged construction, controlled sinking, and geometric monitoring during installation.

The bridge itself is planned with a main span of 1,600 metres, two towers, eight traffic lanes, and a steel box deck designed for speeds of up to 120 kilometres per hour. Road and Bridge International, a company linked to state-owned China Communications Construction Company (CCCC), said the bridge will integrate the metropolitan ring road of Wuhan and is described as the largest eight-lane suspension bridge with two main cables in Hubei Province. It will become the 13th crossing over the Yangtze in Wuhan once complete.

The 60-hour pour required rotating teams, continuous material supply, and technical monitoring throughout. To manage risks on the alluvial riverbank soil, the construction team reported using intelligent monitoring systems, foundation reinforcement techniques, and a cantilever formwork system. Temperature control was also a key concern: large concrete masses generate heat during curing, and internal thermal differences can create stress in the material if left unmanaged.

In May 2026, Chinese authorities announced the completion of both main towers. The north tower stands at 230.5 metres, while the south tower reaches 228.5 metres, the slight height difference adopted to compensate for varying topography on each bank. With the towers complete, the project is advancing toward cable installation, deck assembly, and road access integration. Local sources have indicated the bridge is on course for opening to traffic in 2028.

Most of the foundation work, including the caisson, will be out of sight once the bridge is in use. In suspension bridges, a significant portion of the engineering sits below the waterline and inside the anchorages, not on the visible span. The 60-hour concrete operation offers a clearer sense of what it takes to hold a 1,600-metre crossing in place before a single cable has been strung.