Chongqing - The world's first large-span continuous steel box truss arch bridge that is under construction, the No.7 of the Fenglai Daxi River Extra-large Bridge on the Chongqing Wulong-Liangjiang New Area Expressway (Wu-Liang Expressway), completed its building work in Chongqing on October 15. 

This marks the beginning of the steel structure construction phase of the mega-bridge.

Upon completion, the travel time from Wulong district to the central urban area of Chongqing will be reduced to one hour, further optimizing the highway network structure of Chongqing. This also strengthens the economic linkage among Wulong, Nanchuan, and Fuling districts, thereby promoting high-quality economic and social development in the surrounding areas.

No.7 of the Fenglai Daxi River Extra-large Bridge on the Chongqing Wulong-Liangjiang New Area Expressway is the world's first large-span continuous steel box truss arch bridge. (Photo/CREC8)

Significant construction challenges

"Thw No.7 of the Fenglai Daxi River Extra-large Bridge is a crucial milestone," said Huang Zhong, the Wu-Liang Expressway project Chief Engineer of China Railway No.8 Engineering Group Co., Ltd. (CREC8). 

Huang added, "The entire arch abutment consists of two parts, including the bottom foundation and the back wall foundation, resembling a chair embedded in the steep cliffs on both sides of the river, posing significant construction challenges." 

At the project's inception, both sides of the river were sheer cliffs covered in thorny bushes. Through step-by-step surveying and construction, a roughly 1.3-kilometer-long access road for arch abutment construction was finally carved out, solving waste disposal problems and concrete pouring for the arch abutment.

Meanwhile, the arch abutment's interior is laden with many embedded parts, with a demand for precision deviation of less than 1 millimeter. The project team collected data and utilized BIM technology to simulate the lifting construction in advance, providing robust support for the assembly of the first segment of the arch rib.

The bridge length reaches 1136.7 meters 

The Fenglai Daxi River Extra-large Bridge on the Wu-Liang Expressway reaches 1136.7 meters, with the main span measuring 580 meters. The bridge deck sits at 310 meters above the river surface. 

Being built by CREC8, with the design by China Railway Eryuan Engineering Group Co., Ltd, the main bridge is constructed using cable-stayed hoisting, inclined cable-stayed cantilever assembly.

No.7 arch abutment, which has been successfully constructed, serves as the key pier of the bridge. The transverse width of the arch abutment is 37.2 meters, the longitudinal length is 35.7 meters, and the height is 23 meters, equivalent to about eight floors high, with a total concrete volume of 12,910.2 cubic meters.

The Wu-Liang Expressway starts from the south of Pingqiao Town, connecting to the G69 Nanfu Expressway at the Yankou Tunnel, and its endpoint links up with the Nanchuan-Liangjiang Expressway. The total length of the route is approximately 37.18 kilometers, designed for a speed of 100 kilometers per hour and constructed according to the standards of a dual carriageway highway with four lanes.