On July 30, reporters visited the construction site of the Wenzhou Oujiang Beikou Bridge, where a busy scene unfolded as the project proceeded in an orderly manner. The first main girder of the Wenzhou Oujiang Beikou Bridge has now been successfully erected, marking a breakthrough in the project's progress.

It is understood that the Wenzhou Oujiang Beikou Bridge is the final section of the Yongguan Expressway, a major artery along China's coast. The bridge has a total length of 7.913 kilometers and is scheduled to be closed and completed by the end of the year.

"This project is another world-class bridge project launched in Zhejiang Province after the Hangzhou Bay Bridge and the Zhoushan Cross-Sea Bridges," said Xiang Weisheng, Party Secretary and Director of the Wenzhou Municipal Transport Bureau, in an interview with reporters. Once completed, the final 7.9 kilometers of the 378-kilometer Zhejiang coastal expressway (G1523 Zhejiang section) will be connected, and the Yongguan Expressway will be open to traffic along its entire route.

Completing a section of the national highway network

Advancing Zhejiang's development as a demonstration zone for common prosperity

Looking across the land of Ouyue, once marked by long mountains and treacherous waters, transportation networks now crisscross the region with impressive momentum.

Xiang Weisheng told reporters that since the 13th Five-Year Plan period, Wenzhou has invested more than 200 billion yuan in comprehensive transportation, and the city's total expressway mileage has risen from third from the bottom in the province to second, achieving a qualitative leap in sea, land, air and rail transport.

According to Xiang Weisheng, under the 14th Five-Year Plan, Wenzhou will make every effort to advance key comprehensive transportation projects, comprehensively improve the integrated development of corridors, hubs and networks, and basically build itself into a national comprehensive transportation hub.

Xiang Weisheng said that the Wenzhou Oujiang Beikou Bridge, a major national transportation project to be completed during the 14th Five-Year Plan period, is of great significance for completing a section of the national highway network, improving the capacity of the eastern coastal highway transport corridor, further strengthening links among the Yangtze River Delta, the west coast of the Taiwan Strait and the Pearl River Delta, and advancing Zhejiang's development as a demonstration zone for common prosperity.

"In the past, people in Yueqing, Wenzhou, who wanted to cross the river to Wenzhou Airport had to detour via the Wenzhou Bridge upstream on the Oujiang River, which took about an hour and a half," Pan Ji, general manager of Wenzhou Oujiangkou Bridge Company, told reporters. Once the bridge is completed, the trip from Yueqing to the airport will be shortened from an hour and a half to 30 minutes, saving an hour.

Grand scale and unique structure

Featuring three world-first technologies

"The first main girder is 28.5 meters long, 41.8 meters wide and 12.5 meters high. It traveled more than 890 kilometers by sea from Nantong, Jiangsu, to the bridge site in Wenzhou, Zhejiang, for hoisting and installation," said Zheng Fengli, deputy general manager and chief engineer of Wenzhou Communications Development Group.

Zheng Fengli noted that the Wenzhou Oujiang Beikou Bridge is the world's first three-tower, four-span double-deck steel truss suspension bridge, with the Yongguan Expressway on the upper deck and National Highway G228 on the lower deck. "The bridge is 7.9 kilometers long, including a 2,090-meter main span across the Oujiang River. The project is one of the most technically difficult and constructionally complex bridges in China and the world."

Pan Ji said the project is grand in scale, complex in technology and novel and unique in structure, boasting three "world firsts": first, the first three-tower, four-span double-deck steel truss suspension bridge structure; second, the first use of a rigid concrete middle tower in a multi-tower continuous-span suspension bridge system; and third, the first construction of a super-large caisson foundation in deep soft soil strata at a strong tidal estuary. "This provides new ideas and valuable construction experience for future infrastructure in cross-sea corridors."

Resource-saving and eco-friendly

"Two bridges built as one" upholds the concept of green development

As one of the first green highway demonstration projects of the Ministry of Transport, the Oujiang Beikou Bridge incorporates the green concepts of "resource conservation and ecological protection" into its construction. Through the innovative design of building the expressway and the ordinary national highway as "two bridges in one," the bridge achieves intensive development of corridor and shoreline resources, saving about 193 mu of land.

According to Zheng Fengli, the project adopts a co-linear design with a double-deck deck system, and the main bridge is a steel truss structure with a double-deck deck. "Compared with concrete bridges, steel structures are lighter, have uniform materials and stable quality, can be factory-manufactured and assembled on site, and are highly recyclable, making them more energy-efficient and environmentally friendly."

Zheng Fengli told reporters that the Oujiang Beikou Bridge vigorously promotes the use of steel structures, with more than 300,000 tons of steel used for the entire bridge. The main girder is entirely of steel structure, effectively improving the quality of the bridge construction and reflecting the project's full implementation of the green development concept.

To do a good job, one must first sharpen one's tools. Through measures such as developing the world's first 1,000-ton-class split cable-mounted crane, China's first welding robot for deep-groove saddle installation on a long-span suspension bridge, and an intelligent monitoring platform, the Oujiang Beikou Bridge has greatly improved construction efficiency.

"The heaviest segment of the main girder weighs 813 tons, and existing domestic cable-mounted cranes simply cannot meet the lifting requirements of a single unit," Pan Ji told reporters. To solve this problem, the project innovatively developed China's first 1,000-ton-class cable-mounted crane, equipped with human-machine interfaces, sensor technology and communication technology, controlling installation precision errors to within 5 millimeters and ensuring safe and efficient construction.

In this regard, a number of industry experts said the project's intelligent production and digital transformation have achieved notable results, effectively improving project quality and ensuring project safety.