China's first sea-crossing highway-rail dual-purpose bridge links up!

The world's most difficult cross-strait highway and rail dual-purpose bridge is being built. China's first cross-strait highway and rail dual-purpose bridge, the Pingtan Strait highway and rail bridge, was completed in the morning of September 25.

The Pingtan Bridge, which was built in November 2013, is a controllable project of Fuzhou-Pingtan Railway. Its total length is 16.34 kilometers. The bridge starts in Songxia Town, Changle City, Fujian Province, and goes to sea from the exit of Haimen Tunnel. It passes through Renyu Island, Changyu Island, Xiaolian Island and Dalian Island in turn. It crosses Yuanhong Channel, Guyumen Channel, Xiaolian Island Channel and Beidongkou Channel in turn, and Pingtan Island, Suao Town. The upper part of the bridge is designed as a six-lane Expressway with a speed of 100 kilometers per hour, and the lower part is designed as a double-track I-grade railway with a speed of 200 kilometers per hour.

The Pingtan Bridge is located at the northern mouth of the Haitan Strait, adjacent to the Taiwan Strait. It belongs to the typical marine monsoon climate. In addition, the confrontation between the Taiwan Island and the Wuyi Mountains forms a unique narrow pipe effect, which makes the Haitan Strait known as one of the three major wind vents in the world, along with the Cape of Good Hope at the southern end of Africa and Bermuda in the North Atlantic.

Compared with the bridges built in the Inland river, Bohai Sea, Yellow Sea, East China Sea and South China Sea, Pingtan Strait Railway Bridge has the characteristics of strong wind, high wave, large tidal range, deep water and rapid current. Its construction conditions are more harsh and complex, construction is more difficult and safety risk is higher. Among them, the construction of N03 pier of Yuanhong Channel Bridge is the most difficult, and the drilling of the foundation stone is very difficult, which takes more than two years.

In view of the harsh construction conditions, the design concept of Pingtan Strait Railway Bridge is to minimize the workload of on-site construction. In the design of cable-stayed bridge of waterway bridge, the design idea of full welding of two large segments and integral hoisting on site is adopted. In the design of simply supported steel truss girder, the whole hole welding and field whole hole hoisting are adopted.

As we all know, the steel used in bridge engineering of Hong Kong-Zhuhai-Macao Bridge is 425,000 tons, and that of Shanghai-Tong Yangtze River Railway Bridge is 480,000 tons. The Pingtan Strait Bridge, which shares 853,000 tons of steel, has the largest volume in China, "equivalent to the volume of the four bridges on the Yangtze River".

According to technicians of China Railway Bridge Bureau, Pingtan Strait Railway-highway Bridge is the first cross-strait Highway-Railway Bridge in China; 4.9 metre super-large diameter bored pile foundation is used in bridge foundation for the first time; two-section fully welded steel truss beam structure is used in steel truss cable-stayed bridge for the first time; 80 metre and 88 metre span whole hole is used for the first time. Fully welded steel truss composite beam structure.

The construction of Pingtan Strait Railway-highway Bridge has successfully solved the difficult problems of bridge construction under the harsh and complex marine environment, accumulated the experience of design, construction and construction management, and formed a complete set of technology for the construction of Highway-Railway Bridge in complex sea area, which has important reference significance for similar bridge projects in the future.