China's First Sea-crossing Railroad Bridge Ready for Above-water Construction

Design sketch of the sea-crossing high-speed railway bridge [Photo/China Railway Construction Corporation Limited]

Another main pier of the Fuzhou-Xiamen sea-crossing high-speed railway bridge was installed on March 25. With that, both the two main piers of the bridge had been installed, offering strong support for the transition from under to above-water construction.

On completion it will be the first sea-crossing high-speed cable-stayed railway bridge with composite beams in China and in the world. It will also be the fourth longest sea-crossing railroad bridge in the world.

According to Yan Aiguo, chief engineer of China Railway Siyuan Survey and Design Group, the bridge will have a projected speed of up to 350 kilometers per hour.

The bridge was designed by China Railway Siyuan Survey and Design Group Co., Ltd. which is affiliated to China Railway Construction Corporation Limited (CRCC).

The high-speed railway starts from Fuzhou and terminates in Xiamen and Zhangzhou, a total distance of 277 kilometers.

To build the bridge safely, efficiently and economically, steel suspension boxes were used as a stable platform.

A single steel suspension box weights 517.7 tons, is three-floor high and has an area equal to two basketball courts. It is basically a huge box whose bottom is connected with and fixed to the pile foundation in the water.

A man-made island is then fashioned by pouring concrete into the box and pumping out the water, which makes it easier to carry out the construction.

The marine environment, including strong wind, rough water, rapids, large tide scope, high salinity and high humidity, creates great challenges to the accuracy of construction and high-speed train operation.

For instance, the bridge line must be guaranteed to within millimeters even in the face of those difficulties, Yan said.

In addition, strong wind and huge waves may impact safe driving and the comfort of passengers, which is also a serious problem.

The bridge is a steel-concrete stable-stayed combination structure, a unitary steel frame without supports that must resist corrosion by the marine atmosphere.

"The construction of the bridge started on Sept 30, 2017 and is expected to be completed by the end of 2020," Yan said.

The bridge will be a start of a new era for the world's high-speed sea-crossing railroad bridges and will promote the development of China's technology in building large-span high-speed railways and sea-crossing structures.

Travel time from Fuzhou to Xiamen will be reduced from two hours to one, and the Xiamen-Zhangzhou-Quanzhou Metropolitan Area and the Fuzhou Metropolitan Area will be linked, which will benefit the two areas as they develop as one region.

(Executive editor: Hao Wen)