NW China's largest high-speed rail beam rotation completed

The steel box girder for the newly constructed Xiyan (Xi'an-Yan’an) High-speed Railway Xi'an Hub Connection Line was smoothly rotated over the Daxi (Datong-Xi’an) High-speed Railway at Xi'an North Station in Shaanxi province on December 6.

A significant milestone was achieved with the largest and first continuous steel box girder rotation over existing high-speed railway lines at a major high-speed railway hub station in Northwest China. It highlights the rapid progress of the Xiyan High-speed Railway, linking Xi'an, the capital of Shaanxi province, with Yan'an, a historic city known for its abundant energy resources in northern Shaanxi. Navigating over the Daxi High-speed Railway poses a major challenge in this project. The task involves precisely aligning and rotating a 97.9-meter-long and over 600-ton steel box girder across the existing line, while maintaining a horizontal slope within 2.5 percent.

“To ensure smooth progress, we approved eight hours of construction time across two window periods, and replaced the original porcelain insulators on the Daxi High-speed Railway with composite insulators within the design scope, minimizing the impact of induced electricity. At the same time, we coordinated with engineering, electrical and other units on site to protect existing equipment and ensure construction safety,” said Kang Zhongwei, deputy commander of the Second Engineering Command Center of Xi'an Railway Bureau.

Due to the limited number of cases of such hub stations crossing existing lines for rotation, a project team composed of Xi'an Railway Bureau, China Railway First Group, and China Railway First Survey and Design Institute Group repeatedly simulated and rehearsed the construction measures based on expert demonstration of the special construction plan to ensure foolproof operation.

The project team has set up seven temporary support systems to transport and position the steel beams, rotating them in sections and welding them into place. A traction system with 12 steel strands and an automatic continuous jack is used to move the prefabricated steel box beam 22.5° to the right at a speed of 12 meters per hour. After more than  three hours of continuous work, the beam was properly positioned.

“We use Beidou GNSS high-precision satellite measurement technology and an information-based digital platform to monitor the spatial attitude of the beam in real time, ensuring the safety and reliability of structural rotation construction,” said Zheng Jiaxing, head of the Xiyan High speed Railway Bridge Specialty at China Railway First Survey and Design Institute Group.

The Xiyan High-speed Railway, the first in northern Shaanxi's old revolutionary area, is a key part of the Baotou (Yinchuan)–Hainan high-speed rail corridor. Spanning 299.8 kilometers, it features a double track and a design speed of 350 km/h. Once operational, the travel time from Xi'an to Yan'an will be reduced from 2.5 hours to an hour.