“Five, four, three, two, one, rotate.” At 1:35 AM on August 23, with the command from the on-site commander, the two 54-meter-long girders of the Lanzhou-Xinjiang Railway overpass, a control project on the Urumqi West Station to Wubei Station connecting line undertaken by the 4th Company of the 15th Bureau, began to rotate. After a 50-minute “air turn”, the two continuous girders safely and smoothly rotated clockwise by 35 and 40 degrees, successfully crossing the Lanzhou-Xinjiang Railway. The two T-structures were precisely docked and smoothly closed, achieving the expected milestone and creating conditions for the opening of the Urumqi West-Urumqi North connecting line by the end of this year, accumulating valuable experience for similar bridge construction in desert areas.

　　It is understood that the Urumqi West to Urumqi North connecting line project has a total length of 25.433 kilometers. It is an important part of the Urumqi railway hub construction and the only route connecting the Urumqi-Jiang line, the Northern Xinjiang branch line, and the main Lanzhou-Xinjiang railway corridor.

　　The Lanzhou-Xinjiang Railway overpass has a total length of 2404.07 meters. At DzK10+458.89-DzK10+596.31, it crosses the existing Lanzhou-Xinjiang line at a 50-degree angle. The superstructure is a single-track prestressed concrete continuous girder, and the substructure consists of round-ended piers. To ensure the operational safety of the existing line, reduce the impact on existing line operations during construction, and ensure construction progress, the continuous girder section adopts rotational construction. That is, at piers 24# and 25#, cantilever segments are cast parallel to the existing line using form travelers, forming two 54-meter-long girders, each T-structure weighing 1948 tons.

　　“The principle of bridge rotation is like pushing a millstone: a turntable is installed on the cap, and jacks are used to push the bridge to rotate. The advantages of this parallel construction and rotation are that it effectively avoids the long interruption of existing line operations caused by traditional construction methods, greatly speeds up construction progress, and improves construction safety,” introduced project manager Wang Xiaowei.

　　Unlike single T-structure rotation, the Lanzhou-Xinjiang Railway overpass involves dual T-structure rotation. If both T-structures start rotating simultaneously and reach the remaining 8 degrees, there will be a collision. The technical staff repeatedly simulated the dynamic rotation path and controlled the initial rotation angle difference, effectively avoiding collision between the two T-structures during rotation and achieving staggered arrival.

　　The rotational construction adopted a safe and reasonable spherical hinge installation scheme, effectively controlling safety risks such as overturning during rotation caused by eccentricity of the curved girder. The so-called pier-bottom rotation involves installing spherical hinges, turntables, and other equipment at the pier bottom to support the 1948-ton, 15.7-meter-high pier column and continuous girder. Then, through jack traction, the substructure and girder are rotated simultaneously.

　　To ensure the smooth closure of the continuous girder, the project department conducted weighing tests on the girder and performed lifting counterweights at predetermined positions to ensure stable rotation of the girder. At the same time, a detailed rotational construction plan was formulated, and operators strictly followed operating procedures, conducting rigorous measurement and control at every construction step. Through the orderly coordination of on-site technical, operational, and precision measurement personnel, various difficulties before rotation were effectively resolved.

　　After 50 minutes of safe rotation, the two 54-meter-long T-structures were successfully closed. According to on-site technical personnel measurements, the work meets construction specifications.

　　Once the Urumqi West to Urumqi North connecting line project is completed, it will better utilize the freight capacity of the Urumqi-Zhundong line and the Lanzhou-Xinjiang line, break the transportation bottleneck of the Urumqi railway hub, and streamline freight channels. It is of great significance for meeting the freight demand of regions along the “Belt and Road”, ensuring the normal increase of China-Europe freight trains, and especially for smoothing foreign trade logistics between the central and eastern regions and Central and Western Asia.