On January 12, with the precise positioning of the final arch rib closure segment, the arch ribs of the 168-meter tied-arch continuous girder spanning National Highway G329 of the Dingyuan No. 2 Grand Bridge on the Hefei–Xinxiang High-Speed Railway—the largest-span tied-arch continuous girder under construction in Anhui Province, built by China Railway 24th Bureau Group—were successfully closed, marking the full completion of the continuous girder and laying a solid foundation for subsequent ballastless track construction.

 The arch ribs of the 168-meter tied-arch continuous girder were successfully closed.

　　The tied-arch continuous girder of the Dingyuan No. 2 Grand Bridge on the Hefei–Xinxiang High-Speed Railway is a controlling node of the Anhui section of the line. It spans National Highway G329, with a total length of 240.4 meters and a maximum span of 168 meters. The main bridge of the tied arch adopts the construction method of erecting the girder first and then the arch. The arch ribs use a dumbbell-shaped concrete-filled steel tube section, with nine cross braces arranged between the two arch ribs. Due to the large span of the main arch, it could not be fabricated in one piece. Based on the force characteristics of the main arch, the designers carried out analysis and calculation and divided each arch rib into 15 segments for fabrication and on-site splicing. At the same time, during the prefabrication of the steel tubes, the shrinkage of the segmented joint welds was fully taken into account, and the assembly process design was optimized to ensure accurate dimensions of the assembled components, guarantee welding quality, and reduce welding deformation. To ensure the safe and precise splicing of each arch rib segment in the air, the project department continuously optimized the hoisting scheme and refined the installation steps, strictly controlling the construction process in terms of quality, safety, and precision. Based on the alignment of the main arch and the segment division, the project technical personnel calculated the coordinates and elevations of each splicing point and used a total station for precise positioning. They adopted measures such as standardized prefabricated supports, safety ladders, operating platforms, windbreak frames, and stabilizing brackets for arch rib positioning, ensuring the project was completed to a high standard on the first attempt.

　　During the arch rib installation, two 130-ton truck cranes lifted the segments simultaneously from the arch springings at both ends toward the midspan onto the supports, and installation and welding were carried out symmetrically. After the previous arch rib segment was welded into an integral whole with the subsequent segment, the next segment was hoisted, and this process continued in sequence until splicing reached the closure segment at the highest point. Based on real-time monitoring data, the project technical personnel adjusted the height difference and spacing of the arch rib closure opening, and according to the results of continuous monitoring data, carried out matching cuts on the closure segment arch rib, successfully achieving "zero-error" precise closure.

　　After the Hefei–Xinxiang High-Speed Railway is completed and opened to traffic, it will further improve the layout of the national high-speed railway network, strengthen the economic integration of the Wanjiang City Belt and the urban agglomeration in the middle reaches of the Yangtze River with coastal areas such as the Shandong Peninsula and Liaodong Peninsula, and is of great significance for building the Huaihe River Ecological Economic Belt, promoting the coordinated economic development of the regions along the line, and serving the high-quality development of the Yangtze River Economic Belt and the integrated development of the Yangtze River Delta.