On December 26, the Chaoma Railway Section 3 project undertaken by China Railway No. 4 Engineering Group reached a major milestone: the main tower of the auxiliary channel bridge of the Ma'anshan road-rail Yangtze River Bridge was successfully capped. The A-shaped main tower, like two giant columns soaring and converging, stands majestically over the Wanjiang River. As an important milestone in the Group's bridge construction, the smooth capping of the main tower has laid a solid foundation for subsequent steel girder erection and ballastless track construction.

The auxiliary channel bridge of the Ma'anshan road-rail Yangtze River Bridge is a controlling project of the Chaoma intercity railway and a key livelihood project for implementing the Yangtze River Economic Belt and Yangtze River Delta integration development strategies. With a main span of 392 meters and a tower height of 170 meters, it is a road-rail river crossing integrating a high-speed intercity railway and an urban expressway, and is currently the world's longest-span ballastless track three-cable-plane cable-stayed bridge.

The bridge has a total length of 844 meters. The main bridge adopts a two-level layout and is built to the standard of "four railway tracks plus a six-lane urban expressway," featuring a large project scale, high technological content, great construction difficulty and a complex construction environment. The lower structure of the main tower at Pier F4, which was capped this time, consists of 30 bored piles with a diameter of 2.8 m; the pile cap is dumbbell-shaped; the main tower is an A-shaped tower with a height of 170 m, composed of upper, middle and lower tower columns, the tower top and the lower crossbeam. The cable-stayed anchorage zone of the upper tower column has a single-box three-cell cross-section and was constructed in 32 segments.

In terms of both construction difficulty and techniques, the project presented a completely new challenge to the project team. To ensure rapid progress of the project, the project department organized several special technical meetings on main tower construction and continuously optimized construction techniques. The project team rose to the challenge and took the initiative, successively solving many problems such as mass concrete construction, the large-inclination climbing formwork system for the tower columns, rapid standardized construction of the middle tower column, high-altitude installation of steel anchor beams, rapid positioning and surveying of steel anchor beam cable ducts, and safety control of high-altitude operations, while ensuring the orderly progress of various cross-operations. During the process, the leadership team carried out shift supervision, Party members and cadres took the lead by example, and the team stayed focused on its goals, organized scientifically and advanced construction with high quality. At the same time, in view of the large inclination of the main tower, when designing the climbing formwork, the project department scientifically divided the formwork into blocks according to the changing characteristics of the main tower structure to facilitate on-site cutting. During construction, strict requirements were imposed on formwork surface treatment and the use of release agents to maximize formwork flatness. To address construction difficulties such as the high strength and high crack resistance of the main tower concrete, an intelligent curing system consisting of a fog-making machine, a closed curtain system (for cast and curing layers) and a control system was used to cure the concrete. This series of measures greatly improved the appearance quality of the main tower concrete and ensured the smooth completion of the main tower capping.

"The main tower of the auxiliary channel bridge of the Ma'anshan road-rail Yangtze River Bridge is an A-shaped tower, with tower columns inclined inward. At some important parts, such as the junction between the lower crossbeam and the main tower, the connecting section of the upper tower column and the cable-stayed anchorage zone, the cross-section changes greatly and the reinforcement structure is complex, making precise positioning of multiple sets of steel anchor beams in a single segment very difficult. Facing new technologies and new challenges, all participating employees did not wait or rely on others, but kept responsibility in their hearts and took initiative as a matter of course, focused their efforts, carried out all work in a solid and detailed manner, and sought progress while maintaining stability, achieving new breakthroughs in the construction of a super-long-span bridge," introduced Gao Zhijun, the project chief engineer.

As a direct connecting line between Hefei and Ma'anshan, the Chaoma intercity railway will become an important part of Hefei's "one-hour commuting circle" after completion. It is also a new high-speed rail corridor from Anhui to Shanghai and other Yangtze River Delta cities, and is of great significance for further improving the regional high-speed railway network layout, enhancing corridor transport capacity, accelerating the development of the Wanjiang urban belt, and building Anhui's "Hangjiahu" and a "Yangtze River Delta on rails."