On July 28, at the construction site of the Cangrong Xunjiang Bridge, invested by Guangxi Communications Group and constructed by CCCC Second Harbor Engineering Co., Ltd., tugboats pulled the pilot cables, hauling them from the central tower to the north and south side towers respectively, marking the first time the three main towers have "joined hands."

The photo shows the construction site. Image courtesy of CCCC Second Harbor Engineering Co., Ltd.

　　The main line of the Cangrong Expressway is 105.6 kilometers long, designed as a dual-direction, four-lane road with a driving speed of 120 kilometers per hour. Among them, the Cangrong Xunjiang Bridge is currently the world's largest-span single-column three-tower spatial cable suspension bridge and China's first three-tower spatial cable suspension bridge with a span exceeding 500 meters. The bridge has a total length of 1,688 meters, with both main spans measuring 520 meters. All three main towers adopt a central single-column design, with the central tower standing 108.9 meters tall and the side towers 108.8 meters tall. The bridge's traction system construction, catwalk erection, main cable erection, and main girder erection and other key processes are all over-water operations characterized by high construction difficulty and high risk.

　　The traction system is an important component of the superstructure construction, mainly used for erecting the catwalk and main cables. The construction of the traction system first relies on the pilot cable to be completed. As a key construction process for the bridge superstructure, pilot cable crossing the river is usually carried out by means such as boat towing or drone deployment.

　　Because the Cangrong Xunjiang Bridge is located in the open waters of the Xunjiang River—the middle reaches of the main stream of the Xijiang River in the Pearl River Basin—and lies within an aviation control zone, construction organization and coordination are difficult and safety risks are high. After comparing multiple schemes and expert demonstration, the project team ultimately adopted the boat-towing scheme, which offers strong safety and high construction efficiency.

　　On that day, under the full escort of the maritime department, the tugboat pulled the pilot cable from the central tower across the river to near the south tower, where it was connected to the end of a steel wire rope lowered from the top of the south tower and then unhooked. After about 2 hours, a single pilot cable with a length of 900 meters successfully crossed the 500-meter-wide water area of the south main span. With the cooperation of the winches atop the central and south towers, the pilot cable was lifted to a height of more than 40 meters above the river surface to meet the navigable clearance requirements, thus completing the pilot cable erection for the south main span. Subsequently, the project team used the same method to pull the pilot cable across the river for the north main span.

　　The successful crossing of the pilot cable created the prerequisite for the aerial catwalk erection of the Cangrong Xunjiang Bridge and facilitates the subsequent main cable and steel box girder erection and other main superstructure construction. Next, the project team will use the pilot cable as a basis to carry out the traction system construction between the main towers and the anchors, ensuring the project is completed and opened to traffic in 2025.