The largest span sea crossing bridge in China

On March 10, 2026, the Shuangyumen Extra Large Bridge, the second phase of the Ningbo Zhoushan Port Liuheng Bridge project, which is the largest span cross sea bridge in China, was successfully pulled across the sea by the first main cable benchmark strand. This marks the official entry of the bridge into the critical stage of main cable installation, laying a solid foundation for subsequent strand installation and cable clamp construction.

The Shuangyumen Grand Bridge is located in Zhoushan, Zhejiang Province, connecting Liuheng Island and Fodu Island. It is a key control project of the second phase of the Liuheng Highway Bridge. The main span of the bridge is 1768 meters, with an east main tower height of 246.3 meters, spanning the Shuangyumen Waterway. It is the largest span sea crossing bridge in China and the world's largest single span suspended steel box girder suspension bridge.

The bridge is equipped with 2 main cables, each consisting of 127 cable strands, each of which is made up of 127 high-strength steel wires with a diameter of 6.2 millimeters. The diameter of each cable strand ranks first among similar bridges in China. The benchmark cable strand of the No.1 main cable installed this time has a total length of approximately 3176 meters and a total weight of 97 tons, serving as the "baseline" and "lifeline" of the entire bridge's main cable system.

Faced with the complex and ever-changing marine construction environment, the project team has repeatedly optimized the construction plan and carried out technical breakthroughs, fully preparing for this high-altitude needle piercing operation. Before construction, comprehensive maintenance and debugging of traction equipment, repeated drills of cable transportation, lifting, traction and other processes, refined division of labor, strict control of parameters, comprehensive investigation of risks in offshore and high-altitude operations, and ensuring safe and smooth progress of installation.

The precision of benchmark cable installation is high

The benchmark cable installation requires extremely high precision, and the height difference between the left and right should be controlled within 10 millimeters. The project adopts the prefabricated parallel steel wire strand method for construction, and is pulled from the Liuheng Island to the Fodu Island through a double line reciprocating traction system. The cable strand lifting and lateral movement are completed in conjunction with anchorages, tower top gantries, and winches. At the same time, pre forming technology is used in the saddle area to pre organize the cable strands into quadrilaterals, greatly improving installation efficiency. During the construction period, a dedicated person will monitor the entire line to strictly prevent cable twisting, loose threads, and bulging, ensuring accurate alignment of the main cable and improving the safety and durability of the bridge structure. Keywords: Shuangyu Gate Extra Large Bridge, Cross Sea Bridge, Suspension Bridge

After the completion of the bridge, it will strongly support the development strategy of the national marine economy and the construction of a national level new area, further improve the external transportation system of the Zhoushan South Wing Islands, optimize the spatial layout of the Zhoushan Islands New Area, help build a modern marine industry base, and promote the coordinated development of the port areas and industries of Liuheng Island, Fodu Island, and Meishan Island, which has important strategic significance.Editor/Gong Ziwei