On October 8, the reporter learned from CCCC Second Harbor Engineering Co., Ltd. that with the successful welding of the last steel box girder segment, the Nanjing Xianxin Road Yangtze River Bridge was successfully closed recently. The bridge adopts a double-tower single-span suspension bridge with a main span of 1,760 meters; once completed, it will become the suspension bridge with the largest span in China and the third largest in the world.

The Xianxin Road river-crossing channel is located on the northeast side of Nanjing, with a total length of about 13.17 kilometers. The Xianxin Road Yangtze River Bridge is the key control project of the channel. Xianxin Road passes through a chemical industrial park, and its river-crossing channel will become Nanjing's first river-crossing channel permitting the passage of hazardous chemical vehicles.

"The main girder of the bridge adopts the steel box girder form, divided into 6 types and 97 segments, which are lifted symmetrically and synchronously in sequence from mid-span toward the main towers by 2 sets of 500-ton cable-mounted cranes. The work area is divided into shallow-water and deep-water zones," said Zhang Guohao, project manager of the Xianxin Road project of CCCC Second Harbor Engineering. The shallow-water zone has a total of 36 segments, with the heaviest box girder weighing about 333 tons, equivalent to the weight of more than 200 cars; the deep-water zone has a total of 61 segments, with the heaviest box girder weighing about 270 tons.

Xiao Haizhu, chief engineer of China Railway Major Bridge Reconnaissance & Design Institute, introduced that the Nanjing Xianxin Road Yangtze River Bridge is a long-span steel box girder bridge whose main girder is relatively narrow in width and light in structural dead weight, and whose span-to-width ratio reaches 56:1; the bridge has a relatively low natural frequency of vibration and is relatively sensitive to wind loads. To clarify its vortex-induced vibration mechanism and vibration suppression measures, the design team, together with universities, carried out scientific research and proposed a novel vortex-induced vibration suppression structure and design method for long-span bridges, providing a strong guarantee for the aerodynamic stability and safety of the bridge.

Guo Jiajia, chief engineer of the Xianxin Road project of CCCC Second Harbor Engineering, introduced that, in light of the characteristics and difficulties of the project, the project team developed 2,100 MPa main cable steel wire strands for the first time, effectively reducing costs and reducing the dead weight of the superstructure; for the first time, it carried out research on fire protection technology for suspension bridge main cables, obtained comprehensive control parameters for the fire resistance performance of super-long-span suspension bridges, and developed a composite fire-resistant protection system and a complete set of technologies and products for the fire resistance of suspension bridge main cables and nodes.

It is reported that the bridge is constructed by the Nanjing Public Engineering Construction Center, with CCCC Second Harbor Engineering participating in construction and China Railway Major Bridge Reconnaissance & Design Institute undertaking survey and design. The completion of the project will be a powerful measure to implement national strategies such as the integrated development of the Yangtze River Delta and the development of the Yangtze River Economic Belt, and will help ease traffic pressure across the river and enhance the convenience of connections between Nanjing Jiangbei and Longpao and the Xianlin sub-city and the main city. By then, the drive from Qixia Avenue to Jiangbei Avenue will be shortened from the original 1 hour to 10 minutes.