At 8:08 a.m. on June 3

After 16 hours of intensive construction over two nights

constructed by China Railway 14th Bureau Group

the Beijing-Tangshan Intercity Railway

Tongji Road Steel Arch Bridge successfully completed its incremental launching

marking the completion of China's first railway

sparse-suspender truss-type steel arch bridge

with construction error of less than 5 millimeters

laying a solid foundation for the smooth opening of the entire line

The Beijing-Tangshan Intercity Railway is a rapid transit corridor from Beijing to Tangshan. The project is being built in two sections; the first section, the Tangshan-Yanjiao segment, opened to traffic on December 30, 2022. The Beijing underground section connecting the Sub-center Station and Yanjiao Station has a total length of 2.4 kilometers, starting from the Beijing Municipal Administrative Center Station and connecting with the completed Beijing-Tangshan Intercity Railway via a subgrade section.

New design pioneers a new structure: saving 85% of steel consumption

The Tongji Road Steel Arch Bridge of the Beijing-Tangshan Intercity Railway features a double-V suspender structure with a simple and transparent appearance and light, compact members, embodying the meaning of "victory" and "welcome." The overall shape resembles two pairs of seagulls flying with spread wings, echoing the "Beijing Sail" of the nearby Beijing Municipal Administrative Center Station hub.

According to Sun Lijun, project manager of the Beijing-Tangshan Intercity Railway project of China Railway 14th Bureau Group, the Tongji Road Steel Arch Bridge has a total length of 75.75 meters and is the last bridge to be completed for the full line. The steel arch bridge adopts a brand-new lightweight design, with the bridge's dead weight reduced from 4,600 tons to 700 tons and steel consumption per linear meter of only 11.2 tons, lower than similar railway steel arches or steel truss girders, greatly saving steel consumption.

New scheme boosts new speed: reducing road closure time by 30 days

The steel arch bridge is adjacent to the Beijing-Harbin Railway and the Tongyan Expressway, and spans over Tongji Road, a main road of the Municipal Administrative Center, with its closest point to the Beijing-Harbin Railway only 15 meters away. To minimize the impact on normal social traffic, the project team conducted dedicated research and multiple demonstrations, optimizing the full-scaffold cast-in-place concrete arch bridge into a fully welded steel arch bridge, and adopting a scheme of transverse shifting followed by longitudinal launching for the entire bridge. The steel arch bridge was installed using a "one bridge, two sites" construction mode, with the superstructure and substructure constructed simultaneously.

"While the substructure such as bridge pile foundations, pile caps and abutments was being constructed at the site, the superstructure steel bridge was simultaneously undergoing factory material cutting and component processing. The time for factory manufacturing and on-site assembly was shortened from the originally designed 168 days to 65 days, greatly improving construction efficiency," said Shao Lu, technical director of the Beijing-Tangshan Intercity Railway project of China Railway 14th Bureau Group. The original plan required 32 days of road closure; after optimizing the construction scheme, the launching construction was completed in only 16 hours.

New technology sets a new record: error within 5 millimeters

Before the launching of the steel arch bridge, the construction team used a large-scene laser scanner for digital measurement and conducted quality inspection based on the scanned point cloud data; through virtual pre-assembly, construction precision and quality were improved; through overall trial launching of the bridge, equipment was adjusted and the system safety of the support system and dragging system was verified.

During the launching operation, a dragging and sliding system integrating multiple functions such as transverse deviation correction, longitudinal launching and synchronous coordinated force was adopted to ensure smooth and stable launching and sliding. Through real-time monitoring and analysis of the bridge's launching posture and stress conditions, the transverse shifting and launching construction were guided, enabling the bridge to successfully cross Tongji Road and reach above the design position, with the deviation controlled within 5 millimeters.

In addition, the steel arch bridge introduced magnetic unattended video inspection equipment for the first time, making routine inspection and maintenance safer, simpler and more convenient, and achieving unmanned and intelligent inspection and maintenance of facilities.

After the Beijing underground section of the Beijing-Tangshan Intercity Railway is completed and opened to traffic, it will further strengthen connections within the Beijing-Tianjin-Hebei region. It is of great significance for relieving Beijing of non-capital functions, accelerating the building of a "Beijing-Tianjin-Hebei on Rails," driving economic and social development in areas along the line, enhancing the overall competitiveness of the region, and implementing the national strategy of coordinated development of the Beijing-Tianjin-Hebei region.