In the early hours of May 16, after 40 hours of continuous construction, the first large-volume in-water pile cap concrete for the Lanjiang Grand Bridge on the Jinhua-Jiande High-Speed Railway, built by China Railway No. 3 Engineering Group, was successfully poured. This is the first in-water pile cap pour on the entire line, laying a solid foundation for subsequent construction.

Distant view of the Lanjiang Grand Bridge on the Jinhua-Jiande High-Speed Railway

The Lanjiang Grand Bridge is a key controlling project of the Jinhua-Jiande High-Speed Railway. The bridge has a total length of 6.5 kilometers and crosses the Lanjiang River using a (72+2×136+72) m continuous girder + (100+200+100) m low-pylon cable-stayed bridge + 2×88 m T-frame + (72+136+72) m continuous girder. The first large-volume in-water pile cap concrete construction was located at Pier 97 of the Lanjiang Grand Bridge, where the maximum water depth is nearly 8 meters. The pile cap is designed to be 31.2 m long, 19 m wide and 5.6 m high, with a designed reinforcement quantity of 384.4 t and a designed concrete volume of 2,915.4 m³, making it a large-volume concrete pour. First in-water pile cap pour on the entire Jinhua-Jiande High-Speed Railway

First in-water pile cap pour on the entire Jinhua-Jiande High-Speed Railway

To ensure the smooth pouring of the pile cap, the project department planned ahead and organized scientifically, convening special construction meetings and technical disclosure meetings. During construction, the project department formed professional construction teams, strengthened on-site dynamic management, strictly implemented safety, quality and technical disclosures, optimized construction资源配置, and assigned technical and testing personnel to monitor on site. In accordance with standardized construction requirements, concrete was poured, vibrated and discharged in layers; embedded temperature-measuring elements were monitored in real time; and a water-injection cooling circulation system was installed to prevent structural cracks caused by hydration heat, ensuring smooth concrete pouring.

Because the pile cap construction site is inside a steel cofferdam, the working area is limited; the pile cap concrete volume is large and the pouring time is long, and the hydration heat temperature of the concrete is too high, seriously threatening construction safety and project quality. "In light of the project characteristics, we adopted an integral layered continuous pouring process and took measures such as using blowers for ventilation and five-layer cooling pipe circulating water for temperature reduction, ensuring safety and quality at the construction site," introduced Wei Xiaobing, project manager of the Jinhua-Jiande High-Speed Railway project of China Railway No. 3 Engineering Group. First in-water pile cap pour completed on the entire Jinhua-Jiande High-Speed Railway

First in-water pile cap pour completed on the entire Jinhua-Jiande High-Speed Railway

It is understood that the successful completion of the first in-water pile cap pour of the bridge marks the transition of the main bridge construction to the above-water construction stage and has accumulated valuable experience for large-volume concrete pouring of in-water pile caps. The Jinhua-Jiande High-Speed Railway is part of the "Huangshan-Jinhua" railway corridor in the national rapid railway network. After the line is completed, the railway, only more than 60 kilometers long, will connect four high-speed railways and become an important hub and node in the national southeast high-speed rail network. By then, it will take only 15 minutes from Lanxi to Jiande and only 1 hour from Jinhua to Huangshan.