In a UK first, a giant cantilever structure has been used to build part of HS2’s River Tame West Viaducts.
The specialist process was used to build the first span of the 472-metre structure, a single-track viaduct, in the West Midlands.
The River Tame West Viaducts carry three rail tracks in total, comprising one single-track and one double-track viaduct. They are situated at the northern tip of the Delta Junction, the triangular section of railway connecting London, Birmingham and the North.
They are supported by 20 piers, work on which began in 2023. The first spans of the three track section were completed earlier this year. The initial phase involved placing segments onto two 42-metre truss beams, moving them into place with a skidding trolley, and securing them by post-tensioning techniques.
The giant cantilever has since been built using a 22-metre-high mast and a 14-metre-high swivel crane.
The crane lifts and installs one concrete segment into place at a time until each 45-metre span length is completed. The permanent post-tensioning tendons are stressed to allow the removal of the temporary cable stays, leaving the permanent structure in place. The process is repeated between each pier until all of the spans are completed.
Sam Hinkley, HS2’s Lead Senior Project Manager for Delta Junction said: “This is a fantastic UK-first for HS2, signifying another proud moment for everyone working on the project.
“It has only been possible through the collaborative and innovative approach with our designers, civils contractor and wider supply chain, who are delivering this huge feat of engineering.”
A team of 40 people are currently working to move 2500 concrete blocks into place using this technique, with all deck segments due to be in place by August 2026.
The same processes will be used to build nine viaducts in the Delta Junction.
The River Tame West Viaducts will cross the river near Water Orton and join the Curdworth Box, which will take high-speed trains over the existing line between Birmingham and Derby.
Image and video credit: HS2
