The steel frame for the factory building in which HS2 will cast the concrete tunnel lining segments for its Chiltern tunnels has been completed at the project’s Chalfont Lane site near the M25 motorway.
The factory will allow HS2’s main works contractor, Align JV (a joint venture made up of three companies: Bouygues Travaux Publics, Sir Robert McAlpine, and VolkerFitzpatrick), to cast all the tunnel segments on site and avoid putting extra HGVs onto local roads.
HS2’s two giant tunnelling machines – named Florence and Cecilia – are due to launch next year. The 170-metre-long, 2,200 tonne machines will spend more than three years underground, moving at a speed of 15.6 metres a day, and use 112,000 concrete segments to line the tunnels.
A second precast plant will be used to cast sections for the nearby Colne Valley viaduct. Once all of the HS2 construction work is complete, the pre-cast plants will be disassembled and the whole site will be landscaped, usimg material excavated from the tunnels, and trees planted in order to blend it in with the surrounding countryside.
The factory buildings, which will include a general warehouse, workshops and soil treatment plant as well as the two pre-cast factories, will use 2,400 tonnes of steel, all of which is being manufactured and supplied by specialist steel fabricator Caunton Engineering from its base near Moregreen, Nottinghamshire.
Mark Clapp, HS2’s senior project manager for this section of the route (known as C1), said: “The pre-cast plant will play a crucial role in delivering the Chiltern tunnels. By casting all 112,000 segments on site, we can significantly reduce the number of HGVs on local roads, reducing disruption for the local community.
“I’d like to thank everyone at Align and especially Caunton for their hard work in making it happen.
“Caunton’s involvement shows how HS2 is delivering for companies right across Britain, creating jobs and helping the economy recover from the pandemic.”
Align project director Daniel Altier added: “Caunton Engineering is delivering the steel for all the structural buildings at our south portal site, 15 in total. This includes two tunnel pre-cast factories, the tunnel workshop and warehouse, and the viaduct precast factory.
“In selecting Caunton, we opted for a company that can deliver a high-quality product and value for money. The selection of key suppliers such as Caunton is essential in order that we can deliver the project on time and on budget.”
Caunton, which employs 250 people in the East Midlands, is one of the UK’s leading fully automated structural steelwork contractors and a leader in ‘Just in Time’ manufacturing. The family-owned firm, which has 50 years of experience in the sector, also delivered steelwork for the iconic new Museum of Liverpool.
Matthew Shimwell, Caunton’s managing director, commented: “We are thrilled to be working with the Align team in helping to deliver this key part of infrastructure work. The project is an excellent example of how early engagement with the supply chain brings real value to a project.
“This collaborative approach has helped to optimise the design of the buildings to more fully benefit from an informed DFMA approach (Design For Manufacture and Assembly).
“We wish the project team every success as it enters the next key stage in delivering this prestigious project.”