Crossing a busy road and several waterways, building HS2’s Colne Valley Viaduct has prompted some novel approaches, and for Construction News Ben Vogel explores how the Align JV is taking on the challenge.
image: for illustration only – HS2
… bridge faces tricky terrain, needing to….water features as well as the A412…
Ben Vogel for Construction News writes:
One of the trickiest construction and engineering aspects of the HS2 megaproject is the 3.4km-long Colne Valley Viaduct, whose main structure is scheduled for completion later this year. Standing tall above the Colne Valley Regional Park and Grand Union Canal in Hillingdon, west London, the bridge faces tricky terrain, needing to cross a series of other water features as well as the A412 road, which runs between Slough and Watford.
The Align JV (Bouygues Travaux Publics, Sir Robert McAlpine and VolkerFitzpatrick), which is building the viaduct as part of the 21.6km Phase One Central 1 portion of HS2, is tackling the difficulties with methods including offsite manufacturing and smart engineering.
Construction work on the viaduct began in early 2021 when the first of 292 foundation piles was constructed. By the time Construction News visited the site in mid-January, the first 480-metre stretch of the viaduct was complete…
Because the viaduct curves to follow the contours of the Colne Valley, each deck segment has a unique shape and is cast in a 105,000 cubic metre temporary factory close to the north end of the construction site…
The work is being delivered through a combination of traditional tunnelling methods and a pair of 170-metre long advanced tunnel boring machines (TBMs) named Cecilia and Florence, which have covered about half the distance so far…
Two precast factories produce the concrete tunnel segments for the TBMs. A total of 112,000 segments are needed to complete both bores in the tunnel, with 58,000 made to date….
The TBMs should reach their destination (the North Portal) by early 2024, but as Jacques warns: “We still have a long journey in front of us.”
