HS2 team starts on UK’s first double composite viaduct – video
The first of 38 French-made steel beams that will be used to construct the UK’s first ‘double composite’ structure viaduct have arrived at HS2’s Wendover Dean site in Buckinghamshire.
Manufactured by Eiffage Metal 560 miles away at a specialist facility in France, each of the 25m long steel beams are being transported on the back of extra-long lorries to the Buckinghamshire site.
Engineers have come up with the innovative design to create a lower carbon structure than traditional designs.
Instead of using solid pre-stressed concrete beams to form the bridge spans, the viaduct will use two steel beams sandwiched between two layers of reinforced concrete to create a lightweight and super strong hollow span.
The double composite approach is stronger allowing project engineers to save an estimated 7,433 tonnes of embodied carbon through the use of less material.
This is the equivalent of someone taking 20,500 return flights from London to Edinburgh.
Once the rest of the 40 tonnes beams have completed their long journey to site, the beams will be welded together to form the 450m-long viaduct.
As well as manufacturing the steel, Eiffage Metal will also be leading on the installation of the beams
Over the summer, HS2 main works contractor, EKFB – a team made up of Eiffage, Kier, Ferrovial Construction and BAM Nuttall – will weld the beams together for the first of five 90m long spans.
Pre-cast concrete sections will then be added to form slender box-like structures. These will then be slowly pushed out from the north abutment onto each of the concrete piers later this year.
EKFB worked with their design partner, ASC – a joint venture between Arcadis, Setec and COWI – and specialist architects Moxon on the ‘double composite’ approach which was inspired by structures on the French high speed TGV network.
Senior EKFB engineer James Collings said: ‘There’s been a tremendous amount of effort put in to get to this stage of construction, including an extensive earthworks and utilities programme and beam delivery is a key milestone for the team.
“As momentum gathers pace and we continue our preparations for the bridge deck launch, it’s great to see these steels on site, ready for the next phase of build. We’re starting to see the viaduct emerge from its foundations and start to take shape above ground.”