Construction of a new bridge to facilitate the High Speed 2 (HS2) railway beneath the A43 near Brackley has made significant progress, with the final steel beams successfully positioned during a recent series of weekend closures.

The A43 is a crucial transportation route that connects Oxford, Brackley and Northampton, serving as a vital artery for access to Silverstone and linking the M40 and M1 motorways. The road reopened just after midnight on Saturday, 15 March, following its closure for three weekends to allow for this essential construction work.

Preparatory efforts commenced in 2023, as HS2 engineers collaborated with National Highways to realign the A43, creating an island between the carriageways large enough to accommodate the bridge's construction. Employing a 'top-down' construction method, the team has established 52m deep piled foundations, along with pile caps and piers to support the 66m-long bridge deck.

The construction site recently saw the last of seven steel beams lifted into place using a 750t crane. With these beams now secured, attention will shift towards constructing the concrete deck and parapets. Once completed, the A43 will be transitioned onto the new bridge, enabling excavation to begin for the railway which will run underneath.

This staged construction strategy aims to alleviate traffic disruption, allowing for smoother transit during the ongoing works.

The 80km stretch of railway near Brackley, including the A43 bridge, is being developed by HS2’s principal contractor, EKFB, a consortium that includes Eiffage, Kier, Ferrovial Construction and Bam Nuttall, in collaboration with the design joint venture ASC, which consists of Arcadis, Setec and Cowi.

They worked with National Highways and EKFB’s sub-contractor Kier Transportation to construct the temporary realignment, to keep traffic flowing during the work.

A43 Beam installation view looking along the future HS2 route

HS2 Ltd senior project manager Elizabeth Longinotti said: “The A43 is a busy route between Brackley and Northampton and I’d like to thank drivers for their patience over the last three weekends, allowing us to safely lift the enormous steel beams into position while the road was closed.

“With the beams now in place, we can focus on the next part of this complex multi-stage project – pouring the concrete deck ready for the road to be moved onto the new bridge early next year.”

National Highways route manager Bill Freeman said: “This is an enormous project which will inevitably impact on people using our roads but we have worked very hard for a long time now to keep that disruption to a minimum.

“For a number of years we have been liaising with HS2 and their partners to develop a plan which would reduce the disturbance to road users during the construction of this huge structure.

“We have also taken advantage of the road closures to expedite our own works improving drainage and repairing the slope along the A43, between Brackley and Syresham, reducing the need for further disruption.”

EKFB deputy project director Timothée Scherer said: “The successful execution of the beam lift represents a crucial milestone in our project. This accomplishment underscores the diligent efforts and unwavering commitment of our team, who have meticulously worked to ensure the safe and efficient installation of the beams. This progress brings us significantly closer to the realisation of this essential infrastructure project, which is destined to substantially enhance regional connectivity and transportation.”

Kier Transportation senior project manager Tim Boardman said: “It’s fantastic to see the beam lift take effect, and we’re now starting to see the bridge really take shape. Putting this solution into place has required a huge amount of expertise and collaboration with our partners, and we’re proud of the impact it will have. We look forward to moving onto the next stages of the project, while continuing to work hard to minimise disruption for road users and the local community.”

Nature bridge progresses

In additional developments, significant progress has also been reported at the Turweston Viaduct, closely situated to Brackley, which will be a crossing for wildlife over the high-speed line.

The 80m-long deck beam has been fully positioned after being assembled nearby and then slid into place on specially designed pads. This process utilised PTFE, a friction-reducing material commonly found in non-stick cookware, to ease the installation of the 591-tonne steel structure.

The Turweston Viaduct is part of a series of five viaducts being constructed for the HS2 project that employ an innovative 'double composite' design that incorporates reinforced concrete layers, significantly enhancing structural efficiency and reducing carbon emissions associated with the construction process.

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