HS2 engineers have put the finishing touches to a 320m-long viaduct that will carry high-speed trains across a floodplain of the River Great Ouse near Brackley.

The viaduct, built using a ‘double composite’ approach, is located east of Brackley near the village of Westbury.

Engineers working on the project took inspiration from recent viaducts on the French TGV network, which use less carbon-intensive concrete and steel than more traditional designs.

Rather than using a concrete span or a steel beam supporting a concrete deck, the double composite method places reinforced concrete above and below the steel beam to create a more efficient box-beam structure.

The completed Westbury viaduct on the HS2 route near Brackley.

placeholder image — The completed Westbury viaduct on the HS2 route near Brackley.

The 2,695-tonne steel beams were assembled on the north abutment before being slid into place between March and October 2024. Special non-stick pads were used to reduce friction as the beams moved across the concrete piers.

The concrete deck was then cast in 42-metre sections using travelling formwork, before prefabricated parapets were lifted into position along the edges.

Paul Cooper, senior project manager at HS2 Ltd, said: “It’s been amazing to watch Westbury viaduct come together over the last few years and I’d like to thank everyone involved in getting this incredible structure over the finishing line.

“This section of the railway is now really starting to come together, and with the viaduct complete, our focus will turn to completing the earthworks and other nearby structures.”

The viaduct is one of 15 being built by EKFB, HS2 Ltd’s main works contractor for the central section of the project.