HS2: Wendover Dean Viaduct deck slide completed

Images released by HS2 showcase the eight-month engineering operation that saw the assembly of Wendover Dean Viaduct's 450m deck.

The deck, which weighs the equivalent of 264 double-decker buses, was assembled in three stages.

Each section was attached behind the previous one and pushed out from the north abutment, resulting in a weight increase with every push.

The Wendover Dean Viaduct deck slide has been completed after eight months (Image: HS2)

It started with an initial 590 tonnes and gradually increased with each attachment until it weighed 3,700 tonnes.

During the slide, special pads covered in Teflon - a material usually found on the surface of a non-stick frying pan - were used to minimise friction between the deck and the temporary steel bearings on top of each of the concrete piers.

HS2's, head of delivery, Nicola Henderson-Reid, said: "The last eight months have been incredible, and I’d like to thank everyone involved in getting us to where we are today.

"It’s been fascinating to watch the deck slowly inch into position, and we now look forward to the next stage of the project - lowering the deck into final position and completing the complex concrete work that will support the new railway."

The next stage will see the deck being lowered 60cm onto the permanent bearings which will eventually support the viaduct's full weight.

The Wendover Dean Viaduct deck slide has been completed after eight months (Image: HS2)

The two-month long operation will see the steelwork above each pier lowered by 20cm at a time, pier-by pier, until the whole 450m long deck settles into its final position.

Work can then begin on the concrete that will support the railway using a specially designed travelling formwork. 

This operation is expected to last approximately a year, after which parapets will be installed alongside the viaduct’s edge.

The Wendover Dean Viaduct is the first major railway bridge in the UK to be built with a ‘double composite’ structure, which uses significantly less carbon-intensive concrete and steel than a more traditional design.

The Wendover Dean Viaduct deck push in May (Image: HS2)

This design encompasses two steel beams sandwiched between two layers of reinforced concrete to create a super-strong structure.

Civil engineering firm EKFB’s senior project engineer, James Collings, said: "The final launch for Wendover Dean viaduct marks two years of teamwork from EKFB and our supply chain partners Eiffage Metal.

"I am very proud of our progress and would like to thank the team for their ongoing commitment to the safe delivery of the viaduct.

"Over the next three months, we will see the viaduct lowered onto its permanent bearings in preparation for its concrete deck."