Prefabrication to cut emissions on Thame Valley Viaduct

HS2 Ltd has unveiled the final designs for the Thame Valley Viaduct that will cross the River Thame (near Aylesbury).

Using pioneering prefabricated construction methods that HS2 says will cut its carbon footprint by an estimated 66%, the viaduct’s underside will be just three metres above the ground, with 36 25-metre-long spans crossing the river and surrounding wetlands.

The 35 concrete piers that support the viaduct will be entirely made off-site before being placed on their foundations. The piers will be extended to almost connect with the parapet edge, which HS2 says will “enhance the appearance of a light and narrow structure”.

Thame Valley is one of 15 viaducts designed by HS2’s main works contractor EKFB (comprising Eiffage, Kier, Ferrovial Construction and BAM Nuttall), working with design partner ASC (a joint venture between Arcadis Setec and COWI) and specialist architect Moxon.

“Prefabrication and off-site manufacturing offer huge benefits in terms of efficiency and this design will help us deliver a more efficient, durable and elegant structure with less concrete and steel,” said HS2 Head of Civil Structures Tomas Garcia.

As well as cutting embedded carbon in terms of materials, the prefabrication approach also requires fewer lorries to deliver material to the site, cutting waste and reducing disruption for the community during construction.

Preparatory works have begun on site.