Last of 56 piers built on HS2’s longest viaduct

Construction of all the supporting piers of HS2’s viaduct across the Colne Valley has been completed after more than two years’ work over land and water. The deck segment cast on-site for the most southerly v-shaped pier over the Harefield Lake, completes the final pier for the viaduct. The v-piers form the arch of the deck over the lakes with a range of vertical, fixed buttress and expansion buttress piers over the land. The piers will support the viaduct’s deck for 2.1miles across the Colne Valley. 43 tonnes of concrete were poured into the formwork containing high-strength reinforcement steel and carefully set out post tensioning ducts, to complete the final deck segment on the v-pier. With the formwork now removed the complete final pier is revealed. Using a giant launching girder to install the viaduct’s remaining 1000 deck segments pre-cast in a factory on-site, requires piers to be built in advance, ready for the girder to move onto as it makes its way from north to south across the Colne Valley. Highly efficient and precise project management is being maintained throughout the build to ensure the programme’s forward momentum. The viaduct construction is being led by HS2’s main works contractor Align JV – that includes Bouygues Travaux Publics, Sir Robert McAlpine and Volker Fitzpatrick.