HS2 has completed works on the first enormous V-shaped piers that will carry the Colne Valley Viaduct over a series of lakes just outside London.
The project is being led by HS2’s main works contractor Align JV – comprising Bouygues Travaux Publics, Sir Robert McAlpine and VolkerFitzpatrick working with suppliers including VSL, Kilnbridge, Tarmac and KVJV.
The Colne Valley Viaduct will carry HS2 trains more than 3km across the Grand Union Canal, River Colne, local roads and a series of lakes between the end of the London tunnels and the start of the Chiltern tunnels.
For the past year, a 700-tonne ‘launch girder’ – the only one of its kind in the UK – has been assembling giant pre-cast concrete segments to form the first 1km of the viaduct deck along the edge of the valley.
Stone skimming
The ‘V-piers’, each weighing 1,800 tonnes, will support a row of arches inspired by the flight of a stone skimming over the surface of the water.
Each pier took nine months to complete.
To allow for the viaduct to curve eastward, each of the one thousand segments that form the arches and deck are slightly different and have been manufactured at a local temporary factory.
Designed to bear the weight of the 80m wide arches over the lakes, the V-piers are twice as large as simpler piers that carry the viaduct over land.
To help the engineers master the complex shape of the pier, a mock-up was built offsite before work began. In total, 11 V-piers will support the viaduct over water with a further 45 piers on land.
