High Speed 2
Work has begun to build what will be the UK’s longest railway bridge.
Ground engineers are now on site sinking the first of nearly 300 piles that will form the foundations for High Speed 2’s Colne Valley viaduct. The viaduct, which will carry 3.4km of HS2 railway across lakes and waterways to the north west of London, will be nearly a kilometre longer than the Forth rail bridge, with trains travelling over it at speeds of up to 200mph.
Set low in the landscape, the bridge will have a series of spans, some up to 80 metres long, crossing the lakes, river Colne and Grand Union Canal. The deck will be about 10 metres above water and supported by 56 piers, with the widest spans used for where the viaduct crosses lakes and narrower spans for the approaches.
Over the next year engineers from HS2 Ltd’s main works contractor Align (Bouygues Travaux Publics, Sir Robert McAlpine, and VolkerFitzpatrick) will construct 292 piles under the ground to support the viaduct piers.
On top of each group of piles, which can extend up to 55 metres into the ground, a concrete pile cap will support the pier, which will in turn hold the full 6,000-tonne weight of the bridge structure above.