Construction of the Colne Valley Viaduct has now started, overseen by HS2’s main works contractor Align JV – a Bouygues Travaux Publics, Sir Robert McAlpine and VolkerFitzpatrick consortium.
Once complete, the viaduct will be the UK’s longest railway bridge.
A 700 tonne, 160-metre launching girder has now begun lifting the giant concrete deck segments that form the viaduct’s arches into position. A total of one thousand deck segments will be needed, each weighing up to 140 tonnes.
Work on the viaduct’s foundations began in March and a total of 56 piers, each weighing around 370 tonnes, are being sunk along the valley ahead of the girder.
The girder will move from one pier to the next, installing the deck segments as it goes. One segment is put in place each side of the central pier, using a cantilever approach to balance the structure, as two half-arches either side of each pier are constructed simultaneously.
Steel tensioning cables will be threaded through the segments to strengthen the bridge.
To allow for the viaduct’s curves, the segments are all slightly different shapes and made on site at a purpose-built temporary factory. At the peak of construction it will match-cast roughly 12 segments every week.
This approach, where each segment is poured against the previous one, will ensure the whole deck fits perfectly when assembled on the piers.
“I'm absolutely delighted that we have started work to assemble the giant deck segments that will form the Colne Valley Viaduct.
“Once complete, this record-breaking structure will form a key part of the HS2 railway.
“I’d like to thank all those involved in getting us to this exciting stage and look forward to seeing the whole viaduct come together over the coming years.”
Once construction is complete, the factory and surrounding buildings will be removed and the whole area between the viaduct and the Chiltern tunnel will be transformed into an area of chalk grassland and woodland as part of HS2’s green corridor project.
