HS2 today confirmed that a temporary access bridge - put in place during the construction of the 3.4km Colne Valley Viaduct – has already taken more than 10,000 vehicle journeys off local roads in its first year of operation. As well as taking vehicles off local roads, the 800m long temporary bridge, completed in February 2022, is also used to get equipment out to where the viaducts piers are being built in the lake.
Running alongside what will become the UK’s longest viaduct, the temporary bridge allows construction vehicles to cross a series of lakes and waterways near Denham on the outskirts of London.
Lorries making deliveries to site all arrive from the M25 and follow a 6km internal access route via HS2’s South Portal construction site, and the temporary bridge, instead of using local roads - significantly reducing the impact on the local community during construction.
Construction of the Colne Valley Viaduct is now well underway, with all the foundation pilling for the 56 piers and 2 abutments now complete. The main deck of the viaduct is being built using a ‘launching girder’. The 160m long bridge-building machine is the only one of its kind operating in the UK and is used to lift the giant concrete deck segments that form the viaduct’s arches into position which are being cast in purpose-built temporary factory at the nearby South Portal site. The girder moves from pier to pier constructing the deck as it goes.
Almost 200, out of a thousand deck segments, have now been installed, with each one weighing up to 140 tonnes. To allow for the gentle curve of the viaduct as it crosses the valley, each segment is unique.