Video: HS2 begins year-long, half-kilometre viaduct deck slide
Engineers this week began a delicate job that will see almost half a kilometre of bridge deck slid into position over the next year, high above the Misbourne Valley in Buckinghamshire, as HS2’s innovative Wendover Dean Viaduct enters a critical new stage of construction.
Material similar to that found on non-stick frying pans was used to slide the first of three giant sections into place over 9 hours on Wednesday 10th January.
Engineers used a winch to carefully push the deck forward at a speed of around 9m per hour, sliding across Teflon pads to reduce friction – a material usually found on the surface of a non-stick frying pan. It is the longest deck slide on the HS2 project to date.
The 450m-long viaduct will be the first major railway bridge in the UK to be built with a ‘double composite’ approach, which uses significantly less carbon-intensive concrete and steel than a more traditional design - and has allowed HS2 to halve the amount of embedded carbon in the structure.
Due to the length of the viaduct, the deck is being assembled in three stages, ranging from 90m to 180m sections, with each one pushed out from the north abutment before the next section is attached behind it.
This painstaking process means that the weight of the deck will increase with each push, up from an initial 590 tonnes this week to 3700 tonnes by the end of the year.
EKFB worked with their design partner, ASC (a joint venture between Arcadis, Setec and COWI) and architects Moxon on the ‘double composite’ approach which was inspired by structures on the French high speed TGV network.
The approach is set to cut the carbon footprint of the structure by 56% – saving almost 13,000 tonnes of embodied carbon – and helping HS2 achieve its goal of halving the amount of embedded carbon in construction.
Wendover Dean Viaduct is one of 50 major viaducts on the HS2 project – which is designed to improve connections between London, Birmingham and the North while freeing up space on the most congested southern end of the existing West Coast Main Line.
In total, HS2 is building more than 500 bridging structures – ranging from small road bridges to massive viaducts like record-breaking Colne Valley Viaduct which will become the longest in the UK.
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