HS2 engineers have successfully launched a 130-metre-long steel bridge into position over the Grand Union Canal, reopening it to the public seven days ahead of schedule.
The operation began on Wednesday 4 March, and saw crews slide a 1,620-tonne deck across a country road, canal and towpath near Ufton in Warwickshire.
HS2 engineers installed the Longhole Viaduct over the Grand Union Canal
© HS2 Ltd
Utilising ‘skid shoe methodology’, the move took engineers two days, with two giant hydraulic jacks pushing the structure forward at speeds of up to ten metres per hour. Specialist pads coated in a Teflon-like material were used in order to minimise friction, as well as ease the overall slide process.
The weathering steel viaduct, which was supported by two abutments and two piers on each side of the canal, was then subsequently lowered to its final position and secured in place by 19:00 on Thursday 5 March, bringing to a close two-and-a-half-years of work led by engineers working on behalf of HS2’s construction partner, Balfour Beatty VINCI (BBV).
Peak construction periods saw a team of 40 work on the project, with such times including the installation of 34 piles at depths of up to 30 metres and two concrete piers cast parallel with the canal to enhance the aesthetic for canal users. The project also involved construction of two abutments, and 37 precast planks, which form the base of the bridge deck.
Additionally, a new retaining wall was built to ensure the structural integrity of the canal ahead of the commencement of works. The new concrete-capped wall replaces the an original ‘wash wall’ and soft bank, which is believed to have been formed roughly a century ago.
Any and all vibration levels were carefully monitored throughout the work programme in order to protect the nearby Grade II listed Longhole Bridge, which carries both traffic and pedestrians over the Grand Union Canal between Ufton and Hunningham Hill.
Harry Toase, Balfour Beatty VINCI’s civil engineering lead for the project said:
The team has put in a huge amount of work to prepare for the bridge installation and shown meticulous attention to detail throughout to protect the canal and nearby Grade II listed bridge.
I’m delighted we’ve been able to complete the works one week ahead of schedule and thank the local community for their patience.