HS2 Ltd and its contractors are claiming a world-first after sliding a 12,600 tonne bridge 165 metres into position across the M42 in Warwickshire.
HS2 Ltd’s civils delivery director, Mike Lyons said: ‘This is the first box slide of its kind over a motorway in the UK, and we believe it’s also the world’s longest slide, so it’s a great achievement for HS2 as we quickly approach peak construction.’
HS2 and BBV worked with National Highways and partners to deliver the 'intricate' operation.
During the Christmas period, a team from Balfour Beatty VINCI (BBV) worked around the clock to move HS2’s Marston Box bridge into place over the motorway.
The operation took 40 hours, at a speed of four metres per hour, from Christmas Eve to Boxing day during a planned 10-day full closure of the motorway between junctions 9 and 10, although it re-opened on Sunday evening (3 January).
The 86-metre structure, which was built on land next to the motorway over the previous six months, has a base, three walls and a top slab.
It was developed by a design joint venture of Mott MacDonald and Systra, working on behalf of BBV. The sliding mechanism was designed by specialist civil and structural engineering company Freyssinet and allowed the box to be pushed into place over the motorway in one movement on a guiding raft over a distance of 165 metres.
This construction method meant only two one-week closures of the motorway over a 12-month period.
Rail minister Huw Merriman described the operation as ‘yet another astonishing achievement by HS2’. He said: ‘Thank you to the 450 people working over the Christmas period on this incredible operation, who are playing their part in bringing this pioneering project to life.’
National Highways senior network planner, Frank Bird said: ‘It’s never easy to close a busy motorway such as the M42 for an extended period of time but it has been vital to ensure the safety of the workforce and motorists while this work is taking place.
‘We’ve been working collaboratively with HS2 for the past 18 months to ensure the operation ran smoothly and to help keep disruption to a minimum for drivers.
'The installation of the new Marston Box bridge is a significant milestone in the HS2 project and it’s great to see it finally in place.’
On completion, the whole structure will be around 190 metres long.
