World’s longest box slide delivered by Balfour Beatty VINCI for HS2

Balfour Beatty VINCI has delivered the world’s longest box slide to move HS2’s 12,600 tonne bridge into place over the M42 in Warwickshire, significantly cutting disruption to road users

The 450-person site team worked around the clock to move HS2’s Marston Box bridge into place over the M42 during the 2022 Christmas period. The innovative slide method dramatically cut disruption to road users and is part of HS2’s plan to reduce the impact of construction on local communities.

The operation took 48 hours, at a speed of 4 metres per hour, from Saturday 24 to Monday 26 December during a 10-day closure of the motorway between Junctions J9 and J10 (northbound and southbound). The 12,600 tonne bridge was moved a record 165 metres in total. The motorway reopened on schedule at 0500 on Tuesday, 3 January 2023.

At 163 metres, the box slide used is believed to be the world’s longest.

The structure, developed by a Design Joint Venture of Mott MacDonald and SYSTRA, working on behalf of Balfour Beatty VINCI, has a base, three walls and top slab. All parts of the 86-metre-long structure was constructed on land next to the motorway.

The sliding mechanism, designed by specialist civil and structural engineering company Freyssinet, allowed the box to be pushed into place over the motorway on a guiding raft over a distance of 163 metres – which is believed to be the world’s longest box slide.

This construction method, which allowed it to be moved into place in one movement meant only two one-week closures of the motorway over a 12-month period, dramatically reducing disruption for road users. HS2 and Balfour Beatty VINCI has worked in partnership with National Highways to deliver this intricate operation.

On completion, the whole structure will total around 190 metres in length and will carry HS2 over the motorway as it heads north to Crewe, or on its southward journey as it loops into Birmingham Curzon Street or continues straight on to Interchange Station in Solihull, Old Oak Common Station and London Euston.

Once built, the railway bridge will connect to Dunton Wood Embankment to the south and the Birmingham and Fazeley Canal Viaduct, which crosses the heritage canal, to the north.

Sasan Ghavami, BBV’s construction director for the project said: “We’re extremely proud to have successfully delivered the world’s longest box slide. It’s a huge achievement for our project team and everyone connected with Balfour Beatty VINCI.

“We’ve used innovative construction techniques and worked tirelessly throughout the Christmas period to move this 12,600-tonne bridge over the M42 motorway – all done with the aim of keeping disruption to an absolute minimum.”

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.

“It’s fantastic to celebrate another big milestone for a project that is already providing work for almost 30,000 people today, and in the future, it will encourage people to use zero carbon public transport.”


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