World’s longest box bridge slide on HS2

A site team of 450 slid a 12,600 tonne bridge a record 165 metres to position it across the M42 during the Christmas period.

The team worked around the clock to move HS2’s Marston Box bridge into place in an operation which took 40 hours, at a speed of 4 metres per hour.

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.

Over the last six months, the 86 metre-long structure was built on land next to the motorway.

The structure, developed by a Design Joint Venture of Mott MacDonald and Systra, working on behalf of BBV, has a base, three walls and top slab.

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.

On completion, the whole structure will be 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.

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.

Sasan Ghavami, Balfour Beatty VINCI’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.”