UK: HS2 Ltd and contractor Balfour Beatty Vinci completed a milestone in construction of the high speed line on December 24-26 when the Marston Box bridge over the M42 motorway was slid into position northeast of Birmingham.

The 12 600 tonne box bridge was moved into position over a distance of 165 m, which the contractor says is a world record for this type of installation. The bridge was moved at a speed of 4 m/h over a period of 40 h at a location between M42 junctions J9 and J10, requiring a 10-day closure of the motorway which reopened on January 3.

HS2 box bridge slide across the M42 in Warwickshire

The bridge was designed for BBV by a joint venture of Mott MacDonald and Systra. The bridge has a base, three walls and top slab. Over a period of six months, the 86 m long structure was preassembled on land next to the motorway.

The sliding mechanism was designed by civils specialist Freyssinet to allow the box bridge to be pushed into place over the motorway on a guiding raft over a distance of 165 m. Once fully completed, the whole structure will be around 190 m in length, connecting HS2’s Dunton Wood Embankment to the south and the Birmingham & Fazeley Canal Viaduct to the north.

‘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’, said HS2 Ltd Civils Delivery Director Mike Lyons.

‘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’, added Sasan Ghavami, the contractor’s Construction Director for the project.