World’s longest box bridge slide completed on HS2

The world longest box slide took place over Christmas 2022 to enable the HS2 railway line to cross over the M42 motorway in Warwickshire.

In collaboration with Balfour Beatty Vinci (BBV) teams, Freyssinet worked around the clock over the Christmas period to move the 12,600-tonne bridge structure over 163 metres and into position.

Freyssinet designed and implemented the sliding mechanism, utilising its Autoripage® technique for heavy handling, which enabled the box to be pushed on a guiding raft and into place.

The box bridge slide operation took place between 24 and 26 December. Progressing at four metres per hour, the box was moved into position in under 36 hours, completing well ahead of the programmed schedule. This enabled BBV to proceed with subsequent works and reopen the M42 a day ahead of schedule.

Maria-Teresa Sanchez-Sanchez, Freyssinet’s Project Manager said: “It has been an excellent achievement that has shown the beauty of engineering and the strength of a team working together.”

Autoripage® – a sliding method patented by Freyssinet

Autoripage® is a technique developed by Freyssinet, enabling the installation of a structure entirely prefabricated on a nearby guide raft, to be slid into its final position using bentonite liquid clay as a lubricating layer. After sliding completion, backfilling is carried out to re-open the route to traffic. The method is particularly beneficial for rail and road crossings.

This construction method allowed the 100m long structure to be moved into place in one movement during a one-week closure, reducing disruption for road users on the M42.

Once complete, the structure will carry HS2 over the motorway as it heads north to Crewe, southward into Birmingham Curzon Street or straight on to Interchange Station in Solihull, Old Oak Common Station and London Euston.

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Learn more about the project on HS2 website