Giant beams installed ahead of HS2’s ‘innovative’ Warwickshire bridge slide

The concrete beams, ranging between 13 and 24m in length were lifted into place to form part of the structure’s top, using three giant cranes.

HS2 is working on the project with National Highways and HS2 construction partner for the West Midlands, Balfour Beatty Vinci (BBV). A team of engineers completed the operation in 14 days.

The next phase of work will comprise completing the deck and installing parapets.

Due for completion later this year, the box is being built on land adjoining the A46 rather than beneath the road. In spring, the completed structure will be moved into position under the existing carriageway using what HS2 Ltd described as “an innovative technique” utilising automated installation to reduce the impact on road users.

The technique will involve a jacking mechanism, designed by specialist civil and structural engineering company Freyssinet. The system will push the box into place on a guiding raft at a speed of up to 2.5m per hour for a total distance of 64m.

The structural design was carried out by Balfour Beatty Vinci’s Design Joint Venture, made up of Mott MacDonald and Systra (MMSDJV).

MMSDJV engineering manager Tim Akers said: “We’re incredibly proud of the part we’ve played in the development of this structure. Through significant collaboration between HS2, National Highways and Balfour Beatty Vinci, the design has been reviewed and changed from a traditional ‘top down’ approach to an offline construction method with automated rapid and safe installation, reducing the impact to road users significantly.”

HS2, National Highways and Balfour Beatty Vinci (BBV) are preparing for the manoeuvre with measures including road closures.

A section of the A46 between Festival Island in Coventry and Thickthorn Island in Kenilworth will be closed for two weekends next month, from 7 February to 10 February and from 14 February 17 February, for the first stage of preparation work.

During the weekend closures, HS2 engineers will upgrade road safety barriers, adjust the layout of the central reservation and complete advance drainage works under the carriageway. The structure will then be moved into position during a full closure of the A46 Kenilworth Bypass in spring 2025 for up to three weeks.

Commenting on the latest beam installation, HS2 Ltd senior project manager Vicki Lee said: “I’d like to congratulate the entire site team for successfully moving such a large number of beams into place and as we approach the final phase of the A46 box’s construction.

“I also thank motorists in advance for their patience as we prepare for the box push in spring and start our initial stage of preparation work during two February weekend closures of the road. This will allow us to carry out important work directly on the carriageway that would be unsafe for our workforce to do during live traffic.”

Balfour Beatty Vinci project director John McNiffe said: “The safe and successful installation of 120 giant beams is another great achievement for the Balfour Beatty Vinci team who are delivering this box bridge slide in Warwickshire. This 14-day operation required huge amounts of planning.”

National Highways network planner David Patmore said: “Our primary concern is that works on our network cause minimum disruption for road users while still ensuring the safety of both the workforce and those using our roads.

“We work very closely with HS2 and its partners and welcome the innovative techniques being used to meet that objective and reduce the impact that such a major, complex project could have on the travelling public.

“It is good news that the works are progressing so well, and we are grateful for drivers’ patience as the scheme moves towards the box push in the spring.”

In recent weeks, HS2’s construction in the West Midlands has seen the completion of the first stage of work for the construction of a bridge to take the high-speed railway line over the M42 motorway. Two 159m-long steel spans of HS2’s River Cole Viaducts have also been completed near Coleshill in North Warwickshire.

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