In effect, Balfour Beatty Vinci (BBV) is build an A46 underpass offline that will be jacked into place in the coming months
HS2 main works contractor BBV has completed the lid of the concrete box structure ahead of schedule in just 14 days – using three cranes to place 120 concrete beams, ranging between 13 metres and 24 metres long.
The structure is being built on land next to a section of the A46 rather than beneath the carriageway itself to avoiding the need for up to two years of traffic management measures. Instead, a series of shorter, sharper road traffic disruptions will be made.
During the two weekend closures of a section of the A46, from 8pm on 7th February to 6am on 10th February and from 8pm on 14th February to 6am on 17th February, HS2 engineers will upgrade road safety barriers, adjust the layout of the central reservation and undertake drainage works under the carriageway.
Then, some weeks later but at a date yet to be determined, the road will be closed for up to three weeks for the box to be hydraulically jacked into place under the carriageway.
Vinci subsidiary Freyssinet, which specialises in hydraulic jacking and post-tensioning, will push the box across on a guiding raft at a speed of up to 2.5 metres per hour for a total distance of 64 metres.
BBV 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 and precision and I’m really proud of the way they’ve responded to this challenge.
“The next stage includes construction of the deck and installation of the bridge parapets before the bridge can be moved into position under the existing carriageway, allowing HS2 trains to pass underneath.”
