HS2 has completed the final structural lifts at the Water Orton viaducts and the nearby twin box near Birmingham, ending a summer programme of four M42 weekend closures led by Balfour Beatty VINCI.
HS2 engineers have lifted the last of six viaduct spans that will carry high-speed trains over the M42 in the West Midlands, during a weekend closure of the motorway.
The multi-stage operation at the Water Orton viaduct site was completed in the early hours of Monday 21 September, with the motorway reopening at around 4am as planned. A separate team, three miles to the south, spent the weekend lifting the last beams for another major HS2 bridge known as the twin box, near the NEC.
Twin box roof completed
Both operations were led by HS2’s West Midlands construction partner, Balfour Beatty VINCI (BBV), and build on progress made over four weekends this summer. Engineers worked on all three structures at the same time to reduce the number of closures.
The twin box is a 300-metre-long structure formed of two boxes that will support the railway as it passes over the M42 carriageways. This approach was chosen because of the angle at which the railway must cross the motorway.
During the September closure, a 150-strong team installed the final 44 beams over the southbound carriageway, completing the roof. In total the roof is made up of 175 individual beams weighing between 56 and 92 tonnes each. A 300-tonne crawler crane lifted and lowered each of the 23-metre-long beams into position, bridging the gap between the supporting walls and columns either side of the carriageway and inside the central reservation.
The completed structure stands 10 metres high, with two 145-metre-long walls and 46 internal columns supporting the 9,800-tonne beamed roof.
Water Orton viaducts
The two Water Orton viaducts form the top of the triangular delta junction, linking Birmingham with the mainline heading north. They cross the M42, the A446, the Birmingham to Peterborough railway line and the River Tame.
A team of 75 installed the final two spans of Water Orton Viaduct 2 over the southbound carriageway, repeating the extension of Water Orton 1 carried out in August. Each 45-metre-long span was built from 18 pre-cast segments manufactured locally at BBV’s concrete batching plant in Kingsbury.
Once assembled, the 1,000-tonne spans were driven into position using self-propelled modular transporters, then locked in place with tensioning cables inside the hollow centre of the viaduct. Structural design was carried out by BBV’s Design Joint Venture, made up of Mott MacDonald and SYSTRA, with WW+P Architects.
Agnes Usciak, HS2 Ltd’s Senior Project Manager, said: “I’d like to thank motorists and local residents for their patience during this huge programme of work – our biggest yet over the motorway network. Splitting a huge construction programme into four separate weekends requires meticulous planning, and our engineers executed the entire operation with pin-point precision, ensuring the motorway reopened on time, every time.”
Oliver Shore, Project Director for Balfour Beatty VINCI, said: “The twin box and Water Orton Viaducts are three major structures that cross the busy M42 motorway. In just four weekends, we’ve completed the bridging works on each of them, closing the gap over the north and southbound carriageways.”
Work continues ahead of October closure
Engineers can now move to the final stages of construction, installing the remaining parapets along the sides of the Water Orton viaducts and carrying out the final concrete pours on the twin box, ready for track to be laid. In the coming days, BBV will extend Water Orton 2 by a further 40 metres, closing the final gap above Gilson Road.
A further M42 closure is planned from 9pm on Friday 23 October to 5am on Monday 26 October to install the viaduct parapets on the sections directly above the motorway. During the same weekend, engineers will carry out the fourth and final slide of the M6 South Viaduct West deck. The M6 carriageway will stay open, with only the M42 North to M6 North connector road closed.
HS2 said it is at the peak of construction, with site teams focused on boosting productivity across the route, alongside Chief Executive Mark Wild’s reset of the project to deliver the remaining work as efficiently as possible and for the lowest reasonable cost.
Elsewhere on the project, platforms are now in place at Old Oak Common, the first green tunnel is complete and the Curzon 2 viaduct is in place on the approach to Curzon Street.
No comments yet