HS2 engineers have lifted the last of six enormous viaduct spans that will carry high speed trains over the M42 in the West Midlands, during a weekend closure of the motorway.
The complex multi-stage operation at the Water Orton viaduct site was completed in the early hours of this morning (Monday, 21 September), with the motorway reopening at around 4am as planned.
To take full advantage of the closure, a separate team - three miles to the south – spent the weekend lifting the last beams that will support another major HS2 bridge known as the ‘twin box’.
The 300-metre-long structure near the NEC is formed of two boxes that will support the railway as it passes over the carriageways. This approach has been chosen because of the angle at which the railway must cross the motorway.
The operations at both sites – which builds on progress over four weekends this summer - was led by HS2’s West Midlands construction partner, Balfour Beatty VINCI (BBV).
Engineers can now proceed to the final stages of construction – installing the remaining parapets along the sides of the Water Orton viaducts, and the final concrete pours on the twin box ready for railway tracks to be laid.
HS2 is now at the peak of construction, with site teams focused on boosting productivity route wide. This is happening in parallel with Chief Executive Mark Wild’s comprehensive reset of the project, designed to ensure that the remainder of the work is delivered as efficiently as possible and for the lowest reasonable cost.
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.
“Structural completion of the Water Orton viaducts and the twin box means the end is in sight for our bumper programme of motorway works this year.”
The construction programme was meticulously planned into four weekends, spaced across the summer months, with engineers working on all three structures at the same time to reduce the number of closures.
National Highways seized the opportunity to conduct their own programme of works while the motorway was closed – including demolition of the Bickenhill Bridge at the northern side of the M42 junction 6 roundabout.
Twin box
During the September closure, a 150-strong-team installed the final 44 beams over the southbound carriageway, completing the roof which will carry trains over the M42 near the NEC.
The twin box roof is formed of 175 individual beams, which weigh between 56 and 92 tonnes. 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 now 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, A446, the Birmingham – Peterborough railway line, and the River Tame.
A separate team of 75 men and women have now installed the final two spans of Water Orton Viaduct number 2 over the southbound carriageway – replicating the successful extension of Water Orton 1 in August.
Each 45-metre-long span was built using 18 pre-cast segments, which were 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. They were then locked in place using tensioning cables inside the hollow centre of the viaduct.
The structural design has been carried out by Balfour Beatty VINCI’s Design Joint Venture (DJV), made up of Mott MacDonald and SYSTRA, with WW+P Architects.
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.
“This was a huge engineering challenge and I’m so proud of the way our teams have responded. Their skill, dedication and hard work throughout the summer means we can move forward to the next exciting phase of our work.”
In the coming days, BBV’s engineers will extend Water Orton 2 by a further 40-metres, closing the final gap above Gilson Road.
There will be a further closure of the M42 from 9pm on Friday, 23rd October to 5am on Monday, 26th October to install the viaduct’s parapets on the sections directly above the motorway.
To make full use of the closure, that the same weekend engineers will also carry out the fourth and final slide of the M6 South Viaduct West deck. The M6 carriageway will stay open during these works - only the M42 North to M6 North connector road will be closed.
Progress is also being made on other parts of the project with the platforms now in place at Old Oak Common, the first ‘green tunnel’ complete and the Curzon 2 viaduct on the approach to Curzon Street now in place.
