Balfour Beatty VINCI Begins Major Viaduct Launch for HS2 Over the M6 Near Birmingham
Balfour Beatty VINCI has marked a major milestone in the construction of HS2’s twin viaducts spanning the M6 near Birmingham Airport, as the first section of structural steelwork is now complete.
Designed to minimise disruption for motorists, the 320-metre-long viaducts are being assembled beside the motorway and will be slid into place over three weekends. Each segment will be pushed forward progressively, with new sections added at the rear in a phased approach.
The first structure under construction is the ‘East Deck’, which will carry southbound HS2 trains towards London. The initial 119-metre-long section is scheduled to be moved into position over an adjacent slip road during the weekend of 7–8 June. Subsequent phases will see the viaduct extended over the M6 and the M6-M42 Link Road across two more weekend closures.
As each segment is added, the total weight of the viaduct will increase significantly — starting at 1,300 tonnes and growing to approximately 3,000 tonnes by year’s end. The entire deck is being launched on a slight incline, climbing 4.2 metres from start to finish to maintain control over the push. Upon completion, the structure will weigh the equivalent of 214 double-decker buses.
Russell Luckhurst, who leads the viaduct construction team for Balfour Beatty VINCI, commented:
“We’re entering an exciting phase in delivering these viaducts. By assembling the decks offline and using a phased launch, we’re able to reduce the impact on road users. The ‘East Deck’ will be slid into place across three weekends starting in June, with the ‘West Deck’ to follow in 2026 using the same approach.”
HS2 Ltd’s Senior Project Manager Liam Kenney added:
“It’s fantastic to see the first sections coming together. This is a highly complex engineering task, and I want to thank everyone who’s helped us prepare for the first slide. Our phased strategy builds on lessons from previous projects to help minimise disruption for drivers.”
The viaducts form part of over 200 bridges and viaducts being constructed for the HS2 rail line, aimed at improving travel between London, the West Midlands, and the north of England, while increasing capacity on existing railways for freight and local services.
The operation is being delivered by Balfour Beatty VINCI in partnership with Victor Buyck Steel Construction (VBSC), with support from National Highways. The team is also leveraging experience from the nearby M42/M6 viaduct project.
The deck will be advanced using strand jacks — powerful winches that move the steel at a rate of six to eight metres per hour. It slides along low-friction pads coated with a material similar to that used in non-stick frying pans.
The ‘West Deck’, which will carry northbound trains, is scheduled for assembly and launch in 2026. Due to different pier spacing, four launches will be required to complete this second viaduct.
Both viaducts are being constructed using weathering steel, forming a hollow double-box structure. This steel develops a natural oxide layer that gives it a distinctive rusty appearance while reducing the need for repainting and maintenance.
The structures will be supported by four pairs of concrete piers, the tallest reaching 9.9 metres. To reduce noise and visual impact for nearby residents in Chelmsley Wood, a 4.5-metre-high parapet will be installed on the side facing the community.
