Concrete beams lifted for A417 Missing Link junction
National Highways has reached a key milestone on the A417 Missing Link scheme, lifting 53 prestressed concrete beams into place to form a new underbridge at Shab Valley.
Each beam weighs around 20 tonnes and will support nine lanes of traffic across a 62 m structure, providing access to local residents, businesses and kennels, and linking the A436 and B4070 to the new dual carriageway.
Concrete was selected over steel for the beams due to its lower weight, which enabled installation with a smaller crane, reducing logistics, safety risks and cost. The integral concrete deck also requires less long-term maintenance, with the specification tailored to local environmental conditions.
Celine Acard, National Highways’ senior project manager, said: “We’re really proud of the progress we’re making on this major upgrade of the A417, and work taking shape on the new Shab Valley junction is a testament to our pace and efficiency on the scheme. The new junction will ensure easy access to and from the main carriageway whilst minimising disruption.”
Colin Fowler, head of highways at Tony Gee, who designed the bridge, added: “The philosophy behind the junction design was to work with the natural topography, setting the underpass within the Shab Valley. The integral bridge with precast prestressed concrete beam deck will require only minimal maintenance through its lifetime and importantly will not require closure of the A417 above to do it.”
The underbridge will carry five lanes of the main A417 and four slip roads. A traffic switch to the new alignment is expected in early 2026.
Other recent milestones include installation of steel beams for the 42 m Cowley bridge, a new watercourse created in partnership with the Environment Agency, and extensive biodiversity measures such as planting 130,000 trees, building wildlife crossings and 7.5 km of drystone walling.
The £460m landscape-led project aims to improve safety and reduce congestion on the A417 between Gloucester and Swindon, while leaving a positive environmental legacy.
Concrete Stats – Shab Valley underbridge
- Beams installed: 53 pre-stressed concrete beams
- Weight per beam: 20 tonnes
- Bridge dimensions: 62 m long × 20 m wide
- Traffic carried: 9 lanes (5 A417 mainline + 4 slip roads)
- Construction milestone: Traffic switch scheduled for early 2026
Environmental measures across the scheme include:
- Planting of 130,000 trees and 80 hectares of calcareous grassland
- 7.5 km of drystone walling
- Creation of a new meandering watercourse to replace culvert diversions
- Wildlife protection including bat underpasses, bird fencing and translocation of 2,000 reptiles
The A417 Missing Link scheme is designed to improve safety and connectivity between Gloucester and Swindon, while also reducing congestion and delivering a biodiversity net gain across the Cotswolds.
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