SATEBA UK (formerly Sateba Stanton Precast) were awarded the contract to deliver two innovative, modular design green tunnels for the HS2 project in a move that has created over 100 local jobs and cut embedded carbon in construction by 50%, due to offsite manufacturing techniques.

HS2’s main works contractor, EKFB – a team made up of Eiffage, Kier, Ferrovial and BAM Nuttall, chose SATEBA UK due to their experience and expertise working with precast concrete for over a century.

Both EKFB and SATEBA UK worked with specialist engineers, Matière, who were appointed to install the tunnel segments on site.

Over three miles worth of tunnel were built in thousands of sections at the Ilkeston factory before being shipped to site and assembled at locations in rural Buckinghamshire and Northamptonshire, to reduce disruption and improve efficiency.

Design

Tailored landscaping design plans were developed for each tunnel. Thousands of native trees, including Silver Birch, Oak, Beech and Willow, and shrubs typical to the local area will be planted to create new woodland areas around the portals, and hedgerows and field boundaries on the top of the tunnel.

Designed as a double arch, the tunnel has two separate halves for southbound and northbound trains.

Instead of the whole tunnel being cast on site, five different concrete precast segments are slotted together to achieve the double arch – one central pier, two side walls and two roof arches.

Reduced Carbon

Concrete and steel can be some of the largest sources of carbon emissions within the construction industry and by reducing the amount of both materials needed for the tunnel, this lighter-weight modular approach is expected to more than halve the amount of carbon embedded in the structure.

Offsite production requires less people and equipment on site, improving safety and reducing disruption for residents. Less equipment and lorries also means less truck movements, less fuel and resources.

This method of production also means less waste, and improved quality management with increased accuracy, tolerances and traceability.

Chipping Warden Green Tunnel

The first green tunnel stretches for 1.5 miles (2.5km) past the village of Chipping Warden in Northamptonshire. Once complete, the structures will be covered with earth and landscaped to blend in with the surrounding countryside.

Around 4,970 individual tunnel segments have been produced for the Chipping Warden tunnel.

Watch a video about the Chipping Warden Green Tunnel >

Greatworth Green Tunnel

Segments for the 1.7 mile (2.7km) long Greatworth green tunnel are now being built in the factory in Derbyshire before being shipped to site and assembled over the railway line as it passes the village. Again, it will then be covered with earth and landscaped to fit into the surrounding countryside.

All 5,410 segments installed at Greatworth are steel reinforced (as are the segments for Chipping Warden), with the largest weighing up to 43 tonnes.

Watch a timelapse video of the first segments being slotted together >

Next steps

The tunnels will all have specially designed ‘porous portals’ at either end to reduce the noise of trains entering and exiting the tunnel, these are also being produced by SATEBA UK.

The contract win has brought about an increased SATEBA UK workforce of over 100 people. New production sheds, casting and storage areas have been built at the factory to accommodate the new work. In total SATEBA UK will produce around 10,400 tunnel segments to form the two green tunnels.

The legacy of the new production areas will not stop there and the plan is to continue expanding SATEBA UK’s portfolio, after the HS2 Green Tunnels project has been completed.

Talk to us if you have a major offsite construction project, where you feel precast concrete can help? Email SalesUK@sateba.com.