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25 years

of operational energy use saved in embodied carbon

1,291 Tonnes

carbon saved via low-carbon concrete

28% less

embodied carbon in design and materials

Cutting embodied carbon at Stockport Interchange

Innovative design and low-carbon concrete save embodied carbon at new transport hub equivalent to more than 25 years of operational energy use.

We aim to deliver net zero embodied carbon in all our customer's projects by 2040.

At Stockport Interchange - a new transportation hub bringing greater connectivity to Greater Manchester - Willmott Dixon collaborated with our project partners to significantly reduce embodied carbon through changes to the design and materials used.

The interchange is part of a £1 billion town centre redevelopment initiative linking the town centre and railway station with a network of cycleways and riverside paths. It features a two-acre rooftop park, bringing improved leisure and recreation opportunities and enhancing local biodiversity.

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Efficient Design

By placing sustainability at the heart of the design process, we helped reduce the total amount of concrete used across the project by 2,775 tonnes. We worked with structural engineers, Renaissance, to make considered design amendments which would not dilute the agreed design intent; for example, reconfiguring the beam arrangement to the soffit of Oculus, reducing the number of beams required in each bay, making the project easier to build. This alone saved 853 tonnes of concrete, as well as extensive amounts of formwork, and enabled further reductions in the foundations of 1889 tonnes. This reconfiguration resulted in total savings equating to an 11% reduction in concrete use, in turn reducing the project’s embodied carbon by 460 tonnes (10% reduction).

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Low Carbon Concrete

Further embodied carbon savings were achieved through the use of ground granulated blast furnace slag (GGBS), a low embodied carbon alternative to cement, in the concrete beams, slabs and columns. The use of 60% GGBS concrete, while delivering embodied carbon savings, was actually driven by the technical requirements to control the rate of curing. As a consequence, this delivered further savings of 831 tonnes of embodied carbon.

Through careful design choices, and the use of low-carbon concrete, we helped remove a total of 1,291 tonnes of embodied carbon from the overall project (28% reduction). Overall, the carbon saving project scheme at Stockport Interchange successfully eliminated embodied carbon from the building equivalent to more than 25 years of operational energy consumption.

The project also benefitted from Willmott Dixon’s partnership with an experienced and trusted supply chain partner, Mayo Civil Engineering. Their input further contributed to the success of the project with efficient delivery and high-quality finish. We also worked with the supply chain to source connecting dowels that could accommodate the seasonal movement of the structure, eliminating costly details from the original design.

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Chart shows reductions in embodied carbon achieved through design and materials.

Helen Gribbon, Structural Engineer with Renaissance, said: “The project brief was to develop solutions that were as low in embodied carbon as possible, whilst equally being efficient, pragmatic and buildable.

“The result is an engineered form which has provided the opportunity for the collective success of all parties involved, ensuring its deliverability on site, meeting a stringent programme, working with and not against the site constraints.”

Michael Blackburn, Principal Surveyor with Willmott Dixon, said: “The Stockport Interchange project has enhanced our capabilities to deliver sustainable concrete framed design in the Northwest region.

“The decision to strike a single-source agreement with a well-respected concrete frame contractor, Mayo Civil Engineering, provided certainty about the design from an early stage and ensured we faced no challenges around material supply, costs or concrete mix design. In recognition, Mayo was awarded the productivity award at our recent supply chain awards.”

The Interchange project for Transport for Greater Manchester, Stockport Council, and the Greater Manchester Combined Authority is on track for completion in Spring 2024.

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The project (pictured above in November 2023) is set for completion in Spring 2024.