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Glasgow Airport Investment Area (GAIA), 2020


Keith Fernandes & Stuart Angus

Carbon Conscious Construction

As a Carbon Neutral Contractor, Wills Bros were delighted to be one of the first in the world to adopt and embed the PAS2080 (Carbon Management in Infrastructure) standard methodology on the GAIA project and through each of our teams involved. Implementing the standard saw us consistently and transparently quantify and assess our carbon spend throughout the infrastructure delivery process – promoting collaboration and efficiencies along the value chain; and importantly, delivering carbon and cost reduction.

An example of saving on this project was the significant 1500 tonne saving of carbon through a carbon-conscious design change from a reinforced-concrete cable protection structure to a lightweight embankment utilising recycled plastic geo-cellular crates. Furthermore, this project’s success has enabled Wills to be featured in the New Civil Engineer, be shortlisted as a Sustainable Infrastructure Project of the Year with Edie and be a contender for Carbon Champion status with the Institution of Civil Engineers. (Author Chris Landsburgh)

Details on the 132 kV structure

Our works on the Glasgow Airport Investment Area project involved providing suitable protection measures to a series of fragile high voltage (132kV) cables which one of our new roads has to cross.

The client had prepared preliminary proposals for the protection measures which involved a series of steel reinforced concrete beams spanning an array of reinforced concrete piles. The solution was carbon intensive and the asset owner (Scottish Power Energy Networks) had raised concerns about the potential for damage to the cables during any vibratory works such as piling. This was particularly relevant because the cables were the old oil-filled type (installed approx. in 1940s) and they have a strategic importance in providing electricity supply to a large area around Renfrew.

An assessment into the carbon footprint of the project proposals undertaken prior to our involvement determined that the reinforced concrete proposals developed by the client had an impact of 1,546.3 t.CO2.e which was almost 13% of the whole project’s projected footprint.

We explored alternatives with our designer whilst prioritising solutions which minimised disturbance to the sensitive assets and utilised sustainable materials. The final solution involves the innovative use of Wavin Aquacell units (recycled plastic hollow crates – typically used for storage in drainage applications), geogrid reinforcement and lightweight concrete and fill which minimises the self-weight loading of the protection measures and avoids disturbance during installation. The carbon footprint of this solution is a fraction of the original proposals due to concrete and steel being largely eliminated from the design in favour of hollow recycled plastic crates (95% voids).

How Wills Bros cut carbon by 87% on a high-voltage cable crossing

The traditional carbon culprits of concrete and steel were switched for recycled plastic and air in this innovative lightweight embankment solution for a high-voltage cable crossing

Read the full article at ICE website here.