As the largest brownfield development site in Monmouthshire at more than 40 acres, Terra Firma were appointed by the developers of the Old Fairfield Mabey factory and historic shipbuilding site to assess, remediate, and supervise the geotechnical and geo-environmental elements during the transformation of the site to a residential hub. This locally and nationally distinctive location and prominent development demanded a thorough, professional, and collaborative approach to ensure that the local authority, community, and developers could achieve their goals and breathe new life into the industrial site.

With strong links to the local community over the last century, the plans for the site included residential units including sheltered accommodation, retail outlets, office settings, play areas, leisure facilities, community orchards, public squares, and a green corridor next to the river retaining the historic shipyard slipways. This multi-use site with the scars of a heavy industrial past required significant Ground Investigation by the Terra Firma teams over a two year period and innovative engineering to assess and remediate the ground for construction and onward use.

Below ground areas for consideration became apparent when reviewing the site, and the teams applied their many years of experience to assess, plan and execute the GI elements safely ensuring all relevant data could be captured.  As a site of significant archaeological interest, our teams worked sensitively alongside the archaeological services to ensure any intrusive works were carried out appropriately. This was especially important in the vicinity of the slipways and in the pursuit of historic walls. Other geotechnical challenges assessed and engineered by our Terra Firma teams, included ensuring the existing railway line was not compromised by onsite drilling and excavations and undertaking the investigations in complex ground conditions.

Of geotechnical interest was the varied geology across the site and variable conditions encountered. Our Terra Firma teams employed the use of surcharging to compress the soft clays on site prior to loading in construction. As an often-preferred technique to piling, Terra Firma was able to utilise the surcharging on site to fit our client’s brief and prepare for construction.

Having hosted gas, steel and iron works on site post-dating it’s shipbuilding history, the Mabey Bridge site posed some challenges in assessing and remediating any risks to ensure it’s safety for it’s proposed use. Confident in our geo-environmental approach, our teams fully assessed the site, taking any ecological matters into consideration, and identified any hotspots for further works. These included areas of buried asbestos, buried tanks, and industrial contaminants. A full phase 3 report detailed the remediation measures required which were fully supervised by the Terra Firma teams and signed off by the relevant authorities. Ground water monitoring stations demonstrated the effectiveness of the remediation strategies and the works undertaken.

In summary, this large scale complex site of historical significance enabled Terra Firma to fully demonstrate our technical abilities in challenging ground conditions. A full-scale Interpretive Ground Investigation showcasing our Geotechnical and Geo-environmental capabilities supported our client to develop this waterside site safely. Good value approaches served the local community whilst transforming this discarded but significant site for many future generations.