The Project
The South Clyde Energy Centre in Glasgow is set to become one of Scotland’s most significant energy-from-waste facilities. Owned by Fortum and Gren Energy, the plant will divert up to 350,000 tonnes of non-hazardous waste from landfill each year and generate enough electricity to power around 70,000 homes.
As part of the construction programme, a 34-metre by 25-metre waste bunker had to be excavated and supported. Contractor Careys sought Groundforce Shorco to deliver a bespoke temporary works solution that could manage the site’s demanding conditions and enable safe progress on this critical stage of the build.
The Challenge
The bunker excavation proved particularly complex due to a combination of poor ground conditions and unusually high structural loads. The rectangular geometry of the bunker made the design even more demanding, as forces became concentrated in the centre.
Some of the excavation corners experienced such extreme pressures that conventional hydraulic props could not cope, requiring alternative solutions. On top of the technical challenges, logistics also had to be carefully managed, with propping equipment remaining in place for six months and deliveries scheduled from Groundforce Shorco’s Derby depot, sometimes arriving two or three times per day.
The Solution
Groundforce Shorco designed a two-tier propping system that balanced strength, efficiency and practicality.
- The Super Mega Brace, the heaviest proprietary beam currently available, was deployed and twinned in the centre to absorb concentrated loads from knee-braces.
- MP375 hydraulic props were installed throughout the excavation and monitored in real time to ensure safe performance.
- 813mm-diameter tubular props were used in place of larger 1220mm tubes, providing strong capacity while allowing more efficient muck-away and better site clearances.
In the most heavily loaded corners, Groundforce Shorco developed custom-fabricated steel props with thicker tube walls to handle pressures beyond hydraulic limits. The design approach evolved over time, thanks to early engagement with Careys. More than a year before excavation began, both design teams started collaborating, which allowed the original piled wall concept to be adapted to a more resilient combi wall.
Daily monitoring confirmed that loads remained within tolerance, while logistics were meticulously managed to avoid disruption to the programme.
The Results
The temporary works were in operation for six months and performed as designed, enabling the safe and successful completion of the bunker excavation.
Continuous load monitoring confirmed the system’s effectiveness. As Careys’ Senior Project Manager Pat Grenham noted, “The props haven’t been over-strained, so obviously the design is working. Along with load monitoring, we also survey whether there’s any deflection or movement in the props.”
The project also delivered valuable lessons for future schemes, particularly the twinned waling beam design. Robert Powell, Principal Engineer at Groundforce Shorco, explained:
“What we’ve done before is twin the whole frame, so you end up with a double level frame to share the load. But having spoken to some of my colleagues who have done similar things in Europe, they suggested just doing this locally, which almost halved the amount of waling beam needed and reduced the number of struts. That’s certainly something we can take forward.”
Beyond engineering innovation, the project also reinforced both companies’ sustainability commitments, with Groundforce Shorco highlighting the reuse potential of its hydraulic kit and Careys emphasising the use of FSC-certified timber, recycled materials and low-emission plant.
Reflecting on the success of the scheme, Pat Grenham added: “I’ve worked with Groundforce Shorco on numerous projects. The pictures will paint a thousand words. Once you look at them you can see the achievement. We’ll give the end user a product that everyone should be proud of.”
Quotes provided by Project Scotland