South Clyde Energy Centre is an Energy-from-waste-facility (EfW) currently being constructed on the outskirts of Glasgow, in the sheildhall area of the city. The facility, which is due for completion in 2026, it will generate enough lower carbon electricity to power the equivalent of around 70,000 homes by processing up to 350,000 tonnes of residual non-recyclable waste each year which would otherwise be destined for landfill or export. Compared to landfilling, South Clyde Energy Centre is also expected to reduce greenhouse gas emissions by 67 kt CO2e per year.
A key part of the construction of the facility was forming the waste bunker in the centre of the site. This required a steel combi-wall cofferdam consisting of 42nr 1468mm diameter tubes 31m long, 42nr pairs of ZZ28-700 infill sheet piles 22m long, and 8nr Larssen L24 sheet piles 22m long, totalling approximately 1,245 tonnes of steel. SPI were engaged by Cementation Skanska Ltd to supply and install the combi-wall cofferdam and were able to provide specialist advise during the pre-construction stages to ensure a workable design was arrived at.
This large-scale installation was required to facilitate an excavation of approximately 12m to form the reinforced concrete base slab and liner walls of the waste bunker. The combi-wall was required to be water-tight and this was satisfactorily achieved through the site application of Biguma bituminous sealant to the clutches of the combi-wall tubes and factory applied sealant to the central interlock of the infill sheet piles.
Installation of the combi-wall cofferdam was carried out using conventional piling methods with a Liebherr LR1160.1 crawler crane, PVE 24VM and 52VM vibratory hammers, and BSP CX85 and CG210 impact hammers. The tubes and sheet piles were supplied by Stabau, with the tubes manufactured in China and shipped via Rotterdam up the River Clyde into King George V Dock, less than 1 mile from site. The sheet piles were transported from Europe via road.
The Temporary Works Designs for the bespoke piling gates required for the installation of the combi-wall cofferdam were provided by SPI’s design team. This included a main piling gate setup for the combi-wall tubes with 24m long UC spud piles supporting two levels of piling gates, as well as guide frames for the installation of the infill sheet piles, and a support frame for the spud piles to be pitched into before being driven with the vibratory hammer.