Groundforce Shorco’s MP125 and MP250 modular hydraulic props are supporting two large excavations that will house heavy machinery for a new automotive factory in Wolverhampton.
Main contractor Readie Construction is building the £126.3m stamping plant at Four Ashes Park for Gestamp, the international automotive group that produces chassis and components for car-makers including BMW, Jaguar Land Rover, Honda, Nissan-Renault and Toyota.
Groundforce Shorco supplied the equipment to specialist contractor O’Brien Contractors Ltd which has the £4.6m Groundworks subcontract on the project.
O’Brien Contractors Ltd selected Groundforce Shorco to provide structural support for the two excavations that will form the Transfer Press Pit and the Progression Press Pit.
The 6m-deep pits are excavated in poor ground with lateral support provided by secant-piled walls topped with a reinforced concrete capping beam. Groundforce Shorco specified its 125-tonne capacity MP125 hydraulic props to brace the capping beams.
Both pits are large T-shaped excavations with 600mmØ secant piles forming the perimeter walls. The Transfer Press Pit comprises a 70.9m-long main excavation with a 29.4m-long bay extending out perpendicularly at its mid-point. The width of the excavation is 7.6m and 5.9m respectively.
The very similar Progression Press Pit comprises a 63.5m-long main excavation with the perpendicular excavation extending 30.7m. Widths are 9.03m and 5.9m respectively.
The Transfer Press Pit is supported by 18 props placed at 7.15m centres, while 19 props, placed at 6m centres, support the Progression Press Pit.
O’Brien Contractors Limited chose Groundforce Shorco after a lengthy tender process which meant that the supply contract was awarded relatively late in the design process. “Our first site meeting was in December 2016 with the props needed on site in January,” says Groundforce major projects manager Ajay Nagah.
“One of the biggest challenges has been the adverse ground conditions following the wet winter months,” comments project manager Adam Lane. A high water-table and weak soils meant that the excavations have had to be constantly monitored for signs of structural movement.
For this, Groundforce Shorco supplied its advanced load monitoring system to provide continuous measurements of the lateral forces acting on the supports. Three load pins were installed in each excavation with readings transmitted wirelessly to remote devices for constant monitoring.
With only a couple of working weeks between the contract being awarded and the props being delivered to site, it was essential that Groundforce Shorco provided a quick and efficient solution. Instead of installing a separate waling beam around the perimeter of each excavation, all the props were bolted directly to the RC capping beams; offering an economical design. Standard end bearing plates were also used as a form of shear restraint for knee braces; saving fabrication and lead times, whilst offering a uniform drilling template for site to work to.
“Groundforce Shorco has provided 100% technical back-up throughout the project,” comments Obrien’s Project manager Stuart Hopkins. “Everything has gone without a hitch.”
With the concrete base slabs cast and internal supporting walls completed, O’Brien is now preparing to lift the props out of the excavations. The last of the units will be off-hired by the end of July, says Mr Hopkins.