MOS Group were contracted to build a new Aldi store and car park. The store and car park were originally designed to be built on CFA piles, with a robust foundation design to transfer loads on the CFA piles.
The site is underlain by up to 1.0m of bouldery cohesive made ground, overlying very soft organic silty clays, containing peaty layers up to 600mm thick. The clays/peat extend to 6.0m below ground level, below which loose gravelly sands are encountered, which become increasingly dense with depth.
Menard proposed using vibrated concrete columns (VCC’s) with enlarged heads (600 mm diameter) in the car park areas. The VCC’s in conjunction with a load distribution mattress enabled the car park areas to be constructed using conventional ground bearing methods. The VCC’s were installed so that they toed into the medium dense to dense sands, where an enlarged bulb was constructed to increase the carrying capacity of the VCC. As the VCC tube was extracted to construct the shaft, the VCC enlarged head was formed on the surface using our “head former”.