At an early stage of the tendering process Quinn Piling identified that an alternative solution to the precast concrete driven pile option proposed would provide significant advantages for the support of this large-scale housing development. Working closely with the consulting engineer, a value-engineered, soil-tailored vibro replacement stone column ground improvement solution was proposed and developed by Quinn Piling’s engineering team.
The housing development was underlain by varying thicknesses of made ground, deposited many years previously during the construction of a nearby major road scheme. Vibro stone columns up to 4m deep were installed to provide 100kPa bearing support beneath the strip foundations. Further treatment was provided beneath ground-bearing floor slabs.
In 2018 Quinn Piling installed over 4,800 no. vibro stone columns in a 8-week fast-track installation programme, providing ground-improvement support for 197 no. dwellings. This was followed in 2020 by the use of ground improvement under a new retail unit on the site. The shallow, lightly-reinforced strip foundations contributed to reduced spoil creation / materials and were able to be excavated and cast by the main contractor within only 48 hours of the stone column installation, clearly demonstrating the benefit of Quinn Piling’s alternative approach.