OWNER:
Fix Auto
ENGINEER:
Paul Waite Associates
GENERAL CONTRACTOR:
MSM Construction
MAIN FIGURES:
c.2,700 CMCs
Project Details
Menard has provided a ground improvement solution for a small but complex site for a new commercial garage facility. This was an alternative to piling which was proposed initially.
Ground Conditions
The new building is located over a former gas tank holder with significantly different ground conditions in and outside of the former tank. Additionally, the tank foundations were still in place and the solution had to work around this.
Solution
We were able to provide the contractor with a value engineered solution using ground improvement techniques. This enabled a reduction in foundation costs of around 50% compared with the original piled solution.
Additional site investigation by CPT was recommended by Menard. This enabled a better understanding of the variation in ground conditions and informed the development of a detailed design to ensure that the performance of the Controlled Modulus Column (CMC) solution met the total and differential settlement criteria.
The CMCs within the footprint of the former gas tank extended through the soft clay fill and terminated at around 9.5m founding in dense sands. Outside the former gas tank the CMCs were shorter at around 5-6m founding in medium dense sands. The CMC layout was adapted to avoid the known obstructions of the tank foundations.
The site was also located in close proximity to a live rail running on an adjacent viaduct. With this restriction, the CMC method presented benefit over CFA piles as there was no risk of spoil being carried up the auger as a displacement drilling tool is used.
