OWNER:
Berkley Care
ENGINEER:
Ward Associates Consulting Engineers
GENERAL CONTRACTOR:
Lawrence Baker
MAIN FIGURES:
433 Vibro Stone Columns
Project Details
Following successful collaboration on previous projects, Lawrence Baker approached Menard UK to find a cost-effective alternative foundation solution for the construction of a new care home in Wichelstowe, Swindon. The 3-4 storey building will be supported on shallow footings, with loads of up to 210 kN/lm (strip footings) and 1,100 kN (pad footings).
Ground Conditions
The site investigation revealed homogeneous ground conditions on site, with up to 2 meters of uncontrolled made ground underlain by soft becoming stiff clay (Kimmeridge Clay formation). Due to the presence of made ground and soft deposits, a direct construction of the structure without ground improvement would require very deep footings, making it not viable.
Solution
Menard UK offered a solution of Vibro Stone Columns (VSC) allowing the construction of conventional pad and strip footings at shallow depths. This ground improvement solution brought significant benefits to the overall project compared to a traditional piling scheme, by reducing the embodied carbon footprint, accelerating and simplifying the construction sequence, and reducing costs. The VSC have been designed to reduce the residual settlements to 25 mm, with relative differential settlements lower than 1/500, and provided an enhanced allowable bearing pressure to 150 kPa beneath the footings. The final detailed design comprised more than 430 VSC installed to depths of 3.5 to 4.2 m. The VSC works have been completed safely in less than 2 weeks on site and have been verified through a thorough quality control system including one dummy footing test.
Sustainable Development
The use of VSC instead of deep foundations (piles) provided a significant reduction of the embodied carbon of the construction.
