Roger Bullivant provided foundations for a new Agricultural Young Stock building for Harper Adams University.
Roger Bullivant set out a programme utilising vibro stone columns to improve the ground, the site in Shropshire, being unoccupied agricultural land previously. This was the most cost effective technique to support the designed structure in the prevailing ground conditions.
The ground conditions were determined by exploratory trial pits. Which revealed the site to be underlain by the Bridgnorth Sandstone Strata.
The sandstone is soft and at depth of 3-3.15m. In some locations superficial deposits of bolder clay masked the sandstone. Below this at around 2.2m and 3.6m the ground material comprised of medium dense gravely sand, including pebbles of quartz with some sandstone.
A total of 632 stone columns were installed over the floor slab surface area. The scheme was designed to provide a total baring capacity of 125kN/m2 below the foundations and below the floor slab to 20kN/m2.
The vibro stone column process densifies the ground which increases bearing capacity and reduces settlement potential of variable superficial deposits.
Settlement was predicted to be excessive on this site, however the densification of the ground utilising vibro stone columns controls the amount.
The stone columns were placed to support the footings, floor slab and the concrete apron.
Once the vibro stone columns were installed the ground around the foundations was reduced which allowed for the construction of the footings.