Large diameter CFA piles installed on university site by Roger Bullivant Ltd Monday, 10th November 2008
The company is creating 180 piles of 750mm diameter to form a contiguous piled retaining wall, to allow the level of the ground to be lowered from one side of the new development. The company is also installing 250 piles of 600mm diameter to pick up point loads beneath the two new buildings. Work is being carried out on behalf of the University of Worcester ahead of a handover date to the client of 31 August 2009.
Use of such large diameter bored piles was preferred to installing conventional driven precast foundations because of the variable nature of ground on site. RBL contracts manager Will Payne said: “The site is formed of made ground overlying a strata of dense sand, clay and weak mudstone that would not have easily supported the required loads had precast piles been specified. Our large diameter CFA piles are proving very effective in these ground conditions.”
Augered foundations for the piled retaining wall are being installed to depths of up to 15m using a 750mm diameter continuous flight auger powered by a high masted, high torque 7006 series rig. Between 70 and 80 ground anchors are set to be installed between individual piles in the retaining wall at an angle of 55 degrees to provide added structural support when ground is excavated from one side.
The 600mm diameter piles designed to support the new student accommodation blocks extend to between 10m and 11m and will accommodate point loads of up to 800kN. The new development will feature three and four storey buildings formed using precast concrete.
The site of the new student blocks stands beside Worcester’s former red brick Royal Infirmary buildings, which are set to be refurbished for use as a teaching facility by the university. Development at the site is being carried out in three phases, with the first phase construction managed by Costain in an £85M deal.
