Water Orton Primary School, Birmingham
Thomas met the imposing challenge of poor ground conditions for this school scheme through hard work and ingenuity. His cement-stabilisation of the ground avoided the cost and community disruption of trucking 9,000 cubic metres of soil off site. His use of steel-tube piling captured further cost and time savings. And his ability to progress beam-and-block flooring as the critical-path roofing activity went on above delivered programme, budget and a defect-free build to a very satisfied client.
About the Project
Client: Warwickshire County Council
Contract: NEC 3 option A
The predesigned Sunesis-type single-storey school that Thomas Prince built here offers big advantages in the form of defined layout, upfront specification, fixed cost and known time to construct. Sadly, it cannot take account of ground conditions, which were the great challenge on this scheme. It was one that Thomas ultimately overcame with impressive hard work and ingenuity.
Right from the start, the unpromising presence of 600mm of topsoil on the site found in the ground testing was a problem for a scheme that required substantial foundations. To avoid the cost (and community impact) of trucking soil off site, Thomas brought in a ground remediation specialist who was able to keep 9,000 cubic metres (570 lorryloads) of excavated material on site by cement-stabilisation and cut and fill works.
With the bearing substrate deep below the finished floor level, the original plan was to put in continuous flight auger piles, with all the attendant expense of steel reinforcement and a vast amount of concrete. However, having used steel tube piles on past projects, Thomas decided to put the steel in direct and eliminated concrete by driving in recycled gas-line pipework. He made making substantial cost and time savings by doing so.
Potential heave from the established ground conditions prevented the installation of a standard Sunesis floor of in-situ concrete, so Thomas went for a beam and block construction with screed topping. Straightforward enough, surely? Indeed, but beam and block took five weeks rather than two for concrete pours – a significant time loss on a short programme. He resequenced to build the flooring with the help of a gun-carriage forklift once the metal deck roofing had been installed, with the rest of the critical path roofing activity going on above as the beam and block was installed below.
The result: one Sunesis-model school delivered on programme and on budget, not to mention defect-free, to a very satisfied client.