The construction of a new pre-cast factory at the Dunne Group Head Office allowed ConForce Limited to demonstrate the capabilities of post-tensioned ground bearing slabs. The pre-cast factory had internal dimensions of 60m x 30m giving a gross floor area of 1800m². The design criteria for the ground bearing slab was to accomodate mobile crane outrigger loads up to 30 tonne and ConForce Limited were able to design a 275mm flat ground bearing slab using the Westergaard design approach to take these loads with a factor of safety of 1.5.

The slab was characterised by equally spaced flat profile tendons running through the centre of the slab with light reinforcement located around the perimeter of the slabs only. The flat profile tendons provided sufficient pre-compression to the slab to ensure that under the required design loads the concrete section did not exceed its allowable tensile strain. The floor slab was constructed in two equal size pours to allow sufficient time to achieve the necessary finishes on the slabs.