The foundations and basement contract included major design development responsibility. The overriding requirement in constructing the foundations was to limit movement of the diaphragm wall during basement excavation and non-linear elastoplastic analysis incorporating soil-structure interaction were carried out to calculate total movements.

Construction of the foundations required the sinking of eight 25m deep 9.9m diameter caissons. Adjacent to the wall these created stability and movement problems which required three-dimensional analysis of the entire site at all stages.  The analysis also ensured that the stringent deformation restrictions on the caissons themselves were met.  TGP also designed 58 x 2.0m internal diameter seawater intake caisson.  In addition, we were responsible for the design of hydraulically operated self-lowering floor soffit floors up to 1m thick; the high-speed soil hoist and transfer gantries and all temporary propping within the excavations.