The K1 Knightsbridge project required the supply and installation of Praeter’s flat jacks to 3 of the basement levels in order to pre-load the retaining structure and allow the ground to be excavated and removed. The flat jacks were installed at the end of the steel props and injected with specialist grout under pressure to pre-load the props and the retaining structure.
Upon completion of the excavation, the concrete floor slabs will be cast under each level of the temporary props, allowing the props to be removed. The loading of the flat jacks using grout allows for the safe removal without having to re-visit to release the hydraulic pressure as the grout locks in this pressure.