Application of deformation adjustors in piled raft foundations

This paper introduces a new device called a deformation adjustor to improve the performance of piled raft foundations in supporting high-rise buildings. The deformation adjustors are placed between pile head and raft to optimise the stiffness distribution in the piled raft system so that the differential settlement can be minimised and the potential bearing capacity of subsoils can be effectively utilised. They are particularly promising for piled raft foundations in complicated loading, construction and subsurface conditions. This paper first describes the development of the deformation adjustors and the installation procedures in piled rafts, followed by their potential applications to piled raft foundations in different challenging conditions. The possible challenging applications include piled rafts with end-bearing piles, reuse of old piles as a part of the piled rafts and piled rafts in complicated geological conditions. The preliminary design procedures for each application are also discussed. At the end of this paper, a case history is documented to show the potential of using deformation adjustors to improve the performance of piled rafts.