Compensated piled rafts in clayey soils: behaviour, measurements, and predictions

This paper presents a method of analysis of the behaviour of piled rafts in clayey soils, in which a deep excavation was necessary for buildings with two or more basements. In these cases, the piled raft foundations are called a "compensated piled raft." The soil stresses reduce due to excavation, and the reloading of the soil should be taken into account for this kind of foundation. Many important factors that are required to achieve a satisfactory comparison of "measurement versus prediction" are pointed out, and they are grouped in a proposed simplified method of analysing compensated piled rafts using numerical tools that can consider the raft-soil-pile interaction. Finally, two well-known cases of compensated piled rafts (Hyde Park Barracks in London and the Messeturm building in Frankfurt) and a newer building (the Skyper Tower, Frankfurt) are analyzed using the presented approach and the computed and measured time-settlement behaviours are compared.