Centrifuge observations on multidirectional loading of a suction caisson in dense sand

This paper presents centrifuge tests undertaken to investigate the combined VH capacities of suction caisson in sand under multidirectional loadings following series of low magnitude horizontal cyclic loading. These loading paths are relevant to foundations of array of floating renewables such as wave energy converters or wind turbines. The centrifuge tests mainly provide information about the V-H yield envelopes in different loading directions and the H-x-H-y yield envelopes in the horizontal plane so that the effect of multidirectional loading can be analysed. The evolution of the yield envelope after cyclic loadings is first presented. Yield envelopes for load change angle beta of 60 degrees, 90 degrees, 120 degrees from the initial horizontal cyclic loading direction are then presented, and the mechanisms for increased capacity for beta > 90 degrees and reduced capacity for beta <90 degrees are discussed.