Uplift Capacity of Suction Caissons

Prediction of the uplift capacity of suction caissons is a critical issue facing design engineers and rational methods are required in order to produce reliable designs. Extensive theoretical investigations have been carried out of suction caissons subjected to vertical or inclined uplift loading for cases where the behaviour of the seabed soil is undrained, partially drained or drained. A brief literature review on foundations subjected to combined loading is included. Different analytical design models are discussed. Simplified methods for the estimation of the uplift capacity are described, based on the results of the finite element study. The simplified methods are then validated by upper bound theoretical solutions and experiment results. The expressions developed in this paper take into account the influence of the aspect ratio of the caisson, the point of application and angle of inclination of the loading, the undrained shear strength of the soil, the soil permeability and load rate.