For a jack-up rig structure to be located in the North Sea a practical methodology for footing-soil interaction analysis considering the installation and the operation phases is described. The soil conditions at the location consist of sand underlain by soft clay followed by sand and stiff clay. Penetration analyses are carried out for the skirted footing without/with application of suction. Most Probable (MP) and Highest Expected (HE) skirt resistances are calculated. For the operation phase footing stability and ultimate capacities under storm load conditions are assessed. 2D finite element (FE) modelling is applied as an alternative to the 3D one. The pore pressure increase for dynamic/cyclic (DC) loading is implemented from the critical suction value. For lower/upper bound soil parameters, the footing capacities and stiffness are checked for the given factored load paths. The yield envelopes for V-M (H-constant) and V-H (M = 0) are calculated. The horizontal, vertical and the rotational stiffness are derived applicable to structure analysis.
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