A COMPUTATIONAL MODEL FOR FIXITY OF SPUD CANS ON STIFF CLAY

An integrated analysis of a jack-up platform and its soil foundation system may increase the overall bearing capacity and provide more favourable structural response compared to a conventional analysis based on pinned footing condition. A model for the cyclic force-displacement and moment-rotation relationships of a spud can on stiff clay is presented. The model takes into account the effects of the loading history (degradation during cyclic loading), strain rate, strength anisotropy and non-linear stress-strain relationship of the clay, and coupling between all force-displacement components. It is valid for all load levels, including the combination of the static vertical load due to the submerged weight of the platform and cyclic forces (due to waves, wind and current) that cause failure of the spud can. The model performance is illustrated by an analysis of a jack-up platform at a deep water site. The results are compared with those based on the pinned footing condition and a maximum lower bound solution of the overall bearing capacity of the platform.(