A Macro-Element Model for Spudcan Foundations in Clay Overlying Sand

A macro-element model for predicting spudcan foundations behaviour for jack-up units in clay overlying sand under combined vertical, horizontal, and moment loading is introduced. Geotechnical centrifuge tests that measured the effect of the underlying sand layer on the foundation behaviour are combined with finite-element analyses and theoretical developments to derive the model. The results reveal that as the spudcan nears the sand layer, the absolute horizontal capacity remains relatively constant, while the vertical and moment capacities increase at approximately the same normalised rate. An increased pushover capacity of jack-up units is demonstrated by integration of the model into structural analysis.