Undrained capacity of circular shallow foundations under combined VHMT loading

Torsional loads can be significant on shallow foundations for large onshore structures, such as wind turbines. However, torsional effects for circular foundations under a zero-tension interface condition have not been well studied. This paper shows the results of finite element analysis of circular foundations with a no-tension interface under combined vertical, horizontal, moment and torsional loading. Similar equations to current forms of V-H expression are applied to model the V-T relationship. The normalized H-T and M-T envelopes have been simulated with existing analytical equations, but with some modifications. The developed approaches will provide improved design methods for estimating torsional capacity of shallow foundations.