Bearing Capacity of Pile Groups under Generalized Loading Condition

Recently new criteria have been proposed to assess the failure envelopes of the foundation in the force space which are referred to as interaction diagrams. For vertical eccentric loads, these can be constructed using an exact solution based on theorems of the limit analysis accounting for the direction of the resulting moment vector. In case of horizontal loads, the available approximate solution is derived from the limit equilibrium method and incorporates the dependence of the yielding moment of the pile concrete cross-section from the axial force acting at its head. When compared with conventional criteria, these recent methods offer undeniable advantages in the design of pile foundations. Nevertheless, the interaction between the horizontal and moment components has not yet been properly implemented in routine design and may lead to an overestimation of the collapse load when the sectional moment capacity of the piles is not negligible. To fill this gap, an approach based on the limit equilibrium method to construct the collapse domains in the force space is proposed, in which the interaction mechanisms between the components of the resulting load are fully addressed. An application to the case study of a real pile group is also presented.