Dr. Villalobos-Jara, Felipe

In this work, a coupled macroelement model for shallow foundations under cyclic loading has been developed. Coupling a hypoplastic constitutive model with an uplift plasticity model and a Mohr-Coulomb interface model can substantially improve the prediction of the foundation response. The yield surface adopted in this work is an ellipsoid and the flow rule can be chosen associated or non-associated. The couplings are achieved by introducing new variables that control the dominance of one model on the total response. Initial validation is carried out against numerical FEM simulations for shallow foundations in loose and dense sand subjected to monotonic and symmetric cyclic loading. Further validation against experimental data is performed by comparing the results obtained from caisson foundations in loose and dense sand subjected to non-symmetric and symmetric cyclic loading. The proposed macroelement model shows satisfactory results because it captures not only the limit loads, loading and unloading stiffness of load-displacement curves, but also complex cyclic settlement variations, in particular foundation uplift.