NUMERICAL SIMULATION OF MODEL TESTS OF PIER-SHALLOW FOUNDATION SYSTEMS SUBJECTED TO EARTHQUAKE LOADS USING AN ELASTO-UPLIFT-PLASTIC MACRO ELEMENT

A dynamic analysis model for the nonlinear behavior of a shallow foundation subjected to seismic loads is developed. A macro-element approach is revised assuming elasto-uplift-plastic behavior, in which uplifting and coupling effects of vertical, horizontal, and moment loads are taken into account. Large-scale shake table experiments of model pier footings are also conducted and simulated using the revised macro-element model. The numerical result reveals that the shape of the hysteresis loops for coupled load-displacement relationships is predicted very well, including the effects of uplift. In addition, the revised model can account for settlement with some inclination that has accumulated during the excitation.