Beam-on-Nonlinear-Winkler-Foundation Modeling of Shallow, Rocking-Dominated Footings

Abstract

The nonlinear behavior of shallow foundations under large amplitude earthquake-induced loading can result in dissipation of seismic energy through the mechanism of soil yielding beneath the foundation. In addition, foundation uplifting may shift the period of the soil-foundation-structure system away from the damaging energy content of most earthquakes. However, this yielding and uplifting may lead to excessive transient and permanent deformations (settlement, rocking, and sliding). Therefore, modeling procedures that account for foundation nonlinearity and uplift are needed before these benefits can be realized in performance based earthquake engineering (PBEE) practice. This paper adopts a beam-on-nonlinear-Winkler-foundation (BNWF) simulation methodology for modeling shallow foundation-structure systems, where seismically-induced rocking plays a predominant role in their response. Numerical results demonstrate that reasonable comparison between the nonlinear Winkler-based approach, and experimental response in terms of moment-rotation, settlement-rotation, and shear-sliding displacement can be obtained, given an appropriate selection of model and soil properties.