In this study, a three-dimensional microscale framework utilizing the discrete element method (DEM) is presented to analyze the energy dissipation mechanisms during seismic loading of a soil-foundation-structure system. The granular soil deposit is idealized as a collection of spherical particles using DEM. The foundation is modeled as a rigid block composed of clumped particles and its motion is described by the resultant forces and moments acting upon it. The structure is modeled as a column made of particles that are either clumped to idealize a rigid structure or bonded to simulate a flexible structure of prescribed stiffness. Analysis is done in a fully coupled scheme in time domain. Energy dissipation inside the soil deposit was characterized based on a microscale approach. Dissipated energy is found to be confined to a limited zone in the immediate vicinity of the foundation. Energy dissipation pattern is affected by the amplitude and frequency of the input motion, foundation embedment, and structure stiffness.
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