Two centrifuge tests were performed at the University of Colorado Boulder to fundamentally evaluate site performance and soil-foundation-structure-interaction (SFSI) on uniform, medium-dense, saturated sand undergoing a range of broadband earthquake motions with different characteristics. The test results were also used to evaluate and quantify the capability of a state-of-the-art numerical tool in capturing the key response parameters of interest, such as excess pore pressures, accelerations, and settlements at key locations. In this paper, the experimentally measured and numerically computed excess pore pressures and accelerations within the soil in free-field and under the foundation are compared, showing reasonable agreement (with residuals in spectral accelerations and Arias Intensities ranging from -1.5 to 1). Neither experimental nor numerical results indicated a decrease in foundation accelerations compared to the free-field soil at higher frequencies, which is due to a larger degree of excess pore pressure generation and strength loss in the free-field compared to the soil under the confining pressure of the structure.
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