Experimental Calibration and Verification of Equivalent Linear Models for Intrinsic Damping in Soil-Structure Dynamics

The dynamic mechanical properties of geotechnical and structural construction materials are often vastly different. The differences in these properties must be preserved when analyzing a composite soil-structure infrastructure system. In this paper, we present preliminary data and a program of study focused on the experimental calibration and verification of two equivalent linear modeling procedures for representing the effects of unique soil and structural damping properties upon overall dynamic system behavior. The investigated procedures involve linear hysteretic and Kelvin-Voigt constitutive models. Multiple dry sands' strain-dependent damping ratio curves are experimentally determined through resonant column procedures and compared against empirical relationships. These strain-dependent curves, along with stiffness degradation curves, are fed into substructured, frequency-domain, finite element models for a series of six dynamic soil-structure systems. The six systems involve increasing complexity in the variability of damping properties and each of the six models is analyzed using both aforementioned modeling techniques. The future progress of this study will involve the six dynamic soil-structure systems being replicated and instrumented as small-scale, geotechnical centrifuge models in order to calibrate and determine the validity of the two equivalent linear procedures in preserving distinct dissipative characteristics of multiple materials.