Soil-structure interaction and its roles in performance-based seismic analysis of shear wall structures

In order to systematically assess the complex soil-structure interaction (SSI) effects on the seismic responses of shear wall structures, this dissertation deals with several critical and inter-related topics under the framework of performance-based earthquake engineering.;Firstly, the study develops improved pulse representations for earthquake ground motions that govern the peak structural responses. Based on rigorous dimensional analysis, the dimensionless H-response spectra are derived for both linear and bilinear SDOF systems. They are shown to be congruent with the corresponding (dimensional) response spectrum in bi-logarithmic plotting. This leads to a novel approach to identify pulse parameters that match simultaneously the kinematic characteristics and the response spectrum of the original ground motion. The improved pulse representations can potentially be used as the intensity measures of earthquake ground motions.;Secondly, the SSI effects of lumped soil-foundation-structure interacting (SFSI) systems are investigated through the dimensional analysis with pulse motions as input. The dimensionless terms that govern the interactive behavior of SFSI systems are derived. The SSI effects are related explicitly and directly to the characteristics of input ground motions and the properties of SFSI systems. The conditions under which the SSI effects amplify or reduce the structural responses are also identified.;Subsequently, dynamic responses of strip foundations bonded on linear or nonlinear soil half-space are investigated using the finite element method. The dynamic foundation responses are found to depend on the amplitude and frequency of input motion, foundation geometry, and soil properties. The energy dissipation through radiation damping for nonlinear soil case is reduced and can be quantified with two alternative factors related to the yielding of soil medium.;Finally, the SSI effects are evaluated for a realistic shear wall structure using the probabilistic seismic demand analysis where the nonlinear hysteretic behavior of shear walls and foundations are accurately modeled. Either the inelastic spectral displacement or the pulse representation is adopted as the intensity measure of input ground motions. The damage probability of the shear wall generally decreases when the SSI effects are considered for this case study.