Stress-independent parameters for stress-strain relationship and damping in nonlinear one-dimensional seismic site response analysis

Abstract

The modulus reduction and damping curves represent the nonlinear behavior of soil under cyclic load. In the literature, those curves were produced from lab tests of soil at particular confining stresses. This study developed a set of parameters that can be used to normalize the modulus reduction and damping curves to be stress-independent. The proposed formulations for the stress-independent parameters were implemented in the finite element code SRAP and validated through producing shear modulus reduction and damping curves that match the existed ones. Nonlinear 1D seismic site response analyses were conducted for centrifuge experiments to verify the developed computer code. Comparisons of the analysis results between SRAP and another computer code were presented in terms of maximum and minimum displacement, peak ground acceleration, maximum shear strain profiles, and response spectra.

Keywords:

backbone curve; hysteretic damping; dynamic soil model; stress-independent parameters; finite element method; nonlinear 1D seismic site response analysis.