Traction-based implementation of transmitting boundaries for nonlinear seismic Soil-Structure interaction analyses

This paper introduces a straightforward traction-based approach for implementing transmitting boundaries in time-domain nonlinear seismic soil-structure interaction (SSI) analyses. The primary objective is to simplify the challenges associated with integrating appropriate boundaries into finite-element analysis software. The proposed method conceptualizes an SSI model as a free body extracted from its original domain and determines the boundary traction (i.e., stress boundary conditions in the engineering sense) at the cutting surface. This determination is based on the current velocity, free-field dynamic responses, and static equilibrium stresses. In scenarios employing the classic viscous boundary, traction is solely dependent on the free-field dynamic responses and static equilibrium stresses, facilitating predetermined calculations. Detailed implementation guidelines for Abaqus are provided to illustrate the practicality of the proposed technique. The efficacy of this technique was validated by its ability to accurately reproduce both linear and nonlinear one-dimensional shear waves in threedimensional models. Furthermore, the nonlinear responses of the SSI models with varying soil dimensions underscored the effectiveness of the approach for domain reduction.