Seismic Soil–Structure Interaction Analysis of Concrete Gravity Dam Using Perfectly Matched Discrete Layers with Analytical Wavelengths

Abstract

ABSTRACT For heavy structures like concrete gravity dams, soil–structure interaction has a great effect on the structural behavior. One of the important features of soil–structure interaction problems is absorbing boundary conditions for the unbounded soil domain. In this study, perfectly matched discrete layers with analytical wavelengths (AW-PMDLs), which was developed recently by the authors, is applied to concrete gravity dam analyses. Free-field motions during earthquakes with the presence of absorbing boundary conditions need to be included. A Free-field element is presented to take into account the free-field motions. The hydrodynamic pressure from the reservoir to the dam is introduced by using Westergaard added mass method. A procedure with the combination of the AW-PMDL elements, Free-field elements, and Westergaard added masses is proposed to analyze concrete gravity dams considering soil-–structure interaction. For the sake of numerical analyses, AW-PMDLs, Free-field elements, and Westergaard added masses are implemented by using user-defined elements (UEL) in ABAQUS. The validation of the proposed procedure is made by comparing the results with a previous study and the results obtained from SASSI, a program used to analyze the soil–structure interaction problems in the frequency domain. Then, the linear and nonlinear analyses of the dam system are observed for various soil stiffness. It can be seen that the nonlinear analyses need to be considered for a rigorous dam structure analysis.