Optimization of Two Soil–Structure Interaction Parameters Using Dynamic Centrifuge Tests and an Analytical Approach

The response of the structure subjected to an earthquake load is greatly affected by the properties of the structure and soil so it is very important to accurately determine the characteristics of the structure and soil for analysis. However, studies on the effective profile depth where soil properties are determined, have been conducted in the presence of restricted conditions (i.e., surface foundation, linear soil properties), and without any considerations on damping. In case of the effective height of structure that affects its rocking behavior, it was only theoretically or empirically determined. In addition, most previously published studies on soil–structure interaction (SSI) focused on limited effects and parameters (e.g., rocking behavior, embedment effect, effective profile depth, spring constant, and damping coefficient) and not on comprehensive SSI parameters. Furthermore, no detailed validation procedure has been set in place which made it difficult to validate the SSI parameters. Since the effective height of structure and effective profile depth are the basis of all the input parameters of SSI analysis, it is important to validate and determine them. Therefore, in this study, the procedure used to optimize the two SSI parameters was established based on an analytical approach that considered all the possible SSI parameters that were investigated from conventional codes and studies and physical model tests. As a result of this study, the optimum values of the effective height of the structure and effective profile depth were respectively determined according to (a) the height from the bottom part of the foundation to the center of the mass of the superstructure, and according to (b) the depth at values equal to four times the radius of the foundation.