Determination of soil impedance functions from vibration-test response of a circular foundation / Détermination des fonctions d'impédance du sol à partir de la réponse d'une fondation circulaire lors d'essais de vibration

The paper presents the results of the determination from vibration tests of impedance functions for a concrete basemat of a one-quarter scale model of a nuclear power-plant containment building. Comparison of the test-determined modal characteristics with corresponding analytical ones based on the Lysmer analog shows that though the latter gives natural-frequency estimates of the right order of magnitude, it does not give acceptable estimates of the damping coefficient. Analytical impedance functions based on a model of rigid-plate on an elastic half-space were found to have the same trend as the test-determined ones at lower frequencies, but not at higher frequencies.