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Frequency‐independent impedances of soil‐structure systems in horizontal and rocking modes
Author(s) -
GhaffarZadeh Mansour,
Chapel François
Publication year - 1983
Publication title -
earthquake engineering and structural dynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.218
H-Index - 127
eISSN - 1096-9845
pISSN - 0098-8847
DOI - 10.1002/eqe.4290110406
Subject(s) - parametric statistics , soil structure interaction , electrical impedance , harmonic , excitation , foundation (evidence) , mathematics , homogeneous , engineering , mathematical analysis , structural engineering , finite element method , physics , acoustics , statistics , electrical engineering , archaeology , combinatorics , history
The frequency‐independent foundation impedances, commonly used in soil‐structure dynamic interaction problems, are developed for a circular footing resting on a homogeneous halfspace. As they ignore the structure attached to the foundation, the error introduced in the structural response may be 50 per cent or more in the neighbourhood of the fundamental frequency of the soil‐structure system. The present study proposes a new method developed for most dynamic soil‐structure interaction problems. The key idea is to retain for the frequency‐independent impedances values computed for the fundamental frequency of the soil‐structure system; thus these values include the dynamic characteristics of the whole soil‐structure system and lead to a satisfactory approximation of the exact solution over a wide frequency range. The method is developed here for the horizontal and rocking modes of a structure with a circular base resting on a homogeneous halfspace. Numerical applications are given for a simple linear oscillator in order to make possible a thorough parametric study. The response of some idealized building‐foundation systems to harmonic excitation or to a seismic input is next examined in order to illustrate the efficiency of the proposed model.