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Conference Article: Dynamic-stiffness matrix of surface foundation layered halfspace based on stiffness-matrix approach

Wolf, J.P.; Darbre, G.R. (Electrowatt Engineering Services, Ltd., Zurich, Switzerland)

Abstract

The dynamic-stiffness matrix of the soil appears in the basic equation of motion of the analysis of soil-structure interaction based on the substructure method. This matrix specifies the amplitudes of the forces due to displacements of unit amplitude that are applied at the nodes of the structure-soil interface for harmonic motion. The structure-soil interface of arbitrary shape can be flexible or rigid. Only structures supported on the surface of a layered soil are examined. The soil consists of horizontal layers of visco-elastic material with hysteretic damping which rest on a halfspace with the same material characteristics. The dynamic-stiffness matrix is derived using the boundary-integral method. Its discretized form is the so-called boundary-element method. It requires the evaluation of the flexibility-influence functions (Green functions) of the layered site which are calculated as integrals in the wave-number domain. The dynamic-stiffness coefficients are given for a rigid disc as a function of frequency for a visco-elastic halfspace, a single layer resting on a halfspace and a single layer built-in at its base. The corresponding two-dimensional cases are also examined. Replaced and welded contacts are analyzed. The influence of material damping is also investigated.

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key words: Gas Cooled Reactor, Nuclear Technology
Reference:
IAEA IWGGCR specialists' meeting on gas-cooled reactor seismic design problems and solutions. San Diego, CA (USA). 30 Aug - 1 Sep 1982
International Atomic Energy Agency, Vienna (Austria).
IWGGCR--6, pp:183-206