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Soil‐structure interaction for tower structures
Author(s) -
Warburton G. B.
Publication year - 1978
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.4290060603
Subject(s) - beam (structure) , natural frequency , normal mode , vibration , cantilever , soil structure interaction , modal analysis , physics , harmonic , half space , excitation , displacement (psychology) , mechanics , structural engineering , geometry , mathematics , finite element method , engineering , optics , acoustics , psychology , quantum mechanics , psychotherapist
The soil‐structure system is modelled as a uniform vertical beam, which terminates in a base or foundation mass; this mass is attached to the surface of an elastic half‐space. Using known force‐displacement relations for the coupled vibrations of a rigid disc on an elastic half‐space, the natural frequencies and response to a transverse harmonic force, applied at the tip of the beam, are determined through a continuum approach. Effectively the problem reduces to a beam with frequency‐dependent boundary conditions. A parametric study shows that changes in the three ratios, Young's modulus for the beam to that for the half‐space, the radius of the base mass to the length of the beam, L , and the second moment of area of the beam cross‐section/ L 4 , cause large variations in the maximum response, which due to interaction can be considerably smaller or larger than that for a comparable fixed‐base cantilever beam. This dynamic behaviour can be explained by considering the variation of natural frequencies, mode shapes and modal damping factors with these ratios. A brief study of the response of the structure to a free‐field harmonic acceleration, applied at the soil‐structure interface, suggests that interaction depends upon material and geometric properties of the system, rather than on the nature of the excitation.