Seismic Interaction Among Numerous Masses Founded on a Viscoelastic Stratum

Adams, Teresa M.; Christiano, Paul; ,

Seismic Interaction Among Numerous Masses Founded on a Viscoelastic Stratum

by Teresa M. Adams, Carnegie-Mellon Univ, Pittsburgh, PA, USA,
Paul Christiano, Carnegie-Mellon Univ, Pittsburgh, PA, USA,

Document Type: Proceeding Paper

Part of: Recent Applications in Computational Mechanics

Abstract:

The steady-state harmonic response of systems comprising numerous masses resting on a homogeneous, viscoelastic stratum with hysteretic damping is studied. The stratum, bearing on a rigid base, is treated as an unbounded continuum in the horizontal direction. The mass-stratum system is excited by vertically propagating harmonic waves which induce vertical and horizontal free-field ground motion. Attention is focused on the responses of a cluster of circular masses such as would exist in a typical farm of liquid storage tanks. Interaction among the masses is accounted for by coupling the degrees of freedom of each mass in the system impedance matrix. Results indicate that interaction among the masses causes multiple soil-structure resonant responses that generally are greater than for an isolated single mass. Even for rather widely spaced masses, amplification at second and third soil-structure resonant frequencies may be significantly higher than magnification at the first soil-structure resonant frequency. The fundamental resonant frequency and some higher resonant frequencies may be predicted on the basis of one-dimensional longitudinal and shear vibration of the layer-mass system.

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