Accession Number : AD0469600

Title :   VERTICAL MOTION OF RIGID FOOTINGS.

Descriptive Note : Final rept.,

Corporate Author : MICHIGAN UNIV ANN ARBOR COLL OF ENGINEERING

Personal Author(s) : Lysmer, John

Report Date : JUN 1965

Pagination or Media Count : 137

Abstract : This work deals with the vertical mode of vibration of a rigid circular footing resting on a plane soil surface and excited by a vertical time-dependent force in the axis of symmetry. It is assumed that the subsoil can be considered as a perfectly elastic, isotropic, and homogeneous half space. First an approximate theoretical solution is developed for the steadystate motion of the above half-space model. This solution differs from previously published solutions in that it includes all frequencies of excitation. It is then shown how the transient response due to a pulse-type loading can be calculated from the steady-state solution by a simple Fourier technique, and a computer program using this technique is presented. Parallel with the above development it is shown that the elastic half-space model behaves very similarly to a simple damped oscillator, and the author proposes the use of a simplified analog of the mass-spring-dashpot type for practical calculations. The above theoretical results are supported by the presentation of both steady-state and impact tests performed by other researchers. (Author)

Descriptors :   (*STRUCTURES, SUPPORTS), (*SUPPORTS, VIBRATION), MOTION, SOILS, PRESSURE, EQUATIONS, MATHEMATICAL ANALYSIS.

Distribution Statement : APPROVED FOR PUBLIC RELEASE