Earthquake Response of Building-Foundation Systems
<p>The influence of a deformable foundation on the response of buildings to earthquake motion is examined. The study is divided into two parts; the vibration of the base of the building on the foundation medium, and the response of the whole building-foundation system.</p> <p...
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| Format: | Others |
| Language: | en |
| Published: |
1971
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| Online Access: | https://thesis.library.caltech.edu/10591/2/Bielak_J_1971.pdf Bielak, Jacobo (1971) Earthquake Response of Building-Foundation Systems. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/YEAJ-FN27. https://resolver.caltech.edu/CaltechTHESIS:12062017-133056313 <https://resolver.caltech.edu/CaltechTHESIS:12062017-133056313> |
| Summary: | <p>The influence of a deformable foundation on the response of
buildings to earthquake motion is examined. The study is divided into
two parts; the vibration of the base of the building on the foundation
medium, and the response of the whole building-foundation system.</p>
<p>Studied first are the forced horizontal, rocking and vertical
harmonic oscillations of a rigid dis c bonded to an elastic half-space, which
is considered as a mathematical model for the soil. The problem,
formulated in terms of dual integral equations, is reduced to a system
of Fredholm integral equations of the second kind. For the limiting
static case these equations yield a closed form solution in agreement
with that obtained by others.</p>
<p>Using the force-deflection relations for the base, the equations of
motion of linear building-foundation systems are solved by both direct
and transform methods. It is shown that, under assumptions which
appear to be physically reasonable, the earthquake response of the interaction
system reduces to the linear superposition of the responses of
damped, linear one-degree-of-freedom oscillators subjected to modified
excitations. This result is valid even for systems that do not possess
classical normal modes. Explicit approximations in terms of the parameters
of the system are obtained for the dynamic properties of
the one-degree-of-freedom oscillator which is equivalent to a single story
building-foundation system. For multi-story buildings it is shown that the
effect of an elastic foundation, as measured by the change in
the natural frequencies of the building, is negligible for modes
higher than the first for many types of building structures.</p>
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