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Spectrum analyses of strong-motion earthquakes

Alford, Jack L. and Housner, George W. and Martel, R. R. (1964) Spectrum analyses of strong-motion earthquakes. California Institute of Technology . (Unpublished)

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The problem of the dynamic response of a structure to an earthquake has been formulated in a manner which permits separation of the characteristics of particular structures from the characteristics of the earthquake. The expression involving the characteristics of the earthquake is defined as the "spectrum" of the earthquake and it is shown that the spectrum is simply a plot of the response of a simple oscillator versus the period of the oscillator. Eighty-eight such spectra were computed by means of an electric analog computer and are presented in this report. It is found that damping is a very important parameter in the overall problem; relatively small amounts of damping reduce structural response sharply. It is shown that, when damping is considered, the spectra are consistent with the hypothesis of a distribution about a mean value. It is concluded that the concept of a "dominant ground period" is not valid for the purpose of aseismic structural design. Further research on damping in buildings is recommended, and it is proposed that the mean value of a damped spectrum be used as a quantitative measure of earthquake intensity.

Item Type:Report or Paper (Technical Report)
Additional Information:Report on research conducted under contract with the Office of Naval Research. Originally published August 1951. This is "revised August 1964".
Group:Earthquake Engineering Research Laboratory
Record Number:CaltechEERL:1964.EERL.1964.001
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Usage Policy:You are granted permission for individual, educational, research and non-commercial reproduction, distribution, display and performance of this work in any format.
ID Code:26476
Deposited By: Imported from CaltechEERL
Deposited On:19 Feb 2008
Last Modified:03 Oct 2019 03:15

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