Apparent Periods of a Building. II: Time-Frequency Analysis
Publication: Journal of Structural Engineering
Volume 127, Issue 5
Abstract
In this, the second of a two-part paper, the analysis of the apparent frequency of a seven-story reinforced-concrete hotel building in Van Nuys, Calif., is extended to consider its time-dependent changes, both short and long term. The instantaneous apparent frequency is measured by two methods: windowed Fourier analysis and zero-crossings analysis. The results show that it changes from earthquake to earthquake and during a particular earthquake. The results also suggest “self healing” believed to result from settlement of the soil with time and dynamic compaction from aftershock shaking. Implications of such high variability of the system frequency on structural health monitoring, control of response, as well as on the design codes are discussed. Nonlinear response of the foundation soil acts as a sink of the incident seismic wave energy. It is suggested that it could be exploited in future designs to serve as a powerful and inexpensive energy-dissipation mechanism.
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Information & Authors
Information
Published In
Journal of Structural Engineering
Volume 127 • Issue 5 • May 2001
Pages: 527 - 537
History
Received: Feb 22, 2000
Published online: May 1, 2001
Published in print: May 2001
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