Transient response in steel moment frames caused by brittle connection fracture |
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| Authors: | Janise E Rodgers Stephen A Mahin |
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| Institution: | 1. GeoHazards International, Palo Alto, CA, U.S.A.;2. Project Manager.;3. University of California, Berkeley, CA, U.S.A.;4. Byron and Elvira Nishkian Professor of Structural Engineering. |
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| Abstract: | Brittle fractures occurring at the beam–column connections of welded steel moment frames, such as those observed following the Mw 6.7 1994 Northridge earthquake, result in sudden decreases in connection strength and stiffness. These changes lead to various types of transient dynamic behavior at the local and global levels. The effects on global acceleration include highly transient, high‐frequency waveforms that occur immediately following fracture and decay quickly. The theoretical basis for the occurrence of these transient waveforms is examined and their presence in structural analysis results is demonstrated. Results from shaking table experiments on a simple steel moment frame with fracturing connections show that transient accelerations are consistently observed following fracture. These experiments and analyses show that, due to their short duration, the transient acceleration waveforms do not cause any sudden changes in the global lateral displacement response of typical building structures. Therefore, these global acceleration transients have relatively benign effects on overall system behavior despite their relatively large amplitudes. Copyright © 2007 John Wiley & Sons, Ltd. |
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| Keywords: | steel moment frames fracture acceleration high frequency earthquake engineering |
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