Pushover Response of a Braced Frame with Suspended Zipper Struts
Publication: Journal of Structural Engineering
Volume 134, Issue 10
Abstract
This paper presents the results from an experimental pushover test on a one-third-scale model of a special inverted-V-braced steel frame with zipper struts. Zipper elements are vertical elements added at the intersections of the braces above the first floor and designed to carry upward the unbalanced loads resulting from buckling of the braces. As far as the writers know, this is the first test on such a configuration that has been suggested as an alternate to conventional braced frames in the American Institute of Steel Construction seismic specification for many years. The model was pushed to a target roof drift ratio of , which was achieved without strength degradation and followed a trilinear backbone curve. The load was then reversed until the bottom story brace in tension fractured at a drift of . After this fracture, the frame still carried about 37% of the maximum base shear. The zipper elements demonstrated their ability to activate buckling in all stories except the top one, redistributing the loads in the structure and minimizing strength losses. Two-dimensional and one three-dimensional frame models were analyzed and found to reproduce satisfactorily the experimental results up to the beginning of tearing in the tension brace.
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Acknowledgments
This work is being carried out under NSF Grant No. 0324542 to Georgia Tech. The opinions given and results described herein are the exclusive responsibility of the senior writer and do not reflect the views of any of the universities involved, nor the National Science Foundation. This project is part of a pre-NEESR collaborative project with the University at Buffalo (Dr. A. Reinhorn and M. Schacter), the University of California at Berkeley (Dr. Stojadvonivic and T. Yang), the University of Colorado at Boulder (Dr. B. Shing and A. Stavridis), and Florida A&M (Dr. A. Makollah).
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Information & Authors
Information
Published In
Journal of Structural Engineering
Volume 134 • Issue 10 • October 2008
Pages: 1619 - 1626
Copyright
© 2008 ASCE.
History
Received: Sep 27, 2006
Accepted: Mar 21, 2008
Published online: Oct 1, 2008
Published in print: Oct 2008
Notes
Note. Associate Editor: James S. Davidson
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