Gapped-Inclined Braces for Seismic Retrofit of Soft-Story Buildings
Publication: Journal of Structural Engineering
Volume 140, Issue 11
Abstract
Although soft-story mechanisms are generally undesirable for the seismic response of building structures, they provide potential benefits caused by the isolating effect they produce for the stories located above. In this paper, an approach for enhancing the seismic response of soft-story structures is proposed that takes advantage of the positive aspects of their response while mitigating the negative ones. To this end, an additional gapped-inclined brace (GIB) is introduced to reduce the impact of P-Delta effects on the displacement demands and to increase the deformation capacity of existing columns in soft stories without significantly increasing their lateral resistance. The mechanics of the proposed system are first defined, and theoretical relations and numerical models are then derived to verify the response. The cyclic behavior of a single-degree-of-freedom single-bay RC frame is then investigated numerically to illustrate the effect of the retrofitted system on the global response of a structure. The analytical results indicate that the hysteretic response of the retrofitted system is highly improved in terms of the energy dissipation and the residual deformation while not significantly increasing the overall strength of the structure. Although the equations governing the response of the system are derived for a single story, the concept is primarily intended to be applicable to multistory buildings.
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Acknowledgments
The authors gratefully acknowledge the support offered by the University of Toronto and the ROSE program at the UME School, IUSS Pavia.
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Published In
Journal of Structural Engineering
Volume 140 • Issue 11 • November 2014
Copyright
© 2014 American Society of Civil Engineers.
History
Received: May 27, 2013
Accepted: Nov 13, 2013
Published online: May 19, 2014
Discussion open until: Oct 19, 2014
Published in print: Nov 1, 2014
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