Strongback System: A Way to Reduce Damage Concentration in Steel-Braced Frames
Publication: Journal of Structural Engineering
Volume 141, Issue 9
Abstract
This paper examines a newly developed seismic force-resisting system: the strongback system (SBS). To achieve improved seismic performance, this system combines aspects of a traditional concentric braced frame with a mast to form a hybrid system. The mast acts like a strong back to help resist the tendency of concentric braced frames to concentrate damage in one or a few stories during severe seismic excitations. The purpose of the strongback system is to promote uniform story drifts over the height of a structure. Three SBS prototypes were designed and analyzed considering a variety of earthquake excitations. Computed responses are compared with responses for three other braced frame systems. Results of quasi-static inelastic analyses, both monotonic and cyclic, are presented to demonstrate differences in the fundamental hysteretic behavior of the braced frame systems considered. A series of nonlinear dynamic response history analyses were then performed to compare the global and local dynamic response of each system. Results show that the SBS can effectively reduce the concentration of deformations using the proposed design strategy. Simplified cost analyses demonstrated the economic feasibility of incorporating the SBS for newly constructed buildings located in seismically active regions.
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Acknowledgments
This research is supported by National Science Foundation (NSF) under grant number CMMI-0619161: International Hybrid Simulation of Tomorrow’s Braced Frame Systems. Financial support from NSF is greatly appreciated. The conclusions and opinions expressed in this paper are those of the authors and do not necessarily represent the views of the sponsor.
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Published In
Journal of Structural Engineering
Volume 141 • Issue 9 • September 2015
Copyright
© 2014 American Society of Civil Engineers.
History
Received: Apr 14, 2014
Accepted: Sep 25, 2014
Published online: Nov 6, 2014
Discussion open until: Apr 6, 2015
Published in print: Sep 1, 2015
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