Seismic Retrofit of Reinforced Concrete Moment Frame Using a BRB with U-Plate Connections
Publication: Journal of Structural Engineering
Volume 148, Issue 9
Abstract
Since their first use in 1989, buckling-restrained braces (BRBs) have proven to be an efficient energy dissipation device. Two reduced scale quasi-static cyclic experiments were conducted for a reinforced concrete (RC) moment frame with substandard seismic details retrofitted with a BRB to examine its performance. In the first experiment, the BRB was attached to the RC frame utilizing post-installed U steel plates designed using the uniform force method. The RC frame was tested utilizing the BRB retrofit until the BRB steel core fractured in tension, at which point the BRB was removed. A second experiment was carried out on the damaged RC frame, following removal of the BRB, with the U steel plates still attached. The two experiments showed that the RC frame retrofit using a BRB and U steel plates is an effective approach to doubling the strength, stiffness, and total hysteretic energy dissipation of the original RC frame with substandard seismic details. In addition, a method of proportioning the seismic retrofit components, including the size of the BRB and U steel plates, is developed. Nonlinear pushover and cyclic analyses were used to compare the experimental results to OpenSees numerical models.
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Data Availability Statement
Some or all data, models, and code that support the findings of this study are available from the corresponding author upon reasonable request.
Acknowledgments
The research presented here was supported by CoreBrace, LLC, and the University of Utah. Any opinions, findings, conclusions, or recommendations expressed in this paper are those of the authors. The authors acknowledge the assistance of M. Bryant, C. Murphy, V. McEntee, D. Thapa, D. Tran, and I. Dangol of the University of Utah for their assistance in carrying out the experiments. The authors would like to acknowledge helpful discussions with Brandt Saxey of CoreBrace LLC.
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Published In
Journal of Structural Engineering
Volume 148 • Issue 9 • September 2022
Copyright
© 2022 American Society of Civil Engineers.
History
Received: Jul 9, 2021
Accepted: Mar 28, 2022
Published online: Jun 25, 2022
Published in print: Sep 1, 2022
Discussion open until: Nov 25, 2022
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