Flexural Retrofit of Support Regions of Reinforced Concrete Beams with Anchored FRP Ropes Using NSM and ETS Methods under Reversed Cyclic Loading
Publication: Journal of Composites for Construction
Volume 21, Issue 1
Abstract
Many studies have been carried out on enhancing the positive moment capacity of the midspan areas of RC beams with fiber-reinforced polymer (FRP) reinforcement under monotonic increasing loads. The present study focuses on retrofitting of beam support regions under reversed cyclic loading conditions representing seismic conditions. The tests were conducted on seven full-scale RC beam-column-slab subassemblages with a part of transverse beams perpendicular to the main beam. The specimens were divided into three series that represented different geometrical characteristics of beams and columns in frames such as wide beam–narrow column, narrow beam–wide column, and beam and column of equal widths. One reference specimen in each series was tested as is, while the remaining four specimens were tested after being retrofitted with near surface–mounted (NSM) carbon fiber–reinforced polymer (CFRP) ropes. Two different retrofitting details in terms of anchorage of CFRP ropes at the support region were applied [NSM and embedded through-section (ETS)] and their effectiveness is investigated. Furthermore, the validity of design code formulations currently available for near surface–mounting method is investigated and a modification is proposed to consider the effects of cyclic loading conditions. The results show that the retrofitted beams achieved an enhancement in the moment capacity but it could not be sustained at large deformations due to weakening of bond between concrete and adhesive under cyclic actions and localization of cracks at the maximum moment zone.
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Acknowledgments
The financial support of the Scientific and Technological Research Council of Turkey (TUBITAK) Grant No. 113M112 and Scientific Research Projects Unit of Istanbul Technical University (ITU-BAP) are gratefully acknowledged. The authors thank Boler Celik for modifying the test setup and SIKA in particular to Mr. Berset for his advice and support for providing the CFRP ropes and retrofit application. The authors specially thank Yavuz and Derya Cavunt for their precious help throughout the experimental study. The authors also acknowledge the technical staff at the Structural and Earthquake Engineering Laboratory (STEEL) of Istanbul Technical University (ITU) for their invaluable contributions during the experimental study.
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Published In
Journal of Composites for Construction
Volume 21 • Issue 1 • February 2017
Copyright
©2016 American Society of Civil Engineers.
History
Received: Jan 31, 2016
Accepted: May 25, 2016
Published online: Jul 11, 2016
Discussion open until: Dec 11, 2016
Published in print: Feb 1, 2017
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