Plastic Hinge Length of FRP-Confined Square RC Columns
Publication: Journal of Composites for Construction
Volume 18, Issue 4
Abstract
The confinement effect of fiber-reinforced polymer (FRP) jacket on the plastic hinge length of square RC columns is studied through experimental testing and analytical study. Seven half-scale RC square columns with different confinement ratios were tested. The strain of longitudinal reinforcement bars and the extent of yielding were measured by strain gauges mounted inside the reinforcement bars. The variation of the strain field of the external column face was recorded continuously by digital image correlation (DIC) during a test. More rational approaches of data analysis are used for identification of plastic hinge length from measured strain fields. The obtained results show that compared with unconfined RC columns, FRP jacketing increases the plastic hinge length when the confinement level is low, but reduces it when the confinement level is high. The analytical study shows that all existing models of plastic hinge length are inadequate in one way or another because no model includes all important factors. The proposed model can correctly capture the trends but it needs to be further improved for accuracy when more data are available.
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Acknowledgments
Cheng Jiang was financed by a grant from the Research Grants Council of the Hong Kong Special Administrative Region, China (Project No. CityU 123711). The experimental work was supported by an open project of Key Laboratory of Concrete and Prestressed Concrete Structures of the Ministry of Education, Southeast University, China (Project No: CPCSME2010-05), with supplemental fund from National Natural Science Foundation of China (Project No. 51178099).
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Published In
Journal of Composites for Construction
Volume 18 • Issue 4 • August 2014
Copyright
© 2014 American Society of Civil Engineers.
History
Received: Sep 3, 2013
Accepted: Dec 10, 2013
Published online: Jan 22, 2014
Discussion open until: Jun 22, 2014
Published in print: Aug 1, 2014
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