Strengthening Slender Reinforced Concrete Columns Using High-Modulus Bonded Longitudinal Reinforcement for Buckling Control
Publication: Journal of Structural Engineering
Volume 141, Issue 4
Abstract
This paper introduces a model for strengthening slender reinforced concrete columns. The proposed technique aims at controlling second-order lateral deflections using longitudinal high-modulus bonded reinforcement, thereby altering the loading path to intercept the axial load-bending moment (P-M) interaction curve at a higher axial capacity. With the availability of high and ultra-high-modulus carbon fiber–reinforced polymer (CFRP) plates, this approach should be quite efficient according to Euler’s buckling rule, in which column strength is stiffness-controlled. This approach is different from the classical transverse-wrapping method for confinement, a technique that achieves strengthening by enlarging the (P-M) diagram in the compression-controlled region. The proposed model accounts for concrete nonlinearity in compression, cracking in tension, steel rebar plasticity, and certainly geometric nonlinearity, in addition to the possibility of premature CFRP-debonding failure in tension and the lower CFRP strength in compression than tension. The model is validated against experimental results and used in a parametric study to assess the effects of slenderness ratio , axial load initial eccentricity ratio , CFRP reinforcement ratio , and modulus . It was shown that significant gains in axial strength, ranging from 17 to 90%, occur as the magnitudes of , , and increase.
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Acknowledgments
The authors wish to acknowledge the financial support provided by the Ministry of Economic Development and Innovation of Ontario and Queen’s University, through the Postdoctoral Fellowship provided to the first author and the Early Researcher Award and the Chancellor’s Research Award provided to the second author.
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© 2014 American Society of Civil Engineers.
History
Received: Sep 30, 2013
Accepted: Feb 25, 2014
Published online: Jul 14, 2014
Discussion open until: Dec 14, 2014
Published in print: Apr 1, 2015
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