Effectiveness of CFRP Confinement and Compressive Strength of Square Concrete Columns
Publication: Journal of Composites for Construction
Volume 23, Issue 6
Abstract
Existing strength models for square concrete columns confined with fiber-reinforced polymer (FRP) laminates are almost all proposed on the basis of test data from relatively small-scale specimens. The possibility of extrapolating the models to represent the behavior of real-scale square columns still needs further studies. In particular, the quantitative evaluation of size effect is still a subject that requires systematic research. To address this knowledge gap, this paper reports the results of testing on 42 relatively large-scale square concrete columns () under axial compression. The testing demonstrated that the carbon FRP (CFRP) wrapping strain around the perimeter exhibits a certain regularity, even under very high axial load. The strain efficiency factor at corner from the large-scale columns is lower than those from small specimens, and its value shows an increasing trend as the corner radius ratio increases. Based on the available data, confinement effectiveness provided by FRP wraps was quantified as a comprehensive function considering the influence of lateral confinement level, corner radius ratio, and size effect. A database of FRP-confined square columns was assembled and used to assess the predictability of typical existing models. The results show that the existing models may significantly overestimate the strength of real-size structural columns wrapped by FRP. A modified strength model for FRP-confined square columns is also presented and is shown to have good correlation with experimental results.
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Data Availability Statement
All data and models generated or used during this study are available from the corresponding author by request.
Acknowledgments
The experimental work of this research was conducted at the Ministry of Education Key Laboratory of Building Safety and Efficiency at Hunan University with support from the National Key Basic Research Program of China (973-2012CB026200), the National Natural Science Foundation Key Project (NSFC 51438010), and the Thousand-talent National Expert Scholarships. The study was also partially supported under the Italian DPC-ReLUIS Executive Project 2014-16, Research Line “Innovative Materials.”
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Journal of Composites for Construction
Volume 23 • Issue 6 • December 2019
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©2019 American Society of Civil Engineers.
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Received: Aug 26, 2017
Accepted: Feb 25, 2019
Published online: Aug 20, 2019
Published in print: Dec 1, 2019
Discussion open until: Jan 20, 2020
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