NSM CFRP Prestressing Techniques with Strengthening Potential for Simultaneously Enhancing Load Capacity and Ductility Performance
Publication: Journal of Composites for Construction
Volume 20, Issue 5
Abstract
The ductility performance of reinforced concrete (RC) members strengthened with carbon-fiber-reinforced polymer (CFRP) reinforcement using near-surface-mounted (NSM) technique has a tendency to decrease with the increase of the prestress level applied to the CFRPs. Hence, in this study, first to assure a sufficient degree of ductility for these prestressed members, a methodology was proposed to determine the maximum prestress level that can be applied to the NSM CFRP reinforcement. Using this methodology, a simplified analytical formulation was developed to determine this maximum allowable prestress level. In the second part, after demonstrating the good predictive performance of a developed three-dimensional finite-element model, first the effect of partial unbonding of prestressed NSM CFRP reinforcement at midspan to increase the ductility performance of strengthened slabs was numerically assessed. Then, a new hybrid-partially bonded system, combining the fully bonded non-prestressed and partially bonded prestressed CFRP reinforcements in the same application according to the NSM technique, was proposed for the flexural strengthening of RC slabs. This hybrid-partially bonded system was capable of providing a better balance in terms of load-carrying and ultimate deflection capacity of prestressed strengthened slabs. At the end, a comparison between the potentialities of fully bonded, partially bonded, and hybrid-partially bonded systems for the flexural strengthening of RC structures is made, and the relevant results are presented and discussed.
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Acknowledgments
The study reported in this paper is part of the project CutInov :Innovative carbon fibre reinforced polymer laminates with capacity for a simultaneous flexural and shear/punching strengthening of reinforced concrete elements, QREN, number 38780, co-financed by the European Regional Development Fund (FEDER) through the Operational Program COMPETE. The first author acknowledge the grant provided by this project.
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Journal of Composites for Construction
Volume 20 • Issue 5 • October 2016
Copyright
© 2016 American Society of Civil Engineers.
History
Received: Aug 1, 2015
Accepted: Dec 10, 2015
Published online: Mar 10, 2016
Discussion open until: Aug 10, 2016
Published in print: Oct 1, 2016
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