Response of Concrete Corbels Reinforced with Internal Steel Rebars and External Composite Sheets: Experimental Testing and Finite Element Modeling
Publication: Journal of Composites for Construction
Volume 18, Issue 1
Abstract
This paper aims to investigate the structural response of concrete corbels reinforced internally with steel rebars and externally with carbon fiber-reinforced polymer (CFRP) composite sheets. Nine specimens were constructed and tested. Test parameters included the amount of internal longitudinal steel rebars and configuration of the external composite sheets. Nine two-dimensional finite-element (FE) models were developed, assuming a perfect bond between the CFRP and concrete. Three additional FE models were developed in which an interfacial bond stress-slip model was adopted between the diagonal CFRP reinforcement and the concrete. The external CFRP composite reinforcement resulted in up to 40% increase in the load capacity. The contribution of the external CFRP reinforcement to the load capacity decreased with an increased amount of internal steel rebars. The addition of primary longitudinal CFRP sheets in a direction parallel to the primary steel rebars reduced the steel strains and increased the yield and ultimate loads. The inclusion of secondary CFRP longitudinal reinforcement at the midheight of the corbels did not result in additional strength gain. The diagonal CFRP reinforcement restricted growth and widening of the shear cracks, and hence, increased the gain in the load capacity. The numerical load capacity was in the range of 10% error band. The numerical crack pattern, deflection response, and steel and CFRP strain responses were in good agreement with those measured experimentally. The integration of the interfacial bond stress-slip model in the FE analysis between the diagonal CFRP reinforcement and concrete resulted in more conservative/accurate predictions for the structural response.
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Acknowledgments
The authors wish to express their gratitude to the UAEU for funding this project under grant number 21N113. The partial support provided by the Emirates Foundation under grant no. 2009/052 (21N031) is also acknowledged. The help provided by the research assistant Mr. Abdelrahman Al-Sallamin, the lab specialist Eng. Tarek Salah, and the lab technician Mr. Faisel Abdel-Wahab throughout testing is appreciated.
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© 2013 American Society of Civil Engineers.
History
Received: Mar 24, 2013
Accepted: Jun 11, 2013
Published online: Jun 13, 2013
Published in print: Feb 1, 2014
Discussion open until: Mar 1, 2014
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