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.
Get full access to this article
View all available purchase options and get full access to this article.
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.
References
Abdalla, H., Torkey, A., Haggag, H., and Abu-Amira, A. (2003). “Design against cracking at openings in reinforced concrete beams strengthened with composite sheets.” Compos. Struct., 60(2), 197–204.
Ahmed, A., Fayyadh, M., Naganathan, S., and Nasharuddin, K. (2012). “Reinforced concrete beams with web openings: A state of the art review.” Mater. Des., 40, 90–102.
American Concrete Institute. (2005). “Building code requirements for structural concrete.”, Farmington Hills, MI.
ATENA 2D [Computer software]. Prague, Czech Republic, Cervenka Consulting.
Bousselham, A., and Chaallal, O. (2006). “Effect of transverse steel and shear span on the performance of RC beams strengthened in shear with CFRP.” Compos. Part B, 37(1), 37–46.
British Standards Institution. (2000). “Concrete—Part 1: Specification, performance, production and conformity.” BS EN 206-1:2000, London.
Campione, G. (2009). “Flexural response of FRC corbels.” Cem. Concr. Compos., 31(3), 204–210.
Campione, G., La Mendola, L., and Mangiavillano, M. (2007). “Steel fiber-reinforced concrete corbels: Experimental behavior and shear strength prediction.” ACI Struct. J., 104(5), 570–579.
Campione, G., La Mendola, L., and Papia, M. (2005). “Flexural behaviour of concrete corbels containing steel fibers or wrapped with FRP sheets.” Mater. Struct., 38(280), 617–625.
Carolin, A., and Taljsten, B. (2005). “Experimental study of strengthening for increased shear bearing capacity.” J. Compos. Constr., 488–496.
Chaallal, O., Shahawy, M., and Hassan, M. (2002). “Performance of reinforced concrete T-girders strengthened in shear with CFRP fabrics.” ACI Struct. J., 99(3), 335–343.
Comite Euro-International du Beton. (1990). CEB-FIP model code, Thomas Telford, London.
Cook, W., and Mitchell, D. (1988). “Studies of disturbed regions near discontinuities in reinforcement concrete members.” ACI Struct. J., 85(2), 206–216.
El-Maaddawy, T., and El-Ariss, B. (2012). “Behavior of concrete beams with short shear span and web opening strengthened in shear with CFRP composites.” J. Compos. Constr., 47–59.
El-Maaddawy, T., and Sherif, S. (2009). “FRP composites for shear strengthening of reinforced concrete deep beams with openings.” Compos. Struct., 89(1), 60–69.
El-Maaddawy, T., Soudki, K., and Topper, T. (2005). “Computer-based mathematical model for performance prediction of corroded beams repaired with FRPs.” J. Compos. Constr., 227–235.
Fattuhi, N. I. (1987). “SFRC corbel tests.” ACI Struct. J., 84(2), 119–123.
Fattuhi, N. I. (1994). “Reinforced corbels made with plain and fibrous concretes.” ACI Struct. J., 91(5), 530–536.
Fattuhi, N., and Hughes, B. (1989). “Ductility of reinforced concrete corbels containing either steel fibers or stirrups.” ACI Struct. J., 86(6), 644–651.
Hawileh, R., El-Maaddawy, T., and Naser, M. (2012). “Nonlinear finite element modeling of concrete deep beams with openings strengthened with externally-bonded composites.” Mater. Des., 42, 378–387.
Hong, S., and Ha, T. (2012). “Effective capacity of diagonal strut for shear strength of reinforced concrete beams without shear reinforcement.” ACI Struct. J., 109(2), 139–148.
Islam, M., Mansur, M., and Maalej, M. (2005). “Shear strengthening of RC deep beams using externally bonded FRP systems.” Cem. Concr. Compos., 27(3), 413–420.
Kupfer, H., Hilsdorf, H., and Rüsch, H. (1969). “Behavior of concrete under biaxial stress.” ACI J., 66(8), 656–666.
Lu, X., Ye, L., Teng, J., and Jiang, J. (2005). “Bond–slip models for FRP sheets/plates bonded to concrete.” Eng. Struct., 27(6), 920–937.
Pellegrino, C., and Modena, C. (2006). “Fiber reinforced polymer shear strengthening of reinforced concrete beams: Experimental study and analytical modeling.” ACI Struct. J., 103(5), 720–728.
Vecchio, F., and Collins, M. (1986). “The modified compression-field theory for reinforced concrete elements subjected to shear.” ACI J., 83(2), 219–231.
Zhang, Z., Hsu, C., and Moren, J. (2004). “Shear strengthening of reinforced concrete deep beams using carbon fiber reinforced polymer laminates.” J. Compos. Constr., 403–414.
Information & Authors
Information
Published In
Journal of Composites for Construction
Volume 18 • Issue 1 • February 2014
Copyright
© 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
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.