Full Torsional Behavior of RC Beams Wrapped with FRP: Analytical Model
Publication: Journal of Composites for Construction
Volume 14, Issue 3
Abstract
Torsion failure is an undesirable brittle form of failure. Although previous experimental studies have shown that using fiber-reinforced polymer (FRP) sheets for torsion strengthening of reinforced concrete (RC) beams is an effective solution in many situations, very few analytical models are available for predicting the section capacity. None of these models predicted the full behavior of RC beams wrapped with FRP, account for the fact that the FRP is not bonded to all beam faces, or predicted the ultimate FRP strain using equations developed based on testing FRP strengthened beams in torsion. In this paper, an analytical model was developed for the case of the RC beams strengthened in torsion. The model is based on the basics of the modified compression field theory, the hollow tube analogy, and the compatibility at the corner of the cross section. Several modifications were implemented to be able to take into account the effect of various parameters including various strengthening schemes where the FRP is not bonded to all beam faces, FRP contribution, and different failure modes. The model showed good agreement with the experimental results. The model predicted the strength more accurately than a previous model, which will be discussed later. The model predicted the FRP strain and the failure mode.
Get full access to this article
View all available purchase options and get full access to this article.
References
ACI. (1996). “State-of-the art report on fiber reinforced plastic (FRP) reinforcement for concrete structures.” Committee 440 Rep. No. ACI 440R-96, American Concrete Institute, Farmington Hills, Mich.
Ameli, M., and Ronagh, H. R. (2007). “Analytical method for evaluating ultimate torque of FRP strengthened reinforced concrete beams.” J. Compos. Constr., 11(4), 384–390.
Arbesman, B. (1975). “Effect of stirrup cover and amount of reinforcement on shear capacity of reinforced concrete beams.” MEng thesis, Univ. of Toronto.
Belarbi, A., and Hsu, T. T. C. (1995). “Constitutive laws of softened concrete in biaxial tension-compression.” ACI Struct. J., 92(5), 562–573.
Collins, M. P., and Mitchell, D. (1997). Prestressed concrete structures, Response, Canada.
Deifalla, A. F. (2007). “Behaviour and strengthening of RC T-girders in torsion and shear.” Ph.D. thesis, McMaster Univ., Canada.
FIB. (2001). “Externally bonded FRP reinforcement for RC structures.” (CEB-FIP) Technical Rep. 14, Task Group 9.3, International Federation for Structural Concrete, 200.
Ghobarah, A., Ghorbel, M., and Chidiac, S. (2002). “Upgrading torsional resistance of RC beams using FRP.” J. Compos. Constr., 6(4), 257–263.
Hii, A. K. Y., and Al-Mahadi, R. (2007). “Torsional capacity of CFRP strengthened reinforced concrete beams.” J. Compos. Constr., 11(1), 71–80.
Ilki, A. K. N., and Koc, V. (2004). “Low strength concrete members externally confined with FRP sheets.” Structural Engineering and Mechanics, 18(2), 167–194.
Mitchell, D., and Collins, M. P. (1974). “Diagonal compression field theory—A rational model for structural concrete in pure torsion.” ACI Struct. J., 71, 396–408.
Onsongo, W. M. (1978). “Diagonal compression field theory for reinforced concrete beams subjected to combined torsion, flexure, and axial load.” Ph.D. thesis, Univ. of Toronto, Toronto.
Panchacharam, S., and Belarbi, A. (2002). “Torsional behaviour of reinforced concrete beams strengthened with FRP composites.” 1st FIB Congress on Concrete Structures in the 21st Century, Osaka, Japan.
Rahal, K. N., and Collins, M. P. (1995). “Effect of the thickness of concrete cover on the shear-torsion interaction—An experimental investigation.” ACI Struct. J., 92(3), 334–342.
Sause, R., Harries, K. A., Walkup, S. L., Pessiki, S., and Ricles, J. M. (2004). “Flexural behaviour of concrete columns retrofitted with carbon fibre reinforced polymer jackets.” ACI Struct. J., 101(5), 708–716.
Teng, J. G., Chen, J. F., Smith, S. T., and Lam, L. (2002). FRP strengthened RC structures, Wiley, Chichester, U.K.
Vecchio, F. J., and Collins, M. P. (1982). “The response of reinforced concrete to in-plane shear and normal stresses.” Publication No. 82-03, Dept. of Civil Engineering, Univ. of Toronto, Toronto.
Zhang, J. W., Lu, T. Z., and Zhu, H. (2001). Experimental study on the behavior of RC torsional members externally bonded with CFRP: FRP composites in civil engineering, I, Elsevier Science, New York.
Information & Authors
Information
Published In
Journal of Composites for Construction
Volume 14 • Issue 3 • June 2010
Pages: 289 - 300
Copyright
© 2010 ASCE.
History
Received: May 20, 2009
Accepted: Oct 23, 2009
Published online: Feb 3, 2010
Published in print: Jun 2010
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.