Torsional Strength of RC Beams Considering Tension Stiffening Effect
Publication: Journal of Structural Engineering
Volume 136, Issue 11
Abstract
Stress-strain relationship for a steel bar embedded in concrete differs somewhat to that of a bare steel bar because the surrounding concrete is bonded to the bar. This behavior is known as tension stiffening. This paper presents the results of an analytical and experimental study on the performance of reinforced concrete beams subjected to pure torsion. In particular, the effect of the tension stiffening was discussed and included in the analytical study. Nine RC beams having different torsional reinforcements were tested. Although the torsional strength of RC beams according to the existing design codes (ACI 318-05, EC2, and JSCE-02) depends on neither the average yield stress of steel bars nor the tension stiffening effect, the test results indicated that the steel stress of the beams at peak load increased as the total percentage of reinforcement decreased due to the tension stiffening effect. A new equation including tension stiffening effect was proposed to predict the torsional moment capacities of RC beams. Comparisons between tested and calculated torsional moments of the seventy-one beams showed reasonable agreement.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
The writers would like to thank Prof. K. N. Rahal for providing the material properties and test results of 66 RC beams. This work was supported by Mid-Career Researcher Program through NRF grant funded by the MEST (2009–0078981) of Korea and Priority Research Centers Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2009–0093825).
References
American Concrete Institute (ACI) Committee. (2005). “Building code requirements for reinforced concrete and commentary.” ACT 318-05/ACI 318R-05, Detroit.
Belarbi, A., and Hsu, T. T. C. (1994). “Constitutive laws of concrete in tension and reinforcing bars stiffened by concrete.” ACI Struct. J., 91(4), 465–474.
European Committee for Standardization. (2002). Eurocode 2: Design of concrete structures, CEN, Brussels.
Fang, I. -K., and Shiau, J. -K. (2004). “Torsional behavior of normal- and high-strength concrete beams.” ACI Struct. J., 101(3), 304–313.
Hsu, T. T. C. (1968). “Torsion of structural concrete-behavior of reinforced concrete rectangular members.” Torsion of structural concrete (SP-18), American Concrete Institute, Detroit, 261–306.
Hsu, T. T. C. (1988). “Softened truss model theory for shear and torsion.” ACI Struct. J., 85(6), 624–635.
Japan Society of Civil Engineering (JSCE). (2002). Standard specifications for concrete structures-2002, Tokyo.
Lee, J. -Y., and Kim, U. -Y. (2008). “Effect of longitudinal tensile reinforcement ratio and shear span-to-depth ratio on minimum shear reinforcement in beams.” ACI Struct. J., 105(2), 134–144.
Maekawa, K., Pimanmas, A., and Okamura, H. (2002). Nonlinear mechanics of reinforced concrete, E & FN Spon, London.
McMullen, A. E., and Rangan, V. (1978). “Pure torsion in rectangular sections-a re-examination.” ACI J., 75(10), 511–519.
Rahal, K. N., and Collins, M. P. (1995). “Analysis of sections subjected to combined shear and torsion—A theoretical model.” ACI Struct. J., 92(4), 459–469.
Rahal, K. N., and Collins, M. P. (1996). “Simple model for predicting torsional strength of reinforced and prestressed concrete sections.” ACI Struct. J., 93(6), 658–666.
Shima, H., Chou, L., and Okamura, H. (1987). “Micro and macro models for bond in RC.” J. Coll. Sci., Imp. Univ. Tokyo, 39(2), 133–194.
University of Toronto. (2000). Response 2000, ⟨http://www.civ.utoronto.ca/sect/streng/index3.html⟩ (Dec. 10, 2002).
Vecchio, F. J., and Collins, M. P. (1986). “The modified compression-field theory for reinforced concrete elements subjected to shear.” ACI Struct. J., 83(2), 219–231.
Information & Authors
Information
Published In
Journal of Structural Engineering
Volume 136 • Issue 11 • November 2010
Pages: 1367 - 1378
Copyright
© 2010 ASCE.
History
Received: Dec 26, 2007
Accepted: Apr 5, 2010
Published online: Apr 12, 2010
Published in print: Nov 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.