Abstract
One control and three strengthened Reinforced Concrete (RC) beams with box-section were subjected to pure torsion. The proposed strengthening schemes were U-jacketing or U-jacketing with longitudinal strips of fiber-reinforced polymer (CFRP). The U-jacketing strips exhibited a reasonable improvement to the ultimate torque from the experimental investigation. The CFRP strengthening schemes, failure modes, cracking angles, and strain in fibers were investigated and recorded. Besides, three models used for computing the torque of RC members and two for FRP torsional contribution were carefully reviewed and discussed. Based on these models, six combinations were formed by the two-part models addition for predicting the torsional capacity of the strengthened members. The database of 25 strengthened beams was collected from the literature for evaluating prediction of the ultimate torque of the specimens by these six combinational models. In comparison with the laboratorial numbers of the ultimate torque of specimens, the combination of Comb 2 (ACI and fib Bulletin 14 models) and Comb 6 (Chinese and Ghobarah models) presented rational prediction in the ultimate torque of retrofitted beams. However, Comb 6 is a more suitable combination for calculating the ultimate torsional capacity of strengthened beams with rectangular or box-section by FRP entirely wrapping or Uwrap.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
ACI 318 (2011). Building code requirements for structural concrete, American Concrete Institute, Farmington Hills, MI.
Al-Mahaidi, R. and Hii, A. K. (2007). “Bond behaviour of CFRP reinforcement for torsional strengthening of solid and box-section RC beams.” Composites Part B: Engineering, Vol. 38, No. 5, pp. 720–731, DOI: 10.1016/j.compositesb.2006.06.018.
Ameli, M. and Ronagh, H. R. (2007). “Analytical method for evaluating ultimate torque of FRP strengthened reinforced concrete beams.” Journal of Composites for Construction, Vol. 11, No. 4, pp. 384–390, DOI: 10.1061/(ASCE)1090-0268(2007)11:4(384).
Ameli, M., Ronagh, H. R., and Dux, P. F. (2007). “Behavior of FRP strengthened reinforced concrete beams under torsion.” Journal of Composites for Construction, Vol. 11, No. 2, pp. 192–200, DOI: 10.1061/(ASCE)1090-0268(2007)11:2(192).
Ameli, M., Ronagh, H., Bradford, M., and Uy, B. (2005). “Numerical predictions for the ultimate torque capacity of FRP strengthened reinforced concrete beams.” FRP Composites in Civil Engineering-CICE 200. AA Balkema, pp. 579–585.
AS3600 (2009). “Concrete Strucutres.” Australian Standard.
BS 8110 (1985). “Structural use of Concrete Part 2, Code of practice for special circumstances.” British Standards Institution.
Chalioris, C. E. (2007). “Analytical model for the torsional behaviour of reinforced concrete beams retrofitted with FRP materials.” Engineering Structures, Vol. 29, No. 12, pp. 3263–3276, DOI: 10.1016/j.engstruct.2007.09.009.
Chalioris, C. E. (2007). “Behavioural model of FRP strengthened reinforced concrete beams under torsion.” Asia-Pacific Conference on FRP in Structures. Hongkong, China, pp. 111–116.
Chalioris, C. E. (2008). “Torsional strengthening of rectangular and flanged beams using carbon fibre-reinforced-polymers–Experimental study.” Construction and Building Materials, Vol. 22, No. 1, pp. 21–29, DOI: 10.1016/j.conbuildmat.2006.09.003.
China Structural Code (2010). “Code for design of concrete structures GB 50010–2010.” China Structural Science Academe. Beijing.
Deifalla, A. and Ghobarah, A. (2010a). “Full torsional behavior of RC beams wrapped with FRP: Analytical model.” Journal of Composites for Construction, Vol. 14, No. 3, pp. 289–300, DOI: 10.1061/(ASCE) CC.1943-5614.0000085.
Deifalla, A. and Ghobarah, A. (2010b). “Strengthening RC T-beams subjected to combined torsion and shear using FRP fabrics: Experimental study.” Journal of Composites for Construction, Vol. 14, No. 3, pp. 301–311, DOI: 10.1061/(ASCE)CC.1943-5614.0000091.
Dong, J., Wang, Q., and Guan, Z. (2013). “Structural behaviour of RC beams with external flexural and flexural–shear strengthening by FRP sheets.” Composites Part B: Engineering, Vol. 44, No. 1, pp. 604–612, DOI: 10.1016/j.compositesb.2012.02.018.
Fib (2001). Externally bonded FRP reinforcement for RC structures. Lausanne.
Ghobarah, A., Ghorbel, M., and Chidiac, S. (2002). “Upgrading torsional resistance of reinforced concrete beams using fiber-reinforced polymer.” Journal of composites for construction, Vol. 6, No. 4, pp. 257–263, DOI: 10.1061/(ASCE)1090-0268(2002)6:4(257).
Gosbell, T. and Meggs, R. (2002). “West Gate bridge approach spans FRP strengthening Melbourne.” IABSE Symposium Report, International Association for Bridge and Structural Engineering, Australia, pp. 55–60.
Hii, A. K. and Al-Mahaidi, R. (2006). “Experimental investigation on torsional behavior of solid and box-section RC beams strengthened with CFRP using photogrammetry.” Journal of Composites for Construction, Vol. 10, No. 4, pp. 321–329, DOI: 10.1061/(ASCE) 1090-0268(2006)10:4(321).
Hii, A. K. and Al-Mahaidi, R. (2007). “Torsional capacity of CFRP strengthened reinforced concrete beams.” Journal of Composites for Construction, Vol. 11, No. 1, pp. 71–80, DOI: 10.1061/(ASCE)1090-0268(2007)11:1(71).
Hsu, T. T. C. (1984). Torsion of reinforced concrete, Van Nostrand Reinhold, Inc., New York.
Jing, M. and J. Grünberg. (2006). “Mechanical analysis of reinforced concrete box beam strengthened with carbon fiber sheets under combined actions.” Composite Structures, Vol. 73, No. 4, pp. 488–494, DOI: 10.1016/j.compstruct.2005.02.020.
Kachlakev, D. and Mccurry, D. (2000). “Behavior of full-scale reinforced concrete beams retrofitted for shear and flexural with FRP laminates.” Composites Part B: Engineering, Vol. 31, No. 6, pp. 445–452, DOI: 10.1016/S1359-8368(00)00023-8.
Rahal, K. N. (2000). “Torsional strength of reinforced concrete beams.” Canadian Journal of Civil Engineering, Vol. 27, No. 3, pp. 445–453, DOI: 10.1139/l99-083.
Triantafillou, T. C. and Antonopoulos, C. P. (2000). “Design of concrete flexural members strengthened in shear with FRP.” Journal of Composites for Construction, Vol. 4, No. 4, pp. 198–205, DOI: 10.1061/(ASCE)1090-0268(2000)4:4(198).
Zhang, J., Lu, Z., and Zhu, H. (2001). “Experimental study on the behaviour of RC torsional members externally bonded with CFRP.” Proceedings of the International Conference on FRP composites in Civil Engineering. Hongkong, China, pp. 713–722.
Zojaji, A. and Kabir, M. (2012). “Analytical approach for predicting full torsional behavior of reinforced concrete beams strengthened with FRP materials.” Scientia Iranica, Vol. 19, No. 1, pp. 51–63, DOI: 10.1016/j.scient.2011.12.004.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Ma, S., Bunnori, N.M. & Choong, K.K. Prediction of Ultimate Torque of Reinforced Concrete Box Beam Bonded with CFRP Strips. KSCE J Civ Eng 22, 4353–4363 (2018). https://doi.org/10.1007/s12205-018-0872-2
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s12205-018-0872-2