Unified Stress-Strain Model for FRP and Actively Confined Normal-Strength and High-Strength Concrete
Publication: Journal of Composites for Construction
Volume 19, Issue 4
Abstract
Accurate modeling of the complete stress-strain relationship of confined and unconfined concrete is of vital importance in predicting the overall flexural behavior of reinforced concrete structures. The analysis-oriented models, which utilize the dilation characteristics of confined concretes for stress-strain relationship prediction, are well recognized for their versatility in such modeling applications. These models assume that at a given lateral strain, the axial compressive stress and strain of fiber-reinforced polymer (FRP)–confined concrete are the same as those of the same concrete when it is actively confined under a confining pressure equal to that supplied by the FRP jacket. However, this assumption has recently been demonstrated experimentally to be inaccurate for high-strength concrete (HSC). It was shown that at a given axial strain, lateral strains of actively confined and FRP-confined concretes of the same concrete strength correspond when they are subjected to the same lateral confining pressure. However, it was also shown that under the same condition, concrete confined by FRP exhibits a lower strength enhancement compared to that seen in companion actively confined concrete. To develop an accurate model that can describe the experimentally observed behavior, two large test databases were assembled for actively confined and FRP-confined concretes through an extensive review of the literature. Based on the analysis of the databases, a new approach is developed to establish the axial stress difference between the actively confined and FRP-confined concretes. Finally, a unified model is proposed to describe the stress-strain relationships of actively confined and FRP-confined concrete. Comparisons with experimental test results show that the predictions of the proposed model are in good agreement with the test results of both actively confined and FRP-confined concrete, and the model provides improved predictions compared to the existing models.
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References
Aire, C., Gettu, R., Casas, J. R., Marques, S., and Marques, D. (2010). “Concrete laterally confined with fibre-reinforced polymers (FRP): Experimental study and theoretical model.” Materiales De Construccion, 60(297), 19–31.
Albanesi, T., Nuti, C., and Vanzi, I. (2007). “Closed form constitutive relationship for concrete filled FRP tubes under compression.” Constr. Build. Mater., 21(2), 409–427.
Ansari, F., and Li, Q. B. (1998). “High-strength concrete subjected to triaxial compression.” ACI Mater. J., 95(6), 747–755.
Attard, M. M., and Setunge, S. (1996). “Stress-strain relationship of confined and unconfined concrete.” ACI Mater. J., 93(5), 432–442.
Binici, B. (2005). “An analytical model for stress-strain behavior of confined concrete.” Eng. Struct., 27(7), 1040–1051.
Candappa, D. C., Sanjayan, J. G., and Setunge, S. (2001). “Complete triaxial stress-strain curves of high-strength concrete.” J. Mater. Civ. Eng., 209–215.
Carreira, D. J., and Chu, K. H. (1985). “Stress-strain relationship for plain concrete in compression.” J. Am. Concr. Inst., 82(6), 797–804.
Cheek, J., Formichella, N., Graetz, D., and Varasteh, S. (2011). “The behaviour of ultra high strength concrete in FRP confined concrete systems under axial compression.” Honours Bachelor’s thesis, School of Civil, Environmental and Mining Engineering, Univ. of Adelaide, Adelaide, Australia.
Chun, S. S., and Park, H. C. (2002). “Load carrying capacity and ductility of RC columns confined by carbon fiber reinforced polymer.” Proc., 3rd Int. Conf. on Composites in Infrastructure, Univ. of Arizona, Tucson, AZ.
Elwi, A. A., and Murray, D. W. (1979). “A 3D hypoelastic concrete constitutive relationship.” J. Eng. Mech. Div., 105(4), 623–641.
Fam, A. Z., and Rizkalla, S. H. (2001). “Confinement model for axially loaded concrete confined by circular fiber-reinforced polymer tubes.” ACI Struct. J., 98(4), 451–461.
Harries, K. A., and Kharel, G. (2002). “Behavior and modeling of concrete subject to variable confining pressure.” ACI Mater. J., 99(2), 180–189.
Ilki, A., Peker, O., Karamuk, E., Demir, C., and Kumbasar, N. (2008). “FRP retrofit of low and medium strength circular and rectangular reinforced concrete columns.” J. Mater. Civ. Eng., 169–188.
Imran, I., and Pantazopoulou, S. J. (2001). “Plasticity model for concrete under triaxial compression.” J. Eng. Mech., 281–290.
Jiang, T., and Teng, J. G. (2007). “Analysis-oriented stress-strain models for FRP-confined concrete.” Eng. Struct., 29(11), 2968–2986.
Kotsovos, M. D., and Newman, J. B. (1978). “Generalized stress-strain relations for concrete.” J. Eng. Mech. Div., 104(4), 845–856.
Lahlou, K., Aitcin, P. C., and Chaallal, O. (1992). “Behaviour of high-strength concrete under confined stresses.” Cem. Concr. Compos., 14(3), 185–193.
Lam, L., and Teng, J. G. (2004). “Ultimate condition of fiber reinforced polymer-confined concrete.” J. Compos. Constr., 539–548.
Lim, J. C., and Ozbakkaloglu, T. (2014a). “Confinement model for FRP-confined high-strength concrete.” J. Compos. Constr., 04013058.
Lim, J. C., and Ozbakkaloglu, T. (2014b). “Hoop strains in FRP-confined concrete columns: Experimental observations.” Mater. Struct., in press.
Lim, J. C., and Ozbakkaloglu, T. (2014c). “Influence of silica fume on stress-strain behavior of FRP-confined HSC.” Constr. Build. Mater., 63, 11–24.
Lim, J. C., and Ozbakkaloglu, T. (2014d). “Investigation of the influence of application path of confining pressure: Tests on actively confined and FRP-confined concretes.” J. Struct. Eng., 04014203.
Lim, J. C., and Ozbakkaloglu, T. (2014e). “Lateral strain-to-axial strain relationship of confined concrete.” J. Struct. Eng., 04014141.
Lim, J. C., and Ozbakkaloglu, T. (2014f). “Stress-strain model for normal- and light-weight concretes under uniaxial and triaxial compression.” Constr. Build. Mater., 71, 492–509.
Mander, J. B., Priestley, M. J. N., and Park, R. (1988). “Theoretical stress-strain model for confined concrete.” J. Struct. Eng., 1804–1826.
Marques, S. P. C., Marques, D., da Silva, J. L., and Cavalcante, M. A. A. (2004). “Model for analysis of short columns of concrete confined by fiber-reinforced polymer.” J. Compos. Constr., 332–340.
Mills, L. L., and Zimmerman, R. M. (1970). “Compressive strength of plain concrete under multiaxial loading conditions.” ACI J. Proc., 67(10), 802–807.
Mirmiran, A., and Shahawy, M. (1997a). “Behavior of concrete columns confined by fiber composites.” J. Struct. Eng., 583–590.
Mirmiran, A., and Shahawy, M. (1997b). “Dilation characteristics of confined concrete.” Mech. Cohesive-Frictional Mater., 2(3), 237–249.
Moran, D. A., and Pantelides, C. P. (2002a). “Stress-strain model for fiber-reinforced polymer-confined concrete.” J. Compos. Constr., 233–240.
Moran, D. A., and Pantelides, C. P. (2002b). “Variable strain ductility ratio for fiber-reinforced polymer-confined concrete.” J. Compos. Constr., 224–232.
Newman, J. B. (1979). Concrete under complex stress, Dept. of Civil Engineering, Imperial College of Science and Technology, London.
Ozbakkaloglu, T. (2013). “Behavior of square and rectangular ultra high-strength concrete-filled FRP tubes under axial compression.” Compos. Part B, 54, 97–111.
Ozbakkaloglu, T., and Akin, E. (2012). “Behavior of FRP-confined normal- and high-strength concrete under cyclic axial compression.” J. Compos. Constr., 451–463.
Ozbakkaloglu, T., and Lim, J. C. (2013). “Axial compressive behavior of FRP-confined concrete: Experimental test database and a new design-oriented model.” Compos. Part B, 55, 607–634.
Ozbakkaloglu, T., Lim, J. C., and Vincent, T. (2013). “FRP-confined concrete in circular sections: Review and assessment of stress–strain models.” Eng. Struct., 49, 1068–1088.
Ozbakkaloglu, T., and Vincent, T. (2014). “Axial compressive behavior of circular high-strength concrete-filled FRP tubes.” J. Compos. Constr., 04013037.
Pantazopoulou, S. J., and Mills, R. H. (1995). “Microstructural aspects mechanical response of plain concrete.” ACI Mater. J., 92(6), 605–616.
Popovics, S. (1973). “A numerical approach to the complete stress-strain curves for concrete.” Cem. Concr. Res., 3(5), 583–599.
Razvi, S., and Saatcioglu, M. (1999). “Confinement model for high-strength concrete.” J. Struct. Eng., 281–289.
Richard, R. M., and Abbott, B. J. (1975). “Versatile elastic-plastic stress-strain formula.” J. Eng. Mech. Div., 101(4), 511–515.
Richart, F. E., Brandtzaeg, A., and Brown, R. L. (1929). “The failure of plain and spirally reinforced concrete in compression.”, Engineering Experiment Station, Univ. of Illinois, Urbana, IL.
Rousakis, T. C., and Karabinis, A. I. (2012). “Adequately FRP confined reinforced concrete columns under axial compressive monotonic or cyclic loading.” Mater. Struct., 45(7), 957–975.
Samani, A. K., and Attard, M. M. (2012). “A stress-strain model for uniaxial and confined concrete under compression.” Eng. Struct., 41, 335–349.
Sfer, D., Carol, I., Gettu, R., and Etse, G. (2002). “Study of the behavior of concrete under triaxial compression.” J. Eng. Mech., 156–163.
Smith, S. S., Willam, K. J., Gerstle, K. H., and Sture, S. (1989). “Concrete over the top, or: Is there life after peak?” ACI Mater. J., 86(5), 491–497.
Smith, S. T., Kim, S. J., and Zhang, H. (2010). “Behavior and effectiveness of FRP wrap in the confinement of large concrete cylinders.” J. Compos. Constr., 573–582.
Spoelstra, M. R., and Monti, G. (1999). “FRP-confined concrete model.” J. Compos. Constr., 143–150.
Teng, J. G., Huang, Y. L., Lam, L., and Ye, L. P. (2007). “Theoretical model for fiber-reinforced polymer-confined concrete.” J. Compos. Constr., 201–210.
Vincent, T., and Ozbakkaloglu, T. (2013a). “Influence of concrete strength and confinement method on axial compressive behavior of FRP-confined high- and ultra high-strength concrete.” Compos. Part B, 50, 413–428.
Vincent, T., and Ozbakkaloglu, T. (2013b). “Influence of fiber orientation and specimen end condition on axial compressive behavior of FRP-confined concrete.” Constr. Build. Mater., 47, 814–826.
Wu, Y.-F., and Jiang, J.-F. (2013). “Effective strain of FRP for confined circular concrete columns.” Compos. Struct., 95, 479–491.
Xiao, Q. G., Teng, J. G., and Yu, T. (2010). “Behavior and modeling of confined high-strength concrete.” J. Compos. Constr., 249–259.
Xie, J., Elwi, A. E., and Macgregor, J. G. (1995). “Mechanical-properties of high-strength concretes containing silica fume.” ACI Mater. J., 92(2), 135–145.
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Published In
Journal of Composites for Construction
Volume 19 • Issue 4 • August 2015
Copyright
© 2014 American Society of Civil Engineers.
History
Received: Jun 30, 2014
Accepted: Sep 18, 2014
Published online: Oct 16, 2014
Discussion open until: Mar 16, 2015
Published in print: Aug 1, 2015
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