Ultimate Condition of Fiber Reinforced Polymer-Confined Concrete
Publication: Journal of Composites for Construction
Volume 8, Issue 6
Abstract
One important application of fiber reinforced polymer (FRP) composites is as a confining material for concrete in the retrofit of existing concrete columns by the provision of FRP jackets. Such jackets are commonly formed in a wet layup process, with the fibers being only or predominantly in the hoop direction. It has been well established in recent studies that the rupture strains/strengths of FRP measured in tests on such FRP-confined concrete cylinders fall substantially below those from flat coupon tensile tests, but the causes are unclear. This paper presents the results of a study that is aimed at clarifying these causes. To this end, the paper reports and compares the ultimate tensile strains of two types of FRP (carbon FRP and glass FRP) obtained from three types of tests—flat coupon tensile tests, ring splitting tests, and FRP-confined concrete cylinder tests. Based on comparisons of these test results, it can be concluded that the FRP hoop rupture strains in FRP-confined concrete cylinders are reduced below the ultimate tensile strains from flat coupon tests by at least three factors—(1) the curvature of the FRP jacket; (2) the deformation localization of the cracked concrete; and (3) the existence of an overlapping zone. While the first factor that reduces the in situ strain capacity of FRP on confined concrete is material dependent, the last two factors that result in a nonuniform strain distribution in the jacket are independent of the FRP material properties. The third effect reduces the average hoop rupture but does not affect the distribution of the confining pressure, as the FRP jacket is thicker in the overlapping zone.
Get full access to this article
View all available purchase options and get full access to this article.
References
1.
ASTM. ( 1992). “Standard test method for apparent tensile strength of ring or tubular plastics and reinforced plastics by split disk method.” D 2290-92, West Conshohocken, Pa.
2.
ASTM. ( 1995). “Standard test method for tensile properties of polymer matrix composite materials.” D 3039/D 3039M, West Conshohocken, Pa.
3.
Daniel, I.M., and Ishai, O. ( 1994). Engineering mechanics of composite materials, Oxford University Press, New York.
4.
De Lorenzis, L., and Tepfers, R. (2003). “Comparative study of models on confinement of concrete cylinders with fiber reinforced polymer composites.” J. Compos. Constr., 7(3), 219–237.
5.
Fardis, M. N., and Khalili, H. (1981). “Concrete encased in fiberglass reinforced-plastic.” ACI J., 78(6), 440–446.
6.
Harries, K. A., and Kharel, G. (2002). “Behavior and modeling of concrete subject to variable confining pressure.” ACI Mater. J., 99(2), 180–189.
7.
International Federation for Structural Concrete (FIB). ( 2001). “Externally bonded FRP reinforcement for RC structures.” Technical Rep. on the Design and Use of Externally Bonded Fiber Reinforced Polymer Reinforcement (FRP EBR) for Reinforced Concrete Structures, Lausanne, Switzerland.
8.
Kono, S., Inazuni, M., and Kaku, T. ( 1998). “Evaluation of confining effects of CFRP sheets on reinforced concrete members.” Proc., 2nd Int. Conf. on Composites in Infrastructures ICCI’98, 343–355.
9.
Lam, L., and Teng, J. G. (2003). “Design-oriented stress-strain model for FRP-confined concrete.” Constr. Build. Mater., 17(6-7), 471–489.
10.
Matthys, S., Taerwe, L., and Audenaert, K. ( 1999). “Tests on axially loaded concrete columns confined by fiber reinforced polymer sheet wrapping.” Proc., 4th Int. Symp. on Fiber Reinforced Polymer Reinforcement for Reinforced Concrete Structures, SP-188, C. W. Dolan, S. H. Rizkalla, and A. Nanni, eds., American Concrete Institute, Detroit, 217–229.
11.
Miyauchi, K., Nishbayashi, S., and Inoue, S. ( 1997). “Estimation of strengthening effects with carbon fiber sheet for concrete column.” Proc., 3rd Int. Symp. (FRPRCS-3) on Non-Metallic (FRP) Reinforcement for Concrete Structures, Japan Concrete Institute, Sapporo, Japan, 217–224.
12.
Pessiki, S., Harries, K. A., Kestner, J. T., Sause, R., and Ricles, J. M. (2001). “Axial behavior of reinforced concrete columns confined with FRP jackets.” J. Compos. Constr., 5(4), 237–245.
13.
Saadatmanesh, H., Ehsani, M. R., and Li, M. W. (1994). “Strength and ductility of concrete columns externally reinforced with fiber composite straps.” ACI Struct. J., 91(4), 434–447.
14.
Saafi, M., Toutanji, H. A., and Li, Z. (1999). “Behavior of concrete columns confined with fiber reinforced polymer tubes.” ACI Mater. J., 96(4), 500–509.
15.
Samaan, M., Mirmiran, A., and Shahawy, M. (1998). “Model of concrete confined by fiber composites.” J. Struct. Eng., 124(9), 1025–1031.
16.
Shahawy, M., Mirmiran, A., and Beitelman, A. (2000). “Test and modeling of carbon-wrapped concrete columns.” Composites, Part B, 31, 471–480.
17.
Spoelstra, M. R., and Monti, G. (1999). “FRP-confined concrete model.” J. Compos. Constr., 3(3), 143–150.
18.
Teng, J.G., Chen, J.F., Smith, S.T., and Lam, L. ( 2002). FRP-strengthened RC structures, Wiley, New York.
19.
Toutanji, H. A. (1999). “Stress-strain characteristics of concrete columns externally confined with advanced fiber composite sheets.” ACI Mater. J., 96(3), 397–404.
20.
Watanable, K., et al. ( 1997). “Confinement effect of FRP sheet on strength and ductility of concrete cylinders under uniaxial compression.” Proc. 3rd Int. Symp. (FRPRCS-3) on Non-Metallic (FRP) Reinforcement for Concrete Structures, Vol. 1, Japan Concrete Institute, Sapporo, Japan, 233–240.
21.
Xiao, Y., and Wu, H. (2000). “Compressive behavior of concrete confined by carbon fiber composite jackets.” J. Mater. Civ. Eng., 12(2), 139–146.
22.
Yang, X., Nanni, A., and Chen, G. ( 2001). “Effect of corner radius on the performance of externally bonded FRP reinforcement.” Proc., 5th Int. Conf. on Fibre-Reinforced Plastics for Reinforced Concrete Structures, Thomas Telford, London, 197–204.
Information & Authors
Information
Published In
Journal of Composites for Construction
Volume 8 • Issue 6 • December 2004
Pages: 539 - 548
Copyright
Copyright © 2004 ASCE.
History
Published online: Nov 15, 2004
Published in print: Dec 2004
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.