Slenderness Limit for Hybrid FRP-Concrete Columns
Publication: Journal of Composites for Construction
Volume 5, Issue 1
Abstract
Due to confinement effects, concrete-filled fiber-reinforced polymer (FRP) tubes have an enhanced performance comparable to conventionally reinforced concrete members. However, the strength and ductility enhancements may result in slender sections, which may be susceptible to instability or geometric and loading imperfections. Because stiffness of FRP is less than that of steel, designers cannot directly use current specifications to size compression members. Uniaxial compression tests on a total of seven hybrid columns, with slenderness ratios up to 36, showed that strength is reduced by as much as 71% of the equivalent short column, and the axial and hoop strains are reduced by as much as 85 and 87%, respectively. These significant reductions result in underutilization of confinement in slender columns. An analytical tool with an incremental approach was developed and compared favorably with test results. A parametric study was carried out, which showed the modulus of elasticity of the tube to have a pronounced effect on the slenderness limit of the column. A new equation was proposed for the slenderness limit of hybrid columns based on a maximum of 5% strength reduction.
Get full access to this article
View all available purchase options and get full access to this article.
References
1.
Amer, A., Arockiasamy, M., and Shahawy, M. ( 1996). “Ultimate strength of eccentricity loaded concrete columns reinforced with CFRP bars.” Proc., Conf. on Advanced Compos. Mat. in Bridges and Struct., M. El Badry, ed., 209–216.
2.
American Concrete Institute (ACI). ( 1995). “Building code requirements for structural concrete and commentary.” ACI 318-95, Detroit.
3.
Daniali, S., and Paramanantham, N. S. ( 1994). “Concrete columns reinforced with fiber reinforced plastic rebars.” Proc., 3rd Mat. Engrg. Conf., Infrastructure: New Mat. and Methods of Repair, ASCE, New York, 567–574.
4.
Kanatharana, J., and Lu, L. ( 1999). “Intermediate length concrete columns reinforced by fiber-reinforced polymer tubes.” Proc., 5th ASCE Mat. Engrg. Congr., L. C. Bank, ed., ASCE, Reston, Va., 535–539.
5.
Kawaguchi, N. ( 1993). “Ultimate strength and deformation characteristics of concrete members reinforced with AFRP rods under combined axial tension or compression and bending.” SP-138, American Concrete Institute, Detroit, 671–683.
6.
Kobayashi, K., and Fujisaki, T. ( 1995). “Compressive behavior of FRP reinforcement in non-prestressed concrete members.” Proc., 2nd Int. RILEM Symp., RILEM, Cachan Cedex, France, 267–274.
7.
MacGregor, J. G., Breen, J. E., and Pfrang, E. O. ( 1970). “Design of slender columns.” ACI J., 67(1), 6–28.
8.
Mirmiran, A. ( 1998). “Length effects on FRP-reinforced concrete columns.” Proc., 2nd Int. Conf. on Compos. in Infrastructure, H. Saadatmanesh and M. Ehsani, eds., University of Arizona, Tucson, Ariz., 518–532.
9.
Mirmiran, A., and Shahawy, M. ( 1996). “A new concrete-filled hollow FRP composite column.” Compos. Part B: Engrg., 27B(3–4), 263–268.
10.
Mirmiran, A., and Shahawy, M. (1997). “Behavior of concrete columns confined by fiber composites.”J. Struct. Engrg., ASCE, 123(5), 583–590.
11.
Mirmiran, A., Shahawy, M., El Khoury, C., and Naguib, W. ( 2000). “Large beam-column tests on concrete-filled composite tubes.” ACI Struct. J., 97(2), 268–276.
12.
Mirmiran, A., Shahawy, M., and Samaan, M. (1999). “Strength and ductility of hybrid FRP-concrete beam columns.”J. Struct. Engrg., ASCE, 125(10), 1085–1093.
13.
Mirmiran, A., Shahawy, M., Samaan, M., El Echary, H., Mastrapa, J. C., and Pico, O. (1998). “Effect of column parameters on FRP-confined concrete.”J. Compos. for Constr., ASCE, 2(4), 175–185.
14.
Samaan, M., Mirmiran, A., and Shahawy, M. (1998). “Model of concrete confined by fiber composites.”J. Struct. Engrg., ASCE, 124(9), 1025–1031.
15.
Structures design guidelines. (1994). Florida Department of Transportation, Tallahassee, Fla.
16.
U.S.-Japan Planning Group (USJPG). ( 1992). “Recommendations for U.S.-Japan cooperative research program—Phase 5: Composite and hybrid structures.” Rep. No. UMCEE 92-29, University of Michigan, Ann Arbor, Mich.
Information & Authors
Information
Published In
Journal of Composites for Construction
Volume 5 • Issue 1 • February 2001
Pages: 26 - 34
History
Received: Jul 9, 1999
Published online: Feb 1, 2001
Published in print: Feb 2001
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.