Behavior of Gravity Load-Designed Rectangular Concrete Columns Confined with Fiber Reinforced Polymer Sheets
Publication: Journal of Composites for Construction
Volume 9, Issue 1
Abstract
This study concentrates on analytical evaluation of the effect of external confinement using fiber reinforced polymers (FRP) sheets on the response of concrete rectangular columns designed for gravity load only and having spliced longitudinal reinforcement at the column base. A general analytical scheme for evaluating the strength capacity and ductility of the columns under combined flexural–axial loads was developed. The analysis takes into account the bond strength degradation of the spliced reinforcement with increase in lateral load by incorporating a generalized bond stress–slip law, and considers the effect of FRP confinement on the stress–strain response of concrete material. Particular emphasis is placed in the analysis on the slip response of the spliced bars and the consequent fixed end rotation that develops at the column base. Results predicted by the analysis showed very good agreement with limited experimental data. A parametric evaluation was carried out to evaluate the effect of different design and strength parameters on the column response under lateral load. Without confinement, the columns suffered premature bond failure and, consequently, low flexural strength capacity. Confining the concrete in the columns end zone at the splice location with FRP sheets enhanced the bond strength capacity of the spliced reinforcement, increased the steel stress that can be mobilized before bond failure occurs, and consequently improved the flexural strength capacity and ductility of the columns. A general design equation, expressed as a function of the main parameters that influence the bond strength capacity between spliced steel bars and FRP confined concrete, is proposed to calculate the area of FRP sheets needed for strengthening of the subject columns.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
This work is supported by the Lebanese National Council for Scientific Research (NCSR). The writers are grateful for that support, and to the Faculty of Engineering and Architecture at the American University of Beirut (AUB) for providing the computer facilities.
References
American Concrete Institute (ACI) Committee 318. (1999). Building code requirements for structural concrete (318-99) and Commentary (318R-99), Farmington Hills, Mich.
American Concrete Institute (ACI) Committee 440. (2002). “Guide for the design and construction of externally bonded FRP systems for strengthening concrete structures.” ACI 440.2R-02, Detroit.
Chaallal, O., and Shahawy, M. (2000). “Performance of fiber-reinforced polymer-wrapped reinforced concrete column under combined axial-flexural loading.” ACI Struct. J., 97(4), 659–668.
Filippou, F. C., Popov, E. P., and Bertero, V. V. (1983). “Effects of bond deterioration on the hysteresis behavior of reinforced concrete joints.” Rep. No. UCB/EERC-83/19, Univ. of California, Berkeley, Calif.
Harajli, M. H. (1988). “Behavior of partially prestressed concrete joints under cyclic loading.” J. Struct. Eng., 114(11), 2525–2543.
Harajli, M., Hamad, B. H., and Karam, K. (2002). “Bond-slip response of reinforcing bars embedded in plain and FRC.” J. Mater. Civ. Eng., 14(16), 503–511.
Harajli, M. H., Hamad, B. H., and Rteil, A. (2004). “Effect of confinement on bond strength between steel bars and concrete.” ACI Struct. J., 101(5), 595–603.
Harajli, M. H., and Mabsout, M. E. (2002). “Evaluation of bond strength of reinforcing bars in plain and fiber reinforced concrete.” ACI Struct. J., 99(4), 509–517.
Harajli, M. H., and Rteil, A. A. (2004). “Effect of confinement using FRP or FRC on seismic performance of gravity load-designed columns.” ACI Struct. J. 101(1), 47–56.
Lam, L., and Teng, J. G. (2002). “Strength models for fiber-reinforced plastic-confined concrete.” J. Struct. Eng., 128(5), 612–623.
Mander, J. B., Priestly, M. J. N., and Park, R. (1988). “Theoretical stress–strain model for confined concrete.” J. Struct. Eng., 114(8), 1804–1826.
Mirmiran, A., and Shahawy, M. (1997). “Behavior of concrete columns confined by fiber composites.” J. Struct. Eng., 123(5), 583–590.
Orangun, C. O., Jirsa, J. O., and Breen, J. E. (1975). “Strength of anchored bars: A reevaluation of test data on development length and splices.” Research Rep. No. 154-3F, Center for Highway Research, Univ. of Texas at Austin, Austin, Tex.
Orangun, C. O., Jirsa, J. O., and Breen, J. E. (1977). “Reevaluation of test data on development length and splices.” ACI J., 74(3), 114–122.
Priestly, M. J. N., Seible, F., and Calvi, M. (1996). Seismic design and retrofit of bridges, Wiley, New York.
Richart, F. E., Brandtzaeg, A., and Brown, R. L. (1928). “A study of the failure of concrete under combined compressive stresses.” Bulletin 185, Univ. of Illinois Engineering Experimental Station, Champaign, Ill.
Saadatmanesh, H., Ehsani, M. R., and Li, M. W. (1994). “Strength and ductility of concrete columns externally confined with fiber composite straps.” ACI Struct. J., 94(1), 434–447.
Scott, B. D., Park, R., and Priestly, M. J. N. (1982). “Stress-strain behavior of concrete confined by overlapping hoops at low and high strain rates.” ACI J., 79(1), 13–27.
Sheikh, S. A., and Uzumeri, S. M. (1980). “Strength and ductility of tied concrete columns.” J. Struct. Div. ASCE, 106(5), 1079–1102.
Sheikh, A. S., and Yau, G. (2002). “Seismic behavior of concrete columns confined with steel and fiber-reinforced polymers.” ACI Struct. J., 99(1), 72–80.
Tan, K. H. (2002). “Strength enhancement of rectangular reinforced concrete columns using fiber-reinforced polymer.” J. Compos. Constr., 6(3), 175–183.
Toutanji, H. A. (1999). “Stress–strain characteristics of concrete column externally confined with advanced fiber composite sheets.” ACI Mater. J., 96(3), 397–404.
Zuo, J., and Darwin, D. (2000). “Splice strength of conventional and high relative rib area bars and high-strength concrete.” ACI Struct. J., 97(4), 630–641.
Information & Authors
Information
Published In
Journal of Composites for Construction
Volume 9 • Issue 1 • February 2005
Pages: 4 - 14
Copyright
© 2005 ASCE.
History
Received: Oct 8, 2003
Accepted: Jan 9, 2004
Published online: Feb 1, 2005
Published in print: Feb 2005
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.