Numerical Investigation for Moment-Curvature Relationship of CFRP Jacketed RC Columns

Abstract

External jacketing of columns with Carbon Fiber Reinforced Polymer (CFRP) sheets is one of the most commonly used techniques to strengthen the existing reinforced concrete (RC) columns subjected to earthquake loads. In this paper, a parametric study is performed to examine the effects of CFRP jacketing, axial load levels and concrete quality on the total response of the CFRP jacketed RC columns. The newly computer code was developed to determine moment-curvature relationships of CFRP jacketed RC columns. Moment curvature analysis is carried out using three column sections with a fixed reinforcement ratio and three different concrete qualities, and also three different thicknesses of the CFRP wraps. The performance of jacketed RC columns in terms of ductility, strength, stiffness and energy dissipation is investigated. The results of the parametric study showed that strengthening RC columns with CFRP wraps has a significant effect on the total response of jacketed columns due to the confinement of concrete. However, the degree of enhancement in total response is also related to axial load levels.

Keywords

• Moment curvature,carbon fiber reinforced polymer,rectangular RC column,fiber model,GNU Octave

References

1. E. Celebi, M. Aktas, N. Caglar, A. Ozocak, M. Kutanis, N. Mert and Z. Ozcan, “October 23, 2011 Turkey/Van-Ercis earthquake: structural damages in the residential buildings”, Natural Hazards, vol. 65, no. 3, pp. 2287-2310, 2013.
2. P. Juntanalikit, T. Jirawattanasomkul, and A. Pimanmas, “Experimental and numerical study of strengthening non-ductile RC columns with and without lap splice by Carbon Fiber Reinforced Polymer (CFRP) jacketing”, Engineering Structures, vol. 125, pp. 400–418, 2016.
3. A. Hosseini, A. R. Khaloo, and S. Fadaee, “Seismic performance of high-strength concrete square columns confined with carbon fiber reinforced polymers (CFRPs)”, Canadian Journal of Civil Engineering, vol. 32, pp. 569–578, 2005.
4. R. D. Iacobucci, S. A. Sheikh, and O. Bayrak, “Retrofit of Square Concrete Columns with Carbon Fiber-Reinforced Polymer for Seismic Resistance”, ACI Structural Journal, vol. 100, no. 6, pp. 785–794, 2003.
5. P. Faustino, P. Frade and C. Chastre, “Lateral cyclic behaviour of RC columns confined with carbon fibres”, Structures, vol. 5, pp. 196-206, 2016.
6. H. Nakahara and H. Yin, “Self-centering capacity of a structural Frame composed of steel-jacketed concrete columns and steel beams”, Structures, vol. 14, pp. 409-415, 2018.
7. Y. H. Chai, M. J. N. Priestley and F. Seible, “Flexural retrofit of circular reinforced concrete bridge columns by steel jacketing - experimental studies”, Report No. SSRP-91/06, San Diego, University of California, 1991.
8. G. E. Thermou, V. K. Papanikolaou and A. J. Kappos, “Flexural behaviour of reinforced concrete jacketed columns under reversed cyclic loading”, Engineering Structures, vol. 76, pp. 270–282, 2014.

9. M. Soman and J. Mohan, “Rehabilitation of RC columns using ferrocement jacketing”, Construction and Building Materials, vol. 181, pp. 156-162, 2018.
10. A. Kaish, M. R. Alam, M. Jamil, M. F. M. Zain and M. A. Wahed, “Improved ferrocement jacketing for restrengthening of square RC short column”, Construction and Building Materials, vol. 36, pp. 228-237, 2012.
11. M. N. Youssef, M. Q. Feng, and A. S. Mosallam, “Stress-strain model for concrete confined by FRP composites”, Composites: Part B, vol. 38, pp. 614–628, 2007.
12. L. Lam and J. G. Teng, “Stress-strain model for FRP-confined concrete under cyclic axial compression”, Engineering Structures, vol. 31, no. 2, pp. 308–321, 2009.
13. U. Ersoy and G. Ozcebe, Reinforced Concrete, Department of Civil Engineering, Middle East Technical University, METU Press, Ankara, 2008.
14. U. Ersoy and G. Ozcebe, “Moment-curvature relationship of confined concrete sections”, Technical Journal of Turkish Chamber of Civil Engineers, vol. 9, no. DEC., pp. 549–553, 1998.
15. J. W. Eaton, D. Bateman, S. Hauberg, and R. Wehbring, GNU Octave version 4.2.1 manual: a high-level interactive language for numerical computations, http://www.gnu.org/software/octave/doc/interpreter/, 2017.
16. Y. Y. Wei and Y. F. Wu, “Unified stress-strain model of concrete for FRP-confined columns”, Construction and Building Materials, vol. 26, no. 1, pp. 381–392, 2012.
17. J. B. Mander, M. J. N. Priestley, and R. Park, “Theoretical Stress‐Strain Model for Confined Concrete”, Journal of Structural Engineering, vol. 114, no. 8, pp. 1804–1826, Sep. 1988.