Stress and Strain Behavior of Slender Concrete Columns Retrofitted with CFRP Composites

Abstract

This article presents the results of experimental studies about axial stress—strain behavior of retrofitted slender concrete columns with CFRP composites. In this study, 30 unreinforced concrete cylinders 100 mm diameter with variable height of 200, 400, 600, 800, and 1000 mm were prepared and retrofitted. In each group, a plain specimen (unwrapped) and five wrapped specimens with different fiber orientations (0, 0/0, 90/0, 45, and 45/0) were tested under compressive axial force up to failure. At the end, analytical models were proposed for ultimate strength and ultimate strain of the slender specimens. The results have shown that the CFRP composites are most effective in increasing the strength and ductility of slender columns.

Keywords

concrete column slenderness retrofitting CFRP fiber orientation strength ductility.

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References

Karbhari, V.M. and Gao, Y. (1997). Composite Jacketed Concrete under Uniaxial Compression-Verification of Simple Design Equations, J. Mater. Civil. Engng. ASCE, 9(4): 185-193.

Shahawy, M. , Mirmiran, A. and Beitelman, T. ( 2000). Tests and Modeling of Carbon-wrapped Concrete Columns, Compos. Part B: Engng, 31(6-7): 471-480.

Teng, J.G. and Lam, L. ( 2004). Behavior and Modeling of Fiber Reinforced Polymer-confined Concrete, J. Struct. Engng. ASCE, 130(11): 713-723.

Sadeghian, P. , Rahai, A.R. and Ehsani, M.R. (2008). Numerical Modeling of Concrete Cylinders Confined with CFRP Composites, J. Reinforced Plastic & Compos (in press).

Sadeghian, P. ( 2007). Strength and Ductility Evaluation of Strengthened Rectangular Concrete Columns with CFRP Composites under Axial Loading and Bending Moment , Ph.D. Thesis, Amirkabir University of Technology, Tehran, Iran.

ACI-440 Committee (2002). Guide for the Design and Construction of Externally Bonded FRP Systems for Strengthening Concrete Structures, ACI 440, Detroit.

Intelligent Sensing for Innovative Structures (ISIS) ( 2001). Externally Bonded FRP for Strengthening Reinforced Concrete Structures, The Canadian Network of Centres of Excellence on ISIS, ISIS M04, Winnipeg, Manitoba, Canada.

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. Construct. ASCE, 2(4): 175-185.

Mirmiran, A. , Shahawy, M. and Beitleman, T. (2001). Slenderness Limits for Hybrid FRP-Concrete Columns, J. Compos. Construct. ASCE, 5(1): 26-34.

10.

Silva, M.A.G. and Rudrigues, C.C. (2006). Size and Relative Stiffness Effects on Compressive Failure of Concrete Columns Wrapped with Glass FRP , J. Mater. Civil. Engng. ASCE, 18(3): 334-342.

11.

Pan, J.L. , Xu, T. and Hu , Z.J. (2007). Experimental Investigation of Load Carrying Capacity of the Slender Reinforced Concrete Columns Wrapped with FRP, J. Construct. and Building Mater., 21(11): 1991-1996.