This paper aims to investigate the mechanical behavior of columns with partial deteriorated strength and to evaluate the availability of the partial confinement. Five steel reinforced concrete columns have been tested. Different layers of CFRP sheets have been wrapped on the deteriorated strength part. Columns are subjected to axial compression until failure. Axial load, and axial and transverse strains are measured to investigate confinement levels supplied by CFRP sheets. Experimental results indicate that both the load capacity and the ductility of the deteriorated strength part could be significantly increased, subsequently; the load capacity of the entire column can be enhanced higher than those of the original columns. An existing analytical model on FRP reinforcement is used to predict the ultimate load and to evaluate the improvement effectiveness of partial confinement. The prediction provided by theoretical model shows good agreement with the experimental results. Findings of this paper show that partial confinement on deteriorated parts of concrete columns would be developed as an alternative to diminish cost and time consumption in practice.
Demers, M. and Neale, K.W. ( 1999). Confinement of Reinforced Concrete Columns with Fiber-Reinforced Composite Sheets - an Experimental Study, Canadian Journal of Civil Engineering, 26(2): 226-241.
2.
Saadatmanesh, H., Ehsani, M.R. and Li, M.W. (1994). Strength and Ductility of Concrete Columns Externally Reinforced With Fiber Composite Straps, Structural Journal, 91: 434-447.
3.
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, Construction and Building Materials, 21(11): 1991-1996.
4.
Labossiere, P. and Rochette, P. (2000). Axial Testing of Rectangular Column Models Confined with Composites, Journal of Composites for Construction, 4(3): 129-36.
5.
Mirmiran, A., Shahawy, M. and Samaan, M. ( 1998). Effect of Column Parameters on FRP-confined Concrete , Journal of Composites for Construction, 2(2): 175-85.
6.
Toutanji, H.A. and Saafi, M. (2002). Stress-Strain Behavior of Concrete Columns Confined with Hybrid Composite Materials, Materials and Structures, 35: 338-347.
7.
Xiao, Y. ( 2004). Applications of FRP Composites in Concrete Columns, Advances in Structural Engineering, 7: 335-343.
8.
Mander, J.B. , Priestley, M.J.N. and Park, R. (1988). Theoretical Stress-Strain Model for Confined Concrete, Journal of Structural Engineering , 114(8): 1804-1826.
9.
Demers, M. and Neale, K.W. ( 1994). Strengthening of Concrete Columns with Unidirectional Composite Sheets, Canadian Society of Civil Engineering, 91: 895-950.
10.
Karbhari, V.M. and Gao, Y. (1997). Composite Jacketed Concrete under Uniaxial Compression Verification of Simple Design Equations, Journal of Material in Civil Engineering, ASCE, 9: 185-93.
11.
Karbhari, V.M. (2001). Materials Considerations in FRP Rehabilitation of Concrete Structures, Journal of Materials in Civil Engineering, 13: 90-97.
12.
Shahawy, M. , Mirmiran, A. and Beitelman, T. (2000). Tests and Modeling of Carbon-Wrapped Concrete Columns, Composites Part B: Engineering , 31: 471-80.
13.
Mirmiran, A. and Shahawy, M. (1997). Behavior of Concrete Columns Confined by Fiber Composites, Journal of Structural Engineering, 123(5): 583-590.
14.
Shahawy, M. and Beitelman, T. (1996). Structural Repair and Strengthening of Damaged Pre-stressed Concrete Bridges Utilizing Externally Bonded Carbon Materials, In: International SAMPE Symposium and Exhibition (Proceedings), 41: 1311-1318.
Xiao, J.Z., Long, H.Y. and Shi, X.F. ( 2004). Study on Seismic Behavior of High-Level Axial Compression Concrete Columns Strengthened with FRP, Tongji Daxue Xuebao/Journal of Tongji University, 32: 990-995.
17.
Lam, L. and Teng, J.G. (2003). Design-Oriented Stress-Strain Model for FRP-confined Concrete in Rectangular Columns, Journal of Reinforced Plastics & Composites, 22: 1149-1186.
18.
Lam, L. and Teng, J.G. ( 2001). A New Stress-Strain Model for FRP-Confined Concrete, In: Proceedings of the International Conference on FRP Composites in Civil Engineering, Hong Kong, China, pp. 283-292.
19.
Lam, L. and Teng, J.G. (2002). Strength Models for Fiber Reinforced Plastic Confined Concrete, Journal of Structure Engineering, 128(5): 612-623.
20.
Ilki, A. and Kumbasar, N. ( 2002). Behavior of Damaged and Undamaged Concrete Strengthened by Carbon Fiber Composite Sheets, Structural Engineering and Mechanics, 13(1): 75-90.
21.
Karabinis, A.I. and Rousakis, T.C. (2002). Concrete Confined by FRP Material: a Plasticity Approach, Engineering Structures , 24: 923-932.
22.
Campione, G. , Miraglia, N. and Papia, M. (2004). Strength and Strain Enhancements of Concrete Columns Confined with FRP Sheets, Structural Engineering and Mechanics, 18: 769-790.
23.
Wang, Y.C. and Hsu, K. ( 2008). Design of FRP-wrapped Reinforced Concrete Columns for Enhancing Axial Load Carrying Capacity, Composite Structures , 82: 132-139.
24.
Omar, C., Hassan, M. and Shahawy, M. ( 2003). Performance of Axially Loaded Short Rectangular Columns Strengthened with Carbon Fiber-Reinforced Polymer Wrapping, Journal of Composites for Construction, 7: 200-208.
25.
Wang, Y.C. and Restrepo, J.I. ( 2001). Investigation of Concentrically Loaded Reinforced Concrete Columns Confined with Glass Fiber-Reinforced Polymer Jackets, ACI Structural Journal, 98: 277-285.
26.
Kumutha, R. , Vaidyanathan, R. and Palanichamy , M.S. (2007). Behaviour of Reinforced Concrete Rectangular Columns Strengthened using GFRP , Cement and Concrete Composite, 29: 609-615.
27.
Salloum, A.I. and Yousef, A. (2007). Influence of Edge Sharpness on the Strength of Square Concrete Columns Confined with FRP Composite Laminates , Composites Part B: Engineering, 12: 640-650.
28.
Wang, L.M. and Wu, Y.F. ( 2008). Effect of Corner Radius on the Performance of CFRP-Confined Square Concrete Columns, Test. Engineering Structures, 30: 498-505.
29.
Wu, Y.F. ( 2004). The Effect of Longitudinal Reinforcement on the Cyclic Shear Behaviour of Glass Fiber Reinforced Gypsum Wall Panels, Tests. Engineering Structures, 26(11): 1633-1646.
