This article presents the results of an experimental and analytical study on the behavior of concrete cylinders externally wrapped with fiber-reinforced polymer (FRP) composites and internally reinforced with steel spirals. The experimental work was carried out by testing twenty-four 150 × 300 mm 2 concrete cylinders subjected to pure compression with various confinement ratios and types of confining material. The test results show that the compressive response of concrete confined with both FRP and steel spirals cannot be predicted by summing the individual confinement effects obtained from FRP and steel spirals. This is largely attributable to differences in the inherent material properties of FRP and steel. A new empirical model to predict the axial stress-strain behavior of concrete confined with FRP and steel spirals is proposed. Comparisons between experimental results and theoretic predictions show agreement.
Nishizaki, I., Takeda, N., Ishizuka, Y. and Shimomura, T. ( 2006). A Case Study of Life Cycle Cost Based on a Real FRP Bridge , In: Proceedings of the Third International Conference on FRP Composites in Civil Engineering (CICE2006), Miami , Florida, USA, pp. 99-102.
2.
Ahmad, S.M. and Shah, S.P. ( 1982). Stress-Strain Curves of Concrete Confined by Spiral Reinforcement , ACI Structural Journal, 79(6): 484-490.
3.
Mander, J.B. , Priestley, M.J.N. and Park, R. ( 1988). Observed Stress Strain Behavior of Confined Concrete , ASCE Journal of Structural Engineering, 114(8): 1827-1849.
Fardis, M.N. and Khalili, H. ( 1981). Concrete Encased in Fiberglass-Reinforced Plastic, Journal of American Concrete Institution Proceedings, 78(6): 440-446.
6.
Fardis, M.N. and Khalili, H. ( 1982). FRP-Encased Concrete as a Structural Material, Magazine Concrete Research, 34(121): 191-202.
7.
Ahmad, S.M., Khaloo, A.R. and Irshaid, A. ( 1991). Behavior of Concrete Spirally Confined by Fiberglass Filaments, Magazine Concrete Research, 43(156): 143-148.
8.
Nanni, A. and Bradford, N.M. ( 1995). FRP Jacketed Concrete Under Uniaxial Compression , Construction Building Material, 9(2): 115-124.
9.
Harmon, T.G. and Slattery, K.T. ( 1992). Advanced Composite Confinement of Concrete, In: 1st International Conference on Advanced Composite Materials in Bridges and Structures, Sherbrooke, Quebec, Canada, pp. 299-306.
10.
Picher, F., Rochette, P. and Labossiere, P. ( 1996). Confinement of Concrete Cylinders with CFRP, In: Proceedings of the ICCI’96, Tuscon, Arizona, pp. 829-841.
11.
Watanabe, K. , Nakamura, H., Honda, Y., Toyoshima, M., Isao, M., Fujimaki, T., Kaneto, M. and Shirai, N. ( 1997). Confinement Effect of FRP Sheet on Strength and Ductility of Concrete Cylinders Under Uniaxial Compression, In: Proceedings of the FRPRCS-3, Sapporo, Japan, Vol. 1, pp. 233-240.
12.
Miyauchi, K. , Nishibayashi, S. and Inoue, S. ( 1997). Estimation of Strengthening Effects with Carbon Fiber Sheet for Concrete Column, In: Proceedings of the FRPRCS-3, Sapporo, Japan, Vol. 1, pp. 217-224.
13.
Kono, S., Inazumi, M. and Kaku, T. ( 1998). Evaluation of Confining Effects of CFRP Sheets on Reinforced Concrete Members, In: Proceedings of the ICCI’98 , Tuscon, Arizona, pp. 343-355.
14.
Toutanji, H. (1999). Stress-Strain Characteristics of Concrete Columns Externally Confined with Advanced Fiber Composites Sheets , ACI Materials Journal, 96(3): 397-404.
15.
Matthys, S. , Taerwe, L. and Audenaert, K. ( 1999). Tests on Axially Loaded Concrete Columns Confined by Fiber Reinforced Polymer Sheet Wrapping, In: Proceedings of the FRPRCS-4, Baltimore , pp. 217-228.
16.
Shahawy, M. , Mirmiran, A. and Beitelmann, T. (2000). Tests and Modeling of Carbon Wrapped Concrete Columns, Composites Part B, 31(6-7): 471-480.
17.
Rochette, P. and Labossiere, P. (2000). Axial Testing of Rectangular Column Models Confined with Composites, Journal of Composites for Construction, ASCE, 4(3): 129-136.
18.
Micelli, F. , Myers, J.J. and Murthy, S. ( 2001). Effect of Environmental Cycles on Concrete Cylinders Confined with FRP, In: Proceedings of the CCC2001 International Conference on Composites in Construction , Porto, Portugal.
19.
Rousakis, T. ( 2001). Experimental Investigation of Concrete Cylinders Confined by Carbon FRP Sheets, Under Monotonic and Cyclic Axial Compressive Load. Research Report, Chalmers University of Technology, Goteborg, Sweden.
20.
Mirmiran, A. and Shahawy, M. (1997). Behavior of Concrete Columns Confined by Fiber Composites, ASCE Journal of Structural Engineering, 123(5): 583-590.
21.
Saafi, M., Toutanji, H.A. and Li, Z. ( 1999). Behavior of Concrete Columns Confined with Fiber Reinforced Polymer Tubes, ACI Materials Journal, 96(4): 500-509.
22.
La Tegola, A. and Manni, O. ( 1999). Experimental Investigation on Concrete Confined by Fiber Reinforced Polymer and Comparison with Theoretical Model, In: Proceedings of the FRPRCS-4, Baltimore .
Saadatmanesh, H., Ehsani, M.R. and Li , M.W. (1994). Strength and Ductility of Concrete Columns Externally Reinforced with Fiber Composite Straps, ACI Structural Journal, 91(4): 434-447.
25.
Mirmiran, A. and Shahawy, M. ( 1996). A New Concrete-filled Hollow FRP Composite Column, Composites Part B, 27(3-4): 263-268.
26.
Samaan, M., Mirmiran, A. and Shahawy, M. ( 1998). Model of Concrete Confined by Fiber Composites , ASCE Journal of Structural Engineering, 124(9): 1025-1031.
27.
Spoelstr, M.R. and Monti, G. (1999). FRP-confined Concrete Model, Journal of Composites for Construction, ASCE , 3(3): 143-150.
28.
Teng, J.G. and Lam, L. ( 2004). Behavior and Modelling of FRP-confined Concrete , ASCE Journal of Structural Engineering, 130(11): 1713-1723.
29.
Lee, J.-Y. , Yi, C.-K. and Oh , Y.-J. (2008). Strengthening of Concrete with Mixed Confinement Materials - Steel Hoops and FRP Composites, Science and Engineering of Composites, 15(1): 1-19.
30.
Liu, H.-K. , Tai, N.-H. and Chen, C.-C. (2000). Compression Strength of Concrete Columns Reinforced by Non-adhesive Filament Wound Hybrid Composites , Composites: Part A, 31(3): 221-233.
31.
Lam, L. and Teng, J.G. (2004). Ultimate Condition of FRP-confined Concrete, Journal of Composites for Construction , ASCE, 8(6): 539-548.
32.
Mander, J.B. , Priestley, M.J.N. and Park, R. (1988). Theoretical Stress-Strain Model for Confined Concrete, ASCE Journal of Structural Engineering , 114(8): 1804-1826.
33.
Samman, M., Mirmiran, A. and Shahawy, M. ( 1998). Model of Concrete by Fiber Composites, ASCE Journal of Structural Engineering, 124(9): 1025-1031.
34.
Lam, L. and Teng, J.G. (2003). Design-oriented Stress-Strain Model for FRP-Confined Concrete, Construction and Building Materials, 17: 471-489.
35.
Popovics, S. (1973). A Numerical Approach to the Complete Stress-Strain Curve of Concrete, Cement and Concrete Research, 3(5): 583-599.
36.
Elwi, A.A. and Murray, D.W. ( 1979). A 3D Hypoelastic Concrete Constitutive Relationship , ASCE Journal of Engineering Mechanics Division, 105(4): 623-641.
37.
Muguruma, H. , Watanabe, F., Iwashizmiu , T. and Mitsueda, R. (1983). Ductility Improvement of High Strength Concrete by Lateral Confinement, Transactions of Japan Concrete Institute, 5: 403-410.
