Strength and Ductility of RC Beams Repaired with Bonded CFRP Laminates
Publication: Journal of Bridge Engineering
Volume 6, Issue 5
Abstract
The objective of this study is to investigate the strength and ductility aspects of reinforced concrete (RC) beams strengthened with an externally bonded carbon fiber reinforced polymer (CFRP) laminate and to examine how such retrofitting affects strength, deflection, curvature, and energy, as exemplified by the area under the load-deflection curve of the strengthened composite beam. Three series of tests on eleven RC beams were carried out and their ultimate load capacities and ductilities evaluated. The variables in the experimental program were longitudinal steel ratio, volume of internal stirrups, and the location and configuration of external anchorages. The results show that both deflection and energy absorption are drastically reduced when beams are strengthened with bonded CFRP plates without external anchorages. Suitably designed and positioned external anchorages allow much of this lost ductility to be regained; however, even then the ductility of the strengthened beam cannot be restored to its original level. It is shown that definitions of ductility based on deflection and energy are able to give a good and rational representation of the physical aspects of ductility of RC beams strengthened with bonded CFRP laminates with or without external anchorages. The results show that the effects on ductility arising from strengthening existing RC beams with CFRP laminates cannot be ignored, even if it is not clear at this stage how to apply the concept of ductility indices and ductility ratios developed in this paper in design practice.
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References
1.
ASCE. ( 1998). “ASCE infrastructure report card: a remarkable success story in raising the profile of civil engineers.” ASCE News, ASCE, 23(9), 24.
2.
Bencardino, F., Spadea, G., and Swamy, R. N. ( 1996). “Use of non-metallic reinforcements for strengthening/rehabilitating new and deteriorating structures.” Proc., 25th AIAS Nat. Conf., Int. Conf. on Mat. Engrg., Editrice Salentina, Gallipoli, Lecce, Italy, 1185–1192.
3.
Bertero, V. V. ( 1977). “Final recommendations—working group 10: seismic testing and performance.” Proc., Workshop on Earthquake Resistant Reinforced Concrete Build. Constr., University of California, Berkeley, Calif., 1, 38–39.
4.
Brown, J. H. ( 1989). “Factors affecting steel corrosion in concrete substructures.” Proc., IABSE Symp., International Association for Bridge and Structural Engineering, Zurich, 2, 450–464.
5.
Gjorv, O. E. ( 1992). “Durability of concrete structures in the ocean environment.” Proc., FIP Symp. on Concrete Sea Struct., London, 141–145.
6.
Hobbs, B., Swamy, R. N., and Roberts, M. ( 1996). “Corrosion performance of steel-plated reinforced concrete beams after long term natural exposure.” ACI Publication SP-165, American Concrete Institute, Detroit, 101–126.
7.
Ingvarsson, H., and Westerberg, B. ( 1986). Operation and maintenance of bridges and other bearing structures, Swedish Transport Research Board, Stockholm, Sweden.
8.
Jones, R., Swamy, R. N., and Charif, A. ( 1988). “Plate separation and anchorage of reinforced concrete beams strengthened by epoxy-bonded steel plates.” The Struct. Engr., 66(5), 85–94.
9.
Mukhopadhyaya, P., Swamy, N., and Lynsdale, C. J. (1998). “Optimizing structural response of beams strengthened with GFRP plates.”J. Compos. for Constr., ASCE, 2(2), 87–95.
10.
National Academy of Sciences. ( 1987). “Concrete durability—a multibillion dollar opportunity.” Publ. No. NMAB-437, National Materials Advisory Board, Washington, D.C.
11.
Rasheeduzzafar, D. F. H., and Al-Gahtani, A. S. ( 1984). “Deterioration of concrete structures in the environment of the Middle East.” J. ACI, 81(1), 13–20.
12.
Rasheeduzzafar, D. F. H., and Al-Ghatani, A. S. ( 1985). “Corrosion of reinforcement in concrete structures in the Middle East.” Concrete Int., 7(9), 48–55.
13.
Ritchie, P. A., Thomas, D. A., Lu, Le-Wu, and Connelly, G. M. ( 1991). “External reinforcement of concrete beams using fiber reinforced plastics.” ACI Struct. J., 88(4), 490–500.
14.
Saadatmanesh, H., and Ehsani, M. R. (1991). “RC beams strengthened with GFRP plates. I: Experimental study.”J. Struct. Engrg., ASCE, 117(11), 3417–3433.
15.
Swamy, R. N. ( 1996). Advanced technology for design and fabrication of composite materials and structures, Kluwer Academic Publishers, Dordrecht, The Netherlands, 15–30.
16.
Swamy, R. N., and Gaul, R., eds. ( 1996). Repair and strengthening of concrete members with adhesive bonded plates, American Concrete Institute, Detroit.
17.
Swamy, R. N., Hobbs, B., and Roberts, M. ( 1995). “Structural behavior of externally bonded steel plated reinforced concrete beams after long term natural exposure.” The Struct. Engr., 73(16), 255–261.
18.
Swamy, R. N., Lynsdale, C. J., and Mukhopadhyaya, P. ( 1996). “Effective strengthening with ductility: use of externally bonded plates of non-metallic composite materials.” Advanced composite materials in bridges and structures, M. El-Badry, ed., Canadian Society for Civil Engineering, Montreal, 481–488.
19.
Swamy, R. N., and Mukhopadhyaya, P. ( 1995). “Role and effectiveness of non-metallic plates in strengthening and upgrading concrete structures.” Proc., Nonmetallic (FRP) Reinforcement for Concrete Struct., L. Taerwe, ed., E & FN Spon, London, 473–482.
20.
Triantafillou, T. C., and Plevris, N. ( 1992). “Strengthening of RC beams with epoxy-bonded fiber-composite materials.” Mat. and Struct., 25, 201–211.
21.
Wallbank, E. J. ( 1989). The performance of concrete bridges, Dept. of Transport, Her Majesty's Stationary Office, London.
Information & Authors
Information
Published In
Journal of Bridge Engineering
Volume 6 • Issue 5 • October 2001
Pages: 349 - 355
History
Received: Oct 22, 1998
Published online: Oct 1, 2001
Published in print: Oct 2001
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