Role of Bond in RC Beams Strengthened with Steel and FRP Plates
Publication: Journal of Structural Engineering
Volume 127, Issue 12
Abstract
This paper discusses the problem of predicting the stiffness, load capacity, and failure modes of RC members strengthened in bending with bonded steel or carbon-fiber–reinforced plastic thin plates. A critical issue of this strengthening technique is that, when the plate debonds, the load capacity suddenly drops and the failure mode is typically brittle. Because of the concrete cracking diffusion and the yielding of the steel rebars, a significant amplification of the bond stresses takes place at the beam-plate interface. Delamination occurs when the bond strength is reached locally. To properly describe and realistically predict the behavior of the strengthened beams, a displacement-based fiber beam model is used. Bond slip between the beam and the plate is included by assuming separate displacement fields in the beam and in the strengthening plate. The proposed model is used to confirm and investigate distinct failure modes observed in experimental investigations. The discussion is limited to shallow beams, where shear deformations are neglected.
Get full access to this article
View all available purchase options and get full access to this article.
References
1.
Arduini, M., Di Tommaso, A., and Nanni, A. ( 1997). “Brittle failure in FRP plate and sheet bonded beams.” ACI Struct. J., 94(4), 363–369.
2.
Arduini, M., and Nanni, A. (1997). “Behavior of precracked RC beams strengthened with carbon FRP sheets.”J. Compos. for Constr., ASCE, 1(2), 63–70.
3.
Bathe, K. J. ( 1996). Finite element procedures, Prentice-Hall, Upper Saddle River, N.J.
4.
Chajes, M. J., Finch, W. W., Jr. Januszka, T. F., and Thomson, T. A., Jr. ( 1996). “Bond and force transfer of composite material plates bonded to concrete.” ACI Struct. J., 93(2), 208–217.
5.
Hollaway, L. C., and Leeming, M. B. ( 1999). Strengthening of reinforced concrete structures, CRC, London.
6.
Hörmann, M. ( 1997). “Post strengthening of concrete structures by externally bonded fiber reinforced polymers.” Diploma thesis, Inst. of Struct. Mech., University of Stuttgart, Stuttgart, Germany.
7.
Kent, D. C., and Park, R. (1971). “Flexural members with confined concrete.”J. Struct. Div., ASCE, 97, 1964–1990.
8.
Malek, A. M., Saadatmanesh, H., and Ehsani, M. R. ( 1998). “Prediction of failure load of RC beams strengthened with FRP plate due to stress concentration at the plate end.” ACI Struct. J., 95(1), 142–152.
9.
Menegotto, M., and Pinto, P. E. ( 1973). “Method of analysis for cyclically loaded reinforced concrete plane frames including changes in geometry and nonelastic behavior of elements under combined normal force and bending.” Proc., IABSE Symp. on Resistance and Ultimate Deformability of Struct. Acted on by Well-Defined Repeated Loads, IABSE, Zurich, 112–123.
10.
Monti, G., and Spacone, E. (2000). “Reinforced concrete fiber beam element with bond-slip.”J. Struct. Engrg., ASCE, 126(6), 654–661.
11.
Oehlers, D. J., and Moran, J. P. (1990). “Premature failure of externally plated reinforced concrete beams.”J. Struct. Engrg., ASCE, 116(4), 978–995.
12.
Rabinovitch, O., and Frostig, Y. (2000). “Closed-form high-order analysis of RC beams strengthened with FRP strips.”J. Compos. for Constr., ASCE, 4(2), 65–74.
13.
Roberts, T. M. ( 1989). “Approximate analysis of shear and normal stress concentrations in the adhesive layer of plated RC beams.” The Struct. Engrg., 67(12), 229–233.
14.
Rubiano-Benavides, N. R. ( 1998). “Predictions in the inelastic seismic response of concrete structures including shear deformations and anchorage slip.” PhD dissertation, Dept. of Civi. Engrg., University of Texas, Austin, Tex.
15.
Saadatmanesh, H., and Ehsani, M. R. (1991). “RC beams strengthened with GFRP plates. I: Experimental study.”J. Struct. Engrg., ASCE, 117(11), 3417–3433.
16.
Saadatmanesh, H., and Malek, A. M. (1998). “Design guidelines for flexural strengthening of RC beams with FRP plates.”J. Compos. for Constr., ASCE, 2(4), 158–164.
17.
Spacone, E., Filippou, F. C., and Taucer, F. F. ( 1996). “Fiber beam-column model for nonlinear analysis of R/C frames. Part I: Formulation.” Earthquake Engrg. and Struct. Dyn., 25, 711–725.
18.
Spacone, E., and Limkatanyu, S. ( 2000). “Response of reinforced concrete members including bond-slip effects.” ACI Struct. J., 97(6), 831–839.
19.
Täljsten, B. (1997). “Strengthening of beams by plate bonding.”J. Mat. in Civ. Engrg., ASCE, 9(4), 206–212.
20.
Taylor, R. L. ( 1999). FEAP: A Finite Element Analysis Program User manual: Version 7.1, Dept. of Civ. and Envir. Engrg., University of California, Berkeley, Calif., 〈http://www.ce.berkeley.edu/∼rlt/feap/〉.
21.
Zarnic, R., Gostic, S., Bosiljkov, V., and Bokan-Bosiljkov, V. ( 1999). “Improvement of bending load-bearing capacity by externally bonded plates.” Proc., Creating with Concrete, R. K. Dhir and N. A. Henderson, eds., Thomas Telford, London, 433–442.
Information & Authors
Information
Published In
History
Received: Jan 23, 2001
Published online: Dec 1, 2001
Published in print: Dec 2001
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.