On Edge Stresses Control in Strengthened RC Beams with FRP Strips: Adhesive Layer Profile Effect
Publication: Journal of Engineering Mechanics
Volume 127, Issue 4
Abstract
A high-order analytical model for the analysis of reinforced concrete (RC) beams strengthened with fiber-reinforced plastic (FRP) strips bonded with adhesive layer of variable thickness is presented. The model is based on the closed-form high-order approach, and it provides the means for the analysis of beams retrofitted with generally curved FRP strips and adhesive layers of arbitrary profile. The analysis is comprehensive and includes the local and overall response of the structure. An emphasis is put on the stress concentration that occurs at the edge of the FRP strip and in many cases leads to brittle and sudden failure of the strengthened member. The field equations and the boundary and continuity conditions are derived using the variational principle of virtual work along with the kinematic relations of small deformations. The governing equations of the generally curved FRP strip include large curvatures and are introduced via coordinate transformation from its local curvilinear system into the global Cartesian one. The derived model is used for the investigation of various adhesive profiles and their influence on the shear and vertical normal stresses at the edges of the FRP strip. The results focus on the stress concentrations involved and reveal that proper design and application of the adhesive profile can significantly reduce the edge stresses, thus preventing the brittle mode of failure. The paper is concluded with a summary and recommendations for the analysis, design, and application of the strengthening process.
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References
1.
Adam, R. D., and Wake, W. C. ( 1984). Structural adhesive joints in engineering, Elsevier Applied Science Publishers, Essex, England.
2.
Arduini, M., Di Tommaso, A., and Nanni, A. ( 1997). “Brittle failure in FRP plate and sheet bonded beams.” ACI Struct. J., 94(4), 363–371.
3.
Arduini, M., and Nanni, A. ( 1997). “Parametric study of beams externally bonded FRP reinforcements.” ACI Struct. J., 94(5), 493–501.
4.
Buyukozturk, O., and Hearing, B. (1998). “Failure behavior of precracked concrete beams retrofitted with FRP.”J. Compos. for Constr., ASCE, 2(3), 138–144.
5.
Daniel, J. W. ( 1979). “A road map of methods for approximating solutions of two-point boundary-value problems.” Codes for boundary value problems in ordinary differential equations, B. Childs, M. Scott, J. W. Daniel, E. Denman, and P. Nelson, eds., Springer, Berlin.
6.
Ehsani, R., and Saadatmanesh, H. ( 1990). “Fiber composite plates for strengthening of bridge beams.” Compos. Struct., Oxford, U.K., 15(4), 343–355.
7.
Frostig, Y., Baruch, M., Vilnay, O., and Sheinman, L. (1992). “High-order theory for sandwich beam behavior with transversely flexible core.”J. Engrg. Mech., ASCE, 118(5), 1026–1043.
8.
Frostig, Y., Thomsen, O. T., and Mortensen, F. (1999). “Analysis of adhesive-bonded joints, square-end and spew-fillet high-order theory approach.”J. Engrg. Mech., ASCE, 125(11), 1298–1307.
9.
Jones, R., Swamy, R. N., Bloxham, J., and Bouderbalah, A. ( 1980). “Composite behavior of concrete beams with epoxy bonded external reinforcement.” Int. J. Cement Compos., Hornby, Lancaster, U.K., 2(2), 91–107.
10.
Karam, G. N. ( 1992). “Optimal design for prestressing with FRP sheets in structural members.” Advanced composite materials in bridge and construction, K. W. Neale and P. Labossiere, eds., Canadian Society for Civil Engineering, Quebec, Canada, 277–285.
11.
Meier, U. ( 1997). “Post strengthening by continuous fiber laminates in Europe.” Non-metallic (FRP) reinforcement for concrete structures, Vol. 1, Japan Concrete Institute, Tokyo, 42–56.
12.
Meier, U., Deuring, M., Meier, H., and Schwegler, G. ( 1993). “Strengthening of structures with advanced composites.” Alternative materials for the reinforcement and prestressing of concrete, J. L. Clarke, ed., Chapman & Hall, Glasgow, Scotland, 153–171.
13.
Oehlers, D. J., and Moran, J. P. (1990). “Premature failure of externally plated reinforced concrete beams.”J. Struct. Engrg., ASCE, 116(4), 978–995.
14.
Quantrill, R. J., Hollaway, L. C., and Thorne, A. M. ( 1996). “Experimental and analytical investigation of RP strengthened beam response: Part I, II.” Mag. of Concrete Res., 48(177), 331–351.
15.
Quantrill, R. J., Hollaway, L. C., Thorne, A. M., and Parke, G. A. R. ( 1995). “Preliminary research on the strengthening of reinforced concrete beams using GFRP.” Non-metallic (FRP) reinforcement for concrete structures, L. Taerwe, ed., E & FN Spon, London, 542–550.
16.
Rabinovitch, O., and Frostig, Y. ( 1999). “Edge effects in retrofitting of concrete beams using FRP strips—a closed form high order theory approach.” FRP reinforcement for reinforced concrete structures, C. W. Dolan, S. H. Rizkalla, and A. Nanni, eds., American Concrete Institute, Farmington Hills, Mich., 179–191.
17.
Rabinovich, 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.
18.
Roberts, T. M., and Haji-Kazemi, H. ( 1989). “Theoretical study of the behavior of RC beams strengthened by eternally bonded steel plates.” Proc., Instn. Civ. Engrg., London, 87, Part 2, 39–55.
19.
Stoer, J., and Bulirsch, R. ( 1993). Introduction to numerical analysis, Springer, New York.
20.
Täljsten, B. (1997). “Strengthening of beams by plate bonding.”J. Mat. in Civ. Engrg., ASCE, 9(4), 206–212.
21.
Triantafillou, T. C., and Deskovic, N. (1991). “Innovative prestressing with FRP sheets: Mechanics of short-term behavior.”J. Engrg. Mech., ASCE, 117(7), 1652–1672.
22.
Tumialan, G., Serra, P., Nanni, A., and Belarbi, A. ( 1999). “Concrete over delamination in reinforced concrete beams strengthened with carbon fiber reinforced polymer sheets.” FRP reinforcement for reinforced concrete structures, C. W. Dolan, S. H. Rizkalla, and A. Nanni, eds., American Concrete Institute, Farmington Hills, Mich., 725–735.
23.
Whitney, J. M. ( 1987). Structural analysis of laminated anisotropic plates, Technomic Publishing Co., Lancaster, Pa.
Information & Authors
Information
Published In
Journal of Engineering Mechanics
Volume 127 • Issue 4 • April 2001
Pages: 317 - 325
History
Received: Jun 7, 2000
Published online: Apr 1, 2001
Published in print: Apr 2001
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