Energy-Based Modeling Approach for Debonding of FRP Plate from Concrete Substrate
Publication: Journal of Engineering Mechanics
Volume 132, Issue 6
Abstract
For concrete beams and slabs strengthened with bonded fiber reinforced plastic (FRP) plates, plate debonding from the concrete substrate is a common failure mode. In this paper, the debonding process is modeled as the propagation of a crack along the concrete/adhesive interface, with frictional shear stress acting behind the crack tip. Crack propagation is taken to occur when the net energy release of the system equals the interfacial fracture energy. The analysis is first performed for the special case with constant shear stress along the debonded interface, and then for the general case with slip softening in the debonded zone. From the results, a direct correspondence between energy-based and strength-based analyses can be established for arbitrary softening behavior along the interface. Specifically, through the proper definition of an effective interfacial shear strength, the conventional strength-based approach can be employed to give the same results as the much more complicated energy-based analysis. Also, based on the relation between the effective shear strength and other material parameters, it is possible to explain the very high interfacial shear stresses observed in experimental measurements. As an application example, distribution of plate stress and interfacial shear stress for the linear softening case is derived. The model results are found to be in good agreement with experimental measurements, showing that the simple linear softening model can describe the debonding process in real material systems.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
Financial support of the work by the Hong Kong Research Grant Council, under Grant No. UNSPECIFIEDCERG UST6252/02E as well as the assistance of Mr. Jinlong Pan in generating some of the figures in the paper, are gratefully acknowledged.
References
Arduini, M., Di Tommaso, A., and Nanni, A. (1997). “Brittle failure in FRP plate and sheet bonded beams.” ACI Struct. J., 94(4), 363–370.
Bizindavyi, L., and Neale, K. (1999). “Transfer lengths and bond strengths for composites bonded to concrete.” J. Compos. Constr., 3(4), 153–160.
Brosens, K., and Van Gemert, D. (1998). “Plate end shear design for external CFRP laminates.” Fracture mechanics of concrete structures, H. Mihashi and K. Rokugo, eds., AEDIFICATIO, Freiburg, 1793–1804.
Budianski, B., Hutchinson, J. W., and Evans, A. G. (1986). “Matrix fracture in fiber-reinforced ceramics.” J. Mech. Phys. Solids, 34(2), 167–189.
Buyukozturk, O., and Hearing, B. (1998). “Failure behavior of precracked concrete beams retrofitted with FRP.” J. Compos. Constr., 2(3), 138–144.
FIB (2001). “Externally bonded FRP reinforcement for RC structures.” Technical Rep. Prepared by fib Task Group 9.3 on FRP Reinforcement for Concrete Structures, FIB, Lausanne, Switzerland.
Gao, Y., Mai, Y. W., and Cotterell, B. (1988). “Fracture of fiber-reinforced materials.” ZAMP, 39(4), 550–572.
Holzenkampfer, K. (1994). “Ingenieurmodelle des verbundes geklebter bewehrung fur betonbauteile.” Dissertation, TU Braunschweig, Braunschweig, Germany.
Khalifa, A., Gold, W. J., Nanni, A., and Abdel Aziz, A. (1998). “Contribution of externally bonded FRP to shear capacity of RC flexural members.” J. Compos. Constr., 2(4), 195–202.
Leung, C. K. Y. (1992). “Fracture-based two-way debonding model for discontinuous fibers in elastic matrix.” J. Eng. Mech., 118(11), 2298–2318.
Leung, C. K. Y. (2001). “Delamination failure in concrete beams retrofitted with a bonded plate.” J. Mater. Civ. Eng., 13(2), 106–113.
Leung, C. K. Y., Klenke, M., Tung, W. K., and Luk, H. C. Y. (2000). “Investigation of nonlinear behaviour for concrete beams retrofitted with composite plate.” Brittle matrix composites 6, A. M. Brandt, V. C. Li, and I. H. Marshall, eds., Woodhead, Cambridge, England, 286–295.
Leung, C. K. Y., Klenke, M., Tung, W. K., and Luk, H. C. Y. (2006). “Determination of nonlinear softening behavior at FRP composite/concrete interface.” J. Eng. Mech., 132(5), 498–508.
Leung, C. K. Y., and Tung, W. K. (2006). “Three-parameter model for debonding of FRP plate from concrete substrate.” J. Eng. Mech., 132(5), 509–518.
Meier, U. (1995). “Strengthening of structures using carbon fibre/epoxy composites.” Constr. Build. Mater., 9, 341–353.
Neubauer, U., and Rostasy, F. S. (1997). “Design aspects of concrete structures strengthened with externally bonded CFRP plates.” Proc. 7th Int. Conf. on Structural faults and Repairs, M. C. Forde, ed., Edinburgh, U.K., 109–118.
Stang, H., Li, Z., and Shah, S. P. (1990). “Pull-out problem: Stress versus fracture mechanical approach.” J. Eng. Mech., 116(10), 2136–2150.
Taljsten, B. (1996). “Strengthening of concrete prisms using the plate bonding technique.” Int. J. Fract., 82, 253–266.
Teng, J. G., Lam, L., Chan, W., and Wang, J. (2000). “Retrofitting of deficient RC cantilever slabs using GFRP strips.” J. Compos. Constr., 4(2), 75–84.
Triantafillou, T. C. (1998). “Shear strengthening of reinforced concrete beams using epoxy-bonded FRP composites.” ACI Struct. J., 95(2), 107–115.
Wu, Z., Matsuzaki, T., and Tanabe, K. (1997). “Interface crack propagation in FRP-strengthened concrete structures.” Non-Metallic (FRP) reinforcement for concrete structures, Vol. 1, Japan Concrete Institute, Sapporo, Japan, 319–326.
Wu, Z., Yuan, H., and Niu, H. (2002). “Stress transfer and fracture propagation in different kinds of adhesive joints.” J. Eng. Mech., 128(5), 562–573.
Yuan, H., Wu, Z. S., and Yoshizawa, H. (2001). “Theoretical solutions on interfacial stress transfer of externally bonded steel/composite laminates.” JSCE J. Struct. Mech. Earthquake Eng., 675(1–55), 27–39.
Information & Authors
Information
Published In
Journal of Engineering Mechanics
Volume 132 • Issue 6 • June 2006
Pages: 583 - 593
Copyright
© 2006 ASCE.
History
Received: Oct 23, 2003
Accepted: Jul 5, 2005
Published online: Jun 1, 2006
Published in print: Jun 2006
Notes
Note. Associate Editor: Franz-Josef Ulm
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.