Structural Engineering and Mechanics

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Interfacial stress assessment at the cracked zones in CFRP retrofitted RC beams

  • Received : 2011.08.01
  • Accepted : 2012.11.01
  • Published : 2012.12.25
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Abstract

In this work, an experimental examination was carried out to study interfacial stresses developed at the junction zones between carbon fiber reinforced plastic (CFRP) fabrics (~1 mm thickness) and tensile concrete portion in CFRP retrofitted RC beams. In this respect, initially six similar RC beams of $150{\times}150{\times}1000mm$ dimensions were prepared. Three of which were strengthened with CFRP fabrics at the tensile side of the beams. Furthermore, a notch was cut at the center of the bottom surface for all of the studied beams. The notch was 15 mm deep and ran across the full width of tension side of the beams. The mentioned interfacial stresses could be calculated from strains measured using strain gauges mounted on the interface zone of the tensile concrete and the CFRP sheet. Based on the results obtained, it is shown that interfacial stresses developed between CFRP fabrics and RC beam had a noticeable effect on debonding failure mode of the latter. The load carrying capacity of CFRP strengthened RC specimens increased ~75% compared to that of the control RC beams. This was attributed to the enhancement of flexural mode of the former. Finally, finite element analysis was also utilized to verify the measured experimental results.

Keywords

References

  1. ACI (2008), "Building code requirements for structural concrete and commentary (ACI 318-11)", American Concrete Institute, Farmington Hills, MI48331, USA.
  2. Bizindavyi, L. and Neale, K.W. (1999), "Transfer lengths and bond strengths for composites bonded to concrete", J. Compos. Constr., 3(4), 153-160. https://doi.org/10.1061/(ASCE)1090-0268(1999)3:4(153)
  3. Duthinh, D. and Starnes, M. (2004), "Strength and ductility of concrete beams reinforced with CFRP plates and steel", J. Compos. Constr., ASCE, 8(1), 59-69. https://doi.org/10.1061/(ASCE)1090-0268(2004)8:1(59)
  4. Hu, H.T., Lin, F.M. and Jan, Y.Y. (2004), "Nonlinear finite element analysis of reinforced concrete beams strengthened by fiber-reinforced plastics", J. Compos. Constr., ASCE, 63(3-4), 271-281.
  5. Huang, J. and Huang, P. (2011), "Three-dimensional numerical simulation and cracking analysis of fiberreinforced cement-based composites", Comput. Concrete, 8(3), 327-341. https://doi.org/10.12989/cac.2011.8.3.327
  6. Goloti, V., Spadea, G. and Swamy, R. N. (2004), "Structural model to predict the failure behavior of plated reinforced concrete beams", J. Compos. Constr., ASCE, 8(2), 104-122. https://doi.org/10.1061/(ASCE)1090-0268(2004)8:2(104)
  7. Jones, R., Swamy, R.N. and Bouderbalah, A. (1980), "Composite behavior of concrete beams with epoxy bonded external reinforcement", Int. J. Cement Compos., 2(2), 91-107.
  8. Kabir, M.Z. and Hojatkashani, A. (2008), "A comparison between finite element and analytical solutions of interfacial stress distribution in a RC beam retrofitted with FRP composite", Int. J. Sci. Technol. Amirkabir, 19, 55-63.
  9. Labossiere, P., Neale, K.W. and Rochette, P. (2000), "Fiber reinforced polymer strengthening of the Saint- Emelie-de-l Energie Bridge: design, instrumentation, and field testing", Can. J. Civil Eng., 27(5), 916-927. https://doi.org/10.1139/l00-028
  10. Lau, K.T., Dutta, P.K., Zhou, L.M. and Hui, D. (2001), "Mechanics of bounds in an FRP bounded concrete beam", J. Compos., Part B: Eng., 32, 491-502. https://doi.org/10.1016/S1359-8368(01)00032-4
  11. Leung, C.K.Y. (2001), "Delamination failure in concrete beams retrofitted with a bonded plate", J. Mater. Civil Eng., 13(2), 106-113. https://doi.org/10.1061/(ASCE)0899-1561(2001)13:2(106)
  12. Macgregor, L.G. (2000), Modified Hognestad Model for the Compressive Concrete, Reinforced Concrete Mechanics and Design, Prentice-Hall, NJ.
  13. Meier, U. (1997), "Post strengthening by continuous fiber laminates in Europe", Non-metallic(FRP) Reinforcement for Concrete Structures, Vol. 1, Japan Concrete Institute, 41-56.
  14. Oehlers, D.J. and Moran, J.P. (1990), "Premature failure of externally plated reinforced concrete beams", J.Struct. Eng., 116(4), 978-995. https://doi.org/10.1061/(ASCE)0733-9445(1990)116:4(978)
  15. Owen, D.R.J., Figueiras, J.A. and Damjanic, F. (1983), "Finite element analysis of reinforced and prestressed concrete structures including thermal loading", Comput. Meth. Appl. Mech. Eng., 41(3), 323-366. https://doi.org/10.1016/0045-7825(83)90012-9
  16. Quantrill, R.J., Hollaway, L.C. and Thorne, A.M. (1996), "Prediction of the maximum plate and stresses of FRP strengthened beams", Mag. Concrete Res., 48(177), 343-351. https://doi.org/10.1680/macr.1996.48.177.343
  17. Smith, S.T. and Teng, J.G. (2001), "Interfacial stresses in plated beams", J. Eng. Struct., 23, 857-871. https://doi.org/10.1016/S0141-0296(00)00090-0
  18. Teng, J.G., Chen, J.F., Smith, S.T. and Lam, L. (2002), FRP-Strengthened RC Structures, John Wiley & Sons, West Sussex, England.
  19. Teng, J.G., Lu, X.Z. and Jiang, J.J. (2005), "Bond-slip models for FRP sheet bonded to concrete", J. Eng. Struct., 27(6), 920-937. https://doi.org/10.1016/j.engstruct.2005.01.014
  20. Triantafillou, T.C. and Plevris, N. (1992), "Strengthening of RC beams with epoxy bonded fiber composite materials", Mat. Struct., 25, 201-211. https://doi.org/10.1007/BF02473064
  21. Van Gemert, D. (1980), "Repairing of concrete structures by externally bonded steel plates", Int. J. Adhesion, 2, 67-72.
  22. Zibara, Y.N., Baluch, M.H. and Sharif, A.M. (1995), "Combined experimental-numerical approach to the characterization of the steel-glue-concrete interface", Mat. Struct., 28, 518-525. https://doi.org/10.1007/BF02473156
  23. Zou, Y. and Huchelbridge, P.E. (2007), "Simulation of crack growth in FRP reinforced concrete", J. Bridge Eng., ASCE, 12(2), 237-245. https://doi.org/10.1061/(ASCE)1084-0702(2007)12:2(237)
  24. Mander, J.B., Priestley, M.J.N. and Park, R. (1988), "Theoretical stress-strain model for confined concrete", J. Struct. Eng., ASCE, 114(8), 1804-1826. https://doi.org/10.1061/(ASCE)0733-9445(1988)114:8(1804)

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