Skip to main content

Shear-strengthening of reinforced & prestressed concrete beams using FRP: Part II — Experimental investigation


The main objectives of this research were to experimentally evaluate the impact of Carbon Fiber-Reinforced Polymers (CFRP) amount and strip spacing on the shear behavior of prestressed concrete (PC) beams and to evaluate the applicability of existing analytical models of Fiber-Reinforced Polymer (FRP) shear capacity to PC beams shear-strengthened with CFRP. The Ushaped CFRP strips with different spacing were applied externally to the test specimens in order to observe the overall behavio r of the prestressed concrete I-beams and the mode of failure of the applied CFRP strips. Results obtained from the experimental program showed that the application of CFRP strips to prestressed concrete I-beams did in fact enhance the overall behavior of the specimens. The strengthened specimens responded with an increase in ductility and in shear capacity. However, it should be noted that the CFRP strips were not effective at all at spacing greater than half the effective depth of the specimen and that fracture of the strips was the dominant failure mechanism of CFRP. Further research is needed to confirm the conclusion derived from the experimental program.


  1. Khalifa, A. and Nanni, A., “Rehabilitation of Rectangular Simply Supported RC Beams with Shear Deficiencies Using CFRP Composites,” Construction and Building Materials, Vol. 16, No. 3, 2002, pp. 135–146.

    Article  Google Scholar 

  2. Kansara, K. D., Ibell, T. J., Darby, A. P., and Everden, M., “Interpreting Conservativeness in Design Criteria for Flexural Strengthening of RC Structures Using Externally Bonded FRP,” International Journal of Concrete Structures and Materials, Vol. 4, No. 1, 2010, pp. 25–36.

    Article  Google Scholar 

  3. Ibrahim Ary, M. and Kang, T. H.-K., “Shear-Strengthening of Reinforced & Prestressed Concrete Beams Using FRP: Part I — Review of Previous Research,” International Journal of Concrete Structures and Materials, Vol. 6, No. 1, 2012.

  4. Ibrahim Ary, M.,“Shear Strengthening of Prestressed Concrete I-Beams Using Carbon Fiber-Reinforced Polymers,” Master’s thesis, School of Civil Engineering and Environmental Science, The University of Oklahoma, Norman, 2011, 96 pp.

    Google Scholar 

  5. Triantafillou, T. C. and Antonopoulos, C. P., “Design of Concrete Flexural Members Strengthened in Shear with FRP,” ASCE Journal of Composites for Construction, Vol. 4, No. 4, 2000, pp. 198–205.

    Article  Google Scholar 

  6. Bousselham, A. and Chaallal, O., “Shear Strengthening of Reinforced Concrete Beams with Fiber-Reinforced Polymer: Assessment of Influencing Parameters and Required Research,” ACI Structural Journal, Vol. 101, No. 2, 2004, pp. 219–227.

    Google Scholar 

  7. Sas, G., Täljsten, B., Barros, J., Lima, J., and Carolin, A., “Are Available Models Reliable for Predicting the FRP Contribution to the Shear Resistance of RC Beams?,” ASCE Journal of Composites for Construction, Vol. 13, No. 6, 2009, pp. 514–534.

    Article  Google Scholar 

  8. ACI Committee 318, “Building Code Requirements for Structural Concrete (ACI 318-08) and Commentary,” American Concrete Institute, Farmington Hills, MI, 2008, 473 pp.

  9. ASTM, “American Society for Testing and Materials Annual Book of ASTM Standards,” Vol. 04.09, West Conshohocken, PA, 2008.

  10. ACI Committee 440, “Guide for the Design and Construction of Externally Bonded FRP Systems for Strengthening Concrete Structures (ACI 440.2R-08),” American Concrete Institute, Farmington Hills, MI, 2008, 76 pp.

Download references

Author information

Authors and Affiliations


Corresponding author

Correspondence to Thomas H. -K. Kang.

Rights and permissions

Open Access This article is distributed under the terms of the Creative Commons Attribution 2.0 International License ( ), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Reprints and Permissions

About this article

Cite this article

Kang, T.H.K., Ary, M.I. Shear-strengthening of reinforced & prestressed concrete beams using FRP: Part II — Experimental investigation. Int J Concr Struct Mater 6, 49–57 (2012).

Download citation

  • Published:

  • Issue Date:

  • DOI:


  • FRP
  • prestressed concrete
  • shear
  • strengthening
  • rehabilitation