Improved shear strength model for FRP-strengthened RC beams accounting for adverse FRP-steel interaction

G. M. Chen, Jinguang Teng, J. F. Chen

Research output: Chapter in book / Conference proceedingConference article published in proceeding or bookAcademic researchpeer-review


RC beams shear-strengthened with externally-bonded FRP side strips or U-strips usually fail by debonding. As such debonding occurs in a brittle manner at relatively small shear crack widths, some of the internal steel stirrups may not have reached yielding at beam shear failure. Consequently, the internal steel stirrups cannot be fully utilized. This adverse shear interaction between internal steel stirrups and external FRP strips may significantly reduce the benefit of shear-strengthening FRP but has not been considered by any of the existing FRP strengthening design guidelines. In this paper, an improved shear strength model capable of accounting for the effect of the above shear interaction is first presented, in which the unfavorable effect of shear interaction is reflected through a reduction factor (i.e. shear interaction factor). Using a large test database established in the present study, the performance of the proposed model as well as that of three other shear strength models is then assessed. This assessment shows that the proposed shear strength model performs better than the three existing models. The assessment also shows that the inclusion of the proposed shear interaction factor in the existing models can significantly improve their performance.
Original languageEnglish
Title of host publicationProceedings of the 6th International Conference on FRP Composites in Civil Engineering, CICE 2012
PublisherInternational Institute for FRP in Construction (IIFC)
Publication statusPublished - 1 Jan 2012
Event6th International Conference on FRP Composites in Civil Engineering, CICE 2012 - Rome, Italy
Duration: 13 Jun 201215 Jun 2012


Conference6th International Conference on FRP Composites in Civil Engineering, CICE 2012


  • Bonding
  • Concrete beam
  • Fiber reinforced polymer
  • FRP
  • Reinforced concrete
  • Shear failure
  • Shear resistance
  • Shear strength

ASJC Scopus subject areas

  • Polymers and Plastics
  • Civil and Structural Engineering

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