Process of debonding in RC beams shear-strengthened with FRP U-strips or side strips

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

Research output: Journal article publicationJournal articleAcademic researchpeer-review

50 Citations (Scopus)


Reinforced concrete (RC) beams may be strengthened for shear using externally bonded fiber reinforced polymer (FRP) composites in the form of side bonding, U-jacketing or complete wrapping. The shear failure of almost all RC beams shear-strengthened with side bonded FRP and the majority of those strengthened with FRP U-jackets, is due to debonding of the FRP. The bond behavior between the externally-bonded FRP reinforcement (referred to as FRP strips for simplicity) and the concrete substrate therefore plays a crucial role in the failure process of these beams. Despite extensive research in the past decade, there is still a lack of understanding of how debonding of FRP strips in such a beam propagates and how the debonding process affects its shear behavior. This paper presents an analytical study on the progressive debonding of FRP strips in such strengthened beams. The complete debonding process is modeled and the contribution of the FRP strips to the shear capacity of the beam is quantified. The validity of the analytical solution is verified by comparing its predictions with numerical results from a finite element analysis. This analytical treatment represents a significant step forward in understanding how interaction between FRP strips, steel stirrups and concrete affects the shear resistance of RC beams shear-strengthened with FRP strips.
Original languageEnglish
Pages (from-to)1266-1282
Number of pages17
JournalInternational Journal of Solids and Structures
Issue number10
Publication statusPublished - 15 May 2012


  • Debonding
  • Fiber reinforced polymers (FRP)
  • Interfacial stress
  • Reinforced concrete beams
  • Shear failure
  • Shear resistance
  • Strengthening
  • Stress distribution

ASJC Scopus subject areas

  • Mechanical Engineering
  • Mechanics of Materials
  • Materials Science(all)
  • Condensed Matter Physics
  • Applied Mathematics
  • Modelling and Simulation


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