Intermediate crack debonding in FRP-strengthened RC beams: FE analysis and strength model

X. Z. Lu, Jinguang Teng, L. P. Ye, J. J. Jiang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

157 Citations (Scopus)


Reinforced concrete (RC) beams strengthened in flexure with a bonded fiber-reinforced polymer (FRP) plate may fail by intermediate crack (IC) debonding, in which debonding initiates at a critical section in the high moment region and propagates to a plate end. This paper first presents a finite-element (FE) model based on the smeared crack approach for concrete for the numerical simulation of the IC debonding process. This finite-element model includes two novel features: (1) the interfacial behavior within the major flexural crack zone is differentiated from that outside this zone and (2) the effect of local slip concentrations near a flexural crack is captured using a dual local debonding criterion. The FE model is shown to be accurate through comparisons with the results of 42 beam tests. The paper also presents an accurate and simple strength model based on interfacial shear stress distributions from finite-element analyses. The new strength model is shown to be accurate through comparisons with the test results of 77 beams, including the 42 beams used in verifying the FE model, and is suitable for direct use in design.
Original languageEnglish
Pages (from-to)161-174
Number of pages14
JournalJournal of Composites for Construction
Issue number2
Publication statusPublished - 23 Mar 2007


  • Bonding
  • Concrete beams
  • Concrete, reinforced
  • Cracking
  • Fiber reinforced polymers
  • Finite element method

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Ceramics and Composites
  • Mechanics of Materials
  • Computational Mechanics

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