Phased Nonlinear Finite-Element Analysis of Precracked RC T-Beams Repaired in Shear with CFRP Sheets

Samir Dirar, Janet M. Lees, Chris Morley

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)
310 Downloads (Pure)


Phased nonlinear finite-element (FE) analyses were carried out to predict the behavior of precracked reinforced concrete (RC) T-beams repaired in shear with externally bonded (EB) carbon fiber-reinforced polymer (CFRP) sheets and subjected to two loading patterns (LPs). Appropriate constitutive relationships were employed to model the behavior of concrete, internal steel reinforcement, EB CFRP reinforcement, and CFRP-to-concrete interface and consequently predict the structural behavior and capture the failure modes of the strengthened beams. Three constitutive models for the behavior of concrete in shear were evaluated, namely, a total strain rotating crack model and two fixed-angle crack models with either constant or variable shear retention factors. The majority of published FE studies have considered rectangular sections that were strengthened before testing. The key feature of the FE models presented in this paper is the use of the phased analysis technique to model realistically the process of strengthening RC T-beams under load and predict the structural response of the beams to different loading patterns. Furthermore, the paper provides insight into and evaluates the accuracy of the three concrete shear models named above. A detailed comparison between the numerical and experimental results included the shear forces at failure, shear force-deflection curves, crack patterns, failure modes, and strains in the internal steel and external CFRP shear reinforcement. The FE models predicted the experimental shear force capacities and crack patterns with sufficient accuracy but underestimated the post-repair stiffness for the beams subjected to Loading Pattern 1 and overestimated the strain in the CFRP sheets.
Original languageEnglish
Pages (from-to)476-487
Number of pages12
JournalJournal of Composites for Construction
Issue number4
Early online date17 Oct 2012
Publication statusPublished - 1 Jul 2013


  • Concrete beams
  • Cracking
  • Fiber reinforced polymers
  • Finite element method
  • Reinforced concrete
  • Rehabilitation
  • Retrofitting
  • Shear Strength
  • Sheets

ASJC Scopus subject areas

  • Civil and Structural Engineering


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