Cyclic stress-strain model incorporating buckling effect for steel reinforcing bars embedded in FRP-confined concrete

Yu Lei Bai, Jianguo Dai, Togay Ozbakkaloglu

Research output: Journal article publicationJournal articleAcademic researchpeer-review

37 Citations (Scopus)


However, reinforcing bars behave differently in fiber-reinforced polymer (FRP)-confined RC cylinders due to the lateral confinement effect of FRP. This paper presents a theoretical study into the buckling behavior of longitudinal steel reinforcing bars embedded in FRP-confined concrete subjected to cyclic axial compression. An empirical monotonic compressive stress-strain model considering the buckling effects proposed previously for laterally supported reinforcing bars is extended to a cyclic model by combining the monotonic envelope and the Menegotto-Pinto model accounting for the cyclic loops. The cyclic stress-strain models for both laterally supported reinforcing bars and FRP-confined plain concrete are then implemented into the OpenSees software platform and validated through comparisons with compressive test results on cyclically loaded FRP-confined plain and RC cylinders. The proposed cyclic stress-strain model for laterally supported reinforcing bars is expected to serve as a fundamental model for predicting the seismic behavior of FRP-strengthened RC cylinders with widely-spaced transverse ties under cyclic axial compression, in which case the local buckling of reinforcing bars usually occurs between two adjacent transverse ties.
Original languageEnglish
Pages (from-to)54-66
Number of pages13
JournalComposite Structures
Publication statusPublished - 15 Dec 2017


  • Bar buckling
  • Cyclic model
  • FRP confinement
  • OpenSees
  • Stress-strain model

ASJC Scopus subject areas

  • Ceramics and Composites
  • Civil and Structural Engineering

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