Stress-strain Behavior of Steel Rebars Embedded in FRP-Confined Concrete Including Bulking

Jian-Guo Dai, Yulei Bai

Research output: Unpublished conference presentation (presented paper, abstract, poster)AbstractAcademic research


Buckling of steel rebars usually causes a sudden loss of the load-carrying capacity and the ultimate state of conventional reinforced concrete (RC) columns under seismic loading. As a result, the buckling behavior of steel rebars has been investigated in numerous experimental and theoretical studies. Over the past few decades, the use of fiber-reinforced polymer (FRP) confining jackets has become an attractive solution for the seismic retrofit of RC columns. It is expected that reinforcing bars behave differently in fiber-reinforced polymer (FRP)-confined RC columns due to the lateral confinement effect of FRP. However, very limited modeling work has been conducted on the buckling behavior of steel reinforcement in FRP-confined concrete columns although it is generally thought that the FRP confinement can inhibit or delay the buckling process of steel rebars.

This paper presents a summary of a research project carried out in the authors’ group on the stress-strain behavior of steel rebars embedded in FRP-confined concrete including buckling. The work presented here consists of three parts: (1) experimental tests of FRP-confined RC columns subjected to monotonic and cyclic compressive loading with the aim to investigate the interaction between the longitudinal steel rebars and the FRP-confined concrete; (2) theoretical modeling of the buckling behavior of longitudinal steel rebars in FRP-confined concrete and development of a monotonic stress-strain envelope for such steel rebars including the buckling; (3) development of a cyclic compressive stress-strain model for reinforcing bars considering the lateral support provided by the FRP confinement and buckling. All the proposed models have been validated through comparisons with test results. The proposed monotonic envelope and cyclic stress-strain model are expected to serve as a fundamental basis for accurate prediction of strength and ductility of FRP-confined RC columns.
Original languageEnglish
Number of pages1
Publication statusPublished - 2017
EventThe 2nd ACF Symposium 2017 “Innovation for Sustainable Concrete Infrastructures” - Chiangmai, Thailand
Duration: 23 Nov 201725 Nov 2017


Forum/SymposiumThe 2nd ACF Symposium 2017 “Innovation for Sustainable Concrete Infrastructures”


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