Abstract
This paper presents finite element (FE) modeling of the debonding behavior of fiber reinforced polymer (FRP)-to-concrete interfaces subject to mixed-mode loading, which is realized through a peeling test of FRP composites externally bonded onto a concrete substrate. A cohesive zone model (CZM) is implemented into the FE model to represent the behavior of the FRP-to-concrete interface. Two element schemes (orthotropic plane stress element and beam element) were employed to simulate the behavior of FRP composite plate in the peeling test. The orthotropic plane stress element scheme, bearing a clear physical background and with an easy definition of the material property parameters following the composite mechanics, is found to be superior to the beam element scheme, and thus is utilized to conduct parametric studies. The influences of the peeling angle, the interfacial parameters (i.e., the configuration of the cohesive zone models, the interfacial damage initiation law (DIL), the interfacial damage evolution law (DEL), the coupling of mode-I and mode-II components), on the mixed-mode failure of the FRP-concrete-interface are carefully investigated. The results showed that the mode I component plays a critical role in the debonding failure of FRP-to-concrete interfaces even when the peeling angle is very small. The failure of FRP-to-concrete interface transits promptly from a mode II-dominated one to a mode I-dominated one when the peeling angle increases to a relatively small value (e.g., 4 degree) and subsequently the peeling force (i.e., the debonding strength of FRP) decreases dramatically. Such mixity of the mode I and mode II components should be appropriately considered for refining the analysis of FRP-strengthened RC beams and the FRP debonding strength design, for which a pure mode II interfacial failure was usually assumed.
Highlights
Bonded fiber reinforced polymer (FRP) plates or sheets are widely recognized as an effective technique for strengthening reinforced concrete (RC) structures [1,2,3,4]
[5]), whichfailure correspond an interface subjected to aintension action, a shearclassified action andinto a combined of thetoFRP-to-concrete interface fact can be three action of tension and shear, respectively
The effect of mode I component is usually ignored in the current code of practice when predicting the mode II debonding strength of FRP in FRP-flexurally strengthened RC beams. This may not be true because even a very small shear deformation may lead to a large peeling angle locally and a mode I dominant FRP debonding failure at the toe of any diagonal crack, since the ability of the FRP-to-concrete interface in tolerating the mode I
Summary
Bonded fiber reinforced polymer (FRP) plates or sheets are widely recognized as an effective technique for strengthening reinforced concrete (RC) structures [1,2,3,4]. Both lead to normal and/or shear stress concentration at the FRP-to-concrete interface This to utilize efficiently the FRP strength while keeping the concrete un-cracked unless the concrete paper deals with the latter discontinuity, which is believed to be more critical, since it is impossible is prestressed. The effect of mode I component is usually ignored in the current code of practice when predicting the mode II debonding strength of FRP in FRP-flexurally strengthened RC beams This may not be true because even a very small shear deformation may lead to a large peeling angle locally and a mode I dominant FRP debonding failure at the toe of any diagonal crack (i.e., a flexural/shear crack), since the ability of the FRP-to-concrete interface in tolerating the mode I deformation is weak.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
