Finite element analysis of width effect in interface debonding of FRP plate bonded to concrete

Tao Xu, Zhujie He, Chunan A Tang, Wancheng Zhu, Ranjith Pathegama Gamage

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A three-dimensional meso-mechanical model to study the debonding of FRP-to-concrete is described and then verified in this paper. The influence of the width of the FRP on the load-carrying capacity is investigated to understand the debonding mechanism of failure in such systems. Numerical simulations show that the progressive debonding of FRP plate bonded to concrete occurring beneath the FRP plate can be divided into four stages: elastic-deformation stage, the elastic-softening stage, the elastic-softening-debonded stage and softening-debonded stage. The numerical simulations indicate the development of high stress/strain gradients at the interface as a consequence of the relative slip between the FRP and the concrete. With the increase of the width of FRP plate, the interfacial bond strength and the slope of the initial elastic deformation of the load-global slip of FRP-to-concrete increases, the global slip is lower when increasing FRP width at the same stress level, by contrast, the total ultimate interfacial slip decreases with the increase of FRP plate width, and the interfacial ductility of FRP-to-concrete and the utilization efficiency of FRP plate also reduce. The reinforcement efficiency of the bonding of FRP plate in strips is higher than that of the bonding of FRP plate as a whole. In addition, the bending stress is of significant influence on the maximum principal stress at the loading end and near the plate edge and the debonding of FRP-to-concrete starts in the concrete beneath FRP plate near the edge of FRP plates and loading end. Numerical results on debonding of FRP-concrete visually reproduce the temporal evolution and spatial distribution of microcracking in FRP-to-concrete and reveal the distribution patterns of stress and strain in FRP plate and concrete, which is in good agreement with the existing experimental results in laboratory. Numerical simulations show that the numerical approach in the present study provides a useful tool for enhancing our understanding of debonding failure process and mechanism of FRP-concrete and our ability to predict mechanical performance and reliability of these FRP plate bonded to concrete structures.
Original languageEnglish
Pages (from-to)30 - 41
Number of pages12
JournalFinite Elements in Analysis and Design
Issue numberC
Publication statusPublished - Jan 2015


  • FRP plate
  • Concrete
  • Debonding
  • Width ratio
  • Failure process

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