Estimating Shear-Transfer Resistance When Using Glass Fiber-Reinforced Polymer Reinforcement

Design codes base the behavior of the shear-friction interface on two models: the basic shear friction model and the cohesion plus friction model. These models have been developed using steel as the reference reinforcing material and they have extended to design provisions when using glass fiber-reinforced polymer (GFRP) materials. However, when using GFRP reinforcement, where yielding does not happen, a different ultimate limit state needs to be introduced. Accordingly, additional data and analysis are required to validate and improve the proposed models and to verify what implications they have on design when specifying GFRP materials. In this research, a study was conducted based on previous experimental data on the contribution of GFRP bars to the mechanism of shear transfer by using the pushoff test. Through a multiple linear-regression analysis, a mathematical model introducing new parameters that accurately capture the behavior of this material with respect to shear-transfer phenomena in concrete structures is presented in this paper. The findings of this study provide new insights into the behavior of the shear-friction mechanism with GFRP reinforcement, suggesting potential updates for current design codes and guide specifications.