Fibre-reinforced polymer (FRP)-to-concrete joints anchored with FRP anchors: tests and experimental trends

This paper reports an investigation on the influence of anchors made from fibre-reinforced polymer (herein FRP anchors) when applied to FRP-to-concrete bonds. The experimental section of the paper consists of 44 tests on FRP-to-concrete joints of which 20 joints are unanchored controls and 24 joints are anchored with FRP anchors. The influence of plate width, plate thickness and plate elastic modulus are considered as these parameters have received little to no attention to date. An increase in plate width is shown to considerably enhance the joint strength although the influence of the anchor decreases. The other two test parameters are shown to be less influential. The analytical section of the paper involves regression modelling of components of a large test database on FRP-to-concrete joints anchored with FRP anchors compiled elsewhere by the authors. The models, which are calibrated in best-fit and design forms, allow experimental trends to be readily observed and quantified within the bounds of the experimental data for three influential parameters of plate length, angle of anchor insertion, and plate width. Finally, a combined regression model is proposed and it is evaluated with tests on FRP-to-concrete joints anchored with multiple anchors.