Pull-out and shear-strength models for FRP spike anchors

Spike anchors are a promising way to enhance the maximum capacity and post-peak load-strain response of externally-bonded fibre-reinforced polymer (FRP) materials for retrofitting of concrete structures. Although laboratory testing has proven the effectiveness of these spike anchors (also known as fan anchors), little work has been conducted to provide an analytical basis on which to rely on such anchorage systems. For instance, which parameters govern the behaviour of these anchors? Without an analytical or predictive basis for the behaviour of such anchors, their use will be limited. Therefore, this paper presents an analytical model to be able to predict the behaviour of such anchors, by including important geometrical and installation parameters. This model will, for the first time, allow engineers to specify, with confidence, the use of spike anchors as a method to anchor FRP sheets and plates to structural concrete members.