Optimisation of carbon and glass FRP anchor design

The strengthening and repair of reinforced concrete (RC) civil infrastructure with externally bonded fibre-reinforced polymer (FRP) composites is an established technology. One of the limitations of this technology though is the propensity of the FRP to prematurely debond at strains well below its rupture strain. Anchorage of the FRP strengthening is therefore a logical remedy to prevent or delay debonding failure. A promising type of anchor, which is made from bundles of fibre or rolled fibre sheets and can be applied to virtually any shaped structural member, is the FRP anchor. Limited fundamental characterisation of FRP anchors has, however, been undertaken to date. In this paper a series of tests aimed at optimising the FRP anchor design within the confines of the experimental variables are reported. The anchors are tested in an FRP-to-concrete single-lap joint shear test set-up and the main parameters varied are fibre type, fibre content and method of anchor construction. The behaviour as well as strength and failure of the test specimens are discussed and generic load–slip responses are provided which can form the framework for the future development of analytical models. Criterion with which to assess the optimal design of FRP anchors is also provided.

► Debonding failures of externally bonded FRP can be prevented or delayed with FRP anchors.
► Characterisation of shear strength and behaviour of FRP anchors via FRP-to-concrete joint tests.
► Optimisation of FRP anchor design based on confined of experimental program.
► Generic load-slip responses of anchored FRP-to-concrete joints are proposed.