Seismic strengthening of RC columns with straight FRP anchors

Abstract

The use of Externally Bonded Fiber Reinforced Polymer (EBR-FRP) systems is an established technique for the structural improvement of existing buildings but the technique features disadvantages. Premature FRP-to-concrete debonding has been commonly highlighted as one of the main problems, together with the difficulty of fully wrapping the structural element when the structure presents complex geometries. FRP straight anchors are used to transfer the forces from the FRP sheet into the structural element, ameliorating these two problems, but a comprehensive design method for FRP anchors has not yet been established despite the increased use and research attention given to FRP anchors. A research project was undertaken involving monotonically testing single-anchors in tension to investigate the behavior and capacity of isolated FRP anchors. However, a number of factors that may have a significant influence on the capacity of the anchors could not be investigated such as the behavior of the anchors when subjected to tension-compression cycles and the effect of dynamic loads. To address some of the aspects not covered within the single-anchor tests, six full-scale reinforced concrete columns were tested using pseudo-static loading, with the aim being to verify that the peak moment developed during testing was forecasted accurately.