Impacts of configurations on the strength of FRP anchors

The usage of FRP anchors to prevent FRP strips from premature debonding failure is gaining acceptance in strengthening applications of concrete members. FRP anchors can fully develop the strength of FRP strips when they are properly designed. However, existing equations do not well include the comprehensive impact of the spike embedment depth, the bend ratio, the strength ratio of FRP anchor to FRP strip and the dowel angle on the anchor strength. Based on 64 tests failed in anchor rupture, this study proposes a comprehensive equation to determine the anchor strength. Comparisons between equation based predictions and 12 experimental results indicate the advantage of the proposed equation against existing equations. Then, the study propose a feasible technique, i.e. the bidirectional FRP patch, to improve the efficiency of current FRP anchors. Compared with equation based predictions for those FRP anchors without FRP patches, experimental results obtained from 20 specimens with FRP patches indicate significant increases on the anchor strength. This observation favors the usage of FRP patches to improve the efficiency of FRP anchors.