Carbon Fiber-Reinforced Polymer Spike Anchor Design Recommendations

The simple detailing-based design recommendations for carbon fiber-reinforced polymer (CFRP) anchors presented herein were developed based on a database of 51 small-scale tests. The small-scale database indicated that a single CFRP anchor can develop the fracture strength of two layers of 10 in. (254 mm) wide CFRP strips if the anchor is properly detailed. Although CFRP strips are currently being designed for a maximum effective strain of 0.004, CFRP anchors should be designed to resist the full tensile capacity of the CFRP strips since the crack width distribution in a member can produce CFRP strains that exceed the maximum permitted effective strain. To achieve full CFRP material use, data shows that an anchor-to-strip material ratio (AMR) greater than 2.0 should be used. Additionally, the anchor holes should have a minimum chamfer radius that is 1.4 times the anchor hole radius to mitigate stress concentrations at the anchor bend.