Development of a Mechanical Wedge-Barrel Anchor for CFRP Rods: Static and Fatigue Behaviors

In this study, a mechanical anchorage for prestressed carbon fiber-reinforced polymer (CFRP) rods was proposed. The proposed anchorage consisted of a steel barrel with a conical hole and three separate aluminum wedges that are in direct contact with the CFRP rod. The anchorage system relied only upon friction, without any adhesives required. The static and fatigue behaviors of the anchor were experimentally investigated according to the European guidelines for testing post-tensioning kits and fulfilled their requirements. The average tensile strength of the anchorage system for the 8-mm CFRP rods was 2,371.4 MPa, being greater than the guaranteed value of 2,047 MPa. The fatigue tests revealed that the wedge seating distance (prior to pulling the rod) significantly affected the occurrence of slippage between the anchor components. Therefore, a new displacement-controlled presetting system was developed to ensure adequate wedge seating distance. It eliminated the need for hydraulic jacks and demonstrated the capability of applying presetting forces greater than 110 kN. Furthermore, the anchors were tested under loading frequencies of 5, 17, and 23 Hz. The proposed anchorage was observed to be insensitive to the loading frequency because no slippage or temperature rise occurred under these loading frequencies.