Short‐length mechanical bond anchorage for reinforcement bars made of FRP: Experimental and numerical investigations

Abstract

The availability of fiber‐reinforced polymers (FRP) as an alternative for conventional steel reinforcement in concrete construction is increasing. To widen the scope of application, for example, in the case of prestressing, and to improve the bond behavior at the bar ends, end anchorages need to be considered. Within this paper, a new short‐length anchor representing a combination between a bond and mechanical anchor is presented using a special inner geometry to increase the load‐bearing capacity due to the mechanical wedge effect, with a bonding length of only 50 mm. Besides giving a short overview of different anchorage systems, the paper focuses on experimental investigations that were performed with mechanical bond anchors with a variation of the inner geometry of the steel anchorage, different FRP bars, and different load transfer media. A numerical investigation completes the study by showing an approach to calculate the presented mechanical bond anchors. It was found that a small thickness of the bonding material is favorable, and a decrease of the bonding length is not necessarily disadvantageous. A tensile failure of the FRP bars was not achieved, although a full exploitation seems promising since a utilization of up to 83% of a basalt FRP bar was reached.