Effectiveness of FRP bar anchors for prestressed concrete members

Prestressed concrete members are widely used around the world to realize different types of structure, including bridges and skyscrapers. Steel strands are generally employed to apply a compression force into the concrete. Recently, fiber-reinforced polymer (FRP) composite bars have been considered for replacing traditional steel strands in specific applications. The main advantage of FRP bars is their resistance to corrosion. Furthermore, they may have a higher tensile strength-to-weight ratio and fatigue resistance compared to steel strands. Although using prestressed FRP bars may entail for advantages over traditional steel solutions, the anchorage system is an open issue for this technology. Indeed, the anchorage should guarantee a high level of tensile stress into the bar and, at the same time, avoid local failures. In this paper, the preliminary results of an experimental campaign comprising tensile tests of glass and carbon FRP bars with different anchors are provided and discussed. The experimental campaign was aimed at investigating the effectiveness of newly developed wedges in properly anchoring the composite bars. Tensile test results and modes of failure are discussed, shedding light on the main parameters that affect the mechanical behavior of the bars considered.