Tensile Behavior of Large Diameter Carbon Fiber Anchors

Abstract

The use of carbon fiber (CF) anchors is becoming more common in structural retrofit applications. Typically, CF anchors are used to prevent or delay debonding of fiber-reinforced polymer (FRP) laminates from concrete substrates, as in flexural strengthening applications. For seismic repair of reinforced concrete (RC) circular bridge columns, the role of CF anchors is typically to transfer large tensile forces from the column to adjoining members such as a footing or cap beam. Thus, the required CF anchor diameter should be large enough to resist the demand. The research presented in this paper focuses on the tensile behavior of 25 mm-diameter CF anchors to investigate the potential of large diameter CF anchors for seismic repair of RC circular bridge columns. To that end, the behavior of large diameter CF anchors was experimentally investigated through a number of pull tests to identify the impact of fan angle on the tensile rupture capacity. A unique test setup was designed and manufactured to test large diameter CF anchors. Based on the results of this study on commercially available 25 mm-diameter CF anchors, a 530 mm long fan with fan angle between 37 to 57 degrees is recommended with a dowel embedment depth of 380 mm When the anchor fan is well-confined with a transverse CFRP wrap a tensile capacity of 250 kN is achievable.