Influence of Anchor Size on Anchored CFRP Systems

Abstract

This study investigated carbon fiber–reinforced polymer (CFRP) spike anchor parameters that govern their effectiveness in developing the full strength of CFRP strips, including any size effects that may exist in anchored CFRP systems. Twelve tests were conducted on concrete beams reinforced in flexure with anchored CFRP strips up to 25.4 cm (10 in.) wide. The primary parameters investigated were width of CFRP strip, number of layers of fabric in CFRP strip, number of anchors per strip width, ratio of anchor to strip cross section, anchor fan overlap length, and chamfer radius of the anchor hole. The full distribution of strains at the surface of the anchored CFRP strips was monitored using an optical measurement system. These measurements helped evaluate the effectiveness of various anchor details in distributing strains across strips. The experimental program confirmed size effects in anchored CFRP systems. The larger the CFRP strip area developed per anchor, the lower was the stress at fracture of that strip. In addition, the anchor-hole chamfer radius was found to influence both anchor strength and the strain distribution in CFRP strips.