Comparative study on the performance of non-seismically designed beam–column joint reinforced with ribbed CFRP bars using various anchorage methods

Enhanced structural performance can be achieved by applying CFRP bars to T-shaped beam–column joints, provided that appropriate anchorage is ensured. This study investigated the structural behavior of T-shaped beam–column joint reinforced with CFRP bars as the primary longitudinal reinforcement, focusing on different anchorage techniques such as lap splices, mechanical couplers, epoxy-filled steel pipes, and expanded ribs (with one, two, or three ribs). A total of six specimens were fabricated and subjected to monotonic transverse loading. Key performance indicators—including load–deflection behavior, failure modes, strain distribution, and ductility—were evaluated. Additionally, the joint shear strength obtained from the tests was compared with predictions from established design guidelines. Among the anchorage methods, specimens using expanded ribs showed approximately 15.2–185 % higher load resistance and 4.7–394 % greater energy dissipation capacity than those with hybrid connections. The configuration with two expanded ribs exhibited the highest ultimate load, outperforming the one- and three-rib specimens by approximately 24.2–34.7 %. Except for the specimens with mechanical couplers and epoxy-filled steel pipes, failure occurred in the joint region, where the strain in the CFRP bars reached approximately 4008 µε. Since both the ASCE and AIJ equations overestimate the shear strength of beam–column joints reinforced with CFRP bars, the shear strength parameter k in the ASCE equation was modified to 0.4. • The structural performance of T-shaped beam–column joints reinforced with CFRP bars was investigated. • CFRP bars with expanded ribs were compared to hybrid reinforcement with steel bars. • The experimental joint shear strengths were evaluated against predictions from existing design codes.