Seismic improvement of RC beam–column joints using hexagonal CFRP bars combined with CFRP sheets

Under severe earthquake conditions, the lack of strength and ductility in reinforced concrete beam–column joints with non-seismic details raises serious concerns for overall structural safety. In this study, experimental research was carried out in order to try and improve the seismic strength and performance of reinforced concrete exterior beam–column joints by applying embedded carbon fiber-reinforced polymer (CFRP) bars combined with CFRP sheets. CFRP bars have a flat-typed hexagonal cross-section. Specimens of reinforced concrete exterior beam–column joints were manufactured based on a newly developed strengthening method by applying embedded CFRP hexagonal bars combined with externally bonded CFRP sheets, and tested for comparison with the specimen of a conventional reinforced concrete exterior beam–column joint. The newly developed design approach could minimize damage and improve the overall structural performances of beam–column joints under cyclic load reversals.