Shear capacity of PVC-CFRP confined concrete column-RC beam interior joint strengthened with core steel tube

This paper presents an experimental investigation on polyvinyl chloride (PVC)-carbon fiber reinforced polymer (CFRP) confined concrete (PCCC) column-RC beam interior joint strengthened with core steel tube (CST). Thirteen interior joints are designed and tested under low cyclic loading considering the impacts of six variables, such as diameter-thickness ratio of CST, stirrup ratio of joint, axial compression ratio, CFRP strips spacing, reinforcement ratio of beam and reinforcement ratio of column. Distinct shear deformation in joint region finally dominates the failure of specimens. The load-displacement hysteretic curves are relatively full and eventually show inverse S shape, indicating the specimens have considerable seismic behavior and energy dissipation ca-pacity. The yield and peak shear capacities increase as diameter-thickness ratio, stirrup ratio of joint, rein-forcement ratio of column or reinforcement ratio of beam increases. Comparatively, the axial compression ratio and CFRP strips spacing exert less influence on shear capacity. Considering the impact of diameter-thickness ratio, stirrup ratio of joint and reinforcement ratio of column, a formula for estimating shear capacity of PCCC column-RC beam interior joints strengthened with CST is proposed and its accuracy is verified by test data.