An experimental and numerical study on behaviour of reinforced concrete corner beam-column joint

An experimental and numerical study studied performance of reinforced concrete (RC) corner beam-column connection (BCC) subjected to cyclic loading. Each BCC consisted of upper, lower column and two beams: one of them was free end (A) while the other was fixed end (B). The cyclic loading was applied on the end of beam (A) while the beam (B) was unloaded and subjected to torsion stresses due to fixation. Two parameters were studied: one of them experimentally and the other numerically. The first was amount of shear reinforcement inside the joint, and this variable was experimentally investigated by three BBCs. The second was eccentricity of beam (A) with respect to the column edge either inside or outside. This parameter was numerically studied using finite element analysis. All BCCs were tested under reversible 14 cycles. The vertical displacement at the free end of beam (A), cracks, failure mode, crack and ultimate loads were observed in details at each cycle. The results showed that the failure of the specimens that shifted outside the column edge was occurred at the connection between the unloaded beam (B) and the column face. Additionally, the capacity of BBC decreased when the loaded beam (A) has main bars extended outside the column core. The ultimate load of the specimen, which had beam (A) with 25 mm shift outside the column core, was 24% smaller than that of the specimen without shift. As the shift of beam (A) increased, the deflection increased at the same level of the load. The results proved that the increase in amount of the stirrups inside the joint transmitted the main failure into the column faraway the joint. BCC strength improved with increasing of the shift of the loaded beam inside the column until the loaded beam axis located with the column axis; then, the capacity of BCC decreased.