Three structural concrete interior beam-column joint units were tested. The beams were prestressed by tendons in the top and the bottom of the section but not at mid-depth. The columns were reinforced using Grade 380 longitudinal bars. Transverse shear reinforcement existed in all members and in the joint core. Static cyclic loading was applied to the units to simulate seismic loading. The presence of intermediate column bars was shown to significantly improve the shear capacity of the joint core, and the need for a relatively small neutral axis depth in the plastic hinge regions of beams for ductile behaviour was emphasized.