Behavior of external reinforced concrete beam to column connections subjected to earthquake type loading

Twelve full-size exterior beam-to-column subassemblies were constructed and tested. The primary variables studied were: (1) ratio of the sum of the flexural strengths of the columns to that of the beam; (2) amount of transverse reinforcement placed within the joint; (3) shear stress in the joint; and (4) inclusion of transverse beams and slab for half of the specimens. In all bare specimens, diagonal cracks connecting the opposite corners of the joint were observed during the first cycle of loading. In specimens with transverse beam and slab, the flexural cracks formed when the slab reinforcement was in tension did not close completely with the reversal of the loading direction. Conclusions stress the importance of: (1) increasing both the flexural strength and transverse reinforcement ratios; (2) reducing joint shear stress; and (3) including transverse beams and slab.