Failure mode identification of reinforced concrete coupling beams

This paper presents a new approach to identify the ultimate failure state of reinforced concrete (rc) coupling beams subjected to lateral loadings. the proposed approach is based on simple geometric properties and reinforcement detailing of the coupling beam. a simple threshold expressed in terms of aspect ratio and main reinforcement to transverse reinforcement ratio is established to evaluate whether the ultimate failure state that would evolve during earthquake ground shaking in conventionally reinforced rc coupling beams is brittle or ductile. another threshold stated in terms of main reinforcement to transverse reinforcement ratio and sloped reinforcement to transverse reinforcement ratio is recognized to evaluate whether the ultimate failure mode in the rc coupling beam with sloped reinforcement is brittle or due to sloped bar buckling during earthquake shaking. brittle failure mode (shear failure) and sloped bar buckling should be avoided in design and mitigated in existing structures. results from this proposed approach are compared with those obtained for twenty seven laboratory specimens tested by other researchers. © 2017 just. all rights reserved.