Experimental Cyclic Evaluation of Exterior RC Beam‐Column Joints With Inadequate Beam Shear Resistance and Short Lap Splices in Columns: Comparison With Seismically Designed Joints

Beam‐column joints are responsible for transferring gravity and lateral loads among the main members of the structure. The failure of beam‐column joints may result in minor or total structure collapse during seismic events. The present study aimed to evaluate the existing weaknesses in buildings designed according to both new and old codes through an experimental program. The absence of transverse reinforcement in connection zones, inadequate lap splices of the column bars, and the failure to adhere to the spacing requirements of transverse bars in the plastic hinge formation area of major structural members included non‐seismic details considered in non‐seismic connections. To assess these weaknesses, four exterior connections, comprising one seismic specimen and three non‐seismic specimens, were evaluated under constant axial load and cyclic load with increasing amplitude. The results showed that due to the seismic details present in the seismic joint, a plastic hinge has formed at the end of the beam. However, the insufficient lap splice of the longitudinal column bars led to a greater concentration of damage of the non‐seismic joint compared to the seismic joint. The lack of transverse reinforcement in the joint area led to the formation of brittle shear failure in this area. Furthermore, the energy dissipated at a drift of 4.5%, and the average ductility factor of the non‐seismic detail specimen has decreased by approximately 43% and 39% compared to the seismic detail specimen, respectively.