Abstract:
This study discusses an experimental program carried out for evaluating the behavior of reinforced concrete (RC) wide concealed-beam-narrow-column joints when subjected to lateral earthquake loading. The first part of the study focuses on as-built joints, designed and constructed without taking earthquake loads into account. The second part of the study concentrates on the seismic performance of the same joints tested in the first part, except that the reinforcement details are improved in part in accordance with ACI 318-08 provisions for earthquake-resistant structures. Four full-scale interior and exterior beam-column subassemblages were tested under quasi-static cyclic lateral loads. The joints satisfied some of the ACI 318-08 design and steel detailing requirements but still violated the dimension limitations specified in the same code or recommended by ACI 352R-02. All joint specimens developed considerably improved seismic performance, manifested by preventing or delaying joint shear failure, higher lateral load capacities, lower stiffness degradation, larger energy dissipation capacities, and a stable overall hysteretic response when compared with the as-built joints. Copyright © 2013 American Concrete Institute.