The behavior and load-deformation response of reinforced concrete exterior beam-column joints constructed with headed reinforcement is evaluated. The evaluation is based on the experimental results of two exterior joint specimens, one representative of construction for high seismic regions and one representative of construction for wind loads. An overview of the experimental study is presented prior to evaluating the effectiveness of the specimens constructed using headed reinforcement. Headed reinforcement lessens congestion in beam-column joints. Use of headed reinforcement eased specimen fabrication and concrete placement. Excellent behavior was observed for both specimens constructed to meet current ACI-ASCE Committee 352 design recommendations.

Disturbed strain regions are areas within a concrete member where plane sections do not remain plane after the member is deformed. Disturbed strain regions occur in portions of all reinforced concrete members. Typically, the disturbed regions are at the boundary regions, concentrated loading points, geometric discontinuities, and in members with relatively small span-to-depth ratios such as deep beams. Recently, more rational procedures have been developed for design of the disturbed regions of reinforced concrete, including strut-tie and compressive field procedures. Such design procedures combined with recent test results have indicated that the traditional design rules and guidelines are frequently unnecessarily conservative. This is particularly so where efficient reinforcing details are adopted such as the headed reinforcement discussed in this article.

Structural elements subject to high out-of-plane shear and those needing confinement for ductility in the post-elastic phase require concentrated transverse reinforcement. A T-headed bar has been developed that is inserted between the in-plane bars, then turned 90 degrees to lock behind them. Ease of placement makes these bars economical, and the ability of one T-headed bar to replace several conventional stirrups facilitates concrete placement and vibration.