Effect of Joint Hoops on Seismic Behavior of Wide Beam- Column Joints

The effect of joint hoops on the seismic behavior and shear strength of wide beam-column connections under earthquake-type loading is investigated. Three full-scale exterior reinforced concrete wide beam-column joints, with inadequate joint shear strength according to ACI 318-14 and ACI 352R-02, were designed, constructed, and tested under reversed cyclic loading. Amount and spacing of joint hoops are the primary parameter and ratios of the reinforcement provided to that required by ACI codes were 1.71, 0.54, and 0. Test results showed that the joint without any hoop exhibited similar shear strength compared with others because spandrel beam helped resist the joint shear in the form of torsion. It is therefore suggested that the requirement of joint hoops in current codes of practice may be relaxed to reduce the reinforcement congestion in joint core without significantly affecting the performance of joints.