Exterior RC wide beam-column connections: Effect of beam width ratio on seismic behaviour

Design recommendations stipulated in international standards for seismic design of reinforced concrete (RC) wide beam-column connections are based on limited experimental studies. To supplement the existing information, an experimental study was conducted that focused on the effect of beam width to column width ratio (or beam width ratio) on the seismic behaviour of exterior beam-column connections. Four specimens were designed, constructed and tested under reversed cyclic loading conditions. The primary test variables were the beam width ratio and the joint shear stress ratio (γd). The specimens were designed in conformance with ACI 318-14 and ACI 352R-02. They had beam width ratios of 1, 1.5, 2 and 2.5 and γd, of 0.74, 1.12, 1.63, and 2.03. According to ACI 352R-02, the γd value should be lower than γn = 1.25 for joints confined on three faces. The results indicated that specimens with beam width ratios of 1 and 1.5 and γd of 0.74 and 1.12 were capable of supporting the complete formation of beam plastic hinges with no major cracks in the joint region. In contrast, specimens with beam width ratios of 2 and 2.5 and γd of 1.63 and 2.03 exhibited significant damage at the joint core. Torsional failure of the spandrel beam was also observed in specimen with beam width ratio of 2.5.