Analyzing 150 experimental test data of interior beam-column joints, deformation capacity of beam-column joint subassemblage which failed in joint shear after beam flexural yielding was examined. Following findings were obtained : (1) The additional deformation due to slips of beam bars at the joint region should not be ignored in the evaluation of the overall subassemblage deformation at beam yielding. (2) Specimens failed in joint shear after beam yield did not show a rapid decrease of the strength in load-deformation curves. (3) The ductility ratio of subassemblage governed by joint shear failure after beam yielding was formulated as a function of the joint strength ratio [ c^τp^</τ>p : ratio of joint shear strength to joint shear input corresponding to beam flexural capacity ], joint shear reinforcement ratio [ P_w ] and the yield strength of beam bars [ σ_y ]. (4) Database study showed that the column axial stress levels, concrete strength and the bond property of.beam bars were not major influencing factors for the ductility ratio of the subassemblage failed in joint shear. (5) The proposed equation provides a good agreement between calculated and measured ductility of available 60 specimens, and it can predict the final failure modes of specimens with a good accuracy.
