Cyclic Testing of Slab-Column Connections with Shear Reinforcement

The intent of this research program was to study the response of slab-column connections containing various types of shear reinforcement when subjected to combined gravity and cyclic lateral loading. The four test specimens were half-scale representations of interior slab-column connections in a prototype flat-plate building. The control specimen had no shear reinforcement, while the other specimens had closed-hoop stirrups, single-leg stirrups, and welded-head studs as shear reinforcement. The control specimen failed due to punching shear around the slab-column connection at 3.5% drift. None of the shear reinforcement specimens experienced punching failure during testing to 8% drift. The three types of slab shear reinforcement proved equally effective in resisting punching shear failure for these connections subjected to relatively low levels of gravity load. The presence of shear reinforcement significantly increased the lateral load ductility of the connection. The simplicity of placement of headed-stud reinforcement makes it an attractive alternative to single-leg and closed-hoop stirrups.