Response of Cyclically Loaded Extended End-Plate Moment Connections When Used With Welded Built-Up Sections

An experimental investigation was conducted to study the behavior of extended end-plate moment connections subjected to cyclic loading. Eleven specimens were tested, representing typical connection configurations used in the metal building manufacturing industry. Four of the beams were shallow (30 in. or less), and seven were deep (60 in. or more). Two of the beams had compact webs, two had non-compact webs, and seven had slender webs. All specimens were designed according to the "thick plate" procedure contained in AISC Design Guide 16, Flush and Extended Multiple-Row Moment End-Plate Connections. A displacement-controlled history was used to load the specimens. Experimental maximum moments were compared to analytical predictions of beam and connection strength. Also, each moment versus rotation relationship was analyzed for compliance with the requirements of Ordinary, Intermediate, and Special Moment Frames, as defined by AISC in the Seismic Provisions for Structural Steel Buildings.

The experimental results demonstrated that the thick plate procedure in Design Guide 16 is an accurate model for predicting the strength of the connection elements, and the procedure is recommended for designing connections subject to cyclic (seismic) loads. The connection design moment should be based on the expected plastic strength of the beam, regardless of the equations governing nominal beam strength.