Seismic Behavior of Steel Retrofitted Moment Connections with Stiffeners Inside Beam Flange
This research describes the seismic performance for the rehabilitation of steel moment connections welding stiffeners between the face of the column and inner side of the beam flange. Nine large-scale moment connection specimens with a welded box column and steel beam were tested. A moment connection with bolted web-welded flange details was tested and use as a benchmark for the rehabilitated scheme. Eight rehabilitated moment connections with different sizes of stiffeners were tested to validate the performance. Five of eight rehabilitated moment connections showed excellent performance under the AISC seismic loads in excess of 4% drift, with minor strength degradation and no fracture of the welded joint. However, three rehabilitated moment connections failed as the un-rehabilitated moment connection due to insufficient stiffener stiffness and strength. The connection specimens were also modeled using the non-linear finite element computer program ABAQUS to further confirm the effectiveness of the stiffener in transferring beam moment to the column and to study potential sources of connection failure. A design guideline for the rehabilitating scheme was provided based on the tests and analyses conducted in this study.
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