Seismic Rehabilitation of Welded Steel Beam-to-Box Column Connections Utilizing Internal Flange Stiffeners

This work investigates the seismic performance of rehabilitated steel moment connections using internal flange stiffeners (IFSs) welded to the face of a built-up box column and a beam flange inner side. The objective is to provide a rehabilitation scheme that excludes interference from the composite slab and story height limitation in an existing steel building. Five rehabilitated moment connections with different IFSs were tested according to AISC (2005) loading protocol to validate their cyclic performance. Two rehabilitated moment connections had excellent performance; no welded joint fractures were found in the connections with a drift in excess of 4%. The specimens were modeled using the computer program ABAQUS to further verify the effectiveness of the IFSs in transferring beam moments to a column and to investigate potential sources of connection failure. Design guidelines for the rehabilitation scheme are provided based on test and analytical results. [DOI: 10.1193/1.3480275]