A nine-story moment resisting steel frame consisting of cold formed hollow section columns and hot Rolled H-beams, which is located at the central part of Kobe city and was constructed in 1989, suffered severe damage to many welded beam-to-column connections during the 1995 Hyogoken-Nanbu earthquake. In this paper, damage to beamto-column was detailed and plausible causes of the damage were discussed from the perspectives of materials, connection details, and seismic capacity demands. And also, the repair works for the damage executed to recover the original strength, is introduced.
