Seismic damage, Brittle fracture, Strain concentration, Mechanical property Many steel frame structures in Kobe suffered severe damages during the Hyougoken-Nanbu Earthquake. Especially the large numbers of fracture were occurred at the welded beam-ends of beam-column connections. In this paper, on the 14 stories building we investigated, seismically damaged beam flanges of beam-column connections are analyzed to ascertain their fracture modes, strain concentration and mechanical property. Observation of the initial crack growth leading to brittle fracture, condition of strain concentration on the connections and comparison the base metal properties with the damaged metals nearby fracture section are discussed.
