Classification of material and welding in fracture consideration of seismic steel frames

This paper shows a design method for preventing brittle fracture which was observed at beam-to-column connections in steel moment frames in Kobe at the event of the 1995 Hyogoken–Nanbu Earthquake. The proposed method is performance-based, in which qualities of structural steels and weldings are classified into 4 ranks, respectively, in accordance with the plastic deformation capacity of beams prior to the onset of brittle fracture. For determining and verifying the performance-based ranks of material and welding, recent experimental and analytical data are utilized which have been obtained through extensive research activities following the 1995 Earthquake.