ABSTRACT
Recent experimental and analytical investigations by the authors (Iwashita et al. 2003) indicated that occurrences of brittle fractures from weld defects can be predicted rather accurately. Based on a series of numerical analyses, Iwashita et al. (2006) presented matrices showing the critical loads as a function of the size and location of weld defects and the material toughness. These investigations took into account the effects of a loss of plastic constraint at the crack tips. These effects are important because many of the weld defects in beam to column connections are small cracks although the material toughness is measured using a specimen with a deep notch. Crack tips of the weld defects show much greater fracture toughness than the material toughness determined by conventional testing procedures such as a single edge notched bend (SENB) test in which the notch root is under high plastic constraint (See Fig. 1).
