Fracture strength of a moment resisting welded connection under combined loading - Part I - Formulation

The problem of the welded connections fractured by the Northridge earthquak e has been addressed in the past in the context of the weld's performance. Whilst undeniably a great number of these connections failed due to the low fracture toughness of the weld material combined with substandard welding practice, the issues of the column's material properties and their effect o n the connection's integrity has not yet been tackled. As a direct result o f this observation, the present paper sets out to determine the stress inte nsity factors for a column which contains in its flange a semi-elliptical s urface crack. The present treatment becomes all the more important in the l ight of current North American practice which in some cases adopts reinforc ing fillet welding which is known to introduce crack-like defects. In a com panion paper, the results of this formulation are used to explore the colum n's resistance to fracture. (C) 2000 Elsevier Science Ltd. All rights reser ved.