Finite-element fracture analyses of welded beam-column connections

Unexpected brittle cracking of welded beam-column connections during the 1994 Northridge earthquake has raised serious concerns about standards and practice for the seismic design and construction of steel moment resisting frames. As part of a nationally coordinated program to investigate the connection damage, finite-element fracture analyses are used to quantify fracture toughness demands in welded beam-column connections as influenced by various detailing parameters. Toughness demands at weld root defects in the beam flange groove welds are quantified in terms of K-I, CTOD, and CTOA. Summarized are insights concerning the role of finite-element fracture analyses to investigate fracture behavior and the influence of factors such as flaw sizes, weld strengths, inelastic crack growth, and other parameters affecting fracture toughness demands.