ABSTRACT
Both the actual connection configurations of the moment resistant frames and local weld details are considered by means of advanced residual stress analysis techniques. Then, the effects of triaxial residual stress state on plastic deformation capacity are discussed based on finite element results on a wide-plate specimen loaded in tension. Finally, a series of fracture mechanics analyses were carried out to assess the effects of residual stresses and strength-mismatch on the fracture behavior. In addition, the current study also investigated several other factors that are commonly believed to affect the weld joint behavior, such as beam strength, weld discontinuity size, and backing plate. As a result, a great deal of insight has been obtained on the fracture behavior of the moment frame welds. Among other things, the results indicate that welding-induced residual stresses significantly increase fracture-driving force due to the presence of high tensile residual stresses. In the meantime, the high triaxial residual stress states identified in these joints can greatly reduce the plastic deformation capability, consequently promoting brittle fracture under dynamic loading conditions.
