Practical Ideas for the Design Professional by Duane K. Miller, Sc.D., P.E.
The traditional approach used to design a fillet weld assumes that the load is resisted by the weld’s throat, regardless of the direction of loading. Experience and experimentation, however, have shown that fillet welds loaded perpendicular to their longitudinal axis have an ultimate strength that is approximately 50% greater than the same weld loaded parallel to the longitudinal axis. The traditional approach, in which direction of loading is not considered, is therefore conservative. Such a philosophy was incorporated into the AWS D1.1 Structural Welding Code - Steel, as represented by the following provision from the 1994 edition.