Assess the Influence of the Through-Thickness Properties of Columns and Joint Geometry Upon the Behavior of Beam to Column Flange Welds 

Principle Investigator: Robert Dexter 
University of Minnesota (testing being performed at Lehigh University) 

    The through-thickness strength of rolled section flanges is not known, but the steel industry has indicated that the through-thickness properties are likely to vary considerably. This task is directed at determining the behavior of simulated moment frame connections which will not only determine the influence of column through-thickness strength upon the connection capacity but also the influence of joint geometry, weld heat input, and column stiffener size. 

    The task is made up of a series of tests on welded specimens in a "T-stub" configuration (both with pure tension and with prying). The steel materials, weld heat input, joint geometry, and column stiffener details will be varied to identify the influence of each of these variables on the performance of the welded joint. In almost all cases the material representing the beam flange will be of high strength steel so as to force the failure in the specimen to occur in the column flange. The following specific variables will be examined: 

- the influence of the stiffener size relative to the column dimensions 

- the size, type, and toughness of the stiffener welds 

- the influence of weld heat input (the range shall be between 40 and 70 kJ/in) 

- the influence of the backing bar upon weld performance: the influence of the continuous backing bar fillet weld and backing bar thicknes 

- the influence of root opening upon joint behavior 

The detailed breakdown of the technical activities in this task are provided in the workstatement available here.