Through-Thickness Properties of Column Flanges in Welded Moment Connections

Abstract

Forty tee-joint specimens were tested to assure that through-thickness strength or ductility of the column flanges is not a potential failure mode for welded moment connections. The specimens were designed with 690-MPa yield-strength pull plates and a high-strength high-toughness double groove shop weld (not representative of structural welds) to attempt to induce through-thickness failures in column flanges. Despite high strain rate, high-heat input welds, and several details designed to trigger fractures, only one through-thickness failure occurred. In most cases the pull plates broke, and in all cases the stress levels exceeded 690 MPa, well above the stress level that could be delivered by structural steel beam flanges. The only specimen fabricated without continuity plates resulted in a through-thickness brittle fracture of the column flange, although the nominal pull-plate stress was quite high (698 MPa). The lack of yielding in the through-thickness direction can be explained by the existence of triaxial constraint of the column flange material.