Experimental assessment of the behaviour of bolted T-stub connections made up of welded plates

Abstract

The results of 32 tests on bolted T-stub connections made up of welded plates are presented and discussed. Although T-stubs have been used for many years to model the tension zone of bolted joints, the research was mainly concentrated on rolled profiles as T-stub elements. To extend this model to the case of welded plates as T-stub elements, a test programme was undertaken at the Delft University of Technology and is reported in this paper. It provides insight into the behaviour of this different type of assembly, in terms of resistance, stiffness, deformation capacity and failure modes, in particular. The key variables tested include the weld throat thickness, the size of the T-stub, the type and diameter of the bolts, the steel grade, the presence of transverse stiffeners and the T-stub orientation. The results show that the welding procedure is particularly important to ensure a ductile behaviour of the connection. Most of the T-stubs failed by tension fracture of the bolts after significant yielding of the flanges. However, some of the specimens have shown early damage of the plate material near the weld toe due to the effect of the welding consumable that induced premature cracking and reduced the overall deformation capacity. A solution to this problem is given by setting requirements to the weld metal to be used.