3D simulation of bolted connections to unstiffened columns—II. Extended endplate connections

Abstract

Traditionally column web stiffeners are used to increase the load carrying capacity and rigidity of extended endplate, bolted, moment connections in structural steelwork. However, elimination of these stiffeners in such connections is favored because of significant fabrication economy and simplification of connection details. Besides, the optimum analysis and design of the frame may demand joint moments other than the full plastic capacity of connecting members making column stiffening unnecessary. In this context, the principal bending planes of the column flange and endplate are orthogonal and, thus, only a three-dimensional (3D) model can address connection behavior. For this reason, there are only a limited number of experimental and analytical reports concerning this phenomenon. A description and application of such a model, using inelastic finite elements, has already been provided in Part I, a companion paper (Journal of Constructional Steel Research, 1996, 40, 169–187), in which deformation and prying action are studied for T-stub connections. This paper presents the structural properties, both stiffness and strength, of an extended endplate connected to an unstiffened column flange using high strength prestressed bolts. The case studies considered in the current paper offer more insight into the significance of endplate and column flange interaction; besides the displacement and stress distributions, the prying phenomenon, both as to value and distribution, is also discussed. ANSYS, version 4.4, a large-scale general purpose finite element code is selected for the analysis.