A Design Method for the Tension Side of Statically Loaded, Bolted Beam-to-Column Connections

In this paper a design method for the tension side of statically loaded, bolted beam-to-column connections is developed based on the plastic behaviour of the flanges and the bolts under the assumption that the plastification is large enough to allow the adoption of the most favourable static equilibrium. Until now bolted beam-to-column connections without stiffening plates welded between the column flanges have been generally avoided. The reason for this is that the deformations of the connection are considerable and, until now, a formula which allows the determination of the stiffness and strength of a column flange has been lacking. This paper presents the derivation of an "effective" length formula for a column flange in tension without stiffening plates between the flanges. The derivation is based on the analysis of two different collapse mechanisms. One mechanism occurs if bolt failure governs collapse. The other mechanism corresponds to collapse resulting from the full plastification of the column flanges. Tests are discussed that were performed to insure that the developed design rules would lead to connections that would satisfy the limit state of deformations as given in the Dutch regulations for constructional steel work (for both) serviceability and ultimate limit states