Ductility requirements for the design of bolted shear connections

Abstract

The resistance of shear bolted connections is traditionally evaluated by considering an equal distribution of internal forces amongst the bolts. In fact, such an assumption may only be seen as the result of a plastic redistribution of the internal forces, what requires shear ductility in the vicinity of the bolts. In the present paper, ductility requirements are proposed. They have been derived by the first author during a two-years stay at Liège University. For more details about this work; the interested reader is requested to refer to the Henriques thesis [5]. SHEAR BOLTED CONNECTIONS A connection can be classified as Shear Bolted Connection when the forces transferred between the elements induce pure shear in the bolts. Two types of shear connections, also called lap connections, may be found: single and double overlap connections. The difference consists in the number of shear planes that cross the bolt shanks. In Shear Bolted Connections, two different elements may be distinguished: connectors (bolts) and connected elements (plates). The term plate is used to refer to column flanges, beam flanges, beam webs, splice plates, etc. When a bolted connection is submitted to shear, forces are transferred from one plate to the other (others) by plate-to-bolt contact. Neglecting the small friction developed between plates and negligible bending of the bolt, four different resistance and deformation modes should be considered: Bearing of the plate and/or bolt; Shear in the plates; Tension in the plates; Shear in the bolt shanks. From these, the behaviour of a shear bolted connection can be defined by the response of two different parts: bolt zone, where bearing and shear forces develop; and the plate between holes where direct forces develop in the plate. The work presented in this article focuses on the bolt zone; so the failure of the connection by excess of tension in the connected pates is here not considered.