Unified classification system for beam-to-column connections

A new classification system for beam-to-column connections is proposed, in which the stiffness and strength characteristics of the connections are considered simultaneously. Using this method, it follows that a connection is classified into a unique category, thereby clarifying the position for design engineers. Since connection stiffness and strength are considered simultaneously, new terms have been proposed for defining the connection categories; these are: fully-connected, partially-connected, pin-connected and non-structural. Compared with the properties of the connected beam as well as the adjoining columns, a fully-connected connection should have high strength and high stiffness; a partially-connected connection has moderate strength and stiffness, a pin-connected connection has either low stiffness or low strength and non-structural connections are those that cannot meet either the strength or the stiffness or the ductility requirements for the other three types of connections. Numerical examples have been included which demonstrate the validity of this classification system. Its basis is that the overall performance of the frame at both the serviceability and ultimate limit states should closely accord with that predicted by the associated method of analysis; this is particularly important when either of the standard approaches assuming pinned or rigid connections is used.