Recent developments on the Component Method

Abstract

The Component Method is well established and incorporated in Part 1.8 of Eurocode3 for the design of connections of steel frameworks. It is primarily intended to provide the elastic joint stiffness, although Part 1.8 includes provisions for also determining the inelastic moment-rotation response from the elastic limit to the ultimate moment. The latter provisions are empirical and use an established experimentally-based nonlinear equation to define the inelastic response. The Component Method has been further developed in recent years to determine the inelastic response using bi-linear springs with elastic and inelastic ranges. Procedures have also been developed at the University of Sydney to extend the Method into the post-ultimate range by defining tri-linear springs with elastic, inelastic and softening ranges. As well, recent research at the University of Sydney has produced a simple way to predict the moment-rotation response under fracture of components, thus enabling the Method to capture the full moment-rotation behaviour. The ability of the Method to predict full-range moment-rotation behaviour is especially useful for design by advanced analysis and progressive collapse analysis, as it allows both members and connections to be checked for stiffness and strength as part of the analysis. In parallel, an ongoing joint project between Sydney University and Tongji University on the strength of beam-to-upright connections in rack structures has extended to Component Method to cold-formed steel connections which include tang-connectors and bolts. The paper provides an overview of these recent developments of the Component Method, including the opportunity to incorporate the Method in a fully nonlinear procedure for the direct design of steel frameworks including connections by advanced analysis, also referred to as the Direct Design Method.