Post-limit stiffness and ductility of end-plate beam-to-column steel joints

A procedure for the evaluation of ductility in steel joints is presented. Using the component method as background, a non-linear analysis for a number of end-plate beam-to-column joints is performed that is capable of identifying the “yield” sequence of the various components and the failure of the joint. Each component is characterised using a bi-linear approximation for the force–displacement relation. Comparing these results with the corresponding experimental results leads to a proposal of the post-limit stiffness of the various components. A component ductility index is proposed for each component as a means of classification with respect to ductility, using the three ductility classes currently proposed in the literature. A joint ductility index is also proposed, which can be used to verify available rotation against the structure required rotation.