Proposed Design Guidelines for EBFs Designed with Cast Steel Replaceable Modular Yielding Links

Cast steel replaceable modular yielding links (CMLs) were previously proposed for use in eccentrically braced frames (EBFs) and their performance was recently experimentally validated in a large experimental program at the University of Toronto. Selected results from the experiments are presented in terms of the link hysteretic response, the link axial response throughout the experiments, and key response parameters characterized in the experimental program. Using findings from the experimental program, a set of guidelines are provided for: (1) General design requirements, (2) fabrication and quality controls on CMLs, (3) determining the key response parameters of CMLs, (4) performing qualification tests on CMLs, and (5) designing EBFs with CMLs. The proposed guidelines have been adopted by the Canadian Steel Code CSA-S16:24. This paper provides a summary of the proposed design guidelines and some of the background behind these guidelines. Simplified equations are presented for determining the key response parameters of CMLs such as link stiffness, link yield shear, link plastic shear, etc., which can be used in the design.