Background to CSA-S16:24 provisions for seismic design and qualification tests on eccentrically braced frames with cast steel modular links

Steel casting technology has enabled the design and manufacture of seismic fuses with enhanced ductility and energy dissipation capacity. Recently, cast steel replaceable modular yielding links, also referred to as cast modular links (CML), were designed and experimentally validated for use in steel eccentrically braced frames (EBFs). To facilitate their application in practice, new provisions for design of EBFs with CMLs were proposed and adopted by CSA-S16:24. This paper presents these newly developed provisions, which are adopted in CSA-S16:24 along with the supporting technical background. Design guidelines and key response parameters of CMLs are discussed in detail. Guidelines for manufacturing and quality control of steel castings used as seismic fuses are provided. The new provisions require qualification testing of CMLs, whose guidelines are outlined. As an example, design of a four-storey EBF with CMLs is presented along with example qualification tests.