Cast Steel Replaceable Modular Links for Eccentrically Braced Frames

This paper presents an investigation into the use of cast steel replaceable links for eccentrically braced frames (EBFs). While conventional EBFs can be designed with a large response modification factor, and are thus very economical seismic-force-resisting systems (SFRS) in high-seismic regions, they can also be prone to damage states such as fracture at stiffener welds, local buckling, and lateral torsional buckling. They are also difficult to repair after an earthquake event since the EBF links are integrated into the floor beam of the seismic force-resisting frame. It is proposed that these drawbacks of conventional EBFs could be mitigated by using replaceable cast steel yielding links, since demand critical welds are avoided and damaged links can be replaced after an earthquake. Additionally, the cast steel EBF links are uncoupled from the beam sections and thus the most economical beam and link can both be specified. This paper presents sample building designs for a variety of building locations, using a newly developed cast steel EBF link concept that can be used to achieve more economical designs while also improving the performance of EBF frames.