Steel moment-resisting frames (MRFs) are well known for their ductile and stable hysteretic behaviour. For this reason, they are an attractive and effective structural system for seismic resistance. Current seismic design codes, namely Eurocode 8, provide system performance factors that should be used in the seismic design under different ductility classes. However, recent research studies have shown that the use of the code-prescribed performance factors lead to stiffer and heavier structural solutions that are not consistent with the performance-based design assumptions. A new methodology, Improved Force-Based Design (IFBD), has recently been proposed with the aim of a more rational determination of the adopted value of the behaviour factor, q, instead of using the upper bound reference values provided by the design code. This paper investigates if the obtained values of q for both EC8 and IFBD concerning steel MRFs are not only adequate, but also provide sufficient margins against collapse under maximum considered earthquake (MCE) ground motions. To this end, the methodology proposed in FEMA P695 was used. Additionally, the expected direct economic seismic losses are computed according to the PEER-PBEE methodology.
Modified capacity design rule for columns in tall steel MRFs with linear viscous dampers within the framework of Eurocode 8
