Effects of column design variations on seismic performance of steel moment-resisting frames with fuse connections

• Seismic performance of steel moment frames with fuse connections is studied. • Archetype buildings of 2, 4, 6, and 8 stories are designed for comparative analysis. • The effect of column design variations on seismic performance is analyzed. • Various fuse failure models are explored to assess their effects on performance. Fuse connections featuring replaceable components that yield before beams or columns have been proposed for steel special moment-resisting frames (SMRFs) as low-damage connection concepts in seismic systems. While several are prequalified or under review for prequalification in the United States, the impact of column design requirements and fuse behavior on seismic performance has not yet been thoroughly investigated. This study analyzed typical steel SMRFs of varying heights (2, 4, 6, and 8 stories) using a prequalified yield-type fuse connection, specifically the Simpson Strong Tie™ (SST) Yield-Link (YL)® connection. Current prequalified design procedures for this connection allow columns to be designed for larger overstrength demands without meeting certain seismic compactness limits. This study investigates the impacts of column design variations (i.e., column overstrength, compactness, and capacity-limited forces) on collapse performance. Nonlinear static pushover and incremental dynamic analyses revealed that designs that considered seismic compactness, even with relaxed overstrength demands, outperformed those with higher overstrength but no compactness requirements, particularly in taller buildings. However, since the shallower column sections for shorter buildings were more likely to meet width-to-thickness limits for highly ductile members, relaxing overstrength requirements could reduce the collapse margin ratios in SST-YL SMRFs. These results indicate that there is potential to consider modified column design requirements for SST-YL connections, offering a cost-effective approach to improving structural resilience without compromising seismic collapse performance.