Performance-based assessment of steel structural systems under blast loading using incremental dynamic analysis

Blast-resistant design of steel structures requires a clear understanding of system-level response under extreme demands. Traditional approaches lack quantitative performance criteria across different lateral load-resisting systems. This study investigates two- and five-story moment-resisting frames (MRF), concentrically braced frames (CBF), and dual MRF-SPSW systems under blast loading at 5 m and 10 m standoff distances. Incremental Dynamic Analysis (IDA) was employed, with interstory drift ratio and von Mises stress as performance indicators. The numerical model was validated against scaled experimental tests, showing less than 5% deviation in stiffness and strength. MRFs exhibited the most favorable performance, with significantly lower drift demands and higher collapse prevention (CP) capacities. CBFs showed intermediate performance, while SPSWs, despite their high initial stiffness, experienced concentrated damage and amplified upper-story drifts. Increasing standoff distance enhanced resilience, tripling the blast capacity of MRFs. The findings establish drift-based performance benchmarks and highlight system-specific vulnerabilities, offering practical guidance for performance-based blast-resistant design.