Probabilistic performance evaluation of steel moment resisting frame with masonry infill walls

This study presents a seismic fragility analysis of steel moment-resisting frames (SMRFs), with and without the inclusion of masonry infill walls (MIWs).Recognizing the often-overlooked structural contributions of MIWs, the analysis incorporates a detailed probabilistic seismic hazard analysis (PSHA) to generate tectonic-based ground motion sets for various hazard levels, considering dynamic properties of structures and site-specific characteristics.A 4-story SMRF building is designed and modeled in OpenSeesPy with and without MIWs.A total of 1,500 nonlinear time-history analyses (NLTHAs) are performed across 15 hazard levels, and structural demands are evaluated in terms of inter-story drift ratio (IDR).Fragility functions are developed for three performance levels.The results reveal that MIWs significantly reduce IDR with average reductions of up to 55%.Moreover, the inclusion of MIWs greatly improves fragility performance, lowering the probability of exceeding critical performance levels.