<p>This study investigates the influence of gravity frames equipped with partial-strength flush end-plate beam-to-column connections on the seismic behavior of steel structures featuring special moment-resisting frames. For the connections, a two-bolted and a four-bolted flush end-plate configuration is considered where both are designed to be semi-rigid and partial-strength, to achieve ductile plasticity through end-plate yielding, thereby dissipating seismic energy and contributing to the seismic collapse capacity of the overall structural system without changing the collapse mechanism. In order to accurately implement the nonlinear behavior of the connections into the building models, finite element models of the connections are developed and cyclic loading procedure was applied to obtain the moment-rotation relationships of the connections. The numerical modelling methodology was validated against experimental data from the literature. The moment-rotation curves of the designed connections are then implemented into the structural model, with perimeter moment-resisting frames as its primary lateral force-resisting system. Three different structural models were investigated; a reference frame with conventional pinned beam-to-column connections and two frames utilizing two-bolted and four-bolted flush end-plate beam-to-column connections each. The structural models were analyzed through nonlinear static pushover analysis and incremental dynamic analysis. Seismic performance factors including static overstrength factor and period-based ductility were determined for comparison against the reference frame with pinned gravity connections. The base shear capacities and collapse fragility curves are investigated to further quantify system’s collapse safety margin. It was observed that the buildings utilizing flush end-plate beam-to-column connections achieve up to 30% increase in median collapse capacity, as well as significant increase in post yielding stiffness and base-shear strength.</p>