Abstract: With the aid of a validated high-fidelity composite floor model, a reduced-order finite element model of steel-framed structures with composite slabs was established for analyzing the structural behavior under progressive collapse scenarios. The accuracy of the reduced-order model was validated by comparing it with a composite floor substructure test. The progressive collapse resistance of a five-story prototype building was analyzed using the reduced-order model. The analysis results indicate the prototype building has sufficient loading-carrying capacity to prevent the progressive collapse caused by the failure of a single ground floor column. Except for the corner loss scenario, the altering of floor number has an insignificant effect on the progressive collapse behavior of the prototype building. The predicted progressive collapse resistance of the prototype building is improved by 114% after considering the contribution of the composite slab.