Abstract: To reproduce typical disaster scenarios such as the September 11 attacks, this study conducted experimental and numerical investigations on the fire-induced progressive collapse resistance of steel frame beam-column subframes with top and seat double web angle connections following sudden middle-column removal. The experimental results indicated that, when the axial compressive force in the beam reached its peak, the displacement of the middle column entered a stage of rapid growth. After the beam-end bending moment reached its maximum value, the beam axial force changed from compression to tension, marking the transition of the dominant structural resistance mechanism from flexural action to catenary action. Based on experimental validation, an extensive parametric study was performed using the refined numerical model. The results indicate that increasing the axial restraint stiffness enhances the peak resistance of catenary action while reducing the corresponding critical temperature, with little influence on the onset temperature of catenary action. Increasing the load ratio further enhances the peak resistance of catenary action, but decreases both the corresponding critical temperature and the onset temperature of catenary action. In addition, increasing the height-span ratio not only improves the peak resistance of catenary action and its corresponding critical temperature, but also increases the onset temperature of catenary action. A comparison between the parametric results and the predictions from the Chinese standard GB 51249-2017 shows that the fire resistance limits calculated by the code are slightly higher than the numerical results, indicating a conservative design tendency. Moreover, the discrepancy remains within 10%, which is acceptable for engineering applications.