In the technical literature of structural and earthquake engineering, the phenomenon of progressive collapse is not directly incorporated into calculations; analysis, design processes, and many researchers consider this phenomenon as an additional load. Despite the importance of this issue in the seismic behavior of structures, design codes ignore the consideration of this phenomenon. Therefore, this paper analyzes the nonlinear behavior of a 4-story structure containing a special moment-resisting frame under progressive collapse loads. In this regard, three types of scenarios for the removal of corner, middle, and peripheral columns on the ground floor are considered, with 32 different column removal times including very rapid times and times close to the natural period of the structure applied to the studied model in the nonlinear OpenSees. The results indicate that as the column removal time increases, the maximum stress values in beams and columns, vertical displacement, beam rotation, and residual vertical displacement decrease. On the other hand, the difference in maximum displacement values at maximum and minimum times for scenarios1,2,and 3 is 81%,92%,and37% respectively, and for residual displacements, it is 61%,82%,and34%. Meanwhile, the difference in maximum rotations generated in the beam at maximum and minimum times for scenario 1 is nearly 5-times.