Progressive collapse-resisting capacity of steel moment frames considering panel zone deformation

Panel zone deformation is known to be a major parameter affecting the nonlinear behaviour of moment resisting steel frames subjected to earthquake loads, especially in weak column-strong beam conditions. In this study, the reinforcing effect of the panel zone on the progressive collapse and the capacity of moment resisting steel frames was investigated with the aid of nonlinear dynamic analysis. Both gravity load-resisting system structures with weak panel zones and lateral load-resisting system structures with strong panel zones were studied. The analysis results show that the panel zone deformation is highly dependent on the location of removed columns. The panel zone deformation turns out to be very significant when a column adjacent to an exterior panel zone is removed. On the other hand, the panel zone effect is not significant if a column adjacent to an interior panel zone is removed. As the number of stories increases, the effect of a weak panel zone on the overall behaviour decreases regardless of the panel zone strength and the location of any column removed.