Investigation of Effect of Different Lateral Load Resisting Systems on Seismic Progressive Collapse of Steel-Moment Frames at Different Scenarios

Seismic progressive failure refers to the early fracture of some key structural elements during an earthquake due to explosions or design and construction defects. It results in the elimination of these elements from the structural frame, leading to a rise in stress in the adjacent elements followed by large-scale failure in part of the structure. The study of this phenomenon is of utmost importance and constitutes the topic of this research. So, the present research evaluated seismic progressive failure potential in steel frames with various structural systems. In the present study, the 3-story steel frame was modeled by non-linear beam-column elements with wide plastic, which are available in the archive of Apensis software. Then the models were subjected to nonlinear dynamic analysis and the results related to earthquake stimulation and progressive failure in Excel and MATLAB software were examined and compared in the form of graphs and numbers. The structural systems considered in this study were flexural, cross braced, eccentrically braced, and knee braced frames. In order to examine the seismic progressive failure potential, the El Centro, San Fernando, and Kobe accelerograms were selected, and two scenarios, namely the elimination of the side and middle columns at the first level were considered. According to the results, elimination of the side column resulted in larger responses since only one beam contained the upper node of the eliminated column.Moreover,frames with a larger number of levels were less affected by column elimination.