Investigation of progressive rupture due to removal of gravity bearing members in ۱۵-story steel frame

Abstract Objective and Method: In recent years, with the publication of Section ۲۱ and also the addition of the Explosive Loads section to Section ۶, the importance of investigating the effect of explosions on different parts of the structure became clearer. Therefore, due to the importance of this issue, in the present study, the progressive rupture due to the failure of gravity bearing members in EBF braced steel frames was investigated. SAP۲۰۰۰ software was used for modeling. Results: The results showed that the structures designed against earthquakes do not necessarily have sufficient resistance to progressive failure. According to the results in all models studied in this dissertation, ۵, ۱۰ and ۱۵ story buildings with dual system of steel bending frame and eccentric bracing are examined in terms of progressive rupture. In the case of elimination of the middle column in the upper floors of the structure, the performance levels of the plastic joints were within the permissible limits of the UFC regulations; In other words, in these removal cases, damage to the structure will not occur. But in the side frame without bracing, removing the side column on the upper floor will cause damage to the structure (see the results for the last floor of all models). According to these explanations, by changing the location of the brace in the upper floors of the middle openings and placing the braces in the side openings, the percentage of probability of failure can be reduced.

Keywords:

_Braced steel frames , Progressive rupture , Design methods , Removal modes