Evaluation of the Vertical Vibration Period Uue to Column Elimination and Its Effects on Structural Response Due to Progressive Collapse

Progressive Collapse is a phenomenon in which a large part of a structure is destroyed by a small damage. In recent years، many codes and researches have investigated the behavior of structures against progressive collapse and proposed methods to evaluates the structural responses. One of the methods for estimation of structural response is alternative load path method using linear static، nonlinear static and nonlinear dynamic analysis. Nonlinear dynamic analysis is used to achieve more accurate responses. Since that، duration removed columns in the nonlinear dynamic analysis has a significant impact on the structural response، the purpose of this paper is to evaluate the effect of structural response due to duration removed columns. For this purpose، some ordinary buildings was selected and their reponses was evaluated against column elimination''s time and critical conditions was determined. Since that، in design codes، column elimination''s time، depends on the vertical period of the bays above the removed column، a proposed method is presented for determination this time.