ASSESSMENT OF NON-LINEAR STATIC PROCEDURE FOR ALTERNATE PATH METHOD FOR DESIGNING REINFORCED CONCRETE STRUCTURES AGAINST PROGRESSIVE COLLAPSE

Abstract

Progressive collapse is a tragic partial or total failure of the existing structure, when a primary structural vertical element fails, the structure undergoes progressive collapse. Progressive collapse became a hot spot in many research areas after many terrorist events occurred in the twentieth century. In a chance to prevent or minimize such as those events, many codes added a part of design for progressive collapse resistance. ‘Unified Facilities Criteria’ (UFC) one of these codes including guidelines to assess the progressive collapse resistance. Alternate Path Method (APM) is the direct design approach of progressive collapse resistance defined in the UFC. In this thesis, a ten-story reinforced concrete structure subjected to gravity load and designed according to ACI-318-14 against progressive collapse following the non-linear static analysis for the APM approach was performed. According to the UFC guidelines, to assess the progressive collapse of any structure based on non-linear static analysis, the gravity load combination should be increased by Dynamic Increase Factor (DIF). DIF was found to be 1.07. All studied cases satisfied the UFC guidelines with safety factors equal to (3.31) and (3.03) for beams and slabs, respectively. A comparison between the nonlinear static and nonlinear dynamic analysis was carried out and it showed that, the non-linear static analysis gave a conservative solution with higher values of rotation compared to nonlinear dynamic analysis. Also it figured out that the maximum increase in beams and slab rotation is 53.0% due to column removal, and 74.0% due to internal wall removal.