Progressive Collapse analysis of Dual System “Special Moment Steel Frame with Special Concrete Shear Wall”

One of the approaches to passive defense is to protect important buildings against progressive collapse. Progressive collapse is a phenomenon that happens in a building due to the removal of some structural members. In this research, the progressive collapse of a 26 story residential building in Tehran was studied by the alternative load path (ALP) method according to UFC 4-023-03. Several independent column and shear wall removal scenarios were adopted from the first floor. Nonlinear dynamic analysis was performed with SAP2000 software according to UFC to evaluate the bridging ability of the building on the remained members. Plastic joints in beams and columns were defined in special moment frames according to the instructions ASCE41-17 and FEMA356. Also, the shear walls were modeled by the multi-layer shells method and the mid column equivalent method. The results showed that correct relocation of the shear walls in a dual system within building guidelines leads to appropriate resistance to progressive collapse.