The Evaluation of Progressive Collapse in the Space-Structure with the Scenario of Simultaneous Removal of a Column and Brace (Case Study: Wind Tunnel Retaining Structure)

Progressive collapse is defined as the propagation of some primary local failure from one member to another that eventually leads to the failure of the entire structure or a large part of it. Potential hazards or incidents that can result in progressive damage include fire, collision, explosion, and earthquake. In the mechanism of progressive collapse, a local failure, such as the major damage or removal of a column, causes a total and significant collapse that will lead to the collapse of the entire structure. The aim of the present study is to investigate the progressive collapse in a special braced wind tunnel retaining structure with the scenario of simultaneously removing one of the main columns and bracings in the base level. In this study, a wind tunnel retaining space structure that supports the main structure of the wind tunnel is considered. This high-rise steel structure is braced with a composite structural system, which incorporates various failure scenarios. The models are first analyzed and designed in ETABS software and their output is transferred in SAP2000 software and then nonlinear static analysis is performed on those models. The results show that in case of the removal of bracing in the event of an explosion, only in members close to the removed elements, an increase in shear is observed. The amount of displacement of the structure in nonlinear static analysis is equivalent to removing one column and bracing more than the previous case. The results show that by removing the column and bracing simultaneously, the progressive collapse will probably mostly occur in elements close to the part to which the failure scenario is applied.