The Effect of Column Location and Bracing on Progressive Collapse of Steel Structures

During their service lives, the buildings may be exposed with natural or human-made threats. Considering the shock nature of the  loads caused by explosions or seismic events, it is likely that columns are eliminated suddenly when being subject to these loads and lose their bearing capacity. Some structural ele-ments are particularly important to reduce collapse progressive mechanism. Bracing elements are thought to be effective in preventing structural collapse. Among modern bracing types, buckling restrained brace (BRB) is a type of bracing commonly used in structures. These kinds of braces have similar behavior in tension and compression. Therefore they have high likelihood of attracting energy through submitting brace in tension and compression and are commonly known as hysteretic dampers. This paper investigates the performance of structures after middle and corner column eliminated and how the presence of braces redirect the load path preventing total collapse of the structure. Pushover analysis is used on a steel structure that is equipped with BRB. The structure is designed based on the sixth and tenth chapters of Iranian National Building Regulations.