progressive collapse analysis and comparison of intermediate and special steel moment frame under fire conditions

Progressive collapse occurs when any one of load carrying members is removed or damaged suddenly and other structural elements are not able to support the weight of the building, so this causes a local or global failure in the structure.fire, blast ,design/construction error, vehicle impact and abnormal loads such as strong ground motions are the main reasons for the progressive collapse of structures. due to local fire, one or more structural members may be damaged; it can cause local damage and following that progressive collapse in the building. the aim of this paper is to investigate the progressive behavior of a different type of steel frames under fire conditions. for this purpose, an intermediate and specialsteel moment frame are designed according to part six and ten of iranian national building codes and requirements of fourth edition of standard no. 2800 using etabs software. then the progressive collapse behavior under fire load based on ufccode and using the nonlinear dynamic analysis method has been investigated using opensees. opensees is an open-source object-oriented software framework developed at uc berkeley.