عنوان مقاله [English]
The reliability of structures under different loading conditions is the main objective of civil engineers. Progressive collapse is a catastrophic phenomenon which has been of greatest interest to many researchers and engineers during the last decade. The incidence of diverse accidents such as burst, fire, vehicle collision, miscalculation, mistake in construction can result in a partial failure in a structure, which sometimes extends to collapse the majority of or entire a building. This phenomenon is called the progressive collapse. This collapse is defined in some regulations in the same way. For example in NISTIR-7396 “the progressive collapse is the expansion of a primary damage triggered by a primer incident from an organ to others consequently causing either major or entire damage to a construction”. The main aim of this project is to study the reaction of the steel moment frame with the rigid connection of SP, WUF-B and RBS under the progressive collapse.
To pursue the study, we used six-, nine- and 12-floor buildings representing short, mid and tall structures equipped by the steel moment frame system. The alternative path method and UFC 4-023-03 regulation were used as standard methods to estimate the progressive collapse. The modelling of the buildings was run by software SAP 2000 which is in 3D, and then non-linear dynamic time history performed to analyse the data. Moreover, we predicted the different scenarios of column removals regarding the regulation criteria in order to study the progressive collapse.
The results from the alternative path method showed that unlike the WUF-B and SP connections, the RBS has more potential resistance due to higher ductility. Furthermore, the tall buildings presented the better resistance against collapse as well, because of the higher indeterminate degree. The results from column removals in the given models showed the more destruction in the upper floors unlike the removals of columns in downward floors.