PROGRESSIVE COLLAPSE RESISTANCE OF RC FRAMED BUILDINGS WITH DIFFERENT DUCTILITES

The reliability of structures under dierent loading conditions is the main objective of civil engineers. Experiments show that buildings may be vulnerable to blast air pressure and localized failures that occur in them. The cause of the explosion could be accidental or intentional, e.g., happened by terrorist attacks on public or private buildings. Progressive collapse is a catastrophic phenomenon which has been of greatest interest to many researchers and engineers during the last decade. Therefore, in this study, RC framed structures designed in accordance with Iranian design codes are evaluated using the GSA guidelines in order to investigate their progressive collapse potential. A ve-story building is used to evaluate the impact of structural ductility on the progressive collapse that has a regular plan. The building blocks are designed for low, medium, and high ductile moment frames. In this study, the performance evaluation of progressive collapse conducted on buildings, and it shall include three dierent locations for removal of columns in the building plan. In addition to assessing the impact of locating columns in dierent locations, column removal is performed in stories 1, 3, and 5. In fact, in every building, there are 9 column removal scenarios; all these scenarios are analyzed for both methods of static and dynamic analyses. The structures are designed according to the conventional Iranian design codes, and afterwards evaluated using both nonlinear dynamic and nonlinear static analyses following dierent column removals. The column removals' static and dynamic analyses to assess the buildings are designed by dierent ductilities; it is concluded that the potential progressive collapse of the special moment frames is very much more than intermediate and ordinary moment frames. Based on the load combination specied by the GSA, ordinary and intermediate frames can withstand collapse up to overload factors of 1.8 and 1.33, respec- tively. On the contrary, the special moment-resisting frame cannot resist against progressive collapse, and several column removals lead to collapse. In fact, this may suggest that a special seismic design, while more ductile compared to an ordinary design, does not necessarily have a better performance under a column removal scenario.