  Past severe earthquakes, such as Bam earthquake of 2003 and Tabas earthquake
of 1978, have demonstrated that many cities in Iran are prone to be struck by
near-fault earthquakes. Such earthquakes are impulsive in nature, and
therefore, they are more destructive than the ordinary ground shaking. In the
fourth edition of Iranian seismic code (Standard No. 2800), some changes,
including a modification factor for the elastic acceleration response spectrum
(EARS) have been recently recommended to reflect the effects of such probable
near-fault earthquakes for the designing procedure. In this study, a numbers of
2D RC moment resisting frames (MRFs), from four to twelve story buildings, are
designed linearly based on Iranian National Building Code (INBC) and Standard
No. 2800 as well. Subsequently, their nonlinear models are reproduced for
conducting nonlinear dynamic time history (NDTH) analysis. For this purpose,
twenty impulsive ground motions are selected and scaled to be compatible with
the design basis earthquake (DBE) spectrum of the abovementioned code. It is
concluded that the seismic performance of the analyzed structures are not
satisfactory at all; no buildings are successful to satisfy the life safety
(LS) performance level posed by guidelines such as ASCE41-06 or ASCE41-13.
Moreover, it is worth mentioning that even collapse prevention (CP) limit
states are not also met in some cases. Therefore, the recently added
modifications in the Standard No. 2800 may be inadequate to incorporate the
near-fault earthquakes' effects.
