Authors : Mojtaba Harati, Ahmad Hojjati Sabet and Ataollah Hajati Modaraei
Abstract: 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 4th 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 4-12 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 Non-linear Dynamic Time History (NDTH) analysis. For this purpose, twenty impulsive ground motions are selected and scaled to be compatible with the Designed Based Earthquake (DBE) spectrum of the above mentioned 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 incorporatethe near-fault earthquakes’ effects. At the end some recommendations are addressed for the design of structures built in the regions vulnerable to be attacked by near-fault earthquakes.
Mojtaba Harati, Ahmad Hojjati Sabet and Ataollah Hajati Modaraei, 2016. An Investigation on the Effect of the Near-Fault Earthquakes on the Seismic Behavior of RC Moment Resisting Frames (MRFs) Designed Based on Iranian Seismic Code (Standard No. 2800). Journal of Engineering and Applied Sciences, 11: 274-283.