Studying near fault endurance time acceleration function

The endurance time (et) method is a time-history based dynamic pushoverprocedure. in this method, the structures are subjected to gradually intensifyingacceleration called an acceleration function. then, their performances are assessed fromlinear to collapse level based on the interval time through which they can satisfy the requiredobjectives. et acceleration functions (etafs) are calibrated upon actual earthquakespectra compatible with the iranian national building code (standard no. 2800). inthis code, there is no distinction between far and near fault regions. etafs scale basedspectrum increases uniformly at all periods as the time passes which is why this uniformincrement is not desirable in near fault earthquakes. as the rupture propagation is orientedtowards a site, near fault earthquakes have further spectral acceleration in the period over0.6 sec compared to far fault earthquakes. the shape of the spectrum becomes richer overlong periods as its level increases. in this research, etafs are presented for near faulttarget spectra, provided by abrahamson-silva attenuation relations. these relations havebeen modied by somerville near fault correction coecients. according to the resultsobtained in this research, while the new acceleration function can model directivity eectsat higher periods, it also satises endurance time concepts.