Characteristics of Second Generation Endurance Time Acceleration Functions


Department of Civil Engineering,Sharif University of Technology


The Endurance Time (ET) method is a time-history based dynamic pushover procedure
in which structures are subjected to specially designed, intensifying accelerograms, and their seismic
performance is judged based on the time duration needed to satisfy the required design objective. Second
generation refers to ET acceleration functions that are generated by application of optimization techniques
in order to produce response spectra compliant linearly intensifying accelerograms. In this paper, the major
characteristics of a set of second generation ET acceleration functions (ETA20a01-3) are investigated.
The template response spectra of this set of ET acceleration functions corresponds to the design spectra
of the Iranian National Building Code (Standard 2800) for sti soil (type II). Results show that a good
correspondence can be established between the e ective ground motion parameters of earthquakes and ET
acceleration functions at speci c target times. Therefore, it is expected that ET acceleration functions can
be used to predict various demand parameters of structures subjected to ground motions whose response
spectra is more or less compatible with the adopted template response spectra. Discrepancies between
characteristics of ET acceleration functions and ground motions have also been discussed.