A Study of Endurance Time Method in the Analysis of Elastic Moment Frames under Three-Directional Seismic Loading

Endurance Time (ET) method is a time history based analysis procedure that applies special intensifying acceleration functions for estimating the seismic performance of structures at different excitation levels in each single analysis. One of the extensions of the ET method is in the seismic assessment of buildings considering multi-component excitation. In this paper, a procedure for three-directional seismic analysis of buildings is proposed and application of this method to several steel moment frames is investigated. Several Steel Moment Frames were designed according to INBC Code. These Frames were analyzed under ET acceleration functions in horizontal and vertical directions simultaneously and results were compared to Response History Analysis. It is observed that ET method can predict the results from multi-component analysis, including vertical excitation, with reasonable accuracy. Scattering and accuracy of the results are also investigated.