Robustness evaluation of fiv3 using near-fault pulse-like ground motions

Abstract

A robust intensity measure (IM) is one that provides stable structural response estimates when using ground motion records having a wide range of characteristics. This paper evaluates the robustness of collapse risk estimates of two 4-story structures using the new IM, FIV3, along with several ground motion sets having non– and pulse-like ground motions. Comparisons with the most common IM, the spectral acceleration at the first-mode period of the structure (Sa), Sa adjusted by ε, and Saavg, indicate that FIV3 is much more efficient, sufficient with respect to the pulse period ratio, and robust with respect to scale factor in the case of these low-rise moment frame buildings. Moreover, by using FIV3 the proportion of near-fault pulse-like ground motions included in the ground motion set or various characteristics of the ground motions have a minor influence in the results, meaning that results are far less sensitive to the ground motion set used in the evaluation than when other IMs are used. These results suggest that the ground motion selection process could be greatly simplified if FIV3 is used as the IM because deaggregation procedures aimed at estimating the ‘correct’ proportion of expected pulse-like ground motions or their pulse period distributions might no longer be necessary.