Selection of Ground Motion Intensity Measures in Fragility Analysis of a Mega-Scale Steel Frame Structure at Separate Limit States: A Case Study

Selecting an appropriate ground motion intensity measure (IM) to estimate the aleatory uncertainty produced by variability is first and crucial step in fragility analysis. The choice of IM influenced not only structural system type itself but also limit state damage. In this study, investigation selection analysis with respect different states developed for a 48-story mega-scale steel frame structure buckling restrained braces. A comparative study efficiency 27 IMs conducted at four damage states, i.e., negligible, light, moderate, severe, through lognormal standard deviation estimated equations. addition, purpose considering influence earthquake characteristics, two completely sets motions are selected, namely near-field pulse-like far-field earthquakes. research shows that characteristics have nonnegligible effects on flexibility measures. For combination-type IMs, number combined terms power index significant impact their performance; thus, optimized dual-parameter recommended.