This paper investigates the relative effects of strong-motion variability and random structural parameters on seismic vulnerability curves, also studying the impact of statistical model selection. A three-story reinforced concrete frame, previously shake-table tested, undergoes fragility analysis. The analytical environment and structural model are verified against shake-table test results. Ground motion selection, limit state definition, statistical manipulation of simulation results, and material variability effects are examined. Results suggest that material response parameter randomness is less significant than strong-motion characteristics, emphasizing careful strong-motion selection and scaling, appropriate limit states, and statistical models.
