A methodology to assess and select seismic fragility curves: Calibration from expert survey and fuzzy analysis

Fragility curves (FCs) are extended decision-making tools for estimating the structural performance of systems exposed to seismic hazards. However, selecting an inappropriate FC can significantly affect the accuracy of loss and damage calculations in seismic risk assessments.

This article enhances the “Select.FC” method, a recently proposed novel approach that allows the selection of FCs with a higher degree of reliability. This method utilizes a multidimensional index incorporating a comprehensive set of variables about various aspects of FCs. A calibration and validation process is conducted on the variable scores of this multidimensional index based on a worldwide survey of experts. The implementation of the fuzzy analytic hierarchy process (FAHP) method further enhances the objectivity and dependability of the scores calculated from the experts' responses.

The proposed approach not only allows for the evaluation of FCs but also provides a practical tool for researchers. This evaluation of FCs is crucial, as it enhances the accuracy and reliability of seismic vulnerability and risk assessments.

The results obtained from the expert survey and the FAHP reveal several discrepancies between the calibrated new scores assigned to specific variables and those proposed in the original methodology. However, in the aggregate, these discrepancies disappear. Therefore, the “Select.FC” method and its proposed classification of FCs into six categories based on the score obtained in the final multidimensional index seem quite robust regarding important changes in the weights of some of the variables.