Seismic Meta-Fragility Functions

Abstract

Fragility functions make for one of the three key components of probabilistic seismic risk analysis, along with hazard and consequence and/or exposure models. They are, in principle, construction-specific; however, risk analysis is more often performed on a larger (e.g., regional) scale. In this case, so-called typological fragility curves are intended to be applied to populations (i.e., classes) of structures, rather than to any of its members specifically. When these curves are obtained via mechanical/numerical approaches, they are typically based on numerical models, intended to be representative of the class of interest. In the short communication, an approach that reconciles class-scale and structure-specific vulnerability in the derivation of fragility functions is discussed. It materializes into a hierarchical model degenerating in a fragility function conditionally to the construction-specific information, yet it can be used for large scale risk assessment when such information is uncertain. To derive the meta-fragility, among other options, the response-surface approach is discussed. In the way it is postulated, such modeling approach can be used also to derive fragility from earthquake damage observations.