On the Seismic Resilience

The concepts of seismic resilience need a unified terminology and a common reference frame for quantitative evaluation of such resilience. The evaluation can be based on non-dimensional analytical functions related to loss variation within a specified “recovery period”. The path to recovery usually depends on available resources and may take different shapes which can be estimated by proper recovery functions. The loss functions have uncertainties due to the nature of the earthquake, structural behavior and the description of functionality limits. Therefore losses can be described as functions of fragility of systems’ components. These fragility functions can be determined through the use of multidimensional performance limit thresholds, which allow consideration of simultaneously different mechanicalphysical variables. A procedure which defines resilience as function of losses and time recovery based on multidimensional fragility system is formulated and exemplified for a typical California hospital building considering direct and indirect losses in its physical system and in the population served by the system.