Minimal Building Fragility Portfolio for Damage Assessment of Communities Subjected to Tornadoes

Tornadoes are considered a low-probability high-consequence event that can cause significant damage to community infrastructure, resulting in injuries and fatalities and ultimately creating long-term socioeconomic losses. Community resilience requires not only that the performance level of individual facilities be modeled and understood, but also their synthesis in space and time. Fragilities are conditional statistical distributions that provide the probability of exceeding analyst-defined performance levels as a function of hazard (or loading) intensity. Fragilities are becoming a core component in community resilience studies and enable the analyst to model performance of individual components or a cluster of the infrastructure, thereby supporting risk-informed decision making at the community level. In this paper, tornado fragilities for a portfolio of nonresidential buildings are developed. These fragilities, combined with several existing tornado building fragilities from the literature, are proposed to represent a first comprehensive minimum size portfolio of tornado building fragilities needed to model a community. For illustration, they are then used in the Centerville virtual community to perform community-level building damage assessment. This minimal-level portfolio of building fragilities lays the foundation for post-tornado recovery and resilience studies of a community, which eventually requires inclusion of all physical and nonphysical infrastructure.