摘要: |
Approximately 1,200 tornadoes impact the United States every year with a percentage of these resulting in significant damage, injuries, and fatalities. Initially, a probabilistic tornado hazard analysis was performed in order to develop tornado hazard curves at select locations across the United States. This analysis resulted in the annual probability of experiencing a tornado of any strength at the specific locations, which varied as a function of location-specific occurrence rates. Five different residential wood-frame building archetypes were designed at each of the locations based on current residential building code and/or practice. Fragilities for the roof sheathing and truss to wall top-plate connections were developed for each archetype. Because fragilities are independent of location, they were then convolved with the tom ado hazard curves to compute annual failure probabilities for select roof components. This represents the first time absolute risk of roof failure due to tornadoes has been computed since the tornado hazard curve is convolved with the fragility curves. These probabilities quantify failure probabilities of residential wood-frame roofs to tornado winds. While this value is quite small for an individual home, applying this method to an individual city block or neighborhood can quantify a location's vulnerability to tornado wind damage. The Florida state building code is applied to other locations in the United States, fragilities are developed and convolved, and failure probabilities for these modified buildings are computed. The comparison of failure probabilities between local building code and the stricter Florida residential building code allowed for a quantitative assessment of strengthened construction practices for structures subjected to tomadic wind loads. Results indicate that stricter building codes may be beneficial in areas with a high annual tornado risk, such as Tornado Alley. DOI: 10.1061/(ASCE)ST .1943-541X.0001353. © 2015 American Society of Civil Engineers. |