Failure Progression Analysis of Observed Residential Structural Damage within a Tornado Wind Field

Abstract

Data collected from recent tornadoes in Tuscaloosa, Joplin, and Moore shows a consistent pattern of damage to residential structures. For an EF-4 or EF-5 tornado, damage levels increase from the outer edges toward to the center line of a tornado track. This is not just because of higher wind speeds at the center of a tornado vortex; the wind velocity fields around structures are also different at the tornado center. Analysis from the damage pattern from the tornado showed that the failure progression of residential structures within a tornado wind field depends on the relative location and direction of the house to the tornado track. With the same wind speed, different damage levels can be observed if structures located in different relative distances from the center-line of a tornado damage track. This should be considered when predicting tornado wind speed based on residential structural damage.