Engineering Observations of 3 May 1999 Oklahoma Tornado Damage

Abstract

On 3 May 1999, a severe tornado outbreak occurred in Oklahoma, Kansas, and other southwestern states. Because some of the tornadoes struck some highly populated areas, including Oklahoma City and its suburbs, they provided a vivid exhibition of the impact of hazardous natural forces on the built environment. The comparison of high-resolution aerial photography with ground-level damage assessment demonstrates that the damage state can be identified by observations from aerial images because most of the wind damage is done to the building envelope, especially the roof system. The high-resolution aerial photography enables rapid and fairly reliable damage assessments for large areas. Aerial and ground-level damage observations have again demonstrated that internal pressurization is a significant contributor to the progressive failure of the main wind-resisting frame following breaches to the building envelope. It is evident that the breaches to residential garage doors could lead to catastrophic roof failures.