Commercial and Residential Building Performance during the May 20, 2013, Tornado in Moore, Oklahoma

In 2013, there were 14 killer tornadoes in the United States that caused a total of 55 fatalities. The most severe tornado in this group was an Enhanced Fujita (EF) 5 storm that occurred on May 20 in Moore, Oklahoma. Because of the severity of this storm, a field investigation was undertaken to observe and document damaged commercial and residential structures so that a better appreciation of their structural and nonstructural performance could be developed. Both low-rise engineered commercial buildings and single-family homes were surveyed. Most of the commercial buildings sustained severe nonstructural damage and limited damage to the primary structural system. However, some instances of global structural collapse and local collapse of structural elements around building entrances were also observed in commercial buildings. Residential construction exhibited extensive damage to brick veneer and failure of garage doors and subsequent roof damage. These failures illustrate the importance of an adequate load path from the building façade back into the primary structural system. Furthermore, maintaining the integrity of the façade and roof systems is critical because failure of these systems was observed to change the loading and support conditions of key structural elements, which then precipitated damage to the primary structural system.