Structural Observations and Tornado Damage Mitigation Concepts: March 2020 Tennessee Tornadoes

Early in the morning of March 3, 2020, a storm system producing multiple tornadoes passed through middle Tennessee. One of the tornadoes—touching down in Cookeville and Putnam County—was classified as an EF4 with winds of approximately 282 km/h (175 mph). Damage observations after the tornado in Cookeville suggest that modifications to certain common construction practices might significantly enhance resistance to extreme wind forces. This paper provides recommendations for improving strength and resiliency within residential structures, particularly in four critical areas: (1) stiffness and strength of gable trusses, (2) wall-to-floor connections, (3) sill plate anchorage, and (4) shear and tensile capacity at interior foundation piers. Though improvements to construction practices are unlikely to eliminate damage to residential structures, such measures may well mitigate damage and extend the time between onset of the extreme forces and final damage or collapse.