Tornadoes represent a unique natural hazard because of the very low probability of
occurrence, short warning times (on the order of only a few minutes), and the intense and
destructive forces imposed on engineered and non-engineered buildings. The very low-probability very high-consequence nature of a tornado strike makes designing for
survival and reducing damage under typical financial constraints a substantial challenge.
On April 27, 2011 an EF4 tornado devastated a 0.8 km (1/2 mile) wide path almost 10
km (5.9 miles) long through the city of Tuscaloosa, Alabama continuing on the ground
for 130 km (80 miles). This paper presents the design concept that resulted following a
week-long data reconnaissance deployment throughout the city of Tuscaloosa by the
authors. The dual-objective philosophy proposed herein is intended to focus on both
building damage and loss reduction in low to moderate tornado windspeeds and building
occupant life safety in more damaging wind speed events such as EF4 and EF5
tornadoes. The philosophy articulates a design methodology that is the basis upon which
structural engineering was formed, namely provide life safety and control damage, but
focused at separate tornado intensity levels.Keywords: Residential building, Design method, Natural hazard, TornadoKeywords: Residential building, Design method, Natural hazard, Tornad
