Simulation and Analysis of Tornado-Induced Loads on Low-rise Buildings
Abstract
This thesis presents an analysis and simulation framework for evaluating tornado-induced wind loads on low-rise buildings. The research addresses a gap in understanding the interactions between tornado wind fields and building structures, which are not fully captured by existing design codes. This methodology enables the simulation of aerodynamic, static, and internal pressure loads, offering a framework for assessing a wide spectrum of tornado-induced wind loads. By varying key parameters, like tornado intensity, core radius, and building position relative to the tornado path, the study captures the variability in load distributions, highlighting the role of aerodynamic loads in horizontal directions which account for 80% - 90% of the total horizontal loads. In addition, the research investigates the effects of tornado translation speed on load distribution, finding that slower-moving tornadoes generally result in higher loads, particularly for stronger tornadoes (EF3 and above). The position of the worst load cases shifts with increasing tornado intensity, often occurring near the radius of maximum winds, where aerodynamic pressure effects are most pronounced. The study also reveals that building orientation and opening configurations significantly influence the distribution and magnitude of loads, with buildings aligned perpendicular to the tornado path experiencing the highest forces. Validation against experimental data confirms the framework’s acceptable accuracy in predicting worst-case scenarios. Key findings reveal that while aerodynamic loads dominate for large tornadoes, static pressure effects are critical for smaller tornadoes, especially with the building within the vortex core. These findings have implications in the tornado rating process, which depends on wind speed estimates.