Dynamic impact induced by tornadoes through simulations based on two-way wind-structure interactions

Tornadoes have become a significant cause of property damage, injuries and life losses. Investigations of tornadoes indicate that most fatalities were caused by building failure. For example, in the Joplin, MO tornado of 22 May 2011, 161 people were killed, and 84% fatalities were related to building failure. Therefore, it is imperative to develop science-based tornado-resistant building codes, in order to provide a better level of occupant protection from tornadoes and to minimize the tornado-induced damage. This requires in-depth understanding of the wind characteristics of tornadoes and their wind effects on civil structures, based on which design tornadic wind loading can be properly determined. To achieve this, in this study, Computational Fluid Dynamics (CFD) simulations and Computational Structural Dynamics (CSD) simulations are combined for the first time to systematically investigate tornado dynamics and its dynamic impact on civil structures. First, wind effects on large-scale space structures induced by straight-line winds are investigated to fully understand the current building code against wind loads. Then, a real-world tornado is numerically simulated and verified based on full-scale radar-measured data. Based on the verified CFD model, non-stationary wind characteristics of tornadoes and the induced wind effects on large-scale space structures are investigated under different flow structures of tornadoes. Next, CFD and CSD are combined to investigate tornado-induced dynamic responses of large-scale space structures. Finally, tornado-induced dynamic responses of large-scale space structures are compared with that induced by the equivalent straight-line winds, in order to properly modify the equation for calculating the design wind pressure specified in ASCE7-16 --Abstract, page iv