Design, construction and performance of a large tornado simulator for wind engineering applications

Current design wind loads for buildings and other structures are based upon model tests in low-speed boundary-layer wind tunnels that generate straight-line winds. Winds resulting from tornadoes that can occur during extreme weather events such as thunderstorms or hurricanes differ greatly from conventionally conceived atmospheric boundary-layer winds. This paper presents transient wind loads on a one-story, gable-roofed building in a laboratory-simulated tornado and compares them with the provisions of building standards. Tornadoes were simulated in smooth, open terrain with vortex core diameters from roughly five to twelve times the plan dimension of the building model (0.46 to 1.06 m). A 1:100 scale model of a building with dimensions of 9.1 m×9.1 m×6.6 m and gable roof angle of 35° was used for this study. Comparisons of peak loads measured in this study showed that tornado-like vortices can generate load coefficients greater than those prescribed by ASCE 7-05 for straight-line wind over open terrain....

https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=15859&context=rtd

Tornado-induced wind loads on a low-rise building

Thunderstorms—their importance in wind engineering (a case for the next generation wind tunnel)

This paper presents both quasi-steady and transient wind load effects on a cubic building in a microburst and a tornado. Large eddy simulation (LES) was used to simulate the loading effects of a translating microburst with a 0.20-m-diameter jet at four different translating velocities on a 25 mm cube. The results of the numerical simulation were compared with data from a laboratory microburst simulator. The numerical simulation predicted an increase in drag forces with increase in microburst translation speed. The transient loading effects on a 229 mm cubic building from a translating tornado were also simulated in a laboratory for two different vortex core diameters and two translating speeds and the peak loads were studied. Results for the cubic building were compared with that of a tall building under the same loading conditions. Finally, peak loads and peak moments measured in this study were compared to the corresponding values specified in ASCE 7-05 [2006. Minimum Design Loads for Buildings and Other Structures, 2006. ASCE Standard, SEI/ASCE 7-05, American Society of Civil Engineers] and found to exceed them by a factor of 1.5 or more for buildings located in tornado alley of the United States subjected to tornadoes of F2 or higher intensity.

M.C. Jischke

Papers

Laboratory simulation of tornadic wind loads on a rectangular model structure