Experimental Investigation of Tornado Induced Pressures on Residential Buildings

Several tornadoes occur each year in Canada, while design guidelines for building structures to withstand tornado events are still in incipient stage. The novel Wind-induced Damage Simulator (WDS) built at the University of Ottawa, capable of simulating pressures induced by multidirectional and tornadic winds was used to test a 1:100 scaled house model in a simulated tornado of 16.5 m/s maximum tangential wind velocity. Three orientation angles of the model placed at three locations along the radius of the tornado were investigated. This replicated different conditions the tornadic flow would approach a residential house. These locations were selected based on a preliminary analysis conducted for 750RPM, 825RPM and 900RPM fan velocities, to characterize the tornado maximum velocity and radius simulated in the WDS facility. The model was instrumented with 96 pressure taps along the roof and the lateral walls and the external pressure coefficients were determined. Negative pressure coefficients of up to −1, were recorded for the roof and wall sides exposed to the tangential velocity of the tornado, for all the investigated cases. The magnitude of the pressure coefficients was found to be in good agreement with the results reported by [2], for same dimensions house model tested in a laboratory simulated tornado, however the pressure distributions on the surface of the tested model were different due to the different tangential velocity simulated in the WDS facility.