![]() ĭevelopment of a Probabilistic Tornado Wind Hazard Model for the Continental United States Volume I: Main Report However, since no tornadoes have been classified to exceed F-5, the F-6 through F-12 categories have no practical meaning. ![]() Note that F-6 through F-12 are for wind speeds between 319 mi/hr (mph) and the sonic velocity (approximately 760 mph 1 mph = 1.6 km/kr). The wind speed (maximum gust speed) associated with each F number is given in Table 1. The F scale classifies tornadoes into 13 numbers, F-0 through F-12. National Weather Service has been using the well-known Fujita scale (F scale) to estimate the maximum wind speeds of tornadoes. The sensitivity of wind speed probability estimates to various tornado modeling assumptions are examined, and the probability distributions of tornado wind speed that are needed for load combination studies are presented.Ĭalculation of wind speeds required to damage or destroy buildingsĭetermination of wind speeds required to damage or destroy a building is important not only for the improvement of building design and construction but also for the estimation of wind speeds in tornadoes and other damaging storms. A unified model was developed which synthesized the desired aspects of tornado occurrence and damage potential. Several proposed models were evaluated for predicting tornado wind speed probabilities at nuclear plant sites as part of a program to develop statistical data on tornadoes needed for probability-based load combination analysis. These PRAs indicate that the guidelines will lead to facilities that meet the US Department of Energy (DOE) design requirements and that the Nuclear Regulatory Commission guidelines adopted by the DOE for design are adequate to meet the NPR safety goals.« less Simplified probabilistic risk analyses (PRAs)more » for wind speeds and missile impact were performed to estimate annual damage risk frequencies for both the INEL and SR sites. The basic philosophy was to select realistic wind and missile load specifications, and to meet performance goals by applying conservative structural response evaluation and acceptance criteria. The Wind/Tornado Working Group (WTWG), comprising six nationally recognized experts in structural engineering, wind engineering, and meteorology, formulated an independent set of guidelines based on site-specific wind/tornado hazard curves and state-of-the-art tornado missile technology. ![]() This report documents the strategy employed to develop recommended wind/tornado hazard design guidelines for a New Production Reactor (NRP) currently planned for either the Idaho National Engineering Laboratory (INEL) or the Savannah River (SR) site. Our findings show that students lack understanding of the fundamental concepts that (1) tornadoes are… To ascertain novice conceptions of tornado wind speed and the influence of surface characteristics on tornado occurrence, 613 undergraduate students enrolled in introductory science courses at a large state university in Nebraska were surveyed. 31 references, 8 figures, 2 tables.« lessĬonceptions of Tornado Wind Speed and Land Surface Interactions among Undergraduate Students in NebraskaĮRIC Educational Resources Information Center Some progress in computer simulation of tornado missiles have been made. Type of construction, age of construction, materials and other constructionmore » features significantly affect structural performance of a building subjected to wind loads and should be taken into account in assigning Fujita-Scale ratings (3) damage to forests gives a good indication of tornado wind field flow patterns, but do not give verifiable values of wind speed (4) factors such as translational speed, wind direction and path width affect appearance of damage or a tornado and (5) even the most awesome appearing missiles do not require incredible wind speeds to explain them. The results indicate: (1) maximum tornado wind speed ever experienced or expected is in the range of 250 to 300 mph (2) appearance of damage, taken by itself, is a misleading parameter of tornado intensity. Because there were no significant tornado events (F4 or greater) during the contract performance period, data from the literature and the files of the Institute for Disaster Research were used to perform the analyses. DOE Office of Scientific and Technical Information (OSTI.GOV)Ī study of near-ground tornado wind fields has been conducted by inspecting damage and debris patterns found in tornado damage paths.
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