In the recent damages on structures due to tornadoes, the major failure occurred on the cladding of walls, roofs, and ceilings etc. The main reason is the suction between the both sides of the cladding. For these matters, the numerous numbers of the pressure measurement tests using the wind tunnel were conducted and the phenomenon and its reasons were verified. So the external pressure acting on the claddings can be estimated, however, so far it is difficult to estimate the strength of the cladding and its supporting systems. In this paper, the way to verify the strength of the cladding system is shown. The static and dynamic characteristics of arbitrary eaves soffit system using the pressure chamber are verified.

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To investigate the overshoot phenomenon of wind force caused by sudden changes of wind velocity, we measured wind forces acting on gable roof structures by a gust wind tunnel test and simulated the experimental results using CFD analysis. Our result showed that although the occurrence time of an overshoot peak drag force was different from that of a lift force, the bigger peak of drag and lift forces were generated by a gust wind with a shorter non-dimensional rise time. It was found that the first peak drag force appeared during an increasing gust wind velocity and a peak lift force followed after the gust reached a target wind velocity.

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Once there was a long span of transmission line crossing the Naruto straits. The transmission line was planed to build in 1950s. An intensive study of wind in the area was made and the design wind speed over the straits was established. The transmission line was built in 1961 and used until 1985. At that time when the line was built, the span of line was the longest in Japan. Throughout the history of wind engineering in Japan the study was the first attempt to establish the design wind speed for large-scale structures such as transmission lines. An outline of this historical study has been shown.

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This report provides an overview of the tornado impact on the safe operation and shutdown of nuclear power plants in the United States. The motivation for this review stems from the damage and failure of the Fukushima nuclear power plant on March 11, 2011. That disaster warrants comparison of the safety measures in place within the global nuclear power industry.

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