The No.9119 typhoon which was very strong, 940 HPa, and ran through the Japan Islands longitudinally during 26-28th September 1991, caused unprecedented damages in transmission lines in West Japan. Immediately, electric power utilities organized a committee to investigate the cause and to take measures against local wind effected by topography, and asked Central Research Institute of Electric Power Industry (CRIEPI) to carry out the studies on the local wind resistance design of transmission tower-conductor systems. The purpose of this paper is to describe the summary of the investigation results and to show the outline of "Recommendations for local wind load on transmission towers - a draft".
Immediately after the No.9119 typhoon which caused severe damages in transmission lines in West Japan, electric power utilities asked Central Research Institute of Electric Power Industry (CRIEPI) to carry out the studies on the local wind resistance design of transmission tower-conductor systems. To promote the studies, CRIEPI organized a committee and three sub-committees (wind observation sub-committee, wind simulation sub-committee, and wind-resistance design sub-committee). The purpose of this paper is to describe the investigation results by the wind simulation sub-committee, which proposed a simple criterion of special topography, made a basic wind velocity maps, and developed a wind simulation computer program named "1-wind".
Multiple-fan wind tunnels have been developed in our laboratory to estimate the wind effects on large structures, such as high-rise buildings, long-span bridges, etc.. It is well known that natural turbulent wind can be analyzed by statistical factors, such as mean wind velocity,turbulent intensity, turbulent scale, power spectrum, Reynolds stress and so on. In the previous papers, it was shown that these factors were able to be simulated simultaneously in the multiple-fan wind tunnels. Moreover, to investigate the dynamic response of a large structure in a turbulent strong wind, spatial structure of the strong wind should be reproduced in the wind tunnels together with above factors. The spatial structure is expressed by coherence and phase-lag. It is shown in this paper that the coherence was obtained closely to the target by giving the phase-lag as a random function related to the coherence target.
Meteorological elements on the Tyhoon 9807(Vicki) were investigated with the weather observation network at fire stations in the Kinki and Chubu districts. There were 4 areas in Wakayama, Nara and Mie, where the daily maximum instantaneous wind velocities exceeded 50m/sec. At Tanabe City in Wakayama the daily maximum instantaneous wind velocity was measured almost simultaneously with the minimum atmospheric pressure. In the other areas the max instantaneous wind velocity was measured almost one-hour after the daily minimum atmospheric pressure occurred. The other meteorological elements on the ground in Typhoon 9807, temperature, humidity, precipitation and pressure, were measured in detail with the weather observation network at fire stations.
When the pressures on both sides of walls or roofs are measured simultaneously, or when the local pressures at a pointed or complicated shaped portion is measured, pipes or tubes connecting the pressure tap and the pressure transducer must be bent at rather acute angles. This paper discusses the applicability of bent pipes based on experimental results on its effects on fluctuating wind pressure signals. The experimental results have clarified that both the position of bend and the number of bend points can nearly be ignored, and that the effects of the sectional area of the bend point can be ignored when a brass bar with the same diameter as the inside diameter of the pipe is inserted into the pipes before they are bent.