2003 Volume 28 Issue 4 Pages 97_121-97_136
High-voltage transmission lines with an overall length of several hundreds kilometers have been constructed across the mountainous area or the coastal zone, and directional strength characteristics of the transmission tower are found remarkably due to a high rate of wind load. Transmission towers are considered to be designed with enough wind-resistance performance, however, it is necessary to re-examine the current estimation methods from both points of design wind speed and wind load to rationalize the tower design and to improve the structural integrity. In this paper, considering the rationalization of design wind speed, we analysed statistically wind speed data at about 140 meteorological observatories in Japan, resulting 150-year return period wind speed every 8 directions, and simultaneously excuted air flow simulations of the Japanese Islands divided into 4 parts. Using these results, we show a new attempt of basic wind maps showing the 150-year return period of annual maximum 10 minutes-mean wind speed by direction at 10 m above class II roughness terrain.
