Abstract
Since the wind load is critical for the design of transmission lines, it is important to assess the design wind speed reasonably at construction sites. Wind loads acting on the transmission tower usually vary greatly by direction because of the structural characteristics. However, in the current design method of transmission towers, non-directional basic wind speed is applied in Japan, and therefore in many cases this may result in overestimation. In this paper, a method to estimate directional basic wind speed for the transmission tower design is proposed. The return period of the directional wind speed is estimated keeping the same non-exceeding probability of occurring stresses as the current design method. Then directional basic wind speeds at meteorological stations are determined by comparing with the typhoon simulation results.
