Application of weathering steel to steel towers for transmission line

From the point of visual impression, we often use beautified towers painted to harmonize with their surroundings. So we expected that rust on steel looks like painted steel, we focused on weathering steel often used on bridges. In 1975, we experimentally applied angle steel towers used weathering steel (nontreated) to our transmission line in consideration of deterioration of steel strength by contamination, and, in 2000, we experimentally applied tubular steel towers (consists of CFT: concrete filled steel tubes) used weathering steel (treated) to our transmission line.