Dominant failure modes of a transmission tower and its ultimate capacity under wind load

This paper analyzes the dominant failure modes of a transmission tower and its ultimate basic wind pressure under equivalent static wind load in the along-wind and across-wind directions. Finite element model of the transmission tower based on space truss structure is established. A method in terms of basic wind pressure is introduced to generate dominant failure modes of the transmission tower, as well as the ultimate basic wind pressure. Furthurly, This paper discusses the influence of wind load in the across-wind direction on dominant failure modes of the tower and on the ultimate capacity. A numerical example indicates that if equivalent static wind loads in across-wind direction are neglected, the ultimate wind pressure of the transmission tower will be overestimated. At the same time, it is suggested that the structure capacity in resisting wind load can be improved effectively and efficiently if the strength of a small number of basic failure elements is improved.