Experimental study of wind loads on typical single-circuit transmission towers

Owing to the vast difference in geometries between a superstructure and a lattice body, the typical transmission towers tested in this study were divided into three sections: the superstructure, the body and the leg section. Individual high-frequency force-balance tests were performed on two types of superstructures and on a lattice body. Variations in the mean and root mean square force coefficients with varying wind incidence angles were investigated. The experimental results were compared with existing codes and the results of previous studies. Based on analyses of the power spectral density and coherence of the wind forces, the mechanisms producing the wind loads acting on the lattice structures are discussed. The results indicate similar magnitudes of the along-wind, across-wind and torsional dynamic wind loads on the superstructures. In contrast, the dynamic wind forces on the lattice body primarily act in the along-wind and across-wind directions, with a negligible torsion effect. The across-wind force and torsional moment on the lattice tower is likely produced by a large-scale wake induced by interference among the wakes of the lattice members.