Experiment on wind force on typical superstructures of latticed transmission tower

Two types of typical superstructures of latticed transmission tower(SLTT) have been tested in TJ-1 wind tunnel in Tongji University using a high-frequency-force-balance technique to investigate the characteristics of wind forces acting on the superstructures.The mean and RMS force coefficients in body coordinate system were obtained from the tests.The variations of these coefficients with wind angles are investigated,and the effects of wind turbulence and the shapes of SLTT on wind force are also discussed.The results indicate that alongwind wind force is the major load on the SLTT for the static wind effects,while magnitudes of the along-wind,across-wind and torsional fluctuating loads are all great.And,the mean force coefficients have no practical variability with turbulence.The correlation of along-wind with across-wind,torsional forces is small,but across-wind with torsional force has some correlation.And wind angles and wind field has great influence on it.Based on the analysis of power spectrum densities(PSDs) of the forces,some conclusions are drawn that incoming wind turbulence has great contributions to the along-wind forces,and PSD of across-wind forces is more complicated,multiple excitations may be existed.In addition, the torsional PSD is broadband spectrum,incoming wind turbulence and vortex shedding are main excitations.