Along-wind response of lattice towers—II. Aerodynamic damping and deflections

Abstract The analysis of the along-wind dynamic response of freestanding lattice towers in Part I, is continued in this paper. The expression for the ratio of the aerodynamic damping coefficient to the critical value is derived. The mean, background and resonant components of the deflection at the top of a tower, required for serviceability design considerations, are also derived. The results are all given in a ‘closed form’. Finally, the sensitivity of the gust response factors to calculation height, taper ratio and mean velocity, is investigated for a representative tower.