Estimation of dynamic wind forces on a steel lattice tower based on generalized wind force spectra

Abstract

This article presents a method for estimating dynamic wind forces on a steel lattice tower. The spectra of local wind forces are derived based on generalized wind force spectra, which have considered the coherence between different axial wind forces under the skewed wind. With the established cross-power spectral density (PSD) matrix of wind forces, the fluctuating wind forces can be simulated in the time domain using the harmony superposition method. The wind tunnel experiments on a typical transmission steel lattice tower are introduced. Using the test data, the coherence of wind forces on different body axes is analyzed, and the corresponding empirical function is fitted. With the empirical PSDs of the generalized forces obtained in the previous wind tunnel experiments, the dynamic wind forces on the transmission tower are simulated in target wind environments. The dynamic responses of the tower are calculated under the estimated wind forces and compared with the measurements in the aeroelastic wind tunnel experiments. Results reveal that the proposed approach to estimating distributed dynamic wind forces on a steel lattice tower performs effectively.