Simulation of stochastic wind velocity field on long-span bridges

An improved algorithm is introduced in this paper for digital simulation of the stochastic wind velocity held on long-span bridges, when the cross-spe ctral density matrix of the held is given. The target wind velocity held is assumed to be a one-dimensional, multivariate, homogeneous stochastic proc ess. The basic method of simulation used is the spectral representation met hod. It is improved by explicitly expressing Cholesky's decomposition of th e cross-spectral density matrix in the form of algebraic formulas, then cut ting off as many as possible of the cosine terms, so long as the accuracy o f results is not affected. The fast Fourier transform technique is used to enhance the efficiency of computation. A numerical example of simulation fo r buffeting analysis is included in this paper to illustrate the improved m ethod introduced. It is demonstrated that deviations between the simulated correlation functions and the target are sufficiently small and that the si mulated power spectra are close to the target.