An efficient wind field simulation technique for bridges

To perform a time-domain aerodynamic analysis for bridges, it is necessary to develop an efficient simulation scheme which generates wind velocity histories at locations along the bridge span with some given spectral density distributions. The spectral representation method is an unconditionally stable simulation approach. However, it becomes computationally prohibitive to simulate multidimensional processes. A modified spectral representation method is developed to generate the spanwise wind turbulence field for bridges. The method is based on the original spectral representation method under the assumptions that the bridge deck is on the same elevation and the wind field is homogeneous along the spanwise direction of the bridge. It is also assumed that the wind velocities are simulated at locations equally distributed along the bridge span. The current method requires neither Cholesky decomposition nor modal factorization, thus is more efficient than the original spectral representation method when a large number of wind processes are to be simulated. Numerical results show that the current method can save up to 50% of CPU time for one hundred wind velocity processes, when compared to the original spectral representation method using modal factorization with fifty modes.