AN EFFICIENT WIND-FIELD SIMULATION TECHNIQUE FOR BRIDGES

To perform a time-domain aerodynamic analysis for bridges, it is neces sary to develop an efficient simulation scheme which generates wind ve locity histories at locations along the bridge span with some given sp ectral density distributions. The spectral representation method is an unconditionally stable simulation approach. However, it becomes compu tationally prohibitive to simulate multidimensional processes. A modif ied spectral representation method is developed to generate the spanwi se wind turbulence field for bridges. The method is based on the origi nal spectral representation method under the assumptions that the brid ge deck is on the same elevation and the wind field is homogeneous alo ng the spanwise direction of the bridge. It is also assumed that the w ind velocities are simulated at locations equally distributed along th e bridge span. The current method requires neither Cholesky decomposit ion nor modal factorization, thus is more efficient than the original spectral representation method when a large number of wind processes a re to be simulated. Numerical results show that the current method can save up to 50% of CPU time for one hundred wind velocity processes, w hen compared to the original spectral representation method using moda l factorization with fifty modes.