Comparison of probabilistic multivariate wind environment between typhoon and synoptic climate and its propagation in buffeting response for a long-span bridge

Buffeting of bridges is turbulence-induced vibration affecting the serviceability and may lead to structural fatigue. The first step in evaluating the buffeting response is to determine the turbulence parameters in the wind environment based on field measurements. For long-span bridges in coastal regions, both typhoon and synoptic wind climates attack the bridge sites. In this study, the multiparameter dependence of turbulence parameters under typhoon and synoptic wind climates is established employing the isoprobabilistic transformation method. A surrogate model based on polynomial chaos expansion is then constructed from the transformed isoprobabilistic model to estimate the vertical, lateral and torsional buffeting responses at multiple locations on the bridge. Compared to synoptic winds, typhoons exhibit higher turbulence intensity and greater dispersion in turbulence parameters. The turbulence spectrum of typhoons shows higher energy in the lower frequency range. The multivariable turbulence parameters are modeled using the Gaussian Copula. For bridge buffeting, typhoons cause higher response amplitudes even at the same wind speed as synoptic winds. Additionally, the vertical and torsional responses exhibit nonlinear dependencies, particularly at high wind speeds.