Frequency domain dynamic analyses of freestanding bridge pylon under wind and waves using a copula model

Abstract With complex terrains and varied physical environments near bridge sites, it is challenging to include uncertainties for dynamic analyses of sea-crossing bridges. In this paper, an efficient frequency domain method for the dynamic analysis of a freestanding bridge pylon is proposed with a copula model to consider the correlation between wind and waves. Firstly, the data of wind and waves are obtained by field measurements. A best copula model is chosen to simulate the joint probability distribution. After calculating the fluctuating wind field and the random wave filed, the wind and the wave loadings are obtained. To reduce the calculation cost for dynamic analyses, the harmonic response analysis is introduced to solve the structural response spectrum by integrating the transfer function between the environmental load and the structural response. A sea-crossing railway bridge pylon located in the sea-crossing region is presented to demonstrate the effectiveness of the proposed method. Finally, the influence of seasons, load directions, and water depths on the displacement response of the top pylon is further discussed. The response spectrum analysis illustrates the influence mechanism of the correlated wind and wave on bridge pylon.