Dynamic analyses of long-span cable-stayed and suspension cooperative system bridge under combined actions of wind and regular wave loads

Abstract

This paper presents the dynamic analyses of long-span cable-stayed and suspension cooperative system bridge under combined actions of wind and regular wave loads. First, the wind loads acting on the bridge deck are calculated based on the aerodynamic force coefficients which were obtained in the wind tunnel and wave flume tests. Then, the wind loads acting on the bridge towers, piers and suspension cables are calculated based on the aerodynamic force coefficients which are simulated in FLUENT software. Besides, the regular wave loads acting on the composite foundations are simulated in FLOW-3D software. Finally, the dynamic responses of the bridge subjected to the combined actions of wind and regular wave loads are calculated in the Mechanical APDL module of ANSYS 17.0 software. The results indicate that the root mean square (RMS) values rather than the mean values of the time histories of the aerodynamic force coefficients obtained in the wind tunnel and wave flume tests should be selected to calculate the wind loads acting on the deck to accurately evaluate the dynamic responses of the sea-crossing bridge. The maximum RMS values of the displacement responses of the deck midspan and 5# tower top increase with the increase of the regular wave heights for the wind-wave cases, which are larger than those for the wind-only case, respectively. In general, the linear superposition of the dynamic responses under the actions of wind-only and wave-only is a conservative choice compared to the consideration of the combined actions of wind and regular wave loads. The displacement spectrums of the deck midspan and 5# tower top, and the lateral base shear and lateral base bending moment spectrums of 5# tower are analyzed to reveal the contribution mechanism of the wind loads, regular wave loads and natural frequencies of the bridge.