ABSTRACT

In order to research the influence of wind-wave-current coupling on the structural safety of the sea-crossing cable-stayed bridge under construction, the influence law of wind-wave-current coupling on the structural displacement response and internal force response of the cable-stayed bridge under construction is analyzed. The research results show that the dynamic response of the cantilever girder end in the most unfavorable construction state of the cable-stayed bridge has exceeded the comfort limit, and measures should be taken to control it. The displacement and acceleration dynamic response of the main girder are dominated by different structural vibration modes. It is recommended to adopt multi-frequency vibration reduction device to control.

INTRODUCTION

Compared to bridges built inland, bridges built across the sea are exposed to harsher environments, such as typhoons, waves, earthquakes, currents, and other highly destructive natural disasters (Wei, 2020). The coupling between strong winds, huge waves and rapids and their dynamic coupling with the bridge structure occur simultaneously. For large bridges across the sea, as the span diameter increases, the structural stiffness and damping of the bridge becomes smaller and smaller, and the coupling of wind and wave currents will excite the structure to produce significant dynamic effects. In particular, the bridge structure under unfavorable construction conditions is very sensitive to environmental dynamic loads. Under the coupling of wind, wave and current, the bridge structure may undergo wave resonance and Large chattering, which poses a threat to the safety and comfort of the construction environment. Therefore, it is very necessary to study the vibration phenomenon of long-span bridge structure under the coupling of wind, wave and current during construction. Dai (2020) carried out a numerical study on the dynamic response of a 4.6 km long straight and side-anchored floating pontoon bridge under the action of waves. The research results showed that under the condition of non-uniform and short wave crest, the influence of wave coherence and correlation at different locations is very small, and the wave coherence and correlation can be ignored in the wave load design of similar floating bridge. Cheng (2018) investigated the effects of uniform and non-uniform wave loads on the floating bridge. Ti (2019) investigated the stochastic response of a span cable-stayed bridge under nonlinear wave action and concluded that higher-order waves could potentially excite higher-order modes of the bridge, thereby increasing the bridge dynamic response. Xu (2019) established a VIV identification model based on the observation data of wind field vibration parameters of a cross-sea suspension bridge for three years, which can be used to warn the occurrence of bridge vortex vibration with a recognition rate of 89%. Zhou (2018) investigates the effect of strong winds on the structural vibration response and modal parameter changes of a seaward cable-stayed bridge based on the health monitoring data of a seaward cable-stayed bridge, where strong winds play a dominant role in the lateral vibration of the main girders of a large span bridge compared with traffic loads. Fenerci (2017) compared the measured buffeting response and the calculated buffeting response of Hardanger Bridge, and concluded that the wind field change should be considered in the buffeting response analysis of suspension bridge. Although the current research on bridge vibration under the coupling of wind, wave and current is rarely reported in the literature, the above research on bridge vibration under the action of wind and wave alone provides a useful reference for the study of bridge vibration under the coupling of wind, wave and current.

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