Experimental investigation on wake-induced vibrations of the hangers of suspension bridges based on three-dimensional elastic test model

Large amplitude wind-induced vibrations of the hangers have been observed on several suspension bridges, and the underlying mechanism is not clearly clarified until now. In this study, the mechanism of wake-induced vibration of the hanger was studied by using wind tunnel tests based on three-dimensional (3-D) elastic test model. First, a new method was proposed to design 3-D elastic test model to accurately simulate a long cable in wind tunnel with a limited height. Second, taking the No.2 hanger of the Xihoumen Bridge as the background, a 3-D elastic hanger model was designed and manufactured by using the new method, and a series of wind tunnel tests were carried out within the spatial region of 3 ≤ P ≤ 10 and 0°≤α ≤ 20° to obtain the wake-induced responses of the hanger. The results show that obvious vibrations of the downstream cable are observed under all wind velocities tested (3 ~ 14 m/s), and the unstable region of the downstream cable tends to increase with the increase of wind velocity. Third, the effects of the structural damping on the wake-induced vibrations of the hangers were studied in detail. The results show that the wake-induced cable vibration of the hangers is not totally mitigated even if the structural damping ratio is as high as 1.37%. Finally, the effectiveness of two kinds of countermeasures (helical wires and spacers) on the wake-induced vibrations of the hangers of suspension bridges was experimentallystudied. The results show that the helical wire can suppress the wake-induced vibration of the test case of P = 7, α = 5°, but have no effect for the test case of P = 3.5, α = 20°. It seems that the spacer is a reasonable countermeasure to mitigate the wake-induced vibrations of the hangers of suspension bridges.

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  • English

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  • Accession Number: 01768029
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Feb 20 2021 12:46AM