Experimental Investigation on Vortex-Induced Vibration Mitigation of Stay Cables in Long-Span Bridges Equipped with Damped Crossties

Abstract

In this study, based on the high energy-dissipating capacity of viscoelastic dampers with shearing deformation, damped stay cable crossties were proposed to mitigate the vortex-induced vibration (VIV) of stay cables in long-span bridges. Viscoelastic dampers were installed at the connection points of cable crossties to dissipate the kinetic energy of stay cable vibration. Three stay cable models incorporating different numbers of damped crossties were set up in a wind tunnel. Experimental investigations on the control efficacy of the proposed damped stay cable crossties and their parametric influence on the mitigation of the VIV of stay cables were conducted. Numbers of the damped crossties connected with a target main stay cable at different locations were experimentally studied, when the first three modal VIV of three stay cable models were excited respectively. On the basis of the test results, the oscillation behavior of the VIV of the three stay cable models with and without control was ascertained. The experimental results indicated that the proposed damped stay cable crossties can significantly reduce the VIV of stay cables by increasing the stiffness and damping of the cables, and can enhance the modal frequency and the onset wind velocity of the VIV of stay cables due to the increased stiffness.