Experimental verification of the effectiveness of elastic cross-ties in suppressing wake-induced vibrations of staggered stay cables

In the present study, two pairs of cable models were specially designed and tested to reproduce wake induced vibration (WIV) of stay cables in a wind tunnel. The interaction between multi-modes and the flexibility of the stay cables were considered. The downwind cables experienced large vibrations beyond a critical wind speed, similar to classical galloping. The response characteristics in terms of vibration amplitude, frequency, and trajectory were investigated in detail. The observed tendency of the increase in vibration frequency with increasing wind speed is adequately consistent with the previous studies. Finally, elastic cross-ties were vertically installed and connected two neighboring cable models in an attempt to suppress WIV. The wind tunnel tests demonstrated that the elastic cross-tie modified the single-mode dominated WIV into a type of chaotic multi-mode vibration and successfully reduced the vibration amplitude by ∼74%. The reason why the elastic cross-tie suppressed RWIV was qualitatively discussed. The scale ratio of the cross-tie stiffness was derived for engineers. Consequently, for the first time, the elastic cross-tie was proposed and verified to be effective to suppress the WIV of stay cables.