Vibration Mitigation of Suspension Bridge Suspender Cables Using a Ring-Shaped Tuned Liquid Damper

The suspender cable is one of the most vulnerable components in suspension bridges. Vibration of the suspender cables will induce fatigue damage, and large vibrations of these cables under extreme weather can be a threat to traffic safety. Therefore, it is imperative to develop effective methods to mitigate such vibration. In this article, a new approach of equipping the ring-shaped tuned liquid damper (RSTLD) to mitigate the vibration of suspender cables is presented. The Xinghai Bay Cross-Sea Bridge was selected as the field experimental and numerical research object to validate the proposed method. The feasibility and the design method for the RSTLD were validated through a numerical model of a suspender cable in this bridge. The performance of the RSTLD was further examined through an in-field experiment conducted on a suspender cable with a length of 61.55 m. Two RSTLD designs with different containers and liquids were considered, respectively, and the response of the symmetric suspender cable without the damper on the other cable plane was collected for comparison between the controlled and noncontrolled cases. The experimental results show that when the liquid was water and the mass ratio was 3%, the variance of acceleration and maximum acceleration were reduced by 50 and 20–30% with the RSTLD, respectively. The vibration-mitigation effect will increase with the adoption of a greater liquid viscous damping ratio or a greater mass ratio. The mitigation effect in experiments was found to be close to that in the simulation. Both the experimental and numerical results show that the RSTLD can effectively reduce the vibration of the suspension bridge suspender cable. The proposed RSTLD has equivalently good vibration-mitigation ability in all excitation directions, and it has positive effects in terms of service safety and extending the service life of the suspender cable.