Optimal design of transverse dampers incorporating inherent stiffness effects for stay cable vibration control: A case study with wire rope dampers

This paper aims to develop an optimal design method for dampers incorporating inherent stiffness effects for cable vibration control. An explicit solution incorporating the inherent stiffness effects of dampers was proposed to predict the modal damping ratio of a cable-damper system, including both low-mode and high-mode vibrations. The explicit solution is in good agreement with the numerical results. An optimization method was established to quickly determine the optimal design parameters of the damper, using the modal damping ratio of the cable as the optimization criterion. Wire rope dampers, proven promising in cable vibration control, were taken as a case study. Extensive cyclic loading tests were conducted in this study to investigate the influences of design (geometric) parameters on the damping performance of wire rope dampers. Experimental results indicated that the loop mean diameter and rope diameter have nonlinear effects on the damping performance, while loop number exhibits a linear effect. The response surface formulas were developed by using experimental data to describe the geometric influences of wire rope dampers. The developed design method was used to optimize the wire rope damper installed on the stay cable of the Sutong Yangtze River Bridge. A dual damper arrangement was found to be significantly superior to the existing damper arrangement, not only increasing the modal damping ratio but also reducing the damper cost. The optimization design was verified by the harmonic response analysis and sinusoidal load excitation analysis results.