Frequency and damping of hybrid cable networks with cross-ties and external dampers: Full-scale experiments.

This paper presents a full-scale experimental study on dynamics of hybrid cable networks composed of three real cables, a rigid cross-tie and three viscous-shear dampers. For comparison, an improved numerical model of cable networks considering cross-ties, dampers, and cross-tie pretension is also provided. The measured frequencies and mode shapes of the cable networks with different configurations and cross-tie locations are found in good agreement with corresponding theoretical predictions. The characteristics of damping variation with respect to cross-tie location and the layout observed from the experiments are generally consistent with the theoretical analysis, although there is a discrepancy between identified and computed values of damping. The experiments show that the cross-tie when located close to the dampers can lead to a reduction in modal damping of low-frequency modes. The dampers in the cable networks provide relatively large damping to global modes and modes dominated by vibrations of cable segments to which the damper is connected. Furthermore, when the cross-tie is installed far away from the external dampers, the cross-tie extended to the ground can effectively improve the system modal damping, as the length of the cable is reduced equivalently and the relative distance of the damper away from the closest anchor as compared to the cable length is increased. [ABSTRACT FROM AUTHOR]