In-plane modal responses of two-cable networks considering cable bending stiffness effect

Abstract

Cross-tie solution has proven to be effective in mitigating cable vibrations on cable-stayed bridges. In the formed cable network, the consisting cables are divided into shorter segments by cross-ties and thus significantly reduced their effective length. While bending stiffness plays an important role in the behavior of shorter cables, its effect has not been considered in any existing cable network analytical models. To assess the impact of cable bending stiffness on the in-plane dynamic response of cable networks, in the current study, an existing analytical model of a two-cable network is refined by taking into account the cable bending stiffness in the formulation. A set of closed-form solutions are derived to clearly reveal the impact of cable bending stiffness on the modal response of two-cable networks having different configurations. The proposed analytical model is validated by numerical simulations and the modal analysis results are compared with those of the corresponding taut-cable networks. It is found that the cable bending stiffness would influence all the modes of a cable network by increasing their modal frequencies, with the stiffening effect on the high order global and local modes being more considerable. If neglected, an underestimation of network fundamental frequency up to 7.1% could occur. Further, the cable bending stiffness has more effect on local modes than global modes. Some local modes could evolve into global modes. Nevertheless, the modal order is not affected by the presence of cable bending stiffness.