An analytical approach to evaluate damping property of orthogonal cable networks

Cross-tie solution is becoming more popular for mitigating unfavorable cable vibrations on cable-stayed bridges. Connecting a vulnerable cable with its neighbours using cross-ties to form a cable network would not only enhance its in-plane stiffness, but also affect its damping property. While the majority of existing studies focused on the enhancement of the in-plane stiffness, of which the mechanisms are better understood now, the research on the damping effect remain scarce. However, an effective cross-tie design should consider both factors. An analytical model of a two-cable network consisting of two horizontally laid main cables interconnected by a transverse orthogonal rigid cross-tie will be proposed in the current paper to study the damping property of the system. The inherent structural damping of the two main cables will be considered in the formulation, and an equivalent modal damping of the cable network is proposed. The developed analytical model and approach will be applied to a number of two-cable networks with various configurations, and validated by independent finite element simulations. Based on the impact of cross-tie design on the in-plane stiffness and damping of the network, a range of optimum cross-tie position will be defined.