Targeted-Energy-Transfer devices for stay-cable vibration mitigation

Free vibrations of a taut-cable with an attached passive Targeted-Energy-Transfer (TET) device are investigated using an analytical formulation of the complex generalized eigenvalue problem. This problem is of considerable practical interest in the context of stay-cable vibration suppression in bridges, induced by wind, wind-rain and parametric excitation. The TET device was modelled as a dashpot with a viscous damper in parallel with a power-law elastic spring element; a linear elastic spring was also added between the dashpot and the deck. Two types of TET devices were analysed: a Linear TET and a Nonlinear TET. For both the devices a family of “universal design curves” was developed, by accounting the effect of the elastic stiffness and the flexibility of the support. To verify the adequacy of the universal curves and to evaluate the effectiveness of TET devices, numerical simulations were performed on a reference cable and subsequently extended to an existing stay, taken from the Fred Hartman Bridge (Houston, Texas, USA).