The energy-based analytical method for evaluating the modal damping of cable structures is proposed and its potential is discussed. After developing the damping theory of cables, the damping characteristics of stay cables, with and without cable-cross ties, in cable-stayed bridges, is investigated by using experimentally measured damping data as well as byconducting the damping analysis. It is concluded that the proposed analytical method of damping evaluation is very useful, and some peculiarities in modal damping of cable systems are clearly shown with theoretical bases. The modal damping of cable-stayed bridges is finally studied to show the coupling mode dependency of modal-damping characteristics.
