Analytical and Numerical Study of Deck-Stay Interaction in a Cable-Stayed Bridge in the Context of Field Observations

This paper addresses the mechanism of coupled deck-stay motions in cable-stayed bridges. Field observations of deck-stay interactions are summarized and an analytical model is developed to simulate such interactions. Using this model, a dynamic analysis of an example stay is conducted to illustrate the mechanism underlying the coupled motions. Three-dimensional finite-element models of a cable-stayed bridge are presented to confirm that coupling of deck-stay motions can occur in actual structures. A comparison between the results from the analytical and numerical models indicates that the proposed analytical model can reasonably explain the observed deck-stay interactions. In particular, it is shown that coupled motions are associated with the veering of natural frequency loci and mode localization and that the distributions of generalized masses between decks and cables are useful indexes for assessing the degree of coupling.