The cable systems of cable-supported bridges can be designed in harp, fan, or modified fan arrangements. This work provides an aeroelastic analysis to address the problem of structural flutter in such bridges, which are becoming increasingly long. In doing this, it assumes that the structural behavior of the bridge under the influence of wind is linear, and shows that an eigenvalue problem needs to be solved. The task is to find the value of wind speed at which flutter starts taking place.

Cable-supported bridges with lengths of 800, 1,000, and 1,200 meters, and decks similar to that of the Great Belt Bridge in Denmark are evaluated. Results obtained using the most important modes for flutter analysis show that the bridges become stiffer as the main span becomes shorter, and the cable system is the fan configuration. However, results with 25 lower frequency vibration modes indicate the contrary. This is suspected to be due to the fact that flutter derivatives have not been considered in the analysis; hence, there is room for more research.