Control of wind-induced nonlinear oscillations in suspension bridges

In this paper, the along-wind response and across-wind response of the suspended cables and the bridge deck of a suspension bridge are studied. The mean wind direction is assumed to be perpendicular to the plane of the suspended cable. It is shown that the suspended cable, if constructed alone, gallops in the across-wind direction when the mean wind speed exceeds a critical wind speed. Similarly, the bridge deck if constructed alone will gallop when the wind speed exceeds a certain critical wind speed. The construction of a suspension bridge through coupling the bridge deck with the suspended cables via vertical hangers will increase the critical wind speed at which galloping occurs for the bridge. This paper discusses the means of further increasing the critical wind speed for a suspension bridge using a passive or active control mechanism.