Aerodynamic Oscillations in Suspension Bridges

Following the failure in 1940 of the Tacoma Narrows suspension bridge by wind-driven oscillations, the need for developing in advance adequate data concerning wind speeds at which such oscillations occur became apparent. Numerous studies and experiments were undertaken on the subject, the present paper dealing with a symmetrical suspension bridge having two towers in which both sidespan and tower effects are considered. A modification is given to include the effects of roadbed “slats,” and a method is outlined for obtaining flutter speeds from roadbed section models which may fit into standard wind tunnels. The theory is applied to the Tacoma Narrows Bridge.