Suspension Bridge Vibrations: Computed and Measured

Measured frequencies of a suspension bridge were found to differ from those calculated by a wide margin. The discrepancies were found to be caused by sliding deck joints not sliding at small amplitudes, which affected the stiffness. When these and other minor effects were correctly modeled the agreement was excellent. Lateral-torsional coupled motion caused by a channel type cross-section was found to influence the position of the center of rotation, which has an effect on the aerodynamic behavior. Measured values of structural damping are given, and a comparison is made between approximate and exact methods of computing natural frequencies and mode shapes.