Influence of Central Buckles on the Modal Characteristics of Long-Span Suspension Bridge

Abstract

Finite element analysis (FEA) and a dynamic test are employed to investigate the influence of central buckles on the modal characteristics of the Aizhai bridge. The FEA result shows that (1) the longitudinal floating frequency of the bridge can be significantly raised with central buckles; (2) the influence of central buckles on anti-symmetrical lateral bending frequencies is larger than that on symmetrical mode; and (3) rigid central buckles can raise the symmetric vibration modal frequencies of main cables, whereas the flexible central buckles nearly have no effect. Further testing on the dynamic behavior of the aero-elastic model of the Aizhai bridge is conducted. The result indicates that (1) the anti-symmetric lateral bending modal frequencies increase with the increasing stiffness of the central buckles; (2) central buckles have slight influence on the vertical modal frequencies; and (3) central buckles can enhance the entire stiffness and natural frequencies of suspension bridges, especially for anti-symmetric torsional and longitudinal vibration frequencies.