Influence of central buckle on dynamic behavior and seismic response of long-span suspension bridge

In order to investigate the function of central buckles of the long-span suspension bridge under dynamic loads excitation, taking the Sidu River Bridge, a suspension bridge with steel truss stiffening girders, as an example, the spatial dynamic finite element models for the Bridge with three types of central buckles were established with ANSYS software. Self-vibration behavior analysis and 3-D nonlinear time history analysis for the Bridge under seismic excitation were carried out. Analytical results show as follows: The central buckle raises the antisymmetrical torsion stiffness and restricts the longitudinal floating characteristic of the suspension bridge, and enhances dynamic coupling effect of the girder-cable-tower; a pair of flexible central buckles is not advisable to be adopted for seismic design of the suspension bridge because it has adverse effect on longitudinal displacement and stress response of the stiffening girder; the rigid central buckle and three pairs of flexible central buckles have significant effect on restricting the longitudinal vibration amplitude of the stiffening girder, however, thus making seismic stress responses of the structure increase greatly. Therefore the use of the central buckle has ″merits and demerits″ from the angle of seismic design of the suspension bridge.