Research On Flutter Derivatives Of Bridge Girder Sections By Numerical Simulation

With the increasing of span, flutter stability has become a very important factor in designing and constructing of suspension bridges. Particularly in the early phase of construction, the stiffness of structure is less than that of the final state, which makes flutter critical wind speed dropping drastically. Taking the Yangtze River Highway Bridge in Yangluo, Wuhan as example, kinematic equation is solved by using the simulation method based on computational fluid mechanics and the programming method based on state-space techniques respectively, at the same time, the flutter stability of erection phase and final state is discussed and some related conclusions are drawn in this paper. This paper mainly studies on the following two aspects:(1) With FLUENT, the computational fluid mechanics software, the dynamic mesh technology of CFD is used to calculate the flutter self-excited forces of segmental model in numerical simulation. The eight flutter derivatives and flutter critical wind speeds about main girder sections of Yangluo suspension bridge are identified by using the different stage forced-vibration method and compared with Theodorsen' s theoretical Solution and experimental values.(2) Based on state-space techniques, 3-D flutter kinematic equation is deduced, and then solving the equation by programming of which the validity was tested by Great Belt Bridge. Lastly, this paper calculated every flutter critical wend speed of the Yangluo suspension bridge in various construction stage.