Abstract：Aimed at the calculation for the equivalent rigidity of the truss stiffening girder in the aeroelastic model design of long-span suspension bridge with truss stiffening girder, in this paper, Aizhai bridge, which is a super-long –span suspension bridge across deep valley with single span, is taking as an example for investigation. In order to get the accurate equivalent rigidity characters of the truss-stiffening girder, finite element models of the truss-stiffening girder with different length were built, and then the theoretical formula for calculating the deformation of cantilever girder under concentrate force was adopted to evaluate the equivalent rigidity value of the truss girder. The analysis result indicted that the influence of local stress due to different load style disappeared at the section which is about two times section width distance from the load location, and the length of selected section model should be long enough to make the model have characters of single girder in both of vertical and cross directions. Furthermore, equivalent spring was designed to simulate the constraint effect of the tower and side main cable, based on the analysis of finite element model, equivalent aeroelastic model of single girder with rigid tower was built which dynamic characters showed good agreement with the prototype.
2009, Vol. 28 
