Research On Static Wind Response Of Suspension Bridges With Steel-Concrete Composite Deck

In recent years, with the continues development of economy and the frequent communication among countries, more and more cross-sea bridges need to be built. Due to the advantages of suspension bridge with long-span, it becomes the first choice of many cross-sea bridge projects. With the span of the suspension bridges is more and more big, the problem of static wind stability becomes increasingly prominent. According to the test results of wind tunnel tests at home and abroad, the instable critical wind velocity of long-span suspension bridge in static may be less than in dynamics. Currently, the stiffening girder of long-span suspension bridge generally use flat steel box girder, rarely use steel-concrete composite beams, the steel-concrete composite beams can increase the critical instability static wind velocity compares with the flat steel box girder suspension bridge, it is necessary to study the static wind response of suspension bridge with steel-concrete composite beam.The static coefficients are calculated by using the FLUENT of ANS YS software in this paper. Considering the structural geometry nonlinearity and static wind load nonlinearity, based on the ANSYS and APDL of large general software of finite element, writes the corresponding analysis program through the combination of wind load increment and both internal and external iteration, which is used for tracking the whole process of steel-concrete composite beams suspension static wind response, and verified its accuracy and stability through examples. Then using Maputo bridge as the engineering background, analyzed the whole process of its static wind instability applying the procedure, and uncovered the characteristics of the static wind instability. Then carried out the calculate analysis about the influence that different initial wind attack angles% components of aerodynamic force coefficient、the static wind load on main cable and sling、nonlinear factors and different span on the static wind response of this bridge. Explored the aerostatic instability mechanism of the suspension bridge with steel-concrete composite beams. Finally, we carried out the comparative analysis of the static wind response of the suspension bridge when stiffening girder is the steel-concrete composite beams and the flat steel box girder.This study shows that static wind response can be accurately analyzed in consideration of structural geometry nonlinearity and static wind load nonlinearity. The interaction between static wind load and bridge structure leads to the static wind instability. There is an intimate connection between aerodynamic force coefficients of stiffening girder cross section and aerostatic instable patter of suspension bridge. The aerostatic instable critical wind velocity is higher when stiffening girder is steel-concrete composite beams than is flat steel box girder. This has an important realistic meaning in the future application of steel-concrete composite beams in suspension bridge.