Static Wind Load Effect Analysis Of Long-Span Half-Through Cfst Arch Bridge

This paper first sorts the basic theories of numerical wind tunnelz,then analyzes aerodynamic characteristics of truss arch ribs by CFD method.Taking a long-span half-through CFST arch bridge as the research object,the aerodynamic drag characteristics of the arch rib segments,static wind stability and the law of aerostatic instability are analyzed by ANSYS.The main results and conclusions obtained are as follows:(1)The two-dimensional simplified model of the CFST arch bridge is established by CFD method.Then the correctness of this model is verified by the wind tunnel test results.The effects of different wind angles of attack,Reynolds number effect on the three-component force coefficients and aerodynamic interference effect between the double arch ribs are concerned.The results show that it is feasible to calculate the aerodynamic drag coefficient of the arch rib by numerical wind tunnel and two-dimensional simplified model.There is aerodynamic interference effect between the double arch ribs.When checking the lateral static wind stability,the force of the downstream arch rib can be considered using the blocking coefficient of the upstream arch rib 0.53.(2)The numerical wind tunnel simulation of the Pingnan Third Bridge is carried out,and the variation law of the drag coefficient of the arch rib along the bridge span direction is obtained.Based on the ANSYS platform,the static gust response of the Pingnan Third Bridge at the bridge stage and the construction stage are analyzed.The results show that material nonlinearity,geometric nonlinearity,wind speed,number of cross braces and wave wind cable arrangement have different effects on the static wind stability of long-span CFST arch bridges.The critical wind speed of static instability is 75m/s,and the instability of arch rib is the spatial bending and torsion coupling instability mainly caused by lateral deformation.