The Research Of Aerodynamic Performance Of Slender Steel Truss Stiffened Girder Of Long Span Suspension Bridge

Abstract:Due to its advantages of long span and low cost, slender steel truss stiffened girder of long span suspension bridge has become an effective tool to cross the river, valley or reservoir area. This kind of bridge has slender deck, short truss height, very light and soft, and its damping is small, and it is very sensitive to the action of wind. So, wind resistance performance of this bridge is one of the key factors that affect bridge design programs, and the study on aerodynamic performance of slender steel truss stiffened girder of long span suspension bridge has great significance.By means of numerical simulation and wind tunnel test, this paper studies the aerodynamic properties and flutter stability of Shideng suspension bridge. The main work is as follows:1. This paper analyzes the influence of different real area ratio and spacing ratio on the wind resistance coefficient of main truss components. Besides, the influence that H type component and rectangular cross-section component make on the static three-component force coefficients of main truss is studied.2.3D numerical models of suspension bridge’s construction state and finished bridge state are constructed, and the impacts of wind speed, wind attack angle and main truss spacing ratio on the three component coefficients of truss beam are analyzed.3. An experimental study on static three-component force coefficients of Shideng suspension bridge’s main girder section model is conducted. Main girder section models of scale of1:15for suspension bridge’s construction state and finished bridge state are constructed, and static three-component force coefficients of truss beam under different wind speeds and different wind attack angles are analyzed. And the results of numerical simulation and wind tunnel test are compared and analyzed.4. Numerical models for suspension bridge’s main girder in finished bridge state are constructed, and its flutter derivatives are calculated. Critical flutter velocity is obtained according to critical flutter velocity calculation method deduced by Scanlan. Besides, the effects of spacing ratio on the flutter stability of main beam are analyzed.