The Pneumatic Selection Of π-section Based On The Numerical Simulation

With the development of China’s bridge construction, more and more long-span bridges appeared in front of people as a city landmark. During the process of construction, there are all sorts of unknown problems need bridge builders to solve. Especially the wind-induced vibration phenomenon during the construction or operation has gradually become the decisive factor for the construction of large span bridges. At present, the bridge engineer mainly use wind tunnel to test bridge wind resistance in the actual wind field and related issues. However, wind tunnel tests has a long cycle, high cost and some objective factors, like basic equipment demanding, especially in early wind tunnel experiment is not conducted ideally, repeating, time-consuming and labor costly. With the development of computational fluid dynamics and numerical wind tunnel, researchers gradually applied these new methods in bridge wind resistance studies. Based on the comparison with wind tunnel test, we propose the girder section design in the form of combination assembly type for the numerical simulation of the aerodynamic cross section selection. This will has great importance regardless of the individual or the late application guidance of wind tunnel test.In this paper, a π type main girder cable-stayed bridge as the background, in each girder segment model test force, vibration, on the basis of wind tunnel test, choose three kinds of pneumatic measure girder assembly combination, through numerical simulation the Static-third force coefficient, the main girder section wake characteristics analysis, and 2 d section of flutter critical wind speed value, etc., under the premise that do not need to calculate the dynamic characteristics of bridge sections pneumatic selection, selection of scheme can be used to solve in the process of the wind tunnel test possible bridge wind-induced vibration phenomenon, to finally determine the main girder cross-section form has important guiding significance. After simulation, the result is consistent with the wind tunnel test.In addition, the study found that the numerical simulation can be not only used to analyze different aerodynamic measures of flow characteristics of change, but also help to determine the expected effect size. This method can be used to guide the selection and design of pneumatic type section.