Study On Measures Against Vibration And Aerodynamic Stability Of Steel-concrete Composite Edge Girder

In three decades, China became the largest country in the bridge construction. The steel-concrete composite edge girder is widely used in long-span cable-stayed bridge, for its convenient to construction, short construction period, reasonable structure stress, high comprehensive benefits and all. However, due to its bluff body shape, it is susceptible to wind-induced vibration problems like vortex-induced vibration and flutter. Therefore, it cannot meet the design requirements when this type of bridges is built in coastal regions. therefore, it need rational measures of vibration-suppression to improve its aerodynamic performance. The measures of vibration-suppression include, aerodynamic measure and structural measures. Aerodynamic measurement suppress vibration by changing the flow around the bridge, and it is widely used in design for its simple structure, economy and practicality. However, different section needed different measurement due to its different aerodynamic performance. Currently, there are many types of aerodynamic measurement, such like deflector, fairing, Stabilizer, etc. Researcher get suitable aerodynamic measure through wind tunnel test. However, aerodynamic measurement for edge girder section is also lack of systematic study, trying to find out suitable measurement often spent lots of time. Therefore, the study of aerodynamic stability and aerodynamic measurement of edge girder has important significance and engineering value. This paper investigate the influence of depth-width ratio, shape and aerodynamic measure to aerodynamic stability of edge girder with a series of sectional model wind tunnel tests. The main contents of this thesis are as follows:1、 The research methods, influence factors and aerodynamic measures were presented and discussed.2、The influence of depth-width ratio and shape on aerodynamic stability of edge girder is investigated. Based on some actual bridge section, three sectional model of rib-slab girder and edge box girder with different depth-width ratio are tested for its VIV and critical wind speed.3、The effect of different aerodynamic measure on edge girder with different depth-width ratio is investigated. The wind tunnel test of different sectional model with airing, stabilizer and deflector was conducted for test effects of those aerodynamic measure.4、Numerical simulations of flow behaviors around stationary section model was conducted. The static aerodynamic coefficients, the Strouhal number and the vortex shedding frequency were obtained. To some extent, the vorticity result reveal the mechanism of VIV of test model.