Study On Static Tri-component Coefficients Of High-speed Railway Typical Bridge Sections

With the rapid development of China’s railway transit, the coverage of high-speed railways is increasing and the railway, including some windy regions such as conyons, valleys and coastal areas. Since the bridge is one of the high-speed railway infrastructure, the study on its wind performance has drawn more and more attentions. Study on static tri-component coefficients of high-speed railway typical bridge section is the basis for wind resistant design. The wind tunnel test has the disadvantages of long test cycle and high cost. In recent years, the computational fluid dynamics (CFD) simulation technology provides a way which is relatively simple, fast, accurate and low-cost to get the static tri-component coefficients of bridges.This thesis reviews the development of CFD technology and introduces the corresponding numerical calculation principles first. Then the static tri-component coefficients of three typical high-speed railway bridge section (box-beam, T-beam, trough-beam) are studied by FLUENT software. Different turbulence models and Reynolds number are taken into account. The result are compared with those from wind tunnel tests to verify the reliability of the models.According to the characteristics of three typical bridge sections, the influence of section size on tri-component coefficients are further researched. The differences are analyzed by using the wind pressure cloud, wind speed cloud and surface pressure distribution. The results provide an important basis for the aerodynamic selection of bridge section.Finally, different vehicle arrangements on the bridge are considered. The influence of vehicle position on the tri-component coefficients is studied.The research shows that:the SST k-co turbulence model is more reasonable to study the static tri-component coefficients of the 32m box-beam. Reynolds number has little influence in this study. Under the case of small wind attack angle of -6° to 6°, the drag coefficient of T-beam is minimum, then follows by the box-beam, and that of trough-beam is the biggest. However, the lift and moment coefficients, the wind resistance performance of trough-beam is the best, then follows by the T-beam, and the box-beam is the worst. The effect of section size on the tri-component coefficients is significant. Different vehicle arrangement on the bridge will considerably influence the aerodynamic properties of the vehicle-bridge system.