Aerodynamic Stability Of Cables With Lamps Of Cable-stayed Bridge

With the tourism developing and landscape needed,more and more lighting has been implemented on urban Bridges and the lamps installed on the cables of cable-stayed Bridges is one of the most widely used lighting schemes.However,the aerodynamic shape of the stay cables is changed by the installation of lamps on the stay cables,which may induce the windinduced vibration of the stay cables so the structural safety is danger than before.Based on the lighting project of one cable-stayed bridge,the wind-induced vibration and the aerodynamic force of the cable installed with lamps is studied in this thesis.The following works are mainly carried out:1.The current situation of development of long-span cable-stayed Bridges and the forms of lamps commonly used in bridge lighting projects at the present stage is introduced.Several wind-induced vibration situations of stay cables and the research status of wind-induced vibration of stay cables by scholars at home and abroad at the present stage is expounded.The necessity of this study is also explained.2.The commonly research methods used of bridge wind resistance at the present stage is introduced and the wind tunnel test method studying the cable installed with lamps is adopted.The static aerodynamic model test,dynamic segment model test and dynamic test under different wind dip Angle and wind deflection Angle are carried out.3.The basic principles of computational fluid dynamics and several turbulence models are introduced.The two-dimensional CFD numerical calculation model is established to calculate the three-component force coefficient,the galloping force coefficient and the St number.According to the Den Hartog criterion,whether the galloping of the stay cable will occur is observed.4.The three-dimensional numerical calculation model of stay cable is established to calculate the static three-component force coefficient,wind pressure coefficient and the vortex detachment form of the leeward side of the three-dimensional stay cable is also observed.The calculation results of the three-component force coefficient are compared to the twodimensional model and wind tunnel test,which verify the feasibility of the three-dimensional calculation model.The three-dimensional model of 100 mm diameter cable under different wind yawed angles is established and the three-component force coefficients are calculated and the vortex detachment of the leeward side of the stay cable is observed.The spectrum analysis is also carried out as a supplement to the wind tunnel test.5.FLUENT software is used to calculate the lift force received by the three-dimensional model at different wind speeds when the wind Angle is 20°.The displacement response of the stay cable is calculated when the lift force is applied to the ANSYS model.