Wind-tunnel Study On Wind-rain Induced Vibration Load Characteristics Of Stay Cables

The cable on the cable-stayed bridge has the characteristics of light weight,large flexibility and small damping.Under the combined action of wind and rain,the cable is very prone to wind and rain vibration.The large amplitude of wind and rain vibration is very easy to cause serious harm to the cable and its ancillary facilities,such as reducing the service life of the cable,causing fatigue damage to the cable anchorage,damaging the anti-corrosion protective layer of the cable,damaging the damper,and even causing cable failure.In this paper,the variation of wind and rain vibration suppression parameters and the variation of wind and rain vibration suppression measures are studied as follows:(1)Wind tunnel tests were carried out in a closed recirculation wind tunnel by introducing the rivulet method.The wind load and structural acceleration were measured.The effects of wind speed,wind deflection angle,inclination angle and frequency on the wind vibration amplitude of cables were discussed;Comparing the wind rain vibration amplitudes of cables with different space attitudes,the most unfavorable working conditions of wind rain vibration are obtained,and the in-plane and out of plane motion trajectories of wind rain vibration of cables are discussed.(2)The displacement response of the cable is obtained by integrating the acceleration signal,and the variation law of the displacement in the time and frequency domains is analyzed.According to the amplitude of the cable,the most unfavorable working condition of the wind-rain vibration phenomenon of the cable in the test is obtained,and the in-plane and outof-plane motion trajectory of the cable’s wind-rain vibration under the most unfavorable working condition is discussed.(3)The wind pressure and vibration acceleration on the cable surface are measured synchronously by the self-designed synchronous data acquisition system,and the variation laws of wind pressure distribution and displacement are analyzed;The time-domain and frequency-domain characteristics of aerodynamic coefficients and displacements are studied.The phase relationship between aerodynamic coefficients and amplitudes during rain wind vibration is discussed.The correlation between aerodynamic coefficients and displacements in the wind speed range of rain wind vibration is analyzed.(4)The vibration suppression efficiency of wind rain vibration of cable by surface winding helix and increasing damping ratio is discussed,and the influence of surface winding helix on aerodynamic coefficient,average wind pressure coefficient and amplitude of cable is discussed;The effect of increasing damping ratio on wind rain vibration suppression of cable is analyzed,and the effectiveness of two vibration suppression measures is compared.