Research Of Wind-rain Induced Vibration On The Stayed Cables For The Cable-stayed Bridges

Today, because of the merits such as reasonable structures, compact shape, long span, artistic contour and the better stability of aerodynamic force, so the cable-stayed bridge is extremely rapid.The stayed cable is the essential component, by way of the most important of the bearing structure, almost supports the all dead load and live load. But because of its smaller quality, rigidity and damping, it is easy arise from the transverse vibration under the wind or supporting end. Especially under the climatic conditions of the medium wind speed and the medium intensity rain, the cable easily arise the wind-rain induced vibration, this large amplitude vibration often causes fatigue damage and corrosion to strands, arouses bridge deck vibration and threatens safe traffic. At home and abroad, experters have developed some theories and experimental study to the wind-rain induced vibration. Because this phenomenon has some relations with the interaction of solid, fluid and wind, its research is extremely complex and its vibration mechanism and the characteristic are not completely clear at present. Researching the wind-rain vibration mechanism, we can thoroughly know its vibration characteristic and various parameters influence rule, which will provide the scientific basis for the cable vibration reduction, and it's very important to the safe operation of the cable-stayed bridge.Basing on the general commentary of the research about the wind-rain induced vibration both here and abroad, this article establishes the cable movement equation to the small distortion cable and uses the method of finite difference to carry on the computation of the cable vibration response and inherent characteristic of stayed cable. It detailedly introduces the field observation and analysis of Dong Ting Lake Bridge. And it carries on the statistical analysis to each influence factors of the wind field, applying all kinds of the numerical value figure to reveal the relation between the primary influencing factors of the wind-rain induced vibration; Making mode analysis and time-frequency analysis to the observation data, the model distribution and transfer are obtained, some beneficial conclusions are arrived at. Using the non-linear principle of least squares to carry on the fitting of the cable velocity and displacement, finally we can achieve the size and transformation of the wind equivalent load. We can evaluate the cable force change during the wind-rain induced vibration, and draw on the new conclusion.