Wind-rain-induced vibration of cable: An analytical model (1)

There have been many reports recently on excessive and unanticipated vibration of cables in cable-stayed bridges under the simultaneous occurrence of wind and rain. Correspondingly, many efforts have been made to avoid such large amplitude cable vibrations that often cause fatigue damage and corrosion to strands in surprisingly short periods. However, the mechanism of wind-rain-induced cable vibration is still not clear and the analytical solution is being actively sought for the design of cables against such a vibration. This paper thus presents a preliminary theoretical study aiming to provide an analytical solution to the problem and to explain some phenomena observed from field measurements and wind-rain tunnel tests. The proposed analytical model takes into account the effect of mean wind speed on the position of upper rivulet and the influence of moving upper rivulet on cable vibration. The analytical model is then verified through the comparison with the simulated wind tunnel tests for cables with moving rivulet or fixed artificial rivulet. It turns out that the analytical model can capture main features of wind-rain- induced cable vibration. The comparative studies also shed light on the mechanism of wind-rain-induced cable vibration.