Studies on Effecting Factors of Damper Efficiency for Long Stay Cables

One of the most effective measures for vibration mitigation of long stay cables of large span cable-stayed bridges is using mechanical dampers. In the conventional design theory for cable damper, it is assumed that the damper is linear and without any stiffness, and the cable's ends are fixed. However, actual mechanical dampers usually have nonlinear characteristics, and in addition when the span of cable-stayed bridge becomes large and the structure becomes more flexible, the effects of bridge girder and tower vibration on the cable damper performance may not be ignorable. To improve the efficiency of cable dampers, effecting factors should be taken into account when designing dampers. In this paper, the effects of damper nonlinearity, damper stiffness and dynamic interaction between cables and bridge girder were investigated theoretically and experimentally. The test results showed that these effecting factors reduced the effectiveness of cable dampers, and the proposed theoretical modal can be used for damper design.