Full Scale Experimental Evaluation for Cable Dampers

One of the key techniques for building long span cable-stayed bridge is the mitigation of stay cable vibration. Mechanical dampers are widely used to mitigate in-plane and out-plane vibrations of long stay cables. In this study, two types of oil dampers were tested by a full scale model. Two types of tests were carried out. Test 1 is the damper performance test for evaluating the damping performance of dampers when they were installed on stay cables. The tested dampers were connected to the cable model via a full scale damper socket; and for one cable there were 2 dampers installed in perpendicular. The test results showed that both types of dampers have nonlinear damping characteristics. Test 2 is the durability test for evaluating the deterioration of dampers. Both two types of dampers were tested by using a fatigue testing machine until 4 million cycles with a frequency of 4 Hz and amplitude of 1 mm. The performance tests of damper were also carried out after every 1 million cycles. According to the durability test results, a formula for performance deterioration of damper was established to predict the lifetime of damper. The test results were very helpful to design the dampers and their sockets for long cable-stayed bridges.