| Recently, as the span of the cable-stayed bridge increasing, the stay cablewhich is one of the most important components in cable-stayed bridge becomeslonger and flexible. Due to the small rigidity, small mass and relatively lowdamping, the cables are susceptiblely evoked various vibration. The large vibrationwould cause the cable to be fatigued and damaged or even destroyed, which will notonly increase the maintenance costs but also effect the normal service function ofthe bridge. So the long span stay cable’s vibration control is a hot research spot inthe the bridge wind engineering fields. The cross-ties measure is one of theeffective measures to mitigate the vibration, especially it’s irreplaceable for largespan cables’ vibration mitigation. But studies have found that the cross ties have avery small contribution to the cable net. The effect on cable’s vibration reductionfor cross-ties measure could be improved significantly by adding damped-cross-ties.In this paper, the dynamic characteristics of the cable net installed withdampers has been investigated, and the impact on vibration reduction of cross-tiesmeasure was studied. Firstly, the impact on the dynamic characteristics of the staycable with different number of cross ties was investigated. Secondly, a kind of cablenet damper was designed with the shear energy dissipation principle of theviscoelastic materials. And the damping effect on the cable net intalled with thedampers was analyzed and proved that the installation of dampers in the cable netwas effective control for wind vibration response of the cable. Lastly, the optimalarrangement of the dampers in the cable net was investigated, with the method ofusing the equivalent stiffness and damping of the viscoelastic damper model. Thenwe found that it would make a greater contribution to the cable net modal dampingratio, if the damper was decentralized as much as possible and arranged on the largedeformation of each low order mode of the cable net. |
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