Analysis of factors influencing galloping on the straddle sling damping ratio of long-span suspension bridges

The definition of galloping on straddle sling damping ratio of long-span suspension bridges and its influencing factors analysis are the key problems encountered in the design, and at the moment, the sling damping ratio of practical engineering significance in sling two-dimensional fluid-structure interaction is uncertain. To take advantage of the two-dimensional fluid-structure coupling calculation of wind vibration characteristics of sling in practical engineering, in which, the stiffness and damping ration of the sling section is important. In order to study the damping characteristics of the sling section, free damped vibration and finite element method were used to analyze the influence of the sling damping ratio when sling initial tension, length, diameter, wind speed, constraints and sling position changes. The conclusions are drawn as follows: when the initial tension of sling is increasing, its damping ratio will increase; when the diameter and length of sling are increasing, its damping ratio will decrease. The damping ratio of sling is affected by wind speed. Comparing with the two ends of hinge constraint, the two ends of fixed constraint will be more beneficial to increase the damping ratio of sling. The damping ratio in the middle of sling is the smallest. From the middle to the end, the damping ratio of sling is gradually increasing. Therefore, calculating sling Fludi-Solid Coupling, the value of sling damping ratio differs depending on sling initial tension, length, diameter, wind speed, constraints and sling position.