Multimode cable vibration control using a viscous‐shear damper: Case studies on the Sutong Bridge

Abstract

Summary This study investigates multimode damping effects of a long cable attached with a viscous‐shear damper (VSD). A typical VSD comprises a casing box containing viscous medium and shearing plates with parts submerged in the medium. It dissipates vibration energy through shear deformation of the viscous medium. The VSD is low‐cost and invulnerable to leakage or increasing joint play and hence requires low maintenance effort. For studying its damping effects on long cables, three VSDs were designed respectively for three long cables of the Sutong Bridge, a cable‐stayed bridge with a main span of 1,088 m, and then tested in laboratory under forced sinusoidal displacements with various frequencies and amplitudes. Their dynamic behaviors were found to be accurately modeled using a viscous damper with intrinsic stiffness, while the viscous and stiffness coefficients depend on frequency and amplitude. The VSDs were subsequently attached to the cables respectively, and modal damping ratios of in‐plane modes of each cable without dampers and with the VSD were measured by free‐decay testing. The measurements obtained for most in‐plane modes with frequency less than 3 Hz show that the VSD provides satisfactory multimode damping effects with efficiency factors between 30% and 50% as compared to an ideal viscous damper and the damping decreases slightly for higher modes. The measurements are also found consistent with the results of complex modal analysis of a shallow cable with a Kelvin–Voigt damper considering frequency‐ and amplitude‐dependent damper properties. Particularly, analytical prediction using the damper properties tested under small deformation amplitude provides the lower bound of the damping effect.

Prototype Test and Numerical Analysis of a Shallow Cable with Novel Viscous Inertial Damper

“…Considering the displacement compatibility of equation (18) and the force equilibrium of equation (20) at the VID location, the wave number equation can be obtained as Considering λ 2 � 0, the third term of equation ( 21) is also zero, which is consistent with the wave number equation of the taut cable [38][39][40].…”

“…Passive viscous dampers solve the vibration problem of cables to some extent, but the installation location restricts the damper's damping effect. e installation location does not exceed 5% of the cable length [17,18], so the additional damping ratio provided may be limited. Additionally, parameters such as the sag, bending stiffness, damper support stiffness, internal stiffness, and the coupled vibration between the cable and the beam will reduce the damping effect [15,19].…”

In‐plane dynamic behaviors of two‐cable networks with a pretensioned cross‐tie

“…Figure 2 shows the parameters and χ 2 varying with respect to the cross‐tie location μ ∈ [0, 1], respectively, for and . The sag‐extensibility parameter of the cable without any cross‐ties is chosen to be because it is realistic for large‐span cable‐stayed bridges like the Sutong Bridge 12.47 . Figure 2a shows that when is positive, is positive, and vice versa, as above defined.…”

“…[1][2][3][4] Vibrations can reduce the fatigue life of the cables and threaten the safety of the whole bridge structure and can also cause a deep anxiety in the public. To mitigate cable vibrations, many countermeasures have been used in practice, including aerodynamic treatment of cable surfaces, 5-7 installing cable dampers, 1,[8][9][10][11][12] and the use of cross-ties to connect neighboring cables. 13,14 For stay cables of cable-stayed bridges, installing a damper near…”

Optimized negative stiffness damper with flexible support for stay cables

“…Various countermeasures, such as aerodynamic methods, 1–3 cross‐ties, 4–8 mechanical dampers, 9–16 and specific combinations of these 17–20 have been proposed to mitigate the damaging vibrations. Among these approaches, employing a damper exhibiting negative stiffness behavior has become a promising method owing to its cable vibration energy dissipation capacity.…”