Vibration Control Of Stay Cables Research Articles

The use of Classical Rolling Pendulum Bearings (CRPB) for vibration control of stay-cables

Cables are efficient structural elements that are used in cable-stayed bridges, suspension bridges and other cable structures. A significant problem which arose from the praxis is the cables’ rain-wind induced vibrations as these cables are subjected to environmental excitations. Rain-wind induced stay-cable vibrations may occur at different cable eigenfrequencies. Large amplitude Rain-Wind-Induced-Vibrations (RWIV) of stay cables are a challenging problem in the design of cable-stayed bridges. Several methods, including aerodynamic or structural means, have been investigated in order to control the vibrations of bridge’s stay-cables. The present research focuses on the effectiveness of a movable anchorage system with a Classical Rolling Pendulum Bearing (CRPB) device. An analytical model of cable-damper system is developed based on the taut string representation of the cable. The gathered integral-differential equations are solved through the use of the Lagrange transformation. . Finally, a case study with realistic geometrical parameters is also presented to establish the validity of the proposed system.

Feasibility Study of Passive Electromagnetic Dampers for Vibration Control of Stay Cables

Effective vibration control technology for stay cables is extremely critical to safe operations of cable-stayed bridges. This paper focuses on a new cable vibration control technology and introduces an electromagnetic damper being tested for its electrical performance. Control performance of a model cable attached with a passive electromagnetic damper was investigated in the laboratory. The test results show that modal damping ratios of the cable in the first four modes can be improved significantly with the electromagnetic damper. As such, advantages and feasibilities of this new cable vibration controlling system are finally demonstrated.

Isolation System for Vibration Control of Stay Cables

Rain-wind induced cable vibration can cause serious problems in cable-stayed bridges. Externally attached dampers have been used to provide an effective means to suppress the vibration of relatively short stay cables. For very long stay cables, however, such damper systems are rendered ineffective, as the dampers need be attached near the end of the cables for aesthetic reasons. This paper investigates a new stay-cable isolation system to mitigate the cable vibration. The proposed isolation system, which consists of a laminated rubber bearing and an internal damper, may be installed inside of the cable anchorage. A simple analytical model of the cable-damper system is developed first based on the taut string representation of the cable. The response of a cable with the proposed isolation system is obtained and then compared to those of the cable with and without an external passive damper. The proposed stay-cable isolation system is shown to perform better than the optimal passive viscous damper, thereby demonstrating its applicability in large cable-stayed bridges.

Vibration Control of Stay Cables of the Shandong Binzhou Yellow River Highway Bridge Using Magnetorheological Fluid Dampers

The Shandong Binzhou Yellow River Highway Bridge is a three-tower, cable-stayed bridge in Shandong Province, China. Because the stay cables are prone to vibration, 40 magnetorheological (MR) fluid dampers were attached to the 20 longest cables of this bridge to suppress possible vibration. An innovative control algorithm for active and semiactive control of mass-distributed dynamic systems, e.g., stay cables, was proposed. The frequencies and modal damping ratios of the unimpeded tested cable were identified through an ambient vibration test and free vibration tests, respectively. Subsequently, a series of field tests were carried out to investigate the control efficacy of the free cable vibrations achieved by semiactive MR dampers, “Passive-off” MR dampers and “Passive-on” MR dampers. The first three modal damping ratios of the cable incorporated with the MR dampers were also identified from the in situ experiments. The field experiment results indicated that the semiactive MR dampers can provide significantly greater supplemental damping for the cable than either the Passive-off or the Passive-on MR dampers because of the pseudonegative stiffness generated by the semiactive MR dampers.

Papers in This Issue

The July 2007 issue of the Journal of Bridge Engineering begins with a paper on vibration of stay cables. In “Vibration Control of Stay Cables of Shandong Binzhou Yellow River Highway Bridge Using Magnetorheological Fluid Dampers,” Li, Liu, Li, Guan, and Ou describe the use of an innovative control algorithm for active and semiactive control of mass-distributed dynamic systems. The longest cables of the Shandong Binzhou Yellow River Highway Bridge were stabilized to suppress vibration using 40 magnetorheological fluid dampers. Field tests were carried out and determined that the semiactive magnetorheological dampers can provide greater supplemental damping than “passive-on” or “passive-off” dampers. Next are three papers on bridge desks. In the first one by Oh, Lew, and Choi, the issue of safety of deck slabs and the resulting frequent repair and strengthening is investigated. In “Realistic Assessment for Safety and Service Life of Reinforced Concrete Decks in Girder Bridges,” the development of a realistic assessment system that can estimate the safety and remaining service life of concrete bridge decks is presented. By determining a realistic and accurate assessment of the bridge deck, the cost of repairs can be eliminated and the loss of use to the public during possibly unnecessary repairs can be prevented. The proposed method uses an assessment of corrosion along with analysis of flexture, shear, and fatigue. The second bridge deck paper is titled “Low-Cycle Fatigue Testing of High-Performance Concrete Bonded Overlay-Bridge Deck Slab Systems” and is authored by Issa, Alhassan, and Shabila. This paper describes a field performance evaluation of a full-scale prototype bridge deck using plain and fibrous latex– modified concrete and microsilica concrete overlays. The study found that this overlay provided good results. “Stiffness and Strength of Metal Bridge Deck Forms,” by Egilmez, Helwig, Jetann, and Lowery, is the final paper on bridge decks. This paper presents the results of the first phase of research investigating the bracing behavior of metal bridge deck forms. While the bracing effects of these forms are used in building construction, due to connection details, the bracing effects are normally not considered when these forms are used in bridge construction. Shear diaphragm tests were conducted to determine the shear stiffness and strength of the forms. The experimental results on the diaphragms indicate the potential for the bracing of steel bridge girders using metal deck forms. The fifth paper in this issue of the Journal of Bridge Engineering is about bridge expansion joints. Malla, Shaw, Shrestha, and Brijmohan in “Development and Laboratory Analysis of Silicone Foam Sealant for Bridge Expansion Joints,” present the results of the development of an elastomeric foam-type joint sealant for use in small-movement bridge expansion joints. The paper presents the results of an investigation using both foam and solid sealants. “Deck-Mounted Steel Post Barrier System,” by Reid, Faller, and Hascall, presents the results of an evaluation of an existing mountable safety barrier system on a fiber-reinforced plastic