A vibration reduction device for a stay cable of a long-span bridge

Abstract

This utility model belongs to the field of vibration control technology and discloses a vibration damping device for cable-stayed bridges in long spans. A cable sleeve is fixed at a suitable position on the cable. One end of a lightweight, high-strength thin rope is connected to an anchor point on the bridge deck, and the other end is connected to one end of a sliding energy-dissipating cable. The sliding energy-dissipating cable wraps around the cable sleeve, and the other end of the cable is connected to a mass ring that can slide freely around the cable. When the cable vibrates, the sliding energy-dissipating cable slides back and forth on the sleeve to dissipate energy, suppressing cable vibration. Compared with traditional viscous dampers and their associated large support devices, this utility model has a simple structure, is lightweight and compact, has low cost, flexible installation location, is easy to replace, highly adaptable, and does not affect the aesthetics of the bridge deck. Multiple devices can be arranged on the cable to effectively control multi-mode vibration. This utility model can also efficiently control wind-induced lateral vibration of the bridge's vertical suspension cables and horizontally split conductors.

Description

Technical Field

[0001] This utility model belongs to the field of bridge cable vibration control technology, and relates to a vibration reduction device for cable stays of long-span bridges. Background Technology

[0002] Long-span bridge stay cables are characterized by a large slenderness ratio, light weight, and low damping. They are prone to large vibrations under the influence of wind, rain, and vehicles, and in severe cases, they may even collide with each other, which has an adverse effect on the durability of the bridge stay cables and structure, as well as the safety of vehicle operation.

[0003] Viscous dampers are widely used in vibration control of cable-stayed bridges, offering good vibration reduction and cost-effectiveness for shorter cables. However, for ultra-long cables, high-order multimodal vibrations may occur. The damper support points may be located high above the bridge deck, and the damping effect is only relatively good for certain modes of vibration. To ensure sufficient support stiffness, the cost of support materials and installation increases significantly, and the aesthetics of the bridge deck are severely affected. Furthermore, viscous dampers may face problems such as aging or leakage of the damping medium, leading to failure and seriously impacting vibration control effectiveness.

[0004] Connecting cables between adjacent stay cables can improve the overall stiffness of the cable system and reduce the amplitude of individual cables to some extent. However, this can also cause multiple cables to vibrate simultaneously, which, although the amplitude may be small, can severely impact the travel experience for passengers. Furthermore, this method only increases the interconnection between stay cables and does not effectively dissipate vibration energy. To prevent the connecting cables from breaking, they need to have sufficient strength, typically with a diameter of several centimeters, which affects the bridge's aesthetics and increases costs.

[0005] Based on the above, this utility model proposes a vibration reduction device for cable-stayed bridges with many functions and advantages. Utility Model Content

[0006] This utility model proposes a simple, lightweight, easy-to-install, easy-to-replace, low-cost, stable and efficient vibration reduction device for cable-stayed bridges in long spans.

[0007] The technical solution of this utility model:

[0008] A vibration damping device for a long-span bridge cable-stayed structure includes a lightweight, high-strength thin rope 1, a bridge deck anchor point 2, a sliding energy-dissipating cable 3, a cable sleeve 4, a guide member 5, and a mass ring 6. The lower end of the lightweight, high-strength thin rope 1 is connected to the bridge deck anchor point 2 located on the main girder 7, and the upper end is connected to one end of the sliding energy-dissipating cable 3. The sliding energy-dissipating cable 3 is wrapped around the cable sleeve 4, which is tightened onto the cable-stayed structure 8. The lightweight, high-strength thin rope 1 is perpendicular to the cable-stayed structure 8. The guide member 5 is fixed to the cable sleeve 4, and the other end of the sliding energy-dissipating cable 3, after being turned by the guide member 5, is connected to the mass ring 6 that is looped around the cable-stayed structure 8.

[0009] The cable-stayed vibration damping device for this long-span bridge is installed at multiple locations between the vertical suspenders or between the horizontal split conductors of the bridge.

[0010] The sliding energy dissipation cable 3 and the cable sleeve 4 are made of materials with a resistance coefficient of 0.1-0.3;

[0011] The sliding energy-dissipating cable 3 is wrapped around the cable sleeve 4 with more than one turn and less than two turns.

[0012] Multiple sets of long-span bridge cable-stayed vibration damping devices are installed between one cable-stayed cable 8 and the bridge deck to better control multi-mode vibration.

[0013] The beneficial effects of this utility model are as follows: (1) This utility model has a simple structure, is lightweight and small, does not affect the aesthetics of the bridge deck, and is easy to install and replace, with low construction and maintenance costs; (2) This utility model is directly connected between the cable and the bridge deck by a lightweight and high-strength thin rope, without the need for a heavy support, and the installation position is flexible and adaptable. The appropriate installation height can be selected according to the vibration characteristics of the cable; (3) This utility model is economical and practical, and the number of installations is unlimited. One or more can be arranged on the cable according to the length of the cable and the vibration amplitude requirements, which can effectively control the multi-mode vibration of the cable and has good robustness; (4) This utility model can also be installed between the vertical suspension cables of the bridge or between the horizontal split conductors to efficiently control wind-induced lateral vibration. Attached Figure Description

[0014] Figure 1 This is an overall schematic diagram of a cable-stayed vibration reduction device for long-span bridges proposed in this utility model;

[0015] In the diagram: 1 Lightweight high-strength thin rope, 2 Bridge deck anchor point, 3 Sliding energy dissipation cable, 4 Cable sleeve, 5 Guide component, 6 Mass ring, 7 Main beam, 8 Stay cable. Detailed Implementation

[0016] The specific embodiments of this utility model are described in detail below with reference to the technical solution and accompanying drawings.

[0017] like Figure 1 As shown, a cable-stayed vibration reduction device for a long-span bridge includes a lightweight, high-strength thin rope 1, a bridge deck anchor point 2, a sliding energy-dissipating cable 3, a cable sleeve 4, a guide component 5, and a mass ring 6.

[0018] The vibration damping device for the cable-stayed bridge is installed between the bridge deck and the cable-stayed cable 8. A cable sleeve 4 is fixed at a suitable position on the cable-stayed cable 8. One end of a lightweight, high-strength thin rope 1 is connected to an anchor point set on the bridge deck (or cable-stayed cable 8), and the other end is connected to one end of a sliding energy-dissipating cable 3. The sliding energy-dissipating cable 3 is wrapped around the cable sleeve 4 at least once and at least twice. The other end of the sliding energy-dissipating cable 3 is connected to a mass ring 6 that is looped around the cable-stayed cable 8 and can slide freely.

[0019] Taking the device controlling the vibration of a single stay cable 8 as an example, the lower end of the lightweight, high-strength thin rope 1 is connected to the bridge deck anchor point 2 located on the main beam 7, and the upper end is connected to one end of the sliding energy dissipation cable 3. The sliding energy dissipation cable 3 is wrapped around the cable sleeve 4, and the cable sleeve 4 is tightened on the stay cable 8. The lightweight, high-strength thin rope 1 is basically perpendicular to the stay cable 8. The guide 5 is fixed on the cable sleeve 4, and the other end of the sliding energy dissipation cable 3 is connected to the mass ring 6 after passing through the guide 5. The mass ring 6 is wrapped around the stay cable 8.

[0020] In a static state, the middle section of the sliding energy dissipation cable 3 tightly wraps around the cable sleeve 4, and each end of the sliding energy dissipation cable 3 has a certain length of unwound section to ensure that the sliding energy dissipation cable 3 has sufficient sliding length when the stay cable 8 vibrates; in the vertical plane, the sliding energy dissipation cable 3 is as perpendicular as possible to the stay cable 8, thereby ensuring the highest energy dissipation efficiency.

[0021] When the stay cable 8 is stationary or experiencing slight vibration, the lightweight, high-strength thin rope 1 of the above-mentioned device is under tension, and the sliding energy-dissipating cable 3 is tightly bound around the cable sleeve 4. When the main beam 7 and the stay cable 8 move away from each other from a state of static equilibrium, the lightweight, high-strength thin rope 1 is further tightened. When the tension exceeds the resistance between the sliding energy-dissipating cable 3 and the cable sleeve 4, the sliding energy-dissipating cable 3 and the cable sleeve 4 slide relative to each other, generating sliding energy dissipation, which does negative work for the stay cable 8, suppressing the vibration of the stay cable 8. At the same time, the mass ring 6 is lifted. When the main beam 7 and the stay cable 8 move closer to each other, the lightweight, high-strength thin rope 1 relaxes, the cable tension decreases, and the sliding energy-dissipating cable 3 slides back to its original position around the cable sleeve under the gravity of the mass ring 6 (at this time, the sliding force is very small). This process consumes almost no energy, thus ensuring that the sliding energy-dissipating cable 3 is tightened again to dissipate energy in the next vibration cycle. The materials used for the sliding energy dissipation cable 3 and the cable sleeve 4 can provide a moderate (e.g., 0.1-0.3) drag coefficient, ultimately requiring only a small mass ring 6, which is both economical and does not affect the aesthetics.

[0022] In the structure described above, the sliding force between the sliding energy dissipation cable 3 and the cable sleeve 4 depends on the drag coefficient, the envelope angle of the sliding energy dissipation cable 3, and the tension on the slack side (the side with less tension) of the sliding energy dissipation cable 3. When the drag coefficient is large enough or the number of cable wrapping turns is large enough, the sliding energy dissipation cable 3 will lock up. If a suitable drag coefficient (such as 0.1-0.3) and a smaller number of wrapping turns (such as 2 turns) are used, this problem will not occur. When the stay cable 8 moves downward, the lightweight, high-strength thin rope 1 connected to the main beam 7 slackens, and the sliding energy-dissipating cable 3 on that side also slackens accordingly, becoming a loose side. The tension decreases significantly (basically equal to the weight of the lightweight, high-strength thin rope 1). At this time, the sliding energy-dissipating cable 3 wrapped around the cable sleeve 4 spontaneously stretches, and its tension decreases significantly. If a suitable resistance coefficient and fewer winding turns are used, the static friction between the sliding energy-dissipating cable 3 and the cable sleeve 4 is greatly reduced, and the mass ring 6 with a certain mass can completely drive the cable back to its original position. The lightweight, high-strength thin rope 1 has sufficient strength and stiffness.

[0023] The anchor points 2 on the bridge deck or cable-stayed cable 8 have sufficient strength, stiffness and durability;

[0024] The aforementioned sliding energy-dissipating cable 3 has sufficient strength, stiffness, and wear resistance;

[0025] The cable clamp 4 has sufficient strength, rigidity and wear resistance;

[0026] The guide member 5 is fixed at a suitable position on the cable sleeve 4 to adjust the tension direction of the sliding energy dissipation cable 3, and has sufficient strength, rigidity and durability.

[0027] The mass ring 6 is a ring structure that can slide freely up and down on the cable 8. The mass ring 6 can be flexibly designed according to the required energy dissipation resistance.

[0028] The above description is merely a preferred embodiment of this utility model and should not be considered as any limitation thereof. Any equivalent changes, modifications, or improvements made by those skilled in the art to the above embodiments when utilizing the technical solution of this utility model should be considered as falling within the protection scope of this utility model.

Claims

1. A vibration damping device for a stay cable of a long span bridge, characterized by, The cable-stayed vibration reduction device for the long-span bridge includes a lightweight high-strength thin rope (1), a bridge deck anchor point (2), a sliding energy-dissipating cable (3), a cable sleeve (4), a guide (5), and a mass ring (6). The lower end of the lightweight high-strength thin rope (1) is connected to the bridge deck anchor point (2), and the upper end is connected to one end of the sliding energy-dissipating cable (3). The sliding energy-dissipating cable (3) is wrapped around the cable sleeve (4), and the cable sleeve (4) is tightened on the cable (8). The lightweight high-strength thin rope (1) is set perpendicular to the cable (8). The guide (5) is fixed on the cable sleeve (4), and the other end of the sliding energy-dissipating cable (3) is turned by the guide (5) and connected to the mass ring (6) wrapped around the cable (8). The sliding energy dissipation cable (3) and the cable sleeve (4) are made of materials with a resistance coefficient of 0.1-0.3; The sliding energy dissipation cable (3) is wrapped around the cable sleeve (4) for more than 1 turn and less than 2 turns.

2. The large span bridge stay cable vibration reduction device according to claim 1, characterized in that, The cable-stayed vibration damping device for this long-span bridge is installed at multiple locations between the vertical suspenders or between the horizontal split conductors of the bridge.

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