Sliding self-balancing damping cable vibration reduction device

Abstract

The application provides a sliding self-balancing damping cable vibration damping device, which comprises a bridge tower, a main beam, a main cable, a longitudinal beam, a plurality of sliding sleeves and sliding blocks; one end of the longitudinal beam is fixedly connected with the bridge tower; a plurality of sliding sleeves are arranged on the main beam and arranged along the axial direction of the main beam, and the longitudinal beam is supported by the plurality of sliding sleeves; a sliding groove is arranged on the top surface of the longitudinal beam and arranged along the longitudinal direction of the main beam; a sliding block is arranged in the sliding groove, and the sliding block is connected with the sliding groove through a reset spring and a damper, and the axis of the reset spring and the damper is parallel to the axis of the sliding groove; the upper end of the main cable is connected with the bridge tower, the lower end of the main cable is connected with the sliding block, and the main cable is in a straightened state. The application has the advantages of simple structure, no influence of the expansion and deformation of the main beam on the internal force and configuration of the damping cable, no reset spring required for the auxiliary cable, reduced production cost, convenient installation, no sealing and high stress in the sliding structure during the expansion and deformation of the main beam, simple manufacturing, good durability and convenient maintenance.

Description

Technical Field

[0001] This invention belongs to the field of suspension bridge vibration reduction technology, specifically relating to a sliding self-balancing damping cable vibration reduction device. Background Technology

[0002] Long-span suspension bridges may experience large-amplitude vibrations such as vortex-induced vibrations under strong winds. These large-amplitude vibrations can easily lead to fatigue damage of the bridge and also cause traffic accidents.

[0003] Existing vibration reduction methods for long-span bridges mainly employ tuned mass damping. The principle of tuned mass damping involves connecting a mass block to the main beam via springs and dampers. By rationally designing the mass block's mass, spring stiffness, and damper parameters, a tuned mass damper (TMD) is formed. Figure 1 As shown. Figure 1 In the equation, m is the mass of the mass block, k is the spring stiffness, c is the damping of the damper, M is the mass of the main structure, k1 is the stiffness of the main structure, c1 is the damping of the main structure, F is the dynamic part of the excitation load such as wind and fluid on the structure, F0 is the amplitude of the external excitation, ω is the frequency of the external excitation, and t is the time.

[0004] When a bridge experiences significant vibration, the resonance principle, specifically the frequency of the TMD (Transient Damping) mechanism, is utilized. The TMD (Transient Dynamic Discharge Machining) vibrates at the same frequency as the bridge, causing it to vibrate significantly. The inertial force of the TMD balances the external excitation, thus suppressing structural vibration. However, the damping principle of the TMD dictates that it can only dampen a single frequency of the bridge. When the frequency of the TMD deviates from the structural vibration frequency, the amplitude of the TMD decreases rapidly, leading to a rapid decline in its damping effect. Simultaneously, as the structural vibration frequency decreases, the inertial force decreases rapidly, potentially making it difficult to balance the external excitation. Long-span suspension bridges not only have extremely low fundamental frequencies but also experience multi-frequency vibrations; for example, the vortex-induced vibration of the Xihoumen Bridge (main span 1650m) has not been effectively controlled.

[0005] Vibration reduction using energy-dissipating dampers (including various fluid dampers, friction dampers, rubber dampers, metal dampers, eddy current dampers, etc.) is currently limited to tower-beam connections due to their small size. They are primarily used to protect against potential tower-beam collisions during strong earthquakes. However, for wind-induced vibrations such as vortex-induced vibrations of the main beam, which exhibit multi-order sinusoidal wave vibrations with very small relative displacements between the main beam and the bridge towers and wave crests far from the towers, the energy-dissipating dampers are ineffective. Therefore, energy-dissipating dampers cannot suppress wind-induced vibrations in long-span suspension bridges.

[0006] The utility model patent with patent number Zl201920120501.1, entitled "A Vibration-Reducing Damping Cable for Suspension Bridges," describes a composite damping cable installed between the bridge tower and the main girder, connected in series with a return spring and a damper. The damper dissipates energy to suppress the vertical vibration of the bridge. For many bridges currently under construction in China with main spans exceeding 2000m, the main girder expands and contracts by tens of centimeters daily due to diurnal and winter-summer temperature variations, resulting in a length change of nearly 1m between winter and summer. Using this suspension bridge vibration-reducing damping cable structure requires the return spring to deform at a rate greater than 0.5m, with the spring itself approaching 2m in length; similarly, the damper's stroke needs to be greater than 0.5m, with the damper itself also approaching 2m in length. The damper is a high-pressure sealing device; large-stroke dampers are expensive to manufacture, and the daily expansion and contraction of the damper with the bridge's expansion and contraction leads to rapid wear of the damper seals, necessitating frequent damper replacements. In addition, considering the large weight of the original design's return spring and damper, pulleys are needed to steer the main cable to avoid affecting its shape. Since the main cable generates a large bending stress during bending, steel bars or steel strands (5mm diameter single wire) cannot be used for the main cable. Only steel wire rope can be used as the main cable. The tensile stiffness of steel wire rope with the same unit length mass is only about 50% of that of steel bars or steel strands. In order to achieve the same main cable stiffness, the diameter of the steel wire rope must be increased.

[0007] Similarly, due to the large deformation of the main girder with temperature changes, in order to ensure that the main cable always remains in a straight state, the alignment and tension of the auxiliary cable must remain basically stable during the expansion and contraction of the main girder. Therefore, the auxiliary cable springs must have low stiffness and large deformation, requiring a length of several meters. Even with increased lengths of the main cable return spring, damper, and auxiliary cable springs, because the composite damper is a statically indeterminate mechanical system, the significant expansion and contraction deformation of the main girder still has a considerable impact on the alignment of the main cable, making it difficult to ensure that the main cable remains in a straight state and affecting the energy dissipation effect of the damping cable on the bridge's vibration reduction function. Summary of the Invention

[0008] To address the aforementioned technical problems, this invention provides a sliding self-balancing damping cable vibration reduction device that is simple in structure, low in cost, and free from problems such as sealing and high stress in its sliding structure. It is also easy to manufacture, durable, and easy to maintain.

[0009] The technical solution adopted in this invention is as follows: a sliding self-balancing damping cable vibration reduction device, comprising a bridge tower, a main beam, a main cable, a longitudinal beam, multiple sliding sleeves, and a slider; one end of the longitudinal beam is fixedly connected to the bridge tower; multiple sliding sleeves are provided on the main beam, and the multiple sliding sleeves are arranged along the axial direction of the main beam, and the longitudinal beam is supported by the multiple sliding sleeves; a sliding groove is provided on the top surface of the longitudinal beam, and the sliding groove is arranged along the longitudinal direction of the main beam; a slider is provided in the sliding groove, and the slider is connected to the sliding groove by a return spring and a damper, the axes of the return spring and the damper being parallel to the axis of the sliding groove; the upper end of the main cable is connected to the bridge tower, the lower end of the main cable is connected to the slider, and the main cable is in a taut state.

[0010] Furthermore, the longitudinal beam includes a connecting rod and a sliding beam, one end of the connecting rod and one end of the sliding beam are fixedly connected, and the other end of the connecting rod is fixedly connected to the bridge tower; a sliding groove is provided on the sliding beam.

[0011] Furthermore, it also includes secondary cables, which are located above the main cables. The two ends of the secondary cables are connected to the bridge towers and the sliding beams, respectively. The main cables and secondary cables are connected by multiple hangers.

[0012] Furthermore, a stop is provided at each end of the slide. The end of the slider facing the bridge tower is connected to the stop at the end of the slide facing the bridge tower by a return spring, and the other end of the slider is connected to another stop by a damper.

[0013] Furthermore, a stop is provided at one end of the slide, and the slider is connected to the stop via a return spring and a damper at the end facing the stop.

[0014] Compared with the prior art, the beneficial effects of the present invention are:

[0015] (1) The present invention has a simple structure. The expansion and contraction deformation of the main beam does not affect the internal force and configuration of the damping cable. The deformation of the return spring and the stroke of the damper only need to consider the vibration requirements of the main beam. For a suspension bridge with a main span of 2000m, the stroke of the return spring and the damper only needs to be 2-8cm. The secondary cable does not need a return spring, which reduces the production cost and makes installation convenient.

[0016] (2) During the expansion and contraction deformation of the main beam, the sliding structure of the present invention does not have problems such as sealing and high stress, which are difficult to solve. It is easy to manufacture, has good durability, and is easy to replace if damaged, and is convenient to maintain.

[0017] (3) The main cable of the present invention does not need to be bent. The main cable can be made of rods or steel strands. Compared with the main cable of the comparative damping cable, which can only be made of steel wire rope, the same amount of material has greater tensile stiffness. Also, since it does not need to be bent, the durability of the damping cable is greatly improved. Attached Figure Description

[0018] Figure 1This is a schematic diagram of the principle and structure of a tuned mass damper (TMD) in the prior art.

[0019] Figure 2 This is a structural diagram of the main span of an ultra-long span suspension bridge.

[0020] Figure 3 This is a structural diagram of the present invention.

[0021] Figure 4 yes Figure 3 Enlarged view of section I in the middle.

[0022] Figure 5 yes Figure 4 Sectional view of AA.

[0023] Figure 6 This is a diagram showing the relationship between the vibration displacement of the main beam and the displacement of the slider in this invention. Detailed Implementation

[0024] The present invention will now be further described with reference to the accompanying drawings.

[0025] like Figure 2 As shown, the main span structure of the super-long span suspension bridge includes main components such as bridge tower 2, main girder 5, main cable 3, and bridge suspenders 4. Considering the temperature difference between day and night and between winter and summer, the main girder 5 is disconnected at the junction of the tower and the girder, and an expansion joint 1 is installed between the main girder 5 and the tower and the girder to ensure smooth passage of vehicles.

[0026] like Figure 3 As shown, this invention includes a bridge tower 2, a main beam 5, a main cable 8, a secondary cable 10, multiple sliding sleeves 7, a longitudinal beam (including a connecting rod 6 and a sliding beam 17), and a slider 14. One end of the connecting rod 6 is fixedly connected to the bridge tower 2, and the other end is fixedly connected to the sliding beam 17. Multiple sliding sleeves 7 are provided on the main beam 5, arranged along the axial direction of the main beam 5. The connecting rod 6 and the sliding beam 17 are supported by the multiple sliding sleeves 7 after connection. The sliding sleeves ensure that the connecting rod 6, the sliding beam 17, and the main beam 5 can slide freely along the axial direction, while relative movement in other directions is prevented.

[0027] The sliding beam 17 has a groove 12 on its top surface, which is arranged along the longitudinal direction of the main beam. A stop block 11 and a stop block 16 are respectively provided at both ends of the groove 12; a slider 14 is provided inside the groove 12. The end of the slider 14 facing the bridge tower 2 is connected to the stop block 11 at the end of the groove 12 facing the bridge tower 2 via a return spring 13. The other end of the slider 14 is connected to the stop block 16 via a damper 15 (or alternatively, one end of the groove 12 has a stop block, and the end of the slider 14 facing the stop block is connected to the stop block via a return spring 13 and a damper 15). The axes of the return spring 13 and the damper 15 are parallel to the axis of the groove. The upper end of the main cable 8 is connected to the bridge tower 2, and the lower end of the main cable 8 is connected to the slider 14, keeping the main cable 8 in a taut state. The auxiliary cable 10 is located above the main cable 8, with one end connected to the bridge tower 2 and the other end connected to the stop block 16 on the sliding beam 17. The main cable 8 and the auxiliary cable 10 are connected by multiple hangers 9. To ensure the main cable 8 remains taut, both the main cable 8 and the auxiliary cable 10 are tensioned. To maximize the stiffness of the main cable 8, a suspender rod 9 connects the main cable and the auxiliary cable, and the force of the suspender rod eliminates the sag of the main cable. The auxiliary cable 10 has a large sag, allowing it to bear the tension of the suspender rod with relatively small tension.

[0028] The working principle of this invention is as follows:

[0029] In this invention, the tension of the main cable 8 is transmitted to the sliding beam 17 via the slider 14, the return spring 13, and the stop block 11. Similarly, the tension of the auxiliary cable 10 is transmitted to the sliding beam 17 via the stop block 16. The horizontal force on the sliding beam compresses the connecting rod 6, which is then transmitted to the bridge tower 2. The vertical force on the sliding beam 17 is balanced by the force exerted by the sliding sleeve 7. The sliding beam 17 has high bending stiffness, ensuring minimal bending deformation under bending moment. The connecting rod 6 is subjected to pressure transmitted by the sliding beam; to prevent instability, multiple sliding sleeves are installed between the connecting rod and the main beam.

[0030] When the main beam 5 does not experience vertical bending vibration, the connecting rod 6 and the sliding beam 17 are connected as a whole and fixedly connected to the bridge tower 2. Regardless of temperature rise or fall, the main beam 5 may elongate or shorten, or the expansion joint may contract or open. The connecting rod 6 and the sliding beam 17 will generate relative displacement with the main beam 5 through the sliding sleeve. This will not increase or decrease the axial pressure on the connecting rod 6 and the sliding beam 17, nor will it affect the length of the connecting rod 6 and the sliding beam 17. Similarly, it will not change the tension of the main and auxiliary cables of the damping cable.

[0031] like Figure 6 As shown, when the main beam 5 undergoes vertical bending vibration, it is assumed that the slider connecting the damping cable to the main cable will shift upwards. y Under the action of the return spring 13, the slider 14 moves to the upper right. When the stiffness of the main cable 8 is much greater than the stiffness of the return spring 13, the return spring 13 keeps the tension of the main cable 8 basically unchanged. Ignoring the change in the length of the main cable 8, and because... yThe length of the main cable 8 is very small compared to its length, and can be considered as the lower end AB of the main cable moving parallel to CD. The angle between the main cable 8 and the main beam 5 is... θ Then slider 14 moves horizontally to the right a distance d x = y ×sin θ× cos θ If slider 14 moves downwards... y Similarly, it can be seen that slider 14 moves horizontally to the left a distance d. x The slider 14 moves left and right, driving the damper 15 to dissipate energy and reduce vibration.

Claims

1. A sliding self-balancing damping cable vibration reduction device, characterized in that: The system includes a bridge tower, main beam, main cable, longitudinal beam, multiple sliding sleeves, and sliders. One end of the longitudinal beam is fixedly connected to the bridge tower. Multiple sliding sleeves are provided on the main beam, arranged along the axial direction of the main beam, and the longitudinal beam is supported by the multiple sliding sleeves. A sliding groove is provided on the top surface of the longitudinal beam, arranged along the longitudinal direction of the main beam. A slider is provided in the sliding groove, and the slider is connected to the sliding groove by a return spring and a damper, the axes of the return spring and the damper being parallel to the axis of the sliding groove. The upper end of the main cable is connected to the bridge tower, and the lower end of the main cable is connected to the slider, and the main cable is in a taut state. The longitudinal beam includes a connecting rod and a sliding beam. One end of the connecting rod is fixedly connected to one end of the sliding beam, and the other end of the connecting rod is fixedly connected to the bridge tower. A sliding groove is provided on the sliding beam. It also includes secondary cables, which are located above the main cables. The two ends of the secondary cables are connected to the bridge towers and the sliding beams, respectively. The main cables and secondary cables are connected by multiple hangers.

2. The sliding self-balancing damping cable vibration reduction device according to claim 1, characterized in that: Each end of the slide is provided with a stop block. The end of the slider facing the bridge tower is connected to the stop block at the end of the slide facing the bridge tower by a return spring. The other end of the slider is connected to another stop block by a damper.

3. The sliding self-balancing damping cable vibration reduction device according to claim 1, characterized in that: One end of the slide is equipped with a stop, and the end of the slider facing the stop is connected to the stop via a return spring and a damper.

Images