A large-span bridge vortex-induced vibration control device

Abstract

The present invention belongs to the technical field of vibration control, and proposes a vortex-induced vibration control device for long-span bridges. The vortex-induced vibration control device for long-span bridges includes components such as cables, slings, pulleys, counterweights, damping elements, and tension springs. Through parameter optimization design and reasonable layout, multi-order vortex-induced vibrations of long-span bridges can be controlled simultaneously without tuning. When the bridge undergoes vortex-induced vibration, relative displacements occur between the main girder and the cables, slings, and counterweights. The damping elements provide damping forces for the device, thereby effectively controlling the vortex-induced vibration of the bridge. The device is simple in design, light in weight, low in cost, high in efficiency, and good in durability. In addition to being applicable to multi-order vortex-induced vibration control, it also plays an inhibitory role in buffeting, flutter, and vibrations caused by vehicle loads.

Description

Technical Field

[0001] The invention belongs to the technical field of vibration control and relates to a vortex vibration control device for a long-span bridge. Background Art

[0002] Severe vortex vibrations on bridges affect driving comfort and safety, so they must be effectively controlled. Currently, tuned mass dampers (TMDs) are a common mechanical measure for vortex vibration control on long-span bridges. A single TMD can only control vortex vibrations of a specific frequency. However, under different wind speed conditions, bridges may experience multiple vortex vibrations of different orders and frequencies, and the relatively large amplitude areas are also different. Therefore, multiple sets of TMDs with different frequencies need to be configured in different areas. This not only significantly increases the cost of the equipment, but also adds additional load to the bridge. In addition, for low-frequency vortex vibrations (such as <0.2Hz) on long-span bridges, traditional TMDs cannot be directly applied due to the large static deformation of the springs, and inertial mass dampers must be used. However, the cost is relatively higher, the control efficiency is relatively lower, and there is no actual engineering application yet.

[0003] For example, on a long-span suspension bridge in Zhejiang Province, six vortex vibrations were observed at frequencies of 0.095 Hz, 0.133 Hz, 0.183 Hz, 0.230 Hz, 0.276 Hz, and 0.324 Hz, with a maximum amplitude of 24 cm (data from the publicly available foreign literature, "Vortex-induced vibration analysis of long-span bridges with twin-box decks under non-uniformly distributed turbulent winds"; Journal of Wind Engineering & Industrial Aerodynamics, 2018, Vol. 172, Q. Zhu, YL Xu, LD Zhu et al., pp. 31-41). Using a traditional TMD to control a single vortex vibration order would require hundreds of tons of physical mass and cost at least 10 million yuan. Traditional TMDs are incapable of controlling vortex vibrations with frequencies below 0.2 Hz. Controlling multiple vortex vibrations would be prohibitively expensive. Therefore, how to adopt more advanced technologies to achieve effective control of multi-order vortex vibration while significantly reducing costs and alleviating additional loads has become a technical problem that needs to be solved urgently for some large-span bridges.

[0004] To address these issues, the present invention proposes a vortex-vibration control device for long-span bridges. This device features low cost, simple construction, no complex tuning required, robustness, high efficiency, and the ability to simultaneously control multiple vortexes while also reducing the bridge's buffeting response and the dynamic response caused by traffic. Summary of the Invention

[0005] The specific invention content and its advantages are as follows: The device can control the multi-order vortex-induced vibration of long-span bridges without tuning, has high reliability and excellent durability, and effectively reduces the device cost and maintenance cost. It is an economical and efficient vortex-induced vibration control device for long-span bridges.

[0006] The technical solution of the present invention:

[0007] A vortex-induced vibration control device for long-span bridges, including a cable 1, a first sling 2, a hole protection bushing 3, a first pulley 4, a second sling 5, a counterweight 6, a damping element 7, a waterproof cover 8, a second pulley 9, a third pulley 10, and a tension spring 11.

[0008] If the cable 1 is located outside the main girder: The cable 1 is horizontally suspended along the longitudinal direction of the bridge, and its two ends are anchored at appropriate positions of components such as bridge towers or arch ribs; the upper ends of several first slings 2 are suspended at different cross-section positions of the cable 1, and the lower ends pass through the hole protection bushing 3 of the deck roof hole and are finally wound and fixed on the first pulley 4 installed inside the main girder; one end of the second sling 5 is wound and fixed on the first pulley 4 in the opposite direction to the first sling 2, and the other end suspends the counterweight 6; the damping element 7 is installed between the counterweight and the main girder to provide damping force for the device; the vertically telescopic waterproof cover 8 is sleeved outside the first sling 2, with the lower end adhesively fixed to the bridge deck and the upper end tightly fastened to the first sling 2. With the above structure, several discrete vertical loads are applied to the cable 1 through the several counterweights 6, second slings 5, first pulleys 4, and first slings 2 arranged along the longitudinal direction of the bridge, so that it has sufficient vertical stiffness. If the main girder of the bridge generates a vertical relative displacement relative to the cable 1 and the counterweight 6, the damping element 7 provides damping force for the main girder, thereby consuming energy to control the vortex-induced vibration.

[0009] If the cable 1 is placed inside the main girder: The vortex-induced vibration control device for long-span bridges does not require the hole protection bushing 3 and the waterproof cover 8, and also includes a second pulley 9, a third pulley 10, and a tension spring 11; the cable 1 is horizontally suspended along the longitudinal direction of the bridge, and its two ends are anchored at appropriate positions inside the main girder, and several second pulleys 9 are longitudinally arranged on the inner roof of the main girder to provide support for the cable 1; the upper ends of several first slings 2 are suspended at different cross-section positions of the cable 1, and the lower ends are wound around the third pulley 10 installed inside the main girder and are wound and fixed on the first pulley 4 after being guided by the third pulley 10; one end of the second sling 5 is wound and fixed on the first pulley 4 in the opposite direction to the first sling 2, and the other end suspends the counterweight 6; the subsequent working principle is similar to the case where the cable 1 is located outside the main girder. Since the vertical space of the main girder of long-span bridges is usually in the range of 3 - 5m, after the third pulley 10 guides the first sling 2 at different cross-section positions of the cable 1, several horizontally arranged tension springs 11 are used to provide sufficient vertical stiffness for the cable 1, and thus the first pulley 4, the second sling 5, and the counterweight 6 are no longer needed.

[0010] The cable 1 is usually made of various high-strength parallel steel wires, high-strength fiber materials, etc. The larger the material, size, quantity, cable area, material elastic modulus, and rise-span ratio, the better the effect, but the cost is usually higher. Therefore, the design should be reasonably optimized according to actual needs. The cable 1 can be arranged at the central position of the main girder transversely, or on both sides (torsional vortex-induced vibration can be controlled simultaneously). If it is outside the main girder, it should be ensured that it does not affect traffic. If it is inside the main girder, the number and position of the second pulleys 9 and the rise-span ratio of each span of the cable 1 need to be optimized according to the nature and order of the controlled vortex-induced vibration mode.

[0011] The first sling 2 can be made of high-strength fiber materials and installed at multiple cross-sections of the cable 1 along the longitudinal direction of the bridge as needed to meet the multi-order vortex-induced vibration control requirements, ensuring sufficient strength, stiffness, and durability. The material type, size, and quantity are not limited.

[0012] The hole protection bushing 3 is installed in the opening of the main girder top plate to disperse the possible local friction between the first sling 2 and the main girder top plate, thereby protecting both of them. It has sufficient strength, stiffness, and durability, and the material, size, and form are not limited.

[0013] The first pulley 4 ensures sufficient strength, stiffness, and durability and can adopt a coaxial different-diameter structure. The first sling 2 winds around the part with a smaller wheel diameter, and the second sling 5 winds around the part with a larger wheel diameter. Thus, under the condition of the same tension of the first sling 2 and the cable 1, the weight of the counterweight 6 can be significantly reduced, the cost can be reduced, and the relative displacement between the counterweight 6 and the main girder can be significantly increased, improving the vibration control efficiency.

[0014] The second sling 5 can be made of high-strength fiber materials, ensuring sufficient strength, stiffness, and durability. The material type, size, and quantity are not limited.

[0015] The counterweight 6 has no limit on the material type, size, and quantity. Materials such as water tanks, sand boxes, concrete, and steel blocks can be selected, and its quantity and mass are determined according to needs.

[0016] The type, quantity, and installation position of the damping element 7 are not limited. It has a long service life and good economy. For the case of setting the counterweight 6, it is recommended to be installed between the counterweight 6 and the main girder bottom plate. For the case of setting the tension spring 11, it is recommended to be installed between the cable 1 and the main girder bottom plate.

[0017] The waterproof cover 8 can be made of elastic materials such as waterproof rubber to ensure a reliable sealing structure between the first sling 2 and the bridge hole, preventing rainwater and dust from entering the hole protection bushing 3 and the inside of the main girder along the first sling 2. The waterproof cover 8 should have a certain elasticity and deformability to adapt to the relative displacement between the first sling 2 and the main girder. In extreme cases, if the relative displacement is too large, the upper end of the waterproof cover 8 can also slide up and down along the first sling 2.

[0018] The second pulley 9 should ensure sufficient strength, stiffness and durability. The material type, size and quantity are not limited. The cable 1 can be disconnected and fixed separately at the second pulley 9 or allowed to slide longitudinally continuously.

[0019] The third pulley 10 should ensure sufficient strength and stiffness. The material type and size are not limited.

[0020] The tension spring 11 should ensure sufficient tension. The material type, size and quantity are not limited. The stiffness should not be too large and sufficient tensile length (the implementation method is not limited) is required to ensure sufficient tension.

[0021] Without setting the first pulley 4 and the second sling 5, the first sling 2 can be directly connected to the counterweight 6 to also consume energy and suppress vibration, but in this case, a larger weight of the counterweight 6 is required.

[0022] Both schemes of placing the cable 1 inside and outside the main girder have their own advantages and disadvantages, and various factors need to be considered for comprehensive comparison and selection.

[0023] Two sets of this device are set on both sides of the main girder in the transverse direction of the bridge. By increasing the area of the cable 1, the mass of the counterweight 6, the damping force of the damping element 7, etc., greater resistance and higher damping ratio can be provided for the bridge, and the critical wind speed of the soft flutter mainly dominated by torsional vibration of the bridge can also be greatly increased, reducing its amplitude. This device also plays a beneficial role in controlling the buffeting of the bridge and the vibration of the bridge caused by the vehicle load.

[0024] Advantages of the present invention: (1) Lower construction cost and maintenance cost: It can control multi-order vortex-induced vibration, reducing the need for multiple tuning devices, thus significantly reducing the overall construction cost; (2) Unrestricted control frequency: The device has a simple design and does not require complex tuning. It is not restricted by the vortex-induced vibration frequency, breaking through the bottleneck problem that traditional TMD cannot be applied to low-frequency vortex-induced vibration control due to excessive static deformation of the spring; (3) Smaller additional load: For the case where the cable is placed outside the main girder, compared with the traditional TMD, the first pulley not only avoids the additional vertical load caused by the counterweight block but also can provide an upward vertical support for the bridge. Each counterweight block increases the stiffness of the cable and contributes to the control of vortex-induced vibration in each mode. Therefore, unlike traditional TMD, sufficient counterweights are not required to control vortex-induced vibration in each mode; for the case where the cable is placed inside the main girder, each counterweight block and / or tension spring increases the stiffness of the cable and provides the same vertical stiffness for the cable. The mass of the required tension spring is much smaller than that of the counterweight block. (4) It can control multiple vibrations: In addition to vortex-induced vibration control, the device can also effectively control buffeting, flutter, and vibrations caused by vehicle loads. Description of the Drawings

[0025] Figure 1 is a schematic diagram of a vortex-induced vibration control device for long-span bridges (the cable is located outside the main girder);

[0026] Figure 2 is a schematic diagram of a vortex-induced vibration control device for long-span bridges (the cable is located inside the main girder);

[0027] In the figure: 1 cable, 2 first sling, 3 hole protecting bushing, 4 first pulley, 5 second sling, 6 counterweight block, 7 damping element, 8 waterproof cover, 9 second pulley, 10 third pulley, 11 tension spring. Detailed Embodiments

[0028] The following combines the technical solutions and the drawings to describe in detail the specific embodiments of the present invention, but the embodiments of the present invention are not limited thereto.

[0029] As Figure 1 and 2As shown in the figure, a vortex-induced vibration control device for a long-span bridge is proposed, which includes a cable 1, a first sling 2, a hole liner 3, a first pulley 4, a second sling 5, a counterweight 6, a damping element 7, a waterproof cover 8, a second pulley 9, a third pulley 10, and a tension spring 11. If the cable 1 is located outside the main girder: First, one or more cables 1 are anchored at appropriate positions on the bridge at both ends, so that the cable 1 is horizontally suspended longitudinally along the bridge; several first slings 2 are suspended at different positions of the cable 1. After their lower ends pass through the hole liner 3 of the bridge deck top plate, they are wound around the first pulley 4 installed inside the main girder and fixed to it; the second sling 5 is wound around the first pulley 4 in the opposite direction to the first sling 2, one end is fixed to the first pulley, and the other end suspends the counterweight 6; the damping element 7 is installed between the counterweight 6 and the main girder; the vertically telescopic waterproof cover 8 is sleeved outside the first sling 2, with the lower end adhesively fixed to the bridge deck and the upper end tightly fastened to the first sling 2. With the above structure, the counterweight 6, the second sling 5, the first pulley 4, and the first sling 2 apply a vertical load to the cable 1, making it have sufficient vertical stiffness. When the main girder of the bridge has a vertical relative displacement relative to the cable 1 and the counterweight 6, the damping element 7 provides a damping force for the main girder, thereby consuming energy to control vortex-induced vibration. If the cable 1 is placed inside the main girder: The cable 1 is horizontally suspended longitudinally along the bridge, and its two ends are anchored at appropriate positions inside the main girder. Several second pulleys 9 are longitudinally arranged on the inner top plate of the main girder to support the cable 1; the upper ends of several first slings 2 are suspended at different cross-section positions of the cable 1, and the lower ends are wound around the third pulley 10 installed inside the main girder and are wound and fixed to the first pulley 4 after being guided by the third pulley 10; one end of the second sling 5 is wound around the first pulley 4 in the opposite direction to the first sling 2 and fixed, and the other end suspends the counterweight 6; after the third pulley 10 guides the first sling 2 at different cross-section positions of the cable 1, several horizontally arranged tension springs 11 are used to provide sufficient vertical stiffness for the cable 1, so that the first pulley 4, the second sling 5, and the counterweight 6 are no longer needed. If the first pulley 4 and the second sling 5 are not provided and the first sling 2 is directly connected to the counterweight 6, energy can also be consumed to suppress vibration. When the cable 1 is inside the main girder, if the first sling 2 is further removed and the counterweight 6 is directly placed on the cable 1, energy can also be consumed to suppress vibration. The specific selection method is determined according to actual conditions.

[0030] As described above, it is only a preferred embodiment of the present invention and does not impose any formal limitations on the present invention. Any equivalent changes, modifications, or evolutions made by those skilled in the art to the above examples using the technical solutions of the present invention still fall within the scope of the technical solutions of the present invention.

Claims

1. A large-span bridge vortex-induced vibration control device, characterized in that, The long-span bridge vortex-induced vibration control device includes a cable (1), a first sling (2), a hole protecting bushing (3), a first pulley (4), a second sling (5), a counterweight (6), a damping element (7) and a waterproof cover (8); If the cable (1) is located outside the bridge main girder: The cable (1) is horizontally suspended along the longitudinal direction of the bridge, and its two ends are anchored on the bridge tower or arch rib; The upper ends of several first slings (2) are suspended at different cross-section positions of the cable (1), and their lower ends pass through the holes in the bridge deck roof and the hole protecting bushing (3), and are wound and fixed on the first pulley (4) installed inside the bridge main girder; One end of the second sling (5) is wound and fixed on the first pulley (4) in the opposite direction to the first sling (2), and the other end suspends the counterweight (6); The damping element (7) is installed between the counterweight (6) and the bridge main girder to provide damping force for the long-span bridge vortex-induced vibration control device; The telescopable waterproof cover (8) is sleeved outside the first sling (2), its lower end is adhesively fixed to the bridge deck, and its upper end is tightly fastened to the first sling (2); With the above structure, several discrete vertical loads are applied to the cable (1) through several counterweights (6), second slings (5), first pulleys (4), and first slings (2) arranged along the longitudinal direction of the bridge, so that it has sufficient vertical stiffness; If the bridge main girder generates vertical relative displacement relative to the cable (1) and the counterweight (6), the damping element (7) provides damping force for the bridge main girder, thereby consuming energy to control vortex-induced vibration; If the cable (1) is placed inside the bridge main girder: The long-span bridge vortex-induced vibration control device does not require the hole protecting bushing (3) and the waterproof cover (8), and further includes a second pulley (9), a third pulley (10) and a tension spring (11); The cable (1) is horizontally suspended along the longitudinal direction of the bridge, and its two ends are anchored inside the main girder. Several second pulleys (9) are longitudinally arranged on the inner roof of the bridge main girder to support the cable (1); The upper ends of several first slings (2) are suspended at different cross-section positions of the cable (1), and their lower ends are wound around the third pulley (10) installed inside the bridge main girder, and are wound and fixed on the first pulley (4) after being guided by the third pulley (10); One end of the second sling (5) is wound and fixed on the first pulley (4) in the opposite direction to the first sling (2), and the other end suspends the counterweight (6); After the third pulley (10) at different cross-section positions of the cable (1) guides the first sling (2), several horizontally arranged tension springs (11) are used to provide sufficient vertical stiffness for the cable (1).

2. The long-span bridge vortex-induced vibration control device according to claim 1, wherein Without setting the first pulley (4) and the second sling (5), the first sling (2) is directly connected to the counterweight (6), and it can also consume energy and suppress vibration; When the cable (1) is inside the bridge main girder, the first sling (2) is further removed, and the counterweight (6) is directly placed on the cable (1), and it can also consume energy and suppress vibration.

3. The long-span bridge vortex-induced vibration control device according to claim 1, characterized in that The cable (1) is arranged at the transverse central position of the bridge main girder, and it is made of high-strength parallel steel wires and high-strength fiber materials.

4. The long-span bridge vortex-induced vibration control device according to claim 1, characterized in that, The first pulley (4) adopts a coaxial structure with different diameters.

5. The long-span bridge vortex-induced vibration control device according to claim 1, wherein Two sets of long-span bridge vortex-induced vibration control devices are arranged on both sides of the main girder in the transverse direction of the bridge, which can suppress torsional vortex-induced vibration and flutter.

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