Large-span bridge vortex vibration control device

Abstract

The invention belongs to the technical field of vibration control, and provides a large-span bridge vortex vibration control device. The large-span bridge vortex vibration control device comprises a cable, a sling, a pulley, a balancing weight, a damping element, an extension spring and other components, and multi-order vortex vibration of a large-span bridge can be controlled at the same time through parameter optimization design and reasonable arrangement without tuning. During vortex vibration of a bridge, the main beam moves relative to the cable, the sling and the balancing weight, and the damping element provides damping force for the device, so that vortex vibration of the bridge is effectively controlled. The device is simple in design, light in weight, low in manufacturing cost, high in efficiency and good in durability, is suitable for multi-order vortex vibration control, and also plays a role in inhibiting buffeting, flutter and vibration caused by traffic load.

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 vibration of bridges affects the comfort and safety of driving, so it must be effectively controlled. At present, tuned mass dampers (TMDs) are commonly used mechanical measures for vortex vibration control of large-span bridges. A single TMD can only control vortex vibration of a specific frequency. However, under different wind speed conditions, bridges may have multiple vortex vibrations of different orders and frequencies, and the relatively large amplitude areas are also different. Therefore, it is necessary to configure multiple sets of TMDs with different frequencies in different areas. This not only greatly increases the cost of the device, but also adds additional load to the bridge. In addition, for low-frequency (such as <0.2Hz) vortex vibration of large-span bridges, traditional TMDs cannot be directly applied due to the large static deformation of the spring, and inertial mass dampers must be used. However, the cost is relatively higher, and the control efficiency is relatively lower, and there is no actual engineering application yet.

[0003] For example, in a long-span suspension bridge in Zhejiang, six-order vortex vibrations of 0.095Hz, 0.133Hz, 0.183Hz, 0.230Hz, 0.276Hz and 0.324Hz were found in the actual bridge, with a maximum amplitude of 24cm (data from the public 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, etc., pp. 31-41). If a certain order of vortex vibration is controlled by traditional TMD, hundreds of tons of physical mass may be required, and the cost is not less than 10 million. For vortex vibration control with a frequency below 0.2Hz, traditional TMD is powerless. If multi-order vortex vibration is controlled, the cost can be imagined. Therefore, how to adopt more advanced technology 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 urgently solved for some large-span bridges.

[0004] In view of the above problems, the present invention proposes a vortex vibration control device for a large-span bridge. The device has low cost, simple structure, no need for complex tuning, good robustness, high efficiency, can control multiple-order vortex vibrations at the same time, and can also reduce the bridge buffeting response and the dynamic response caused by driving. Summary of the invention

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

[0006] The technical solution of the present invention:

[0007] A vortex vibration control device for a long-span bridge includes 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 beam: the cable 1 is suspended horizontally 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-sectional positions of the cable 1, and the lower ends pass through the hole protection bushings 3 in the bridge deck top plate, and finally are wound and fixed on the first pulley 4 installed inside the main beam; 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 beam to provide damping force for the device; the waterproof cover 8 that can be retracted up and down is sleeved on the outside of the first sling 2, the lower end is adhered and fixed to the bridge deck, and the upper end is tightly bound with 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 pulley 4, and first slings 2 arranged along the longitudinal direction of the bridge, so that it has sufficient vertical stiffness. If the main beam of the bridge produces vertical relative displacement relative to the cable 1 and the counterweight 6, the damping element 7 provides damping force for the main beam, thereby consuming energy to control vortex vibration.

[0009] If the cable 1 is placed inside the main beam: the vortex vibration control device for large-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 suspended horizontally along the longitudinal direction of the bridge, and its two ends are anchored at appropriate positions inside the main beam, and a number of second pulleys 9 are arranged longitudinally on the top plate inside the main beam to provide support for the cable 1; the upper ends of a number of first slings 2 are suspended at different cross-sectional positions of the cable 1, and the lower ends are wound around the third pulley 10 installed inside the main beam, and are guided by the third pulley 10 and then wound and fixed on the first pulley 4; 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 a counterweight 6 is suspended from the other end; the subsequent working principle is similar to the case where the cable 1 is placed outside the main beam. Since the vertical space of the main beam of a long-span bridge is usually in the range of 3-5m, after the third pulley 10 guides the first suspension cable 2 at different cross-sectional positions of the cable 1, a number of horizontally arranged tension springs 11 are used to provide sufficient vertical stiffness for the cable 1, thereby eliminating the need for the first pulley 4, the second suspension cable 5 and the counterweight 6.

[0010] The cable 1 is usually made of various types of high-strength parallel steel wires, high-strength fiber materials, etc. The larger the material, size, quantity, cable area, material elastic modulus, and span-to-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 in the transverse center of the main beam, or on both sides (torsion vortex vibration can be controlled at the same time). If it is outside the main beam, it should be ensured that it will not affect driving. If it is inside the main beam, it is necessary to optimize the design of the number and position of the second pulley 9 and the span-to-span ratio of each span of the cable 1 according to the control of the vortex vibration modal properties and order.

[0011] The first suspension cable 2 may be made of high-strength fiber material and may be installed at multiple sections of the cable 1 along the longitudinal direction of the bridge as needed to meet the requirements of multi-order vortex vibration control and ensure sufficient strength, rigidity 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 beam top plate to disperse the local friction force that may be exerted between the first sling 2 and the main beam top plate, thereby protecting both. It has sufficient strength, rigidity and durability, and the material, size and form are not limited.

[0013] The first pulley 4 ensures sufficient strength, rigidity and durability, and can adopt a coaxial different diameter structure. The first sling 2 is wound around the smaller wheel diameter part, and the second sling 5 is wound around the larger wheel diameter part. In this way, the weight of the counterweight 6 can be greatly reduced while ensuring that the first sling 2 and the cable 1 are under the same tension conditions, thereby reducing costs. In addition, the relative displacement between the counterweight 6 and the main beam can be greatly increased, thereby improving the vibration control efficiency.

[0014] The second sling 5 may be made of high-strength fiber material to ensure sufficient strength, rigidity and durability, and the material type, size and quantity are not limited.

[0015] The material type, size and quantity of the counterweight block 6 are not limited. The counterweight block 6 may be made of water tank, sand box, concrete, steel block and the like. The quantity and quality of the counterweight block 6 may be determined according to the needs.

[0016] The damping element 7 has no limit on type, quantity and installation position, has a long service life and good economy. When a counterweight block 6 is set, it is recommended to be installed between the counterweight block 6 and the bottom plate of the main beam. When a tension spring 11 is set, it is recommended to be installed between the cable 1 and the bottom plate of the main beam.

[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, which can prevent rainwater and dust from entering the hole protection bushing 3 and the main beam 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 beam. 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 has sufficient strength, rigidity and durability, and the material type, size and quantity are not limited. The cable 1 can be disconnected and fixed at the second pulley 9, or it can be continuously allowed to slide in the longitudinal direction.

[0019] The third pulley 10 has sufficient strength, rigidity and durability, and the material type and size are not limited.

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

[0021] Without the first pulley 4 and the second sling 5, the first sling 2 can be directly connected to the counterweight 5 to dissipate energy and suppress vibration. In this case, a larger counterweight 6 is required.

[0022] The two schemes of placing cable 1 inside and outside the main beam have their own advantages and disadvantages, and a comprehensive comparison and selection should be made considering multiple factors.

[0023] Two sets of the device are set on both sides of the main beam cross bridge. By increasing the area of ​​the cable 1, the mass of the counterweight 6, the damping force of the damping element 7, etc., the bridge can be provided with greater resistance and a higher damping ratio, and the critical wind speed of the soft flutter of the bridge, which is mainly torsional vibration, can be greatly increased, and its amplitude can be reduced. The device also plays a beneficial role in controlling the bridge buffeting and the bridge vibration caused by the traffic load.

[0024] The beneficial effects of the present invention are as follows: (1) Lower construction and maintenance costs: It can control multiple vortex vibrations, reducing the need for multiple tuning devices, thereby significantly reducing the overall construction cost; (2) Unrestricted control frequency: The device is simple in design, does not require complex tuning, and is not limited by the vortex vibration frequency, breaking through the bottleneck problem that the traditional TMD cannot be applied to low-frequency vortex vibration control due to the excessive static deformation of the spring; (3) Smaller additional load: When the cable is placed outside the main beam, compared with the traditional TMD, the first pulley not only avoids the additional vertical load added by the counterweight block, but also provides vertical support for the bridge. Each counterweight block increases the stiffness of the cable and contributes to the control of each order of modal vortex vibration. Therefore, unlike the traditional TMD control of each order of modal vortex vibration, sufficient counterweight is required; when the cable is placed inside the main beam, each counterweight block and / or tension spring increases the stiffness of the cable, providing the same vertical stiffness for the cable, and the mass of the required tension spring is much smaller than the mass of the counterweight block. (4) Can control multiple vibrations: In addition to vortex vibration control, the device can also effectively control buffeting, flutter and vibration caused by vehicle load. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

[0028] The specific implementation modes of the present invention are described in detail below in combination with the technical solutions and the accompanying drawings, but the implementation modes of the present invention are not limited thereto.

[0029] like Figure 1 and 2As shown, a vortex vibration control device for a large-span bridge is proposed, which includes a cable 1, a first suspension cable 2, a hole protection bushing 3, a first pulley 4, a second suspension cable 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 beam: first, one or more cables 1 are anchored at the appropriate positions of the bridge at both ends, so that the cable 1 is suspended horizontally along the longitudinal direction of the bridge; a plurality of first suspension cables 2 are suspended at different positions of the cable 1, and the lower ends thereof are wound around the first pulley 4 installed inside the main beam after passing through the hole protection bushing 3 of the bridge deck top plate hole, and are fixed thereto; the second suspension cable 5 is wound around the first pulley 4 in the opposite direction to the first suspension cable 2, one end of which is fixed to the first pulley, and the other end of which suspends the counterweight 6; the damping element 7 is installed between the counterweight 6 and the main beam; the waterproof cover 8 which can be retracted up and down is sleeved outside the first suspension cable 2, the lower end of which is adhered and fixed to the bridge deck, and the upper end is tightly bound to the first suspension cable 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, so that it has sufficient vertical stiffness. The bridge main beam produces a vertical relative displacement relative to the cable 1 and the counterweight 6, and the damping element 7 provides a damping force for the main beam, thereby dissipating energy to control vortex vibration. If the cable 1 is placed in the main beam: the cable 1 is suspended horizontally along the longitudinal direction of the bridge, and its two ends are anchored at appropriate positions inside the main beam. A number of second pulleys 9 are arranged longitudinally on the top plate inside the main beam to provide support for the cable 1; the upper ends of a number of first slings 2 are suspended at different cross-sectional positions of the cable 1, and the lower ends are wound on the third pulley 10 installed inside the main beam, and are guided by the third pulley 10 and then wound and fixed on the first pulley 4; 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 guides the first sling 2 at different cross-sectional positions of the cable 1, a number of horizontally arranged tension springs 11 are used to provide sufficient vertical stiffness for the cable 1, thereby eliminating the need for the first pulley 4, the second sling 5 and the counterweight 6. If the first pulley 4 and the second sling 5 are not provided, the first sling 2 is directly connected to the counterweight 6, which can also dissipate energy and suppress vibration. The cable 1 is inside the main beam. If the first suspension cable 2 is further eliminated and the counterweight 6 is directly placed on the cable 1, energy dissipation and vibration suppression can also be achieved. The specific selection method is determined according to actual conditions.

[0030] The above is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any equivalent changes, modifications or evolutions made by those skilled in the art to the above examples using the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A vortex vibration control device for a long-span bridge, characterized in that: The large-span bridge vortex vibration control device comprises a cable (1), a first suspension cable (2), a hole protection bushing (3), a first pulley (4), a second suspension cable (5), a counterweight (6), a damping element (7) and a waterproof cover (8); If the cable (1) is located outside the bridge main beam: the cable (1) is suspended horizontally along the longitudinal direction of the bridge, and its two ends are anchored on the bridge tower or arch rib; the upper ends of a plurality of first suspension cables (2) are suspended at different cross-sectional positions of the cable (1), and their lower ends are passed through the holes in the bridge deck top plate and the hole protection bushing (3), and are wound and fixed on the first pulley (4) installed inside the bridge main beam; one end of the second suspension cable (5) is wound and fixed on the first pulley (4) in the opposite direction to the first suspension cable (2), and the other end suspends a counterweight (6); the damping element (7) is installed between the counterweight (6) and the bridge main beam, for vortex vibration control of large-span bridges. The device provides damping force; a waterproof cover (8) that can be extended and retracted upward and downward is sleeved outside the first suspension cable (2), the lower end of which is adhered and fixed to the bridge deck, and the upper end of which is tightly bound to the first suspension cable (2); using the above structure, a plurality of discrete vertical loads are applied to the cable (1) through a plurality of counterweight blocks (6), a second suspension cable (5), a first pulley (4), and a first suspension cable (2) arranged along the longitudinal direction of the bridge, so that the cable (1) has sufficient vertical stiffness; if the bridge main beam generates vertical relative displacement relative to the cable (1) and the counterweight block (6), the damping element (7) provides damping force for the bridge main beam, thereby dissipating energy to control vortex vibration; If the cable (1) is placed in the main beam of the bridge: the vortex vibration control device for the large-span bridge 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 suspended horizontally along the longitudinal direction of the bridge, and its two ends are anchored inside the main beam. A plurality of second pulleys (9) are arranged in the longitudinal direction of the top plate inside the main beam of the bridge to provide support for the cable (1); the upper ends of a plurality of first slings (2) are suspended at different cross-sectional positions of the cable (1), and the lower ends are wrapped around the cable (1). The cable (1) is wound around a third pulley (10) installed inside the main beam of the bridge, and is guided by the third pulley (10) and then wound and fixed on the first pulley (4); 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 a counterweight (6) is suspended on the other end; after the third pulley (10) at different cross-sectional positions of the cable (1) guides the first sling (2), a plurality of horizontally arranged tension springs (11) are used to provide sufficient vertical stiffness for the cable (1).

2. The vortex vibration control device for a long-span bridge according to claim 1 is characterized in that: The first pulley (4) and the second sling (5) are not provided, and the first sling (2) is directly connected to the counterweight (6), which can also dissipate energy and suppress vibration; the cable (1) is inside the main beam of the bridge, and the first sling (2) is further eliminated, and the counterweight (6) is directly placed on the cable (1), which can also dissipate energy and suppress vibration.

3. The vortex vibration control device for a long-span bridge according to claim 1 is characterized in that: The cable (1) is arranged at the transverse center of the bridge main beam and is made of high-strength parallel steel wires and high-strength fiber materials.

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

5. The vortex vibration control device for a long-span bridge according to claim 1 is characterized in that: Two sets of large-span bridge vortex vibration control devices are installed on both sides of the main beam cross bridge to suppress torsional vortex vibration and flutter.

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