Inhaul cable multi-point energy dissipation and vibration reduction system

Abstract

The invention relates to the technical field of structural vibration reduction, in particular to an inhaul cable multipoint energy dissipation and vibration reduction system which comprises an inhaul cable, a main damper, an auxiliary damper and a high-order damper, the main damper, the auxiliary damper and the high-order damper are arranged on the inhaul cable, one end of the inhaul cable is connected with a bridge girder, the other end of the inhaul cable is connected with a tower, and guide pipes are arranged at the two ends of the inhaul cable; the main shock absorber is installed on the side, close to a bridge girder or a tower, of the inhaul cable through a support, and the auxiliary shock absorber is installed on the side, away from the main shock absorber, of the inhaul cable. The high-order shock absorber is arranged on one side close to the main shock absorber or the auxiliary shock absorber, and the three shock absorbers are installed at different positions respectively. The main shock absorber is used for resisting low-order vibration of the cable; the auxiliary shock absorber is used for adjusting the multi-mode damping effect; the high-order damper is used for resisting high-frequency vortex-induced vibration. The inhaul cable multi-point energy dissipation and vibration reduction system has the advantages that the vibration reduction control frequency band is widened, the installation distance of the damper is reduced, and the maintainability of the vibration reduction system is improved.

Description

Technical Field

[0001] The invention relates to the technical field of structural vibration reduction, in particular to a cable multi-point energy dissipation vibration reduction system. Background Art

[0002] Cable structures are widely used in civil engineering infrastructure and are key core load-bearing components, such as the cables of suspension bridges and arch bridges, the cables of cable-stayed bridges and cable-stayed-cable assisted bridges, and cable structures are also very common in large-span venues and tall meteorological towers. Cables are long and small in cross-sectional area, with large axial stiffness and very small lateral stiffness and very low self-damping. Therefore, they are prone to vibration under the action of wind, rain, wind and sand, etc. The vibration has the characteristics of low wind speed initiation, long duration, and multi-modal vibration in a wide frequency band. Cable vibration control still faces challenges, and the challenges become greater as the bridge span and cable length increase.

[0003] At present, the conventional solution for cable vibration control is to combine pneumatic measures with mechanical vibration reduction devices. The pneumatic measures mainly include winding spiral wires and pressing pits on the surface of the cable sheath, which destroy the coupling mechanism between the cable and wind and rain to reduce vibration. In terms of mechanical device vibration reduction, the main method is to add a damper near the anchor point of the cable, connect the cable to its supporting structure laterally within the span, and make the vibration reduction device consume energy to reduce vibration when the cable vibrates laterally. However, there are still several problems with cable mechanical device vibration reduction: (1) The single-point installation of the mechanical device cannot cover the multi-modal vibration of the cable, especially the long cable. The cable installed with the vibration reduction device still has high-order vibration observed on the actual bridge; (2) As the cable length increases, the installation position of the mechanical device needs to be farther and farther away from the anchor point to obtain sufficient damping effect, which brings three problems: uneconomical, unsightly and difficult to maintain.

[0004] In response to the first problem mentioned above, some recent studies and patents have solved it by adding a vibration reduction device, including adding a damper near or at the other end of the original vibration damper (CN111963618A-a method for controlling multi-order modal vibration of cables based on dual dampers) or adding a vibration damping hammer (CN111796611A-a method for controlling multi-modal vibration of cables) and (CN112227180A-a combined vibration reduction device and method for inclined cables). However, the above patents still cannot solve the second problem. Moreover, measures such as adding a damper at the same end of the original damper may also reduce the vibration reduction effect of the original damper on the low-order modal vibration of the cable, and further need to increase the installation distance (or height) of the original damper.

[0005] Therefore, it is very important to provide a vibration reduction system that can solve the above technical problems. Summary of the invention

[0006] In order to solve the above problems, the purpose of the present invention is to provide a cable multi-point energy dissipation vibration reduction system, which can achieve wide-band multi-modal vibration reduction while ensuring that each shock absorber is installed close to the anchor point, so that the system has both control effect and engineering applicability.

[0007] The purpose of the present invention can be achieved by the following technical solutions:

[0008] The present invention provides a cable multi-point energy dissipation vibration reduction system, comprising a cable installed between a bridge main beam and a tower, and a main vibration absorber, an auxiliary vibration absorber and a high-order vibration absorber arranged on the cable.

[0009] One end of the cable is connected to the bridge main beam through a conduit, and the other end is connected to the tower through a conduit; the main shock absorber is installed on the side of the cable close to the bridge main beam or tower through a bracket, and the auxiliary shock absorber is installed on the side of the cable away from the main shock absorber;

[0010] Among them, three types of shock absorbers are installed at different positions on the cable;

[0011] The main vibration absorber is used to resist the low-order vibration of the cable, targeting the vibration of the cable in the frequency range of 0 to 3 Hz;

[0012] The auxiliary shock absorber is used to adjust the multi-modal damping effect and reduce the distance between the main shock absorber and the adjacent anchor point;

[0013] The high-order vibration absorber is used to resist high-frequency vortex-induced vibration. For the modes of the main vibration absorber and the auxiliary vibration absorber located at the cable vibration type stagnation point, the modal damping of the cable in the frequency range of 0 to 15 Hz is improved to meet the vortex vibration control requirements (especially for the high-order modes of the main vibration absorber and the auxiliary vibration absorber close to the cable vibration type stagnation point).

[0014] In one embodiment of the present invention, the central axes of the main shock absorber and the bracket are perpendicular to the cable.

[0015] In one embodiment of the present invention, one end of the main shock absorber is movably connected to the cable through a cable clamp and a ball joint, and the other end is also movably connected to the bracket through a ball joint.

[0016] In one embodiment of the present invention, one end of the bracket is fixedly connected to the main beam or tower of the bridge, and the other end is movably connected to the main shock absorber.

[0017] In one embodiment of the present invention, the distance between the main shock absorber and the anchor point (upper anchor point (upper end of the cable) or lower anchor point (lower end of the cable)) is 2% to 5% of the cable length.

[0018] In one embodiment of the present invention, the distance between the auxiliary shock absorber and the anchor point (upper anchor point (upper end of the cable) or lower anchor point (lower end of the cable)) is 0 to 2% of the cable length;

[0019] Preferably, the auxiliary shock absorber is installed at the lower port of the conduit at the upper end of the cable.

[0020] In one embodiment of the present invention, more than one high-order vibration absorber is provided.

[0021] In one embodiment of the present invention, the high-order shock absorber is arranged on a side close to the main shock absorber or the auxiliary shock absorber.

[0022] In one embodiment of the present invention, when the cable is in a stationary state, the center axis of the bracket is identical to the center axis of the main shock absorber.

[0023] In one embodiment of the present invention, the auxiliary shock absorber and the high-order shock absorber are connected to the cable through a conduit;

[0024] The auxiliary vibration absorber and the high-order vibration absorber are both independently arranged at the end of the conduit, and the end of the conduit connected to the auxiliary vibration absorber or the high-order vibration absorber is provided with a waterproof protective cover.

[0025] In one embodiment of the present invention, the main shock absorber (using a damper with small self-stiffness and good energy dissipation performance) is selected from one of a viscous damper, a viscous shear damper, a magnetorheological damper or an eddy current damper.

[0026] In one embodiment of the present invention, the auxiliary shock absorber (the damper is selected according to the cable end attachment conditions) is selected from one of a viscous damper, a viscous shear damper or a high damping rubber damper.

[0027] In one embodiment of the present invention, the high-order vibration absorber (a damper with good broadband and small amplitude vibration reduction performance) is selected from one of a high damping rubber damper, a tuned mass damper, a vibration damping hammer or a wire rope damper.

[0028] In the present invention, the main shock absorber is preferably installed at the lower end of the cable to facilitate installation, adjustment, detection and maintenance.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] (1) The cable multi-point energy dissipation vibration reduction system provided by the present invention utilizes auxiliary vibration absorbers to improve the effect of the main vibration absorber in suppressing the low-order vibration of the cable, thereby reducing the required installation distance of the main vibration absorber, improving the installability and maintainability of the main vibration absorber, and reducing the cost of the main vibration absorber support structure;

[0031] (2) The auxiliary shock absorber and the high-order shock absorber in the cable multi-point energy dissipation and vibration reduction system provided by the present invention can be installed using the cable guide tube as a support, thereby solving the multi-modal vibration reduction problem while ensuring economy and aesthetics.

[0032] (3) The present invention combines the main shock absorber, the auxiliary shock absorber and the high-order shock absorber to achieve the widening of the frequency band covered by the vibration reduction control, and at the same time plays a protective role near the anchor point of the cable, improves the waterproof and moisture-proof performance of the cable anchor end and prolongs the fatigue life of the cable. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A schematic diagram of the structure of the cable multi-point energy dissipation and vibration reduction system provided in Example 1;

[0034] Figure 2 A schematic diagram of the structure of the main shock absorber and the bracket in the cable multi-point energy dissipation and vibration reduction system provided in Example 1;

[0035] Figure 3 A schematic diagram of the structure of the cable, auxiliary shock absorber and conduit in the cable multi-point energy dissipation and shock absorption system provided in Example 1;

[0036] Figure 4 A schematic diagram of the structure of the cable, the high-order vibration absorber and the conduit in the cable multi-point energy dissipation vibration reduction system provided in Example 1;

[0037] Figure 5 This is a schematic diagram of selecting a target cable in Example 2;

[0038] Figure 6 It is a structural schematic diagram of the cable multi-point energy dissipation and vibration reduction system in Example 2;

[0039] Figure 7 Schematic diagram of multi-modal damping effect when dual dampers are used in Example 2;

[0040] Figure 8 The effect of using viscous dampers for both the main shock absorber and the auxiliary shock absorber and using high-damping rubber dampers for the high-order shock absorber in Example 2;

[0041] Numbers in the figure: 1. Cable; 2. Conduit; 3. Main shock absorber; 4. Auxiliary shock absorber; 5. High-order shock absorber; 6. Bracket; 7. Waterproof protective cover; 8. Bridge main beam; 9. Tower; 10. Tower outer wall; 11. Tower center. DETAILED DESCRIPTION

[0042] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0043] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0044] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0045] In the description of this embodiment, terms such as "up", "down", "left", and "right" and other orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0046] In the following embodiments, unless otherwise specified, the structures or components used are conventional structures and components in the art, as long as they can achieve the corresponding functions.

[0047] Example 1

[0048] This embodiment provides a cable multi-point energy dissipation and vibration reduction system, such as Figures 1 to 4 As shown, it includes a cable 1 installed between a bridge main beam 8 and a tower 9, and a main shock absorber 3, an auxiliary shock absorber 4 and a high-order shock absorber 5 arranged on the cable 1.

[0049] One end of the cable 1 is connected to the bridge main beam 8 through a conduit 2, and the other end is connected to the tower 9 through a conduit 2; the main shock absorber 3 is installed on the side of the cable 1 close to the bridge main beam 8 or the tower 9 through a bracket 6, and the auxiliary shock absorber 4 is installed on the side of the cable 1 away from the main shock absorber 3;

[0050] Among them, three types of shock absorbers are installed at different positions on the cable 1;

[0051] The main shock absorber 3 is used to resist the low-order vibration of the cable, targeting the vibration of the cable in the frequency range of 10 to 3 Hz;

[0052] The auxiliary shock absorber 4 is used to adjust the multi-modal damping effect and reduce the distance between the main shock absorber 3 and the adjacent anchor point;

[0053] The high-order vibration absorber 5 is used to resist high-frequency vortex-induced vibration. For the modes of the main vibration absorber 3 and the auxiliary vibration absorber 4 located at the stagnation point of the cable vibration type, the modal damping of the cable in the frequency range of 0 to 15 Hz is improved to meet the vortex vibration control requirements (especially for the high-order modes of the main vibration absorber 3 and the auxiliary vibration absorber 4 close to the stagnation point of the cable vibration type 1).

[0054] Furthermore, the central axes of the main shock absorber 3 and the bracket 6 are perpendicular to the cable 1; one end of the main shock absorber 3 is movably connected to the cable 1 through a cable clamp and a ball joint, and the other end is also movably connected to the bracket 6 through a ball joint;

[0055] One end of the bracket 6 is fixedly connected to the bridge main beam 8 or the tower 9, and the other end is movably connected to the end of the main shock absorber 3 away from the cable 1 ( Figure 2 ).

[0056] Furthermore, the distance between the main shock absorber 3 and the anchor point (upper anchor point (upper end of the cable 1) or lower anchor point (lower end of the cable 1)) is 2% to 5% of the cable length, and the main shock absorber 3 is preferably installed at the lower end of the cable 1 to facilitate installation, adjustment, detection and maintenance;

[0057] The distance between the auxiliary shock absorber 4 and the anchor point (upper anchor point (upper end of the cable 1) or lower anchor point (lower end of the cable 1)) is 0-2% of the cable length; preferably, the auxiliary shock absorber 4 is installed at the lower port of the conduit 2 at the upper end of the cable 1.

[0058] Furthermore, more than one high-order shock absorber 5 is provided, and the high-order shock absorber 5 is provided on a side close to the main shock absorber 3 or the auxiliary shock absorber 4 .

[0059] Furthermore, when the cable 1 is in a stationary state, the central axis of the bracket 6 is the same as the central axis of the main shock absorber 3 .

[0060] Furthermore, the auxiliary shock absorber 4 and the high-order shock absorber 5 are connected to the cable 1 through the conduit 2; the auxiliary shock absorber 4 and the high-order shock absorber 5 are independently arranged at the end of the conduit 2 ( Figure 3 and Figure 4In the embodiment, the conduit 2 is connected to the auxiliary shock absorber 4 and the high-order shock absorber 5 by bolts; other connection methods can be selected according to actual conditions), and the end of the conduit 2 connected to the auxiliary shock absorber 4 or the high-order shock absorber 5 is provided with a waterproof protective cover 7 (one end of the waterproof protective cover 7 is fixed to the auxiliary shock absorber 4 or the high-order shock absorber 5, and the other end is fixed to the cable 1) ( Figure 3 and Figure 4 ).

[0061] Furthermore, the main shock absorber 3 (using a damper with small self-stiffness and good energy dissipation performance) is selected from one of a viscous damper, a viscous shear damper, a magnetorheological damper or an eddy current damper;

[0062] The auxiliary shock absorber 4 (the damper is selected according to the cable end attachment conditions) is selected from one of a viscous damper, a viscous shear damper or a high damping rubber damper;

[0063] The high-order vibration absorber 5 (a damper with good broadband and small amplitude vibration reduction performance) is selected from one of a high damping rubber damper, a tuned mass damper, a vibration damping hammer or a wire rope damper.

[0064] This embodiment can effectively suppress the low-, medium- and high-order modal vibrations of the ultra-long cable-stayed cable 1 by cooperating with the main shock absorber 3, the auxiliary shock absorber 4 and the high-order shock absorber 5, thereby solving the problems of difficulty in simultaneously controlling the low-, medium- and high-order modal vibrations of the long-span bridge and the excessively large installation distance of the shock absorbers.

[0065] Example 2

[0066] This embodiment provides a cable multi-point energy dissipation and vibration reduction system. Based on the embodiment 1, this embodiment is as follows: Figure 5 The longest cable S39 of the cable-stayed bridge shown in FIG. 1 is the target cable. The parameters of cable 1 are shown in Table 1. The vertical parameter of cable 1 is calculated to be λ 2 =1.41.

[0067] The locations for designing and installing the main shock absorber 3, the auxiliary shock absorber 4 and the high-order shock absorber 5 are as follows (eg Figure 6 shown):

[0068] One end of the cable 1 is connected to the bridge main beam 8 through a conduit 2, and the other end extends out of the tower outer wall 10 and is connected to the tower center 11 through the conduit 2; the main shock absorber 3 is installed on the side of the cable 1 close to the bridge main beam 8 through a bracket 6, and the auxiliary shock absorber 4 is installed at the position where the cable 1 is connected to the tower outer wall 10 (one end is connected to the inner wall of the tower outer wall 10, and the other end is connected to the cable 1, and the central axis of the auxiliary shock absorber 4 is perpendicular to the central axis of the cable 1); the central axes of the main shock absorber 3 and the bracket 6 are both perpendicular to the cable 1; one end of the main shock absorber 3 is movably connected to the cable 1 through a cable clamp and a ball joint, and the other end is also movably connected to the bracket 6 through a ball joint; one end of the bracket 6 is fixedly connected to the bridge main beam 8, and the other end is movably connected to the end of the main shock absorber 3 away from the cable 1; a conduit 2 is provided at the position where the cable 1 is connected to the tower outer wall 10;

[0069] Among them, the main shock absorber 3 is a viscous damper, and the installation position is 2.0% of the cable length from the lower anchor point; the auxiliary shock absorber 4 is a viscous damper, and the installation position is 9.996 / 633.24=1.5% of the cable length from the upper anchor point; the high-order shock absorber 5 is a high-damping rubber damper, the loss factor is 0.25, and the installation position is 4.524 / 633.24=0.7% of the cable length from the upper anchor point.

[0070] Table 1 Target cable parameters

[0071] Specification Cable length(m) Cable diameter(mm) Cable force(kN) Mass per unit length (kg) Fundamental frequency (Hz) Inclination angle (°) PESC7-499 633.24 201 13115.7 159 0.239 23

[0072] The first-order frequency of the cable 1 is 0.239 Hz, and the other-order frequencies are 0.227 nHz; n is the modal order. In order to control the wind-rain vibration of the cable 1, the modes below 3 Hz include the first 13 orders, and the vibration logarithmic decay rate needs to be no less than 0.03; for higher-order modes, in order to suppress vortex vibration, the vibration logarithmic decay rate needs to be no less than 0.015, and it should cover at least the first 61 orders.

[0073] Figure 7 It shows that when the existing vibration reduction system is used (viscous dampers are installed only at two points of cable 1), the beam end damper needs to be installed at 2.5% of the cable length. At this time, the logarithmic attenuation rate of the first 13 modal vibrations just meets the requirement of 0.03, and the lowest logarithmic attenuation rate in the high-order mode is 0.02, which meets the requirement; if the installation height of the beam end damper is reduced, the low-order or high-order damping cannot meet the requirements.

[0074] If the cable multi-point energy dissipation and vibration reduction system of this embodiment is adopted, Figure 8 It shows that the installation position of the main shock absorber 3 can be reduced to 2% of the cable length, while the logarithmic decay rates of low-order and high-order vibrations are improved, that is, the logarithmic decay rate of low-order vibration exceeds 0.03, and the highest logarithmic decay rate exceeds 0.026, providing more anti-vibration redundancy.

[0075] A comparison between the two-point mounted damper and the multi-point mounted damper proposed in this embodiment is shown in Table 2, which shows the important role of the system provided in this embodiment in improving the anti-vibration redundancy of the damper and reducing the installation distance of the main damper.

[0076] Table 2 Installation effect of the cable multi-point energy dissipation vibration reduction system of this embodiment and the existing vibration reduction system

[0077] Existing vibration reduction system Multi-point vibration reduction system of this embodiment Beneficial Effects Main damper installation distance 2.5% rope length 2.0% rope length 20% reduction Minimum value of 1-13th order vibration logarithmic attenuation rate 0.033 0.033 Flat Minimum value of 14-61 order vibration logarithmic attenuation rate 0.021 0.026 24% improvement

[0078] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the explanation of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A cable multi-point energy dissipation and vibration reduction system, characterized in that: The invention comprises a cable (1) installed between a bridge main beam (8) and a tower (9), and a main vibration absorber (3), an auxiliary vibration absorber (4) and a high-order vibration absorber (5) arranged on the cable (1). One end of the cable (1) is connected to the bridge main beam (8) through a conduit (2), and the other end is connected to the tower (9) through the conduit (2); the main shock absorber (3) is installed on the side of the cable (1) close to the bridge main beam (8) or the tower (9) through a bracket (6), and the auxiliary shock absorber (4) is installed on the side of the cable (1) away from the main shock absorber (3); The three types of shock absorbers are installed at different positions on the cable (1); The main vibration absorber (3) is used to resist low-order vibration of the cable; The auxiliary shock absorber (4) is used to adjust the multi-modal damping effect; The high-order vibration absorber (5) is used to resist high-frequency vortex-induced vibration.

2. A cable multi-point energy dissipation and vibration reduction system according to claim 1, characterized in that: The distance between the main shock absorber (3) and the adjacent end of the cable (1) is 2% to 5% of the cable length.

3. The cable multi-point energy dissipation and vibration reduction system according to claim 1, characterized in that: The distance between the auxiliary shock absorber (4) and the adjacent end of the cable (1) is 0 to 2% of the cable length.

4. The cable multi-point energy dissipation and vibration reduction system according to claim 1, characterized in that: More than one high-order vibration absorber (5) is provided.

5. The cable multi-point energy dissipation and vibration reduction system according to claim 1, characterized in that: The high-order shock absorber (5) is arranged on a side close to the main shock absorber (3) or the auxiliary shock absorber (4).

6. The cable multi-point energy dissipation and vibration reduction system according to claim 1, characterized in that: The auxiliary vibration damper (4) and the high-order vibration damper (5) are both independently arranged at the end of the conduit (2), and the end of the conduit (2) connected to the auxiliary vibration damper (4) or the high-order vibration damper (5) is provided with a waterproof protective cover (7).

7. The cable multi-point energy dissipation and vibration reduction system according to claim 1, characterized in that: One end of the bracket (6) is fixedly connected to the bridge main beam (8) or the tower (9), and the other end is movably connected to the main shock absorber (3).

8. The cable multi-point energy dissipation and vibration reduction system according to claim 1, characterized in that: The main shock absorber (3) is selected from one of a viscous damper, a viscous shear damper, a magnetorheological damper or an eddy current damper.

9. The cable multi-point energy dissipation and vibration reduction system according to claim 1, characterized in that: The auxiliary shock absorber (4) is selected from one of a viscous damper, a viscous shear damper or a high damping rubber damper.

10. The cable multi-point energy dissipation and vibration reduction system according to claim 1, characterized in that: The high-order vibration damper (5) is selected from one of a high-damping rubber damper, a tuned mass damper, a vibration damping hammer or a wire rope damper.

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