Protection device for inhibiting vortex vibration of cable of cable-stayed bridge

Abstract

The invention relates to the technical field of cable-stayed bridge cable vibration reduction, in particular to a protection device for restraining cable vortex vibration of a cable-stayed bridge, the protection device comprises a mounting sleeve connected to the exterior of a cable-stayed bridge cable in a sleeving mode and a plurality of outward-extending wings arranged outside the mounting sleeve, and the outward-extending wings are provided with a plurality of air holes penetrating through the side walls of the outward-extending wings at intervals in the length direction of the outward-extending wings; the air holes comprise first air holes and second air holes which are the same in shape and are alternately formed in the length direction of the extension wing, the section of an air inlet of each first air hole is larger than that of an air outlet, and the section of an air inlet of each second air hole is smaller than that of the air outlet. The local wind speed can be increased, the wind speed and the wind field condition generated by vortex vibration are fundamentally changed, then the vortex falling frequency is far away from the natural vibration frequency of the cable, and therefore the possibility of vortex vibration is reduced; the influence of fluctuating wind can be weakened, the safety and stability of the cable-stayed bridge cable are improved, and fatigue damage is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of cable-stayed bridge cable vibration reduction, and in particular to a protective device for suppressing cable vortex vibration of a cable-stayed bridge. Background Art

[0002] With the steady progress of my country's infrastructure construction, the number of cross-sea bridges and bridges across canyons has gradually increased. Cable-supported bridges are widely used due to their strong spanning capacity. Whether it is a bridge across the sea or across a canyon, it has to face severe and harsh wind environments. For cable-supported bridges, the wind resistance of each component is a key factor in the design. Among them, the cable-stayed bridge cable is more susceptible to air flow due to its long and thin shape, which triggers eddy vibration. As the wind speed increases, the amplitude and frequency of the eddy vibration usually increase significantly. The change of wind direction also has a significant impact on the eddy vibration characteristics. The vibration reduction measures for the cable-stayed bridge cables in the prior art are mainly to set a support at the bottom end of the cable-stayed bridge cable to provide vibration reduction support for the cable-stayed bridge cable, but this is bound to increase the space occupied by the vibration reduction device. As for the prior art of directly setting a vibration reduction device on the cable-stayed bridge cable, a driving device is generally set to achieve active vibration reduction, but external energy input is required. The additional active control equipment makes the structure more complicated, and the construction and maintenance costs are high. As for the vibration reduction device that does not require external energy input, components with different cross-sectional areas are directly mounted on the cable-stayed bridge cable to change the original cross-sectional area of ​​the cable-stayed bridge cable. Although the generation of eddy vibration can be suppressed to a certain extent, its wind resistance performance is still not improved, and the wind load received by the cable-stayed bridge cable cannot be reduced. Therefore, designing a protective device for suppressing vortex vibration of cable-stayed bridges can not only automatically suppress eddy current vibration, but also reduce the wind load on the cables of cable-stayed bridges, which is a technical problem that technical personnel in this field urgently need to solve. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a protective device for suppressing vortex vibration of the cable of a cable-stayed bridge. By arranging outward wings on the surface of the cable-stayed bridge and arranging through wind holes with alternately changing cross-sectional areas on the front and back sides of the outward wings, the direction of the airflow can be changed. When the airflow flows through the second wind hole with a small air inlet and a large air outlet, the wind speed can be weakened, the wind load on the cable of the cable-stayed bridge can be reduced, the safety and stability of the cable-stayed bridge cable structure can be improved, and fatigue damage can be reduced. When the airflow flows through the first wind hole with a large air inlet and a small air outlet, the local wind speed can be increased. After the local wind speed increases, the frequency of vortex shedding will also increase, thereby making the vortex shedding frequency away from the natural frequency of the structure, thereby reducing vortex vibration, and can fundamentally change the wind speed and wind field conditions that cause vortex vibration.

[0004] In order to achieve the purpose of the present invention, the technical solution adopted by the present invention is: The present invention discloses a protective device for suppressing vortex vibration of a cable-stayed bridge, comprising a mounting sleeve sleeved on the outside of the cable of the cable-stayed bridge and a plurality of outward-spreading wings arranged on the outside of the mounting sleeve, wherein the outward-spreading wings are provided with a plurality of wind holes penetrating the side walls of the outward-spreading wings at intervals along the length direction thereof, the wind holes comprising a first wind hole and a second wind hole of the same shape and alternately arranged in the length direction of the outward-spreading wings, the cross-sectional width of the air inlet of the first wind hole being greater than the cross-sectional width of the air outlet, the cross-sectional width of the air inlet of the second wind hole being less than the cross-sectional width of the air outlet, and the air inlet and the air outlet of the first wind hole and the second wind hole are both located on the same side of the outward-spreading wing.

[0005] The mounting sleeve comprises a first fixing ring and a second fixing ring which are sleeved on both ends of the outer side of the cable-stayed bridge cable, the outer walls of the first fixing ring and the second fixing ring are respectively connected to the inner wall of the bearing, and the inner end of the outwardly spread wing is fixed on the outer wall of the bearing.

[0006] The outer wall of the bearing is in a circular array with no less than three outward wings, and the outward wings are in an "S"-shaped structure. An air guide groove is formed between the inner walls of adjacent outward wings, and the air guide groove is an "S"-shaped structure along the axial direction of the cable-stayed bridge cable.

[0007] The outer wall of the bearing is provided with a plurality of dovetail grooves in an annular array, and the inner end of the outwardly spread wing is provided with a dovetail matched and plugged with the dovetail groove.

[0008] The cross-sectional shape of the air hole is trumpet-shaped or funnel-shaped.

[0009] The air holes are arranged on the outward-spreading wings in a spiral line.

[0010] The outward-spreading wings are made of glass fiber reinforced plastic.

[0011] The beneficial effects of the present invention are: (1) The present invention can change the direction of airflow by arranging outward wings on the surface of the cable-stayed bridge cable and arranging through air holes with alternating cross-sectional areas on the front and back sides of the outward wings. When the airflow flows through the second air hole with a small air inlet and a large air outlet, the wind speed can be weakened, the wind load on the cable-stayed bridge cable can be reduced, the safety and stability of the cable-stayed bridge cable structure can be improved, and fatigue damage can be reduced. When the airflow flows through the first air hole with a large air inlet and a small air outlet, the local wind speed can be increased. After the local wind speed increases, the frequency of vortex shedding will also increase, thereby making the vortex shedding frequency away from the natural frequency of the structure, thereby reducing vortex vibration, and fundamentally changing the wind speed and wind field conditions caused by vortex vibration.

[0012] (2) The outward-spreading wings of the present invention are oriented in an S-shape. Two adjacent outward-spreading wings will form a wind guide groove along the axial direction of the inclined cable, which will rotate with the wind force, further facilitating the destruction of the wind direction angle and wind attack angle required for generating vortex vibration. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a front view of a protective device for suppressing vortex vibration of a cable-stayed bridge according to the present invention; Figure 2 Figure 1 The cross section along AA in the figure; Figure 3 The present invention is a schematic structural diagram of a protective device for suppressing vortex vibration of cables of a cable-stayed bridge.

[0014] In the figure: 1 first fixing ring, 2 outward wings, 3 wind holes, 31 first wind holes, 32 second wind holes, 4 bearings, 5 cable-stayed bridge cables, 6 second fixing rings, 7 wind guide slots. DETAILED DESCRIPTION

[0015] The present invention is further described below: See also Figure 1-3 , The present invention discloses a protective device for suppressing vortex vibration of cable-stayed bridge. Figure 1-3 As shown, it includes a mounting sleeve sleeved on the outside of the cable-stayed bridge cable 5 and a plurality of outward wings 2 arranged outside the mounting sleeve, the outward wings 2 are provided with a plurality of air holes 3 passing through the side walls of the outward wings 2 at intervals along the length direction thereof, the air holes 3 include first air holes 31 and second air holes 32 of the same shape and alternately arranged in the length direction of the outward wings 2, the air inlet cross-sectional width of the first air holes 31 is greater than the air outlet cross-sectional width, the air inlet cross-sectional width of the second air holes 32 is less than the air outlet cross-sectional width, the air inlets and air outlets of the first air holes 31 and the second air holes 32 are both located on the same side of the outward wings 2, and the outward wings 2 are provided with air holes 31 and 32 on the surface of the cable-stayed bridge cable 5. The wings are spread 2, and through wind holes 3 with alternately changing cross-sectional areas are arranged on the front and back sides of the outwardly spread wings 2, which can change the flow direction of the airflow. When the airflow flows through the second wind hole 32 with a small air inlet and a large air outlet, the wind speed can be weakened, the wind load on the cable-stayed bridge cable 5 can be reduced, the safety and stability of the cable-stayed bridge cable 5 structure can be improved, and fatigue damage can be reduced. When the airflow flows through the first wind hole 31 with a large air inlet and a small air outlet, the local wind speed can be increased. After the local wind speed increases, the frequency of vortex shedding will also increase, thereby making the vortex shedding frequency away from the natural frequency of the structure, thereby reducing vortex vibration, which can fundamentally change the wind speed and wind field conditions caused by vortex vibration.

[0016] Further, such as Figure 1As shown, the mounting sleeve includes a first fixing ring 1 and a second fixing ring 6 which are sleeved on both ends of the outside of the cable-stayed bridge cable 5, the outer walls of the first fixing ring 1 and the second fixing ring 2 are respectively connected to the inner wall of the bearing 4, and the inner end of the outward-spreading wing 2 is fixed on the outer wall of the bearing 4. By fixing the outward-spreading wing 2 on the outer wall of the bearing 4, the outward-spreading wing 2 can automatically adapt to the wind direction, and the outward-spreading wing 2 is driven to rotate on the cable-stayed bridge cable 5 by the airflow, which can effectively interfere with the airflow on the surface of the cable-stayed bridge cable 5, reduce the formation and shedding of vortices, and thus reduce vortex vibration.

[0017] Furthermore, the installation sleeve can be directly sleeved onto the outer surface of the installed cable-stayed bridge cable 5 in a snap-fitting manner, that is, the installation sleeve is surrounded by a snap-fitting structure into a sleeve form to complete the clamping of the cable-stayed bridge cable 5. The snap-fitting structure can be a combination of a buckle, a hook and a mounting hole, as well as any structure that can achieve the snap-fitting of the installation sleeve. The installation sleeve can also be directly set to a cylindrical structure, that is, the sleeve of the cable-stayed bridge cable 5 is completed before the cable-stayed bridge cable 5 is installed; the outer wall of the bearing 4 and the outward wing 2 are connected by plug-in cooperation, and the outward wing 2 can be removed through the plug-in structure when the outward wing 2 needs maintenance or replacement, thereby reducing maintenance costs and work difficulty; for example, a dovetail groove is provided on the outer surface of the bearing 4, and a dovetail that matches and plugs into the dovetail groove is provided on the inner wall of the outward wing 2. When the outward wing 2 needs to be installed on the bearing 4, the dovetail groove and the dovetail structure are directly plug-fitted to achieve the fixation of the outward wing 2, which can reduce the difficulty of disassembling the outward wing 2.

[0018] Further, such as Figure 2 and Figure 3 As shown, the outer wall of the bearing 4 is in a circular array with no less than three outward wings 2, and the outward wings 2 are in an "S"-shaped structure. Wind guide grooves 7 are formed between the inner walls of adjacent outward wings 2. The wind guide grooves 7 are in an "S"-shaped structure along the axial direction of the cable-stayed bridge cable 5. Two adjacent outward wings 2 will form a wind guide groove 7 along the axial direction of the cable-stayed cable, which will rotate with the wind force, and the outward wings 2 will be driven to rotate by the airflow, so that the outward wings 2 can automatically adjust the angle according to the direction and intensity of the wind, optimize the aerodynamic effect, and achieve continuous suppression of vortex vibration; the direction of the outward wings 2 is S-shaped, and two adjacent outward wings will form a wind guide groove along the axial direction of the cable-stayed cable, which will rotate with the wind force, which is further conducive to destroying the wind direction angle and wind attack angle required for generating vortex vibration.

[0019] Further, such as Figure 2 As shown, the cross-sectional shape of the wind hole 3 is trumpet-shaped or funnel-shaped. The design of the funnel-shaped hole and the trumpet-shaped hole can guide the airflow to flow more smoothly through the surface of the cable-stayed bridge cable 5, reduce airflow separation and vortex formation, and thus reduce wind-induced vibration.

[0020] Further, such as Figure 1 and 3As shown, the air holes 3 are arranged on the outwardly spread wings 2 in a spiral shape. The spirally distributed air holes 3 are helpful to disrupt the laminar structure of the airflow, promote the mixing of the airflow, and thus reduce the formation of vortices.

[0021] Further, such as Figure 1 and 3 As shown, the air holes 3 are arranged in a plum blossom shape, and the air holes 3 with a small cross-sectional area can be arranged at the center of the plum blossom structure, or can be arranged circumferentially of the plum blossom structure, or can be staggered with the air holes 3 with a large cross-sectional area.

[0022] Furthermore, the outward-spreading wing 2 is made of glass fiber reinforced plastic. Since the outward-spreading wing 2 made of glass fiber reinforced plastic is lighter in weight, the burden of the outward-spreading wing 2 on the cable 5 of the cable-stayed bridge can be reduced. It should be noted that, except for the bearing 4 structure, other structures of the protective device for suppressing vortex vibration of the cable-stayed bridge can be set to glass fiber reinforced plastic, and except for glass fiber reinforced plastic, other materials that can reduce the weight of the protective device can be used to make the protective device components except for the bearing 4.

[0023] The method of using the present invention is as follows: insert the inner end of the outward-spreading wing 2 into the outer wall of the bearing 4, then sleeve the two bearings 4 on the outer walls of the first fixing ring 1 and the second fixing ring 6, and then snap the first fixing ring 1 and the second fixing ring 6 onto the outer wall of the cable-stayed bridge cable 5. Because the through-wind holes 3 with alternating cross-sectional areas are arranged on the front and back sides of the outward-spreading wing 2, the flow direction of the airflow can be changed. When the airflow flows through the wind hole 3 with a small inlet and a large outlet, the wind speed can be weakened, the wind load on the cable-stayed bridge cable 5 can be reduced, the safety and stability of the cable-stayed bridge cable 5 structure can be improved, and fatigue damage can be reduced. When the airflow flows through the wind hole 3 with a large inlet and a small outlet, the local wind speed can be increased. After the local wind speed increases, the frequency of vortex shedding will also increase, thereby making the vortex shedding frequency far away from the natural frequency of the structure, thereby reducing vortex vibration, and fundamentally changing the wind speed and wind field conditions generated by vortex vibration. Moreover, through the rotation of the outward-spreading wing 2, the airflow on the surface of the cable-stayed bridge cable 5 can be effectively interfered with, the formation and shedding of vortices can be reduced, thereby reducing vortex vibration.

[0024] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent transformations made using the contents of the present invention's specification and drawings or directly or indirectly applied in related technical fields are also included in the patent protection scope of the present invention.

Claims

1. A protective device for suppressing vortex vibration of cable-stayed bridge, characterized in that: The invention comprises a mounting sleeve sleeved on the outside of a cable-stayed bridge cable (5) and a plurality of outward-spreading wings (2) arranged outside the mounting sleeve, wherein the outward-spreading wings (2) are provided with a plurality of air holes (3) penetrating the side walls of the outward-spreading wings (2) at intervals along the length direction thereof, wherein the air holes (3) comprise first air holes (31) and second air holes (32) of the same shape and arranged alternately in the length direction of the outward-spreading wings (2), wherein the width of the air inlet cross section of the first air hole (31) is greater than the width of the air outlet cross section, and the width of the air inlet cross section of the second air hole (32) is less than the width of the air outlet cross section, and the air inlets and air outlets of the first air hole (31) and the second air hole (32) are both located on the same side of the outward-spreading wings (2).

2. A protective device for suppressing vortex vibration of a cable-stayed bridge according to claim 1, characterized in that: The mounting sleeve comprises a first fixing ring (1) and a second fixing ring (6) which are sleeved on the two ends of the outside of the cable-stayed bridge cable (5); the outer walls of the first fixing ring (1) and the second fixing ring (2) are respectively connected to the inner wall of the bearing (4); and the inner end of the outward-spreading wing (2) is fixed to the outer wall of the bearing (4).

3. A protective device for suppressing vortex vibration of cable-stayed bridge according to claim 2, characterized in that: The outer wall of the bearing (4) is in the form of a circular array with no less than three outward-spreading wings (2), the outward-spreading wings (2) are in an "S"-shaped structure, and an air guide groove (7) is formed between the inner walls of adjacent outward-spreading wings (2), the air guide groove (7) is in an "S"-shaped structure along the axial direction of the cable-stayed bridge cable (5).

4. A protective device for suppressing vortex vibration of a cable-stayed bridge according to claim 3, characterized in that: The outer wall of the bearing (4) is provided with a plurality of dovetail grooves in an annular array, and the inner end of the outwardly spread wing (2) is provided with a dovetail that matches and plugs into the dovetail groove.

5. The protective device for suppressing vortex vibration of cable-stayed bridge according to claim 1, characterized in that: The cross-sectional shape of the air hole (3) is trumpet-shaped or funnel-shaped.

6. The protective device for suppressing vortex vibration of cable-stayed bridge according to claim 1, characterized in that: The air holes are arranged in a spiral line on the outward-spreading wing (2).

7. The protective device for suppressing vortex vibration of cable-stayed bridge according to claim 1, characterized in that: The outwardly extending wings (2) are made of glass fiber reinforced plastic.

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