Swing type pneumatic device for controlling vortex vibration of cantilever box girder bridge and cantilever box girder

Abstract

The utility model discloses a swing type pneumatic device for controlling vortex vibration of a cantilever box girder bridge and a cantilever box girder. The pneumatic device comprises a hook, a suspension component and a mass block, and the swing type pneumatic devices are arranged on the lower surfaces (3) of cantilevers on the two sides of a cantilever box girder in a bilateral symmetry mode. The cantilever box girder overcomes the defects that a traditional cantilever box girder pneumatic measure is single in acting effect, and practical engineering construction is difficult, formation of vortex at the bottom of the cantilever box girder is disturbed fundamentally, the effect of improving vortex vibration performance of cantilever box girders with different pneumatic shapes is achieved, the vortex vibration amplitude of a main girder is reduced, and the service life of the main girder is prolonged. The driving comfort of the upper portion of the bridge is improved, and the operation safety of the cantilever box girder bridge structure is guaranteed. Compared with a traditional fixed pneumatic measure, the pneumatic measure is more convenient to install and maintain, larger in adjustable range and higher in economical efficiency, and does not conflict with other structures of the bridge.

Description

Technical Field

[0001] This utility model relates to the fields of bridge engineering and disaster prevention engineering, specifically to a swing-type pneumatic device for controlling vortex-induced vibration of cantilever box girder bridges. Background Technology

[0002] Cantilever box girders have long been widely used in high-speed railway bridges and urban municipal bridges in my country due to their convenient construction and superior load-bearing performance. These piers occupy less land, do not affect vehicle traffic below, support a wide bridge deck, and effectively meet the increasing traffic volume on the bridge and the large flow of people and vehicles below, while saving construction land and reducing the number of demolitions required for surrounding residential buildings and structures. However, their blunt-body shape makes the shedding of vortices around the main girder surface under wind loads more pronounced and complex than that of streamlined box girders, resulting in more significant vortex-induced vibration responses in these bridges. Although vortex-induced vibration does not cause catastrophic damage to bridges like flutter or galloping, large-amplitude vortex-induced vibration can affect driving comfort and accelerate the fatigue of bridge components, thus impacting bridge operational safety. Therefore, taking effective aerodynamic measures to control the amplitude of vortex-induced vibration in bridges is of great importance.

[0003] At present, the main measures to improve the vortex-induced vibration performance of cantilever box girder cross sections are to adopt Figure 2 An integral air nozzle (the shaded areas on both sides, i.e., the pointed air nozzles) of the same height as the main beam is used to improve the aerodynamic shape of the main beam cross-section, thereby improving its vortex-induced vibration performance. This type of measure has the disadvantages of high difficulty in the processing and construction of the air nozzles and large steel consumption, which makes the actual engineering construction unchanged and the economic efficiency poor. Utility Model Content

[0004] The purpose of this invention is to provide a swing-type pneumatic device for controlling vortex-induced vibration in cantilever box girder bridges, thus solving the problem of vortex-induced vibration in cantilever box girders. To this end, this invention adopts the following technical solution:

[0005] A swing-type pneumatic device for controlling vortex-induced vibration of a cantilever box girder bridge includes a suspension component, a mass block, and a connecting structure. The lower surfaces of the cantilever sides of the cantilever box girder are symmetrically connected to the suspension component through the connecting structure, and the mass block is suspended by the suspension component to enable the mass block to swing.

[0006] Furthermore, the suspension component can rotate around the hook, with the rotation angle α ranging from 10° to 180°, where the rotation angle α is the angle between the suspension component and the horizontal line.

[0007] Furthermore, the suspension component can be made of rigid rods or flexible structures such as ropes and chains, and its length is 1 / 3 to 2 / 3 of the height of the cantilever box girder. Preferably, it is 1 / 2 times the beam height.

[0008] Further, the length of the hanging member is adjusted according to the cantilever box girder shape.

[0009] Further, the connecting structure is a hook, or a ring, a buckle or other connecting structure suitable for fixing and allowing the hanging member to swing. The fixing structure arranged on the lower bottom surface of the cantilever on both sides of the box girder and matched with the connecting structure can also be a hook or a ring.

[0010] Further, the shape of the mass block includes but is not limited to a square, a cylinder, a cone, a pyramid, and any form of mass block is within the scope of the present patent.

[0011] Further, the pneumatic device is arranged along the bridge axis direction, and the number of the pneumatic devices arranged on each side of the box girder is n, and n is greater than 1.

[0012] The utility model also provides a cantilever box girder, the lower surface (3) of the cantilever on both sides of the cantilever box girder is symmetrically provided with the swing type pneumatic device.

[0013] Compared with the traditional static, fixed and immovable pneumatic measure (such as a wind nozzle in the prior art), the pneumatic measure of the utility model is more convenient to install and maintain, has a larger adjustable range, has better adaptability to cantilever box girders with different sections, is more economical, and will not conflict with other structures of the bridge. Figure 2

[0014] In summary, on the basis of the traditional cantilever box girder, a swingable mass block is hung on the lower side of the cantilever on both sides thereof. In the case of incoming flow wind or bridge self-vibration, the mass block will swing, thereby changing the flow field characteristics of the bottom of the cantilever box girder and fundamentally disrupting the formation of vortexes at the bottom of the cantilever box girder. The pneumatic device can affect the formation, separation and shedding of the vortexes of the cantilever box girder section, reduce the pressure difference between the upper and lower surfaces of the section, eliminate the vortex-induced vibration of the main girder, thereby improving the driving comfort and safety, and to some extent, reducing the bridge fatigue and prolonging the service life of the bridge.

[0015] The utility model will be further described below with reference to the drawings to fully illustrate the purpose, technical features and technical effects of the utility model. DRAWINGS

[0016] Figure 1 It is a standard section view of the existing cantilever box girder section.

[0017] Figure 2 It is a traditional vortex-induced vibration damping measure for the existing cantilever box section.

[0018] Figure 3a It is a schematic view of the swing type pneumatic device of the utility model.

[0019] Figure 3b ​It is the enlarged schematic view of the swing type pneumatic device.

[0020] Figure 4 It is the size and installation position schematic view of the pneumatic device of the embodiment of the utility model, wherein the size unit is cm.

[0021] Figure 5 It is the comparison of the original cantilever beam section and the cantilever beam section of the swing type pneumatic device of the utility model at 0° attack angle vertical vortex vibration amplitude. DETAILED DESCRIPTION

[0022] The technical scheme of the utility model is further described below through specific embodiments. The following embodiments are further illustrations of the utility model, rather than limiting the scope of the utility model.

[0023] Figure 1 、 Figure 3a 、 Figure 3b 、 Figure 4 、 Figure 5 One specific embodiment of the utility model is shown. In the embodiment, the swing type pneumatic device for controlling vortex vibration of the cantilever box girder bridge of the utility model comprises a suspension member 1, a mass block 2 and a hook 4. The suspension member 1 is connected to the hook 4 on the lower surface 3 of the cantilever 101 on both sides of the cantilever box girder 100 in a left-right symmetrical manner, and the mass block 2 is suspended through the suspension member 1. The suspension member 1 can rotate around the hook 4, and the rotation angle α ranges between 10° and 180°. The rotation angle α is the included angle between the suspension member 1 and the horizontal line. The material of the suspension member 1 can be a hard rod or a flexible rope. The length of the suspension member is 1 / 3 to 2 / 3 of the height of the cantilever box girder, and is preferably 1 / 2 of the height of the cantilever box girder. The shape of the mass block 2 is not limited to a square, and any form of mass block is within the scope of the patent.

[0024] The fixed structure 102 matched with the connecting structure is arranged on the lower bottom surface of the cantilever on both sides of the box girder, which can also be a hook, a ring or the like.

[0025] In the specific embodiment, the width of the cantilever box girder, i.e. the width of the bridge, is 25 m, the height of the main girder is 4 m, the suspension member in the swing type pneumatic device is a hard rod with a length of 1 / 2 of the height of the cantilever box girder, i.e. 2 m, the rotatable angle α ranges between 10° and 180°, a square mass block is used, and the cantilevers 101 on each side are arranged along the axis direction of the bridge at intervals of 5 m.

[0026] In the specific embodiment, the pneumatic device for vortex vibration control of the cantilever box girder bridge comprises a suspension member 1, a mass block 2 and a hook 4, which is the same as Figure 2Compared with the conventional wind nozzle measures, the structural form is simpler, the engineering construction and installation are more convenient, and the economy is better.

[0027] Vortex vibration test

[0028] The vortex vibration test result of the cantilever box girder main girder segment model shows that the main girder without any aerodynamic measure occurs obvious vertical vortex vibration at 0° attack angle (as shown in the Figure 5 , wherein the vertical maximum amplitude of the main girder exceeds the allowable amplitude, and there is a vertical vortex vibration zone.

[0029] The test result after the aerodynamic device of the utility model is installed on the main girder is as shown in Figure 5 From Figure 5 , it can be known that the vertical amplitude of the vortex vibration of the segment model is significantly reduced, the vortex vibration phenomenon disappears, and the specification allowable value requirement is met. Figure 4 The specific parameters of the corresponding aerodynamic device are as follows: the suspension component is a hard rod, the length is 2m, the rotatable angle α range is 10°~180°, a square mass block is adopted, and the square mass block is arranged along the bridge axis direction at intervals of 5m.

[0030] Test conclusion: according to the vortex vibration test result of the cantilever box girder main girder segment model, the swing type aerodynamic device composed of the hard rod with the length of 2m and the rotatable angle α range of 10°~180° arranged below the cantilever on both sides can effectively reduce the vertical amplitude of vortex vibration and inhibit the occurrence of vortex vibration response.

[0031] The above describes the preferred embodiment of the utility model in detail. It should be noted that ordinary technical personnel in the art can make many modifications and evolutions according to the concept of the utility model without creative labor. Therefore, any technical solution or technical means obtained by logical analysis, reasoning or limited experiment on the basis of the existing technology according to the concept of the utility model should be within the protection scope determined by the claims.

Claims

1. A swing-type pneumatic device for controlling vortex-induced vibration of cantilever box girder bridges, characterized in that, It includes a suspension component (1), a mass block (2) and a connecting structure; the lower surfaces (3) of the cantilever on both sides of the cantilever box girder are symmetrically connected to the suspension component (1) through the connecting structure, and the mass block (2) is suspended by the suspension component (1) so that the mass block can swing.

2. A swing-type pneumatic device for controlling vortex-induced vibration of a cantilever box girder bridge as described in claim 1, characterized in that, The suspension component (1) can rotate around the hook (4), with the rotation angle α ranging from 10° to 180°. The rotation angle α is the angle between the suspension component and the horizontal line.

3. A swing-type pneumatic device for controlling vortex-induced vibration of a cantilever box girder bridge as described in claim 1, characterized in that, The material of the suspension component (1) can be a rigid rod or a rope with a flexible structure. The length of the suspension component is 1 / 3 to 2 / 3 of the height of the cantilever box girder.

4. A swing-type pneumatic device for controlling vortex-induced vibration of a cantilever box girder bridge as described in claim 1, characterized in that, The connection structure is a hook.

5. A swing-type pneumatic device for controlling vortex-induced vibration of a cantilever box girder bridge as described in claim 1, characterized in that, The pneumatic devices are arranged along the bridge axis, and the number of pneumatic devices arranged on each side of the box girder is n, where n is greater than 1.

6. A cantilever box girder, characterized in that... The swing-type pneumatic device described in claim 1, 2, 3, 4 or 5 is symmetrically arranged on the lower surface (3) of the cantilever on both sides of the cantilever box girder.

Images