A pneumatic device for improving vortex vibration performance of split box beam

Abstract

The present invention discloses an aerodynamic device for improving the vortex-induced vibration performance of a split box girder, belonging to the technical field of bridge construction. The device comprises two symmetrically arranged box girders, force guide devices being installed on both sides of the box girders, cross beams being equidistantly arranged between the box girders along the bridge direction, and first aerodynamic measures being provided on both sides of the box girders. The first aerodynamic measures comprise: a vertical skirt and a horizontal spoiler, one end of the horizontal spoiler being connected to the box girder, and one end of the horizontal spoiler being connected to the vertical skirt. The cross beam is connected to a base, and the base is connected to a second aerodynamic measure, the second aerodynamic measure comprising a cross-shaped stabilizing plate, and the second aerodynamic measure being vertically arranged at the lower end of the base. The device aims to solve the problems in existing devices that the actual bridge cannot reduce the vortex-induced vibration amplitude and that, due to the double-width bridge structure, the force on one side is greatly affected when the wind blows on one side, which can easily cause significant damage to the bridge connection.

Description

Technical Field

[0001] The invention belongs to the technical field of bridge construction, and in particular relates to a pneumatic device for improving the vortex vibration performance of a split box girder. Background Art

[0002] With the continuous improvement of bridge theory, the emergence of new materials, and increasing traffic volume, the design spans of bridges are constantly increasing. However, due to the fragility of long-span bridges, wind loads can easily cause vibrations in the bridge section. Common wind-induced vibrations include buffeting, vortex vibration, and flutter. Flutter is a wind-induced vibration that must be avoided in bridge engineering. Split box girders are widely used in long-span bridges due to their excellent flutter stability. However, their vortex vibration performance is less than satisfactory.

[0003] The Chinese patent "A slotted skirt and double-span bridge for improving the vortex vibration performance of a double-span bridge" (publication number: CN113174836 A, publication date: 2021.07.27) discloses a perforated skirt to improve the vortex vibration performance of a double-span bridge. However, its shortcoming is that the patent does not take into account the actual air permeability of the skirt, and is only verified by wind tunnel tests. However, the Reynolds number of the wind tunnel test is very different from that of the actual bridge, and the boundary layer size of the wind tunnel and the actual bridge skirt holes is not necessarily the same, which will result in the actual bridge being unable to reduce the vortex vibration amplitude. And because it is a double-span bridge structure, when the wind blows on one side, the force on one side is greatly affected, which can easily cause greater damage to the bridge connection. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a pneumatic device for improving the vortex-vibration performance of a split box girder, so as to solve the problems in the existing device "a slot skirt and a double-span bridge for improving the vortex-vibration performance of a double-span bridge" in which the actual bridge cannot reduce the vortex-vibration amplitude and because it is a double-span bridge structure, when the wind blows on one side, the force on one side is greatly affected, which easily causes greater damage to the bridge connection.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] The present invention provides an aerodynamic device for improving the vortex-vibration performance of a split box girder, comprising two symmetrically arranged box girders, force guiding devices installed on both sides of the box girders, cross beams equidistantly arranged between the box girders along the bridge direction, first aerodynamic measures provided on both sides of the box girders, the first aerodynamic measures comprising: a vertical skirt and a horizontal spoiler, one end of the horizontal spoiler being connected to the box girder, one end of the horizontal spoiler being connected to the vertical skirt, the cross beam being connected to a base, the base being connected to a second aerodynamic measure, the second aerodynamic measure consisting of a cross-shaped stabilizing plate, and the second aerodynamic measure being vertically arranged at the lower end of the base.

[0007] Furthermore, the force-guiding device includes: a guide plate, an elastic rod, an extension rod, a fixed block and a force-unloading device. The two sides of the box beam are respectively connected to the elastic rod, the elastic rod is connected to the extension rod, the extension rod is connected to the guide plate, a fixed block is installed on the lower side of the box beam, the extension rod passes through the fixed block, the extension rod is connected to the force-unloading device, and the other end of the force-unloading device is connected to another box beam.

[0008] Furthermore, the unloading device includes: a fixed plate, a support rod, an extrusion plate, a force-bearing plate and a spring. The fixed plates have two pieces arranged opposite to each other, the fixed plate is connected to the extension rod, and the other fixed plate is connected to the box beam. Both fixed plates are provided with a slide groove. The support rods have two pieces arranged crosswise between the fixed plates, and one end of the support rod is slidably connected to the slide groove. There are two extrusion plates, and the two extrusion plates are located between the fixed plates. The spring is located between the extrusion plate and the fixed plate. The force-bearing plate is located between the two extrusion plates, and the intersection of the support rods is hinged to the force-bearing plate.

[0009] Furthermore, the extrusion plate and the force-bearing plate are both connected with anti-collision pads.

[0010] Furthermore, through holes are opened on the side surfaces of the two box beams, and fan blades are installed in the through holes, and the fan blades are electrically connected to the motor.

[0011] Furthermore, the base and the second pneumatic means are threadedly connected by high-strength bolts.

[0012] The beneficial effects of the present invention are:

[0013] The present invention provides an aerodynamic device for improving the vortex-vibration performance of a split box girder. Through the first aerodynamic measure and the second aerodynamic measure installed on the box girder, the critical flutter wind speed of the box girder under the two wind attack angle test conditions of -6° and +6° is greater than 58.8m / s; under the three wind attack angle test conditions of 0°, -3°, and +3°, the critical flutter wind speed is greater than 84m / s. As for the vortex-vibration performance, through the first aerodynamic measure and the second aerodynamic measure, the vertical bending vortex-vibration amplitude and the torsional vortex-vibration amplitude of the split box girder are significantly reduced, which greatly improves the vortex-vibration performance of the cross-section. The force-guiding device can transmit the force on one side of the box girder to the other box girder, so that the two box girders are evenly stressed and one side is prevented from being subjected to excessive force; the force-unloading device reduces the influence of wind on the box girder, and can also prevent the box girder from being subjected to excessive impact force when the force-guiding device transmits force to the other box girder; the fan blades in the through-holes provided in the box girder allow the wind to be transmitted out of the box girder, reducing wind resistance.

[0014] Other advantages, objectives and features of the present invention will be described in the following description and will be apparent to those skilled in the art to some extent, or those skilled in the art can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to make the purpose, technical solutions and beneficial effects of the present invention more clear, the present invention provides the following drawings for illustration:

[0016] Figure 1 It is a schematic diagram of the structure of the present invention;

[0017] Figure 2 It is a cross-sectional view of the present invention;

[0018] Figure 3 This is a front view of the second pneumatic measure of the present invention;

[0019] Figure 4 This is an enlarged view of the second pneumatic measure of the present invention;

[0020] Figure 5 It is a cross-sectional view of the force unloading device of the present invention;

[0021] Figure 6 A schematic diagram of a through hole according to the present invention;

[0022] Figure 7 This is a diagram showing the relationship between wind speed and vertical amplitude of a real bridge in the wind tunnel test of the present invention.

[0023] Figure 8 This is a diagram showing the relationship between wind speed and torsional amplitude of a real bridge in the wind tunnel test of the present invention.

[0024] Figure 9 This is a diagram showing the relationship between the reduced wind speed and the torsion angle in the wind tunnel test of the present invention.

[0025] Figure 10 This is a diagram showing the relationship between the reduced wind speed and the vertical reduced amplitude in the wind tunnel test of the present invention.

[0026] Figure 11 This is a relationship diagram between the wind speed and vertical amplitude of the actual bridge under test conditions of different wind attack angles in the wind tunnel test of the present invention.

[0027] Figure 12 This is a relationship diagram between the wind speed and torsional amplitude of the actual bridge under test conditions of different wind attack angles in the wind tunnel test of the present invention.

[0028] Figure 13 This is the streamline diagram around the original section.

[0029] Figure 14 This is a cross-sectional peripheral streamline diagram of the present invention provided with a pneumatic device.

[0030] The markings in the attached figure are as follows: 1. Box girder; 2. First aerodynamic measure; 21. Vertical skirt; 22. Horizontal spoiler; 3. Force guiding device; 31. Elastic rod; 32. Guide plate; 33. Extension rod; 34. Fixed block; 4. Base; 5. Through hole; 6. Second aerodynamic measure; 61. Stabilizing plate; 7. Crossbeam; 8. Unloading device; 81. Support rod; 82. Extrusion plate; 83. Force plate; 84. Spring; 85. Slide; 86. Fixed plate; 9. Anti-collision pad; 10. Fan blade; 11. Motor. DETAILED DESCRIPTION

[0031] like Figures 1 to 14 As shown, the present invention discloses an aerodynamic device for improving the vortex-induced vibration performance of a split box girder. The device comprises two symmetrically arranged box girders 1, each with a force-guiding device 3 mounted on either side. A crossbeam 7 is equidistantly spaced along the longitudinal direction of the bridge between the box girders 1, with multiple crossbeams 7 evenly distributed between the two box girders 1. A first aerodynamic device 2 is mounted on either side of the box girder 1. The first aerodynamic device 2 comprises a vertical skirt 21 and a horizontal spoiler 22. The vertical skirt 21 is 0.75 meters wide, and the horizontal spoiler 22 is 2 meters wide. One end of the horizontal spoiler 22 is connected to the box girder 1, and one end of the horizontal spoiler 22 is connected to the vertical skirt 21. The first aerodynamic device 2 has an L-shaped cross-section. The horizontal spoiler 22 and the vertical skirt 21 extend along the entire length of the box girder 1. The crossbeam 7 is connected to a base 4, which is connected to a second aerodynamic device 6. The base 4 and the second aerodynamic device 6 are threadedly connected using high-strength bolts. The second pneumatic means 6 is composed of a cross-shaped stabilizing plate 61. The width of the horizontal stabilizing plate 61 is set to 2.8 meters, and the width of the vertical stabilizing plate 61 is set to 1.4 meters. The length of the stabilizing plate 61 is the same as that of the box girder 1. The second pneumatic means 6 is vertically installed at the lower end of the base 4.

[0032] The working principle of the above scheme is: the cross-shaped stabilizing plate 61 is set between the upstream and downstream box beams 1, and the L-shaped first aerodynamic measure 2 is set on both sides of the integral box beam 1, which effectively interferes with the vortex shedding between the slots, windward side and wake of the split box beam 1. It can reduce the cross-sectional vortex vibration amplitude without affecting the cross-sectional flutter performance, greatly improve the vortex vibration performance of the split box beam 1, and avoid fatigue damage of bridge components in strong wind environment and affect the service life of the bridge. At the same time, by optimizing the size of the inverted L-shaped first aerodynamic measure 2 (such as Figure 9 、 Figure 10 ), the optimal size of the vertical skirt 21 is obtained. At this point, the vertical bending vortex vibration performance of the box beam 1 is greatly improved. Subsequently, the cross-section torsional performance is further improved by applying the cross-section stabilizer 61 (e.g. Figure 11 、 Figure 12 ) as shown. (As shown in 13, Figure 14(As shown) By using numerical simulation to observe the flow characteristics around the cross-section, it can be clearly observed that: after the first aerodynamic measure 2 and the second aerodynamic measure 6 are installed, the large-scale vortex on the upper surface of the downstream box girder 1 is significantly suppressed, and the overall flow field characteristics are improved, thereby improving the vortex vibration performance of the cross-section.

[0033] The beneficial effects of the above solution are as follows: through the installation of the first aerodynamic measure 2 and the second aerodynamic measure 6 on the box girder 1, the critical flutter wind speed of the box girder 1 under the two wind attack angle test conditions of -6° and +6° is greater than 58.8m / s; under the three wind attack angle test conditions of 0°, -3°, and +3°, the critical flutter wind speed is greater than 84m / s. Regarding vortex-induced vibration performance, the first aerodynamic measure 2 and the second aerodynamic measure 6 significantly reduce the vertical bending vortex-induced vibration amplitude and the torsional vortex-induced vibration amplitude of the split box girder 1, greatly improving the cross-section vortex-induced vibration performance.

[0034] In one embodiment of the present invention, Figures 1 to 6 As shown, the force-guiding device 3 has multiple ones arranged in an opposing and staggered manner. The force-guiding device 3 includes: a guide plate 32, an elastic rod 31, an extension rod 33, a fixed block 34 and a force-removing device 8. The movement length of the elastic rod 31 is greater than the length of the support rod 81. The two sides of the box beam 1 are respectively connected to the elastic rod 31. There are multiple elastic rods 31, each of which is connected to an extension rod 33. There are multiple extension rods 33, and the extension rods 33 are connected to the guide plate 32. A fixed block 34 is installed on the lower side of the box beam 1. The extension rod 33 passes through the fixed block 34, and the extension rod 33 is slidably connected to the fixed block 34. The extension rod 33 is connected to the force-removing device 8, and the other end of the force-removing device 8 is connected to another box beam 1. The force-removing device 8 includes: a fixed plate 86, a support rod 81, an extrusion plate 82, a force-bearing plate 83 and a spring 84. There are two fixed plates 86 arranged in opposition. The fixed plate 86 is connected to the extension rod 33, and the other fixed plate 86 is connected to the box beam 1. Both fixed plates 86 are provided with a slide groove 85. There are two support rods 81 arranged crosswise between the fixed plates 86, and one end of the support rod 81 is slidably connected to the slide groove 85. There are two extrusion plates 82, and the two extrusion plates 82 are located between the fixed plates 86. The spring 84 is located between the extrusion plate 82 and the fixed plate 86. The force plate 83 is located between the two extrusion plates 82, and the intersection of the support rod 81 is hinged to the force plate 83. The extrusion plate 82 and the force plate 83 are both connected with an anti-collision pad 9, and the anti-collision pad 9 is made of elastic material. Through holes 5 are provided on the sides of the two box beams 1, and fan blades 10 are installed in the through holes 5. The fan blades 10 are electrically connected to the motor 11.

[0035] The working principle of the above scheme is: when the wind blows to the side of the box girder 1, the guide plate 32 is forced to move, and the elastic rod 31 retracts. At this time, the extension rod 33 moves toward the unloading device 8, and the fixed plate 86 moves toward the box girder 1 to force the support rod 81 to fold. The extrusion plate 82 moves toward the force-bearing plate 83, and the extrusion plate 82 contacts the anti-collision pad 9 on the force-bearing plate 83, and the spring 84 is compressed. When the wind force decreases or disappears, the elastic rod 31 is no longer under force, and the elastic rod 31 returns to its position. When the wind blows into the through hole 5, the motor 11 can be controlled to rotate to guide the wind out of the through hole 5 to reduce wind resistance. The motor 11 can also be controlled to blow back the wind to achieve a reaction force to reduce the force on the box girder 1.

[0036] The beneficial effects of the above scheme are: the force on one side of the box girder 1 can be transmitted to the other box girder 1 through the force guiding device 3, so that the two box girders 1 are evenly stressed to avoid excessive force on one side; the force unloading device 8 reduces the influence of wind on the box girder 1, and can also avoid the box girder 1 being subjected to excessive impact force when the force guiding device 3 transmits force to the other box girder 1; the fan blades 10 in the through hole 5 opened in the box girder 1 can conduct wind out of the box girder 1, thereby reducing wind resistance.

[0037] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present invention.

Claims

1. A pneumatic device for improving the vortex vibration performance of a split box girder, characterized by: The invention comprises two symmetrically arranged box beams (1), force guide devices (3) are installed on both sides of the box beams (1), cross beams (7) are equidistantly arranged between the box beams (1) along the bridge direction, first aerodynamic measures (2) are provided on both sides of the box beams (1), and the first aerodynamic measures (2) include: a vertical skirt (21) and a horizontal spoiler (22), one end of the horizontal spoiler (22) is connected to the box beam (1), and one end of the horizontal spoiler (22) is connected to the vertical skirt (21), the cross beam (7) is connected to a base (4), and the base (4) A second pneumatic measure (6) is connected, the second pneumatic measure (6) is composed of a cross-shaped stabilizing plate (61), and the second pneumatic measure (6) is vertically arranged at the lower end of the base (4); the force guiding device (3) includes: a guide plate (32), an elastic rod (31), an extension rod (33), a fixed block (34) and a force unloading device (8), the two sides of the box beam (1) are respectively connected to the elastic rod (31), the elastic rod (31) is connected to the extension rod (33), the extension rod (33) is connected to the guide plate (32), and the lower end of the box beam (1) is connected to the elastic rod (31). A fixing block (34) is installed on the side, the extension rod (33) passes through the fixing block (34), the extension rod (33) is connected to the unloading device (8), and the other end of the unloading device (8) is connected to another box beam (1); the unloading device (8) includes: a fixing plate (86), a support rod (81), an extrusion plate (82), a force plate (83) and a spring (84), and the fixing plates (86) are arranged in two opposite directions, the fixing plate (86) is connected to the extension rod (33), and the other fixing plate (86) is connected to the box beam (1). The two fixed plates (86) are both provided with a slide groove (85), the two support rods (81) are cross-arranged between the fixed plates (86), one end of the support rod (81) is slidably connected to the slide groove (85), the two extrusion plates (82) are located between the fixed plates (86), the spring (84) is located between the extrusion plate (82) and the fixed plate (86), the force plate (83) is located between the two extrusion plates (82), and the cross point of the support rod (81) is hinged to the force plate (83).

2. The pneumatic device for improving the vortex vibration performance of a split box beam according to claim 1, characterized in that: The extrusion plate (82) and the force-bearing plate (83) are both connected to an anti-collision pad (9).

3. The pneumatic device for improving the vortex vibration performance of a split box beam according to claim 1, characterized in that: Through holes (5) are provided on the sides of the two box beams (1), fan blades (10) are installed in the through holes (5), and the fan blades (10) are electrically connected to the motor (11).

4. The pneumatic device for improving the vortex vibration performance of a split box beam according to claim 1, characterized in that: The base (4) and the second pneumatic means (6) are connected by high-strength bolt threads.

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