A pneumatic structure for controlling vortex-induced vibration of double-deck truss bridges

Abstract

This invention discloses a control aerodynamic structure for vortex-induced vibration of a double-layer truss bridge, relating to the field of bridge engineering technology. It includes two vibration damping units, each fixed to the outside of the lower chord. Each damping unit comprises: a longitudinal drainage pipe fixed along its length to the outside of the lower chord of the double-layer truss stiffening beam; a horizontal plate fixed horizontally along the bridge direction to the lower edge of the water pipe and the outer edge of the lower chord; several drainage system maintenance access railings composed of posts and high-strength steel wires; several vertical drainage pipes on the bridge deck connected to the longitudinal drainage pipes at intervals along the bridge direction; longitudinal drainage pipe baffles tightly attached to the outer edge of the longitudinal drainage pipes, with their lower edges fixed to the horizontal plate; several longitudinal drainage pipe baffle stiffening ribs fixed to the longitudinal drainage pipe baffles and the horizontal plate at intervals along the bridge direction; several longitudinal stiffening ribs of the horizontal plate arranged along its length below the horizontal plate to increase its stiffness; and several transverse stiffening ribs of the horizontal plate arranged at intervals below the horizontal plate to increase its stiffness. The aerodynamic structure involved in this invention can effectively suppress the vortex-induced vibration amplitude of double-layer truss bridges, improve driving comfort and safety, and help extend the service life of the bridge.

Description

Technical Field

[0001] The invention belongs to the technical field of bridge engineering, and in particular relates to a pneumatic structure for controlling vortex-induced vibration of a double-layer truss bridge. Background Art

[0002] With the development of economy and the increase of traffic demand, bridges are developing in the direction of large span and lightness. Truss bridges are light in structure, adaptable to a wide range of spans, require less steel, and are easy to construct and fast in construction. Double-layer trusses have the basic advantages of trusses. At the same time, because the upper and lower decks are both driving lanes, the traffic volume is large, and the requirements of increased traffic demand can be well met. Therefore, they have broad application prospects in bridge construction. Existing research is mostly focused on the flutter stability of trusses, and there are fewer studies on the vortex-vibration performance of double-layer truss bridges. The damping of large-span bridges is relatively low, and the problem of wind-induced vibration is more prominent. The vortex-vibration phenomenon occurs in large-span double-layer truss bridges, which will affect the safety and comfort of bridge driving and cause fatigue damage to the bridge structure. Therefore, it is very necessary to invent a device that can effectively improve the vortex-vibration stability of double-layer truss bridges without affecting their flutter performance. In addition, the control pneumatic structure involved in the present invention can be combined with a drainage system, does not require complex mechanical devices and continuous power supply, is easy to use and has low cost. This passive control measure is more needed in actual engineering. Summary of the invention

[0003] In view of this, an object of the present invention is to provide an aerodynamic structure for controlling vortex-induced vibration of a double-deck truss bridge, so as to solve the problem of wind-induced vibration of the double-deck truss bridge.

[0004] In order to achieve the above object, the present invention provides the following technical solutions:

[0005] The present invention discloses a control pneumatic structure for vortex-induced vibration of a double-layer truss bridge, comprising two vibration suppression units, wherein the control pneumatic structure is respectively arranged at the lower chord of the left side and the right side of the double-layer truss, and the vibration suppression unit comprises a bridge-oriented drainage pipe, a horizontal plate, a dry drainage system maintenance channel guardrail, a plurality of bridge deck vertical drainage pipes, a bridge-oriented drainage pipe baffle, a plurality of bridge-oriented drainage pipe baffle stiffening ribs, a plurality of horizontal plate longitudinal stiffening ribs, and a plurality of horizontal plate transverse stiffening ribs;

[0006] The along-bridge drainage pipe is fixed on the outside of the lower chord rod throughout its length, the horizontal plate is fixed horizontally along the along-bridge direction to the lower edge of the water pipe and the outer edge of the lower chord rod, the several drainage system maintenance channel guardrails are arranged on the outer edge of the horizontal plate, the several vertical drainage pipes on the bridge deck are connected to the along-bridge drainage pipe at a certain distance along the bridge direction, the along-bridge drainage pipe baffle is close to the outer edge of the along-bridge drainage pipe, and the lower edge is fixed to the horizontal plate, the several along-bridge drainage pipe baffle stiffening ribs, the along-bridge drainage pipe baffle and the horizontal plate are fixed at a certain distance along the bridge direction, the several horizontal plate longitudinal stiffening ribs are arranged below the horizontal plate throughout its length, the dry horizontal plate transverse stiffening ribs are arranged below the horizontal plate at intervals.

[0007] The working principle of this technical solution is:

[0008] By installing a controlled aerodynamic structure on the outside of the lower chord, the drainage needs of the bridge deck system are taken into account. On the basis of saving steel, the aerodynamic shape of the original double-layer truss section is changed, and the aerodynamic stability of the section is improved, thereby ensuring the vortex-vibration performance of the section without changing the original good flutter performance of the section.

[0009] Furthermore, the width of the horizontal plate is B, B = (0.02-0.03) L, L is the width of the bridge, and a 10 mm thick steel plate is used, which is welded to the outside of the lower chord. The position can be appropriately adjusted according to the dynamic characteristics of the bridge, and it also provides a support platform for the drainage pipe along the bridge.

[0010] Furthermore, the diameter of the drainage pipe along the bridge can be adjusted according to the rainfall at the bridge site, but the maximum shall not exceed 0.6 times the width of the horizontal plate. The pipe shall be made of PVC pipe with a thickness of 10 mm and shall be fixed to the horizontal plate with clips at a certain distance along the bridge.

[0011] Furthermore, the several drainage system maintenance channel guardrails are vertically fixed on the outside of the horizontal plate and are composed of columns and high-strength steel wires. The spacing between the columns is consistent with the spacing between the maintenance channel guardrails. The column height is 1.2m, and the interval between the railing crossbars is 0.2m. High-strength steel wire with a diameter of 5mm is used, and the top crossbar uses high-strength steel wire with a diameter of 16mm. The air permeability can be fine-tuned, and it is recommended to be 80%-90%. The establishment of the drainage system maintenance channel guardrails ensures the safety of maintenance operations during the bridge operation period.

[0012] Furthermore, the diameters of the several vertical drainage pipes on the bridge deck and the spacing along the bridge can be adjusted according to the rainfall at the bridge site. The pipes use PVC pipes with a thickness of 10 mm. The spacing distance along the bridge is recommended to be half the length of the double-layer truss internode. The upper edge is connected to the bridge deck drainage system, and the lower edge is connected to the drainage pipe along the bridge.

[0013] Furthermore, the bridge-directed drainage pipe baffle is vertically fixed on the upper surface of the horizontal plate by welding, and is connected to the water pipe on the side. On the one hand, it limits the lateral displacement of the water pipe, and at the same time increases the rigidity of the horizontal plate. It is recommended to use a steel plate with a thickness of 10 mm, and the height of the baffle is recommended not to exceed three quarters of the diameter of the bridge-directed drainage pipe.

[0014] Furthermore, the stiffening ribs of the drainage pipe baffle along the bridge are spaced a certain distance along the bridge and are welded to the drainage pipe baffle along the bridge and the horizontal plate. The material is recommended to be a steel plate with a thickness of 10 mm. The spacing along the bridge is recommended to be one-eighth of the inter-section length, thereby improving the rigidity of the drainage pipe baffle along the bridge.

[0015] Furthermore, the stiffening ribs of the horizontal plate are fixed vertically to the horizontal plate by welding, and are arranged at intervals in the transverse direction or along the bridge. The interval distance can be adjusted appropriately according to the width of the horizontal plate. The longitudinal stiffening ribs of the horizontal plate are arranged throughout the length, and the transverse stiffening ribs of the horizontal plate are arranged at a certain interval in the transverse direction. The material is recommended to be a steel plate with a thickness of 10 mm. The interval of the transverse stiffening ribs of the horizontal plate in the along-bridge direction is recommended to be one-eighth of the length of the segment, and the interval of the longitudinal stiffening ribs of the horizontal plate in the along-bridge direction is recommended to be one-quarter of the length of the horizontal plate. The height of the stiffening ribs can be adjusted appropriately, and it is recommended not to exceed the distance between the horizontal plate and the lower edge of the lower chord. The stiffening ribs in two directions increase the stiffness of the horizontal plate.

[0016] The beneficial effects of the present invention are:

[0017] (1) This technical solution can provide a support platform for the original drainage pipe, and based on the structural requirements and wind resistance stability, it can save steel to the greatest extent; (2) Passive control measures are adopted, and no additional complex mechanical measures and continuous power supply are required, saving the cost of subsequent operation and maintenance; (3) The control pneumatic structure disclosed in the present invention simply changes the aerodynamic shape of the double-layer truss, but significantly improves the vortex-vibration stability of the section and maintains the flutter stability of the section.

[0018] 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 may be taught from the practice of the present invention. The objectives and other advantages of the present invention may be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to make the purpose, technical solution and beneficial effects of the present invention clearer, the present invention provides the following drawings for illustration:

[0020] Figure 1 It is a schematic plan view of a double-deck truss bridge of the present invention;

[0021] Figure 2is a three-dimensional schematic diagram of a double-deck truss bridge of the present invention;

[0022] Figure 3 It is a plan view schematic diagram of the control pneumatic structure of the present invention;

[0023] Figure 4 A three-dimensional schematic diagram of a pneumatic control structure of the present invention;

[0024] Figure 5 The graph is a graph of the vertical displacement of the double-layer truss without the control aerodynamic structure installed at various attack angles;

[0025] Figure 6 is a curve diagram of the torsional displacement of the double-layer truss without the control aerodynamic structure installed at various attack angles;

[0026] Figure 7 A graph showing the vertical displacement of the double-layer truss at various attack angles for installing the control aerodynamic structure;

[0027] Figure 8 A graph showing the vertical displacement of the double-layer truss at various attack angles for installing the control aerodynamic structure;

[0028] The following are marked in the accompanying drawings:

[0029] 1. Drainage pipe along the bridge; 2. Horizontal plate; 3. Guardrail of the drainage system maintenance passage; 4. Vertical drainage pipe on the bridge deck; 5. Baffle plate for drainage pipe along the bridge; 6. Stiffening ribs of baffle plate for drainage pipe along the bridge; 7. Longitudinal stiffening rib one of the horizontal plate; 8. Longitudinal stiffening rib two of the horizontal plate; 9. Longitudinal stiffening rib three of the horizontal plate; 10. Transverse stiffening ribs of the horizontal plate. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the present invention more clear, the following is further described in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention, that is, the embodiments described are only part of the embodiments of the present invention, not all embodiments.

[0031] The components described and shown in the drawings and embodiments of the present invention may be arranged and designed in various configurations. Therefore, the detailed description of the embodiments of the present invention provided in the following drawings is not intended to limit the scope of the claimed invention, but merely represents a selected embodiment of the present invention. Based on the drawings and embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0032] The features and performances of the present invention are further described in detail below in conjunction with the embodiments.

[0033] As shown in Figure 3, the present invention provides a control pneumatic structure for vortex-induced vibration of a double-layer truss bridge, including several spliced ​​control pneumatic structures, wherein the pneumatic control structure is arranged at the outer edge of the lower chord, welded to the lower chord, and the welding position is below the middle of the lower chord. For different double-layer truss bridges, the position can be appropriately adjusted according to the height, width, inter-node distance of the double-layer truss and the need for bridge deck drainage. It includes two vibration suppression units, which are respectively fixed on the outer sides of the left and right lower chords of the double-layer truss, and each vibration suppression unit includes a bridge-oriented drainage pipe 1, a horizontal plate 2, several drainage system maintenance channel guardrails 3, several bridge deck vertical drainage pipes 4, a bridge-oriented drainage pipe baffle 5, several bridge-oriented drainage pipe baffle stiffening ribs 6, several horizontal plate longitudinal stiffening ribs 7 to 9, and several horizontal plate transverse stiffening ribs 10. The horizontal plate 2 is fixed on the outside of the lower chord, the drain pipe 1 is fixed next to the outside of the lower chord and fixed on the upper surface of the lower horizontal plate, the several drainage system maintenance channel guardrails 3 are fixed on the outer edge of the horizontal plate, the several vertical drain pipes 4 on the bridge deck are arranged at intervals along the bridge direction, connecting the bridge deck drainage and the drain pipes along the bridge direction, the drain pipe baffles 5 along the bridge direction are tightly attached to the drain pipes along the bridge direction, and are vertically fixed on the upper surface of the horizontal plate 2, the several drain pipe baffle stiffening ribs 6 along the bridge direction are fixed to the horizontal plate 2 and the drain pipe baffles 5 along the bridge direction, the several horizontal plate longitudinal stiffening ribs 7 to 9 are fixed to the lower surface of the horizontal plate 2 at a certain distance in the transverse direction of the bridge, and the several horizontal plate transverse stiffening ribs 10 are fixed to the horizontal plate 2 and the horizontal plate longitudinal stiffening ribs 7 to 9 at a certain distance in the transverse direction of the bridge.

[0034] Figure 1 It is a schematic structural plan view of a double-layer truss stiffening beam according to a specific embodiment of the present invention. Other structures of the double-layer truss can also be seen from the figure, such as inner and outer anti-collision guardrails, bridge deck, bridge deck stiffening ribs, and maintenance road guardrails.

[0035] Figure 2 The figure is a schematic diagram of the structure of a double-layer truss stiffening rib according to a specific embodiment of the present invention. From the figure, it can be clearly seen that the components of the double-layer truss stiffening beam are arranged in the transverse and longitudinal directions of the bridge. Figure 1 Further supplementary expansion.

[0036] Figure 4 It is a three-dimensional schematic diagram of a control aerodynamic structure for vortex-induced vibration of a double-deck truss bridge disclosed in the present invention. From the figure, one can see the spatial arrangement of the along-bridge drainage pipe, horizontal plates, several drainage system maintenance channel guardrails, several bridge deck vertical drainage pipes, along-bridge drainage pipe baffles, several along-bridge drainage pipe baffle stiffening ribs, and several horizontal plate stiffening ribs.

[0037] Vortex vibration test

[0038] The vortex vibration test results of the double-layer truss segment model show that the double-layer truss without controlled aerodynamic structure has obvious vertical bending vortex vibration ( Figure 5 shown) and torsional vortex vibration ( Figure 6 As shown in the figure, at a wind attack angle of 0°, the maximum vertical displacement of the double-layer truss far exceeds the allowable displacement. At wind attack angles of 0° and ±3°, the torsional displacement is close to or exceeds the specification limit. At the same time, there are two vortex-oscillation ranges for both vertical bending and torsion.

[0039] The test results after installing the control pneumatic structure of the present invention on the double-layer truss are as follows: Figure 7-Figure 8 As shown, from Figure 7 It can be seen that the vertical displacement of the vortex-induced vibration of the segment model is significantly reduced. Although the vertical bending has a slightly larger displacement in the high wind speed range at 0° attack angle, it is still within the specification range. Figure 8 It can be seen that the vortex-induced vibration torsional displacement of the segment model is significantly reduced. Before the wind speed of 30m / s, there is almost no vibration. Although there is torsional displacement after 30m / s, the bridge has been closed at this time and has no impact on driving safety.

[0040] Flutter test

[0041] It can be seen from Table 1 that, for the original section of the double-layer truss at wind attack angles of 0°, ±3°, and ±5°, the critical flutter wind speed is greater than the flutter test wind speed, and the flutter stability meets the requirements. After the control aerodynamic measures described in the present invention are set, the critical flutter wind speed is still greater than the flutter test wind speed, and the flutter stability still meets the requirements.

[0042] Table 1: Flutter test results

[0043]

[0044] Conclusion

[0045] According to the wind tunnel test results of the segment model vibration measurement of the double-layer truss, the control aerodynamic measures of the present invention are set on the double-layer truss, which can significantly improve the stability. At the same time, the control aerodynamic measures of the present invention will not affect the vortex vibration performance of the double-layer truss, and can be easily matched with the drainage system.

[0046] The above is a detailed description of an embodiment of the present invention, but the content is only a preferred embodiment of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A pneumatic structure for controlling vortex-induced vibration of a double-layer truss bridge, arranged outside the lower chord of the bridge, characterized in that: It comprises two vibration suppression units, each of which comprises a drainage pipe along the bridge (1), a horizontal plate (2), a plurality of drainage system maintenance channel guardrails (3), a plurality of vertical drainage pipes on the bridge deck (4), a baffle plate along the bridge drainage pipe (5), a plurality of baffle plate stiffening ribs along the bridge drainage pipe (6), a first longitudinal stiffening rib of the horizontal plate (7), a second longitudinal stiffening rib of the horizontal plate (8), a third longitudinal stiffening rib of the horizontal plate (9), and a plurality of transverse stiffening ribs of the horizontal plate (10); The bridge-side drainage pipe (1) is laterally fixed to the lower chord, and the lower edge is fixed to the horizontal plate (2); the horizontal plate (2) is arranged along the entire length of the bridge, the inner side is fixed to the outer edge of the lower chord, and the upper surface is fixed to the bridge-side drainage pipe (1); a plurality of drainage system maintenance channel guardrails (3) are vertically fixed to the outer side of the horizontal plate (2), and are composed of columns and high-strength steel wires. The spacing between the columns and the maintenance channel guardrails is kept uniform, and the column height and the high-strength steel wire diameter are adjusted according to actual needs; a plurality of bridge deck vertical drainage pipes (4) are arranged at a certain distance along the bridge, the upper edge is connected to the bridge deck drainage channel, and the lower edge is connected to the bridge-side drainage pipe (1), and the spacing distance is adjusted according to the rainfall in the area where the bridge is located; the bridge-side drainage pipes (4) are arranged at a certain distance along the bridge, the upper edge is connected to the bridge deck drainage channel, and the lower edge is connected to the bridge-side drainage pipe (1), and the spacing distance is adjusted according to the rainfall in the area where the bridge is located; The inner side of the pipe baffle (5) is tightly attached to the drainage pipe (1) along the bridge direction, perpendicular to the horizontal plate (2), and the lower edge is fixedly connected thereto; a plurality of the said drainage pipe baffle stiffening ribs (6) along the bridge direction are spaced a certain distance in the bridge direction, and are fixed to the drainage pipe baffle (5) along the bridge direction and the horizontal plate (2); the said horizontal plate longitudinal stiffening rib one (7), the said horizontal plate longitudinal stiffening rib two (8) and the said horizontal plate longitudinal stiffening rib three (9) are spaced a certain distance in the transverse direction, and are arranged under the horizontal plate (2); a plurality of the said horizontal plate transverse stiffening ribs (10) are spaced a certain distance in the bridge direction, and are arranged under the horizontal plate (2); the drainage pipe baffle (5) along the bridge direction is vertically fixed to the upper surface of the horizontal plate (2) by welding, and the side surface is connected to the water pipe.

2. The aerodynamic structure for controlling vortex-induced vibration of a double-deck truss bridge according to claim 1, characterized in that: The upper and lower layers of the double-layer trusses are both driving lanes, and the bridge deck is reinforced with plate beams.

3. The aerodynamic structure for controlling vortex-induced vibration of a double-deck truss bridge according to claim 1, characterized in that: The control pneumatic structure combines the aerodynamic shape with the requirements of the bridge drainage system. The main structure is a combination of a drainage pipe (1) along the bridge and a horizontal plate (2). The remaining structures are all guarantee structures for ensuring the rigidity of the main structure and the safety of bridge maintenance during operation.

4. The aerodynamic structure for controlling vortex-induced vibration of a double-deck truss bridge according to claim 3, characterized in that: The width of the horizontal plate (2) in the main structure is B, B = (0.02-0.03) L, L is the width of the bridge, and is welded to the outer side of the lower chord.

5. The aerodynamic structure for controlling vortex-induced vibration of a double-deck truss bridge according to claim 3, characterized in that: The diameter of the drainage pipe (1) along the bridge in the main structure is adjusted according to the rainfall at the bridge site, but the maximum does not exceed 0.6 times the width of the horizontal plate (2). The drainage pipe (1) along the bridge is fixed to the horizontal plate at a certain distance by buckles.

6. The aerodynamic structure for controlling vortex-induced vibration of a double-deck truss bridge according to claim 1, characterized in that: A plurality of drainage system maintenance channel guardrails (3) are vertically fixed on the outside of the horizontal plate (2), and are composed of columns and high-strength steel wires. The spacing between the columns is consistent with the spacing between the maintenance channel guardrails. The column height is 1.2m, and the interval between the railing crossbars is 0.2m. High-strength steel wires with a diameter of 5mm are used, and the top crossbars use high-strength steel wires with a diameter of 16mm.

7. The aerodynamic structure for controlling vortex-induced vibration of a double-deck truss bridge according to claim 1, characterized in that: The diameters of a plurality of vertical drainage pipes (4) on the bridge deck are adjusted according to the rainfall at the bridge site.

8. The aerodynamic structure for controlling vortex-induced vibration of a double-deck truss bridge according to claim 1, characterized in that: The stiffening ribs (6) of the drainage pipe baffle along the bridge are spaced a certain distance along the bridge and are welded to the drainage pipe baffle along the bridge (5) and the horizontal plate (2), so as to improve the rigidity of the drainage pipe baffle along the bridge (5).

9. The aerodynamic structure for controlling vortex-induced vibration of a double-deck truss bridge according to claim 1, characterized in that: The horizontal plate longitudinal stiffening rib one (7), the horizontal plate longitudinal stiffening rib two (8), the horizontal plate longitudinal stiffening rib three (9), and a plurality of horizontal plate transverse stiffening ribs (10) are all fixed vertically to the horizontal plate (2) by welding, and are arranged at intervals in the transverse direction or along the bridge direction, wherein the horizontal plate longitudinal stiffening rib one (7), the horizontal plate longitudinal stiffening rib two (8), the horizontal plate longitudinal stiffening rib three (9), and a plurality of horizontal plate transverse stiffening ribs (10) are arranged throughout the length, and a plurality of horizontal plate transverse stiffening ribs (10) are arranged at certain intervals in the transverse direction.

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