CN112681106B - An aerodynamic structure for suppressing wind-induced vibration of steel arch bridges - Google Patents

Abstract

The invention discloses a pneumatic structure for inhibiting wind-induced vibration of a steel arch bridge, which comprises a plurality of air deflector units arranged on the bottom surface of an arch rib at intervals and a ventilation guardrail continuously arranged on the top surface of the arch rib. Adopt this device can disturb respectively through the air current swirl of arch rib top and below, can reduce simultaneously again because of setting up the too big influence of wind load that aviation baffle unit and guardrail produced, improve the structural security, the ventilation guardrail still enough regards as patrolling and examining the way handrail, is favorable to guaranteeing personnel's safety of patrolling and examining, moreover, because the different structures are adopted to the upper and lower side of arch rib, can also lead to the upper and lower air current that regeneration to have very big asynchronism, reduce the possibility that wind-induced vibration takes place, the control of the vertical wind vibration of specially adapted large-span steel arch rib structure, the security of construction stage bridge has been effectively guaranteed, can avoid again because the cost that applys the attenuator and bring increases the problem, can continue to restrain the wind vibration in the operation stage, has important spreading value.

Description

An Aerodynamic Structure for Suppressing Wind-induced Vibration of Steel Arch Bridges

technical field

The invention relates to the technical field of aerodynamic structures of arch bridges, in particular to an aerodynamic structure for restraining wind-induced vibration of steel arch bridges.

Background technique

With the substantial improvement of material properties and construction and manufacturing equipment, the span of bridges is constantly breaking new records. The arch bridge is beautiful in shape and easy to assemble and transport. It is one of the preferred bridge types when crossing ravines and rivers. Arch rib is an important force-bearing structure of arch bridge, and its cross section is generally rectangular or quasi-rectangular. The structural cross section is relatively passivated and has poor wind resistance stability. This cross section will experience wind-induced vibration under certain conditions, which may be possible during construction and operation. appears, which will seriously affect the safety and normal use of bridge construction. Compared with concrete arch bridges, steel arch bridges can achieve larger spans, but the damping ratio of steel bridges is small and the structure is more flexible, which will make steel arch bridges extremely sensitive to wind.

In order to improve the blunt body section of rectangular or quasi-rectangular arch ribs, the current conventional method is:

1) Set the chamfer for the rectangular section. Through chamfering, the section is slightly aerodynamically smoothed, and the separation point of the airflow at the sharp corner is divided into two parts to reduce the possibility of vortex formation.

2) The arch ribs are inward/outwardly inclined. By sloping the arch rib, the incoming flow and the arch rib section form a certain angle, reducing the possibility of the vertical vertical rectangular section forming a fixed vortex shedding.

3) A corrugated plate is set above the arch rib. This method is suitable for middle-supported and bottom-supported arch bridges. The air flow of the arch rib is compressed by the corrugated plate to accelerate the airflow velocity, disturb the vortex shedding of the original arch rib, and achieve the effect of limiting the vortex excitation common amplitude value of the arch rib.

The above scheme improves the wind resistance stability of the arch bridge to a certain extent and reduces the possibility of wind vibration, but there are still the following shortcomings:

1) The chamfered structure of rectangular section is changed from quadrilateral to hexagonal or octagonal or quasi-rectangular with arc. The structure is complex, the construction is inconvenient, and the cost of bridge construction is greatly increased. Existing engineering examples show that the chamfered rectangular section still has the possibility of wind vibration, and the chamfering cannot completely change its passivated aerodynamic shape.

2) The arch ribs are inward/outwardly inclined. This method complicates the stress on the structural space and increases the difficulty of construction. However, for railway bridges with narrow widths, especially the top-loaded railway bridges, the inclination angle is limited.

3) A corrugated plate is set above the arch rib. There are too many connecting members between the corrugated plate and the arch rib, and it is impossible to set up an inspection channel above the arch rib.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the difficulty of the improvement measures in the prior art to easily and effectively solve the problem of poor wind resistance stability of steel arch bridges, especially top-loaded arch bridges, so that wind-induced vibration may seriously affect the safety of the bridge in the construction stage and the operation stage. To overcome the above-mentioned deficiencies, an aerodynamic structure for suppressing wind-induced vibration of a steel arch bridge is provided.

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

An aerodynamic structure for suppressing wind-induced vibration of a steel arch bridge comprises several air deflector units arranged at intervals on the bottom surface of an arch rib and ventilation guardrails continuously arranged on the top surface of the arch rib.

By adopting the aerodynamic structure for suppressing wind-induced vibration of a steel arch bridge according to the present invention, the air flow passing under the arch rib is guided outside the arch rib by the wind deflector unit arranged on the arch rib bottom plate. , disrupt the vortex under the arch rib, and use the ventilation guardrail arranged on the top plate of the arch rib to disrupt the airflow vortex above the arch rib, and at the same time reduce the problem of excessive wind load caused by the setting of the guardrail, Improve the lateral stability of the structure, the ventilation guardrail can also be used as the handrail of the inspection road, which is conducive to ensuring the safety of the inspection personnel. Furthermore, because the upper and lower parts of the arch ribs adopt different structures, not only can the original arches be disrupted respectively. The regular vortex airflow of the rib structure can also lead to great asynchrony in the regenerated upper and lower airflows, reducing the possibility of wind-induced vibration to a greater extent. From the perspective of structural wind engineering, the application adopts aerodynamic structures to achieve the purpose of drainage, diversion and turbulence, and is especially suitable for the control of vertical wind vibration of large-span steel arch rib structures. The most controlled stage is the vertical vibration of the arch rib during the construction stage. Therefore, the present application has a simple structure, which can effectively solve the problem of the construction safety of the long-span arch bridge caused by the wind vibration caused by the current arch rib construction not fully considered, effectively guaranteeing The safety of the bridge construction stage can also avoid the problem of increasing the cost caused by the application of dampers, and it can continue to suppress wind vibration during the operation stage, especially for the top-loaded arch bridge structure, which has important promotion value.

Preferably, the wind deflector unit includes two vertical plates and a transverse plate connected between the two vertical plates, the vertical plates are arranged along the transverse bridge direction, and the thickness direction of the transverse plates is along the Vertical setting.

The above setting method is adopted, that is, the thickness side of the vertical plate and the horizontal plate are both facing the windward surface, and there are ventilation channels between the vertical plate and the horizontal plate, so as to reduce the windward area as much as possible, and hardly increase the arch ribs. It can effectively guide the incoming flow passing under the arch rib to the outside of the underside of the arch rib, so that the arch rib bottom plate cannot form a regular vortex, and effectively suppress the wind-induced vibration.

Further preferably, the wind deflector unit is arranged on the side of the bottom surface of the arch rib close to the outer side.

That is, the wind deflector unit is arranged closer to the windward side of the corresponding arch rib, which is beneficial to guide the airflow after passing through the separation point at the lower part of the windward side of the arch rib to be away from the lower side of the arch rib as soon as possible.

Further preferably, the angle at which the outer side of the vertical plate is inclined outward is greater than the angle at which the inner side thereof is inclined outward, the bottom surface of the outer side of the vertical plate is higher than the bottom surface of the inner side thereof, and the vertical plate is connected to the arch rib. The width of one end is smaller than the width of the end remote from the arch rib.

The above-mentioned setting method is adopted, that is, the wind deflector unit is inclined to the outside of the arch rib, and the transverse plate is inclined so that the air outlet of the wind deflector unit is far away from the arch rib, reducing the impact on the arch rib. Wind loads and improved lateral stability. At the same time, the vortex that may be generated after the air flow is separated is kept away from the arch rib, and at the same time, the width of one end connecting the arch rib is small, which is beneficial to reduce the width of the welding surface and reduce the welding workload.

Further preferably, the height of the vertical plate is 0.1-0.3 times the height of the arch rib, the width of the edge of the vertical plate is 0.2-0.3 times the width of the arch rib, and the width of the lower edge is the arch rib. 0.3-0.4 times the width of the rib, and the distance between the two vertical plates of the wind deflector unit is 1-1.1 times the width of the arch rib.

Further preferably, the transverse plate is a flat plate or an arc plate, the length of the transverse plate is 1.1-1.2 times the distance between the corresponding two vertical plates, and the width of the transverse plate is corresponding to the lower part of the vertical plate. 1.1-1.3 times the width of the rim.

The length of the transverse plate is the longitudinal bridge direction, the width of the transverse plate is the transverse bridge direction, and the four sides of the transverse plate are all beyond the corresponding vertical plate, which can be delayed under the arch rib after the airflow separation. The re-attachment point of the edge is also convenient for construction and welding. The arc panel is used because the surface is irregular, and the airflow is less likely to form a regular vortex, which further reduces the possibility of wind-induced vibration.

Further preferably, the air deflector unit is 5-10 cm away from the outer edge of the arch rib, and the center-to-center distance between two adjacent air deflector units is 2-3 times the width of the air deflector unit.

Further preferably, the wind deflector units are distributed between 1/4-3/4 of the span of the arch rib.

That is, the wind deflector unit is arranged at a position other than 1/4 of the arch feet on both sides, which is closer to the bottom of the pier, with strong restraint and less wind-induced vibration, which is conducive to further reducing the construction cost, reducing the weight of the bridge, and reducing the processing time. , Installation difficulty.

Preferably, the ventilation guardrail comprises a wind deflector, a vertical bar and a horizontal bar, the horizontal bar is distributed on the upper part, the middle part and the lower part of the vertical bar, and the wind deflector is located on the horizontal bar of the middle part and the lower part. between the rods.

The above setting method is adopted, that is, the upper and lower sides of the windshield of the ventilation guardrail are ventilated, which is conducive to reducing the windshield area formed by the installation of the guardrail, effectively reducing the overall wind load of the arch rib, and reducing the cost at the same time. Lose weight.

Further preferably, the ventilation guardrails are provided on both sides of the top surface of each arch rib, the cross section of the ventilation guardrail is an arc structure, and the distance between the two ventilation guardrails gradually decreases from bottom to top.

That is, the ventilation guardrails on both sides are in the form of arc inner wrapping, which is beneficial to compress the width of the inspection lane, stabilize the pedestrian walking area, and ensure the safety of the inspection personnel.

To sum up, compared with the prior art, the beneficial effects of the present invention are:

1. The use of the aerodynamic structure for suppressing the wind-induced vibration of the steel arch bridge according to the present invention can disturb the airflow vortex passing above and below the arch rib respectively, and at the same time, it can reduce the excessive wind load caused by the setting of the wind deflector unit and the guardrail. The ventilation guardrail can also be used as the handrail of the inspection road, which is conducive to ensuring the safety of the inspection personnel. Moreover, because the upper and lower parts of the arch ribs adopt different structures, it can also lead to regeneration. The resulting upper and lower airflows have great asynchrony, reducing the possibility of wind-induced vibration, especially for the control of vertical wind vibration of large-span steel arch-rib structures, which not only effectively ensures the safety of the bridge during construction, but also reduces the possibility of wind-induced vibration. It avoids the problem of increased cost caused by the application of dampers, and can continue to suppress wind vibration in the operation stage, especially for the top-loaded arch bridge structure, which has important promotion value.

2. Minimize the windward area increased due to the addition of aerodynamic measures, reduce the overall wind load of the arch rib, reduce the lateral stability problem, further reduce the cost, reduce the weight of the bridge, and reduce the difficulty of processing and installation.

3. It is beneficial to compress the width of the inspection road, stabilize the pedestrian walking area, and ensure the safety of the inspection personnel.

Description of drawings:

1 is a schematic cross-sectional view of a pneumatic structure for suppressing wind-induced vibration of a steel arch bridge described in the present invention;

2 is a schematic elevational view of a pneumatic structure for suppressing wind-induced vibration of a steel arch bridge described in the present invention;

3 is a schematic structural diagram of the air deflector unit in Embodiment 1;

4 is a schematic diagram of the layout of the aerodynamic structure for suppressing wind-induced vibration of a steel arch bridge described in the present invention;

5 is a schematic structural diagram 1 of the air deflector unit in Embodiment 2;

FIG. 6 is a second structural schematic diagram of the air deflector unit in Embodiment 2. FIG.

Marked in the figure: 1-arch rib, 2-wind deflector unit, 21-vertical plate, 22-transverse plate, 3-ventilation guardrail, 31-wind deflector, 32-vertical bar, 33-crossbar.

Detailed ways

The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. However, it should not be construed that the scope of the above-mentioned subject matter of the present invention is limited to the following embodiments, and all technologies realized based on the content of the present invention belong to the scope of the present invention.

Example 1

The aerodynamic structure for suppressing wind-induced vibration of a steel arch bridge according to the present invention includes several air deflector units 2 arranged at intervals on the bottom surface of the arch rib 1 and ventilation guardrails 3 continuously arranged on the top surface of the arch rib 1 .

Specifically, as shown in Figures 1-3, the figures show the cross-sections of the two arch ribs 1, a cross brace is connected between the two arch ribs 1, and the guide ribs 1 are arranged on the bottom plate of the arch rib 1. The wind panel unit 2 is used to guide the airflow passing under the arch rib out of the arch rib 1 to disrupt the vortex under the arch rib 1 . The wind deflector unit 2 includes two vertical plates 21 and a transverse plate 22 connected between the two vertical plates 21. The vertical plates 21 are arranged along the transverse bridge direction. The thickness direction is arranged vertically, and there is a ventilation channel in the middle of the wind deflector unit 2, that is, the vertical plate 21 and the horizontal plate 22 are both facing the windward side of the thickness side, so as to reduce the windward area as much as possible, that is, hardly increase the The windward area of the arch rib 1 effectively guides the incoming flow passing under the arch rib 1 to the outside of the underside of the arch rib 1, so that the bottom plate of the arch rib 1 cannot form regular vortices and effectively suppresses wind-induced vibration.

As shown in FIG. 1 , the wind deflector unit 2 is arranged on the side of the bottom surface of the arch rib 1 close to the outer side, which is beneficial to guide the airflow after passing through the separation point at the lower part of the windward side of the arch rib to the lower side of the arch rib as soon as possible. , such as the wind deflector unit 2 is 5-10 cm away from the outer edge of the arch rib 1 .

Preferably, the distance between the centers of two adjacent wind deflector units 2 is 2-3 times the width of the wind deflector units 2 , and the distribution of the wind deflector units 2 on the arch rib 1 is based on actual The situation is determined, the arch feet on both sides are close to the pier bottom, the restraint is strong, and wind-induced vibration is not easy to occur. Preferably, the wind deflector units 2 are distributed between 1/4-3/4 of the span of the arch rib 1. As shown in Figure 4, the wind deflector unit 2 is arranged at a position other than 1/4 of the arch feet on both sides, which is conducive to further reducing the cost, reducing the weight of the bridge, and reducing the difficulty of processing and installation.

As shown in FIG. 3 , the angle of the outward inclination of the outer side of the vertical plate 21 is greater than the angle of the outward inclination of the inner side thereof, and the width of the end of the vertical plate 21 connected to the arch rib 1 is smaller than that of the end away from the arch rib 1 The width of the vertical plate 21 is 0.1-0.3 times the height of the arch rib 1, the width of the upper edge of the vertical plate 21 is 0.2-0.3 times the width of the arch rib 1, and the width of the lower edge is The width of the arch rib 1 is 0.3-0.4 times, and the distance between the two vertical plates 21 of the wind deflector unit 2 is 1-1.1 times the width of the arch rib 1 . The bottom surface of the outer side surface of the vertical plate 21 is higher than the bottom surface of the inner side surface. The horizontal plate 22 is a flat plate, which is inclined upward from the inside to the outside, that is, the side close to the windward side is higher, which is conducive to keeping the airflow away from the arch ribs 1. Bottom plate, the length of the horizontal plate 22 along the bridge direction is 1.1-1.2 times the distance corresponding to the two vertical plates 21, and the horizontal bridge width of the horizontal plate 22 is corresponding to the width of the lower edge of the vertical plate 21. 1.1-1.3 times, the horizontal plate 22 extends out of the corresponding vertical plate 21 in both the length and width directions. With the above arrangement, the re-attachment point on the lower edge of the arch rib 1 after the airflow separation can be delayed, reducing The wind load on the small arch rib 1 improves the lateral stability. At the same time, the vortex that may be generated after the separation of the air flow is kept away from the arch rib 1, and the width of one end connecting the arch rib is small, which is beneficial to reduce the width of the welding surface and reduce the welding workload.

The ventilation guardrail 3 is arranged along the entire length of the arch rib 1. The ventilation guardrail 3 includes a wind deflector 31, a vertical bar 32 and a cross bar 33. The wind deflector 31 is located in the middle of the vertical bar 32, such as The transverse rods 33 are distributed on the upper, middle and lower parts of the vertical rods 32 , and the wind deflector 31 is located between the transverse rods 33 in the middle and lower parts, as shown in FIG. 2 , namely, the baffles The upper and lower sides of the wind panel 31 are ventilated, which is beneficial to reduce the wind blocking area formed by the setting of the guardrail, effectively reduce the overall wind load of the arch rib, and at the same time reduce the cost and weight. Of course, the positions of the wind deflector 31 and the ventilation place can also be interchanged. The number and position of the cross bars 33 can also be adjusted according to design requirements.

The ventilation guardrails 3 are provided on both sides of the top surface of each arch rib 1. The cross section of the ventilation guardrails 3 is an arc structure. Referring to FIG. 1, the distance between the two ventilation guardrails 3 is from bottom to top. Gradually reducing, that is, the ventilation guardrails on both sides are in the form of arc inner wrapping, which is beneficial to compress the width of the inspection road, stabilize the pedestrian walking area, and ensure the safety of inspection personnel.

The use of the aerodynamic structure for suppressing the wind-induced vibration of the steel arch bridge according to the present invention can not only disturb the airflow vortex passing above and below the arch rib, but also reduce the excessive wind load caused by the setting of the wind deflector unit and the guardrail. The impact of the rib can be improved, and the structural safety can be improved. The ventilation guardrail can also be used as the handrail of the inspection road, which is conducive to ensuring the safety of the inspection personnel. Moreover, because the upper and lower parts of the arch rib adopt different structures, it can also lead to regeneration. The upper and lower airflows have great asynchronous anisotropy, which can significantly reduce wind-induced vibration. It is especially suitable for the control of vertical wind vibration of large-span steel arch rib structures, which not only effectively ensures the safety of the bridge during construction, but also avoids the The problem of increased construction cost caused by the application of dampers can continue to suppress wind vibration during the operation stage, and there is no limit to the type of arch bridges, which has important promotion value.

Example 2

The aerodynamic structure for suppressing wind-induced vibration of a steel arch bridge according to the present invention is substantially the same as that of Embodiment 1, except that the transverse plate 22 can also be replaced with an arc panel. The arc panel is used, because of its irregular surface, the airflow is less likely to form regular vortices, which further reduces the possibility of wind-induced vibration.

As shown in FIG. 5 , the concave surface of the transverse plate 22 faces the arch rib 1 ; as shown in FIG. 6 , the convex surface of the transverse plate 22 faces the arch rib 1 .

The above descriptions are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included in the protection of the present invention. within the range.

Claims (9)

1. The utility model provides an restrain pneumatic structure of steel arch bridge wind-induced vibration, its characterized in that contains the interval and sets up in a plurality of aviation baffle unit (2) of arch rib (1) bottom surface and set up in succession in ventilation guardrail (3) of arch rib (1) top surface, aviation baffle unit (2) contain two vertical board (21) and connect in two horizontal board (22) between vertical board (21), vertical board (21) are to setting up along the cross bridge, the thickness direction of horizontal board (22) is along vertical setting, the angle that vertical board (21) lateral surface leaned out is greater than its inboard angle that leans out, the outside bottom surface of vertical board (21) is higher than its inboard bottom surface, ventilation guardrail (3) contain deep bead (31).

2. A pneumatic structure for suppressing wind-induced vibration of a steel arch bridge according to claim 1, wherein the air deflector unit (2) is disposed on the outer side of the bottom surface of the arch rib (1).

3. A pneumatic structure for suppressing wind induced vibrations in steel arch bridges as claimed in claim 2, wherein the width of said vertical plate (21) at the end connecting said arch rib (1) is smaller than the width at the end remote from said arch rib (1).

4. A pneumatic structure for suppressing wind-induced vibration of a steel arch bridge according to claim 3, wherein the height of the vertical plate (21) is 0.1-0.3 times of the height of the arch rib (1), the width of the upper edge of the vertical plate (21) is 0.2-0.3 times of the width of the arch rib (1), the width of the lower edge of the vertical plate (21) is 0.3-0.4 times of the width of the arch rib (1), and the distance between the two vertical plates (21) of the air deflector unit (2) is 1-1.1 times of the width of the arch rib (1).

5. A pneumatic structure for suppressing wind-induced vibration of a steel arch bridge according to claim 4, wherein the transverse plates (22) are flat plates or cambered plates, the length of the transverse plates (22) is 1.1-1.2 times the distance between the two corresponding vertical plates (21), and the width of the transverse plates (22) is 1.1-1.3 times the width of the lower edges of the corresponding vertical plates (21).

6. The pneumatic structure for inhibiting the wind-induced vibration of the steel arch bridge according to claim 2, wherein the distance between the air deflector units (2) and the outer edge of the arch rib (1) is 5-10cm, and the distance between the centers of two adjacent air deflector units (2) is 2-3 times of the width of the air deflector units (2).

7. A pneumatic structure for suppressing wind induced vibration of a steel arch bridge according to claim 1, wherein the air deflector units (2) are distributed between 1/4-3/4 of the span of the arch rib (1).

8. A pneumatic structure for suppressing the wind-induced vibration of a steel arch bridge according to any one of claims 1 to 7, wherein the ventilation fence (3) further comprises vertical bars (32) and cross bars (33), the cross bars (33) are distributed on the upper part, the middle part and the lower part of the vertical bars (32), and the wind shields (31) are positioned between the cross bars (33) on the middle part and the lower part.

9. The pneumatic structure for inhibiting the wind-induced vibration of the steel arch bridge according to claim 8, wherein the ventilation guardrails (3) are arranged on two sides of the top surface of each arch rib (1), the cross section of each ventilation guardrail (3) is of an arc structure, and the distance between the two ventilation guardrails (3) is gradually reduced from bottom to top.

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