Main girder structure and long-span bridge

Abstract

The invention provides a main beam structure and a long-span bridge, and belongs to the field of wind-induced vibration flow control of main beams of long-span bridges. The problems that the bridge is unstable and the reliability of the damper is insufficient due to dynamic wind load of the large-span bridge are solved. The main beam structure comprises a main beam, a forward bionic scale column and a reverse bionic scale column are arranged on the two sides of the near-ground side end face of the main beam respectively, and the forward bionic scale column and the reverse bionic scale column are used for reducing unsteady aerodynamic force acting on the main beam. The device is mainly used for suppressing the wind-induced vibration of the large-span bridge.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of wind-induced vibration flow control of large-span bridge box girder, and particularly relates to a main girder structure and a large-span bridge. BACKGROUND

[0002] In recent years, with the rapid growth of China's economy and the rapid development of transportation network, the construction of large-span bridges has also entered a new stage. These bridges, with their large span across rivers, valleys and mountains, not only improve the efficiency of transportation, but also become a symbol of modern engineering technology.

[0003] However, as the design span of the bridge increases, the flexibility of the bridge structure also increases, and the decrease of stiffness and damping characteristics significantly increases the sensitivity of the bridge to wind load. Wind load has become one of the most important dynamic loads of large-span bridges, and the influence of wind-induced vibration is increasingly significant. The effect of wind on the bridge not only includes static wind pressure, but also dynamic wind load, which is more likely to cause resonance of the bridge, thereby posing a potential threat to the safety and service life of the bridge. Therefore, how to effectively reduce the wind load and the wind effect caused thereby has become a major challenge for researchers and design engineers. In view of this problem, researchers have carried out a lot of research to explore the wind-induced vibration characteristics and control methods of large-span bridges.

[0004] Active mechanical dampers, as an effective control means, can suppress vibration by increasing the damping of the structure. Devices such as tuned mass dampers and double-frequency tuned mass dampers can effectively reduce the amplitude of wind-induced vibration by adjusting the natural frequency of the bridge so that it does not resonate with the frequency of the wind load. Although these mechanical dampers have good control effect in theory, in practical application, the fatigue and damage of the connecting components often occur, for example, the damper of the Su-Tong Bridge stayed rope has been broken, which has brought hidden dangers to the safety of the bridge. SUMMARY

[0005] Therefore, the present application aims to provide a main girder structure and a large-span bridge to solve the problems of instability of the bridge caused by dynamic wind load and insufficient reliability of the damper.

[0006] To achieve the above-mentioned purpose, the present application adopts the following technical solutions. According to the first aspect of the present application, a main girder structure is provided, comprising: a main girder, the near-ground side end face of the main girder is provided with a positive bionic scale column and a reverse bionic scale column on both sides, wherein the positive bionic scale column and the reverse bionic scale column are used to reduce the unsteady aerodynamic force acting on the main girder.

[0007] Furthermore, the positive bionic scale column and the reverse bionic scale column are both arranged in multiple bionic scale rows along the length direction of the main girder.

[0008] Further, the bionic scale has a hook shape as a whole.

[0009] Further, the bionic scale has a front edge and a curved portion connected to the front edge, and the curved portion is connected to the main beam, wherein the bionic scale is defined as a forward bionic scale when the airflow flows over the front edge of the bionic scale, and vice versa.

[0010] Further, the forward bionic scale row is provided with a plurality of rows in the axial direction, and the reverse bionic scale row is provided with a plurality of rows in the axial direction.

[0011] Further, the spacing D between adjacent forward bionic scale rows is variable, and the spacing D between adjacent reverse bionic scale rows is variable.

[0012] Further, the height h of the forward bionic scale row and the reverse bionic scale row can be the same or different.

[0013] Further, the h is 0.1-0.3 times the height of the main beam.

[0014] Further, the D is 2-4 times the h.

[0015] According to a second aspect of the present application, a large-span bridge is provided, comprising a main beam structure as described above.

[0016] Compared with the prior art, the present application has the following beneficial effects: The main beam structure is simple, the damping principle is clear, the flow separation of the shear layer is inhibited by breaking the uniformity of the airflow, the vortex shedding pattern of the wake flow is changed, the unsteady aerodynamic force acting on the box-shaped main beam is reduced, and the situation that the damper is broken to cause the failure of wind-induced vibration suppression is not prone to occur. BRIEF DESCRIPTION OF DRAWINGS

[0017] The accompanying drawings, which form a part of the present application, are used to provide a further understanding of the present application, and the schematic embodiments of the present application and their descriptions are used to explain the present application, and do not constitute an improper limitation on the present application. In the drawings: Figure 1 is a structural schematic view of a main beam structure according to the present application; Figure 2 is a cross-sectional arrangement view of a bionic scale according to the present application; Figure 3 is a structural schematic view of a forward bionic scale row and a reverse bionic scale row both provided with a plurality of rows according to the present application; Figure 4 is a cross-sectional arrangement view of a bionic multi-row scale; Figure 5 is a transient vortex diagram of a box-shaped main beam without control measures; Figure 6 Box girder turbulent kinetic energy map without control measures; Figure 7 Box girder transient vorticity map with bionic scale control; Figure 8 Box girder turbulent kinetic energy map with bionic scale control.

[0018] Girder 1; forward bionic scale row 2; reverse bionic scale row 3. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict, and the described embodiments are only part of the embodiments of the present application, not all the embodiments.

[0020] It should be noted that the descriptions of "left", "right", "left side", "right side", "upper", "lower", "top", "bottom" and the like in the present application are all defined based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and are not intended to indicate or imply that the described structure must be constructed and operated in a particular orientation, therefore, it cannot be understood as a limitation on the present application. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified and limited.

[0021] In the description of the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be directly connected, or indirectly connected through an intermediate medium, or the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0022] With reference to the accompanying drawings, according to the first aspect of the present application, a girder structure is provided, comprising: a girder 1, specifically a box girder, which can also be provided in other forms according to actual conditions, and a forward bionic scale row 2 and a reverse bionic scale row 3 are arranged on both sides of the near-ground end face of the box girder, wherein the forward bionic scale row 2 and the reverse bionic scale row 3 are used to reduce the unsteady aerodynamic force acting on the box girder. The structure of the box girder is not limited to the box structure, and other structures can also be provided according to actual conditions, and the structures that need to suppress wind-induced vibration can also use the improved form. The forward bionic scale row 2 and the reverse bionic scale row 3 are arranged in multiple bionic scale rows along the length direction of the box girder. Based on the discovery that the shark scale has a great drag reduction effect on the movement of the shark, the overall shape of the bionic scale is set to be the same as the hook-shaped shark scale. The bionic scale has a leading edge and a curved portion connected to the leading edge, and the curved portion is connected to the box girder, wherein the forward bionic scale 2 is defined when the flow passes through the leading edge of the bionic scale, and the reverse bionic scale 3 is defined. When the airflow passes through, no matter which direction the flow comes from, the uniformity can be broken under the action of the forward and reverse bionic scales, the flow separation of the shear layer is suppressed, and the vortex shedding mode of the wake flow is changed. Thus, the wind-induced vibration effect is suppressed, and the probability of structural fatigue damage is reduced. As for the forward bionic scale row 2 and the reverse bionic scale row 3, the structure strength is met, and at the same time, rust prevention treatment is needed to make it have a longer service time and more reliable service performance in a humid environment.

[0023] In the present embodiment, the forward bionic scale row 2 is provided with several rows in the axial direction, and the reverse bionic scale row 3 is provided with several rows in the axial direction. This arrangement can help to break the uniformity of the airflow flow for two or more times, strengthen the inhibition of the unsteady aerodynamic force, thereby prolong the effective service time, and make the bridge have a more stable performance in use.

[0024] In the embodiment, the spacing D between adjacent forward bionic scale rows 2 is variable, and the spacing D between adjacent reverse bionic scale rows 3 is variable. The height h of the forward bionic scale rows 2 and the reverse bionic scale rows 3 can be the same or different. The h is 0.1-0.3 times the height of the box girder, and the D is 2-4 times the h. Through the above parameter setting mode, on the one hand, the resistance of airflow flowing through can be reduced, and the strong local vibration of the beam structure can be prevented; and at the same time, through reasonable parameter setting, a relatively optimal wind-induced vibration suppression effect can be formed, and the waste of materials and the excessive increase of processing cost can be avoided. As for the processing and installation mode of the bionic scales, reasonable selection can be made according to actual conditions, for example, the forward bionic scale rows 2 and the reverse bionic scale rows 3 can be processed in an integral forming mode, and then connected with the box girder through bolts and the like. The bionic scales can also be arranged in a single form and connected with the box girder through bolts, and then corresponding structures matched with the bolts are arranged on the box girder to fix the bionic scales.

[0025] The flow field measurement technology is used to perform undisturbed measurement on the wake flow field of the uncontrolled box girder. Figure 5 and Figure 6 The vortex and the time-averaged TKE statistical results of the wake flow field are shown in Figs. 6 and 7. Figure 5 It can be known from Fig. 6 that the vortexes in the wake flow of the box girder without control measures present an alternating shedding, which can produce a periodic aerodynamic force acting on the box girder, and cause the wind-induced vibration of the box girder. Figure 6 It can be known from Fig. 7 that the TKE distribution range in the wake flow of the box girder is relatively large, and the numerical value is relatively high, and the unsteady aerodynamic force acting on the box girder is relatively large.

[0026] Figure 7 and Figure 8 The vortex diagram and the time-averaged TKE statistical results of the wake flow of the box girder after the bionic scales are installed are shown in Figs. 8 and 9. Figure 5 and Figure 7 It is found that the alternating vortex shedding is changed into symmetrical shedding under the control of the bionic scales, at this time, the periodic vortex shedding is suppressed, and the unsteady aerodynamic force is significantly reduced. Figure 6 and Figure 8 It can be known from Figs. 8 and 9 that the TKE distribution range and the maximum amplitude of the box girder under the control of the bionic scales are significantly reduced. The comprehensive analysis shows that the unsteady aerodynamic force acting on the box girder can be effectively reduced by the bionic scales, and the control target of reducing the wind-induced vibration of the box girder can be achieved.

[0027] According to another aspect of the present application, a large-span bridge is provided, which comprises a girder structure as described above. The bionic scale structure is used to help the large-span bridge to suppress the wind-induced vibration, and prolong the service life.

[0028] The above disclosed embodiments of the present application are only used to help explain the present application. The embodiments do not describe all the details of the present application, and the present application is not limited to the specific embodiments described. According to the content of the present specification, many modifications and changes can be made. The present specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present application, so that those skilled in the art can well understand and utilize the present application.

Claims

1. A girder structure, characterized by, The application relates to a main beam structure. The main beam (1) is provided with a forward bionic scale array (2) and a reverse bionic scale array (3) on the two sides of the near-ground side end face respectively, wherein the forward bionic scale array (2) and the reverse bionic scale array (3) are used for reducing the unsteady aerodynamic force acting on the main beam (1).

2. A girder structure according to claim 1, wherein: The forward bionic scale array (2) and the reverse bionic scale array (3) are arranged in multiple bionic scale arrays along the length direction of the main beam (1).

3. A girder structure according to claim 2, wherein: The bionic scale has a whole hook shape.

4. A girder structure according to claim 3, wherein: The bionic scale has a front edge and a bending part connected with the front edge, and the bending part is connected with the main beam (1), wherein the forward bionic scale (2) is defined when the airflow flows through the front edge of the bionic scale, and the reverse bionic scale (3) is defined conversely.

5. A girder structure according to claim 1, 2, 3 or 4, characterised in that: The forward bionic scale array (2) is provided with a plurality of rows in the axial direction, and the reverse bionic scale array (3) is provided with a plurality of rows in the axial direction.

6. A girder structure according to claim 5, wherein: The interval D between adjacent forward bionic scale arrays (2) is variable, and the interval D between adjacent reverse bionic scale arrays (3) is variable.

7. A girder structure according to claim 6, wherein: The height h of the forward bionic scale array (2) and the reverse bionic scale array (3) can be the same or different.

8. A girder structure according to claim 7, wherein: The h is 0.1-0.3 times the height of the main beam (1).

9. A girder structure according to claim 8, wherein: The D is 2-4 times the h.

10. A long span bridge characterized by: The application further relates to a main beam structure comprising the main beam structure as claimed in claim 1, 2, 3, 4, 6, 7, 8 or 9.

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