Large-span bridge vortex-induced vibration suppression system and method capable of actively changing mass of box girder

Abstract

The invention provides a large-span bridge vortex-induced vibration suppression system and method capable of actively changing the mass of a box girder, and belongs to the technical field of large-span bridge wind resistance. The large-span bridge vortex-induced vibration suppression system comprises a mass changing unit, a power unit and a vibration sensor, and the mass changing unit comprises a liquid storage container arranged in the box girder; the power unit comprises an oil pump which is communicated with the liquid storage container through a main pipeline; the oil pump selects to pump liquid into the liquid storage container or pump out the liquid in the liquid storage container according to the vibration amplitude of the box girder, so that the natural vibration frequency of the box girder is changed by adjusting the weight of the box girder; the vibration sensor is arranged in the box girder and used for monitoring the vibration amplitude of the box girder in real time. The fluid is injected into the liquid storage container, the weight of the box girder is changed, the natural vibration frequency of the box girder is changed, and then the weight and the natural vibration frequency of the bridge are changed, so that the vortex-induced vibration of the large-span bridge is restrained, the risk that the vortex-induced vibration damages the bridge body is avoided, and the service life of the whole bridge is prolonged.

Description

Technical Field

[0001] The present invention belongs to the technical field of wind resistance of large-span bridges, and in particular relates to a system and method for suppressing vortex-induced vibration of large-span bridges by actively changing the mass of box girders. Background Art

[0002] Vortex-induced vibration is a wind-induced vibration phenomenon that occurs in long-span bridges at low wind speeds. Many long-span suspension bridges still produce this type of vibration. In the early design of such long-span bridges, in order to improve their flutter stability, the bridges are generally designed as separated double box beam sections with a central slot. Although this improves the flutter stability, it also increases the possibility of vortex-induced vibration. Although vortex-induced vibration is not divergent, it can still seriously affect the comfort of driving and pedestrians, and can also cause fatigue damage to bridge structural components such as hangers, box beams, and main cables.

[0003] The existing vortex-induced vibration suppression measures are mainly pneumatic suppression measures. Pneumatic measures suppress vortex-induced vibration by adding flow suppressors, guide plates, pneumatic grilles, etc. on the main beam, which has achieved a certain vibration suppression effect, but there are also some outstanding problems: For example, the guide plates, flow suppressors, pneumatic grilles, etc. added by pneumatic measures are exposed to the atmospheric environment, and their durability is difficult to guarantee and difficult to control. The suppression effect is poor and unstable. At the same time, adding these auxiliary facilities on the main beam will also affect the appearance quality of the bridge. Summary of the invention

[0004] An embodiment of the present invention provides a system and method for suppressing vortex-induced vibration of a large-span bridge by actively changing the mass of a box girder. By changing the weight of the box girder to change the natural frequency characteristics of the box girder, the natural frequency of the large-span bridge is changed, thereby achieving the purpose of effectively suppressing the vortex-induced vibration of the box girder.

[0005] In the first aspect, in order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: to provide a vortex-induced vibration suppression system for a large-span bridge that actively changes the mass of the box girder, including: a mass change unit, a power unit and a vibration sensor, the mass change unit includes a liquid storage container arranged in the box girder; the power unit includes an oil pump, and the oil pump is connected to the liquid storage container through a main pipeline; the oil pump selects to pump liquid into the liquid storage container or extract the liquid in the liquid storage container according to the vibration amplitude of the box girder, so as to change its natural frequency by adjusting the weight of the box girder; the vibration sensor is arranged in the box girder, for real-time monitoring the vibration amplitude of the box girder.

[0006] In combination with the first aspect, in one feasible manner, the mass change unit includes a plurality of liquid storage containers evenly distributed along the length direction of the box beam, the plurality of liquid storage containers are connected via branch pipes, and the branch pipes are connected to the main pipe via a main pipe.

[0007] In combination with the first aspect, in one achievable manner, a plurality of liquid storage containers are arranged on a center line in a width direction of the box beam.

[0008] In combination with the first aspect, in one feasible manner, a plurality of the liquid storage containers are arranged in multiple rows along the length direction of the box girder, the main pipeline is arranged along the center line of the width direction of the box girder, each row of the liquid storage containers is symmetrically distributed along the main pipeline, and each row of the liquid storage containers is connected to the main pipeline through respective branch pipes.

[0009] In combination with the first aspect, in one achievable manner, the liquid storage container is fixed to the bottom of the box beam by anchor bolts, and a shock-absorbing rubber pad is provided between the liquid storage container and the box beam.

[0010] In combination with the first aspect, in one achievable manner, the main pipeline is connected to the main pipeline arranged in the box girder via an expansion joint compensator.

[0011] In combination with the first aspect, in one achievable manner, a main control valve is provided on the main pipeline, and a sub-control valve is provided between the branch pipe and the main pipeline.

[0012] In combination with the first aspect, in one achievable manner, a plurality of vibration sensors are distributed in the box girder.

[0013] In a second aspect, an embodiment of the present invention further provides a suppression method, based on a large-span bridge vortex-induced vibration suppression system that actively changes the mass of a box girder, comprising the following steps: Step 1, determining a preset maximum amplitude value and a preset minimum amplitude value allowed for vortex-induced vibration of the target box girder; Step 2: monitor the real-time amplitude value of the target box girder through a vibration sensor. When the real-time amplitude value is greater than or equal to the preset maximum amplitude value of the target box girder, the oil pump is started and pumps fluid into the liquid storage container to change the weight of the box girder and thus change the natural frequency of the box girder; Step 3: when the acquired real-time amplitude value is less than the preset maximum amplitude value of the target box girder, turn off the oil pump and stop injecting fluid into the liquid storage container; Step 4: When the acquired real-time amplitude value is less than the preset minimum amplitude value, the oil pump is started to pump the fluid in the liquid storage container back to the liquid storage tank for recycling.

[0014] Compared with the prior art, the vortex-induced vibration suppression system and method for a large-span bridge that actively changes the box girder mass provided by the present invention has the following beneficial effects: (1) fundamentally changing the natural frequency of the bridge, destroying the prerequisite for the occurrence of vortex-induced vibration; when vortex-induced vibration occurs, the natural frequency of the structure is consistent with the vortex shedding frequency in the incoming wind wake, thereby generating resonance. Therefore, the present invention injects fluid into the liquid storage container, changes the weight of the box girder, and then changes the natural frequency of the large-span bridge. When the natural frequency of the large-span bridge is no longer consistent with the vortex shedding frequency, the vortex-induced vibration of the large-span bridge can be suppressed, thereby improving the stability of the overall structure of the bridge and the comfort of walking, avoiding the risk of vortex-induced vibration causing damage to the bridge body, and improving the overall service life of the bridge. (2) Compared with the conventional pneumatic method, the present invention uses liquid injection to change the deadweight, and can accurately control the weight of the injected liquid through an oil pump, so that the deadweight of the bridge can be accurately changed, thereby accurately changing the natural frequency of the bridge, and improving the suppression effect of vortex-induced vibration. Traditional aerodynamic measures can only qualitatively change the flow field, and the vibration suppression effect cannot be quantitatively described, let alone quantitatively changing the flow field morphology. (3) The main components of this system are installed inside the main beam of the long-span bridge, effectively avoiding the adverse effects of the atmospheric environment (such as precipitation, snowfall, ultraviolet rays, dust particles, and strong winds). Compared with aerodynamic measures, it improves durability and maintainability.

[0015] Compared with the conventional pneumatic method, the present invention adopts the method of injecting liquid to change the deadweight, and can accurately control the weight of the injected liquid through an oil pump, thereby being able to accurately change the deadweight of the bridge, thereby improving the effect of suppressing vortex-induced vibration. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic structural diagram of a vortex-induced vibration suppression system for a large-span bridge that actively changes the mass of a box girder provided in an embodiment of the present invention; Figure 2 A schematic diagram of the transverse cross-sectional layout structure of a large-span bridge vortex-induced vibration suppression system that actively changes the mass of a box girder provided in an embodiment of the present invention; Figure 3 A schematic diagram of the planar layout structure of a large-span bridge vortex-induced vibration suppression system that actively changes the mass of a box girder provided in an embodiment of the present invention within a box girder; Description of reference numerals: 1. Liquid storage container; 2. Vibration sensor; 3. Main pipeline; 4. Oil pump; 5. Main pipeline; 6. Branch pipe. DETAILED DESCRIPTION

[0017] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with 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 intended to limit the present invention.

[0018] Please also read Figures 1 to 3 , the vortex-induced vibration suppression system for a large-span bridge that actively changes the mass of the box girder provided by the present invention is now described. The vortex-induced vibration suppression system for a large-span bridge that actively changes the mass of the box girder comprises: a mass change unit, a power unit and a vibration sensor 2, the mass change unit comprises a liquid storage container 1 arranged in the box girder; the power unit comprises an oil pump 4, and the oil pump 4 is connected to the liquid storage container 1 through a main pipeline 5; the oil pump 4 selects to pump liquid into the liquid storage container 1 or extract the liquid in the liquid storage container 1 according to the vibration amplitude of the box girder, so as to change its natural frequency by adjusting the weight of the box girder; the vibration sensor 2 is arranged in the box girder, and is used to monitor the vibration amplitude of the box girder in real time.

[0019] Compared with the prior art, the vortex-induced vibration suppression system for a large-span bridge that actively changes the box girder mass provided by the present invention has the following beneficial effects: (1) fundamentally changing the natural frequency of the bridge, destroying the prerequisite for the occurrence of vortex-induced vibration. When vortex-induced vibration occurs, the natural frequency of the structure is consistent with the vortex shedding frequency in the wake of the incoming wind, thereby generating resonance. Therefore, the present invention injects fluid into the liquid storage container, changes the weight of the box girder, and then changes the natural frequency of the large-span bridge. When the natural frequency of the large-span bridge is no longer consistent with the vortex shedding frequency, the vortex-induced vibration of the large-span bridge can be suppressed, thereby improving the stability of the overall structure of the bridge and the comfort of walking, avoiding the risk of vortex-induced vibration causing damage to the bridge body, and improving the overall service life of the bridge. (2) Compared with the conventional pneumatic method, the present invention uses liquid injection to change the deadweight, and can accurately control the weight of the injected liquid through an oil pump, so that the deadweight of the bridge can be accurately changed, thereby accurately changing the natural frequency of the bridge, and improving the suppression effect of vortex-induced vibration. Traditional aerodynamic measures can only qualitatively change the flow field, and the vibration suppression effect cannot be quantitatively described, let alone quantitatively changing the flow field morphology. (3) The main components of this system are installed inside the main beam of the long-span bridge, effectively avoiding the adverse effects of the atmospheric environment (such as precipitation, snowfall, ultraviolet rays, dust particles, and strong winds). Compared with aerodynamic measures, it improves durability and maintainability.

[0020] The design principle of the present invention is as follows: the weight of the bridge is changed by changing the mass of the box girder, and the natural vibration frequency of the box girder With mass m and stiffness k, it satisfies:

[0021] When the stiffness k remains unchanged, Inversely proportional to the mass m.

[0022] The prerequisite for vortex-induced vibration is that the natural frequency of the structure is consistent with the vortex shedding frequency. Therefore, the present invention changes the weight of the box girder by injecting liquid into the liquid storage container 1, thereby changing the deadweight of the bridge, so as to adjust the natural frequency of the bridge, so that the natural frequency of the structure is inconsistent with the vortex shedding frequency, and vortex-induced vibration will not occur, and fatigue damage to the bridge will not be caused.

[0023] The present invention suppresses the vortex-induced vibration of the bridge by injecting liquid into the box girder to change the weight of the box girder, thereby changing the deadweight of the bridge. Compared with the conventional pneumatic method, the liquid storage container 1 and the matching pipeline can be hidden in the box girder without being exposed to the atmospheric environment, and the durability is strong. Moreover, by injecting liquid to change the deadweight, the weight of the injected liquid can be accurately controlled by the oil pump 4, and the deadweight of the bridge can also be accurately changed, thereby enhancing the effect of suppressing vortex-induced vibration.

[0024] Since long-span bridges need to be composed of multiple box girders, see Figure 1 In the present application, a liquid storage container 1 is arranged in each box girder, and a pump station can be set up at one end of a long-span bridge. An oil pump 4, an oil storage tank and a control system are set up in the pump station. The vibration sensor 2 is connected to the control system through a data line, and the oil pump 4 is connected to the control system through a data line. According to the vibration data sent back by the vibration sensor 2 in different box girders, it is determined whether the oil pump 4 needs to be started to inject liquid into the corresponding box girder.

[0025] Since different sections of box girders may be subjected to different vortex-induced vibrations, the amount of liquid that needs to be injected is also different. The main pipelines 5 in different box girders are connected in parallel with the main pipeline 3 and are independently controlled by sub-control valves between each main pipeline 5 and the branch pipe 6. The amount of liquid injected into different box girders can be controlled by controlling the opening of the sub-control valves. When the weight of a certain section of the box girder does not need to be adjusted, the sub-control valves in the corresponding box girder can also be controlled to be closed individually, thereby suppressing the vortex-induced vibration of the entire bridge.

[0026] It should be noted that the liquid injected in the present invention can be liquid grease, or water and other non-corrosive fluids; the liquid storage container 1 is made of corrosion-resistant rubber material, resin and other materials, and can also be made of corrosion-resistant metal material.

[0027] The volume of the liquid storage container 1 and the number of liquid storage containers arranged in each box girder can be designed when designing the bridge according to the design type, load, vibration and other data of the bridge. It is necessary to meet the purpose of changing the natural frequency of the bridge weight when the bridge is subjected to the maximum vortex-induced vibration by the volume of the liquid storage container 1, and avoid waste caused by too large a volume of the liquid storage container 1 or too many arrangements.

[0028] In some embodiments, see Figures 1 to 3 The mass change unit includes a plurality of liquid storage containers 1 evenly distributed along the length direction of the box beam, and the plurality of liquid storage containers 1 are connected through branch pipes 6, and the branch pipes 6 are connected to the main pipeline 5. By arranging a plurality of liquid storage containers 1 in the box beam, the force points applied by the liquid storage containers 1 on the box beam are dispersed, so that the box beam is evenly subjected to the gravity of the liquid storage containers 1.

[0029] In some embodiments, see Figures 1 to 3 , multiple liquid storage containers 1 are arranged on the center line of the box girder width direction. In this embodiment, multiple liquid storage containers 1 are evenly spaced along the center line of the box girder. The liquid storage containers 1 are arranged on the center line of the box girder to ensure the consistency between the center of gravity and the center of the bridge, thereby ensuring the overall stability of the bridge.

[0030] Optionally, the liquid storage containers 1 are arranged at both ends of the box beam in the length direction and one is arranged at the center of the gravity and bottom surface of the box beam.

[0031] In some embodiments, see Figures 1 to 3 , multiple liquid storage containers 1 are arranged in multiple rows along the length direction of the box girder, and the main pipeline 5 is arranged along the center line of the width direction of the box girder. Each row of liquid storage containers 1 is symmetrically distributed along the main pipeline 5, and each row of liquid storage containers 1 is connected to the main pipeline 5 through its own branch pipe 6. As shown in the figure, the number of liquid storage containers 1 in each row is an even number such as 2, 4, 6, 8, 10, etc., then the number of liquid storage containers 1 symmetrically arranged along the main pipeline 5 is the same, ensuring the consistency between the center of gravity and the center of the bridge to which it belongs, thereby ensuring the overall stability of the bridge. With such an arrangement, the distance between each oil storage container and the main pipeline 5 will not differ greatly, which facilitates the instantaneous injection of the injected liquid into each oil storage container at the same time, ensuring the overall stability of the bridge.

[0032] See examples Figure 3 The longitudinal spacing of the liquid storage containers 1 inside the box girder is L (in the length direction); the transverse spacings are d0, d1, d2, d3, and d4 (in the width direction).

[0033] Optionally, the number of liquid storage containers 1 arranged in the box girder may be an odd number, such as 3, 5, 7, 9, 11, etc.

[0034] In some embodiments, the liquid storage container 1 is fixed to the bottom of the box beam by anchor bolts, and a shock-absorbing rubber pad is provided between the liquid storage container 1 and the box beam to avoid the risk of damage to the liquid storage container 1 caused by hard contact between the liquid storage container 1 and the box beam during vibration.

[0035] In some embodiments, see Figure 1The power unit also includes a main pipeline 3 connected to the oil pump 4, and the main pipeline 3 is connected to the main pipeline 5 arranged in the box beam through a telescopic compensator. The main pipeline 3 is on the outside of the bridge, connecting the oil pump 4 and the main pipeline 5 in the box beam. Since the main pipeline 3 and the main pipeline 5 in the box beam may be affected by different wind forces and other vibrations, different vibration deformations will occur. The telescopic compensator can absorb and compensate for the different deformations of the two, ensuring the durability of the connection between the two. Similarly, the main pipeline 5 and the branch pipe 6 are connected by a telescopic compensator. In some embodiments, a master control valve (not shown in the figure) is provided on the main pipeline 3, and a sub-control valve is provided between the branch pipe 6 and the main pipeline 5. When each section of the box girder does not need to be injected with liquid, the master control valve can be closed, and when the liquid storage container 1 in some box girders needs to be injected with liquid, or the amount of liquid injected is different, the opening and closing of the sub-control valve can be controlled, thereby more accurately suppressing the vortex-induced vibration of the bridge and improving the service life of the bridge.

[0036] In some embodiments, see Figure 1 and Figure 2 , multiple vibration sensors 2 are distributed in the box girder. Specifically, the vibration sensors 2 are distributed at both ends of the box girder in the length direction; or installed on both sides of the box girder in the width direction, and multiple vibration sensors 2 are evenly arranged along the length direction of the box girder to accurately obtain the vortex-induced vibration of the bridge.

[0037] The vibration sensor 2 is mainly used to measure the vibration frequency and amplitude of an object, and it can convert the vibration signal into an electrical signal for output. The vibration sensor 2 can be divided into different types such as piezoelectric vibration sensor 2, electromagnetic vibration sensor 2 and capacitive vibration sensor 2.

[0038] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0039] Based on the same inventive concept, the embodiment of the present application also provides a method for suppressing vortex-induced vibration of a large-span bridge by actively changing the mass of a box girder, and a system for suppressing vortex-induced vibration of a large-span bridge by actively changing the mass of a box girder, comprising the following steps: Step 1, determining a preset maximum amplitude value and a preset minimum amplitude value allowed for vortex-induced vibration of the target box girder; Step 2: monitor the real-time amplitude value of the target box girder through the vibration sensor 2. When the real-time amplitude value is greater than or equal to the preset maximum amplitude value of the target box girder, the oil pump 4 is started and pumps fluid into the liquid storage container 1 to change the weight of the box girder and thus change the natural frequency of the box girder; Step 3: when the acquired real-time amplitude value is less than the preset maximum amplitude value of the target box girder, the oil pump 4 is turned off to stop injecting fluid into the liquid storage container 1; Step 4: When the acquired real-time amplitude value is less than the preset minimum amplitude value, the oil pump 4 is started to pump the fluid in the liquid storage container 1 back to the liquid storage tank for recycling.

[0040] The present invention achieves real-time monitoring of box girder vibration by arranging a liquid storage container 1 and a vibration sensor 2 inside the box girder, and changes the mass characteristics of the box girder by injecting or extracting liquid in the liquid storage container 1, thereby changing the vibration frequency characteristics of the box girder, and further changing the overall deadweight and natural frequency of the bridge, thereby ultimately achieving the purpose of suppressing vortex-induced vibration of the bridge.

[0041] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A vortex-induced vibration suppression system for a long-span bridge that actively changes the mass of a box girder, characterized in that: include: The mass change unit comprises a liquid storage container (1) arranged in the box beam; The power unit comprises an oil pump (4), the oil pump (4) being connected to the liquid storage container (1) through a main pipeline (3); the oil pump (4) selectively pumping liquid into the liquid storage container (1) or extracting liquid from the liquid storage container (1) according to the vibration amplitude of the box beam, so as to change the natural frequency of the box beam by adjusting the weight of the box beam; and A vibration sensor (2) is arranged in the box beam and is used to monitor the vibration amplitude of the box beam in real time.

2. The vortex-induced vibration suppression system for a large-span bridge that actively changes the mass of a box girder according to claim 1 is characterized in that: The mass change unit comprises a plurality of liquid storage containers (1) uniformly distributed along the length direction of the box beam, the plurality of liquid storage containers (1) are connected to each other via branch pipes (6), and the branch pipes (6) are connected to the main pipe (3) via a main pipe (5).

3. The vortex-induced vibration suppression system for a large-span bridge that actively changes the mass of a box girder according to claim 2 is characterized in that: A plurality of liquid storage containers (1) are arranged on the center line in the width direction of the box beam.

4. The vortex-induced vibration suppression system for a large-span bridge that actively changes the mass of a box girder as claimed in claim 2 is characterized in that: The plurality of liquid storage containers (1) are arranged in multiple rows along the length direction of the box beam, the main pipeline (5) is arranged along the center line of the width direction of the box beam, each row of the liquid storage containers (1) is symmetrically distributed along the main pipeline (5), and each row of the liquid storage containers (1) is connected to the main pipeline (5) through respective branch pipes (6).

5. The vortex-induced vibration suppression system for large-span bridges that actively changes the mass of box beams according to claim 1 is characterized in that: The liquid storage container (1) is fixed to the bottom of the box beam by means of anchor bolts, and a shock-absorbing rubber pad is provided between the liquid storage container (1) and the box beam.

6. The vortex-induced vibration suppression system for a large-span bridge that actively changes the mass of a box girder as claimed in claim 2 is characterized in that: The main pipeline (3) is connected to the main pipeline (5) arranged in the box beam via an expansion joint compensator.

7. The vortex-induced vibration suppression system for a large-span bridge that actively changes the mass of a box girder according to claim 6 is characterized in that: The main pipeline (3) is provided with a main control valve, and a sub-control valve is provided between the branch pipe (6) and the main pipeline (5).

8. The vortex-induced vibration suppression system for a large-span bridge that actively changes the mass of a box girder according to claim 1 is characterized in that: A plurality of vibration sensors (2) are distributed inside the box beam.

9. A method for suppressing vortex-induced vibration of a large-span bridge by actively changing the mass of a box girder, based on the system for suppressing vortex-induced vibration of a large-span bridge by actively changing the mass of a box girder as claimed in any one of claims 1 to 8, characterized in that: The method comprises the following steps: Step 1, determining a preset maximum amplitude value and a preset minimum amplitude value allowed for vortex-induced vibration of the target box girder; Step 2: The real-time amplitude value of the target box girder is monitored by the vibration sensor (2); when the real-time amplitude value is greater than or equal to the preset maximum amplitude value of the target box girder, the oil pump (4) is started and fluid is pumped into the liquid storage container (1), thereby changing the weight of the box girder and thus changing the natural frequency of the box girder; Step 3: when the acquired real-time amplitude value is less than the preset maximum amplitude value of the target box girder, the oil pump (4) is turned off and the injection of fluid into the liquid storage container (1) is stopped; Step 4: When the acquired real-time amplitude value is less than the preset minimum amplitude value, the oil pump (4) is started to pump the fluid in the liquid storage container (1) back to the liquid storage tank for recycling.

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