Inertial bridge transverse dynamic deflection measuring device and method

Abstract

An inertial bridge transverse dynamic deflection measuring device, comprising a housing (1), springs (2), a mass block (3), a first limiting mechanism, and a displacement meter (4). The mass block (3) is located in the housing (1); one end of each the pair of springs (2) is symmetrically fixed to opposite ends of the mass block (3), the other ends of the springs (2) are fixed to the inner wall of the housing (1); one of side end plates of the housing (1) connected to the springs (2) is provided with a through hole, and a test end of the displacement meter (4) measures the relative displacement of the mass block (3) and the housing (1) by means of the through hole; and the first limiting mechanism is used for counteracting the total gravity of the mass block (3) and magnets arranged on the first limiting mechanism. Further provided is an inertial bridge transverse dynamic deflection measuring method. The measuring device and method can adapt to direct tests of transverse dynamic deflection of main beams having different transverse dynamic deflection precision requirements of bridges having different spans, and have high measurement precision, fast and efficient installation and arrangement, simple structural form, good natural environment adaptability and economy, etc.

Description

Inertial bridge transverse dynamic deflection measuring device and method TECHNICAL FIELD

[0001] The present application relates to the field of bridge girder transverse dynamic deflection testing, in particular to an inertial bridge transverse dynamic deflection measuring method and device. BACKGROUND

[0002] Bridge girder transverse dynamic deflection reflects the degree of transverse dynamic bending deformation of the girder under the action of wind, vehicles, crowds, seismic motion and other external loads, and has a significant impact on pedestrian comfort, bridge service life and safety, especially the most intuitive parameter of transverse vibration behavior of long-span pedestrian bridges. Accurate and efficient acquisition of bridge girder transverse dynamic deflection has become one of the important problems that need to be concerned in bridge engineering. Accurate measurement of bridge girder transverse dynamic deflection helps to evaluate the walking comfort, structural health and safety performance of the bridge. The commonly used methods for measuring bridge girder transverse dynamic deflection include direct measurement method and indirect measurement method, such as Beidou system and GPS used in super-long span bridges, graphic method and table displacement meter method used in small and medium span bridges, etc. The acceleration method and the inclinometer method are indirect measurement methods. The measurement accuracy of existing various technical methods is independent of the dynamic deflection of the bridge structure. After the equipment is produced, the accuracy is a certain value, and it cannot adapt to the different needs of large displacement value and small displacement value for accuracy. In addition, Beidou system and GPS require no obstruction at the measurement point, complex technology and high price. The image acquisition equipment used in the graphic method is difficult to adapt to the adverse effects of rain, snow, fog and foundation vibration in the environment, and the safety protection problem of the equipment itself in the long-term monitoring process is difficult to effectively solve. The good lens is also expensive, and it is difficult to effectively measure when crossing large rivers, valleys and mountainous areas. The table displacement meter has high precision and low price, but it needs fixed reference points during testing, which greatly limits its use. Indirect measurement methods are to obtain the dynamic deflection value through complex mathematical operations after obtaining other physical quantity values. The data itself error and the actual boundary conditions in data processing are difficult to accurately count, and the experience property is obvious, resulting in the accuracy of the results is not ideal. In recent years, the microwave radar method has been in the research stage, and its practical value is limited, and the price is extremely expensive. The fixed reference point for transverse dynamic deflection testing is difficult to determine.

[0003] By the end of 2023, there are 10239 extra-large bridges in China. With the improvement of urbanization level and the development of traffic construction, the number of footbridges increases year by year. Especially in recent years, the demand for urban landscape makes the footbridge increasingly complex and super span. The cross-vibration of such large-span bridges brings about the problems of traffic comfort, structural durability and safety; and it is necessary to accurately and efficiently obtain the cross-vibration displacement of the bridge.

[0004] Therefore, it is necessary to provide a bridge transverse deflection measurement method and device to accurately and quickly obtain the transverse deflection of the beam body, which is a technical problem to be solved. SUMMARY

[0005] An object of the present application is to solve at least the above problems and provide at least the advantages to be described later.

[0006] Another object of the present application is to provide a direct testing method and device for the transverse deflection of the main beam, which can be self-adapted to different span bridges with different transverse deflection accuracy requirements, and has the advantages of quick and efficient installation and layout, good structure and natural environment adaptability, good economy and the like.

[0007] The technical scheme adopted by the present application to solve the technical problem is: an inertia type bridge transverse deflection measuring device, comprising a shell, a spring, a mass block, a first limiting mechanism and a displacement meter.

[0008] The mass block is located in the shell, one end of a pair of springs is symmetrically fixed to both ends of the mass block, the other end of the spring is fixed to the inner wall of the shell, one side end plate of the shell connected with the spring is provided with a through hole, the displacement meter testing end measures the relative displacement amount of the mass block and the shell through the through hole, and the first limiting mechanism is used to offset the gravity of the mass block.

[0009] As a further scheme of the present application, the mass block is a hollow structure.

[0010] As a further scheme of the present application, the top plate of the shell is made of conductive material, thereby providing a suitable damping ratio.

[0011] As a further scheme of the present application, it further comprises a power supply assembly and a data transmission module; the power supply assembly is electrically connected with the displacement meter and continuously supplies power to the displacement meter, and the data transmission module is electrically connected with the displacement meter and saves and transmits the measured data, thereby realizing automatic measurement.

[0012] As a further scheme of the present application, the first limiting mechanism comprises a first magnet and a second magnet, the first magnet is fixed to the bottom of the shell, the second magnet is fixed to the bottom of the mass block, the first magnet and the second magnet have the same magnetic pole, and the repulsion magnetic force between the first magnet and the second magnet is equal to the total gravity of the mass block and the magnet arranged on the mass block.

[0013] As a further scheme of the present application, the first limiting mechanism comprises a first magnet and a second magnet, the first magnet is fixed to the bottom of the shell, the second magnet is fixed to the bottom of the mass block, the first magnet and the second magnet have the same magnetic pole, and the repulsion magnetic force between the first magnet and the second magnet is equal to the total gravity of the mass block and the magnet arranged on the mass block.

[0014] As a further scheme of the present application, the first limiting mechanism comprises a first magnet and a second magnet, the first magnet is fixed to the bottom of the shell, the second magnet is fixed to the bottom of the mass block, the first magnet and the second magnet have the same magnetic pole, and the repulsion magnetic force between the first magnet and the second magnet is equal to the total gravity of the mass block and the magnet arranged on the mass block.

[0015] As a further scheme of the present application, the first limiting mechanism comprises a first magnet and a second magnet, the first magnet is fixed to the bottom of the shell, the second magnet is fixed to the bottom of the mass block, the first magnet and the second magnet have the same magnetic pole, and the repulsion magnetic force between the first magnet and the second magnet is equal to the total gravity of the mass block and the magnet arranged on the mass block.

[0016] As a further scheme of the present application, the first limiting mechanism comprises a first magnet and a second magnet, the first magnet is fixed to the bottom of the shell, the second magnet is fixed to the bottom of the mass block, the first magnet and the second magnet have the same magnetic pole, and the repulsion magnetic force between the first magnet and the second magnet is equal to the total gravity of the mass block and the magnet arranged on the mass block.

[0017] The present application also provides a method for using the inertia type bridge transverse dynamic deflection measuring device.

[0018] S1, fixing the measuring device on a bridge beam to be measured, so that the axis direction of the spring is parallel to the transverse direction of the beam;

[0019] S2, recording the transverse displacement of the mass block measured by the displacement meter, which is the bridge transverse dynamic deflection.

[0020] The present application has at least the following advantages: the classical theory of the inertia type displacement meter shows that when the frequency ratio (the frequency of the structure to be measured / the frequency of the device itself) is greater than 2.5 and the damping ratio is 0.6-0.7, the measured value of the displacement of the structure to be measured is basically equal to the actual value, and the displacement test precision increases with the increase of the frequency ratio. Therefore, an inertia type bridge transverse dynamic deflection measuring method and device are provided, the change amount of the mass block relative to the shell is the displacement value of the structure to be measured, which is directly measured by the displacement meter arranged at the end, and the device can be made portable and small in size through structural design.

[0021] Other advantages, objects and features of the present application will be apparent to those skilled in the art from the following description, and will be understood by those skilled in the art through study and practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a schematic diagram of the structure of an inertial bridge transverse dynamic deflection measuring device according to an embodiment of the present application;

[0023] Figure 2 is a side view of an inertial bridge transverse dynamic deflection measuring device according to an embodiment of the present application;

[0024] Figure 3 is a schematic diagram of the establishment of a coordinate system for an inertial bridge transverse dynamic deflection measuring device.

[0025] Wherein, 1 - shell, 2 - spring, 3 - mass, 4 - displacement meter, 5 - power supply assembly, 6 - data transmission module, 7 - first magnet, 8 - second magnet, 9 - third magnet, 10 - fourth magnet. DETAILED DESCRIPTION

[0026] The present application will be described in detail below with reference to the drawings. Those skilled in the art will be able to implement the present application based on these descriptions. Before the present application is described in detail with reference to the drawings, it should be specifically pointed out that the technical solutions and technical features provided in each part of the present application, including the following description, can be combined with each other without conflict.

[0027] In addition, the embodiments of the present application involved in the following description are generally only a part of the embodiments of the present application, not all. Therefore, based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should be within the scope of protection of the present application.

[0028] The present application will be described in detail below with reference to the drawings. Those skilled in the art will be able to implement the present application based on these descriptions. Before the present application is described in detail with reference to the drawings, it should be specifically pointed out that the technical solutions and technical features provided in each part of the present application, including the following description, can be combined with each other without conflict.

[0029] As shown in Figures 1-3, the present application provides an inertial bridge transverse dynamic deflection measuring device, which does not require visibility, liquid pipeline laying, and fixed reference points during use, and includes a shell 1, a spring 2, a mass 3, a first limiting mechanism, and a displacement meter 4.

[0030] The mass 3 is located in the shell 1, one end of a pair of springs 2 is symmetrically fixed to both ends of the mass 3, the other end of the spring 2 is fixed to the inner wall of the shell 1, one side end plate of the shell 1 connected with the spring 2 is provided with a circular through hole, and the test end of the displacement meter 4 measures the relative displacement amount of the mass 3 and the shell 1 through the through hole. Since the spring 2 is soft, in order to avoid the mass 3 from shaking greatly, a first limiting mechanism is provided, which is used to offset the total weight of the mass 3 and the magnet arranged thereon, and ensure that the mass 3 always moves along the bridge transversely in the middle of the shell 1.

[0031] The technical scheme can further include the following technical details to better achieve the technical effects: the mass block 3 is a hollow structure.

[0032] The technical scheme can further include the following technical details to better achieve the technical effects: the top plate of the shell 1 is made of a conductive material, which can be an aluminum plate or a copper plate, but is not limited to the two materials listed. The top plate of the shell 1 is made of a material with good conductive performance, and a certain eddy current damping is generated by the relative motion of the fifth magnet arranged on the upper surface of the mass block 3, thereby achieving high precision and environmental adaptability of the bridge transverse deflection measurement device.

[0033] The technical scheme can further include the following technical details to better achieve the technical effects: it further includes a power supply assembly 5 and a data transmission module 6 fixed to the surface of the shell 1; the power supply assembly 5 is electrically connected to the displacement meter 4 and continuously supplies power to the displacement meter 4, and the data transmission module 6 is electrically connected to the displacement meter 4 and saves and transmits the measurement data.

[0034] The technical scheme can further include the following technical details to better achieve the technical effects: the first limiting mechanism includes a first magnet 7 and a second magnet 8, the first magnet 7 is fixed to the bottom of the shell 1, the second magnet 8 is fixed to the bottom of the mass block 3, the first magnet 7 and the second magnet 8 have the same magnetic pole, and the repulsive magnetic force between the first magnet 7 and the second magnet 8 is the same as the total weight of the mass block 3 and the magnets arranged thereon.

[0035] The technical scheme can further include the following technical details to better achieve the technical effects: it further includes a second limiting mechanism including a third magnet 9 and a fourth magnet 10, the fourth magnet 10 is arranged on both sides of the mass block 3 without the spring 2, the fourth magnet 10 is fixed to the side surface of the inner wall of the shell 1 relative to the third magnet 9, and the third magnet 9 and the fourth magnet 10 have the same magnetic pole, thereby eliminating the lateral deviation of the mass block 3 during movement. Thus, the automatic high-precision measurement of the bridge transverse deflection without the need for a clear view, as well as the miniaturization and portability of the measurement device, are achieved.

[0036] The technical scheme can further include the following technical details to better achieve the technical effects: the first limiting mechanism includes a sliding device, the mass block 3 is placed on the sliding device, and the sliding device can move in a direction parallel to the axis of the spring 2. The sliding device includes a roller, a transverse limiting plate arranged transversely in the inner side of the roller, and a connecting structure connecting the mass block 3 to the roller.

[0037] The technical scheme can further include the following technical details to better achieve the technical effects: the first limiting mechanism is a liquid medium filled in the shell 1, and the through hole at the shell 1 needs to be sealed by the transparent sheet, but does not affect the measurement of the displacement meter 4, the liquid medium provides the same buoyancy as the total gravity of the mass block 3 and the magnet arranged thereon, and the existence of the liquid damping force can improve the transverse dynamic displacement measurement accuracy of the device and the environmental adaptability. When the first limiting mechanism includes both the liquid medium and the sliding device, the function of the liquid medium is mainly to provide damping, thereby improving the accuracy of the measurement device.

[0038] The technical scheme can further include the following technical details to better achieve the technical effects: the top of the mass block 3 is provided with a fifth magnet, the fifth magnet is combined with the metal shell 1 at the top, so that the damping size is adjusted according to the distance between the metal shell 1 at the top and the fifth magnet.

[0039] The application also provides a method for measuring the transverse dynamic deflection of a bridge by using the inertial bridge transverse dynamic deflection measuring device.

[0040] S1, fixing the measuring device on a bridge beam to be measured, so that the axis direction of the spring 2 is transversely parallel to the beam body;

[0041] S2, recording the transverse displacement of the mass block 3 measured by the displacement meter 4 as the transverse dynamic deflection of the bridge.

[0042] It should be noted that the measuring device of the application can also be used in the fields of monitoring / measuring the horizontal dynamic displacement of bridge towers, bridge piers and high-rise buildings.

[0043] Theoretical explanation of the accuracy of the inertial bridge transverse dynamic deflection measuring device:

[0044] A coordinate system as shown in FIG. 3 is established, y is the transverse displacement of the main beam (also the displacement of the device shell), x is the displacement of the mass block 3, and the transverse dynamic displacement y of the main beam is set as: y=Asinωt (1)

[0045] Wherein, A is the amplitude of the transverse dynamic displacement of the main beam, ω is the circular frequency of the transverse vibration of the main beam, and t is the time.

[0046] Then the motion differential equation of the mass block 3 is:

[0047] The measured value u of the displacement meter 4 in the bridge transverse dynamic deflection measuring device is the relative displacement amount of the mass block 3 and the shell 1, that is: u=x-y (3)

[0048] The relative motion differential equation of the mass block 3 can be obtained by bringing formula (3) into formula (2):

[0049] The solution of the steady vibration of formula (4) is:

[0050] wherein,

[0051] λ is the frequency ratio, (ω n is the inherent circular frequency of the measuring device); ζ is the damping ratio.

[0052] The displacement amplitude U of the mass 3 measured by the displacement meter 4 is taken as the output, when ω>>ω n , λ→∞, and there is:

[0053] Formula (8) shows that when the frequency ratio (the frequency of the structure to be measured / the frequency of the device itself) λ>2.5 and the damping ratio ζ is 0.6-0.7, the measured value of the lateral dynamic deflection of the structure to be measured is basically equal to the actual value, and the test precision is improved with the increase of the frequency ratio.

[0054] In practical engineering applications, with the continuous decrease of the span of the bridge, the frequency of the lateral dynamic deflection of the structure is continuously increased, and under the condition that the testing device is unchanged, the frequency ratio λ is continuously increased, and the test precision of the lateral dynamic deflection of the bridge will be further improved. That is, the lateral dynamic deflection amplitude of the large-span bridge is large, and the precision requirement of the testing device is low; the lateral dynamic deflection amplitude of the small-span bridge is small, and the precision requirement of the testing device is high; these requirements are completely consistent with the characteristics of the above device. The device has good self-adaptive characteristics in the process of testing the lateral dynamic deflection of the bridge, and well meets the actual needs of engineering.

[0055] Although the embodiments of the present application have been disclosed as above, it is not limited to the application listed in the specification and the embodiments, and it can be fully applied to various fields suitable for the present application, and other modifications can be easily realized by those skilled in the art, and therefore the present application is not limited to specific details and the examples shown and described herein, without departing from the general concept defined by the claims and the equivalent scope.

Claims

1. An inertial bridge transverse deflection measuring device, characterized in that, The application relates to a bridge transverse dynamic deflection measuring device, which comprises a shell, springs, a mass block, a first limiting mechanism and a displacement meter. The mass block is arranged in the shell, one end of a pair of springs is fixed to the two ends of the mass block, the other end of the springs is fixed to the inner wall of the shell, one side end plate of the shell connected with the springs is provided with a through hole, a test end of the displacement meter measures the relative displacement amount of the mass block and the shell through the through hole, and the first limiting mechanism is used for offsetting the total gravity of the mass block.

2. The inertial bridge transverse deflection measuring device of claim 1, wherein, The mass block is a hollow structure.

3. The inertial bridge transverse deflection measuring device of claim 1, wherein, The top plate of the shell is made of conductive material.

4. [Amended pursuant to Rule 26 17.03.2025] The inertial bridge transverse deflection measuring device as claimed in claim 1, characterized in that The device further comprises a power supply assembly and a data transmission module; the power supply assembly is electrically connected with the displacement meter and continuously supplies power for the displacement meter, and the data transmission module is electrically connected with the displacement meter and saves and transmits the measured data.

5. [Amended pursuant to Rule 26 17.03.2025] The inertial bridge transverse deflection measuring device as claimed in claim 1, characterized in that The first limiting mechanism comprises a first magnet and a second magnet, the first magnet is fixed to the bottom of the shell, the second magnet is fixed to the bottom of the mass block, the first magnet and the second magnet have the same magnetic pole, and the repulsion magnetic force between the first magnet and the second magnet is the same as the total gravity of the mass block and the magnet arranged on the mass block.

6. The inertial bridge transverse deflection measuring device of claim 5, wherein, The device further comprises a second limiting mechanism, which comprises a third magnet and a fourth magnet, the fourth magnet is arranged on the two sides of the mass block without springs, the fourth magnet is fixed to the side of the inner wall of the shell relative to the third magnet, and the third magnet and the fourth magnet have the same magnetic pole.

7. The inertial bridge transverse deflection measuring device of claim 3, wherein, The top of the mass block is provided with a fifth magnet.

8. A method of measuring lateral deflection of a bridge using the inertial bridge lateral deflection measuring device according to any one of claims 1 to 7, characterized by, The application further relates to a bridge transverse dynamic deflection measuring method. S1, fixing the measuring device on a bridge beam to be measured, so that the axis direction of the springs is transversely parallel to the beam; S2, recording the transverse displacement of the mass block measured by the displacement meter, which is the bridge transverse dynamic deflection.

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