High-precision measurement device for lateral dynamic displacement of cable-stayed bridge based on lever amplification

Abstract

This invention discloses a high-precision measuring device for the lateral dynamic displacement of a cable-stayed bridge based on lever amplification. It includes a displacement testing lever, a lateral limiting pin, and a video device, all perpendicular to the cable's axis. The upper end of the displacement testing lever is hinged to the cable, and a measurement mark is provided on its lower surface. The video device is fixedly mounted, with the measurement mark located within its field of view. The lateral limiting pin is fixed by a reference bracket fixed to the top surface of the main beam. The displacement testing lever has a hollow structure in its middle section along its length, and the lateral limiting pin passes precisely into this hollow structure, located in the upper-middle part of the lever. The lateral limiting pin is perpendicular to the axis of the displacement testing lever. This invention amplifies the lateral dynamic displacement of the cable-stayed bridge using a displacement testing lever, thus solving the problem of insufficient sensitivity of traditional sensors in measuring small lateral displacements of cable-stayed bridges. It offers advantages of economy, applicability, and high precision.

Description

Technical Field

[0001] This utility model relates to the field of measurement technology for long-span bridge equipment. More specifically, this utility model relates to a high-precision measuring device for the lateral dynamic displacement of stay cables based on lever amplification. Background Technology

[0002] As a long-span bridge structure, the stay cables of a cable-stayed bridge are key components that bear loads and transmit forces. Under external excitations such as wind loads and traffic loads, stay cables are prone to lateral vibrations, and their vibration displacement in the normal plane directly reflects the stress state and vibration characteristics. Currently, external dampers are not ideal in suppressing out-of-plane vibrations of stay cables, mainly because of inaccurate understanding of the direction, magnitude, and time-domain characteristics of the vibration displacement. Existing measurement methods are not sensitive enough to meet the high-precision measurement needs of small lateral displacements of stay cables. Therefore, accurately obtaining the displacement values ​​in the normal plane of stay cables, especially the lateral displacement values ​​and their variation patterns, is of significant theoretical guiding importance for improving the out-of-plane vibration control effect of external vibration control devices.

[0003] The existing technology for measuring and analyzing the transverse displacement of cable-stayed bridges still has the following shortcomings:

[0004] (1) Limitations of wire sensors: When directly measuring the transverse displacement of a stay cable bridge using wire sensors, a fixed location is required as a reference point, and it is difficult to find a suitable reference point near the stay cable. In addition, wire sensors are only suitable for measuring displacement in a single direction, which is not suitable for measuring multi-directional displacement of stay cables under environmental and traffic loads.

[0005] (2) Shortcomings of satellite systems: Measurement methods based on satellite systems (such as Beidou and GPS) are not accurate enough for measuring small-amplitude dynamic displacements, and the equipment costs are high, which is not conducive to large-scale promotion and use.

[0006] (3) Deficiencies of image processing technology: Extracting displacement information by taking images of cable vibration and combining them with edge line image processing algorithms requires a wide field of view and fixed video equipment, resulting in poor environmental adaptability. Furthermore, the image processing technology is complex and has low accuracy.

[0007] (4) Accelerometer error problem: When an accelerometer is installed on the cable-stayed bridge and the displacement is obtained by integration, the selection of boundary conditions can easily introduce large errors, affecting the accuracy of the measurement results.

[0008] The aforementioned shortcomings limit in-depth research on the vibration characteristics of stay cables and also restrict the effective suppression of lateral vibration of stay cables by existing damping devices. Therefore, this application proposes a high-precision monitoring device for the lateral dynamic displacement of stay cables based on lever amplification, so as to achieve economical, applicable and high-precision measurement of the lateral dynamic displacement of stay cables. The data obtained will be directly applied to the study of the vibration characteristics of stay cables and the design optimization of external vibration damping devices for stay cables, significantly improving the lateral (out-of-plane) vibration damping effect, effectively suppressing harmful vibrations and improving the durability of stay cables. Utility Model Content

[0009] One objective of this invention is to provide a high-precision measuring device for the lateral dynamic displacement of a cable-stayed bridge based on lever amplification. This device amplifies the lateral dynamic displacement of the cable-stayed bridge by using a displacement testing lever, thereby solving the problem of insufficient sensitivity of traditional sensors in measuring small lateral displacements of cable-stayed bridges. It has the advantages of being economical, applicable, and highly accurate.

[0010] To address the aforementioned technical problems, this utility model provides a high-precision measuring device for the lateral dynamic displacement of a stay cable based on lever amplification. The device includes a displacement testing lever, a lateral limiting pin, and a video device, all perpendicular to the cable's axis. The upper end of the displacement testing lever is hinged to the stay cable, and a measurement mark is provided on the lower surface of the lever. The video device is fixedly mounted, with the measurement mark located within its field of view. The lateral limiting pin is fixedly mounted via a reference bracket fixed to the top surface of the main beam. The displacement testing lever has a hollow structure in its middle section along its length, and the lateral limiting pin passes precisely into this hollow structure and is located in the upper-middle part of the displacement testing lever. The lateral limiting pin is perpendicular to the axis of the displacement testing lever.

[0011] Preferably, the stay cable is provided with a cable clamp, and the displacement testing lever is hinged to the cable clamp to enable the displacement testing lever to rotate in the transverse direction of the bridge.

[0012] Preferably, the cable clamp is provided with a pair of cable clamp lugs, which are rotatably connected to the upper end of the displacement testing lever via a rotating pin.

[0013] Preferably, the side of the reference bracket facing the displacement test lever is an inclined plane parallel to the displacement test lever, and its lower end is fixed by a pre-embedded plate on the top surface of the main beam.

[0014] Preferably, the inclined surface of the reference bracket is provided with multiple sets of threaded holes, and the lateral limiting pin is fixedly connected to the reference bracket through a connecting base. The connecting base is selectively disposed in any set of threaded holes to enable the lateral limiting pin to be disposed at different positions of the displacement test lever.

[0015] Preferably, the bottom end of the reference bracket is provided with a fixed bracket, which is L-shaped, and the video device is mounted on the fixed bracket so that the measurement mark point located on the outer surface of the bottom end of the displacement test lever is located in the middle of the field of view of the video device.

[0016] Preferably, the video device is an edge computing device and has built-in hardware and software for real-time processing of the measurement marker point image.

[0017] Preferably, the video device is connected to a wireless router via a network cable, and the wireless router transmits the image data processed by the video device to the cloud acquisition system.

[0018] Preferably, a solar panel is provided on the side of the reference bracket, and a matching battery for the solar panel is provided on the lower surface of the reference bracket, which is used to power the video equipment.

[0019] This utility model has at least the following beneficial effects:

[0020] 1. The measuring device of this application amplifies the lateral dynamic displacement of the cable-stayed bridge by means of a displacement testing lever, thereby solving the problem of insufficient sensitivity of traditional sensors in measuring small lateral displacements of cable-stayed bridges; the non-contact measurement method combined with the lever is intuitive and simple, and has the advantages of being economical, applicable and highly accurate.

[0021] 2. The lateral limiting pin in the measuring device of this application does not affect the change and measurement of the vertical (in-plane) displacement of the stay cable. Therefore, the specific mechanical structure of this application simplifies the measurement process and improves the sensitivity and accuracy of measuring the lateral dynamic displacement of the stay cable.

[0022] 3. The measuring device of this application realizes real-time high-precision measurement of the out-of-plane vibration displacement law of the cable-stayed bridge, which can be used to guide the design optimization of external dampers, so as to achieve effective control of the out-of-plane vibration of the cable-stayed bridge, comprehensively improve the environmental adaptability and vibration reduction / suppression effect of the external damper, and reduce the maintenance cost of the cable-stayed bridge.

[0023] Other advantages, objectives and features of this invention will be partly apparent from the following description, and partly understood by those skilled in the art through study and practice of this invention. Attached Figure Description

[0024] Figure 1 This is a front view of the overall structure of this utility model;

[0025] Figure 2 This is a side view comparison diagram of the overall structure of this utility model before and after displacement;

[0026] Figure 3 This is a simplified diagram illustrating the calculation principle of the lateral dynamic displacement when the stay cable of this utility model only undergoes lateral displacement;

[0027] Figure 4 This is a simplified diagram illustrating the calculation principle of lateral dynamic displacement when the stay cable of this utility model undergoes simultaneous lateral and vertical displacement.

[0028] Explanation of reference numerals in the attached figures:

[0029] 1. Stay cable, 2. Cable clamp, 3. Displacement test lever, 4. Lateral limit pin, 5. Reference bracket, 6. Measurement mark point, 7. Video equipment, 8. Fixed bracket, 9. Embedded plate, 10. Rotating pin, 11. Connecting base. Detailed Implementation

[0030] To better understand the purpose, structure, and function of this utility model, the following detailed description is provided in conjunction with the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0031] It should be noted that in the description of this utility model, the terms "horizontal", "longitudinal", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0032] like Figure 1 and Figure 2 As shown, this utility model provides a high-precision measuring device for the lateral dynamic displacement of a stay cable based on lever amplification. It includes a displacement testing lever 3, a lateral limiting pin 4, and a video device 7, which are arranged perpendicular to the axis of the stay cable 1. The upper end of the displacement testing lever is hinged to the stay cable, and a measurement mark point 6 is provided on the lower surface of the displacement testing lever. The video device is fixedly installed, and the measurement mark point is located in the field of view of the video device. The lateral limiting pin is fixedly installed by a reference bracket 5 fixed to the top surface of the main beam. The displacement testing lever has a hollow structure in the middle part along its length direction. The lateral limiting pin passes through the hollow structure and is located in the upper middle part of the displacement testing lever. The lateral limiting pin is arranged perpendicular to the axis of the displacement testing lever.

[0033] The cable stay is equipped with a cable clamp 2, and the displacement testing lever is hinged to the cable clamp to allow the displacement testing lever to rotate in the transverse direction of the bridge. The cable clamp is equipped with a pair of cable clamp lugs, which are rotatably connected to the upper end of the displacement testing lever via a rotating pin 10.

[0034] The high-precision measuring device for the lateral dynamic displacement of a cable-stayed bridge based on lever amplification provided in this application first installs a cable clamp on the cable. The displacement testing lever and the cable clamp are rotatably connected via a rotating pin. The middle part of the displacement testing lever has a hollow structure with a lateral limiting pin inserted inside. When the cable-stayed bridge experiences lateral displacement, the displacement testing lever rotates around the lateral limiting pin, and the lateral limiting pin does not restrict the linear movement of the displacement testing lever. The displacement testing lever is perpendicular to the cable clamp axis, and its bottom upper surface has measurement markers (target marks). A reference bracket is fixed to the bridge deck, and a video device is fixedly connected to the lower top surface of the reference bracket via a fixed bracket. The measurement markers (target marks) on the displacement testing lever are positioned in the center of the video device's field of view.

[0035] When the cable vibrates, the displacement testing lever moves accordingly. The video equipment directly records the movement trajectory of the measurement mark point, i.e., the target mark, at close range and in high definition. This movement trajectory directly reflects the vibration law of the cable under load, such as the direction, magnitude and change law of the vibration displacement. Furthermore, parameters such as the cable vibration displacement value can be easily obtained.

[0036] In another technical solution, the side of the reference bracket facing the displacement test lever is an inclined plane parallel to the displacement test lever, and its lower end is fixed by a pre-embedded plate 9 on the top surface of the main beam. Multiple sets of threaded holes are provided on the inclined plane of the reference bracket, and the lateral limiting pin is fixedly connected to the reference bracket via a connecting base 11. The connecting base is selectively positioned within any set of threaded holes to allow the lateral limiting pin to be positioned at different locations on the displacement test lever.

[0037] The lateral limiting pin is fixedly connected to the upper surface of the reference bracket via a connecting base. The position of the connecting base on the reference bracket can be adjusted arbitrarily, and the fixing method is bolt fixing, thereby achieving the optimal arrangement of the displacement test lever fulcrum as needed. For example, Figure 3 As shown, by setting the position of the lateral limit pin, the change in the measured data can be increased by a factor of (L1-t1) / L0 without changing the original measuring equipment. This means the lateral displacement value of the cable-stayed bridge is increased by a factor of (L1-t1) / L0 before measurement, greatly improving the sensitivity and accuracy in measuring small lateral displacements of the cable-stayed bridge. The value of L1 / L0 can be reasonably set according to different situations.

[0038] In another technical solution, a fixed bracket 8, which is L-shaped, is provided at the bottom of the reference bracket. The video device is mounted on the fixed bracket so that the measurement mark point located on the outer surface of the bottom end of the displacement test lever is positioned in the center of the video device's field of view. The measurement mark point can be made of high-contrast reflective stickers to ensure clear identification during video recording.

[0039] In another technical solution, the video device is an edge computing device with built-in hardware and software for real-time processing of the measured marker point images. The video device is connected to a wireless router via a network cable, and the wireless router transmits the processed image data from the video device to a cloud acquisition system.

[0040] The video equipment can be a commonly available high-definition industrial camera, which offers high image clarity. The frame rate can be set to 30-60 frames per second to meet measurement requirements. As an edge computing device, the video equipment has built-in hardware and software for real-time processing of target images. The images are transmitted via network cable to a wireless router, which then remotely uploads them to a cloud-based acquisition system for storage, analysis, and display.

[0041] In another technical solution, a solar panel is provided on the side of the reference bracket, and a matching battery for the solar panel is provided on the lower surface of the reference bracket, which is used to power the video equipment.

[0042] The video equipment can be powered by any method, including solar panels. When using solar power, the solar panels and their associated batteries are fixedly mounted on the side and bottom surface of the reference bracket, respectively. Monocrystalline silicon solar panels, which have high conversion efficiency, can be selected. Lead-acid batteries can be used, as they are low-cost and offer stable performance.

[0043] The measuring device of this application amplifies the lateral dynamic displacement of the cable-stayed bridge by using a displacement testing lever, thus solving the problem of insufficient sensitivity of traditional sensors in measuring small lateral displacements of cable-stayed bridges. The non-contact measurement method combined with the lever is intuitive and simple. The specific measurement principle is shown below.

[0044] like Figure 3 and Figure 4 As shown, the distance from the center A of the rotating pin to the center O of the lateral limiting pin is L0, the distance from the center O of the lateral limiting pin to the center of the measuring mark point D is L1, the lateral displacement of the cable is Δ0 (the value to be measured), the lateral displacement of the measuring mark point is t0 (the measured value), the vertical displacement of the measuring mark point is t1 (the measured value), and the length of the displacement measuring lever is L. The measured values ​​t0 and t1 can be extracted from the image captured by the video equipment.

[0045] When the stay cable only undergoes lateral dynamic displacement, the calculation principle is simplified as follows: Figure 3 As shown in the figure, OA = L0, OD = L1, AD = L, CD = t1, AB = Δ0, EC = t0. The lateral dynamic displacement of the stay cable is: The measured values ​​here are EC and CD, i.e. t0 and t1. OA = L0 and AD = L are the initial values. From this, we can obtain the amplified lateral dynamic displacement Δ0 of the cable stay.

[0046] When the stay cable undergoes both lateral and vertical displacement simultaneously, the calculation principle is simplified as follows: Figure 4 As shown in the figure, OA=L0, OD=L1, AD=L, CD=t1, the lateral dynamic displacement is Δ0, and EC=t0. We can obtain:

[0047] (1)

[0048] (2)

[0049] Combining equations (1) and (2), we can obtain:

[0050] (3)

[0051] According to geometric relationships, we can obtain:

[0052] (4)

[0053] Solving equation (4) yields: (5)

[0054] Substituting equation (5) into equation (3) yields

[0055]

[0056] because

[0057] The formula for calculating the lateral dynamic displacement of the stay cable can then be obtained as follows:

[0058] .

[0059] It is understood that this utility model has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of this utility model. Although the embodiments of this utility model have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for this utility model, and other modifications can be easily made by those skilled in the art. Therefore, without departing from the general concept defined by the claims and their equivalents, this utility model is not limited to the specific details and examples shown and described herein.

Claims

1. A high-precision measuring device for the lateral dynamic displacement of a stay cable based on lever amplification, characterized in that, The device includes a displacement testing lever, a lateral limiting pin, and a video device, all positioned perpendicular to the axis of the stay cable. The upper end of the displacement testing lever is hinged to the stay cable, and a measurement mark is provided on the lower surface of the displacement testing lever. The video device is fixedly installed with the measurement mark located within its field of view. The lateral limiting pin is fixedly installed by a reference bracket fixed to the top surface of the main beam. The displacement testing lever has a hollow structure in its middle section along its length, and the lateral limiting pin passes precisely into the hollow structure and is located in the upper-middle part of the displacement testing lever. The lateral limiting pin is positioned perpendicular to the axis of the displacement testing lever.

2. The high-precision measuring device for the lateral dynamic displacement of a cable-stayed bridge based on lever amplification as described in claim 1, characterized in that, The cable is equipped with a cable clamp, and the displacement testing lever is hinged to the cable clamp to allow the displacement testing lever to rotate in the transverse direction of the bridge.

3. The high-precision measuring device for the lateral dynamic displacement of a cable-stayed bridge based on lever amplification as described in claim 2, characterized in that, The cable clamp is provided with a pair of cable clamp lugs, which are rotatably connected to the upper end of the displacement test lever through a rotating pin.

4. The high-precision measuring device for lateral dynamic displacement of a cable-stayed bridge based on lever amplification as described in claim 1, characterized in that, The side of the reference bracket facing the displacement test lever is an inclined plane parallel to the displacement test lever, and its lower end is fixed by a pre-embedded plate on the top surface of the main beam.

5. The high-precision measuring device for the lateral dynamic displacement of a cable-stayed bridge based on lever amplification as described in claim 4, characterized in that, The inclined surface of the reference bracket is provided with multiple sets of threaded holes, and the lateral limiting pin is fixedly connected to the reference bracket through a connecting base. The connecting base is selectively disposed in any set of threaded holes to enable the lateral limiting pin to be disposed at different positions on the displacement test lever.

6. The high-precision measuring device for lateral dynamic displacement of a cable-stayed bridge based on lever amplification as described in claim 4, characterized in that, The reference support is provided with a fixed bracket at the bottom, which is L-shaped. The video device is mounted on the fixed bracket so that the measurement mark point located on the outer surface of the bottom end of the displacement test lever is located in the middle of the video device's field of view.

7. The high-precision measuring device for lateral dynamic displacement of a cable-stayed bridge based on lever amplification as described in claim 1, characterized in that, The video device is an edge computing device, and it has built-in hardware and software for real-time processing of the measured marker point images.

8. The high-precision measuring device for lateral dynamic displacement of a cable-stayed bridge based on lever amplification as described in claim 7, characterized in that, The video device is connected to a wireless router via a network cable, and the wireless router transmits the image data processed by the video device to the cloud acquisition system.

9. The high-precision measuring device for lateral dynamic displacement of a cable-stayed bridge based on lever amplification as described in claim 4, characterized in that, A solar panel is provided on the side of the reference bracket, and a matching battery for the solar panel is provided on the lower surface of the reference bracket, which is used to power the video equipment.

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