Bridge displacement measuring system and method

Abstract

The invention discloses a bridge displacement measuring system and method. The system comprises a base, a vertical displacement measuring device and two horizontal displacement measuring devices which are arranged orthogonally. The vertical displacement measuring device directly measures the vertical displacement of the bridge through a sliding insertion rod with scales. Each horizontal displacement measuring device comprises a spherical hinge assembly and a connecting assembly, a sliding connector at the top end of the connecting assembly is clamped into a guide groove in the specific direction of the bottom face of the bridge, so that the combined displacement of the bridge is decoupled, each spherical hinge only responds to the horizontal displacement in the single direction, and the displacement angle is directly indicated through angle scales on the spherical face of the spherical hinge. According to the method, by means of the system, the vertical displacement of the bridge and the horizontal displacement information in the two orthogonal directions are synchronously obtained by reading the changes of the scales of the insertion rod and the spherical hinge angle. Synchronous and visual measurement of three-dimensional displacement of the bridge is achieved through a pure mechanical structure, external energy is not needed, and the device is firm, reliable, low in cost and suitable for long-term monitoring.

Description

Technical Field

[0001] This invention relates to the field of bridge technology, and more specifically to a bridge displacement measurement system and method. Background Technology

[0002] During operation, bridges experience vertical displacements (such as deflection and settlement) and horizontal displacements (such as expansion and contraction and lateral offset) due to factors such as load, environment, and material aging. Long-term and stable monitoring of these displacements is a key means of assessing the health and safety status of bridge structures.

[0003] Currently, bridge displacement measurement mainly relies on two types of technologies: First, electronic measurement systems based on total stations, GPS, or laser ranging. These systems offer advantages such as high accuracy and remote monitoring, but suffer from drawbacks including high equipment costs, dependence on a stable power supply, susceptibility to severe weather (such as dense fog or strong light), and high long-term operation and maintenance costs, making them difficult to widely adopt on a large number of bridges, especially those in remote areas. Second, simple mechanical measuring devices, such as dial indicators, micrometers, or simple scales. While these methods are lower in cost, they typically have limited functionality (often measuring only unidirectional displacement), and the readings are not intuitive, making it difficult to automatically record historical data. Especially for slow, minute creep displacements, changes in scale are difficult to detect with the naked eye.

[0004] Furthermore, a significant technical challenge lies in the decoupled measurement of displacement. The actual displacement of a bridge is three-dimensional, with vertical and horizontal displacements often occurring simultaneously and interrelated. Traditional, simple mechanical devices, when measuring vertical displacement, experience lateral friction from the bridge's horizontal movement, leading to sticking or distorted readings. Conversely, when measuring horizontal displacement, it is difficult to easily decompose the complex directional displacement into two orthogonal directions for independent and accurate measurement. Therefore, there is an urgent need for a mechanical measurement scheme that is relatively simple in structure, cost-effective, requires no external energy, and can synchronously and decoupledly achieve long-term reliable monitoring of the bridge's three-dimensional displacement. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the technical problem to be solved by the present invention is to provide a bridge displacement measurement system and method, which is a mechanical measurement scheme that is simple in structure, controllable in cost, requires no external energy, and can realize long-term reliable monitoring of bridge three-dimensional displacement synchronously.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a bridge displacement measurement system, comprising: Base; A vertical displacement measuring device includes a height measuring rod mounted on the base. The height measuring rod has a sleeve rod and a plug rod that slide together, and an elastic element that supports them. The bottom end of the sleeve rod is fixed to the base, and the top of the plug rod is used to abut against the bottom surface of the bridge. The plug rod has a scale on its side wall. A first horizontal displacement measuring device includes a first ball joint assembly and a first connecting assembly. The first ball joint assembly has a first ball joint seat fixed to a base and a first ball joint rotatably housed therein. The spherical surface of the first ball joint is provided with a first angle scale. The first connecting assembly includes a first telescopic rod fixedly connected to the first ball joint and a first sliding joint hinged to the top end of the first telescopic rod. The first sliding joint is used to slidably engage with a first guide groove extending along a second direction on the bottom surface of the bridge. The second horizontal displacement measuring device includes a second ball joint assembly and a second connecting assembly, which are structurally identical to and orthogonally arranged with the first horizontal displacement measuring device, and are used to measure the displacement of the bridge in a second direction perpendicular to the first direction. The second sliding joint is used to slidably engage with a second guide groove extending along the first direction on the bottom surface of the bridge.

[0007] Furthermore, the top of the insertion rod is provided with a freely rolling ball, and the insertion rod abuts against the bottom surface of the bridge through the ball.

[0008] Furthermore, it also includes a linear displacement amplification mechanism, which is disposed between the base and the insertion rod, and is used to amplify and record the linear displacement of the insertion rod.

[0009] Furthermore, the linear displacement amplification mechanism includes a rack, a sector gear, a first swing arm, a first pen, and a first recording plate; the rack is vertically fixed to the outer wall of the insert rod; the sector gear is rotatably mounted on the base via a rotating shaft and meshes with the rack; the first swing arm is fixed to the sector gear and extends radially outward; the first pen is disposed at the end of the first swing arm; the first recording plate is fixed to the base, and the tip of the first pen slides in contact with the recording surface of the first recording plate.

[0010] Furthermore, at least one tooth of the sector gear is formed as a first ratchet structure capable of transmitting motion in one direction. The first ratchet structure includes a first actuating rod hinged to the sector gear body and a first stop fixed to the sector gear body and used to support the first actuating rod. The first actuating rod can mesh with the rack to drive the sector gear to rotate in one direction.

[0011] Furthermore, it also includes a first angle magnification and recording mechanism for magnifying and recording the rotation angle of the first ball joint; and / or, the second horizontal displacement measuring device further includes a second angle magnification and recording mechanism for magnifying and recording the rotation angle of the second ball joint.

[0012] Further, the first angle magnification recording mechanism and / or the second angle magnification recording mechanism include a driving gear, a driven gear, a driven shaft, a second swing arm, a slider, a connecting rod, a third swing arm, a second pen, and a second recording plate; the driving gear is fixed to a corresponding ball joint and rotates with it; the driven shaft is rotatably and laterally disposed on the base; the driven gear is fixed to one end of the driven shaft and meshes with the driving gear; one end of the second swing arm is fixed to the driven shaft; the slider is slidably sleeved on the second swing arm; one end of the connecting rod is hinged to the base, and the other end is hinged to the slider; the middle part of the third swing arm is rotatably connected to the base through a fixed shaft, and a groove is formed on the third swing arm along its length direction; the other end of the second swing arm is provided with a pin, which is slidably inserted into the groove; the second pen is disposed at the free end of the third swing arm; the second recording plate is fixed to the base, and the tip of the second pen contacts the recording surface of the second recording plate.

[0013] Furthermore, at least one tooth of the driven gear is formed as a second ratchet structure capable of transmitting motion in one direction. The second ratchet structure includes a second actuating rod hinged to the driven shaft and a second stop fixed to the driven shaft and used to support the second actuating rod. The second actuating rod can mesh with the driving gear to drive the driven shaft to rotate in one direction.

[0014] Furthermore, the first sliding joint and the second sliding joint are pulley assemblies or slider assemblies.

[0015] A bridge displacement measurement method, using the aforementioned bridge displacement measurement system to measure bridge displacement, includes the following steps: The base is fixed at a preset position under the bridge, so that the top of the plug abuts against the bottom surface of the bridge, and the first sliding joint and the second sliding joint are respectively inserted into the corresponding first guide groove and the second guide groove. The vertical displacement of the bridge is obtained based on the change in the scale on the insertion rod; Based on the change of the first angle scale on the first ball joint, the displacement angle information of the bridge in the first horizontal direction is obtained; Based on the change in the second angle scale on the second ball joint, the displacement angle information of the bridge in the second horizontal direction is obtained.

[0016] The beneficial effects of this invention are: The aforementioned bridge displacement measurement system has at least the following advantages: 1. The system integrates a vertical displacement measuring device and two orthogonally arranged horizontal displacement measuring devices. The vertical device directly measures vertical displacement via a graduated sliding rod, while the two horizontal devices are dedicated to measuring horizontal displacement in two mutually perpendicular directions (e.g., longitudinal and transverse directions). Crucially, each horizontal measuring device, through its sliding joint and corresponding directional guide groove, constrains and decomposes the bridge's total displacement. For example, the device measuring X-direction displacement has its sliding joint restricted to sliding within the Y-direction guide groove, ensuring that the device is only sensitive to X-direction displacement. The rotation angle of its ball joint directly reflects the X-direction displacement component, while the Y-direction displacement is absorbed by the sliding of the guide groove, preventing interference with the device's readings. The two orthogonally arranged devices work together to acquire complete and independent three-dimensional displacement data, fundamentally solving the problems of measurement interference and coupling.

[0017] 2. All measurements are based on mechanical structure and visual readings. Vertical displacement is obtained directly by observing changes in the scale on the insertion rod; horizontal displacement is obtained by observing changes in the angle scale fixed to the ball joint. This purely mechanical measurement method is completely independent of electricity and complex electronic components, is resistant to electromagnetic interference, and can withstand high and low temperatures and humid environments, making it particularly suitable for long-term deployment on bridges in the field. The read scale values ​​are absolute displacements relative to the fixed base, providing a clear concept and eliminating the need for complex coordinate system transformations or reference point maintenance.

[0018] 3. Compared to expensive automated electronic monitoring systems, this system significantly reduces manufacturing and maintenance costs, making it possible to deploy health monitoring on a large scale on more bridges, especially small and medium-sized bridges, old bridges, and bridges in remote areas. Attached Figure Description

[0019] To more clearly illustrate the specific embodiments of the present invention, the accompanying drawings used in the specific embodiments will be briefly described below. In all the drawings, the elements or parts are not necessarily drawn to scale.

[0020] Figure 1 This is a schematic diagram of a bridge displacement measurement system provided in an embodiment of the present invention; Figure 2 for Figure 1 A partial schematic diagram of point A in the middle; Figure 3 for Figure 1 A schematic diagram of the bridge displacement measurement system from another angle; Figure 4 for Figure 3 A partial schematic diagram at point B in the middle; Figure 5 for Figure 3 A partial schematic diagram at point C in the middle; Figure label: 1. Bridge; 100. Base; 200. Vertical displacement measuring device; 210. Height measuring rod; 220. Ball bearing; 300. First horizontal displacement measuring device; 310. First ball joint assembly; 311. First ball joint connector; 312. First ball joint; 320. First connecting assembly; 321. First telescopic rod; 322. First sliding joint; 400. Linear displacement amplification mechanism; 410. Rack; 420. Sector gear; 421. First actuating rod; 422. First stop; 430. First swing arm; 440. Pen; 450. First recording plate; 500. First angle amplification and recording mechanism; 510. Driving gear; 520. Driven gear; 530. Driven shaft; 540. Second swing arm; 550. Slider; 560. Connecting rod; 570. Third swing arm; 580. Pen; 590. Recording plate; 600. Second horizontal displacement measuring device. Detailed Implementation

[0021] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the invention; therefore, the invention is not limited to the specific embodiments disclosed below.

[0022] Please see Figures 1 to 5 The present invention provides a bridge displacement measurement system, which aims to achieve synchronous and independent measurement of the vertical displacement of the bridge and the displacement in two orthogonal horizontal directions.

[0023] The system includes a base 100. This base 100 is typically constructed from welded / bolted metal sheets or profiles, possessing sufficient rigidity and mass. Its bottom surface is secured to a stable foundation beneath the bridge 1, such as a pier, cap beam, or dedicated observation pier, using anchor bolts or high-strength chemical anchors. The stability of the base 100 ensures that the reference zero point of the entire measurement system remains fixed.

[0024] A vertical displacement measuring device 200 is provided on the base 100. It includes a height measuring rod 210 provided on the base 100. The height measuring rod 210 has a sleeve rod and a plug rod that slide against each other, and an elastic element supporting them. The elastic element plug rod provides a continuous upward elastic preload. The bottom end of the sleeve rod is fixed to the base 100, and the top of the plug rod is used to abut against the bottom surface of the bridge 1. Its side wall is engraved with a scale in millimeters along the axial direction.

[0025] During installation, the height of the base 100 is adjusted or the extension and retraction of the insert rod are used to ensure that the insert rod is in close contact with the bridge bottom under the preload of the spring. When the bridge 1 undergoes vertical displacement (such as sinking or arching), the bridge bottom will press the insert rod to slide relative to the sleeve rod, or allow it to extend under the action of the spring. At this time, the change in position of the scale line on the insert rod relative to the upper edge of the sleeve rod (or a fixed pointer) is recorded.

[0026] To measure horizontal displacement, the system has two independent and orthogonally arranged measuring devices. The first horizontal displacement measuring device 300 is used to measure the displacement of bridge 1 along a first direction (e.g., the longitudinal direction, defined as the X direction). It includes a first ball joint 312 assembly 310 and a first connecting assembly 320. The first ball joint 312 assembly 310 consists of a first ball joint connector 311 fixed on the base 100 and a matching first ball joint 312, which can rotate freely within the spherical groove of the connector. On the spherical surface of the first ball joint 312, a first angle scale is engraved along a specific great circle (i.e., the "first measuring plane," typically a plane containing the initial axis of the device and perpendicular to the X direction). The first connecting assembly 320 includes a first telescopic rod 321 (such as a sleeve-type telescopic rod) and a first sliding joint 322. The bottom end of the first telescopic rod 321 is rigidly connected to the first ball joint 312, and the top end is connected to the first sliding joint 322 via a hinge (such as a universal joint). The first sliding joint 322 is designed to slidably snap into a first guide groove that is pre-installed on the bottom surface of the bridge 1 and extends strictly along the second direction (i.e., the Y direction, transverse direction of the bridge).

[0027] The second horizontal displacement measuring device 600 is used to measure the displacement of bridge 1 along the Y direction. Its structure is exactly the same as the first device, but it is arranged orthogonally in space. Its second sliding joint is inserted into the second guide groove extending along the X direction on the bottom surface of bridge 1. The plane containing the second angle scale line on the second ball joint (the second measuring plane) is perpendicular to the first measuring plane.

[0028] Taking the first device as an example, its guide groove restricts the sliding joint to slide freely only in the Y direction. When bridge 1 only displaces in the X direction, the constraint of the second guide groove (belonging to another device) allows bridge 1 to drive the first sliding joint 322 to move in the X direction. However, since the length of the first telescopic rod 321 can be adapted through the rotation of the ball joint and its own extension and retraction, this movement in the X direction is mainly converted into the oscillation of the first telescopic rod 321 around the center of the first ball joint 312, forcing the first ball joint 312 to rotate in its spherical groove around an axis perpendicular to the X direction. At this time, the projection of the axis of the first telescopic rod 321 onto the surface of the first ball joint 312 will move. By reading its change value relative to the first angle scale, the displacement angle of bridge 1 in the X direction can be obtained. Combined with the instantaneous length L of the first telescopic rod 321, the actual horizontal displacement component can be calculated. Similarly, the second device independently measures the displacement in the Y direction. If bridge 1 experiences a resultant displacement in any direction, it can be decomposed and measured synchronously and independently by the two sets of devices. Its beneficial effect is that, through the ingenious constraint of "spherical joint + guide groove", the complex spatial displacement is decomposed and transformed into two simple single-axis rotations of the spherical joint for measurement. The structure is clear, the decoupling is good, and the mutual interference between measurements is avoided.

[0029] This embodiment is an optimization based on Embodiment 1. One or more freely rolling balls 220 are embedded at the top of the insertion rod of the vertical displacement measuring device 200. The balls 220 protrude, allowing the insertion rod to make point contact with the bottom surface of the bridge 1 through the spherical surface of the balls 220.

[0030] When bridge 1 undergoes horizontal displacement, it generates a lateral force on the vertical measuring device. Traditional fixed-end-face contact generates static friction, which may cause the probe to "get stuck" or introduce measurement errors. By using ball bearings 220, sliding friction is converted into rolling friction, significantly reducing frictional resistance. This makes the probe more sensitive to vertical displacement and able to more accurately reflect minute vertical changes. Simultaneously, when bridge 1 moves laterally, the ball bearings 220 can roll freely, allowing the contact point to move smoothly, further ensuring the independence of the vertical displacement readings.

[0031] This embodiment adds new features based on embodiment one or two, corresponding to claim 3. The system adds a linear displacement amplification mechanism 400, which is disposed between the base 100 and the insertion rod.

[0032] The long-term settlement or creep displacement of Bridge 1 is often minute and slow, making direct observation of scale changes insufficiently intuitive and difficult to record historical processes. This institution uses the principle of magnification to amplify the minute linear displacement of the insertion rod by tens or even hundreds of times, and converts it into a visual graphic trajectory recorded on a medium.

[0033] Specifically, the linear displacement amplification mechanism 400 includes a rack 410, a sector gear 420, a first pendulum 430, a first pen 440, and a first recording plate 450. The rack 410 is vertically fixed to the side of the insert rod. The sector gear 420 is mounted on a bearing in the base 100 via a horizontal pivot and meshes with the rack 410. The first pendulum 430 is fixed to the sector gear 420, serving as an extended pointer. The first pendulum 440 is mounted at the end of the first pendulum 430. The first recording plate 450 (such as a plate with graph paper attached) is fixed to the base 100, and the tip of the first pen 440 lightly touches the plate surface.

[0034] When the bridge 1 sinks, causing the insert rod and rack 410 to move downwards, the rack 410 drives the sector gear 420 to rotate. Let the displacement of the rack 410 be S, and the pitch circle radius of the sector gear 420 be r, then its rotation angle is θ = S / r. The length of the first pendulum 430 is R, and the linear displacement of its end, the first pendulum 440, is L = R * θ = (R / r) * S. Therefore, the magnification factor K = R / r. By designing R to be much larger than r (for example, R = 500 mm, r = 5 mm, then K = 100), a 1 mm actual displacement can be magnified to a 100 mm movement of the first pendulum 440, making the trajectory drawn by the first pendulum 440 on the first recording plate 450 clearly visible.

[0035] To ensure the mechanism focuses on recording cumulative settlement (preventing recording regression due to short-term elastic recovery or vibration of bridge 1), the teeth of the sector gear 420 are specially designed to form a first ratchet structure. This structure consists of a first actuating lever 421 and a first stop block 422. The first actuating lever 421 is hinged to the gear body and can swing slightly around the hinge axis; the first stop block 422 is fixed to the gear body and located below the actuating lever.

[0036] When bridge 1 sinks and rack 410 moves downward, the tooth surface of rack 410 pushes the working surface of the first actuating lever 421. Due to the support of the first stop block 422, the force is directly transmitted to the gear body, driving the sector gear 420 to rotate forward for recording. When bridge 1 rises and rack 410 moves upward, the back of rack 410 will contact and press down on the non-working surface of the first actuating lever 421, causing it to swing around the hinge axis and disengage, thus sliding over the gear without causing the sector gear 420 to reverse. This achieves unidirectional cumulative recording of displacement, and the recorded curve can clearly reflect the long-term trend dominated by settlement, filtering out short-term fluctuation interference and making data analysis simpler.

[0037] As a preferred embodiment, based on Embodiment 1, the first horizontal displacement measuring device 300 may be additionally equipped with a first angle magnification and recording mechanism 500; and the second horizontal displacement measuring device 600 may be additionally equipped with a second angle magnification and recording mechanism. The two mechanisms can be configured individually or simultaneously.

[0038] Because the angle scale changes on a ball joint often are very small, direct readings have limited accuracy. An angle magnification and recording mechanism amplifies the minute rotation of the ball joint and converts it into a large-amplitude 580° movement of the second pen for recording. This significantly improves the measurement resolution and visualization of the horizontal displacement angle, making it particularly suitable for monitoring minute horizontal deflections, torsional deformations, etc.

[0039] Specifically, the angle magnification recording mechanism includes a drive gear 510, a driven gear 520, a driven shaft 530, a second swing arm 540, a slider 550, a connecting rod 560, a third swing arm 570, a second pen 580, and a second recording plate 590. The driving gear 510 is fixed to the corresponding ball joint and rotates with it; the driven shaft 530 is rotatably and laterally arranged on the base 100; the driven gear 520 is fixed to one end of the driven shaft 530 and meshes with the driving gear 510; one end of the second rocker arm 540 is fixed to the driven shaft 530; the slider 550 is slidably sleeved on the second rocker arm 540; one end of the connecting rod 560 is hinged to the base 100, and the other end is hinged to the slider 550; the middle part of the third rocker arm 570 is rotatably connected to the base 100 through a fixed shaft, and a groove is provided on the third rocker arm 570 along its length; the other end of the second rocker arm 540 is provided with a pin, which is slidably inserted into the groove; the second pen 580 is disposed at the free end of the third rocker arm 570; the second recording plate 590 is fixed to the base 100, and the tip of the second pen 580 contacts the recording surface of the second recording plate 590.

[0040] During measurement, the rotation of the driven shaft 530 drives the second pendulum 540 to rotate as a crank. Constrained by the connecting rod 560, the slider 550 slides on the second pendulum 540, complicating the motion trajectory of the pin end. This trajectory drives the third pendulum 570 via a groove. Since the lever arm of the third pendulum 570 (from the fixed shaft to the tip of the second pen 580) is much larger than the resistance arm (from the fixed shaft to the force point of the groove), a secondary lever amplification is achieved. Ultimately, a rotation of a fraction of a degree in the ball joint can be amplified into a movement of several centimeters on the second recording plate 590 by the second pen 580. Through amplification, the invisible minute angular displacement is transformed into a clearly visible graphic.

[0041] As another preferred embodiment, a second ratchet structure is provided on the driven gear 520. The second ratchet structure includes a second actuating rod hinged to the driven shaft 530 and a second stop fixed to the driven shaft 530 for supporting the second actuating rod. The second actuating rod can mesh with the driving gear 510 to drive the driven shaft 530 to rotate in one direction.

[0042] Its working principle is similar to that of the first ratchet structure, realizing unidirectional transmission of motion. When the bridge 1 moves in a certain direction, driving the ball joint and the driving gear 510 to push the second actuating lever, power is transmitted and the mechanism records. When the bridge 1 has a reverse tendency, the reverse force of the driving gear 510 will cause the second actuating lever to disengage, the driven shaft 530 will not reverse, and thus the second pen 580 will not retract. This method ensures the unidirectionality and cumulativeity of horizontal displacement recording, enabling the recorded curve to stably reflect the net displacement trend of the bridge 1 in each horizontal direction, avoiding back-and-forth erasure of the recorded trajectory due to vibration and other reasons, and ensuring the clarity and usability of the data.

[0043] In practical implementation, the first sliding joint 322 and the second sliding joint can take the form of a pulley assembly or a slider 550 assembly.

[0044] In addition, the present invention also provides a method for measuring the displacement of a bridge 1, comprising the following steps.

[0045] Installation steps: Select the key monitoring section of bridge 1, install base 100 on the stable foundation below and level it. Install the first guide groove (along the transverse Y direction) and the second guide groove (along the longitudinal X direction) at predetermined positions on the bottom surface of bridge 1. Adjust the system so that the insertion rod is tightly abutted against the bridge bottom under spring preload (or through contact with ball bearings 220). Insert the first sliding joint 322 into the first guide groove and the second sliding joint into the second guide groove, and adjust the lengths of the two sets of telescopic rods to bring the entire system to the predetermined initial tension state. Record the initial scale and angle readings.

[0046] Vertical displacement measurement steps: During periodic inspections, directly read the change value ΔH of the scale on the insertion rod relative to the reference. This is the cumulative vertical displacement of bridge 1 since installation. If the system includes a linear displacement amplification mechanism 400, observe the trajectory on the first recording plate 450. This amplified curve can directly reflect the displacement change over time, and the actual displacement can be calculated using calibration coefficients.

[0047] First horizontal displacement measurement steps: Observe the first angle scale on the first ball joint 312 and read the angle change indicated by the axis of the first telescopic rod 321. Calculate the X-direction displacement component according to the corresponding company. If a first angle magnification recording mechanism 500 is included, read the magnified trajectory from the corresponding second recording plate 590 for analysis to obtain more accurate historical angle change data.

[0048] The second horizontal displacement measurement step is performed synchronously. Observe the second angle scale on the second ball joint, read the angle change, and calculate the Y-direction displacement component ΔY. If a second angle magnification recording mechanism is included, analyze the trajectory of its second recording plate 590.

[0049] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A bridge displacement measurement system, characterized in that, include: Base; A vertical displacement measuring device includes a height measuring rod mounted on the base. The height measuring rod has a sleeve rod and a plug rod that slide together, and an elastic element that supports them. The bottom end of the sleeve rod is fixed to the base, and the top of the plug rod is used to abut against the bottom surface of the bridge. The plug rod has a scale on its side wall. A first horizontal displacement measuring device includes a first ball joint assembly and a first connecting assembly. The first ball joint assembly has a first ball joint seat fixed to a base and a first ball joint rotatably housed therein. The spherical surface of the first ball joint is provided with a first angle scale. The first connecting assembly includes a first telescopic rod fixedly connected to the first ball joint and a first sliding joint hinged to the top end of the first telescopic rod. The first sliding joint is used to slidably engage with a first guide groove extending along a second direction on the bottom surface of the bridge. The second horizontal displacement measuring device includes a second ball joint assembly and a second connecting assembly, which are structurally identical to and orthogonally arranged with the first horizontal displacement measuring device, and are used to measure the displacement of the bridge in a second direction perpendicular to the first direction. The second sliding joint is used to slidably engage with a second guide groove extending along the first direction on the bottom surface of the bridge.

2. The bridge displacement measurement system according to claim 1, characterized in that, The top of the insertion rod is provided with a freely rolling ball, and the insertion rod abuts against the bottom surface of the bridge through the ball.

3. The bridge displacement measurement system according to claim 1, characterized in that, It also includes a linear displacement amplification mechanism, which is disposed between the base and the insertion rod, and is used to amplify and record the linear displacement of the insertion rod.

4. The bridge displacement measurement system according to claim 3, characterized in that, The linear displacement amplification mechanism includes a rack, a sector gear, a first pendulum, a first pen, and a first recording plate; the rack is vertically fixed to the outer wall of the insert rod; the sector gear is rotatably mounted on the base via a rotating shaft and meshes with the rack; the first pendulum is fixed to the sector gear and extends radially outward; the first pen is disposed at the end of the first pendulum; the first recording plate is fixed to the base, and the tip of the first pen slides in contact with the recording surface of the first recording plate.

5. The bridge displacement measurement system according to claim 4, characterized in that, At least one tooth of the sector gear is formed as a first ratchet structure capable of transmitting motion in one direction. The first ratchet structure includes a first actuating rod hinged to the sector gear body and a first stop fixed to the sector gear body for supporting the first actuating rod. The first actuating rod can mesh with the rack to drive the sector gear to rotate in one direction.

6. The bridge displacement measurement system according to claim 1, characterized in that, It also includes a first angle magnification and recording mechanism for magnifying and recording the rotation angle of the first ball joint; and / or, the second horizontal displacement measuring device further includes a second angle magnification and recording mechanism for magnifying and recording the rotation angle of the second ball joint.

7. The bridge displacement measurement system according to claim 6, characterized in that, The first angle magnification recording mechanism and / or the second angle magnification recording mechanism include a driving gear, a driven gear, a driven shaft, a second rocker arm, a slider, a connecting rod, a third rocker arm, a second pen, and a second recording plate; the driving gear is fixed to a corresponding ball joint and rotates with it; the driven shaft is rotatably arranged laterally on the base; the driven gear is fixed to one end of the driven shaft and meshes with the driving gear; one end of the second rocker arm is fixed to the driven shaft; The slider is slidably mounted on the second swing arm; one end of the connecting rod is hinged to the base, and the other end is hinged to the slider; the middle part of the third swing arm is rotatably connected to the base through a fixed shaft, and a groove is formed on the third swing arm along its length; the other end of the second swing arm is provided with a pin, which is slidably inserted into the groove; the second pen is disposed at the free end of the third swing arm; the second recording plate is fixed to the base, and the tip of the second pen contacts the recording surface of the second recording plate.

8. The bridge displacement measurement system according to claim 7, characterized in that, At least one tooth of the driven gear is formed as a second ratchet structure capable of transmitting motion in one direction. The second ratchet structure includes a second actuating rod hinged to the driven shaft and a second stop fixed to the driven shaft for supporting the second actuating rod. The second actuating rod can mesh with the driving gear to drive the driven shaft to rotate in one direction.

9. The bridge displacement measurement system according to any one of claims 1 to 8, characterized in that, The first sliding joint and the second sliding joint are pulley assemblies or slider assemblies.

10. A method for measuring bridge displacement, characterized in that, The bridge displacement measurement system according to any one of claims 1 to 9 includes the following steps: The base is fixed at a preset position under the bridge, so that the top of the plug abuts against the bottom surface of the bridge, and the first sliding joint and the second sliding joint are respectively inserted into the corresponding first guide groove and the second guide groove. The vertical displacement of the bridge is obtained based on the change in the scale on the insertion rod; Based on the change of the first angle scale on the first ball joint, the displacement angle information of the bridge in the first horizontal direction is obtained; Based on the change in the second angle scale on the second ball joint, the displacement angle information of the bridge in the second horizontal direction is obtained.

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