Suspension bridge cable clamp fastening state monitoring and slippage early warning method based on computer vision

Abstract

The invention discloses a suspension bridge cable clamp fastening state monitoring and slippage early warning method based on computer vision, and relates to the field of structure monitoring and nondestructive monitoring. The invention aims to solve the problem that long-term monitoring and slippage early warning of the fastening state of a cable clamp are difficult to realize due to lack of reliable means for long-term monitoring of the fastening state of the cable clamp at the present stage. According to the method, the tooth seam spacing, the radial pressure variation and the anti-sliding friction loss of the suspension bridge cable clamp are calculated respectively, so that the fastening state of the suspension bridge cable clamp is monitored. And taking the tooth seam spacing variation corresponding to the condition that the anti-sliding friction loss rate reaches 15% as a cable clamp slippage yellow early warning value, taking the tooth seam spacing variation corresponding to the condition that the anti-sliding friction loss rate reaches 30% as a cable clamp slippage red early warning value, monitoring the fastening state of the suspension bridge cable clamp in real time, and judging whether the suspension bridge cable clamp is in a slippage state or not.

Description

Technical Field

[0001] The invention belongs to the field of structural monitoring and non-destructive monitoring. Background Art

[0002] The cable clamp of a suspension bridge is a key component that connects the suspender cable and the main cable and ensures reliable transmission of force flow. It needs to have sufficient reliability, and its tightening state is one of the key factors affecting the safety of the suspension bridge structure. The cable clamp is generally composed of two semicircular steel components, which are tightened on the main cable by the pre-tightening force of the screw to form a cable clamp-main cable anchoring system. The cable clamp and the main cable resist the sliding force generated by the external load through the anti-sliding friction resistance generated by the radial pressure on the interface between the cable clamp and the main cable; among them, the anti-sliding friction resistance is closely related to the tightening state of the cable clamp.

[0003] As the service time of the cable clamp increases, under the influence of factors such as screw creep, cable force and temperature, the screw preload is gradually lost, resulting in a decrease in the tightening state of the cable clamp and a decrease in the anti-slip friction resistance of the cable clamp, which eventually causes the cable clamp to slip, endangering the safety of the suspension bridge structure.

[0004] At present, screw axial force monitoring is the main means of evaluating the tightening state of cable clamps. There are usually two methods for screw axial force monitoring: direct monitoring and indirect monitoring. For direct monitoring methods such as torque wrench method and ultrasonic measurement method, the monitoring accuracy will be affected by many factors such as screw size, screw stress-free length, monitoring environment and calibration method, resulting in large measurement errors and inability to accurately evaluate the tightening state of cable clamps. At the same time, this method is restricted by the monitoring principle, has a long monitoring cycle, cannot synchronously grasp the tightening state of the cable clamps of the entire bridge, and has a time lag, making it difficult to apply it to long-term monitoring. Indirect measurement methods such as inversion of screw axial force by measuring the strain on the outer surface of the cable clamp are affected by the position of the measuring point, the density of the measuring point, the environment, the calibration method, etc., and the screw axial force measurement error is relatively large. In addition, the installation of strain sensors is bound to damage the durability of the cable clamp such as corrosion resistance; at the same time, the strain sensors exposed at high altitude are greatly affected by severe weather such as hail, rain, snow, and strong winds, and the operating and maintenance costs are high. Therefore, at present, there is a lack of reliable means for long-term monitoring of the tightening status of the cable clamps, making it difficult to achieve long-term monitoring of the tightening status of the cable clamps and slippage warning, which will pose a safety hazard to the bridge structure. Summary of the invention

[0005] The present invention aims to solve the problem that there is a lack of reliable means for long-term monitoring of the tightening state of cable clamps at this stage, and it is difficult to achieve long-term monitoring of the tightening state of cable clamps and slip warning. A method for monitoring the tightening state of cable clamps of a suspension bridge and slip warning based on computer vision is now provided.

[0006] A method for monitoring the tightening state of a suspension bridge cable clamp based on computer vision comprises: respectively calculating the tooth gap spacing, radial pressure change and anti-sliding friction loss of the suspension bridge cable clamp to realize monitoring of the tightening state of the suspension bridge cable clamp;

[0007] The tooth gap distance is obtained by calculating through computer vision technology;

[0008] The cable clamp is divided into N segments along the axial direction, and the radial pressure variation of each segment is calculated according to the following formula:

[0009]

[0010] Among them, the expressions of intermediate variables Q and V are:

[0011]

[0012] Δσ iρ is the change in radial pressure of the i-th segment cable clamp, ΔC i is the change in the spacing between the teeth of the cable clamp in the i-th segment, The nominal radial elastic modulus of the main cable, D 0 is the diameter of the main cable in the initial state, P i1 is the initial preload force of the i-th segment cable clamp screw, H i1 is the initial cable force of the i-th segment cable clamp, R 0 is the radius of the main cable in the initial state, b i is the length of the cable clamp of the i-th segment, μ θ is the circumferential friction coefficient of the main cable, η is the uniform distribution coefficient of the sling force, δ is the wall thickness of the cable clip, and E c is the elastic modulus of the cable clip, θ 1 The angle between the line connecting the center of the main cable and the point where the cable clamp thickness changes and the Y axis, θ 2 is θ 1 The complementary angle of , i = 1, 2, ..., N;

[0013] The anti-sliding friction loss of each segment of the suspension bridge cable clamp is calculated according to the following formula:

[0014]

[0015] Among them, the expressions of intermediate variables U and W are:

[0016]

[0017] ΔF ifc is the anti-sliding friction loss of the i-th segment cable clamp, μ z It is the tangential friction coefficient between the contact interface between the main cable and the cable clamp.

[0018] Furthermore, the tooth gap spacing is obtained by calculating using computer vision technology, including:

[0019] The edge size of the cable clamp in the front view of the cable clamp teeth gap is collected by computer vision, and the absolute size of the tooth gap spacing distributed along the entire length of the tooth gap is calculated according to the pixel value between the teeth gaps;

[0020] Collect a perspective view of the gap between the teeth of the cable being tested;

[0021] The corresponding relationship between the edge size of the cable clamp in the front view and the actual size of the cable clamp tooth gap is established according to the angular relationship between the front view and the perspective view, thereby obtaining the tooth gap spacing of the measured cable clamp.

[0022] Furthermore, the change in the spacing between the teeth of the cable clamp in the i-th segment ΔC i The change in tooth spacing ΔC caused by the radial deformation of the cable clamp iρ The change in the spacing between the teeth of the cable clamp caused by the circumferential deformation of the cable clamp Superposition, and there are:

[0023]

[0024] Furthermore, the tooth gap spacing change ΔC caused by the radial deformation of the cable clamp is iρ The expression is:

[0025]

[0026] Furthermore, the change in the spacing between the teeth of the cable clamp caused by the circumferential deformation of the cable clamp is The expression is:

[0027]

[0028] Furthermore, the total loss of the cable clamp's anti-sliding friction resistance ΔF fc is the sum of the anti-sliding friction loss of each segment:

[0029]

[0030] The computer vision-based early warning method for cable clamp slippage of a suspension bridge includes:

[0031] The change in tooth gap spacing corresponding to the loss rate of anti-sliding friction resistance reaching 15% is used as the yellow warning value of cable clamp slippage.

[0032] The change in tooth gap spacing corresponding to the loss rate of anti-sliding friction resistance reaching 30% is used as the red warning value of cable clamp slippage.

[0033] The computer vision-based suspension bridge cable clamp fastening state monitoring method is used to monitor the fastening state of the suspension bridge cable clamp in real time to determine whether the suspension bridge cable clamp is in a slipping state.

[0034] The computer vision-based suspension bridge cable clamp tightening state monitoring and slip warning method described in the present invention utilizes non-contact monitoring technology based on computer vision, which is simple to operate and easy to maintain. Compared with traditional monitoring methods, it can greatly improve monitoring efficiency, reduce maintenance costs, reduce the risk of cable clamp slippage, and improve the safety and reliability of the in-service suspension bridge structure. The present invention can be used to synchronously grasp the tightening state of the cable clamps of the entire suspension bridge in real time, evaluate the loss of cable clamp anti-slip friction resistance, and provide a safety warning for cable clamp slippage; in addition, it can also be used to study the law of cable clamp anti-slip friction resistance loss and scientifically determine the cable clamp screw re-tightening maintenance cycle. The present invention is mainly used for cable clamp tightening state monitoring and cable clamp slippage warning of suspension bridges. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 Schematic diagram of the cable clamp holding the main cable, where (a) is the front view and (b) is the side view;

[0036] Figure 2 This is the front view of the cable clamp teeth;

[0037] Figure 3 This is a perspective view of the cable clamp teeth;

[0038] Figure 4 It is a schematic diagram of the equivalent model of the main cable in cylindrical coordinates;

[0039] Figure 5 It is a schematic diagram of the tooth gap spacing and the tightening state;

[0040] Figure 6 Schematic diagram of the cable clamp and main cable segment division;

[0041] Figure 7 This is the radial deformation force diagram of the i-th segment cable clamp;

[0042] Figure 8 This is the schematic diagram of the circumferential deformation and stress of the i-th segment cable clamp;

[0043] Fig. 9 To set the cable clamp slippage warning value based on the change in the cable clamp tooth gap spacing;

[0044] Screw 1, upper half cable clamp 2, main cable 3, tooth gap spacing 4, lower half cable clamp 5;

[0045] θ is the circumferential angle between the cable clamp micro segment and the X axis, dθ is the circumferential angle of the cable clamp micro segment, ΔP iB-A is the change in the preload force of the i-th segment cable clamp screw when the cable clamp decays from the tightening state A to the tightening state B, Δf iB-A is the change in the circumferential friction force on the inner wall of the i-th segment of the cable clamp when the cable clamp decays from the tightening state A to the tightening state B, ΔM iB-A is the change in bending moment of the i-th segment cable clamp section (X=0) when the cable clamp decays from the tightening state A to the tightening state B, ΔFiB-A It is the change of axial force of the cross section (X=0) of the i-th segment cable clamp when the cable clamp decays from the tightening state A to the tightening state B. DETAILED DESCRIPTION

[0046] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict. Specific implementation method one:

[0048] Schematic diagram of cable clamp fastening main cable Figure 1 As shown. The cable clamp-main cable anchoring system consists of a main cable 3, an upper half cable clamp 2, a lower half cable clamp 5 and a screw 1; wherein the lower half cable clamp 5 is connected to the sling. After the upper and lower half cable clamps are aligned with the main cable 3, a pre-tightening force is applied to the screw 1 that passes through the cable clamp, so that the cable clamp can be fastened to the main cable 3. According to Coulomb's law, under the radial pressure generated by the screw pre-tightening force of the cable clamp-main cable anchoring system, the contact interface between the cable clamp and the main cable will generate a frictional resistance that prevents the cable clamp from slipping, which is the cable clamp's anti-slip frictional resistance. The greater the cable clamp's anti-slip frictional resistance reserve, the better the cable clamp's tightening state. From Figure 1 It can be seen that the tooth gap distance 4 is closely related to the tightening state of the cable clamp: when the screw 1 is applied with sufficient preload, the cable clamp reaches a good tightening state, and the tooth gap distance is the smallest; when the preload force of the screw 1 decreases, the tightening state of the cable clamp deteriorates, and the tooth gap distance 4 increases. When the degree of decrease of the screw preload force at each position is inconsistent, the tooth gap distance 4 also changes unevenly along the length direction from left to right in the figure.

[0049] The computer vision-based suspension bridge cable clamp tightening state monitoring and slip warning method described in this embodiment uses computer vision technology to perform full-length distributed accurate recognition of the cable clamp tooth gap spacing 4, calculates the radial pressure of the cable clamp on the main cable 3 based on the recognized tooth gap spacing change, and further calculates the anti-slip friction resistance between the cable clamp and the main cable 3. The anti-slip friction resistance is compared with the sliding force on the cable clamp, and finally realizes the cable clamp tightening state warning.

[0050] The computer vision-based suspension bridge cable clamp fastening state monitoring and slippage warning method described in this embodiment includes:

[0051] 1. Recognition of the gap between cable clamp teeth based on computer vision

[0052] like Figure 2As shown, the edge size of the cable clamp in the front view of the cable clamp tooth gap is known. In the acquired cable clamp tooth gap image, the corresponding relationship between the actual size and the pixel value can be obtained, so that the absolute size of the tooth gap spacing distributed along the entire length of the tooth gap can be calculated based on the pixel value between the tooth gaps.

[0053] like Figure 3 As shown in the figure, in actual shooting, it is often impossible to obtain a front view of the cable clamp teeth gap, but a perspective view obtained from a specific angle. In the perspective view, the size and angle of the cable clamp edge can still establish a corresponding relationship with the actual size, so that the absolute size of the tooth gap spacing distributed along the entire length of the tooth gap can also be calculated based on the pixel value between the teeth gaps.

[0054] 2. Calculation of radial pressure of cable clamp based on tooth gap spacing

[0055] like Figure 4 As shown in the figure, the inhomogeneous main cable 3 is considered as a whole, and an equivalent uniform continuum is used to replace the average characteristics of the complex main cable structure, and the cylindrical coordinate system is used. Under this condition, a triaxial anisotropic main cable equivalent model is established. The radial strain ε ρ It can be expressed as:

[0056]

[0057] in, is the nominal radial elastic modulus of the main cable, σ ρ is the radial pressure.

[0058] like Figure 5 As shown in the figure, the change of the tightening state of the cable clamp will cause the corresponding change of the radial pressure of the main cable, and the cable clamp will then undergo radial and circumferential deformation, causing the change of the tooth gap spacing. According to the different stages of the cable clamp-main cable anchoring system, it is divided into three states: initial state, tightening state A and tightening state B.

[0059] Initial state: the state when the cable clamp is not tightened. At this time, the radial pressure is 0.

[0060] Tightening state A: Under the action of the initial preload of screw 1 and the initial sling force, the cable clamp reaches the tightening state. At this time, the radial pressure of the main cable is σ ρA , the main cable diameter is D A , the tooth gap spacing is C A In general, the initial screw preload and initial cable force can be taken as the design preload and cable force applied when the bridge is completed or the screw preload and cable force known during operation.

[0061] Tightening state B: a state reached after the cable clamp tightens. At this time, the radial pressure of the main cable is σ ρB , the main cable diameter is DB , the tooth gap spacing is C B .

[0062] like Figure 6 As shown, in actual projects, the degree of reduction of the screw preload force at each position of the cable clamp is not consistent, and the reduction amount of the interface radial pressure in the area represented by each row of screws is not the same. In this embodiment, the cable clamp and the main cable 3 are divided into N segments along the axial direction according to the area shared by a single row of screws, and the change in the tooth gap spacing 4 caused by the radial pressure change in each segment is calculated respectively.

[0063] When the cable clamp decays from the tightening state A to the tightening state B, the change in the spacing between the teeth of the i-th segment cable clamp is ΔC i It can be obtained by formula (2):

[0064] ΔC i =C iB -C iA (2)

[0065] Among them, C iA and C iB are the spacings of the cable clamp teeth of the i-th segment in the tightening state A and the tightening state B, respectively, i=1, 2, ..., N.

[0066] like Figure 7 As shown in the figure, in the calculation process of radial deformation of the cable clamp caused by radial pressure change, the circumferential length of the cable clamp cross section is kept unchanged, the cable clamp and the main cable cross section and the external load are all axially symmetrically distributed, the i-th segment cable clamp and the main cable 1 / 4 cross section are taken as the analysis objects, and the force balance relationship is established in the Y-axis direction. The calculated change in the tooth gap spacing is shown in formula (3):

[0067]

[0068] Among them, D 0 is the diameter of the main cable in the initial state, R 0 is the radius of the main cable in the initial state, μ θ is the circumferential friction coefficient of the main cable, b i is the length of the cable clamp in the i-th segment, P iA is the preload force of the i-th segment cable clamp screw in the tightening state A, H iA is the sling force of the i-th segment in the clamping state A, Δσ iρB-A is the change in radial pressure of the i-th segment cable clamp when the cable clamp decays from the tightening state A to the tightening state B, and η is the uniform distribution coefficient of the sling force.

[0069] like Figure 8 As shown in the figure, in the calculation process of the circumferential deformation of the cable clamp caused by the change of radial pressure, the i-th segment cable clamp and the 1 / 4 cross section of the main cable are taken as the analysis objects, and the force balance relationship is established. The calculated change of the tooth gap spacing is shown in formula (4):

[0070]

[0071] Among them, δ is the wall thickness of the cable clamp, E c is the elastic modulus of the cable clip, θ 1 The angle between the line connecting the center of the main cable and the point where the cable clamp thickness changes and the Y axis, θ 2 is θ 1 The remaining angle.

[0072] The change of the spacing between the teeth of the cable clamp in the i-th segment ΔC i The change in tooth spacing ΔC caused by the radial deformation of the cable clamp iρ The change in the spacing between the teeth of the cable clamp caused by the circumferential deformation of the cable clamp Superposition:

[0073]

[0074] Combining formula (2) and (5), we can get:

[0075]

[0076] Substituting equations (3) and (4) into equation (6), we can obtain:

[0077]

[0078] in,

[0079]

[0080] 3. Calculation of anti-sliding friction based on cable clamp

[0081] The radial pressure change of the main cable is Δσ iρB-A When the anti-sliding friction loss of the i-th segment cable clamp is ifc It can be calculated by formula (8):

[0082] ΔF ifc =2πR 0 b i Δσ iρ B-A μ z (8)

[0083] Among them, μ z It is the tangential friction coefficient between the contact interface between the main cable and the cable clamp.

[0084] Establish the anti-sliding friction loss of the i-th segment cable clamp ΔF ifc The change in the spacing between the i-th segment cable clamp teeth ΔC i The relationship is:

[0085]

[0086] in,

[0087] Total loss of cable clamp anti-sliding friction ΔF fc The sum of the anti-sliding friction loss of each segment cable clamp:

[0088]

[0089] Specific implementation method 2: The computer vision-based suspension bridge cable clamp slippage warning method described in this implementation method includes:

[0090] According to the Technical Specifications for Maintenance of Highway Cable Structure Bridges (JTG / T 5122):

[0091] Preventive maintenance should be taken for the cable clamp, requiring that the tightening force of the cable clamp screw should be maintained at no less than 70% of its installation design value.

[0092] According to the relationship between the change in tooth gap spacing and the total loss of the anti-slip friction resistance of the cable clamp, the change in tooth gap spacing corresponding to the anti-slip friction resistance loss rate reaching 15% can be used as the yellow warning value of cable clamp slippage, reminding the relevant maintenance departments that the tightening state of the cable clamp has weakened and requires sufficient attention.

[0093] The change in tooth gap spacing corresponding to when the anti-slip friction resistance loss rate reaches 30% is used as the red warning value for cable clamp slippage, reminding the relevant maintenance departments that the anti-slip friction resistance loss of the cable clamp has reached 30%, there is a risk of slippage, and necessary maintenance measures must be taken. Specific implementation method three:

[0095] Taking a suspension bridge cable clamp as an example, the main cable uses galvanized high-strength steel wire with a standard strength of 1670MPa and a designed elastic modulus of 2.0×10 5 MPa. After tightening, the main cable diameter is 391mm (void ratio is 20%), and the diameter at the cable clamp is 386mm (void ratio is 18%). The cable clamp adopts ZG20Mn cast steel structure, the screw rod adopts 40CrNiMoA alloy steel, the initial screw rod preload is 660kN, and the initial sling force is 4070kN; the circumferential and axial friction coefficients are both 0.15.

[0096] Use a drone or a fixed camera to collect high-definition images of the spacing between the teeth of the cable clamp, combine the edge monitoring algorithm to extract the upper and lower edges of the teeth of the cable clamp, and use the sub-pixel algorithm to finely calculate the pixel spacing of the teeth. At the same time, the pixel spacing from the upper edge of the cable clamp to the upper edge of the teeth is extracted, and combined with the known actual spacing from the upper edge of the cable clamp to the upper edge of the teeth, the continuous displacement distribution of the teeth spacing along the length direction of the cable clamp is obtained, so as to more accurately identify the changes in the teeth spacing.

[0097] According to formula (9), the relationship curve between the change in tooth gap spacing and the anti-sliding friction loss rate can be obtained, as shown in Figure 8 The change in the tooth gap distance of 0.19 mm is regarded as the yellow warning value of the cable clamp slippage; the change in the tooth gap distance of 0.38 mm is regarded as the red warning value of the cable clamp slippage.

[0098] The change in the tooth gap spacing based on computer vision recognition is compared with Figure 8 The cable clamp slip warning value relationship diagram shown can obtain the anti-slip friction loss rate corresponding to a certain tooth gap spacing change. According to the set cable clamp slip warning value, the cable clamp tightening state, anti-slip friction current status and slip risk degree are judged.

[0099] In summary, the present invention uses the spacing between the cable clamp teeth as an evaluation index of the tightening state of the cable clamp, and uses the changes in the spacing between the cable clamp teeth to invert the tightening state of the cable clamp, and obtains the technical status of the anti-slip friction resistance of the cable clamp-main cable anchoring system. Specifically, computer vision technology is used to accurately identify the changes in the spacing between the cable clamp teeth, thereby achieving real-time monitoring of the tightening state of the cable clamp and slip warning. As a long-term monitoring and early warning method that can replace traditional screw axial force monitoring, it has the characteristics of high monitoring accuracy, high speed, and short cycle. It can synchronously control the tightening state of the cable clamps of the entire bridge and reduce the risk of cable clamp slippage. At the same time, the present invention does not require the deployment of sensors, does not affect the durability of the cable clamps and the main cables, does not require manual monitoring tooling measures, does not affect traffic, can greatly reduce operation and maintenance costs, and has significant social and economic benefits.

[0100] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. It should therefore be understood that many modifications may be made to the exemplary embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in a manner different from that described in the original claims. It should also be understood that the features described in conjunction with a single embodiment may be used in other described embodiments.

Claims

1. A method for monitoring the fastening state of cable clamps of a suspension bridge based on computer vision, characterized in that: include: The tooth gap spacing, radial pressure change and anti-sliding friction loss of the suspension bridge cable clamp are calculated respectively to monitor the tightening state of the suspension bridge cable clamp; The tooth gap distance is obtained by calculating through computer vision technology; The cable clamp is divided into N segments along the axial direction, and the radial pressure variation of each segment is calculated according to the following formula: Among them, the expressions of intermediate variables Q and V are: Δσ iρ is the change in radial pressure of the i-th segment cable clamp, ΔC i is the change in the spacing between the teeth of the cable clamp in the i-th segment, is the nominal radial elastic modulus of the main cable, D0 is the diameter of the main cable in the initial state, P i1 is the initial preload force of the i-th segment cable clamp screw, H i1 is the initial cable force of the i-th segment cable clamp, R0 is the radius of the main cable in the initial state, b i is the length of the cable clamp of the i-th segment, μ θ is the circumferential friction coefficient of the main cable, η is the uniform distribution coefficient of the sling force, δ is the wall thickness of the cable clip, and E c is the elastic modulus of the cable clamp, θ1 is the angle between the line connecting the center of the main cable and the point where the thickness of the cable clamp changes and the Y axis, θ2 is the complementary angle of θ1, i=1,2,...,N; The anti-sliding friction loss of each segment of the suspension bridge cable clamp is calculated according to the following formula: Among them, the expressions of intermediate variables U and W are: ΔF ifc is the anti-sliding friction loss of the i-th segment cable clamp, μ z It is the tangential friction coefficient between the contact interface between the main cable and the cable clamp.

2. The computer vision-based method for monitoring the fastening state of a suspension bridge cable clamp according to claim 1, characterized in that: The step of calculating the tooth gap distance by computer vision technology includes: The edge size of the cable clamp in the front view of the cable clamp teeth gap is collected by computer vision, and the absolute size of the tooth gap spacing distributed along the entire length of the tooth gap is calculated according to the pixel value between the teeth gaps; Collect a perspective view of the gap between the teeth of the cable being tested; The corresponding relationship between the edge size of the cable clamp in the front view and the actual size of the cable clamp tooth gap is established according to the angular relationship between the front view and the perspective view, thereby obtaining the tooth gap spacing of the measured cable clamp.

3. The method for monitoring the fastening state of suspension bridge cable clamps based on computer vision according to claim 1, characterized in that: The change in the spacing between the teeth of the i-th segment cable clamp ΔC i The change in tooth spacing ΔC caused by the radial deformation of the cable clamp iρ The change in the spacing between the teeth of the cable clamp caused by the circumferential deformation of the cable clamp Superposition, and there are:

4. The computer vision-based method for monitoring the fastening state of a suspension bridge cable clamp according to claim 3, characterized in that: The change in tooth gap spacing ΔC caused by the radial deformation of the cable clamp iρ The expression is:

5. The computer vision-based method for monitoring the fastening state of a suspension bridge cable clamp according to claim 3, characterized in that: The change in the spacing between the teeth of the cable clamp caused by the circumferential deformation of the cable clamp The expression is:

6. The method for monitoring the fastening state of suspension bridge cable clamps based on computer vision according to claim 1, characterized in that: Total loss of cable clamp anti-sliding friction ΔF fc is the sum of the anti-sliding friction loss of each segment:

7. A computer vision-based early warning method for cable clamp slippage in a suspension bridge, characterized in that: include: The change in tooth gap spacing corresponding to the loss rate of anti-sliding friction resistance reaching 15% is used as the yellow warning value of cable clamp slippage. The change in tooth gap spacing corresponding to the loss rate of anti-sliding friction resistance reaching 30% is used as the red warning value of cable clamp slippage. The computer vision-based suspension bridge cable clamp tightening state monitoring method as described in any one of claims 1 to 6 is used to monitor the tightening state of the suspension bridge cable clamp in real time to determine whether the suspension bridge cable clamp is in a slipping state.

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