Suspension bridge suspender damage identification and positioning method based on main cable form variation

Abstract

The invention relates to the technical field of suspension bridge suspenders, and discloses a suspension bridge suspender damage identification and positioning method based on main cable form variation, and the method comprises the following steps: S1, obtaining the position of a central point of a connecting line between intersection points of main cables at two sides; s2, obtaining the relative displacement of the intersection point of the main cable of the suspender; s3, repeating S1 to S2 to obtain corresponding main cable intersection point relative displacement of each suspender of the suspension bridge, and according to the relative displacement of each main cable intersection point of the suspension bridge, obtaining a main cable intersection point relative displacement change diagram in which the abscissa is the serial number of the suspender and the ordinate is the relative displacement; s4, when the lines in the main cable intersection point relative displacement change diagram are M-shaped, the suspender damage is the vertical damage, and the corresponding abscissa at the inward bending position in the M-shaped lines is the suspender with the corresponding damage; and when the line in the main cable intersection point relative displacement change diagram is W-shaped, the hanger rod damage is the transverse damage, and the hanger rod with the corresponding damage is the corresponding abscissa at the outward bending position in the W-shaped line. The suspender condition can be known in time, and the suspension bridge is prevented and maintained.

Description

Technical Field

[0001] This invention relates to the field of suspension bridge hanger technology, specifically to a method for identifying and locating suspension bridge hanger damage based on main cable morphological variations. Background Technology

[0002] As a key component connecting the main cable and the main beam of a suspension bridge, the safety performance of the suspender is crucial to the overall bridge. Most accidents caused by suspender problems in suspension bridges at home and abroad are due to broken suspender wires, loose suspender anchorages (the anchorages of the suspender can become loose due to reduced clamping force caused by corrosion, loosening of clamping plates, etc.), and slippage of cable clamps (the suspender and the main cable are connected by cable clamps, and when the bolts of the cable clamps are corroded or loose, it will cause the cable clamps to slip).

[0003] Damage to suspenders can cause significant changes in suspender force, reducing the safety reserve of suspenders and main beams, and even significantly impacting the normal use and safety performance of suspension bridges. Identifying and locating suspender damage can prevent catastrophic accidents in a timely manner, extend the bridge's service life, and reduce total life-cycle costs. For example, by accurately locating damage and taking targeted repair measures (such as replacing suspenders and anti-corrosion treatment), the cost of replacing a single suspender is only one-thousandth of the total bridge reconstruction cost, but it can significantly extend the overall lifespan of the bridge.

[0004] Damage identification and localization of suspension bridge hangers is a comprehensive diagnostic process integrating multiple technologies. Existing technologies first use vibration analysis to measure the hanger frequency and calculate its tension, enabling rapid surveying and preliminary localization of internal damage such as wire breakage and corrosion. Secondly, drones equipped with high-definition cameras are used for visual inspection, combined with artificial intelligence image recognition technology to accurately identify and locate defects such as cracks and corrosion on the hanger surface.

[0005] However, vibration analysis is susceptible to environmental factors (such as temperature changes), leading to reduced frequency measurement accuracy. This is especially true in the early stages of boom damage, when stiffness and mass changes are minimal and frequency changes are not significant, making accurate early damage identification difficult. Secondly, visual inspection relies on manual interpretation or AI image recognition, which cannot effectively detect non-surface-visible damage such as internal anchor loosening or slippage of cable clamps. Furthermore, drone inspection is greatly limited by weather conditions and has blind spots. In addition, existing methods are mostly designed for single damage types (such as identifying only broken wires or detecting only cable clamp slippage), lacking the ability to comprehensively distinguish different damage modes (vertical damage such as broken wires and anchor loosening, and lateral damage such as cable clamp slippage), making it difficult to systematically assess the overall health status of the boom and potentially leading to missed detections or misjudgments. Summary of the Invention

[0006] To overcome the shortcomings of existing technologies, the present invention aims to provide a method for identifying and locating suspension bridge hanger damage based on main cable morphological variations. This method avoids the influence of environmental factors, enables timely knowledge of the suspension bridge hanger condition, and allows for assessment of the safety performance of the suspension bridge. It also enables preventive maintenance, extends the bridge's service life, and reduces lifecycle costs.

[0007] The technical solution adopted in this invention is as follows: a method for identifying and locating damage to suspension bridge hangers based on main cable morphological variations, comprising the following steps:

[0008] S1: Obtain the center point of the line connecting the intersection points of the main cables on both sides of one of the suspension bridge's suspenders by passing through the intersection points of the main cables on both sides of the suspender.

[0009] S2: The intersection of the main cables of the suspension bridge's gantry. The initial displacement of the main cable intersection point of the suspender is obtained by measuring the difference between the actual position at a given time and the height of the center point. This displacement is then measured across the suspension bridge. The difference between the actual position and the center point height at a given time point yields the deformation displacement at the intersection of the main cable of the suspender. The difference between the deformation displacement and the initial displacement is the relative displacement.

[0010] S3: Repeat S1-S2 to obtain the relative displacement of the main cable intersection point of each suspender of the suspension bridge, and obtain the relative displacement change diagram of the main cable intersection point with the suspender number on the horizontal axis and the relative displacement on the vertical axis based on the relative displacement of each main cable intersection point of the suspension bridge.

[0011] S4: When the line in the relative displacement change graph of the main cable intersection point is M-shaped, the damage to the suspender is vertical. The horizontal coordinate of the inward bend in the M-shaped line is the corresponding damaged suspender.

[0012] When the line in the relative displacement change graph of the main cable intersection point is W-shaped, the damage to the suspender is lateral damage. The horizontal coordinate of the outward bend in the W-shaped line is the corresponding damaged suspender.

[0013] In a preferred embodiment of the present invention, when the line in the relative displacement change graph of the main cable intersection is M-shaped, the vertical damage includes broken wires of the suspender or loosening of the anchor.

[0014] In a preferred embodiment of the present invention, when the line in the relative displacement change graph of the main cable intersection is W-shaped, the lateral damage includes cable clamp slippage.

[0015] In a preferred embodiment of the present invention, in S4, if the line in the relative displacement change diagram of the main cable intersection point only shows an M-shape, the damage to the suspender is a broken wire of a single suspender or a loose anchor of a single suspender.

[0016] If the lines in the diagram showing the relative displacement of the main cable intersection point appear as multiple M-shapes, the damage to the suspenders is due to multiple broken wires in the suspenders or multiple loose suspender anchors.

[0017] In a preferred embodiment of the present invention, in S4, if the line in the relative displacement change diagram of the main cable intersection point only presents a W shape, the damage to the suspender is a single cable clamp slippage.

[0018] If the lines in the diagram showing the relative displacement of the main cable intersection point appear as multiple W shapes, the damage to the suspender is due to the slippage of multiple cable clamps.

[0019] In a preferred embodiment of the present invention, when the line in the relative displacement change diagram of the main cable intersection point is M-shaped, if the difference between the relative displacement of the main cable intersection point of one of the hangers and the relative displacement of the main cable intersection point of the adjacent hangers is less than a preset threshold, then the hanger is a damaged hanger, that is, an inward bending point of the M-shape, as shown in formulas (1) and (2).

[0020] (1),

[0021] (2),

[0022] In formulas (1) and (2), For the first The relative displacement of the main cable intersection point of the No. 1 suspender. For the first The relative displacement of the main cable intersection point of the No. 1 suspender. For the first The relative displacement of the main cable intersection point of the No. 1 suspender. This is a preset threshold.

[0023] In a preferred embodiment of the present invention, when the line in the relative displacement change diagram of the main cable intersection point is W-shaped, if the difference between the relative displacement of the main cable intersection point of one of the hangers and the relative displacement of the main cable intersection point of the adjacent hangers is greater than a preset threshold, then the hanger is a damaged hanger, that is, a W-shaped outward bending point, as shown in formulas (3) and (4).

[0024] (3),

[0025] (4),

[0026] In formulas (3) and (4), For the first The relative displacement of the main cable intersection point of the No. 1 suspender. For the first The relative displacement of the main cable intersection point of the No. 1 suspender. For the first The relative displacement of the main cable intersection point of the No. 1 suspender. This is a preset threshold.

[0027] In a preferred embodiment of the present invention, in S4, half of the initial displacement of the main cable intersection point of the suspender is set as the severe damage threshold. If the absolute value of the relative displacement of the main cable intersection point corresponding to the inward bending point in the M-shape is less than the preset severe damage threshold, then the suspender is partially broken. If the absolute value of the relative displacement of the main cable intersection point corresponding to the inward bending point in the M-shape is greater than the preset severe damage threshold, then the anchor is loose or the suspender is completely broken.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] As a key component connecting the main cable and main beam of a suspension bridge, the safety performance of the suspenders directly determines the overall stability of the bridge structure. However, due to the combined effects of alternating loads, environmental corrosion, and material fatigue on the suspenders over long periods, internal damage (such as wire breakage and loosening of the anchorage zone) is often difficult to detect through visual inspection. It is necessary to assess their health status by real-time monitoring of changes in the axial force (i.e., suspender force). Since the suspender force is linearly related to the relative displacement of the main cable intersection point, the suspender force can be indirectly obtained by measuring the relative displacement of the main cable intersection point. This invention effectively reduces the influence of temperature on the relative deformation of the bridge when monitoring the combined effects of suspender damage through the relative displacement of the main cable intersection point, making the characteristics of the damage more obvious and enabling accurate identification and location of suspender damage. Specifically, it eliminates common-mode interference: under the influence of temperature changes, wind loads, or overall traffic flow, bridges undergo significant overall deformation (on the order of meters). Directly measuring absolute coordinates (such as GPS) makes it difficult to extract minute millimeter-level damage deformations from the huge overall deformation. This invention employs "relative displacement" and utilizes the differential principle to automatically eliminate the influence of the overall vertical displacement of the bridge. This is equivalent to establishing a "floating coordinate system" that moves with the entire bridge, thereby enabling the keen detection of minute morphological distortions caused only by local damage.

[0030] Visual recognition cannot replace it: Traditional machine vision (photography) is greatly affected by lighting, fog, and occlusion, and it is difficult to distinguish minute three-dimensional spatial morphological variations; while the physical measurement accuracy of this method can reach 0.1mm level, with the advantages of all-weather and high robustness. Attached Figure Description

[0031] Figure 1 This is a flowchart of the method for identifying and locating damage to suspension bridge hangers based on main cable morphology variations, as per the present invention.

[0032] Figure 2 This is a schematic diagram of the relative displacement of the main cable intersection point in the suspension bridge hanger damage identification and location method based on main cable morphology variation of the present invention;

[0033] Figure 3 This is a diagram showing the relative displacement change of the main cable intersection point of a single broken wire in a suspension bridge suspender in the method for identifying and locating suspension bridge suspender damage based on main cable morphology variation, as described in this invention.

[0034] Figure 4 This is a diagram showing the relative displacement of the intersection point of multiple broken wires of the main cable in the suspension bridge suspender damage identification and location method based on main cable morphology variation of the present invention.

[0035] Figure 5 This is a diagram showing the relative displacement change of the main cable intersection point when a single suspender anchor is detached, in the suspension bridge suspender damage identification and location method based on main cable morphology variation of this invention;

[0036] Figure 6 This is a diagram showing the relative displacement change of the main cable intersection point when multiple anchorages are loosened in the suspension bridge suspender damage identification and location method based on main cable morphology variation of the present invention;

[0037] Figure 7 This is a diagram showing the relative displacement change of the intersection point of a single cable clamp slipping main cable in the suspension bridge hanger damage identification and location method based on main cable morphology variation of the present invention;

[0038] Figure 8 This is a diagram showing the relative displacement changes of multiple cable clamp slippage main cable intersection points in the suspension bridge hanger damage identification and location method based on main cable morphology variation of the present invention;

[0039] Figure 9 This is a diagram showing the relative displacement of the main cable intersection point of a single broken wire in suspension bridge hangers #4, #23, #34, and #55 in the suspension bridge hanger damage identification and location method based on main cable morphology variation of the present invention.

[0040] Figure 10 This is a displacement diagram of the main cable intersection point before and after multiple hanger wires breakage in the suspension bridge hanger damage identification and location method based on main cable morphology variation of the present invention;

[0041] Figure 11 This is a diagram showing the relative displacement changes at the main cable intersection points of single hangers #4, #23, #34, and #55 hangers where the anchorages of individual hangers have become loose, in the suspension bridge hanger damage identification and location method based on main cable morphology variation of this invention.

[0042] Figure 12 This is a displacement diagram of the main cable intersection point before and after the anchorage of multiple suspension rods loosened in the suspension bridge suspension rod damage identification and location method based on main cable morphology variation of the present invention;

[0043] Figure 13 This is a diagram showing the relative displacement changes at the intersection points of the main cable and cable clamps of hangers #3, #13, and #23 in the suspension bridge hanger damage identification and location method based on main cable morphology variation of this invention.

[0044] Figure 14 This invention provides a method for identifying and locating damage to suspension bridge hangers based on main cable morphology variations, which includes displacement diagrams of the main cable intersection points before and after slippage of multiple cable clamps.

[0045] Figure 15This is a schematic diagram of the structure of the first connecting component, displacement sensor, and second connecting component in the measurement system of the present invention for measuring the relative displacement of the intersection point of the main cables of a suspension bridge;

[0046] Figure 16 This is a schematic diagram of the first connecting component, displacement sensor, and second connecting component from another angle in the measurement system of the present invention for measuring the relative displacement of the intersection point of the main cables of a suspension bridge.

[0047] Figure 17 This is another angular structural diagram of the first connecting component, displacement sensor, and second connecting component in the measurement system of the present invention for measuring the relative displacement of the intersection point of the main cables of a suspension bridge.

[0048] Figure 18 This is a schematic diagram of the structure at position A of the present invention;

[0049] Figure 19 This is a schematic diagram of the structure at position B of the present invention;

[0050] Figure 20 This is a schematic diagram of the first connecting component, displacement sensor, and second connecting component at another angle in the measurement system of the present invention for measuring the relative displacement of the intersection point of the main cables of a suspension bridge.

[0051] Figure 21 This is a schematic diagram of the structure at position C of the present invention;

[0052] Figure 22 This is a schematic diagram of the installation of displacement sensors and auxiliary cables in the measurement system of the present invention for measuring the relative displacement of the intersection of the main cables of a suspension bridge. Detailed Implementation

[0053] Typical embodiments embodying the features and advantages of the present invention will be specifically described in the following description. It should be understood that the present invention can have various variations in different embodiments without departing from the scope of the present invention, and the descriptions and illustrations herein are for illustrative purposes only and not intended to limit the present invention.

[0054] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0055] Explanation: The main cable junction is the point where the main cable and the suspender are connected. The main cable and the suspender are connected by a cable clamp, which is the junction of the main cable and the cable clamp.

[0056] This embodiment discloses a method for identifying and locating damage to suspension bridge hangers based on main cable morphological variations, such as... Figure 1 As shown, it includes the following steps:

[0057] S1: Obtain the center point of the line connecting the two main cable intersections through the intersection of the two main cables on one of the suspension bridge's hangers;

[0058] In this embodiment, as Figure 2 As shown, the boom The intersection points of the main cables on both sides are respectively , Main cable intersection Intersection with main cable The position of the center point of the straight line between them is .

[0059] S2: The intersection of the main cables of the suspension bridge's gantry. The initial displacement of the main cable intersection point of the suspender is obtained by measuring the difference between the actual position at a given time and the height of the center point. This displacement is then measured across the suspension bridge. The difference between the actual position and the center point height at a given time point yields the deformation displacement at the intersection of the main cable of the suspender. The difference between the deformation displacement and the initial displacement is the relative displacement.

[0060] In this embodiment, the main cable of the suspension bridge is located at the intersection of the main cable and the suspender. The initial displacement of the main cable intersection point of the suspender is obtained by the difference between the actual position and the height of the center point at the time point. The main cable of the suspension bridge intersects at the point where the suspender cable meets the main cable. The difference in height between the actual position at a given time point and the center point position yields the deformation displacement at the intersection of the main cable and the suspender. The difference between the deformation displacement and the initial displacement is the relative displacement. .

[0061] S3: Repeat S1-S2 to obtain the relative displacement of the main cable intersection points of each suspender of the suspension bridge. Based on the relative displacement of the main cable intersection points, obtain a graph showing the change in relative displacement of the main cable intersection points, with the suspender number on the horizontal axis and the relative displacement on the vertical axis. Figure 3-8 As shown;

[0062] S4: When the line in the relative displacement change graph of the main cable intersection point is M-shaped, the damage to the suspender is vertical. The horizontal coordinate of the inward bend in the M-shaped line is the corresponding damaged suspender.

[0063] In this embodiment, when the line in the relative displacement change diagram of the main cable intersection point is M-shaped, if the difference between the relative displacement of the main cable intersection point of one of the hangers and the relative displacement of the main cable intersection point of the adjacent hangers is less than a preset threshold, then the hanger is a damaged hanger, that is, the inward bending point of the M-shape, as shown in formulas (1) and (2).

[0064] (1),

[0065] (2),

[0066] In formulas (1) and (2), For the first The relative displacement of the main cable intersection point of the No. 1 suspender. For the first The relative displacement of the main cable intersection point of the No. 1 suspender. For the first The relative displacement of the main cable intersection point of the No. 1 suspender. This is a preset threshold.

[0067] A value greater than zero indicates that the displacement of point i is significantly smaller than (more negative) than that of its two adjacent points, forming a local minimum (trough). At this point, the i-th rod is the point of inward bending (damage point). In this embodiment, a significant negative peak (downward abrupt change) appears at the damage point i, while smaller positive peaks appear at its two adjacent points i−1 and i+1 as compensation.

[0068] In this embodiment, when the line in the relative displacement change graph of the main cable intersection is M-shaped, vertical damage includes broken wires in the suspender or loosening of the anchor, such as... Figure 3 As shown.

[0069] In this embodiment, in S4, if the line in the relative displacement change graph of the main cable intersection only shows an M-shape, the damage to the suspender is either a broken wire in a single suspender or a loose anchor in a single suspender. Figure 5 As shown;

[0070] If the lines in the relative displacement change graph of the main cable intersection point show multiple M-shapes, the damage to the suspenders is due to multiple broken wires in the suspenders or multiple loose suspender anchors. Figure 6 As shown.

[0071] In this embodiment, in S4, half of the initial displacement of the main cable intersection point of the suspender is set as the severe damage threshold. If the absolute value of the relative displacement of the main cable intersection point corresponding to the inward bend point in the M-shape is less than the preset severe damage threshold, then the suspender is partially broken. If the absolute value of the relative displacement of the main cable intersection point corresponding to the inward bend point in the M-shape is greater than the preset severe damage threshold, then the anchor is loose or the suspender is completely broken.

[0072] When the line in the relative displacement change graph of the main cable intersection point is W-shaped, the damage to the suspender is lateral damage. The horizontal coordinate of the outward bend in the W-shaped line is the corresponding damaged suspender.

[0073] When the line in the diagram of the relative displacement of the main cable intersection point is W-shaped, if the difference between the relative displacement of the main cable intersection point of one of the hangers and the relative displacement of the main cable intersection point of the adjacent hanger is greater than a preset threshold, then the hanger is a damaged hanger, that is, a W-shaped outward bending point, as shown in formulas (3) and (4).

[0074] (3),

[0075] (4),

[0076] In formulas (3) and (4), For the first The relative displacement of the main cable intersection point of the No. 1 suspender. For the first The relative displacement of the main cable intersection point of the No. 1 suspender. For the first The relative displacement of the main cable intersection point of the No. 1 suspender. This is a preset threshold.

[0077] A value greater than zero indicates that the displacement of point i is significantly greater than (correcting) the displacement of the two adjacent points, forming a local maximum (peak). At this point, the i-th rod is the point of outward bending (damage point). In this embodiment, a significant positive peak (upward abrupt change) appears at the damage point i, while negative peaks (downward depressions) appear at its two adjacent points i−1 and i+1.

[0078] When the line in the relative displacement change graph of the main cable intersection is W-shaped, lateral damage includes cable clamp slippage, such as... Figure 4 As shown.

[0079] In this embodiment, in S4, if the line in the relative displacement change graph of the main cable intersection only shows a W shape, the damage to the suspender is a single cable clamp slippage, such as... Figure 7 As shown;

[0080] If the lines in the relative displacement change graph of the main cable intersection point show multiple W-shapes, the damage to the suspender is due to slippage of multiple cable clamps. Figure 8 As shown.

[0081] In this embodiment, since the distribution of suspender force directly determines the overall and local geometry of the main cable, abnormal suspender force can lead to structural safety risks (such as suspender breakage), main cable deformation, and amplify fatigue effects, shortening suspender life. However, there is currently no effective cable force measurement method to solve the problem of difficulty in measuring suspender force in the mid-span area. Most abnormal suspender force in suspension bridges is caused by suspender damage. In order to detect abnormal suspender force in a timely manner, this invention reflects the change in suspender force by identifying the relative displacement of the main cable intersection point, and identifies and locates the type and corresponding location of damage by using the image of the relative displacement of the main cable intersection point.

[0082] Furthermore, since the changes in suspender force and the deformation of the main cable intersection are highly sensitive, and there is a linear relationship between the deformation of the main cable intersection and the changes in suspender force, this invention analyzes the relative displacement of the main cable intersection to obtain the suspender damage situation, quickly identify the type of suspender damage and locate the location of the suspender damage.

[0083] The impact of a broken wire in a single suspender rod on the deformation of the main cable intersection was verified as follows.

[0084] This invention verifies the relationship between broken wires in the suspender and deformation at the junction of the main cable by using a finite element model for analysis and simulation, and by simulating suspender damage through reduction of the suspender's cross-sectional area. In the numerical simulation, the impact of different degrees of damage on suspender displacement varies significantly; therefore, different degrees of suspender wire breakage are simulated based on different reductions in the suspender's cross-sectional area. Four different reduction degrees—20%, 40%, 60%, and 80%—are set to verify the influence of broken suspender wires on the deformation at the junction of the main cable.

[0085] Finite element model analysis and simulation of hanger wire breakage: This damage is simulated by directly modifying the cross-sectional area property of the element representing the hanger in the finite element model. For example, to simulate 40% wire breakage damage, the cross-sectional area parameter of the hanger element is set to 60% of its original value (100% - 40%). After modification, a new nonlinear structural analysis is performed to obtain the equilibrium state and internal force distribution of the bridge under this damage state.

[0086] Finite element model analysis and simulation of anchorage slippage: This damage is simulated by modifying the "stress-free length" parameter of the hanger cable element. First, the internal force T and geometric length L of each hanger in a healthy state are obtained through "bridge forming analysis". The software can automatically calculate the corresponding stress-free length L0 based on the material's elastic modulus E and cross-sectional area A. Simulating anchorage slippage involves artificially adding a specific length value (e.g., 5 cm or 10 cm) to this calculated L0. When the model is rebalanced with this new, longer stress-free length, the hanger element will exhibit relaxation, and its internal force will decrease accordingly, thus accurately simulating the physical effects of anchorage slippage.

[0087] Finite element model analysis and simulation of cable clamp slippage: The damage does not directly modify the boom element, but rather the main cable element connected to the boom. The essence of cable clamp slippage is the longitudinal movement of the boom connection point along the main cable. To simulate this process, element temperature loads need to be applied to the main cable elements on both sides of the damaged boom i (i.e., the segments of the main cable between boom i−1 and i, and between i and i+1). For example, to simulate a slippage distance X to the right, a positive temperature load is applied to the left main cable element, increasing its stress-free length by X due to thermal expansion; simultaneously, a negative temperature load is applied to the right main cable element, decreasing its stress-free length by X due to thermal contraction. Crucially, the sum of the stress-free lengths of the left and right main cable elements remains constant, accurately simulating the geometric movement of the boom connection point on the main cable without changing the total length of the main cable.

[0088] Single-span hanger wire breakage simulations were performed on hangers located near the bridge tower, at L / 3, mid-span, and at 2L / 3, with hanger numbers 4#, 23#, 34#, and 55# (the first hanger is taken from the left bridge tower, and the same applies thereafter). Table 1 shows the specific parameters of the hangers in the simulated single-span hanger wire breakage.

[0089]

[0090] Table 1

[0091] By measuring the relative displacement of the corresponding main cable intersection point of each suspender, the following can be obtained: Figure 9 The diagram shows the relative displacement of the main cable intersection point when a single suspender wire breaks.

[0092] Through Table 1 and Figure 9 It can be seen that the trend of the relative displacement of the main cable intersection point is the same when a single suspender wire breaks. Specifically, it can be calculated by finite element software as follows: (1) When the suspender intersection point of No. 4 generates a displacement of 1 mm, the suspender force changes by 2.26t; when the suspender intersection point of No. 23 generates a displacement of 1 mm, the suspender force changes by 2.25t; when the suspender intersection point of No. 34 generates a displacement of 1 mm, the suspender force changes by 2.25t; when the suspender intersection point of No. 55 generates a displacement of 1 mm, the suspender force changes by 2.26t; (2) By comparing the suspender wire breaks at different locations of the suspension bridge, it is found that the change pattern caused by the suspender wire breaks of the entire bridge is the same. The longer the suspender, the greater the relative displacement of the intersection point caused by the suspender wire breaks. The suspender wire breaks at the ...

[0093] The impact of simultaneous wire breakage from multiple suspenders on the deformation of the main cable intersection was verified as follows.

[0094] The study focuses on the simultaneous wire breakage of hangers #4, #13, #23, and #34 in half-spans of the aforementioned bridge (simultaneous wire breakage of multiple hangers is a special case). The wire breakage rates are 20%, 40%, 60%, and 80% respectively. The relative displacement of the main cable intersections across the entire bridge is analyzed, and the results are as follows: Figure 10 As shown.

[0095] When multiple booms break simultaneously, only the relative displacement of the intersection point of the boom and main cable at the break point changes. The trend of this change is almost identical to that of a single boom. The relative displacement at this intersection point and the boom force are studied, and the results are as follows: Figure 4 As shown.

[0096] The trend of multiple broken wires in a single suspender is the same as that of a single broken wire in a suspender; both exhibit an "M"-shaped change at the point of breakage. The simultaneous breakage of multiple wires in a single suspender is a special case. The conclusions are the same as for a single broken wire: for every 1mm relative displacement at the main cable intersection, the suspender force changes by approximately 2.25t, with a sensitivity of about 1.7%. Furthermore, the displacement at the intersection of the damaged suspenders shows a significant downward abrupt change.

[0097] Analysis of broken wires in single and multiple suspenders demonstrates that using the relative displacement of the main cable intersection point to detect suspenders is sufficiently reliable.

[0098] The impact of a single suspender anchor loosening on the deformation of the main cable intersection was verified as follows.

[0099] If the anchor of the suspender detaches, the suspender will extend freely, resulting in an increase in the length of the stress-free cable. By adjusting the stress-free length of the suspender, the change in suspender force can be controlled in reverse. The change in suspender force will cause a change in the relative displacement of the main cable intersection, thus obtaining the change in the relative displacement of the main cable intersection when a single suspender anchor detaches. The specific parameters of the suspender are shown in Table 2.

[0100]

[0101] Table 2

[0102] The stress-free length of a boom refers to its length in its free state when it is not subjected to any load.

[0103] In the finite element model, the first element can be determined after form finding. The length of the No. 1 hanger unit is defined as... And assume it to be the first The length of the stressed cable of the No. 1 hanger is given. The elongation of the hanger under the combined weight of its own weight and the main beam is then calculated as follows: The elongation produced by the boom itself is The length of the stress-free cable of the suspension rod is:

[0104] (1),

[0105] In formula (1), —The length of the stress-free cable of the boom, —Lifting rod force, —Linear density of the boom, — Elastic modulus of the hanger, A — Cross-sectional area of ​​the hanger.

[0106] In this embodiment, the form-finding process specifically includes initial model establishment: establishing the bridge towers, main beams, and simplified "triangular" main cables; defining element types. The aim is to create the basic geometric model for form-finding calculations. Boundary and load settings: consolidating the tower bases and anchorages; applying all constant loads (self-weight, secondary dead load). The aim is to define the "zero-load" load case for the entire bridge structure. Iterative solution: cyclically executing "nonlinear analysis → obtaining displacement deviation → updating node coordinates." The aim is to solve for the unique horizontal force G of the main cable that satisfies the design alignment under dead load. Determining the completed bridge state: converting the suspender forces into stress-free cable lengths or initial tension forces and applying them to the model. The aim is to establish an accurate "completed bridge model" that can be used for subsequent analysis.

[0107] This invention simulates anchor loosening by adjusting the stress-free cable length of the boom. In reality, anchor loosening causes the boom force to gradually decrease until it completely falls off. Therefore, in simulating anchor loosening, the change in stress-free cable length can be increased to a certain extent based on its design length. Thus, the stress-free cable lengths of booms #4, #23, #34, and #55 are increased, and the difference between the boom length and its stress-free cable length is taken as the increment. The increments are increased by 50%, 100%, 150%, and 200% for the four booms, respectively. The analysis results are as follows. Figure 11 As shown.

[0108] When a single anchor comes loose, the relative displacement change trend of the main cable intersection is the same as that of the broken wire of the suspender. The deformation of the intersection of the damaged suspender is also an "M" shaped change. The following can be obtained by finite element software calculation: (1) When the intersection of suspender #4 produces a displacement of 1mm, the suspender force changes by 2.26t; when the intersection of suspender #23 produces a displacement of 1mm, the suspender force changes by 2.26t; when the intersection of suspender #34 produces a displacement of 1mm, the suspender force changes by 2.25t; when the intersection of suspender #55 produces a displacement of 1mm, the suspender force changes by 2.26t, which is exactly the same as the change caused by the damage of the suspender; (2) By comparing the anchors at different locations of the suspension bridge where the anchors are loose, it is found that the change pattern caused by the damage of the suspenders of the whole bridge is the same. The longer the suspender, the greater the relative displacement of the intersection. The displacement caused by the damaged suspender is the largest, affecting the two adjacent suspenders.

[0109] Comparing the effects of broken shunt wires and loose anchors reveals that the relative displacement changes at the main cable intersection follow identical patterns. Shunt damage caused by broken shunt wires results in a decrease in shunt force due to a reduction in the shunt's cross-sectional area, while shunt damage caused by loose anchors results in a decrease in shunt force due to an increase in the length of the stress-free cable. Both ultimately reduce the shunt's force. Therefore, the resulting patterns are almost identical; in both types of damage, the deformation at the main cable intersection exhibits an "M"-shaped change.

[0110] The impact of multiple suspender anchor loosening on the deformation of the main cable intersection was verified as follows.

[0111] The study focuses on the simultaneous anchorage detachment of hangers #4, #13, #23, and #34 in half-spans of the aforementioned bridge (simultaneous anchorage detachment of multiple hangers is a special case). The damage rates are 50%, 100%, 150%, and 200%, respectively. The relative displacement of the main cable intersections across the entire bridge is also analyzed, and the results are as follows: Figure 12 As shown.

[0112] When multiple suspenders simultaneously lose their anchorages, only the relative displacement of the intersection point of the main cable and the damaged suspender changes, affecting the adjacent two suspenders. The trend of this change is almost identical to that of a single suspender anchorage loosening. To provide a more intuitive comparison, the relative displacement of the intersection point and the change in suspender force were studied. The results are as follows: Figure 6 As shown.

[0113] When cable clamp slippage occurs, the change in relative displacement at the main cable intersection point is a sudden upward shift of the suspender at the damaged location, and the lines in the graph of the relative displacement change at the main cable intersection point show multiple W-shapes. During slippage, the main cable on the left side of the cable clamp extends and the main cable on the right side shortens, changing the suspender force. At the same time, the slippage of the cable clamp causes lateral displacement at the suspender intersection point. Therefore, the changes in cable clamp slippage are different from those in cases of suspender wire breakage or anchor loosening.

[0114] The effect of slippage of a single cable clamp on the deformation of the main cable intersection is verified as follows.

[0115] The slippage of the cable clamps is simulated by applying unit temperature to the main cable unit (a main cable unit usually refers to the section of the main cable connecting two adjacent suspender cable clamps. The entire main cable is represented in the model as a chain composed of these units connected end to end). The cable clamp slippage effect is achieved by applying unit temperature to the main cable unit (a main cable unit usually refers to the section of the main cable connecting two adjacent suspender cable clamps under the effect of thermal expansion and contraction, the left side expands when heated and the right side contracts when cooled, but the sum of the stress-free lengths of the two main cable sections remains unchanged). Table 3 shows the specific parameters of the suspender, and Table 4 shows the temperature rise and fall and the change in the stress-free cable length of the main cable.

[0116]

[0117] Table 3

[0118]

[0119] Table 4

[0120] The results show that when the same unit temperature is applied to the units on both sides of the main cable intersection, the displacement changes on the left and right sides are not completely consistent. Specifically, for hanger No. 3, the left side elongates by 1.5308 mm for every 10-degree increase in temperature, while the right side elongates by 1.525 mm for every 10-degree decrease in temperature; for hanger No. 13, the left side elongates by 1.803 mm for every 10-degree increase in temperature, while the right side elongates by 1.4763 mm for every 10-degree decrease in temperature; and for hanger No. 23, the left side elongates by 1.4487 mm for every 10-degree increase in temperature, while the right side elongates by 1.467 mm for every 10-degree decrease in temperature. The calculation error is approximately 0.0001 mm.

[0121] Because the relative displacement of the main cable intersection point is different when the left and right sides are heated to the same temperature, different unit temperatures need to be applied to the main cables on the left and right sides of the suspender to ensure that the elongation of the left main cable equals the shortening of the right main cable, thus maintaining the sum of the stress-free cable lengths of the two main cables constant. Suspension rods #3, #13, and #23 were used, and their cable clamps were allowed to slip by 5mm, 10mm, 15mm, and 20mm respectively. The results are as follows... Figure 13 As shown.

[0122] The results show that when cable clamp slippage occurs, the change in relative displacement at the main cable intersection point is due to a sudden upward change in the suspender at the damaged location, and the line in the graph of the relative displacement change at the main cable intersection point only shows a W shape. During slippage, the main cable on the left side of the cable clamp elongates and the main cable on the right side shortens, the suspender force changes, and at the same time, the slippage of the cable clamp causes a lateral displacement at the suspender intersection point. Therefore, the changes in cable clamp slippage are different from those in cases of suspender wire breakage or anchor loosening.

[0123] The impact of slippage of multiple cable clamps on the deformation of the main cable intersection point was verified as follows.

[0124] This invention involves simultaneously sliding three suspenders by cable clamping at intervals of 5mm, 10mm, 15mm, and 20mm, and then analyzing the relative displacement of the main cable intersection points across the entire bridge. The results are as follows: Figure 14 As shown, when multiple cable clamps slip, only the relative displacement of the intersection point of the main cable and the suspender at the slipped cable clamp changes, and its trend is almost the same as that of a single cable clamp slip.

[0125] Explanation: In this solution, the auxiliary cable is pre-tensioned to ensure it remains straight. The displacement sensor includes a magnetic ring. As the object being measured moves, the magnetic ring's magnetic field interacts with the annular magnetic field within the waveguide of the displacement sensor, triggering a magnetostrictive effect. The movement of the magnetic ring directly reflects the displacement of the object being measured.

[0126] This embodiment also discloses a measurement system for measuring the relative displacement of the intersection of the main cables of a suspension bridge, including multiple first connecting components, multiple displacement sensors and multiple auxiliary cables, as well as a control module and an alarm.

[0127] like Figure 22 As shown, the displacement sensor is used to monitor the displacement between the main cable intersection and the auxiliary cable, such as... Figure 15 , 16 As shown, the displacement sensor includes a displacement sensor magnetic ring 101, a displacement sensor measuring rod 102, and a displacement sensor electronic compartment 103. The displacement sensor measuring rod 102 and the displacement sensor electronic compartment 103 are connected, and the displacement sensor magnetic ring 101 is fitted onto the displacement sensor measuring rod 102.

[0128] The displacement sensor magnetic ring 101 is provided with a second connecting assembly for connecting the magnetic ring to the auxiliary cable. The second connecting assembly includes a second connecting member sleeved on the displacement sensor magnetic ring 101, and a plurality of connecting rings 301 that can slide and cooperate with the second connecting member. The second connecting member includes a connecting cylinder 302 and two symmetrically arranged connecting posts 303. The connecting cylinder 302 is sleeved on the displacement sensor magnetic ring 101, and the two connecting posts 303 are respectively connected to the connecting cylinder 302. Figure 17 , 19 As shown, the lower end face of the connecting post 303 is provided with a placement groove 304, and the placement groove 304 is provided with a connecting rod 305 along the length direction of the connecting post 303. The connecting ring 301 is slidably engaged with the connecting rod 305. The connecting ring 301 is elastic and has a notch at its lower end, which can be used to engage with the auxiliary cable.

[0129] In this embodiment, there are four connecting rings 301. Two connecting rings 301 are provided on each connecting rod 305. A connecting ring is provided at the sliding engagement point between the connecting ring 301 and the connecting rod 305, and the connecting ring 301 slides with the connecting rod 305 through the connecting ring.

[0130] The magnetic ring can be connected to two connecting posts 303 via the connecting cylinder 302. The connecting ring 301 allows the magnetic ring to be indirectly and always connected to the auxiliary cable, so that the magnetic ring can monitor the displacement between the auxiliary cable and the cable clamp. The setting of the connecting rod 305 and multiple connecting rings 301 can flexibly adjust the position and number of connecting rings 301 according to the requirements. For example, for rods No. 1, No. 2, and No. 3, there are two auxiliary cables connected between rods No. 1 and No. 3, and two connecting rings 301 can be selected.

[0131] Furthermore, since the first support column 206 is located between the two second connecting plates 203, it not only enhances the connection strength between the second connecting plate 203 and the first connecting plate 201, but also allows the two connecting columns 303 to be symmetrically arranged, with the magnetic ring in the middle and the two connecting columns 303 on either side of the magnetic ring. Because the two second connecting plates 203 are located on either side of the first support column 206, the two auxiliary cables connecting booms 1 and 3 are also located on either side of the magnetic ring. The magnetic ring is connected to the corresponding auxiliary cables via connecting rings 301 on both sides. Compared to a magnetic ring located outside the two auxiliary cables (i.e., the two auxiliary cables are on the same side of the magnetic ring), the magnetic ring's trajectory is more susceptible to uneven tension distribution in the auxiliary cables. For example, if booms 1 and 3 are subjected to asymmetrical forces, the auxiliary cables may experience lateral shift or torsion, resulting in an eccentricity between the center of the magnetic ring and the theoretical displacement axis (such as the boom axis). This eccentricity introduces an additional lateral displacement component, causing the "total displacement" measured by the displacement sensor to contain spurious errors. In this invention, the magnetic ring is located between two auxiliary cables. When the boom or auxiliary cables deform, the magnetic ring is balanced by the tension on both sides and is more likely to move along the theoretical displacement axis (such as the axial direction). The eccentricity error is significantly reduced and the measured value is closer to the true displacement.

[0132] The first connecting component is connected to the suspension bridge cable clamp. The first connecting component is used to place the displacement sensor and keep the displacement sensor in a vertical position at all times, and to provide connection points for the auxiliary cable.

[0133] like Figure 15 As shown, the first connecting assembly includes a first connecting plate 201, a limiting assembly, two first connectors for providing connection points for the auxiliary cable, and a first support for placing a displacement sensor.

[0134] The first connecting plate 201 is provided with a plurality of first connecting holes 202. The number of first connecting holes 202 is the same as the number of bolts on one side of the cable clamp (the cable clamp has two bolt connecting planes, which are located on both sides of the main cable respectively, and the first connecting plate 201 is located on one of the bolt connecting planes). The first connecting plate 201 is fitted onto the cable clamp bolts through the first connecting holes 202 and is connected to the cable clamp bolts.

[0135] like Figure 15 As shown, the first connector includes a second connecting plate 203 and a first support plate 204 that are perpendicular to each other and connected. Both the second connecting plate 203 and the first support plate 204 are connected to the first connecting plate 201. The second connecting plate 203 is located on the center line of the bolt connection plane of the cable clamp along the length direction (the second connecting plate 203 is located on the center line of the length direction of the first connecting plate 201). The second connecting plate 203 is provided with a second connecting hole 205, and the second connecting plate 203 is connected to the auxiliary cable through the second connecting hole 205.

[0136] In this embodiment, the inner wall of the second connecting hole 205 near the upper end of the second connecting plate 203 is wavy, and the second connecting hole 205 can be used to connect two auxiliary cables. Specifically, the wavy shape can be a heart-shaped upper half, or it can be a series of outwardly convex arc segments, an inwardly concave arc segment, and an outwardly convex arc segment connected in sequence, with the inwardly concave arc segment being shorter.

[0137] The inner wall of the second connecting hole 205 near the upper end of the second connecting plate 203 is wavy, meaning it bulges outward. This allows for limiting the position of the auxiliary cable when it connects to the second connecting plate 203. It also allows for selection of the number of auxiliary cables to be installed, such as 1, 2, and 3 suspenders. If the suspension bridge is located in a harsh environment (e.g., strong winds), two auxiliary cables can be connected between suspenders 1 and 3 to improve monitoring accuracy. If the suspension bridge is located in a favorable environment, one auxiliary cable can be connected between suspenders 1 and 3. According to this invention, a single auxiliary cable can also be stably installed. Depending on the age of the suspension bridge, for example, if the suspension bridge is old, two auxiliary cables can be connected between suspenders 1 and 3. The auxiliary cables, two parallel cables, construct a stable reference plane in space. Compared to a linear reference formed by a single cable, it has a stronger ability to resist lateral disturbances such as wind-induced vibration, providing a more stable reference for measurement. The displacement sensor magnetic ring 101 is symmetrically connected between the two auxiliary cables through connectors, forming a balanced force structure. When the system is under force, this structure can effectively suppress the torsion and lateral displacement of the magnetic ring, ensuring that its movement trajectory is strictly along the vertical measurement axis, thereby eliminating eccentricity error. The dual-cable configuration provides hardware redundancy, enhances the long-term operational reliability and risk resistance of the monitoring system in harsh environments, ensures the continuity of monitoring data, and improves monitoring accuracy.

[0138] In this embodiment, the first support plate 204 is an isosceles trapezoid, and the first support plate 204 can increase the connection strength between the second connecting plate 203 and the first connecting plate 201.

[0139] like Figure 15 , 18 As shown, the first support member includes a first support column 206 connected to the first connecting plate 201, a universal joint 207, a second support column 208, a connecting plate 209, and a first nut 212. The first support column 206 is located between the two second connecting plates 203 and is connected to the corresponding second connecting plates 203 respectively. The diameter of the first support column 206 is larger than the width of the second connecting plate 203. The center of the first support column 206 is located on the center line of the length direction of the first connecting plate 201. The first support column 206 and the second support column 208 are connected by the universal joint 207. The displacement sensor is detachably connected to the second support column 208 through the connecting plate 209.

[0140] The first support column 206 can rotate in the vertical plane via the universal joint 207.

[0141] The first support column 206 is connected to the two first connecting plates 201, which allows for the installation of the universal joint 207 and the second support column 208. This enables the displacement sensor and the auxiliary cable to be located on a single first connecting assembly, and also ensures that the displacement sensor is located on the centerline of the cable clamp's length direction. This minimizes system errors and interference factors, making the measured value closer to the true displacement and thus improving monitoring accuracy. For example, if the sensor deviates from the centerline, its measurement point will be at a distance (eccentricity) from the actual deformation center of the cable clamp. When the cable clamp twists or bends, the eccentricity will cause the sensor measurement value to include additional "false displacement" (such as the lateral component caused by twisting), rather than pure axial or target direction displacement. When located on the centerline, the sensor measurement point coincides with the deformation center of the cable clamp. Geometric symmetry minimizes the influence of twisting or bending on the measured value, ensuring that the measured value only reflects the displacement in the target direction, thereby reducing system errors. For example, when the cable clamp is under stress (such as cable tension, wind vibration, etc.), its internal stress distribution is usually symmetrical about the centerline. If the sensor deviates from the centerline, it may be located in a stress concentration area (such as an edge or corner), causing the measured value to be affected by local stress fluctuations rather than overall deformation. The stress distribution is more uniform at the centerline, and the sensor measurement value can better reflect the overall deformation trend of the cable clamp rather than local anomalies, thus improving data reliability.

[0142] The diameter of the first support column 206 is larger than the width of the second connecting plate 203. The first support column 206 is also connected to the first connecting plate 201. Compared with the second connecting plate 203, the contact area between the first support column 206 and the first connecting plate 201 is increased. The first support column 206 can also enhance the connection strength between the second connecting plate 203 and the first connecting plate 201.

[0143] Since the main cable of the suspension bridge is curved, and all displacement sensors need to be kept perpendicular to the horizontal plane, that is, perpendicular to the bridge deck (assuming the bridge deck is parallel), the first support column 206 and the second support column 208 are connected by a universal joint 207, which allows the displacement sensor at any position on the main cable to be kept perpendicular to the horizontal plane. The displacement sensor is detachably connected to the second support column 208 through the connecting plate 209, which facilitates the replacement of the displacement sensor.

[0144] like Figure 15 , 18 As shown, the second support column 208 is provided with a through hole 210 for placing a displacement sensor. The second support column 208 and the connecting plate 209 are bolted together. The connecting plate 209 is provided with a strip hole 211. One end of the displacement sensor measuring rod 102 passes through the strip hole 211. The displacement sensor measuring rod 102 is connected to the first nut 212. The first nut 212 abuts against the upper surface of the connecting plate 209.

[0145] The through hole 210 can be used to house the displacement sensor electronic compartment 103, and also serves to shield the displacement sensor electronic compartment 103 from rainwater, protecting the equipment performance and extending its service life. It can also provide a through channel for the displacement sensor cable. With the addition of the universal joint 207, the through hole 210 allows the displacement sensor cable to be smoothly connected to the displacement sensor, and also allows the displacement sensor to rotate within a 180° range in the plane as needed, ensuring that the displacement sensor is always perpendicular to the horizontal plane. The connection plate 209, the first nut 212, the displacement sensor measuring rod 102, the second support column 208, the strip hole 211, and the through hole 210 work together to ensure that the displacement sensor is stably located within the second support column 208.

[0146] The limiting assembly includes two opposing limiting elements, one for limiting and the other for providing support, such as... Figure 20 , 21 As shown, the limiting component includes a first limiting post 401, a second limiting post 402, and a spring 403. The first limiting post 401 is connected to the side of the first connecting plate 201. The inner side of the first limiting post 401 is provided with a first receiving groove 404 for accommodating the second limiting post 402. The lower surface of the first connecting plate 201 is provided with a second receiving groove 405, one end of which is connected to the side of the first connecting plate 201. The second receiving groove 405 is arranged along the length direction of the first connecting plate 201. One end of the spring 403 is connected to the inner wall of the second receiving groove 405, and the other end is connected to the second limiting post 402. The upper end of the second limiting post 402 abuts against the inner wall of the second receiving groove 405. The second limiting post 402 can be located inside the first limiting post 401 through the first receiving groove 404.

[0147] Depending on the requirements, the measurement system can be installed during the construction of the suspension bridge or after the suspension bridge is built. This invention can be applied to different scenarios as needed, ensuring that the first connecting component is always stably connected to the cable clamp. For example, when constructing a suspension bridge, the first connecting component is connected to the cable clamp before connecting the second nut to the bolt on the cable clamp. At this time, the first connecting plate 201 can fit against the bolt connection plane of the cable clamp. The second limiting post 402 is located inside the first limiting post 401. The cooperation between the second limiting post 402 and the first limiting post 401 on both sides of the first connecting plate 201 can limit the first connecting plate 201 in the length direction of the cable clamp, restrict the lateral displacement of the first connecting plate 201, and prevent the bolts from loosening due to lateral impact or vibration.

[0148] After the suspension bridge is constructed, the second nut is already connected to the bolts on the cable clamp. At this point, when the first connecting assembly is connected to the cable clamp via the bolts, due to the height of the second nut, the first connecting plate 201 on the first connecting assembly fits against the upper surface of the second nut through the first connecting hole 202. However, the remaining part of the first connecting plate 201 is suspended, causing stress concentration in the localized contact area. This means the stress in the contact area is much higher than the average stress, potentially leading to localized deformation or fatigue cracks in the first connecting plate 201. The suspension of the remaining part of the first connecting plate 201 also means that under lateral forces (such as wind vibration or vibration caused by vehicle loads), stress concentration may occur. Under the action of dynamic or bending moment, the suspended area will undergo free deformation, causing the overall stress state of the first connecting plate 201 to deviate from the design expectation. The two second limiting posts 402 can provide support for the first connecting plate 201, disperse the load, reduce stress concentration, prevent the suspended part of the first connecting plate 201 from undergoing free deformation, and extend the service life of the first connecting plate 201. The first limiting post 401 can also limit the first connecting plate 201 in the length direction of the cable clamp, so that the first connecting plate 201 is aligned with the side of the cable clamp, which can limit the lateral displacement of the first connecting plate 201 and prevent the bolts from loosening due to lateral impact or vibration.

[0149] The control module is used to receive and process displacement information monitored by the displacement sensor, and also to control the alarm to open and close.

[0150] The displacement sensor transmits the first displacement information between the main cable intersection and the auxiliary cable, which is detected for the first time, to the control module as the initial displacement. The displacement sensor transmits the second displacement information between the main cable intersection and the auxiliary cable, which is detected, to the control module at a preset frequency. The control module compares the second displacement information with the initial displacement to obtain the relative displacement of the main cable intersection. If the relative displacement of the main cable intersection is greater than a preset threshold, the control module controls the alarm to emit an audible and visual signal.

[0151] In this embodiment, the displacement sensor electronic compartment 103 is located in the through hole 210, the displacement sensor cable is connected to the displacement sensor electronic compartment 103 through the through hole 210, the connecting plate 209 is sleeved on the displacement sensor measuring rod 102 through the strip hole 211, the connecting plate 209 is bolted to the second support column 208, the displacement sensor measuring rod 102 is connected to the first nut 212, and the first nut 212 abuts against the upper surface of the connecting plate 209.

[0152] Repeat the above operation. A corresponding displacement sensor is installed on the first support of all first connecting components. The first connecting plate 201 of the first connecting component is installed on the cable clamp. Specifically, when the second nut is not installed on the cable clamp bolt (that is, when building a suspension bridge), the first connecting plate 201 is sleeved on the cable clamp bolt. The first connecting plate 201 is in contact with the bolt connection plane of the cable clamp. The spring 403 is stretched. The second limiting post 402 is located inside the first limiting post 401. The inner surface of the second limiting post 402 and the inner surface of the first limiting post 401 are in contact with the outer side of the cable clamp. The two limiting components and the cable clamp cooperate to limit the first connecting plate 201. Then, the second nut is connected to the cable clamp bolt to limit the first connecting plate 201 on the bolt connection plane of the cable clamp.

[0153] When the second nut has been installed on the cable clamp bolt (that is, after the suspension bridge is built), the first connecting plate 201 is fitted onto the cable clamp bolt, the second limiting post 402 abuts against the bolt connection plane of the cable clamp, the first limiting post 401 fits against the outer side of the cable clamp, the two second limiting posts 402 cooperate to provide support for the first connecting plate 201, the two first limiting posts 401 and the cable clamp cooperate to limit the first connecting plate 201, and then the first connecting plate 201 is limited on the cable clamp by connecting to the cable clamp bolt through the third nut.

[0154] Repeat the above operation to install the first connecting assembly at the cable clamps where all the hangers of the suspension bridge connect to the main cable, and adjust the position of each displacement sensor through the universal joint 207 so that each displacement sensor is perpendicular to the horizontal plane;

[0155] The cable clamps on both sides of one of the suspension bridge's hangers are connected by an auxiliary cable. The connecting ring 301 on the second connecting assembly is engaged with the auxiliary cable, and the displacement sensor is indirectly connected to the auxiliary cable through the connecting ring 301.

[0156] Repeat the above operation. All cable clamps connecting the suspension bridge's hangers to the main cable are connected to auxiliary cables. Displacement sensors monitor the displacement between the intersection of the auxiliary cables and the main cable at a preset frequency and transmit the monitored displacement information to the control module. The control module uses the first displacement information transmitted by the displacement sensor as the initial displacement and the subsequent displacement information transmitted by the displacement sensor as the second displacement information.

[0157] The control module compares the second displacement information with the first displacement information to obtain the relative displacement of the main cable intersection. If the relative displacement of the main cable intersection is greater than the preset threshold, the control module controls the alarm to emit an audible and visual signal.

[0158] In this embodiment, 1) the present invention monitors the relative displacement of the main cable intersection point by using displacement sensors installed on the cable clamps and auxiliary cables in conjunction with them. This allows for real-time monitoring without the need for periodic bridge closures, enabling timely awareness of the suspender health, timely preventative maintenance, extended bridge lifespan, and reduced lifecycle costs; 2) monitoring does not require closure of the bridge or disruption of traffic; only the unified installation of this measurement system in the early stages is needed, making measurement convenient; 3) the main cable intersection point is the connection between the main cable and the corresponding suspender. However, in practice, the cable clamp is usually chosen as the main cable intersection point. The present invention connects the auxiliary cable and displacement sensor to the cable clamp via a first connecting component, which, compared to the auxiliary cable... When the displacement sensor is connected to the cable clamp separately, it allows both the auxiliary cable and the displacement sensor to be located at the same point on the cable clamp, such as on the centerline of the cable clamp's length direction. This means the connection point between the auxiliary cable and the cable clamp is on the centerline of the cable clamp's length direction, and the connection point between the displacement sensor and the cable clamp is also on the centerline of the length direction. This ensures that the auxiliary cable connects to the main cable intersection point (which can be a point on the centerline of the cable clamp's length direction) and another main cable intersection point as initially designed, rather than deviating from the centerline of the cable clamp and being closer to the side of the cable clamp, thus improving monitoring accuracy. When the cable clamp is subjected to complex loads, its deformation mode may include not only vertical translation but also torsion and bending. If the sensor is installed off-center, the torsion or bending of the cable clamp will cause the sensor to generate a displacement component in a non-target direction, i.e., a "false displacement." This displacement couples with the true vertical displacement, causing serious interference to the measurement results.By placing the measuring point on the geometric symmetry axis and stress neutral axis of the cable clamp, the influence of bending moment and torque caused by eccentric loading on the measurement can be minimized, allowing the sensor readings to more accurately reflect the pure vertical displacement of the main cable intersection, thereby fundamentally eliminating systematic errors and significantly improving monitoring accuracy; 4) The auxiliary cable and displacement sensor are installed on the first connecting assembly simultaneously. Compared to the auxiliary cable and cable clamp having a separate connector, and the displacement sensor and cable clamp having a separate connector, this method improves monitoring accuracy while reducing installation steps. It only requires one installation, that is, the first connecting assembly is connected to the cable clamp, without multiple connectors being connected to the cable clamp separately; 5) By cooperating with multiple auxiliary cables, multiple displacement sensors, and multiple first connecting assemblies, the relative displacement of the main cable intersection can be monitored synchronously, that is, the deformation of the suspender can be monitored. Simultaneous monitoring at multiple monitoring points can also obtain a relative displacement change diagram of the corresponding main cable intersection point of each suspender. That is, based on the relative displacement of each main cable intersection point of the suspension bridge, a diagram of the relative displacement change of the main cable intersection point is obtained with the suspender number on the horizontal axis and the relative displacement on the vertical axis, so as to further determine the damage type of the corresponding damaged suspender; 6) Since the relative displacement change of the main cable intersection point is small, a few centimeters or millimeters, if displacement sensors are directly installed on the main cable intersection point to directly monitor the change in distance between the main cable intersection point and the ground, the measurement accuracy cannot meet the requirements. However, this invention connects the two ends of the auxiliary cable to the two main cable intersection points respectively, and uses the rigidity of the auxiliary cable to transmit the displacement. The displacement sensor monitors the relative displacement between the main cable intersection point and the auxiliary cable above the main cable intersection point, which is equivalent to converting the tiny absolute displacement into relative displacement for measurement, which can amplify the displacement change and thus improve the measurement accuracy.

[0159] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A method for identifying and locating damage to suspension bridge hangers based on main cable morphological variations, characterized in that: Includes the following steps: S1: Obtain the center point of the line connecting the intersection points of the main cables on both sides of one of the suspension bridge's suspenders by passing through the intersection points of the main cables on both sides of the suspender. S2: The intersection of the main cables of the suspension bridge's suspender. The initial displacement of the main cable intersection point of the suspender is obtained by measuring the difference between the actual position at a given time and the height of the center point. This displacement is then measured across the suspension bridge. The difference between the actual position and the center point height at a given time point yields the deformation displacement at the intersection of the main cable of the suspender. The difference between the deformation displacement and the initial displacement is the relative displacement. S3: Repeat S1-S2 to obtain the relative displacement of the main cable intersection point of each suspender of the suspension bridge, and obtain the relative displacement change diagram of the main cable intersection point with the suspender number on the horizontal axis and the relative displacement on the vertical axis based on the relative displacement of each main cable intersection point of the suspension bridge. S4: When the line in the relative displacement change graph of the main cable intersection point is M-shaped, the damage to the suspender is vertical. The horizontal coordinate of the inward bend in the M-shaped line is the corresponding damaged suspender. When the line in the relative displacement change graph of the main cable intersection point is W-shaped, the damage to the suspender is lateral damage. The horizontal coordinate of the outward bend in the W-shaped line is the corresponding damaged suspender.

2. The method for identifying and locating suspension bridge hanger damage based on main cable morphological variations according to claim 1, characterized in that: When the line in the diagram showing the relative displacement change of the main cable intersection is M-shaped, vertical damage includes broken wires in the suspender or loosening of the anchor.

3. The method for identifying and locating suspension bridge hanger damage based on main cable morphological variations according to claim 1, characterized in that: When the line in the diagram of relative displacement change at the main cable intersection is W-shaped, lateral damage includes cable clamp slippage.

4. The method for identifying and locating suspension bridge hanger damage based on main cable morphological variations according to claim 2, characterized in that: In S4, if the line in the relative displacement change diagram of the main cable intersection only shows an M shape, the damage to the suspender is a broken wire of a single suspender or a loose anchor of a single suspender. If the lines in the diagram showing the relative displacement of the main cable intersection point appear as multiple M-shapes, the damage to the suspenders is due to multiple broken wires in the suspenders or multiple loose suspender anchors.

5. The method for identifying and locating suspension bridge hanger damage based on main cable morphological variations according to claim 3, characterized in that: In S4, if the line in the relative displacement change graph of the main cable intersection only shows a W shape, the damage to the suspender is the slippage of a single cable clamp; If the lines in the diagram showing the relative displacement of the main cable intersection point appear as multiple W shapes, the damage to the suspender is due to the slippage of multiple cable clamps.

6. The method for identifying and locating suspension bridge hanger damage based on main cable morphological variations according to claim 1, characterized in that: When the line in the diagram of relative displacement of the main cable intersection point is M-shaped, if the difference between the relative displacement of the main cable intersection point of one of the hangers and the relative displacement of the main cable intersection point of the adjacent hanger is less than a preset threshold, then the hanger is a damaged hanger, that is, the inward bending point of the M-shape, as shown in formulas (1) and (2). （1）， （2）， In formulas (1) and (2), For the first The relative displacement of the main cable intersection point of the No. 1 suspender. For the first The relative displacement of the main cable intersection point of the No. 1 suspender. For the first The relative displacement of the main cable intersection point of the No. 1 suspender. This is a preset threshold.

7. The method for identifying and locating suspension bridge hanger damage based on main cable morphological variations according to claim 1, characterized in that: When the line in the diagram of the relative displacement of the main cable intersection point is W-shaped, if the difference between the relative displacement of the main cable intersection point of one of the hangers and the relative displacement of the main cable intersection point of the adjacent hanger is greater than a preset threshold, then the hanger is a damaged hanger, that is, a W-shaped outward bending point, as shown in formulas (3) and (4). （3）， （4）， In formulas (3) and (4), For the first The relative displacement of the main cable intersection point of the No. 1 suspender. For the first The relative displacement of the main cable intersection point of the No. 1 suspender. For the first The relative displacement of the main cable intersection point of the No. 1 suspender. This is a preset threshold.

8. The method for identifying and locating suspension bridge hanger damage based on main cable morphological variations according to claim 1, characterized in that: In S4, half of the initial displacement of the main cable intersection point of the suspender is set as the severe damage threshold. If the absolute value of the relative displacement of the main cable intersection point corresponding to the inward bend point in the M-shape is less than the preset severe damage threshold, then the suspender is partially broken. If the absolute value of the relative displacement of the main cable intersection point corresponding to the inward bend point in the M-shape is greater than the preset severe damage threshold, then the anchor is loose or the suspender is completely broken.

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