Bridge cable steel wire tension estimation method

Abstract

This invention relates to the field of bridge cable technology and provides a method for estimating the tension of steel wires in bridge cables. The method includes analyzing the design frequency, measuring the actual length of the cable, collecting vibration intensity data, filtering effective data segments using a low-pass filter, converting the data, extracting first-order and second-order frequencies, fitting modal curves to verify effectiveness, correcting the design frequency, calculating the relative frequency deviation, average frequency change rate, and mass loss rate, analyzing the equivalent linear density, fitting modal curves, determining the effective length, analyzing the equivalent effective length, analyzing the equivalent frequency, and finally estimating the tension by combining the equivalent linear density, equivalent effective length, and equivalent frequency. This invention effectively ensures the accuracy of bridge cable tension measurement by correcting the influence of corrosion on linear density and by synergistically offsetting deviations using first-order and second-order modal parameters.

Description

Technical Field

[0001] This invention relates to the field of bridge cable technology, specifically a method for estimating the tension of steel wires in bridge cables. Background Technology

[0002] For small suspension bridges in daily life, the cable wires, as the main load-bearing structure supporting the bridge deck, directly determine the structural safety of the entire bridge. During long-term service, the cable wires will corrode due to environmental factors such as high salt and humidity, and air moisture, and will also loosen due to continuous external force vibration, causing the actual tension they bear to gradually fall below the design-expected safe value. Therefore, it is necessary to conduct tension analysis on the cable wires regularly to quantify their actual stress state, determine whether the tension is within the safe range, and ensure the safety of the bridge structure.

[0003] Chinese Patent Publication No. CN101532894B discloses an intelligent portable cable tension measuring instrument. The instrument includes a hydraulic jack for generating the force required to measure cable tension, a bridge arm, a pressure sensor, a displacement sensor, and a microprocessor for measuring cable tension based on the measurement data from the pressure and displacement sensors. The microprocessor includes: a data reading unit for reading the measurement data from the pressure and displacement sensors; a cable diameter estimation unit for estimating the diameter of the cable under test; a cable bending moment estimation unit for obtaining bending moment curves of the cable under test with different cable diameters and deformations as variables using experimental methods, and calculating the bending moment of the cable under test based on the diameter and deformation; and a cable tension measuring unit for calculating the cable tension based on the measurement data from the pressure and displacement sensors, the length of the bridge arm, and the bending moment data of the cable under test. This invention offers a wide measurement range, high measurement accuracy, portability, and a high degree of intelligence.

[0004] When cable wires rust in a corrosive environment, their physical parameters change. These changes directly affect the parameters in the tension measurement process, leading to deviations in the measurement results. Existing technologies often ignore the changes in linear density caused by corrosion when analyzing tension, resulting in uncorrected linear density changes and distorted linear density parameters during estimation.

[0005] In summary, this invention provides a method for estimating the tension of steel wires in bridge cables to solve the above-mentioned problems. Summary of the Invention

[0006] This invention provides a method for estimating the tension of steel wires in bridge cables, which corrects for changes in linear density caused by corrosion, thereby solving the problem of distortion of linear density parameters in the prior art during estimation.

[0007] The specific technical solution of this invention is as follows:

[0008] A method for estimating the tension of steel wires in bridge cables includes the following steps:

[0009] S1. Based on the cable design data, obtain the cable design quality, design linear density, design tension and design length, as well as the cable corrosion calibration data, and analyze the cable design frequency based on the design linear density, design length and design tension.

[0010] This invention targets small suspension bridges with simple structures, ranging in length from 20m to 50m. These bridges typically use a single, thin steel wire rope as the main load-bearing cable, such as a high-strength galvanized steel wire rope. When people walk on these bridges, the main load-bearing cable exhibits significant vibration. In this invention, corrosion calibration data refers to a database of the correspondence between cable corrosion characterization quantities and performance changes, primarily derived from experimental data collected during the cable design phase. This invention mainly selects corrosion calibration coefficients from the corrosion calibration data to quantify the ratio of cable performance changes to the degree of corrosion.

[0011] S2. Measure the actual length of the cable and identify the source of interference;

[0012] In this invention, the actual length of the cable may deviate from the design length due to factors such as installation errors, service deformation, and corrosion damage during actual engineering. Therefore, it is necessary to remeasure the length to reduce the error in subsequent calculations. The interference source refers to factors such as environment, structure, and equipment that may exist in the actual scene and are likely to affect the vibration of the cable.

[0013] S3. Arrange several acceleration sensors along the cable axis to collect the time and acceleration data of the cable, which will be used as the vibration intensity data of the cable.

[0014] In this invention, at least 5-8 acceleration sensors need to be arranged along the cable axis, and they should be evenly arranged to avoid the boundary effect zone of the cable. The acquisition direction of the acceleration sensors is perpendicular to the cable axis.

[0015] S4. Filter the effective data segments in the vibration intensity data, process the effective data segments with low-pass filtering, and convert the processed vibration intensity data into frequency and amplitude data based on the frequency domain analysis method.

[0016] In this invention, filtering effective data segments means removing the initial impact interference and the final attenuation segment, while retaining the effective vibration segment with stable amplitude in the middle; low-pass filtering means removing high-frequency interference such as wind noise and equipment electronic noise, while retaining the useful low-frequency vibration of the cable; frequency domain analysis refers to the fast Fourier transform, which is used to convert the acceleration data in the time domain into frequency amplitude data in the frequency domain.

[0017] S5. Detect peak values ​​in frequency and amplitude data, and analyze the first and second order frequencies of the cable based on modal characteristics;

[0018] In this invention, common tools in the prior art, such as MATLAB, LabVIEW, and HEADAcoustics Artemis, can be used to detect peak values. These tools can automatically identify peak values, i.e., the positions where the amplitude is higher than the surrounding points, after inputting frequency and amplitude data. The first-order frequency is the frequency corresponding to the peak with the lowest frequency and the largest amplitude. The second-order frequency is around twice the first-order frequency. It can be determined by finding a peak value that meets the requirements in the frequency domain data.

[0019] S6. Based on the first-order and second-order frequencies, bandpass filtering is applied to the vibration intensity data. The average amplitude of the filtered data is statistically analyzed to obtain the data pair between the cable axial position and the average amplitude. The data is then fitted into first-order and second-order modal curves. The effectiveness of the first-order and second-order frequencies is verified based on the inherent characteristics of the modal curves.

[0020] In this invention, bandpass filtering refers to retaining the vibration signals of the first and second orders while filtering out interference from other frequencies. Statistical average amplitude is used to obtain the stable amplitude value at each axial position, thus forming a data pair between axial position and average amplitude. For fitting, commonly used tools in existing technologies, such as MATLAB and LabVIEW, are selected. The axial position is used as the horizontal axis data, and the average amplitude as the vertical axis data. After importing into the fitting tool, a half-sine wave model is selected for the first-order mode, and a full sine wave model is selected for the second-order mode. Automatic fitting is then performed to output the first-order and second-order mode curves. The first-order mode curve is a half-sine wave, with amplitudes approximately 0 at both ends and the largest amplitude in the middle. If the fitted curve is high in the middle and low at both ends, and has only one peak, it indicates that the first-order frequency is correct. The second-order mode curve is a sine wave, with amplitudes approximately 0 at both ends, one trough in the middle, and a peak between the ends and the middle. If the fitted curve has one trough and two peaks, conforming to a sine wave, it indicates that the second-order frequency is correct.

[0021] S7. Correct the design frequency according to the actual length. Based on the corrosion calibration data of the cable, analyze the relative deviation between the first-order and second-order frequencies and the corrected design frequency to obtain the mass loss rate of the cable. Based on the mass loss rate and the design mass, analyze the equivalent linear density of the cable.

[0022] In this invention, the design frequency is calculated based on the design length. However, there is a certain error between the design length and the actual length, so the calculation results need to be corrected. The relative deviation refers to the proportion of the difference between the first and second order frequencies of the cable and the corrected design frequency to the corrected design frequency. It is used to quantify the degree of deviation between the actual frequency and the theoretical frequency. The principle is that cable corrosion leads to mass loss, and mass loss directly causes changes in vibration frequency. Specifically, the relative deviation of the single-order frequency is calculated first, and then the average frequency change rate is calculated. The mass loss rate refers to the proportion of the mass lost by the cable due to corrosion, wear, and other factors to the design mass. The higher the mass loss rate, the more severe the corrosion and the more significant the decrease in the cable's load-bearing capacity. The equivalent linear density refers to the actual average mass per unit length of the cable after considering the mass loss rate. It replaces the design linear density for subsequent tension calculations, eliminating the influence of linear density deviation caused by corrosion on tension estimation.

[0023] S8. Fit the shape curves of the first and second modes with sine functions respectively. Based on the intersection points of the fitted first and second curves with the axial coordinate axes, determine the first and second effective lengths. Combine the first and second effective lengths with the frequency to analyze the equivalent effective lengths of the first and second modes.

[0024] In this invention, the first-order and second-order modal shape curves are approximate modal curves. By fitting them with sine functions, the approximate modal curves can be corrected into standard sine functions, thereby establishing a standard model that can be mathematically solved. According to the theory of string vibration, the intersection of the fitted curve with the axial coordinate axis is essentially the node position of the cable vibration, and the effective length is precisely the distance between the nodes of the cable that actually participate in the vibration. The equivalent effective length is the optimal comprehensive value obtained by combining the first-order and second-order effective lengths with the frequency, with the aim of balancing the deviations of different modes.

[0025] S9. Analyze the equivalent frequency of the cable based on the first-order and second-order frequencies.

[0026] In this invention, the equivalent frequency is designed by weighting the fourth and third powers, prioritizing the second-order frequency with higher modal stability, while retaining the basic vibration information of the first-order frequency, and using the stability of the second order to offset the susceptibility of the first order to interference.

[0027] S10. Based on the cable's equivalent linear density, equivalent effective length, and equivalent frequency, analyze the estimated tension of the cable.

[0028] In this invention, the tension is estimated by replacing the ideal design parameters with corrected actual parameters based on the theory of string vibration, thereby eliminating the interference of multi-source errors on the tension.

[0029] In a preferred embodiment, in step S1, the design frequency of the cable is analyzed based on the following formula:

[0030]

[0031] In the formula, This represents the nth design frequency; n represents the modal order. Indicates the design length of the cable; Indicates the design tension of the cable; This indicates the design linear density of the cable.

[0032] In a preferred embodiment, in step S5, the modal characteristics are related to the frequency order in string vibration theory, expressed by the following formula:

[0033]

[0034] In the formula, It represents the first-order frequency.

[0035] In a preferred embodiment, in step S7, the design frequency is corrected based on the following formula:

[0036]

[0037] In the formula, This represents the nth-order design frequency after correction; This indicates the actual length of the cable.

[0038] In a preferred embodiment, in step S7, the cable mass loss rate is analyzed based on the following formula:

[0039]

[0040] In the formula, This represents the relative deviation between the nth-order frequency and the corrected design frequency; the rate of change of the nth-order frequency of the cable is... ;

[0041]

[0042] In the formula, This indicates the cable's mass loss rate; This represents the corrosion calibration coefficient obtained from the corrosion calibration data of the cable; This represents the average frequency change rate of the cable.

[0043] In this invention, the corrosion calibration coefficient is a proportionality coefficient determined experimentally during the cable design phase. It is used to describe the quantitative relationship between the cable's frequency change rate and mass loss rate. Furthermore, for cables lacking corrosion calibration data, data can be obtained through accelerated corrosion experiments. Specifically, steel wire samples of the same material and specifications as the cable can be selected and subjected to salt spray tests, electrochemical corrosion, etc., to induce different degrees of corrosion in the samples. The mass loss rate at each corrosion stage is measured, and vibration tests are performed on the samples at each corrosion stage to obtain the first and second order frequencies. The relative deviations from the frequencies when the cables are not corroded are calculated, and the mass loss rate is then fitted to the relative frequency deviation to obtain the proportional relationship between the two, i.e., the corrosion calibration coefficient.

[0044] In this invention, the average frequency change rate refers to the arithmetic mean of the relative deviations of the first-order frequency and the second-order frequency of the cable. It is used to integrate the change information of the two-order frequencies, reduce the error interference of the single-order frequency, and make the frequency change rate more reflective of the overall quality loss of the cable.

[0045] In a preferred embodiment, in step S7, the equivalent linear density of the cable is analyzed based on the following formula:

[0046]

[0047] In the formula, This represents the equivalent linear density of the cable.

[0048] In a preferred embodiment, in step S8, the basic form of the sine function is:

[0049]

[0050] In the formula, This represents the fitted modal displacement of the nth order mode; represents the amplitude coefficient of the nth mode; x represents the axial horizontal coordinate of the cable; The offset parameter represents the nth mode; This represents the effective length of the nth mode.

[0051] In this invention, the lateral vibration of the cable follows the theory of string vibration, and the analytical solution of the partial differential equation is in the form of a sine function. Since the cable has problems such as non-ideal boundary and length deviation, the effective length is used to replace the design length, the offset parameter is used to correct the boundary offset, and the amplitude coefficient is used to adapt the vibration intensity.

[0052] In a preferred embodiment, in step S8, the equivalent effective length of the cable is analyzed based on the following formula:

[0053]

[0054] In the formula, Indicates the equivalent effective length; Indicates the effective length of the p-th mode; This represents the effective length of the q-th mode; p and q represent the mode order, with p taking the value 1 and q taking the value 2. This represents the frequency of the p-th mode; This represents the frequency of the q-th mode.

[0055] In this invention, the effective length of a single-order mode has a mode-specific error, and direct use can easily lead to serious distortion in tension estimation. It is necessary to compensate for the deviation by integrating multi-order data.

[0056] In a preferred embodiment, in step S9, the equivalent frequency of the cable is analyzed based on the following formula:

[0057]

[0058] In the formula, This indicates the equivalent frequency of the cable.

[0059] In this invention, the second-order frequency of the ideal string vibration is twice that of the first-order frequency. However, in actual cables, deviations may occur due to corrosion, boundary relaxation, and other reasons. Furthermore, the error sources for the first-order and second-order frequencies are different, so it is necessary to calculate the equivalent frequency to correct the deviation and offset the single-order deviation.

[0060] In a preferred embodiment, step 10 involves estimating the cable tension based on the following formula:

[0061]

[0062] In the formula, This indicates the estimated tension of the cable.

[0063] In this invention, when estimating tension based on string vibration theory, the equivalent linear density is used to eliminate mass loss caused by corrosion, the equivalent effective length is used to eliminate the deviation between the actual vibration length and the design length, the equivalent frequency is used to eliminate measurement errors of single-order frequencies, and the combined effect eliminates the superposition effect of multi-source errors.

[0064] Compared with the prior art, the present invention has the following beneficial effects:

[0065] 1. This invention is based on string vibration theory. It collects the vibration signal of the cable through an accelerometer, filters the effective data segments, eliminates interference by low-pass filtering, fits the first-order and second-order modal curves, and calculates the average frequency change rate by combining the corrosion calibration data of the cable. It then derives the mass loss rate of the cable to obtain the equivalent linear density. This invention solves the problem that the existing technology ignores the influence of corrosion on the linear density, which leads to the overestimation of the tension back-calculation value.

[0066] 2. This invention utilizes the principle of complementary characteristics of different orders of modes to balance the inherent defects of the first-order mode being susceptible to wind noise interference and the second-order mode being overly sensitive to local defects through parameter synergy and fusion, forming a multi-dimensional data cross-validation mechanism, which solves the problem of low tension estimation accuracy of single-order modes. Attached Figure Description

[0067] Figure 1 This is a schematic diagram of the overall process of the present invention.

[0068] Figure 2 This is a schematic diagram showing the change of the first-order frequency of cables with different tensions as a function of the number of days of corrosion.

[0069] Figure 3 This is a schematic diagram showing the variation of the second-order frequency of cables under different tensions with the number of days of corrosion. Detailed Implementation

[0070] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0071] Example 1: As Figure 1-3 As shown, this embodiment takes a rural suspension bridge as an example. The main span is 20m and it is used for pedestrians and electric vehicles. The target cable is a 1×7 galvanized steel strand cable that has been in service for 7 years and has yellowish-brown rust on its surface.

[0072] In this embodiment, the cable is designed to be 21m long, with a linear density of 1.18kg / m and a tension of 4.0×10⁻⁶. 5 N, corrosion calibration coefficient is 0.93;

[0073] The design frequency is calculated to be approximately 13.86 Hz for the first order and approximately 27.72 Hz for the second order.

[0074] The cable was measured using a laser rangefinder. Three consecutive measurements were taken during a windless period, and the average value was taken. The actual length of the cable was found to be 21.2m.

[0075] After identifying the sources of interference at the site, the test was conducted in the early morning when there was no wind and no pedestrians.

[0076] Five PCB352C65 accelerometers were selected and placed at 2m, 6m, 11m, 16m and 19m, avoiding the 2m boundary effect zone at both ends. The acquisition direction was perpendicular to the cable axis. Time-acceleration data were collected synchronously through a data acquisition device for 10 seconds.

[0077] Remove the initial 1-second impact segment and the final 2-second decay segment, retaining 7 seconds of stable data to obtain the effective data segment;

[0078] A Butterworth filter is used for low-pass filtering to remove high-frequency noise.

[0079] After performing FFT transformation, the peak amplitude was detected, and the first-order frequency of 14.0 Hz and the second-order frequency of 28.1 Hz were extracted.

[0080] Bandpass filters were set based on first-order and second-order frequencies. The average amplitude at each sensor location was statistically analyzed. First-order mode curves (maximum amplitude of 0.12 mm at the midpoint of 11 m) and second-order mode curves (maximum amplitude of 0.09 mm at 6 m and 16 m) were fitted to confirm the validity of the frequencies.

[0081] Substituting the data, the design frequency is corrected. The corrected first-order design frequency is approximately 13.72 Hz, and the corrected second-order design frequency is approximately 27.44 Hz. The calculated relative deviation of the first-order frequency is approximately 0.0202, and the relative deviation of the second-order frequency is approximately 0.0238. Therefore, the average frequency change rate is approximately 0.022, and the calculated mass loss rate is approximately 2.05%. Substituting the mass loss rate into the calculation, the equivalent linear density is approximately 1.156 kg / m.

[0082] The first-order and second-order modal curves were fitted with sine functions. The first-order curves intersected the coordinate axes at points of 1.9m and 22.6m, yielding an effective first-order length of 20.7m. The second-order curves intersected the coordinate axes at points of 1.7m and 22.6m, yielding an effective second-order length of 20.9m. After combining these equations, the equivalent effective length was calculated to be approximately 20.8m.

[0083] Substituting the first-order and second-order frequencies, the equivalent frequency is calculated to be approximately 13.98 Hz.

[0084] Finally, substituting the equivalent linear density, equivalent effective length, and equivalent frequency into the calculation, the estimated tension is approximately 3.91 × 10⁻⁶. 5 N.

[0085] Example 2: This example is basically the same as Example 1, except that the cable is in a high-humidity area downstream of the bridge for a long time, and the corrosion is more severe. There are reddish-brown rust marks on the surface, and slight rust pits in some areas.

[0086] In this embodiment, a laser rangefinder was used to measure the cable. Three consecutive measurements were taken during a windless period, and the average value was taken. The actual length of the cable was found to be 21.2m.

[0087] After performing FFT transformation, the peak amplitude was detected, and the first-order frequency of 14.41Hz and the second-order frequency of 29.02Hz were extracted.

[0088] Based on the first-order and second-order frequency bandpass filters, the average amplitude at each sensor position was statistically analyzed, and the first-order mode curve (maximum amplitude of 0.15mm at the midpoint of 11m) and the second-order mode curve (maximum amplitude of 0.12mm at positions of 6m and 16m) were fitted to confirm the validity of the frequencies.

[0089] Substituting the data, the design frequency is corrected. The corrected first-order design frequency is approximately 13.72 Hz, and the corrected second-order design frequency is approximately 27.44 Hz. The relative deviation of the first-order frequency is calculated to be approximately 0.05, and the relative deviation of the second-order frequency is approximately 0.0576. Therefore, the average frequency change rate is approximately 0.0538, and the calculated mass loss rate is approximately 5.0%. Substituting the mass loss rate into the calculation, the equivalent linear density is approximately 1.121 kg / m.

[0090] The first-order and second-order modal curves were fitted with sine functions. The first-order curves intersected the coordinate axes at points of 1.9m and 22.5m, yielding an effective first-order length of 20.6m. The second-order curves intersected the coordinate axes at points of 1.8m and 22.5m, yielding an effective second-order length of 20.7m. After combining these equations, the equivalent effective length was calculated to be approximately 20.65m.

[0091] Substituting the first-order and second-order frequencies, the equivalent frequency is approximately 14.38 Hz.

[0092] Finally, substituting the equivalent linear density, equivalent effective length, and equivalent frequency into the calculation, the estimated tension is approximately 3.95 × 10⁻⁶. 5 N.

[0093] The embodiments of the present invention are given for the purposes of illustration and description. Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for estimating the tension of steel wires in bridge cables, characterized in that, Includes the following steps: S1. Based on the cable design data, obtain the cable design quality, design linear density, design tension and design length, as well as the cable corrosion calibration data, and analyze the cable design frequency based on the design linear density, design length and design tension. S2. Measure the actual length of the cable and identify the source of interference; S3. Arrange several acceleration sensors along the cable axis to collect the time and acceleration data of the cable, which will be used as the vibration intensity data of the cable. S4. Filter the effective data segments in the vibration intensity data, process the effective data segments with low-pass filtering, and convert the processed vibration intensity data into frequency and amplitude data based on the frequency domain analysis method. S5. Detect peak values ​​in frequency and amplitude data, and analyze the first and second order frequencies of the cable based on modal characteristics; S6. Based on the first-order and second-order frequencies, bandpass filtering is applied to the vibration intensity data. The average amplitude of the filtered data is statistically analyzed to obtain the data pair between the cable axial position and the average amplitude. The data is then fitted into first-order and second-order modal curves. The effectiveness of the first-order and second-order frequencies is verified based on the inherent characteristics of the modal curves. S7. Correct the design frequency according to the actual length. Based on the corrosion calibration data of the cable, analyze the relative deviation between the first-order and second-order frequencies and the corrected design frequency to obtain the mass loss rate of the cable. Based on the mass loss rate and the design mass, analyze the equivalent linear density of the cable. S8. Fit the shape curves of the first and second modes with sine functions respectively. Based on the intersection points of the fitted first and second curves with the axial coordinate axes, determine the first and second effective lengths. Combine the first and second effective lengths with the frequency to analyze the equivalent effective lengths of the first and second modes. S9. Analyze the equivalent frequency of the cable based on the first-order and second-order frequencies. S10. Based on the cable's equivalent linear density, equivalent effective length, and equivalent frequency, analyze the estimated tension of the cable.

2. The method for estimating the tension of bridge cable wires according to claim 1, characterized in that, In step S1, the design frequency of the cable is analyzed based on the following formula: In the formula, This represents the nth design frequency; n represents the modal order. Indicates the design length of the cable; Indicates the design tension of the cable; This indicates the design linear density of the cable.

3. The method for estimating the tension of bridge cable wires according to claim 2, characterized in that, In step S5, the modal characteristics are related to the frequency order in string vibration theory, expressed by the following formula: In the formula, It represents the first-order frequency.

4. The method for estimating the tension of bridge cable wires according to claim 3, characterized in that, In step S7, the design frequency is corrected based on the following formula: In the formula, This represents the corrected nth-order design frequency; This indicates the actual length of the cable.

5. The method for estimating the tension of bridge cable wires according to claim 4, characterized in that, In step S7, the cable mass loss rate is analyzed based on the following formula: In the formula, This represents the relative deviation between the nth-order frequency and the corrected design frequency; the rate of change of the nth-order frequency of the cable is... ; In the formula, This indicates the cable's mass loss rate; This represents the corrosion calibration coefficient obtained from the corrosion calibration data of the cable; This represents the average frequency change rate of the cable.

6. The method for estimating the tension of bridge cable wires according to claim 5, characterized in that, In step S7, the equivalent linear density of the cable is analyzed based on the following formula: In the formula, This represents the equivalent linear density of the cable.

7. The method for estimating the tension of bridge cable wires according to claim 6, characterized in that, In step S8, the basic form of the sine function is: In the formula, This represents the fitted modal displacement of the nth order mode; represents the amplitude coefficient of the nth mode; x represents the axial horizontal coordinate of the cable; The offset parameter represents the nth mode; This represents the effective length of the nth mode.

8. The method for estimating the tension of bridge cable wires according to claim 7, characterized in that, In step S8, the equivalent effective length of the cable is analyzed based on the following formula: In the formula, Indicates the equivalent effective length; Indicates the effective length of the p-th mode; This represents the effective length of the q-th mode; p and q represent the mode order, with p taking the value 1 and q taking the value 2. This represents the frequency of the p-th mode; This represents the frequency of the q-th mode.

9. The method for estimating the tension of bridge cable wires according to claim 8, characterized in that, In step S9, the equivalent frequency of the cable is analyzed based on the following formula: In the formula, This indicates the equivalent frequency of the cable.

10. The method for estimating the tension of bridge cable wires according to claim 9, characterized in that, In step 10, the estimated tension of the cable is analyzed based on the following formula: In the formula, This indicates the estimated tension of the cable.

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