Method for accurately evaluating bearing capacity of bridge

Abstract

The invention relates to the technical field of bridge bearing capacity evaluation, in particular to a bridge bearing capacity accurate evaluation method, which comprises the following steps: acquiring stress data and deflection data of each position of a bridge under different static loads, and acquiring vibration data of each position of the bridge under the application of a dynamic load; according to the data distribution change and fluctuation degree of each position of the bridge under different static loads, a bridge stress change abnormal value and a bridge deflection data change abnormal value are obtained in combination with nonlinear change characteristics of the data, so that an abnormal coefficient of bridge stress deformation is obtained; the method comprises the following steps: acquiring significant values of abnormal vibration of each position under a dynamic load, further obtaining a comprehensive deviation coefficient of each position under the action of multiple loads, calculating a vulnerability degree value of each position of a bridge, adjusting a grid size in a bridge finite element model construction process, and counting bearing capacity of the bridge under different loads based on the bridge finite element model. The accuracy of the evaluation result of the bridge bearing capacity can be improved.

Description

Technical Field

[0001] This application relates to the field of bridge load-bearing capacity assessment technology, specifically to a precise method for assessing bridge load-bearing capacity. Background Technology

[0002] Bridges bear the weight of numerous vehicles and pedestrians; if a bridge structure has load-bearing capacity issues, serious accidents may occur, endangering public safety. For newly constructed wide-slab hollow slab bridges, accurately assessing their load-bearing capacity is crucial for verifying the quality of bridge design and construction. Wide-slab hollow slab bridges have complex structures and are often subjected to multiple complex loads in actual use. Traditional methods rely on theoretical calculations for load-bearing capacity assessment; however, this method struggles to accurately reflect the impact of local stress concentration, crack propagation, and deformation on the bridge's load-bearing capacity. Failure to fully consider the influence of multiple loads on the bridge's local stress and deformation characteristics leads to inaccurate assessment results that fail to truly reflect the bridge's actual stress state and load-bearing capacity.

[0003] Publication No. CN110672425A discloses a bridge load-bearing capacity testing device and method. This method assesses the bridge's load-bearing capacity by simulating different load conditions and measuring displacement and deformation using a total station under different loading states. However, it fails to adequately consider the influence of local stress concentration, resulting in inaccurate evaluation results. Summary of the Invention

[0004] To address the aforementioned technical problems, this application provides a method for accurately assessing the load-bearing capacity of bridges, thereby resolving the existing issues.

[0005] The method for accurately evaluating the bearing capacity of a bridge according to this application adopts the following technical solution: One embodiment of this application provides a method for accurately assessing the load-bearing capacity of a bridge, comprising the following steps: The stress and deflection data of the bridge at various locations under different static loads were obtained, and the vibration data of the bridge at various locations under applied dynamic loads were also obtained. Based on the stress and deflection data at each location, and considering the distribution and fluctuation of the data at each location of the bridge under different static loads, combined with the nonlinear variation characteristics of the data, abnormal values ​​of stress variation and deflection data variation at each location of the bridge are obtained, and then the abnormal coefficients of stress deformation of the bridge at each location are obtained. Based on the degree of anomaly in the vibration data at various locations of the bridge and the deviation characteristics of the vibration data in the frequency domain, the significant values ​​of vibration anomalies at each location under dynamic load are obtained. The anomaly coefficients are combined to form anomaly characterization vectors at each location of the bridge. The degree of difference between anomaly characterization vectors at different locations is analyzed to obtain the comprehensive deviation coefficient of each location under multiple loads. The average level of the anomaly characterization vectors at each location is combined to obtain the vulnerability value of each location of the bridge. The mesh size in the bridge finite element model construction process is adjusted by the vulnerability value at each location, and the bearing capacity of the bridge under different loads is statistically evaluated based on the constructed bridge finite element model.

[0006] Preferably, the method for calculating the abnormal values ​​of bridge stress changes at each location is as follows: In the formula, D is the abnormal value of bridge stress change at the current location, A is the significance of stress change at the current location, B is the proportion coefficient of nonlinear stress change at the current location, and C is the determination coefficient of the fitted curve corresponding to the stress sequence at the current location. The stress data at each location are arranged in ascending order of static load to obtain the stress sequence at each location, and the fitted curve of the stress sequence is obtained by fitting.

[0007] Preferably, the product of the mean slope of all points on the fitted curve and the range of the stress sequence is used as the significance of the stress change at the current position; the abrupt change points among all slopes are counted, and the largest abrupt change point is used as the dividing point between linear and nonlinear growth of stress data at the current position. The ratio of the number of slopes after the dividing point to the total number of slopes is used as the nonlinear change ratio coefficient of stress at the current position.

[0008] Preferably, the abnormal coefficient of the bridge stress deformation at each location is the average of the abnormal values ​​of the bridge stress change and the abnormal values ​​of the deflection data at each location.

[0009] Preferably, the method for calculating the significance value of the vibration anomaly at each location under dynamic load is as follows: In the formula, H is the significance value of the vibration anomaly at the current position under dynamic load, F is the significance coefficient of the local vibration anomaly at the current position, and G is the difference in natural frequency between the current position and other positions.

[0010] Preferably, all outliers in the vibration data at the current location are extracted, and the absolute value of the difference between each outlier and the mean of all non-outliers is calculated. The sum of all absolute values ​​is used as the local vibration anomaly significance coefficient at the current location.

[0011] Preferably, the spectrum corresponding to the vibration data at the current position is extracted, and the spectral centroid of the spectrum is obtained. The sum of the differences between the frequency corresponding to the spectral centroid at the current position and the frequencies corresponding to the spectral centroids at all other positions is calculated as the difference value of the natural frequency between the current position and other positions.

[0012] Preferably, the comprehensive deviation coefficient of each position under multiple loads is the average distance between the anomaly representation vector of each position and the anomaly representation vectors of all other positions.

[0013] Preferably, the vulnerability value of each location of the bridge is the product of the comprehensive deviation coefficient of each location and the mean value of the data in the anomaly representation vector of each location.

[0014] Preferably, adjusting the mesh size during the bridge finite element model construction process further includes: Normalize all fragility values ​​and set fragility thresholds. If the fragility value is greater than or equal to Then, during the construction of the bridge finite element model, the mesh size of the corresponding geometric region at the corresponding location is reduced to the preset initial mesh size. If the fragility value is less than Then the grid size of the corresponding geometric region at the corresponding position is the preset initial grid size.

[0015] This application has at least the following beneficial effects: This application analyzes in depth the abnormal changes in stress and deflection at various locations of a bridge under static load tests as the load increases, as well as the local vibration anomalies and natural frequency deviations at different locations of the bridge under dynamic load tests. Considering the comprehensive influence of different loads on the bridge's condition, it calculates the vulnerability values ​​corresponding to various locations of the bridge. Its advantage lies in its ability to accurately reflect the local stress and deformation characteristics of the bridge under multiple loads, and to evaluate the bearing capacity using a finite element model. Based on the vulnerability values, the size of the finite element mesh is further optimized, which helps improve the accuracy of the finite element analysis and obtain more precise bearing capacity evaluation results. Attached Figure Description

[0016] To more clearly illustrate the technical solutions and advantages in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A flowchart illustrating the steps of a method for accurately assessing the load-bearing capacity of a bridge, as provided in this application. Detailed Implementation

[0018] To further illustrate the technical means and effects adopted by this application to achieve the intended purpose of the invention, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of a method for accurately assessing the load-bearing capacity of a bridge proposed in this application. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0019] Unless otherwise defined, terms such as “comprising,” “including,” or any other variations thereof are intended to cover a non-exclusive inclusion, such that a circuit structure, article, or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase “comprising one…” does not exclude the presence of other identical elements in the article or device that includes said element. Furthermore, the term “and / or” as used herein includes any and all combinations of one or more of the associated listed items. All technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0020] The following description, in conjunction with the accompanying drawings, details a specific scheme for an accurate assessment method of bridge load-bearing capacity provided in this application.

[0021] This application provides an embodiment of a method for accurately assessing the load-bearing capacity of a bridge. For details, please refer to [link to specific documentation]. Figure 1 This includes the following steps: Step 1: Obtain stress and deflection data at various locations on the bridge under different static loads, and obtain vibration data at various locations on the bridge under applied dynamic loads.

[0022] In practical applications, bridge design must fully consider the maximum load it may bear and its performance under dynamic loads to ensure its safety and reliability. This embodiment uses a combination of static and dynamic load tests to test the load-bearing capacity of a newly constructed wide-span hollow slab bridge. Static load tests simulate the maximum load a bridge may bear in actual use. By applying gradually increasing static loads to the bridge and measuring stress and deflection changes at different locations, it helps to identify potential localized damage and cracks in the bridge structure. Dynamic load tests assess the impact of various dynamic loads on the bridge during actual use, such as vehicle traffic, wind vibration, and earthquakes. By analyzing the vibration frequency and amplitude under dynamic loads, it is possible to analyze whether its dynamic performance meets the requirements.

[0023] In the static load test, this embodiment gradually increases the static load by using a graded loading method. Strain gauges are installed in each geometric region of the bridge to collect stress data, such as at the mid-span, support, and other locations. A total station is used to obtain deflection data at the same locations.

[0024] Thus, stress and deflection data at various locations on the bridge under different static loads are obtained. In the dynamic load test, in this embodiment, a vibrator is used to apply a dynamic load to the bridge, and vibration sensors are used to obtain vibration data at various locations on the bridge under the applied dynamic load, thereby obtaining vibration data at each location under the dynamic load state.

[0025] Step 2: Based on the stress and deflection data at each location, and considering the distribution and fluctuation of the bridge data at each location under different static loads, combined with the nonlinear variation characteristics of the data, the abnormal values ​​of the bridge stress and deflection data at each location are obtained, and then the abnormal coefficients of the bridge stress deformation at each location are obtained.

[0026] By monitoring stress and deflection changes at different locations, we can not only analyze the actual stress state of bridges under different load levels, but also promptly identify potential structural problems, providing a scientific basis for the safe operation and maintenance management of bridges. As the static load increases, the corresponding stress and deflection states at different locations also differ. For example, the mid-span is the part of the bridge where stress and deformation are most concentrated, bearing significant bending stress and deflection deformation. Therefore, the stress and deflection at the mid-span typically increase gradually with increasing load, and the rate of increase is relatively rapid. In contrast, the increase in stress and deflection at some locations is relatively gradual, such as at the supports. This is because the structure at the supports is constrained by the supports, which can better distribute the load, thus mitigating the accumulation of stress and deflection to some extent. Furthermore, when the load reaches a certain value, the stress and deflection data at certain locations may show abrupt changes. Therefore, the characteristics of stress and deflection changes during static load loading are processed as follows.

[0027] First, the stress and deflection data collected at each location are arranged in ascending order of static load to obtain the corresponding stress and deflection sequences. The greater the magnitude or rate of change in stress and deflection, the more prone the corresponding bridge location is to failure.

[0028] In this embodiment, taking the stress sequence at any location as an example, a quadratic polynomial fitting technique is used to obtain the fitting curve of the stress sequence at that location, and then the slope at each point on the fitting curve is calculated. The product of the mean of all slopes and the range of the stress sequence is taken as the stress change significance at that location, where the stress change significance at the current location is denoted as A. The obtained A reflects the stress change amplitude and rate characteristics of the bridge at the current location under static load.

[0029] Furthermore, in the initial stage of static load testing, when the load is small, the stress data usually increases linearly with the increase of the load. However, as the load continues to increase, for example, when the load reaches the yield point of the bridge structure, the rate of increase of the stress data may slow down, resulting in nonlinear growth. If the nonlinear growth stage occurs earlier, that is, the linear growth stage is shortened, it indicates that structural damage occurs earlier at that location, reducing the bridge's load-bearing capacity and increasing the dispersion of the stress data. Based on this characteristic, the linear and nonlinear growth processes are first divided. Since the slopes at each point are relatively consistent during the linear growth process, the corresponding slopes will change abruptly after entering the nonlinear growth stage. Therefore, in this embodiment, the sliding t-test algorithm is used to fit the abrupt change points of all slope data on the curve, and the maximum abrupt change point is taken as the boundary point between linear and nonlinear growth. The ratio of the number of slope data after the boundary point to the total number of all slope data is calculated as the nonlinear change ratio coefficient of stress at that location. The nonlinear change ratio coefficient of stress at the current location is denoted as B. The larger the B is, the earlier the nonlinear growth stage of stress change occurs at the current location, and the larger its proportion.

[0030] Furthermore, the determination coefficient, denoted as C, of ​​the fitted curve corresponding to the stress sequence at each location is calculated. The smaller the C, the greater the dispersion of stress change at that location. Then, based on the significance of stress change and the proportion coefficient of nonlinear change at each location, the anomaly values ​​of bridge stress change at each location are obtained. The specific calculation formula is as follows: In the formula, D is the abnormal value of the bridge stress change at the current location, A is the significance of the stress change at the current location, and B is the proportion coefficient of the nonlinear stress change at the current location. The larger the obtained D is, the greater the amplitude, rate and dispersion of the stress on the bridge at the current location as the load increases, and the earlier the structural damage occurs at that location.

[0031] During static loading, the changes in deflection data and stress data are generally consistent. Therefore, in order to better reflect the bridge condition under different load conditions, the same calculation steps as described above are used for the deflection data at each location. Correspondingly, abnormal values ​​of bridge deflection data at each location are identified.

[0032] Furthermore, combining the variation characteristics of stress and deflection data, the average value of the abnormal values ​​of stress and deflection data at each location is used as the anomaly coefficient of the stress-deformation of the bridge at each location. The anomaly coefficient of the stress-deformation of the bridge at the current location is denoted as E. The obtained E reflects the degree of anomaly of all stresses and deformations at that location under static load.

[0033] Step 3: Based on the degree of anomaly in the vibration data at each location of the bridge and the deviation characteristics of the vibration data in the frequency domain, obtain the significant values ​​of vibration anomalies at each location under dynamic load. Combine the anomaly coefficients to form anomaly characterization vectors at each location of the bridge. Analyze the degree of difference between anomaly characterization vectors at different locations to obtain the comprehensive deviation coefficient of each location under multiple loads. Combine the average level of the anomaly characterization vectors at each location to obtain the vulnerability value of each location of the bridge.

[0034] Furthermore, during dynamic loading, vibration data collected at different locations should exhibit a certain degree of similarity and consistency. If the vibration data at a certain location deviates significantly from those at other locations, it may indicate that localized damage or structural defects are more likely to exist at that location. Specifically, in vulnerable areas, the corresponding vibration data are more prone to showing obvious local anomalies. In addition, under dynamic loading, bridges possess certain natural frequencies. While these frequencies may vary slightly at different locations, they should generally remain consistent. If the natural frequency at a certain location deviates significantly from those at other locations, it similarly indicates that defects are more likely to exist at that location.

[0035] Therefore, taking vibration data at any given location as an example, in this embodiment, the SOS (Stochastic Outlier Selection) detection algorithm is used to obtain all outliers in the vibration data at that location. Then, the mean of the data corresponding to all non-outliers is calculated. The absolute value of the difference between each outlier and the mean is calculated, and the sum of all absolute values ​​is used to characterize the significance coefficient of local anomalies in the vibration data at that location caused by dynamic load. In this embodiment, the sum of all absolute values ​​corresponding to the current location is used as the significance coefficient of local vibration anomalies at the current location, denoted as F. The larger the obtained F, the more obvious the local anomalies in the vibration data at the current location under dynamic load are.

[0036] Simultaneously, in this embodiment, the discrete Fourier transform technique is used to obtain the spectrum of vibration data collected at each location, and the spectral centroid of each spectrum is obtained. The spectral centroid reflects the frequency of the location with the most concentrated energy in the spectrum. Then, the sum of the differences between the frequency corresponding to the spectral centroid at this location and the frequencies corresponding to the spectral centroids at all other locations is calculated as the difference value of the natural frequency between this location and other locations. In this embodiment, the difference value of the natural frequency between the current location and other locations is denoted as G. The larger the G, the more significantly the natural frequency of the bridge at the current location deviates from that of other locations.

[0037] Therefore, the significant value of vibration anomaly at each location under dynamic load is calculated using the following formula: In the formula, H is the significance value of the vibration anomaly at the current position under dynamic load, F is the significance coefficient of the local vibration anomaly at the current position, and G is the difference value of the natural frequency between the current position and other positions. The obtained H reflects the local vibration anomaly and natural frequency deviation characteristics of the bridge at the current position under dynamic load.

[0038] The above steps were used to obtain the changes and state characteristics of relevant parameters at multiple locations of the bridge under static and dynamic loads, which reflect the bridge state under different loads.

[0039] Furthermore, wide-span hollow slab bridges need to possess good static and dynamic load capacity in practical applications. Typically, stress concentration and significant deformation occur in certain critical areas of the bridge, leading to significantly larger abnormal coefficients of bridge stress and deformation at these locations as static load increases, as well as significantly larger values ​​for local vibration anomalies and natural frequency deviations under dynamic load, with marked differences from other locations.

[0040] Therefore, in this embodiment, the abnormal coefficient of the bridge stress deformation at each location and the significant value of the vibration abnormality under dynamic load are combined to form the abnormal characterization vector of each location. Further, preferably, in this embodiment, the mean of the Euclidean distance between the abnormal characterization vector of each location and the corresponding abnormal characterization vector of all other locations is calculated and used as the comprehensive deviation coefficient of that location under multiple loads.

[0041] The comprehensive deviation coefficient reflects the difference in structural damage levels between this location and other locations on the bridge under different loads. Furthermore, the product of the comprehensive deviation coefficient at each location and the mean value of the data in the corresponding anomaly representation vector is used as the vulnerability value for each location on the bridge, reflecting the vulnerability characteristics of the corresponding location under multiple loads.

[0042] Step 4: Adjust the mesh size during the construction of the bridge finite element model by using the vulnerability values ​​at each location, and statistically evaluate the bearing capacity of the bridge under different loads based on the constructed bridge finite element model.

[0043] In this embodiment, by deeply analyzing the abnormal characteristics of stress and deflection at various locations of the bridge under static load test as the load increases, as well as the local vibration anomalies and natural frequency deviation characteristics at different locations of the bridge under dynamic load test, and analyzing the comprehensive influence of different loads on the bridge condition, the vulnerability values ​​corresponding to various locations of the bridge are calculated.

[0044] Furthermore, finite element models of the bridge were constructed using ANSYS software to accurately assess the load-bearing capacity of the hollow slab bridge. Specifically, a higher calculated vulnerability value indicates that the bridge is more prone to deformation and stress concentration at that location. In this case, the mesh size for that region should be reduced during the finite element model construction to obtain more accurate evaluation results. Conversely, a lower calculated vulnerability value allows for a larger mesh size to improve the efficiency of load-bearing capacity assessment.

[0045] Therefore, in this embodiment, a preliminary mesh generation is first performed using the transformation and expansion method to obtain the initial mesh size for each location. Then, the mesh size is optimized based on the vulnerability value. The vulnerability value for all locations is normalized using a minimization-maximization method, and a vulnerability threshold is set. The value is 0.7. If the obtained fragility value is greater than or equal to... Then the size of the mesh in the corresponding geometric region at that location will be reduced to a preset initial mesh size. If the obtained fragility value is less than If the bridge finite element model is constructed using the preset initial mesh size, preferably, in this embodiment the preset initial mesh size is 8mm. In actual application scenarios, the implementer can set it according to the actual situation. This embodiment does not impose any special restrictions on this.

[0046] Furthermore, dynamic load test data is used to dynamically correct the model, resulting in a corrected finite element model that reflects the actual working state of the bridge. Based on this corrected finite element model, the bearing capacity of the bridge under various load combinations is calculated and analyzed using ANSYS software, thereby achieving an accurate assessment of the bridge's bearing capacity. It should be noted that the finite element model construction process using ANSYS software is existing technology and will not be described in detail in this embodiment.

[0047] It is understood that references to "one embodiment" or "some embodiments" in this specification mean that one or more embodiments of this application include the specific features, structures, or characteristics described in connection with that embodiment. Therefore, the appearance of phrases such as "in one embodiment," "in some embodiments," "in other embodiments," or "in still other embodiments" in different parts of this specification does not necessarily refer to the same embodiment, but rather means "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof all mean "including but not limited to," unless otherwise specifically emphasized.

[0048] It should be noted that the order of the embodiments described above is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. Furthermore, the above description focuses on specific embodiments of this specification. Additionally, the processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired results. In some implementations, multitasking and parallel processing are possible or may be advantageous. Moreover, the sequence numbers of the steps in the embodiments do not imply a specific order of execution; the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments in this specification.

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

Claims

1. A method for accurately assessing the load-bearing capacity of bridges, characterized in that, Includes the following steps: The stress and deflection data of the bridge at various locations under different static loads were obtained, and the vibration data of the bridge at various locations under applied dynamic loads were also obtained. Based on the stress and deflection data at each location, and considering the distribution and fluctuation of the data at each location of the bridge under different static loads, combined with the nonlinear variation characteristics of the data, abnormal values ​​of stress variation and deflection data variation at each location of the bridge are obtained, and then the abnormal coefficients of stress deformation of the bridge at each location are obtained. Based on the degree of anomaly in the vibration data at various locations of the bridge and the deviation characteristics of the vibration data in the frequency domain, the significant values ​​of vibration anomalies at each location under dynamic load are obtained. The anomaly coefficients are combined to form anomaly characterization vectors at each location of the bridge. The degree of difference between anomaly characterization vectors at different locations is analyzed to obtain the comprehensive deviation coefficient of each location under multiple loads. The average level of the anomaly characterization vectors at each location is combined to obtain the vulnerability value of each location of the bridge. The mesh size in the bridge finite element model construction process is adjusted by the vulnerability value at each location, and the bearing capacity of the bridge under different loads is statistically evaluated based on the constructed bridge finite element model.

2. The method for accurately assessing the load-bearing capacity of a bridge as described in claim 1, characterized in that, The method for calculating the abnormal values ​​of bridge stress changes at each location is as follows: In the formula, D is the abnormal value of bridge stress change at the current location, A is the significance of stress change at the current location, B is the proportion coefficient of nonlinear stress change at the current location, and C is the determination coefficient of the fitted curve corresponding to the stress sequence at the current location. The stress data at each location are arranged in ascending order of static load to obtain the stress sequence at each location, and the fitted curve of the stress sequence is obtained by fitting.

3. The method for accurately assessing the load-bearing capacity of a bridge as described in claim 2, characterized in that, The product of the mean slope of all points on the fitted curve and the range of the stress sequence is used as the significance of the stress change at the current position. The abrupt change points among all slopes are counted, and the largest abrupt change point is used as the dividing point between linear and nonlinear growth of stress data at the current position. The ratio of the number of slopes after the dividing point to the total number of slopes is used as the nonlinear change ratio coefficient of stress at the current position.

4. The method for accurately assessing the load-bearing capacity of a bridge as described in claim 1, characterized in that, The abnormality coefficient of the bridge stress deformation at each location is the average of the abnormal values ​​of the bridge stress change and the abnormal values ​​of the deflection data at each location.

5. The method for accurately assessing the load-bearing capacity of a bridge as described in claim 1, characterized in that, The method for calculating the significance of vibration anomalies at each location under dynamic load is as follows: In the formula, H is the significance value of the vibration anomaly at the current position under dynamic load, F is the significance coefficient of the local vibration anomaly at the current position, and G is the difference in natural frequency between the current position and other positions.

6. The method for accurately assessing the load-bearing capacity of a bridge as described in claim 5, characterized in that, Extract all outliers from the vibration data at the current location, calculate the absolute value of the difference between each outlier and the mean of all non-outliers, and sum all the absolute values ​​as the local vibration anomaly significance coefficient at the current location.

7. The method for accurately assessing the load-bearing capacity of a bridge as described in claim 5, characterized in that, Extract the spectrum corresponding to the vibration data at the current position, obtain the spectral centroid of the spectrum, calculate the sum of the differences between the frequency corresponding to the spectral centroid at the current position and the frequencies corresponding to the spectral centroids at all other positions, and use this sum as the difference value of the natural frequency between the current position and other positions.

8. The method for accurately assessing the load-bearing capacity of a bridge as described in claim 1, characterized in that, The comprehensive deviation coefficient of each position under multiple loads is the average distance between the anomaly representation vector of each position and the anomaly representation vectors of all other positions.

9. The method for accurately assessing the load-bearing capacity of a bridge as described in claim 1, characterized in that, The vulnerability value at each location of the bridge is the product of the comprehensive deviation coefficient at each location and the mean value of the data in the anomaly representation vector at each location.

10. The method for accurately assessing the load-bearing capacity of a bridge as described in claim 1, characterized in that, The adjustment of mesh size during the construction of the bridge finite element model further includes: Normalize all fragility values ​​and set fragility thresholds. If the fragility value is greater than or equal to Then, during the construction of the bridge finite element model, the mesh size of the corresponding geometric region at the corresponding location is reduced to the preset initial mesh size. If the fragility value is less than Then the grid size of the corresponding geometric region at the corresponding position is the preset initial grid size.

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