A method for precise evaluation of bridge bearing capacity

Abstract

The application relates to the technical field of bridge bearing capacity evaluation, in particular to a precise evaluation method for bridge bearing capacity, which comprises the following steps: stress data and deflection data of each position of a bridge under different static loads are obtained, and vibration data of each position of the bridge under applied dynamic loads are obtained; according to the data distribution change and fluctuation degree of each position of the bridge under different static loads, and in combination with the nonlinear change characteristics of the data, abnormal values of stress change of the bridge and abnormal values of deflection data change of the bridge are obtained, so as to obtain abnormal coefficients of stress deformation of the bridge; the significant values of vibration abnormality of each position under the dynamic loads are obtained, and then the comprehensive deviation coefficients of each position under the action of multiple loads are obtained, so as to calculate the vulnerability values of each position of the bridge; the grid size in the construction process of the finite element model of the bridge is adjusted; and the bearing capacity of the bridge under different loads is statistically obtained based on the finite element model of the bridge. The application can improve the accuracy of the evaluation result of the bridge bearing capacity.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of bridge bearing capacity evaluation, and particularly relates to a precise evaluation method for bridge bearing capacity. BACKGROUND

[0002] The bridge bears a large number of vehicles and pedestrians, and if the bridge structure has a bearing capacity problem, a serious accident may occur, endangering public safety. For a newly built wide hollow slab bridge, precise evaluation of the bearing capacity can verify the quality of bridge design and construction. The wide hollow slab bridge structure is complex, and in actual use, it is often subjected to the combined action of multiple complex loads. The traditional method relies on theoretical calculation for bearing capacity evaluation, but this method is difficult to accurately reflect the influence of local stress concentration and crack propagation deformation on the bearing capacity of the bridge. The influence of multiple load actions on the local stress and deformation characteristics of the bridge is not fully considered, resulting in inaccurate evaluation results and difficulty in truly reflecting the actual stress state and bearing capacity of the bridge.

[0003] A bridge bearing capacity detection device and detection method are disclosed in CN110672425A, which simulates different load conditions and uses a total station to measure displacement and deformation under different loading states to evaluate the bearing capacity of the bridge. The influence of local stress concentration is not fully considered, and the evaluation results are not accurate enough. SUMMARY

[0004] To solve the above technical problems, the application provides a precise evaluation method for bridge bearing capacity to solve the existing problems.

[0005] The precise evaluation method for bridge bearing capacity provided by the application adopts the following technical scheme:

[0006] One embodiment of the application provides a precise evaluation method for bridge bearing capacity, comprising the following steps:

[0007] Obtain stress data and deflection data of each position of the bridge under different static loads, and obtain vibration data of each position of the bridge under applied dynamic loads;

[0008] For the stress data and deflection data of each position, according to the distribution change and fluctuation degree of the data of each position of the bridge under different static loads, and in combination with the nonlinear change characteristics of the data, abnormal values of the stress change of each position of the bridge and abnormal values of the deflection data change of the bridge are obtained, and then abnormal coefficients of the stress deformation of each position of the bridge are obtained;

[0009] According to the abnormal degree of vibration data of each position of the bridge and the deviation characteristics of the vibration data in the frequency domain, the significant value of vibration abnormality of each position under dynamic load is obtained, to combine the abnormal coefficient to form the abnormal characteristic vector of each position of the bridge, analyze the difference degree between the abnormal characteristic vectors of different positions, obtain the comprehensive deviation coefficient of each position under the action of multiple loads, and combine the average level of the abnormal characteristic vector of each position to obtain the vulnerability value of each position of the bridge.

[0010] The grid size in the process of building the finite element model of the bridge is adjusted through the vulnerability value of each position, and the bearing capacity of the bridge under different loads is statistically evaluated based on the built finite element model of the bridge.

[0011] Preferably, the calculation method of the stress change abnormal value of each position of the bridge is:

[0012] In the formula, D is the stress change abnormal value of the current position of the bridge, A is the stress change significance of the current position, B is the stress nonlinear change proportion coefficient of the current position, and C is the determination coefficient of the fitting curve corresponding to the stress sequence of the current position, wherein the stress sequence of each position is obtained by arranging the stress data of each position from small to large according to the static load, and the fitting curve of the stress sequence is obtained by fitting.

[0013] Preferably, the product of the average slope of all points on the fitting curve and the range of the stress sequence is taken as the stress change significance of the current position; the maximum mutation point is taken as the demarcation point between linear growth and nonlinear growth of the stress data of the current position by statistically analyzing the mutation points in all slopes; and the ratio of the number of slopes after the demarcation point to the total number of all slopes is taken as the stress nonlinear change proportion coefficient of the current position.

[0014] Preferably, the abnormal coefficient of the stress deformation of each position of the bridge is the average value of the stress change abnormal value and the deflection data change abnormal value of each position of the bridge.

[0015] Preferably, the calculation method of the significant value of vibration abnormality of each position under dynamic load is:

[0016] In the formula, H is the significant value of vibration abnormality of the current position under dynamic load, F is the local vibration abnormality significant coefficient of the current position, and G is the difference value of the natural frequency between the current position and other positions.

[0017] Preferably, all abnormal values in the vibration data of the current position are extracted, the difference between each abnormal value and the average value of all non-abnormal values is calculated, and the absolute value is taken, and the cumulative sum of all absolute values is taken as the local vibration abnormality significant coefficient of the current position.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] Preferably, adjusting the mesh size during the bridge finite element model construction process further includes:

[0022] 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.

[0023] This application has at least the following beneficial effects:

[0024] 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

[0025] 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.

[0026] Figure 1A flow chart of steps of a precise evaluation method of bridge bearing capacity provided by the present application. DETAILED DESCRIPTION

[0027] In order to further clarify the technical means and effects taken by the present application to achieve the predetermined purposes, the following describes in detail the specific embodiments, structures, features and effects of a precise evaluation method of bridge bearing capacity according to the present application, in combination with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0028] Unless otherwise defined, such as the term "comprise", "include" or any other variant thereof is intended to cover non-exclusive inclusion, so that the circuit structure, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such article or device. Without more limitation, the element defined by the phrase "comprising one" does not exclude the presence of additional identical elements in the article or device including the element. In addition, the term "and / or" used herein includes any and all combinations of one or more related listed items. All technical and scientific terms used herein have the same meaning as understood by those skilled in the art to which the present application belongs.

[0029] The specific scheme of the precise evaluation method of bridge bearing capacity provided by the present application is specifically described below in combination with the accompanying drawings.

[0030] The precise evaluation method of bridge bearing capacity provided by one embodiment of the present application, in particular, please refer to Figure 1 , including the following steps:

[0031] Step 1: Obtain stress data and deflection data of each position of the bridge under different static loads, and obtain vibration data of each position of the bridge under applied dynamic load.

[0032] In practical applications, bridge design must fully consider the maximum load it may bear and its performance under dynamic load to ensure its safety and reliability. In this embodiment, the static load and dynamic load experiments are combined to detect the bearing capacity of the newly built wide hollow slab bridge. The static load experiment can simulate the maximum load that the bridge may bear in actual use, and by gradually increasing the static load on the bridge, the stress and deflection changes at different positions are measured, which helps to find possible local damage and crack problems in the bridge structure. The dynamic load experiment can evaluate the impact of various dynamic loads on the bridge in actual use, such as vehicle travel, wind vibration, and earthquakes. By analyzing the vibration frequency and amplitude under dynamic load, the dynamic performance of the bridge is analyzed to determine whether it meets the requirements.

[0033] In the static load experiment, the static load is gradually increased by a step-by-step loading method in this embodiment, and strain gauges are installed in each geometric region of the bridge to collect stress data, such as the midspan, support points, and other positions. A total station is used to obtain deflection data at the same positions.

[0034] Thus, the stress data and deflection data of the bridge at different positions under different static loads are obtained. In the dynamic load experiment, a vibration exciter is used to apply dynamic load to the bridge, and a vibration sensor is used to obtain vibration data at each position of the bridge under dynamic load, thereby obtaining the vibration data at each position under dynamic load.

[0035] Step two: Based on the distribution changes and fluctuation levels of the stress data and deflection data at each position under different static loads, and combined with the nonlinear variation characteristics of the data, the abnormal values of the stress variation and the deflection data variation at each position of the bridge are obtained, and then the abnormal coefficients of the stress deformation at each position of the bridge are obtained.

[0036] By monitoring the stress and deflection changes at different positions, not only can the actual stress state of the bridge under different load levels be analyzed, but also potential structural problems can be found in time, providing a scientific basis for the safe operation and maintenance management of the bridge. With the increase of static load, the corresponding stress and deflection states at different positions also differ. For example, the midspan position is the most concentrated part of the bridge stress and deformation, and bears a large bending stress and deflection deformation, so the stress and deflection at the midspan position usually increase gradually with the increase of load, and the growth rate is relatively fast. In contrast, the stress and deflection growth at some positions is relatively flat, such as the support points, because the structure at the support points is constrained by the support, which can better disperse the load and thus alleviate the accumulation of stress and deflection to some extent. In addition, when the load reaches a certain value, the stress and deflection data at some positions may change abruptly. Therefore, the stress and deflection variation characteristics during the static load loading process are processed as follows.

[0037] Firstly, the stress and deflection data collected at each position are arranged in order of static load from small to large, and the corresponding stress sequence and deflection sequence are obtained. The greater the change amplitude or rate of stress and deflection, the more prone the corresponding bridge position is to failure.

[0038] In this embodiment, taking the stress sequence of any position as an example, a quadratic polynomial fitting technique is used to obtain the fitting curve of the stress sequence at the position, and then the slope at each point on the fitting curve is calculated. The product of the average of all slopes and the range of the stress sequence is taken as the stress change significance at the position, where the stress change significance at the current position is denoted as A. The obtained A reflects the stress change amplitude and rate characteristics of the bridge at the current position under the action of static load.

[0039] In addition, in the early stage of the static load experiment, 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 growth rate of the stress data may slow down, and then non-linear growth may occur. If the non-linear growth stage occurs early, i.e., the linear growth stage is shortened, it indicates that structural damage occurs early at this position, which reduces the carrying capacity of the bridge and increases the discreteness of the stress data. Based on this feature, firstly, the linear growth and non-linear growth processes are divided. Since the slopes at each point in the linear growth process are consistent, the corresponding slopes will change abruptly after entering the non-linear growth stage. Therefore, in this embodiment, a sliding t-test algorithm is used to fit the mutation points of all slope data on the curve, and the maximum mutation point is taken as the dividing point between linear growth and non-linear growth. The ratio of the number of slope data after the dividing point to the total number of all slope data is taken as the stress non-linear change proportion coefficient at the position, where the stress non-linear change proportion coefficient at the current position is denoted as B. The larger the obtained B, the earlier the non-linear growth stage of the stress change at the current position occurs, and the larger the proportion.

[0040] Further, the determination coefficient of the fitting curve corresponding to the stress sequence at each position is calculated, denoted as C. The smaller the obtained C, the greater the discreteness of the stress change at the position. Further, according to the stress change significance and the non-linear change proportion coefficient at each position, the stress change abnormal value of the bridge at each position is obtained, and the specific calculation formula is: where D is the stress change abnormal value of the bridge at the current position, A is the stress change significance at the current position, and B is the stress non-linear change proportion coefficient at the current position. The larger the obtained D, the greater the amplitude and rate of the stress change of the bridge with the increase of the load, and the earlier the structural damage occurs at the position.

[0041] In the static load process, the deflection data change is consistent with the stress data change as a whole, therefore, in order to better reflect the state of the bridge under different load conditions, for the deflection data of each position, the same calculation steps as described above in the embodiment are adopted, and correspondingly, the abnormal value of the deflection data change of each position of the bridge.

[0042] Further, in combination with the change characteristics of the stress and deflection data, the average value of the abnormal value of the stress change and the abnormal value of the deflection data change of each position of the bridge is taken as the abnormal coefficient of the stress deformation of each position of the bridge, and the abnormal coefficient of the stress deformation of the current position of the bridge is denoted as E. The obtained E reflects the abnormal degree of all stress and deformation degree under the action of the static load.

[0043] Step three: according to the abnormal degree of the vibration data of each position of the bridge and the deviation characteristics of the vibration data in the frequency domain, the significant value of the vibration abnormality of each position under the action of the dynamic load is obtained, the abnormal representation vectors of each position of the bridge are formed in combination with the abnormal coefficient, the difference degree between the abnormal representation vectors of different positions is analyzed, the comprehensive deviation coefficient of each position under the action of the multiple load is obtained, and in combination with the average level of the abnormal representation vectors of each position, the vulnerability value of each position of the bridge is obtained.

[0044] Further, in the dynamic load process, the vibration data collected at different positions should have certain similarity and consistency, if the vibration data of a position obviously deviates from other positions, it is more likely that there is a local damage or structural defect in the position. Specifically, at the vulnerable position, the corresponding vibration data is more likely to have obvious local abnormal value. In addition, under the action of the dynamic load, the bridge has a certain natural frequency, and the natural frequencies of different positions may be slightly different, but should be consistent in general. If the natural frequency of a position obviously deviates from other positions, it also indicates that the position is more likely to have a defect.

[0045] Therefore, taking the vibration data at any position as an example, in the embodiment, all abnormal values in the vibration data of the position are obtained by using the SOS (Stochastic Outlier Selection) detection algorithm, then the mean value of the data corresponding to all non-abnormal values is calculated, the difference between each abnormal value and the mean value is calculated respectively, the absolute value is taken, the cumulative sum of all absolute values is counted, which is used to represent the significant coefficient of the local vibration abnormality of the position caused by the dynamic load, in the embodiment, the cumulative sum of all absolute values corresponding to the current position is taken as the local vibration abnormality significant coefficient of the current position, denoted as F. The larger the obtained F is, the more obvious the local abnormal value of the vibration data of the current position under the action of the dynamic load is.

[0046] Meanwhile, in the embodiment, the discrete Fourier transform technology is used to obtain the frequency spectrum diagram of the vibration data collected at each position, and the spectral centroid of each frequency spectrum diagram is obtained, which reflects the frequency of the position with the most concentrated energy in the frequency spectrum diagram. Then, the cumulative sum of the difference between the frequency corresponding to the spectral centroid at this position and the frequencies corresponding to the spectral centroids of all other positions is calculated as the difference value of the natural frequency between this position and other positions. In the embodiment, the difference value of the natural frequency between the current position and other positions is denoted as G. The larger the obtained G is, the more significantly the natural frequency of the current position of the bridge deviates from other positions.

[0047] Thus, the significant value of the vibration anomaly of each position under dynamic load is calculated, and the formula is: In the formula, H is the significant value of the vibration anomaly of the current position under dynamic load, F is the local vibration anomaly significant coefficient of 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 vibration local anomaly and the deviation characteristics of the natural frequency of the current position of the bridge under dynamic load.

[0048] After the above steps, the changes and state characteristics of the relevant parameters of the bridge at multiple positions under static load and dynamic load are obtained, which reflect the state of the bridge under different loads.

[0049] Further, in practical applications, a wide hollow slab bridge needs to have good static load and dynamic load capacity. Under normal circumstances, stress concentration and large deformation easily occur in some key areas of the bridge, which further causes the significant value of the abnormal coefficient of the bridge stress and deformation and the vibration local anomaly and the deviation of the natural frequency of these positions to be large and significantly different from other positions as the static load increases.

[0050] Therefore, in the embodiment, the abnormal coefficient of the bridge stress and deformation and the significant value of the vibration anomaly under dynamic load of each position are combined to form the abnormal representation vector of each position. Further, preferably, in the embodiment, the mean value of the Euclidean distance between the abnormal representation vector of each position and the corresponding abnormal representation vectors of all other positions is calculated as the comprehensive deviation coefficient of the position under multiple loads.

[0051] The comprehensive deviation coefficient reflects the difference characteristics of the corresponding structural damage degree between the position and other positions of the bridge under different loads. Further, the product of the comprehensive deviation coefficient of each position and the mean value of the data in the corresponding abnormal representation vector of each position is taken as the vulnerability value of each position of the bridge, which is used to reflect the vulnerability characteristics of the corresponding position of the bridge under multiple loads.

[0052] Step 4: Adjust the grid size in the process of constructing the finite element model of the bridge through the vulnerability value of each position, and evaluate the bearing capacity of the bridge under different loads based on the constructed finite element model of the bridge.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] It is to be understood that the phase "one embodiment" or "some embodiments" or the like means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the application. The appearances of the phrase "in one embodiment" or "in some embodiments" in various places in the specification are not necessarily all referring to the same embodiment, although it can. Furthermore, the term "comprises" or "comprising" or the like is used in the sense of "including but not limited to" unless otherwise noted.

[0058] It should be noted that the above-mentioned order of the embodiments of the application is only for description, and does not represent the advantages and disadvantages of the embodiments. Moreover, the above-mentioned description is made for the specific embodiments of the specification. In addition, the processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multi-task processing and parallel processing are possible or can be advantageous. At the same time, the size of the serial number of each step in the embodiments does not mean the order of execution, and the execution order of each process should be determined by its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments in the specification.

[0059] The above embodiments are only used to illustrate the technical solutions of the application, rather than limit them; although the application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for some technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the application, and should be included in the protection scope of the application.

Claims

1. A method for accurate assessment of the load-carrying capacity of a bridge, characterized in that, The method comprises the following steps: Obtaining stress data and deflection data of each position of the bridge under different static loads, and obtaining vibration data of each position of the bridge under applied dynamic load; According to the distribution change and fluctuation degree of the stress data and deflection data of each position under different static loads, and combining the nonlinear change characteristics of the data, the abnormal values of the stress change and the deflection data change of each position of the bridge are obtained, and then the abnormal coefficient of the stress deformation of each position of the bridge is obtained; According to the abnormal degree of the vibration data of each position of the bridge and the deviation characteristics of the vibration data in the frequency domain, the significant value of the vibration abnormality of each position under dynamic load is obtained, and the abnormal representation vectors of each position are formed by combining the abnormal coefficient, the difference degree between the abnormal representation vectors of different positions is analyzed, the comprehensive deviation coefficient of each position under the action of multiple loads is obtained, and the damage degree value of each position of the bridge is obtained by combining the average level of the abnormal representation vectors of each position; The grid size in the process of constructing the finite element model of the bridge is adjusted through the damage degree value of each position, and the bearing capacity of the bridge under different loads is statistically evaluated based on the constructed finite element model of the bridge; The abnormal coefficient of the stress deformation of each position of the bridge is the average value of the abnormal values of the stress change and the deflection data change of each position of the bridge; The calculation method of the significant value of the vibration abnormality of each position under dynamic load is: In the formula, H is the significant value of the current position under dynamic load vibration anomaly, F is the significant coefficient of the current position local vibration anomaly, and G is the difference value of the natural frequency between the current position and other positions. The comprehensive deviation coefficient of each position under the action of multiple loads is the average value of the distance between the abnormal representation vector of each position and the abnormal representation vectors of all other positions; The damage degree value of each position of the bridge is the product of the comprehensive deviation coefficient of each position and the average value of the data in the abnormal representation vector of each position.

2. A method of accurately assessing the load carrying capacity of a bridge as claimed in claim 1 wherein, The calculation method of the abnormal value of the stress change of each position of the bridge is: In the formula, D is the current position bridge stress change anomaly value, A is the stress change significance of the current position, B is the stress nonlinear change proportion coefficient of the current position, and C is the determination coefficient of the stress sequence corresponding to the fitting curve of the current position. The stress data of each position is arranged in ascending order of static load to obtain the stress sequence of each position, and the fitting curve of the stress sequence is obtained by fitting.

3. A method of accurately assessing the load carrying capacity of a bridge as claimed in claim 2 wherein, The product of the average value of the slope of all points on the fitting curve and the stress sequence range is taken as the stress change significant degree of the current position, the maximum mutation point is taken as the demarcation point between the linear growth and the nonlinear growth of the stress data of the current position, and the ratio of the number of slopes after the demarcation point to the total number of all slopes is taken as the nonlinear change proportion coefficient of the current position stress.

4. The method for precise evaluation of the bearing capacity of a bridge according to claim 1, characterized in that, All abnormal values in the vibration data of the current position are extracted, the difference between each abnormal value and the average value of all non-abnormal values is calculated, and the absolute value is taken, and the cumulative sum of all absolute values is taken as the local vibration abnormal significant coefficient of the current position.

5. The method for precise evaluation of the bearing capacity of a bridge according to claim 1, characterized in that, The frequency spectrum diagram corresponding to the vibration data of the current position is extracted, the spectral centroid of the frequency spectrum diagram is obtained, the difference between the frequency corresponding to the spectral centroid of the current position and the frequency corresponding to the spectral centroid of all other positions is calculated, and the difference value of the natural frequency between the current position and other positions is taken as the difference value.

6. The method for precise evaluation of the bearing capacity of a bridge according to claim 1, characterized in that, The adjustment of the grid size in the process of constructing the finite element model of the bridge further comprises: Normalizing all the vulnerability degree values, setting a vulnerability degree threshold , if the vulnerability degree value is greater than or equal to , the grid size of the corresponding geometric region at the corresponding position in the bridge finite element model construction process is reduced to of the preset initial grid size , if the vulnerability degree value is less than , the grid size of the corresponding geometric region at the corresponding position is the preset initial grid size.

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