Bridge evaluation method and system based on steady-state excitation

Abstract

The invention discloses a bridge assessment method and system based on steady-state excitation, and the method comprises the steps: determining the excitation frequency and the excitation amplitude under a current working condition according to a first parameter of a target mode and the excitation quality, and applying steady-state excitation to a bridge; calculating a second parameter of the target modal according to the excitation mass, the excitation amplitude and the bridge structure data in the excitation process and after the excitation is stopped; correcting the basic finite element model in combination with the current bridge member parameter and the second parameter of the target modal; and evaluating the bearing capacity of the bridge by utilizing a calculation result of the corrected finite element model. According to the method, the stable excitation is applied to the bridge, so that the bridge generates stable single-mode vibration, the calculation accuracy of the second parameter of the target mode can be effectively improved, the correction precision of the finite element model is further improved, the calculation result of the corrected finite element model is more accurate, and the accuracy of a bridge evaluation result is improved.

Description

Technical Field

[0001] This application relates to the field of bridge inspection technology, specifically to a bridge evaluation method and system based on steady-state vibration. Background Technology

[0002] Cross-river bridges, as crucial hubs in transportation networks, play an indispensable role in national economic and social development. However, due to their long-term exposure to complex natural environments and the continuous traffic loads they bear, coupled with the gradual aging of their structures over time, their structural performance inevitably changes. To ensure that cross-river bridges remain in a safe and reliable operating state, regular, comprehensive, and accurate inspections and evaluations are essential, and load testing is one of the most effective testing methods.

[0003] In traditional static load tests of bridges, deploying a large number of heavy vehicles to simulate actual operational loads not only faces difficulties in vehicle allocation, traffic disruption, and bridge closure, but may also affect structural safety and surrounding traffic, making the testing work difficult to carry out smoothly. Traditional dynamic load tests, when evaluating the dynamic performance of long-span bridges, suffer from poor excitation effects and low accuracy in detecting bridge modal parameters, resulting in incomplete and uncontrollable test results that fail to accurately reflect the true dynamic characteristics of the bridge.

[0004] Although most long-span bridges are now equipped with comprehensive health monitoring systems, which has to some extent solved the problem of deploying sensors across the entire bridge during the static and dynamic load testing phase of traditional bridges and reduced safety risks, the existing finite element models inevitably differ from the actual state of the bridge, requiring correction based on the bridge's actual response data. However, in current bridge evaluation techniques, the small amplitude of the bridge response, the complex frequency components, and the unknown load information make it difficult to achieve high-precision correction of the finite element model, resulting in low accuracy of bridge evaluation results. Summary of the Invention

[0005] This application provides a bridge evaluation method and system based on steady-state excitation, which can solve the technical problem of low accuracy of evaluation results in current cross-river bridge evaluation technology.

[0006] To achieve the above objectives, in a first aspect, this application provides a bridge evaluation method based on steady-state excitation, the method comprising: Under the current working conditions, the excitation frequency and excitation amplitude are determined based on the first parameter of the target mode and the excitation mass, and steady-state excitation is applied to the bridge.

[0007] The second parameter of the target mode is calculated based on the excitation mass, excitation amplitude, and bridge structure data during and after excitation.

[0008] The basic finite element model is modified by combining the current bridge component parameters and the second parameter of the target mode.

[0009] The load-bearing capacity of the bridge is evaluated using the calculation results of the modified finite element model.

[0010] Furthermore, in one embodiment, the first parameter of the target mode is obtained from: historical bridge inspection data, monitoring data obtained using a bridge health monitoring system, or calculation using a basic finite element model.

[0011] Furthermore, in one embodiment, determining the excitation frequency and excitation amplitude based on the first parameter of the target mode and the excitation mass includes: The first parameters of the target mode include the first frequency of the target mode, the first mass of the target mode, the first mode shape of the target mode, the first damping ratio of the target mode, and the first amplitude of the target mode.

[0012] The first frequency of the target mode is used as the excitation frequency.

[0013] The excitation amplitude is determined based on the excitation mass, the first mass of the target mode, the first mode shape of the target mode, the first damping ratio of the target mode, and the first amplitude of the target mode.

[0014] Furthermore, in one embodiment, calculating the second parameter of the target mode based on the excitation mass, excitation amplitude, and bridge structure data during and after excitation includes: The bridge structural data includes vibration response data after excitation stops and steady-state amplitude during the excitation process.

[0015] The second parameters of the target mode include the second frequency of the target mode, the second damping ratio of the target mode, the second mode shape of the target mode, and the second mass of the target mode.

[0016] The second frequency of the target mode is obtained by performing a Fourier transform on the vibration response data.

[0017] The target mode second damping ratio is obtained by fitting the vibration response data.

[0018] The second mode shape of the target mode is obtained by normalizing the steady-state amplitude.

[0019] The second mass of the target mode is calculated using the second mode shape, the second damping ratio of the target mode, the steady-state amplitude, the excitation mass, and the excitation amplitude.

[0020] Furthermore, in one embodiment, the vibration response data includes: acceleration response data, velocity response data, or displacement response data.

[0021] Furthermore, in one embodiment, the step of modifying the basic finite element model by combining the current bridge component parameters and the second parameter of the target mode includes: Sensitivity analysis is performed on the current bridge component parameters to determine the bridge component parameters that need to be corrected.

[0022] The first parameter of the target mode is calculated using a basic finite element model based on the parameters of the bridge component to be corrected, and then the objective function is constructed by combining the first parameter with the second parameter of the target mode.

[0023] The finite element model based on the parameters of the bridge component to be corrected when the objective function value is minimized is the corrected finite element model.

[0024] Furthermore, in one embodiment, the evaluation of the bridge's load-bearing capacity using the calculation results of the modified finite element model includes: Based on the revised finite element model and the preset bridge load, calculate the response parameters of the bridge components; The bridge's load-bearing capacity is assessed based on the calculated response parameters of the bridge components and the preset evaluation criteria. The response parameters of the bridge components include the deformation of the bridge components, the internal forces of the bridge components, and the strain of the bridge components.

[0025] Furthermore, in one embodiment, the preset bridge load includes: static load, dynamic load, environmental load, or a combination of multiple loads.

[0026] Secondly, based on the aforementioned bridge evaluation method based on steady-state excitation, this application provides a bridge evaluation system based on steady-state excitation, the system comprising: The excitation module is used to determine the excitation frequency and excitation amplitude based on the first parameter of the target mode and the excitation mass under the current working conditions, and to apply steady-state excitation to the bridge.

[0027] The calculation module is used to calculate the second parameter of the target mode based on the excitation mass, excitation amplitude, and bridge structure data during and after excitation.

[0028] The correction module is used to correct the basic finite element model by combining the current bridge component parameters and the second parameter of the target mode.

[0029] The evaluation module is used to assess the load-bearing capacity of the bridge using the calculation results of the modified finite element model.

[0030] Furthermore, in one embodiment, the system further includes a sensitivity module for performing sensitivity analysis on the current bridge component parameters in the correction module.

[0031] The beneficial effects of the technical solutions provided in this application include: This application determines the excitation frequency and amplitude based on the first parameter and excitation mass of the target mode under current operating conditions, and applies steady-state excitation to the bridge. It then calculates the second parameter of the target mode based on the excitation mass, amplitude, and bridge structural data during and after excitation. Finally, it modifies the basic finite element model by combining the current bridge component parameters and the second parameter of the target mode. The bridge's load-bearing capacity is evaluated using the calculation results from the modified finite element model. By applying steady-state excitation to the bridge, a stable single-mode vibration is generated. This effectively improves the accuracy of the second parameter calculation when using bridge structural data during and after excitation. Furthermore, the modification accuracy of the basic finite element model is improved when modifying it using the current bridge component parameters and the second parameter of the target mode, resulting in more accurate calculation results and thus enhancing the accuracy of the bridge evaluation. Attached Figure Description

[0032] Figure 1 This is a flowchart of a bridge evaluation method based on steady-state excitation, as described in an embodiment of this application.

[0033] Figure 2 This is a schematic diagram of the acceleration response simulation in an embodiment of this application.

[0034] Figure 3 This is a block diagram of a bridge evaluation system based on steady-state excitation, as described in an embodiment of this application. Detailed Implementation

[0035] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present application.

[0036] It should be noted that this application strictly references the requirements of bridge specifications such as the "Specifications for Testing and Evaluation of Load-Bearing Capacity of Highway Bridges" to conduct a comprehensive and scientific evaluation of the bridge's load-bearing capacity, including: (1) Multi-condition analysis and calculation: A full analysis and calculation of various working conditions for the ultimate limit state and serviceability limit state is carried out. The bearing capacity performance of the bridge under different loads and load combinations and different structural stress states is considered to ensure the comprehensiveness and accuracy of the evaluation results.

[0037] (2) Comprehensive evaluation: Taking into account the modal parameters, material properties, historical test data and finite element model correction results of the bridge, the load-bearing capacity of the bridge is evaluated in accordance with relevant specifications and standards, so as to provide important decision-making basis for the maintenance, repair and management of the bridge.

[0038] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0039] In one aspect, this application provides an embodiment of a bridge evaluation method based on steady-state excitation.

[0040] In this embodiment, see Figure 1 As shown, the bridge evaluation method based on steady-state excitation includes: S1. Under the current working conditions, determine the excitation frequency and excitation amplitude based on the first parameter of the target mode and the excitation mass, and apply steady-state excitation to the bridge.

[0041] S2. Calculate the second parameter of the target mode based on the excitation mass, excitation amplitude, and bridge structure data during and after excitation.

[0042] S3. Modify the basic finite element model by combining the current bridge component parameters and the second parameter of the target mode.

[0043] S4. The load-bearing capacity of the bridge is evaluated using the calculation results of the modified finite element model.

[0044] In this embodiment, by applying steady-state excitation to the bridge, a stable single-mode vibration is generated. The second parameter of the target mode of the bridge is calculated using the bridge structure data during and after the excitation process. This significantly improves the accuracy of the second parameter of the target mode. Based on this, the basic finite element model is corrected using the current bridge component parameters and the second parameter of the target mode, which further improves the accuracy of the finite element model correction. This makes the calculation results of the corrected finite element model more reliable, thereby effectively improving the accuracy of the bridge evaluation results.

[0045] Furthermore, in one embodiment, the first parameter of the target mode in step S1 above can be obtained from: historical bridge inspection data, monitored by a bridge health monitoring system, or calculated using a basic finite element model.

[0046] In this embodiment, the first parameter of the target mode is obtained by utilizing existing health monitoring systems, historical detection data, or basic finite element models, which improves the excitation efficiency, enables a more comprehensive understanding of the bridge structural state, improves the reliability of the detection results, and at the same time reduces the number of sensors and the difficulty of the work during the detection process to a certain extent, thereby reducing safety risks.

[0047] Furthermore, in one embodiment, in step S1 above, steady-state excitation is applied to the bridge using a vibration testing vehicle. The process is divided into multiple working conditions based on the position of the vibration testing vehicle on the main beam of the bridge, with each working condition containing multiple sub-working conditions. In each sub-working condition, the position of the vibration testing vehicle on the main beam of the bridge is fixed, and only the excitation frequency and amplitude are changed to achieve excitation of each target mode of the bridge in that sub-working condition.

[0048] In this embodiment, in order to reduce the interference with normal traffic during the excitation process and the impact of bridge traffic on the excitation effect, the excitation time is selected during a period with relatively low traffic flow (such as 22:00~04:00), and the excitation location is the emergency lane.

[0049] Furthermore, in one embodiment, in step S1 above, the first parameters of the target mode include the first frequency of the target mode, the first mass of the target mode, the first mode shape of the target mode, the first damping ratio of the target mode, and the first amplitude of the target mode. Determining the excitation frequency and excitation amplitude based on the first parameters of the target mode and the excitation mass specifically includes the following steps: S11. Use the first frequency of the target mode as the excitation frequency.

[0050] S12. Determine the excitation amplitude based on the excitation mass, the first mass of the target mode, the first mode shape of the target mode, the first damping ratio of the target mode, and the first amplitude of the target mode. The excitation mass is the mass of the moving mass block of the exciter.

[0051] In this embodiment, the excitation frequency and excitation amplitude are determined based on the first parameter of the target mode and the excitation mass, and steady-state excitation is applied to the bridge according to the excitation frequency and excitation amplitude, so that the bridge generates stable single-mode vibration.

[0052] Furthermore, in one embodiment, step S12 above can derive the calculation formula for the excitation amplitude from the motion equation of the nth mode of the bridge under excitation, and calculate the excitation amplitude in combination with the first amplitude of the target mode, as follows: By performing a Laplace transform on the equation of motion of the nth mode of the bridge under excitation, the steady-state response equation of the nth target mode of the bridge is obtained.

[0053] The equation of motion for the nth mode of a bridge under excitation force is: , in, This represents the mass of the nth target mode of the bridge. This represents the damping of the nth target mode of the bridge. This represents the stiffness of the bridge's nth target mode. Indicates the excitation mass, Indicates the excitation amplitude. Indicates the excitation frequency, The generalized coordinates representing the nth-order target mode of the bridge. This represents the mode shape of the nth target mode at the location of the excitation on the bridge.

[0054] Steady-state response of the nth target mode of the bridge The equation is: , in, This represents the ratio of the excitation frequency to the frequency of the nth target mode of the bridge. This represents the damping ratio of the nth target mode of the bridge.

[0055] Based on the steady-state response equation and mode shape of the nth target mode of the bridge, the amplitude of the nth target mode of the main girder at spanwise position x is obtained. The equation is as follows: , in, This represents the mode shape of the nth target mode of the bridge. This represents the steady-state response of the bridge's nth target mode.

[0056] Since the target modal frequency of the nth order target mode of the bridge is set as the excitation frequency, that is... The amplitude of the nth target mode of the bridge at spanwise position x of the main girder. The equation is: , in, This represents the mode shape of the nth target mode of the bridge.

[0057] This leads to the excitation amplitude. The calculation formula is as follows: .

[0058] Furthermore, in one embodiment, in step S2 above, calculating the second parameter of the target mode based on the excitation mass, excitation amplitude, and bridge structure data during and after excitation includes: The bridge structure data is collected during and after the excitation process. The bridge structure data includes vibration response data after the excitation stops and steady-state amplitude during the excitation process. The vibration response data includes acceleration response data, velocity response data, or displacement response data. The bridge structure data is collected through the bridge health monitoring system, the additional sensors on the excited bridge, and the sensors on the excitation detection vehicle.

[0059] The second parameters of the target mode include the second frequency of the target mode, the second damping ratio of the target mode, the second mode shape of the target mode, and the second mass of the target mode, wherein: The second frequency of the target mode is obtained by performing a Fourier transform on the vibration response data; the second damping ratio of the target mode is obtained by fitting the vibration response data; the second mode shape of the target mode is obtained by normalizing the steady-state amplitude; and the second mass of the target mode is calculated using the second mode shape of the target mode, the second damping ratio of the target mode, the steady-state amplitude, the excitation mass, and the excitation amplitude.

[0060] Furthermore, in one embodiment, see [reference needed]. Figure 2 As shown, in step S2 above, taking acceleration response data as an example, the second parameter of the target mode is calculated based on the excitation mass, excitation amplitude, acceleration response data after excitation stops, and steady-state amplitude during excitation. Specifically, this includes: exist Figure 2 In the steady-state segment, the main girder of the bridge vibrates according to the actual mode shape of the target mode. The steady-state amplitude of the nth order target mode of the bridge at different spanwise positions of the main girder is normalized according to the following formula to obtain the second mode shape of the target mode: , in, This represents the amplitude of the nth target mode of the main girder of the bridge at the spanwise position x. This represents the maximum steady-state amplitude of the nth target mode of the bridge at different spanwise positions of the main girder.

[0061] exist Figure 2 In the free decay state segment (i.e., the stage after excitation stops), the second frequency of the target mode is obtained by performing a Fourier transform on the acceleration response data, and the second damping ratio of the target mode is obtained by fitting the acceleration response data. The fitting formula is as follows: , Where z represents the acceleration response data, z o t represents the initial value of the acceleration response data, and t represents time.

[0062] The second mass of the target mode is calculated based on the second mode shape, the second damping ratio of the target mode, the steady-state amplitude, the excitation mass, and the excitation amplitude. The calculation formula is as follows: .

[0063] Furthermore, in one embodiment, step S3 above, which involves modifying the basic finite element model by combining the current bridge component parameters and the second parameter of the target mode, includes: S31. Perform sensitivity analysis on the current bridge component parameters to determine the bridge component parameters to be corrected. Specifically: S311. Based on the actual technical condition of the bridge and engineering experience, select the current bridge component parameters and calculate the sensitivity of the current bridge component parameters using the following formula: , in, This represents the parameter of the i-th bridge component. Indicates the increment of bridge component parameters. Indicates the number of parameters for bridge components. This represents the j-th parameter of the second parameter of the target mode.

[0064] In this embodiment, the bridge component parameters include elastic modulus, unit weight, moment of inertia of section, and initial stress.

[0065] S312. Select a preset number of bridge component parameters as parameters to be corrected in descending order of sensitivity, and determine the correction range of the bridge component parameters to be corrected.

[0066] The correction range for the bridge component parameters to be corrected is: ,in, This represents the minimum value of the parameter of the i-th bridge component. This represents the maximum value of the parameter of the i-th bridge component.

[0067] S32. Calculate the first parameter of the target mode using the basic finite element model based on the parameters of the bridge components to be corrected, and combine it with the second parameter of the target mode to construct the objective function. Specifically: S321. The parameters of the bridge components to be corrected are sampled using the Latin hypercube design method. Based on the basic finite element model, the first parameter of the target mode corresponding to the parameters of the bridge components to be corrected is calculated to form a sample set. The sample set is then fitted using a spatial interpolation algorithm based on the covariance function to construct a Kriging surrogate model. The Kriging surrogate model formula is as follows: , in, The first parameter matrix represents the target mode. This indicates the number of the first parameters of the target mode. Represents the regression coefficient. This represents a matrix representing a stochastic process.

[0068] S322. The sum of squared residuals of the first parameter of the target mode calculated using the Kriging surrogate model and the second parameter of the target mode calculated in step S2 above is used as the objective function. The objective function equation is: , in, The number of parameters representing the same type of target mode. This represents the first parameter of the target mode calculated by the Kriging surrogate model. This represents the second parameter of the target mode calculated in step S2 above.

[0069] S33. The finite element model of the bridge component parameters to be corrected based on the minimum objective function value is the corrected finite element model.

[0070] In this embodiment, through the above steps, a finite element model that better reflects the actual state of the bridge is obtained based on the correction of the bridge component parameters. This improves the accuracy and reliability of the model and provides a scientific basis for bridge health monitoring and maintenance. By combining sensitivity analysis and the Kriging surrogate model, accurate correction of the bridge component parameters is effectively achieved, ensuring the safety and durability of the bridge structure.

[0071] Furthermore, in one embodiment, step S4, which uses the calculation results of the modified finite element model to evaluate the bridge's load-bearing capacity, includes the following steps: S41. Based on the modified finite element model and the preset bridge load, calculate the response parameter values ​​of the bridge components. The response parameters of the bridge components include the deformation of the bridge components, the internal forces of the bridge components, and the strain of the bridge components. The preset bridge load includes static load, dynamic load, environmental load, or a combination of multiple loads.

[0072] S42. Evaluate the bridge's load-bearing capacity based on the calculated bridge component response parameter values ​​and the preset evaluation criteria.

[0073] Secondly, based on the above-described embodiments of the bridge evaluation method based on steady-state excitation, an embodiment of a bridge evaluation system based on steady-state excitation is provided. See [link to documentation]. Figure 3 As shown, the above system includes: an excitation module, a calculation module, a correction module, and an evaluation module, specifically: The excitation module is used to determine the excitation frequency and excitation amplitude based on the first parameter of the target mode and the excitation mass under the current working conditions, and to apply steady-state excitation to the bridge.

[0074] The calculation module is used to calculate the second parameter of the target mode based on the excitation mass, excitation amplitude, and bridge structure data during and after excitation.

[0075] The correction module is used to correct the basic finite element model by combining the current bridge component parameters and the second parameter of the target mode.

[0076] The evaluation module is used to assess the load-bearing capacity of the bridge using the calculation results of the modified finite element model.

[0077] Furthermore, in one embodiment, the system further includes a sensitivity module for performing sensitivity analysis on the current bridge component parameters in the correction module.

[0078] This application applies steady-state excitation to a bridge and uses bridge structural data during and after the excitation process—that is, the bridge's response data to steady-state excitation—to calculate target modal parameters. The existing bridge finite element model is then dynamically corrected using these target modal parameters, making the model more closely reflect the actual structural state of the bridge. Based on this, a load-bearing capacity assessment can more accurately reflect the bridge's true load-bearing capacity, providing a reliable basis for bridge maintenance decisions and effectively reducing the bias in assessment results that may arise from inaccurate models in current load-bearing capacity assessment methods. Furthermore, the data sources in this application are extensive, including historical bridge inspection data, bridge health monitoring systems, and basic finite element models; therefore, it improves the comprehensiveness of the data in the bridge assessment process, thereby enhancing the accuracy of the assessment results.

[0079] It should be noted that the sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0080] The terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus. The terms "first," "second," and "third," etc., are used to distinguish different objects, etc., and do not indicate a sequence, nor do they limit "first," "second," and "third" to different types.

[0081] In the description of the embodiments of this application, terms such as "exemplary," "for example," or "for instance" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplary," "for example," or "for instance" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary," "for example," or "for instance" is intended to present the relevant concepts in a concrete manner.

[0082] In the description of the embodiments of this application, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The "and / or" in the text is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of this application, "multiple" means two or more.

[0083] In some processes described in the embodiments of this application, multiple operations or steps are included in a specific order. However, it should be understood that these operations or steps may not be executed in the order they appear in the embodiments of this application, or they may be executed in parallel. The sequence number of the operation is only used to distinguish different operations, and the sequence number itself does not represent any execution order. In addition, these processes may include more or fewer operations, and these operations or steps may be executed sequentially or in parallel, and these operations or steps may be combined.

[0084] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes several instructions to cause a terminal device to execute the methods described in the various embodiments of this application.

[0085] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A bridge evaluation method based on steady-state excitation, characterized in that, The method includes: Under the current working conditions, the excitation frequency and excitation amplitude are determined based on the first parameter of the target mode and the excitation mass, and steady-state excitation is applied to the bridge. The second parameter of the target mode is calculated based on the excitation mass, excitation amplitude, and bridge structure data during and after excitation. The basic finite element model is modified by combining the current bridge component parameters and the second parameter of the target mode; The load-bearing capacity of the bridge is evaluated using the calculation results of the modified finite element model.

2. The bridge evaluation method based on steady-state excitation as described in claim 1, characterized in that, The first parameter of the target mode can be obtained from: historical bridge inspection data, bridge health monitoring system, or basic finite element model.

3. The bridge evaluation method based on steady-state excitation as described in claim 1, characterized in that, The step of determining the excitation frequency and excitation amplitude based on the first parameter of the target mode and the excitation mass includes: The first parameters of the target mode include the first frequency of the target mode, the first mass of the target mode, the first mode shape of the target mode, the first damping ratio of the target mode, and the first amplitude of the target mode; The first frequency of the target mode is used as the excitation frequency; The excitation amplitude is determined based on the excitation mass, the first mass of the target mode, the first mode shape of the target mode, the first damping ratio of the target mode, and the first amplitude of the target mode.

4. The bridge evaluation method based on steady-state excitation as described in claim 1, characterized in that, The calculation of the second parameter of the target mode based on the excitation mass, excitation amplitude, and bridge structure data during and after excitation includes: The bridge structure data includes vibration response data after excitation stops and steady-state amplitude during the excitation process; The second parameters of the target mode include the second frequency of the target mode, the second damping ratio of the target mode, the second mode shape of the target mode, and the second mass of the target mode; The second frequency of the target mode is obtained by performing a Fourier transform on the vibration response data; The target mode second damping ratio is obtained by fitting the vibration response data; The second mode shape of the target mode is obtained by normalizing the steady-state amplitude; The second mass of the target mode is calculated using the second mode shape, the second damping ratio of the target mode, the steady-state amplitude, the excitation mass, and the excitation amplitude.

5. The bridge evaluation method based on steady-state excitation as described in claim 4, characterized in that, The vibration response data includes: acceleration response data, velocity response data, or displacement response data.

6. The bridge evaluation method based on steady-state excitation as described in claim 1, characterized in that, The modification of the basic finite element model by combining the current bridge component parameters and the second parameter of the target mode includes: Sensitivity analysis is performed on the current bridge component parameters to determine the bridge component parameters that need to be corrected. The first parameter of the target mode is calculated using a basic finite element model based on the parameters of the bridge component to be corrected, and then the objective function is constructed by combining the second parameter of the target mode. The finite element model based on the parameters of the bridge component to be corrected when the objective function value is minimized is the corrected finite element model.

7. The bridge evaluation method based on steady-state excitation as described in claim 1, characterized in that, The assessment of bridge load-bearing capacity using the calculation results of the modified finite element model includes: Based on the revised finite element model and the preset bridge load, calculate the response parameters of the bridge components; The bridge's load-bearing capacity is assessed based on the calculated response parameters of the bridge components and the preset evaluation criteria. The response parameters of the bridge components include the deformation of the bridge components, the internal forces of the bridge components, and the strain of the bridge components.

8. The bridge evaluation method based on steady-state excitation as described in claim 7, characterized in that, The preset bridge loads include: static loads, dynamic loads, environmental loads, or combinations of multiple loads.

9. A bridge evaluation system based on the steady-state excitation-based bridge evaluation method according to any one of claims 1-8, characterized in that, The system includes: The excitation module is used to determine the excitation frequency and excitation amplitude based on the first parameter of the target mode and the excitation mass under the current working conditions, and to apply steady-state excitation to the bridge. The calculation module is used to calculate the second parameter of the target mode based on the excitation mass, excitation amplitude, and bridge structure data during and after excitation. The correction module is used to correct the basic finite element model by combining the current bridge component parameters and the second parameter of the target mode; The evaluation module is used to assess the load-bearing capacity of the bridge using the calculation results of the modified finite element model.

10. The bridge evaluation system based on steady-state excitation as described in claim 9, characterized in that, The system also includes a sensitivity module, which is used to perform sensitivity analysis on the current bridge component parameters in the correction module.

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