Simply supported girder bridge main girder technical condition evaluation method based on piezoelectric rubber support

Abstract

The invention relates to the technical field of engineering detection and monitoring, and discloses a method for evaluating the technical condition of a simply supported girder bridge girder based on a piezoelectric rubber support, and the method comprises the following steps: S1, data collection: collecting the initial state data of the simply supported girder bridge girder, and recording the initial rigidity of the girder and the potential value at the support; s2, disease influence analysis: carrying out reverse analysis on bearing capacity change caused by overall or local diseases of the simply supported girder bridge girder to obtain a change value of rigidity degradation of the girder; and S3, potential change detection: detecting the potential change of the piezoelectric patch pre-buried in the support in real time according to the corner change at the bridge support caused by the rigidity change of the main beam. According to the invention, real-time and automatic assessment of the technical condition of the bridge girder is realized, the rigidity degradation of the girder can be accurately quantified, the disease development trend is predicted in combination with historical data, the accuracy and foresight of bridge health management are effectively improved, the maintenance cost is reduced, and the safety is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of engineering detection and monitoring, and in particular to a method for evaluating the technical condition of a main beam of a simply supported beam bridge based on a piezoelectric rubber bearing. Background Art

[0002] As an important structural form of highway and railway bridges, the technical condition of the main beam of a simply supported beam bridge directly affects the bearing capacity and service life of the bridge. During the long-term service of a simply supported beam bridge, it is affected by various static and dynamic loads and environmental factors, and the main beam may suffer from cracks, material aging, fatigue and other defects, resulting in stiffness degradation. In order to ensure the safety of the bridge, the technical condition assessment of the main beam is the key to bridge maintenance and management.

[0003] At present, the evaluation methods for the technical condition of the main beam of a simply supported beam bridge mainly include regular manual inspection and stress, displacement and other sensor monitoring. Manual inspection mainly relies on the judgment of bridge inspectors on the appearance of bridge defects, supplemented by ultrasonic testing, radar detection and other means to identify internal structural problems. Sensor monitoring, on the other hand, uses strain gauges, displacement sensors and other equipment to obtain real-time data on the physical changes of the bridge.

[0004] However, in the existing technology, manual inspection is affected by subjective factors, has a long cycle, and has poor real-time performance. Stress and displacement sensor monitoring is still insufficient in data quantification, making it difficult to accurately evaluate the stiffness degradation of the main beam and predict the development trend of the disease. Therefore, the existing methods have obvious deficiencies in the automation, real-time and quantitative evaluation of the technical condition of the main beam of a simply supported beam bridge. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a method for evaluating the technical condition of the main beam of a simply supported beam bridge based on piezoelectric rubber bearings, which solves the problems in the prior art that the technical condition assessment of the main beam of the bridge is poor in real time, is greatly affected by subjective factors, is difficult to quantify the degradation of the main beam stiffness, and cannot effectively predict the development trend of the disease.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: a method for evaluating the technical condition of a main beam of a simply supported beam bridge based on a piezoelectric rubber bearing, the method comprising the following steps:

[0007] S1. Data collection: Collect the initial state data of the main beam of the simply supported beam bridge, and record the initial stiffness of the main beam and the potential value at the support;

[0008] S2. Analysis of the impact of damage: by reversely analyzing the change in the bearing capacity caused by the overall or local damage of the main beam of the simply supported beam bridge, the change value of the main beam stiffness degradation is obtained;

[0009] S3, potential change detection: according to the change of the rotation angle at the bridge support caused by the change of the main beam stiffness, the potential change of the piezoelectric sheet embedded in the support is detected in real time;

[0010] S4. Status assessment: Based on the bearing capacity standard for the technical condition level of bridges in the Highway Bridge and Culvert Maintenance Specifications (JTG5120-2021), analyze the potential change law of the embedded piezoelectric plates in the bearings to determine the technical condition level of the bridge;

[0011] S5. Construction of technical condition assessment standard: Based on the relationship between the main beam stiffness degradation rate and the potential change rate, a quantitative assessment standard for the technical condition of the bridge is constructed;

[0012] S6. Implementation of intelligent assessment: Using the potential change data of the piezoelectric rubber bearing, the technical condition of the bridge main beam is quickly and intelligently assessed according to the assessment standards.

[0013] Preferably, the S1 comprises the following steps:

[0014] Collect initial disease data of the main beam of a simply supported beam bridge, including cracks, spalling, material aging, etc.

[0015] Correct the initial stiffness of the main beam according to the initial state data of the main beam;

[0016] The initial potential value of the piezoelectric rubber bearing without external load is recorded as a benchmark for subsequent analysis.

[0017] Preferably, S2 comprises the following steps:

[0018] Determine the overall or local nature of the disease and the corresponding degree of disease according to the main beam disease condition;

[0019] According to the decrease in bridge bearing capacity caused by the disease, the degradation of the main beam stiffness is calculated;

[0020] The trend of electric potential change at the support is obtained through the stiffness degradation to reflect the impact of the disease on the overall structure of the bridge.

[0021] Preferably, S3 comprises the following steps:

[0022] Monitor the potential change of the piezoelectric sheet embedded in the support in real time according to the change of the main beam stiffness;

[0023] Record the potential changes of the piezoelectric film at the support when the overall and local stiffness of the main beam change respectively;

[0024] When the stiffness of the main beam changes due to defects such as material aging or cracks, calculate the rotation angle at the support and use the following formula to obtain the potential change value:

[0025]

[0026] Where V is the potential change, P is the pressure on the piezoelectric plate at the support, and d 33 is the piezoelectric constant of the piezoelectric material, and A is the area of ​​the piezoelectric sheet.

[0027] Preferably, S4 comprises the following steps:

[0028] According to the relevant provisions on bearing capacity in the Highway Bridge and Culvert Maintenance Code (JTG5120-2021), a decrease of 0 to 25% in the overall stiffness of the bridge is set as the range for assessing the technical condition of the bridge;

[0029] The location and extent of the main beam defect can be estimated based on the correlation between the rotation angle change and the electric potential change at the support.

[0030] Preferably, S5 comprises the following steps:

[0031] The technical condition of bridges is divided into five levels, namely, Class 1 (intact), Class 2 (good), Class 3 (average), Class 4 (poor), and Class 5 (dangerous), and the stiffness degradation rates are 0-3%, 3-5%, 5-10%, 10-25%, and greater than 25% respectively;

[0032] The threshold range of the potential change at the support is defined so that the potential change rates corresponding to different stiffness degradation rates are: [0, 3.1]%, [3.1, 5.3]%, [5.3, 11.1]%, [11.1, 33.3]% and >33.3%.

[0033] Preferably, S6 comprises the following steps:

[0034] Collect the real-time electrical potential change data of the bridge and store it in the database;

[0035] Based on the real-time monitored electric potential change data, the current health level of the bridge is determined according to the constructed technical condition assessment standards;

[0036] If the potential change exceeds the set threshold, the alarm system will be triggered, prompting management personnel to conduct further inspections of the bridge.

[0037] Preferably, the method further includes analyzing the historical trend of bridge conditions based on data storage, and predicting the development trend of main beam defects by comparing the current bridge state with the historical state.

[0038] Preferably, a random forest model is used to train the historical electrical potential data of the bridge to predict the future technical condition of the bridge main beam.

[0039] Preferably, the method further includes visually displaying the bridge assessment results, displaying the bridge health score and technical condition grade in real time, and generating a bridge technical condition assessment report.

[0040] The invention provides a method for evaluating the technical condition of a main beam of a simply supported beam bridge based on a piezoelectric rubber bearing.

[0041] It has the following beneficial effects:

[0042] 1. The present invention monitors the potential changes of the bridge main beam in real time through piezoelectric rubber bearings, constructs a quantitative relationship between the stiffness degradation rate and the potential change rate, realizes a rapid and accurate assessment of the technical condition of the bridge, facilitates real-time monitoring of the health status of the bridge, and effectively improves the reliability and timeliness of bridge safety management.

[0043] 2. By introducing trend analysis of historical data and random forest models, the present invention can accurately predict the development trend of bridge main beam diseases, support proactive maintenance of bridges, effectively extend the service life of bridges, reduce management and maintenance costs, and ensure long-term stable operation of bridges.

[0044] 3. The present invention provides managers with an intuitive and convenient means of bridge health management through the visualization of health scores and technical condition levels and the automatically generated technical condition assessment report, making bridge monitoring, analysis, and decision-making more efficient and providing scientific support for bridge maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 The present invention is a flow chart of the method. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the specification of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] Please refer to the attached Figure 1 The embodiment of the present invention provides a method for evaluating the technical condition of a main beam of a simply supported beam bridge based on a piezoelectric rubber bearing, the method comprising the following steps:

[0048] S1. Data collection: Collect the initial state data of the main beam of the simply supported beam bridge, record the initial stiffness of the main beam and the potential value at the support. When using, first install the piezoelectric rubber bearing sensor, embed the piezoelectric sheet at the support of the simply supported beam bridge, and record the initial stiffness of the main beam and the potential value at the support. The stiffness data can be obtained through the design parameters of the bridge, usually based on the elastic modulus and section inertia moment of the bridge material. The piezoelectric rubber bearing will produce potential changes under pressure. Recording the initial potential value can provide a stable reference point for subsequent data, thereby ensuring that the data of the bridge is consistent in disease analysis and technical evaluation, which helps to improve the accuracy and reliability of detection;

[0049] S2. Analysis of the impact of defects: By reversely analyzing the changes in the bearing capacity caused by the overall or local defects of the main beam of a simply supported beam bridge, the change value of the main beam stiffness degradation is obtained. By simulating the specific impact of the defect on the stiffness, the bearing capacity of the bridge can be accurately predicted at an early stage, ensuring the reliability of defect detection and the scientific nature of the evaluation;

[0050] S3. Detection of potential changes: Based on the change in the rotation angle of the bridge support caused by the change in the main beam stiffness, the potential change of the piezoelectric sheet embedded in the support is detected in real time. By detecting the potential change in real time, the mechanical state change of the bridge can be quickly captured, and an immediate response to the technical condition of the main beam can be achieved, thereby improving the sensitivity and accuracy of bridge disease monitoring;

[0051] S4. Status assessment: Based on the bearing capacity standard for the technical condition level of bridges in the Highway Bridge and Culvert Maintenance Code (JTG5120-2021), analyze the potential change law of the pre-embedded piezoelectric plates in the bearings, judge the technical condition level of the bridge, and divide the technical condition of the bridge into different levels, so that management personnel can perform preventive maintenance according to the level distribution to ensure the safety and stability of the bridge structure;

[0052] S5. Construction of technical condition assessment standard: According to the relationship between the main beam stiffness degradation rate and the potential change rate, a quantitative assessment standard for the technical condition of the bridge is constructed. In this step, the quantitative assessment standard for the technical condition of the bridge is established in combination with the relationship between the stiffness degradation of the main beam of the bridge and the potential change. The quantitative standard associates the stiffness degradation rate with the potential change rate to form a one-to-one technical condition mapping relationship, which can not only improve the consistency and accuracy of the condition assessment, but also provide a quantitative basis for the health management of the bridge, facilitating the decision-making of maintenance management;

[0053] S6. Implementation of intelligent assessment: Utilize the potential change data of the piezoelectric rubber bearings to conduct an intelligent and rapid assessment of the technical condition of the bridge main beam according to the assessment standards. This step utilizes the real-time collected potential data of the piezoelectric rubber bearings, combined with the established assessment standard table, to conduct an intelligent assessment of the technical condition of the bridge main beam. With the help of data collected in real time by sensors and the intelligent assessment system, the bridge condition can be assessed quickly and accurately, thereby realizing the intelligent and automated management of the bridge's technical condition, effectively reducing the subjective errors of manual inspection, and providing a more efficient means of disease identification and safety monitoring.

[0054] Please refer to the attached Figure 1 In a preferred embodiment of the present invention, S1 comprises the following steps:

[0055] Collect the initial disease data of the main beam of the simply supported beam bridge, including cracks, spalling, material aging and other data of the main beam. The initial disease of the bridge structure will affect the stiffness and overall bearing capacity of the main beam. Defects such as cracks and spalling reduce the local stiffness of the structure, while material aging affects the overall structural performance. Therefore, by comprehensively recording the disease condition of the main beam, it provides an important reference for subsequent stiffness correction and technical condition assessment, thereby ensuring that the bridge assessment process can cover all potential initial diseases, which helps to improve the accuracy and reliability of the technical condition assessment. At the same time, detailed disease data can also help establish a health record for the bridge, facilitating subsequent disease management and repair decisions;

[0056] The initial stiffness of the main beam is corrected according to the initial state data of the main beam. First, the influence of defects such as cracks and spalling on the structural stiffness is quantified through a mechanical analysis model (such as a stiffness reduction model based on material mechanics). Specifically, the stiffness reduction coefficient d caused by the initial defect can be substituted into the following formula to correct the initial stiffness:

[0057] K initial =K0·(1-d)

[0058] Where K initial is the corrected initial stiffness;

[0059] K0 is the initial stiffness during design;

[0060] d is the stiffness reduction coefficient, which is determined according to the specific conditions of the disease. Correcting the initial stiffness can reduce the deviation between the design data and the actual situation, thereby improving the accuracy of technical condition assessment and avoiding misjudgment caused by the deviation of the initial stiffness. At the same time, the corrected initial stiffness provides a more accurate comparison benchmark for subsequent real-time monitoring data;

[0061] The initial potential value of the piezoelectric rubber bearing without external load is recorded as a benchmark for subsequent analysis. The piezoelectric rubber bearing generates potential under external load. Therefore, recording the initial potential value under no-load conditions can provide a benchmark for subsequent potential change monitoring. The potential change directly reflects the force change at the bearing, which is a reflection of the change in bridge stiffness and bearing capacity. It helps to detect early degradation of the structure in a timely manner and improve the sensitivity and effectiveness of disease monitoring.

[0062] Please refer to the attached Figure 1 In a preferred embodiment of the present invention, S2 comprises the following steps:

[0063] Determine the overall or local nature of the disease and the corresponding degree of disease according to the main beam disease condition. By comprehensively and accurately determining the nature and degree of the disease, the calculation basis of stiffness degradation is more scientific, laying an accurate foundation for subsequent technical condition assessment. Detailed disease classification can improve the sensitivity of the assessment, effectively reflect the distribution of bridge diseases and their impact range, thereby ensuring the reliability of the assessment results;

[0064] According to the decrease in the bearing capacity of the bridge caused by the disease, the degradation of the main beam stiffness is calculated. Factors such as material aging and crack expansion caused by the disease will reduce the stiffness of the bridge. The stiffness degradation can be accurately reflected by correcting parameters such as the elastic modulus and the area of ​​the disease, thereby quantifying the impact of the disease as the degradation of the stiffness. By distinguishing between overall and local stiffness degradation, the degree of influence of different types of diseases can be more accurately reflected, providing a scientific reference for the technical condition assessment of the bridge and ensuring the accuracy of the assessment results;

[0065] The trend of the potential change at the support is obtained through the stiffness degradation to reflect the impact of the disease on the overall structure of the bridge. The potential change at the support directly reflects the impact of the stiffness degradation of the bridge on the bearing state of the bridge. Stiffness degradation causes the force at the bridge support to change, which in turn produces potential fluctuations. Therefore, when subtle diseases occur in the bridge structure, they can be discovered in time, ensuring the real-time and accuracy of the bridge technical condition assessment.

[0066] Please refer to the attached Figure 1 In a preferred embodiment of the present invention, S3 includes the following steps:

[0067] According to the change of main beam stiffness, the potential change of the embedded piezoelectric sheet in the support is monitored in real time. The decrease of stiffness of the bridge structure will change the mechanical state of the main beam and the support. The piezoelectric sheet at the support will produce different potential signals under stress change. Real-time monitoring of potential changes can reflect the change of main beam stiffness through potential fluctuations, and realize sensitive monitoring of the technical condition of the bridge. This method effectively improves the timeliness of technical condition assessment, reduces the shortcomings of relying on regular manual inspections, and provides timely technical support for bridge safety monitoring;

[0068] The potential changes of the piezoelectric film at the support are recorded separately when the overall and local stiffness of the main beam change. The overall disease and local disease have different influences on the stiffness. The overall disease will cause a slow and continuous change in the potential of the support, while the local disease will cause stress fluctuations in the local area, resulting in intermittent fluctuations in the potential. Therefore, by recording the potential changes of the overall and local diseases separately, different types of diseases can be effectively identified;

[0069] When the stiffness of the main beam changes due to defects such as material aging or cracks, calculate the rotation angle at the support and use the following formula to obtain the potential change value:

[0070]

[0071] Where V is the potential change, P is the pressure on the piezoelectric plate at the support, and d 33 is the piezoelectric constant of the piezoelectric material, A is the area of ​​the piezoelectric sheet, and the combination of the calculation of the support angle and the potential change formula enables the system to accurately and effectively quantify the degree of girder stiffness degradation, thereby providing an intuitive health status indicator. The accurate calculation of the potential change value provides reliable quantitative data support for bridge status assessment, improving the accuracy and sensitivity of the system during the assessment process.

[0072] Please refer to the attached Figure 1 In a preferred embodiment of the present invention, S4 comprises the following steps:

[0073] According to the relevant provisions on bearing capacity in the Highway Bridge and Culvert Maintenance Specification (JTG5120-2021), the overall stiffness reduction of the bridge is set at 0-25% as the range for assessing the bridge's technical condition. This grading method based on stiffness degradation provides an objective quantitative standard for technical condition assessment, improving the accuracy and consistency of the assessment. At the same time, according to the set standards of the specification, it is also convenient for bridge management personnel to carry out planned maintenance based on the grade distribution, effectively improving the scientificity and economy of bridge maintenance management;

[0074] According to the correlation between the change in the rotation angle and the change in the electric potential at the support, the location and degree of the main beam disease are estimated. The change in the rotation angle of the support is proportional to the decrease in the stiffness of the main beam, and the change in the rotation angle will cause the change in the electric potential at the support. Therefore, the electric potential data at the support can directly reflect the change in the stiffness of the main beam and the force distribution, thereby inferring the location and degree of the disease. At the same time, through the combined change in rotation angle and electric potential, the accurate estimation of the location and degree of the disease is achieved, which not only improves the sensitivity of disease detection, but also makes the results of technical condition assessment more valuable for reference.

[0075] Please refer to the attached Figure 1 In a preferred embodiment of the present invention, S5 comprises the following steps:

[0076] The technical condition of bridges is divided into five levels, namely Class 1 (intact), Class 2 (good), Class 3 (average), Class 4 (poor), and Class 5 (dangerous). The stiffness degradation rates are 0-3%, 3-5%, 5-10%, 10-25%, and greater than 25%, respectively. The grade standard established by the stiffness degradation rate provides a clear quantitative indicator for the technical condition assessment of bridges, which helps to accurately and operationally classify the condition of bridges. At the same time, the classification level enables bridge managers to quickly identify bridges at different condition levels, facilitate the formulation of maintenance strategies, and thus ensure the safe operation of bridges under different disease conditions;

[0077] The threshold range of potential change at the support is defined so that the potential change rates corresponding to different stiffness degradation rates are: [0, 3.1]%, [3.1, 5.3]%, [5.3, 11.1]%, [11.1, 33.3]% and >33.3%. The threshold definition of the potential change rate makes the technical condition assessment more convenient and automated, which not only reduces the workload of manual inspection, but also enables continuous tracking of bridge conditions through real-time monitoring. The quantitative standard of the potential change rate provides a scientific basis for the technical condition assessment, making the assessment process more operational and timely.

[0078] Please refer to the attached Figure 1 In a preferred embodiment of the present invention, S6 comprises the following steps:

[0079] Collect the real-time electrical potential change data of the bridge and store it in the database. By collecting and storing the electrical potential data in real time, continuous monitoring of the stress changes of the bridge can be achieved. The electrical potential changes reflect the stress conditions of the supports and the stiffness changes of the main beams. Therefore, storing the electrical potential data can provide a complete record of the health status of the bridge, providing a real-time basis for technical status assessment.

[0080] Based on the real-time monitored potential change data, the current health level of the bridge is judged according to the established technical condition assessment standard. The health level and potential change rate R in the assessment standard table are V The system will match the current potential change rate with the interval range in the standard table to obtain the health level of the bridge. For example, if the current detected potential change rate is 7%, the system will automatically match it to the health level of Class 3 (General).

[0081] The specific calculation formula for determining the health level is:

[0082]

[0083] Among them, R Vis the rate of change of potential; V(t) is the current potential value; V0 is the initial potential value (reference value). The rate of change of potential directly reflects the stiffness degradation of the bridge. Through the pre-set technical condition assessment standard, the current potential change data can be quickly and accurately converted into the bridge health level, thereby realizing real-time and automatic assessment of the technical condition and improving the efficiency and objectivity of the assessment. The real-time display of the bridge health level enables management personnel to have a clear and intuitive understanding of the bridge status, facilitating timely adoption of corresponding management measures;

[0084] If the potential change exceeds the set threshold, the alarm system will be triggered, prompting the management personnel to conduct further inspections of the bridge. When the potential change exceeds the safety threshold, the stiffness degradation of the bridge main beam has reached a level that may affect the structural safety. Therefore, the alarm system can notify the management personnel in advance to conduct further inspections to prevent potential structural damage or accidents, thereby reducing the possibility of manual inspections and misjudgments, and providing safe and reliable protection for bridge health management.

[0085] Please refer to the attached Figure 1 In a preferred embodiment of the present invention, the method further includes historical trend analysis of bridge conditions based on data storage. By comparing the current bridge state with the historical state, the development trend of the main beam disease is predicted. The accumulation of historical data makes the assessment of the bridge technical condition not only limited to the current state, but also can analyze its change trend over time, which is helpful for comprehensive and long-term analysis of the development trajectory of bridge diseases and provides strong data support for preventive maintenance of bridges.

[0086] Please refer to the attached Figure 1 In a preferred embodiment of the present invention, a random forest model is used to train the historical electrical potential data of the bridge to predict the future technical status of the bridge girder. The machine learning model has high requirements for the accuracy and consistency of the data. Feature extraction and data cleaning can ensure the quality of the input data, thereby improving the prediction effect of the model. Through data cleaning and feature extraction, the model can extract the key variables of the bridge health status, which helps to improve the accuracy and reliability of the prediction. At the same time, normalization processing can accelerate the training process and improve the convergence effect of the model.

[0087] Please refer to the attached Figure 1 In a preferred embodiment of the present invention, the method further includes visually displaying the bridge assessment results, displaying the bridge health score and technical condition level in real time, and generating a bridge technical condition assessment report. The calculation formula of the health score is as follows:

[0088] S=100-R K ×100

[0089] Among them, S is the bridge health score, with a full score of 100 points;

[0090] R K is the stiffness degradation rate of the bridge girder.

[0091] The scoring rules are set as follows: when S≥90, the bridge is in good condition; 80-89 points indicate good condition; 60-79 points indicate fair condition; 40-59 points indicate poor condition; and less than 40 points indicate that the bridge is in a dangerous state. The technical condition level can be automatically displayed on the system interface based on the threshold range of the health score and the potential change rate, and the current bridge health status can be intuitively displayed in the form of charts or indicator lights. Data visualization makes the bridge assessment results clear at a glance, improves the efficiency of information transmission, and helps managers to quickly and accurately grasp the bridge status. The graphical display method reduces the difficulty of management, making the health monitoring and risk warning of the bridge more timely and intuitive. At the same time, the technical condition assessment report provides managers with a complete bridge health file, which helps to formulate and implement bridge maintenance plans. The regular generation of reports can be used for long-term monitoring of bridge health status, providing data support and scientific basis for bridge decision-making management.

[0092] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for evaluating the technical condition of a main beam of a simply supported beam bridge based on piezoelectric rubber bearings, characterized in that: The method comprises the following steps: S1. Data collection: Collect the initial state data of the main beam of the simply supported beam bridge, and record the initial stiffness of the main beam and the potential value at the support; S2. Analysis of the impact of damage: by reversely analyzing the change in the bearing capacity caused by the overall or local damage of the main beam of the simply supported beam bridge, the change value of the main beam stiffness degradation is obtained; S3, potential change detection: according to the change of the rotation angle at the bridge support caused by the change of the main beam stiffness, the potential change of the piezoelectric sheet embedded in the support is detected in real time; S4. Status assessment: Based on the load-bearing capacity standard for the technical condition level of bridges in the Highway Bridge and Culvert Maintenance Specifications (JTG5120-2021), analyze the potential change law of the embedded piezoelectric plates in the bearings to determine the technical condition level of the bridge; S5. Construction of technical condition assessment standard: Based on the relationship between the main beam stiffness degradation rate and the potential change rate, a quantitative assessment standard for the technical condition of the bridge is constructed; S6. Implementation of intelligent assessment: Using the potential change data of the piezoelectric rubber bearing, the technical condition of the bridge main beam is quickly and intelligently assessed according to the assessment standards.

2. The method for evaluating the technical condition of a main beam of a simply supported beam bridge based on a piezoelectric rubber bearing according to claim 1 is characterized in that: The S1 comprises the following steps: Collect initial disease data of the main beam of a simply supported beam bridge, including cracks, spalling, material aging, etc. Correct the initial stiffness of the main beam according to the initial state data of the main beam; The initial potential value of the piezoelectric rubber bearing without external load is recorded as a benchmark for subsequent analysis.

3. The method for evaluating the technical condition of a main beam of a simply supported beam bridge based on a piezoelectric rubber bearing according to claim 1 is characterized in that: The S2 comprises the following steps: Determine the overall or local nature of the disease and the corresponding degree of disease according to the main beam disease condition; According to the decrease in bridge bearing capacity caused by the disease, the degradation of the main beam stiffness is calculated; The trend of electric potential change at the support is obtained through the stiffness degradation to reflect the impact of the disease on the overall structure of the bridge.

4. The method for evaluating the technical condition of a main beam of a simply supported beam bridge based on a piezoelectric rubber bearing according to claim 1, characterized in that: The S3 comprises the following steps: Monitor the potential change of the piezoelectric sheet embedded in the support in real time according to the change of the main beam stiffness; Record the potential changes of the piezoelectric film at the support when the overall and local stiffness of the main beam change respectively; When the stiffness of the main beam changes due to defects such as material aging or cracks, calculate the rotation angle at the support and use the following formula to obtain the potential change value: Where V is the potential change, P is the pressure on the piezoelectric plate at the support, and d 33 is the piezoelectric constant of the piezoelectric material, and A is the area of ​​the piezoelectric sheet.

5. The method for evaluating the technical condition of a main beam of a simply supported beam bridge based on a piezoelectric rubber bearing according to claim 1 is characterized in that: The S4 comprises the following steps: According to the relevant provisions on bearing capacity in the Highway Bridge and Culvert Maintenance Code (JTG5120-2021), a decrease of 0 to 25% in the overall stiffness of the bridge is set as the range for assessing the technical condition of the bridge; The location and extent of the main beam defect can be estimated based on the correlation between the rotation angle change and the electric potential change at the support.

6. The method for evaluating the technical condition of a main beam of a simply supported beam bridge based on a piezoelectric rubber bearing according to claim 1, characterized in that: The S5 comprises the following steps: The technical condition of bridges is divided into five levels, namely, Class 1 (intact), Class 2 (good), Class 3 (average), Class 4 (poor), and Class 5 (dangerous), and the stiffness degradation rates are 0-3%, 3-5%, 5-10%, 10-25%, and greater than 25% respectively; The threshold range of the potential change at the support is defined so that the potential change rates corresponding to different stiffness degradation rates are: [0, 3.1]%, [3.1, 5.3]%, [5.3, 11.1]%, [11.1, 33.3]% and >33.3%.

7. The method for evaluating the technical condition of a main beam of a simply supported beam bridge based on a piezoelectric rubber bearing according to claim 1, characterized in that: The S6 comprises the following steps: Collect the real-time electrical potential change data of the bridge and store it in the database; Based on the real-time monitored electric potential change data, the current health level of the bridge is determined according to the constructed technical condition assessment standards; If the potential change exceeds the set threshold, the alarm system will be triggered, prompting management personnel to conduct further inspections of the bridge.

8. The method for evaluating the technical condition of a main beam of a simply supported beam bridge based on a piezoelectric rubber bearing according to claim 1, characterized in that: The method further includes historical trend analysis of bridge conditions based on data storage, and prediction of the development trend of main beam diseases is achieved by comparing the current bridge status with the historical status.

9. The method for evaluating the technical condition of the main beam of a simply supported beam bridge based on piezoelectric rubber bearings according to claim 8 is characterized in that: The random forest model is used to train the historical electrical potential data of the bridge to predict the future technical condition of the bridge main beam.

10. The method for evaluating the technical condition of a main beam of a simply supported beam bridge based on a piezoelectric rubber bearing according to claim 1, characterized in that: The method further includes visually displaying the bridge assessment results, displaying the bridge health score and technical condition grade in real time, and generating a bridge technical condition assessment report.

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