Method for testing dead load stress of concrete bridge

Abstract

The invention discloses a concrete bridge dead load stress testing method, and belongs to the technical field of bridge detection. A data acquisition module in the concrete bridge acquires stress and temperature data of the concrete bridge at set time intervals; stress and temperature data of the concrete bridge are collected and transmitted to the data analysis module for analysis through the control module; the data analysis module obtains a stress value sigma nm, a dependent variable sigma nm and an average stress sigma A of the concrete bridge according to the stress and temperature data; the data comparison module judges whether the stress value sigma nm, the dependent variable sigma nm and the average stress sigma A exceed set threshold values or not; and when one of the stress value sigma nm, the dependent variable sigma nm or the average stress sigma A exceeds a set threshold value, the monitoring platform controls the early warning module to give an early warning. Through the arrangement of the plurality of acquisition modules, the stress and related data of the concrete bridge can be tested, and the quality monitoring of the bridge is realized.

Description

Technical Field

[0001] The present application relates to the technical field of bridge detection, and more specifically, to a method for testing constant load stress of a concrete bridge. Background Art

[0002] The dead load stress of concrete bridges is an important parameter in bridge design, which reflects the maximum normal stress level of the bridge structure under the design load. The magnitude of the dead load stress directly affects the service life and safety of concrete, because when the stress exceeds the strength of concrete, concrete will be damaged. The determination of the dead load stress is a complex process that requires consideration of many factors, such as design load, material properties, geometric dimensions, etc. Therefore, accurately calculating the dead load stress and conducting sufficient verification are crucial to ensure the safety and service life of concrete bridges.

[0003] After a concrete bridge is built, the constant load internal force and stress generated by the structure's own load will change as the service time increases. The changes in constant load internal force and stress will threaten the safety of the bridge.

[0004] The document with the prior art publication number CN110955928A provides a constant load stress test system and method for a concrete bridge, and an information data processing terminal. Through the bridge prestress detection module, during the effective prestressing construction process of the bridge, the tensioning strength and tensioning displacement data can be collected in real time and sent to the test platform terminal for data analysis. The test platform terminal establishes the tensioning strength and tensioning displacement and the real-time relationship between the two through real-time measurement data, intelligently controls the size and uniformity of the effective prestress, and improves the accuracy of bridge prestressing detection; at the same time, through the analysis module based on the measured traffic data of the bridge to be analyzed, using the data simulation method, the stress cycle data of the bridge to be analyzed is obtained, the theory is scientific, the analysis results are scientific and reliable, the applicability is strong, and it has important engineering significance.

[0005] Although the above-mentioned prior art solutions can achieve the relevant beneficial effects through the structure of the prior art, in the stress monitoring, the temperature and the expansion parameters of the concrete will affect the monitoring results. Therefore, how to improve the accuracy of the stress test results is particularly important. In view of this, we propose a method for testing the constant load stress of concrete bridges. Summary of the invention

[0006] 1. Technical issues to be solved

[0007] The purpose of this application is to provide a method for testing the constant load stress of a concrete bridge, which solves the technical problem in the prior art that the stress of the concrete bridge measured only by a detector is deviated from the actual stress, and achieves the technical effect of improving the accuracy of the test results of the concrete bridge stress.

[0008] 2. Technical solution

[0009] The embodiment of the present application provides a method for testing the constant load stress of a concrete bridge, wherein a data acquisition module is pre-buried in the concrete bridge, and the data acquisition module collects stress and temperature data of the concrete bridge at set intervals;

[0010] The stress and temperature data of the concrete bridge are collected and transmitted to the data analysis module through the control module for analysis;

[0011] The data analysis module obtains the stress value σnm, strain △σnm and average stress σA of the concrete bridge based on the stress and temperature data;

[0012] The data comparison module determines whether the stress value σnm, the strain value △σnm and the average stress σA exceed the set threshold;

[0013] When one of the stress value σnm, strain value △σnm or average stress σA exceeds the set threshold, the monitoring platform controls the early warning module to issue an early warning.

[0014] By adopting the above technical solution and setting up several acquisition modules, it is possible to test the stress and related data of the concrete bridge and realize the quality monitoring of the bridge.

[0015] As an optional solution of the technical solution of this application document, the acquisition module monitors the stress and temperature data of the concrete bridge through multi-directional strain gauges and temperature sensors, and each multi-directional strain gauge corresponds to a temperature sensor.

[0016] By adopting the above technical solution, several groups of multi-directional strain gauges are embedded in the bridge concrete, and several multi-directional strain gauges are evenly distributed. Each multi-directional strain gauge is composed of several strain gauges. The multi-directional strain gauge setting can simultaneously measure strain changes in multiple directions, thereby improving the precision and accuracy of measurement. The multi-directional strain gauge adopts multiple sensor elements, and each sensor element has an independent reading function. Therefore, when a sensor element fails, the remaining sensors can still work normally, ensuring the continuity and reliability of measurement. The multiple sensor elements in the multi-directional strain gauge can share the stress load together, reduce the risk of single point failure, and improve the durability of the entire structure. The multi-directional strain gauge is simple and flexible to install and easy to maintain.

[0017] As an optional solution of the technical solution of the present application document, each measuring direction of each multi-directional strain gauge has an independent number. When an early warning is issued, the database will send the stored position information of the multi-directional strain gauge with the corresponding number to the monitoring platform.

[0018] By adopting the above technical scheme, according to different installation positions, several groups of multi-directional strain gauges are numbered and each multi-directional strain gauge is numbered according to different monitoring directions, and several stress values ​​σnm are obtained, where nm in σnm is a combination of numbers of different position numbers and different stress detection directions, and the position information is the installation position of the multi-directional strain gauge relative to the concrete bridge, which is convenient for finding when the multi-directional strain gauge is maintained in the later stage, reducing the difficulty of maintenance. For example, the stress value in the Z direction on the first multi-directional strain gauge is expressed as σ1Z, the stress value in the z direction on the second multi-directional strain gauge is expressed as σ2Z, the stress value in the positive x direction on the second multi-directional strain gauge can be expressed as σ2X+, and the strain gauge stress value in the XOZ plane on the second multi-directional strain gauge is expressed as σ2XOZ+ if X is the positive direction, and is expressed as σ2XOY- if the plane is the negative direction of the X axis, thereby realizing the label classification of each strain gauge and reducing the difficulty of resolving the pressure data detected by the strain gauge.

[0019] As an optional solution to the technical solution of this application document, after the construction of the concrete bridge is completed, the first set of data measured by the multi-directional strain gauge is the initial stress data σnm0, which also serves as the measurement reference value of the multi-directional strain gauge. The initial temperature data T0 measured by the temperature sensor also serves as the temperature measurement reference value.

[0020] As an optional solution of the technical solution of this application document, the specific calculation method of the strain △σnm of the concrete bridge is:

[0021] △σnm=K(σnm-σnm0)+(ba)(Tnm-T0);

[0022] Among them, K is the measurement sensitivity of the strain gauge, b is the temperature correction coefficient of the strain gauge, a is the linear expansion coefficient of concrete, and Tnm is the temperature value monitored in real time by the temperature sensor at the corresponding multi-directional strain gauge.

[0023] By adopting the above technical solution and detecting the strain △σnm of the concrete bridge, it can be analyzed that the constant load stress of the concrete bridge changes under the influence of factors such as temperature change and concrete shrinkage and expansion, so that the concrete bridge can be regularly inspected and evaluated to ensure its safety.

[0024] As an optional solution of the technical solution of the present application document, the average stress σA of different nodes of the multi-directional strain gauge in the same direction is Σσnm / n; Σσnm is the sum of stress value data collected by several multi-directional strain gauges in the same direction, and n is the number of multi-directional strain gauges.

[0025] By adopting the above technical solution, the average stress σA of different nodes of the multi-directional strain gauges in the same direction is calculated by the ratio of the sum of the stress value data collected by several multi-directional strain gauges in the same direction and the number of multi-directional strain gauges. The σA data can be used to realize real-time monitoring of the overall stress condition of the concrete bridge.

[0026] As an optional solution of the technical solution of the present application document, when acquiring stress data, the multi-directional strain gauge acquires multiple continuous strain data at the same time node and in the same direction to form a stress data group. The stress data group is transmitted to the data analysis module through the control module, and the multiple continuous strain data are averaged using the median filtering method to obtain the final stress data of the final node at the same time and in the same direction.

[0027] By adopting the above technical solution, multiple continuous strain data are obtained and screened at the same time node and in the same direction, thereby reducing the impact of abnormal data on the test and improving the reliability of the data.

[0028] As an optional solution of the technical solution of this application document, after the data analysis module obtains the stress data, strain data and average stress data, it generates a corresponding curve graph and transmits it to the monitoring platform.

[0029] By adopting the above technical solution, the monitoring platform monitors the data in real time, making it easy to intuitively view the monitoring data from the monitoring platform.

[0030] As an optional solution of the technical solution of this application document, the specific way in which the early warning module triggers the early warning is:

[0031] After the data analysis module analyzes the corresponding stress, strain and average stress data, it transmits them to the data comparison module. The data comparison module retrieves the preset stress threshold, strain threshold and average stress threshold from the database and compares them with the acquired stress, strain and average stress data respectively; when the stress data value exceeds the corresponding threshold, the data analysis module transmits the number and location information of the corresponding multi-directional strain gauge to the monitoring platform, and the monitoring platform sends a warning signal to the warning module, and the warning module makes a corresponding warning according to the warning signal.

[0032] By adopting the above technical solution, the data comparison module retrieves the preset stress threshold, strain threshold and average stress threshold from the database and compares them with the acquired stress, strain and average stress data respectively, so as to judge the relationship between the stress and safety stress of the concrete bridge. When the stress data value exceeds the corresponding threshold, it means that the safety stress is exceeded. At this time, there may be potential risks for the passage of the concrete bridge. At the same time, it can be discovered and warned in advance, so as to eliminate the hidden dangers and improve the safety of the passage of the concrete bridge.

[0033] As an optional solution of the technical solution of this application document, the data generated during the concrete bridge test are stored in the database.

[0034] By adopting the above technical solution, the data obtained during the stress test are stored in the database, which is convenient for later maintenance and retrieval.

[0035] 3. Beneficial effects

[0036] One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:

[0037] 1. This application can test the stress and related data of concrete bridges and monitor the quality of bridges by setting up several acquisition modules. During stress analysis and calculation, by adding concrete expansion calibration coefficient, strain gauge measurement sensitivity coefficient and strain gauge temperature correction coefficient, the influence of factors such as different temperatures at different times on the test can be effectively calibrated, thereby improving the accuracy of the test.

[0038] 2. The present application adopts a multi-directional strain gauge setting to simultaneously measure strain changes in multiple directions, thereby improving the measurement precision and accuracy. The multi-directional strain gauge adopts multiple sensor elements, each of which has an independent reading function. Therefore, when a sensor element fails, the remaining sensors can still work normally, ensuring the continuity and reliability of the measurement. The multiple sensor elements in the multi-directional strain gauge can share the stress load together, reduce the risk of single point failure, and improve the durability of the entire structure.

[0039] 3. In this application, according to different installation positions, several groups of multi-directional strain gauges are numbered and each multi-directional strain gauge is numbered according to different monitoring directions to obtain several stress values ​​σnm, where nm in σnm is a combination of different position numbers and different stress detection directions. The position information is the installation position of the multi-directional strain gauge relative to the concrete bridge. When an early warning occurs, the control platform can quickly obtain the corresponding multi-directional strain gauge position information, which is convenient for locating the multi-directional strain gauge during later maintenance and reduces the difficulty of maintenance.

[0040] 4. This application can detect the strain △σnm of the concrete bridge and analyze that the constant load stress of the concrete bridge changes under the influence of factors such as temperature change, concrete shrinkage and expansion, so as to conduct regular inspection and evaluation of the concrete bridge to ensure its safety.

[0041] 5. This application obtains and screens multiple continuous strain data at the same time node and in the same direction, thereby reducing the impact of abnormal data on the test and improving the reliability of the data. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 A schematic flow chart of a method for testing the constant load stress of a concrete bridge disclosed in a preferred embodiment of the present application;

[0043] Figure 2 This is a schematic structural diagram of a multi-directional strain gauge for a method for testing the constant load stress of a concrete bridge disclosed in a preferred embodiment of the present application.

[0044] Explanation of the numbers in the figure: 1. Data acquisition module; 2. Control module; 3. Data analysis module; 4. Data comparison module; 5. Monitoring platform; 6. Early warning module; 7. Database. DETAILED DESCRIPTION

[0045] The present application is further described in detail below in conjunction with the accompanying drawings.

[0046] Reference Figure 1 The embodiment of the present application discloses a method for testing constant load stress of a concrete bridge, including a data acquisition module 1, a control module 2, a data analysis module 3, a data comparison module 4, a monitoring platform 5, an early warning module 6 and a database 7.

[0047] The data acquisition module 1 is used to collect stress data and temperature data of concrete bridges. Several groups of multi-directional strain gauges are embedded in the concrete of the bridge. Several multi-directional strain gauges are evenly distributed. Each multi-directional strain gauge is composed of several strain gauges. Figure 2 In the XOY plane, the angle between two adjacent strain gauges is 90°, and in the ZOY plane, the angle between two adjacent strain gauges is 45°. Compared with a single strain gauge, the multi-directional strain gauge has the following advantages: the multi-directional strain gauge setting can measure strain changes in multiple directions at the same time, thereby improving the measurement precision and accuracy. The multi-directional strain gauge uses multiple sensing elements, each of which has an independent reading function. Therefore, when a sensing element fails, the remaining sensors can still work normally to ensure the continuity and reliability of the measurement. The multiple sensing elements in the multi-directional strain gauge can share the stress load together, reduce the risk of single-point failure, and improve the durability of the entire structure. The multi-directional strain gauge is simple and flexible to install and easy to maintain.

[0048] According to different installation positions, several groups of multi-directional strain gauges are numbered and each multi-directional strain gauge is numbered according to different monitoring directions, so as to obtain several stress values ​​σnm, where nm in σnm is a combination of numbers of different position numbers and different stress detection directions. For example, the stress value in the Z direction on the first multi-directional strain gauge is expressed as σ1Z, the stress value in the z direction on the second multi-directional strain gauge is expressed as σ2Z, the stress value in the positive x direction on the second multi-directional strain gauge can be expressed as σ2X+, and the strain gauge stress value in the XOZ plane on the second multi-directional strain gauge is expressed as σ2XOZ+ if X is the positive direction, and is expressed as σ2XOY- if the plane is the negative direction of the X-axis, thereby realizing the label classification of each strain gauge and reducing the difficulty of resolving pressure data detected by the strain gauge.

[0049] The serial number and corresponding position information of the multi-directional strain gauge are stored in the database 7. The position information is the installation position of the multi-directional strain gauge relative to the concrete bridge, which is convenient for locating the multi-directional strain gauge during maintenance in the later stage, thus reducing the difficulty of maintenance.

[0050] A group of temperature sensors is also embedded at the locations of several groups of multi-directional strain gauges embedded in the bridge concrete to monitor the concrete temperature at the locations.

[0051] The data acquisition module 1 collects the temperature data and stress data of the concrete bridge every time a preset working time interval is reached. The data acquisition module 1 obtains multiple sets of stress data and corresponding temperature data and transmits them to the control module 2. The control module 2 transmits the multiple sets of stress data and corresponding temperature data to the data analysis module 3 through the wireless network. The data analysis module 3 performs stress analysis and calculation on the obtained data.

[0052] After the concrete bridge is built, the initial stress data σnm0 measured by the multi-directional strain gauge is used as the measurement reference value of the multi-directional strain gauge, where σnZ0 is the constant load stress of the concrete bridge, and the initial temperature data T0 measured by the temperature sensor is used as the temperature measurement reference value to obtain the strain △σnm of the concrete bridge. The formula is:

[0053] △σnm=K(σnm-σnm0)+(ba)(Tnm-T0); wherein K is the measurement sensitivity of the strain gauge, b is the temperature correction coefficient of the strain gauge, a is the linear expansion coefficient of concrete, and Tnm is the temperature value monitored in real time by the temperature sensor at the corresponding stress measurement direction.

[0054] By testing the strain △σnm of concrete bridges, it is possible to analyze how the constant load stress of concrete bridges changes under the influence of factors such as temperature changes and concrete shrinkage and expansion, so that concrete bridges can be regularly tested and evaluated to ensure their safety.

[0055] The average stress of different nodes in the same direction is σA = Σσnm / n; that is, the ratio of the sum of the stress value data collected by several multi-directional strain gauges in the same direction to the number of multi-directional strain gauges. The σA data can be used to monitor the overall stress of the concrete bridge in real time.

[0056] In order to further improve the accuracy of the collected data, the multi-directional strain gauge obtains the stress data group at the same time node and in the same direction when acquiring the stress data. When the stress data group is transmitted to the data analysis module 3 via the control module 2, the median filtering method is used to average multiple continuous strain data and then process them to obtain the final stress data of the node at the same time and in the same direction, thereby reducing the impact of abnormal data on the test and improving the reliability of the data.

[0057] After the data analysis module 3 obtains the stress data, strain data and average stress data, it can generate corresponding curve graphs, such as a stress change curve graph (the vertical axis is the stress change, and the horizontal axis is time), etc. The curve graph is transmitted to the monitoring platform 5 for data monitoring, so that the monitoring data can be viewed intuitively from the monitoring platform 5.

[0058] After the data analysis module 3 analyzes the corresponding stress, strain and average stress data, it is transmitted to the data comparison module 4. The data comparison module 4 retrieves the preset stress threshold, strain threshold and average stress threshold from the database 7 and compares them with the acquired stress, strain and average stress data respectively. When the time value exceeds the threshold, the data analysis module 3 transmits the number and position information of the corresponding multi-directional strain gauge to the monitoring platform 5. The monitoring platform 5 sends a warning signal to the warning module 6. The warning module 6 makes a corresponding warning according to the warning signal to remind the management personnel of the concrete bridge, so as to carry out maintenance and inspection in time to ensure the safety of the concrete bridge.

[0059] When the strain data at a certain moment exceeds the set strain data threshold, it means that the bridge structure of the concrete bridge of the corresponding multi-directional strain gauge may be at risk, and the monitoring platform 5 sends the number and location information of the corresponding multi-directional strain gauge to the monitoring platform 5.

[0060] The early warning module 6 issues an early warning, and the preset stress threshold, strain threshold and average stress threshold are all stored in the database 7 .

[0061] The data acquired during the stress test are stored in the database 7 for easy maintenance and retrieval.

Claims

1. A method for testing the constant load stress of a concrete bridge, characterized in that: The data acquisition module (1) is pre-buried in the concrete bridge, and the data acquisition module (1) collects stress and temperature data of the concrete bridge at set intervals; The stress and temperature data of the concrete bridge are collected and transmitted to the data analysis module (3) for analysis via the control module (2); The data analysis module (3) obtains the stress value σnm, strain △σnm and average stress σA of the concrete bridge according to the stress and temperature data; The data comparison module (4) determines whether the stress value σnm, the strain value △σnm and the average stress σA exceed a set threshold; When one of the stress value σnm, the strain value △σnm or the average stress σA exceeds a set threshold, the monitoring platform (5) controls the early warning module (6) to issue an early warning.

2. The method for testing the constant load stress of a concrete bridge according to claim 1, characterized in that: The acquisition module (1) monitors the stress and temperature data of the concrete bridge through multi-directional strain gauges and temperature sensors, and each multi-directional strain gauge corresponds to a temperature sensor.

3. The method for testing the constant load stress of a concrete bridge according to claim 2, characterized in that: Each measuring direction of each multi-directional strain gauge has an independent number. When an early warning is issued, the database sends the stored position information of the multi-directional strain gauge with the corresponding number to the monitoring platform (5).

4. The method for testing the constant load stress of a concrete bridge according to claim 3, characterized in that: After the concrete bridge is built, the first set of data measured by the multi-directional strain gauge is the initial stress data σnm0, which also serves as the measurement reference value of the multi-directional strain gauge. The initial temperature data T0 measured by the temperature sensor also serves as the temperature measurement reference value.

5. The method for testing the constant load stress of a concrete bridge according to claim 4, characterized in that: The specific calculation method of the strain △σnm of the concrete bridge is: △σnm=K(σnm-σnm0)+(ba)(Tnm-T0); Among them, K is the measurement sensitivity of the strain gauge, b is the temperature correction coefficient of the strain gauge, a is the linear expansion coefficient of concrete, and Tnm is the temperature value monitored in real time by the temperature sensor at the corresponding multi-directional strain gauge.

6. The method for testing the constant load stress of a concrete bridge according to claim 5, characterized in that: The average stress σA of different nodes of the multi-directional strain gauge in the same direction is Σσnm / n; Σσnm is the sum of stress value data collected by several multi-directional strain gauges in the same direction, and n is the number of multi-directional strain gauges.

7. The method for testing the constant load stress of a concrete bridge according to claim 1, characterized in that: When acquiring stress data, the multi-directional strain gauge acquires a plurality of continuous strain data at the same time node and in the same direction to form a stress data group. The stress data group is transmitted to the data analysis module (3) via the control module (2), and the plurality of continuous strain data are averaged using the median filtering method to obtain the final stress data of the final node at the same time and in the same direction.

8. The method for testing the constant load stress of a concrete bridge according to claim 1, characterized in that: After the data analysis module (3) acquires the stress data, the strain data and the average stress data, a corresponding curve graph is generated and transmitted to the monitoring platform (5).

9. The method for testing the constant load stress of a concrete bridge according to claim 6, characterized in that: The specific method of triggering the early warning by the early warning module (6) is: After the data analysis module (3) analyzes the corresponding stress, strain and average stress data, the data are transmitted to the data comparison module (4). The data comparison module (4) retrieves the preset stress threshold, strain threshold and average stress threshold from the database (7) and compares them with the acquired stress, strain and average stress data respectively; When the stress data value exceeds the corresponding threshold value, the data analysis module (3) transmits the number and position information of the corresponding multi-directional strain gauge to the monitoring platform (5), the monitoring platform (5) sends a warning signal to the warning module (6), and the warning module (6) makes a corresponding warning according to the warning signal.

10. The method for testing the constant load stress of a concrete bridge according to claim 1, characterized in that: The data generated during the concrete bridge test are stored in the database (7).

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