A method and system for detecting the gap thickness of CFST arch bridge based on cooling excitation intensity

Abstract

The present invention provides a method and system for detecting the void thickness of a CFST arch bridge based on cooling excitation intensity, and relates to the technical field of concrete non-destructive testing, wherein the method comprises the following steps: using a temperature excitation device to perform cooling excitation on a to-be-detected area of ​​a CFST arch bridge specimen to be tested, and simultaneously collecting surface temperature field image data of the to-be-detected area before and after the cooling excitation; processing the surface temperature field image data before and after the cooling excitation to determine whether there is a void area; when there is a void area, determining the area and void thickness of the void area according to the surface temperature field image data before and after the cooling excitation; the present invention realizes infrared quantitative detection of the void thickness of steel tube concrete, which is helpful to more effectively evaluate and ensure the safety and stability of steel tube concrete structures, and is of great significance to engineering safety and structural health monitoring.

Description

Technical Field

[0001] The present invention relates to the technical field of concrete nondestructive testing, and more particularly to a CFST arch bridge void thickness detection method and system based on cooling excitation intensity. Background Art

[0002] At present, concrete de-airing refers to the phenomenon of cavities or voids in concrete structures (such as arch bridges). This may be caused by insufficient or uneven vibration during concrete pouring, or by the failure to completely remove bubbles in the concrete. Concrete de-airing will reduce the density and strength of concrete, and affect the bearing capacity and durability of concrete structures. Therefore, when constructing concrete structures, relevant measures need to be taken to avoid de-airing and de-airing detection should be carried out for steel tube concrete arch bridges or steel tube concrete related structures.

[0003] However, the prior art usually uses the percussion method and the ultrasonic detection method. Although the above methods are accurate and reliable in a small range, they are relatively inefficient when dealing with large-span steel tube concrete arch bridges and similar large structures, and often require technicians to perform high-altitude operations, which increases risks and complexity. In contrast, the infrared detection method, as a type of non-destructive testing technology, shows its unique advantages. It can not only perform remote and non-contact detection, but also effectively cover a large area, greatly improving the efficiency and safety of detection. Although the infrared detection method has potential in detecting void problems in steel tube concrete structures, it currently still faces challenges in accurately quantifying the thickness of the void. The main problems are that the operation is relatively complex, the calculation is huge, and the speed is slow, which makes it difficult to meet the actual detection needs in terms of accuracy and efficiency.

[0004] Therefore, how to provide a hollow thickness detection method that can solve the above problems is an issue that technical personnel in this field need to solve urgently. Summary of the invention

[0005] In view of this, the present invention provides a CFST arch bridge void thickness detection method and system based on cooling excitation intensity, which realizes infrared quantitative detection of steel tube concrete void thickness, helps to more effectively evaluate and ensure the safety and stability of steel tube concrete structures, and is of great significance to engineering safety and structural health monitoring.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A method for detecting the void thickness of a CFST arch bridge based on cooling excitation intensity comprises the following steps:

[0008] Divide the CFST arch bridge specimen to be tested into multiple areas to be tested;

[0009] Using a temperature excitation device to cool the area to be detected, and collecting surface temperature field image data of the area to be detected before and after the cooling excitation;

[0010] Processing the surface temperature field image data before and after applying the cooling excitation to determine whether there is a void area;

[0011] When the void region exists, the area and thickness of the void region are determined according to the surface temperature field image data before and after the cooling excitation, and after the calculation is completed, the remaining areas to be detected are detected in turn.

[0012] Preferably, the specific processing process for obtaining the de-hollowed area includes:

[0013] The surface temperature field image data before and after the cooling excitation is applied is processed using an image recognition algorithm to determine whether there is a void area;

[0014] When there is a missing area, the image segmentation algorithm is used to determine the area of ​​the missing area.

[0015] Preferably, the specific processing process for obtaining the thickness of the hollow area includes:

[0016] According to the judgment result of the de-airing area, the temperature of the de-airing area and the temperature of the non-de-airing area before the cooling excitation are obtained, and at the same time, the temperature of the de-airing area and the temperature of the non-de-airing area after the cooling excitation are obtained;

[0017] The temperature difference before the cooling excitation is determined according to the temperature of the de-aired area and the temperature of the non-de-aired area before the cooling excitation, and the temperature difference after the cooling excitation is determined according to the temperature of the de-aired area and the temperature of the non-de-aired area after the cooling excitation;

[0018] Determine the void thickness according to a preset size function, the temperature difference before cooling excitation, the temperature difference after cooling excitation, and the average excitation intensity of the temperature excitation device;

[0019] The above steps are repeated multiple times to obtain the final hollow thickness of the area to be detected.

[0020] Preferably, the specific process of determining the temperature difference before the cooling excitation includes:

[0021] Extracting temperature information of pixel points in the hollow region from the surface temperature field image data before cooling excitation according to the judgment result of the hollow region, and determining the hollow region temperature matrix according to the temperature information;

[0022] Determine a non-empty area according to the area to be detected and the empty area, and determine a non-empty area matrix according to temperature information of pixel points in the non-empty area;

[0023] The temperature difference before the cooling excitation is determined according to the temperature matrix of the hollow area before the cooling excitation, the matrix of the non-hollow area, the number of pixels included in the hollow area, and the number of pixels included in the non-hollow area.

[0024] Preferably, the specific process of determining the temperature difference after the cooling excitation includes:

[0025] Extracting temperature information of pixel points in the hollow region from the surface temperature field image data after cooling excitation according to the judgment result of the hollow region, and determining the hollow region temperature matrix according to the temperature information;

[0026] Determine a non-empty area according to the area to be detected and the empty area, and determine a non-empty area matrix according to temperature information of pixel points in the non-empty area;

[0027] The temperature difference after the cooling excitation is determined according to the temperature matrix of the hollow area after the cooling excitation, the matrix of the non-hollow area, the number of pixels included in the hollow area, and the number of pixels included in the non-hollow area.

[0028] The present invention also provides a CFST arch bridge void thickness detection system based on cooling excitation intensity, comprising:

[0029] A division module is used to divide the CFST arch bridge specimen to be tested into multiple areas to be tested;

[0030] An acquisition module, used for performing cooling excitation on the to-be-detected area by using a temperature excitation device, and simultaneously acquiring surface temperature field image data of the to-be-detected area before and after the cooling excitation;

[0031] An identification module, used to process the surface temperature field image data before and after the cooling excitation is applied, and determine whether there is a void area;

[0032] The calculation module is used to determine the area and thickness of the void region according to the surface temperature field image data before and after the cooling excitation when the void region exists, and to detect the remaining areas to be detected in turn after the calculation is completed.

[0033] It can be seen from the above technical solutions that, compared with the prior art, the present invention discloses a method and system for detecting the hollow thickness of a CFST arch bridge based on the cooling excitation intensity. It relies on advanced infrared imaging technology and accurately controls the cooling excitation device to generate a measurable temperature difference between the hollow area and the non-hollow area. It uses the mapping relationship between the cooling excitation device and the maximum temperature difference to achieve quantitative detection of the hollow area in the steel tube concrete structure, thereby achieving accurate quantification of the hollow thickness. It not only improves the accuracy of the detection, but also greatly speeds up the detection speed, thereby improving the overall work efficiency, reducing the dependence on the judgment of professional and technical personnel, reducing the possibility of human error, making the detection results more objective and reliable, and more effectively preventing structural failures and ensuring public safety. It also provides a scientific basis for future structural maintenance and repair. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0035] Figure 1 The overall flow chart of a CFST arch bridge void thickness detection method based on cooling excitation intensity provided by the present invention;

[0036] Figure 2 A schematic diagram of infrared image temperature extraction before cooling excitation provided in Example 1 of the present invention;

[0037] Figure 3 A schematic diagram of temperature extraction of infrared images after cooling excitation provided in Example 1 of the present invention;

[0038] Figure 4 A structural principle block diagram of a CFST arch bridge void thickness detection system based on cooling excitation intensity provided by the present invention;

[0039] Figure 5 A schematic diagram of temperature extraction of de-airing and non-de-airing regions before cooling excitation provided in Example 2 of the present invention;

[0040] Figure 6 A schematic diagram of temperature extraction of de-airing and non-de-airing areas after cooling excitation provided in Example 2 of the present invention. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments 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.

[0042] The purpose of the present invention is to provide a CFST arch bridge void thickness detection method and system based on cooling excitation intensity. Relying on advanced infrared imaging technology, by controlling the cooling excitation equipment, a measurable temperature difference is generated between the void area and the non-void area, and the mapping relationship between the cooling excitation equipment and the maximum temperature difference is utilized to realize the quantitative detection of the void area in the steel tube concrete structure. The present invention can more accurately realize the quantitative detection of the void area in the steel tube concrete structure, making the detection result more objective and reliable.

[0043] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0044] Example 1

[0045] See attached Figure 1 As shown, Embodiment 1 of the present invention discloses a method for detecting the void thickness of a CFST arch bridge based on cooling excitation intensity, comprising the following steps:

[0046] Divide the CFST (concrete-filled steel tube) arch bridge specimen to be tested into multiple areas to be tested;

[0047] The temperature excitation device is used to cool down the area to be tested, and the surface temperature field image data of the area to be tested before and after the cooling excitation is collected. The temperature excitation device can be a compressed cold air injection device, a fluid injection device, or a multi-phase fluid injection device, which is used to cool down the surface of the test piece. The cooling excitation method will not damage the concrete structure and can prevent subsequent cracking of the concrete structure.

[0048] Process the surface temperature field image data before and after applying the cooling excitation to determine whether there is a void area;

[0049] When there is a void area, the area and thickness of the void area are determined according to the surface temperature field image data before and after the cooling excitation. After the calculation is completed, the remaining areas to be detected are detected in turn.

[0050] In a specific embodiment, the specific processing process of obtaining the empty area includes:

[0051] The surface temperature field image data before and after the cooling excitation is applied is processed using an image recognition algorithm to determine whether there is a void area;

[0052] When there is a void area, an image segmentation algorithm is used to determine the area of ​​the void area, wherein the image recognition algorithm and the image segmentation algorithm may include: Region grow, K-mean, Active contour and other image recognition and segmentation algorithms, through which the area of ​​the void area can be identified and calculated.

[0053] In a specific embodiment, the specific process of obtaining the thickness of the hollow area includes:

[0054] According to the judgment result of the degassing area, the temperature of the degassing area and the temperature of the non-degassing area before the cooling excitation are obtained, and at the same time, the temperature of the degassing area and the temperature of the non-degassing area after the cooling excitation are obtained;

[0055] The temperature difference before the cooling excitation is determined according to the temperature of the de-aired area and the temperature of the non-de-aired area before the cooling excitation, and the temperature difference after the cooling excitation is determined according to the temperature of the de-aired area and the temperature of the non-de-aired area after the cooling excitation;

[0056] The hollowing thickness is determined according to the preset size function, the temperature difference before cooling excitation, the temperature difference after cooling excitation, and the average excitation intensity of the temperature excitation device. The specific expression is:

[0057]

[0058] Wherein, Y=g(A,L) represents the preset size function, Y represents the specific value of the preset size function, A is the hollow area, L is the hollow thickness, and the specific function form of g(A,L) can be determined according to the test L1, L2, ..., L n ;

[0059] Repeat the above steps n times, where n≥3, to obtain the final void thickness of the area to be detected. The specific expression is:

[0060]

[0061] In a specific embodiment, the specific process of determining the temperature difference before the cooling excitation includes:

[0062] According to the judgment result of the hollow area, the temperature information of the pixel points in the hollow area is extracted from the surface temperature field image data before the cooling excitation, and the temperature matrix of the hollow area is determined according to the temperature information;

[0063] Determine the non-empty area according to the area to be detected and the empty area, and determine the non-empty area matrix according to the temperature information of the pixel points in the non-empty area;

[0064] The temperature difference before cooling excitation is determined according to the temperature matrix of the hollow area before cooling excitation, the matrix of the non-hollow area, the number of pixels in the hollow area, and the number of pixels in the non-hollow area. The extraction results can be found in the attached Figure 2 As shown, the specific calculation formula is:

[0065]

[0066] In the formula, ΔT maxA represents the temperature difference before cooling excitation, T An,i , T Av,i They represent the pixel temperature value of the "i"th point in the temperature matrix of the non-empty area and the pixel temperature value of the "i"th point in the temperature matrix of the empty area, respectively. m and a are the number of pixels in the empty area and the non-empty area, respectively.

[0067] In a specific embodiment, the specific process of determining the temperature difference after the cooling excitation includes:

[0068] According to the judgment result of the hollow area, the temperature information of the pixel points in the hollow area is extracted from the surface temperature field image data after the cooling excitation, and the temperature matrix of the hollow area is determined according to the temperature information;

[0069] Determine the non-empty area according to the area to be detected and the empty area, and determine the non-empty area matrix according to the temperature information of the pixel points in the non-empty area;

[0070] The temperature difference after cooling excitation is determined according to the temperature matrix of the hollow area after cooling excitation, the matrix of the non-hollow area, the number of pixels in the hollow area, and the number of pixels in the non-hollow area. The extraction results can be found in the attached Figure 3 As shown, the specific calculation formula is:

[0071]

[0072] In the formula, ΔT maxB represents the temperature difference after cooling excitation, T Bn,i , T Bv,i They represent the pixel temperature value of the "i"th point in the temperature matrix of the non-empty area and the pixel temperature value of the "i"th point in the temperature matrix of the empty area, respectively. m and a are the number of pixels in the empty area and the non-empty area, respectively.

[0073] In a specific embodiment, the test area is replaced, and after the CFST surface temperature field is restored to the level before excitation, the above steps are repeated to detect the void thickness of all the areas to be tested.

[0074] See attached Figure 4As shown, an embodiment of the present invention further provides a detection system using a CFST arch bridge void thickness detection method based on cooling excitation intensity as described in any of the above embodiments, comprising:

[0075] A division module is used to divide the CFST arch bridge specimen to be tested into multiple areas to be tested;

[0076] An acquisition module is used to use a temperature excitation device to perform a cooling excitation on the area to be detected, and at the same time collect surface temperature field image data of the area to be detected before and after the cooling excitation;

[0077] An identification module is used to process the surface temperature field image data before and after the cooling excitation is applied to determine whether there is a void area;

[0078] The calculation module is used to determine the area and thickness of the void region according to the surface temperature field image data before and after the cooling excitation when there is a void region, and after the calculation is completed, the remaining areas to be detected are detected in turn.

[0079] Example 2

[0080] The specific process of applying the method of the above embodiment 1 is as follows:

[0081] The specific steps of the present invention are demonstrated by taking the infrared hollow detection of a steel tube segment as an example. The steel tube concrete has two square hollows with side lengths of 60 mm and 80 mm respectively, and the thickness of the two hollows is 15 mm. The method provided in Example 1 is used to detect the hollow thickness, and the specific detection steps are as follows:

[0082] Step 1: Cooling down incentives

[0083] The CFST specimen to be tested is subjected to cooling excitation by an excitation device with known cooling excitation intensity, and the CFST surface temperature field data before and after cooling excitation are collected, where the average excitation intensity is P C ,

[0084] Step 2: Determine the empty area

[0085] The area A of the void region is detected by relevant methods, and the shape of the void surface is marked;

[0086] Step 3: Temperature extraction of degassing and non-degassing areas before excitation

[0087] Extract the temperature field image of the previous frame before cooling excitation, and extract the temperature matrix T of the hollow area before cooling according to the hollow surface shape Av And the non-empty area temperature matrix T An For detailed results, please refer to the attached Figure 5 As shown;

[0088] Step 4: Calculation of temperature difference before excitation

[0089] By consensus Calculate the temperature difference matrix before cooling excitation, and the calculated difference shows that the temperature difference before excitation is 0.52℃;

[0090] Step 5: Temperature extraction of degassing and non-degassing areas after excitation

[0091] Extract the temperature field image of the last frame after the cooling excitation ends, and extract the temperature matrix T of the hollow area after cooling according to the hollow surface shape. Bv And the non-empty area temperature matrix T Bn For detailed results, please refer to the attached Figure 6 As shown;

[0092] Step 6: Calculation of temperature difference after excitation

[0093] By formula The temperature difference matrix after cooling excitation is calculated, and the calculated difference shows that the temperature after excitation is 1.83℃.

[0094] Step 7: Size function calculation

[0095] Using the formula The specific value (Y) of the size function is calculated. The specific function form of g(A, L) can be determined according to the test. The form of g(A, L) includes but is not limited to linear function, exponential function, logarithmic function and polynomial function. C 1000w / m 2 , g(A,L) is in the form of a quadratic polynomial, and the result is Y=0.00031℃·m 2 / w;

[0096] Step 8: Back-calculate the hollow thickness. Use the formula g(A,L)=Y to back-solve the hollow thickness L;

[0097] Step 9: Repeat the calculation, repeat steps (1) to (8) 5 times (n≥3), and obtain the hollow thicknesses of 15.3 mm, 14.8 mm, 15.5 mm, 14.7 mm, and 14.6 mm.

[0098] Step 10: Calculate the thickness of the air gap in the area to be tested. The thickness of the air gap to be tested, L, is calculated using the formula: cr =14.98mm;

[0099] Step 11: Change the test area, wait for the CFST surface temperature field to return to the level before excitation, and repeat steps (1) to (10) to detect the void thickness of all test areas.

[0100] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0101] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A CFST arch bridge void thickness detection method based on cooling excitation intensity, characterized in that: The following steps are involved: Divide the CFST arch bridge specimen to be tested into multiple areas to be tested; Using a temperature excitation device to cool the area to be detected, and collecting surface temperature field image data of the area to be detected before and after the cooling excitation; Processing the surface temperature field image data before and after applying the cooling excitation to determine whether there is a void area; When the hollow region exists, the area and thickness of the hollow region are determined according to the surface temperature field image data before and after the cooling excitation. The specific processing process includes: Obtain the temperature of the de-aired area and the temperature of the non-de-aired area before the cooling excitation, and simultaneously obtain the temperature of the de-aired area and the temperature of the non-de-aired area after the cooling excitation; The temperature difference before the cooling excitation is determined according to the temperature of the de-aired area and the temperature of the non-de-aired area before the cooling excitation, and the temperature difference after the cooling excitation is determined according to the temperature of the de-aired area and the temperature of the non-de-aired area after the cooling excitation; Determine the void thickness according to a preset size function, the temperature difference before cooling excitation, the temperature difference after cooling excitation, and the average excitation intensity of the temperature excitation device; Repeat the above steps several times to obtain the final hollow thickness of the area to be detected; After the calculation is completed, the remaining areas to be detected are detected in turn.

2. A CFST arch bridge void thickness detection method based on cooling excitation intensity according to claim 1, characterized in that: The specific process of obtaining the empty area includes: The surface temperature field image data before and after the cooling excitation is applied is processed using an image recognition algorithm to determine whether there is a void area; When there is a missing area, the image segmentation algorithm is used to determine the area of ​​the missing area.

3. A CFST arch bridge void thickness detection method based on cooling excitation intensity according to claim 1, characterized in that: The specific process of determining the temperature difference before cooling excitation includes: Extracting temperature information of pixel points in the hollow region from the surface temperature field image data before cooling excitation according to the judgment result of the hollow region, and determining the hollow region temperature matrix according to the temperature information; Determine a non-empty area according to the area to be detected and the empty area, and determine a non-empty area matrix according to temperature information of pixel points in the non-empty area; The temperature difference before the cooling excitation is determined according to the temperature matrix of the hollow area before the cooling excitation, the matrix of the non-hollow area, the number of pixels included in the hollow area, and the number of pixels included in the non-hollow area.

4. The method for detecting the void thickness of a CFST arch bridge based on the cooling excitation intensity according to claim 1 is characterized in that: The specific process of determining the temperature difference after cooling excitation includes: Extracting temperature information of pixel points in the hollow region from the surface temperature field image data after cooling excitation according to the judgment result of the hollow region, and determining the hollow region temperature matrix according to the temperature information; Determine a non-empty area according to the area to be detected and the empty area, and determine a non-empty area matrix according to temperature information of pixel points in the non-empty area; The temperature difference after the cooling excitation is determined according to the temperature matrix of the hollow area after the cooling excitation, the matrix of the non-hollow area, the number of pixels included in the hollow area, and the number of pixels included in the non-hollow area.

5. A detection system using a CFST arch bridge void thickness detection method based on cooling excitation intensity as described in any one of claims 1 to 4, characterized in that: include: A division module is used to divide the CFST arch bridge specimen to be tested into multiple areas to be tested; An acquisition module, used for performing cooling excitation on the area to be detected by using a temperature excitation device, and simultaneously acquiring surface temperature field image data of the area to be detected before and after the cooling excitation; An identification module is used to process the surface temperature field image data before and after the cooling excitation is applied to determine whether there is a void area; The calculation module is used to determine the area and thickness of the void region according to the surface temperature field image data before and after the cooling excitation when the void region exists, and to detect the remaining areas to be detected in turn after the calculation is completed.

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