Retard-bonded prestressed steel strand and sheath damage detection method thereof

Abstract

The invention relates to the technical field of steel strands, and provides a retard-bonded prestressed steel strand and a sheath damage detection method thereof.The retard-bonded prestressed steel strand comprises a prestressed steel strand body, a retard-bonded adhesive layer, a sheath and a plurality of wiring pieces, the retard-bonded adhesive layer is located between the prestressed steel strand body and the sheath, the sheath comprises an inner protective layer, a conductive layer and an outer protective layer; the conductive layer is located between the inner protective layer and the outer protective layer, and each wiring piece is connected with the sheath and is connected with the conductive layer. Therefore, automatic detection of the damage condition of the sheath can be realized by means of the conductive layer.

Description

Technical Field

[0001] The present application relates to the technical field of steel strands, and in particular to a slow-bonding prestressed steel strand and a method for detecting sheath damage thereof. Background Art

[0002] In the field of modern construction and engineering, slow-bond prestressed steel strands are widely used in various structures as an important building material. However, during its construction and use, the sheath may be damaged due to various reasons, and the use environment of slow-bond steel strands is usually more complicated, for example, in harsh environments such as high temperature or corrosion, and in such environments, the sheath is more likely to be damaged.

[0003] If the damage of the sheath of the slow-bonding prestressed steel strand is not discovered and handled in time during and after the construction process, it may lead to a series of problems, such as leakage of adhesive, affecting the stability of the structure, further expansion of the damaged area, affecting the mechanical properties of the steel strand, causing the steel strand to be corroded by external factors, and reducing its service life.

[0004] Therefore, how to effectively detect the damage of the sheath of the slow-bonding prestressed steel strand is a topic worthy of study by technical personnel in this field. Summary of the invention

[0005] In order to effectively detect the sheath damage of the slow-bonding prestressed steel strand, quickly identify the damage, and reduce the difficulty of maintenance work, the embodiment of the present application provides a slow-bonding prestressed steel strand and a method for sheath damage of the slow-bonding prestressed steel strand, so as to improve the structure of the slow-bonding prestressed steel strand to facilitate automatic detection and identification of sheath damage.

[0006] The slow-bonding prestressed steel strand comprises a prestressed steel strand, a slow-bonding adhesive layer, a sheath and a plurality of terminal blocks, wherein the slow-bonding adhesive layer is located between the prestressed steel strand and the sheath, wherein the sheath comprises an inner sheath, a conductive layer and an outer sheath; the conductive layer is located between the inner sheath and the outer sheath, and each of the terminal blocks is connected to the sheath and to the conductive layer.

[0007] Based on the above technical solution, the sheath structure of the slow-bonding prestressed steel strand is improved so that it can be detected by the method provided in the embodiment of the present application, thereby realizing automatic identification of jacket damage. At the same time, by setting a multi-level sheath structure, the strength and corrosion resistance of the sheath structure can be improved to a certain extent, and the service life can be extended.

[0008] In one implementation, the conductive layer is a resistive wire mesh.

[0009] In one implementation, the resistance wire mesh includes a plurality of metal wires arranged along a length direction, and a metal ring arranged along a cross-sectional direction, wherein the metal ring is sleeved on the metal wires.

[0010] In one embodiment, the connecting member includes two connecting terminals, a ring member and at least one conductive feeler.

[0011] In one embodiment, at the connection between the wiring member and the sheath, the outer sheath 133 is provided with a perforation for exposing the conductive layer, and the shape of the perforation matches the conductive antenna so that the conductive antenna can pass through the perforation to connect with the conductive layer.

[0012] Based on the above technical solution, by arranging the conductive feelers to pass through the outer protective layer and connect with the conductive layer, the conductive layer can be protected to the greatest extent to prevent the conductive layer from being over-exposed and affecting the structural stability.

[0013] The method for detecting damage to the sheath of a slow-bonding prestressed steel strand provided in an embodiment of the present application is used to detect the sheath of the above-mentioned slow-bonding prestressed steel strand, and is implemented based on a detection and analysis server, comprising the steps of: inputting a detection signal to one of the wiring members in the slow-bonding prestressed steel strand, and obtaining an output signal corresponding to the detection signal received at the other wiring members; and determining whether the sheath is damaged based on the output signal.

[0014] Based on the above technical solution, when the conductive layer is damaged, or when the conductive layer structure is affected by damage to other layers of the sheath, the resistance of the conductive layer changes. Based on this, by analyzing the output signal, it is possible to identify whether the sheath is damaged, thereby achieving automatic detection of the sheath.

[0015] In one embodiment, the method for determining whether the sheath is damaged based on the output signal includes: preprocessing the output signal; calculating the difference between the preprocessed output signal and the input current signal, and if the difference exceeds a preset range, determining that the sheath is damaged; or, identifying the preprocessed output signal based on a structural recognition model, and determining whether the sheath is damaged according to the recognition result.

[0016] In one embodiment, there are multiple output signals, which are obtained from multiple wiring members respectively. The method for determining whether the sheath is damaged based on the output signals includes: identifying each of the output signals based on the structural recognition model to obtain a corresponding recognition result; based on each of the recognition results and the position of each of the wiring members, determining whether the sheath is damaged and the location of the damage.

[0017] Based on the above technical solution, the damaged position can be further located, thereby providing maintenance personnel with a more accurate maintenance range.

[0018] In one implementation, the output signal includes an output current signal and an acoustic emission signal. The method for determining whether the sheath is damaged based on the output signal includes: identifying the damage of the sheath based on the output current signal and the acoustic emission signal, respectively, and correcting each of the identification results based on maintenance feedback to optimize the corresponding identification method.

[0019] Based on the above technical solution, dual detection of jacket damage is achieved by combining acoustic emission technology, and the accuracy of the two methods is analyzed based on the manual feedback results. Then, the two analysis methods are optimized according to the manual feedback results, making the structural recognition model and the recognition process of acoustic emission technology more and more accurate.

[0020] In one embodiment, before the step of inputting the detection signal, the method further includes: sending a corresponding detection signal to the current generator and each current detection device, and determining whether the current generator and each current detection device are in a working state based on the received response signal.

[0021] Based on the above technical solution, before each test, the working status of each device is automatically confirmed to ensure that the test process is not affected by equipment abnormalities, to ensure the test efficiency and the reliability of the test results. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings constituting a part of the present application are used to provide further understanding of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute improper limitations on the present application.

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0024] Figure 1 A cross-sectional view of a slow-bonding prestressed steel strand provided in an embodiment of the present application is shown.

[0025] Figure 2 A schematic diagram of the unfolded structure of the conductive layer in an embodiment of the present application is shown.

[0026] Figure 3 A cross-sectional view of the slow-bonding prestressed steel strand provided in an embodiment of the present application at a terminal piece is shown.

[0027] Figure 4 A schematic diagram of the structure of a detection system provided in an embodiment of the present application is shown.

[0028] Figure 5 A flow chart of a method for detecting sheath damage of a slow-bonding prestressed steel strand provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0030] In the description of the embodiments of the present application, unless otherwise specified, "multiple" means two or more, and "first", "second" and various digital numbers are only distinguished for the convenience of description and are not used to limit the scope of the embodiments of the present application.

[0031] The features, structures or characteristics in this application may be combined in one or more embodiments in any suitable manner. In various embodiments of this application, the size of the sequence number of each process does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0032] Some optional features in the embodiments of the present application may be implemented independently in some scenarios without relying on other features to solve corresponding technical problems and achieve corresponding effects. They may also be combined with other features in some scenarios as needed.

[0033] In this application, unless otherwise specified, the same or similar parts between the various embodiments can refer to each other. In the various embodiments of this application, if there is no special description and logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced to each other, and the technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationships. The implementation methods of this application do not constitute a limitation on the scope of protection of this application.

[0034] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0035] Please refer to Figure 1 The slow-bonding prestressed steel strand 1 provided in the embodiment of the present application comprises a prestressed steel strand 11, a slow-bonding adhesive layer 12, a sheath 13 and at least two terminal pieces 14, wherein the slow-bonding adhesive layer 12 is located between the prestressed steel strand 11 and the sheath 13.

[0036] The sheath 13 includes an inner sheath 131, a conductive layer 132 and an outer sheath 133. The conductive layer 132 is located between the inner sheath 131 and the outer sheath 133. The inner sheath 131 is the layer structure closest to the prestressed steel strand 11 in the sheath 13 and is located between the slow-bonding prestressed adhesive layer 12 and the conductive layer 132.

[0037] Each of the wiring members 14 is connected to the sheath 13 and to the conductive layer 132 .

[0038] Specifically, in the embodiment of the present application, the sheath 13 is configured as a multi-layer structure to enhance the protection of the prestressed steel strands 11 and the slow-bonding adhesive layer 1 .

[0039] In one example, the manufacturing process of the sheath 13 includes laying a conductive layer before the inner sheath material is cured, coating the outer sheath material on the conductive layer, and then curing the inner sheath material and the outer sheath material to finally form the sheath 13. After the sheath 13 is formed, it is directly sleeved on the outside of the prestressed steel strand 11, and then the slow-bonding adhesive material is filled between the sheath 13 and the prestressed steel strand 11 to finally complete the manufacturing of the slow-bonding prestressed steel strand.

[0040] In another example, the process of forming the sheath 13 may include coating the surface of the steel strand 11 with the slow-bonding adhesive material, coating the inner sheath material, laying out the conductive layer before the inner sheath material is cured, coating the outer sheath material on the conductive layer, and then curing the inner sheath material and the outer sheath material to finally form the sheath 13. The coating step of the outer sheath material includes extrusion, so that the outer sheath material is connected to the inner sheath material through the metal wire gap, thereby ensuring the stability of the finally formed sheath structure.

[0041] The outer sheath material may be the same as or different from the inner sheath material.

[0042] In one embodiment, the outer protective layer and the inner protective layer materials both use high-density polyethylene (HDPE) as the base resin, and a blended resin with polar groups, such as ethylene acrylic acid copolymer (EAA), ethylene vinyl acetate copolymer (EVA), maleic anhydride grafted high-density polyethylene (HDPE-g-MAH), glycidyl methacrylate grafted high-density polyethylene (HDPE-g-GMA), etc., are added to enhance the performance of the material.

[0043] In another embodiment, a reinforcing agent treated with a coupling agent, such as glass fiber, carbon fiber, talcum powder, calcium carbonate, wollastonite, mica, etc., may be further added to the outer sheath material or the inner sheath material to improve the mechanical strength and durability of the outer sheath material.

[0044] Please refer to Figure 2In one example, the conductive layer 132 may be a resistance wire mesh, specifically including a plurality of metal wires 132a arranged along the length direction, and a metal ring 132b arranged along the cross-sectional direction, the metal ring 132b is sleeved on the metal wire 132a, and is used to reinforce and support each metal wire.

[0045] In a specific example, the material of the metal wire 132a can be copper, with a diameter of 1mm to 1.5mm, and the material of the metal ring 132b can be iron. The spacing between the metal wires is 10mm, and the spacing between the metal rings is 2000mm. By using copper wire to improve the flexibility of the conductive layer structure, using iron rings as reinforcement supports for the copper wires not only does not affect the conductivity of the metal wires, but also improves the structural strength of the conductive layer. Figure 2 The conductive layer structure shown does not affect the flexibility of the slow-bonding prestressed steel strand 1, and can be flexibly applied when the slow-bonding prestressed steel strand 1 is deformed and bent due to construction, thereby maintaining the integrity of the conductive layer structure.

[0046] In the embodiment of the present application, the damage of the sheath can be detected by inputting a current signal into the conductive layer 132. The wiring member 14 is used to connect to the conductive layer 132 to transmit the received current signal to the conductive layer 132 to facilitate the access of external detection equipment, while preventing the sheath structure from being easily damaged by environmental corrosion due to direct exposure of the conductive layer 132.

[0047] In an example, see Figure 3 The wiring member 14 is an annular structure, including two wiring terminals 141, an annular member 142 and at least one conductive antenna 143, wherein the two wiring terminals 141 are connected to the outer circumferential surface of the annular member 142 for equipment wiring. The conductive antenna 143 is cylindrical or annular, connected to the inner circumferential surface of the annular member 142, and is used to connect to the conductive layer 132. The wiring terminals 141 and the conductive antenna 143 are both made of conductive materials and are conductive to each other. In one embodiment, the annular member 142 can be made of insulating material or conductive material. When the annular member 142 is made of insulating material, it can avoid the situation where the current signal transmission or detection is affected by the damage of the annular member to a certain extent.

[0048] Specifically, at the connection between the terminal 14 and the sheath 13, a perforation is provided on the outer sheath 133 to expose the position of the metal wire of the conductive layer 132. The shape of the perforation is adapted to the conductive feeler 143, and the inner diameter is slightly smaller than the inner diameter of the conductive feeler 143, so that the conductive feeler 143 can pass through the perforation to contact the conductive layer 132, and is tightly clamped in the perforation by squeezing the outer sheath 133. In one embodiment, the length of the conductive feeler 143 is equal to or slightly smaller than the thickness of the outer sheath, and the width of the conductive feeler 143 is smaller than the width of the annular member 142. Therefore, after the terminal 14 is installed, a certain degree of squeezing is generated on the outer sheath 133, so that the conductive feeler 143 can be in close contact with the conductive layer.

[0049] In this way, after the connecting piece 14 is fixed on the outer sheath 133, the outer sheath can be pressed tightly, thereby ensuring the tightness of the connection and preventing the perforation from being corroded by the external environment.

[0050] It is worth noting that the corresponding relationship between the conductive antenna 143 and the metal wire can be one-to-one or one-to-many, that is, one conductive antenna 143 is connected to one metal wire, or one conductive antenna 143 is connected to multiple metal wires, so that each metal wire can be connected to the corresponding conductive antenna. In the detection process, the current signal can be connected. Figure 3 In the illustrated embodiment, there is one conductive feeler 143 in a ring shape for connecting to all metal wires.

[0051] In some embodiments, the tight connection between the wiring member 14 and the outer sheath 133 can be enhanced by gluing, that is, glue is filled between the wiring member 14 and the outer sheath 133 to achieve a stable connection.

[0052] The slow-bonding prestressed steel strand provided in the embodiment of the present application can not only detect sheath damage, but also improve the sheath structural strength.

[0053] The method for detecting damage to the sheath of the slow-bonding prestressed steel strand provided in the embodiment of the present application can be used to detect the sheath of the slow-bonding prestressed steel strand. The method is implemented based on the detection system. Please refer to Figure 4 The detection system includes a detection and analysis server 41, a detection signal input device 42, and an output signal acquisition device 43, wherein the detection signal input device 42 and the output signal acquisition device 43 are both communicatively connected to the analysis server 41. During the detection process, the detection signal input device 42 is connected to a wiring component, and the output signal acquisition device 43 is connected to other wiring components, wherein the output signal acquisition device 43 and the other wiring components are in a one-to-one correspondence.

[0054] In one implementation, the detection signal input device 42 includes a current generator, and the output signal acquisition device 43 includes a current detection device, such as a current sensor.

[0055] Please refer to 5. The method for detecting damage of the sheath of the slow-bonding prestressed steel strand provided in the embodiment of the present application specifically includes the following steps.

[0056] S510, inputting a detection signal to a connection piece in the slow-bonding prestressed steel strand, and receiving an output signal corresponding to the detection signal at other connection pieces.

[0057] In one embodiment, the detection signal is a current signal, which can be obtained by connecting a current generator at a wiring member to input the current signal to the conductive layer by controlling the current generator, and detecting the output current signal at other wiring members through a current detection device and sending it to a detection and analysis server.

[0058] Specifically, during the detection process, the detection and analysis server first determines the equipment connection plan based on the number and distribution of wiring components on the tested steel strands, and outputs the connection plan to the detection personnel so that the detection personnel can complete the equipment connection. For example, the wiring components located at both ends of the steel strands are selected, one is connected to the current generator, and the other is connected to the current detection device. The remaining terminals in the middle section are selected for connection according to the detection purpose.

[0059] After the tester completes the device access according to the connection plan, the client program can input the installation completion notification to the detection and analysis server. After receiving the installation completion notification, the detection and analysis server enters the installation detection state.

[0060] In the installation detection state, the detection and analysis server sends corresponding detection signals to the current generator and each current detection device, and determines whether each device is in a working state based on the response signal returned by each device.

[0061] In one example, the detection signal sent by the detection and analysis server to the current generator includes a first control instruction to instruct the current generator to output the current signal in a first set time period, and return a first response message after the output is completed. In addition, the detection signal sent by the detection and analysis server to each current detection device includes a second control instruction to instruct each current detection device to collect the output signal in a second set time period, and send the collected output signal to the detection and analysis server, and immediately send a second response message after receiving the detection signal. The duration corresponding to the second set time period is greater than the first set time period and covers the first set time period.

[0062] After the second time period, the detection and analysis server analyzes the working status of the current generator and each current detection device based on the received response information and the response information and output signals sent by each current detection device.

[0063] For example, when the sending time of the first response information is after the first set time period, it is determined that the working state of the current generator is normal, otherwise, it is abnormal. When the second response information and the output signal can be received, it is determined that the current detection device is normal, otherwise, it is abnormal. When the relevant equipment is found to be abnormal, the detection and analysis server promptly notifies the on-site detection personnel through client presentation, telephone, etc., and makes installation adjustments. The detection will not start until all equipment is in working condition. Based on this, the communication status and operation status of each device can be detected at the same time to ensure the smoothness of the detection process.

[0064] During the detection process, the detection and analysis server sends a third control instruction to the current generator to instruct the current generator to generate a corresponding current signal at a specified frequency, duration, and magnitude. At the same time, a fourth control instruction is sent to the current detection device to instruct the current detection device to continuously collect output signals during the entire detection process, including output signals when the current generator has output and when it has no output.

[0065] S520: Determine whether the sheath is damaged based on the output signal.

[0066] After receiving the output signal, the collected output signal can be pre-processed, including filtering, denoising, etc., to improve the signal quality.

[0067] In one example, during the above-mentioned detection process and the testing process, the output signal collected during the period when the current generator has no output can be used as a background signal to perform noise reduction processing on the output signal collected during the period when the current generator has an output.

[0068] In one implementation, the detection and analysis server can compare the pre-processed output signal with the input current signal. If the difference exceeds a preset range, it indicates that the conductive layer may be damaged or in contact with air, steel strands, or a slow-adhesive agent, and therefore, it can be determined that the sheath structure is damaged. The preset range is determined based on the difference between the output signal in an undamaged state and the input current signal.

[0069] In another implementation, the detection and analysis server may input the preprocessed output signal into a structure recognition model to obtain a corresponding recognition result, which includes whether the sheath between the two connectors is damaged. The structure recognition model may be constructed based on a support vector machine (SVM) or a neural network, and after extracting features from the output signal, it may identify whether the sheath is damaged, the type of damage, and the area of ​​damage based on the extracted features.

[0070] It has been found in practice that when the sheath is damaged, the wire mesh will be affected to varying degrees, such as the wire is broken, oxidized, stretched or in contact with the steel strand, which will change the resistance of the wire mesh. Therefore, the current signal will attenuate during the transmission process. Based on this, through simulation experiments, the output signals corresponding to different current signal inputs under various known damage states are obtained, and the selection of recognition features is determined by analyzing the effective features in each output signal, and then the corresponding training samples are generated to train the structure recognition model. At the same time, the corresponding current signal input requirements are determined for the control of the current generator during the detection process.

[0071] In one example, the feature extraction method may include analyzing the output signal in the time domain, frequency domain, and time-frequency domain to extract feature values ​​related to the damage state of the sheath. For example, the output signal may be decomposed into different frequency bands using methods such as wavelet packet decomposition to extract sensitive feature values.

[0072] It can be understood that in actual applications, according to actual needs, it is possible to choose to set up multiple wiring members at intervals, obtain corresponding output signals respectively, and input each output signal into the structural identification model respectively, so as to obtain the damage of the sheath between the current generator connecting the wiring member and other wiring members respectively for identification, thereby locating the damage.

[0073] For example, if the tested sheath is connected to three terminals A, B and C in sequence, where A is used to connect to the current generator, the output signals collected at B and C are respectively input into the structural identification model to obtain the damage conditions of the AB segment sheath and the AC segment sheath. When the damage condition of the AB segment sheath indicates normal, and the damage condition of the AC segment indicates damage, it can be determined that the location of the damage is between BC; when both AB and AC segments are damaged, the damage conditions of AB and BC segments are determined based on the change in the damaged area. If the damaged area in the identification result corresponding to the AC segment is larger than that of AB, it is determined that both AB and BC are damaged. In this way, not only can it be identified whether the sheath is damaged, but also the damaged area can be determined based on the position of the terminal. This makes it easy for maintenance personnel to quickly locate and repair the damage.

[0074] Furthermore, in other embodiments of the present application, the detection system also includes an acoustic emission acquisition host and an acoustic emission sensor, wherein the detection and analysis server is in communication connection with the acquisition host, and the acoustic emission sensor is fixedly mounted on the sheath for periodic or real-time acquisition of acoustic emission signals, and sent to the detection and analysis server for analysis, so as to achieve periodic or real-time monitoring of sheath damage. The specific monitoring cycle can be selected according to actual application requirements. For example, for steel strands at key structures of buildings, real-time monitoring or short-cycle monitoring can be set for key monitoring.

[0075] Acoustic emission acquisition sensors collect stress wave signals generated by the rapid release of strain energy caused by crack expansion, plastic deformation or phase change in the material to collect changes in material structure.

[0076] In an embodiment of the present application, when the sheath is damaged, if the acoustic emission sensor monitors the stress wave signal generated at the moment of damage in real time, the detection and analysis server can determine whether the sheath is damaged based on the signal and the pre-extracted features, wherein the pre-extracted features are identification features obtained by analyzing the stress wave signals collected under different damage conditions, and are used to identify whether the feature is protected in the current signal. If it is included, it is determined that damage exists.

[0077] In the application scenario of non-real-time monitoring, when the sheath is damaged, the adhesive will flow out. This process lasts for a long time. Therefore, by periodically monitoring the acoustic emission signal of the sheath, the acoustic emission signal generated by the flow of the adhesive can be obtained. Based on this, the real-time or periodic automatic monitoring of the sheath can be achieved. It is understandable that the characteristics of the acoustic emission signal at the moment of sheath damage and during the adhesive flow process can be obtained through experiments, which can be used for identification during the monitoring process.

[0078] In one implementation, during the above-mentioned current signal detection process, the detection and analysis server can also simultaneously collect and analyze the acoustic emission signals in the process to synchronously identify whether the sheath is damaged, and determine whether there is damage based on two recognition results. For example, when any recognition result indicates damage, the detection and analysis server sends a maintenance notice to the inspection personnel, and based on the actual damage returned by the inspection personnel after the maintenance, corrects each recognition result, and then optimizes the recognition method based on the corrected recognition results and the corresponding output signals, specifically including generating new sample data to further optimize the training of the structural recognition model, and extracting features based on the corresponding acoustic emission signals.

[0079] It is worth noting that due to the differences in the construction methods and final usage status of steel strands in various building structures, the training samples of the structural recognition model obtained in the early stage cannot cover all damage conditions, and the acoustic emission recognition features cannot be fully collected in the early stage. Therefore, there may be inaccurate recognition results in the early stage of application. By combining the two recognition methods and notifying the maintenance personnel to carry out inspections when any recognition result indicates damage, the two methods can be optimized according to the manual recognition results. As the years of use progress, the structural recognition model and acoustic emission features continue to be close to the actual situation of the building, and the recognition accuracy rate is continuously improved. This can better meet the needs of more accurately identifying various types of damage after entering the vulnerable period after long-term use.

[0080] It is worth noting that collecting and analyzing acoustic emission signals during the current signal detection process can more accurately capture the damage situation. The reason is that when the sheath is damaged, during the transmission of the current signal, according to the thermal effect of the current, a more obvious thermal effect will be generated at the damaged part of the metal mesh, and the temperature will rise. When the structure is unstable, the temperature increase will cause structural changes and generate specific acoustic emission signals. Based on this, by collecting and analyzing the acoustic emission signals at the same time, the accuracy of judging the damage situation can be improved.

[0081] It can be seen that based on the above method, by inputting a current signal to the conductive layer and collecting an output current signal, the damage of the sheath can be analyzed based on the output current signal, thereby realizing automatic identification of the damage of the sheath of the slow-bonding prestressed steel strand, and by using multiple connection terminals, the location of the damage can be analyzed to assist maintenance personnel in quickly locating the damaged part and improve maintenance efficiency. Furthermore, by combining acoustic emission detection technology to realize real-time or periodic monitoring of the sheath, the damage of the sheath can be discovered more promptly and then repaired.

[0082] Those skilled in the art can understand that all or part of the steps in the above-mentioned implementation methods can be completed by instructing related hardware through a program, and the program is stored in a storage medium, including several instructions for making a device (which can be a single-chip microcomputer, chip, etc.) or a processor (processor) perform all or part of the steps of each implementation method of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0083] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A slow-bonding prestressed steel strand, characterized in that: It includes a prestressed steel strand, a slow-bonding adhesive layer, a sheath and a plurality of wiring members, wherein the slow-bonding adhesive layer is located between the prestressed steel strand and the sheath, wherein the sheath includes an inner sheath, a conductive layer and an outer sheath; the conductive layer is located between the inner sheath and the outer sheath, and each of the wiring members is connected to the sheath and to the conductive layer.

2. The slow-bonding prestressed steel strand according to claim 1, characterized in that: The conductive layer is a resistance wire mesh.

3. The slow-bonding prestressed steel strand according to claim 2, characterized in that: The resistance wire mesh comprises a plurality of metal wires arranged along the length direction and a metal ring arranged along the cross-sectional direction, wherein the metal ring is sleeved on the metal wires.

4. The slow-bonding prestressed steel strand according to claim 1, characterized in that: The connecting piece comprises two connecting terminals, a ring piece and at least one conductive feeler.

5. The slow-bonding prestressed steel strand according to claim 4, characterized in that: At the connection between the wiring member and the sheath, the outer sheath 133 is provided with a perforation for exposing the conductive layer, and the shape of the perforation is adapted to the conductive antenna, so that the conductive antenna can pass through the perforation and connect to the conductive layer.

6. A method for detecting damage to the sheath of a slow-bonding prestressed steel strand, characterized in that: The method is used to detect the sheath of the slow-bonding prestressed steel strand according to any one of claims 1 to 5, and is implemented based on a detection and analysis server, comprising the steps of: Inputting a detection signal to one of the wiring members in the slow-bonding prestressed steel strand, and obtaining an output signal corresponding to the detection signal received at the other wiring members; Whether the sheath is damaged is determined based on the output signal.

7. The method according to claim 6, characterized in that The method for determining whether the sheath is damaged based on the output signal comprises: Preprocessing the output signal; Calculating the difference between the pre-processed output signal and the input current signal, and if the difference exceeds a preset range, determining that the sheath is damaged; or, The preprocessed output signal is identified based on a structure recognition model, and whether the sheath is damaged is determined according to the identification result.

8. The method according to claim 7, characterized in that The output signals are multiple, and are obtained from multiple wiring members respectively. The method for determining whether the sheath is damaged based on the output signals includes: Identify each of the output signals based on the structure recognition model to obtain a corresponding recognition result; Based on the identification results and the positions of the wiring members, it is determined whether the sheath is damaged and the damaged position.

9. The method according to claim 6, characterized in that The output signal includes an output current signal and an acoustic emission signal. The method for determining whether the sheath is damaged based on the output signal includes: identifying the damage of the sheath based on the output current signal and the acoustic emission signal respectively, and correcting each of the identification results based on maintenance feedback to optimize the corresponding identification method.

10. The method according to claim 6, characterized in that Before the step of inputting a detection signal, the method further includes: A corresponding detection signal is sent to the current generator and each current detection device, and according to the received response signal, it is determined whether the current generator and each current detection device are in working state.

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