Quantitative monitoring system for interface bonding state of steel and concrete composite structure

Abstract

The invention provides a quantitative monitoring system for the interface bonding state of a steel and concrete composite structure, and relates to the technical field of structure monitoring, the system adopts an electromagnetic induction eddy current measurement technology, a small hole is reserved in a steel plate, a thin steel bar penetrates through and is pre-embedded in concrete, then an electromagnetic induction probe is fixed at the extending end of the steel bar, and the electromagnetic induction eddy current measurement is carried out. And keeping a certain distance from the surface of the steel member. The probe is powered by a three-way output switching power supply, and the impedance change of the probe is measured in real time by using a dynamic acquisition instrument. The bonding state or stripping degree of the interface can be quantitatively monitored by analyzing the relation between the probe impedance and the steel member distance. The method has the advantages of no damage, high sensitivity, long-term monitoring and the like, is suitable for monitoring the interface state of the steel-concrete composite structure, and is beneficial to improving the safety and reliability of the structure.

Description

Technical Field

[0001] The invention relates to the technical field of structure monitoring, and in particular to a quantitative monitoring system for the interface bonding state of a steel and concrete composite structure. Background Art

[0002] In modern construction projects, steel-concrete composite structures are widely used due to their excellent mechanical properties and economy. The performance of such structures depends largely on the interfacial bonding between steel components and concrete. However, due to a variety of factors, such as shrinkage and creep of concrete, uneven vibration during construction, and the complex geometry of steel components, debonding may occur at the interface between steel and concrete. This debonding can significantly reduce the bearing capacity and stiffness of the structure, affecting its safety and service life.

[0003] At present, the methods used to detect the debonding of the steel and concrete interface mainly include the tapping method, fiber optic sensing method, impact echo method and ultrasonic method. Among them, the tapping method mainly relies on the experience of the operator, has no objective judgment standard, is difficult to achieve quantitative analysis, has low judgment accuracy, and is not effective in the case of thick steel plates. Although the fiber optic sensing method has high sensitivity, it has poor stability in concrete, low survival rate in concrete, and high cost. Although the impact echo method can provide certain quantitative information, its detection ability for complex structures is limited, it is difficult to quantitatively judge the size of interface debonding, and it is difficult to achieve long-term monitoring. The ultrasonic method also has the problem of insufficient detection accuracy in some cases. For example, it is not applicable to the detection of interface debonding defects inside steel plates.

[0004] In addition, most existing monitoring methods are offline detection, which cannot achieve real-time and continuous monitoring of the structural interface status. This makes it difficult to timely discover and deal with interface debonding problems during the use of the structure, increasing the risk of structural failure. Therefore, developing a method that can monitor the bonding and debonding status of the steel-concrete interface in real time, online, and quantitatively is of great significance to improving the safety and reliability of the structure.

[0005] In view of this, this application is filed. Summary of the invention

[0006] The present invention provides a monitoring system for the bonding and peeling state of the interface of a steel and concrete composite structure, which can effectively solve the above problems.

[0007] To achieve the above object, the present invention adopts the following technical solutions: A quantitative monitoring system for the interface bonding state of a steel-concrete composite structure, comprising: a control component, a steel-concrete composite component, a fixing component, and an electromagnetic induction eddy-electric detection component, wherein a data end of the control component is electrically connected to a data end of the electromagnetic induction eddy-electric detection component, and the electromagnetic induction eddy-electric detection component is arranged on the steel-concrete composite component through the fixing component; The control component is configured to implement the following steps by executing a computer program stored therein: Acquiring detection data collected by the electromagnetic induction eddy current detection component, and calculating and processing the detection data according to a response equation to obtain an equivalent impedance of eddy currents in the steel and concrete composite component; The equivalent impedance is simplified, and based on the simplified equivalent impedance, a quantitative monitoring result of interface peeling is obtained, wherein the equivalent impedance is only affected by the distance d between the steel-concrete composite component and the eddy current detection assembly.

[0008] In summary, the monitoring system for the bonding state of the interface of the steel and concrete composite structure reserves a small hole on the steel plate, passes the thin steel bar through and pre-buries it in the concrete, and then uses a connecting plate to fix the electromagnetic induction probe at the end of the steel bar to keep a certain distance from the outer wall of the steel member. The probe is powered by a three-way output switching power supply, and the impedance change of the electromagnetic induction probe is measured in real time using a dynamic data acquisition instrument. According to the quantitative relationship between the impedance of the electromagnetic induction probe and the distance from the outer wall of the steel member, the bonding state or peeling degree of the interface can be accurately monitored. This method has the advantage of non-destructive monitoring, avoiding damage to the structure itself, and has high sensitivity, can detect small interface changes, can quantitatively monitor small changes in the interface of the steel and concrete composite structure, and promptly discover the peeling problem of the structure during use. In addition, the system can realize long-term, online monitoring without manual intervention, reducing monitoring costs and labor intensity, improving monitoring efficiency, and can continuously track changes in the state of the structural interface, providing reliable data support for the safety assessment and maintenance of the structure. Compared with traditional monitoring methods, this system overcomes their limitations in practical applications, such as reliance on operator experience, high cost, poor stability, and insufficient detection accuracy, and provides a more accurate, reliable, and efficient monitoring method.

[0009] In addition, the device is suitable for monitoring the bonding condition of steel sections, steel plates or steel pipes and concrete interfaces in various steel-concrete composite structures. It is of great significance for ensuring the safety and reliability of the structure, has broad application prospects, and can provide an effective monitoring solution for the field of construction engineering, promoting the development of structural monitoring technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1It is a schematic diagram of the composition of a quantitative monitoring system for the interfacial bonding state of a steel-concrete composite structure provided by an embodiment of the present invention; Figure 2 is a schematic diagram of installation details of the electromagnetic induction probe provided in an embodiment of the present invention; Figure 3 is a schematic diagram of steel bar installation provided by an embodiment of the present invention; Figure 4 It is a schematic diagram of the principle of a quantitative monitoring system for the interfacial bonding state of a steel-concrete composite structure provided by an embodiment of the present invention; Figure 5 This is a schematic diagram of monitoring the first day peeling of a quantitative monitoring system for the bonding state of the interface of a steel and concrete composite structure provided by an embodiment of the present invention; Figure 6 It is a schematic diagram of monitoring the peeling condition on the second day of the quantitative monitoring system for the bonding state of the interface of the steel and concrete composite structure provided by the embodiment of the present invention; Figure 7 It is a schematic diagram of monitoring the peeling condition in the first month of the quantitative monitoring system for the interfacial bonding state of the steel and concrete composite structure provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0011] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0012] refer to Figures 1 to 3 As shown, the first embodiment of the present invention discloses a quantitative monitoring system for the interface bonding state of a steel-concrete composite structure, which includes: a control component, a steel-concrete composite component, a fixing component, and an electromagnetic induction eddy-electric detection component, wherein the data end of the control component is electrically connected to the data end of the electromagnetic induction eddy-electric detection component, and the electromagnetic induction eddy-electric detection component is arranged on the steel-concrete composite component through the fixing component; Preferably, the steel and concrete composite component comprises a steel component module 1 and concrete 2, wherein the concrete 2 is poured in the steel component module 1, and a vent hole is provided on a first end surface of the steel component module 1.

[0013] See also Figure 2 Preferably, the fixing component includes a steel bar 5, a soft sleeve 6, and a first nut 7. The soft sleeve 6 is movably clamped on the exhaust hole. The first end of the steel bar 5 passes through the soft sleeve 6 and is poured into the steel component module 1 together with the concrete 2. The electromagnetic induction eddy current detection component is arranged at the second end of the steel bar 5 through the first nut 7.

[0014] In this embodiment, the data end of the control component is electrically connected to the data end of the electromagnetic induction eddy-electric detection component to ensure real-time transmission and processing of data. The electromagnetic induction eddy-electric detection component is configured on the steel and concrete composite component through a fixed component to achieve accurate monitoring of the interface state. Specifically, the steel and concrete composite component consists of a steel component module 1 and concrete 2, and the concrete 2 is poured in the steel component module 1. An exhaust hole is provided on the first end face of the steel component module 1. This design not only helps to discharge gas during the pouring of concrete 2, but also provides convenience for the installation of subsequent monitoring components. The fixed component includes a steel bar 5, a soft sleeve 6 and a first nut 7. The soft sleeve 6 is movably clamped on the exhaust hole, and the first end of the steel bar 5 passes through the soft sleeve 6 and is poured in the steel component module 1 together with the concrete 2. This design allows the steel bar 5 to be tightly combined with the concrete 2, which can effectively transmit the contraction and deformation of the concrete, thereby driving the movement of the electromagnetic induction eddy-electric detection component to achieve monitoring of the interface state. After the concrete 2 is initially set, the soft sleeve 6 is removed to avoid friction caused by the soft sleeve 6 on the shrinkage of the concrete 2, which may cause errors in the detection results. The electromagnetic induction eddy current detection component is arranged at the second end of the steel bar 5 through the first nut 7, ensuring stable installation of the component.

[0015] See also Figure 3 Preferably, the electromagnetic induction eddy electric detection assembly includes an electromagnetic induction probe 3, a connecting plate 4, and a second nut 8. The first end of the connecting plate 4 is configured on the second end of the steel bar 5 through the first nut 7, and the electromagnetic induction probe 3 is configured at the second end of the connecting plate 4 through the second nut 8. The electromagnetic induction probe 3 is perpendicular to the first end face of the steel component module 1, wherein the detection head of the electromagnetic induction probe 3 faces the steel and concrete composite component and there is a preset distance. The electromagnetic induction probe 3 is configured to measure the relative displacement change between the steel component module 1 and the detection head under static conditions or dynamic conditions.

[0016] Preferably, the monitoring accuracy of the electromagnetic induction probe 3 is 5×10 -4 mm.

[0017] In this embodiment, the first end of the connecting plate 4 is arranged on the second end of the steel bar 5 through the first nut 7, and the electromagnetic induction probe 3 is arranged on the second end of the connecting plate 4 through the second nut 8. The eddy current induction probe 3 is perpendicular to the first end face of the steel component module 1, and its detection head faces the steel and concrete composite component and maintains a preset distance from the steel component module 1. This design enables the electromagnetic induction probe 3 to measure the relative displacement change between the steel component module 1 and the detection head under static or dynamic conditions, thereby accurately reflecting the bonding and peeling state of the interface. The monitoring accuracy of the electromagnetic induction probe is as high as 5×10 -4mm, which can quantitatively monitor small changes in the interface and provide reliable data support for the safety assessment of the structure.

[0018] The electromagnetic induction probe 3 is a non-contact measurement method that can measure the relative displacement change between the steel component module 1 and the electromagnetic induction probe 3 in the steel-concrete composite component in static and dynamic conditions.

[0019] Preferably, the control component includes a controller 11, a dynamic collector 10, a three-way output switching power supply 12, and a transmission line 9. The output end of the three-way output switching power supply 12 is electrically connected to the power end of the electromagnetic induction probe 3 and the power end of the dynamic collector 10. The electromagnetic induction probe 3 is electrically connected to the dynamic collector 10 through the transmission line 9, and the data end of the dynamic collector 10 is electrically connected to the data end of the controller 11.

[0020] In this embodiment, the output end of the three-way output switching power supply 12 is electrically connected to the power end of the electromagnetic induction probe 3 and the power end of the dynamic collector 10, ensuring the stable power supply of the monitoring system. The electromagnetic induction probe 3 is electrically connected to the dynamic collector 10 through the transmission line 9, and the data end of the dynamic collector 10 is electrically connected to the data end of the controller 11. This design realizes the real-time collection and processing of the output signal of the electromagnetic induction probe 3. The controller 11 can analyze the bonding and peeling state of the interface in real time based on the collected data, and provide corresponding early warning information. The entire monitoring system has the advantages of non-destructive monitoring, high sensitivity, and long-term monitoring. It can realize real-time, online, and quantitative monitoring of the interface state of the steel and concrete composite structure, which is of great significance for improving the safety and reliability of the structure.

[0021] Specifically, in this embodiment, the quantitative monitoring system of the interface bonding state of the steel-concrete composite structure reserves a small hole on the steel component module 1, passes a thin steel bar through and pre-buries it in the concrete 2, avoiding the operation of additional drilling or damaging the structure, and meeting the requirements of non-destructive monitoring; when the concrete 2 is initially set, the soft sleeve 6 is pulled out to prevent the steel component module 1 from affecting the relative movement of the steel bar 5. And ensure that its hole diameter is slightly larger than the diameter of the steel bar 5, so as to ensure that the steel bar 5 can be integrated with the concrete 2, and the steel component module 1 will not affect the movement of the steel bar 5. Then, the gap between the steel bar 5 and the small hole is filled with a soft sleeve 6 of appropriate size to prevent the concrete 2 from flowing out.

[0022] The electromagnetic induction probe 3 is integrated with the steel bar 5 inserted into the concrete 2 through the connecting plate 4, and the steel bar 5 is moved by the contraction of the concrete 2, which ensures the safety and reuse of the electromagnetic induction probe 3 and avoids damage caused by movement or stress. The electromagnetic induction probe 3 points to the steel component module 1 and is placed vertically to the surface of the steel component module 1. The probe maintains a certain distance from the surface of the steel component module 1 and is in a non-contact state.

[0023] Finally, the impedance of the electromagnetic induction probe 3 is measured online in real time through the dynamic data collector 10. Based on the quantitative relationship between the impedance of the electromagnetic induction probe 3 obtained by calibration and the change in the distance between it and the steel component module 1, the quantitative result of the interface bonding state or the degree of peeling expressed by the relative displacement between the interfaces is obtained, and the long-term interface state between the steel component module 1 and the concrete 2 is obtained. In short, the system can directly output the voltage change of the electromagnetic current induction probe 3 as relative displacement data to achieve real-time, online monitoring.

[0024] The control component is configured to implement the following steps by executing a computer program stored therein: S1, acquiring the detection data collected by the electromagnetic induction eddy current detection component, and calculating and processing the detection data according to the response equation to obtain the equivalent impedance of the eddy current in the steel and concrete composite component; Specifically, step S1 includes: the mathematical expression of the response equation is: ,in, In order to ignore the resistance of the electromagnetic induction probe coil during electromagnetic induction eddy current measurement, In order to ignore the inductance of the electromagnetic induction probe coil during electromagnetic induction eddy current measurement, is the angular frequency of the excitation signal, is the equivalent mutual inductance between the coil and the eddy current loop, is the equivalent resistance of electromagnetic induction in the steel component module, is the equivalent inductance of electromagnetic induction in the steel component module, is the first-order derivative of the excitation current, is the first-order derivative of the exciting eddy current, is the excitation voltage at both ends of the electromagnetic induction probe coil; The response equation is solved to obtain the equivalent impedance of the electromagnetic induction probe coil after the steel component module is introduced, and the expression is: ,in, is the equivalent impedance, is the mutual inductance coefficient, p and q are both coefficients of coil parameters, and d is the distance between the steel component module and the electromagnetic induction probe.

[0025] In this embodiment, the response equation is solved to obtain the equivalent impedance of the electromagnetic induction probe coil after the conductor to be measured introduced into the steel and concrete composite component, that is, the steel component module 1.

[0026] S2, simplifying the equivalent impedance, and obtaining an interface monitoring result based on the simplified equivalent impedance, wherein the equivalent impedance is only affected by the distance d between the steel and concrete composite component and the electromagnetic induction eddy electric detection component.

[0027] Specifically, step S2 includes: simplifying the equivalent impedance, and the mathematical expression of the simplified equivalent impedance is: ; According to the simplified equivalent impedance, a quantitative relationship between the change in relative displacement between the steel component module and the detection head of the electromagnetic induction probe and the equivalent impedance is established to generate an interface monitoring result.

[0028] Specifically, in this embodiment, generally, R c The value of is very small; when the angular frequency of the excitation signal is high, the equivalent impedance can be simplified by introducing the steel component module 1 in the steel and concrete composite component as the conductor to be measured. a 、Inductance L a and angular frequency Therefore, the equivalent impedance of the electromagnetic induction probe coil is mainly affected by the distance d between the conductor being measured, that is, the steel component module in the steel-concrete composite structure and the probe.

[0029] The impedance of the electromagnetic induction probe is measured by a dynamic data acquisition instrument. According to the relationship between the equivalent impedance of the electromagnetic induction probe coil and the distance d between the steel component and the probe in the steel-concrete composite structure, the relative displacement of the interface between the steel component module 1 and the concrete 2 is directly obtained, thereby reflecting the quantitative expression of the interface state or peeling degree between the steel component module 1 and the concrete 2. When the internal concrete and the inner surface of the steel component are peeled off, the concrete 2 drives the steel bar 5 to move, thereby changing the output signal of the electromagnetic induction probe 3, and the distance between the electromagnetic induction probe 3 and the outer surface of the steel component module 1 is reduced. The reduction amount is the interface peeling amount. Therefore, the relative displacement between the electromagnetic induction probe 3 and the steel component module 1 represents the relative displacement between the concrete 2 and the internal interface of the steel component module 1, thereby achieving the purpose of real-time, online, and quantitative monitoring of the interface bonding state and peeling degree of the steel-concrete composite structure.

[0030] During the measurement process, an alternating magnetic field is generated in the coil of the electromagnetic induction probe. When the steel plate (metal material) to be measured is close to this magnetic field, an induced current is generated on the surface of the steel component module 1. At the same time, the eddy current field also generates an alternating magnetic field in the opposite direction of the head coil. Due to its reaction, the amplitude and phase of the high-frequency current of the head coil are changed, thereby changing the effective impedance of the coil and the voltage amplitude. Since the relative displacement between the head of the electromagnetic induction probe and the steel component module 1 causes a change in voltage, the relative displacement of the steel component module 1 and the electromagnetic induction probe can be measured by establishing the relationship between the relative displacement and the output voltage.

[0031] In brief, see Figure 1 , an electromagnetic induction probe 3 is installed on a 1000mm×1000mm×1500mm square steel tube concrete component to conduct long-term monitoring of the debonding defect between the steel plate and the concrete interface. In order not to damage the main structure, one end of the steel bar 5 is inserted into the concrete 2 through the exhaust hole of the component, and the electromagnetic induction probe 3 is connected to the outer end of the steel bar 5 through the connecting plate 4. Please refer to Figure 4 When the concrete 2 shrinks and deforms, it drives the steel bar 5 to move relative to the inner wall of the steel component module 1, which will bring the electromagnetic induction probe 3 closer to the outer surface of the steel component module 1, thereby changing the distance between the probe and the outer wall of the steel component module 1. As the distance between the outer wall of the steel component module 1 and the electromagnetic induction probe 3 gets closer, the overcurrent loss will become larger and the oscillation amplitude will become smaller. The oscillation amplitude is rectified and then used as a change in DC voltage. By measuring the change in this distance, quantitative, real-time, and non-contact monitoring of the interface peeling between the concrete 2 and the inner surface of the steel component module 1 can be achieved.

[0032] See also Figures 5 to 7 In summary, the quantitative monitoring system for the interfacial bonding state of the steel-concrete composite structure can implement non-destructive, highly sensitive, real-time, long-term, online, contactless and quantitative monitoring of the interfacial peeling state of the steel-concrete composite structure. Specifically, the system makes full use of the characteristic that the steel in the steel-concrete composite structure generates current under the action of the alternating magnetic field to design an electromagnetic induction probe. By using the electromagnetic induction probe, the eddy current generated on the steel plate responds to the inductance and impedance of the electromagnetic induction probe, and the change in the distance between the electromagnetic induction probe and the steel plate is obtained to reflect the bonding state or peeling state of the interface for quantitative monitoring.

[0033] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A quantitative monitoring system for the interface bonding state of a steel and concrete composite structure, characterized in that: include: A control component, a steel and concrete composite component, a fixing component, and an electromagnetic induction eddy electric detection component, wherein a data end of the control component is electrically connected to a data end of the electromagnetic induction eddy electric detection component, and the electromagnetic induction eddy electric detection component is arranged on the steel and concrete composite component through the fixing component; The control component is configured to implement the following steps by executing a computer program stored therein: Acquire the detection data collected by the electromagnetic induction eddy-electric detection component, and calculate and process the detection data according to the response equation to obtain the equivalent impedance of the electromagnetic induction probe in the electromagnetic induction eddy-electric measurement of the steel and concrete composite component; The equivalent impedance is simplified, and an interface monitoring result is obtained based on the simplified equivalent impedance, wherein the equivalent impedance is only affected by the distance d between the steel and concrete composite component and the electromagnetic induction eddy electric detection component.

2. The quantitative monitoring system for the interface bonding state of a steel-concrete composite structure according to claim 1 is characterized in that: The steel and concrete composite component comprises a steel component module and concrete. The concrete is poured in the steel component module. A vent hole is provided on a first end surface of the steel component module.

3. The quantitative monitoring system for the interface bonding state of a steel-concrete composite structure according to claim 2 is characterized in that: The fixing assembly includes a steel bar, a soft sleeve, and a first nut. The soft sleeve is movably clamped on the exhaust hole. The first end of the steel bar passes through the soft sleeve and is cast in the steel component module together with the concrete. The electromagnetic induction eddy current detection assembly is configured at the second end of the steel bar through the first nut.

4. The quantitative monitoring system for the interfacial bonding state of a steel-concrete composite structure according to claim 3 is characterized in that: The electromagnetic induction eddy electric detection assembly includes an electromagnetic induction probe, a connecting plate, and a second nut. The first end of the connecting plate is configured on the second end of the steel bar through the first nut, and the electromagnetic induction probe is configured on the second end of the connecting plate through the second nut. The electromagnetic induction probe is perpendicular to the first end face of the steel component module, wherein the detection head of the electromagnetic induction probe faces the steel and concrete composite component and there is a preset distance. The electromagnetic induction probe is configured to measure the relative displacement change between the steel component module and the detection probe under static conditions or dynamic conditions.

5. The quantitative monitoring system for the interfacial bonding state of a steel-concrete composite structure according to claim 4 is characterized in that: The monitoring accuracy of the electromagnetic induction probe is 5×10 -4 mm.

6. The quantitative monitoring system for the interfacial bonding state of a steel-concrete composite structure according to claim 4 is characterized in that: The control component includes a controller, a dynamic data collector, a three-way output switching power supply, and a transmission line. The output end of the three-way output switching power supply is electrically connected to the power supply end of the electromagnetic induction probe and the power supply end of the dynamic data collector. The electromagnetic induction probe is electrically connected to the dynamic data collector through the transmission line, and the data end of the dynamic data collector is electrically connected to the data end of the controller.

7. The quantitative monitoring system for the interfacial bonding state of a steel-concrete composite structure according to claim 2 is characterized in that: The detection data is calculated and processed according to the response equation to obtain the equivalent impedance of the eddy current in the steel and concrete composite member, which is specifically: The mathematical expression of the response equation is: ,in, In order to ignore the resistance of the eddy current induction probe coil during electromagnetic induction eddy current measurement, In order to ignore the inductance of the eddy current induction probe coil during electromagnetic induction eddy current measurement, is the angular frequency of the excitation signal, is the equivalent mutual inductance between the coil and the eddy current loop, is the equivalent resistance of eddy current in the steel component module, is the equivalent inductance of the eddy current in the steel component module, is the first-order derivative of the excitation current, is the first-order derivative of the exciting eddy current, is the excitation voltage across the eddy current probe coil; The response equation is solved to obtain the equivalent impedance of the electromagnetic induction probe coil after the steel plate module is introduced, and the expression is: ,in, is the equivalent impedance, is the mutual inductance coefficient, p and q are both coefficients of coil parameters, and d is the distance between the steel component module and the electromagnetic induction probe.

8. The quantitative monitoring system for the interfacial bonding state of a steel-concrete composite structure according to claim 7 is characterized in that: The equivalent impedance is simplified, and based on the simplified equivalent impedance, the interface monitoring result is obtained, specifically: The equivalent impedance is simplified, and the mathematical expression of the simplified equivalent impedance is: ; According to the simplified equivalent impedance, a quantitative relationship between the change in relative displacement between the steel component module and the detection head of the electromagnetic induction probe and the equivalent impedance is established to generate an interface monitoring result.

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