Long-term real-time monitoring system and monitoring method for broken wire of in-service hollow slab bridge steel strand based on black hole waveguide rod

Abstract

The invention discloses an in-service hollow slab bridge steel strand broken wire long-term real-time monitoring system and monitoring method based on a black hole waveguide rod, and relates to the technical field of hollow slab bridge steel strand broken wire monitoring. Steel plates are arranged at the two ends of a hollow slab bridge in the transverse direction, and the waveguide rod is arranged on the steel plates installed on the hollow slab bridge in a bonding mode; longitudinally distributed waveguide rods are connected with the waveguide rods arranged on the two sides of the hollow slab to form U-shaped distribution, black hole waveguide rods are installed at the two ends of the U-shaped waveguide rod structure, acoustic emission sensors are arranged at the two ends of the U-shaped waveguide rod structure, and a monitoring terminal is connected with the acoustic emission sensors to receive acoustic emission signals; through the overall structure design and the monitoring method, long-term real-time monitoring of the whole hollow slab bridge can be realized, through improvement of the structure, the overall performance reduction risk of the system is effectively reduced, the long-term stability and maintainability of the monitoring system are ensured, and meanwhile, the complexity of arrangement of hollow slab bridge sensors and the system cost are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of civil engineering structure health monitoring, and in particular to a wire breakage monitoring system and method for a hollow slab bridge steel strand. Background Art

[0002] In the actual operation of bridges, prestressed steel strands are the lifeline of in-service concrete hollow slabs, and they are prone to damage such as stress concentration, corrosion and wire breakage of steel strands due to improper construction and environmental effects. Real-time long-term health monitoring, assessment and early warning of their safety status are very important. For old hollow slab bridges with a long service life, damage is prone to occur near the supports at both ends of the bridge, mainly because the support area is subjected to large stress and deformation, which is prone to stress concentration. In addition, the vicinity of the supports is often exposed to humid environments, especially when there are cracks, and moisture can easily penetrate into the concrete or around the steel bars. This leads to corrosion of steel bars and steel strands, especially in humid environments. Rusting of steel bars will weaken the structural strength and increase the risk of bridge damage. Traditional bridge health monitoring technology mainly monitors indirect physical quantities such as displacement, strain, acceleration, etc., and cannot directly monitor structural damage, making it difficult to process massive data in the later stage. Large-scale, low-cost monitoring. Acoustic emission technology has unique advantages in health monitoring. It can achieve large-scale monitoring without the need for traffic control. It is more sensitive to minor damage and can promptly detect broken wire signals in steel strands. It can achieve online real-time assessment of health status. Acoustic emission technology can be used to achieve low-cost monitoring of the entire bridge cable.

[0003] Acoustic emission technology is a passive nondestructive testing method. Acoustic emission equipment usually includes sensors, amplifiers, acoustic emission collectors and acoustic emission signal output devices. Acoustic emission sensors are highly sensitive, and their surfaces are composed of piezoelectric ceramics, which can convert elastic waves into electrical signals; one end of the amplifier is connected to the sensor, and the other end is connected to the acoustic emission collector, the purpose of which is to amplify the acoustic emission signal; the acoustic emission collector can collect the waveform of the damage signal, and the waveform information contains all the damage signal information; the acoustic emission collector is connected to the computer, and the acoustic emission waveform or parameters can be output on the computer to analyze the damage information. Damage to the material will cause deformation, and deformation will produce elastic waves. When the material is damaged, it also means the release of elastic waves. The elastic waves will be collected by the acoustic emission sensor, and then converted into electrical signals, which will be amplified by the amplifier and recorded by the acoustic emission collector. Acoustic emission technology has been widely used in concrete structures, geotechnical structures, steel, composite materials, brick masonry structures, wood and other fields, and has achieved certain results in these fields. However, facing the current problems of complex layout and difficult maintenance of the acoustic emission monitoring system, especially in long-span bridges, the problems of signal attenuation and transmission stability are further aggravated. Therefore, how to improve the aggregation and conduction efficiency of acoustic wave signals and reduce the complexity of sensor layout has become a key problem in the current bridge monitoring field.

[0004] In view of the above, the present application provides a long-term real-time monitoring method for broken wires of in-service hollow slab bridge steel strands based on a black hole waveguide rod to solve the above problems. Summary of the invention

[0005] In order to overcome the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a long-term real-time monitoring method for broken wires of steel strands in service hollow slab bridges based on black hole waveguide rods, which is mainly used for damage detection in bridge structures. It aims to realize the monitoring of broken wire events of steel strands in the entire span of hollow slab bridges through structural improvements and signal enhancement means, reduce system complexity, and ensure the stability of long-distance transmission.

[0006] A long-term real-time monitoring system for broken wires of in-service hollow slab bridge steel strands based on a black hole waveguide rod, characterized by comprising: Multiple steel plates arranged at both ends of the hollow slab bridge are fixed to the bottom of the hollow slabs at both ends to provide signal aggregation and conduction paths along both ends of the bridge, and provide a support foundation for the subsequent installation of waveguide rods to ensure signal conduction; Waveguide rods are installed at the bottom of the steel plate and are distributed transversely along the bridge span, wherein the waveguide rods are arranged on the steel plate installed on the hollow plate bridge, and the waveguide rods arranged on both sides of the hollow plate are connected by longitudinally distributed waveguide rods to form a U-shaped distribution, and the waveguide rods are connected by connecting pieces to form a continuous waveguide structure; the waveguide rods are arranged at the black hole waveguide rods at both ends of the U-shaped waveguide rod structure, which are used to gather and enhance signals, reduce signal attenuation, and ensure that the sound wave signal can be transmitted over a long distance; The acoustic emission sensors arranged at both ends of the U-shaped waveguide rod structure are used to receive the acoustic emission signals after being concentrated and enhanced by the steel plate and the black hole waveguide rod, and transmit the signals to the monitoring terminal.

[0007] A method for long-term real-time monitoring of broken wires of in-service hollow slab bridge steel strands based on a black hole waveguide rod, deploying and utilizing the monitoring and positioning system to monitor and analyze broken wire acoustic signals, characterized in that it includes the following steps: S1: Steel plates are arranged and fixed in the transverse direction at both ends of the hollow slab bridge to form a gathering and conduction path for the sound wave signal; S2: Arrange the waveguide rods in sections and connect them through mechanical connectors. The waveguide rods are fixed to the bottom surface of the steel plate by bonding. The waveguide rods arranged on both sides of the hollow plate are connected by the longitudinally distributed waveguide rods to form a U-shaped distribution, forming a continuous waveguide structure to ensure the effective conduction of the acoustic emission signal. S3: Black hole waveguide rods are installed at both ends of the U-shaped waveguide rod structure to enhance and further focus the acoustic emission signal to ensure that the signal is transmitted to the sensors at both ends of the bridge structure; S4: Arrange and utilize acoustic emission sensors at both ends of the U-shaped waveguide rod structure to receive and detect the acoustic emission signals concentrated and conducted through the steel plate and enhanced by the black hole waveguide rod.

[0008] The beneficial effects of this technical solution are: (1) Through the overall structural design and monitoring method of the present invention, long-term real-time monitoring of hollow slab bridges can be achieved; (2) The waveguide rod is connected by a detachable sleeve connector, which is convenient for later maintenance and replacement, effectively reducing the risk of overall system performance degradation caused by factors such as corrosion of the waveguide rod material, thereby ensuring the long-term stability and maintainability of the monitoring system; (3) Since steel plates are set up in the system to gather acoustic wave signals, and black hole waveguide rods are installed at both ends of the waveguide rod for signal enhancement, it is only necessary to arrange an acoustic emission sensor at each end of the bridge structure to achieve long-term real-time monitoring of the entire hollow slab bridge, thereby reducing the complexity of sensor layout and system cost of the hollow slab bridge. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a schematic diagram of the overall process of the monitoring method of the present invention; Figure 2 It is a side view of the arrangement of monitoring points of the present invention; Figure 3 It is a transverse cross-sectional view of the monitoring point arrangement of the present invention; Figure 4 A top view of the monitoring point arrangement of the present invention; Figure 5 This is a position layout diagram of the acoustic emission collector of the present invention; Figure 6 A schematic top view perspective diagram of the arrangement position of the sensor of the present invention; Figure 7 It is a schematic diagram of the waveguide rod connecting piece of the present invention; Figure 8 This is a schematic diagram of the connection arrangement of the black hole waveguide rods of the present invention; Fig. 9 This is a schematic diagram of the black hole waveguide rod connecting piece of the present invention. DETAILED DESCRIPTION

[0010] The aforementioned and other technical contents, features and effects of the present invention will be clearly presented in the following detailed description of the embodiments with reference to the drawings of the present application. The structures and method contents mentioned in the following embodiments are all based on the drawings of the specification as reference.

[0011] The flowcharts used in this application are as follows Figure 1The operations implemented according to some embodiments of the present application are shown. In addition, those skilled in the art may add one or more other operations to the flowchart, or remove one or more operations from the flowchart under the guidance of the content of the present application.

[0012] A long-term real-time monitoring system for broken wires of in-service hollow slab bridge steel strands based on a black hole waveguide rod, which consists of the following components: like Figure 2 , Figure 5 As shown, multiple steel plates are arranged horizontally at both ends of the hollow slab bridge to provide a stable support foundation for the subsequent installation of the waveguide rod to ensure the high efficiency of signal transmission and also have the function of signal aggregation. Figure 7 As shown, a waveguide rod is arranged every 5 meters and connected by a detachable sleeve connector to form a continuous waveguide structure for easy later maintenance and replacement, effectively reducing the risk of overall system performance degradation caused by factors such as corrosion of the waveguide rod material, thereby ensuring the long-term stability and maintainability of the monitoring system.

[0013] The waveguide rod is fixed on the steel plate to avoid signal transmission failure caused by environmental vibration and temperature changes, so as to ensure efficient transmission of acoustic wave signals in the bridge span structure.

[0014] like Figure 8 , Fig. 9 As shown, black hole waveguide rods are installed at both ends of the U-shaped waveguide rod structure through black hole waveguide rod connectors to further gather and enhance the acoustic emission signal, thereby reducing the attenuation of the signal during long-distance transmission. Due to the role of the steel plate and the black hole waveguide rod, only one acoustic emission sensor is required at each end of the U-shaped waveguide rod structure to complete the end monitoring of the hollow plate bridge, which simplifies the sensor layout and reduces the system complexity and maintenance cost.

[0015] A method for long-term real-time monitoring of broken wires in in-service hollow slab bridge steel strands based on black hole waveguide rods. The working principles of each link are as follows: Figure 2 The specific description is as follows: Steel plate arrangement and fixation: Steel plates G are arranged and fixed in the transverse direction at both ends of the hollow slab bridge to form a gathering and efficient conduction path for the acoustic wave signal; Waveguide rod arrangement: The waveguide rod B is arranged in sections, connected by a detachable sleeve connector T, and bonded to the steel plate G to ensure effective conduction of the acoustic wave signal; Signal enhancement: Black hole waveguide rods H are installed at both ends of the continuous U-shaped waveguide structure to enhance and further concentrate the acoustic emission signal, ensuring that the signal can be transmitted to the sensors S at both ends of the U-shaped waveguide rod structure over a long distance.

[0016] Sensor signal reception: The acoustic emission sensors S arranged at both ends of the U-shaped waveguide rod structure are used to receive and detect the acoustic emission signals concentrated and conducted through the steel plate G and enhanced by the black hole waveguide rod H. When the steel strand X in the hollow plate breaks, the acoustic emission signal is transmitted to the sensor S along the steel plate G and the waveguide rod B.

[0017] The present invention can locate the lateral damage of the hollow slab bridge by calculating the time difference of the signals received by the two sensors. Signal time difference analysis is also a prior art. However, since the hollow slab bridge mainly relies on the arrangement of multiple sensors, this method has problems such as low positioning accuracy, complex system layout, and difficult maintenance. Especially in long-span bridges, the signal attenuation and transmission stability problems are further aggravated. Applying the existing damage location technology to the hollow slab bridge fully utilizes the characteristics of the hollow slab bridge and the hollow slab bridge acoustic emission monitoring system we have built, which significantly improves the accuracy and real-time performance of damage detection and meets the special needs of hollow slab bridge damage location.

[0018] Due to the signal aggregation and enhancement effect of the steel plate and the black hole waveguide rod, long-term real-time monitoring of the entire span of the bridge can be achieved by calculating only the signals received by two sensors.

[0019] The above description is only for illustrating the present invention. It should be understood that the present invention is not limited to the above embodiments, and various variations that conform to the concept of the present invention are within the protection scope of the present invention.

Claims

1. A long-term real-time monitoring system for broken wires of in-service hollow slab bridge steel strands based on a black hole waveguide rod, characterized in that: include: Multiple steel plates arranged at both ends of the hollow slab bridge are fixed to the bottom of the hollow slabs at both ends to provide signal aggregation and conduction paths along both ends of the bridge and provide a support foundation for the subsequent installation of waveguide rods to ensure signal conduction; Waveguide rods are installed on the bottom of the steel plate and are distributed transversely along the bridge span, wherein the waveguide rods are arranged on the steel plate installed on the hollow slab bridge, the ends of the waveguide rods are connected by waveguide rods to form a U-shaped distribution, and the waveguide rods are connected by connecting pieces to form a continuous waveguide structure; The black hole waveguide rods arranged at both ends of the U-shaped waveguide rod structure are used to further gather and enhance the signal, reduce signal attenuation, and ensure that the sound wave signal can be transmitted over a long distance; The acoustic emission sensors arranged at both ends of the U-shaped waveguide rod structure are used to receive the acoustic emission signals after being concentrated and enhanced by the steel plate and the black hole waveguide rod, and transmit the signals to the monitoring terminal.

2. According to claim 1, a black hole waveguide rod-based in-service hollow slab bridge steel strand broken long-term real-time monitoring system is characterized in that: The waveguide rod is fixed on the steel plate to ensure the stability of the signal conduction path between the waveguide rod and the steel plate, avoid signal conduction failure caused by environmental vibration and temperature change, and ensure that the sound wave signal is conducted in the bridge span structure.

3. A black hole waveguide rod-based long-term real-time monitoring system for broken wires of in-service hollow slab bridge steel strands according to claim 1 or 2, characterized in that: The waveguide rod adopts a segmented design and is connected by a sleeve connector, which is convenient for later maintenance and replacement.

4. A method for long-term real-time monitoring of broken wires in in-service hollow slab bridge steel strands based on a black hole waveguide rod, deploying and utilizing the monitoring and positioning system described in claims 1-3 to monitor and analyze broken wire acoustic signals, characterized in that: The following steps are involved: S1: Steel plates are arranged and fixed in the transverse direction at both ends of the hollow slab bridge to form a gathering and efficient conduction path for the sound wave signal; S2: Arrange the waveguide rods in sections and connect them through mechanical connectors. The waveguide rods are fixed to the bottom surface of the steel plate by bonding. The waveguide rods arranged on both sides of the hollow plate are connected by the longitudinally distributed waveguide rods to form a U-shaped distribution, forming a continuous waveguide structure to ensure the effective conduction of the acoustic emission signal. S3: Black hole waveguide rods are installed at both ends of the U-shaped waveguide rod structure to enhance and further concentrate the acoustic emission signal to ensure that the signal is transmitted to the sensors at both ends of the U-shaped waveguide rod; S4: Arrange and utilize acoustic emission sensors at both ends of the U-shaped waveguide rod structure to receive and detect the acoustic emission signals concentrated and conducted by the steel plate and enhanced by the black hole waveguide rod; S5: Perform time difference analysis on the signal at the monitoring terminal, and accurately locate the position of the hollow plate where the broken wire of the steel strand is located through the characteristic data of the received signal.

5. The method for long-term real-time monitoring of broken wires of in-service hollow slab bridge steel strands based on black hole waveguide rods according to claim 4 is characterized in that: In the S4, an acoustic emission sensor is arranged at each end of the U-shaped waveguide rod structure, and a steel plate is set in the system to gather the sound wave signal, and a black hole waveguide rod is installed at both ends of the U-shaped waveguide rod structure to enhance the signal. By calculating the time difference of the signals received by the two sensors, the specific hollow slab position corresponding to the broken wire of the steel strand is determined, thereby realizing the lateral damage positioning of the hollow slab bridge and reducing the complexity of the sensor arrangement and the system cost of the hollow slab bridge.

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