Method for detecting hinge pin of sling of suspension bridge

Abstract

The invention discloses a method for detecting a suspension bridge sling pin shaft and a bushing, and relates to the field of sling pin shaft detection.The method comprises the steps that a detection area is machined at the preset position of the bearing surface of the pin shaft, and a first sensing unit is arranged in the detection area and used for detecting the contact pressure state between the pin shaft and the bushing; a second sensing unit is embedded in the preset position of the inner wall of the bushing, the sensing surface of the second sensing unit is lower than the standard working inner surface of the bushing by a preset distance, and the second sensing unit is used for indirectly detecting the abrasion depth of the bushing; acquiring detection data of the first sensing unit and the second sensing unit in real time or periodically; and whether the stress states of the pin shaft and the bushing are abnormal or not is judged based on detection data of the first sensing unit. The method is used for solving the technical problem that in the prior art, real-time, online and direct stress state monitoring and abrasion degree evaluation cannot be conducted on a pin shaft-bush friction pair in a closed state, and therefore early warning and precise maintenance are difficult to achieve.

Description

Technical Field

[0001] This invention relates to the field of cable pin inspection, specifically a method for inspecting cable pins of suspension bridges. Background Technology

[0002] As one of the main forms of modern long-span bridges, suspension bridges rely heavily on their cable system, a crucial force-transmitting component connecting the main cable and the stiffening girder, directly impacting the overall safety and service life of the bridge. The upper and lower ends of the cables are typically connected to cable clamps and stiffening girder lugs via anchorages. To accommodate the complex relative displacements between the main cable and stiffening girder caused by live loads, wind loads, and temperature variations, a pin-and-bulb friction pair is commonly installed between the anchorages and the stiffening girder lugs. This friction pair, as the core hinge point, bears high-stress alternating loads and additional transverse loads over extended periods; its operational condition is of paramount importance.

[0003] For the inspection and condition assessment of the friction pairs between the cable pins and bushings of in-service suspension bridges, the industry lacks efficient and accurate online monitoring methods. Conventional practices mainly rely on periodic overhauls and maintenance, during which the cables are disassembled, and the pins and bushings are manually inspected visually, dimensionally measured, or surface-tested. In addition, some indirect detection methods based on vibration testing or acoustic emission exist, attempting to infer the health status of the connection nodes by analyzing changes in the structure's dynamic response. These methods either rely on predetermined maintenance cycles or require complex signal processing and experience-based judgment.

[0004] The aforementioned existing technologies have significant limitations. First, manual inspection requires traffic disruption and large-scale disassembly, resulting in high operating costs, long cycles, and difficulty in detecting early damage. Second, because the pin-bushing friction pair is always within a closed, invisible, and confined space, crucial information such as changes in internal stress state and wear progress cannot be directly obtained by the naked eye or conventional instruments. This makes it difficult to detect potential fatigue cracks, abnormal wear, and increased clearance in a timely manner. Often, problems only become apparent when wear intensifies, abnormal noises occur, or even component failure occurs. By this time, the structure may already pose a substantial threat to structural safety, and the cost of repair and replacement increases dramatically. Therefore, there is an urgent need in this field for an effective method that can monitor the stress state and wear degree of the pin-bushing friction pair in real time, online, and directly. Summary of the Invention

[0005] Based on this, the purpose of this invention is to provide a method for detecting suspension bridge cable pins, so as to solve the technical problem that the existing technology cannot perform real-time, online, and direct monitoring of the stress state and wear assessment of the pin-bushing friction pair in a closed state, thus making it difficult to achieve early warning and accurate maintenance.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for detecting suspension bridge cable pins, comprising the following steps: machining a detection area at a preset position on the bearing surface of the pin, and setting a first sensing unit within the detection area to detect the contact pressure state between the pin and the bushing; embedding a second sensing unit at a preset position on the inner wall of the bushing, wherein the sensing surface of the second sensing unit is lower than the standard working inner surface of the bushing by a predetermined distance, for indirectly detecting the wear depth of the bushing; acquiring the detection data of the first sensing unit and the second sensing unit in real time or periodically; determining whether the stress state between the pin and the bushing is abnormal based on the detection data of the first sensing unit, and determining whether the wear of the bushing has reached the replacement threshold based on the detection data of the second sensing unit.

[0007] The invention is further configured such that the second sensing unit is a miniature pressure sensor or a contact switch sensor, which is fixed in a pre-machined mounting hole in the inner wall of the bushing by means of interference fit, bonding or encapsulation; the predetermined distance is 1.5mm to 3.5mm.

[0008] The present invention is further configured such that the second sensing unit does not contact the pin shaft when the wear threshold is not reached, and when it begins to bear pressure, it indicates that the bushing material has been worn to the predetermined distance, at which point the system issues a warning or alarm that the bushing and pin shaft need to be replaced.

[0009] The present invention is further configured such that, in determining whether the stress state is abnormal based on the detection data of the first sensing unit, the following specific steps are included: a preset pressure threshold related to the bearing capacity and safety factor of the pin shaft design; when the real-time pressure value detected by the first sensing unit continuously exceeds the pressure threshold, or the dynamic change amplitude of the pressure is abnormal, the stress state is determined to be abnormal.

[0010] The present invention is further configured such that the detection data of the first sensing unit and the second sensing unit are transmitted to a data acquisition and processing system via wired or wireless transmission; the data acquisition and processing system stores, analyzes and displays the data.

[0011] The present invention is further configured such that the data acquisition and processing system integrates a data diagnostic algorithm, which is used to perform time-domain and frequency-domain analysis on the pressure data sequence of the first sensing unit to identify whether there are signs of deflection, jamming or fatigue damage in the pin shaft.

[0012] The present invention is further configured such that the data acquisition and processing system is also connected to a remote monitoring center and / or a mobile terminal, and when it is determined that the status is abnormal or the wear threshold is reached, maintenance alarm information is automatically generated and sent.

[0013] The present invention is further configured as a suspension bridge cable pin detection system for implementing the method of claim 1, characterized in that it comprises: a first sensing unit disposed on the pin for detecting contact pressure; a second sensing unit disposed on the inner wall of the bushing for detecting wear depth; a data acquisition module communicatively connected to the first and second sensing units; and a data processing and early warning module connected to the data acquisition module, configured to perform data analysis and threshold judgment, and generate status information and maintenance prompts.

[0014] In summary, the present invention has the following main beneficial effects:

[0015] This invention achieves online, real-time, and direct monitoring of the stress state and wear process of the pin-bushing friction pair under closed conditions by embedding a pressure film sensor at the pin shaft to monitor contact pressure in real time and pre-embedding an electronic sensor below the inner surface of the bushing to directly detect wear depth. This overcomes the lag and inaccuracy of traditional manual inspection and indirect detection. The method constructs a dual safety guarantee mechanism of "pressure anomaly early warning" and "wear limit judgment," enabling early detection of potential faults and providing accurate data support for predictive maintenance. This significantly improves the safety and operation and maintenance efficiency of the suspension bridge cable system, effectively extends the service life of components, and reduces the total life cycle cost. Attached Figure Description

[0016] Figure 1 This is a diagram illustrating the method steps of the present invention. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings, so that those skilled in the art can implement the present invention. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the scope of protection of the present invention.

[0018] This invention provides a method for inspecting suspension bridge cable pins. The core of this method lies in achieving real-time, online monitoring of the stress state and wear degree of the friction pair between the pin and the bushing by directly embedding sensors, thereby overcoming the lag of traditional manual inspection and the inaccuracy of indirect detection. The specific implementation of this method includes several key steps and components, which will be described in detail below.

[0019] A detection area is machined at a predetermined position on the bearing surface of the pin. This detection area is typically selected in the middle of the pin or a stress concentration area, as these parts bear the greatest load during bridge operation and are most prone to fatigue or abnormal wear. The detection area can be machined into an arc-shaped groove or a flat surface, and its size and shape must match the overall structure of the pin to ensure that it does not affect the pin's mechanical strength and normal operation. A first sensing unit is installed within the machined detection area. This first sensing unit is preferably a pressure diaphragm sensor, which is fixed to the arc-shaped groove or flat surface by bonding, embedding, or molding. During installation, it is necessary to ensure that the detection surface of the pressure diaphragm sensor smoothly transitions to the pin's surface contour to avoid additional stress concentration or interference during relative movement between the pin and the bushing, thereby ensuring the accuracy and reliability of the detection data. The first sensing unit is mainly used to detect the contact pressure state between the pin and the bushing in real time, and its output signal reflects the force condition of the friction pair.

[0020] A second sensing unit is embedded at a predetermined position on the inner wall of the bushing. The second sensing unit is preferably a miniature pressure sensor or a contact switch sensor, which is fixed in a pre-machined mounting hole in the inner wall of the bushing by interference fit, bonding, or encapsulation. During installation, the sensing surface of the second sensing unit must be lower than the standard working inner surface of the bushing by a predetermined distance. This predetermined distance is set according to the bushing material, design wear life, and safety requirements, and is typically 1.5mm to 3.5mm. This design ensures that the second sensing unit does not directly contact the pin before the bushing reaches its wear threshold, thus avoiding premature signal triggering or affecting the normal operation of the friction pair. When the bushing gradually wears down due to long-term use, and its inner wall material is worn to the predetermined distance, the pin begins to contact the sensing surface of the second sensing unit and applies pressure. At this time, the second sensing unit detects the pressure signal, indicating that the wear depth of the bushing has reached the replacement threshold, and the system immediately issues a warning or alarm that the bushing and pin need to be replaced. This indirect method of detecting wear depth effectively solves the problem of difficulty in directly measuring wear in enclosed spaces.

[0021] After the sensors are set up, the detection data from the first and second sensing units need to be acquired in real time or periodically. Data acquisition can be achieved through wired or wireless transmission, such as using cable connections or wireless radio frequency (RF) communication modules to send sensor signals to a data acquisition and processing system. The data acquisition and processing system is responsible for storing, analyzing, and displaying the received data. This system typically includes a data acquisition module, a data processing unit, a storage medium, and a user interface. The data acquisition module communicates with the first and second sensing units and is responsible for signal conditioning and conversion; the data processing unit analyzes and processes the data based on a preset algorithm; the storage medium records historical data for subsequent trend analysis; and the user interface displays real-time status and historical curves in graphical or numerical form, allowing maintenance personnel to intuitively understand the health status of the friction pair.

[0022] Determining whether the stress state of the pin and bushing is abnormal based on the detection data from the first sensing unit is a crucial aspect of this invention. The specific determination process includes: setting a preset pressure threshold, which is related to the pin's design load-bearing capacity, safety factor, and the actual working conditions of the bridge, and is typically determined based on engineering calculations and experimental data. When the real-time pressure value detected by the first sensing unit continuously exceeds this pressure threshold, or when the dynamic change amplitude of the pressure exhibits abnormalities (such as a sudden increase or oscillation), the data processing unit determines that the stress state is abnormal. This abnormality may indicate that the pin is at risk of deflection, jamming, or overload, requiring timely inspection and maintenance.

[0023] To further improve diagnostic accuracy, the data acquisition and processing system integrates a data diagnostic algorithm. This algorithm performs time-domain and frequency-domain analysis on the pressure data sequence of the first sensing unit. Time-domain analysis can identify the steady-state value and fluctuation characteristics of the pressure, while frequency-domain analysis extracts the frequency components of the pressure signal through methods such as Fourier transform, thereby identifying whether the pin has signs of deflection, jamming, or fatigue damage. For example, if a peak value of a specific frequency appears in the frequency domain, it may indicate that the pin has undergone periodic vibration or resonance, which is often a precursor to fatigue damage.

[0024] The data acquisition and processing system is also connected to a remote monitoring center and / or mobile terminals. When the system determines that the status is abnormal or wear has reached a threshold, it automatically generates and sends maintenance alarm information. The alarm information may include the specific fault type, location identifier, and suggested measures, and is pushed to the terminal devices of relevant maintenance personnel via network or SMS to achieve rapid response and accurate maintenance.

[0025] This invention also relates to a suspension bridge cable pin detection system for implementing the above-described method. The system includes a first sensing unit mounted on the pin, a second sensing unit mounted on the inner wall of a bushing, a data acquisition module communicatively connected to the first and second sensing units, and a data processing and early warning module connected to the data acquisition module. The data processing and early warning module is configured to perform data analysis and threshold judgment, and generate status information and maintenance prompts. The entire system adopts a modular design, facilitating installation and maintenance, and has good scalability, adapting to the monitoring needs of different bridge structures.

[0026] In summary, this invention achieves comprehensive, real-time monitoring of the suspension bridge cable pin-bushing friction pair by directly embedding sensors at key locations in the pin and bushing, combined with advanced data processing and communication technologies. This method not only enables early detection of potential faults but also provides reliable data support for predictive maintenance, significantly improving the safety and economy of bridge operation.

[0027] Although embodiments of the present invention have been shown and described, these specific embodiments are merely explanations of the invention and are not intended to limit it. The specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. After reading this specification, those skilled in the art may make modifications, substitutions, and variations to the embodiments as needed without departing from the principles and spirit of the invention, but such modifications, substitutions, and variations are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A method for detecting the pins of suspension cables in a suspension bridge, characterized in that, Includes the following steps: A detection area is machined at a preset position on the bearing surface of the pin, and a first sensing unit is set in the detection area to detect the contact pressure state between the pin and the bushing. A second sensing unit is embedded at a predetermined position on the inner wall of the bushing. The sensing surface of the second sensing unit is a predetermined distance below the standard working inner surface of the bushing, which is used to indirectly detect the wear depth of the bushing. The detection data of the first sensing unit and the second sensing unit are acquired in real time or periodically. Based on the detection data of the first sensing unit, it is determined whether the stress state of the pin and bushing is abnormal, and based on the detection data of the second sensing unit, it is determined whether the wear of the bushing has reached the replacement threshold.

2. The method for detecting the pin shaft of the sling cable of the suspension bridge according to claim 1, characterized in that: The process of machining a detection area at a preset position on the bearing surface of the pin specifically involves machining an arc-shaped groove or plane in the middle or stress concentration area of ​​the pin. The first sensing unit is a pressure film sensor, which is fixed in the arc-shaped groove or plane by bonding, embedding or molding, so that its detection surface smoothly transitions with the surface contour of the pin.

3. The method for detecting suspension bridge cable pins according to claim 1, characterized in that: The second sensing unit is a miniature pressure sensor or a contact switch sensor, which is fixed in a pre-machined mounting hole in the inner wall of the bushing by means of interference fit, bonding or encapsulation; the predetermined distance is 1.5mm to 3.5mm.

4. The method for detecting suspension bridge cable pins according to claim 3, characterized in that: The second sensing unit does not contact the pin before the wear threshold is reached. When it begins to bear pressure, it indicates that the bushing material has been worn to the predetermined distance. At this time, the system issues a warning or alarm that the bushing and pin need to be replaced.

5. The method for detecting suspension bridge cable pins according to claim 1, characterized in that: The step of determining whether the stress state is abnormal based on the detection data of the first sensing unit specifically includes: setting a pressure threshold related to the design bearing capacity and safety factor of the pin shaft; when the real-time pressure value detected by the first sensing unit continuously exceeds the pressure threshold, or the dynamic change amplitude of the pressure is abnormal, it is determined that the stress state is abnormal.

6. A method for detecting suspension bridge cable pins according to any one of claims 1 to 5, characterized in that: The detection data from the first and second sensing units are transmitted to a data acquisition and processing system via wired or wireless transmission; the data acquisition and processing system stores, analyzes, and displays the data.

7. The method for detecting suspension bridge cable pins according to claim 6, characterized in that: The data acquisition and processing system integrates a data diagnostic algorithm, which is used to perform time-domain and frequency-domain analysis on the pressure data sequence of the first sensing unit to identify whether there are signs of deflection, jamming or fatigue damage in the pin.

8. The method for detecting suspension bridge cable pins according to claim 6, characterized in that: The data acquisition and processing system is also connected to a remote monitoring center and / or a mobile terminal. When the system determines that the status is abnormal or the wear threshold has been reached, it automatically generates and sends maintenance alarm information.

9. A suspension bridge cable pin detection system for implementing the method of claim 1, characterized in that: include: The first sensing unit, mounted on the pin, is used to detect contact pressure. The second sensing unit, located on the inner wall of the bushing, is used to detect the wear depth. A data acquisition module that is communicatively connected to the first sensing unit and the second sensing unit; The data processing and early warning module, which is connected to the data acquisition module, is configured to perform data analysis and threshold judgment, and generate status information and maintenance prompts.

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