Effective prestress calibration method and monitoring device for high-speed rail continuous beam bridge

Abstract

The invention discloses an effective prestress calibration method and monitoring device for a high-speed rail continuous beam bridge, and belongs to the technical field of civil engineering structure health monitoring. The method aims to solve the problem that long-term and real-time monitoring cannot be carried out on the effective prestress of the prestressed structure in the service period in the prior art. According to the method, through dual calibration combining finite element analysis and field tensioning, a high-precision conversion relation from working anchor strain to effective prestress is established, and real-time calculation is carried out through the relation in the service period. The monitoring device comprises a sensing unit and a data processing unit. According to the invention, full-period, real-time and accurate monitoring of the effective pre-stress state is realized.

Description

Technical Field

[0001] This invention relates to the field of civil engineering structural health monitoring technology, and more specifically, to a long-term, real-time monitoring method and device for effective prestress in prestressed concrete structures, particularly a method and device for calibrating the effective prestress of a high-speed railway continuous beam bridge. Background Technology

[0002] Prestressing technology is a key means of improving the performance of concrete structures. Its core lies in using the pressure pre-applied by prestressing tendons to counteract the tensile stress under service loads. The actual effective prestress value remaining in the prestressing tendons is the most direct parameter for assessing the structural performance and safety status. Insufficient effective prestress may lead to structural cracking and excessive deformation, while excessive prestress may cause failure of the reinforcement or anchorages.

[0003] Currently, the control of effective prestress in engineering practice mainly relies on the dual control of internal force and elongation during the tensioning stage. However, this method has significant limitations: First, the tension at the tensioning end, after various losses (such as anchor retraction, friction, concrete shrinkage and creep), differs significantly from the actual effective prestress value established in the structure; second, traditional methods can only provide data at the instant of construction and cannot monitor changes in effective prestress caused by material degradation, fatigue loads, and environmental erosion over the decades-long service life of the structure; finally, loss estimation methods based on theoretical formulas lack accuracy and cannot meet the needs of modern engineering for refined and intelligent management and maintenance.

[0004] Therefore, there is an urgent need for a prestressed monitoring technology and device that can directly obtain signals from the prestressed anchorage zone and achieve high-precision, real-time, and effective prestressed monitoring throughout the entire lifecycle from construction to service. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies, this invention provides an effective prestress calibration method and monitoring device for high-speed railway continuous beam bridges, aiming to achieve accurate, continuous, and real-time tracking of the effective prestress state.

[0006] The principle of this invention is as follows: First, through finite element analysis, it is revealed that under two fundamentally different stress modes—tension (force on the free end) and service (force on the inner wall of the anchor hole)—there is a definite linear proportional relationship between the strain response and the resultant force of the working anchor. This proportional relationship is reflected in the sub-conversion coefficient λ of each cross-section. i Secondly, the absolute values ​​of the above theoretical relationships were calibrated through on-site tensioning to obtain the calibration coefficients of the actual structure. Finally, the theoretical proportional relationship was combined with the on-site absolute calibration to establish a reliable method for calculating the effective prestress during service life based on the monitored working anchor strain value.

[0007] In a first aspect, the present invention provides an effective prestress calibration method for high-speed railway continuous beam bridges, comprising the following steps: Calibration phase: S1. Based on the finite element model of the working anchor, obtain the corresponding data of simulated strain and simulated force of multiple preset sections under simulated tensioning and simulated service conditions. S2. Based on the simulation data, establish the first calibration relationship from simulated strain to simulated force for each section, and calculate an average conversion coefficient λ based on the first calibration relationship between the two working conditions. S3. During the actual prestressing tensioning process, measure the actual strain and total tension of each preset section, and establish a second calibration relationship between the actual strain and the total tension of each section. S4. Combining the conversion coefficient λ with the second calibration relationship, determine the third calibration relationship for service life monitoring; Monitoring phase: S5. During the service life of the structure, measure the real-time strain of each preset section, and calculate the current effective prestress value based on the third calibration relationship and the processed real-time strain.

[0008] Furthermore, in step S2, the method for calculating the conversion coefficient λ is as follows: for each cross-section, obtain the first coefficient under the tensioning condition from the first calibration relationship. and the second coefficient under service conditions Calculate the sub-transformation coefficient of this cross-section. The average conversion coefficient is obtained by averaging the sub-conversion coefficients of all cross sections. This design establishes a bridge for the conversion of strain-force relationships under two different stress modes through numerical simulation. Its beneficial effect is that it links the anchor force during service life, which is difficult to measure directly, with the tension force, which is easy to simulate, thus laying a theoretical foundation for subsequent field calibration.

[0009] Furthermore, the preset cross-sections are three in number, located at the center of the working anchor axis, near the tensioning end, and near the anchoring end, respectively. The advantages of this arrangement are: the strain distribution at the center cross-section is uniform and representative; the tensioning end cross-section is sensitive to the reaction force of the tensioning equipment; and the anchoring end cross-section directly senses the force of the anchor clamps. The combination of these three aspects comprehensively reflects the overall stress state of the working anchor, and the average calculation effectively offsets errors caused by local stress concentration, significantly improving the representativeness and reliability of the monitoring results.

[0010] Furthermore, the first and second calibration relationships are established through linear fitting. Their specific functional relationships can be: and (Simulated data), with and (measured tension data). The advantage of using linear fitting is that its model is simple, its physical meaning is clear (it holds true within the elastic range of the material), and the slope obtained from the fitting ( , , The calibration coefficient is a stable calculation process that is convenient for engineering applications.

[0011] Furthermore, in step S5, the processed real-time strain refers to the strain value after temperature drift correction of the measured real-time strain.

[0012] Furthermore, the temperature drift correction is achieved through the following steps: S51. Set a reference anchor that is made of the same material and in the same environment as the measured working anchor, but is not subjected to any force; S52. Obtain the reference strain of the reference anchor at the same position as the measured working anchor; S53. Subtract the corresponding reference strain from the real-time strain to obtain the strain value after temperature drift correction.

[0013] By setting up a physical reference anchor for differential measurement, the influence of ambient temperature changes on strain gauge readings and the sensor's own time drift can be almost completely eliminated, thus ensuring the accuracy and stability of long-term monitoring data, which is the key to achieving long-term reliable monitoring.

[0014] Furthermore, the strain of each preset cross-section is measured by at least four strain sensors evenly arranged circumferentially on that cross-section, and the average value of the readings of the at least four strain sensors is taken as the strain value of that cross-section. The circumferential multi-point arrangement and average value calculation can effectively eliminate the uneven strain distribution caused by the eccentric arrangement of prestressed tendons or local defects, making the measured cross-sectional strain value more representative of its overall average mechanical behavior and further improving the monitoring accuracy.

[0015] The present invention also provides an effective prestress monitoring device for high-speed railway continuous beam bridges, used to implement the method, comprising: The sensing unit is configured on multiple preset sections of the working anchor to collect strain signals; A data processing unit, communicatively connected to the sensing unit, is configured to: Store the average conversion coefficients obtained from finite element analysis. ; During the calibration phase, a second calibration relationship is established based on the data collected by the sensing unit during the tensioning process, and a third calibration relationship is obtained by calculation. During the monitoring phase, the effective prestress value is calculated and output based on the real-time strain data collected by the sensing unit and the third calibration relationship.

[0016] Furthermore, the sensing unit also includes a temperature compensation sensor deployed on the reference anchor; the data processing unit is further configured to: use the data from the temperature compensation sensor to perform temperature drift correction on the real-time strain data collected from the working anchor.

[0017] Furthermore, the sensor and circuitry in the sensing unit are externally protected by a layered protective structure, which includes a sealing layer, a buffer layer, and an outer protective shell arranged sequentially from the inside out. This triple protection system provides physical protection, environmental isolation (moisture-proof and corrosion-proof), and stress buffering for the fragile sensor and circuitry, greatly improving the durability and lifespan of the monitoring device in harsh environments and ensuring the feasibility of long-term monitoring.

[0018] Compared with the prior art, the present invention has the following beneficial effects: 1. Real-time monitoring of the entire lifecycle from construction to service has been achieved: A dual calibration strategy combining "theoretical proportional relationship calibration" and "on-site absolute value calibration" has been creatively proposed, and a reliable and universally applicable conversion relationship between the easily measurable strain of the working anchor and the effective prestress has been established for the first time. This makes it possible to continuously, in real-time, and digitally monitor the effective prestress state of key components, covering the entire lifecycle from tensioning construction to long-term service.

[0019] 2. The integration of multiple technologies significantly improves monitoring accuracy and long-term reliability: ① Spatial dimension: Multi-section layout and averaging calculation suppress local stress concentration and random errors; ② Environmental dimension: High-precision temperature drift self-compensation is achieved through the physical reference anchor differential method, fundamentally ensuring the long-term stability of the data; ③ Monitoring device dimension: A layered protection system ensures the long-term survivability of the sensing unit in harsh environments. These multiple dimensions collectively ensure high accuracy and high reliability of the monitoring data.

[0020] 3. Strong engineering applicability, with good feasibility and maintainability: The method and principle are clear, and the steps are standardized; the monitoring device is highly integrated and automated. The sensor deployment scheme and protection design fully consider the actual conditions and constraints of the engineering site, facilitating construction, installation, and subsequent maintenance, and has broad prospects for engineering promotion and application. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein: Figure 1 This is a flowchart of the effective prestress calibration and monitoring method of the present invention.

[0022] Figure 2 This is a typical front view of the working anchor construction.

[0023] Figure 3 for Figure 2 AA sectional view.

[0024] Figure 4 This is a finite element model diagram of the working anchor.

[0025] Figure 5 Applying surface loads to the working anchor finite element model under working condition. A schematic diagram.

[0026] Figure 6 Applying surface loads to the working anchor finite element model under load condition two. A schematic diagram.

[0027] Figure 7 The finite element model of the working anchor was loaded under the working condition. Strain cloud map.

[0028] Figure 8 The finite element model of the working anchor was completed under load condition two. Strain cloud map.

[0029] Figure 9 This is a structural diagram of the strain testing device of the present invention.

[0030] Figure 10 This is a schematic cross-sectional view of the layered protection system.

[0031] Figure 11 A schematic diagram of assembling a polypropylene protective shell for the working anchor section.

[0032] Figure 12 This is a schematic diagram of the connection between adjacent polypropylene protective shells.

[0033] Figure 13 for Figure 14 Top view.

[0034] Figure 14 The figure shows the fitting of numerical calibration coefficients for the first working anchor section under working condition one.

[0035] Figure 15 The figure shows the fitting of numerical calibration coefficients for the first working anchor section under working condition two.

[0036] Figure 16 The figure shows the fitting of numerical calibration coefficients for the second working anchor section under working condition one.

[0037] Figure 17 The figure shows the fitting of numerical calibration coefficients for the second working anchor section under working condition two.

[0038] Figure 18 The figure shows the fitting of numerical calibration coefficients for the third working anchor section under working condition one.

[0039] Figure 19 The figure shows the fitting of the numerical calibration coefficients for the third working anchor section under working condition two.

[0040] Figure 20 This is a fitting diagram of the measured calibration coefficients for the first working anchor section under working condition one.

[0041] Figure 21 This is a fitting diagram of the measured calibration coefficients for the second working anchor section under working condition one.

[0042] Figure 22 This is a fitting diagram of the measured calibration coefficients for the third working anchor section under working condition one.

[0043] Figure 23 The graph shows the change of effective prestress during service life with age of the measured working anchor 1 after processing by the method of this invention.

[0044] Figure 24 The graph shows the change in effective prestress during service life as a function of age, obtained by processing the working anchor 2 using the method of this invention.

[0045] Figure 25 This is a structural block diagram of the monitoring device of the present invention. Detailed Implementation

[0046] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] The terms "first," "second," etc., used in the specification and claims of this invention are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0048] This invention provides an effective prestress calibration method for high-speed railway continuous beam bridges, comprising the following steps: Calibration phase: S1. Based on the finite element model of the working anchor, obtain the corresponding data of simulated strain and simulated force of multiple preset sections under simulated tensioning and simulated service conditions. S2. Based on the simulation data, establish the first calibration relationship from simulated strain to simulated force for each section, and calculate an average conversion coefficient λ based on the first calibration relationship between the two working conditions. S3. During the actual prestressing tensioning process, measure the actual strain and total tension of each preset section, and establish a second calibration relationship between the actual strain and the total tension of each section. S4. Combining the conversion coefficient λ with the second calibration relationship, determine the third calibration relationship for service life monitoring; Monitoring phase: S5. During the service life of the structure, measure the real-time strain of each preset section, and calculate the current effective prestress value based on the third calibration relationship and the processed real-time strain.

[0049] In step S2, the method for calculating the conversion coefficient λ is as follows: for each cross section, obtain the first coefficient under the tensioning condition from the first calibration relationship. and the second coefficient under service conditions Calculate the sub-transformation coefficient of this cross-section. The average conversion coefficient is obtained by averaging the sub-conversion coefficients of all cross sections. .

[0050] The preset cross-sections are three, located at the center of the working anchor axis, near the tensioning end, and near the anchoring end, respectively.

[0051] The first calibration relationship and the second calibration relationship are established through linear fitting.

[0052] In step S5, the processed real-time strain refers to the strain value after temperature drift correction of the measured real-time strain.

[0053] The temperature drift correction is achieved through the following steps: S51. Set a reference anchor that is made of the same material and in the same environment as the measured working anchor, but is not subjected to any force; S52. Obtain the reference strain of the reference anchor at the same position as the measured working anchor; S53. Subtract the corresponding reference strain from the real-time strain to obtain the strain value after temperature drift correction.

[0054] The strain of each of the preset cross sections is measured by at least four strain sensors uniformly arranged circumferentially on the cross section, and the average value of the readings of the at least four strain sensors is taken as the strain value of the cross section.

[0055] The present invention also provides an effective prestress monitoring device for high-speed railway continuous beam bridges, used to implement the method, comprising: The sensing unit is configured on multiple preset sections of the working anchor to collect strain signals; A data processing unit, communicatively connected to the sensing unit, is configured to: Store the average conversion coefficient λ obtained based on finite element analysis; During the calibration phase, a second calibration relationship is established based on the data collected by the sensing unit during the tensioning process, and a third calibration relationship is obtained by calculation. During the monitoring phase, the effective prestress value is calculated and output based on the real-time strain data collected by the sensing unit and the third calibration relationship.

[0056] The sensing unit also includes a temperature compensation sensor deployed on the reference anchor; the data processing unit is further configured to: use the data from the temperature compensation sensor to perform temperature drift correction on the real-time strain data collected from the working anchor.

[0057] The sensor and circuitry in the sensing unit are externally protected by a layered protective structure, which includes a sealing layer, a buffer layer, and an outer protective shell arranged sequentially from the inside out.

[0058] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings and examples.

[0059] Example 1: Specific Implementation of the Monitoring Method This embodiment takes the working anchor of a side span of a prestressed concrete bridge as an example, combined with... Figure 1 The overall flowchart shown details the implementation process of this method. In this embodiment, test anchor 1 and test anchor 2 are set, model M15-6, material 40Cr, and axial length b=47mm.

[0060] 1. Calibration Phase Step S1: Modeling and Simulation Data Extraction First, based on the precise geometric dimensions of the working anchor (such as...) Figure 2 Based on the material properties (elastic modulus 210 GPa, Poisson's ratio 0.3), a three-dimensional linear elastic finite element model was established in ABAQUS software (as shown). Figure 4 As shown in the figure, a reasonable mesh is generated. Through refined finite element modeling, the elastic response of the working anchor under complex stress conditions can be accurately simulated, providing a reliable foundation for establishing accurate strain-force theoretical relationships.

[0061] Three preset sections are defined in the model (e.g.) Figure 3 , Figure 11As shown): Section 1 (23.5mm from the free end, axial center), Section 2 (4.7mm from the free end, near the tensioning end), Section 3 (4.7mm from the fixed end, near the anchoring end). The three-point layout covers the key areas of the working anchor's stress gradient, and the combined approach can more comprehensively reflect the overall stress state, avoiding the one-sidedness of single-point measurements.

[0062] Simulate two working conditions: Working condition 1 (simulated tensioning, such as...) Figure 5 As shown): A uniform surface load is applied to the free end face of the anchor. This simulates the reaction force of a tensioning jack. Calculations based on the design tension: ; in =6 (number of prestressed steel strands). =1395MPa (tension control stress). =140mm² (cross-sectional area of ​​a single prestressed steel strand). =7316mm² (total surface area of ​​the free end of the working anchor).

[0063] Operating Condition 2 (Simulated Service, such as...) Figure 6 (As shown): Apply a surface load to the inner wall of the conical hole of the anchor. The radial compressive stress transmitted by the clamping piece is simulated. The calculation takes into account the channel friction and the cone angle: ; in =13.5mm (large anchor hole radius), =6.25mm (small anchor hole radius). =47.24mm (generatrix length of the conical hole contact surface). =6°40' (cone angle of working anchor hole). =0.2 (coefficient of friction).

[0064] By simulating two different loading methods, the difference in the stress mechanism of the same working anchor during the tensioning period and the service period was revealed, which is the premise for establishing the conversion relationship between the two.

[0065] Finite element analysis was used to extract the average equivalent strain (simulated strain) of each cross section under two working conditions. , ) and the axial resultant force (simulated force) borne by the cross section or Loading complete. Strain cloud diagram as follows Figures 7-8 As shown.

[0066] Step S2: Calculate the numerical calibration coefficients and conversion coefficients λ For each cross section i ( i =1, 2, 3), respectively, the two sets of simulation data ( , )and( , Linear regression analysis was performed.

[0067] For condition one, the fitting formula is: The resulting slope This is the first coefficient of the cross section under simulated tensioning conditions.

[0068] For condition two, the fitting formula is: The resulting slope This is the second coefficient of the cross section under simulated service conditions.

[0069] Fitting examples are as follows Figures 14-19 As shown, linear fitting simplifies the model, has a clear physical meaning within the elastic range, and the obtained slope coefficient is stable, which is convenient for engineering applications.

[0070] Calculate the sub-transformation coefficients for each section: .

[0071] Finally, calculate the average conversion factor: The conversion factor Numerical simulations established the proportional relationship between calibration coefficients under tension and service conditions, which is a key bridge parameter that "maps" easily obtained field tension calibration results to service conditions that are difficult to calibrate directly. Through numerical simulations, the proportional characteristics of the strain response relationship of the working anchor under two drastically different stress states were obtained in advance, avoiding the difficulty of directly applying known loads for calibration during service.

[0072] Step S3: Obtain the measured tension calibration coefficient At the actual working anchor sections 1, 2, and 3, strictly follow... Figure 9 As shown, four BX120-3AA type foil resistance strain gauges 102 (90-degree symmetrical) are circumferentially bonded to each cross-section. All strain gauges are connected to a high-precision strain acquisition instrument 111 via shielded wires 103. The circumferential arrangement of multiple gauges and the averaging of values ​​can effectively compensate for strain measurement deviations caused by prestressing tendon eccentricity or local material inhomogeneity, thereby improving the representativeness of the cross-sectional strain values.

[0073] During the tensioning of prestressed steel strands, the following should be recorded simultaneously: ① Total tension force from the jack hydraulic pressure sensor, after calibration. ② Calculate the readings of four strain gauges on each cross-section and the average measured strain of that cross-section. .

[0074] For each cross section The data under multi-stage tension are compared ( , Perform linear fitting: The resulting slope This is the measured tension calibration coefficient for that cross-section. A fitting example is shown below. Figures 20-22 As shown.

[0075] Calculate three cross-sections The arithmetic mean of the values ​​is used to obtain the average measured tension calibration coefficient. Absolute calibration is performed during the on-site tensioning process, combining theoretical relationships with the actual engineering equipment and material properties to ensure the authenticity and engineering applicability of the calibration results.

[0076] Step S4: Determine the calibration relationship during service phase The result obtained in step S2 The result obtained in step S3 Multiplying these values ​​yields the average measured calibration coefficients used for service life monitoring. ,Right now: This step integrates the "conversion relationship" of theoretical simulation with the "absolute calibration" of on-site tensioning, ultimately yielding... It directly characterizes the effective tension value corresponding to the unit micro-strain measured on the working anchor during the service phase, laying the mathematical foundation for long-term monitoring.

[0077] 2. Monitoring Phase Step S5: Service life monitoring and effective prestress calculation During the bridge's operational phase, long-term continuous monitoring will be conducted.

[0078] a. Temperature drift correction: like Figure 9 As shown, a reference anchor of the same type and not subjected to force is set up next to the measured anchor 101, and a temperature compensation strain gauge that corresponds exactly to the measured anchor is attached to it.

[0079] Real-time acquisition and measurement of strain at various cross-sections of the anchor Strain corresponding to the reference anchor .

[0080] Calculate the corrected strain: For each cross-section, calculate the temperature-corrected strain value: The differential method almost completely eliminates the influence of environmental temperature changes and sensor time drift on strain readings, which is a core measure to ensure the accuracy and stability of long-term monitoring data.

[0081] b. Calculate the average corrected strain: for the three cross-sections Take the average value to obtain the current average corrected strain. : .

[0082] c. Calculate the effective prestress: Calculate the current effective tension: .

[0083] Calculate the current effective prestress: .in = = 6 × 140mm², which is the total cross-sectional area of ​​the prestressing tendons.

[0084] Using pre-calibrated coefficients It can directly and quickly convert the strain values ​​measured in real time into the effective prestress values ​​that are of most concern to the project, thus enabling real-time evaluation.

[0085] The monitoring device can automatically perform the above calculations at a set frequency (e.g., per hour) and record and display the curve of effective prestress changing over time (age). Figure 23 , Figure 24 As shown in the figure, it enables true long-term, automatic, and real-time monitoring.

[0086] like Figure 23 , Figure 24 As shown, the effective prestress-time curve obtained by the method of this invention is smooth and continuous, without obvious abnormal jumps, and its trend is consistent with the theoretical loss laws of shrinkage, creep, relaxation, etc. of prestressed concrete structures. During the monitoring period of up to 270 days, the monitoring device continuously and stably output data, fully verifying the reliability, accuracy, and strong environmental adaptability of the method of this invention in long-term monitoring.

[0087] Example 2: Specific Implementation of Monitoring Device like Figure 25 As shown, the monitoring device of the present invention is a hardware and software implementation of the method in Embodiment 1, and includes the following parts: Sensing unit: It includes 12 working strain gauges 102 installed on the three target sections of the measured working anchor, and 12 temperature compensation strain gauges installed at the corresponding positions of the reference anchor.

[0088] Protective structures (such as) Figure 10-13 (As shown): All strain gauges and connecting cables are protected by a layered protective structure. Inner layer (sealing layer 106): room temperature curing silicone, moisture-proof and insulating, blocking electrochemical corrosion.

[0089] Middle layer (buffer layer 107): Closed-cell rubber foam, for stress buffering and heat insulation.

[0090] Outer layer (protective shell 108): segmented polypropylene shell, protected against physical impact, and fixed by a pivot 109 and bolts 110.

[0091] The specific parameters of this layered protective structure (such as silicone hardness of 20-25, thickness of 0.5-2mm, and closed-cell foam density of 80-120kg / m³) are based on a large number of laboratory environmental simulation accelerated aging tests and long-term field exposure tests. It is an optimized balance between ensuring excellent protective performance (moisture-proof, cushioning, and impact resistance) and not affecting the sensor's measurement sensitivity. It is not a conventional or arbitrary choice in this field.

[0092] It should be further explained that the triple protection system provides comprehensive protection for the sensor, ensuring that it can work stably for a long time in harsh outdoor environments such as humid, temperature-different, and easily impacted bridges and tunnels, which is the physical guarantee for achieving reliable monitoring for decades.

[0093] Data acquisition and processing unit 204: An integrated embedded monitoring station is used. Its data processing module pre-stores the conversion coefficients obtained from finite element analysis. And run a dedicated algorithm program.

[0094] During construction tensioning, data is collected and steps S3 and S4 are automatically executed to complete the calibration of the monitoring device.

[0095] During service, the sensor unit continuously collects data and automatically executes step S5 for temperature correction and effective prestress calculation.

[0096] The data acquisition and processing unit 204 integrates the complex calibration and calculation process into the hardware and software, achieving full automation. This greatly reduces the difficulty of manual operation and maintenance costs, and improves the engineering practicality and reliability of the monitoring device.

[0097] Storage unit 205: Used to store all raw data, calibration coefficients and calculation results.

[0098] Input unit 202 and display unit 203: are typically integrated into a touch screen for parameter setting, local real-time data display (such as effective prestress curve) and monitoring device status.

[0099] Power supply unit: A combination of solar panels and batteries can be used to provide continuous and stable power to the monitoring device.

[0100] This monitoring device is highly integrated and operates automatically, realizing a complete closed loop from data acquisition, intelligent processing, result storage to visualization output, providing a stable, reliable and efficient solution for long-term health monitoring of prestressed structures.

[0101] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0102] Furthermore, it should be noted that the scope of the methods and monitoring devices in the embodiments of the present invention is not limited to performing functions in the order shown or discussed. It may also include performing functions substantially simultaneously or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

[0103] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of the present invention.

Claims

1. A method for effective prestress calibration of a high-speed railway continuous beam bridge, characterized in that, Includes the following steps: Calibration phase: S1. Based on the finite element model of the working anchor, obtain the corresponding data of simulated strain and simulated force of multiple preset sections under simulated tensioning and simulated service conditions. S2. Based on the simulation data, establish the first calibration relationship from simulated strain to simulated force for each section, and calculate an average conversion coefficient λ based on the first calibration relationship between the two working conditions. S3. During the actual prestressing tensioning process, measure the actual strain and total tension of each preset section, and establish a second calibration relationship between the actual strain and the total tension of each section. S4. Combining the conversion coefficient λ with the second calibration relationship, determine the third calibration relationship for service life monitoring; Monitoring phase: S5. During the service life of the structure, measure the real-time strain of each of the preset sections, and calculate the current effective prestress value based on the third calibration relationship and the processed real-time strain.

2. The method according to claim 1, characterized in that, In step S2, the method for calculating the conversion coefficient λ is as follows: for each cross section, obtain the first coefficient under the tensioning condition from the first calibration relationship. and the second coefficient under service conditions Calculate the sub-transformation coefficient of this cross-section. The average conversion coefficient is obtained by averaging the sub-conversion coefficients of all cross sections. .

3. The method according to claim 2, characterized in that, The preset cross-sections are three, located at the center of the working anchor axis, near the tensioning end, and near the anchoring end, respectively.

4. The method according to claim 2 or 3, characterized in that, The first calibration relationship and the second calibration relationship are established through linear fitting.

5. The method according to claim 1, characterized in that, In step S5, the processed real-time strain refers to the strain value after temperature drift correction of the measured real-time strain.

6. The method according to claim 5, characterized in that, The temperature drift correction is achieved through the following steps: S51. Set a reference anchor that is made of the same material and in the same environment as the measured working anchor, but is not subjected to any force; S52. Obtain the reference strain of the reference anchor at the same position as the measured working anchor; S53. Subtract the corresponding reference strain from the real-time strain to obtain the strain value after temperature drift correction.

7. The method according to claim 1, characterized in that, The strain of each of the preset cross sections is measured by at least four strain sensors uniformly arranged circumferentially on the cross section, and the average value of the readings of the at least four strain sensors is taken as the strain value of the cross section.

8. An effective prestress monitoring device for a high-speed railway continuous beam bridge, used to implement the method according to any one of claims 1-7, characterized in that, include: The sensing unit is configured on multiple preset sections of the working anchor to collect strain signals; A data processing unit, communicatively connected to the sensing unit, is configured to: Store the average conversion coefficients obtained from finite element analysis. ; During the calibration phase, a second calibration relationship is established based on the data collected by the sensing unit during the tensioning process, and a third calibration relationship is obtained by calculation. During the monitoring phase, the effective prestress value is calculated and output based on the real-time strain data collected by the sensing unit and the third calibration relationship.

9. The monitoring device according to claim 8, characterized in that, The sensing unit also includes a temperature compensation sensor deployed on the reference anchor; the data processing unit is further configured to: use the data from the temperature compensation sensor to perform temperature drift correction on the real-time strain data collected from the working anchor.

10. The monitoring device according to claim 8 or 9, characterized in that, The sensor and circuitry in the sensing unit are externally protected by a layered protective structure, which includes a sealing layer, a buffer layer, and an outer protective shell arranged sequentially from the inside out.

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