Bridge monitoring method and device, electronic equipment and storage medium

Abstract

The invention relates to a bridge monitoring method and device, electronic equipment and a storage medium, and belongs to the technical field of bridge monitoring, and the method comprises the steps: obtaining the detection data of a grating array optical fiber sensor disposed on a bridge; decomposing the detection data based on wavelet transform to obtain low-frequency signal data in the detection data; and determining the strain condition of the bridge based on the low-frequency signal data. And the beneficial effects are briefly described. The strain condition of the bridge is monitored through the grating array optical fiber sensors arranged on the bridge, the strain condition of the bridge structure can be accurately measured, the response is fast, and the real-time performance is high. Moreover, the detection data are decomposed based on wavelet transform, high-frequency noise data in the detection data are filtered, low-frequency signal data in the detection data are reserved, and the strain condition of the bridge is determined based on the low-frequency signal data, so that the data reliability can be ensured while the real-time performance is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of bridge monitoring, and in particular to a bridge monitoring method, device, electronic equipment and storage medium. Background Art

[0002] With the rapid development of transportation networks, the forms of bridge construction are becoming more and more diverse, the spans are getting longer and longer, and the role in national economic production is becoming more and more important. Therefore, bridge safety assessment and health monitoring have received widespread attention. Bridge monitoring mainly obtains the actual working status of the bridge by testing the bearing capacity of the bridge, and determines the safety of the bridge based on the actual working status of the bridge.

[0003] Traditional bridge safety monitoring methods include methods that use distributed fiber optic sensing technology for monitoring. Distributed fiber optic sensing technology mainly uses Raman scattering, Brillouin scattering or Rayleigh scattering to detect strain conditions, but the optical signal of optical fiber scattering is very weak. For example, the optical signal of Raman scattering is about one billionth of the incident light. Such weak optical signals make signal detection and processing very difficult. It is necessary to average the detection data multiple times to improve the measurement accuracy, and the real-time performance is poor and the cost is high. Summary of the invention

[0004] In view of this, it is necessary to provide a bridge monitoring method, device, electronic device and storage medium to solve the problem of poor real-time monitoring using distributed optical fiber sensing technology in the prior art.

[0005] In order to solve the above problems, in a first aspect, the present invention provides a bridge monitoring method, comprising: Acquire detection data of grating array optical fiber sensors deployed on the bridge; Decomposing the detection data based on wavelet transform to obtain low-frequency signal data in the detection data; The strain condition of the bridge is determined based on the low-frequency signal data.

[0006] Optionally, decomposing the detection data based on wavelet transform to obtain low-frequency signal data in the detection data includes: The detection data is decomposed into two layers based on Haar wavelet transform to obtain target low-frequency signal data in the detection data.

[0007] Optionally, the performing a two-layer decomposition on the detection data based on the Haar wavelet transform to obtain target low-frequency signal data in the detection data includes: The detection data is decomposed at the first level by the following formula to obtain the first low-frequency signal data: :

[0008] in, k is the index in the first-level decomposition process, k The value range is 1~n / 2, each k Corresponding to a pair of input data ; The first low-frequency signal data is decomposed by the following formula to obtain the target low-frequency signal data: :

[0009] in, j is the index in the second-level decomposition process, j The value range is 1~n / 4, each j Corresponding to a pair of elements .

[0010] Optionally, the bridge includes a box girder, the box girder includes a web; the web includes a grating array optical fiber sensor arranged along a downward curved parabolic path.

[0011] Optionally, the web also includes a grating array optical fiber sensor arranged along an upward curved parabolic path.

[0012] Optionally, the box girder includes a top plate and a bottom plate; the top plate and the bottom plate include grating array optical fiber sensors arranged along a straight path.

[0013] Optionally, the bridge includes grating array optical fiber sensors arranged in a through-length fold-back manner.

[0014] In a second aspect, the present invention further provides a bridge monitoring device, comprising: A detection data acquisition module, used to acquire detection data of a grating array optical fiber sensor arranged on the bridge; A data denoising module, used for decomposing the detection data based on wavelet transform to obtain low-frequency signal data in the detection data; The strain determination module is used to determine the strain condition of the bridge based on the low-frequency signal data.

[0015] In a third aspect, the present invention further provides an electronic device comprising a memory and a processor, wherein the memory is used to store programs; and the processor is coupled to the memory and is used to execute the programs stored in the memory to implement the steps in any one of the above-mentioned bridge monitoring methods.

[0016] In a fourth aspect, the present invention further provides a computer-readable storage medium for storing a computer-readable program, wherein the program or instruction, when executed by a processor, can implement the steps in any one of the above-mentioned bridge monitoring methods.

[0017] The beneficial effects of the present invention are: On the one hand, the present invention monitors the strain of the bridge through the grating array fiber optic sensor arranged on the bridge, which can realize the accurate measurement of the strain of the bridge structure, and has fast response and strong real-time performance. On the other hand, after obtaining the detection data of the grating array fiber optic sensor, the present invention decomposes the detection data based on wavelet transform, filters the high-frequency noise data in the detection data, and the high-frequency noise data represents the strain caused by the temperature load, and retains the low-frequency signal data in the detection data, and the low-frequency signal data represents the live load such as traffic load and wind load; the strain of the bridge is determined based on the live load, which can ensure the reliability of the data while ensuring real-time performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of a flow chart of an embodiment of a bridge monitoring method provided by the present invention; Figure 2 A schematic diagram of an embodiment of a bridge monitoring method provided by the present invention; Figure 3 A schematic diagram of data noise reduction processing provided by the present invention; Figure 4 A schematic diagram of various wavelet transform processing results provided by the present invention; Figure 5 A schematic diagram of the processing result of the Haar wavelet transform provided by the present invention; Figure 6 A schematic diagram of a linear arrangement scheme of grating array sensors provided by the present invention; Figure 7 A schematic diagram of a curved layout scheme of a grating array sensor provided by the present invention; Figure 8 A schematic diagram of another linear arrangement scheme of grating array sensors provided by the present invention; Fig. 9 A schematic structural diagram of an embodiment of a bridge monitoring device provided by the present invention. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0020] In the description of the embodiments of the present invention, unless otherwise specified, "multiple" means two or more. "First", "second", etc. involved in the embodiments of the present invention are used to distinguish similar objects, and are not used to describe a specific order or sequence, nor are they used to indicate or imply their relative importance or implicitly indicate the number of indicated technical features. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more.

[0021] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0022] Reference Figure 1 , shows a flow chart of an embodiment of the bridge monitoring method provided by the present invention, including: S101, acquiring detection data of a grating array optical fiber sensor arranged on a bridge.

[0023] S102, decomposing the detection data based on wavelet transform to obtain low-frequency signal data in the detection data.

[0024] S103: Determine the strain condition of the bridge based on the low-frequency signal data.

[0025] The bridge can be a hollow slab bridge, which is a bridge with a hollow structure inside the beam to reduce the deadweight and increase the bearing capacity of the structure. Hollow slab bridges are widely used in highway bridges, especially bridges with small and medium spans. Hollow slab bridges are also a common choice in some small pedestrian bridges, bicycle bridges and flyovers.

[0026] As a new type of fiber optic sensor, the basic principle of grating array fiber optic sensor is that when the element is subjected to external strain, temperature, pressure, etc., the central wavelength of its emission spectrum will shift, and the change of the measured value will be detected by the slight change of the central wavelength. The grating array distributed sensor uses a small amount of optical fiber scientifically laid on the bridge, which can meet the cost and accuracy requirements of bridge monitoring.

[0027] The low-frequency component in the bridge strain data is caused by the temperature load, and the high-frequency component is caused by the live load (traffic load and wind load). Because of the coupling of these components, the bridge strain monitoring data has multi-component characteristics, which makes it difficult to evaluate the service status of the bridge structure based on live load. Therefore, this embodiment decomposes the detection data based on wavelet transform to obtain low-frequency signal data in the detection data, and determines the strain change of the bridge caused by the change of live load based on the low-frequency signal data.

[0028] On the one hand, the present invention monitors the strain of the bridge through the grating array fiber optic sensor arranged on the bridge, which can realize the accurate measurement of the strain of the bridge structure, and has fast response and strong real-time performance. On the other hand, after obtaining the detection data of the grating array fiber optic sensor, the present invention decomposes the detection data based on wavelet transform, filters the high-frequency noise data in the detection data, and the high-frequency noise data represents the strain caused by the temperature load, and retains the low-frequency signal data in the detection data, and the low-frequency signal data represents the live load such as traffic load and wind load; the strain of the bridge is determined based on the live load, which can ensure the reliability of the data while ensuring real-time performance.

[0029] Reference Figure 2 , showing a schematic diagram of an embodiment of the bridge monitoring method provided by the present invention. A grating array optical fiber sensor is arranged on the bridge, and the data detected by the grating array optical fiber sensor is transmitted to a lower computer, and the lower computer then transmits the detection data to a host computer, so that the host computer performs further processing such as noise reduction on the detection data. The host computer decomposes the detection data based on wavelet transform to obtain high-frequency signal data and low-frequency signal data, the high-frequency signal data is the strain data caused by temperature load, and the low-frequency signal data is the strain data caused by traffic load and wind load.

[0030] In one embodiment, S102 may specifically include: performing a two-layer decomposition on the detection data based on Haar wavelet transform to obtain target low-frequency signal data in the detection data.

[0031] Haar wavelet transform is the simplest wavelet transform method, proposed by Alfred Haar in 1909. It is a discrete wavelet transform suitable for time-frequency analysis and data compression of signals. Haar wavelet transform decomposes the signal into components of different scales, thereby analyzing it simultaneously in the time domain and frequency domain. The core of Haar wavelet transform is Haar wavelet basis function, which is one of the simplest wavelet basis functions.

[0032] To ensure timeliness, this embodiment uses Haar wavelet transform with high computational efficiency to decompose the detection data, and only performs two-layer decomposition.

[0033] In one embodiment, the step of performing two-layer decomposition on the detection data based on the Haar wavelet transform to obtain the target low-frequency signal data in the detection data may specifically include: The first layer of detection data is decomposed by the following formula to obtain the first low-frequency signal data: and the first high frequency signal data :

[0034]

[0035] in, k is the index in the first-level decomposition process, k The value range is , each k Corresponding to a pair of input data ; The first low-frequency signal data and the first high-frequency signal data are decomposed by the following formula to obtain the target low-frequency signal data: and target high frequency signal data :

[0036]

[0037] in, j is the index in the second-level decomposition process, j The value range is , each j Corresponding to a pair of elements .

[0038] Calculation results It is an approximation of the low-frequency component of the original detection data after 2-layer decomposition, representing the low-frequency part of the detection data. In this embodiment, it is retained as the result of signal processing and reflects the overall trend of the signal data. , Represents the high-frequency part in the detection data, which is removed as noise in this embodiment.

[0039] Reference Figure 3 , showing a data denoising processing schematic diagram provided by the present invention. On the host computer, the detection data and the type of wavelet transform for processing the detection data can be selected, and the types of wavelet transform include haar, db4, sym4, coif1 and the like. And the number of decomposition layers of the wavelet transform can also be selected. After the selection, the host computer displays the detection data denoising processing result.

[0040] Reference Figure 4, shows a schematic diagram of the processing results of various wavelet transforms provided by the present invention. In the figure, from top to bottom, the same detection data is subjected to haar, db4, sym4, and coif1 wavelet transform processing, and the number of decomposition layers is 1, and the noise reduction processing results of the detection data are obtained. The processing results are similar, but the haar wavelet transform processing is faster.

[0041] Reference Figure 5 , shows a schematic diagram of the processing result of the haar wavelet transform provided by the present invention. In the figure, the detection data denoising processing result is obtained when the detection data is processed by the haar wavelet transform and the decomposition layer number is 2 layers.

[0042] In one embodiment, the bridge includes a box girder, the box girder includes a web; the web includes a grating array optical fiber sensor arranged along a downward curved parabolic path.

[0043] A bridge consists of a beam and supports. The beam is the main load-bearing structure of the bridge, usually made of reinforced concrete or prestressed concrete. The beam can be in different forms such as solid beam, T-beam, box beam, etc.

[0044] A box girder is a closed box section consisting of top and bottom flanges (top and bottom plates) and webs on both sides.

[0045] The web is located on both sides of the box girder, connecting the top and bottom flanges to form the sides of the box girder. The web mainly bears the shear force in the beam. Shear force is the lateral force generated by the beam under load, and the web resists this force through its high shear strength. The web also participates in bearing the torque in the beam. Torque is the torsional force generated by the beam under eccentric load, and the web resists this force through its torsion resistance.

[0046] The grating array fiber optic sensor is arranged on the web according to a large radius curve, or a parabolic path. Its arrangement is roughly perpendicular to the actual cracking direction of the beam, thereby increasing the density of the grating detection points, monitoring the stress distribution characteristics of the web bending-shear coupling stress area, increasing the dimension of the perception data matrix, and approximately achieving the real-time monitoring effect of the principal stress of the surface area.

[0047] In one embodiment, the web further includes a grating array optical fiber sensor arranged along an upward curved parabolic path.

[0048] In this embodiment, the grating array optical fiber sensor arranged in an upward curved parabolic path on the web can provide additional monitoring of the bridge support and the mid-span center axis position.

[0049] The mid-span axis of a bridge refers to the geometric centerline of the bridge in the span direction. For a simply supported beam bridge, this line is usually located at the midpoint between the two end supports; for a continuous beam bridge or a multi-span bridge, this line is located at the center of each span.

[0050] The support is the connection between the beam and the pier or abutment. The function of the support is to transfer the load of the beam to the pier or abutment and allow the beam to have a certain displacement under temperature changes and loads.

[0051] In one embodiment, the box beam includes a top plate and a bottom plate; the top plate and the bottom plate include grating array optical fiber sensors arranged along a straight path.

[0052] In one embodiment, the bridge includes grating array optical fiber sensors arranged in a through-length fold-back manner.

[0053] The full-length foldback method is to lay out the grating array fiber optic sensor along the length direction and fold it back at certain positions to form a closed loop. This method can achieve continuous monitoring of the entire length of the structure.

[0054] The present invention combines the structural characteristics of the hollow slab bridge and uses a full-coverage optical fiber cross-layout scheme to deploy grating array optical fiber sensors on the hollow slab bridge to monitor the strain data of the hollow slab bridge, thereby meeting the dual requirements of cost-effectiveness and timeliness in the monitoring of the hollow slab bridge, realizing real-time monitoring of the health status of the bridge, timely discovering and handling possible structural problems, and greatly improving the safety and economy of bridge maintenance.

[0055] The present invention uses grating array fiber optic sensors to monitor bridges, and can perform accurate strain measurement on the entire bridge structure. Combined with a targeted monitoring system, it ensures the response speed and accuracy when dealing with sudden stress changes, while optimizing the filtering ability of high-frequency noise signals, ensuring the efficiency and reliability of the signal processing process.

[0056] The present invention adopts a box beam with a standard span of 25m, sets a support 0.4m away from the beam end, and conducts experiments on three layout schemes. Strain gauges are attached to the web on the north side of the box beam body to compare with the detection results of the grating array fiber optic sensor.

[0057] Reference Figure 6, which is a schematic diagram of the linear layout scheme of the grating array sensor provided by the present invention. The web of the box girder adopts a full-length linear layout, the purpose of which is to monitor the strain field of the structure under concentrated load and near the bending-shear crack area in real time, and to grasp the stress redistribution law before and after the cracking of the complex stress area. The fiber grating sensors at the top and bottom of the box girder adopt a linear full-length return layout scheme, the purpose of which is to observe the positive stress distribution at the top and bottom of the beam in real time, and together with the strain data monitored by the web, form the global distribution strain field of the full-scale box girder, and systematically grasp the structural force characteristics. The total layout length of the grating array optical fiber is distributed as follows: ① Top plate: 147.6m fiber grating. ② Web: 123.0m fiber grating. ③ Bottom plate: 98.4m fiber grating. A 10% length redundancy is set to meet the minimum anchoring length and turning radius requirements of the new generation of fiber array sensing optical fibers. Therefore, the total length of the fully distributed fiber Bragg grating required is 1.1×(147.6+123.0+98.4)≈406.0m.

[0058] Reference Figure 7 , which is a schematic diagram of a curved layout scheme of a grating array sensor provided by the present invention. A grating array optical fiber with a large radius curve is laid out at the web of the beam, that is, a downward-bent grating array optical fiber is laid out, and the layout should be roughly perpendicular to the actual cracking direction of the above-mentioned beam, wherein the web of the box beam is laid out in an oblique broken line, and the curve is arranged in a parabola, the top of the parabola is near the central axis of the mid-span of the bridge and close to the bottom of the beam, and the two ends of the parabola are near the intersection of the bridge and the support and close to the top of the beam; the fiber grating sensors at the top and bottom of the box beam are laid out in a straight-line full-length return type. The optical fibers on the web side are all attached to the south side of the beam. In summary, the total layout length distribution is: ① Top plate: 147.60m fiber grating. ② Web: 98.42m fiber grating. ③ Bottom plate: 98.40m fiber grating. A 10% length redundancy is set to meet the minimum anchoring length and turning radius requirements of the new generation of fiber array sensing optical fibers. Therefore, the total length of the fully distributed fiber Bragg grating required is 1.10×(147.60+98.42+98.40)≈378m.

[0059] Reference Figure 8, which is a schematic diagram of another straight-line arrangement scheme of grating array sensors provided by the present invention. A new grating array optical fiber with a large radius curve is arranged at the web of the beam body, and the arrangement is roughly perpendicular to the actual cracking direction of the beam body. In order to increase the density of the grating array sensing optical fiber sensor, monitor the stress distribution characteristics of the web bending-shear coupling stress area, increase the dimension of the sensing data matrix, and approximately achieve the real-time monitoring effect of the principal stress of the surface area, on the basis of the above scheme, two upward bending optical fibers are additionally arranged to supplement the strain monitoring data of the bottom area near the support and the area above the neutral axis in the mid-span. The curve is arranged in a parabola, the top of the parabola is near the mid-span center axis of the bridge, and the bottom of the parabola is near the intersection of the bridge and the support. The fiber grating sensors at the top and bottom of the box beam are arranged in a full-length foldback style. The optical fibers on the web side are all attached to the south side of the beam body. In summary, the total arrangement length is distributed as follows: ① Top plate: 147.60m fiber grating. ② Web: 138.46m fiber grating. ③ Bottom plate: 98.40m fiber grating. A 10% length redundancy is set to meet the minimum anchoring length and turning radius requirements of the new generation of fiber array sensing fibers. Therefore, the total length of the required full-filled fiber Bragg grating is 1.10×(147.60+138.46+99.40)≈424.00m.

[0060] Through experimental analysis, Figure 6 and Figure 7 Compared with the layout method, Figure 6 The layout is convenient and the operation is simple; however, the layout rules do not conform to the cracking law of the web, and the collected results are smaller than the actual results. Figure 7 The layout will be more complicated, but the amount of sensing optical fiber used is less, the layout direction is consistent with the distribution law of principal stress, and the collection results are more accurate.

[0061] Figure 7 and Figure 8 Compared with the layout method, Figure 7 The layout of the support cannot monitor the strain field distribution in the bottom area near the support and the area above the neutral axis in the span. Figure 8 The layout ensures monitoring accuracy while covering a wide monitoring area.

[0062] Reference Fig. 9 , shows a schematic structural diagram of an embodiment of a bridge monitoring device provided by the present invention, the device 900 comprises: The detection data acquisition module 901 is used to acquire the detection data of the grating array optical fiber sensor arranged on the bridge; A decomposition module 902 is used to decompose the detection data based on wavelet transform to obtain low-frequency signal data in the detection data; The strain determination module 903 is used to determine the strain condition of the bridge based on the low-frequency signal data.

[0063] It should be noted that the implementation principle or implementation process of the above modules can refer to the embodiment of the above bridge monitoring method, and will not be described one by one here.

[0064] In one embodiment, the present invention further provides an electronic device, including a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the steps of any one of the above-mentioned bridge monitoring methods are implemented.

[0065] In one embodiment, the present invention further provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by the processor, the steps of any one of the above-mentioned bridge monitoring methods are implemented.

[0066] Those skilled in the art will appreciate that all or part of the processes of the above-mentioned embodiments can be implemented by instructing related hardware through a computer program, and the program can be stored in a computer-readable storage medium, wherein the computer-readable storage medium is a disk, an optical disk, a read-only storage memory, or a random access memory, etc.

[0067] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A bridge monitoring method, characterized in that: include; Acquire detection data of grating array optical fiber sensors deployed on the bridge; Decomposing the detection data based on wavelet transform to obtain low-frequency signal data in the detection data; The strain condition of the bridge is determined based on the low-frequency signal data.

2. The bridge monitoring method according to claim 1, characterized in that: Decomposing the detection data based on wavelet transform to obtain low-frequency signal data in the detection data includes: The detection data is decomposed into two layers based on Haar wavelet transform to obtain target low-frequency signal data in the detection data.

3. The bridge monitoring method according to claim 2, characterized in that: The method of performing a two-layer decomposition on the detection data based on the Haar wavelet transform to obtain target low-frequency signal data in the detection data includes: The detection data is decomposed at the first level by the following formula to obtain the first low-frequency signal data: : in, k is the index in the first-level decomposition process, k The value range is 1~n / 2, each k Corresponding to a pair of input data ; The first low-frequency signal data is decomposed by the following formula to obtain the target low-frequency signal data: : in, j is the index in the second-level decomposition process, j The value range is 1~n / 4, each j Corresponding to a pair of elements .

4. The bridge monitoring method according to claim 1, characterized in that: The bridge comprises a box girder, and the box girder comprises a web; the web comprises a grating array optical fiber sensor arranged along a downward curved parabolic path.

5. The bridge monitoring method according to claim 4, characterized in that: The web also includes a grating array optical fiber sensor arranged along an upward curved parabolic path.

6. The bridge monitoring method according to claim 5, characterized in that: The box beam comprises a top plate and a bottom plate; the top plate and the bottom plate comprise grating array optical fiber sensors arranged along a straight path.

7. The bridge monitoring method according to claim 1, characterized in that: The bridge includes grating array optical fiber sensors arranged in a through-length folding manner.

8. A bridge monitoring device, characterized in that: include: A detection data acquisition module, used to acquire detection data of a grating array optical fiber sensor arranged on the bridge; A data denoising module, used for decomposing the detection data based on wavelet transform to obtain low-frequency signal data in the detection data; The strain determination module is used to determine the strain condition of the bridge based on the low-frequency signal data.

9. An electronic device, characterized in that: comprising a memory and a processor, wherein: The memory is used to store programs; The processor is coupled to the memory and is used to execute the program stored in the memory to implement the steps of the bridge monitoring method described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: Used to store a computer-readable program, wherein when the program or instruction is executed by a processor, the steps of the bridge monitoring method described in any one of claims 1 to 7 can be implemented.

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