A steel bridge deck panel deterioration detection system and method based on grating array sensing

Abstract

The application discloses a steel bridge deck panel deterioration detection system and method based on a grating array sensor. The steel bridge deck panel deterioration detection system based on the grating array sensor comprises a strain sensing network, a demodulator and a data processing unit. The strain sensing network comprises a first optical cable group, a second optical cable group, a third optical cable group and a fourth optical cable group arranged along the length direction of the orthotropic steel bridge deck panel. The first optical cable group is arranged on the heavy lane on the upstream side. The second optical cable group is arranged between the heavy lane and the small lane on the upstream side. The third optical cable group is arranged on the heavy lane on the downstream side. The fourth optical cable group is arranged between the heavy lane and the small lane on the downstream side. The demodulator is optically connected with the first optical cable group, the second optical cable group, the third optical cable group and the fourth optical cable group respectively. The data processing unit is connected with the demodulator and is used for receiving, storing, displaying and analyzing each strain monitoring data. The application can solve the problem that it is difficult to effectively judge the damage starting position and the evolution process.

Description

Technical Field

[0001] This invention relates to the field of bridge health monitoring technology, specifically to a steel bridge deck deterioration detection system and method based on grating array sensing. Background Technology

[0002] Orthotropic steel bridge decks have many advantages, such as light weight, high structural stiffness, high load-bearing capacity, fast construction speed, and wide applicability. They have been widely used in the construction of modern long-span suspension bridges, cable-stayed bridges, and beam bridges.

[0003] Orthotropic steel bridge decks are important load-bearing components of long-span steel bridges, typically composed of a top plate, bottom plate, U-ribs, diaphragms, and related welded structures. Under long-term repeated vehicle loads, the stress around the weld seams connecting the U-ribs to the top or bottom plate, and the area near the weld holes of the diaphragms, are complex and prone to becoming sensitive areas for fatigue crack initiation and propagation. Therefore, effective monitoring and evaluation of these fatigue-sensitive areas are of great significance for ensuring the structural safety and service durability of steel bridge decks.

[0004] However, while resistance strain gauges or conventional fiber optic grating sensors can avoid the error problems caused by relying on human experience, they can only obtain the strain response at discrete measurement points and are difficult to reflect the continuous strain distribution characteristics of fatigue-sensitive structures along the longitudinal direction of the bridge. Therefore, it is difficult to effectively determine the damage initiation location and its evolution process. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned technical deficiencies and propose a steel bridge deck deterioration detection system and method based on grating array sensing. This solves the technical problem that the existing technology can only obtain the strain response at discrete measuring points and is difficult to reflect the continuous strain distribution characteristics of fatigue-sensitive structures along the longitudinal direction of the bridge, making it difficult to effectively determine the damage initiation location and its evolution process.

[0006] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a steel bridge deck degradation detection system based on a grating array sensor, configured to be connected to an orthotropic steel bridge deck, the orthotropic steel bridge deck having an upstream side and a downstream side arranged symmetrically, the upstream side and the downstream side respectively including a heavy lane and a light lane, comprising: The strain sensing network includes a first optical cable group, a second optical cable group, a third optical cable group, and a fourth optical cable group arranged along the length direction of the orthotropic steel bridge deck. The first optical cable group is laid on the heavy-duty lane on the upstream side, the second optical cable group is laid between the heavy-duty lane and the small lane on the upstream side, the third optical cable group is laid on the heavy-duty lane on the downstream side, and the fourth optical cable group is laid between the heavy-duty lane and the small lane on the downstream side. The demodulator is optically connected to the first, second, third, and fourth optical fiber groups respectively, and is used to collect and convert the changes in each reflectance spectrum in real time; and The data processing unit, connected to the demodulator, is used to receive, store, display, and analyze various strain monitoring data.

[0007] In some embodiments, the orthotropic steel bridge deck includes a top plate, a bottom plate, U-ribs, diaphragms, and weld holes. The bottom plate and the top plate are spaced apart from each other, and a plurality of U-ribs are uniformly arranged on the surface of the top plate or the bottom plate. The diaphragms are spaced apart along the longitudinal direction of the orthotropic steel bridge deck, and the diaphragms are provided with weld holes for the passage of sensing optical cables. The first optical cable group includes two first optical cables, which are parallel to each other and spaced apart. They are evenly distributed in the area near the weld seam where the U-ribs corresponding to the heavy vehicle track lines in the upstream lane connect to the top plate, for obtaining the strain response of the upstream heavy vehicle track area.

[0008] In some embodiments, the second optical cable group includes two second optical cables. One second optical cable is laid in the area near the weld seam of the U-rib connecting the top plate at the junction of the upstream heavy lane and the light lane. The other second optical cable is located below the projection of the first second optical cable and is laid in the area near the weld seam of the U-rib connecting the bottom plate at the junction of the upstream heavy lane and the light lane.

[0009] In some embodiments, the third optical cable group includes two third optical cables, which are parallel to each other and spaced apart, and are evenly distributed in the area near the weld seam where the U-rib and the top plate are connected, corresponding to the heavy vehicle track line in the downstream side lane, to obtain the strain response of the heavy vehicle track area in the downstream side.

[0010] In some embodiments, the fourth optical cable group includes two fourth optical cables. One fourth optical cable is laid in the area near the weld seam of the U-rib connecting the top plate at the junction of the downstream heavy lane and the light lane. The other fourth optical cable is located below the projection of the first fourth optical cable and is laid in the area near the weld seam of the U-rib connecting the bottom plate at the junction of the downstream heavy lane and the light lane.

[0011] In some embodiments, the first optical cable, the second optical cable, the third optical cable and the fourth optical cable pass through the welding holes on the diaphragm in sequence to form an eight-line three-dimensional strain monitoring network that can cover the heavy vehicle wheel track area, the lane intersection reference area and the corresponding area of ​​the bottom plate.

[0012] In some embodiments, the demodulator is optically connected to the first, second, third, and fourth optical cables, and is used to collect the reflection spectrum changes of the grating sensing units in the first, second, third, and fourth optical cables in real time, and convert them into strain monitoring data.

[0013] In some embodiments, the data processing unit can synchronize, register, and segment the strain data of the first, second, third, and fourth optical cables in time, and establish a multi-line collaborative benchmark based on historical monitoring data of the bridge's health stage.

[0014] In some embodiments, the steel bridge deck deterioration detection system based on grating array sensing further includes multiple connecting components. Each connecting component includes a structural adhesive layer and a covering reinforcement layer. The covering reinforcement layer is connected to the top plate, bottom plate, or U-rib via the structural adhesive layer. The covering reinforcement layer and the top plate, bottom plate, or U-rib together form a receiving cavity for accommodating the first optical cable, the second optical cable, the third optical cable, and the fourth optical cable. The structural adhesive layer is connected to the first optical cable, the second optical cable, the third optical cable, and the fourth optical cable.

[0015] Secondly, the present invention also provides a method for detecting the deterioration of steel bridge decks based on grating array sensing, using the steel bridge deck deterioration detection system based on grating array sensing as described above, with the following specific steps: According to the bridge structure, the first optical cable, the second optical cable, the third optical cable and the fourth optical cable are laid in sequence; The first, second, third, and fourth optical cables are connected to the demodulator via fiber optic patch cords, and the demodulator is connected to the data processing unit. The demodulator performs real-time synchronous monitoring of each grating sensing unit in each sensing optical cable, records the changes in its reflection spectrum, and converts it into strain monitoring data on each measuring line. The data processing unit receives monitoring data from the demodulator in real time and stores, displays and analyzes the data according to the type of survey line and spatial location, thereby obtaining the strain response information of the upstream heavy vehicle trajectory line, the upstream lane intersection reference line, the upstream bottom plate corresponding line, the downstream heavy vehicle trajectory line, the downstream lane intersection reference line and the downstream bottom plate corresponding line along the longitudinal direction of the bridge. Distributed strain data of the heavy vehicle wheel track area, lane boundary reference area and corresponding area of ​​the bottom plate of the orthotropic steel bridge deck were acquired simultaneously, providing basic data support for subsequent establishment of health benchmark model, extraction of multi-line difference characteristics, identification of abnormal sections and carrying out spatiotemporal characterization of deterioration.

[0016] Compared with existing technologies, the beneficial effects of the steel bridge deck deterioration detection system and method based on grating array sensing provided by this invention include: Compared with existing technologies, the first, second, third, and fourth optical cable groups set along the length direction of the orthotropic steel bridge deck can acquire and convert various reflection spectrum changes in real time through a demodulator, and receive, store, display, and analyze various strain monitoring data through a data processing unit. Since each sensing optical cable is laid along the entire length of the preset measurement line, and the positional relationship of each grating sensing unit is known, the system can detect that after the above-mentioned multi-measurement line collaborative index deviates continuously in a specific section, it can combine the amplitude, spatial location, and duration of the abnormal change to map the abnormal section to the corresponding U-rib, connecting weld, or transverse diaphragm area in the bridge structure model. This provides a basis for identifying internal stiffness changes, fatigue damage risks, or abnormal structural evolution trends. It can solve the technical problem in existing technologies that can only obtain strain responses at discrete measurement points and are difficult to reflect the continuous strain distribution characteristics of fatigue-sensitive structures along the longitudinal direction of the bridge, making it difficult to effectively determine the damage initiation location and its evolution process. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a steel bridge deck deterioration detection system based on grating array sensing provided in an embodiment of the present invention; Figure 2 This is a schematic diagram from another perspective of a steel bridge deck deterioration detection system based on grating array sensing provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the connection between the third optical cable group, the connecting component, and the orthotropic steel bridge deck according to an embodiment of the present invention; Figure 4 This is a flowchart of the spatiotemporal characterization data processing for the degradation of orthotropic steel bridge decks provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of a multi-line collaborative reference mode under healthy conditions provided in an embodiment of the present invention; Figure 6 This is a schematic diagram of an abnormal deviation mode of multi-line relationship under the deterioration risk state provided by an embodiment of the present invention.

[0018] Explanation of reference numerals in the attached figures: Orthotropic steel bridge deck 100; top plate 110; bottom plate 120; U-rib 130; diaphragm 140; weld hole 150; strain sensor network 200; first optical cable group 210; first upstream heavy vehicle trajectory optical cable 210a; second upstream heavy vehicle trajectory optical cable 210b; second optical cable group 220; upstream top plate boundary reference optical cable 220a; upstream bottom plate corresponding optical cable 220b; third optical cable group 230; first downstream heavy vehicle trajectory optical cable 230a; second downstream heavy vehicle trajectory optical cable 230b; fourth optical cable group 240; downstream top plate boundary reference optical cable 240a; downstream bottom plate corresponding optical cable 240b; demodulator 300; data processing unit 400; connecting assembly 500; structural adhesive layer 510; covering reinforcement layer 520. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0020] To address the technical problem that existing technologies can only acquire strain responses at discrete measurement points and cannot reflect the continuous strain distribution characteristics of fatigue-sensitive structures along the longitudinal direction of the bridge, thus making it difficult to effectively determine the damage initiation location and its evolution process, this invention provides a steel bridge deck deterioration detection system and method based on grating array sensing. By deploying each sensing optical cable along a preset measurement line and knowing the positional relationship of each grating sensing unit, the system can detect a continuous deviation of the aforementioned multi-measurement line collaborative index in a specific section. By combining the amplitude, spatial location, and duration of the abnormal change, the abnormal section can be mapped to the corresponding U-rib 130, connecting weld, or diaphragm 140 area in the bridge structural model. This provides a basis for identifying internal stiffness changes, fatigue damage risks, or abnormal structural evolution trends.

[0021] Please see Figure 1 , Figure 2This is a schematic diagram of a steel bridge deck degradation detection system and method based on grating array sensing according to an embodiment of the present invention. The steel bridge deck degradation detection system based on grating array sensing is configured to be connected to an orthotropic steel bridge deck 100. The orthotropic steel bridge deck 100 has an upstream side and a downstream side arranged symmetrically, and the upstream side and the downstream side respectively include a heavy lane and a light lane. It includes: a strain sensing network 200, a demodulator 300 and a data processing unit 400. The strain sensing network 200 includes a first optical cable group 210, a second optical cable group 220 and a third optical cable group arranged along the length direction of the orthotropic steel bridge deck 100. Optical cable group 230 and fourth optical cable group 240 are configured. The first optical cable group 210 is laid on the upstream heavy-duty lane, the second optical cable group 220 is laid between the upstream heavy-duty lane and the small lane, the third optical cable group 230 is laid on the downstream heavy-duty lane, and the fourth optical cable group 240 is laid between the downstream heavy-duty lane and the small lane. The demodulator 300 is optically connected to the first optical cable group 210, the second optical cable group 220, the third optical cable group 230, and the fourth optical cable group 240 respectively, and is used to collect and convert various reflection spectrum changes in real time. The data processing unit 400 is connected to the demodulator 300 and is used to receive, store, display, and analyze various strain monitoring data.

[0022] In this device, compared with the prior art, the first optical cable group 210, the second optical cable group 220, the third optical cable group 230 and the fourth optical cable group 240 arranged along the length of the orthotropic steel bridge deck 100 can collect and convert the changes in various reflection spectra in real time through the demodulator 300, and receive, store, display and analyze various strain monitoring data through the data processing unit 400. Since each sensing optical cable is laid out along the preset measurement line and the positional relationship of each grating sensing unit is known, after the system detects that the above-mentioned multi-measurement line coordinated index has continuously deviated in a specific section, it can combine the amplitude, spatial location and duration of the abnormal change to correspond the abnormal section to the area near the corresponding U rib 130, connecting weld or transverse diaphragm 140 in the bridge structure model. This provides a basis for identifying internal stiffness changes, fatigue damage risks or structural abnormal evolution trends. It can solve the technical problem in the prior art that can only obtain the strain response at discrete measurement points and is difficult to reflect the continuous strain distribution characteristics of fatigue-sensitive structures along the longitudinal direction of the bridge, which makes it difficult to effectively judge the damage initiation location and its evolution process.

[0023] In this embodiment, as Figure 1As shown, the orthotropic steel bridge deck 100 includes a top plate 110, a bottom plate 120, U-ribs 130, diaphragms 140, and welding holes 150. The bottom plate 120 and the top plate 110 are spaced apart from each other, and a plurality of U-ribs 130 are evenly arranged on the surface of the top plate 110 or the bottom plate 120. The diaphragms 140 are spaced apart along the longitudinal direction of the orthotropic steel bridge deck 100, and welding holes 150 are provided on the diaphragms 140 for the passage of sensing optical cables.

[0024] The main body of the orthotropic steel bridge deck 100 structure in this application includes a top plate 110, a bottom plate 120, U-ribs 130, diaphragms 140, and weld holes 150.

[0025] Furthermore, the top plate 110 and the bottom plate 120 constitute the main load-bearing plates of the steel box girder, and the U-ribs 130 are arranged along the longitudinal direction of the bridge at corresponding positions of the top plate 110 and the bottom plate 120 to form the longitudinal stiffening structure of the orthotropic steel bridge deck 100.

[0026] Furthermore, the U-rib 130 is connected to the top plate 110 or the bottom plate 120 by a longitudinal connecting weld. The connecting weld and its surrounding area near the weld are fatigue-sensitive areas under repeated vehicle loads, and are also the main deployment area of ​​the sensing optical cable in this embodiment.

[0027] Furthermore, the diaphragm 140 is spaced along the longitudinal direction of the bridge and has welding holes 150 for the passage of sensing optical cables.

[0028] In one embodiment, such as Figure 1 , Figure 2 As shown, the first optical cable group 210 includes two first optical cables, which are parallel to each other and spaced apart. They are evenly distributed in the area near the weld seam where the U-rib 130 and the top plate 110 connect to the heavy vehicle track line in the upstream lane, and are used to obtain the strain response of the heavy vehicle track area in the upstream lane.

[0029] The two first optical cables are respectively the first upstream heavy vehicle track optical cable 210a and the second upstream heavy vehicle track optical cable 210b. They are respectively laid in the area near the weld seam of the U rib 130 and the top plate 110 corresponding to the two heavy vehicle track lines in the upstream side heavy vehicle lane, and are used to obtain the strain response of the upstream heavy vehicle track area.

[0030] In one embodiment, such as Figure 1 , Figure 2As shown, the second optical cable group 220 includes two second optical cables. One second optical cable is laid in the area near the weld seam where the U-rib 130 and the top plate 110 connect at the junction of the upstream heavy lane and the light lane. The other second optical cable is located below the projection of the first second optical cable and is laid in the area near the weld seam where the U-rib 130 and the bottom plate 120 connect at the junction of the upstream heavy lane and the light lane.

[0031] The two second optical cables serve as the upstream top plate junction reference optical cable 220a and the upstream bottom plate corresponding optical cable 220b, respectively.

[0032] Among them, the upstream top plate junction reference optical cable 220a is laid in the area near the weld seam of the connection between the U rib 130 and the top plate 110 at the junction of the upstream side lane and the side lane; the upstream bottom plate corresponding optical cable 220b is laid in the area near the weld seam of the connection between the U rib 130 and the bottom plate 120 corresponding to the transverse projection of the bottom plate 120 and the upstream top plate junction reference optical cable 220a.

[0033] In one embodiment, such as Figure 1 , Figure 2 As shown, the third optical cable group 230 includes two third optical cables, which are parallel to each other and spaced apart. They are evenly distributed in the area near the weld seam where the U-rib 130 and the top plate 110 connect to the heavy vehicle track line in the downstream side lane, and are used to obtain the strain response of the heavy vehicle track area in the downstream side.

[0034] The two third optical cables serve as the first downstream heavy vehicle track optical cable 230a and the second downstream heavy vehicle track optical cable 230b, respectively. They are respectively deployed in the area near the weld seam of the U-rib 130 and the top plate 110 corresponding to the two heavy vehicle track lines in the downstream side heavy vehicle lane, and are used to obtain the strain response of the downstream side heavy vehicle track area.

[0035] In one embodiment, such as Figure 1 , Figure 2 As shown, the fourth optical cable group 240 includes two fourth optical cables. One fourth optical cable is laid in the area near the weld seam where the U-rib 130 and the top plate 110 connect at the intersection of the downstream heavy lane and the light lane. The other fourth optical cable is located below the projection of the first fourth optical cable and is laid in the area near the weld seam where the U-rib 130 and the bottom plate 120 connect at the intersection of the downstream heavy lane and the light lane.

[0036] The two fourth optical cables serve as the downstream roof junction reference optical cable 240a and the downstream floor corresponding optical cable 240b, respectively. Specifically, the downstream roof junction reference optical cable 240a is deployed near the weld area around the connection weld between the U-rib 130 and the roof 110 at the junction of the downstream side lane and the side lane; the downstream floor corresponding optical cable 240b is deployed near the weld area around the connection weld between the U-rib 130 and the floor 120, corresponding to the lateral projection of the floor 120 and the downstream roof junction reference optical cable 240a.

[0037] In one embodiment, the first, second, third, and fourth optical cables pass sequentially through the weld holes 150 on the transverse partition 140 to form an eight-line three-dimensional strain monitoring network capable of covering the heavy vehicle wheel track area, the lane boundary reference area, and the corresponding area of ​​the base plate 120.

[0038] Each sensing optical cable is continuously laid along the longitudinal direction of the bridge and passes through the welding holes 150 on multiple transverse diaphragms 140 in sequence, thereby forming an eight-line three-dimensional strain monitoring network covering the heavy vehicle wheel track area, the lane intersection reference area and the corresponding area of ​​the bottom plate 120.

[0039] In one embodiment, the demodulator 300 is optically connected to the first, second, third, and fourth optical cables to collect the reflection spectrum changes of the grating sensing units in the first, second, third, and fourth optical cables in real time and convert them into strain monitoring data.

[0040] The demodulator 300 employs a multi-channel fiber optic demodulation device, which is connected to the first upstream heavy vehicle trajectory optical cable 210a, the second upstream heavy vehicle trajectory optical cable 210b, the upstream top plate boundary reference optical cable 220a, the upstream bottom plate corresponding optical cable 220b, the first downstream heavy vehicle trajectory optical cable 230a, the second downstream heavy vehicle trajectory optical cable 230b, the downstream top plate boundary reference optical cable 240a, and the downstream bottom plate corresponding optical cable 240b, respectively. It is used to collect the reflection spectrum changes of the grating sensing units in each sensing optical cable in real time and convert them into strain monitoring data on the corresponding measuring lines.

[0041] Furthermore, in this embodiment, the demodulator 300 is a common and readily available fiber optic demodulator 300. The fiber optic demodulator 300 has multi-channel synchronous acquisition capability to ensure that the data of the heavy vehicle trajectory measurement line, the lane intersection reference measurement line and the corresponding measurement line of the base plate 120 have a unified time reference.

[0042] In one embodiment, the data processing unit 400 can synchronize, register, and segment the strain data of the first, second, third, and fourth optical cables in time, and establish a multi-line collaborative benchmark based on historical monitoring data of the bridge's health stage.

[0043] The data processing unit 400 is connected to the fiber optic demodulator 300 via a data cable and is used to receive, store, display and analyze strain monitoring data from each sensing channel.

[0044] Furthermore, the data processing unit 400 can be implemented using an industrial computer, server, or other equipment with data processing capabilities, and has built-in a strain data preprocessing module, a health benchmark model construction module, a feature extraction module, an anomaly determination module, and a result output module.

[0045] In some embodiments, the data processing unit 400 performs time synchronization, position registration, and segment division of the strain data of the first upstream heavy vehicle trajectory optical cable 210a, the second upstream heavy vehicle trajectory optical cable 210b, the upstream top plate boundary reference optical cable 220a, the upstream bottom plate corresponding optical cable 220b, the first downstream heavy vehicle trajectory optical cable 230a, the second downstream heavy vehicle trajectory optical cable 230b, the downstream top plate boundary reference optical cable 240a, and the downstream bottom plate corresponding optical cable 240b according to the spatial layout of each sensing optical cable, and establishes a multi-line collaborative benchmark mode based on the historical monitoring data of the bridge health stage.

[0046] Furthermore, the multi-line collaborative benchmark mode includes the difference benchmark between the two heavy vehicle trajectory optical cables on the same side, the difference benchmark between the heavy vehicle trajectory optical cable and the reference optical cable at the junction of the top plate 110 on the same side, the lateral difference benchmark between the heavy vehicle trajectory optical cables on the upstream and downstream sides, and the collaborative benchmark between the reference optical cable at the junction of the top plate 110 and the corresponding optical cable on the bottom plate 120.

[0047] The data processing unit 400 compares the current monitoring data with the above-mentioned benchmark mode. When the relationship between multiple measurement lines in a certain section deviates continuously, it combines the deviation amplitude, spatial location and duration to provide a warning about the potential local stiffness changes, load transfer path adjustments or fatigue deterioration risks in the area near the weld seam around the connection weld between the U-rib 130 and the top plate 110 or bottom plate 120 in that section.

[0048] In this embodiment, as Figure 3 As shown, the steel bridge deck deterioration detection system based on grating array sensing also includes multiple connecting components 500. Each connecting component 500 includes a structural adhesive layer 510 and a covering reinforcement layer 520. The covering reinforcement layer 520 is connected to the top plate 110, the bottom plate 120, or the U-rib 130 via the structural adhesive layer 510. The covering reinforcement layer 520 and the top plate 110, the bottom plate 120, or the U-rib 130 together form a cavity for accommodating the first optical cable, the second optical cable, the third optical cable, and the fourth optical cable. The structural adhesive layer 510 is connected to the first optical cable, the second optical cable, the third optical cable, and the fourth optical cable.

[0049] The fixing structure consisting of structural adhesive layer 510 and cover reinforcement layer 520 is used to securely lay the grating array sensing optical cable in the area near the weld seam where the U rib 130 connects to the top plate 110 or the bottom plate 120.

[0050] Furthermore, the structural adhesive layer 510 is used to continuously bond each grating array sensing optical cable along a predetermined measurement line to the area near the weld seam around the corresponding connection weld, so that the sensing optical cable can deform in tandem with the U-rib 130 and its adjacent plates; the covering reinforcement layer 520 covers the outside of each sensing optical cable and is cured by structural adhesive to form a composite adhesive layer, so as to improve the anti-peeling ability, protection ability and strain transmission stability of the optical cable after laying.

[0051] In some embodiments, the reinforcing layer 520 is a commercially available and readily procurable carbon fiber cloth, which will not be described in detail here.

[0052] This embodiment also provides a method for detecting the deterioration of steel bridge decks based on grating array sensing. The method utilizes a steel bridge deck deterioration detection system based on grating array sensing, and the specific steps are as follows: According to the bridge structure, the first optical cable, the second optical cable, the third optical cable and the fourth optical cable are laid in sequence; The first optical cable, the second optical cable, the third optical cable and the fourth optical cable are connected to the demodulator 300 via optical fiber patch cords, and the demodulator 300 is connected to the data processing unit 400. The demodulator 300 performs real-time synchronous monitoring of each grating sensing unit in each sensing optical cable, records the changes in its reflection spectrum, and converts it into strain monitoring data on each measuring line. The data processing unit 400 receives monitoring data from the demodulator 300 in real time, and stores, displays and analyzes the data according to the type of survey line and spatial location, thereby obtaining the strain response information of the upstream heavy vehicle trajectory line, the upstream lane intersection reference line, the upstream bottom plate 120 corresponding line, the downstream heavy vehicle trajectory line, the downstream lane intersection reference line and the downstream bottom plate 120 corresponding line along the longitudinal direction of the bridge. Distributed strain data were simultaneously acquired for the 100-load wheel track area of ​​the orthotropic steel bridge deck, the lane boundary reference area, and the corresponding area of ​​the 120-load base plate, providing basic data support for subsequent establishment of a health benchmark model, extraction of multi-line difference characteristics, identification of abnormal sections, and spatiotemporal characterization of degradation.

[0053] In actual use, according to the bridge structure layout requirements, the first upstream heavy vehicle trajectory optical cable 210a, the second upstream heavy vehicle trajectory optical cable 210b, the upstream top plate boundary reference optical cable 220a, the upstream bottom plate corresponding optical cable 220b, the first downstream heavy vehicle trajectory optical cable 230a, the second downstream heavy vehicle trajectory optical cable 230b, the downstream top plate boundary reference optical cable 240a, and the downstream bottom plate corresponding optical cable 240b are laid along the predetermined near-weld area. During the laying process, the area near the weld around the connection weld between the U-rib 130 and the top plate 110 or the bottom plate 120 is ground, cleaned, and rust-removed to remove loose rust, oil, and loose coating. A structural adhesive layer 510 is applied to the treated near-weld area, and each sensing optical cable is attached to the structural adhesive layer 510 along the predetermined measurement line. The outer side of the sensing optical cable is covered with a reinforcing layer 520 and cured with structural adhesive, thus forming a sensing optical cable bonding and fixing structure that combines continuous bonding and external covering protection. Each sensing optical cable is continuously laid out along the periphery of the connecting weld seam near the weld seam area, and passes through the corresponding weld hole 150 when passing through the transverse diaphragm 140.

[0054] Each sensing optical cable is connected to a multi-channel fiber optic demodulator 300 via fiber optic patch cords. The fiber optic demodulator 300 is connected to the data processing unit 400. After the system is operational, the area surrounding the weld seams of the top plate 110, bottom plate 120, and corresponding U-ribs 130 experiences strain response under repeated actual traffic vehicle loads. The fiber optic demodulator 300 performs real-time synchronous monitoring of each grating sensing unit in the eight sensing optical cables, records changes in their reflection spectra, and converts them into strain monitoring data on each measuring line.

[0055] The data processing unit 400 receives monitoring data from the fiber optic demodulator 300 in real time and stores, displays, and analyzes the data according to the survey line type and spatial location. This allows it to obtain strain response information along the longitudinal direction of the bridge, including the upstream heavy vehicle trajectory line, the upstream lane boundary reference line, the corresponding line of the upstream bottom plate 120, the downstream heavy vehicle trajectory line, the downstream lane boundary reference line, and the corresponding line of the downstream bottom plate 120. Through this deployment and acquisition process, the system can simultaneously acquire distributed strain data in the heavy vehicle trajectory area of ​​the orthotropic steel bridge deck 100, the lane boundary reference area, and the corresponding area of ​​the bottom plate 120. This provides fundamental data support for subsequent establishment of a health benchmark model, extraction of multi-survey line difference characteristics, identification of abnormal sections, and spatiotemporal characterization of degradation.

[0056] The system mainly includes an orthotropic steel bridge deck 100 structure, a sensing optical cable bonding and fixing structure, a three-dimensional strain sensing network 200, a fiber optic demodulator 300, and a data processing unit 400. The three-dimensional strain sensing network 200 adopts an eight-line layout, with heavy vehicle trajectory measurement line groups, top plate 110 boundary reference measurement line, and corresponding bottom plate 120 measurement lines set on the upstream and downstream sides, respectively, to simultaneously acquire the distributed strain response of the heavy vehicle wheel track area, the lane boundary reference area, and the corresponding area of ​​the bottom plate 120.

[0057] Furthermore, in some embodiments, the steel bridge deck deterioration detection system based on grating array sensing in the steel bridge deck deterioration detection method includes: a strain data preprocessing module, a health benchmark pattern construction module, a feature extraction module, an anomaly determination module, and a result output module.

[0058] Furthermore, the data processing does not only determine the limits of the absolute strain of a single sensing optical cable, but also conducts a comprehensive analysis based on the relationship between multiple measurement lines, including the heavy vehicle trajectory measurement line, the lane intersection reference measurement line, and the corresponding measurement line of the base plate 120. By establishing a multi-measurement line collaborative benchmark mode under healthy conditions and identifying the continuous deviation of the current monitoring data from the benchmark mode, the system can determine the potential risks of local stiffness changes, load transfer path adjustments, or fatigue deterioration in the near-weld area around the weld connecting the U-rib 130 to the top plate 110 or the base plate 120.

[0059] In some embodiments, the strain data preprocessing module is configured to preprocess the strain monitoring data of the eight sensing optical cables acquired by the fiber optic demodulator 300. The eight sensing optical cables include a first upstream heavy vehicle trajectory optical cable 210a, a second upstream heavy vehicle trajectory optical cable 210b, an upstream top plate boundary reference optical cable 220a, an upstream bottom plate corresponding optical cable 220b, a first downstream heavy vehicle trajectory optical cable 230a, a second downstream heavy vehicle trajectory optical cable 230b, a downstream top plate boundary reference optical cable 240a, and a downstream bottom plate corresponding optical cable 240b.

[0060] Furthermore, preprocessing may include operations such as time synchronization, outlier removal, temperature compensation, location registration, and segment division to improve the comparability of data between different survey lines and between different monitoring cycles.

[0061] Among them, time synchronization is used to ensure that the data of each sensing optical cable can be compared in the same statistical period; position registration is used to map the corresponding measuring points of each measuring line to the same analysis position in the longitudinal direction of the bridge; and segment division is used to divide the longitudinal direction of the bridge into multiple analysis segments according to the 140 spacing of the transverse diaphragm, the distribution position of the 130 U-rib, or the preset length.

[0062] In some embodiments, the health benchmark model construction module is configured to establish a multi-line collaborative benchmark model based on historical strain monitoring data under the bridge's health status.

[0063] Historical data under healthy conditions can be selected from continuous monitoring data during the initial stage of bridge operation when the structure has not deteriorated significantly; this module statistically analyzes the strain response relationship between different measuring lines in each analysis section to obtain a stable relationship pattern characterizing the healthy state.

[0064] Furthermore, the multi-line collaborative benchmark mode includes at least: the same-side dual wheel track stable difference mode, the wheel track area and the boundary reference area stable difference mode, the upstream and downstream heavy vehicle wheel track stable difference mode, and the top-bottom plate 120 collaborative mode between the boundary reference line of the top plate 110 and the corresponding line of the bottom plate 120.

[0065] Among them, the same-side dual-wheel track stability difference mode is used to describe the range of response difference between two heavy vehicle track measurement lines in the same side heavy lane under healthy conditions; the wheel track area and boundary reference area stability difference mode is used to describe the range of response difference between the heavy vehicle track measurement line and the boundary reference measurement line of the same side lane under healthy conditions; the upstream and downstream heavy vehicle wheel track stability difference mode is used to describe the range of lateral response difference between the upstream and downstream heavy vehicle track measurement lines under healthy conditions; the top-bottom plate 120 cooperative mode is used to describe the range of correlation, amplitude ratio or distribution pattern similarity between the top plate 110 boundary reference measurement line and the corresponding measurement line of the bottom plate 120 under healthy conditions.

[0066] In some embodiments, the feature extraction module is configured to extract characterization features corresponding to the multi-line collaborative benchmark mode from the strain monitoring data of the current monitoring period.

[0067] Furthermore, the characterization features include the difference features of the same-side dual wheel tracks, the difference features between the wheel track area and the boundary reference area, the difference features of the upstream and downstream heavy-duty wheel track responses, and the top-bottom plate 120 cooperative features.

[0068] Furthermore, the differences in wheel tracks on the same side can be represented by the peak strain ratio, average strain difference, response amplitude difference, or distribution pattern difference of the two heavy vehicle track measurement lines on the same side within the corresponding analysis section; the differences between the wheel track area and the boundary reference area can be represented by the peak strain ratio, average strain difference, or response amplitude ratio between the heavy vehicle track measurement line and the boundary reference measurement line of the same side lane; the differences in the response of upstream and downstream heavy vehicle wheel tracks can be represented by the peak ratio, mean difference, correlation coefficient, or distribution pattern similarity between the corresponding heavy vehicle track measurement lines on the upstream and downstream sides; the coordination characteristics of the top-bottom plate 120 can be represented by the correlation coefficient, amplitude ratio, or distribution pattern similarity between the boundary reference measurement line of the top plate 110 and the corresponding measurement line of the bottom plate 120. By extracting the above features, the response changes of the steel bridge deck in terms of local differences in the wheel track area, reference area comparison, upstream and downstream lateral differences, and top-bottom plate 120 coordination relationship under the current monitoring state can be obtained, providing a data basis for subsequent anomaly judgment.

[0069] In addition, in some embodiments, the anomaly determination module is configured to compare the characterization features extracted in the current monitoring period with the health benchmark pattern to identify abnormal segments.

[0070] Furthermore, when the difference characteristics of the same-side dual wheel tracks in a certain analysis section continuously deviate from the healthy baseline pattern, or the response difference of the heavy vehicle trajectory measurement line relative to the same-side lane boundary reference measurement line continuously increases, or the relationship between the upstream and downstream heavy vehicle trajectory responses becomes continuously unbalanced, or the correlation between the top plate 110 boundary reference measurement line and the corresponding measurement line of the bottom plate 120 continuously decreases, and the above deviations remain or show an increasing trend in multiple consecutive monitoring cycles, it is determined that there is an abnormal response in that section.

[0071] Furthermore, abnormal responses can be used to indicate that there may be local stiffness changes, enhanced stress redistribution, load transfer path adjustments, increased risk of fatigue deterioration in the wheel track area, or weakened synergy between the top plate 110 and the bottom plate 120 in the area near the weld connecting the U-rib 130 and the top plate 110 or the bottom plate 120. The judgment basis of this module is not the absolute value of strain at a single measuring point exceeding the limit, but a comprehensive identification based on the continuous changes in the differences and synergies between multiple measuring lines.

[0072] In addition, in some embodiments, the result output module is used to output the location, anomaly type, degree of deviation and development trend of the abnormal segment, and generate deterioration risk warning information when the preset conditions are met.

[0073] Furthermore, the location of abnormal sections can be represented by the numbering of diaphragm 140, U-rib 130, connection weld location, heavy vehicle trajectory line number, or bridge longitudinal section number.

[0074] Furthermore, the types of anomalies may include anomalies in the difference between the two wheel tracks on the same side, anomalies in the difference between the wheel track area and the boundary reference area, anomalies in the difference between the wheel track response of the upstream and downstream heavy vehicles, and anomalies in the coordination between the top and bottom plates.

[0075] Furthermore, the degree of deviation can be determined based on the magnitude, proportion, or extent to which the current characteristic value deviates from the healthy baseline model; the development trend can be determined based on the direction and duration of change of the characteristic value over multiple consecutive monitoring periods.

[0076] Furthermore, when abnormal responses occur continuously within the same segment, or when multiple features deviate abnormally at the same time, the result output module generates corresponding early warning information to provide a basis for subsequent manual review, inspection positioning, and maintenance decisions.

[0077] like Figures 1 to 6 As shown, in some embodiments, the specific steps in the implementation process are as follows: After the system is running, the fiber optic demodulator 300 transmits the strain monitoring data collected by the eight sensing optical cables to the data processing unit 400 in real time. The data processing unit 400 calls the strain data preprocessing module to perform time synchronization, outlier removal, temperature compensation and position registration on the data of each measuring line, and completes the division of the analysis section according to the spacing of the diaphragm 140 and the layout position of the U rib 130 or the preset length.

[0078] The data processing unit 400 calls the health benchmark model construction module to extract the characteristic values ​​of each analysis section in each statistical period from the historical monitoring data when the bridge was put into operation and the structure was in a healthy state, and performs statistical processing on them to obtain the benchmark characteristic value and normal fluctuation range corresponding to each analysis section.

[0079] Furthermore, the baseline characteristic values ​​and normal fluctuation ranges are used to describe the stable response relationship between multiple measuring lines under healthy conditions, rather than the fixed strain limit values ​​of a single measuring point. For example, in the analysis section near the No. 5 diaphragm 140, the baseline value of the peak strain ratio between the first downstream heavy vehicle trajectory optical cable 230a and the second downstream heavy vehicle trajectory optical cable 230b is 1.06, with a normal fluctuation range of 0.96 to 1.16; the baseline value of the peak strain ratio between the first downstream heavy vehicle trajectory optical cable 230a and the downstream roof boundary reference optical cable 240a is 1.35, with a normal fluctuation range of 1.22 to 1.48; the baseline value of the correlation coefficient between the downstream roof boundary reference optical cable 240a and the corresponding downstream floor optical cable 240b is 0.90, with a normal fluctuation range of 0.84 to 0.95. These values ​​are only used to illustrate the construction method of the healthy baseline model; the specific values ​​can be determined based on the bridge structure, the location of the sensing optical cables, and the statistical results of actual monitoring data, and will not be elaborated further here.

[0080] During subsequent monitoring, the feature extraction module processes the strain monitoring data of each analysis section within the current statistical period to extract the same-side double wheel track difference features, wheel track area and boundary reference area difference features, upstream and downstream heavy vehicle wheel track response difference features, and top-bottom plate 120 collaborative features.

[0081] Furthermore, taking the monitoring results from day 126 as an example, the data processing unit 400 found that the peak strain ratio between the first downstream heavy vehicle trajectory optical cable 230a and the second downstream heavy vehicle trajectory optical cable 230b in the analysis section near the No. 5 diaphragm 140 increased from the baseline value of 1.06 to 1.21, which has exceeded the upper limit of the normal fluctuation range of 1.16; the peak strain ratio between the first downstream heavy vehicle trajectory optical cable 230a and the downstream top plate junction reference optical cable 240a increased from the baseline value of 1.35 to 1.56, which has exceeded the upper limit of the normal fluctuation range of 1.48. In the subsequent five consecutive statistical periods, the peak strain ratios between the first downstream heavy vehicle track optical cable 230a and the second downstream heavy vehicle track optical cable 230b were 1.24, 1.27, 1.31, 1.35 and 1.39, respectively, and the peak strain ratios between the first downstream heavy vehicle track optical cable 230a and the downstream roof interface reference optical cable 240a were 1.60, 1.64, 1.69, 1.73 and 1.78, respectively, all showing a continuous increasing trend.

[0082] Meanwhile, the correlation coefficient of strain distribution between the reference optical cable 240a at the junction of the downstream top plate and the corresponding optical cable 240b at the downstream bottom plate in this section decreased from the baseline value of 0.90 to 0.82, and then decreased to 0.80, 0.78, 0.76, 0.74 and 0.72 in the following five consecutive statistical periods, remaining below the lower limit of the normal fluctuation range of 0.84.

[0083] Based on the above characteristic change results, the anomaly determination module determined that the same-side double wheel track difference pattern, the wheel track area and boundary reference area difference pattern, and the top-bottom plate 120 cooperative pattern of the analysis section near the No. 5 diaphragm 140 all showed continuous deviation, indicating that there was an abnormal response in this section.

[0084] Furthermore, the abnormal response suggests that there may be local stiffness changes, stress redistribution, or fatigue deterioration risks in the area near the weld seam of the U-rib 130 and the top plate 110 connected by the first heavy vehicle trajectory line on the downstream side, and may further cause changes in the load transfer path and the cooperative force relationship of the top and bottom plates 120.

[0085] The result output module displays and records the location, type, degree of deviation, and development trend of the abnormal section based on the anomaly determination result. In this embodiment, the abnormal location is the area near the weld seam of the U-rib 130 and the top plate 110 connecting weld seam, which corresponds to the first heavy vehicle trajectory line near the No. 5 transverse diaphragm 140 on the downstream side. The abnormal type is the same-side double wheel track difference anomaly, the wheel track area-intersection reference area difference anomaly, and the top-bottom plate 120 coordinated anomaly. The anomaly level is moderate anomaly, and the development trend is continuous aggravation.

[0086] Furthermore, through the above data processing, the system can identify potential abnormal sections from the changes in the coordinated strain response between the heavy vehicle trajectory line, the lane boundary reference line, and the corresponding line of the bottom plate 120, providing a basis for characterizing the deterioration origin, location, and evolution law of the fatigue-sensitive area of ​​the orthotropic steel bridge deck 100.

[0087] To better understand this invention, the following is combined with... Figures 1 to 6 The technical solution of the present invention is described in detail as follows: Compared with the prior art, the first optical cable group 210, the second optical cable group 220, the third optical cable group 230 and the fourth optical cable group 240 arranged along the length direction of the orthotropic steel bridge deck 100 can collect and convert the various reflection spectrum changes in real time through the demodulator 300, and receive, store, display and analyze the various strain monitoring data through the data processing unit 400. Since each sensing optical cable is laid along the entire length of the preset measurement line and the positional relationship of each grating sensing unit is known, after the system detects that the above-mentioned multi-measurement line collaborative index has continuously deviated in a specific section, it can combine the amplitude, spatial location and duration of the abnormal change to correspond the abnormal section to the area near the corresponding U rib 130, connecting weld or transverse diaphragm 140 in the bridge structure model, thereby providing a basis for identifying internal stiffness changes, fatigue damage risks or abnormal structural evolution trends.

[0088] The present invention enables each sensing optical cable to be continuously deployed along the longitudinal direction of the bridge in the area near the weld seam connecting the U-rib 130 and the top plate 110 or the bottom plate 120, thereby continuously acquiring distributed strain information near fatigue-sensitive structures and overcoming the shortcomings of traditional point monitoring which has insufficient spatial coverage and can only reflect local response. Furthermore, this embodiment does not rely solely on the absolute strain value exceeding the limit at a single measuring point for judgment, nor does it use the strain distribution of the top plate 110 and bottom plate 120 to invert the overall deflection or longitudinal displacement of the bridge as the primary objective. Instead, it establishes a health benchmark model based on the response relationship of multiple measuring lines between the heavy vehicle trajectory measuring line, the lane intersection reference measuring line, and the corresponding measuring line of the bottom plate 120. When local stiffness changes, stress redistribution, or load transfer path adjustments occur in the area near the weld around the connection weld between the U-rib 130 and the top plate 110 or bottom plate 120, the aforementioned multi-measuring line relationship may continuously deviate from the health benchmark, thereby providing a basis for early anomaly identification and fatigue deterioration risk warning. Furthermore, this embodiment also introduces the differences in wheel tracks on the same side, the differences between the wheel track area and the lane boundary reference area, the differences in the wheel track responses of upstream and downstream heavy vehicles, and the cooperative relationship between the reference survey line at the top plate 110 and the corresponding survey line at the bottom plate 120. Through cross-validation among multiple features, the influence of vehicle weight, speed, lateral driving position, and random traffic load fluctuations on the judgment results of a single survey line can be reduced, thereby improving the reliability of abnormal response identification and abnormal section location.

[0089] Furthermore, in this embodiment, the sensing optical cable is not simply deployed in the ordinary stiffening rib area far from the weld, but is continuously deployed along the periphery of the weld connecting the U-rib 130 to the top plate 110 or bottom plate 120, close to the weld. This area is close to the structural details of the orthotropic steel bridge deck 100 where fatigue cracks are prone to initiate, allowing for more direct sensing of strain response changes in the structure surrounding the connecting weld. This provides more targeted monitoring data for judging local stiffness changes, load transfer path adjustments, and fatigue deterioration risks.

[0090] Furthermore, this embodiment can establish a multi-line collaborative benchmark mode under the healthy state of the bridge, and by comparing the spatial variation characteristics and temporal evolution trend of the current monitoring data with respect to the benchmark mode, determine the section where the abnormal response is located, the corresponding heavy vehicle trajectory line, the location of the weld connecting the U-rib 130 and the plate and its development trend, thereby realizing the location, tracking and spatiotemporal characterization of the abnormal response in the fatigue sensitive area of ​​the orthotropic steel bridge deck 100.

[0091] Furthermore, the grating array sensing optical cable is laid using a combination of continuous bonding with structural adhesive layer 510 and carbon fiber cloth covering reinforcement. The construction process is clear and easy to implement in the area near the weld seam of the U-rib 130-plate connection weld in the top plate 110 area and bottom plate 120 area of ​​the steel box girder. Structural adhesive layer 510 ensures continuous bonding and strain transfer between the sensing optical cable and the measured structure, while the covering reinforcement layer 520 improves the external protection and peel resistance of the sensing optical cable, thereby improving the reliability and engineering applicability of the system for long-term monitoring.

[0092] This embodiment, through the above-described system and method, can solve the technical problem in the prior art that can only obtain the strain response at discrete measuring points and is difficult to reflect the continuous strain distribution characteristics of fatigue-sensitive structures along the longitudinal direction of the bridge, making it difficult to effectively determine the damage initiation location and its evolution process.

[0093] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A steel bridge deck deterioration detection system based on grating array sensing, configured to be connected to an orthotropic steel bridge deck, the orthotropic steel bridge deck having an upstream side and a downstream side arranged symmetrically, the upstream side and the downstream side respectively including a heavy lane and a light lane, characterized in that, include: The strain sensing network includes a first optical cable group, a second optical cable group, a third optical cable group, and a fourth optical cable group arranged along the length direction of the orthotropic steel bridge deck. The first optical cable group is laid on the heavy-duty lane on the upstream side, the second optical cable group is laid between the heavy-duty lane and the small lane on the upstream side, the third optical cable group is laid on the heavy-duty lane on the downstream side, and the fourth optical cable group is laid between the heavy-duty lane and the small lane on the downstream side. The demodulator is optically connected to the first optical cable group, the second optical cable group, the third optical cable group and the fourth optical cable group respectively, and is used to collect and convert the changes in each reflection spectrum in real time. as well as The data processing unit, connected to the demodulator, is used to receive, store, display, and analyze various strain monitoring data.

2. The steel bridge deck deterioration detection system based on grating array sensing according to claim 1, characterized in that, The orthotropic steel bridge deck includes a top plate, a bottom plate, U-ribs, diaphragms, and weld holes. The bottom plate and the top plate are spaced apart from each other, and a plurality of U-ribs are evenly arranged on the surface of the top plate or the bottom plate. The diaphragms are spaced apart along the longitudinal direction of the orthotropic steel bridge deck, and the diaphragms are provided with weld holes for the passage of sensing optical cables. The first optical cable group includes two first optical cables, which are parallel to each other and spaced apart. They are evenly distributed in the area near the weld seam where the U-ribs and the top plate connect to the heavy vehicle track line in the upstream lane, for obtaining the strain response of the upstream heavy vehicle track area.

3. The steel bridge deck deterioration detection system based on grating array sensing according to claim 2, characterized in that, The second optical cable group includes two second optical cables. One second optical cable is laid in the area near the weld seam of the U-rib connecting the top plate at the junction of the upstream heavy lane and the light lane. The other second optical cable is located below the projection of the first second optical cable and is laid in the area near the weld seam of the U-rib connecting the bottom plate at the junction of the upstream heavy lane and the light lane.

4. The steel bridge deck deterioration detection system based on grating array sensing according to claim 3, characterized in that, The third optical cable group includes two third optical cables, which are parallel to each other and spaced apart. They are evenly distributed in the area near the weld seam where the U-rib and the top plate connect to the heavy vehicle track line in the downstream side lane, and are used to obtain the strain response of the heavy vehicle track area in the downstream side.

5. The steel bridge deck deterioration detection system based on grating array sensing according to claim 4, characterized in that, The fourth optical cable group includes two fourth optical cables. One fourth optical cable is laid in the area near the weld seam of the U-rib connecting the top plate at the junction of the downstream heavy lane and the light lane. The other fourth optical cable is located below the projection of the first fourth optical cable and is laid in the area near the weld seam of the U-rib connecting the bottom plate at the junction of the downstream heavy lane and the light lane.

6. The steel bridge deck deterioration detection system based on grating array sensing according to claim 5, characterized in that, The first, second, third, and fourth optical cables pass sequentially through the welding holes on the diaphragm to form an eight-line three-dimensional strain monitoring network that can cover the heavy vehicle wheel track area, the lane intersection reference area, and the corresponding area of ​​the bottom plate.

7. The steel bridge deck deterioration detection system based on grating array sensing according to claim 6, characterized in that, The demodulator is optically connected to the first, second, third, and fourth optical cables, and is used to collect the reflection spectrum changes of the grating sensing units in the first, second, third, and fourth optical cables in real time, and convert them into strain monitoring data.

8. The steel bridge deck deterioration detection system based on grating array sensing according to claim 5, characterized in that, The data processing unit can synchronize the strain data of the first, second, third, and fourth optical cables in time, register their positions, and divide them into sections, and establish a multi-line collaborative benchmark based on historical monitoring data of the bridge's health stage.

9. The steel bridge deck deterioration detection system based on grating array sensing according to claim 5, characterized in that, The steel bridge deck deterioration detection system based on grating array sensing also includes multiple connecting components. Each connecting component includes a structural adhesive layer and a covering reinforcement layer. The covering reinforcement layer is connected to the top plate, bottom plate, or U-rib via the structural adhesive layer. The covering reinforcement layer and the top plate, bottom plate, or U-rib together form a cavity for accommodating the first, second, third, and fourth optical cables. The structural adhesive layer is connected to the first, second, third, and fourth optical cables.

10. A method for detecting the deterioration of steel bridge decks based on grating array sensing, characterized in that, The specific steps of using the steel bridge deck deterioration detection system based on grating array sensing as described in claims 1 to 9 are as follows: According to the bridge structure, the first optical cable, the second optical cable, the third optical cable and the fourth optical cable are laid in sequence; The first, second, third, and fourth optical cables are connected to the demodulator via fiber optic patch cords, and the demodulator is connected to the data processing unit. The demodulator performs real-time synchronous monitoring of each grating sensing unit in each sensing optical cable, records the changes in its reflection spectrum, and converts it into strain monitoring data on each measuring line. The data processing unit receives monitoring data from the demodulator in real time and stores, displays and analyzes the data according to the type of survey line and spatial location, thereby obtaining the strain response information of the upstream heavy vehicle trajectory line, the upstream lane intersection reference line, the upstream bottom plate corresponding line, the downstream heavy vehicle trajectory line, the downstream lane intersection reference line and the downstream bottom plate corresponding line along the longitudinal direction of the bridge. Distributed strain data of the heavy vehicle wheel track area, lane boundary reference area and corresponding area of ​​the bottom plate of the orthotropic steel bridge deck were acquired simultaneously, providing basic data support for subsequent establishment of health benchmark model, extraction of multi-line difference characteristics, identification of abnormal sections and carrying out spatiotemporal characterization of deterioration.

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