CN113587821A - Optical fiber sensor for monitoring relative slippage of steel-concrete composite structure interface - Google Patents
Optical fiber sensor for monitoring relative slippage of steel-concrete composite structure interface Download PDFInfo
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- CN113587821A CN113587821A CN202110737554.XA CN202110737554A CN113587821A CN 113587821 A CN113587821 A CN 113587821A CN 202110737554 A CN202110737554 A CN 202110737554A CN 113587821 A CN113587821 A CN 113587821A
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- fiber sensor
- composite structure
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- 239000013307 optical fiber Substances 0.000 title claims abstract description 74
- 239000004567 concrete Substances 0.000 title claims abstract description 62
- 238000012544 monitoring process Methods 0.000 title claims abstract description 48
- 239000002131 composite material Substances 0.000 title claims abstract description 46
- 239000002184 metal Substances 0.000 claims abstract description 41
- 238000002168 optical frequency-domain reflectometry Methods 0.000 claims abstract description 32
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 27
- 239000010959 steel Substances 0.000 claims abstract description 27
- 238000005516 engineering process Methods 0.000 claims abstract description 19
- 229920001875 Ebonite Polymers 0.000 claims abstract description 14
- 230000035945 sensitivity Effects 0.000 claims abstract description 7
- 239000003292 glue Substances 0.000 claims description 14
- 239000003822 epoxy resin Substances 0.000 claims description 12
- 229920000647 polyepoxide Polymers 0.000 claims description 12
- 239000000835 fiber Substances 0.000 claims description 4
- 238000003466 welding Methods 0.000 claims description 4
- 239000000463 material Substances 0.000 claims description 2
- 229910001220 stainless steel Inorganic materials 0.000 abstract description 18
- 239000010935 stainless steel Substances 0.000 abstract description 18
- 238000009826 distribution Methods 0.000 abstract description 7
- 230000008901 benefit Effects 0.000 abstract description 6
- 238000004519 manufacturing process Methods 0.000 abstract description 5
- 230000000694 effects Effects 0.000 abstract description 3
- 238000001228 spectrum Methods 0.000 abstract description 2
- 238000005259 measurement Methods 0.000 abstract 1
- 238000010586 diagram Methods 0.000 description 6
- 238000000034 method Methods 0.000 description 3
- 238000006073 displacement reaction Methods 0.000 description 2
- 239000011150 reinforced concrete Substances 0.000 description 2
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000009659 non-destructive testing Methods 0.000 description 1
- 238000004806 packaging method and process Methods 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000000523 sample Substances 0.000 description 1
- 230000003595 spectral effect Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Length Measuring Devices By Optical Means (AREA)
Abstract
The invention relates to an optical fiber sensor for monitoring relative slippage of a steel-concrete composite structure interface based on an OFDR technology, and belongs to the technical field of structural health monitoring. The optical fiber OFDR optical fiber sensor comprises an OFDR optical fiber, hard rubber, a metal shell, a metal sheet and a metal sliding block. The sensor is based on the Rayleigh backscattering principle, when the steel and concrete interface slides relatively, the movement of the stainless steel sliding block generates pressure on the metal inclined plate, the force is transmitted to the OFDR distribution optical fiber through the deformation of the hard rubber, so that the change of an optical fiber strain spectrum signal is caused, and the relation between the sliding amount of the metal sliding block and the optical fiber strain change is established, so that the distributed monitoring of the relative sliding of the steel-concrete composite structure interface is realized. The sensor has the advantages of high measurement precision, distributed effect, simple manufacture, low labor cost, high sensitivity and the like, has wide application prospect and is easy to popularize.
Description
Technical Field
The invention relates to an optical fiber sensor for monitoring relative slippage of a steel-concrete composite structure interface based on an OFDR distributed optical fiber technology, belongs to the technical field of structural health monitoring, and is used for monitoring relative slippage of a steel-concrete composite structure interface.
Background
The steel-concrete composite structure is a novel structure developed on the basis of a steel structure and a concrete structure, fully utilizes the respective advantages of steel and concrete, has remarkable economic benefit and social benefit, and is successfully applied to structures such as a plurality of super high-rise buildings, large-span bridges and the like. In steel-concrete composite structures, particularly composite beams, shear connectors are usually flexible connections, which results in relative displacement of the steel-concrete interface of the composite beam, which has a significant effect on the load-bearing capacity, deformation and seismic performance of the composite beam. Therefore, in order to ensure the safe and normal operation of the structure, the monitoring of the interface slip of the steel-concrete composite structure is essential.
Displacement sensors are often adopted for monitoring the interface slippage of the steel-concrete composite structure, but the precision of measured data is low, arrangement points are discrete, the monitoring of accumulated slippage cannot be realized, and the connection with an instrument is complicated. In addition, the ultrasonic probe can only monitor the slippage of a certain position point, and cannot realize distribution monitoring.
The OFDR optical fiber has the advantages of small size, light weight, strong electromagnetic interference resistance and the like, can achieve the effect of distribution monitoring, and is widely applied to distribution monitoring of strain, temperature and the like.
Disclosure of Invention
In order to solve the technical problems, the invention provides an optical fiber sensor for monitoring relative slippage between steel and concrete interfaces of a steel-concrete composite structure based on an OFDR technology, which has the characteristics of high monitoring precision and simple structure, is distributed along the total length of the steel and concrete interfaces, can provide the distribution of interface slippage along the length of the interfaces, and ensures the coaction of the steel member and the concrete member and the overall safety of the structure.
The technical scheme of the invention is as follows:
an optical fiber sensor for monitoring interface slippage of a steel-concrete composite structure based on an OFDR distributed optical fiber technology comprises a metal shell 1, a metal inclined plate 2, a metal sliding block 3, hard rubber 4, an OFDR optical fiber 5 and epoxy resin glue 9;
the OFDR optical fiber 5 and the hard rubber 4 are bonded by epoxy resin glue 9;
the middle part of the stainless steel shell 1 is divided into two halves, each half can be precisely machined, and as shown in figure 4, the two halves can be assembled into a whole through laser welding;
the height of the thin plate structure at the upper part of the stainless steel sliding block 3 is lower than that of the stainless steel shell 1, so that the sliding is convenient;
the size of the part embedded with the concrete at the upper part of the stainless steel sliding block 3 is adjusted according to the property and the thickness of the poured concrete;
the inclination angle of the stainless steel inclined plate 2 is adjusted according to the actual monitoring precision requirement;
the size and the distance of the stainless steel sliding blocks 3 in the optical fiber sensor 6 and the thickness and the hardness of the hard rubber 4 are adjusted according to the monitoring requirements of the length and the sensitivity of the interface of the composite structure to be detected;
the middle position of the surface of the steel member 8 is grooved and used for placing the optical fiber sensor 6, and the upper surface of the stainless steel shell 1 of the optical fiber sensor is flush with the upper surface of the steel member 8 after the optical fiber sensor is placed;
the optical fiber sensor 6 is arranged in a groove of the steel member 8 and fixed;
the working principle of the invention is as follows:
the principle of the optical fiber sensor for monitoring the relative slippage between steel and concrete interfaces of a steel-concrete composite structure based on the OFDR technology is shown in fig. 7, and when the relative slippage is generated due to insufficient connecting members (such as pin bolts) of the steel-concrete composite structure for connecting a steel member 8 (such as a steel beam) and a concrete member 7 (such as a concrete plate), a stainless steel slider 3 embedded in the concrete moves together with the concrete. Because the stainless steel sliding block 3 is embedded into the stainless steel upper thin plate, the stainless steel sliding block 3 can generate downward pressure F' to the stainless steel inclined plates 2 on the two sides, so that the hard rubber 4 pressed by the stainless steel inclined plates 2 is caused to further press the OFDR optical fiber 5 in the hard rubber 4, and strain spectrum signals in the optical fiber are changed. The relative slippage of the interface of the steel concrete structure concrete 7 and the steel component 8 is monitored by establishing the relationship between the slippage of the stainless steel slide block 3 and the strain change of the OFDR distributed optical fiber 5. A plurality of stainless steel sliding blocks 3 are arranged along the length direction of the sensor, so that the distribution monitoring of the relative slippage of the interface along the interface of the steel and concrete composite structure steel 8 and the concrete 7 can be realized. The sensitivity of the interface to the sliding fiber sensor depends on the thickness and hardness of the inner rubber 4, the size and spacing of the metal slider 3.
The invention has the beneficial effects that:
(1) the OFDR optical fiber is bonded with the rubber, and once the rubber is pressed, the OFDR optical fiber can be subjected to pressure to generate spectral signal change, so that the OFDR optical fiber has higher sensitivity.
(2) Due to the characteristic of small structure, after the steel-concrete composite structure is embedded, the bonding performance of the steel-concrete composite structure cannot be greatly influenced, and the nondestructive testing of interface slippage is realized to a greater extent.
(3) The method has strong anti-interference performance and higher resolution, and can realize high-precision monitoring of the interface slippage distribution condition of the reinforced concrete composite structure.
(4) The monitoring sensitivity of the invention depends on the thickness and hardness of the internal rubber, the size and spacing of the stainless steel sliders.
(5) The method is simple to operate, convenient to arrange and simple and convenient to manufacture, can be used for carrying out relevant research in a laboratory and monitoring the slippage of a large-scale steel-concrete combined structure in real time, is suitable for popularization, and has a relatively high application prospect.
Drawings
FIG. 1 is a cross-sectional view of an optical fiber sensor 1-1 for monitoring interface slippage of a steel-concrete composite structure based on OFDR technology in accordance with the present invention;
FIG. 2 is a top view of an optical fiber sensor for monitoring the interface slippage of a steel-concrete composite structure based on OFDR technology according to the present invention;
FIG. 3 is a 3D schematic diagram of an optical fiber sensor for monitoring interface slippage of a steel-concrete composite structure based on OFDR technology according to the present invention;
FIG. 4 is a three-dimensional cross-sectional view of a metal shell of an optical fiber sensor for monitoring interface slippage of a steel-concrete composite structure based on OFDR technology according to the present invention;
FIG. 5 is a perspective view of a metal slider of an optical fiber sensor for monitoring interface slippage of a steel-concrete composite structure based on OFDR technology according to the present invention;
FIG. 6 is a cross-sectional view of an optical fiber sensor 2-2 for monitoring the interface slippage of a steel-concrete composite structure based on OFDR technology according to the present invention;
FIG. 7 is a schematic diagram of the working principle of the optical fiber sensor for monitoring the interface slippage of the steel-concrete composite structure based on the OFDR technology, wherein the left diagram is before the interface slippage relatively, and the right diagram is after the interface slippage relatively;
FIG. 8 is a schematic diagram of an optical fiber sensor engineering installation layout for monitoring interface slippage of a steel-concrete composite structure based on OFDR technology according to the present invention;
in the figure: 1 a metal housing; 2, a metal inclined plate; 3, a metal sliding block; 4, hard rubber; 5OFDR optical fiber; 6, an optical fiber sensor for monitoring the interface slippage of the steel-concrete composite structure based on the OFDR technology; 7, concrete; 8 steel members (e.g., steel beams); 9, epoxy resin glue; 10 fiber optic demodulator.
Detailed Description
In order to make the objects, features and advantages of the present invention more intuitive and understandable, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention, and it is obvious that the embodiments described below are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
As shown in fig. 1-8, an optical fiber sensor for monitoring interface slippage of a steel-concrete composite structure based on OFDR technology comprises a metal housing 1, a metal inclined plate 2, a metal sliding block 3, a hard rubber 4, an OFDR optical fiber 5, and an adhesive 9;
the OFDR optical fiber 5 and the hard rubber 4 can be bonded by epoxy resin glue 9;
the middle part of the metal shell 1 is divided into two halves, each half can be precisely machined, and as shown in figure 1, the two halves can be assembled into a whole through laser welding;
the height of the sheet structure at the upper part of the metal sliding block 3 is lower than that of the metal shell 1, so that the metal sliding block is convenient to slide;
the protruding part of the upper part of the metal sliding block 3 embedded with the concrete is adjusted according to the property and the thickness of the concrete material;
the inclined angle of the metal inclined plate 2 can affect the monitoring precision and the spatial resolution, and the specific angle is adjusted according to actual needs;
the size of the space between the metal sliding blocks 3 in the optical fiber sensor 6 and the thickness and hardness of the hard rubber 4 are adjusted according to the requirements of the length and sensitivity of the interface of the composite structure to be measured;
the middle position of the surface of the steel beam 8 is grooved and used for placing the optical fiber sensor 6, and the upper surface of the metal shell 1 of the optical fiber sensor is flush with the upper surface of the steel beam 8 after the optical fiber sensor is placed;
the optical fiber sensor 6 is arranged in the groove of the steel beam 8 and then can be fixed by epoxy resin glue 9, and the part of the metal sliding block 3 is avoided when the glue is applied;
in an embodiment of the present invention, a method for manufacturing an optical fiber sensor for monitoring interface slippage of a steel-concrete composite structure based on an OFDR technology includes any one of the optical fiber sensors for monitoring interface slippage of a steel-concrete composite structure based on the OFDR technology, and includes the following steps:
step 1: and selecting the distributed single-mode optical fiber with proper length according to the size requirement of the steel-concrete composite structure.
Step 2: in order to facilitate the arrangement of the optical fiber, the rubber is equally divided into blocks in equal volume, the rubber below each sliding block is taken as one block, the rubber blocks are manufactured according to the shapes and the sizes of the blocks shown in the figures 2 and 3, the thickness and the hardness of the rubber are determined according to the specific accuracy requirement of monitoring, after the manufacturing is finished, the opening is formed in the lower portion of each rubber block according to the size of the optical fiber, and the size of the opening can meet the requirement that the optical fiber penetrates through the opening.
And step 3: and (3) penetrating the manufactured rubber block through the optical fiber, filling epoxy resin glue at the rubber opening after the rubber block is penetrated to a specified position, filling the gap with the epoxy resin glue, and then performing the penetration connection of the next rubber block.
And 4, step 4: and after the rubber blocks are completely penetrated and filled with epoxy resin glue, adhering a metal inclined plate on the slope at the upper part of the rubber by using the epoxy resin glue.
And 5, placing the prepared metal slide block on each corresponding rubber block.
Step 6: and (3) splicing the metal shells according to the diagrams of FIGS. 1-4, and performing laser welding on the spliced positions to finish the packaging of the sensor.
And 7: and protecting the optical fibers extending out of the two ends of the optical fiber sensor by adopting a plastic rubber tube, and thus, manufacturing the optical fiber sensor for monitoring the interface slippage of the reinforced concrete composite structure based on the OFDR technology.
And 8: and (4) slotting in the middle of the upper surface of the steel beam, wherein the slotting depth is required to meet the condition that the optical fiber sensor is placed into a horizontal thin stainless steel plate and the surface of the steel beam are parallel and level, and only the protruding part of the sliding block is exposed.
And step 9: and (3) pouring concrete on the upper part of the steel beam, after the pouring is finished, burying one end of the optical fiber into the optical fiber matching paste, and connecting the other end of the optical fiber into the optical fiber demodulator, so that the relative slippage of the structural interface can be monitored in real time.
The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (8)
1. An optical fiber sensor for monitoring interface slippage of a steel-concrete composite structure based on an OFDR technology is characterized by comprising a metal shell (1), a metal inclined plate (2), a metal sliding block (3), hard rubber (4), single-mode optical fibers (5) and epoxy resin glue (9);
the single-mode optical fiber (5) and the hard rubber (4) are bonded by epoxy resin glue (9).
2. The fiber sensor for monitoring the interface slippage of the steel-concrete composite structure according to claim 1, wherein the middle part of the metal shell (1) is divided into two halves, each half can be precisely machined, as shown in fig. 1, and the two halves can be assembled into a whole by laser welding.
3. The optical fiber sensor for monitoring the interface slippage of the steel-concrete composite structure according to claim 2, wherein the upper thin plate structure of the metal sliding block (3) is lower than the metal shell (1) in height so as to facilitate the sliding.
4. The fiber sensor for monitoring the interface slippage of the steel-concrete composite structure according to claim 1 or 2, wherein the protruding portion of the upper part of the metal slider (3) embedded in the concrete is adjusted according to the property and thickness of the concrete material.
5. The optical fiber sensor for monitoring the interface slippage of the steel-concrete composite structure according to claim 1, wherein the inclination angle of the metal inclined plate (2) is adjusted according to the requirements of monitoring precision and spatial resolution.
6. The optical fiber sensor for monitoring the interface slippage of the steel-concrete composite structure according to claim 1, wherein the size of the metal sliding blocks (3) and the distance between the metal sliding blocks and the thickness and the hardness of the hard rubber (4) are adjusted according to the requirements of the interface length and the sensitivity of the composite structure to be detected.
7. The optical fiber sensor for monitoring the interface slippage of the steel-concrete composite structure according to claim 1, wherein a groove is formed in the middle of the surface of the steel beam (8) for placing the optical fiber sensor (6), and the upper surface of the metal shell (1) of the optical fiber sensor is flush with the upper surface of the steel beam (8) after the optical fiber sensor is placed.
8. The optical fiber sensor for monitoring the interface slippage of the steel-concrete composite structure according to claim 1 or 7, wherein the optical fiber sensor (6) is fixed by epoxy resin glue (9) after being placed in the groove of the steel beam (8), and the part of the metal sliding block (3) is avoided when the glue is applied.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202110737554.XA CN113587821A (en) | 2021-06-30 | 2021-06-30 | Optical fiber sensor for monitoring relative slippage of steel-concrete composite structure interface |
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| CN202110737554.XA CN113587821A (en) | 2021-06-30 | 2021-06-30 | Optical fiber sensor for monitoring relative slippage of steel-concrete composite structure interface |
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
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| CN105842148A (en) * | 2016-06-03 | 2016-08-10 | 安徽工业大学 | Sensor for monitoring corrosion state of reinforcing steel bars, production process of sensor and monitoring method for corrosion of reinforcing steel bars |
| CN208805170U (en) * | 2018-02-06 | 2019-04-30 | 上海光栅信息技术有限公司 | A kind of civil engineering fiber grating expansion joint test device |
| JP2019109164A (en) * | 2017-12-19 | 2019-07-04 | 太平洋セメント株式会社 | Stress monitoring sensor and stress monitoring method |
| CN112761195A (en) * | 2021-01-18 | 2021-05-07 | 中铁五局集团第五工程有限责任公司 | Foundation pit concrete beam support body crack monitoring device and monitoring method thereof |
-
2021
- 2021-06-30 CN CN202110737554.XA patent/CN113587821A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101122478A (en) * | 2007-09-13 | 2008-02-13 | 哈尔滨工业大学 | Optical fibre grating flushing monitoring sensor and its manufacture method |
| CN202083358U (en) * | 2010-11-17 | 2011-12-21 | 欧进萍 | Fiber grating embedded type bituminous concrete strain sensor |
| CN105842148A (en) * | 2016-06-03 | 2016-08-10 | 安徽工业大学 | Sensor for monitoring corrosion state of reinforcing steel bars, production process of sensor and monitoring method for corrosion of reinforcing steel bars |
| JP2019109164A (en) * | 2017-12-19 | 2019-07-04 | 太平洋セメント株式会社 | Stress monitoring sensor and stress monitoring method |
| CN208805170U (en) * | 2018-02-06 | 2019-04-30 | 上海光栅信息技术有限公司 | A kind of civil engineering fiber grating expansion joint test device |
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Application publication date: 20211102 |