CN109269685B - Concrete stress sensor and application method thereof - Google Patents
Concrete stress sensor and application method thereof Download PDFInfo
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- CN109269685B CN109269685B CN201811225828.1A CN201811225828A CN109269685B CN 109269685 B CN109269685 B CN 109269685B CN 201811225828 A CN201811225828 A CN 201811225828A CN 109269685 B CN109269685 B CN 109269685B
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- 238000000034 method Methods 0.000 title claims abstract description 20
- 238000012360 testing method Methods 0.000 claims abstract description 72
- 230000005291 magnetic effect Effects 0.000 claims abstract description 33
- 230000004907 flux Effects 0.000 claims abstract description 24
- 230000005294 ferromagnetic effect Effects 0.000 claims abstract description 14
- 238000004519 manufacturing process Methods 0.000 claims abstract description 7
- 238000002156 mixing Methods 0.000 claims abstract description 7
- 230000006698 induction Effects 0.000 claims abstract description 5
- 238000002360 preparation method Methods 0.000 claims description 20
- 229910000859 α-Fe Inorganic materials 0.000 claims description 8
- 238000009662 stress testing Methods 0.000 claims description 6
- 239000011248 coating agent Substances 0.000 claims description 3
- 238000000576 coating method Methods 0.000 claims description 3
- 238000012937 correction Methods 0.000 claims description 3
- 239000003822 epoxy resin Substances 0.000 claims description 3
- 239000003292 glue Substances 0.000 claims description 3
- 239000008187 granular material Substances 0.000 claims description 3
- 238000012423 maintenance Methods 0.000 claims description 3
- 229920000647 polyepoxide Polymers 0.000 claims description 3
- 238000003825 pressing Methods 0.000 claims description 3
- 238000001514 detection method Methods 0.000 abstract description 3
- 230000035882 stress Effects 0.000 description 96
- 239000004568 cement Substances 0.000 description 4
- 229910000831 Steel Inorganic materials 0.000 description 3
- 239000000835 fiber Substances 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 239000010959 steel Substances 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 239000003302 ferromagnetic material Substances 0.000 description 2
- 239000000919 ceramic Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 230000006355 external stress Effects 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/12—Measuring force or stress, in general by measuring variations in the magnetic properties of materials resulting from the application of stress
- G01L1/127—Measuring force or stress, in general by measuring variations in the magnetic properties of materials resulting from the application of stress by using inductive means
Abstract
The invention discloses a concrete stress sensor and a using method thereof, and belongs to the field of civil engineering. The concrete stress sensor consists of a left end block, a right end block and a stress test column. The stress test column is made of special concrete, the mixing ratio is the same as that in a concrete structure, only the aggregate in the stress test column is replaced by ferromagnetic aggregate, and the grading of the two aggregates is completely the same. When in stress test, the external magnetic flux tester and the stress sensor form a closed magnetic circuit, and after the exciting coil generates a pulse magnetic field, the induced voltage in the induction coil is measured to obtain the stress in the concrete. The stress sensor is convenient for detecting the concrete stress after the engineering structure is built, can automatically deduct the influence of concrete shrinkage and creep, has simple structure and low manufacturing cost, has the same service life as the engineering structure, can reduce the detection cost of the whole engineering structure, and is economical and practical.
Description
Technical Field
The invention relates to a concrete stress sensor and a using method thereof, belonging to the field of civil engineering.
Background
Currently, stress sensors commonly used in concrete structures can be broadly classified into the following categories: (1) The external stress of the vibrating wire type stress meter changes the tightness degree of the sensor steel wire, the sensor steel wire is made to resonate through an excitation circuit, and the frequency of the steel wire is read, so that a stress value is obtained. (2) The piezoelectric stress sensor uses piezoelectric ceramics as a sensitive unit, and reflects static or quasi-static stress in a concrete structure by measuring equivalent circuit parameters in piezoelectric materials. (3) The wavelength of the light reflected by the fiber grating stress sensor is very sensitive to stress and strain, when the elastic body is stressed, the fiber grating and the elastic body deform together, so that the peak wavelength of the light reflected by the fiber grating shifts, and the strain is sensed by measuring the wavelength shift amount.
According to the working principle of the conventional concrete stress sensor, the current concrete stress test is obtained by measuring the strain and taking the elastic modulus of the concrete into consideration. It follows that, precisely, the current concrete stress sensor is actually a concrete strain gauge. After the concrete material is formed, the shrinkage and creep occur, and thus, the measured concrete strain includes a portion caused by the shrinkage and creep, and the resulting stress is not an actual stress. In practical engineering, people can only accurately test the strain increment generated by short-term load or temporary load, so as to obtain the stress increment. For the real-time stress in the concrete, the change rule of the dry shrinkage and the creep can be measured only by using the manufactured test piece, the strain part corresponding to the dry shrinkage and the creep in the concrete is calculated, the measured total strain is deducted from the strain part, and then the stress in the concrete is calculated. The detection of stresses in concrete structures has been an unsolved problem in the civil industry, and it has been desired to be able to directly measure real stresses in real time in concrete.
Disclosure of Invention
The invention aims to solve the defects and problems in the prior art and provides a concrete stress sensor and a using method thereof.
The invention provides a concrete stress sensor and a use method thereof, wherein the concrete stress sensor consists of a left end block, a right end block and a stress test column positioned between the left end block and the right end block; the stress test column is made of special concrete, the mixing ratio of the stress test column is the same as that of the concrete in a concrete structure, only the aggregates in the stress test column are replaced by ferromagnetic aggregates, and the grading of the two aggregates is the same. The use of the concrete stress sensor is divided into an indoor preparation stage and a field operation stage, and specifically comprises the following steps:
the preparation stage step 1 prepares ferromagnetic granules and prepares ferromagnetic aggregates with the same aggregate gradation as that of concrete in the structure;
preparing a special concrete according to the mixing ratio of the concrete in the structure by adopting the prepared ferromagnetic aggregate in the step 2, and manufacturing a group of stress test columns by using the special concrete;
step 3, coating two end faces of the stress testing column with epoxy resin glue solution, and installing the stress testing column into grooves corresponding to the left end block and the right end block, wherein the positions of the left end block and the right end block correspond to each other, and the passive testing faces of the left end block and the right end block are in the same plane;
step 4 of preparation, namely pressing the manufactured stress sensor by using a pressure tester, classifying the load into 8 stages, and measuring the induced voltage by using a matched magnetic flux tester; the magnetic flux tester consists of a left measuring arm, a right measuring arm and a handle, wherein a left exciting coil is arranged in the left measuring arm, a right exciting coil is arranged in the right measuring arm, an induction coil is arranged in the handle, and the magnetic flux tester is bilaterally symmetrical; during testing, the two active test surfaces of the magnetic flux tester are respectively opposite to the corresponding passive test surfaces of the concrete stress sensor, and are kept closely by force, and the pulse switch is turned on, so that the induced voltage in the magnetic flux tester can be read; according to the test results of a group of stress sensors, establishing a corresponding relation between induced voltage and stress value in concrete, and enabling the magnetic flux tester to output the detected induced voltage and stress simultaneously by setting the magnetic flux tester;
the step 4 of the preparation stage is repeated under different temperatures in the step 5 of the preparation stage, and the temperature correction is carried out on the established relation between the induced voltage and the concrete stress;
the method comprises the following steps of operation step 1, pouring a stress test column and carrying out die maintenance, wherein the five hours before pouring concrete at a measuring part in an engineering;
before the concrete is poured in the operation step 2, the stress test column is taken out, and a concrete stress sensor is manufactured according to the preparation step 3;
the operation step 3 is installed at a preset test position, and is fixed, the two exposed passive test surfaces are positioned on the surface of the designed structure, concrete is poured, and the stress sensor can be started only after the concrete around the stress sensor is completely solidified;
and 4, testing the concrete stress of the position where the stress sensor is positioned by adopting the same method as that of the step 4 in the preparation stage, and obtaining the stress value in the concrete by considering the influence of temperature.
Further, the left and right end blocks are the same fitting, which may be referred to as an end block, which has a flat passive test surface and a recess in the middle of one side. This simplifies the design and manufacture of the end block, and only one specification of end block can be designed for all grades of concrete. The end part of the manufactured stress test column is embedded into the end block, so that the left end block, the stress test column and the right end block are fixed into a whole, and the manufactured stress test column can be conveniently placed at a designated position and embedded into a concrete structure along with concrete pouring.
Further, ferrite is used as the ferromagnetic aggregate. This is because the magnetic permeability of ferrite is much higher than that of ordinary materials. And thus the sensitivity of the stress sensor may be improved.
Further, the two passive test surfaces are exposed on the same surface of the engineering structure and are flush; the exposed passive test surface is flat. This is to ensure that the bonding surface can be closely adhered when the externally matched magnetic flux tester measures. When the stress sensor is manufactured, a special auxiliary tool can be used for positioning the two corresponding end blocks, so that the position accuracy of the two corresponding end blocks is ensured.
The scheme of the invention is mainly based on the following principle: (1) The shrinkage and creep in the concrete mainly occur in the cement paste, and the relation between the shrinkage and creep and the aggregate is small, so that the replacement of the aggregate does not influence the shrinkage and creep of the stress test column; (2) When the concrete is poured, the cement paste in the concrete stress sensor which is just manufactured can be considered to be properly maintained, the shrinkage and the creep do not occur at the moment, the shrinkage and the creep which occur in the stress sensor later represent the shrinkage and the creep of the concrete at the position, in the subsequent loading process, the stress sensor and the concrete at the position represented by the stress sensor are in the same deformation state, the stress state is the same, and the stress of the ferromagnetic aggregate is the stress in the concrete at the position represented by the stress sensor; (3) The cement paste is not a ferromagnetic material, the magnetic conductivity of the cement paste is almost constant, and the ferromagnetic material has different magnetic conductivities in different stress states, so that the magnetic conductivity of the sensor is determined by the stress of the ferromagnetic aggregate; (4) When in measurement, an external magnetic flux tester is utilized, a magnetic field generated by an exciting coil passes through the concrete stress sensor, and an induction coil in the magnetic flux tester is influenced by the magnetic field, so that induced voltage can be generated. The induced voltage is related to the magnetic conductivity of the sensor, namely to the stress of the ferromagnetic aggregate, so that the induced voltage and the stress in the concrete establish a corresponding relation, and is irrelevant to the shrinkage and creep of the concrete in the structure and the special concrete in the stress sensor; (5) Through advanced indoor tests, a corresponding relation curve of the induced voltage and the stress can be established. And determining the stress in the concrete according to the obtained induced voltage. The sensor has low cost, little added cost and the same service life as engineering structure.
The stress sensor is convenient to manufacture, is convenient for detecting the stress of the concrete after the engineering structure is built, and can automatically deduct the influence of the shrinkage and creep of the concrete to obtain the real-time stress; the structure is simple, the manufacturing cost is low, the service life of the device is the same as that of an engineering structure, the detection cost of the engineering structure can be reduced, and the device is economical and practical; the stress sensor and the application method thereof solve the problems of long-term desiring to be solved and pending concrete stress test in the civil engineering field.
Drawings
FIG. 1 is a schematic view of the stress sensor of the present invention after it is embedded in concrete.
FIG. 2 is a schematic diagram of the structure when stress is tested.
Fig. 3 is a schematic main body view of the magnetic flux tester.
The stress sensor in the first embodiment of fig. 4 is schematically shown.
An end block in the first embodiment of fig. 5 is shown in perspective view.
Fig. 6 is a schematic diagram of a stress sensor in a second embodiment.
The end block in the second embodiment of fig. 7 is shown in perspective view.
The marks in the figure are as follows: 1-left end block, 2-right end block, 3-stress test column, 4-concrete, 5-groove, 6-left measuring arm, 7-right measuring arm, 8-handle, 9-active test surface, 10-passive test surface, 15-left exciting coil, 16-right exciting coil, 17-induction coil and 19-concrete.
Detailed Description
The following are specific embodiments of the present invention and the technical solutions of the present invention are described with reference to the accompanying drawings, but the present invention is not limited to these embodiments.
Example 1
The embodiment tests the bottom plate stress in a concrete box girder, wherein the concrete strength of the box girder is C50, the concrete stress sensor is schematically shown in figures 1, 2 and 4, and the concrete stress sensor consists of a left end block 1, a right end block 2 and a stress test column 3 positioned between the left end block 1 and the right end block 2; the stress test column 3 is in the shape of a cylinder, and has the diameter of 100mm and the length of 200mm; the stress test column 3 adopts special concrete, the mixing ratio of which is the same as that of the concrete 4 in the concrete structure, except that the aggregate in the concrete structure is replaced by ferrite, and the grading of the two aggregates is completely the same. The left end block 1 and the right end block 2 are the same fittings and can be collectively called as end blocks, and are made of ferrite. The end block has a thickness of 50mm and has a flat passive test surface 10 and a side with a recess 5 in the middle, see in particular figure 5. The diameter of the groove 5 is 101mm, the depth is 10mm, and the shortest distance to the passive test surface 10 is 30mm. The upper end face of the end block is a passive test face 10, and the transverse length is 160mm.
The implementation of the test concrete stress comprises an indoor preparation stage and a field operation stage, and the concrete stress test method specifically comprises the following steps:
the preparation stage step 1 prepares ferrite granules, and prepares ferrite aggregates with the same aggregate grading as the concrete 19 in the structure;
preparing a group of (three) stress test columns 3 by using the prepared ferrite aggregate according to the mixing ratio of the concrete 19 in the structure;
step 3, coating two end faces of the stress testing column 3 with epoxy resin glue solution, and mounting the stress testing column 3 into grooves 5 corresponding to the left end block 1 and the right end block 2, wherein the positions of the left end block 1 and the right end block 2 correspond to each other, and the passive testing surfaces 10 of the left end block 1 and the right end block 2 are in the same plane;
and step 4, pressing the manufactured stress sensor by using a pressure tester, classifying the load into 8 stages, and measuring the induced voltage by using a matched magnetic flux tester, wherein the induced voltage is shown in fig. 2 and 3. The magnetic flux tester consists of a left measuring arm 6, a right measuring arm 7 and a handle 8, wherein a left exciting coil 15 is arranged in the left measuring arm 6, a right exciting coil 16 is arranged in the right measuring arm 7, and an induction coil 17 is arranged in the handle 8. During testing, the two active test surfaces 9 are respectively opposite to the corresponding passive test surfaces 10, the two active test surfaces are tightly adhered with each other by force, and the pulse switch is turned on, so that the induced voltage in the magnetic flux tester can be read. According to the test results of a group of concrete stress sensors, establishing a corresponding relation between induced voltage and stress values in concrete 19, and enabling the magnetic flux tester to output the detected induced voltage and stress simultaneously by arranging the magnetic flux tester;
and (5) repeating the step (4) of the preparation stage at different temperatures in the step (5) of the preparation stage, and carrying out temperature correction on the established relation between the induced voltage and the concrete stress.
The method comprises the following steps of 1, preparing to pour bottom plate concrete of a part to be tested in engineering for five hours, pouring and manufacturing a stress test column 3, and carrying out die maintenance;
the stress test column 3 is taken out in the operation step 2, and a concrete stress sensor is manufactured according to the preparation step 3;
the operation step 3 is installed at a preset test position, and is fixed, the two exposed passive test surfaces 10 are positioned on the upper surface of a designed bottom plate, concrete 19 is poured, and the concrete stress sensor can be started after the concrete 19 around the stress sensor is completely solidified; a temperature sensor is buried around the concrete stress sensor at the same time;
and 4, testing the stress sensor by adopting the same method as that of the preparation step 4, testing the temperature in the concrete 19, and obtaining the stress value in the concrete 19 by considering the influence of the temperature.
Example two
The present embodiment is a modification of the first embodiment, and is different from the first embodiment in that: the stress test column 3 is prismatic in shape, 200mm in length, square in cross section and 100mm in side length; the shape of the end block was correspondingly changed, the end block was a cube with a height of 160mm, the groove 5 was located in the middle of one side, the cross section was a square with a side length of 101mm, and the depth was 10mm, see fig. 6 and 7.
The foregoing description of the specific embodiments is provided for the purpose of illustration only and is not intended to limit the scope of the claims.
Claims (4)
1. The application method of the concrete stress sensor is characterized by comprising the following steps of: the concrete stress sensor consists of a left end block, a right end block and a stress test column positioned between the left end block and the right end block; the stress test column is made of special concrete; the mixing proportion of the special concrete is the same as that of the concrete in the concrete structure, except that the aggregate in the special concrete is replaced by ferromagnetic aggregate; the grading of the two aggregates is identical; the using method of the concrete stress sensor is characterized in that: the method comprises an indoor preparation stage and a field operation stage, and specifically comprises the following steps:
the preparation stage step 1 prepares ferromagnetic granules and prepares ferromagnetic aggregates with the same aggregate gradation as that of concrete in the structure;
preparing a special concrete according to the mixing ratio of the concrete in the structure by adopting the prepared ferromagnetic aggregate in the step 2, and manufacturing a group of stress test columns by using the special concrete;
step 3, coating two end faces of the stress testing column with epoxy resin glue solution, and installing the stress testing column into grooves corresponding to the left end block and the right end block, wherein the positions of the left end block and the right end block correspond to each other, and the passive testing faces of the left end block and the right end block are in the same plane;
step 4 of preparation, namely pressing the manufactured stress sensor by using a pressure tester, classifying the load into 8 stages, and measuring the induced voltage by using a matched magnetic flux tester; the magnetic flux tester consists of a left measuring arm, a right measuring arm and a handle, wherein a left exciting coil is arranged in the left measuring arm, a right exciting coil is arranged in the right measuring arm, an induction coil is arranged in the handle, and the magnetic flux tester is bilaterally symmetrical; during testing, the two active test surfaces of the magnetic flux tester are respectively opposite to the corresponding passive test surfaces of the concrete stress sensor, and are kept closely by force, and the pulse switch is turned on, so that the induced voltage in the magnetic flux tester can be read; according to the test results of a group of stress sensors, establishing a corresponding relation between induced voltage and stress value in concrete, and enabling the magnetic flux tester to output the detected induced voltage and stress simultaneously by setting the magnetic flux tester;
the step 4 of the preparation stage is repeated under different temperatures in the step 5 of the preparation stage, and the temperature correction is carried out on the established relation between the induced voltage and the concrete stress;
the method comprises the following steps of operation step 1, pouring a stress test column and carrying out die maintenance, wherein the five hours before pouring concrete at a measuring part in an engineering;
before the concrete is poured in the operation step 2, the stress test column is taken out, and a concrete stress sensor is manufactured according to the preparation step 3;
the operation step 3 is installed at a preset test position, and is fixed, the two exposed passive test surfaces are positioned on the surface of the designed structure, concrete is poured, and the stress sensor can be started only after the concrete around the stress sensor is completely solidified;
and 4, testing the concrete stress of the position where the stress sensor is positioned by adopting the same method as that of the step 4 in the preparation stage, and obtaining the stress value in the concrete by considering the influence of temperature.
2. The method of using a concrete stress sensor according to claim 1, wherein: the left end block and the right end block are the same fittings and can be collectively called as an end block, the end block is provided with a flat passive test surface, and the middle part of the other side surface is provided with a groove.
3. The method of using a concrete stress sensor according to claim 2, wherein: the ferromagnetic aggregate is made of ferrite.
4. The method of using a concrete stress sensor according to claim 2, wherein: the two exposed passive test surfaces are positioned on the same surface of the engineering structure and are flush with each other; the exposed passive test surface is flat.
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| CN201811225828.1A CN109269685B (en) | 2018-10-21 | 2018-10-21 | Concrete stress sensor and application method thereof |
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| CN201811225828.1A CN109269685B (en) | 2018-10-21 | 2018-10-21 | Concrete stress sensor and application method thereof |
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| CN113405450A (en) * | 2021-06-01 | 2021-09-17 | 北京科技大学 | Rock concrete structural body stability monitoring and early warning method based on static magnetic field detection |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102426070A (en) * | 2011-12-31 | 2012-04-25 | 交通运输部公路科学研究所 | Device and method for testing along-path stress distribution state of prestressed steel beam |
| CN102680156A (en) * | 2012-05-04 | 2012-09-19 | 东南大学 | Coupled external mounted steel stay rope force detection device and method |
| JP2012229982A (en) * | 2011-04-26 | 2012-11-22 | Toyo Constr Co Ltd | Method and apparatus for health monitoring of concrete structure |
| CN103335605A (en) * | 2013-07-08 | 2013-10-02 | 大连理工大学 | High-durability binder-free packaging optical fiber grating strain sensor and packaging method |
| CN103868630A (en) * | 2014-03-14 | 2014-06-18 | 招商局重庆交通科研设计院有限公司 | Inverse magnetostrictive effect-based suspender tension sensor and tension measuring method thereof |
| CN208805302U (en) * | 2018-10-21 | 2019-04-30 | 郑州大学 | A kind of concrete stress sensor |
-
2018
- 2018-10-21 CN CN201811225828.1A patent/CN109269685B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2012229982A (en) * | 2011-04-26 | 2012-11-22 | Toyo Constr Co Ltd | Method and apparatus for health monitoring of concrete structure |
| CN102426070A (en) * | 2011-12-31 | 2012-04-25 | 交通运输部公路科学研究所 | Device and method for testing along-path stress distribution state of prestressed steel beam |
| CN102680156A (en) * | 2012-05-04 | 2012-09-19 | 东南大学 | Coupled external mounted steel stay rope force detection device and method |
| CN103335605A (en) * | 2013-07-08 | 2013-10-02 | 大连理工大学 | High-durability binder-free packaging optical fiber grating strain sensor and packaging method |
| CN103868630A (en) * | 2014-03-14 | 2014-06-18 | 招商局重庆交通科研设计院有限公司 | Inverse magnetostrictive effect-based suspender tension sensor and tension measuring method thereof |
| CN208805302U (en) * | 2018-10-21 | 2019-04-30 | 郑州大学 | A kind of concrete stress sensor |
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