CN202049004U - Fiber Bragg grating stress measuring device for broken line reinforcement T-beam - Google Patents
Fiber Bragg grating stress measuring device for broken line reinforcement T-beam Download PDFInfo
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- CN202049004U CN202049004U CN2010206646772U CN201020664677U CN202049004U CN 202049004 U CN202049004 U CN 202049004U CN 2010206646772 U CN2010206646772 U CN 2010206646772U CN 201020664677 U CN201020664677 U CN 201020664677U CN 202049004 U CN202049004 U CN 202049004U
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- 230000002787 reinforcement Effects 0.000 title claims abstract description 18
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 37
- 239000010959 steel Substances 0.000 claims abstract description 37
- 238000005259 measurement Methods 0.000 claims abstract description 19
- 239000000835 fiber Substances 0.000 claims abstract description 11
- 239000013307 optical fiber Substances 0.000 claims description 51
- 230000001419 dependent effect Effects 0.000 claims description 7
- 238000012545 processing Methods 0.000 claims description 6
- 239000011440 grout Substances 0.000 abstract 1
- 229910001294 Reinforcing steel Inorganic materials 0.000 description 5
- 230000006835 compression Effects 0.000 description 4
- 238000007906 compression Methods 0.000 description 4
- 238000006467 substitution reaction Methods 0.000 description 4
- 238000006073 displacement reaction Methods 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 230000035945 sensitivity Effects 0.000 description 3
- 230000005483 Hooke's law Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 238000001228 spectrum Methods 0.000 description 2
- 229910000851 Alloy steel Inorganic materials 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 235000012489 doughnuts Nutrition 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000013178 mathematical model Methods 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 238000010008 shearing Methods 0.000 description 1
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Abstract
The utility model relates to a fiber Bragg grating stress measuring device for a broken line reinforcement T-beam, in particular to a strain fiber Bragg grating stress measuring device for steel stranded wire total drawing force of the broken line reinforcement T-beam and stress of concrete at critical positions in the T-beam, which belongs to the field of photoelectronic measurement. The operating principle is that the overall drawing force at an anchor position is applied to a round anchor plate by a clamping sheet tightly clamping the steel stranded wire. The axial force peak value of the prestress steel stranded wire is at the end anchor plate, and Bragg wavelength of fiber Bragg grating adhered to the outer wall of the round anchor plate is shifted when the overall drawing force of the steel stranded wire is changed. In T-beam concrete, a strain sensing structure is drawn to reinforcement bent positions, and concrete grout is poured into a corrugated pipe. The concrete is stressed under load to generate tension strain, and the stain value is measured by the fiber Bragg grating adhered to an inner pipe of the strain sensing structure.
Description
Technical field
The utility model relates to a kind of stress measurement technology of broken-line reinforcement T beam, is specifically related to the distributed measurement device of optical fiber Bragg raster of stress, the strain of a kind of overall pulling capacity of anchored end of measuring broken-line reinforcement T joist steel twisted wire and beam inner concrete.Belong to the photoelectron field of measuring technique.
Background technology
The T section beam middle or small stride use in the highway bridge of footpath comparatively extensive, science of bridge building T beam adopts broken-line reinforcement can make the effect that is subjected to pre-shearing near the part concrete of anchored end, not only control the appearance of beam-ends diagonal crack, and can make the structure external applied load offset concrete pre-stress earlier, this prestress is applied by the anchor head anchor slab, can improve concrete tensile strength indirectly.
At inside concrete, after the steel strand tension prestress, because friction loss and transverse stress are disperseed, the concrete stress distribution of each several part is also inhomogeneous, as in than large span and non-mellow and full bending and asymmetric form structural elements, each position concrete stress has than big difference.Under the concrete pulling compressive strain exceeded the maximum failing load, concrete will ftracture after the ultimate strain of concrete pulling strain 230, compressive strain 1700.Usually, longitudinal tensile presstressed reinforcing steel maximum strain variation is not less than 3.5%, because its measurement range is too big, optical fiber Bragg raster directly can't be sticked on the steel strand wires.
With the immediate material of this patent be that Wang Zhongcang writes " Juancheng Yellow River Bridge steel strand tension and put a process construction monitoring " " scientific and technical innovation Leader " the 28th phase in 2009,69～70.Wherein, utilize resistance strain gage to obtain the tension stress of single steel strand in the concrete.Because the whole pulling capacity of prestress wire imposes on anchor slab by the exposed junction steel strand wires by intermediate plate, its method can only reflect single Local Stress-Strain, can not the whole pulling capacity size of complete reaction steel strand wires.Resistance strain gage belongs to relative measurement method, and what obtain is the variable quantity of tested parameter, is difficult to realize steady in a long-term the measurement.
Summary of the invention
The purpose of this utility model is to utilize optical fiber Bragg raster that a kind of overall pulling capacity of anchored end of broken-line reinforcement T joist steel twisted wire and the stress of beam inner concrete, measurement mechanism of strain measured is provided.
Realize that the technical scheme that the utility model patent purpose is taked is: expose anchored end at each bundle steel strand wires, overall pulling capacity clamps steel strand wires by card and imposes on circular plate anchor; The axle power peak value of prestress wire is at termination anchor slab place, optical fiber Bragg raster is sticked on the anchor slab outside surface, the dependent variable at anchor slab place is converted to the wavelength-shift of optical fiber Bragg raster, optical fiber Bragg raster is connected with signal processing apparatus by optical fiber, utilizes the (FBG) demodulator of signal processing apparatus to draw the shift value of optical fiber Bragg raster centre wavelength.
Anchor slab 23 is fastened on the beams of concrete through fastener hole 24, steel strand wires 26 whole pulling capacities in anchor head position are passed to the cylindrical anchor slab 23 of band circular hole by intermediate plate 22,1 optical fiber Bragg raster 21 is pasted on the circular plate anchor outer wall vertically, optical fiber Bragg raster 21 signals are drawn by optical fiber 27 and are measured overall pulling capacity, the anchor slab axially loaded produces microdeformation, and the optical fiber Bragg raster 21 that this strain is secured on its outer wall is measured.
Fiber grating 31 is pasted on pipe 32 in the perforate, and pipe 32 utilizes flange to be connected with outer tube 33 by screw thread in the perforate, and outer tube is anchored on the interior concrete of corrugated tube 35, and sensor is drawn to measuring point by steel strand wires 35; When concrete prefabricated T beam is subjected to loading.
Principle of work is to clamp steel strand wires in the overall pulling capacity in anchor head position by card and impose on circular plate anchor.The axle power peak value of prestress wire causes that at termination anchor slab place the Bragg wavelength that sticks on the optical fiber Bragg raster on the doughnut dish outer wall produces displacement when the overall pulling capacity of steel strand wires changes.At T beam inside concrete, the strain sensing structure drawn to arrangement of reinforcement cross curved position, be cast in the corrugated tube with concrete grouting.Concrete is subjected to load action and produces the tension and compression strain, and the optical fiber Bragg raster that this dependent variable is secured on the interior pipe of strain sensing structure is measured.
The mathematical model of the utility model patent is as follows:
(1) the overall drawing force measurement of broken-line reinforcement exposed junction anchor slab
When the broken-line reinforcement steel strand wires are subjected to axially to draw at concrete body, during pressure, power is passed to circular plate anchor, its compression chord is:
In the formula, A is the sectional area of circular plate anchor.According to Hooke's law, the pass of axial tension σ and elastic body strain stress is to be expressed as:
σ＝Eε (2)
In the formula (2), E is the elastic modulus of circular plate anchor.(2) formula substitution (1) formula can be got pulling capacity is:
F＝EAε (3)
1 optical fiber Bragg raster is sticked on the circular plate anchor, record strain value
In the following formula, λ
BBe the centre wavelength of optical fiber Bragg raster, Δ λ
BBe wavelength-shift amount, P
e=0.22 is valid round-spectrum number, and ε is the axial strain amount.
Must concern with the optical fiber Bragg raster wavelength-shift obtaining the overall pulling capacity size of prestress wire in (4) formula substitution (3) formula:
Record strain value ε by (4) formula, can calculate the overall pulling capacity of steel strand wires.
(2) the broken-line reinforcement steel strand wires are crossed crook concrete stress, strain measurement
The dependent variable ε that concrete produces under loading
1, the strain sensing structure that this dependent variable is cast in the concrete records, and optical fiber Bragg raster is sticked on the interior pipe of perforate pipe.According to Hooke's law, concrete stress is:
σ
1＝E
1ε
1 (6)
In the formula, E
1Be concrete elastic modulus.Record concrete strain stress according to the strain sensing structure
1, can calculate the suffered stress of each measuring point of concrete.
The utility model beneficial effect is:
1. realized the on-line measurement of whole pulling capacity: the utility model is on steel strand wires bared end anchor slab, optical fiber Bragg raster is attached to its outer wall surface, by the overall drawing force measurement of steel strand wires being converted to measurement to the centre wavelength displacement of optical fiber Bragg raster.
2. if directly optical fiber Bragg raster is sticked on the steel strand wires, longitudinal tensile presstressed reinforcing steel maximum strain variation is not less than 3.5%, exceed the optical fiber Bragg raster measurement range, tubular strain sensing structure is adopted in design, interior pipe is connected with flange with outer tube, the flange of flange can better be fixed in the concrete, optical fiber Bragg raster is encapsulated in the interior pipe, avoided directly contacting, can measure that the concrete pulling strain is that 230 μ ε, compressive strain are the dependent variable of 1700 μ ε scopes under concrete pulling compressive strain limit failing load with concrete.Realize critical positions stress in the beam, the measurement of Strain Distribution formula.And convert thereof into measurement to the displacement of the centre wavelength of optical fiber Bragg raster.
Description of drawings
Figure 1A carries out the stress of overall pulling capacity of broken-line reinforcement T joist steel twisted wire and beam inner concrete, the synoptic diagram of strain measurement basic mode for the utility model.
Figure 1B is a transducer arrangements positional structure synoptic diagram of the present utility model.
Fig. 2 is the sensor installation site structural drawing of the utility model at the whole pulling capacity metering system of exposed junction steel strand wires.
Fig. 3 crosses the sensor installation site structural drawing of crook concrete strain metering system for the utility model steel strand wires in beam.
Embodiment
Wherein: each label list of Figure 1A and Figure 1B is shown: T beam concrete section 1, anchor slab 2, fiber Bragg grating 3, steel strand wires 4, corrugated tube 5.Figure 1B optical fiber Bragg raster measuring point is followed successively by anchor slab, crook curve starting point, mid point of curve, End of Curve, precast beam mid point from left to right.
Each label list of Fig. 2 is shown: fiber grating 21, intermediate plate 22, anchor slab 23, fastener hole 24, corrugated tube 25, steel strand wires 26, optical fiber 27.
Each label list of Fig. 3 is shown: fiber grating 31, interior pipe 32, outer tube 33, flange 34, steel strand wires 35.
See Fig. 1, measuring point is followed successively by anchor slab, crook curve starting point, mid point of curve, End of Curve, precast beam mid point from left to right.
See Fig. 2, anchor slab 23 is fastened on the beams of concrete through fastener hole 24, steel strand wires 26 whole pulling capacities in anchor head position are passed to the cylindrical anchor slab 23 of band circular hole by intermediate plate 22, an optical fiber Bragg raster 21 is pasted on the circular plate anchor outer wall vertically, and optical fiber Bragg raster 21 signals are drawn by optical fiber 27 again.
Be pasted in the perforate in the pipe 32 pipe 32 referring to Fig. 3 fiber grating 31 and utilize flange 34 to be connected with outer tube 33 by screw thread, sensor is drawn to measuring point by steel strand wires 35.
The utility model exposes anchored end at each bundle steel strand wires, and overall pulling capacity clamps steel strand wires by card and imposes on circular plate anchor.The axle power peak value of prestress wire is at termination anchor slab place, optical fiber Bragg raster is sticked on the anchor slab outside surface, the dependent variable at anchor slab place is converted to the wavelength-shift of optical fiber Bragg raster, optical fiber Bragg raster is connected with signal processing apparatus by optical fiber, utilizes the (FBG) demodulator of signal processing apparatus to draw the shift value of optical fiber Bragg raster centre wavelength.
Each position concrete stress difference of the utility model T beam is bigger, select 4 bigger measuring points of concrete stress loss, arrangement of reinforcement steel strand wires broken line starting point, cross the sweep mid point, cross the sweep terminal point, and prefabricated T beam midpoint, optical fiber Bragg raster sticks on to draw to arrangement of reinforcement in the pipe in the perforate of strain sensing structure crosses curved position, and concrete grouting is cast in the corrugated tube.Concrete is subjected to load action generation tension and compression strain band dynamic strain sensing arrangement and produces corresponding strain deformation, obtains the wavelength-shift value that strain causes optical fiber Bragg raster according to (FBG) demodulator, and inverse goes out this position concrete stress value.Realize the corresponding relation of wavelength and concrete stress.
Embodiment: the stress of broken line arrangement of reinforcement T beam is monitored.
1. doughnut plate body: 40CrNiMo alloy steel, cross-sectional area A=1256mm
2, Young ' s modulus is E=210Gpa;
2. the technical parameter of optical fiber Bragg raster is: central wavelength lambda
1=1544.000nm, λ
2=1547.000nm, λ
3=1550.000nm, λ
4=1553.000nm, λ
5=1556.000nm valid round-spectrum is counted p
e=0.22;
3. dispose experiment by accompanying drawing 1,2 and Fig. 3;
4. obtain the centre wavelength of optical fiber Bragg raster with the fiber grating analyser;
5. anchor slab surface measuring point (λ
1=1544.000nm) with correlation parameter substitution (5) formula, when steel strand wires applied peak load 259KN, the wavelength-shift amount was 1182pm, the sensitivity of the pulling capacity of sensor is 5pm/KN.
6. in following calculating, ultimate compressive strain of concrete is 1700 μ ε maximal values, when ultimate tensile strength is 230 μ ε;
7.C50 concrete Young ' s modulus is E=34Gpa;
8. broken-line reinforcement is crossed 4 measuring point (λ of crook diverse location
2=1547.000nm, λ
3=1550.000nm, λ
4=1553.000nm, λ
5=1556.000nm), with correlation parameter substitution (6) formula, during limit compressive strain 1700 μ ε, the wavelength-shift amount is respectively 2051pm, 2055pm, 2059pm, 2063pm, calculates the stressed 58Mpa of being of concrete; During ultimate tensile strength 230 μ ε, wavelength-shift amount 278pm calculates the stressed 9Mpa of being of concrete.
9. the sensitivity of sensor stress is 35pm/Mpa during concrete compression, and the sensitivity of sensor stress is 31pm/Mpa during concrete in tension.
Claims (3)
1. the optical fiber Bragg raster stress measurement device of a broken-line reinforcement T beam is characterized in that exposing anchored end at each bundle steel strand wires, and overall pulling capacity clamps steel strand wires by card and imposes on circular plate anchor; The axle power peak value of prestress wire is at termination anchor slab place, optical fiber Bragg raster is sticked on the anchor slab outside surface, the dependent variable at anchor slab place converts the wavelength-shift of optical fiber Bragg raster to, optical fiber Bragg raster is connected with signal processing apparatus by optical fiber, utilizes the (FBG) demodulator of signal processing apparatus to draw the shift value of optical fiber Bragg raster centre wavelength.
2. according to the optical fiber Bragg raster stress measurement device of the described broken-line reinforcement T of claim 1 beam, it is characterized in that: anchor slab (23) is fastened on the beams of concrete through fastener hole (24), the whole pulling capacity of anchor head position steel strand wires (26) is passed to the cylindrical anchor slab (23) of band circular hole by intermediate plate (22), 1 optical fiber Bragg raster (21) is pasted on the circular plate anchor outer wall vertically, optical fiber Bragg raster (21) signal is drawn by optical fiber (27) and is measured overall pulling capacity, the anchor slab axially loaded produces microdeformation, and the optical fiber Bragg raster (21) that this strain is secured on its outer wall is measured.
3. according to the optical fiber Bragg raster stress measurement device of claim 1 or 2 described broken-line reinforcement T beams, it is characterized in that: fiber grating (31) is pasted on pipe (32) in the perforate, pipe (32) utilizes flange to be connected with outer tube (33) by screw thread in the perforate, outer tube is anchored on the concrete in the corrugated tube (35), and sensor is drawn to measuring point by steel strand wires (35).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010206646772U CN202049004U (en) | 2010-12-17 | 2010-12-17 | Fiber Bragg grating stress measuring device for broken line reinforcement T-beam |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010206646772U CN202049004U (en) | 2010-12-17 | 2010-12-17 | Fiber Bragg grating stress measuring device for broken line reinforcement T-beam |
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| Publication Number | Publication Date |
|---|---|
| CN202049004U true CN202049004U (en) | 2011-11-23 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2010206646772U Expired - Fee Related CN202049004U (en) | 2010-12-17 | 2010-12-17 | Fiber Bragg grating stress measuring device for broken line reinforcement T-beam |
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| Country | Link |
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| CN (1) | CN202049004U (en) |
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2010
- 2010-12-17 CN CN2010206646772U patent/CN202049004U/en not_active Expired - Fee Related
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|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20111123 Termination date: 20141217 |
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| EXPY | Termination of patent right or utility model |