CN202599578U - Device for measuring effective stress level of vertical prestressed reinforcing steel bar - Google Patents
Device for measuring effective stress level of vertical prestressed reinforcing steel bar Download PDFInfo
- Publication number
- CN202599578U CN202599578U CN 201220149927 CN201220149927U CN202599578U CN 202599578 U CN202599578 U CN 202599578U CN 201220149927 CN201220149927 CN 201220149927 CN 201220149927 U CN201220149927 U CN 201220149927U CN 202599578 U CN202599578 U CN 202599578U
- Authority
- CN
- China
- Prior art keywords
- reinforcing bar
- vertical prestressing
- prestressing reinforcing
- temperature
- ultrasonic
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Images
Landscapes
- Force Measurement Appropriate To Specific Purposes (AREA)
Abstract
Provided is a device for measuring the effective stress level of a vertical prestressed reinforcing steel bar. An ARM processor is connected with an ultrasonic pulse generator. A pulse signal emitted from the ultrasonic pulse generator is transmitted to an ultrasonic transducer via a booster circuit and an emission circuit. Ultrasonic waves are transmitted to a data buffer by the ultrasonic transducer via a programmable filter, a programmable amplifier and an A/D converter. Collected signals are transmitted to a DSP by the data buffer and then are stored in an RAM memory area by the DSP. The ARM processor is connected with a memory, a keyboard, a display, the programmable amplifier, the programmable filter, the RAM memory area and a temperature measurement circuit which is connected with a temperature sensor. The device of the utility model has the characteristics of no loss, high speed, high precision and low cost, enables quantization of a measurement result of the effect of the temperature on the stress, corrects the error in measurement of the effective stress level of a vertical prestressed reinforcing steel bar, and obtains a value of the effective stress level of the vertical prestressed reinforcing steel bar, with engineering precision.
Description
Technical field
The utility model belongs to the Non-Destructive Testing field, relates to a kind of device that is applied in the vertical prestressing reinforcing bar effective stress horizontal checkout of case web.
Background technology
The vertical prestressing bar of bridge structure acts in the case web (web of large-span concrete case beam); Be the key constructs of bearing cross section shear stress and principal tensile stress, in bridge construction, because the case depth of beam is limited; The length of vertical prestressing bar (with respect to the longitudinal prestressing reinforcing bar) is shorter; Thereby the elongation of reinforcing bar is limited when reaching control stress for prestressing, if in anchoring and the anchoring process off normal is arranged slightly, very easily causes the effective stress level can not meet design requirement even stress failures; Receive the influence of construction technology, manual operation method, initial tensioning is not in place and anchoring nut screwing clamping power is not enough, can cause stress failures too.Solve the vertical prestressing loss the most directly, valid approach researches and develops a kind of harmless, fast and accurate effective stress horizontal checkout device and method of testing thereof exactly; Solution vertical prestressing reinforcing bar stress identification technical barrier in work progress and in the operation process is significant to permanance and the reliability that prevents prestressed concrete box-beam bridge web cracking, raising case beam.
The detection method of vertical prestressing reinforcing bar effective stress level has stretch-draw lifting jack oil meter mensuration, presstressed reinforcing steel elongation mensuration, dial torque wrench method, resistance strain gage electrical measuring method, pressure transducer method of testing, frequency method, vibrating wave method, elasticity magnetic (magnetic flux) method etc. at present.Wherein oil meter mensuration, elongation mensuration are the most frequently used method of construction, but measuring accuracy is lower, can't test the vertical prestressing reinforcing bar that own stretch-draw finishes; The dial torque wrench method is more general a kind of method of measuring and controlling the reinforcing bar pretightning force; But there is the serious stress concentration phenomenon in screw thread steel in connecting; Material at regional areas such as ridge roots always produces bigger elastic-plastic deformation, and this brings certain error also for the control pretightning force; Resistance strain gage is used for laboratory measurement more, only can reflect the stress of tested rebar surface, receives the influence of stress raisers phenomenon equally; And the surface that tights a bolt can produce certain shearing deformation; Cause measurement result and actual axial stress that deviation is arranged, complicated condition in the construction work is prone to lose efficacy; The pressure transducer expense is high, from great, and can not reuse, though measuring accuracy is higher, the vertical prestressing number of steel bars is numerous in the web of concrete box girder, can't promote the use of on a large scale, only limits to check verification and scientific research; Grating sensor has advantages such as light weight, high, corrosion-resistant, the anti-electromagnetic interference (EMI) of volume sluggishness, transmission band broad; Be convenient to realize time-division or frequency division multiplex, can carry out the real-time measurement of high capacity information, make the prestress detection of large scale structure become possibility; But grating sensor is installed complicated; Receive the influence of reinforcing bar distortion, sensor is fragile with lead-in wire, and survival rate is not high.Utilize frequency method test pre-tension can reach very high precision; And has advantage simple to operate, that expense is low and equipment can reuse; In case but vertical prestressing reinforcing bar sealing off and covering anchorage just is difficult for the vibration signal under the acquisition excitation, is not suitable for the long term monitoring of vertical prestressing reinforcing bar.Vibrating wave method utilizes vibration wave at transmission speed on the tensioning string and the corresponding relation between the string tension, calculates the pre-tension of vertical prestressing reinforcing bar, and boundary condition is complicated, and measuring accuracy awaits improving; Elasticity magnetic (magnetic flux) method, higher for contactless measurement means measuring accuracy, but need in structure, to desire to bury sensor, owing to cost an arm and a leg, the demarcation of stress and integral voltage is comparatively complicated, measuring accuracy awaits verifying, and is less in application in engineering at present.
Based on the acoustic elasticity principle, hyperacoustic spread speed can produce small variation because of the STRESS VARIATION in the material, through the relation of research axial stress and ultrasonic propagation time rate of change, can utilize ultrasonic wave to measure the stress of material internal.The length of vertical prestressing reinforcing bar is generally 2～12m; The design stretching force is generally 40～60t; With respect to the bolt of usefulness mechanically, length is big, and stress level is high; Environment for use is complicated in the building course and after becoming the bridge operation, the effective stress level receive reinforcing bar and ground tackle connection, apply prestressing techniques, pipeline pneumatic mortar quality etc. and influence bigger.Utility model patent CN1420345A, utility model patent CN2272575Y, ultrasonic bolt fastening force proving installation; Through measuring hyperacoustic velocity of propagation (or travel-time); Obtain the method for bolt stress indirectly, but the energy of transducer little, can only satisfy the such distance of bolt 20-50cm, can not satisfy the long range measurements of deformed bar 2-12m; Hyperacoustic energy attenuation is very big; Do not quantize the susceptibility of temperature counter stress measuring accuracy, the stress measurement error is bigger, can't satisfy the test request of vertical prestressing reinforcing bar.
The utility model content
The purpose of the utility model provides a kind of vertical prestressing reinforcing bar effective stress horizontal checkout device and method of testing thereof, solve the technical matters of vertical prestressing reinforcing bar effective stress horizontal checkout in the case web; And how solution quantizes the problem that influences of temperature counter stress measuring accuracy.
For realizing above-mentioned purpose, the utility model adopts following technical scheme:
A kind of vertical prestressing reinforcing bar effective stress horizontal checkout device comprises ultrasonic transducer, ultrasonic pulse generator, booster circuit, radiating circuit, programmable filter, programmable amplifier, A/D converter, data buffer, DSP, clock counter, RAM memory block, temperature measurement circuit, temperature sensor, arm processor, storer, keyboard and display.
Said ultrasonic transducer is adsorbed on the horizontal section of vertical prestressing reinforced bar stretching end, and said temperature sensor is adsorbed on the side of the revealed section of vertical prestressing reinforcing bar.
The signal output part of said arm processor connects the signal input part of ultrasonic pulse generator, and the pulse signal that the ultrasonic pulse generator sends is sent to the signal input part of ultrasonic transducer through booster circuit and radiating circuit; The signal output part of said ultrasonic transducer is sent to data buffer with ultrasound wave through programmable filter, programmable amplifier and A/D converter; Said data buffer is sent into the signal that collects among the DSP, said DSP with the signal storage that collects to the RAM memory block; Said arm processor all is connected with temperature measurement circuit with storer, keyboard, display, programmable amplifier, programmable filter, RAM memory block; The output terminal of said temperature measurement circuit is connected with arm processor, and the input end of temperature measurement circuit connects temperature sensor.
Said display is used for showing in real time the ultrasonic scanning waveform, hyperacoustic the time, the stress state test result of vertical prestressing reinforcing bar.
Said keyboard is used for the external data input.
Said storer is used to store vertical prestressing reinforcing bar temperature effect coefficient, material influence coefficient, calibration formula and result of calculation.
Said ultrasonic transducer is used to transmit and receive 1 to 20 periodically ultrasonic signal, and said ultrasonic transducer is a piezoceramic transducer, and the outerwrap layer is a magnetic material.
Said temperature sensor is magnetic right cylinder sensing element, is used to gather the temperature value of vertical prestressing reinforcing bar; Said temperature sensor is connected through temperature measurement circuit with arm processor, and said arm processor is used for the result of calculation of vertical prestressing reinforcing bar is carried out the temperature correction.
Said arm processor is used for closing of programmable amplifier and opens time sequence control and the frequency control of programmable filter, and the data sampling speed of said A/D converter is 1Gsps.
Compared with prior art the utlity model has following characteristics and beneficial effect:
The utility model is that the effective stress level that is difficult to the case web vertical prestressing reinforcing bar of quantitative test provides proving installation.Vertical prestressing reinforcing bar effective stress horizontal checkout Design of device is guaranteed the validity and the stability of signal; When ultrasound wave carries out echo reflection after the vertical prestressing reinforcing bar is transmitted to stiff end, behind the ultrasonic transducer reception ultrasound echo signal, export signal to programmable filter; Programmable filter with interfering clutter, noise attentuation after; The output terminal of programmable filter connects programmable amplifier, and signal is fully amplified, and suppresses the level propagation backward of noise and large-signal, limit noise; And can carry out automatically apart from gain compensation ultrasound echo signal, can ultrasound echo signal several times be amplified to essentially identical amplitude level.In addition, in the application of force process of vertical prestressing reinforcing bar, whole device makes the stretch-draw quality of vertical prestressing reinforcing bar have measurability, controllability; Can can't harm, measure fast, precisely, cheaply the vertical prestressing reinforcement construction and become the stress state after bridge is runed, and the travel-time of ultrasonic scanning waveform, sound wave, the effective stress state verification visual result of vertical prestressing reinforcing bar shown through ARM disposal system and display.
The utility model is the basis with the ultrasound wave principle, obtains stress through detecting sonic velocity change, can eliminate the influence of friction force to torque measurement fully, can intuitively react the stress state of vertical prestressing reinforcing bar really; Can play the effect of inspection to the fastening vertical prestressing reinforcing bar of stretch-draw.
The utility model considers that the following anchored end of vertical prestressing is anchored in the concrete; Before not making deck paving; When carrying out the ultrasonic measurement of vertical prestressing reinforcing bar, can be at the ultrasonic transducer that end face is installed transceiver that exposes of reinforcing bar, ultrasonic probe is repeatable to be utilized; Also can select the vertical prestressing reinforcing bar of crucial force part; Like embedding nonvolatil ultrasonic probes such as beam-ends, span centre zones, the connecting line of ultrasonic probe is drawn, be convenient to into the lasting tracking of reinforcement stresses level behind the bridge.
The utility model has been used a kind of clock counter based on ARM; The ultrasonic waves transducer can be launched 1～20 periodic ultrasonic signal; The operating distance of ultrasonic transducer is greater than 35m; Measuring accuracy can reach 0.01ns, the yield strength of the horizontal 1Mpa～reinforcing bar of stress measurement, the relative error of stress measurement≤5%.
Description of drawings
Below in conjunction with accompanying drawing the utility model is done further detailed explanation.
Fig. 1 is the structured flowchart of the vertical prestressing reinforcing bar effective stress horizontal checkout device of the utility model.
Fig. 2 is the effective stress level and sound time difference relation curve of the pulling test vertical prestressing reinforcing bar of the utility model.
Fig. 3 is the size regulation figure of the effective stressed length of vertical prestressing reinforcing bar of the utility model.
Fig. 4 is the temperature and sound time difference relation curve of the humid test vertical prestressing reinforcing bar of the utility model.
Fig. 5 is that the test of the vertical prestressing reinforcing bar of the utility model connects synoptic diagram.
Fig. 6 is the ultrasound echo signal figure of the utility model.
Reference numeral: 1-ultrasonic transducer; 2-ultrasonic pulse generator; The 3-booster circuit; The 4-radiating circuit; The 5-programmable filter; The 6-programmable amplifier; The 7-A/D converter; The 8-data buffer; 9-DSP; The 10-clock counter; The 11-RAM memory block; The 12-temperature measurement circuit; The 13-temperature sensor; The 14-ARM processor; The 15-storer; The 16-keyboard; The 17-display; The 18-cycle is the continuous ultrasound ripple signal of TA; 19-vertical prestressing reinforcing bar; The 20-ultrasound echo signal; The 21-time gate; Anchor plate on the 22-vertical prestressing reinforcing bar; Anchor plate under the 23-vertical prestressing reinforcing bar; The fastening nut of 24-vertical prestressing reinforcing bar; 25-case web; 26-vertical prestressing reinforcing bar effective stress horizontal checkout device; 27-stretch-draw end; The 28-stiff end.
Embodiment
Embodiment is referring to shown in Figure 1, the structured flowchart of the vertical prestressing reinforcing bar effective stress horizontal checkout device of the utility model.This vertical prestressing reinforcing bar effective stress horizontal checkout device comprises ultrasonic transducer 1, ultrasonic pulse generator 2, booster circuit 3, radiating circuit 4, programmable filter 5, programmable amplifier 6, A/D converter 7, data buffer 8, DSP9 (handling the microprocessor of bulk information with digital signal), clock counter 10, RAM memory block 11, temperature measurement circuit 12, temperature sensor 13, arm processor 14, storer 15, keyboard 16 and display 17.
Said ultrasonic transducer 1 is adsorbed on the horizontal section of vertical prestressing reinforcing bar 19 stretch-draw ends 27, and ultrasonic transducer is a piezoceramic transducer, and the outerwrap layer is a magnetic material, is used to transmit and receive 1 to 20 periodically ultrasonic signal.Said temperature sensor 13 is adsorbed on the side of the revealed section of vertical prestressing reinforcing bar 19.
The signal output part of said arm processor 14 connects the signal input part of ultrasonic pulse generator 2, and the pulse signal that ultrasonic pulse generator 2 sends is sent to the signal input part of ultrasonic transducer 1 through booster circuit 3 and radiating circuit 4; The 14 control ultrasonic pulse 1 generation cycles of transducer of arm processor are the continuous ultrasound ripple signal 18 of TA; Make the ultrasonic pulse circuit produce the ultrasound wave of high pressure driving pulse and adjustable repetitive frequency; This pulse is added on the ultrasonic transducer 1, and making ultrasonic transducer 1 send frequency is 2.5～10MHz ultrasound wave.Ultrasonic signal 18 carries out echo reflection after vertical prestressing reinforcing bar 19 is transmitted to 28 of stiff ends, after said ultrasonic transducer 1 received echoed signal 20, the signal output part of ultrasonic transducer 1 was sent to data buffer 8 with echoed signal 20 through programmable filter 5, programmable amplifier 6 and A/D converter 7; Said programmable filter 5 with interfering clutter, noise attentuation after, the output terminal of programmable filter 5 connects programmable amplifier 6, the signal that ultrasonic transducer 1 is received fully amplifies; Suppress the level propagation backward of noise and large-signal, limit noise; And can carry out automatically apart from gain compensation echoed signal 20, echoed signal 20 is amplified to essentially identical amplitude level several times, is validity and the stability that guarantees system signal; Arm processor 14 can carry out frequency control to programmable filter 5; Sequential control closed and opened to arm processor 14 also can to programmable amplifier 6, and programmable amplifier 6 outputs connect A/D converter 7, and its data sampling speed is 1Gsps; Carry out high speed acquisition through 7 pairs of echoed signals of A/D converter 20; And the signal that collects sent among the DSP 9 through data buffer 8, DSP 9 receives through the data behind the buffer memorys, accomplishes signal Processing; And with the signal storage that collects to RAM memory block 11; After sampling was accomplished, arm processor 14 read the data that are temporary in the RAM memory block 11, and exported the time point signal of counting to clock counter 10; The time point of counting is the time interval (being called for short: during sound) of two different ultrasonic reflection echoed signals, 10 accurate travel-times of measuring ultrasonic echo in time gate 21 of clock counter.Said arm processor 14 all is connected with storer 15, keyboard 16, display 17, programmable amplifier 6, programmable filter 5, RAM memory block 11 and temperature measurement circuit 12; The output terminal of said temperature measurement circuit 12 is connected with arm processor 14, and the input end of temperature measurement circuit 12 connects temperature sensor 13; Said temperature sensor 13 is magnetic right cylinder sensing elements, is used to gather the temperature value of vertical prestressing reinforcing bar 19; Said temperature sensor 13 is connected through temperature measurement circuit 12 with arm processor 14, and said arm processor 14 is used for the result of calculation of vertical prestressing reinforcing bar 19 is carried out the temperature correction.Said display 17 is used for showing in real time the ultrasonic scanning waveform, hyperacoustic the time, the stress state test result of vertical prestressing reinforcing bar; Said keyboard 16 is used for the external data input; Said storer 15 is used to store vertical prestressing reinforcing bar temperature effect coefficient, material influence coefficient, calibration formula and result of calculation.
The principle of the method for testing of the utility model is following:
The method of testing of this vertical prestressing reinforcing bar effective stress level; Ultrasonic transducer is adsorbed on the horizontal end face of vertical prestressing reinforced bar stretching end; After ultrasonic transducer was coupled by the vertical prestressing reinforcing bar through the ultrasound wave couplant, emission also received the ultrasound wave along vertical prestressing reinforcing bar transfers, based on the acoustic elasticity phenomenon of material; When the vertical prestressing reinforcing steel bar bear extends; Ultrasonic velocity through the vertical prestressing reinforcing bar has reduced, and the variation of stress has caused the variation of ultrasonic velocity, and temperature constant is t before and after the vertical prestressing reinforcing steel bar bear
0The time, the relation of the stress and the velocity of sound can be expressed as:
υ(σ，t
0)＝C
0(1-kσ) (1)
In the formula: υ (σ, t
0Hyperacoustic velocity of sound under the)-reference temperature, t
0-reference temperature, C
0Hyperacoustic velocity of sound when-reinforcing bar is unstressed, the constant coefficient that k-is relevant with the reinforcing bar material, the stress level of σ-vertical prestressing reinforcing bar.
Variation of temperature also can cause the variation of ultrasonic velocity, and when receiving stress and variation of temperature simultaneously with deformed bar, the interior velocity of sound of the effective stressed length range of reinforcing bar can be expressed as when perpendicular:
υ(σ，t)＝C
0(1-kσ)[1-m(t-t
0)] (2)
In the formula: υ (σ, t)-hyperacoustic velocity of sound when temperature is t, C
0Hyperacoustic velocity of sound when-reinforcing bar is unstressed, the constant coefficient that k-is relevant with the reinforcing bar material, the stress level of σ-vertical prestressing reinforcing bar, the m-temperature is to the influence coefficient of ultrasonic velocity, the actual temperature of t-vertical prestressing reinforcing bar, t
0-reference temperature.
And not can be expressed as by the velocity of sound υ (t) in the stress length range:
υ(t)＝C
0[1-m(t-t
0)] (3)
The effective stressed length L of reinforcing bar
eBe decided to be approximately: L
e=D
1+ D
2+ D
3+ D
4(4)
D in the formula
1The thickness of anchor plate on the-vertical prestressing reinforcing bar, D
2The thickness of anchor plate under the-vertical prestressing reinforcing bar, D
3Distance between the upper and lower anchor plate of-vertical prestressing reinforcing bar, D
4The external diameter of-vertical prestressing reinforcing bar.
After receiving temperature, stress in the effective stressed length range of reinforcing bar, length L
1(σ t) is:
L
1(σ，t)＝L
e+ΔL
s+ΔL
t (5)
ΔL
s＝L
e×σ/E (6)
ΔL
t＝L
e×α×(t-t
0) (7)
In the formula, L
eThe effective stressed length of-reinforcing bar, Δ L
sThe reinforcing bar elongation that-stress causes, Δ L
tThe reinforcing bar elongation that temperature causes in-effective stressed length, the stress level of σ-vertical prestressing reinforcing bar, the elastic modulus of E-reinforcing bar, the expansion coefficient of α-reinforcing bar material, the actual temperature of t-vertical prestressing reinforcing bar, t
0-reference temperature.
Do not receive in the stress length range, reinforcing bar length only is acted upon by temperature changes, length L
2(t) be:
L
2(t)＝(L-L
e)[1+α×(t-t
0)] (8)
In the formula: L is the length overall of reinforcing bar, L
eThe effective stressed length of-reinforcing bar, the expansion coefficient of α-reinforcing bar material, the actual temperature of t-vertical prestressing reinforcing bar, t
0-reference temperature.
Hyperacoustic velocity of sound is to be difficult for directly being measured, can be through the time and variable quantity from ultrasonic acoustic, calculate the stress of vertical prestressing reinforcing bar.The vertical prestressing reinforcing bar is t in temperature, during the sound when stress is σ under S and the reference temperature reinforcing bar not under the stressing conditions the time S
0It is poor to do:
Bringing formula (2)～(8) into formula (9) can get:
Analyze for simplifying, consider that at first reinforcing steel bar bear front and back temperature constant is t=t
0The time, the changes delta S during sound.Can avoid because temperature variation causes the flexible influence to sound transit-time measurement of reinforcing bar, and k σ＜＜1, by formula (10), can get:
Can (11) be expressed as
ΔS＝S-S
0＝A?L
eσ (12)，
As t ≠ t
0The time, consider that the vertical prestressing reinforcing bar is σ=0 o'clock not receiving stress, the reinforcing bar temperature variation with the time changes delta S between relation.Can avoid because STRESS VARIATION causes the flexible influence to sound transit-time measurement of reinforcing bar, and m ≈ 10
-4, m (t-t
0)＜＜1 by formula (10), can get:
Can (13) be expressed as
ΔS＝S-S
0＝B×L×(t-t
o) (14)
Recruitment during ultrasonic acoustic be when sound recruitment that stress causes cause with temperature sound the time recruitment sum, vertical prestressing reinforcing steel bar bear front and back temperature is respectively t
1, t
2The time the ultrasonic acoustic duration all be transformed into the sound duration under the reference temperature, according to formula (12), (13), (14) can knowledge sound the time and the relation of stress can be expressed as:
[S
2-B×L(t
2-t
o)]-[S
1-B×L(t
1-t
o)]＝A?L
eσ (15)
The computing formula of the effective stress level of reinforcing bar can be expressed as:
According to above-mentioned principle, the concrete testing procedure of effective stress level that obtains the vertical prestressing reinforcing bar is following:
Step 1: get one section with actual bridge in the deformed bar of the identical material of vertical prestressing reinforcing bar as the deformed bar of demarcating usefulness; Be close to horizontal section at the stretch-draw end of the deformed bar of demarcating usefulness ultrasonic transducer is installed, said ultrasonic transducer is connected with programmable filter with radiating circuit through lead; Simultaneously, the side absorption type mounting temperature sensor at the revealed section of the deformed bar of demarcating usefulness is connected through lead temperature sensor with temperature measurement circuit.
Step 2 is demarcated the sound time difference of vertical prestressing reinforcing bar and the relation curve of stress level; At reference temperature t
0Under the condition; Behind the many groups of the deformed bar stickup resistance strain gages of demarcating usefulness, keep the effective stressed length of initial reinforcing bar constant, the circulation of carrying out tension tester adds Unloading Calibration; Loading and unloading is demarcated power rank (the every 50kN of this demarcation power is a rank) to certain; (relation of strain of vertical prestressing reinforcing bar and stress is σ=ε * E to the stress of data and the vertical prestressing reinforcing bar that collected by resistance strain gage, wherein: σ-vertical prestressing reinforcing bar effective stress level, the strain of ε-vertical prestressing reinforcing bar when gathering the sound of vertical prestressing reinforcing bar effective stress horizontal checkout device; The elastic modulus of E-reinforcing bar) repeatedly, and average; Obtain preliminary calibration formula by calibration result: Δ S=K
sσ, wherein: poor when a certain stress of Δ S-vertical prestressing reinforcing bar and original state (load before) hyperacoustic, K
s-Stress Constants, σ-vertical prestressing reinforcing bar effective stress level.Obtain the sound time difference of vertical prestressing reinforcing bar and the relation curve of stress level.
Referring to shown in Figure 2, the utility model vertical prestressing reinforcing bar effective stress level and the relation curve of the sound time difference.The horizontal σ of vertical prestressing reinforcing bar effective stress (MPa) among the figure is the stress value of the reinforcing bar that obtained by resistance strain gage under the stretching control force, and sound time difference Δ S (ns) is poor when a certain stress of vertical prestressing reinforcing bar and original state (loading preceding) hyperacoustic just.The formula that the match of stretching force nominal data obtains is: Δ S=3.0684 σ.
Referring to shown in Figure 3, the effective length L of the utility model vertical prestressing reinforcing bar
eSize agreement figure, the D among the figure
1Be the thickness of anchor plate on the vertical prestressing reinforcing bar, D
2Be the thickness of anchor plate under the vertical prestressing reinforcing bar, D
3Be the distance between the upper and lower anchor plate of vertical prestressing reinforcing bar, D
4External diameter for the vertical prestressing reinforcing bar.
Step 3, the material influence coefficient of demarcation vertical prestressing reinforcing bar, L in the present embodiment
e=0.907m is according to from storer, extracting material influence coefficient formula Δ S=A * L
e* σ again according to the calibration result Δ S=3.0684 σ of step 2, can get the material coefficient A=3.383 (nsm of vertical prestressing reinforcing bar
-1Mpa
-1), and the material influence coefficient deposited in the storer.
Step 4 is demarcated the sound time difference of vertical prestressing reinforcing bar and the relation curve of temperature variation; Under the not stressed state of deformed bar; The vertical prestressing reinforcing bar is heated and the control of lowering the temperature with Temperature-controlled appliance, each temperature control hierarchy (per 5 ℃ is a temperature rank), data when deformed bar liter (falling) the temperature back hyperacoustic of usefulness is demarcated in the several times collection; Several times measure the real time temperature data on the deformed bar surface of demarcating usefulness, and average; Obtain preliminary calibration formula by calibration result: Δ S=K
t(t-t
o), wherein: poor under a certain state of temperature of Δ S-vertical prestressing reinforcing bar and the reference temperature hyperacoustic the time, wherein: the real time temperature of t-vertical prestressing reinforcing bar, t
0-reference temperature, poor under a certain state of temperature of Δ S-vertical prestressing reinforcing bar and the reference temperature hyperacoustic the time, K
t-thermal constant; Obtain the sound time difference of vertical prestressing reinforcing bar and the relation curve of temperature variation.
Referring to shown in Figure 4, the utility model vertical prestressing reinforcing bar temperature variation and the relation curve of the sound time difference.Δ t=(t-t among the figure
o) be the real time temperature of reinforcing bar and the difference of reference temperature (℃), sound time difference Δ S (ns) is poor hyperacoustic the time under a certain state of temperature of vertical prestressing reinforcing bar and the reference temperature just.The formula that the temperature calibration data fitting obtains is: Δ S=29.465 Δ t.
Step 5, the temperature effect coefficient of demarcation vertical prestressing reinforcing bar extracts temperature effect coefficient formula Δ S=B * L * (t-t from storer
o), and the calibration result Δ S=K of step 4
t(t-t
o), obtain the temperature coefficient B of vertical prestressing reinforcing bar, and temperature coefficient is deposited in the storer;
T in the present embodiment
o=23 ℃, the length overall L=1.097m of the vertical prestressing reinforcing bar of demarcation usefulness is according to formula (14) Δ S=B * L * (t-t
o), according to the calibration result Δ S=32.323 Δ t of step 4, can get the temperature coefficient B=29.465 (nsm of vertical prestressing reinforcing bar
-1℃
-1)
Obtain the computing formula of vertical prestressing reinforcing bar effective stress level by above calibrating parameters:
Step 6; After the computing formula of vertical prestressing reinforcing bar effective stress level; Vertical prestressing reinforcing bar effective stress horizontal checkout device is installed on the vertical prestressing reinforcing bar in the actual bridge; Be close to horizontal section at the stretch-draw end of vertical prestressing reinforcing bar ultrasonic transducer is installed, said ultrasonic transducer is connected with programmable filter with radiating circuit through lead; Simultaneously, at the side absorption type mounting temperature sensor of the revealed section of vertical prestressing reinforcing bar, temperature sensor is connected with temperature measurement circuit through lead; Before stretch-draw, S when not testing hyperacoustic under the stress
1Temperature t with reinforcing bar
1, calculate the effective stressed length L of reinforcing bar length L and reinforcing bar according to the mark on the drawing
e
Referring to shown in Figure 5; The test synoptic diagram of the utility model vertical prestressing reinforcing bar is installed in vertical prestressing reinforcing bar effective stress horizontal checkout device on the vertical prestressing reinforcing bar in the actual bridge; Be close to horizontal section at the stretch-draw end of vertical prestressing reinforcing bar ultrasonic transducer is installed, said ultrasonic transducer is connected with programmable filter with radiating circuit through lead; Simultaneously, at the side absorption type mounting temperature sensor of the revealed section of vertical prestressing reinforcing bar, temperature sensor is connected with temperature measurement circuit through lead; Before the vertical prestressing reinforced bar stretching, test original state, obtain the computing formula of vertical prestressing reinforcing bar effective stress level by above-mentioned calibrating parameters:
S
1Before-the reinforced bar stretching hyperacoustic the time, S
2Behind-the reinforced bar stretching hyperacoustic the time, the length of L-reinforcing bar,
L
eThe effective stressed length of-reinforcing bar, t
1Temperature value before the-reinforced bar stretching, t
2Temperature value behind the-reinforcing steel bar bear.
Step 8, the effective stress level of calculating case beam vertical prestressing reinforcing bar; According to the calibration result of step 3 vertical prestressing reinforcing bar material influence coefficient and the calibration result of step 5 vertical prestressing reinforcing bar temperature effect coefficient, by the reinforcing bar length L that step 6, step 7 obtain, the effective stressed length L of reinforcing bar
e, S hyperacoustic the time before and after the reinforcing steel bar bear
1, S
2, the temperature value t before and after the reinforcing steel bar bear
1, t
2, calculate through arm processor, obtain the effective stress horizontal survey value of vertical prestressing reinforcing bar.
Specific embodiment is following: to step 7, the length overall L of the vertical prestressing reinforcing bar that process measures is 3.030m, the thickness D of last anchor plate according to step 1
1Thickness D with following anchor plate
2Be 0.020m, the distance B between the upper and lower anchor plate
3Be 2.657m, the D outer diameter of vertical prestressing reinforcing bar
4=32mm, the effective stressed length L of reinforcing bar
e=D
1+ D
2+ D
3+ D
4=2.729m; Sound duration before and after the vertical prestressing reinforcing bar that ultrasonic transducer collects loads is respectively S
1=508559ns, S
2Temperature value before and after the=513927ns, vertical prestressing reinforcing steel bar bear is respectively t
1=25 ℃, t
2=28 ℃; Calculate through arm processor; The effective stress level that the formula that utilizes step 6 to obtain calculates the vertical prestressing reinforcing bar is 610.454MPa; And the design stretching force control of vertical prestressing reinforcing bar is 60 tons, and the stress of the vertical prestressing reinforcing bar that is collected by resistance strain gage is 588.436MPa, and the stress measurement error is superior to 5%.
The above embodiment; Be merely the more representational embodiment of the utility model; But the utility model institute resist technology scheme is not limited thereto; Any technician who is familiar with the present technique field can should be encompassed within the protection domain of the utility model from the direct all changes or the replacement of deriving or expecting easily of the disclosed content of the utility model in the technical scope that the utility model discloses.
Claims (4)
1. a vertical prestressing reinforcing bar effective stress horizontal checkout device is characterized in that: comprise ultrasonic transducer (1), ultrasonic pulse generator (2), booster circuit (3), radiating circuit (4), programmable filter (5), programmable amplifier (6), A/D converter (7), data buffer (8), DSP (9), clock counter (10), RAM memory block (11), temperature measurement circuit (12), temperature sensor (13), arm processor (14), storer (15), keyboard (16) and display (17);
Said ultrasonic transducer (1) is adsorbed on the horizontal section of vertical prestressing reinforcing bar (19) stretch-draw end (27), and said temperature sensor (13) is adsorbed on the side of the revealed section of vertical prestressing reinforcing bar (19);
The signal output part of said arm processor (14) connects the signal input part of ultrasonic pulse generator, and the pulse signal that ultrasonic pulse generator (2) sends is sent to the signal input part of ultrasonic transducer (1) through booster circuit (3) and radiating circuit (4); The signal output part of said ultrasonic transducer (1) is sent to data buffer (8) with ultrasound wave through programmable filter (5), programmable amplifier (6) and A/D converter (7); Said data buffer (8) is sent into the signal that collects among the DSP (9), said DSP (9) with the signal storage that collects to RAM memory block (11); Said arm processor (14) all is connected with storer (15), keyboard (16), display (17), programmable amplifier (6), programmable filter (5), RAM memory block (11) and temperature measurement circuit (12); The output terminal of said temperature measurement circuit (12) is connected with arm processor (14), and the input end of temperature measurement circuit (12) connects temperature sensor (13);
Said display (17) is used for showing in real time the ultrasonic scanning waveform, hyperacoustic the time, the stress state test result of vertical prestressing reinforcing bar;
Said keyboard (16) is used for the external data input;
Said storer (15) is used to store vertical prestressing reinforcing bar temperature effect coefficient, material influence coefficient, calibration formula and result of calculation.
2. vertical prestressing reinforcing bar effective stress horizontal checkout device according to claim 1; It is characterized in that: said ultrasonic transducer (1) is used to transmit and receive 1 to 20 periodically ultrasonic signal; Said ultrasonic transducer (1) is a piezoceramic transducer, and the outerwrap layer is a magnetic material.
3. vertical prestressing reinforcing bar effective stress horizontal checkout device according to claim 1, it is characterized in that: said temperature sensor (13) is magnetic right cylinder sensing element, is used to gather the temperature value of vertical prestressing reinforcing bar; Said temperature sensor (13) is connected through temperature measurement circuit (12) with arm processor (14), and said arm processor (14) is used for the result of calculation of vertical prestressing reinforcing bar is carried out the temperature correction.
4. vertical prestressing reinforcing bar effective stress horizontal checkout device according to claim 1; It is characterized in that: said arm processor (14) is used for the frequency control of closing and opening time sequence control and programmable filter (5) of programmable amplifier (6), and the data sampling speed of said A/D converter (7) is 1Gsps.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220149927 CN202599578U (en) | 2012-04-10 | 2012-04-10 | Device for measuring effective stress level of vertical prestressed reinforcing steel bar |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220149927 CN202599578U (en) | 2012-04-10 | 2012-04-10 | Device for measuring effective stress level of vertical prestressed reinforcing steel bar |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN202599578U true CN202599578U (en) | 2012-12-12 |
Family
ID=47317107
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201220149927 Expired - Fee Related CN202599578U (en) | 2012-04-10 | 2012-04-10 | Device for measuring effective stress level of vertical prestressed reinforcing steel bar |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN202599578U (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102636307A (en) * | 2012-04-10 | 2012-08-15 | 交通运输部公路科学研究所 | Effective stress level test device and method of vertical prestressed reinforcement |
| TWI477753B (en) * | 2013-01-18 | 2015-03-21 | China Steel Corp | Very low impact testing mechanism |
| CN107110732A (en) * | 2015-01-09 | 2017-08-29 | 罗伯特·博世有限公司 | For the vibration reception device for the vibration for receiving the component for causing vibration |
| CN107290091A (en) * | 2017-06-22 | 2017-10-24 | 广西大学 | A kind of tensioning force measuring system and its measuring method for prestress wire |
| CN110132349A (en) * | 2019-05-06 | 2019-08-16 | 山东大学 | The system and method for prestressed concrete beam temperature gradient identification effective prestress |
| CN110530571A (en) * | 2019-08-30 | 2019-12-03 | 航天精工股份有限公司 | The method that a kind of pair of belt sensor threaded male fastener carries out pretightning force calibration |
| CN113237582A (en) * | 2021-04-12 | 2021-08-10 | 机械工业第九设计研究院有限公司 | Wall internal stress detection method and detection system for engineering acceptance |
-
2012
- 2012-04-10 CN CN 201220149927 patent/CN202599578U/en not_active Expired - Fee Related
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102636307A (en) * | 2012-04-10 | 2012-08-15 | 交通运输部公路科学研究所 | Effective stress level test device and method of vertical prestressed reinforcement |
| TWI477753B (en) * | 2013-01-18 | 2015-03-21 | China Steel Corp | Very low impact testing mechanism |
| CN107110732A (en) * | 2015-01-09 | 2017-08-29 | 罗伯特·博世有限公司 | For the vibration reception device for the vibration for receiving the component for causing vibration |
| CN107110732B (en) * | 2015-01-09 | 2020-11-10 | 罗伯特·博世有限公司 | Vibration receiving device for receiving vibrations of a vibration-causing component |
| CN107290091A (en) * | 2017-06-22 | 2017-10-24 | 广西大学 | A kind of tensioning force measuring system and its measuring method for prestress wire |
| CN107290091B (en) * | 2017-06-22 | 2023-06-02 | 广西大学 | Tension force measurement system and method for prestressed steel strand |
| CN110132349A (en) * | 2019-05-06 | 2019-08-16 | 山东大学 | The system and method for prestressed concrete beam temperature gradient identification effective prestress |
| CN110132349B (en) * | 2019-05-06 | 2021-11-23 | 山东大学 | System and method for identifying effective prestress of prestressed concrete beam through temperature gradient |
| CN110530571A (en) * | 2019-08-30 | 2019-12-03 | 航天精工股份有限公司 | The method that a kind of pair of belt sensor threaded male fastener carries out pretightning force calibration |
| CN113237582A (en) * | 2021-04-12 | 2021-08-10 | 机械工业第九设计研究院有限公司 | Wall internal stress detection method and detection system for engineering acceptance |
| CN113237582B (en) * | 2021-04-12 | 2022-11-11 | 机械工业第九设计研究院股份有限公司 | Wall internal stress detection method and detection system for engineering acceptance |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102636307B (en) | Effective stress level test method of vertical prestressed reinforcement | |
| CN202599578U (en) | Device for measuring effective stress level of vertical prestressed reinforcing steel bar | |
| Chaki et al. | Guided ultrasonic waves for non-destructive monitoring of the stress levels in prestressed steel strands | |
| CN102818852B (en) | Test method and system for grouting compactness of pre-stressed duct of bridge | |
| Chaki et al. | Stress level measurement in prestressed steel strands using acoustoelastic effect | |
| US7614303B2 (en) | Device for measuring bulk stress via insonification and method of use therefor | |
| CN100416269C (en) | Non destructive detection mothod used for anchor rod anchored system | |
| CN102507743B (en) | Nondestructive testing method of bridge prestressed duct grouting compactness | |
| CN2226289Y (en) | Ultrasonic measurer for axial fastening stress of bolt | |
| CN106840477B (en) | Device and method for monitoring pre-stress loss of PSC structure for long time | |
| CN107505399A (en) | A kind of intelligent reinforced bar sleeve grouting defect inspection method based on vocal print feature | |
| Sun et al. | Application of low-profile piezoceramic transducers for health monitoring of concrete structures | |
| US9176108B2 (en) | Method and device for measuring corrosion metal loss | |
| Lei et al. | An automatic extraction algorithm for measurement of installed rock bolt length based on stress wave reflection | |
| CN108917998A (en) | A kind of monitoring method and system using ultrasonic echo monitoring surrouding rock stress state | |
| CN112683425A (en) | Method for detecting effective stress of longitudinal prestressed tendon in bridge body | |
| Kim et al. | Effect of prestress force on longitudinal vibration of bonded tendons embedded in a nuclear containment | |
| CN111855027A (en) | Stress monitoring method for bridge deck and newly-built bearing platform in bridge structure | |
| CN202710517U (en) | Ultrasound monitoring sensor for corrosion of reinforcement in concrete | |
| WO2011132024A1 (en) | Embedded material testing device and method | |
| CN110197015B (en) | Dam foundation pre-stressed anchor cable effective tensile stress measuring method | |
| Han et al. | Evaluation of rock bolt integrity using guided ultrasonic waves | |
| JP2001074706A (en) | Method for diagnosing ground anchor | |
| Kleitsa et al. | Assessment of metal strand wire pre-stress in anchor head by ultrasonics | |
| Bayane et al. | Acoustic emission and ultrasonic testing for fatigue damage detection in a RC bridge deck slab |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C53 | Correction of patent for invention or patent application | ||
| CB03 | Change of inventor or designer information |
Inventor after: Fu Yufang Inventor after: Zhang Jinquan Inventor after: Zhang Kechao Inventor after: Li Wanheng Inventor after: Zheng Yi Inventor before: Zhang Jinquan Inventor before: Fu Yufang Inventor before: Zhang Kechao Inventor before: Li Wanheng Inventor before: Zheng Yi |
|
| COR | Change of bibliographic data |
Free format text: CORRECT: INVENTOR; FROM: ZHANG JINQUAN FU YUFANG ZHANG KECHAO LI WANHENG ZHENG YI TO: FU YUFANG ZHANG JINQUAN ZHANG KECHAO LI WANHENG ZHENG YI |
|
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20121212 Termination date: 20180410 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |