Decree No. 69 / 2004 Coll.
Order setting out the requirements for tensioning sets for pretension concrete
Valid
Effective from 01.03.2004
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69
DECLARATION
of 3 February 2004
laying down requirements for tensioning sets for pretension concrete
The Ministry of Industry and Trade provides pursuant to Section 27 of Act No. 505 / 1990 Coll., on Metrology, as amended by Act No. 119 / 2000 Coll. and Act No. 137 / 2002 Coll., ("the Act") for the implementation of Sections 6 (2) and 9 (1) of the Act:
This Decree sets out the requirements for tensioning sets for pretension concrete (hereinafter referred to as "tensioning sets'), the type approval procedure and the verification procedure.
For the purposes of this Decree, the following sets shall be considered as tension sets:
(a) prestressed concrete structures; and
(b) ground anchors.
The terminology, the requirements for tensioning sets and their type-approval and verification are set out in the Annex.
This Decree shall take effect on 1 March 2004.
Minister:
Ing. Urban v. r.
Annex to Decree No 69 / 2004 Coll.
1 TERMINOLOGY
1.1. The tensioning kit is a device used to pre-press construction structures.
1.2. The tensioning press is a hydraulic cylinder with a piston, which serves to draw the pre-tensioning force.
1.3. Hydraulic aggregate is a device that serves as a source of pressure fluid for the tensioning press.
1.4. The force measuring device is the part of the tension set which is used to measure the size of the tension force.
1.5. The pressure gauge (deformation or electromechanical) is the part of the tensioning assembly that serves to measure the oil pressure in the tension press.
1.6. The measuring device of the piston shift is the part of the tensioning set which is used to measure the mutual displacement of the piston and cylinder, respectively the moving part of the tensioning set or the reinforcement against the anchor block.
1.7. An etalon load gauge is a load gauge (the third-order reference etalon of force) used for calibration and verification of tensioning sets.
1.8. Etalon pressure gauge is a pressure gauge used to calibrate pressure meters.
1.9. Etalon length gauge is an etalon that serves to calibrate the displacement measuring device.
1.10. Strength on scale Fi is the value of the force shown by the force measuring device.
1.11. The actual force, F is the value of the force determined by the ethalon force meter.
1.12. Effective area of the plunger, Su is the value of the area of the plunger of the tension press given by its geometric parameters.
1.13. Slide the loading press plunger, Lp is the value of the slide of the loading press piston measured between the piston and the cylinder.
1.14. Relative error of measuring device force, q is the difference of arithmetic averages of force read on scale and actual force, one of the forces being constant.
1.15. The conversion diagram is a diagram of the force dependence on the spring or anchor on the pressure of the oil in the cylinder of the tension press.
1.16. Sensitivity coefficient S is the ratio between the nominal force selected by the tensioner and the manometer reading during calibration.
1.17. The nominal force of the tensioning assembly is the force at which the gauge has nominal pressure.
1.18. The values read on the manometer scale X1, X2, X3, are the values read at 1st, 2nd and 3rd series of measurements in MPa.
1.19. The mean value of the tensioning set data at the unchanged position of the load cell Xs is the mean value calculated from the values at the 1st and 2nd series of measurements in MPa.
1.20. The mean value of the data of the Xst tensioning set at the modified position of the etalon load gauge is calculated as the arithmetic mean of the three series of measurements in MPa.
1.21. The relative deviation of b 'repeatability is the relative value determined as the difference between the tensioning set data at 1st and 2nd rows of measurements divided by the mean value at the unaltered position, to be reported in%.
1.22. The relative deviation of reproducibility b is determined as a proportion of the difference in values observed at 1st and 3rd series of measurements divided by the mean value when changing the position of the etalon load gauge, to be given in%.
1.23. The value of the tensioning set after relief of the tensioning set If, is given in MPa.
1.24. The value of the tensioning set before loading of the tension set Io is given in MPa.
1.25. The mean value of the tensioning set data at the rated force Xstj, to be given in%.
1.26. The relative deviation of the interpolation fa shall be determined as the proportion of the difference between the mean value at the change of position and the theoretical value calculated from the equation 1.order, to be given in%.
1.27. The theoretical value of Xa of the tensioning set shall be determined by the method of the smallest squares of the measured values.
1.28. The distinguishing capability r of the tensioning set scale is equal to 1 piece that can be estimated on the scale (for analogue scale) or a change of one unit (for number scale).
1.29. Relative standard wb repeatability uncertainty at unaltered load gauge position, to be reported in%.
1.30. Relative standard reproducibility uncertainty at wb position change, to be reported in%
1.31. Relative standard uncertainty of zero value wo, to be reported in%.
1.32. Relative standard interpolation uncertainty wa, to be reported in%.
1.33. Relative standard uncertainty of distinguishing capabilities wr, to be reported in%.
1.34. Relative standard uncertainty of the wEp calibration manometer is given in%.
1.35. Relative standard uncertainty of the wPp operating manometer, to be reported in%.
1.36. Relative standard uncertainty of the wF etalon load gauge, to be reported in%.
1.37. Relative extended uncertainty of the WF etalon load gauge, reported in%.
1.38. Relative standard uncertainty of the tension set w, to be reported in%.
1.39. Extended relative uncertainty of the tension set W, to be reported in%.
1.40. Profit K coefficient for probability p = 0,95%. According to EA-4 / 02 it is used k = 2.
2 REQUIREMENTS FOR COMPETENT DEVICES
2.1. METHOLOGICAL REQUIREMENTS
2.1.1. Requirements for the tensioner set
Divide the tensioners into classes according to Table 1. The accuracy class of the tension set is given by the accuracy class of the measuring device.
Table 1. Classes of accuracy of tensioning sets
| Třída | Relativní | Rozšířená nejistota kalibrační síly | |||
|---|---|---|---|---|---|
| chyba | odchylka reprodukovatelnosti | odchylka opakovatelnosti | odchylka interpolace | ||
| q | b | b´ | fa | Wbmc | |
| % | |||||
| 3 | 3 | 3 | 1,5 | 2 | 0,45 |
| 5 | 5 | 5 | 2,5 | 2,5 | 0,45 |
2.1.2. Requirements for calibration equipment
Calibration of the measuring system of the tension sets shall be carried out with an etalon load gauge. The pressure in the hydraulic system of the coupling assembly shall be measured by a reference or working manometer.
The following measurement instruments and equipment shall be used in the test:
(a) etalon load meters;
(b) reference pressure gauges;
(c) a tension frame,
(d) the length of etalon;
(e) thermometer.
2.1.2.1 Etalon load meters
A Class 1 or Class 2 ethalon load gauge shall be used for calibration of the tensioner force system.
Table 2. Allocation of etalon load meters for test machine class
| Třída napínací soupravy | Etalonový siloměr použitý ke kalibraci | |
|---|---|---|
| Třída etalonového siloměru | Největší hodnota rozšířené nejistoty kalibrace siloměru | |
| % | ||
| 3 | 1 | ± 0,24 |
| 5 | 1 nebo 2 | ± 0,45 |
2.1.2.2. Reference pressure gauge
The reference pressure gauge is used to calibrate the pressure meters used for measuring the pressure of the fluid in the cylinder of the tension press of the tensioner set. It can also be used for measuring the pressure in the cylinder of the tensioning set during its verification.
For the calibration of pressure gauges of Class 1 pre-tensioning sets, an etalon pressure gauges of Class 0,2 shall be used. For the verification of pressure gauges of Class 2.5, an etalon pressure gauge of at least Class 0.6 shall be used.
2.1.2.3 Tensioning frame
The tension frame is used to fasten the tension press to the load gauge and to introduce the test force. The tension frame shall comply with the technical conditions for the tensioning sets. It shall be sufficiently dimensioned to avoid influencing the measurement results during the test due to uneven frame deformation and to ensure that the force and deformation ratios during the test of the tensioning set are not too different from the conditions of the construction.
The frame includes other auxiliary devices which are used to handle the tension press and the etalon load meter and to fit them into the frame, the delimitation pads under the etalon load gauge and the ball pad.
The tension frame shall be so designed that it does not cause non-axis load of an etalon load gauge or otherwise does not distort the test results.
2.1.2.4. Etalon length gauge
The electronic means for testing and setting the measuring device of the tensioning press shall be selected according to the type of design and accuracy of the device. If a digital sliding scale is used as a measuring device, it may be used as an etalon of the length of the fourth accuracy class. If a specially designed displacement measuring device is used that does not allow the end-measure setting, the length etalon specified in the type test shall be used.
2.1.2.5. Thermometer
The thermometer is used to measure the temperature of the air in the test room, or where non-portable equipment is verified, and to measure the temperature of the etalon load meters.
2.2 TECHNICAL REQUIREMENTS
2.2.1 Tensioning set
The tension set consists of the following basic parts:
(a) the tension press,
(b) hydraulic aggregate; and
(c) connecting hoses.
2.2.1.1. Tensioning press
The tensioning press is used to select the force when pressurizing carrier cables for prestressed concrete structures and for pressurizing ground anchors. The cylinder of the tension press shall bear on the table the type of tension press, the business or the name and registered office of the legal person, if the manufacturer is the manufacturer, or the name, surname and permanent residence of the undertaking, and, where applicable, its business name, serial number, year of manufacture, nominal strength and nominal pressure.
2.2.1.2 Hydraulic aggregate
The hydraulic aggregate is used to supply pressure oil for the tensioning press and to measure the pressure in the hydraulic system. The type of hydraulic aggregate, the name or business name and registered office of the manufacturer, the production number, the year of manufacture, the nominal and maximum pressure, the quantity of liquid supplied, the electric motor power consumption and the supply voltage shall be indicated on the table.
All separate parts of the force measuring device and measuring device shall be marked with the name or business name of the manufacturer and the serial number, or the number of the coupling set, of the device.
2.2.1.3. Test frame load plates
The load plates are permanently installed in the test frame or are specific components thereof. The load plates shall be so manufactured as not to damage the seat surfaces of the etalon load gauge and the tensioning sets. One plate of an etalon load cell shall be fitted with a ball joint. The plates shall be so dimensioned as to avoid undesirable deformations of the etalon load gauge, which could adversely affect the measured values.
Plates are made of steel, the hardness of their surface must be greater than or equal to 55 HRC.
2.2.2. Labels and marks
2.2.2.1 Labels and marks on the tension set
The manufacturer's well-accessible identification table marked with:
(a) the trading firm or the name and registered office of the legal person, if the manufacturer is, or the name, surname and permanent residence of the trading natural person, or, where applicable, its trading company;
(b) the type of device;
(c) the year of manufacture;
(d) production numbers;
(e) nominal forces;
(f) the nominal pressure.
APPROVAL
3.1. Procedure for type approval
3.1.1. Requirements for the documentation submitted.
The applicant shall provide documentation in accordance with the specific legal regulation.1)
3.1.2. Samples
Since it is a costly device which is supplied in a small number of pieces, it is waived to deliver a special sample. Tests for type-approval shall be carried out on a tensioner set or the same type of tensioner set supplied by the manufacturer.
3.1.3. Requirements for test equipment
The test equipment referred to in paragraph 2.1.2 shall be used to perform the tests.
3.1.4 Environmental conditions
The normal conditions for the fitting of the tensioning assembly shall be ensured during the tests. The test temperature shall be (23 ± 5) ° C.
3.1.5 Allowed errors
Allowed errors are given in point 2.1.1.
3.1.6. Test procedure
The tests shall be carried out in accordance with paragraph 4.
3.2. Type-approval certificate
The particulars of the type-approval certificate shall be laid down in a separate legislative act (2).
4 VERIFICATION
4.1 The procedure for initial and subsequent verification is identical.
4.2 Verification of the tensioning assembly consists of:
(a) assessment of the design and technical condition of the tensioning assembly;
(b) checks on the correct operation;
(c) tests for the accuracy of the force measuring device;
(d) the accuracy tests of the measuring device;
(e) the issue of the document and the marking of the tether assembly by an official mark.
4.3 Assessment of design and technical condition of the tension set
4.3.1 Assessment of technical condition of the tensioning set
Assessment of the technical condition of the tensioning assembly means a visual inspection of the tensioning assembly. The condition of the original body of the tension press cylinder shall be checked for signs of damage and for damage to the seat surface, which is supported by a design or an etalon load gauge. If this area is worn too much, which could cause damage to the seating surface of the etalon load gauge or risk of affecting the accuracy of the measurement, the tension press shall be repaired.
4.3.2 Check of technical condition of the clamping device
When checking the technical condition of the clamping device, it shall be assessed whether the clamping of the pre-fastening element will be reliable to avoid slipping. This could result in non-axis load of the etalon load meter during the test, breaking the press plunger, which would affect the accuracy of the test force measurement. It would cause uneven loading of tension elements in operation.
4.3.3. Checking the technical state of the hydraulic aggregate
When checking the technical condition of the hydraulic aggregate, the condition and wear of the components shall be checked. The state of the pump shall be assessed and its ability to continuously achieve the prescribed parameters. The tightness of individual connections, the controllability of individual elements and the condition of connecting hoses is also assessed. Check that the kit complies with the conditions of safety of work and environmental requirements.
4.3.4 Visual inspection of the measuring device of the tension force
A visual inspection of the measuring device of the tension force and the measuring device of the piston position shall be carried out. It shall be checked that both measuring systems have the relevant requirements and meet the requirements for the relevant class.
4.3.5. Design control
The design design check of the coupling shall be carried out at each verification.
4.4 Description of individual tests
The test of the tension set shall consist of:
(a) tests of the force measuring device;
(b) test of the displacement measuring device.
4.4.1. Test conditions
The ambient temperature during the test of the coupling shall be within (23 ± 5) ° C. The test shall be carried out at a temperature not exceeding 2 ° C.
Before commencing the measurement of the customer's measuring instruments, it is necessary to ensure that the temperature of the used etalons and measuring instruments is balanced to the temperature of the environment in which the verification will take place for at least eight hours.
Before commencing the measurement, the environment is evaluated in terms of possible behavioural effects and the correct functioning of the equipment used:
(a) unacceptable vibration;
(b) intense heat sources;
(c) a strong source of disruptive energy;
(d) sufficient lighting, order and rest for work;
(e) sufficient space to permit practical and accurate movements and to reduce the risk of damage or danger;
(f) tampering with the measurement carried out by unauthorised persons;
(g) influencing the course and results of measurements and their evaluation by the customer.
If the customer does not ensure the availability of reference conditions, removal or avoidance of the effects mentioned, verification shall not be carried out.
4.4.2 Preparation for testing
It shall be established before the test whether:
a) the tensioning set has all the necessary requirements for its proper functioning;
(b) the tensioning assembly is capable of pre-loading in its entirety and complies with the technical requirements in its entirety;
(c) the temperature of the tensioning set and surrounding area allows reliable testing;
(d) the replacement parts of the measuring equipment and other parts which affect its metrological parameters belong to this tensioning assembly;
e) the etalon and measuring devices of force are functional and undamaged.
4.4.3 Test of the force measuring device
The test of the force measuring device shall be carried out with a certified class 1 or 2 load gauge. The time from the last calibration of the etalon load cell shall not exceed 24 months.
The test method, the type, class and nominal load of the etalon load gauge shall be chosen in such a way as to best match the design, strength range and accuracy class of the tensioning set. The tensioner set shall be clamped together with an etalon load-meter using a suitable pre-tensioning element into the test frame. It is necessary to ensure proper installation of the etalon load gauge between the test frame and the tensioning assembly in order to avoid damage to the seating surfaces of the etalon load gauge, tension press or frame.
The position of the tension set during the test depends on the design of the test frame. The tension set shall be tested at the vertical position of the tension press axis or at the horizontal position.
The tension set assembled in the load frame shall be loaded three times to the nominal value of the etalon load gauge or tension set (whichever is smaller) with a subsequent complete relief. The ethalon load gauge is set to the basic position, the pressure is measured by an electronic pressure gauge. Two series of subsequent complete relief shall be carried out. The load shall then be rotated by 90 °, the load shall be applied to the nominal force of the tension set followed by complete relief and the third series of measurements shall be carried out. Each series of measurements shall be carried out at 8 - 12 points of the scale of the tension set.
4.4.4 Test of piston position measuring device
The test of the coupling press position device shall be chosen according to the design and accuracy of the device. If a digital sliding scale is used as a measuring device, it shall be linked to the fourth-class end-points. If the measuring device is specially designed for the tensioning press and is part of it, there shall be points on the piston and cylinder of the tensioning press, between which the position of the plunger can be measured at its various displacement with a calibrated length gauge of the appropriate accuracy.
4.4.5 Evaluation of tests
The values measured during the test shall be recorded and evaluated. The arithmetic mean, the relative error of the force measuring device, the relative deviation of reproducibility, the relative deviation of repeatability and the relative deviation of interpolation shall be calculated.
4.4.5.1. Mean pressure in the tension press
The arithmetic mean is calculated from the measured values of the three series of pressure measurements according to the equation
X? = X1 + X2 + X33
where X1, X2, X3 are the measured oil pressure values in the cylinder of the tensioner set (MPa).
4.4.5.2. Mean value at unaltered load gauge position
Xo = X1 + X22,
| kde | X1 | 1. řada měření tlaku (MPa) |
| X2 | 2. řada měření tlaku (MPa) |
4.4.5.3 Sensitivity coefficient With tensioning sets is calculated according to the following equation
S = FNXN,
where FN is the nominal force of the tension set (kN)
XN mean of all measurement series (MPa)
4.4.5.4 Relative error of the force measuring device
The relative error of the force measurement device q in percent is calculated as the difference between the force values read on the Fi scale and the actual force F. The relative error of the force measuring device is determined only for tensioning sets where the force scale is given in units of force. For tensioning sets where a deformation pressure gauge with a scale specified in the pressure units is used, the determination of the relative error according to this paragraph shall not be made. The size of the relative error is given by the relationship
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Regulation Information
| Citation | Decree No. 69 / 2004 Coll., laying down requirements for tensioning sets for pretension concrete |
|---|---|
| Regulation Type | - |
| Author | - |
| Collection | Code of Laws |
| Date of Promulgation | 24.02.2004 |
|---|---|
| Effective from | 01.03.2004 |
| Effective until | - |
| Status | Valid |
The regulation text is for informational purposes only.
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