GOST 30062-93

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  ГОСТ 30062-93

GOST 30062−93 Reinforcement rod for concrete structures. Eddy current inspection method of strength characteristics

GOST 30062−93
Group Ж39

INTERSTATE STANDARD

REINFORCEMENT ROD FOR CONCRETE STRUCTURES
Eddy current inspection method of strength characteristics
Bar reinforcement for reinforced concrete structures. Eddy-current method of strength properties control

OKP 58 8000

Date of introduction 1995−01−01
Predislovie

1 DEVELOPED by the research Institute of building constructions (NIISK) and research, design and technological Institute of concrete and reinforced concrete (NIIZHB)

2 ACCEPTED by the Interstate scientific and technical Commission for standardization and technical regulation in construction (MNTKS) 10 November 1993

The adoption voted:

3 REPLACE GOST R 50594−93

4 ENTERED INTO force on 1 January 1995 as the state standard of the Russian Federation by the resolution of Gosstroy of Russia dated February 7, 1994 N 18−6

1 SCOPE

This standard applies to hot-rolled rod and thermomechanically strengthened reinforcing steel smooth and periodic profile diameters 6−40 mm, intended for reinforcement of concrete structures, and sets eddy current control method its strength characteristics (strength, physical or conditional yield strength).

This method is used for input control of reinforcing steel in the manufacture of precast and erection of precast concrete structures along with the GOST 12004, and if necessary, sorting of rebar for its strength characteristics.

2 Normative references

The present standard features references to the following standards:

GOST 8.326−89* GSI. Metrological certification of measuring instruments
________________
* On the territory of the Russian Federation the document is not valid. Apply the Procedure of testing standard specimens or means of measurement for the purposes of type approval, Administrative regulations on granting by Federal Agency on technical regulation and Metrology of the state service for the type approval of reference materials or type of measuring instruments, Requirements to the signs of type approval for standard samples or type of measuring instruments and their application, here and hereafter. — Note the manufacturer’s database.

GOST 5781−82 hot-rolled Steel for reinforcement of concrete structures. Specifications

GOST 10884−81* case hardening steels thermomechanical and thermally hardened periodic structure. Specifications
________________
* On the territory of the Russian Federation the document is not valid. Valid GOST 10884−94, here and hereafter. — Note the manufacturer’s database.

GOST 12004−81 Steel reinforcement. Methods of tensile tests.

3 Definitions

In this standard, the following terms apply;

3.1 ultimate strength  — the maximum stress, tensile strength prior to failure of the valves.

3.2 Physical yield strength  — tension the tension at which the reinforcing bar (sample) deforms without an appreciable increase in the effort.

3.3 yield strength  — the stress at which a conditionally instantaneous plastic deformation of the rebar reaches 0.2% of the estimated length of the strain gauge.

3.4 the dependence of the Calibration — set dependence (in the form of a table or graph of transfer) between an informative parameter and controlled strength characteristics of the valve.

3.5 Informative parameter — measured device parameter for which the dependence between this parameter and controlled strength characteristics of the valve.

4 Main provisions

4.1 Eddy current inspection method of strength characteristics of reinforcing steel (hereafter eddy current method) is based on the principle of changes in the parameters of eddy-current Converter caused by the introduction of the electromagnetic field of the valve stem.

4.2 Strength characteristics of reinforcing steel (ultimate strength, physical or conditional yield strength) is determined on the basis of experimentally established calibration dependencies between the informative parameters of eddy current method and controlled strength characteristics of the valve.

4.3 as informative parameters of eddy-current methods use amplitude, phase, frequency, time and other parameters of the eddy current signal Converter, which separately or in their combinations the dependence with controlled strength characteristics of reinforcing steel.

4.4 Calibration relationship between the measured informative parameters and controlled strength characteristics of rebar or methodology for determining this calibration based on taking the corresponding reinforcing steel and its diameters according to the user manual controls.

5 controls

5.1 To determine the strength characteristics of reinforcing steel used appliance WF-10ПР (specifications are given in Appendix A) or other means of control that meet the requirements of this standard.

5.2 Strength characteristics of the reinforcement is determined either directly on the readings (based on the calibration dependence is introduced into the device during its manufacture or introduced into it during the control), or by calculating the measured informative parameters and the established calibration relationships (4.4).

5.3 Selection of controls produced on the basis of the guide for their operation indicators:

a) the type and range of diameters controlled by the reinforcing steel;

b) minimum sample length or the maximum length of the rods controlled valves;

C) the range of the measured values of the strength characteristics of the reinforcement and errors of their determination (when measuring these characteristics directly in the readings);

d) the measured informative parameter eddy current method (4.3), the range of values of this parameter and its error determination and calibration of installed dependencies (4.4) to calculate the strength characteristics of the reinforcing steel at a controlled given informative parameter (for controls, which provide for the measurement of this informative parameter).

5.4 controls should provide for determination of strength properties of reinforcing steel of suitable type and diameter with a relative error no more than ±10%.

The value of the relative error control set experimentally for reinforcing steel appropriate, take over the manual controls.

5.5 controls allowed if they were certified in accordance with GOST 8.326, certified by the certificate on metrological certification.

5.6 In the operation of the controls require periodic verification, which is carried out in accordance with the instructions in the act of metrological certification of the means of control.

Calibration period between two successive verifications take on maintenance documentation means of verification.

After repairing the controls necessary to conduct extraordinary their calibration.

6 preparation for testing

6.1 In preparation for the implementation of controls based on the type and diameter of reinforcing steel a controlled and expected values of its strength characteristics, choose:

— the scale or display range of the used instrument — the measurement of the strength characteristics of the reinforcement directly on the readings;

— informative parameter and range of values — when calculating the strength characteristics of reinforcement according to the measured values of informative parameter and set the calibration dependencies.

6.2 the Scale of the device used is selected based on the conditions that the expected value of the measured indicators should be 20−80% of the maximum value of the selected scale of the instrument.

The scale of the measuring instrument or range of values of informative parameters indicated in the log control the strength characteristics of the valve.

6.3 Strength characteristics of reinforcing steel is controlled directly on the individual rods of length up to 13,5 m or on samples with a length of not less than 200 mm with a rough surface of the rebar.

The length of samples should be taken on the basis of the provision specified in the instruction manual for the controls of requirements that take into account the influence of boundary effect and diameter-controlled valves on the measurement results.

6.4 Selection of rods to control the strength characteristics of reinforcement produced from different bundles of reinforcing steel one of the party.

In the control samples should be selected from different cores taken from the different bundles of reinforcing steel one of the party.

6.5 In the input control, the number of the tested rods or samples from each lot of reinforcing steel must conform to established standards and technical specifications for this reinforcing steel and be not less than six.

6.6 in the control of reinforcing steel having no document about its quality or the performance of which does not correspond to that indicated in the document of quality, the number of the tested rods or samples should be doubled for comparison with specified in 6.5.

6.7 If necessary, sorting of reinforcing steel on the strength characteristics or the reinforcing steel of different strength classes, the number of the tested rods or samples must be at least 12 from each pack at least 6.

When sorting pre-stressed reinforcement number of tested rods or samples is recommended to increase to guarantee the strength characteristics of each rod.

6.8 Before carrying out control checks of the used device in accordance with the instruction manual.

7 control

7.1 Control of the strength characteristics of the reinforcement is carried out in the following sequence:

— test the core or sample is placed on a lining of dielectric material at a distance of 20−50 cm from the base and at least 1 m from other terminals;

— on the web (sample) includes measuring an eddy current transducer;

— between terminal (sample) and measuring eddy-current Converter is set corresponding to the diameter of the test fittings: dielectric bushings or spacers that provide alignment of the transducer relative to the longitudinal axis of the rod (specimen), uniform gap between them and their fixation;

— produce at least three measurements of the strength characteristics of rebar or informative parameter for each core (sample).

7.2 measurement Results are entered in the control log.

8 Rules for processing and presentation of inspection results

8.1 Mechanical characteristics of fittings when measuring directly on the testimony of the device is determined as the arithmetic mean value of three measurements of these characteristics for each core or sample.

In the measurement instrument informative parameter strength characteristics of reinforcement calculated by the arithmetic mean value of three measurements of this informative parameter for each core (sample) and the established calibration dependence of the informative parameter and controlled strength characteristics of the valve.

Strength characteristics of reinforcement determined on the basis of the nominal cross-sectional area of reinforcing steel.

Determination of strength characteristics are produced with an accuracy of 10 N/mm.

8.2 the Results of measurements of the strength characteristics of rebar or informative parameters, as well as the results of determining the strength characteristics of the valves or of their calculation according to the measured informative parameters and the established calibration dependencies are entered into the control log of the strength characteristics of the reinforcement (Appendix B).

8.3 Reinforcing steel on the strength characteristics consistent with the corresponding class, if the results of the control:

— the minimum value of the strength characteristics of each sample or core is not less rejection characteristics of reinforcing steel according to GOST 5781, GOST 10884 or specifications for reinforcing steel;

— with a smaller value of the strength characteristics of one or more samples (but not more than 10% of the rejection characteristics) under the conditions of:

;

,

where  — average value of the strength characteristics of reinforcing steel based on inspection results of all test samples (rods);

 — the absolute value of the relative error controls (5.4);

 — inspecting the value controlled by the strength characteristics of the reinforcing steel of suitable strength, mounted GOST 5781, GOST 10884 or specifications for this reinforcing steel;

 — the minimum value of the strength characteristics of each sample or core test results.

8.4 When you sort of rebar for strength or reinforcement steel of different classes part of the reinforcement can be assigned to appropriate strength or the appropriate strength class based on the minimum values of certain strength characteristics according to 8.3 the results of monitoring at least six cores (samples) from this part of the controlled valves.

8.5 results are unsatisfactory control at least one indicator on one rod or the sample or differences in the evaluation of testing results, the strength characteristics of the reinforcing steel should be determined by the methods specified in GOST 12004.

Annex a (informational). TECHNICAL CHARACTERISTICS OF THE INSTRUMENT VF-10ПР

APPENDIX A
(informational)

The device is designed to control the eddy current method of strength characteristics (temporary tear resistance, physical or conditional yield strength) core hot-rolled reinforcing steel strength classes A240 (A-I)-A1000 (A-VI) churchyard 5781 diameters 6−40 mm.

The device is made on the basis of microprocessor technology.

The results of the control of the strength characteristics of the valve are displayed on a digital display device. Also implemented the mode of determining the strength characteristics of reinforcement according to the measured informative parameters and keyboard input to the calibration dependencies.

The allowable value of the basic relative error in the control of strength characteristics of reinforcement of no more than 10%.

Hardware the time required for one measurement controlled by the strength characteristics of the reinforcement does not exceed 1 min.

The definition of instrument strength characteristics of thermomechanically strengthened reinforcing steel according to GOST 10884 produce when corrected according to the calibration between the measured informative parameters and controlled strength characteristics of reinforcing steel.

Overall dimensions of the device:

— functional unit — no more than 200х180х75 mm;

— eddy-current transducer — no more than 190х140х85 mm.

Unit weight — 5 kg (eddy-current transducer — no more than 2 kg).

The power — Autonomous from the six elements 343 or from an external power supply voltage of 9 V.

Developer and manufacturer of the device — NIISK of Mininistry of Ukraine (Kyiv).

ANNEX B (informational). The journal form to record the results of measurement of the strength characteristics of reinforcement

APPENDIX B
(informational)