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Engineering Construction Standard Full Text Information System
Construction Industry Standard of the People's Republic of China JG/T3057—1999
Straight thread splices with upset rebar ends
Straight thread splices with upset rebar ends
Published on April 26, 1999
Published by the Ministry of Construction of the People's Republic of China
Implemented on December 1, 1999
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JG/T3057-1999
Cited Standards
Definition and Symbols
Product Classification, Model and Marking
Technical Requirements
Test Methods
Inspection Rules||tt ||Marking, packaging, transportation and storage
Appendix A (Standard Appendix)
Appendix B (Suggestive Appendix)
Appendix C (Suggestive Appendix)
Loading system for joint performance inspection
Schematic diagram of joint classification according to use requirements.
Dimensions of upsetting head
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JG/T3057-1999
This product is a straight threaded steel bar joint formed by roughing the end of the steel bar and cutting it. This product standard is used in conjunction with the engineering technical standard 107-1996 "General Technical Regulations for Mechanical Connection of Steel Bars" (partially revised version 1998). Appendix A in the IGI
standard is the standard appendix, and Appendix B and Appendix C are suggestive appendices. This standard is proposed by the Standard and Quota Research Institute of the Ministry of Construction. This standard is managed by the China Academy of Building Research, the technical unit responsible for building engineering standards of the Ministry of Construction. The drafting units of this standard are: Building Structure Research Institute of China Academy of Building Research, Shanghai Iron and Steel Technology Research Institute, Beijing Architectural Design Institute, Construction Science Research Institute of the 12th Engineering Bureau of the Ministry of Water Resources and Electric Power, and the General Research Institute of Building Research of the Ministry of Metallurgy. The main drafters of this standard are: Liu Yongyi, Yu, Zhang Chengqi, Li Benduan, and Yang Xiongchuan. This standard is interpreted by China Academy of Building Research. bzsosO,co Engineering Construction Standard Full Text Information System
People's Republic of China Construction Industry Standard Straight Threaded Steel Bar Joints
Straight thread splices with upset rebar ends1
JG/T3057-1999
The standard specifies the product classification, technical requirements, test methods, inspection rules, and marking, packaging, transportation and storage of upset rebar ends.
This standard applies to forged straight threaded steel bar joints made of HRB335 (grade I steel) and HRB400 (grade III steel) hot-rolled ribbed steel bars. 2 Referenced standards
The clauses contained in the listed standards constitute the clauses of this standard through reference in this standard. When this standard is published, the versions shown are valid. All versions will be revised. Parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T197-1981 Ordinary thread tolerances and fits GB/T228—1987 Metal tensile test methods GB/T699-1988 High-quality carbon structural steel
GB1499-1998 Hot-rolled ribbed steel bars for reinforced concrete GB/T1591-1994 Low-alloy strength structural steel JGJ107—1996 General technical regulations for mechanical connection of steel bars (partial revision, 1998) 3 Definitions and symbols
This standard adopts the following definitions and symbols.
3.1 Terms
3.1.1 straight threads joints with upset rebar ends are joints made by upsetting the connecting end of the steel bar, processing the cylindrical thread and connecting it with a connecting sleeve. 3..2 rebar head with screw thread is the end of the steel bar processed into a cylindrical thread.
3.l.3 locking nut
a nut that locks the relative position of the sleeve and the screw head. 3.1.4 coupler
a connector with cylindrical thread used to connect steel bars. 3.2 Symbols
Main symbols
f—measured value of tensile strength of joint;
fa—measured value of tensile strength of steel bar;
fu——standard value of tensile strength of steel bar;
ultimate strain of tensile steel bar specimen; approved by the Ministry of Construction of the People's Republic of China on April 26, 1999 and implemented on December 1, 1999
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strain of steel bar under standard value of yield strength; u-——residual deformation of joint under uniaxial tension; u4u8u20——residual deformation of joint after repeated tension and compression for 4, 8, 20 times. Product classification, model and marking
Rebar joints are generally composed of thread heads and sleeves, and lock nuts are included when necessary. See Appendix B (suggested Appendix). 4.1 Product classification
See Table 1 for classification according to applicable steel bar strength level. Table 1 Classification of joints according to applicable steel bar grade
Applicable steel bar strength grade for joints
HRB335 (Grade I steel bar)
HRB400 (sub-grade steel bar)
Classification according to joint use requirements is shown in Table 2 and Appendix B. 4.1.2
Connectors are classified according to usage requirements
Standard type
Extended type
Expanded type
Reducing type
Positive and negative wire beater type
Locking nut type
Model and marking
Connecting steel bars under normal circumstances
Occasions of use
Used in situations where it is difficult to rotate the steel bars, connect the steel bars by rotating sleeves. Used in situations where it is difficult to align the steel bars
Used to connect steel bars of different diameters
Used in situations where the steel bars at both ends cannot rotate and the axial length needs to be adjusted. The steel bars cannot rotate at all, and the steel bars are connected by rotating sleeves, and the sleeves are locked with lock nuts. The model name code, characteristic code and main parameter code of the upsetting straight threaded steel bar joint are composed of. DZJ-
Main parameter code, using the steel bar strength level and steel bar nominal diameter to indicate the characteristic code, using the code in Table 2 to indicate
Name code, using DZT to indicate the marking example of straight threaded steel bar joint:
Example 1: Standard joint with steel bar nominal diameter of 32mm and steel bar strength level of HRB400 (III grade). Marked as DZJ·Ⅲ32JG/T3057-1999
Example 2: Reducing joint with steel bar nominal diameter of 36mm and 28mm and steel bar strength level of HRB335 (I grade). Marked as DZJ·YI36/28JG/T3057-19995Technical requirements
5.1 Performance requirements
5.1.1 The performance of forged straight threaded steel bar joints shall meet the requirements of both strength and deformation. The inspection indicators are shown in Table 3. bzsoso,om Characteristic code
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Unidirectional elongation
High stress repeated tension and compression
Large deformation repeated tension and compression
Table 3 Performance test index of upset straight threaded steel bar joint Strength
Ultimate strain
Residual deformation
Residual deformation
Residual deformation
f≥f% or f≥1. 15fk
e≥0. 04
u≤0.1mm
f≥f or fmt≥1.15fk
￥20≤0.3mm
fm≥f or 115ft
u≤0.3mm and ugb.6mm
5.1.2 When the upset straight threaded steel bar joint is used in the structure directly bearing dynamic load, it shall still have the fatigue resistance required by the design. 5.2 Usage requirements
5.2.1 Thread head
Under different working conditions, the thread head should meet the following usage requirements: aP The thread head applicable to standard joints should be 1/2 the length of the sleeve, with a tolerance of +1P (P is the pitch to ensure that the sleeve is in the middle position of the joint
. bD The thread head applicable to extended joints should be longer than the sleeve length to meet the requirement of connecting the steel bars by rotating the sleeve. 5.2.2 Sleeve
Under different working conditions, the sleeve should meet the following usage requirements: a) Standard sleeves should be convenient for connecting steel bars under normal conditions; b) Variable diameter sleeves should meet the connection requirements of steel bars of different diameters; cP Expanded sleeves should meet the working conditions where it is difficult to center the steel bars, and be convenient for buckle connection. 5.3 Material requirements
5.3.1 The requirements of the current national standard GB1499 should be met for thick steel bars. 5.3.2 The sleeve and lock nut should be made of high-quality carbon structural steel or alloy structural steel. There should be a quality assurance certificate from the supplier. 5.4 Manufacturing process requirements
5.4.1 Thread head
a) When cutting steel bars, the cut end face should be perpendicular to the axis of the steel bar, and there should be no horseshoe shape or extrusion. If the end is not straight, it should be straightened before cutting. b) The base circle diameter d1 (see Appendix C) of the upsetting head should be larger than the outer diameter of the thread head, the length Lo should be larger than 1/2 of the sleeve length, and the slope of the transition section should be ≤<1:3.
c) The forged upsetting head should not have transverse surface cracks perpendicular to the axis of the steel bar. d) Unqualified upsetting heads should be cut off and re-upset, and the upsetting heads should not be upset twice. e) If hot upsetting steel bars are selected, the steel bar upsetting head processing should be carried out indoors. f) When processing the steel wire head, water-soluble cutting lubricant should be used. When the temperature is below 0℃, anti-freezing measures should be taken. Threading should not be performed without lubricating fluid.
g) The thread of the steel wire head should match the thread of the connecting sleeve, and the tolerance zone should comply with the requirements of GB/T197. 6f can be selected. 5.4.2 Sleeve
a) The tolerance zone of the internal thread of the sleeve should comply with GB/T197, and 6H can be selected. b) Surface anti-rust treatment should be performed.
c) The sleeve material, size, thread specification, tolerance zone and accuracy grade should comply with the requirements of the product design drawings. 5.5 Appearance quality requirements
5.5.1 Thread head
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a) The tooth shape is full, and the tooth top width exceeds 0.6mm. The cumulative length of the bald tooth part should not exceed one thread circumference. b) The external dimensions, including the thread diameter and the thread head length, should meet the product design requirements. 5.5.2 Sleeve
a) There shall be no cracks or other defects on the surface.
b) The overall dimensions including the diameter of the internal thread of the sleeve and the length of the sleeve shall meet the product design requirements. c) Plastic protective plugs shall be added to both ends of the sleeve.
5.53 Joint
a) When splicing the joint, tighten it with a pipe wrench, and the two thread heads shall be pressed against each other in the center of the sleeve. b) After the splicing is completed, no more than one complete thread shall be exposed at each end of the sleeve. The number of exposed threads of the extended joint is not limited, but there shall be obvious markings to check whether the length of the thread head entering the sleeve meets the requirements. Test method
6.1 The high stress repeated tension and compression and large deformation repeated tension and compression tests of the steel bar joint specimens shall be carried out using a testing machine with a hydraulic clamp and capable of automatically recording the entire stress and strain process; the loading system of the test shall meet the requirements of Appendix A (suggested Appendix). 6.2
The dimensions of the joint test piece for type inspection are shown in Figure 1 and shall comply with the requirements of Table 4. 000000000000
2000000000000
Figure 1 Dimensions of test piece
Table 4 Dimensions of joint test piece and deformation measurement gauge size/mm
Length of sleeve of joint plus the transition section length of upset steel bars at both endsMeasurement gauge for residual deformation of joint test piece
Measurement gauge for ultimate strain of joint test piece
Steel bar diameter
Only unidirectional tensile strength test is carried out on the joint test piece at the construction site, and the test is carried out in accordance with GB/T228. 7 Inspection rules
7.1 Inspection classification
Joint performance inspection is divided into type inspection and construction site inspection. Sleeve inspection is factory inspection, and thread head inspection is processing site inspection. 7.2 Type inspection of joints
7.2.1 Type inspection shall be carried out in the following cases: a) when the joint product needs to be identified and its performance level is determined; b) when the material, process and specification are changed; c) when the sleeve processing unit stops production for more than one year; d) when the quality supervision department makes special requirements. 7.2.2 The content and performance indicators of type inspection are shown in Table 3. Actual measurement
Nominal diameter
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7.2.3 For each type, level, specification, material and process of mechanical connection joints, the type inspection specimens shall not be less than 9, of which the unidirectional tensile specimens shall not be less than 3, the high stress repeated tension and compression specimens shall not be less than 3, and the large deformation repeated tension and compression specimens shall not be less than 3. At the same time, three steel bar specimens of the same batch and specification shall be taken for mechanical property test. 7.2.4 The loading system for type inspection shall be carried out in accordance with the provisions of Appendix A, and its qualified conditions are: a) Strength inspection: the measured value of each test piece shall meet the inspection index specified in Table 3; b) Inspection of limit strain and residual deformation: the measured average value of each group of test pieces shall meet the inspection index specified in Table 3. 7.2-5 Type inspection shall be carried out by a testing agency recognized by the national, provincial and ministerial competent authorities and shall issue a test report and assessment conclusion. 7. Construction site inspection of joints
7.3.1 The technology provider shall submit a valid type inspection report to the user. 7.3.2 Before the start of the steel bar connection project and during the construction process, each batch of incoming steel bars shall be subject to joint process tests, and the process tests shall meet the following requirements:
a) There shall be no less than 3 joint test pieces for each specification of steel bars; b) The steel bar parent material of the joint test pieces shall be subject to a tensile strength test: the tensile strength of the 3 joint test pieces shall not only meet the strength requirements of Table 3, but also be greater than or equal to 0.95 times the actual tensile strength f of the steel bar parent material. When calculating the actual tensile strength, the actual cross-sectional area of the steel bar shall be used. 7.3.3
On-site inspection shall be conducted on appearance quality inspection and unidirectional tensile strength test. On-site inspection of joints shall be conducted in acceptance batches. 7.3.4
Under the same construction conditions, joints of the same grade, type and specification using the same batch of materials shall be inspected and accepted in batches of 500, and 500 or more shall also be considered as an acceptance batch. 7.3.5 For each acceptance batch of joints, three specimens must be randomly selected from the engineering structure for unidirectional tensile strength test, and their performance level shall be determined according to the strength requirements in Table 3. When the unidirectional tensile test results of the three specimens all meet the strength requirements in Table 3, the acceptance batch is qualified. If the strength of one specimen is unqualified, six more specimens shall be taken for re-inspection. If one specimen still fails the test result during the re-inspection, the acceptance batch is unqualified.
One time.
When 10 acceptance batches are continuously inspected on site and all the unidirectional tensile specimens are qualified in one sampling, the number of acceptance batch joints can be expanded. 7.4 On-site inspection of thread head processing
7.4.1 Inspection items
The on-site inspection items, inspection methods and inspection requirements of thread head processing are shown in Table 5 and Figure 2. Table 5 Thread head quality inspection requirements
Inspection items
Appearance quality
Overall dimensions
Major thread diameter
Medium and minor thread diameters
Name of measuring tool
Caliper or special measuring tool
Gauge for smooth shaft
Through end thread ring gauge
Non-end thread ring gauge
Inspection requirements
The tooth shape is full, the crest width exceeds 0.6mm, and the cumulative length of the bald tooth part does not exceed one continuous circumference
The thread head length should meet the design requirements. The thread head length tolerance of the standard joint is +1P. The through end gauge should be able to pass The major diameter of the thread, and the stop gauge rule should not pass through the major diameter of the thread to be able to be smoothly screwed into the thread and reach the screwing length to allow the ring gauge to screw into the end thread part, and the screwing amount should not exceed 3P (P is the pitch).bzsoso,com Engineering Construction Standard Full-text Information System
Stop gauge ring gauge
Steel perch warp head
Through end thread ring gauge
Steel wire head quality inspection diagram
7.4.2 Batching, sampling method and result judgment a) The processing workers should visually check the processing quality of the wire heads one by one, and use the ring gauge to check every 10 wire heads, and reject the unqualified
wire heads.
bThe qualified thread heads after self-inspection shall be randomly sampled and inspected by the quality inspector. The steel thread heads produced in one work shift shall be regarded as one acceptance batch, and 10% shall be randomly sampled and the quality inspection of steel thread heads shall be carried out according to the method in Table 5; when the qualified rate is less than 95%, the sampling shall be doubled. If the qualified rate is still less than 95% in the re-inspection, all steel thread heads shall be inspected one by one, and the unqualified thread heads shall be cut off, and the threads shall be re-upset and processed. c) After the thread heads are qualified in the inspection, they shall be protected with plastic caps or connecting sleeves. 7.5
Factory inspection of sleeve
Inspection items
Inspection items, inspection methods and requirements are shown in Table 6 and Figure 3. Table 6 Quality inspection requirements for connecting sleeves
Inspection items
Appearance quality
Overall dimensions
Thread minor diameter
Thread middle diameter and major diameter
Name of measuring tool
Vernier caliper or special measuring tool
Smooth plug gauge
Through end thread plug gauge
Non-end thread plug gauge
Non-end thread plug gauge
Inspection requirements
No cracks or other defects visible to the naked eye
Length and outer diameter meet the design requirements
Through end gauge should be able to pass through the minor diameter of the thread, while the positive end gauge should not pass through the minor diameter of the thread. The plug gauge cannot pass through the screw-on length and can be smoothly screwed into both ends of the connecting sleeve and reach the screw-on length. Internal thread of sleeve, but partial screwing from both ends of the sleeve is allowed, and the screwing amount should not exceed 3P (P is the pitch)
Connection sleeve
Through end thread plug gauge
Figure 3 (Schematic diagram of sleeve quality inspection
7.5.2 Batching, sampling method and result judgment1) Take 500 pieces as one inspection batch, and 10% of each batch shall be randomly inspected; 2) If the inspection results meet the technical requirements of Table 6, they shall be judged as qualified, otherwise they shall be judged as unqualified; 3) The qualified rate of random inspection shall be greater than or equal to 95%; when the qualified rate of random inspection is less than 95%, double the number shall be taken for re-inspection. When the qualified rate after double sampling is greater than 95%, the batch shall be judged as qualified. If it is still less than 95%, the batch shall be inspected one by one, and only qualified ones can be used. 8 Marking, packaging, transportation and storage
8.1 Thread
8.1.1 After the steel wire head passes the inspection, it should be covered with a plastic protective cap as soon as possible, and should be neatly stacked according to specifications. 8.1.2 During the rainy season or long-term stacking, the thread head should be covered to prevent rust. 8.1.3 The thread head should be properly protected during transportation to avoid rain, contamination, and mechanical damage. .bzsoso,com Engineering Construction Standard Full Text Information System
8.2 Sleeve and lock nutbzxZ.net
8.2.1 The sleeve should be marked with the model and specification. After the product passes the inspection, the two ends of the sleeve should be fastened with plastic sealing plugs. 8.2.2 Packaging
The sleeve should be packed in boxes when leaving the factory, and the product name, model, specification and quantity, manufacturing date and production batch number, and manufacturer name should be marked on the outside of the box. The packaging box should be tied firmly with packaging tape. The product certificate must be attached to the packaging box. The content of the product certificate includes
a) model and specification
b) applicable steel bar type;
c) performance level of sleeve;
d) product batch number;
e) date of manufacture;
f) quality approval stamp;
g) factory name, address and telephone number.
8.2.3 Transportation and storage
The connecting sleeve and lock nut should be properly protected during transportation and storage to avoid rain, contamination, mechanical damage or loss. Va8
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Appendix A
(Appendix of the standard)
Loading system for joint performance inspection
The test method for joint type inspection should be carried out according to the loading system shown in Appendix A1 and Figures A1, A2 and A3. A1
Table A1 Loading system for joint type inspection
Test items
Uniaxial tension
High stress repeated tension and compression
Large deformation repeated tension and compression
Loading system
0→0.6f*-→0.02f*-→destruction
(0. 90fx*-0. 5fx)
(Repeated 20 times)
0-(28-→-0.5f)→(5ey-→-0.5f)→destruction (Repeated 4 times)
(Repeated 4 times)
181 is 28 After repeated loading 4 times, the strain value represented by the distance between the intersection of the parallel line of Ea.5 and the abscissa at the loading stress level of 0.5f and the reverse unloading stress level of -0.25f. 282 is the strain value represented by the distance between the intersection of the E.5 parallel line and the horizontal axis at the unloading stress level of 0.5f and the reverse loading stress level of -0.25f× after 4 repeated loadings of 2e*. 30g, 84 are the strain values obtained by the same method as 61, 02 after 4 repeated loadings of 5e*. Figure A3
A2 The field uniaxial tensile test of the joint can adopt a single loading system from zero to failure. bzsosO,coEngineering Construction Standard Full Text Information System
Figure B Standard Connector
Figure B3 Flared Connector
Figure B5 Positive and Negative Thread Connector
Appendix B
(Suggested Appendix)
Schematic Diagram of Connector Classification by Use Requirements
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Figure B2 Extended Connector
Figure B4 Reducer Connector
Figure B6 Locking Female Connector
.5 The strain value represented by the distance between the parallel lines and the intersection of the horizontal axis. 30g, 84 are the strain values obtained by the same method as 61, 02 after 5e* is repeatedly loaded 4 times. Figure A3
A2 The field unidirectional tensile test of the joint can adopt a single loading system from zero to failure. bzsosO,co Engineering Construction Standard Full Text Information System
Figure B Standard Joint
Figure B3 Flared Joint
Figure B5 Positive and Negative Threaded Joint
Appendix B
(Suggested Appendix)
Schematic diagram of joint classification according to use requirements
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Figure B2 Extended Joint
Figure B4 Reducer Joint
Figure B6 Locking Female Joint
.5 The strain value represented by the distance between the parallel lines and the intersection of the horizontal axis. 30g, 84 are the strain values obtained by the same method as 61, 02 after 5e* is repeatedly loaded 4 times. Figure A3
A2 The field unidirectional tensile test of the joint can adopt a single loading system from zero to failure. bzsosO,co Engineering Construction Standard Full Text Information System
Figure B Standard Joint
Figure B3 Flared Joint
Figure B5 Positive and Negative Threaded Joint
Appendix B
(Suggested Appendix)
Schematic diagram of joint classification according to use requirements
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Figure B2 Extended Joint
Figure B4 Reducer Joint
Figure B6 Locking Female Joint
.
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