GB 13788-2024 (GB13788-2024) & related versions
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Preview this PDF: GB 13788-2024
Preview this PDF: GB 13788-2024
GB 13788-2024
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 77.140.15
CCS H 44
Replacing GB/T 13788-2017
Cold Rolled Ribbed Steel Bars
ISSUED ON: JUNE 25, 2024
IMPLEMENTED ON: SEPTEMBER 25, 2024
Issued by: State Administration for Market Regulation;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative References ... 4
3 Terms and Definitions ... 4
4 Designation ... 5
5 Dimensions, Shape, Weight and Allowable Deviations ... 5
6 Raw Materials and Properties ... 10
7 Test Methods ... 11
8 Inspection Rules ... 13
9 Packaging, Marking and Quality Certificate ... 13
Appendix A (normative) Hot-rolled Wire Rods for Cold-rolled Ribbed Steel Bars ... 15
Cold Rolled Ribbed Steel Bars
1 Scope
This document specifies the designation, dimensions, shape, weight and allowable deviations,
raw materials and properties, test methods, inspection rules, packaging, marking and quality
certificate of cold rolled ribbed steel bars (hereinafter referred to as the steel bars).
This document is applicable to cold rolled ribbed steel bars for ordinary reinforced concrete,
manufacturing welded mesh and prestressing concrete.
2 Normative References
The contents of the following documents constitute indispensable clauses of this document
through the normative references in the text. In terms of references with a specified date, only
versions with a specified date are applicable to this document. In terms of references without a
specified date, the latest version (including all the modifications) is applicable to this document.
GB/T 222 Permissible Tolerances for Chemical Composition of Steel Products
GB/T 2101 General Requirement of Acceptance, Packaging, Marking and Certification for
Section Steel
GB/T 2103 General Requirements for Acceptance, Packaging, Marking and Quality
Certification of Steel Wire
GB/T 17505 Steel and Steel Products - General Technical Delivery Requirements
GB/T 21839 Test Methods of Steel for Prestressing Concrete
GB/T 28900 Test Methods of Steel for Reinforcement of Concrete
YB/T 081 Rule for Rounding off of Numerical Values and Judgement of Testing Values for
Technical Standards of Metallurgy
3 Terms and Definitions
The following terms and definitions are applicable to this document.
3.1 cold rolled ribbed steel bars
Steel bars with transverse ribs evenly distributed along the length direction on their surface after
hot-rolled round wire rods are subjected to cold rolling.
3.2 nominal diameter
The diameter of a circle equal to the nominal cross-sectional area of the steel bars.
3.3 specific projected rib area
The ratio of the projected area of a transverse rib on a plane perpendicular to the axis of the
steel bars to the product of the nominal perimeter of the steel bars and the rib spacing.
3.4 rib spacing
The chord length of the discontinuous part of the transverse rib on the circumference of the
steel bars projected on a plane perpendicular to the axis of the steel bars.
4 Designation
There are five designations for the steel bars: CRB550, CRB600H, CRB650, CRB800 and
CRB800H. CRB550 and CRB600H are steel bars for ordinary reinforced concrete, while
CRB650, CRB800 and CRB800H are steel bars for prestressing concrete.
C, R, B and H are respectively the first letters of the words “Cold rolled”, “Ribbed”, “Bars” and
“High ductility”; the figures represent the characteristic value of tensile strength.
5 Dimensions, Shape, Weight and Allowable Deviations
5.1 Nominal Diameter Ranges
The nominal diameter range of CRB550 steel bars is 4 mm ~ 12 mm, the nominal diameter
range of CRB600H steel bars is 4 mm ~ 16 mm, and the nominal diameters of CRB650 steel
bars and above are 4 mm, 5 mm and 6 mm.
5.2 Shape
5.2.1 Shape requirements
CRB600H shall have two-sided ribs (see Figure 1), CRB550 and CRB650 shall have three-
sided ribs (see Figure 2). Upon negotiation between the supply-side and the demand-side,
CRB800 and CRB800H are allowed to adopt other shapes.
5.2.2.4 The bevel angle on both sides of the transverse ribs of the steel bars with two-sided
ribs and three-sided ribs and the surface of the steel bars shall not be less than 45.
5.2.2.5 The sum of the transverse rib spacings of the steel bars with two-sided ribs and three-
sided ribs shall not be greater than 20% of the nominal circumference (fi 0.2d).
5.2.2.6 The specific projected rib area fr shall be determined in accordance with Formula (1):
Where,
K = 2 (two-sided ribs) or 3 (three-sided ribs);
FR---the longitudinal cross-sectional area of one rib, expressed in (mm2);
---the included angle between the transverse rib and the axis of the steel bar, expressed in ();
d---the nominal diameter of the steel bar, expressed in (mm);
l---the transverse rib interval, expressed in (mm).
If the geometric parameters of the steel bars are known, the specific projected rib area can be
calculated using Formula (2):
Where,
d---the nominal diameter of the steel bar, expressed in (mm);
fi---the sum of the spacings between each row of transverse ribs on the circumference of the
steel bar, expressed in (mm);
h---the midpoint height of the transverse rib, expressed in (mm);
h1/4---the height at 1/4 of the transverse rib, expressed in (mm);
l---the transverse rib interval, expressed in (mm).
NOTE: the calculation results of Formula (2) are approximate values.
5.3 Dimensions, Weight and Allowable Deviations
The dimensions, weight and allowable deviations of the steel bars with two-sided ribs and three-
sided ribs shall comply with the stipulations of Table 1.
supply-side and the supply-side, it is allowed to be replaced by the inspection data of the same
designation continuously produced with the same raw materials and the same process.
7.2 Mechanical Properties
The nominal cross-sectional areas listed in Table 1 are used to calculate the strength of the steel
bars.
7.3 Stress Relaxation Test
7.3.1 During the test, the ambient temperature of the specimen shall be maintained at 20 C
2 C.
7.3.2 Mechanical straightening is allowed on the specimen, but any heat treatment or other cold
machining shall not be carried out.
7.3.3 The initial test force applied onto the specimen is 70% of the nominal tensile strength of
the specimen multiplied by the nominal cross-sectional area of the specimen.
7.3.4 The loading speed is 200 MPa/min 50 MPa/min. The loading of the initial load shall be
completed within 3 ~ 5 minutes. After maintaining the load for 2 minutes, start recording the
relaxation value.
7.3.5 The length of the specimen is not less than 60 times the nominal diameter.
7.3.6 It is allowed to use test data of at least 120 h to extrapolate the 1,000-h relaxation rate
value.
7.4 Dimensional Measurements
7.4.1 The height of the transverse ribs is measured by measuring the height of each row of
transverse ribs of the same section and taking the average value; the rib interval is measured by
measuring the average interval, that is, measure the distance between the centers of the 1st and
11th transverse ribs in the same row and divide it by 10, which is the average interval between
the transverse ribs.
7.4.2 Dimensional measurements are accurate to 0.02 mm.
7.5 Measurement of Weight Deviations
When measuring the weight deviations of the steel bars, the length of the specimen shall not be
less than 500 mm. The length measurement is accurate to 1 mm and the weight measurement
is accurate to 1 g. The weight deviations (%) of the steel bars shall be calculated in accordance
with Formula (3):
Where,
---the deviation of the actual weight from the theoretical weight, expressed in (%);
M---the actual weight of the specimen, expressed in (g);
L---the length of the specimen, expressed in (mm);
m---the theoretical unit weight, expressed in (g/mm).
7.6 Rounding-off of Numerical Values
The rounding-off and determination of numerical values of the inspection results shall comply
with the stipulations of YB/T 081.
8 Inspection Rules
8.1 Inspection and Acceptance
The inspection and acceptance of the steel bars shall be carried out by the supply-side’s quality
supervision department. The demand-side has the right to conduct inspection.
8.2 Batch Grouping Rules
The steel bars shall be inspected and accepted in batches. Each batch shall be composed of steel
bars of the same designation, the same shape, the same specifications, the same production
process and the same delivery status. Each batch shall not be greater than 60 t.
8.3 Sampling Quantity
The sampling quantity for steel bar inspection shall comply with the provisions of Table 4.
8.4 Re-inspection and Determination
The re-inspection and determination of the steel bars shall comply with the provisions of GB/T
17505.
9 Packaging, Marking and Quality Certificate
9.1 Each plate (bundle) of steel bars shall be evenly tied with no less than 3 tracks, and the ends
shall be bent into the plate.
9.2 The steel bars shall be rolled with obvious and complete steel bar designation marks. The
interval of the marks is twice the interval of the transverse ribs. One transverse rib within the
mark interval shall be cancelled, as shown in Figure 3. For high ductility cold-rolled ribbed
steel bars, a short transverse rib shall be added within the 3rd mark interval, as shown in Figure
4. The steel bars are only allowed to be rolled with the factory name or factory logo, and shall
......
GB/T 13788-2017
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 77.140.60
H 44
Replacing GB/T 13788-2008
Cold rolled ribbed steel bars
ISSUED ON. JULY 12, 2017
IMPLEMENTED ON. APRIL 1, 2018
Issued by. General Administration of Quality Supervision, Inspection and
Quarantine of the PRC;
Standardization Administration of the PRC.
3. No action is required - Full-copy of this standard will be automatically &
immediately delivered to your EMAIL address in 0~60 minutes.
Table of Contents
Foreword ... 3
1 Scope .. 5
2 Normative references ... 5
3 Terms and definitions ... 5
4 Classification and designations ... 6
5 Size, shape, weight, and allowable deviation .. 6
6 Technical requirements ... 13
7 Test methods ... 15
8 Inspection rules .. 16
9 Packaging, marking, and quality certificate ... 17
Foreword
This Standard is drafted in accordance with the rules given in GB/T 1.1-2009.
This Standard replaces GB/T 13788-2008 “Cold rolled ribbed steel wires and
bars”. As compared with GB/T 13788-2008, the main technical changes of this
Standard are as follows.
- RIVISE relevant provisions on classification and codes;
- ADD the designations of high-elongation cold rolled ribbed steel bars.
CRB600H, CRB680H, and CRB800H;
- ADD the shape, size and mark diagram of four-sided ribbed steel bars;
- RIVISE relevant provisions on the designation and chemical composition;
- ADD the mechanical property requirement for high-elongation cold rolled
ribbed steel bars CRB600H, CRB680H, and CRB800H;
- RIVISE relevant provisions on percentage elongation after fracture,
percentage total elongation at maximum force (Agt) and tensile-to-yielding
ratio;
- RIVISE relevant provisions on test methods;
- DELETE Appendix A “Determination methods of steel bars at percentage
total elongation at maximum force”;
- DELETE Appendix B “Reference designations and chemical composition
of wire rods for cold rolled ribbed steel bars”.
This Standard was proposed by China Iron and Steel Association.
This Standard shall be under the jurisdiction of China National Standardization
Technology Committee (SAC/TC 183).
Drafting organizations of this Standard. Central Research Institute of Building
and Construction Co., Ltd., Anyang Heli Techtronic Co., Ltd., Anhui BRC & Ma
Steel Weldmesh Co., Ltd., Silvery Dragon Prestressed Materials Co., Ltd.
Tianjin, and China Metallurgical Information and Standardization Institute.
Main drafters of this Standard. Yue Qingrui, Feng Chao, Tao Ran, Zhai Wen,
Guo Sihong, Ai Tieling, Li Yajie, Zhang Pingyuan, Xie Zhian, Liu Baoshi, Wang
Xianhua, Du Ruiqing, Zhang Ying, Wang Yujie.
Cold rolled ribbed steel bars
1 Scope
This Standard specifies the terms and definitions, classification, designation,
size, shape, weight, allowable deviation, technical requirements, test methods,
inspection rules, packaging, marking, and quality certificate of cold rolled ribbed
steel bars.
This Standard is applicable to cold rolled ribbed steel bars for prestressed
concrete and ordinary reinforced concrete, and cold rolled ribbed steel bars
(known as steel bars for short hereinafter) for manufacturing welded mesh.
2 Normative references
The following documents are essential to the application of this document. For
the dated references, only the versions with the dates indicated are applicable
to this document. For the undated references, the latest version (including all
the amendments) are applicable to this document.
GB/T 2101 General requirement of acceptance packaging marking and
certification for section steel
GB/T 2103 General requirements for acceptance, packing, marking and
quality certification of steel wire
GB/T 17505 Steel and steel products General technical delivery
requirements
GB/T 21839 Steel for prestressed concrete - Test methods
GB/T 28899 Wire rods for cold rolled ribbed steel bars
GB/T 28900 Test methods of steel for reinforcement of concrete
YB/T 081 Rule for Rounding Off of Numerical Values and Judgement of
Testing Values for Technical Standards of Metallurgy
3 Terms and definitions
The following terms and definitions are applicable to this document.
The range of nominal diameter of CRB550, CRB600H, and CRB680H steel
bars is 4 mm~12 mm. The nominal diameter of CRB650, CRB800, and
CRB800H is 4 mm, 5 mm, and 6 mm.
5.2 Shape
5.2.1 The transverse ribs on the surface of steel bars shall conform to the
provisions of 5.2.1.1~5.2.1.6.
5.2.1.1 The transverse ribs of two-sided and three-sided ribbed steel bars shall
be crescent. The longitudinal section of transverse ribs of four-sided ribbed
steel bars shall be crescent and shall not intersect with the transverse ribs.
5.2.1.2 Transverse ribs shall be uniformly distributed along the circumferential
ring of the cross section of steel bars. The inclination of one rib of two-sided
ribbed steel bars shall be reversed with the other rib. The inclination of one rib
of three-sided ribbed steel bars shall be reversed with the other two ribs. The
inclination of the two adjacent transverse ribs of four-sided ribbed steel ribs
shall be opposite to that of the other two transverse ribs.
5.2.1.3 The included angle β between the center line of the transverse rib and
the longitudinal axis of the steel bar of two-sided and three-sided ribbed steel
bars is 40°~60°. The included angle between the axis of the transverse rib and
the axis of the steel bar of four-sided ribbed steel bars shall be 40°~70°; the
angle between the two rows of ribs can be 35°~75°.
5.2.1.4 The bevel angle α between the two sides of the transverse rib and the
surface of the steel bar of two-sided and three-sided ribbed steel bars shall not
be less than 45°. The bevel angle α between the two sides of the transverse rib
and the surface of the steel bar of four-sided ribbed steel bars shall not be less
than 40°. The transverse rib shall intersect the surface of the steel bar in an arc.
5.2.1.5 The sum of rib spacing of two-sided and three-sided ribbed steel bars
shall not be greater than 20% of the nominal circumference (∑fi ≤ 0.2πd). The
sum of rib spacing of four-sided ribbed steel bars shall not be greater than 25%
of the nominal circumference (∑fi ≤ 0.25πd).
5.2.1.6 The specific rib area fr shall be determined by the equation (1).
Where.
K=2, 3, or 4 (two-sided ribs, three-sided ribs, or four-sided ribs);
demand parties, it can also be delivered according to a specified length. When
the steel bar is delivered according to a specified length, the length and
allowable deviation shall be determined through consultation between the
supply-demand parties.
5.5 Bending
The bending per meter of straight steel bars shall not be more than 4 mm. The
total bending shall not be greater than 0.4% of the total length of the steel bar.
5.6 Weight
5.6.1 The weight of a coiled steel bar shall not be less than 100 kg. Each coil
shall be made up of a steel bar. When CRB650, CRB680H, CRB800, CRB800H
are used as steel bars for prestressed concrete, there shall be no welded joints.
5.6.2 The straight steel bar, according to the same designation, the same
specification, and the same length, shall be delivered in bundles. The weight of
the bundle shall be determined by consultation between the supply-demand
parties.
6 Technical requirements
6.1 Raw material
The raw material for manufacturing steel bars shall be in accordance with the
provisions of GB/T 28899. The wire rods produced according to other standards
can also be used.
6.2 Delivery state
The steel bar is delivered in cold working state. It is allowed that low
temperature tempering is implemented after cold rolling.
6.3 Mechanical and processing properties
6.3.1 The mechanical and processing properties of steel bars shall conform to
the provisions of Table 3. When carrying out a bending test, there shall be no
crack on the surface of the bent part. The bending radius of repeated bending
test shall conform to the provisions of Table 4.
7.3.2 The sample may be mechanically straightened. But there shall not be any
heat treatment and other cold working.
7.3.3 The initial test force applied to the sample is that, 70% of the nominal
tensile strength of the sample multiplies by the nominal cross-sectional area of
the sample.
7.3.4 The loading speed is 200 MPa/min±50 MPa/min. The initial load shall be
completed in 3 min~5 min. After holding the load for 2 min, the relaxation value
shall be recorded.
7.3.5 The sample length is not less than 60 times the nominal diameter.
7.3.6 The relaxation rate of 1000 h is allowed to be calculated from the test data
of at least 120 h.
7.4 Size measurement
7.4.1 The height of the transverse rib is the average value of the height of each
column of transverse ribs of the same section. MEASURE the average distance
to determine the distance between transverse ribs, that is, MEASURE the
center distance between the 1st and 11th transverse ribs in the same column
and DIVIDE it by 10, and OBTAIN the average value of distance between
transverse ribs.
7.4.2 The size measurement shall be accurate to 0.02 mm.
7.5 Measurement of weight deviation
When measuring the weight deviation of steel bar, the sample length shall not
be less than 500 mm. Length measurement shall be accurate to 1 mm. Weight
measurement shall be accurate to 1 g. The weight deviation of steel bar (%)
shall be calculated according to the equation (3).
7.6 Rounding off for values
The rounding off and determination for values of the inspection results shall
conform to the provisions of YB/T 081.
8 Inspection rules
8.1 Inspection and acceptance
Weight deviation
Actual weight of sample - (length of sample x theoretical weight)
Length of sample x theoretical weight
The inspection and acceptance of steel bar shall be carried out by the Quality
Supervision Department of the supply party. The demand party shall have the
right to inspect.
8.2 Batching rules
The steel bars shall be inspected and accepted in batches. Each batch shall be
made up of the steel bars of the same designation, same shape, same
specification, same production process, and same delivery state. Each batch
shall not be more than 60 t.
8.3 Sampling quantity
The sampling quantity of the inspection of steel bar shall be in accordance with
the provisions of Table 5.
8.4 Rules for re-inspection and determination
The rules for re-inspection and determination of steel bar shall conform to the
provisions of GB/T 17505.
9 Packaging, marking, and quality certificate
9.1 Each coil (bundle) of steel bars shall be tied up evenly for not less than 3
lines. The end socket shall be bent into the coil.
9.2 The steel bar shall be rolled with obvious designation-marks. The distance
between marks is twice that between transverse ribs; one transverse rib within
the distance between marks shall be deleted, as shown in Figure 4. It shall add
a short transverse rib within the third distance between marks to high-
elongation cold rolled ribbed steel bars, as shown in Figure 5. Steel bars can
also be rolled with the factory name or logo.
9.3 There shall be not less than two signs hanging on each coil (bundle) of steel
bars, which indicate the manufacturer, date of production, designation-number
and specification of the steel bar.
9.4 The packaging, marking, and quality certificate of steel bars, except as
stated above, shall comply with the relevant provisions of GB/T 2101 or GB/T
2103.
......
GB/T 13788-2008 (GB 13788-2008)
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 77.140.60
H 44
GB/T 13788-2008
Replacing GB 13788-2000
Cold Rolled Ribbed Steel Wires and Bars
ISSUED ON. JUNE 17, 2008
IMPLEMENTED ON. JUNE 01, 2009
Issued by. General Administration of Quality Supervision, Inspection and
Quarantine;
Standardization Administration of PRC.
Table of Contents
Foreword ... 3
1 Scope .. 4
2 Normative References ... 4
3 Terms and Definitions ... 5
4 Classification and Designation ... 5
5 Dimension, Shape, Weight and Permissible Deviation .. 5
6 Technical Requirements ... 10
7 Test Methods ... 11
8 Inspection Rules ... 12
9 Package, Marking and Quality Certificate .. 13
Appendix A (Normative) Determination of Steel Bar at the Total Elongation with
Maximum Force ... 15
Appendix B (Informative) Reference Designations and Chemical Compositions
of Coils for Cold Rolled Ribbed Steel Wires and Bars ... 17
Foreword
This Standard replaced GB 13788-2000 Cold Rolled Ribbed Steel Wires and Bars.
Compared with GB 13788-2000, this Standard has the major changes as follows.
--- Deleted Designation-CRB1170 steel bars;
--- Added the indicator requirements for total elongation under maximum force;
--- Modified the yield ratio from 1.05 to 1.03;
--- Modified the load-lasting time in the stress relaxation test method to be 2min;
adopt 120h to calculate the relaxation rate of 1000h;
--- Improve the indicator of proof strength at non-proportional extension.
This Standard’s clauses are mandatory; thereof, the transvers rig height at 1/4 of h1/4
and transverse rib top width of b in Table 1, 5.4, 5.6, 6.1, 6.3.2 and Appendix B are
non-mandatory clauses; while the rest clauses are mandatory.
Appendix A in this Standard is normative; while Appendix B is informative.
This Standard was proposed by China Iron and Steel Industry Association.
This Standard shall be under the jurisdiction of National Technical Committee for
Standardization of Steel.
Drafting organizations of this Standard. China Jingye Engineering Technology Co., Ltd.,
China National Construction Steel Quality Supervision and Test Center, China
Metallurgical Information and Standardization Institute, Anyang Heli High-Speed Cold-
Rolled Co., Ltd., and ShenYang Xinfeng Cold Rolling Co., Ltd.
Chief drafting staffs of this Standard. Li Peixun, Zhang Ying, Feng Chao, Tao Ran, Di
Wenhai and Wu Chunju.
The historical editions replaced by this Standard are as follows.
--- GB 13788-1992, GB 13788-2000.
Cold Rolled Ribbed Steel Wires and Bars
1 Scope
This Standard specifies definitions, classification, designation, dimension, shape,
weight and permissible deviation, technical requirements, test methods, inspection
rules, package, marking and quality certificate of cold rolled ribbed steel wires and bars.
This Standard is applicable to the cold rolled ribbed steel wires and bars used for
prestressed concrete and ordinary reinforced concrete; it is also applicable to the cold
rolled ribbed steel wires and bars used for manufacture of welded mesh (hereinafter
referred to as steel bar).
2 Normative References
The provisions in following documents become the provisions of this Standard through
reference in this Standard. For dated references, the subsequent amendments
(excluding corrigendum) or revisions do not apply to this Standard, however, parties
who reach an agreement based on this Standard are encouraged to study if the latest
versions of these documents are applicable. For undated references, the latest edition
of the referenced document applies.
GB/T 222 Permissible Tolerances for Chemical Composition of Steel Products
GB/T 228 Metallic Materials - Tensile Testing at Ambient Temperature (GB/T 228-
2002, ISO 6892.1998 (E), EQV)
GB/T 232 Metallic Materials - Bend Test (GB/T 232-1999, ISO 7438.1985 (E), EQV)
GB/T 238 Metallic Materials - Wire - Reverse Bend Test
GB/T 701 Hot-Rolled Low Carbon Steel Wire Rods
GB/T 2101 General Provisions on Acceptance, Package, Marking and Quality
Certificate for Profile Steel
GB/T 2103 General Requirements for Acceptance, Packing, Marking and Quality
Certification of Steel Wire
GB/T 4354 Hot Rolled Quality Carbon Steel Wire Rods
GB/T 10120 Metallic Materials - Stress Relaxation Test
GB/T 17505 Steel and Steel Products General Technical Delivery Requirements
YB/T 081 Rule for Rounding Off of Numerical Values and Judgement of Testing
Values for Technical Standards of Metallurgy
3 Terms and Definitions
The following terms and definitions are applicable to this Standard.
3.1 Cold-rolled ribbed steel wires and bars
After cold-rolling of hot-rolled steel wire rod, there are three-or-two-side transverse ribs
on its surface evenly distributed along the length direction.
3.2 Nominal diameter
The nominal diameter of plain bars with equivalent cross-section area.
3.3 Specific projected rib area
Ration of product AMONG transvers rib’s projected area on the perpendicular plane of
steel bar axis, nominal perimeter, AND transverse rib spacing.
3.4 Rib spacing
The projected chord length of discontinuous part of transverse rib, on the steel bar
circumference, perpendicular to the steel bar axial plane.
4 Classification and Designation
The designation of cold rolled ribbed steel wires and bars consists of CRB and
minimum tensile strength. C, R, B are the initials of Cold rolled, Ribbed, and Bar. The
cold rolled ribbed steel bar can be divided into four designations such as CRB550,
CRB650, CRB800, CRB970. CRB550 is the steel bar for ordinary reinforced concrete;
other designations are the steel bars for prestressed concrete.
5 Dimension, Shape, Weight and Permissible
Deviation
5.1 Nominal diameter range
treatment and other cold processing.
7.3.3 The initial test force applied to the specimen is 70% nominal tensile strength of
specimen multiplied by nominal cross-sectional area of specimen.
7.3.4 The loading speed is 200MPa/min±50MPa/min; start to record the relaxation
value after loading 3min~5min of the initial load and 2min of load-lasting.
7.3.5 The specimen length shall be no less than 60 times of nominal diameter.
7.3.6 At least 120h of test data is allowed to use to calculate the 1000h relaxation
rate.
7.4 Dimension measurement
7.4.1 The measurement of rib height shall measure the height of each column rib
with the same cross-section, then take the average value; the rib spacing shall
measure the average spacing; namely, take the center distance of the first and the
eleventh rib at the same column divided by 10; namely, the average value of rib spacing.
7.4.2 The accuracy of dimension measurement shall be 0.02mm.
7.5 Measurement of weight deviation
When measuring the weight deviation of steel bar, the specimen length shall be no
less than 500mm. The length measurement shall be accurate to 1mm; weight
measurement shall be accurate to 1g.
Weight deviation of steel bar shall be calculated as per Formula (3).
7.6 The rounding off and judgement of test result shall conform to the provisions of
YB/T 081.
8 Inspection Rules
8.1 Inspection and acceptance
The inspection and acceptance of steel bar shall be performed by the quality
supervision department of the supplier. The purchaser reserves the right to inspect.
The inspection and acceptance of steel bar shall be performed as per the provisions
of GB/T 17505.
Weight Deviation
Specimen’s actual weight – (specimen length × theoretical weight)
(specimen length × theoretical weight)
8.2 Batching rules
The steel bar shall be inspected and accepted in batches; each batch consists of the
steel bars with the same designation, the same shape, the same specification, the
same process, and the same delivery state; each batch is no greater than 60t.
8.3 Sampling quantity
The sampling quantity for inspection of steel bar shall conform to the provisions of
Table 4.
8.4 Re-inspection and judgment rules
The re-inspection and judgment rules of steel bar shall conform to the provisions of
GB/T 17505.
9 Package, Marking and Quality Certificate
9.1 Each coil (bundle) of steel bars shall be bundled for at least 3 laps; the end shall
be bent into the coil.
9.2 The steel bar shall be rolled obvious designation mark; the mark spacing is twice
of the rib spacing; one rib within the mark spacing shall be canceled, which is shown
in Figure 3; the steel bar can also be rolled with factory name or logo.
9.3 Each coil (bundle) of steel bar shall be suspended with no less than 2 signboards,
which indicate the manufacturer, production date, steel bar designation and
specification.
9.4 In addition to the above provisions, the steel bar’s package, marking and quality
certificate shall conform to the relevant provisions of GB/T 210...
......
| Standard ID | GB 13788-2024 (GB13788-2024) | | Description (Translated English) | Cold rolled ribbed steel bars | | Sector / Industry | National Standard | | Classification of Chinese Standard | H44 | | Classification of International Standard | 77.140.15 | | Word Count Estimation | 12,141 | | Date of Issue | 2024-06-25 | | Date of Implementation | 2024-09-25 | | Administrative Organization | Ministry of Industry and Information Technology of the People's Republic of China | | Proposing organization | Ministry of Industry and Information Technology of the People's Republic of China | | Issuing agency(ies) | State Administration for Market Regulation, National Standardization Administration | | Standard ID | GB/T 13788-2017 (GB/T13788-2017) | | Description (Translated English) | Cold rolled ribbed steel bars | | Sector / Industry | National Standard (Recommended) | | Classification of Chinese Standard | H44 | | Classification of International Standard | 77.140.60 | | Word Count Estimation | 11,185 | | Date of Issue | 2017-07-12 | | Date of Implementation | 2018-04-01 | | Older Standard (superseded by this standard) | GB/T 13788-2008 | | Quoted Standard | GB/T 2101; GB/T 2103; GB/T 17505; GB/T 21839; GB/T 28899; GB/T 28900; YB/T 081 | | Drafting Organization | China Metallurgical Building Research Institute Co., Ltd., Anyang Heli Chuang Metallurgical New Technology Co., Ltd., Anhui Maanshan Ironfield Steel Wire Mesh Co., Ltd., Tianjin Yinlong Prestressed Materials Co., Ltd., Metallurgical Industry Information Standards Institute | | Administrative Organization | National Standardization Technical Committee (SAC / TC 183) | | Proposing organization | China Iron and Steel Industry Association | | Issuing agency(ies) | General Administration of Quality Supervision, Inspection and Quarantine of the People Republic of China, China National Standardization Administration Committee | | Summary | This standard specifies the terms and definitions, classification, grades, dimensions, shapes, weights and tolerances of cold rolled ribbed bars, technical requirements, test methods, inspection rules, packaging, marking and quality certificates. This standard applies to prestressed concrete and ordinary reinforced concrete cold-rolled ribbed steel bars, but also for the manufacture of welded wire with cold-rolled ribbed steel bar (hereinafter referred to as steel). | | Standard ID | GB 13788-2008 (GB13788-2008) | | Description (Translated English) | [GB/T 13788-2008] Cold rolled ribbed steel wires and bars [replaced by GB/T 13788-2017] | | Sector / Industry | National Standard | | Classification of Chinese Standard | H44 | | Classification of International Standard | 77.140.60 | | Word Count Estimation | 12,148 | | Date of Issue | 2008-06-17 | | Date of Implementation | 2009-06-01 | | Older Standard (superseded by this standard) | GB 13788-2000 | | Quoted Standard | GB/T 222; GB/T 228; GB/T 232; GB/T 238; GB/T 701; GB/T 2101; GB/T 2103; GB/T 4354; GB/T 10120; GB/T 17505; YB/T 081 | | Drafting Organization | China Metallurgical Engineering Technology Co., Ltd. Beijing | | Administrative Organization | National Steel Standardization Technical Committee | | Regulation (derived from) | Announcement of Newly Approved National Standards No. 10 of 2008 (total 123) | | Proposing organization | China Iron and Steel Association | | Issuing agency(ies) | Administration of Quality Supervision, Inspection and Quarantine of People's Republic of China; Standardization Administration of China | | Summary | This Chinese standard specifies the rolled ribbed bars outline the definition, classification, grade, size, shape, weight and tolerances, technical requirements, test methods, inspection rules, packaging, marking and quality certificate. This standard applies to prestressed concrete and reinforced concrete with cold rolled ribbed steel, but also for the manufacture of welded cold-rolled ribbed steel bars. |
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