GB/T 13788-2017 English PDF (GBT13788-2017)

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GB/T 13788-2017: Cold rolled ribbed steel bars
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 and
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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 and 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