Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard replaces GB/T 5223.3-2005, Steel bars for the prestressing of concrete. Compared with GB/T 5223.3-2005, this standard has technical changes as follows:
——The general relaxation variety of steel bars for the prestressing is canceled;
——The specifications of steel bar are added (see Chapter 6);
——The cross-sectional area measurement is canceled and the allowable deviation of the diameter is added in the plain bar (see 6.1);
——The measurement of the cross-sectional area of the helical grooved bar and the helical ribbed bar is modified to measure the weight per meter, and the weight deviation of the helical ribbed bar is adjusted (see 6.2 and 6.3);
——The disk weight requirement is increased (see 6.6)
——The measurement for dimensions of the steel bar is added (see 8.2.1);
——The test method is modified to conform to GB/T 21839 (see 8.4.1).
This standard is prepared by adopting the redrafting method with reference to ISO 6934-3:1991, Steel for the prestressing of concrete—Part 3: Quenched and tempered wire. This standard is not equivalent to ISO 6934-3: 1991 with the main difference as follows:
——The quenched & tempered steel wire is modified into a steel bars for the prestressing of concrete;
——The helical ribbed bar is added;
——The strength grading is added;
——The specifications of steel bar are added;
——The percentage elongation after fracture is added as a daily inspection project;
——The impact test of helical ribbed bar for mine support is added.
This standard was proposed by China Iron and Steel Association.
This standard was prepared by SAC/TC 183 (National Technical Committee 183 on Iron and Steel of Standardization Administration of China).
The previous editions of standard replaced by this standard are as follows:
——GB/T 4463-1984;
——GB/T 5223.3-2005.
Steel bars for the prestressing of concrete
1 Scope
This standard specifies the terms and definitions, classification, code and marking, order contents, dimension, shape, weight and permissible deviation, technical requirements, test methods, inspection rules, packaging, marking and quality certificate of steel bars for the prestressing of concrete.
This standard is applicable to the plain bar, helical grooved bar, helical ribbed bar, and ribbed bar for the prestressing of concrete.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 229 Metallic materials—Charpy pendulum impact test method
GB/T 2101-2008 General requirement of acceptance packaging, marking and certification for section steel
GB/T 2103-2008 General requirement of acceptance packaging, marking and certification for section steel
GB/T 14981-2009 Dimensions, shape, mass and tolerances for hot-rolled round wire rod
GB/T 21839 Steel for prestressed concrete—Test methods
GB/T 24587 Hot-rolled wire rods for prestressing steel bars of concrete
YB/T 081 Rule for rounding off of numerical values and judgment of testing values for technical standards of metallurgy
3 Terms and definitions
For the purposes of this standard, the following terms and definitions apply.
3.1
quenched & tempered bar
steel bar that is obtained in the process of the wire rod is heated to austenitizing temperature and then rapidly cooled, and then heated and tempered below the intersection temperature.
3.2
relaxation
phenomenon that stress decreases with time at a constant length.
3.3
plain bar
steel bar with a circular cross section.
3.4
helical grooved bar
steel bar with a continuous helical groove at regular intervals along the longitudinal direction of the surface [see Figure 1a), and Figure 1b)].
3.5
helical ribbed bar
steel bar with a continuous helical rib at regular intervals along the longitudinal direction of the surface (see Figure 2).
3.6
ribbed bar
steel bar with a generally circular cross section and a ribbed surface [see Figure 3a), and Figure 3b)].
3.7
longitudinal rib
uniform continuous rib parallel to the axis of the steel bar.
3.8
transverse rib
other ribs that are not parallel to the axis of the steel bar.
4 Classification, code and marking
4.1 Classification
Steel bars are divided into four types of plain bar, helical grooved bar, helical ribbed bar, and ribbed bar according to their shapes.
4.2 Code
Steel bars for the prestressing of concrete PCB
Plain bar P
Helical grooved bar HG
Helical ribbed bar HR
Ribbed bar R
Low relaxation L
4.3 Marking
4.3.1 Marking information
The marking of products delivered according to this standard shall include the following information:
Steel bars for the prestressing, nominal diameter, nominal tensile strength, code, ductility grade (ductility 35 or 25), low relaxation (L), and standard number.
4.3.2 Marking example
Example: Helical grooved bar for the prestressing of concrete with a nominal diameter of 9.0 mm, a nominal tensile strength of 1420 MPa and ductility grade of 35, marked as: PCB 9.0-1420-35-L-HG-GB/T 5223.3.
5 Order contents
The order contract according to this standard shall include the following contents:
a) No. of this standard;
b) Product name;
c) Product code;
d) Nominal diameter;
e) Strength and ductility grade;
f) Quantity;
g) Other requirements.
6 Dimension, appearance, weight and permissible deviation
The dimension, weight and permissible deviation of the plain bar shall meet the requirements of Table 1. See Table 1 for theoretical weight per meter.
Table 1 Dimension, permissible deviation, and theoretical weight per meter of the plain bar
Nominal diameter Dn /mm Permissible deviation of the diameter /mm Nominal cross section Sn /mm2 Theoretical weight per meter (g/m)
6 ±0.10 28.3 222
7 38.5 302
8 50.3 295
9 ±0.12 63.6 499
10 78.5 616
11 95.0 746
12 113 887
13 133 1044
14 154 1209
15 177 1389
16 201 1578
Note: The theoretical weight per meter = nominal cross-sectional area × steel density calculation. The steel density of theoretical per meter of steel bar is 7.85g / cm3.
6.2 The dimensions, weights and permissible deviations of helical grooved bar shall comply with the requirements of Table 2, and the shapes are as shown in Figure 1) and Figure 1b).
Keys:
D —— the diameter of the outer contour;
a —— the depth of the helical groove;
b —— the width of the helical groove;
c —— the lead of the helical groove.
a) Three-helical grooved bar
Keys:
D —— the diameter of the outer contour;
a —— the depth of the helical groove;
b —— the width of the helical groove;
c —— the lead of the helical groove.
b) Six-helical grooved bar
Note: The 7.1 mm helical grooved bar is equipped with 3 helical grooves, while the 9.0 mm to 14.0 mm helical grooved bar is equipped with 6 helical grooves.
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Classification, code and marking
5 Order contents
6 Dimension, appearance, weight and permissible deviation
7 Technical requirements
8 Test methods
9 Inspection rules
10 Packaging, marking and quality certificate
