1 Scope
This standard specifies the terms and definitions, classification and marking, order contents, dimensions, profile, weight and permissible deviation, technical requirements, test methods, inspection rules, packaging, marking and quality certificate of steel strand for prestressed concrete.
This standard is applicable to the steel strand (hereinafter referred to as "strand") twisted with cold drawn plain steel wire and indented steel wire and used for prestressed concrete structure.
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 editions of the normative documents (including all the amendments) are applicable to this document.
GB/T 5223 Steel Wires for the Prestressing of Concrete
GB/T 21839 Steel for Prestressed Concrete - Test Methods
GB/T 24238 Hot-rolled Wire Rod for Prestressed Steel and Steel Strand
GB/T24242.2 Non-alloy Steel Wire Rods for Conversion to Wire - Part 2: Specific Requirements for General Purpose Wire Rod
GB/T24242.4 Non-alloy Steel Wire Rods for Conversion to Wire - Part 4: Specific Requirements for Wire Rod for Special Applications
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 purpose of this standard, the following terms and definitions apply.
3.1
Standard strand
The strand twisted by cold drawn plain steel wires.
3.2
Indented strand
The strand twisted by intended steel wires.
3.3
Compact strand
The strand formed by cold drawing after twisting.
3.4
Nominal diameter
The nominal size of the circumscribed circle diameter of strand.
3.5
Stabilizing treatment
The short-time heat treatment borne by strand under certain tension for the purpose of reducing stress relaxation during application.
4 Classification and Marking
4.1 Classification and Code
The strands are divided into the 8 types below by structure with the structure codes as:
a) The strand twisted by two steel wires 1×2
b) The strand twisted by three steel wires 1×3
c) The strand twisted by three indented wires 1×3I
Foreword i
1 Scope
2 Normative References
3 Terms and Definitions
4 Classification and Marking
4.1 Classification and Code
4.2 Marking
5 Order Contents
6 Dimension, Profile, Weight and Permissible Deviation
7 Technical Requirements
7.1 Manufacture
7.2 Mechanical Property
7.3 Surface Quality
7.4 Straightness of Strand
7.5 Fatigue Performance, Deflection Tensile Performance and Stress Corrosion Performance
8 Test Methods
8.1 Surface Inspection
8.2 Overall Dimension Inspection
8.3 Tensile Test
8.4 Stress Relaxation Property Test
8.5 Fatigue Test
8.6 Deflection Tensile Test
8.7 Stress Corrosion Test
8.8 Value Rounding
9 Inspection Rules
9.1 Delivery Inspection
9.2 Characteristic Value Inspection
10 Packaging, Marking and Quality Certificate
10.1 Packaging
10.2 Marking
10.3 Quality Certificate
Appendix A (Normative) Inspection Rules for Characteristic Value
