Link points to Internet Archive / others. Not hosted by InfraLens. Details
IS 6006:1983 is the Indian Standard (BIS) for uncoated stress-relieved strand for prestressed concrete. This standard specifies the requirements for uncoated, stress-relieved, low relaxation steel strands used for prestressing concrete. It covers two-wire, three-wire, and seven-wire strands, detailing their manufacturing, dimensions, mechanical properties like breaking strength and elongation, and testing procedures.
uncoated stress-relieved strand for prestressed concrete
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
Practical Notes
! This version of the code has been superseded by IS 6006:2014 and should not be used for new projects. Always refer to the latest version.
! Ensure strands are free from loose rust, oil, and other contaminants before use to ensure a proper bond with concrete. A light film of rust that can be wiped off is generally acceptable.
! The relaxation properties are critical for long-term performance and calculating prestress losses. Always verify supplier test certificates for compliance.
Consolidated list per BIS. For the text of each amendment, refer to the BIS portal link above.
steelprestressed concretestrand
International Equivalents
Similar International Standards
ASTM A416/A416M-18ASTM International, USA
HighCurrent
Standard Specification for Steel Strand, Uncoated Seven-Wire for Prestressed Concrete
Specifies requirements for two grades of seven-wire, uncoated steel strand for use in prestressed concrete construction.
BS 5896:2012BSI, United Kingdom
HighCurrent
High tensile steel wire and strand for the prestressing of concrete - Specification
Covers requirements for high-tensile steel wire and seven-wire strand for prestressing, including relaxation properties.
EN 10138-3:2009CEN, European Union
HighCurrent
Prestressing steels - Part 3: Strand
Details the requirements for uncoated seven-wire strands made from cold-drawn wire, either stress-relieved or low-relaxation.
ISO 6934-4:2020ISO, International
HighCurrent
Steel for the prestressing of concrete — Part 4: Strand
Provides international specifications for seven-wire strands used in prestressed concrete applications.
Key Differences
≠IS 6006 defines a single strength level for each nominal diameter, whereas standards like ASTM A416 offer distinct strength grades (e.g., Grade 250 [1725] and Grade 270 [1860]).
≠The method for determining proof/yield stress varies. IS 6006 specifies a 0.2% proof stress, while ASTM A416 uses yield strength at 1% extension, and EN 10138-3 uses a 0.1% proof force.
≠Nominal breaking loads for equivalent diameters can differ. For example, the 12.7 mm strand in IS 6006 has a lower minimum breaking load (173.6 kN) than the Grade 270 1/2 in. (12.7 mm) strand in ASTM A416 (183.7 kN).
≠While IS 6006 diameters are direct metric conversions of imperial sizes (e.g., 12.70 mm), European standards like EN 10138-3 use rationalized metric sizes like 12.5 mm and 12.9 mm.
Key Similarities
≈All standards specify the construction of the product as a seven-wire strand, typically with six outer wires helically wound around a central straight wire.
≈All standards provide classifications for both 'Normal' (or Stress-Relieved) and 'Low Relaxation' strand, with very similar performance criteria for low relaxation properties (approx. 2.5% loss at 1000h at 70% load).
≈The requirement for ductility, as measured by minimum percentage elongation at fracture, is highly consistent, typically specified as 3.5% over a gauge length of around 600 mm.
≈All listed standards cover uncoated strand, meaning they do not include provisions for epoxy-coating or galvanizing which are covered by other specific standards.
Parameter Comparison
Parameter
IS Value
International
Source
Product Form
Uncoated seven-wire strand
Uncoated seven-wire strand
ASTM A416/A416M-18
Minimum Breaking Load (12.7 mm / 0.5 in. strand)
173.6 kN
183.7 kN (for Grade 270)
ASTM A416/A416M-18
Proof Stress Criterion
≥ 85% of breaking strength (at 0.2% offset)
≥ 88% of actual breaking force (at 0.1% offset)
EN 10138-3:2009
Minimum Elongation at Fracture
3.5% on 600 mm gauge length
3.5% on a gauge length of at least 610 mm
BS 5896:2012
Low Relaxation Limit (1000h)
Max 2.5% from 70% of specified breaking load
Max 2.5% from 70% of actual breaking force
EN 10138-3:2009
Nominal Mass (15.2 mm / 0.6 in. strand)
1102 g/m
1102 kg/km (equivalent to 1102 g/m)
ASTM A416/A416M-18
⚠ Verify details from original standards before use
Key Values5
Quick Reference Values
Minimum breaking strength of 15.2 mm seven-wire strand182.0 kN
Minimum breaking strength of 12.7 mm seven-wire strand129.5 kN
Minimum elongation at fracture (on 600 mm gauge length)3.5 %
Maximum 1000-h relaxation at 70% of min breaking strength5.0 %
Nominal diameter of largest seven-wire strand15.2 mm
Tables & Referenced Sections
Key Tables
Table 1 - Properties of Two- and Three-Wire Strands
Table 2 - Properties of Seven-Wire Strands
Table 3 - Coil Diameters
Table 4 - Permissible Tolerances on Diameter of Wires