ASTM A910/A910M-99

Standard Specification for Uncoated, Weldless, 2- and 3-Wire Steel Strand for Prestressed Concrete

SCOPE
1.1 This specification covers two types and two grades of 2- and 3-wire, uncoated steel strand for use in pretensioned and posttensioned prestressed concrete construction. The two types of strand are low-relaxation and stress-relieved (normal-relaxation). Low-relaxation shall be regarded as the standard type. Stress-relieved (normal-relaxation) strand will not be furnished unless specifically ordered, or by arrangement between purchaser and supplier. The two grades are 250 and 270. Grades 250 and 270 have minimum tensile strengths of 250000 psi (1725 MPa) and 270000 psi (1860 MPa) respectively, based on the nominal area of the strand.
1.2 The values stated in inch-pound units are to be regarded as the standard. The SI units given in parentheses are provided for information only.

General Information

• Status: Historical
• Publication Date: 09-Sep-1999
• ICS: 77.140.15 - Steels for reinforcement of concrete
• Technical Committee: A01 - Steel, Stainless Steel and Related Alloys
• Drafting Committee: A01.05 - Steel Reinforcement

Relations

• Replaced By: ASTM A910/A910M-05 - Standard Specification for Uncoated, Weldless, 2- and 3-Wire Steel Strand for Prestressed Concrete
• Effective Date: 01-Mar-2005

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: A 910/A 910M – 99
Standard Specification for
Uncoated, Weldless, 2- and 3-Wire Steel Strand for
Prestressed Concrete
ThisstandardisissuedunderthefixeddesignationA910/A910M;thenumberimmediatelyfollowingthedesignationindicatestheyear
of original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.
A superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope Fed. Std. No. 123 Marking for Shipments (CivilAgencies)
1.1 Thisspecificationcoverstwotypesandtwogradesof2-
3. Terminology
and 3-wire, uncoated steel strand for use in pretensioned and
3.1 Definitions of Terms Specific to This Standard:
posttensionedprestressedconcreteconstruction.Thetwotypes
3.1.1 strand, n—allstrandsshallbecomprisedofeithertwo
of strand are low-relaxation and stress-relieved (normal-
wires or three wires helically wound around each other; they
relaxation). Low-relaxation shall be regarded as the standard
shallhaveauniformpitchofnotlessthan12normorethan16
type. Stress-relieved (normal-relaxation) strand will not be
times the nominal diameter of the strand.
furnished unless specifically ordered, or by arrangement be-
3.1.2 Discussion—The direction of lay may be either right
tween purchaser and supplier. The two grades are 1725 (250)
or left hand; however, strands of different lays shall not be
and 1860 (270). Grades 250 and 270 have minimum tensile
spliced together.
strengths of 1725 MPa (250 ksi) and 1860 MPa (270 ksi)
respectively, based on the nominal area of the strand.
4. Ordering Information
1.2 The values stated in either inch-pound units or SI units
4.1 Orders for 2- or 3-wire low-relaxation or stress-relieved
are to be regarded as the standard. Within the text, the
(normal-relaxation) strand under this specification should in-
inch-pound units are shown in parentheses. The values stated
clude the following information:
in each system are not exact equivalents; therefore, each
4.1.1 Quantity (meters [feet]),
system must be used independently of the other. Combining
4.1.2 Diameter of strand (Section 7),
values from the two systems may result in nonconformance
4.1.3 Number of wires (2 or 3),
with the specification.
4.1.4 Grade of strand (see 1.1 and Table 1 and Table 2),
4.1.5 Type of strand (see 1.1 and Table 2),
2. Referenced Documents
4.1.6 Packaging (Section 14),
2.1 ASTM Standards:
4.1.7 ASTM designation and year of issue, and
A370 TestMethodsandDefinitionsforMechanicalTesting
2 4.1.8 Special requirements, if any.
of Steel Products
E328 MethodsforStressRelaxationTestsforMaterialsand
NOTE 1—A typical ordering description is as follows: 100000 m
Structures (325000 ft) of 6.2 mm (0.244 in.) diameter, three wire, Grade 1860 MPa
(270 ksi), low-relaxation strand in 10000 m (32500 ft) reelless packs
2.2 U.S. Military Standards:
4 conforming to ASTM A910/A910M–XX.
MIL-STD-129 Marking for Shipment and Storage
MIL-STD-163 Steel Mill Products Preparation for Ship-
5. Materials and Manufacture
ment and Storage
5.1 Base Metal—The base metal shall be carbon steel of
2.3 Federal Standard:
such quality that when drawn to wire, fabricated into strand
and then thermally treated, it shall have the properties and
characteristics prescribed in this specification.
This specification is under the jurisdiction ofASTM CommitteeA-1 on Steel,
Stainless Steel, and RelatedAlloys and is the direct responsibility of Subcommittee
5.2 Wire—The wire from which the strand is to be fabri-
A01.05 on Steel Reinforcement.
cated shall be round and have a dry-drawn finish.
Current edition approved Sept. 10, 1999. Published December 1999. Originally
published as A910–92. Last previous edition A910– 94.
NOTE 2—This product is a composite of two or three wires and is
Annual Book of ASTM Standards, Vol 01.04.
produced to mechanical properties only, of which the chemistry of all
Annual Book of ASTM Standards, Vol 03.01.
wires or any individual wire is not pertinent to this application, and heat
AvailablefromStandardizationDocumentsOrderDesk,Bldg.4SectionD,700
identity is not necessarily maintained. It is possible that wire from more
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A 910/A 910M – 99
TABLE 1 Breaking Strength Requirements
Description and Diameter of Strand
Breaking Strength of Steel Area of Weight of
Strand Strand Strand
in. mm
Nominal Nominal
2 2
Description Description lbf kN in. mm lbs/1000 ft kg/1000 m
Diameter Diameter
GRADE 250 (1725 MPa)
2 3 0.114 0.228 2 3 2.90 5.8 5000 22.2 0.020 13.2 69.9 104.0
3 3 0.089 0.189 3 3 2.25 4.8 4750 21.1 0.019 12.0 63.3 94.2
3 3 0.095 0.205 3 3 2.40 5.2 5250 23.4 0.021 13.6 71.9 107.0
3 3 0.114 0.244 3 3 2.90 6.2 7750 34.5 0.031 19.8 104.0 155.0
3 3 0.118 0.256 3 3 3.00 6.5 8250 36.7 0.033 21.3 112.0 167.0
3 3 0.138 0.295 3 3 3.50 7.5 11 250 50.0 0.045 29.0 153.0 228.0
3 3 0.158 0.340 3 3 4.00 8.6 14 500 64.5 0.058 37.4 200.6 298.4
GRADE 270 (1860 MPa)
2 3 0.114 0.228 2 3 2.90 5.8 5400 24.0 0.020 13.2 69.9 104.0
3 3 0.089 0.189 3 3 2.25 4.8 5130 22.8 0.019 12.0 63.3 94.2
3 3 0.095 0.205 3 3 2.40 5.2 5670 25.2 0.021 13.6 71.9 107.0
3 3 0.114 0.244 3 3 2.90 6.2 8370 37.2 0.031 19.8 104.0 155.0
3 3 0.118 0.256 3 3 3.00 6.5 8910 39.6 0.033 21.3 112.0 167.0
3 3 0.138 0.295 3 3 3.50 7.5 12 150 54.0 0.045 29.0 153.0 228.0
3 3 0.158 0.340 3 3 4.00 8.6 15 660 69.7 0.058 37.4 200.6 298.4
TABLE 2 Yield Strength Requirements
Description and Diameter of Strand Minimum Load at 1 % Extension
Initial Load
Stress-Relieved
in. mm Low Relaxation
(Normal Relaxation)
Nominal Nominal
Description Description lbf kN lbf kN lbf kN
Diameter Diameter
GRADE 250 (1725 MPa)
2 3 0.114 0.228 2 3 2.90 5.8 500 2.2 4250 18.9 4500 20.0
3 3 0.089 0.189 3 3 2.25 4.8 475 2.1 4038 18.0 4275 19.0
3 3 0.095 0.205 3 3 2.40 5.2 525 2.3 4463 20.0 4725 21.0
3 3 0.114 0.244 3 3 2.90 6.2 775 3.5 6588 29.3 6975 31.0
3 3 0.118 0.256 3 3 3.00 6.5 825 3.7 7013 32.2 7425 33.0
3 3 0.138 0.295 3 3 3.50 7.5 1250 5.0 9563 42.5 10 125 45.0
3 3 0.158 0.340 3 3 4.00 8.5 1450 6.5 12 325 54.8 13 050 11.7
GRADE 270 (1860 MPa)
2 3 0.114 0.228 2 3 2.90 5.8 540 2.4 4590 20.4 4860 21.6
3 3 0.089 0.189 3 3 2.25 4.8 513 2.3 4360 19.4 4617 20.5
3 3 0.095 0.205 3 3 2.40 5.2 567 2.5 4820 21.4 5103 22.7
3 3 0.114 0.244 3 3 2.90 6.2 837 3.7 7115 31.6 7533 33.5
3 3 0.118 0.256 3 3 3.00 6.5 891 4.0 7574 33.7 8019 36.0
3 3 0.138 0.295 3 3 3.50 7.5 125 5.4 10 328 45.9 10 125 45.0
3 3 0.158 0.340 3 3 4.00 8.6 566 7.0 13 311 59.2 14 094 62.7
than one heat may be used in the manufacture of a reel or pack.
6.2 Breaking Strength—The breaking strength of the fin-
Traceability is based on pack identity as maintained and reported by the
ished strand shall conform to the requirements prescribed in
manufacturer.
Table 1.
5.3 Thermal Treatment—After stranding, low-relaxation
6.3 Yield Strength—Yield strength in kN (lbs) is measured
strand shall be subjected to a continuous thermal-mechanical
at1%extensionunderload.Theminimumyieldstrengthshall
treatment to produce the prescribed mechanical properties. For
be 90% for low-relaxation strand and 85% for stress-relieved
stress-relieved (normal-relaxation) strand, only thermal treat-
(normal relaxation) strand of the breaking strength listed in
ment is necessary. Temper colors that result from the stress-
Table 1. Initial loads for the test and minimum yield strengths
relieving operation are considered normal for the finished
are listed in Table 2.
appearance of this strand.
6.4 Elongation—The total elongation under load shall not
6. Mechanical Properties
be less than 3.5%. In practice the total elongation value may
be determined by adding to the 1.0% yield extension the
6.1 Methods of testing for mechanical properties are in
percent extension or movement between the jaws gripping the
Annex A7 of Test Methods and Definitions A370. Low-
strand after yield determination. The percent is calculated on
relaxation strand shall also be tested as prescribed in Methods
E328. the new base length of jaw-to-jaw distance.
A 910/A 910M – 99
6.5 Relaxation Properties—Low-relaxation strand shall 8. Workmanship, Finish and Appearance
have relaxation losses of not more than 2.5% when initially
8.1 Joints:
loaded to 70% of specified minimum breaking strength or not
8.1.1 There shall be no strand splices in any length of the
more than 3.5% when loaded to 80% of specified minimum
completed strand.
breaking strength of the strand after 1000 h tested under
8.1.2 There shall be no wire welds made in the finished
conditions li
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