This specification deals with the standard types and grade requirements of seven-wire, uncoated steel strands for use in the construction of pre-tensioned and post-tensioned pre-stressed concrete. The two types of strand are low-relaxation and stress-relieved (normal relaxation). The base metal shall be made of carbon steel and shall undergo stranding and continuous thermal and mechanical treatment. Mechanical testing methods shall be performed to determine the breaking strength, yield strength, elongation, and stress relaxation properties wherein the strand shall conform to the required mechanical attributes of the product. Final products shall be furnished on reels or in reelless packs for packaging and marked with two strong tags for identification. The requirements specified herein shall also be applicable for pre-stressed ground anchor construction.
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1.1 This specification covers two types and two grades of seven-wire, uncoated steel strand for use prestressed concrete construction. The two types of strand are low-relaxation and stress-relieved (normal-relaxation). Low-relaxation strand is to be regarded as the standard type. Stress-relieved (normal-relaxation) strand will not be furnished unless specifically ordered. Grade 250  and Grade 270  have minimum tensile strengths of 250 ksi [1725 MPa] and 270 ksi [1860 MPa], respectively, based on the nominal area of the strand.
1.2 A supplementary requirement (S1) is provided for use where bond strength testing of 0.600-in. [15.24-mm] diameter Grade 270  strand for applications in prestressed ground anchors is required by the purchaser. The supplementary requirement applies only when specified in the purchase order.
1.3 This specification is applicable for orders in either inch-pound units (as Specification A416) or in SI units (as Specification A416M).
1.4 The values stated in either inch-pound units or SI units are to be regarded separately as standard. Within the text, the SI units are shown in brackets. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the specification.
2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.
A981/A981M Test Method for Evaluating Bond Strength for 0.600-in. [15.24-mm] Diameter Steel Prestressing Strand, Grade 270 , Uncoated, Used in Prestressed Ground Anchors
A1061/A1061M Test Methods for Testing Multi-Wire Steel Strand
U.S. Military Standards
MIL-STD-129 Marking for Shipment and Storage
U.S. Federal Standard
Fed. Std. No. 123 Marking for Shipments (Civil Agencies)
prestressed concrete; seven-wire strand (tendon); steel wire;
ICS Number Code 77.140.15 (Steels for reinforcement of concrete)
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Citing ASTM Standards
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