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.
1.4 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.
This standard is referenced in the 2015 International Building Code®.