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.