1.1 ,This specification covers two types and two grades of indented seven-wire uncoated, steel strand for use in prestressed concrete construction. The two types of strand are low-relaxation and stress-relieved (normal-relaxation). Grade 250I [1725I] and Grade 270I [1860I] have minimum tensile strengths of 250 ksi [1725 MPa] and 270 ksi [1860 MPa], respectively, based on the nominal area of the strand.