【国外标准】 Standard Specification for Uncoated, Weldless, 2-Wire and 3-Wire Steel Strand for Prestressed Concrete

This specification covers two types and two grades of 2- and 3-wire, uncoated weldless steel and strand for use in pretensioned and posttensioned prestressed concrete construction. One specimen for test shall be taken from each production lot of finished strand and tested for breaking strength, yield strength and elongation. Strands of Grades 250 and 270 shall conform to specified breaking strength and yield strength requirements. Low relaxation strand shall also be tested as prescribed.1.1 This specification covers two types and two grades of 2-wire and 3-wire, uncoated steel strand for use in prestressed concrete construction. The two types of strand are low-relaxation and stress-relieved (normal-relaxation). Low-relaxation is to be regarded as the standard type. Stress-relieved (normal-relaxation) strand will not be furnished unless specifically ordered. The two grades are 250 [1725] and 270 [1860]. Grades 250 [1725] and 270 [1860] 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 This specification is applicable for orders in either inch-pound units (as Specification A910) or in SI units (as Specification A910M).1.3 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 are not 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.1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.