【国外标准】 Standard Specification for Steel Wire, Indented, Low-Relaxation for Prestressed Concrete

This specification covers uncoated, deformed, stress-relieved, and low-relaxation wire for use as prestressed tendons in concrete railroad ties. Deformed wires with nominal diameters shall be supplied in coils and shall conform to specified values of breaking strength requirements. The relaxation losses of normal stress-relieved and low-relaxation stress-relieved wires should not exceed the specified limits. The two acceptable types of deformed wire shall have specific dimensions of deformations, where the depth of indent shall be the average depth of six or more random indents measured at maximum depth. The material shall be tested on and shall conform to specified values of the following mechanical properties: breaking strength, load at 1% extension, elongation, bending, and relaxation.1.1 This specification covers indented, low-relaxation steel wire for use in prestressed concrete.1.2 The text of this specification contains notes or footnotes, or both, that provide explanatory material. Such notes and footnotes do not contain any mandatory information.1.3 This specification is applicable for orders in either inch-pound units (as Specification A881) or in SI units (as Specification A881M).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.1.5 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.