Standard Specification for Low-Relaxation, Seven-Wire Steel Strand for Prestressed Concrete
Standard Specification for Low-Relaxation, Seven-Wire Steel Strand for Prestressed Concrete
ABSTRACT This specification deals with the standard types and grade requirements of seven-wire, uncoated steel strands for use in the construction of pre-tensioned and post-tensioned pre-stressed concrete. The two types of strand are low-relaxation and stress-relieved (normal relaxation). The base metal shall be made of carbon steel and shall undergo stranding and continuous thermal and mechanical treatment. Mechanical testing methods shall be performed to determine the breaking strength, yield strength, elongation, and stress relaxation properties wherein the strand shall conform to the required mechanical attributes of the product. Final products shall be furnished on reels or in reelless packs for packaging and marked with two strong tags for identification. The requirements specified herein shall also be applicable for pre-stressed ground anchor construction. SCOPE 1.1 This specification covers two grades of low-relaxation, seven-wire steel strand for use in prestressed concrete construction. Grade 250 [1725] and Grade 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 A supplementary requirement (S1) is provided for use where bond strength testing of 0.600 in. [15.24 mm] diameter Grade 270 [1860] strand for applications in prestressed ground anchors is required by the purchaser. The supplementary requirement applies only when specified in the purchase order. 1.3 The text of this specification contains notes and footnotes that provide explanatory material. These notes and footnotes (excluding those in tables) shall not be considered as requirements of the specification. 1.4 This specification is applicable for orders in either inch-pound units (as Specification A416) or in SI units (as Specification A416M). 1.5 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. 1.6 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.
ASTM A416/A416M-24 is the internationally recognized standard specification for low-relaxation, seven-wire steel strand used in the construction of prestressed concrete. Published by ASTM International, this standard details the requirements for uncoated steel strands primarily applied in pre-tensioned and post-tensioned prestressed concrete applications. Covering two grades-Grade 250 [1725] and Grade 270 [1860]-the standard ensures consistent mechanical properties, dimensional tolerances, performance, and identification for stranded steel reinforcement essential to robust, long-lasting concrete structures.
The ASTM A416/A416M-24 steel strand is integral to a variety of structural applications across civil and structural engineering sectors:
Другие стандарты ASTM
For a comprehensive approach to the specification, testing, and quality control of seven-wire steel strands, several other standards complement ASTM A416/A416M-24:
Conformance to ASTM A416/A416M-24 assures engineers, manufacturers, and contractors that seven-wire steel strands used in prestressed concrete deliver predictable performance for demanding structural applications. Adherence guarantees:
Utilizing this standard is essential for projects where strength, durability, and compliance to recognized best practices in prestressed concrete construction are critical.