PRESTRESSING STEEL

Cold-drawn high-strength wires, singly or stranded, with ultimate tensile strengths up to 270 ksi, and high-strength, alloy-steel bars, with ultimate tensile strengths up to 160 ksi, are used in prestressing. The applicable specifications are:

• ASTM A416/A416M, Uncoated Seven-Wire Stress-Relieved Strand

• ASTM A421/A421M, Uncoated Stress-Relieved Wire

• ASTM A722/A722M, Uncoated High-Strength Bar

Single strands are used for plant-made pretensioned, prestressed members. Posttensioned prestressing may be performed with the member in place, on a site fabricating area, or in a plant. Posttensioned tendons usually consist of strands or bars. Single wires, grouped into parallel-wire tendons, may also be used in posttensioned applications.