Post-tensioned cables use greased strands; the strand count is seven.

• A. Seven-strand
• B. Five-strand
• C. Nine-strand
• D. Eight-strand

Answer: (A)

Post-tensioned cables use a seven-wire strand as the standard element. Each tendon is comprised of greased, seven-wire strands because this configuration provides the right balance of tensile strength, ductility, and flexibility to run through ducts and be tensioned effectively. The seven-wire arrangement (one central wire with six around it) also allows grout to fill and bond around the strands after tensioning, transferring the prestress into the concrete. While other strand counts exist in various applications, the seven-wire strand is the conventional choice for post-tensioning, which is why the strand count is seven.