According to PCI and AASHTO specifications, the maximum jacking force applied to a strand should not exceed what percentage of its ultimate strength?

The correct answer is 80% because PCI (Precast/Prestressed Concrete Institute) and AASHTO (American Association of State Highway and Transportation Officials) guidelines are established to ensure the safety and integrity of structures using prestressed concrete. To avoid material failure or unnecessary stress that could compromise the overall performance of the prestressed strands, these organizations recommend that the maximum jacking force applied to a strand be limited to 80% of its ultimate strength. This threshold helps to maintain a safety margin, ensuring that the strands can withstand additional loads encountered in service without risk of rupture or other failures, promoting durability and longevity in infrastructure projects.