Mono-strand (Bonded)

Mono-strand bonded post-tensioning is a prestressing technique that utilizes a single high-strength steel strand to introduce compressive forces into concrete structures. The strand is anchored at both ends and tensioned, creating a controlled stress within the concrete.

• Strand: A single high-strength steel strand is used as the prestressing element and is typically coated to provide corrosion resistance.
• Duct: The strand is inserted into a protective duct, usually made of corrugated metal or plastic. Depending on the application the ducts will be placed at a parabolic profile for standard spans, harped for point loads such as columns coming down for levels above, and in some cases both.
• Anchorage: The strand is anchored at both ends of the structure using specialized devices that can withstand the high tensile forces.
• Tensioning: After the strand is anchored, it is tensioned using hydraulic jacks. Single strand jacks can be handled by one or two people in lieu of multistrand rams that require crane time. This process introduces compressive forces into the concrete, improving its structural performance.
• Grouting: Once the strand is tensioned, grout is injected into the duct to create a bond between the strand and the surrounding concrete. This bond helps transfer the prestressing force to the concrete, enhancing its strength and durability. Much smaller grout machines can be used compared to ones used with multistrand.