What is primarily transferred to the concrete in post-tensioning?

In post-tensioning, the primary force that is transferred to the concrete is the prestressing force. This is achieved through the use of high-strength steel tendons or cables that are tensioned after the concrete has been cast and has gained sufficient strength.

When these tendons are tensioned, they create a compressive force in the concrete, counteracting the tensile forces that will be applied to the structure from loads once it is in service. The process of post-tensioning involves anchoring the tendons at the ends of the concrete member after they have been stretched, which in turn transfers that prestressing force into the concrete. This results in improved performance characteristics, such as increased load-carrying capacity, reduced deflections, and control over cracking.

Understanding that the prestressing force is what enhances the structural integrity of the concrete is key to using post-tensioning effectively in design. This process is essential for constructing elements like beams, slabs, and bridges, where reducing tensile stress in concrete members is critical for durability and serviceability.