While commonly referred to as prestressing rebar, the process actually involves prestressing the concrete structural member itself. Rebar (or specifically, high-strength steel strands or wires used in prestressing) is tensioned as the means to achieve this state in the concrete.
According to the provided reference, prestressing fundamentally involves:
- Putting compressive stress into the structural member.
- Doing this before it gets put into service.
How is This Achieved?
The reference clearly states the typical method for inducing this pre-service compressive stress:
- "This is normally accomplished by tensioning the reinforcement. Within the concrete."
So, the rebar (or the specialized prestressing steel reinforcement) is tensioned to apply the force needed to compress the concrete member before it bears external loads in service.
The Role of Tensioning Reinforcement
The act of tensioning the reinforcement is the crucial step that allows the concrete member to receive the desired compressive stress. Once the tension is transferred (either by bond or by anchors), the steel attempts to return to its original length, thereby compressing the concrete.
In summary, based on the reference:
Rebar (or specialized prestressing reinforcement) is tensioned as the mechanism by which compressive stress is introduced into a concrete structural member before it is used in service.
