1. Adding forces through additional prestressing reinforcement and/or imposed deformations

1.1 Context

Prestressing is the application of forces of known intensity, at well-defined points and in well-defined directions, capable of opposing the forces generating the disorders. It is said to be "additional" when applied to existing structures to restore or increase their load-bearing capacity or extend their service life.

• Additional prestressing is generally external. Only in the case of short or very short prestressings (active stirrups), or prestressings designed from the outset to be installed in specific recesses, can additional prestressing be placed inside the concrete itself. As a general rule, its application requires prior treatment of any cracks by injection with a rigid product, as it cannot close cracks on its own....