Additional post-tensioning consists of adding external forces to modify the stress condition of an existing structure so that it can be restored to its original working capacity, increase its load bearing capacity and/or improve the serviceability performance, cracking and deflection.
This technique can be used on bridges, circular structures such as water towers and silos, building slabs and beams. Additional post-tensioning can be performed using Freyssinet’s strand or bar systems.
X Range Anchorages
Freyssinet has developed the X Range anchorage system for the active strengthening of circular structures. These anchorages use external post-tensioning hoop tendons to apply a radial pressure onto the structure being strengthened. They are suitable for all circular structures, such as silos, tanks, chimneys, cooling towers, pipes and old brickwork.
R Range Anchorages
The 1R15 anchorage is an external prestressing mono-strand anchorage designed for the strengthening of existing structures, especially for concrete beams or pier headstocks and girders. The longitudinal prestressing force of the strand is transferred to the structure by the friction between the 1R15 anchorage and the surface of the structure. This friction is created by stressing a clamping bar through the structure or sealed in a blind hole. An epoxy resin is applied at the interface between the anchorage and the concrete to enhance the friction.