Post-tensioned structures may become damaged by corrosion, accidental impact, brittle wire cracking, or coring and drilling after construction, leading to tendon failure. The strength and serviceability of a structure that has experienced deterioration can be evaluated and restored to its original or greater strength and serviceability. PTI published guides provide an introduction to the evaluation and repair of existing post-tensioned concrete structures to familiarize owners, licensed design professionals, contractors, suppliers, and other interested parties with the procedures, tests, equipment, and other aspects of the evaluation and repair process.

External post-tensioning can be used to increase and/or restore the capacity of most any structural element.

Advantages of using post-tensioning for your next repair, rehabilitation and strengthening project:

• Structural Integrity: The strength and serviceability of a structure that has experienced deterioration can be evaluated and restored to its original or greater strength and serviceability.
• Versatility: External post-tensioning can be used to increase and/or restore, the capacity of most any structural element (beams and girders, one-way slabs, two-way slabs) made of any material (prestressed concrete, nonprestressed concrete, structural steel, wood).
• Minimal Disruption: Ability to strengthen an existing member with minimal headroom requirements and no significant added weight. Strengthening can be done with little or no disruption of existing utilities. Retrofits can typically be executed concurrently with normal building operations without any large shutdowns or closures.
• Active Loading: External post-tensioning applies active loads directly to the strengthened member so it can supplement existing capacity to any desired degree. Other strengthening systems, such as added steel, concrete beams, or FRP wrapping are passive; in the absence of jacking, the strengthened member fails to mobilize the strengthening system.