Design and installation practices provide high reliability in PTA systems. Features of these practices include:
- Design
- High factors-of-safety in required bond length.
- Site investigations are carried out in order to characterize a site; particularly the bond zone.
- Additionally, the ground-water at the site must be analyzed to determine its chemical properties. The analytical results reveal the potential corrosive power of the groundwater so that mitigation steps may be taken.
- Manufacturing
Factory mill certifications are required to ensure wire strengths are achieved
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- Installation
- Pilot holes are drilled before boring the entire cavity for the PTA tendon. The alignment and location are confirmed through this test, and then the final holes are drilled.
- Material strengths are tested on site to ensure the materials meet design requirements (e.g. the grout). Also, the strands are tensioned to 80% of the guaranteed ultimate tensile strength (GUTS).
- Testing
- The test equipment is calibrated prior to use.
- Lift-off tests are performed to confirm the tension in the tendons and the strength of the tendons themselves.
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