El ensayo de despegue y las bandas de tolerancia de la fuerza de pretensado en edificios de contención de centrales nucleares

The loftoff test and the tolerance band of prestressing force in concrete containment structures

In this paper, a short description of the actual situation in the inservice inspection of ungrouted tendons in prstressed concrete containment structures accodring to the U.S. Nuclear Regulatory Commission is presented. Emphasis is made in gaps and cagheness existing in inservice inspection, mainly from a mechanical point of view, some of those in reference with the liftoff test. In relation with this test, the main sources of error to determinate the prestressing force either in project or during the inservice inspection are analyzed. Finally, a probabilistic treatment to define the tolerance band to use as approval or rebound criterium in the liftoff test is presented. This treatment is shown with a numerical example.