Tecnica del sovracarotaggio per pilastri compressi in c.a.

The paper shows the results of an experimental investigation on the behaviour of compressed concrete columns subjected to the overcoring technique. Extraction of cylindrical concrete cores in perpendicular direction to the column surface, was achieved by rotary drilling using a diamond tipped hollow barrel. Core is gradually isolated from the stress field in the surrounding concrete and at every advancing step the re-equilibrium deformation response is measured by means of four strain-gauges, placed on its external surface and near the hole. Finally the original stress state is computed in the elastic phase on the basis of recorded strains, knowing the elastic properties of concrete and by …