Concrete tower and climbing or self-climbing formwork device for its building onsite

A concrete tower, applicable in the installation of wind turbines, comprising a hollow sectional body of varying cross-section in the vertical direction, characterized in that it comprises:

• a lower end (11) having a general polygonal configuration formed by flat sides (12) and cylindrical portions (13) arranged between the consecutive flat sides (12);
• the flat sides (12) having a decreasing width in the upward direction throughout the tower (1), and the cylindrical portions (13) having an invariable shape throughout the tower (1);
• the tower (1) having, at its top end (11), a circular outline, consisting of the cylindrical portions (13) maintaining an invariable shape throughout the tower (1);
• and a climbing or self-climbing formwork device for building “onsite” the tower characterized in that it comprises:
• corner pieces (2a, 2b) of formwork for defining the cylindrical portions (13) of the tower;
• which pieces have an upper end (21) and a lower end (22) defining two parallel planes;
• a curved area (23) oriented longitudinally along said corner pieces (2a, 2b);
• said curved area (23) having a constant curvature radius and a straight generatrix with a predetermined slope with respect to the parallel planes defined by the upper and lower ends (21, 22) of said corner pieces;
• intermediate rectangular pieces (3), which are arranged laterally attached between the corner pieces (2a, 2b) and with the same slope as the generatrix of the corner pieces;
• said rectangular pieces (3) defining, in successive sections of formwork, flat surfaces corresponding to the flat sides (12) of the tower.
• having the corner pieces (2a), on opposite sides of the curved area (23), a respective flat extension (24) of triangular-rectangular configuration, each of said flat extensions (24) having a base and a height of dimensions matching respectively with the half of the base and with the height of the rectangular pieces (3).