Support structure for a wind turbine and procedure to erect the support structure

Abstract

The invention comprises a series of spans of column shaft ( 1 ) with a frustoconical shape, each span integrating two or more parts ( 2 ) and ( 3 ) with a polygonal or circular section formed with pieces prestressed in a bed in the factory, with centered or slightly deviated prestressing ( 4 ) and non-prestressed reinforcement ( 5 ) in the perimeter of the section or fibers, attached by means of wet or dry longitudinal joints ( 6 ), rotated in plan view or not, and transverse joints ( 7 ) which can be at different levels and provide continuity or not to the general prestressing, for a joining by means of steel bars ( 12 ), and in the case of the attachment to the foundation with direct positioning of the starter bars at the time said foundation is built, or by means of jacket tubes which will subsequently receive the mentioned bars ( 16 ).

1 - 16 . (canceled) 
     
     
         17 . A support structure for wind turbines, of the type comprising a column shaft ( 1 ) partially formed by two or more superimposed annular structural sections attached to each other by transverse joints ( 7 ), each of the mentioned structural sections integrating at least two prefabricated concrete wall pieces ( 2 ,  3 ), with a polygonal or circular fraction cross-section, arranged adjacently, attached by longitudinal joints, characterized in that
 each of the mentioned wall pieces is obtained by prestressing in the factory, precompressing its body in a manufacturing bed, by means of at least several stressed cables extending throughout it, such that a predetermined prestressing is incorporated in the piece from its manufacture and acts as a resistant reinforcement, said prestressing in the factory being calculated according to the relative position that the wall piece is to occupy in the support structure;   each of said wall pieces is assembled with the adjacent ones in superimposition to form the support structure, with an attachment established only at its opposing ends facing and without an additional post-tensioning affecting the entire wall piece; and   the wall pieces of one or more of said annular sections have in one or two of their end portions a thickened section in which ducts are configured for arranging therethrough spans of prestressing cables.   
     
     
         18 . The support structure according to  claim 17 , characterized in that the mentioned thickened section comprises configurations with an increasing thickness from one end of the piece to the outlet area of the duct and extends throughout a longitudinal span for a length between 50 and 300 cm. 
     
     
         19 . The support structure according to  claim 18 , characterized in that the mentioned thickened section projects inwardly, outwardly or towards both inner and outer faces of the annular section of the wall piece, offering in the most prominent area a surface for anchoring the post-tensioning of a cable. 
     
     
         20 . The support structure according to  claim 17 , characterized in that the mentioned thickened section encompasses a complete annular section or fraction of annular section of the wall piece. 
     
     
         21 . The support structure according to  claim 17 , characterized in that in some of said wall pieces the prestressing cables used for precompression of the piece are extended through spans, projecting out of the wall piece, said extension spans being provided for being inserted through said ducts configured in an adjacent wall piece, for linking thereto through a subsequent tensioning of said cable extension spans, obtaining a transverse joint which assures the continuity of the prestressing, as two superimposed wall pieces are arranged with their ends facing. 
     
     
         22 . The support structure according to  claim 17 , characterized in that the mentioned ducts for the passage of the projecting cables for subsequent tensioning are provided with jacket tubes. 
     
     
         23 . The support structure according to  claim 17 , characterized in that each annular structural section comprises at least two wall pieces ( 2 ) and ( 3 ) with polygonal or semicircular cross-section of a thin wall with a centered prestressing ( 4 ), or slightly deviated with respect to the thickness of the piece or with a non-uniform distribution throughout the annular section to correct the effects of its own weight or other temporary loads, and a non-prestressed reinforcement ( 5 ) in the perimeter of the section, the wall pieces ( 2 , 3 ) being attached to each other by means of transverse and longitudinal joints ( 6 ). 
     
     
         24 . The support structure according to  claim 17 , characterized in that each of the wall pieces ( 2 ,  3 ) is frustoconical or cylindrical, and in that the wall pieces of the different annular sections attached by transverse joints ( 7 ) have different heights. 
     
     
         25 . The support structure according to  claim 17 , characterized in that it further comprises one or more cables or bars arranged through projecting portions, with greater thickness, of the ends of each wall piece. 
     
     
         26 . The support structure according to  claim 17 , characterized in that it is built with a material selected from: high-strength concrete, self-compacting concrete or fiber concrete. 
     
     
         27 . The support structure according to  claim 23 , characterized in that the attachments of the longitudinal joints ( 6 ) are carried out by means of perforated concrete flanges ( 10 ), along the inside of the longitudinal edges of the piece, which allow closing of the joint by means of screw bolts and nuts ( 11 ), controlling the tightening torque. 
     
     
         28 . The support structure according to  claim 23 , characterized in that the mentioned longitudinal joints ( 6 ) of the different annular structural sections are displaced in the rotating direction for the purpose of preventing a continuous longitudinal joint along the different spans of the column shaft. 
     
     
         29 . The support structure according to  claim 24 , characterized in that the attachment of the transverse joints ( 7 ) to both the foundation and between spans is provided, where appropriate, by means of a collar-like thickening ( 13 ) at the ends of each wall piece, perforated in the direction of the generatrix of the piece such that it allows the joining by means of high-strength steel bars ( 12 ) which will be post-tensioned on site at the time of assembly and with sufficient length to assure the continuity of the prestressing in all the sections of the tower, despite the loss of prestress in the anchoring areas of the strands. 
     
     
         30 . The support structure according to  claim 24 , characterized in that the intercalated starting pieces ( 2 ) and ( 3 ) and the intercalated top ones of the tower have a different height, preferably half the length, the transverse attachments ( 7 ) between pieces of the successive spans or column shafts ( 1 ), at different levels, allowing the assembly of the tower without the need for auxiliary assembly structures or elements. 
     
     
         31 . A process for erecting a support structure according to  claim 17 , characterized in that it comprises the one-by-one installation of each wall piece ( 2 ,  3 ), and the linking of a wall piece ( 2 ,  3 ) to another contiguous one forming longitudinal joints, at one and the same level or transverse joints in superimposed arrangement.