Ribbed foundation for superstructures and method for producing the foundation

Abstract

The present invention relates to a reinforced-concrete foundation system for erecting superstructures that transmit high axial loads, shearing forces and/or flexural moments at individual points, such as, for example, wind turbines. The foundation that is the subject matter of the present invention is formed by an upper reinforced-concrete slab poured “in situ”, of polygonal or circular footprint, and which is made rigid at the bottom by means of reinforced-concrete ribs of rectangular or trapezial cross section which are arranged radially. The method makes provision for said ribs to be produced from concrete “in situ” or, alternatively, by means of prefabricated elements, always working, jointly with the upper slab. This new foundation considerably reduces the costs of forming traditional foundations for this type of superstructure, by considerably improving completion deadlines.

1 . Ribbed foundation for superstructures, characterized in that it is formed by an upper reinforced-concrete slab ( 1 ) having a polygonal or circular footprint and which is made rigid at the bottom by means of radial reinforced-concrete ribs ( 2 ) of a rectangular cross-section stemming from a central core ( 7 ). 
     
     
         2 . Ribbed foundation for superstructures according to the preceding claim, where the reinforced-concrete ribs ( 2 ) are of a trapezoidal cross-section and wider in the upper portion thereof in contact with the slab ( 1 ) in order to make use of excavation embankments as permanent formwork, increasing the resistant concrete section. 
     
     
         3 . Ribbed foundation for superstructures according to  claim 1  or  2 , where the reinforced-concrete ribs ( 2 ) have a constant or variable edge, either a stepped edge ( 5 ) or an edge having a constant slope, said slope decreasing as it moves away from the center of the slab ( 1 ). 
     
     
         4 . Ribbed foundation for superstructures according to any of the preceding claims, further comprising a series of piles under the stiffening ribs ( 2 ). 
     
     
         5 . Ribbed foundation for superstructures according to any of the preceding claims, further comprising columns of gravel under the stiffening ribs to improve the terrain. 
     
     
         6 . Ribbed foundation for superstructures according to any of the preceding claims, where the stiffening ribs ( 2 ) are entirely prefabricated, being provided with projecting reinforcement for connection with the slab ( 1 ) built “in situ”. 
     
     
         7 . Ribbed foundation for superstructures according to any of the preceding claims, where the stiffening ribs ( 2 ) are made by means of semi-prefabricated elements, such as double-walled parts, for example. 
     
     
         8 . Ribbed foundation for superstructures according to any of the preceding claims, where the upper concrete slab ( 1 ) comprises a first portion covering the central core ( 7 ) of the ribs ( 2 ). 
     
     
         9 . Ribbed foundation for superstructures according to  claim 8 , where the upper concrete slab ( 1 ) further comprises a perimetral ring-shaped second portion ( 6 ) separated from said first portion and connecting the outer ends of the ribs ( 2 ). 
     
     
         10 . Ribbed foundation for superstructures according to any of the preceding claims, where the central core ( 7 ) has a hollow cylinder shape. 
     
     
         11 . Method for producing the foundation for superstructures, characterized in that it comprises the steps of:
 excavating terrain to form a cavity with a shape that is complementary to the foundation element according to any one of  claims 1  to  10 .   building the reinforcement in the excavated cavity which covers the opening of the slab ( 1 ) and of the reinforcing ribs ( 2 )   pouring concrete into said cavity excavated in the terrain and in which the reinforcement has been arranged.   
     
     
         12 . Method for producing the foundation for superstructures according to  claim 11 , wherein a plurality of columns of gravel or piles are arranged in said cavity such that they are arranged below the reinforcing ribs of the foundation element.