Partially prefabricated modular foundation system

Abstract

A wind turbine foundation having a central pedestal, a bottom support slab, and a plurality of prefabricated radial reinforcing ribs. The pedestal and support slab are poured in situ at the site. When the concrete cures the support slab is united to the prefabricated ribs and the ribs are also united to the pedestal. The result is a continuous monolithic foundation wherein loads are carried across the structure vertically and laterally through the continuous structure by doweled and spliced reinforcing steel bars which are integrally cast into the pedestal, ribs and support slab. The slab thus behaves structurally as a continuous slab reducing deflections, improving fatigue conditions and increasing the stiffness of the foundation as well as allowing for the benefits of an economical design.

1 . A foundation for a tower structure which comprises:
 a prefabricated rib made of a girder with a means for receiving and continuously supporting a cast in situ slab on both sides of the girder, wherein such means insure structural continuity of the slab across the girder; and the inner end of the girder has a means for being connected to and structurally fixed into a cast in situ, tower supporting, concrete pedestal.   
   
   
       2 . A foundation for a tower structure as in  claim 1  having,
 a vertically extending pedestal cast in situ out of concrete,   a substantially horizontal support slab cast in situ out of concrete, beneath and connected to the pedestal and,   a plurality of ribs extending radially outwardly from the pedestal, the ribs integrally joined to the support slab and to the pedestal.   
   
   
       3 . A foundation for a tower structure as described in  claim 2  wherein,
 the cast in situ pedestal has an embedded anchor bolt assembly, for supporting a tower base, wherein the bolt assembly comprises an array of bond protected anchor bolts extending vertically and having one or more bearing elements at the bottom.   
   
   
       4 . A foundation for a tower structure as described in  claim 2  further comprising:
 a piling system or anchor system connected to the foundation and extending into the ground below the foundation.   
   
   
       5 . A foundation for a tower structure as described in  claim 1  wherein:
 the girder is equipped with means for receiving and connecting to at least one pile or anchor extending into the ground below the foundation.   
   
   
       6 . A foundation for a tower structure as described in  claim 2  further comprising:
 a pedestal anchor bolt assembly integral with the pedestal for connecting a tower structure thereto.   
   
   
       7 . A foundation for a tower structure as described in  claim 2  further comprising:
 an array of piers integral with the ribs with means for connecting to and supporting an array tower base element.   
   
   
       8 . A method for constructing a foundation for a tower structure which comprises:
 providing a plurality of prefabricated ribs and transporting such ribs to the site where the foundation is to be constructed;   arranging such ribs in a spaced array with the ribs being laterally spaced from one another and with inner ends and with inner ends of the ribs being adjacent a location where a tower supporting pedestal is to be formed;   providing a pedestal reinforcing cage and tower receiving components at the location where the pedestal to be formed;   providing a support slab reinforcing elements at the location where the support slab to be formed; and   pouring concrete at the site into pedestal and support slab areas to integrally join the ribs both to the slab and the pedestal after the poured concrete sets.   
   
   
       9 . A method for constructing a foundation for a tower structure as in  claim 8  further including the step of:
 prestressing the concrete vertically using a bolt assembly, in the pedestal and diagonally along the ribs and across the pedestal, and radially across the slab and circumferentially across the slab and ribs.   
   
   
       10 . A foundation for a lattice tower structure which comprises:
 a vertically extending central component that is cast in situ out of concrete;   a substantially horizontal support slab that is cast in situ out of concrete, the support slab covering an area of ground larger than that covered by the central component; and   a plurality of radial ribs extending radially outwardly from the pedestal and spaced around the pedestal, each rib being prefabricated and being joined along the base thereof to the support slab when the support slab is cast in situ and being joined along an inner side thereof to the pedestal when the pedestal is cast in situ. wherein each rib has an integrated pier that is fitted to receive and support a column of the lattice tower at the base.