Foundation with pedestal and ribs for towers
A foundation having a central vertical pedestal, a plurality of radial reinforcing ribs extending radially outward from the pedestal. The pedestal and ribs forming a continuous monolithic structure. An anchoring system under the ribs with anchoring the foundation to the ground by anchoring elements connected to rock anchors, soil anchors, piles or the like. The foundation design reduces the weight and volume of materials used, reduces cost, and improves heat dissipation conditions during construction by having a small ratio of concrete mass to surface area thus eliminating the risk of thermal cracking due to heat of hydration.
1. A tower foundation system comprising,
a concrete pedestal having vertical post tensioning elements therein,
a plurality of concrete ribs connected to the pedestal, the ribs extend outwardly from the pedestal and having post tensioning elements therein extending from the distal ends of the ribs through the pedestal, to compact the ribs to the pedestal under heavy post compression stress,
a ground anchoring system under each of the ribs,
at least one post tensioning element connecting the ribs to the ground anchoring system for providing compression of the ribs to the ground,
the pedestal, ribs, and ground anchoring system are connected to each other to form a rigid foundation under heavy multi-axial post compression stress.
2. A foundation as in claim 1 having,
a key on the proximal end of the ribs for connecting to the pedestal.
3. A foundation as in claim 1 wherein, the foundation includes an embedment ring near the base of the pedestal and a tower base at the top of the pedestal and having a plurality of vertical anchor bolts extending between the embedment ring and the tower base for vertical post tensioning of the foundation.
4. A foundation as in claim 1 wherein, a vertical stem is attached to the pedestal.
5. A foundation as in claim 1 wherein, the post tensioning elements extend through a rib and through the pedestal, to the opposite side of the pedestal from the rib.
6. A foundation as in claim 1 wherein, the ribs are in pairs on opposite sides of the pedestal.
7. A foundation as in claim 6 wherein, the post tensioning elements extend through a rib, the pedestal and another rib on the opposing side of the pedestal.
8. A foundation as in claim 1 wherein, at least one pedestal cage is used in the pedestal.
9. A foundation as in claim 7 wherein, the ribs have asymmetric post tensioning to provide camber to the foundation.
10. A foundation as in claim 1 wherein, the ground anchoring system has piles.
11. A foundation as in claim 1 wherein, the ground anchoring system has rock anchors.
12. A foundation as in claim 1 wherein, the ground anchoring system has soil anchors.
13. A foundation as in claim 1 wherein, the ribs have bearing elements on the top of the ribs and anchors connecting the bearing elements to the anchoring system.