High-tension high-compression foundation for tower structures

• US 6,665,990 B1
• Filed: 03/06/2000
• Issued: 12/23/2003
• Est. Priority Date: 03/06/2000
• Status: Expired due to Fees

• Current Assignee: Barr Engineering Co.
• Original Assignee: Barr Engineering Co.
• Inventors: Grundtner, Jerome A., Cody, William K., Larson, John R.
• Primary Examiner(s): Glessner, Brian E.
• Application Number:
  US09/519,823
• Time in Patent Office: 1,387 Days
• Field of Search: 521/11, 521/53, 521/56, 521/57, 521/58, 521/66, 521/699, 522/95, 522/96, 527/411.5, 527/450.4, 527/451.7, 405/228, 405/244, 405/232, 405/252.1
• US Class Current: 52/295
• CPC Class Codes: E02D 27/42 Foundations for poles, masts or chimneys sockets or holders for poles or masts per se E04H12/22

Abstract

An above ground tower foundation uses embedded tension/compression components secured to a ground level cap. The components each terminate distally in a below ground soil or rock anchoring structure. The components embed without deep wide area site excavation or dewatering. The components with their distal anchoring structure provide exceptional bearing and tension capacity to the foundation, and high resistance to overturning moments acting on the tower. The tension/compression components may be straight or tapered piles with distal end helical fins, piles with a distal end grouted soil or rock anchor, caissons with a distal belled section, caissons with a distal end grouted soil or rock anchor, helical screw anchors or any combinations thereof

Construction of this foundation comprises the following steps. A minimal ground-level excavation is established for the cap. The tension/compression components embed into deep, high-strength soil layers without deep below ground excavation. The cap is formed. The components are secured to the cap. The tower attaches to the cap. Preferred tension/compression components are spin-fin piles—a pile with a helical fin at the distal pile end. The tension/compression components may be battered outwardly from the cap and tower.

Claims

1. An embedded high-tension, high-compression foundation for an above ground tower comprising:

a ground level cap for supporting the tower;

attachments to secure the tower to the cap; and

embedded tension/compression components secured to the cap and terminating only distally with a bearing surface resistant to pullout and overturning forces to provide embedded tension retention of the components within a terminal soil/rock mass;

wherein the components extend to deep, high-strength soil layers in absence of deep wide-area excavation to provide exceptional bearing and tension capacity, high resistance to overturning moment forces acting on the tower, and compression significantly higher than the tension capacity.

2. A foundation according to claim 1, wherein the components are selected from piles with distal end helical fins, piles with a distal end grouted soil or rock anchor, piles with a distal end helical screw anchor, caissons with a distal belled section, caissons with a distal end grouted soil or rock anchor, caissons with a distal end helical screw anchor, and combinations thereof.

3. A foundation according to claim 1, wherein the components are concrete filled.

4. A foundation according to claim 1, wherein the components are battered outwardly from the cap and tower.

5. A foundation according to claim 1, which exhibits tension of from about 50,000 lbs. to about 150,000 lbs. for each component.

6. A foundation according to claim 1, which exhibits compression about 50% higher than tension capacity.

7. A foundation according to claim 1, which supports an above ground structure resistant to overturning moment forces of greater than 20,000,000 lb./ft., lateral loads of more than 110,000 lbs., and vertical loads of more than 280,000 lbs.

8. A method of constructing an embedded high-tension, high-compression foundation for an above ground tower comprising:

establishing a minimal ground-level excavation for a cap;

embedding below ground level tension/compression components that terminate only distally in a bearing surface to provide below ground tension retention within a terminal soil/rock mass absent deep wide area excavation, so that the components extend to deep, high-strength soil layers to provide exceptional bearing and tension capacity, high resistance to pullout and overturning forces, and compression significantly higher than the tension capacity

forming the cap; and

securing the cap to the components.

9. A method according to claim 8, wherein the tension/compression components are selected from piles with a distal end helical fin, piles with a distal end grouted soil or rock anchor, piles with a distal end helical screw anchor, caissons with a distal belled section, caissons with a distal end grouted soil or rock anchor, caissons with a distal end helical screw anchor, and combinations thereof.

10. A method according to claim 8, including filling the tension/compression components with concrete.

11. A method according to claim 8, including battering the components outward from the cap and tower during embedding.

12. A method according to claim 8, wherein embedding comprises positioning the component at ground level and imparting impetus to plunge the component through intervening soil/rock to its desired final location.

13. A method according to claim 8, wherein embedding comprises establishing a hole in intervening soil/rock of dimensions essentially equal to a desired final location of a component and positioning the component within the hole.

14. An embedded high-tension, high-compression foundation for an above ground tower comprising:

a ground level cap for supporting the tower;

attachment means for attaching the tower to the cap; and

embedded tension/compression components secured to the cap and terminating distally with anchoring means to provide below ground tension embedded retention of the components within a terminal soil mass;

wherein the components extend to deep, high-strength soil layers in absence of excavation for embedding of the components to provide exceptional bearing and tension capacity, high resistance to overturning moment forces acting on the tower.

15. A foundation according to claim 14, wherein the components are selected from piles with distal end helical fins, piles with a distal end grouted soil or rock anchor, piles with a distal end helical screw anchor, caissons with a distal belled section, caissons with a distal end grouted soil or rock anchor, caissons with a distal end helical screw anchor, and combinations thereof.

16. A foundation according to claim 14, wherein the components are concrete filled.

17. A foundation according to claim 14, wherein the components are battered outwardly from the cap and tower.

18. A method of constructing an embedded high-tension, high-compression foundation for an above ground tower comprising:

establishing a minimal ground-level excavation for a cap;

embedding below ground level tension/compression components that terminate distally in an anchoring means to provide below ground tension retention within a terminal soil mass in absence of deep below-ground excavation, and extending the components to deep, high-strength soil layers to provide exceptional bearing and tension capacity;

forming the cap; and

securing the cap to the components.

19. A method according to claim 18, wherein the tension/compression components are selected from piles with a distal end helical fin, piles with a distal end grouted soil or rock anchor, piles with a distal end helical screw anchor, caissons with a distal belled section, caissons with a distal end grouted soil or rock anchor, caissons with a distal end helical screw anchor, and combinations thereof.

20. An embedded high-tension, high-compression foundation for an above ground tower comprising:

a ground level cap for supporting the tower;

attachments to secure the tower to the cap; and

embedded tension/compression components secured to the cap which are spin fin piles;

wherein the spin fin piles extend to deep, high-strength soil layers in absence of deep wide-area excavation to provide exceptional bearing and tension capacity, high resistance to overturning moment forces acting on the tower, and compression significantly higher that the tension capacity.