(12) United States Patent
`Cody et al.
`
`(10) Patent No.:
`(45) Date of Patent:
`
`US 6,665,990 Bl
`Dec. 23, 2003
`
`I IIIII IIIIIIII Ill lllll lllll lllll lllll lllll lllll lllll lllll 111111111111111111
`US006665990B 1
`
`(54) HIGH-TENSION HIGH-COMPRESSION
`FOUNDATION FOR TOWER STRUCTURES
`
`(75)
`
`Inventors: William K. Cody, Minnetonka, MN
`(US); John R. Larson, Bloomington,
`MN (US); Jerome A. Grundtner,
`Forest Lake, MN (US)
`
`(73) Assignee: Barr Engineering Co., Minneapolis,
`MN (US)
`
`( *) Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by O days.
`
`(21) Appl. No.: 09/519,823
`
`(22) Filed:
`
`Mar. 6, 2000
`
`Int. Cl.7 .......................... E02D 27/12; E02D 27/42
`(51)
`(52) U.S. Cl. ........................ 52/295; 52/296; 52/741.15;
`405/244; 405/252.1
`(58) Field of Search ........................... 52/111, 153, 156,
`52/157, 158, 166, 169.9, 295, 296, 741.15,
`745.04, 745.17; 405/228, 244, 232, 252.1
`
`(56)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`1,164,085 A * 12/1915 Goldsborough ............. 405/244
`1,584,203 A * 5/1926 Upson .................... 405/228 X
`1,898,304 A * 2/1933 Kent ........................... 264/31
`2,741,910 A * 4/1956 Thornley ............... 52/169.9 X
`3,006,626 A * 10/1961 Lejeck et al. ................ 165/9.3
`3,364,636 A * 1/1968 Salsig, Jr ................... 52/169.9
`3,969,853 A
`7/1976 Deike et al.
`3,969,854 A
`7/1976 Deike et al.
`4,031,687 A * 6/1977 Kuntz ..................... 52/741.15
`4,590,718 A
`5/1986 Angeloff et al.
`4,650,372 A * 3/1987 Gorrell ....................... 405/232
`4,687,415 A
`8/1987 Bender et al.
`4,707,956 A * 11/1987 Sato ...................... 52/169.9 X
`4,911,581 A * 3/1990 Mauch ....................... 405/232
`4,999,966 A
`3/1991 Johnson et al.
`5,012,622 A
`5/1991 Sato et al.
`5,050,356 A
`9/1991 Johnson et al.
`5,472,311 A
`12/1995 Davis et al.
`
`5,586,417 A
`5,689,927 A
`5,722,498 A
`5,794,387 A
`5,826,387 A
`5,960,597 A
`
`12/1996 Henderson et al.
`11/1997 Knight et al.
`3/1998 Van Impe et al.
`8/1998 Crookham et al.
`10/1998 Henderson et al.
`10/1999 Schwager et al.
`
`OTHER PUBLICATIONS
`
`State of Alaska, Department of Transportation and Public
`Facilities, Report No.: FHWA-AK-RD-87-16, Use of Fins
`on Piles for Increased Tension Capacity (Spin-Fin Piles).
`Report date: Feb., 1987.
`* cited by examiner
`
`Primary Examiner-Brian E. Glessner
`(74) Attorney, Agent, or Firm-Gray, Plant, Mooty, Mooty
`& Bennett PA; Malcom D. Reid; Cecilia M. Jaisle
`
`(57)
`
`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 compo(cid:173)
`nents with their distal anchoring structure provide excep(cid:173)
`tional 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.
`
`20 Claims, 10 Drawing Sheets
`
`12
`
`Exhibit - 1005
`NV5, Inc. v. Terracon Consultants, Inc.
`Page 1
`
`

`

`U.S. Patent
`
`Dec. 23, 2003
`
`Sheet 1 of 10
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`US 6,665,990 Bl
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`12
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`16
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`16
`
`Fig.I
`
`26
`
`Exhibit - 1005
`NV5, Inc. v. Terracon Consultants, Inc.
`Page 2
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`

`

`U.S. Patent
`
`Dec. 23, 2003
`
`Sheet 2 of 10
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`US 6,665,990 Bl
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`16
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`26
`
`Fig. 2
`
`Exhibit - 1005
`NV5, Inc. v. Terracon Consultants, Inc.
`Page 3
`
`

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`U.S. Patent
`
`Dec. 23, 2003
`
`Sheet 3 of 10
`
`US 6,665,990 Bl
`
`-( -
`
`\\
`
`\ \ -
`l J -
`Fig. 3
`
`Exhibit - 1005
`NV5, Inc. v. Terracon Consultants, Inc.
`Page 4
`
`

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`U.S. Patent
`
`Dec. 23, 2003
`
`Sheet 4 of 10
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`US 6,665,990 Bl
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`Exhibit - 1005
`NV5, Inc. v. Terracon Consultants, Inc.
`Page 5
`
`

`

`U.S. Patent
`
`Dec. 23, 2003
`
`Sheet 5 of 10
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`US 6,665,990 Bl
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`26
`Fig. 5B
`
`Exhibit - 1005
`NV5, Inc. v. Terracon Consultants, Inc.
`Page 6
`
`

`

`COMPRESSION LOAD
`
`18
`
`t
`a=~
`.an..
`
`SHAFT FRICTION
`
`INITIAL SHAFT FRICTION
`
`16
`
`24 FIN SHAFT FRICTION
`EFFECTIVE Et.D BEARING
`
`J
`
`EFFECTIVE END BEARING
`FIN SHAFT FRICTION
`
`::::\
`:: ~
`
`26 I
`1-
`• 1-
`~
`"
`PILE COMPRESSION LOAD ACTION
`Fig.6
`
`26
`PILE TENSION LOAD ACTION
`
`Fig. 7
`
`d •
`r:JJ.
`•
`~
`~ .....
`~ = .....
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`e
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`a-.. a-..
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`
`~
`i,-
`
`Exhibit - 1005
`NV5, Inc. v. Terracon Consultants, Inc.
`Page 7
`
`

`

`U.S. Patent
`
`Dec. 23, 2003
`
`Sheet 7 of 10
`
`US 6,665,990 Bl
`
`34
`
`Fig.8
`
`Exhibit - 1005
`NV5, Inc. v. Terracon Consultants, Inc.
`Page 8
`
`

`

`U.S. Patent
`
`Dec. 23, 2003
`
`Sheet 8 of 10
`
`US 6,665,990 Bl
`
`• • • • • • -.,, . .
`
`• • • • • •.
`
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`
`34
`
`Fig.9
`
`Exhibit - 1005
`NV5, Inc. v. Terracon Consultants, Inc.
`Page 9
`
`

`

`U.S. Patent
`
`Dec. 23, 2003
`
`Sheet 9 of 10
`
`US 6,665,990 Bl
`
`4 . . . . .
`
`. • .•.
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`38
`
`Fig. 10
`
`Exhibit - 1005
`NV5, Inc. v. Terracon Consultants, Inc.
`Page 10
`
`

`

`U.S. Patent
`
`Dec. 23, 2003
`
`Sheet 10 of 10
`
`US 6,665,990 Bl
`
`44
`
`6
`
`Fig. 11
`
`Exhibit - 1005
`NV5, Inc. v. Terracon Consultants, Inc.
`Page 11
`
`

`

`US 6,665,990 Bl
`
`1
`HIGH-TENSION HIGH-COMPRESSION
`FOUNDATION FOR TOWER STRUCTURES
`
`FIELD OF THE INVENTION
`
`5
`
`2
`concentric corrugated cylinders, requmng extensive deep
`wide area site excavation and subsequent back filling and
`compacting. These patents require high compression of the
`anchor bolts on the poured foundations and large soil mass
`to achieve resistance to large overturning moments on the
`supported tower. The present inventive foundation answers
`a need to avoid labor-intensive deep, wide area site
`excavation, controlled replacement of soil and expensive
`fabricated steel matrix reinforcement. The inventive foun(cid:173)
`dation requires a smaller amount of concrete than conven-
`10 tional foundations, such as those described in these two
`patents.
`
`The present invention relates to the structure and method
`of installation of a deep foundation to support large
`diameter, tall towers in a wide range of soil conditions. The
`inventive foundation exhibits high tension, high compres(cid:173)
`sion and high resistance to overturning moments acting on
`the supported tower. The inventive foundation depends, on
`below ground embedded tension/compression components
`that each terminate in a distal formation of enhanced
`bearing, tension and compression capacity. The embedded
`component may be driven into position, eliminating the 15
`effort, expense and time for deep wide-area site excavations
`and dewatering. This inventive deep foundation is especially
`suitable for support of tall tubular towers, such as wind
`turbines.
`
`SUMMARY OF THE INVENTION
`An embedded high-tension, high-compression foundation
`for an above ground tower comprises a ground level cap,
`attachments for securing the tower to the cap and below(cid:173)
`ground embedded tension/compression components. The
`tension/compression components are each secured to the cap
`and each terminate distally with a below ground anchoring
`20 structure. The anchoring structure provides embedded below
`ground tension retention of the components within the deep
`level soil and/or rock mass. The components extend to deep,
`high-strength soil layers. The components are embedded
`without the need for deep wide area site excavation. The
`25 foundation of this invention requires only shallow excava(cid:173)
`tion near the surface for placement of the cap. The compo(cid:173)
`nents with their distal anchoring structure provide excep(cid:173)
`tional bearing and tension capacity, and high resistance to
`overturning moment forces acting on the supported above-
`30 ground structure.
`The cap may be steel reinforced concrete. The attach(cid:173)
`ments for securing the tower to the cap may be conventional
`anchor bolts or a flange structure for bolt attachment, such
`as a steel embedment with a circular flange plate for bolt
`35 attachment. As used herein, the terms "tension/compression
`component," "embedded component," or simply "compo(cid:173)
`nent" refer to a below ground embedded element that
`extends to a desired below ground depth and terminates in
`a distal formation contributing enhanced bearing, tension
`40 and compression capacity to the component and the sup(cid:173)
`ported above-ground structure. Non-limiting but illustrative
`examples of such components include piles with distal end
`helical fins, piles with a distal end grouted soil or rock
`anchor, piles with distal end helical soil or rock anchors,
`45 caissons with a distal belled section, caissons with a distal
`end grouted soil or rock anchor, caissons with distal end
`helical screw anchors or any combinations thereof. A pile
`with distal end helical fins is a pile with one or more fins
`welded or otherwise formed at the pile distal end in a helical
`50 or spiral configuration. Such a pile has been referred to as a
`"spin-fin pile." The distal formation contributing enhanced
`bearing, tension and compression capacity to the component
`may be preformed or may be formed in place. Thus, a
`suitable tension/compression component may be structured
`55 as follows. A pile constructed with side apertures adjacent
`the distal end of the pile is driven to its desired belowground
`position. To prevent occlusion of the pile lumen with rock
`and/or soil debris during driving, the pile may have a
`suitable closed distal end, such as a threaded or non-threaded
`60 point or auger tip. A suitable resinous fluid is introduced to
`the pile interior to permeate through the apertures and bond
`with the surrounding deep soil. If the components are
`hollow, they may then be filled, for example, with concrete.
`The components may be straight or tapered. If the compo-
`65 nents are tapered, they taper from a larger cross-sectional
`area near the soil surface to a smaller cross-sectional area at
`deep soil areas.
`
`DESCRIPTION OF RELATED ART
`
`Various installations require foundations to support tall
`large diameter tubular towers. Such installations include
`power generating wind turbines, power line towers, trans(cid:173)
`mission and communication towers, fluid tank (water)
`towers, emission stacks and similar tower structures. The
`towers are typically round, fabricated from welded plates,
`and have a horizontal circular flange plate ( or cap) for
`anchor bolt connection at the ground level base of the tower.
`The towers are generally steel, with a relatively large base
`diameter (about 8 feet or greater). The towers may be more
`than about 100 feet tall and subject to very large overturning
`moments with relatively moderate lateral loads and small
`vertical loads.
`Conventional foundations for such towers have required
`large embedments, such as large diameter piers, cylinders or
`gravity-spread foundations. Conventional foundations for
`wind turbine towers have become very large and expensive,
`as the size of the wind turbines and the height of the towers
`has increased. Conventional gravity-spread foundations may
`require a below ground maximum diameter of about 40 feet
`to bout 50 feet to support a tower pedestal of about 15 feet
`in diameter.
`Conventional gravity-spread foundations require a sub(cid:173)
`stantial below ground mass and depend, largely, on the
`vertical or lateral bearing capacity of soils near the surface.
`If the bearing capacity of the deeper soils or the weight of
`the upper level mass of soil is needed, large deep wide-area
`excavations are required. As used herein, the term "excava(cid:173)
`tion" refers to cutting and digging a large diameter cavity
`and to scooping out and removing the soil generally to the
`full depth and diameter of the hollowed-out cavity. Deeper
`larger diameter foundations spread the load of the above(cid:173)
`ground structure, but add to the cost, time and difficulty of
`installation. High groundwater can require dewatering
`operations that complicate and increase the cost of deep,
`wide area excavations for conventional gravity-spread foun(cid:173)
`dations.
`U.S. Pat. No. 5,586,417, issued Dec. 24, 1996, entitled
`Tensionless Pier Foundation and U.S. Pat. No. 5,826,387,
`issued Oct. 27, 1998, entitled Pier Foundation under High
`Unit Compression each describe large diameter below
`ground foundations of poured-on-site cementitious mono(cid:173)
`lithic construction. The foundations described in these two
`patents currently are a foundation of choice for wind turbine
`installations. The foundations of these patents use two
`
`Exhibit - 1005
`NV5, Inc. v. Terracon Consultants, Inc.
`Page 12
`
`

`

`US 6,665,990 Bl
`
`4
`FIG. 4 is a plan view of the foundation with reinforcing
`bars embedded in the concrete of the cap.
`FIGS. SA and SB show an end view and perspective view
`of the distal below ground end of a spin fin pile, showing the
`helical or spiral fins.
`FIG. 6 illustrates pile compression load action of a spin fin
`pile.
`FIG. 7 illustrates pile tension load action of a spin fin pile.
`FIG. 8 shows a cylindrical pile with a helical screw soil
`anchor.
`FIG. 9 shows a cylindrical pile with an embedded grouted
`soil or rock anchor.
`FIG. 10 shows a caisson with distal end belled section.
`FIG. 11 shows a two-sectioned fluted spin fin pile with the
`section tapered.
`
`DETAILED DESCRIPTION OF THE
`INVENTION
`
`3
`This invention is also a method of constructing an embed(cid:173)
`ded high-tension, high-compression foundation for an above
`ground tower. A minimal ground-level excavation is estab(cid:173)
`lished for the cap. Tension/compression components are
`embedded into deep, high-strength soil and/or rock layers to 5
`provide exceptional bearing and tension capacity. The distal
`anchoring means of the embedded components provide
`high-tension retention within the mass of deep, high(cid:173)
`strength soil and or rock layers. The components are embed(cid:173)
`ded by driving, angering, drilling, and the like, without the 10
`need for deep below ground wide-area excavation.
`As used herein, the term "embedding" refers to a process
`for positioning the component by locating the component at
`ground level above its desired final location and imparting
`impetus to forcibly plunge the component through the 15
`intervening soil and/or rock formations. The impetus and/or
`the shape of the component (e.g., a spin fin pile) may cause
`the component to rotate slightly while advancing to its
`desired final location. "Embedding" also refers to a process
`of positioning the component by establishing a hole in the 20
`intervening soil and/or rock formations of essentially the
`same or only slightly larger diameter than the component, so
`that the embedded component may be advanced or lowered
`into its desired final location within the hole. Alternatively,
`the component may be formed in place within the estab- 25
`lished hole. The process of establishing a hole may be by
`piercing, sinking or penetrating a hole sized to or only
`slightly larger than the component, in essentially a straight
`line. Typically, when the component is based on a pile,
`embedding may be by imparting impetus to plunge the 30
`component forcibly to its desired position. When the com(cid:173)
`ponent is based on a caisson, embedding may be by estab(cid:173)
`lishing a hole of essentially the same or only slightly larger
`diameter than the caisson and forming the caisson in place.
`The cap is then formed and the components are secured to
`the cap by any suitable method. Forming the cap may
`comprise placing formwork for the cap, including reinforce(cid:173)
`ment and means for attachment of the tower, placing con(cid:173)
`crete in the formwork, stripping the formwork, and back(cid:173)
`filling and compacting around the cap. The tower is then
`attached to the cap by any suitable method. The cap may be
`a horizontal circular flange plate. The reinforcement may be
`steel. The attachments may be anchor bolts. Spin fin piles
`and other components that are pipe piles (such as the straight
`or tapered piles with distal end helical rock or anchor screws
`and piles with a distal end grouted soil or rock anchor) may
`be embedded by driving, drilling or angering. The pipe pile
`may be driven with or without an end plate. If the tension/
`compression components are caissons, the only formation of
`a hole essentially sized to the caisson is required and the
`caisson is formed in its embedded position. Auguring or
`similar drilling methods may form a hole for formation and
`positioning of the caisson. The tension/compression com(cid:173)
`ponents may be filled, for example, with concrete. The
`tension/compression components may be battered outwardly
`from the cap and tower.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`FIG. 1 is a cross-sectional view of the tubular tower, 60
`concrete cap with anchor bolts, and spin-fin pile compo-
`nents.
`FIG. 2 is a cross-sectional view, similar to FIG. 1, in
`which a tubular tower attachment substitutes for the anchor
`bolts.
`FIG. 3 is a plan view of the tubular tower concrete cap and
`spin-fin pile.
`
`The present inventive foundation includes a ground-level
`cap and a deep below ground foundation system. The deep
`foundation of the present invention extends to deeper and
`generally higher-strength soil layers with minimal excava-
`tion and dewatering. The embedded foundation system
`provides enhanced end bearing, tension and compression
`capacity. The embedded foundation system may include
`such components as piles with distal spiral fins, a drilled
`caisson with a distal end belled section, or a driven pile or
`caisson with an embedded grouted soil or rock anchor. The
`inventive foundation is particularly adapted for supporting
`tall, large-diameter, tublar towers susceptible to high over(cid:173)
`turning moment forces, moderate lateral loads, and rela(cid:173)
`tively light vertical loads. The above ground structure sup-
`35 ported by the foundation of this invention resists 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 286,000 lbs. This type of loading commonly occurs
`with tubular wind turbine foundations having cylindrical
`40 diameters of about 8 feet, 12 feet, 24 feet or even larger and
`with tower heights ranging from about 100 feet to more than
`about 300 feet. The above ground weight of such towers may
`reach or exceed about 286,000 lbs. These towers may
`support wind turbines with a large diameter propeller at the
`45 top of the tower. The large diameter propeller may contribute
`large overturning moment forces and moderate lateral loads.
`Other tall, large-diameter tower structures with relatively
`small vertical loads may also use the inventive foundation.
`Examples of other towers supportable by the foundation of
`50 this invention include communication towers, power line
`towers, outdoor lighting, advertising, traffic control signs
`and signals, bridge supports, ski lifts, gondolas, fluid tank
`(water) towers, mission stacks and the like.
`The inventive foundation can extend to depths of from
`55 about 25 feet up to about 60 feet and even to about 100 feet.
`Deep foundations of this invention provide greater resis(cid:173)
`tance to overturning moment forces acting on the above
`ground structure. The inventive foundation exhibits excep-
`tionally high tension from about 50,000 lbs. to about 150,
`000 lbs. for each pile. The compression for this inventive
`foundation is approximately 50 percent higher than the
`tension capacity, that is, from about 75,000 lbs. to about
`225,000 lbs.
`The inventive deep foundation derives enhanced bearing,
`65 tension and compression capacity from the structure of the
`distal below ground end of the embedded foundation. Com(cid:173)
`pression resistance for any embedded foundation is typically
`
`Exhibit - 1005
`NV5, Inc. v. Terracon Consultants, Inc.
`Page 13
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`

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`US 6,665,990 Bl
`
`20
`
`5
`easier to achieve than tension resistance. An important
`characteristic of the foundation is a deep foundation with a
`high-tension capacity. With typical conventional
`foundations, there is either no tension capacity or a nominal
`tension capacity of up to about 25 percent, typically no more
`than 10 percent. A characteristic of the tension/compression
`components of the foundation of this invention is that only
`the distal below ground end of the component is constructed
`to provide retention within the terminal soil and/or rock
`mass. The construction of the distal below ground end of the
`component may be of larger size and mass than the remain(cid:173)
`der of the upper length of the component. The larger size or
`mass of the distal end of the component provides a bearing
`surface for the surrounding soils and/or rock mass. The
`construction of the distal below ground end of the compo(cid:173)
`nent may also terminate in rock or soil anchors, augers or
`screws that provide increased positive retention and fric(cid:173)
`tional resistance to pullout or overturning forces, as well as
`anchoring the component distal end into the surrounding soil
`and/or rock mass. The tension/compression components
`include piles or caissons constructed with distal terminal
`structures to increase the pullout strength of the foundation.
`The pile distal end may be constructed with helical or spiral
`fins. The caisson distal end may be constructed with a belled
`section. A grouted soil or rock anchor may be provided at the
`distal below ground end of the caisson or pile. A caisson with
`a helical screw anchor or with a grouted anchor may be used.
`Each of these distal below ground structures is engineered to
`enhance the tension capacity or bearing area and the positive
`retention and frictional resistance of the embedded founda(cid:173)
`tion. The resulting foundation benefits from the compression
`(bearing), tension, and the lateral loading capacity of the
`deep embedded foundation.
`The tension/compression components of this foundation
`install at exceptional savings of time and cost. Pile compo(cid:173)
`nents may be installed by driving. Caisson components may
`be installed by angering or drilling. The driven components
`can be battered during installation. The driven components
`are self-tested upon installation. The driven components
`displace the soil thereby increasing adjacent soil density and
`strength. The amount of energy required to drive the com(cid:173)
`ponent to its final depth determines the tension-compression
`capacity of each component. Each component can be driven
`to an individually selected depth, dependent on the soil
`and/or rock characteristics at the base of each component. It
`is not possible to judge strengths of deeply embedded soil
`and/or rock conditions accurately before foundation con(cid:173)
`struction. Also, soil strengths and/or rock conditions can
`vary across the site area. With the foundation of this
`invention, each component can be driven to an individually 50
`determined depth. The driving resistance of each component
`serves as a test that can be correlated to the component's
`axial/uplift capacity. Typically, better soils, in terms of
`supporting a foundation, exist at deeper levels. The below
`ground distal ends of the components of the present inven- 55
`tion are constructed to provide greater resistance to take
`advantage of the location of these better soils. The energy
`required to drive a component of the present inventive
`foundation is correlated to shallower penetration than that
`for the foundations described above in U.S. Pat. Nos. 60
`5,586,417 and 5,826,387 with improved pull out strength.
`Piles with helical or spiral fins at their distal below ground
`end are referred to as "spin fin piles." Spin fin piles are
`described in a State of Alaska, Department of Transportation
`and Public Facilities Report No. FHWA-AK-RD-87-16, 65
`dated February 1987. Spin fin piles demonstrate great resis(cid:173)
`tance to pull out and a large downward capacity. Spin fin
`
`6
`piles have the advantage of positioning with minimal exca(cid:173)
`vation and with a one-step driving operation. The fins of the
`spin fin piles strengthen and stiffen the distal end of the pile.
`The condition of the soil and/or rock, at the installation site
`5 determines the fin length. Typically, the less dense the soil,
`the longer the helical fins need to be, that is, the longer the
`distal end length of the pile around which the fins need to
`spiral. Generally, for purposes of this invention, about 10-25
`percent, typically about 20 percent, of the distal end length
`10 of the pile is constructed with helical fins. Installing the
`components by driving is more efficient and less expensive
`than installing other foundations that require deep, wide
`excavations. Driving densities the soil adjacent the compo(cid:173)
`nents as the components are embedded, increasing the soil
`15 strength. Other conventional foundations require artificial
`compaction of the soils to achieve the soil strength inher(cid:173)
`ently achieved by driving installation of the components of
`the inventive foundation. In many cases, recompaction of
`the existing soils with other conventional foundations is
`impractical.
`With conventional foundations, the structure of the cap
`extends much deeper into the ground and anchor bolts in the
`cap usually extend to near the bottom of the foundation.
`With the foundation of this invention, the cap, typically
`25 concrete, is located near the surface of the ground and the
`tension/compression components extend much deeper
`below ground. The components secure to the cap by attach(cid:173)
`ments such as anchor bolts. The anchor bolts for the cap of
`the present invention are much shorter than with conven-
`30 tional foundations and need not embed so deeply into the
`cap.
`The high-tension capacity, deep foundation of this inven(cid:173)
`tion uses a greatly reduced mass of concrete, in comparison
`to the mass of concrete needed in a conventional gravity-
`35 spread foundation. Typically, the inventive foundation
`requires only about one-third the volume of concrete
`required for a traditional spread foundation. The compo(cid:173)
`nents may be at least partially hollow or open-ended. Filling
`the components with concrete is optional for the inventive
`40 foundation. Filling the components with concrete adds
`strength and desirably minimizes the amount of steel in the
`foundation. Generally, only the upper portion of the com(cid:173)
`ponent (about the upper one-third) needs to be concrete
`filled to increase the bending capacity of the component near
`45 the cap. The entire length of the component may be concrete
`filled if desired.
`The inventive foundation also decreases dependence on
`the lateral bearing capacity of a large diameter pier or
`cylinder, used in conventional foundations, eliminating the
`need for a large mass of concrete or for deep excavations.
`The benefit of the present inventive foundation system, in
`comparison to other systems, increases as the magnitude and
`proportion of overturning moment of the supported above
`ground structure increases. As wind turbine technology
`continues to advance to higher capacity wind turbines on
`taller towers, the need for and benefits of the high-tension
`high compression foundation of this invention will continue
`to increase.
`The present invention encompasses a wide range of
`embodiments of the high-tension, compression deep foun(cid:173)
`dation. A presently preferred embodiment uses the "spinfin"
`pile embedded foundation system for a wide range of soil
`conditions. FIGS. 1, 2 SA and SB illustrate spin fin piles 16
`for the foundations of this invention. Spin fin piles 16 are
`constructed with spiral or helical fins 24 at their distal below
`ground ends 26. A spin-fin wind turbine foundation 10 of
`this invention, as seen in FIG. 1, supports a wind turbine
`
`Exhibit - 1005
`NV5, Inc. v. Terracon Consultants, Inc.
`Page 14
`
`

`

`US 6,665,990 Bl
`
`7
`tower 12 and other, similar support towers. This foundation
`10 can generally be described as a pile foundation with a
`concrete cap 14 for attachment of the above ground tower 12
`and below ground tension/compression components. In FIG.
`1, the components are spin fin piles 16. To install the 5
`foundation 10 shown in FIG. 1, a shallow excavation 18 in
`the surface soil 20 is formed for placement of the cap 14.
`The desired number and arrangement of spin fin piles 16 are
`driven into position battered radially outward from the cap
`14 and supported tower 12. If required for a particular 10
`installation, the piles 16 may be concrete filled. Formwork
`(not shown) is placed for the cap 14. Attachments, such as
`anchor bolts 22, for the tower 12 are positioned in the
`formwork. FIG. 2, a cross-sectional view of the foundation
`10 similar to FIG. 1, shows a tubular tower attachment 28 15
`that substitutes for the anchor bolts 22. The fins 24 are
`helically welded steel plates located on the distal lower
`portion of straight or tapered pipe piles 16, which may have
`a round or other cross-section. Where the pipe piles 16 are
`tapered, they taper from a larger cross-sectional area near the
`soil surface to a smaller cross-sectional area at deep soils.
`Piles 16 are typically of steel. The addition of helical or
`screw-type fins 24 to the piles 16 significantly increases the
`ultimate compression and tension capacity of the piles 16.
`FIG. 3 is a plan view of the foundation 10 with the spin 25
`fin pile 16, the tower 12, and the cap 14. If required for a
`particular installation, reinforcement for the cap 14 may be
`added to the formwork, as illustrated in FIG. 4. FIG. 4 is a
`plan view of the foundation 10 with circular reinforcing bars
`30 embedded in the concrete of the cap 14 and a center
`reinforcement bar mat 32. Concrete is positioned in the
`formwork and allowed to set. The formwork is stripped and
`soil 20 is backfilled and compacted around the cap 14.
`FIGS. SA and SB show an end view and perspective view
`of the distal below ground end of a spin fin pile 16, showing
`the helical or spiral fins 24. FIG. 6 illustrates pile compres(cid:173)
`sion load action of a spin fin pile 16, as in driving the pile
`16 into embedded position. During the compressive loading
`of driving the spin fin pile 16, shaft friction acts in an upward
`direction along the pile shaft above the spin fins 24 ( as 40
`indicated in FIG. 6 by the upward arrows along the pile
`shaft). Effective end bearing of the spin fin pile 16 is exerted
`on the soil mass below the spin fins 24. Fin shaft friction acts
`in an upward direction on the spin fins 24 (as indicated by
`the upward arrows along the fins in FIG. 6). FIG. 7 illustrates 45
`pile tension load action of a spin fin pile 16, as in resisting
`forces on the above ground tower 12, acting to dislodge the
`spin fin pile 16 from its embedded position. During the
`tension loading acting on the spin fin pile 16 from the forces
`against the supported tower 12, initial shaft friction acts in 50
`a downward direction along the pile shaft above the spin fins
`24. FIG. 7 indicates this by the downward arrows along the
`pile shaft. Effective end bearing of the spin fin pile 16 is
`exerted on the soil mass above the spin fins 24. Fin shaft
`friction acts in a downward direction on the spin fins 24 ( as 55
`indicated by the downward arrows along the fins in FIG. 7).
`FIG. 8 shows a foundatio