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`US007 618217B2
`
`c12) United States Patent
`Henderson
`
`(IO) Patent No.:
`(45) Date of Patent:
`
`US 7,618,217 B2
`Nov. 17, 2009
`
`(54) POST-TENSION PILE ANCHOR
`FOUNDATION AND METHOD THEREFOR
`
`(76)
`
`Inventor: Allan P. Henderson, 1965 Airport Dr.,
`Bakersfield, CA (US) 93308
`
`( *) Notice:
`
`Subject to any disclaimer, the term ofthis
`patent is extended or adjusted under 35
`U.S.C. 154(b) by O days.
`
`(21) Appl. No.: 11/797,772
`
`(22) Filed:
`
`May 7, 2007
`
`(65)
`
`Prior Publication Data
`
`US 2007 /0269273 Al
`
`Nov. 22, 2007
`
`Related U.S. Application Data
`
`(63) Continuation-in-part of application No. 10/734,281,
`filed on Dec. 15, 2003.
`
`(60) Provisional application No. 60/797,746, filed on May
`5, 2006.
`
`(51)
`
`Int. Cl.
`E02D 27/00
`(2006.01)
`(52) U.S. Cl. ........................... 405/255; 52/294; 52/295;
`52/296; 405/239; 405/251; 405/256
`Field of Classification Search ................ 52/223.4,
`52/294-296, 741.1, 741.14, 741.15; 405/233,
`405/236,239,249,251,256
`See application file for complete search history.
`
`(58)
`
`(56)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`1,048,993 A *
`2,162,108 A *
`2,374,624 A *
`2,706,498 A *
`2,724,261 A *
`3,186,181 A *
`3,382,680 A *
`3,559,412 A *
`3,600,865 A *
`
`12/1912 Meriwether ................. 405/253
`6/1939 Newman .................... 405/239
`4/1945 Schwendt .................. 52/223.5
`4/1955 Upson ..................... 285/290.4
`11/1955 Rensaa ........................ 52/295
`6/1965 Snow et al .................. 405/233
`5/ 1968 Takano ....................... 405/252
`2/ 1971 Fuller ......................... 405/237
`8/1971 Vanich .......................... 52/73
`
`3,793,794 A * 2/1974
`3,839,874 A * 10/1974
`3,842,608 A
`10/1974
`3,916,635 A * 11/1975
`3,963,056 A
`6/1976
`3,963,065 A
`6/1976
`4,038,827 A
`8/1977
`4,060,994 A * 12/1977
`4,217,738 A
`8/1980
`4,228,627 A
`10/1980
`4,232,846 A
`11/1980
`4,287,691 A
`9/1981
`
`................. 52/632
`Archer et al.
`Wyant ........................ 405/233
`Turzillo
`................ 405/253
`Lynch et al.
`Shibuya et al.
`Dauwalder
`Pryke
`Chitis ......................... 405/238
`Smith
`O'Neill
`Bressani
`Guenther
`
`(Continued)
`
`FOREIGN PATENT DOCUMENTS
`
`DE
`
`27 58 489
`
`11/1978
`
`(Continued)
`
`Primary Examiner-Tara Mayo-Pinnock
`(74) Attorney, Agent, or Firm-Jacobson Holman PLLC
`
`(57)
`
`ABSTRACT
`
`A post-tensioned pile anchor foundation and method therefor
`creates a void or highly compressible region between a drilled
`or driven pile anchor surrounding a post-tensioned anchor
`bolt or tendon and the bottom of a foundation cap. The void or
`compressible region can be formed by compressible spacers
`or void forming elements placed between the top of the pile
`anchor and the concrete cap. As the anchor bolt or tendon is
`post-tensioned against the cap, the void forming element is
`compressed or crushed, allowing the cap to be pulled down(cid:173)
`wardly and the pile anchor to be pulled upwardly toward the
`cap against the resistance of the surrounding soil.
`
`21 Claims, 11 Drawing Sheets
`
`Exhibit - 1012
`NV5, Inc. v. Terracon Consultants, Inc.
`Page 1
`
`

`

`US 7,618,217 B2
`Page 2
`
`U.S. PATENT DOCUMENTS
`
`10/1986 Kinnan
`4,618,287 A
`6/1989 Lin
`4,842,447 A
`3/1990 Grady, II
`4,910,940 A
`7/1992 Simpson
`5,131,790 A
`5,228,806 A
`7/1993 De Medieros, Jr. et al.
`8/1993 Angelette
`5,231,808 A
`5,289,626 A * 3/1994 Mochida et al. ............... 29/452
`5,379,563 A
`1/1995 Tinsley
`5,474,399 A * 12/1995 Chia-Hsiung ............... 405/229
`5,586,417 A
`12/1996 Henderson et al.
`5,625,988 A
`5/1997 Killick
`5,678,382 A
`10/1997 Naito
`5,761,875 A
`6/1998 Oliphant et al.
`5,826,387 A
`10/1998 Henderson et al.
`5,878,540 A
`3/1999 Morstein
`
`5,960,597 A
`6,119,425 A
`6,216,414 Bl
`6,270,308 Bl
`6,665,990 Bl *
`6,672,023 B2
`
`10/1999 Schwager
`9/2000 Shimonohara
`4/2001 Feldberg
`8/2001 Groppel
`12/2003 Cody et al.
`1/2004 Henderson
`
`................... 52/295
`
`FOREIGN PATENT DOCUMENTS
`
`FR
`FR
`JP
`JP
`JP
`JP
`JP
`
`1463696
`2030478
`55 122916
`58 166195
`59 150830
`61 233131
`6 316942
`
`3/1967
`11/1970
`9/1980
`10/1983
`8/1984
`10/1986
`11/1994
`
`* cited by examiner
`
`Exhibit - 1012
`NV5, Inc. v. Terracon Consultants, Inc.
`Page 2
`
`

`

`U.S. Patent
`
`Nov. 17, 2009
`
`Sheet 1 of 11
`
`US 7,618,217 B2
`
`FIG. 1
`
`Exhibit - 1012
`NV5, Inc. v. Terracon Consultants, Inc.
`Page 3
`
`

`

`26
`
`FIG. 2
`
`28
`
`10
`
`22
`
`40
`
`~ 12
`
`/
`
`-
`
`IV"T
`
`24
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`40
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`~ = ~
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`z 0
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`~-....J
`N
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`d r.,;_
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`
`-....l = N
`
`Exhibit - 1012
`NV5, Inc. v. Terracon Consultants, Inc.
`Page 4
`
`

`

`U.S. Patent
`
`Nov. 17, 2009
`
`Sheet 3 of 11
`
`US 7,618,217 B2
`
`FIG. 3
`
`24
`
`Exhibit - 1012
`NV5, Inc. v. Terracon Consultants, Inc.
`Page 5
`
`

`

`U.S. Patent
`
`Nov. 17, 2009
`
`Sheet 4 of 11
`
`US 7,618,217 B2
`
`FIG. 4A
`
`64
`
`55_rO
`
`°'--66
`
`60
`
`62
`
`FIG. 48
`
`66
`
`66
`
`64
`
`63
`
`Exhibit - 1012
`NV5, Inc. v. Terracon Consultants, Inc.
`Page 6
`
`

`

`U.S. Patent
`
`Nov. 17, 2009
`
`Sheet 5 of 11
`
`US 7,618,217 B2
`
`FIG. 5
`
`26
`
`Exhibit - 1012
`NV5, Inc. v. Terracon Consultants, Inc.
`Page 7
`
`

`

`U.S. Patent
`
`Nov. 17, 2009
`
`Sheet 6 of 11
`
`US 7,618,217 B2
`
`FIG. 6
`
`104
`
`82
`
`Exhibit - 1012
`NV5, Inc. v. Terracon Consultants, Inc.
`Page 8
`
`

`

`U.S. Patent
`
`Nov. 17, 2009
`
`Sheet 7 of 11
`
`US 7,618,217 B2
`
`14
`
`FIG. 7
`
`26
`
`28
`
`24
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`
`Exhibit - 1012
`NV5, Inc. v. Terracon Consultants, Inc.
`Page 9
`
`

`

`U.S. Patent
`
`Nov. 17, 2009
`
`Sheet 8 of 11
`
`US 7,618,217 B2
`
`FIG. 8
`
`26
`
`70
`
`32
`
`·~
`
`Exhibit - 1012
`NV5, Inc. v. Terracon Consultants, Inc.
`Page 10
`
`

`

`U.S. Patent
`
`Nov. 17, 2009
`
`Sheet 9 of 11
`
`US 7,618,217 B2
`
`FIG. 9
`
`26
`
`70
`
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`~ :' : .... ., ·.
`.... . : : ... ~ . . .
`..
`.
`.
`.
`
`Exhibit - 1012
`NV5, Inc. v. Terracon Consultants, Inc.
`Page 11
`
`

`

`U.S. Patent
`
`Nov. 17, 2009
`
`Sheet 10 of 11
`
`US 7,618,217 B2
`
`FIG. 10
`
`234
`
`221
`
`252
`
`212
`
`Exhibit - 1012
`NV5, Inc. v. Terracon Consultants, Inc.
`Page 12
`
`

`

`U.S. Patent
`
`Nov. 17, 2009
`
`Sheet 11 of 11
`
`US 7,618,217 B2
`
`0
`I'
`N
`
`N
`
`CD
`
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`
`Exhibit - 1012
`NV5, Inc. v. Terracon Consultants, Inc.
`Page 13
`
`

`

`US 7,618,217 B2
`
`1
`POST-TENSION PILE ANCHOR
`FOUNDATION AND METHOD THEREFOR
`
`This application claims the benefit of priority to U.S. Pro(cid:173)
`visional Patent Application No. 60/797,746 filed May 5,
`2006, and is a continuation-in-part of copending U.S. appli(cid:173)
`cation Ser. No. 10/734,281, filed Dec. 15, 2003, the subject
`matter of which is expressly incorporated herein by reference
`as if fully set forth in its entirety (hereinafter referred to as the
`'281 application").
`
`BACKGROUND OF THE INVENTION
`
`1. Field of the Invention
`The present invention is related to the field of pile anchor
`foundations and, more particularly, to a post-tensioned pile
`anchor foundation including a post-tensioned foundation cap
`and a plurality of post-tensioned pile anchors extending ver(cid:173)
`tically downward therefrom and a method of constructing
`such a post-tensioned pile anchor foundation.
`2. Description of the Related Art
`In a normal pile foundation, the piles extend to or into the
`above concrete foundation and are only compression resist(cid:173)
`ing foundation extensions. Such pile foundations are not post(cid:173)
`tensioned.
`When tall, heavy and/or large structures are constructed, a
`post-tensioned concrete foundation is desirable in order to
`provide improved rotational stiffness, minimized movement
`from dynamic forces, and increased foundation frequency to
`approach the frequency of a rigid body. Such concrete foun(cid:173)
`dations are particularly useful for the support of tall, heavy
`and/or large towers which may be used to support wind tur(cid:173)
`bines, power lines, street lighting and signals, bridge sup(cid:173)
`ports, commercial signs, freeway signs, ski lifts and the like.
`Various different forms of concrete foundations utilizing
`post-tensioned reinforcement and operational features of the
`instant invention have heretofore been disclosed in my earlier
`U.S. Pat. Nos. 5,586,417, 5,826,387 and 6,672,032, the dis(cid:173)
`closures of which are expressly incorporated herein in this
`application by reference as if fully set forth in their entirety.
`However, the concrete foundations of my aforesaid patents do
`not relate to pile anchor foundations. Therefore, a need exists
`for a pile anchor foundation that allows for the pile anchors to
`be post-tensioned.
`
`SUMMARY OF THE INVENTION
`
`The foundation of the instant invention resists supported
`structure overturn by a multitude of circumferentially spaced
`post tensioned pile anchors driven, drilled or otherwise 50
`formed into the subsurface soil. The pile anchors are con(cid:173)
`structed below a foundation concrete cap which is used to
`support a tower or other structure that is attached to the upper
`surface of the concrete cap.
`Each pile anchor includes a post-tensioning element, such
`as a tendon or bolt, that extends through a pile anchor base
`plate and the concrete cap, and then centrally into a pile hole.
`The pile hole can be formed in various ways known in the art,
`such as drilling, mandrel driving, etc. Each pile hole is filled
`with cementious material around the tendon or bolt to secure
`the pile anchors into the ground.
`The embedded portion of the tendon or bolt includes a
`lower end and an upper end. The lower end of the bolt is bare,
`i.e., is in direct contact with the cementious material, for
`bonding with the cementious material in a bottom portion of
`the pile anchor. One or more end nuts may be provided on the
`bolt lower end to facilitate bonding of the bolt lower end with
`
`2
`the cementious material. Preferably, one or more centralizers
`center the tendon or bolt in the drilled pile hole.
`The upper end of the embedded portion of the bolt is
`encased, preferably in a plastic sleeve or the like, and most
`5 preferably in a polyvinyl chloride (PVC) tube, so that the
`upper end of the bolt does not bond to the cementious material
`in the upper portion of the drilled pile hole. The sleeve also
`extends upwardly through the cap so that the tendon or bolt is
`also prevented from bonding to the cementious material of the
`10 cap. Such encased bolts in post-tensioned concrete founda(cid:173)
`tions are disclosed in my earlier aforesaid U.S. Pat. Nos.
`5,586,417 and 5,826,387.
`After the cementious material has been poured or pumped,
`such as through a hollow stemmed auger, into the drilled pile
`15 holes and allowed to cure to fix the pile anchor tendons or
`bolts in the ground, a void or space is created above the top of
`each filled pile hole or pile anchor and into the adjacent lower
`surface of the foundation cap or leveling course. One tech(cid:173)
`nique to form the requisite void or space is to insert a spacer
`20 or void forming element. The spacer or void forming element
`thus defines a hollow area between the top of each pile anchor
`and the adjacent bottom of the foundation cap. The spacer or
`void forming element is provided with an aperture, preferably
`generally cylindrical, through which the sleeved tendon or
`25 bolt extends before passing through the cap. A second tech(cid:173)
`nique would be to form a collapsible zone with a highly
`compressible material similar to Styrofoam or equivalent.
`The uppermost end of the tendon or bolt which protrudes
`from the top of the cap is fitted with the pile anchor base plate
`30 and a post-tensioning nut threaded thereon to post-tension the
`pile anchor and the concrete cap after the cementious material
`of the cap has hardened. The compressible material, spacer or
`void forming element is compressed or crushed by the post(cid:173)
`tensioning, allowing the pile anchor to pull upward until skin
`35 friction resistance with the surrounding soils equaling the
`required tendon tension is achieved. The required bolt or
`tendon tension should exceed the maximum structure uplift
`load determined for each pile anchor.
`In view of the foregoing, it is an object of the present
`40 invention to provide a concrete foundation for tall, heavy and
`large structures, such as support towers, which foundation is
`secured with post-tensioned pile anchors.
`Another object of the present invention is to provide a pile
`anchor foundation in accordance with the preceding object
`45 which includes a concrete cap positioned above the pile
`anchors and which allows the pile anchors to be pulled
`upwardly and the foundation cap pulled downwardly to
`develop soil resistance for both of the post-tensioned ele(cid:173)
`ments.
`Still another object of the present invention is to provide a
`pile anchor foundation in accordance with the preceding
`objects which includes a plurality of tendons or bolts that
`extend into each of the pile anchors with their lower end
`bonded to the pile anchor cementious material and the upper
`55 end extending through to above the top of the foundation cap,
`which upper end is free to move within the upper portion of
`the pile anchor and the foundation cap for post-tensioning.
`A further object of the present invention is to provide a
`post-tensioned pile anchor foundation in accordance with the
`60 preceding objects which includes a void or spacing defining a
`hollow area between the top of each pile anchor and the
`adjacent bottom of the foundation cap so that the top of the
`pile anchor is pulled upwardly toward the adjacent cap bot(cid:173)
`tom and the cap is pulled downwardly against the surrounding
`65 soil during the post-tensioning of each anchor tendon or bolt.
`A still further object of the present invention is to provide
`a post-tensioned pile anchor foundation in accordance with
`
`Exhibit - 1012
`NV5, Inc. v. Terracon Consultants, Inc.
`Page 14
`
`

`

`US 7,618,217 B2
`
`4
`FIG. 3 is a top plan view of the cap foundation of FIG. 1
`before concrete is poured.
`FIG. 4A is a top plan view of one embodiment of a void
`forming element for the completed cap and pile anchor foun(cid:173)
`dation of FIG. 1.
`FIG. 48 is a section view of the void forming element of
`FIG. 4A.
`FIG. 5 is a partially sectioned side view of a first step in
`forming the completed foundation with the concrete cap and
`10 pile anchors as shown in FIG. 1.
`FIG. 6 is a partially sectioned side view of a second step in
`forming the completed foundation following the first step of
`FIG. 5.
`FIG. 7 is a partially sectioned side view of a third step in
`15 forming the completed foundation following the second step
`of FIG. 6.
`FIG. 8 is a partially sectioned side view of a fourth step in
`forming the completed foundation following the third step of
`FIG. 7.
`FIG. 9 is a partially sectioned side view of an optional fifth
`step in forming the completed foundation following the
`fourth step of FIG. 8.
`FIG. 10 is a schematic perspective and partial sectional
`view, similar to FIG. 1, of a complete cap and pile anchor
`25 foundation constructed in accordance with a second embodi-
`ment of the present invention.
`FIG. 11 is a cross-sectional side view of the complete
`foundation of FIG. 10, similar to FIG. 2.
`
`3
`the preceding object in which the void or spacing is preferably
`formed by a compressible (including crushable) spacer or
`void forming element.
`Still yet anothero bj ect of the present invention is to provide
`a pile anchor foundation in accordance with the preceding 5
`objects which can be completely tested for performance and
`creep before installing the supported tower or other structure
`thereon.
`Yet a further object of the present invention is to provide a
`post-tensioned pile anchor foundation in accordance with the
`preceding objects in which the foundation may be easily and
`quickly re-leveled if partially upset by extremely high loads,
`above design loads, as a result of "Acts of God", such as
`earthquakes, tornados or hurricanes.
`Still yet anothero bj ect of the present invention is to provide
`a pile anchor foundation which has greater flexibility to
`design for supporting a wide range of towers or other struc(cid:173)
`tures, including the addition of further weight components.
`The number of pile anchors can be easily increased or
`decreased for any particular design depending upon the 20
`design capacity of the foundation, including the addition of an
`inner circle of separate post-tensioned pile anchors, if
`desired.
`A further object of the present invention is to provide a
`post-tensioned pile anchor foundation in accordance with the
`preceding objects, which can be constructed and effective in
`soils with long-term compressibility, where other founda(cid:173)
`tions are inadequate, because long-term settlement can be
`addressed in the foundation of the present invention by sim(cid:173)
`ply re-tensioning the anchor bolts periodically.
`A further object of the present invention is to provide a
`post-tensioned pile anchor foundation in accordance with the
`preceding objects which can be constructed and operate
`effectively in storm surge, flood, scour, erosion, and seismic
`zones inasmuch as the foundation of the present invention is 35
`anchored and supported deep below the surface and is able to
`be re-tensioned.
`Yet another object of the present invention is to provide a
`method for forming the post-tensioned pile anchor founda(cid:173)
`tions recited in the preceding objects.
`A final object of the present invention to be set forth herein
`is to provide a post-tensioned pile anchor foundation and
`method for construction which may be utilized in a wide
`range of soils from water-laden sand or clay formations to
`solid rock, may be formed in situ in remote locations, and will 45
`incorporate a minimum amount of concrete or other cemen(cid:173)
`tious materials, while providing at the same time a concrete
`foundation which can be maintained under heavy post-ten(cid:173)
`sion forces.
`These together with other objects and advantages which 50
`will become subsequently apparent reside in the details of
`construction and operation as more fully hereinafter
`described and claimed, reference being had to the accompa(cid:173)
`nying drawings forming a part hereof, wherein like numerals
`refer to like parts throughout. While intending to illustrate the 55
`invention, the drawings are not to scale.
`
`30
`
`DETAILED DESCRIPTION OF THE PREFERRED
`EMBODIMENTS
`
`40
`
`In describing a preferred embodiment of the invention
`illustrated in the drawings, specific terminology will be
`resorted to for the sake of clarity. However, the invention is
`not intended to be limited to the specific terms so selected,
`and it is to be understood that each specific term includes all
`technical equivalents which operate in a similar manner to
`accomplish a similar purpose.
`One embodiment of a pile anchor foundation according to
`the present invention is shown in the '281 application using
`corrugated metal pipes to define the perimeter wall of the
`anchor piles. It has been found that the pile anchors can be
`formed in various other ways known to those skilled in the art
`in order to form a post-tensioned foundation according to the
`present invention. Such further embodiments are illustrated
`and described herein.
`As shown in FIGS. 1-3, another post-tensioned pile anchor
`foundation of the present invention, generally designated by
`reference numeral 8, has a circular concrete cap, generally
`designated by reference numeral 10. The cap 10 is made of
`cementious material 46 and preferably defined by corrugated
`metal pipe 104 around its periphery and by the soil at the
`bottom 82 of an excavation in a ground surface. The soil
`underneath the cap 10 is preferably compacted to a depth of
`12 inches or more. The cap is set at or below the ground
`surface and a plurality of pile anchors, generally designated
`by the reference numeral 12 extend vertically downward into
`the soil 100 from the bottom 11 of cap 10. The pile anchors 12
`60 serve to secure the concrete cap 10 into the ground.
`The foundation cap 10 includes a series of tower anchor
`bolts 14 spaced circumferentially about the central vertical
`axis of the foundation cap. The tower anchor bolts 14 are
`preferably positioned in radial pairs forming two anchor bolt
`65 circles, generally designated by the reference numerals 16
`and 18. The inner tower anchor bolt circle 16 has a slightly
`shorter diameter than the outer tower anchor bolt circle 18.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 is a schematic perspective and partial sectional view
`of a complete cap and pile anchor foundation constructed in
`accordance with a preferred embodiment of the present
`invention.
`FIG. 2 is a cross-sectional side view of the complete foun(cid:173)
`dation of FIG. 1 showing the concrete cap positioned above
`the concrete pile anchors and the bolts or tendons extending
`therethrough in accordance with the present invention.
`
`Exhibit - 1012
`NV5, Inc. v. Terracon Consultants, Inc.
`Page 15
`
`

`

`US 7,618,217 B2
`
`5
`For example, the outer tower anchor bolt circle diameter may
`be about fourteen feet and the inner tower anchor bolt circle
`diameter may be about thirteen feet. A tower or other sup(cid:173)
`ported structure (not shown) can be attached to the concrete
`cap 10 by the tower anchor bolts 14. Structures which can be
`supported on the post-tension pile anchor foundation of the
`present invention include, but are not limited to, transmission
`towers, electrical towers, communication towers, lighting
`standards, bridge supports, commercial signs, freeway signs,
`ski lift supports, solar energy towers, wind turbine towers, 10
`large stacks or chinmeys, silos, tank structures, airport tow(cid:173)
`ers, guard towers, etc.
`The tower anchor bolts 14 extend through and are nutted
`atop a typical circular tower base flange at the bottom of the
`tower or other supported structure positioned and grouted in 15
`grout trough 23 in the cap upper surface. The other or bottom
`end of the bolts 14 extends to an embedment ring 22 near the
`bottom of the concrete cap. The tower anchor bolts 14 are
`sleeved in elongated hollow tubes 15, preferably PVC tubes,
`which cover the anchor bolts except for threaded portions at 20
`the top and bottom of the bolts. The anchor bolt sleeves
`prevent bonding of the bolts to the concrete and grout. This
`structure allows the tower anchor bolts to be elongated and
`post-stressed between the tower base flange and the embed(cid:173)
`ment ring to alleviate bolt cycling and fatigue.
`The lower ends of the tower anchor bolts 14 are anchored
`near the bottom of the concrete cap foundation with the
`embedment ring 22 with suitable nuts 102 or the like. The
`embedment ring 22 is preferably constructed of several cir(cid:173)
`cumferential segments lap jointed together. The embedment
`ring 22 is approximately the same size as and is complemen(cid:173)
`tary to the tower base flange 21. The ring 22 contains bolt
`holes for each of the tower anchor bolts. As best shown in
`FIG. 2, the tower base flange 21 is preferably seated in the
`grout trough 23.
`Reinforcing steel rebar 24 is positioned radially between
`the pairs of tower anchor bolts 14 and pile anchor bolts 26.
`The radial steel rebar is preferably in the shape of re bar hoops
`extending both near the top and the bottom of the concrete cap
`foundation 10. The rebar hoops are lapped vertically and wire
`tied near and parallel to the cap perimeter. The rebar rein(cid:173)
`forcement, which can also include welded wire mesh 28, is
`intended to resist bending forces in the concrete cap 10. Other
`types of reinforcing steel as known by those skilled in the art
`can be used for the reinforcing steel rebar 24 of the concrete
`cap 10, such as bent rebar, headed rebar, bolts and nuts, bolts
`with forged bell ends, etc.
`As shown in FIGS. 1 and 3, the pile anchors 12 are con(cid:173)
`structed below the foundation concrete cap 10. Each pile
`anchor includes an elongated pile anchor post-tensioning ele(cid:173)
`ment, preferably a bolt or tendon 26, that extends through a
`pile anchor base plate 32 on the top surface of or preferably
`grouted into the concrete cap 10, then through the concrete
`cap 10, and finally into a drilled pile hole 34 that is filled with
`pile anchor cementious material 36 to secure the pile anchors
`in the ground or soil 100.
`The embedded portion of the tendon or bolt 26 includes a
`lower end 38 and an upper end, generally designated by the
`reference numeral 40. The lower end38 of the bolt is bare, i.e.,
`is in direct contact with the cementious material 36, for bond- 60
`ing thereto when the material 36 is poured or pumped to fill
`the interior of the drilled pile holes 34. The cementious mate(cid:173)
`rial 36 preferably fills the pile holes 34 to the bottom 82 of the
`excavation area. An end nut 42 may be provided on the lower
`end of the bolt 26 (see, for example, FIGS. 5 and 6) to 65
`facilitate bonding of the bolt lowerportion38 with the cemen(cid:173)
`tious material 36.
`
`6
`The upper end 40 of the embedded portion of the bolt 26 is
`encased in an elongated hollow tube, preferably in a plastic
`sleeve 44 or the like, and most preferably by PVC tubing,
`along a major upper portion of its length, to prevent bonding
`5 with the cementious material 46 of the concrete foundation
`cap 10 and the pile anchor cementious material 36 and to
`allow for post-tension stretching. A centralizer 84 is prefer(cid:173)
`ably mounted around the lower portion 38 of the anchors 26
`so as to position the pile anchor bolt 26 centrally within the
`pile hole 34.
`As stated previously, the hollow tubes 15 and plastic sleeve
`44 for encircling or encasing the anchor bolts 14 and the
`elongated pile anchor bolts 26, respectively, are preferably
`made of PVC tubing. The plastic sleeves or tubing shield the
`bolts and prevent them from adhering to the cementious mate(cid:173)
`rial. As such, the bolts can be tensioned after the cementious
`material has hardened and cured in order to post-tension the
`pile anchors and the foundation cap of the present invention.
`Alternately, the bolts can be wrapped in plastic tape, or oth(cid:173)
`erwise sheathed, to prevent the bolts from adhering to the
`cementious material during curing and allow the bolts to
`stretch freely under tension over the entire sheathed length of
`the bolts.
`After the cementious material 36 has been poured into the
`25 drilled pile holes 34 to fix the pile anchor tendons or bolts 26
`in the ground 100, a void or highly compressible area 54 is
`formed between the top of the pile anchor cementious mate(cid:173)
`rial 36 and the adjacent lower surface 52 of the cementious
`material 46 of the concrete foundation cap 10. The void 54 is
`30 preferably formed using a compressible (including crush(cid:173)
`able) spacer or void forming element generally designated by
`the reference numeral 50, which is inserted between the top of
`each filled pile hole 34 and the adjacent lower surface 52 of
`the cap 10 to be formed. One embodiment of the void forming
`35 element 50 is representatively shown in FIGS. 4A and 48.
`The void forming element defines a void or hollow area 54
`above each pile anchor 12 and is provided with a generally
`circular aperture 56 through which the sleeved tendon or bolt
`26 extends before passing through the cap 10. The void form-
`40 ing element 50 is made to slide down the bolt 26 to sit on the
`bottom of the excavation area over the top of each filled pile
`anchor cementious material 36.
`As shown in FIGS. 4A, 48 and 5-9, the void forming
`element 50 can be a molded plastic form made of any suitable
`45 polymer material and having an upstanding peripheral wall
`60, an upper surface 62 and an open bottom 63. Alternatively,
`the void forming element 50 can be constructed as a hollow
`disc or as a compressible disc, such as a disc made of
`expanded polyurethane or of styrofoam. The element 50 can
`50 be virtually any natural or man-made material that is highly
`compressible or crushable under 10 psi pressure or greater
`and which allows the concrete cap foundation 10 to be pulled
`downwardly compressing and consolidating the underlying
`soils 100 to the required bearing strengths and allowing the
`55 pile anchors 12 to be pulled upwardly to develop the skin
`friction resistance equal to the pile anchor bolt or tendon
`post-tension.
`The void forming element 50 may also be constructed as an
`inflatable or pressurized bladder which will allow the pile
`anchor 12 to be pulled upwardly and the foundation cap 10 be
`pulled downwardly by tensioning the anchor bolts 26. As a
`further construction, the void forming element 50 can be
`made of a material that will develop great compressive
`strength when contacted with a catalyst after tensioning the
`anchor bolt or tendon. This embodiment includes materials in
`which the development of such compressive strength can be
`retarded for days.
`
`Exhibit - 1012
`NV5, Inc. v. Terracon Consultants, Inc.
`Page 16
`
`

`

`US 7,618,217 B2
`
`7
`As further shown in FIGS. 4A, 48, and 5-9, the void
`forming element 50 is preferably provided with a generally
`cylindrical coupling component 64 that defines the circular
`aperture 56 and which assists in enabling the void forming
`element to slide down the anchor bolt 26. According to one 5
`preferred embodiment, this coupling component 64 may be
`embodied as a piece of PVC pipe approximately four inches
`in diameter and two inches in length.
`According to the embodiment shown in FIGS. 4A, 48 and
`5-9, at least one and preferably two smaller generally cylin- 10
`drical tube couplers 66 may be located adjacent the coupling
`component 64. These smaller tube couplers 66 communicate
`with the hollow space 54 created by the void forming element
`50 and are each attached to a grout tube 68, one tube acting as
`an inlet and the other tube acting as an outlet. The grout tubes 15
`68 extend upwardly from the tube couplers 66 along the
`length of the sleeved bolt or tendon 26 to its uppermost end.
`Following post-tensioning, grout or other cementious mate(cid:173)
`rial may be forced into the inlet grout tube to fill any remain(cid:173)
`ing void space not eliminated by the crushing of the void 20
`form. When grout is forced through the inlet tube to the void
`space and begins to exit from the grout outlet tube, this indi(cid:173)
`cates that any remaining void space has been filled. This grout
`tube construction is optional, however, and is not necessary to
`the effectiveness of the present invention.
`The uppermost end of the tendon or bolt 26 which pro(cid:173)
`trudes from the top of the cap 10 is fitted with a pile anchor
`base plate 32 and a post-tensioning nut 70 is threaded onto the
`tendon or bolt to post-tension the pile anchor 12 and the
`concrete cap 10 after the cementious material 46 of the cap 30
`has hardened. The void created by the void forming element
`50 is compressed and element 50 is crushed by the post(cid:173)
`tensioning, allowing the pile anchor 12 to pull upwardly until
`skin friction resistance with the surrounding soils equaling
`the required tendon tension is achieved. The required bolt or 35
`tendon tension exceeds the maximum structure uplift load
`determined for each pile anchor.
`The steps undertaken to form the completed foundation of
`FIG. 1 can be described with reference to FIGS. 5-9 as fol(cid:173)
`lows. As shown in FIG. 5, first an area 80 is excavated having
`a depth generally corresponding with the intended thickness
`of the cap 10 and leveling course. Representatively, this area
`80 has a depth of about 4 feet. Within the excavation area 80
`and starting from the bottom 82 thereof, a plurality of spaced
`pile holes 34 are drilled or driven. These pile holes 34 typi- 45
`cally have a diameter of about 18-36 inches and a depth from
`about 30 feet to about 50 feet. In the representation illustrated
`in the drawings, the pile holes are 24 inches in diameter and
`40 feet deep, and twenty pile holes 34 are formed. After the
`pile holes 34 are formed, pile anchor bolts or tendons 26 are 50
`inserted therein. The pile anchor bolts or t