U.S. patent application number 16/904030 was filed with the patent office on 2020-12-17 for screw anchor foundations and related interfaces for modular, manufactured and prefabricated structures.
The applicant listed for this patent is Ojjo, Inc.. Invention is credited to Tyrus Hudson, David Mar, David Warner, Jack West.
Application Number | 20200392688 16/904030 |
Document ID | / |
Family ID | 1000004928489 |
Filed Date | 2020-12-17 |
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United States Patent
Application |
20200392688 |
Kind Code |
A1 |
Mar; David ; et al. |
December 17, 2020 |
SCREW ANCHOR FOUNDATIONS AND RELATED INTERFACES FOR MODULAR,
MANUFACTURED AND PREFABRICATED STRUCTURES
Abstract
A foundation system for manufactured homes, prefabricated
houses, and other structures. Multiple screw anchors are driven
into the ground at the desired location of the structure. Preformed
grade bars may be placed over the screw anchors to provide a
modular foundation without pouring concrete or digging footers.
Alternatively, adapters may be attached to one or more of the
driven screw anchors to provide a pedestal to receive the grade bar
or prefabricated sections of concrete
Inventors: |
Mar; David; (Berkeley,
CA) ; Warner; David; (Fairfax, CA) ; Hudson;
Tyrus; (Petaluma, CA) ; West; Jack; (San
Rafael, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Ojjo, Inc. |
San Rafael |
CA |
US |
|
|
Family ID: |
1000004928489 |
Appl. No.: |
16/904030 |
Filed: |
June 17, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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62862624 |
Jun 17, 2019 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E02D 2300/002 20130101;
E02D 27/16 20130101; E02D 2600/30 20130101 |
International
Class: |
E02D 27/16 20060101
E02D027/16 |
Claims
1. A foundation system comprising: a first plurality of screw
anchors; and a second plurality of grade bar sections, each grade
bar section comprising an elongated concrete structure adapted at
each end to overlap with an adjacent grade bar section and to be
supported from below by at least one of the first plurality of
screw anchors.
2. The foundation system according to claim 1, wherein each screw
anchor comprises a head portion that is received in an opening
formed in one of the grade bar sections.
3. The foundation system according to claim 2, wherein a lower end
of the head portion terminates in a support having a diameter wider
than the opening.
4. The foundation system according to claim 3, wherein the head
portion is rotatable relative to the screw anchor portion to raise
and lower the support relative to the screw anchor after the grade
bar portion has been lowered over the head portion.
5. The foundation system according to claim 1, further comprising a
fastener passing through a portion of each overlapping grade bar
section to join them together.
6. The foundation system according to claim 5, further comprising
at least one anchor bolt extending above at least one of the grade
bar sections.
7. A foundation system comprising: at least one screw anchor; and
at least one pre-cast concrete section that is supported by the at
least one screw anchor at a pre-formed through-hole formed in the
pre-cast concrete section.
8. The foundation system according to claim 7, further comprising
an adapter attached to an above-ground end of the at least one
screw anchor for supporting the pre-cast concrete section at the
pre-formed through-hole.
9. The foundation system according to claim 8, further comprising
an anchor bolt for joining the adapter to the pre-cast concrete
section via the through-hole.
10. The foundation system according to claim 7, wherein the
pre-cast concrete section is a pre-cast concrete slab.
11. The foundation system according to claim 7, wherein the
pre-cast concrete section is a pre-cast grade bar.
12. The foundation system according to claim 7, wherein the at
least one screw anchor comprises an elongated hollow shaft with a
thread form at one end and head portion at an opposing end.
13. The foundation system according to claim 12, wherein the head
portion terminates at a lower end in a support having a diameter
larger than the pre-formed through-hole.
14. The foundation system according to claim 12, wherein rotation
of the head portion through the pre-cast concrete section moves the
head portion and the pre-cast concrete section relative to the
elongated hollow shaft.
15. A method of forming a foundation for a structure comprising:
driving at least one screw anchor into supporting ground on a
foundation site; and placing a pre-cast concrete section above the
at least one screw anchor so that it is supported by the at least
one screw anchor.
16. The method according to claim 15, wherein driving the at least
one screw anchor comprises driving the at least one screw anchor at
a predetermined position to support portion of a pre-cast concrete
slab.
17. The method according to claim 16, wherein placing the pre-cast
concrete section above the at least one screw anchor comprises
placing the pre-cast concrete slab on an adapter connected to the
at least one screw anchor so that the adapter is aligned with a
through-hole formed in the slab.
18. The method according to claim 15, wherein driving the at least
one screw anchor comprises driving at least one screw anchor at a
predetermined position to support a portion of a pre-cast grade bar
foundation section.
19. The method according to claim 18, wherein placing the pre-cast
concrete section above the at least one screw anchor comprises
placing the pre-cast grade bar section on the at least one screw
anchor so that a head of the least one screw anchor is received in
opening formed in the pre-cast grade bar section.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This claims priority to provisional patent application No.
62/862,624 titled "Universal foundations, precast slabs and related
interfaces for modular and prefabricated construction projects,"
filed Jun. 17, 2019, the disclosure of which is hereby incorporated
by reference in its entirety.
BACKGROUND
[0002] There are many advantages to modular and prefabricated home
construction relative to building homes onsite. For one, modular
and prefabricated homes are often built indoors in
climate-controlled factories rather than exposed to the elements.
This keeps the materials dry as well as protecting them from theft
and vandalism. It also avoids weather-related construction delays.
Centralizing construction at one factory simplifies allows building
materials to be delivered to a single location rather than to
distributed jobsites. In addition, building inside a factory allows
the use of jigs, templates, and computer-controlled machines, all
of which result in structures that are built with far greater
precision and consistency relative to ones that are built on-site
with hand tools. Still another advantage is that an entire
community or even a city may be constructed off-site, where ever
resources are best utilized for this purpose and then components
shipped to locations virtually anywhere in the world for final
assembly.
[0003] Modular and/or prefabricated structures do still require
some on-site work, but this work is typically limited to
site-preparation including grading, laying or running utilities and
constructing the foundation. The structures themselves are trucked
in, craned on to the foundation, and connected to the utilities and
the foundation. The process of closing seams and completing utility
hook-ups typically takes less than a week. In some cases, even
internal fixtures (e.g., plumbing and electrical) are installed at
the factory.
[0004] The most time-consuming and labor intensive of onsite
activities is typically construction of the foundation. After the
site is graded and compacted, the soil is excavated to make room
for the foundation. In some cases, a continuous trench footer is
dug around the entire outline of the structure. Rebar and wire are
placed in the trench then it is filled with concrete. Anchor bolts
are inserted into the drying concrete or drilled and placed after
it has set, and the house is built on top of it the foundation and
anchors.
[0005] In other cases, the entire footprint of the structure to be
built is scraped, leveled, and compacted. Then, concrete is poured
over the entire compacted footprint to create a slab on which the
home is built. Still further foundations use a combination of these
techniques or individual concrete pads and piers whereby individual
piles are excavated and constructed and piers are built on top of
the pile to establish a uniform building platform. Unfortunately,
there is a disconnect between the distributed, inefficient,
low-precision techniques used to construct foundations and the
highly efficient, centralized, precise techniques and process used
to build the prefabricated and/or modular structures themselves.
This can result in poor connections between structures and
foundations that result in additional on-site work to conform the
foundation and loss of time and money. Also, prefabricated
structure builders must contract with multiple regional contractors
to construct their foundations rather than simply shipping
foundation components with the rest of the modular and/or
prefabricated structure. In recognition of these problems, the
present disclosure provides foundation systems, components and
related methods that greatly simplify the process of laying a
foundation for prefabricated and modular building structures and
ideally eliminate or at least minimize non-utility-related onsite
work.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1A is a conventional strip footing foundation for a
building structure;
[0007] FIG. 1B is a cross sectional view of the strip footing
foundation of 1A;
[0008] FIG. 2A is a conventional pile and pier foundation for a
building structure;
[0009] FIG. 2B is a cross sectional view of the pile and pier
foundation of 2A;
[0010] FIG. 3A is a truss foundation according to various
embodiments of the invention;
[0011] FIG. 3B is a pre-cast slab section for prefabricated and
modular homes according to various embodiments of the
invention;
[0012] FIG. 3C is a cross sectional view of the truss interface
section of the pre-cast slab and truss foundation according to
various embodiments of the invention;
[0013] FIG. 3D is a top view of the truss interface formed in the
pre-cast slab of 3C;
[0014] FIG. 3E is a top view of the pan covering the truss
interface of 3C;
[0015] FIG. 4 is a flow chart detailing steps of a method for
installing a foundation such as that shown in FIGS. 3A-E according
to various embodiments of the invention;
[0016] FIG. 5 is a perspective view of another pre-cast slab for
prefabricated and modular structures according to various
embodiments of the invention;
[0017] FIG. 6A is a pre-cast slab and truss foundation interconnect
system according to various embodiments of the invention;
[0018] FIG. 6B is a pre-cast slab and monopile foundation
interconnect system according to various embodiments of the
invention;
[0019] FIG. 7A is another pre-cast slab and truss foundation
interconnect system according to various embodiments of the
invention;
[0020] FIG. 7B is another pre-cast slab and monopile foundation
interconnect system according to various embodiments of the
invention;
[0021] FIG. 8A is an additional pre-cast slab and truss foundation
interconnect system according to various embodiments of the
invention;
[0022] FIG. 8B is an additional pre-cast slab and monopile
foundation interconnect system according to various embodiments of
the invention;
[0023] FIG. 9A is a lift plate for lifting a pre-cast slab
according to various embodiments of the invention;
[0024] FIG. 9B is a portion of a pre-cast slab with an integrated
lift point;
[0025] FIG. 10 is a connector for joining adjacent pre-cast slabs
according to various embodiments of the invention;
[0026] FIGS. 11A and B show components of a grade block foundation
according to various embodiments of the invention; and
[0027] FIG. 12 is a flow chart detailing steps of a method for
installing a foundation such as that shown in FIGS. 11A and B
according to various embodiments of the invention.
DESCRIPTION
[0028] As discussed above, modular, and prefabricated homes offer
many advantages over on-site construction. These advantages must be
exploited to address the growing global shortage of quality,
affordable homes. However, what is missing from the modular and/or
pre-fabricated construction paradigm in a universal foundation that
allows the structure to quickly and accurately secured to the
building site regardless of soil type, without needing to excavate
and pour a custom concrete foundation. Preferably such a foundation
can be manufactured centrally and shipped with the other building
components or at least delivered to the jobsite ready to be
assembled ahead of the remaining modular and/or prefabricated
components. To that end, the applicant of this disclosure has
developed an A-frame-shaped truss foundation that is particularly
well-suited to this application. The system is known commercially
as EARTH TRUSS. The EARTH TRUSS system consists of a pair of screw
anchors that are rotated into supporting ground at angles to one
another and extended with above-ground upper legs that are joined
with an adapter to form a unitary A-frame-shaped truss
structure.
[0029] EARTH TRUSS was originally developed to support single-axis
solar trackers. When wind strikes a tracker array, large lateral
loads must be resisted by the foundation. With monopiles, these
loads impart a bending moment onto the foundation components. By
using A-frame-shaped trusses rather than monopiles, these lateral
loads are instead translated into tension and compression in the
legs. Because individual structural members are relatively good at
resist axial loads, as opposed to resisting bending, less steel may
be used to support the same size tracker.
[0030] The EARTH TRUSS relies on a specialized machine or
attachment for a general-purpose machine that uses a combination of
downward force and rotation to drive screw anchors into the earth.
These components and machines are easily adapted to construct
robust foundations for support other structures, including modular
and prefabricated homes. They can be configured as a two-legged
truss as with single-axis tracker foundations, or even as plumb
piles depending on site conditions and sheering concerns. The
present disclosure focuses on building systems and related methods
that combine EARTH TRUSS components with pre-cast concrete slab
sections to form fast, accurate, robust, and water-proof
pre-fabricated foundations that can be constructed very quickly,
shipped to the homesite as a kit, and assembled with minimal site
preparation.
[0031] To that end, the present invention will now be described in
the context of the drawing figures where like structures are
referred to with like designations. FIGS. 1A and B show
conventional strip footing foundation 10. Foundation 10 is
constructed by excavating a trench around the perimeter of the
intended structure (i.e., home, office, modular classroom, etc.),
placing rebar, wireframe forms, and/or other reinforcing structures
into the trench, and pouring concrete over them. Then concrete
blocks are used to make above-ground foundation 14 on poured
concrete footer 12. Gravel 11 may also be poured inside the walls
of foundation 14 and a concrete slab poured on top of the gravel to
create a slab such as slab 13. Anchors, ties, or other structures
15 are typically inserted into concrete block foundation 14 before
it sets to provide attachment points for the rest of the structure.
In the case of a modular or premanufactured homes, these anchors
will serve as the points of attachment. Otherwise, if the house is
built on-site, these anchors are received within wooden beams
and/or floor joists, and the home is built up from there.
[0032] FIGS. 2A and B show another conventional foundation 20
consisting of piers 24 and piles 22. In such a foundation,
individual pile portions 22 are excavated at strategic points
around a site to support load bearing portions of the structure in
accordance with a construction plan. A wood or cardboard form may
be placed around the excavated opening and wire, rebar or other
structural components placed inside before filling it with liquid
concrete. After pile 22 has set, concrete, wooden or steel piers 24
are constructed on top to form a level, elevated mounting surface
on which to set or construct the home. Piers 24 may have cap
portion 26 with integral anchor 28 that serves as the mechanical
interface between the home and foundation 20.
[0033] Though first developed hundreds if not thousands of years
ago, prior art foundations 10, 20 shown in FIGS. 1A/B and 2A/B
continue to be used today. They require substantial onsite work
with local components and labor that is completely disconnected
from the manufacturing process of the modular or prefabricated
structure that will be set on it other than knowing the necessary
foundation dimensions. As a result, even if anchors 14/28 are
positioned perfectly, something that rarely occurs, the foundation
will be the least efficient or cost-effective portion of the
project. Across a builder's or manufacturer's portfolio of
development projects there will be varying quality and varying
expense depending on many local conditions (e.g., labor rates,
material availability, weather, etc.). To overcome these problems,
the Applicant of this disclosure has proposed a system that allows
foundation components to be centrally manufactured and shipped as a
kit to the job site for rapid assembly. They may be shipped with
other modular and/or prefabricated components or shipped separately
beforehand, so that the entire structure, including the foundation,
can be assembled on-site without pouring concrete, extensive site
preparation, or excavation. FIGS. 3A and 3B show the components of
this novel foundation system according to various exemplary
embodiments of the invention.
[0034] FIG. 3A shows exemplary truss foundation 50 according to
various embodiments of the invention. Exemplary truss foundation 50
shown here consists of a pair of screw anchors 52 driven into the
ground adjacent one another and in a substantially common plane.
When used to support single-axis trackers, this plane is typically
oriented East to West, however, for supporting modular and
prefabricated homes, they may be oriented to match the orientation
of the outer walls of the structure, that is, with some trusses
oriented orthogonally or at 90-degrees relative to other
foundations to insure that any shearing forces are translated into
tension and compression as necessary. In various embodiments, and
as shown, screw anchors 52 are driven until they are almost
completely embedded into the ground.
[0035] As shown, screw anchors 52 are elongated metal tubes that
may span one to two meters with a sub-100 mm outside diameter.
External threads 53 are located at the lower end of each anchor 52
and driving couplers 54 are attached at the opposing upper end.
Driving couplers 54 may be engaged by the chuck of a rotary driver
to transfer torque and downforce to screw anchors 52 to drive them
into the ground. Couplers 54 may also provide a mechanism for
joining upper legs 55 to the end of each screw anchor 52 after the
screw anchor is driven. Upper leg sections 55 are sleeved over
respective ones of driving couplers 54 to extend the axis of each
screw anchor 52 above ground. It should be appreciated that
depending on the required height above grade, screw anchors 52 may
be used alone, that is, without needing upper legs 52. Then, an
adapter or truss cap, such as adapter 60, is used to join each
upper leg 55 (or screw anchor 52) to form a unitary A-frame-shaped
truss foundation 50. In various embodiments and as shown, adapter
60 provides support surface 62 and may include pedestal 64, with
threaded anchor bolt opening, an anchor protecting out of pedestal
64, or other structure to mechanically couple adapter 60, and by
extension, foundation 50 to the structure it will support.
[0036] FIG. 3B shows pre-cast slab section 100 that makes up part
of the foundation as well as the subfloor or base of the
prefabricated structure according to various embodiments of the
invention. In some embodiments, modular and prefabricated building
components may be set directly on top of slab 100. In other
embodiments, finished surfaces (e.g., radiant heat, tile, hardwood,
etc.) may be installed directly on top of the pre-cast slab without
needing floor trusses or a sub-floor. In various embodiments,
pre-cast slab 100 is formed in regular modular shapes (e.g.,
10-feet.times.20-feet rectangles) that can be interconnected in
common or adjacent planes to form larger structures. In other
embodiments, they may be formed in custom shapes to accommodate the
footprint of the structure. In various embodiments, pre-cast slabs
are constructed by pouring concrete into a form that has the
correct outer dimensions, is filled with re-bar and/or wire, and
that has protrusions that create through-holes or voids 108, 110,
130 at desired locations for the foundation interface, utility
connections and/or lift points. In some embodiments, conventional
concrete mixes may be used. Others may require stronger and/or more
flexible formulations to accommodate the forces of cable-based
post-tensioning.
[0037] In the example of 3B, a series of through holes 110 have
been formed in pre-cast slab 100 at points where it will be
supported by the foundations, such as, for example, foundation 50
shown in 3A. Utility through-holes 130 may be separate formed in
the center of each slap 100, or elsewhere, to allow utility hookups
(e.g., water, sewer, electricity, natural gas, etc. to pass
through). Smaller though-holes such as holes 108 may be used as
lift points to enable pre-cast sections 100 to be craned down onto
an array of foundations. Perimeter cutouts 105 may be formed around
the outside of each slab 100 at various points. Such cutouts 105
may be used to join one slab to an adjacent one. Cutouts 105 may be
also be used as lift points, obviating the need for separate holes
108. One or several of through-holes 105, 110, 130, may be
reinforced with metal or preformed metal shapes that create voids
as well as integral reinforced steel interface sections for
mechanically interfacing the slab to the truss foundations or other
structures. These shapes may be moved around within the mold before
being locked into place and numbered to specifically match the
foundation requirements of the particular site.
[0038] When manufacturing slab 100, a layer of PRECON or other
suitable material may be laid down within the form used to make
pre-cast section 100 to create a water barrier on the underside as
well as up into the utility knockouts and foundation interface
openings and lift points before the concrete is poured. PRECON is a
composite sheet membrane manufactured and sold by W.R. Meadows of
Hampshire, Ill. that forms a mechanical bond to poured concrete as
the concrete cures. It should be appreciated that other products
from other manufacturers that performs similarly may also be used.
Once the concrete has set, these pre-cast sections can be loaded
onto truck, train or into a shipping container with the truss
members and can travel as a kit to the homesite be assembled.
[0039] Turning now to FIG. 3C, this figure shows cross section
detail of one through-hole 110 for interfacing slap 100 with
foundation 50 according to various embodiments of the invention. In
this example, hole 110 consists of metal reinforced sidewalls 113
resting against walls 112. Metal reinforced sidewalls 113 may
consist of a box that sits in the mold used to create slab 100. In
the cross-sectional view of 3C, walls 112 and box 113 define a
two-sided ledge that houses slidable transfer bar 114. In various
embodiments, transfer bar 114 fits within the extended sides 112 to
allow the bar to slide along the ledge in one direction (X or Y)
in-plane (without movement in the Z-direction). This will enable
bar 114 to be easily moved to compensate for any in-plane
misalignment between the foundation through-hole 110 and adapter
60. FIG. 3D provides an overhead view of opening 110. As shown,
transfer bar 114 may preferably have one or more long slots 115
formed in it to compensate for misalignment in the other planar
direction orthogonal to the sliding direction of the bar. Slot 115
in transfer bar 114 as the bar's ability to move back in forth
within the metal reinforced opening 113 allow compensation for up
to several inches of misalignment in two direction between
through-hole 110 and adapter 60 without any impact to the integrity
of the connection. This will prevent foundation misalignment from
propagating through the building supported by slab 100. It should
be appreciated that although not shown in FIG. 3B, slab 100 may
also have a series of anchors around its perimeter that project
above the surface of slab 100 for connecting to the prefabricated
home, modular home or other structure lowered and/or built on top
of it. Such anchors can be easily placed within the mold prior to
pouring the concrete so that they are correctly located.
[0040] With continued reference to FIG. 3C, anchor bolt 116
projects up through transfer bar 114 via slot 115. In various
embodiments, a pan such as pan 120 is placed in through-hole 110
above bar 114. A nut such as nut 118 is used to secure pan 110 to
adapter 60 via bolt 116. It should be appreciated that in various
embodiments, bolt 116 may pass down from above pan 120 into adapter
60 through slot 115 in transfer bar 114. In various embodiments,
after pan 120 is secured, a layer of PRECON 122 or other suitable
material may be placed in pan 120 before filling it with concrete
124, bentonite or other suitable filler to create a water proof
seal.
[0041] FIG. 3D shows a portion of hole 110 looking down from above
with transfer bar 114 and slot 115 visible from above. This view is
consistent with the view after slab 100 has been lowered onto the
foundation. Similarly, 3E shows the same view after pan 120 has
been dropped into hole 110. As seen, pan 100 has a relatively large
opening in its bottom to permit access to the bar at different
positions.
[0042] Turning now to FIG. 4, this figure is a flow chart detailing
steps of method 160 for installing a foundation such as that shown
in FIGS. 3A-E according to various embodiments of the invention. In
various embodiments, installation begins in step 162 by installing
multiple screw anchors into the ground at the intended building
site. In various embodiments, this is done in accordance with a
plan matched to the manufacturing of the pre-cast slab(s) so that
they foundation pedestals will match up with corresponding openings
in the slab. In various embodiments, this may be accomplished by
unrolling a mat or other template that has the anchor locations
marked on it. The mat may also serve a vapor barrier and/or insect
barrier and may be staked into the ground or otherwise attached. As
discussed in greater detail herein, the screw anchors may be
installed in adjacent pairs, angled towards one another to form the
base of an A-frame-shaped truss foundation, or in other embodiments
shown herein, as plumb monopiles.
[0043] Once the screw anchors have been driven, then, in step 164,
apex hardware is installed. If necessary, this may include joining
upper legs to their respective screw anchors, depending on the
amount of above-ground elevation required for the particular site.
If the screw anchors are installed in adjacent pairs, adapters are
used to join the free end of each adjacent upper leg pair.
Alternatively, if the screw anchors are driven as plumb monopiles,
an upper leg is joined to each screw anchor, if necessary, and an
adapter is joined to the upper end of the upper leg. In either
case, in various embodiments, each adapter will include some
leveling adjustment so that the adapters can be adjusted to be
level to each other before being locked into place relative to the
legs and/or anchors. In various embodiments, and as discussed and
shown herein, the adapters may include a pedestal, anchor, or other
mechanical features to mate with and secure the pre-cast slab.
Then, in step 166, a crane is used to place one or more pre-cast
slab sections on top of the pedestals and/or adapters in accordance
with the plan. Manual manipulation of the transfer bars may be
performed as the slab is lowered to allow them to be properly
aligned with their respective pedestals as the pre-cast slab is
being lowered. This may be accomplished by simply sliding.
Alternatively, a tool may turn a cam or gear that causes the
transfer bar to slide in-plane. In various embodiments, the adapter
may have an anchor bolt or other fastener projecting above it that
engages a slot or opening in the transfer bar. Once alignment with
the respective anchors has been achieved, the entire slab may be
lowered to completely rest on the supported transfer bars which, in
turn, are resting on the foundation via the adapter and pedestal
(see, e.g., FIG. 3C).
[0044] In various embodiments, placement of the pre-cast slab
sections on the truss or monopile foundations may open up a space
between the bottom side of the transfer bars and the walls of the
steel reinforcement in the truss interface openings. In various
embodiments, in step 168, the process is completed by securing the
slab and sealing the through-holes. In various embodiments, to
accomplish this an installer may reach from the top side of the
slab to place a plug of bentonite clay in the gap between the
transfer bar and the walls to prevent water from flowing past the
transfer bar. Bentonite clay may be particular useful in this
application because it remains pliable over long periods of time
without losing its cohesion. It should be appreciated, however,
that other materials may also be used in place or in addition to
bentonite clay. For example, foam sheets or other suitable material
may be placed on the ledges below the transfer bar since these
lower ledges are not load bearing. Once the gap has been sealed, a
pan may be dropped in each truss interface opening. The pan may
have a large cutout in its bottom to account for the different
positions of the transfer bar and anchor. Also, a large retaining
nut may thread onto the anchor either before or after the pan is
set. The nut will prevent uplift and secure the slab to the
individual trusses. In various embodiments, the pan may be lined
with a sheet of PRECON or other suitable material. In various
embodiments, the anchor will be pressed through the layer of PRECON
or an opening will be cut in it to allow the bolt to pass through.
Then, a non-shrinking grout or other suitable material may be
deposited in the pan. In various embodiments, this will make the
truss interface watertight and prevent water and/or moisture from
passing through the interface and contacting structures or
components above.
[0045] It should be appreciated that in various embodiments, the
pan may be omitted, and the concrete or non-shrinking grout may be
poured directly on a layer of PRECON in the interface opening. In
sites where water ingress is not a concern, this step may be
omitted or replaced with a pest barrier to prevent bugs, termites,
and/or rodents from passing through the foundation. Also, as shown
in the FIG. 3C, the anchor bolt is shown as a static member that
projects above the adapter. It should be appreciated that the
anchor bolt may have a hexagonal or star-shaped opening in its top
surface that can receive a tool to allow rotation of the bolt. In
various embodiments, rotation may elevate or lower the pedestal
relative to the adapter and provide a mechanism for micro-leveling
the pre-cast slab after its set or to leveling the pedestal
relative to surrounding pedestals before the pre-cast slab is
set.
[0046] Turning now to FIG. 5, this figure shows pre-cast slab 200
according to various other embodiments of the invention. Instead of
the large truss interface opening in the slab of FIGS. 3B/C, such
as openings 110 in slab 100, foundation interface openings 210 in
the slab 200 shown in FIG. 5 are formed recessed and specifically
shaped to match the geometry of the pedestals supported by each
foundation. In this example, the geometry of each opening is a
tapered cuboid but it should be appreciated that other shapes,
including pyramids, posts, cuboids, cones, etc. may be used
instead. Like slab 100 shown in FIGS. 3B/C, slab 200 also includes
utility knock outs or openings 230 and several lift point openings
208. Lift point openings 208 could contain a reinforced metal
lining and bar, as shown for example, in FIG. 9B or, alternatively,
could simply be openings that receive a removable lift plate such
as lift plate 405 as shown in 9A. Also, like slab 100 of FIGS. 3B/C
slab 200 of FIG. 5 includes several coupling joints 205 around its
perimeter, which in the example, are shown as semi-circular
openings with a metal bar across them. These may be used to join
adjacent slabs to form a larger slab structure, such as, for
example, with a connector such connector 425 shown in FIG. 10. In
that case, flanges 426 will fit between the wall of the opening and
the bar of adjacent slabs 200 locking them together. Alternatively,
or in addition, these joints may be used to hang trim pieces,
pipes, conduit, or other structures, to run communication lines, or
for any other purpose. By having the foundation set back relative
to the outer edge of each slab 200, trim pieces may be hung flush
with the outer wall via joints 205. As with pre-cast slab 100 of
FIGS. 3B/C, slab 200 may also be formed with a layer of PRECON
attached to its underside that extends around the sides and up into
all the through-holes (e.g., lift points 208, utility knockouts
230, and truss interface openings 210).
[0047] The remaining figures and corresponding discussion show
interfaces that may be used to join pre-cast members to truss
foundations or monopile screw anchors according to various
exemplary embodiments of the invention. Starting with FIG. 6A, this
figure shows a portion of pre-cast slab 200 of FIG. 5 with truss
foundation 70 below it. Truss foundation 70 shown here consists of
a pair of legs extending below and above ground that are angled
towards one another and joined with adapter 74. In this example,
support plate 77 sits on top surface 75 of the adapter 74. Support
plate 77 may have a pair of holes 78 or other suitable features to
enable it to be securely attached to adapter 74. Plate 77 may also
have integral pedestal 79 formed on top surface. In various
embodiments, pedestal 79 is attached to the plate so that it can
move or pivot around the surface of the plate at different
positions to enable it to be matched to the position of the
corresponding void in the interface opening of the slab to
compensate for any misalignment when placing slab 200.
Alternatively, interface opening 210 may also be able to rotate or
slide in-plane in a manner similar to the transfer bar shown in 3C
so that each opening may be positioned to be directly above at and
at the correct rotational orientation to receive one of the
pedestals. For example, as shown in the cutaway view of 6A, the
interface opening 210 may actually be constructed of a plate
captured within the opening that can slide in X and Y directions
and/or rotate in-plane to enable it to be oriented precisely so
that opening 211 is directly above pedestal 79.
[0048] In the example of 6A, washer 212 sits above interface
opening 210 after slab 200 has been lowered on to pedestals 79 to
create a flat surface. An anchor bolt such as bolt 213 may pass
down from above through washer 212 and into a threaded opening in
the top surface of pedestal 79. Alternatively, pedestal 79 may
contain an anchor protruding up above it. In such embodiments,
anchor bolt 213 shown in 6A will be replaced with a retaining nut.
Such modifications are within the spirit and scope of the
invention. Though not shown, after slab 200 has been secured with
the anchor bolt or other fastener, opening 210 containing the bolt
and washer may be filled with non-shrinking grout or other suitable
material to create a uniform, water resistant upper surface to slab
200.
[0049] FIG. 6B shows a slab and foundation interface like that of
5A but the truss foundation 70 has been replaced with a single,
plumb-oriented monopile foundation 80. In various embodiments,
monopile foundation 80 consists of a single screw anchor 82 driven
substantially plumb into the supporting ground with an upper leg
attached thereto, if necessary. Then, adapter 84, similar to
adapter 74 shown in 6A is set on top of anchor or leg 82 and the
remaining connections occur in the same manner as in the context of
6A with the same modifications possible.
[0050] Turning now to FIGS. 7A and B, these figures show another
exemplary interface between pre-cast slab 200 and screw anchor
foundations according to various embodiments of the invention.
Pre-cast slab portion 200 is substantially the same as that shown
in FIGS. 6A and B with the same modifications possible. The
differences lie in the adapter and pedestal used to support it. In
the example of FIG. 7A, adapters 93 has a cross shape with four
anchor bolts 96 protruding upward towards slab 200. Support plate
240 is attached to adapter 93 so that anchor bolts 96 pass through
and are secured with corresponding nuts (not shown). Pedestal 244
is formed on or attached to support plate 240 with a tapered cuboid
shape. In various embodiments, cuboid pedestal 244 may be rotatable
about a pivot point around the surface of plate 240 in-plane to
enable pedestal 240 to be aligned with the corresponding cuboid
opening 231. Alternatively, foundation interface opening 210 in the
recess of slab 200 may include plate 230 that is trapped within the
slab but able to rotate and/or move in the X and Y directions
in-plane (without changing in the Z-direction) to ensure fitment
between pedestal 244 and its corresponding opening 231. In various
embodiments, washer 212 under anchor bolt 213 may be dimensioned
small enough to enable it to move around within recess 210 to
account for adjustment between each pedestal 244 and its
corresponding opening 231.
[0051] FIG. 7B shows substantially the same interface as 7A except
that truss foundation 90 has again been replaced with a plumb
monopile foundation consist of single screw anchor driven 92 at a
substantially plumb orientation. If necessary, an upper leg (not
shown) may be attached to the above-ground end of screw anchor 92.
Pre-cast slab 200 and its interface components are otherwise
identical to that shown in 7A.
[0052] Turning now to FIGS. 8A and B, these figures show yet
another simplified interface between pre-cast slab section 300 and
foundations 130, 140 respectively according to various embodiments
of the invention. Starting with 8A, the interface shown here
consists of adapter 135 with single anchor bolt 138 projecting
upward from its upper surface 137. In this exemplary embodiment,
anchor bolt 138 is received within interface opening 312 of recess
310 as slab 300 sits on adapter 135. Large washer 315 fits over
anchor bolt 138 and retaining nut 318 is attached to the head of
anchor bolt 318. Though not shown in this exemplary figure, a plate
or other force spreading structure may sit atop adapter 135 to
distribute the weight of pre-cast slab 300 over a larger surface
area. Also, as discussed herein, anchor bolt 138 may have a
hexagonal, star-shaped or other shaped opening at its head so that
inserting a tool into that opening and rotating it will elevate top
portion 137 of adapter 135 contacting the slab to raise (or lower)
the level of the slab at that interface. This may be performed
before, while, or after placing slab 300 on adapter 135. In various
embodiments, opening 312 will be much larger than the diameter of
anchor bolt 138 to compensate for any misalignment between bolt 138
and opening 312. Also, the size of recess 310 around opening 312
relative to the size of washer 315 will allow retaining nut 318 to
be attached at multiple different X-Y locations without comprising
the integrity of the connection. FIG. 8B shows a similar interface
as 8A but truss foundation 130 has again been replaced with a
single, plumb monopile foundation 140. The components above adapter
145 are substantially the same as that shown and discussed in the
context of FIG. 8A.
[0053] Turning now to FIGS. 11A and B, these figures show yet
another foundation system according to various other embodiments of
the invention. The components of system 450 include grade bar
sections 460 and screw anchor members 470. Grade bar sections 460
may be formed from concrete, reinforced concrete or other aggregate
solution that is poured into a mold and hardened. In various
embodiments, the sections are universal. In other embodiments, they
may be formed to specific dimension and numbered or otherwise
marked with indicia matching to foundation plan for the structure.
Each section 460 may include on more through-holes that enable them
to be securely connected to one another and to top end 474 of
anchors 470. In various embodiments, and as shown in 11A,
transition portion 466 of the bar may have a curved surface to
enable the next adjacent section 460 to be oriented at an angle
relative to that one so long as openings 464 on surface 462 line
up.
[0054] In various embodiments, bolt or fastener passes through
washer 472 into opening 464 is received in threaded opening 476 in
head portion 474 of screw anchor 470. The bottom side of section
460 will rest on support surface 475 to maintain level. In various
embodiments, head portion 474 may be rotatable with a socket type
tool to raise or lower head portion 474 including support 475 to
adjust the level of section 460 after it has been placed on screw
anchor 470. Also, as seen in 11B, after adjacent sections have been
joined via bolt 470 to other means, an anchor such as anchor 482
may be inserted above bolt 470 in hole 464 and then remainder of
the hole filled with grout 482 or other suitable material. In
various embodiments, opening 464 will be large enough to enable
anchor bolt 480 to be moved around to the proper orientation to
mate with the remainder of the structure to be placed on or built
above grade bars 460.
[0055] In various embodiments, grade bar sections 460 will be
designed based on the specific plans for the structure to be
erected so that anchor bolts are located at the desired locations.
Also, it should be appreciated that adjacent sections of grade bar
may be joined directly, that is, not via the ground penetrating
screw anchor. In other words, each grade bar sections may be placed
on top of one or more screw anchors but the connection between
adjacent sections may be made with hardware that only penetrate the
two overlapping sections and does not extend down into the
supporting ground below.
[0056] FIG. 12 is a flow chart detailing the steps of a method for
installing a foundation system such as that shown in FIGS. 11A and
B. Method 500 begins in step 505 where the various anchors used to
make up the foundation are installed. As discussed herein, this may
comprise rotating them into the ground with a rotary driver using a
combination of downforce and torque at precise locations indicated
in the foundation plan. The anchors may extend around the perimeter
of the structure only, or alternatively may also intermittently
pass through the middle connecting sections of the perimeter, as
necessary. In various embodiments, anchors are driven at a plumb
orientation or orthogonal to the desired placement of the grade
bars so that the height of the top end of each anchor is very
consistent relative to other anchors in the same foundation.
[0057] Next, in step 510, after all the screw anchors have been
consistent driven in accordance with the foundation plan, the grade
bars are laid down above the anchors. In various embodiments, this
is accomplished by hoisting each grade bar section with a crane and
lowering is so that at least one opening formed in the bar aligns
with the head a corresponding one of the screw anchors. The bar is
lowered until it rests on the support portion in the head of the
screw anchor. As discussed in the context of FIGS. 11A and B, it
may be possible to rotate the head of the anchor with tool to raise
or lower the support portion, thereby raising or lowering the grade
bar to be level. This process may be repeated until each grade bar
making up the foundation has been placed on the screw anchors.
[0058] Next, in step 515, each bar is secured to its adjacent bar.
As discussed above, in some embodiments, screw anchors may pass
through the grade bars at the overlap joint between each bar,
obviating the need for this step. In other embodiments, however,
separate hardware may be passed through the overlapping portions of
each adjacent bar to lock them together. Then, each opening passing
through the bars, whether to join two adjacent bars, connect the
bars to their respective screw anchors, or both, are filled with
grout or other suitable material to seal them. Joint between
adjacent bars may also be grouted and/or insulated to prevent
ingress of water, air, and insects. Then, the process is completed
in step 520 by placing anchor bolts or other tie-in structures in
the grouted openings to support the structure that will be set on
or built above the foundation.
[0059] The various foundations and pre-cast slabs shown herein will
provide a modular, transportable, precise, and easily installed
system that will rapidly increase the deployment of modular and
prefabricates homes and other structures. They will also provide a
uniform and predictable foundation that can very accurately and
consistently predict foundation costs on a per square foot basis
regardless of site conditions and with minimal pre-constructions
site preparation.
[0060] The embodiments of the present inventions are not to be
limited in scope by the specific embodiments described herein.
Indeed, various modifications of the embodiments of the present
inventions, in addition to those described herein, will be apparent
to those of ordinary skill in the art from the foregoing
description and accompanying drawings. Thus, such modifications are
intended to fall within the scope of the following appended claims.
Further, although some of the embodiments of the present invention
have been described herein in the context of a particular
implementation in a particular environment for a particular
purpose, those of ordinary skill in the art will recognize that its
usefulness is not limited thereto and that the embodiments of the
present inventions can be beneficially implemented in any number of
environments for any number of purposes. Accordingly, the claims
set forth below should be construed in view of the full breath and
spirit of the embodiments of the present inventions as disclosed
herein.
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