U.S. patent application number 16/704963 was filed with the patent office on 2020-07-16 for building structure and method.
The applicant listed for this patent is Mark E. WILSEY. Invention is credited to Mark E. WILSEY.
Application Number | 20200224448 16/704963 |
Document ID | / |
Family ID | 46543076 |
Filed Date | 2020-07-16 |
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United States Patent
Application |
20200224448 |
Kind Code |
A1 |
WILSEY; Mark E. |
July 16, 2020 |
BUILDING STRUCTURE AND METHOD
Abstract
A load bearing structure including a first fixed net layer, a
second fixed net layer and a non-linear structure in between. The
first fixed net layer may include a first layer of flexible,
drapable fabric and a fixing material that fixes the shape of the
first layer of flexible, drapable fabric. The second fixed net
layer may include a second layer of flexible, drapable fabric and a
fixing material that fixes the shape of the second layer of
flexible, drapable fabric. The non-linear reinforcing structure may
be in communication with the first and second fixed net layers and
may be configured to share with the first and second fixed net
layers a load applied to the load bearing structure.
Inventors: |
WILSEY; Mark E.; (Pagosa
Springs, CO) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
WILSEY; Mark E. |
Pagosa Springs |
CO |
US |
|
|
Family ID: |
46543076 |
Appl. No.: |
16/704963 |
Filed: |
December 5, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14448342 |
Jul 31, 2014 |
10533339 |
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16704963 |
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13436123 |
Mar 30, 2012 |
8813433 |
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14448342 |
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13337885 |
Dec 27, 2011 |
8627612 |
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13436123 |
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11309015 |
Jun 8, 2006 |
8104233 |
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13337885 |
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60595139 |
Jun 8, 2005 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E04B 2001/0061 20130101;
E04C 5/07 20130101; E04H 9/00 20130101; E04H 15/34 20130101; E04B
7/12 20130101; E04B 2/845 20130101; E04H 15/54 20130101; E04B 7/08
20130101; E04B 1/161 20130101 |
International
Class: |
E04H 15/54 20060101
E04H015/54; E04B 7/12 20060101 E04B007/12; E04C 5/07 20060101
E04C005/07; E04B 7/08 20060101 E04B007/08; E04H 9/00 20060101
E04H009/00; E04H 15/34 20060101 E04H015/34 |
Claims
1. A method of forming a building structure, comprising: providing
a first layer of flexible, drapable fabric comprising tensile load
bearing fibers over a framework comprising spaced-apart supports;
deploying in situ the first layer of flexible, drapable fabric into
a first preselected shape; applying in situ a fixing material to
the first layer of flexible, drapable fabric to fix the shape of
the first flexible fabric, wherein applying the in situ fixing
material to the first preselected shape results in a first
self-supporting shell that is structurally adapted to hold the
first preselected shape and to bear both applied tensile and
applied compressive loading sufficient for the shell to be a
structural member as a mold or finished assembly.
Description
CROSS REFERENCE TO RELATED PATENT APPLICATION
[0001] This application is a Divisional of U.S. patent application
Ser. No. 14/448,342, filed Jul. 31, 2014, which is a Continuation
of U.S. patent application Ser. No. 13/436,123, now U.S. Pat. No.
8,813,433, filed Mar. 30, 2012, which is a Continuation-in-part of
U.S. patent application Ser. No. 13/337,885, now U.S. Pat. No.
8,627,612, filed Dec. 27, 2011, which is a Continuation of U.S.
patent application Ser. No. 11/309,015, now U.S. Pat. No.
8,104,233, filed Jun. 8, 2006, which claims the benefit of U.S.
Provisional Application No. 60/595,139, filed Jun. 8, 2005, all of
which are incorporated herein by reference in their entirety.
FIELD
[0002] The present invention generally relates to structures such
as buildings, load bearing shapes or components thereof. More
specifically the invention relates to in situ fabrication of one or
more load bearing shapes utilizing minimally supported tensile load
bearing net combined with compressive load bearing hardening or
fixing material that is separated by a non-linear reinforcing bar
that provides depth of member for the assembly.
BACKGROUND
Description of Related Art Including Information Disclosed Under 37
CFR 1.97 and 1.98
[0003] Construction methods for conventional housing and commercial
buildings often employ wood framed walls covered by external
sheathing and an outer finish layer of masonry, stucco, wood
siding, shingles, or the like. These methods and structures are
costly and time-consuming.
[0004] High and rising construction costs contribute to economic
inflation. High and increasing rents contribute to a reduced
standard of living for many people. High construction prices
exclude many people from home ownership. High rents for office
space contribute to the failure of small business.
[0005] U.S. Pat. No. 5,566,521 provides a strong and durable
structure and method for constructing buildings. However, still
more rapid building systems are desirable.
[0006] It would be desirable to produce buildings of all
descriptions by new methods that enable rapid erection at lower
cost than conventional methods.
[0007] Further, it would be desirable to fabricate building
structures in situ, using locally available materials that may be
wastes or recycled materials of potentially very low cost.
[0008] In addition, it would be desirable to have available a
method of building structures that is changeable on site, by merely
altering the shape or placement of a fabric that is minimally
supported.
[0009] To achieve the foregoing and other objects and in accordance
with the purpose of the present invention, as embodied and broadly
described herein, the method and structure of this invention may
comprise the following.
SUMMARY
[0010] An embodiment relates to a load bearing structure including
a first fixed net layer, a second fixed net layer and a non-linear
structure in between. The first fixed net layer may include a first
layer of flexible, drapable fabric and a fixing material that fixes
the shape of the first layer of flexible, drapable fabric. The
second fixed net layer may include a second layer of flexible,
drapable fabric and a fixing material that fixes the shape of the
second layer of flexible, drapable fabric. The non-linear
reinforcing structure may be in communication with the first and
second fixed net layers and may be configured to share with the
first and second fixed net layers a load applied to the load
bearing structure.
[0011] An embodiment provides a building structure and method for
constructing a building in a substantially shorter time than
typical by prior, conventional methods, using low cost, readily
available materials, especially indigenous materials.
[0012] Another embodiment provides a structure and method of
construction that replaces traditional or conventional internal
post and beam structural configuration with a more economically
attractive alternative. In particular, the alternative construction
provides an exoskeleton or external structural element. Exoskeleton
construction is the most efficient type of construction. The
alternative construction may include a post and beam, an
exoskeleton skin without post and beam, or both.
[0013] Another embodiment enables the use of indigenous materials
when and where practical, both for convenience and cost
savings.
[0014] Another embodiment provides a method of constructing a
building that allows one of the structural parts of an exoskeleton
to be fabricated on-site and first utilized as a mold, second
utilized as one or more of two structural skins, and third utilized
as a finished coating.
[0015] The accompanying drawings, which are incorporated in and
form a part of the specification, illustrate preferred embodiments
of the present invention, and together with the description, serve
to explain the principles of the invention. In the drawings:
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is an isometric view of a building at a preliminary
stage of construction.
[0017] FIG. 2 is an isometric view of a building shell at a
subsequent stage of construction, employing alternating offset post
members.
[0018] FIG. 3 is an isometric view of an embodiment of a roof.
[0019] FIG. 4 is an isometric view of another embodiment of a
roof.
[0020] FIG. 5 is an isometric view of a curved roof segment.
[0021] FIG. 6 is an isometric view of an inverted curved roof
segment.
[0022] FIG. 7 is an isometric view of a vault shaped roof
segment.
[0023] FIG. 8 is an isometric view of the roof of FIG. 3 during a
step of construction.
[0024] FIG. 9 is an isometric view of the roof of FIG. 3 during a
further step of construction.
[0025] FIG. 10 is an isometric assembly view showing layers of any
component of building construction.
[0026] FIG. 11 is an isometric assembly view showing layers of any
component of alternate building construction.
[0027] FIG. 12 is a horizontal cross-sectional plan view of a first
embodiment of shell section structure.
[0028] FIG. 13 is a horizontal cross-sectional view of a second
embodiment of shell section structure.
[0029] FIG. 14 is a horizontal cross-sectional view of a third
embodiment of shell section structure.
[0030] FIG. 15 is a horizontal cross-sectional view of a fourth
embodiment of shell section structure.
[0031] FIG. 16 is a horizontal cross-sectional view of a fifth
embodiment of shell section structure.
[0032] FIG. 17 is a horizontal cross-sectional view of a sixth
embodiment of shell section structure.
[0033] FIG. 18 is an isometric view of a building with radiating
roof supports.
[0034] FIG. 19 is an isometric view of a basalt filament structure,
showing deformations increasing grip.
[0035] FIG. 20 is a cross section illustrating of a non-linear
reinforcing bar according to an embodiment.
[0036] FIG. 21 is a table providing a comparison of embodiments of
the invention with select conventional building materials.
DETAILED DESCRIPTION
[0037] The various embodiments described below relate to building
structures and methods for constructing a structurally sound
building potentially in a reduced time and potentially at a reduced
cost as compared to prior conventional practices. The building
structure is constructed as an exoskeleton. For purposes of
defining such a building structure, an exoskeleton employs three
features: an inner structural skin or shell, an outer structural
skin or shell, and an intermediate filler layer having the function
of spacing apart the inner and outer shells in order to increase
depth of member or moment of inertia. The invention refers to a
building structure, which encompasses all parts of a building, such
as roof, floor, walls, and finish coatings. Components such as wall
or roof will be described individually in order to disclose
preferred structure, but the teachings of any component are
applicable to all other components and entire building structures.
The method and resulting structure are best understood by reference
to the drawings.
[0038] Prior methods of construction in which a fixative was
applied to a flexible fabric required a mold or formwork to support
liquid or plastic hardening materials. This limitation is costly in
both materials and labor. In the previous patent (U.S. Pat. No.
8,104,233) from which this application claims priority, the first
fixed layer does not require a supplementary or auxiliary mold.
Only minimal support is used depending on the desired
configuration. As will be discussed in more detail below, the
instant application provides instructions to further minimize and
even eliminate the need for supports.
[0039] Prior methods that use fixed nets disclose that layers of
hardened fabrics or nets are stacked, or layered, one upon another.
The shapes of the additional stacked layers are substantially
dictated and defined by the original mold layer shape. Thus, the
layers must be substantially identical to one another and in full
contact with one another. In contrast, as disclosed in U.S. Pat.
No. 8,104,233 and discussed in more detail below, there are many
different efficient load bearing shapes. As one example, a folded
plate comprising a fixed tensile net may be utilized as a spacer
between fixed layers to provide depth of beam or member between the
exterior surface layers. However, the inventor has discovered a
more effective way of producing these advantageous shapes where a
tensile load bearing fabric material is not necessary in the
intermediate core area to separate one exterior layer from the
other. Instead, the more efficient non-linear spacing bar is used
to replace the tensile load bearing net or expanded materials.
[0040] The net fiber materials are chosen to bear tensile loads
applied to the fixed layer(s). Further, the hardening or fixing
materials are chosen to bear compressive loads applied to the fixed
layer(s). However, net fiber materials and hardening or fixing
materials that support both tensile and compressive loads may be
chosen. Within the context of this application, the words
self-supporting, load bearing, structural, and reinforcement relate
to the capacity to resist loads applied pursuant to structural
engineering principles and protocols. Further terminologies used
herein are defined by those skilled in the art of structural
engineering. Specifically, such terms as depth of beam or member,
moment of inertia and other words of art apply to the shapes and
the spaces, or air, defined by the combination of the non-linear
reinforcing bar in assembly with the outer exterior coatings. The
term in-situ means monolithically formed in place, such as cast in
place, and assembled in place, i.e. on site. In-situ includes
forming in the position of ultimate use, such as forming the wall
of a building. In-situ also includes forming on-site but not in the
ultimate position, such as forming a roof portion adjacent to the
building which is later put in place on the building.
[0041] According to the invention, a building shell or envelope is
formed of a net layer that is carried by any necessary supports. A
hardening layer is applied to fix the shape of the net layer and to
establish wall, roof, and floor sections, which if desired are
formulated to be of sufficient strength to be a finished assembly.
If required, especially to accommodate changes of plan, the
hardened net may serve as an in situ mold for receiving application
of further layers. Building sections can be generally flat or can
be arranged in shapes selected from parallel-sided segments and
converging-sided segments, with troughed or domed section shapes,
and combinations of these. A building structure can be formed of
shell sides and central spacer or filler layer. Optionally, posts
or beams support the walls, roof, and floor sections and can be
formed integrally of net and hardener layers.
[0042] The structure of the building shell provides a first
self-supporting component layer that is structurally adapted to
bear both tensile and compressive loading applied. The first layer
is formed of fabric treated with fixable material. A second
self-supporting component layer is spaced from said first component
layer by an intermediate layer. The second layer is structurally
adapted to bear both tensile and compressive loading and is formed
of a tensile element treated with fixable material. The
intermediate component layer occupies the space between the first
and second component layers and establishes an exoskeleton
structure.
[0043] The tensile element of the second layer can be a structural
post. The fixable material covers the structural post, integrating
the post into the second component layer.
[0044] Alternatively, the tensile element of the second layer can
be a layer of fabric. In this variation, the second component layer
also may include a structural post that is covered or wrapped by
the layer or fabric. Both the post and fabric are treated with the
fixable material to establish an integrated structure.
[0045] Similarly, the first component layer may include a first
structural post that is covered by the fixable material; and the
second component layer may include a second structural post that is
fixed in the second component layer by a covering layer of fabric
treated with the fixable material. The first and second structural
posts can be arranged in either offset alternating positions or in
opposite juxtaposed positions.
[0046] In another variation, the first component layer includes a
first structural post that is fixed in the first component layer by
a covering layer of the fabric treated with fixable material. The
second component layer is attached to the first structural post at
a side opposite from the first component layer, such that the first
structural post establishes the thickness of the space between the
first and second component layers.
[0047] According to a method of forming a building structure, first
a framework or support is erected, suited for carrying a layer of
fabric in the general shape of the intended building or any of its
components. Next, the layer of fabric is applied over the framework
to define the building or a building component. Then, the fabric
layer is treated with a fixable material that combines with the
fabric to form a self-supporting shell structure of the building or
building component. The shell is self-supporting exclusive of the
framework, which then becomes an optional structure. Thus,
optionally the framework is removed after the self-supporting shell
has been established. Removing the framework allows the reuse of
its components and is especially useful where the framework
components are in short supply or the components are a nonrenewable
or scarce resource.
[0048] The fixable material is a hardener or coating that may
penetrate into the fabric layer before or as it hardens, forming a
first self-supporting shell. The fabric and fixable material form a
hard shell that is sufficiently self-supporting that subsequently
it can serve as a mold for application of further layers. That is,
when first layer of fabric is fixed, the result is a first
self-supporting shell that can serve as a mold for further layers
without the use of additional molds or fixtures. Thus, it is
possible to apply a second layer of fabric over the first
self-supporting shell. The second fabric layer then can be treated
with a fixable material to establish a second layer of shell. The
second layer and the fixative are fully supported by the first
fixed layer. That is, even with the addition of the weight of the
second layer of fabric and the second fixative, additional molds
and fixtures are not required. Multiple layers of shell may be
formed in series to achieve a desired strength. Also, the ability
to form multiple layers without employing a mold other than the
original layer allows the strength of a building or of any selected
building component to be increased or adjusted in the field. This
field adjustment requires no waiting for availability and delivery
of additional structural components such as larger trusses, as
would be required in conventional building practice.
[0049] The building method contemplates that an exoskeleton
structure will be desirable for most building structures. In order
to achieve an exoskeleton structure, an intermediate spacer layer
is applied--to the first self-supporting shell. Then a second layer
of fabric is applied--contiguous to or attached to the intermediate
layer. The second fabric layer is treated with fixable material to
establish a second layer of shell structure over the intermediate
layer, thereby creating in situ the exoskeleton structure. Thus,
the ability to mold one layer to another allows the efficient
formation of an exoskeleton having opposite structural skins
separated by an intermediate layer of selected and variable
thickness.
[0050] Recognizing that a fabric or net layer might be difficult to
work with in high winds or due to other ambient difficulties, it is
possible to overcome such a problem by pretreating the fabric to
stiffen it. After the fabric has been applied to a framework or
mold surface, it may be treated by applying a thin, fast acting
surface coat of hardening agent or penetrating agent that stiffens
fibers of the fabric layer.
[0051] In certain structures and building types, it may be
desirable to modify the characteristics of an exoskeleton or shell
by the addition of structural members such as posts or beams. This
modification can be implemented by forming the first
self-supporting shell and then applying structural supporting
members to the shell. In a specific application of this concept, a
roof section can be fabricated by erecting a framework of at least
two upper roof supports in an at least partially spaced apart
orientation. The fabric layer is applied to this framework and
treated with fixing agent. If the fabric layer is applied in
tension between the supports, the result is a flat roof section. If
the fabric layer is applied in loose or draped configuration
between the supports, the result is a troughed or catenary curved
roof section. The step of applying the fixing layer to the fabric
both hardens the fabric into a shell and may incorporate the roof
supports into the shell.
[0052] In a variation of the method, the upper roof supports are
supported at a preselected level, and the troughed portion of the
draped fabric extends below the preselected level. Then, before
fixing agent is applied, a lower roof support is applied to the
troughed portion of the fabric below the preselected level. The
lower roof support tensions the fabric between upper and lower roof
supports, establishing a shell having a folded plate structure.
Both upper and lower supports can be incorporated into the
shell.
[0053] In another variation of roof structure, a fabric layer is
draped between roof supports in troughed configuration. Treating
the fabric with fixable material establishes a self-supporting,
troughed roof shell structure. The troughed roof shell structure is
inverted to form a vaulted roof structure.
[0054] In FIG. 1, a temporary, re-usable, framework 30 defines or
holds the shape of a draped layer of net, scrim, or fabric 32. The
quantity of wood needed for a residential structure is expected to
be less than one-hundredth of the amount used for conventional
construction. For convenience of description and not as a
limitation, layer 32 interchangeably will be termed a "net" or
"fabric." In a main or principal treatment, the net is treated or
coated with a substantial layer of material that itself assumes a
fixed or permanent shape or, preferably, in combination with the
net causes the net and coating as a combined entity to assume a
fixed or permanent shape. The fabric 32 and principal coating form
a structural shell of the building or building component. The
treated net may be described as being hardened or frozen in a
permanent shape.
[0055] In this context, "frozen" refers to establishment of a
permanent or fixed shape and does not necessarily require or imply
the use of cold temperatures. The treating or coating will be
referred to as a fixable material or fixing agent, which indicates
that the material itself or the material in combination with the
net layer in due course forms a structure that is self-supporting,
for example by the fixable agent hardening or drying. This
definition accommodates a possible cure time, drying time, or the
like, if any, in order for the fixed or permanent shape to be
achieved.
[0056] For purposes of this invention, preferred netting materials
include rock fibers, particularly basalt fibers, to form structural
nets or scrims. These preferred choices perform particularly well
as compared to known construction netting, scrim, cloths, and
lathe. However, known scrims of various other materials can be
used. Known materials include plastics, polymers, other synthetics,
fiberglass, metals, and alloys. Polymers can have a reinforced core
or may be of the type referred to as fiber reinforced polymers.
Examples of fibers added to a polymer are glass, carbon,
polypropylene, and like materials. Examples of synthetics include
high-density polyethylene, low-density polyethylene, nylon,
polypropylene, and like materials. Examples of metals and alloys of
metals include steel and aluminum.
[0057] The use of basalt fiber in netting and in other elements of
the building structure produces improved performance and
environmental advantage. This type of fiber is produced from a
substantially unlimited resource, as basalt or similar rock that
composes roughly 90% of the earth's crust. Basalt fibers previously
have lacked sufficient grip to function properly in concrete mix
designs or as a scrim for receiving a concrete coating. As used
here, the term `grip` refers to the ability of a deformed
reinforcing bar to resist any movement or slippage when encased
with concrete.
[0058] Basalt filaments or fibers are produced by heating basalt to
a melting or plastic temperature, and the molten material is then
extruded through bushings. In further processing at a forehearth,
the filaments are next combined or woven into the final product and
sized, typically by addition of a plastic or polymer coating. Final
products might be a strand useful in forming netting or fabric, or
strands can be combined to form a reinforcing bar similar to steel
rebar. FIG. 19 shows an elongated element 80 that might be a fabric
strand, reinforcing bar, or other product formed of basalt fibers
or filaments.
[0059] In order to create a fiber with improved grip, the basalt
material can be deformed while being processed from hard rock, to
molten rock, to malleable rock, and back to cooled hard filament.
The deformations 82, FIG. 19, can be surface deformations similar
to the surface ribs utilized on steel reinforcing bar. However, in
a preferred processing step for maintaining an optimum ratio of
strength to material quantity, the deformations 82 should not be
configured out of additional material, such as the ribs added to
typical steel reinforcing bar. Thus, in a preferred embodiment the
deformations 82 are flattened segments of the basalt filament. This
method of increasing grip allows the basalt filaments 80 to remain
in a parallel configuration, which is the preferred alignment for
the filaments to bear tensile loads.
[0060] Alternate method of increasing grip may be utilized.
Filaments can be deformed, such as by kinking, bending, or forming
into loops. Deformed filaments are suitable for use in rebar, in
scrim or net, or as chopped fiber. The addition of a sizing or
coating may sufficiently increase grip characteristics as necessary
to meet structural testing standards.
[0061] Used as netting, rebar, or chopped fiber, the improved
basalt fibers or filaments are significantly stronger than other
commonly used reinforcements. Basalt fibers are almost ten times
stronger than grade forty steel reinforcement. Compared to the cost
of producing steel rebar, production savings are almost thirty
percent. Compared to the cost of producing carbon fiber, basalt
fiber costs about one tenth as much; with the added benefit that
basalt fiber yields ninety percent of the strength per pound of
carbon fiber technology. Thus, strength, production economies,
reduction of fossil fuel consumption for production and
transportation, all provide improved characteristics of this
material whether as a core fiber, such as in fiber reinforced
polymers, or standing alone as a reinforcing element.
[0062] Known scrims of polymer and plastic are flexible in varying
degrees. Flexibility has been acceptable for typical usage such as
structural reinforcement. Various known applications for
reinforcement are stucco, plaster, structural concrete, earth for
erosion control, and structural stabilization under roads. Thus,
known netting is useful as a means of holding or maintaining
material in some specific kind of discipline. Most are sold and
transported in rolls exhibiting this characteristic. As well, most
steel and aluminum scrims and stucco netting are in rolls, although
some types of metal lath are supplied in flat pieces or sheets.
However, even these sheets are flexible in one direction and may be
flexible in both directions. These net materials have not been
required to be frozen into static, hard, inflexible shape.
[0063] As an optional pretreatment before applying a principal
coating or hardening layer, it may be desirable to substantially
eliminate the flexibility of a net or fabric that has been placed
in end position. Such a pretreatment applies a thin coating to the
strands or fibers of the fabric. A net that is pretreated in end
position has many notable advantages. First, the frozen net keeps
material in discipline regardless of weather, such as wind, rain,
snow, and the like. Second, the frozen net retains a fixed shape
while a subsequent structural coating is applied. Third, the frozen
net provides an initial strength, which may be compressive,
tensile, or torsional. Fourth, the frozen net eliminates sagging or
stretching of material. Fifth, the frozen net increases the grip or
adhesion characteristic of the subsequently applied structural
coating that may constitute a compressive element, while the net is
a tensile element. Alternately, both net and applied coating may
add compressive and tensile values. Sixth, the frozen net saves
time and energy, contributing both a financial and environmental
benefit.
[0064] The ability to freeze or harden some known net materials by
pretreatment is specific to the chemistry of the material being
utilized for the net. For some known net materials, the application
of a hardener is well known. However, known processes for hardening
net material require that any plastic, polymer, or synthetic
coating on the net be thin enough to allow the hardener to
penetrate into the coating. To overcome this limitation, this
invention employs a pretreatment hardener that includes a solvent
base or other chemical for temporarily softening the coating, which
then allows the pretreatment hardener to penetrate the net
material. The softening process is short. The thinness of the
pretreatment coating allows the solvent or softener to evaporate
quickly or to otherwise become ineffective after accomplishing the
hardening and stiffening process. An alternative pretreatment may
be performed in two steps, first by applying the solvent or
softener, and second by following with a hardener that can
penetrate or be absorbed by the softened fabric fibers.
[0065] Another approach to pretreatment is to harden, stiffen, or
immobilize the fabric strands by coating them with an overcoat
that, on a micro-scale, forms an exoskeleton by encasing the
individual net strands. A suitable overcoating material must have
high modulus and high tensile strength characteristics. Optionally,
such material may have a fast or near instant set time in order to
eliminate delay due to curing times or delay due to windy
conditions. The overcoating material should be non-brittle when
set. Examples of overcoatings that fulfill these requirements are
urethanes such as polyurethanes, polyureas, acrylics, epoxies, and
such polymer-based materials as will provide a level of efficacy
for these characterized functions. In addition, cementitious base
materials are desirable and may include materials that set by
either hydration or polycondensation.
[0066] Pretreating by an overcoating material may be preferred over
a hardening material due to several efficiencies. First,
overcoating materials can be much less costly than various
proprietary chemicals for hardening plastic nets. Second, applying
an overcoating material can take less time, especially where a
solvent must be applied prior to applying a hardening agent. Third,
an overcoating agent typically can be applied in a single step,
where hardening agents may require two or more application steps.
Fourth, since an overcoat is on the outside of the existing net
material surface, the overcoating material utilizes a greater depth
of beam on micro scale and produces better strength efficiency.
Fifth, the use of overcoating material may allow greater economy in
selection of the net material. The overcoat or exoskeleton is
analogous to the upper and lower chord of an engineered floor joist
or roof rafter. In this arrangement, the net becomes structurally
more efficient. A net of lower structural capacity may be used
because of the compensating placement of the overcoat at a greater
distance from the center of the net fiber. Further the tensile load
bearing characteristics of the fiber strands may be efficiently
increased again providing cost economies from utilization of less
costly net materials.
[0067] With or without pretreatment, the fabric 32 is treated with
the principal coating layer 34 to form a structural shell. After
principal treatment, the treated net holds a fixed shape without
continued need for the framework 30, as shown in FIG. 2. The net is
treated by applying a layer 34 of surface treating agent such as
cementitious material. A suitable method of application is, for
example, by spraying onto the net. A material that hardens, cures,
or sets can be a suitable agent to treat the net and define layer
34. Unlike the pretreatment coating that might be of minor
thickness, the principal coating is of substantial thickness and
continuity. The net layer 32 and the coating layer 34 may become
integrated. A single numeral 35 will refer to a combined or
integrated unit that includes both a fabric portion and a principal
coating portion.
[0068] In the arrangement of layers as shown in FIGS. 10 and 11,
the applied principal coating material can form a structural layer
34 that is initially applied in juxtaposition to net 32. Because
the layer 34 will require support until it sets or otherwise
becomes self supporting, the net 32 can be stretched taut and
attached to framework 30 as needed, as best shown in FIG. 1. Known
fastening systems such as staples, nails, ties, and adhesives are
suitable to secure the net 32 with stretched tautness on frame 30.
Optionally, the net 32 is applied to the frame using gravity as the
primary means to plumb the fabric walls. [Para 63] The composition
of framework 30 is variable according to cost and availability of
supplies. Conventional wood framing members can be used, although
the framework does not require the close spacing of a conventional
stud wall. By way of example and not limitation, other candidate
materials include metal pipe, plastic pipe, expanded polystyrene
(EPS), bamboo sticks, steel rods and beams, aluminum rods and
beams, and inflatable tubing, including tubing constructed from
fire hose and then pressurized. The framework 30 might be removed
or removable. Alternatively, it may be preferred for the framework
30 to be retained in place as a permanent component of the building
structure, even if the resulting structural benefit of the
framework is small.
[0069] In optional variations of structure such as shown in FIGS.
11 and 17, the framework 30 is utilized to support multiple layers
of fabric and principal hardening agent. A first layer of the net
32 is followed by a layer 34 of principal treating agent, which
upon curing forms a self-supporting structure that is capable of
receiving and supporting further structural layers. Thus, the cured
first layer 35 receives and supports a second layer 36 of the net,
which may be either of the same or different composition from layer
32. The second layer 36 receives a second layer of a principal
coating 38, which may be of the same composition or different
composition from layer 34. For example, the second layer may form
an exterior skin over the building and may have a mix design suited
to reflect heat. Each layer 35 of a combined fabric and hardening
agent becomes structural upon curing. Accordingly, multiple layers
35 can be added in series, as desired.
[0070] After the principal coating layer 34 has been applied to the
net 32 and the net has been hardened, framework 30 may be removed,
as suggested in the view of FIG. 2. The resulting first structural
skin or shell 40 may be a building constituting a first end
product. In order to form a desired exoskeleton building structure,
the first shell 40 should be coated with an intermediate layer 70,
and a second shell should then be added to cover the intermediate
layer on the side opposite from the first shell 40. The building
shell 40 serves as a mold for application of one or more additional
layers of net 32, cementitious principal coating 34, and the like,
to define a finished exoskeleton structure. Supplemental principal
coating layer 38 of FIG. 10 is an example of a second skin of an
exoskeleton building.
[0071] The intermediate layer 70 may be formulated to constitute an
internal structural member, spacer, or insulation. As noted above,
a spacer is an important element of an exoskeleton structure. There
are well known formulas for computing moment of inertia of any beam
or assembly. Increases in the moment of inertia are proportional to
increases in the depth of member. Thus, the stated moment is
increased as the distance between the center of the walls, roof,
and floor, to the exterior structural member or skin is
increased.
[0072] The method of this invention enables the on-site
modification of building design, including both architectural
design and load capacity. The thickness of layer 70 establishes the
depth of beam of the exoskeleton, which is a critical factor in
adapting the building structure to various loading situations.
Varying the thickness of layer 70 is possible during on-site
construction to accommodate changes or newly obtained requirements
for the building structure. Similarly, by adding an additional
layer of net and fixing material to either or both of the skins of
the exoskeleton, it is possible to increase the tensile and
compressive capability of the skins while at the building site.
[0073] Another optional embodiment employs structural supporting
members 42 such as posts or other columns, illustrated in FIG. 2 as
being positioned against the outside surface of shell 40. In a
further illustrated variation, structural posts or columns 44 are
arranged in alternating and offset positions on both the inside
surface and outside of shell 40. The structural elements 42, 44 may
be arranged in an alternating pattern. As described in greater
detail below, a second skin of an exoskeleton structure may
overcoat the elements 42, 44 to incorporate them into the
exoskeleton as a unitary or monolithic unit.
[0074] A hardened net 32 may define a roof 46. Before hardening,
the net is applied to roof fabric supports 48, FIG. 1. If the
fabric is applied in tension, the net will define the shape of a
flat roof or flat roof panel. A roof panel 46 provides a useful
example of how easy and cost effective it is to increase the
strength of exoskeleton, even on-site during construction. In a
situation where the roof panel 46 must bear only limited load, a
flat panel 46 as shown in FIG. 2 may have sufficient structural
capability that it needs no additional coating other than the
fixing agent 34, forming a single flat shell wall 35. In a
situation where the roof 46 has more load, the exoskeleton formed
of shell layer 35 plus intermediate layer 70 plus opposite shell
layer 78 provides greater load bearing capability. In the more
extreme situation where roof panel 46 needs even more strength or
where span is great, the exoskeleton roof panel composed of layers
35, 70, and 78 can be reconfigured into a folded plate design such
as shown in FIG. 9, or into another panel shape that adds even more
depth of beam plus rebar for increased tensile requirement. This
sequence of increasing the capability of a roof is representative
of increased capability that can be applied to any portion of a
building structure. The load bearing capability of a structure can
be increased without requiring the typical delay and added cost of
ordering and obtaining larger or additional joists, trusses, or the
like according to conventional practices.
[0075] A folded plate is a series of triangular peaks and valleys
as viewed in profile, visible in FIGS. 3, 8, and 9. According to
the method of construction shown in FIG. 8, net 32 is applied to
parallel elongated transverse roof supports 50 arranged in
alternating high and low positions. Steel rod such as rebar is a
suitable choice for use as supports 50. Another suitable choice is
a flexible elongated member such as a cable, rope, or the like,
having suitable tensile capacity if required for loading or
span.
[0076] One method of applying net 32 to supports 50 is by weaving
the net over the high supports and under the low supports. Another
method is to lay the net over a series of high supports, allowing
slack net between the high supports. The low supports can be
dropped onto the slack areas to form troughs under force of
gravity. Various known fasteners and attachments such as hog rings
may be used as required to attach net to supports, such as at high
supports, at every support 50, or at the ends of the net 32, at the
final or end supports 50. According to FIG. 8, the fabric layer 32
is configured to a structural shape by the supports 50, which can
serve as either an additional structural element or the only
structural element.
[0077] The net 32 on roof 46 is hardened by application of a
coating layer 34, such as a cementitious or polymeric coating layer
34 to form the base layer of finished roof 46, FIG. 9. The layer of
treating composition 34 applied to the fabric 32 hardens to set the
fabric in a permanent shape. In order to form an exoskeleton
structure, an intermediate spacer layer 70 is placed over the base
layer of net and hardener; and a second layer of net and hardener
is placed over the intermediate layer 70. The layer of treating
composition 34 can be built up or thickened over the rebar 50 to
further enhance the integral strength of the structural elements in
assembly with the fabric 32. The lower supports 50 can be fully
encased by the hardener 34.
[0078] The resulting triangular profile of the roof section 46 has
inherent structural capacity even with rebar support removed. FIG.
3 shows the resulting roof 46, with a connected series of flat roof
segments at acute angles to one another defining troughs 52 and
peaks 54. Thus, the rebar supports can serve as another variety of
a temporary framework that holds a fabric or net in discipline or
desired shape. Application of a single layer of net 32 and a layer
of cementitious material 34 can complete the roof structure.
Alternatively, the roof 46 of FIGS. 3 and 9 may serve as a mold
that allows application of one or more additional layers of net 32
and treating material 34, described above.
[0079] Another embodiment of the roof 46 omits the low position
supports 50 of FIGS. 8 and 9, other than at the ends of the roof
where ends of the fabric might be secured to low position supports.
FIG. 4 shows a resulting roof section after it has been hardened or
frozen to shape. With the low position supports 50 absent, the
intermediate troughs of the roof 46 are curved between pairs of
upper supports 50 at a selected height. The resulting curves 56 may
be referred to as catenaries. The curved troughs have inherent
structural capacity. Catenaries are considered to be among the
strongest shapes to be placed under tensile stress across a span
between ribs.
[0080] For calculation purposes, the depth of the catenaries
corresponds to the depth of a structural member or beam. For
example, the beam depth in FIG. 4 can be measured as the vertical
distance between the top of a peak 54 to the low point of the
catenary 56. Any number of domes or other suitable repeating shapes
can be utilized to provide structural capacity, with or without
additional structural elements. In each case including the folded
plate, trough depth of the hardened fabric corresponds to beam
depth. Either temporary or permanent framework or exoskeleton will
establish the trough shape.
[0081] Where said roof section meets a wall, an alternate approach
is to have the wall define the depth of the section at the
juncture. The depth may be minimal, causing the catenary to have a
compound catenary shape. The shape may be a finished roof section,
or the shape may now be utilized as a mold for additional layers of
materials as suggested in FIGS. 10 and 11.
[0082] A roof of the type described is suited for use on both
rectangular structures and non-rectangular structures. For example,
the roof is adaptable for use on round, elliptical, or various
polygonal structures. Parallel arrangement of supports 50 may be
preferred for use on rectangular roof areas or to produce
individual rectangular roof segments. Converging radial or modified
radial arrangement or segments may be preferred on rounded and
irregular roof areas. In an appropriate situation, the roof may be
formed of a body of hardened net 35 having no supports 50 other
than at ends, as better shown and described in connection with FIG.
18.
[0083] FIG. 5 shows a segment or modified vault section 58 of a
rounded roof. The modified vault section includes both a wider end
60 and a narrower end 62, wherein the wider end typically is nearer
the periphery of the roof and the narrower end typically is nearer
the center. The roof segment 58 is configured as a modified vault
with inherent compressive load bearing capability. A method of
forming the roof section 58 is by draping a fabric sheet between
supports 50, FIGS. 8 and 9, such as of rebar. The fabric sheet
assumes a catenary shape. Treating the surface of the fabric with a
spray of hardening substance produces a hardened body 35 of the
structural roof element.
[0084] The roof segment 58 can be repeated as necessary to define
an entire circular, elliptical, or other rounded roof by arranging
the supporting elements 50 in a radiating or radial pattern, as
shown and suggested by FIG. 18. For example, a ring-like center
compression element 64 may support one end of radiating rebar
supports 50, and a ringlike peripheral or exterior tension element
66 may support the other end of the rebar members 50. The exterior
element 66 may be of another shape as required, such as an ellipse,
arc, polygon, or polygonal section.
[0085] The availability of a choice between parallel or radiating
supports 50 or the substantial non-use of supports demonstrates
that the roof system is adaptable to substantially any shape of
building. The invention contemplates the use of all permutations
and combinations of parallel, nonparallel, radiating, and other
arrangements of supports. The fabric or net 32 draped over the
supports 50 may be treated to form a finished section 35; or the
initial section 35 may serve as a mold for additional layers 35,
70, and 78.
[0086] Roof segments 58 can be used either as downwardly dished or
troughed segments such as shown in FIG. 5 or upwardly convex or
domed segments as shown in FIG. 6. A domed segment can be
fabricated by forming a dished segment and inverting it.
Alternately, the domed segment is fabricated by draping fabric over
a positive mold, such as one formed of expanded polystyrene, to
hold fabric layer 32 in shape until frozen by a layer of treating
agent 34. The mold may be retained under the roof segment or
removed. Optionally, the mold may have structural or insulative
characteristics.
[0087] Another configuration for a roof segment is the vault 68
shown in FIG. 7. These segments 68 can be fabricated by draping
fabric 32 over a framework as described in connection with FIG. 4.
The fabric assumes a natural curve. Cementitious material 34 is
applied to the fabric 32 and allowed to harden to form the curved
shape of the segment 68. The curved segment 68 is inverted for use
as the upwardly domed vault of FIG. 7. The vault shape also can be
fabricated in multiples, as suggested by the multiple troughs 56 of
FIG. 4. The multiple curved troughs 56 are turned upside down to
produce a multiple vault. A single wall 35 may form a finished
vault 68. One or more additional layers 35, 70, and 78 can be
added, either while the vault is in the troughed position of FIG. 4
or after inverted to the dome or vault position of FIG. 7.
[0088] As evident from the disclosures of FIGS. 3-7, a roof 46 can
be fabricated by forming structural members 35 of net 32 draped or
woven on elongated supports 50 and treated with a layer 34. The net
32 may be snug or loose between supports. The area of roof between
a pair of supports may be termed a segment, which optionally
includes the pair of elongated side supports 50. If loose, the net
32 may form smoothly curved troughs. Segments may be formed
individually or in groups. The supports 50 may be parallel or
on-parallel, and non-parallel versions may include radial or
radiating arrangements. The resulting segments will have parallel
sides or non-parallel sides, according to the arrangement of the
supports 50. Multiple joined segments or groups of segments may be
combined to define a roof 46.
[0089] The multiple segments might be formed as a compound unit as
suggested by FIGS. 8 and 9 or as individual segments that are
combined in juxtaposed relationship to form a roof 46. In either
form, the segments can be used in original, gravity-dictated
disposition or in inverted disposition; the latter being of
particular interest where an upwardly domed vault 68 or modified
vault 58 is the desired structure. Segments of any or all shapes
can be individually combined to form complex roof patterns. Any
segment design is capable of use in original disposition or
inverted disposition. Any segment is capable of use with its ends
reversed, such that, for example, the tapered segments 58 can be
alternated in series by reversing ends 60, 62 in any desired
frequency or pattern. Especially where individual segments are
assembled to form a roof, it is desirable to apply a unifying layer
of fabric 32 and a layer of hardening coating 34 of the
assemblage.
[0090] Variations in the layer structures are possible and
expected. The composition of the flexible net 32 may be of woven or
sheet material. Candidates include stucco netting, landscape cloth,
steel chicken wire, hardware cloth, basalt net, or aluminum screen.
The composition of the cloth or netting may be natural or
synthetic, including plastics and composites. Examples of suitable
materials include nylon, high-density polyethylene (HDPE),
low-density polyethylene (LDPE), polypropylene, and woven plant
products such as grasses, reeds, and leaves. The net 32 can be a
structural component of the finished building, or, optionally, in
some situations it may be removable. In the latter situation, the
net may be utilized only for purpose of being a temporary method
that holds or defines a shape for the cementitious material of
layer 34. After layer 34 hardens, the net might be removed, leaving
the layer 34 to serve as a residual structural element and as a
mold for receiving and shaping subsequent layers.
[0091] As shown in FIG. 10, a polymeric, cementitious, or other
hard setting principal layer 34 is applied over the net 32.
Cementitious materials include Portland cement and materials
sharing similar chemistry of hydration. Other cementitious
materials include geopolymers that are formed by the chemistry of
polycondensation. Typically the principal hardening layer 34 will
penetrate and bond with the net layer 32 such that the net is not
removable. Suitable materials for use in the principal hardening
layer 34 will cure or set by passage of time or other methods. Both
slow setting and fast setting materials are known. Accelerators may
be used as desired. A suitable set time might range from several
seconds to several hours.
[0092] A shell 40 or other component of a building formed according
to the invention may constitute an exoskeleton assembly. The
hardened layer 34 defines a first external structural skin of the
exoskeleton assembly. Preferably, a second external structural skin
is added, consisting of at least the second hardened layer 38. In
the case of compressive shapes such as vaults or domes, the inner
layer 34 need add little or no structural capacity--it simply may
act as a mold.
[0093] Principal hardened layer 34 may contain fibers that impart
structural characteristics to the layer. Other optional ingredients
include silica fume, plasticizers, or micro fibers added to the
cementitious mix design. Suitable components for inclusion in the
mix design are ceramic spheres, which may be synthetic or natural
as present in some ashes; polymers; corn or corn derivatives, which
may be by-products of processing; magnesium, such as magnesium
oxides; phosphates; micro fibers, which may include round or ring
shaped fibers; recyclable wastes; and other processed waste
materials including phosphogypsum and mine or mill tailings. Other
suitable additions include air or other materials among which may
be: cements; synthetic or natural ceramic spheres; expanded
polystyrene (EPS); soils; polymers; plasticizers; gelling
additives; ashes such as of coal ash, rice hull ash, corn ash,
bagasse ash, volcanic ash, or others; pumice; magnesium oxides;
phosphates; fine powders such as calcium carbonate, waste gypsum or
phosphogypsum, mine or mill tailings; and processed recyclable
wastes.
[0094] In addition to layers of netting and principal hardening
materials applied to the netting, an exoskeleton building
construction should include one or more additional intermediate
layers 70, shown in FIGS. 10 and 11, which may be a filler layer, a
strengthening layer, or an insulating layer. A base layer, skin, or
shell wall 35 acts as a backer board or mold to accept and provide
shape or control for the applied layer 70. Among suitable methods
for applying layer 70 are pneumatic application, spraying, and
pumping. Layer 70 may be stacked on or against a base layer 35,
using a minimal slump mix design. With a troughed roof 46, such as
shown in FIG. 9, layer 70 may fill the troughs to establish a
smooth or flat roof, which then can be coated with an external
finishing layer 35,78.
[0095] Where layer 70 is applied to add spacing or depth to a
building structure, layer 70 may be formed of honeycomb material
that provides depth of structural element or beam. Optionally layer
70 is composed of expanded cementitious materials, for example
expanded by air. The material forming the layer 70 may contain air
or other materials among which may be: cements; geopolymers;
synthetic or natural ceramic spheres; expanded polystyrene (EPS);
soils; polymers; plasticizers; gelling additives; ashes such as of
coal, rice hulls, corn, bagasse, volcanic, or others; pumice;
magnesium oxides; phosphates; fine powders such as calcium
carbonate, waste gypsum or phosphogypsum, mine or mill tailings;
and processed recyclable wastes. Such materials may be used as a
base raw material for a mix, or to expand a cementitious mix,
regardless of whether they provide significant structural strength.
The materials may have inherent compressive and tensile
characteristics by themselves. The composition of layer 70 may
offer insulating values to the building structure.
[0096] For economic and environmental advantage, layers 34, 38, and
70 may be fabricated from indigenous, low cost or freely obtainable
materials, especially recyclable materials. Certain suitable
materials may be an environmental liability to others. After such
materials are detoxified, they form suitable components for use in
the invention and need not be buried or otherwise stored. Some of
the materials otherwise must be sent to landfill or disposed of in
a manner that incurs costs. The ability to make beneficial use of
such materials creates a profit center. The materials chosen are
selected for utility in the invention and not on the basis of
whether they are recognized by building codes or engineering
standards. Likewise, it is optional whether such materials
contribute significant compressive or tensile strengths.
[0097] In FIGS. 10 and 11 a hardened second layer 38 covers layer
70. This layer is an outer structural shell or skin of an
exoskeleton assembly. Layer 70 provides depth of beam or strength
by increasing the space or moment of inertia for exterior
exoskeleton skins in the wall, floor, or roof. Layer 70 may be
formulated to provide insulation. Where several layers of the
assembly are built up, layer 38 may be the exterior skin or finish
coat of the built up assembly. Components of layer 38 may include
ceramic sphere admixtures that impart qualities of an effective
sound barrier and a high level of emissivity or reflectivity to the
material. Corn-derived admixtures are desirable to impart a high
level of emissivity, reflectivity, or thermally non-conductive
characteristics to the material. Fibers can impart structural
characteristics to the layer 38, adapting it as the final layer of
an on-site, built up, and structural exoskeleton assembly.
[0098] As shown in FIG. 11, an additional layer of net or fabric 36
can be utilized in the outer layer or skin of the exoskeleton
assembly. The layer 38 can be a hardening layer applied to the
fabric 36 to form a combined layer 78. The qualities of the
external layer can be chosen according to environmental
constraints. For example, materials such as ceramic spheres, corn
products, and gold are known to impart high reflectivity, which is
beneficial to stop heat transfer. The inner layer 34 also can be
adapted to local need according to the choice of added
components.
[0099] FIGS. 12-17 show examples of sections of a shell 40 using
the described variations of the invention. FIG. 12 shows a shell
section 40 made in accordance with FIG. 11. On one side, a surface
layer 35 is formed as illustrated in FIG. 11 of net 32 and hardened
material 34 and covers a core layer 70. An opposite surface layer
78 is formed of as illustrated in FIG. 11 of net 36 and hardened
layer 38.
[0100] FIG. 13 shows a shell section 40 made in accordance with a
modification of FIG. 10. A structural element 72, such as a post,
is monolithically incorporated into the material of an outer layer
38. A method of placing this layer is by casting, spraying, or
otherwise applying the coating in situ. The structural element 72
may be built around another element such as a length of steel rod
or rebar 74 within element 72. Examples of other possible included
elements 74 are prefabricated reinforcements and members formed, in
whole or in part, of wood, steel, basalt, aluminum, or bamboo. The
use of built up layers enables the element 72 to be an integral
structural component of the shell. Elements 72 can be posts 30 of
the initial support structure, FIG. 1. These posts 30 include outer
posts 42 and inner posts 44, FIG. 2, which may be opposite from one
another or spaced alternately on one or both sides of a wall.
[0101] FIG. 14 shows a shell section 40 built in accordance with a
modification of FIG. 11. An inner shell surface 35 covers one face
of the wall, and an outer shell surface 78, including both fabric
36 and principal coating 38, covers the opposite face. The
composition of shell surfaces 35 and 78 may be identical.
Structural elements 72 are fabricated as a monolithic part of both
shell surfaces. Net 32, 36 is a component of the respective shell
surfaces and is embedded in or overcoats the elements 72. The
principal coating layers 34 and 38 also overcoat the elements 72.
The elements 72 are arranged in offset alternating pattern taught
in U.S. Pat. No. 5,566,521.
[0102] FIG. 15 shows a shell section 40 in which the outer shell
coating 78 includes both an integrated net 36 and principal coating
38 applied as an overcoat over integrated structural elements 72.
The elements 72 are arranged in a juxtaposed configuration,
directly across from one another on opposite sides of the section.
At least some of the elements 72 include steel rod or rebar 74
bearing a point load. For example, the rebar 74 may be included in
elements 72 at the end of the section or under the end of a window
or door header.
[0103] FIG. 16 shows a shell section 40 formed of the single
integrated layer 35, which utilizes only net 32 and first hardener
34 as shown in FIG. 10. Optional structural elements 72 are
arranged on at least one side of the section. The net component of
unit 35 is incorporated into the elements 72. For example, the net
component may deviate from planar arrangement to overcoat the
elements 72. As another example, the net component may wrap or
encircle elements 72, such that the net component is located on
both inside and outside edges of the elements 72. The hardener
element of unit 35 is applied to the net to form an integral
section 40 formed of both shell and optional structural elements.
Any previously described placement or arrangement of structural
elements 72 can be utilized.
[0104] FIG. 17 shows a shell section 40 that functions as a mold.
One major side of this section 40 is formed of a shell wall 35,
which forms a first side of a two-sided exoskeleton. The opposite
major side is formed of shell wall 78. The two major sides are
spaced apart but closed at opposite ends, defining an intermediate
core area. The resulting structure of the shell section is a
suitable vessel or traditional mold assembly for receiving a
quantity of material suitable for forming intermediate layer 70
into the intermediate core area. Material for layer 70 can be
placed in the core area as a flowable liquid that will set or
solidify. Structural elements 72 are incorporated into one of the
shell sides 35. The net in this shell side 35 may wrap, overcoat,
or be incorporated into the element 72. The element 72 can be built
up monolithically with the net.
[0105] The novel method of forming the building section of FIG. 17
is, first, to establish the shape of the net for forming a first or
inside layer of the shell 40. Second, the net is hardened or fixed
by application of a fixing to the net, thereby forming finished
shell wall 35. The net and coating becomes a unified inside layer
35. The layer 35 is a tensile and compressive structural surface of
the exoskeleton. Layer 35 can be a finished coating or a final
product. Next, the spacer layer 70 is applied to one surface of
layer 35. Where the building structure is a wall, spacer 70 may be
laid up alongside layer 35. Where the building structure is a roof
or floor, spacer 70 may be laid on top of layer 35. Finally, an
opposite or outside surface 78, formed of net and fixing agent, is
applied over the intermediate spacer 70. Like wall 35, wall 78 is a
tensile and compressive structural surface. Wall 78 can be the
finished coating on the outside of wall 40.
[0106] The elements of a framework 30 may be supplemented by
elements 72 as shown in FIG. 17. Either framework 30 or other
elements 72 may be located between the shell sides 35, 78.
Framework elements 30 would be permanent and non-removable from the
section. In a method of forming the structure of FIG. 17, the
framework elements 30 are erected to support a subsequently formed
first shell side 35. The second shell side 78 is applied to the
respective opposite face of the elements 30, providing the
opposing, spaced shell of an exoskeleton and thereby defining the
vessel for receiving material 70. The thickness of the layer 70
spaces the two walls of the exoskeleton. The thickness of layer 70
further defines strength and insulation of a wall, roof, or floor
assembly.
[0107] Alternatively, posts or materials other than framework 30
can be utilized to position the second net or shell side 78. The
frame elements 30 or alternative posts are attached to the first
hardened shell side 35 to provide attachment and spacing for the
opposite shell side 78 of the mold assembly. A net is attached to
the second side of the posts or frame members 30 and hardened by
application of a principal hardening layer as previously described.
The resulting mold is filled with material 70, which is held in the
mold until material 70 hardens, such as by hydration or
polycondensation.
[0108] In embodiments discussed above, an intermediate layer of
expanded material may be applied to the first fixed net layer to
provide depth of member before the second net layer was applied and
fixed to increase the load bearing capacity of the assembly.
Alternately, a different shaped net, such as a folded plate
configuration may be applied to the first fixed net layer to
provide the intermediate space for increased depth of member.
Alternately, the folded plate may be the first net to be fixed. In
this embodiment, the first fixed net doubles as a first stand alone
and self supporting exo-skeleton shape and secondly as the first
layer of the assembly with at least one fixed net skin being
applied. In these cases, the efficiencies of the intermediate
spacer layer are at least partially determined by the minimization
of material utilized. In other words, the efficiency of the
intermediate spacer layer may be characterized in part by the
percentage of that intermediate space being occupied by air. A
greater percentage of air equates to greater efficiencies.
[0109] Thus, more efficient utilization of a non-linear reinforcing
bar to provide the requisite spacer layer may result in less
material and less labor being required. In an embodiment, the
non-linear reinforcing bar may be made of basalt. However, any
material that has sufficient load bearing capacities can be used.
In an embodiment, the first fixed net layer may include a first
flexible fabric having a tensile load bearing capacity of
20.times.10.sup.3-100.times.10.sup.3 psi (138-690 MPa) and a second
fixed net layer that includes a second flexible fabric having a
tensile load bearing capacity of
20.times.10.sup.3-100.times.10.sup.3 psi (138-690 MPa). In another
embodiment, the first fixed net layer includes a first fixing
material having a compressive load bearing capacity of
1.times.10.sup.3-20.times.10.sup.3 psi (7-140 MPa) and the second
fixed net layer includes a second fixing material having a
compressive load bearing capacity of
1.times.10.sup.3-20.times.10.sup.3 psi (7-140 MPa).
[0110] In the following embodiments, the first net or covering
layer may be attached to the non-linear reinforcing bar. In this
configuration, the non-linear reinforcing bar acts as a permanent
framework. When this alternate sequence of combining the coverings
with the non-linear reinforcing bar are used in a horizontal
orientation, the addition of a bottom, and in some cases a top,
linear reinforcing bar to the non-linear reinforcing bar may be
appropriate as shown in FIG. 20 and as discussed in more detail
below. When the load bearing capacity of the reinforcing bars act
as the support to fabricate the structure or component, external
supports can be eliminated. In an embodiment, the non-linear
reinforcing structure includes an intermediate fixed net and may,
for example, be configured as a folded plate structure. The
intermediate fixed net may be made of any suitable fiber material
such as basalt.
[0111] This embodiment has the structural advantage of having the
ability to provide a shape that can more efficiently accommodate
loads inherent to long spans. The previous methods of stacking up
layers cannot provide this advantage. Further, as is well known to
those engineers in the pre-cast concrete industry, such
structurally efficient shapes have historically been made by
casting the requisite tensile load bearing materials in combination
with the compressive load bearing cementitious materials inside of
a mold. As is known to such professionals, the mold is the required
feature or assembly that defines the structurally advantageous
shape for the requisite tensile and compressive materials.
[0112] The present embodiment has the advantage of minimizing the
intermediate materials disclosed in U.S. Pat. No. 8,104,233. The
present embodiments provide improvements in the methodology of
fabricating multiple efficient load bearing shapes in monolithic
assemblies by including the new reinforcing bar spacer with
appropriately chosen external coverings or skins layers. The
non-linear intermediate reinforcing bar spacer layer, structurally
advantageously shaped, in combination with appropriately specified
coverings or external layers may enable the engineer to design and
fabricate, in-situ, structurally reinforced load bearing assemblies
appropriate for long spans and large loads that here-to-for could
only be fabricated in pre-cast concrete plants and steel
fabrication plants. The traditional pre-cast components would then
need to be transported to the final destination where they would
typically be placed in final position of use by a crane or other
heavy industrial equipment suitable for handling such loads.
[0113] The present methods overcome the challenges of load bearing
applications by providing the tensile and compressive load bearing
elements, in combination with appropriate depth of member, in a
successive and cumulative fabrication method that achieves the
required load bearing capacity as it is being fabricated in-situ or
elsewhere. In other words, the constituent non-linear reinforcing
bar and exterior shell or skin components may be fabricated
in-place pursuant to known structural design parameters to maximize
the efficiency of the structure, while minimizing the required
construction infrastructure, such as the heavy equipment, trucks,
cranes, steel plants, pre-cast concrete plants, transports etc.
[0114] In an aspect, the non-linear reinforcing bar spacer may
define large empty spaces that may be filled only with air. For
example, the non-linear structure may fill less than 10% of gap,
such as less than 5% or less than 1%. In an embodiment, a non-load
bearing filler, such as an insulation material, may also be added
in the space between outer and inner fixed net layers.
[0115] The efficient use of intermediate shapes has been practiced
in pre-cast concrete plants, structural steel fabrication plants,
and even in structural wood fabrication plants. However, in all
these applications, the plant was located remote from the job site.
Thus, traditional methods of fabrication include the freight of the
finished structural components to the site as well as the cost of
the fabrication plant itself, which is typically multiple millions
of dollars.
[0116] Another aspect concerns the limitation of the traditional
methods in providing specified sizes and configurations of load
bearing elements in assembly due to size and weight restrictions
imposed by roadway authorities as well as the limitations of the
roads themselves to accommodate such loads.
[0117] Embodiments of the method of fabrication provide any shape,
any thickness, any height, any breadth, any length, any size that
might be required. For example, load bearing structures according
to embodiments may have a length of about 5-300 feet (1.5-91.5
meters) and a width of about 5-150 feet (1.5-46 meters), such as a
length of about 7-175 feet (2-53 meters) and a width of about 6-40
feet (1.8-12 meters). Such assemblies do not have to be lifted or
placed into their final position for use.
[0118] The load bearing structures disclosed herein may form
components of building, such as walls and roofs. Further, the load
bearing structures may be assembled to form a load bearing
exoskeleton. In the case of roof or floor assemblies, the
pre-existing walls may provide the support to properly situate the
roof or floor assembly in its final position of use within the
building or structure. This feature can effectively eliminate all
supports, formwork, framework and mold work. Thus, the load bearing
structure may be fabricated in-situ without molds, supports,
formwork or framework. Assemblies that can be made with embodiments
of the load bearing structures and methods include, but are not
limited to, residential structures, commercial structures, bridges
and dams. Alternatively, the load bearing structures may be a
portion of a ship or boat, such as the hull or part of the
superstructure.
[0119] An example of a reinforced load bearing structure 100
according to an embodiment is illustrated in FIG. 20. The example
is based on Ultimate Strength Design theory, which is recognized in
the field of structural engineering, and can be found in
textbooks/reference books on reinforced concrete design. Textbooks
and reference books include, but are not limited to, Building Code
Requirements for Structural Concrete (ACI 318-02) by the American
Concrete Institute; Structural Engineering Handbook, Section 11,
Reinforced-concrete Design by Raymond C. Reese--Published by
McGraw-Hill Book Company and Design of Concrete Structures by
George Winter, Chapter 3 Published by McGraw-Hill Book Company, the
contents of which are hereby incorporated by reference.
[0120] The load bearing structure 100 may include a top fixed layer
101 which includes a top layer reinforcing net 102 fixed in a top
layer of fixative 104. The load bearing structure 100 may also
include a bottom fixed layer 105 which includes a bottom layer
reinforcing net 106 fixed in a bottom layer of fixative 108.
Located between the bottom surface of the top layer 101 and the top
surface of the bottom fixed layer 105 may be a gap 112. The depth
of member D of the load bearing structure 100 may extend from the
top surface of the top layer of the top fixed layer 101 to the
bottom surface of the bottom fixed layer 105, and therefore may
include the thickness of the top fixed layer 101, the thickness of
the bottom fixed layer 105 and the gap 112.
[0121] The load bearing structure 100 may also include a non-linear
reinforcing structure 110 which zigzags between the top layer
reinforcing net 102 of the top fixed layer 101 and the bottom layer
reinforcing net 106 of the bottom fixed layer 105. The spacing
between the zigzags of the non-linear reinforcement structure is
indicated by the symbol `b` in FIG. 20. The non-linear reinforcing
structure 110 may be in communication with the first and second net
layers, and may be configured to share with the first and second
fixed net layers a load applied to the load bearing structure. That
is, when a load is applied to the top of the load bearing structure
100, this applied load is distributed among the top fixed layer
101, the non-linear reinforcing structure 110 and the bottom fixed
layer 105 via the non-linear reinforcing structure 110.
[0122] When a load is applied to the load bearing structure 100,
both tensile and compressive loading are generated. The load
bearing structure 100 may be designed so that the tensile load is
primarily borne by the reinforcing nets 102, 106 and the non-linear
reinforcing structure 110, while the compressive load is borne by
the top and bottom layer of fixatives 104, 108. The area of the top
layer of fixative 104 in compression may be determined by
multiplying the spacing `b` of the zigzag reinforcement times the
thickness Tt of the top layer of fixative 104. The total
compressive force C in this area is the allowable fixative material
stress, such as 1,000 to 15,000 psi, times the area.
[0123] The area of the bottom layer reinforcing net 106 of the
bottom fixed layer 105 may serve as a tensile resisting element
with an allowable yield stress, such as from 20,000 to 170,000
pounds per square-inch (psi). The total tensile force F is equal to
the allowable yield stress times the area of the tensile
reinforcement. The following example illustrates a determination of
the moment capacity of the load bearing structure 100 illustrated
in FIG. 20. In this example, the selected numeric values are
provided in parenthesis: [0124] 1. The spacing between the zig-zag
reinforcement=b (=24'') [0125] 2. The thickness of the top fixative
layer=T.sub.t (=2'') [0126] 3. The thickness of the bottom fixative
layer=T.sub.b (=2'') [0127] 4. The total depth of the section is D
(=10'') [0128] 5. The distance between the upper surface of the top
fixative material and the center of the bottom net reinforcing=c
(=9'') [0129] 6. The allowable compressive stress in the top
fixative layer=f.sub.c (=5,000 psi) [0130] 7. The yield stress of
the bottom layer of the net reinforcing=f.sub.y (=60,000 psi)
[0131] 8. The area of the bottom layer of net reinforcing=A.sub.r
(=1.00 in.sup.2) [0132] 9. The distance or moment arm for
determining the ultimate moment=d (=c-a/2), where a is the depth of
the stress block in the upper fixed layer
[0133] The depth "a" of the stress block in the upper fixed layer
101 may be determined from the area A.sub.r of the bottom layer of
net reinforcing, yield stress f.sub.y of the bottom layer of the
net reinforcing, spacing b between the zig-zag reinforcement and
the allowable compressive stress f.sub.c in the top fixative layer.
Equation 1 below illustrates the calculation:
a = A r f y 0 . 8 5 b f c Equation 1 ##EQU00001##
Given an area A.sub.r of the bottom layer of net reinforcing of 1
in.sup.2, a yield stress f.sub.y of the bottom layer of the net
reinforcing of 60,000 psi, a spacing b between the zig-zag
reinforcement of 24 inches and the allowable compressive stress
f.sub.c in the top fixed layer of 5000 psi, the depth "a" of the
stress block in the upper fixed layer 101 is
1.times.60,000/0.85.times.24.times.5,000=0.6''.
[0134] With the depth "a" of the stress block in the upper fixed
layer 101, the ultimate moment capacity M.sub.u of the section can
be determined with Equation 2 below:
m u = 0 . 9 A r f y ( d - a 2 ) Equation 2 ##EQU00002##
Given an area A.sub.r of the bottom layer of net reinforcing of 1
in.sup.2, a yield stress f.sub.y of the bottom layer of the net
reinforcing of 60,000 psi, a moment arm d of 9 in. and the depth a
of the stress block of 0.6 in as determined by Equation 1, the
ultimate moment capacity M.sub.u is 0.9.times.1.00.times.60,000
(9.00-0.60/2)=469,800 i-lb=19,575 f-lb/ft of width of section.
[0135] If the density of the fixative material is 144 pcf, then the
weight of the material is 48 psf Assuming the section spans a
distance of 16.0 ft, the allowable uniform load is then:
q=((8.times.19,575/16.times.16)-1.2.times.48)/1.6=376 psf.
[0136] FIG. 21 is a table comparing an embodiment with conventional
building materials. The examples have been normalized for a 24 foot
span. A span made of geopolymer with a basalt fiber net
reinforcement according to an embodiment has a weight of
approximately 6000 pounds and can support of weight of 68,400
pounds. This results in a live load ratio of 11.4. Further, at
today's material prices, the cost of the structure is one third the
cost of the next best alternative, concrete with steel reinforcing
bar. The conventional concrete with steel reinforcing bar is not
only more expensive, but heavier than and supports less weight than
a span made according to the teachings herein.
[0137] A span made of conventional timber beams would be lighter
than the comparative embodiment. However, a timber span would
support less total load. Additionally, a comparable span made of
timber would cost approximately four times as much per pound of
design load. A span made of glue laminated timber (glulam) is
slightly heavier than conventional timber but cannot support much
higher loads. However, glulam is much more expensive than timber.
Thus, the cost per live load is comparable while the cost per
linear foot is greater than conventional timber and much greater
than a span fabricated according the teachings herein.
[0138] A 24 foot span made with steel beams without the addition of
concrete, would weigh less than other conventional materials and
support the highest load. However, a span made entirely of steel
would be prohibitively expensive, almost eight times the cost of a
span made of geopolymer reinforced with basalt.
[0139] Although the foregoing refers to particular preferred
embodiments, it will be understood that the invention is not so
limited. It will occur to those of ordinary skill in the art that
various modifications may be made to the disclosed embodiments and
that such modifications are intended to be within the scope of the
invention. All of the publications, patent applications and patents
cited herein are incorporated herein by reference in their
entirety.
* * * * *