U.S. patent application number 10/639378 was filed with the patent office on 2004-06-03 for composite structural member.
Invention is credited to Salzsauler, Donald, Salzsauler, Roy.
Application Number | 20040103613 10/639378 |
Document ID | / |
Family ID | 31715873 |
Filed Date | 2004-06-03 |
United States Patent
Application |
20040103613 |
Kind Code |
A1 |
Salzsauler, Donald ; et
al. |
June 3, 2004 |
Composite structural member
Abstract
A composite structural panel is provided. The panel comprises a
frame having a longitudinal frame axis; a plurality of beam
elements mounted in the frame, each of the beam elements has a
respective longitudinal beam axis generally parallel to the frame
axis; a reinforcing fibre wrapping that extends around each of the
beam elements, the wrapping has a fibre direction running generally
obliquely to the beam axis; a plurality of wire strands that extend
about the wrapping, the wire strands run generally parallel to the
beam axis and the frame axis; an outer layer of reinforcing fibre
mat that surround the frame, the wrapped beams and the wire
strands, the mat has a majority of its fibres running generally
parallel to the frame axis; and, a solidified epoxy resin that
extends throughout and encasing the beam elements, beam wrapping,
wire strands, outer layer and frame.
Inventors: |
Salzsauler, Donald;
(Georgetown, CA) ; Salzsauler, Roy; (Christ
Church, BB) |
Correspondence
Address: |
John B. Hardaway, III
NEXSEN PRUET JACOBS & POLLARD, LLC
P.O. Box 10107
Greenville
SC
29603
US
|
Family ID: |
31715873 |
Appl. No.: |
10/639378 |
Filed: |
August 12, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60402550 |
Aug 12, 2002 |
|
|
|
Current U.S.
Class: |
52/676 ;
52/309.16; 52/309.7 |
Current CPC
Class: |
E01D 2101/40 20130101;
E01D 2101/10 20130101; E01D 19/125 20130101; E04C 2/386
20130101 |
Class at
Publication: |
052/676 ;
052/309.7; 052/309.16 |
International
Class: |
E04F 019/10; E04C
001/00 |
Claims
We claim:
1. A structural panel comprising: a frame having a longitudinal
frame axis; a plurality of beam elements mounted in said frame,
each of said beam elements having a respective longitudinal beam
axis generally parallel to said frame axis; a reinforcing fibre
wrapping extending around each of said beam elements, said wrapping
having a fibre direction running generally obliquely to said beam
axis; a plurality of wire strands extending about said wrapping,
said wire strands running generally parallel to said beam axis and
said frame axis; an outer layer of reinforcing fibre mat
surrounding said frame, said wrapped beams and said wire strands,
said mat having a majority of its fibres running generally parallel
to said frame axis; and, a solidified epoxy resin extending
throughout and encasing said beam elements, beam wrapping, wire
strands, outer layer and frame.
2. The structural panel of claim 1 wherein: said frame is
configured to receive at least opposite ends of said beams; and,
said reinforcing fibre mats of said beam wrapping and said outer
layer are of a glassy fibre.
3. The structural panel of claim 2 wherein: said reinforcing fibre
mat of said beam wrapping is a woven mat having about the same
quantity of fibres extending in each of two generally orthogonal
directions; and, said reinforcing fibre mat of said outer layer has
about 90% of its fibres extending longitudinally generally parallel
to said beam axis.
4. The structural panel of claim 3 wherein: said beams are of wood;
and, said wire strands are of steel.
5. The structural panel of claim 4 wherein: each of said beams is
made up of a plurality of panels having adjacent faces laminated
together and having a grain running along said beam axis; and, said
wires are of high tensile strength steel.
6. The structural panel of claim 5 wherein: said structural panel
is a bridge deck having an upper face coated with a road surfacing
material; and, said planks are aligned with said adjacent faces
generally parallel to said upper face.
7. The structural panel of claim 6 wherein: said upper face is
canted with a longitudinally extending centre section higher than
and sloping toward opposite side edges of said structural panel to
promote drainage.
8. The structural panel of claim 7 wherein: said structural panel
is thicker at said opposite side edges than at said centre section
thereby providing a curb at said outer edges with enhanced
stiffness to allow said structural panel to be thinner at said
centre section than would be required of a panel having the same
load bearing capacity but of generally constant thickness.
9. The structural panel of claim 8 wherein: said frame has
longitudinally extending edge flanges generally parallel to said
frame axis; said frame has a plurality of spars extending there
across between said edge flanges; said spars have sockets formed
therein toward said upper face for receiving said opposite ends of
said beam elements.
Description
FIELD OF THE INVENTION
[0001] The invention relates to a structural member, generally. In
particular, the invention relates to a structural member
constructed of composite materials.
BACKGROUND OF THE INVENTION
[0002] Structural members (e.g., columns or beams) may be
constructed of a variety of building materials, such as concrete,
wood or steel, each of which has particularly advantageous or
disadvantageous structural and load bearing properties. For
example, concrete alone has fairly good compressive strength
however its tensile and bending strength can be improved greatly
with the use of reinforcing materials such as hoop steel. Without
any reinforcement, however, transverse and axial loads may cause a
concrete support structure to spall and ultimately fail.
[0003] Wood is often used in structural applications because it too
has good load bearing properties. Wood may be described as an
orthotropic material. It has unique and independent mechanical
properties in the directions of three mutually perpendicular axes
(longitudinal, radial and tangential).
[0004] When a wooden beam is subjected to a load that is
perpendicular to the longitudinal direction of the wood body, the
wood fibers opposite the load are subjected to tension forces and
wood fibers adjacent the load are subjected to compression forces.
Under a heavy load, a wood beam may fail in either the compressive
or tensile half of the wood beam.
[0005] There are drawbacks to using non-reinforced wood as a
building material. For example, wood deteriorates under certain
conditions, such as a high moisture or wet environment. Wood is
primarily composed of cellulose, lignin, hemicelluloses and minor
amounts of extraneous materials. Cellulose is a
high-molecular-weight linear polymer consisting of chains of
glucose monomers. The cellulose molecules are arranged in ordered
strands, which in turn are organized into the larger structural
elements that make up the cell wall of wood fibers. Lignin is
concentrated toward the outside and between the cells. It is the
cementing agent that binds individual cells. It is a
three-dimensional phenyl-propanol polymer. The hemicelluloses are
associated with cellulose and are branched, low molecular weight
polymers composed of several different kinds of pentose and hexose
sugar monomers. As the cellulose, lignan, hemicelluloses structure
deteriorates, the wood fiber strength is compromised and as a
result, so are its load bearing capabilities. Under this weakened
condition, the wood is more prone to failure under load. Also,
despite any environmental deterioration, wood, under a high load
may still experience compression or tension failure if it is not
reinforced.
[0006] Previous attempts to reinforce concrete, wood or steel
support structures (e.g., Michalcewiz U.S. Pat. No. 5,505,030)
involve using pre-made reinforcing layers which are attached or
fitted to the element being reinforced, thereby increasing the
reinforced element's compressive, shear or load bearing capacity.
Solutions of this type, however, are merely prophylactic because
they do not address the underlying problem of using a building
material that is susceptible to load failure. The effective use of
casing reinforcing materials, such as described by Michalcewiz, is
further limited by the fact that they are merely surface
treatments. It may not be possible to apply reinforcing materials
to parts of a structure that are not readily accessible.
[0007] There remains a need for a composite structural member with
increased resistance to failure under load.
SUMMARY OF THE INVENTION
[0008] The present invention provides a structural panel comprising
a frame having a longitudinal frame axis; a plurality of beam
elements mounted in the frame, each of the beam elements has a
respective longitudinal beam axis generally parallel to the frame
axis; a reinforcing fibre wrapping that extends around each of the
beam elements, the wrapping has a fibre direction running generally
obliquely to the beam axis; a plurality of wire strands that extend
about the wrapping, the wire strands run generally parallel to the
beam axis and the frame axis; an outer layer of reinforcing fibre
mat that surround the frame, the wrapped beams and the wire
strands, the mat has a majority of its fibres running generally
parallel to the frame axis; and, a solidified epoxy resin that
extends throughout and encasing the beam elements, beam wrapping,
wire strands, outer layer and frame.
[0009] The reinforcing fibre mat of the beam wrapping may be a
woven mat having about the same quantity of fibres extending in
each of two generally orthogonal directions.
[0010] The beams may be made up of a plurality of panels having
adjacent faces laminated together and having a grain running along
the beam axis.
[0011] The structural panel may be a bridge deck having an upper
face coated with a road surfacing material.
[0012] The upper face may be canted with a longitudinally extending
centre section higher than and sloping toward opposite side edges
of the structural panel to promote drainage.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Preferred embodiments of the present invention are described
below with reference to the accompanying drawings in which:
[0014] FIG. 1 is a schematic view illustrating a composite
structural member according to the present invention;
[0015] FIG. 2 is a schematic view illustrating a beam according to
the present invention and the beam's grain orientation relative to
its longitudinal axis;
[0016] FIGS. 3a-b are schematic views illustrating alternate
orientations of a fibrous material in sheet form and its
orientation as it extends about and between a plurality of beams
according to the present invention;
[0017] FIGS. 4a-b are schematic views illustrating the use of a
fibrous material in cord form and its orientation as it extends
about and between a plurality of beams according to the present
invention;
[0018] FIGS. 5a-b are schematic views illustrating the use of a
fibrous material in both sheet and cord form in a structure
according to the present invention.
[0019] FIGS. 6 is a perspective cross-sectional view of a composite
structural member according to an embodiment of the present
invention;
[0020] FIG. 7 is a cross-sectional view of a bridge and its
associated components assembled using a composite structural member
according to an embodiment of the present invention;
[0021] FIG. 8(a) is a schematic plan view of a structural panel
according to an alternate embodiment of the present invention;
[0022] FIG. 8(b) is a schematic cross-sectional view of the
structural panel of FIG. 8(a);
[0023] FIG. 9 is a plan view of a frame element of the structural
panel of FIG. 8 (a) according to the present invention;
[0024] FIG. 10(a) is a longitudinal cross-sectional view of the
frame of FIG. 9 according to an embodiment of the present
invention;
[0025] FIG. 10(b) is a longitudinal cross-sectional view of the
frame of FIG. 9 according to an alternate embodiment of the present
invention;
[0026] FIG. 10(c) is a cross-sectional view of the frame of FIG. 9
according to an embodiment of the present invention;
[0027] FIG. 11 is a partial plan view of an end portion of a beam
element of the structural panel of FIG. 8 according to an
embodiment of the present invention;
[0028] FIG. 12 is a perspective view of an end portion of a beam
element of the structural panel of FIG. 8 according to an
embodiment of the present invention;
[0029] FIG. 13 is a perspective cross-sectional view of a bridge
deck according to an embodiment of the present invention;
[0030] FIG. 14 is a perspective view of a beam element of the
structural panel of FIG. 8 according to an embodiment of the
present invention;
[0031] FIG. 15 is an exploded view of the constituent components of
the structural panel of FIG. 8 according to an embodiment of the
present invention; and,
[0032] FIG. 16 is a perspective cross-sectional view of the
structural panel of FIG. 8 according to an embodiment of the
present invention.
DETAILED DESCRIPTION
[0033] FIG. 1 illustrates a composite structural member (CSM) 10
made in accordance with a preferred embodiment of the
invention.
[0034] Referring to FIGS. 1-2 and 6, the CSM 10 has a plurality of
beams 20, each beam having a longitudinal axis 22 and at least one
side 24 generally parallel to and facing at least part of a side 26
of at least one adjacent beam 20. A fibrous material 30 extends
about and between the beams 20. A potting material 40 permeates the
fibrous material 30 and encases the beams 20. The fibrous material
30 and potting material 40 are selected to yield a resistance to
bending in the CSM 10 that is greater than the combined individual
resistance to bending of the beams 20.
[0035] Each beam 20 has a grain direction 28 that is generally
aligned with the longitudinal axis 22. and is preferably a member
selected from the group consisting of wood and wood composites. In
an alternate embodiment, the beams 20 may be constructed of
concrete, fiberglass, and possibly other materials with properties
similar to a wooden beam.
[0036] In a preferred embodiment, the surfaces of the wooden beams
20 and the fibrous material 30 should be treated to clean and
prepare the surfaces for bonding. To enhance the bonding between
the wooden beams 20 and the fibrous material 30, the wooden beams
should be dry with their surfaces relatively free from grease,
excessive dust, etc. Preferably the surfaces should be rough to
enhance adhesion. A water proofing treatment might also be
considered, particularly where the CSM 10 is to be used in a
submersed or partially submersed environment and there is a risk of
the encapsulating material being damaged so as to expose the wooden
beams 20 to water.
[0037] Referring to FIGS. 3-5, the fibrous material 30 is
constructed of engineering materials having a high tensile
strength. In alternate embodiments, a fibrous material 30 having
higher or lower tensile strength and modulus properties may be used
depending on the particular application of the invention.
[0038] Referring to FIG. 5a, an embodiment of the fibrous material
30 is in sheet form 32. In an alternate embodiment depicted in FIG.
5b, the fibrous material is in cord form 36. The fibrous material
30 in the sheet form 32 may have variety of fiber architectures. In
a preferred embodiment, the fibers 34 are woven. Alternately, the
fibers 34 may be braided or knitted. The majority of the fibers 34
in the sheet form 32 are preferably unidirectional in the
longitudinal direction of the sheet form.
[0039] Referring now to FIG. 3a, the fibers 34 of the sheet form 32
are preferably aligned generally transversely (i.e. non-parallel)
relative to the longitudinal axis 22 of the beams 20. FIG. 3b
illustrates an alternate embodiment where the fibers 34 of the
sheet form 32 are aligned generally diagonally relative to the
longitudinal axis 22 of the beams 20.
[0040] FIG. 4a illustrates a further embodiment. The fibers 34 of
the cord form 36 run generally transversely relative to the
longitudinal axis 22 of the beams 20. FIG. 4b illustrates a still
further embodiment where the fibers 34 of the cord form 36 run
generally diagonally relative to the longitudinal axis 22 of the
beams 20. FIG. 6 depicts a still further embodiment wherein the
fibrous material 30 extends around an individual beam 20, but does
not extend around any adjacent beams 20.
[0041] In a preferred embodiment of the invention, the fibrous
material is a member selected from the group consisting of glass,
carbon, Kevlar.TM., aramids, nylon, possibly natural fibers (e.g.
hemp) and combinations of the foregoing.
[0042] Referring now to FIG. 1, the potting material 40 is a
curable resin such as vinyl esters, poly esters, urethanes, BMIs,
phenolics, acrylics, epoxies, cynate esters and thermoplastics. The
potting material is preferably an epoxy that has exceptional
adherence to steel, such as the Jeffco 4101-08 epoxy resin and
Jeffco 4101-18 epoxy hardener as manufactured by Jeffco Ltd. of San
Diego, Calif.
[0043] The term "resin" refers to any substance, or combination of
substances, of a suitable viscosity, such that they can be used to
impregnate the fibrous materials and surround the plurality of
beams and ultimately undergo a physical state transformation from a
low viscosity fluid to a rigid solid state wherein said
transformation can occur via various means such as chemical
reactions, a thermal cycle, etc. and acts as a binding matrix of
the fibrous material and beams to create a final composite
material.
[0044] A "Vacuum Assisted Resin Transfer Method" (VART) may be
utilized to encase the beam/fibrous material structure in resin.
This is a known method of impregnating fibers with resin.
[0045] Sample Applications
[0046] Bridge construction is a sample application of the CSM 10 of
the present invention that illustrates its unique and enhanced load
bearing properties over prior generation composite structural
materials.
[0047] Referring to FIG. 7, a bridge 70 consisting of a
substructure and a superstructure is illustrated. Substructure
elements include abutments 72, piers or pilings. Superstructure
elements, which sit atop the substructure, include stringers and or
a deck 74. These structural elements experience compression and
tension forces from several potential sources. For example, an
abutment 72, pier or piling, would experience compression forces 76
from the weight of the superstructure, the weight of any body
positioned on the superstructure and the weight of the abutment 72
pier or piling itself. Superstructure elements, such as the decking
74, may experience compression forces 77 and tension forces 78 from
the weight of the decking 74 itself as well as any body 79 sitting
on the decking. The combined compression and tension forces may
cause the bridge structural elements to buckle (in the areas
experiencing compression forces) and or snap (in areas experiencing
tension).
[0048] A composite structural member of the type described in the
present invention dissipates the compression and tension forces
over the whole of the structural member, unlike individual
structural members, such as wooden beams or glue-laminated timber
(glulam). This load dissipating property of the CSM 10 permits the
construction of bridges of greater scale and enhanced load-bearing
properties. This is because the load-bearing versus weight ratio of
the composite structural member of the present invention is several
times that of concrete or steel.
[0049] Bridge construction using the CSM 10 creates an integrated
structure where the decking is self-supporting, rather than simply
used as cladding. The structural strength of the CSM 10 stems from
the fact that the combined strength of the CSM 10 components
exceeds that of the beams and the potted encasement elements on
their own, in the configuration in which they are present.
[0050] Alternate Embodiment
[0051] Referring to FIGS. 8(a)-(b), 15 and 16, a composite
structural member according to a preferred embodiment of the
present invention is illustrated. The composite structural member
or structural panel 100 is comprised of a frame 101 having a
longitudinal frame axis 103. A plurality of beam elements 105 are
mounted in the frame 101, each of the beam elements 105 has a
respective longitudinal beam axis 107 that is generally parallel to
the frame axis 103. The beam elements 105 are wrapped in a beam
wrapping 109 of reinforcing fibre mat that extends around each of
the beam elements 105, the beam wrapping 109 has a fibre direction
running generally on a bias with (or obliquely to) the beam axis
107. The structural panel 100 further includes a plurality of wire
strands 111 that extend about the wrapping 109. The wire strands
111 run generally parallel to the beam axis 107 and the frame axis
103. There may also be transverse wire strands 151. The frame 101,
wrapping 109, beams 105 and wire strands 111 are further wrapped
and surrounded by an outer layer of reinforcing fibre mat 113 that
has a majority of its fibres 115 extending longitudinally generally
parallel to the frame axis 103. A solidified epoxy resin 117
extends throughout and encases the beam elements 105, beam wrapping
109, wire strands 111, outer layer 113 and frame 101.
[0052] Referring to FIG. 9, the frame 101 defines and determines
the approximate size and shape of the structural panel 100. In a
preferred embodiment, the frame 101 is comprised of two side
members 119 positioned opposite each other and running generally
parallel to the longitudinal frame axis 103. The side members 119
are connected to each other via two end members 121, which are
positioned opposite each other and generally orthogonal to the side
members 119. In an alternate embodiment, the frame 101 is a unitary
structure. Any other frame configuration known to those skilled in
the art that defines and determines the approximate size and shape
of the structural panel 100 may be employed.
[0053] The frame 101 may be comprised of steel. In a preferred
embodiment, the frame 101 is comprised of a mild steel, such as a
44W High Strength Low Alloy steel, although any standard grade
steel that can be flame cut, formed, drilled, welded and/or
machined by any normal means may be employed.
[0054] Referring to FIG. 10(a), cross-sectional view of the frame
101 along the frame axis 103 according to a preferred embodiment of
the present invention is illustrated. The frame 101 of structural
panel 100 is configured to receive at least opposite ends of the
beams 105. The end members 121 are recessed or cut out along their
respective lengths in order to provide a beam receiving surface 123
for receiving opposite ends of the beam 105. The recess 125 may be
of any shape known to those skilled in the art (e.g. flat, bevelled
or curved) that defines a beam receiving surface 123. An alternate
embodiment of the end members 121 is illustrated in FIG. 10(b). In
this embodiment, the end members 121 are not cut out, but rather,
the end members 121 have at least one hole or passage 127 passing
through the end members 121. A fastener 129 passes through the
respective end members and secures the beams 105 to the frame
101.
[0055] In a preferred embodiment, the frame 101 has longitudinally
extending edge flanges 131 that are generally parallel to the frame
axis 103.
[0056] Referring to FIG. 16, a perspective cross-sectional view of
the structural panel 100 is illustrated. The frame 101 preferably
has a plurality of spars 133 extending across the frame between the
edge flanges 131 and the spars 133 have sockets 135 formed therein
for receiving the opposite ends of the beam elements 105.
[0057] Referring to FIG. 11, an end section 137 of the beam 105
according to a preferred embodiment of the present invention is
illustrated. The beam 105 is wrapped in a beam wrapping 109
comprised of reinforcing glassy fibres 139. In a preferred
embodiment the glassy fibre is standard fibreglass as sold by Dow
Corning of Corning, N.Y. In an alternate embodiment, the glassy
fibre is basalt based.
[0058] In a preferred embodiment, the beam wrapping 109 is a woven
mat having about the same quantity of fibres 139 extending in each
of two generally orthogonal directions (i.e., approximately 50% of
the fibres 139 running in each direction). This is achieved by
wrapping the beam wrapping 109 on a bias relative to the beam axis
107.
[0059] The beam 105 is further wrapped with wire strands 111. In a
preferred embodiment, the wire strands 111 are incorporated in the
beam wrapping 109. Alternately, the wire strands 111 may be an
element of an additional wire strand wrap 141, which is applied
over top the beam wrapping 109. In either case, the wire strands
111 run generally parallel to the beam axis 107 (FIG. 14).
[0060] The wire strands 111 are comprised of steel. In a preferred
embodiment, the wires 111 are comprised of high tensile strength
steel.
[0061] Referring to FIGS. 8(b) and 12, a beam end portion 137 is
illustrated according to a preferred embodiment of the present
invention. The beams 105 are comprised of wood, with each of the
beams being made up of a plurality of laminae 143 having adjacent
faces 145 laminated together and having a grain 147 running along
the beam axis 107. In a preferred embodiment, the laminae 143 are
aligned with the adjacent faces 145 generally parallel to the upper
face 149 of the panel 100.
[0062] In a preferred embodiment, the wood laminate beam 105 is
comprised of kiln dried spruce, which provides a high tensile
strength per unit weight. The wood laminae 143 are dried to
approximately 16% moisture or less and fixed to each other using an
adhesive. In a preferred embodiment, the adhesive is manufactured
by Borden Chemical Ltd. of Montreal, Canada, although any adhesive
known to those skilled in the art that is as strong as or stronger
than the wood may be employed.
[0063] In an alternate embodiment, the panel 100 may be used in low
stress or low load bearing applications, such as a wall panel. The
load bearing capabilities and weight of a panel 100 that
incorporates wood laminate beams may be neither required, nor
desired. The beams 105 may be comprised of a low density material,
such as a foam material, which is both light weight and able to
bear a load. Any low density material that can bear a load, which
is known to those skilled in the art, may be employed.
[0064] Referring to FIGS. 8(a) and (b), the frame 101, beam
wrapping 109, beams 105 and wire strands 111 are further wrapped
and surrounded by an outer layer of reinforcing fibres 113
comprised of mat reinforcing fibres 115, thereby creating a wrapped
structure. In a preferred embodiment, the reinforcing fibre 115 is
a glassy fibre, such as a standard fibre glass as sold by Dow
Corning of Corning, N.Y. In an alternate embodiment, the glassy
fibre is basalt based.
[0065] In a preferred embodiment, the outer fibre wrap 113 has
about 90% of its fibres extending longitudinally and generally
parallel to the frame axis 103. The relative ratio of the fibres
115 as well as the relative directions in which the fibres 115
extend may vary with the particular use to which the structural
member 100 is put and the direction and magnitude of the resultant
forces exerted on the structural panel 100. For example, if the
structural panel 100 is used as a roof panel, the fibres 115 may
extend equally in all directions. If the panel 100 is employed as a
bridge deck, then approximately 80% of the fibres 115 extend
longitudinally (generally parallel with the frame axis 103) and
approximately 20% of the fibres 115 run generally orthogonal to the
longitudinally extending fibres 115.
[0066] After the outer fibre mat 113 is applied, the wrapped
structure is permeated with and encased in an epoxy resin that
extends throughout the frame 101, beam 10 wrapping 109, beams 105,
wire strands 111 and outer wrap 113. The epoxy resin impregnates
the fibrous material and surrounds the frame 101 and plurality of
beams 105, ultimately undergoing a physical state transformation
from a low viscosity fluid to a rigid solid state and thereby
acting as a binding matrix of the fibrous material (109, 113),
frame 101 and plurality of beams 105 to create a final composite
material. In a preferred embodiment, the epoxy has exceptional
adherence (without the use of special primers) to steel, such as
the Jeffco 4101-08 epoxy resin and Jeffco 4101-18 epoxy hardener as
manufactured by Jeffco Ltd. of San Diego, Calif.
[0067] A vacuum assisted resin transfer method (V.A.R.T.) may be
used to encase the wrapped structure in epoxy resin, although any
other method of impregnating and encasing a wrapped structure that
is known to those skilled in the art may be used. The wire strands
111 act as a flow medium for the epoxy resin, thereby ensuring that
the resin sufficiently permeates and surrounds the wrapped
structure. The wire strands' 111 function as a flow medium for the
epoxy resin also obviates the need to cut flow channels into the
wrapped structure or any of its components.
[0068] The components of the panel 100 (i.e., the frame 101, beams
105, wraps 109 and 113, and epoxy 117) are selected to have
physical properties that do not vary to such a degree that
separation of the components of the composite panel occurs when the
panel 100 is in use; i.e., tensile and compressive forces exerted
on the panel 100 are distributed over the whole of the panel and no
one component of the panel 100 bears a disproportionate degree of
load bearing stress, which would result in separation of the panel
100 components.
[0069] Sample Applications
[0070] The structural panel 100 may be used in many different
applications, such as building panels, piles, floor panels, wall
panels, roof panels, box culverts and retaining walls. Referring to
FIG. 13, a preferred application of the structural panel 100 as a
bridge deck 500 is illustrated.
[0071] The bridge deck 500 has an upper face 501 that is coated in
a road surfacing material 503. In a preferred embodiment, the
coating 503 is a latex asphalt, such as manufactured by TJ Pounder
Inc. of Brampton, Ontario, Canada. Latex asphalt is preferred
because it can be applied cold, thereby obviating the need to apply
a hot asphalt mixture, which may potentially compromise the
structural integrity of the structural panel 100. A primer is
applied first to the upper surface and then an approximately
one-half inch (approximately 1.25 cm) layer of latex asphalt is
applied. The opposite face or underside 505 of the deck 500 is
painted with UV stabilised polyurethane.
[0072] The upper face 501 of the deck 500 is preferably canted with
a longitudinally extending centre section 507 higher than and
sloping toward opposite side edges 509 of the deck 500 to promote
drainage.
[0073] In a preferred embodiment, the deck 500 is thicker at the
opposite side edges 509 than at the centre section 507 thereby
providing a curb 511 at the side edges 509. Having a deck 500 with
curbs 511 at the opposite side edges 509 results in overall
enhanced stiffness of the deck 500, thereby allowing it to be
thinner at the centre section 507 than would be required of a panel
having the same load bearing capacity but of generally constant
thickness.
[0074] The present invention is defined by the claims appended
hereto, with the foregoing description being illustrative of the
preferred embodiments of the invention. Those of ordinary skill may
envisage certain additions, deletions and/or modifications to the
described embodiments, which, although not explicitly suggested
herein, do not depart from the scope of the invention, as defined
by the appended claims. For example, the beams may be of non
rectangular cross-sectional configuration (such as circular,
elliptical, triangular etc.) and the beams need not have their
respective longitudinal axes coplanar. Furthermore in some
applications curved rather than straight beams may be
desirable.
* * * * *