U.S. patent application number 10/858254 was filed with the patent office on 2004-11-04 for modular load bearing deck structure.
Invention is credited to Abrahamson, Eric, Dumlao, Chris, Fisher, Les, Lauraitis, Kristina, Miller, Alan.
Application Number | 20040216250 10/858254 |
Document ID | / |
Family ID | 24904832 |
Filed Date | 2004-11-04 |
United States Patent
Application |
20040216250 |
Kind Code |
A1 |
Dumlao, Chris ; et
al. |
November 4, 2004 |
Modular load bearing deck structure
Abstract
A load bearing support structure includes a load bearing support
and a load bearing deck. Such a support structure may be used in
the construction of a bridge.
Inventors: |
Dumlao, Chris; (Pleasanton,
CA) ; Lauraitis, Kristina; (San Jose, CA) ;
Fisher, Les; (Palo Alto, CA) ; Miller, Alan;
(Santa Cruz, CA) ; Abrahamson, Eric; (Palo Alto,
CA) |
Correspondence
Address: |
BARNES & THORNBURG
11 SOUTH MERIDIAN
INDIANAPOLIS
IN
46204
|
Family ID: |
24904832 |
Appl. No.: |
10/858254 |
Filed: |
June 1, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10858254 |
Jun 1, 2004 |
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10270186 |
Oct 15, 2002 |
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10270186 |
Oct 15, 2002 |
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09886219 |
Jun 22, 2001 |
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6467118 |
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09886219 |
Jun 22, 2001 |
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09495474 |
Feb 1, 2000 |
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09495474 |
Feb 1, 2000 |
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08723098 |
Sep 30, 1996 |
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6023806 |
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Current U.S.
Class: |
14/73 |
Current CPC
Class: |
E01D 19/125 20130101;
B63B 5/00 20130101; E04D 13/1656 20130101; E01D 2101/40
20130101 |
Class at
Publication: |
014/073 |
International
Class: |
E01D 019/12 |
Claims
1. A load bearing bridge comprising: a load bearing support, and a
bridge deck, the deck comprising at least one panel, the at least
one panel comprising: one or more members, each of said members
having at least four walls wherein at least one wall is a vertical
wall and at least one wall is disposed at an oblique angle to said
at least one vertical wall, such that said member, when viewed in
cross-section, defines a polygonal shape, and wherein at least a
portion of said bridge is formed of a polymer matrix composite
material comprising reinforcing fibers and a polymer resin.
2. The bridge according to claim 1, which the composite material is
formed by a method selected from the group consisting of
pultrusion, resin transfer molding, vacuum curing, and filament
winding.
3. The bridge as defined in claim 2, wherein the polymer matrix
composite material is formed by pultrusion.
4. The bridge as defined in claim 2, supported by at least one
support beam.
5. The bridge as defined in claim 1, wherein each of said members
has a wall positioned generally adjacent to one wall of an adjacent
member.
6. The bridge as defined in claim 1, wherein a plurality of said
members are aligned longitudinally in a direction of span of said
bridge deck.
7. The structure as defined in claim 1, wherein a plurality of said
core members are aligned transversely to the direction of span of
said bridge deck.
8. The bridge as defined in claim 1, wherein said members have a
polygonal cross-section that defines a trapezoid.
9. The bridge as defined in claim 1, wherein said members are
elongated substantially hollow members.
10. The bridge as defined in claim 1, wherein the members are
formed integrally by pultrusion.
11. The bridge as defined in claim 1, wherein a plurality of panels
form said deck.
12. The bridge as defined in claim 11, wherein said deck bears a
wear surface overlying an upper surface of the deck.
13. The bridge as defined in claim 1, wherein: the at least one
panel is formed at least in part of a pultruded polymer matrix
composite material, and each panel comprises a plurality of members
which form a trapezoid when viewed in cross-section, and wherein
each panel is adapted to be joined to an adjacent panel.
14. The bridge as defined in claim 13, which includes an upper wall
and a lower wall extending beyond the panel to define a receiving
opening for an adjacent panel.
15. The bridge as defined in claim 1, which includes an upper wall
and a lower wall extending beyond each panel to define a receiving
opening for an adjacent panel.
16. The bridge as defined in claim 1, wherein said at least one
panel is an integrally formed, unitary pultruded panel comprising
at least one pultruded member.
17. A bridge comprising: a load bearing deck; and a support for
supporting the load bearing deck; the load bearing deck comprising:
at least one member formed at least in part from a polymer matrix
composite material, the at least one member having at least four
walls, wherein each member comprises at least one vertical wall,
and at least one of the walls is disposed at an oblique angle to
the at least one vertical wall, such that the members define a
polygonal shape.
18. A bridge according to claim 17, wherein the support comprises
at least one beam.
19. A bridge according to claim 17, wherein the polygonal shape is
a trapezoid.
20. A bridge according to claim 19, wherein a plurality of members
are disposed in said deck in abutting relationship.
21. A bridge according to claim 17, wherein at least one of the
plurality of members is formed of a polymer matrix composite
material by pultrusion.
22. An integral load bearing deck structure comprising: an upper
surface; a lower surface; and a tube defined by the upper surface
and lower surface and integral thereto, each tube comprising a
polygonal shape of at least four walls including the upper surface
and lower surface when viewed in cross-section, and including at
least one vertical wall and at least one diagonal wall.
23. An integral load bearing deck structure according to claim 22,
wherein the polygonal shape is a trapezoid and the support
structure is a bridge deck.
24. An integral load bearing deck structure according to claim 23,
which include an upper wall and lower wall extending beyond said
polygonal shape to define a receiving opening.
25. A load bearing deck comprising: a least one panel formed of a
polymer matrix composite material, said panel comprising a member
having four walls, said members having two of opposed walls being
provided with a facesheet formed integrally with the walls of the
members, wherein at least one of the walls is disposed at an
oblique angle to one of the other walls such that the walls define
a polygonal shape when viewed in cross-section.
26. A deck according to claim 25, wherein the polygonal shape is a
trapezoid.
27. A deck according to claim 26, wherein at least two of said
members are positioned to abut one another to form the panel.
28. A deck according to claim 27, wherein at least two of said
walls extend beyond said polygonal shape to define a receiving
opening.
29. A deck according to claim 25, wherein at least two of said
members abut one another.
30. A deck according to claim 28, wherein said at least one panel
comprises a plurality of interconnected members.
31. A deck according to claim 25, wherein said at least one panel
is an integrally formed, unitary pultruded panel comprising
pultruded facesheets and at least one pultruded member.
32. A load bearing integral deck structure comprising: a composite
member having at least four walls defining a first closed polygonal
when viewed in cross section, said composite member having at least
an oblique member connecting two of said four walls dividing said
closed polygonal into at least a second and third closed polygonal
when viewed in cross section, said oblique member connecting one of
said four exterior walls to another of said four exterior walls at
other than an intersection of any of said four walls.
33. The structure of claim 32, wherein said first polygonal shape
is rectangular.
34. The structure of claim 33, wherein said second and third closed
polygonals are trapezoidal.
35. The structure of claim 34, wherein a series of said rectangular
polygonal shapes are aligned in abutting relationship to form said
load bearing structure.
36. A load bearing integral deck structure comprising: a member
having at least four exterior walls and an oblique member
connecting an interior of two of said four walls, said oblique
member together with said portions of said two connected walls and
one of said other walls defining a first and second closed
polygonal when viewed in cross section, said oblique member
connecting said two connected walls at other than an intersection
of any of said four walls.
37. A load bearing deck comprising: a first face sheet, a second
face sheet, two walls, each of said two walls extending
substantially perpendicular to and between the two face sheets, and
an oblique wall located between the two walls and the two face
sheets, the oblique wall dividing the space between the face sheets
and two walls into two hollow trapezoids.
38. A deck according to claim 37, wherein the face sheets and walls
are integral.
39. A deck according to claim 37, wherein the deck is a bridge
deck.
40. A deck according to claim 37, wherein the deck is a composite
structure.
41. A deck according to claim 37, wherein the deck is
pultruded.
42. A load bearing deck, comprising: a first face sheet, a second
face sheet, two walls, each of the two walls extending
substantially perpendicular to and between the two face sheets, and
an oblique wall located between the two face sheets and two walls,
positioned such that the oblique wall does not intersect an
intersection of a face sheet and a wall.
43. A deck according to claim 42, wherein the face sheets and walls
are integral.
44. A deck according to claim 42, wherein the deck is a bridge
deck.
45. A deck according to claim 42, wherein the deck is a composite
structure.
46. A deck according to claim 42, wherein the deck is pultruded.
Description
[0001] This application is a continuation of copending U.S. patent
application Ser. No. 10/270,186, filed on Oct. 15, 2002; which is a
continuation of U.S. patent application Ser. No. 09/886,219 (now
U.S. Pat. No. 6,467,118), filed on Jun. 22, 2001; which is a
continuation of U.S. patent application Ser. No. 09/495,474 (now
abandoned), filed on Feb. 1, 2000; which is a divisional of U.S.
patent application Ser. No. 08/723,098 (now U.S. Pat. No.
6,023,098), filed on Sep. 30, 1996, the entirety of each of which
is hereby incorporated by reference.
FIELD OF THE INVENTION
[0002] This invention relates to support structures such as
bridges, piers, docks, load bearing decking applications, such as
hulls and decks of barges, and load bearing walls. More
particularly, this invention relates to a modular composite load
bearing support structure including a polymer matrix composite
modular structural section for use in constructing bridges and
other load bearing structures and components.
BACKGROUND OF THE INVENTION
[0003] Space spanning structures such as bridges, docks, piers,
load bearing walls, hulls, and decks which have provided a span
across bodies of water or separations of land and water and/or open
voids have long been made of materials such as concrete, steel or
wood. Concrete has been used in building bridges, and other
structures including the columns, decks, and beams which support
these structures.
[0004] Such concrete structures are typically constructed with the
concrete poured in situ as well as using some preformed components
precast into structural components, such as supports, and
transported to the site of the construction.
[0005] Constructing such concrete structures in situ requires
hauling building materials and heavy equipment and pouring and
casting the components on site. This process of construction
involves a long construction time and is generally costly, time
consuming, subject to delay due to weather and environmental
conditions, and disruptive to existing traffic patterns when
constructing a bridge on an existing roadway.
[0006] On the other hand, pre-cast concrete structural components
are extremely heavy and bulky and are typically costly and
difficult to transport to the site of construction due in part to
their bulkiness and heavy weight. Although construction time is
shortened compared to construction with concrete poured in situ,
extensive construction time with resulting delays is still a
factor. Bridge construction with such precast forms is particularly
difficult, if not impossible, in remote or difficult terrain such
as mountains or jungle areas in which numerous bridges are
constructed.
[0007] In addition to construction and shipping difficulties with
concrete bridge structures, the low tensile strength of concrete
can result in failures in concrete bridge structures, particularly
in the surface of bridge components. Reinforcement is often
required in such concrete structures when subjected to large loads
such as in highway bridges. Steel and other materials have been
used to reinforce concrete structures. If not properly installed,
such reinforcements cause cracking and failure in the reinforced
concrete, thereby weakening the entire structure. Further, the
inherent hollow spaces which exist in concrete are highly subject
to environmental degradation. Also, poor workmanship often
contributes to the rate of deterioration.
[0008] In addition to concrete, steel also has been widely used by
itself as a building material for structural components in
structures such as bridges, barge decks, vessel hulls, and load
bearing walls. While having certain desirable strength properties,
steel is quite heavy and costly to ship and can share construction
difficulties with concrete as described.
[0009] Steel and concrete are also susceptible to corrosive
elements, such as water, salt water and agents present in the
environment such as acid rain, road salts, chemicals, oxygen and
the like. Environmental exposure of concrete structures leads to
pitting and spalling in concrete and thereby results in severe
cracking and a significant decrease in strength in the concrete
structure. Steel is likewise susceptible to corrosion, such as
rust, by chemical attack. The rusting of steel weakens the steel,
transferring tensile load to the concrete, thereby cracking the
structure. The rusting of steel in stand alone applications
requires ongoing maintenance, and after a period of time corrosion
can result in failure of the structure. The planned life of steel
structures is likewise reduced by rust.
[0010] The susceptibility to environmental attack of steel requires
costly and frequent maintenance and preventative measures such as
painting and surface treatments. In completed structures, such
painting and surface treatment is often dangerous and time
consuming, as workers are forced to treat the steel components in
situ while exposed to dangerous conditions such as road traffic,
wind, rain, lightning, sun and the like. The susceptibility of
steel to environmental attack also requires the use of costly
alloys in certain applications.
[0011] Wood has been another long-time building material for
bridges and other structures. Wood, like concrete and steel, is
also susceptible to environmental attack, especially rot from
weather and termites. In such environments, wood encounters a
drastic reduction in strength which compromises the integrity of
the structure. Moreover, wood undergoes accelerated deterioration
in structures in marine environments.
[0012] Along with environmental attack, deterioration and damage to
bridges and other traffic and load bearing structures occurs as a
result of heavy use. Traffic bearing structures encounter repeated
heavy loads of moving vehicles, stresses from wind, earthquakes and
the like which cause deterioration of the materials and
structure.
[0013] For the reasons described above, the United States
Department of Transportation "Bridge Inventory" reflects several
hundred thousand structures, approximately forty percent of bridges
in the United States, made from concrete, steel and wood are poorly
maintained and in need of rehabilitation in the United States. The
same is believed to be true for other nations.
[0014] The associated repairs for such structures are extremely
costly and difficult to undertake. Steel, concrete and wood
structures need welding, reinforcement and replacement. Decks and
hulls of structures in marine environments rust, requiring constant
maintenance and vigilance. In numerous instances, these necessary
repairs are not feasible or economically justifiable and cannot be
undertaken, and thereby require the replacement of the structure.
Further, in developing areas where infrastructures are in need of
development or improvement, those constructing bridges and other
such structures utilizing concrete, steel and wood face unique
difficulties. Difficulty and high cost has been associated with
transporting materials to remote locations to construct bridges
with concrete and steel. This process is more costly in marine
environments where repairs require costly dry-docking or transport
of materials. Also, the degree of labor and skill is very high
using traditional building materials and methods.
[0015] Further, traditional construction methods have generally
taken long time periods and required large equipment and massive
labor costs. Thus, development and repair of infrastructures
through the world has been hampered or even precluded due to the
cost and difficulty of construction. Further, in areas where
structures have been damaged due to deterioration or destroyed by
natural disaster such as earthquake, hurricane, or tornado, repair
can be disruptive to traffic or use of the bridge or structure or
even delayed or prevented due to construction costs.
[0016] In addressing the limitations of existing concrete, wood and
steel structures, some fiber reinforced polymer composite materials
have been explored for use in constructing parts of bridges
including foot traffic bridges, piers, and decks and hulls of some
small vessels. Fiber reinforced polymers have been investigated for
incorporation into foot bridges and some other structural uses such
as houses, catwalks, and skyscraper towers. These composite
materials have been utilized, in conjunction with, and as an
alternative to, steel, wood or concrete due to their high strength,
light weight and highly corrosion resistant properties. However, it
is believed that construction of traffic bridges, marine decking
systems, and other load bearing applications built with polymer
matrix composite materials have not been widely implemented due to
extremely high costs of materials and uncertain performance,
including doubts about long term durability and maintenance.
[0017] As cost is significant in the bridge construction industry,
such materials have not been considered feasible alternatives for
many load bearing traffic bridge designs. For example, high
performance composites made with relatively expensive carbon fibers
have frequently been eliminated by cost considerations. These same
cost considerations have inhibited the use of composite materials
in decking and hull applications.
[0018] In investigating providing structural components made from
fiber reinforced polymer composite materials, components structures
from prior materials such as steel, concrete and wood have been
investigated. Steel trusses and supports have utilized triangular
shapes welded together. Providing triangular structural components
with composite materials has presented problems of failure in the
resin bonded nodes of the triangular shape. Therefore a modular
structural composite component for structural supports is needed
which overcomes this problem.
[0019] In view of the problems associated with bridges and other
structures formed of steel, concrete, and wood described herein,
there remains a need for a bridge or like support structure with
the following characteristics: light-weight; low cost,
pre-manufactured; constructed of structural modular components;
easily shipped, constructed, and repaired without requiring
extensive heavy machinery; and resistant to corrosion and
environmental attack, even without surface treatment. There is also
a need for a support structure which can provide the structural
strength and stiffness for constructing a highway bridge or similar
support structure.
SUMMARY OF THE INVENTION
[0020] In view of the foregoing, it is therefore an object of the
present invention to provide a load bearing support structure
suitable for a highway bridge structure or decking system in marine
and other construction applications, constructed of modular
structural sections formed of a lightweight, high performance,
environmentally resistant material.
[0021] It is another object of the invention to provide a support
structure such as a highway bridge structure which satisfies
accepted design, performance, safety and durability criteria for
traffic bearing bridges of various types.
[0022] It is another object of the present invention to provide
such a support structure in the form of a traffic-bearing bridge in
a variety of designs and sizes constructed of modular structural
sections which can be constructed quickly, cost-effectively and
with limited heavy machinery and labor.
[0023] It is also an object of the present invention to provide
such a support structure, such as a bridge, constructed of
components which can easily and cost-effectively be shipped to the
site of construction as a complete kit.
[0024] It is likewise an object of the present invention to provide
a support structure including a modular structural section which
can be utilized to quickly repair or replace a damaged bridge,
bridge section or like support structure.
[0025] It is another object of the present invention to provide a
load bearing support structure including a modular structural
section which can be used in decking, hull, and wall
applications.
[0026] It is still another object of the invention to provide a
support structure or bridge which requires minimal maintenance and
upkeep with respect to surface treatment or painting.
[0027] These and other objects, advantages and features are
satisfied by the present invention, which is directed to a polymer
matrix composite modular load bearing support structure described
herein for exemplary purposes in the form of a highway bridge. The
support structure of the present invention includes a plurality of
support members and at least one modular structural section
positioned on and supported by the support members. The modular
structural section is preferably formed of a polymer matrix
composite.
[0028] The modular structural section includes at least one beam
and a load bearing deck positioned above and supported by the beam.
The at least one beam includes a pair of lateral flanges and a
medial web between and extending below the flanges. In one
embodiment, the flanges and the web have a predetermined shape
which matably contacts surfaces of support means which also have a
predetermined contoured shape. The flanges and web are positioned
on and supported the contoured shaped support means. In a preferred
embodiment, the lateral flanges and the web also preferably form a
U-shaped cross-section having a generally flat floor in the medial
portion.
[0029] In an alternative embodiment, the flat floor of the elongate
support can be positioned on and supported by support means having
a surface having a generally flat portion preferably-a support
member or abutment with a flat cap portion.
[0030] In a further alternative embodiment, the support means in
the form of a support member or abutment can be provided having a
surface having a horizontal cap surface perpendicular to a vertical
wall surface forming an L-shape surface for supporting the beam and
deck of the modular structural section. The beam is preferably
positioned, in this embodiment with the flat floor positioned above
the horizontal cap surface and the end edge of the web and flanges
of the modular structural section positioned flush with the
vertical wall surface.
[0031] In all of these embodiments, the polymer matrix composite
support structure of the present invention can provide a support
surface sufficient to support vehicular traffic and to conform to
established design and performance criteria.
[0032] Alternatively, the modular structural section, including the
load-bearing deck and beam, can be used in constructing other
support structures including space-spanning support structures.
Further, the load bearing deck can also be used as a stand alone
decking, hull, or wall system which can be integrated into a marine
or construction system. The load bearing decking system can be
utilized in numerous applications where load bearing decking, hulls
and walls are required.
[0033] The support structure also reduces tooling and fabrication
costs. The support structure is easy to construct utilizing
prefabricated components which are individually lightweight, yet
structurally sound when utilized in combination. The modularity of
the components enhances portability, facilitates pre-assembly and
final positioning with light load equipment, and reduces the cost
of shipping and handling the structural components. The support
structure allows for easy construction of structures such as, but
not limited to, bridges, marine decking applications and other
construction and transportation applications.
[0034] The load bearing deck of the modular structural section also
includes at least one sandwich panel including an upper surface, a
lower surface and a core. The core includes a plurality of
substantially hollow, elongated core members positioned between the
upper surface and the lower surface. Each of the elongate core
members includes a pair of side walls. The side walls can be formed
and disposed in a variety of shapes angles with respect to the
upper and lower walls. Each core member has side walls positioned
generally adjacent to a side wall of an adjacent core member. The
upper and lower surfaces of the sandwich panel are preferably an
upper facesheet and lower facesheet formed of a polymer matrix
composite material. In one embodiment, the upper and lower
facesheets are formed of polymer matrix composite arranged in a
hybrid of alternating layers including carbon and E-glass fibers in
vinylester or polyester resin.
[0035] In one embodiment of the bridge described herein for a 30
foot span highway bridge, the individual components including the
beams and the sandwich panels for the deck of the modular
structural section each weigh less than 3600 pounds. Being
constructed of a number of modular structural sections including
components manufactured from polymer matrix composites, instead of
concrete, steel and wood, the bridge has individual modular
components which are fault tolerant in manufacture, as twisting and
small warpage can be corrected at assembly. These properties of the
bridge components decrease the cost of manufacture and assembly for
the bridge. These components, including lightweight-modular
structural sections manufactured under controlled conditions, also
allow for low cost assembly of a number of applications, such as
marine structures, including the various applications described
herein.
[0036] Another aspect of the present invention is a method of
constructing a support structure such as highway bridge. The method
comprises the following steps. First, a plurality of spaced-apart
support members having a predetermined shape, for example a
contoured shape, are provided. Next, a modular structural section
is positioned on the plurality of spaced-apart support members. In
one embodiment, the elongate support members of the modular
structural section have a contoured shape which matably joins with
and is supported on the contoured shape of support members. The
modular structural section and the support members are then in
various embodiment connected.
[0037] In one embodiment, the modular structural section is
positioned by: first, positioning the beam having a contoured shape
upon adjacent of the support members having a contoured shape for
matably joining with and supporting the beam; then positioning the
load bearing deck upon the beam, then connecting the at least one
beam with the deck.
[0038] In another embodiment, a load bearing pad is first
positioned on a flat cap portion of a support member. Then, the
modular structural section is positioned on the load bearing pad
with the flat floor of the beam positioned on the load bearing
pad.
[0039] The methods of the present invention provide significantly
reduced time, labor and cost as compared to conventional methods of
bridge and support structure construction utilizing concrete, wood
and metal structures.
BRIEF DESCRIPTION OF THE-DRAWINGS
[0040] FIG. 1 is a perspective view of a load bearing support
structure in the form of a traffic highway bridge according to the
present invention and a truck traveling thereon.
[0041] FIG. 2 is a cutaway partial perspective view of a modular
structural section of the bridge according to the present
invention.
[0042] FIG. 3 is an exploded view of a sandwich panel deck of FIG.
2 having trapezoidal core members.
[0043] FIG. 4 is an exploded perspective view of a plurality of
contoured beams positioned on contoured support members of the
bridge of FIG. 2.
[0044] FIG. 5 is an exploded perspective view of the sandwich panel
deck being positioned on the beams of the bridge of FIG. 2.
[0045] FIG. 6 is an end view of the modular structural section of
the bridge of FIG. 2 showing a support diaphragm positioned in the
end thereof.
[0046] FIG. 7 is an enlarged cross-sectional view of adjacent
panels of the sandwich deck of FIG. 2 being joined with a key
lock.
[0047] FIG. 8 is a cross-section, exploded view of the facesheets
of the modular structural section.
[0048] FIG. 9 is a perspective view of an alternative embodiment of
a load bearing support structure in the form of a traffic highway
bridge having a flat support member according to the present
invention and a truck traveling thereon.
[0049] FIG. 10 is an exploded partial perspective view of a modular
structural section of the bridge of FIG. 9 according to the present
invention.
[0050] FIG. 11 is a perspective view of an alternative embodiment
of a load bearing support structure in the form of a traffic
highway bridge having a L-shape support member according to the
present invention and a truck traveling thereon.
[0051] FIG. 12 is an exploded partial perspective view of a modular
structural section of the bridge of FIG. 11 according to the
present invention.
[0052] FIG. 13 is a perspective view of an alternative embodiment
of a load bearing support structure in the form of a traffic
highway bridge having a flat support member according to the
present invention and a truck traveling thereon.
[0053] FIG. 14 is an exploded partial perspective view of a modular
structural section of the bridge of FIG. 13 according to the
present invention.
[0054] FIG. 15 is a perspective view of an alternative embodiment
of a load bearing support structure in the form of a traffic
highway bridge having a L-shape support member according to the
present invention and a truck traveling thereon.
[0055] FIG. 16 is an exploded partial perspective view of a modular
structural section of the bridge of FIG. 11 according to the
present invention.
[0056] FIG. 17 is an exploded perspective view of the modular
structural section of the bridge of FIG. 2 showing an alternative
embodiment of support diaphragms positioned in the end thereof.
[0057] FIG. 18 is an exploded perspective view of the modular
structural section of the bridge of FIG. 2 showing an alternative
embodiment of a support diaphragm positioned on the end
thereof.
[0058] FIG. 19 is an exploded perspective view of the modular
structural section of the bridge of FIG. 2 showing an alternative
embodiment of a support diaphragm positioned on the end
thereof.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0059] The present invention now will be described more fully
hereinafter with reference to the accompanying drawings, in which
preferred embodiments of the invention are shown. This invention
can, however, be embodied in many different forms and should not be
construed as limited to the embodiments set forth herein; rather,
Applicant provides these embodiments so that this disclosure will
be thorough and complete, and will fully convey the scope of the
invention to those skilled in the art.
[0060] Referring now to the figures, a modular composite support
structure in the form of a bridge structure 20 according to the
present invention is shown. This embodiment of the bridge 20 is
designed to exceed standards for bridge construction such as
American Association of State Highway and Transportation Officials
(AASHTO) standards. The AASHTO standards include design and
performance criteria for highway bridge structures. The AASHTO
standards are published in "Standard Specifications for Highway
Bridges," American Association of State Highway and Transportation
Officials, Inc., (15th Ed., 1992) which is hereby incorporated by
reference in its entirety. Support structures, including bridges,
of the present invention can be constructed which meet other
structural, design and performance criteria for other types of
bridges, construction and transportation support structures, and
other applications including, but not limited to, road bearing
decking systems and marine applications.
[0061] The support structure is described with reference to a
traffic-bearing highway bridge herein. As shown in FIGS. 1 and 2,
the bridge 20 is a simply-supported highway bridge capable of
withstanding loads from highway traffic such as the truck T. The
bridge 20 has a span defined by the length of the bridge 20 in the
direction of travel of truck T. The bridge 20 comprises a modular
structural section 30 including a deck 32 and beams 50, 50', 50"
and a deck 32 supported on and connected with the beams 50, 50',
50" (FIG. 2). The modular structural section 30 is supported on
support members 22.
[0062] In addition to a simply-supported bridge, alternatively, the
bridge including the modular structural section according to the
present invention can be provided in other types of bridges
including lift span bridges, cantilever bridges, cable suspension
bridges, suspension bridges and bridges across open spaces in
industrial settings. Various spans of bridges can be provided
including, but not limited to, short, medium and long span bridges.
The bridge technology can also be supplied for bridges other than
highway bridges such as foot bridges and bridge spans across open
spaces in industrial settings. Other space spanning support
structures can also be constructed in a similar manner to that
indicated including, but not limited to, bridge component
maintenance (replacement decking, column/beam supports, abutments,
abutment forms and wraps), marine structures (walkways, decking
(small/large scale)), load bearing decking systems, drill
platforms, hatch covers, parking decks, piers and fender systems,
docks, catwalks, super-structure in processing and plants with
corrosive environments and the like which provide an elevated
support surface over a span, rail cross ties, space frame
structures (conveyors and structural supports) and emission stack
liners. Other structures such as railroad cars, shipping
containers, over-the-road trailers, rail cars, barges and vessel
hulls could also be constructed in a similar manner to that
indicated. The components of the bridge 20, including the modular
structural section 30 and constituent deck 32 and beam 50, as
described herein, can also be provided, individually and in
combination, in such other support structures as described.
[0063] The support members 22, in this embodiment, have a
predetermined contoured shape configured to matably contact and
join with the predetermined shape of the beams 50, 50', 50". The
support members each have a plurality of spaced-apart peak portions
23 and a plurality of spaced apart trough portions 25 positioned
adjacent to and between said peak portions 23 (FIG. 2). The peak
portions 23 and the trough portions 25 are generally flat to
matably contact and support the beams 50, 50', 50". The column peak
portions 23 and the trough portions 25 are arranged and spaced
apart a predetermined distance to facilitate supporting the beams
50, 50', 50".
[0064] Each of the beams 50, 50', 50" have flanges 51, 52 which are
positioned on the peak portions 23 of the support members 22. Each
of the beams 50, 50', 50" also have a medial web 53 between and
extending below the flanges 51, 52. As shown in FIGS. 5 and 6 the
medial web 53 includes a inclined sidewall 54 and a generally flat
floor 68. The trough portion 25 of the support members 22 supports
the medial web 53 including the inclined side walls 54 and the flat
floor 68. In the bridge 20 of FIG. 1, the support members are
positioned at opposite ends 55, 56 of the beams 50. Alternatively,
the beams 50 can be supported by support members at intermediate
positions along the length of the beam 50.
[0065] The support members can be provided in various other shapes
and configurations, including other contoured shapes which are
configured to correspond to the shape of the beams 50. In other
alternative embodiments, the support members or other support means
can include the supports of an existing bridge replaced by the
bridge 20 of the present invention. Alternative embodiments of the
support members can be formed of other materials such as composite
materials, steel, wood or other materials. Further, alternative
embodiments of the support members are shown in applications to the
common assignee of this application entitled "MODULAR COMPOSITE
SUPPORT STRUCTURE AND METHODS OF CONSTRUCTING SAME", filed
concurrently, Ser. No. ______, (Attorney Docket No. 8637-5) and
entitled "MODULAR COMPOSITE SUPPORT STRUCTURE AND METHODS OF
CONSTRUCTING SAME", filed concurrently, Ser. No. ______, (Attorney
Docket No. 8637-88) (hereinafter "Modular Composite Support
Structure applications") the disclosure of which is hereby
incorporated by reference in its entirety. Additional support means
depend on the type of support structure constructed.
[0066] In the embodiment of FIGS. 1-5 and 7, the support members
22, and the modular structural section 30, including the deck 32
and beams 50 are formed of a polymer matrix composite comprising
reinforcing fibers and a polymer resin. Suitable reinforcing fibers
include glass fibers, including but not limited to E-glass and
S-glass, as well as carbon, metal, high modulus organic fibers
(e.g., aromatic polyamides, polybenzamidazoles, and aromatic
polyimides), and other organic fibers (e.g., polyethylene and
nylon). Blends and hybrids of the various fibers can be used. Other
suitable composite materials could be utilized including whiskers
and fibers such as boron, aluminum silicate and basalt.
[0067] The resin material in the support members 22 and the modular
structural section 30, including the deck 32 and the beams 50, 50',
50", are preferably a thermosetting resin, and more preferably a
vinyl ester resin. The term "thermosetting" as used herein refers
to resins which irreversibly solidify or "set" when completely
cured. Useful thermosetting resins include unsaturated polyester
resins, phenolic resins, vinyl ester resins, polyurethanes, and the
like, and mixtures and blends thereof. The thermosetting resins
useful in the present invention may be used alone or mixed with
other thermosetting or thermoplastic resins. Exemplary other
thermosetting resins include epoxies. Exemplary thermoplastic
resins include polyvinylacetate, styrene-butadiene copolymers,
polymethylmethacrylate, polystyrene, cellulose acetatebutyrate,
saturated polyesters, urethane-extended saturated polyesters,
methacrylate copolymers and the like.
[0068] Polymer matrix composites can, through the selective mixing
and orientation of fibers, resins and material forms, be tailored
to provide mechanical properties as needed. These polymer matrix
composite materials possess high specific strength, high specific
stiffness and excellent corrosion resistance. In the embodiment
shown in FIGS. 1-5 and 7, a polymer matrix composite material of
the type commonly referred to as a fiberglass reinforced polymer
(FRP) or sometimes, as glass fiber reinforced polymer (GFRP) is
utilized in the support members 22, deck 32 and the beams 50, 50',
50". The reinforcing fibers of the support members 22 and the
modular structural section 30, including the deck 32 and the beams
50, 50', 50", are glass fibers, particularly E-glass fibers, and
the resin is a vinylester resin. Glass fibers are readily available
and low in cost. E-glass fibers have a tensile strength of
approximately 3450 MPa (practical). Higher tensile strengths can
alternatively be accomplished with S-glass fibers having a tensile
strength of approximately 4600 MPa (practical). Polymer matrix
composite materials, such as a fiber reinforced polymer formed of
E-glass and a vinylester resin have exceptionally high strength,
good electrical resistivity, weather and corrosion-resistance, low
thermal conductivity, and low flammability.
[0069] The support members 22 are preferably formed of fiberglass
fibers in a vinylester resin. Alternatively, the support members 22
can be formed of other polymer matrix composite materials, as
described herein, or other materials such as concrete in precast
footings or poured in situ, steel, wood or other building
materials. An alternative embodiment of the support member 122
shown in FIG. 6 is a pre-cast concrete footing having the contoured
shape of the previously described support member 22.
[0070] The Deck
[0071] In the bridge 20 including the modular structural section 30
shown in FIGS. 1-2, the deck 32 includes three sandwich panels 34,
34' 34". Alternatively, any number of panels can be utilized in a
deck depending on the length of the desired span. As shown in FIG.
3, each sandwich panel 34 comprises an upper surface shown as an
upper facesheet 35, a lower surface shown as a lower facesheet 40
and a core 45 including a plurality of elongate core members
46.
[0072] The core members 46 are shown as hollow tubes of trapezoidal
cross-section (FIGS. 2, 3 and 7). Each of the trapezoidal tubes 46
includes a pair of side walls 48, 49. One of the side walls 48 is
disposed at an oblique angle .alpha. to one of the upper and lower
facesheets 35, 40 such that the side walls 48, 49 and the upper
wall 64 and lower wall 65, when viewed in cross-section, define a
polygonal shape such as a trapezoidal cross-section (FIG. 3). The
oblique angle .alpha. of the side wall 48 with respect to the upper
wall 64 is preferably about 45.degree., but angles between about
30.degree. and 45.degree. can be provided in alternative
embodiments. Each tube 46 has a side wall 48 positioned generally
adjacent to a side wall 48' of an adjacent tube 46' (FIG. 3).
Alternatively, the tubes 46 could be aligned in other
configurations such as having a space between adjacent side
walls.
[0073] The side walls 48, 48' disposed at an oblique angle .alpha.
provide transverse shear stiffness for the deck core 45. This
increases the transverse bending stiffness of the overall deck 32.
The sidewall 48 shown at the preferred 45.degree. angle .alpha.
provides the highest bending stiffness. The trapezoidal tubes 46
also preferably have a vertical side wall 49 positioned between
adjacent diagonal side walls 48, 48'. The vertical sidewall 49
provides structural support for localized loads subjected on the
deck 32 to prevent excessive deflection of the top facesheet 35
along the span between the intersection of the diagonal walls 48,
48' and the upper facesheet 35.
[0074] Thus, the shape including the angled side wall 48 of the
trapezoidal tube 46 provides stiffness across the cross-section of
the tube 46. An adjacent tube 46' includes a side wall 48' angled
in an opposite orientation between the upper and lower walls 64, 65
from the adjacent angled side wall 48. Providing side walls 48, 49
at varying orientations preserves the mathematical symmetry of the
cross-section of the tubes 46. When normalized by weight, the
trapezoidal tube 46 with at least a 45.degree. angle between the
sidewall 48 and the upper wall 64 and the lower wall 65 has a
transverse shear stiffness 2.6 times that of a tube with a square
cross-section. Alternatively, for a tube with an oblique angle of
about 30.degree., the transverse shear stiffness is 2.2 times that
of a tube with a square shaped cross-section.
[0075] The span between the diagonal side walls 48, 48' and the
vertical sidewall 49 can be provided in a variety of predetermined
distances. A variety of sizes, shapes and configurations of the
elongate core members can be provided. Various other polygonal
cross-sectional shapes can also be employed, such as
quadrilaterals, parallelograms, other trapezoids, pentagons, and
the like. Alternative embodiments to the tubes 46 can be seen in
the related Modular Composite Support Structure applications
referenced previously.
[0076] As explained, adjacent tubes 46 of the core 45 have adjacent
side walls 48, 48' aligned with one another (FIG. 3). The elongate
tubes 46 extend in their lengthwise direction preferably in the
direction of the span of the bridge (FIG. 1). Alternatively,
depending on design load parameters, the tube 46 can be positioned
to extend transverse to the direction of travel as seen in the
commonly assigned "Modular Composite Support Structure" application
referenced previously. Further, alternatively, tubes and other
polygonal core members of a variety of lengths and cross-sectional
heights and width dimensions can be provided in forming a deck of
the modular structural section according to the present
invention.
[0077] The tubes 46 are also preferably formed of a polymer matrix
composite material comprising reinforcing fibers and a polymer
resin. Suitable materials are the same polymer matrix composite
materials as previously discussed herein, the discussion is hereby
incorporated by reference. The tubes 46, are most preferably
E-glass fibers in a vinylester resin (FIG. 3).
[0078] The tubes 46 can be fabricated by pultrusion, hand lay-up or
other suitable methods including resin transfer molding (RTM),
vacuum curing and filament winding, automated layup methods and
other methods known to one of skill in the art of composite
fabrication and are therefore not described in detail herein. The
details of these methods are discussed in Engineered Materials
Handbook, Composites, Vol. 1, ASM International (1993).
[0079] When fabricating by hand lay-up, the tubes 46 can be
fabricated by bonding a pair of components. (not shown). One
component includes the vertical side wall 49 and a portion of the
upper wall 64 and lower wall 65. The other component includes the
angled side wall 48 and the respective remaining portions of the
upper wall 64 and lower wall 65. The upper and lower walls 64, 65
are bonded with an adhesive along the upper wall 64 and lower wall
65 where stresses are reduced.
[0080] It is believed that such forming overcomes the problem of
node failure experienced in forming triangular shapes with
composite materials. In a triangular section, the members behave as
a pinned truss. Such a truss system transfers load directly through
the vertex. To do so the truss encounters large amounts of
interlaminar shear and tensile stresses. The trapezoidal tube 46
does not experience forces at a vertex such as those in a
triangular section. The trapezoidal section of the tube 46 requires
that the load be carried partially by bending the cross-section.
Such bending relieves the interlaminar stresses resulting in a
higher load carrying capacity.
[0081] Also, as described above, the sandwich panels 34 each also
have an upper surface shown as an upper facesheet 35 and a lower
surface shown as facesheet 40 (FIG. 3). The tubes 46 are-sandwiched
between a lower surface 36 of the upper facesheet 35 and the upper
surface 41 of the lower facesheet 40. As seen in FIG. 3, the lower
face sheet 40 and the upper face sheet 35 are sheets preferably
formed of polymer matrix composite materials as described
herein.
[0082] Having fabricated the upper and lower facesheets 35, 40 as
described herein, the lower surface 36 of the upper face sheet 35
is preferably laminated or adhered to the upper surface 47 of the
tubes 46 by a resin 26 and/or other bonding means and joined with
the tubes 46 by mechanical or fastening means including, but not
limited to, bolts or screws. Likewise, the upper surface 41 of the
lower facesheet 40 is preferably laminated to the lower surface 27
of the tubes 46 by resin 26 or other bonding means and joined with
the tubes 46 by mechanical fastening means including, but not
limited to, bolts or screws.
[0083] The core 45, including the tubes 46, and the upper and lower
facesheets 35, 40, can be alternatively joined with fasteners
alone, including bolts and screws, or by adhesives or other bonding
means alone. Suitable adhesives include room temperature cure
epoxies and silicones and the like. Further, alternatively, the
tubes could be provided integrally formed as a unitary structural
component with an upper and lower surface such as a facesheet by
pultrusion or other suitable forming methods.
[0084] As described, the sandwich panels 34, 34', 34" of the deck
32, being formed of polymer matrix composite material, provide high
through thickness, stiffness and strength to resist localized wheel
loads of vehicles traveling over the bridge according to
regulations such as those promulgated by AASHTO.
[0085] In the deck shown in FIGS. 1-5 and 7-8, the upper and lower
facesheets 35, 40 are hand laid of polymer matrix composite
material. Alternatively, the facesheets 35, 40 can be fabricated
using automated layup methods. The upper and lower facesheets 35,
40 are each formed of a plurality of substrate layers 61, 62 (in
FIG. 8). Alternating layers of the substrate layers of the
facesheets 35, 40 are preferably formed of different reinforcing
fibers and a polymer resin.
[0086] Each of the facesheets 35, 40 shown in the embodiment of the
deck 32 of FIG. 3 are formed of a hybrid of glass and carbon
fibers, both with vinylester or alternatively polymer resin. The
facesheets 35, 40 each have an outer layer 60 formed of
quasi-isotropic E-glass and a vinylester and an adjacent layer 61
formed of graphite and vinylester (FIG. 8). The layers then
alternate between E-glass 62, 62' and carbon 61' as shown in FIG.
8.
[0087] The outer layers 60, 63 forming the upper and lower surfaces
of each facesheet 35, 40 are each formed of E-glass to provide
impact resistance. The layup was determined with a percentage of
graphite having the same stiffness as an all E-glass and
vinylester. The facesheets 35, 40 have a layup of approximately 42
percent graphite and 58 percent E-glass. Alternatively, other types
and combinations of composite materials can be used to fabricate
the upper and lower facesheets 35, 40 developing on the design
criteria. For example, facesheets 35, 40 formed of all glass fibers
can be provided in alternative embodiments.
[0088] The quasi-isotropic layup of the upper and lower facesheets
35, 40 prevent warping from non-uniform shrinkage during
fabrication. The orientation of the facesheets also provides a
nearly uniform stiffness in all directions of the facesheets 35,
40.
[0089] Alternatively, other types of composite materials, with
varying orientations, can be used to fabricate the upper and lower
facesheets 35, 40. For example., alternatively, the facesheets can
be formed with orientations other than quasi-isotropic layup.
Alternative configurations and compositions of facesheets 35, 40
can be seen in the commonly assigned Modular Composite Support
Structure applications referenced previously.
[0090] The upper and lower facesheets 35, 40 are fabricated in the
present embodiment by the following steps. First, the lower
facesheets 40 and upper facesheets 35 are fabricated by hand layup
using rolls of knitted quasi-isotropic fabric. The fibers of the
upper and lower facesheets 35, 40 are given a predetermined
orientation such as described depending on the desired
properties.
[0091] While the upper and lower facesheets 35, 40, are fabricated
using a hand-layup process, the core 45 including the facesheets
35, 40 can alternatively be fabricated by other methods such as
pultrusion, resin transfer molding (RTM), vacuum curing and
filament winding and other methods known to one of skill in the art
of composite fabrication, which, therefore, are not discussed in
detail herein. Further, facesheets and core members alternatively
can be fabricated as a single component such as by pultruding a
single sandwich panel having an upper and lower facesheet and a
core of tubes.
[0092] As shown in FIG. 3, a single upper face sheet 35 and a
single lower face sheet 40 can be adhered to a plurality of tubes.
Alternatively, any number of facesheets and any number of tubes can
be connected to form the sandwich panel of a deck for a modular
structural section. Also, alternatively, various sizes and
configurations of facesheets and cores can be provided to
accommodate various applications. The resulting deck 32 is provided
as a unitary structural component which can be used by itself or as
a component of a modular structural section 30 for thereby
constructing a support structure including a bridge or other
structure therefrom. The deck 32 can be utilized in other
structural applications as described herein.
[0093] As shown in FIGS. 1 and 7, the three sandwich panels 34,
34', 34" are joined at adjacent side edges 33, 33', 33" to form a
planar deck surface 29. The deck 32 is positioned generally above
and coextensively with upper surfaces 57, 58 of the flanges 51, 52
of the beams 50 (FIGS. 1 and 5).
[0094] Each sandwich panel 34 contains a C-channel 39 at each end
44 for joining adjacent sandwich panels 34, 34' in forming the deck
32. As shown in FIG. 7, an internal shear key lock 67 is inserted
into adjacent C-channels 39, 39' to join adjacent sandwich panels
34, 34'. The shear key lock 67 is preferably formed of a bulk
polymer material including, but not limited to, or polymer concrete
mix. Such a shear key lock 67 formed of a polymer is preferred due
to its chemical and corrosive resistant properties. Alternatively,
the shear key lock 67 can be formed o-f various other materials
such as wood, concrete, or metal.
[0095] The shear key lock 67 is bonded with the sandwich panels 34,
34' by an adhesive such as room temperature cure epoxy adhesive or
other bonding means. Alternatively, the shear key lock 67 can be
fastened with fasteners including bolts and screws, and the
like.
[0096] Other methods of joining adjacent sandwich panels to form a
deck could be utilized including, but not limited to, plane joints
with external reinforcement plates on the upper and lower surface
of the sandwich panels, recessed splice joints with reinforcing
plates, externally trapped joints with sandwich panels joined in a
dual connector, match fitting joints, and lap splice joints. These
joints and joining methods are known to one of ordinary skill in
the art and, therefore, are not discussed in detail herein.
[0097] The Beam
[0098] Referring back to FIGS. 1 and 2, the modular structural
section 30 also includes three beams 50, 50', 50'. Any number of
beams, alternatively, can be utilized to construct a modular
structural section 30 of the bridge 20 depending on desired width
span on load requirements. Each of the beams 50, 50', 50" in the
bridge 20 is generally identical in length, width and depth.
However, beams of different lengths and or widths can be utilized
in the modular structural section 30 of the bridge of the present
invention. Alternative embodiments of the beam 50 can be seen in
related, commonly assigned Modular Composite Support Structure
applications referenced previously.
[0099] As shown in FIG. 5, each of the beams 50 comprise lateral
flanges 51, 52 which are positioned on and supported by one of the
two support members 22. Each of the beams 50 has a medial web 53
between and extending below the flanges 51, 52. The medial web 53
includes a inclined sidewall 54 angled generally diagonally with
relation to the lower face sheet 40 (FIGS. 4-6). The flanges 51, 52
and the medial web 53 extend longitudinally along the length of the
beams 50. The configuration of the flanges and the medial web can
take a variety of configurations in alternative embodiments.
[0100] The flanges 51, 52 of the beams 50 are spaced apart, and
each has a generally planar upper surface 57, 58. The upper
surfaces 57, 58 contact the lower facesheets 40 to provide support
thereto. The upper surfaces 57, 58 of each flange 51, 52 also
provide a surface for bonding or bolting the beam 50 to the
sandwich panel 34. The flanges 51, 52 are generally positioned
parallel to the lower surface 42 of the lower facesheet 40 (FIG.
7).
[0101] The inclined side walls 54 of the beams 50 extend at an
angle from the flanges 51, 52. Preferably, this angle is between
about 20.degree. to 35.degree. (preferably about 28.degree.) from
the vertical perpendicular to the planar upper surfaces 57, 58 of a
respective adjacent flange 51, 52. The beams 50 are designed for
simple fabrication and handling.
[0102] The medial web 53 also has a flat floor 68 between the
inclined side walls 54. The floor 68 extends throughout the length
of the beam 50. The floor 68 defines a bottom trough 59 of the flat
U-shaped beam 50 (FIGS. 4-5). The flat floor 68 allows the beam 50
to be supported on an support member 22 having a flat portion 25.
In an alternative embodiment, a bridge can be constructed by
placing the beams 50 on a flat concrete slab supported by the flat
floor portions as explained herein. Column supports of various
configurations can be added in other alternative embodiments to
support the flanges 51, 52.
[0103] The fibers in the floor 68 are preferably substantially
oriented unidirectionally in the longitudinal direction of the beam
50. Such unidirectional fiber orientation provides this beam 50
with sufficient bending stiffness for shorter spans to meet design
requirements, particularly along its longitudinal extent.
[0104] The fibers in the inclined side walls 54 of the web 53 are
oriented in the optimal manner to satisfy design criteria
preferably in a substantially quasi-isotropic orientation. A
significant number of .+-.45.degree. plies are necessary to carry
the transverse shear loads.
[0105] The inclined side walls 54 and the flat floor 68 provide
dimensional stability to the shape of the beam 50 during forming.
The flanges 51, 52 and medial web 53 form a U-shaped open
cross-section having a flat bottom of the beam 50. The beam 50 is
designed to carry multi-direction loads. The inclined side walls 54
transfer load between the deck (compression) and the floor
(tension) and distribute the reaction load to the support members.
As the beam 50 constitutes an open member, the resulting beam 50
provides torsional flexibility during shipping and assembly.
However, when the beam 50 is connected with the deck 32, the
combination thereof forms a closed section which is extremely
strong and stiff.
[0106] As seen in FIG. 4, the flanges 51, 52 of the beams 50 each
also have respective lower surfaces 71, 72. The lower surfaces 71,
72 each provide a surface for positioning the beam 50 on the
support members 22. In constructing the bridge 20, the beams 50 are
positioned on the support members 22 to provide a simply supported
bridge (FIGS. 4 and 5).
[0107] FIG. 6 illustrates an internal diaphragm 84 inserted in the
open trough 25 at each end 55, 56 of the beam 50. The diaphragm 84
is preferably formed of a polymer matrix composite material as
described herein and shown in FIG. 6. Alternatively the diaphragm
84 can be provided of a variety of structural materials including
steel, wood and concrete. The diaphragm 84 increases the torsional
stability of the beam 50 for handling and maintains wall stability
during installation.
[0108] FIGS. 17-19 illustrate alternative diaphragms. FIG. 17
illustrates a plurality of internal diaphragms 170 each having a
periphery shaped to matably contact the contoured shape of the
internal trough 25 of the beams 50 when inserted therein in the
modular structural section 30. A plurality of external diaphragms
172 is also provided. Each external diaphragm 172 has a periphery
shaped to matably contact the exterior surface 85 of adjacent beams
50, 50'. The diaphragm 170 is inserted into the interior of the
beam. The diaphragms 172 are each inserted in the cavity formed
between the exterior surfaces 85, 85' of the beams 50, 50'.
[0109] The diaphragms 170, 172 are preferably formed of a polymer
matrix composite material. Alternatively the diaphragm 170, 172 can
be provided of a variety of structural materials including steel,
wood and concrete. The diaphragms 170, 172 increase the torsional
stability of the beams 50, 50' for handling and maintains wall
stability during installation.
[0110] FIGS. 18 and 19 illustrate external face diaphragms 181 and
191 respectively. Diaphragm 181 is includes a generally rectangular
periphery having an upper and lower edge 182, 183 and vertical
edges 184, 185 generally sized and configured to correspond to the
width and height profile of the modular structural section 30 (FIG.
18). A face 186 of the diaphragm 181 is connected to the end of
modular structural section 30. The vertical edges 184, 185 extend
beyond the inclined side walls 54 of the beams 50, 50" a distance
generally equal to the width of the modular structural section 30
defined by the edges 90, 91 of the modular structural section
30.
[0111] Alternatively, the diaphragm 191 includes a periphery having
an upper and lower edge 192, 193 and vertical edges 194, 195
generally sized and configured to correspond to the width and
height profile of the modular structural section 30 (FIG. 19). The
vertical edges 194, 195 are contoured to correspond to the shape of
the flange 51 and inclined side wall 54 of the outermost beams 50,
50". The diaphragm 191 is connected with the end of the modular
structural section 30.
[0112] The diaphragms 181, 191 are preferably formed of a polymer
matrix composite material. Alternatively the diaphragms 181, 191
can be provided of a variety of structural materials including
steel, wood and concrete. The diaphragms 181, 191 increase the
torsional stability of the beams 50, 50' for handling and maintains
wall stability during installation.
[0113] The diaphragms 170, 172, 181 and 191 are each preferably
connected with the modular structural section 30 by bonding means
such as an adhesive. Alternatively, the diaphragms 170, 172, 181
and 191 can be connected with the modular structural section 30 by
mechanical fastening means, including but not limited to bolts,
screws, or clamps or a combination of mechanical fastening means
and bonding means.
[0114] Returning to the bridge 20 of FIGS. 1-5, and 7, the
U-shaped, flat bottom beams 50 are supported at opposite ends 55,
56 by the support members 22. The U-shaped beams 50 have sufficient
strength, rigidity and torsional stiffness that they are provided
unsupported in the center portion 69 between the ends 55, 56
supported by the support members 22. Alternatively, the beams can
be supported at a variety of interior locations if desired or
depending on the requirements of the span length.
[0115] The beams 50, 50', 50" are also positioned horizontally
adjacent one another on the support members 22. The flanges 51, 52
of each beam 50 each have an outer edge 74. As illustrated in FIG.
5, adjacent outer edges 74, 74' of adjacent beams 50, 50'
preferably form a butt joint 76. As shown in FIG. 5, the flanges
51', 52 of adjacent beams 50, 50' are preferably butt joined such
that the flanges do not extend over or overlap each other with the
medial web 53 of adjacent support webs 53, 53'. Alternatively,
other joints can be provided including joints where the flanges
overlap adjacent flanges without overlapping the medial portions of
the beam.
[0116] Alternative shapes and configurations of the beam 50 can be
provided. Alternative embodiments of the beam 50 can be seen in the
related, commonly assigned Modular Composite Support Structure
applications, previously referenced.
[0117] Each beam 50 in the bridge 20 is hand laid using heavy knit
weight knitted fiberglass fabric. The beam 50 can be formed on a
mold which has a shape corresponding to the contour of the beam 50.
Hand layup methods are well-known to one of ordinary skill in the
art and the details therefore need not be discussed herein.
Alternatively, each beam 50 can be fabricated by automated layup
methods.
[0118] The fabric used in the inclined side walls 54, 58 is a
four-ply quasi-isotropic fabric and polyester resin matrix. The
beam 50 can be fabricated to a predetermined thickness using hand
layup or other method. An additional layer of a predetermined
thickness of unidirectional reinforcement fiberglass is preferably
added to the floor of the beams 50 interspersed between
quasi-isotropic fabrics to further increase their bending
stiffness. The total thickness of the beams 50 can vary across a
range of thicknesses. The thickness of the beam is preferably
between about 0.5 inches and 3 inches. The inclined side walls 54
and flat floor 68 provide dimensional stability to the shape of the
beam 50 during forming.
[0119] The beams 50 of the bridge 20 therefore provide an
improvement over prior concrete and steel beams, which are
extremely rigid and can permanently deform or crack if subjected to
torsional stress or loads during shipping.
[0120] As explained with respect to the core 45 and the upper and
lower facesheets 35, 40, the beams 50 can alternatively be
fabricated by other methods such as pultrusion, resin transfer
molding (RTM), vacuum curing and filament winding and other methods
known to one of skill in the art of composite fabrication, the
details of which are thereby not discussed herein.
[0121] Being formed of polymer matrix composite materials, each of
the beams 50 shown in FIGS. 1-5, and 7 weighs under 3600 pounds for
a 30 foot span design. Beams 50 can, alternatively, be provided
with appropriate weights corresponding to the applicable span,
width and space.
[0122] In constructing the bridge 20 of the embodiment of FIG. 1,
the lateral flanges 51, 52 of the beams 50 are positioned on
adjacent peak portions 23 of the support members 22. The medial web
53, including the inclined side walls 54 and the flat floor 68, are
positioned and supported in the trough portions 25 of the beams 50.
The contoured shaped of the support members 22 which corresponds to
and matably joins with the contoured shape of the beams 50 provides
stability to the components under load, prevents lateral shifting
and facilitates load transfer from the deck through the beams and
support members. The beams 50 are also preferably provided with
longitudinal ends 55, 56 configured to overlappingly join and
thereby secure longitudinally adjacent beams 50, 50'. Therefore,
bridges and support structures of various spans, including spans
longer than the beams 50, can be constructed by joining beams
end-to-end in this fashion. If, alternatively, overlap joints are
utilized, the overlap would be fastened with an adhesive as by
mechanical means. The joints could also be formed with an inherent
interlock in the lap joints.
[0123] As shown in FIGS. 1, 2 and 5, the deck 32 is positioned
above such that it generally coextensively overlies the upper
surfaces 58, 57' of the adjacent flanges 51, 51'. The deck 32 is
also positioned generally parallel with the upper surfaces 57, 57',
58, 58' of the flanges 51, 51', 52, 52' thereby providing a surface
for bonding or bolting the beams to the deck.
[0124] The deck 32 is connected with the beams 50 by inserting
bolts 80 through holes 66 through the lower facesheet 40 and
through holes 78 through the flanges 51, 52 (FIGS. 5-7). The bolts
80 are then fastened with nuts 81 or other fastening means. The
bolts 80 preferably are inserted in holes 78 which extend along the
span of the flanges 51, 52 at intervals of approximately two feet.
At the ends 55, 56 of the beams 50 the spacing of the bolts 80 is
preferably reduced to about one foot. A row of bolts 80 is
preferably inserted through each flange 51, 51', 52, 52' of
adjacent beams 50, 50'.
[0125] To position and access the bolts 80 for securing, holes 79
are formed through the upper facesheet 35 and upper surface 47 of
the tubes 46. These holes 79 have a predetermined diameter
sufficient to allow for insertion of the bolts into the hollow
center of the tubes 46. These holes 79 are also aligned with holes
66, 78 in the lower facesheet 40 and the flanges 51, 52.
[0126] In addition to bolting, the flanges 51, 52 and the deck 32
are also preferably bonded together using an adhesive such as
concresive paste or like adhesives. Thus, a combination adhesive
and mechanical bond is preferably formed between the beams 50, 50',
50" and the deck 32.
[0127] Alternatively, other connecting means can be provided for
connecting the deck to the beams including other mechanical
fasteners such as high strength structural bolts and the like. The
deck and beams can alternatively be connected with only bolts or
adhesives or by other fastening.
[0128] Also, as illustrated in FIG. 1, the bridge 20 preferably is
provided with a wear surface 21 added to the upper surface 75 of
the deck 32. The wear surface 21 is formed of polymer concrete or
low temperature asphalt. Alternatively, the wear surface can be
formed of a variety of materials including concrete, polymers,
fiber reinforced polymers, wood, steel or a combination thereof,
depending on the application.
[0129] In order to construct the bridge 20 referenced in FIG. 1,
support members 22 including peaks 23 are each provided and
positioned at a predetermined position and distance depending on
the span. Adjacent peaks 23 are laterally positioned a
predetermined distance apart corresponding to the distance of
separation between the flanges 51, 52 of the beams 50, 50', 50".
The support members 22 are also positioned longitudinally a
predetermined distance apart equal approximately to the length of
the separation of the ends 55, 56 of the beams 50, 50', 5 on which
are to be supported.
[0130] As shown in FIGS. 4 and 5, the beams 50 are then positioned
on the support members 22. The lateral flanges 51, 52 of each beam
50 are positioned on and supported by adjacent vertical columns 31
of the support members 22 as described. Further, each longitudinal
end 55, 56 of the beams 50, 50', 50" is positioned on and supported
by a support member 22. Likewise, the medial web 53 of each beam 50
is then positioned in adjacent trough portions 25. Adjacent flanges
52 and 51' of adjacent beams 50 and 50' are positioned adjacent one
another on a single peak 23.
[0131] Adjacent sandwich panels 34, 34' are then positioned and
lowered onto the beams 50, 50', 50". The sandwich panels 34 are
also aligned next to adjacent sandwich panels 34' and connected
with the shear key lock 67 or other connecting means as described
above. The deck 32 is preferably aligned with the beams 50, 50', 5
on such that the longitudinal ends of the deck 32 are positionally
aligned with the ends defining the length of the beams 50.
Likewise, the edges 86, 87 defining the width of the deck 32 are
preferably aligned above the outside edges 88, 89 of the beams 50
defining the width of the three beams 50, 50', 50".
[0132] The deck 32 is then fastened to the beams 50 as described
above using adhesives, fasteners, including, but not limited to
bolts, screws or the like, other connecting means or some
combination thereof. After aligning and connecting each of the
sandwich panels 34, 34', 34", the deck 32, as shown in FIG. 1, is
then completed. The bridge 20 includes a concrete guard rail 82
along each side of the length of the span.
[0133] Alternatively, guard rails, walkways, and other accessory
components can be added to the bridge. Such accessory components
can be formed of the polymer matrix composite materials as
described herein or other materials including steel, wood, concrete
or other composite materials.
[0134] An alternative embodiment of the support structure in the
form of bridge 100 including the modular structural section 30
according to the present invention is shown (FIGS. 9-10). The
bridge 100 includes the modular structural section 30 described
herein and illustrated in FIG. 2 and support members 101. Like
reference numerals with respect to the modular structural section
30 of FIGS. 1-2 are included in FIGS. 9-10.
[0135] The support members 101 are precast concrete abutments
having a generally flat upper surface 102 (FIGS. 9-10). A load pad
105 is positioned with its lower surface 106 in a predetermined
location on the upper surface 102 of the support member 101. Each
of the support beams 50, 50', 50" is positioned with the lower
surface 70 of the flat floor 68 generally above the upper surface
108 of the load pad 105 (FIG. 10). The load pads 105 absorb load to
protect the support member 101 from scratching, cracking or other
failure caused by the load of the modular structural section
30.
[0136] The modular structural section 30 is positioned with its end
87 generally above the middle portion of the upper surface 102 of
the support member 101 in the direction of the span of the bridge
100 (FIG. 9). An adjacent modular structural section 30 can be
placed on the flat support member 101 in alternative embodiments.
Further alternatively, the modular structural section 30 can be
positioned in other positions on the upper surface 102 of the
support member 101 such as with the end 87 generally above the edge
103 of the support member 101. The support member 101, also
alternatively, can be positioned at any location along the span of
the modular structural section 30 as described with respect to the
embodiment of the bridge 20 in FIGS. 1-2.
[0137] The flanges 51, 52 of the beams 50, 50', 50" are connected
with the deck 32 as-described herein. The flanges 51, 52 are not in
contact with the support member 101 in this embodiment (FIGS.
9-10).
[0138] The support member 101, in alternative embodiments, can be
formed of other materials including, but not limited to polymer
matrix composite and other composite materials, wood, steel and
other materials.
[0139] FIGS. 13-14 illustrate a further alternative embodiment of
the structural support according to the present invention in the
form of bridge 120. The bridge 120 includes a modular structural
section 130 and support members 101. The support members 101 are
those of bridge 100 illustrated in FIGS. 9-10, the description of
which is hereby incorporated by reference. The modular section 130
includes the deck 32 as described herein with respect FIGS. 1-2 and
beams 150, 150', 150" having a U-shape including a curved floor
168. Like reference numerals with respect to the deck 32 of FIGS.
1-2 are included in FIGS. 13-14. The beam 150 is described in
detail in the "Modular Composite Support Structure" application
previously referenced and incorporated by reference herein.
[0140] A load pad 105 is positioned with its lower surface 106 in a
predetermined location on the upper surface 107 of the support
member 101 (FIG. 14). Each of the support beams 150, 150', 150" is
positioned with the lower surface 151 of the curved floor 168
generally above the upper surface 108 of the load pad 105 (FIG.
14).
[0141] The modular structural section 130 is positioned with its
end 87 generally above the middle portion of the upper surface 102
of the support member 101 in the direction of the span of the
bridge 120 (FIG. 14). Alternatively, the modular structural section
30 can be positioned in the various locations described with
reference to the embodiment of FIGS. 9-10.
[0142] Like the embodiment of FIGS. 9-10, the flanges 151, 152 of
the beams 150, 150', 150" are connected with the deck 32 as
described with respect to the modular structural section 30 herein.
The flanges 151, 152 are not in contact with the support member 101
in this embodiment (FIG. 13).
[0143] Alternatively, depending of the curvature of the radius of
the curved floor 168, a stabilizing member or other stabilizing
means for stabilizing the beam on the support member 101 can be
positioned adjacent the beam 50 and the support member 101 in
alternative embodiments. Suitable stabilizing means include, but
are not limited to, members which would stabilize the curved floor
168 by wedging, cradling, or receiving the beam 150. Further
alternatively, the support member 101 can be formed having a
contoured shape to receive the beam 150 similar to the contoured
support member 22 illustrated and described with reference to FIGS.
1 and 2.
[0144] An additional embodiment of a support structure in the form
of bridge 110 is provided having the modular deck 32 and beams 50,
50', 50" of bridge 20 as described herein with an L-shape support
member 111 (FIGS. 11-12). The L-shape support member 111 is a
precast concrete abutment. The support member has a lower ledge 112
disposed generally horizontally and a vertical wall 114 generally
perpendicular to the lower ledge 112. The lower ledge 112 and the
vertical wall 114 form a v-shape configured to receive the modular
structural section 30.
[0145] Each of the load pads 105, as previously described, is
positioned with its lower surface 106 in a predetermined location
on the lower ledge 112 of the support member 111 (FIG. 12). Each of
the support beams 50, 50', 50" is positioned with the lower surface
70 of the flat floor 68 generally above the upper surface 108 of
the load pad 105 (FIG. 12).
[0146] The modular structural section 30 is positioned with its end
87 generally contacting the vertical wall 114. Thus, the modular
structural section 30 is positioned within the v-shape of the
support member 111 providing stability to the modular section 30
(FIGS. 11-12).
[0147] Depending of the span of the bridge or other structure a
support member 111 can be utilized at each end of the modular
structural section 30 or span of the bridge. The upper ledge 115 is
preferably below the level of the wear surface 21 of the deck
32.
[0148] In bridge 110, The flanges 51, 52 of the beams 50, 50', 50"
are connected with the deck 32 as described herein. The flanges 51,
52 are not in contact with the support member 111 in this
embodiment.
[0149] The support member 111, in alternative embodiments, can be
formed of other materials including, but not limited to polymer
matrix composite and other composite materials, wood, steel, and
other materials.
[0150] In a still further embodiment, a bridge 140 is provided
(FIGS. 15-16). The bridge 140 has the modular structural section
130 described with respect to FIGS. 13-14 and the support member
111 described and illustrated in FIGS. 11-12. Each of the load pads
105, as previously described, is positioned with its lower surface
106 in a predetermined location on the lower ledge 112 of the
support member 111 (FIG. 16). Each of the support beams 150, 150',
150" is positioned with the curved floor 168 generally above the
upper surface 108 of the load pad 105 (FIG. 16).
[0151] The modular structural section 130 is positioned with its
end 187 generally contacting the vertical wall 114. Thus, the
modular structural section 130 is positioned within the v-shape of
the support member 111 providing stability to the modular section
130 (FIGS. 11-12).
[0152] Depending of the span of the bridge or other structure a
support member 111 can utilized at each end of the modular
structural section 130 or span of the bridge. The upper ledge 115
is preferably below the level of the wear surface 121 of the deck
132.
[0153] In bridge 140, The flanges 151, 152 of the beams 50, 50',
50" are connected with the deck 132 as described herein. The
flanges 151, 152 are not in contact with the support member 111 in
this embodiment.
[0154] The support member 111, in alternative embodiments, can be
formed of other materials including, but not limited to polymer
matrix composite and other composite materials, wood, steel, and
other materials.
[0155] Returning to the embodiment illustrated in FIGS. 1-5 and 7,
bridge 20 can also be provided as a kit comprising at least one
modular structural section 30 having a deck 32 including at least
one sandwich panel 34 and at least one beam 50 and, preferably,
connecting means for connecting the deck 32 and the beams 50. Such
a kit can be shipped to the construction site. Alternatively, a kit
for constructing a support structure can be provided comprising at
least one modular structural section having at least one sandwich
panel configured and formed of a material suitable for constructing
a support structure without necessitating a beam.
[0156] The use of the bridge 20 in remote terrains (e.g., timber,
mining, park or military uses) is facilitated by such kits which
can have components including modular structural sections 30 having
a deck 32 including sandwich panels 34 and at least one beam 50,
which each can be sized to have dimensions less than a variety of
dimensional limitations of various transportation modes including
trucks, rail, ships and aircraft. For example, the beam 50 and
sandwich panel 34 can be sized with dimensions to fit within a
standard shipping container having dimensions of 8 feet by 8 feet
by 20 feet. Further, the components can alternatively be sized to
fit into trailers of highway trucks which have a standard size of
up to a 12 foot width. Moreover, such a kit can be provided having
dimensions which would fit in cargo aircraft or in boat hulls or
other transportation means. Further, the components, including, but
not limited to, the U-shaped beam 50 and sandwich panel 34, can be
provided as described which are stackable within or on top of
another to utilize and maximize shipping and storage space. The
light weight of the components of the modular structural section 30
also facilitates the ease and cost of such transportation.
[0157] The lightweight modular components of the modular structural
section 30 also facilitate pre-assembly and final positioning with
light load equipment in constructing the bridge. As described, the
bridge 20 of the present invention can be easily constructed. For
example, for a 30 foot span bridge 20, a three man crew utilizing a
front end loader or forklift and a small crane can construct the
bridge in less than five to ten working days. As compared to
bridges constructed by conventional steel and concrete materials,
the highway bridge 20 is approximately twenty percent of the weight
of a similar sized bridge constructed from conventional materials.
Structurally the bridge 20 also provides a traffic bearing highway
bridge designed to reduce the failure risk by providing redundant
load paths between the deck and the supports. Further, the specific
stiffness and strength far exceed bridges constructed of
conventional materials, in the embodiment shown in FIGS. 1-7 being
approximately as much as 60 percent greater than conventional
bridges.
[0158] The bridge 20 of the present invention can also be
constructed to replace an existing bridge, and thereby, utilize the
existing support members of the existing bridge. Prior to
performing the steps of constructing a bridge described above, the
existing bridge span of an existing bridge must be removed, while
retaining the existing support members. The at least one beam 50
can then be placed on the existing support members and the bridge
20 constructed as described. Alternatively, additional support
members can be positioned or cast on the existing supports and the
bridge then constructed according to the method described herein.
Alternative methods of constructing a bridge according to the
present invention can be seen in the related Modular Composite
Support Structure applications previously referenced.
[0159] Further, the modular structural section 30 or its components
including the beam 50 or deck 32 can be used to also repair a
bridge. An existing bridge section can be removed and replaced by a
modular structural section 30 or component of the beam 50 or deck
32 as described. Further, a bridge 20, once constructed, can be
easily repaired by removing and replacing a modular structural
section 30, sandwich panel 34 or beam 50. Such repair can be made
quickly without extensive heavy machinery or labor.
[0160] The bridge 20 of the present invention also can be provided
with a variety of widths and spans, depending on the number, width
and length of the modular structural sections 30. A bridge span is
defined by the length of the bridge extended across the opening or
gap over which the bridge is laid. Thus, the configuration of the
modular structural section 30, with its sandwich panel 34 and beam
50, provides flexibility in design and construction of bridges and
other support structures. For example, in alternative embodiments,
a single sandwich panel may be-supported by a single or multiple
beams in both the span and width directions. Likewise, a single
beam may support a portion or an entirety of one of more sandwich
panels. Also, the length and width of the separate sandwich panels
34 need not correspond to the length and width of the beams 50 in a
modular structural section 30 of the bridge 20 constructed
therefrom. Alternatively, a variety of number of sandwich panels
can be utilized to provide the desired span and width of the
bridge.
[0161] Adjacent sandwich panels 34, 34' can be joined
longitudinally in the direction of the span of the bridge 20, as
shown in FIG. 1, and/or laterally in the direction of the width of
the bridge. As such, a bridge also can be provided with a variety
of lanes of travel.
[0162] As the beams 50 can also be supported at a variety of
locations along their length, the bridge span is not limited by the
length of the beams. The span of the bridge 20 shown in FIG. 1
coincides with the length of the beams 50. However, beams, in other
embodiments, are provided which can be joined with adjacent beams
longitudinally to form a bridge having a span comprising the sum of
the lengths of the beams.
[0163] The bridge 20 of the present invention is a simply supported
bridge which is designed to meet AASHTO specifications as
previously incorporated by reference herein. As such, the bridge
meets at least specific AASHTO standards and other standards
including the following criteria. The bridge supports a load of one
AASHTO HS20-44 Truck (72,000 lb) in the center of each of four
lanes. The bridge also is designed such that the maximum deflection
(in inches) under a live load is less than the span divided by 800.
The allowable deflection for a 60 foot span would be less than 0.9
inches. Further, the bridge meets California standards that for
simple spans less than 145 feet, the HS load as defined by AASHTO
standards produce higher moment and deflection than lane or
alternative loadings.
[0164] The bridge 20 is also designed to meet certain strength
criteria. The bridge 20 has a positive margin of safety using a
"first-ply" as the failure criteria and a safety factor of 4.0,
which is commonly used in bridge construction to account for
neglected loading, load multipliers, and material strength
reduction factors. A positive margin of safety is understood to one
of ordinary skill in the art, and the details are therefore not
discussed herein.
[0165] Further, the bridge is designed and configured such that its
buckling eigenvalue (E.V.) .alpha./FS>1, wherein (E.V.) is the
buckling eigenvalue, a is the knockdown factor of said modular
structural section, and FS is the factor of safety. Such buckling
considerations are also known to one of ordinary skill in the art
and therefore not discussed in detail herein.
[0166] In the bridge shown in FIGS. 1-7, shear loads must be
transmitted between the web 53 and flanges 51, 52 of the beams 50,
50', 50" and the sandwich panels 34, 34' of the deck 32. This load
transfer is achieved in this embodiment of the bridge 20 by
bolting. The maximum expected shear load is approximately 4,000
lbs., while the capacity exceeds 17,000 lbs. The deformation and
fracture behavior appears ductile leading to load redistribution to
surrounding bolts rather than catastrophic failure. Being made of a
polymer matrix composite material which is environmentally
resistant to corrosion and chemical attack, the sandwich panels 34,
as well as the beams 50 can also be stored outdoors, including on
site of the bridge 20 construction, without deterioration or
environmental harm. The sandwich panels 34 and the beams 50 are
preferably gel coated or painted with an outer layer containing a
UV inhibitor. Further, the sandwich panels 34 and the beams 50 can
be utilized in applications in corrosive or chemically destructive
environments such as in marine applications, chemical plants or
areas with concentrations of environmental agents.
[0167] The invention will now be described in greater detail in the
following non-limiting example.
EXAMPLE 1
[0168] A trapezoidal tube deck for a 30 ft bridge of the
configuration generally as described with respect to FIGS. 1-7 was
constructed. The deck included sandwich panels which are 7.5 feet
in length in the direction of the span of the bridge and 15 feet in
width in the direction transverse to the span. The bridge was
simply supported at the ends of the 30 foot span. The deck was
designed to have a maximum depth limit of 9 inches with a 0.75 inch
polymer concrete wear surface bonded to the top of the deck,
leaving 8.25 inches for the sandwich panel.
[0169] The sandwich panels were constructed comprising a 6.5 inch
deep E-glass/Vinylester trapezoidal tube with facesheets of a
hybrid of E-glass and carbon fibers. The trapezoidal tubes were
made by hand lay-up. The tubes had a 0.25 inch thick trapezoidal
section of 80 percent .+-.45.degree. fabric with 20 percent
0.degree. tow fibers. In addition, a 0.25 inch floor of 100 percent
0.degree. fibers was applied to the top and bottom surfaces. The
hand lay-up tubes had a fiber volume of about 40 percent.
[0170] The facesheets contained a hybrid of E-glass and graphite. A
0.136 inch layer of quasi-isotropic E-glass was placed on the outer
surface of the facesheets. The facesheet thickness was 0.5 inches.
The layup had 42 percent graphite and 58 percent glass to provide a
satisfactory stiffness.
[0171] A wheel load was applied in a deck section in using a
hydraulic load frame according to AASHTO 20-44 standards. An entire
axle load of 32 kips must be carried by a side 7.5 foot long panel
without any contribution from an adjacent panel. Each wheel load is
16 Kips. The wheel load is spread over an area of approximately 16
inches by 20 inches which is the size of a double truck tire
footprint.
[0172] An ABACUS model was used to generate plots of the stresses
in all directions in the critical region.
[0173] The bridge meets the margin of safety defined as 1 MS =
Allowable Stress Applied Stress - 1
[0174] with a positive margin of safety indicating no failure at
the design load.
[0175] The critical condition for this deck is interlaminar shear.
The failure is interlaminar shear in the corner between the
diagonal member and the top surface. This failure will occur at
2.28 times the 32 Kips axle load or about 73 Kips.
[0176] The deck was designed to maintain a bending stiffness no
less than 80 Kips/inch which is the stiffness of an equivalent
concrete slab. The deck also was designed to withstand an ultimate
design load of 90 Kips which is approximately two (2) times the
AASHTO traffic wheel load specifications.
EXAMPLE 2
[0177] A second trapezoidal tube deck for the 30 ft. bridge
described in Example 1 was also constructed. The deck was of a
similar configuration as the deck described in Example 1, except
the facesheets were all E-glass fibers instead of the hybrid deck
of Example 1. The facesheets were 0.85 inch thick with a layup of
0/45/900/-45.
[0178] The upper and lower facesheets were each fabricated with
alternating layers of quasi-isotropic and unidirectional knitted
fabric. The upper facesheet included a construction of multiple
plies. The upper facesheet included a lower ply of 52 oz
quasi-isotropic fabric, a middle layer of 3 plies of 48 oz
unidirectional fabric and an upper layer of 12 plies of 52 oz
quasi-isotropic fabric.
[0179] The lower facesheet likewise included a construction of
multiple plies. The lower facesheet included an upper ply of 52 oz.
quasi-isotropic fabric, a middle layer of 3 plies of 48 oz.
unidirectional fabric and a lower layer of 12 plies of 52 oz.
quasi-isotropic fabric. The outer quasi-isotropic plies provide
durability while the unidirectional plus odd stiffness and
strength.
[0180] Under the same load conditions as Example 1, the critical
condition for the E-glass deck is also interlaminar shear. The
critical limitation is this deck is also interlaminar shear. In
this deck the failure occurs first in the top section of the
pultrusion at the interface between the top of the pultrusion and
the diagonal member. The failure will occur at 2.51 times the 32
Kips load or about 80 Kips.
[0181] The deck was also designed to maintain a bending stiffness
no less than 80 Kips/in which is the stiffness of an equivalent
concrete slab. The deck also was designed to withstand an ultimate
design load of 90 Kips which is approximately two (2) times the
AASHTO traffic wheel load specifications.
[0182] The deck exhibited consistent-stiffness of 85 Kips/in under
cyclic loading up to 180 kips. The deck also withstood 218 kips
which is the maximum limit of the load fixture before showing a
drop in stiffness to 79 kips/inch.
[0183] In the drawings and specification, there has been set forth
a preferred embodiment of the invention and, although specific
terms are employed, the terms are used in a generic and descriptive
sense only and not for purposes of limitation, the scope of the
invention being set forth in the following claims.
* * * * *