U.S. patent application number 12/555207 was filed with the patent office on 2010-06-17 for air beam with stiffening members and air beam structure.
Invention is credited to Stanislaw Lukasiewicz, Harold Warner.
Application Number | 20100146868 12/555207 |
Document ID | / |
Family ID | 41808979 |
Filed Date | 2010-06-17 |
United States Patent
Application |
20100146868 |
Kind Code |
A1 |
Lukasiewicz; Stanislaw ; et
al. |
June 17, 2010 |
Air Beam with Stiffening Members and Air Beam Structure
Abstract
An air beam structural member having an elongate pneumatic
tubular column, a plurality of stiffening members, and means for
connecting the tubular column and the stiffening members. An
inflatable shelter includes pneumatic tubular columns (arches)
covered on both sides by flexible membranes. The columns are placed
side by side to create a wall and enclosure of the space. The
pneumatic columns are pressurized and keep their shape by means of
a set of cables reinforcing them in the plane of the columns. The
structure may be supported by an external support structure.
Inventors: |
Lukasiewicz; Stanislaw;
(Calgary, CA) ; Warner; Harold; (Calgary,
CA) |
Correspondence
Address: |
DIEDERIKS & WHITELAW, PLC
12471 Dillingham Square, #301
Woodbridge
VA
22192
US
|
Family ID: |
41808979 |
Appl. No.: |
12/555207 |
Filed: |
September 8, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61094710 |
Sep 5, 2008 |
|
|
|
Current U.S.
Class: |
52/2.11 ;
52/741.1; 52/745.07 |
Current CPC
Class: |
E04H 15/20 20130101;
E04H 15/18 20130101; E04H 2015/201 20130101 |
Class at
Publication: |
52/2.11 ;
52/745.07; 52/741.1 |
International
Class: |
E04H 15/20 20060101
E04H015/20; E04B 1/343 20060101 E04B001/343; E04B 1/35 20060101
E04B001/35 |
Claims
1. A structural member comprising: (a) an elongate pneumatic
tubular column; (b) a plurality of stiffening members; and (c)
means for connecting the tubular column and the stiffening
members.
2. The structural member of claim 1, adapted to form an arch having
an inner side and an outer side, the plurality of stiffening
members connected with the tubular column on the inner side.
3. The structural member of claim 2, the stiffening members
comprising a cable extending between two connectors, the connectors
fixed to the tubular column.
4. An air beam structure comprising: (a) a plurality of structural
members having i. a plurality of elongate pneumatic tubular
columns, separated one from another by a gap; ii. a plurality of
stiffening members connected with the elongate pneumatic tubular
columns; and (b) a flexible membrane covering the plurality of
structural members and the gap.
5. The air beam structure of claim 4, further comprising: (a) a
support structure, above the air beam structure, the support
structure adapted to support at least a portion of the
structure.
6. The air beam structure of claim 5, the support structure
comprising at least two support towers, a support member extending
between the at least two support towers.
7. The air beam structure of claim 6, a plurality of support cables
extending between the support member and the structural
members.
8. The air beam structure of claim 5, wherein the support member is
a suspended cable.
9. The air beam structure of 5, wherein the support member is a
suspended structural beam.
10. A method of constructing an air beam structure comprising: (a)
providing an elevated support structure, adapted to support at
least a portion of the air beam structure; (b) providing a
plurality of structural members having: i. a plurality of elongate
pneumatic tubular columns, separated one from another by a gap; ii.
a plurality of stiffening members connected with the elongate
pneumatic tubular columns; (c) supporting each of the plurality of
structural members from the support structure prior to connecting
the stiffening members; and (d) covering the outer side of the
structural members with a flexible membrane covering the plurality
of structural members and the gap.
11. A method of determining the size and placement of a plurality
of stiffening members for a pneumatic tubular column, comprising:
(a) selecting a selected stiffening member from the plurality of
stiffening members, the selected stiffening member having a
stiffness; (b) adding the stiffness to a system general stiffness
matrix if the selected stiffening member is in tension; (c)
subtracting the stiffness from the system general stiffness matrix
if the selected stiffening member is in compression; and (d)
repeating steps (a) to (c) for the plurality of stiffening members
in order to determine the system general system matrix.
12. The method of claim 11, wherein the stiffening member is a
tension member.
13. The method of claim 12, wherein the tension member is a cable.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of priority of U.S.
Provisional Patent Application No. 61/094,710 filed Sep. 5, 2008,
which is incorporated herein by reference in its entirety.
FIELD OF THE INVENTION
[0002] The present invention relates generally to air supported
structures. More particularly, the present invention relates to air
supported structures resistant to high static or dynamic load or
both.
BACKGROUND OF THE INVENTION
[0003] There have historically been a variety of air supported
structures. That is, structures which are internally pressurized.
U.S. Pat. No. 3,159,165 to Cohen et al., for example, teaches a
shelter or enclosure relying on pressurized air for support. As
such structures require a constant air pressure to maintain the
structure, a constant supply of pressurized air and a sealed
entry/exit to reduce air loss.
[0004] Another approach is to form an inflatable structural member,
which are combined and covered to form a structure. These are
commonly referred to as "air beams". This construction does away
with the necessity that the structure be pressurized, but air beams
are inherently susceptible to bending and collapse.
[0005] Conventional inflatable shelters utilize complex shaped
inflatable members that are difficult to manufacture. These
shelters are erected only as small units not larger than about 20 m
in width or diameter. They are created very often in such a way
that once damaged the entire shelter must be replaced. Shelters
employing multiple tubes that are connected one to each at the apex
are difficult to cover by a fly. But the most important drawback of
these shelters is that they can be built only with relatively
smaller dimensions.
[0006] When a larger shelter is built in this way, it wrinkles,
buckles and collapses under snow or high wind loads, even if the
dimensions of the tubes or pressure in the tubes is increased.
[0007] U.S. Pat. No. 5,735,083 to Brown et al. teaches an air beam
made up of a cylindrical braid and lined with a gas-retaining
bladder. Linear bundles extending parallel to the axis of the
cylindrical braid are incorporated within the cylindrical braid to
improve resistance of the air beam to wrinkling or buckling. In a
further implementation, the linear bundles are made up into
external straps and retained by a coating applied to the braided
fibres.
[0008] It is, therefore, desirable to provide an improved
structural member, structure, method of assembly/disassembly, and
design.
SUMMARY OF THE INVENTION
[0009] A large inflatable structure includes pneumatic tubular
columns (arches) covered on both sides by flexible membranes. The
column are placed side by side what creates a wall and enclosure of
the space. The structure includes two side walls equipped with
large doors providing the entrance to the structure. The design of
the structure is oriented to the fact that the dimensions of the
structure could be very large of the order of 100 m width 200 m
long and 50 m high and satisfy the safety conditions against
buckling and burst of the columns. The pneumatic columns are under
the internal pressure of the air and keep their shape by means of
the set of cables reinforcing them in the plane of the tubes. The
tubes are covered with external and internal membrane-fly attached
to the columns. The columns can be also supported by an external
support member connected to support towers on both ends of the
structure. The use of the support member and towers is related to
the dimensions of the structure. Smaller structures require only
reinforcing by side and internal cables. Larger structures benefit
from support member(s) and towers.
[0010] The structure is built in the way that it is easy dismantle
and removable. The columns are easily deflected and erected or
replaceable.
[0011] Due to the fact that the structure consists of a composition
of tubular pneumatic elements, cables and support towers, it
requires special computational tools able to deal with different
types of the elements of the structure. The pneumatic column is a
very flexible member of the system and it is not possible to
predict its buckling conditions using method and software that are
commercially available on the market. Particularly, the application
of cables, which provide the support only when they are in tension
produce great difficulties when attempting to apply the
conventional finite element software and methods. The method of the
calculations used to define buckling strength and stability is
based on the theory utilizing the idea of pneumatic hinges to
determine buckling loads.
[0012] The method of pneumatic hinges was described in the papers
S.A. Lukasiewicz and L. Balas, "Collapse Loads of a Cylindrical and
Toroidal Free Standing Membrane": International Journal of
Mechanics of Structures and Machines, 18,(4) 1990 pp 499-513 and
S.A. Lukasiewicz and L. Balas. "Collapse Modes of Inflatable
Membranes" International Journal of Mechanics of Structures and
Machines, 18,(4) 1990 pp 483-497.
[0013] It is known that if the internal forces and moments in a
pneumatic column reach a certain critical value the column
collapses. Therefore, to determine load carrying capabilities of
the structure it is necessary first to find the forces and moments
in the column, and second, to determine if these forces are in a
safe range. A method of analysis "Space Frame Cable System
Analyzer" (SFCSA), preferably embodied in software using finite
element modeling has been developed and used to predict the values
of the normal forces and bending moments in the pneumatic columns
of the present invention. The method has been developed on the
assumption that the problem is static. Then the idea of pneumatic
hinges was utilized to determine the buckling loads. SFCSA is a
space frame finite element analysis program which integrates curved
pneumatic columns and cables-tension only link elements. The
tension only feature of the cables is implemented by iterations. In
each iteration step, if a cable is in tension, its stiffness is
added to system general stiffness matrix. If the cable is in
compression its stiffness is removed from system general stiffness
matrix, and the calculations are repeated. This procedure is
followed until stiffness of all cables in tension is added to
system general stiffness matrix, and stiffness of all cables not in
tension is removed from the system general stiffness matrix. In
addition, the effect of large finite displacements of the columns
may also be included in each iteration.
[0014] The calculations of the stability of the structure and loads
causing the collapse of the structure have been performed for two
types of load: for snow and wind loads. The dead load due to the
weight of the structure was included in both cases.
[0015] The positions of the attachment of the cables to the
pneumatic columns may be obtained by analysis through the method of
the FSCSA software. Using the FSCSA method it is possible to
optimize the position of the cables.
[0016] It is an object of the present invention to obviate or
mitigate at least one disadvantage of previous apparatus and method
for designing and providing air supported structures.
[0017] In one aspect the present invention provides a structural
member having an elongate pneumatic tubular column, a plurality of
stiffening members, and means for connecting the tubular column and
the stiffening members.
[0018] In one embodiment, the structural member is adapted to form
an arch having an inner side and an outer side, the plurality of
stiffening members connected with the tubular column on the inner
side.
[0019] In one embodiment, the stiffening members include a cable
extending between two connectors, the connectors fixed to the
tubular column.
[0020] In a further aspect the present invention provides an air
beam structure having a plurality of structural members having a
plurality of elongate pneumatic tubular columns, separated one from
another by a gap, a plurality of stiffening members connected with
the elongate pneumatic tubular columns, and a flexible membrane
covering the plurality of structural members and the gap.
[0021] In one embodiment, the air beam structure includes a support
structure, above the air beam structure, the support structure
adapted to support at least a portion of the air beam
structure.
[0022] In one embodiment, the support structure includes at least
two support towers, a support member extending between the at least
two support towers.
[0023] In one embodiment, a plurality of support cables extend
between the support member and the structural members.
[0024] In one embodiment, the support member is a suspended cable.
In one embodiment, the support member is a suspended structural
beam.
[0025] In a further aspect, the present invention provides a method
of constructing an air beam structure including providing an
elevated support structure, adapted to support at least a portion
of the air beam structure, providing a plurality of structural
members having a plurality of elongate pneumatic tubular columns,
separated one from another by a gap, and a plurality of stiffening
members connected with the elongate pneumatic tubular columns,
supporting each of the plurality of structural members from the
support structure prior to connecting the stiffening members, and
covering the outer side of the structural members with a flexible
membrane covering the plurality of structural members and the
gap.
[0026] In a further aspect, the present invention provides a method
of determining the size and placement of a plurality of stiffening
members for a pneumatic tubular column, including selecting a
selected stiffening member from the plurality of stiffening
members, the selected stiffening member having a stiffness, adding
the stiffness to a system general stiffness matrix if the selected
stiffening member is in tension, subtracting the stiffness from the
system general stiffness matrix if the selected stiffening member
is in compression, and repeating the steps for remainder of the
plurality of stiffening members in order to determine the system
general system matrix.
[0027] In one embodiment, the stiffening member is a tension
member. In one embodiment, the tension member is a cable.
[0028] Other aspects and features of the present invention will
become apparent to those ordinarily skilled in the art upon review
of the following description of specific embodiments of the
invention in conjunction with the accompanying figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] Embodiments of the present invention will now be described,
by way of example only, with reference to the attached Figures,
wherein:
[0030] FIG. 1 is a perspective view of a structure of the present
invention in an embodiment having air columns reinforced by
external stiffening members;
[0031] FIG. 2 is a cross-section view of the structure of FIG.
1;
[0032] FIG. 3 is a perspective view of a structure of the present
invention in an embodiment having a longitudinal support member
above and connected with the structure;
[0033] FIG. 4 is a cross-section view of the structure of FIG.
3;
[0034] FIG. 5 is a perspective view of a structure of the present
invention in an embodiment having a plurality of longitudinal
support members above and connected with the structure;
[0035] FIG. 6 is a cross-section view of the structure of FIG.
5;
[0036] FIG. 7 is a cross-section view of a structure of the present
invention in an embodiment having a plurality of longitudinal
support members above and connected with the structure and guy
members;
[0037] FIG. 8 is a cross-section view of a structure of the present
invention in an embodiment having a plurality of longitudinal
support members above and connected with the structure and internal
stiffening members;
[0038] FIG. 9 is a perspective partial cross-section view of a wall
section of the structure of FIG. 1, 3, or 5 showing spacing between
adjacent columns;
[0039] FIG. 10 is a detail cross-section view of a column or
structural member of the present invention, showing the cable and
column connection;
[0040] FIG. 11 is a detail view showing a rigid opening associated
with a structure of the present invention;
[0041] FIG. 12 is a structure of the present invention having a
support tower protruding through the structure;
[0042] FIG. 13 is a structure of the present invention having a
shape selected to include/exclude non-uniform areas/spaces;
[0043] FIG. 14 is a detail of a portion of the support structure of
the structure of FIG. 12;
[0044] FIG. 15 is a detail view of an end portion of the structure
of FIG. 5;
[0045] FIG. 16 is a further view of the structure of FIG. 5;
[0046] FIG. 17 is an embodiment of a connector for use with a
structure of the present invention;
[0047] FIG. 18 is an embodiment of a connector for use with a
structure of the present invention;
[0048] FIG. 19 is a perspective detail view of a portion of the
structure of FIG. 5;
[0049] FIG. 20 is a side view the structure of FIG. 12; and
[0050] FIG. 21 is an end view of the structure of FIG. 5.
DETAILED DESCRIPTION
[0051] Generally, the present invention provides a method and
apparatus for designing and providing an air beam structure.
[0052] Referring to FIGS. 1 and 2, a structure 10 of the present
invention is assembled from a plurality of structural members 20
covered by a flexible membrane 30. The structural member 20
includes an elongate pneumatic tubular column 40 formed into an
arch shaped air beam. A plurality of stiffening members in the form
of cables 50 are connected with the tubular column 40 by connectors
60. As shown, the cables 50 generally traverse the inside of the
tubular column 40 to increase its resistance to bending, buckling,
collapse or a combination of bending, buckling, or collapse from
exterior loads such as wind, snow, sand, ice etc.
[0053] The structure 10 may include one or more end wall doors 25
and/or side wall doors 27.
[0054] The positions of the connectors 60 on the columns 40 are
defined by means of the FSCSA method for each case. A preferred
design of the attachment provides that the forces act on the
columns perpendicularly to the pneumatic columns only.
[0055] The large structure column is not able to carry a snow load.
The snow provides a large vertical load which may cause the
wrinkling or buckling of the column. Eventually the column may
collapse causing the collapse of the whole structure. To improve
the buckling strength of the pneumatic tubular column 40 the
internal cables 50 are installed along the pneumatic tubular column
40. The cables 50 may increase the bending stability of the
pneumatic tubular column 40 by up to 30% or more.
[0056] Referring to FIGS. 3 and 4, the structure 10 of the present
invention may be assembled from a plurality of structural members
20 covered by the flexible membrane 30. A support structure 70 is
fixed above the structure 10 to support at least a portion of the
structure 10. The support structure 70 includes a support member 80
extending between support towers 90. The support member 80 may
comprise a suspended cable 100 supported by a plurality of
suspension support cables 107 from a suspension cable 105 from the
support towers 90 (somewhat like a suspension bridge). A plurality
of support cables 110 extend between the suspended cable 100 and
one or more of the structural members 20. Alternatively, the
support member 80 may be a structural member, such as a beam or
series of beams.
[0057] Referring to FIGS. 5, 6, 11, 16, and 21 the structure 10 of
the present invention is assembled from a plurality of structural
members 20 covered by a flexible membrane 30 (for example a fly
35). The support structure 70 is fixed above the structure 10 to
support at least a portion of the structure 10. The support
structure 70 includes the support members 80 extending between the
support towers 90. The support member 80 may comprise a suspended
cable 100 supported by a plurality of suspension support cables 107
from a suspension cable 105 from the support towers 90 (somewhat
like a suspension bridge). A plurality of support cables 110 extend
between the suspended cable 100 and one or more of the structural
members 20. Alternatively, the support member 80 may be a
structural member, such as a beam or series of beams.
[0058] Referring to FIG. 7, a plurality of guy members in the form
of guy wires 120 extend between the structural members 20 and an
anchor 130 fixed into the ground 140 or otherwise fixed (such as an
anchored or weighted body). The guy wires 120 may connect directly
or indirectly to any or all of the structural member 20, the towers
60, the support member 80, or a combination of these
components.
[0059] Referring to FIG. 8, a plurality of internal guy members in
the form of internal wires 150 extend between the structural
members 20 and an anchor 130 fixed into the ground 140 or otherwise
fixed (such as an anchored or weighted body). The internal guy
wires 150 may connect directly or indirectly to the structural
member 20 and/or the towers 60, or a combination of these
components.
[0060] Referring to FIG. 9, the structural members 20 of the
structure 10 may be separated by a gap 160. The gap 160 may be as
small as substantially zero, that is adjacent structural members 20
may abut each other. Typically, the gap 160 would be substantially
uniform along the length of the structure 10, but that is not
required. One or more of the gaps 160 may be used to provide side
access to the structure 10, for example via the side wall door 27
(see FIG. 1)
[0061] Referring to FIG. 10, stiffening members in the form of
cables 50 extend between connectors 60. The connectors 60 are fixed
to the structural member 20.
[0062] Referring to FIG. 11, a rigid structure (in this case, as an
example the side wall door 27 in the form of a rigid frame door
system) may be incorporated into the structure 10. In this FIG. 11,
the flexible membrane 30 (for example the fly 35) is shown as
semi-transparent to better illustrate the structural members
20.
[0063] Referring to FIGS. 12, 14, and 20 a portion of the support
structure 70 may be internal to the structure 10 and another
portion of the support structure 70 may be external to the
structure 10. As show, the support towers 90 extend through the
wall or roof or both of the structure 10 to support the support
member 80 substantially external to the structure 10. Also shown in
FIG. 12, other items may extend through the wall or roof or both of
the structure 10, for example a flare stack 180 or other process
equipment or structures such as pressure vessels, towers, columns,
flare stacks, piping, walkways, pressure relief valves, flare
piping, pipe racks etc.
[0064] Referring to FIG. 13, the structure 10, may include a
non-uniform shape. For example, as shown, the structure 10 may be
shaped to encompass a selected area/space within the structure 10
and/or to avoid a selected area/space outside the structure 10. A
step 190 is one example of such adaptation.
[0065] Referring to FIGS. 15 and 19, a suspended deck 170 may be
provided to improve access to the top area of the structure 10
during the assembly or disassembly. The suspended deck 170 may
include a platform for persons to walk or work on or from during
assembly/disassembly or inspection or maintenance of the structure
10. The suspended deck 170 may also support one or more trolleys,
pulleys, or cranes to lift the columns 40 or flexible membrane 30
etc. during the assembly/dismantle process or maintenance. The
suspended deck 170 could be also equipped with one ore more movable
blower(s) to facilitate snow removal from the upper portion of the
structure 10.
[0066] Referring to FIGS. 17 and 18, one embodiment of a connector
60 is depicted. The connector 60 provides for attachment of the
cable 50 and the-structural member 20. One skilled in the art will
recognize that a variety of apparatus and methods may be used to
affix or join the cables 50 and the structural member 20 (e.g.
elongate pneumatic tubular column 40) of the structure 10 of the
present invention. In one embodiment (not shown) the connector 60
of the type disclosed in the co-pending application U.S. Pat. No.
61/094,727 may be used.
[0067] In erecting or constructing the structure 10 (referring, for
example, to FIGS. 3 and 4) the support member 80 in the form of
suspended cable 100 is extended between the support towers 90. A
plurality of structural members 20 are provided along the length of
the suspended cable 100. The structural members may be separated by
the gap 160, which may be as little as substantially zero metres.
The structural members 20 may be supported from the suspended cable
100 during inflation. A plurality of stiffening members in the form
of cables 50 are connected with the structural members 20 by
connectors 60. The exterior of the structure 10 is covered with a
flexible membrane 30 (for example a fly 35). The interior of the
structure may similarly be covered with a flexible membrane (not
shown).
[0068] A space formed between the structural members 20 and the
flexible membrane 30 may be utilized for the purpose of heating and
ventilation of the structure, for example by forming a channel
which can serve as a conduit for conditioned air (e.g. heated or
cooled).
[0069] In deconstructing, demolishing, or repairing the structure
10 (referring, for example, to FIGS. 3 and 4) at least a portion of
the structure is supported by the support member 80 in the form of
suspended cable 100. At least one structural member 20 is
unsupported (for example by removing any support cables 110) to
form an unsupported structural member 20. The unsupported
structural member 20 may then be removed, repaired or replaced. In
a deconstruction or demolition process, the removal sequence could
be repeated, and once complete, the support member 80 and support
towers 90 removed.
[0070] Thermal and pressure expansion of the elongate pneumatic
tubular columns 40 may be compensated by means of selected sequence
of the assembly and erection of the structure 10.
[0071] The present invention is applicable to a wide variety of
structures including, but not limited to, construction shelters and
storage/maintenance shelters for vehicles and aircraft (including
deployable variants), command centers, disaster relief, housing, or
medical facilities. Such structures may be temporary or
permanent.
[0072] As used herein, cable, wire etc. mean and include a
structural tension element, which may include wire rope, fabric
webbing, metal rods, metal tubulars, fibre reinforced composite
materials such as fibre reinforced plastic, carbon/graphite,
etc.
[0073] Without limiting the scope of the present invention,
generally speaking, the structures 10 having a width up to about 30
m do not require support towers 90, structures 10 having a width
between about 30 m and about 60 m benefit from a support structure
70 having two support towers 90, and that structures 10 having a
width larger than 60 m benefit from a support structure 70 having
four support towers 90.
[0074] In the preceding description, for purposes of explanation,
numerous details are set forth in order to provide a thorough
understanding of the embodiments of the invention. However, it will
be apparent to one skilled in the art that these specific details
are not required in order to practice the invention.
[0075] The above-described embodiments of the invention are
intended to be examples only. Alterations, modifications and
variations can be effected to the particular embodiments by those
of skill in the art without departing from the scope of the
invention, which is defined solely by the claims appended
hereto.
* * * * *