Note: Descriptions are shown in the official language in which they were submitted.
CA 02810538 2013-03-25
METHODS AND APPARATUS FOR FACILITATING RELATIVE
SLIDEABLE MOVEMENT BETWEEN STRUCTURES
Technical Field
[0001] The technology described herein relates to methods and apparatus for
facilitating
relative slideable movement between structures. Particular embodiments relate
to slip
membranes.
Background
[0002] There are many wide varying reasons to provide bores in the ground. By
way of
non-limiting example, such bores can be used for fluid conduits (e.g. gas
pipelines,
aqueducts, sewers and/or the like), accesses to underground regions (e.g.
manhole shafts,
mine shafts, water wells and/or the like), supports for above-grade structures
(e.g.
supports for bridges, buildings, towers, road infrastructure and/or the like)
and/or other
applications. In some cases, the bore may be reinforced with concrete or other
similar
curable construction material, or the interior surface of the bore may be
otherwise
covered with concrete or other similar curable material.
[0003] Sometimes one or more structures may be constructed or inserted within
the bore.
For example, a working platform, elevator shaft, fluid conduit, reinforcement
structure
and/or other structure may be constructed in the bore. The ground may at some
point shift
or move due to settling, seismic activity, flooding, thermal expansion or
contraction, or
other causes. Such movement may cause the bore walls to bend, shift and/or
break. This
can result in structural damage to the one or more structures within the bore.
[0004] Buildings and non-building structures (such as, for example, towers,
piers,
bridges, tunnels, parking structures, and other structures) can also be
subject to
movement. Wind, seismic activity or other ground movement, thermal expansion
or
contraction and/or other factors may cause the structure or parts of the
structure to bend,
shift and/or break and may result in structural damage.
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[0005] There is a general desire for methods and apparatus that address the
aforementioned problems. In particular, there is a desire for methods and
apparatus to
reduce structural damage in the event that structures are subject to external
forces. In
some applications, there may be a desire to provide for relative slideable
movement
Summary
[0006] The technology described herein has a number of aspects. These include,
without
limitation: methods for enabling relative slideable movement between
structures;
methods and apparatus for reducing coefficient of friction and/or breaking
surface tension
[0007] One aspect provides for the placement of one or more slip membranes
between
opposing and adjacent walls of adjacent structures to facilitate relative
slideable
movement between the structures. In some embodiments, one or more of the slip
membranes may be bonded to the wall of a structure.
structures, one of the slip membranes may be made of a material which is
chemically
incompatible with the other one of the slip membranes, causing the slip
membranes to
repel each other. This may help to reduce the coefficient of friction between
the slip
membranes.
20 [0009] Each slip membrane may have a textured or non-smooth surface on
one or both
sides. In some cases, the textured surface may have properties that help to
bond the slip
membrane to the contacting surface (e.g. such as to a concrete wall of a
structure). In
other cases, the textured surface may have properties that help to reduce the
coefficient of
friction between the slip membrane and a contacting surface (e.g. which may be
another
25 slip membrane or the lining or wall of a structure). Features on the
slip membrane's
surface, such as ridges, channels, depressions, furrows and the like, may
assist in
drainage of fluids away from the structures, or may assist in retaining
lubricant material.
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[00101 In addition to the exemplary aspects and embodiments described above,
further
aspects and embodiments will become apparent by reference to the drawings and
by
study of the following detailed descriptions.
Brief Description of Drawings
Figure IA and Figure 1B (together, Figure 1) are respectively isometric and
top
plan sectional views of an exemplary bore in which may be installed a
structure along
with one or more slip membranes according to particular embodiments;
Figure 2 is a partial top plan sectional view of exemplary first and second
structures between which are installed two slip membranes according to one
embodiment;
Figure 3 is a partial top plan sectional view of exemplary first and second
structures between which are installed two slip membranes according to another
embodiment;
Figure 4 is a partial top plan sectional view of exemplary first and second
structures between which are installed three slip membranes according to
another
embodiment;
Figure 5 is a partial top plan sectional view of exemplary first and second
structures between which are installed two slip membranes according to another
embodiment;
Figure 6 is a partial top plan sectional view of exemplary first and second
structures between which are installed three slip membranes according to
another
embodiment;
Figure 7 is a partial top plan sectional view of exemplary first and second
structures between which is installed a slip membrane according to another
embodiment;
Figures 8A, 8B, 8C, 8D, 8E, 8F and 8G (together, Figure 8) are partial top
plan
sectional views of slip membranes according to particular embodiments shown
installed
between exemplary structures;
Figure 9 is a partial top plan sectional view of exemplary first and second
structures between which is installed a slip membrane according to another
embodiment;
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Figure 10 is a partial top plan sectional view of exemplary first and second
structures between which are installed two slip membranes according to another
embodiment; and
Figure 11 is a partial top plan sectional view of exemplary first and second
structures between which is installed a slip membrane according to another
embodiment.
Description
[0012] Throughout the following description, details are set forth in order to
provide a
more thorough understanding to persons skilled in the art. However, well known
elements may not have been shown or described in detail to avoid unnecessarily
obscuring the disclosure. Accordingly, the description and drawings are to be
regarded in
an illustrative, rather than a restrictive, sense.
[0013] Figures 1A and 1B are respectively isometric and top plan sectional
views of an
exemplary bore 10 for which the need may arise for embodiments of the
technology
described herein. Exemplary bore 10 happens to be fabricated in the earth 16
and
happens to be vertically oriented, although this is not necessary. Other bores
may be
fabricated in other materials and/or have other orientations. Bore 10
comprises an interior
bore wall 12 which defines an elongated bore hole 14. In the illustrated
embodiment,
interior bore wall 12 is shaped such that bore hole 14 is generally circular
in cross-
section. Again, however, this is not necessary and embodiments of the
technology
described herein could be used in bores having other cross-sections. In
addition, as
explained below, the need for embodiments of the technology described herein
could
arise in structures other than bores. Particular embodiments of the technology
described
herein may therefore be applied in structures other than bores.
[0014] There are many wide varying reasons to provide bores such as bore 10.
By way of
non-limiting example, such bores can be used for fluid conduits (e.g. gas
pipelines,
aqueducts, sewers and/or the like), accesses to underground regions (e.g.
manhole shafts,
mine shafts, water wells and/or the like), supports for above grade structures
(e.g.
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supports for bridges, buildings, towers, road infrastructure and/or the like)
and/or other
applications.
[0015] In one particular application, bore 10 may be formed as follows: a
cutting tool
may be used to cut a generally annular-shaped cylinder in the ground; the
annular
cylinder may be filled with a temporary filler material (e.g. bentonite clay
or the like) at
about the same time as earth is removed from the annular cylinder. Then,
concrete may
be pumped to the bottom of the annular cylinder, forcing the temporary filler
material out
the top of the annular cylinder. The concrete pumped into the annular cylinder
cures
between the earth that forms the inside and outside surfaces of the annular
cylinder to
provide an annular cylinder of solidified concrete 18 (Figure 1B). The earth
inside
concrete annular cylinder 18 may then be excavated or otherwise removed using
any
suitable means. This excavation creates bore hole 14. Bore hole 14 is defined
by an
interior bore wall 12 which is the interior surface of concrete annular
cylinder 18. Where
annular cylinder 18 originally cut into earth 16 has a generally round cross-
section (as is
the case in the illustrated bore 10 of Figure 1), bore hole 14 may also have a
generally
round cross-section. However, because of the non-homogeneous nature of earth
16 in
which bore 10 is formed, generally annular cylinder 18 and interior bore wall
12
fabricated in this manner may be uneven, rough and may have significant
amounts of
earth, rock and/or other material embedded therein or otherwise stuck thereto.
In addition
to reinforcing bore 10, in some applications, it might be desirable to provide
a bore-hole
defining surface that is relatively smooth and/or uncontaminated in comparison
to interior
bore wall 12.
[0016]The preceding description represents one particular non-limiting
technique for
creating a bore 10 defined by an interior bore wall 12 and having a bore hole
14.
Generally speaking, however, bores like bore 10 may be created by any other
suitable
technique which is known or which may become known in the art, and embodiments
of
the technology described herein should be understood to have application to
any such
=
bores. For the purposes of explanation, the description that follows will
refer to bore 10
of Figure 1, without loss of generality.
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[0017] It is often desirable to reinforce bores, particularly bores formed in
the earth or in
other non-homogeneous or non-stable materials. Such reinforcement can prevent
or
minimize the amount of material from interior bore wall 12 or from the
surrounding
material (e.g. earth 16) which collapses into bore hole 14. Bore reinforcing
structures
may be fabricated in part from concrete or other curable construction
materials. For
example, bore 10 is optionally reinforced to provide a lined reinforcement
structure that
covers at least a portion of an interior wall 12 of bore 10.
[0018] The interior bore wall 12¨along with its reinforcement structure if
bore 10 is
reinforced¨can be considered a first structure. In some cases, a second
structure is
constructed or installed within the bore. For example, a second structure
consisting of a
working platform, elevator shaft, fluid conduit, reinforcement structure
and/or other
structure may be constructed in the bore. The second structure (or portions of
the second
structure) may be constructed such that it is not coupled to or attached to
the first
structure. Parts of the second structure (e.g. an outer wall of the second
structure) may be
located proximate to or in contact with surfaces of the first structure.
[0019] The ground in which the first structure is located may at some point
shift or move
due to settling, seismic activity, flooding, thermal expansion or contraction,
or other
causes. In some cases, the first structure is designed and constructed to
accommodate
some degree of movement. For example, in some cases, the first structure may
be
designed to shift, flex, bend, or otherwise move at various locations upon the
application
of external forces. The movement of the first structure may help to avoid
catastrophic
failure of the entire structure or reduce the structural damage.
[0020] Where a second structure is located within or adjacent a first
structure, the
movement of the first structure may cause the first structure to exert forces
against the
second structure. If the friction between contacting surfaces of the first and
second
structures renders the second structure incapable of moving independently of
the first
structure, the second structure can become damaged.
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[0021] Embodiments of the technology described herein address the
aforementioned
problem through the placement of one or more slip membranes between structures
to
enable relative slideable movement between the structures. The slip membranes
help to
reduce the friction and/or cohesive forces that prevent structures from moving
relative to
one another.
[0022]Figure 2 is a partial top plan sectional view of first and second
structures 20, 22
between which are installed first and second slip membranes 24, 26 according
to one
embodiment. The coefficient of friction between slip membranes 24, 26 is
sufficiently
low so that when forces are applied to cause one or more of structures 20, 22
to move,
slip membranes 24, 26 are capable of sliding relative to one another,
permitting relative
slideable movement of structures 20, 22.
[0023] Each of structures 20, 22 may be a structural wall, pillar, floor,
ceiling, roof or
other structure. For example, first structure 20 may be the interior bore wall
12 of
Figure l's bore 10, forming an "original" or existing structure. Second
structure 22 may
be a "new" structure constructed or installed within bore 10. Structures 20,
22 may be
fabricated in part from concrete or other curable construction materials.
However, this is
not necessary. As described below for other embodiments (for example, the
embodiment
in Figures 9 and 10), structures 20, 22 may be fabricated from other
materials.
[0024] In the illustrated embodiment of Figure 2, first structure 20 includes
an outer
surface leveling layer 20A. To create surface leveling layer 20A, grout,
concrete,
shotcrete, plaster or other suitable curable construction material may be
applied to fill in
the surface irregularities (gaps, voids, crevices and the like) of first
structure 20, forming
a rigid, smooth surface leveling layer 20A once dried. Surface leveling layer
20A is
optional. In other embodiments, first structure 20 does not include a surface
leveling
layer 20A (as illustrated in Figure 3, for example).
[0025] As seen in Figure 2, first structure 20 has an outer surface 20B on
outer surface
leveling layer 20A. Second structure 22 has an outer surface 22B opposing
first structure
20's outer surface 20B. The coefficient of friction between opposing outer
surfaces 20B,
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22B can be quite high. This is typically the case if surface leveling layer
20A is formed of
grout or concrete and second structure 22 is formed of concrete. A high
coefficient of
friction may prevent structures 20, 22 from moving or sliding relative to one
another
when either of these structures is made to move. This may result in structural
damage to
one or both of the structures.
[0026] To facilitate relative slideable movement between structures 20, 22,
slip
membranes 24, 26 may be placed between structures 20, 22. In some embodiments,
one
or both of slip membranes 24, 26 may comprise a plurality of sheets, panels or
sections
that are positioned in a single layer to line a surface of a structure. For
example, a
plurality of panels may be positioned to form a slip membrane 24 lining a
surface 20B of
structure 20. In other embodiments, one or both of slip membranes 24, 26 may
be a
continuous film or sheet. In some applications, it may not be necessary to
cover the entire
surface of a structure with a slip membrane. For example, it may be sufficient
to cover
one or more portions of surface 22B of structure 22 with slip membrane 26.
[0027] Where surfaces 20B, 22B are curved (such as in the illustrated example
of
Figure 2) or irregular in shape, it may be desirable to provide slip membranes
24, 26 that
are sufficiently flexible to contour to the surfaces. In other embodiments
(such as in the
illustrated examples of Figures 6, 9, 10 and 11), the surfaces of the
structures may be
substantially flat or level. In such cases, the slip membranes may be rigid,
semi-rigid or
flexible.
[0028] As seen in Figure 2, first slip membrane 24 is positioned between
structures
20, 22 and adjacent to structure 20's outer surface 20B. In the illustrated
embodiment,
first slip membrane 24 also functions as an additional surface leveling layer
applied to
first structure 20's outer surface 20B. Slip membrane 24 may be made of a
compressible
material such as foam, fabric or other crushable material. In such
embodiments, when slip
membrane 24 is bonded, adhered, or otherwise attached to first structure 20,
the material
at slip membrane 24's side 24B can fill in any surface irregularities (gaps,
voids, crevices
and the like) present at first structure 20's outer surface 20B. This creates
a smoother
surface and may reduce the coefficient of friction between slip membranes 24,
26.
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[0029] Second slip membrane 26 is placed between first slip membrane 24 and
second
structure 22's outer surface 22B. Slip membrane 26 may be bonded, adhered or
otherwise
attached to second structure 22's outer surface 22B. In some applications, the
material
used for slip membrane 26 may have certain properties which make it chemically
incompatible with the material of slip membrane 24. This can result in slip
membranes
24, 26 repelling one another, which can help to reduce the coefficient of
friction between
slip membranes 24, 26. Slip membranes 24, 26 may be made of one or more
materials
that contribute to sliding (e.g. they are materials that are inherently
slippery and have low
coefficient of friction) and tend to cause the sliding surfaces to repel one
another.
[0030] First slip membrane 24 has a first side or surface 24A which is
adjacent to (and in
contact with) second slip membrane 26, and a second side or surface 24B which
is
adjacent to structure 20's outer surface 20B. Second slip membrane 26 has a
first side or
surface 26A which is adjacent to (and in contact with) first slip membrane 24,
and a
second side or surface 26B which is adjacent to structure 22's outer surface
22B. Slip
membranes 24, 26 can move relative to one another if the frictional forces
between
contacting sides 24A, 26A are overcome. Slip membranes 24, 26 may move in a
number
of different directions. The directions of movement may be constrained by the
geometry
of the structures. For example, in the case of vertically-oriented annular
cylindrical
structures 20, 22 as may be installed for Figure l's bore 10, one of slip
membranes 24, 26
may slide relative to the other in a vertical direction (i.e. up or down)
and/or may rotate
about an axis of bore 10. Slip membranes 24, 26 may move generally in a plane
defined
by slip membranes 24, 26 at their contacting surfaces.
[0031] It is desirable to have a low coefficient of friction between slip
membranes 24, 26,
to facilitate relative movement between structures 20, 22. In some
applications, for
example, it may be desirable that the coefficient of static friction is below
0.6. In some
other applications, it may be desirable that the coefficient of static
friction is below 0.25.
In particular applications, it may be desirable that the coefficient of static
friction
approaches 0.1 or is 0.1 or below. In some applications, different thresholds
may apply
for the coefficient of kinetic friction. For example, the coefficient of
kinetic friction may
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not need to be as low as the coefficient of static friction. Suitable
materials may be
selected for slip membranes 24, 26 so that the desired values of coefficients
of friction are
achieved between the contacting surfaces 24A, 26A of slip membranes 24, 26.
[0032] By way of non-limiting example, materials that may be used for slip
membranes
24, 26 include polyethylene, polypropylene or other plastics, silicone,
ceramics, foam,
metal, and woven or non-woven textiles. First slip membrane 24 may be made of
one or
more different materials from second slip membrane 26. As discussed above,
slip
membranes 24, 26 may be made of chemically incompatible materials.
[0033] As discussed above, in the Figure 2 embodiment, slip membranes 24, 26
may be
bonded, adhered or otherwise attached to structures 20, 22 respectively,
providing a slip
interface or sliding interface between slip membranes 24, 26, but not between
slip
membrane 24 and first structure 20, or between slip membrane 26 and second
structure
22. The bonding of slip membranes 24, 26 to adjacent structures is not
necessary for all
embodiments. In other embodiments, an additional sliding interface may be
provided
between a slip membrane and the adjacent structure by not bonding the slip
membrane to
the structure. For example, in the Figure 2 embodiment, if slip membrane 24 is
not
bonded to structure 20, then slip membrane 24 would be free to slide relative
to first
structure 20 if the friction between first structure 20's surface 20B and slip
membrane
24's surface 24B is overcome. Similarly, in the Figure 2 embodiment, if slip
membrane
26 is not bonded to structure 22, then slip membrane 26 would be free to slide
relative to
second structure 22 if the friction between second structure 22's surface 22B
and slip
membrane 26's surface 26B is overcome. Therefore, in the Figure 2 embodiment,
there
can be up to three sliding interfaces if the slip membranes are not bonded to
their adjacent
structures: one between the slip membranes' contacting surfaces 24A, 26A, one
other
between first structure 20's surface 20B and slip membrane 24's surface 24B,
and one
other between second structure 22's surface 22B and slip membrane 26's surface
26B. In
certain embodiments, the coefficient of friction between slip membrane 24 and
first
structure 20 or between slip membrane 26 and second structure 22 may not need
to be as
low as the coefficient of friction between slip membranes 24, 26, since the
contacting
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surfaces 24A, 26A between slip membranes 24, 26 may act as the primary sliding
interface.
[0034] One or both of slip membranes 24, 26 may be formed of different
materials and/or
have different properties at each side. For example, side 24B of first slip
membrane 24
may be made of a certain material and have various properties that make it
suitable for
bonding to first structure 20's outer surface 20B. In other embodiments where
first slip
membrane 24 is not bonded to first structure 20 given that a sliding interface
is intended
between first slip membrane 24 and first structure 20, side 24B of first slip
membrane 24
may be made of a material and have various properties that make it suitable
for sliding
relative to first structure 20's outer surface 20B. The other side 24A of slip
membrane 24
(i.e. the side that contacts second slip membrane 26) may be made of a
different material
and have various other properties that, when factored together with the
particular material
and various properties of side 26A of slip membrane 26, serve to keep the
coefficient of
friction against side 26A of slip membrane 26 below a threshold value. Side
26B of
second slip membrane 26 may be made of a material and have various properties
that
make it suitable for bonding to second structure 22's outer surface 22B. In
other
embodiments where second slip membrane 26 is not bonded to second structure 22
given
that a sliding interface is intended between second slip membrane 26 and
second
structure 22, side 26B of second slip membrane 26 may be made of a material
and have
various properties that make it suitable for sliding relative to second
structure 22's outer
surface 22B. The other side 26A of second slip membrane (i.e. the side that
contacts first
slip membrane 24) may be made of a different material and have various
properties that,
when factored together with the particular material and various properties of
side 24A of
slip membrane 24, serve to keep the coefficient of friction against side 24A
of slip
membrane 24 below a threshold value.
[0035] The materials or composition of each slip membrane (or each side of a
slip
membrane) may be selected or designed to take into account the characteristics
or
properties of any surfaces or materials which contact the slip membrane. For
example, if
it is known that one side of a slip membrane will contact and be required to
bond with a
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,
=
structural wall formed of concrete, but the other side of the slip membrane
will contact
and be required to slide relatively freely against a textile material, then a
material which
may be suitable for use as the slip membrane is one that bonds to concrete,
but also repels
and has a low coefficient of friction against the textile material. In other
applications, it
may be desirable to use different materials for each side of a slip membrane
so that the
desired response is achieved at each side (e.g. bonding or sliding). Exemplary
slip
membranes are shown and described below with reference to Figure 8.
[0036] In some embodiments, to enhance the sliding properties of a slip
membrane, a
paint or film may be applied to one or both sides of a slip membrane. For
example, in the
Figure 2 embodiment, a paint or film may be applied to slip membrane 24's
surface 24A
and/or to slip membrane 26's surface 26A to decrease the coefficient of
friction between
slip membranes 24, 26. Suitable paints that may be used for this purpose may
include, for
example, PVC paint. Suitable films that may be used for this purpose may
include, for
example, polyurethane films or PVC films. Such films may be laminated,
coextruded
with, or otherwise applied to the slip membrane prior to installation of the
slip membrane.
[0037] Figure 3 is a partial top plan sectional view of first and second
structures 20, 22
between which are installed first and second slip membranes 24, 26' according
to another
embodiment. The Figure 3 embodiment is similar in some respects to the Figure
2
embodiment, and similar reference numerals are used in the description herein
and the
drawings to refer to the similar components (including, for example, first
structure 20,
second structure 22, first structure 20's outer surface 20B, and second
structure 22's outer
surface 22B). The Figure 2 description applies also to the similar components
in the
Figure 3 embodiment. The Figure 3 embodiment does not include a surface
leveling layer
20A as shown in Figure 2. The Figure 3 embodiment also differs from the Figure
2
embodiment in that Figure 3's second slip membrane 26' includes a plurality of
bumps 30
on the surface of slip membrane 26' which is adjacent to first slip membrane
24 (i.e. on
side 26A of slip membrane 26'). Bumps 30 extend toward and may contact side
24A of
slip membrane 24 as spaced apart locations on side 24A. By way of non-limiting
example, bumps 30 may consist of ridges, round or hemispherical protrusions,
beads, or
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protrusions in other shapes. Bumps 30 may be formed in a regular (e.g.
directional) or
irregular (e.g. random) pattern onside 26A of slip membrane 26.
[0038] Bumps 30 may serve one or more purposes. In some applications, bumps 30
may
be useful to help reduce the coefficient of friction between slip membranes
24, 26'. In
some applications, bumps 30 provide a textured or non-smooth surface on slip
membrane
26' to permit fluid to flow interspatially and help break the surface tension
that would
otherwise bond membranes 24, 26' together in the event that water (or other
fluid) is
trapped in the spaces between the membranes. In other applications, bumps 30
may be
useful to help with the drainage of fluids away from slip membranes 24, 26'
and
structures 20, 22. If bumps 30 are sufficiently rigid, then they can provide
channels,
valleys and the like (between the bumps) in which fluid may be drained away
from the
structures.
[0039] In other embodiments, it may be desirable to maintain lubricant or
other fluids
between the membrane and an adjacent surface. For example, in the Figure 3
embodiment, lubricant may be introduced by way of gravity or pressure into the
spaces
around bumps 30 in order to contribute to a reduction in the coefficient of
friction
between surface 26A' of slip membrane 26' and surface 24A of slip membrane 24.
Bumps 30 may help to retain the lubricant in the spaces between slip membranes
24, 26.
[0040] In certain applications, bumps 30 may be useful for a combination of
the purposes
described above¨i.e. reducing coefficient of friction, breaking surface
tension, and/or
facilitating drainage (or alternately, receiving and retaining lubricant to
facilitate
movement between the structures).
[0041] As with the Figure 2 embodiment, in the Figure 3 embodiment one or both
of slip
membranes 24, 26' may be bonded to an adjacent structure. However, there can
be up to
three sliding interfaces in certain embodiments if the slip membranes are not
bonded to
their adjacent structures: one between the slip membranes' contacting surfaces
24A,
26A', one other between surface 20B of first structure 20 and surface 24B of
first slip
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membrane 24, and one other between surface 22B of second structure 22 and
surface
26B' of second slip membrane 26'.
[0042] Figure 4 is a partial top plan sectional view of first and second
structures 20, 22
between which are installed first, second and third slip membranes 24, 26, 28
according
to another embodiment. The Figure 4 embodiment is similar in some respects to
the
Figure 2 and 3 embodiments, and similar reference numerals are used in the
description
herein and the drawings to refer to the similar components (including, for
example, first
structure 20, second structure 22, surface leveling layer 20A, first structure
20's outer
surface 20B, and second structure 22's outer surface 22B). The Figure 2
description
applies also to the similar components in the Figure 4 embodiment. The Figure
4
embodiment differs from the Figure 2 and 3 embodiments in that the Figure 4
embodiment includes a third slip membrane 28 placed between first and second
structures
20, 22.
[0043] As seen in Figure 4, third slip membrane 28 may be positioned between
first and
second slip membranes 24, 26. Slip membrane 28 is preferably not bonded to any
of the
adjacent surfaces, so that slip membrane 28 can slide relative to the adjacent
or
contacting surface on either side. The inclusion of third slip membrane 28
provides
sliding surfaces on either side of slip membrane 28, in order to facilitate
relative
movement of structures 20, 22.
[0044] Slip membrane 28 has a first side 28A in contact with side 24A of first
slip
membrane 24. Slip membranes 24, 28 can move relative to one another if the
frictional
forces between sides 24A, 28A are overcome. Slip membrane 28 has a second side
28B
in contact with side 26A of second slip membrane 26. Slip membranes 26, 28 can
move
relative to one another if the frictional forces between sides 26A, 28B are
overcome. Slip
membrane 28 may be made of a material that is chemically incompatible with the
materials of slip membranes 24, 26, so as to repel these slip membranes and
reduce the
coefficient of friction between sides 24A, 28A and between sides 26A, 28B.
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[0045] By way of non-limiting example, materials that may be used for slip
membranes
24, 26, and 28 of Figure 4 include polyethylene, polypropylene or other
plastics, silicone,
ceramics, foam, metal, and woven or non-woven textiles. Suitable materials may
be
selected for slip membranes 24, 26 and 28 so that the desired values of
coefficients of
friction are achieved between slip membranes 24, 28 and between slip membranes
26, 28.
[0046] As with slip membranes 24, 26, for some applications slip membrane 28
may be
formed of different materials and/or have different properties at each of
sides 28A, 28B.
The materials or composition of each side of slip membrane 28 may be selected
or
designed to take into account the characteristics or properties of the
surfaces or materials
which contact the slip membrane. For example, side 28A of slip membrane 28
(i.e. the
side that contacts first slip membrane 24) may be made of a certain material
and have
various properties that serve to keep the coefficient of friction against side
24A of slip
membrane 24 below a threshold value. The other side 28B of slip membrane 28
(i.e. the
side that contacts second slip membrane 26) may be made of a different
material and
have various properties that serve to keep the coefficient of friction against
side 26A of
slip membrane 26 below a threshold value.
[0047] One advantage of including slip membrane 28 is that it provides dual
sliding
interfaces¨one on each of sides 28A, 28B of membrane 28, as described above.
Having
more than one sliding interface may provide additional opportunities for the
structures to
slip against one another, thereby reducing the overall coefficient of friction
between the
structures.
[0048] In some applications, dual sliding interface may be provided as shown
in Figure 4,
with each sliding interface customized for a different application. For
example, some
materials may have low friction between them when dry, but will not slide as
easily when
they are wet. Other materials may have low friction between them when wet, but
will not
slide as easily when they are dry. So that structures 20, 22 are able to
overcome friction
whether or not there is fluid between the structures, one sliding interface
may be made
more suitable for dry sliding while another sliding interface may be made more
suitable
for wet sliding by choosing appropriate materials for each of the contacting
sides of the
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CA 02810538 2013-03-25
=
slip membranes in each case. In this manner, even if one sliding interface
becomes
"stuck" because the materials do not slide easily in the particular
circumstances, the other
sliding interface may still enable relative movement between the structures.
[0049] In other embodiments, more than two sliding interfaces may be provided
between
structures with the installation of additional sliding membranes. In
particular, a plurality
of slip membranes may be positioned between structures 20, 22 so that a total
of 3, 4 or
more sliding interfaces may be provided (i.e. one between each pair of
adjacent slip
membranes). As discussed above with reference to Figures 2 and 3, additional
sliding
interfaces may be provided between an outermost slip membrane (such as slip
membrane
26 or slip membrane 24 in Figure 4) and the adjacent structure if the slip
membrane is not
bonded to the structure.
[0050] Figure 5 is a partial top plan sectional view of first and second
structures 20, 22
between which are installed first and second slip membranes 24, 26" according
to
another embodiment. The Figure 5 embodiment is similar in some respects to the
Figure
3 embodiment, and similar reference numerals are used in the description
herein and the
drawings to refer to the similar components (including, for example, first
structure 20,
second structure 22, first structure 20's outer surface 20B, and second
structure 22's outer
surface 22B). The Figure 3 description applies also to the similar components
in the
Figure 5 embodiment. However, the Figure 5 embodiment differs from the Figure
3
embodiment in that Figure 5's second slip membrane 26" includes a plurality of
hairs or
fibres 32 on the surface of slip membrane 26" which is adjacent to first slip
membrane 24
(i.e. on side 26A of slip membrane 26"). Hairs 32 extend toward and may
contact side
24A of slip membrane 24. Slip membrane 26" may be made of a textile material.
An
optional lubricant material 33 may be applied between slip membranes 24, 26"
to reduce
the coefficient of friction between these layers.
[0051] As with the bumps 30 shown in the Figure 3 embodiment, hairs 32 of the
Figure 5
embodiment may serve one or more purposes. In some applications, hairs 32 may
be
useful to help reduce the coefficient of friction between slip membranes 24,
26". Hairs
32 may also be useful to help break the surface tension that would otherwise
bond
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CA 02810538 2013-03-25
=
membranes 24, 26" together in the event that water or other liquid is trapped
between the
membranes. In some applications, hairs 32 may be sufficiently rigid to provide
spaces
and channels useful to help with the drainage of fluids away from slip
membranes 24,
26" and structures 20, 22. In other applications where lubricant material 33
is introduced
between slip membranes 24, 26", hairs 32 may be useful to help retain
lubricant material
33 or other fluids to contribute to a reduction in the coefficient of
friction.
100521In particular embodiments, hairs 32 may be oriented primarily in a
single
direction (at an angle to slip membrane 26") to permit sliding of slip
membrane 26" in
only one direction. In other embodiments, hairs 32 may be oriented in
different directions
or in a direction perpendicular to slip membrane 26" to enable sliding of slip
membrane
26" in more than one direction.
[0053] Figure 6 is a partial top plan sectional view of first and second
structures 20, 22
between which are installed first, second and third slip membranes 24, 26, 28
according
to another embodiment. The Figure 6 embodiment is similar in some respects to
the
Figure 4 embodiment, and similar reference numerals are used in the
description herein
and the drawings to refer to the similar components (including, for example,
first
structure 20, second structure 22, surface leveling layer 20A, first structure
20's outer
surface 20B, and second structure 22's outer surface 22B). The Figure 4
description
applies also to the similar components in the Figure 6 embodiment. The Figure
6
embodiment differs from the Figure 4 embodiment in that the walls of the
Figure 6
structures 20, 22 are not curved. In the Figure 6 embodiment, structures 20,
22 are square
or rectangular structures (a corner of each structure is shown in Figure 6).
Figure 6
illustrates that slip membranes 24, 26, 28 can also be used with non-
cylindrical or non-
curved structures to facilitate relative movement between such structures.
Slip
membranes 24, 26, 28 of Figure 6 may have similar characteristics and be
installed and
function in a similar manner to the slip membranes described with respect to
Figure 4. In
other embodiments, slip membranes 24, 26, 28 may be installed between other
non-
cylindrical or non-curved structures such as sections of flat opposing
surfaces or walls.
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CA 02810538 2013-03-25
[0054] Figure 7 is a partial top plan sectional view of first and second
structures 20, 22
between which is installed a slip membrane 26 according to one embodiment. The
Figure
7 embodiment is similar in some respects to the Figure 2 embodiment, and
similar
reference numerals are used in the description herein and the drawings to
refer to the
similar components (including, for example, first structure 20, second
structure 22, first
structure 20's outer surface 20B, and second structure 22's outer surface
22B). The
Figure 2 description applies also to the similar components in the Figure 7
embodiment.
The Figure 7 embodiment differs from the Figure 2 embodiment in that Figure 7
shows a
stay-in-place form 34 that is used to fabricate structure 20. For example,
form 34 may be
assembled next to an interior bore wall 12 (or other wall), and then concrete
21 or other
curable material is poured into form 34 to fill the space between form 34 and
interior bore
wall 12. Form 34 may be assembled by connecting together panels or sections
that are
made of plastic, metal or other rigid material. By way of example, form 34 may
comprise
a form for lining a concrete-reinforced bore (and may optionally be lined) as
described in
the applicant's Canadian patent application No. 2,714,763 filed on September
20, 2010,
and entitled "SYSTEMS AND METHODS FOR PROVIDING A CONCRETE-
REINFORCED BORE". However, this is not necessary. In other embodiments, other
suitable forms, including forms for applications other than a concrete-
reinforced bore,
may be installed as form 34 in Figure 7. For example, a form may be fabricated
to line or
cover a wide variety of existing structures including a bore, tank, wall,
column, or
structures of different shapes that may be curved or round or be comprised of
two or
more relatively flat surfaces.
[0055] In the Figure 7 embodiment, slip membrane 26 is positioned between form
34 and
structure 22. Figure 7's slip membrane 26 may have similar characteristics to
Figure 2's
slip membrane 26. Slip membrane 26 functions to provide relative slideable
movement
between structure 20 (including form 34) and structure 22. In some
embodiments, slip
membrane 26 is bonded to structure 22 or to form 34, and provides a sliding
interface on
the side of slip membrane 26 that is not bonded. In other embodiments, slip
membrane 26
is not bonded to either structure 22 or form 34, and provides for a sliding
interface on
either side of the slip membrane. Slip membrane 26 may be made of a certain
material
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CA 02810538 2013-03-25
=
and have various properties that serve to keep the coefficient of friction
between slip
membrane 26 and adjacent sliding surfaces (such as on form 34) below a
threshold value.
[0056] To reduce the coefficient of friction and facilitate sliding between
structures 20,
22 in the Figure 7 embodiment, in some cases a paint or film may be applied to
one or
both sides of slip membrane 26, and/or to the side of form 34 that is adjacent
to slip
membrane 26. In the Figure 7 embodiment, a paint coating 27 is applied to form
34.
Suitable paints that may be used for this purpose may include, for example,
PVC paint.
Suitable films that may be used for this purpose may include, for example,
polyurethane
films or PVC films. Such films may be laminated, coextruded with, or otherwise
applied
to slip membrane 26 or the panels or sections of form 34.
[0057] Figure 8 shows partial top plan sectional views of slip membranes
according to
particular embodiments installed between structures 20, 22. Figure 8A shows a
slip
membrane 40 made of foam and haying a rippled or corrugated surface 40A on one
side.
Figure 8B shows a slip membrane 42 having fibers or hairs extending from side
42A.
Figure 8C shows a slip membrane 44 made of fabric.
[0058] Figures 8D and 8E show different embodiments of corrugated slip
membranes 52,
54, respectively, between first and second structures 20, 22. Slip membranes
52, 54 have
a corrugated or rippled surface such that most of the surface area of first
structure 20 is
not in contact with slip membranes 52, 54; as seen in Figures 8D and 8E only
the peaks
of the corrugated surface are in contact with first structure 20.
[0059] Figure 8F shows a smooth slip membrane 46 made of a low friction
material (e.g.
polyethylene, polypropylene). Figure 8G shows textured slip membranes 47, 48.
Slip
membranes 47, 48 have bumps, protrusions or ridges. Slip membrane 47 has a
random
textured pattern 49 on its surface. Slip membrane 48 has a directional
textured pattern 50
on its surface. One or more of the slip membranes illustrated in Figure 8 may
be used in
the embodiments described herein to reduce coefficient of friction and
facilitate relative
slideable movement between structures.
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CA 02810538 2013-03-25
[0060] Figure 9 is a partial top plan sectional view of first and second
structures 20', 22'
between which is installed a slip membrane 28' according to another
embodiment. Slip
membrane 28' functions to reduce the coefficient of friction and enable
relative slideable
movement between structures 20', 22'. Unlike the examples described above,
structures
20', 22' of Figure 9 are structural walls that may be made of brick, concrete,
stone,
concrete masonry unit (CMU), steel, wood, soil, gravel or a combination of any
of these
materials. As shown in Figure 9, optional surface leveling layers 20A', 22A'
(formed of
grout, concrete, shotcrete, plaster or other suitable curable construction
material) may be
applied at opposing and adjacent sides of structures 20', 22' respectively. A
slip
membrane 28' is placed between surface leveling layers 20A', 22A'. The slip
membrane 28' of Figure 9 may have similar characteristics to the slip membrane
28 of
Figure 4, and provides dual sliding interfaces, i.e. one on either side of the
membrane.
The materials and composition of each side of the Figure 9 slip membrane 28'
may be
selected or designed to take into account the characteristics or properties of
the surfaces
or materials which contact the slip membrane.
[0061] In other embodiments, slip membrane 28' is bonded to one of structures
20', 22',
resulting in only one sliding interface (i.e. on the side that is not bonded
to a structure).
[0062] Figure 10 is a partial top plan sectional view of first and second
structures 20', 22'
between which are installed two slip membranes 28, 29 according to another
embodiment. The example of Figure 10 is similar in many respects to the
example of
Figure 9, except that Figure 10 includes two slip membranes as opposed to the
one shown
in Figure 9. Slip membranes 28, 29 may be made of chemically incompatible
materials so
that they repel one another and have a low coefficient of friction. One or
both of slip
membranes 28, 29 is optionally bonded to surface leveling layers 20A', 22A',
respectively.
[0063] Figure 11 is a partial top plan sectional view of first and second
structures 20",
22" between which is installed a single slip membrane 28" according to another
embodiment. Structures 20", 22" may be structural walls that are made of
brick,
concrete, stone, concrete masonry unit (CMU), steel, wood, soil, gravel or a
combination
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of any of these materials. Slip membrane 28" is made from one or more
materials having
a low coefficient of friction against structures 20", 22". Slip membrane 28"
may be
formed of different materials and/or have different properties at each side.
For example,
side 28A" of slip membrane 28" may be made of a certain material and have
various
properties that keep the coefficient of friction against structure 20" below a
threshold
value. Likewise, side 28B" of slip membrane 28" may be made of a certain
material and
have various properties that keep the coefficient of friction against
structure 22" below a
threshold value. In some embodiments, one side of slip membrane 28" is
optionally
bonded to one of structures 20", 22", providing a sliding surface only on the
other side of
slip membrane 28" (i.e. on the side that is not bonded to a structure).
[0064] As will be appreciated by a person of skill in the art, to facilitate
relative slideable
movement between structures, any of the slip membranes described herein may
have one
or more of the characteristics or properties of a slip membrane described in
another
embodiment. By way of non-limiting example, slip membrane 28" of Figure 11 may
have characteristics of any one or more of slip membranes 24, 26 of Figure 2,
slip
membrane 26' of Figure 3, slip membrane 28 of Figure 4, or slip membrane 26"
of
Figure 5.
[0065] While the drawings show one or more slip membranes on one side of a
first
structure 20 and an adjacent side of a second structure 22, in some
applications it may be
desirable to position one or more slip membranes on both sides of a structure.
For
example, in some applications, where an existing structure is adjacent to or
in contact
with another structure on each opposing side of the existing structure, one or
more slip
membranes may be installed against each side of the existing structure in
order to
facilitate relative slideable movement between the existing structure and each
of the
adjacent structures. In some other applications, it may be desirable to
install slip
membranes on additional sides of a structure (e.g. around the four outer
and/or inner
walls of a rectangular structure). One or more slip membranes according to the
embodiments described herein may be installed wherever it is desirable to
reduce
coefficient of friction (and/or break surface tension in the case of liquid
being trapped
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= CA 02810538 2013-03-25
=
between the surfaces) and enable relative slideable movement between adjacent
structures, surfaces or walls.
[0066] Where a component (e.g. structure, wall, lining, membrane, sheet,
panel,
protrusion, ridge, channel, form, etc.) is referred to above, unless otherwise
indicated,
reference to that component (including a reference to a "means") should be
interpreted as
including as equivalents of that component any component which performs the
function
of the described component (i.e., that is functionally equivalent), including
components
which are not structurally equivalent to the disclosed structure which perform
the
function in the illustrated exemplary embodiments.
[0067] The slip membranes in each embodiment are referred to herein as a
"first" slip
membrane, "second" slip membrane, "third" slip membrane, etc. Similarly, the
structures
are referred to herein as a "first" structure and "second" structure. It is to
be understood
that the labels of "first", "second", "third", etc. are chosen for convenience
(e.g. chosen
based on the order in which the components are introduced in the specification
or in the
claims) and do not necessarily correspond to the order in which any particular
slip
membrane, structure or other component may be installed or positioned. In
addition, the
references to a "first", "second" or "third" slip membrane may be specific to
each
embodiment. For example, a "first" slip membrane in one embodiment may be
equivalent to a slip membrane that is referred to as a "second" or "third"
slip membrane
in another embodiment, or in one of the claims.
[0068] As will be apparent to those skilled in the art in the light of the
foregoing
disclosure, many alterations and modifications are possible. For example:
= The illustrated embodiments of Figures 3, 5 and 8 show a textured surface
(bumps, hairs or other texture) on one side of a slip membrane. In other
embodiments, a textured surface may be provided on both sides of a slip
membrane. The textured surface on one side of a slip membrane may be the same
or different from the textured surface on the opposite side.
= In some of the embodiments described above, one or more of the slip
membranes
are bonded to adjacent structures. In particular embodiments, a slip membrane
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. CA 02810538 2013-03-25
*
may be semi-bonded to an adjacent structure such that gaps or voids are left
between the slip membrane and the structure's surface. This can provide the
advantage of allowing excess moisture to drain out between the slip membrane
and the adjacent structure.
= While the slip membranes are generally shown to be installed between
structures
in the illustrated embodiments, in other embodiments slip membranes may be
installed between components such as floors, walls, ceilings, columns and the
like. One or more slip membranes according to the embodiments described herein
may be installed wherever it is desirable to enable relative slideable
movement
between adjacent surfaces.
= The thickness of the slip membranes may vary between embodiments. The
material and thickness for each slip membrane can be chosen to provide the
desired rigidity or flexibility, coefficient of friction, and other
characteristics
suitable for the particular application.
100691 While a number of exemplary aspects and embodiments have been discussed
above, those of skill in the art will recognize certain modifications,
permutations,
additions and sub-combinations thereof. It is therefore intended that the
scope of the
following appended claims and claims hereafter introduced should not be
limited by the
preferred embodiments set forth in the examples, but should be given the
broadest
interpretation consistent with the description as a whole.
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