U.S. patent application number 10/841176 was filed with the patent office on 2005-01-13 for expansion and seismic joint covers.
Invention is credited to Baerveldt, Konrad.
Application Number | 20050005553 10/841176 |
Document ID | / |
Family ID | 33563585 |
Filed Date | 2005-01-13 |
United States Patent
Application |
20050005553 |
Kind Code |
A1 |
Baerveldt, Konrad |
January 13, 2005 |
Expansion and seismic joint covers
Abstract
A seismic/expansion joint seal and cover comprising a cover
plate, a central spine extending downwardly from the cover plate,
and at least one layer of a resilient compressible foam sealant on
each side of the spine.
Inventors: |
Baerveldt, Konrad; (Toronto,
CA) |
Correspondence
Address: |
RANDALL J. KNUTH P.C.
3510-A STELLHORN ROAD
FORT WAYNE
IN
46815-4631
US
|
Family ID: |
33563585 |
Appl. No.: |
10/841176 |
Filed: |
May 6, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10841176 |
May 6, 2004 |
|
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10318721 |
Dec 13, 2002 |
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Current U.S.
Class: |
52/459 ;
52/167.1 |
Current CPC
Class: |
E04B 1/6804 20130101;
E01D 19/06 20130101 |
Class at
Publication: |
052/459 ;
052/167.1 |
International
Class: |
E04C 003/00 |
Claims
1. A seismic/expansion joint seal and cover comprising: a cover
plate; a central spine extending downwardly from said cover plate;
and at least one layer of a resilient compressible foam sealant on
each side of said spine.
2. A joint and cover as claimed in claim 1, wherein said cover is
detachable from said spine.
3. A joint seal and cover a claimed in claim 2, wherein said cover
is screwed to said spine.
4. A joint seal and cover as claimed in claim 3, wherein said spine
is composed of two mirror-image generally C-shaped members, each of
which has a lower base flange, an upper base flange into which said
cover is screwed, and a flat web extending between the flanges,
against which said foam sealant is positioned.
5. A joint seal and cover as claimed in claim 4, wherein said
C-shaped members are separated by a strip of incompressible
foam.
6. A joint seal and cover as claimed in claim 2, wherein a bead of
sealant is applied between said spine and said cover.
7. A joint seal and cover as claimed in claim 3, wherein a bead of
sealant is applied between said spine and said cover.
8. A joint seal and cover as claimed in claim 4, wherein a bead of
sealant is applied between said spine and said cover.
9. A joint seal and cover as claimed in claim 5, wherein a bead of
sealant is applied between said spine and said cover.
10. A joint seal and cover as claimed in claim 9, wherein said
layer of resilient compressible foam on each side of said spine is
discontinuous, and a waterproof membrane is provided above said
spine, beneath said cover.
11. A joint seal and cover as claimed in claim 10, including clips
for connecting the edges of said waterproof membrane to the edges
of a joint.
12. A joint seal and cover as claimed in claim 11, wherein said
resilient compressible foam sealant is provided in discrete
segments on each side of said spine, separated by spaces up to
twice the length of said discrete segments.
13. A joint seal and cover as claimed in claim 12, wherein said
membrane is a folded bellows type membrane.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to the field of seismic and
expansion joint covers.
[0003] 2. Description of the Related Art
[0004] Expansion and seismic joint covers are, essentially, covers
or mechanism devices to cover expansion and seismic joints to
provide pedestrian or vehicular passage over a joint, and provide a
smooth transition from one slab to another, while not inhibiting
joint movement or restricting this movement as a result of the
mechanism employed. Generally, the mechanisms employed to position
the expansion/seismic joint cover over the joint are either of a
mechanical nature or make use of an elastic and recoverable element
to provide the impetus (spring-memory or return-force) to maintain
the joint cover in a median position relative to the joint
movements occurring. These movements may be experienced in al three
planes, such as expansion and contraction, deflection and shear of
the joint.
[0005] Various mechanisms are thus employed to deal with this three
directional movement and the mechanism to stabilize the expansion
joint cover and restore it into a "neutral position" relative to
the movement that has taken place.
[0006] FIG. 1 is a typical prior art expansion/seismic joint cover
manufactured by Migua Fugensysteme GmbH & Co. KG, in Germany
particularly for Seismic Joints. As can be seen, this has a cover
plate extending across the width of the joint to allow for both
vehicular and pedestrian traffic. As a self-centering mechanism, it
utilizes the recovery ability of elastomeric extrusions. These
extrusions exert the return force required to reposition the cover
plate as a result of movements occurring in the joint. The dotted
line, seen midway through the joint, is a horizontal bar set across
the width of the joint to act as a stabilizing element for the
elastomeric extrusions in the center. It is there to add stability
to the joint and allow the central (metallic) part of the joint to
be fastened to the cover plate, prior to its (the horizontal bar)
removal. This expansion/seismic joint cover is intended to be
watertight. The waterproofing is confined substantially to the
upper surfaces of the joint immediately below the cover plate.
However, once the horizontal (stabilizing) bar is removed, remedial
work on the joint is difficult as removal of the cover plate will
allow the central portion of the joint to collapse as it is no
longer supported (by the horizontal bar).
[0007] FIG. 2 shows an expansion/seismic joint made by Watson
Bowman Acme Corp., in the U.S.A. In this design, the cover plate is
attached to a scissors-type mechanical device immediately below it.
The scissors-type mechanism is similar to a "pantograph" or
expanding scissors type hot-plate mat. In other words, a
scissors-type movement contained between nylon bearings and running
the length of the joint. In this type of mechanism, an increase or
decreases in the joint width will result in the repositioning of
the cover plate along the center line. However, this
expansion/seismic joint cover is not watertight immediately below
the cover plate--as in the case with the expansion/seismic joint
cover in FIG. 1. Thus, an elaborate system of gutters attempts to
provide a solution to the watertight issue. The joint, in effect,
suffers from three major problems. Firstly, an inability to inspect
and clean out the joint other than by removal of the whole joint
assembly (the scissors mechanism prevents direct access into the
joint below the cover or slide plate). Secondly, the ingress of
waterborne salts into the joint will seriously affect the long term
performance of the self-centering mechanism. Thirdly, the joint
design lacks "watertight properties".
[0008] The above prior art illustrated two objects of the present
invention. The first is that the cover plate should be removable to
permit inspection of the joint below. The second object is that the
joint should be watertight at, or immediately below, the line of
waterproofing that is applied to the deck. This will ensure a
waterproofing line of integrity across both decks, on either side
of the joint, and through the actual joint itself.
[0009] It can be seen from FIGS. 1 and 2 that the emphasis, until
this point in time, has been to utilize either a mechanical
mechanism or elastomeric extruded profile as the correcting or
centering element required to maintain the cover plate in its
correct position relative to joint movement occurring beneath it.
In other words, the cover plate cannot be allowed to merely sit on
the surface of the joint but must be guided to maintain a central
position or neutral position relative to the joint movement
occurring.
SUMMARY OF THE INVENTION
[0010] In the present invention, then, the present invention
relates to a seismic/expansion joint seal and cover comprising a
cover plate, a central spine extending downwardly from said cover
plate, and at least one layer of a resilient compressible foam
sealant on each side of said spine.
[0011] In the present invention, the use of an impregnated foam
sealant as an elastic recovery or return force mechanism has the
dual advantage that the system can remain watertight immediately
below the level of the cover plate while at the same time the
impregnated foam sealant acts as the return force or stabilizing
element for the cover plate.
[0012] In an alternative embodiment of the present invention, a
waterproof membrane, eg. a bellow or pre-folded type of membrane is
provided below the cover plate, spanning the joint and running the
entire length of the joint. In this embodiment, the
resilient-impregnated foam may be discontinuous along the sides of
the central spine, whereby elastic recovery is achieved by means of
the resilient impregnated foam layers, by waterproofing is achieved
by the membrane above.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The above-mentioned and other features and advantages of
this invention, and the manner of attaining them, will become more
apparent and the invention will be better understood by reference
to the following description of an embodiment of the invention
taken in conjunction with the accompanying drawings, wherein:
[0014] FIG. 1 is a cross-sectional view of a prior art
seismic/expansion joint cover made by MIGUA;
[0015] FIG. 2 is a cross-sectional view of a prior art
seismic/expansion joint cover made by Watson Bowman;
[0016] FIG. 3 is a cross-sectional view of a first embodiment of
the present invention;
[0017] FIG. 4 is a cross-sectional view of a second embodiment of
the present invention;
[0018] FIG. 5 is cross-sectional view of a third embodiment of the
present invention;
[0019] FIG. 6 is a cross-sectional view of a fourth embodiment of
the present invention;
[0020] FIG. 7 is a cross-sectional view of a modified form of the
embodiment shown in FIG. 5;
[0021] FIG. 8 a cross-sectional view of another modified form of
the embodiment shown in FIG. 5;
[0022] FIG. 9 is a cross-sectional view of a further modified form
of the embodiment shown in FIG. 5;
[0023] FIG. 10 is a cross-sectional view of a modified form of the
embodiment shown in FIG. 6;
[0024] FIG. 11 is a cross-sectional view of a modification of the
invention, illustrated in connection with the FIG. 4 embodiment,
but applicable to the embodiments shown in FIGS. 4 to 10;
[0025] FIG. 12 is an end view of the membrane shown in FIG. 11;
and
[0026] FIGS. 13 and 14 are end view of clips for installing the
membrane of FIG. 12 in a joint.
[0027] Corresponding reference characters indicate corresponding
parts throughout the several views. The exemplification set out
herein illustrate preferred embodiments of the invention and such
exemplification is not to be construed as limiting the scope of the
invention in any manner.
DETAILED DESCRIPTION OF THE INVENTION
[0028] FIG. 3 illustrates the simplest form 1 of the present
invention. This essentially consists of a T-piece 2 that acts as
both the cover/slide plate and mechanism for self-centering of the
cover plate. The leg of the T extends into the joint. Its length is
dependent on joint dimensions and the size of the pre-compressed
expanding foam sealant 3 placed on either side of the leg. As can
be seen from FIG. 3, impregnated expanding foam sealant such as
20H.TM. System or GREYFLEX.TM. from Emseal Corporation is placed on
either side of the leg of the T.
[0029] Thus, the system is in equilibrium if the expansion force of
the impregnated expanding foam sealant to the left of the T is
equal or equivalent to that being exerted by the impregnated
expanding foam sealant to the right of the T. The system, such as,
can be considered "at rest". Should the joint experience an
extension due to a decrease in temperature or as a result of other
movements, the impregnated expanding foam sealant will have to fill
a greater void or distance between the faces of the joint. Due to
its expanding nature, it will do so in relation to the movement
experienced and thus come to a new "rest" position. In this new
rest position, forces to the left of the T will balance those to
the right of the T thus enabling the cover plate/slide plate to
remain centered over the joint.
[0030] However, the FIG. 3 configuration does not allow for an
inspection of the joint beneath the slide plate as the T section is
one solid piece. Therefore, provision must be made, as in FIG. 4
onwards, for the ability to remove the top cover plate/slide
assembly from that portion contained within the throat of the
joint. This is achieved as shown in FIG. 4. In addition, the
section contained in the joint may be provided with upper and lower
base flanges 5 (as shown) to position the impregnated expanding
foam sealant 3 more accurately and, in addition, enable the
vertical element 2 to be secured to the cover plate/slide plate
4.
[0031] FIG. 5 is an alternate embodiment that allows for the
removal of the cover plate/slide plate. This design allows for the
fact that irregularities in joint construction may exist in regard
to both the horizontal and vertical joint sizing parameters. In
other words, joint sides may not be perfectly parallel to one
another or equidistant from one another. The joint design criteria
may not be met during actual field construction of the joint. In
this case, the expansion of the impregnated expanding foam sealant
on the left side of the T piece may not be perfectly matched with
the expansion characteristics of the impregnated expanding foam
sealant on the right hand side of the T piece. This will be due to
joint irregularity, in width, vertical, and horizontal alignment,
occurring during the construction process. This situation should be
corrected to allow the cover plate/slide plate to remain (slide) in
contact with both opposing slabs that form the upper surface of the
joint. The configuration of FIG. 5 will allow, by tightening of the
respective screws 6, the ability to pull down the slide/cover plate
to the degree that is necessary and so enable it to rest on one or
other side of the joint in the correct manner.
[0032] The embodiment of FIG. 6 is an adaptation of that shown in
FIG. 5. However, in this case, the means to adjust the final
position of the cover plate/slide plate is moved to immediately
below the cover/slide plate.
[0033] It will be observed that the upper base flange in the
embodiment of FIG. 6 is incorporated in an angulated portion 7 that
is adjustable relative to the central spine 8 by means of
vertically extending slots in the spine and/or the angulated
portion, through which bolts 9 extend, which can be tightened after
the angulated portion is at the correct height. It will be
appreciated that in selecting the material from which the angulated
portion is to be fabricated, consideration should be given to
flexibility, since a joint may be somewhat uneven along its length.
Foam 3 is not shown in FIG. 6 for clarity of illustrating the other
elements.
[0034] Referring now to FIG. 7, modifications to enhance the water
resistance of the joint directly beneath the cover plate are
illustrated. The watertight properties of an impregnated expanding
foam sealant both to the left and right of the T piece may be
enhanced by the creation of a double seal at the upper surface
level of the impregnated expanding foam sealant closest to the
cover/slide plate. This may be achieved thorough the use of a low
modulus or ultra low modulus sealant 10 being applied to this
surface layer. The use of an ultra low modulus sealant (such as Dow
Corning 890 RTV Silicone Sealant) will provide the surface of the
impregnated expanding foam sealant 3 with a closed cell finish and
additional sealant layer which will reduce the depth requirement of
the impregnated expanding foam sealant beneath the low modulus
sealant. In addition, the use of the correctly chosen wet sealant
adhered to both the central spine and joint substrate will enhance
the elastic properties of the double seal configuration. In the
FIG. 7 configuration, the impregnated expanding foam sealant 3 will
act as the primary return force or memory, while the ultra low
modulus sealant will act as the primary watertight barrier, while
also enhancing the return force or memory of the composite seal. It
can be seen from this configuration that if this ultra low modulus
sealant is applied in a self-leveling format, after the impregnated
expanding foam sealant has been placed in the joint and allowed to
recover to joint size, that a watertight element is obtained in
terms of adhesion to the substrates.
[0035] The FIG. 7 installation is effected firstly by the
installation of the T piece with impregnated expanding foam sealant
applied to both sides of the T piece or central spine. This
assembly is adhered to the joint faces by means of a suitable
adhesive and allowed to recover from its pre-compressed delivery
and installation format. After recovery of the pre-compressed
impregnated expanding foam sealant, the ultra low modulus
self-leveling sealant (or other suitable sealant) is applied to the
top exposed surface of the impregnated expanding foam sealant on
either side of the central spine. Once the sealant has been
applied, a level may be applied across the top surface of the joint
to correctly align the brackets and cover plate/slide plate. The
cover/slide plate 4 is then screwed into position.
[0036] FIG. 8 shows a further modification and makes use of a
prepackaged product 11 consisting of layers of compressible and
non-compressible fam, with a sealant applied to the top surface
thereof, sold under the trade-mark COLORSEAL.TM., by Emseal
Corporation. In the case of the use of the Colorseal.TM. product, a
finishing of the detail will require that a corner or "heel" bead
be applied to effect the proper chemical termination and adhesion
of the top sealant to the substrate.
[0037] It can be seen from FIGS. 7 and 8 that the system can be
extended to utilized interleaving layers of impregnated expanding
foam sealant and closed cell foam or other resilient material to
assist in the recovery and stability of the composite structure
that is placed on either side of the central spine. In other words,
a composite matrix may be utilized as the return or recovery force
on either side of the central spine. The prime requirement is that
the material to be inserted into the joint is capable of being
pre-compressed and holding this pre-compression during the time
taken to install the material correctly into the joint. So, a
series of both differing densities of impregnated expanding foam
sealant and closed cell foam may be used to provide the recovery
force. This recovery force and composition of the structure will,
to a large extent, depend on the size (width) of joint to be formed
together with the performance characteristics required from the
joint (such as seismic or thermal movement characteristics,
etc.).
[0038] It will be observed from FIGS. 9 and 10 that further
combinations are possible. FIG. 9 illustrates a form of the present
invention utilizing a split central T-piece similar to that shown
in FIGS. 5 and 7, with a layered compressible and non-compressible
foam layers, available from Emseal Corporation under the trade-mark
BACKERSEAL.TM. 12 applied on each side of the T-piece, and a low
modulus wet sealant applied in the field on the top surface of
same, after it has expanded on each side to center the T-piece.
[0039] FIG. 10 illustrates a modification of the FIG. 6 form of the
invention, described in full above, but utilizing COLORSEAL.TM.
product 11 as a centering means on each side of the T.
[0040] The cover/slide plate construction may be chosen from the
metallic group of materials including stainless steel, bronze,
brass, aluminum, galvanized or plated steel, etc. The main
criterion for the choice of material is that allowable degree of
flexing that is undergone during the passage of vehicular or
pedestrian traffic while the material still retains its ability to
bridge the joint in the manner required by the design engineer. In
addition, the material should display corrosion-resistant
properties if used in an external environment. Thus, the larger the
joint that must be spanned by the cover/slide plate, the more rigid
the material. Conversely, as the gap to be spanned becomes
narrower, the distance between the joint faces is less and
alternate materials may be used, such as thermo-plastics or
thermo-plastics alloys (elastomers). The main criteria for the use
of such alloys are impact resistance, rigidity in load transfer,
and temperature resistance if exposed to an external environment.
It can thus also be seen that the cover/slide plate may be
constructed from composite materials such as fiber resins.
[0041] Thus, the final choice of material will depend on joint
width, load transfer, and structural integrity of the joint
assembly.
[0042] The sub-assembly beneath cover/slide plate may be chosen
from the group of metals including steel, aluminum, brass, and
bronze, which may be extruded or rolled to form the necessary
sections. The material should display corrosive-resistance
properties in accordance with the environment in which it will
operate (interior/exterior). However, the choice of material may
also include rigid plastics, thermo-plastic alloys, and
co-extrusions that are able to be fastened to the cover/slide plate
and provide the cover/slide plate with sufficient retention and
movement capability in relation to the movements being experienced
by the joint.
[0043] The preferable choice of material would be aluminum
extrusions.
[0044] Reference now is made to FIGS. 11 to 14, where an
alternative to using continuous length of resilient foam sealant on
each side of the central spine is illustrated.
[0045] It has been found that the equilibrium force necessary to
achieve equilibrium and thus create an "at rest" system, is in fact
smaller than the total force actually exerted by a continuous run
of impregnated expanding foam sealant (or the composite interleaved
structure) to the left and to the right of the spine. In other
words, the equilibrium of the system, and an "at rest" position,
may be achieved by a discontinuity of impregnated expanding foam
sealant (or the composite interleaved structure) to the left and to
the right of the spine. As such, the amount of impregnated
expanding foam sealant (or the composite interleaved structure) may
be reduced by as much as two-thirds, thus producing a substantial
cost-saving. The modification is that the application of, for
example, 250 mm long sections of impregnated expanding foam sealant
(or the composite interleaved structure) placed opposite one
another on either side of the spine may be followed by a further
section containing no material (void). This takes place in the
length of the joint. So, a section filled with impregnated
expanding foam sealant (or the composite interleaved structure) may
be followed by a section with no material at all. The distance
between sections will depend on the size of the joint, its vertical
or horizontal status, and whether it is being subjected to
vehicular, pedestrian, or other traffic. Ideally, the void section
would not be greater than twice the "sealed section". "Sealed"
sections will be about 0.3 to about 2.0 meters long.
[0046] However, it can be seen from the above that as a void
section has now been created on either side of the T and along the
line of sealant, that the second objective, "that the joint should
be watertight at, or immediately below, the line of waterproofing
that is applied to the deck", is not met.
[0047] In order to reinstate this objective, a "sealant line" is
achieved through a flexible waterproof membrane 13 attached to
either side of the joint face and placed immediately below the
cover plate assembly, as shown in FIG. 11.
[0048] The waterproof membrane 13 may be manufactured from flexible
plastic, rubber or neoprene, or thermo-plastic alloys (elastomers).
The waterproof membrane may be either in sheet form, looped
sufficiently in the joint to allow correct seismic or other
movement, or may be in the form of an extrusion or molding. The
example shown in FIGS. 11 and 12 is of an extrusion with
bellows-sections, allowing for the expected movements of the joint
for which it is intended. The thickness of material is variable, as
the membrane is subject to support, at intervals, by the staggered
sealant below. Thus, the thickness is ultimately determined by the
head of water that the entire system is expected to sustain. The
lower the head of water, the thinner the membrane may be. Ideally,
for an extruded section in a continuous length, the thickness of
material may be in the order of 1-5 mm. The range in thickness only
being subject to the conditions already described above and the
ease of handling of the extruded section on site and during
installation.
[0049] Two fixing methods or attachment methods, for attaching the
membrane to the substrate, are shown. However, the essence of the
modification is that the membrane would extend from one vertical
side of the joint to the other vertical side. Numerous attachment
methods are available as essentially the membrane will not be
exerting a tear strength along its line of attachment. The movement
of the membrane will be guided and assisted by the movement of the
T piece.
[0050] In FIG. 13, a clip 14 that attaches to a shallow squared
notch in the joint is shown (as further shown in FIG. 11). The clip
accepts the edges of the membrane 13, which may have barbs or other
thickenings formed in them for a tight fit. Additionally, an
adhesive bead may be applied into clip 14 before the edge of the
membrane is inserted. Clip 14 may be an extrusion of aluminum, or a
high density plastic, and may be grouted or adhesively attached to
the joint in a waterproof manner, along the length of the joint, on
both sides.
[0051] As shown in FIG. 14, a clip 15 may be provided that attaches
to the inside wall of the joint. This clip may be attached to the
joint wall by a fastener 15 such as a nail or screw, but should
also be sealed along the joint. Such a clip will also accept the
edge of the membrane, and is also a plastic or metal extrusion that
extends the length of the joint, along both sides thereof.
[0052] It is to be understood that the examples described above are
not meant to limit the scope of the present invention, it is
expected that the numerous variants will be obvious to one skilled
in the field of joint seal design without any departure from the
spirit of the invention. The intended claims, properly construed,
form the only limitation on the scope of the invention.
* * * * *