Note: Descriptions are shown in the official language in which they were submitted.
HIGHWAY EXPANSION JOINT STRIP SEAL
BACK~ROUND OF THE INVENTION
Field of the Invention
This invention relates to a sealing structure for use
between spaced apart ends of adjacent concrete sections of
a highway, or adjacent sections of a bridge, to sealingly
accommodate changes in the spacing between the sections as
the result of thermal contractlon and expansion.
Description of the Prior Art
U.S. Patent No. ~,290,713 (D. D. Brown et al)
discloses a highway expansion joint strip seal in which
each of the opposed ends of an elastomeric strip is
provided with a do~nwardly extending enlargement or bead
which is engaged in an upwardly facing opening of a
metallic frame. Each metallic frame for use in such strip
seal is fabricated by roll forming, that is, from a flat
plate by rolling operations, which is a relatively
expensive manufacturing procedure. Elastomeric strips of
the type illustrated in this patent have also been used in
conjunction with metallic frames which are formed by
extrusion, also an expensive manufacturing procedure. U.S.
Patent ~o. 3r99~ 609 (G. S. Puccio) discloses a highway
expansion joint strip seal in which each of the opposed
ends of an elastomeric strip i5 provided with an enlarged
bead portion with an outwardly facing convex curved end
which is received in a generally C-shaped cavity of a
metallic edge member. The edge members of this reference
are manufactured by extrusion. Further, expansion joint
strip seals according to the prior art have been difficult
to assemble due to the need to insert the enlarged ends of
the elastomeric strip into the somewhat smaller opening of
metallic frame of edge members. To the extent that the
difficulty of assembly has been reduced by increasing the
size of the openings in the metallic frame or edge members
or by reducing the size of the enlarged ends of the
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elastomeric strip, the resistance of the elastomeric member
to being pulled out of the metallic frame or edge member
has been undesirably reduced.
SUMMARY OF THE INVENTION
According to the present invention there is provided
an expansion joint strip seal for a highway or a bridge
which is made up of a collapsible elastomeric membrane
whose opposed ends are provided with enlarged ear portions,
and a pair of spaced apart, opposed metallic frame or rail
members each of which is embedded at an edge of a concrete
highway or bridge section and each of which sealingly
engages one of the opposed ends of the elastomeric strip.
The elastomeric membrane is made up of an elongate,
generally horizontally extending web portion, which is
generally V-shaped in cross-section to provide the needed
flexibility for movement of the opposed ends toward and
away from each other, and a pair of enlarged, generally
vertically extending ear portions which are integrally
joined to opposed ends of the web portion at locations of
the ear portions which are closer to the bottoms thereof
than to the tops. Each of the ear portions is provided
with a pair of spaced apart internal voids which facilitate
the compression and distortion of the ear portion that is
needed to insert it into a generally C-shaped cavity of the
metallic rail member which receives such ear portion, and
the eccentric positioning of each ear portion with respect
to the web portion serves to provide a turning moment on
the ear portion when the web portion is under tension, to
thereby twist the ear portion within the cavity of the rail
member in which it is engaged and thereby increase the
pullout resistance of the ear portion. Further, the
configuration of the membrane is such that it is feasible
to produce suitable metallic frame or rail members to
sealingly receive ear portions at the opposed edges o~ the
membrane by a rolling procedure, at a substantial reduction
in the manufacturing costs o~ such frame or rail members.
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Accordingly, it is an object of the present invention
to provide an improved expansion joint strip seal~ It is a
further object of the present invention to provide an
improved highway expansion joint strip seal. More
particularly, it is an object of the present invention to
provide a highway expansion joint strip seal with reduced
assembly difficulty between an elastomeric membrane and
metallic frame members which sealingly engage opposed ends
of the elastomeric membrane, and with improved pullout
resistance between the elastomeric membrane and the
metallic frame members. It is also an object of the
present invention to provide an expansion joint strip seal
in which an elastomeric membrane component thereof is of a
configuration which permits the use of machined hot rolled
metallic frame or rail members to sealingly engage enlarged
ear portions at opposed edges of such membrane. It is also
an object of the present invention to provide an improved
elastomeric membrane for use in an expansion joint strip
seal. For a further understanding of the present invention
and the objects thereof, attention is directed to the
drawing and the following description thereof, to the
detailed description of the preferred embodiment and to the
appended claims.
BRIEF DESCRIPTION OF THE DRAWING
Fig. l is a ~ragmentary cross-sectional view of a
joint between adjacent sections of a highway, the joint
being provided with a strip seal according to a preferred
embodiment of the present invention;
Fig. 2 is a cross-sectional view of the elastomeric
membrane element of the strip seal illustrated in Fig. l;
and
Fig. 3 is a fragmentary, perspective view of a section
of a highway, including curbs, which incorporates a strip
seal of the type illustrated in Fig. l.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
_
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As is illustrated in Eig. 1, a typical highway
includ~s multiple concrete sections, such as sections 10
and 12, whose adjacent ends lOa and 12a, respectively, are
spaced apart from one another to accommodate thermal
expansion and contraction of the sections 10 and 12 due to
temperature changes. A strip seal, indicated generally at
14, is inserted between the ends lOa and 12a of the
sections 10 and 12 to prevent moisture, dirt and other
debris from filling the space between the ends lOa and 12a,
and possibly wedging thereunder, with resulting damage to
or deterioration of the sections 10 and 12. Of course, it
is to be understood that the strip seal 14 may be used to
provide for expansion and contraction between adjacent ends
of other planar structures, for example, bridge sections~
The strip seal 14 is made up of generally C-shaped
elongate metallic rails 16 and 18, and an elongate
elastomeric membrane 20 which extends between the metallic
rails 16 and 18. The metallic rails 16 and 18 are embedded
in the concrete sections 10 and 12, respectively, and
various types of anchoring devices, not shown, may be
attached to ~he metallic rails 16 and 18 to assist in
securely retaining them in the concrete sections 10 and 12.
The use of such anchoring devices in connection with the
anchoring of the metallic rails of a prior art highway
strip seal in concrete highway sections is known in the
prior art. See, for example, the aforesaid U.S. Patent
4,290,713.
Each of the metallic rails 16 and 18 is provided with
a generally horizontally extending top flange, elements 22
and 24, respectively, a generally horizontally extending
bottom flange, elements 26 and 28~ respectively, and a
: generally vertically extending web, elements 32 and 34,
respectively. The web 32 of the metallic rail 16 extends
from the left hand end of the top flange 22 to the left
hand end of the bottom flange 26, to impart a generally
C-shaped configuration to the metallic rail 16 with an
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internal cavity 36 having a restricted opening 38 that
extends to the rightl and the web 34 of the metallic rail
18 extends from the right hand end of the top flange 24 -to
the right hand end of the bottom flange 28 to impart a
generally reverse, C-shaped configuration to the metallic
rail 18 with an internal cavity 4~ having a restricted
opening 44 that extends to the left. The top flanges 22
and 24 have downwardly depending portions 22a and 24a,
respectively, each of which ends in a horizontally
tO extending flat surface area, elements 22b and 24b,
respectively, and the bottom flanges 26 and 28 have
upwardly extending portions 26a and 28a, respectively, each
of which ends in a horizontally extending flat surface
area, elements 26b and 28b, respectively. Thus, the
opening 38 in the rail 16, which is the vertical spacing
between the surface 22b and the surface 26b, has less
vertical extent than the cavity 36 and is entirely spaced
between the upper and lower extremities thereof, elements
36a and 36b, respectively, which are semi-circular in
cross-sectional configuration, and the opening 44 in the
rail 18, which is the ver~ical spacing between the surface
24b and the surface 28b, has less vertical extent than the
cavity 42 and is entirely spaced between the upper and
lower extremities thereof, elements 42a and 42b
respectively, which are also semi-circular in
cross-sectional configuration. Each of the rails 16-and 18
may be manufactured in one piece from steel in the
illustrated, mirror image, complex configurations
relatively inexpensively by conventional hot rolling
techniques of the type utilized in steel mills in the
manufacture of I beams and other structural steel shapes,
subject, of course, to a need to machine the surfaces of
the cavities 36 and 42 in the rails 16 and 18,
respectively, including the surfaces of the openings 3B and
44, but nevertheless without the need to employ more
expensive manufacturing techniques such as extrusion or
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roll forming. Of course, it is to be understood that it is
also contemplated that the rails 16 and 18 may also be
manufactured by extrusion or roll forming, if the product
characteristics which result from either of such
manufacturing processes are desired.
The elongate elastomeric membrane 20 is formed
integrally in a single piece from a suitable elastomeric
material, for example polychloroprene with a Durometer A
hardness of approximately 60 + 5, and this may be done by
extrusion. The membrane 20 has a yenerally horizontally
extending web portion 52, which is generally V-shaped in
cross section, and generally vertically extending, mirror
image ear portions 54 and 56 which are attached to the
opposed ends of the web portion 52, the V-shape of the web
.15 portion 52 facilitating the changes in spacing between the
ear portions 54 and 56 to accornmodate changes in spacing
between the ends lOa and 12a of the hi~hway sections 10 and
12. The ear portion 54 has a free end 54a which is sized
and shaped to fit snugly within the cavity 36 of the rail
16, and a transitional portion 54b which is sized and
shaped, and positioned relative to the free end 54a, to
extend through and fit snugly within the opening 38 in the
rail 16. Likewise, the ear portion 56 has a free end 56a
which is sized and shaped to fit snugly within the cavity
42 of the rail 18, and a transitional portion 56b which is
sized and shaped,and positioned relative to the free end
56a, to fit snugly within the opening 44 in the rail 18.
Thus, the vertical extent of the free end 54a of the ear
portion 54 of the membrane 20 is greater than the vertical
extent of the opening 33 in the rail 16, and the free end
54a must be compressed in the vertical direction to permit
it to be inserted through the opening 38 into the cavity 36
of the rail 16. To facilitate the compressing of the free
end 54a of the ear portion 54, the free end 54a is provided
with spaced apart, horizontally elongate internal cavities
62 and 64. Similarly, the vertical extent of the free end
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56a of the ear portion 56 of the membrane 20 is greater
than the vertical extent of the opening 44 in the rail 18,
and the free end 54 is provided with spaced apart,
horizontally extending elongate internal cavities 66 and 68
to facilitate the vertical compressing of the free end 56a
to permit it to be inserted through the opening 44 into the
cavity 42 of the rail 18. The cavity 62 is spaced a given
distance from the top of the free end 54a of the ear 54 and
the cavity 64 is spaced a slightly greater distance from
the bottom of the free end 54a. Likewise, the cavity 66 is
spaced a given distance from the top of the free end 56a of
the ear 54 and the ca~ity 68 is spaced a slightly greater
distance from the bottom of the free end 56a.
Sealing contact between the ear portion 54 of the
elastomeric membrane 20 and the rail 16 primarily occurs at
the surfaces 22b and 26b of the rail 16, and to this end
the transitional portion 54b of the ear porti.on 54 is
provided with parallel, upper and lower surfaces 54c and
54d, respectively, which sealingly engage the surfaces 22b
and 26b, respectively, of the rail 16. Similarly, sealing
contact between the ear portion 56 of the elastomeric
membrane 20 and the rail 18 primarily occurs at the
surfaces 24b and 28b of the rail 18, and to this end the
transitional portion 56b of the ear portion is provided
with parallel, upper and lower surfaces 56c and 56d,
respectively, which sealingly engage the surfaces 24b and
28b, respectively, of the rail 18. To ensure proper
sealing engagement be.tween the transitional portion 54b of
the ear portion 54 and the opening 38 in the rail 16, and
proper sealing engagement between the transitional portion
56b of the ear portion 56 and the opening 44 in the rail
18, the relaxed or uncompressed spacing between the
surfaces 54c and 54d must exceed the spacing between the
surfaces 22b and 26b, and the relaxed or uncompressed
spacing between the surfaces 56c and 56d must exceed the
spacing between the 24b and 28b. For example, it has been
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found that good, water tight sealing can be obtained in a
strip seal 14 of the type described when the relaxed or
uncompressed spacing between the surfaces 54c and 54d,
which is equal to that between the surfaces 56c and 58d, is
0.860 in., and with a spacing between the surfaces 22b and
26b, which is equal to that between the surfaces 24b and
28b, of 0.813 in..
~ s is clear from a comparison of Fig. 2 and Fig. 1, in
the relaxed condition of the elastomeric membrane 20, as is
shown in Fig. 2, the ear portions 54 and 56 extend
obliquely with respect to the horizon whereas in the
assembled condition of the membrane 20 the ear portions
extend vertically. Thus, a twisting movement is imparted
to the ear portions 54 and 56 by the rails 16 and 18,
respectively, which tènds to increase the interference fit
between the ear portions 54 and 56 and the openings 38 and
44, respectively, and thereby increase the resistance of
the elastomeric membrane 20 to being pulled out of the
rails 16 and 18 u~der a tensile load, for example, in
exceptionally cold weather when the spacing between the
ends lOa and 12a of the high~ay sections is large.
Further, twisting of the ears 54 and 56 within the rails 16
and 18, respectively, under tensile load, is increased by
positioning the junctures between the web portion 52 and
the ear portions 54 and 56 eccentrically between the top
and bottom of each such ear portion, preferably in
alignment with the lower voids 64 and 68, respectively, and
this further increases the resistance of the elastomeric
member 20 to being pulled out of the rails 16 and 18 under
a tensile load.
The use of voids 62 and 64 in the ear 54 of the
elastomeric membrane 20, and the use of voids 66 and 68 in
the ear 56 makes it possible to obtain fairly sharp upturns
in the strip seal 14, for example, even 90 upturns. Thus,
as is shown in Fig. 3, the strip seal 14 may be employed in
a highway having sections 10 and 12 which have curbs lOb
5~
and lOc, and 12b and 12c, respectively, along the opposed
edges thereo~.
Although the best mode contemplated by the inventor
for carrying out the present invention as of the filing
date hereof has been shown and described herein, it will be
apparent to those skilled in the art that suitable
modifications, variations, and equivalents may be made
without departing from the scope of the invention, such
scope being limited solely by the terms of the following
claims.
