Expansion and seismic joint covers
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.
1. Field of the Invention
The present invention relates to the field of seismic and expansion joint covers.
2. Description of the Related Art
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.
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.
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.
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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.
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.
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 DRAWINGSThe 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:
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
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.
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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.
Thus, the final choice of material will depend on joint width, load transfer, and structural integrity of the joint assembly.
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.
The preferable choice of material would be aluminum extrusions.
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.
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.
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.
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
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
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.
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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.
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.
Type: Application
Filed: May 6, 2004
Publication Date: Jan 13, 2005
Inventor: Konrad Baerveldt (Toronto)
Application Number: 10/841,176