Background of the Invention
The present invention relates to an improved expansion joint sealing element or, more specifically, to specially developed technical and functional improvements taking into account the characteristics of an ideal expansion joint sealing element, suitable for use in different situations, primarily when significant movements and considerable hydraulic pressure are involved, as is generally the case in dams.
As those familiar with this technology already know, the importance of the sealing element in the expansion joints used in public works construction has been widely recognized for many years. It becomes even more important as the stress on it increases, especially when subjected to significant movements and hydraulic pressure, as is generally the case in dams.
At present, three different types of sealing elements are regularly used in dams: strips of copper, strips of PVC and mastics between elastomer sheets. Although the above noted sealing elements can be used in expansion joints, they are subject to certain limitations or disadvantages, such as: A) strips of PVC, positioned during the laying of the concrete and affixed to the frame, are not elastic and, consequently, do not retain their shape and position when subjected to deformations; B) mastic protected by elastomer sheets, when subjected to high pressure, leak out if a seam breaks; and C) the sheets are generally affixed by means of metal angle plates and anchor bolts, which can rust.
Given the above circumstances and disadvantages and with a view to overcoming them, the present invention was created, which consists essentially of a non-metal sealing element affixed by means of a strong polymer adhesive and made of a high quality elastomer, especially as regards its resistance to weather, alkalis, molds, mildew, oil, grease, etc.
Objects and Brief Summary of the Invention
An advantageous factor of the present invention is the cross section of the device since, unlike conventional joint sealing element, it is in the form of an elastomer strip with a unique arrow shape, which is hollow or which has hollow sections that form longitudinal chambers. The novel external configuration of the expansion joint sealing element consists of a triangular head and a rear section that can be inserted into a joint wherein the joint is entirely covered by the element head. The rear section of the element is preferably provided with ridges or uneven surfaces (viz. corrugations) that adapt to the inner walls of the joint and to the exterior walls that are adjacent to the joint.
Yet another advantage of the expansion joint sealing element of the present invention is the fact that the size of the extruded elastomer strip is perfectly suited to the expansion joint and the stresses on it, as well as the fact that it can be inserted in the expansion joint to be sealed either all at once or in consecutive stages.
Still another advantage of the expansion joint sealing element of the present invention is the existence of a valve, previously installed in the strip, the ends of which are closed, thereby permitting the injection of air into internal chambers of the strip. The presence of the corrugations considerably increase the area of adhesion such that when the air is injected, the walls of the elastomer strip, with exposed corrugations, press against the adhesive and prevent the strip from moving while the adhesive cures.
Still another advantage of the expansion joint sealing element of the present invention is the novel edge configuration of the strip, which form the base of the triangular head of the strip, whereby the edges are affixed to the concrete with a device that exerts mechanical pressure on it.
Drawings
Other objects and advantages of the present invention will become apparent from the following detailed description of a preferred embodiment thereof taken in conjunction with the accompanying drawings, wherein:
FIG. 1 is a cross-section, illustrating the shape of the elastomer strip;
FIG. 2 is a perspective view showing the end of the strip with a valve; and
FIG. 3 is a cross-section of the sealing element inserted in a joint.
Detailed Description
Referring now to the drawings and particularly to FIG. 1, an embodiment of the improved expansion sealing joint element is shown which includes an arrow-shaped elastomer strip (1) consisting of a triangular head (2) and a rear insertion section (3). The rear insertion section (3) occupies about a third of the cross-sectional width of the base (7) of the head (2) and the distal end (4) of the rear wall appears comprises two adjacent panels that form a wide angle like the two sides of a roof. Lateral walls (5) are externally corrugated or ridged (6), an arrangement that is also found on the external surface of the base (7) and the lateral sections of the head (2). The head (2), along with the insertion section (3), has various longitudinal hollow sections defined by various interior walls (8) which are positioned at different angles to one another and to the lateral walls of the strip, thus forming an actual chamber (9), also in the shape of an arrow, for inflation. One end of the strip (1) is closed off or appropriately sealed, while the other end is fitted with a cover (10) and a valve (11) (note FIG. 2).
With this arrangement, the strip (1) of the present invention may be inserted and positioned within a given joint, as illustrated in FIG. 3. Once positioned, air is pumped into the interior chamber of the strip (1), so that the walls of the elastomer strip press against the adhesive applied to the sides of the strip. The ridges (6) serve to considerably increase the area of adhesion and prevent the strip from moving while said adhesive cures.
A recess (R) in the concrete is provided in plan so that the strip remains confined within this space, and when hydraulic pressure is exerted, the strip (1) will encounter lateral resistance and will be deflected against its interior walls, thus preventing tractive stress on the concrete. It is well known that concrete has little tensile strength and is approximately 10 (ten) times more resistant to compression.
When hydraulic pressure is exerted, the strip is deformed and presses against the edges of the concrete, distributing the compressive forces and providing a better performance of the system. Moreover, the strip absorbs structural movements caused by traction, compression, shearing, uneven settling and rotation.
The instant expansion joint sealing element is an improvement over prior art arrangements and provides an increase in efficiency, an improvement in operational performance and is easier to use in application. In describing the invention, reference has been made to a preferred embodiment and illustrative advantages of the invention. Those skilled in the art, however, and familiar with the instant disclosure of the subject invention, may recognize additions, deletions, modifications, substitutions and other changes which fall within the purview of the subject invention.