US3145503A

US3145503A - Joint water stop

Info

Publication number: US3145503A
Application number: US119926A
Authority: US
Inventors: Gordon L Brechin
Original assignee: Individual
Current assignee: Individual
Priority date: 1961-06-27
Filing date: 1961-06-27
Publication date: 1964-08-25
Anticipated expiration: 1981-08-25
Also published as: GB995451A; CH405383A; AT257487B

Description

Aug. 25, 1964 G. BRECHIN JOINT WATER STOP Filed June 27, 1961 CHIN mun/7w? GORDON L. BRE

United States Patent This invention relates to water stops for joints in pourable plastic materials, such as concrete.

It is often necessary to pour different parts or sections of concrete walls at different times, or to provide for the connection of a new wall to an old wall. In each case, the second or later pour of concrete is abutted against a surface of a previous pour. The new concrete contains a comparatively large volume of water, whereas the old concrete has set to a certain extent at least. As a result of this, the new concrete as it dries and sets shrinks relative to the old concrete, leaving a crack or space therebetween through which water can travel.

Water stops are employed in an effort to seal these joints in concrete in order to prevent water from passing therethrough. However, the water stops of the prior art are not completely satisfactory. One form of prior water stop consists of a fiat strip of elastic material which is partially embedded in the first pour of concrete, and projects outwardly from the end thereof. This necessitates a split form at the end of the form for the first pour in order to allow the strip to project outwardly therefrom. After the end form has been stripped away, the concrete for the second section is poured and is supposed to embed the projecting portion of the strip. When this happens, the strip is embedded in the old and new concrete, and most strips have anchoring means in the form of ribs and the like along the edges thereof so that they are anchored in the two wall sections. However, it quite often happens that the projecting portion of the rip is flattened and displaced from its proper position during the second pour of concrete, in which case it is not anchored in said second pour and failure results.

Another form of prior water stop comprises a strip of elastic material having staggered projections from opposite faces thereof that are embedded in the first and second pours of concrete. These projections have lateral ribs thereon to be sure they are anchored in their respective pours. With this construction, when the second pour shrinks relative to the first, the main body of the stop is pulled away from the first pour. In addition to this, the material forming the projections is elongated so that said projections get thinner and contract relative to the concrete in which they are embedded. Another disadvantage of this type of Water stop is that a part thereof is subjected to a shearing action since one face of said part is anchored to the oldconcrete and the opposite face thereof is anchored to the new.

The present water stop is so designed that it cannot be displaced either during the first or second pours of concrete at the joint where the water stop is employed.

A water stop according to the present invention avoids the above-noted disadvantages. It comprises a web strip having a pair of key legs extending longitudinally thereof and projecting outwardly from one of its faces. choring means is provided on and projects from the opposite face of said strip. In the preferred form of the invention, anchoring means is provided opposite each key leg. Said key legs are inclined towards each other to form a dovetail keyway therebetween. The anchoring means is adapted to be embedded in a first pour of concrete which covers the outer surfaces of the key legs. It is preferable, although not absolutely necessaryto provide a contractible core removably fitting in the keyway when the. first concrete is poured to prevent .collapseof said keyway. This core is moved after the initial setting of the first pour. When the second section of the wall is poured, some of the concrete flows into the keyway to form a dovetail key therein. When the second pour begins to contract, the dovetail key moves longitudinally of the wall in a direction away from the first pour. This tends to stretch the key legs which become thinner at this time, but the sides of the key are inclined and they are moving towards inclined portions of the first pour concrete to lessen the distance therebetween so that the key legs do not pull away from the concrete along the opposite surfaces thereof. In the preferred form of the invention, each key leg is unobstructed on its outer surface, and has ribs on its inner surface projecting into the keyway. Thus, the only portions (the key legs) of the water stop that can move when the second pour concrete contracts become more firmly gripped during the contracting action.

A preferred form of water stop is illustrated by way of example in the accompanying drawings, in which,

FIGURE 1 is a perspective view of the water stop,

FIGURE 2 is a cross section through the water stop after the first concrete has been poured with the end form or bulkhead still in place,

FIGURE 3 is a view similar to FIGURE 2, but with the end form or bulkhead removed and ready for the second pour, and

FIGURE 4 is a view similar to FIGURE 3 after the second concrete has been poured.

Referring to the drawings, If? is a preferred form of water stop which is formed of a suitable elastomeric material, such as rubber or polyvinyl chloride or other synthetic resin. The stop may be formed in any convenient manner, but it is usually extruded in the proper cross sectional shape so that it may be made any length and cut into pieces of desired lengths.

Water stop 10 includes a web strip 12 having

opposite faces

13 and 14. A pair of key legs 19 and 20 extend longitudinally of the strip and extend outwardly from face 14 thereof. These legs are preferably along the edges of the strip, as shown. Leg 19 has outer and

inner surfaces

22 and 23 which are substantially parallel. Although

leg surfaces

22 and 23 may be exactly parallel, it is preferable to have them converge a little in a direction away from strip 12 so that the leg is thinner at 25 near its outer edge than at 26 near its inner edge where it joins the web strip. Furthermore, it is preferable that the outer surface 22 be unobstructed or comparatively smooth, as shown, and that inner surface 23 be provided with one or more projections, such as a plurality of longitudinally-extending ribs 28, extending longitudinally thereof.

Key leg 20 is shaped in the same manner as leg 19. Leg 2%) has a smooth or unobstructed outer surface 30, and an inner surface 31 with a plurality of longitudinallyextending projections or ribs 32 extending outwardly therefrom towards ribs 28. Leg 20 may also be thinner at 35 near its outer edge than at 36 near its inner edge where it joins web 12.

Key legs 19 and 20 are inclined towards each other to form a dovetail keyway 39 therebetween. Although various angles of inclination may be used, it is preferable to incline each key leg from-3 to 7 .oif normalto web strip 12. In FIGURE 2, line 42 represents the general incline of leg 19 relative to the horizontal centre line 43 of web 12, while line 44 is normal to the latter centre'line. Angle 45 represents the angle of incline of the key leg relative to normal to the web strip.

It is preferable to provide

nailing flanges

48 and 49 along the outer edge of legs 19 and 20 and extending laterally therefrom.

Anchoring means is provided on webstr-ip 12 projecting from face 13 thereof. It is preferable to provide anchoring means opposite each of the key legs 19 and 20. In

this example, the anchoring means comprises laterally-- spaced

anchor legs

52 and 53 extending along strip 12 and projecting outwardly from face 13' thereof, said

legs

52 and 53 being respectively opposite key legs 19 and 29. Leg 52 is formed with inner and outer surfaces 55' and 56 which may be parallel, but'preferably diverge outwardly from strip 12, as shown.

Surfaces

55 and 56, are preferably formed with

projections

58 and 59 extending outwardly therefrom, said projections preferably being in the form of ribs extending longitudinally of their respective surfaces. Anchor leg 53 is shaped the same as leg 52, and preferably has longitudinally-extending

ribs

62 and 63 on its inner and outer surfaces, respectively.

The water stop It is substantially H-shaped in cross section, as clearly shown in FIGURES 2 to 4. When it is desired to make a concrete wall in two or more sections,

parallel forms

66 and 67 are erected for the wall, and an end form or bulkhead 63 is provided between these forms where the first pour of concrete is to end. Water stop is secured to a face of bulkhead 63 in the area where the first concrete is to be poured. The stop is usually nailed to the bulkhead, and it is preferable to use special nails 78 for this purpose, said nails being driven through

flanges

48 and 49 of the stop. Each nail has the usual head 71 on one end, and a special head 72 spaced from the first head. When a nail i0 is driven through one of the nailing flanges into the bulkhead, head 72 engages said flange while a portion of the nail and head 71 project away from the bulkhead, see FIGURE 2. Although not absolutely necessary, it is preferable to provide a contractible core 76 in keyway 39 between key legs 19 and 2%. Although any form of contractible core may be used, it is preferable to use a plurality of filler strips formed of rubber, plastic or other suitable material for this purpose. In this example, three filler strips 73, 79 and Bil are used. Each filler strip is wedge-shaped in cross section, see FIGURE 2, and they are alternately arranged side by side so that they fill keyway 39 of the water stop inside bulkhead 68. This contractible core prevents legs 19 and 2% from being pressed inwardly out of their proper positions when concrete is poured into

forms

66 and 67 around the stop. This first pour of concrete is indicated at 82. It will be noted that the first pour of concrete embeds anchor

legs

52 and 53, the ends of nails 74 and covers

outer surfaces

22 and 30 of key legs 19 and 2%.

After the first concrete 82 has set to some extent at least, bulkhead 68 is removed. During this operation, it is pulled away from nails 70 and the water stop, leaving core 76 exposed. This core is contracted and removed by first removing strip '79, after which strips 7 3 and 86 may be moved towards each other and then withdrawn from keyway 39. The water stop as shown in FIGURE 3 is now ready for the second pour.

The next concrete 85 is poured into

forms

66 and 67 and flows into keyway 39 to form a dovetail key 87 therein. This key is relatively large and projects well into the first pour concerete 82. As concrete 85 starts to dry and set, key 87 tends to move in the direction of arrows 89 and 90 in FIGURE 4. This key has sides 92 and 93 that are substantially parallel to surfaces 94 and 95, respectively, formed in the first concrete 82 by the outer surfaces of key legs 19 and 20. As the key moves in the direction of arrows 39 and 90, it tends to move legs 19 and 20 in the same direction owing to the dovetail shape of the key and to

ribs

28 and 32. As the outer surfaces 2?. and 30 of the key legs are smooth, said legs can move with the key without danger of shearing since they are not anchored to first pour concrete 82. Anchor

legs

52 and 53 are firmly anchored in concrete 82 so that they prevent strip 12 from being pulled away from said concrete during this action. This means that legs 19 and 26 are stretched as the second pour concrete contracts. How'- ever, the side surfaces 92 and 93 of key 87 are moving towards the surfaces 94 and 95 of the first pour concrete so that as the key legs get thinner, the spaces in which they are located also get thinner and therefore said legs are not pulled away from the concrete, In fact, as the contraction takes place, said key legs are more firmly gripped by the concrete. Thus, the contraction of the second pour concrete does not result in any portion of the water stop being pulled away from or otherwise separated from the surrounding concrete. At the same time, the portions of the water stop between the old and new concrete and not subjected to any shearing action.

As stated above, it is preferable that key legs 19 and 20 are inclined from 3 to 7 off normal to web strip 12. It has been found that 5 produces the best results. The reason for this is that if the incline is too little, the inclined side surfaces of the key do not move sufficiently towards the opposed inclined surfaces of the old concrete to maintain a tight grip on the key legs as the latter contract while they are being stretched. On the other hand, if the angle of incline is too great, the inclined sides of the key will compress the key legs until they become substantially solid, at which time there is danger of thd key breaking away from the main body of the second pour concrete. The use of the special nails 70 is desir able since said nails are firmly anchored in the first pour concrete at the time the bulkhead 68 is removed from the forms, and therefore, the water stop is not subjected to any strain at this time.

With reference now to the drawings and in view of the foregoing remarks, it is readily apparent that the key to forming a seal between the first and second pours is the angle of inclination of the surfaces of the key legs and the foregoing discussion of the general angle of inclination of the key legs themselves must be understood in this light. In the first place, the second pour of concrete must form a dovetail in the keyway provided because, if this were not so, the second pour would be free to pull away from the water stop. Therefore, the inner surface of each key leg, which forms the shape of the second pour dovetail, must form an acute angle of less than 90 with respect to web strip 12. Second, the outer surface of each key leg must be inclined at less than 90 with respect to the web strip because, if this were not so, irrespective of the shape of the dovetail, movement of the second pour would never cause compression of the water strip disposed between the pour thus defeating the whole purpose of the device-the provision of a stop compressed between the first and second pours. It is not, of course, necessary that the surfaces of the key legs be tapered as they may obviously be parallel without losing compression. However, each of those surfaces must be disposed at an angle of less than 90 with respect to the web strip. Specifically, the preferred angle of inclination is from 3 to 7 off normal or 83 to 87 with respect to web strip 12. Thus, where the key leg surfaces are parallel, each will be inclined within this preferred range. Where the legs are tapered slightly, although the general inclination of the key leg will remain at 83 to 87, the surfaces of the key legs may vary therefrom somewhat depending on the degree of taper utilized. 7

What I claim as my invention is:

1. A water stop for joints in pourable plastic materials such as concrete, comprising a web strip having first and second planar faces, a pair of laterally spaced anchor legs integral with said web strip and projecting outwardly from said first surface, a pair of key legs integral within said web strip and projecting outwardly from said second surface in substantial alignment with said anchor legs, said water stop being adapted to be imbedded in a first pour of plastic material such that the anchor legs, first web face and outer surface of said key legs are covered with said firstpour, projecting means on each anchor'leg'to'am chor said legs in said first pour, each of said key legs having an outer surface disposed at an angle of less than with respect to said second web face and an inner surface disposed at an angle of less than 90 with respect to said second Web face to form a dovetail keyway between said key legs adapted to receive a portion of a second pour of plastic material such that a formed dovetail of said second pour material is disposed within said keyway, projections on the inner surface of each key leg to anchor said inner surface to said second pour material, and said outer surface being smooth and free of projections opp0 site said projections whereby on relative movement of said second pour away from said first pour, each key leg remains disposed between said first and second pours with the inner surface of said key leg anchored to said second pour through said projections and with the outer surface free to move relative to said first pour due to the absence of projections on said outer surface.

2. A water stop for joints as claimed in claim 1 wherein the inner surface of said key legs is inclined relative to said outer surface such that the key legs are tapered to 6 be thinner at the outer ends thereof remote from said second web face.

3. A water stop for joints as claimed in claim 1 wherein the key legs are each provided with nailing flanges at the ends of the outer surfaces remote from said second Web face.

4. A water stop for joints as claimed in claim 1 comprising one pair only of said anchor legs and key legs.

5. A water stop for joints as claimed in claim 1 wherein the inner and outer surfaces of each key legs are inclined at about 83 to 87 with respect to the web strip.

References Cited in the file of this patent UNITED STATES PATENTS 2,798,373 Harza July 9, 1957 2,937,065 Harza May 17, 1960 FOREIGN PATENTS 799,426 France Apr. 4, 1936 861,251 Great Britain Feb. 15, 1961

Claims

1. A WATER STOP FOR JOINTS IN POURABLE PLASTIC MATERIALS SUCH AS CONCRETE, COMPRISING A WEB STRIP HAVING FIRST AND SECOND PLANAR FACES, A PAIR OF LATERALLY SPACED ANCHOR LEGS INTEGRAL WITH SAID WEB STRIP AND PROJECTING OUTWARDLY FROM SAID FIRST SURFACE, A PAIR OF KEY LEGS INTEGRAL WITHIN SAID WEB STRIP AND PROJECTING OUTWARDLY FROM SAID SECOND SURFACE IN SUBSTANTIAL ALIGNMENT WITH SAID ANCHOR LEGS, SAID WATER STOP BEING ADAPTED TO BE IMBEDDED IN A FIRST POUR OF PLASTIC MATERIAL SUCH THAT THE ANCHOR LEGS, FIRST WEB FACE AND OUTER SURFACE OF SAID KEY LEGS ARE COVERED WITH SAID FIRST POUR, PROJECTING MEANS ON EACH ANCHOR LEG TO ANCHOR SAID LEGS IN SAID FIRST POUR, EACH OF SAID KEY LEGS HAVING AN OUTER SURFACE DISPOSED AT AN ANGLE OF LESS THAN 90* WITH RESPECT TO SAID SECOND WEB FACE AND AN INNER SURFACE DISPOSED AT AN ANGLE OF LESS THAN 90* WITH RESPECT TO SAID SECOND WEB FACE TO FORM A DOVETAIL KEYWAY BETWEEN SAID KEY LEGS ADAPTED TO RECEIVE A PORTION OF A SECOND POUR OF PLASTIC MATERIAL SUCH THAT A FORMED DOVETAIL OF SAID SECOND POUR MATERIAL IS DISPOSED WITHIN SAID KEYWAY, PROJECTIONS ON THE INNER SURFACE OF EACH KEY LEGS TO ANCHOR SAID INNER SURFACE TO SAID SECOND POUR MATERIAL, AND SAID OUTER SURFACE BEING SMOOTH AND FREE OF PROJECTIONS OPPOSITE SAID PROJECTIONS WHEREBY ON RELATIVE MOVEMENT OF SAID SECOND POUR AWAY FROM SAID FIRST POUR, EACH KEY LEG REMAINS DISPOSED BETWEEN SAID FIRST AND SECOND POURS WITH THE INNER SURFACE OF SAID KEY LEG ANCHORED TO SAID SECOND POUR THROUGH SAID PROJECTIONS AND WITH THE OUTER SURFACE FREE TO MOVE RELATIVE TO SAID FIRST POUR DUE TO THE ABSENCE OF PROJECTIONS ON SAID OUTER SURFACE.