Waterstop with dynamic-sealing hydrophilic thermoplastic expansible soft flanges

Abstract

A waterstop assembly for use as embedded components in at least a pair of adjacent concrete slabs, defining elongated first and second waterstop panels including a main body sheet to which is mounted by coextrusion or insertion to both of its opposite top and bottom ends a soft expansible flange made from hydrophilic thermoplastic material. Each hydrophilic soft flange has such an expansion capability as to provide strong radially outward pressure applied by the soft flange against the adjacent concrete slabs, thus providing watertight interconnection therebetween. A welding block is taken in sandwich between overlapping transitional end portions of the first and second waterstop panels. Integral ridge and groove connectors interconnect the welding block with the waterstop panels. Resistance wires connected at one end to an electric power source fuse the welding block and the first and second waterstop panels, wherein a watertight joint is formed therebetween. An upright steel post is mounted spacedly parallel to a corresponding one of first and second waterstop panels, and a transverse anchor arm transversely spacedly retaining waterstop panel in upright operational condition parallel to the steel post before and during first concrete pour.

Claims

1. A waterstop assembly for use as an embedded component in at least a pair of adjacent concrete slabs for structures withstanding hydrostatic pressures, said waterstop assembly defining elongated first and second waterstop panels including a main thermoplastic body sheet to which is mounted by co-extrusion to both of its opposite top and bottom ends a soft expansible flange made from hydrophilic thermoplastic material; each hydrophilic soft flange having such an expansion capability responsive to water leakage engagement as to provide strong radially outward pressure applied by the soft flange against adjacent surfaces of the adjacent concrete slabs, thus providing watertight interconnection therebetween; and further including a welding block, interlock means releasably taking in sandwich and interlocking said welding block in between overlapping transitional end portions of said first and second waterstop panels, and welding means fusing said welding block and said first and second waterstop panels whereby a watertight joint is formed therewith.

2. A waterstop assembly as in claim 1, wherein said welding means includes a pair of high resistivity resistance wires, operatively connected at one end thereof to said welding block and coupled at opposite end thereof to a remotely located electrical power source, the electrical output of said power source sufficient for generating heat level such as to achieve structural material fusion of said welding block with said first and second waterstop panels so that said welding block and waterstop panels become as one.

3. A waterstop assembly as in claim 2, wherein said heat level at said welding block from said power source electrical output and high resistivity resistance wire is about 380° F. (193° C.).

4. A waterstop assembly as in claim 1, wherein each of said waterstop panels and said welding block include first and second opposite faces, and wherein said interlock means consists of ridge members, integral to said water stop panels opposite faces, and groove members, integral with said welding block opposite faces.

5. A waterstop assembly as in claim 4, wherein said ridge members consist of a number of lengthwisely extending and widthwisely spaced cross-sectionally T-shape ridges projecting from each of said waterstop panels opposite faces, and wherein said groove members consist of a number of cross-sectionally T-shape grooves made along said welding block opposite faces with said grooves sized and shaped complementarily to said T-shape ridges for sliding removable interlock of said welding blocks first face grooves with said waterstop panels first face ridges.

6. A waterstop assembly as in claim 5, further including a lengthwisely extending centerbulb made along an intermediate section of each said waterstop panels in between a pair of opposite said T-shape ridges thereof.

7. A waterstop assembly as in claim 5, further including a steel post, mounted upright in spacedly parallel fashion to at least one of said first and second waterstop panels, a transverse anchor arm transversely spacedly retaining said at least one waterstop panel in upright operational condition parallel to said steel post before and during first concrete pour, said anchor arm including a main leg, carrying at one end thereof a resilient C-shape clip and at its opposite end an arcuate clamp; said clip sized and shaped to snugly transversely engage and interlock in friction fit fashion with said steel post, while said arcuate clamp is sized and shaped to retainingly engage with a transversely registering cross-sectionally T-shape upper said ridge.

8. A waterstop assembly as in claim 7, further including a hinged cover mounted to said clamp for pivotal motion from an open inoperative clamp condition to a closed operative condition locking in place said clamp.

9. A waterstop assembly as in claim 1, wherein said welding block further includes a pair of integral lips projecting edgewisely outwardly from opposite ends thereof and extending parallel to said grooves, whereby still improved waterproofness is achieved at the level of said soft expansible flanges when said welding block is taken in sandwich between corresponding pair of said waterstop panels.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a perspective view of a pair of elongated waterstop thermoplastic extrusion panels with hydrophilic flanges according to one embodiment of the invention, these panels having a generally rectangular shape and showing a pair of expansible soft flanges anchored at opposite ends thereof and edgewisely interconnected by a welding block of similar width but shorter length and taken in sandwich between overlapping edgewise portions of the two thermoplastic extrusion panels, and further showing an autonomous power source battery operatively connected to the welding block by a pair of heat-generating resistance coil wires;

(2) FIG. 2 is an exploded view of the components of FIG. 1, but with the battery and resistance wires removed for clarity of the view, and separately showing the welding block to be sandwiched between edgewise portions of the pair of edgewisely overlapping waterstop extrusion panels as shown in FIG. 1;

(3) FIG. 3 is a plan view of one extrusion panel from FIG. 1, and further showing an upright steel bar extending spacedly parallel thereto;

(4) FIG. 3A is a cross-sectional view along line 3A-3A of FIG. 3, and further showing a foundation concrete slab from a first concrete pour into which are embedded the lower portion of the extrusion panel and of the upright steel bar, and also showing a hook arm transversely spacedly interlocking an upper portion of the extrusion panel with the upright steel bar, the combined said hook arm and upright steel bar providing support in upright condition of the waterstop panels during first concrete pouring;

(5) FIG. 4 is an exploded view at a smaller scale of the components of FIG. 3A, but with the concrete slab removed for clarity of the view;

(6) FIG. 5 is a perspective view at a smaller scale of the components of FIG. 3A;

(7) FIG. 6 is a plan view of an extrusion panel according to the embodiment of the invention, with adjacent associated pair of split formwork concrete slabs;

(8) FIGS. 6A and 6B are enlarged cross-sectional views taken along lines 6A/6B-6A/6B of FIG. 6, sequentially suggesting the effect of hydrostatic pressure induced water seepage along the gap between the pair of adjacent split formwork concrete slabs, and also suggesting how the hydrophilic flanges provide waterproofness for the concrete slab/waterstop interface;

(9) FIGS. 7 and 8 are enlarged cross-sectional views of the hydrophilic waterstop at the gap interface between the pair of adjacent concrete slabs, sequentially suggesting center bulb dynamic bulb deformation responsive to concrete slabs displacement loads relative to one another; and

(10) FIGS. 9 and 10 are sequential views similar to FIGS. 7 and 8 but showing alternate dynamic bulb deformation and associated transverse movement and lateral movement thereof.

DETAILED DESCRIPTION OF THE DRAWINGS

(11) In the embodiment of waterstop assembly 20 shown in FIGS. 1-2, there is provided a pair of elongated rectangular waterstop panels 22, 24, and a welding block 25 as wide as but shorter in length than panels 22 and 24. Each waterstop panel 22, 24, defines a number (e.g. four as shown) of pairs of lengthwisely extending transversely spaced cross-sectionally T-shape semi-rigid ridges or anchor elements 26, 26′ and 27, 27′, respectively on opposite faces thereof, and two opposite cross-sectionally C-shape rails 28, 30, and 29, 31, respectively, and expansible hydrophilic top and botton (widthwise) flexible soft flanges 32, 34 and 36, 38, respectively embedded inside said rails 28, 30, and 29, 31. Each soft flange 32-38 has an interior portion 32A, 34A, 36A and 38A, respectively anchored in friction-fit fashion inside the enclosures 28A, 30A, of rails 28, 30, respectively, and an exterior exposed portion 32B, 34B, 36B, 38B, respectively projecting outwardly from rails 28, 30, 29 and 31. Soft flanges 32-38 form co-extruded hydrophilic inserts within the open enclosures of rails 28, 30, and 29, 31, respectively.

(12) Separate welding block 25 includes a number of pairs of cross-sectionally T-shape lengthwise grooves 50, 50′, . . . on opposite faces thereof, numbered, sized and shaped for complementary removable sliding engagement by corresponding cross-sectionally T-shape ridges 26, 26′, . . . and 27, 27′, . . . of waterstop panels 22, 24. Accordingly, the two panels 22, 24 and the block 25 shown detached from one another in FIG. 2 can be releasably slidingly interlocked with cross-sectionally T-shape ridges 26, 26′, . . . and 27, 27′, . . . engaging grooves 50, 50′, . . . in end to end portions joint overlapping fashion as illustrated in FIG. 1.

(13) A pair of heat-generating resistance wires 40, 42, are connected at one end thereof to opposite end portions of welding block 25, and to their opposite ends to the anode 44 and cathode 46 of a remotely located electrical battery 48. Each resistance wire 40, 42, has a high coefficient of resistivity and high resistance to oxidation, leading to optimal heat generation. In one embodiment, wires 40, 42, are made from a non-magnetic 80/20 alloy of Nickel and Chromium. Wires 40, 42, may be wound into coils, for improved performance. Wires, 40, 42 may have for example a resistivity of 110×10.sup.−6 ohm-cm. The structural material of block 25 will be such, upon powered up by electrical battery 48, as to enable heat fusing of both overlapping end portions of waterstop panels 22, 24 including T-shape ridges 26, 26′, 27, 27′, . . . within grooves 50, 50′, so that the overlapped end portions of panels 22, 24, become one with welding block 25 in watertight fashion. In one embodiment, block 25 is made of PVC plastic. In one embodiment, fusion temperature generated by resistance coil wires 40, 42, will be about 380° F. (193.3° Celsius).

(14) Electric power sources other than battery 48 are not excluded from the scope of the present invention.

(15) FIGS. 3A and 5 show how the lower portion of upright waterstop panel 22 is half-embedded into a concrete foundation slab S.

(16) To support waterstop panel 22 (24) in upright operational standing condition as shown in FIGS. 3A and 5, before and during first foundation concrete pour, an upright steel post B is mounted spacedly parallel to waterstop panel 22 (24). Diameter of post B may be e.g. 0.5 inch (1.26 cm). A transverse anchor arm 52 is provided that transversely spacedly retains waterstop panel 22 (24) in upright operational condition parallel to steel post B. Anchor arm 52 includes a main leg 54, carrying at one end thereof a resilient C-shape clip 56 and at its opposite end an arcuate clamp 58. C-shape clip 56 is sized and shaped to snugly transversely engage and interlock in friction fit fashion with steel post B, while arcuate clamp 58 is sized and shaped to retainingly engage with a transversely registering cross-sectionally T-shape upper ridge 26″ from panel 22 (24). A hinged cover 60 is further mounted to clamp 58 for pivotal motion from an open inoperative clamp condition shown in FIG. 4, to a closed operative condition (locking clamp 58 into place) shown in FIGS. 3A and 5.

(17) FIG. 6 shows an alternate way of using waterstop assembly 20 in split formwork setting, being half-embedded into the facing edge portions of two adjacent concrete slabs S and S′. FIGS. 1-2, 3A, 5, 6A-6B and 7-10 show that each waterstop panel 22, 24, includes a centerbulb 70, 72, respectively.

(18) FIGS. 6A-6B further suggest how a volume of liquid V can seep transversely through a first inner gap G1 between the inner facing edges of the inner (half) section of concrete slabs S and S′, along arrow R1, to eventually reach waterstop 24 (22). Such liquid leakage may then continue flowing transversely from arrow R1 along opposite liquid flow arrows R2 and R3 from centerbulb 72 (70) over waterstop panels 24 (22), toward hydrophilic soft flanges 36, 38 (32, 34). These hydrophilic flanges under contact with water will then responsively apply an expansion biasing pressure against the adjacent portions of concrete slabs S and S′, thus creating a watertight seal therebetween (FIG. 6B). This watertight seal prevents fluid flow from edgewisely seeping around flanges 32-38 and from reaching a second gap G2 between the facing edges of the outer section of concrete slabs S and S′. Accordingly, outer gap G2 will remain dry in all circumstances.

(19) In FIG. 6B, the hatched portion 80 between the two waterstop panels 22, 24, represents the free air volume therebetween, with this free air volume being sealed at opposite waterstop lengthwise ends by the fused welding block 25 in the background of hatched portion 80 and shown in FIG. 2 but absent from FIG. 6B.

(20) FIGS. 7-10 suggest deformation of centerbulb 70 (72) under concrete slabs load deformations at 70′ (FIG. 8) or 70″ (FIG. 10), so that the waterstop assembly act properly as an expansion joint during any structural slab motion, enabling retaining structural integrity thereof including waterproofness. The waterstop design includes ribs with a centerbulb, whose purpose is to prevent passage of liquid through the joint. Such ribbed centerbulb profile is for application to both expansion and contraction joints, and will accommodate transverse and lateral slab movements. The ribs provide good watertight slabs interlock. The centerbulb accommodates typical joint movement.

(21) As already discussed in the background of the invention section, a problem with prior art methods of edgewise sealing of adjacent waterstop panels is that this is done in situ with welding irons heat-welding the thermoplastic waterstops end to end. This type of end to end sealing method is often of poor quality and this constitutes the weak link in the waterstop assembly. This is because the working environment is challenging to the worker, and also the worker needs to be skilled in his art to be able to perform adequately the end to end thermoplastic panels sealing. Prior art waterstop overlapping at intersection end portions is to be completely avoided under skilled workers best practices, i.e. clearly teaches away from waterstop end portions overlapping. On the contrary, with the present completely unobvious waterstop system, waterstop end to end portion overlapping is promoted rather than eschewed, and an unskilled worker can easily perform the sealing operation as well as a skilled worker, since the manual operation of applying welding irons to the waterstop panels edge portions is replaced by an automatic welding operation with resistance coil wires 40, 42, connected to electrical battery 48 and coupled to a welding block 25 fixedly sandwiched between two edgewise overlapping end portions of the waterstop panels 22, 24.

(22) In one embodiment as shown in FIG. 2, welding block 25 further includes a pair of integral lips 82, 84, projecting edgewisely outwardly from opposite ends thereof and extending parallel to block grooves 50, 50′, . . . . Lips 82, 84 provide still improved waterproofness at the level of meeting soft flanges 32, 36 or 34, 38 when welding block 25 is taken in sandwich between corresponding pair of waterstop panels 22, 24.

(23) Under experimental tests performed by applicant, the present waterstop has been found to be effective in fully resisting pressure equivalent to 250 feet (76.2 meters) of water column pressure, that is at a pressure level significantly higher than prior art waterstop. The present waterstop is easy to install by an unskilled worker, will resist accidental dislodgment during concrete pouring, will boast high elasticity and tensile strength, and is corrosion resistant in that its thermoplastic structural material is unaffected by acids, alkali, salts or other chemicals. The hydrophilic soft flanges at the lengthwise edges of the the present waterstop are swellable up to 400%. Each waterstop panel 22, 24, may have e.g. several meters in length, and may be flexible so as to be shipped in rolls.

(24) The welding battery 48 may be of low (e.g. 12 volts) voltage, such as a car battery, or alternately could be of high (e.g. 110 volts) voltage. Other power sources are not excluded from scope of the present invention.