POOL CONSTRUCTION

Abstract: A method and apparatus for construction of swim pools comprised of a plurality of wall panels (23) aligned at their bottom edges by brackets (13) and at their top edges by preformed coping members. The coping members have apertures to locate and retain a tensioning cable used to withstand outwardly directed forces on the wall members. The pool has a concrete base (30) and a vinyl membrane lining.

Description: POOL CONSTRUCTION The present invention relates to water containers and in particular, but not exclusively, to a pref bricated or semi-prefabricated swimming pool. There are basically two general forms of prefabri¬ cated swimming pool available, the rigid fibreglass pool, which is supported in an excavation, and the liner-type pool which commonly takes the form of an above-ground pool having upstanding peripheral walls lined with a waterproof liner and 10 supported by a frame. Such prefabricated pools are normally manufactured to a particular shape and this shape cannot be easily varied. In the case of prefabricated below-ground pools such as fibreglass pools, if variations are required, then different moulds have to be provided for each variation. I-*- As the produc-ion of such moulds is expensive, it is difficult for a manufacturer to provide a range of different shaped pools. Accordingly if a person requires a nor.-s-car-ca ά pool, then usually it would be custom made or alternatively the person may select a concrete pool which may be shaped to his - requirements, but of course both of these alternatives are more costly in comparison with standard prefabricated pools. Further, conventional liner-type pools require a substantial amount of buttressing to support the walls from collapsing inwardly due to ground pressure in the absence of 25 water in the pool or alternatively to expand outwardly when the pool is filled with water and particularly when the pool walls are fully or partly above ground level. Also as it is often desirable to keep the number of buttresses to a minimum in view of constructional costs; the pool walls between 30 buttresses are long in respect to their height and accordingly require strengthening and/or reinforcing to withstand the working pressures along their length. Thus the need for strong walls tends to preclude the use of lightweight and less costly materials in the construction of the pool. 35 It is an aim of the resent invention to provide a method and apparatus for the construction of a liquid retaining structure adaptable to a wide variety of shapes and sizes and which permits rapid and economical yet sturdy and durable construction while retaining an aestheticaliy pleasing appearance. According to one embodiment of the present invention there is provided an apparatus for constructing a liquid retaining structure ccmprising:- a plurality of wall panels adapted for edge to edge engagement; lower retaining means for retaining the lower edges of said panels in desired edge to edge alignment; and, a plurality of preformed coping members adapted re engage the upper edges of said wall panels to retain said wall panels in desired edge to edge alignment; said coping members adapted to supper- ter.sior-ir.g means adjacent the upper edge of said wall panels such that when said tensicning means is pensioned, said coping members act in compression to withstand inwardly directed forces on said wall panels and said tensicning means acts in tension to withstand outwardly directed forces on said wall panels. Preferably the wall panels comprise fibre reinforce; concrete and most preferably comprise FIΞRΞSTΞΞL (Regd. Trade Z'.ark) reinforced concrete. Preferably the lower retaining means comprises a channel sectioned member, most preferably of galvanized iron. Preferably the coping members are provided with an aperture to engage the upper edges of said wall panels and most preferably, the aperture is tapered inwardly to permit firm frictional engagement with the upper edges cf said panel: Preferably said wall members and said coping members are formed in a plurality of complementary lateral cross-sectional shapes including straight section, concave curves and convex curves to permit construction of liquid retaininσ structures selected from a wide varietv of ' perimetral shapes. Preferably one or more of said coping members includes a hollow aperture extending lengthwise thereof to support a tensioning means. Preferably the tensioning means comprises a steel cable arranged about an outer wall of said coping members adjacent the' upper edges of said wall panels and most preferably is retained in a desired position by brackets extending between adjacent edges of said coping members. According to another aspect of the invention there is provided a liquid retaining structure comprising:- a plurality of preformed wall panels arranged in edge to edge relationship to form a wall member of pre¬ determined shape on a base; said wall panels being maintained in a desired edge to edge relationship at their respective lower edges by lower retaining means and at their respective upper edges by a plurality of preformed coping members; tensioning means arranged about outwardly facing edges of said coping members adjacent the upper edges of said wall member to permit said coping members to act in compression to withstand inwardly directed forces on the wall member and said tensioning means to act under tension to withstand outwardly directed forces on the wall member. Preferably said liquid retaining structure is formed within a cavity in the ground and most preferably concrete is cast between the outer surface of the wall member and the cavity wall. Preferably the liquid retaining structure includes a concrete floor cast within the wall member. Preferably the floor is formed with a concave de¬ pression. Preferably the liquid retaining structure includes a liquid impervious membrane releasably retained by retaining means adjacent the upper part of the wall member. Preferably the structure includes means for evacuating the space between the membrane and the wall and floor members. Preferably the structure includes means for removal of liquid accumulated between the membrane and the wall member. In yet a further aspect of the invention, there is provided a method for the construction of a liquid retaining structure comprising:- arranging a plurality of preformed wall panels to form an essentially continuous wall member of predetermined perimetral shape; retaining the lower edges of said wall panels in desired edge to edge relationship with lower retaining means; retaining the upper edges of said wall panels in desired edge to edge relationship with coping members of complementary lateral cross-sectional shape; retainably positioning a tensioning means about outwardly facing walls of said coping members adjacent the upper edge of said wall panels; and, tensioning said tensioning means to permit said coping members, under compression, to withstand inwardly directed forces on said wall panels and said tensicning means, under tension, to withstand outwardly directed forces on said wall panels. Preferably said structure is formed within an excavation within a ground surface. Preferably concrete is cast around the external perimeter of said structure. Preferably a concrete floor is cast within the perimeter of said structure. Preferably said floor is formed with a concave depressio . Preferably a water impervious membrane is arranged within said structure and relεasablv retained therein bv a retaining means arranged adjacent the upper edge of said wall panels . Preferably the space between the membrane and the inner wall and floor of the structure is evacuated prior to filling with liquid. One particular embodiment of the invention will now be described with reference to the construction of in-ground swimming pools. In the accompanying drawings, FIG.l illustrates plar and vertical cross-sectional views of a series of coping memb¬ ers the shading patterns on the plan views being incorporated merely to distinguish the coping sections in FIGS. 12-19 as hereinafter described. FIG. 2 illustrates plan and vertical crcss- sectional views of wall panels; FIG. 3 illustrates a lower retaining member; FIG. 4 illustrates a cable support bracket; FIG. 5 illustrates a membrane retaining member; FIG. 6 illustrates the wall structure of a swimming pool under construction; FIG. 7 illustrates a partially completed pool structure; FIG. 8 illustrates the structure of a step out; FIG. 9 illustrates a completed, tiled step out; FIG. 10 illustrates an auxilliary membrane retain¬ ing member; FIG. 11 illustrates the construction of a spa unit; FIGS. 12-19 illustrate a number of pool shapes which may be constructed in accordance with the invention; FIGS. 20 and 21 illustrate alternative methods of finishing the upper surface of the coping sections. In FIG. 1 (enlarged) , coping section la is formed as a straight section from reinforced concrete. In cross section it is formed in essentially a "T" shape with face 1 formed essentially at a right angle to upper surface 2. The aperture 3 is formed with an outwardly sloping face 4 to permit close frictional engagement with a wall - 6 - panel Cnot shown!. Coping section lb is essentially identical to la except that the rear or outwardly facing portion is formed as a solid section without the recess shown in la. A hollow aperture 5 extends lengthwise of coping section lb to support a tensioning cable Cnot show 1. The position of the hollow- aperture 5 corresponds with the boundary of the two faces forming the recess in the rear of section la. Coping section lc is shaped to permit access to a conventional skimmer box and includes an access aperture 6 and a cut-away portion 7 defining the upper part of a skimmer box opening through a wall member. Coping sections Id, le, If and Ig illustrate a "fast" curve, a "slow" curve, a "spa" curve and an inverted "step out" curve, the purpose of which will be described later. FIG. 2 illustrates plan and vertical crcss-secticna views of various wall members from which it may be seen that the wall members are available as a standard height cr as fractional heights . FIG. 2a illustrates an enlarged view of the upper edge of a wall panel showing an inwardly facing rebate 11 for attachment of a membrane liner retaining member (not shown) . Adjacent the upper vertical edges of the wail panel are positioned holes 12 which permit the adjacent edges of wall panels to be temporarily held together with a wire tie. FIGS. 2c - 2g illustrate respectively a "fast" curve, a "slow" curve, an inverted "fast" curve, a "spa" curve and an inverted "step out" curve. FIG. 2h illustrates a wall section with skimmer box fitting attached. FIG. 3 illustrates a lower retaining member 13 for retaining the lower edges of the wall panels together in parallel face to face relationship. FIG. 4 illustrates a tensioning cable retaining bracket 14 comprising an upright leg .15 and a right angled flange 16 extending therefrom. A tensioning cable aperture 17 is provided in leg 15. FIG. 5 illustrates a membrane retaining member comprising extruded sections 18 and 19 of plastics material. Section 18 is adapted to Be affixed to a wall panel and a portion of membrane folded over upstanding leg 20 is releasably secured thereto by section 19. The construction of a swimming pool according to the invention will now be described with reference to FIG. 6. Having selected a suitable site, an excavation 21 of slightly larger dimensions than the required pool size is made in the ground. The floor of the pool is shaped as a smooth convex depression 22 within the perimeter of the excavation. The wall panels 23 are set vertically in the excavation, side by side, and are temporarily held together by wire twitches 24 through preformed holes 12 in the side edge portions of the panels. At each junction of succeeding panels, the two panels are supported on concrete blocks 25 and located in a galvanized iron base bracket 13 fitting loosely under the joint. One of the wall panels is formed, near to its top, with a rectangular aperture in which is fixed a skimmer extension throat, to enable a skimmer box and return fittings to be installed. With the wall panels installed and levelled as required with some pieces of, for example, fibro-cement between their bottoms and their supports, coping sections of corresponding curvature are set in place. The coping sections are arranged to overlap the edge joins of the wall panels and the inwardly tapered groove therein ensures accurate face to face location of the wall panels. Prior to positioning the coping sections, the upper and outer portions of the wall panels are coated with adhesive grout. The adhesive mixture is used also in vertical joints between coping pieces, and in each joing there is cemented a cable bracket 14 which may be of galvanized sheet steel with a top flange 16 hearing on one coping piece, the lower part of the bracket having a hole 15 located at the junction of the coping piece top and the outside face of the downward projection. A cable is passed about the coping pieces and through the apertures of the cable brackets and is tensioned by the use of a turnbuckle or the like. Certain coping pieces, including any that may be made with a reverse curve, convex when viewed from within the pool, are made with holes 5 through them from end to end to receive the cable, the cable brackets being omitted. FIG. 7 illustrates a partially completed pool in which a vacuum pipe is installed which may suitably include an elbow 24 with one end opening into the pool through a hois at or near the bottom of one wall panel, its other end connected to an upright pipe 25 to the outside of the panel, the top of this pipe being connected, through a further elbow 26, to one end of a discharge pipe 27 below the coping and inclining down towards its other end. The purpose of the vacuum pipe is to facilitate the positioning of the pool liner membrane and to allov/ for discharge of any water which may find its way between the liner and the pool interior. Water seeping inwardly via hydrostatic valve 28 from surrounding ground is forced up to the perimetral join between the pool wall and floor and is discharged by a siphon action via pipe 27. The hydrostatic valve simply comprises a tube 28 extending from a drainage pit 29 beneath the pool floor. A concrete bottom 30 is laid for the pool and is trowelled smooth, and concrete is also poured between the wall panels and the excavation. A liner retaining section 18 as illustrated in FIG. of any suitable material such as plastics is riveted to the upper inside parts of the wall panels, within the rebates - 9 - thereof, the section consisting of a flat upright section which is riveted adjacent its lower edge flat against the rebated section 11 of wall panels the upper edge being retained in the tapered aperture 3 of the coping section. A membrane liner, preferably vinyl, for the pool has its upper edge portion folded over a liner retaining strip 19. which is of inverted-channel form, the excess liner portion hanging down outside the main part of the liner wall. The retaining strip 19., with part of the liner wrapped about it, is hooked into engagement with the channel of the liner retaining extrusion, the overhang of the excess liner being adjusted to suit the pool and to ensure that the seam where the wall of the liner joins the liner bottom is correctly located. A particular advantage associated with this liner retention means is that not only does it firmly retain the liner edge in position by a self-locking action, but the retention means is readily reieasable to allow adjustment cf tension on the liner material e.g. to take up stretch or to reduce tension. A vacuum pump connected to the pipe 27 is used to withdraw air from between the liner and the pool bottom and sides before the pool is filled with water. A pool may be made with a step out section as illustrated in FIGS. 8 and 9. by using reduced height wall panels for one section of the lower part of the pool wall, and shallow wall panels, including panels reversed for inverted curves, above the level of this lower wall section, to result in a shallow outward extension of the pool structure, this outward extension being provided with a concrete floor and a coping. The vinyl liner has a part cut away at the opening to the step out section, the edge of the opening formed in the liner being secured to the pool wall panels with the auxilliary retaining member 30 illustrated in FIG. 10. The function of the auxilliary retaining member is similar to that of the main liner retaining member of - 10 - FIG. 5 in that it is riveted to the edge of the step cut opening through the lower channel 31 and the edge of the liner is retained in the upper channel 32 by forcing in¬ sert 33 and the liner thereinto. Excess liner material is then trimmed away and tiles and any appropriate sealing means are provided along the bottom and sides and the entry of the step out section to the main part of the cool as illustrated in FIG. 9. If required a spa may also be formed at the perimeter of the pool as shown in FIG. 11. A step out construction is formed as described above but an inner wall 34 is formed to isolate the spa from the pool. Naturally, the vinyl liner is not cut away at this region but continues around the inner wall of the pool. Instead of positioning a coping section on the upper part cf wall 34, it may be tiled. A false floor 35 is provided with a plurality cf apertures to permit air to enter the spa from a source of pressurized air 36. Inlet and cutlet orifices 37 are provided for circulation of heated water. FIGS. 12-19 illustrate some of the many pool shapes which may be constructed with the apparatus and according to the method of the invention. As illustrated, the optional features of step out and/or spa may be readii'- included in the construction. A. particularly advantageous feature of the present invention resides in the retaining means for the tensioning cable. Should the cable slip downwards during the tensioning step, the coping sections may become mis¬ aligned and thus become difficult if not impossible to re- align before the grouting adhesive sets. The cable retain¬ ing brackets obviate the possibility of such a misaiignmεn-i A further advantageous feature is the provision of the apertured coping sections for use in those regions where inverse curvatures would otherwise precluce a peri etral tensioning cable. The cable, being held captive within - li ¬ the inversely curved coping section exerts an outwardly directed force under tension on the coping section which counteracts an inwardly directed force as the section undergoes compression from neighbouring coping sections. It can be readily seen therefore that the features of the present invention may be adapted to a wide variety of pool shapes while at the same time retain¬ ing structural integrity. The coping sections of the present invention are adapted to permit a wide variety of surface finishes. FIGS. 20 and 21 illustrate two different types of finishes. In FIG. 20, the inwardly projecting lip 38 may be tiled and a conventional nosing tile 39 is situated adjacent the front upper edge of the coping section. An aggregate finish 40 may be applied to the remaining upper surface of the coping section and a rebate 41 in the rear edge permits the aggregate finish to be taken over the rear portion of the coping section. Not only does this feature give the illusion of a thicker aggregrate finish but it prevents chipping of the finish at the rear edge. FIG. 21 illustrates a conventional brick finish comprising bricks 42 set in mortar 43. Although the invention has been described with reference to a swimming pool, it will be readily apparent to a skilled addressee that similar structures, with appropriate modification will be suitable for other liquid retaining purposes e.g. water or chemical storage, chemical treatment vats, settling tanks, sewerage treatment plants etc. Accordingly it will be readily apparent to a skilled addressee that many modifications may be made to the invention without departing from the spirit and scope thereof. - JRΞA

Claims: CLAIMS : 1. An apparatus for constructing a liquid retaining structure comprising: • *- a plurality of wall panels adapted for edge to edge engagement; lower retaining means for retaining the lower edges of said, panels in desired edge to edge alignment; and, a plurality of preformed coping members adapted to engage the upper edges of said wall panels to retain said wall panels in desired edge to edge alignment; said coping members adapted to support tensioning means adjacent the upper edge of said wall panels such that when said tensioning means is tensioned, said coping members act in compression to withstand inwardly directed forces en said wall panels and said tensioning means acts in tension to withstand outwardly directed forces on said wail panels . 2. An apparatus as claimed in claim 1 wherein the wall panels comprise steel fibre reinforced concrete. 3. An apparatus as claimed in claim 1 or claim 2 wherein the lower retaining means comprises a channel sectioned member. 4. An apparatus as claimed in any one of claims 1-3 wherein the coping members are provided with an aperture to engage the upper edges of said wall panels, said aperture being tapered inwardly to permit firm frictional engagement with the upper edges of said panels. 5. An apparatus as claimed in any one of claims 1-4 wherein said wall members and said coping members are formed in a plurality of complementary lateral cross-sectional shapes including straight section, concave curves and convex curves to permit construction of liquid retaining structures selected from a wide variety of peri etral shapes. 6. An apparatus as claimed in any one of claims 1-5 wherein one or more of said coping members includes a hollow aperture extending lengthwise thereof to support a - 13 - tensioning means. 7. An apparatus as claimed in any one of claims 1-6 wherein the tensioning means comprises a steel cable arranged about an outer wall of one or more of said coping members adjacent the upper edges of said wall panels and is retained in a desired position by brackets extending between adjacent edges of said coping members. 8. A liquid retaining structure comprising:- a plurality of preformed wall panels arranged in edge to edge relationship to form a wall member of pre¬ determined shape on a base; said wall panels being maintained in a desired edge to edge relationship at their respective lower edges by lower retaining means and at their respective upper edges by a plurality of preformed coping members; tensioning means arranged about outwardly facing edges of said coping members adjacent the upper edges of said wall member to permit said coping members to act in compression to withstand inwardly directed forces on the wall member and said tensioning means to act under tension to withstand outwardly directed forces on the wall member. 9. A liquid retaining structure as claimed in claim 8 wherein said liquid retaining structure is formed within a cavity in the ground and concrete is cast between the outer surface of the wall member and the cavity wall. 10. A liσuid retaining structure as claimed in claims 8 or 9 wherein the liquid retaining structure includes a concrete floor cast within the wall member. 11. A liquid retaining structure as claimed in any one of claims 8-10 wherein the floor is formed with a concave drpression. 12. A liquid retaining structure as claimed in claims 8-11 wherein the liquid retaining structure includes a liquid impervious membrane releasably retained by retaininσ means adiacent the upper part of the wall member. - 14 - 13. A liquid retaining structure as claimed in any one of claims 8-12 wherein the structure includes means for evacuating the space between the membrane and the wall and floor members . 14. A liσuid retaining structure as claimed in any one of claims 8-13 wherein the structure includes means for removal of liquid accumulated between the membrane and the wall member. 15. A method for the construction of a liquid retaining structure comprising:- arranging a plurality of preformed wall panels to form an essentially continuous wall member of pre¬ determined perimetral shape; retaining the lower edges of said wall panels in desired edge to edge relationship with lower retaining means; retaining the upper edges of said wall panels i: desired edge to edge relationship with coping members of complementary lateral cross-sectional shape; retainably positioning a tensioning means about outwardly facing walls of said coping members adjacent the upper edge of said wall panels; and, tensioning said tensioning means to permit said coping members, under compression, to withstand inwardly directed forces on said wall panels and said tensicning means, under tension, to withstand outwardly directed forces on said wall panels. 16. A method as claimed in claim 15 wherein said structure is formed within an excavation within a ground surface. 17. A method as claimed in claim 15 or claim 16 wherein concrete is cast around the external perimeter of said structure. 18. A method as claimed in any one of claims 15-17 wherein a concrete floor is cast within the perimeter of said structure. 19.. A method as claimed in any one of claims 15-18 wherein said floor is formed with a concave depression. 20. A method as claimed in any one of claims 15-19 wherein a water impervious membrane is arranged within said structure and releasably retained therein by a retaining means arranged adjacent the upper edge of said wall panels. 21. A method as claimed in any one of claims 15-20 wherein the space between the membrane and the inner wall and floor of the structure is evacuated prior to filling with liσuid.

Inventors: DURACK M
Applicants: DURACK M
Application year: 1980
Main classification: E04H3
IPC codes: E04H4