CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 61/745,254, filed December 21, 2012, and U.S. Nonprovisional Application No. 14/060,961, filed October 23, 2013. The entire contents of both applications are incorporated by reference herein.

FIELD OF THE INVENTION

[0002] The invention relates to swimming pools, spas, and storage tanks for liquids. BACKGROUND OF THE INVENTION

[0003] Above-ground swimming pools typically have a tubular support structure that supports a water-proof liner. For anything other than the smallest pools, the structures are usually difficult to erect and are prone to being damaged. The liner is especially vulnerable. In addition, unless the underlying surface is swept absolutely clean of pebbles and other debris, the liner, once laid in place, will not be smooth, which can be both unsightly and uncomfortable to the touch. If, for example, the liner is inadvertently laid over a rock or pebble, a swimmer may step on the unseen object and possibly injure himself and the liner. Remedying the situation requires a pool owner to drain the pool, remove the liner, and reassemble and fill the pool, which is quite time-consuming.

[0004] The patent literature describes a number of above-ground pool, spas, and liquid storage tanks. For example, US 4,974,266 discloses a swimming pool structure for on-site assembly, which comprises a flexible liner supported by a surrounding wall of side-by side wooden staves and a plurality of cables that pass entirely around the pool wall. US 5,054,135 discloses a molded modular plastic framework for a swimming pool, which comprises an endless molded base member having post sockets and a continuous cove, the molded members being connected end to end to make the endless base member. US 5,114,274 discloses a sewage collection and separation tank that uses a hexagonal elastomeric gasket mounted in a groove, with one end of the gasket abutting against another gasket mounted in the side of the sump pit to provide a liquid-tight seal. US patent no. 3,971,075 discloses a swimming pool structure comprising a plurality of panels forming the pool walls and floor, the panels being interconnected by elastomeric sealing members that bridge adjacent panels and contact the front faces thereof. The interconnections have a complex design that employs both a seal and a cover member. Despite these past attempts, a need remains for above ground swimming pools, spas, and related structures that do not require a liner and that are structurally sound, easy to assemble, and aesthetically pleasing.

SUMMARY OF THE INVENTION

[0005] According to one aspect of the invention, a modular swimming pool is provided and comprises at least one floor section, each floor section having a top surface, a bottom surface, and one or more sides, each side having at least one groove formed therein; a plurality of wall sections attached to the floor section(s), each wall section having at least one groove formed therein; a plurality of channels, the channels being formed by complementary pairs of the grooves in adjacent wall sections and/or floor sections; a plurality of elastomeric seals seated in the plurality of channels; and a plurality of fasteners located near each channel and securing the plurality of wall sections to each other and/or to the at least one floor section; wherein the elastomeric seals and fasteners create water-tight joints between adjacent wall sections and/or floor sections. The swimming pool is made of any suitably strong, waterproof polymer, fiberglass, or other suitable material, and is designed to be easy to assemble. Advantageously, no swimming pool liner is required.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Various features and embodiments of the invention will be more readily understood when considered in light of the accompanying drawings, wherein:

[0007] FIG. 1 is a perspective, partial sectional schematic view of a circular swimming pool according to one embodiment of the invention;

[0008] FIG. 2a is a perspective view of the front (interior side) of a pool wall section according to one embodiment of the invention;

[0009] FIG. 2b is a perspective view of the back (exterior side) of the pool wall section shown in FIG. 2a;

[0010] FIG. 2c is a close-up perspective view of a lower corner of the pool wall section shown in FIGS. 2a and 2b; [0011] FIG. 3 is a close-up sectional view of a pool wall section adjacent to a pool floor section according to one embodiment of the invention, with elastomeric seals in place between the pool wall section and the pool floor section;

[0012] FIG. 4 is a perspective view of a pool wall section and a pool floor section according to one embodiment of the invention;

[0013] FIG. 5 is a perspective, partially exploded view of a pool wall section adjacent to a pool floor section according to one embodiment of the invention, with a pair of elastomeric seals positioned to be placed within channels formed by complementary grooves between the sections;

[0014] FIG. 6 is a side view of a pool wall section and a skirt section according to one embodiment of the invention;

[0015] FIG. 7 is a top sectional view of two adjacent pool wall sections according to one embodiment of the invention;

[0016] FIG. 8 is a perspective view of the interior side of a skirt section according to one embodiment of the invention;

[0017] FIG. 9 is a side view similar to FIG. 6, showing another embodiment for joining a skirt section to a wall section;

[0018] FIG. 10 is a side view similar to FIG. 6, showing a wall section with a ladder according to one embodiment of the invention;

[0019] FIG. 11 is a schematic view of a skirt section having steps formed therein according to one embodiment of the invention;

[0020] FIG. 12 is a perspective, view of an assembled pool according to one embodiment of the invention, with two skirt sections removed; [0021] FIG. 13 is a perspective view of the embodiment shown in FIG. 12, showing additional detail of the floor support members;

[0022] FIG. 14 is a perspective, exploded view of a skirt and a wall section buttress, with skirt mounting hardware, according to one embodiment of the invention;

[0023] FIG. 15a is top plan view of a circular swimming pool according to another embodiment of the invention;

[0024] FIG. 15b is a side elevational view of the swimming pool shown in FIG. 15a;

[0025] FIG. 15c is a perspective view of the swimming pool shown in FIG. 15a;

[0026] FIG. 15d is a sectional view of the swimming pool shown in FIG. 15b, taken along line A-A;

[0027] FIG. 15e is a top view of the central floor section of the swimming pool shown in FIG. 15a;

[0028] FIG. 15f is a side view of the central floor section shown in FIG. 15e;

[0029] FIG. 15g is a bottom view of the central floor section shown in FIG. 15e;

[0030] FIG. 15h is an exploded, perspective view of the central floor section shown in FIGS. 15e-15g;

[0031] FIG. 16a is a bottom plan view of a wall section of the swimming pool shown in FIG. 15a;

[0032] FIG. 16b is a top plan view of the wall section shown in FIG. 16a; [0033] FIG. 16c is a front elevational view of the wall section shown in FIG. 16a; [0034] FIG. 16d is a side elevational view of the wall section pool shown in FIG. 16a; [0035] FIG. 16e is a rear elevational view of the wall section shown in FIG. 16a, with the outer skirt removed;

[0036] FIG. 16f is an exploded perspective view of the wall section shown in FIGS. 16a-16e, with the skirt visible;

[0037] FIG. 17a is top plan view of an oval swimming pool according to another embodiment of the invention;

[0038] FIG. 17b is a side elevational view of the swimming pool shown in FIG. 17a;

[0039] FIG. 17c is a perspective view of the swimming pool shown in FIG. 17a;

[0040] FIG. 17d is a sectional view of the swimming pool shown in FIG. 17b, taken along line B-B;

[0041] FIG. 17e is a top view of the central floor section of the swimming pool shown in FIG. 17a;

[0042] FIG. 17f is a side view of the central floor section shown in FIG. 17e;

[0043] FIG. 17g is a bottom view of the central floor section shown in FIG. 17e;

[0044] FIG. 17h is a perspective view of the central floor section shown in FIGS. 17e andl7f;

[0045] FIG. 18a is top plan view of a square swimming pool according to another embodiment of the invention;

[0046] FIG. 18b is a side elevational view of the swimming pool shown in FIG. 18a; [0047] FIG. 18c is a perspective view of the swimming pool shown in FIG. 18a; [0048] FIG. 18d is a sectional view of the swimming pool shown in FIG. 18b, taken along line C-C;

[0049] FIG. 18e is a top view of the central floor section of the swimming pool shown in FIG. 18a;

[0050] FIG. 18f is a side view of the central floor section shown in FIG. 18e;

[0051] FIG. 18g is a bottom view of the central floor section shown in FIG. 18e;

[0052] FIG. 18h is a perspective view of the central floor section shown in FIGS. 18e and 18f;

[0053] FIG. 19a is top plan view of a triangular swimming pool according to another embodiment of the invention;

[0054] FIG. 19b is a side elevational view of the swimming pool shown in FIG. 19a;

[0055] FIG. 19c is a perspective view of the swimming pool shown in FIG. 19a;

[0056] FIG. 19d is a sectional view of the swimming pool shown in FIG. 19a, taken along line D-D;

[0057] FIG. 19e is a top view of the central floor section of the swimming pool shown in FIG. 19a;

[0058] FIG. 19f is a side view of the central floor section shown in FIG. 19e;

[0059] FIG. 19g is a bottom view of the central floor section shown in FIG. 19e;

[0060] FIG. 19h is a perspective view of the central floor section shown in FIGS. 19e and 19f; [0061] FIG. 20a is top plan view of an "L-shaped" swimming pool according to another embodiment of the invention;

[0062] FIG. 20b is a side elevational view of the swimming pool shown in FIG. 19a;

[0063] FIG. 20c is a perspective view of the swimming pool shown in FIG. 19a;

[0064] FIG. 20d is a sectional view of the swimming pool shown in FIG. 19b, taken along line E-E;

[0065] FIG. 20e is a top view of the central floor section of the swimming pool shown in FIG. 19a;

[0066] FIG. 20f is a side view of the central floor section shown in FIG. 19e;

[0067] FIG. 20g is a bottom view of the central floor section shown in FIG. 19e; and

[0068] FIG. 20h is a perspective view of the central floor section shown in FIGS. I9e and 19f.

DETAILED DESCRIPTION OF THE INVENTION

[0069] According to the invention, an above-ground swimming pool, spa, or storage tank is formed of a number of modular sections. FIG. 1 shows one embodiment of such a swimming pool. The pool 10 is constructed of a central floor section 20 and multiple wall sections 30. Adjacent wall sections meet at water-tight joints or seams 70, and each wall section meets the central floor section at a water-tight seam 75. Two or more cables 80 wrap around the swimming pool and provide additional structural integrity, and a decorative skirt 90, composed of individual skirt sections 91, forms the outer perimeter of the pool.

[0070] The floor section 20 has a top surface 21, a bottom surface 22, and a side 23 (see FIG. 3). A pair of parallel grooves 24, 25 is formed in the side 23 of the floor section and, together with corresponding grooves in adjacent wall sections, forms channels that hold elastomeric seals. This is described below in more detail. In between the grooves are a plurality of holes 26, which extend all the way through the side, as described below. A foot 27 (described below) extends laterally from the floor section side, away from the center of the pool.

[0071] The side 23 of the floor section 20 extends downwardly along the perimeter of the floor section and serves as a load-bearing support member. Preferably, one or more additional support members, adapted to support the weight of the floor section and the water that will fill the pool, also extend from the bottom surface of the central floor section 20. For example, in the embodiment shown in FIGS. 13 and 14 the floor section 20 has concentric rings 28 and radially directed arms 29 extending from the bottom surface 22 of the pool. In FIGS. 15g, 15h, 17g, 18g, 19g, and 20g the floor section includes a subfloor 12 having a structure similar to a waffle or a honeycomb, with a series of crests and troughs that provide load-bearing support. Alternatively, the undersurface of the pool has some other geometry, such as parallel beams, which may be connected with crosspieces; hexagonal grids; and the like.

[0072] FIGS. 2a and 2b show front (pool-facing) and rear views of a typical wall section 30, which is substantially wedge-shaped when viewed from above. Each wall section has a main panel 31 and two side panels 32. The main panel of each wall section includes an upper portion 33, which forms a coping or sub-coping; a middle portion 34, which accounts for most of the surface area of the wall section main panel; and a lower portion 35, which is directed toward the central floor section 20. In addition, the main pool panel 31 has a front (pool-facing) surface 31a and a back or rear (outwardly facing) surface 31b. Where the main panel 31 abruptly ends at its lower portion 35„ a face 36 provides a surface that abuts the side 23 of the adjacent floor section 20. In the embodiment shown in the drawings, the lower portion 35 of the main panel forms part of the floor of the pool. In addition, the top or upper portion 33 of the main panel 31 of each wall section is wide enough to stand on and, in some embodiments, mount a ladder. In some embodiments, additional decking is mounted to this upper portion. As shown in FIGS. 1 and 2, the upper portion of the main panel includes a slight lip 37 that projects inwardly toward the center of the pool.

[0073] Each wall section 30 meets the central floor section 20 at a water-tight seam or joint 75. As is shown in detail in FIGS. 3-5, a pair of parallel grooves 38, 39 is formed in the face 36 of each wall section. These grooves complement and line up with the corresponding grooves 24, 25 in the adjacent floor panel 20, and thereby form two channels A, B. An elastomeric seal 40, 41 is seated in each channel and is compressed by the applied force of a plurality of fasteners, e.g., bolts 43, nuts 44, and washers 45. The bolts extend through holes 46 in the face 36 of each wall section and holes 26 in the side 23 of the floor section. The holes are preferably located along an imaginary line that lies between— and is parallel to— the two channels A, B. To further index each wall section 30 with the central floor section 20, a leg or support member 47 extends downwardly from each side panel of each wall section and serves as a stop for the corresponding foot 27 on the adjacent floor panel.

[0074] In a similar manner, each wall section meets two adjacent wall sections at water-tight seams or joints 70. FIGS. 2a, 2b, 2c, and 6 show a typical wall section 30, which includes a pair of side panels 32a, 32b that extend from the edge of the wall section's main panel 31. A pair of grooves, 52, 53 is formed in the outer surface of each side panel. Thus, both the left side panel 32a and the right side panel 32b of each wall section have pairs of grooves, similar to the grooves 38, 39 formed in the face 36 of each wall section. When each wall section abuts an adjacent wall section, corresponding pairs of grooves line up to form channels, and elastomeric seals are seated in the channels to form water-tight seams or joints between the wall sections.

[0075] In FIG. 7, three wall sections are positioned side by side, in a slightly exploded configuration. The view is from the top, with the interior of the pool at the bottom of the page and the wall sections depicted in cross section. (The concave curvature of the wall sections has been omitted for clarity.) For convenience, the three wall sections are labeled 130, 230, and 330, respectively. The right side panel 132b of the first (left) wall section 130 is shown; the left side panel 232a and right side panel 232b of the second (middle) wall section 230 are shown; and the left side panel 332a of the third (right) wall section 330 is shown. When the three wall sections are brought side by side, corresponding grooves in the side panels line up and form channels adapted to hold elastomeric seals, and thereby form water-tight seams or joints between the wall sections. Thus, grooves 152b and 153b in the right side panel 132b of the first wall section 130 line up with grooves 252a and 253a in the left side panel 232a of the second (middle) wall section, while grooves 352a and 353a in the left side panel 332a of the third wall section 330 line up with grooves 252b and 253b in the right side panel 232b of the second (middle) wall section 230. Where each groove lines up with a complementary groove, a channel is formed. In FIG. 7, the arrows indicate where the channels— w, x, y, z— will be formed once the wall sections are brought together completely.

[0076] An elastomeric seal 54, 55, 56, 57 is seated within each channel and compressed by the applied force of a plurality of fasteners, e.g., bolts 43, nuts, 44, and washers 45. The bolts extend through holes 58 in each side panel. As can be seen in FIG. 6, the holes are located along an imaginary line that lies between, and is parallel to, adjacent grooves or channels, e.g., between channels w and x and channels y and z. Optionally, the material in the immediate vicinity of some or all of the holes 58 is reinforced by a gusset or pair of gussets (not shown) on the non-mating face of each panel. The material near each hole 26 in the floor section(s) can be similarly reinforced.

[0077] The elastomeric seals are made of a durable, water-proof and resilient material suitable for forming a water-tight joint when compressed within a channel, similar to an O- ring or gasket. Examples of suitable materials include natural rubber, which can be crosslinked or uncrosslinked; elastomers and related copolymers; and similar materials. More specific examples include neoprene, nitrile rubber, and other elastomeric (co)polymers, which can be crosslinked or uncrosslinked.

[0078] The cross-sectional shape of the channels reflects the cross-sectional shape of the corresponding grooves that form the channels. In the embodiment shown, the grooves have semi-circular cross-sections, and the resulting channels are circular in cross-section.

Alternatively, the grooves can have a square, rectangular, triangular, semi-elliptical, or some other cross-sectional shape. In general, the elastomeric seals are sized slightly larger than the channels. This facilitates the formation of a water-tight joint between adjacent floor and wall sections and adjacent wall sections when the seals are squeezed within the channels.

[0079] As can be seen in FIGS 2c, 4, and 5, the grooves 38, 39 in the face 36 of the lower portion of a wall section meet the grooves 52, 53 in each side panel at a 90 degree angle. Consequently, the channels formed between a given wall section and an adjacent floor section are formed at right angles to— or normal to— the channels formed between adjacent wall section side panels. Advantageously, each elastomeric seal that is seated in a channel formed between adjacent wall sections ends in a concave tip 60 so that it can conform closely to the cross-sectional shape of a seal 40, 41 seated in a channel formed between a wall section and a floor section. Alternatively, it is possible to stagger or offset the grooves formed in the wall section side panels relative to the grooves formed between wall and floor sections, so that they don't meet. In that case, the elastomeric seals seated in the channels formed between adjacent wall sections can simply end in a flat tip, perpendicular to the body of each seal.

[0080] As shown in FIGS. 1 and 2b, each wall section 30 includes at least one supporting buttress 62. In the embodiments shown in FIGS. 1 and 2, each wall section has three buttresses, 62a, 62b, and 62c. Two of these (62a, 62b) are extensions of — and integral with— the left and right side panels 32a, 32b. The third buttress 62c is located in the middle of the wall section and extends outwardly from the main panel 31. At the base of each buttress, a flange or foot 63 extends laterally from the buttress and provides additional stability. When two wall sections are side by side, a buttress from the first wall section abuts a buttress from the second wall section and thereby forms a common buttress that is thicker than each adjoining buttress individually. In one embodiment, the two shared buttress can be bolted together at one or more locations. To reduce the weight of the wall sections, cutouts 64 are formed in the side panels/buttresses. The number, shape, and location of the cutouts are selected to minimize stress concentration within the side panels/buttresses.

[0081] In an alternate embodiment shown in FIG. 9, each buttress has a tubular construction, in which two or more tubes 65, 66 link the upper portion 33 of a wall section main panel 31 to a foot 67 spaced distally from and behind the lower portion 35 of the main panel of the wall section. The tubes are insertable into mating holes in the main panel, foot, and/or side panels and can be secured therein with a friction fit, threaded connections, an adhesive, or other means of connection.

[0082] To enhance the overall structural integrity of the swimming pool, a plurality of high- strength cables 80 extend around the pool. In FIGS. 1, 6, and 13, three cables are provided, located in the upper, middle, and lower portions of the pool, respectively. The pressure on the pool walls is greatest at the bottom of the pool, and cables are preferentially placed at least at the bottom third to bottom half of the height of the pool. Together with the wall section buttresses, the cables resist the outward pressure of water when the pool is filled with water. [0083] The cables— and the walls of the pool— are held in tension by tightening a plurality of turnbuckles 85 placed at various positions around the perimeter of the wall sections, distally located behind the wall sections' main panels (see FIGS. 1 and 13). A plurality of slots or holes 81 are formed in the side panels of the wall sections (and in the middle buttress 62c, if present) and provide a path for the cables 80 to encircle the pool. (See FIGS. 1, 2b, and 9.) Optionally, a bushing (not shown) in some or all of the holes 82 provides additional reinforcement. In one embodiment, ribs (not shown) extending from the outer (distal) side of the main panel can be provided to match the curvature of the cables, particularly near the turnbuckles, and provide additional structural support.

[0084] In an alternate embodiment (not shown), metal straps, similar to the kind used to secure a house water heater, are used in lieu of cables. Suitable hardware (e.g., bolts and nuts) fasten the two ends of each strap together. The cables or straps can be made of steel or another suitably strong material. To resist weathering, the cables can be galvanized, made of stainless steel, wrapped in vinyl, or protected in some other manner.

[0085] A decorative skirt 90 wraps around the circumference of the pool and hides the buttresses and the back of the wall sections. The skirt is comprised of a plurality of skirt sections 91 , each having a top end 92 bottom end 93, and two sides 94a, 94b. In one embodiment, shown in FIG. 6, a tab 95 in the top end of each skirt section 91 engages with a corresponding notch 96 in an adjacent wall section or pair of adjacent wall sections, e.g., a notch located in the upper portion 33 of the main panel 31 of a wall section, and/or in an upper portion of one or both of the wall section buttresses 62. Similarly, an inwardly directed projection or foot 97 in the bottom end 93 of each skirt section engages with a corresponding slot or recess 98 in the back of either or both buttresses of an adjacent wall section.

[0086] FIG. 8 depicts the interior (pool facing) side of a typical skirt section, with tabs 95 located along the top of the skirt section and a foot 97 running along the bottom end of the skirt section. An alternative embodiment for securing a skirt section to a wall section is shown in FIG. 9. In this case, the skirt section 91 fits snuggly into place with a simple friction fit with one or more wall sections. Optionally, each skirt section can then be secured with one or more fasteners, e.g., stainless steel screws, bolts, etc. [0087] In an alternate embodiment shown in FIG. 14, the skirt sections 91 have neither tabs nor slots, but are secured to the wall sections using skirt mounting hardware, e.g., a plurality of flanges 99 and fasteners 100. The flanges can be attached to the buttresses, wall section side panels, and/or foot to provide points of attachment for mounting the skirt sections.

[0088] The skirt 90 provides the pool with an aesthetically desirable appearance, as the outer surface can be formed to look like sand, rock, brick, wood, or any other texture or motif. In addition, the skirt imparts additional structural integrity to the pool, as the multiple skirt sections effectively lock into place all the way around the pool. Additional features, such as a ladder 105 (FIG. 10), steps 110 (FIG. 11), waterfall or slide, etc., can be formed in or mounted to one or more of the skirt sections. Alternatively, such features can be integral with or attached to one or more wall sections.

[0089] Other features common to swimming pools and spas, such as openings for skimmers, ports for air jets, ports for pool vacuum systems, drains, pumps, filters, lights, speakers, waterfalls, slides, waterfalls, etc. can be included by forming such features into one or more of the floor, wall, and/or skirt sections during manufacture, or by adding the feature(s) during assembly, with a suitable water-tight seal being provided where appropriate. Some components are sufficiently small that they can be located within the space between the back side of one or more wall sections and the adjoining skirt section(s).

[0090] FIGS. 15a-15h depicts an alternate embodiment of the invention, similar in most respects to the pool depicted in FIG. 1, but having a subfloor under the primary floor and a panel support behind the main panel of each wall section. The pool 10 has a central floor section 20 surrounded in a water-tight fashion by eight curved wall sections 30. The central floor section includes a primary floor 11 and a subfloor 12, the latter having a "waffle-like" configuration with a series of crests 13 and troughs 14 (see FIGS. 15g and 15h). A sidewall 15 extends from the outer perimeter of the primary floor, and the primary floor fits over the subfloor 12 and encompasses it like a cap. (The outer surface of the sidewall is comparable to the side 23 of the floor section shown in FIG. 3, and is labeled as such in FIG. 15h.) The subfloor' s crest-and-trough structure provides sufficient strength to withstand the pressure of water bearing down on the floor of the pool, while the primary floor has a substantially flat top surface. [0091] In the sidewall 15 of the primary floor 1 1 are a pair of grooves 24, 25. Together with corresponding pairs of grooves in the face 36 found at the lower portion of each wall section 30, the grooves define two channels that extend completely around the primary floor 11. An elastomeric seal 40, 41 sits in each channel, and the seals allow the wall sections 30 to form water-tight joints with the central floor section, essentially as described above. The sections are fastened together by a plurality of bolts (not shown) that extend through holes 26 in the primary floor's sidewall 15 and corresponding holes in the inwardly directed face 36 of each wall section, essentially as described above. The bolts are secured in place with washers and nuts (not shown).

[0092] A drain cap 16 covers a drain opening in the center of the floor and is secured thereto with a threaded connection, O-ring(s), gasket(s), or other water-tight connection. The drain cover provides access to a drain passage that extends from a point A in the subfloor to another point A' in the sidewall 15 of the primary floor. A drain pipe (not shown) may be seated in the passage. As shown in FIG. 15f, the grooves 24, 25 in the sidewall 15 of the primary floor include a slight jog or inflection (17 and 18, respectively) in the area near the opening A'. This permits a larger diameter drain pipe to extend through the space between the two grooves. Alternatively, the pool drain is not centrally located but, instead, is located in the lower portion 35 of one of the wall sections 30. This is shown in FIG. 15a, where the dotted circle 16' denotes the alternate location. In this embodiment, the drainage conduit need only extends under a single wall section, and not under the central floor section 20.

[0093] FIGS. 16a- 16f illustrate another feature of the alternate embodiment: a panel support 31c, which is attached to or integral with the back side of each wall section 30. As previously described, a typical wall section 30 includes a main panel 31 and two side panels 32a, 32b. The side panels extend outwardly away from the interior of the pool and form buttresses 62. In FIGS. 16a- 16h, the buttresses 62 are linked together at their base by a foot 63. The main panel 31 of each wall section has a front (pool facing) side 31a and a back side 3 lb. Attached to (or integral with) the back side 3 lb of the main panel 31 is a panel support 31c. In the embodiment shown in FIG. 16, the panel support 31c has a corrugated structure that strengthens the wall section. Adjacent wall sections 30 are joined together as previously described, and as depicted, for example, in FIG. 7. A skirt 90 made of multiple skirt sections 91 attaches to the back of the wall section as previously described. [0094] The invention has primarily been characterized with a reference to a circular swimming pool or spa, with a single circular floor section. However, other designs and uses are also contemplated and within the scope of the invention. For example, an oval swimming pool is shown in FIGS. 17a-17h, with components essentially identical to those described above, but with an oval primary floor 11 that fits over a subfloor 12 having an oval footprint. The pool 10 includes two "straight" wall sections 30x and eight "curved" wall sections 30y. The floor and wall sections are constructed and joined together in substantially the same manner as they are in the circular swimming pool shown in FIGS. 15 and 16.

[0095] Similarly, FIGS. 18a-18h depict a "square" swimming pool, made of a substantially square floor section 20 (though having rounded corners), four straight wall sections 3 Ox, and eight curved wall sections 30y. The floor section 20 includes a substantially square primary floor 11 and a subfloor 12 having a substantially square footprint. The floor and wall sections are constructed and joined together in substantially the same manner as previously described.

[0096] A "triangular" pool is shown in FIGS. 19a-19h and includes a triangular floor section 20 surrounded by and attached to six wall sections, including three straight wall sections 30x and three curved wall sections 30y. These are coupled to one another as previously described. The floor section 20 includes a primary floor 11 and subfloor 12. The floor and wall sections are constructed and joined together in substantially the same manner as previously described.

[0097] FIGS. 20a-20h show an "L-shaped" pool, which has an L-shaped floor section 20 and multiple walls sections, including straight sections 30x, curved (concave pool-facing) sections 30y, and curved (convex pool-facing) sections 30z. The floor and wall sections are constructed and joined together in substantially the same manner as the pools depicted in FIGS 15-19. Other shapes are possible, including asymmetrical and irregular shapes. In addition, the pool floor can be constructed of more than a single floor section. In that case, two or more floor sections are coupled together— to each other and to adjacent wall sections— using water-tight seams or joints formed in substantially the same manner as previously described. [0098] The size and number of modular floor, wall, and skirt sections described herein are selected to meet any desired pool dimension and shape, and the sections are formed of any of a number of different materials selected for water resistance, strength, structural stability, weight, ease of construction and assembly, UV resistance, resistance to chlorine and other chemicals, resistance to salt water, and/or cost. Examples include plastics, such as high density polyethylene, polypropylene, various polyolefin copolymers, polyurethane, polystyrene, ASB and other copolymers; composite materials, such as fiberglass, carbon fibers, prepreg resins, etc. One or more additives, such as UV absorbers (e.g., titanium dioxide), chlorine guards, etc., can be added. The individual floor, wall, and skirt sections are formed using any technique suitable for the material. Examples include mold injection, thermoforming, cast molding, and blow molding.

[0099] Because the pool is made of modular sections, assembly will be straightforward and relatively quick. It is estimated that, for an oval-shaped pool (16'xlO'), four man-hours will be required to assemble the pool on a flat, level surface, using common hand or power tools. The pool can also be easily disassembled for relocation. In addition, in one embodiment of the invention, some or all of the wall sections are interchangeable. As a result, a pool owner who has purchased a pool having a particular geometric shape can transform the pool into another shape by adding or removing wall sections. For example, a circular swimming pool can be transformed into an oval or square swimming pool by adding two or more "straight" wall sections. Water-tight joints are formed between adjacent wall sections and between the wall sections and the central floor section, because the grooves, channels, and elastomeric seals mate with one another in a modular fashion. Although a liner is not needed, silicone caulk can be applied to inner surface of the pool at each seam as an extra safeguard against intrusion by water, and to improve the smoothness of the joint.

[0100] It will be appreciated that a number of variations and modifications can be made without departing from the invention. For example, each wall and floor section can meet with a single channel, rather than a pair of channels, formed between the panels. Similarly, adjacent wall sections can meet with a single channel, rather than a pair of channels, formed there between. In another embodiment, three or more channels can be employed at each joint. As another example, one or more floor or wall sections can be manufactured with a plurality of threaded bolts embedded in place to ease construction. Alternatively, threaded bolts can extend through the face 36 of the wall sections 30 into threaded holes in the floor section(s) 20, without need of securing nuts. In yet another alternative, self-taping screws can extend through the holes 46 in the face 36 of each wall section, directly into the floor section(s) 20 or primary floor 1 1— without need of a corresponding hole in the floor section(s) or primary floor. As another example, the pool can include a solid or mostly solid subfloor. Also, the invention is not limited to swimming pools and spas, but also provides an improved modular structure for storing water and other liquids. Other variations are encompassed by the invention. Therefore, although the invention has been described with reference to various features and embodiments, the invention is limited only by the appended claims and equivalents thereof.