Modular Stormwater Detention Tank

Abstract

A modular stormwater detention tank made with a plurality of modular pieces, and a plurality of modular footing members. The plurality of modular pieces each have four legs supporting a flat rectangular top surface. The plurality of modular pieces are configured and arranged to abut one another to form an enclosure with a perimeter sidewall, and a flat top surface. One of the plurality of modular pieces includes an inlet for the stormwater. The plurality of modular footing members are configured to support the plurality of modular pieces, and to interlock adjacent modular pieces in position. Means for attaching the top surfaces of the modular pieces to one another may also be provided.

Description

FIELD OF THE INVENTION

[0001] The present invention relates generally to the retention or detention of fluids, particularly stormwater and other wastewater. More particularly, the present invention relates to underground stormwater detention systems for managing excess stormwater runoff.BACKGROUND OF THE INVENTION

[0002] Stormwater detention systems are engineered structures or sets of structures designed to manage excess stormwater runoff. Their primary function is to collect and temporarily hold stormwater and then release it at a controlled rate to downstream drainage systems, watercourses, or outfalls. This helps to prevent flooding and erosion by moderating the flow rate and volume of stormwater entering natural bodies of water or municipal drainage systems.

[0003] There are several types of stormwater detention systems, including:

[0004] Detention Basins: These are large, open basins that temporarily hold stormwater until it can be safely discharged at a controlled rate.

[0005] Dry Ponds: Similar to detention basins but specifically designed to drain completely after a storm event.

[0006] Wet Ponds: These function similarly to dry ponds but are designed to maintain a permanent pool of water, which can provide additional benefits like habitat for wildlife and water quality improvement.

[0007] Underground Detention Tanks: These systems use pipes, vaults, or other subsurface structures to store water beneath the ground, making them ideal for urban areas where space is limited.

[0008] The design of these systems often includes features to slow down water flow, filter pollutants, and facilitate the infiltration of water into the ground, which can recharge groundwater supplies and improve the quality of water that eventually flows into rivers, lakes, and estuaries.

[0009] If the ultimate destination cannot accommodate rainwater at the rate it is supplied during heavy rainfall, such as during a storm, an underground detention tank can be installed to store the excess rainwater and release it at an acceptable rate. The destination may be an existing waterway, such as a nearby creek, or it may be preferable for the rainwater to be directed underground or absorbed into the soil. In cases where it is desirable to direct the rainwater to an existing waterway, such as a creek, the detention tank typically includes an outlet pipe leading to, for example, a pond. Alternatively, if the goal is to direct the water into the ground, the bottom of the detention tank is usually equipped with openings that allow the water to be absorbed by the soil below when it is dry enough to accept it.

[0010] Some examples of prior art stormwater detention systems include those disclosed in: U.S. Pat. Nos. 6,991,402; and 9,580,899.

[0011] However, there remains a need for improvements in the field of stormwater detention systems.SUMMARY OF THE INVENTION

[0012] What is desired therefore, is a modular detention tank which overcomes at least some of the problems associated with the prior art, and which is cost efficient and economical to manufacture and install under ground.

[0013] In one embodiment of the present invention, there is provided a modular stormwater detention tank made with nine prefabricated modular concrete pieces, and twelve prefabricated modular concrete footing members. It should be noted that that these stated numbers of modular pieces and footing members is not limiting. Each one of the modular pieces has four legs supporting a flat rectangular top surface. This exemplary embodiment also incorporates arches and domes or semi-domes into the shapes of the modular pieces to add strength and other benefits, some of which are described in more detail below. The modular pieces are configured and arranged to abut one another to form an enclosure with a perimeter sidewall spanning four sides, and a flat top surface. One of the modular pieces is provided with an inlet for the stormwater, such as for example an inlet pipe. In some embodiments, another one of the modular pieces may be provided with an outlet, such as for example an outlet pipe. However, an outlet need not be formed in any one of the modular pieces in all applications, since it may be desirable to construct the modular detention tank with an open floor (or with openings in the floor) and allow the stormwater entering the enclosure to simply drain into the ground through the floor of the modular detention tank. Similarly, an inlet need not be formed in any one of the modular pieces in all applications. It may be desirable to construct the modular detention tank without waterproofing the top surface, allowing stormwater to simply enter the enclosure through the top surface of the modular detention tank, similar to a French drain. For example, stormwater may enter the enclosure through gaps between adjacent modular pieces in the top surface and / or drainage holes added to the top surface.

[0014] The modular footing members are configured to support the modular pieces, and to interlock adjacent modular pieces in position. Additionally, means for attaching the top surfaces of the modular pieces to one another may also be provided. This exemplary embodiment uses three different types of modular pieces (i.e. corner pieces, sidewall pieces, and center pieces), and three different types of footing members (i.e. corner footing members, side footing members, and center footing members).

[0015] Therefore, according to one aspect of the present invention, there is disclosed a modular stormwater detention tank comprising:

[0016] a plurality of modular pieces each having four legs supporting a flat rectangular top surface, said plurality of modular pieces being configured and arranged to abut one another to form an enclosure with a perimeter sidewall, and a flat top surface; and

[0017] a plurality of modular footing members for supporting said plurality of modular pieces, and configured to interlock adjacent modular pieces in position.

[0018] According to another aspect of the present invention, there is also disclosed means for attaching said top surfaces of said modular pieces to one another.BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Reference will now be made to the preferred embodiments of the present invention with reference, by way of example only, to the following drawings in which:

[0020] FIG. 1 is a perspective view of a modular detention tank according to an embodiment of the present invention;

[0021] FIGS. 2 to 5 are a sequence of perspective views showing the modular detention tank of FIG. 2 being assembled;

[0022] FIG. 6 is a perspective of a corner piece of the modular detention tank of FIG. 1;

[0023] FIG. 7 is left side view of the corner piece of FIG. 6;

[0024] FIG. 8 is a front view of the corner piece of FIG. 6;

[0025] FIG. 9 is a right side view of the corner piece of FIG. 6;

[0026] FIG. 10 is a rear view of the corner piece of FIG. 6;

[0027] FIG. 11 is a top view of the corner piece of FIG. 6;

[0028] FIG. 12 is a bottom view of the corner piece of FIG. 6;

[0029] FIG. 13 is a perspective view of a sidewall piece of the modular detention tank of FIG. 1;

[0030] FIG. 14 is a left side view of the sidewall piece of FIG. 13;

[0031] FIG. 15 is a front view of the sidewall piece of FIG. 13;

[0032] FIG. 16 is a right side view of the sidewall of FIG. 13;

[0033] FIG. 17 is a rear view of the sidewall piece of FIG. 13;

[0034] FIG. 18 is a top view of the sidewall piece of FIG. 13;

[0035] FIG. 19 is a bottom view of the sidewall piece of FIG. 13;

[0036] FIG. 20 is a perspective view of a center piece of the modular detention tank of FIG. 1;

[0037] FIG. 21 is a left side view of the center piece of FIG. 20, the front view, the right side view, and the rear view being identical;

[0038] FIG. 22 is a top view of the sidewall piece of FIG. 20;

[0039] FIG. 23 is a bottom view of the sidewall piece of FIG. 20;

[0040] FIG. 24 is a perspective view of a center footing member according an embodiment of the present invention;

[0041] FIG. 25 is a top view of the center footing member of FIG. 24, the rear view

[0042] FIG. 26 is a left side view of the center footing member of FIG. 24, the right side view being identical;

[0043] FIG. 27 is a front view of the center footing member of FIG. 24;

[0044] FIG. 28 is a rear view of the center footing member of FIG. 24;

[0045] FIG. 29 is a perspective view of a side footing member according an embodiment of the present invention;

[0046] FIG. 30 is a top view of the side footing member of FIG. 29, the rear view

[0047] FIG. 31 is a left side view of the side footing member of FIG. 29, the right side view being identical;

[0048] FIG. 32 is a front view of the side footing member of FIG. 29;

[0049] FIG. 33 is a rear view of the side footing member of FIG. 29;

[0050] FIG. 34 is a perspective view of a corner footing member according an embodiment of the present invention;

[0051] FIG. 35 is a top view of the corner footing member of FIG. 34, the rear view

[0052] FIG. 36 is a left side view of the corner footing member of FIG. 34, the right side view being identical;

[0053] FIG. 37 is a front view of the corner footing member of FIG. 34;

[0054] FIG. 38 is a rear view of the corner footing member of FIG. 34;

[0055] FIG. 39 is a detail of region A shown in FIG. 1;

[0056] FIG. 40 is a perspective view of a tension coupler according to an embodiment of the present invention;

[0057] FIG. 41 is a side view of the tension coupler of FIG. 40;

[0058] FIG. 42 is a perspective view of a corner piece according to another embodiment of the present invention;

[0059] FIG. 43 is a rear view of the corner piece of FIG. 42;

[0060] FIG. 44 is a detail of region B shown in FIG. 42;

[0061] FIG. 45 is a left side view the corner piece of FIG. 42;

[0062] FIG. 46 is a front view of the corner piece of FIG. 42;

[0063] FIG. 47 is a right side view of the corner piece of FIG. 42;

[0064] FIG. 48 is a top view of the corner piece of FIG. 42;

[0065] FIG. 49 is a bottom view of the corner piece of FIG. 42;

[0066] FIG. 50 is a perspective view of a sidewall piece according to another embodiment of the present invention;

[0067] FIG. 51 is a rear view of the sidewall piece of FIG. 50;

[0068] FIG. 52 is a detail of region C shown in FIG. 50;

[0069] FIG. 53 is a left side view the sidewall piece of FIG. 50;

[0070] FIG. 54 is a front view of the sidewall of FIG. 50;

[0071] FIG. 55 is a right side view of the sidewall piece of FIG. 50;

[0072] FIG. 56 is a top view of the sidewall piece of FIG. 50;

[0073] FIG. 57 is a bottom view of the sidewall piece of FIG. 50;

[0074] FIG. 58 is a perspective view of a center piece according to another embodiment of the present invention;

[0075] FIG. 59 is a left side view of the center piece of FIG. 58;

[0076] FIG. 60 is a detail of region D shown in FIG. 58;

[0077] FIG. 61 is a front view the center piece of FIG. 58;

[0078] FIG. 62 is a right side view of the center piece of FIG. 58;

[0079] FIG. 63 is a rear view of the center piece of FIG. 58;

[0080] FIG. 64 is a top view of the center piece of FIG. 58;

[0081] FIG. 65 is a bottom view of the center piece of FIG. 58;

[0082] FIG. 66 is a perspective view of a corner footing according to another embodiment of the present invention;

[0083] FIG. 67 is a top view of the corner footing of FIG. 66;

[0084] FIG. 68 is a left side view of the corner footing of FIG. 66;

[0085] FIG. 69 is a perspective view of a corner footing according to another embodiment of the present invention;

[0086] FIG. 70 is a top view of the corner footing of FIG. 69; and

[0087] FIG. 71 is a left side view of the corner footing of FIG. 69; and

[0088] FIG. 72 is a perspective view of a modular detention tank with an inlet pipe and an outlet pile, according to another embodiment of the present invention.DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0089] The present invention is described in more detail with reference to exemplary embodiments thereof as shown in the appended drawings. While the present invention is described below including preferred embodiments, it should be understood that the present invention is not limited thereto. In the figures, like elements are given like reference numbers. For the purposes of clarity, not every component is labelled in every figure, nor is every component of each embodiment of the invention shown where illustration is not necessary to allow persons skilled in the art to understand the invention. Orientative words such as, for example, “left”, “right”, “front”, “rear”, “top”, “bottom”, “side”, and “center” as used herein are used for clarity with reference to the orientation of elements in the figures and are not intended to be limiting.

[0090] FIG. 1 shows a modular stormwater detention tank 10 according to an embodiment of the present invention. As discussed in more detail below, the modular stormwater detention tank 10 is constructed from a plurality of modular pieces 12, and a plurality of modular footing members 14. Preferably, each of the modular pieces 12, and footing members 14 is preformed from concrete offsite and transported to the construction site for assembly. Good results have been obtained using a self-consolidating concrete (SCC), which is a highly flowable, non-segregating concrete that can spread into place, fill the mold, and encapsulate the reinforcement without any mechanical consolidation. The concrete containing fiber reinforcing (i.e. steel and / or polypropylene) is poured into the open top of a mold defining a negative of the arch shape and legs of the modular piece 12 being cast. Traditional rebar may also be used in the mold, in addition to, or as an alternative to fiber reinforcing material being included in the concrete. Using a mold with an open top, into which the concrete is poured from above, allows the modular pieces 12 to be produced in an upright position. Producing the modular pieces 12 in this way minimizes the time required to pour the concrete into the molds and allows easy removal of the cured modular pieces 12 from the molds.

[0091] At the construction site an area of earth would be excavated and the modular pieces 12 and footing members 14 assembled into the modular stormwater detention tank 10 within this excavated area. Additionally, one or more inlet and / or outlet pipes may optionally be installed in optional openings formed in the perimeter sidewall 20 of the modular stormwater detention tank 10, as discussed in more detail below. Preferably, the optional openings may be formed in sidewalls 44, 52 of the modular pieces 12, during their prefabrication at the factory. Afterwards, the excavated area, including the newly constructed modular stormwater detention tank 10, would be covered with soil.

[0092] Referring to FIGS. 2 to 5, the modular stormwater detention tank 10 is shown being assembled at the construction site. Preferably, each of the modular pieces 12 have four legs 16 supporting a flat rectangular top surface 18. The plurality of modular pieces 12 are configured and arranged to abut one another, to form an enclosure with a perimeter sidewall 20, and a flat top surface 22. The height of the perimeter sidewall 20 is determined by the combined heights of the legs 16 of the modular pieces 12 and the modular footing members 14 supporting the legs 16 of the modular pieces 12. By way of example only, the heights of the legs 16 and footing members 14 may be sized to provide a combined height, giving the flat top surface 22 of the modular stormwater detention tank 10 a height of 130 cm above the ground 24 of the excavated area. However, it is contemplated that in other embodiments of the invention, the flat top surface 22 of the modular stormwater detention tank 10 may be provided with a higher or lower height, and therefore, the heights of the modular pieces 12 and footing members 14 may vary depending on the application. For example, it is contemplated that heights of the modular pieces 12 in the range of 60 cm to 300 cm will be desirable. All such embodiments are comprehended by the present invention.

[0093] Increasing the height of the modular stormwater detention tank 10 is one way to increase the volume of stormwater the modular stormwater detention tank 10 can hold for a given area. But this may be limited by the elevation of inlet and outlet pipes, if provided. However, the volume of the modular stormwater detention tank 10 is preferably increased by adding more modular pieces 12 if the site can fit the larger area modular stormwater detention tank 10, as opposed to increasing the height of the modular stormwater detention tank 10. Typically, increasing the height of the modular stormwater detention tank 10 is done when sufficient space is not available at the site.

[0094] Once assembled, the modular stormwater detention tank 10 has a flat top surface 22 that is rectangular in shape, in plan view. In the example shown in FIG. 1, the flat top surface 22 of the modular stormwater detention tank 10 is shaped as a square. However, it will now be appreciated that the top surface 22 may be shaped as a rectangle in other embodiments of the invention, depending on the modular pieces 12 used in its construction. All such embodiments are comprehended by the present invention.

[0095] Advantageously, the flat top surface 22 may be used to support soil and other geological loads, as well as live loads, such as trees and other vegetation. Additionally, or alternatively, the flat top surface 22 may be used to support a parking lot, and / or one or more small structures, such as portable restrooms, for example.

[0096] The plurality of modular footing members 14 are provided to support the modular pieces 12 above the ground 24, and interlock adjacent modular pieces 12 in position. Advantageously, the modular footing members 14 may be sized and shaped to help distribute the load of the modular pieces 12, and the additional load carried on their top surfaces 18.

[0097] In FIG. 2, the plurality of modular footing members 14 are shown assembled on the ground 24. The plurality of modular footing members 14 define a perimeter section 26, and a center section 28. The perimeter section 26, consisting of side footing members 46 and corner footing members 48, surrounds the center section 28, which consists of center footing members 50. A first modular piece 12 (a corner piece 30) is placed in a corner, with its four legs 16 being supported by the perimeter and center section 26, 28 on a corner footing member 48, two side footing members 46, and a center footing member 50. As shown in FIG. 1, once fully assembled, the modular stormwater detention tank 10 will have four such corner pieces 30, one at each corner of the modular stormwater detention tank 10. Preferably, the plurality of modular footing members 14 of the perimeter section 26 may be arranged to define a rectangular footing (i.e. in the shape of a rectangle or a square in plan view). Most preferably, the perimeter section 26 may be formed as a continuous footing (i.e. all of the footing members 14 are positioned tightly together end-to-end). However, it is also contemplated that the perimeter section 26 may be formed as a discontinuous footing (i.e. some or all of the footing members 14 being spaced apart from one another). All such embodiments are comprehended by the present invention.

[0098] In FIG. 3, a second modular piece 12 (a sidewall piece 32) is placed adjacent the corner piece 30 to abut one another. The sidewall piece 32 is placed with its four legs 16 being supported by the perimeter and center section 26, 28 on side footing members 46 and center footing members 48. As shown in FIG. 1, once fully assembled, the modular stormwater detention tank 10 will have four such sidewall pieces 32, one between each pair of corner pieces 30.

[0099] In FIG. 4, two additional modular pieces 12 (a sidewall piece 32, and a corner piece 30) are placed in abutting contact with the previously placed modular pieces 12 and with each other. The newly added sidewall piece 32 is place between a pair of corner pieces 30. The newly added sidewall piece 32 is placed with its four legs 16 being supported by the perimeter and center section 26, 28 on side footing members 46 and center footing members 48.

[0100] In this example, as shown fully assembled in FIG. 1, the modular stormwater detention tank 10 has a sidewall piece 32 positioned between a first pair of corner pieces 30 on one side of the modular stormwater detention tank 10, and a second sidewall piece 32 positioned between a second pair of corner pieces 30 on a second side of the modular stormwater detention tank 10 opposite the first side of the modular stormwater detention tank 10.

[0101] Continuing with this example, FIG. 1 also shows a third sidewall piece 32 positioned between a third pair of corner pieces 30 on a third side of the modular stormwater detention tank 10, and a fourth sidewall piece 32 positioned between a fourth pair of corner pieces 30 on a fourth side of the modular stormwater detention tank 10 opposite the third side of the modular stormwater detention tank 10.

[0102] It is contemplated that the number of sidewall pieces 32 may vary depending on the application, with more or fewer modular pieces 12 used on any or all sides of the modular stormwater detention tank 10. However, opposed sides of the modular stormwater detention tank 10 are expected to have an equal number of sidewall pieces 32. In some embodiments of the present invention, the sidewall pieces 32 may be omitted entirely, in which case the modular stormwater detention tank 10 would consist only of the four corner pieces 30 and an appropriate number of footing members 14. All such embodiments are comprehended by the present invention.

[0103] In FIG. 5, an additional modular piece 12 (a center piece 34) is placed in abutting contact with the previously placed modular pieces 12. Its four legs 16 being supported on the center footing members 28. As shown in FIG. 1, once fully assembled, the modular stormwater detention tank 10 will have one such center piece 34 in the middle, surrounded by four corner pieces 30, and four sidewall pieces 32. Although the example in the figures shows only one center piece 34 installed, it will be appreciated that more center pieces 34 may be used in other applications. Accordingly, it is contemplated that some embodiments of the present invention may include multiple center pieces 34, surrounded by multiple sidewall pieces 32 and corner pieces 34. Furthermore, the center piece 34 may be omitted entirely in some embodiments of the present invention. In such cases the modular stormwater detention tank 10 would consist only of the four corner pieces 30, possibly some sidewall pieces 32, and an appropriate number of footing members 14. All such embodiments are comprehended by the present invention.

[0104] As mentioned above, the plurality of modular footing members 14 define a perimeter section 26, which is made up of the side footing members 46 and corner footing members 48, and a center section 28, which is made up of the center footing members 50. As best seen the plurality of modular footing members 14 of the perimeter and center sections 26, 28 all have top surfaces 36 defining voids 38 sized and shaped to interlock legs 16 of the modular pieces 12.

[0105] As best seen in FIG. 4, the center footing members 50 may preferably have a void 38 that is sized and shaped to accommodate four legs 16 of four abutting modular pieces 12. In this example, the void 38 is square-shaped, with a cross-sectional area that is slightly larger than the cross-sectional area of the four abutting legs 16. Preferably, this size difference may be set to account for the typical tolerance limits of the concrete casting process used to make both the modular pieces 12 and the modular footing members 14. What is important is that the void 38 is sized and shaped to tightly accommodate the four legs 16 of the four abutting modular pieces 12, to hold them together in a locked manner. Although the example in the figures show the void 38 in the center footing members 50 being square shaped, it is contemplated that the shape may be rectangular, circular, or another shape that is capable of tightly accommodating four legs 16 of four abutting modular pieces 12, to help prevent the modular pieces 12 from moving out of abutting contact with each other. All such embodiments are comprehended by the present invention.

[0106] Similarly, the side footing members 46 may preferably have a void 38 that is sized and shaped to accommodate two legs 16 of two abutting modular pieces 12. In this example, the void 38 consists of a square-shaped leg portion 40 for tightly accommodating the legs 16 of the two abutting sidewall pieces 32, and channel portions 42 extending therefrom for accommodating sidewalls 44 of the two abutting sidewall pieces 32. As above, the leg portions 40 and channels portions 42 are preferably slightly larger than the legs 16 and sidewalls 44 of the two abutting sidewall pieces 32 to account for the typical tolerance limits of the concrete casting process used to make both the sidewall pieces 32 and the side footing members 50.

[0107] What is important is that the void 38 is sized and shaped to tightly accommodate the two legs 16 of the two abutting sidewall pieces 32, to hold them together in a locked manner. Although the example in the figures show the void 38 in the center footing members 50 being square shaped, it is contemplated that the shape may be rectangular, circular, or another shape that is capable of tightly accommodating two legs 16 of two abutting modular pieces 12, to help prevent the sidewall pieces 32 from moving out of abutting contact with each other. All such embodiments are comprehended by the present invention.

[0108] Preferably, the plurality of footing members 14 includes four corner footing members 48. Like the side footing members 46, the corner footing members 48 may preferably also include a void 38 consisting of a leg portion 40, and channel portions 42 extending therefrom for accommodating the sidewalls 52 of a corner piece 30.

[0109] It will now be appreciated, that a sidewall piece 32 may straddle two side footing members 46 to hold the two side footing members 46 together in relative position. Similarly, a corner piece 30 may straddle a corner footing member and a pair of adjacent side footing members 46 together to maintain their relative positions. In this way, the plurality of footing members 14 and the plurality of modular pieces 12 interlock to hold the modular stormwater detention tank 10 securely together.

[0110] Referring now to FIGS. 6-12, there is shown a corner piece 30 according to an embodiment of the present invention. The corner piece 30 has a flat rectangular top surface 18, supported by four legs 16. In this example, the flat rectangular top surface 18 is square-shaped in plan view. However, as discussed below, the flat rectangular top surface 18 may also be shaped in the form of a rectangle in plan view in other embodiments of the present invention. Preferably, the flat rectangular top surface 18 of the corner piece 30 extends over, and covers an area encompassing the legs 16, as shown. In this way, the corner piece 30 may be placed in abutting contact with adjacent modular pieces 12, which also have flat rectangular top surfaces 18, allowing a flat top surface 22 in the fully assembled modular stormwater detention tank 10. The corner piece 30 also has a pair of sidewalls 52, which enclose the space between two legs on two sides of the corner piece 30. The corner piece 30 is open on two sides, with spaces defined between the legs 16 on the two sides. Preferably, the side openings are in the form of arches. By way of example, the top of each arch may be elliptical, with a major axis of 110.8 cm and a minor axis of 91.8 cm. Its tangent descends at a 4-degree angle, widening to 120.0 cm at the bottom.

[0111] Referring now to FIGS. 13-19, there is shown a sidewall piece 32 according to an embodiment of the present invention. The sidewall piece 32 has a flat rectangular top surface 18, supported by four legs 16. In this example, the flat rectangular top surface 18 is square-shaped in plan view. However, as discussed below, the flat rectangular top surface 18 may also be shaped in the form of a rectangle in plan view in other embodiments of the present invention. Preferably, the flat rectangular top surface 18 of the sidewall piece 32 extends over, and covers an area encompassing the legs 16, as shown. In this way, the sidewall piece 32 may be placed in abutting contact with adjacent modular pieces 12, which also have flat rectangular top surfaces 18, allowing a flat top surface 22 in the fully assembled modular stormwater detention tank 10. The sidewall piece 32 preferably also has a sidewall 44, which encloses the space between two legs 16 on one side of the sidewall piece 32. The sidewall piece 32 is open on three sides, with a space defined between the legs 16 on the three sides. Preferably, the three side openings are in the form of arches. By way of example, the top of each arch may be elliptical, with a major axis of 110.8 cm and a minor axis of 91.8 cm. Its tangent descends at a 4-degree angle, widening to 120.0 cm at the bottom.

[0112] Referring now to FIGS. 20-23, there is shown a center piece 34 according to an embodiment of the present invention. The center piece 34 has a flat rectangular top surface 18, supported by four legs 16. In this example, the flat rectangular top surface 18 is square-shaped in plan view. However, as discussed below, the flat rectangular top surface 18 may also be shaped in the form of a rectangle in plan view in other embodiments of the present invention. Preferably, the flat rectangular top surface 18 of the center piece 34 extends over, and covers an area encompassing the legs 16, as shown. In this way, the center piece 34 may be placed in abutting contact with adjacent modular pieces 12, which also have flat rectangular top surfaces 18, allowing a flat top surface 22 in the fully assembled modular stormwater detention tank 10. The center piece 34 is open on all sides, with spaces defined between the legs 16 on all four sides. Preferably, the four side openings are in the form of arches. By way of example, the top of each arch may be elliptical, with a major axis of 110.8 cm and a minor axis of 91.8 cm. Its tangent descends at a 4-degree angle, widening to 120.0 cm at the bottom.

[0113] Preferably, the plurality of modular pieces 12 may include arches, domes, and semi-domes to support their top surfaces 18, as in the examples shown in the figures. Concrete has a long history of being a durable building material due to its great strength when placed in compression. The use of arches, domes and semi-domes can maximize the effectiveness of the modular stormwater detention tank 10. The use of domes and arches in the modular pieces 12 also helps to minimize the use of steel and fiber reinforcing, as they cause most of the modular piece 12 to be in compression.

[0114] For ease of producing the modular pieces 12, and constructing the modular stormwater detention tank 10, flat surfaces are also desirable. For example, the flat top surfaces 18 of the modular pieces 12 allow for simplified waterproofing options and ease of maneuvering on top of the modular stormwater detention tank 10 during assembly. Additionally, designing the modular pieces 12 with large arches and flat top surfaces 18 allows them to be produced in an upright position using a mold with an open top, into which the concrete is poured from above. Producing the modular pieces 12 in this way minimizes the time required to pour the concrete into the molds and allows easy removal of the cured modular pieces 12 from the molds.

[0115] Referring now to FIGS. 24-28, there is shown a center footing member 50, according to an embodiment of the present invention. In this example, the center footing member 50 is a preformed rectangular concrete slab with a void 38 formed in its top surface 36. The void 38 is a square-shaped portion 40 formed in the center of the top surface 36. The center footing member 50 is 150.0 cm long, 60.0 cm wide, and 30.0 cm deep. The square-shaped portion 40 is 32.0 cm long, 32.0 cm wide, and 5.0 cm deep.

[0116] Referring now to FIGS. 29-33, there is shown a side footing member 46, according to an embodiment of the present invention. In this example, the side footing member 46 is a preformed rectangular concrete slab with a void 38 formed in its top surface 36. The void 38 includes a square-shaped portion 40 and two channel portions 42 extending outward from the square-shaped portion 40. The side footing member 46 is 150.0 cm long, 60.0 cm wide, and 30.0 cm deep. The square-shaped portion 40 is 32.0 cm long, 32.0 cm wide, and 5.0 cm deep, and both channel portions 42 are 59.5 cm long, 16.0 cm wide, and 5.0 cm deep.

[0117] Referring now to FIGS. 34-38, there is shown a corner footing member 48, according to an embodiment of the present invention. In this example, the corner footing member 48 is a preformed L-shaped concrete slab with a void 38 formed in its top surface 36. The void 38 includes a square-shaped portion 40 and two channel portions 42 extending outward from the square-shaped portion 40. The corner footing member 48 is 112.5 cm long, 112.5 cm wide, and 30 cm deep. The square-shaped portion 40 is 32.0 cm long, 32.0 cm wide, and 5.0 cm deep, and both channel portions 42 are 90.5 cm long, 16.0 cm wide, and 5.0 cm deep.

[0118] It will now be appreciated that the plurality of modular pieces 12 of the modular stormwater detention tank 10 are held in position by interlocking with the plurality of modular footing members 14. Preferably, however, the plurality of modular pieces 12 are also held together at their top surfaces 18. As best seen in FIG. 39, the modular pieces 12 may preferably include means for attaching the top surfaces 18 of the modular pieces 12 together. Preferably, the attachment means comprises at least one anchor member 54 attached to the top surface 18 of each of the abutting modular pieces 12, and at least one tension coupler 56 connecting the anchor members 54 together.

[0119] With continued reference to FIG. 39, the attachment means preferably further includes an anchor void 58 in the top surface 18 surrounding each anchor member 54, and a channel 60 extending from each anchor void 58 to an edge 62 of the top surface 18. FIGS. 42-44 provide alternative views to aid in the understanding of these features. Preferably, the anchor voids 58 and channels 60 may be sized to contain the tension couplers 56 below the top surface 22 of the modular stormwater detention tank 10. Such an arrangement of anchor voids 58, anchor members 54, channels 60, and tension couplers 56 allows the attachment means to sit flush with the top surface 22 of the modular stormwater detention tank 10. Having the attachment means flush with the top surface 22 makes it easier to apply a waterproofing membrane to the top surface 22 of the modular stormwater detention tank 10 in embodiments where such waterproofing is desirable. However, it is contemplated that in other embodiments, including for example those where waterproofing is not needed, the attachment means need not be flush with the top surface 22, meaning that the anchor voids 58 and channels 60 may be omitted entirely. All such embodiments are comprehended by the present invention.

[0120] By way of example, the anchor members 54 may be lifting anchors such as Swift Lift® anchors. The anchor members 54 may be incorporated into the plurality of modular pieces 12 in a way that allows them to serve two functions; first, to facilitate lifting and placing the plurality of modular pieces 12 in position, and second, to help hold the plurality of modular pieces 12 together in abutting contact with one another, allowing the top surfaces 18 of the plurality of modular pieces 12 to join together and form a flat, top surface 22 in the fully assembled modular stormwater detention tank 10, as shown in FIG. 1.

[0121] Referring to FIGS. 40 and 41, the preferred tension coupler 56 is a turnbuckle, which is a device typically used to adjust the tension or length of ropes, cables, or tie rods. It consists of a metal frame 64 with two threaded eye bolts 66, one screwed into each end of the metal frame 64, allowing for precise adjustments by rotating the metal frame 64 to either tighten or loosen the tension.

[0122] FIGS. 42-49 show a corner piece 30′ according to another embodiment of the present invention. The corner piece 30′ has a flat rectangular top surface 18, supported by four legs 16. In this example, the flat rectangular top surface 18 has a shape in the form of a rectangle in plan view. Preferably, the flat rectangular top surface 18 of the corner piece 30′ extends over, and covers an area encompassing the legs 16, as shown. In this way, the corner piece 30′ may be placed in abutting contact with adjacent modular pieces 12, which also have flat rectangular top surfaces 18, allowing a flat top surface 22 in the fully assembled modular stormwater detention tank 10. The corner piece 30′ also has a pair of sidewalls 52, which enclose the space between two legs on two sides of the corner piece 30. The corner piece 30′ is open on two sides, with spaces defined between the legs 16 on the two sides. Preferably, the two side openings are in the form of arches. By way of example, the top of each arch may be elliptical, with a major axis of 110.8 cm and a minor axis of 91.8 cm. Its tangent descends at a 4-degree angle, widening to 120.0 cm at the bottom.

[0123] FIGS. 50-57 show a sidewall piece 32′ according to another embodiment of the present invention. The sidewall piece 32′ has a flat rectangular top surface 18, supported by four legs 16. In this example, the flat rectangular top surface 18 has a shape in the form of a rectangle in plan view. Preferably, the flat rectangular top surface 18 of the sidewall piece 32′ extends over, and covers an area encompassing the legs 16, as shown. In this way, the sidewall piece 32′ may be placed in abutting contact with adjacent modular pieces 12, which also have flat rectangular top surfaces 18, allowing a flat top surface 22 in the fully assembled modular stormwater detention tank 10. The sidewall piece 32′ preferably also has a sidewall 44, which encloses the space between two legs 16 on one side of the sidewall piece 32′. The sidewall piece 32′ is open on three sides, with a space defined between the legs 16 on the three sides. Preferably, the three side openings are in the form of arches. By way of example, the top of each arch may be elliptical. On the long side each elliptical arch may have a major axis of 110.8 cm and a minor axis of 91.8 cm. Its tangent descends at a 4-degree angle, widening to 120.0 cm at the bottom. On the short side the top of the arch may have a major axis of 105.4 cm and a minor axis of 81.7 cm. Its tangent descends at a 4-degree angle, widening to 90.0 cm at the bottom.

[0124] FIGS. 58-65 show a center piece 34′ according to an embodiment of the present invention. The center piece 34′ has a flat rectangular top surface 18, supported by four legs 16. In this example, the flat rectangular top surface 18 has a shape in the form of a rectangle in plan view. Preferably, the flat rectangular top surface 18 of the center piece 34′ extends over, and covers an area encompassing the legs 16, as shown. In this way, the center piece 34′ may be placed in abutting contact with adjacent modular pieces 12, which also have flat rectangular top surfaces 18, allowing a flat top surface 22 in the fully assembled modular stormwater detention tank 10. The center piece 34′ is open on all sides, with spaces defined between the legs 16 on all four sides. By way of example, the top of each arch may be elliptical. On the long side each elliptical arch may have a major axis of 110.8 cm and a minor axis of 91.8 cm. Its tangent descends at a 4-degree angle, widening to 120.0 cm at the bottom. On the short side the top of each arch may have a major axis of 105.4 cm and a minor axis of 81.7 cm. Its tangent descends at a 4-degree angle, widening to 90.0 cm at the bottom.

[0125] FIGS. 66-68 show a corner footing member 48′, according to another embodiment of the present invention. In this example, the corner footing member 48′ is a preformed L-shaped concrete slab with a void 38 formed in its top surface36. One arm of the L-shape is longer than the other. The void 38 includes a square-shaped portion 40 and two channel portions 42 extending outward from the square-shaped portion 40. The corner footing member 48 is 112.5 cm long, 97.5 cm wide, and 30.0 cm deep. The square-shaped portion 40 is 31.0 cm long, 31.0 cm wide, and 5.0 cm deep, and both channel portions 42 are 44.5 cm long, 16.0 cm wide, and 5.0 cm deep.

[0126] FIGS. 69-71 show a corner footing member 48′, according to yet another embodiment of the present invention. In this example, the corner footing member 48′ is a preformed L-shaped concrete slab with a void 38 formed in its top surface 36. One arm of the L-shape is longer than the other. The void 38 includes a square-shaped portion 40 and two channel portions 42 extending outward from the square-shaped portion 40. The corner footing member 48 is 97.5 cm long, 112.5 cm wide, and 30 cm deep. The square-shaped portion 40 is 31 cm long, 31 cm wide, and 5.0 cm deep, and both channel portions 42 are 59.5 cm long, 16.0 cm wide, and 5.0 cm deep.

[0127] Having described the components of the modular stormwater detention tank 10, it will now be understood that modular pieces 12 and the modular footing members 14 may preferably be prefabricated in a factory, then delivered to and assembled on site. The modular footing members 14 aid in aligning adjacent modular pieces 12 into abutting contact with one another, by placing their legs 16 in the correct positions. Additionally, the modular footing members 14 allow adjacent modular pieces 12 to support each other under load. Anchor members 54 located in the top surfaces 18 at the corners of the modular pieces 12 can be used for lifting and positioning the modular pieces 12 during assembly, and also provide a secondary locking system to hold the modular pieces 12 together.

[0128] If it is desired for the modular stormwater detention tank 10 to direct stormwater into the ground 24, the ground inside the modular stormwater detention tank 10 can be left as is, allowing natural infiltration and drainage.

[0129] On the other hand, if it is desired for the modular stormwater detention tank 10 to hold stormwater, a watertight floor may be constructed inside the modular stormwater detention tank 10, for example, by pouring concrete or laying concrete slab sections. Additional waterproofing can be achieved by applying a flat membrane such as Mel-Rol®, manufactured by W. R. Meadows, Inc., to the perimeter sidewall 20 and the top surface 22, which overlaps the gaps between the abutting modular pieces 12 forming the modular stormwater detention tank 10. Furthermore, the waterproofing membrane may be applied to the bottom of the modular stormwater detention tank 10, for example by laying it down on the ground first and constructing the modular stormwater detention tank 10 on top, before pouring concrete or laying concrete slab sections on top of the waterproofing Membrane.

[0130] Furthermore, an inlet pipe 68 and / or an outlet pipe 70 may optionally be joined to any of the sidewalls of the modular stormwater tank 10, as in the example shown in FIG. 72. Inlet and outlet pipes 68, 70 may preferably be standard stormwater pipes made of plastic, concrete or metal. Their size is limited to what can fit in the height of the perimeter sidewall 20 of the modular stormwater detention tank 10. They are joined to the perimeter sidewall 20 in the same manner as used in conventional concrete stormwater detention tank construction, namely, by joining the pipe to an opening or a flexible connector in the perimeter sidewall 20. An opening in the perimeter sidewall 20 may be made by cutting or coring out the opening, either on site or off site. Alternatively, the opening may be made off site by forming an appropriately sized and shaped void in the sidewall of a modular piece 12 during the casting process. Concrete pipes are typically available in 8-foot lengths, and diameters ranging from 8 inches to 36 inches. Plastic pipes are typically available in 20-foot lengths, and diameters ranging from 8 inches to 36 inches.

[0131] As indicated above, an inlet pipe 68 may not be needed in embodiments of the invention where the modular stormwater detention tank 10 is configured to allow stormwater to enter through the top surface 22. For example, in some embodiments, the top surface 22 is left without waterproofing to allow stormwater to pass through the top surface 22 from the outside to the inside of the modular stormwater detention tank 10, particularly through gaps between adjacent modular pieces 12. Similarly, an outlet pipe 70 may not be needed in embodiments of the invention where the modular stormwater detention tank 10 is configured to allow stormwater to drain from the bottom of the modular stormwater detention tank 10. However, in embodiments where the modular stormwater detention tank 10 includes an inlet pipe 68 and an outlet pipe 70, it is preferable that the outlet pipe 70 has a smaller diameter than the inlet pipe 68 to allow the stormwater to build up inside the modular stormwater detention tank 10 by reducing the outflow from the modular stormwater detention tank 10 relative to the inflow. By way of example, the diameter of the outlet pipe 70 may be less than half the diameter of the inlet pipe 68.

[0132] While reference has been made to various preferred embodiments of the invention, other variations, implementations, modifications, alterations and embodiments are comprehended by the broad scope of the appended claims. Some of these have been discussed in detail in this specification and others will be apparent to those skilled in the art. Those of ordinary skill in the art having access to the teachings herein will recognize these additional variations, implementations, modifications, alterations and embodiments, all of which are within the scope of the present invention, which invention is limited only by the appended claims.

Claims

1. A modular stormwater detention tank comprising:a plurality of modular pieces each having four legs supporting a flat rectangular top surface, said plurality of modular pieces being configured and arranged to abut one another to form an enclosure with a perimeter sidewall, and a flat top surface; anda plurality of modular footing members for supporting said plurality of modular pieces, and configured to interlock adjacent modular pieces in position.

2. The modular stormwater detention tank as claimed in claim 1, wherein said plurality of modular pieces includes four corner pieces.

3. The modular stormwater detention tank as claimed in claim 2, wherein said plurality of modular pieces further includes one or more modular pieces selected from the group consisting of a center piece and a sidewall piece.

4. The modular stormwater detention tank as claimed in claim 3, wherein said plurality of modular footing members includes four corner footing members.

5. The modular stormwater detention tank as claimed in claim 4, wherein each of said corner footing members has a top surface defining a void sized and shaped to interlock one leg and two sidewalls of one of said four corner pieces.

6. The modular stormwater detention tank as claimed in claim 4, wherein said plurality of modular footing members further includes one or more modular footing members selected from the group consisting of a center footing member and a side footing member.

7. The modular stormwater detention tank as claimed in claim 6, comprising four of said modular pieces abutting one another;wherein said center footing member has a top surface defining a rectangular void sized and shaped to interlock the legs of said four abutting modular pieces.

8. The modular stormwater detention tank as claimed in claim 6, comprising a pair of said sidewall pieces abutting one another, each said sidewall piece having a leg and a sidewall;wherein said side footing member has a top surface defining a void sized and shaped to interlock said leg and sidewalls of said pair of abutting sidewall pieces.

9. The modular stormwater detention tank as claimed in claim 1, wherein said plurality of modular footing members are arranged to define one of a) a continuous rectangular footing, and b) a discontinuous rectangular footing.

10. The modular stormwater detention tank as claimed in claim 1, wherein said plurality of modular pieces, and said plurality of modular footing members are made from concrete.

11. The modular stormwater detention tank as claimed in claim 1, wherein said rectangular top surface is shaped as one of a square, and a rectangle.

12. The modular stormwater detention tank as claimed in claim 3, wherein at least one said sidewall piece is positioned between a first pair of said corner pieces on a first side of said tank, and at least one said sidewall piece is positioned between a second pair of said corner pieces on a second side of said tank opposite said first side of said tank.

13. The modular stormwater detention tank as claimed in claim 12, wherein at least one sidewall piece is positioned between a third pair of said corner pieces on a third side of said tank, and at least one sidewall piece is positioned between a fourth pair of said corner pieces on a fourth side of said tank opposite said third side of said tank.

14. The modular stormwater detention tank as claimed in claim 13, wherein at least one center piece is positioned between said corner pieces and said sidewall pieces.

15. The modular stormwater detention tank as claimed in claim 14, wherein a plurality of said center pieces are surrounded by a plurality of said sidewall pieces and a plurality of said corner pieces.

16. The modular stormwater detention tank as claimed in claim 1, wherein the flat rectangular top surface of each said modular piece extends over, and covers an area encompassing the legs of the modular piece.

17. The modular stormwater detention tank as claimed in claim 1, configured to support soil, a geological load, a live load, a parking lot, a small structure, or a combination thereof, on said flat top surface.

18. The modular stormwater detention tank as claimed in claim 1, further comprising an inlet pipe attached to one of said plurality of modular pieces for directing said stormwater inside said enclosure.

19. The modular stormwater detention tank as claimed in claim 1, further comprising means for attaching said top surfaces of said modular pieces to one another.

20. The modular stormwater detention tank as claimed in claim 19, wherein said attachment means comprises:a) at least one anchor member attached to said top surface of each of said modular pieces; andb) at least one tension coupler connecting said anchor members together.

21. The modular stormwater detention tank as claimed in claim 20, wherein said attachment means further comprises a void in said top surface surrounding said at least one anchor member, and a channel extending from said void to an edge of said top surface.

22. The modular stormwater detention tank as claimed in claim 20, wherein said anchor members are lifting anchors.

23. The modular stormwater detention tank as claimed in claim 20, wherein said tension coupler is a turnbuckle.

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