Patent Grant
9617722
1. Technical Field
The present disclosure relates to underground fluid transfer systems and, in particular, to a manhole base assembly forming a junction between underground pipes and a manhole.
2. Description of the Related Art
Underground pipe systems are used to convey fluids in, e.g., municipal waterworks systems, sewage treatment systems, and the like. In order to provide access to underground piping systems for inspection, maintenance and repair, manholes placed at a street level grade can be opened to reveal manhole risers which descend to a manhole base. The manhole base typically forms a junction between two or more pipes of the underground piping system, as well as the upwardly-extending risers.
Existing manhole base structures are formed as precast cylindrical structures, with additional cylindrical and/or cone shaped risers which may be attached to the manhole base to traverse a vertical distance between the buried manhole base and the street grade above. At street grade, a manhole frame and cover may be used to provide access to the riser structures and manhole base.
In addition to providing access via manholes, manhole bases may be used when a pipeline needs to change direction and/or elevation along its underground run. In this application, the manhole base structure may contain two or more non-coaxial openings for connections to pipes. Seals may be used between the manhole base structure and the adjacent attached pipes to provide fluid-tight seals at the junctions. In order to facilitate flow of fluid between the two pipes through the manhole base structure, interior fluid channels or “inverts” may be provided within the manhole base, extending between the pipe openings.
Existing manhole base structures are cast as relatively large, cylindrical concrete castings. Fluid flow channels may be custom formed using large coring machines to drill holes in the sides of the cast concrete structures at desired locations. Alternatively, the cylindrical concrete castings may be cast using individualized forms for each individual casting configuration. The forms are stripped from the castings after the concrete has set. Because the holes are bored through the cylindrical outer profile of the casting, seals are mounted along the interior perimeter of the holes after the holes are bored. Expansion bands and mechanisms may be used to engage seals in a fluid-tight relationship with the interior surfaces of the bored holes. However, in some cases, such as for very large diameter openings, expansion mechanisms may not be a viable option, particularly due to the cylindrical profile of the outer diameter of the cast manhole base.
Previous efforts have focused on the creation of a manhole base structure which is cast in individualized form sets corresponding to the individual base structure geometry. These individualized form sets provide a non-cylindrical outer surface to the finished casting, and in particular, planar surfaces are provided for the pipe aperture openings into the base structure fluid channel. This arrangement may use pipe seals cast into the concrete material adjacent the pipe aperture, which obviates the need to bore holes in the manhole base after casting, as well as for the use of separate seals and expansion bands typically associated with standard cylindrical manhole base structures as described above. Individualized form sets are not amenable to variable geometry (e.g., elevation and angle) of the pipe apertures, and therefore separate forms are used for each desired geometrical arrangement of the base structure. Thus, individualized form sets associated with such non-cylindrical manhole structures are expensive, numerous to inventory, and not compatible with pre-existing casting equipment.
What is needed is an improvement over the foregoing.
The present disclosure provides a manhole base assembly and a method for making the same in which a non-cylindrical, low-volume concrete base is fully lined to protect the concrete against chemical and physical attack while in service. This lined concrete manhole base assembly may be readily produced using a modular manhole form assembly which can be configured for a wide variety of geometrical configurations compatible with, e.g., varying pipe angles, elevations and sizes. The form assembly is configurable to provide any desired angle and elevation for the pipe apertures using existing, standard sets of form assembly materials, and may also be used in conjunction with industry-standard cylindrical casting jackets for compatibility with existing casting operations. The resulting system provides for flexible, modular construction of a wide variety of lined manhole base assemblies at minimal cost, reduced concrete consumption and reduced operational complexity. The modular nature of the production form assembly also facilitates reduced inventory requirements when various manhole base assembly geometries are needed.
In one form thereof, the present disclosure provides a manhole base assembly includes: a concrete base comprising an upper opening, a first pipe opening below the upper opening, and a second side opening below the upper opening, characterized in that the concrete base has a non-cylindrical overall outer profile, and further characterized by: a polymeric liner received within the concrete base, the liner comprising: an entry aperture aligned with the upper opening of the concrete base; and a first side wall positioned radially outside the entry aperture and having a first pipe aperture therethrough, the first pipe aperture below the entry aperture and aligned with the first side opening of the concrete base; a second side wall positioned radially outside the entry aperture and having a second pipe aperture therethrough, the second pipe aperture below the entry aperture and aligned with the second side opening of the concrete base; a top wall extending radially outwardly from the entry aperture to the at least two side walls; and a flow channel extending between the first pipe aperture and the second pipe aperture, the flow channel in fluid communication with the entry aperture.
In one aspect of above-described system, the concrete base defines a plurality of discrete base thicknesses as measurable throughout a volume of the concrete base defining the non-cylindrical overall outer profile; the plurality of thicknesses define an average base thickness in the aggregate; and the plurality of discrete base thicknesses vary from the average base thickness by no more than 100%, whereby the concrete base has a low-variability overall thickness.
In another aspect of above-described system, the liner is formed from a composite material including an inner layer and an outer layer joined to the outer layer. The inner layer of the liner may be a polymer material and the outer layer of the liner may be fiberglass.
In yet another aspect of above-described system, the concrete base has a non-cylindrical peripheral boundary.
In still another aspect, the above-described system further includes a plurality of reinforcement rods forming a reinforcement assembly at least partially surrounding the liner and fixed to the liner, the reinforcement assembly cast into the concrete base, whereby the liner and the concrete base are integrally joined to one another via the reinforcement assembly. The liner may include a plurality of anchors each having a connection portion fixedly connected to the liner and an anchoring portion fixed to the reinforcement assembly, such that the plurality of anchors fix the reinforcement assembly to the liner. The reinforcement assembly may include a plurality of subassemblies attachable to the liner and to one another.
In another aspect of the above-described system, the entry aperture of the liner comprises a tubular structure extending upwardly away from the flow channel; and the entry aperture includes a bench disposed within the entry aperture, the bench defining a surface extending inwardly from a wall of the tubular structure toward a longitudinal axis of the tubular structure. The liner may have a back wall extending downwardly from an inner edge of the bench, such that a void is created within a periphery of the entry aperture and below the bench, the manhole base assembly further comprising a concrete displacement wedge disposed adjacent with the back wall and within the void.
In still another aspect of the above-described system, the concrete base comprises planar side walls having the first and second pipe openings formed therein respectively. The system may also include a plurality of gaskets respectively disposed at the first pipe aperture and the second pipe aperture and adapted to receive a pipe of a pipe system, one of the plurality of gaskets extending across each of the planar side walls of the concrete base. Each of the gaskets may include an anchoring section adjacent to a rim of the neighboring pipe aperture and anchored within the concrete base around the periphery of the first or second pipe opening; and a sealing section extending outwardly away from the anchoring section and the concrete base.
In yet another aspect, the above-described system may include a manhole form assembly for production of the manhole base assembly, the manhole form assembly including: a plurality of aperture supports sized to fit in the first pipe aperture and the second pipe aperture respectively, each having a portion protruding outwardly from one of the first pipe aperture and the second pipe aperture, the plurality of aperture supports each having one of the plurality of gaskets received thereon; a first forming plate secured to one of the plurality of aperture supports and adjacent to the first pipe aperture, the first forming plate having a back edge and an opposing front edge; a second forming plate secured to another one of the plurality of aperture supports and adjacent to the second pipe aperture, the second forming plate having a back edge and an opposing front edge; a back wall extending partially around the liner from the back edge of the first forming plate to the back edge of the second forming plate; and a front wall extending partially around the liner from the front edge of the first forming plate to the front edge of the second forming plate, the first forming plate, the second forming plate, the back wall and the front wall and the liner forming a pre-casting assembly in which a non-cylindrical peripheral boundary is formed around the liner with the entry aperture forming an open upper end of the pre-casting assembly, and the non-cylindrical peripheral boundary of the pre-casting assembly is sized to be received in a casting jacket.
In another aspect, the above-described manhole form assembly may further include the casting jacket formed as a cylinder, such that when the pre-casting assembly is received in the casting jacket, a first void bounded by the first forming plate and the casting jacket, a second void bounded by the second forming plate and the casting jacket, a third void at least partially bounded by the front wall and the casting jacket, and a fourth void bounded by the back wall and the casting jacket.
In another aspect of the above-described manhole form assembly, the back wall may have a hinged wall comprising a plurality of segments including a first segment, a last segment, and at least one intermediate segment between the first segment and the last segment, the plurality of segments hingedly connected to one another about a vertical axis.
In another form thereof, the present disclosure provides a manhole form assembly for production of a manhole base in accordance with the present disclosure, the manhole form assembly including: a plurality of aperture supports sized to fit in the plurality of pipe apertures respectively, each having a portion protruding outwardly from the pipe apertures and having one of the gaskets received thereon; a first forming plate secured to one of the plurality of aperture supports and adjacent to one of the pipe apertures, the first forming plate having a back edge and an opposing front edge; a second forming plate secured to another one of the plurality of aperture supports and adjacent to another one of the pipe apertures, the second forming plate having a back edge and an opposing front edge; and a back wall extending partially around the liner from the back edge of the first forming plate to the back edge of the second forming plate; the first forming plate, the second forming plate and the back wall and the liner form a pre-casting assembly in which a non-cylindrical peripheral boundary is formed around the liner with the entry aperture forming an open upper end of the pre-casting assembly, and the non-cylindrical peripheral boundary of the pre-casting assembly is sized to be received in a casting jacket.
In one aspect, the above-described system further includes a front wall extending partially around the liner from the front edge of the first forming plate to the front edge of the second forming plate, the front wall forming a part of the pre-casting assembly.
In another aspect, the plurality of aperture supports of the above-described system are joined to one another by a tie rod joined to a first aperture support at a first rod end and a second aperture support at a second rod end, such that the tie rod extends through the flow channel.
In one aspect, the casting jacket of the above-described system is formed as a cylinder, such that when the pre-casting assembly is received in the casting jacket, a first void bounded by the first forming plate and the casting jacket, a second void bounded by the second forming plate and the casting jacket, a third void at least partially bounded by the front wall and the casting jacket, and a fourth void bounded by the back wall and the casting jacket. The third void and fourth void may each be additionally bounded by the first and second forming plates.
In yet another aspect of the above-described system, the first pipe aperture defines a first pipe flow axis and the second pipe aperture defines a second pipe flow axis, the first and second pipe flow axes defining a first angle that is acute or obtuse as viewed through the entry aperture; the front wall has a first angled profile corresponding to the first angle; and the back wall having a second angled profile corresponding to a reflex angle explementary to the first angle.
In still another aspect of the above-described system, the front wall is a solid wall with at least one vertical bend such that the solid wall defines a front wall angle commensurate with the first angle of the first and second pipe flow axes. Alternatively, the front wall may be a hinged wall including a plurality of segments with a first segment, a last segment, and at least one intermediate segment between the first segment and the last segment, the plurality of segments hingedly connected to one another about a vertical axis. The first angle may be formed between the first segment and the last segment.
In a further aspect, the above-described system may further include at least one support plate sized to be received in a void formed between an inner surface of the casting jacket and the hinged front wall, the support plate having a curved wall-contacting surface which maintains a correspondingly curved profile of the front hinged wall during formation of the concrete base.
In a still further aspect, the above-described system may further include a plurality of piano-style hinges hingedly connecting respective pairs of the plurality of segments, each piano-style hinge having a hinge pin portion substantially flush with adjacent inner surfaces of a neighboring pair of the plurality of segments.
In a further aspect of the above-described system, the back wall may be a hinged wall comprising a plurality of segments including a first segment, a last segment, and at least one intermediate segment between the first segment and the last segment, the plurality of segments hingedly connected to one another about a vertical axis. The reflex angle may be formed between the a first segment and the last segment. The system may further include a plurality of piano-style hinges hingedly connecting respective pairs of the plurality of segments, each piano-style hinge having a hinge pin portion substantially flush with adjacent inner surfaces of a neighboring pair of the plurality of segments. The system may also further include a plurality of segments each defining a segment width W sized to correspond to an incremental angle A for a given radius R defined by the back wall, such that
wherein the plurality of segments are assembled to create a total reflex angle equal to n*A, where n is the number of the plurality of segments. The incremental angle A may be 6 degrees and the radius R may be between 36 and 48 inches. The non-cylindrical peripheral boundary of the pre-casting assembly may be sized to be received in the cylindrical casting jacket having an 86-inch diameter.
In another aspect of the above-described system, the plurality of reinforcement rods are disposed between the liner and the non-cylindrical peripheral boundary of the pre-casting assembly.
In another aspect, the above-described system includes a header having an outer periphery corresponding to the non-cylindrical peripheral boundary of the pre-casting assembly and an inner periphery sized to be received over the entry aperture of the liner to form an annular pour gap between the inner periphery of the header and an adjacent outer surface of the entry aperture. The header may be vertically adjustable to a desired height within the non-cylindrical peripheral boundary of the pre-casting assembly. A pour cover may be received over the entry aperture such that a base of the pour cover blocks access to the entry aperture from above but is spaced away from the inner periphery of the header, the pour cover defining a peak above the base and a tapered surface extending from the peak to the base whereby cement can flow from the peak into the pre-casting assembly via the annular pour gap to produce the concrete base. The pour cover may be conical.
In another aspect, the above-described system includes a support structure received within the liner to provide mechanical support for the liner during formation of the concrete base. The support structure may be an inflatable liner support including a flow channel support sized to be received in the flow channel of the liner and an entry aperture support sized to be received in the entry aperture. The support structure may include at least one expansion band disposed in the entry aperture.
In yet another form thereof, the present disclosure provides a method of forming a manhole base including a liner with a pair of pipe apertures and an entry aperture accessing a flow channel, a concrete base at least partially surrounding the liner, and a plurality of gaskets, the method including: assembling aperture supports to each of the pipe apertures, the aperture supports substantially filling the pipe apertures; assembling a first forming plate to a first one of the aperture supports; assembling a second forming plate to a second one of the aperture supports; assembling a back wall to a back portion of the first forming plate and a back portion of the second forming plate, such that the back wall extends partially around the liner from the first forming plate to the second forming plate; and assembling a front wall to a front portion of the first forming plate and a front portion of the second forming plate, such that the front wall extends partially around the liner from the first forming plate to the second forming plate, wherein the steps of assembling the first forming plate, the second forming plate, the back wall and the front wall and the liner form a pre-casting assembly in which a non-cylindrical peripheral boundary is formed around the liner with the entry aperture forming an open upper end of the pre-casting assembly.
In one aspect, the above-described method includes lowering the pre-casting assembly into a casting jacket, such that the first and second forming plates engage an inner wall of the casting jacket. The casting jacket may be cylindrical, such that the step of lowering the pre-casting assembly into the casting jacket creates a first void bounded by the first forming plate and the casting jacket, a second void bounded by the second forming plate and the casting jacket, a third void bounded by the first forming plate, the casting jacket, and the front wall, and a fourth void bounded by the first forming plate, the casting jacket, and the back wall.
In another aspect, the above-described method may include assembling a plurality of reinforcement rods to the liner. The step of assembling a plurality of reinforcement rods may include forming a mesh or cage of reinforcement rods at least partially around the liner.
In yet another aspect, the above-described method may include selecting at least one geometrical characteristic of the liner, the geometrical characteristic comprising at least one of: an angle between first and second pipe flow axes of the pair of pipe apertures respectively; an elevation of at least one of the pair of pipe apertures; and a diameter of at least one of the pair of pipe apertures.
In yet another aspect, the above-described method may include pouring concrete inside the non-cylindrical peripheral boundary of the pre-casting assembly, the concrete capable of setting to become a concrete base at least partially surrounding the liner. The step of pouring concrete may include embedding the anchoring portion of the liner in the concrete. The method may further include unfolding the gasket from its folded configuration after the concrete base is formed.
In still another aspect of the above-described method, the step of assembling a back wall includes: assembling a plurality of wall segments to one another such that the wall segments define a curved profile defining a radius; and choosing the number of wall segments to define the overall angle defined by the back wall.
In another aspect of the above-described method, the step of assembling a front wall includes: assembling a plurality of wall segments to one another such that the wall segments define a curved profile defining a radius; and choosing the number of wall segments to define the overall angle defined by the back wall.
In still another aspect, the above-described method includes joining the first forming plate to the second forming plate by a tie rod extending through the flow channel.
In still another aspect, the above-described method includes assembling a header to the pre-casting assembly near the entry aperture of the liner, such a pour gap is formed between an inner periphery of the header and an adjacent outer surface of the entry aperture. The method may further include pouring concrete through the pour gap. The step of assembling the header may include vertically adjusting the header to a desired height within the non-cylindrical peripheral boundary of the pre-casting assembly. The method may further include trimming the entry aperture portion of the liner using the header as a cut guide. The method may still further include lowering a pour cover over the entry aperture, the pour cover blocking access to the entry aperture but allowing access to the pour gap.
In yet another aspect, the above-described method includes assembling an inflatable liner support in the liner such that a flow channel support is received in the flow channel of the liner and an entry aperture support is received in the entry aperture of the liner.
In still another aspect, the above-described method includes further comprising assembling at least one expansion band in the entry aperture.
In still another aspect, the above-described method further includes: assembling a gasket to each of the aperture supports, such that an anchoring portion of the gasket is disposed adjacent the liner and a sealing portion of the gasket is folded inwardly between the anchoring portion and the aperture support; placing the first forming plate into abutment with the anchoring portion of the adjacent gasket during the step of assembling a first forming plate to a first one of the aperture supports; and placing the second forming plate into abutment with the anchoring portion of the adjacent gasket during the step of assembling a second forming plate to a second one of the aperture supports.
In yet another form thereof, the present disclosure provides a liner form assembly including: a cup-shaped entry aperture support having a base plate and a substantially cylindrical collar plate fixed to the base plate; a plurality of components sized to be received upon the base plate opposite the collar plate, the plurality of components shaped to collectively define an arcuate flow path having a flow path diameter and a flow path angle; and at least two pipe aperture supports sized to align with and abut end components of the plurality of components, the pipe aperture supports and the plurality of components fixed to one another.
Any combination of the aforementioned features may be utilized in accordance with the present disclosure.
The above-mentioned and other features and advantages of this disclosure, and the manner of attaining them, will become more apparent and the invention itself will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings. These above-mentioned and other features of the invention may be used in any combination or permutation.
Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrates are exemplary embodiments of the invention, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.
The present disclosure provides a durable, compact and relatively lightweight manhole base assembly 10, shown in
The present disclosure also provides manhole form assembly 100, shown in
Various features of manhole base assembly 10 and associated structures and methods for making the same, including manhole form assembly 100 and liner form assembly 200, are described below. The embodiments disclosed below are not intended to be exhaustive or limit the invention to the precise forms disclosed in the following detailed description. Rather, the embodiment is chosen and described so that others skilled in the art may utilize its teachings. Moreover, it is appreciated that a manhole base assembly made in accordance with the present disclosure may include or be produced by any one of the following features or any combination of the following features, and may exclude any number of the following features as required or desired for a particular application.
Liner 12 may be a monolithic polymer or plastic component uniform in cross section and made from a suitable polymeric materials such as polyethylene, high density polyethylene (HDPE), acrylonitrile butadiene styrene (ABS) plastics, and other thermoset engineered resins. In another embodiment, liner 12 may be a composite polymer or plastic component including a smooth inner surface layer, such as a polymer inner layer chosen for resistance to hydrogen sulfide, bonded to a strong outer structural layer, such as fiberglass. Such a liner 12 may be formed from fiberglass sprayed over a removable core, such as liner form assembly 200 as described in detail below. In another embodiment, liner 12 is a molded component, such as an injection or rotationally molded component which may have a substantially uniform thickness TL throughout its profile. Generally speaking, the thickness TL for a given liner material is set to provide sufficient strength to withstand the expected loads encountered during the concrete casting process (described further below) and/or during service in a piping system, with an appropriate margin of safety.
In one exemplary embodiment, liner 12 is formed from high-strength polymer or fiberglass material having thickness TL between ⅛ inch and ½ inch depending on the overall size of manhole base 10, it being understood that an increase in size is associated with an increase in expected load during production and service of manhole base assembly 10. Exemplary high-strength polymer materials are available from Mirteq, Inc. of Fort Wayne, Ind. and described in, e.g., U.S. Pat. No. 8,153,200 and U.S. Patent Application Publication Nos. 2012/0225975, 2013/0130016 and 2014/0309333. In some instances, such high-strength polymer materials may be used as a coating or covering over a substrate formed from another polymer.
In another exemplary embodiment, liner 12 is formed from fiberglass and has thickness TL between ¼ inch and ¾ inch, again depending on the overall size of manhole base 10. Another exemplary material for liner 12 may include polyvinyl chloride (PVC) having thickness TL of about ¼ inch, which may be molded or vacuum formed into the illustrated configuration. Still other exemplary materials for liner 12 include polyethylene, high density polyethylene (HDPE), acrylonitrile butadiene styrene (ABS) plastics, and other thermoset engineered resins. In certain exemplary embodiments, the material of liner 12 may be chosen based on compatibility with the material of pipes 50 and/or 54. For example, where pipes 50 and/or 54 are formed from a polymer material such as HDPE, PVC or polypropylene, the material for liner 12 may be chosen to provide corresponding service characteristics such as longevity, fluid flow performance characteristics, resistance to chemical attack, etc.
Liner 12 may also be formed from multiple constituent components which are molded or otherwise formed separately and then joined to one another to form the final liner 12. In one embodiment, for example, the aperture portion 26A of liner 12 is formed from an appropriately-sized rectangular strip or sheet which is folded into a cylindrical shape (see, e.g.,
Liner 12 includes first pipe aperture 20 and second pipe aperture 22 defining a flow channel 24 passing through liner 12 between apertures 20 and 22. Entry aperture 26 is disposed at the top portion of liner 12, above first and second pipe apertures 20 and 22, and descends into the cavity of liner 12 in fluid communication with flow channel 24. As best seen in
Turning to
Turning back to
Side walls 64, 66 are positioned radially outward from the outer diameter of entry aperture portion 26A, as illustrated in
Liner 12 also includes a generally tubular, substantially cylindrical entry aperture portion 26A defining longitudinal axis 27, as illustrated in
As discussed herein, benching structures 32 and 34 may be monolithically formed together with the other portions of liner 12 as a single unit. In the above-described alternative embodiments with entry aperture portion 26A and the remainder of liner 12 formed as separate components, benching structures 32 and 34 may also be formed as separate structures. In particular, each bench 32, 34 may be formed as a sheet or plank which is interposed between the cylindrical entry aperture portion 26A and the remainder of liner 12, then affixed to both structures by, e.g., welding. In some embodiments, the sheet used for benching structures 32, 34 may protrude outwardly past the cylindrical outer surface of entry aperture 26A and into the surrounding concrete base 14 in order to provide additional fixation of liner 12 to base 14.
In an exemplary embodiment, diameter DE of entry aperture portion 26A is designed to be only slightly larger than diameter DP of first and second pipe apertures 20, 22. As described in detail below, the size differential between diameters DE and DP can be expressed by the ratio DE:DP. This ratio is maintained at a nominal value greater than 1 in order to allow passage of structures through entry aperture portion 26A and into pipe apertures 20, 22, such as pipe aperture plugs, vacuum testing plugs or other maintenance equipment as may be needed. However, maintaining the DE:DP ratio close to 1 also minimizes the overall size of liner 12, as well as facilitating reduced concrete use in the finished manhole base assembly 10.
For example, in one particular exemplary embodiment, diameter DE of entry aperture portion 26A may be set at a maximum of 6 inches larger than diameter DP of pipe apertures 20, 22. Across a typical range of aperture sizes, such as between 24 and 60 inches for diameter DP and between 30 and 66 inches for diameter DE, this size constraint results in the DE:DP ratio ranging between 1.1 and 1.25. This ratio is sufficiently close to 1 to ensure that the overall footprint and concrete usage for manhole base assembly 10 is kept to a minimum, thereby increasing its overall production efficiency and field adaptability. In a typical field installation, for example, diameter DP of pipe apertures 20, 22 may be determined by the parameters of the larger system interfacing with manhole base assembly 10, e.g., minimum flow requirements of a sewage system. In such applications, industry standard pipe diameters DP may be as little as 24 inches, 30 inches or 36 inches and as large as 42 inches, 48 inches or 60 inches, or may be within any range defined by any pair of the foregoing values. By setting diameter DE at 6 inches larger than diameter DP, diameter DE is as little as 30 inches, 36 inches or 42 inches and as large as 48 inches, 54 inches or 66 inches, or may be within any range defined by any pair of the foregoing values. Because diameter DE is only slightly larger than diameter DP, the overall footprint and material usage needed for manhole base assembly 10 may be substantially lower than existing designs for a given pipe aperture diameter DP, while still meeting or exceeding the fluid flow rates and fluid flow characteristics required for a particular application.
Turning now to
Turning again to
Referring to
Advantageously, this non-cylindrical overall outer profile cooperates with the corresponding profile of liner 12 to provide a low variability among the various thicknesses TB of base 14, as illustrated in
If all thicknesses TB are taken in the aggregate throughout the volume of base 14, an average thickness of base 14 may be calculated. In an exemplary embodiment which minimizes the use of excess concrete for base 14 by implementing the illustrated non-cylindrical overall profile, any discrete thickness TB can be expected to vary from the average base thickness by no more than 100%. Stated another way, a thickness TB taken at any point in the volume of base 14 is less than double but more than half of the average thickness. In this way, base 14 defines an overall thickness with low variability throughout its volume.
At this point it should be noted that, in some embodiments, base 14 may include certain external features which are not part of the relevant volume of the non-cylindrical overall outer profile. For example, as illustrated in
As shown in
When concrete is poured into pre-casting assembly 102 to form manhole base assembly 10, as shown in
In an exemplary embodiment, reinforcement rods 18 are made of rebar formed into a steel cage which at least partially surrounds liner 12, leaving openings for entry aperture 26 and pipe apertures 20, 22 as shown in
In an exemplary embodiment shown in
In its finished condition shown in
With bottom rebar assembly 268 fixed to liner 12, entry aperture rebar assembly 270 may be lowered over entry aperture portion 26A and affixed to bottom rebar subassembly 268 (e.g., by welding) and to liner 12 by bolting to anchor 262 via washers 274. Similarly, pipe aperture rebar subassemblies 272 may be passed over aperture supports 108 and secured to bottom rebar subassembly 268 and/or entry aperture rebar subassembly 270 (e.g., by welding). In the illustrated embodiment of
In particular, reinforcement assembly 366 includes bottom panel 368, sidewall panels 372A and 372B, front panel 371, back panel 373 and top panel 370, each of which is sized and configured to be installed to liner 12 adjacent bottom, side, front, back and top walls 68, 64, 66, 60, 62 and 69 of liner 12 respectively. Reinforcement assembly 366 further includes a cylindrical cage 369 sized to be received over liner 12 and within the outer periphery collectively defined by panels 368, 370, 371, 372A, 372B, 373. Cage 369 and panels 368, 370, 371, 372A, 372B, 373 may each be fixed to liner 12 via anchors 262, in similar fashion to subassemblies 268, 270, 272 described above, e.g., anchor washers 274 may be welded to wires, rods or rebar struts 367 at appropriate locations to interface with anchors 262. Panels 368, 370, 371, 372A, 372B, 373 and cage 369 are also fixed to one another at their respective junctions, such as via welding or wire ties.
In the illustrated embodiment, panels 368, 370, 371, 372A, 372B, 373 and central cage 369 are each formed as a mesh of wires or rods 367 extending horizontally and vertically and woven or otherwise engaged at regular crossing points 367A to create a network of gaps of a predetermined size. Respective abutting wires 367 may be welded at each such crossing point 367A. The gaps have a horizontal/lateral extent defined by the spacing between neighboring vertical wires 367, and a vertical extent defined by the spacing between neighboring pairs of horizontal wires 367, as illustrated in
Turning to
In an exemplary embodiment, wedge 276 may be made of styrofoam material which can be formed into any desired shape or size as required for a particular application. Alternatively, wedge 276 may be made from an inflatable structure having seams and/or internal baffles to impart the desired shape and size.
Upon formation of concrete base 14, gaskets 16 are partially cast into the material of concrete base 14. Turning to
Extending axially outwardly from the outer surface of anchoring section 36 is sealing section 38, which includes an accordion-type bellows 38A for flexibility and a sealing band coupling portion 38B with a pair of recesses sized to receive sealing bands 40. This arrangement allows for pipe 50 to be undersized with respect to aperture 20, defining gap G therebetween when pipe 50 is received within pipe aperture 20 as illustrated in
In alternative embodiments, gaskets 16 may not be cast in to the material of concrete base 14, but simply disposed between the inner surfaces of aperture portions 20A, 22A and the adjacent outer surfaces of pipes 50, 54 respectively with an interference fit in order to form a fluid-tight seal. One exemplary seal useable in this way is the Kwik Seal manhole connector available from Press-Seal Gasket Corporation of Fort Wayne, Ind. In yet another alternative, gaskets 16 may be secured to the inner surface of pipe aperture portions 20A, 22A without being cast in to the concrete material. Exemplary expansion-band type products useable for sealing the inner surface in this manner include the PSX: Direct Drive and PSX: Nylo-Drive products, available from Press-Seal Gasket Corporation of Fort Wayne, Ind.
Turning now to
As best seen in
Turning now to
In order to assemble liner form assembly 200, the cup-shaped entry aperture support 202 is positioned with its opening facing down as shown in
As best seen in
Assembly 200 also includes end components 218 and 220. As best seen in
As noted above, each of components 218, 220, 222, 224, and 226 define either a wedge-shaped cross-section or a straight-walled, generally rectangular cross-section. In the aggregate, the wedge-shaped and straight-walled components cooperate to impart a curvature to liner form assembly 200 corresponding to the desired curvature of flow channel 24 (
However, any arrangement and configuration of such wedge shapes may be provided to produce any desired angles α and Θ around any desired flow radius R (
In other arrangements, such as the alternative design shown in
Still other changes may be made to respective components 218, 220, 222, 224, and/or 226 in order to affect the overall geometry and function of flow path 24. For example, the overall height of components 218, 220, 222, 224, and/or 226 may be gradually increased or reduced along flow path 24 in order to create, for example, a vertical grade along the flow path through liner 12. This vertical grade may be used to create a drop from the intake side of pipe apertures 20, 22 to the outlet side thereof. In an exemplary embodiment, this drop may be set to a drop of 1-inch per 100 inches of flow path extent, though any drop may be created by simply altering the respective heights of components 218, 220, 222, 224, and/or 226.
As best seen in, e.g.,
Turning again to
At this point, tie cable 242 may be passed through pipe aperture supports 230 (
In one exemplary embodiment, liner form assembly 200 may include sealing tape 227 placed over each junction between adjacent neighboring components 218, 220, 222, 224 and 226, as shown in
Turning to
As best seen in
With sheets 250, 252, 254, and rings 256, 258 in place, each sheet may interconnected with adjacent sheets by, e.g., adhesive or welding. In this way, sheets 250, 252, 254 and rings 256, 258 cooperate to form a base layer of liner 12. In an exemplary embodiment, the inner surfaces of the respective sheets may be smooth to facilitates fluid flow through liner 12, while the outer surfaces thereof include anchors 260 as noted above. In an exemplary embodiment, sheets 250, 252, 254 and rings 256 and 258 are made from a polymer material, such as a polymer chosen for resistance to hydrogen sulfide (H2S) gas in order to facilitate long-term high performance in sewage system applications.
With sheets 250, 252, 254, and rings 256, 258 assembled and interconnected to form the inner layer of liner 12, fiberglass may be sprayed over the assembly of sheets to form the outer layer of liner 12. This fiberglass material may then be smoothed and cured in a traditional manner. During the spraying process, liner/rebar anchors 262 (
In another alternative, sheets 250, 252, 254 and/or rings 256, 258 may be applied to the outside surface of liner 12 after formation and curing. In this instance, liner 12 may have three layers including a smooth inner layer (made from, e.g., a polymer material “painted” over liner form assembly 200 as described above), a structural intermediate layer (e.g., a fiberglass material sprayed and cured as described above), and an outer layer adhered or otherwise affixed to the intermediate layer formed of sheets 250, 252, 254 and/or rings 256, 258. This outer layer may provide additional strength and rigidity benefits, while also providing anchors 260 for fixation of liner 12 to concrete base 14 as described herein.
After the layer of fiberglass is cured, liner 12 is fully formed and liner form assembly 200 may be removed. In particular, pipe aperture supports 230 may be withdrawn from the now-formed pipe apertures 20, 22 (
Next, center component 226 and intermediate components 222 may be removed from flow channel 24 of liner 12 via entry aperture 26 of the newly formed liner 12. With center and intermediate components 226, 222 removed, intermediate component shims 225 may be pried away and removed through entry aperture 26, at which point truncated intermediate components 224 may also be removed by tilting component 224, passing it into the center of flow channel 24 withdrawing it through entry aperture 26. Finally, end component shims 219 may be pried away and end components 218 and 220 may be removed by pushing inwardly from pipe apertures 20, 22 respectively to pass end components 218, 220 toward the center of flow channel 24, and then withdrawing end components 218, 220 through entry aperture 26. At this point, liner form assembly 200 is fully withdrawn, such that liner 12 can be used in the production of manhole base assembly 10 as described in detail below.
Prior to assembly of pre-casting assembly 102, aperture support assemblies 106 are prepared as shown in
Aperture support assembly 106 is then mounted to first pipe aperture 20, as illustrated in
In one exemplary embodiment, aperture support assemblies 106 are simply press-fit into apertures 20 and 22. However, in some instances, it may be desirable to affix aperture support assemblies 106 in their assembled positions to ensure their proper positioning with respect to liner 12 throughout the casting process.
In addition, the fluid pressure within inflatable support 170 provides mechanical reinforcing support for liner 12 to avoid bending or buckling of the polymer material of liner 12 during the casting process. In the illustrated embodiment, inflatable liner support 170 includes air valve 178. Liner support 170 may be placed and arranged within liner 12 in a deflated configuration, and then inflated via air valve 178 to the configuration shown in
An alternative option for fixation of aperture support assemblies 106 to liner 12 is illustrated in
Turning again to
Hinged back wall assembly 126 is assembled to aperture support assemblies 106 in similar fashion to solid front wall 116. However, as shown in
As best seen in
With segments 130, 132 and 134 hingedly connected, back wall 126 forms a generally arcuate profile defining radius R, as shown in
Referring still to
where radius R is assumed to be the arc inscribed within the multifaceted arcuate profile formed by back wall 126. If radius R is assumed to be circumscribed around this multifaceted arcuate profile, incremental angle A can be expressed in terms of width W and radius R as
As a practical matter, where A is small (e.g., 6 degrees as noted herein), taking R as circumscribed around or inscribed within the multifaceted arcuate profile of back wall 126 does not make a significant difference.
The number n of segments 130, 132 and 134 can be chosen such that the total angle traversed by back wall 126 is equal to n*A, or the number of segments multiplied by the incremental angle A defined by each segment. In an exemplary embodiment, A is equal to about 6°, such that back wall 126 can be modularly assembled to sweep through any desired angle divisible by 6. Thus, in the illustrated embodiment in which obtuse angle α is 120 degrees, the number N of segments 130, 132 and 134 is 120/6, or 20 segments.
Referring to
In some embodiments, a front wall (e.g., solid wall 116 or assembly 128) may not be needed at all. For example, for some configurations of manhole base assembly 10, front wall 70 of concrete base 14 may be formed against the interior of casting jacket 104 without a separate front wall provided in pre-casting assembly 102.
With aperture support assemblies 106 assembled to liner 12 and front and back walls 116, 126 assembled to support assemblies 106, the basic form of pre-casting assembly 102 is complete. Pre-casting assembly 102 can then be lowered into casting jacket 104 as a single unit in preparation for the introduction of mixed flowable concrete to form concrete base 14. Alternatively, aperture support assemblies 106 and liner 12 can be lowered into casting jacket 104 prior to assembly of front and back walls 116, 126, which can be individually lowered into casting jacket 104 to complete pre-casting assembly 102 within the cylindrical cavity of casting jacket 104.
When pre-casting assembly 102 is received within the cylindrical casting jacket 104 as shown in
Header 154 may also be included to form an upper barrier for the flow of concrete into the cavity formed by pre-casting assembly 102, corresponding with top wall 80 of concrete base 14 after the pour operation is complete. The lower barrier, corresponding with bottom wall 78 of concrete base 14, is a closed bottom end of casting jacket 104. As best seen in
In an alternative embodiment, forming plates 110, 120 and/or front and back walls 116, 126 can formed as wedge-shaped structures sized to substantially completely fill one of voids 140, 142, 144 or 146. For example, forming plate 110 may be a wedge shape with a flat inner surface and a curved, arcuate outer surface shaped to engage the adjacent inner surface of casting jacket 104. In this configuration, the wedge-shaped forming plate 110 can provide consistent mechanical support for formation of concrete base 14 with a reduced tendency to bend or bow under pressure. Such wedge-shaped structures may be formed in a similar fashion to concrete displacement wedge 276.
Pour cover 160 may be lowered through collar 166 of header 154 and seated upon entry aperture portion 26A to close entry aperture 26, as shown in
As concrete pours into pre-casting assembly 102, the void within pre-casting assembly 102 begins to fill. Concrete is prevented from flowing into the interior of liner 12 by aperture support assemblies 106 at pipe apertures 20, 22, and by pour cover 160 at entry aperture 26 as noted above. Thus, during the period when the concrete in pre-casting assembly 102 remains flowable (i.e., before the concrete sets), liner 12 becomes buoyant. In order to maintain liner 12 in the desired position, anchor bar 48 shown in
Accordingly, manhole base assembly 10 can be cast in a “right side up” configuration. After concrete base 14 has set following the pour operation, manhole base assembly 10 may be withdrawn from casting jacket 104 in the orientation in which it is intended to be installed for service. Advantageously, there is no need for manhole base assembly 10 to be rotated or inverted from an “upside-down” configuration to a “right side up” configuration after the casting operation is completed as with many known casting regimes, as such rotation/inversion may be a difficult operation in some circumstances due to the weight of manhole base assembly 10.
It is also contemplated that pre-casting assembly 102 can be lowered into casting jacket 104 in an “upside-down” or inverted configuration, in which entry aperture 26 opens downwardly toward the closed lower end of casting jacket 104. In this case, concrete may be poured directly into the void of pre-casting assembly 102 over bottom wall 68 of liner 12 (
Turning now to
As noted above with respect to
Referring still to
Any number of expansion band assemblies 180 may be used to support entry aperture portion 26A, depending on its overall axial length and the amount of mechanical support required. Where an entry aperture portion 26A is desired to be shorter than its as-molded condition after production of liner 12, excess material may be trimmed away. In an exemplary embodiment, header 154 may be placed at a desired height, and inner collar 166 may then serve as a cutting guide for entry aperture portion 26A.
When it is desired to form a manhole base assembly 10 with a first angle α and reflex angle Θ different from the illustrated 120-degree configuration, an alternative liner 12 is first produced or obtained with the desired geometry. As noted above, many of the components used in creating liner forming assembly 200 can be used to create other, alternative geometries including various angles α and Θ. Moreover, similar parts and varying arrangements of such parts can be used to form any desired liner configuration.
Advantageously, many of the same components used for pre-casting assembly 102 as described above can again be used in a reconfigured pre-casting assembly 102 compatible with the alternative geometry. For example, a number of intermediate segments 134 may be added to or removed from hinged back wall assembly 126 and hinged front wall assembly 128 in order to accommodate the alternative angular arrangement. Aperture support assemblies 106 may still be used in conjunction with such reconfigured back and front wall assemblies 126, 128. Where the size of first pipe aperture 20 and/or second pipe aperture 22 is changed, only aperture supports 108 of aperture support assemblies 106 (
Moreover, the various components of pre-casting assembly 102 can be configured in a variety of ways for compatibility with a chosen geometry of liner 12, and all of these configurations may be receivable within the same industry-standard casting jacket 104, such as a cylindrical jacket having an 86 inch inside diameter. This allows established casting operations to utilize standard casting jackets 104 and other tooling, while still realizing the benefits of reduced concrete consumption, modular geometry and cast-in gaskets as described above.
In the illustrated embodiment, manhole base assembly 10 may be sized and configured to be used in lieu of a traditional 86-inch diameter cylindrical concrete base assembly. Thus, casting jacket 104 with an 86-inch diameter may be originally designed to produce, e.g., a 72-inch cylindrical manhole base with a 7-inch thick wall. ASTM 478 and ASTM C76, the entire disclosures of which are hereby incorporated herein by reference, specify relevant concrete wall thicknesses for pipes and manholes.
Referring to
However, it is contemplated that manhole base 10 may be produced in a variety of sizes and configurations to be used in lieu of a corresponding variety of standard cylindrical manhole bases, or in custom sizes. For example, manhole base assembly 10 may be sized for use with pipes 50, 54 having inside diameters ranging from 18 inches to 120 inches. Similarly, manhole base assembly 10 may be sized for use with risers 58 having an inner diameter between 24 inches and 140 inches. In particular exemplary embodiments of the type illustrated in the figures, pipes 50, 54 may have inside diameters between 18 inches and 60 inches, with risers 58 having inside diameters between 30 inches and 120 inches.
Moreover, the non-cylindrical outside profile of manhole base assembly 10 and corresponding reduction in concrete use for concrete base 14 cooperates with the design of liner 12 to enable some flexibility and modularity in the use and implementation of base assembly 10. For example, more than one size and of liner 12 can be used in conjunction with a single size of form 100. A particular size of liner 12 may be chosen based on the sizes and configuration of pipes 50 and 54. The chosen size and one or two other neighboring liner size options may all fit within a given form 100, with the only difference among liner sizes being the thickness of concrete base 14 and associated differences in affected structures (e.g., rods 18 and associated spacers, anchors, etc.). Moreover, provided that entry aperture 26A (which is sized to match a particular riser 58) and the overall outer profile of concrete base 14 are compatible with a chosen form 100, any size and configuration of liner 12 can be used in form 100.
In addition, the non-cylindrical outer profile of manhole base assembly 10 enables assembly 10 to carry large volumes of fluid through fluid channel 24 while occupying a smaller overall footprint than a traditional cylindrical manhole base assembly. This smaller footprint may in turn enable the use with smaller riser structures (e.g., risers 58 and other riser structures) for a given fluid capacity, thereby enabling cost savings.
While this disclosure has been described as having exemplary designs, the present disclosure can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the disclosure using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this disclosure pertains and which fall within the limits of the appended claims.
This application claims the benefit under Title 35, U.S.C. §119(e) of U.S. Provisional Patent Application Ser. No. 62/082,391, filed on Nov. 20, 2014 and entitled MANHOLE BASE ASSEMBLY WITH INTERNAL LINER AND METHOD OF MANUFACTURING SAME, the entire disclosure of which is hereby expressly incorporated by reference herein.
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