Abstract: A cover for an underground enclosure may include an upper surface comprising a pattern of bosses, a first slot and a second slot disposed on the upper surface, a lower surface opposite the upper surface. A first reinforcement member may be coupled to the lower surface. The first slot may extend into the first reinforcement member, and a second reinforcement member may be coupled to the lower surface and aligned with the first reinforcement member. The second slot may extend into the second reinforcement member. The cover may be configured to be lifted by the first slot and the second slot.

Abstract: The use of a self-driving vehicle to automatically find manholes, and for each remove the manhole cover from the manhole, and thereafter put the manhole cover back in position on the manhole. In some embodiments, while the manhole cover is removed, the self-driving vehicle is used to automatically place a tool above or within the manhole. Accordingly, a self-driving vehicle can automatically inspect, repair, or maintain manholes that are positioned in roadways. The data can then automatically be gathered without human intervention.

Abstract: A drain assembly comprises a shroud, a shank, and a frame. The drain assembly may further comprise a shim with an angled top surface. The frame may have an angled bottom surface. A rotational orientation of the angled top surface of the shim relative to the shank and a rotational orientation of the angled bottom surface of the frame relative to the shank may be independently adjustable, thereby allowing for the top surface of the frame to be both angularly and rotationally adjusted relative to a central axis of the drain assembly independent of the positional height of the shank. The drain assembly may further comprise a cover having bendable tabs. The bendable tabs may be disposed around a periphery of the cover and may be configured to contact an angled inner surface of an upper bowl of the shroud, such that the bendable tabs bend around the frame, thereby locking the cover onto the frame.

Abstract: A system for use with a manhole vault having an internal atmosphere, and, optionally, with a ventilation stack connecting the vault to an external atmosphere. The system includes a manhole cover, a ventilation pipe, and an air moving assembly. The cover has one or more through-holes extending between top and bottom surfaces. Each of the through-hole(s) is in fluid communication with the external atmosphere at the top surface. The pipe has a through-channel that extends between first and second openings. The first opening is positioned proximal to either an opening into the ventilation stack or at least one of the through-hole(s) at the bottom surface of the cover. The second opening is positioned in the interior of the vault. The device is configured to cause a portion of one of the interior and external atmospheres to flow through the through-channel toward a different one of the interior and external atmospheres.

Abstract: Precast utility enclosure aprons for buried utility enclosures that have an angled top surface to direct water, ice and debris away from the center of the apron and to limit damage to the apron and utility enclosure caused by impacts to the apron.

Abstract: A manhole cover assembly comprises a base frame, the base frame comprising a base body and a base flange extending laterally outward from the base body. The assembly further comprises a top frame, the top frame comprising a top body disposed annularly about at least a portion of the base body, a top flange extending laterally outward from the top body, and a lip extending laterally inward from the top body.

Abstract: Disclosed is a simulator for training in environments confined and/or suspected pollution consists of a container having a base, a roof opposite the base, and short perimeter walls and long with at least one vertical manhole, a horizontal manhole and two safety exits to the outside. The two long perimeter walls delimit a plurality of internal compartments for the exercise of the personnel with equipment that create effects for the training activity, and at least one training activity control, command and management cabin with operator present. The internal compartments for the personnel training are at least partially separated by way of movable walls disposed transversely to the two long perimetral walls. The movable walls have adjustable passage openings through sliding partitions.

Abstract: A system and method are disclosed for sealing an annular manhole riser ring assembly. A generally flat, bendable liner includes a flat strip that is generally conformably engageable with an interior circumferential surface of the riser ring assembly. An outer surface of the liner strip carries a plurality of spacer elements that form a void between the generally flat liner strip and the engaged inner circumferential surface of the riser ring assembly. An expandable tensioning device is operated to press the riser ring assembly against the circumferential surface of the riser ring assembly. A flexible bonding substance is introduced into the void and allowed to set to seal the riser ring assembly.

Abstract: The invention refers to a lighting automatic system for pedestrian crossing and to a method of making the markings for the pedestrian crossings. The system comprises several lighting units sank in the asphalt made of a box (2)welded by a netting (11) fixed on the bottom of the hole made for the mounting of the lighting units, the box (2) having an external frame (5) and being closed with a detachable cap (4) equipped with a window in which a protection frame is fixed (6) of a piece made of safety glass (8), the cap representing the transversal marking of the pedestrian crossing, in the interior of the box (2) being a LED lighting unit (1) powered by a net or a photovoltaic plant (14) mounted on a pile (17) in the proximity of the pedestrian crossing, on the surface of the cap (4) being poured bitumen subsequently painted with reflecting painting, so that the glass (8) in the mounted state of the system, to be at the level of the roadway (10).

Abstract: The present invention relates to a spacer for a prefabricated spiral staircase, which allows adjustment of a height of a gap between footboards for a prefabricated spiral staircase in multiple steps by using minimal disks, and a prefabricated spiral staircase using the same. The spacer for a prefabricated spiral staircase comprises a cylindrical pipe, a lower cap or upper cap, a disk, a height adjustment member, and a location determining member, wherein the height of the spacer is adjusted in multiple stages according to relative rotation between the upper cap and the disk or between the lower cap and the disk.

Abstract: A manhole cover assembly comprises a base frame, the base frame comprising a base body and a base flange extending laterally outward from the base body. The assembly further comprises a top frame, the top frame comprising a top body disposed annularly about at least a portion of the base body, a top flange extending laterally outward from the top body, and a lip extending laterally inward from the top body.

Abstract: A manhole cover assembly has an inner cylinder and an outer cylinder. An upper ratchet mechanism extends axially and circumferentially about an outwardly facing surface of the inner cylinder. A lower ratchet mechanism extends axially and circumferentially about an inwardly facing surface of the outer. The lower ratchet mechanism is configured to mesh with the upper ratchet mechanism at one of a plurality of distinct ratcheting positions. A cover plate is disposed on one of the inner cylinder and the outer cylinder. The cover plate is at a first elevation when the lower ratchet mechanism meshes with the upper ratchet mechanism at a first distinct ratcheting position. The cover plate is at a second elevation when the lower ratchet mechanism meshes with the upper ratchet mechanism at a second distinct ratcheting position. The first elevation is different from the second elevation.

Abstract: A method for fabricating a laminated composite work piece includes providing a first layer of carbon fiber. The first layer extends continuously across the entire area of the work piece. A second layer is placed adjacent to the first layer. The second layer includes a first fiber material extending across a first portion of the work piece, and a second fiber material extending across a second portion of the work piece. The work piece is cured and provides a case component of an information handling system.

Abstract: A kit of materials to make a support for one or more manhole rings during a concrete pour around a prefabricated grease interceptor includes a base, a plurality of vertical supports, and a peripheral grid to surround a top of the prefabricated grease interceptor at a position to support a manhole seating ring. The vertical supports are long enough that they extend from the base to the peripheral grid for most grease interceptor installations or can be cut to size to position the peripheral grid.

Abstract: A controlled pressure release vault panel assembly is capable of functioning as a second, or auxiliary, relief port to allow the escape of fluid from the vault in the event of pressure build-up inside the vault or in an explosion event. The vault panel assembly may define an opening that includes a manhole cover assembly. The manhole cover assembly may also be vented, and may function as a primary vent. The vault panel assembly may include a retention assembly extending from the vault panel underneath a portion of the vault, enabling a limited range of motion of the vault panel for the escape of fluid and allowing the reseating of the vault pane on the vault once the pressure inside the vault approaches ambient pressures.

Abstract: A manhole riser extension assembly including separate upper and lower spacer rings which are assembled utilizing tabs that extend downwardly from the upper spacer ring about the lower spacer ring, and locking elements in association with the lower ring that cooperatively engage and bear radially outwardly against the tabs, respectively, to urge and/or lock the tabs against an inner surface of the manhole frame bounding the manhole cover seat, or to penetrate the tabs and bear against the inner surface, to hold the assembly together and in place in the manhole frame, and such that a manhole cover is positionable in sitting relation on the lower spacer ring, bounded by the upper spacer ring for covering the manhole. Optional lift protections tabs can be provided at locations about the upper spacer ring, in position to be covered by paving material to supplement the holding of the assembly in place.

Abstract: Incrementally extendable telescopic mounting, the extension of which is determined by a guide lug, integral with a female element and moving inside a multi-segment cam-type guide system, laid out at the periphery of a male element, and by the relative positions of a single cylindrical arc shaped stop having a trapezoid cross-section and being laid out on one of the telescopic elements, the trapezoid perimeter bearing surface of said stop resting successively on a circumferential series of staged cylindrical arc shaped hollow stops laid out on the other telescopic element and preferably having the same angular length, the same radial depth and the same trapezoid perimeter and area as those of the single stop, said single and multiple staged cylindrical arc shaped hollow stops having preferably, within their respective telescopic elements, the same outer and inner diameters and, as their common center, the device axis.

Abstract: A system and method are provided for coupling a manhole cover to an underground utility box to support the manhole cover substantially flush with a ground surface such as a roadway. A holder couples to an underground utility box and includes upper and lower ends and a channel extending therebetween, and a support structure extending into the channel and defining an upwardly facing support surface. An adjustment member for coupling to a manhole cover is inserted within the channel, and includes upper and lower ends, and a passageway extending therebetween and communicating with the channel. The adjustment member is movably receivable within the channel to be seated on the support surface, and to define an adjustment space between the adjustment member and the holder. The adjustment member may thus be adjusted for accommodating a slope and elevation of a ground surface, and sealed with the holder after adjustment.

Abstract: A portion of a street surface to be removed for access to a manhole cover is defined by placing a design mask on the street with a cutout overlying an electronic marker embedded in the street proximate the manhole. The design mask is oriented such that a larger cutout overlies the manhole cover, by aligning the design mask along an established direction. The design mask can be a template with a circular cutout, or a stencil with a ring cutout. When the marker is located proximate a curb line, the established direction may correspond to a normal from the curb line. A rectangular design mask can be oriented by keeping an edge of the design mask which is closest to a curb line parallel with the curb line. Alternatively, a compass heading may be used, and a pointer feature of the design mask can be aligned with the compass heading.

Abstract: A drainage channel includes a first sidewall provided with a first rail member extending along a longitudinal axis of the drainage channel. A second sidewall extends along the longitudinal axis of the drainage channel with the first and second sidewalls at least partially defining an interior area of the drainage channel. A first locking insert is at least partially positioned within a first rail opening of the first rail member, with the first locking insert including a first insert opening. Further examples include methods of making a drainage channel.

Abstract: A manhole cover adapter system comprises an adapter assembly having a central passage and a wing structure which enables the system is to be embedded between pavement layers during installation. The manhole cover adapter further comprises an expansion joint assembly and, if required, an angular adjustment assembly for allowing uses in various construction scenarios upon various types of manholes.

Abstract: A manhole riser extension assembly including separate upper and lower spacer rings which are assembled utilizing tabs that extend downwardly from the upper spacer ring about the lower spacer ring, and locking elements in association with the lower ring that cooperatively engage and bear radially outwardly against the tabs, respectively, to urge and/or lock the tabs against an inner surface of the manhole frame bounding the manhole cover seat, or to penetrate the tabs and bear against the inner surface, to hold the assembly together and in place in the manhole frame, and such that a manhole cover is positionable in sitting relation on the lower spacer ring, bounded by the upper spacer ring for covering the manhole. Optional lift protections tabs can be provided at locations about the upper spacer ring, in position to be covered by paving material to supplement the holding of the assembly in place.

Abstract: The invention disclosed is an adjustable support adapted to support an access hatch frame for access to a sub-surface chamber or the like. The support has a lower frame member that at least in part defines a first aperture, the first aperture having or defining a first plane, the lower frame member having at least one upper interface surface. A similar upper frame is present that defines a second aperture, a second plane, and a lower interface surface. Upper frame member also has number of height adjustable mount points. The upper and lower interface surfaces define an interface plane. Rotation of the upper frame member, relative to said lower frame member on the interface plane, adjusts the relative angle of the two.

Abstract: A support apparatus for a frame of a utility access cover comprises an inner support member and an outer support member in telescopic engagement with the inner support member. The height and inclination of the support apparatus is adjustable by selectively positioning the first support member relative to the second support member and securing the first support member to the second support member with the fasteners.

Abstract: Disclosed is an improved assembly for facilitating the elevated and leveled placement of a paver surface. Yet further disclosed are related methods of using the assembly.

Abstract: A manhole cover assembly configured to behave as a relief valve in an explosion event, opening so that fluid, such as air or explosive gas, may vent from an underground area. The manhole cover assembly may include a manhole cover and a frame, and may be configured to limit movement of the manhole cover with respect to the frame in response to increased pressure on the manhole cover. In one embodiment, the manhole cover may include legs having angled surfaces adapted to substantially center or guide the manhole cover in the frame while the manhole cover displaces to release pressure. In another embodiment, one or more legs slidable within the manhole cover to enable configuring the manhole cover between a restraint mode and a removal mode.

Abstract: A system and method are provided for coupling a manhole cover to an underground utility box to support the manhole cover substantially flush with a ground surface such as a roadway. A holder couples to an underground utility box and includes upper and lower ends and a channel extending therebetween, and a support structure extending into the channel and defining an upwardly facing support surface. An adjustment member for coupling to a manhole cover is inserted within the channel, and includes upper and lower ends, and a passageway extending therebetween and communicating with the channel. The adjustment member is movably receivable within the channel to be seated on the support surface, and to define an adjustment space between the adjustment member and the holder. The adjustment member may thus be adjusted for accommodating a slope and elevation of a ground surface, and sealed with the holder after adjustment.

Abstract: A system and method are provided for coupling a manhole cover to an underground utility box to support the manhole cover substantially flush with a ground surface such as a roadway. A holder couples to an underground utility box and includes upper and lower ends and a channel extending therebetween, and a support structure extending into the channel and defining an upwardly facing support surface. An adjustment member for coupling to a manhole cover is inserted within the channel, and includes upper and lower ends, and a passageway extending therebetween and communicating with the channel. The adjustment member is movably receivable within the channel to be seated on the support surface, and to define an adjustment space between the adjustment member and the holder. The adjustment member may thus be adjusted for accommodating a slope and elevation of a ground surface, and sealed with the holder after adjustment.

Abstract: A manhole cover which has an upper body and a lower body coupled to each other to maintain balance, to endure loads applied from an external source in a stable manner, to protect the inside of the manhole from the ingress of rainwater, and to enable the upper body to be stably fixed inside the lower body.

Abstract: A riser assembly and method for engaging the same to raise a manhole cover to be flush with an inclined paved surface after the application of an additional layer of paving material thereto. The riser assembly includes a first and second riser frame with a plurality of specially manufactured spacer blocks fixedly secured between them. The spacer blocks have progressively different height dimensions and sloped upper surfaces so as to create an angle between the first and second riser frames. The angle is complementary to the slope of the paved surface. The riser assembly includes an expansion device for adjusting the diameter of the second riser frame so that it frictionally engages the existing manhole frame. The fixed securement of the spacer blocks prevents relative movement between the first and second riser frames even when the diameter of the second riser frame is changed.

Abstract: A cable gland and gasket ring assembly includes a gasket ring and a cable gland formed of a shell, a collar, a packing ring and a connection ring for securing a cable, or, a cable and a flexible conduit, to a junction box. The gasket ring is an annular member, having a first end face, a second end face opposing the first end face, a plurality of annular ribs concentrically arranged on the first end face and an annular convex portion located on the second end face. The connection ring has a stop flange segment, a first connection ring segment extended from one side of the stop flange for holding the gasket ring, an outer thread located on the first connection ring segment for fastening to a junction box, a recessed portion on the stop flange segment for receiving the annular convex portion of the gasket ring and a tapered inner surface located on the inside of the stop flange segment for stopping against a tapered outside surface of the packing ring.

Abstract: An adjustable frame configured to receive a standard grate includes a plurality of threaded openings that may be threadably engaged with bolts to adjust an elevation of the frame. The threaded openings may be configured to have a desired thread pitch, which in turn dictates how much the frame may be lowered or raised with one full turn of the bolt. Optionally, threaded bushings may be installed into the frame to engage with the bolts.

Abstract: A multi-purpose adjustable quick expandable installment which can be quickly and finely adjusted and ascend or descend freely, by a snap design which adjusts ascending or descending with a slope principle, based on a mechanical principle that a force is constant if acting on a same area and an opposite force compensates with the force. Through a structure which follows the law of action and reaction to compensate with a sliding force which occurs naturally, a stable movement without moving accidentally is formed.

Abstract: A method for renovating a well curb by lifting it to a first position, whereafter a compressible device is positioned around the well curb. Hereafter the well curb is lowered to a second position so that the compressible device is abutting the upper edge of the well, whereafter a casting material is injected into the cavity between the surface dressing and a filling around the well. Finally the well curb is lowered to a third and final position. Also, a compressible device for use in the method.

Abstract: An apparatus for repairing an existing spill containment manhole operably associated with an underground fuel storage tank. The apparatus includes a containment vessel for containing fuel spilled during filling of the underground fuel storage tank. A major portion of the containment vessel is adapted to be inserted into an existing spill containment manhole. The containment vessel includes at least one wall that surrounds an existing pipe section operably associated with the underground fuel storage tank when the containment vessel is installed. The at least one wall has an inner surface and an outer surface. Preferably, the containment vessel includes an upper annular flange that extends over and surrounds a portion of an existing cover rim of an existing spill containment manhole thereby isolating an upper portion of the containment vessel from an upper portion on the existing spill containment manhole when the containment vessel is installed.

Abstract: A manhole includes a frame and plug, which moves backward relative to the frame, to ensure the plug reaches a proper closed position in the frame. A first end of a self-locking arm of the structure is pivotally mounted to the frame, and can slide in a fixed guiding groove. The first end of the arm bears on a fixed stop of the frame during tilting of the plug toward the closed position of the frame. The arm moves the plug backwards and so the plug correctly closes the opening of the frame.

Abstract: The specification discloses apparatus and a process in which the stack of concrete or hard rubber spacer rings used in raising manholes is eliminated. It is replaced with a sleeve which is taller than the required distance between the top of the manhole and the level at which the casting and manhole cover are to be finally located, but which is sufficiently flexible in a vertical direction that when a casting is located in the top of the sleeve, the sleeve compresses downwardly. The height of the casting is fixed by a casting support resting on the pavement base coat or other base surface to which the final pavement will be applied around the casting. The sleeve is sufficiently stiff in a lateral direction that it does not collapse inwardly when backfill is packed in and around the exterior of the sleeve. The casting support is removed and the final layer of pavement is applied over the base surface.

Abstract: A system and method are provided for coupling a manhole cover to an underground utility box to support the manhole cover substantially flush with a ground surface such as a roadway. A holder couples to an underground utility box and includes upper and lower ends and a channel extending therebetween, and a support structure extending into the channel and defining an upwardly facing support surface. An adjustment member for coupling to a manhole cover is inserted within the channel, and includes upper and lower ends, and a passageway extending therebetween and communicating with the channel. The adjustment member is movably receivable within the channel to be seated on the support surface, and to define an adjustment space between the adjustment member and the holder. The adjustment member may thus be adjusted for accommodating a slope and elevation of a ground surface, and sealed with the holder after adjustment.

Abstract: A quick, field installed sump cover system for below ground sumps includes a support ring, a seal between the ring and sump upper lip, preferably two compression brackets each having two spaced regions extending under riser parts, at least one elongated member coupled between the support ring and compression brackets for selectively applying tension forces therebetween causing the bracket regions to engage the riser parts and the support ring to compresses the sealing member to form liquid-tight seal with the sump lip. The sump top can be closed by a dome-cover removably coupled to the support ring. The elongated members can include chain-like members with tensioning devices that, in field installations, can accommodate various sump sizes.

Abstract: An underground structure cover comprises a cover body (10) and a receiving frame (20) arranged so that the cover body is fitted in and supported by the receiving frame in the manner that an inclined surface (11) of the outer circumference of the body meets an inclined surface (21) of the inner circumference of the frame. The inclined surfaces (11, 21) each have an upper inclined surface (11a, 21a) and a lower inclined surface (11b, 21b), and the lower inclined surfaces (11b, 21b) are steeper than the upper inclined surfaces (11a, 21a). The body (10) is fitted in and supported by the part (20) at the upper inclined surfaces (11a, 21a) and the lower inclined surfaces (11b, 21b). By this, the body is prevented from being wedged into the frame too deeply and also from becoming inclined with respect to the frame or riding up.

Abstract: This frame (2) comprises a bottom plate (22) which has a base (26) which defines a frame support surface (28) which is directed towards an inner side (I) and a skirt (20) which is intended to receive a covering element (4) and which defines an outer side (E). The bottom plate (22) comprises at least one cell (32) which is open towards the inner side (I). Use in frames for manholes.

Abstract: A manhole cover for preventing the inflow of a bad smell and a harmful insect is provided. More particularly, the manhole cover includes a manhole top plate that has a plurality of drainage holes and a display part; a drainage guide plate that is integrally formed in a bottom part of the manhole top plate; a gate that is provided in a front end exit of the drainage guide plate and that is closed by a weight; and walls that are vertically and integrally formed in four edges of the manhole top plate. The display part, which is provided in one side of the manhole top plate can perform a specific display such as a trademark, a firm name, a logo, a slogan. The gate can be fully opened or closed within a space part by forming the space part in a lower part of the display part.

Abstract: Depressed manhole covers affect vehicles negatively. The B-W Manhole Cover-Cover is a recycled rubber disc attached to the existing manhole cover with toggle-bolts. It will provide proper elevation.

Abstract: A manhole cover includes a support having an upper surface and a peripherally-extending portion. An outer insulating member is disposed over the entire upper surface of the support, and the support comprises a first material and the outer insulating member comprises a second material different from the first material. The peripherally-extending portion of the support is positionable over the lip of the manhole ring. The outer insulating member is positionable between the upper surface of the support and the upper surface of the rim of the manhole ring when the manhole cover is received in the manhole ring. In one aspect, the support comprises cross-members defining a grate having passageways through the support. In another aspect, the support comprises metal, and the outer insulating member comprises a composite of resin, reinforcement fibers, and stone aggregate. In another aspect, screen inserts are disposed in a plurality of passageways in the outer insulating member.

Abstract: Embodiments of the present invention relate to a cover for a manhole or similar structure that encapsulates a traditional cover so as to extend the height of the cover. Generally, a conventional manhole cover is partially or entirely encapsulated in polyurethane to change its outside dimensions to match the environment of an intended location.

Abstract: An apparatus and a method are provided for raising the elevation of a catch basin during reconstruction or repaving of roadways in order to raise the elevation of existing catch basin grills to that of the new elevation of the modified roadway. The improved catch basin riser utilizes a newly formed catch basin top and spacer that each define a height dimension approximately equal to an elevated roadway dimension. The catch basin top is fabricated from concrete reinforced with galvanized rebar and angle iron. In the field, the existing catch basin grill is removed exposing the grill ledge and a prefabricated spacer is positioned on the grill ledge. The new catch basin top is bonded to the existing catch basin top and the grill is positioned upon the spacer within the new catch basin top and the existing catch basin top at the new elevation of the modified roadway.

Abstract: Provided herein are covers useful for covering the open end of an access conduit that may contain fluid control equipment. In one embodiment, a cover according to the invention comprises a disc-shaped base portion having a top surface and a bottom surface, with a plurality of groups of stability tangs attached to its bottom surface. A cover as provided herein is readily adaptable to fit a large number of conduit boxes, valve boxes and the like which are presently in common use.

Abstract: An apparatus that automatically levels a manhole upon placement of the manhole in the road. The preferred embodiment includes a support beam, two clamping units and two carrying handles. The clamping units contact the top of the manhole and clamp the manhole to the bottom of the support beam. The carrying handles assist in placing the manhole in the road and aligning the support beam on top of the road. The road surface forces the bottom of the support beam to align with the road. Since the top of the manhole is clamped to the bottom of the support beam, the manhole is also forced to align with the new road surface. The present manhole leveler works on roads with steep inclines and banking.

Abstract: A manhole collar for mounting in a manhole is defined by a tube with rigid strips shaped to form lobes welded around the upper edge with a bottom edge of each lobe for engaging the ground or other surface around the manhole. A support sleeve is mounted on the tube in a recessed notch at an angular location thereon defining a cylindrical receptacle to hold a post standing up from the manhole for a davit or the like. The sleeve extends partly into the tube and partly outwardly and on the outside is supported by one of the lobes and on the inside by a planar chordal gusset plate. The sleeve includes a cylindrical bushing and a clamping pin for clamping the post in the sleeve engaging through a hole in the sleeve against an outer surface of the cylindrical bushing so that threaded adjustment of the pin causes an end of the pin to press against the cylindrical bushing and divert the bushing inwardly.

Abstract: A stackable polymeric foam adjustment or grade ring is provided for the construction of the adjustment courses or manhole chimney portion of a sewer system. The adjustment ring is circular and may include concentric annular grooves on at least one surface and male portions corresponding in size and shape to the concentric annular grooves on a second surface. The adjustment rings are stacked one on another with the respective male portions being coupled within a corresponding annular groove to provide a manhole construction that is resistant to inflow, chemicals and freeze-thaw cycle damage.