AU2009222579B2

AU2009222579B2 - Method of lining a utilities manhole

Info

Publication number: AU2009222579B2
Application number: AU2009222579A
Authority: AU
Inventors: Craig Hamilton Mcrobert
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-10-02
Filing date: 2009-10-02
Publication date: 2016-08-04
Anticipated expiration: 2029-10-02
Also published as: AU2009222579A1

Abstract

A method of lining a manhole comprises pre-fabricating an insert 30 provided with one or more channels 32 which correspond with channels 24 of a bench 20 5 of the manhole; installing a first sleeve 34 in the manhole to cover a length of the peripheral walls 10; and, attaching the insert 30 to the first sleeve 34 in an orientation where the corresponding channels 32 provide a path between conduits 14, 16 and 18 which feed into the bench 20.

Description

METHOD OF LINING A UTILITIES MANHOLE

Field of the Invention

The present invention relates to a method of lining a utilities manhole, such as, but not limited to, a manhole for a sewer.

Background of the Invention A manhole to allow access for the servicing of an underground utility may comprise a hole formed in the ground which is often lined by concrete or bricks and is provided with a cover at ground level. Conduits or pipes lead to and from a base of the manhole. The conduits may carry fluids such as water or sewerage; or, cables and pipelines.

In time, the lining of the manhole deteriorates and may require repair and refurbishment. This is particularly the case for sewerage manholes where gases produced by sewerage, most notably, hydrogen sulphide corrode concrete, brick or other masonry linings and other components in the manhole.

Summary of the Invention

One aspect of the present invention provides a method of lining a manhole having an access opening, and a peripheral wall extending from the access opening to the one or more channels, one or more channels providing communication to one or more conduits extending to the manhole, the method comprising: pre-fabricating an insert provided with one or more corresponding channels that correspond to the one or more channels of the manhole; installing a first sleeve into the manhole to cover a length of the peripheral wall extending from a location near the one or more conduits toward the access opening; and, attaching the insert to the first sleeve such that the one or more corresponding channels line or completely replace the one or more channels of the manhole, and in an orientation where the one or more corresponding channels provide a path between the conduits, wherein pre-fabricating the insert comprises forming a side wall of a dimension to fit through the first sleeve and attaching the one or more corresponding channels to the side wall.

In one embodiment pre-fabricating the insert comprises constructing a template which provides respective indications of the location of the conduits.

Pre-fabricating the insert may comprise using the template to construct the one or more corresponding channels in a configuration to extend between the respective indications locations of the conduits.

The method may comprise installing respective spigots in the conduits prior to installing the first sleeve in the manhole.

The method may comprise forming each spigot to fit inside a respective conduit and providing each spigot with a radially extending flange at a location intermediate the length of the spigot.

Constructing the template may comprise placing a template support in the manhole near the spigots, locating guide plates having cut-outs to seat on the spigots, and attaching the guide plates to the template support.

Attaching the insert to the first sleeve may comprise attaching the spigots to the corresponding channels.

Attaching the insert to the first sleeve may comprise attaching the side wall of the insert to an inside surface of the first sleeve.

The method may comprise fabricating the first sleeve to comprise a base plate at an end near the conduits when the first sleeve is installed in the manhole, the base plate being configured to have an outer peripheral region which abuts the peripheral wall of the manhole and a hole about which the sleeve is attached to the base plate.

The method may comprise providing the outer peripheral region of the base plate with a flexible skirt which flexes upwardly as the first sleeve is installed in the manhole.

The method may comprise, prior to insertion of the insert, at least partially removing a bench of the manhole in which the one or more channels are formed to form a void in the manhole.

In an alternate embodiment the method may further comprise covering the one or more channels with a plate prior to insertion of the first sleeve.

Covering the one or more channels may comprise levelling the plate to lie in a substantially horizontal plane.

The alternate embodiment may further comprise seating the first sleeve on, and sealing the first sleeve to, the plate. Thereafter a hole is cut in the plate to allow access to the one or more channels.

Attaching the insert may comprise seating the insert in the void and orientating the insert to align corresponding channels with the conduits.

The method may further comprise coupling the conduits to the corresponding channels.

In both embodiments the method may further comprise dimensioning the first sleeve in a manner to create a space between an outside surface of the first sleeve and the peripheral wall, and backfilling the space. Backfilling the space may comprise pouring a settable material into the space.

Embodiments of the method may further comprise filling regions between the one or more corresponding channels of the insert and a bottom of the manhole with a material. This may further comprise filling the regions with a settable material.

Embodiments of the method may further comprise lining a surface of the filled regions with a liner made from a gas impervious material.

Embodiments of the method may further comprise providing the first sleeve with one or more anchors on an outer peripheral surface of the first sleeve.

The method may further comprise installing one or more additional sleeves in the manhole in end-to-end abutment and sealingly coupling abutting ends of the first sleeve and the one or more additional sleeves together. A second aspect of the present invention provides a method of lining a manhole having an access opening, a base and a peripheral wall extending from the access opening to the base, the method comprising: pre-fabricating an insert configured to extend across and at least partially overlay the base; installing a first sleeve in the manhole to line a length of the peripheral wall between the base and the access opening; and, attaching the insert to an end of the sleeve adjacent the base.

This aspect may further comprise lining regions of the base not overlaid by the insert with a gas impervious material.

Brief Description of the Drawings

Embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings in which:

Figure 1a is a section view of a bottom portion of a manhole to be repaired by application of embodiments of the present method;

Figure 1 b is a top elevation view of the manhole shown in Figure 1 a but with a sleeve and insert placed in the manhole;

Figure 2 is a cross-sectional view of the manhole shown in Figures 1a and 1b showing an outside surface of the sleeve;

Figure 3a is a cross-sectional view of the manhole shown in Figure 2 in which an embodiment of an insert used in a method is depicted being delivered to a bench of the manhole;

Figure 3b is a schematic representation of one form of the insert;

Figure 4 is a cross-sectional view of the manhole shown in Figure 3a depicting the insert being attached to the sleeve;

Figure 5 is a cross-sectional view of the manhole shown in Figure 4 depicting attachment of the insert to conduits feeding to and from the manhole;

Figure 6 is a cross-sectional view of the manhole shown in Figure 5 depicting backfilling of the insert;

Figure 7 is a representation of a manhole in which a sleeve and insert have been fitted prior to backfilling of the insert;

Figure 8 is a representation of a lower portion of the manhole in which an insert has been fitted, backfilled and lined;

Figure 9 is a cross-sectional view of a manhole which has been lined in accordance with a second embodiment of the present method;

Figure 10 is a representation of an insert incorporated in the method;

Figure 11 is a representation of a sleeve used in a further embodiment of the method;

Figure 12 is a representation of a base plate which forms part of the sleeve shown in Figure 11;

Figure 13 is an enlargement of a portion of the base plate shown in Figure 12;

Figure 14 is a representation of a template that may be used in embodiments of the method; and,

Figure 15 is a representation of a guide plate which forms part of the template shown in Figure 14.

Detailed Description of Preferred Embodiments

Embodiments of the present method of lining a utilities manhole may enable the manhole to be repaired or refurbished in a manner which reduces the amount of time a worker is required to be located within the manhole in comparison with methods where benches and channels in the manhole are repaired and relined in situ. This is accomplished by pre-fabricating an insert which is used to: (at least partially) replace a bench of the manhole; or, reline the bench. As the insert is pre-fabricated, it can be assembled outside of the manhole and installed in the manhole when required.

Figure 1a depicts a lower portion of the manhole having a peripheral side wall 10 extending upright from a manufactured (ie, concrete) base 12. Conduits 14, 16 and 18 communicate with a bench 20 formed between the walls 10 and the base 12. The bench 20 often has a generally concave upper surface 22 and one or more channels that provide communication between the conduits 14, 16 and 18. The concave upper surface 22 assists in draining liquid toward the channels 24 in the event of flooding. In the illustrated manhole, the peripheral wall 10 is of a square profile. The wall 10 and bench 20 are typically made from concrete. When the manhole is a sewerage manhole, the concrete is corroded by hydrogen sulphide gas produced by the sewerage. Additionally, methane is produced by the sewerage. The hydrogen sulphide and methane also create a dangerous environment for people working within the manhole.

In broad terms, one form of the method of lining a manhole comprises prefabricating an insert 30 (see Figures 3a and 3b) provided with one or more corresponding channels 32 (these channels corresponding with the channels 24 of the bench 20); installing a first sleeve 34 in the manhole to cover a length of the peripheral walls 10 extending from the bench 20 toward an access opening of the manhole; and, attaching the insert 30 to the first sleeve 34 in an orientation where the corresponding channels 32 provide a path between the conduits 14,16 and 18. By pre-fabricating insert 30, the amount of time required for people to be physically located within the manhole in order to effect its lining is likely to be reduced. The insert 30 may comprise a circumferential ring 36 made of a plastics material such as PVC. A number of circular holes 38 are formed in the ring 36 at locations corresponding to the conduits 14, 16 and 18. The channels 32 extend between the holes 38 and are configured to correspond with the channels 24 and the bench 20. The channels 32 are typically also made from PVC.

The insert 30 is dimensioned so that it can fit within the sleeve 34. When lining the manhole, initially a base plate 40 is lowered into the manhole to overlie the bench 20. The base plate 40 is shaped and dimensioned so as to fit within the peripheral wall 10 with minimal clearance. Depending on the state of the bench 20, packing or support material may be required to level the base plate 40 so that it sits substantially horizontally. Once the base plate 40 is in place and has been levelled, the first sleeve 34 is lowered into the manhole. The sleeve 34 may be made from PVC of a wall thickness of approximately 10mm or more. The first sleeve 34 is dimensioned so as to fit within the peripheral wall 10 with a degree of clearance about its outer circumferential surface thereby leaving a space 44 between the inside of the peripheral wall 10 and the outer surface of the sleeve 34. In the illustrated embodiment, the sleeve 34 has a circular transverse section.

The sleeve 34 is lowered into the manhole and seated on the base plate 40. A hole 46 of a diameter marginally smaller than an inner diameter of the sleeve 34 is cut in the base plate 40. This forms an inner ledge 48 on which the sleeve 34 sits. The inside surface of the sleeve 34 is welded or glued to the ledge 48. Once the sleeve 34 has been attached and sealed to the base plate 40, any overhanging portions of the ledge 48 can then be removed, maximising the diameter of the hole 46.

Depending on the state of the bench 20, it may be completely or partially removed by use of known concrete breaking and/or cutting machines including, for example, a jackhammer. Figure 3a depicts a manhole in which the bench has been completely removed and where the insert 30 is shown being lowered into the manhole through the sleeve 34. The insert 30 is lowered to a position and orientated so that the corresponding channels 30 form a path between the conduits 14, 16 and 18. The corresponding channels 32 either line or completely replace the channels 24 of the original bench 20 (depending on the degree of removal of the original bench 20).

The space 44, at least up to a position close to an upper end of the sleeve 34, is backfilled. A suitable backfilling material such as concrete may be used. The backfilled space is defined between an upper surface of the base plate 40, inner surface of the peripheral walls 10 and outer surface of the sleeve 34.

During the backfilling process, one or more supports (not shown) may be lowered into the sleeve 34 to hold the sleeve 34 in its original shape, counteracting any pressure that may be applied or exerted by the backfilling material in a radial inward direction on the sleeve 34. Ideally, support may be expandable and collapsible support. In this way the support can be lowered into the sleeve 34 in a collapsed state and subsequently reconfigured to an expanded or erected state in which it braces the sleeve 34 to resist any deformation that may otherwise be caused by pressure exerted by the backfilling material.

Following the backfilling of the space 44, and the insertion and appropriate orientation of the insert 30, the insert 30 is welded 35 or otherwise attached to the sleeve 34 as shown in Figure 4.

With reference to Figures 5 and 10, pipe spigots 50 are inserted in the conduits 14, 16 and 18. In this embodiment the spigots are inserted after installation of the insert 30, but in an alternate embodiment described later the spigots are inserted into the conduits prior to the installation of the insert 30. Each spigot comprises a first portion 70 of a diameter to fit inside a respective conduit 14, 16, 1 and a second contiguous portion 72 of a diameter to seat in the corresponding channel 32. These diameters may be the same or different. A flange 74 extends radially about the spigot 50 at a location where the two portions meet. The first portion 70 of the spigots is inserted into a respective conduit 14, 16, 18, up to the flange 74, with the second portion 72 of the spigots seated in the corresponding channels 32. The spigots are then attached, for example by welding, gluing or otherwise to the conduits and the corresponding channels 32.

Figure 7 depicts an inside of a manhole in which the bench has been removed and an insert 30 and sleeve 34 installed. The channels 32 of the insert 30 are clearly visible. A void 52 between the channels 32 and ring 36 of the insert 30 and removed portions of the bench is backfilled to rebuild the bench. Cementitious materials such as concrete, or other settable materials may be used for the backfill. The backfilling material may be poured and shaped to again form a generally concave surface 53 (see Figures 5 and 6) or otherwise profile or contoured surface so as to direct liquid to flow into the channels 32. Thus, generally, speaking, the backfilling material is at a higher level adjacent the inside surface of the sleeve 34 and relieving or sinking toward the edges of the channels 32. A lining 51 (see Figure 8) made from a gas impervious material such as PVC strips or sheets can be embedded in the settable material prior to its setting and welded, glued or otherwise attached to the inside surface of the channels 32. This provides an impervious layer between any gases such as hydrogen sulphide that may be present in the manhole from contacting the cementitious material. The lining 51 may conveniently comprise a relatively narrow strip that is cut by scissors or a knife and laid in an overlapping fashion to cover the required area.

Depending on the depth of the manhole, one or more additional sleeves can be lowered into the manhole and attached in an end-to-end fashion to the first sleeve 34. To assist in the end-to-end attachment of adjacent sleeves 34, an exterior circular collar 56 (see Fig. 2) may be used to assist in attaching the adjacent sleeves 34 together. Further, to assist in anchoring of the sleeves 34 within the manhole, the sleeves may be provided with one or more anchors 58 on their outer circumferential surface. The anchors 58 may be formed, for example, of longitudinal ribs or flanges. A lid (not shown) made from plastics material or plastic lined concrete may be incorporated to close the upper end of the manhole. Alternately, metallic lids may be used.

If desired, the interior surface of each sleeve 34 may also be lined by the same impervious material used for the insert. This provides a further barrier between gases that may reside within the manhole and cementitious material used in the constructing of the peripheral wall 10, and in the backfilling material in the space 44.

Figure 9 depicts an alternate embodiment for lining manholes. This embodiment may be particularly useful for very deep manholes. In essence, the method depicted in Figure 9 differs from the method depicted in Figures 1-8 only by use of a single sleeve 34 which is provided with its own lid 60 at an end opposite the insert 30. By placing a lid 60 at an upper end of the sleeve 34, there is no need to install further inserts to line a remaining portion of the peripheral wall 10. A capped vent pipe 62 extends from the sleeve 34 through the lid 60 and to an upper lid of the manhole. The vent pipe 62 is provided with a valve at its upper end that can be selectively opened and closed to allow a sampling of gases within the sleeve 34. Thus the lid 60 in effect seals the manhole at a location at an upper end of the first sleeve 34. Apart from the installation of the lid 30 and the vent 62, the method of lining the manhole depicted in Figure 9 is the same as that explained above in relation to Figures 1-8. A further embodiment of the method will now be described with reference to Figures 10 to 15.

In this embodiment, initially the bend 20 is completely removed. The first portion 70 of each spigot 50 is then inserted into the conduits 14, 16, 18 up to the flange 74. A first sleeve 34 as shown in Fig. 11 is installed in the manhole to a location near the conduits and spigots 50. The first sleeve 34a differs from the sleeve 34 described above in that it is fabricated with a base plate 40a (see also Figs. 12 and 13) prior to being installed in the manhole, and is generally of a shorter length, such as for example 500mm. The sleeve 34a is provided with longitudinal anchors 58 on its outer circumferential surface. Also a collar 56 is provided at the end of the sleeve 34a opposite the base plate 40a to facilitate joining to a further sleeve.

The base plate 40a is similar to the plate 40 and has a hole 46 but differs by the provision of a flexible skirt 78 which extends about the outer peripheral region of the plate 40a. The base plate 40a is also formed with a short upright collar 80 about the hole 46. The sleeve is seated in and attached to the collar 80, thereby attaching the sleeve 34a to the base plate 40a.

When the sleeve 34a is inserted in the manhole the skirt 78 abuts the side walls 10 and flexes upwardly. This assists in creating a seal against the side walls 10. The sleeve 34a is grouted in place by pouring cementitious material between the outside of the sleeve 34a and the side walls 10, with the upwardly flexed skirt 78 preventing the leakage below the base plate 40a. A template 82, shown in a constructed form in Fig. 14 is fabricated in the manhole to provide a guide in the fabrication of the insert 30. The template 82 comprises a template support in the form of a ring 84 and a plurality of guide plates 86. The ring 84 is lowered into the sleeve 34a to a location just above the spigots 50 and temporarily held in place. The guide plates are formed with cut outs 88 configured to seat on the spigots 50. The guide plates are placed with their cut out 88 sitting on a respective spigot 50, adjacent the ring 84, and subsequently attached to the ring 84 thereby constructing the template 82.

The template 82 is removed from the manhole and used to construct the insert 30. The template 82 is inverted and the ring 36 of the insert formed about the template. The cut outs 88 of the guide plates 86 denote the location of the spigots 50 (and indeed the conduits 14, 16, 18). Holes 38 are formed in the ring 36 at the locations of the cut outs 88. Next the corresponding channels 32 is constructed to run between the holes 38. By configuring the corresponding channel 32 to run between the holes 38 the corresponding channel will align with each of the spigots 50 and provide a flow path between the conduits 14, 16, 18.

The insert 30 is lowered into the manhole and inside of the sleeve 34a is orientated so that the second portion 72 of the spigots 50 seat in the corresponding channels 32. The spigots are attached to the corresponding channels and the ring 36 of the insert 30 attached to the inside of the sleeve 34a. The void between the corresponding channels 32, the underside of the base plate 40a and the bottom of the manhole is grouted as per the first described embodiment. Similarly further sleeves may be attached end to end to the sleeve 34a, and gas impervious linings may be applied as per the first described embodiment.

Now that embodiments of the invention have been described in detail it will be obvious to persons or ordinary skill in the art that numerous modifications and variations may be made without departing from the basic inventive concepts. For example the insert 30 and sleeve 34, as well as the lining are described as being made from PVC. However other materials such as HDPE, ABS, polypropylene or fibreglass may be used. Such modification and variations together with others that would be obvious to a person of ordinary skill in the art are deemed to be within the scope of the present invention the nature of which is to be determined from the above description and the appended claims.

Claims

The Claims Defining the Invention are as Follows:

1. A method of lining or refurbishing a manhole having an access opening, and a peripheral wall extending from the access opening to one or more channels, the one or more channels providing communication to one or more conduits extending to the manhole, the method comprising: pre-fabricating an insert provided with one or more corresponding channels that correspond to the one or more channels of the manhole; installing a first sleeve into the manhole to cover a length of the peripheral wall extending from a location near the one or more conduits toward the access opening; and, attaching the insert to the first sleeve such that the one or more corresponding channels line or completely replace the one or more channels of the manhole and in an orientation where the one or more corresponding channels provide a path between the conduits; wherein pre-fabricating the insert comprises forming a side wall of a dimension to fit through the first sleeve and attaching the one or more corresponding channels to the side wall.
2. The method according to claim 1 wherein pre-fabricating the insert comprises constructing a template which provides respective indications of the location of the conduits.
3. The method according to claim 2 wherein pre-fabricating the insert comprises using the template to construct the one or more corresponding channels in a configuration to extend between the respective indications locations of the conduits.
4. The method according to any one of claims 1 to 3 comprising installing respective spigots in the conduits prior to installing the first sleeve in the manhole.
5. The method according to claim 4 comprising forming each spigot to fit inside a respective conduit and providing each spigot with a radially extending flange at a location intermediate the length of the spigot.
6. The method according to claim 4 or 5 when dependant on claim 2 or 3 wherein constructing the template comprises placing a template support in the manhole near the spigots, locating guide plates having cut-outs to seat on the spigots, and attaching the guide plates to the template support.
7. The method according to any one of claims 4 to 6 wherein attaching the insert to the first sleeve comprises attaching the spigots to the corresponding channels.
8. The method according to any one of claims 4 to 7 wherein attaching the insert to the first sleeve comprises attaching the side wall of the insert to an inside surface of the first sleeve. 9 The method according to any one of claims 1 to 8 comprising fabricating the first sleeve to comprise a base plate at an end near the conduits when the first sleeve is installed in the manhole, the base plate being configured to have an outer peripheral region which abuts the peripheral wall of the manhole and a hole about which the sleeve is attached to the base plate. 10 The method according to claim 9 comprising providing the outer peripheral region of the base plate with a flexible skirt which flexes upwardly as the first sleeve is installed in the manhole.
11. The method according to any one of claims 1 to 10, comprising, prior to insertion of the insert, at least partially removing a bench of the manhole in which the one or more channels are formed to form a void in the manhole.
12. The method according to any one of claims 1 to 11, comprising configuring the first sleeve in a manner to create a space between an outside surface of the first sleeve and the peripheral wall, and backfilling the space.
13. The method according to claim 12, wherein backfilling the space comprises pouring a settable material into the space.
14. The method according to any one of claims 1 to 13, comprising filling regions between the one or more corresponding channels of the insert and a bottom of the manhole with a material.
15. The method according to claim 14, wherein filling the regions comprises filling the regions with a settable material.
16. The method according to claim 14 or 15, comprising lining a surface of the filled regions with a liner made from a gas impervious material.
17. The method according to any one of claims 1 to 16, comprising providing the first sleeve with one or more anchors on an outer peripheral surface of the first sleeve.
18. The method according to any one of claims 1 to 17, comprising installing one or more additional sleeves in the manhole in end-to-end abutment and sealingly coupling adjacent ends of the first sleeve and the one or more additional sleeves together.