WO2009136367A1

WO2009136367A1 - A method of constructing a manhole in a road and a manhole plug

Info

Publication number: WO2009136367A1
Application number: PCT/IB2009/051850
Authority: WO
Inventors: David John Drake Hawkins
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-05-06
Filing date: 2009-05-06
Publication date: 2009-11-12
Anticipated expiration: 2010-11-06

Abstract

A method of constructing a manhole in a road (26) which involves the replacement of an existing manhole with a new manhole, includes providing a manhole plug (10) which is disc-shaped and which comprises a cast iron manhole frame (12) and a surrounding moulding (13) in which the frame is embedded. The existing manhole is removed by introducing a cutting tool into the manhole and making an annular undercut in the road under the existing manhole and thereafter, using a barrel cutter, making a cylindrical cut in a direction perpendicular to the road surface around the existing manhole to the depth of the undercut. The existing manhole and surrounding road material is then removed leaving behind a hole into which the manhole plug (10) is fitted.

Description

A METHOD OF CONSTRUCTING A MANHOLE IN A ROAD AND A

MANHOLE PLUG

FIELD OF INVENTION

The invention relates to a method of constructing a manhole in a road. It relates also to a manhole plug for use in the construction of a manhole in accordance with the method.

BACKGROUND TO INVENTION

It is well known to provide manholes, such as, for example, in road and pavement surfaces, for providing access to underground services and installations such as electrical, telephone, plumbing and sewerage services and installations. Typically, such manholes include cast metal manhole frames defining an internal passage, which are usually set in concrete or some other suitable material and which are positioned substantially flush with a road or pavement surface. Manhole covers are provided for such manhole frames and fit within the open upper end of the manhole frames so as to be substantially flush with the road or pavement surface. Below the manhole frame, access to underground services and installations, is provided by a service access structure, typically a pipe defining an access chamber, which terminates at its upper end in a cover plate onto which conventional brick work is built to provide a platform for the seating of the manhole frame thereby to position the manhole frame substantially flush with a road or pavement surface.

Over time such manholes need to be repaired or replaced altogether. To minimise traffic disruption, such repairs and new construction work is often carried out outside of normal working hours which is often more costly, creates disturbance as well as fatigue to workers and thus increases the possibility of poor work performance. Also, because of the disruption to traffic, time is of the essence. As the work needs to be carried out relevantly quickly, this often results in the contractor carrying out the work hastily in order to minimise disruption, leading again to poor workmanship. Furthermore, the bedding material used for road maintenance, typically comprises rapid curing materials which are considerably affected by moisture and temperature. As such, the prevailing weather significantly affects the consistent performance of the work carried out. A further problem is that when a maintenance crew arrives on site to repair a manhole, they have to carry with them all of the materials and tools required to complete any manhole repair job as the particular tools and materials required for the actual job will not be known prior to commencing work on the manhole construction. Yet a further problem associated conventional manhole construction methods and materials, is that the base layer under the wear surface of a road or pavement is typically of asphalt which is known to become compacted over a period of a few years. Thus, if asphalt is used in the repair of the surrounding road or pavement, it is likely to become compacted and as a result subside in relation to the surrounding material used in the construction of the manhole, leading to a likelihood of damage to the manhole.

It is an object of the present invention to provide a manhole construction, a method of constructing a manhole and a manhole plug which ameliorate the abovementioned problems and disadvantages.

Any reference hereinafter to a "road" must be interpreted sufficiently broadly to include a pavement, or the like.

SUMMARY OF INVENTION

According to the invention there is provided a method of constructing a manhole in a road, which includes:

providing a manhole plug of a predetermined shape and size, the manhole plug having an upper end and a lower end and defining a manhole passage which extends between and which is open at its upper and lower ends;

forming a hole in a road above a service access chamber which has previously been constructed below the road surface, the hole defining a longitudinal axis which is substantially perpendicular to the road surface, the hole being open at the road surface and extending downwards therefrom to a depth immediately above the cover plate of the access chamber, the hole having a shape which conforms generally to the shape of the manhole plug and which is slightly larger in size than the manhole plug, the hole having a width dimension at its lower end wherein said width of the hole is larger than the width of the access opening of the cover plate of the service access chamber; and

fitting the manhole plug into the hole, thereby constructing a manhole in the road.

The method may include forming the hole in the road by:

cutting into the road in a longitudinal direction which is substantially perpendicular to the road surface, thereby to define the sides of the hole; and

removing any material surrounded by the longitudinal cut thereby to form the hole in the road.

The method may include making said longitudinal cut in the road using a core cutting rig having a rotary cutting barrel which is operable to make a cylindrical cut into the road material. The method may include locating an adhesive between the cover plate of the service access structure and a part of the underside of the manhole plug which rests on the cover plate, for bonding the manhole plug to the cover plate.

The method may include introducing a flowable, settable filler material into the gap between the sides of the hole and the side wall of the manhole plug. The filler material may have adhesive properties which permits it to form a bond between the hole and the manhole plug.

In a particular embodiment of the invention, the method may include positioning one or more spacer elements between the cover plate of the service access structure and the manhole plug thereby to raise the upper surface of the manhole plug to a height where it is substantially flush with the surrounding road surface.

In a particular embodiment wherein the method of constructing a manhole is adapted for use in replacing an existing manhole in a road with a new manhole, the method may include forming said hole in the road around the manhole to be replaced and removing the manhole and any road material surrounded by the longitudinal cut to form the hole in the road.

More specifically, the method may include forming the hole by additionally cutting into the road from within the internal passage of the manhole to be replaced at said predetermined depth in a transverse direction relative to the longitudinal axis of the hole, thereby to undercut the road material below the hole; and removing the manhole and any road material surrounded by the longitudinal and transverse cuts.

In another embodiment wherein the method of constructing a manhole is adapted for use in constructing a new manhole in a new section of road, the method may include constructing the new section of road over a service access chamber; locating the position of the service access chamber below the road surface of the new section of the road; forming said hole in the road directly above the service access chamber; and fitting the manhole plug into the hole thereby to provide a manhole which provides access to the service access chamber.

The invention extends to the manhole plug as defined and described hereinabove. The manhole plug may be in the form of a moulding which defines said upper and lower ends and said manhole passage.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features of the invention are described hereinafter by way a non-limiting example of the invention, with reference to and as illustrated in the accompanying diagrammatic drawings. In the drawings: Figure 1 shows a schematic perspective view of a manhole cover and a manhole plug in accordance with the invention, for use in the construction of a manhole, in accordance with the invention;

Figure 2 shows a schematic top plan view of the manhole plug of Figure 1 ;

Figure 3 shows a schematic side view of an existing manhole in a road which is to be replaced as part of a method of constructing a new manhole in the road, in accordance with the invention;

Figures 4a - d, show schematically, in sequence, the manner in which the existing manhole shown in Figure 3 is undercut as a step in the method of constructing a manhole in accordance with invention;

Figures 5a - c, show schematically, in sequence, the manner in which a cylindrical cut is made in the road to the depth of the undercut, around the existing manhole to be replaced;

Figure 6 shows the manhole to be replaced, being lifted from the road;

Figure 7 shows a schematic sectional side view of the manhole plug of Figure 1 in accordance with the invention, sectioned along section line VII - VII of Figure 2, fitted into the hole left behind by the removal of the manhole; Figure 8 shows a schematic cutaway perspective view of the manhole plug of Figure 1 fitted into the hole left behind after the removal of the replaced manhole; and

Figure 9 shows a schematic perspective view of another embodiment of a manhole plug in accordance with the invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

With reference to the drawings, a manhole plug for use in the construction of a manhole, in accordance with the invention, is designated generally by the reference numeral 10. The manhole plug 10 is disc-shaped and comprises a cast iron manhole frame 12 and a surrounding moulding 13 in which the manhole frame 12 is embedded.

The manhole frame 12 is of cast iron and has an upper end 14 and a lower end 16 and defines an internal passage 20 which extends between its upper and lower ends. A manhole cover 22 is fitted into the open upper end of the manhole frame 12 to close off the opening at its upper end.

The moulding 13 is of a polyurethane material which is bonded to and which surrounds the manhole frame 12 between its upper and lower ends. More specifically, the moulding 13 is moulded around the manhole frame so as to provide the manhole plug with its disc shape and specific dimensions. The manhole plug 13 is used in the construction of new manholes in new sections of road and also for replacing existing manholes in existing roads as will be explained in more detail hereinafter.

With reference to Figure 3 of the drawings, a prior art conventional manhole construction is illustrated wherein a conventional cast iron manhole frame 24 is constructed in a road 26 so that its upper surface is flush with the surface of the road. Below the manhole frame 24, a service access structure typically in the form of a pipe 28, is provided which defines an elongate access chamber 30 and which terminates in a cover plate 32 onto which conventional bricks 33 are built to provide a platform for the seating of the manhole frame 24 thereby to position the upper end of the manhole frame substantially flush with the road surface.

In a method of constructing a manhole in a road which comprises replacing an existing manhole in the road with a new manhole, in accordance with the invention, the method includes cutting away the road 26 around the existing manhole; removing the existing manhole frame 24 and surrounding road material; and fitting the manhole plug 10 into the hole left behind after the removal of the manhole frame and the surrounding road material.

With reference to Figures 4 a - d of the drawings, the hole is formed in the road 26 above the service access pipe 28 by, firstly, using a first cutting tool 34 having a rotary cutting disc, which is introduced from above into the internal passage 20 of the existing manhole frame 24 and at a depth immediately above the cover plate 32 of the service access structure 28, cutting into the road in a transverse direction relative to a longitudinal axis "A" defined by the manhole, thereby to undercut the road material below the manhole frame 24. The cutting disc of the cutting tool 34 is moved along an annular cutting path thereby to make an annular undercut below the manhole frame 24 which extends into the road material a predetermined distance outwardly beyond the manhole frame. Thereafter, with reference to Figures 5 a - c of the drawings, a core cutting rig having a rotary cutting barrel 36 is positioned adjacent the manhole frame 24 in the road. The rotary cutting barrel is lowered towards the road (as shown in Figure 5a), making a cylindrical cut in the road in a longitudinal directional which is perpendicular to the road surface (as shown in Figure 5b), around the existing manhole frame 24 to the depth of the undercut under the manhole frame. The rotary cutting barrel 36 is thereafter raised and removed (as shown in Figure 5c).

The longitudinal cut is thus made in the road around the existing manhole frame 24, until it intersects the undercut made by the first cutting tool. With reference to Figure 6, the manhole frame 24 and any road material surrounded by the longitudinal and transverse cuts is thereafter removed, thereby forming the hole in the road. It will be appreciated that the order of the longitudinal and transverse cuts is not important and as such, the longitudinal cylindrical cut in the road may be made prior to the transverse undercut in another embodiment of the invention. It will also be appreciated that the manhole plug 10 is configured and dimensioned so as to be fitted into the hole left behind after the removal of the existing manhole such that the manhole plug 10 substantially fills the hole. After removing the existing manhole, an annular layer of adhesive is applied to the underside of the manhole plug, and a corresponding adhesive layer is applied to the exposed part of the cover plate 32 of the service access pipe 28. The manhole plug 10 is then lowered into the hole until it rests on the cover plate. The adhesive located between the mating surfaces of the cover plate and the underside of the manhole plug effectively bonds the manhole plug to the cover plate. Thereafter, a flowable, settable filler material is introduced into the gap defined between the side wall of the road defining the hole and the peripheral side wall of the manhole plug 10. The filler material has adhesive properties which permits it to form a bond between the side wall of the road defining the hole and the manhole plug thereby further securing the manhole plug within the hole.

The Applicant envisages that one or more spacer elements may be located between the manhole plug 10 and the cover plate 32 of the service access pipe 28 thereby to raise the height of the manhole plug so that the upper side thereof is substantially flush with the road surface. With reference to Figures 7 and 8 of the drawings, two spacer elements 40.1 and 40.2 are shown. The spacer elements 40.1 and 40.2 are in the form of discs wherein the diameter of the discs when viewed in plan view, is substantially identical to the diameter of the manhole plug 10. The spacer elements 40.1 and 40.2 each define a central hole which corresponds with the diameter of the access chamber 30. The discs 40.1 and 40.2 define circular complementary tapers on their upper and lower surfaces, respectively, which permit the discs to co-operate with one another when rotated relative to one another thereby to vary the overall height to which the manhole plug can be raised or lowered within the hole.

In another embodiment of the invention, the manhole plug may be dimensioned such that it is "oversized" so that the upper end of the manhole plug projects above the surface of the road in which the manhole plug is secured, in use, thereby permitting an upper end region of the manhole plug to be removed until the upper end of the manhole plug is flush with the road surface. In this manner, by providing an "oversized" manhole plug which can subsequently be trimmed down in height, the need for the spacer discs is obviated.

It will be appreciated that the diameter of the rotary cutting barrel 36 of the core cutting rig will be matched to the diameter to the manhole plug thereby allowing for the fitment of the manhole plug into a hole which is cut by the rotary cutting barrel. Thus, the hole is sized specifically to accommodate the manhole plug 10. This greatly simplifies the construction of a new manhole to replace an existing manhole in a section of an existing road.

In a method of constructing a manhole involving the construction of a new manhole in a new section of road in which a service access structure has already been constructed, the service access opening is closed by means of a temporary cover and the new section of road is constructed over the service access structure. After the new section of road has been constructed, the service access structures are identified and located and a hole is formed in the road directly above each service access structure by making a longitudinal cut into the road using the core cutting rig described hereinabove to cut a core into the road directly above the service access structure. The road material surrounded by the longitudinal cut is then removed to form the hole in the road and the temporary cover for the service access structure is removed. The manhole pug is thereafter fitted into the hole in the road. In similar fashion to the fixing of the manhole plug 10 within the hole as described hereinabove, an adhesive is located between the cover plate of the service access structure and the annular part of the underside of the manhole plug which rests on the cover plate, thereby bonding the manhole plug to the cover plate. As for the method for replacing an existing a manhole in the road with a new manhole as described hereinabove, a flowable, settable filler material having adhesive properties is introduced into the gap between the side wall of the road defining the hole and the peripheral side of the manhole plug thereby bonding the manhole plug to the side wall of the road defining hole.

It will be appreciated that the method of constructing a new manhole in a new section of road, in accordance with the invention, will obviate the need to construct the road around manhole frames located above service access structures in the road as is conventially done. By merely temporarily covering the service access openings and constructing the road on a flat foundation without having to construct the road around upwardly projecting manholes, will greatly simplify and speed up the road construction process.

With reference to Figure 10 of the drawings, another embodiment of a manhole plug in accordance with the invention, is designated by the reference numeral 100. The manhole plug 100 is similar to the manhole plug 10, with the difference being that the moulding 1 13 thereof defines a manhole passage 120. There is thus no manhole frame in this embodiment. The manhole plug 100 is disc-shaped and has an upper end 1 14 and a lower end 1 16. In Figure 10, those features of the manhole plug 100 which are the same as and/or similar to those of the manhole plug 10, are designated by the same and/or similar reference numerals.

The invention extends to the manhole plugs 10 and 100 as described above. It will be appreciated that the exact steps of the method of constructing a manhole may be greatly variable while still incorporating the essential features of the method as described hereinabove. Similarly, the configuration of the manhole plug may vary considerably while still incorporating the essential features of the manhole plug as described and defined hereinabove.

Claims

CLAIMS:

1. A method of constructing a manhole in a road, which includes:

2. The method as claimed in claim 2, which includes forming the hole in the road by:

3. The method as claimed in claim 2, which includes making said longitudinal cut in the road using a core cutting rig having a rotary cutting barrel which is operable to make a cylindrical cut into the road material.

4. The method as claimed in any one of claims 1 to 3, which includes locating an adhesive between the cover plate of the service access structure and a part of the underside of the manhole plug which rests on the cover plate, for bonding the manhole plug to the cover plate.

5. The method as claimed in any one of claims 1 to 4, which includes introducing a flowable, settable filler material into the gap between the sides of the hole and the side wall of the manhole plug.

6. The method as claimed in claim 5, wherein the filler material may have adhesive properties which permits it to form a bond between the hole and the manhole plug.

7. The method as claimed in any one of claims 1 to 6, which includes positioning one or more spacer elements between the cover plate of the service access structure and the manhole plug thereby to raise the upper surface of the manhole plug to a height where it is substantially flush with the surrounding road surface.

8. The method as claimed in any one of claims 1 to 7, which is adapted for use in replacing an existing manhole in a road with a new manhole, the method including forming said hole in the road around the manhole to be replaced and removing the manhole and any road material surrounded by the longitudinal cut to form the hole in the road.

9. The method as claimed in claim 8, which includes forming the hole by additionally cutting into the road from within the internal passage of the manhole to be replaced at said predetermined depth in a transverse direction relative to the longitudinal axis of the hole, thereby to undercut the road material below the hole; and removing the manhole and any road material surrounded by the longitudinal and transverse cuts.

10. The method as claimed in any one of claims 1 to 7, wherein the method of constructing a manhole is adapted for use in constructing a new manhole in a new section of road, the method including constructing the new section of road over a service access chamber; locating the position of the service access chamber below the road surface of the new section of the road; forming said hole in the road directly above the service access chamber; and fitting the manhole plug into the hole thereby to provide a manhole which provides access to the service access chamber.

1 1 . A manhole plug of a predetermined shape and size, having an upper end and a lower end and defining a manhole passage which extends between and which is open at its upper and lower ends, the manhole plug being configured for use in the method of constructing a manhole in a road as claimed in any one of claims 1 to 10.