GB2232182A

GB2232182A - Access chamber and method of making same, liner and cover therefor

Info

Publication number: GB2232182A
Application number: GB9007118A
Authority: GB
Inventors: Philip Craig
Original assignee: Individual
Current assignee: Individual
Priority date: 1989-03-29
Filing date: 1990-03-29
Publication date: 1990-12-05
Also published as: GB9007118D0; GB8907060D0

Abstract

A liner (34) for an access chamber to a tank (68) connector (66) comprises a first portion (36) defining a chamber (38), a second neck portion (40) of smaller cross-sectional area than the first portion and a third portion (42) of greater cross- sectional area than the portion (40) and adapted to provide a housing for a frame (11) to support a manhole cover (10). The portion (40) inter-connects the portions (36, 42). The chamber is formed by positioning the liner (34) and pouring concrete (58) in situ round the liner (34), metal reinforcements (62) being incorporated in the concrete. Concrete adjacent the portion (40) is situated beneath the third portion (42) (and frame 11) to provide a beam (60) supporting the third portion (42) and frame (11). The cover (10) has reinforced beams (20). A cover, suitable for use as above, comprises a body portion of fibre-reinforced plastics material, a peripheral portion adapted to seat in corresponding frame means, and a lower face having thereon a plurality of integrally formed reinforcing beams. <IMAGE>

Description

CHAMBER AND METHOD OF MAKING SAME, LINER AND COVER THEREFOR This invention is concerned with chambers and methods of making them, and with liners and covers therefor.

Chambers are commonly required to permit access to underground installations, storage facilities e.g. tanks, mines, and the like. Such chambers have heretofor been built of brick.

More recently, chambers have been formed by a prefabricated plastics shell, for example as described in Patent Specification No. 1602537. However such brick constructions are very time consuming to build and access chambers as described in Patent Specification No. 1602537 are not particularly convenient in many circumstances.

Further, covers for such chambers have in the past been provided by cast iron covers: however, these are somewhat prone to fracture, are corroded by many materials and by the action of weather and are relatively heavy. It has been proposed to replace cast iron covers by covers of fibre-reinforced plastics material, for example as described in European Patent Specification No. 0147050. It is necessary that reinforced plastic covers should be sufficiently strong to withstand loads to which they may be subjected. The cover shown in European Patent No. 147050 is reasonably strong but is of a rather complex construction which may lead to manufacturing difficulties.

According to one aspect the invention may be considered to provide a cover suitable for use in covering entrances of comprising a body portion fibre-reinforced plastics material having an upper face, a peripheral portion adapted to seat in corresponding frame means, and a lower face having a plurality of integrally formed reinforcing beams thereon.

Preferably a cover in accordance with the invention comprises at least two beams which intersect to provide a cruciform reinforcement. Conveniently a cover in accordance with the invention comprises more than two beams, preferably two sets of parallel beams, each set suitably comprising three beams. Suitably the beams may be hollow and filled with plastics foam and/or other strengthening materials.

Preferably a cover in accordance with the invention also comprises an abutment formed on the peripheral portion opposite the end of each beam. Such abutments are configured to abut against a portion of a frame in which the cover is seated whereby to stabilise the loading with the deflection/friction abutments to the structure. Conveniently the peripheral portion of the cover further comprises locating means adapted to engage corresponding frame means to facilitate location of the cover in the frame means.

One preferred cover in accordance with the invention is domed to some extent and comprises an abutment opposite the end of each beam. Thus when a loading is applied to the cover, slight flexure of the cover transfers load through the abutments to the frame thereby stabilising deflation and take the loading.

A preferred cover in accordance with the invention comprises a non-slip upper surface, suitably formed integrally with the cover, and also comprises grooves extending across the peripheral portion; such grooves are intended to vent air from a chamber covered by the cover. The upper surface of a cover in accordance with the invention may, however, have any desired surface finish eg. artificial grass may provide the surface finish. The preferred cover further comprises lock means adapted to lock the cover to a surrounding frame.

In another aspect the invention may be considered to provide a liner comprising a first portion defining a chamber, a second neck portion of smaller cross-sectional area than the first portion and a third portion of greater cross-sectional area than the second portion and adapted to provide a housing for a manhole cover, the second portion being positioned between the first and third portions, interconnecting them.

A liner in accordance with the invention may be of any suitable material, for example fibre-reinforced plastics material or sheet metal e.g. steel.

In some circumstances, for example where a liner for a relatively deep chamber is to be formed, the first portion may comprise a plurality of sections connected to one another at joint regions extending transversely of the liner. Conveniently the liner comprises a joint means extending round the liner comprising two parts (each sealingly connected with one of the sections adapted to slidingly engage one another in sealing engagement. Conveniently the parts of the joint means may be incorporated in the sections during construction.

In a preferred liner in accordance with the invention the section remote from the second, neck portion comprises an end closure wall extending across the liner.

Preferably the material of which the liner is formed and the joints between sections are impervious to water transmission.

The first and third portions of a liner in accordance with the invention may have any desired cross-sectional shape and area; the second, neck portion, is configured to provide a relatively smooth transition between the first and third portions. Commonly the first and third portions may be either circular, rectangular, or square in cross-section; however, it is not essential that the first and third portions have the same cross-sectional shape.

In another aspect the invention may be considered to provide a chamber comprising a liner in accordance with the invention and a reinforced concrete shell poured in situ around the liner so that concrete adjacent the second, neck portion of the liner is situated beneath the third portion of the liner whereby to provide a beam construction supporting the third portion.

Preferably a chamber in accordance with the invention comprises metal reinforcement for the concrete, the reinforcement conveniently extending into the portion of the concrete providing said beam. A chamber in accordance with the invention preferably comprises a cover in accordance with the invention.

In yet another aspect the invention may be considered to provide a method of making a chamber comprising locating a liner in accordance with the invention in a desired position, pouring concrete around the liner, and allowing the concrete to set to form a lined chamber.

Preferably the liner is located on a concrete base.

A chamber in accordance with the invention is especially useful in providing an access chamber to an underground tank or other installation.

There now follows a detailed description, to be read with reference to the accompanying drawings, of tow coverts, a liner and a plurality of chambers in accordance with the invention. It will be realised that these items have been selected for description to illustrate the invention by way of example.

In the accompanying drawings: Figure 1 is a diagrammatic plan view from below showing diagrammatically a first cover embodying the invention; Figure 2 is a view in section on the line II-II of Figure 1; Figure 3 is a diagrammatic view showing a liner positioned to form a chamber embodying the invention; Figure 4 is a diagrammatic plan view showing a chamber embodying the invention; Figures 5 and 6 are sections of chambers embodying the invention generally similar to that shown in Figure 4; Figure 7 is a diagrammatic plan view of a further chamber embodying the invention; Figure 8 is a sectional view of the chamber shown in Figure 7; Figure 9 is a fragmentary diagrammatic sectional view showing joint means of a liner embodying the invention; Figure 10 is a fragmentary diagrammatic plan view from below of a second cover embodying the invention; and Figure 11 is a view in section on line XI-XI of Figure 10; Figure 12 is an underneath plan view of a third circular manhole cover embodying the invention; Figure 13 is a diagrammatic side view of an additional chamber embodying the invention showing in place the cover of Figure 13; Figure 14 is an underneath plan view of a fourth square manhole cover embodying the invention; Figure 15 is a side view of yet another chamber embodying the invention including a cover as shown in Figure 14; Figure 16 is a side view of the cover of Figure 14.

Figure 17 is a diagrammatic partly sectional view showing a suspended frame and chamber assembly.

A first cover 10 suitable for use in covering entrances to chambers, for example manholes is shown in Figure 1. The cover 10 is made of a fibre-reinforced plastics material, for example a glass fibre reinforced polyester material or a suitable plastics material reinforced with other fibres for example carbon fibres. The cover 10 comprises a body portion 12 having an upper face 14, a peripheral portion 18 adapted to seat in corresponding frame means, and a lower face 16 having a plurality of integrally formed reinforcing beams 20 thereon. The reinforcing beams 20 are, in the first illustrative cover, arranged in cruciform configuration and are disposed within the region of the lower face 16 surrounded by the peripheral portion, the beams 20 extending across the cover from side to side between the boundaries of the peripheral portion.The beams 20 are hollow and are filled with a suitable plastics foam to provide some additional rigidity.

The peripheral portion 18 is defined, inwardly, by a ridge 22 and outwardly by the edge 24 of the cover.

Abutments 26 are formed on the peripheral portion at the ends of each beam 20: when the cover is positioned in a corresponding frame the abutments 26 are arranged to engage members of the frame to assist in stabilising the cover in the frame.

The peripheral portion further comprises locating means namely corner abutments 28 also adapted to engage a corresponding frame, to facilitate location of the cover in the frame. Grooves 30 extend across the peripheral portion to vent air or other gaseous material from beneath the cover; one groove is formed at each corner and three grooves at each side of the illustrative cover 10.

The cover 10 also comprises lock means (not shown in the drawings) by which the cover may be-locked to a frame in which it is received. Alternatively, a lock may be incorporated into a frame and adapted to be operated to engage a part of the cover to lock the cover in position. Locks may be operated by hand, or electronic means, by acoustic means e.g. voice recognition, touch activated, or controlled by computer. Where additional security is required a dual locking system may be utilised requiring two different actions to fully unlock the cover, in a dual lock system, one of the locks may be operated by remote operation, for example through a radio link, and the other operated by a person requiring access for example to petroleum, chemical, and waste discharge systems or to military installations.Warning systems may be associated with the locks which indicate whether a cover has been tampered with.

The first illustrative cover 10 comprising beams 20 is strong and relatively light compared with other covers of similar strength. The beams 20 are believed to be especially useful in resisting deflection of the cover 10 under an applied load. Beams 20 also assist in stabilising the cover/frame assembly.

A second illustrative cover 80 is shown in Figures 10 and 11. This cover is generally similar in construction to the first illustrative cover 10 except that its peripheral portion 18 is slightly different its upper and lower surfaces 14, 16 are dome shaped to a degree and a pair of sets of beams each comprising a plurality of parallel beams (three in each set in the cover 80) extends across the lower surface 16 of the cover 80. The beams are curved, following the curvature of the lower surface 14, substantially. The curvature of the lower surface may be different from, eg. more pronounced than that of the upper surface, if desired. The doming of the surfaces 14, 16, and the additional beams provide added strength, for the most demanding applications.

By selecting an appropriate type of material, covers (10) conforming so far as possible with British Standard 497 Part 1, 1976 (which actually relates to metal covers) can be substantially complied with, the first cover 10 performing in line with standards B and C, and the cover 80 with standard A.

Furthermore glass reinforced plastics material may be rendered adequately fireproof. Where a lock is mounted in the cover (10) this is preferably positioned in one of the beams (20).

Figure 3 shows a liner 34 of fibre-reinforced plastics material. The liner comprises a first portion 36 defining a chamber 38, a second, neck portion 40 of smaller cross-sectional area than the portion 36 and a third portion 42 of greater cross-sectional area than the second portion 40, the portion 42 being adapted to provide a housing for a frame for a cover, for example the illustrative cover 10. The second portion 40 is positioned between the first and third portions 36, 42, interconnecting them.In the illustrative liner, the first and third portions are both generally square in cross-sectional area and the portion 40 is of a similar cross-sectional shape; however, liners in accordance with the invention may comprise a first portion 36 which is circular in cross-sectional area with a third portion 42 which is square in cross-section, in which case the second portion 40 is configured to smoothly interconnect the first and third portions 36, 42.

The first portion 36 is made up of a number of sections 44, 46, 48 which are connected to one another at joint regions 50 which extend transversely of the liner 34. The sections 44, 46, 48 are connected to one another by joint means extending around the sections comprising two parts, one associated with each section, one part being adapted to slidingly receive a cooperating joint part of an adjacent one of the sections.

Suitably, a socket type joint part may be incorporated in one of the sections during construction and a joint part having a plug portion adapted to cooperate with the socket portion of the first joint part may be incorporated in an adjacent section during manufacture. Conveniently the socket portion may additionally be filled with a sealant before the sections are assembled together so that the joint is completely watertight.

Figure 9 shows one form of joint means which has been proposed. As can be seen from Figure 9, a first joint part 52 comprises a socket portion having two grooves within which corresponding projecting plug portions of a second joint part 54 are received. The socket portion may first be filled with sealant.

The first portion 36 of the liner may comprise any desired number of sections and the number and length of sections is selected to ensure that the upper edge of the third portion is at a desired ground level (see for example Figures 5, 6 and 8).

The lowermost section 48 has an end closure wall 56 extending across the liner.

Figure 3 shows also, diagrammatically, a chamber embodying the invention comprising the liner 34 and a reinforced concrete shell 58, the concrete being poured in situ around the liner 34.

As can be seen viewing Figure 3 the concrete adjacent the second, neck portion 40 of the liner 34 is situated beneath the third portion 42 whereby to provide a beam 60 supporting the third portion 42. The concrete comprises metal reinforcement which may, for example be provided by steel rods, steel mesh or a suitable steel framework 62. Portions 64 of the metal reinforcement 42 extend into the portion of concrete providing the beam 60. Thus the beam 60 is formed of reinforced concrete and provides a strong firm support for a frame 11 in which the cover 10 may be located. This construction providing a beam of reinforced concrete supporting the frame is especially important where the chamber 38 is of considerably greater cross-sectional area than the third portion 42.

In Figure 3, the chamber 38 is an access chamber for a connector 66 to an underground storage tank 68 e.g. for petrol or the like. When installing the liner 34, a concrete foundation layer 70 is first cast on an upper surface of the tank 68 around the connector 66 and when this has set, the lowermost section 48 of the portion 36 of the liner is positioned on the foundation layer 70, a hole through which the connector 66 can pass being cut in an end wall 56 of the section 48. Sealant 72 is then introduced around the connector 66 to seal the opening in the end wall 56 to prevent ingress of moisture into the chamber 38.

Openings may be cut it the side wall of the section 48 so that connection pipes 74 may pass to the connector 56. The openings through which the pipes 74 pass may be lengthwise slots open at an upper end portion so that the section 48 may be slid into position round the pipes, before they have been connected to the connector 66. The next adjacent section 46 is then connected to the section 48 using suitable sealing joint means for example as shown in section in Figure 9 which extend around the whole periphery of the upper wall of the section 48 and the lower wall of the section 46. The upper section 44 is finally positioned in the same way on the section 46. If desired, the upper section 44 may be formed integrally with the neck portion 40 and the third portion 42.Having assembled the liner 34, concrete 58 is poured into suitable shuttering (or into a pit formed in the ground), after, having positioned the reinforcement 62 appropriately, and allowed to set. The chamber 38 is sealed by the liner against ingress of moisture through the walls and the cover 10, closing the open third portion, together with the supporting frame accommodated in the portion 42, prevents ingress of moisture or other liquids from above. It will be appreciated that suitable seals 75 are formed where any pipework passes through the liner.

Figure 4 is a view in plan showing another chamber and associated pipework and Figures 5 and 6 are vertical sections of chambers similar to the chamber shown in Figure 4 but in different situations. As can be seen, the upper surface of the cover 10 is raised slightly above the surrounding ground level G so that the risk of liquids draining into the chamber 38 from the ground G is reduced.

Figure 7 is a plan view of a further chamber 38 embodying the invention utilising a liner 34 of generally similar configuration to the liner shown in Figure 3 though of somewhat smaller height. Figure 8 shows the chamber of Figure 7 in vertical section and, again, it can be seen that the cover 10 is raised above the level of the surrounding ground G. In Figures 6 and 8 a frame 11 by which the cover 10 is located is shown in position, housed in a recess provided by the portion 42 of the liner.

In Figures 3 to 8, like reference numbers indicate like parts.

The third illustrative cover 110 is circular in underneath plan and comprises a flat upper surface 112 and a lower surface 114 which is generally domed upwardly (see Figure 13) and is provided with two concentric annular ribs which are domed upwardly. The cover 110 is formed of a glass fibre reinforced plastics material hollow shell filled with a suitable stable foam for added strength. A socket 120 is provided at a central region of the cover in order to facilitate lifting it from the frame.

The chamber shown in Figure 13 is of either two or three parts. Desirably, there are three sections 122, 124, 126, end portions of one being adapted to sealingly engage within adjacent end portions of the neck section. The neck section 126 may be configured so that at its upper end portion it can receive either a square or circular frame (see also Figure 15), the parts 122, 124 being similar in either case.

The fourth illustrative cover 130 is square and likewise is formed of a resin-impregnated fibreglass material filled with a suitable foam. The cover 130 likewise has a flat upper surface 132 and is provided with a plurality of ribs 134 on its lower surface. The ribs 134 are parallel and opposite end portions are positioned to abut parts of a frame 138. The outer ribs 134 are provided with outwardly directed projections 136 which are likewise arranged to abut a frame 138 when the cover 130 is inserted in the frame. The frames 113, 138 of the chambers shown in Figures 13 and 15 may be supported in a manner similar to that described previously with reference to Figures 1 to 11.

Alternatively, the frames may be secured firmly to the top sections 126, 126a of the chambers, for example by means of appropriate fastenings, for example bolts, the various sections 122, 124, 126 being likewise secured firmly to one another by mechanical fasteners. The whole chamber can then be supported in such a manner that little or no load is placed on a tank positioned beneath the lowermost section 122 of the chamber.

Such tanks are commonly made of plastics material and are unable to stand any substantial load which might be transmitted through the chamber when a lorry or the like passes across the top of the chamber. In order to support the frame 113 concrete 140 is cast around the chamber 122, 124, 126, the concrete including steel reinforcements 142 around and beneath the frame 113 which is suitably of steel. The steel reinforcements 142, e.g. of steel wire mesh, extend generally horizontally away from the frame and chamber so that the steel reinforcements 142 support the frame 113 and distribute the load of the frame over a substantial area of concrete around the chamber. As the chamber itself is supported from the frame 113 by bolts 144 the load of the whole frame chamber/cover assembly is distributed over a substantial area by the concrete 140 and steel reinforcements 142 and little or no load is transferred to any tank beneath the chamber.

The various chambers shown in the drawings are of waterproof construction, even the regions at which pipes 74 pass through the impervious liner 34, which are sealed by sealing means 75, a connector 66 where it passes through the end wall 56 likewise being sealed by sealing means 72.

The illustrative chambers are relatively quick and simple to construct and inexpensive by comparison with brick built inspection chambers and the like.

Claims

1. A cover suitable for use in covering entrances comprising a body portion of fibre-reinforced plastics material having an upper face, a peripheral portion adapted to seat in corresponding frame means, and a lower face having a plurality of integrally formed reinforcing beams thereon.

2. A cover according to Claim 1 comprising at least two beams which intersect to provide a cruciform reinforcement.

3. A cover according to either one claims 1 and 2 comprising two intersecting sets of parallel beams.

4. A cover according to either one of Claims 1 and 2 comprising an abutment formed on the peripheral portion opposite the end of each beam.

5. A cover according to any one of the preceding claims which is domed.

6. A cover according to any one of the preceding claims wherein the beams are hollow.

7. A cover according to Claim 6 wherein the beams are filled with plastics foam.

8. A cover according to claim 6 wherein the beams are filled with strengthening materials

9. A cover according to any one of the preceding claims wherein the peripheral portion comprises locating means adapted to engage a corresponding frame to facilitate location of the cover in the frame.

10. A cover according to any one of the preceding claims comprising a non-slip upper surface.

11. A cover according to any one of the preceding claims comprising grooves extending across the peripheral portion.

12. A cover according to any one of the preceding claims comprising lock means adapted to lock the cover to a frame.

13. A cover constructed arranged and adapted to operate substantially as hereinbefore described with reference to Figures 1 and 2 of the accompanying drawings.

14. A cover constructed arranged and adapted to operate substantially as hereinbefore described with reference to Figures 10 and 11 of the accompanying drawings.

15. A liner comprising a first portion defining a chamber, a second neck portion of smaller cross-sectional area than the first portion and a third portion of greater cross-sectional area than the second portion and adapted to provide a housing for a manhole cover, the second portion being positioned between the first and third portions, interconnecting them.

16. A liner according to Claim 15 of fibre reinforced plastics material.

17. A liner according to Claim 15 of sheet metal.

18. A liner according to any one of Claims 16 to 18 wherein the first portion comprises a plurality of sections connected to one another at joint regions extending transversely of the liner.

19. A liner according to Claim 18 comprising a joint part extending round one of said sections and adapted to slidingly receive a co-operating joint part of an adjacent one of said sections in sealing engagement.

20. A liner according to Claim 19 of fibre-reinforced plastics wherein each of the joint parts is incorporated in one of said sections during construction.

21. A line according to any one of Claims 18 to 20 wherein the section remote from said second portion comprises an end closure wall extending across the liner.

22. A liner substantially as hereinbefore described with reference to Figure 3 of the accompanying drawings.

23. A chamber comprising a liner according to any one of Claims 15 to 22 and a reinforced concrete shell poured in situ around the liner so that the concrete adjacent the second, neck portion of the liner is situated to provide a beam supporting the third portion.

24. A chamber according to Claim 23 wherein the concrete comprises metal reinforcements extending into the portion of concrete providing said beam.

25. A chamber according to either one of Claims 23 and 24 comprising a cover according to any one of Claims 1 to 14.

26. A method of making a chamber comprising locating a liner according to any one of Claims 15 to 22 in a desired position, pouring concrete around said liner, and allowing the concrete to set to form a lined chamber.

27. A method according to Claim 26 wherein the liner is located on a concrete base.

28. A cover according to Claim 1 wherein the cover is circular in plan and the reinforcing beams are concentric with the cover.

29. A cover according to Claim 28 wherein the lower face is domed upwardly.

30. A cover according to either one of Claims 28 and 29 wherein the fibre-reinforce plastics material provides an external shell filled with plastics foam.

31. A liner comprising a first portion defining a chamber, a second, neck portion of smaller cross-sectional area than the first portion and adapted to be connected to the first portion at one end portion the opposite end portion being received in a housing in a frame to locate the frame on the neck portion.

32. A chamber comprising a liner according to any one of Claims 15 to 21 and 31 secured to a frame for a cover.

33. A chamber according to Claim 32 comprising a reinforced concrete support layer poured in situ around at least part of the liner and including reinforcements extending beneath the frame whereby the frame and chamber are suspended by the reinforced concrete.