WO2013163700A1

WO2013163700A1 - Construction method and components

Info

Publication number: WO2013163700A1
Application number: PCT/AU2013/000466
Authority: WO
Inventors: Stephen Clifford Smith; Len LINES
Original assignee: Pacific Composites Pty Ltd
Priority date: 2012-05-04
Filing date: 2013-05-06
Publication date: 2013-11-07

Abstract

A structural module comprising a generally plank-shaped body comprising: a pair of opposing main face walls spaced from each other and defining a pair of main faces of the body, a pair of longitudinally corrugated side walls joining respective edges of said main face walls and sloping relative to said main faces, and a plurality of reinforcing web walls joining said main face walls internally of said body and forming a plurality of longitudinal closed ducts within said body.

Description

CONSTRUCTION METHOD AND COMPONENTS Field of the Invention This invention concerns covers used to span spaces, particularly those spaces where it is required that the covers provide a barrier to the flow of gases. Embodiments of the invention are particularl useful for covers over waste water channels in sewerage treatment works where a barrier is required to reduce the emission of odorous gases from the channels.

Background of the Invention

In large scale sewerage treatment works, waste water is commonly directed down concrete lined channels. There is an increasing desire to reduce the evolution of odours from sewerage treatment works and part of the desired abatement system requires that the open channels are covered using a system that eliminates, or at least greatly reduces, the uncontrolled release of odourous gases from the channels. Typically such channel widths require covers to span around 3.5 to 5 metres. There is a need for a modular system of components which allows for assembly of covers for such channels of any desirable length and width, and which does so using only a small variety of components.

While it is important that a substantially air-tight seal is provided between the modular components, it is also desirable that sections of the cover be readily removable and replaceable from time to time to allow for general maintenance activities. For safety reasons the covers are preferably strong enough to be trafficable by individual persons. Such covers also need to be resistant to the highly corrosive atmosphere which can exist within the covered channels.

There is a need for a cover which addresses some, and preferably all, of the problems indicated above. Summary of the Invention

Accordingly, in one aspect the invention provides a structural module comprising a generally plank-shaped body comprising:

- a pair of opposing main face walls spaced from each other and defining a pair of main faces of the body,

- a pair of longitudinally corrugated side walls joining respective edges of said main face walls and sloping relative to said main faces, and

- a plurality of reinforcing web walls joining said main face walls internally of said body and forming a plurality of longitudinal closed ducts within said body.

Preferably the module is formed integrally as a pultruded fibre reinforced plastic component. Preferably said main face walls and said side walls are of substantially the same thickness. Preferably each said side wall has as a major feature a generally flat side wall portion aligned at right angles to said main faces. Preferably adjacent to said generally flat side wall portion, each said side wall incorporates an acute bend which forms a ridge or a valley along said each side wall.

Each said side wall may incorporate an acute bend which forms a distally protruding ridge extending from less distal than said generally flat side wall portion. Alternatively, adjacent to said generally flat side wall portion, each said side wall may incorporate an acute bend which forms a valley more distal than said generally flat side wall portion.

Each said side wall in the structural module may incorporate an approximately right angular bend adjacent to and in the opposite direction to said acute bend. Preferably each said side wall carries an elastomeric seal along the length of the body. Each said side wall may carry a pair of elastomeric seals along the length of the module, a first of said pair of seals is positioned adjacent a first of said main faces and the sepond of said pair of seals is positioned adjacent the second of said main faces. In another aspect the invention provides a structural panel comprising a plurality of structural modules as defined above, wherein:

- said structural modules are fastened together side by side with the respective side walls of adjacent said modules abutting each other, and

- said corrugations of abutting said side walls interengage to prevent said structural modules from moving apart.

Preferably the body of a first selection of said modules has a first cross sectional shape, the body of a second selection of said modules has a second cross-sectional shape different to that of said first cross sectional shape, and said modules from the first selection alternate with modules of the second selection.

Preferably each said side wall of the modules in said first selection retains an elastomeric seal along its length and said seal is compressed against an adjacent side wall of a module in said second selection. The side walls of the modules in said second selection may have no elastomeric seals fastened thereto.

In another aspect the invention provides a cover for a channel containing odorous waste water, said cover comprising a plurality of structural modules according to any one of claims 1 to 4 laid side by side with their adjacent side walls overlapping and wherein:

- each said module extends across the channel, and

- said corrugations in a first overlapped said side wall mate with and are interlocked with the corrugations in an adjacent second overlapped said side wall. In another aspect the invention provides a cover for a channel containing odorous waste water, said cover comprising a plurality of structural modules, each said module extending across the channel, and each said module comprising:

- a generally plank-shaped body,

- a plurality of reinforcing web walls joining said main face walls internally of said body and forming a plurality of longitudinal closed ducts within said body,

wherein:

- the bodies of a first selection of said modules have a first cross-sectional shape,

- the bodies of a second selection of said modules have a second cross-sectional shape different to that of said first cross-sectional shape,

- the modules are laid side by side with their adjacent respective side walls overlapping, and

- the modules from the first selection alternate with modules of the second selection.

Preferably said corrugations in a first overlapped said side wall mate with and are interlocked with the corrugations in an adjacent second overlapped said side wall. In another aspect the invention provides a method of constructing a cover for a channel containing odorous waste water, said cover comprising a plurality of structural modules according to any one of claims 1 to 5, a first selection of said modules having a first cross-sectional shape, and a second selection of said modules having a second cross-sectional shape different to that of said first cross-sectional shape, said method comprising:

- laying in place across the channel a first module from said first selection, - laying in place across the channel a second module from said first selection such that the first and second modules are parallel and spaced apart, and

- laying in place across the channel between said first and second modules a third module from said second selection such that the side walls of said third module engage with respective side walls of the first and second modules, and

- a downwardly extending ridge on each said side wall of said third module engages with and nests neatly within a respective upwardly opening valley on each said engaged side wall of the first and second modules.

Brief Description of the Drawings

In order that the invention may be more fully understood there will now be described, by way of example only, preferred embodiments and other elements of the invention with reference to the accompanying drawings where:

Figure 1 is a partially exploded view of a cover according to a first embodiment of the present invention;

Figure 2 is an exploded view of a first configuration of structural module used to form the cover in Figure 1 ;

Figure 3 is a cross-section view through the structural module in Figure 2;

Figure 4 is a front view of an end cap used in the structural module of Figure 5; Figure 5 is a rear view of the end cap in Figure 4;

Figure 6 is a side view of the end cap in Figure 4;

Figure 7 is an exploded view of portion of a second type of structural module used in the cover in Figure 1 ;

Figure 8 is a cross-section through the structural module in Figure 7;

Figure 9 is a cross-section through a rubber seal used in the module of Figure 7;

Figure 10 is a front view of an end cap used in the structural module of Figure

7;

Figure 11 is a rear view of the end cap in Figure 10;

Figure 12 is a side view of the end cap in Figure 10;

Figure 13 is a cross-section view showing the manner of overlapped connection between one of the Figure 2 modules and one of the Figure 7 modules; Figure 14 is a cross-section of a structural panel formed from two of the Figure 2 modules and one of the Figure 7 modules; and

Figure 15 is a cross-section view of a structural panel formed from one of the Figure 2 modules and two of the Figure 7 modules.

Detailed Description of the Preferred Embodiments

The cover 10 shown in Figure 1 is a fabrication assembled from a pair of end supports 12 and 13 a pair of side supports 14 and 1 , and multiple structural modules 18 and 38 together with various aperture components. The structural modules 18 and 38 are different from each other and alternate with each other along the cover.

In use the side supports 14 and 15 lie on opposite sides of a channel 16 containing odorous waste water. The modules 18 and 38 each span the channel. The water channel is not shown in the Figures but its position is indicated by the arrow 16 in Figure 1. The main purpose of the cover 10 is to prevent escape of odours from the channel 16 into the surrounding environment. For safety reasons the cover is also trafficable by persons on foot for maintenance. The upper structural modules 18 each comprise a body portion 19, a pair of end caps 20 which fit snugly onto respective ends of the body portion 19, and four rubber strip seals 37 and 38. The lower structural modules 48 each comprise a body portion 49 and a pair of end caps 50 which fit snugly into respective ends of the body portion 49. In order to provide effective gas tightness across the cover 10, the modules 18 and 38 have two elastomeric seals 37 and 38 compressed therebetween. Seals are also provided between the structural modules and the side supports 14 arid 15 and the end supports. The respective body portions of each of the structural modules 18 and 48 have a constant cross section and their length is selected to suit the width of the channel being covered by the cover 10. For each structural module 18, the body portion 19 is a generally plank-shaped body having a pair of opposing main face walls 21 and 22 which are spaced from each other and define a pair of main external faces 23 and 24 of the body portion 19. The upper main face 23 is wider than the lower main face 24.

The cross section of the body portion 19 is symmetrical about its vertical centreline 36 shown in Figure 8. The side walls 25 and 26 join the upper main face wall 21 at the edges 27 and join the lower main face wall 22 at the edges 28. The side walls 25 and 26 are longitudinally corrugated but follow a general direction which slopes at about 45° to the main faces 23 and 24. Although the general slope of the side walls is about 45°, the corrugations therein result in substantial deviations from that general direction in places. Each side wall 25 and 26 is a mirror image of the other so the following, description of the wall 25 can be applied to wall 26 also.

At the upper end of the side wall 25 is an upper shallow lipped channel 80 which in use retains an upper rubber seal 37 the structure of which is described later in this specification. The channel 80 is located on that portion of the side wall 25 closest to the wide main face 23. The channel 80 is formed on a short length of the rear face of the upper main face wall 21.

Immediately adjacent the channel 80 is a relatively wide flat side-wall portion 81 which is a major feature of the side wall 25 and is aligned at right angles to the main faces 23 and 24.

At the lower end of the flat portion 81 is an acute bend directed back towards the upper main face wall 21 and which forms a ridge 82 which protrudes distally from the body 19. The acute bend is directed towards the centreline 36 so the ridge 82 is located slightly less distally than the flat portion 81. On its proximal side the ridge 82 terminates at a right angled bend 83 after which the side wall continues towards the narrow main face 24 at about 45° to the narrow main face. At the lower end of the side wall 25 is a lower shallow lipped channel 85 which in use retains a lower rubber seal 38.

Internal to the body portion 19, three reinforcing web walls 29, 30 and 31 join the main face walls 21 and 22 to each other. The main face walls 21 and 22, side walls 25 and 26 and web walls together form four longitudinal enclosed ducts 32 to 35 within the body 19. The web walls 29 to 31 provide structural support to the main face walls 21 and 22 in the manner of a box-section construction. The main face walls 21 and 22 and side walls 25 and 26 are all of substantially the same thickness, but the web walls 29 to 31 are thinner.

Each end cap 20 has a main wall portion 40 having a front face 41 and a rear face 42. Extending from the rear face 42 are two structures which form two box-section features 43 and 44 which in use engage into respective ducts 33 and 34 as a snug fit.

The end caps 20 are glued into that position using an appropriate structural adhesive.

An edge flange 45 extends forwards from the front face 41 at the edge 28 of the end cap 20. The flange provides substantial longitudinal rigidity to the end cap 20 and strength to the end of the module 18.

Each elastomeric rubber seal 37 and 38 comprises an elongate rubber extrusion 76 which has a T-shaped foot 77, which is held within a respective channel 80 and 85 on module 18, and a hollow compressible portion 78 which is squeezed when mating body portions are interengaged.

For each structural module 48, the body portion 49 is a generally plank-shaped body having a pair of opposing main face walls 51 and 52 which are spaced from each other and define a pair of main external faces 53 and 54 of the body portion 49. The upper main face 53 is narrower than the lower main face 54. The side walls 55 and 56 join the narrower upper main face wall 51 at the edges 57 and join the wider lower main face wall 52 at the edges 58. The side walls 55 and 56 are corrugated but follow a general direction which slopes at about 45° to the main faces 53 and 54. Although the general slope of the side walls is as described, the corrugations therein result in substantial deviations from that general direction in places.

Each side wall 55 and 56 is a mirror image of the other so the following description of the wall 55 can be applied to wall 56 also.

At the upper end of the side wall 55 is an indent 87 which in use receives an upper rubber seal 37 on upper structural module 18. The indent 87 is located on that portion of the side wall 55 closest to the narrow main face 53. Immediately adjacent the indent 87 is a relatively deep flat side-wall portion 88 which is a major feature of the side wall 55 and is aligned at right angles to the main faces 53 and 54.

At the lower end of the flat portion 88 is an acute bend directed back upwards and which forms a valley89 in the side wall 55. The acute bend is directed away from the centreline 66 so the valley 89 is located slightly more distal than the flat portion 81.

On its distal side the valley 89 terminates at a right angled bend 90 after which the side wall continues as a flat wall portion 91 angled at about 45° to the wide main face 54. At the distal end of the flat wall portion 91 the side wall 55 deviates for a short section 92 at right angles to the wide main face 54. This provides a recess between the adjacent structural modules in order to accommodate the hollow portion 76 of the lower rubber seal 38. Internal to the body portion 49, five reinforcing web walls 59, 60 and 61 join the main face walls 51 and 52 to each other. The cross section of the body portion 49 is symmetrical about its vertical centreline 66 so the two walls 59 are the same as each other and the two walls 61 are the same as each other. The main face walls 51 and 52, side walls 55 and 56 and web walls 59 to 61 together form six longitudinal enclosed ducts 62 to 64 within the body 49. The web walls 59 to 61 provide structural support to the main face walls 61 and 62, and to the body portion 49 in general in the manner of a box-section construction. The main face walls 51 and 52 and side walls 55 and 56 are all of substantially the same thickness, but the web walls 59 to 61 are thinner.

Each end cap 50 has a main wall portion 70 having a front face 71 and a rear face 72. Extending from the rear face 72 are two structures which form two box-section features 73 and 74 which in use engage into respective central ducts 62 as a snug fit. The end caps 50 are glued into that position using an appropriate structural adhesive. An edge flange 75 extends forwards from the front face 71 at the edge 58 of the end cap 50 and provides substantial longitudinal rigidity to the end cap 50 and strength to the end of the module 48.

When used to make a cover 10 spanning up to about 5.5 metres, a suitable upper body portion is about 50 cm wide and a suitable lower body portion is about 57 cm wide. For both body portions the total thickness between the main faces is about 10 cm and they weigh about 13 kg per metre.

A cover 10 for a water channel may be constructed by lifting a. plurality of structural modules 18 and 48 so they each span the channel 16 and then interlocking their respective side walls. To do this, when working from a constructing edge of a cover 10, which edge comprises a first lower structural module 48 with its wide main face 54 lowermost, a second lower structural module 48 is first aligned a set distance away from the constructing edge also with its wide main face lowermost. The set distance is about the width of the narrow main face 22 of upper module 18. An upper structural module 18 is then lowered, with its narrow main face 22 lowermost, into the region between the first and second structural modules such that both its downwardly projecting ridges 82 are inter-engaged with the respective valleys 89 on the first and second structural modules. The steps of positioning a second lower module out from the edge, followed by engaging an upper module, are then repeated.

Before positioning the modules 18 and 48 over the channel however, rails forming side supports 14 and 15 are provided along each side of the channel 16 and these support the ends of the structural modules 18 and 48. The supports 14 and 15 are roll-formed stainless steel sections mounted on respective rubber pads which in turn are mounted on carefully leveled concrete plinths on each respective side of the channel 16. Rubber seals compressed between the panel ends and the supports 14 and 15 provide additional airtightness to the cover.

It will be appreciated that when a cover of this type is used to span a significant distance, the structural modules will sag a little in the centre. Therefore, in order to ensure proper drainage of rainwater falling on the cover 10, the support 14 at a first side of the cover 10 is raised higher than the support 15 on the second side.

Fibre reinforced plastic (FRP) is particularly suited for manufacturing the body portions 19 and 49 because they can be made relatively lightweight and strong and of appropriately corrosion resistant materials. A pultruded fibre reinforced composite is preferred. Especially preferred is a glass fibre reinforced plastic formed as a pultrusion. Where the cover is required for a waste water channel at a sewerage treatment works, a particularly suitable material for manufacture of those components would be a glass fibre reinforced iso-polyester or vinyl-ester resin. Fibres with a higher stiffness may be used where required. The end caps 20 and 50 are suitably manufactured as a glass fibre reinforced vinyl ester injection moulding.

As an alternative to the cover construction method described above, some preassembly may be undertaken before the modules are lifted over the channel. Three structural modules may be first connected along their edges as described above, but away from the channel, and optionally in an off-site factory. Those modules are fastened together in the required configuration to form a structural panel. Two configurations of such panels 96 and 97 are shown in Figures 14 and 15 respectively. For the panel 96 the two outside modules are each a lower structural module 48 whereas for the panel 97 the two outside modules are each an upper structural module 18. On-site each panel is lifted into position by crane to span the relevant water channel.

Many construction options are possible by using panels in this manner. For example multiple panels 96 can be craned into position and be connected by single upper modules 18. The use of such panels combines the advantages of maximizing factory assembly of structural components to better control alignment, while also providing for easy later lifting and replacement of individual structural modules 18 or panels 97 to provide access to the channel for maintenance.

Suitable lifting rings or hooks (not shown in the drawings) may be provided at one or more corners of each module or panel.

Figure 1 illustrates how a square access hatch 98 may be provided in a panel 97 for insertion where desired in the cover 10. Space for the hatch is provided by using one structural module shorter than the surrounding structural modules. The hatch 98, its associated surround frame and its affixing hardware are preferably made of stainless steel.

Small pipe penetrations 99 and large pipe penetrations 100 and 101, are also shown in Figure 1. For strength reasons all such penetrations are preferably incorporated close to the sides of the channel 16.

Whilst the above description includes the preferred embodiments of the invention, it is to be understood that many variations, alterations, modifications and/or additions may be introduced into the constructions and arrangements of parts previously described without departing from the essential features or the spirit or ambit of the invention in its broadest sense. It will be also understood that where the word "comprise", and variations such as "comprises" and "comprising", are used in this specification, unless the context requires otherwise such use is intended to imply the inclusion of a stated feature or features but is not to be taken as excluding the presence of other feature or features.

The reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that such prior art forms part of the common general knowledge.

Claims

1. A structural module comprising a generally plank-shaped body comprising:

2. A structural module according to claim 1 formed integrally as a pultruded fibre reinforced plastic component.

3. A structural module according to claim 1 or 2 wherein said main face walls and said side walls are of substantially the same thickness.

4. A structural module according to any one of claims 1 to 3 wherein each said side wall has as a major feature a generally flat side wall portion aligned at right angles to said mai faces.

5. A structural module according to claim 4 wherein, adjacent to said generally flat side wall portion, each said side wall incorporates an acute bend which forms a ridge or a valley along said each side wall.

6. A structural module according to claim 4 wherein, adjacent to said generally flat side wall portion, each said side wall incorporates an acute bend which forms a distally protruding ridge extending from less distal than said generally flat side wall portion.

7. A structural module according to claim 4 wherein, adjacent to said generally flat side wall portion, each said side wall incorporates an acute bend which forms a valley more distal than said generally flat side wall portion.

8. A structural module according to any one of claims 5 to 7 wherein each said side walHncorporates an approximately right angular bend adjacent to and in the opposite direction to said acute bend.

9. A structural module, according to any one of claims 1 to 6 wherein each said side wall carries an elastomeric seal along the length of the body.

10. A structural module according to claim 9 wherein each said side wall carries a pair of elastomeric seals along the length of the module, a first of said pair of seals is positioned adjacent a first of said main faces and the second of said pair of seals is positioned adjacent the second of said main faces.

1 1. A structural panel comprising a plurality of structural modules according to any one of claims 1 to 5, wherein:

12. A structural panel according to claim 11, wherein the body of a first selection of said modules has a first cross sectional shape, the body of a second selection of said modules has a second cross-sectional shape different to that of said first cross sectional shape, and said modules from the first selection alternate with modules of the second selection.

13. A structural panel according to claim 12 wherein each said side wall of the modules in said first selection retains an elastomeric seal along its length and said seal is compressed against an adjacent side wall of a module in said second selection.

14. A structural panel according to claim 13 wherein said side walls of the modules in said second selection have no elastomeric seals fastened thereto.

15. A cover for a channel containing odorous waste water, said cover comprising a plurality of structural modules according to any one of claims 1 to 4 laid side by side with their adjacent side walls overlapping and wherein:

- each said module extends across the channel, and

- said corrugations in a first overlapped said side wall mate with and are interlocked with the corrugations in an adjacent second overlapped said side wall.

16. A cover for a channel containing odorous waste water, said cover comprising a plurality of structural modules, each said module extending across the channel, and each said module comprising:

- a generally plank-shaped body,

- a pair of opposing main face walls spaced from each other and defining a pair of main faces of the body, \

wherein:

- the modules are laid side by side with their adjacent respective side walls overlapping, and - the modules from the first selection alternate with modules of the second selection.

17. A cover according to claim 16 wherein said corrugations in a first overlapped said side wall mate with and are interlocked with the corrugations in an adjacent second overlapped said side wall.

18. A method of constructing a cover for a channel containing odorous waste water, said cover comprising a plurality of structural modules according to any one of claims 1 to 5, a first selection of said modules having a first cross-sectional shape, and a second selection of said modules having a second cross-sectional shape different to that of said first cross-sectional shape, said method comprising:

- laying in place across the channel a first module from said first selection,

- laying in place across the channel a second module from said first selection such that the first and second modules are parallel and spaced apart, and