GB2617369A

GB2617369A - Improvements in or relating to cementitious chambers

Info

Publication number: GB2617369A
Application number: GB2205037.1A
Authority: GB
Inventors: Wadley Natalie; Wadley Luke; Hosford Paul
Original assignee: Changemaker 3d Ltd
Current assignee: Changemaker 3d Ltd
Priority date: 2022-04-06
Filing date: 2022-04-06
Publication date: 2023-10-11
Also published as: GB202205037D0

Abstract

3D printed cementitious chamber 10 comprising an external wall 12 that has a first portion 28 with first wall thickness 30 and second portion 32 with second wall thickness 34. The second wall thickness 34 is greater than the first wall thickness 30, and the second portion 32 is positioned in a higher loading region than the first portion 28. The second wall thickness may be at least 1.5 times greater than the first wall thickness and may be twice as great as the first wall thickness. The second portion may lie below the first portion. The second portion may have a height that is less than 10% of the overall height of the external wall. The first and second portions may have a height ratio of at least 11:1. The external wall may sit on a cementitious base slab which may include a reinforced concrete. The slab may include anchor points. Also claimed is a method of constructing a cementitious chamber by 3D printing an external wall having first and second portions having wall thicknesses, the second portion wall thickness being greater than the first portion wall thickness.

Description

IMPROVEMENTS IN OR RELATING TO CEMENTITIOUS CHAMBERS

This invention relates to a 3D printed cementitious chamber, such as a fluid distribution chamber or a manhole chamber, and a method of constructing a such a cementitious chamber.

Cementitious chambers, i.e. spaces that are formed from a material having the properties of cement and which are at least partially enclosed, have a wide range of uses, particularly in civil engineering projects.

For example manhole chambers, which may also be known as "inspection chambers" allow for the inspection of underground infrastructure as well as, in some instances, access to that infrastructure by engineering personnel.

Also, where wastewater treatment is used to remove contaminants from sewage to produce an effluent that is suitable for discharge to the surrounding environment or an intended reuse application, to prevent water pollution from raw sewage discharges, fluid distribution chambers are an important component in such wastewater treatment processes.

According to a first aspect of the invention there is provided a 3D printed cementitious chamber comprising an external wall having a first portion with a first wall thickness and a second portion with a second wall thickness greater than the first wall thickness, the second portion being positioned in-use in a higher loading region than the first portion.

Such a chamber utilises the greater manufacturing flexibility provided by 3D printing, and in particular makes use of the ability to vary material thickness to include larger amounts of printed cementitious material where forces are greater, i.e. in a higher loading region, and less material where forces are less. This, in turn, advantageously allows the fluid distribution chamber of the invention to minimise the amount of cementitious material needed to complete its construction while nevertheless withstanding the forces it is subjected to when being used. Such forces may, for example, take the form of external pressure from surrounding material in the case of a manhole chamber of the invention submerged in such material. They may also emanate internally from a fluid, e.g. water, retained or carried by a fluid distribution chamber of the invention which is able to withstand such forces utilising only its unreinforced tensile strength.

Preferably the second wall thickness is at least 1.5 times greater than the first wall thickness.

In a preferred embodiment of the invention the second wall thickness is twice as great as the first wall thickness.

Such thickness ratios desirably provide a necessary increase in strength, e.g. tensile, of the external wall in those regions where forces are greatest, without unduly utilising too much cementitious material and thereby unnecessarily increasing the construction cost of the chamber.

The second portion may lie in-use below the first portion.

Such an arrangement desirably positions the strongest portion of the chamber in a region most heavily impacted by the mass of a substance, e.g. a building material or fluid, lying above.

Optionally the second portion of the external wall has a height which is less than 10% of the overall height of the external wall, and preferably the first and second portions of the external wall have a height ratio of at least 11:1.

Providing an external wall with second portion having a height that is relatively low compared to the height of the first portion means that increased strength, e.g. tensile, (and hence an increased amount of cementitious material) is only deployed where it is needed and most effective, and thus an unnecessary increase in construction costs is beneficially avoided.

Preferably the fluid distribution chamber further comprises a cementitious base slab upon which the external wall sits.

The base slab may be or include a reinforced concrete section upon which lies a 3D printed cementitious layer.

Reinforced concrete sections can be produced economically and in a manner which controls heat generation to avoid cracking, while the inclusion of a 3D printed cementitious layer thereupon helps to ensure continuity, and thus fluid impermeability, between the base slab and the external and internal walls.

Optionally the base slab includes a plurality of anchor points.

Including a plurality of anchor points desirably facilitates lifting and moving of the chamber, as well as helping to ensure even static weight distribution when doing so.

In another preferred embodiment of the invention the base slab is or includes a 3D printed cementitious section.

The inclusion of a 3D printed cementitious section advantageously provides the opportunity to incorporate optimised internal features within the chamber.

Preferably the 3D printed cementitious section includes at least one recess formation lying coincident with an interior cavity within the chamber.

The inclusion of one or more such recess formations within a respective interior cavity advantageously provides a sump facility within the or each interior cavity to collect undesirable fluids and/or other contaminants.

In a still further preferred embodiment of the invention the or each recess formation is surrounded by an inclined formation shaped to urge fluid into the said recess formation.

The inclusion of one or more such inclined formations again leverages the greater manufacturing flexibility provided by 3D printing to incorporate features within the chamber which improve its functionality and/or avoid the need for separate, additional constructions steps.

Optionally the chamber includes at least one internal wall dividing the chamber into a plurality of interior cavities.

The provision of such a plurality of interior cavities desirably extends the functionality of the chamber.

Meanwhile, the external wall and the or each internal wall of such 3D printed chambers have an essentially unitarily formed structure which replaces one or more pre-cast cementitious or plastic internal walls and a cast in situ external wall.

Such unitarily formed external and internal walls beneficially increase the overall speed of constructing chambers of this type by reducing the number of construction steps required. Having unitarily formed external and internal walls also desirably increases the reliability of the chamber of the invention because they avoid the need for joints between separately formed components that are otherwise susceptible to fluid penetration.

The chamber may further include a lifting formation fixedly coupled with at least one internal wall.

Having a lifting formation which is coupled with at least one internal wall of the chamber advantageously permits lifting and moving of the chamber, i.e. via the lifting formation, in a manner that avoids applying loading to, e.g. a 3D printed cementitious base slab which is not optimally configured to withstand such loading.

Preferably the chamber has a plurality of internal walls interconnected by a support column and the lifting formation is fixedly secured to the support column.

The inclusion of such a support column, and the fixed securing of the lifting formation thereto, desirably helps to ensure that the chamber as a whole, and the internal walls and support column in particular, have sufficient tensile strength to permit lifting and moving of the chamber via the lifting formation.

Optionally the external wall includes at least one elongate reinforcing member extending therearound to define a closed reinforcing loop.

Including one or more such reinforcing members helps to enhance further the robustness of the chamber, e.g. when being lifted and moved, and in particular to reduce the risk of brittle failure occurring when a load is accidentally applied to the chamber during such manoeuvring.

According to a second aspect of the invention there is provided a method of constructing a cementitious chamber comprising the step of 3D printing an external wall having a first portion with a first wall thickness and a second portion with a second wall thickness greater than the first wall thickness, the second portion being positioned in-use in a higher loading region than the first portion.

The method of the invention shares the benefits of the corresponding features of the chamber of the invention.

It will be appreciated that the use of the terms "first" and "second", and the like, in this patent specification is merely intended to help distinguish between similar features, and is not intended to indicate the relative importance of one feature over another feature, unless otherwise specified.

Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, and the claims and/or the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and all features of any embodiment can be combined in any way and/or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner.

There now follows a brief description of preferred embodiments of the invention, by way of non-limiting example, with reference being made to the following drawings in which: Figure 1 shows a schematic, cross-sectional, elevational view of a 3D printed cementitious chamber according to a first embodiment of the invention; and Figure 2 shows a plan view from above of the chamber shown in Figure 1.

A 3D printed cementitious chamber according to a first embodiment of the invention is designated generally by reference numeral 10, as shown in Figure 1. The first embodiment cementitious chamber 10 is a fluid distribution chamber for use in wastewater treatment, although other types of chamber are also possible. One such other type of chamber is a manhole chamber (which are sometimes also known as "inspection chambers") that allows for the inspection of underground infrastructure as well as, in some instances, access to that infrastructure by engineering personnel.

The fluid distribution chamber 10 shown has an external wall 12 which defines a circular perimeter of the distribution chamber 10. Other perimeter shapes are also possible however.

The distribution chamber 10 shown also includes three internal walls 14 which divide an interior 16 of the distribution chamber 10 into three interior cavities 18, that are essentially identical to one another. In other embodiments of the invention (not shown) the distribution chamber may include fewer than or more than three internal walls, and hence fewer than or more than three interior cavities. Moreover, such interior chambers need not necessarily be identical to one another. Still further 3D printed cementitious chambers according to the invention may have no internal walls at all, and so essentially have only an external perimeter wall.

Returning to the embodiment shown, the three internal walls 14 intersect at, and are interconnected by, a support column 20. In the embodiment shown the support column has a hollow circular cross-section which defines an elongate cylindrical cavity 22 surrounded by a cylindrical wall 24, although this need not necessarily be the case. Additionally, while the support column 20 shown is centrally located within the interior 16 of the distribution chamber 10, it may be positioned differently in other embodiments of the invention.

Each of the external wall 12, the three internal walls 14, and the cylindrical wall 24 of the support column 20 is formed from 3D printed layers 26 of a cementitious composition which may be, or include, one or more of a cement, a mortar and/or a concrete. Typically, such a printed cementitious composition, once fully dried, has a compressive strength of about 40 N/ mm2 and a tensile strength of about 4 N/mm2.

In this context, 3D printing is an additive process in which layers of material, i.e. a cementitious composition, are built up to create a 3D part. One type of printer that is suitable for such 3D printing is CyBe Construction's 3D concrete printer, although other 3D printers may also be used.

The 3D printing may take place nearby to the proposed installation site and the completed distribution chamber 10 be craned into position. The completed chamber, e.g. a fluid distribution chamber 10, may be partially or fully submerged below ground, e.g. to a depth of about 1.4m, although this is not essential. A mobile platform, such as a flat bed vehicle, to support the 3D printer and which includes a crane to move the completed chamber into position is one possibility. Alternatively, the chamber, e.g. distribution chamber 10, may be 3D printed off-site and transported to site ready for installation.

In the embodiment shown, each 3D printed cementitious layer 24 is approximately 20mm deep, i.e. each layer has a height of approximately 20mm, and is approximately 40mm wide. Additionally, two adjacent layers 24 lying next to one another are used to form each of the external wall 12, the internal walls 14 and the cylindrical wall 24 of the support column 20, such that each said wall 12, 14, 24 has an overall width of approximately 80mm. Other embodiments of the distribution chamber (not shown) may include printed cementitious layers of a different depth and/or walls of a different overall width.

As best shown in Figure 1, the external wall 12 has a first portion 28 that has a first wall thickness 30 of approximately 80mm. Additionally, the external wall 12 has a second portion 32 which has a second wall thickness 34.

The second wall thickness 34 is greater than the first wall thickness 30, and preferably is at least 1.5 times greater than the first wall thickness 30. In the particular embodiment shown, the second wall thickness 34 is twice as great as the first wall thickness 30, such that the second wall thickness 34 is approximately 160mm.

Different first and second wall thickness are possible, however.

In use, the second portion 32 of the external wall 12, i.e. the portion with a second wall thickness 34, is positioned in a higher loading region than the first portion 28.

More particularly, in the embodiment shown the second portion 32 lies, in use, below the first portion 28. In this way when the fluid distribution chamber 10 is being used, and hence each interior cavity 18 thereof is retaining a fluid, the second portion 32 is positioned in a region which experiences a greater pressure from the fluid above and is therefore subjected to a higher loading, i.e. higher tensile loading in the arrangement shown, than the pressure and resulting loading imparted on the first portion 28.

In other embodiments, e.g. where the 3D printed cementitious chamber is a manhole chamber, the pressure exerted on the second portion of external wall may come from a mass of earth or other building material which surrounds the manhole chamber. In such an arrangement the second portion similarly experience a greater pressure, and thus is subjected to a higher loading (albeit a higher compressive loading) than the loading applied to the first portion.

In addition to the foregoing, the second portion 32 of the external wall 12 has a height which is less than 10% of the overall height of the external wall 12.

In that regard, in the embodiment shown the external wall 12, internal walls 14, and cylindrical wall 24 each has a height which is as close as possible to 2.4m. Additionally, and by way of exemplary example, the internal diameter of the external wall 12, i.e. the diameter of the interior 16 of the distribution chamber 10, is approximately 1.8m. These heights and internal diameter may differ, however, in other embodiments of the invention.

Returning to the illustrated embodiment, the first and second portions 28, 32 of the external wall 12 have a height ratio of 11:1, such that for the external wall 12 shown with an overall height of approximately 2.4m, the first portion 28 has a height of approximately 2.2m and the second portion 32 has a height of approximately 0.2m. In other embodiments of the invention (not shown) the second portion of the external wall may have a height greater than or smaller than 0.2m.

In still further other embodiments of the invention (not shown), the external wall of the cementitious chamber may, in use, extend substantially horizontally rather than vertically. In such arrangements, and in particular where such a horizontally-orientated chamber is intended to retain or carry a fluid, the second portion of the external wall with the greater second wall thickness may similarly lie below the first portion due the fluid exerting a downwards pressure.

Returning to the fluid distribution chamber 10 shown, it additionally includes a cementitious base slab 36 upon which the external, internal and cylindrical walls 12, 14, 24 sit.

In the embodiment shown, the cementitious base slab 36 is a 3D printed cementitious slab 38, and more particularly is a slab formed from 3D printed layers 26 of, preferably, the same cementitious composition from which the external, internal and cylindrical walls 12, 14, 24 are formed, i.e. a composition that is, or includes, one or more of a cement, a mortar and/or a concrete. Such a 3D printed cementitious slab 38 has a thickness of approximately 75mm, although this need not necessarily be the case. In other embodiments (not shown) the cementitious base slab may include both a 3D printed cementitious section and a reinforced concrete section.

In still further embodiments of the invention (not shown), the base slab may instead only include a reinforced concrete section upon which lies a 3D printed cementitious layer. Typically such a 3D printed cementitious layer has a thickness of about 50mm, although this may vary in different embodiments. Also, such a reinforced base slab may include a plurality of anchor points, and more particularly preferably two pairs of symmetrical anchor points which provide lifting points for the base slab and walls sat thereupon.

Returning to the distribution chamber 10 shown with a 3D printed cementitious base slab 38, the 3D printed based slab 38 includes three recess formations 40, each which lies coincident with a respective one of the plurality of interior cavities 18 within the distribution chamber 10. In addition, each recess formation 40 is surrounded by an inclined formation 42 (not shown in the figures for reasons of simplicity) that is shaped to urge fluid into the said recess formation 40. Also, each recess formation 40 preferably has a diameter of 200mm and a depth of 25mm, although these may vary in other embodiments.

As well as the foregoing, the fluid distribution chamber 10 shown further includes a lifting formation 44 which is fixedly coupled with each of the internal walls 14 via the support column 20.

More particularly, in the embodiment shown, a lifting member 46 in the form of a lifting eye 48 (although other types of lifting member may be used instead) is coupled with a retention formation 50 in the form of a U-shaped bar 52 (although other types of retention formation may be used) that lies within the cylindrical cavity 22 of the support column 20 and which, in turn, is fixedly retained within the cylindrical cavity 22, e.g. by at least one (and preferably four) securing members 54 in the form of respective reinforcement bars 56 (although other types of securing member are also possible).

The securing members 54, i.e. the reinforcement bars 56, are themselves bedded into the printed layers 26 of the cylindrical wall 24 of the support column 20 and thereby act as shear keys. Preferably the cylindrical cavity 22 is infilled with a mortar mix 58 or other cementitious mix to further retain the securing members 54, i.e. the reinforcement bars 56, and thereby retain the retention formation 50, i.e. the U-shaped bar 52, within the cylindrical cavity 22. Accordingly the lifting member 46, i.e. the lifting eye 48, defines a lifting formation 44 which is fixedly coupled, via the retention formation 50 and at least one securing member 54 which are secured to the support column 20, with each of the internal walls 14 of the distribution chamber 10.

Additionally, the external wall 12 of the fluid distribution chamber 10 includes twelve elongate reinforcing members 60 in the form of respective circular loops 62 of metal bar which extend around the external wall 12 to define respective closed reinforcing loops. Other types of material may be used for one or more of the reinforcing members and they may have a different loop shape. In any event, for a distribution chamber 10 having walls 12, 14, 24 approximately 2.4m high the reinforcing members 60 preferably are spaced about 200mm from one another. Other embodiments of the invention (not shown) may, however, include fewer than or more than twelve reinforcing members and such reinforcing members may be spaced differently from one another.

In use, preferably a 3D printer, e.g. a 3D concrete printer, is moveably positioned close to a proposed installation site for a cementitious chamber, e.g. a fluid distribution chamber 10, of the invention and carries out the steps of 3D printing the base slab 38, external wall 12, three internal walls 14 and the cylindrical wall 24 of the support column 20, with the second portion 32 of the external wall 12 having a second wall thickness 34 which is twice as thick as the first wall thickness 30 of the first portion 28 of the external wall 12.

Such a 3D printed distribution chamber 10 may then be moved into the exact position of installation, e.g. by being lifted via the lifting formation 44, i.e. the lifting eye 48, fixedly coupled with the three internal walls 14 thereof whereby the second portion 32 of the external wall 12 is positioned in a higher loading region than the first portion 28.

Claims

CLAIMS: 1. A 3D printed cementitious chamber comprising an external wall having a first portion with a first wall thickness and a second portion with a second wall thickness greater than the first wall thickness, the second portion being positioned in-use in a higher loading region than the first portion.
2. A chamber according to Claim 1 wherein the second wall thickness is at least 1.5 times greater than the first wall thickness.
3. A chamber according to Claim 2 wherein the second wall thickness is twice as great as the first wall thickness.
4. A chamber according to any preceding claim wherein the second portion lies in-use below the first portion.
5. A chamber according to Claim 4 wherein the second portion of the external wall has a height which is less than 10% of the overall height of the external wall and preferably the first and second portions of the external wall have a height ratio of at least 11:1.
6. A chamber according to any preceding claim further comprising a cementitious base slab upon which the external wall sits.
7. A chamber according to Claim 6 wherein the base slab is or includes a reinforced concrete section upon which lies a 3D printed cementitious layer.
8. A chamber according to Claim 7 wherein the base slab includes a plurality of anchor points.
9. A chamber according to any of Claims 6 to 8 wherein the base slab is or includes a 3D printed cementitious section.
10. A chamber according to Claim 9 wherein the 3D printed cementitious section includes at least one recess formation lying coincident with an interior cavity within the chamber.
11. A chamber according to Claim 10 wherein the or each recess formation is surrounded by an inclined formation shaped to urge fluid into the said recess formation.
12. A chamber according to any preceding claim including at least one internal wall dividing the chamber into a plurality of interior cavities.
13. A chamber according to Claim 12 further including a lifting formation fixedly coupled with at least one internal wall.
14. A chamber according to Claim 13 having a plurality of internal walls interconnected by a support column and wherein the lifting formation is fixedly secured to the support column.
15. A chamber according to any preceding claim wherein the external wall includes at least one elongate reinforcing member extending therearound to define a closed reinforcing loop.
16. A method of constructing a cementitious chamber comprising the step of 3D printing an external wall having a first portion with a first wall thickness and a second portion with a second wall thickness greater than the first wall thickness, the second portion being positioned in-use in a higher loading region than the first portion.