Modular artificial reef structure

Abstract

Artificial reef structure unit comprising a body having a primary connecting profile for assembling the unit to the primary connecting profile of another reef structure unit, and the body also having two or more secondary connecting profiles for assembling the unit to secondary connecting profiles of two or more reef structure units.

Description

Modular Artificial Reef StructureField of Invention

[0001] The present invention relates to units, assemblies and methods for modularly constructing artificial reef structures particularly, but not exclusively, for installation in marine habitats for commercial and research applications.Background

[0002] Marine habitat infrastructure is available in a variety of configurations and sizes, and is usually adapted for applications including coastal protection, eco engineering of marine infrastructure, coral farming, marine animal farming, marine biology research and repair, aquarium installations and even art installations. Such infrastructures are designed to be submerged in an aquatic environment, whether natural or artificial, their design will be dependent on the targeted application and sympathetic to the environment.

[0003] For example, concrete reef structures have been designed to provide shelter and protection to fish where fish habitats have been destroyed or eroded. Other structures promote the growth of marine animals for farming, such as abalone and oysters, or for plants including seaweed. Others still are installed in reefs to foster regeneration of coral and other marine life.

[0004] The nature of marine habitat infrastructure requires the structure to be made of a durable and usually heavy material so as to properly anchor in a submerged position under water and resist movement from tidal currents and storms. Necessarily these structures will require installation by barge crane, which can be expensive. Smaller modular units that can be assembled by divers underwater have been used to replace craning large units into position. This has benefits but the assembly process can develop complexities when assembling in water. Furthermore, transportation of any of marine habitat infrastructure can be costly due to its weight in a shipping container.

[0005] The present invention is provided with the above drawbacks in mind in designing and manufacturing an artificial reef structure.Summary of the Invention

[0006] In a first aspect the invention provides an artificial reef structure unit comprising a body having a primary connecting profile for assembling the unit to the primary connecting profile ofanother reef structure unit, and the body also having two or more secondary connecting profiles for assembling the unit to secondary connecting profiles of two or more reef structure units.

[0007] The reef structure units can preferably be referred to as ‘similar’ reef structure units. By ‘similar’ it is intended to mean that the units have features for complementarily connecting to each other. The similar units themselves may be exact replicas, namely having the same configuration. Or the similar units may be configured differently but still have complementary connecting features.

[0008] For example, there may be an ‘A’ type structure unit that connects with other same A type structure units. There may alternatively or additionally be provided ‘B’ type units, that are configured or shaped differently from A units but can connect with A units. The B units will have complementary primary connecting profiles and secondary connecting profiles with the A units. Alternatively to being shaped differently, the B units may have the same shape as the A units, but may only differ in the orientation and / or configuration of the primary and / or secondary connecting profiles. This allows for similar or same shaped A and B units to interconnect in a different orientation compared to interconnected A units or interconnected B units.

[0009] In a further embodiment there may be more structure types that can be interconnected with each other. For example, there may be a ‘C’ type structure that could be interconnected with either the A or B structures through their respective primary connecting profiles or secondary connecting profiles. A ‘D’ type structure may also be provided, and so on.

[0010] In a second aspect the invention also provides an artificial reef structure assembly comprising two artificial reef structure units, wherein the units are connected to each other in an inverted relationship at their respective primary connecting profiles.

[0011] The structure units and the more complete assembly formed by two units inversely joined together, can be modularly used in a repeatable fashion to create large three-dimensional artificial reef lattice structures intended for permanent installation in various aquatic environments, and advantageously can be used for the promotion of marine life. The lattice structures can be formed in endless combinations by repeating interconnecting structure assemblies in a stable overall system.

[0012] In a preferred embodiment, the body of the structure units has a width that is greater than a height. This provides an advantage of the structure assemblies having a wide surfacearea that promotes growth of coral and provides a complex habitat for fish with large overhangs and swim throughs.

[0013] In one embodiment one or more surfaces of the structure unit body is provided with a ridge surface profile comprising a series of ridges and channels forming a complex surface geometry. An effect of the ridges is that they maximise the effective surface area of the unit for promoting growth of marine species such as coral and algae. The ridges preferably comprise an organic pattern that gently curves and can be provided as a fine pattern or a more course pattern. In a more specific embodiment, the ridges can be formed in continuous, or semi- continuous, curvilinear lines extending between one or more of the primary and / or secondary connections or any one of the connections and an outer edge of the unit. These patterns encourage the natural flow of water through the channels between the ridges to clean the channels from sand, dirt and algae in the channels.

[0014] In a specific embodiment, in side profile the body of the structure unit is shaped to have a raised centre with respect to outer regions of the body. Outer regions of the body include enlarged ends, also defined as petal portions extending radially downwardly from the raised centre. In one embodiment, the enlarged ends comprise three petal portions.

[0015] The primary and secondary connecting profiles preferably have both protruding and receiving elements, and specifically correspondingly engaging protruding and receiving elements. In one embodiment, the primary connecting profile is configured to be the same connecting profile across all units. Namely, the primary connecting profile will have the same interconnecting structure on unit A, unit B, unit C, etc. In this way all units can be interconnected with any other unit, including its own unit type, by aligning the units with respect to each other.

[0016] Additionally, the primary connecting profile may be configured unidirectional so that it can only engage with another primary connecting profile in one orientation. Depending on how the primary connecting profile is provided, or formed, on a unit will determine if two interconnecting units are provided in phase with each other, e.g. aligned at 0°, or out of phase with each other by 180°. For instance, two units having primary connections formed in the same directional orientation may be interconnected out of phase. Whereas two units configured with primary connections in different directional orientations could be designed to be interconnected in phase. Different orientations is achieved by the primary connection having a unidirectional connecting surface, namely a connection that can only be engaged in one way.

[0017] In this embodiment, the secondary connecting profile may be configured to be the same across all units to provide an alternative, but compatible, connection location for the units. The same unit type or different unit types are therefore also interconnectable at their respective secondary connecting profiles. The secondary connecting profile may be unidirectional or bidirectional.

[0018] The primary connecting profile defines a primary connection that is preferably located at a centre of the structure unit. In one embodiment the centre may be a raised centre of the structure unit and the primary connecting profile is positioned to face outwardly of the raised centre, namely facing upwards when the centre is raised relative to a horizontal reference plane.

[0019] In an embodiment, the secondary connecting profiles define secondary connections that are radially spaced from the primary connection, so that the secondary connections are preferably laterally displaced from the primary connection. Furthermore, the secondary connections face oppositely to the primary connection. In other words, the primary connection has a connection surface that faces an opposite direction to connection surfaces of the primary connections. Therefore, in a particular embodiment of the reef structure unit, the primary and secondary connections face in opposite directions and the secondary connections are relatively displaced from a primary connecting axis of the unit along which the primary connection lies. In an embodiment, the primary connecting axis is also a central axis of the unit. The relative placement of the primary and secondary connections ensure there is no interference between connecting units. When two structure units are connected through the primary connections, there will be no interference for a third structure unit being connected to one or the other two structure units at a secondary connection.

[0020] Further in an embodiment of the relative placement of the connections, where the primary connection is located on a top of the structure unit the secondary connections will be located on an underside of the structure unit. In the embodiment where the structure unit is formed to have petal portions, the secondary connections may be located on the underside of each petal portion at the enlarged end, and therefore axially displaced from the primary connection. Each unit has at least two secondary connections, and in a preferred embodiment there are three secondary connections, one on the underside of each petal portion.

[0021] Two structure units may be inversely positioned to each other so that they are attached at their respective primary connections to form a structure assembly. Attachment may be by fastening mechanically, for example, with a long screw bolt, adhesively, or a combination of mechanical and adhesive / chemical fasteners. In the embodiment where the structure units arewider than they are high, the primary connections are for inversely attaching two structure units to form a structure assembly having two shelves, where each self is formed from a width of the unit. And in the embodiment where the units have a raised centre with outward petals, the upper shelf will have a slightly upward flare, and the lower shelf has a slightly downward flare.

[0022] In an embodiment, the primary connection, includes an upstanding protrusion and a matching adjacent recess. The protrusion and the recess have complementary similar profiles to enable the protrusion of one unit to locate into the complementary recess of the other. Such a connecting profile enhances stability and strength in the connection between two units. In one embodiment the plan profile of the primary connection is circular or elliptical, where half of the circular or elliptical profile comprises the upstanding protrusion and the other half is the recess, where an orthogonal wall separates the protrusion from the recess. The primary connection may be a solid connection providing for strong lateral resistance. A fastening bolt with nut can be located centrally of the primary connection along the wall in a bolt recess provided in the wall.

[0023] The secondary connection may, in one embodiment, have a sinusoidal curve profile. The sinusoidal peak of a secondary connection on a first structure unit is configured to locate in the sinusoidal trough of the secondary connection of another structure unit. Accordingly, the sinusoidal curve profile of the secondary connection will have corresponding curves so that one fits in the other thereby engaging two structure units. Mechanical and / or adhesive fasteners can be used to fixedly fasten two structure units through their secondary connections.

[0024] Typically, the two structure units engaged through the secondary connections will not be the same two structure units that are engaged through their primary connections. In other words, two structure units will preferably only engage by way of their respective primary connections or their respective secondary connections. The relative placement of the primary and secondary connections mean that a first unit will receive a second unit at the first unit’s primary connection, and can only receive a third unit at the first unit’s secondary connection. Accordingly, a larger lattice structure may be assembled. In a preferred embodiment the secondary connections are used to connect together two structure assemblies, where each structure assembly comprises two structure units connected to each other at their respective primary connections.

[0025] It is understood that the primary and secondary connections described herein are not limited to the descriptions provided but may alter in profile, configuration and strength of interconnection. However, it is noted the same or similar structure unit type is repeatable to connecttogether through the primary and secondary connections in a variety of desired and endless configurations.

[0026] One aspect of the reef structure includes removable end caps. End caps are preferably provided with a secondary connection on an underside for attaching to a secondary connecting profile on any one of the reef structure units or reef structure assemblies. The end caps are also provided with ridge surface profile to promote the growth of marine biology, including coral.

[0027] According to the present invention there is also provided a method of manufacturing an artificial reef structure unit including: printing a master mould using additive manufacturing with a first mould material; creating an upper inverse mould by pouring a second mould material on the master mould; creating a lower inverse mould by pouring the second mould material on the master mould; moulding upper and lower production moulds by applying a third mould material onto each upper and lower inverse moulds to create a rigid upper production mould and a rigid lower production mould, which define the two halves of a complete production mould; connecting the upper and lower production moulds to form a hollow interior; pouring a setting mixture into the hollow interior through a pouring opening in one of the upper or lower production moulds and casting the artificial reef structure unit in the complete production mould.

[0028] In one embodiment the master mould is printed as an entire unit representing an artificial reef structure unit. In an alternative embodiment the master mould comprises an upper master mould and a lower master mould representing an upper portion of the reef structure unit and a lower portion of the reef structure unit, respectively.

[0029] In a preferred embodiment, the method includes printing a ridge pattern on surface of the initial mould.

[0030] The method may include, in one embodiment, using a polyester such as polylactic acid (PLA) as the first mould material. In another embodiment the second mould material may be silicone. In a further embodiment, the third mould material may be fiberglass. Preferably, the setting mixture is a concrete mixture or a ceramic mixture.

[0031] The pouring opening may be provided centrally of the upper production mould.

[0032] In another embodiment, the method of manufacturing an artificial reef structure unit involves manufacturing a reef structure unit having the features of a reef structure unit as described above.Brief Description of the Figures

[0033] In order that the invention be more clearly understood and put into practical effect, reference will now be made to one or more preferred embodiments in accordance with the present invention. The ensuing description is given by way of non- limitative example only and is with reference to the accompanying drawings, wherein:Figure 1 illustrates an upper isometric view of an artificial reef structure in accordance with an embodiment of the present invention constructed from connecting four reef structure assemblies;Figures 2a to 2d respectively illustrate in upper isometric view, plan view, front and side view, a single reef structure assembly constructed from connecting two reef structure units;Figure 3a is an exploded isometric view of the reef structure units connecting to form a reef structure assembly, whereas Figures 3b to 3d illustrate the connected assembly in isometric view, side view and plan view respectively, but without showing a ridge surface pattern on the units;Figures 4a to 4h respectively illustrate the following views of a single reef structure unit: upper first isometric view, upper second isometric view, plan view, first side view, second side view, third side view, underneath isometric view and underneath view;Figure 5 is a process chart showing the process of manufacturing a reef structure unit;Figure 6a and 6b are respectively side and upper exploded isometric views of a reef structure unit formed in a mould;Figure 7 is an exploded isometric view of a reef structure showing the interconnection between the reef structure assemblies;Figure 8a is an exploded isometric view of a reef structure showing the interconnection between the reef structure and the end caps;Figure 8b is a similar figure to Figure 8a but illustrating the components with the ridge surface pattern;Figures 9a to 9f respectively illustrate the following views of a single end cap: plan view, upper isometric view, right side view, rear view, front view and underneath view;Figures 10a to 10h respectively illustrate the following views of a single reef structure unit according to a second embodiment of the invention: upper first isometric view, plan view, upper second isometric view, first side view, second side view, third side view, underneath isometric view and underneath view;Figure 11a is an exploded isometric view of two reef structure units of Figures 10a to 10h connecting to form a reef structure assembly;Figures 11 b to 11 e illustrate the connected reef structure assembly of Figure 11 a in isometric view, first side view, second side view and top view respectively, where Figures 11c, 11d and 11e also illustrate a ridge surface pattern on the units;Figure 12a is an exploded isometric view of a reef structure formed by interconnecting multiple reef structure assemblies shown in Figures 11b to 11d; andFigure 12b is an unexploded isometric view of the reef structure of Figure 12a.Detailed Description:

[0034] The description that follows and the drawings illustrate an embodiment of a modular artificial reef structure and its components in accordance with the invention. The reef structure described herein exhibits advantages over known artificial marine infrastructure in that it provides a stable structure capable of being easily constructed either above or below water yet also provides a complex eco-habitat for marine life.

[0035] Figure 1 illustrates an assembled artificial reef structure 10 as a complete system comprising reef structure units 20 modularly coupled together to form reef structure assemblies25 that are, in turn, modularly interconnected with other assemblies 25 to form the complete system reef structure 10. End caps 50 are also shown connected to outer regions of the structure units 20.

[0036] Reef structure 10 is an artificial three-dimensional lattice structure that can be easily installed underwater by divers, usually at 3-7m of water, removing the need for heavy machinery such as barge cranes. The modularity of the system provides the option, as desired, of assembling the structure 10 underwater, unit by unit or assembly by assembly, or to construct the structure on land before lowering it into position underwater using machinery. The interconnection of the structure’s components is such that the resulting lattice forms a very strong structure that can withstand underwater surges from strong storms and also provide safe shelter for marine life.

[0037] An advantage of the presently described system is that the core construction pieces (putting aside the end caps 50) are formed from a single building unit 20 that can be modularly connected to replicated units 20 to form an entire reef structure 10 in endless arrays.

[0038] The reef structure 10 illustrated in Figure 1 is constructed from multiple interconnected structure assemblies 25 and end caps 50. A reef structure assembly 25 is illustrated from various angles in Figures 2a to 2d and Figures 3a to 3d, while end caps 50 are illustrated in Figures 9a to 9f. Figures 3a to 3d do not show the surface detail on the structures 25 that are shown in Figures 2a to 2d, which have been removed for clarity. It is, however, understood that surface detail may differ in pattern including not having any surface detail.

[0039] Figures 4a to 4h illustrate various views of the reef structure unit 20. Unit 20 has a substantially planar body 21 with an organic shape sympathetic to the aquatic environment in which it is intended to be installed. The width of the unit’s body 21 is generally greater than its height. In side profile the unit is shaped to have a raised centre 26 relative to a horizontal reference plane H (when viewed facing upwardly as shown in Figures 4a to 4f). Extending radially and downwardly from the raised centre 26 are three petal portions, or petals, 22 with enlarged ends 23. On the opposite side of the unit’s body to the raised centre 26 is a concavity 27 formed by the downward depending profile of the petals 22 from the raised centre. An underside of the petals are substantially level and act as feet for support.

[0040] The entire periphery and side profile of the reef structure unit 10 is organically curved and undulating, simulating natural geometries found in marine rock and coral structures.

[0041] Each structure unit 20 is provided with one primary connecting profile 30 (also referred to as a ‘primary connection’) and multiple secondary connecting profiles 40 (also referred to as ‘secondary connections’). In the example described herein, the primary connection 30 is centrally located on the unit and specifically at the raised centre 26, and has a primary connection surface 16 facing upwardly. Furthermore, there are three secondary connections 40 in the embodiment described. Each secondary connections is located on the underside of the petals 22 (and therefore participate in acting as feet). The secondary connections 40 have secondary connection surfaces 17 that face downwardly, in an opposite direction to the primary connection surface 16. It is possible to provide fewer (two) or more secondary connections (more than three), however the selection of secondary connections will be dependent on the size of the unit 20 and its overall shape.

[0042] Primary connection 30 and secondary connections 40 are axially displaced from each other so as to avoid multiple interconnected assemblies from interfering with each other. Figure 4f illustrates primary connection 30 centrally located on the unit 20 along a central axis X. Secondary connections 40 are displaced axially from the X axis. In this way, a greater structure can be modularly built by connecting reef structure units 20 into assembled pairs of units - reef structure assemblies 25 - and then assembling multiple assemblies 25 to from an artificial reef structure 10.

[0043] Each primary and secondary connection is configured so as to be able to connect onto a replica of itself. In other words, the connections are symmetrically formed having both protruding and receiving elements so that when two primary connections are brought together, or two secondary connections are brought together, the like-connections mate and engage. The connecting profiles of the primary and secondary connections are different so that only primary meshes with primary and secondary meshes with secondary. Accordingly, one structure unit 20 can only connect to one other structure unit 20 via their primary connections 30 on an upper facing side, but one structure unit 20 can connect to multiple structure units 20 through their secondary connections 40 at a lower facing side.

[0044] As best shown in Figures 3a and 4a to 4c, primary connection 30 is a circular or elliptical connection having a semi-circular upstanding protrusion 31 (which is the protruding element) and a correspondingly matching-shaped primary recess 32 (which is the receiving element). A shoulder 34 forms a wall that divides the protrusion 31 and the recess 32. When two primary connections 30 are brought together the upstanding protrusion 31 on one of the primary connections inserts into the primary recess 32 of the other primary connection in a concealedlap joint-type connection. The primary connection 30 is cast with the unit 20 and forms a solid connection with another unit 20 providing resistance against lateral forces. A central primary bolt hole 33 in the centre of the primary connection is adapted to receive a fastening bolt that can be used to mechanically secure together two engaged units 20. Since it is centrally positioned, bolt hole 33 forms along half the shoulder 32 of one unit 20 and half the shoulder 32 of the other unit 20 as a semi-hole in each shoulder. The semi-holes formed in each unit make up bolt hole 33.

[0045] The secondary connections 40 are also formed to have a protruding element and a corresponding receiving element. In the embodiment shown the secondary connection has a sinusoidal curve profile when viewed from the side (as seen inf Figures 4d to 4g), where the sinusoidal curve runs in the radial direction of the unit 20. The sinusoidal peak on one engaging secondary connection (defined as the protruding element) meshes to fit into the sinusoidal trough (defined as the receiving element) of another engaging element. Necessarily, the two secondary connections will be oppositely facing to each other. The two structure units are thereby interlocked radially. Bolt holes 33 provided at each secondary connection stably fix the units 20 together. Adhesives fasteners, such as marine epoxy, can also be used to fasten the units at the secondary connections.

[0046] As discussed, structure assembly 25 is constructed by connecting together two structure units 20 in an inverted relationship at the primary connections 30 to form a structure assembly having two shelves of petal portions 22, where an upper shelf 38 has a slightly upward flare and the lower shelf 39 has a slightly downward flare. The exploded view of Figure 3a shows that inter-connection relationship. An upper structure unit 20 is positioned upside down relative to the lower structure unit 20. The units, now facing each other, connect at their primary connections 30.

[0047] Because a structure assembly 25 comprises two inverted, oppositely facing structure units 20, two assemblies 25 can engage at their secondary connections 40 where the secondary connections 40 are facing each other. In other words, an upward facing secondary connection 40 on an upper shelf 38 can engage with a downward facing secondary connection on a lower shelf 39. An indication of this arrangement can be seen in Figure 7.

[0048] A three-dimensional lattice structure is formed by completing the secondary connections between already formed reef structure assemblies 25. The resulting structure is illustrated in Figures 1 , 7 (in exploded view), 8a and 8b. The configuration of the structure units 20 and structure assemblies 25, including its planar organic shape and shelf overhangs created by the petal portions 22, provides a large surface area for coral, and other marine animals, to colonise.

[0049] To further increase and maximise the surface area of the reef structure, the units 20 are provided with a ridge surface profile 35, or pattern, comprising a series of ridges 36 and channels 37 forming a complex surface geometry (see Figure 2b). The ridge profile follows a gently sweeping curvilinear path that follows a general radial direction on the upper side 28 and lower side 29 of each unit 20. While the direction of the ridge profile may be adapted as desired, in the embodiment shown, the ridges and channels flow between the centre of the unit’s upper side 28 and / or lower side 29 and extend radially toward the unit’s periphery 24. Also shown in Figures 2a to 2d are ridges and channels that extend between primary and secondary connections 30, 40 and between secondary connections 40 and the periphery 24. The ridge profile 35 extends across the entire upper and lower sides but for the areas of the primary and secondary connections. It is estimated that the surface area of a structure assembly 25 (comprising two connected units 20) could be in the range of 1.0 - 1.5m2, and preferably 1.29 m2.

[0050] The ridge profile 35 encourages self-cleaning by allowing the natural currents of water to flow through the channels and clear sand, sediment and algae. Manual brushing along the channels is also envisaged. This is advantageous for the natural growth of coral recruits to take hold because coral polyps and algae will compete to grow in the same location. Algae is easier to clean off, while coral will continue to grow. Another potential advantage of the ridge profile 35 is in coastal protection by the generation of eddy currents by the undulating ridges 36 and channels 37.

[0051] End caps 50 are illustrated in Figures 9a to 9f and assembled on the reef structure 10 in Figure 1 . Figures 8a and 8b illustrate the end caps in exploded view positioned ready for attachment to structure assemblies 25. End caps 50 are smaller than structure units 20 and are desired to sit on top of the enlarged ends 23 of the petal portions 22. The end caps are also provided with a ridge profile 35 of ridges and channels on an upper side and an under side of the end cap. It is envisaged that the surface area of an end cap could be 0.25-0.50m2, and preferably 0.36m2. End caps 50 only have one secondary connecting profile 40 on underside so as to engage with an upward facing secondary connection 40 on a structure assembly 25.

[0052] End caps 50 are optional but can aesthetically complete the reef structure. A more practical purpose to the end cap is that it can be removed and used for coral transplantation. Coral can be grown directly onto the end caps in a laboratory or research facility. When the coral is of a sufficient size the entire end cap secured with mature coral can be transferred tothe underwater reef structure and attached to a free secondary connection to continue its growth in its natural habitat.

[0053] In the embodiment described herein, the units 20 are moulded in a setting material - either concrete or ceramic and reinforced with steel and composite reinforcing bar. While any kind of concrete or ceramic composition can be used to mould the units, it is envisaged that an ecologically favourable concrete to mould the structure units would provide a lower carbon footprint. Such a so-called ‘eco blend concrete’ would consist of a low carbon material and utilize recycled materials to reduce the cement content while strengthening the unit. Pozzolan materials can also be used to stabilize the surface chemistry. After moulding, each modular unit is cured underwater for a minimum of 7 days and then fully cured for an additional 24 days to meet the required strength tests.

[0054] Ceramics may also be used and, for example, are a suitable material for the end caps 50. It is envisaged that the end caps could be printed using additive manufacturing techniques (3D printing) using natural ceramic material that is fired in a ceramic kiln after printing.

[0055] The reef structure units 20 are each moulded from a rigid complete production mould 42, 43 comprising an upper production mould 42 and a lower production mould 43. Upper and lower production moulds 42, 43 are created from two respectively 3D printed master moulds of the structure unit 20, and specifically from a 3D printed upper master mould and a 3D printed lower master mould. Figure 6a and 6b illustrate the structure unit 20 being removed from the upper production mould 42 and lower production mould 43.

[0056] Figure 5 illustrates the moulding process to create the upper and lower production moulds 42, 43. The process begins with the step of 3D printing an upper master mould 44 and a lower master mould 45. Together, the upper and lower master moulds mate to create the negative form profile of the reef structure unit 20, including primary and secondary connections 30, 40 and the ridge profile 35. 3D printing a mould of the structure unit has the advantage that the fine details in the ridges and channels, and the primary and secondary connections, can be accurately printed and transferred into the master mould. Any suitable material capable of additive printing could be used to create the master moulds 42,43. An example of a suitable material could be a polyester like polylactic acid (PLA).

[0057] While the present embodiment describes two master moulds, one each for an upper portion (or half) of the unit 20 and the lower portion (half) of the unit 20, it is foreseeable that the master mould could be formed as a single negative profile mould of an entire unit 20.

[0058] An inverse mould is then taken of each master mould. An upper inverse mould 46 is created from the upper master mould 44 and a lower inverse mould 47 is created from the lower master mould 45. The inverse moulds can be made of a flexible material, such as silicone, that is poured on the respective master moulds, allowed to cure and then de-moulded. Using the upper and lower flexible inverse moulds, the upper and lower production moulds 42, 43 can next be created. For example, fiberglass may be applied to a silicone inverse mould to create a rigid production mould.

[0059] Reinforcement can be arranged in the mould to provide strength to the unit, particularly around the bolt holes and petal regions. Stainless steel rods and glass or plastics fibres could be used as reinforcement. The upper and lower production moulds 42, 43 are clamped together to form a hollow interior 48 in preparation for moulding the structure unit 20. Bolts (not shown) through clamping holes 49 in the upper and lower productions moulds 42, 43 clamp the moulds together but also form the bolt holes 33 in the finished structure unit 20.

[0060] At the primary connection in the upper production mould, and specifically at the central feature of the protrusion 31 , there is a pouring opening 41 through which the concrete mould mixture is poured into the hollow interior 48. The mixture is poured until it fills the hollow interior and reaches the top of the opening. The mixture is allowed to cure before the production moulds are separated and the cured unit 20 is de-moulded. Curing may take place underwater, but this may not necessarily be a practical option in which case air curing is satisfactory.

[0061] The production moulds 42, 43 are repeatedly used to cast reef structure units. The production moulds are expected to have a lifespan of at least 200 casts, and likely more.

[0062] A second embodiment of a reef structure unit is illustrated in Figures 10a to 12b. The first embodiment of reef structure unit 20 shown in Figures 1 to 8b can be referred to as a type “A” unit. Accordingly, the unit of the second embodiment is referred to as a type ‘B’ unit, or ‘unit B’ identified by reference number 60. Type A unit 20 and type B unit 60 are substantially similar in appearance - they are both identically-shaped moulded bodies with a central primary connection and three secondary connections on an underside of three outer enlargements. But type A and B units are different in how the primary connection is oriented with respect to the unit shape.

[0063] Comparing the upper isometric views of Figures 10a and 10c of type B unit 60 against the corresponding isometric views of Figures 4a and 4b of type A unit 20, it can be seen that theprimary connection 30 is reversed in B unit 60 to A unit 20. Protrusion 31 of the primary connection is positioned closest to a petal portion 22 in B unit 60, whereas in A unit 20 protrusion 31 is closer to a landing 62 between two petal portions 22. The purpose of the reverse connection is to alter the stacking orientation of the reef structure 10.

[0064] The primary connection can be said to be configured unidirectionally, namely having only one orientation in which corresponding primary connections can be engaged. Depending on how the primary connection is provided, or formed, on a unit will determine if two interconnecting units are provided in phase with each other, e.g. aligned at 0°, or out of phase with each other by 180°. The different orientations is achieved by the primary connection 30 having a unidirectional connection surface 16. One side of the connection 30 has a protrusion 31 and the other side has a complementary recess 32. Only the protrusion 31 will fit into the recess 32, so there is only one direction in which two primary connections can engage.

[0065] In the illustrated embodiment, the secondary connection 40 also has a unidirectional connection surface 17 in that the undulating surface 17 is not quite symmetrical in a planar direction. However, the secondary connection could be made to have a bidirectional engagement by matching the curvature of the surface 17 in opposite directions, namely by providing a symmetrical surface in an X-Y planar direction across the secondary connection surface 17.

[0066] By way of example, when two A units 20 are inversely connected at their primary connection 30 - as shown in Figures 2a to 2d - the orientation of the connected unit profiles are not only inverse of each other but are also rotated 180° - or out of phase - with respect to each other. Because the profile of the three petal unit 20 is asymmetrical, a rotational misalignment of 180° has the result of staggering the unit’s structural features to create a more organically appearing structure. A similar result will be achieved when two B units 60 are inversely connected at their primary connection. However, when an A unit 20 is connected to a B unit 60 to form an assembly 25, the units are stacked in alignment. Namely, the units 20, 60 are inversely positioned to each other but are rotationally aligned in phase at 0°. This results in a different stack orientation as illustrated in Figures 12a and 12b, where the units 20, 60 are in line with each other. Accordingly, providing different types of reef structure units that can be mixed, matched and interconnected allows greater permutations of lattice structures to be achieved, thereby providing a variety of unique artificial reef structures.

[0067] A reinforced concrete base (not shown) can be provided for each structure 10 if a barge is available for installation. The base structures will allow for the modular build above water or below and have rated lifting points to hold the entire assembled structures. The base will have porous holes for material optimisation, sand movement and to avoid mass scouring. A steel base can be provided if concrete is not available on site. Alternatively, the structure can be built underwater, with the units stabilizing the base.

[0068] The units 20 can be formed in any size suitable for constructing a larger modular structure, although consideration should be given to the weight of the units and the practicalities in handling heavier and larger modular units. By way of example only, it is envisaged that an individual structure unit could weigh approximately 50kg

[0069] Given the modular nature of the structure units coupled with the unit’s somewhat concave profile, a practical advantage of the system is that the units can nest in a compact arrangement. This reduces transportation and storage costs.

[0070] The presently described modular artificial reef structure is an elegant and versatile solution to problems encountered with current assemblies of marine infrastructures. Its modularity makes it convenient and relatively easy to assemble, and cost reductions are realised in the transportation and installation of the structure. Furthermore, the structure itself as a three dimensional lattice is optimised for strength, permeability and permanency in that it can withstand natural forces of current surges and storms. The design of the system provides excellent ecological and social outcomes. The system provides a safe habitat for marine animals and other species, and promotes growth of mature coral as well as natural recruits.

[0071] The reef structure itself as a three-dimensional lattice structure optimises the use of material for the volume covered by the structure. Compared to other reef structures covering the same large volume of space, the presently described structure requires a lower embodied energy and therefore a lower carbon footprint.

[0072] It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country.

[0073] In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, theword "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, namely, to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

[0074] It is to be understood that the aforegoing description refers merely to preferred embodiments of invention, and that variations and modifications will be possible thereto without departing from the spirit and scope of the invention, the ambit of which is to be determined from the following claims.

Claims

CLAIMS:

1. Artificial reef structure unit comprising a body having a primary connecting profile for assembling the unit to the primary connecting profile of another reef structure unit, and the body also having two or more secondary connecting profiles for assembling the unit to secondary connecting profiles of two or more reef structure units.

2. The reef structure unit claimed in claim 1 , wherein the primary connecting profile has a primary connection surface that faces in an opposite direction to a secondary connection surface of each secondary connecting profile.

3. The structure unit claimed in claim 1 or claim 2, wherein the primary connecting profile defines a primary connecting axis, and the secondary connecting profiles are displaced from the primary connecting axis.

4. The structure unit claimed in any one of the preceding claims, wherein the primary connecting profile is positioned at a centre of the body and the secondary connecting profiles are positioned offset from the centre of the body.

5. The structure unit claimed in any one of the preceding claims, wherein the body has a width that is greater than a height of the body, and has a centre of the body that is raised with respect to outer regions of the body, wherein the primary connecting profile is located on top of the raised centre.

6. The structure unit claimed in claim 5, wherein the outer regions of the body extend radially downwardly from the raised centre to terminate at enlarged portions, wherein the secondary connecting profiles are located on an underside of the enlarged portions.

7. The structure unit claimed in claim 6, including three enlarged portions, with a secondary connecting profile on the underside of each enlarged portion.

8. The structure unit claimed in any one of the preceding claims, including one centrally located primary connecting profile and three secondary connecting profiles spaced radially from the primary connecting profile.

9. The structure unit claimed in any one of the preceding claims, wherein the primary connecting profile is configured to have a unidirectional connection.

10. The structure unit claimed in any one of the preceding claims, wherein the body is shaped asymmetrically and the primary connection may be oriented with respect to the body to specifically interconnect with another structure unit to create an interconnected two-unit configuration that is in phase or out of phase.11 . The structure unit claimed in any one of the preceding claims, wherein one or more surfaces of the body is provided with a ridge surface pattern comprising a series of ridges and channels forming a complex surface geometry.

12. The structure unit claimed in claim 11 , wherein the complex surface geometry includes curvilinear ridges extending from the primary connecting profile to the secondary connecting profile.

13. The structure unit claimed in claim 11 or claim 12, wherein the complex surface geometry includes curvilinear ridges extending from the primary or secondary connecting profiles to an outer edge of the body.

14. Artificial reef structure assembly comprising two artificial reef structure units as claimed in any one of the preceding claims, wherein the units are connected to each other in an inverted relationship at their respective primary connecting profiles.

15. The reef structure assembly claimed in claim 14, comprising different unit types being connected to each other at their respective primary connecting profiles.

16. A method of manufacturing an artificial reef structure unit including: printing a master mould using additive manufacturing with a first mould material; creating an upper inverse mould by pouring a second mould material on the master mould; creating a lower inverse mould by pouring the second mould material on the master mould; moulding upper and lower production moulds by applying a third mould material onto each upper and lower inverse moulds to create a rigid upper production mould and a rigid lower production mould, which define the two halves of a complete production mould; connecting the upper and lower production moulds to form a hollow interior;pouring a setting mixture into the hollow interior through a pouring opening in one of the upper or lower production moulds and casting the artificial reef structure unit in the complete production mould.

17. The method of manufacturing claimed in claim 16, including printing a ridge pattern on a surface of the master mould.

18. The method of manufacturing claimed in claim 16 or claim 17, including using polylactic acid as the first mould material.

19. The method of manufacturing claimed in any one of claims 16 to 18, including using silicone as the second mould material, and using fiberglass as the third mould material.

20. The method of manufacturing claimed in any one of claims 16 to 19, including using a concrete mixture or a ceramic mixture as the setting mixture.

Images