GB2456011A - Marine platform formed with tetrahedral structures. - Google Patents

Abstract

Marine platforms are used in many applications, in particular relating to oil and gas exploitation. It is proposed that platforms are built to consist of a deck 10, supported by a tetrahedral triangulated structure 1, 2, 4, 5. The tetrahedral triangulated structure provides great strength and offers very little resistance to oncoming waves, taking the deck loads down below the areas most affected by the waves. Supporting the tetrahedral triangulated structure are profiled buoyancy vessels 7 whose air content can be varied to lower or raise the platform according to wave heights, including those of rogue waves. This guarantees the safety of people and equipment on the deck in all weather conditions. The platform may be adapted to support energy conversion systems, equipment, buildings, housing, plantations, heliports, landing strips, harbour quays, swimming pools and beaches.

Description

DESCRIPTION

MARI11E PLATFORM TETRAHEDRAL STRUCTURES This invention relates to the design of marine platforms.

Marine platforms have been used extensively in oil and gas exploitation. They take on many different forms, sometimes single structures containing buoyancy vessels fixed to the deck structure, sometimes steel triangulated structures raising the deck high above the submerged buoyancy vessels. These are generally designed as single stand-alone units, with irregular structures, not intended to grow in any systematic way.

According to the present invention, there is provided a marine platform consisting of a deck, which depending on the platform's destination can carry people, energy conversion systems, equipment, buildings, housing, plantations, heliports, landing strips, harbour quays, swimming pools and beaches, and other facilities, and can accommodate a number of functions, including safety measures in case of an unforeseen disaster, taking the form of floating caissons in the deck, so that portions of the deck, with people and valuable equipment, can float like rafts temporarily until help arrives and lifeboats are deployed, the marine deck resting on a tetrahedral structure, made up of tetrahedra, which present the advantage over many other structures of being construed of four triangular elements with three main edge structural, members each, defining four triangular faces, each structural edge member being always held in position at its end by two other similar members, giving it great strength, the structural members being placed in such a way that the top triangle defining edges are placed horizontally to carry or merge with the deck structure, whilst the further 3 triangle edge structural members descend towards a lower nodal point to which all loads are transferred, the descending members being braced as required by triangular structures placed horizontally at required heights, and near vertically when additional bracing is required, the horizontal triangular bracing triangles linking and stabilising the descending three loadbearing structural members, one set of linking triangles placed at the base linking the nodal points of descending structural members of neighbouring tetrahedra, the whole structure being held rigid by cross triangulation running through the whole structure, the nodal points in turn transferring all their loads to air filled buoyancy vessels consisting of a main cylindrical tank below a conical top offering less resistance to passing wave motion and allowing the whole structure to be raised with less hydraulic resistance, each vessel having a tube running through its centre open to air at the top and descending below the vessel, in which varying amounts of water can be allowed in according to the amount of pressurised air pumped into each vessel so as to vary the buoyancy of the vessels, so that they can exert varying upwards pressure on the nodal points of the tetrahedral structure, causing it to rise or descend, being in its lowest position in fine weather when the waves are small and the deck can be close to the sea surface, allowing for ease of navigation / close to the structure, and at its highest in storm conditions, when the deck can be raised up to the full height of the tetrahedral structure, so that incoming waves are below the deck, and find little resistance from the tetrahedral structure and from the conical tops of the buoyancy tanks, the tetrahedral basic element of one buoyancy tank, its structure and its deck needing neighbouting elements, at least two, not in line, to achieve stability, a variety of geometrical growth assemblies being possible, ranging from linear arrays with terahedra assembled in line, one set having one top structural edge member defining one edge of the assembly on one side, a reversed set filling the triangular voids and defining the other edge, stability achieved by the buoyancy tanks being disposed along two separate lines, to triangular arrays which can be incomplete, where triangular basic elements are assembled corner to corner, three triangles corner to corner create a larger triangle with a triangular void between them, the void benefitting from three horiziontal triangulated structural edge members at deck level, able to carry additional loads, and the 6 descending members of the three tetrahedra needing to be strengthened, but savings achieved by three structuraj descending structural edge members being omitted, the triangular growtth being possibly full, where the interstitial void between corner to corner adjoining tetrahedra is filled with a further tetrahedra, either with its horizontal triangle at the top, or at the bottom of the void, forming a much more rigid structure, a further growth pattern being the hexagonal one, in which tetrahedra are fitted edge to edge, the inner "hexagon" being a hexagon made up of 6 tetrahedra, the second ring also hexagonal, made up of 18 tertahefra, the next hexagonal ring made up of 30 units, the next of 42, then 54 and so on, linear triangular and hexagonal developments each having its own particularities, but allowing for planning of simple complex shaped platforms to suit different requirements, all designed to best resist internal loads and adapt to heavy seas, the edges of the tetrahedral structure and edge buoyancy tanks easy to fit with netting to allow for fish farming, using the plankton brought up from the depths to cool the condensers of ocean thermal energy conversion (OTEC) equipment, the platforms able to provide support to combined wind generators and sea current energy converters, the same combination being possible in shallow seas where the support pole is fixed to the ground, a variety of solar energy conversion systems, OTEC plants and their associated equipment, making it the ideal structure for energy islands, but also for housing islands, military sea posts, leisure and multipurpose islands, and in areas threatened by high waters as shelters on shore or off shore..

Specific embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which:-Figure 1 shows a plan and a view of a horizontally braced tetrahedron.

Figure 2 shows a plan and vierw of a triangular segment made up of 6 tetrahedra Figure 3 shows a front view and a side view of the triangular segment with the top surface deck.

Figure 4 shows a plan of 6 triangular segments linked together to fonn a hexagonal structure.

Figure 5 shows the hexagonal structure in perspective seen from above.

Figure 6 shows a front section and a view of the hexagonal structure.

Figure 7 shows a side section and view throughthe hexagonal structure.

Figure 8 shows tetrahedra growing in a hexagonal way.

Figure 9 shows the terahedra frowing in a linear way.

Figure 10 shows a side view of a combined aerogenerator and sea current energy converter fitted to the triangular segment.

Figure 11 shows a view of the combined aerogenerator and sea current converter seen through the triangular segment.

Referring to Figure I, the plan view illustrates the triangular geometry from which the tetrahedron derives its strength and stability. The top triangle is formed of three structural members, 2. From its three corners descend three load bearing struts, 1, which join at a nodal point, 5.

The top structural members, carrying the deck, are braced by a horizontal triangle, 3.

The downward sloping struts are also stiffened by an intermediary horizontal triangle, 4. Although only one bracing triangle is shown, more could be used if necessary.

The perspective view shows the single tetrahedron, taking the top triangle deck loads down to a single point. The edge members, defining four planes, are all linked in space and triangulated, forming the most rigid of space structures.

Referring to Figure 2, the plan shows the assembly of 6 tetrahedra assembled in a triangular plan, a typical tetrahedron forming the tip of the triangle, with the 3 horizontal members, 2, the 3 downwards struts, 1, the top horizontal bracing triangle, 3, and the intermediary bracing triangle, 4.

The edge sectional view, identical for all three faces, shows the assembled tetrahedral structure, made up of the six tetrahedra, clearly showing the deck, 10, resting on or integrated into the top members, 2, with break points, 11, that would allow various parts to break away and float, when the deck is provided with floating caissons, 12.

The figure makes clear that the weight of the deck is transferred to the top triangle, 2, and then, through the struts, 1, to nodal points, 5, which transfer their loads to the top of the conical sections, 13, of the buoyancy vessels, 7.

The section shows that the minimal tetrahedral structure offers very little resistance to waves flowing through it. The conical sections of the buoyancy units also offer less resistance than the buoyancy units themselves.

The top points of ther buoyancvy units are held in place by a horizontal triangulated structure, 6, whilst their bases are tied together by triangulated struts, 9. From their base protrudes the bottom part of a cylinder, 8, which is continued inside the buoyancy unit to the level of the conical section base, this cylinder serving to allow different amounts of water to penetrate it, according to the controlable air pressure established in the buoyancy units, so allowing the overall buoyancy to be varied, so that the deck can be lowered or raised as required.

Referring to Figure 3, the triangular section is shown from the front and from the side. The front view shows the deck, with structural break lines allowingh caisson flotation, resting on the top triangulated structure, with loads trasferred down to the profiled buoyanct vessels.

The side view shows the same, but from the side, and illustrates the open way to waves provided by the structure and the profiled vessels.

Referring to Figure 4, a plan is shown, without the deck, of 6 triangular segments brought together to form a hexagon shaped platform of much greater area.

Referring to Figure 5, shows a perspective view of the hexagon from above. The 6 triangular segments can be recognised, and the 30 buoyancy units can be clearly seen.

Referring to Figure 6, a frontal view of of the hexagon is shown with the deck, and a perspective without the deck. Boyth illustrating the open way to the waves of the overall structure.

Referring to Figure 7, a side view anf perspective of the hexagon is shown. The structural density of the top layer is evident, as also the triagulated members between the buoyancy vessels, held at their top points,and so prevented from swaying in any way.

Referring to Figure 8, to illustrate planning flexibility of tetrahedra, a manner of growing is illustrated with top members linking side to side, producing a small hexagon plan and perspective, clearly showing the necesity of the base triangulation, to give stability to the tetrahedra, linking their nodal points together.

Referring to Figure 9, a linear manner of tetrahedra growth is shown, to illustrate the ease with which diverse platform plans can be formed, by different tetrahedra dispositions.

Referring to figure 10, a pole is shown fixed back to the main structure at three points, prolonged upwards to hold an aerogenerator, ,21, and prolonged below to hold a trident pivoting around the pole at its end, 22, each arm holding a sea current converter turbine, 23, at its extremity, designed to face the prevailing current, the turbines being held close together, as is possible in water, their energy added to the energy of the aerogenerator, the same combined aerogenrerator and sea current turbines being anchored to ground in shallow waters when the platform is close to land or shallow seas.

Referring to Figure 11, the pole is shown to take the aertogenerator well above the platform, whilst the wave current turbines are below the buoyancy vessels.

The tetrahedral structure is adaptable to most plans, and can be varied in buoyancy according to loads carried. Apart from aerogenerators and wave current energy converters, other energy converter systems can be readily fixed to it. It can carry buildings, housing, heliports, airstrips and whatever planning requirements are necessary. f

Claims (9)

1. MARINE PLATFORM TETRAHEDRAL STRUCTURES

   I A marine platform consisting of a deck, which depending on the platform's destination can carry people, energy conversion systems, equipment, buildings, housing, plantations, heliports, landing strips, harbour quays, swimming pools and beaches, and other facilities, and can accommodate a number of functions, including safety measures in case of an unforeseen disaster, taking the form of floating caissons in the deck, so that portions of the deck, with people and valuable equipment, can float like rafts temporarily until help arrives and lifeboats are deployed, the marine deck resting on a tetrahedral structure, made up of tetrahedra, which present the advantage over many other structures of being construed of four triangular elements with three main edge structural, members each, defining four triangular faces, each structural edge member being always held in position at its end by two other similar members, giving it great strength, the structural members being placed in such a way that the top triangle defining edges are placed horizontally to carry or merge with the deck structure, whilst the further 3 triangle edge structural members descend towards a lower nodal point to which all loads are transferred, the descending members being braced as required by triangular structures placed horizontally at required heights, and near vertically when additional bracing is required, the horizontal triangular bracing triangles linking and stabilising the descending three loadbeanng structural members, one set of linking triangles placed at the base linking the nodal points of descending structural members of neighbouring tetrahedra, the whole structure being held rigid by cross triangulation running through the whole structure, the nodal points in turn transferring all their loads to air filled buoyancy vessels consisting of a main cylindrical tank below a conical top offering less resistance to passing wave motion and allowing the whole structure to be raised with less hydraulic resistance, each vessel having a tube running through its centre open to air at the top and descending below the vessel, in which varying amounts of water can be allowed in according to the amount of pressurised air pumped into each vessel so as to vary the buoyancy of the vessels, so that they can exert varying upwards pressure on the nodal points of the tetrahedral structure, causing it to rise or descend, being in its lowest position in fine weather when the waves are small and the deck can be close to the sea surface, allowing for ease of navigation close to the structure, and at its highest in storm conditions, when the deck can be raised up to the full height of the tetrahedral structure, so that incoming waves are below the deck, and find little resistance from the tetrahedral structure and from the conical tops of the buoyancy tanks, the tetrahedral basic element of one buoyancy tank, its structure and its deck needing neighbouting elements, at least two, not in (a line, to achieve stability, a variety of geometrical growth assemblies being possible, ranging from linear arrays with terahedra assembled in line, one set having one top structural edge member defining one edge of the assembly on one side, a reversed set filling the triangular voids and defining the other edge, stability achieved by the buoyancy tanks being disposed along two separate lines, to triangular arrays which can be incomplete, where triangular basic elements are assembled corner to corner, three triangles corner to corner create a larger triangle with a triangular void between them, the void benefitting from three horiziontal triangulated structural edge members at deck level, able to carry additional loads, and the 6 descending members of the three tetrahedra needing to be strengthened, but savings achieved by three structuraj descending structural edge members being omitted, the triangular growtth being possibly full, where the interstitial void between corner to corner adjoining tetrahedra is filled with a further tetrahedra, either with its horizontal triangle at the top, or at the bottom of the void, forming a much more rigid structure, a further growth pattern being the hexagonal one, in which tetrahedra are fitted edge to edge, the inner "hexagon" being a hexagon made up of 6 tetrahedra, the second ring also hexagonal, made up of 18 tertahefra, the next hexagonal ring made up of 30 units, the next of 42, then 54 and so on, linear triangular and hexagonal developments each having its own particularities, but allowing for planning of simple complex shaped platforms to suit different requirements, all designed to best resist internal loads and adapt to heavy seas, the edges of the tetrahedral structure and edge buoyancy tanks easy to fit with netting to allow for fish farming, using the plankton brought up from the depths to cool the condensers of ocean thermal energy conversion ( OTEC) equipment, the platforms able to provide support to combined wind generators and sea current energy converters, the same combination being possible in shallow seas where the support pole is fixed to the ground, a variety of solar energy conversion systems, OTEC plants and their associated equipment, making it the ideal structure for energy islands, but also for housing islands, military sea posts, leisure and multipurpose islands, and in areas threatened by high waters as shelters on shore or off shore..
2. 2 A marine platform resting on a tetrahedral structure, or pyramidal or other closely related geometric structure, taking the deck load to submerged buoyancy vessels keeping the platform afloat.
3. 3 A marine platform able to support a pole holding a combination of an aerogenerator, with, below the waterline, a sea current energy converter system consisting of one or multiple turbines, the same combination generator being able to be detached from the plafform and anchored to the subsea ground, or with its own floating support, as part of the platform energy system, or on its own, totally independent without the necessity of any platform.
4. 4 A marine platform resting on buoyancy vessels, which can be varied in volume by increasing their diameter or their height, lateral bracing between them making therm act as a single structure.
5. A marine platform resting on buoyancy units whose top end is given a conical profile to offer less resistance to oncoming waves, the top of the conical unit being shaped to merge with the intermediary structure to increase its strength and lessen its hydraulic resistance.
6. 6 A marine platform benefitting from a wave energy collector or attenuator, either linked to the platform structure, or anchored independantly beside it, preferably on the side of prevailing winds and waves, this structure also able to provide additional power by solar energy collectors, able to produce power that can be used for water desalination.
7. 7 A marine platform used to give shelter to populations menaced by rising waters and frequent cyclones and hurricanes, either moored just off-shore, with OTEC facilities, or, without its buoyancy units, and a reduced tetrahedral structure if possible, anchored to ground with provision for rising waters, to serve also as helipad, food and water storage, medical equipment and field hospital facilities.
8. 8 A marine platform comprises a tetrahedral structure which, being able to hinge at its lower nodal points, its horizontal members able to hinge in their middle, the main structural strut members can fold together, for ease of construction but also, so that deployable structures can be built, including military bridges, gangways, cranes, space structures and other such applications. The struts can also fold in their middle to achieve a more compact folding.
9. 9 A marine platform substantially as described herein with reference to figures 1-12 of the accompanying drawings