GB2463476A

GB2463476A - Floating platform supported by an array of flotation columns

Info

Publication number: GB2463476A
Application number: GB0816661A
Authority: GB
Inventors: Kavoss Hashemzadeh
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-09-11
Filing date: 2008-09-11
Publication date: 2010-03-17
Anticipated expiration: 2028-09-11
Also published as: HK1142376A1; GB2463476B; GB0816661D0

Abstract

There is described a floating platform 1 comprising a hull 2 comprising a deck 3 and a side wall 4, which may be in the form of a downwardly-open box-like structure The platform further comprises a plurality of flotation columns 5 arranged within the box-like structure with their axes perpendicular to the deck of the hull. The flotation columns are joined to each other by means of complementary formations (6, 7, Fig 3), which extend along the lengths of the respective flotation columns. The flotation columns may be circular in transverse section, or may be polygonal. The hull may be subdivided into sections by transverse walls, and flotation columns may be provided in only some of the sections. The flotation columns may be sealed at one end, or at both ends.

Description

Floating Platform The present invention relates to floating platforms, and is particularly concerned with a modular design and structure for producing a floating platform for use as a pontoon, jetty or the like.

According to one aspect of the present invention, there is provided a floating platform comprising a hull and a plurality of flotation columns, wherein the hull comprises a planar deck with a depending side wall, and the flotation columns are arranged beneath the deck with their axes substantially perpendicular to the plane of the deck, the flotation columns being joined to each other by means of complementary joining formations which extend along the lengths of the respective flotation columns.

In one embodiment, the complementary joining formations are male and female linking structures.

The male linking structures may comprise a rib extending longitudinally of the column and having a transversely enlarged bead along its free edge. The female linking structure may comprise a slot formed in the wall of the flotation column, the slot leading to an undercut recesses. Most preferably, each column has a number of pairs of male and female linking structures, the male and female linking structures of each pair being arranged on diametrically opposed sides of the column. In a particular embodiment, each column has two pairs of male and female linking structures.

A second aspect of the invention provides a method for constructing a floating platform, comprising forming a hull having a deck and a side wall to form a downwardly-open box-like structure, and arranging a plurality of buoyant flotation columns within the box-structure, the axes of the columns being substantially perpendicular to the deck.

Embodiments of the invention will now be described in detail with reference to the accompanying drawings, in which: Figure 1 is a schematic perspective view of a floating platform constructed in accordance with the invention; Figure 2 is an exploded view showing the component parts of the floating platform of Figure 1;

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Figure 3 is a horizontal section through one of the flotation columns of the platform of Figure 2; and Figure 4 is a view similar to Figure 1, showing an alternative embodiment of the floating platform.

Referring out to the drawings, there is seen a floating platform 1 comprising a hull 2 of a generally rectangular form and having a flat deck 3 and a depending side wall 4. Beneath the deck 3, and supporting the hull 2, is a plurality of flotation columns 5, which in the embodiment shown are generally circular in horizontal cross-section. The columns 5 are arranged side-by-side in ranks extending across the width of the hull 2, and files extending along the length of the hull.

As can be seen from figure 3, the flotation columns are provided with male and female linking structures 6 and 7. In the embodiment shown in figure 3, the male linking structures 6 comprise ribs 8 extending longitudinally of the column and having transversely enlarged beads 9 along their free edges. The female linking structures 7 comprise slots 10 formed in the

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walls of the flotation columns, the slots leading in to undercut recesses 11. Each of the male linking structures 6 is positioned diametrically opposite to one of the female linking structures 7. The dimensions of the male and female linking structures 6 and 7 are such that, when two flotation columns 5 are placed with their axes parallel and with the bead 9 of one of the ribs B of one column aligned with one of the recesses 11 of the other column, relative movement in the axial direction of the columns to bring the columns into a side-by--side relation will cause the rib 8 to move into the slot 10 and the bead 9 to move into the recess 11. This structural interlock prevents relative movement of the columns 5 in radial directions, while allowing relative movement in the axial direction of the columns.

A rank or a file of columns may be assembled by successively interlocking a bead 9 of one column into the recess 11 of the next column. Alternatively, an array of columns 5 may be produced by interlocking columns so as to form both ranks and files. In this operation, when three columns have been assembled together to form an HLU shape in plan view, a fourth column may be added by simultaneously interlocking

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with two of the three columns, to form a 2x2 array in plan view. Further columns may be added, by interlocking them with either one or two of the columns of the existing array, as the geometry dictates.

In figure 3, the interlocking parts are shown as generally circular-section beads 9 and recesses 11.

It is to be understood that the beads 9 may be rectangular in section, or trapezoidal, or of any other shape provided that the bead 9 is of enlarged dimensions compared to the rib 8, i.e. the bead 9 is thicker than the rib 8 in the thickness direction of the rib 8. The recess 11 of the female joining portion 7 will be shaped and dimensioned so as to co-operate with the bead 9, and retain it within the recess 11. Again, the recess 11 will be wider than the slot 10 in the width direction of the slot (i.e. the circumferential direction of the column) While the flotation columns 5 are shown in the Figures as being generally circular in cross-section, it is to be understood that the flotation columns may be of any convenient shape in cross section, such as triangular, rectangular, hexagonal, or any other interlocking polygonal or curvilinear shape.

The flotation columns are advantageously formed by extrusion from a plastics material such as polyethylene, ABS, polyamide or PVC. Alternatively, the columns may be formed from fibre-reinforced resin or plastics material, or may be extruded or otherwise formed from metals such as aluminium and steel.

when the flotation columns are formed by extrusion, the male and female interlocking parts 6, 7 may be formed integrally with the flotation columns. The extruded material is then formed into lengths as required, and each length is sealed at one or both ends.

The flotation columns may include internal bulkheads 12 (shown in phantom lines in Figure 3) extending axially along the columns and dividing the interior of the column into two or more separate compartments 13, 14, so that the column remains buoyant even if the outer wall of the column is breached and water enters one of the compartments. In Figure 3, a single bulkhead extending across the diameter of the column is illustrated. Two or more diametral bulkheads, or a

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number of radial bulkheads may be provided as alternatives to the single diametral bulkhead illustrated, in order to divide the interior of the column into a plurality of axially-extending compartments. One, some or all of these compartments 13, 14 may also be filled with a closed-cell foam material to prevent the ingress of water if the outer wall of the column is breached.

The flotation columns may also be reinforced against bending by embedding reinforcing elements in the wall of the column. The reinforcing elements may be fibres or rods to resist tension, and may extend longitudinally of the column either parallel to the column axis or extending in a spiral around the wall of the column. In a particular embodiment, reinforcing elements may be wrapped round or embedded in the wall of the column along two spiral paths of opposite hand. The use of high-density foam within the columns can also contribute a resistance to bending of the columns by distributing stress from one side of the column to the other.

The hull of the platform is preferably formed from steel and/or concrete. Where the platform is intended

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to support relatively low deck loadings, a light structure can be designed and shorter flotation columns are used. If the total load to be supported by the platform is great, then longer flotation columns are selected. It is foreseen that flotation columns of up to 12 m in length may be used to provide elevated load-bearing capacity. Where the platform is intended to support point loads, then the deck must be designed with sufficient strength and stiffness to distribute the load over a number of flotation columns.

The hull may be divided into sections by transverse walls (not shown) extending below the deck 3 between the side walls 4 of the hull. Each section may accommodate an array of flotation columns, held in place by the transverse walls. In some embodiments, the flotation columns may be omitted from some of the sections.

Specifically, a gap 16 in the array of flotation columns may be provided to extend across the width of the pontoon, as is seen in the embodiment of Figure 4.

The hull may be provided on some of its side walls

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with connection elements 17, shown schematically in the Figures, to enable the hulls of two floating platforms to be connected together. In the schematic embodiment illustrated, each hull is provided with a connecting block 17 having a pair of horizontal bores 18 passing through it. The connecting blocks 17 are positioned such that, when the hulls 2 are in the desired alignment with each other, the connecting blocks of two hulls are positioned side-by-side with their bores 18 axially aligned. Connecting pins (not shown) may then be passed through the bores and secured, to provide a rigid connection between the hulls 2 of the floating platforms. It is foreseen that platforms may be joined end-to-end to form an elongated platform for use as a floating road or bridge, or platforms may be joined in-to-end and side-to-site to form a two-dimensional array with an extensive deck area. Rectangular platforms may also be joined together in a two-dimensional array, with one or more platforms omitted from the central region of the array to form a "Moon pool".

The platform illustrated in a 4 is particularly suitable for joining in end-to-end relationship to form a floating roadway or bridge. Where each

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platform has a transverse region from which flotation columns are omitted, this provides clear transverse passageways 16 beneath the hulls of the platforms so that a proportion of the energy of waves impinging on the sides of the platform can pass through these passageways, reducing transverse wave and current loading on the floating roadway. If all the more traffic is required to pass through the bridge, one or more platforms at the central region of the bridge may be provided with releasable connecting elements 17 so that an opening may be temporarily formed in the bridge by swinging one or more sections out of the line of the bridge, to allow waterborne traffic to pass through. The sections may be swung back into line and reconnected to restore the bridge after the waterborne traffic has passed through.

To assemble a floating platform 1 of the present invention, the hull 2 is first fabricated with a deck 3 of the dimensions required, and side walls 4 and transverse walls are then attached to the deck to provide a downwardly-open box-like structure with its interior subdivided into the required number and shape of sections by the transverse walls. Each section which is to be provided with flotation columns may be

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further formed with securing elements to receive one end of each of the flotation columns, to fix them in position relative to the hull. Connection elements are then provided as required on the external side walls of each hull.

The hulls may be fabricated on site, or may be produced at a central location and transported by road or rail to the site where the platform is to be deployed.

The flotation columns are preferably produced by extrusion, and are then cut to the required length and sealed. It will be understood that only one end of the flotation column needs to be sealed, in order for the column to displace water and provide buoyancy to the platform. Preferably both ends of each flotation column are sealed. The flotation columns may also be produced at a location remote from the point of use of the platform, and may be transported to the deployment point either singly, or in partially preassembled units. The single flotation columns, or the partially preassembled units, may then be assembled on-site by joining the columns together using the axially-extending the male and female joining components 6 and

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7 described above.

Most preferably, the flotation columns circular-section cylinders of a diameter of less than 1 m, and most preferably between 20 and 30 cm. The flotation columns 5 may have a wall thickness of up to 10 mm, when produced from plastics materials Flotation columns formed from plastics material and having such dimensions are easily handled by manual labour, so that the platform requires the minimum of machinery for its final assembly.

At the point of assembly, the flotation columns 5 are introduced into the downwardly-open sections of the hull 2 and are secured to the hull and to each other.

The assembled platform is then launched, preferably using a crane to lift the platform into the water, with the flotation columns 5 extending vertically through the water surface to support the hull 2. The hull is preferably clear of the water, to reduce any corrosive effect of immersion in water. It will be appreciated that, in the embodiments shown, the flotation columns 5 are positioned side-by-side and in contact only along the axial regions where the male

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and female joining formations 6 and 7 extend. Water can thus penetrate between the columns 5, so that each column experiences balanced horizontal hydrostatic forces. The outermost flotation columns in the array thus do not experience large horizontal forces directed toward the centre of the array, as would be the case it water was not permitted to enter between the flotation columns.

Once launched, each floating platform 1 may either moored in place at its required location, or may be connected to another floating platform using the connection elements 17. To connect two floating platforms together, they are brought into the required side-by-side or end-to-end relationship, and connecting pins are passed through the aligned bores 18 of their respective connecting blocks 17. It is foreseen that the spacing of the connecting blocks on each pair of opposite sides of the platform will be such that platforms may be connected together not only in side-by-side and end-to-end relation, but also so that an end of one platform may be connected to a side of another.

While the connecting elements shown in the Figures use

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a pair of spaced bores 18 and connecting pins to provide a substantially rigid joint between adjacent hulls, it is foreseen that a jointing arrangement providing for relative rotation of adjacent platforms about a horizontal axis may be provided, in order to permit a floating platform made of many modules to flex under the action of a swell. For example, when a number of platforms such as shown in Figure 4 is joined in end-to-end relation to form a bridge structure, a single jointing pin may be used in one of the bores 18 of each block 17 to enable adjacent platforms to flex relative to one another about the horizontal axis of the pins. Other forms of connection between platforms may be provided, such as connection by means of cables or chains. When the hulls are connected together, bridge pieces (not shown) may be inserted to provide a continuous deck surface across the joint between adjacent platforms.

As mentioned above, although the platforms described herein are generally rectangular in plan form, platforms of other polygonal shape in plan may be provided, and platforms having a polygonal, curved or curvilinear outline in plan may also be fabricated.

When producing such platforms, the interior of the

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hull will be subdivided into sections by transverse walls, the shape of the sections corresponding to these selected shape of the flotation columns, to provide location for the flotation columns.

The platforms can be used f or building wharves, bridges, or as supports for buildings, especially in water which is of a depth such as to make piling and economic, or in water in which the tidal range must be taken into account. An advantage of this platform is that by using primary materials such as plastics, which are very cheap and light and do not harm the environment, a platform may be produced to which is economical, safe and ecologically sound.

The modular nature of the platform provides a very flexible structure that can be changed easily and repaired very conveniently.

One of the main differences from the designs that already have been built so far is that the flotation columns 5 collectively provide a buoyant body which is divided into a large number of cells, so as to decrease the hydro-static forces on each flotation column in the water.

The preferred cross sectional shape for the flotation columns it is a circle, because when the circles are connected together water may pass between the columns, consequently it decreases the hydro static force on the couplings, as the columns are connected together individually.

The capacity of loading can be increased by increasing the length of the flotation columns.

The platform does not lose stability even if some of the flotation columns are breached, because the floating part has been built with a multiplicity of flotation columns. In order to provide such a margin of safety, the platform has in some percentage pay redundancy or "over design" as regards the number of flotation columns provided for the predicted load.

Claims

Claims: 1. A floating platform comprising a hull and a plurality of flotation columns, wherein: the hull comprises a planar deck with depending side walls; and the flotation columns are arranged beneath the deck with their axes substantially perpendicular to the plane of the deck, the flotation columns being joined to each other by means of complementary formations which extend along the lengths of the respective flotation columns.
2. A floating platform according to claim 1, wherein the complementary formations are male and female linking structures.
3. A floating platform according to claim 2, wherein the male linking structures each comprise a rib extending longitudinally of the column and having a transversely enlarged bead along its free edge, and the female linking structures each comprises a slot formed in the wall of the flotation column, the slot leading to an undercut recess adapted to accommodate the bead of a male linking structure.S
4. A floating platform according to claim 2 or claim 3, wherein each column has a number of pairs of male and female linking structures, the male and female linking structures of each pair being arranged on diametrically opposed sides of the column.
5. A floating platform according to any preceding claim, wherein transverse walls extend between the side walls and beneath the deck, to divide the hull into a number of sections, and wherein flotation columns are provided in at least one of the sections.
6. A floating platform according to any preceding claim, in which the flotation columns are sealed at their upper ends and open at their lower ends.
7. A floating platform according to any of claims 1 to 5, in which the flotation columns are sealed at their lower ends and open at their upper ends.
8. A floating platform according to any of claims 1 to 5, in which the flotation columns are sealed at both their lower ends and their upper ends.S
9. A floating platform according to any preceding claim, wherein the flotation columns are generally circular in transverse section.
10. A floating platform according to any of claims 1 to 8, wherein the flotation columns are generally polygonal or curvilinear in transverse section.
11. A floating platform according to any preceding claim, wherein the flotation columns are internally divided into a plurality of separate compartments by a number of axially-extending bulkheads.
12. A floating platform according to any preceding claim, wherein the deck is rectangular in outline.
13. A floating platform according to any of claims 1 to 11, wherein the deck is polygonal or curvilinear in outline.
14. A method for constructing a floating platform, comprising the steps of: providing a hull having a deck and a side wall to form a downwardly-open box-like structure; arranging a plurality of buoyant flotationS-columns within the box-structure, the axes of the columns being substantially perpendicular to the deck; and joining adjacent pairs of columns together by means of complementary joining structures extending axially of the respective columns.