DK177941B1 - Buoyant breakwater - Google Patents

Abstract

Buoyant breakwater for dissipating energy from waves, wherein the breakwater comprises two or more upper buoyant tubular members and at least one lower non-buoyant tubular member, where said tubular mermbers are arrranged in bulkheads, said bulkheads being arranged in spaced relationship along the longitudinal direction of the tubular members, substantially perpendicular to said longitudinal direction of the tubular members.

Description

Buoyant breakwater

Field of the Invention

The present invention relates to a buoyant breakwater for dissipating energy from waves.

Background of the Invention

The sea's action on the coastline has been going on for millennia helping to shape the coastline as we more or less know it. However, due to increased population and especially population along the coastlines it is increasingly interesting to be able to conserve the coastline in its present form and shape such that infrastructure, housing etc. is not harmed by the naturally occurring interaction between the sea and the coast line.

An example of an arrangement to retard the flow of tidal water is disclosed in GB 2204080. The arrangement comprises an upper buoyant section comprising two buoyant tube-formed members arranged in a relatively stiff frame. This upper buoyant section is designed to float on the surface of the body of water. A non-buoyant lower section is coupled to the upper buoyant section by a flexible net section. The non-buoyant section is designed to be anchored close to the bottom, and facilitate the suspension of the net, substantially vertically in the body of water between the upper buoyant section and the lower non-buoyant section. In this less the upper section will be able to, due to the flexible character of the net, follow and move with the surface of the water, i.e. Let waves and swells roll under the upper section. Accordingly although the suspended net obstacles or limits water flow due to tidal changes, the arrangement does not have any impact on the wave patterns and other surface occurrences.

Therefore, a number of different ways to hinder the sea's impact on the coastline have been suggested and implemented over the years. Along some coast lines, heavy concrete structures are built into the sea in order to make the drifting sand's sediment along the coast and in this less preserve or even increase the extent of the coast line and in this less protect buildings and infrastructure further away from the coast . In conjunction with other infrastructure constructions such as harbors and the like, breakwaters are used in order to protect the harbor and the boats / ships in the harbor. Usually these are also made as heavy concrete constructions, sheet piles etc.

Common to all these constructions is that they are very heavy and expensive to install, and furthermore for areas with less exposure to severe ocean forces the traditional methods of providing protection against the forces of the sea appear to be more than sufficient and therefore increasingly expensive with respect for the purpose and task at hand.

Object of the Invention

It is therefore an object of the present invention to provide a breakwater which will dissipate the energy from the waves and at the same time be relatively cheap and easy to install and manufacture.

Description of the Invention

The present invention consistently provides a buoyant breakwater for dissipating energy from waves, the breakwater comprising two or more upper buoyant tubular members and at least one lower non-buoyant tubular member, where said tubular members are arranged in bulkheads, said bulkheads are arranged in spaced relationship along the longitudinal direction of the tubular members, substantially perpendicular to said longitudinal direction of the tubular members.

In the context of the present invention at least the term dissipate shall be construed as meaning absorbent hole or partial, such that as a wave encounters the inventive buoyant breakwater of the invention, the kinetic energy of the wave is fully or at least partially transferred to the buoyant breakwater, such that the water behind the breakwater in the waves direction of travel will be calm, or at least much calmer than on the other side of the breakwater.

The less in which the energy will be dissipated by the breakwater is discussed below.

The arrangement of the tubular members such that there will always be at least two upper buoyant tubular members and at least one lower, non-buoyant tubular member ensures that the breakwater will float more or less on the surface of the water into which it is placed. and at the same time due to the provision of the triangular relationship will absorb the energy from the waves in a substantially rolling motion in that the wave will lift the first buoyant tubular member and at the same time try to force the second buoyant tubular member into the water surface and lift the non-buoyant member. This action will altogether require a substantial amount of energy which energy will be taken from the wave action and thereby the buoyant breakwater with this arrangement will dissipate the energy from the waves. If the tubular members are foreseen to be rather long the rolling movement will be a flexible movement along the tubular members and as such a substantial amount of energy will be obtained / absorbed in the buoyant breakwater. The breakwater will also cause some waves to break over the breakwater. This will transfer the energy of the wave to the breakwater, by the breakwater causing the wave to "disintegrate" and produce the white foam (air bubbles mixed with water), which very effectively dissipates the energy of the wave.

Furthermore, by adjusting the weight of the non-buoyant member it is possible to position the buoyant members relative to the surface of the water in the most opportune manner. Depending on the position and the typical weight pattern in a given position it may be advantageous to allow the buoyant members to ride very low on the surface whereas in other situations it may be advantageous that the buoyant members are substantially as high on the water as possible. This can easily be achieved by adjusting the buoyan-cy / weight of the non-buoyant member.

In a further advantageous embodiment of the invention the tubular members are polymer-based pipes or steel pipes. Especially by using polymer-based pipes the flexibility of the breakwater as such is very high and a large degree of twisting will be absorbed in the breakwater due to the flexibility of the polymer-based pipes. The same is naturally true for steel pipes, however, steel pipes tend to be more stiff and will therefore require longer length before exhibiting the same properties.

The bulkheads provided in spaced relationship along the longitudinal direction of the tubular members serve to maintain the three or more tubular members in their proper position. When the bulkheads are placed relatively close to each other, a relatively stiff breakwater will be created whereby more flexible pipes will be able to absorb more energy. By spacing the bulkheads with relatively large intervals the breakwater will be more flexible and be able to absorb energy from even small waves.

In a further advantageous embodiment, the bulkheads are each provided with apertures corresponding to the cross-section of the tubular members. When manufacturing the buoyant breakwater as described with reference to claim 7 it is possible to arrange the bulkheads at predetermined intervals such that the apertures are in line and then insert the tubes through a plurality of bulkheads thereby creating a relatively long breakwater in a very simple manufacturing process.

In order to adjust the buoyancy of the non-buoyant tubular member the lower non-buoyant tubular member is filled with a granular material heavier than water, such as for example sand, gravel, rocks or filled with concrete. By using sand, gravel or rocks these materials may be obtained in the position where the breakwater is to be installed and as such the cost of transportation of the heavy materials may be substantially lower. Naturally, when the non-buoyant tubular member is filled with concrete, a certain amount of transportation is necessary, although it will be possible to use local materials on site in order to fill the non-buoyant member on site.

In a still further advantageous embodiment the means for attaching said breakwater to an anchor construction is provided in one or more of the bulkheads. By attaching the bulkheads the tubular members remain more or less uninterrupted and untouched, and therefore the tubular's strength also with respect to twisting is maintained as much as possible which is a very important long-term aspect of the present invention.

In a further advantageous embodiment, a plurality of bulkheads are provided with a fastening beam, and where a deck is fastened on top of said fastening beam, said deck voltage at least between two adjacent bulkheads. By providing a deck fastened on top of the bulkheads the breakwater may also serve as a pier or mooring pier for ex ample in marinas and the like, and as such a double purpose is obtained with the buoyant breakwater according to the present invention.

As already mentioned above, the invention also discloses a novel and inventive method for manufacturing the buoyant breakwater as described above where a plurality of bulkheads are arranged with a pre-determined distance between adjacent bulkheads, and aligned perpendicular to a substantially linear axis; the tubular members are arranged with their longitudinal direction substantially parallel to the linear axis, and fixed in or on the bulkheads, such that at least two tubular members are arranged above at least one lower tubular member, and where the lower tubular member is made non -buoyant.

Further embodiments of the method are also disclosed which all serve to obtain the objects and advantages described above with reference to the various advantageous embodiments of the invention.

Description of the Drawing

The invention will now be explained with reference to the accompanying drawing, wherein

Figure 1 illustrates a breakwater construction according to the invention

Figure 2 illustrates a bulkhead used in the breakwater

Figures 3 and 4 illustrate various methods of anchoring the breakwater.

Detailed Description of the Invention

Figure 1 illustrates a perspective view of a section of a buoyant breakwater according to the present invention. The breakwater 10 in this embodiment comprises three tubular members 1, 2, 2 'which are held by a number of bulkheads 3 in order to fix the tubular members 1, 2, 2' relative to each other. Two of the tubular members 2, 2 'have buoyancy such that they will float on or in the water whereas the third tubular member 1 is non-buoyant and therefore will not float on water.

It should be noted that breakwaters according to the invention may comprise any number of tubular members connected by bulkheads, but for illustrative purposes this description will focus on the above mentioned construction.

In the assembly illustrated, the tubular member 1 will provide stability to the triangular construction such that the two tubular buoyant tubular members 2 will float on or in the surface of a water expand whereas the non-buoyant tubular member 1 will be submerged. In this less stable construction is achieved, but due to the floating capabilities of the breakwater 10 any waves hitting the breakwater 10 will have its energy dissipated by twisting and rolling movement of the breakwater. If a wave hits the breakwater from right to left in the figure, the right tubular member 2 will be elevated relative to the left tubular member 2 '.

Due to the buoyancy of the left side tubular member 2 'a substantial amount of energy is needed in order to submerge the buoyant tubular member 2' into the water. At the same time, the non-buoyant member 1 will be elevated, and due to its weight it will create a certain resistance and thereby also require a substantial amount of energy in order to allow the non-buoyant member to be elevated.

Due to the construction of the breakwater and especially the spacing of the bulkheads 3 it is possible for the breakwater to twist such that adjacent bulkheads may come out of alignment due to the flexibility of the tubular members 2, 2 ', 1. This flexibility also requires input of energy which is derived from the waves whereby together with the mechanism already explained above the wave energy is more or less completely dissipated into the buoyant breakwater according to the present invention.

Figure 2 illustrates a plain view of a bulkhead 3, where a number of apertures 4 are provided. The apertures have a size such that they will snugly accommodate the tubular members 1, 2, 2 '. In a preferred embodiment of the invention mentioned earlier the tubular members as well as the bulkheads are made of a polymer-based material, for example plastic with reinforcement, such that it is possible to weld the tubular members to the bulk heads and in this Less create exceptionally strong connections and an over-all stable construction with a large degree of integrity. The top edge 5 of the bulkheads may be provided with a beam 6 such that a deck or boardwalk may be attached to the breakwater 10. In this less the breakwater may serve the dual purpose of also acting a mooring, especially in calmer waters where the movements of the breakwater will be less than for example in open seas.

In order to keep the breakwater in place the breakwater should be anchored or fastened at intervals. Figure 3 illustrates one embodiment where an anchor block 7 is placed on the sea bottom or ocean bottom and by means of chains 8 is connected to lower portions of the bulkheads 3. In this manner the anchor block 7 will retain the breakwater in position and still allow the breakwater to twist and move in order to dissipate energy from the waves as already described above.

Turning to Figure 4 a further means of anchoring the construction is illustrated. In this embodiment, a number of piles 9 are hammered into the sea bottom. On the bulkheads 3, fastening rings 11 are provided, such that the breakwater 10 may slide up and down (as indicated by the double arrow), as the surface of the water rises or falls.

Claims (10)

A liquid wave switch (10) for dissipating energy from waves, wherein the wave switch (10) comprises two or more upper liquid tubular members (2, 2 ') and at least one lower non-liquid tubular member (1) and bulkhead (3). spaced apart in the longitudinal direction of the tubular portions (1, 2, 2 ') and substantially perpendicular to the longitudinal direction of the tubular portions, characterized in that at least two upper liquid tubular portions (2, 2') and at least one lower nonlinear portion are provided. liquid tubular portion (1) all arranged in bulkhead (3). The liquid waveguide of claim 1, wherein the tubular members (1, 2, 2 ') are polymer-based tubes or steel tubes. The floating breakwater of claim 1 or 2, wherein each bulkhead (3) is provided with apertures (4) corresponding to the cross-section of the tubular portions (1, 2, 2 '). A liquid wave breaker according to claim 1 or 2, wherein the lower tubular member (1) is filled with a granular material heavier than water, such as e.g. sand, gravel, stone, or is filled with concrete. A floating breakwater according to any one of claims 1 to 3, wherein means (8) for securing the breakwater to an anchor structure (7) are provided in one or more of the bulkheads. A floating breakwater according to claim 1, wherein a plurality of bulkheads (3) are provided with a fastening beam (6) and a tire (5) is fixed on top of the fastening beam (6), which comprises at least two adjacent shot (3). A method of producing a floating breakwater (10) according to any one of claims 1 to 5, wherein - a plurality of bulkheads (3) are arranged at a predetermined distance between adjacent bulkheads (3) and created perpendicular to a substantially linear axis, - the tubular parts (1, 2, 2 ') are arranged with their longitudinal direction substantially parallel to the linear axis and fixed in or on the bulkheads (3), characterized in that the arrangement is such that at least two tubular parts (2, 2 ') is arranged over at least one lower tubular portion (1) and the lower tubular portion (1) is rendered non-liquid. The method of claim 7, wherein the tubular portions (1, 2, 2 ') and the bulkheads (3) are polymer-based and wherein the tubular portions (1, 2, 2') are tubes having a substantially constant circular cross-section, and in which the bulkheads (3) are provided with openings (4) corresponding to the number of tubular parts (1, 2, 2 ') which are built into the corrugated switch (10) and wherein the tubular parts (1, 2, 2') ) is passed through the openings (4) in consecutive bulkheads (3) and welded to the bulkheads (3). The method of claim 7 or 8, wherein means are provided in the lower tubular portion (1) for introducing material heavier than water and optionally water. A method according to any one of claims 7-9, wherein the wave breaker (10) is provided with a tire (5) either before or after installation in the water, which tire (5) is fastened to fastening elements provided on the bulkheads (3).