PROCESS FOR THE PRODUCTION OF A HYDRAULIC ENGINEERING STRUCTURE, SUCH AS A PIER, JETTY AND THE LIKE

Abstract: The invention relates to a process and a floating apparatus (1, 2, 18) for the construction of columnlike elements (16, 17), forming part of a pier, a jetty or the like marine structure, in which a first part (16) is manufactured on a support (5) attached to the floating apparatus. whilst said apparatus rests on the waterbottom (15), which first part (16) is lowered on the waterbottom (15) after lifting the floating apparatus to free it from the waterbottom and after displacement to a place with deeper water. There the next part (17) is made upon the still deeper water, lowered again until they rest on the bottom, after which the next part is made and so on until the final height and destination are reached. The floating apparatus is completely equiped (10, 11, 14) for performing the work and has a construction such, that it can be disengaged from the finished structure.

Description: The invention relates to a process for the production of a marine engineering structure, such as a pier, a jetty, a reservoir, etc., on a water bed by placing on the water bed a hollow column whose base part is broader than the part running up from it, said column being placed on the water bed from an apparatus having buoyancy comprising a platform entirely designed as a workshop and provided with means which permit placing of the said platform on the water bed, a first part, such as the base part, of the said column being manufactured by means of said platform with the aid of a temporary support in such a way that the column can extend through an opening or recess of the platform, but also in such a way that the platform can be moved away from the ready column, all this taking place in such a way that the top part of the already finished part of the column remains accessible from the deck of the platform. A process of this kind is known from GB-A-956,386. According to said known process a column is made at the side of its final destination by first of all placing a lift island at said location, which lift island comprises a pontoon and a number of columns along which the island can be lifted out of the water by means of hydraulic lifting devices. In the position in which the pontoon or platform of said lift island is high above the water level a prefabricated base element or caisson is moved between the legs of the lift island by means of a barge, is subsequently suspended from the lift island and thereafter lifted from the barge by moving the lift island further upwardly after which the barge can be removed. Thereafter the base is lowered and upon said base a further part of the column is manufactured by using concrete which manufacturing takes place from the work platform of the lift island. After having manufactured a first part on said base the so far completed column is lowered on the water bed and allowed to penetrate into it, whereas manufacturing of the column upwardly continues until the column extends through an opening or recess of said work platform. After completion of the column the lift island is removed either by placing it on addition pontoons to obtain a height sufficient to float over the top of the manufactured column, or by providing the platform with a recess open at one side. Said known method is expensive because it does not require a simple floating device or pontoon but requires a lift island with a jackup mechanism. Purpose of the invention is to provide a method which is more simple and less expensive. According to the invention this purpose is achieved in that the first part of the column is made whilst the platform rests through its bottom side or through supporting legs upon the water bed in shallow water and is made with said temporary support at or in the said opening or recess, that after manufacturing the said first part of the column the platform, provided with adjustable buoyancy, is moved together with said already finished part of the column to deeper water and the already finished part of the column is placed on the water bed either directly or with the interposition of a temporary support having adjustable buoyancy, a further part of the column is subsequently manufactured and, unless this is the last part, the platform is moved again to yet deeper water and the column is lowered further, the already completed part of the column always being first lifted through regulation of the buoyancy of the platform and lowered after shifting, and, the column being double walled, on completion of the column, the hollow double wall of which may or not be already provided with a concrete filling with concrete, which column is lifted again by means of the platform and taken to its destination where it is finally lowered and fixed. The invention is therefore based on the principle that one begins by making the column on a platform with adjustable buoyancy designed as a pontoon, which is placed on the water bed either by setting this pontoon on the bank at high water or near the bank, lowering it onto the water bed by reducing buoyancy, with or without the use of telescopic supporting legs which are known per se. Once a first part is made, using the advantage that it is still possible to have supplies from the bank, the pontoon is moved to slightly deeper water, and the already completed part of the column is placed on the water bottom. The next part of the column is then built on the already completed part, the column part then obtained is lifted by connecting it to the pontoon and slightly increasing the buoyancy thereof, and one then travels to the next point where the column can be lowered again, in order to produce the then, for example, remaining part. When the column has been produced in this way, it is standing on a place on the water bed which is not the correct one. The column can then be provided with a concrete filling depending on whether this is desirable. When the pontoon with the partially completed column has moved away from the bank, the advantage obtained during further construction on the column is that the part already standing on the water bottom forms an anchor point, despite the fact that further construction work is being carried out on it. When the column is complete and the pontoon is lowered slightly, the latter is connected again to the column, and this column is lifted by increasing the buoyancy and then travelling to the destination, where the final positioning and anchoring can take place also from the pontoon, which still encloses the column with its opening or recess. The pontoon cannot move away until this work has been completed and the opening or recess has been opened. During the production of the column in particular during the production of the base part, the opening or recess can be closed off by a removable cover, by supporting bars and the like which serve as temporary support. If this part is to be lowered via the recess or opening, a working crane preferably designed as a bridge crane is used, the column part is lifted with it and is then lowered after the covering is removed from the opening or recess. According to a preferred embodiment of the invention, the means for supporting the first part of the column during its manufacturing and during lowering of said manufactured first part consists of a body with adjustable buoyancy which body fills up the opening or recess respectively. This body, which can be detachably coupled to the two pontoons, or to one pontoon, then has a top deck which will be flush or virtually flush with the deck of the pontoon(s). After production of the base part of the column, this body is lowered to below the pontoon, the finished column part is separated e.g. by means of the hoisting means from the body which is removed, and then the column part can be lowered further until it rests on the water bottom, which lowering may be controlled by its buoyancy. It is, however, also possible to proceed in such a way that the ready column part is lowered with this body and is made to rest with it on the water bottom. After completion of the next column part, it is lifted by means of the pontoon from the body resting on the water bottom and travels to another place where the finished column part is lowered onto the water bottom. The body is then given more floating power, so that it is removed and can be reused. It is conceivable to leave this body under the column until the latter is completed. It is essential that the height of the column should always be increased in stages, while the column always rests on the water bottom and can always be filled with concrete and then through its weight forms an anchoring place for the floating pontoon(s) being used as a workshop. It is observed that from International Patent Application WO 87/03026 laid open for inspection a double-walled hollow column with a sharp bottom edge and a broad base is known which can be brought into a more or less deep floating condition and can be lowered upon the water bed by pouring concrete in the hollow wall. The invention will now be explained in greater detail with reference to the drawings. Figure 1 shows in top view an embodiment of the device for using the process according to the invention. Figure 2 is a cross section along the line II-II of figure 1 and shows the device of figure 1 also in schematic form. Figure 3 is also a schematic cross section along the line III-III of figure 1. Figure 4 serves to explain the process. Figure 5 shows a schematic top view of another embodiment of the device. Figure 6 shows schematically a side view of the device of figure 5. Figure 7 shows the device of figures 5 and 6 in another position to explain the process according to the invention. The device shown in figure 1 comprises a pontoon having parts 1 and 2 which are attached to each other along the line 3 by means of detachable fastening means which are not shown. When connected to each other, these pontoon parts 1 and 2 enclose a recess 4 which is partly in pontoon 1 and partly in pontoon 2. When these two parts 1 and 2 are separated, the recess is open. This recess contains a third body 5 with buoyancy, the top face 6 of which is essentially flush with the deck 7 of the two pontoons 1 and 2. This deck has a rail track 8, 9 for a bridge or portal crane 10, which is shown only schematically, and which is provided with a travelling trolley 11 with hoisting means 12. The deck contains all other facilities which are necessary, indicated by the rectangle 13 and the schematically shown concrete mixer 14. At the start of production of a column the pontoon 1, 2, 5 is placed on the water bed 15, either directly or with supporting legs, as schematically indicated in figure 6. A first part 16 of the column to be produced is then produced or placed on the body 5. Through increasing the floating power or using the tide, the platform is then floated and travels to another place, as schematically shown in figure 4. The floating power of the part 5 is reduced there, so that the latter sinks and comes to rest, for example, on the bed 15′, but in such a way that the top side of the already produced column part 16 is approximately at the level of the deck 7, so that the next column part 17 can be produced or placed on top of this part. After that there are various possibilities. The part 5 can be removed and the column can be placed on the bed 15′ by means of the crane. It is also possible to move to a slightly deeper level and lower the column further then so that the next part can be placed on top of it. After completion of the column and generally after filling of the hollow wall with concrete, the column is lifted by first of all taking the pontoons to a lower floating level, then connecting them to the column and after that lifting it using the buoyancy of the pontoons. The column is then taken to its destination and lowered, either with the aid of the crane or in combination with the crane, by reducing the buoyancy. When the column is on the water bottom, it must penetrate deeply enough into it, and this work can also be carried out from the platform via the inside of the column, i.e. via the opening which is inside the inner wall of the hollow wall. When the column is finally positioned, the pontoon parts 1 and 2 are separated from each other and they are moved away, following which the pontoons are taken back to the bank for the production of the next column. If a series of columns has to be positioned, they can be placed at the correct distance from each other using a hinged parallelogram, as described in the earlier mentioned international patent application, which has been laid open for inspection. This frame can be connected to the existing column from the pontoon. This frame can also be coupled beforehand to the column already in position and given buoyancy at the free end, so that this frame can be connected to the new column as soon as the latter is brought in with the platform. In the embodiment according to figures 5 to 7 there is a single pontoon 18, which on one side edge has a recess 19 containing a body with adjustable buoyancy. The deck of the pontoon has the same installations as those indicated for the embodiment of figures 1 to 4, of which only the rail tracks 8 and 9 are shown. The embodiment of figures 5 to 7 is provided with telescopic legs 21 near the corners of the pontoon. With these legs the pontoon can be displaced horizontally on a sloping or uneven surface near the bank. The body 20 is again used to produce the first column part 16 on it, said part subsequently, as shown in figure 7, being lowered by means of the body 20 onto the water bed 15′, following which a second part can be placed or produced on the first part of the column in the same way as described for the embodiment of figures 1 to 4. When the column is completed, it can be floated to its destination with the aid of the pontoon 18. When the positioning is completed, the pontoon can move away immediately, since the recess 19 is open.

Claims: Process for the production of a marine engineering structure (16, 17), such as a pier, a jetty, a reservoir, etc., on a water bed (15, 15′) by placing on the water bed (15, 15′) a hollow column (16, 17) whose base part (16) is broader than the part (17) running up from it, said column (16, 17) being placed on the water bed (15, 15′) from an apparatus (1, 2, 18) having buoyancy comprising a platform (1, 2, 18) entirely designed as a workshop and provided with means (21) which permit placing of the said platform (1, 2, 18) on the water bed (15, 15′), a first part, such as the base part (16), of the said column (16, 17) being manufactured by means of said platform (1, 2, 18) with the aid of a temporary support (5, 20) in such a way that the column can extend through an opening (4) or recess (19) of the platform, but also in such a way that the platform can be moved away from the ready column, all this taking place in such a way that the top part of the already finished part of the column (16, 17) remains accessible from the deck (7) of the platform, characterized in that the first part (16) of the column (16, 17) is made whilst the platform (1, 2, 18) rests through its bottom side or through supporting legs upon the water bed (15, 15′) in shallow water and is made with said temporary support at or in the said opening (4) or recess (19), that after manufacturing the said first part (16) of the column (16, 17) the platform (1, 2, 18), provided with adjustable buoyancy, is moved together with said already finished part (16) of the column to deeper water and the already finished part of the column is placed on the water bed (15′) either directly or with the interposition of a temporary support (5, 20) having adjustable buoyancy, a further part (17) of the column is subsequently manufactured and, unless this is the last part, the platform (1, 2, 18) is moved again to yet deeper water and the column is lowered further, the already completed part (16, 17) of the column always being first lifted through regulation of the buoyancy of the platform (1, 2, 18) and lowered after shifting, and, the column (16, 17) being double walled, on completion of the column, the hollow double wall of which may or not be already provided with a concrete filling which column (16, 17) is lifted again by means of the platform (1, 2, 18) and taken to its destination where it is finally lowered and fixed.

Inventors: MASSOUDI, AHMAD PASDARAN GOLESTAN 5
Applicants: DARYA PAYE JETTY CO., LTD.
Application year: 1989
Main classification: E02D23
IPC codes: E02B17, E02B3, E02D23