EP2188455A1

EP2188455A1 - Method and installation for erecting concrete structures in seawater

Info

Publication number: EP2188455A1
Application number: EP08803611A
Authority: EP
Inventors: Jens JÄHNIG
Original assignee: Jahnig Felssicherung und Zaunbau GmbH
Current assignee: Gicon Windpower IP GmbH
Priority date: 2007-09-11
Filing date: 2008-09-03
Publication date: 2010-05-26
Also published as: DE102007043269A1; WO2009033994A1; DE102007043269B4

Abstract

The invention relates to a method for erecting concrete structures, said concrete structures being in contact with salt water at a later point in time or being erected in salt water. According to the invention, aggregates are used that have the same salt content as the seawater. Seawater is used as the mixing water. The invention allows the ship-based erection of durable concrete structures at sea with only little need for transportation.

Description

Process and installation for the construction of concrete structures in seawater

The present invention relates to a method and a plant for the construction of concrete structures in seawater, preferably in greater coastal distance.

Buildings to be built on or in the sea, for example, foundations for wind turbines transmission towers, radio towers, measuring towers, guide posts for driving channels or anchorages of buoys, tons, beacons and the like. For the construction of the concrete is currently produced on land or at least its components (binder, aggregate and Anmachwas ^¬ ser) provided on land. For large structures, the provision and transportation costs are a significant cost factor. This is especially true for the foundations of offshore wind turbines. If these are to work economically, their construction costs must be low. Offshore wind turbines can be fully pre-produced in the port and then towed to their locations where they need to be anchored. As foundations floating foundations have been proposed, which include a plurality of anchoring elements positioned on the seabed as ballast body and hold the wind turbine at the specified location. The anchoring elements resting on the seabed for positioning are made of concrete with a volume of up to 1,000 m ³ each or more. In the dimensions mentioned, the use of land-based or anchoring structures on land is associated with high costs and high costs in terms of transport.

At present, work vessels are used for the construction of concrete structures at sea, which have a mixing and delivery unit to mix an underwater concrete as a standard concrete at the site and pump to the seabed. All required for the concrete recipe raw materials (cement, sand, gravel, water, additives) are from their Herstellungsbzw. The place of extraction was taken to a port, loaded there in silos on the working ship and taken from there to the place of work. Because of the limited loading capacity of the working ships, they must return to the port more frequently than would be required, for example, to replace the personnel.

Based on this, it is an object of the invention to provide a method and a system that allow a more economical concreting work in the sea. In particular, the associated transport costs should be reduced and the technological activity cycles should be extended.

Another object of the present invention is to provide such a method and apparatus for use at a greater distance from the shore, which requires the least possible frequency of ship movements.

With the method according to the invention can be in contact with seawater, in particular standing in sea concrete structures even at a greater distance from the coast, for example, a ship-borne concrete mixing and conveyor system, ie ultimately with a special ship. The total weight of the structures erected by the ship in one action may be substantially greater than the carrying capacity of the ship. In addition, the total weight of the concrete structures can be significantly greater than the weight of land-borne material. The invention makes it possible by exclusively or at least predominantly aggregates and mixing water are used for the production of the concrete from which the structure is built, which are taken from the sea. The aggregate is sea gravel from the seabed. The mixing water is seawater. Here, the terms "seawater" and "seawater" are used synonymously for saline water, which is not freshwater.

The ship carries at least one ash-generated binder component in suitable bunkers. The remaining constituents of the concrete, in particular its aggregate and its mixing water, originate from the sea and are correspondingly saline. It has been found that with saline giants, which have been obtained in the sea and according to saline mixing water can produce a durable and durable concrete. This is particularly the case when the aggregate extracted comes from a deposit from whose vicinity suitable seawater has been taken, which has the same salt content as the seawater with which the aggregate was previously in long-term contact.

Furthermore, it has been found that cement and fly ash, in particular hard coal fly ash, are suitable as the binder component. Preferably, a binder of cement, fly ash and additives can be used here. In the method according to the invention, a large part, for example about 50% of the total transport capacity of the production ship in question can be used to transport the binder component and optionally the metal structures or scaffolds to be installed in the concrete structure. This results in long cycles for the use of the production ship. The number of harbor voyages depends on the loading capacity of the binder.

The production ship preferably contains at least in a preferred embodiment a plurality of silo containers, in which seaweed obtained from the seabed can be temporarily stored. The intermediate storage can serve several purposes. For example, it may allow drainage of the sea gravel to adjust a desired degree of moisture. Such silo containers can be regularly refilled with sea gravel, which is obtained, for example, by a suction dredger in the rinsing process, transported to the production vessel and then conveyed into the aggregate bunker. This method is particularly suitable for production in larger coastal distance, which also results in cost savings, because the port only for the binder uptake, i. less often must be approached.

Furthermore, the production vessel can also load its bunkers with sands and gullies from silo facilities in the port to begin production before the suction dredger delivers sand and gravel from the seabed.

The production ship preferably has a concrete conveyor system in addition to the mixing device. The concrete delivery system consists of storage tanks as an intermediate station from the transition of the discontinuous production of fresh concrete and the continuous pumping by stationary concrete pumps in the required number (usually two or three) and designed according to the building specific installation conditions piping including the interposed depending on the requirement boom. The concrete installation on the seabed is carried out in the process of underwater concrete. It can be installed while monitoring and monitoring equipment for concrete installation.

In the construction of anchoring elements for anchoring floating foundations, in particular wind turbines, a batch production is preferred. For this purpose, the necessary for the establishment of the anchoring elements metal racks are placed in the harbor on the deck of the ship and filled a corresponding amount of binder into the bunker of the ship and optionally a lot of aggregate in other bunkers of the ship. The ship then drains to the erection site of the anchoring elements. With its loading crane it lets down the first metal frame for the establishment of a first anchoring element on the seabed. Before, during or after settling of the metal frame on the seabed begins the production of fresh concrete in the ship-borne mixing plant with the entrained binder component and with the seawater taken from the sea as mixing water.

In addition, the aggregate supply with the suction dredger can start at regular intervals in order to fill the designated bunker with sea gravel and to start to drain it. The first ready fresh concrete is then with the Concrete delivery system filled in the sunken on the seabed metal frame, which also serves as formwork. For this purpose it is externally provided with a preferably water-permeable wall, for example a reinforced textile fleece. Continuously, the individual anchoring elements are now erected in the same way, with the unclassified aggregate, ie the sea gravel taken from the seabed and brought in via the suction dredger, being used as soon as necessary for further concrete production. The mixing water is always seawater. The concrete production and concreting work can be carried out continuously and quickly without major interruptions to the supply of aggregate and fresh water. The construction times are significantly reduced.

The inventive method is also suitable for the construction of concrete structures near the sea on land, the corresponding mixing plant and required for material storage bunkers can be land-based. However, unclassified sea gravel from a submarine deposit in combination with sea water is also used as mixing water in this case, so that natural resources or expensive replacement materials and energy can also be saved here.

Further details of advantageous embodiments of the invention will become apparent from the drawings, the description or claims. The description is limited to essential aspects of the invention and other circumstances. The drawings show further details which are to be used as a supplement. Show it:

1 shows a production ship during bunkering, a suction dredger and foundations to be built at sea in a ner schematic top view in a compressed representation,

FIG. 2 shows the material flow in the process carried out on the production vessel,

FIG. 3 shows the production vessel when erecting a ballast body,

Figure 4 shows the suction dredger in the removal of sea gravel and

Figure 5 shows the production ship in a schematic representation.

In fact, in Figure 1, three are relatively wide, i. Sea areas 1, 2, 3 separated by several or several tens of kilometers from one another. Sea area 1 is adjacent to a harbor. The sea area 2 is relatively far off the coast and represents a production area in which concrete structures 4, for example in the form of ballast bodies 5, 6, 7 are already built and / or still to be built. The purpose of a production ship 8, which is still in the port 1 in the representation of Figure 1. During production, it occupies the dashed position in marine area 2.

In the again more or less distant sea area 3, a suction dredger 9 is placed, which serves for the extraction of sea gravel from a mining site on the seabed. It has for this purpose a corresponding technical equipment 11, as it is symbolically illustrated in Figure 4. The suction dredger 9 may periodically start the production ship 8 to transfer the recovered sea gravel 14 as an aggregate for concrete production.

The production ship 8 is illustrated separately in FIGS. 3 and 5. These representations are schematized. The production ship 8 is symbolized in Figure 5 only on the basis of the rough outline of his hull with the omission of all other construction and installations.

The production ship 8 includes a plant 15 for the production of fresh concrete from a brought by land binder component and additives and sea water and sea gravel. For this purpose, the system 15 has one or more storage containers 16 for the binder component, for example cement, fly ash and additives. The cement and the Fly ash can be stored in various storage containers or as a ready-made binder component in a reservoir. Furthermore, the production vessel 8 has a mixing plant 17 suitable for concrete production. Preferably, in particular their coming into contact with the fresh concrete components made of seawater resistant material. This also applies to all subsequent to the mixing plant 17 components, for example, to the concrete conveyor 18 and one of the mixing plant 17 to the concrete conveyor 18 leading line and a leading away from the concrete conveyor 18 line leading to an apparent from Figure 3 concrete conveyor line 21 leads.

The production ship 8 preferably carries a plurality of bunkers 22 for storage with unclassified sea gravel. These bunkers 22 also serve to drain the sea gravel, i. its separation from the rinse water, which was brought to the suction dredger 9. For this purpose, the bunker 22 initially serve as settling vessels, being provided with outlets for the excess water. In addition, precipitating seawater can be supplied as mixing water to the mixer. Alternatively, seawater can be taken directly from the environment of the production ship 8 and preferably fed to the mixing plant 17 without separate treatment.

The bunkers 22 are filled at port stays with interim, unclassified sea gravel. About a conveyor and metering the bunker 22 are connected to the mixing plant 17. The summons of sea gravel at harbor stays in the bunker 22 allows an immediate start of production after taking the default position at sea. By "unclassified sea gravel" is meant the gravels that have not been subjected to a separate classification after degradation, in particular containing all grain sizes up to a maximum grain size in naturally occurring mixture, if any, oversize (eg> 32 mm) is sorted out.

Dosing devices not further illustrated in the drawing are e.g. provided between the aggregate silos 16, 22, 27 and the mixing plant 17 and for metering in additives and mixing water.

With the production ship 8 described so far, the construction of ballast bodies 5 or other subsea structures is carried out as follows:

The production vessel 8 loads, as illustrated in Figure 1, first ashore the binder component for a longer production cycle. There are the reservoir 16, preferably completely filled. In addition, the aggregate silo plant can be filled with unclassified marine gravel extracted from the sea.

The ship then runs out. In the scheme of Figure 1, it starts directly to the production site. The production then begins immediately, as indicated in Figure 3, first with a loading crane one or more metal scaffolds 29 are lowered to the seabed. The metal scaffolds wrap the concrete body to be produced and stiffen it, allowing excess water to drain off. The concrete, if necessary, can be cooled via the filling pipe 21 in order to reach the metal frame at a temperature which is close to that of the seawater. Thus, the subsequent heating by hydration and any resulting cracking reduced fertilizer. The metal scaffolding will now be filled one after the other with concrete. The concrete consists of seawater and gravel and brought binders. It forms a solid concrete body without rebar. The metering and feeding device provided on the conveyor systems 28 to the mixing station and the mixing station 17 as well as the conveyor system for the fresh concrete, which can advantageously operate under computer control, ensure a consistent concrete composition.

The produced ballast bodies 5 can each have up to a thousand cubic meters volume and more. If the loading capacity of the production ship 8 is greatly increased for the transport of the binder component, i. Cement, fly ash and additives, such as setting accelerator, setting slower, condenser and the like used, several to many such foundations can be created sequentially without interrupting production.

FIG. 2 illustrates the resulting logistical expenses in a material flow diagram. As can be seen, the volume and weight of the land-derived stream is substantially less than the flow of the concrete produced. By far the largest proportion comes from sea in terms of weight and quantity and thus does not have to be transhipped into port facilities and transported by ship.

The inventive method for the construction of concrete structures assumes that these concrete structures are later in contact with salt water or built in such. For this purpose, aggregates are used which are at the same salt content as the seawater. Likewise seawater is used as mixing water. It can be thus Be permanent ^¬ tonbauwerke build ship based at sea with low transport costs.

Reference numerals:

1 marine area, sharks

2 marine area

3 sea area

4 concrete structure

5 ballast body

6

7

8 production ship

9 suction dredger

10 proboscis

11 equipment

12

13 seabed

14 gravel

15 attachment

16 reservoir

17 mixing plant

18 concrete conveyor

19

20

21 filling tube

22 aggregate bunker

23 metal scaffolding

Claims

Claims:

1. A method of constructing concrete structures at a site on or in seawater, comprising the steps of:

Providing at least one land-generated binder component intended for mixing concrete at the site of use, the binder component containing at least one binder,

Extraction of aggregate by mining from a reservoir in contact with seawater;

Intake of seawater from the sea;

Mixing the binder component with the aggregate obtained under seawater with the addition of the absorbed seawater as mixing water to produce a pumpable fresh concrete at the site; and

Conveying the fresh concrete to the installation site.

2. The method of claim 1, wherein for providing the land-generated binder component at the site, the binder component is loaded in a harbor on a ship (8) and spent with this at the site.

3. The method of claim 2, wherein, when the binder component contains a plurality of raw materials, the individual raw materials are transported separately in a ship in separate silos.

4. The method of claim 2, wherein, when the binder component contains a plurality of raw materials, the individual raw materials ready in a ship (8) are transported as a mixture in the same storage containers (16).

5. The method of claim 1, wherein for the extraction of seaweed gravel is taken from the seabed in the vicinity of the site.

6. The method of claim 5, wherein the sea gravel is then dewatered to obtain a water content of less than 10% by mass, preferably less than 8% by mass, based on the total mass of the aggregate.

A method according to claim 1, wherein the marine gravel recovered by mining is used unclassified as an aggregate.

8. The method of claim 1, wherein particles are obtained with a larger grain diameter than 32 mm from the aggregate obtained from the sea deposit.

9. The method of claim 1, wherein exclusively sea gravel is used as aggregate and sea water as mixing water for the production of the concrete at the place of use.

A method according to claim 1, wherein fresh water added to the land-collected or treated binder component is added to the mixing water when the salt content of the seawater is more than 3%.

11. The method of claim 1, in which exclusively seawater is used as mixing water.

12. The method of claim 1, wherein the binder component as a binder fly ash, insbesondre hard coal filter ash contains.

13. The method of claim 1, wherein the prefabricated binder component as the main component contains cement.

14. The method of claim 12 and 13, wherein the ratio of fly ash to cement is preferably 1: 1.

15. The method of claim 1, wherein at least one stabilizer, in particular an underwater compounding agent and at least one flow agent, in particular a Hochleistungsverflüssiger belong to the concrete formulation.

16. The method of claim 1, wherein the fresh concrete is conveyed to promote its installation location continuously under pressure through a pipe leading to the installation site.

17. The method of claim 1, wherein the concrete flow is cooled when being fed through the pipe.

18. The method of claim 1, wherein the fresh concrete is poured into a formwork of an anchoring element (29) having a steel structure for probation and for receiving pressure and / or tensile loads.

19. Plant for carrying out the method according to one of the preceding claims,

with a mixing station (17) for mixing aggregate, water, additives and binders to produce a workable concrete,

with at least one storage container (16) for receiving a ready-made binder component,

with a device (12) for extracting sea gravel from a submarine deposit for transporting the same to the production ship (8) with mixing station (17),

with a pumping device for the extraction of seawater and for supplying it to the mixing station (17),

with a metering and feeding device (28) for the metered feeding of the components to the concrete mixing device (17) and

with a concrete conveyor (18) for conveying the workable fresh concrete to the seabed.

20. Plant according to claim 19, characterized in that the mixing station reservoir (22) are connected upstream of seawater and sea gravel.

21. Plant according to claim 19, characterized in that the device for the removal of sea gravel is formed by a suction dredger.

2. Plant according to claim 19, characterized in that it is constructed on a production ship equipped therefor (8).