EP3607147A1

EP3607147A1 - Offshore structure

Info

Publication number: EP3607147A1
Application number: EP18748873.9A
Authority: EP
Inventors: Karlheinz Daum; Daniel Bartminn; Claus Linnemann; Collin BILLINGTON
Original assignee: Innogy SE
Current assignee: RWE Renewables Europe and Australia GmbH
Priority date: 2017-08-11
Filing date: 2018-07-19
Publication date: 2020-02-12
Anticipated expiration: 2038-07-19
Also published as: EP3607147B1; WO2019029973A1; DK3607147T3; US11008727B2; US20200173133A1; PL3607147T3; TWI771453B; DE102017118375A1; TW201910593A

Abstract

The invention relates to an offshore structure having a foundation structure, wherein the foundation structure comprises at least a first and a second profile, the first profile takes the form of a pile (6) and the second profile takes the form of a pile sleeve (7), the second profile encloses the first profile over a penetration length, wherein an interspace (8) is formed between the first and the second profile, the interspace (8) has a filling of grouting compound over the entire penetration length, shear elements are provided on the first and/or the second profile, the shear elements extend into the interspace (8) and effect an axial load transfer into the filling of grouting compound, the shear elements are provided only over a first partial length L1 of the penetration length, and the first partial length L1 is between 65 and 90% of the total penetration length and a second partial length L2 is free of shear elements, wherein the second partial length L2 forms, in the installed position, the upper length of the penetration length.

Description

Offshore construction

The invention relates to an offshore structure with a foundation structure, wherein the foundation structure has at least a first and a second profile, the first profile as a post and the second profile is formed as a pile sleeve, the second profile surrounds the first profile over a Durchdringungs ^¬ length , wherein a gap between the first and the second profile is formed, the gap over the entire penetration length a Vergussmassenfüllung on ^¬ , on the first and / or the second profile thrust elements are provided and the thrust elements extend into the space and an axial load transfer effect in the casting compound filling.

In particular, the invention relates to a potted connection to an offshore structure. Such a molded connection is referred to in the jargon as a so-called "grouted joint." Grouted joints are design elements that are decisive for the structural integrity of offshore constructions, which are usually the only connection between a foundation structure or a foundation and a supporting structure for example, in so-called monopile foundations between the monopile and a transition piece ^¬ (transition piece). grouted joints are found additionally, for example in Jacket foundations, comprising, as profiles Piles and pile sleeves. in particular, in the formation of offshore wind turbines casting compound compounds of the type mentioned play an essential role.

These compounds usually comprise two cylindrical steel tubes of different diameter, which are connected by a grout. The smaller diameter tube is commonly referred to as a pile, while the larger enclosing tube is referred to as a pile sleeve or sleeve. The remaining between the pile and the sleeve gap is filled with a grout or a potting compound, which is referred to in the jargon as Grout. Potting compounds or potted compounds of this type are used primarily to remove axial loads of the structure in the seabed. The compressive strength of the potting compound after it has hardened is decisive for the structural behavior of potted compounds.

A significant increase in the bearing strength of molded connections is achieved in the prior art by the use of shear ribs, which also allow Redu ^¬ cation of the required Vergusslänge or Durchdringungslänge. Push ribs are ribs, projections, webs or the like, which are attached to the mutually facing sides of the profiles and which protrude into the space between the profiles so that they are enclosed by the potting compound. Through the use of shear ribs axial loads are removed via the contact surfaces in the grout. The size of the thrust-transmitting contact surfaces is thereby increased.

In the prior art basically differentiated compounds with and without shear ribs are distinguished, the use of shear ribs has been found to be advantageous. Investigations on the carrying capacity of potted Connections (see, for example, the dissertation "Concrete Techno ^¬ logical Influence on the Structural Behavior of Grouted Joints" ISBN 978-3-936634-05-1) come to the conclusion that the compressive strength and rigidity of the grout, the geometry of the ^¬ steel pipes and the cast space, the surface is precisely ^¬ accuracy of the steel pipes, in particular the height and spacing of the shear web and the Vergusslänge the profiles or steel ^¬ pipes play a role.

In practice it has been shown that despite optimization of Vergusslänge, the geometry of the shear web and other measure ^¬ it took to failure encapsulated compounds coming. The invention is therefore based on the object to provide an offshore structure or a potted connection to an offshore structure, which is improved in terms of carrying and failure behavior. The object is solved by the features of claim 1. Advantageous embodiments of the invention will become apparent from the dependent claims.

One aspect of the invention relates to an offshore structure with a foundation structure, wherein the foundation structure has at least a first and a second profile, the first profile as a post and the second profile as a pile sleeve is ^¬ forms, the second profile of the first profile over a

Penetration length encloses, wherein a gap between seeing the first and the second profile is formed, the gap over the entire penetration length has a Ver ^¬ casting mass filling, on the first and / or the second profile thrust elements, for example in the form of shear ribs or the like are provided , the thrust elements extend into the gap and an axial load transfer in cause the Vergussmassenfüllung, the thrust elements are provided only over a first part length of the penetration length, wherein the first part length between 65 and 90% of ge ^¬ total penetration length and a second part length is free of thrust elements, the second part length of the installation position in the upper length the penetration length forms.

The Applicant has found in experiments that a major cause of the failure or fatigue of Vergosse ^¬ nen compounds are in the potting compound diagonally forming pressure struts, which lead to cracking in the potting compound and in particular in the upper part of the potting length or the Durchdringungslänge cause the potting ^{compound to} escape from the area of the enclosure of the profiles. First loss of encapsulant from the enclosure results in a significant reduction in bearing capacity, which can ultimately result in the failure of the molded joint.

This diagonally forming struts generate preferably on the underside of pusher elements corresponding reac ^¬ tion forces, so that it has surprisingly been found to be particularly advantageous to provide the pushers only over a partial length of the penetration length, and in particular ^¬ sondere that region of the penetration length or Vergusslänge, in the installation position of the profiles above befin ^¬ det to keep free of pushers. This is advantageously a loss of potting compound or a

Swelling or pushing out of the potting compound from the enclosure of the profiles prevents, whereby the bearing resistance of the molded connection is significantly improved.

Particularly advantageous is a design of vergos ^¬ senen connection or the offshore structure has proven, in which the second part length has a length which is between the one and two times the width of the gap. The gap between the profiles may be, for example, about 500 mm wide. The diameter of the second profile may for example be about 2.5 to 3 m.

As a potting compound, for example, a hydraulically abbin ^¬ denominated potting compound, such as a high-strength concrete, before ^¬ seen. The profiles are preferably formed as cylindrical steel tubes from ^¬ , wherein a steel tube is designed as Pile and the other steel tube ^¬ sleeve. The profiles can be part of a connection between monopile and transition piece of an offshore structure.

The profiles may alternatively be part of establishing an offshore structure with a jacket.

In an advantageous variant of the offshore structure in accordance with the invention it is provided that the first profile and / or the second profile on the second part length of the interim have ^¬ c region facing side of the adhesion-loading coating. As a result, it is possible to ensure that the shear stresses arising from a relative movement of the profiles only occur over the first partial length of the penetration length or only over a first partial length of the penetration

Potting length are introduced into the potting compound. In this way, it is ensured that in the upper region of the molded connection, a potting compound plug remains whose integrity is not impaired by shear stresses introduced into the potting compound.

Applicant's experiments have shown that cracks in the casting compound pouring capacity hardly play a role, if these cracks only in the first Part length of the penetration length or in the first part length of the potting length occur. The plug then reliably prevents leakage of the potting compound from the enclosed area of the profiles or from the space between the profiles.

The adhesion-reducing coating may preferably entwe the ^¬ be provided on the side facing the space inside of the second profile or at the side facing the space outside of the first profile, depending on which profile is subject to a compressive and tensile stress in the axial direction. For example, with a jacket, this may depend on whether the jacket was attached by pre-piling or post-piling.

For example, it can be provided that between the first profile and / or the second profile and Vergussmassenfül ^¬ ment over the second part length of the penetration length or Vergusslänge a layer of an elastic material, preferably of an expanded thermoplastic material is provided.

The Vergussmassenfüllung may over the first part length of the penetration length a first potting compound and over the second part of the penetration length a second Verguss ^¬ mass, wherein the second potting compound has a higher tensile and / or compressive strength than the first potting compound ^¬ . For example, the second sealing compound faserver ^¬ strengthens or armored can be. For example, the second

Potting compound be designed as fiber concrete.

Appropriately, it is provided that the second potting compound has a higher ductility than the first potting compound. In principle it can be provided that the Vergussmassenfüllung over the second part length (L2) receives an insert member which is selected from a group of Einsatzbau ^¬ parts comprising precast concrete elements, steel profiles and polymer merbaustoffe, wherein the insert component has a higher tensile and or compressive strength than having the Vergußmass.

Particularly advantageous is a design of Vergos ^¬ senen connection has been found on the offshore structure, in which the gap is at least partially closed on the upper side in the installed position. It can be provided that the pile sleeve comprises a top, an inwardly hervorste ^¬ Henden collar covering an upper end in the installed position ^¬ side of the space partially and thus a

Stepping out or swelling out, for example, prevents brittle potting compound.

Alternatively it can be provided that the pile has a collar or collar which closes the intermediate space on the front side.

Alternatively or additionally, it may be provided that a reinforcement is attached to the first profile or to the second profile, which extends over the second partial length of the penetration length. The reinforcement is expediently provided on that profile which is not subject to an alternating tensile and compressive load.

The invention will be described below with reference to an embodiment shown in the drawings.

Show it: FIG. 1 shows a schematic representation of a part of an offshore wind power plant with potted connections, which were created according to the principle of post-piling, FIG. 2 shows a schematic representation of an offshore wind energy plant with potted connections, which are based on the principle of pre-piling. Piling were created,

FIG. 3 a shows a partial section through a potted connection of the foundation of the offshore wind energy plant illustrated in FIG. 2, which schematically illustrates a shear stress as compressive stress of the molded connection,

FIG. 3b shows a partial section through a potted connection of the foundation of the offshore wind energy plant illustrated in FIG. 2, which schematically illustrates a shear stress as tensile stress of the potted connection, and FIG

Figure 4 is a section through a molded connection according to the invention, showing the arrangement of the pushers.

The invention relates to an offshore structure 1 and in particular a potted connection to an offshore structure 1. The invention will be described below with reference to an offshore structure 1 with a jacket foundation. As already mentioned, the principle of the molded connection according to the invention can be applied to various types of connections to offshore structures. The offshore structure 1 includes, for example, a tower structure 2, a transition piece 3, a so-called Yes ^¬ cket 4 and anchoring of the jacket 4 in the seabed 5 in the form of piles 6 (Piles) and pile sleeves 7 (Sleeves). The offshore construction 1 shown in Figure 1 was established by the so-called ^Pre-¬ Piling, that the piles were 6 using a template and appropriate tool in the subsoil 5 driven. The pile sleeves 7, which are attached to the jacket 4, were placed on the driven piles 6, which penetrate the pile sleeves 7. An intermediate space 8 or annular space between the piles 6 and the pile sleeves 7 was cast with a hardenable potting compound 11, for example a fiber concrete or the like.

Another variant of the pile foundation is shown in Figure 2 Darge ^¬ represents. This variant of the foundation is generally referred to as post-piling. The pile sleeves 7 are first driven into the seabed 5. In this, the feet of the jacket, which are each designed as a pile 6, used. The space between the pile 6 and the pile sleeve 7 is also filled with a curable potting ^¬ mass. The axial forces introduced via the jacket 4 into the seabed are removed via the potting compound into the piles 6 (FIG. 1) or into the pile sleeves 7 (FIG. 2).

FIGS. 3a and 3b show the typical load on the casting compound 11 when tensile or compressive forces are introduced, for example, over the pile 6 in the case of a foundation, as shown in FIG. With the drawn in Figures 3a and 3b arrows ^¬ 9, the loading direction is indicated. In Figure 3a, the inner profile is a cylindrical pole 6, while the outer profile which closes the inner profile by ^¬, the pile sleeve 7 forms. The gap 8 is filled with a grout or a hydraulically setting potting compound 11. In the introduction of compressive forces as Shear stress as it is Darge ^¬ represents, for example, in Figure 3a, are formed diagonal struts 10 between the pole 6 and the pile sleeve 7, which in some circumstances, that the casting compound is expressed 11 upwardly out of the gap 8 of origin. The tendency of the potting compound 11 to move is indicated by the arrows 13

The Applicant has found that in particular the ribs ^¬ sammenwirken the strut 10 with the underside of thrust 12 or differently shaped thrust elements opposes diagonal reaction forces generated that cause the encapsulant becomes brittle 11 and expelled upwardly from the gap 8 becomes, as indicated by the arrows 13. In particular, the loss of emerging from the Um- closure of the profiles potting compound 11 ultimately causes a failure of the potted compound. 3a shows the course of loading upon initiation of axial pressure forces, whereas Figure 3b shows the load curve for Einlei ^¬ th illustrated by axial tensile forces.

Figure 4 shows a partial longitudinal section through a molded connection according to the invention. The formation of the grouted joint in the form of two interpenetrating cylindrical steel profiles as pile 6 and pile sleeve 7 corresponds to the design according to FIGS. 3 a and 3 b. The pile 6 and the pile sleeve 7 penetrate each other over a penetration length L total _/ corresponds to the potting length or the height of the potting compound 11 located in the gap 8. The penetration length L total is subdivided into a first partial length LI and into a second partial length L2, wherein the second partial length L2 is the partial length in the installed position of the pile sleeve 7 and the first partial length LI forms the lower partial length. Over the first part length LI of the penetration length extending at the gap 8 side facing the pile sleeve 7 and at the gap 8 facing outside of the pile 6 thrust elements, for example in the form of thrust ^¬ ribs 12 or other geometries that protrude into the space 8 and are enclosed by the potting compound 11. According to the invention, the partial length L2 of the penetration length is free of thrust elements. The push ribs 12 are vorgese ^¬ hen only in the region of the first part length LI of the penetration length. The height of the second part of length L2 corresponds to approximately one to two times the width of the gap 8 (0.5 x (In ^¬ nendurchmesser pile sleeve outer diameter minus pole)).

LIST OF REFERENCE NUMBERS

1 offshore structure

2 tower construction

3 transition piece

4 jacket

5 seabed

6 stake

7 pile sleeves

8 space

9 arrows

10 struts

11 potting compound

12 push ribs

13 arrows

LI first part length

L2 second part length

L total = Li + L2

Claims

claims

1. Offshore structure (1) with a foundation structure, wherein the foundation structure has at least a first and a second profile, the first profile as a post (6) and the second profile as a pile sleeve (7) is formed, the second profile of the first Profile surrounds a penetration length, where ^{¬ is formed} at a gap (8) between the first and the second profile, the gap (8) over the entire penetration length (L total) on a Vergussmassenfüllung ^¬ , at the first and / or second profile thrust elements are provided, the thrust elements extend into the intermediate space (8) and cause an axial load transfer in the Verguss ^¬ mass filling, the thrust elements are provided only over a first part length (LI) of the Durchdringungslänge, the first part length (LI) between 65 and 90% of the total penetration length (L total) and a second partial length (L2) is free of thrust elements, wherein the second partial length e (L2) which forms the upper length of the penetration length in the installation position.

2. offshore construction according to claim 1, characterized in that the second partial length (L2) has a length that we ^¬ nigstens the width of the gap (8), preferably two times the width of the gap is.

3. Offshore structure according to one of claims 1 or 2, characterized in that the first profile and / or the second Pro ^¬ fil over the second part length (L2) on the said gap (8) facing side have a adhesion-reducing coating.

4. Offshore construction according to one of claims 1 to 3, characterized in that between the first profile and / or the second profile and the Vergussmassenfüllung over the second part length (L2) of the penetration length (L total) a layer is provided from an elastic material, preferably from an expan ^¬ dierten thermoplastic material.

5. Offshore construction according to one of claims 1 to 4, characterized in that the Vergussmassenfüllung over the first part length (LI) of the penetration length a first potting compound and the second part length (L2) of the penetration length has a second potting compound and that the second potting ^¬ mass has a higher tensile and / or compressive strength than the first potting compound.

6. Offshore construction according to claim 5, characterized in that the second potting compound has a higher ductility than the first potting compound.

7. Offshore structure according to one of claims 1 to 6, characterized in that the Vergussmassenfüllung over a second partial length (L2) of the penetration length fiber-reinforced and / or reinforced.

8. Offshore construction according to one of claims 1 to 7, characterized in that the Vergussmassenfüllung over the second part length (L2) receives an insert member which is selected from a group of insert components comprising precast concrete elements, steel profiles and polymer materials, wherein the onset ^{¬ set} component a has higher tensile and or compressive strength than the potting.

9. Offshore construction according to one of claims 1 to 8, characterized in that the intermediate space (8) is at least partially closed on the upper side in the installation ^¬ position upper end.

10. Offshore construction according to one of claims 1 to 9, characterized in that the pile sleeve (7) has an upper, in ^¬ nen projecting collar, which partially covers a mounting position in the upper end side of the gap.

An offshore structure according to any one of claims 1 to 9, wherein a reinforcement is attached to the first profile or to the second profile which extends over the second partial length (L2) of the penetration length.

12. Offshore structure according to one of claims 1 to 10, characterized in that the thrust elements are selected from a group comprising thrust ribs, shear bars or ^¬ same.