U.S. patent application number 13/213248 was filed with the patent office on 2012-05-03 for base structure for off-shore wind turbines and method for building thereof.
This patent application is currently assigned to HILGEFORT GMBH ANLAGENKOMPONENTEN UND APPARATEBAU. Invention is credited to Frank Baumfalk.
Application Number | 20120107055 13/213248 |
Document ID | / |
Family ID | 44719277 |
Filed Date | 2012-05-03 |
United States Patent
Application |
20120107055 |
Kind Code |
A1 |
Baumfalk; Frank |
May 3, 2012 |
BASE STRUCTURE FOR OFF-SHORE WIND TURBINES AND METHOD FOR BUILDING
THEREOF
Abstract
The invention relates to a base structure for an off-shore wind
power installation having a plurality of base piles wherein each
base pile has a driving pile which is guided in its interior at
least portion-wise for anchoring in the seabed, and at least one
support structure for mounting a pylon of a wind power
installation, wherein the support structure connects the upper ends
of the base piles together. Furthermore the base pile and the
driving pile have a region of an overlap on a predetermined
lengthwise portion, wherein in the overlap region of the piles the
gap between the piles and in part beneath and above the overlap
region the free internal cross-section of the piles are filled with
a hardening filling material. The invention also relates to a
method of erecting a base structure for an off-shore wind power
installation and an aligning tool.
Inventors: |
Baumfalk; Frank; (Dotlingen,
DE) |
Assignee: |
HILGEFORT GMBH ANLAGENKOMPONENTEN
UND APPARATEBAU
Dinklage
DE
|
Family ID: |
44719277 |
Appl. No.: |
13/213248 |
Filed: |
August 19, 2011 |
Current U.S.
Class: |
405/228 ;
405/232 |
Current CPC
Class: |
E02D 5/40 20130101; E02B
2017/0091 20130101; E02D 27/42 20130101; Y02E 10/72 20130101; E02D
13/04 20130101; E02D 27/425 20130101; E02B 2017/0073 20130101; E02D
27/52 20130101; F05B 2240/95 20130101; Y02E 10/727 20130101; E02B
17/027 20130101; E02D 7/20 20130101; F03D 13/22 20160501; E02B
17/0004 20130101; E02B 17/0008 20130101; E02B 2017/006
20130101 |
Class at
Publication: |
405/228 ;
405/232 |
International
Class: |
E02D 13/00 20060101
E02D013/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 20, 2010 |
DE |
10 2010 035 025.7 |
Aug 20, 2010 |
DE |
10 2010 035 035.4 |
Claims
1. A base structure for an off-shore wind power installation having
at least a plurality of base piles wherein each base pile (2, 3, 4)
has a driving pile which is guided in its interior at least
portion-wise for anchoring in the seabed, and at least one support
structure for mounting a pylon of a wind power installation,
wherein the support structure connects the upper ends of the base
piles together, characterised in that the base pile (2, 3, 4) and
the driving pile (11, 12, 13) have a region of an overlap on a
predetermined lengthwise portion, wherein in the overlap region
(25) of the piles the gap (29) between the piles and in a part
beneath and above the overlap region (25) the free internal
cross-section of the piles (2, 3, 4, 11, 12, 13) are filled with a
hardening filling material (30).
2. A base structure as set forth in claim 1 characterised in that
the base pile (2 through 4) has a bottom ring (26), preferably with
a seal which seals off the gap (29) relative to the driving pile
(11, 12, 13).
3. A base structure as set forth in one of claims 1 and 2
characterised in that the base pile (2 through 4) has an inner tube
providing its inner peripheral surface and an outer tube providing
its outer peripheral surface, wherein a core material is arranged
between the inner tube and the outer tube.
4. A base structure as set forth in one of claims 1 through 3
characterised in that the driving pile (11 through 13) has a
bulkhead (28) which is arranged at a spacing beneath the overlap
region (25) and which closes off the free internal cross-section of
the driving pile (11, 12, 13).
5. A base structure as set forth in claim 4 characterised in that
the driving pile (11 through 13) in its pile wall beneath the
bulkhead (28) has at least one opening (32) for air venting.
6. A base structure as set forth in one of claims 2 through 5
characterised in that the bottom ring (26) extends radially beyond
the base pile (2, 3, 4) and is connected thereto by support struts
(34).
7. A base structure as set forth in one of claims 1 through 6
characterised in that the driving pile (11 through 13) is provided
at least portion-wise on the inside of the pile wall with
reinforcement (31).
8. A method of erecting a base structure for an off-shore wind
power installation, in which a plurality of and preferably three
base piles (2, 3, 4) provided with driving piles (11, 12, 13) are
pre-assembled with at least one support structure (5, 15)
comprising bars (6, 7, 8, 16, 17, 18) to form a construction part,
the pre-assembled construction part is transported to the
installation location and placed with its base piles (2 through 4)
leading on the seabed (10), than the driving piles (11 through 13)
are driven into the seabed (10) and a base portion anchored in the
seabed (10) is produced, characterised in that finally a hardening
filling material (30) is introduced into the base portion into at
least the overlap region (25) of the piles and a portion above and
below the overlap region and thus a solid base structure (1) is
formed.
9. A method as set forth in the classifying portion of claim 8 or
as set forth in claim 8 characterised by the step: aligning the
base portion in such a way that a central axis of a central
mounting (9) for mounting the pylon of a wind power installation is
oriented substantially vertically, wherein a filling material (30)
is introduced preferably after the alignment operation.
10. A method as set forth in claim 9 characterised in that the
alignment operation includes: displacing at least one, preferably
two of the three, base piles (2, 3, 4) relative to the driving pile
(11, 12, 13) by means of an aligning ram (100) arranged completely
within and/or above the base pile (2, 3, 4).
11. A method in particular as set forth in claim 10 or at least one
of preceding claims 9 through 11 and further including the steps:
introducing the aligning ram (100) from an upper end of the base
pile (2, 3, 4), which is above the surface of the sea, into the
base pile (2, 3, 4), contacting a ram head (106) of the aligning
ram (100) with the driving pile (11, 12, 13), bringing a support
device (105) of the aligning ram (100) into engagement with the
base pile (2, 3, 4), and extending a portion of the aligning ram
(100) to displace the base pile (2, 3, 4) relative to the driving
pile (11, 12, 13).
12. A method as set forth in claim 11 characterised in that
extension of the aligning ram (100) is effected hydraulically.
13. A method as set forth in one of claims 11 and 12 and further
including the step: introducing filling material (30) through a
passage (112) in the aligning ram (100) into the driving pile (11,
12, 13) and/or the overlap region.
14. A method as set forth in one of claims 8 through 13
characterised by the step: closing, preferably air-tightly sealing,
the upper open end of at least one base pile (2, 3, 4) by means of
a closure device (150).
15. An aligning tool including an aligning ram (100) with a ram
tube (118), a ram head (106) connected to the ram tube for coming
into contact with a driving pile (11, 12, 13), and a support device
(105) for supporting a base pile (2, 3, 4).
Description
[0001] The invention relates to a base structure for an off-shore
wind power installation having at least a plurality of base
foundation piles, wherein each base pile has a driving pile which
is guided in its interior portion-wise for anchoring in the seabed,
and at least one support structure for mounting the wind power
installation.
[0002] The invention also concerns a method of erecting a base
structure for an off-shore wind power installation.
[0003] Known base or foundation structures for hydraulic structures
such as for example for off-shore wind power installations usually
form the transition from the structure to the ground, in the
present case the hydraulic structure to the seabed, and are
intended to ensure secure anchoring in the seabed. Specifically
off-shore wind power installations are increasingly being located
at some distance from the coast and as a result frequently in
depths of water of up to 50 meters or more. By virtue of the
ambient conditions prevailing at such an installation location and
the wind and wave loads which generally act on the base structure
and the hydraulic structure, correspondingly high demands are made
on anchorage of the base structure in the seabed and the base
structure carrying the hydraulic structure itself.
[0004] EP 1 673 536 B1 describes for example a base structure for
an off-shore wind power installation, having a plurality of base
piles with respective driving piles which are at least portion-wise
guided in the interior of the respective base piles, for anchorage
in the seabed. The base structure further has at least one support
structure for mounting the pylon of the wind power installation,
wherein the support structure connects the upper ends of the base
piles together. In that case, after piling of the driving piles, a
predetermined lengthwise portion is produced, in which the driving
piles are received by the base piles. To prevent relative movement
between the base piles and the driving piles and thereby possibly
cause loosening of the anchorage of the base structure in the
seabed, an adhesive join is made in a part of the overlap region
between the outside of the driving pile and the inside of the base
pile. The relatively narrow adhesive join between the outside of
the base pile and the inside of the driving pile means that on the
one hand there is the risk that the adhesive tears and thus the
driving pile is again movable relative to the base pile. In
addition, it is in the region of the seabed that the highest moment
caused by the wind and wave loads acts on the base and driving
piles of the base structure so that the constant changes in load
shortly beneath the overlap region of the piles can result in
deformation and possibly bending of the walls of the driving piles,
which at any event can have a detrimental effect on the anchorage
thereof and thus on the operationally reliable long-term function
of the base structure.
[0005] Therefore the object of the present invention is to improve
a base structure of the above-indicated general kind such that
deformation phenomena at the piles, by virtue of the load changes
acting thereon, are avoided. The further object of the invention is
to provide a method of erecting a base structure for a hydraulic
structure, which can be carried out in a simplified and reliable
fashion, in particular a method of erecting a base structure, by
means of which the base structure can be aligned in simplified
fashion.
[0006] According to the invention the object is attained by a base
structure having the features of claim 1, and by a method as set
forth in claim 9. Advantageous developments and configurations of
the invention are recited in the claims appendant to claims 1 and
9.
[0007] In the case of a base structure for an off-shore wind power
installation having at least a plurality of base piles, wherein
each base pile has a driving pile guided in its interior at least
in portion-wise manner for anchorage in the seabed, and at least
one support structure for mounting the pylon of a wind power
installation, wherein the support structure connects the upper ends
of the base piles together, it is provided that the base pile and
the driving pile have a region of overlap on a predetermined
lengthwise portion, wherein in the overlap region of the piles, in
at least portion-wise manner, the gap between the piles, and over a
portion of the overlap region and in a part beneath the overlap
region, the free internal cross-section of the driving pile is
filled with a hardening filling material.
[0008] By means of such a strong structure around the overlap
region of the base piles and the driving piles which are
region-wise accommodated by the base piles, in particular buckling
or kinking of the pile walls is advantageously prevented in the
region of the seabed by the filling material which has portion-wise
hardened within the driving pile and between the base pile and the
driving pile. The filling material which extends to beneath the
overlap region in the interior of the driving pile imparts thereto
optimum stiffness over a predetermined part thereof, whereby the
driving pile can be made up from a single-walled tube. The
hardening filling material which preferably respectively extends
from below to above the overlap region, such as for example
concrete, advantageously produces a base structure, by means of
which it is possible without any problem to guarantee an
operationally reliable long-term function of the at least required
period of 20 years.
[0009] Advantageously in a development of the invention it is
provided that the base pile in the foot region has a guide for the
driving pile, which reduces the free cross-section of the base pile
at the inner peripheral surface. The use of a guide has the
advantage that the driving pile is axially movably guided during
the driving operation in particular at the beginning of the driving
works, so that the driving pile is driven into the seabed with its
center line preferably coaxially with respect to the center line of
the base pile. That is intended advantageously to prevent the
driving pile from running out. In that case the guide is provided
approximately over half of the overlap region of the two piles in
the gap between the inside of the base pile and the outside of the
driving pile at least region-wise over the periphery thereof. The
guide can be for example in the form of a sleeve. Preferably a
plurality of plates are used, the longitudinal axes of which extend
parallel to the center line of the base pile and extend radially
from the inside of the base pile in the direction of the center
line.
[0010] Optionally the base pile has a bottom ring with a seal which
seals off the gap relative to the driving pile, whereby on the one
hand the ingress of sea water, as well as pieces of rock and mud,
in particular into the gap in the region of the guide, is avoided
during and after the pile driving operation. That therefore
prevents unwanted fouling of the portion of the base pile and the
driving pile, that is to be subsequently concrete-filled. On the
other hand the seal in the region of the gap also prevents the
escape of the subsequently introduced filling material. Therefore
the hardening filling material always remains at the same level in
the gap between the base pile and the driving pile and can
accordingly involve a fixed connection to the surfaces of the
respective pile walls. To produce the seal on the bottom ring, it
is possible for example to use a felt or another suitable material
which is suitable for preventing the entry of water or the ingress
of mud. In addition, a bursting disk can be fitted on the bottom
ring from below, which disk effectively closes the free
cross-section of the driving pile which is preferably in the form
of a tube and which is thus downwardly open, and thus already
prevents the entry of sea water when lowering the construction part
serving to produce the base structure, on to the seabed; the
bursting disk is already destroyed by the driving pile which is
preferably driven perpendicularly downwardly, when the construction
part is placed on the seabed but at the latest with the beginning
of the pile driving operation, and in that case the bursting disk
does not represent any impediment for the pile driving operations
to be performed.
[0011] Alternatively it may be advantageous not to provide a seal.
Thus when the base structure is lowered from a ship on to the
seabed water can pass controlledly and uniformly into the base
piles. The risk of a suddenly occurring leak in a sealed base pile
causing a sudden shift in the center of gravity and thus tipping of
the base structure is reduced. The seal and the bursting disk can
then be omitted.
[0012] The base pile preferably has an inner tube providing its
inner peripheral surface and an outer tube providing its outer
peripheral surface, a core material being arranged between the
inner tube and the outer tube. Such a wall structure according to
the invention provides a structurally advantageous possible way of
forming the base piles. The sandwich structure of the pile wall on
the one hand improves the stiffness of the base pile while on the
other hand the amount of steel usually employed to produce the base
pile can advantageously be reduced thereby. Due to the increased
stiffness, both the diameter and also the overall thickness of the
inner and outer tubes can be markedly minimised, which at the same
time advantageously improves the economy of such base structures
according to the invention by virtue of reduced production and
material costs. The core material as the intermediate layer between
the inner and outer tubes is in particular additionally
strengthened with reinforcement which is arranged in the form of
concrete reinforcing steel bars or in the form of a
hollow-cylindrical lattice in the core material. It is provided in
that case that the reinforcement is always completely enclosed by
the core material and is arranged at a spacing relative to the
inside of the outer tube and the outside of the inner tube.
[0013] It is advantageously provided in a development that the
driving pile has a bulkhead which is arranged at a spacing beneath
the overlap region and which closes off the free internal
cross-section of the driving pile. The entry of water or mud by way
of the driving pile which is of a hollow-cylindrical configuration
into the interior of the base pile is avoided by means of such a
bulkhead in the operation of driving the driving pile so that the
free cross-section of the driving pile is filled with seabed only
as far as the bulkhead. In addition the bulkhead serves as a
filling limit for the filling material which is to be introduced
into the driving pile head and which hardens therein and which
imparts improved stiffness to the driving pile. The bulkhead is in
particular a plate body which extends with its plate plane
perpendicularly to the center line of the driving pile and which is
sealingly connected in peripheral relationship to the inside of the
wall of the driving pile, in particular being welded thereto. In
that case the bulkhead is arranged approximately at a spacing
beneath the end of the base pile, that corresponds to the length of
the overlap of the piles.
[0014] To avoid an excessive build-up of pressure in the interior
of the driving pile and thus an unnecessary counteracting force in
the pile driving operation venting of air from the interior of the
driving pile is to be provided. For that purpose in its pile wall
beneath the bulkhead the driving pile has at least one opening.
Accordingly air in the driving pile can escape in the driving
operation so that the constituents of the seabed can rise up in the
free cross-section of the driving pile to below the bulkhead. In
that respect it is advantageous if a plurality of openings are
provided beneath the bulkhead over the length of the driving pile
and at the same time a plurality of openings are arranged in the
pile wall at the same height level distributed around the periphery
of the driving pile. In addition each opening for air venting in
the wall of the driving pile can be sealed with a suitable material
which dissolves for example upon contact with water and thus the
openings are successively opened for air venting purposes in the
longitudinal direction in the wall of the pile.
[0015] In an optional configuration, at its outside peripheral
surface, the driving pile has a radially outwardly extending step
as an abutment against the guide of the base pile, by means of
which the driving pile is brought into contact in positively
locking relationship in the longitudinal direction with in
particular the plates forming the guide at the inside of the base
pile and exerts a holding force perpendicularly downwardly on the
base pile. The step which extends in an annular shape along the
peripheral surface of the driving pile is in particular arranged in
spaced relationship with the upper end of the driving pile so that
there is always a given portion of the driving pile that projects
freely into the base pile above the guide. That provides a gap
between the outside of the driving pile and the inside of the base
pile, into which gap the filling material can be introduced. The
radially outwardly extending peripheral surface of the step can be
at the same time in the form of a guide surface for support against
the inside of the base pile. That further improves guidance for the
driving pile within the base pile and at the same time
advantageously prevents the driving pile from running out in the
pile driving operation. The step can be in particular a flange-like
ring body welded to the outer peripheral surface of the driving
pile.
[0016] Another development provides that the driving pile is at
least portion-wise provided with reinforcement on the inside of the
pile wall. In particular the subsequently introduced filling
material is strengthened by means of the reinforcement, while in
addition its tensile strength is increased and thus the
load-bearing capability of the piles is markedly improved in the
region of the seabed. Specifically forces acting dynamically on the
base structure can be absorbed without any problem by the
reinforced component structure of the base. In particular concrete
reinforcing steel in the form of bars is used as reinforcement,
which are arranged on a predetermined part-circle diameter in
spaced relationship with the inside of the driving pile. In place
of individual bars it is also possible to use a cylindrical
reinforcing cage which extends similarly to a mesh on a uniform
radius around the center line of the driving pile.
[0017] A development of the invention provides that beside the base
piles at least one further partial region is in the form of at
least one tube portion of a bar of the lattice-like support
structure which is composed of a plurality of bars. That
advantageously also achieves increased strength in the lattice-like
support structure which connects the upper ends together and by
means of which the wind power installation is mounted and a direct
connection is made between the base structure and the pylon of the
wind power installation. The number of bars can be reduced, by
virtue of the improved stiffness, by means of the configuration
according to the invention of tube portions of the bars used in the
support structure. A saving of steel material is advantageously
also achieved thereby, in the region of the support structure, with
at the same time improved stiffness thereof. The bars used for
forming the lattice-like support structure are in particular of a
cylindrical cross-section, wherein the configuration of the wall
according to the invention can extend both over the entire length
of a bar and also only over a given bar or tube portion.
[0018] At least one of its end regions each tube portion is
provided with a bulkhead which sealingly closes off at least its
internal free cross-section. That already prevents in particular
the ingress of moisture into the interior of the free tube portion
before assembly to constitute a support structure connecting the
base piles together. Furthermore the bulkhead can additionally
serve as a filling limit for a filling material introduced in the
region of the node points produced in the support structure. In
this connection the bulkhead can be a circular plate body which can
be connected at its periphery to the inside of the inner tube, in a
connection involving intimate joining of the materials involved,
for example by welding.
[0019] It is further provided that each tube portion has a
reinforcement projecting at its end beyond its bulkhead. The
reinforcing steel which is used for example between the outer and
inner tubes of the tube portion accordingly projects beyond the
bulkhead into a filling space for filling material to be introduced
thereinto, the filling space possibly being formed on both sides of
the ends of the tube portion of the bar of the support structure.
When using a hardening filling material the projecting portions of
the reinforcement of the tube portion then involve a connection to
the hardened filling material, that involves intimate joining of
the materials involved, after the filling material has set.
[0020] At least one of its ends each tube portion has an annular
connecting surface extending in a plane oriented perpendicularly to
the center line of the tube portion. A respective tube portion
involving the sandwich structure according to the invention
accordingly always has straight ends extending perpendicularly to
its center line. Each tube portion according to the invention can
be connected to connecting tube portions forming the ends of a
respective bar, by way of the straight ends having a respecting
connecting surface at the ends. The connection of a respective
individually prefabricated tube portion to a connecting tube
portion of conventional nature can in that case be advantageously
easily effected by means of orbital welding devices, wherein the
tube portion and the connecting tube portion are in particular
welded together to form a bar of the support structure.
[0021] A further development of the invention provides that each
tube portion is equipped with tie elements which act parallel to
its center line and which are provided for spanning over at least
one node point formed in the connecting region of two component
parts of the base structure. The use of tie elements in the region
of a node point has the advantage that a respective tube portion
according to the invention is drawn in the direction of a node
point by means of the tie elements which in particular are in the
form of tie bars. Welded seams in the compression region are thus
exposed to reduced load changes whereby at the same time the
fatigue characteristics thereof are advantageously reduced. A
plurality of tie bars are used on a tube portion, the tie bars
being arranged uniformly on a part-circle diameter near the tube
wall of the tube portion. That always ensures an advantageous
application of force in the region of the node points. The tie bars
can be for example arranged with their head end at a bulkhead in a
respective end region of the tube portion. The be elements which in
that case are preferably in the form of tie bars also extend
parallel to the center line of a respective bar of the support
structure for example as far as in a tube portion of a base pile or
a bar extending at an angle thereto.
[0022] There is further provided a method of erecting a base
structure for a hydraulic structure, in particular for an off-shore
wind power installation, in which a plurality of base piles
provided with driving piles are pre-assembled with at least one
support structure comprising bars to form a construction part, the
pre-assembled construction part is transported to the installation
location and placed with its base piles leading on the seabed, then
the driving piles are driven into the seabed and a base portion
anchored in the seabed is produced, and finally a hardening filling
material is introduced into the base portion into at least the
overlap region of the piles and thus a solid base structure is
formed.
[0023] Alternatively the base structure or the base portion is
welded to the support structure only after the base piles have been
set in place and after pile driving of the driving piles.
Preferably connecting bodies are provided for that purpose, by
means of which the support structure can be connected to the base
piles by means of orbital welding.
[0024] A base structure can be produced in a simplified but at the
same time reliable fashion by means of the method steps according
to the invention and the specifically implemented sequence thereof.
Pre-assembly of the base piles and the driving piles respectively
accommodated therein with the support structure to afford a
finished construction part is preferably still effected on land so
that this ensures relatively accurate pre-assembly. The finished
construction part is then lifted on to a floating platform and
transported by means thereof to the predetermined installation
location. The still relatively light construction part with its
piles and the support structures is then lifted with a lifting
apparatus, for example a floating crane, off the platform in one
piece, and lowered with its base piles facing perpendicularly
downwardly until the base piles contact the seabed. After the
lowering operation the driving piles are successively driven into
the seabed with a slender pile driver, thereby providing for firm
anchorage of the construction part and thus producing a base
portion. Finally a hardening material such as for example concrete
is introduced into at least the overlap region of the piles.
Preferably the filling material is introduced both into the free
cross-section of the driving pile in a portion beneath the overlap
region of the piles, into a region above the overlap region, so
that at the same time the filling material also runs into the gap
above the guide of the base pile between the driving pile and the
base pile. After hardening of the filling material, that affords a
base structure which is so strong and firm that it carries without
any problem the dynamic fluctuating loads of wind and waves that
act on the base structure.
[0025] In a development of the invention it can be provided that
after the pile driving operation the hardening filling material is
also introduced into a gap between an inner tube and an outer tube
of a respective base pile and thereafter the upper ends of the base
piles are closed. Subsequent introduction of the filling material
between the inner and outer tubes, in contrast to an operation of
introducing the filling material which has already been effected in
the pre-assembly stage, as a core material between the inner and
outer tubes, gives the advantage that the construction part is of
lower inherent weight and can thus be easily lifted and aligned
upon being loaded on to a floating platform and in the operation of
placing it on the seabed.
[0026] In a preferred development of the method or in a further
aspect of the invention the aforementioned object is attained by a
method of erecting a base structure for an off-shore wind power
installation, in which a plurality of and preferably three base
piles equipped with driving piles are pre-assembled with at least
one support structure consisting of bars to afford a construction
part, the pre-assembled construction part is transported to the
installation location and placed with its base piles leading on the
seabed, then the driving piles are driven into the seabed and a
base portion anchored in the seabed is produced, wherein the method
comprises the step of: aligning the base portion in such a way that
a central axis of a central mounting for mounting the pylon of a
wind power installation is oriented substantially vertically. A
filling material is preferably introduced after the alignment
operation. Preferably alignment of the base portion or the base
structure is effected in such a way that an angular deviation
between the central axis of the central mounting and a vertical
line is less than 2.degree., preferably less than 1.degree.,
preferably less than 0.5.degree.. The pylon of an off-shore wind
power installation is received in the central mounting. Wind power
installations have a high pylon which can exceed 100 m. It is
therefore necessary for the base structure to be aligned
substantially vertically so that the angular deviations are slight.
It is only in that way that a wind power installation can be
securely and reliably installed by means of the base structure.
When driving the driving piles into the seabed it happens that the
latter subsides at places so that the base structure set in place
thereon is not exactly vertically oriented. Previous methods
therefore provide that the central mounting at the upper end of the
support structure is to be subsequently adapted to the base
structure. Such adaptation includes in particular the production of
special connecting flanges which compensate for the angular
inaccuracies. It will be noted however that this is highly
complicated and expensive and requires additional operating steps
and material. That also results in additional connecting locations
between the base structure and the wind power installation to be
mounted thereon, which can later lead to fatigue of the base
structure. Complicated and expensive measures of that kind, such as
in particular the production of connecting flanges, are eliminated
by the base portion or base structure being appropriately
aligned.
[0027] Preferably the alignment operation includes displacing at
least one, preferably two of the three, base piles relative to the
driving pile by means of an aligning ram arranged completely within
and/or above the base pile. Such an aligning ram is preferably in
the form of or has an aligning device. If the base structure has
three base piles, as is particularly preferred, it can be suitably
aligned by displacement of two of the three base piles relative to
the corresponding driving piles. The base piles are accordingly
displaced along the driven-in driving piles by a difference so that
the lifted base piles are then no longer standing on the sea
bottom. The aligning ram, by means of which the corresponding base
pile is lifted, is in that case arranged completely within and/or
above the base pile. It can be arranged substantially in the base
pile and can project out of the base pile at an upper side thereof.
The base piles extend from the seabed or shortly above the seabed
to a position above the surface of the sea. Because the aligning
ram is arranged substantially within and/or above the base pile, it
is not exposed to any flow or any pounding by the waves so that the
operation of positioning such a ram and operating thereon are
substantially simplified.
[0028] In a preferred development the method further includes the
step of: introducing the aligning ram from an upper and of the base
pile, which is above the surface of the sea, into the base pile,
contacting a ram head of the aligning ram with the driving pile,
bringing a support device of the aligning ram into engagement with
the base pile, and extending a portion of the aligning ram to
displace the base pile relative to the driving pile. After the base
structure with the base piles has been placed on the seabed and the
driving piles have been at least partially and preferably
completely driven thereinto, the aligning ram is introduced into
the base pile from the upper open end thereof. In that case the
aligning ram is preferably introduced into the base pile with its
ram head leading. The ram head has a contact portion, with which it
comes into contact with the driving pile to be supported
thereagainst. That is advantageous as the ramming pile is
stationary and does not yield after having been driven in, so that
it forms an advantageous support point for the aligning ram. The
aligning ram further has a support device which is adapted to come
into contact with the base pile. The base pile can be supported
against the aligning ram by means of the support device. For that
purpose the base pile preferably has a support portion which for
example can be in the form of a radially inwardly projecting
shoulder. After the ram head has come into contact with the driving
pile and the support device has been brought into engagement with
the base pile the aligning ram or at least a portion thereof is
extended in such a way that the base pile is displaced relative to
the driving pile upwardly with respect to a conventional
installation direction. Extension is preferably effected
hydraulically. For that purpose the aligning ram preferably has at
least one hydraulic cylinder, by means of which the base pile is
lifted or displaced relative to the driving pile. The hydraulic
cylinders can be for example in the form of part of the support
device so that the base pile is supported on the hydraulic
cylinders. As an alternative to the hydraulic cylinders it is also
possible to use screw spindles, toothed rack drives, cable
arrangements and the like.
[0029] Preferably the method further includes the step of:
introducing filling material through a passage in the aligning ram
into the driving pile and/or the overlap region between the driving
pile and the base pile. The aligning ram is arranged in the base
pile in the aligning procedure and the lifted base pile is
supported at the aligning ram which is supported on the driving
pile. For finally fixing the displaced positions of the base pile
and the driving pile relative to each other it is preferable for
filling material to be introduced at least into the intermediate
space between the driving pile and the base pile, preferably also
into the interior of the driving pile, and into a portion beneath
the overlap region and above the overlap region between the driving
pile and the base pile. Because the aligning ram has a passage
through which filling material can be introduced, it is
advantageously guided to the required locations. Additional tubes,
hoses and the like can be eliminated. That further simplifies
erection of the base structure.
[0030] In a further preferred embodiment of the invention it has
the step of: closing, preferably air-tightly sealing, the upper
open end of at least one base pile by means of a closure device.
Beforehand, preferably the aligning ram and further tools and
components disposed in the base pile are removed therefrom. Closing
the upper open end of the base pile and in particular air-tight
sealing thereof, prevents water and in particular oxygen-rich water
from being able to penetrate into the interior of the base pile and
prevents air exchange from occurring between a space inside the
base pile and a surrounding atmosphere. That therefore prevents
further oxygen being passed into the space inside the base pile,
whereby it is possible to prevent oxidation of the inside surface
of the base pile. That improves the service life of the base
structure. In addition further anti-corrosion measures can be
eliminated in that way. Such a closure device preferably has a head
cover for closing the upper end of the base pile and a sealing
material, for example concrete, for sealing off the head cover with
respect to the base pile.
[0031] The above-described method of erecting a base structure uses
an aligning ram which is preferably of the following configuration:
the aligning ram has a ram tube, a ram head connected to the ram
tube and a support device. The ram tube forms the passage for
feeding the filling material. The ram head has a contact surface
for coming into contact with the base pile. Preferably the ram head
has a centering projecting so that the ram head and thus the
aligning ram are fitted in centered relationship on the driving ram
even in the event of less accurate introduction of the aligning ram
into the base pile. The driving pile can be easily damaged at the
upper end by the pile driving operation. It is therefore
particularly advantageous for the ram head to have a centering
projection so that the ram head is placed in centered relationship
on the driving pile even in the case of a damaged driving pile. The
support device is preferably arranged at an upper end of the
aligning ram, preferably adjacent to the upper end of the base pile
at the ram tube or a ram body. The support device is preferably
arranged in height-adjustable or position-adjustable relationship
on the ram tube or a ram body. The support device preferably has
one or more hydraulic cylinders adapted to come into contact with a
support portion of the base pile in order to displace it relative
to the ram head, the ram tube and/or the driving pile. Hydraulic
cylinders are particularly preferred as high loads can be carried
thereby and exact displacement of the base pile relative to the
driving pile even by short distances is possible. Preferably the
aligning ram, in particular the ram tube and/or the ram head, has
guide surfaces and/or guide openings for guiding filling material.
Filling material can be introduced in specifically targeted fashion
into a gap between the driving pile and the base pile, into the
interior of the driving pile and/or into a portion above and below
the overlap region, by means of such guide surfaces and/or guide
openings. A base pile and therewith also a base structure can be
easily aligned and oriented by such an aligning ram. The aligning
ram is re-usable, it is employed only as a tool. It can also be
carried on a fitting ship and can be employed when required, that
is to say in the event of a base structure being set up in
inadequately oriented relationship. As the aligning ram is let down
from above the surface of the sea into the interior of the base
pile and operation is necessary only at the upper and of the
aligning ram, there is no need for complicated and expensive diver
interventions. That provides that erecting the base structure can
be effected substantially less expensively and faster.
[0032] Embodiments of the invention showing further inventive
features are illustrated in the drawing in which:
[0033] FIG. 1 shows a view of a base structure according to the
invention,
[0034] FIG. 2 shows a view of a portion of a base pile used for
anchorage in the seabed and the driving pile guided therein, in
section,
[0035] FIG. 3 shows a view of a base pile with a driving pile with
an aligning ram arranged in the interior of the base pile,
[0036] FIG. 4 shows a view of the upper end of a base pile in a
closed condition,
[0037] FIG. 5 shows a detail view of a portion from FIG. 4, and
[0038] FIG. 6 shows a fully sectioned overall view of a base
pile.
[0039] Reference 1 (FIG. 1) denotes a base or foundation structure
for an off-shore wind power installation, which has three
vertically extending base piles 2, 3 and 4 and a support structure
5 having a plurality of bars 6, 7, 8 and a central mounting 9 for
the pylon of a wind power installation (not shown). The base piles
2, 3, 4 stand on the seabed 10, driving piles 11, 12, 13 fixedly
connected thereto projecting out of same for anchorage in the
seabed. The base piles 2, 3, 4 are arranged parallel to each other.
To ensure secure anchoring the driving piles 11 through 13 have a
portion which is driven into the seabed and which approximately
corresponds to the depth of water at the installation location. The
support structure 5 connects at the same time the upper or free
ends of the base piles 2, 3, 4 together above the water line 14 so
that forces acting on the base structure 1 or the wind power
installation, due to wind and wave loads, are advantageously
distributed to all three base piles 2 through 4 and their driving
piles 11 through 13. In addition, provided at a predetermined depth
of water above the seabed 10 is a second support structure 15
having bars 16, 17, 18, which advantageously fixes the three base
piles 2 through 4 relative to each other during movement to the
installation location or during the pile driving operation. Both
the base piles 2 through 4 and the driving piles 11 through 13 and
also the posts or bars 6 through 8 of the support structure 5 are
preferably of a cylindrical configuration.
[0040] The central axis 9a of the central mounting 9 is exactly
vertically oriented. If after the base structure has been set up
the central axis 9a involves a deviation relative to the vertical,
which exceeds a predetermined deviation (for example 1 degree), it
is preferable for the base structure to be aligned by means of an
aligning ram 100 (see FIG. 3) as described hereinafter.
[0041] FIG. 2 shows a partial view of one of the base piles 2
through 4 with one of the driving piles 11 through 13 accommodated
therein in section and is intended in particular to more clearly
show the structure thereof. Each of the base piles 2 through 4 has
a wall of a plurality of layers 19, 20, 21 of different materials.
Introduced between the inner, preferably metallic layer 19 and the
outer metallic layer 20 is an intermediate layer 21 of a core
material such as for example concrete. In its foot region each base
pile 2 through 4 has a guide 22 for the driving pile, that reduces
its free cross-section at the inner peripheral surface, whereby the
driving piles are prevented from running out during the pile
driving operation. In that arrangement the guide is formed by means
of four plates 23, 23' which are arranged at the inner layer 19 of
a base pile and which extend at an angle of 90 degrees relative to
each other at the inside of the inner layer in the longitudinal
direction and extend radially inwardly. To provide a stable end
position for the driving piles 11 through 13 in a respective base
pile 2 through 4 provided at the outside of each driving pile at a
predetermined spacing beneath the upper end is an annular abutment
24 which comes to lie on the upper ends of the plates 23, 23' of
the guide 22 so that portions of the two piles provide relative to
each other an overlap region 25 of a predetermined length. The
abutment 24 can equally be omitted.
[0042] Provided at the underside of each base pile there is also a
bottom ring 26 having a seal for sealing off the guide gap relative
to the driving pile. That seal can also be omitted depending on the
respective use. It is not required for the invention. Each driving
pile 11 through 13 has a delimited driving pile head 27 delimited
by a bulkhead 28 which is arranged at a spacing from its upper end,
that approximately corresponds to double the length of the overlap
region 25, closing off the free internal cross-section thereof.
Both the driving pile head 27 above the bulkhead 28 and also the
gap 29 between the outside of the driving pile and the inside of
the base pile as well as the part of the base pile above the
overlap region 25 are filled with a hardening filling material 30.
To improve the tensile strength of the filling material 30, a
reinforcement 31 of for example bars is arranged at least
portion-wise on the inside of the driving pile wall. Each driving
pile 11 through 13 also has beneath the bulkhead 28 at least one
opening 32 in its pile wall for advantageous air venting during the
operation of driving the pile into the seabed 10.
[0043] FIG. 3 illustrates a base pile 2 set up on the seabed 10,
together with driven-in driving pile 11 and an aligning ram 100
which has been introduced into the base pile 2. Identical or
similar elements are denoted by the same references. In that
respect reference is directed in its entirety to the foregoing
description.
[0044] In this embodiment which substantially serves to illustrate
the aligning ram 100 the base pile 2 is in the form of a
single-layer, single-walled based pile. Preferably however it is in
the form of a multi-layer or sandwich pile, in accordance with the
foregoing description. At its lower end (with respect to FIG. 3)
the base pile 2 has a bottom ring 26 forming a support surface for
the base pile 2. In that case the bottom ring 26 forms a radial
enlargement of the base pile 2 so that it can sink less severely
into the seabed 10. The bottom ring 26 is supported in relation to
the base pile 2 by means of stiffening plates 34. In the case of a
multi-layer base pile the stiffening plates 34 can be fixed to the
outer layer, or also to the inner layer, and can extend outwardly
through a slot in the outer layer.
[0045] Guide plates 23 for guiding the driving pile 11 in the pile
driving operation are arranged at the lower end of the base pile 2,
directed radially inwardly. In addition later, when introducing
filling material 30, the guide plates 23 form a reinforcement for
making a better connection between the base pile and the filling
material 30 and thus also the driving pile. In addition arranged
both on the base pile 2 and also on the driving pile 11 are
reinforcing bars 33 which are also referred to as shear keys. In
this embodiment the driving pile 11 does not have any abutment for
abutting against the guide plates 23 as in that way the base pile 2
can be later displaced more easily relative to the driving pile 11
to align the base structure 1.
[0046] The aligning ram 100 has a ram tube 118, a ram head 106 and
a support device 105. At its lower end, with respect to FIG. 3, the
ram head 106 has a centering projection 117 for centeredly
contacting the ram head 106 by means of the contact surface 119
with the upper end of the driving pile 11. The centering projection
117 is of a substantially frustoconical shape. The aligning ram 100
can thus be used for different diameters of driving pile tubes.
Even if the upper and of the driving ram 11 is damaged, bent or
caused to stick out by the pile driving operation the ram head 106
can be brought into contact in centered relationship with the
driving pile 11. At its upper end the ram tube 118 has a filling
material inlet 112 arranged above the surface of the sea. Filling
material can be easily introduced into the interior of the driving
pile 11 from above the surface of the sea through the ram tube 118
which also forms a ram body. That can be clearly seen from FIG.
3.
[0047] The support device 105 is arranged on the ram tube 118 in
the proximity of the upper end of the base pile 2. In this
embodiment it comprises support portions 107 which are
height-adjustably fixed to the ram tube and hydraulic cylinders
having a lower part 108 and an upper part 109. The base pile 2 is
supported on the upper part 109 of the hydraulic cylinder. For that
purpose at the upper end the base pile 2 has an upper plate 111
which is releasably fixed thereto and which is arranged on the base
pile by means of a support ring 110. That upper plate 111, after
the aligning operation, can be removed together with the support
ring 110 from the base pile 2 and can be used again for aligning
another further base pile. The overall procedure for mounting the
support device 105, the support ring 110 and the upper plate 111 is
effected above the surface of the sea and therefore does not
require the use of divers. The hydraulic cylinder parts 108, 109 do
not come into contact with sea water and therefore do not have to
have any special corrosion protection.
[0048] The aligning operation can then take place as follows: an
aligning ram 100 is let down into two of the three base piles 2, 3,
4, the ram head 106 of the aligning ram resting exactly on the
upper end of the driving piles 11, 12, 13 by virtue of the conical
centering projection 117. Conical centering is effective even if
the head of the driving pile 11, 12, 13 should have been slightly
damaged by the pile driving operation.
[0049] The support device 105 is then assembled in the finished
condition so that the base pile 2, 3, 4 can be supported by means
thereof on the aligning ram 100. The hydraulic cylinders 108, 109
are extended by pressure actuation after fitment of all components.
The force produced by them acts on the aligning ram 100. The fact
of the ram head 106 being supported on the driven-in driving pile
11, 12, 13 provides that the base structure or base piles, together
with the support construction, is lifted at that location. The use
of two aligning rams 100 provides that the base structure whose
base piles correspond to the corners of a triangle is lifted at two
of the corner points and can thus be exactly vertically
aligned.
[0050] As soon as the desired position has been reached concrete 30
is introduced in a suitable amount through the ram tube 118 and
laterally thereof. The concrete 30 which is introduced through the
opening of the ram tube 118 will fix the driving pile 11, 12, 13 in
position after setting and will seal off the interior of the base
pile 2, 3, 4 to prevent the ingress of seabed which has possibly
been washed up, from the interior of the base pile 2, 3, 4.
[0051] The very highly fluid concrete which flows laterally along
the ram tube 118 slides off at the outside of the ram head 116 by
way of the inclined surface 120 and thus flows into the intended
position in the intermediate space between the base pile 2, 3, 4
and the driving pile 11, 12, 13. After the concrete has set the
aligning ram 100 and the upper plate 111 are removed together with
the support device 105.
[0052] After alignment of the base piles 2 and removal of the
aligning ram 100 from the base pile 2 and preferably also removal
of the upper plate 111 and the support ring 110, it is advantageous
to close the upper end of the base pile 2. A closure device 150 is
illustrated in FIGS. 4 and 5. Accordingly the closure device 150
substantially has a head cover 150 which is of a substantially
plate-shaped configuration and is of a radius which very
substantially corresponds to or is somewhat larger than the radius
of the base pile 2. As can be seen from the detail view in FIG. 5 a
seal holding ring 55 is arranged for the sealing device 150 in
outward relationship at the upper end of the base pile 2, forming
an annular passage for sealing material 54. Arranged on the head
cover 50 is an annular axial projection 56 which engages into the
annular passage of the seal holding ring 55. The seal holding ring
55 is filled around the projection 56 with sealing material 54
which closes off the space inside the base pile 2 with respect to
the environment. In addition the head cover 50 is screwed to the
base pile 2 by means of screws 53. The screws 53 are also sealed
off with sealing material 54 which is supported by a second seal
holding ring 55. Sealing rings 51 are further arranged between the
head cover 50 and the base pile 2 for additional safeguard
purposes. That therefore affords air-tight closure of the space
inside the base pile 2 with respect to the environment, which can
outlast the entire service life of the base structure and which
permanently closes off the space inside the base pile 2 in relation
to exchange of air with the environment.
[0053] FIG. 6 shows a full section of a base pile 402. Identical or
similar reference numerals are denoted by reference numerals
increased by 400, in that respect reference is directed in its
entirety to the foregoing description. The base pile 402 is in the
form of a sandwich pile and has an inner tube forming the inner
layer 419 and an outer tube forming the outer layer 420. A
respective sandwich connection 450a, 450b is arranged at each of
the axial ends of the inner and outer tubes 419, 420 respectively.
The sandwich connection 450a, 450b has a ring flange 452a, 452b
which is shaped conically in cross-section and which connects the
inner and outer tubes 419, 420 together. On the other side the ring
flange 452a, 452b is connected with a tube connection 451a, 451b
which is in the form of a solid tube. Arranged in the intermediate
space between the tubes 419, 420 are reinforcing bars 433 which
extend along the longitudinal axis and which extend through
openings in the ring flanges 452a, 452b. Those reinforcing bars 433
are also connected to the connecting tubes 451a, 451b.
[0054] The base pile 402 is placed on the seabed 10. Arranged in
the interior of the base pile 402 is a driving pile 411 which has a
bulkhead 428 in the proximity of its head end, and two air vent
openings 432 arranged under the bulkhead 428. The upper region of
the driving pile 411 is filled with concrete 430a. Preferably the
concrete 430a is introduced to a height which approximately
corresponds to twice the diameter of the driving pile 411. Concrete
430b is also introduced in the intermediate space between the
driving pile 411 and the base pile 402 in order to form a fixed
solid connection between the two piles 402, 411.
* * * * *