METHOD FOR PREPARATION AND ERECTION OF A TUBULAR TOWER STRUCTURE
This invention relates to a method for the erection of tubular tower constructions.
Tubular tower constructions are known, more particularly as support structures of wind energy installations.
In this connection it is known more particularly to fabricate tube sections from steel plate and to put together the tube sections one on top of the other with circumferential weld seams to form a tubular tower, which accommodates a wind energy gondola at its upper end.
In order to connect the individual segments together, it is known either to weld them or provide them with circumferential flanges lying on top of each other, such that the flanges lying on top of each other can be bolted together.
Beyond that it is known to form such tower constructions from partial shells, whereby the partial shells have flanges on their longitudinal edges, with which these partial shells are bolted together.
Known from WO 2011/092235 A2 is a wind power plant tower segment, which is also formed as a jacket segment and comprises a reinforced concrete body, comprising two faces for attaching to faces of at least one further tower segment and in the region of each face at least one connecting body is introduced in the reinforced concrete body and anchored therein for connecting to a connecting body of an adjoining tower segment and the connecting body comprises a fastening wall that is disposed substantially parallel to the respective face for absorbing a tensile load that is directed transversely to the face and transversely to the fastening wall.
A disadvantage of such a device is that it is relatively complicated to cast such concrete shells and moreover to manufacture them with fitting precision and dimensional accuracy.
Furthermore the dismantling of such reinforced concrete towers is very complicated and expensive.
Known from DE 10 2010 039 796 Al is a tower with an adapter piece and also a method for manufacturing a tower with the adapter piece, whereby here likewise a lower tubular tower section is made of concrete and an upper tubular tower section is made of steel.
Such hybrid towers are currently preferred for the erection of especially high wind energy installation towers, because large diameters are possible with the concrete substructure and in this way conventional wind energy installation towers can be placed on top of the substructure towers, in order to achieve greater heights and thus a better wind yield.
However, a disadvantage here is that the dismantling of a concrete tower is relatively complicated and the assembly cost for concrete towers is relatively high, more particularly owing to the delivery of concrete.
Known from WO 2010/121630 A2 is a tower for a wind power plant having a plurality of corner bars for forming a mast construction, wherein the corner bars are each made up of a plurality of partial profiles connected to each other.
Here the corner bars are each made up of a plurality of partial profiles connected to each other, such that connection areas are formed on adjacent partial profiles, which are however bent out from the partial profiles.
A disadvantage of this embodiment is that it makes precise and quick work difficult.
Known likewise from DE 10 2009 058 124 B4 is a concrete substructure for the tower of a wind energy installation.
Known from DE 10 2011 603 Al is a load handling device for lifting heavy components or parts of installations, more particularly offshore installations.
Known from DE 203 21 897 U1 is a wind turbine comprising a stationary vertical mast or tower on which the moving part of the wind turbine is arranged, which mast is at least partly composed from prefabricated wall parts, with several adjacent wall parts forming a substantially annular mast part.
Here the wall parts or segments are made up of reinforced concrete or another stone-like material and already prefabricated.
The concrete elements are fastened to each other with initial tension.
Known from DE 10 2011 001 250 Al are a device and method for the transition between a steel tower section and a prestressed concrete tower section.
Known from DE 10 2011 077 428 Al is a wind energy installation tower with a plurality of prefabricated tower segments each having an upper and lower horizontal flange, whereby one of the plurality of tower segments has at least two longitudinal flanges, whereby each longitudinal flange has a first side for application to a first side of a further longitudinal flange and a second side which is welded on the jacket surface at the side, whereby the second side lies opposite the first side.
Known from DE 11 2010 005 382 T5 is a wall portion for a wind turbine tower, the wall portion comprising a first wall segment and a second wall segment and also a connection member comprising a first surface portion mounted on the first wall segment and extending in a first direction, a second surface portion mounted on the second wall segment and extending in a second direction, and an intermediate portion comprising an intermediate surface portion extending transverse to the first direction and transverse to the second direction, whereby the connecting element is thereby formed in a T-shape and is placed onto a corresponding wall and two walls abutting each other and is connected thereto with bolts, which pass through the wall.
Known from DE 203 21 855 U1 is a tubular tower construction, which is formed from tubular tower construction shells, whereby the tubular tower construction shells are produced individually and after production of the tubular tower construction shells flanges are welded on the longitudinal edges of these shells.
The construction is then put together from the shells and bolted on the flanges.
It is the object of the invention to create a method with which such tower constructions can be erected mare quickly and with greater precision and fitting precision.
The object is achieved with a method having the method steps of claim 1. Advantageous further developments are characterised in the subordinate claims dependent hereon.
A tower construction erected according to the invention serves more particularly as substructure tower, so a conventional tower to accommodate wind energy installations can be placed upon it and thereby a greater height and thus better access to wind can be achieved.
For greater heights of such tower constructions it is necessary to enlarge the tower cross-section, because only then can the required structural stability and safety against buckling be achieved.
Usually such towers are made of tower segments with a circular cross-section, placed on top of each other and connected together.
Owing to the usual bridge height in Germany very large tower cross-sections can no longer be produced from one-piece tube sections or tube segments.
As a result of this, in order to comply with the vertical clearance, it is necessary to assemble together such very wide towers with a diameter of more than 4.5 m at the base from partial shells, i.e. annular segments, to form a complete ring and — as necessary — to place a plurality of these rings one on top of the other.
Basically it is known, to make such longitudinally orientated shells and to put these shells together at the installation site to form a tube.
It has emerged however that the precision and the tolerances are so great that assembly is very often delayed and made unnecessarily difficult.
According to the invention the tubular tower construction is first manufactured in its entirety at the manufacturing site and erected, such that the tubular tower construction is erected in partial lengths that are still transportable or, if the length is still transportable, in its full length. To this end appropriate sheets and bars are fabricated from steel plate and these are then rolled, such that they abut each other with a longitudinal edge and form an annular segment or a tube segment. This tube segment is then welded on this joint edge. Further tube segments are placed on top of this and likewise welded, until a complete tubular tower construction is formed. Then, into this tubular tower construction, according to a desired number of partial shells, flanges extending axially are welded from outside onto the tower construction wall or from inside onto the tower construction wall, whereby two flanges lying side by side always form a flange pair and are welded on. Thus, in the case of a tubular tower construction consisting of four partial shells, eight flanges in total are welded on outside or inside in four pairs. Then the tube is separated between the respective flange pairs into the corresponding partial shells. The partial shells are then transported to the construction site and there they are put together again accordingly to form a tubular tower construction and are connected together by means of the flanges. In the invention it is of advantage that the flanges and the welding of the flanges to the tubular tower construction wall is extraordinarily precise and verifiably accurate. In addition the flanges on the entire tubular tower construction can be aligned and fastened in an especially good way, in order to bring about a weld. Furthermore it is of advantage that these welds and the subsequent separation of the tubular tower construction into the shell elements takes place under verifiable conditions at the manufacturing site, whereby a corresponding review can take place at the manufacturing site. At the place of use the entire tower needs only to be put together and bolted together from, for example, four shells. In addition it has emerged that, with the method according to the invention, according to which the flanges are welded onto the wall from inside or outside, a greater stability results than with flanges that are welded onto the abutting surface. The invention is explained by way of example with the help of a drawing. The figures show the following:
Fig. 1a: an annular tube with a longitudinal weld seam as starting construction;
Fig. 1b: the tube according to Fig. 1a with schematically represented welded-on flanges;
Fig. 1c: the situation after separation into two tower construction shells between the flange pairs;
Fig. 2: a tubular tower construction with internal flanges that are connected together; 5 Fig. 3: a tubular tower construction with external flanges that are connected together;
Fig. 4: a tubular tower construction comprising a plurality of tube sections, whereby the lines of separation and flanges are aligned;
Fig. 5: a tubular tower construction comprising a plurality of tube sections with lines of separation and flanges that are offset in relation to each other;
Fig. 6a: a section from a tubular tower construction wall;
Fig. 6b: the wall according to Fig. 6a with a first placed and welded flange;
Fig. 6c: the wall with a second placed flange welded along an abutting edge;
Fig. 6d: the line of separation in the wall of the tubular tower construction between the two flanges;
Fig. 6e: the tubular tower construction, separated between the flanges, with a second fillet weld, placed onto the second flange, along the abutting edge;
Fig. 7a-f: the connection of the flanges as full connection;
Fig. 8a-d flanges with lining plates;
Fig. 9: the tubular tower construction in a view from outside comprising a plurality of tube segments that are welded together;
Fig. 10: the base of the tubular tower construction with a double annular flange to the inside and to the outside for fastening to a foundation;
Fig. 11: the annular flange with the tubular tower construction wall and a part of a longitudinally extending flange in a partially cut-away view;
Fig. 12: the head region of the tubular tower construction with an internal circular flange for fastening further tube elements;
Fig. 13: the head region of the tubular tower construction in a partially cut-away view;
Fig. 14: the view from inside onto a tubular tower construction shell with a longitudinally extending flange on each of the longitudinal edges;
Fig. 15: the tubular tower construction shell according to Fig. 10 in a partially cut- away top plan view onto the base region with an annular flange on the inside and outside;
Fig. 16: the head region of the tubular tower construction shell with a flange on the inside. For the manufacture and erection of a tubular tower construction steel plate of a desired width, length and thickness is bent such that it forms a circular tube or a circular tube section. In the case of very large diameters individual tube section segments can be welded together with a plurality of longitudinal weld seams to form a tube section (Fig.
1a). Such a tube section 1 is formed with an annular cross-section and has on at least two axial edges 2 that are facing each other an axial weld seam 3 connecting them. In this way a round tube wall 4 is formed, having in each case a radial circumferential abutting face
5. The axial length of the tube section 1 is limited substantially by the width of the bent steel plate and the bending devices available. The tube sections 1 are more particularly of tapered shape, so the diameter at one axial end is larger than at the opposite axial end. In this way tapered towers (Fig. 9) can be achieved from a plurality of such tapered tube sections 1. In this connection the individual tube sections 1 have, for example, a height of 1.5 to 3 m, whereby a tube section 1 has a diameter of, for example, 7 m at the base of a tubular tower construction 6 {Fig. 9) and a diameter of 4.5 m in the region of the head. For the erection of the tubular tower construction 6 the tapered tube sections 1 are placed one on top of the other and welded circumferentially in the region of their circumferential edges 5. The method according to the invention provides for one or more tube sections 1 welded together axially to be combined to a transportable length, whereby, if suitable transport equipment is used, even a complete tubular tower construction 6 can be put together accordingly from tube sections 1. In order to manufacture, transport and erect such a tubular tower construction 6, it is necessary to separate such a tubular tower construction 6 longitudinally into tubular tower construction shell lengths 6a, otherwise transport by road cannot be ensured. For this the tubular tower construction 6 or a plurality of axially consecutive tube sections 1 is first equipped with a pair of longitudinally extending flanges 7, 8 in the region of desired separation lines 20. The flanges 7, 8 can be arranged both externally (Fig. 3) and also internally (Fig. 2) along planned lines of separation on the tube wall 4.
In the simplest case a tubular tower construction 6 or a tube section 1 has two lines of separation 20, such that it is separable into two half-shells 1a, whereby a flange 7 and a flange 8, respectively, remain along an axial edge 11 formed by the separation.
For assembly of the flanges 7, 8 the flanges 7, 8 can be connected together; this connection can be a bolted connection through the existing bolt holes 11 (Fig. 11), a riveted connection or tacking with weld spots or short weld seams.
For this the flanges can be formed with wide sides 12 lying adjacent to one another; however, lining plates or other spacers 13 can also be present between the flanges 7, 8 (Fig. 8a to 8d). In this way a good axial orientation and alignment of the flanges is ensured.
In a first possible implementation of the arrangement of the flanges 7, 8 on the inner surface 14 of a wall 4 of a tubular tower construction 6 or of a tube section 1 a first flange 7, which is rectangular in cross-section and therefore has two narrow sides 15, 16 running parallel to each other and two parallel wide sides 12, is positioned and fixed with one narrow side 15 on the inner surface 14 of the wall 4. This flange is then welded, for example, with fillet seams 17 to the surface 14. Here the fillet seams can fill the angle between the surfaces 12 and 14. To accommodate the seams, however, appropriate bevels may also be present in the region between the walls or surfaces 12 and the abutting face 15 of the flange, so the seams 17 do not protrude.
Then the second flange 8 is positioned parallel to the first flange 7 on the surface 14 and welded with at least one fillet seam 18 to the surface 14. In this case the wide surface 12 of the flange 8 opposite the fillet seam 18 cannot be reached or is difficult to reach for welding.
In order now to fabricate the corresponding half-shells 1a from the tube section 1, a separation 20 is performed along a desired line of separation running between the flanges 7, 8 and then the two shells 1a are separated from each other, such that the previously unwelded region of the flange 8 is accessible and can be connected likewise to the surface 14 with a seam.
The edges 21 of the partial shells 1a resulting from the separation and also the surfaces 12 of the flanges 7, 8 that face each other can be radially aligned.
The flanges 7, 8 can however also be arranged set back a slight distance from the edges 21 on the surface 14. In a further advantageous embodiment the flanges 7, 8 are fastened to the surface 14 with what is known as a full connection (Fig. 7a to 7f). Here the flanges for fastening can already be connected together, more particularly by way of bolt holes 11 and with their surfaces 12 adjacent to each other (Fig. 7a), although the flanges can also be arranged individually.
In order to guarantee the full connection, the flanges 7, 8 have bevelled abutting faces 15, such that they lie with only a very narrow region on the surface 14 and a notch results between the flanges 7, 8 and the surface 14, whereby in respect of adjacently arranged flanges 7, 8 these notches are formed pointing diametrically away from each other. After positioning and fixing of the flanges on the surfaces 14 these notches can each be filled with weld seams 18, so full connection is guaranteed. Then separation 20, abrasive separation or thermal separation 20 takes place, so edges 21 of the partial shells 1a are again formed and one flange 7 remains on the one-part shell 1a and the other flange 8 remains on the other partial shell 1a. Particularly in the region in which the two surfaces 12 of the flanges abut each other, or in the region of the notch base 22, during welding with full connection a weld seam root 23 can form, which ultimately also connects together the two flanges 7, 8 (Fig.
7e). This weld seam root 23 has to be removed, in order to separate the two partial shells 1a from each other. This is achieved usefully by means of separation (Fig. 7f), whereby the separation is performed through the wall 4 of the tube section 1, until the weld seam root 23 is also removed, whereupon the partial shells 1a and thus also the flanges 7, 8 can be separated from each other. In order to close the resulting gap, which would appear again even if the flanges were bolted together, an appropriate lining plate or a seal can be inserted during assembly {between the face edges 21). Such lining plates or seals are arranged between the flanges 7, 8 and the edges 21 of the half-shells, in order to cancel out tolerances or produce a seal between the edges 21 andthe flanges 7, 8. In this connection the lining plates can be located (Fig. 8c) between the flanges 7, 8 and between the edges 21 and extend outwards from the flanges 7, 8 through the wall 4 of the partial shells 1a. If in the assembled state the edges 21 abut each other tightly (Fig. 8d), lining plates can be present between the flanges 7, 8 set back in relation to the edges 21. Beyond that H or double-T sealing elements 24 can be arranged between the edges 21, whereby these can also be formed as a single piece with the lining plates 13. Thus, in the erected state, a corresponding tubular tower construction 6 (Fig. 9) has a plurality of lines of separation 20, with which the partial shells 1a consisting of the appropriately connected segments of the tube sections 1 are joined together. To connect such a tubular tower construction 6 with further tubular tower constructions or a usual tubular tower for accommodating a wind energy installation, the tubular tower construction has an annular flange 24 on its abutting face 23 with the smaller diameter.
The annular flange 24 consists preferably of annular flange segments 24a, which are welded finally into the partial shells 1a at one end.
Such an annular flange 24 can be provided both on a narrower end of the tubular tower construction 6 and also on a wider end of the tubular tower construction 6, more particularly if the tubular tower construction 6 is part of a larger tubular tower construction {not shown) and is arranged between a wider part below it and a narrower part above it.
Such an annular flange (Fig. 13) is substantially annular in shape with an inner circumferential surface 27, an outer circumferential surface 28, an abutting face 26 and an abutting face 29 running parallel to this.
In extension of an outer circumferential wall 28 beyond the abutting face 29 there is a connection ring 30 on the flange 24, which has a thickness relative to the radial extension which equates approximately to the thickness of a wall of a tubular tower construction and is welded onto the wall with this ring.
If the tubular tower construction 6 is used as intermediate part in a larger tubular tower construction, such a flange 24 is also arranged on the wall in the region of the largest diameter of the tubular tower construction.
In one embodiment, in which the tubular tower construction 6 is fastened to a foundation, an annular flange 31 is provided in the region of the greatest width, i.e. on the ground side of the wall of the tubular tower construction 6. The flange ring 31 is in the form of a double-ring with two concentrically running rows of holes 32, 33, whereby the rows of holes 32, 33 are arranged extending axially in relation to the longitudinal extension of a tubular tower construction.
In this way the flange ring 31 forms a flat support surface 34, a surface 35 running parallel to this and also an inner circumferential abutting face 36 and an outer circumferential abutting face 37. Between the abutting faces 36, 37, approximately in the radial centre of the surface 35, an annular web 38 projects from the surface 35, whereby the annular web 38 has a free, circumferential radial edge 39. The annular web 38 has a thickness that corresponds to the thickness of the wall 4 of a tubular tower construction.
The annular web 38 can be welded onto a corresponding edge 40 of the tubular tower construction wall 4 with the edge 39.
A partial shell 6a of a corresponding tubular tower construction 6 (Fig. 14) is in cross-section a circular ring segment (Fig. 15 partially cut away), which usually tapers, such that the circular ring segment narrows from a lower region (Fig. 15) to an upper region (Fig. 16). The tubular tower construction segment 6a has respectively a flange 7 and a flange 8 on axial edges in the already described manner, to connect a plurality of segments, whereby the flanges 7, 8 correspondingly have rows of holes, through which the flanges 7, 8 can be connected together.
The connection can be made basically with bolts, rivets and welds.
So-called locking ring bolts, which are ultimately bolts placed on threaded press sleeves and require little or no maintenance, have proven to be favourable.
A tubular tower construction segment manufactured in that form or a tubular tower construction shell 6a manufactured in that way has the already addressed flanges 24, 31 at the upper and lower ends.
The shells 6a are thus formed from a plurality of partial shells 1a or tube sections 1a, whereby the tube sections 1a are in each case placed on top of each other with joint edges 5 and are welded together.
In order to stabilise and,
if appropriate, to arrange components within a tower, annular frames 40 or annular frame segments 40 can be welded in approximately in the axial centre between two joint edges 5 abutting each other.
In addition a longitudinal frame 41, extending over the entire length or a partial length of the partial shell 6a, can be welded in in the radial centre between the two flanges 7, 8.
In the invention it is of advantage that a tubular tower construction 6 consisting of tube sections 1a, 6a, which more particularly are tapered, is manufactured completely in an appropriate fabrication facility.
Under predetermined conditions, which allow the smallest tolerances, flanges extending longitudinally or axially are welded onto the inside or outside of the tube wall 4 and then the tubular tower construction is separated between the flanges into at least two partial shells 6a, preferably more partial shells 6a, more particularly four to fourteen partial shells 6a, which can be transported well, even on roads.
At an erection site of the tubular tower construction the partial shells are reconnected together, this happening in an especially easy manner, because the partial shells are matched to fit absolutely exactly.
In contrast to conventional erection concepts, in which such a tubular tower is put together from individual lengths of tube or tube sections and welded, the assembly of such a tubular tower construction can happen in a fraction of the assembly time, whereby additionally a tubular tower construction with very large diameters, more particularly diameters at the base < 7 m, can be achieved.
More particularly it is of advantage that, with such a tubular tower construction, avery high substructure for known tubular towers that carry wind energy installations can be made in a manner allowing simple, cost-effective and rapid assembly, such that usual wind energy installations can be brought higher into the wind and thus their effectiveness can be increased.