Patent Application
20130219821
The present invention relates to a method of assembling a tubular building structure and in particular to a method of assembling a tubular building structure comprising a circumferential wall structure formed from a plurality of wall elements.
Tubular building structures are used in a number of applications, such as for telecommunication towers, amusement towers and wind turbine towers. In such towers having a substantially closed outer surface, the structures are often made from tube sections of rolled steel plate arranged on top of each other. For large diameter structures, each tube section may be formed by interconnected axially extending tube segments, whereby they are easier to transport from the manufacturing site to the erection site. Such tube segments are typically made from rolled or bent steel plate. The tube sections can be joined by welding, but this may cause weaknesses e.g. due to induction of thermal stresses and therefore require highly skilled people and appropriate quality control. Alternatively, the tube sections can be joined by using traditional bolts and nuts, but this method also has some disadvantages. The plates are typically surface treated at the manufacturing site, but moisture percolating into the screw connections over time often results in corrosion which may be undesired for aesthetic reasons and which potentially leads to structural weaknesses.
Another disadvantage of assembling closed structures by traditional bolt-and-nut connections is that it requires access to both sides of the structure being assembled at the same time. This is particularly problematic when assembling so tall building structures that the people performing the assembly cannot stand on the ground.
Hence, an improved method of assembling a tubular building structure would be advantageous, and in particular a more efficient and/or reliable method would be advantageous.
It is an object of the present invention to provide a method of assembling a tubular building structure by which method the corrosion resistance of the joining points can be improved compared to known methods.
It is a further object of the present invention to provide a method of assembling a tubular building structure by which the assembly can be performed from one side of the tubular building structure, such as from the inside.
It is a further object of the present invention to provide an alternative to the prior art.
Thus, the above described objects and several other objects are intended to be obtained in an aspect of the invention by providing a method of assembling a tubular building structure comprising a circumferential wall structure formed from a plurality of wall elements, the method comprising the step of mutually assembling at least some of the wall elements by use of screw sockets mounted in holes in the wall elements and bolts.
The wall elements may be made from plate material, such as from steel plates. The plates may e.g. be shaped by rolling or by bending.
In some embodiments of the invention, at least some of the wall elements are superposed tube sections, and the method comprises the step of arranging the tube sections on top of each other.
At least some of the wall elements may be axially extending tube segments, and preferably they are interconnected to form the tube sections. “Wall element” is thus used in relation both to tube sections and tube segments. A method according to the present invention may then comprise the step of interconnecting the tube segments along opposite longitudinal sides by use of screw sockets mounted in holes in the tube segments and bolts.
Such tube segments may have inwardly extending flanges along opposite edges so that the tube sections are formed by assembling the tube segments along these flanges. Such assembly may be done by traditional bolt-and-nut connections or by use of screw sockets and bolts.
The screw sockets may be mounted in the wall elements at the manufacturing site, and the wall elements may subsequently be transported to the erection site of the tubular building structure. Hereby it becomes possible to perform a surface treatment of the wall elements with the screw sockets mounted therein at the manufacturing site.
By “manufacturing site” is preferably meant the same location as where the wall elements are manufactured, e.g. by rolling or bending of steel plates. However, the present invention also covers a method in which the screw sockets are mounted in the wall elements at a different manufacturing site. This can e.g. be relevant for a company erecting the tubular building structure after having bought the wall elements and the screw sockets from two different suppliers.
A possible method may comprise the following steps:
The first and second surface treatments are preferably done at the same manufacturing site, but it is also covered by the present invention to have the two surface treatments done at different locations, such as by sub-contractors specialized in different treatment methods. By “exterior” is preferably meant the side forming the outer surface of the tubular building structure after erection.
In a method comprising these steps, the first surface treatment may be selected from one or more of the following processes: galvanizing, such as hot dip galvanizing, powder coating and wet paint system. Other appropriate surface treatments may also be used; such processes will be well-known to a person skilled in the art. The second surface treatment may comprise application of a coating, such as lacquer, powder coating and/or wet paint system. Hereby a sealed outer surface can be obtained whereby the risk of moisture percolating into the connections over time and the resulting likely corrosion can be minimised compared to traditional assembly methods by use of ordinary bolt-and-nut connections. Further surface treatments may be performed if desired.
At least some of the screw sockets may each comprise a serrated circumferential surface adapted to provide frictional resistance against rotation of the screw socket after mounting. Alternatively the mating surfaces may be un-serrated. Both for serrated and un-serrated surfaces the screw sockets may be fastened by press fit, magnets and/or adhesive.
In preferred embodiments of the invention, the mutual assembly of the wall elements is performable solely by people working inside the tubular building structure fastening the bolts to the mounted screw sockets. The people can e.g.
stand on platforms arranged inside the tubular building structure. Hereby the people are better protected from bad weather conditions, such as heavy wind. Furthermore, for tall building structures it can be avoided to use cranes to lift people to the necessary height on the outside where it would be inconvenient or impossible to use platforms.
For alternative embodiments, the mutual assembly of the wall elements is performable solely by people working outside the tubular building structure fastening the bolts to the mounted screw sockets; this being obtained by changing the orientation of the screw sockets. This possibility is particularly relevant for building structures being so narrow that is would be impossible or inconvenient to have people working inside the structure.
In an embodiment of the present invention, the tubular building structure is a wind turbine tower comprising a bedframe, and the method may further comprise the step of mounting the bedframe by use of screw sockets and bolts. Hereby it will be easier to perform the mounting when there is only limited space for people and for the tools used during the assembling process. The above advantages mentioned in relation to surface treatment of the tube sections and the tube segments also apply for the area of the bedframe.
A method as described above may be used for assembly of any tubular building structure where it is desired to reach one or more of the objects of the present invention. Such a tubular building structure may e.g. be a wind turbine tower.
The method of assembling a tubular building structure according to the invention will now be described in more detail with regard to the accompanying figures. The figures show one way of implementing the present invention and is not to be construed as being limiting to other possible embodiments falling within the scope of the attached claim set.
Tubular building structures 1 are used in a number of applications including towers for telecommunication and for wind turbines. They are often made from superposed tube sections 2 which are arranged on top of each other by use of a crane and assembled by welding or by use of traditional bolt-and-nut connections.
The tube sections 2 may e.g. be made from plate material, such as from rolled or bent steel plate. Each tube section 2 may also be formed by interconnecting axially extending tube segments 20 as shown schematically for the two lower tube sections 2 in
The tubular building structure 1 in
A method of assembling a tubular building structure 1 according to the present invention comprises the use of screw sockets 4 and bolts 5 (see
The screw socket 4 is e.g. pressed into the hole in the plate 7 by any suitable method which will be well-known to a person skilled in the art. The circumferential surface 8 of the screw socket 4 which engages with the hole in the plate 7 is serrated in the embodiment shown in
In a preferred embodiment of the invention, the screw sockets 4 are mounted in holes in the tube sections 2 at the manufacturing site, and the tube sections 2 are subsequently transported to the erection site of the tubular building structure 1. The assembly is then performed by screwing bolts 5 into the screw sockets 4. The use of pre-mounted screw sockets 4 means that this can be performed solely by people working inside the tubular building structure, e.g. while standing on permanent or temporary platforms. Hereby the assembly process is made easier compared to methods requiring people working from both the inside and the outside of the tubular building structure. Furthermore, the workers are hereby protected from e.g. strong winds.
The manufacturing typically comprises surface treatment which e.g. comprises the following steps:
Hereby it is possible to obtain a sealed outer surface whereby the risk of moisture percolation and resulting corrosion is minimised compared to assembly methods based on traditional bolt-and-nut connections.
The first surface treatment may e.g. comprise galvanizing, such as hot dip galvanizing, powder coating and wet paint system. The second surface treatment may comprise application of a coating, such as lacquer and/or paint.
Although the present invention has been described in connection with the specified embodiments, it should not be construed as being in any way limited to the presented examples. The scope of the present invention is set out by the accompanying claim set. In the context of the claims, the terms “comprising” or “comprises” do not exclude other possible elements or steps. Also, the mentioning of references such as “a” or “an” etc. should not be construed as excluding a plurality. The use of reference signs in the claims with respect to elements indicated in the figures shall also not be construed as limiting the scope of the invention. Furthermore, individual features mentioned in different claims, may possibly be advantageously combined, and the mentioning of these features in different claims does not exclude that a combination of features is not possible and advantageous.
| Number | Date | Country | Kind |
|---|---|---|---|
| PA 2010 70330 | Jul 2010 | DK | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/DK2011/050262 | 7/4/2011 | WO | 00 | 5/9/2013 |
