EP1690999A2

EP1690999A2 - Steel beam

Info

Publication number: EP1690999A2
Application number: EP06101095A
Authority: EP
Inventors: Juhani Mäki-Fossi; Mari Mäki-Fossi
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-02-10
Filing date: 2006-01-31
Publication date: 2006-08-16
Also published as: FIU20050045U0; FI6681U1; EP1690999A3

Abstract

The invention relates to a steel beam used in the structures of buildings, provided with a steel cover plate, a bottom plate and a web plate. The invention also relates to a method for manufacturing and using this kind of a steel beam. In a steel beam (1) according to the invention, the top edge (4y, 5y) of the web plate (4, 5) is attached to the cover plate (2), so that the top edge (4y, 5y) of the web plate is located at a distance (6) from the cover plate edge (2r).

Description

Background of the art

The invention relates to a steel beam used in the structures of buildings and provided with a steel cover plate, a bottom plate and a web plate. The invention also relates to a method for manufacturing and using a steel beam of this type.
Steel beam structures are used in the structures of buildings, such as in the housing of a building as bearing structures in intermediate floors or roofs, for example as centre and edge beams and as booms in lattice structures. In case of fire, the steel structures must endure extremely demanding conditions. This sets very high requirements for the steel structures of the beam.
Often the assembling of the steel elements also is complicated and slow, because during the assembly, they must often be supported by special arrangements. Often the assembling also is slow, because the beams include many elements that must be welded together. As examples of known steel beams, let us point out the steel beam introduced in the Finnish patent application 930696, where the steel beam is compiled of two symmetrical elements that are interconnected.

General description of the invention

We have now invented a steel beam to be used in the structures of buildings that is particularly bearing even in demanding conditions. In order to achieve this aim, the invention is characterized by features that are set forth in the independent claims. Other claims enlist preferred embodiments of the invention.
The steel beam according to the invention to be used in the structures of buildings has a steel cover plate, a bottom plate and a web plate, and the top edge of the web plate is fastened to the cover plate, so that the top edge of the web plate is placed at a distance from the cover plate edge, in which case the outer edge of the cover plate forms an edge structure.
The cover plate of a beam according to the invention can be freely varied. Depending on the target of usage, it may be for example 100-600 mm, such as preferably 150-500 mm. Likewise, the height of the web plate may be freely varied, and it can be for example 100-600 mm, such as preferably 150-500 mm.
In these preferred embodiments, also manufacturing is economical, because they are easy to make and handle. The width of the bottom plate is determined by the angles between the plates.
Advantageously the top edge of the web plate is placed at a distance of 10-50 mm from the cover plate edge. When the beam is bent during usage, a structure of the building, such as a surface slab, slides on top of the cover plate of the steel beam in the lengthwise direction of the beam. This sliding is prevented by the edge structure, and thus the structure and the steel beam are made to cooperate, and at the same time the bending resistance/load resistance of the whole system is improved. An edge structure of 10-50 mm constitutes an adequate projection with a sufficient surface area in order to make for instance the cooperation between the cover plate and for example the surface slab to be optimal. If the edge recesses were even deeper, the transversal surface of the cover plate would become too small at the recess, and the capacity would be reduced.
A beam according to the invention is particularly well attached to concrete structures. In addition, this kind of beam is technically economical and simple to manufacture. In case of fire, the edges of the cover plate take a grip of the concrete structures, in which case the beam has a relatively longer resistance than a beam without said edge structures.
In the following description, the term concrete means all kinds of concrete, such as high-strength concrete, fiber concrete, reinforced concrete or light-weight concrete.
With a steel beam according to the invention, the cooperation between the beam and another element to be connected thereto, said element representing internal concrete, a surface slab and/or a slab system, is virtually optimal. This enables particularly low, light, rigid and durable structures in normal usage situations, and a particularly good joint structure in case of fire.
According to an embodiment of the invention, the cover plate edge is provided with one or more edge recesses. Respectively, edge projections are formed in the cover plate. These have an essential affect on the fastening of the beam for example to concrete, and thus the structure and the steel beam are made to cooperate well, and the bending resistance/load resistance of the system is improved. This is essentially advantageous for instance in case of fire. In addition, the edge recesses are advantageous when casting concrete, because they in part serve as air gaps.
According to an embodiment of the invention, the cover plate edge is provided with one or more edge recesses, and the top edge of the web plate is provided with one or more web projections that can be fitted in the edge recesses of the cover plate edge for fastening the cover plate and the web plate together. This solution is advantageous when compiling the beam, because in that case the projections serve as support elements.
According to an embodiment of the invention, both edges of the cover plate are provided with edge recesses that are with respect to each other placed at an identical location in relation to the cover plate lengthwise axis. In certain applications this arrangement is particularly advantageous, because the manufacturing process can be simplified and rationalized. For example in composite beams, the edge recesses improve the fastening of the concrete in the top parts of the beam, which is essentially advantageous for instance in the case of fire.
According to an embodiment of the invention, both edges of the cover plate are provided with edge recesses that with respect to each other are at least partly placed in different locations in relation to the cover plate lengthwise axis. This arrangement is advantageous for instance when aiming at a more even load and fastening to the concrete.
According to an embodiment of the invention, the sectional plane of the cover plate edge is essentially at right angles with the cover plate top surface. This arrangement is often advantageous to manufacture.
According to an embodiment of the invention, the sectional plane of the cover plate edge is at an angle of less than 90 degrees, such as 80 - 70 degrees or 30

60 degrees, with the cover plate top surface. An edge that is cut diagonally essentially improves the fastening of the concrete to the steel cover plate, which is advantageous for instance in the case of fire.

According to an embodiment of the invention, the top edge of the beam web plate is provided with one or more web apertures. By means of the web apertures, the beam is technically simple to fill. The web apertures can also be used in the installation of connecting steel rods.
According to an embodiment of the invention, the steel beam is provided with two web plates, the top edges of which are provided with one or more web apertures. This kind of steel beam can, owing to its symmetrical structure, advantageously be used as a centre beam. In certain targets, this kind of steel beam also is suited as an edge beam. The web apertures improve the fastening of the concrete at the top parts of the beam, which is essentially advantageous for instance in the case of fire. According to an embodiment of the invention, the web apertures of two web plates are with respect to each other placed at an essentially identical location in relation to the cover plate lengthwise axis. For instance connecting steel rods can advantageously be installed in this kind of a steel beam.
According to an embodiment of the invention, the web apertures of two web plates are with respect to each other at least partly located in different spots of the cover plate in relation to the lengthwise axis. A structure that is at least partly asymmetrical further improves the fastening to the concrete.
According to an embodiment of the invention, the steel beam has one web plate, the top edge of which is provided with one or more web apertures. This kind of steel beam can advantageously be used for instance as an edge beam.
According to an embodiment of the invention, the web plate is fastened to the bottom plate so that the bottom edge of the web plate is located at a distance from the bottom plate edge. The bottom plate edge located at a distance simplifies the manufacturing process of a steel beam and is advantageous in the installation of the concrete and in concrete casting. According to an embodiment of the invention, the web plate is fastened to the bottom plate, so that the bottom edge of the web plate is located at a distance of 10-200 mm from the bottom plate edge. Preferably the bottom edge of the web plate is located at a distance of for instance 10-50 mm or 50-150 mm, such as 90-150 mm, from the bottom plate edge. In a cavity slab application, the center beam has an advantageous distance 90-150 mm on both sides. The same applies to the edge beam on the side of the cavity slab. The edge beam has an advantageous distance 10-50 mm on the side of the exterior wall (or aperture). In other applications, such as on-site casting, composite slab, casing slab etc., the distance is preferably for example 50-150 mm.
According to an embodiment of the invention, the web plate is placed at an angle of 90 degrees with respect to the bottom plate. In certain applications, this brings structural advantage. Moreover, this kind of beam is economical to manufacture.
According to an embodiment of the invention, the web plate is placed at an angle of 80-70 degrees with respect to the bottom plate. The steel elements of this kind of a steel beam are particularly advantageously fastened to concrete, and it also is advantageous to cast. Moreover, the wedge created at the beam edge when casting concrete in part further reinforces the structures.
According to an embodiment of the invention, the cover plate, the bottom plate and the web plate include installation apertures, such as air bleeding apertures and reinforcing apertures. These make the use of the beam more versatile and simple.
According to an embodiment of the invention, the steel beam is provided with one or more fire resistant steel rods. They are advantageously used in targets where a good fire resistance is required. They can advantageously be used for replacing the fire protection of the plates.
According to an embodiment of the invention, the steel beam is provided with one or more composite steel rods, such as seam irons. By using these kind of structures, the structures are made particularly bearing.
According to an embodiment of the invention, the inside of the steel beam is at least partly filled with concrete and/or fibre concrete. This kind of steel beam is economical to manufacture, and it also simplifies and speeds up the erection of the steel beam at the building site. In certain targets, essential advantage can be gained by using for instance fibre concrete application. Fibre concrete can advantageously be used for making support-like structures for instance in the cover part and/or the web apertures, which essentially reinforce the steel beam. In composite beams, fibre concrete advantageously reinforces also the ends of the slabs to be connected, such as cavity slabs.
By filling the inside of the steel beam at least partly with concrete and/or fibre concrete, the need for supporting the steel beam in the assembly step is reduced. Partial concrete application in the interior also supports the beam, in which case the employed ingredient strengths can be smaller in proportion.
According to an embodiment of the invention, the steel beam is provided with a surface slab. By means of the surface slab, the steel beam is advantageously made more solid. In the steel beam according to the invention, a relatively thin surface slab can be used, because the structure of the cover plate advantageously prevents the concrete from detaching from the steel structures.
According to an embodiment of the invention, the steel beam is provided with one or more connecting elements, such as pins, wedges and/or plates. By means of the connecting elements, the steel beams are further solidified, and they can be securely attached for instance to cavity slabs and on-site cast slabs.
According to an embodiment of the invention, the cover plate, the bottom plate and/or the web plate are provided with concrete elements and/or fibre concrete elements.
According to an embodiment of the invention, the steel beam is provided with one or more on-site cast slabs, cavity slabs, composite slabs and/or cover slabs. These embodiments facilitate an even more versatile use of the beam according to the invention.
According to an embodiment of the invention, the steel beam is a reinforced concrete composite beam and/or a support beam. In certain applications with the composite beam solution, the beam functions in fires even if the bottom plate should lose its strength as the temperature rises. For instance reinforcing steel rods are well resistant to load strain, and in the case of fire, the beam remains erect for a long time when using for instance fibre concrete pins/wedges/slabs.
The connecting elements employed between the surface slab and the steel beam are particularly edge recesses, web apertures, web projections and connecting concrete elements.
The connecting elements employed between the concrete inside the steel beam and the steel beam made of steel are particularly web recesses, edge recesses, installation apertures, fireproof reinforcement steels, connecting steel rods, connecting concrete elements and the slab system.
Connecting elements employed between the steel beam and the slab system are particularly web apertures, installation apertures, connecting steel rods such as seam irons, connecting concrete elements, concrete surface slab and the slab system. The support of the slab system against the steel beam during a fire is carried out by intermediation of said connecting elements, so that the fire resistance requirements are fulfilled, even if the bottom plate would melt completely owing to the heat.
The fire resistance requirements of a steel beam according to the invention are advantageously met by connecting to the steel beam one or several fireproof reinforcement steels and/or by protecting the bottom surface of the bottom plate by for example fireproof paint. When connecting on-site cast slabs, composite slabs or casing slabs to the steel beam, the fire resistance requirements of the steel beam can be fulfilled even without using fireproof reinforcement steels or without fire protecting the bottom surface of the bottom plate.
All concrete elements, such as the interior of the steel beam, the concrete connecting elements, the slab system and the surface slab can advantageously be cast simultaneously, or then step by step, as is suggested elsewhere in this application.
Advantageously the fireproof reinforcement steels can be attached to the end plates of the steel beam by welding, and in some cases this method improves the optimal cooperation between the steel and the concrete.
By means of special connecting elements, fireproof reinforcement steels can advantageously be attached to the web plates of the steel beam, and in some cases this improves the optimal cooperation of steel and concrete.
Preliminary lifting of the beam is advantageous from the point of view of the operability of the whole system. With a steel beam according to the invention, the preliminary lifting can advantageously be carried out by using modest force, even if the web plates were not cut in a curved shape. The required force is reduced by the web apertures.
Among known composite beams, the steel beam according to the invention is the only one that can advantageously be compiled without using an interior support in the steel beam for supporting the plates, or without supporting the plate by a lifting magnet or another similar method. This makes the steel beam a preferable solution that is fast to compile, and the manufacturing of the steel beam can advantageously be automated.
The steel beam according to the invention can advantageously be compiled in the following order:

the cover plate, the bottom plate and the web plates are cut,
the bottom plate is arranged on a level surface,
the web plates are lowered on top of the bottom plate, supported in a vertical position, and the web plates are welded to the bottom plate,
the steel beam is subjected to preliminary lifting, and at the same time the cover is attached to the top parts of the web plates by short welds,
the cover plate and the web plates are welded together.

In an advantageous manufacturing process of the steel beam according to the invention, the cover plate is installed on top of the web plates. A support plate or mandrel is not needed inside the casing. The cover plate, the web plates and the bottom plate can be joined by fillet welding. The compiling step can be rapidly carried out even manually, and the structure enables an automated manufacturing. Assembly welding can be carried out in two steps, for example at the running rate of 1000 mm/min.
By using symmetrical or inverted structures, material losses are not created in the cutting of the web plate and the cover plate. When using web projections of the web plate, said web projection aligns the web plate in the right spot, and there is no need for interior support.
The number of the cover plate projections may vary on a wide scale. One embodiment is for example a straight serrated edge, in which case there are not created any wide edge recesses as such.
One preferred embodiment of a composite beam is that the cover plate has edge recesses or a serrated edge, but the web plates do not have any web apertures, the interior of the steel beam is not filled with concrete, and the fire protection of the steel beam is carried out by protecting the bottom surface of the bottom plate. This alternative is highly advantageous both economically and as regards manufacturing technique. In practical use, the cooperation between the steel beam and the surface slab functions optimally. Possible melting of the bottom plate in case of fire is slowed down by providing fire protection on the bottom surface of the bottom plate.
A preferred embodiment of the composite beam is that the other edge of the cover plate is provided with edge recesses or a serrated edge, and that the web plate arranged on the same side of the beam is provided with web apertures and web projections. The other edge of the cover plate is straight, and the web plate located on the same side of the beam does not have any web apertures at all. The interior of the steel beam is normally filled with concrete. Both economically and as regards manufacturing technique, this alternative is a highly advantageous solution as an edge beam. In practical use, the cooperation between the steel beam, the concrete provided inside the beam and the surface slab functions optimally.

Detailed description of the invention

The invention is explained in more detail below, with reference to the appended drawings.
Figure 1 shows a cross-section of a steel beam with inclined web plates.
Figure 2 shows a cross-section of a steel beam with straight web plates.
Figure 3 shows a cross-section of a steel beam provided with a cavity slab.
Figure 4 is a top-view illustration of a steel beam with a smooth-edged cover plate.
Figure 5 is a top-view illustration of a steel beam where the cover plate is provided with symmetrical edge recesses.
Figure 6 is a top-view illustration of a steel beam where the cover plate is provided with edge recesses located at different spots.
Figure 7 is a side-view illustration of a steel beam where the web plate is provided with web apertures and installation apertures.
Figures 8-10 are top-view illustrations of steel beams where the cover plates are provided with edge recesses, and the web plates are provided with web apertures and web projections.
Figure 11 is a top-view illustration of a steel beam where the cover plate is provided with rectangular edge recesses.
Figure 12 is a top-view illustration of a steel beam where the cover plate is provided with various sizes of edge recesses and edge projections.
Figure 13 illustrates an advantageous manufacturing method of the steel beam.
Figure 1 illustrates a steel beam 1, where the cover plate 2 and the bottom plate 3 are provided with web plates 4, 5 placed at an inclined angle. The edge 2r of the cover plate 2 is located at a distance 6 from the top edge 4y, 5y of the web plates, and respectively the edge 3r of the bottom plate is located at a distance 26 from the bottom edge 4a, 5a of the web plates.
Figure 2 illustrates a steel beam 1, where the cover plate 2 and the bottom plate 3 are provided with web plates 4, 5 arranged at right angles. The edge 2r of the cover plate 2 is located at a distance 6 from the top edge 4y, 5y of the web plates, and respectively the edge 3r of the bottom plate is located at a distance 26 from the edge 3r of the web plates. Moreover, in the second web plate 5 there also can be seen a web aperture 11 arranged essentially at the top edge 5y of the web plate.
Figure 3 illustrates a steel beam 1, where the cover plate 2 and the bottom plate 3 are provided with web plates 4, 5 arranged at an inclined angle. The web plates 4, 5 are at their top edges 4y, 5y provided with web apertures 11, and at their bottom edges 4a, 4a with installation apertures 14. Inside the steel beam 1 s, there is cast concrete 15b. The cover plate 2, where the sectional plane of the edge is sharp, is provided by a surface slab 16 made of concrete 15b. Inside 1s the steel beam, as well as outside the web plates, there also are cast pins 17 and wedges 19 made of fibre concrete 15kb, which pins and wedges are fastened to cavity slabs 18. Inside 1 s the steel beam 1, there are arranged fire resistant steel rods 13, and in the web apertures 11 and installation apertures 14, there are arranged seam irons 12.
Figure 4 illustrates a steel beam 1 where the edge 2r of the cover plate 2 is straight. The cover plate 2 is provided with web plates 4, 5 at a distance 6 from the cover plate edge 2r.
Figure 5 illustrates a steel beam 1, where the edge 2r of the cover plate 2 is provided with edge recesses 7 and respectively edge projections 8. The cover plate 2 is provided with web plates 4, 5 at a distance 6 from the cover plate edge 2r. With respect to each other, the recesses 7 arranged at the cover plate edge 2r are located at essentially identical spots in relation to the lengthwise axis 2k.
Figure 6 illustrates a steel beam 1, where the edge 2r of the cover plate 2 is provided with edge recesses 7 and respectively edge projections 8. The cover plate 2 is provided with web plates 4, 5 at a distance 6 from the cover plate edge 2r. With respect to each other, the recesses made in the cover plate edge 2r are located at essentially different spots in relation to the lengthwise axis 2k.
Figure 7 is a side-view illustration of a web plate 4. The web plate 4 is at the bottom edge 4a provided with round installation apertures, and at the top edge 4y with web projections 10 and web apertures 11. In reversed shape, the web apertures 11 correspond to the filler plate elements 11v left in between. This kind of web apertures 11 can advantageously be manufactured for instance by flame-cutting. Also the round installation apertures 14 are advantageous to manufacture.
Figure 8 illustrates a steel beam 1, where the edge 2r of the cover plate 2 is provided with edge recesses 7 and respectively edge projections. 8. The cover plate 2 is provided with web plates 4, 5 at a distance 6 from the cover plate edge 2r. The web plates 4, 5 are provided with web apertures 11 and web projections 10. The web projections 10 are arranged in the edge recesses 7 of the cover plate 2. With respect to each other, the recesses 7 provided in the cover plate edge 2r are located at essentially identical spots of the cover plate in relation to the lengthwise axis 2k. The web apertures 11 and the web projections 10 are with respect to each other arranged in the web plates 4, 5 at essentially identical spots in relation to the cover plate lengthwise axis 2k.
Figure 9 illustrates a steel beam 1, where the edge 2r of the cover plate 2 is provided with edge recesses 7 and respectively edge projections 8. The cover plate 2 is provided with web plates 4, 5 at a distance 6 from the cover plate edge 2r. The web plates 4, 5 are provided with web apertures 11 and web projections 10. The web projections 10 are arranged in the edge recesses 7 of the cover plate 2. With respect to each other, the recesses 7 in the cover plate edge 2r are located at essentially different spots in relation to the cover plate lengthwise axis 2k. The web apertures 11 and the web projections 10 are arranged in the web plates 4, 5 at essentially identical spots with respect to each other and in relation to the cover plate lengthwise axis 2k.
Figure 10 illustrates a steel beam 1, where the edge 2r of the cover plate 2 is provided with edge recesses 7 and respectively edge projections 8. The cover plate 2 is provided with web plates 4, 5 at a distance 6 from the cover plate edge 2r. The web plates 4, 5 are provided with web apertures 11 and web projections 10. The web projections 10 are arranged in the edge recesses 7 of the cover plate 2. With respect to each other, the recesses 7 of the cover plate edge 2r are located at essentially identical spots in relation to the plate lengthwise axis 2k. The web apertures 11 and the web projections 10 are with respect to each other arranged in the web plates 4, 5 at essentially different spots in relation to the cover plate lengthwise axis 2k.
Figure 11 illustrates a steel beam 1, where the edge 2r of the cover plate 2 is provided with rectangular edge recesses 7, and respectively the cover plate 2 is provided with rectangular edge projections 8. Web plates 4,5 are attached to the cover plate 2 at a distance 6 from the cover plate edge 2r. The recesses 7 provided in the cover plate edge 2r are located at mutually identical spots in relation to the lengthwise axis 2k.
Figure 12 illustrates a steel beam 1, where the edge 2r of the cover plate 2 is provided with various sizes of rectangular edge recesses 7 and rectangular edge projections 8. Web plates 4, 5 are connected to the cover plate 2 at a distance 6 from the cover plate edge 2r. The recesses 7 in the cover plate edge 2r are located at mutually identical spots in relation to the lengthwise axis 2k. In this embodiment, the surface area of the edge recesses 7 serving as connectors between the surface slab and the cover plate 2 and of the frontal surface of the edge projections 8 is advantageously increased, so that the cooperation between the surface slab and the cover plate 2 is further improved, and the strength increased.
Figure 13 illustrates a steel beam 1, where the cover plate 2 and the bottom plate 3 are connected at an inclined angle to the web plates 4, 5. The edge 2r of the cover plate 2 is placed at a distance 6 from the top edge 4y, 5y of the web plates, and respectively the edge 3r of the bottom plate is placed at a distance 26 from the bottom edge 4a, 5a of the web plates. The web plates 4, 5 include web projections 10 that extend to above the top surface of the cover plate 2. The web plates 4, 5 are attached to the cover plate 2 and the bottom plate 3 by fillet welding joints SW.

Claims

A steel beam to be used in the structures of buildings, provided with a steel cover plate, a bottom plate and a web plate, characterized in that the top edge (4y, 5y) of the web plate (4, 5) is fastened to the cover plate (2), so that the top edge (4y, 5y) of the web plate is placed at a distance (6) from the cover plate edge (2r).
A steel beam according to claim 1, characterized in that the top edge (4y, 5y) of the web plate is placed at a distance (6) of 10-50 mm from the cover plate edge (2r).
A steel beam according to claim 1 or 2, characterized in that the edge (2r) of the cover plate is provided with one or more edge recesses (7).
A steel beam according to any of the preceding claims, characterized in that the edge (2r) of the cover plate is provided with one or more edge recesses (7), and the top edge (4y, 5y) of the web plate is provided with one or more web projections (10) that are arranged in the edge recesses (7) of the cover plate edge (2r) for fastening the cover plate (2) and the web plate (4, 5) together.
A steel beam according to any of the claims 1-4, characterized in that both edges (2r) of the cover plate (2) are provided with edge recesses (7) that are with respect to each other placed at essentially identical locations in relation to the cover plate lengthwise axis (2k).
A steel beam according to any of the claims 1-4, characterized in that both edges (2r) of the cover plate (2) are provided with edge recesses (7) that are with respect to each other placed in at least partly different locations in relation to the lengthwise axis (2k) of the cover plate (2).
A steel beam according to any of the claims 1-6, characterized in that the sectional plane of the cover plate edge (2r) is placed essentially at right angles to the top surface of the cover plate (2).
A steel beam according to any of the claims 1-6, characterized in that the sectional plane of the cover plate edge is placed at an angle smaller than 90 degrees with the top surface of the cover plate (2).
A steel beam according to any of the preceding claims, characterized in that the web plate top edge (4y, 5y) is provided with one or more web apertures (11).
A steel beam according to any of the preceding claims, characterized in that the steel beam (1) has one web plate (4, 5), the top edge (4y, 5y) of which is provided with one or more web apertures (11).
A steel beam according to any of the preceding claims, characterized in that the steel beam (1) has two web plates (4, 5), the top edges (4y, 5y) of which are provided with one or more web apertures (11).
A steel beam according to claim 11, characterized in that the web apertures (11) of two web plates (4, 5) are with respect to each other placed at an essentially identical location in relation to the lengthwise axis (2k) of the cover plate (2).
A steel beam according to claim 11, characterized in that the web apertures (11) of two web plates (4, 5) are with respect to each other placed in at least partly different locations in relation to the lengthwise axis (2k) of the cover plate (2).
A steel beam according to any of the preceding claims, characterized in that the web plate (4, 5) is fastened to the bottom plate (3), so that the bottom edge (4a, 5a) of the web plate is placed at a distance (26) from the bottom plate edge (3r).
A steel beam according to any of the preceding claims, characterized in that the web plate (4, 5) is fastened to the bottom plate (3), so that the bottom edge (4a, 5a) of the web plate is placed at a distance of 10-150 mm from the bottom plate edge (3r).
A steel beam according to any of the claims 1-15, characterized in that the web plate (4, 5) is placed at an angle of 90 degrees with respect to the bottom plate (3).
A steel beam according to any of the claims 1-15, characterized in that the web plate (4, 5) is placed at an angle of 80-70 degrees with respect to the bottom plate (3).
A steel beam according to any of the preceding claims, characterized in that the cover plate (2), the bottom plate (3) and the web plate (4, 5) are provided with installation apertures (14), such as air bleeding apertures and steel reinforcing apertures.
A steel beam according to any of the preceding claims, characterized in that the steel beam (1) is provided with one or more fire resistant steel rods (13).
A steel beam according to any of the preceding claims, characterized in that the steel beam (1) is provided with one or more composite steel rods (12), such as seam irons.
A steel beam according to any of the preceding claims, characterized in that the interior (1 s) of the steel beam is at least partly filled with concrete (15b) and/or fibre concrete (15kb).
A steel beam according to any of the preceding claims, characterized in that the cover plate (2), bottom plate (3) and/or web plate (4, 5) are provided with concrete elements (15b) and/or fibre concrete elements (15kb).
A steel beam according to any of the preceding claims, characterized in that the steel beam (1) is provided with one or more connecting elements (17, 19), such as pins, wedges and/or plates.
A steel beam according to any of the preceding claims, characterized in that the steel beam (1) is provided with a surface slab (16).
A steel beam according to any of the preceding claims, characterized in that the steel beam (1) is provided with one or more slabs (18), such as on-site cast slabs, cavity slabs, composite slabs and/or cover slabs.
A steel beam according to any of the claims 1-25, characterized in that in structure, the steel beam (1) is a composite steel-and-concrete beam.
A steel beam according to any of the claims 1-25, characterized in that in structure, the steel beam (1) is a support beam.
The structure of a building, characterized in that it includes one or several steel beams according to claims 1-27.
The use of any of the steel beams according to claims 1-27, or the use of the building structure according to claim 28, in a building.
A method for manufacturing a steel beam to be used in the structures of a building, including a cover plate made of steel, a bottom plate and a web plate, characterized in that the top edge (4y, 5y) of the web plate (4, 5) is attached to the cover plate (2), so that the top edge (4y, 5y) of the web plate is located at a distance (6) from the cover plate edge (2r).