Field of the invention

The invention relates to a steel beam as defined in the preamble of independent claim 1. The invention relates to a steel beam, on which bearing structures of a building, such as hollow-core slabs, composite slabs, shell slabs and slabs cast-in-situ, can be supported. During seam grouting or other concreting, the beam is filled with concrete, and after the concrete has hardened, the beam serves as a composite structure.

Various steel beams are known in the art.

Publication WO 90/12173 presents a fire-resistant prefabricated steel beam arranged to act together with concrete as a load-bearing jointing construction for various slabs. The beam comprises two web portions and horizontally projecting flange portions extending beyond the web portions. To achieve a simple beam easy to install at least each web portion with its horizontally projecting flange portion is formed by an integral material strip so that the web portion and the projecting flange portion adjoining it form a jointless entity and so that the web portion is in a slanting position with respect to the flange portion. The web portions are arranged side by side so as to slant towards each other and interconnected at edges closer to each other by means of a horizontal upper part. The edges of the web portions farther apart from each other are interconnected by means of a plate welded to the web portions. Openings are formed close to the upper edges of the web portions and/or in the horizontal upper part to fill the space defined between the upper part of the web portions and the plate with concrete in a manner known per se.

Publication WO 03/100185 presents a steel beam arranged to serve together with concrete as a bearing composite structure for various slab systems, the composite structure comprising a base plate and two web parts arranged side by side at a distance from each other and joined at first ends by means of a horizontal top part. The base plate, web parts and horizontal top part are arranged to form a space that can be filled with concrete. At least one web part is made of a plate part formed of two longitudinal parts of the beam that are at an angle to each other. The plate part is fastened to the base plate and top part in such a manner that the lower part of the web part is at an angle to the base plate and the upper part is substantially perpendicular to the base plate.

Publication WO 03/100186 presents method and means for manufacturing a steel beam, the steel beam serving together with concrete as a bearing composite structure for various slab systems. In the method the base plate, web parts and top plate of the beam are cut from a plate material, the parts are assembled in such a manner that between them, a space is formed for concrete, and the parts are welded together. Web plates are cut to a curved shape according to precambering. Side supports determining the position of the web plates and centre supports determining the location of the top plate are fastened to the base plate at regular intervals in the longitudinal direction of the beam. A force is directed to the base plate that forces the base plate to the curvature defined by the web plates.

Publication WO 03/100187 presents a steel beam that is arranged to serve together with concrete as a bearing composite structure for various slab systems, the composite structure comprising a base plate and two web parts arranged side by side at a distance from each other and joined at first ends of the web parts by means of a horizontal top part, whereby the base plate, web parts and horizontal top part are arranged to form a space that can be filled with concrete. One web part is in a manner known per se made slanted relative to the base plate and a corbel flange extending from it and equipped with openings. The other web part is, in turn, made substantially perpendicular to the base plate and has no openings.

Publication WO 2004/090253 presents steel beam to act together with concrete as a supporting composite structure for different slab systems. The structure is supported at supporting points at the area of the ends and comprises two web parts and horizontal parts extending outside thereof. The web parts are adjacent at a distance from each other and interconnected at one edge of each web part by means of an upper part. The web parts and the upper part constitute a space for concrete. The steel beam comprises at least one peg member whose one end is fastened to the upper part and whose other end is provided with an anchoring expansion or widening section. This peg member is arranged inside the space defined by the web parts and the upper part, in the area of the supporting points.

Objective of the invention

The object of the invention is to provide a steel beam that is cost-effective to produce and to manufacture.

Short description of the invention

The steel beam of the invention is characterized by the definitions of independent claim

1.

Preferred embodiments of the steel beam are defined in the dependent claims. List of figures

In the following the invention will described in more detail by referring to the figures, which

Figure 1 shows a steel beam according to a first embodiment,

Figure 2 shows a part of the steel beam shown in figure 1,

Figure 3 shows the steel beam shown in figure 1 as partly casted into concrete of a slab, Figure 4 is a cross-sectional view of a second embodiment of the steel beam that is casted into a concrete slab,

Figure 5 shows the steel beam shown in figure 4 as cut along line A-A in figure 4, Figure 6 is a cross-sectional view of a third embodiment of the steel beam that is casted into a concrete slab,

Figure 7 shows the steel beam shown in figure 6 as cut along line B-B in figure 6, Figure 8 is a cross-sectional view of a fourth embodiment of the steel beam that is casted into a concrete slab,

Figure 9 shows the steel beam shown in figure 8 as cut along line C-C in figure 8, Figure 10 is a cross-sectional view of a fifth embodiment of the steel beam that is casted into a concrete slab,

Figure 11 shows the steel beam shown in figure 10 as cut along line D-D in figure 10, Figure 12 is a cross-sectional view of a sixth embodiment of the steel beam that is casted into a concrete slab,

Figure 13 shows the steel beam shown in figure 12 as cut along line E-E in figure 12, Figure 14 is a cross-sectional view of a seventh embodiment of the steel beam that is casted into a concrete slab,

Figure 15 shows the steel beam shown in figure 14 as cut along line F-F in figure 14,

Figure 16 shows a part of an eighth embodiment of the steel beam,

Figure 17 shows the steel beam part shown in figure 16 as seen from one end,

Figure 18 shows the steel beam part show in figure 16 as cut along line G-G in figure 17,

Figure 19 shows a seen from the side an alternative configuration of the first elongated web part and/or the second elongated web part of the eight embodiment of the steel beam,

Figure 20 shows as seen from one end a part of a steel beam according to a ninth embodiment,

Figure 21 shows as seen from one end a part of a steel beam according to a tenth embodiment,

Figure 22 shows as seen from one end a part of a steel beam according to an eleventh embodiment,

Figure 23 shows as seen from one end a part of a steel beam according to a twelfth embodiment,

Figure 24 shows as seen from one end a part of a steel beam according to a thirteenth embodiment, and

Figure 25 shows as seen from one end a part of a steel beam according to an fourteenth embodiment.

Detailed description of the invention

The figures show various embodiments of the steel beam arranged to serve together with concrete (not marked with a reference numeral) as a bearing composite structure for various slab systems 6 which are cast completely or partially on site.

The steel beam comprises an elongated planar base plate 1 having a longitudinal center line 2. The elongated planar base plate 1 has preferably, but not necessarily, an elongated rectangular shape that may have a width between about 200 mm and about 600 mm, such as between about 350 mm and about 550 mm or between about 400 mm and about 500 mm.

The steel beam comprises a first elongated web part 3, which has a first lower end 4 that may be in the form of a first lower edge that is joined to the elongated planar base plate 1, wherein the first lower end 4 of the first elongated web part 3 is essentially parallel with the longitudinal center line 2 of the elongated planar base plate 1. The first elongated web part 3 has preferably, but not necessarily, an elongated rectangular shape.

The first elongated web part 3 and the elongated planar base plate 1 may be joined by welding. It is also possible that the first elongated web part 3 and the elongated planar base plate 1 are parts of a hot rolled beam element (not marked with a reference numeral).

The steel beam comprises a first corbel flange 5 extending from the elongated planar base plate 1 for supporting a part of the slab system 6 that may be in the form of a first slab (not shown in the drawings).

The steel beam comprises at least one transversal reinforcement bar 7 that is joined to the first elongated web part 3 so that said least one transversal reinforcement bar 7 is substantially parallel with the elongated planar base plate 1 and so that said least one transversal reinforcement bar 7 extend in a transverse direction with respect to the longitudinal center line 2 of the elongated planar base plate 1. Said at least one transversal reinforcement bar 7 may be fastened at the factory where the steel beam is manufactured or at the building site when the steel beam is used for example in connection with the assembly of a first elongated reinforcement cage 9 that is presented in greater detail later in this text.

The first elongated web part 3 of the steel beam may be formed of an elongated planar steel plate as in the embodiments shown in figures 1 to 11. In the embodiments shown in figures 12 to 15, the first elongated web part 3 of the steel beam is a steel plate that is a part of a hot rolled beam element. In the embodiments shown in figures 12 to 15, the first elongated web part 3 of the steel beam may alternatively be formed of an elongated planar steel plate.

If the first elongated web part 3 of the steel beam is formed of an elongated planar steel plate or is a part of a hot rolled beam element, the first elongated web part 3 is preferably, but not necessarily, provided with first openings 8. A purpose of the first openings 8 may be to allow concrete to flow into an space 16 of the steel beam, if the steel beam is provided with such space 16, and/or may be to allow installing of reinforcement for the slab system 6 and/or for allowing piping for heating, water or electricity to pass through the steel beam and/or to provide for shear connection for composite action between the steel beam and the concrete of the slab system 6 that is in the first openings 8 by forming "concrete dowels" in the first openings 8 and/or for supporting the slab system 6 through the first openings 8 in case of fire.

If the first elongated web part 3 is provided with first openings 8, the first openings 8 may have an area between about 300 mm ² and about 30000 mm ² , preferable between about 700 mm ² and about 17500 mm ² , more preferable between about 1250 mm ² and about 5000 mm ² . If the first elongated web part 3 is provided with first openings 8, the first openings 8 may have a circular form having a diameter between about 20 mm and about 200 mm, preferable between about 30 mm and about 150 mm, more preferable between about 40 mm and about 80 mm.

The first elongated web part 3 of the steel beam may, as shown in the embodiments illustrated in figures 16 to 25, comprise a plurality of steel reinforcement bars 30, which form an elongated planar net structure. A purpose of such elongated planar net structure is to provide shear- and longitudinal reinforcement and/or to allow concrete to flow into an space 16 of the steel beam, if the steel beam is provided with such space 16, and/or to allow installing of reinforcement for the slab system 6 and/or for allowing piping for heating, water or electricity to pass through the steel beam.

The steel beam may comprise a first elongated reinforcement cage 9 comprising a plurality of essentially identical frames 10 made of reinforcement bar arranged in parallel and a plurality of elongated reinforcement bars 11 to which the frames 10 are joined in a spaced relationship to each other. If the steel beam comprises a first elongated reinforcement cage 9, the longitudinal center line 2 of the elongated planar base plate 1 is essentially parallel with a first central axis 26 of the first elongated reinforcement cage 9.

The first elongated reinforcement cage 9 may be fastened to the first elongated web part 3 or alternatively be a part that is configured to be fastened to the first elongated web part 3 for example on site.

The steel beam may, as in the first embodiment illustrated in figures 1 to 3, as in the second embodiment illustrated in figures 4 and 5, as in the third embodiment illustrated in figures 6 and 7, as in the fourth embodiment illustrated in figures 8 and 9, as in the fifth embodiment illustrated in figures 10 and 11, and as in the eighth embodiment illustrated in figures 16 to 18, comprise a second elongated web part 12 that has a second lower edge 13 that is joined to the elongated planar base plate 1 at a distance from the first elongated web part 3 so that the first lower end 4 of the first elongated web part 3 and the second lower edge 13 of the second elongated web part 12 are essentially parallel.

If the steel beam comprises a second elongated web part 12, the first elongated web part 3 and the second elongated web part 12 may be connected by means of transversal reinforcement bars 7, which are substantially parallel with the elongated planar base plate 1, and which extend in a transverse direction with respect to the longitudinal center line 2 of the elongated planar base plate 1 at a distance from the elongated planar base plate 1.

If the steel beam comprises a second elongated web part 12, a first upper edge 14 of the first elongated web part 3 and a second upper edge 15 of the second elongated web part 12 are essentially parallel.

If the steel beam comprises a second elongated web part 12, a first upper edge 14 of the first elongated web part 3 and a second upper edge 15 of the second elongated web part 12 may be essentially parallel to the elongated planar base plate 1.

If the steel beam comprises a second elongated web part 12, the first elongated web part 3 and the second elongated web part 12 may be slanted relative to the elongated planar base plate 1 so that the distance between first upper edge 14 of the first elongated web part 3 and the second upper edge 15 of the second elongated web part 12 is smaller than the distance between first lower end 4 of the first elongated web part 3 and the second lower edge 13 of the second elongated web part 12.

If the steel beam comprises a second elongated web part 12, the steel beam comprises an open 16 limited by the first elongated web part 3, the second elongated web part 12 and the elongated planar base plate 1. The space 16 is configured to be filled with concrete.

If the steel beam comprises a second elongated web part 12, the steel beam comprises a second corbel flange 17 extending from the elongated planar base plate 1 for supporting a part of a slab system that may be in the form of a second slab (not shown in the drawings).

If the steel beam comprises a second elongated web part 12, first upper edge 14 of the first elongated web part 3 and the second upper edge 5 of the second elongated web part 12 being joined together along the first upper edge 14 of the first elongated web part 3 and the second upper edge 15 of the second elongated web part 12, as in tenth embodiment shown in figure 21, in the eleventh embodiment shown in figure 22, in the thirteenth embodiment shown in figure 24, and in the fourteenth embodiment shown in figure 25.

If the steel beam comprises a second elongated web part 12, the transversal reinforcement bars 7 may be connected to the first elongated web part 3 at the first upper edge 14 of the first elongated web part 3, and the transversal reinforcement bars 7 being connected to the second elongated web part 12 at the second upper edge 15 of the second elongated web part 12, as in the second embodiment shown in figures 4 and 5 and in the third embodiment shown in figures 6 and 7.

If the steel beam comprises a second elongated web part 12, the transversal reinforcement bars 7 may be connected to the first elongated web part 3 by means of at least one first elongated reinforcement bar 18 fastened at and extending along the first upper edge 14 of the first elongated web part 3, and the transversal reinforcement bars 7 may be connected to the second elongated web part 12 by means of at least one second elongated reinforcement bar 19 fastened at and extending along the second upper edge 15 of the second elongated web part 12, as in the fourth embodiment shown in figures 8 and 9 and in the fifth embodiment shown in figures 10 and 11. Another purpose of such of at least one first elongated reinforcement bar 18 and such at least one second elongated reinforcement bar 19 is to provide shear connection between the steel beam and the concrete of the slab system 6 and to provide longitudinal reinforcement especially if the first elongated web part 3 is in the form of an elongated planar steel plate free of first openings 9 and/or if the second elongated web part 12 is in the form of an elongated planar steel plate free of second openings 20. If the steel beam comprises a second elongated web part 12, the space 16 may be an open space having an open top 29 between the first upper edge 14 of the first elongated web part 3 and the second upper edge 15 of the second elongated web part 12.

If the steel beam comprises a second elongated web part 12, the space 16 may be an open space having an open top 29 between the first upper edge 14 of the first elongated web part 3 and the second upper edge 15 of the second elongated web part 12, and the first upper edge 14 of the first elongated web part 3 and the second upper edge 15 of the second elongated web part 12 may be connected solely by transversal reinforcement bars 7.

If the steel beam comprises a second elongated web part 12, the space 16 may be an open space having an open top 29 between the first upper edge 14 of the first elongated web part 3 and the second upper edge 15 of the second elongated web part 12 and the steel beam may comprise a first elongated reinforcement cage 9 comprising a plurality of essentially identical frames 10 made of reinforcement bar and a plurality of elongated reinforcement bars 11 to which the frames 10 are joined in a spaced relationship to each other such that the first elongated reinforcement cage 9 has a first central axis 26 such that the first longitudinal center line 2 of the elongated planar base plate 1 is essentially parallel with the first central axis 26 of the first elongated reinforcement cage 9, and such that the first elongated reinforcement cage 9 is arranged at least partly in the space 16, as illustrated in the embodiments of the steel beam shown in figures 1 to 11. The first elongated reinforcement cage 9 as described before is applicable also for the embodiments of the steel beam according to figures 16 to 25.

If the steel beam comprises a second elongated web part 12 and a first elongated reinforcement cage 9, the first elongated reinforcement cage 9 may be fastened to the first elongated web part 3 and to the second elongated web part 12.

If the steel beam comprises a second elongated web part 12 and a first elongated reinforcement cage 9, the first elongated reinforcement cage 9 may be fastened to the first elongated web part 3 and to the second elongated web part 12 by means of said at least one transversal reinforcement bar 7 so that the first elongated reinforcement cage 9 is fastened to said at least one transversal reinforcement bar 7.

If the steel beam comprises a second elongated web part 12, the second elongated web part 12 may be formed of an elongated planar steel plate, as in the embodiments shown in figures 1 to 11. The second elongated web part 12 of the steel beam may be a steel plate that is a part of a hot rolled beam element.

If the steel beam comprises a second elongated web part 12, the second elongated web part 12 may be provided with second openings 20. A purpose of the second openings 20 may be to allow concrete to flow into the space 16 of the steel beam, and/or may be to allow installing of reinforcement for the slab system 6 and/or for allowing piping for heating, water or electricity to pass through the steel beam and/or to provide for shear connection for composite action between the steel beam and the concrete of the slab system 6 that is in the second openings 20 by forming "concrete dowels" in the second openings 20 and/or for supporting the slab system 6 through the second openings 20 in case of fire.

If the steel beam comprises a second elongated web part 12 provided with second openings 20, the second openings 20 may have an area between about 300 mm ² and about 30000 mm ² , preferable between about 700 mm ² and about 17500 mm ² , more preferable between about 1250 mm ² and about 5000 mm ² .

If the steel beam comprises a second elongated web part 12 provided with second openings 20, the second openings 20 may have a circular form having a diameter between about 20 mm and about 200 mm, preferable between about 30 mm and about 150 mm, more preferable between about 40 mm and about 80 mm.

If the steel beam comprises a second elongated web part 12, the second elongated web part 12 of the steel beam may, as shown in the embodiments illustrated in figures 16 to 25, comprise a plurality of steel reinforcement bars 30, which form an elongated planar net structure. The second elongated web part 12 of the steel beam may be composed of a plurality of steel reinforcement bars 30, which form an elongated planar net structure. A purpose of such elongated planar net structure is to provide shear and longitudinal reinforcement and/or to allow concrete to flow into an space 16 of the steel beam, if the steel beam is provided with such space 16, and/or to allow installing of reinforcement for the slab system 6 and/or for allowing piping for heating, water or electricity to pass through the steel beam.

In the sixth embodiment of the steel beam illustrated in figures 12 and 13, the first elongated web part 3 extends essentially perpendicularly with respect to the elongated planar base plate 1, and the first elongated web part 3 is joined to the elongated planar base plate 1 essentially at the longitudinal center line 2 of the elongated planar base plate 1. In such embodiment the steel beam may comprise an elongated planar top plate 21 having a second longitudinal center line 22 along which the elongated planar top plate 21 is joined to a first upper edge 14 of the first elongated web part 3 so that the elongated planar base plate 1 and the elongated planar top plate 21 are essentially parallel.

If the first elongated web part 3 extends essentially perpendicularly with respect to the elongated planar base plate 1, and if the first elongated web part 3 is joined to the elongated planar base plate 1 essentially at the first longitudinal center line 2 of the elongated planar base plate 1, at least one first elongated rebar 18 may be fastened at and extending along the first upper edge 14 of the first elongated web part 3. A purpose of such of at least one first elongated reinforcement bar 18 is to provide shear- and longitudinal reinforcement especially if the first elongated web part 3 is in the form of an elongated planar steel plate free of first openings 9.

If the first elongated web part 3 extends essentially perpendicularly with respect to the elongated planar base plate 1, and if the first elongated web part 3 is joined to the elongated planar base plate 1 essentially at the first longitudinal center line 2 of the elongated planar base plate 1, at least one stud 23 provided with a widened head 24 may be joined to the first elongated web part 3 so that said least one stud 23 provided with a widened head 24 extend substantially parallel with the elongated planar base plate 1 and so that said least one stud 23 provided with a widened head 24 extend in a transverse direction with respect to the first longitudinal center line 2 of the elongated planar base plate 1 at a distance from the elongated planar base plate 1.

If the first elongated web part 3 extends essentially perpendicularly with respect to the elongated planar base plate 1, and if the first elongated web part 3 is joined to the elongated planar base plate 1 essentially at the first longitudinal center line 2 of the elongated planar base plate 1, and if the steel beam comprises an elongated planar top plate 21 having a second longitudinal center line 22 along which the elongated planar top plate 21 is joined to a first upper edge 14 of the first elongated web part 3, or if at least one first rebar 18 is fastened at an extending along the first upper edge 14 of the first elongated web part 3, the steel beam may comprise a first elongated reinforcement cage 9 comprising a plurality of essentially identical frames 10 made of reinforcement bar arranged in parallel and a plurality of elongated reinforcement bars 11 to which the frames 10 are joined in a spaced relationship to each other, and a second elongated reinforcement cage 25 comprising a plurality of frames 10 made of reinforcement bar arranged in parallel and a plurality of elongated reinforcement bars 11 to which the frames 10 are joined in a spaced relationship to each other, so that the first elongated reinforcement cage 9 and the second elongated reinforcement cage 25 being arranged on opposite sides of the first elongated web part 3. Such first elongated reinforcement cage 9 and such second elongated reinforcement cage 28 may be supported and/or fastened to studs 23 joined to the first elongated web part 3 as presented earlier, if the steel beam is provided with studs 23.

It is apparent to a person skilled in the art that as technology advances, the basic idea of the invention can be implemented in various ways. The invention and its embodiments are therefore not restricted to the above examples, but they may vary within the scope of the claims.