WO2012148260A1

WO2012148260A1 - Composite floor and girder for that purpose

Info

Publication number: WO2012148260A1
Application number: PCT/NL2012/000030
Authority: WO
Inventors: Anne Pieter Van Driesum; Hendrik Eelco Diepeveen
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-04-26
Filing date: 2012-04-26
Publication date: 2012-11-01
Anticipated expiration: 2013-10-26
Also published as: NL1039852A; NL1039852C2; NL1038775C2

Abstract

Composite floor having at least one castellated beam and on either side thereof concrete floor members, in particular prefab concrete floor members, supporting directly or indirectly thereon, wherein the castellated beam is made of steel having a vertical web provided with holes, a top flange and a bottom flange, wherein concrete poured in situ is disposed between the concrete of the floor members and the web, wherein on at least one side, spaced apart above the bottom flange, the web of the beam is provided with supports projecting sideward thereform and extending into the concrete poured in situ.

Description

Composite floor and girder for that purpose

BACKGROUND OF THE INVENTION

The invention among others relates to a beam for an assembled or composite floor and to an assembled or composite floor having one or more of such beams. Composite floors have been assembled from concrete floor members, prefab or poured in situ, and beams of another material, particularly steel. The beams are also called integrated floor beams. In one type of case, integrated floor beams, further to be called "beams" in short, are designed as a castellated beam having transverse holes in the web. The invention furthermore relates to a method for manufacturing a castellated beam for an integrated floor.

A castellated beam, whether or not assembled, has a bottom flange, a top flange and a vertical web connecting the flanges to each other, in which web transverse holes are provided, which transverse holes can be single or double trapezoidal (see for instance WO 01/81685), circular (see for instance WO 2006/ 29057) etcetera.

The castellated beam can be used in particular as support for concrete floor members, such as concrete hollow-core slabs, wide slabs, combination floors of concrete beams having so-called concrete blocks disposed in between them or profiled steel flooring sheets (with or without an insulation layer disposed thereon) on which a concrete layer is poured. The floor members then support on the bottom flange of the castellated beam.

The holes in the castellated beam form a passage for ties extending transverse to the beam and extending to above/inside the floor members. In case of concrete hollow-core slabs the ties extend into the hollow cores extending transverse to the beam, made accessible because at that location the upper wall of the hollow cores has been removed. In case of closed slabs and of concrete hollow-core slabs the rods of the ties may extend in the cup joints between the juxtaposed concrete hollow-core slabs. Subsequently (optionally after longitudinal reinforcement has been disposed along the castellated beam) concrete is disposed along the top flange in order to fill the spaces between the (concrete hollow-core) slabs, the castellated beam and the ties. In this way both floor members are cast together and together with the steel beam they form a composite floor. The holes in the castellated beam can also be used for passage of service lines.

In order to be able to comply with standards for behaviour in case of fire the bottom flange usually should be provided with a layer of fire-retardant and/or fire-resistant material, and/or the bottom flange should be designed sufficiently strong. This in order to prevent that because of the high temperature the bottom flange collapses and the concrete hollow-core slabs at that end may sag, the floor collapsing being a possible result.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a composite floor and a beam for that purpose, particularly a castellated beam, with which an improved behaviour in case of fire can be realised. It is an object of the invention to provide a composite floor and a beam for that purpose, particularly a castellated beam, for which under circumstances said layer of fire-resistant and/or fire-retardant material can be dispensed with or can be thinner or of cheaper material. For achieving at least one of these objects the invention according to one aspect provides a composite floor having at least one castellated beam, and on at least one side, particularly on either side thereof, concrete floor members, particularly prefab concrete floor members, supporting directly or indirectly thereon, the beam being of steel and having a substantially vertical web, a top flange and a bottom flange, wherein concrete poured in situ -further to be called poured concrete- has been disposed between the concrete of the floor members and the web, wherein on at least one side, preferably on either side, at a distance above the bottom flange, the web of the beam is provided with supports projecting sideward therefrom and extending into the poured concrete.

The supports that extend freely sideward, to the outside, that are particularly welded to the web, form a support surface for the concrete body filling the said spaces. The ends of the floor members, that almost form one constructional unity with said concrete body, then have an extra support, in addition to the bottom flange, which extra support is situated at a (safer) distance from the fire side of the floor. Should the bottom flange collapse, the support according to the invention, with the poured concrete surrounding it, provides a replacement for it, like a kind of bracket, like a type of substitute bottom flange.

The supports are wide enough to offer such support to the concrete body that in case of the bottom flange collapsing it remains substantially intact and the load of the floor members is transferred to the castellated beam via said concrete body and the supports.

In horizontal direction the supports may extend into the poured concrete over a distance of more than approximately ¼ of the distance between the web and the edge of the floor member in question, which edge faces the web and is situated at the same level, preferably, in connection with the poured concrete being able to flow there and being able to let a needle vibrator pass, at a distance from said edge. In one embodiment the supports extend up to approximately ½ the distance between the web and the edge of the floor member in question, which edge faces the web and is situated at the same level.

The castellated beam may have a substantially l-shape or H-shape or be a so-called asymmetrical castellated beam (top flange narrower than the bottom flange), having a web in the middle. It is noted that the castellated beam can be assembled per se, for instance two T-shaped beams the webs of which are attached to each other, for instance by welding, wherein the webs may optionally be offset with respect to each other and abut each other with vertical surfaces. In another embodiment the top flange and the bottom flange may be welded to the web that may or may not be assembled. The supports can be strip-shaped having main surfaces and with their main surfaces project from said web, particularly substantially parallel to the bottom flange and transverse, particularly substantially horizontally, preferably perpendicular to the web. The strip-shaped supports may have a largest dimension in castellated beam direction.

In one embodiment he supports are continuous in castellated beam direction. Such an embodiment is easy to manufacture and is able to provide the extra/substitute support over the full length. The bottom flange may then optionally be designed more lightweight at a same target value for the load bearing capacity of the beam.

In another embodiment, which provides the castellated beam with less added weight, the supports are local and they are spaced apart from each other in beam direction.

The supports can be disposed in the tensile zone of the castellated beam, particularly in the tensile zone of the composite beam formed by the castellated beam and the poured concrete. The tensile zone is in that case situated in the lowermost section of the beam, at positive bending moment on the beam.

Preferably, however, the supports are disposed at some distance from the bottom flange, and thus from the heat side. The supports may then be disposed at a distance of approximately 1/3 of the height of the floor members, from the bottom flange. The supports can be disposed at a distance of a few centimetres from the bottom flange, preferably in the range of approximately 3 to approximately 9 cm, preferably approximately 6 cm.

The effectiveness of the supports is enhanced when the supports project in sideward direction over a distance of 1/3 x half the bottom flange width or more. In one embodiment the beam is a castellated beam and the supports are disposed at least at the location of the holes. In a composite floor with castellated beam a concrete body is present that as it were forms an internal concrete cross beam. Said concrete body extends in transverse direction from the one side of the beam, through the hole in the web, to the other side of the beam and in case of concrete hollow-core slabs as floor members furthermore to inside the hollow cores (for instance 0.5 m) of the concrete hollow-core slab in connection with sufficient coverage of the ties. Thus the concrete hollow-core slabs are suspended from the web plate of the beam. In case of the bottom flange of the castellated beam collapsing, large notch stress arises in the concrete body at the location of the lower edge of the holes, as a result of which the concrete body may collapse.

It is an object of the invention to provide a composite floor and a related castellated beam in which this problem will occur less soon.

It is noted that from WO 2007/141370 a Delta beam is known in which the inclined walls are provided with a stiffening strip that is welded flat against it. From EP 0.328.986 a double T-beam is known of which both webs at the inside are provided with stiffening strips that are welded flat against it.

WO 02/465548 shows a tray-shaped beam, wherein the side walls near their upper edges in inward direction are connected to each other by transverse stiffenings in the form of rods, ribs, fins, stiffening plates.

WO 90/00653 shows a composite floor having a U-beam or H-beam against which in the upper half of the web, in the compression zone, on one side an anchoring strip is welded, which is provided with an undulatory longitudinal edge bent outwards with the purpose of enhancing the connection of concrete to the beam.

According to a further aspect the invention provides a composite floor having at least one castellated beam and on at least one side thereof, preferably on either side thereof, concrete floor members, particularly prefab concrete floor members, supporting directly or indirectly thereon, the castellated beam being of steel and having a substantially vertical web provided with holes, a top flange and a bottom flange, wherein poured concrete has been disposed between the concrete of the floor members and the web, wherein at the location of the lower edge of the holes supports are disposed projecting sideward from the web and extending into the poured concrete. Said supports are able to prevent said notch action to a large extent.

The type of supports just mentioned can be combined in a castellated beam with the supports mentioned earlier, if said supports are (also) situated at the lower edge of the holes. Alternatively both functions can be fulfilled by separate supports.

In a cross-sectional plane considered parallel to the web, the supports near the lower edge can be concave, preferably be formed in accordance with a lowermost section of the edge of the holes.

The supports at the lower edge can be formed as insert extending through the holes and supported on the edge thereof. In that way labour is saved on. For ease of placement the insert can be provided with two support parts on either side of the web and a connection in between them situated on the lower edge of the holes, wherein the support parts extend beyond the hole edge in beam direction in order to define an accommodation space for the hole edge.

According to a further aspect the invention provides a castellated beam apparently suitable and intended for a composite floor according to the invention.

In case the beam used should be torsion rigid, particularly during the mounting stage, instead of an I or H-shaped beam a box beam is used the lower wall of which is widened. An example of a rectangular cross-section is a so-called THQ beam, an example of a trapezoidal cross-section is the so-called Delta beam. The THQ beams have the disadvantage of forming a longitudinal cavity, as a result of which sound insulation by the floor is limited. The Delta beam can be filled with concrete indeed, but this requires a lot of material.

It is an object of the invention to provide an l-castellated beam, H- castellated beam or so-called asymmetrical castellated beam (top flange is narrower than the bottom flange) having sufficient torsion rigidity during the mounting stage.

According to one aspect the invention for that purpose provides a castellated beam for floor or roof structures, manufactured of steel having a web provided with holes, a top flange and a bottom flange, which bottom flange is wider than the top flange, furthermore provided with a number of connecting plates situated in transverse direction of the beam spaced apart from the web, and in beam direction spaced apart from each other, which connecting plates are particularly made of steel, and extend between top flange and bottom flange and are attached thereto. During mounting in the work the connecting plates provide the beam with sufficient torsion rigidity without the weight of the beam increasing too much. They can easily be placed and welded to both flanges.

At the location of the side edge of the top flange the connecting plates can be connected to the top flange, preferably against the vertical side of the side edge, and be attached on top of the bottom flange, in order to increase the torsion rigidity.

The connecting plates can be substantially parallel to the web. The connecting plates or partitions can be disposed on the wanted locations, taking the openings in the concrete hollow-core slabs, location of service lines into account, optionally staggered.

Considered in beam direction, the connecting plates can have a length that is shorter than the centre-to-centre distance of the holes in the web of the castellated beam in order to keep those holes freely accessible as much as possible. They may have a length that exceeds their height.

The connecting plates situated on the same side of the web in beam direction, can be situated at an intermediate distance from each other that exceeds, preferably by a few times, the centre-to-centre distance of the holes in the web of the castellated beam. The connecting plates situated on the same side of the web can be situated at a centre-to-centre distance from each other that is n x the centre-to-centre distance of the holes in the web of the castellated beam, wherein n is an integer. If, considered in transverse direction one or more connecting plates are in line with a hole of the web, said connecting plate can be provided with a passage opening in line with said hole. In case the above-mentioned supports are present, in connection with the distribution of the poured concrete it is preferable that considered in transverse direction the connecting plates are spaced apart from the supports. On at least one of their main surfaces the connecting plates can be provided with projections or elevations, such as ribs, lumps. These projections or elevations can be made by deformation (such as by pressing) of the plates or by attaching them thereon, such as by welding. They may for instance project 1 to 2 cm. Ribs can be made by angle bending. Also the upright edges of the connecting plates can be turned towards the web. Due to the elevations, ribs, turned edges an extra engagement surface is provided between poured concrete and beam, as a result of which transfer of shearing forces between the internal concrete beam of poured concrete and beam is enhanced and both are better secured with respect to each other in longitudinal direction.

Castellated beams can be assembled. For that purpose of a combination of two different beams, such as an I-beam and an H-beam, two different I- beams, two different H-beams, etcetera, the two halves obtained after cutting them are welded together, at the location of the cut edges. Thus an assembled steel beam is obtained, also called asymmetrical castellated beam. See for instance WO 2006/ 29057.

It is known to customize the height of an assembled steel beam. In EP 1.687.106 a lowering of the assembled profile is achieved by removing a extra longitudinal strip of material. However, it should be exactly known beforehand how wide that strip should be. In US 3.066.394 the height is increased by incorporating intermediate pieces. According to a further aspect the invention provides an alternative, using a castellated beam having a top flange, a bottom flange and a web extending in between them, wherein the web comprises an upper section and a lower section which are integrally formed with the top flange and the bottom flange, respectively, and are attached to each other, wherein in transverse direction of the beam the upper section and the lower section of the web are situated offset and the uppermost edge sections of the lower section are situated higher than the lowermost edge sections of the upper section.

According to a further aspect the invention provides, described differently, a castellated beam having a top flange, a bottom flange and a web extending in between them, wherein the web comprises an upper section and a lower section which are integrally formed with the top flange and the bottom flange, respectively, and are attached to each other, wherein, considered in a plane of projection substantially parallel to the web, the upper section and the lower section of the web at least partially coincide in the area of the holes. The top flange and web upper section can originate from an I-beam by division. The bottom flange and web lower section can originate from an H- beam by division. Joining both results in a so-called asymmetrical beam.

By means of the invention the height of the assembled beam can be continuously variably set in a surprising, varying way, if both sections are welded together.

Alternatively it is also possible to provide both web parts with holes at the wanted distance from the flanges so that both web parts can be attached to each other by bolt connections instead of by welding. Bolt connections can be realised at a location between the top flange and the bottom flange situated at least near the neutral axis of the assembled castellated beam, so that they are loaded less. If the side edges of the recesses are not inclined, but vertical, the width of the hole to be realised in the assembled beam will always be the same, irrespective of how far both beams have been slid along each other prior to welding. If a certain highest size I-beam and H-beam are started from, any wanted height for the assembled beam can be achieved, particularly through attachment by welding . According to a further aspect the invention provides a method for manufacturing such an assembled beam, wherein a first I or H-shaped initial beam is cut in the web to divide it in longitudinal direction, while forming recesses on the cut edge for the holes of the castellated beam to be manufactured, wherein a second I or H-shaped initial beam is cut in the web in order to divide it in longitudinal direction, optionally also while forming recesses on the cut edge for forming the holes of the castellated beam to be manufactured, wherein one of both parts of the first beam and one of both parts of the second beam are placed with the webs adjacent to each other and after setting the desired distance between top flange and bottom flange are attached to each other, wherein preferably those actions are repeated with the remaining parts of both initial beams.

In a first further embodiment both parts of the assembled beam are welded together. In a second further embodiment both parts are attached to each other by bolt connections.

In a further development of the method according to the invention, after cutting the initial beam that is provided with the bottom flange for the assembled beam to be manufactured and prior to attaching both parts to each other, only the part having the bottom flange of the assembled beam to be manufactured is immersed in a zinc bath. In that way galvanization costs can be saved on. Usually only an entire beam is immersed in a bath of acid and zinc to galvanize the bottom flange in view of corrosion prevention. This is for instance done for beams intended for floors of car parking stations. By using a bolt connection instead of welding, the otherwise required treatment of weld locations, such as greasing the locations beforehand or grinding zinc away on the weld locations, can be saved on.

It may be so that a beam in a composite floor for reasons of strength needs to have such a large web height that the bottom flange will come to lie at a distance below the intended level of the lower surface of the floor members, such as concrete hollow-core slabs. In order to have the floor members support on the beam indeed, raised edge strips are welded at the edges of the bottom flange, on which strips the floor members are able to find support. This requires additional labour and leads to an increase in construction costs. Moreover this may be aesthetically objectionable. It is an object of the invention to improve on this.

According to a further aspect the invention provides a beam, particularly castellated beam, for constructions, having a bottom flange and, extending upwards therefrom and attached thereto at an attachment location, a beam part, such as a web or longitudinal tunnel, wherein the bottom flange extends sideward from said beam part and is pre-shaped to define a hollow shape in cross-section, wherein at least one of the longitudinal edges of the bottom flange is situated higher than the attachment location. This invention therefore can be applied to both said Delta beam and THQ beam and other types of beams for integrated floors, such as IFB, SFB, MSI, and in mainly I-beams or H-beams or combinations thereof. In a composite floor the space above the bottom flange, between the upward beam section and floor members, can be filled again with poured concrete. Prior to that technical lines can be laid on the bottom flange. Alternatively such lines may have been attached to the bottom flange beforehand in the factory, for instance by welding. They may for instance be continuous over the beam length and than be drilled open at the wanted locations in the work for connection to further lines.

Preferably the bottom flange defines a bowl shape in cross-section, wherein both longitudinal edges of the bottom flange are situated higher than the attachment location. Preferably both longitudinal edges are situated at mutually equal height.

The invention furthermore provides a building provided with one or more composite floors according to the invention. The aspects and measures described in this description and the claims of the application and/or shown in the drawings of this application may where possible also be used individually. Said individual aspects may be the subject of divisional patent applications relating thereto. This particularly applies to the measures and aspects that are described per se in the sub claims.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be elucidated on the basis of a number of exemplary embodiments shown in the attached drawings, in which: Figures 1A and 1 B show an isometric view of a first and second embodiment, respectively, of a castellated beam with added supports according to the invention;

Figures 2A-E show a number of examples of castellated beams according to the invention provided with added supports;

Figures 3A and 3B show successive steps in the manufacturing of composite floor using a castellated beam according to the invention, in cross-section;

Figure 3C shows the composite floor of figure 3B, in case of fire;

Figures 4A-E show an isometric view and a side view, respectively, of a torsion reinforced castellated beam according to an exemplary embodiment of the invention, as well as a few alternative details thereof;

Figures 5A-E show a few consecutive steps in the manufacturing of an exemplary embodiment of an assembled castellated beam according to the invention;

Figures 5F and 5G show an alternative way of manufacturing an assembled castellated beam according to the invention; and

Figures 6A-C show a few cross-sections of exemplary embodiments of beams according to the invention provided with concave bottom flanges.

DETAILED DESCRIPTION OF THE DRAWINGS The asymmetrical steel castellated beam 1 in figure 1A comprises a web 2, a bottom flange 3 and a top flange 4. The web 2 was created by joining a web part 2a and a web part 2b that with flanges 3 and 4 form nearly half an H-beam and an I-beam, respectively. Said H-beam and I-beam have been cut earlier in longitudinal direction while also forming recesses in the longitudinal cut edges. After that of each of those beams, halves are each time welded together on the cut edges, in order to form the beam 1 shown in figure 1A, in twofold. In figure 1 the cut edges 5a, 5b are indicated, where the welded joint is made. The recesses cut out earlier then form holes 6, bounded by cut edge sections 7a-d. Cut edge section 7a forms a lower edge of hole 6.

At the level of the hole lower edges 7a, that are situated at approximately 1/3 of the height of the web above the bottom flange 3, steel longitudinal strips 8a, 8b that are parallel to the flanges 3 and 4, are welded to the web 2 on either side thereof, which longitudinal strips 8a, b form added support strips, as will be elucidated below. The longitudinal strips 8a, b have a width of at least 1/3 of the width of the half of the bottom flange 3. They have been arranged in the tensile zone of the castellated beam in use below the neutral axis N of castellated beam , particularly of the composite beam formed by castellated beam and concrete beam to be discussed below at approximately 6 cm from the bottom flange 3, at approximately 1/3 of the height of the concrete hollow-core slabs 20a, b (figure 3A).

The castellated beam 1 in figure 1 B corresponds with the castellated beam of figure 1A, however in this case the longitudinal strips have been replaced by short strip parts 8a, b that have been attached to the web 2 at the location of the lower edges 7a of the holes 6.

In figure 2A it is indicated in cross-section that the short strip parts/support strips 8a, b can form one unity with each other and as were pass through the hole 6. An exemplary embodiment thereof is shown in figures 2D, top view, and figure 2E in which a plate 8 provided with slits 9 having a width corresponding with the thickness of web 2 is shown. The plate 8 can be inserted into the hole 6 and then be brought downwards with the slits 9 over the inclined edge sections 7c into abutment on top of lower edge 7a, in order to be welded thereto. In figure 2B the support strips 8a, b situated on either side of web 2 are welded separately to the web 2, however such that the lower edge 7a is in one plane with the upper surface of the support strips 8a, b. In figure 2C an alternative for the strips 8a, b of figure 2B is shown, wherein a steel support sleeve 8 extends through a hole 6 and is welded therein. Instead of a sleeve a part of a sleeve can also be used, which for instance in the form of a U-shaped gutter is welded to the lower edge of the hole.

In figure 3A the castellated beam of figure 1A is placed in the work, floor 10. At the ends the -symmetrical- castellated beam 1 supports on columns that are not shown. Concrete hollow-core slabs 20a, b are supported with their lower sides 21a, b, on the bottom flange 3, the hollow cores 22a, b of which slab extend transverse to the beam direction. At the end edges at the location of the hollow cores, the concrete hollow-core slabs 20a, b are cutaway from above, so that individual recesses 24a, b that are accessible from above have been formed. The plane 25a, b of the end edges of the concrete hollow-core slabs 20a, b and their so-called bottom flanges 20c, d are shown. The access to the hollow cores 22a, b is closed off by means of a cap 23a,b in the figure shown at the location of the recesses 24a, b.

Between the end edges of the concrete hollow-core slabs 20a, b, particularly the planes 25a, b, and the web 2 of the castellated beam 1 , on either side, spaces 13a,b have been formed, downwardly bounded by the bottom flange 3. In the spaces 13a,b near yet at a slight distance from the bottom flange 3, longitudinal reinforcement rods 11 have been set. Furthermore transverse thereto extending through the holes 6, tie rods 12 have been set in the spaces 3a,b which rods with their ends extend into the recesses 24a, b, to near the caps 23a, b. It will be understood that in actual practice the caps will be further spaced apart from each other and that the rods 12 will then extend to beyond the longitudinal edges of the bottom flange 3. The flat support strips 8a, b extend horizontally sideward from the web 2, to approximately halfway the width of the spaces 13a,b at that location. The distance between the longitudinal edges 8c,d to surfaces 25a, b will in any case be such that a needle vibrator for poured concrete can pass past it. Figure 3B shows that the spaces 13a,b are filled with poured concrete, directions A, wherein the concrete also fills the recesses 24a, b and then surrounds the tie rods 12. Concrete is able to flow through the holes 6, directions B, and furthermore flows between the surfaces 25a, b and edges 8c,d to the area of the reinforcement rods 11 in order to surround them. The spaces 13a,b are completely filled. (NB the hatchings look different in the lowermost parts, but should be the same over the entire spaces 13a,b). After hardening the concrete of the spaces 3a,b with the longitudinal reinforcement 11 as it were forms a concrete beam added to the castellated beam 1. At the location of the holes 6 internal concrete bodies oriented transverse to the web 2 can be seen, which bodies extend between the caps 23a,b and form a kind of concrete dowels, which also form a suspension for the concrete hollow-core slabs 20a, b on the castellated beam !

In case of fire in the space 100 below the floor 10, see figure 3C, the bottom flange 3 may get deformed such that the support function for the lower side 21a, b of the concrete hollow-core slabs 20a, b is no longer fulfilled sufficiently. Also the support for the concrete body forming the concrete beam may be lost to a large extent, possibly resulting in it sliding from the castellated beam 1.

The support strips 8a,b however, provide a kind of wide ledge, bracket, an extra supporting surface for the concrete body, as a result of which said concrete beam is able to retain its integrity and thus is strength. The concrete hollow-core slabs remain sufficiently supported via the said concrete dowels with ties 12, by the castellated beam . In the example shown, in which the support strips with their upper surface sit in one plane with the lower edge 7a of the holes 6, and as it were form a widening for the hole edges, it is prevented that the said concrete dowels collapse as a result of the notch action of the lower edges 7a that would otherwise occur.

It is noted that both said supporting functions can also be performed by horizontally projecting support strips that differ from each other, wherein at a short distance below the lower edges of the holes in the web a support strip continuous in longitudinal direction is arranged and only at the location of the lower edges of the holes a small local support strip for widening the hole edges. In figures 4A and 4B a steel castellated beam 31 is shown having a middle web 32, a bottom flange 33 and a top flange 34, wherein the bottom flange 33 is wider than the top flange 34. Holes 36 are present in the web 32. At locations that are spaced apart in beam direction, between the longitudinal edges 34a, b of the top flange 34 and the bottom flange 33 steel connecting plates 38 are attached to the longitudinal edges by welding, in order to increase the torsion rigidity of the beam 31. Considered in beam direction, the plates may have a length that exceeds their height. In vertical planes the plates 38 are parallel to the web 32 and for instance are at an intermediate distance from each other of twice the centre-to-centre distance of the holes 36. As can be seen in figure 4B sufficient holes 36 remain free for passage of said ties or lines. If a plate 38 covers a hole 36 in an undesirable manner, the said plate 38 can be provided with a hole 39 of suitable size and shape in line with a hole 36.

In figures 4C-E other possible shapes of the connecting plates are shown.

The connecting plates can, as shown, be welded against the lower side of the longitudinal edges of the top flange. Alternatively they can be welded against the vertical sides of said longitudinal edges. The connecting plates can also extend a little over the longitudinal edges of the top flange, wherein from above a welded connection can be made in the corner thus created. In the figures 5A-E the manufacturing of a pair assembled castellated beams is illustrated. In figures 5A and 5B steel initial beam 41 (for instance IP beam) and steel initial beam 51 (for instance HE), respectively, are shown. The flanges 53, 54 are wider than the flanges 43, 44. The height of the webs 42 and 52 can be the same, but this not a requirement.

Both beams 41 , 52 are divided, see cuts C. In figures 5C and 5D the result of cutting is shown, by means of beam parts 41a,41 b and 51a,51b. The cuts result in a battlement-like course of the edge 45a, b 55a, b, wherein by deviating from a cutting line parallel to the beam direction recesses have been formed, with edges 47a, c, 57a, c. It is noted that it can be opted for to cut through one of both beams according to a continuous cutting line parallel to the beam direction and to cut the other beam making, in that case optionally larger, recesses. For forming two assembled castellated beams the beam parts 4 a and 5 a are brought together, and also the beam parts 41b and 51b. The webs are then, not as is usual, brought exactly in line above one another. After the correct height H, figure 5E, has been set the beam parts are welded together on the cut edge sections 45a, 55a and 45b, 55b, but with the webs adjacent to and against each other, see welded seams 65a, b.

In figure 5F a cutting pattern is shown for an alternative way of manufacturing an assembled castellated beam. At the moment of manufacturing a battlement cut, holes 64 intended for bolts are also made, at a selected height. Optionally after the partial beam 52a has been separately immersed in a zinc bath, both beam parts 42a' and 52a' can then be attached to each other by bolt connections 65' that are transverse to the web.

In figures 6A-C steel beams 61 , 71 , 81 are shown with especially designed bottom flanges 63, 73, 83. They are formed as one unity and have a concave shape, wherein the longitudinal edges 63a, b, 73a,b, 83a, b form the highest points of the bottom flanges and may form a predetermined supporting edge for the floor members. As the case may be, the bottom flange can be asymmetrical, in the sense that only one side edge is situated higher than the meeting place bottom flange-web. This may for instance be desirable if the plate on the one side has a smaller thickness than the one on the other side, wherein the supporting edge levels out said difference in thickness.

The above description is included to illustrate the operation of preferred embodiments of the invention and not to limit the scope of the invention. Starting from the above explanation many variations that fall within the spirit and scope of the present invention will be evident to an expert.

I ,

Claims

1. Composite floor having at least one castellated beam, and on at least one side, particularly on either side thereof, concrete floor members, particularly prefab concrete floor members, such as concrete hollow-core slabs, supporting directly or indirectly thereon, the beam being of steel and having a substantially vertical web, a top flange and a bottom flange, wherein poured concrete has been disposed between the concrete of the floor members and the web, characterised in that on at least one side, particularly on either side, at a distance above the bottom flange, the web of the castellated beam is provided with supports projecting sideward therefrom and extending into the poured concrete.

2. Composite floor according to claim 1 , wherein the supports extend in horizontal direction into the poured concrete at least up to approximately ¼ of the distance between the web and the edge of the floor member in question, which edge faces the web and is situated at that location at the same level, preferably up to approximately ½ the distance between the web and the edge of the floor member in question, which edge faces the web and is situated at the same level. 3. Composite floor according to claim 1 or 2, wherein the supports are strip- shaped having main surfaces and with their main surfaces project from said web, particularly substantially parallel to the bottom flange and transverse, particularly substantially horizontally, preferably perpendicular to the web.

4. Composite floor according to claim 3, wherein the strip-shaped supports have a largest dimension in castellated beam direction.

5. Composite floor according to claim 4, wherein the supports are continuous in castellated beam direction.

6. Composite floor according to any one of the claims 1-4, wherein the supports are local and are spaced apart from each other in castellated beam direction.

7. Composite floor according to any one of the preceding claims, wherein the supports are disposed in the tensile zone of the castellated beam, particularly in the tensile zone of the composite beam formed by the castellated beam and the poured concrete.

8. Composite floor according to any one of the preceding claims, wherein the supports are disposed at a distance of approximately 1/3 of the height of the floor members, from the bottom flange.

9. Composite floor according to any one of the preceding claims, wherein the supports are disposed at a distance of a few centimetres from the bottom flange, preferably in the range of approximately 3 to approximately 9 cm, preferably approximately 6 cm.

10. Composite floor according to any one of the preceding claims, wherein the supports project in sideward direction over a distance of 1/3 x half the bottom flange width or more. . Composite floor according to any one of the preceding claims, wherein the supports are disposed at least at the location of the holes.

12. Composite floor according to the preamble of claim 1 or according to claim 11 , wherein the supports are disposed at the lower edge of the holes and extend sideward away from the web into the poured concrete. 3. Composite floor according to claim 12, wherein in a cross-sectional plane considered parallel to the web the supports are concave, preferably are formed in accordance with a lowermost section of the edge of the holes.

14. Composite floor according to claim 12, wherein the supports are formed as insert extending through the holes and supported on the edge thereof.

15. Composite floor according to claim 14, wherein the insert is formed with two support parts on either side of the web and a connection in between them situated on the lower edge of the holes, wherein the support parts extend beyond the hole edge in beam direction in order to define an accommodation space for the hole edge.

16. Castellated beam apparently suitable and intended as castellated beam in the composite floor according to any one of the claims 1-15.

17. Castellated beam for floor or roof structures, manufactured of steel having a web provided with holes and situated substantially vertically in the centre, with a top flange and a bottom flange, which bottom flange is wider than the top flange, furthermore provided with a number of connecting plates situated in transverse direction of the beam spaced apart from the web, and in beam direction spaced apart from each other, which connecting plates are particularly made of steel, extending between top flange and bottom flange and are attached thereto. 18. Castellated beam according to claim 17, wherein at the location of the side edge of the top flange the connecting plates are connected to the top flange, preferably against the vertical side of the side edge.

19. Castellated beam according to claim 17 or 18, wherein the connecting plates are attached on top of the bottom flange.

20. Castellated beam according to claim 17, 18 or 19, wherein the connecting plates are substantially parallel to the web. 21. Castellated beam according to any one of the claims 17-20, wherein considered in beam direction the connecting plates have a length that is shorter than the centre-to-centre distance of the holes in the web of the castellated beam and/or have a length that exceeds their height. 22. Castellated beam according to any one of the claims 17-21 , wherein the connecting plates situated on the same side of the web, in beam direction are situated at an intermediate distance from each other that exceeds, preferably by a few times, the centre-to-centre distance of the holes in the web of the castellated beam.

23. Castellated beam according to claim 22, wherein the connecting plates situated on the same side of the web are situated at a centre-to-centre distance from each other that is n x the centre-to-centre distance of the holes in the web of the castellated beam, wherein n is an integer.

24. Castellated beam according to any one of the claims 17-23, wherein considered in transverse direction one or more connecting plates are in line with a hole of the web, wherein said connecting plate is provided with a passage opening in line with said hole.

25. Castellated beam according to claim 16 and any one of the claims 17- 24, wherein considered in transverse direction the connecting plates are spaced apart from the supports.

26. Castellated beam according to any one of the claims 17-25, wherein on at least one of their main surfaces the connecting plates are provided with projections or elevations, such as ribs, lumps, which for instance project 1 to 2 cm.

27. Castellated beam according to any one of the claims 17-26, wherein the upright edges of the connecting plates have been turned in the direction of the web.

28. Assembled castellated beam having a top flange, a bottom flange and a web extending in between them, wherein the web comprises an upper section and a lower section which are integrally formed with the top flange and the bottom flange, respectively, and are attached to each other, wherein in transverse direction of the beam the upper section and the lower section of the web are situated mutually offset and the uppermost edge sections of the lower section are situated higher than the lowermost edge sections of the upper section.

29. Assembled castellated beam having a top flange, a bottom flange and a web extending in between them, wherein the web comprises an upper section and a lower section which are integrally formed with the top flange and the bottom flange, respectively, and are attached to each other, wherein, considered in a vertical plane of projection substantially parallel to the web, the upper section and the lower section of the web at least partially coincide in the area of the holes.

30. Castellated beam according to claim 28 or 29, wherein the top flange and web upper section originate from an I-beam by division.

31. Castellated beam according to claim 28 or 29, wherein the bottom flange and web lower section originate from an H-beam by division.

32. Castellated beam according to any one of the claims 28-31 , wherein the upper section and the lower section of the web are attached to each other by welding.

33. Castellated beam according to any one of the claims 28-31 , wherein the upper section and the lower section of the web are attached to each other by bolt connections extending transverse to the web. 34. Castellated beam according to claim 33, wherein the bolt connections are situated at least almost on a longitudinal plane that is transverse to the web of the castellated beam and contains the neutral axis of the castellated beam. 35. Method for manufacturing an assembled castellated beam according to any one of the claims 28-34, wherein a first I or H-shaped initial beam is cut in the web to divide it in longitudinal direction, while forming recesses on the cut edge for the holes of the castellated beam to be manufactured, wherein a second I or H-shaped initial beam is cut in the web in order to divide it in longitudinal direction, optionally also while forming recesses on the cut edge for forming the holes of the castellated beam to be manufactured, wherein one of both parts of the first beam and one of both parts of the second beam are placed with the webs adjacent to each other and after setting the desired distance between top flange and bottom flange are attached to each other, wherein preferably those actions are repeated with the remaining parts of both initial beams.

36. Method according to claim 35, wherein both parts of the assembled beam are welded together.

37. Method according to claim 35, wherein both parts of the assembled beam are attached to each other by bolt connections.

38. Method according to claim 37, wherein the bolt connections are realised at a location between the top flange and the bottom flange that is situated at least near the neutral axis of the assembled castellated beam.

39. Method according to claim 37 or 38, wherein after cutting the initial beam that is provided with the bottom flange for the assembled beam to be manufactured and prior to attaching both parts to each other, only the part having the bottom flange of the assembled beam to be manufactured is immersed in a zinc bath.

40. Beam for constructions, having a bottom flange and, extending upwards therefrom and attached thereto at an attachment location, a beam part, such as a substantially vertical web or longitudinal tunnel, wherein the bottom flange extends sideward from said beam part and is pre-shaped to define a hollow shape in cross-section, wherein at least one of the longitudinal edges of the bottom flange is situated higher than the attachment location. 41. Beam according to claim 40, wherein the bottom flange defines a bowl shape in cross-section, wherein both longitudinal edges of the bottom flange are situated higher than the attachment location.

42. Beam according to claim 41 , wherein both longitudinal edges are situated at mutually equal height.

43. Beam according to claim 40, 41 or 42, wherein the beam is an I or H- beam.

44. Beam according to any one of the claims 40-43, wherein the beam is a castellated beam.

45. Building provided with one or more composite floors according to any one of the claims 1-13.

46. Floor structure provided with one or more beams according to any one of the claims 16-43 or beams according to any one of the claims 40-44.

47. Floor provided with one or more of the characterising measures described in the attached description and/or shown in the attached drawings.

48. Beam provided with one or more of the characterising measures described in the attached description and/or shown in the attached drawings. 49. Method provided with one or more of the characterising measures described in the attached description and/or shown in the attached drawings.