WO2009010786A2

WO2009010786A2 - Method of building construction and method of fabricating building elements

Info

Publication number: WO2009010786A2
Application number: PCT/GB2008/050558
Authority: WO
Inventors: John Rodgers
Original assignee: Impaq Ltd
Priority date: 2007-07-16
Filing date: 2008-07-10
Publication date: 2009-01-22
Also published as: GB0713756D0; GB2464076C; GB2464076B; GB201002562D0; WO2009010786A3; GB2464076A

Abstract

A method of fabricating a building constructional element comprises forming an elongate steel web (1) having first and second linear edges (2 and 3) and with the first edge (2) having a plurality of tabs (4) projecting outwardly therefrom, forming first and second elongate linear flanges (7 and 8) corresponding in length to the first and second edges, and forming in said first flange (7) a plurality of apertures (9) corresponding in position and dimensions to the respective tabs (4) on said first edge of the web. The second flange (8) is then welded to the second edge (3), the apertures (9) in the first flange are located over the tabs (4) on the first edge of the web, and then the tabs are welded to the flanges around said apertures. The tabs (4) can project from the surface of the flange to facilitate attachment of other building components, for example concrete floor decking. The flanges may be sheets joined together by a plurality of the webs to form a steel building panel offering substantial scope for new building design.

Description

METHOD OF BUILDING CONSTRUCTION AND METHOD OF FABRICATING

BUILDING ELEMENTS Field of the Invention

This invention relates to a method of building construction, in particular for forming concrete floors in buildings and to a method of fabricating building elements. Background to the Invention

In the construction of buildings using steelwork and concrete, floors are usually created by locating pressed steel channel members across the horizon- tal steel I-beams, and casting concrete in and on the channel members to provide the floors. Before the concrete is poured, vertical studs are welded to the intersections of the I-beams and the channel members to couple loading from the concrete into the beams and to hold the channel members in place on the I- beams. The studs also serve as anchor points for holding steel reinforcement grids in place while concrete is poured over them so that the grids become embedded in the concrete.

The welding of the studs is a time-consuming skilled process, and it is difficult to ensure that sufficient studs are provided in the right places, and that all the welds are satisfactory. Proper testing of each weld would further add to time and costs and is therefore often not carried out. It may therefore be difficult to ensure that the construction has the load capabilities for which it was designed without "over-engineering" the provision of studs to compensate for likely deficiencies. This in turn further increases costs and delays.

Many modern building constructions call for the use of steel panels con- sisting of parallel steel plates or sheets connected by fins or ribs extending between them. The welding of such fins or ribs is a specialised operation, requiring costly welding techniques and specialised equipment, which limits the number of fabrication sites capable of producing them. This is because, while the welding of the ribs to the first sheet can readily be achieved conventionally, when the second sheet is to be welded, access to the internal connection between the rib or fin and the sheet is not available for normal welding equipment. This in turn means that the welds either have to be achieved using special equipment which can operate in the confined space between the sheets (and this can only be done if the sheets are exactly parallel, limiting design possibilities) or by welding from the exterior, which requires achieving fusion temperature of the metal through its entire thickness. This cannot be achieved by ordi- nary welding equipment and so is confined to specialised fabrication plants. Summary of the Invention

According to one aspect of the invention, a method of fabricating a building constructional element comprises: a) forming an elongate steel web having first and second linear edges and with the first edge having a plurality of tabs projecting outwardly therefrom: b) forming first and second elongate linear flanges corresponding in length to the first and second edges, and forming in said first flange a plurality of apertures corresponding in position and dimensions to the respective tabs on said first edge of the web; c) welding the second flange to the second edge; d) locating the apertures in the first flange over the tabs on the first edge of the web; and e) welding the tabs to the flanges around said apertures. Other features of the invention are defined in the claims.

The invention provides a simplified method of floor construction avoiding the need for welding of studs in situ, thereby greatly accelerating the construction and enabling design strengths to be achieved more reliably.

The invention also provides a method of building construction in which twin-walled steel panels of complex shapes can readily and reliably be manufactured on-site without complex welding equipment, reducing costs and offering greater architectural freedom.

It further provides methods of building construction in which interconnections between one beam and another in a building, or between a beam and an- other component, can be achieved by fabricating beams with projecting tabs in accordance with the method of the invention, and attaching the additional beams of other components to the tabs. Brief Description of the Drawings

In the drawings, which illustrate exemplary embodiments of the invention:

Figure 1 is an exploded perspective view of a portion of a beam or column showing the components before assembly; Figure 2 is a perspective view of one end of an I-beam produced in accordance with the method of the invention;

Figure 3 is a perspective view of one end of a box beam produced in accordance with the invention;

Figure 4 is a perspective view of a portion of another I-beam produced in accordance with the invention;

Figures 5, 6 and 7 illustrate alternative shapes of beam which can be produced by the method of the invention;

Figures 8, 9 and 10 show alternative forms of web which can be employed in the method of the invention; Figure 10a is a plan view of the web shown in Figure 10;

Figure 11 is a sectional view of a floor prior to pouring of concrete;

Figure 12 is a perspective view of the floor of Figure 11 ;

Figure 13 is a perspective view of a building panel produced in accordance with the invention; Figure 14 illustrates a curved panel for use in forming a tubular structure, made in accordance with one aspect of the invention;

Figure 15 is a part-sectional view through a floor according to another embodiment of the invention;

Figure 15a is view of two alternative tab shapes to those incorporated in the structure shown in Figure 15;

Figure 16 shows a portion of a roof construction in accordance with one aspect of the invention;

Figure 17 shows a portion of a beam according to yet another aspect of the invention; Figure 18 illustrates the attachment of a side rail to a beam in accordance with the invention; Figures 19 and 20 illustrate alternative methods of attachment of beams to columns in accordance with still further aspects of the invention;

Figure 21 illustrates a prior art method of increasing attachment hole spacing in the conventional methods of attaching a beam to a column; and Figure 22 shows a method in accordance with the invention to replace the method illustrated in Figure 21 . Detailed Description of the Illustrated Embodiment

Referring first to Figure 1 , an I-beam is formed by first cutting a flat steel web member 1 to provide opposed linear edges 2 and 3 from which extend tabs 4 and 5 respectively, spaced at intervals therealong. Apertures 6 may be cut in the web 1 to reduce weight and to provide for the passage of services through the beams when used in buildings, for example. Flanges 7 and 8 are then cut with apertures 9 and 10 respectively corresponding in position, size and shape to the tabs 4 and 5. The flanges 7 and 8 can then be assembled with the web 1 by locating the tabs 4 and 5 in the apertures 9 and 10 and welding the tabs to the flanges around the apertures. The tabs 4 are formed so as to project beyond the upper face of the flange 7, for example to permit the beam to be used in flooring construction as hereinafter described. The tabs 5 locate in the flange 8 flush with the outer face thereof. Figure 2 illustrates an assembled I-beam. In this case it will be seen that the beam is asymmetric, the lower flange being wider than the upper flange. As an alternative to the tab and slot connection described with reference to Figure 1 for the second flange 8, the lower edge 3 of the web 1 can be formed without tabs and simply welded continuously or discontinuously to the flange 8, accord- ing to the specification for the application. The tabs 4 project through the upper flange 7, and may be provided with a hole 11 therethrough to facilitate fixing of other building components, for example concrete-reinforcing mesh where the beam supports a floor.

Figure 3 illustrates a box beam formed by a pair of webs 1 extending be- tween flanges 7 and 8, the webs being coupled to the lower flange 8 in the manner described with reference to Figure 1 , with additional welding along the junction between the web and the inner face of the flange 8. The cavity 12 in the box beam may be filled with concrete or a plastics foam, for example, to create a composite beam having enhanced properties over the basic box beam.

Figure 4 illustrates a section of an I-beam produced in accordance with the invention, the lower flange 8 being continuously welded to the web 1 , while the upper flange 7 has tabs 4 passing through it. These may be shaped or pierced to facilitate connection of additional building elements subsequently.

Cutouts 13 in the web 1 may facilitate the installation of pipework or wiring in a building, and may reduce weight.

While the components illustrated in Figures 1 to 4 have flanges which are straight and parallel to each other, the method of the invention may be used to achieve beams and like components which are of different shapes to suit particular applications. Examples of these are shown in Figures 5, 6 and 7. In Figure 5, the beam tapers along its length, the web 51 reducing in height progressively from one end to the other. In Figure 6, the beam has a straight lower flange 68 and a curved upper flange 67, with the web 61 being profiled to conform with the upper flange curvature, which can be achieved by rolling of the flange. The component shown in Figure 7 curves along its length while the flanges remain parallel to each other. In this case, both flanges 77 and 78 are rolled or cut to achieve the desired curvature, while the web 71 is cut to the de- sired shape.

The projections or tabs can be parallel to the beam longitudinal axis, as illustrated in Figures 1 to 7, or they can be at any angle to the longitudinal axis by forming, bending or curving of the web, as illustrated in Figures 8 to 10a. In Figure 8, the web is curved into a generally sinusoidal shape, while the web shown in Figure 9 is shown with a series of angular bends of differing angles. In Figures 10 and 10a, the tabs are set at right angles to the longitudinal direction of the web by the use of two 90 degree folds and one 180 degree fold to produce a projection from the web, on which the tab is located. The tab may be formed with single or double thickness. The projections may alternate from one side of the web to the other.

Figures 11 and 12 illustrate a method of building construction using beams manufactured in accordance with the invention as supports for flooring. The beams 110, which are produced as described with reference to Figure 2, are spaced apart in the steel frame of a building in conventional manner, with the tabs 111 projecting upwardly. Steel flooring decking 112 of the type having alternating channels 112a and ribs 112b has slots cut therein which correspond in size and position to the upstanding tabs 111. The decking is then simply positioned on the beams 110 with the tabs 111 projecting through the slots; welding is not required, because the loads from the floor are transmitted directly to the beams via the tabs and the decking is held in place sufficiently by the tabs. Steel mesh reinforcement is then laid over the tabs and attached by wire to them in conventional manner so that concrete can be poured on to the decking to form the floor.

Figure 13 illustrates a steel building panel produced by the method of the invention. A plurality of webs 130 are formed with tabs projecting from one or both edges, and one or both steel sheets 131 are formed with corresponding slots or apertures 132 therethrough. Where both sheets 131 have apertures, the panel is assembled by locating each sheet with its slots over the tabs, and then welding the sheets externally at each of the slots to secure the web to the sheets. Alternatively, where one of the sheets 131 is formed without slots, and the webs with tabs on only one edge, the webs are positioned with their plain edges in the correct position on the sheet without slots and welded thereto along each side of the web, this operation being possible only because the slotted sheet is not in position yet. The slotted sheet is then located with its slots receiving the tabs on the upper edges of the webs, and is welded on the outer face of the sheet at each of the slots, joining the tab to the sheet at each loca- tion.

Figure 14 illustrates a building element which is curved so as to form half of a tubular structure. In this case, the inner and outer sheets 141 are each rolled to form a semicircular curve in profile, and one of the sheets is formed with slots to receive tabs projecting from an edge of each of the webs 140, the assembly being essentially the same as with the panel described with reference to Figure 13. It will be appreciated that while Figure 14 illustrates a component of a uniform tubular structure, the method of the invention may be applied to the construction of components having other configurations, for example tapering tubular structures or even irregular shapes.

Figure 15 illustrates an alternative floor construction, which provides for resistance to uplift forces tending to lift the concrete floor slab from the metal decking. The beams 150 are manufactured with projecting tabs 151 which are each provided with a head having outwardly projecting arms 151 a whose undersides make an angle of 90 degrees or less with the vertical portion of the tab to provide anchorage for the concrete slab 152 cast over it. The concrete could be provided with a reinforcing mesh therein, but could instead be a fibre- reinforced concrete.

Figure 15a shows two alternative shapes of tab to that shown in Figure 15, configured to increase the area in contact with the concrete to resist upward shear forces in the event that the configuration in Figure 15 provides insufficient strength. In the first alternative, the tab is formed with a single arm 151 b ex- tending to one side of the tab, while in the other alternative, a plurality of horizontal arms 151 c project from both sides of the tab. While these arms are illustrated as being symmetrical, it will be appreciated that they could be arranged asymmetrically, as required to achieve the desired shear strength.

The slots 153 in the metal decking 154 through which the tabs project have a width sufficient to allow the arms 151 a to pass through. While the body of the tab may be uniformly narrow, it is preferred to shape the tab so that it has a portion 155 adjacent to the beam upper surface which is the same width as the head of the tab, in order to locate the decking positively and avoid the risk of lateral movement before the concrete slab has hardened. It is usual practice to attach(by welding, or by bolting through punched or drilled holes) pieces of steel plate or rolled steel angle (RSA) to columns and beams for attaching secondary components, such as purlins for roofs and side- rails for walls. These require the manufacture of extra components, and extra operations to attach them, and involve difficulty in achieving positional accuracy, owing to the relatively long (typically several metres) members involved, and the wide manufacturing tolerances of standard hot-rolled steel sections. Figure 16 illustrates a method of roof construction, in which steel I-beam rafters 160 are constructed in accordance with the invention with projecting tabs

161 spaced apart along the length thereof at intervals corresponding to the spacing of steel purlins 162, which are attached to the tabs by means of angle brackets 163 and bolts.

Figure 17 illustrates an adaptation in which a steel I-beam column 170 has a projecting tab 171 which is shaped for engagement with a secondary component, for example a floor beam. The tab is formed with a lateral projection 171a to engage with a corresponding aperture in the mating purlin or side-rail, thereby aiding safety and ease of assembly.

Figure 18 illustrates a column 180 with a projecting tab 181 incorporated during fabrication of the column in accordance with the method of the invention, as hereinbefore described. A side-rail 182 is attached by means of a bracket 183 which is bolted to the tab 181 and to which the side-rail 182 is in turn bolted.

Figure 19 illustrates two alternative attachment methods for beams on to a column in building construction. In the upper part of the Figure, the projecting tab 191 , extending through the flange of the I-beam column 190 and welded thereto as hereinbefore described, is provided with three holes 192 there- through, while the web 193 of a floor beam 194 has three corresponding holes 195. The tab 191 locates against the web 193 and between the flanges of the floor beam 194 to permit nuts and bolts to be used to join the beam to the column. Conventionally, additional components, such as double angle web cleats, flexible end plates and fin plates have to be used to achieve the connection. In an alternative conventional arrangement, shoulder bolts on, say, the beam engage in keyholes in an intermediate attachment plate. In the lower part of Figure 19, the beam 196 is shown with shoulder bolts 197 in place on its web. These engage with keyholes 198 formed in the projecting tab 199 from the column 190 to connect the beam to the column without additional fixing operations being required.

Figure 20 shows an alternative arrangement to that of the upper part of Figure 19, and referred to with reference to Figure 17, in which the lateral pro- jection 171a is received in an aperture 200 in the upper flange 201 of the floor beam 202. In this case, the width of the tab 171 (in the vertical direction as shown in the Figure), including the projection 171a, is such as to allow the tab to slide into the space between the upper flange 200 and the lower flange 203 of the beam. When the beam is located on the lateral projection 171a, there is a clearance x between the inner face of the lower flange 203 and the lowermost side of the tab 171 (equal to the length of the projection 171a). The location of the beam on the projection assists assembly, locating the beam in the correct position for the bolts to be inserted and secured with nuts. On shallow beams, the web may be insufficiently sized to achieve the necessary spacing of the bolt holes for attachment to the column. Conventionally, this problem is overcome by welding on extra plates 210 to one or both sides of the beam 211 , as illustrated in Figure 21. Figure 22 illustrates how the same effect can be achieved more precisely by the method of the invention, where the web 221 of the fabricated I-beam 220 is formed with projecting tabs 222 extending through slots in the flanges 223 and 224 and welded thereto.

Claims

1 . A method of fabricating a building constructional element comprising: a) forming an elongate steel web having first and second linear edges and with the first edge having a plurality of tabs projecting outwardly therefrom: b) forming first and second elongate linear flanges corresponding in length to the first and second edges, and forming in said first flange a plurality of apertures corresponding in position and dimensions to the respective tabs on said first edge of the web; c) welding the second flange to the second edge; d) locating the apertures in the first flange over the tabs on the first edge of the web; and e) welding the tabs to the flanges around said apertures.

2. A method according to Claim 1 , wherein each tab projects from the first edge by a distance greater than the thickness of the second flange so that, after welding, the tabs project above the surface of the second flange.

3. A method according to Claim 1 or 2, wherein each flange comprises a steel sheet, and a plurality of said webs are spaced apart across the sheets.

4. A method according to Claim 3, wherein the steel sheets are flat.

5. A method according to Claim 3, wherein the steel sheets are curved or otherwise shaped, and the webs are formed so as to conform with the shapes of the sheets.

6. A method according to any preceding claim, wherein the flanges are uniformly spaced one from the other.

7. A method according to any of Claims 1 to 5, wherein the webs are of varying width.

8. A method according to any preceding claim, wherein after step (a) the or each web is bent or curved along the length thereof.

9. A method of building construction, comprising: constructing a building framework including as floor-supporting beams a plurality of beams having tabs projecting upwardly therefrom; forming metal decking with apertures corresponding in position and dimensions with the projecting tabs; locating the metal decking on to the beams and over the tabs; and pouring concrete on to the decking to form a floor slab.

10. A method of building construction, comprising: constructing a building framework including as floor-supporting beams a plurality of elements fabricated in accordance with the method of Claim 2, the beams being located with the tabs projecting upwardly; forming metal decking with apertures corresponding in position and dimensions with the projecting tabs; locating the metal decking on to the beams and over the tabs; and pouring concrete on to the decking to form a floor slab.

11. A method of building construction according to Claim 9 or 10, comprising forming the tabs with laterally projecting portions to improve anchorage of the concrete to the beams and decking.

12. A method of building construction, comprising forming a plurality of panels by a method according to any of Claims 3, 4 or 5 or any of Claims 6, 7 or 8 when dependent on Claim 3, 4 or 5, and assembling the panels together to form at least a part of a building.

13. A method of building construction, comprising erecting a plurality of columns fabricated in accordance with Claim 2, and attaching flooring and/or roofing beams between the columns by securing the beams to the tabs project- ing from said columns.

14. A method of building construction, comprising erecting a plurality of steel rafters fabricated in accordance with Claim 2, and attaching purlins extending between said rafters to the tabs projecting from the rafters.