GB2519812A

GB2519812A - Improvements in structural members and methods relating thereto

Info

Publication number: GB2519812A
Application number: GB1319273.7A
Authority: GB
Inventors: Lee Edward Jackson; Michael Ian Rowell
Original assignee: Travis Perkins PLC
Current assignee: Travis Perkins PLC
Priority date: 2013-10-31
Filing date: 2013-10-31
Publication date: 2015-05-06
Also published as: GB201319273D0

Abstract

A structural member is provided which comprises an elongated planar web and at least one elongated flange. The web comprises a series of openings to allow services such as ducting, pipes or cables to pass therethrough. The cut ends of the member are reinforced by means of a reinforcing device which is located against the web and/or flange(s).

Description

IMPROVEMENTS IN STRUCTURAL MEMBERS AND METHODS RELATING THERETO

The invention relates to the field of structural members for use in building construction, and to methods of cutting and reinforcing such members. More particularly, but not exclusively, the invention relates to timber joists, for example I-joists, but other materials may be usable.

Structural members such as beams and joists (these terms are hereafter used interchangeably) play an important part in the construction of building structures. They are commonly used as supports for floors, ceilings, roofs or walls. Often, such beams will comprise of an elongate vertical web, and at least one elongate flange (usually two flanges) along the edge of the web. These beams may also be used to support further cross-beams which extend perpendicular to the beam.

In construction it is often advantageous for beams to be provided with holes through the web to allow access to services, such as pipework, ducts or cables. In the case of timber joists this can be achieved by drilling or sawing a hole through the web. It has been understood, hitherto, that such holes will introduce a point of structural weakness in the joist, and as such, holes have only been introduced away from the ends of joists as these are the points most likely to be placed under a compressive load. This has made it difficult to use joists with pre-formed or pre-drilled holes because joists are generally manufactured in standard lengths and then cut to size as required.

Cutting to a desired length will often mean that a joist is cut through or near a hole, and therefore outside prevailing guidelines for hole position.

Contrary to prevailing guidance, this invention seeks to address the problem of supplying pre-drilled joists which can be cut to size after manufacture according to the length required, even where this causes the cut end of the joist to be at or near a hole. Solving this problem has significant advantages in that there is no need to carry out drilling, cutting or other hole forming on site.

It is known to have metal I-beams with web holes large enough for services to be run through. Such I-beams, however, cannot be readily cut to size using carpentry tools.

According to one aspect of the present invention there is provided a structural beam, capable of being sawn to a desired length, comprising an elongate planar web and at least one elongate flange extending along the web, the web having a multiplicity of holes for allowing ducting, pipes and/or cables to pass therethrough; and beam reinforcing means at at least one end thereof for reinforcing the beam. The beam reinforcing means comprise at least one reinforcing element secured to the beam.

Preferably, the beam may comprise a web and two parallel flanges. The two parallel flanges may have the same cross-section, or the two parallel flanges may have different cross-sections. Alternatively the beam may comprise a web and one flange.

Preferably, the reinforcing element comprises a planar plate secured to the beam, located against the web and the flange or flanges. Alternatively, the reinforcing element may comprise a planar plate secured to the beam, located against the flange or flanges.

Furthermore, the reinforcing elements described above may also comprise a support for a horizontal bracing piece, or noggin, projecting perpendicularfrom the beam The web and flanges may be provided of any suitable material such as solid sawn timber, engineered timber products, engineered wood panel products or wood-plastic composites.

Different components of the beam may be composed of different materials. It will be recognised by those skilled in the art that such an invention may also be constructed of other materials which might be easily sawn such as plastics.

The reinforcing element may be made of a similar material to components of the beam itself, or indeed may be made of a different material, including wood products, plastics, metals or composite materials.

Another aspect of the present invention is a method of cutting and reinforcing a structural beam, the beam comprising an elongate planar web and at least one elongate flange extending along the web, the web having a multiplicity of holes for allowing ducting, pipes and/or cables to pass therethrough; the steps comprising cutting the structural beam to a desired length, and securing a reinforcing element to the beam at at least the cut end of the beam.

Said reinforcing element may comprise a planar plate located against the web and the flange or flanges. Alternatively the reinforcing element may comprise a planar plate located against the flange or flanges.

The reinforcing element may be secured by means of an adhesive. Alternatively, the reinforcing element may be secured by means of one or more suitable mechanical fastener, such as nails, screws, staples or the like.

A reinforcing element may be secured to one end of the beam, or a reinforcing element secured to each end of the beam.

Furthermore, the reinforcing element may support a member extending perpendicular to the beam. Additionally, one or more such reinforcing elements may be further introduced to the beam along its length so that a plurality of members extending perpendicular to the beam may be supported.

Brief Description of the Drawings

By way of example, embodiments of a structural beam according to the invention will now be described with reference to the accompanying drawings: Figure 1 shows end-on views of various beam configurations; where Figure 1(a) shows an I-beam, Figure 1(b) shows a 1-beam and Figure 1(c) shows an asymmetric I-beam.

Figure 2 is a side view of embodiments of structural beams according to the invention; where Figure 2(a) shows an I-beam and Figure 2(b) shows a T-beam.

Figure 3 is a perspective view of the end of the beam of Figure 2(a) to which a reinforcing device is secured. Figure 3(a) shows a reinforcing device which lies against the face of the web and abuts the inner faces of the flanges and Figure 3(b) shows an alternative reinforcing device which is affixed to the side faces of the flanges.

Detailed Description

Figure 1 shows end views of three common joist configurations. Figure 1(a) shows a typical two-flange I-joist 10 with a web 11 secured toflanges 12 and 13. The materials of the web 11 and flanges 12 and 13 may be different and varied, but are such that the I-joist 10 can be readily cut to length using normal saws or other tools capable of cutting timber.

The web 11 is typically made of wood panel product, such as plywood or a re-constituted timber panel product such as oriented strand board (OSB), chipboard orfibreboard. The web may also be made of wood/plastic composites or of plastics material. The web and flanges may be made of similar or dissimilar materials and these may also be sawn timber or an engineered timber product such as laminate veneer lumber (LVL), laminated strand lumber (LSL), parallel strand lumber (PSL) or glued laminate timber (glulam).

The flanges 12 and 13 are secured to the web 11 either by use of adhesive or mechanical fasteners such as nails, screws, staples or the like.

Figure 1(b) shows an alternative T-joist profile with a web 15 and a single flange 16 secured to the web 15 as described previously with reference to Figure 1(a). Figure 1(c) shows a further beam profile where a web 18 is secured to a lower flange 19 and upper flange 20, the lower flange 19 being of larger cross section than the upper flange 20. The flanges 19 and 20 are secured to the web 18 as described with reference to Figure 1(a).

Figure 2(a) is a side view of the I-joist of Figure 1(a). As can be seen readily, the web 11 has holes 14 at regular spacing and will be noted that the I-joist 10 is cut at its ends through holes 14. The holes 14 are geneially pie-drilled. Extensive testing has established that the load bearing characteristics of the I-joist 10 with holes 14 are satisfactory compared with the load bearing characteristics of an un-drilled I-joist of similar profile and dimension but end reinforcement, described later with reference to Figure 3, is necessary at cut-ends where the end of I-joist is at or nearaholel4.

Typically, the joist 10 may have a height of 180 -600 mm, and the width of the flanges 12, 13 be 38 -97 mm The size of the hole may vary depending on the size of the joist, typically from -514 mm. The joists would normally be manufactured to standard lengths, between 1 m and 20 m. The above dimensions are given by way of example only, and joists of other dimensions are within the scope of the invention.

Figure 2(b) is a side view of the T-joist of Figure 1(b); apart from that difference, comments made above with reference to Figure 2(a) apply to the T-joist of Figure 2(b).

The purpose of the holes 14 are to provide access for commonly required services such as pipework, ducting or cables to be run through the joist. It is advantageous for the holes to be made in the web 11 or 15 or 18 at the point of manufacture so that the joist arrives pie-drilled and can then be cut to a desired length. Drilling can take place on site within guidelines for hole spacing and size. The holes 14 are round and provide greater structural integrity than square or rectangular holes. Other shaped holes are within the scope of the invention as defined in the claims.

The holes 14 also enable the I-joist of T-joist to be lighter than a solid joist, making it easier to handle, and also reduces wind resistance relative to a solid joist.

Ends of joists such as these will have to bear high loading and the loading is typically compressive as well as having a torsional element. Because the pre-drilled joists are cut to length after they have been manufactured, it is quite possible that the joist end will be at an opening, as shown in Figure 2(a) of Figure 2(b). Thus, as shown in Figure 3, reinforcement of the cut end of the joist is provided and will now be described.

Figures 3(a) and 3(b) show a cut end of the beam 10 of Figure 1(a) and Figure 2(a) where reinforcing elements have been secured in place.

Figure 3(a) shows two rectangular reinforcement plates 25, 26 secured either side of the web 11 and fitting between the inside surfaces of the flanges 12 and 13. The geometry of the plates 25 and 26 is such that the plates 25 and 26 engage with the inner surfaces of the flanges 12, 13 so that a compressive load can be taken by the cut beam end. In Figure 3(a) and Figure 3(b) the end of the joist 10 cuts through a hole 14. The plates 25 and 26 can be constructed of any suitable material, for example metal or metal alloy, timber, engineered wood panel products such as plywood, reconstituted timber panels such as OSB, chipboard or fibreboard, plastics or a wood-plastic composite. The plates 25 and 26 can be secured in place by adhesive or typical fastenings such as screws, nails, staples or the like.

Figure 3(b) shows an alternative reinforcing element in the form of plates 30 and 31 surface fixed to the flanges 12 and 13. The plates 30 and 31 can be of any of the materials listed in relation to the plates 25 and 26 and securement can similarly be by adhesive or other fixings such as screws, nails, staples or the like.

The assembly sequence is, in this particular example, for a pre-drilled I-joist or T-joist to be manufactured to a standard length, after which the joist is measured and cut to a desired length according to requirements from site. The cut end of the joist is then reinforced as described in relation to Figure 3(a) or Figure 3(b). The other, uncut end of the joist may also be reinforced in the same way. At site, the cut, reinforced joist can then be positioned and fixed in place.

Alternatively, the pre-drilled joist might be cut to the desired length with one end cut at a location avoiding a hole 14, and the other end cut at a location at or near a hole 14. The joist might then be reinforced only at the end cut near a hole 14, or might be reinforced at both ends. The joist might also be cut such that both ends are cut at a location at or near a hole 14, as illustrated in Fig. 2(a) or 2(b), and both ends reinforced.

The reinforcing plates 25, 26, 30 and 31 may have a support bracket or hanger (not shown) to support a noggin to extend perpendicularly to the joist axis. The joists can also carry hangers for noggins in the usual way. Reinforcing plates 25, 26, 30 or 31 can also be added on site to reinforce joists intermediate their ends where particular loading requirements are to be met.

The preferred embodiments described above are by way of example; the scope of the invention is defined in the appended claims, and modification to the example may be made within the scope of the claims.

Claims

Claims 1. A structural beam, capable of being sawn to a desired length, comprising: an elongate planar web and at least one elongate flange extending along the web, the web having a multiplicity of holes for allowing ducting, pipes and/or cables to pass therethrough; and beam reinforcing means at at least one end thereof for reinforcing the beam, the beam reinforcing means comprising: at least one reinforcing element secured to the beam.
2. A beam as claimed in claim 1 comprising a web and two parallel flanges.
3. A beam as claimed in claim 2 wherein the two parallel flanges have the same cross-section.
4. A beam as claimed in claim 2 wherein the two parallel flanges are of different cross-section.
5. A beam as claimed in claim 1 comprising a web and one flange.
6. A beam as claimed in any one of claims 1 -5, wherein the reinforcing element comprises a planar plate located against the face of the web and against the flange or flanges.
7. A beam as claimed in any of claims 1 -5, wherein the reinforcing element comprises a planar plate located against the flange or flanges.
8. A beam as claimed in any one of claims 1 -7, wherein the beam comprises beam reinforcing means at both ends of the beam
9. A beam as claimed in any one of claims 1 -8, wherein at least one reinforcing element further comprises a support for a member projecting perpendicular from the beam.
10. A beam as claimed in any of claims 1 -9, wherein the web and/or flange components comprise sawn timber.
11. A beam as claimed in any of claims 1 -9, wherein the web and/or flange components comprise an engineered timber product such as laminate vaneer lumber, laminated strand lumber, parallel strand lumber or glued laminate timber.
12. A beam as claimed in any of claims 1 -9, wherein the web and/or flange components comprise a wood panel product such as plywood, or reconstituted timber panel product such as oriented strand board, chipboard or fibre-board.
13. A beam as claimed in any of claims 1 -9, wherein the web and/or flange components comprise a wood-plastic composite.
14. A beam as claimed in any of claims 1 -9, wherein the web and/or flange components comprise a plastic.
15. A beam as claimed in any of claims 1 -14, wherein the reinforcing means comprises sawn timber.
16. A beam as claimed in any of claims 1 -14, wherein the reinforcing means comprises an engineered timber product such as laminate vaneer lumber, laminated strand lumber, parallel strand lumber or glued laminate timber.
17. A beam as claimed in any of claims 1 -14, wherein the reinforcing means comprises a wood panel product such as plywood, chipboard, fibre-board or reconstituted timber panel.
18. A beam as claimed in any of claims 1 -14, wherein the reinforcing means comprises a
19. A beam as claimed in any of claims 1 -14, wherein the reinforcing means comprises a plastic.
20. A beam as claimed in any of claims 1 -14, wherein the reinforcing means comprises a metal.
21. A method of cutting and reinforcing a structural beam, the beam comprising an elongate planar web and at least one elongate flange extending along the web, the web having a multiplicity of holes for allowing ducting, pipes and/or cables to pass therethrough; the steps comprising: cufting the structural beam to a desired length, and securing a reinforcing element to the beam at at least the cut end of the beam.
22. A method of claim 21, where the reinforcing element comprises a planar plate located against the web and the flange or flanges.
23. A method of claim 21, where the reinforcing element comprises a planar plate located against the flange or flanges.
24. A method of claims 22 or 23 where the reinfoicing element is secuied by means of an adhesive.
25. A method of claims 22 or 23 where the reinforcing element is secured by means of one or more mechanical fastenei.
26. A method of any of claims 21 -25, where a reinforcing element is secured to one end of the cut beam.
27. A method of any of claims 21 -25, where a reinfoicing element is secuied to each end of the cut beam.
28. A method of any of claims 21 -27, where at least one reinforcing element supports a member projecting perpendicular to the beam.
29. A method of claim 28, wheie one oi more additional ieinfoicing elements are intioduced to the beam along its length away from the cut ends so that a plurality of members projecting perpendicular to the beam are supported.
30. A structural beam substantially as hereinbefore described with reference to and as shown in figures 1(a), 2(a) and 3(a), or as modified by figures 3(b) or in figuies 1(b) or 1(c) of the accompanying drawings.
31. A method of cutting and reinforcing a structuial beam substantially as hereinbefore described with reference to the accompanying drawings.