EP0827560A1

EP0827560A1 - A structural section

Info

Publication number: EP0827560A1
Application number: EP97902492A
Authority: EP
Inventors: Trevor Challender
Original assignee: Challender Trevor
Current assignee: Steel Technology And Design Ltd
Priority date: 1996-02-05
Filing date: 1997-02-05
Publication date: 1998-03-11
Also published as: AU1612497A; WO1997029255A1

Abstract

A structural section has first and second planar members (21, 22, 36, 37) spaced one from the other by an infill panel (30, 38, 40) attached along its edges to each of the first and second members. The infill panel is of a corrugated, preferably pressed steel, formation interconnected between the first and second members along the whole or part of their length. Conveniently, edges of the infill panel will lie along or about the longitudinal central axis (38A) of the planar members and may be of a single thickness. Conveniently, two corrugated structures (41, 42) are connectable back to back to define the infill panel and may be welded to the first and second members along the whole of the length of the infill panel or alternatively only in the region of the web portions (60) of the corrugated panel on either side of the structural section. In one alternative section, the first member (21) is an elongate planar member and the second member (22) has a central portion (23) lying parallel with the first member and has an outer portion (24, 25) at each end, respectively, of the central portion which extends in the longitudinal direction of the central portion but outwardly relative to the first member to define haunches.

Description

A STRUCTURAL SECTION

This invention relates to a structural load bearing beam structure.

It is known to provide a beam or similar load- bearing structure which is manufactured conveniently from a hot rolled section having an I-shaped cross section. The hot rolled metal bar having an I-shaped cross section has a very strong construction which can withstand heavy loads. However, because the metal bar is solid rolled steel it is extremely heavy and difficult to handle.

In one type of load-bearing structure, a triangular shaped haunch can be welded to the ends of the beam. This assists in the location and stability of the beam when used in the eaves region of the roof of the building.

Disadvantageously, manufacturing costs are increased by the addition of haunches not only for the cost of welding a haunch onto the hod rolled beam section but also the additional cost of material of the haunch area.

There are disclosures in the art of structural members comprising flanges with corrugated infill panels. In most of these the structure has been an attempt to provide an alternative to a box beam structure. Thus in many cases the corrugations of the infill panel have "peaks" which approach the edges of the flanges. The constructions also are difficult to weld. There seems to be little evidence that most of these suggested constructions have ever been manufactured in practice. It is an object of the invention to overcome these particular disadvantages and provide a structural load section in which the above disadvantages are substantially eliminated.

According to the present invention there is provided a structural section comprising first and second spaced planar members, and an infill panel attached to and extending between the opposed major surfaces of the first and second members, wherein the infill panel is of a corrugated formation interconnected between the first and second members along the whole or part of their length.

The edges of the infill panel, preferably of pressed steel metal, will normally be along or about the longitudinal central axis of the planar members.

In one preferred embodiment of the invention the infill panel is of a single thickness corrugated structure. Conveniently, two corrugated structures are connectable back to back to define another form of infill panel which because of the use of the two corrugated sections has stronger load bearing properties than the structure having a single corrugation infill panel construction. Whilst parts of the corrugations contact each other in this dual infill panel construction, one alternative construction requires two corrugated infill panels to be spaced one from the other so that electrical wiring or other services can be inserted through the space.

In another alternative construction in accordance with the present construction the first and second planar members include an outwardly directed flange extending transversely from each of the elongate side edges of an outermost major surface of each plate, thereby to define a substantially rectangular generally U-shaped cross section with its respective plate. Conveniently, in use, the first or uppermost plate can support a wooden beam and the second or lowermost can be provided with a bottom cover to define an elongate hollow channel within which electrical wires or other services can be located.

The first and second members can conveniently have a form in which the second member is parallel to the first member only over a central portion thereof and then tapers outwardly at opposed ends to define haunches . The infill panel is correspondingly shaped so that it extends into the haunch areas in contact with the first and second members.

A beam can therefore be made from two elongate longitudinally extending parts arranged to overlie one another with the top part being a flat elongate planar plate and the other part having a similar but shortened central planar plate portion with an outwardly tapered part at each end of that shortened plate portion to define a haunch area. The space between the outer plate parts is filled with a pressed infill panel which is pre-shaped to have a periphery which conforms to the construction of the outer elongate plates so that the top edge is straight and the bottom edge, for example, is largest at its outermost extremity in the longitudinal direction thereof and gradually reduces in size to the center plate which lies parallel to the first mentioned elongate plate portion.

Preferably, the infill panels have cross section which can be curvilinear, rectangular, trapezoidal or triangular. In any event, the corrugated infill panel may be of a regular, or irregular pressed panel . The thickness of the plate from which the corrugated panel is formed can be varied depending on the desired structural strength of the final beam.

Moreover, the thickness of the corrugated panel either in terms of the thickness of the plate from which it is formed or the depth of the corrugations or both may vary along the length of the beam depending on the desired strength of the beam at various points.

In the present invention the relationship between the thickness of the web sheeting to the corrugating structure to the thickness of the flanges is such as to ensure maximum strength being derived from the flange elements without increasing the weight of the structure by an undue thickness of the sheeting used to make the corrugated infill panel.

Relationships can be developed which characterize the correlation of these three features to give maximum effectiveness to the final structural member.

Particularly important is the width of the infill panel in relationship to the width of the flanges. By selecting a relatively narrow width for the corrugated infill panel in relation to the flanges one can ensure that there will be no interference with holes for conventional bolt groups in the flanges and at the end of the structural member including any plates mounted on the structural member for attachment to other structures .

Thus by correct choice of dimensional characteristics, conventional structural bolting groups can be positioned outside the profile of the panel in a manner similar to a conventional straight web. Positioning of bolt group holes is determined by various standards so that there is relatively little freedom to change the location of bolt holes in a structural member. If the width of the corrugated panel is too great there is bound to be interference with such holes and bolts placed in such holes when assembling the construction.

It is also important that the surfaces of the flanges against which rests the edge of the corrugated panel are substantially planar. Particularly they should not have inwards turned edges or curvature. If the flange edge is turned inwardly, for example, by a portion along the edge of the flange which is vertical to the plane of the flange inwardly then access to the corrugated panel would be difficult for the purpose of welding. Similarly if the flange is curved then it may be difficult to ensure that the edge of the corrugation lies evenly along the surface of the flange to provide simple welding and subsequent strength.

As previously mentioned it is possible to vary the flanges and an important aspect of this invention is the selection of differing flanges in contrast to the convention hot rolled I-beam. The flanges can provide a simple means of incorporating channels along the structural member. However, even with flat flanges one can have flanges of different width providing a structural member which is much more flexible in use than the conventional I-beam. Particularly by properly configuring either or both flanges to include portions which are vertical to the essential plane of the flange and extending away from the side to which the infill panel is attached one may in addition to providing extra functionality to the flange e.g. as a channel provide greater strength to the flange by reason of the portion particularly the portion at right angles to the flange and must be able to reduce the thickness i.e. the weight of the flange.

Thus the flange may provide a channelled cross section or be a simple flat flange but of different dimensions for each flange or provide other variation for either or both flanges.

However, the two flange sections may or may not run parallel to each other. The beams may vary in depth from one end to the other.

However, each top and bottom flange section though straight in the plane of the flange may be curved in plan {ie. plan of flange) .

While it might be possible to attach the infill panel to the opposed first and second members by welding along the whole of the length of the infill member, partial welding of portions of the infill member has been found to provide a structure which still has the structural advantages of one in which the welding is continuous but the structure can be fabricated much more quickly and yet give a structure as satisfactory as one in which continuous welding is employed. The welding can be effected from either side of the infill panel along parts of the infill panel or by "stitching" along the whole of the periphery of the panel adjacent to the first and second planar members.

In one preferred embodiment, the partial (or stitch) welds are applied along the web elements which are in plane with the beam structure and even more preferably are on one side only of the web at each location. It has been found that omitting welding along diagonal (or other elements not parallel to the plane of ~~.~_M*C 97/29255

the beam structure) does not affect the strength of the structure as the non-planar elements do not substantially affect the resistance to shear forces between planar members and panel members. By omitting welding of these non-planar portions efficient production is facilitated without affecting structural performance and integrity.

The partial or stitch welding particularly in the preferred embodiment along the planar portions of the panel has the following advantage:

(a) Bending capacity of the structure is maximised:

(b) Welding is facilitated particularly for automatic fabrications .

The edge of the infill panel adjacent to a planar member can be filled by applying a glue or sealant and this can be applied along the entire length of the panel edge, or only along those portions in which no welding has taken place. The glue or sealant can be any conventional structural sealant, for example an epoxy product. It is desirable that such glue or sealant is strongly adherent to steel materials or other materials used for forming the structural member and preferably is moisture resistant so as to prevent entry of moisture into the unwelded portions so as to resist corrosion.

Conveniently the structural section of the present invention is formed of steel, but may be of plastics or wood.

Embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings, in which:- Fig. 1 is a side elevational view of a conventional beam of a hot rolled section including a haunch welded on at each opposed end thereof;

Fig. 2 is a side elevational view of one form of a structural section including a pressed infill panel with integral haunches;

Fig. 3 is a side elevational view of a structural section in accordance with the present invention;

Fig. 4 is a cross sectional view along the line A-A of Fig. 3;

Fig. 5 is a cross sectional view along the line B-B of Fig. 3;

Fig. 6 is a cross sectional view along a line corresponding to A-A of Fig. 3 but shows an alternative form of cross section of the infill panel;

Fig. 7 is a cross sectional view along a line corresponding to section B-B of Fig. 3 but of yet a further alternative construction in which in the Figure the upper and lower plates in Fig. 7 are of a generally U-shaped configuration;

Fig. 8 is a cross-sectional view similar to the view in Fig. 4 with the numbering of the elements being the same;

Fig. 9 is a cross-sectional view similar to the view of Fig. 6 with the numbering being the same;

Fig. 10 illustrates diagrammatically the location of welded portions along straight portions of the panel members;

Figs, lla-e illustrate variants in the "flange" plates; and

Figs. 12a-f illustrate further variants in the flange plates .

Referring now specifically to Fig. 1 there is illustrated a conventional structural section or fabricated load-bearing rafter, having a hot rolled section 1 and includes a first or upper elongate planar flange plate 2 with its major planar surfaces 3,4 extending in Fig. 1 in a substantially horizontal direction, and a similar lower or second planar plate 5 having elongate major surfaces 6, 7 extending in the same direction and parallel to major planar surfaces 3, 4 thereof.

An integral central web 12 extends between the plates 2, 5 to give the hot rolled section 1 a substantially I-shaped cross section to the fabricated rafter. In the region of each opposed end 8, 9 of the rafter structure there is provided a haunch 10,11 respectively, welded to the hot rolled section 1.

One disadvantage of the prior art load-bearing structure referred to above is that such metal bars are relatively expensive to manufacture in providing the additional haunch portions and welding them in place separately. Moreover, the haunch portions add to the weight of the overall structure.

Referring to Fig. 2, there is shown a structural section according to the present invention in the form of a fabricated rafter 20 having an external shape, in side view, which is substantially identical to the side view illustrated in Fig. 1 but in this instance the rafter of Fig. 2 has a single elongate flat planar first or uppermost flange plate 21 and a second or bottom flange plate 22 which is in three portions, the first of which is a central portion 23 of an elongate planar flange plate form which lies parallel to and extends in the same direction as the first flange plate 21. Two flange plate portions 24, 25 are themselves of a similar construction to the central portion 23 and are welded to the central portion at each, respectively, opposed end 26, 27 of the central flange plate portion 23. However, the portions 24 and 25 could be formed by bending the ends of an elongate plate. The flange plate portions 24, 25 extend downwardly and outwardly in the longitudinal direction of the rafter to define a haunch portion 28, 29 integrally formed with the rafter. A corrugated infill panel 30 is cut to a predetermined shape and located in the space between first and second flange plates 21 and 22 being joined thereto preferably by welding.

Turning now to Figs. 3 through 7, there are disclosed various forms of structural sections in accordance with the present invention.

A first embodiment of a structural section in accordance with the present invention is shown in Figs. 3 through 5, where there is illustrated a structural section 35 having a substantially I-shaped cross section including first (uppermost) and second (lowermost) elongate flange plates 36, 37 which are of a substantially rectangular cross section and which extend parallel one relative to the other in an overlying spaced parallel relationship. A corrugated infill pressed panel 38 is welded between the flange plates 36, along a longitudinal center line 38A to define the cross sectional structure as shown in Fig. 5 by viewing along the section line B-B in the direction shown in Fig. 3.

Fig. 4 illustrates a sectional view along the section line A-A in Fig. 3 and shows the infill panel 38 to be of a corrugated structure in which the thickness of the material from which the corrugations 39 are pressed is substantially less than the thickness in the vertical direction in Fig. 5 of the flange plates 36, 37.

Such a construction is relatively cheap to produce. The structural section is of a relatively light weight construction and is therefore more easily handled than the prior art rafter disclosed herein in Fig. 1.

With the particular structure of the pressed infill panel 8 shown in Figs. 3 through 5, the structural section can be used for light load bearing locations .

Should a heavier load bearing beam be required then this can be produced in the same manner as disclosed with reference to Fig. 3 but having an infill panel 40 which has the construction which is shown in Fig. 6 and which is a sectional view taken along a line corresponding to the section A-A in Fig. 3. Here, there are illustrated two corrugated sections 41, 42 which are connected back to back so as to provide, extending in a vertical direction, channels 43 between spaced corrugations 44, 45 and double thickness walls 46 where the corrugations contact one another. The corrugations 45 which contact one another can be welded together in this contact area. The additional strength provided by this double corrugated infill panel 40 ensures that the beam constructed in this manner will be able to handle much greater loads than the previously described structural sections of Figs. 3 to 5 at minimum cost.

Fig. 7 illustrates a further alternative embodiment of a structural section in accordance with the present invention having upper and lower elongate parallel flange plates 50, 51 each of which is provided along each of its opposed elongate edges 52, 53 with a transversely outwardly extending flange 54, 55, respectively. The elongate channel formed between flange plate 50 and flanges 52, 53 can in use support a wooden roof strut for example. A similar such construction is provided in respect of lower flange plate 51 but in this instance flanges 54', 55' extend outwardly in an opposite direction to the direction in which the flanges 54 and 55 of flange 50 extend from opposed outer edges 52 ' , 53' .

A bottom cover 56 is provided with a similar cross section to that of flange plate 51 for clipping onto, or being welded to, the outer extremities of the flange plates 54 ' , 55 ' so as to define therebetween a channel 57 in which electrical wires or other services can be located when the structural section is used in the roof of a building, for example. A suitable infill panel 58 is pressed into the space between the flange plates 50, 51. Otherwise, the embodiment of Fig. 7 takes the same features as the embodiment of Figs . 3 or 5 or Fig. 6.

A similar construction to that described for Figs 6 and 7 can be provided with a spacing 47 between the two corrugated sections in the transverse direction indicated by arrow A in Fig. 6, so that electrical wiring or tubing for central heating or normal water or gas supplies can be located. Apertures can also be provided through the flange panels to provide access to channels 47 in Fig. 6 between the corrugations through which wiring or piping as just described can be passed.

As described with reference to Figs. 4 and 6, the structural elements are constructed by joining the panel members 38, 41 and 42 to the flange plates. Joining is effected by partial or "stitch" welding along the portions marked A in each of the drawings (Figs. 8 and 9) •

As shown in Figure 10 the welds 60 are short portions separated from each other and only along those portions 61 of the panel members which are plane (i.e. parallel to) the plane of the beams.

The portions 45 between the "peaks and troughs" of the corrugated material is left unwelded. This welding can be effected by welding from one side of the panel member.

A sealant is then applied along the whole length of the edge between the panel member and each flange plate, although one could apply sealant only on those portions in which there is no welding. The sealant is a conventional epoxy curable sealant which is water resistant.

The number of points at which stitch welding is effected must be sufficient to provide integrity for the final structure, but otherwise should be the minimum possible to achieve the necessary jointing of the panel member and flange.

In the alternative embodiment of the invention which can include partial ("stitch") welding the structures of the invention can be constructed of planar members (flanges) which are of various types.

Thus the planar member flanges can be of different types joined by the web and can be any combination of:

a) Flat sections b) Hold rolled sections

These will typically be rolled channel box sections or joint sections but may include heavier sections to increase structural stability both vertically and laterally. c) Cold rolled sections

These will be designed to suit the user requirements and to provide the necessary structural effect.

They will include:

i) Channel section tops to receive fixing timbers ii) Channel section bottoms to receive services. Some sections may receive covers to conceal services or form "ducts" . iii) Top hat or similar type sections to allow the use of proprietary fixings for connection of other members.

The welding pattern will typically be a single side weld along the outer side of the flat section of the corrugation profile but may include the configuration to suit the specific user requirement.

Thus in the drawings of Figs, lla-d the structures have planar members which are pressed sections with the web portions being pressed sections of trapezoidal or curvilinear profile. In Figs. 11a, b, c and e a lid or cover 56.

In Figs 12a-e the planar members are hot rolled sections of channel or I beam cross-section. This illustrates the flexibility of the present structure as compared to conventional beams.

Fig. 12f shows top and bottom planar members which are hot rolled flats or pressed sections with an asymmetric cross-section for composite use (eg. in floor or roof constructions) . Various embodiments of the structural section in accordance with the present invention have been described with a regular shaped pressed infill panel but in these embodiments such infill panel may be of an irregular pressed shape, for example as far as the corrugations are concerned, the depth of the corrugations could be varied along the beam or the thickness of the plate from which the panel is formed could vary along the beam. Moreover, the infill panel corrugations can be curvilinear, rectangular, trapezoidal or triangular.

Claims

CLAIMS : 16

1. A structural section comprising first and second spaced planar members (21,22,36,37), and an infill panel (30,38) attached to and extending between the opposed major surfaces of the first and second members, wherein the infill panel (30,38) is of a corrugated formation interconnected between the first and second members along the whole or part of their length.

2. A structural section as claimed in claim 1, wherein the edges of the infill panel (30,38) lie along or about the longitudinal central axis of the planar members (21,22,36,37) .

3. A structural section as claimed in claim 1 or claim 2, wherein the infill panel (30,38) is of a single thickness corrugated structure (38) .

4. A structural section as claimed in claim 1 or claim 2, wherein the infill panel (30,38,40) comprises two corrugated structures (41,42) connected back to back.

5. A structural section as claimed in any one of the preceding claims, wherein the infill panel (40) comprises two corrugated infill panels spaced one from the other for receiving electrical wiring or other services therebetween.

6. A structural section as claimed in any one of the preceding claims, wherein the first and second planar members

(50,51) include an outwardly directed flange (52,53) extending transversely from each of the elongate side edges of an outer most major surface of each plate, thereby to define a substantially rectangular generally U shaped cross-section with its respective plate (50) .

7. A structural section as claimed in claim 6, wherein the U shaped cross-section associated with the outermost major surface of one (51) of the first and second members is provided with a cover (56) to define an elongate, hollow channel (57) therein.

8. A structural section as claimed in any one of the preceding claims, wherein the second member (22) is parallel to the first member over a central portion (23) thereof and tapers outwardly at opposed ends (24,25) to define haunches.

9. A structural section as claimed in claim 8, wherein the infill panel (30) is correspondingly shaped so that it extends into the haunch areas in contact with the first and second members (21,22) .

10. A structural section as claimed in any one of the preceding claims, wherein the infill panels (30,38,40) have a cross-section which is curvilinear, rectangular, trapezoidal or triangular.

11. A structural section as claimed in any one of the preceding claims, wherein the corrugated infill panel (30,38,40) is a regular or irregular pressed panel.

12. A structural section as claimed in any one of the preceding claims, wherein the thickness of the plate from which the corrugated panel is formed is selected independence upon a desired structural strength of the final beam.

13. A structural section as claimed in claim 12, wherein the thickness of the corrugated panel, the depth of the corrugations, or both are variable along the length of the beam independence upon the desired strength of the beam at various points. 14. A structural section as claimed in any one of the preceding claims, wherein the width of the corrugated infill panel (30,38,40) relative to the width of the flange

(21,22,50,51) is narrow for avoiding interference with holes for conventional bolt groups in the flanges.

15. A structural section as claimed in any one of the preceding claims, wherein the surface of the first and second members (21,22,50,51) against which rests the edge of the corrugated panel are substantially planar.

16. A structural section as claimed in any one of the preceding claims, wherein the width of the first and second members is unequal.

17. A structural section as claimed in any one of the preceding claims, wherein the infill panel (30,38,40) is welded to each respective first or second member along the whole of the length of the infill member.

18. A structural section as claimed in any one of claims 1 to 16, wherein the infill panels (30,38,40) are welded to the first and second members only along the web elements on one side (60) only of the web at each location.

19. A structural section as claimed in any one of the preceding claims, wherein the edge of an infill panel (30,38,40) adjacent to a planar member is filled by applying glue or sealant along the entire length of the panel edge, or only along those portions in which no welding has taken place.

20. A structural section as claimed in claim 19, wherein the glue or sealant is an epoxy resin. AMENDED CLAIMS

[received by the International Bureau on 23 July 1997 (23.07.97); original claim I amended; remaining claims unchanged (1 page)] i. A structural section comprising first and second spaced planar members (21,22,36,37) including longitudinally extending opposed major surfaces thereof, and an infill panel (30,38) attached to and extending between the said opposed major surfaces to define a section of an I-shaped configuration, wherein the infill panel (30,38) is of a corrugated formation interconnected between the first and second members along the whole or part of their length, with each corrugation peak being interconnected with the first and second members on the side thereof nearest lateral elongate edge of the first and second members, respectively.

3. A structural section as claimed in claim 1 or claim 2, wherein the infill panel (30,38) is of a single thickness corrugated structure (38).

6. A structural section as claimed in any one of the preceding claims, wherein the first and second planar members (50,51) include an outwardly directed flange (52,53) extending transversely from each of the elongate side edges of an outer most major surface of each plate, thereby to define a substantially rectangular generally U shaped cross-section with its respective plate (50) .

7. A structural section as claimed in claim 6, wherein