WO2005040524A1

WO2005040524A1 - Structural member

Info

Publication number: WO2005040524A1
Application number: PCT/CA2004/001880
Authority: WO
Inventors: André VALOIS; Michel De Blois
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-10-27
Filing date: 2004-10-27
Publication date: 2005-05-06
Anticipated expiration: 2006-04-27

Abstract

The present invention relates to a structural member that comprises an elongated enclosure defining an inner chamber, the elongated enclosure having a longitudinally reinforcing longitudinal web positioned inwardly in the inner chamber; and at least one stiffening member filling the inner chamber and preventing the collapsing of the longitudinal web when stresses are applied to the structural member. It also relates to a method for manufacturing a high strength structural member.

Description

STRUCTURAL MEMBER

CROSS-REFERENCE TO RELATED APPLICATIONS

^• This application claims priority of US provisional patent application 60/514,007 filed on October 27, 2003, the specification of which is hereby incorporated by reference. TECHNICAL FIELD The invention relates to structural members and, more particularly, to structural members, such as building boards used in construction and scaffolding, suited, fo carrying loads.

BACKGROUND ART Structural members are used in building and construction industries to carry relatively heavy loads. They usually consist of load-supporting boards made of wood or metal. These boards must be produced with high quality standards since they carry heavy loads and the potential for serious accidents is substantial. Wood boards are usually simply formed by sawing planks to the desired size. Wood boards however suffer from the adverse affects of the weather and vary quite considerably in their strength, particularly in the case of boards including knots in the wood. Metal boards are advantageous since they are waterproof. However, they are usually made of steel sheets to obtain an adequate stiffness which considerably increase their weight. Moreover, their modulus of resilience is relatively low. Preferably, the structural members for building and construction industries must be relatively light, insensible to weather stresses, and have a high cantilever strength and stiffness.

US Patent No. 6,431,316 describes a scaffold plank including a rectangularly configured main body fabricated from a recycled/recyclable plastic material. The main body is provided with reinforcement webs extending longitudinally and diagonally in the main body. Since the scaffold plank includes diagonal reinforcement members, it cannot be manufactured with low cost manufacturing methods such as extrusion. This increases the manufacturing cost of the plank. Moreover, the mechanical properties of the plank cannot be modified in accordance with the user's specific needs.

DISCLOSURE OF INVENTION

It is an object of the present invention to provide a new structural member suited for use in building and construction industries which has a relatively light weight, a relatively low manufacturing cost, is insensitive to weather stresses, and has adequate mechanical properties.

It is another object of the present invention to provide a structural member wherein the mechanical properties can be increased or decreased according to the specific needs.

It is an object of the present invention to provide a structural member comprising: an elongated enclosure defining an inner chamber, the elongated enclosure having a longitudinally extending reinforcing web positioned inwardly in the inner chamber; and at least one stiffening member inserted in the inner chamber and preventing the collapsing of the reinforcing web when stresses are applied to the structural member, the at least one stiffening member being selected from the group consisting of: a filler material, a solid material layer, a bridging member, and a longitudinal metallic plate.

It is another object of the present invention to provide a structural member comprising: an elongated enclosure defining an inner chamber, the elongated enclosure having a longitudinally extending reinforcing web positioned inwardly in the inner chamber; and at least one stiffening member securely mounted to the enclosure and in the inner chamber and preventing the collapsing of the reinforcing web when stresses are applied to the structural member, the at least one stiffening member being selected from the group consisting of: a filler material, a solid material layer, a bridging member, and a longitudinal metallic plate.

It is another object of the present invention to provide a structural member comprising: an elongated enclosure defining an inner chamber, the elongated enclosure having at least one partition wall longitudinally the inner chamber into at least two side-by-side longitudinal cavities; and at least one stiffening member inserted in the inner chamber and preventing the collapsing of the at least one partition wall when stresses are applied to the structural member, the at least one stiffening member being selected from the group consisting of: .a filler material, a solid material layer, a bridging member, and a longitudinal metallic plate.

It is an object of the present invention to provide a structural member comprising: an elongated enclosure defining an inner chamber, the elongated enclosure having a longitudinally extending reinforcing web positioned inwardly in the inner chamber; and a first and a second stiffening members inserted in the inner chamber and preventing the collapsing of the reinforcing web when stresses are applied to the structural member, the second stiffening member being different from the first stiffening member, the first and the second stiffening members being selected from the group consisting of: a filler material, a solid material layer, a bridging member, and a longitudinal metallic plate.

It is an object of the present invention to provide a building structure comprising at least one structural member. The at least one structural member comprises: an elongated enclosure defining an inner chamber, the elongated enclosure having a longitudinally extending reinforcing web positioned inwardly in the inner chamber; and at least one stiffening member inserted in the inner chamber and preventing the collapsing of the reinforcing web when stresses are applied to the structural member, the at least one stiffening member being selected from the group consisting of: a filler material, a solid material layer, a bridging member, and a longitudinal metallic plate.

It is an object of the present invention to provide a scaffold board comprising at least one structural member. The at least one structural member comprises: an elongated enclosure defining an inner chamber, the elongated enclosure having a longitudinally extending reinforcing web positioned inwardly in the inner chamber; and at least one stiffening member inserted in the inner chamber and preventing the collapsing of the reinforcing web when stresses are applied to the structural member, the at least one stiffening member being selected from the group consisting of: a filler material, a solid material layer, a bridging member, and a longitudinal metallic plate. It is an object of the present invention to provide a structural element, comprising: a one-piece housing haviηg an outer surface, an inner surface, and an internal reinforcing web interconnected with the inner surface; and a first reinforcing member and a second reinforcing member, at least one of the first and second reinforcing members being at least partially juxtaposed to the reinforcing web.

It is another object of the present invention to provide a structural element, comprising: a one-piece housing having an outer surface, an inner surface defining an inner chamber, and an internal reinforcing web interconnected with the inner surface; and a first reinforcing member and a second reinforcing member, the first and second reinforcing members filling the inner chamber.

It is another object of the present invention to provide a . structural element, comprising: a one-piece housing having an outer surface, an inner surface defining an inner chamber, and an internal reinforcing web interconnected with the inner surface; and a first reinforcing member and a second reinforcing member mounted to the housing, at least one of the first and second reinforcing members being at least partially juxtaposed to the reinforcing web.

It is another object of the present invention to provide a building structure comprising at least one structural element. The structural element comprises: a one-piece housing having an outer surface, an inner surface, and an internal reinforcing web interconnected with the inner surface; and a first reinforcing member and a second reinforcing member, at least one of the first and second reinforcing members being at least partially juxtaposed to the reinforcing web.

It is an object of the present invention to provide a method for manufacturing a high strength, structural member comprising: forming a housing defining an inner chamber and having an internal longitudinal web inwardly of the inner chamber; and^' mounting at least one reinforcing member inwardly in the inner chamber, the at least one reinforcing member preventing the collapsing of the longitudinal web when stresses are applied to the structural member, the at least one reinforcing member being selected from the group consisting of: a filler material, a solid material layer, a bridging member, and a longitudinal metallic plate. It is another object of the present invention to provide a method for manufacturing a ^' high strength structural member comprising: extruding a housing defining an inner chamber and having an internal longitudinal web inwardly of the inner chamber; and mounting at least one reinforcing member inwardly in the inner chamber, the at least one reinforcing member preventing the collapsing of the longitudinal web when stresses are applied to the structural member, the at least one reinforcing member being selected from the group consisting of: a filler material, a solid material layer, a bridging member, and a longitudinal metallic plate.

BRIEF DESCRIPTION OF THE DRAWINGS Further features and advantages of the present invention will become apparent from the following detailed description, taken in combination with the appended drawings, in which:

Figure 1 is a perspective view of a housing for a structural member in accordance with an embodiment of the invention;

Figure 2A is a perspective view of the structural member in accordance with an embodiment of the present invention, including an entirely filled reinforcing structure;

Figure 2B is a perspective view of a section of the reinforcing structure of the structural member shown in FIG. 2A;

Figure 3A is a front elevation view of a cross-section of the structural member, including another entirely filled reinforcing structure;

Figure 3B is a front elevation view of a section of the reinforcing structure of the structural member shown in FIG. 3A;

Figure 4 is a front elevation view of the structural member in accordance with another embodiment of the invention, including bridging members as the reinforcing structure;

Figure 5 is a cross-sectional top plan view of the structural member shown in FIG. 4; Figure 6 is a perspective view of the structural member in accordance with a further embodiment of the invention, having a texture on one of its outer face and caps on the transversal ends;

Figure 7 is a perspective view of two interlocked structural members in accordance with an embodiment of the invention;

Figure 8 is a cross-sectional elevation view of a building frame including structural members in accordance with an embodiment of the invention;

Figure 9 is a cross-sectional elevation view of a structural member in accordance with an embodiment of the present invention, not having a parallepipedic shape; and

Figure 10 is a cross-sectional elevation view of a wall including structural members in accordance with an embodiment of the invention.

It will be noted that throughout the appended drawings, like features are identified by like reference numerals.

MODES OF CARRYING OUT THE INVENTION Referring now to the drawings, and more particularly to FIG. 1, it will be seen that a structural member 20, or structural element, includes a housing 22, or an enclosure- having a parallelepipedic shape, similar to a building board, with an inner surface 24 and an outer surface 26. The housing 22 has two opposed longitudinal horizontal walls 28a, 28b separated by two opposed longitudinal vertical walls 30a, 30b. The walls 28a, 28b, 30a, 30b defines an inner chamber 32. The housing 22 is preferably extruded from a thermoset or a thermoplastic plastic which can be a virgin plastic or a recycled plastic. To ensure high mechanical properties, the height of the structural member 20, i.e. the width of the longitudinal vertical wails 30a, 30b, is preferably, greater than two centimeters.

The housing 22 includes an internal longitudinal web 31 located inside the inner chamber 32 to reinforce the housing 22 during extrusion and handling. The web 31 is preferably coextensive with the walls 30a and 30b and ensures that the longitudinal horizontal walls 28a, 28b remain at a predetermined distance from one another. Referring to FIG. 1, there is shown that the internal web 31 includes two partitions 40, 42 extending longitudinally inside the inner chamber 32 parallel to the side walls 30a, 30b between the top and bottom walls 28a and 28b. The partitions 40, 42 and the housing 22 are preferably unitary. For example, they are made of the same material and are extruded simultaneously. However, one skilled in the art will appreciate that the partitions 40, 42 can be securely mounted to the housing 22 with fasteners, adhesive or any manner known by those skilled in the art.

The partitions 40, 42 cooperate with the walls 28a, 28b, 30a, 30b to create three longitudinal cavities 46a, 46b, 46c inside the inner chamber 32. The structural member 22 can include more partitions 40, 42 defining a plurality of longitudinal cavities 46 depending on its width and the predetermined mechanical properties.

Referring to FIG. 2A, there is shown a second embodiment of the present invention wherein like parts are referred to by like reference numerals. The second embodiment includes a structural member 20 having a reinforcing structure 50, or stiffening structure, in the longitudinal cavities 46a, 46b, 46c. The reinforcing structure 50 includes a plurality of layers 54, 56 disposed longitudinally inside the longitudinal cavities 46a, 46b, 46c. The layers 54, 56 entirely fill the cavities 46a, 46b, 46c for providing support to the web 31 to prevent the same from collapsing when stresses are applied to the structural member 20. Depending on the predetermined mechanical properties of the structural member 20, layers 54, 56 of various material can be used. The width of each layer 54, 56 depends also on the predetermined mechanical properties.

In FIG. 2A, seven layers 54, 56 of two different materials are disposed in the inner chamber 32. Against and along each longitudinal vertical wall 30a, 30b in the longitudinal cavities 46a, 46c, a layer 54a of a stiff material is disposed. The stiff material can be, for example, wood, plywood, veneer, ferrous and non-ferrous metals, composite materials such as glass fiber, carbon, Kevlar®, polyetheretherketone (PEEK), natural cement, light cement, polymeric cement, or any other material known to one skilled in the art. Two layers 54b of the same material are disposed against the partitions 40, 42 in the longitudinal cavity 46b. The layers 54a, 54b are preferably securely mounted to the housing 22. The layers 54a, 54b can be mounted to the inner surface 24 of the housing 22 and/or the partitions 40, 42. On FIG. 2A, the layers 54a, 54b are mounted with an adhesive which is suitable for both materials, i.e. the plastic of the partitions 40, 42 and the stiff material of the layers 54a, 54b. The adhesive ensures adhesive integrity of the structural member 20. Urethane foam can also be used as an adhesive. Fasteners (not shown) ^•can also be used to mount the layers 54a, 54b to the housing 22 and the partitions 40, 42.

The layers 56, which are made of another suitable material, are disposed inside the remaining portions of the longitudinal cavities 46a, 46b, 46c. The layers 56 are . preferably made of a lightweight material or a filler material such as wood, cardboard, foam such as polyurethane or polystyrene foam, plastic, bulk material such as recycled rubber powder or wood powder maintained in a solid rigid form with an adhesive or a resin, concrete, pultrusion, and any other material known to one skilled in the art. The layers 56 are fixedly mounted against the juxtaposed layers 54a, 54b and/or the partitions 40, 42. Referring again to FIG. 2A, it will be seen that the layers 56 are secured with an appropriate adhesive, which can differ from the adhesive. Fasteners (not shown) can also be used to mount the layers 56 to the housing 22, the partitions 40, 42, and the layers 54a, 54b. The structural member 20 can also be conceived without adhesiv.es or fasteners, however inferior mechanical properties are expected.

Referring now to FIGS. 3A and 3B, it will be seen that by inserting a thin plate 66 of metal or another highly stiff material juxtaposed against at least one longitudinal vertical face 70 of the layers 54a, 54b, it is possible to increase the cantilever strength without increasing considerably the weight of the structural member 20. For example, the layers 54a, 54b cart be made of wood while the layers 56 can be made of foam. To reinforce the structural member 20, each longitudinal vertical face 70 of the wood layers 54a can be plated with a thin steel plate 66. To increase the mechanical properties of the structural member 22, a thin plate 66 of the highly stiff material can also be juxtaposed to the longitudinal vertical face of the wood layers 54b and/or. the foam layers 56. To reinforce the . structural member 20, the transversal vertical faces 72 and the longitudinal horizontal faces 74 of the layers 54a can be covered with ohe-piece rigid strip 76 as shown on FIG. 2B. The layers 54b and 56 can also be covered with strips 76. The strips 76 can be made of metal, fiber glass, PET, pultrusion, or any other highly stiff material. The strips 76 can be fastened, glued or mounted to the layers 54a, 54b, 56 by any technique known to one skilled in the art. When stresses are applied to the structural member 20, the layers 54a, 54b, 56 bend and the strips 76 reinforce the structural member 20 by being in tension.

Therefore, using the above-mentioned reinforcing techniques, cheaper materials with lower mechanical properties can be used for the layers 54a, 54b, 56 and the structural member 20 can still have high mechanical properties. Moreover, by using different combination of layers and stiffening members in the reinforcing structure 50, the mechanical properties and the weight of the structural member 20 can be modified as desired by the user. It is appreciated that sections of the inner cavity 32 can remain empty in the structural member 20 (as shown in FIG. 1 ).

Referring to FIGS. 4 and 5, there is another embodiment of the present invention, wherein like parts are referred to by like reference numerals. It can be appreciated that the reinforcing structure 50 can also include a plurality of bridging members 80 (here in the form of cross-braces) disposed along the longitudinal cavities 46a, 46b, 46c and extending crosswise therein from one corner to an opposed one thereof. The bridging members 80 have a X-shape configuration and can be made of a material such as a metal, preferably a lightweight metal (aluminum, magnesium), wood, plywood, composite materials such . as glass fiber, carbon, Kevlar®, or polyetheretherketone (PEEK), plastic, and any other material known to one skilled the art. The bridging members 80 are fixedly mounted to the partitions 40, 42 and/or to the inner surface 24 of the housing 22. The bridging members 80 are mounted to the structural members 20 with an appropriate adhesive, fasteners or by any other technique known to one skilled in the art.

It is well understood that the structural members 20 can include any possible combination for the reinforcing structure 50. For example, the reinforcing structure 50 can be only one layer of a single material inserted in one_. of the cavities 46a, 46b, 46c, only foam to provide a lightweight structural member 20, reinforced or not layers of several materials, and the like.

Referring to FIG. 6, and as illustrated with respect to the first embodiment of the present invention, it will be seen that the transversal ends 84 of the various above- described structural members 20 can be encapsulated to prevent infiltration in the inner chamber 32. This can be achieved by providing caps 85 preferably made of metal, plastic, rubber, wood or any other appropriate material. The caps 86 can be securely engaged over the transversal ends 84 with a clip mechanism (not shown) that prevents their released, they can also be glued, welded, bolted or mounted by any other technique known to one skilled in the art. The caps 86 can also be conceived such as to provide shock absorbance for the structural member 20.

It is also possible to apply a fluid covering material to the transversal ends 84. When dried, this covering material provides sealing caps 86 on the transversal ends of the structural member 20.

Also, in the embodiment illustrated in FIG. 6, the outer surface 26 of the housing 22 has a texture 90 to give nonslip properties to the structural member 20. The texture 90 can be obtained with an abrasive (not shown) applied to the outer surface 26 or with a brush buffer. The texture 90 can also be obtained from a modified surface such as a surface covered with glue, a combination of glue and filler, adhesive paper, powder, etc.

The housing 22 can include an interlocking system 92 allowing to assemble at least two structural members 20 side-by-side as shown in FIG. 7. The interlocking system 92 of FIG. 7 includes a groove 94, a female member, along one longitudinal vertical wall 30a and a tongue 96, a male member, along the other longitudinal vertical wall 30b. To assemble two structural members 20 side-by-side, the tongue 96 of the first, structural member 20a is inserted inside the groove 94 of the second structural member 20b. Referring back to FIG. 2A, it will be seen that, for each structural member 20, the interlocking system 92 can include a dovetail assembly with a groove 94 shaped like the tail of a dove for holding a male member 96 having a substantially trapezoidal shape in a mating engagement. The male and female members 94, 96 are positioned on a respective longitudinal vertical wall 30a, 30b. To assemble two structural members 20 side-by-side, the tongue 96 of the first structural member 20a is slidably longitudinally inserted inside the groove 94 of the second structural member 20b. To prevent easy release of the interlocked structural members 20a, 20b, the groove 94 and the tongue 96 can be toothed 98 as shown on FIG. 3A or the groove 94 and the tongue 96 have a dovetail shape as shown on FIG. 2A. Thus, the only way to released the two structural members 20a, 20b is to slide longitudinally the one structural members 20a relative to the adjacent structural member 20b. It can also have any other shape that preferably prevents easy release of both structural members 20.

Referring to FIG. 8, it will be seen that the structural members 20 can be used for building a housing structure 106. For example, referring to FIG. 10, it will be seen that a wall 110 built with the structural members 20 can include two structural members 20c having several layers of a stiff material as the reinforcing structure 50 and a plurality of structural members 20d having bridging members 80 as the reinforcing structure 50. The structural members 20c, having higher mechanical properties, are disposed at each end of the wall 110 and are separated by the structural members 20d, having a lower weight. The structural members 20c, 20d are interlocked together with an interlocking system 92 such as the ones described hereinabove. To reinforce the wall 110, it is possible to replace some or all the structural members 20d with the structural members 20c. The mechanical properties of the structural members 20c, 20d can be varied as desired by modifying the reinforcing structure 50 enclosed within the inner chamber 32 or by modifying their dimensions.

Even if the structural members 20 are mounted horizontally to form the wall 110 on FIG. 8, one skilled in the art will appreciate that they can be mounted vertically.

It is possible to store liquids inside the structural members 20d, i.e. including bridging members 80 as the reinforcing structure 50 or any other reinforcing structure 50 including empty sections. Liquids can thus be stored inside the walls 110 and the roof 136 (FIG. 8). For example, it is possible to recover rain water that falls on the roof 136 through a gutter system 138. The recovered rain water is sent through pipes 139 inside the longitudinal cavities 46a, 46b, 46c of the structural members 20d and stored therein. When water is required for various needs, water is drawn from the longitudinal cavities 46a, 46b, 46c with a pipe system.

Referring to FIG. 9, it is also be seen that structural members 20 are not limited a parallelepipedic shape. It _. is possible to create various shapes according to the specific needs such as an exterior wall corners 144 with the interlocking system 92 including one groove 94 and one tongue 96, as a female and a male members.

The structural member 20 can be used as scaffold boards. The structural member 20 can also be used for building fences, patios, traffic signs, oversized destination sign, railroad tracks, loading pallets, etc.

The structural member 20 is lightweight comparatively to a similar size wooden board, weather resistant, has a good bending strength, and can be commercially manufacture a relatively low cost. By a careful design, the overall strength of the structural member 20 can be substantially greater than that of a similar size wooden board.

The mechanical properties and the weight of the structural member can be increased or decreased in accordance with the specific needs. The design and the type of materials used for the reinforcing structure can be adapted to correspond to these needs while keeping the same housing. By using an adequate reinforcing structure 50, structural members 20 having a high cantilever strength, stiffness, and modulus of resilience.

The embodiments of the invention described above are intended to be exemplary only. For example, the housing 22 can include rails (not shown) on the inner surface 24 of one or both longitudinal horizontal walls 28a, 28b to guide the insertion of the reinforcing structure 50. The rails are preferably extruded simultaneously with the housing 22. However, they can also be mounted to the housing 22 with fasteners, adhesive or any other appropriate technique. Moreover, the interlocking system can differ from the ones disclosed hereinabove.

The scope of the invention is therefore intended to be limited solely by the scope of the appended claims.

Claims

1. A structural member comprising: an elongated enclosure defining an inner chamber, said elongated enclosure having a longitudinally extending reinforcing web positioned inwardly in said inner chamber; and at least one stiffening member inserted in said inner chamber and preventing the collapsing of said reinforcing web when stresses are applied to said structural member, said at least one stiffening member being selected from the group consisting of: a filler material, a solid material layer,, a bridging member, and a longitudinal metallic plate.

2. A structural member as claimed in claim 1 , wherein said at least one stiffening member is securely mounted to said enclosure.

3. A structural member as claimed in one of claims 1 and 2, wherein said longitudinally reinforcing web.. comprises at least one partition wall dividing longitudinally said inner chamber into at least two side-by-side longitudinal cavities.

4. A structural member as claimed in any one of claims 1 to 3, wherein said structural member comprises a first stiffening member and a second stiffening member different from said first stiffening member.

5. A structural member as claimed in any one of claim 1 to 4, wherein said at least one stiffening member is made from a material selected from the group consisting of wood, plywood, veneer, ferrous and non-ferrous metals, composite materials such as glass fiber, carbon, Kevlar®, and polyetheretherketone (PEEK), cardboard, foam such as polyurethane or polystyrene foam, plastic, bulk material such as recycled rubber powder or wood powder maintained in an assembly with an adhesive or a resin, concrete, and pultrusion.

6. A structural member as claimed in any one of claims 1 to 5, comprising at least one stiffening member encircled with a strip, said strip being in tension when said structural member is bent.

7. A structural member as claimed in any one of claims 1 to 6, wherein said enclosure is formed in a single-piece extrusion.

8. A structural member as claimed in any one of claims 1 to 7, wherein said enclosure is extruded from one of a virgin plastic and a recycled plastic.

9. A building structure comprising at least one structural member as claimed in one of claims 1 to 8.

10. A scaffold board comprising at least one structural member as claimed in one of claims 1 to 8.

11. A structural element, comprising: a one-piece housing having an outer surface, an inner surface, and an internal reinforcing web interconnected with said inner surface; and a first reinforcing member and a second reinforcing member, at least one of said first and second reinforcing members being at least partially juxtaposed to said reinforcing web.

12. A structural element as claimed in claim 11, wherein said inner surface defines an inner chamber and said first and second reinforcing members fill said inner chamber.

13. A structural element as claimed in one of claims 11 and 12, wherein said at least one reinforcing member is mounted to said one-piece housing.

14. A structural element as claimed in any one of claims 11 to 13, wherein said internal reinforcing web comprises at least one partition wall defining at least two longitudinal cavities in said housing.

15. A structural element as claimed in any one of claims 11 to 14, wherein at least one said first and second reinforcing members comprises at least one layer of a solid material disposed along at least one of said cavities.

16. A structural element as claimed in claim 15, wherein said first and second reinforcing members are made from a material selected from the group consisting of wood, plywood, veneer, ferrous and non-ferrous metals, composite materials such as glass fiber, carbon, Kevlar®, and polyetheretherketone (PEEK), cardboard, foam such as polyurethane or polystyrene foam, plastic, bulk material such as recycled rubber powder or wood powder maintained in an assembly with an adhesive or a resin, concrete, and pultrusion.

17. A structural element as claimed in claim 15, wherein at least one of said first and second reinforcing members- is encircled with a strip, said strip being in tension when said structural element is bent.

18. A structural element as claimed in any one of claims 11 to 17, wherein said housing is extruded from one of a virgin plastic and a recycled plastic.

19. A building structure comprising at least one structural element as claimed in one of claims 11 to 18.

20. A method for manufacturing a high strength structural member comprising: forming a housing defining an inner chamber and having an internal longitudinal web inwardly of said inner chamber; and mounting at least one reinforcing member inwardly in said inner chamber, said at least one reinforcing member preventing . the collapsing of said longitudinal web when stresses are applied to said structural member, said at least one reinforcing member being selected from the group consisting of: a filler material, a solid material layer, a bridging member, and a longitudinal metallic plate.

21. A method as claimed in claim 20, comprising forming at least one partition wall in said inner chamber for dividing said inner chamber in at least two cavities.

22. A method as claimed in claim 20, comprising extruding said housing simultaneously with said internal longitudinal web.

23. A method as claimed in . any one of claims 20 to 22, comprising mounting at least one layer of a solid material in said inner chamber.

24. A method as claimed in any one of claims 20 to 23, comprising partially filling said inner chamber with a filler material selected from the group consisting of: a foam material, a bulk material, powder, and concrete.