GB2465656A

GB2465656A - Composite beam

Info

Publication number: GB2465656A
Application number: GB0917261A
Authority: GB
Inventors: Terence Hoyland
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-10-02
Filing date: 2009-10-02
Publication date: 2010-06-02
Anticipated expiration: 2029-10-02
Also published as: GB2465656B; GB0818014D0; GB0917261D0

Abstract

A composite beam comprises an outer hollow section (4, Fig 1) extruded from recycled polyvinylchloride. Within the outer hollow section are located a plurality of inserts 5, where the inserts extend longitudinally along the length of the hollow section. The inserts include a timber block 10 retained within four pieces of hardened and tempered steel strip 9a, the reinforced timber block located between two support members 9 and sandwiched between upper and lower plywood members 6, 7 respectively. Also included is a composite beam (12, Fig 4) which comprises an outer hollow section extruded from recycled polyvinylchloride, characterised by a plurality of internal lugs (L, Fig 4) serving to locate a fabricated insert (5a, Fig 4) within the outer hollow section. The insert (5a, Fig 4) for this further embodiment includes a two-part plastic component (13, Fig 4) which encapsulates a square section element (14, Fig 4) with a series of steel strips (9a, Fig 4) sandwiched therebetween.

Description

A FABRICATED LIGHTWEIGHT BEAM

Field of the invention

Present conventional methods, within the Building industry and allied trades. Steel beams, Channel sections, and in later years a R H. S (Rolled Hollow Sections) have been introduced. The RH.S., sections although having comparable strength to that of the solid sections, are much lighter in weight and are also produced and available for structural use having higher strength values than their counter parts.

By virtue of the weight factor, in all cases where long lengths of sections are required, lifting equipment is necessary due to the weight of section being used. Having necessitated the use of lifting equipment, for example a Crane. This will increase the costs within the project in hand. The invention seeks to improve upon this, and will have reductions in cost, which will be significant on large projects.

SUMMARY OF THE INVENTION

The invention seeks to provide a fabricated beam structure having comparable strength, to that of steel. This will only be the case in limited structural conditions and It is intended within the invention to use for the main outer case of the beam a re-cycled plastic for example PVC.

By way of the following description and accompanying drawings the invention will now be related.

Fig. I Cross-sectional view of outer case member Fig. 2 Cross-sectional view of insert Fig 3 Diagramatic view of test programme Fig. 4 Cross-sectional view of alternative section Fig. 5 Cross-sectional view Item 4 Fig's land 4 shows the outline cross-section of the beams outer case, and for this description only is an extruded section of a re-cycled PVC plastic. Having a width and depth denoted by the letters W' and D', where W' = 229 millimetres (9inches) and D' 38 millimetres (1.5 inches). The wall thickness is denoted by the letter t' and for this description only is 3.5 millimetres, the overall length is that of 3,962 millimetres (13 feet). In practical terms the overall length will probably be reduced to that of 10 feet for ease of manoeuvrability.

Item S Fig. 2 is the fabricated insert, having in the first part an upper and lower plywood members, items 6 and 7 Fig.2.

Items 8 and 9 Fig.2 are selected pieces of Redwood' and form the side supports of the said insert. The centre section Item 10 consists of a timber block, encapsulated between four pieces of Hardened and tempered steel strip. The said strip Item 9a Fig's 2 and 5 is commercially readily available in various widths and thickness. The sizes of the insert, are represented by the letters w', d' and x'. The thickness of the steel strip Item 9a is 0.5 millimetres and 19 millimetres wide. For this description only the sizes are as follows, w'= 60 millimetres, d'= 31 millimetres and x'=20 millimetres. The entire fabrication of the said insert is retained and held inert, by using a waterproof adhesive in its construction. The 31 millimetres depth of the insert will allow the said insert to be a slide fit within the beam's outer case Item 4 fig. 1 The length of the insert will be equal in length to that of the outer case Item 4 Fig. 1., less the depth of two end cap inserts fitted at either end of the said beam. For reference purposes only the type of end cap inserts that will be used are of the type manufactured from a plastic material or that of a rubber moulding. The reason for fitting end cap inserts is to prevent ingress of foreign particles that will inevitably be present on building and construction sites. The said inserts will also give protection against the weather to the inner inserts within the beam casing.

Finally, Fig. 3 is a diagram showing the Beam Item 4 Fig. I in a horizontal plane with tubular steel supports Item's ii. This was the layout when the said beam in a completed form, was taken to a recognised test centre for load tests to be professionally carried out. The tubular steel members item's ii are a typical tube used on scaffolding structures and found to be adequate for test purposes. The beam item 4, having only one of the fabricated inserts item 6 Fig. 2 positioned in the centre of the of the beam denoted by the centre-line y-y Fig. 1. This was the format for the first test the following results were tabulated and recorded: One Tonne weight was placed in position at the centre of the beam, denoted by the arrow A' Fig. 3, this caused deflection at mid-span and the outer ends of the said beam lifted by 90 millimetres, fl.irtber weights up to the maximum of 1.16kg were added until the beam broke, this figure of 1 tonne 16kg was considered by the testing centre to be quite satisfactory.

A second test was then carried out having two inserts item's 5, fitted within the beam at positions denoted by the letters P'.

With the second test, weights were placed in position at mid-span until a maximum of 1 tonne 860 kg finally caused breakage of the said beam, this result was also considered satisfactory, for the purpose and usage within specified structural conditions.

It may be required in practice to have a tongue and groove facility within the extruded case item 4 Fig's land 4 in both of the short sides (ref. 38 mm.) this will allow interlocking of a plurality of beams. This arrangement would allow flooring to be fitted within building structures and the like.

A thither embodiment of the invention would be to have an alternative extruded section for that of Item 4 fig's 1 and 4, this is shown in sectional detail in Fig. 4 the overall dimensions of W' D' and t' are the same for the section Item 12 Fig. 4 as that of the said extruded section shown in fig. 1. The overall length of 3, 962 millimetres (13 feet) is also the same. There is one significant design difference on the inside profile of the said section Item 12 Fig. 4, whereby a series of Lugs represented by the letter L' which are represented by the dimension I' for both the width and depth. For this description only t' 3.5 millimetres, the said lugs will run longitudinally the full length of the section Item 12 Fig.4. For this description only the said Lugs' will be spaced at the dimensions shown represented by the letters Wi and W2, where W1 86 millimetres and W2=31 millimetres. Item Sa Fig's 4 and is the insert to be used within the section Item 12, Having a dimensional width represented by the letter W3 having a nominal size of 24 millimetres and will be a close slide fit between two selected Lugs' depicted by the letter L'. A detailed description of the said insert Item 5a Fig 5 will be as follows, Item's 13 (TWO) Fig 5 are extruded sections manufactured from a plastics material, and for this description only that of a recycled P V. C. interlocked one to each other by Tongue -like projections and grooves 13a. Encapsulated between the two said sections is a hollow extruded plastics section Item 14, having for this description only internal dimensions of a width represented by the letter x and a depth represented by the letter y fig 4, where x =1 Imillitnetres and y = 12 millimetres. Encapsulated between the outer said sections Items 13 Fig's 4 and 5,and the inner hollow section Item 14, are steel strips Items 9a Fig's 2 and 4, the said steel strip is fI.illy described in detail in the herein before description. The said steel strip is arranged having two vertical members at each side and one horizontal member at the upper and lower positions as shown in Figures 4 and 5. In use dependant on structural design criteria the Beam item fig. 4 will have one or more of the Inserts items 5a Fig's 4 and 5, dependant on the required Load conditions. At the point of filing the description of the Beam Item 4 Fig. 4 Load testing as not been carried out. Therefore it is not possible to compare the two Beams with different design of Inserts and that of the outer extruded sections, however it is considered that the said Beam Item 4 Fig 4 will have comparable strength to that of the Beam Item 4 Fig. 1.

Finally, a plurality of the Beams joined together by tongue and grooves, arranged in a secure vertical position, which would provide a strong and water proof flood barrier.

The insert 5a compared to the insert Item 5 Fig. 2 will be less expensive to produce and will be easier to fabricate to that of its counter part Item 5 Fig. 2.

Claims

CLAIMS1. A fabricated beam having in the first part a main outer hollow section case manufactured from a specified extruded plastics material, in the second part fabricated inserts consisting of upper and lower plywood members encapsulated within two side support members, the centre section consists of a timber block retained within four pieces of hardened and tempered steel strip, dependant on the structural design criteria a plurality of the said inserts can be arranged in position within the inner hollow main outer case and run the entire longitudinal length.
2. A fabricated beam as claimed in claim 1, whereby the said main outer case, can be provided with internal upper and lower lugs arranged at specffied spacing along the longitudinal length, A fabricated two part plastic insert having an encapsulated inner hollow square section *: : encased on all four sides with a specified steel strip, One or more of * : said inserts can be housed and retained in position within the upper and lower said lugs.dl l*, a -
3. A fabricated beam as claimed in claims 1 and 2, whereby end cap inserts are fitted at the two outer ends of the main outer case to a.. t prevent ingress of foreign matter and weather protection.
4. A fabricated beam as claimed in claims 1 and 2, whereby a tongue and groove facility can be provided to the outer sides of the main case and run longitudinally the full length of the said beam.
5. A fabricated beam as claimed in any preceding claim and as herein before described with reference to the accompanying drawings.