GB2591128A - Propping system and prop sections for use therein - Google Patents

Abstract

A prop section 100 for use in a propping system, comprises a pair of elongate channel sections 110, 120, each channel section 110, 120 includes a planar rear major portion 110R, 120R and a pair of minor flange portions 110, 120F extending outwardly from opposite sides of the rear major portion 110R, 120R. The elongate channel sections 110, 120 are oriented back-to-back relative to each other with the planar rear major portion 110R, 120R of one of the channel sections 110, 120 facing the planar rear major portion 110R, 120R of the other of the channel sections 110, 120. The respective pairs of minor flange portions 110, 120F extend outwardly from their respective rear portions 110R, 120R in opposite outward directions. A pair of transverse end members 130A, 130B are located at respective longitudinal ends of the pair of back-to-back elongate channel sections 110, 120 and are attached thereto so as to unite the pair of channel sections together to form the prop section 110. A kit of parts for forming the prop section is also included.

Description

PROPPING SYSTEM AND PROP SECTIONS FOR USE THEREIN

TECHNICAL FIELD

This invention relates to a propping system and to prop sections for use therein. More particularly, though not exclusively, the invention relates to novel prop sections which are employable in conjunction with other components of an overall propping system. Such a propping system, and the new prop sections which form part thereof, are usable in a variety of building, civil engineering and industrial scenarios where structural support apparatus is required.

BACKGROUND OF THE INVENTION AND PRIOR ART

In many building, civil engineering and industrial operations some kind of structural support system or equipment is often required for temporarily supporting part or all of the structure being constructed or worked on in a stable and safe manner. Such structural support systems typically include props, which are usually designed to be of adjustable lengths, which are used to securely brace or support the relevant structure (or part thereof) while the necessary work or construction is carried out. Typical applications of such propping systems include for example the supporting of buildings or parts of buildings during construction, refurbishment, repair, reconstruction or demolition, as well as various civil engineering scenarios such as in the construction or repair of roads, bridges and railways.

There are many known designs of prop. Some are based on a simple elongate cylindrical steel tube (which often is telescopically slidable yet lockable relative to another like cylindrical tube which together form a telescopic prop of variable length). Others are based on an elongate steel (or other strong metal or metal alloy) channel section forming a specially cross-sectioned post, column or beam, which may be attachable to one or more other like channel section posts, columns or beams in order to suit particular dimensional requirements of a particular propping scenario. Most known examples of such props are designed to have attached at at least one of their ends one or more other components of an overall propping system, such as a prop foot plate or ground support, a jack (for varying the length/height of the main body of the prop), or one or more beams, struts or other support members.

For economy of material and in order to optimise their load-bearing capability versus weight ratios, some modern prop designs based on channel-sectioned posts, columns or beams of formed steel (or other metal/alloy) with specially shaped cross-sections often have their various webs and/or flanges provided with one or more series of appropriately placed apertures or holes in order to enhance their strength/weight ratio even further.

However, the above known designs of props for use in propping systems all tend to have limited load-bearing capability, stiffness and strength/weight ratios. Many known prop designs also have limited versatility and applicability to different propping requirements or environments, especially when propping distances/heights vary, and in terms of the props' interconnectability and ability to be readily attached to other components of an overall propping system.

It is therefore a primary object of the present invention to ameliorate or at least partially solve at least some of the shortcomings of known props for use in propping systems, and to provide new prop sections which improve on known props' characteristics of load-bearing capability, stiffness and strength/weight ratio, as well as providing enhanced interconnectability and ability to be readily attached to other components of an overall propping system.

SUMMARY OF THE INVENTION

Accordingly, in a first aspect the present invention provides a prop section for use in a propping system, comprising: a pair of elongate channel sections, each channel section comprising a generally at least partially substantially planar rear major portion and a pair of minor flange portions extending outwardly from opposite sides of the rear major portion, wherein the elongate channel sections are oriented back-to-back relative to each other with the rear major portion of one of the channel sections facing the rear major portion of the other of the channel sections and the respective pairs of minor flange portions extending outwardly from their respective rear portions in generally opposite outward directions; and a pair of transverse end members bounding respective longitudinal ends of the pair of back-to-back elongate channel sections and being attached thereto so as to unite the pair of channel sections together to form the prop section.

In many practical embodiments of the prop sections of the invention, the elongate length of the pair of channel sections defines a longitudinal axis or longitudinal length of the prop section. Accordingly, in many practical embodiments of the invention it is the transverse (i.e. perpendicular with respect to the prop section's longitudinal axis or length) cross-sectional shapes of the pair of elongate channel sections (optionally together with any additional optional structural elements of the respective prop section as defined further below) being a primary contributing factor to the overall advantageous properties of enhanced strength/weight ratio and stiffness of the prop sections according to embodiments of the invention.

In some embodiments, in each of the channel sections, the height or width of the respective rear major portion (i.e. the transverse height/width of the rear major portion in the plane of the material thereof) may be greater than, e.g. at least about 2 or 3 or 4 or 5 or perhaps even greater than 5 times, the corresponding width (i.e. the transverse width in the plane of the material thereof) of each of the respective minor flange portions extending outwardly therefrom. In this manner, the general overall form of each of the channel sections in cross-section may thus be approximately rectangular, rather than square.

In some embodiments, in each of the channel sections, the respective rear major portion may comprise a substantially planar central portion, and extending to either side of the central portion a pair of lateral side portions also substantially planar but each being stepped rearwardly relative to the central portion and joined thereto by a respective one of a pair of ramp or shoulder or bridging portions. The transverse height/width (i.e. in the plane of the material thereof) of the respective planar central portion may be several times, e.g. from about 3 or 4 or 5 times up to about 7 or 8 or 9 or 10 or 12 or 15 or perhaps even greater than 15 times, the corresponding transverse height/width (i.e. in the plane of the material thereof) of each of the lateral side portions (which pair of lateral side portions may themselves be of substantially the same transverse height/width). This shape/configuration of the respective rear major portion may further help to contribute to the overall enhanced strength/weight ratio and stiffness of the prop sections according to embodiments of the invention.

In some practical embodiments of prop sections according to the invention, the respective rear major portions, or at least the substantially planar central portions thereof, of the pair of channel sections may be configured and/or arranged such that they are spaced apart by a gap of a suitable distance for accommodating therewithin a threaded rod or bar of a jack or jacking assembly that may be used in conjunction with the prop section as part of the overall propping system.

In some embodiments, in each of the channel sections, each of the minor flange portions in each respective pair thereof extending outwardly from opposite sides of the rear major portion may so extend outwardly therefrom at an angle of substantially about 90 degrees relative to the general plane of the respective rear major portion.

In some embodiments, in each of the channel sections, each respective one of the minor flange portions in each pair thereof extending outwardly from opposite sides of the respective rear major portion may comprise at least a substantially planar primary flange portion. Such a respective planar primary flange portion of each respective minor flange portion may be oriented substantially perpendicularly with respect to the planar central portion of the respective rear major portion of the respective channel section.

In some such embodiments, in each of the channel sections, each respective one of the minor flange portions in each pair thereof may comprise a respective terminal secondary flange portion extending from the respective primary flange portion and terminating the said respective minor flange portion. Each respective terminal secondary flange portion may extend substantially perpendicularly with respect to the respective primary flange portion of the respective minor flange portion, especially such that the pair of terminal secondary flange portions of the pair of minor flange portions of each channel section extend and point towards one another in substantially opposite directions, especially in substantially a common plane in space.

Furthermore, each respective terminal secondary flange portion of the respective minor flange portion may be of a relatively short transverse height/width, e.g. no greater than the corresponding transverse height/width (especially in substantially parallel planes in space) of the corresponding respective lateral side portion of the respective rear major portion of the respective channel section. Again, this shape/configuration of the respective terminal secondary portions of the respective minor flange portions may yet further help to contribute to the overall enhanced strength/weight ratio and stiffness of the prop sections according to embodiments of the invention.

In many practical embodiments of prop sections according to the invention, each of the pair of transverse end members bounding and being attached to the respective longitudinal ends of the pair of back-to-back elongate channel sections may comprise, or be in the form of, a plate or sheet or other substantially flat or planar member. Each such end plate may be attached to the respective longitudinal ends of the channel sections by any suitable attachment means, especially for example by welding (e.g. fillet welding or spot welding) or alternatively by means of suitable mechanical attachment or fixing means, e.g. bolts, screws, nuts, rivets, etc, or alternatively a suitable adhesive. Thus, each end plate or other end member may bound and be attached to the respective longitudinal ends of the channel sections in such a way as to securely unite the pair of channel sections together so as to form a strong and substantially rigid dual-channel-sectioned prop section whose stiffness and ability to Wthstand twisting or other deformation under load may be significantly enhanced in comparison vvith known prop designs of comparable weight-per-unitlo ngitudi na l-length.

In practical terms in many embodiments, each of the end plates or other end members of a given prop section may additionally provide a means by which the respective prop section may be interconnected, especially end-to-end, to another prop section via a relevant one of its own end plates/members, e.g. by any suitable interconnection means (such as bolt(s), nut(s), screw(s), etc). For the purpose of such interconnecting of the prop section to another prop section, each end plate or other end member may be provided with a suitable arrangement of holes, apertures, slots or other interconnection-enabling means. In this manner plural prop sections according to embodiments of the invention may if desired be used in a modular fashion, to construct compound linear prop sections of any appropriate desired overall longitudinal lengths or even compound prop section arrangements in a desired non-linear configuration.

Alternatively or additionally, each of the end plates or other end members of a given prop section may further provide a site or means by which the respective prop section may be mounted on or connected to one or more other components of an overall propping system, such as a jack, a jack base assembly, a prop foot plate or ground support, or one or more beams, struts or other support members of the propping system. For the purpose of such mounting or connecting of the prop section to one or more other components of the propping system, each end plate or other end member may be provided with a suitable arrangement of holes, apertures slots or other mounting-or connection-enabling means. In some practical embodiment forms, each end plate may further be provided with an appropriately dimensioned through-hole or aperture (especially centrally located therein) for accommodating and allowing passage therethrough of a threaded rod or bar of a jack or jacking assembly that may be used in conjunction with the prop section as part of the overall propping system.

In some embodiment forms of prop section according to the invention, the prop section may further comprise, mounted or attached internally of and between the pair of channel sections, one or more bracing members. The or each bracing member may be mounted or attached, e.g. by welding (e.g. fillet welding or spot welding), brazing or the like, or by a suitable adhesive, between the respective rear major portions of the respective channel sections between the interior-facing walls thereof. The or each bracing member may thus be dimensioned such that it spans and substantially fills or matches the size of the gap between the respective rear major portions of the respective channel sections.

The or each bracing member may itself comprise an elongate generally C-shaped channel section, especially a C-shaped channel section whose minor flange portions are the portions which provide the necessary sites of mounting/attachment to the main channel sections of the prop section. The longitudinal length of the C-shaped channel section forming the or each bracing member may substantially match or be approximately equal to the transverse height/width (i.e. in the plane of the material thereof) of the rear major portions of the respective main channel sections of the prop section. However, it may be possible for other, alternative, cross-sectional shapes or profiles of bracing members to be employed in other embodiments.

Any suitable number of bracing members may be provided in any given embodiment prop section, depending for example on the longitudinal length of the prop section and the degree of stiffness and strength it is desired to have. In particular, when a given prop section has a longitudinal length beyond a certain distance (e.g. beyond about 0.5 metres in some typical practical embodiment forms), there may be provided one or more, or indeed perhaps a plurality of, such bracing members mounted/attached internally within the gap between the rear walls of the respective channel sections. Where only one such bracing member is provided, it may be located substantially midway (i.e. approx. halfway) along the longitudinal length of the prop section. On the other hand, where a plurality of such bracing members are provided, they may be located in a regular, uniform spaced apart fashion at equidistant intervals (e.g. typically at 0.5 metre intervals) along the longitudinal length of the prop section.

However, in embodiments where one or more stiffener elements are provided as defined below, then it may be desirable for the longitudinal position of the or each of the bracing members on the interior sides of the channel sections to be such as to lie intermediate the longitudinal positions of (especially midway between) respective ones of the stiffener elements located to the exterior sides of the respective channel section (especially where plural such stiffener elements are provided on each channel section) or intermediate the longitudinal positions of (especially midway between) a stiffener element and either one of or each of the end members (especially where only one stiffener element is provided on each channel section). Thus, in embodiments where both one or more internal bracing members and one or more external stiffener elements are provided on opposite faces/walls of a given channel section, then the relevant bracing member(s) and stiffener element(s) may desirably be out-of-register with respect to each other on either side of the relevant channel section, so that on both sides of the relevant channel section no two bracing members and stiffener elements are at the same or approximately the same longitudinal position along the length of the relevant channel section and they are longitudinally spaced apart relative to each other on those opposite sides of the relevant channel section.

Once again, this overall distribution and positioning, and optionally also shape/configuration, of the one or more bracing members may yet further help to contribute to the overall enhanced strength/weight ratio and stiffness of the prop sections according to these particular embodiments of the invention.

In some embodiment forms of prop section according to the invention, each of the channel sections may have externally mounted thereon or attached thereto one or more stiffener elements. Such stiffener element(s) may be mounted on or attached to the relevant externally-facing wall of the relevant channel section -especially to at least the externally-facing wall of the central planar portion of the rear major portion thereof and optionally also to the respective planar primary flange portions of the respective minor flange portions thereof -by any suitable means, such as welding (e.g. fillet welding or spot welding), brazing or suchlike, or alternatively by a suitable adhesive.

The provision of such one or more stiffener elements on each channel section may be necessary or desirable in certain embodiment prop sections depending on the overall longitudinal length of the prop section in question. In particular, when a given prop section has a longitudinal length beyond a certain distance (e.g. beyond about 0.5 metres in some typical practical embodiment forms), there may be provided one or more, or indeed perhaps a plurality of, such stiffener elements mounted on or attached to each respective channel section. Where only one such stiffener element is provided on each channel section, it may be located substantially midway (i.e. approx. halfway) along the longitudinal length of the prop section. On the other hand, where a plurality of such stiffener elements are provided on each channel section, they may be located in a regular, uniform spaced apart fashion at equidistant intervals (e.g. typically at 0.5 metre intervals) along the longitudinal length of the prop section.

However, in embodiments where one or more bracing members are provided as defined above, then it may be desirable for the longitudinal position of the or each of the stiffener elements on the exterior sides of the channel sections to be such as to lie intermediate the longitudinal positions of (especially midway between) respective ones of the bracing members located to the interior sides of the channel sections (especially where plural such bracing members are provided) or intermediate the longitudinal positions of (especially midway between) a bracing member and either one of or each of the end members (especially where only one bracing member is provided). Thus, in embodiments where both one or more external stiffener elements and one or more internal bracing members are provided on opposite faces/walls of a given channel section, then the relevant stiffener element(s) and bracing member(s) may desirably be out-of-register with respect to each other on either side of the relevant channel section, so that on both sides of the relevant channel section no two stiffener elements and bracing members are at the same or approximately the same longitudinal position along the length of the relevant channel section and they are longitudinally spaced apart relative to each other on those opposite sides of the relevant channel section.

The or each stiffener element may comprise any suitably shaped/configured fillet insert, web, plate or flange, especially one which is generally flat and rectangular in shape. Furthermore, the or each such stiffener element may be so mounted or attached to each channel section that its general plane is oriented transversely and perpendicularly to the longitudinal length of the prop section.

Once again, this overall distribution and positioning, and shape/configuration, of the stiffener element(s) may yet further help to contribute to the overall enhanced strength/weight ratio and stiffness of the prop sections according to these particular embodiments of the invention.

In practising various embodiments of the invention, the pair of channel sections and the end members, and optionally also the bracing member(s) and stiffener element(s) Cif present), may be formed of any suitable strong and rigid sheet, plate or web material, especially a metal or metal alloy. Alternatively certain synthetic plastics materials may be used instead, if their physical properties make them so suitable. Examples of suitable metals include various steels, such as those steels commercially available under the designations S700MC, i.e. hot-rolled, high-strength low-alloy steels e.g. of the "Strenx" (trade mark) series from SSAB AB or of the "Ympress" (trade mark) series from Tata Steel.

The thickness and/or grade of the plate/web material used to form the components of any given embodiment prop section may be selected for example depending on the overall degree of stiffness, strength/weight ratio and thus duty rating (e.g. "light" duty, "medium" duty, or "heavy" duty) that the given prop section is designed to exhibit. By way of example, plate/sheet/web thicknesses of from about 1 or 1.5 mm up to about 4 or 5 or 8 or 10 or 12 mm (e.g. typically around 2 to 3 mm) may be suitable in many practical embodiments for at least the respective elongate channel sections. Also by way of example, it may be in some instances be possible for any bracing members and/or stiffener elements to be formed from similar thicknesses of plate/sheet/web material or alternatively perhaps slightly smaller thicknesses, e.g. from about 0.5 or 1 or 1.2 or 1.5 mm up to about 3 or 4 or 5 or 6 or 7 or 8 mm.

The relevant component parts of the relevant embodiment prop sections may be manufactured form the relevant materials by any suitable industrial technique, such as forming, drawing, deep-dravving, pressing, moulding, or other suitable shaping process.

Specific forming methods, apparatuses and processing conditions that may be employed will be well-known and readily available to persons skilled in the art.

In some embodiment forms of prop section according to the invention, each of the channel sections may be provided or formed with one or more, especially a plurality of holes or apertures or slots/slits therein and extending through the material thereof, in order to further enhance the strength and stiffness of the plate/sheet/web material. The holes/apertures may be provided in either or both of the rear major portions of the respective channel sections and/or in each of the minor flange portions extending from the respective rear major portion thereof.

Any suitable pattern or array or arrangement of one or more series of such holes or apertures may be employed, such as one or more linear rows or series. The holes/apertures in each series or row may be generally regularly spaced and uniformly distributed longitudinally along and/or transversely across the relevant wall(s) of the relevant channel section (or, especially, of the relevant rear major portion and/or minor flange portions thereof).

In general terms, prop sections according to embodiments of the invention have a unique and novel cross-sectional shape and construction, based primarily on the pair of back-to-back mounted and united (via at least the end members) generally C-shaped channel sections, especially those known in the art generally as "sigma sections", which gives such prop sections particularly desirable and enhanced stiffness and strength-to-weight ratios.

Furthermore, in some embodiments that unique and novel construction may be further contributed to and the resultant physical properties of stiffness and strength-to-weight ratios further enhanced by the optional presence -if desired or necessary -of the one or more internal bracing members and/or one or more external stiffener elements. The particular cross-sectional shapes and constructions of embodiment prop sections according to the invention also lend them particularly well to being used in a modular fashion, enabling them to be interconnect together Wth one another and/or to be connected or attached to one or more other components of an overall propping system, e.g. a jack or jack base assembly.

Thus, prop sections according to various embodiments of the invention may be of any desired longitudinal lengths. Moreover, the presence and, if they are present, the number(s) and longitudinal distribution(s) and relative positioning(s) of any bracing member(s) and/or stiffener element(s) that may optionally be included in any embodiment prop section may be dictated by the overall longitudinal length that the embodiment prop section has.

In order to enhance the modular nature of prop sections in accordance with the invention, such embodiment prop sections which may be of any of various different longitudinal lengths may be provided for use in a given propping system in sets or groups of a plurality of such embodiment prop sections, with at least one or more of the prop sections of a given set or group being of a first longitudinal length and at least one or more other ones of the prop sections of the given set or group being of a second longitudinal length, which first and second longitudinal lengths are different from each other. Such a given set or group of prop sections may even include at least one or more yet further prop sections of a third, or possibly even of third and fourth, or perhaps even yet further possibly of third, fourth and fifth (or even more) longitudinal lengths, which third, fourth, fifth etc longitudinal lengths are each different still from each other and from the first and the second longitudinal lengths.

Each such set or group of embodiment prop sections may also differ from other sets/groups of prop sections in the overall load-bearing and strength/weight ratios of the prop sections within each set/group, for example by virtue of dimensional and/or configurational variations (especially minor variations) in various of the prop sections' constructional components, elements or portions, as well as variations in the thickness and/or grade of the plate/sheet material used to form the various constructional components, elements or portions. In this manner different sets/groups of prop sections may be designed for use in for example "light duty", "medium duty" or "heavy duty" propping applications, depending for instance on industry requirements or specifications or the specific practical demands of a particular propping system.

Accordingly, in another aspect of the present invention there is provided, as a kit or set of component parts, especially one which forms a propping system or part of a propping system, a plurality of prop sections, each being a prop section according to the first aspect of the invention or any embodiment thereof. In some embodiment forms of this aspect, the kit or set of component parts may optionally further include attachment means for attaching plural ones of the prop sections together in an end-to-end manner via their respective transverse end members. Such attachment means may comprise any suitable fixing or connection means, e.g. one or more (especially a plurality of) bolts, screws, nuts, pins, clips, detents or other retaining or fixing devices, or alternatively may comprise a jack assembly for joining a pair of the prop sections together end-to-end but in a combined-longitudinalle ngth-a djusta b le manner.

Furthermore, in yet another aspect of the present invention there is provided, as an alternative kit or set of component parts, especially one which forms a propping system or part of a propping system, at least one prop section according to the first aspect of the invention or any embodiment thereof, together with one or more additional components of the propping system, such as a jack or jack base assembly, a prop foot plate or ground support, or a beam, strut, brace or other supporting member of the propping system.

In some embodiments of the preceding defined kit or set of parts which further includes a jack or jack base assembly, the kit or set of parts may further include means for attaching a load-bearing/exerting portion or member of the jack base assembly to a respective transverse end member of the at least one prop section. Likewise such attachment means may comprise any suitable fixing or connection means, e.g. one or more bolts, screws, nuts, pins, clips, detents or other retaining or fixing devices.

Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. Thus, any one or more features referred to or described with reference to one particular embodiment should be construed as being applicable to any or all embodiments, unless expressly stated otherwise or such features are incompatible.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the present invention in its various aspects will now be described in detail, by way of non-limiting example only, with reference to the accompanying drawings, in which: FIGURES 1(a), 1(b), 1(c), 1(d), 1(e) and 1(f) are various views illustrating various type of propping systems in deployment which incorporate various prop sections according to various embodiments of the invention; FIGURE 2 shows in general illustrative terms some examples of the kinds of components of an overall propping system such as those being deployed as shown in FIGS. 1(a)-(f), which components include a selection of prop sections according to embodiments of the invention; FIGURE 3 is a perspective view of a first group of prop sections of different lengths and each being an embodiment of the invention, these embodiment prop sections being of an embodiment group designated as being of a light-duty rating for practical purposes; FIGURE 4 is an illustrative transverse cross-sectional view of any of the individual prop sections shown in FIG. 3; FIGURES 5(a), (b), (c), (d) and (e) are perspective views of individual ones of the embodiment prop sections shown in FIGS. 3 and 4; FIGURE 6 is a perspective view of a second group of prop sections of different lengths and each being an embodiment of the invention, these embodiment prop sections being of an embodiment group designated as being of a medium-duty rating for practical purposes; FIGURE 7 is an illustrative transverse cross-sectional view of any of the individual prop sections shown in FIG. 6; FIGURES 8(a), (b), (c), (d), (e) and (f) are perspective views of individual ones of the embodiment prop sections shown in FIGS. 6 and 7; FIGURE 9 is a perspective view of a third group of prop sections of different lengths and each being an embodiment of the invention, these embodiment prop sections being of an embodiment group designated as being of a heavy-duty rating for practical purposes; FIGURE 10 is an illustrative transverse cross-sectional view of any of the individual prop sections shown in FIG. 9; FIGURES 11(a), (b), (c) and (d) are perspective views of individual ones of the embodiment prop sections shown in FIGS. 9 and 10.

DETAILED DESCRIPTION OF EMBODIMENTS

Referring firstly to FIGS. 1(a) -1(f), these FIGS. illustrate some representative schematic examples of various types of propping system to which various embodiments of the present invention may be applied, and in particular which include the deployment and use of various embodiments of prop section according to the invention.

FIGS. 1(a), 1(b) and 1(c) show, respectively, perspective, end-on and close-up-partial views of an example of a propping and needling system, in which a series of uniformly spaced-apart vertical prop sections P1 according to one embodiment of the invention are used to support a building structure B via respective ones of a series of horizontal needles (i.e. short I-beams) N extending beneath the building structure. Each vertical prop section P1 is braced so as to help maintain its vertical supporting orientation by respective ones of a series of obliquely inclined prop sections P2 according to another (or the same) embodiment of the invention. Additional diagonally and/or horizontally mounted support/bracing poles S are also employed to provide further stabilising support to the overall propping/needling system structure. Each of the prop sections P1 and P2 is supported on the ground via a respective foot plate Fl, E2 which is carried on the end of a length-adjustable rod or jack assembly J1, J2 which is attached to the respective prop section P1, P2 via the latter's lower end plate EL1, EL2. The prop sections P1, P2 of each pair are interconnected via a rod connector (which may itself be length-adjustable, if desired or appropriate) which is anchored to the respective inclined prop section P2 of each pair via the latter's opposite (upper) end plate EU2.

FIG. 1(d) is a perspective view of an example of a façade retention system, in which a pair of propping towers T formed from interconnected plural prop sections P each according to one or more embodiments of the invention are used to support and retain in an upright condition the façade of a building B, e.g. during its repair, reconstruction or demolition.

FIGS. 1(e) and 1(f) show, respectively, perspective and close-up-partial-underside views of a bridge propping and jacking system, in which a pair of propping towers T formed from interconnected plural prop sections P each according to one or more embodiments of the invention are used to support and jack up a bridge BR. Each of the main vertical prop sections P is made up of a series of individual prop sections interconnected end-to-end directly to one another, and is supported on the ground via a respective foot plate F which is carried on the end of a length-adjustable rod or jack assembly J which is attached to the respective lowermost vertical prop section P via the latter's lower end plate EL. As shown in FIG. 1(f), the upper end of each propping tower T supports the bridge structure BR via support beams M and additional (e.g. hydraulic) jacks J H. It is to be understood that the propping systems illustrated in FIGS. 1(a) -1(f) are just a selection of some illustrative representative examples of overall propping systems which may incorporate prop sections in accordance with embodiments of the present invention, and many other different propping arrangements may be designed for use in any particular building, civil engineering or industrial scenario for which propping is needed.

FIG. 2 shows in general illustrative terms some examples of the kinds of components of an overall propping system which may be used in the deployment thereof, including those example systems illustrated in FIGS. 1(a) -1(f). These components include, for instance, one or more jacks or jack assemblies J1, J2 (which may be of different types), foot plate supports F, support legs S, tension braces T, and -crucially -a selection of props or prop sections P, each such prop/prop section P being according to an embodiment of the present invention.

Turning to FIGS. 3 to 5, 6 to 8, and 9 to 11, each of these groups of FIGS. shows various prop sections according to embodiments of the invention, but presented in the form of three distinct kits or sets or groups of prop sections which are designated "light duty", "medium duty" and "heavy duty", respectively. These three kits/sets/groups of prop sections are shown collectively in FIGS. 3,6 and 9, respectively, and the prop sections within each group each have a different longitudinal length, so that they may be used in a modular fashion and/or so as to provide optimum flexibility in being interconnectable in various combinations and physical arrangements to provide any of a range of different designs and configurations of propping system that meets the requirements that any given propping application may demand.

The "duty"-rating of the various kits/sets/groups of prop sections is determined principally by the overall range of thicknesses of the various plate/sheet/web materials from which the various component parts of each prop section within each respective group is formed, but also by the overall dimensions of each prop section (which may also affect its overall strength/weight ratio) and/or the presence (or not) of various bracing members and/or stiffener elements that some of the prop sections within each group may incorporate in its structure. The particular physical properties of stiffness and strength/weight ratio etc that a particular duty-rating may demand may for instance be set by industry standards, health & safety legal requirements, or the specific practical requirements of a given propping system for a specific building, civil engineering or industry application, or a combination of any of the aforesaid However, the fundamental constructional principles and features of each of the prop sections within each of the kits/sets/groups is the same, although some of the prop sections (e.g. the shorter ones) may not contain some of the additional optional structural features such as the bracing member(s) and/or stiffener element(s). Furthermore, in those prop sections which do contain one or more of those additional optional structural features being the bracing member(s) and/or stiffener element(s), then different lengths of prop section may contain different numbers of such bracing members and/or stiffener elements, for example depending on a given prop section's longitudinal length, duty rating and overall strength/weight ratio and stiffness properties that it is required to have.

Looking in particular at the light-duty kit/set/group of prop sections 100 of FIG. 3, these comprise prop sections 100 of longitudinal lengths L of 2 m, 1 m, 0.5 m, 0.25 m and 0.14 m. Looking at the medium-duty kit/set/group of prop sections 200 of FIG. 6, these comprise prop sections 200 of longitudinal lengths L of 2 m, 1 m, 0.5 m, 0.25 m, 0.14 m and 0.08 m. And looking at the heavy-duty kit/set/group of prop sections 300 of FIG. 9, these comprise prop sections 300 of longitudinal lengths L of 2 m, 1 m, 0.5 m and 0.25 m. Of course, the longitudinal lengths of any individual one(s) of the prop sections 100, 200, 300 in each of the above kits/sets/groups may be different from those precise lengths as quoted, depending on specific practical requirements.

Looking firstly at the light-duty kit/set/group of prop sections 100 of FIG. 3, these are all based on a common fundamental cross-sectional shape and configuration as shown in FIG. 4, based on a pair of back-to-back united channel sections 110, 120. FIG. 5(a) illustrates the 0.14 m version, FIG. 5(b) illustrates the 0.25 m version, FIG. 5(c) illustrates the 0.5 m version, FIG. 5(d) illustrates the 1 m version, and FIG. 5(e) illustrates the 2 m version.

The channel sections 110, 120, which are formed from -2 mm sheet steel (such as any of those steels commercially available under the designations S700MC, e.g. of the "Strenx" (trade mark) series from SSAB AB or of the "Ympress" (trade mark) series from Tata Steel), are each closed on their interior sides and open on their exterior sides. The channel sections 110, 120 are united at each of their longitudinal ends by a respective end plate 130A, 130B. They are attached by welding, e.g. fillet welding. Each of the end plates 130A, 130B is provided with an appropriate series of holes or apertures 130H to enable it to act as a site or means for enabling the prop section 100 to be interconnected end-to-end to another prop section via a relevant one of its own end plates/members, and/or to be mounted on or connected to one or more other components of the propping system, especially a jack or jack base assembly, or a prop foot plate or ground support, or one or more beams, struts or other support members of the propping system. Each end plate 130A, 130B is further provided with an appropriately dimensioned central through-hole or aperture 180 for accommodating and allowing passage therethrough of a threaded rod or bar (not shown) of a jack or jacking assembly that may be used in conjunction with the prop section 100 as part of the overall propping system.

Each of the channel sections 110, 120 comprises a generally planar rear major portion 110R, 120R, and a pair of minor flange portions 110F, 120E extending forwardly (i.e. externally) away from opposite ends of the respective rear major portion 110R, 120R. Each of the minor flange portions 110F, 120F in each pair extend outwardly from opposite sides of the respective rear major portion 110R, 120R at substantially a right angle (i.e. 90 degrees) relative to the general plane of the respective rear major portion 110R, 120R. In each channel section 110, 120 the height/width of the respective rear major portion 110R, 120R (i.e. the transverse height/width of the respective rear major portion 1105, 1205 in the plane of the material thereof) is approximately 4 times the corresponding width (i.e. the transverse width in the plane of the material thereof) of each of the respective minor flange portions 110F, 120F extending outwardly therefrom. In this manner, the general overall form of each of the channel sections 110, 120 in cross-section is thus approximately rectangular, rather than square, as shown in FIG. 4.

In each of the channel sections 110, 120, the respective rear major portion 110R, 120R comprises a substantially planar central portion 110C, 120C, and extending to either side thereof is a pair of lateral side portions 110L, 120L also substantially planar but each being stepped rearwardly relative to the central portion 110C, 120C and joined thereto by a respective one of a pair of ramp, shoulder or bridging portions 110B, 120B. The transverse height/width (i.e. in the plane of the material thereof) of each planar central portion 110C, is approximately 3 to 4 times the corresponding transverse height/width (i.e. in the plane of the material thereof) of each of the lateral side portions 110L, 120L, and the pair of lateral side portions 110L, 120L are themselves of substantially the same transverse height/width. The respective rear major portions 1105, 120R, or at least the substantially planar central portions 110C, 120C thereof, of the pair of channel sections 110, 120 are configured and arranged such that they are spaced apart by a gap of a suitable distance for accommodating therevvithin the above-mentioned threaded rod or bar (not shown) of a jack or jacking assembly that may be used in conjunction with the prop section 100 as part of the overall propping system.

In each of the channel sections 110, 120, each of the minor flange portions 110F, 120F in each pair thereof comprises a planar primary flange portion 110FP, 120FP oriented perpendicularly with respect to the planar central portion 1100, 1200 of the respective rear major portion 110R, 1205 of the respective channel section 110, 120. Furthermore, each of the minor flange portions 110F, 120F in each pair thereof comprises a terminal secondary flange portion 110FT, 120FT extending from the respective primary flange portion 110FP, 120FP and terminating the said respective minor flange portion 110F, 120F. Each terminal secondary flange portion 110FT, 120FT extends perpendicularly with respect to its respective primary flange portion 110FP, 120FP, such that in each channel section 110, 120 the terminal secondary flange portions 110FT, 120FT of each pair extend and point towards one another in opposite directions, and in a common plane in space. In each channel section 110, 120, each terminal secondary flange portion 110FT, 120FT of each pair is of a relatively short transverse height/width, i.e. no greater than the corresponding transverse height/width (in parallel planes in space) of the corresponding respective lateral side portion 110L, 120L of the respective rear major portion 110R, 120R of the respective channel section 110, 120.

As shown in the context of the specific length prop sections of FIGS. 5(b), 5(c), 5(d) and 5(e), which demand it for practical strength and stiffness considerations, some of the prop sections 100 further comprise, mounted (e.g. by fillet welding) internally of and between the pair of channel sections 110, 120, one or more bracing members 140. Each bracing member 140 is attached between the respective rear major portions 110R, 120R of the channel sections 110, 120 between the interior-facing rear walls thereof, especially between the interior-facing rear walls of the respective planar central portions 1100, 1200 of the rear major portions 110R, 120R of the respective channel sections 110, 120. Each bracing member 140 is thus dimensioned such that it spans and substantially fills or matches the size of the gap between the respective rear major portions 110R, 120R of the respective channel sections 110, 120. Each bracing member 140 comprises an elongated generally C-shaped channel section, with its own minor flange portions providing the necessary sites of mounting/attachment to the main channel sections 110, 120. The longitudinal length of each C-shaped channel section forming each bracing member 140 substantially matches the transverse height/width (i.e. in the plane of the material thereof) of the rear major portions 110R, 120R of the respective main channel sections 110, 120. However, other profiles or configurations of bracing members may be employed if desired or more appropriate from strength-or stiffness-imparting considerations.

An appropriate number of such bracing members 140 may be provided in any given prop section 100, depending for example on the longitudinal length L thereof and the degree of stiffness and strength it is desired to have. For instance, the prop sections 100 of FIGS. 5(a), 5(b) and 5(c) do not comprise any such bracing members, since their longitudinal lengths L (0.14 m, 0.25 m & 0.5 m) make this unnecessary. However, the prop section 100 of FIG. 5(d) comprises one such bracing member 140, positioned halfway along the prop section midway between its respective end plates 130A, 130B, and the prop section 100 of FIG. 5(e) comprises three such bracing members 140, located in a regular, uniform spaced apart fashion at equidistant intervals (e.g. typically at 0.5 metre intervals) along the longitudinal length L of that prop section 100.

Likewise, as also shown in the context of the specific length prop sections of FIGS. 5(d) and 5(e), which demand it for practical strength and stiffness considerations, some of the prop sections 100 further comprise, externally mounted on each of the channel sections 110, 120, one or more stiffener elements 150. Each stiffener element 150 is in the form of a fillet insert or plate or flange, especially one which is generally flat and rectangular in shape, and each one is oriented transversely and perpendicularly to the longitudinal length L of the prop section 100. Each stiffener element 150 is attached, again by e.g. fillet welding, to at least the externally-facing wall of each respective central planar portion 110C, 120C of the respective rear major portion 110R, 1205 of the respective channel section 110, 120, and additionally also to the respective planar primary flange portions 110FP, 120FP of the respective minor flange portions 110F, 120F thereof.

As with the provision in various embodiment prop sections of bracing members 140 as discussed above, an appropriate number of stiffener elements 150 may be provided in any given prop section 100, depending for example on the longitudinal length [thereof and the degree of stiffness and strength it is desired to have. For instance, the prop sections 100 of FIGS. 5(a), 5(b) and 5(c) do not comprise any such stiffener elements on either of the channel sections 110, 120, since their longitudinal lengths [(0.14 m, 0.25 m & 0.5 m) make this unnecessary. However, the prop section 100 of FIG. 5(d) comprises two such stiffener elements on each channel section 110, 120, spaced apart from each other at 0.5 metre longitudinal spacings, and the prop section 100 of FIG. 5(e) comprises four such stiffener elements 150, again located in a regular, uniform spaced apart fashion at equidistant intervals (e.g. again typically at 0.5 metre spacings) along the longitudinal length L of that prop section 100.

It will be noted that in those embodiment prop sections 100 (such as those of FIGS. 5(d) & 5(e)) where both one or more bracing members 140 and one or more stiffener elements are provided, then it is preferable (as illustrated in these example embodiment prop sections) that the longitudinal position of the or each stiffener element 150 on the exterior sides of the channel sections 110, 120 is such that it/they each lie intermediate (especially midway between) the longitudinal positions of respective ones of the bracing member(s) 140 located to the interior sides of the channel sections 110, 120 (especially where plural such bracing members 140 are provided) or intermediate (especially midway between) the longitudinal positions of a bracing member 140 and either one of or each of the end plates 130A, 130B members (especially where only one bracing member 140 is provided) -and vice versa. Thus, in such embodiment prop sections 100 where both one or more external stiffener elements 150 and one or more internal bracing members 140 are provided on opposite faces/walls of a given channel section 110, 120, then the relevant stiffener element(s) 150 and bracing member(s) 140 are preferably out-of-register with respect to each other on either side of the relevant channel section 110, 120, so that on both sides of the relevant channel section 110, 120 no two stiffener elements 150 and bracing members 140 are at the same or approximately the same longitudinal position along the length L of the relevant channel section 110, 120 and they are longitudinally spaced apart relative to each other on those opposite sides of the relevant channel section 110, 120.

As also shown in some of the embodiment prop sections 100 of FIGS. 3, 4 and 5, i.e. in those of FIGS. 5(b), (c), (d) and (e), if desired or appropriate (depending for example on the longitudinal length L of the prop section 100 and the degree of stiffness and strength it is desired to have) each of the channel sections 110, 120 is provided with (e.g. by a post-forming drilling or cutting procedure) one or more, especially a plurality of, holes or apertures 160 extending through the material thereof, in order to further enhance the strength and stiffness of the relevant plate/sheet/web material. These holes/apertures 160 are provided in either or both of the rear major portions 110R, 120R of the respective channel sections 110, 120 and/or (depending on the embodiment) in each of the minor flange portions 110F, 120F. Where plural such holes/apertures 160 are provided, they are arranged in one or more regular and symmetrically positioned series or rows, as illustrated by way of example in the various FIGS. 3 to 5 of this group.

Turning to the medium-duty prop sections 200 of FIGS. 6 to 8 and the heavy-duty prop sections 300 of FIGS. 9 to 11, in each case their various structural components, elements, parts or features which correspond to those respective ones thereof of the light-duty embodiment prop sections 100 of FIGS. 3 to 5 are designated with the same reference numerals but in each case incrementally increased by 100 moving from one group of prop sections to the next.

Thus, looking next at the medium-duty kit/set/group of prop sections 200 of FIG. 6, these are all based on a common fundamental cross-sectional shape and configuration as shown in FIG. 7, based on a similar pair of back-to-back channel sections 210, 220. FIG. 8(a) illustrates the 0.08 m version, FIG. 8(b) illustrates the 0.14 m version, FIG. 8(c) illustrates the 0.25 m version, FIG. 8(d) illustrates the 0.5 m version, FIG. 8(e) illustrates the 1 m version, and FIG. 8(f) illustrates the 2 m version.

Some (though not all) of the prop sections 200 of FIGS. 8(a) -8(f) variously comprise one or more internal bracing members 240 and/or external stiffener elements 250, as illustrated by way of example in these FIGS. The presence of, numbers of, the various longitudinal positionings of, and the relative spacings of (both absolute and relative), of the various internal bracing members 240 and external stiffener elements 250 in each prop section 200 follow the same principles, criteria and variations as between different prop sections 200 of the different longitudinal lengths as apply to the corresponding internal bracing members 140 and external stiffener elements 150 of the embodiment prop sections 100 of FIGS. 3 to Sand discussed above, so will not be described in further detail again here.

And going further, looking next at the heavy-duty kit/set/group of prop sections 300 of FIG. 9, these are all based on a common fundamental cross-sectional shape and configuration as shown in FIG. 10, based on a similar pair of back-to-back channel sections 110, 120.

FIG. 11(a) illustrates the 0.25 m version, FIG. 11(b) illustrates the 0.5 m version, FIG. 11(c) illustrates the 1 m version, and FIG. 11(d) illustrates the 2 m version.

Again, various ones of the prop sections 300 of FIGS. 11(a) -11(d) variously comprise one or more internal bracing members 340 and/or external stiffener elements 350, as illustrated by way of example in these FIGS. Again, the presence of, numbers of, the various longitudinal positionings of, and the relative spacings of (both absolute and relative), of the various internal bracing members 340 and external stiffener elements 350 in each prop section 300 also follow the same principles, criteria and variations as between different prop sections 300 of the different longitudinal lengths as apply to the corresponding internal bracing members 140 and external stiffener elements 150 of the embodiment prop sections of FIGS. 3 to 5 and discussed above, so again wHI not be described in further detail again here.

It is to be understood that the above description of some specific embodiments of the invention in terms of their various features and aspects has been by way of non-limiting example(s) only, and various modifications may be made from what has been specifically described and illustrated whilst remaining within the scope of the invention as set out in the appended claims.

Throughout the description and claims of this specification, the words "comprise" and "contain" and linguistic variations of those words, for example "comprising" and "comprises", mean "including but not limited to", and are not intended to (and do not) exclude other moieties, additives, components, elements, integers or steps.

Throughout the description and claims of this specification, the singular encompasses the plural unless expressly stated otherwise or the context dictates otherwise. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless expressly stated otherwise or the context dictates requires otherwise.

Furthermore, through this specification any feature, component, element, integer, characteristic, property, compound, chemical moiety or group described in conjunction with a particular aspect, embodiment or example of the invention is/are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith or expressly stated otherwise.

Claims (26)

1. CLAIMS1. A prop section for use in a propping system, comprising: a pair of elongate channel sections, each channel section comprising a generally at least partially substantially planar rear major portion and a pair of minor flange portions extending outwardly from opposite sides of the rear major portion, wherein the elongate channel sections are oriented back-to-back relative to each other with the rear major portion of one of the channel sections facing the rear major portion of the other of the channel sections and the respective pairs of minor flange portions extending outwardly from their respective rear portions in generally opposite outward directions; and a pair of transverse end members bounding respective longitudinal ends of the pair of back-to-back elongate channel sections and being attached thereto so as to unite the pair of channel sections together to form the prop section.
2. 2. A prop section according to claim 1, wherein, in each of the channel sections, the height or width of the respective rear major portion (i.e. the transverse height/width of the rear major portion in the plane of the material thereof) is greater than the corresponding width (i.e. the transverse width in the plane of the material thereof) of each of the respective minor flange portions extending outwardly therefrom.
3. 3. A prop section according to claim 1 or claim 2, wherein, in each of the channel sections, the respective rear major portion comprises a substantially planar central portion, and extending to either side of the central portion a pair of lateral side portions also substantially planar but each being stepped rearwardly relative to the central portion and joined thereto by a respective one of a pair of ramp or shoulder or bridging portions; optionally wherein the respective rear major portions, or at least the substantially planar central portions thereof, of the pair of channel sections are configured and/or arranged such that they are spaced apart by a gap of a suitable distance for accommodating therewithin a threaded rod or bar of a jack or jacking assembly that is used in conjunction with the prop section as part of the overall propping system.
4. 4. A prop section according to claim 3, wherein the transverse height/width (i.e. in the plane of the material thereof) of the respective planar central portion is from about 3 or 4 or 5 times up to about 7 or 8 or 9 or 10 or 12 or 15 times the corresponding transverse height/width (i.e. in the plane of the material thereof) of each of the lateral side portions.
5. 5. A prop section according to any preceding claim, wherein, in each of the channel sections, each of the minor flange portions in each respective pair thereof extending outwardly from opposite sides of the rear major portion so extends outwardly therefrom at an angle of substantially about 90 degrees relative to the general plane of the respective rear major portion.
6. 6. A prop section according to any preceding claim, wherein, in each of the channel sections, each respective one of the minor flange portions in each pair thereof extending outwardly from opposite sides of the respective rear major portion comprises at least a substantially planar primary flange portion, optionally which primary flange portion is oriented substantially perpendicularly with respect to the planar central portion of the respective rear major portion of the respective channel section.
7. 7. A prop section according to claim 6, wherein, in each of the channel sections, each respective one of the minor flange portions in each pair thereof comprises a respective terminal secondary flange portion extending from the respective primary flange portion and terminating the said respective minor flange portion.
8. 8. A prop section according to claim 7, wherein each respective terminal secondary flange portion extends substantially perpendicularly with respect to the respective primary flange portion of the respective minor flange portion, such that the pair of terminal secondary flange portions of the pair of minor flange portions of each channel section extend and point towards one another in substantially opposite directions, optionally in substantially a common plane in space.
9. 9. A prop section according to claim 8, wherein each respective terminal secondary flange portion of the respective minor flange portion is of a relatively short transverse height/vvidth which is no greater than the corresponding transverse height/width (in substantially parallel planes in space) of the corresponding respective lateral side portion of the respective rear major portion of the respective channel section.
10. 10. A prop section according to any preceding claim, wherein each of the pair of transverse end members bounding and being attached to the respective longitudinal ends of the pair of back-to-back elongate channel sections comprises, or is in the form of, a plate or sheet or other substantially flat or planar member.
11. 11. A prop section according to claim 10, wherein each end member is provided with an arrangement of holes, apertures or slots, for enabling the prop section to be interconnected, optionally in an end-to-end manner, to another prop section via a relevant one of its own end members, and/or for enabling the prop section to be mounted or connected to one or more other components of the propping system.
12. 12. A prop section according to any preceding claim, further comprising, mounted or attached internally of and between the pair of channel sections, one or more bracing members.
13. 13. A prop section according to claim 12, wherein the or each bracing member is mounted or attached between the respective rear major portions of the respective channel sections between the interior-facing walls thereof, and the or each bracing member is dimensioned such that it spans and substantially fills or matches the size of the gap between the respective rear major portions of the respective channel sections.
14. 14. A prop section according to claim 12 or claim 13, wherein the or each bracing member comprises an elongate generally C-shaped channel section, whose minor flange portions are the portions which provide the necessary sites of mounting/attachment to the main channel sections of the prop section.
15. 15. A prop section according to any one of claims 12 to 14, wherein the longitudinal length of the or each bracing member substantially matches or is approximately equal to the transverse height/width (i.e. in the plane of the material thereof) of the rear major portions of the respective main channel sections of the prop section.
16. 16. A prop section according to any one of claims 12 to 15, wherein either: (i) one said bracing member is provided, and it is located substantially midway (i.e. approx. halfway) along the longitudinal length of the prop section; or (ii) a plurality of said bracing members are provided, and they are located in a regular, uniform spaced apart fashion at equidistant intervals along the longitudinal length of the prop section.
17. 17. A prop section according to any preceding claim, wherein each of the channel sections has externally mounted thereon or attached thereto one or more stiffener elements.
18. 18. A prop section according to claim 17, wherein the stiffener element(s) is/are mounted on or attached to the respective externally-facing wall of the respective channel section, optionally to at least the externally-facing wall of the central planar portion of the rear major portion thereof, and further optionally also to the respective planar primary flange portions of the respective minor flange portions thereof.
19. 19. A prop section according to claim 17 or claim 18, wherein either: (i) one said stiffening element is provided on each channel section, and it is located substantially midway (i.e. approx. halfway) along the longitudinal length of the prop section; or (ii) a plurality of said stiffening elements are provided on each channel section, and they are located in a regular, uniform spaced apart fashion at equidistant intervals along the longitudinal length of the prop section.
20. 20. A prop section according to any one of claims 17 to 19, as dependent through any one of claims 12 to 16, wherein the longitudinal position of the or each of the stiffener elements on the exterior sides of the channel sections is such as to lie intermediate the longitudinal positions of (optionally midway between) respective ones of the bracing members located to the interior sides of the channel sections (in the case where plural such bracing members are provided) or intermediate the longitudinal positions of (optionally midway between) a bracing member and either one of or each of the end members (in the case where only one bracing member is provided).
21. 21. A prop section according to claim 20, wherein both one or more external stiffener elements and one or more internal bracing members are provided on opposite faces/walls of a given channel section, and the relevant stiffener element(s) and bracing member(s) are out-of-register with respect to each other on either side of the relevant channel section, so that on both sides of the relevant channel section no two stiffener elements and bracing members are at the same or approximately the same longitudinal position along the length of the relevant channel section and they are longitudinally spaced apart relative to each other on those opposite sides of the relevant channel section.
22. 22. A prop section according to any one of claims 17 to 21, wherein the or each stiffener element comprises a flat, rectangular fillet insert, web, plate or flange, and is mounted or attached to each channel section such that its general plane is oriented transversely and perpendicularly to the longitudinal length of the prop section.
23. 23. A prop section according to any preceding claim, wherein each of the channel sections is provided or formed with one or more, optionally a plurality of, holes or apertures or slots/slits therein and extending through the material thereof, in order to further enhance the strength and stiffness of the channel section, optionally wherein the holes/apertures are provided in either or both of the rear major portions of the respective channel sections and/or in each of the minor flange portions extending from the respective rear major portion thereof.
24. 24. A kit or set of component parts forming a propping system or part of a propping system, comprising a plurality of prop sections, each being a prop section according to any one of claims 1 to 23.
25. 25. A kit or set of component parts according to claim 24, further including attachment means for attaching plural ones of the prop sections together in an end-to-end manner via their respective transverse end members, wherein the attachment means comprises one or more fixing or connection or retaining means, or a jack assembly for joining a pair of the prop sections together end-to-end but in a combined-longitudinal-length-adjustable manner.
26. 26. A kit or set of component parts forming a propping system or part of a propping system, comprising at least one prop sections according to any one of claims 1 to 23, together with one or more additional components of the propping system selected from a jack or jack base assembly, a prop foot plate or ground support, or a beam, strut, brace or other supporting member of the propping system.