P100/011 28/5/91 Regulation 3.2 AUSTRALIA Patents Act 1990 ORIGINAL COMPLETE SPECIFICATION STANDARD PATENT Name of Applicant: Engineered by Holland Pty Ltd Actual Inventor Martin Charles Holland Address for service is: WRAYS Ground Floor, 56 Ord Street West Perth WA 6005 Attorney code: WR Invention Title: Reinforced Sheet and Structural Members Formed from Same The following statement is a full description of this invention, including the best method of performing it known to me: -1- Reinforced Sheet and Structural Members formed from same Field of the Invention The present invention generally relates to an improvement in reinforcement of structural members, In particular, the invention relates to the strengthening of a 5 sheet of material. Background Art It is common practice in various industries to corrugate, dimple or indent sheets of metal in one or more directions in order to increase the sheet's structural strength. One type of sheet and a method for making same is disclosed US Patent 10 2,441,476 to Ewald. This patent addressed the problems with the prior art (at that time) whereby the process of dimpling, or otherwise altering the sheet metal did not improve the strength of the sheet metal in all directions. The patent described a continuous reinforced metal sheet with a plurality of flat topped alternately elevated and depressed frustums. 15 Another type of sheet and a method for making sections from the sheet is disclosed in US Patent 4,490,958 to Lowe. This patent addresses the common problems associated with the prior art whereby the process of dimpling, or otherwise altering the sheet metal did not improve the strength of the sheet metal in all directions. Lowe describes a variety of sections roll formed into a chosen 20 profile. The sections consisted of corrugated flanges and metal struts positioned vertically within the section to strengthen that section. A series of rib like projections extending from the upper flange and extending in a trapezoid pattern are spot welded to strengthen the upper flange and middle web. However, with this arrangement problems will arise in the upper flange caused by a bending 25 moment at this particular point, weakening the section as load is concentrated on this small point and as it is unable to be transferred across a larger surface area, the load may cause failure of the section at this point The process of dimpling, or otherwise altering the sheet metal is suitable for continuous sheets. However, problems arise in situations where a non-planar 30 shape is required, such as a lintel, as any bending or folding of a dimpled or corrugated plate typically resulted in the deformation of the dimples/corrugations -2during the bending process. Such deformation potentially reduces the strength of the sheet metal and results in buckling of the section. The preceding discussion of the background to the invention is intended only to facilitate an understanding of the present invention. It should be appreciated that 5 the discussion is not an acknowledgement or admission that any of the material referred to was part of the common general knowledge as at the priority date of the application. It is an objective of this invention to provide an improved reinforced sheet having increased strength and design flexibility and which retains these characteristics 10 during bending and folding operations. SUMMARY OF INVENTION As mentioned, the process of strengthening sheet material, such as by indenting, or otherwise altering the sheet metal is suitable for continuous sheets. However, to further prevent potential weakness at the point of the joins either heavier gauge 15 metal must be used or, as proposed here the addition of an angled tie to help distribute load to a larger surface area. In this way lighter gauge metal can be used which will result in a cost decrease, a lightweight product and less emission of CO2. In the specification the term strengthening. includes internal bracing of a hollow 20 section as well as forming indentations in the sheet metal. In the specification the term 'indentation' is to be interpreted as including dimples, troughs, corrugations or other depressions formed in the material, and also includes those indentations created by forming a peak, as well as those structures which deviate from the planar surface of the structural member.. 25 In the specification the term corrugated/ corrugations is to be interpreted as a sheet with an arrangement of vertical gutters and ridges formed. For example these may be in a square shaped profile. The corrugations may be vertical corrugations, In the specification the term 'tie' is to be interpreted as including the angled fold of 30 a hollow section to form a sloped edge for fixing a second sheet of metal, as will be explained below. -3- An advantage of this invention is found in providing a reinforced sheet suitable for forming a wide range of structural members which may in turn be used in other applications. The present invention provides a reinforced sheet of material from which a 5 structural member may be formed by folding the sheet at one or more fold lines, the sheet incorporates a strengthening means, such as a plurality of indentations, whereby the indentations are formed relative to the one or more fold lines such that the indentations at least do not compromise the strength of the formed structural member. 10 The present invention provides a reinforced sheet of material from which a structural member may be formed by folding the sheet at one or more fold lines, the sheet incorporates a strengthening means, such as a one or more of a combination of a plurality of indentations, corrugations and/or braces, whereby the indentations are formed relative to the one or more fold lines such that the 15 indentations at least do not compromise the strength of the formed structural member. Preferably the indentations result in a stronger structural member than what would be formed from a sheet of material without indentations. The material may be metal, plastic, fibrous material, wood or other material which 20 may retain or have an indentation formed therein. For the purposes of simplicity the specification will refer to a sheet of material being sheet metal/metal sheet. However, it is to be understood that this can be interchanged with the aforementioned materials and still fall within the scope of this invention. At least some of the indentations are in close proximity to the fold line. The 25 indentations may be located either side of the fold line. The indentations may have a portion of their periphery in engagement with the fold line. The indentations may be uniformly spaced with respect to the fold line. The indentations may be spaced in a staggered manner with respect to the fold line. 30 The present invention further provides a structural member at least part constructed from a metal sheet as hereinbefore described. -4- The structural member may comprise a first structural elongate element formed from a first metal sheet and a second metal sheet, both folded to the required shape, whereby the first and second sheets may be fitted together to form the structural member, wherein at least the first metal sheet incorporates a 5 strengthening means such as indentations or bracing. The structural elongate element is preferably hollow, whereby the indentations extend into the hollow section. The structural elongate element is preferably hollow, whereby the bracing extends across the hollow section. The first and second sheets may be welded together. Preferably the welding 10 occurs across the apex of the indentations to create a join with enhanced performance, or at the point the bracing engages the inner surface if the walls of the hollow section. The structural member may comprise a plurality of structural elongate elements to allow the formation of the required structural section. For example, to create an I 15 beam the structural member will comprise a first elongate element to provide the web and two second structural elongate elements to provide the flanges. In one aspect of the invention the structural member may also comprise a corrugated elongate element. The corrugated elongate element may be in the form of a single leaf corrugated sheet to form the web or angle of the required 20 structural member. However, the corrugated elongate element may also comprise the joining of two sheets (one being corrugated and one being flat) to form a hollow corrugated elongate element. In one aspect of the invention the structural member may be in the form of a single leaf sheet configured to form a hollow section whereby during construction 25 an end of the sheet is bent to provide a brace extending between inner walls of the hollow section. One or more of the structural elongate elements may have at least one angled edge. The angled edge may provide an angle tie. The angled edge of the structural member extends to form the angled tie and is designed to fix to a further 30 elongate element or a corrugated elongate element. -5- One or more of the structural elongate elements may have at least one v-shaped formation along its length. The v-shaped formation may provide an angle tie along the elongate element. The v-shaped formation of the structural member extends to form the angled tie and is designed to fix to a further elongate element 5 or a corrugated elongate element. One or more of the structural elongate elements may have both at least one v shaped formation along its length and at least one angled edge. In those cases were a corrugated elongate element is to be secured the width of the angled edge/v shaped formation mirrors the pitch of the corrugated web to 10 enable a precise fit of the two sheets of metal. The angled tie prevents bending moments from developing in the corners of the structural member (e.g. flanges) and restrains stresses so as to remain under a state of compression and tension, (depending on the direction of the load). The angle of the tie may be 450 and may be any width; however, 0.2-2 15 centimetres is sufficient to create a solid connection emanating from the fold of the elongate element and fixing to an adjoining mitred corners on a further elongate element. However, this width may vary and remain within the construct of the invention. An intention of the invention is to construct a hollow section comprising a 20 combination of braced, indented, corrugated and/or flat sheets with an angled tie formed from at least one of the sheets to create a section of increased strength and performance. This manner of construction allows a structural member to be formed having the same or greater strength capabilities than the same structural member made from 25 a solid construction. Obviously the advantage of this form of construction enables a much lighter, and less expensive structural member to be formed without compromising its capacity. The metal sheets for all aspects of the invention may be very thin gauge, ranging in thickness from 0.03 mm, thus reducing C02 output and building costs. -6- Once the structural elongate element is formed the base of each indentation of the first metal sheet may be in engagement with an inside face of the second metal sheet. The base of each indentation may be fixed to the inside face of the second metal 5 sheet. This may be by welding This further adds strength to the structural member. In another aspect of the invention the second sheet may also incorporate the strengthening means. In yet further aspects there may be multiple metal sheets incorporating 10 strengthening means such as bracing and/or indentations, to construct the structural elongate element . Once the structural elongate element is formed the base of each indentation of the first metal sheet may be in engagement with an inside face of another metal sheet, or may be in engagement with a base of an indentation on the other metal 15 sheet. The structural member may provide a lintel, I-beam, T-section, Z-section, C section or similar. In one aspect of the invention the structural elongate element may comprise a single metal sheet as hereinbefore described, whereby the indentations are 20 positioned such that once the structural elongate element is formed a portion of the convex surface of the at least one indentation is in engagement with a portion of the convex surface on a further indentation. In this manner the indentations supports the structure such that the metal sheet cannot be bent beyond the point which the indentations engage. 25 The structural member may comprise further members, such as a metal plate secured thereto. The plates may be used to tie the structural member into brick work. The invention provides a section comprising one or more fitted sheets to form a hollow construction. The first and second sheets may be joined to form a 30 structural member with at least one sheet having strengthening means such as internal bracing or indentations, and the other comprising a flat sheet. The section -7may also be formed by folding a flat sheet having previously punched indentations across a surface of the flange. The present invention provides a structural member comprising at least one hollow structural elongate element configured by joining a flat sheet and an 5 strengthening sheet, and a corrugated elongate element formed from a single corrugated sheet having a corrugated profile, the corrugated elongate element is placed centrally along the structural elongate element, a angled edge of an angled tie is formed by bending or folding the edge of the structural elongate element 0.02-2 centimetres at a 450 angle for fixing the corrugated elongate 10 element thereto. This construction will prevent bending moments occurring in the corners. Thus the angled tie will transfer stress away from the corners and disperse across the flanges. These aspects of the invention will produce a section of superior performance. In another aspect the angled edge of the angled tie may emanate from the fold of 15 one or both sheets of the structural elongate element. In other situations the angled tie may extend at an angle greater or less than 45* the width of which matches the pitch of the corresponding corrugated elongate element. The advantages of this invention are found in providing a reinforced hollow 20 section suitable for forming a wide range of structural members and other applications. The present invention provides a reinforced structural elongate element further strengthened by an angled tie formed from a fold in the flat sheet of the structural elongate element, the angled tie joined to the elongate element by fixing thereon. 25 The elongate element may be the corrugated elongate element. The angled tie may be joined to the corrugated elongate element by, but not restricted to the following methods: welding (spot, electrical resistance) soldering, gluing, lock seaming, or by using mechanical fasteners including, but not restricted to rivets, screws and nails. 30 The corrugations consist of an arrangement of square shaped gutters and ridges running in a vertical fashion. Importantly the corrugations comprise a mitred -8remote edge creating a unique fixing system to the angled tie. During construction, the corrugation may be filled with mortar, to link the structural element into the composite member. In such an application the structural element acts as a shear key. 5 Preferably the depth of each fold is pre-calculated to be within the range of .05 30 centimetres, but may also fall outside either side of this range. The corrugated elongate element may be fixed to the angled tie by welding continuously along the entire length of the member, In particular, at each mitred corner and between the corrugations to ensure a secure bond. 10 The weld may be continuous, essentially covering the area around the entire perimeter of the mitres including all the corrugated gutters and ridges. In other applications the weld may occur in specific points concentrating on the mitred corners and selectively spot welding the perimeter around the corrugated elongate element. 15 The angled edge of the angled tie provides superior strength to the section as load is transferred away from the corners and absorbed by the flange on either side eliminating any weakness at that point. The width across each fold is pre-calculated according to intended outcome, most commonly 1-20 centimetres, but may fall outside either side of this range. The 20 pattern of the corrugations may differ across the structural section to incorporate intervals of varying widths and depths. The pitch of the mitred corners may be slightly curved and pronounced in shape due to the effect of cutting the planes of the corrugated sheet which forms the corrugated elongate element, resulting in an effective fixing point to the angled 25 edge of the angled tie. The mitred fold of the corrugations occurs at the remote end of each corrugation and serves to strengthen the sheet by preventing bending moments weakening the section. The mitred folds positioned remotely at the ends of the corrugated sheet are fixed 30 to the sloped edge of the angled tie by welding or other means (noted previously within this invention). -9- The result of forming corrugations is a profile having ridges and gutters in a squared shape. The lateral sides may have less width than the main face, but, the reverse can also be obtained and is dependent on intended outcome. The structural member may have further elements, such as a metal plate used to 5 tie the structural member into brick work. The structural member may have slots or holes in the web or flanges to permit entry of other ties to secure to brickwork or other. The present invention provides a reinforced sheet of material comprising strengthening means, one of the strengthening means being the mitred ends of a 10 corrugated elongate element existing specifically to increase the strength of the sheet by reducing bending moments. The structural member may incorporate a web The web may encompass corrugations. The inclusion of corrugations with a mitred end at the remote edge of the web significantly reduces buckling and increases strength thereby providing 15 the capacity to create a larger range of products for the building industry having increased inherent strength, reliability and performance characteristics. The pitch, depth and width of the corrugations may vary across the same sheet. The sheet may encompass a multiplicity of corrugations differing in depth and width positioned in a spaced arrangement in straight lines to absorb load and 20 increase strength of the section. Preferably the distance between the corrugations is predetermined to reduce section buckling. This invention is also suitable for doors, panels and other light weight applications across many industries, such as. automotive, aeronautical, cycling, construction. 25 In one aspect of the invention the indentations may be filled with a concrete and/or mortar type mix to create a composite section. In another aspect the composite section may incorporate the brickwork or concrete walls, floors etcetera. During construction, the corrugations may be filled with mortar, to link the structural element. In such an application the structural 30 element acts as a shear key. -10- The present invention provides a reinforced sheet of material comprising strengthening means, the strengthening means being in the form of bracing or indentations incorporated in the sheet to increase the strength of the sheet, one or more strengthening means being placed in a specific arrangement including mid 5 span on the fold to enable the production of various types of structural members from the sheet. Such a structural member may incorporate a web. The addition of midspan indentations supports the web of the section significantly by reducing deformities and stiffness to the section, thereby providing the capacity to create a larger 10 range of products for the building industry having increased inherent strength, reliability and performance characteristics. The invention uses a truss like load action to allow the transfer of load from a state of tension to a state of compression across the sheet, resulting in a reduction of stiffness, thereby improving the capacity of the section. 15 The incorporation of a large number of indentations in the sheet inhibits buckling of the sheet. The sheet may be thin, preferably between 0.35 - 10 mm; however, thicker or thinner sheets may also be used. Preferably the indentations are placed symmetrically or in a random pattern 20 across and along the entire surface of the sheet in a predetermined pattern. The indentations may comprise a circular depression and may be punched, formed or depressed by other similar mechanical means to a predetermined depth into the sheet. Preferably the indentations will be a pre-determined size in circumference 25 dependant on the section being formed. According to this invention the fold line is predetermined and dependent on the end application and indentations will be formed in a symmetrical line either side of the fold line, in adjacent proximity so as to be spaced in two parallel lines. The two parallel lines of indentations arranged symmetrically along both sides of the fold 30 line strengthens the sheet. - 11~- In a number of applications the indentations may be placed along the centre line of the fold in a symmetrical pattern, adjacent to one another. A plurality of indentations may also be positioned in a predetermined arrangement across the reinforced sheet in spaced relation, preferably in straight lines but may 5 also be randomly spaced, or a combination of both. Preferably the distance between the indentations is predetermined. Dependent on the specific application the interval between the indentations will be predetermined to reduce the incidence of buckling while simultaneously increasing the strength of the sheet. 10 The reinforced sheet may be joined using, but not restricted, the following methods, spot welded, electrical resistance welding, welded, soldering, gluing, lock seaming, or other mechanical fasteners, including, but not restricted to, rivets, screws and nails. The specific mid-span position having the indentations allows loads to be resolved 15 to both faces of a hollow section, as the indented corners can absorb a greater load, thereby increasing the inherent overall strength and performance of the section. Transfer of loads within the perimeter of the structural member reduces the stress created by loads on any specific joint area. This reduction enhances the overall 20 strength and performance of the structural member. This invention is suitable for doors, panels and other light weight applications across many industries, i.e. automotive, aeronautical, cycling, construction etc. According to another aspect of the invention the structural member is formed from one or more structural elongate elements, the structural elongate elements are 25 formed by welding one or more sheets together, at least one of the sheets have a plurality of indentations adjacent to, or in engagement with, the portion which will be welded to another sheet. Welding at the point of the indentations will significantly improve the performance of the section. In one aspect of the invention the indentations may be filled with a concrete 30 and/or mortar type mix to create a composite section. -12- In another aspect the composite section may incorporate the brickwork or concrete walls, floors etc. The structural member may also have a one or more continuous channels extending along the length of the top and bottom longitudinal lip/edge which may 5 receive a portion of the concrete mix to increase the bond strength of the formed composite section. The one or more channels may be first formed symmetrically along the longitudinal length of the lip/edge of the sheet, and may be of various depths, widths and spacing. 10 In another aspect, the sheet may also incorporate additional ripples, corrugations and other shaped indentations along its longitudinal rim or edge. The channels, ripples and corrugations may be formed mid-span at the position of fold to increase strength and performance Ripples, corrugation, channels or indentations may be positioned in a 15 predetermined pattern, in close proximity to one another on the surface of the sheet to improve shear strength capacity. The invention improves the strength and performance of a planar sheet of material thereby providing a reinforced sheet which may be used to manufacture a wide range of structural members on a more cost effective basis. Several 20 benefits of the current invention are outlined below: - provides a sheet of increased strength which can be used for a wide range of applications, for example, I, Z, T, L and C metal sections, flat panels, circular and other shaped hollow tubing. By placing indentions along the median of the sheet at the fold or bend lines the inherent strength of the 25 sheet is increased. Furthermore, having the indentations placed at close proximity from one another increases the strength, performance and cost effectiveness of the sheet of material; - enables transfer of load between a state of tension and compression due to the dimples I indentations resulting in a reduced incidence of buckling 30 and a section with increased strength; - 13 - - inhibits buckling and strengthens the sheet allowing lightweight and slender structural members to be formed; - enables a variety of jointing procedures to be utilised to form the intended structural member: spot welding, electrical resistance welding, welding, 5 soldering, gluing, lock streaming and a range of mechanical fasteners; - enables the indentations to act as a shear connector when used within a composite section as the indentations increase the surface area of the sheet; - where the indentations are filled with a concrete/mortar type or other similar 10 mix the invention enables an increase in the transfer of shear flow from the indented section to the adjoining brickwork or concrete slab; - permits further indentations such as the continuous channels which increases the bond strength of the composite materials; - permits additional ripples, corrugations or alternative indentations to be 15 added to the surface exposed to the composite face to improve shear strength capacity; - enables a variety of structural members to be formed that are substantially lighter in weight to current models, thereby, reducing cost to the builder and the incidence of injury to workers lifting the structural members; 20 - the angled tie prevents bending moments developing in the corners of the flange and restrains local stresses under compression and tension resulting in reduced incidence of buckling and a section with increased strength; - a corrugated web placed either midspan or along the edge of an indented 25 sheet provides a section with increased strength, by inhibiting buckling; - the mitred edges of the corrugated web prevents bending moments thereby reducing buckling and increasing section strength; - a variety of jointing procedures may be utilised to construct the intended structural member: welding (electrical resistance, spot), soldering, gluing, 30 lock streaming and a range of mechanical fasteners; - 14 - - the indentations act as shear connectors in a composite section when filled with a concrete mix resultantly increasing the surface area of the sheet. The current invention is sufficiently flexible to allow for new designs or improved designs for structural members to be created to suit most structural building 5 needs. The current invention may also be employed to formulate other technology like bicycle parts, door or other panels, interior lining etc for a wide variety of applications across many industries. Brief Description of the Drawings 10 The invention will be better understood by reference to the following descriptions of several specific embodiments thereof as shown in the accompanying drawings in which: FIG 1 is a top view of a reinforced sheet incorporating a plurality of indentations along a fold line according to a first embodiment of the 15 invention; FIG 2 is a top view of a reinforced sheet incorporating a plurality of indentations along a fold line according to a second embodiment of the invention; FIG 3 is a perspective view of a hollow L-section (lintel), formed in part 20 from the reinforced sheet shown in figure 1; FIG 4, 5 and 6 depict the method of forming the hollow L-section shown in figure 3; FIG 7 is a cross sectional view of the invention showing how force is transmitted in a truss like fashion to reinforce the corners; 25 FIG 8 is a cross sectional side view of an I-section formed from several reinforced sheets according to an embodiment of the present invention; FIG 9 is a view similar to figure 8 but having an increased web thickness; FIG 10 is a cross sectional side view of a Z-section formed from several reinforced sheets according to an embodiment of the present invention; -15- FIG 11 is a view similar to figure 10; FIG 12 is a cross sectional side view of a C-section formed from several reinforced sheets according to an embodiment of the present invention; FIG 13 is a cross sectional side view of a composite section according to a 5 further embodiment of the invention; FIG 14 is a cross sectional side view of a T-section formed from several reinforced sheets according to an embodiment of the present invention; FIG 15 is a view similar to figure 14 but having an increased web thickness; FIGS 16, 17 and 18 are views similar to figure 3 further including channels 10 and/or recesses formed along the edge of the section according to a further embodiment of the invention; FIGS 19 is a cross sectional side view of a C-section formed from a reinforced sheet according to an embodiment of the present invention; FIG 20 is a cross sectional side view of a Z-section formed from a 15 reinforced sheet according to an embodiment of the present invention; FIG 21 is a front view of figure 6. FIG 22 is a side view illustrating an indented hollow flange section having a sloped edge extending into an angled tie for joining to the corrugated web, thus resulting in a typical lintel according to the first and second 20 embodiments of the invention; FIG 23 is a cross sectional view of figs 22 and 25; FIG 24 and 26 are cross sectional views depicting the profile of the corrugations in the web in figures 22 and 25; FIG 25 is a side view of the hollow section, similar to fig 22 presenting an 25 alternative pattern in the corrugated web and showing the angled tie extending from the flange to the web according to the invention; FIG 27 is a side view of a hollow T section portraying a centralised corrugated web fixed to indented flanges the sloped edge of which extends into an angled tie according to the first embodiment; -16- FIG 28 is a cross sectional side view of fig 6 illustrating the profile of the corrugations used; FIG 29 is a side view of an I beam comprising reinforced sheets to form a hollow section and fixing the angled tie to the centre web at each end 5 according to an embodiment of the invention; FIG 30 is a cross sectional side view of figure 8 showing the section profile; FIG 31 is a side view of a C beam illustrating further use of the reinforced sheets to comprise a hollow section according to the invention; FIG 32 is a cross sectional side view of a C-section showing the profile of 10 the corrugated sheet; FIG 33 is a side view of a Z beam and represents the flexibility of the invention to create various reinforced hollow sections according to the invention; FIG 34 is a cross sectional side view of the profile of the Z beam in figure 15 33; FIG 35 is a side view of a box configuration illustrating the use of the reinforced hollow section according to the aforementioned principles of this invention; FIG 36 is a cross section view and depicts the profile of the box 20 configuration in fig 35; FIG 37 illustrates alternative angled and curved corrugations for the purposes of the web In this invention; FIG 38 is a side view of a typical hollow lintel and shows a close up view of the sloping edge of the angled tie formed from the flange and the location 25 of the weld for corrugated web to be fixed thereon; FIG 39 is a diagram depicting the forces of tension and compression. At the location of the angled tie and corrugated web tension and compression are dispersed from the corner to the flanges eliminating any weakness at this point; -17- FIG 40 is a front perspective view illustrating a braced hollow flange section having a sloped edge extending into an angled tie for joining to the corrugated web, thus resulting in a typical lintel according to the first and second embodiments of the invention; 5 FIG 41 is a rear perspective view of the hollow section shown in fig 40; FIG 42 is a cross sectional view of figs 40 and 41; and FIG 43 is a is a cross sectional side view of a composite section incorporating the hollow flange section of figures 40 to 42. In the drawings like structures are referred to by like numerals throughout the 10 several views. The drawings shown are not necessarily to scale, with emphasis instead generally being placed upon illustrating the principles of the present invention. Best Mode(s) for Carrying out the Invention The reinforced sheet 5 of the present invention may typically be provided by 15 forming incorporating strengthening means such as bracing or a plurality of indentations, (e.g. semi-spherical indentations 3), in a substantial planar sheet of material. The reinforced sheet 5 may then be used to form a structural member 111 such as an L, Z, 1, C or other section. 20 In one embodiment the position of the plurality of indentations 3 is dictated by the structural member 111 which will be made from the reinforced sheet 5. Generally the structural member 111 may be formed by folding (or bending) the reinforced sheet 5 about one or more fold lines 1. The reinforced plate 5 is formed from hot or cold-formed steel and may be any 25 thickness, but is commonly in the range of 0.35 - 5 mm. There are no restrictions on the width and length of metal sheets when forming indentations 3 according to this invention. Other suitable materials include aluminium, titanium, any structural plastic, manufactured or natural timber. In a first embodiment, as shown in figure 1 the indentations 3 have a periphery 30 103 which is common with/engages the fold line 1. -18- In a second embodiment, as shown in figure 2 the indentations 3 have a periphery 103 which is spaced from the fold line 1. To accommodate the fold in a manner which will ensure the structural member 111 will retain the same or similar strength characteristics as the reinforced sheet 5 5, a row of spaced indentations 3 are formed in the sheet either side of the fold line 1. The reinforced sheet 5 may also incorporate indentations 3 across other parts of the sheet, as shown in figure 1. The reinforced sheet 5, or a combination of one or more of the sheets, once 10 folded may be used to form various structural members 111. The formed structural members 111 are of hollow construction with the indentations extending into the hollow section. Figures 4 to 6 depict the formation of an L-section. In order to form the L-section a first sheet in the form of the reinforced sheet 5, is folded about fold line 1. A 15 second sheet, in the form of a planar sheet 106 is also folded in a complementary fashion. The two sheets may then be fixed together, as shown in figure 6, such as by welding to form an L-section structural member 111. In an alternative L-section 111 the first sheet may be a planar sheet 106 whilst the second sheet is formed from the reinforced sheet 5. 20 To increase the strength of the structural member 111, the base 113 of each indentation 3 engages the inside face 115 of the second sheet 106. To further increase the strength the base may be welded to the inside face 115. Figure 3 shows an L-section similar to that shown in figure 6 further comprising a shear connector plate 49 which is positioned so that in the construction of a wall it 25 will be received in a mortar joint. Figure 7 illustrates how the indentations 3 allow force to be transmitted in a truss like fashion to reinforce the corners 13. Figures 8 to 21 provide representations of various structural members 111 formed from one or more sheets of material in accordance with embodiments of the 30 present invention. - 19 - Figures 8 and 9 show two models of an I-beam 25. Figure 9 further shows an I beam 25 having a double web made by fixing two reinforced sheets 5 in back to back orientation The I-beam is further strengthened by welding the base 113 of corresponding indentations together. 5 Figures 10 and 11 represent two typical Z sections 27. The indentations 3 are arranged in the corners of the fold 1. Figure 10 has a double top flange (with the base 113 of corresponding indentations 3 welded together) and a single bottom flange as a variation to figure 11, thus depicting the flexibility of the invention. Figure 12 depicts a C section 29 whereby the arrangement of indentations 3 10 reinforces the corners of the fold 1. In this instance the C section 29 has single flanges and web, however, this may be modified, as in figure 10, to suit the application. As can be shown in figure 13 a composite section 33 may be created to further strengthen the indented metal section 23. Figure 13 illustrates a composite 15 section 33 having a lintel 43 fixed in brickwork 35 to create a composite section of improved strength. In this design the presence of the indentations 3 will increase the strength and function of the lintel 43 improving overall performance. In a composite section 33 the indentations 3 are specifically filled with mortar 17 to secure overall strength and performance. 20 Figures 14 and 15 show a typical T section 31, having indentations 3 along the web and flanges and in the fold 1. Figures 16, 17 and 18 provide examples for the profile of a continuous channel 47 formed along the length of the edgellip of the structural member 111. The continuous channel 47 further enhances the composite action of the section when 25 filled with mortar 37. Figure 19 illustrates a structural member 111 formed from only a reinforced sheet 5. With this member 111 a portion of adjacent indentations 3 engage and are fixed together to reinforce the corner 21 of the section, preventing subsequent buckling formed at the fold 1, and to strengthen the section. 30 Figure 20 shows how indentations can intersect one another 21 in the fold to strengthen and create a section with increased performance and flexibility. -20- A series of holes or loops (not shown) can be fitted to various angles of the section to later fix tie downs straps etc. In a further embodiment, as shown in figure 22 the hollow section has a corrugated web 5 depicting an arrangement of evenly spaced vertically positioned 5 corrugations 7 having a shorter depth than width. The corrugations 7 are formed by mechanically bending the corrugated sheet 5 to form a series of square shaped ridges and gutters The corrugated web 5 is formed from hot or cold formed steel and may be any thickness, but for the purposes of describing this invention in the range of 0.03 - 5 10 mm. Length and width of the metal sheets can vary in size and other materials may be used to form the section (for example, aluminium, plastics, timber and other metals). At each remote edge of the corrugations 7 is a mitred corner 9. The base of the 15 mitred corners 9 are fixed to the sloped edge of the angled tie 11. Due to the 45 degree angle of the sloped edge of the tie on the hollow flange 27 as can be seen in figure 25, and the profile from cutting the 3 sides of each corrugation 7 a secure fit and join is achieved. The join occurs by welding 19 these points to form a section of great strength. The width of the sloped edge of the angled tie 11 20 matches the pitch of the corrugations 7 on the web for a superior join. In a further embodiment, as shown in figure 25 the corrugations 7 have a wider spacing. Alternatively the pattern of corrugations 7 can vary in size, number, width and depth within the same sheet 5 as shown in figs 24, 28, 30 and 37. The combination of the sloped edge of the angled tie 11 and the profile of the 25 corrugations 7 prevents bending moments occurring in the corners as load is transferred away from this point to the larger flanges 27. The reinforced sheets I and 5 or a combination of one or more of the sheets, once folded may be used to form various structural members 25. The formed structural members 25 are of hollow construction with the indentations extending 30 into the hollow section. The sheets 1 and 5 are butt joined or seam lapped in a position remote from the angled tie. -21- A series of holes or loops (not shown) can be fitted to various angles of the section to later fix tie downs straps etc. Figure 27 depicts a typical T section. According to the invention the T section is constructed by joining a hollow flange 27 with an angled tie 11 to a corrugated 5 web 5. The hollow section 25 may consist one indented sheet 1 and one corrugated sheet 5, or alternatively 2 indented sheets I joined. To increase the strength of the structural member 25, the base 31 of each indentation 3 engages the inside face 33 of the flat sheet 23. To further increase 10 the strength the base may be welded 19 to the inside face 33. Figure 29 is a model of an I beam with two hollow flanges 27 having a corrugated web 5 fixed centrally between their planar surfaces. Fixed according to the invention along the sloped edge of the angled tie 11 formed along the flange 27 15 for joining the corrugations 7 longitudinally along both top and bottom and both sides. The -beam is further strengthened by welding the base 31 of the corresponding indented and flat surfaces together across the apex of the indentations. Figures 31 and 33 represent how the invention can be configured into various 20 other commonly used sections showing a hollow C section (fig 31) and a hollow Z section (fig 33). These illustrations modelling a centralised corrugated web 5 strengthened further with top and bottom indented flanges 27. Figure 35 is a cross sectional rear view of a box configuration used for specific applications in the building industry. This section has a centre indented sheet 1 25 forming a web with single thickness and corrugated flanges 27 adjacent to one another on the lateral edges either side of the web. In this instance the indented web 1 may also be filled with concrete thus creating a composite section due to the interaction between the indented steel sheets 1 topped with a concrete mix. Figure 38 depicts a close up view of a typical hollow section 25 showing the fold 30 lines 21 of the hollow flange 27. The fold lines 21 occurring where the flange 27 meets the corrugated web 5 are forming the sloped edge of the angled tie 11. -22- The tab of the mitred corners 17 resulting from the corrugations 7 is pronounced, the pitch of which meets the sloping edge of the angled tie 11 to create a single compression load. Weld 19 is applied to join the tab of the mitred corners 17 to the angled tie 11, 5 The lip edge 13 of the web 5 prevents compression and tension of the web to provide a section of great strength. Figure 39 shows the angle of tension and compression forces collecting at the corner of the section. The sloping edge of the angled tie and the corrugated web prevent weakness at this point as tension and compression are dispersed to the 10 flanges. As shown in figures 40 to 43 the strengthening means is n the form of a brace 203 which runs the length of the elongate element. The brace is internal and extends between the internal surfaces of the hollow section. The brace is formed form the single sheet material used to construct the hollow section, being formed at the 15 beginning or end of the bending process. The invention provides 1) The angled tie allows the transfer moment (or tension compression loads) from the top and bottom surfaces of the hollow section to each face of the attached (welded) corrugated web; 20 2) the corrugated web allows for the each open corrugated face to be mortar filled, creating a shear transferring bond between the brickwork and the mortar, creating a composite section; 3) the brace provides a figure 8 configuration of the bottom hollow section, this stiffens the section against local and distortional buckling and reducing deflection 25 of the top and bottom skin relative to each other.. Also notable is the texture of the galvanising finish on each sheet which is due to the methodology used in galvanising; resulting in several outcomes inherent to this process: 6 provides a nonslip surface preventing the possibility of the 30 internal rendered walls and cornices cracking when the metal is under expansion and contraction; -23 - 0 ready to paint surface leaving a smooth top finish which requires minimal painting and leaves a pleasing aesthetic finish; * model is easily distinguishable from comparable products on the market; 5 rougher surface results in easier grip and less likelihood of slipping when being unloaded or lifted into position (particularly on longer length sections). Modifications and variations such as would be apparent to the skilled addressee are considered to fall within the scope of the present invention. Throughout the specification, unless the context requires otherwise, the word 10 "comprise" or variations such as "comprises" or "comprising" will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers. Also, future patent applications maybe filed in Australia or overseas on the basis of, or claiming priority from, the present application. It is to be understood that the 15 following provisional claims are provided by way of example only, and are not intended to limit the scope of what may be claimed in any such future application. Features may be added to or omitted from the provisional claims at a later date so as to further define or re-define the invention or inventions. - 24 -