Patent Publication Number: US-2020283980-A1

Title: Support member

Description:
TECHNICAL FIELD 
     The present invention relates to a support member. In some embodiments of the specification, the support member comprises a support member that is driven into the ground to provide at least part of the foundation structure. 
     BACKGROUND ART 
     Screw piles are used in the construction of buildings and other structures. A typical screw pile comprises a shaft, normally made from mild steel or a higher strength steel. A helical screw or blade is attached to the shaft. In order to insert the screw pile into the ground, the screw pile is rotated and pressed downwardly which causes the helical blade to bite into the ground and to screw into the ground. Once the screw pile has been properly inserted into the ground, the weight borne by the screw pile is distributed from the helical blade into the earth that lies underneath the helical blade. Further, the earth positioned above the helical blade assists in resisting any lifting forces applied to the screw pile and thereby assists in maintaining the screw pile in the ground. 
     Conventional screw piles comprise a single helical blade. The blade has a leading edge that moves through and breaks the earth as the screw pile is screwed into the ground. Conventional screw piles have a leading edge on their blade that extends generally perpendicularly to the outer periphery of the blade (when viewed from above). As the shaft is normally cylindrical in shape, the leading edge of the blade may be considered to extend outwardly from the shaft in the radial direction. 
     Australian patent application number 2010202047 and Australian innovation patent number 2011100820, the entire contents of which are herein incorporated by cross-reference, describe a screw pile comprising a shaft, at least two blades extending outwardly from the shaft, each blade having a leading edge that contacts earth as the screw pile is screwed into the ground, the leading edge including at least a portion extending in a direction that is non-perpendicular to an outer periphery of the shaft (when viewed from above). 
     Alternatively, the screw pile described in that patent application and innovation patent comprises a screw pile comprising a shaft, at least two blades extending outwardly from the shaft, each blade having a leading edge that contacts earth as the screw pile is screwed into the ground, the leading edge including a swept back portion adapted to deflect rocks that come into contact with the swept back portion of the leading edge during insertion of the screw pile into the ground. The screw pile may comprise two blades in the form of angled plates. The angled plates may be mounted to the shaft. The angled plates may be mounted to the shaft, for example, by welding. Alternatively, the angled plates may be integrally formed with the shaft. The angled plates may be generally flat angled plates. The angled plates may have opposite pitch to each other. For example, when viewed from side on, one angled plate may extend downwardly from left to right while the other angled plate may extend downwardly from right to left. 
     Using angled blades instead of a helical screw makes manufacture of the screw pile more simple. Further, each angled blade counteracts the forces applied by the other angled blade during insertion of the screw pile, thereby resulting in the screw pile being easier to install. 
     Large-scale solar energy installations typically comprise a number of solar photovoltaic cells or solar collectors (such as solar collectors that are used to heat water to produce steam). In some solar energy installations, the solar photovoltaic cells or solar collectors track the sun during the day in order to maximise the amount of solar energy collected. In order to achieve this, some installations mount a number of solar photovoltaic cells or solar collectors to large drive beams and the drive beams are slowly rotated during the day to track the movement of the sun. The drive beams and associated structure must be firmly mounted in the ground a number of locations in order to firmly support the drive beam to stop or minimise distortion of the drive beam during use. Some large-scale solar energy installations mount the supporting structure for the drive beams to concrete foundations whilst other large-scale solar energy installations utilise screw piles. 
     Low strength soil sites pose extreme challenges in finding sufficient lateral load in the upper layers to support solar farm arrays during high winds and/or mechanical moments generated by sun tracker system drive motors. Very deep driven beams are commonly required to satisfy the required loads. Further, due to the low geotechnical strength of the soil, bending moment loads extend down the length of the beam, forcing increases in beam size, installation time and cost. 
     Conventional driven beams are typically slender steel columns driven into the ground. Due to their slender design and therefore limited surface area, they need to be driven deep into the ground to create sufficient skin friction area for compression and tension load requirements. Driven beams founded at greater depth leads to prolonged installation time, which can lead to excessive drive hammer damage to beam tops and a higher likelihood of encountering unidentified obstacles at a greater depth, such as floaters, rock layers, hard gravel layers and the like. 
     It will be clearly understood that, if a prior art publication is referred to herein, this reference does not constitute an admission that the publication forms part of the common general knowledge in the art in Australia or in any other country. 
     SUMMARY OF INVENTION 
     The present invention is directed to a support member, which may at least partially overcome at least one of the abovementioned disadvantages or provide the consumer with a useful or commercial choice. 
     With the foregoing in view, the present invention in one form, resides broadly in a support member comprising a beam adapted to be driven into the ground, and one or more wings extending generally transversely outwardly from the beam. 
     In one embodiment, the one or more wings may be in the form of plates extending transversely to the beam. The wings may have an outer edge that extends in a direction that is generally parallel to a longitudinal axis of the beam. In one embodiment, each wing extends in a plane that is parallel to a longitudinal axis of the beam. 
     In one embodiment, the one or more wings may have lower edges that extend at an acute angle to the longitudinal axis of the beam, thereby assisting penetration of the leading edge of the one or more wings into the ground. 
     A plurality of wings may be provided. 
     In one embodiment, at least some of the wings are located such that when the beam is driven into the ground to a desired depth, the one or more wings are wholly located below ground level. 
     In one embodiment, the one or more wings comprise a first set of wings located at a first region and a second set of wings located at the second region, the second region being spaced along the beam from the first region. In some embodiments, the wings in the first set of wings may be of a different size to at least one of the wings in the second set of wings. 
     In one embodiment, the beam may comprise an I-beam or a C-beam or a H-beam. The skilled person will understand that an I-beam and a H-beam comprises a central web having flanges extending from the central web. Each flange extends to both sides of the central web. A C-beam also has a central web with flanges extending from the central web. However, the flanges of a C-beam only extend to one side of the central web, thereby giving a C-shaped cross-section to the beam. In other embodiments, the beam may comprise a rectangular hollow section (RHS) beam. 
     In one embodiment, at least one of the one or more wings is welded to the beam. The present inventors believe that by welding the wings to the beam, increased stiffness is provided to the beam. In an advantageous embodiment, at least one of the one or more wings is welded to the beam in a manner such that a face of the wing is in abutment with a face of the beam. 
     In one embodiment, the beam comprises an I-beam or a H-beam and at least one of the wings is welded to a flange of the I-beam or H-beam. In one embodiment, the at least one wing comprises a first wing welded to a flange on one side of a central web of the beam and a second wing welded to a flange on another side of the central web of the beam. 
     In one embodiment, the beam comprises an I-beam or a H-beam and at least one wing is welded to an inside face of a flange of the H-beam or I-beam, wherein a face of the wing is in abutment with an inside face of the flange of the beam. This advantageously stiffens the beam. 
     In one embodiment, the beam comprises an I-beam or a H-beam and the one or more stabilising wings comprises a pair of stabilising wings, with a first wing of the pair being welded to an inside face of a flange of the beam and a second wing of the pair being welded to an inside face of the flange on an opposite side of the central web of the beam. 
     In one embodiment, the at least one stabilising wing comprises a second pair of stabilising wings located towards a lower end of the beam, the second pair of stabilising wings being spaced from a first pair of stabilising wings. 
     In one embodiment, the beam comprises an I-beam or a H-beam and the second pair of stabilising wings comprises a first wing of the pair being welded to an inside face of a flange of the beam and a second wing of the pair being welded to an inside face of the flange on an opposite side of the central web of the beam. 
     In another embodiment, the support member may comprise a further stabilising wing attached to and extending transversely from a flange or a face of the beam. 
     In one embodiment, the beam has a lower end that is shaped to facilitate insertion or driving of the beam into the ground. In one embodiment, the lower end of the beam comprises a sharpened point or a sharpened apex. In one embodiment, the lower end of the beam has a V-shape. In one embodiment, the lower end of the beam is delta cut to facilitate improved installation into the ground. 
     In one embodiment, the support member is provided with one or more receptacles to receive soil or earth when the support member is inserted into the ground. The one or more receptacles may include at least one upwardly and outwardly extending wall. In some embodiments, the one or more receptacles have a lower opening in a lower part to allow soil to enter into the receptacle through the opening during insertion of the support member into the ground. The lower opening will also allow water to drain from the one or more receptacles, thereby preventing or minimising the risk that water will be retained in receptacles. 
     In one embodiment, the one or more receptacles have an upper opening and a lower opening, the opening being larger than the lower opening. 
     In one embodiment, a receptacle is formed by positioning a plate between flanges of the beam, the plate being angled outwardly and upwardly relative to a longitudinal axis of the beam. In one embodiment, the plate is welded to each of the flanges. In one embodiment, an inner edge of the plate is spaced from the web of the beam to thereby form a lower opening between the web and the inner edge of the plate. 
     In embodiments where one or more plates are joined to the beam, the number, size and shape of the plates can vary and are dependent upon the required load and geotechnical strength. 
     In some embodiments, the one or more plates do not extend beyond outer edges of the flanges. It is believed that this will reduce the likelihood of bending or damage to the plates as the support member is inserted into the ground. In other embodiments, the one or more plates may extend beyond the outer ends of the flanges, particularly if the support member is to be used in very friable or easily displaced soil. 
     In a second aspect, the present invention provides a support member comprising a beam adapted to be driven into the ground, and one or more receptacles to receive soil or earth when the support member is inserted into the ground. The beam may comprise a web having flanges extending from the web and the one or more receptacles may be located between the webs. In one embodiment, a receptacle is formed by joining and upwardly and outwardly angled plate to the one or more webs. 
     Other features of the one or more receptacles may be as described with reference to the first embodiment of the present invention. 
     It is believed that the one or more receptacles will fill with soil or earth when the support member is inserted into the ground. This should then provide greater resistance to upward movement of the beam, which should assist in retaining the beam in its desired position within the ground. 
     Without wishing to be bound by theory, the present inventors believe that when the support member is inserted or driven into the ground, the one or more wings mobilise a greater soil area in the vicinity of the wings, thereby providing a substantial increase in “skin friction” surface area to satisfy both compression and tension load requirements of a given project. The present inventors also believe that the support members of the present invention can be shorter than a conventional driven beam, thereby reducing cost and making installation easier. 
     The support members of the present invention are particularly useful for forming part or all of the foundation structure in sandy soils or weak soils. The support members of the present invention are particularly useful for forming foundation piles for solar arrays. The wings greatly reduce the potential for geotechnical failure (soil shear) under load while storing elastic geo-energy to ensure that the members rebound to vertical after extreme loads are applied. These elements directly benefit the solar arrays attached to the top of the members, because the members/soil partly act as lateral shock absorbers to smooth out wind loads and reduce shock forces from sharp spikes in high wind conditions. Further, as the wings can assist in strengthening the beam, it is possible to use a lighter gauge beam, thereby reducing cost. Further, a shorter beam can be used, when compared with conventional beams, again reducing cost and easing installation. Further, as shorter beams can be used, the likelihood of damage to the top of the beam from the hammer or pile driver is minimised. 
     Any of the features described herein can be combined in any combination with any one or more of the other features described herein within the scope of the invention. 
     The reference to any prior art in this specification is not, and should not be taken as an acknowledgement or any form of suggestion that the prior art forms part of the common general knowledge. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       Various embodiments of the invention will be described with reference to the following drawings, in which: 
         FIG. 1  shows a perspective view from one side of a support member in accordance with an embodiment of the present invention; 
         FIG. 2  shows a perspective view from another side of the support member shown in  FIG. 1 ; 
         FIG. 3  shows a side view of the support member shown in  FIG. 1 . The view of  FIG. 3  is taken from an aspect such that a flange of the beam can be seen; 
         FIG. 4  shows a side view of the support member shown in  FIG. 1 . The view of  FIG. 4  is taken from an aspect such that the full extent of a web of the beam can be seen; 
         FIG. 5  shows a top plan view of the support member shown in  FIG. 1 ; 
         FIG. 6  shows a bottom plan view of the support member shown in  FIG. 1 ; 
         FIG. 7  shows a side elevation (from the same aspect as shown in  FIG. 3 ) of the support member shown in  FIG. 1 , with  FIG. 7  diagrammatically showing the support member inserted into the ground; 
         FIG. 8  shows a similar view to  FIG. 7 , but taken from the aspect as shown in  FIG. 4 ; 
         FIG. 9  shows a diagrammatic side elevation of a 5.5 m conventional beam that has been driven 4 m into the ground; 
         FIG. 10  shows a diagrammatic side elevation of a 6.5 m beam that has been driven 5 m into the ground; 
         FIG. 11  shows diagrammatic views of interaction with the ground and lateral loads for a support member in accordance with an embodiment of the present invention and for a conventional steel driven beam; 
         FIG. 12  shows a perspective view of a support member in accordance with another embodiment of the present invention; and 
         FIG. 13  shows a side view of the support member shown in  FIG. 12 . 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     It will be appreciated that the drawings have been provided for the purposes of illustrating preferred embodiments of the present invention. Therefore, it will be understood that the present invention should not be considered to be limited solely to the features as shown in the attached drawings. 
       FIGS. 1 to 6  show various views of a support member in accordance with an embodiment of the present invention. The support member  10  shown in  FIGS. 1 to 6  comprises an I-beam  12 . The I-beam  12  has a central web  14 , a first flange  16  and a second flange  18 , as best shown in  FIGS. 5 and 6 . The I-beam is suitably made from steel and it may be galvanised for corrosion protection. 
     As shown in  FIGS. 1 to 4 , the support member  10  also includes two sets of wings. The first set of wings is positioned at an intermediate portion of the beam  12  and the second set of wings is positioned at a lower end of the beam  12 . 
     Throughout this specification the terms “upper” and “lower” are used to indicate the orientation of the support member when it is in its installed position in the ground. 
     The first set of wings comprises wings  20  and  22 . Wings  20 ,  22  are basically identical to each other. Wing  20  has a leading edge  24 , a side a  26  and a trailing edge  28 . Again, the terms “leading” and “trailing” are used with reference to the orientation that the support member adopts once it has been inserted into the ground. The leading edge  24  sweeps backward and upwardly at an acute angle, which assists in the wing penetrating the ground as the support member  10  is being driven into the ground. 
     As can be seen from  FIGS. 4 to 6 , the wing  20  is connected to the beam  12  by positioning the wing  20  such that a face of the wing  20  comes into contact with an underside of flange  18  of the beam  12 . Appropriate welds can then be used to connect the wing  20  to the beam  12 . For example, lines of weld metal can be positioned adjacent to regions where edges of the wing  20  are adjacent to the underside of flange  18  of beam  12  and where an inner edge of the wing  20  is adjacent to the central flange  14 . The wing  22  is similarly joined to the other side of flange  18  that lies on the other side of the central web  14 . 
     As can be seen in  FIGS. 5 and 6 , by joining the wing  20  to the underside of flange  18 , the effective thickness of flange  18  is increased, thereby increasing thickness of the flange and resulting in a significant increase in bending moment strength. A similar outcome would be achieved if the wing  20  was joined to the other side of the flange  18 . 
     The support member  10  shown in  FIGS. 1 to 4  also comprises a second set of wings that is positioned towards the lower end of the beam  12 . The second set of wings includes wing  30  and wing  32 . The wings  30  and  32  are joined to the underside of flange  18  in a manner that is similar to wing  20  being joined to the underside of flange  18 . As can be seen, the wings  30 ,  32  are smaller than the wings  20 ,  22 . The wings  30 ,  32  also have swept back or angled leading edges in order to facilitate penetration into the ground. 
     The flanges,  16 ,  18  at the lower end of the beam  12  are Delta cut in order to assist in penetration of the support member  10  into the ground. This results in the central web forming an apex  34  with the leading edges  36 ,  38  of the flanges being swept back at an acute angle. Effectively, as best shown in  FIG. 3 , the lower end of the support member  10  is generally V-shaped. 
     The first set of wings  20 ,  22  are located such that when the support member  10  is properly driven into the ground to the desired depth, the first set of wings are located wholly below ground level and with the top of the wings  20 ,  22  being located close to the soil surface. This is shown in  FIGS. 7 and 8 , where the soil level is shown at  40 . If a lateral load is applied to the top of the member, the first set of wings and the beam work together to raise to raise the effective pivot point, increasing turnover resistance with high levels of stored elastic energy, for maintaining the support member  10  in the desired vertical position even after a high wind or high frequency event. In this regard, the wings  20 ,  22  mobilise or engage with a large bulb of soil and can be effective in resisting lateral loads applied to the top of the support member  10 . 
     The second set of wings  30 ,  32  may not be required in all situations. However, where the second set of wings are present, the second set of wings  30 ,  32  also mobilise a bulb of soil near the lower end of the support member  10 . This also assists in maintaining the support member  10  in position when lateral loads applied to the top of the support member  10 . 
     In some embodiments, the width of the beam  12  is sufficient to resist twisting forces applied to the support member  10 . In this regard, the width of the beam  12  is effectively the height of the central web  14  of the beam  12 . However, in some embodiments, it may be desirable to include a further set of wings that are joined to the flanges  16 ,  18  and extend transversely to the flanges  16 ,  18 . With reference to  FIGS. 5 and 6 , these additional wings can be seen at  42  and  44 . Similarly, the wings  42 ,  44  can be clearly seen in  FIG. 8 . These wings may be joined to the respective flanges  16 ,  18  by running weld metal along the edges of the wings  42 ,  44  that are in abutment with the flanges  16 ,  18 . 
       FIGS. 7 and 8  show the support member  10  being positioned in the ground. The ground level is shown at  40 . In  FIGS. 7 and 8 , the region of soil that comes under the influence of the wings can be seen in the darker shaded background. 
       FIGS. 9 and 10  show a conventional steel driven beam being placed on the ground. In  FIG. 9 , the beam  50  is 5.5 m long and has been driven 4 m into the ground. In  FIG. 10  the beam  52  is 6.5 m long and has been driven 5 m into the ground. As can be seen by comparing  FIGS. 7 and 8  with  FIGS. 9 and 10 , the region of soil that “reacts” with the support member  10  shown in  FIGS. 7 and 8  is of similar size to the region of soil that “reacts” with the conventional beams  50 ,  52  as shown in  FIGS. 9 and 10 . However, the support member  10  shown in  FIGS. 7 and 8  is only 4.5 m long and has been driven 3 m into the ground, in comparison to the 5.5 m beam being driven 4 m into the ground in  FIG. 9  and the 6.5 m beam driven 5 m into the ground in  FIG. 10 . Therefore, a significantly shorter beam can be used to attain similar resistance to lateral loading by using the support member in accordance with embodiments of the present invention. 
       FIG. 11  also shows a similar comparison between a 4.5 m long support member that has been driven 1.5 m into the ground, with the top of the first set of wings being located 25 cm below soil level, with a 6 meter long conventional beam that has been driven 4.5 m into the ground. As can be seen, the first set of wings of support member  10  moves the pivot point to close to the top of the first set of wings, due to the large mobilised soil bulb that interacts with the wings  20 ,  22 . Accordingly applying a lateral load that forces the top of the support member  10  to the left causes the first set of wings to mobilise the soil bulb  60 , which resists the lateral load. It also moves the pivot point close to the region as shown at  62 . As a result, the lower end of the support member  10  wants to move to the right but the lower set of wings mobilises soil bulb  64  to resist movement about the pivot point. In contrast, applying a lateral load to the conventional beam  52  shown in  FIG. 11  results in insufficient lateral resistance from the weak or friable soil. As a result, the pivot point  66  is quite low down the beam. Due to the insufficient lateral resistance of the week or friable soil at the lower end of the beam  52 , the lower end of the beam  52  can also be moved to the right. As a result, the top of the beam  52  can bend or move in response to the applied lateral load. 
     As a further advantage, due to the stiffening effect of the wings  20 ,  22  and  30 ,  32  on the flange  18  of the beam  12 , the beam  12  can be made from a lighter gauge steel. 
     The size and strength of the beam and the size and positioning of the wings can be varied in accordance with design requirements and the geotechnical requirements of the particular site where the support members are to be driven into the ground. In some embodiments, the additional wings that extend transversely to the flanges may be included. However, in other embodiments, the beam web face area may be sufficient to support the specified loads, in which case the transverse wings can be omitted. 
     The support member  100  shown in  FIGS. 12 and 13  also includes a plurality of angled plates  80 ,  82 ,  84 ,  86  attached to the flanges  16 ,  18  of the beam  12 . As can best be seen with reference to plate  80  in  FIG. 12 , this forms a receptacle defined between the plate  80 , the web  14  and the flanges,  16 ,  18  of the beam  12 . The receptacle has a relatively large upper opening. The plate  80  has a lower edge that is spaced away from the web  14  so that a bottom opening in the form of a slot between the lower edge of the plate  80  and the web  14  is formed. In some embodiments, the lower edge of the plate  80  may come into contact with the web  14  (and be welded thereto), and the receptacle thus formed may have a lower opening formed by having a hole opening in the plate  80  at a lower region of the plate  80 . 
     The plates  80 ,  82 ,  84  and  86  may be described as cupping plates that form a cup having an upper opening and a lower opening for soil capture and drainage. The cups fill with soil or earth when the support member  100  is inserted into the ground. If any forces applied to the support member attempt to force the support member upwardly, the soil retained within the receptacles will resist that upward movement. In some ways, the plates act similarly to angled barbs on a spear, which resist extraction of the spear from flesh. 
     Although not shown in  FIGS. 12 and 13 , similar plates are located on the other side of the web  14 . These are essentially in their image orientation to the plates  80 ,  82 ,  84  and  86  shown in  FIGS. 12 and 13 . The plates also act to reinforce the lower part of the beam. 
     The plates may have bevelled leading bottom edges, for superior ground penetration during installation and correction of soil to optimise the end bearing pressure bulb sizes and shapes, around the support members, for improved compression and tension loading. 
     The plates may have bevelled leading bottom edges, for superior ground penetration during installation and direction of soil to optimise the end bearing pressure bulb sizes and shapes, around the support members, for improved compression and tension loading. 
     Sites that contain very weak soil/founding materials generally comprise the following 3 soil types: 
     Silty clay (firm/stiff and some sand),
 
Sandy silty clay mix (medium density to loose sand with some silty clay), all
 
Pure sand dune areas (loose to very loose sand).
 
     Each soil type provides a different source strength and soil action/reaction, which directly affects how the support members should be tuned for optimising performance and cost. In some instances, particularly in instances where the site contains loose to very loose sand, installation of the piles may involve installing the piles into the ground. The piles could then be watered with a very small amount of cement added to the water to create a very light “grey water” slurry. The low viscosity of the very light grey water slurry will ensure that the water penetrates down around the support members. The permeable nature of the very loose sand displaced during installation of the support members will settle with the water and then “set” down and around the support member. This is similar to a bucket of water being poured onto loose beach sand, but due to the concentration, depth and overburden pressure, it is far more effective. The sand will also filter the water, capturing the cement and bonding the sand granules together as it dries out. The end result will be a large sand/cement bulb bonded down and around the support member, for increased skin friction and therefore improved overall compression and tension load capability of the piles. 
     In simple terms, this added, simple, low-cost soil stabilisation/mediation process enables the weakest sand sites to be converted into superior soil strength sites. This particularly results in improved vertical skin friction loads for improved compression and tension load performance. 
     The support member may have a mounting arrangement or a connection plate attached to its upper end to enable a structure to be connected to the support member. The skilled person would readily understand how this can be achieved. 
     In the present specification and claims (if any), the word ‘comprising’ and its derivatives including ‘comprises’ and ‘comprise’ include each of the stated integers but does not exclude the inclusion of one or more further integers. 
     Reference throughout this specification to ‘one embodiment’ or ‘an embodiment’ means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearance of the phrases ‘in one embodiment’ or ‘in an embodiment’ in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more combinations. 
     In compliance with the statute, the invention has been described in language more or less specific to structural or methodical features. It is to be understood that the invention is not limited to specific features shown or described since the means herein described comprises preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims (if any) appropriately interpreted by those skilled in the art.