GB2552176A

GB2552176A - Ground pile

Info

Publication number: GB2552176A
Application number: GB1612091.7A
Authority: GB
Inventors: James Marshall Nicholas
Original assignee: Individual
Current assignee: Individual
Priority date: 2016-07-12
Filing date: 2016-07-12
Publication date: 2018-01-17
Also published as: GB201612091D0

Abstract

A ground pile suitable for forming a ground foundation 10 for supporting a structure 18. The ground pile features an elongate threaded pile member 12 which is screwed into the ground 20 and has a hollow interior section 26. It further features a structural load-bearing insert 14 which has an elongate main section 54 arranged to be inserted into and secured within the hollow interior section 26. There is also provided an insert coupling 56 at the upper end of the main section 54 to which a structure 18 can be coupled. Optionally, the threaded pile member 12 reduces in diameter along its length. Optionally, the elongate main section 54 of the insert 14 is coextensive with the hollow interior section 26 over the majority or substantially all the length of the hollow interior section 26.

Description

(71) Applicant(s):

Nicholas James Marshall

Flat 26, The Quays, Cumberland Road, Bristol,

BS1 6UQ, United Kingdom (72) Inventor(s):

Nicholas James Marshall (51) INT CL:

E02D5/56 (2006.01) E02D7/22 (2006.01)

E02D5/80 (2006.01)

(56) Documents Cited: GB 2456504 A	CN 203846490 U
CN 202989913 U	US 5482246 A
US 4467575 A	US 4405262 A
(58) Field of Search: INT CL E02D Other: EPODOC, WPI

(74) Agent and/or Address for Service:

Haseltine Lake LLP

Redcliff Quay, 120 Redd iff Street, BRISTOL, BS1 6HU, United Kingdom (54) Title of the Invention: Ground pile

Abstract Title: Screw pile with load bearing insert (57) A ground pile suitable for forming a ground foundation 10 for supporting a structure 18. The ground pile features an elongate threaded pile member 12 which is screwed into the ground 20 and has a hollow interior section 26. It further features a structural load-bearing insert 14 which has an elongate main section 54 arranged to be inserted into and secured within the hollow interior section 26. There is also provided an insert coupling 56 at the upper end of the main section 54 to which a structure 18 can be coupled. Optionally, the threaded pile member 12 reduces in diameter along its length. Optionally, the elongate main section 54 of the insert 14 is coextensive with the hollow interior section 26 over the majority or substantially all the length of the hollow interior section 26.

Fig. 1

GROUND PILE

The invention relates to a ground pile for forming a ground foundation for supporting a structure.

Ground foundations formed from hollow piles driven or screwed into the ground are commonly used for supporting ancillary structures such as platforms, signs/signals and mounts for equipment. They may also be used to increase ground stability as an alternative to “soil nails”.

Hollow piles may be driven or screwed into the ground and they generally provide improved performance (relative to cost, weight and versatility) compared with solid piles of similar length.

Methods of installation may vary depending on the size and weight of the piles, the accessibility of the site for mechanical plant equipment, the ground conditions and the scale of the project. Small piles may be installed in small quantities with hand tools, whereas large piles and/or quantities may require mobile plant equipment fitted with a rotating or an impact-driving attachment.

Recent and ongoing improvements in the capabilities and availability of hand-held and mobile plant equipment are leading to increased and more diverse uses for hollow screwpiles. However, the ability to use such screwpiles in appropriate dimensions and/or quantities may now be constrained by site-specific issues and manual handling regulations. In particular, small sites which are constrained to the use of small hollow piles may find that the available piles do not provide the required load-bearing capacity and/or service life. Although large and/or heavy piles can be segmented for assembly on site, this can lead to increased manufacturing and installation costs.

It is therefore desirable to provide an improved ground pile for forming a ground foundation.

According to an aspect there is provided a ground pile for forming a ground foundation for supporting a structure, comprising: an elongate threaded pile member arranged to be screwed into the ground and having a hollow interior section; and a structural load2 bearing insert having an elongate main section arranged to be inserted into and secured within the hollow interior section and an insert coupling provided at the upper end of the main section to which a structure can be coupled. The threaded pile member can be screwed into the ground with relative ease and can be a relatively thinwalled and lightweight component. The structural load-bearing insert can be easily inserted and secured within the hollow section of the threaded pile member, and may be designed for the appropriate loading conditions. The threaded pile member and the load-bearing insert may both be light enough such that they can be manually handled.

Further, the structural load-bearing insert may be less liable to damage during installation and consequently it may be designed with a reduced risk margin, thereby potentially reducing the cost and weight. Furthermore, locating the structural loadbearing insert within a hollow threaded pile member may protect the load-bearing insert and may reduce the likelihood of corrosion. In one arrangement, the load-bearing insert could be grouted within the hollow section and the grout could include an additive and/or act as a membrane to inhibit corrosion.

The threaded pile member may be threaded along one or more parts, or along substantially all of its length. The thread may be integrally formed, or it may be formed using one or more helix plates, for example. Further, the thread could be welded to one or more lengths of tube.

The insert coupling may comprise an insert coupling flange which may comprise a plurality of bolt holes. The insert coupling flange may lie in a plane perpendicular to the longitudinal axis of the load-bearing insert. This may enable the structure to be supported to be securely attached to the ground pile. The main section of the structural load-bearing insert may be solid. The main section of the structural loadbearing insert may have a substantially circular cross section. The main section of the structural load-bearing insert may be a single continuous section, or it may comprise a plurality of connected sections. In another arrangement the main section may comprise a plurality of elongate members. The plurality of elongate members may be arranged side-by-side and/or may be substantially parallel to one another. The plurality of elongate members may be substantially coextensive with one another. The structural load-bearing insert with a plurality of elongate members forming the main section may be referred to as a multi-core insert, and may comprise a rebar cage, for example.

The threaded pile member and the structural load-bearing insert may be configured such that the main section can be inserted into the hollow interior section such that it is coextensive with the hollow interior section over the majority or substantially all of the length of the hollow interior section. The length of the main section may be greater than the length of the hollow interior section. Alternatively, the length of the hollow interior section may be greater than the length of the main section.

The threaded pile member may have an open lower end or a closed lower end. The threaded pile member may reduce in diameter along its length and/or may be tapered along its length. The threaded pile member may have one or more tapered sections.

The upper end of the threaded pile member may be provided with a pile member coupling. The pile member coupling may be arranged to be coupled to the insert coupling. The pile member coupling may comprise a pile member coupling flange which may comprise a plurality of bolt holes. The pile member coupling flange may lie in a plane perpendicular to the longitudinal axis of the threaded pile member. The pile member coupling may provide an attachment feature for attaching or coupling an installation tool to the threaded pile member.

A side wall of the threaded pile member may comprise one or more openings (i.e. through-holes or apertures) which open into the hollow interior section. This may allow a binding and/or filling compound such as grout to penetrate into the surrounding soil matrix from the hollow interior section so as to increase ground stability.

The wall thickness, such as the nominal wall thickness, of the threaded pile member may be 10mm or less, 9mm or less, 8mm or less, 7mm or less, 6mm or less, 5mm or less, 4mm or less, or 3mm or less. The length of the threaded pile member may be 5m or less, 4.5m or less, 4m or less, 3.5m or less, or 3m or less. The maximum diameter, such as the maximum nominal diameter excluding the thread, of the elongate section of the threaded pile member may be 200mm or less, 180mm or less, 160mm or less, 140mm or less, 120mm or less, or 100mm or less. The mass of the threaded pile member may be 100kg or less, 90kg or less, 80kg or less, 70kg or less, 60kg or less,

50kg or less, or 25kg or less. These may be the practical limits for manual installation and the manual handling regulation limits for a handling team of up to four persons.

The length of the structural load-bearing insert may be 5m or less, 4.5m or less, 4m or less, 3.5m or less, or 3m or less. The length of the structural load-bearing insert may be 1m or more. The maximum diameter, such as the maximum nominal diameter, of the structural load-bearing insert may be 100mm or less, 80mm or less, 60mm or less, or 40mm or less. The minimum diameter, such as the minimum nominal diameter, of the structural load-bearing insert may be 10mm or more, or 20mm or more, or 30mm or more. The referred to diameters may be the diameters of the main section of the structural load-bearing insert. The mass of the structural load-bearing insert may be 100kg or less, 90kg or less, 80kg or less, 70kg or less, 60kg or less, 50kg or less, or 25kg or less.

According to another aspect there is provided a ground foundation formed using a ground pile in accordance with any statement herein, wherein the threaded pile member is screwed into the ground, and wherein the main section of the structural load-bearing insert is inserted into and secured within the hollow interior section. The main section may be grouted within the hollow interior section. This may secure the load-bearing insert within the hollow interior section of the threaded pile member and may also provide additional strength to the ground pile. The threaded pile member may project above ground level. The main section may be coextensive with the hollow interior section over the majority or substantially all of the length of the hollow interior section. The ground pile, for example the longitudinal axis of the ground pile, may be inclined from vertical. The ground pile may be inclined from vertical by 5 degrees or more, by 10 degrees or more, or by 15 degrees or more.

According to a further aspect there is provided an installation comprising at least one ground foundation in accordance with any statement herein, and a structure coupled to the insert coupling of the or each ground pile such that the structure is supported by the or each ground foundation. The structure may be a platform and/or a walkway and/or a building and/or a cabinet and/or an item or items of equipment. An interconnection, such as a ground beam or a mesh or grid, may be provided between a plurality of ground foundations and the structure.

According to yet a further aspect there is provided a method of forming a ground foundation using a ground pile in accordance with any statement herein, comprising: screwing the threaded pile member into the ground; and inserting the main section of the structural load-bearing insert into the hollow interior section of the threaded pile member and securing it therein. The threaded pile member may be screwed into the ground using hand-held equipment or mobile plant equipment.

The invention may comprise any combination of the features and/or limitations referred to herein, except combinations of such features as are mutually exclusive.

Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 schematically shows a ground foundation formed by a ground pile comprising a hollow screwpile and a structural load-bearing insert;

Figure 2 schematically shows the hollow screwpile of Figure 1;

Figure 3 schematically shows a side view of the structural load-bearing insert of Figure 1; and

Figures 4, 5 and 6 schematically show alternative ground foundations formed by a ground pile.

Figure 1 shows a ground foundation 10 installed on a slope such that the ground foundation 10 can support a structure. The ground foundation 10 is formed using a ground pile comprising a threaded pile member in the form of an elongate hollow screwpile 12 and a structural load-bearing insert 14. The screwpile 12 is screwed into the ground 20, and the structural load-bearing insert 14 is secured within the hollow screwpile 12 using grout. As will be described in detail below, the screwpile 12 can be screwed (or driven) into the ground with relative ease using hand-held equipment or small mobile plant equipment, and the structural load-bearing insert 14 is designed so as to support the load of the structure. The ground foundation 10 may be installed at any suitable location, and is particularly suitable for small-scale sites where access is limited, such as at the side of motorways or railways or the like. Further, the ground foundation 10 may support any suitable structure such as a platform, a walkway, a building, a cabinet or an item or items of equipment. An interconnection, such as a ground beam or a mesh or grid, may be provided between the plurality of ground foundations 10 and the structure.

Referring to Figure 2, the screwpile 12 is an elongate member having a longitudinal axis. The screwpile 12 comprises a longitudinally hollow interior section 26 that is coaxial with the screwpile 12 and which extends along the entire length of the screwpile 12 from an upper end to a lower end 22. In this embodiment, the screwpile 12 is formed from three hollow steel tube sections 28, 30, 32, each having a circular crosssection, which are welded together. The hollow steel tubes 28, 30, 32 reduce in diameter such that the screwpile 12 reduces in diameter from the upper end to the lower end 22. Of course, in other embodiments the screwpile 12 could be formed as a single piece or from any suitable number of sections or tubes assembled together.

In this embodiment the wall thickness of the hollow screwpile 12 is approximately 5mm and the length of the screwpile 12 is approximately 2.1m. The hollow interior 26 also has a length of approximately 2.1m. The maximum outer diameter of the screwpile (excluding the thread) is 114mm and the maximum inner diameter of hollow interior section 26 is 104mm. The minimum outer diameter of the screwpile is 60mm and the minimum inner diameter of hollow interior section 26 is 50mm. The mass of the hollow screwpile 12 is approximately 35kg. It should be appreciated that the screwpile 12 could have other suitable dimensions depending on the requirements. It may be desirable that the screwpile 12 is of a weight which allows it to be manually handled (i.e. carried) by two people, whilst complying with certain manual handling regulations.

The middle and lower sections 30 and 32 each comprise a threaded portion 42 extending partially along the length of the respective section. In another embodiment, the threaded sections 42 could extend along the whole length of the screwpile 12. The threaded sections 42 are welded to or integrally formed with the respective tube. However, in other embodiments the or each threaded section 42 could be formed by one or more helix plates welded to the or each tube. The thread 42 and the generally tapered shape of the screwpile 12 enables the screwpile 12 to be driven into the ground 20 relatively easily and accurately with hand-held equipment or small mobile plate equipment and with minimal ground disturbance.

The upper end of the screwpile 12 is provided with a pile coupling in the form of a flange 44 which lies in a plane substantially perpendicular to the longitudinal axis of the screwpile 12. The flange 44 comprises six circumferentially spaced bolt holes 46 that are evenly distributed. The lower end 22 of the screwpile 12 has an open end and the side wall has an axially extending slot 48 configured to receive a blade 50. The blade 50 is located within the slot 48 and is welded to the tube 32. The end 52 of the blade 50 is tapered to a point. This assists in the driving of the screwpile 12 into the ground 20. In other embodiments the blade 50 could be integrally formed, or there may be no blade. In some embodiments the lower end of the screwpile could be closed. In one embodiment, the screwpile 12 may be provided with one or more openings or apertures in a side wall of the screwpile 12. The openings/apertures may allow a binding and/or a filling compound such as grout to penetrate into the surrounding soil matrix from the hollow interior section 26 so as to improve stability.

Referring to Figure 3, the structural load-bearing insert 14 comprises an elongate main section 54 having a longitudinal axis and an insert coupling in the form of a flange 56 provided at the upper end of the insert 14. In this embodiment, the insert 14 is made from a metal such as stainless steel or galvanized carbon steel. However, it could be made from or comprise other metal and/or materials such as a polymer. The main section 54 has a circular cross-section of a constant diameter and is solid. However, it should be appreciated that the main section 54 may have any suitable cross-sectional shape. The flange 56 lies in a plane that is substantially perpendicular to the longitudinal axis of the insert. The flange 56 comprises six circumferentially spaced bolt holes 58 that are evenly distributed. The outer diameter of the flange 56 is substantially the same as that of the flange 44, and the bolt holes 46, 58 are in substantially the same locations.

In this embodiment, the length of the main section 54 of the insert 14 is 2m so that the main section 54 can be fully inserted into the hollow interior section 26 of the screwpile 12. The outer diameter of the main section 54 is approximately 38mm such that the main section 54 fits within the hollow interior section 26. The mass of the insert 14 is approximately 25kg. It should be appreciated that the insert 14 could have other suitable dimensions depending on the requirements. As for the screwpile 12, it may be desirable that the insert 14 is of weight which allows it to be manually handled (i.e.

carried) by two people, whilst complying with certain manual handling regulations. Importantly, the structural load-bearing insert 14, in particular the dimensions and material thereof, is designed based on the load capacity which the ground foundation must be capable of providing.

Referring back to Figure 1, in order to form a ground foundation 10, the screwpile 12 is driven by rotation into the ground 20 by means of hand-held or small mobile plant equipment having a rotational driving head. The screwpile 12 is screwed into the ground 20 such that the flange 44 is at the desired height from the surface of the ground 20. The main section 54 of the insert 14 is then inserted into the hollow interior section 26 such that the flange 56 sits at the desired height. A small amount of aggregate or grout may be introduced into the hollow interior section 26 before and/or after the insert 14 is inserted. In the embodiment shown in Figure 1, the flange 56 of the insert 14 is slightly spaced from the flange 44 and the main section 54 is coextensive with the hollow interior section 26 over substantially all of the length of the hollow interior section 26. The insert 14 is secured within the screwpile 12 using grout 60. In other embodiments, the insert 14 may be secured within the hollow interior section 26 using other means. Once the grout 60 has set, the ground foundation 10 can be used to support a structure 18, such as a platform. In the embodiment shown in Figure 1, the structure 18 is bolted to the flange 56 of the insert 14 to support the structure 18. However, in other embodiments the structure 18 could be clamped to the flange 56. Although it has been described that the screwpile 12 and insert 14 comprise a flange 44, 56 any suitable coupling could be used. Further, although only a single ground foundation 10 is shown in Figure 1, it should be appreciated that multiple ground foundations 10 may be used together to support a single structure 18.

Figure 4 shows an alternative installation in which the structural load-bearing insert 14 is inserted into the hollow interior section 26 of the screwpile 12 such that the flanges 44, 56 abut one another. The structure 18 is then bolted to both flanges 44, 56 by passing bolts through the bolt holes 46, 58 in the two flanges. This may more reliably secure the structure 18 to the ground foundation.

Figure 5 shows an alternative installation which is somewhat similar to the embodiment of Figure 4. However, the structure 18 to be supported is mounted on a sub-frame comprising an I-beam 64. In this embodiment the I-beam 64 is made from a polymer so as to reduce the weight and for ease of manual handling. However, other materials could be used for the I-beam. The I-beam 64 is secured to the ground foundation 10 using a clamp assembly comprising clamp plate 66 at a set of ancillary components 62 (spacers, bolts, nuts etc.). The clamp assembly fits around the flanges 44, 56 of the screwpile 12 and the insert 14 and clamps the I-beam 64 to the clamp plate 66 and the flanges 44, 56. In the embodiment shown in Figure 5 the sub-frame comprise an I-beam 64. However, in other embodiments the sub-frame could comprise any number of suitable components such as a rod, a bar, a plate, an angle-section, a T-section, a channel, a hollow box-section and/or a hollow tube.

Figure 6 shows another alternative installation in which the ground foundation 10 is inclined (from vertical) for improved ground penetration and/or stability. An asymmetrical joint member 68 is installed between the insert coupling 56 and the Ibeam 64 to achieve the required alignment (e.g. horizontal alignment) of the structure

18. The joint member 68 comprises a first flange and a second flange which lie in nonparallel planes. The angle between the planes within which the first and second flanges lie corresponds to the angle between the longitudinal axis of the structural loadbearing insert 14 and vertical. In other embodiments the asymmetrical joint member 68 may be integral with the insert coupling 56 and/or the I-beam 64 and/or the structure 18 and/or one or more clamp plates 66. In other embodiments the asymmetrical joint member 68 may be adjustable and/or may be installed with ancillary components such as shims to achieve the required alignment of the structure 18. In other embodiments the insert coupling 56 and/or the I-beam 64 and/or the structure 18 may be bolted to the asymmetrical joint member 68 broadly as shown in Figure 4.

The inclined configuration shown in Figure 6 illustrates a further benefit wherein a conventional “off-the-shelf” screwpile 12 is used in conjunction with a structural loadbearing insert 14 and ancillary components and wherein the structural load-bearing insert 14 and ancillary components can be designed and manufactured to meet a complex and precise set of requirements such as orientation, offset, load capacity, deflection limits and service life.

The ground pile comprising a hollow screwpile 12 and a structural load-bearing insert 14 provides a number of advantages over existing arrangements. The screwpile 12 is of such dimensions that it can be manually handled and can be easily rotatably driven into the ground using hand-held or small mobile equipment. This allows it to be installed on sites having restricted access. The screwpile 12 is not required for its structural load-bearing capabilities perse, and instead is primarily used to bore into the ground, engage with the surrounding soil, and provide a cavity (the hollow interior 26) for the structural load-bearing insert 14. This allows conventional “off-the-shelf” screwpiles 12 to be used and renders it unnecessary to calculate their load-bearing capabilities. The structural load-bearing insert 14 is also of such dimensions that it can be manually handled, which again means that the ground pile can be installed in sites having limited access. Unlike the screwpile 12, the structural load-bearing insert 14 is specifically designed for its load bearing capabilities and/or service life and may be rated for particular requirements. In some arrangements, the installer may be able to choose from one of a series of load-bearing inserts 14, each rated for a particular load and/or service life. The grout 60, or other fixing means, ensures that the load is effectively transferred from the structural load-bearing insert 14 to the screwpile 12, which transfers the load into the surrounding soil matrix. The ground pile as described herein is therefore a particularly cost-effective and efficient way of creating a ground foundation, particularly for situations where site access is limited.

Claims

CLAIMS:

1. A ground pile for forming a ground foundation for supporting a structure, comprising:

an elongate threaded pile member arranged to be screwed into the ground and having a hollow interior section; and a structural load-bearing insert having an elongate main section arranged to be inserted into and secured within the hollow interior section and an insert coupling provided at the upper end of the main section to which a structure can be coupled.

2. A ground pile according to claim 1, wherein the insert coupling comprises an insert coupling flange.

3. A ground pile according to claim 2, wherein the insert coupling flange comprises a plurality of bolt holes.

4. A ground pile according to any preceding claim, wherein the main section is solid.

5. A ground pile according to any preceding claim, wherein the threaded pile member and the structural load-bearing insert are configured such that the main section can be inserted into the hollow interior section such that it is coextensive with the hollow interior section over the majority or substantially all of the length of the hollow interior section.

6. A ground pile according to any preceding claim, wherein the threaded pile member reduces in diameter along its length.

7. A ground pile according to any preceding claim, wherein the upper end of the threaded pile member is provided with a pile member coupling.

8. A ground pile according to claim 7, wherein the pile member coupling is arranged to be coupled to the insert coupling.

9. A ground pile according to claim 7 or 8, wherein the pile member coupling comprises a pile member coupling flange.

10. A ground pile according to claim 9, wherein the pile member coupling flange comprises a plurality of bolt holes.

11. A ground pile according to any preceding claim, wherein a side wall of the threaded pile member comprises one or more openings which open into the hollow interior section.

12. A ground pile according to any preceding claim, wherein the wall thickness of the threaded pile member is 7mm or less.

13. A ground pile according to any preceding claim, wherein the length of the threaded pile member is 3.6m or less.

14. A ground pile according to any preceding claim, wherein the maximum diameter of the threaded pile member is 160mm or less.

15. A ground pile according to any preceding claim, wherein the mass of the threaded pile member is 80kg or less.

16. A ground pile according to any preceding claim, wherein the length of the structural load-bearing insert is 3.5m or less.

17. A ground pile according to any preceding claim, wherein the maximum diameter of the structural load-bearing insert is 60mm or less.

18. A ground pile according to any preceding claim, wherein the mass of the structural load-bearing insert is 80kg or less.

19. A structural load-bearing insert for use with the ground pile in accordance with any preceding claim.

20. A ground foundation formed using the ground pile in accordance with any of claims 1-18, wherein the threaded pile member is screwed into the ground, and wherein the main section of the structural load-bearing insert is inserted into and secured within the hollow interior section.

21. A ground foundation according to claim 20, wherein the main section is grouted within the hollow interior section.

22. A ground foundation according to claim 20 or 21, wherein the threaded pile member projects above ground level.

23. A ground foundation according to any of claims 20-22, wherein the main section is coextensive with the hollow interior section over the majority or substantially all of the length of the hollow interior section.

24. A ground foundation according to any of claims 20-23, wherein the ground pile is inclined from vertical.

25. An installation comprising at least one ground foundation in accordance with any of claims 20-24, and a structure coupled to the insert coupling of the or each ground pile such that the structure is supported by the or each ground foundation.

26. An installation according to claim 25, wherein the structure is a platform and/or a walkway and/or a building and/or a cabinet and/or an item or items of equipment and/or a mount for equipment.

27. A ground pile, ground foundation or installation substantially as described herein with reference to the accompanying drawings.

28. A method of forming a ground foundation using a ground pile in accordance with any of claims 1-18, comprising:

screwing the threaded pile member into the ground; and inserting the main section of the structural load-bearing insert into the hollow interior section of the threaded pile member and securing it therein.

29. A method according to claim 28, wherein the threaded pile member is screwed into the ground using hand-held equipment or mobile plant equipment.

30. A method according to claim 28 and substantially as described herein.

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