GB2548404A

GB2548404A - Pile cap

Info

Publication number: GB2548404A
Application number: GB1604629.4A
Authority: GB
Inventors: Howard Andrew
Original assignee: Individual
Current assignee: Individual
Priority date: 2016-03-18
Filing date: 2016-03-18
Publication date: 2017-09-20
Anticipated expiration: 2036-03-18
Also published as: GB2548404B; GB201604629D0

Abstract

A pile cap 10 comprises a support surface 11 for covering a mouth of a bore through a pile 1 and at least one engagement member 20 to engage with a side of the pile. The cap comprises at least one void 12 arranged to allow access to fastening elements 3 provided around the mouth of the pile. The pile cap caps the top of the installed pile before equipment is installed on the pile. The voids enable equipment to be attached to the pile with the pile cap in-situ. Each void may be a cut-out and may be semi-circular. The at least one engagement member may be an outer engagement member at the periphery of the support surface, or an inner engagement member provided inwardly of the periphery of the support surface, or a combination of both. The cap may have a plurality of strengthening ribs which may be circular and/or radial. The cap may have a threaded bore 13 to receive a threaded surveying pin. The cap may be made of plastic or metal and may be a distinctive colour.

Description

Pile Cap

Technical Field of the Invention

The present invention relates to a pile cap, that is to say, a cap arranged to be placed on a sunk pile. The invention is particularly concerned with caps for tubular piles and especially Circular Hollow Section (CHS) piles, especially, but not exclusively those of around 50-100cms in diameter.

Background to the Invention

Piles, such as CHS piles, are regularly used in construction, for example in rail infrastructure. For example, in order to install gantries and so forth, a series of 610mm CHS piles are installed in the ground alongside the track, and masts, gantries etc are subsequently attached to the top of the piles. Figure 1 shows the top of a 610mm CHS pile 1 with equipment in the form of a gantry 2 attached thereto. Obviously other sizes of pile can also be used to the same end, for example 762mm CHS piles are relatively common.

To this end, piles, such as CHS piles 1 are typically provided with a series of fastening elements 3, such as vertical apertures/bores, around the edge of the pile. These fastening elements 3, typically around 6 in number, are arranged to align with similar fastening elements 4 such as vertical apertures^ores in the equipment 2 to be attached to the pile 1, whereby fasteners such as bolts 5 can fasten the equipment 2 to the pile 1, via the fastening elements 3,4, e.g.by screwing into corresponding nuts 6.

In major civil engineering projects, such as installation of gantries for electrification of railways, for example, piles will frequently be installed as a first stage, with the equipment such as masts/gantries attached to the pile many weeks or months later. Consequently, many weeks or months may pass during which a 600mm hole (the internal diameter of the pile 1) sits, open on the site. This is a safety hazard, both for site-workers, and for wildlife, such as badgers, foxes, dormice, bats or newts, as well as various species of birds, all of which could fall into the pile.

To minimise the potential hazard to workers, it is known to place sheets of plywood over the top of the open pile, and weigh them down in position using bricks/stones, or to attempt to fix them in position using cable ties. Such sheets of plywood are normally square and have no fixing points. Consequently they may fall off, be knocked off, or even degrade over time to the extent that they are no longer capable of supporting a falling worker. Also, they often do not cover the entire surface of the pile, allowing wildlife to fall through the gaps.

When it comes to installing equipment on the piles 1, the sheets of plywood are removed (to allow access to the fastening elements), a wooden template is attached to the pile and an aligning tool is attached to the template to check alignment before installation of the equipment. The templates are slow to line up and not always accurate. The sheets of plywood and any plastic ties are generally discarded at this stage.

Once alignment has been checked, the equipment 2 is attached to the pile 1 (e.g. bolted through the fastening elements), generally leaving a vertical gap 7 of say 4-6 inches around the circumference of the pile, which whilst no longer a danger to workers on the site, still leaves a gap through which small animals can fall into the pile 1.

Summary of the Invention

According to a first aspect of the invention, there is provided a pile cap comprising a support surface for covering a the mouth of a bore through a pile and at least one engagement member to engage with a side of the pile, wherein the cap comprises at least one void arranged to allow access to fastening elements provided around the mouth of the pile.

Providing a dedicated pile cap, with engagement members to engage with the side of the pile makes installing the cap faster and easier than trying to attach sheets of plywood. Since the cap is provided with engagement members a more solid connection can also be obtained. Moreover, the provision of one or more void to allow access to fastening elements around the mouth of the pile, means that unlike sheets of plywood which must be removed before attaching equipment to the pile, the pile cap can remain in-situ when equipment is attached to the pile, both reducing time, because the removal step is omitted and providing a positive environmental impact, since the cap continues to prevent certain small animals falling into the pile even after the equipment is installed. A plurality of voids may be provided. The plurality may be at least 2,3,4,5 or (most preferably) 6. CHS piles typically have 6 fastening elements, and whilst a single void could allow access to more than one fastening element, providing individual voids for each fastening element can improve strength and reduce the gap between the void and the support surface.

The or each void may be a cut-out or an aperture.

The support surface may be substantially circular. For example, the support surface may be circular except for cut-outs at the peripheral edge of the circular surface.

The voids may be substantially semi-circular. For example, the voids may extend in a circular arc from the peripheral edge of the support surface, but need not define the whole 180 degrees of a semi-circle. Less than 180 degrees allows a greater space in which a spanner can be used to tighten a nut/bolt

The voids may be grouped. In particular a first group of (e.g. three) evenly spaced voids may be provided on one side of the pile cap and a second group of (e.g. three) evenly spaced voids may be provided on the other side of the pile cap, wherein each void in each group is closer to at least one void in its group than to any voids in another group.

The groups of voids may be arranged symmetrically about a line of symmetry extending across the support surface.

At least one engagement member may be an outer engagement member, provided at the periphery of the support surface, depending therefrom. With this arrangement, the engagement member engages the outer side of the pile.

At least one engagement member may be an inner engagement member, provided inward of the periphery of the support surface, depending therefrom. With this arrangement, the engagement member engages the inside of the pile (i.e. the bore), to hold the pile cap in place. The region of the support surface outside the inner engagement member, on the other hand, prevents the cap itself from falling down the pile. A plurality of inner and/or outer engagement members may be provided. For example, at least 2,3,4,5 or (most preferably) 6 inner engagement members, and/or at least 2,3,4,5 or (most preferably) 6 outer engagement members.

The or each engagement member may be arcuate (so as to match the arc of the pile).

The pile cap may comprise one or more strengthening ribs, for example one, two or more circular ribs, which may be concentric with the centre of the pile cap and/or a series of radial ribs (e.g. 1,2,3,4,5,6,7,8 or more ribs) extending from the centre (or near thereto) to (or near to) the periphery.

The pile cap may comprise a threaded bore to receive a threaded surveying pin.

The threaded bore may be provided at the centre of the support surface and may extend perpendicularly to the plane of the support surface.

The support surface may be provided with apertures, such as slits or slots to reduce weight. The slits or slots may be less than 5cm wide, preferably less than 3cm wide. Provision of slots/slits is useful in weight saving. However, to effectively prevent certain important species of animals from falling down the pile, these relatively small widths are provided.

The support surface may be capable of supporting the weight of a person, e.g. it may be capable of resisting a force of lOOON over an area of lOOcm^, preferably at least 2000N over an area of lOOcm^ to account for acceleration in falling and the potential for the force to be directed over a small surface area, e.g. an elbow, knee, foot or hand. The support surface may carry a SWL of at least lOOkN, more preferably at least 200kN.

The pile cap is preferably formed of plastic, or alternatively of metal, both of which biodegrade slowly.

The pile cap may have a diameter of at least 50cm, for example 50-100cm, e g. about 610mm to match 610mm diameter piles, or 762mm to match 762mm piles.

The pile cap may be formed from a material with a distinctive colour, or have a distinctively coloured coating. A distinctive colour, such as a bright or fluorescent colour (e.g. fluorescent orange) will help highlight the presence of a pile, and reduce the prospect of workers tripping over the pile. Whilst having the cap in place prevents workers from actually falling into the pile causing major injury, the top of a pile sticking out of the ground at a relatively low level remains a trip-hazard; the distinctive colour makes this more visible and less likely to cause minor injury.

According to a second aspect of the invention, there is provided a method of securing a pile comprising placing a pile cap according to the first aspect of the invention over the mouth of the bore of the pile, such that the support surface covers the mouth of the bore and one of more engagement members engage with the inside or outside of the pile.

The method may comprise first installing the pile in the ground. The method may comprise subsequently attaching equipment to the pile, via fastening elements, with the pile cap in situ.

The method may comprise checking alignment by attaching a threaded surveying pin to the pile cap in-situ, via a threaded bore provided in the pile cap and aligned with the central axis of the pile prior to attaching equipment to the pile.

Detailed Description of the Invention

In order that the invention may be more clearly understood an embodiment thereof will now be described, by way of example only, with reference to the accompanying drawings, of which:

Figure 1 shows a perspective view of equipment attached to a CHS pile according to the prior art;

Figure 2 shows a perspective view of a pile cap according to the invention installed on a pile;

Figure 3 shows a perspective view of the pile cap of figure 2;

Figure 4 shows a plan view of the pile cap of figures 2 and 3;

Figure 5 shows a lateral cross sectional view through the pile cap of figures 2 to 4; and

Figure 6 shows an underneath view of the pile cap of figures 2 to 5.

With reference to figure 2, a pile cap 10 is fitted to the top of an installed pile 1, so as to cover the bore of the pile 1, but not cover, and thereby to leave free access to, the fastening elements 3, through which in use, fasteners (not shown) such as bolts or the like may be used to connect equipment (not shown) such as masts, gantries and the like to the pile 1.

Referring to figures 3-6, the pile cap 10 is a substantially circular device, made up primarily of a disc shaped body 11 sized to have the same diameter as the outer diameter of the pile which it is intended to cap and forming a support surface. Consequently, in this specific embodiment for use with a 610mm pile, the diameter of the disc shaped body is 610mm. Those skilled in the art will readily appreciate that other sizes could be used.

At the periphery, or circumference, of the disc, a plurality of voids 12 are formed. In this embodiment, six voids 12 are formed, each taking the form of a segment of a circle cut-out from the periphery of the disc 11. Each cut-out is an almost complete semicircle (about 150 degrees of a circle), with a centre of symmetry about a diameter/radius of the disc. Obviously other shapes could be used and the centre of symmetry is not essential.

The pile cap 10 of this embodiment is intended to match a 610mm CHS pile formed with six fastening elements 3. The voids 12 are consequently arranged in two groups, each group of three voids 12 having a central void 12a and two flanking voids 12b either side, each having a centre 45 degrees from the centre of the central void. The two groups of voids 12 are diametrically opposed and symmetrical. Consequently, the centre of nearest neighbouring voids 12 between one group and the other is 90 degrees.

This arrangement is provided because it is the same as the arrangement of fastening elements on the 610 CHS pile. Accordingly, when placed on top of the pile 1, the voids 12 line up with the fastening elements 3. Those skilled in the art will appreciate that alternative arrangements of voids 12 could be used to match other piles. Indeed additional voids 12 would not unduly hinder the operation of the pile cap 10, although they could create extra gaps and reduce the strength of the device.

In this specific embodiment, for this specific pile 1 the substantially semi-circular voids 12 have a radius of 47.5mm. It will immediately be appreciated that just as the shape can be different, so can the radius, but for this particular embodiment, that radius is suitable to leave sufficient space around the fastening elements to fit fasteners and allow a spanner or the like to turn the fasteners, whilst leaving only a small gap between the pile cap 10 and the pile 1, to reduce the number of species that can fall through the gap.

At the exact centre of the disc shaped body 11, a threaded bore 13 is formed. The bore 13 is formed with an M8 thread capable of withstanding hand-insertion of a correspondingly threaded surveying pin, used for alignment. In order to support the pin and keep it perpendicular to the plane of the disc shaped body 11, the central region 14 of the disc shaped body 11 is formed thicker/deeper than the remainder of the disc 11. Suitably, this region is between 1cm and 3cm deep and in this embodiment it is 15mm deep. By contrast, the remainder of the disc is around 2-5mm thick, e.g. 4mm thick.

In order to reduce weight, and assist in drainage, the disc 11 is slotted. In this embodiment, arcuate slots 15 are provided in five concentric rings around the disc 11, each of the four innermost rings comprising 8 slots, whilst the outer ring comprises 14 slots (because two slots are provided alongside each void 12, rather than a single slot).

Eight radially extending ribs 16 extend from a circular rib 17 near the centre of the pile cap 10 to the periphery (as best seen in figure 6). These radially extending ribs 16 divide the disc 11 into 8 segments, with the slots 15 (and the voids 12) formed between the radially extending ribs 16. A second circular rib 18 is provided approximately midway between the centre of the disc 11 and its periphery. Each of these ribs is in the region of 30-40mm deep (i.e. they extend about 30-40 mm from the underside of the disc 11).

The radially extending ribs 16 are rebated, such that their outermost region, in the 19mm where they extend to the outermost periphery of the disc 11, they are slightly lower, having a depth of around 20mm. Correspondingly, a sidewall 19 of around 20mm in depth is provided at the periphery of the disc between the voids 12. This sidewall continues at around 20mm in depth along the edge of the voids 12, but only in the region up to 19mm inward from the outermost periphery of the disc 11. 19mm inward from the outermost periphery of the di sc 11, engagement members 20 are formed. These engagement members 20 are formed as arcuate skirts running parallel with the outermost periphery of the disc 11 between the voids 12.

The skirts 20 are deeper than the rebated region of the radially extending ribs 16, and the sidewall 19. A suitable depth is at least 10mm to 30mm greater than the depth of the rebated region, or more and in this embodiment the depth of the skirts 20 is 45mm, i.e. 25mm more than the rebated region. Webs 21 extend between the skirts 20, following the contour of the voids 12, so as to connect the skirts 20 and resist excessive inward bending, whilst allowing a degree of resilience.

The distance of 19mm from the outermost periphery of the disc 11 is deliberately chosen to match the diameter of the bore of a 610 CHS pile, such that the engagement members 20 form a resistance fit in the bore. It will therefore be readily appreciated that this distance is dependent on the diameter of the bore of the pile to be capped, rather than any arbitrary distance from the outer periphery.

Indeed, whilst this embodiment has an outer periphery of the disc 11 that matches that of the pile 1, the periphery of the disc 11 could extend beyond that of the pile - in this case, the key dimension for the engagement member 20 would remain that of the bore, not an arbitrary distance from the outer periphery of the disc 11.

It is preferred that the pile cap 10 does not extend beyond the diameter of the pile 1, to reduce the chances of it being knocked off However, it is quite conceivable that the engagement members 20 could instead be provided at the outermost periphery to engage with the outer surface of the pile 1, rather than (or as well as) the bore. A pile cap 10 according to the invention could be formed for example from sheet metal, e.g. aluminium or steel, but this embodiment is formed by injection moulding plastics, e.g. HDPE to the general shape, trimming as necessary, then boring and threading the central bore 13. HDPE is durable and very slow to biodegrade.

The HDPE includes a bright dye, e.g. fluorescent orange, in order that the pile cap 10 has a distinctive colour, noticeably contrasting to other colours likely to be seen on the ground (e.g. natural greens, browns and greys). Alternatively a coating, e.g. painting, step could take place to provide the bright colour after formation.

With reference to figure 2, in use, a pile 1 is installed in the ground by known piling methods, e.g. pile driving. Subsequently, the pile cap 10 is arranged such that the voids 13 line up with the fastening elements 3 and pushed into the pile 1, such that the engagement members 20 engage with the inside of the bore of the pile 1, forming a resistance fit therewith, so as to firmly hold the pile cap 10 in place, covering the mouth of the bore.

The pile cap 10 may then remain in place as further infrastructure is build, during which time the top of the pile is both brightly coloured so it is likely to be noticed, and firmly covered, so in the event that a person trips onto the support surface, that person will not fall down the pile 1. The pile cap 10 of the invention has been tested and carries a SWL (safe working load) of 238kN; more than enough to prevent a large man from breaking it with his fall.

After some time, prior to installing equipment (not shown) on the pile 1, alignment can be checked by screwing a threaded surveying pin (not shown) into the bore 13 of the pile cap 10 and connecting aligning tool thereto.

Subsequently, and whilst the pile cap 10 remains in-situ, equipment (not shown) such as a mast or gantry is connected to the pile 1 in the known manner, using fasteners such as nuts and bolts. The pile cap 10 remains in-situ even with the equipment attached and thereby continues to prevent small animals from falling down the pile (provided that the small animals cannot fit through the slots 15.

The above embodiment is described by way of example only. Many variations are possible without departing from the scope of the invention as defined in the appended claims.

Claims

1. A pile cap comprising a support surface for covering a the mouth of a bore through a pile and at least one engagement member to engage with a side of the pile, wherein the cap comprises at least one void arranged to allow access to fastening elements provided around the mouth of the pile.

2. A pile cap according to claim 1 comprising a plurality of voids

3. A pile cap according to claim 2 wherein the plurality of voids is six voids.

4. A pile cap according to any of the preceding claims wherein the or each void is a cut-out.

5. A pile cap according to any preceding claim wherein the support surface is substantially circular.

6. A pile cap according to claim 5 wherein the support surface is circular except for cut-outs at the peripheral edge of the circular surface.

7. A pile cap according to any preceding claim wherein the or each void is substantially semi-circular.

8. A pile cap according to any of claims 1-6 wherein the or each void extends in a circular arc from the peripheral edge of the support surface, and defines less than 180 degrees of a semi-circle.

9. A pile cap according to any of claims 2-8 comprising groups of voids.

10. A pile cap according to claim 9 wherein a first group of three evenly spaced voids is provided on one side of the pile cap and a second group of three evenly spaced voids is provided on the other side of the pile cap, wherein each void in each group is closer to at least one void in its group than to any voids in another group.

11. A pile cap according to claim 9 or 10 wherein the groups of voids are arranged symmetrically about a line of symmetry extending across the support surface.

12. A pile cap according to any preceding claim wherein at least one engagement member is an outer engagement member, provided at the periphery of the support surface, depending therefrom.

13. A pile cap according to any preceding claim wherein at least one engagement member is an inner engagement member, provided inward of the periphery of the support surface, depending therefrom.

14. A pile cap according to claim 12 or 13 wherein a plurality of inner and/or outer engagement members are provided.

15. A pile cap according to claim 14 wherein at least 6 inner engagement members, and/or at least 6 outer engagement members are provided.

16. A pile cap according to any preceding claim wherein the or each engagement member is arcuate.

17. A pile cap according to any preceding claims comprising one or more strengthening ribs.

18. A pile cap according to claim 17 comprising one, two or more circular ribs, which are concentric with the centre of the pile cap and/or a series of radial ribs extending from the centre or near thereto to or near to the periphery.

19. A pile cap according to any preceding claim comprising a threaded bore to receive a threaded surveying pin.

20. A pile cap according to claim 19 wherein the threaded bore is provided at the centre of the support surface and extends perpendicularly to the plane of the support surface.

21. A pile cap according to any preceding claim wherein the support surface is provided with apertures therein.

22. A pile cap according to any preceding claim wherein the support surface is capable of supporting the weight of a person

23. A pile cap according to any preceding claim wherein the support surface is capable of resisting a force of 2000N over an area of lOOcm^

24. A pile cap according to any preceding claim wherein the support surface is capable of carrying a SWL of at least lOOkN.

25. A pile cap according to any preceding claim which is formed of plastic, or metal

26. A pile cap according to any preceding claim having a diameter of 50-100cm.

27. A pile cap according to any preceding claim which is formed from a material with a distinctive colour, or has a distinctively coloured coating.

28. A method of securing a pile comprising placing a pile cap according to any of claims 1-27 over the mouth of the bore of the pile, such that the support surface covers the mouth of the bore and one of more engagement members engage with the inside or outside of the pile.

29. A method according to claim 28 comprising first installing the pile in the ground.

30. A method according to claim 28 or claim 29 comprising subsequently attaching equipment to the pile, via fastening elements, with the pile cap in situ.

31. A method according to any of claims 28-30 comprising checking alignment by attaching a threaded surveying pin to the pile cap in-situ, via a threaded bore provided in the pile cap and aligned with the central axis of the pile prior to attaching equipment to the pile.

32. A pile cap, a method of forming a pile cap or a method of securing a pile substantially as described herein with reference to the accompanying drawings.