GB2479134A

GB2479134A - Winged pile sleeve

Info

Publication number: GB2479134A
Application number: GB1005250A
Authority: GB
Inventors: Barry William Peter Stokes
Original assignee: Screwfast Foundations Ltd
Current assignee: Screwfast Foundations Ltd
Priority date: 2010-03-29
Filing date: 2010-03-29
Publication date: 2011-10-05
Also published as: GB201005250D0; GB201005971D0

Abstract

A pile sleeve assembled from 4 pieces 11/12/13/14 each comprising a substantially planar panel 15 with a perpendicular flange 16 along one edge. The flange 16 of one wing is secured to the adjacent wing spaced away from the adjacent piece's flange forming a passage 20 for a pile 30. When the sleeve is fitted over a pile section fins project outwards from the sleeve. The leading edge of each wing may be tapered. The 4 pieces which form the sleeve may be connected together in a symmetrical arrangement.

Description

A WINGED PILE SLEEVE

The present invention relates to a winged pile sleeve Tubular steel piles, which are either percussively driven into the ground or have a helical fin and are installed by rotary action, are relatively slender compared to piles made of concrete and other materials because they have a high strength to weight ratio. The most frequent use of tubular steel piles is to transmit compression loads from superstructures down to competent soils at depth in the ground. When they are required to transmit loads from lightweight structures that are subject to relatively large horizontal loads, as may be generated by wind forces, their slenderness provides only a relatively small area to resist such horizontal loads. This problem can be overcome by using larger diameter piles or by installing the piles at an angle so that they "lean" against the horizontal forces. The former measure is wasteful of material and the latter is difficult to accomplish with efficiency.

In order to increase the lateral area of tubular steel piles, various winged pile sleeves have been devised, as disclosed, for example, in US 3,011,597, US 4,833,846 and the applicant's own GB2420581. These known winged pile sleeves comprise a tubular body provided with a plurality of longitudinally extending, radially projecting fins (also referred to as wings) which taper in the direction of the leading end of the body, such sleeves being intended for location around a trailing end of the primary pile after the latter has been driven into the ground. While such pile sleeves are now in general use, the cost of their production, storage and transport is a considerable factor. The present invention seeks to reduce those costs by means of a new approach to the problem.

Pre-fabricated winged sleeves, as disclosed in GB 2420581 and in current use, do not stack in an efficient manner for storage and transportation purposes and their weight and bulk makes their manual handling difficult for transport and on-site manipulation.

The present invention proposes that a winged pile is assembled from four pieces each comprising a substantially planar panel having a substantially perpendicular flange along one side edge, the panels being connected together so that the flange of each piece is secured to a longitudinal region of the panel of the adjacent piece, spaced apart from the flange of the adjacent piece, so as to define a passage of substantially rectangular cross-section through the centre of the assembled sleeve whereby the sleeve is fitted over the pile section and at least some of the panels extend beyond said connection to provide wings projecting outwards from the pile sleeve.

In preferred embodiments all four pieces are substantially identical in shape and size, or opposing pairs of pieces are substantially identical to each other, but different to the other opposing pair so that the pieces are connected together in a symmetrical arrangement.

In embodiments where the pieces are identical, and in other embodiments where four wings are required, the flange of each piece is connected generally midway between the flange and an opposing edge of the adjacent piece and each of the panels extends outwards beyond the connection to provide the wings of the pile sleeve.

A set of prefabricated pieces, namely the four panel pieces with upstand edge margins, are provided that can be bolted together on site to form a winged pile sleeve. However, when circumstances dictate, they may additionally or alternatively be connected together by welding or they may be connected by bolting together before being brought on to a site of use.

The size and shape of the pieces is designed to improve the portability of the winged sleeve and has a number of associated efficiency and cost advantages, as well as greater feasibility in terms of transportation to site.

The invention will be described further by way of example, by reference to the accompanying drawings, in which: Figure 1 is a perspective view of a practical embodiment of the assembled winged pile sleeve according to the invention shown schematically and as fitted over a section of a tubular pile; Figure 2 is a side view, to an enlarged scale, of the pile sleeve shown in figure 1; Figure 3 is a plan view of the pile sleeve shown in figures 1 and 2; Figure 4 shows, to a reduced scale, a single sheet of steel marked out with a pattern for cutting, drilling and folding to provide all the pieces required for an assembled winged sleeve as shown in the previous figures; and Figure 5 is a plan view, comparable to figure 3, of a modified version of pile sleeve in accordance with the invention.

As shown in figures 1 to 4, a typical practical embodiment of winged pile sleeve in accordance with the invention is assembled from four substantially identical pieces 11 to 14 of sheet steel which can economically be cut from a single sheet of steel according to the plan shown in Figure 4. Each piece consists of a major portion in the form of a planar panel 15 which provides a respective wing of the assembled sleeve and a substantially perpendicular flange 16 along one side edge of the panel 15 for purposes of attachment to a longitudinal central region of the panel 15 of the adjacent piece, as apparent in figure 1.

When the pieces 11 to 14 are connected in this way, in a symmetrical array, a central passageway 20 of substantially rectangular cross-section is defined. In use, this passageway 20 locates over a pile section 30, as shown in figure 1, typically being installed, if necessary driven in, below ground surface over the trailing end of the pile 30 after the latter has been installed. The four wings which extend outwards significantly increase the lateral area presented to surrounding ground and consequently increase the ability of the pile of 30 to offer resistance to lateral loading.

A corner of each panel 15 is cut obliquely at 25 to provide a taper at the lower end of each wing.

During fabrication each panel 15 and its flange 16 may be cut as a single flat piece from the sheet steel blank shown in figure 4 and the respective edge margins then bent along fold lines 19, shown in figure 4, to provide the perpendicular flanges 16. Prior or subsequent to the cutting operation, each piece 11 to 14 has a first row of holes 17 drilled along the edge margin which provides the flange 16, and, parallel to these, a further row of holes 18 drilled in a central region of each panel portion 15. This further row of holes 18 is generally midway between the fold line 19 and a panel edge 20 opposing the fold line 19, but, as shown, slightly closer to the edge 20. These holes 17, 18 are, of course, for the purpose of connection of the pieces 11 to 14 by bolts.

In a subsequent operation, which may conveniently be on-site where the assembled pile sleeve is required, the pieces 11 to 14 are connected together in the symmetrical arrangement shown in figure 1 with the flange 16 of each piece 11 to 14 being connected to the longitudinal central region of the adjacent piece by bolting through the respective holes 17, 18 of the respective pieces. For this purpose a series of coach bolts with a dome top may be employed with a square plug fitted into each square hole 17 so that an installer only needs to use one spanner to assemble them. However, bolt connections 23 are depicted only schematically in figure 1. Naturally, the bolt size (and the size of holes to accommodate them) can be varied to suit the thickness of the steel plate used to produce the pieces 11 to 14.

Although only three holes 17, 18 have been shown in each row of holes in the illustrated embodiment, it will be appreciated that the number of holes and accordingly the number of bolts can be increased or reduced depending on the specific requirements for the dimensions of the winged pile and the steel sheet from which it is produced. Also, in modified embodiments, additional rows of holes may be drilled parallel to the fold line 19 in order that the position of attachment of the respective pieces 11 to 14 to each other can be selected to obtain different sizes of the central passage 20 to accommodate differing diameters of pile 30.

In providing the obliquely cut corner edges 25, which provide the taper at the leading end of the assembled sleeve, a square piece 26 remains at the centre of the cutting pattern shown in figure 4. This piece 26 is shown with a hole cut out of its centre. It can usefully be employed as a washer fitted over the tubular pile 30 to protect the top of the wings when they are being hammered into the ground. This allows the winged sleeve to be pushed in by, for example, an excavator, precluding the need for a hydraulic hammer or excavator mounted vibrator. The cutting pattern shown in figure 4 minimises waste, thus improving fabrication efficiency and resulting in cost savings. The dimensions of each wing and the degree to which each wing tapers can, of course, be varied during fabrication to suit the site conditions and assist installation.

The true rigidity of the winged sleeve's construction is achieved when it is loaded over the tubular pile, as shown in Figure 1.

In some situations resistance to lateral load is required in one direction only, in which case making all the wings of the pile sleeve of equal size is wasteful of material and of effort in driving the wings into the ground. Accordingly, for such a situation a modified version of winged pile sleeve as shown in figure 5 could be used. In this version, two opposing pieces 11, 13 are of the same shape and size as in the previous embodiment with panel portions 15 of a size to provide projecting wings (projecting beyond the central sleeve of rectangular cross-section), but the other two pieces, designated 112, 114 have had their panel portions 15 shortened to just beyond the bolted connection 23 to the flanges 16 of the other pieces 11, 13. Accordingly, they still provide sides to the central passage 20 and the necessary structural rigidity of the sleeve, but do not provide unnecessary projecting wings. In other embodiments of the invention, other combinations of shorter and longer wings may be provided by the respective pieces having panel portions of different lengths, but requirement for such embodiments may be limited as in most circumstances there is a requirement to resist wind load which is multidirectional.

Claims

CLAIMS1. A winged pile sleeve for location around a section of a pile, the pile sleeve being assembled from four pieces, each comprising a substantially planar panel having a substantially perpendicular flange along one side edge, the panels being connected together so that the flange of each piece is secured to a longitudinal region of the panel of the adjacent piece, spaced apart from the flange of the adjacent piece, so as to define a passage of substantially rectangular cross-section through the centre of the assembled sleeve whereby the sleeve is fitted over the pile section and at least some of the panels extend beyond said connection to provide wings projecting outwards from the pile sleeve.
2. A pile sleeve according to claim 1 wherein each panel has an oblique edge along a side remote from the flange, these oblique edges providing a taper at a leading end of each wing of the pile sleeve.
3. A pile sleeve according to claim 1 or 2 wherein the pieces are of substantially identical size and shape.
4. A pile sleeve according to any of claims 1, 2 and 3 further comprising a plate fitted across a trailing end of the passage and adjacent regions of the trailing end of the wings.
5. A pile sleeve according to claim 4 wherein the plate is provided with an aperture so as to fit around the pile when the sleeve is located thereon.
6. A winged pile sleeve for location around a section of a pile, the pile sleeve being assembled from four pieces which are connected together in a symmetrical arrangement, each comprising a substantially planar panel having a substantially perpendicular flange along one side edge, the flange of each piece being connected to a longitudinal region generally midway between the flange and an opposing edge of the adjacent piece so as to define a passage of substantially rectangular cross-section through the centre of the assembled sleeve whereby the sleeve, in use, is fitted over a pile section, while the respective panels project outwards beyond said connection to provide the wings of the pile sleeve.
7. A winged pile sleeve substantially as hereinbef ore described with reference to and as illustrated by figures 1 to 3 or figure 5 of the accompanying drawings