WO1998021414A1

WO1998021414A1 - Improvements relating to pile protection

Info

Publication number: WO1998021414A1
Application number: PCT/GB1997/003114
Authority: WO
Inventors: Ernest Coutts
Original assignee: N.I.C.C. Limited
Priority date: 1996-11-13
Filing date: 1997-11-13
Publication date: 1998-05-22
Also published as: GB9623599D0

Abstract

Cladding for the junction of a pile (5) with the underside of a structure (2) supported by that pile (a soffit (3)) comprises an encapsulation with an outer waterproof skin or shell and a gel-impregnated inner felt layer. This is shaped to have a flange (8) that engages the soffit (3) and a skirt (9) which fits closely around the top of the pile (5). It is secured by a split collar (7) which underlies the flange (8), fasteners (12) being entered through apertures (11) in the collar (7), and preferably through the flange (8) as well, to engage in the soffit (3).

Description

Improvements relating to Pile Protection

This invention relates to pile protection, and is concerned with the cladding of the legs of structures such as oil rigs piers or jetties standing on the seabed but projecting above water level to support a platform or other structure .

There have been various proposals for placing a jacket around a pile to seal its surface off from exposure to air and water, such as in EP-B-0295254. There is however a problem at the top of the pile, where it joins the platform. The typically cylindrical jacket usually stops just short, leaving a small length of pile exposed. A crude cure for this is simply to wrap it round with felt impregnated with waterproof gel of the kind that forms the inner layer of the wrapping of EP-B-0295254. However, this is accepted only because there is nothing better, and it is the aim of this invention to provide an improved cladding for this area.

According to the present invention there is provided a cladding for the junction of a pile with the underside of a structure supported by that pile (hereinafter the soffit) , the cladding comprising a waterproof encapsulation clampable around the pile to have an overlap of the meeting edges to sheath the top portion of the pile and to have an outwardly projecting flange co-operating closely with the soffit, and a split collar which can be arranged freely to embrace the pile and having apertures to receive fasteners for clamping the flange to the soffit by the collar.

The flange may also be apertured so that the fasteners pass through it to make it more positively captive.

The encapsulation will preferably be similar to the wrapping of EP-B-0295254, with a flexible rubber or plastic- based outer skin and an inner layer of felt impregnated with gel. The outer skin will be moulded to the intended final shape. Alternatively, there could be a metallic outer shell of that shape, with a gel -impregnated felt lining.

When this cladding is in place, a wrapping such as that of EP-B-0295254 is fitted around the pile, its upper end overlapping the part of the jacket that surrounds the pile. The wrapping is drawn tight and secured, making a waterproof circumferential seal with the jacket.

For a better understanding of the invention, one embodiment will now be described, by way of example, with reference to the accompanying drawing, in which the single figure is an underneath perspective view of the top of a pile and the_. soffit of a platform supported thereby, with cladding partially in place.

A pile 1 supports a platform 2 with a soffit 3. In this example, the cross-section of the pile is rectangular with rounded corners, but it will be understood that different shapes occur, and that cylindrical piles are common. The shape of the cladding to be described will vary accordingly. The pile will be largely sheathed by wrappings 4 such as those of EP-B-0295254, and one of these is shown, with an intermediate cummerbund 5 for sealing to the next one down. This top wrapping is not shown in its final position. First a cladding 6 is put in place and secured by a two part support collar 7. The cladding is constructed similarly to the wrapping 4, with an outer waterproof skin and a gel -impregnated inner felt layer, but is moulded to have a flange 8 and a skirt 9. It is not formed as a closed loop (it could not then be fitted) but with separate ends that overlap at 10. It will naturally assume the shape shown, the skirt 9 fitting snugly around the top of the pile 1 and the flange 8 abutting the soffit 3. The two parts of the support collar 7 are U-shaped and together they can loosely embrace the pile 1. They have apertures 11 for fasteners 12 and the soffit 3 is prepared with apertures and plugs (not shown) to receive these. The collar is placed under the periphery of the flange 8 and the fasteners 12 are secured so that the flange is clamped to the soffit 3, making a waterproof seal all round.

With the cladding 6 now in place, the wrapping 4 is fitted, overlapping the skirt 9 to seal around that. A clamping device 13 and bolts 14 for respectively applying the hoop tension and holding the wrapping are shown. The upper end of the pile 1 is thus fully protected.

It will be understood that it may be convenient for the collar to be in more than two parts, and those parts need not necessarily be U-shaped. For example a satisfactory collar could be made from four straight flat bars arranged in a rectangle.

As mentioned above, the cladding 6 could have a metallic outer shell rather than a rubber or plastic-based outer skin. It might be possible to have a unitary shell which could be sprung around the pile, but it is probable that it would have to be in two parts (like the illustrated collar 7) that are brought together with two overlapping joints.

Claims

CLAIMS 1. A cladding for the junction of a pile with a soffit, the cladding comprising a waterproof encapsulation clampable around the pile to have an overlap of the meeting edges to sheath the top portion of the pile and to have an outwardly projecting flange co-operating closely with the soffit, and a split collar which can be arranged freely to embrace the pile and having apertures to receive fasteners for clamping the flange to the soffit by the collar.

2. A cladding as claimed in Claim 1, wherein the flange is also apertured so that the fasteners pass through it.

3. A cladding as claimed in Claim 1 or 2 , wherein the encapsulation has a flexible rubber or plastic-based outer skin and an inner layer of felt impregnated with gel.

4. A cladding as claimed in Claim 3, wherein the encapsulation is moulded to the shape it is intended to assume in use .

5. A cladding as claimed in Claim 1 or 2 , wherein the encapsulation has a metallic outer shell with a lining of felt impregnated with gel.