GB2220432A

GB2220432A - Driving hollow piles to form an underwater foundation

Info

Publication number: GB2220432A
Application number: GB8910864A
Authority: GB
Inventors: Paolo Veronelli; Mauro Gazzola
Original assignee: MICOPERI SpA
Current assignee: MICOPERI SpA
Priority date: 1988-07-08
Filing date: 1989-05-11
Publication date: 1990-01-10
Also published as: GB8910864D0; IT8821286A0; NO891564D0; NO891564L; IT1226227B

Abstract

A method for the production of an underwater foundation utilising hollow piles (1) comprises equipping the piles with a provisional reinforcement (8) in such a manner that they are temporarily stiffened while being driven into the seabed by a pile driver (10). <IMAGE>

Description

METHOD OF PRODUCING AN UNDERWATER FOUNDATION The present invention relates to a method of producing an underwater foundation, in particular a foundation utilising hollow piles.

Hollow piles are especially suitable for resisting forces acting in direction of their axis. During the ramming-in of such piles, however, buckling stresses which are not readily absorbed by the piles are created by the effects of the pile ram and by the forces originating from the seabed.

It would thus be desirable to eliminate this disadvantage so as to ensure satisfactory driving in of piles under the blows of a pile driver.

According to the present invention there is provided a method of producing an underwater foundation, comprising the steps of providing a plurality of hollow foundation piles, equipping each pile with a temporary reinforcement to temporarily stiffen the pile, and driving the piles into place while so stiffened.

In a preferred example of the method, a substantially cylindrical insert, which is pushable into each pile, is used as the reinforcement.

The reinforcement preferably remains locally fixed in its position as long as it is inserted in the pile during the driving.

For preference, each pile is provided with the reinforcement when it has been brought into its driving position and before driving has begun. The reinforcement is then slidingly removed from the pile before completion of the driving, in particular before the pile driver could strike the reinforcement.

An example of the method of the present invention will now be more particularly described with reference to the accompanying drawings, in which: Figs. 1 to 6 are views of an underwater foundation in different phases of production by a method exemplifying the invention; and Fig. 7 is a detail view, to an enlarged scale, of a pro visional reinforcement used in the method.

Referring now to the drawings, there are shown different stages in production of an underwater foundation for a structure serving the purpose of exploration or extraction, but the foundation can serve for other purposes. Fig. 1 illustrates in detail the introduction of a hollow foundation pile 1 into a sleeve 2, which is provided with a funnel-shaped introduction cone and is firmly connected with a frame 3 resting on the seabed 4 but protruding above the sea level 5. By this introductory step, which is carried out with the aid of a floating crane 6, the pile 1 spontaneously penetrates by a small amount 7 into the seabed.

Fig. 2 illustrates the introduction into the pile 1 of a provisional reinforcement 8, which is in the form of a substantially cylindrical insert. The reinforcement is provided with a handle 9 to facilitate its manipulation.

A pile driver 10 is then mounted on the foundation pile 1 (Fig. 3) and the pile is rammed into the seabed by the blows from the pile driver (Fig. 4). Fig. 5 illustrates the removal of the provisional reinforcement, which until then is supported on the seabed, and Fig. 6 illustrates the concluding ramming-in of the pile and its final penetration into the seabed by the amount 11.

Details of the reinforcement and its positioning in the interior of the hollow foundation pile are shown in Fig. 7.

Claims

1. A method of producing an underwater foundation, comprising the steps of providing a plurality of hollow foundation piles, equipping each pile with a temporary reinforcement to temporarily stiffen the pile, and driving the piles into place while so stiffened.

2. A method as claimed in claim 1, whrein the reinforcement comprises a cylindrical insert pushable into the pile.

3. A method as claimed in claim 2, wherein the length of the insert is equal to only part of the length of the respective pile.

4. A method as claimed in any one of the preceding claims, wherein the reinforcement is disposed to rest on the bed of the underwater site during driving of the pile.

5. A method as claimed in any one of the preceding claims, wherein each pile is equipped with its reinforcement after that pile has been brought into position for driving into place but before such driving commences, the method comprising the step of removing the reinforcement from each pile before driving of the pile into place has been completed.

6. A method as claimed in claim 1 and substantially as hereinbefore described with ref erenoeto the accompanying drawings.