EP0247099A1

EP0247099A1 - Device for taking the impression of elements of immersed structures and method using said device

Info

Publication number: EP0247099A1
Application number: EP19860906753
Authority: EP
Inventors: Roger Genet; François Lazare
Original assignee: Irete SA
Current assignee: Irete SA
Priority date: 1985-12-02
Filing date: 1986-12-01
Publication date: 1987-12-02
Also published as: WO1987003318A1

Abstract

Dispositif pour la prise d'empreinte d'éléments de structures immergées tels des noeuds de ramifications se composant d'un élément principal (1) et d'un ou de plusieurs éléments secondaires (2, 3,4...). Ce dispositif comprend des éléments de coffrage préformés rigides (7, 8, 9...) coopérant deux à deux par leurs arêtes (7a/8a, 8b/9b, 9c/10c...) et dont l'une des parois (11, 12, 13...) formant cloison est agencée pour prendre appui par sa tranche sur la surface d'un ou de plusieurs éléments (1, 2, 3, 4...) selon leur axe longitudinal, pour former autour de l'élément de structure considéré une enceinte compartimentée (15) ouverte vers le haut et présentant des passages (16, 17, 18...) épousant le pourtour desdits éléments (1, 2, 3, 4...). Il comprend en outre des moyens (20) pour fixer entre eux lesdits éléments de coffrage (7, 8, 9...) et des moyens (21) pour amener une composition liquide polymérisable (22) à la zone inférieure de chacun des compartiments ainsi délimités.Device for taking the impression of elements of submerged structures such as branch nodes consisting of a main element (1) and one or more secondary elements (2, 3,4 ...). This device comprises rigid preformed formwork elements (7, 8, 9 ...) cooperating two by two by their edges (7a / 8a, 8b / 9b, 9c / 10c ...) and one of whose walls ( 11, 12, 13 ...) forming a partition is arranged to bear by its edge on the surface of one or more elements (1, 2, 3, 4 ...) along their longitudinal axis, to form around the structural element considered a compartmentalized enclosure (15) open upwards and having passages (16, 17, 18 ...) conforming to the periphery of said elements (1, 2, 3, 4 ...). It further comprises means (20) for fixing between them said shuttering elements (7, 8, 9 ...) and means (21) for bringing a polymerizable liquid composition (22) to the lower zone of each of the compartments thus delimited.

Description

1 Device for taking the impression of elements of submerged structures and method using such a device

The invention relates to a device for taking the impression of elements of submerged structures such as branching nodes for example, and to a method for taking the impression of such elements using this device.

All submerged engineering structures, pillars of bridges, dikes, dams or "offshore" drilling platforms, for example, are subject to the effects of corrosion sooner or later. Such effects are particularly felt on all metallic parts immersed in the marine environment and, depending on the extent of the corrosion, this often results in a mechanical weakening of the entire structure of the structure.

In addition to the harmful effects due to corrosion, such submerged structures are subject to the consequences of various mechanical stresses, such as gravity, repeated wave shock, pressure from underwater currents or traction on anchor points for example . "Off-shore" drilling platforms are relatively sensitive structures in this respect, both by their construction and by their exposure to natural elements. Under the effect of the swell, and this over long periods, constituent elements such as branch nodes are continuously subjected to tensile, compressive, even shear or twist forces. Most often having many welds, these branching nodes constitute weak points which should be checked regularly, reinforced, or even replaced if necessary.

When the problem of mechanical reinforcement or replacement of such structural elements arises, the following difficulty is very often encountered: after a more or less prolonged immersion time, this type of structural element has undergone deformations which it is appropriate however to respect so as not to compromise the stability of the whole. It n ^r is not uncommon, in fact, that several centimeters inflections are observed on bars or tubes; moreover, in the case of very large structures, construction cannot be carried out faithfully in relation to the construction plans drawn up. It follows that one cannot refer, or at least to a sufficient extent, to the accuracy of the initial co-construction plans for reconstructing structural elements to be replaced, or quite simply for adapting certain reinforcement devices.

Current underwater metrology techniques are currently difficult to apply to the measurement of structures as complex as branch nodes, especially when it comes to the reconstruction of three-dimensional structures. Such techniques also require the prolonged stay of divers, most often at great depths, which proves to be very dangerous and very expensive; furthermore, the accuracy required by the builders cannot be ensured with the aid of the readings thus practiced.

To carry out the measurement and the reconstruction of elements of submerged structures such as branching nodes, it is important for those skilled in the art to have readily applicable, non-dangerous and safe technical solutions. This is advantageously achieved using the device according to claim 1, by proceeding as indicated in claim 5.

It has in fact been found that such a device, implemented according to the method of the present invention, is advantageously suitable for the measurement of highly complex submerged structural elements, such as branching nodes of support elements, beams or tubes, supporting "off-shore" drilling platforms for example.

. The appended figures illustrate, by way of example only, an embodiment of the device according to the invention. 3

Pig. 1 is an exploded view showing the device in the process of being assembled around a ramifications node.

Fig. 2 shows the device assembled around said branch node.

Fig. 3 is an exploded view showing the elements of polymerized material obtained using the device according to the invention and used for the 'reconstruction of the branch node.

According to the invention, the device comprises rigid preformed formwork elements 7,8,9 ... cooperating in pairs by their edges 7a / 8a, 8b / 9b, 9c / 10c ... and one of the walls of which 11,12,13 ... forming a partition is arranged to bear by its edge on the surface of one or more elements 1,2,3,4 ... along their longitudinal axis. Once assembled around the structural element concerned, said shuttering elements constitute a compartmentalized enclosure 15 having passages 16,17,18 ... spanning the periphery of said elements 1,2,3,4 .. ..

For obvious practical reasons, the construction of the device will preferably be designed in such a way that the upper surface of the enclosure is entirely free. In order to ensure the best possible resistance of the assembled elements, the edges 7a, 8a, 8b, 9b ... will be suitably shaped: they may have male profiles, respectively female profiles, cooperating with the corresponding profile of the edge of the neighboring element, as illustrated in FIGS. 1 and 2.

According to the invention, at least one of the walls constitutive of the shuttering formwork elements, dividing the enclosure 15 into as many separate compartments as necessary. For such purposes, said walls (11,12,13 ... in the particular embodiment illustrated by FIGS. 1 and 2) are arranged to bear by their edges on the surface of an or. several elements of the submerged assembly considered. In order to allow easy demolding and a faithful reconstruction of the spatial model to be reproduced, said walls will also be arranged so as to bear along the longitudinal axis of the elements 1,2,3 ... According to the invention, each of said formwork elements has, on at least part of its edges, one or more recesses arranged so as to coincide with one or more corresponding recesses of the neighboring formwork element, thus forming passages 16, 17,18 ... whose axis of symmetry is most generally represented by the edge common to two assembled elements. Said passages 16,17,18 ... are shaped so as to marry the periphery of one or more elements 1,2,3,4 ..., tubes or beams for example, of the submerged structure.

The construction of such formwork elements poses no particular problems; it is easily carried out using the usual techniques. Pre-forming, moreover, is easily carried out from the construction plans of the structural elements concerned, at least with sufficient accuracy so that their installation is done without difficulty.

According to the invention also, the periphery of the passages 16,17,18 ..., the edge of the walls 11,12,13 ... of the formwork elements bearing on the elements 1,2,3,4 ... and, where appropriate, the edges 7a, 8a, 8b, 9b ... through which said formwork elements cooperate, are provided with elastic seals 23.

Such seals have the effect of absorbing the inevitable disparities in construction according to plans and the real situation encountered on the spot. The practice will determine the amplitude of the variations to be thus absorbed, consequently the thickness of the seals 23 to be placed. Such seals are most generally made of elastic polymerized material, such as polyurethane foam, polypropylene, pol butadiene, natural or synthetic rubber for example.

To facilitate handling in a liquid medium, the formwork elements will preferably be made of a material having a density substantially close to that of the ambient liquid medium: it may be simple or composite materials, such as agglomerated wood, polyester reinforced with glass fibers for example, suitably ballasted if necessary with metallic elements. Depending on the case, steel formwork elements can also be used, the latter then being maintained in suspension using floats or, as far as possible, retained from the surface by cables or any other appropriate means.

To ensure the establishment as well as their evacuation from the workplace, said elements pour¬ ront be further provided with additional attachment or gripping means 24, arranged for example at their upper end superior.

According to the invention, the device comprises means 20 making it possible to fix together the formwork elements 7,8,9 ... assembled. Any suitable known means such as a latch, "clip", screw system or bolt for example, can be used for such purposes. These means will be designed to temporarily assemble the formwork elements.

According to the invention further, the device comprises means 21 making it possible to bring to the lower zone of each of the compartments thus delimited a poly erisable liquid composition 22. As means 21, it is possible for example to use a connected injection pump to a conduit whose lower end opens out near the bottom of the enclosure 15, inside the latter. The simplest solution consists in using a flexible hose, of sufficient diameter, bringing the liquid composition 22 from the surface.

According to the invention, said liquid composition has a density ^{^} higher than the surrounding liquid medium. Using the means described above, it is brought to the lower zone of each of the compartments of the enclosure 15, these then being gradually filled by the bottom, the liquid composition 22 driving the water upwards. , as it arrives. By proceeding in this way, an undesired mixing of the liquids present can be avoided, which can lead to the formation of emulsions, if necessary, homogeneity defects of the mass 22 once polymerized. The density is adjusted in a way

β usual, at. using commercial products. Said liquid composition also has the characteristic of polyerizing, under the conditions of the ambient environment, without shrinkage: it is on this condition that the fidelity of the molding thus practiced can be guaranteed, consequently the exac¬ titude of the measurements of the structural elements considered. The liquid composition must also have the characteristic of generating a polymerized mass 22 which does not adhere to the metal or to the concrete constituting the mass of the elements 1,2,3,4 ... This characteristic poses no problem, because it is in fact found in a large number of compositions generating polymerized material.

As a liquid composition according to the invention, it is advantageously possible to use mixtures with two components, generating epoxy resins or polyurethanes, optionally mixed with various additives such as ballast substances, polymerization retardants or dyes for example . The main thing is to obtain a liquid composition which polymerizes under water and whose characteristics can be adapted at any time to the requirements set out previously: the skilled person can easily do this, using commercial products. specialized.

The implementation of the device according to the invention is carried out as follows:

- We bring, using any appropriate means, rigid preformed formwork elements 7,8,9, ... at the height of the structural element concerned;

- they are assembled two by two by their edges

7a, 8a, 8b, 9b, c ... to form a compartmentalized enclosure 15 open upwards, the walls 11,12,13 ... forming a partition being supported by their edges on the surface of one or more elements 1,2,3,4 ... along their longitudinal axis and some of the faces of which allow said elements 1,2,3,4 ... to pass through passages 16,17,18 ...;

- Then each of the compartments of the enclosure 15 thus delimited is filled with a liquid composition 22 polymerizing ^' without shrinkage, from their lower zone;

- Finally, the polymerized mass 22 is released from the elements 1,2,3,4 ... with which it was in contact. In order for said polymerized mass to be separated into as many parts as there are compartments, it will be ensured that the maximum filling level of said compartments is located below the upper surface of the enclosure 15.

In order to facilitate the release of the mass 22 from the structural elements thus molded, the latter can be coated beforehand with a non-stick liquid film, such as a silicone oil for example. The same can be done with regard to the internal face of the shuttering elements or cover the latter with a polymer film having a weak adhesion with respect to the polymerized mass 22, a polyester sheet for example. Such operations are however not essential for the proper implementation of the invention.

For the same purpose, the device according to the invention, each of the compartments of the enclosure 15 may be provided, with means 25 allowing a pressurized fluid, compressed air for example, to be brought into contact with the surface of the structural elements intended to be taken from the polymerized mass 22. The use of such additional means can be justified at great depths.

Once the portions of polymerized mass 22 have risen to the surface and assembled in accordance with the spatial arrangement determined by the compartmentalized enclosure 15, it is easy to reproduce the identical structural element considered. It has also been found that with the aid of said mass portions 22, it was also possible to control the surface condition of the elements of the submerged structure, and in particular the quality of the metal welds.

Claims

1. Device for taking the impression of elements of submerged structures such as branch nodes consisting of a main element (1) and one or more secondary elements (2,3,4 ...), characterized in that it comprises rigid preformed formwork elements (7,8,9 ...) cooperating two by two by their edges (7a / 8a, 8b / 9b, 9c / 10c.) and one of which walls (11,12,13 ...) forming a partition is arranged to bear by its tran¬ che on the surface of one or more elements (1,2,3,4 ...) along their longitudinal axis, to form around the structure element considered a compartmented enclosure (15) open upwards and having passages

(16,17,18 ...) matching the periphery of said elements (1,2,3,4 ...), in that it comprises means (20) for fixing between them said formwork elements (7, 8.9 ...) and in that it comprises means (21) for bringing a poly erisable liquid composition (22) to the lower zone of each of the compartments thus delimited.

2. Device according to claim 1, caracté¬ ized in that the periphery of the passages (16,17,18 ...), the edge of the walls (11,12,13 ...) of the formwork elements resting on the elements (1,2,3,4 ...) and, where appropriate, the edges (7a, 8a, 8b, 9b ...) by which said formwork elements cooperate, are provided with seals elastic seals (23).

3. Device according to one of claims 1 and

2, characterized in that the shuttering elements are pour¬ seen with gripping or hooking means (24).

4. Device according to one of claims 1 to

3, characterized in that it comprises means (25) for bringing a pressurized fluid into contact with the surface of the portions of elements (1,2,3,4 ...) located inside the pregnant (15).

5. Method for taking the impression of elements of submerged structures such as reunification nodes consisting of a main element (1) and one or more secondary elements (2,3,4 ...), characterized in that it consists in bringing dice rigid preformed formwork elements (7,8,9 ...) to the height of the structural element concerned, to assemble them two by two by their edges (7a, 8a, 8b, b, 9c.) to form a compartmentalized enclosure (15) open upwards, the walls (11,12,13 ...) forming a partition being supported by their edge on the surface of one or more elements (1,2,3,4 ...) along their longitudinal axis and some of the faces of which allow said elements to pass (1,2,3,4 ... ) through passages (16,17,18 ...), then fill with a liquid composition (22) polymerizing without shrinking each of the compartments thus delimited, from their lower zone, and to release then elements (1,2,3,4 ...) the mass (22) once it poly¬ merized.

6. Method according to claim 5, characterized in that the liquid composition (22) has a density greater than that of the ambient medium.

7. Method according to one of claims 5 and 6, characterized in that the liquid composition (22) is generating a polymerized mass which does not adhere to the elements U _/ - " _f ^ 4 _* •" _•

8. Method according to one of claims 5 to 7, characterized in that the maximum filling level of the compartments of the enclosure (15) is located below the upper surface of said enclosure.

9. Method according to one of claims 5 to 8, characterized in that the shuttering elements (7,8,9 ...) have a density substantially equal to that of the ambient liquid medium.