EP0241346B1 - Removable and earth quake-proof partition wall - Google Patents

Description

The invention relates to a removable and earthquake-resistant partition intended to close an opening formed in a vertical wall and in particular in a wall of a room containing radioactive materials.

In nuclear plants, access to the rooms containing radioactive materials are generally closed by partitions formed by a dry stack (without mortar) of concrete bricks.

While ensuring the continuity of protection against radiation emitted by radioactive materials that are inside the room, these partitions allow to intervene inside the room if necessary, thanks to their removable nature .

The dimensions of the openings closed by these removable partitions vary according to whether they are intended to allow the passage of a person or of materials. In the first case, these dimensions are generally 1 m x 1.80 m. In the case of an opening for the passage of materials, the dimensions of the openings can go up to 5m x 4m.

Like all elements of nuclear plant buildings, these demountable partitions are designed so as to be able to withstand the effects of an earthquake, when required by safety analysis.

In the current state of the art, the bricks constituting these demountable partitions are generally in the form of rectangular parallelepipeds with flat faces. Resistance to the horizontal inertia forces perpendicular to the partition that can be produced by an earthquake is obtained by having a supporting frame on either side of the brick stack. Depending on the case, this framework is formed by a general sheet metal work or by a grid of metal profiles.

These known demountable partitions, however, have a number of drawbacks.

Firstly, their cost is high because the price of the supporting frame can be higher than that of the stack of bricks.

In addition, access to the room is made difficult by the support frame, which dismantling is added to that of the stack of bricks.

Finally, the presence of a support frame inside the room makes decontamination more difficult, especially when this frame is made of profiles. Indeed, the decontamination procedure is all the more delicate as the wall of the structure to be decontaminated is not smooth.

Document FR-A-1 232 638 also discloses a partition made of bricks, the shape of which ensures protection against radiation. The bricks are sealed together and crossed by vertical and horizontal metal bars which constitute a framework ensuring resistance to earthquakes. However, this partition is not removable.

The present invention specifically relates to a removable partition and resistant to earthquakes of a new type, not having the drawbacks which have just been mentioned of existing removable partitions.

Thus, in accordance with the invention, a demountable and earthquake-resistant partition is proposed, closing off an opening formed in a vertical wall, said partition comprising at least two layers of parallelepiped bricks arranged in superimposed horizontal rows, characterized in that each of said rows comprises at least one central locking brick having a horizontal section in the form of an isosceles trapezium, and bricks having a horizontal section in the form of a parallelogram and arranged symmetrically on either side of the central locking brick, all the central bricks for locking the same layer being oriented in the same direction, so that each of the series of bricks behaves like a fictitious funicular arc when the partition is subjected to a horizontal force exerted perpendicular to said partition, in a first direction going from the big base to the pet ite base of the trapezoid formed in horizontal section by the central locking brick of each series, the layers of bricks constituting the two external faces of the partition being formed so that the small bases of the trapezoids formed in horizontal section by the central bricks of locking these layers are placed on said external faces. Thus, the two holding structures according to the prior art are eliminated without affecting the demountability of the partition.

Such a demountable partition is designed mainly to be placed in a wall of a room containing radioactive materials. However, it can also be used outside the nuclear industry, in all cases where an opening must be able to be made relatively easily in a wall or a vertical wall which must moreover have good resistance to earthquakes. Therefore, if the bricks are preferably made of heavy concrete, having a density higher than that of ordinary concrete, other materials such as ordinary concrete or refractory earth can also be used.

Preferably, the rows of bricks are offset vertically from one layer to another, to avoid leakage by radiation at the joints.

The bricks of two adjacent rows of the same layer can also be offset horizontally in a direction parallel to said partition, so as to increase the cohesion of the latter.

In a preferred embodiment of the invention, each of the bricks with a horizontal section in the shape of a parallelogram has a key on one end face and a recess of complementary shape to said key on an opposite end face, each of the bricks with horizontal section in the shape of an isosceles trapezoid having on end faces corresponding to the sides of the trapezoid recesses of identical shape to that of the recess formed on bricks with horizontal section in the shape of a parallelogram, so that in each cune of said rows, each key is received in a recess of the adjacent brick.

When the width of the opening in which the demountable partition is located according to the invention is too large, each row of bricks comprises two series of bricks and an intermediate support brick interposed between said series and having a horizontal section in the form of isosceles trapezium, the intermediate support bricks being oriented in opposite directions with respect to the central locking bricks of the same layer, a vertical retaining profile being fixed to the wall so as to be pressed against the large base of the trapezium formed in section by each of the supporting bricks, this large base of which is placed on an external face of the partition.

The support bricks are then identical to the central locking bricks. It is desirable for the partition to include locking pieces capable of simultaneously filling the recesses formed on the end faces of the support bricks and on the adjacent end faces of the bricks of horizontal section in the shape of a parallelogram.

During assembly, a mortar frame is poured between the bricks placed on the periphery of the partition and the opening formed in the wall.

To facilitate the dismantling of the partition, the mortar can be replaced by a packing of lead tow between the upper row of bricks and the upper part of the opening formed in the wall.

• - la figure 1 est une vue en coupe horizontale illustrant un premier mode de réalisation de la cloison démontable selon l'invention, dans lequel la cloison comprend deux couches de briques juxtaposées,
• - la figure 2 est une vue en élévation, depuis l'intérieur de la salle, illustrant une variante du mode de réalisation de la figure 1,
• - la figure 3 est une vue en coupe verticale selon la ligne III-III de la figure 2,
• - la figure 4 est une vue en coupe horizontale analogue à la figure 1 illustrant un deuxième mode de réalisation de l'invention dans lequel la cloison démontable comprend trois couches de briques juxtaposées, et
• - la figure 5 est une vue en coupe horizontale analogue aux figures 1 et 3, illustrant un autre mode de réalisation de l'invention, dans lequel la cloison démontable est située dans une ouverture de plus grande largeur et comprend un appui vertical intermédiaire.

Various embodiments of the invention will now be described, by way of non-limiting example, with reference to the appended drawings in which:

• FIG. 1 is a horizontal section view illustrating a first embodiment of the removable partition according to the invention, in which the partition comprises two layers of juxtaposed bricks,
• FIG. 2 is an elevation view, from inside the room, illustrating a variant of the embodiment of FIG. 1,
• FIG. 3 is a view in vertical section along the line III-III of FIG. 2,
• FIG. 4 is a horizontal sectional view similar to FIG. 1 illustrating a second embodiment of the invention in which the removable partition comprises three layers of juxtaposed bricks, and
• - Figure 5 is a horizontal sectional view similar to Figures 1 and 3, illustrating another embodiment of the invention, in which the removable partition is located in an opening of greater width and comprises an intermediate vertical support.

Figure 1 shows a portion of a wall or wall 10, approximately vertical, for example of reinforced concrete, in which is formed an opening 12, of generally rectangular shape.

The verticality of the wall 10 is not necessarily rigorous. Indeed, it will be readily understood that the invention also applies to the case of walls having a slight inclination relative to the vertical.

Furthermore, the shape of the opening 12 is not necessarily rectangular, even if it is generally openings of this shape that are produced in practice.

According to the invention, the opening 12 formed in the wall 10 is closed by a removable partition 14 designed to resist earthquakes. In addition, when the wall 10 delimits a room 11 containing radioactive materials, the partition 14 is designed so as to provide protection against the radiation emitted by the radioactive materials which are inside this room.

In FIG. 1, these two objectives are achieved by means of an adjoining and dry stack, that is to say without mortar, of concrete bricks 16 and 18 arranged in this case in the form of two juxtaposed layers. The thickness of each of these layers is, for example, 20 cm or 30 cm. Each layer is formed by several horizontal rows of bricks 16 and 18 all having in horizontal section the shapes illustrated in FIG. 1.

The bricks 16 and 18 are all of parallelepiped shape and have flat and horizontal lower and upper faces, their height being, for example 10 cm.

As illustrated in FIG. 1, each of the rows comprises a series of bricks formed by a central locking brick 18, having in horizontal section the shape of an isosceles trapezoid, and bricks 16 having in horizontal section the shape of parallelograms , these bricks 16 being arranged in equal number and in opposite directions, on either side of the central brick 18.

If the end faces are the adjacent faces of the bricks 16 and 18 of the same row, the end faces 18a of the bricks 18 correspond to the sides of the trapezoids formed in horizontal section by these bricks 18. The end faces of the bricks 16 are designated by the reference 16a. The length of the bricks 16 is, for example 30 cm, the length of the bricks 18 possibly being 15 cm and 25 cm, depending on whether one looks at them from the side of the small base or from the side of the large base of the trapezoid that 'they form in horizontal section.

The external faces of the bricks 16 and 18 are designated respectively by the reference 16b for the bricks 16 and by the references 18b and 18'b for the faces of the bricks 18 corresponding to the small base and to the large base of the trapezoid formed in section by these bricks.

In addition, the angles formed between the faces 18a, 18b and 18'b of the central locking bricks 18 are the same as the angles formed between the faces 16a and 16b of the bricks 16. By reversing the direction of the bricks 16 on the part and d Another of the central brick 18, as illustrated in FIG. 1, the end faces 16a and 18a of the bricks 16 and 18 of each row are thus supported on the end faces of the adjacent bricks.

In Figure 1, each of the two layers of bricks is made in the same way. However, the two layers of bricks are arranged in opposite directions, so that the small faces 18b of the central locking bricks 18 are located on the two external faces 14b and 14'b of the partition 14.

So that the installation of the bricks 16 and 18 can be done without difficulty, there are spaces between the interior surfaces of the vertical and horizontal uprights of the opening 12 and the external faces of the bricks 16 placed at the periphery of the partition 14 In the embodiment shown, keying mortar 20 is poured into these spaces to form horizontal beds and vertical supports on which the stack of bricks is supported. As a variant, the space delimited between the upper rows of bricks and the horizontal upper upright of the opening 12, in which a blocking is not necessary, can be filled by a stuffing 21 made of lead tow (Figures 2 and 3 ).

Thanks to the vertical supports formed by the mortar 20 interposed between the end faces 16a of the bricks 16 placed at the ends of each row and the inner face of the opening 12, which is parallel to these end faces, the bricks 16 and 18 of each row of bricks behave like a fictitious funicular arch.

More precisely, the rows of bricks of one of the layers (on the left in FIG. 1) behave like a fictitious funicular arch when they are subjected to a horizontal load exerted perpendicularly to the partition in a first direction (arrow Fi in Figure 1). Conversely, the rows of bricks of the second layer (on the right in FIG. 1) behave like a fictitious funicular arc when the partition is subjected to a horizontal load exerted perpendicular to the partition in the opposite direction (arrow F ₂ on Figure 1). The corresponding fictitious funicular arches are represented diagrammatically by the hatched parts A ₁ and A ₂ in FIG.

In this way, no framework for holding the removable partition is necessary.

As also illustrated in FIG. 1, one of the end faces 16a of each of the bricks 16 preferably has a key 26 constituted by a projecting part extending vertically over the entire height of the brick and having a shape substantially trapezoidal in horizontal section.

The other end face 16a of each of the bricks 16, as well as the two end faces 18a of the bricks 18 have recesses 28 which also extend over the entire height of these bricks and have a horizontal trapezoidal section. These recesses 28 have a shape complementary to that of the keys 26, so that the latter are housed in the recesses of the adjacent bricks 16 or 18 of the corresponding row, as illustrated in FIG. 1.

It should be noted that the keys 26 are received in the recesses 28 with a certain clearance. They therefore do not participate in the transmission of the forces between the bricks when a force is applied according to the arrow Fi or the arrow F ₂ as is the case. described previously.

Figures 2 and 3 illustrate a variant of the embodiment of Figure 1.

In Figure 2, we see that the bricks 16 and 18 constituting each of the layers are staggered, that is to say offset from one row to another so that the joints that separate them are not aligned vertically .

This arrangement has the consequence that some of the parallelepiped bricks, designated by the reference 16 _' in FIG. 2 and placed alternately at each end of the rows of bricks, have a shorter length compared to the other parallelepipedic bricks 16. The length of these bricks 16 'is, for example, 10 cm.

Similarly, it can be seen in FIG. 3 that the rows of bricks 16 and 18 forming the two layers of the partition 14 are offset vertically, so that the planes of horizontal joints between these rows are not aligned in one layer to layer. This vertical offset can be, for example, half a brick height, that is to say about 5 cm if the height of the bricks is about 10 cm.

This last characteristic is particularly advantageous in the application of the invention to the production of a removable partition closing off the wall of a room containing radioactive materials. In fact, it provides effective protection against the radiation emitted by these materials.

FIG. 4 illustrates another embodiment of the invention comparable to that which has been described previously with reference to FIG. 1. In this embodiment, the removable partition 14 is made up of three layers of juxtaposed bricks, each of these layers being formed of overlapping horizontal rows.

In this case, the two layers forming the outer faces 14b and 14'b of the removable partition 14 are produced in a similar manner to those of the two layers forming the partition described with reference to FIG. 1 (possibly taking into account the variants of the figures 2 and 3). As for the intermediate layer between the two extreme layers, it is produced in a manner analogous to each of the other two layers, and oriented in the same direction as one of them (the right layer in FIG. 4) .

The bricks 16, 18 and possibly 16 'constituting the partition 14 of FIG. 4 are identical to those which have been described previously.

As clearly shown in FIG. 4, the presence of a greater number of juxtaposed brick layers (three in this case) makes it possible to produce thicker partitions 14. In addition, discontinuities are thus created between the layers between the joints formed between the end faces 16a and 18a of the bricks of the same row. In the case where the partition 14 closes an opening 12 formed in a wall 10 of a room containing radioactive materials, this further improves the protection against radiation.

Of course, this protection is also provided as described with reference to FIG. 3 by vertically shifting from one layer to the other the horizontal joints formed between two adjacent rows of the same layer.

Finally, Figure 5 illustrates another embodiment. tion of the invention in which the opening 12 to be closed by the removable partition 14 according to the invention has a width such that the mechanical strength of the vertical supports to which the force is transmitted in the event of an earthquake cannot be ensured without the addition of an intermediate vertical support.

In practice, the maximum width between supports is chosen so that the compression stress of the concrete of the fictitious arcs such as A ₁ and A ₂ in FIG. 1 remains less than a limit stress. This limiting stress is determined from the compression limit of the concrete. In the various embodiments described, in which the vertical supports include the keying mortar 20 which is unreinforced, not vibrated and difficult to put in place, an additional safety factor is applied to the compression limit of the concrete. The maximum width thus calculated is, for example, about 4 meters.

When the width of the opening 12 exceeds this maximum width, it is necessary to provide at least one intermediate vertical support. This situation is shown by way of example in FIG. 5 in the case of a demountable partition 14 comprising two layers of bricks each formed by a certain number of superimposed rows of bricks 16, 16 'and 18.

In this case, each row of bricks is formed of two identical series of bricks 16 and 18 placed end to end, so as to close off the entire width of the opening 12. Each of the two sets of bricks of the same row is produced in an identical manner to the rows of bricks constituting the partitions which have been described previously with reference to FIGS. 1 to 4.

More precisely, the two series of bricks in the same row are oriented in the same direction and separated by an intermediate support brick 18 'placed between the adjacent end bricks 16 of the two series. These support bricks 18 'are bricks having in horizontal section the shape of an isosceles trapezoid. They are preferably identical to bricks 18.

Given the orientation of the adjacent end faces of the bricks 16 between which the support bricks 18 'are placed, the face 18'b of these is located on the external face 14b or 14'b of the partition 14. Consequently, it is necessary to provide supports for transmitting to the wall 10 the forces collected by the bricks 18 'in the event of an earthquake.

As illustrated in FIG. 5, these supports are preferably constituted by vertical profiles 30 having for example an I-shaped section, placed so as to be able to withstand a force exerted perpendicular to the partition respectively in the direction of the arrow Fi or arrow F ₂ . The sections 30 are sealed at the top and bottom of the concrete wall 10 and they are in contact with the faces 18'b of the bricks 18 '.

In this way, when a force is exerted perpendicularly in the direction of the arrows F ₁ or F ₂ in FIG. 5, one or the other of the layers of bricks forming the partition 14 behaves row by row like two funicular arcs fictitious transmitting the force to which they are subjected for half to the vertical internal edges of the opening 12, via the concrete of keying 20, and for half to the profile 24, via the support bricks 18 ′.

As can be seen in FIG. 5, when the support bricks 18 'are identical to the intermediate bricks 18, the recesses 28 formed on the end faces of these bricks 18' are opposite corresponding recesses 28 formed on the adjacent end faces of the bricks 16. It is then desirable to place in the recesses facing the bricks 16 and 18 ′ locking pieces 32 simultaneously filling the two recesses facing each other.

- It should be noted that the retaining sections 30 are widely spaced and that their cost is much lower than that of the retaining framework required according to the prior art.

Of course, the invention is not limited to the embodiments which have just been described by way of example, but covers all variants thereof within the scope of the claims.

In particular, the embodiments described can be combined with one another, the use of intermediate vertical supports described with reference to FIG. 4 being able to apply as well to a partition formed of two layers of bricks as to a partition formed of three layers of bricks.

Furthermore, the keys formed on the bricks in the embodiments described have only a security role and can if necessary be deleted.

In addition, if the invention is particularly suited to the case of demountable partitions provided for sealing openings formed in the walls of rooms containing radioactive materials, it can also be used outside the nuclear industry.

Finally, the use of keying mortar can be avoided and replaced by complementary bricks of appropriate dimensions. The locking of the assembly is then ensured by means of at least one brick produced in several parts linked together by a removable connection means accessible from the outside, such as a screw.

Claims (8)

1. Earthquake-resistant, removable partition closing an opening (12) formed in a vertical wall (12), said partition (14) comprising at least two layers of parallelepipedic briks arranged in superimposed horizontal rows, characterized in that each of said rows comprises at least one series of bricks formed by a central locking brick (18) having a cross-section in isosceles trapezium form, as well as bricks (16, 16') having a cross-section in the form of a parallelogram and arranged symmetrically on either side of the central locking brick (18), whereby all the central locking bricks of the same layer are oriented in the same direction, so that each of the series of bricks behaves like a fictitious funicular arc (Ai, A₂) when the partition is subject to a horizontal force (F₁, F₂) exerted perpendicularly to said partition in a first direction passing from the large base towards the small base of the trapezium formed in cross-section by the central locking brick (18) of each series, the layers of bricks constituting the two outer faces (14b, 14'b) of the partition (14) being formed in such a way that the small bases of the trapeziums formed in cross-section by the central locking bricks (18) of said layers are placed on said outer faces.

2. Partition according to claim 1, characterized in that the rows of bricks are vertically displaced between individual rows.

3. Partition according to either of the claims 1 and 2, characterized in that the bricks (16, 16', 18) of two adjacent rows of a same layer are horizontally displaced parallel to said partition (14).

4. Partition according to any one of the claims 1 to 3, characterized in that each of the bricks (16, 16') with a cross-section in the form of a parallelogram has a key (26) of one end face (16a) and a recess (28) with a complementary shape to said key on an opposite end face (16a), each of the central locking bricks (18) having on end faces (18a) corresponding to the sides of the trapezium of recesses (28) with an identical shape to the recess (28) formed on the bricks (16, 16') with a cross-section in the form of a parallelogram, so that in each of said rows, each key (26) is received in a recess (28) of the adjacent bricks.

5. Partition according to any one of the claims 1 to 4, characterized in that each row of bricks comprises two series of bricks (16, 16', 18) and an intermediate support brick (18') interposed between said series and having a cross-section in the form of an isosceles trapezium, the intermediate support bricks (18) being oriented in the opposite direction with respect to the central locking bricks (18) of the same layer, at least one vertical retaining section (30) being fixed to the wall (10) so as to bear against the large base of the trapezium formed in section by each of the support bricks (18'), whereof said large base is placed on an outer face (14b, 14'b) of the partition (14).

6. Partition according to claims 4 and 5, characterized in that the support bricks (18_') are identical to the central locking bricks (18), said partition having locking members (32) able to simultaneously fill the recess (28) formed on the end faces of the support bricks (18') and on the adjacent end faces of the bricks (16), which are parallelogram-shaped in cross-section.

7. Partition according to any one of the claims 1 to 6, characterized in that the opening (12) formed in the wall (10) is defined by a mortar frame (20) poured on bricks (16, 16') placed on the periphery of said partition (14).

8. Partition according to claim 7, characterized in that the mortar frame (20) is replaced or completed, between the upper row of bricks (16, 16') and an upper horizontal post of the opening (12), by a packing (21) of unspun lead fibres.

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