FR2825728A1 - Method ensuring continuity in highway separation walls in which interruptions are made comprises positioning end pieces in which truss frames are housed, pouring concrete and placing cover above interruption between end pieces - Google Patents

Abstract

A prefabricated monobloc end piece (11) having a transverse end (12) and two lateral faces (13,14) is positioned and truss frames (7,8,20) are housed in the end piece internal volume. A removable formwork (25), which extends from the end piece to beyond the space where an end (6) of the small wall (1) is located, is then placed. Concrete (28) is poured into the formwork to bury the truss frames and the formwork is then withdrawn. The same operation is repeated to obtain a symmetrical wall (2) whose concrete is connected to that poured in an end piece (11') positioned at a distance (L) from the first end piece. A cover is placed above the interruption (3) which separates the two end pieces. An Independent claim is included for a highway separation structure.

Description

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 Method for ensuring the continuity of the protection provided by a low wall in which interruptions are practiced, abut for the implementation of this method and work obtained We know the danger of serious accidents caused by the traffic lanes of two-way vehicles opposite and we strive to obtain maximum security by building continuous longitudinal dividers to oppose the accidental crossing by a vehicle in distress of a central reservation on either side of which are the two tracks opposed.

These separators are often made up of a concrete wall of standardized shape and dimensions to offer maximum security.

It is understood that the physical separation of the two tracks can only be effective if it is continuous, while technical imperatives oblige to plan for interruptions of the wall.

This is the case when it is necessary to provide access hatches and manholes for underground installations, necessarily located in line with the low wall. These include fluid lines, electric cables, optical fibers and other buried conductors which must be accessible, especially when associated with junction, measurement and control devices regularly spaced along the traffic way.

Generally the interruptions of the wall are quite small and invariable opening, so that it is not very difficult to reconstruct the continuity of the protection by means of a robust removable cover, placed above the interruption and resting on the ends of the two low wall segments located opposite one another, on either side of the interruption.

In normal situation, the hood is in place and behaves as an effective protective element in the event that it is struck by a vehicle, so that the latter is retained in its normal lane, without being able to overcome the obstacle that constitutes the low wall. When it is necessary to access the underground installations, the cover is removed after securing the site, in particular by neutralizing the traffic lane closest to the low wall, all of this being well known in itself.

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But there are also problems which are much more difficult to deal with, in particular when the circumstances require the presence of a concrete low wall on engineering structures whose pavement is subject to significant longitudinal dimensional variation, due to the constraints. thermal which subject the work to expansion and contractions sometimes very important.

The project manager chooses the solution among several and it is then necessary to adapt to the chosen solution to realize the road superstructures, and in the first place the beacons, signboards, beams of protection and low walls .

By way of example, mention may be made of bridges and viaducts which are subjected to variations in dimensions of the order of lm50, which must be absorbed by means of expansion joints of different designs.

The most acute problem arises when it is a question of absorbing such variations in a single place because at present there is not known a satisfactory solution which makes it possible to accept such significant interruptions.

It should be remembered that the effective total dimensional variation due to contraction and expansion is called breath and that it requires a pavement joint whose footprint is much greater, so that the length of the wall interruption is not equal to the breath itself but to that required by the pavement joint.

To fix the ideas, we can specify that for a breath of lm40, the pavement joint occupies a length of 4m50, which is equal to the length of the break in the wall, that is to say the distance between the two low wall segments on either side of the interruption.

The presence of such an interruption is inadmissible and it is imperative to restore the continuity of the protection provided by the low wall.

The solution is known for breaths lower than Om40: it consists in placing above the interruption a generally metallic cover which rests on the ends of the two facing wall segments, cover which is fixed to one of the two segments of wall and which allows the relative displacement of these two segments by sliding on that to which it is not fixed.

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Continuity of protection means that a vehicle hitting the hood is retained on its track as if it had hit the concrete wall, which is why the hood must be particularly robust, which is easy to achieve for short lengths and what we do not know how to achieve for great lengths.

The present invention is a solution to this problem but also applies to short interruptions.

'on met en place un coffrage amovible qui s'étend depuis l'about jusqu'au delà de l'endroit où se situe une extrémité du muret soit déjà réalisée, soit à réaliser, 'on coule du béton à l'intérieur du coffrage en faisant en sorte qu'il noie les armatures, remplisse pratiquement tout le volume intérieur de l'about, et complète tout l'espace subsistant entre l'about et l'extrémité du muret, et en se liant au béton constitutif du muret, 'on retire le coffrage, 'et l'on répète les mêmes opérations que ci-dessus pour réaliser en opposition symétrique un muret dont le béton est lié à celui coulé dans un about positionné à une distance du précédent, To this end, the subject of the invention is a method for achieving the continuity of the protection provided to the users of a traffic lane by a structure for separating two opposite lanes, a structure which consists of a concrete wall, while providing interruptions of the wall itself, in particular to allow longitudinal dimensional variations, access to locations located directly above said wall and the like, of the type comprising a prefabricated cover placed on each interruption and capable of movement relative to the wall, characterized in that: 'a prefabricated monobloc abutment is positioned having a substantially transverse end and two lateral faces giving together at the end a general shape enveloping a hollow interior volume opening on the one hand to its upper part and on the other hand to the 'opposite from the transverse end,' one lodges in the interior volume of the end of the reinforcements which exceed clearly feels the face of the end opposite its transverse end,

'we put in place a removable formwork which extends from the end to beyond the place where one end of the wall is already made, or to be made,' we pour concrete inside the formwork by ensuring that it drowns the reinforcement, fills practically the entire interior volume of the end piece, and completes all the space remaining between the end piece and the end of the low wall, and by binding to the concrete constituting the low wall, 'we remove the formwork,' and we repeat the same operations as above to achieve in symmetrical opposition a low wall whose concrete is linked to that poured into a butt positioned at a distance from the previous one,

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 a cover is placed above the interruption which separates the two ends situated opposite, the length of which is greater than the distance which separates the ends of the two ends situated on either side of the interruption.

The invention also relates to an abutment intended to be fixed to a concrete wall, at a transverse end thereof which constitutes an edge of an interruption, characterized in that it is formed by a prefabricated hollow monobloc casing which has a substantially transverse face connected to two lateral faces which together give the casing the same profile as that of the low wall, this casing constituting a lost formwork for connecting concrete between itself and said low wall.

The invention also relates to a structure for separating two opposite lanes of vehicle traffic, which consists of a concrete wall having at least one interruption which determines two segments of low walls aligned and ending in two opposite transverse edges, characterized in that each interruption is limited by two ends situated opposite one another and each secured to one of the two segments of the wall which determine the interruption, each end being formed by a prefabricated monobloc casing connected to a concrete wall, and having side faces of the same profile as the wall, this structure further comprising a cover which is movable relative to the wall and which is arranged above the space separating the two ends extending up to 'at the low wall.

The invention will be better understood from the detailed description below made with reference to the accompanying drawing. Of course, the description and the drawing are given only by way of an indicative and nonlimiting example.

Figures 1 and 2 are schematic views in longitudinal section of a roadway comprising an expansion joint and provided with a protective wall having an interruption made in accordance with the invention.

Figure 3 is a schematic perspective view illustrating the method according to the invention for achieving the continuity of protection provided by a wall, despite an interruption thereof.

Figure 4 is a schematic cross-sectional view of a cover to cover the interruption made in accordance with the invention.

Figure 5 is a schematic perspective view of a butt according to the invention, according to a particular embodiment.

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Figure 6 is a schematic cross-sectional view of a cover to cooperate with the end of Figure 5 to cover the interruption made according to the invention.

FIG. 7 is a schematic view in longitudinal section showing the cover of FIG. 6 put in place and subject to the end piece of FIG. 5.

Referring to Figures 1 and 2, we see how the problem of absorbing longitudinal changes in a pavement due to the movements it undergoes as a result of changes in ambient temperature is presented, in particular on a structure. art such as a bridge or a viaduct.

As is known, a roadway subjected to such variations in length is cut transversely by a space E whose width t corresponds to the spacing of the two roadway segments A and B which border the space E.

The value of varies according to the temperature to which the work is brought due to the ambient temperature, the maximum spacing (Figure 1) between the edges of the space E constituting the breath.

To absorb variations in length while ensuring the continuity of the roadway for the vehicles using it, there is a so-called road joint assembly indicated by C, the length L also varies according to the temperature of the structure, and is always significantly greater than that of space E, whatever the instantaneous value of. As it is important not to interfere with the operation of the joint C, any longitudinal element integral with the roadway (including the wall separating the traffic lanes) must have an interruption at least equal to the length L maximum, clearly greater than the value of the breath..

In FIG. 1, the space E is at its maximum opening, the joint C being relaxed, while in FIG. 2, the space E is at its minimum opening, the joint C being compressed. It can thus be seen that the length: t on the one hand and the length L on the other hand vary between two extreme values represented respectively by FIGS. 1 and 2.

The invention makes it possible to produce a wall separating the opposite traffic lanes on a road of the type which has just been described.

Referring now to FIG. 3, we see how the wall is produced in two segments 1 and 2 separated by an interruption 3 measured between the two transverse faces which border the interruption 3.

As explained above, the length of the interrupt 3 is equal to L.

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 The location of the interruption 3 is fixed, considering that its edges 4 and 5 must be perpendicular to the transverse edges CI and C2 of the roadway which delimit the housing in which the roadway joint C is to be placed (Figures 1 and 2).

From the location provided for the edge 4, a distance D is determined below which the construction of the wall 1 is stopped, which, during the works, therefore has a transverse face 6 from which it is allowed to protrude, over a length a little less than the distance D, the reinforcements 7 and 8 usually provided one above the other, in the upper part of the wall 1.

Then, a factory prefabricated butt 11 is put in place, which is constituted by a robust monobloc and hollow casing, for example produced by welding of steel sheets.

The casing has one end formed by a flat transverse wall 12 called the front wall, to which are fixed two side walls 13 and 14 having the same profile as the sides of the wall 1.

The walls 13 and 14 are extended by vertical lower edges 15 and 16 similar to the sides of the foot of the wall, and each having here a housing 17 placed inside the profile of the casing and opening to the outside.

This casing determines an interior volume having the same shapes and the same dimensions as the wall 1 itself.

The casing does not have an upper wall or a rear wall, so that the interior volume is accessible from the outside from the top and from the rear.

In this interior volume, there are crosspieces which extend from one transverse wall 13 to the other 14 and which constitute spacers ensuring the rigidity and the undeformability of the casing during its handling and transport.

Here, there are shown two crosspieces 18 and 19 located in the upper part of the housing, one above the other, located opposite the front wall 12, near the open rear face of the housing, and positioned such that the reinforcements 7 and 8 which penetrate into the casing through this open rear face and extend to the immediate vicinity of the internal face of the front wall 12, can rest respectively on the cross member 18 and on the cross member 19.

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According to the invention, additional reinforcements are provided, here four in number arranged in a horizontal sheet 20, which are embedded in the concrete of the wall 1 over a certain length, of the order of one or two meters, so that they are firmly anchored there, their free ends extending beyond the transverse face 6 of the wall 1, in the same way as the upper reinforcements 7 and 8.

Two other cross members 21 and 22 are provided parallel to the upper cross members 18 and 19 but side by side and not one above the other, at a level coordinated with that of the reinforcements of the lower ply 20, so that these reinforcements can rest on these crosspieces 21 and 22, as far as the vicinity of the internal face of the front wall 12.

It is understood that the position of the housing is critical since its front wall 12 must have a precise location and that the reinforcements 7, 8 and 20 must not prevent the position of the housing from being adjusted exactly, so that the length of the reinforcements 7, 8 and 20 which exceeds the face 6 of the wall 1 must be well determined, either by positioning their free ends during the pouring of the concrete of the wall 1, or by cutting them later, on site, to the desired length during the placing work of the process according to the invention.

The position of the end piece is correct when the outside face of the front wall 12 coincides with the edges 4 and 5 of the interrupt 3 and the end piece can be fixed temporarily or definitively, by any desired means, for the immobilize.

A removable formwork 25 of the type known per se is then put in place, which must completely cover the space 26 which remains between the face 6 of the wall 1 and the open rear face of the casing, this formwork 25 being represented on the right side of Figure 3, for the finishing of the wall segment 2, but it is understood that the operations necessary for one of the segments are exactly symmetrical for the other, and therefore identical in the closest sense.

This formwork 25 will not be described in detail because it is within the reach of the skilled person, being simply indicated that it leaves an upper opening 27 through which one can access the space 26, as one can access the internal volume of the end piece 11 by its open upper face.

Through the upper opening of the casing and of the formwork 25, concrete 28 is then poured by any known means 29 and within the reach of those skilled in the art, to fill as completely as possible, in a single operation, all the space 26 and the entire interior volume of the end piece 11.

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Those skilled in the art know the methods and devices necessary to avoid air pockets and to perfectly fill the cavity determined by the formwork 25 and by the casing 11 (in particular by means of vibrators) by embedding the reinforcements 7, 8 and 20 .

When the concrete 28 is sufficiently dry to allow the formwork to be removed, the formwork 25 is removed but the casing 11 which definitively constitutes a lost formwork is left in place.

To ensure a perfect anchoring to the wall segment 1 in order to achieve a coherent and robust whole, it is necessary to obtain a good cohesion of the concrete of this segment 1 and of the concrete 28, and for this purpose, it is good to proceed to the finishing of the structure at a time when the concrete of segment 1 is not yet completely dry, so that the concrete 28 intimately allies with it.

The continuity of the low wall 1 is thus obtained without defect from its origin to the internal face of the front wall 12, inside the end 11.

By proceeding as described above, there is an end of a wall which borders the interruption 3.

To achieve the opposite end, we proceed in exactly the same way symmetrically, in opposition, and therefore we will not repeat the description of operations.

We have described the realization of the first end by assuming that the first segment 1 of the low wall was already built and we can proceed in the same way for segment 2, that is to say that we can build the low wall on either side of the interruption 3 and subsequently make the two ends 11 and 11 opposite, as soon as the location of the faces 6 and 6 ′ has been determined and left on standby the reinforcements 7,8 and 20 over a sufficient length beyond and below the two faces 6 and 6 ′ of the wall segments 1 and 2. The method of the invention therefore does not slow down the progress of the construction site of the wall.

But we understand that we can, depending on the circumstances and the requirements of the site, start the opposite end before making the segment 2 of the wall, in which case we pour the concrete 28 during the same operation as that of the concrete segment 2 then we continue this segment according to the usual methods.

The elements of segment 2 which are identical, but symmetrical, to those of segment 1 have the same references assigned the sign ['].

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When the two sides of the interrupt 3 are finished, a cover 30 is placed above it, the length f of which is greater than the largest value of L, so that even in the situation of the greatest possible spacing between the two ends opposite the interruption 3, the cover 30 rests on the two ends 11 and 11 'without any attachment to one or the other, so that relative movements between the fixed ends 11 and 11 'on the one hand and the cover 30 on the other hand, that is to say that the dimensional modifications of the wall can occur independently of the cover 30 which remains in place.

This cover 30 must be robust enough to oppose to the vehicles which accidentally strike it a resistance at least equivalent to that of the wall itself. In addition, it must be solidly not fixed but subject to the wall to absorb violent shocks without moving and, above all, without being lifted.

The cover 30 of Figure 4 is shown in a single piece of steel, either by stamping a sheet, or by welding separate elements.

Its internal face has the same profile as the ends 11 and 11 ′, and therefore also the same as the low wall, in order to avoid any discontinuity in shape throughout the structure.

The cover 30 is formed by a narrow upper face 31 to which two flanks 32 and 33 are connected, ending in the lower part by two vertical strips 34 and 35 When the cover 30 is in place it rests by the ends of its internal upper face 31 on the concrete 28 flush with the top of the casings and on the upper edges of the front wall 12 and of the side walls 13 and 14 thereof, along a length at most equal to that of the casings.

If one wishes to avoid the contact of the metal cover 30 and the concrete 28 which is very abrasive, one can place a metal soleplate (not shown) at the top of the casing after pouring the concrete 28, so that the internal upper face 31 rests on this sole, which achieves less aggressive metal-to-metal contact.

The sides 32 and 33 of the cover 30 are in the immediate vicinity of the side walls 13 and 14, without appreciable friction, and its vertical bands 34 and 35 are placed opposite the lower edges
15 and 16.

As described above, these edges 15 and 16 have housings 17 and about halfway up these, the vertical bands 34 and 35 are crossed with holes (not visible in the drawing).

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The cover 30 is placed but it is made so that it leaves the housings 17 accessible on one side of the interruption 3 and is introduced into these housings 17 which are free from the retaining pieces 36, then the cover 30 is moved to that it unmasks the housings 17 on the other side of the interruption in order to introduce the corresponding retaining pieces 36, then when the cover 30 is in the final position, the pieces 36 are subjected to the vertical strips 34 and 35 by means fasteners of any known type 37 (Figures 1,2 and 3).

Thus, the cover 30 is subject to the ends 11 and 11 ′ with respect to which it can slide longitudinally because it remains practically immobile when the ends approach or move away from one another according to the longitudinal dimensional variations of the structure. , but it cannot be lifted under the effect of a very violent impact, even from an accidented vehicle because the parts 36 hold it in place, being in abutment against the upper face of the housings 17.

We thus achieved the continuity of the wall despite its interruption 3, and traffic safety is ensured.

Referring now to Figures 5 and 6, we see a particular embodiment of the housing and the cover.

The casing is shown in perspective, from the front, in order to clearly show the different elements that compose it. It is therefore in the position of segment 2 of FIG. 3, but for the sake of simplicity, references which do not include a ['] are used.

The front face 12 is in the plane of the side 5 of the interruption because this side serves as a basis for positioning the casing, as explained above. This face 12 is therefore qualified here as the main face in view of its importance and not because of its surface area, and it is by reference to it that the other elements which we will now describe are located.

Beyond the main face 12, that is to say in front of it, is a prominent spout 41 extending to a transverse support 42 resting on the ground by two lateral supports 43 having extensions 44 indented to leave a transverse lower space 45.

The lateral faces 13 and 14 are notched in the same way and each have a vertical edge 46 which continues the extension 44, so that the transverse lower space 45 extends longitudinally to a rim 47 also transverse, located clearly in below the main face 12.

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There is thus a space 45 much longer than those which are usually provided for existing concrete abutments, that is to say 30cm at most. If this value is retained with the example of FIG. 5, this space 45 extends over approximately 60 cm and the utility of this space 45 is explained below.

Above the spout 41, overhanging, and therefore beyond the main wall 12, there is a support 48 for a horizontal profile 49 which extends from a small transverse face 50 situated below the main face 12, up to the free end 51 of the support 48.

The other elements of the casing not visible in this FIG. 5, are identical to those which have been described with regard to FIG. 3, in particular the open rear face and the internal crosspieces.

The casing which has just been described is implemented as explained above with regard to its positioning and its connection with the wall segment of which it must constitute the end: concrete reinforcements, formwork , casting, formwork.

When the two abutments facing the same interruption are finished, a cover 60 is placed which is shown in section in FIG. 6.

This cover 60 is formed by the assembly on site of two lateral shells 61 and 62 each comprising a side 63-64, a horizontal upper edge 65-66 and a vertical lower edge 67-68.

In the upper part, the shells 61 and 62 include a longitudinal reinforcing angle 69-70 serving as support for bolts and nuts 71 situated opposite the lateral access passages 72 and serving to fix the two shells 61 and 62.

The bolts and nuts 71 serve as an axis for a rolling member, shown here in the form of a roller 73, mounted idly and to be used to support the cover 60 when after the latter has been put in place, the roller 73 will be placed on the profile 49 serving as longitudinal support on the casing.

In the lower part, the shells 61 and 62 comprise a longitudinal reinforcement angle 74-75 serving as support for threaded rods and nuts 75 located opposite lateral access passages 76 formed in the vertical edges 67 and 68, these rods and nuts 75 serve to fix the two shells 61 and 62 to each other.

After fitting the shells 61 and 62 on either side of the casing, the bolts and nuts 71 are tightened by the access passages 72, then engages the threaded rods 75 in the lateral passages 76 so that they 'extend into the lateral space 45 which serves as a passage for joining the two shells 61 and 62 in the lower part.

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Thus, the cover 60 if it is requested to be lifted following an impact from a vehicle, is retained in position by virtue of the threaded rods and nuts 75 which abut under the vertical parts 44 and 46.

The length of the space 45 is sufficient to allow the longitudinal deflections of the rods and nuts 75 when the butts approach and move apart following the longitudinal dimensional variations of the wall.

The ends are formed from prefabricated monobloc casings, in particular made of metal, and therefore have precise dimensions, the lost formwork which they constitute guaranteeing a mechanical precision of higher quality than that coming from concrete ends.

As a result, the covers can themselves be manufactured with rigorous dimensions, so that the cooperation of the covers and the ends is done mechanically, with more precision than with current masonry structures.

The incessant movements of the structure, when its longitudinal dimensions are subjected to the effects of expansion and contraction, cause significant friction between the elements in relative movement, namely the ends on the one hand and the cover on the other.

The use of galvanized steel for the housings and for the cover which are in contact with each other is therefore not recommended since this friction would have the effect of causing significant wear on the surface and premature destruction of the coating. zinc.

This is why the description above recommends stainless steel whose price is higher than galvanized steel but whose qualities are not degraded by friction and which therefore does not involve maintenance and maintenance.

We could also make the ends by molding or forming in synthetic material, the important thing being to prefabricate the casings in the factory by means providing good accuracy of dimensions and shapes.

The foregoing description refers to low-lying walls, but it goes without saying that the invention also applies to more restricted interruptions than those to which reference has been made, namely those which extend over longer distances. 'one meter. Currently,

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 current standards refer to puffs of 40cm maximum, and we see that if the invention allows to largely exceed this limit, it also allows to produce industrially easy ends to install for smaller puffs.

circulation : regards, trappes d'accès à des conduites enterrées, socles, etc. It will be recalled that the invention also applies to interruptions which are not linked to dimensional variations, but essentially to practical necessities when it is necessary to be able to access an element located at the location of the track separating wall.

circulation: manholes, hatches for access to buried pipes, bases, etc.

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Claims (16)

 'and the same operations are repeated as above to produce in symmetrical opposition a low wall (2) whose concrete is linked to that (28) poured into a butt (11') positioned at a distance (L) from the previous one (11), 'we place above the interruption (3) which separates the two ends (11 and 11') located opposite, a cover (30-60) whose length (. = / Is greater than the distance (L) which separates the ends (4 and 5) of the two ends (11 and 11 ') located on either side of the interruption (3).

CLAIMS 1. Method for achieving the continuity of the protection provided to users of a traffic lane by a work of separation of two opposite lanes, work which consists of a concrete wall, while providing for interruptions of the wall itself, in particular to allow longitudinal dimensional variations, access to locations located directly above said low wall and the like, of the type comprising a prefabricated cover placed on each interruption and capable of movement relative to the low wall, characterized in that: prefabricated monobloc butt (11) having a substantially transverse end (12) and two lateral faces (13 and 14) giving together at the end a general shape enveloping a hollow interior volume opening on the one hand at its upper part and on the other opposite the transverse end, 'it is housed in the interior volume of the end of the frames (7-8-20) which clearly protrude from the face of the end piece (11) opposite its transverse end (12), a removable formwork (25) is put in place which extends from the end piece (11) to beyond the place where one end (6) of the wall (1) is located, either already made or to be made, * concrete (28) is poured inside the formwork (25) making it drown the reinforcements (7 -8-20), fills practically the entire interior volume of the end piece (11), and completes all the space (26) remaining between the end piece (11) and the end (6) of the wall (1), and by binding to the concrete constituting the wall (1), 'the formwork (25) is removed, <Desc / Clms Page number 15> 2. Method according to claim 1, characterized in that: 'the wall (1) is first produced, on one side of the desired interruption (3), by pouring concrete to a face (6) situated at a certain distance (D) below the location of the end (4) desired for the interruption (3), leaving reinforcements (7-8-20) protruding from said face (6), 'we position a butt (11) so that its transverse end (12) is located at the edge (4) desired for the interruption (3),' we determine the position of the ends of the frames (7-8-20) , optionally by cutting them off, so that they extend close to the internal face of the transverse end (12) of the end piece (11). 3. Method according to claim 2, characterized in that the concrete is poured (28) into the end piece (11) and up to the face (6) of the wall already made, before the concrete of said wall is fully dry, so that the concrete (28) poured last intimately combines with that poured first.

4. Method according to claim 1, characterized in that: 'first positioning a butt (11), there are housings (7-8-20), one end of which is close to the internal face of the 'transverse end (12) of the end piece (11),' a removable formwork (25) is put in place which extends from the end piece (11) to beyond the place where one end is located ( 6) of the wall (1) to be made, 'concrete is poured (28) inside the formwork (25) making it drown the reinforcements (7-8-20), fills practically all the volume inside the end (11), and constitutes the beginning of a segment (1) of the low wall.  'and we continue building the low wall. 5. Method according to claim 1, characterized in that there is a frame (20) which extends horizontally to the lower part of the wall and the interior volume at the end (11). 6. Method according to claim 1, characterized in that there is a sole on the concrete (28) after it has been poured, so that the cover (30) rests on this sole and not on the concrete ( 28). <Desc / Clms Page number 16>  7. Structure for separating two opposite traffic lanes, comprising an abutment intended to be fixed to a concrete wall constituting said structure, at a transverse end thereof which constitutes an edge of an interruption, characterized in that it is formed by a prefabricated hollow monobloc casing which has a substantially transverse face (12) connected to two lateral faces (13 and 14) which together give the casing the same profile as that of the wall (1), this casing constituting a lost formwork for connecting concrete (28) between itself and said low wall (1). 8. A structure according to claim 7, characterized in that the casing has a main face (12) transverse to the common axis of the wall (1) and the end piece (11), and in front of which is a spout prominent (41) which must rest on the ground by a transverse end support (42-43), a lower space (45) which crosses the end piece (11) right through transversely to it being thus determined and s' extending longitudinally to a rim (47) which is itself transverse and which is clearly below the main face (12). 9. A structure according to claim 7, characterized in that the casing has lower housings (17) for retaining members (36) integral with a cover (30) which must be placed at least partially above two ends (11 and 11 ') located opposite one another, on either side of an interruption (3) and thus covering said interruption (3), these members (36) having to be placed in the housings lower (17). 10. The structure as claimed in claim 7, characterized in that the casing has a flat horizontal longitudinal support (49) for at least one rolling member (73) rotatably mounted on a cover (60) which must be placed at least partially at- above two butts (11 and 11 ') located opposite one another, on either side of an interruption (3) and thus covering said interruption (3). 11. A structure according to claim 10, characterized in that the longitudinal support (49) extends to the upper part of the casing, from a small transverse face (50) located below the main face (12) up to at a free end (51) located beyond said main face (12). 12. A structure according to claim 7, characterized in that the two lateral faces (13 and 14) of the casing are joined by at least one internal crosspiece (18-19-21-22) situated opposite the transverse face ( 12). <Desc / Clms Page number 17> 13. A structure according to claim 12, characterized in that the casing has two crosspieces (18 and 19) which are located in its upper part, one (18) above the other (19), and the upper face of each is located at a level corresponding to the lower face of a longitudinal concrete reinforcement (7-8), one free end of which must extend inside said hollow body during its installation on site. 14. The structure as claimed in claim 12, characterized in that the casing has at least one cross member (21-22) situated in its lower part and the upper face of which is located at a level corresponding to the lower face of a concrete reinforcement. longitudinal (20) of which a free end must extend inside said hollow body during its installation on site. 15. The structure as claimed in claim 7, characterized in that the casing has an upper longitudinal opening. 16. The structure as claimed in claim 7, which consists of a concrete wall having at least one interruption which determines two aligned wall segments ending in two opposite transverse edges, characterized in that each interruption (3) is limited by two butts (11 and 11 ') located opposite one another and each secured to one of the two segments (1 and 2) of the wall which determine the interruption (3), each about (11-11' ) being formed by a prefabricated monobloc casing connected to a concrete wall (1-2), and having lateral faces (13 and 14-63 and 64) of the same profile as the wall (1-2), this work comprising in in addition to a cover (30-60) which is movable relative to the wall (1-2) and which is arranged above

 of space separating the two ends (11 and 11 ') extending to the wall (1-2). ***