EP0979332B1 - Method for making prefabricated structural elements, and prestressed structure produced with said elements - Google Patents

Abstract

A process of manufacturing concrete construction elements is provided. A first sheath is placed in a first mold, the first sheath connected at an end to a first sleeve applied against a wall of the mold, the sleeve engaging a positioning boss placed on the wall. Concrete is poured into the first mold and set to obtain the first element. The first element is extracted from the first mold and includes a contact face shaped by the wall. A second sheath is placed in a second mold, the second mold having one side formed by the contact face. The second sheath includes an end connected to a second sleeve held in position relative to the first sleeve by a positioning joint. Concrete is poured into the second mold and set to obtain a second element. The second element is extracted from the second mold by disengaging the positioning joint.

Description

The present invention relates to the construction of prestressed structures from elements in prefabricated concrete conjugates.

The invention applies in particular, but not exclusively for cantilever bridges with prefabricated segments with conjugate joints (see for example the article: "Evolution and recent developments of prefabricated segment bridges "de Jacques Mathivat, Annals of the Technical Institute of Building and Public Works, Supplement to No. 342, September 1976, pages 21-32, or the request for Patent E-P-A-0 462 350).

In this technique, the successively assembled elements (segments) of the bridge are produced one after the other, the front face of the element n serving to delimit the rear side of the mold for manufacturing the element n + 1. This guarantees the conjugation of the adjacent faces of the elements to be assembled. These faces are glued to each other during the installation of the element n + 1 on the site. Complementary reliefs are usually provided on these faces to facilitate their mutual positioning and to help support the element n + 1 before its final fixing.

These works are frequently subject to longitudinal prestressing using cables prestressed threaded in sheaths embedded in concrete of several successive elements.

The realization of this prestress is a delicate operation.

The positioning of the sheath sections in the elements must be very precise so that the cables of prestress can be threaded without difficulty.

The most difficult is to guarantee the watertightness of the sheath at the interfaces between elements. This sealing is necessary to ensure the sustainability of the prestress subject to the risk of infiltration of the law of the joint between the elements. The joint can be made according to two methods: "dry joint" when the faces of concrete come juxtaposed without interface product; or "glued joint" when an interface adhesive is placed on the joint right. In this second case, the sealing responds by in addition to the need to prevent epoxy glue or analog arranged between the elements can penetrate into sheaths and hinder the introduction of cables. Else apart, the sheaths are usually injected with a filler (cement grout, grease wax, resin ...) used in particular to protect cables against corrosion. This product must not escape outside sheath during injection.

Certain areas of the structure may have a fairly high density of sheaths, and we don't have the assurance that the epoxy glue will seal between these ducts. This results in the serious risk that grout injected under pressure into a sheath comes to infiltrate in one or more neighboring ducts, where the injection then becomes very difficult if not impossible.

In general, pneumatic tests are carried out to ensure the tightness of the prestressing ducts before installing the cables and injecting the grout. Yes leaks are detected between certain ducts, we are led to very carefully inject the grout so as to try to have a single grout advancement front in these different sheaths. This results in procedures extremely complicated and difficult to inject control.

The solutions consisting in interposing O-rings around the sheaths between the mating faces of the elements are not reliable in terms of sealing, these seals being able to be displaced during the positioning of the element n + 1 .

Patent application FR-A-2,596,439 describes a connecting device between sheath sections of prestressed, comprising an engaged cylindrical sleeve between the mouths of two contiguous sections for ensure the continuity of the sheath, and an elastic seal surrounding the cylindrical sleeve to realize sealing and compensating for irregularities in positioning of the blocks and their dimensional deviations.

It has also been proposed to introduce a sheath pleated longitudinally in the sheath after gluing, this sleeve being brought to the right of the contact surfaces previously assembled and then expanded using a pneumatic device to be glued to the internal wall of the sheath using an adhesive placed at the bottom of the folds. This method is very complex to implement, moreover impossible when the sheaths are not rectilinear. Furthermore, it does not prevent glue infiltration into the sheath during assembly elements.

An object of the present invention is to provide a simple and effective solution to the problems encountered to carry out the prestressing of structures built at from prefabricated elements combined.

• disposer dans un moule au moins un premier tronçon de gaine de précontrainte ayant une extrémité raccordée à un premier manchon appliqué contre une paroi du moule, le premier manchon présentant une forme intérieure venant en prise sur un plot de positionnement disposé sur ladite paroi;
• couler du béton dans ledit moule de manière à obtenir le premier élément après prise du béton;
• extraire du moule le premier élément, dont une face de contact a été mise en forme par ladite paroi;
• constituer un second moule dont un côté est formé par ladite face de contact du premier élément;
• disposer dans le second moule au moins un second tronçon de gaine de précontrainte ayant une extrémité raccordée à un second manchon maintenu en position par rapport au premier manchon au moyen d'un raccord de positionnement retenu élastiquement dans l'un au moins des premier et second manchons;
• couler du béton dans le second moule de manière à obtenir le second élément après prise du béton; et
• extraire le second élément du second moule, en désengageant le raccord de positionnement de l'un au moins des premier et second manchons.

The invention thus provides a method of manufacturing concrete building elements comprising at least a first and a second conjugate elements. This process includes the following steps:

• placing in a mold at least a first section of prestressing sheath having an end connected to a first sleeve applied against a wall of the mold, the first sleeve having an internal shape engaging on a positioning stud disposed on said wall;
• pouring concrete into said mold so as to obtain the first element after setting of the concrete;
• extracting from the mold the first element, one contact face of which has been shaped by said wall;
• constitute a second mold, one side of which is formed by said contact face of the first element;
• placing in the second mold at least a second section of prestressing sheath having one end connected to a second sleeve maintained in position relative to the first sleeve by means of a positioning connector retained elastically in at least one of the first and second sleeves;
• pouring concrete into the second mold so as to obtain the second element after setting of the concrete; and
• extract the second element from the second mold, disengaging the positioning fitting from at least one of the first and second sleeves.

The positioning fitting can be the same piece that the fitting that will seal between the sleeves after the final assembly of the elements. In in this case, you can leave the fitting in place in one or the other of the two sleeves during the storage of elements.

The sleeves and fitting provide precise and correct positioning of each section of sheath in each element, as well as the correct alignment of successive sections. Dimensional deviations to compensate are thus minimized.

During the assembly of two consecutive elements, the sealing fittings, which are fitted with the sleeves ending the sheath sections on the face of one of the elements, engage in the sleeves ending the corresponding sheath sections of the other element. This engagement realizes the sheath tightness vis-à-vis the glue, one of the complementary faces of which is generally coated. It also ensures the absence of communication with the outside or between neighboring ducts when injecting cement grout or other product filling in the ducts.

The sealing connection can be a single piece with one of the two sleeves. But it is preferably removably attached to one of the two sleeves, for example by screwing or interlocking elastic.

• le plot de positionnement peut être pourvu de moyens d'accrochage élastique qui coopèrent avec une gorge annulaire que présente la forme intérieure du premier manchon pour le maintenir de manière amovible dans le moule ;
• le manchon dans lequel le raccord de positionnement est retenu élastiquement peut présenter une ouverture angulaire d'au moins 30 degrés ;
• le raccord de positionnement peut être retenu élastiquement dans chacun des premier et second manchons ;
• le raccord de positionnement peut être vissé dans l'un des premier et second manchons ;
• lorsqu'une caractéristique selon l'un des deux alinéas précédents est prévue, le raccord de positionnement peut être traversé par un orifice coaxial aux manchons, de section au moins égale à la section intérieure des premier et second tronçons de gaine, et dans ce cas on laisse en place le raccord de positionnement dans le premier ou le second manchon après l'extraction du second élément.

In preferred embodiments, the method of manufacturing concrete building elements according to the invention has one or the other of the following characteristics;

• the positioning stud may be provided with elastic hooking means which cooperate with an annular groove which has the internal shape of the first sleeve to hold it removably in the mold;
• the sleeve in which the positioning connector is elastically retained may have an angular opening of at least 30 degrees;
• the positioning connector can be retained elastically in each of the first and second sleeves;
• the positioning connector can be screwed into one of the first and second sleeves;
• when a feature according to one of the two preceding paragraphs is provided, the positioning connector can be crossed by an orifice coaxial with the sleeves, of section at least equal to the internal section of the first and second sheath sections, and in this case the positioning fitting is left in place in the first or second sleeve after the extraction of the second element.

The invention also relates to a work of construction, comprising an assembly of elements prefabricated with a series of elements as defined above, the contact faces of the conjugate elements being applied against each other so that the sheath sections are arranged in the extension the from each other to form complete sheaths, with fittings engaged in the sleeves to connect so waterproof the adjacent sheath sections, and in which prestressing cables and a filler occupy the interior of the sheaths.

• la figure 1 est une vue en perspective d'un voussoir préfabriqué auquel peut être appliquée la présente invention ;
• la figure 1A est une vue latérale partielle illustrant l'assemblage de deux voussoirs consécutifs ;
• la figure 2 est une vue en coupe illustrant la mise en place d'un tronçon de gaine dans un moule de fabrication d'un premier élément ;
• la figure 3 est une vue en coupe partielle du premier élément fabriqué ;
• la figure 4 est une vue en coupe illustrant la mise en place d'un second tronçon de gaine dans un moule de fabrication d'un second élément ;
• la figure 5 est une vue en coupe partielle du second élément fabriqué ;
• la figure 6 est une vue en coupe montrant deux variantes de réalisation des moyens de jonction de deux tronçons de gaine de précontrainte ; et
• la figure 7 est une vue en coupe montrant une autre variante de réalisation de ces moyens.

Other particularities and advantages of the present invention will appear in the description below of nonlimiting exemplary embodiments, with reference to the appended drawings, in which:

• Figure 1 is a perspective view of a prefabricated segment to which the present invention can be applied;
• FIG. 1A is a partial side view illustrating the assembly of two consecutive segments;
• Figure 2 is a sectional view illustrating the establishment of a sheath section in a mold for manufacturing a first element;
• Figure 3 is a partial sectional view of the first manufactured element;
• Figure 4 is a sectional view illustrating the establishment of a second sheath section in a mold for manufacturing a second element;
• Figure 5 is a partial sectional view of the second manufactured element;
• Figure 6 is a sectional view showing two alternative embodiments of the means for joining two sections of prestressing sheath; and
• Figure 7 is a sectional view showing another alternative embodiment of these means.

The invention is described below in its application to bridges with prefabricated segments with joints conjugates.

Such a segment 1 is shown in FIG. 1. Element 1 has the general shape of a delimited box internally by a base 2, laterally by two walls 3 inclined symmetrically, and above by an apron 4 extended laterally beyond the walls 3 to set the width of the bridge.

In the longitudinal direction, element 1 is delimited by a rear face 6 and a front face 7 substantially parallel. The rear face 6 is intended for come into contact against the front face, in shape complementary, of the previous element installed on the structure under construction (in the case of the first element installed on a bridge pier, the front complementary belongs to this stack). Likewise, the face front 7 of element 1 is intended to receive the face back of the next item to be put in place.

The contact faces of complementary shapes of the adjacent elements are provided with reliefs 8 a , 8 b ensuring good relative positioning of the elements when they are brought together. In the particular example shown in Figures 1 and 1A, these reliefs are situated on the side walls of the end faces 3 of the elements, and have the shape of a part of trapezoidal profile bosses 8 has made during the molding on the front face 7 a of the element 1 a , and on the other hand recesses with a complementary trapezoidal profile 8.8 b produced during molding on the rear face 6.6 b of the element 1, 1 b .

When an assembly adhesive is used, it is for example an epoxy resin with which one or the other of the two complementary faces is coated before assembly. After its installation, the element 1.1 b is clamped against the previous element la, so that the recesses 8.8 b with trapezoidal profile formed on its rear face 6.6 b provide support on the complementary bosses 8 a of the front face 7 a of the preceding element 1 a to support it before the setting of the glue. After setting the glue, the reliefs at least partially take up the shearing force exerted at the joint by the load of the work

Element 1 has a number of sections of longitudinal sheath 10, intended to receive cables prestressing. These cables are anchored on the structure to their ends by means of anchoring devices appropriate. Some of these anchors 11 can optionally be arranged on bosses 12 provided inside the box shape of the element. The sheath sections 10 open onto the rear face 6. and / or on the front face 7 of the element. He imports ensure the continuity and tightness of each sheath prestressing at the level of the faces in contact with the elements adjacent. For this, use is made, according to the invention, of connecting pieces (sleeves and fittings) which are described below.

After positioning the element, it is tightened against the previous item, at least until assembly glue. This tightening can be done in installing certain prestressing cables if rear-facing anchors 11 are provided on the element. Otherwise, or in addition, external actuators are used to tighten the elements against each other.

Once the successive sections of a sheath have been assembled, we check the tightness of this sheath using a pneumatic device. We can then thread the strands of the prestressing cable into the sheath, tension them, anchor them to their ends, then inject a filling product such as a cement grout in the sheath to fill the and protect the cables against corrosion.

The successive elements 1 are prefabricated in molded concrete. Figures 2 to 5 illustrate the prefabrication of two consecutive elements 1 a , 1 b .

To make the first element, we use a mold having the required shape. On the front side of the element, the mold is delimited by a metal wall 15 (Figure 2) of generally planar shape, having additional recesses of the bosses 8a at the locations prescribed.

Positioning pads 16 are fixed on the inside of the wall 15, for example by welding. These studs 16, of generally cylindrical shape, are used to install the sheath sections 10 a of the first element 1 a in the mold.

The front end of each sheath section 10 a is engaged in a sleeve 18a to an inner stopper 19 is provided in the sleeve. The seal between the sheath section 10 a and the sleeve 18 a is produced in a conventional manner using a heat-shrinkable sheath or an adhesive tape 20.

The sleeve 18 a is in a sufficiently rigid material so as not to deform when the concrete is poured into the mold, for example a plastic such as high density polyethylene.

Beyond the stop 19 a , the sleeve 18 a has an enlarged portion 21 a of suitable shape to come into engagement on the positioning pad 16. The sleeve 18 has connected to the sheath section 10 a is engaged on the pad 16 by an operator. The sleeve 18 a is thus positioned accurately against the wall 15 of the mold and retained in this position by the latching means provided on the positioning boss 16. These means may comprise an elastic member 22 housed in an annular groove 23 provided outside the cylindrical shape of the positioning pad 16, and cooperating with another annular groove 24 a provided in the interior shape of the enlarged portion 21 a of the sleeve 18 a . The member 22 consists for example of an O-ring spring with flat turns which can be crushed when it is compressed radially.

Once the various sheath portions 10a of the element 1a have been installed in this way, the concrete is poured into the mold. After setting, the element 1 a can be extracted from the mold, the wall 15 being removed by tearing off the positioning pads 16 from the sleeves 18 a . This wall 15 releases the front face 7a of the element. The front end 25 a of the sleeve 18 a , which was applied against the wall 15, lies in the plane of the front face 7 a . The constitution of the element la in the vicinity of the front end of a section of sheath 10 a is shown in FIG. 3.

The front face 7a of the element 1 is used to define the rear side of the manufacturing mold of the next element 1b (figure 4).

For mounting the sheath sections 10 b of the element 1 b , a positioning connector 30 is engaged in the enlarged portion 21 a of each sleeve 18 a appearing on the front face 7 a of the first element 1 a .

This connection 30 can be made of a more flexible material than the sleeve 18 a , for example of a low density polyethylene having a modulus of elasticity of the order of 500 N / mm ² .

A rear portion of connector 30 has an outer shape corresponding to the inner shape of the widened portion 21a of the sleeve 18a, with in particular an annular bead 31 complementary to the annular groove 24a of the sleeve 18 a. This rear portion of the connector 30 is pushed into the widened portion 21a of the sleeve 18a, where it is held in place by the cooperation of the bead 31 with the annular groove 24 a.

The other (front) part of the connector 30 protrudes beyond the front face 7a of the element 1 a. This front part may have an outer contour of generally frustoconical shape provided with another annular bead 32. Preferably, this frustoconical shape, which converges away from the element, has a half-angle at the top β less than l angle  formed by the flanks of the trapezoidal profile of reliefs 8a, 8b with the direction perpendicular to the end surfaces 7a, 6b, which ensures that the portion 30 is not damaged during handling of the item 1 b .

Each sheath section 10 b of the second element 1 b is engaged in another sleeve 18 b up to an internal stop 19 b , with a heat-shrinkable sheath or an adhesive tape 20 to ensure the seal between the sheath and the sleeve. Opposite the sheath section 10 b , the sleeve 18 b has an enlarged portion 21 b whose internal shape is complementary to the external shape of the projecting front part of the positioning connector 30. In particular, this enlarged portion 21 b has an internal annular groove 24 b which cooperates with the annular bead 32 of the positioning connector to hold the sleeve 18 b in place against the sleeve 18 a in the mold for manufacturing the second element (FIG. 4).

Once all the sheath sections 10b of the second element have been put into place in the mold using the fittings 30 and the sleeves 18b , concrete is poured into this mold to make the second element. After setting the concrete and extracting the mold, by tearing off the fittings 30 out of the enlarged portions 21 b of the sleeves 18 b , the second element 1 b has the configuration shown in FIG. 5 in the vicinity of the rear end of the sheath section 10 b , the sleeve 18 b having its rear end 25 b in the plane of the rear face 6 b of the element.

The fact that the positioning connector 30 remains in place on the first element 1 a rather than on the second element 1 b results from the angular opening of the enlarged portion 21 b of the sleeve 18 b , which is larger than the opening angle of the enlarged portion 21a of the other sleeve 18 a.

The positioning fitting 30 remaining on the first element will serve as a sealing connection between the corresponding sheath sections 10 a , 10 b during the assembly of the elements on the site. This connector 30 is thus provided with an orifice coaxial with the sheath sections 10 a , 10 b , the section of which is preferably at least equal to the interior section of these sheath sections. Due to its complementary external shape of the housing defined between the enlarged portions 21 a , 21 b of the sleeves, the relative elasticity of its material and its constant and relatively small thickness, the connector 30 undergoes a certain radial compression which ensures the sealing of the sheath at the interface between the elements 1 a , 1 b .

The angular opening of the widened portion 21b of the sleeve 18 b which substantially corresponds to the angle 2β top of the frusto-conical front portion of the connector 30 is preferably greater than 30 degrees. With this arrangement, the connector 30 can readily penetrate into its housing when the second element 1b is closer to the first element 1a.

If the projecting front part of the connector 30 is damaged during the storage of the elements, this connector 30 can be torn off from the sleeve 18 a in which it is retained elastically, and replaced by another connector.

Alternatively, the positioning patch 30 used during the prefabrication of the elements 1 a, 1 b may be separate from the sealing connector installed for the final assembly of the elements, provided that the connector 30 correctly positions the sleeve 18b in the mold of manufacturing the second element.

In another alternative embodiment, the positioning and sealing connection could be in one piece with one of the two sleeves. For example, the first element could be manufactured in the manner illustrated with reference to Figures 2 and 3 (but preferably with sleeves 18 a whose enlarged portion 21 a would have a greater angular opening), and the second sleeves connected to the ends rear of the sheath sections 10 b could be extended by a more flexible rear part whose external contour would be complementary to the internal shape of the enlarged portion 21 a . To make this rear part more flexible, its thickness can be reduced compared to the rest of the sleeve, and / or make this sleeve from two materials having different elastic moduli. With such an embodiment, the number of parts required to make the seal is minimized.

In other variants (FIG. 6), the connection of positioning and / or sealing is screwed into one or the other of the two sleeves.

In the embodiment illustrated in FIG. 6, the positioning and sealing connector 50 has a cylindrical rear part engaged in the sleeve 38 a to which the sheath section 10 a of the first element is connected, and a frustoconical front part provided of an outer annular bead 52. Between these two parts, the connector 50 has a transverse shoulder 54 which abuts against the front end 45 a of the sleeve 38 a and against the front face of the first element. The cylindrical part of the connector 50 is provided with a female thread 53 complementary to a male thread 46 a provided inside the sleeve 18 a . Thus, the connector 50 can be screwed into the first sleeve 38 a , the threads contributing to the seal.

In the frustoconical part of the connector 50, the seal results from the engagement of the bead 52 in the groove 44 b provided inside the enlarged portion 41 b of the second sleeve 38 b .

In the example shown in the lower part of FIG. 6, the seal is further reinforced by the fact that the two ends of the connector 50 have thinned lips 55 a , 55 b which flex elastically inwards when the connector 50 is installed in sleeves 38 a , 38 b . This sag can be caused by curved internal surfaces provided in the sleeves 38 a , 38 b , on the back of the stops 39 a , 39 b respectively receiving the ends of the sheath sections.

In the alternative embodiment shown in the upper part of FIG. 6, an annular housing 47 a , 47 b , open towards the front side, is provided in the internal shape of the sleeve 38 a , 38 b , on the back of the stop 39 a , 39 b . The two ends of the positioning and sealing fitting then compress flat seals 48 a , 48 b placed in the housings 47 a , 47 b .

• une partie cylindrique 59 pour recevoir l'extrémité des tronçons de gaine 10a, 10b ;
• un épaulement intérieur 60 à l'extrémité de la portion cylindrique 59, contre lequel vient buter l'extrémité du tronçon de gaine ;
• un étranglement 61 pour attacher le manchon au plot de positionnement 16 sur la paroi 15 délimitant le côté avant du moule, le ressort torique 22 du plot 16 venant en prise dans la gorge annulaire formée derrière l'étranglement 61 ;
• une partie tronconique 62 s'évasant vers l'extérieur et s'étendant de l'étranglement 61 vers l'extrémité frontale du manchon 58a,58b ;
• dans la partie tronconique 62, un renfoncement cylindrique 63 pourvu d'un taraudage intérieur 64 vers l'extrémité frontale du manchon, et d'une gorge annulaire 65, et dont le fond comporte un rebord annulaire 66 dirigé vers l'extrémité frontale.

In the embodiment illustrated in FIG. 7, the two sleeves 58 a , 58 b are parts having the same shape:

• a cylindrical part 59 for receiving the end of the sheath sections 10 a , 10 b ;
• an inner shoulder 60 at the end of the cylindrical portion 59, against which abuts the end of the sheath section;
• a constriction 61 for attaching the sleeve to the positioning stud 16 on the wall 15 delimiting the front side of the mold, the toric spring 22 of the stud 16 engaging in the annular groove formed behind the constriction 61;
• a frustoconical part 62 flaring outwards and extending from the constriction 61 towards the front end of the sleeve 58 a , 58 b ;
• in the frustoconical part 62, a cylindrical recess 63 provided with an internal thread 64 towards the front end of the sleeve, and an annular groove 65, and the bottom of which comprises an annular rim 66 directed towards the front end.

Positioning and sealing fitting 70 a a general form complementary to those of the parties frustoconical 62 and cylindrical recesses 63 of two facing sleeves, with a cylindrical bore central having approximately the inner section of sheath sections. To optimize sealing, the fitting 70 is provided with a series of radial notches 71 in the frustoconical part of its outer surface which make it more flexible, of two annular beads 72 which engage in the corresponding grooves 65 of the two sleeves and, on its two end faces, two respective annular grooves 73 which allow a bending of the portions having the beads 72 so that they engage elastically in the gorges 65 of the sleeves, and which define, towards the inside of the fitting, annular lips 74 coming to apply from sealingly against the annular edges 66 of the sleeves.

On only one of its sides, the connector 70 has a thread 75 intended to be screwed onto the thread 64 of one of the sleeves. This screwing is carried out on the sleeve of the element produced first, after its release. On the opposite side of fitting 70, there is no 75 thread, to allow easy assembly of elements.

The advantage of the embodiment of FIG. 7 is its lower cost taking into account the identity of the two sleeves 58 a , 58 b used.

Claims (11)

1. A process of manufacturing concrete construction elements including at least first and second matched elements (1a, 1b), the process including the steps of:

   placing in a mold at least one first pre-stress sheath section (10a) having an end connected to a first sleeve (18a; 38a; 58a) applied against a wall (15) of the mold, the first sleeve having an internal shape engaging a positioning boss (16) placed on said wall;

   pouring concrete into said mold so as to obtain the first element (1a) after setting of the concrete;

   extracting from the mold the first element, one contact face of which (7a) has been shaped by said wall;

   constructing a second mold one side of which consists of said contact face of the first element;

   placing in the second mold at least one second pre-stress sheath section (10b) having an end connected to a second sleeve (18b; 38b; 58b) held in position relative to the first sleeve by means of a positioning joint (30; 50; 70) resiliently held in at least one of the first and second sleeves;

   pouring concrete into the second mold so as to obtain the second element (1b) after setting of the concrete; and

   extracting the second element from the second mold, by disengaging the positioning joint from at least one of the first and second sleeves.
2. A process according to claim 1, wherein the internal shape of at least one of the first and second sleeves (18a, 18b; 38b; 58a, 58b) comprises an annular groove (24a, 24b; 44b; 65) to receive a complementary annular ridge (31, 32; 52; 72) of the joint (30; 50; 70).
3. A process according to claim 1 or 2, wherein the positioning boss (16) is provided with resilient coupling means (22) which engage with an annular groove (24a; 44a) present in the internal shape of the first sleeve (18a; 38a; 58a) in order to hold it in a removable manner in the mold.
4. A process according to any one of the claims 1 to 3, wherein the sleeve (18b; 38b; 58b) in which the positioning joint (30; 50; 70) is resiliently held has an angular opening of at least 30 degrees.
5. A process according to any one of the claims 1 to 4, wherein the positioning joint (30) is resiliently held in each one of the first and second sleeves (18a, 18b).
6. A process according to any one of the claims 1 to 4, wherein the positioning joint (50; 70) is screwed into one of the first and second sleeves (38a; 58a).
7. A process according to claim 5 or 6, wherein the positioning joint (30; 50; 70) has an orifice coaxial with the sleeves (18a, 18b; 38a, 38b; 58a, 58b) extending therethrough, said orifice having a cross-section at least equal to the internal cross-section of the first and second sheath sections (10a, 10b), and wherein the positioning joint (30; 50; 70) is left in place in the first or second sleeve after the extraction of the second element (1b).
8. A process according to any one of the claims 1 to 7, wherein the first and second sleeves (58a, 58b) are parts having the same shape.
9. A process according to any one of the claims 1 to 4, wherein the positioning joint is integral with the first or the second sleeve, and has an orifice coaxial with the sleeves extending therethrough, said orifice having a cross-section at least equal to the internal cross-section of the first and second sheath sections.
10. A construction work comprising an assembly of prefabricated elements made by means of a process according to any one of the claims 1 to 9 and including at least one pair of matched concrete elements (1a, 1b) having two respective contact faces of complementary shape (7a, 6b) and comprising at least one pair of respective pre-stress sheath sections (10a, 10b), the contact faces (7, 6) of the matched elements (1) being applied one against the other so that the sheath sections (10) are placed in the extension one of the other to form complete sheaths, with joints (30; 50; 70) engaged in the sleeves (18a, 18b; 38a, 38b; 58a, 58b) in order to sealingly connect the adjacent sheath sections, and wherein pre-stressing cables and a filling product occupy the interior of the sheaths.
11. A construction work according to claim 10, wherein an assembly adhesive is located at the interface of two matched elements, said sleeves and joints preventing this adhesive from penetrating into the sheaths.

Images