Process for producing hollow structures such as ducts, silos, or shelters, and structures obtained by this process

Disclosed hollow structures, having the shape of a cylinder resting on the ground by one of its generatrices or a similar curved shape.

Such structures are typically ducts of large cross section, for example beyond the Traditional industrial production of around 2 m²Buried or not, used for water supply or other fluid under pressure or without pressure, or for cable ducts and / or other conduits or Traffic and parking vehicles people.

The invention is also applicable to obtaining shapes similar structures but relatively short, used commes cellars, silos or fallout shelters or others.

Various techniques are used for carrying up conduits for the water supply, petroleum transport, cable ducts, or other ducts, etc ...

The most common technique is to use the tubular sections, a circular section, which are put together and assembled by various methods. This technique has drawbacks that increase with the diameter of the pipe, although it reduces the length of segments: manufacturing, transportation, handling and installation. Anyway, Also manufacturing problems, problems congestion arise as soon as one approaches a outer diameter of 2.50 m which corresponds to the limit normal road templates. For high flow rates, it is necessary to provide several ducts parallel, which is an expensive solution, or to contruire duct on site, according to technical masonry constructions or work in also expensive galleries and long delays production or realization.

It is also known from FR 733 098 or US Patent 2,400,071, consisting of technical assembling a large number of small elements dimensions each provided with transverse edges for assembly with adjacent components. The many elements requires to give them a same shape, which led to the adoption of a section circular in shape, and in this case, the resistance constraints requires that the junctions are alternating in the longitudinal direction. It was well planned in US Patent 2,400,071 to consider some stress exerted on the wall, and use for the upper part of the section of a tunnel elements to lower resistance for the part lower, but firstly a connecting joints alternating elements of different characteristics this uncertain strength, and secondly it introduces an additional complication in the assembly by mounting a large number of small elements, while such mounting is difficult to to execute a perfect way by a little personal qualified.

On the other hand, if the circular shape of the ducts is best suited to the case of high internal pressures and easiest to obtain when the manufactures portions corresponding to the entire section of the duct, it may, however, have drawbacks. Indeed, creates a circular duct, in soil that supports its weight, the constraints which present a maximum accused in its central region. It follows that if the soil is loose, differential settlements important can occur after installation.

In addition, the circular shape does not lend itself to a use of space when it is congested, as is often the urban case. Finally, the weight of the pipe is comparatively too high; in Indeed, the material is, in the case of unit links each covering the entire section, distributed so uniform over the entire periphery while the constraints are not.

To solve these various problems, we already have proposed to construct tubular conduits having a flattened shape in section to the base assembly by on-site longitudinal members prepared advance and each corresponding to a portion of the conduit cross-section.

DE-A-2157191 describes, for example, a cylindrical pipe that may base flattened and made of longitudinal elements assembled. Such elements are made of corrugated iron and are, in fact, a simple formwork will present, for large sections, a trèsfaible resistance to external stresses, which makes uncertain the shape retention of the section and sealing. Furthermore, the corrugations increase the resistance of the conduit to the fluid circulation.

To improve the flow, document FR-A-1027788, which relates to the production of a gallery underground flattened base proposes making the wall internal by assembling prefabricated reinforced concrete comprising, in cross section, a raft element forming a flat bottom, two sidewalls side and roof element.

Such a method is intended only to build coating a built tunnel gallery the ground up and is not applicable to performing a simply buried structure under fill.

Indeed, in the case of tunnel described in FR-A-1027788, wherein the lining elements are placed as and wherever digging excavation based on the portion of the coating already laid and they are then sealed by injecting cement between the elements and the rock wall. For this, the pieces fit together laterally in the other and therefore must be installed with a high accuracy. Is used, moreover, for this purpose, a special machine circulating in the gallery.

It is this machine that meintient upright each sidewall of a new section to its nest in the corresponding sidewall of the last section already laid and if there is an enlargement to the base, is to allow a connection round with the raft element. Such an expansion, which engages itself in a groove strike, would not be sufficient to ensure, with the security required, the vertical maintenance of the pier.

So we could not consider using such method for producing a pipe buried under an embankment, the wall must stand alone to solicitations the land and applied loads. In addition, we must also consider, in this case, the settlement differentials that can occur causing an offset of the adjacent elements. Such risk is negligible in the case of a completed tunnel underground in a necessarily stable ground and nothing is specifically intended to remedy in FR-A-1027788.

It was also proposed, in FR 1,008,441, to realize the wall of an underground gallery by means of four elements, respectively a base, two piers and a canopy. To realize, with the same base, several sections are used the vault elements covering different widths and the piers engage with play in grooves provided on the base so as to take various inclinations to adapt to the width of the vault. The piers must be calibrated in the desired orientation during its construction to allow the laying of the roof, and the assembly is blocked by casting a mortar into the grooves.

Such a construction method therefore requires that piers are wedged, before sealing, or on the rock wall or on scaffolding. Furthermore, it is not suitable for the production of pipes very. large cross section allowing, for example, traffic vehicles.

GB-A-13645 discloses, in the mode of embodiment of Figure 10, a structure comprising precast and resting on a foundation.

True, the document FR 2,223,513 expects to achieve small tunnels comprising, in cross section, two piers shaped boxes, fitted at the lower part of a broader basis for their to stand upright and, at their upper part, each a console on which a slab plane, a concrete slab being cast simply between the bases of the sidewalls which serve as formwork.

Such a method is intended only for the achievement galleries rectangular section and, in particular, we could consider replacing by circular arch-shaped elements the elements higher flat slab-shaped resting on the upper brackets.

But unless excessively increasing the reinforcement and the thickness of the planar sheet, the scope thereof, and therefore the width of the tunnel, will continue therefore limited.

In addition, adjacent elements are simply placed one on the other and it is provided no attachment to resist crushing differentials.

Thus, it appears that there is an unresolved need structures hollow, cylindrical, resting on the ground, in section flattened at the base form, in particular ducts important section, or similar structures, allowing to achieve structures having high mechanical strength and can withstand to differential settlement, with price production cost, transportation and introduction significantly reduced compared to technical current.

The invention therefore applies, a Generally, the realization of a hollow structure Big tubular cross-section, buried under an embankment, consisting of assembly and on the site prefabricated elements prepared in advance and being connected to one another along longitudinal joints and parallel respectively transverse joints and perpendicular to the axis of the structure, this latter comprising, in cross section four elements, respectively two side elements positioned on either side of a raft and on which rests an upper element, each side element having a sidewall substantially vertical and resting on the ground via a stabilizing element with a lower face flat allowing that element to stand right by itself.

According to the invention, the upper elements each have the form of a curved vault resting on the upper edges of side walls of the side elements and connecting tangentially to these demiers so give the structure a section substantially cylindrical in shape with a flattened base, said structure consisting of tubular sections placed end to end whose Prefabricated are positioned so that the longitudinal joints between elements of a same section are in the extension each other on either side of each transverse joint between two successive sections and the stabilizing elements are provided for allow the side members to stand upright by themselves by supporting the arch elements such that, for the realization of the structure, Prefabricated may first be placed in a manner permitting limited relative displacement adjacent elements and, when the land and surrounding the whole structure have stabilized, final assembly and rigid elements is formed at least along two longitudinal joints, said structure thus forming in form Ultimately, a homogeneous piece assembly.

In a preferred embodiment, the least the side elements and the raft are made concrete and allowed between the lateral sides of the raft and the basis of a range of side elements which extend frames comprising the parts extreme reinforcement elements we fallen behind during molding and said reinforcements are embedded in a cast sealing mortar in said interval, using formwork elements appropriate, to achieve the final assembly and rigid along the longitudinal joints items lower.

The invention presents a first advantage compared to the prior art, namely that transport is facilitated. If one assumes indeed that the maximum allowable dimension of 2.5 meters, Current technology only allows the unit transport outer diameter sections at most equal 2.5 m. If the elements of the invention correspond each one quarter of the channel section, the latter may have once finished a diameter of 3.5 m approximately, a dual surface section, and if the elements corresponding to one sixth of the section, it may have once finished diameter 4.4 m is about a triple-sectional area. Of Moreover, for the same height of 2.5 m can be available, in the same volume, a considerable number of unit elements, stacked on top of each Other so. the same transport vehicle will be used to its maximum payload. On the other hand, the total length of joints to be performed by welding or otherwise, is obviously increased. he be observed that it is normally rectilinear seals which are much easier to obtain or perform that circumferential seams, and that the number of these demiers may instead be reduced due to the more high unit length of the elements, allowed by unit weight more reduced.

Another advantage of the invention results from the non-circular shape of the structure, it was noted High disadvantages of a circular shape.

In addition, thanks to the shape of the flattened section basis, a considerable improvement is obtained stress distribution generated in the ground underlying and movements thereof can be reduced dramatically. Another advantage such forms is a lower height section equal, hence reducing the search costs (Earthworks, shields, groundwater drawdown water, etc ...). On the other hand, when the consistency the carrier requires soil (including groundwater) can be integrated in a duct obtained ballasting by means of masses of metal or concrete come mistletoe cling, by an appropriate bolting, you the strike said duct. Of course, the mass of lestaqe is calculated based on specific data site concerned and each of the weight members can also be prefabricated. We can also anchor the ground led by the same bolting process which is made easier from the inside the flattened shape of the raft.

On the other hand, the precalculation of constraints which shall be subject to the elements conduct and use of the results of this calculation to determining the thickness of each element, the variation this thickness from one point to the other of the section, the material of which is made each item and situation of longitudinal joints, offer advantages important:

It is common, in fact, that the upper part a conduit has a protective function and is subject to limited restrictions. On the other hand, weight of the transported fluid, when it is water or another liquid in free flow, obviously more at the bottom than at the top. Furthermore sealing the obtained assembly seals authorizes leads him to withstand pressures and internals, thereby to be used in penstock. We will note also that in its final form, the duct forming a homogeneous batch and single-piece, it will not be necessary to make stops to changes direction, driven generators longitudinales.La possibility of adapting the thickness and material element allows for significant savings on the cost and transportation.

As mentioned above, the various elements can be of different thicknesses depending on the result calculating contraintes.lls can also be made with different materials, provided that, where appropriate, the necessary precautions have been taken to prevent corrosion effect electrochemical couples.

Preferred materials include, for their low prices and their facilities for obtaining and assembly by welding and / or other means, ductile iron, but other materials may be envisaged alone or in combination, such as steel, aluminum alloys, other metals, reinforced plastics or non-fiber, concrete armed or not, prestressed or not. In the last two case, it is obvious that the welds which have been mentioned above are replaced by links appropriate.

In the case where the pipe members are made by piece molding or by profiling section continuously, in particular by extrusion, materials such as ductile iron, steel, reinforced concrete, these resins, etc ...., is advantageously a mold or tool whose cross section is shaped so as to reproduce by acting on the surface interior of the conduit element, the aforementioned variations of optimum profile and likewise the transverse variation thickness.

The directional changes are obtained by precast curved or canted especially calculated and adapted to the geometry imposed.

The making of a conduit according to the invention, that is to say by elements that represent only a part of the section but yes can, for compensation, be of considerable length, is problematic specific time of assembly; these problems were solved by the mode following assembly, which is thus in association closely with the main object of the invention. according to this mode, performs the initial assembly of the elements by linking them both longitudinally and transversely by means for a limited relative movement of adjacent elements by interposing between them a sealing gasket flexible material, and is then carried to the assembly final and rigid elements between them when the surrounding land and the entire duct is stabilized. Preferably, the initial assembly of the elements between them is made by means of bolts passing through at least one of the elements through a hole extended accordingly.

However, other connecting modes can be more advantageous, particularly in joints where strong constraints impose thicknesses Important walls. In these cases, it is preferred to operate according to one or more of the following methods.<ul><li>to realize the longitudinal seam and possibly cross connection elements duct is formed from the recesses or projection placed in the zones of corresponding edges and engageable by conjugation forms and / or strengths to create joints necessary longitudinal and transverse;</li><li>for creating longitudinal joints, one form a rib on each of the edges of two elements to be joined and are distributed along the two and ribs formed of the locking means;</li><li>the locking means are rigid calipers or elastic;</li><li>the brackets are fixed using rigid parts or elastic-fitted between the inner surface of the stirrup and the flank of the corresponding rib or by elastic deformation stirrups themselves;</li><li>sealing liners, a profiled section in correspondence to the edges of the longitudinal joints and transverse, are interposed between said edges and is sealed collet provided using said stirrups or using necklaces, hoops, prestressing cables or other means;</li><li>in cases where the elements are formed of weldable or sealable material, the longitudinal joints and transverse are made by addition of material welding or sealing correspondingly.</li></ul>

To facilitate the establishment and the stabilization of the pipe, there are provided elements stabilizers triangular longitudinal section, on the sides of the bottom face of the pipe. These elements have a horizontal flat face which is approximately at the bottom of the conduit, one face plane approximately vertical or indinée, and a face that matches that of the pipe. These stabilizing elements are preferably discontinuous and implanted place to place along the pipe to prevent the lower member to tilt about its longitudinal axis after its establishment.

These stabilizing members may be attached by bolting, welding or the structural element driving. In the case where it is obtained molding (concrete) they can also make body him.

Further interest in the stabilization of the whole conduct, the stabilizing elements are advantageous if the conduit is formed some elements which constitute the bottom and other of the side walls with an orientation vertical general: by providing that elements stabilizers are fixed in advance on the elements of lateral wall, or are in one piece with these elements, they become able to stand upright resting on the ground, which facilitates obtaining their junction with the substantive elements posed first. Then, the establishment of the elements forming the top can be effected by placing the on the side wall elements.

According to another method of obtaining seals used, in case the elements are made concrete or other cast material, is provided on the edges of the longitudinal elements, ledge material weldable or bondable on which is fixed, after installation and, preferably after stabilization, flat pieces for sealing a material compatible with the angle profiles.

In some cases, particularly when it comes to transport or store hazardous fluids, or the construction of fallout shelters should be to obtain a perfect seal even in case of landslides or explosion nearby, and if the elements are made of concrete or other material may crack or lose its tightness in another way, it is advantageously provided a waterproof lining or lining, solidarity or not the structural elements.

In some cases, this coating may be a lost formwork section for the elements of the structure.Si the coating consists of sheet metal or other material metallic or non-metallic weldable or bondable, of flat parts of the above mentioned type can be welded or glued to the sealing that coating, or can weld or glue directly coating parts together at points.

If the structure, leads or shelter, is formed of elements concrete, this provides the resistance to crushing, However, a liner sheet or metallic or non-plastic, welded, glued or applied by any coating provides a seal the absolute contamination or seepage, radioactive or other, even if the movements of the field or explosion due to the distorted structure.

The following examples mainly relate to large-section conduits, but it is easy to realize that what is said is also valid for silos, shelters or similar structures.

In the case of an anti-atomic shelter prefabricated, is placed longitulinale wall elements, which may be constituted in the same way that for large section ducts, and the shelter is closed at its ends by flat transverse walls or curved. Preferably, we give away a background substantially flat, and the basic elements or side are provided with lateral stabilizing elements, integrated during manufacture or subsequently added, so as to prevent a tilting of the shelter around its longitudinal axis.

Advantageously, an inner lining is provided waterproof, especially if the shelter is built in concrete.

The shelter can be set up very quickly because it consists of separate elements that can carry to be easily assembled on site. he can be placed in an excavation which is then corked, or even in some instances be simply placed on the ground. Note that the shape flattened base provides improved resistance to blast effects, with respect to a cylindrical shelter Brick or parallelepipedal.

The invention will now be described in more detail using embodiments, non-limiting, illustrated by the drawings among which some embodiments shown in particular Figures 1, 2 and 17, do not comprise, in cross section, four elements and not within the scope of protection defined by the claims:

FIGS. 1 to 3 are schematic cross-sections ducts.

Fig. 4 is a partial section showing a mode assembly.

Fig. 5 is a diagrammatic perspective view a conduit in which the various sections are formed of longitudinal elements whose longitudinal joints and transverse assembly are highlighted.

Fig. 6 shows an example of elements of conduit having a gradual reduction radial thickness toward the center.

Fig. 7 shows an example of elements of conduit having a gradual increase transverse thickness of the left to right.

Fig. 8 is a cross section of a longitudinal joint showing a rib stitch mode and calipers.

Fig. 9 shows an example of profile interlocking the corresponding edge of two elements conduit to form a longitudinal joint or transverse.

Fig. 10 shows another example of profiling elements of the edges to form a longitudinal joint or transverse.

Fig. 11 shows yet another example of profiling elements of edges to form a longitudinal or transverse seal.

Fig. 12 shows an embodiment of a transverse joint interlocking whose seal is provided by a specially profiled annular seal that is compressed using a suitable strapping.

Fig. 13 is a cross section of the conduit Figure 12, showing the cerclage gasket.

Fig. 14 shows the establishment of a joint in the case of reinforced concrete elements.

Fig. 15 is a diagram illustrating results constraints calculations.

Fig. 16 is a section through a frame section hollow concrete corresponding to the calculation of Figure 16.

Fig. 17 shows a conduit specially adapted to ducts little section.

Fig. 18 shows a method of obtaining the seal of the seal.

Fig. 19 shows a fastening of the joint.

Fig. 20 shows another method of production of sealing.

Figure 1 shows, in solid lines, cutting a duct 1, and comparison dashed cutting a circular duct 2 of the same section. The conduit according to the invention is obtained by assembling four same elements length.

The base member 3 is substantially plans; two side 4 elements have a curvature variable stronger downward than upward; the profile is completed by an upper member 5, in section arc. The example shown corresponds to indication to a section of 10 m². The height H Total is 2.40 puts off L 5,00m, compared with the diameter D of circular corresponding conduit, which is 3.57 m. The excavation necessary for the duct of the invention is wider at the base than for the circular pipe, but it is shallowest; and in total, the volume to be excavated may be lower and work more easy.

2 shows another form of conduit, in which background elements 3<u>at</u>are slightly curved, and having two elements top 5<u>at</u> instead of a.

Figure 3 shows yet another embodiment, Mistletoe has the feature that the bottom part 3<u>b</u>forms a central cunette 6. It was expected that the cunette is in the middle of the element 3<u>b</u> and is slightly flared so that the elements are identical and stackable for transport, but Naturally, other arrangements are possible. following the conventional technique, the addition of a culvert poses a virtually insoluble problem.

4 illustrates an example of connection mode between two elements 4, 5 placed as elements 4<u>at</u> and 5<u>at</u> of Figure 2.

The element 4 is provided in a first phase a connecting plate 7, fixed by a weld 8, which can be executed or factory square. This plate 7 has widened holes 9, which, during assembly, are in correspondence with enlarged holes 10 of element 5. When assembly is interposed between the element 5 and the plate July 1 flexible joint 11 elastomer or the like, then is carried to the junction with the aid of a screw 12 and a nut 13.

when the set of elements corresponding to the section Next the duct is fitted, light movements on items 4 and 5 may appear, eg under the level variations of the effect bottom of the excavation. Slight movements can also be the consequence of the settlement of land Underlying. All these movements are possible by enlargement of the holes 9 and 10. When these movements have continued to occur, we can proceed with the final junction of elements a weld 14. The screw 12 and the nut 13 can further be deleted, and the holes 9 and 10, or only one of the two, can be closed by welding.

In Figure 5, there is shown in perspective view schematic conduit obtainable by the process according to the invention. this conduit comprises longitudinal elements such as A1, B1, C1, etc ... for the first section A '1, B' 1, C '1, etc ... for the second segment, and so on; these elements are interconnected by longitudinal seams, JL1, JL2, JL3, JL4, etc ... and by joints cross JT1, JT2, JT3, JT4, etc ...

It is interesting to give to the cross section at least some of said elements a thickness variable to suit the stresses exerted at different points of the section of the element considered. Thus, it was demonstrated in Figures 6 and 7 cross-sections of duct elements showing how to vary the thickness of matière.Cette feature is extremely important, both for manufacturing as for transportation and assembly of the element since the amount of material, and consequently the weight and the price of returns are defined, in the most accurate manner possible, according to the parameters reacting achievement the final duct. If we consider the application of the invention to the construction of oil pipelines, aqueducts, etc ...., long lengths, it becomes easily accommodate the influence of a weight gain of finate the profitability of execution of the work.

The duct elements according to the present invention can be made of different materials and be manufactured, in correspondence, for different processes. Thus it is possible to consider manufacturing elements such as A1, B1, C1, etc ... in a metal such as ductile iron, graphite cast thy spheroidal, steel, aluminum alloys, etc ... For such materials, it is possible to in practice various methods such as the cast piece by piece, the continuous casting, spinning, forging, the differential rolling, etc ... All these processes can realize a way homogeneous from the recesses or protruding front subsequent use, during assembly of the elements, to the property of longitudinal seams and cross, as will be explained below.

It is also possible to carry items duct made of other materials than metals, especially reinforced concrete, of plastics or resins reinforced or not with fibers, ect ..... In such conditions, the elements are made by molding to the flange of molds or forms, who also used to obtain the parties projecting and hollow above.

Any implementation of materials processes defined above for the realization of elements pipe according to the invention involve tools, molds, forms, etc ..., which have consider the characteristics of the process obtaining ducts according to the invention in following conditions:<ul><li>the inner surface of the duct element made must match the ideal profile section of the conduit, determined by calculation based on known parameters the concertante type of installation, the conditions of use of leads and intrinsic caractéristigues. By "ideal profile" means in the job of a conduit where the external conditions vary little, an average profile applicable to this conduct over a certain length,</li><li>each element must submit the dimensions Overall for assembling it with the other elements of the duct and the different thicknesses of elements should be calculated to enable them to withstand the stresses which they are subject.</li></ul>

The final sealing is obtained by various appropriate means each material used, it is created from the inside of the duct, after stabilization final (settlement, compensation for expansion, compacting, etc ...).

We will now describe how is assembling the various elements to form a duct, with reference to Figures 8 to 12 which give some embodiments of longitudinal joints and transverse joints. ANSI is shown in cross section in Figure 4 a longitudinal joint established between the two duct elements A1 and B1. In this case there is provided, on either side of points defined by the two surfaces of the elements 71,72 A1, B1, external longitudinal ribs 73,74 respectively which extend over the entire length of the elements of the corresponding duct. These ribs may be formed during casting, spinning, rolling, or molding elements correspondents or they may also be reported by welding, in which case they can be discontinuous. These two ribs provide as shown in Figure 8, the simple and effective fixing a locking stirrup 79, with corners 76,77 which are fitted in position between the bracket and the rib in corresponding operating for example by hammering or other similar process.

To absorb the reactions acting in a direction perpendicular to the section profile duct, it is appropriate to leave surfaces lateral delimitation of conduit elements A1, B1, etc ..., forms allowing them to absorb constraints in the best way possible, account Given all the parameters relating to the conditions manufacture and use of the duct, and also the material of which it consists. Thus, as examples Non-limiting gave in Figures 8, 9 and 10 some models of profiles of said surfaces lateral boundary of duct elements On Figure 8, the boundary surfaces 71 and 72 are inclined relative to the plane perpendicular to the profile of the duct section. Such profiling surfaces Seal suitable for example when the static charges acting on the conduit are predominant.

In Figure 9, the two delimiting surfaces side of the conduit elements A1, B1 which are designated 79 and 80, have rounded shapes corresponding to absorb the reactions acting in both directions in said plane perpendicular to the section profile.

In Figure 10, surfaces there is shown delimitation 82 and 83 which form steps for to make a nest.

In Figure 11, there is shown the profiles 33 and 34 defining a cavity 35 can be filled yes by a sealing material for example a casting resin.

It should be noted that all these shapes of the surfaces lateral boundary of duct elements can be perfectly made by any aforementioned manufacturing methods. To establish a good seal, is provided in each case between the corresponding surfaces of the longitudinal joints above, coatings, sealants, liners or other sealing establishment staff, including rubber, natural or synthetic, as respectively indicated at 8 in Figure 8, in 81, on Figure 9 and 84 in Figure 10.

It should be noted in this regard that these seals provide a pressure seal.

In FIG 14, a longitudinal seal is shown which is established between two duct elements A1, B1 made of reinforced concrete. It has designated 20 and 21 the respective frames of the elements A1, B1. For realize the junction, the frames are allowed to exceed 20, 21 during molding of the elements and, once demiers these were set up in the positions provided on the installation location of the conduit, is connected together the end portions of the projecting respective frames, as indicated at 22, and then, using suitable shuttering elements such 26, casting a sealing mortar in 21 the gap in order to achieve the longitudinal seam considered.

In FIG 14, it was revealed at 24 and 25 angular hollow profiles and connecting edges A1 elements B1. These profiles are designed firstly to facilitate the attachment of mortar seal 23, and secondly to improve the seal of the joined by creating discontinuities for deleting leakage paths localized. It was designated by 27 and 28 of the formwork of the holding members 26 which is fixed position with the nuts 29, 30.

In Figure 12, an example is shown making a transverse joint between two sections respectively formed by conduit elements such as A1, ..., and elements such as A'1.,. etc ... It was designated by 15 and 16 the boundary surfaces the transverse seal. In the example, there is provided a designated peripheral seal in a whole by 17 and comprising firstly a mistletoe radial bead fits into the range existing between the surfaces 15, 16 and secondly by a peripheral ring whose inner surfaces are applied against the outer surfaces elements respective conduit, said ring having on its outer surface of périphérigue parts in relief 19, designed to be flattened by compression with a cerdage or collar 18A, 18B, as shown in Figure 13 which is a sectional cross the duct of Figure 12. In the example considered, given without limitation, the parties Relief 19 may have a profile dovetail and include divisions in their slots to create a seal type labyrinth. strapping Flattening is made in two parts 18A, 18B interconnected by turnbuckles 31, 32 mistletoe are operated for the final tightening.

It should be noted that although all the examples of construction of joints between duct elements do not not involve bolting, such a process is absolutely not excluded and that it is possible to form or set on elements like parts at the edges and flanges mistletoe would then assembled with bolts or similar bodies.

In some applications, it is possible in the scope of the invention, to adopt for the conduit a Joint structure, that is to say to use a quarter of elements formed of a first material, e.g. reinforced concrete, in a first portion of the conduit, for example in the lower part between the and longitudinal joints JL1 JL4 in Figure 5, and the other elements formed of a second material, for example a metal or plastic reinforced or not fibers in the remaining portion of duct. Such a composite structure may be recommended in a water supply work in trench open, that is to say without heavy loads on the top of the duct, in a remote area where it is profitable to manufacture the bottom reinforced concrete molded and the upper part by thin elements, prefabricated in factory and transported to site.

15 shows, in solid lines in the form of the neutral fiber of a duct section according to the invention (Curve I), dashed (curve II) distribution bending moment corresponding to the vertical thrust land and alternating lines (curve III) the distribution of the bending moment corresponding to the lateral earth pressure. The complete calculation further comprises determining a number similar curves, corresponding, for example, the internal pressure in the proper weight conduct, etc .... The calculation then includes combining results each corresponding to a type constraint.

It is observed that the full profile section There are four areas of "knots", situated one lower part of the pipe, the other towards its part high.

Figure 16 shows the half-section of a conduit consists of four reinforced concrete.

It is observed that the thickness (h₁, h₂) in the areas that correspond to the highest stresses Figure 15, that is to say the center of the base and on the sides is about 50% greater than the thickness h₃ sommet.Les JL1 the junctions between JL2 elements were set the node areas constraint. In this figure the benchmark f₁ means reinforcing rods embedded in concrete elements prepared in advance and f₂ designates the anchor chains, which have been folded over each other before being embedded in the concrete during the construction of the structure.

Figure 16 shows in phantom an element stabilizer 41. This figure shows a Another advantage of the stabilizing element in the case of a structure whose cross section is formed more two elements. We see in fact that the element of A2 side with the 41 outer stabilizing element may remain only in the final position. It therefore has no need to provide interim support for achieving JL2 junction with the element base A3.

Note also that in the case of a structure placed on the ground, the stabilizer increases the element resistance to lateral forces to overthrow the structure, which is advantageous in the case of a shelter anti-nuclear or other, which would be placed on the ground and exposed to blast effects.

18 shows an embodiment of seals in the case where the elements are in material or weldable or bondable, for example by concrete :

Each element A1, A2 is on its edges angle 43 of weldable material or bondable, by eg ferrous metal, established at the if the molding element is obtained in this manner. dishes members 44 or other connecting elements dishes weldable or bondable material on the corner posts 42 are welded or glued thereon, optionally after soil stabilization.

19 shows another assembly means structures according to the invention.

One of the elements A1, has a threaded hole 45, which may be provided in an insert 46. The threaded hole being directed approximately perpendicular to the plane of seal. The other element A2 has a shoulder 47 a hole 48 in which is inserted a screw 49 which screws into the hole 45 crossing with the game hole 48.

20 shows another embodiment of gasket sealing, wherein the elements A1, A2 concrete, are internally provided with a coating sealing sheet 50, shuttering perdu.Un flat element 44 is then welded inside directly on the coating 50. A bracket, similar to that of Figure 18 may be provided on the other edge of the elements A1, A2.

It is observed that a number of provisions of assemblabe described above are used for the establishment of the conduit and do not intervene not to contain alone in an essential way, the hydrostatic pressure in the case of use penstock in these hydrostatic pressures being partly offset by the surge in embankments.

To better secure the elements of a duct, shelter or other and facilitate the achievement by points, one can possibly predict more cables prestressing forming strapping, cables or bars prestressed interconnecting longitudinal members adjacent in the lengthwise the each other. These cables or bars can connect each of them at least two consecutive elements, for example, an element may be connected to the element which follows by a set of cables or bars, and the preceding element by a similar game, which allows to operate the prestressing gradually measuring the progress of the installation. One can foresee also that each cable or pre-stressed bar connects three consecutive elements or even more.