Process for obtaining hollow structures such as ducts, grain tanks or shelters.

A hollow body having a cylindrical inner wall, and a method of making a tubular duct from such bodies. A hollow body with cylindrical inserts and a fitting for the manufacture of a tube is provided.

The invention relates to a hollow body having a cylindrical inner wall, preferably deviating from a circular shape, formed by juxtaposing tubular portions, each of which is assembled by juxtaposing prefabricated elongate components each corresponding to a cross-sectional portion of the hollow body wall.

The invention further relates to a method of manufacturing a pipe duct bounded by a cylindrical wall, preferably deviating from a circular shape, by installing prefabricated longitudinal components, each corresponding to a cross-sectional part of the hollow body wall, by superimposing the components on at least two longitudinal joints namely, a lower component forming the base, which is preferably flat-bottomed and supported in the ground, and at least one upper gutter-like component which forms a vault.

Such structures are typically large cross-section pipelines, for example larger than conventional industrial products of about 2 m 2, which may be above or below ground for transporting water or other liquids that may be under pressure, or may also be cabinet or dirt or pedestrian or pedestrian or pedestrian or vehicle lanes.

The invention can also be applied to pipelines with a small cross-section, for example up to 1 m2. It is also suitable for the production of similarly shaped structures which are relatively short and which are used as chambers, silos or bomb shelters.

Although the invention is substantially described with reference to large cross-section pipelines, the invention is not limited to these.

Various techniques have been used to install pipelines, for example, to transport water or oil products, or for other cables or conductors.

The most commonly used technique involves the use of bodies of circular cross-section mounted against the head by various methods. In this technique, the inconveniences of fabrication, transportation, handling, and installation increase as the diameter of the boom line increases, even if the length of the parts is shortened. In any case, in addition to manufacturing problems, problems with the size of the cutting surface arise after the outer diameter has reached a value of 2.5 m, which corresponds to the normal limit for road transport. To transport very large volumes of liquid, parallel pipelines have to be arranged, which is an expensive solution, or the pipeline has to be fabricated on site according to concrete construction technology or the work has to be done in underground tunnels, which is also expensive and time consuming to manufacture or build.

In addition, as is known, a tube with a circular cross-section3

7731 3 wires are best suited for high internal pressures. Such a cross-section is easiest to fabricate when fabricating the entire cross-section or circumferential surface of a pipeline. On the other hand, such a circular cross-section has disadvantages in other uses. The circular cross-section pipeline creates stresses in the support surface where the maximum load is in the middle. As a result, if the soil is loose, considerable subsidence may occur after the pipeline is installed. Pieces with a circular cross-section are ill-suited to the cramped spaces of an urban environment. Finally, the weight of the pipeline is relatively large; the material is in a uniform piece in the shell, covering the entire cross-section or sheath evenly distributed along the entire circumference, while the stresses are not distributed in this way.

To overcome these various problems, it has been proposed, see for example German Patent 2,157,191, to construct pipelines in which the cross-section is smoothed from their bottom by installing on-site prefabricated elongate members each corresponding to a circumferential or cross-sectional part of the pipeline. Such structural components have low mechanical strength with respect to external forces, so the preservation of appearance and fluid tightness is uncertain. Further, the corrugation increases the flow resistance.

French Patent 733,098 and U.S. Patent 2,400,071 disclose techniques for installing large numbers of small size components, each with transverse flanges for mounting adjacent components. The large number of components means that they must be identical in shape, which results in the use of a circular cross-section and, in this case, stress resistance4.

7731 3 requires that the joints vary in the longitudinal direction. U.S. Patent 2,400,071 takes into account the stresses on the pipeline wall and uses components at the top of the tunnel that are lower in strength than the components at the bottom. However, the variable joints of components with different properties cause uncertainty in terms of strength and, in addition, this brings with it an additional difficulty in installing a large number of small components, which is difficult to perform satisfactorily with the help of unskilled workers.

Thus, there appears to be an unsatisfied need for a method of making cylindrical hollow structures, especially large cross-section pipelines, resting on a single, flat cross-sectional side, which method produces structures with high mechanical strength and fabrication, have been significantly reduced compared to current technology.

According to the invention, the hollow body is characterized in that each tubular part consists of at least two components in cross-section, namely a lower component preferably with a flat base and two sides provided with external, substantially triangular cross-sectional stabilizing members with horizontal undersides for horizontal installation. , and the upper component, having an inverted trough shape to accommodate the sides of said lower component to be supported along the joints between the components.

According to a preferred embodiment of the invention, it is arranged that the lower component comprises three elements

7731 3 ti, namely a flat bottom element and two side elements provided with external stabilizing members which allow them to be placed on the sides of the base element so that they remain upright on the ground, in which position they form a support for the upper gutter-shaped element.

According to another preferred embodiment, it is provided that the shape and dimensions of the components, and in particular the curvature, thickness and material of construction, are determined for each component separately by calculating the optimum loads as a function of known parameters including installation location, pipe operating conditions and internal properties. proximity to nodes, i.e. to points where the absolute value of the stress in a direction perpendicular to the wall of the component passes through the minimum point.

The method according to the invention is characterized in that the stresses to which each component is subjected during use are pre-calculated as steps in the method, taking into account known parameters concerning location, operating conditions of the duct and its internal properties, determining the shape of longitudinal components that at least some of the longitudinal joints between adjacent components are located in the vicinity of the stress nodes, i.e. at points where the absolute value of hollow body transverse stresses passes through the minimum point when calculating the stresses to which each component is subjected to each component and using the results to determine the exact curvature, to determine.

7731 3

The first advantage of the method according to the invention compared to the current technology is the ease of transport. Assuming a maximum permissible dimension of 2.5 m, current technology allows the transport of a single piece with an outer diameter of no more than 2.5 m. If the components of the invention each correspond to a fourth final pipeline, the latter may have a diameter of about 3.5 m, or twice the cross-sectional area, and if each component corresponds to one-sixth of the final pipeline, the latter may have a diameter of about 4.4 m or three times the cross-sectional area. With a further height of 2.5 m, a considerable number of uniform components stacked on top of each other can be accommodated in the same space, so that the transport vehicle can carry the maximum permissible load. On the other hand, the total length of joints that have to be made by welding or otherwise has increased. It should be noted that they are generally large seams that are much easier to manufacture than circular seams and, conversely, the number of seams may decrease due to the longer unit length of the components, which is possible due to the reduced unit weight.

Another advantage of the invention follows from the non-circular shape of the outer surface of the structure; the disadvantages of a round pipeline are outlined above.

Furthermore, thanks to the flat cross-section, a considerable improvement in the distribution of stresses in the adjacent ground is achieved and its movements can be greatly reduced. Another advantage of such a cross-sectional shape or profile is the lower height in a given cross-sectional flow area, thus reducing trench costs (excavation, support and groundwater retention, etc.). On the other hand, if the composition of the supporting soil so requires (especially aqueous formations), the weight load can be installed in the pipeline suitably by means of metal masses or concrete screwed under the bottom wall of the pipeline. The weight of the weight load must, of course, be calculated from the actual one

II

7731 3 according to the actual conditions of the construction site and each weight load element can be manufactured in advance. The pipeline can also be anchored to the ground by the same bolting process made easier due to the flat shape of the bottom wall.

Furthermore, the pre-calculation of stresses on pipeline components and the use of calculation results to determine the thickness of each component, the thickness variation of the transverse section from point to point, the material used in the component and the location of the longitudinal joint offer important advantages:

Often, the top of the pipeline has only a protective function and is subject to limited stresses. On the other hand, the weight of the fluid transported, when it is water or other free-flowing fluid, apparently loads more at the bottom than at the top of the pipeline. Furthermore, the fluid tightness in the manifolds allows the pipeline to withstand internal pressure and therefore can be used to transport pressurized fluid. It should be noted that since the final structure of the pipeline is uniform and completely uniform, it is not necessary to arrange changes of direction at the joints that cause longitudinal pressures. The ability to match the thickness of the component and the material used allows large savings in production and transportation costs to be achieved.

As discussed above, different components may have different thicknesses depending on the results of the stress calculations. The components may be of different materials and, however, adequate precautions must always be taken to prevent corrosion by electrical pairs.

Due to the relatively low price, easy availability and weldability or assembly by other methods, the recommended materials are forging cast irons, but other mate8

7731 The 3 rials may be indicated singly or in combination, such as steel, aluminum alloys, other metals, fiber-reinforced or non-reinforced plastics, prestressed or non-prestressed reinforced concrete or concrete. In the latter two cases, it is obvious that the above-mentioned welds must be placed in suitable places.

When the pipeline components are cast in one piece or extruded as a single profile from materials such as forged cast iron, steel, reinforced concrete, resins, etc., a mold or pad is used whose transverse shape is such as to provide the optimum profile of the pipeline component.

Changes in direction are achieved by curved or angular prefabricated components that have been specifically calculated and fitted to the existing geometry.

The manufacture of the pipeline according to the invention, i.e. the manufacture of (partially cylindrical) components which correspond only to a part of the cross-section or circumference, but which may instead be very long, poses special problems at the time of installation. The problems have been solved by the following installation procedure, which is therefore closely linked to the main feature of the invention. According to this embodiment, the components are initially assembled by connecting them both longitudinally and transversely with members that allow limited relative movement between adjacent components with flexible seals installed between them, and then rigid component assembly is performed after the surrounding soil and entire pipeline have stabilized. . Preferably, the initial assembly of the initial components with each other is performed by screws passing through the enlarged openings in at least one of the components.

7731 3

Other even more advantageous ways of installing components can also be found, especially in joints where high stresses require high wall thickness. In such cases, one or more of the following methods must be recommended.

In order to make longitudinal joints or alternatively transverse joints of the pipeline components, recesses or protrusions are provided in the respective edge portions of the adjacent components and shape and / or power joints are provided to provide the necessary transverse and longitudinal joints.

In order to provide a longitudinal connection, a thickening is formed on each edge of the two components to be connected and the fastening members are fastened to the thickenings at a certain distance from each other.

The fastening members are rigid or flexible U-shaped members.

The fastening members are fastened with rigid or flexible spacers, which are forcibly fitted between the inner surface of the fastening member and the flange of the corresponding thickening, or by means of a flexible deformation of the actual fastener.

The seals or sealing members have a cross-sectional shape corresponding to the edges of the transverse and longitudinal joints and are placed between the edges and their fluid tightness is ensured by fasteners, flange rims, prestressed cables or others.

In the case where the components are made of a material to be welded or soldered, the longitudinal and transverse joints are provided by additional amounts of the corresponding material to be welded or soldered.

7731 3

According to an interesting embodiment, which facilitates the installation and stabilization of the pipeline, triangular longitudinal stabilizing members are arranged on the sides of the lower surface of the pipeline. These stabilizing members have a planar horizontal side approximately planar to the bottom of the pipeline, an approximately vertical or inclined planar side, and a side conforming to the side of the pipeline. The stabilizing members are preferably separate and spaced along the pipeline, preventing the subcomponent from rotating about its longitudinal axis after installation.

The stabilizing members can be fastened to the corresponding structural components of the pipeline with screws, welding or other means. If the pipeline is cast (eg concrete), they can also be made integral with it.

In addition to stabilizing the entire pipeline, the stabilizing means are also advantageous when the pipeline is formed of components in which the bottom and the side walls are generally vertical in some. By attaching the stabilizing members in advance to the side wall components or forming them in one piece with the side wall components, the latter can remain upright, supported on the ground, which facilitates the connection with the bottom wall components which are brought into place first. The top wall components can then be installed by placing them on top of and on the side wall components.

If the cross-sectional area of ​​the hollow structure is relatively small,

For example, the pipeline is about 1-4 m, the entire outer circumference can be formed by only two components, one corresponding to the lower part and the sides of the pipeline and the other forming a cover. Such components have at least a part that can be made of concrete or other casting or casting material.

According to another method of making useful joints

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7731 3 if the components are made of concrete or other casting or casting material, corner parts of weldable or solderable material are arranged on the edges of the longitudinal components, on top of which, after positioning and preferably after stabilization, planar sealing members are made of material corresponding to the corner members.

In certain cases, especially when transporting or storing hazardous liquids, or when designing bomb shelters, full sealing is required even when the soil is moving or near the explosion site, and if components are made of concrete or material that may rupture or otherwise lose fluid tightness, preferably liquid tight. a liner or cover that can be attached to structural components as needed.

In some cases, the liner may form part of the permanent coating of the structural components. If the liner is made of metallic or non-metallic or other weldable or solderable material, the above planar members may be welded or soldered to the joints of this liner or the liner portions between the planar portions may be welded or soldered directly thereto in the plane of the joints.

If the structure, pipeline or shield is formed of concrete components, the collapse resistance is provided by concrete components and a metallic or non-metallic sheet or plastic liner, with a welded or soldered sheath providing absolute

The following examples are relevant to large cross-section pipelines, but it is easy to understand that they are

7731 3 equally applicable to silos, shelters or similar structures.

The longitudinal wall components of the prefabricated bomb shield are positioned in the same manner as in the case of large cross-sectional pipelines, and the shield is closed at its ends by planes or convex side walls. Preferably, the shield has a substantially flat base and the base and side components are provided with stabilizing members joined during or after manufacture, and prevent the shield from rotating about its longitudinal axis.

The inner liquid-tight liner is preferably arranged, especially if the cover is constructed of concrete.

The cover can be installed very quickly because it is made of separate components that are easy to transport to the desired location for installation. It can be installed in a trench that is then filled or, under certain conditions, it can simply be placed in the ground. It should be noted that the flat housing design provides greater explosion resistance compared to masonry cylindrical or similar shields.

The invention will now be described in more detail with reference to the accompanying non-limiting application examples shown in the accompanying figures.

Figures 1-3 schematically show a cross-section of a pipeline according to the invention.

Figure 4 shows a cross-section of an installation method.

Figure 5 schematically shows a perspective view of a pipeline

7731 3 of the various parts of which are formed by longitudinal components whose seams are shown.

Figure 6 shows an embodiment of a pipeline component in which the radial thickness decreases as a function towards the center.

Figure 7 shows an embodiment of a pipeline component in which the transverse thickness decreases as a set from left to right.

Figure 8 shows a cross-section of a longitudinal joint with its thickeners and fastening members.

Figure 9 shows an embodiment in which the fitting edges of the two pipeline components are formed to form a longitudinal or transverse joint.

Figure 10 shows an embodiment with an overlap joint between the edges of the components to form a longitudinal or transverse joint.

Figure 11 shows another edge structure of the components to form a longitudinal or transverse joint.

Fig. 12 shows an embodiment for making the transverse joint liquid-tight, which is ensured by an annular sealing member or a seal with a special profile, which is pressed by means of a suitable rim.

Fig. 13 is a cross-sectional view of the pipeline shown in Fig. 12 showing the sealing member or seal rim.

7731 3

Figure 14 shows a joint in which the components are made of reinforced concrete.

Fig. 15 is a diagram showing the results of stress calculations.

Fig. 16 shows a cross-section of a reinforced concrete hollow structure corresponding to the results of the stress calculation shown in Fig. 15.

Figure 17 shows another embodiment which is particularly suitable for small-sized pipelines.

Figure 18 shows a method of making a liquid-tight connection.

Figure 19 shows the sealing of the joint.

Figure 20 shows another sealing arrangement.

Figure 1 shows in solid line the cross-section of a pipeline 1 manufactured by the method according to the invention and, for comparison, the cross-section of a pipeline 2 with a circular cross-section and the same internal cross-sectional area in broken lines. The pipeline according to the invention comprises five assembled components of the same length.

The two base components 3 are substantially planar; the radius of curvature of the two side components 4 is different at the bottom than at the top; the profile or cross-section of the pipeline is complemented by an exact upper component 5. In the example described, the cross-sectional area of ​​the inner part is e.g. 10 m². The total height H is 2.40 m and the width L is 5.00 m, compared to the diameter D of the corresponding circular pipeline, which is 3.57 m. The trench required for the pipeline according to the invention is wider than the bottom.

7731 3 trench required for a pipeline of circular cross-section, but not so deep; the volume of the trench for the pipeline according to the invention can be smaller overall and the work is easier to perform.

Figure 2 shows another embodiment of a pipeline according to the invention, in which the base components 3a are slightly curved and instead of one component there are two upper components 5a.

Figure 3 shows another embodiment in which a special trough 6 is special along the bottom wall component 3b. The trough 6 is arranged in the middle of the component 3b and is slightly conical so that the components 3b are identical and can be stacked for transport, but other arrangements are also possible. With conventional technology, arranging such a trough brings almost unsolvable problems.

Figure 4 shows a method of connecting two components 4,5 arranged in the same way as components 4a and 5a shown in Figure 2.

In the first step, the component 4 is provided with a connecting plate 7, which can be fastened by means of a weld 8, which in turn can be made at the factory or on the construction site. The plate 7 has enlarged openings 9 which, during installation, are aligned with the enlarged openings 10 of the component 5. During installation, a flexible seal 11 made of elastomer or the like is placed between the component 5 and the plate 7, and then the fastening takes place by means of a screw 12 and a nut 13.

Once a series of components belonging to the next part of the pipeline have been installed, there may be a small relative movement between components 4 and 5, e.g. due to level differences in the trench. Such small movements may be the result of the consolidation of the surrounding land. All these movements are

7731 3 made possible by enlarged openings 9 and 10. Once these movements have ceased, the final joining of the components can be effected by means of the weld 14. The screw 12 and the nut 13 can then be removed and the openings 9 and 10 or only one of them can be closed by means of a weld.

Figure 5 schematically shows a perspective view of a pipeline made by the method according to the invention.

The pipeline comprises longitudinal components A1, BI, CI, etc. for the first part, A'1, B'1, C'1, etc. for the second part, etc. These components are connected to each other by longitudinal joints JL1, JL2, JL3, JL4, etc. and with transverse joints JT1, JT2, JT3, JT4, etc ..

The first step of the method according to the invention comprises calculating the optimal cross-sectional profile of the pipeline in a known manner as a function of known parameters concerning the installation site, the characteristics of the pipeline itself and its operating conditions. The calculations take into account the forces acting on the pipeline, which include:

- own weight of the pipeline,

- weight of liquid passing through the pipeline,

- pressure in the pipeline,

- possible overpressure due to operation of hydraulic equipment, eg valve,

- the hydrostatic pressure of the groundwater in which the pipeline may be installed,

- load due to backfill covering the pipeline,

- any solid overload caused by the filling,

- transient overload caused by the filling,

- temperature and humidity variations,

- reaction forces of support forces, etc.

7731 3

As mentioned at the beginning of the description, it is useful to provide a profile in which the lower part is fairly flat and the upper part corresponds to a curve obtained by means of stress optimization calculations.

The second step comprises dividing the obtained optimum cross-sectional profile into adjacent parts corresponding to the longitudinal components A1, B1, etc., which together form a substantially continuous inner surface, denoted by the letter S in Fig. 5.

The third step comprises determining a transversely variable thickness in at least some of the components to accommodate the components according to the stresses applied to their various points. As shown in Figures 6 and 7, the wall thickness of the pipeline components may vary in the transverse direction. This feature is very important for the manufacture, transport and installation of the components, as the amount and weight of the material as well as the production costs are determined as accurately as possible as a function of the parameters governing the structure of the final pipeline. If the application of the invention to a pipeline for oil, water or the like is considered, it is easy to understand the effect of weight saving on the final profitability of the pipeline.

The pipeline components of the invention can be made of different materials and can be made in different processes, respectively. Thus, it is possible to divide e.g. the production of elements A1, B1, C1, etc. into e.g. the following materials: forging cast iron, spheroidal graphite cast iron, steel, aluminum alloys, etc. With such materials it is possible to use different methods such as casting piece by piece, continuous casting, extrusion, forging , various rolling, etc .. All of these methods allow the recesses and cantilevers to be manufactured in a uniform manner. Said parts are used

7731 3 successive components when installing to make longitudinal and transverse joints as shown below.

It is also possible to use other materials for the pipeline components, e.g. reinforced concrete, fiber-reinforced or unreinforced plastic or resin materials, whereby the elements are made by casting into molds, which also makes it possible to provide the aforementioned recesses and projections.

All methods using the above-mentioned materials require various tools, forging and casting molds, models, etc. to manufacture the pipeline components of the invention, taking into account the features of the pipeline manufacturing method of the invention according to the following conditions:

- the inner surface of the pipeline component to be manufactured shall correspond to the optimal cross-sectional profile of the pipeline determined by calculation as a function of known parameters concerning the method of installation, the operating conditions of the pipeline and its characteristics. The term optimal cross-sectional profile means, under very little changing external conditions, the average cross-sectional profile of a pipeline of a given size;

- each component shall be dimensioned to allow the component to be installed with other components of the pipeline and the different thicknesses of the components shall be calculated to withstand the stresses to which they are subjected.

The final sealing is achieved in a manner depending on the material used. It is achieved from inside the pipeline after final stabilization (settling, expansion compensation, compaction, etc.).

The following describes how the various components are assembled into a pipe 7731 3 by reference to Figures 8 to 12, which illustrate numerous embodiments of longitudinal and transverse joints.

Thus, the cross-section of Figure 8 illustrates the longitudinal connection between the pipeline components A1 and B1. In this case, on the opposite sides of the joint defined by the two surfaces 71 and 72 of the components A1, B1, external longitudinal thickenings 73, 74 are provided, respectively, extending over the entire length of the respective pipeline components A1 and B1. These thickenings may be formed during casting, extrusion or rolling of the corresponding component or may be attached to it by welding, in which case they may be discontinuous. The two thickenings shown in Figure 8 allow for simple and efficient fastening by a U-shaped fastener member 75 together with wedges or spacers 76, 77 which are forcibly fitted in place between the fastener and the corresponding thickener by hammering or the like.

In order to absorb the reaction forces perpendicular to the cross-sectional profile of the pipeline, it is suitable to provide side edges or interfaces to the pipeline component A1, B1, etc. in shapes that allow the best possible duration of their stresses, taking into account parameters of Thus, as non-limiting examples, Figures 8, 9 and 10 show several different cross-sectional profiles of the side edges or boundary surfaces of the pipeline components. In Figure 8, the interfaces 71 and 72 are inclined relative to the perpendicular plane of the cross-sectional profile of the pipeline components. Such a design of the side surfaces of the joint is suitable, for example, when the static loads on the pipeline are predominant.

In Fig. 9, the side edges or pin7731 3 nat 79 and 80 of the pipeline components A1, B1 are rounded in opposite directions so as to absorb the reaction forces in both directions in the perpendicular plane of the cross-sectional profile of the body.

Figure 10 shows stepped side edges or surfaces 82 and 83 that form an overlapping joint or arrangement.

Figure 11 shows cross-sectional profiles 33 and 34 with a pocket that can be filled with a sealing material, for example casting resin.

It should be noted that these side edges or surfaces of the pipeline component can be made by any of the above methods. In order to achieve good liquid tightness in each case, cement mortar, lint, putty, cement, sealing strips or other sealant of natural or synthetic rubber are arranged between the respective side edges or surfaces in the above-mentioned longitudinal joints as number 78 in figure 8, number 81 in figure 9 and number 84 in figure 10 .

In this regard, it should be noted that these joints ensure fluid tightness under pressure.

Figure 14 shows a longitudinal connection arranged between two reinforced concrete components AI, BI of the pipeline. Reference numerals 20 and 21 describe the respective reinforcements of components AI, BI. To provide a connection between these, the reinforcements 20, 21 are allowed to protrude from the components during casting and, when the components are in place at the pipeline construction site, the free ends of the protruding parts are joined together as indicated by 22 and then using a suitable mold, e.g. by anchoring the space 23 is poured into the space in the desired longitudinal motion21

7731 3 to form.

In Fig. 14, the numerals 24 and 25 denote angular shapes and recesses for joining the edges of components A1, B1.

These shapes are intended to facilitate the adhesion of the sealing mortar 23 and also to supplement the fluid tightness of the joint by forming discontinuities to eliminate local leaks. Reference numerals 27 and 28 denote members which hold the mold 26 in place by means of nuts 29, 30.

Figure 12 shows the transverse connection between the components A1, etc. and A1', etc. of two successive parts of the pipeline. Reference numerals 15 and 16 denote the transverse edges or surfaces of the transverse joint. In the illustrated embodiment, the outer circumferential connection is generally indicated by reference numeral 17 and comprises a radial strip arranged in an annular space between the transverse edges or surfaces 15, 16 and an outer circumferential ring having an inner surface against the outer surface of the respective pipeline component. The circumferential ring comprises, along its outer circumferential surface, beveled portions or protrusions 19 which are flattened by the compression of the rim 18A, 18B, as shown in Fig. 13, which is a cross-sectional view of the pipeline shown in Fig. 12. In the embodiment shown in Figure 12, shown as a non-limiting example, the beveled portions or protrusions 19 may be shaped to form a labyrinthine joint. The rim comprises two parts 18A, 18B connected to each other by a tightening member 31, 32 arranged to provide a final tightening.

It should be noted that although screws have not been used in all forms of connection between pipeline components, their use is of course not excluded and flange-like parts can also be used and formed or fastened.

7731 3 pipeline components and then assemble them together using nuts and bolts or similar fasteners.

In some applications, it is possible within the scope of the invention to make pipeline composite structures, some components being made of one material, such as reinforced concrete, in one part of the pipeline, e.g. between the longitudinal joints JL1 and JL4 in Fig. 5, and another component made of another material, e.g. metal or fiber. plastic, in the rest of the pipeline. Such a composite structure can be recommended for water supply in an open ditch without placing a heavy load on the pipeline, in a remote area where it is advantageous to make the lower part of the reinforced concrete on site and make the top of thin prefabricated components and transport them to the site.

Fig. 15 shows a solid line showing a part of a pipeline according to the invention in neutral form (curve I), dashed lines (curve II) the distribution of bending moment due to vertical force and dotted lines (curve III) the distribution of bending moment due to ground lateral forces. The complete calculation also includes the calculation of similar curves with respect to e.g. internal pressure, the own weight of the pipeline, etc. The calculation then involves combining the results of each type of stress.

It can be seen that the entire cross-sectional profile or shape of the section comprises four nodes located at the bottom and top of the pipeline.

Figure 16 shows a cross-sectional half of a pipeline made of four reinforced concrete components.

Il

7731 3

It should be noted that the thicknesses hj, h₂, which are at the maximum stresses shown in Fig. 15, i.e. at the middle and sides of the base, the thickness is 50% greater than the thickness h ^ at the top. The connections between the components JL1, JL2 are located at the nodes. In this figure, the reference describes reinforcing elements embedded in the concrete of the prefabricated components and the reference f₂ describes anchoring members that are bent relative to each other prior to being covered with concrete during structural assembly.

Fig. 17 shows an embodiment intended for relative use ₉ for a small cross-sectional area of ​​about 1.5 to 4 m. For simplicity, the pipeline sections are divided into two components that can be transported separately without special difficulty due to their small size. The lower component 40 is a cast concrete and comprises a flat bottom and sides. In addition, it is found that the sub-component 40 comprises stabilizing members 41 which are formed integrally with it and facilitate installation in a flat-bottomed ditch. The stabilizing members 41 are usually triangular in cross-section with the lower part horizontal. To reduce the weight of the structure, the stabilizing members do not extend the entire length of the component 40. The upper component 42 of the pipeline is simpler in shape, being upside down in the shape of a gutter with a very large radius of curvature. The upper component 42 can be cast or extruded. If the sub-component 40 is extruded, it is common for the stabilizing members 41 to be fixed later, but before the pipeline is installed, by screws, welding or other suitable means.

Fig. 16 shows a stabilizing member 41. This figure reveals the advantage of a second stabilizing member in a casting structure formed of more than two components. Indeed, it can be seen that the side component A2, which is equipped with

7731 3 with the external stabilizing member 41, is itself profitable in its final position. Additional support in connection with the formation of the joint JL2 of the base component Ag is unnecessary.

It should also be noted that when the structure is on the ground, the stabilizing member increases the resistance to lateral forces tending to overturn the structure, which is advantageous in the case of bombs or other shields that can be supported on the ground and subjected to explosive effects.

Fig. 18 shows a method for manufacturing liquid-tight joints in the case where the components are neither weldable nor solderable, when they are made of, for example, concrete.

The edges of each component A1, A2 have corner members 43 of a material to be welded or soldered, e.g. ferrous metal, which is fixed in place during casting, if the component is manufactured in this way. The planar connecting member 44 of ferrous metal or other material to be welded or soldered on the corner member 42 is welded or soldered to the latter, possibly after stabilization on the ground.

Figure 19 shows another installation method of the structure according to the inve ntion.

One of the components A2 comprises a threaded hole 45, which may be provided in the sleeve 46. The threaded hole 45 is oriented approximately perpendicular to the plane of the joint. The second component A1 has a shoulder 47 with a hole 48 in which a threaded fastener 49 is mounted and threaded into the hole 45, with a clearance between the arm and the hole 48 of the fastener 49.

7731 3

Fig. 20 shows another embodiment for making a joint as a liquid seal, in which the concrete components A1, A2 are provided along their inner surfaces with a liquid-tight metal plate cover 50 which forms a permanent shell. The planar inner part 44 is then welded directly to the cover 50, an angular part similar to that shown in Fig. 18 can be arranged on one side of the components A1, A2.

It should be noted that certain arrangements of the above installation are used to install the pipeline and do not per se withstand the hydrostatic pressure in the casing of the pressurized pipeline, because in this case the hydrostatic pressure is partially compensated by the counterforce of the sheath.

In order to better connect the components of the pipeline, shield, etc., and to make it easier to make connections, prestressed cables or rods can be provided in addition to the surrounding cables, connecting longitudinally adjacent longitudinal components. Each of these cables or rods can connect at least two consecutive components. The component can be connected, for example, to the next set of cables or rods and to the previous one with a second set of cables or rods, whereby prestressing can be achieved gradually during the installation process.

Each prestressed cable or rod may also connect three or more of the following components.