WO1999046450A1

WO1999046450A1 - Structure for passage under an embankment

Info

Publication number: WO1999046450A1
Application number: PCT/FR1999/000518
Authority: WO
Inventors: Marcel Matiere
Original assignee: Societe Civile Des Brevets Matiere
Priority date: 1998-03-09
Filing date: 1999-03-08
Publication date: 1999-09-16
Also published as: EP1452646A3; EP1062392B1; ES2257033T3; DK1062392T3; FR2775704B1; CA2322980A1; FR2775704A1; EP1452646A2; MY129555A; EP1062392A1; PT1062392E; JP4644367B2; JP2002506150A; OA11902A

Abstract

The invention concerns a structure for passage under an embankment (12), delimited by a tubular wall (1), comprising, in cross-section transverse to its axis (O), at least three elements, respectively a top element (3) supported by its lateral sides (31, 31') on the upper edges (21) of two side elements (2, 2') having a top part curved towards the axis (O). The invention is characterised in that each top element (3) comprises a wall (30) having a transverse profile with double curvature comprising a central part (33) with slight curvature extended by two end parts (34, 34') each having a common radius of curvature with the upper curved part (24, 24') of the corresponding side element (2, 2') and associated with at least a stiffening rib (32). The invention is particularly useful for building structures with large cross-section for road or railway traffic.

Description

Passage under embankment

The subject of the invention is a work of passage under embankment likely to have a very large section, corresponding in particular to the road gauge, such a work being usable in particular for the passage under embankment of road or rail traffic.

Technical developments, in particular the need to build new traffic routes, such as motorways or high-speed rail lines, have led to more elevated passages. Indeed, a railway line or a highway must have a regular longitudinal profile, without significant ramp and requires, in addition, the elimination of intersections. For some time now, we have therefore had to create traffic lanes on an embankment which equalizes the profile, which requires the construction of numerous works for the passage of secondary traffic lanes, railway lines and rivers.

To solve such problems, the inventor proposed, a few years ago, to make passage works under embankment by a new technique which has many advantages and has experienced great development.

This technique which is described, in particular, in European patents No. 0.081.402 and No. 0.244.890 by the same inventor, consists in producing a tubular wall made up of prefabricated concrete elements which are produced in advance, transported on site when the prefabrication plant is far away, and assembled on the construction site, the assembly then being covered with an embankment. In general, the tubular wall is centered on a longitudinal axis and comprises, in cross section, at least three prefabricated elements, respectively an upper element in an arc of a circle, resting on two side elements separated one from the other and each comprising a base resting on the ground and a side wall having an upper part curved towards the inside of the section so as to connect to the upper element. The previous invention makes it possible to produce very economically structures that can have a very large cross-section corresponding to the road gauge. It has even been possible to carry out, very economically, works covering several lanes of road traffic, for example, for motorways bypassing a city which can advantageously be buried so as to protect the environment.

Of course, it is more economical to use, as much as possible, standard elements, the characteristics and performance of which are known, and, in practice, structures with a semicircular section are usually produced, comprising two side elements having a part upper curved in an arc and connected to an upper element with the same radius of curvature. In the most common embodiment, the upper element covers a circular sector of 90 °, so that the planes of joint between the side elements and the upper element are symmetrically inclined by 45 ° relative to the vertical .

The longitudinal joints are usually made up of simple joints with a horizontal axis and it has been observed that such an arrangement allows to carry out works of very large section and capable of supporting a large load, for example the circulation of a motorway over the structure. However, the use of a semicircular section leads to giving the structure a relatively large height relative to its width since it is equal to about half of the latter. To increase the range between the side elements, the inventor therefore proposed using elements of different radii, the upper element, which still covers an angular sector of 90 °, having a radius larger than the curved parts of the side elements. In this way, the same arrangement of the joints articulated between the elements is kept, but the range between these joints can be increased. However, the deflection of the circular arc is proportional to the distance between supports and, due to the large radius required, the heightening with the key relative to the lateral supports may be too great to use this technique when the difference in height between the background on which the structure is placed and the taxiway passing over it is insufficient. In such a case, passage structures of rectangular section can be made, consisting of a slab resting on two vertical walls, but the prefabrication technique can only be used for reduced passage sections, of the order of 10 to 15 m ² . Indeed, for larger dimensions, prefabricated elements would no longer be manageable and it is then necessary to use the conventional techniques of bridge construction. The object of the invention is therefore to extend the possibilities of application of the technique of construction of engineering structures by prefabricated elements described in the patents cited above from the same inventor, by making it possible to reduce the total height of the work in relation to its scope, while retaining the essential advantages of the prior art.

The invention therefore relates, in general, to an embankment passage structure comprising a tubular wall having a longitudinal axis and consisting of a plurality of concrete elements produced in advance and juxtaposed along longitudinal joints and transverse, said elements being assembled on the construction site so as to form a tubular wall comprising, in cross section with its axis, at least three prefabricated elements, respectively an upper element having two lateral sides parallel to the longitudinal axis and two elements sideways apart from each other and each comprising a base resting on the ground and a side wall having an upper part curved towards the inside of the section, with an upper edge parallel to the longitudinal axis, the element upper resting by its lateral sides along longitudinal joints, on the upper edges of the side elements.

According to the invention, each upper element comprises a cylindrical wall with generation parallel to the longitudinal axis and having a transverse profile with double curvature comprising a central part with small curvature extended by two end parts each having the same radius of curvature as the curved upper part of the side element corresponding, so as to be connected tangentially thereto, said double curvature wall being associated with at least one stiffening rib capable of absorbing the stresses resulting from the self-weight of the upper element and from the load applied by the backfill covering the tubular wall.

The curvature of the central part of the central part of the upper element is determined so that the total height, by the key, of the work, does not exceed a given limit and that the stiffening rib has a moment d sufficient inertia to give the upper member the necessary bending strength, taking into account the distance between the lateral sides and the loads applied.

In a particularly advantageous way, the lateral sides of the upper element and the upper edges of the side elements are provided with conjugate support parts, respectively hollow and projecting, so as to provide two articulated longitudinal joints, the tangential connection of the supporting parts of the upper element with the side elements determining the transmission of the support forces, in each longitudinal joint, in directions inclined with respect to the horizontal, with a horizontal component directed towards the outside.

Preferably, the longitudinal joint plane between the upper edge of a side element and the lateral side of the upper element resting thereon, passes through a common center of curvature and is inclined substantially at 45 ° relative to horizontally. However, the invention will be better understood from the following description of a particular embodiment, given by way of example and shown in the accompanying drawings. Figure 1 shows schematically, in cross section, a structure under embankment according to the invention.

Figure 2 is a detail view of a longitudinal joint. Figure 3 shows a variant.

In Figure 1, there is shown schematically, in cross section, a passage structure according to the invention, comprising a tubular wall 1 disposed on the bottom 11 leveled and packed with a trench 10 and covered with an embankment 12 up to at an upper level 13 located at a height h above the bottom 11 of the trench 10, to allow the passage of a traffic lane above the structure. The tubular wall 1 consists, in general, of prefabricated elements of reinforced or prestressed concrete, which are juxtaposed so as to form successive sections centered on a longitudinal axis O. Such an arrangement has been described in detail, in particular in previous patents EP-0.081.402. and EP-0,244,890 from the same inventor.

In general, each section comprises, in cross section, at least three elements, respectively two side elements 2, 2 'and an upper element 3, having two lateral sides 31, 31', parallel to the longitudinal axis O of the structure, which rest on the upper edges 21, 21 'of the side elements 2, 2'. Each side element 2, 2 ′ comprises a sole 22 forming a base with a flat bottom 22 and a side wall 23 extending upwards, bending inwards at least at its upper part 24. The assembly is balanced so that the prefabricated side element 2 can be placed on the ground and stand by itself without scaffolding, even under the weight of the upper element 3. In the embodiments described in the previous patent EP -0.081.402, the bases of the side elements are connected by a concrete slab which allows the load applied to be distributed over a large area. However, the raft can be removed if the bearing capacity of the bottom 11 of the trench allows it and, in particular, when the span of the structure between the bases of the side elements 2, 2 'is important.

In this case, each side element has the particular shape shown in Figure 1, the sole 22 comprising two wings 22a, 22b extending respectively outward and inwardly of the section, on either side. of the foot of the side wall 23 over a width determined according to the lift of the ground and the stability conditions. Although the wall 23 is curved inwards, experience has shown that such an element can be perfectly stable, even for very large spans.

The structure described in the preceding patent EP-0.081.402 knew a great industrial development because of the many advantages brought by this original technique of realization of structures.

In particular, the passage section is cut, according to patent EP-0.081.402, from so that the longitudinal joints between the elements are placed in areas of constraint nodes whose positions are determined by studying the influence of the applied loads. Thus, it is possible to make elements as large as possible and thus reduce the number of elements making it possible to achieve the desired passage section.

Experience has shown that, in the case of a semicircular arch, these joints could be placed so that the two joint planes between the upper element and each side element are inclined by 45 ° with respect to the horizontal.

Furthermore, it is particularly advantageous to provide articulated joints between each lateral side 31 of the upper element 3 and the upper edge 21 of the associated side element 2. These articulated joints are produced in the manner shown in FIG. 2, the upper edge 21 of the side element 2 being provided with a concave groove 41 while the lateral side 31 of the upper element 3 is provided with a convex edge 42.

This gives great flexibility in construction which facilitates, in particular, the creation of backfill in successive layers because the joints allow slight displacements for the adjustment of the elements. In addition, after commissioning, the stresses applied under the load of the embankment and overloads are transmitted tangentially by arching effect, from the upper element to the side elements which bear laterally on the embankment.

Furthermore, due to the great resistance provided by the judicious positioning of the joints between elements, it is possible to reduce their weight, which facilitates their handling even for very large dimensions.

In the embodiments described in patent EP-0.081.402, the tubular wall of the structure has a semicircular section symbolized by the dotted line SI in FIG. 1. It can be seen that the height of the structure, at the key is equal to half the span between supports. The rectangular gauge for passage in such a structure, for example for a road traffic lane, therefore has a height of the order of half the width.

As indicated, to reduce the height of the structure relative to its width, it is possible to give the upper element a radius of curvature greater than that of the side elements to which it is tangentially connected, according to the profile S2 indicated in dotted lines in FIG. 1. In this case, the passage gauge G shown in phantom in the figure has a width L greater than twice the height H. However, the overall height hl of the key structure remains quite large and may be too high when the difference in height h between the upper level of the taxiway 13 passing over the structure and the bottom 11 thereof is reduced.

The invention provides a solution to this problem while retaining, however, most of the advantages of the previously known arrangement.

As shown, in fact, in Figure 1, the structure according to the invention comprises, in cross section with its axis 0, an upper element 3 resting by its lateral sides 31, 31 'on the upper edges 21, 21' of two side elements 2, 2 'which can be perfectly identical to the side elements used in previously known structures.

Each side element 2 therefore comprises, as in the previous arrangements, a side wall 23 of which at least the upper part 24 is curved so as to form a circular sector centered at a point Ol and which extends vertically from a sole-shaped base comprising two wings, respectively external 22a and internal 22b resistant to the overturning of the element 2 inwards or outwards.

The upper element 3 has, however, a particular shape. It consists, in fact, of a curved wall 30 associated with a stiffening rib 32. The wall 30 has a cylindrical shape with generatrices parallel to the longitudinal axis 0 and having a double curvature. It comprises, in fact, a central part 33 with a very large radius of curvature which is connected to two end parts 34, 34 'having a radius of curvature equal to that of the curved upper part of the side wall 23, 23' of the 'associated side element 2, 2'. The two parts 34 and 24 are therefore centered at the same point 01, O'I and extend, respectively, on either side of the joint plane P.

The central part 33 with a large radius of curvature can even be planar, as in the embodiment of FIG. 1, and is progressively connected to the end parts 34, 34 ′ centered at 01, O'I. The height e of the rib 32 is determined so as to give the assembly a sufficient moment of inertia to withstand the forces applied to the part 33 of the element 3. Preferably, the elements are dimensioned so that the longitudinal supports are spaced apart by a width L and placed at a height H above the bottom 11, these dimensions corresponding to the desired clearance gauge G. The seals 4, 4 'are then placed at the corners of this template.

The upper element 3 can be calculated as a beam with variable section resting on two articulated supports constituted by the longitudinal joints 4, 4 'formed on the upper edges 21, 21' of the side elements 2, 2 '. The height e is therefore not greater than that of a flat deck resting on two vertical abutments, in order to limit the same size.

On the other hand, the particular shape of the end parts 34, 34 ′ of the upper element 3 makes it possible to retain the advantages of the structure previously known.

For example, as shown in FIG. 2, the articulated joint 4 can be produced in the same way, the joint plane P preferably being inclined relative to the horizontal, by an angle A equal to 45 °. We know that, in practice, this type of joint has given the best results, even for very large spans. In addition, the tangential connection of the elements by parts 24 and 34 of the same radius of curvature makes it possible to ensure the continuous transmission of forces by arching effect and to retain a certain flexibility of the structure which is particularly useful for resisting differential settlement and, even, to earthquakes, as we have been able to verify.

In particular, the forces applied to the two articulated joints 4, 4 ′ have a component horizontal tending to push outwards the side elements 2, 2 'which bear on the side embankments, the latter being made so as to participate in the strength of the structure. On the other hand, the inwardly curved shape of the side elements 2, 2 'and the possibility of giving them a very small thickness with respect to their length gives the assembly a certain flexibility making it possible to mobilize the embankments. It appears that the total height H 'of the structure is not appreciably greater than that of a structure of rectangular section and therefore allows the passage of a traffic lane 13 at a fairly reduced height H above the bottom 11 of the trench 10, the upper element 3 can be covered with a thin layer of fill.

It should be noted that the particular shape of the upper element makes it possible to reduce the effects of settlement which normally occur at the edge of a flat deck and which lead to degradation of the roadway. Indeed, since the central part 33 is extended by parts 34 of greater curvature, the thickness of the fill gradually increases until the lateral supports 4, 4 'which are further from the upper surface 13 and, due of the continuity of the circular external wall, this gradual increase or decrease in the height of the embankment above the concrete wall ensures better absorption of the threshold effect when the structure passes.

Of course, the invention is not limited to the details of the embodiment which has just been described and which could be the subject of variants or improvements without departing from the protective framework defined by the claims.

In particular, to produce the upper element 33, it is possible to use the usual techniques of reinforced concrete, in particular prestressing, so as to reduce the height of the stiffening rib. We can also increase the number of ribs associated with each element.

Furthermore, in the embodiment of FIG. 1, the side elements 2, 2 ′ have a center of curvature 01 placed at the level of the bottom 11, so as to increase the height of the curved part 24 for a given ratio of the width L to the height H of the template. One could, however, give another shape to the side elements, as shown, for example, in Figure 3. Generally speaking, in fact, the height e of the rib must be just sufficient to give the upper element 3 the necessary resistance to bending while ensuring the desired clearance gauge.

In addition, as described in the patent EP-

0.081.402, the internal edges of the bases 22, 22 'of the side elements can be connected by a concrete slab allowing the load to be distributed over a large area.

The reference signs inserted after the technical characteristics mentioned in the claims have the sole purpose of facilitating the understanding of the latter and in no way limit their scope.

Claims

CLAIMS 1. Passage structure under an embankment (12), comprising a tubular wall (1) having a longitudinal axis (O) and consisting of a plurality of concrete elements produced in advance and juxtaposed along longitudinal joints and transverse, said elements being assembled on the construction site so as to form a tubular wall (1) comprising, in cross section with its axis, at least three prefabricated elements, respectively an upper element (3) having two lateral sides (31 , 31 ') parallel to the longitudinal axis (O) and two side elements (2, 2') spaced from each other and each comprising a base (22) resting on the ground (11) and a wall lateral (23) having an upper part (29) curved towards the inside of the section, with an upper edge (21) parallel to the longitudinal axis (O), the upper element (3) resting by its lateral sides ( 31, 31 '), along longitudinal joints (4, 4'), on the he upper edges (21, 21 ') of the side elements (2, 2'), characterized in that each upper element (3) comprises a wall (30) having a transverse profile with double curvature comprising a central part (33 ) with a small curvature extended by two end parts (34, 34 ') each having the same radius of curvature as the curved upper part (24, 24') of the corresponding side element (2, 2 '), so as to be connect tangentially thereto, said double curvature wall (30) being associated with at least one stiffening rib (32) capable of absorbing the stresses resulting from the self-weight of the upper element (3) and from the loads applied by the embankment (12) covering the tubular wall (1).

2. Embankment structure according to claim 1, characterized in that the curvature of the central part (33) of the upper element (3) is determined so that the total height, as a result, of the structure , does not exceed a given limit and that the stiffening rib (32) has a sufficient moment of inertia to give the upper element (3) the necessary resistance to bending, taking into account the distance between the lateral sides ( 31, 31 '), to support the applied loads.

3. Embankment structure according to one of the preceding claims, characterized in that the lateral sides (31, 31 ') of the upper element (3) and the upper edges (21, 21') of the side elements ( 2, 2 ') are provided with conjugate support parts, respectively hollow and projecting, so as to provide two articulated longitudinal joints (4, 4'), the tangential connection of the support parts of the upper element (3 ) with the side elements (2, 2 ') determining the transmission of the support forces, in each longitudinal joint, in directions inclined relative to the horizontal, with a horizontal component directed towards the outside.

4. Embankment structure according to one of the preceding claims, characterized in that the longitudinal joint plane between the upper edge of a side element and the lateral side of the upper element resting thereon passes by a common center of curvature and is inclined substantially at 45 ° relative to the horizontal.

5. Embankment structure according to one of the preceding claims, capable of providing a rectangular passage template (G) having a height (H) and a width (L), characterized in that the dimensions of the elements are determined so that, after installation, the longitudinal joints (4, 4 ') between the elements are placed substantially at the upper corners of the clearance template (G), the stiffening ribs (32) of the upper elements (3) having a lower face placed at a level corresponding substantially to the height (H) of the template (G) and the longitudinal joints (4, 4 ') being spaced apart by a distance corresponding substantially to the width (L) of the template (G).