ES2257033T3 - STEP STRUCTURE UNDER A TERRAPLEN. - Google Patents

Abstract

Passage structure under an embankment (12) comprising a tubular wall (1) having a longitudinal axis (O) and which is constituted by a plurality of concrete elements made beforehand and juxtaposed along longitudinal and transverse joints, said elements being assembled at the construction site in order to form a tubular wall (1) comprising, in cross section to its axis, at least three prefabricated elements, respectively an upper element (3) with two lateral sides (31, 31 '') parallel to the longitudinal axis (O) and two lateral elements (2, 2 '') separated from each other and each comprising a base (22) that rests on the ground (11) and a side wall (23) with 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 on its lateral sides (31, 31``), a along the longitudinal joints (4, 4``), on l The upper edges (21, 21 '') of the lateral elements (2, 2 ''), characterized in that each upper element (3) comprises a wall (30) with a double curvature transverse profile comprising a flat central part ( 33) extended by two end parts (34, 34 '') each presenting the same radius of curvature as the curved upper part (24, 24 '') of the corresponding side element (2, 2 ''), with the object of tangentially joining it, said double curvature wall (30) associated with at least one reinforcement rib (32) capable of absorbing the stresses resulting from the weight of the upper element (3) and the loads applied by the embankment ( 12) covering the tubular wall (1), and because the dimensions of the elements are determined such that the total height (h '') of the structure is not substantially greater than that of a rectangular section structure that limits a same clearance gauge (G) and that the height (e) of the rib ura does not exceed that of a flat table that limits said gauge, the height of the rib (32) being determined to provide the upper element with a moment of inertia sufficient to withstand the stresses applied in the central part (33) of the element upper (3).

Description

Passage structure under an embankment.

The present invention relates to a structure passing under an embankment that can present a very section wide, which corresponds remarkably to the gauge of the road, being able to said structure be used in particular for the passage under the embankment of a road or rail traffic.

Technical evolution, in particular the need of building new roads, such as highways or high-speed rail lines, involves the multiplication of overpasses Indeed, a railway line or a highway they must present a regular grade, without significant ramps and It also requires the elimination of intersections.

For some time the traffic lanes have been built on an embankment that matches the profile, which it requires the construction of numerous structures for the passage of secondary roads, rail lines and the rivers.

To solve these problems, the inventor has proposed, some years ago, to make structures under the embankment thanks to a new technique that presents numerous advantages and has known an important development.

This technique, described in particular in the European patents No. 0 081 402 and No. 0 244 890 and No. 0 296 013 of same inventor, consist of making a tubular wall constituted by precast concrete elements made beforehand, transported to the site if the prefabrication plant is far away, and assembled at the construction site, being the whole then covered by an embankment.

In general, the tubular wall is centered on a longitudinal axis and comprises, in cross section, at least three prefabricated elements, respectively a superior element in the form of a circle arc, which rests on two elements sides separated between them and each comprising a base which rests on the ground and a side wall with a part upper curve towards the inside of the section in order to Connect with the upper element.

The previous invention allows to realize fairly economic structures that can present a section of very wide passage that corresponds to the gauge of the track. It has even been possible to make, in an economic way, structures that cover several roadways, for example, for highways beltway of a city that can be buried advantageously to protect the environment.

European Patent No. 0 585 959 also describes a buried conduit comprising, in cross section, a upper element in arc of circle or, eventually, in handle of basket, which is supported by joints on two prefabricated support elements.

It is obviously cheaper to use in the as much as possible, standard elements whose characteristics and benefits are known and, in practice, are performed normally some structures with semicircular section, which they comprise two lateral elements that have an upper part curved in an arc of circle and joining a higher element with The same radius of curvature. In the most common embodiment, the upper element covers a circular sector of 90º, so that the joint planes between the side elements and the element upper are inclined symmetrically at 45 ° with respect to the vertical.

The longitudinal joints are constituted normally by simple horizontal axis joints and it has noted that such an arrangement allowed for some large section structures that can withstand a load important, for example the movement of a road above the structure.

However, the use of a section semicircular implies imparting a height to the structure relatively important with respect to its width since it is equal to about half of it.

To increase the surface between the elements side, the inventor has therefore proposed to use some elements of different radii, presenting the upper element, which also covers an angular sector of 90º, a radius greater than the curved parts of the side elements. In such a way, it retains the same arrangement of articulated joints between elements but the surface between these joints can increase However, the arrow of the circular arc is provide the distance between the support and, since it is required  a large radius, the elevation in the key with respect to the supports laterals may be too important to use this technique when the height difference between the bottom in which it is placed the structure and the road that passes over it is insufficient.

In that case, the structures can be made of rectangular section passage constituted by a slab that It supports two vertical walls, but the prefabrication technique It can only be used for reduced-pass sections of the order of 10 to 15 m2. For larger sizes, the elements Prefabricated would not be easy to handle and should be used Classic bridge construction techniques.

The invention therefore aims at extend the application possibilities of the engineering technique civil by prefabricated elements described in the patents mentioned above of the same inventor, allowing to reduce the total height of the structure with respect to its surface, while retaining the essential advantages of the technique previous.

The present invention is therefore referred to in general terms, to a passage structure under an embankment, which it comprises a tubular wall with a longitudinal axis and constituted by a plurality of concrete elements made beforehand and juxtaposed along longitudinal and transverse joints, said elements being assembled at the construction site to form a tubular wall comprising, in cross section to its axis, at least three prefabricated elements, respectively a upper element with two lateral sides parallel to the axis longitudinal and two lateral elements separated from each other, each comprising a base that rests on the floor and a wall side that presents a curved upper part inwards of the section, with an upper edge parallel to the longitudinal axis, the upper element resting on its lateral sides along of longitudinal joints, on the upper edges of the lateral elements.

According to the invention, each element upper comprises a cylindrical wall of generatrices parallel to the longitudinal axis and has a double curvature cross profile comprising a flat central part extended by two parts extremes each presenting the same radius of curvature as the curved upper part of the corresponding side element, of so that they join tangentially to it, said wall being double curvature associated with at least one reinforcement rib liable to absorb the stresses resulting from the weight itself of the upper element and the load applied by the embankment that Cover the tubular wall.

The double curvature of the central part of the top element and the dimensions of the elements are such that the total height of the structure does not substantially exceed that of a rectangular section structure that limits the same gauge, not exceeding the height of the rib of a flat board that limit the gauge, presenting the reinforcement rib a moment of sufficient inertia to confer resistance to the upper element necessary to flexion, taking into account the distance between lateral sides and applied loads.

Particularly advantageously, the sides sides of the upper element and the upper edges of the lateral elements are provided with conjugate support parts, in hollow and in highlight respectively, in order to perform two articulated longitudinal joints, determining the tangential joint of the supported parts of the upper element with the elements lateral transmission of support voltages, at each joint longitudinal, according to inclined directions with respect to the horizontal, with a horizontal component directed towards the Exterior.

Preferably, the longitudinal joint plane between the upper edge of a lateral element and the lateral side of the upper element that rests on it passes through a common center of curvature and is substantially inclined at 45 ° with respect to the
horizontal.

But the invention will become more clearly than manifest from the following description in a way of particular embodiment, provided by way of example and represented in the attached drawings.

Figure 1 shows schematically, in section transverse, a structure under an embankment according to the invention.

Figure 2 is a detailed view of a joint longitudinal.

Figure 3 shows a variant.

In figure 1, it has been represented schematically, in cross section, a passage structure of according to the invention, which comprises a tubular wall 1 arranged on the bottom 11 flattened and rammed of a ditch 10 and covered by an embankment 12 to a higher level 13 that is located at a height h above the bottom 11 of the trench 10, to allow the passage of a traffic route above the structure.

The tubular wall 1 is generally constituted by precast reinforced or prestressed concrete elements, juxtaposed to form successive sections centered on an axis horizontal O.

This provision 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 includes, in section transversal, at least three elements, respectively two elements lateral 2, 2 'and an upper element 3, which has two sides laterals 31, 31 ', parallel to the longitudinal axis O of the structure, that rest on the upper edges 21, 21 'of the elements 2, 2 'sides.

Each lateral element 2, 2 'comprises a solera 22 forming a base with flat bottom 22 and a side wall 23 that extends upward, curving inwards at least in its upper part 24. The set is balanced in such a way that the prefabricated side element 2 can be placed on the floor and stand alone without the need for 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 lateral elements they are joined by means of a concrete pillar, which allows spread the load applied over a large area. But nevertheless, the concrete pillar can be suppressed if the lift of the bottom 11 of the trench allows it and, in particular, when the surface of the structure between the bases of the elements lateral 2, 2 'is significant.

In this case, each side element presents the particular shape represented in figure 1, comprising the solera 22 two wings 22a, 22b respectively extending towards the outside and inward of the section, on both sides of the foot of the side wall 23 over a given width as a function of soil support and stability properties. Although the wall 23 is curved inwards, the experience has shown that said element could be perfectly stable, even for very large surfaces.

The structure described in the previous patent EP 0.081.402 has known a very important industrial development due to to the numerous advantages provided by this original technique of realization of civil engineering structures.

In particular, the trimming of the step section is carried out, in accordance with EP 0 081 402, of such so that the longitudinal joints between the elements are found in areas of tension nodes whose positions are determined by studying the influence of applied loads. So, items as large as possible can be made and decrease the number of elements that allow the section of desired step.

Experience has shown that, in the case of a semicircular vault, these joints could be placed in such a way that both joint planes between the upper element and each element lateral have an inclination of 45º with respect to the horizontal.

On the other hand, it is particularly advantageous offer articulated joints between each side 31 of the upper element 3 and upper edge 21 of the lateral element Associate 2. These articulated joints are made as depicted in figure 2, the upper edge 21 of the side element 2 being provided with a concave groove 41 while the side 31 of the upper element 3 is provided with a convex edge 42.

This gives great flexibility of construction and facilitates in particular the completion of the embankment through successive layers since the joints allow slight displacements to adjust the elements. Also after of commissioning, the voltages applied under the load of the embankment and overloads are transmitted tangentially by a vault effect, from the upper element to the element lateral that rest laterally on the embankment.

Moreover, due to the high resistance provided by proper placement of the joints between the elements, it is possible to reduce its weight, which facilitates its handling, Even for very large sizes.

In the embodiments described in the EP 0 081 402, the tubular wall of the structure has a semicircular section symbolized by the dotted line S1 in the Figure 1. It can be seen that the structure, in the key, is the same at half the surface between supports. The rectangular gauge of step in such a structure, for example for a way of circulation, therefore has a height of the order of half of the width.

As indicated, in order to reduce the height of the structure with respect to its width, it is possible provide the upper element with a radius of curvature greater than the of the lateral elements to which it joins tangentially, according to the profile S2 illustrated as a dotted line in figure 1. In in this case, the gauge G of passage represented in mixed strokes in the Figure shows a width L greater than twice the height H. Without However, the overall height h1 of the structure in the key follows being relatively important and can be too big when the height difference h between the upper level of the track circulation 13 that passes over the structure and bottom 11 of This one is reduced.

To reduce the total height of the structure, has also proposed, in French Patent No. 2 642 109, replace the curved upper element with a simple flat slab that rests, by means of joints, on the upper edges of the lateral elements.

However, the effects of tamping on the flat board limit determine a threshold effect that causes a degradation of the circulation path that passes over the structure.

The invention offers a solution to this problem. while retaining the essential of the advantages of the arrangement known above.

Indeed, as shown in Figure 1, the structure according to the present invention comprises, in section transverse to its axis O, an upper element 3 that rests with its lateral sides 31, 31 'at the upper edges 21, 21' of two 2, 2 'side elements that can be perfectly identical to the side elements used in known structures previously.

Each lateral element 2 therefore comprises, as in the preceding provisions, a side wall 23 of which at minus the upper part 24 is curved in order to form a circular sector centered on an O1 point and extending vertically from a base in the form of a hearth comprising two wings, respectively, external 22a and internal 22b, which resist the tensions of element 2 inwards or towards the Exterior.

The upper element 3 presents, by the Otherwise, a particular way. In effect, it consists of a curved wall 30 associated with a reinforcement rib 32. The wall 30 has a cylindrical shape with generatrices parallel to the axis longitudinal O and with a double curvature. It includes a part flat central 33 that joins two end parts 34, 34 'that they have a radius of curvature equal to that of the upper part curved of the side wall 23, 23 'of the associated side element 2, 2'. Both parts 34 and 24 are therefore centered on the same point O1, O'1 and extend, respectively, on both sides of the joint plane P.

The height e of the rib 32 is determined in order to give the whole a moment of inertia enough to withstand the loads applied in part 33 of the item 3.

Preferably, the elements are sized so that the longitudinal supports are separated in a width L and arranged at a height H above of bottom 11, these sizes corresponding to the desired gauge G. The joints 4, 4 'are then arranged at the angles of this gauge.

The upper element 3 can be calculated as a variable section beam that rests on two articulated supports constituted by the longitudinal joints 4, 4 'practiced in the upper edges 21, 21 'of the lateral elements 2, 2'. The height e is therefore not greater than that of a flat plate that it relies on two vertical buttresses, to limit it gauge.

On the contrary, the particular form of extreme parts 34, 34 'of the upper element 3 allows to keep the advantages of the structure known above.

For example, as shown in Figure 2, the articulated joint 4 can be made in the same way, being the joint plane P, preferably inclined with respect to the horizontal, with an angle A equal to 45º. It is known that, in the practice, this type of board has given the best results, even for very large surfaces.

In addition, the tangential connection of the elements to through parts 24 and 34 of the same radius of curvature allows ensure the continuous transmission of efforts by the effect of vault and retain some flexibility of the structure particularly useful for resisting differential ramming, and even, seismic shocks, as has been verified.

In particular, the tensions applied to both articulated joints, 4, 4 'have a horizontal component that tends to push out the side elements 2, 2 ', that rely on the lateral embankments, the latter being made in order to share the resistance of the structure. Moreover, the inwardly curved shape of the lateral elements 2, 2 'and the possibility of providing them with a very small thickness with respect to its length offers the whole a certain flexibility that allows the earthworks to be mobilized.

It seems that the total height h 'of the structure does not is substantially superior to that of a section structure rectangular and therefore allows the passage of a traffic lane 13 at a height h quite reduced above the bottom 11 of the trench 10, the upper element 3 being able to be covered by a thin layer of embankment.

It should be noted that the particular form of the upper element allows the reduction of tamping effects that occur normally at the limit of a flat board and that cause degradation of the road. Indeed, since the central part 33 is extended by curvature parts 34 greater, the thickness of the embankment gradually increases to lateral supports 4, 4 'that are at a greater distance from the upper surface 13 and, due to the continuity of the wall external circular, said progressive increase or decrease of the height of the embankment above the concrete wall ensures a better absorption of the threshold effect in the passage of structure.

Obviously, the invention is not limited to details of the embodiment that has just been described and could be the object of variants or improvements without depart from the protection framework defined by the claims.

In particular, to perform the upper element 33, conventional reinforced concrete techniques can be used, especially prestressing, in order to reduce the height of the reinforcement rib. You can also increase the number of ribs associated with each element.

On the other hand, in the embodiment of the Figure 1, the lateral elements 2, 2 'have a center of curvature O1 arranged at the bottom 11, in order to increase the height of the curved part 24 for a given relationship between the width L and height H of the gauge.

However, it could be given to the elements sideways another shape, as shown, for example, in figure 3. In general, the height e of the rib should be sufficient to provide the upper element 3 with flexural strength necessary ensuring the desired gauge.

In addition, as described in the patent EP 0.081.402, the inner edges of the bases 22, 22 'of the lateral elements can be joined by a concrete pillar that allows to distribute the load over a large area.

The reference signs inserted after the technical characteristics mentioned in the claims, They are solely intended to facilitate the understanding of these latest and in no way limit its scope.

Claims (4)

1. Passage structure under an embankment (12) that it comprises a tubular wall (1) having a longitudinal axis (O) and that is constituted by a plurality of concrete elements made in advance and juxtaposed along boards longitudinal and transverse, said elements being assembled at the construction site in order to form a wall tubular (1) comprising, in cross section to its axis, at least three prefabricated elements, respectively a superior element (3) with two lateral sides (31, 31 ') parallel to the longitudinal axis (O) and two lateral elements (2, 2 ') separated between them and each comprising a base (22) that rests on the ground (11) and a side wall (23) with a curved upper part (29) towards the inside of the section, with an upper edge (21) parallel to the longitudinal axis (O), the upper element (3) resting on its lateral sides (31, 31 '), along the longitudinal joints (4, 4 '), on the upper edges (21, 21') of the elements lateral (2, 2 '), characterized in that each upper element (3) comprises a wall (30) with a double curvature transverse profile comprising a flat central part (33) extended by two end parts (34, 34 ') each having the same radius of curvature that the curved upper part (24, 24 ') of the corresponding lateral element (2, 2'), in order to tangentially join to it, said double curvature wall (30) being associated at least with a reinforcement rib (32) liable to absorb the stresses that result from the weight of the upper element (3) and the loads applied by the embankment (12) that cover the tubular wall (1), and because the dimensions of the elements are determined in such a way that the total height (h ') of the structure is not substantially greater than that of a rectangular section structure that limits the same passage gauge (G) and that the height (e) of the rib is not greater than that of a flat board that limits that gauge, if endo the height of the rib (32) determined so as to provide the upper element with a moment of inertia sufficient to withstand the stresses applied in the central part (33) of the upper element (3). 2. Structure under an embankment according to claim 1, characterized in that the lateral sides (31, 31 ') of the upper element (3) and the upper edges (21, 21') of the lateral elements (2, 2 ') are provided of conjugate support parts, respectively in hollow and in projection, so as to realize articulated longitudinal joints (4, 4 '), determining the tangential union of the support parts of the upper element (3) with the lateral elements (2, 2 ') the transmission of the support tensions, in each longitudinal joint, according to inclined directions with respect to the horizontal, with a horizontal component directed towards the outside. 3. Structure under an embankment according to one of the preceding claims, characterized in that the longitudinal joint plane between the upper edge of a lateral element and the lateral edge of the upper element supported on it passes through a common center of curvature and is inclined substantially at 45 ° with respect to the horizontal. 4. Structure under an embankment according to one of the preceding claims, capable of providing a rectangular gauge (G) having a height (H) and a width (L), characterized in that the dimensions of the elements are determined such that, after placement, the longitudinal joints (4, 4 ') between the elements are substantially at the upper angles of the passage gauge (G), the reinforcement ribs (32) of the upper elements (3) having a lower face arranged at a level that substantially corresponds to the height (H) of the gauge (G) and the longitudinal joints (4, 4 ') being separated by a distance that substantially corresponds to the width (L) of the gauge (G).