EP0784726A1

EP0784726A1 - Beam structure and constructions using same

Info

Publication number: EP0784726A1
Application number: EP96924940A
Authority: EP
Inventors: Edmond Balzer; Philippe Balzer
Original assignee: Balzer Anne-Marie
Current assignee: Balzer Anne-Marie
Priority date: 1995-07-06
Filing date: 1996-07-05
Publication date: 1997-07-23
Also published as: US6101781A; FR2736372B1; AU6522196A; FR2736372A1; WO1997002392A1

Abstract

A beam structure designed to be subjected to at least one bending load defining therealong an envelope curve of bending moments (C1, C2) comprising at least one first portion in which the bending moments are of a first sign, at least one second portion in which the bending moments are of a second sign opposite to the first, and at least one third portion in which the bending moments are of the first sign or the second sign or are zero. The beam structure includes a first body (11) whose height and length are also those of the beam structure, and a second body (13) joined sideways to the first body (11) along the full length thereof. The second body (13) is at the top of the first body (11) in the first portion of the envelope curve of bending moments and at the bottom of the first body (11) in the second portion of said curve, whereas in the third portion of the envelope curve of bending moments, said second body (13) is longitudinally continuous and arranged in a variable intermediate position between the top and bottom of said first body (11).

Description

BEAM STRUCTURE AND ARTICLES USING THE SAME

The present invention relates to beam structures intended to be subjected to at least one bending force determining along said beam structure a curve at least bending moments, comprising in particular concrete, a first body whose height and length respectively define the height and the length of said beam structure. The technical fields concerned by the invention include civil engineering, in particular engineering structures and hydraulic structures, building, and more broadly any field requiring the use of bending resistant structures, made of concrete or other material. known moldable.

The prior art teaches numerous works in concrete or in prestressed concrete, whether or not bearing a metal frame. For example, structures of the frame bridge type as shown in FIG. 1A are known, or structures of the multi-beam bridge type connected together by a slab as shown in FIG. 2A, or structures of the bridge type with masts and shrouds as shown in Figure 3 A.

The dimensions of these structures and beams that make up if necessary, are particularly determined by ^'strains to which they are submitted at fonction¬ ment, including their own weight and variable or permanent overloads applied, allowing the déteπniner bending moment curve relating to the structure or to a beam making up this structure.

For each example of structure given in Figures IA, 2 A, and 3 A, there is shown in Figures IB, 2B, and 3B respectively one or the curves representative of the corresponding bending moments by part of the structure, by example a curve for the deck and a curve for the abutment in the case of the structure shown in Figure 3 A. In a simplification, variable overloads have not been taken into account in the moment curves bending relative to Figures IA, 2A, and 3 A. In the whole of the present memo, for the sake of simplification and better understanding, the abscissa axis of any bending moment curve has been represented in a direction identical to that of the part of the work to which it relates, the value 0 of the bending moments on the ordinate axis having been positioned on the abscissa axis, and the bending moments have been assigned an identical sign in. for the same sense of effort, that is to say essentially positive between supports and negative or zero at supports or around them.

In FIG. 1B, the four curves 1 ′, 2 ′, 3 ′, 4 ′ of the bending moments corresponding to the four walls 1, 2, 3, 4 making up the frame bridge with constant section shown in FIG. IA. It is noted for the upper wall 1 for example that the bending moments on the curve 1 'are maximum in absolute value and of sign opposite to the supports and in the central part of the wall most distant from the supports. The bending moment curve 1 ′, which allows the calculation of the bending stresses which the wall 1 must resist, results in a distribution of the main metal reinforcements as follows: in the outer part of the frame in the area of the supports, and in the lower part of the wall 1 in the central zone furthest from the supports, the metal reinforcements being distributed in the stretched parts of a section of concrete due to poor resistance to the latter's traction. The same reason can be applied to the horizontal wall 3 and to the vertical walls 2 and 4 making up the frame bridge, causing a distribution of the main metal reinforcements as shown in Figure IC.

The example shown in Figure IA shows a simple design work but whose resistance comes essentially from the metal reinforcements placed mainly in the tense areas of the work. This type of structure in fact comprises a large quantity of concrete which does not enter into the strength of the structure, and whose sole objective is to coat the metal reinforcements, thus resulting in relatively high additional costs.

The work shown in FIGS. 2A and 2C shows a bridge deck of the multiple beam type connected together by a slab, resting on two abutments and a central stack by means of simple supports, and comprising this makes two spans. The bending moment curve for the deck is shown in Figure 2B. Each beam forms with the part of the slab which it supports a T-shaped cross-section structure very well in spans via the slab working in compression, but relatively weakly resistant in continuous support, in this case on the support central where the slabs are stretched. Such a configuration makes it necessary to size the beams with respect to the compressive strength required in the central support area, such beams then having unnecessary dimensions in areas between supports, or with extreme simple supports at the level of cu¬ lées where the bending moment is zero. Consequently, such a structure notably includes a large quantity of useless concrete which hardly enters into the calculation of the strength of the structure and which moreover requires oversizing the resistant parts of the structure because of its weight.

The structure shown in Figure 3A shows a cable-stayed type bridge, the deck of which rests at one of its ends on an embankment by means of a simple support, partially central on a pier, and at its other end on a abutment by means of a cased support. The two spans thus formed are guyed at their centers. The curves of the bending moment relative to the deck and the abutment are shown in Figure 3B. The re¬ marks formulated with regard to the preceding examples remain valid for the example of FIG. 3A, the effect of the shrouds being comparable to continuous supports.

The prior art also teaches bridge structures with beams with variable moment of inertia, in particular beams whose height is large nearby, continuous supports on the piers for example, in order to increase the moment of inertia of the section of concrete working in the compression zones, and small in the central part of the span in the tense zones. Such structures which allow concrete work in compression in the major part of the cross sections of the beams, however require a large amount of concrete in the area of the continuous supports, and a significant height of work in this zoned.

The prior art also teaches prestressed or post-stressed concrete structures, the objective of which is to remove the tensioned parts of the cross sections by the tension of cables having the effect of rejecting the neutral axis outside the cross section. It will be noted that these techniques which make it possible to work the concrete only in compression and therefore cause a reduction in the weight of the concrete used with equal work resistance compared to the reinforced concrete technique, are very expensive by in relation to the latter and therefore only used in works of relative importance.

The main objective of the present invention is to overcome the aforementioned drawbacks. When considering the example shown in Figures 2A and 2C which shows a structure comprising a plurality of T-section beams as explained above, the applicant has observed that, with respect to the curve of the bending moments d 'a beam, the horizontal part of the T of the beam should ideally be placed in the upper part of the beam between supports, when the bending moment given by the curve is maximum, and ideally placed in the lower part of the beam in the area continuous central support when the bending moment given by the curve is of opposite sign and maximum in absolute value, so that the horizontal portion of the T is positioned in the compressed area of the cross sections of the beam. Between the two extreme positions mentioned above, the horizontal part of the T can adopt intermediate positions depending on the curve of the bending moments.

More specifically, the present invention consists of a beam structure intended to be subjected to at least one bending force determining along said beam structure a curve enveloping the bending moments which comprises at least a first part in which the bending moments are of the same first sign, at least a second part in which the bending moments are of the same second sign opposite to said first sign, and at least a third part in which the bending moments can be of said first sign or of said second sign or zero, said beam structure comprising in particular concrete, at least one first body, the height and length of which respectively define the height and the length of said beam structure, characterized in that said beam structure comprises a second body laterally connected to said first body along the length of said first body, said second body being placed at an upper end of the height of said first body in the first part of said curve envelopes bending moments, said second body being placed at a lower end of the height of said first body in second part of said curve envelopes bending moments, and in that said second body is continuous longitudinally and placed in a variable position over the height of said first body, from said high end to said bottom end in the third part of said envelope curve bending moments.

Determination of the bending moment curve or the envelope curve of bending moments applicable to the beam structure according to the invention makes it possible to know the extreme values of the latter as well as their axial positions on the beam structure. Thus, the position of the second body in height with respect to the first body will be a function of the moments bending along the length of the beam structure so that the second body is positioned in the compressed area of a cross section of the beam structure. More particularly, when the positive and negative bending moments are maximum or close to the maximum in absolute value respectively, the second body will be in the extreme position relative to the height of the first body, that is to say in the upper or lower part of the latter as will be explained later with the help of the appended figures. When the bending moment is low in absolute or zero value, the second body adopts for example an average intermediate position, the bending stresses in this case being low or zero. Finally, the second body will advantageously adopt a continuous profile, along the beam structure, connecting the various extreme and intermediate positions. The beam structure according to the invention allows an optimized positioning of the concrete working in compression, in any cross section of the beam structure, and therefore allows a considerable reduction in weight of concrete compared to a beam of the prior art having an equivalent resistance, of the order of 40 to 60% in the case of solid slabs for example.

According to an advantageous characteristic, said second body is placed in the middle of the height of said first body in the cross section where the bending moments algé¬ bricks maximum and minimum of the third part of said envelope curve bending moments are on average weak or zero.

According to another advantageous characteristic, said second body adopts, in the third part of said envelope curve, moments bending a slope of the order of 20%. The invention will be better understood, and other characteristics and advantages will appear on reading the following description of exemplary embodiments of a beam structure according to the invention, accompanied by the accompanying drawings, examples given by way of illustration. 'illus¬ tration and without any restrictive interpretation of the invention can be drawn from it.

Figure IA shows a cross-sectional view of a work of the prior art of the frame bridge type.

Figure IB shows the curves representative of the bending moments of the structure of Figure 1 A.

Figure IC shows schematically and in cross section the main metal frame of the structure of Figure IA. Figure 2A shows a longitudinal sectional view of a prior art structure of the multiple beam bridge type connected together by a slab.

Figure 2B partially shows curves representative of the bending moments of the structure of Figure 2 A.

Figure 2C shows a cross-sectional view along line Eϋ-II of the structure of Figure 2A.

Figure 3A shows a longitudinal sectional view of a prior art structure of the bridge type with masts and shrouds.

Figure 3B shows the curves representative of the bending moments of the structure of Figure 3 A.

Figure 4A shows in longitudinal section a first exemplary embodiment of a beam structure according to the invention.

Figure 4B shows a representative bending moment envelope curve applicable to the example of Figure 4A. Figure 4C shows a cross-sectional view along line I-I of Figure 4A.

Figure 4D shows a cross-sectional view along line LT-II of Figure 4A.

Figure 4E is a cross-sectional view along the line Hl-πi of Figure 4A.

Figure 5 shows the example of Figure 4A in perspective. Figure 6 shows a partial perspective view of a second exemplary embodiment of a beam structure according to the invention.

FIG. 7 represents a partial perspective view of a longitudinal assembly of two beam structures according to FIG. 6.

Figure 8 shows in partial and perspective view a first method of lateral assembly of two beam structures according to the invention.

Figure 9A shows in longitudinal section a third embodiment of a beam structure according to the invention.

Figure 9B shows in perspective the beam structure of Figure 9A.

Figure 10A shows in longitudinal section a fourth embodiment of a beam structure according to the invention.

Figure 10B shows in perspective the beam structure of Figure 10 A.

Figure 11 shows in half cross section a first example of a method of realizing a horizontal structure according to the invention forming a bridge deck.

FIG. 12A shows in perspective and in exploded view an example of a method of assembling beam structures according to the invention.

Figure 12B shows in half cross-section a second exemplary embodiment of a horizontal structure according to the invention forming a bridge structure, obtained by the method of assembly shown in Figure 12 A.

Figure 13A shows in perspective and in partial view an exemplary embodiment of a structure according to the invention forming a bridge structure.

Figure 13B shows in cross section the example of Figure 13A.

Figure 13C shows in perspective and in enlarged view a detail of the example of Figure 13 A.

Figure 14 shows in perspective and in partial view a fifth example of embodiment of a beam structure according to the invention.

Figure 15A shows a side view of a sixth exemplary embodiment of a beam structure according to the invention.

Figure 15B shows in partial and perspective view the beam structure of Figure 15A.

Figure 16A shows in longitudinal section an exemplary embodiment of a vertical structure according to the invention forming a retaining wall.

Figure 16B shows a curve representative of the bending moments of the structure of Figure 16 A. Figure 17 shows in cross section a seventh example of embodiment of a beam structure according to the invention.

Figure 18 shows in perspective an exemplary embodiment of a vertical structu¬ re according to the invention forming a reservoir.

Figure 19A shows in partial view and in cross section a second method of lateral assembly of two beam structures according to the invention.

Figure 19B shows in partial view a longitudinal section along the line I-I of Figure 19 A.

Figure 19C shows in perspective a first particular element used in the assembly mode shown in Figure 19 A. Figure 19D shows in perspective a second particular element used in the assembly mode shown in Figure 19 A.

Figure 19E shows in cross section an enlarged detail of Figure 19 A.

The beam structure 10 shown in FIG. 4A rests on a simple support 14 at one of its ends, on a simple support 16 at the other end and on a simple support 15 in its central part, and comprises a first prismatic body 11 of rectangular section for example, a third prismatic body 12, for example of rectangular section, facing the first body 11 and parallel thereto as shown in Figures 4C, 4D, 4E. The first and third bodies have a length defining the length of the beam structure 10 and a height h which is advantageously constant over the length of the beam structure 10 and defining the height of the latter. The beam structure 10 comprises a second body 13 which connects the first 11 and third 12 bodies along the length of these latter in a position variable in height relative to the first or third body as shown in Figure 4A and Figures 4C , 4D, 4E, as a function of the curve of the bending moments shown in FIG. 4B, so that the second body 13 is positioned in the compressed area of a cross section of the beam structure 10. The first, second, and third body form a beam structure 10 mo¬ nobloc and consist of reinforced concrete, or any other known molded material, the reinforcements (not shown) will advantageously be distributed in the concrete by any known means. The envelope curve of the bending moments shown in Figure 4B is developed from constant and variable bending forces applicable to the beam structure on the three simple supports, by any means and any known calculation method. This curve takes into account permanent loads, in particular the dead weight of the beam structure and variable overloads, for example a mobile moving along the length of the beam structure. The bending moment curve shown in Figure 4B is given by way of example, and therefore the ordinate axis of the moment values has not been deliberately graduated.

The envelope curve of the moments shown in Figure 4B shows maximum positive moments in absolute value in spans, and maximum negative moments in absolute value in the area of the central support 15. For each cross section of the beam, parallel at the ordinate axis in FIG. 4B, the moment envelope curve indicates the applicable algebraic bending moments, which are maximum on the curve C1 and minimum on the curve C2. When we consider the span between the supports 14 and 15, we see that the moments are always positive in a part of the beam structure close to the support 14; the second body 13 will then be placed at the upper end of the first 11 and third 12 bodies as shown in FIG. 4C; it should be noted that the bending moments being decreasing in order to cancel out at the simple support 14, the second body 13 could be placed at any point of the height of the first and third bodies, and the upper end of the latter will be placed for to simplify manufacturing and reduce costs. We also note that the moments are always negative in a part of the beam structure adjacent to the support 15; the second body 13 will then be placed at the lower end of the first 11 and third 12 bodies as shown in Figure 4E. Between the above two parts of the beam structure, subject either to always positive moments or to always negative moments. there is an intermediate part for which the moments will be positive or negative depending on the position of the variable overloads on the beam structure; the second body 13 will then adopt a variable position between the upper and lower extreme positions defined above, as follows: the second body 13 will be placed in the middle of the height of the first and third bodies, as shown in Figure 4D, for the cross section where the maximum and minimum algebraic mo¬ ments will be low or zero on average, the skilled person must then ensure that the dimensions of this cross section are sufficient to withstand the maximum and minimum bending moments given by the envelope curve moments at the corresponding abscissa; the second body 13 will provide longitudinal continuity between the upper and lower extreme positions passing through the intermediate position defined above so that each cross section is able to withstand the maximum and minimum bending moments defined by the envelope curve of the moments to the corresponding abscissa. It should be noted that the second body 13 can be extended axially at the top or bottom end of the first 11 and third 12 bodies in the intermediate part for which the moments can be positive or negative, and that conversely, the variation in position of the second body can begin while the bending moments are all positive or all negative, any cross section of the beam structure must always be able to resist the maximum and minimum algebraic moments given by the curve enveloping moments with the corresponding abscissa. The second body 12 will adopt, in its variable position part, preferably a slope of the order of 20% without exceeding 30%; if a slope greater than 30% proves necessary as a function of the envelope curve of the moments, the person skilled in the art will preferably choose to increase the height h of the first and third bodies for example. Figures 4C, 4D, 4E show that the first 11, second 13, and third 12 bodies define a cross section of the beam structure 10, varying from an II shape to a U shape on the span between supports 14 and 15, passing through an H shape.

In the span between the supports 15 and 16 of the example in FIG. 4A, the position of the second body 13 on the beam structure is defined by symmetry with respect to a transverse plane passing through the continuous support 15.

The height h and the thickness of the first and third bodies, advantageously constant in the example of FIG. 4A, will be defined in any known manner, in particular as a function of the admissible deflection. The width and thickness of the second body 13 will be challenged in any known manner, in particular as a function of the moments of inertia of the first and third bodies in order to ensure the resistance of the beam structure to the applicable bending moments. It will be noted that the first and third bodies have been shown to be parallel defining a constant width of the second body 12 over the length of the beam structure, but may alternatively be non-parallel and form between them an angle of small opening. This angle will advantageously be a function of a general width to be given to the beam structure, depending on the architecture of the project to be carried out and which may impose different widths at the two ends of the beam structure.

It should be noted that the second body, which has been shown with a veil of constant thickness throughout the beam structure, can adopt a veil of variable thickness depending on the curve of the shear forces (not shown) applicable to the beam structure 10. Indeed, towards the supports, the shearing force is maximum and the thickness of the second body may be greater there than in the span where the shearing force is lower. The thickness variation over the length of the beam structure can advantageously be done continuously.

The beam structure according to the invention shown in Figure 4A comprises a first, a second and a third body. Another exemplary embodiment could consist of a beam structure comprising only a first body and a second body connected laterally to the first body, as defined above. The second body may or may not extend symmetrically laterally on either side of the first body.

Figure 5 shows in perspective the beam structure according to the invention shown in Figure 4A, the supports have not been shown.

It will be noted that the beam structure according to the invention is advantageously in the form of a modular structure and may include steels waiting at the end of a module in order to ensure the continuity of the stretched part of its section on continuous support with another module, as shown for example in Figures 6 and 7. In Figures 6 and 7, the elements performing functions similar to those of the elements of Figures 4A, 4C, 4D, 4E are assigned same references. In FIG. 6, the first 11 and third 12 bodies of a module 20 comprise steels 18 waiting for a continuity of the module 20 with another module 20, as shown in FIG. 7, by concrete molding for resume the bending moments in the stretched part of the section with continuous support 15, the bending moments in the compressed part of the transver¬ dirty section with support 15 being taken up by the second body (not shown) placed at the lower end of the first and third bodies on the modules 20.

Figure 8 shows two beam structures intended to be connected laterally to allow a distribution of the forces due in particular to overloads, and thus ensuring the construction of a bridge deck with parallel beams for example. The beam structures forming the deck are placed in parallel, and two adjacent beam structures are advantageously linked by pouring concrete, after installation, by means of lateral frames 21 and of reservations 22 provided for this purpose in two bodies 11 and 12 adjacent respectively, as shown in FIG. 8, in which the longitudinal steels are not shown. The lateral connection points between two adjacent beam structures will advantageously be regularly distributed over the length of these. Each beam structure making up a horizontal or vertical structure as described below can thus be connected laterally to two adjacent beam structures, if necessary. Figures 9 A and 9B show a beam structure according to the invention forming an arch bridge. The strucmre comprises a first 11, a third 12, and a second 13 body, the latter defining in a single piece the deck and the abutments of the arch bridge. The first 11 and third 12 bodies respectively comprise, perpendicular to a longitudinal axis of the first body, a first extension at one end and a second extension at the other end, the second 13 body being connected laterally. to the first and second extensions along the length thereof. according to a variable position on a height h of the first and second extensions, as a function of the bending moment curve (not shown), so that the second body is positioned in the compressed area of a cross section of the first and second extensions. It will be noted that the second body 13 has an apron shape suitable for central support on the pillar according to the bending moment curve (not shown). Note that in Figures 9A and 9B, the second body 13 for the abutments is shown in a constant position relative to the first and third body due to the low height of the abutments. The second body can advantageously adopt a variable position on the abutments according to the curve of the bending moments for these as will be explained later.

It will be noted that the beam structure shown in FIGS. 9A and 9B may only take an extension perpendicular to only one of its ends if necessary, the other end then resting on any other type of support. Figures 10A and 10B show a beam structure according to the invention forming an arch bridge, similar to that shown in Figures 9A and 9B but whose second body 13 adopts an apron shape avoiding the use of a central support.

Figure 11 shows a horizontal structure forming a bridge deck comprising a plurality of beam structures 30, 31 according to the invention placed longitudinally and parallel. The beam strucmres support, for example in a manner known as shown in FIG. 11, a sealing layer 33 following in particular the profile of the second body 13 making it possible to form low points on the sealing layer and thus to collect the drainage water in the area of the continuous supports, a layer of insulating material 32 which is advantageously light and not very compressible, for example of the polystyrene type or the like, the thickness of which will advantageously be constant, and a drainage layer 37 whose thickness will advantageously be variable to form a substantially flat layer capable of receiving a pavement 34 of constant thickness. A sidewalk 35 supporting a bodyguard has also been shown. Two adjacent beam structures making up the deck can advantageously be connected laterally as explained above. Figures 12 A and 12B show an example of a method of assembling beam structures according to the invention allowing the production of a horizontal structure according to the invention forming a bridge structure. The deck comprises a plurality of beam structures 40 according to the invention placed parallel and transverse to the longitudinal axis of the deck, which is supported by two beams 41 and 42 according to the invention placed longitudinally, as shown in Figure 12 A. It should be noted that only a beam structure comprising the deck has been shown. The beam structure 42 has been shown resting on a abutment 45. The cantilevers 43 and 44 formed by the ends of the beam strucmre 40 are advantageously raised as shown in Figure 12 A. This type of structure is more particularly intended for large spans. In FIG. 12B, the various layers forming a pavement are shown in a similar manner to FIG. 11.

Figures 13A and 13B show an exemplary embodiment of a strucmre according to the invention forming a frame bridge. The horizontal strucmre forming the deck 50 includes a plurality of beam structures according to the invention placed parallel and transversely to the longitudinal axis of the bridge, the ends of which rest by means of recessed supports 54, 55 on vertical strucmers according to the invention forming the abutments 51 and 52. The abutments 51 and 52 are each formed by a plurality of beam structures according to the invention placed parallel and vertically, as shown in Figure 13 A. The abutments 51 and 52 rest by means of supports embedded on a slab 53, itself resting on a laying concrete 58. The curves representative of the bending moments applicable to the deck and at the abutments of the framework bridge shown in Figure 13 A are shown in Figure IB. It should be noted that this type of curve applies to permanent loads or overloads which are often predominant. The beam structures according to the invention forming the sections 51 and 52 and the deck 50 are determined as a function of the curves of the respective bending moments as explained above. Two adjacent beam structures making up the deck or the abutments can advantageously be connected laterally as explained above. It will be noted that, given the lightening of the structures due to an optimization of the sections of concrete working in compression, an apron 50 or a abutment 51, 52 can advantageously be prefabricated in one piece, as the case may be, thus advantageously forming a one-piece construction module.

As required, in particular according to the available location and for aesthetic considerations, the beam structure according to the invention forming the front end of the structure for the abutments or for the deck, for example the beam structure 57 for¬ mant the front end of the abutment 52 in Figure 13A, may advantageously include only a first 11 body and a second 13 body. In this case, the second body 13 forming the end of the abutment 52 may be produced with a variable width, which makes it possible to adapt the end of the structure according to the architectural dimensions imposed by the site. If necessary, a lateral connection between the beam structure 57 and the adjacent beam structure should advantageously be made to ensure stability during dumping. Figure 13C shows the detail of the steels awaiting molding at one end of the beam structures forming the deck and at the upper end of the beam structures forming a abutment, so as to ensure the realization of a recessed support taking up bending moments. It will be noted that the upper end of the beam structures forming the abutments advantageously comprises a platform 56 in order to facilitate the casting of the supports. Figure 14 shows a method of assembly similar to that of Figure 12 A but which differs from the latter by beam structures 61 and 62 longitudinal support of the deck, the first 11 and third 12 bodies include openings 63 The openings 63 are advantageously placed in the tensioned areas of the first and third bodies of the beam structure, for example as shown in FIG. 14, and therefore make it possible to advantageously lighten any beam structure according to the invention without modifying its own resistance.

Figures 15 A and 15B show an example of a beam structure in which the first 11 and third 12 bodies have a variable cross section allowing the second body 13 to have greater variations in height positions in order to obtain higher moments of inertia. . This type of beam structure is more particularly suitable for large spans. It will be noted that the second body can advantageously extend outside the third body 12, as shown in FIG. 15B, depending on the needs, the available location, the aesthetic appearance, or the constraints of resistance, in particular to increase the section working in compression without modifying the gap first and third corps.

Figure 16A shows a retaining structure comprising one or more beam struc¬ mers according to the invention placed parallel and vertically. The beam structure 70 forming the retaining wall is embedded in the ground at one end, and may advantageously include a support in the upper part in the form of a tie rod 71 anchored in the embankment and fixed to the beam structure, as shown in FIG. 16 A. The beam structure 70 according to the invention advantageously comprises a first 11, a second 13, and a third body (not shown), the second body 13 adopting a variable position on the height h as a function of the applicable bending moment curve, notably shown in Figure 16B. The curve of the bending moments represented in FIG. 16B shows zones of negative moments at the supports, that is to say at the tie 71 and at the embedding in the ground, and a zone of positive moments between supports due mainly to the thrust of the embankment. The second body 13 will vary in position over the height h so that it is positioned in the compressed areas of a beam structure, as described above. It should be noted that, depending on the height of the retaining wall, a plurality of anchor rods can advantageously be placed along the beam structures making it up, which determines a different bending moment curve taking into account each tie in as a simple support, and therefore a position of the second body adapted as a function of this curve. It will be noted that, as for the abutments of the structure shown in Figure 13A, the retaining wall according to the invention can advantageously be prefabricated in one piece as the case may be.

Figure 17 shows a beam structure made of prestressed or post-stressed concrete. For this purpose, cables (not shown) can advantageously be placed in a longitudinal manner inside housings 82 provided in the first 11 and third 12 bodies of a beam structure 80, 81 according to the invention, as shown in Figure 17 for example. The beam structure according to the invention can advantageously comprise transverse housings 83 in the second body 13, whether or not provided with sheaths, capable of ensuring the passage of tension cables (not shown) transversely through a plurality of beam structures 80, 81 parallel forming a bridge structure, as partially shown in FIG. 17. It should be noted that the long-tension cables can be placed alternately in long recesses formed for this purpose in the outer part first and third bodies for example, this technique being called external post-stressing.

The vertical strucmre forming a reservoir or a balance chimney according to the invention represented in FIG. 18 comprises beam strucmers 91, 92, 93 according to the invention placed horizontally and stacked on one another to form the four walls d 'a reservoir, as shown in Figure 18. Four pillars of angles 94 at the four corners of the vertical structure provide the connection of the walls together. The profile of the second bodies of each of the beam structures 91, 92, 93 is determined according to the respective curves. bending moments as explained above, which are established, for example in the case of a tank, mainly as a function of the pressure exerted by the content on the walls of the tank. A general foundation 95 ensures the tightness of the opening in its bottom, the tightness of the walls being advantageously ensured by any known means between the stacked beam structures, or by any suitable waterproof coating placed on the interior surface. walls.

The two beam structures according to the invention shown in FIG. 19 A are assembled by means of their third 12 bodies and first respective 11 bodies. To this end and by connection point, as shown in FIG. 19 A, two tubular elements 100, advantageously metallic, will be fixed transversely in the third 12 and first 11 bodies, for example beam structures to be assembled, respectively. The two tubular elements 100 must be substantially aligned when the beam structures are in the assembly position, so as to allow the placement axially, inside the tubular strucmers 100, of a metal bar 106 capable of resisting transverse shear forces of length slightly less than the thickness of the first and third bodies and of the seal 110 between the latter. The bar 106 will advantageously be kept inside the elements 100 by means of the injection of a bonding agent 109, consisting of mortar for example, in order to allow, via the dirty cross-section thus obtained, composed of the bar 106 and the bonding agent 109, the distribution over the two beam structures thus assembled, in particular the effects of a variable overload applied to one or the other of the beam structures. The bonding agent 109 thus rigidly linking the bar 106, the first body 11 and the third body 12, will be advantageously injected over the total length defined by the thickness of the bodies 11 and 12, and so that it does not flow into the seal 110 between the first 11 and third 12 bodies, a sealing element 111 will be placed before the injection inside and between the two tubular elements 100.

FIG. 19D shows an exemplary embodiment of the sealing element 111 which comprises a flexible tubular central part 108, for example a rubber tube, in order to absorb a possible misalignment of the two tubular elements 100, as shown in detail in FIG. 19E, and an elastic ring 107 fixed to each axial end of the tubular central part 108, so as to keep the element 111 in contact and airtight with each of the two tubular elements 100.

FIG. 19C shows an exemplary embodiment of a tubular element 100 which comprises a metal tube of length substantially equal to the thickness of the first or third body in which it is inserted, on which are fixed, for example by welding, two horizontal plates 101 and a vertical plate 102, each plate 101 and 102 comprising a hole 103 intended to allow the passage of metallic reinforcements, vertical 105 and horizontal 104 respectively as shown in Figure 19B. The purpose of the frames 104 and 105 and of the plates 101 and 102 is to allow a better distribution of the ef- strong in the lateral connection zones of the assembled beam structures.

It will be noted that the lateral connection point as described above in support of FIGS. 19A to 19E may advantageously be multiplied over the length of two adjacent beam structures in order to ensure a distribution of the forces over the length of these. this. Furthermore, each beam structure making up a horizontal or vertical structure can thus be connected laterally to two adjacent beam structures, if necessary.

It will be noted that the beam structure according to the invention can find numerous applications, in particular according to the examples of embodiments and combinations of assembly described above and according to other combinations that those skilled in the art may easy to apply, in particular in the building for the construction of floors (horizontal structures) and the construction of retaining walls, supporting walls, or partitions (vertical structures) for example.

Claims

1. Beam structure intended to be subjected to at least one bending force determining along said beam structure a curve enveloping the bending moments which comprises at least a first part in which the bending moments are of the same first sign, at least a second part in which the bending moments are of the same second sign opposite to said first sign, and at least a third part in which the bending moments can be of said first sign or of said second sign or zero, said strucmre of beam comprising in particular concrete, at least a first (11) body whose height and length respectively define the height and the length of said beam structure, characterized in that said beam structure includes a second (13) body laterally connected to said first body along the length of said first body, said second body being placed at an end upper half of the height of said first body in the first part of said curve enveloping bending moments, said second body being placed at a lower end of the height of said first body in the second part of said curve enveloping bending moments, and in this that said second body is continuous longitudinally and placed in a variable position over the height of said first body, from said high end to said low end in the third part of said curve enveloping bending moments.

2. Beam structure according to claim 1, characterized in that said second body (13) is placed in the middle of the height of said first (11) body in the transverse section where the maximum and minimum algebraic bending moments of the third part of said envelope curve bending moments are on average weak or zero.

3. Beam structure according to claim 1 or 2, characterized in that said second body (13) adopts, in the third part of said envelope curve, moments bending a slope of the order of 20%.

4. Beam strucm according to any one of claims 1 to 3, characterized in that said at least first body (11) comprises, perpendicular to a longitudinal axis of said first body, at least one first extension at one end, and in that said second (13) body is connected laterally to said first extension over the length thereof, according to a variable position over a height (h) of said first tension, as a function of said moment envelope curve bending, so that said second body is positioned in the compressed area of a cross section of said first extension.

5. Beam structure according to claim 4, characterized in that said at least first body (11) comprises, perpendicular to a longitudinal axis of said first (11) body, at least one second extension at the other end, and in that said second (13) body is laterally connected to said second extension lengthwise thereof, in a variable position over a height (h) of said second extension, as a function of said bending moment curve, so that said second body is positioned in the compressed area of a cross section of said second extension.

6. Beam strucm according to any one of claims 1 to 5, characterized in that it comprises a third (12) similar body and facing said first body, said third body being connected to said second body (13).

7. Beam structure according to claim 6, characterized in that said first (11), second (13), and third (12) bodies define a cross section of the beam structure, varying in form in LT to a U shape over at least part of the length of said beam structure, passing through an H shape.

8. Beam structure according to claim 6 or 7, characterized in that said second (13) body extends outside said first (11) and / or third (12) body.

9. Beam structure according to any one of claims 6 to 8, characterized in that σ "e said first (11) and third (12) bodies are parallel.

10. beam structure according to any one of claims 1 to 9, characterized in that said first (11) and / or third (12) body comprise openings (63).

11. Girder structure according ^'to any one of claims 1 to 10, caractéri¬ See in that said second (13) body comprises a web of variable thickness.

12. Construction module, characterized in that it comprises a plurality of beam structures according to any one of claims 1 to 11, said beam structures being positioned in parallel and made in one piece.

13. Horizontal structure, characterized in that it comprises at least a plurality of beam structures according to any one of claims 1 to 11, said beam structures being positioned in parallel.

14. Horizontal strucmre according to claim 13, characterized in that it com¬ takes connecting means for laterally connecting at least two adjacent beam structures.

15. horizontal strucmre according to claim 13 or 14, characterized in that it comprises at least one beam structure according to any one of claims 1 to 11 positioned perpendicular to said plurality of beam strucmers and in a plane pa¬ parallel to this one.

16. Vertical structure, characterized in that au 'it comprises at least a plurality of beam structures according to any one of claims 1 to 11, said beam structures being positioned in parallel.

17. Vertical structure according to claim 16, characterized in that αw 'it com¬ takes connecting means for laterally connecting at least two adjacent beam structures.

18. Structure according to claim 14 or 17, characterized in that said connecting means comprise at least a first tubular element (100) fixed in a trans- 11

in the first (11) body of a beam structure, a second cellular element (100) fixed transversely in the first (11) or third (12) body of said adjacent beam structure, a bar (106) able to withstand shear forces, placed inside said first and second tubular elements, a connecting agent (109) making it possible to rigidly link said bar, said first body of a beam structure, and the first or third body of said adjacent beam structure.

19. Work, characterized in that it comprises a horizontal strucmre according to any one of claims 13 to 15, 18, and at least one vertical structure according to any one of claims 16 to 18.