FR2643404A1 - INSTALLATION FOR THE MANUFACTURE OF PRE-STRESSED CONCRETE ELEMENTS, IN PARTICULAR ELONGATE CONSTRUCTION ELEMENTS - Google Patents

Abstract

Installation for the production of prestressed concrete elements comprising an elongated manufacturing area 10, means 20, 22 for the tensioning of prestressing reinforcements 24 and a molding apparatus comprising a movable assembly 18 supporting a multiplicity of elements molds 34, 36, 38 parallel to the longitudinal direction of the manufacturing area. Each mold element comprises, at its rear end, an end shaping device 42, 44, 46 making it possible to conform to precise dimensions the section of the molded elements P1, P2.

Description

Installation for the production of precast concrete elements

  The invention relates to an installation for the manufacture of prestressed concrete elements, in particular elongated construction elements, such as posts, beams,

beams or the like.

  It relates more particularly to such an installation which comprises an elongated manufacturing area, means for tensioning prestressing reinforcements above the manufacturing area and a molding apparatus comprising a movable unit movable in translation on the manufacturing area and supporting a multiplicity of mold elements parallel to the longitudinal direction of the manufacturing area to form the side walls of molds, the bottom of which is formed by the manufacturing area, which makes it possible to manufacture the elements, one after the other, of a

  across the manufacturing area.

  Patents of this type are already known.

  French 72 31148 and 79 07427 in the name of the Claimant.

  These known installations are used for the manufacture, by spinning, on large manufacturing areas, typically of a hundred meters in length for a width of 2.5 m, of prestressed concrete construction elements, in particular beams with a general T-shaped section. With these known installations, tension is put in place

  prestressing reinforcement above the manufacturing area

  tion, first fractions of elements are made by pouring concrete around said reinforcements in the molds formed by the molding apparatus and, after pouring the concrete, the elements of the molds forming the side walls are made to slide.

  for the production of other fractions of elements.

  Also, for the molding, front walls are provided.

  the end pieces capable of being moved over the manufacturing area as the elements are molded. After the molding operation, the concrete is left to harden, advantageously by accelerating the latter by steaming, and then the tension of the reinforcements is released.

  after sufficient hardening of the concrete.

  The object of the invention is in particular to improve the known installations of this kind so as to obtain molded elements having reduced dimensional tolerances, a more precise cross-sectional outline, and having increased performance and mechanical characteristics. It is also an object of the invention to provide such an installation which makes it possible to manufacture a greater number of elements, and this for the same width of the manufacturing area. The invention proposes an installation of the type defined in the introduction, in which, according to an essential characteristic of the invention, each mold element comprises at its rear end, relative to the direction of movement of the moving assembly, a shaping device end of cross section substantially wider, in at least one direction, than that of the current section of the corresponding mold element, which makes it possible to define, between two adjacent shaping devices, a section of precise dimensions and to conform, at said dimensions, after pouring the concrete, the cross section of the molded elements

on the manufacturing area.

  These shaping devices allow, in combination with the manufacturing area, to conform to precise dimensions the products molded on three sides, namely the two sides.

side and the underside.

  As a result, the products obtained have better

dimensional tolerances.

  According to another characteristic of the invention, each mold element comprises a core suitable for being arranged parallel to the longitudinal direction of the manufacturing area and in a vertical arrangement and extending over the entire length of the mold element , said core being provided, on at least one of its vertical faces, with a resistant shaping element removably mounted at the rear end of the core and with a hollow half-shell fixedly mounted

  over the entire remaining length of the core.

  Thus, the shaping elements, which in fact constitute wearing parts, can be replaced easily, while the hollow shells which wear much less than the shaping elements remain permanently attached to

the mold element.

  Advantageously, the mold elements comprise two lateral mold elements framing intermediate mold elements, the core of each lateral mold element comprising a shaping element and a half-shell on one of its vertical faces, the core of each element. of an intermediate mold comprising a shaping element and a

  half-shell on each of its two vertical faces.

  Advantageously, each shaping element is a solid block provided with internal millings for its removable fixing on

  the core, thanks to screws driven into said millings.

  According to another characteristic of the invention, the installation comprises a compacting device capable of conforming and compacting the top face of the elements molded in the region.

  end conforming devices.

  This compacting device, which is concerned with the fourth face, or upper face, of the molded elements has a double function. It acts as a height adjuster to calibrate each molded element at its correct height just before demolding and it then acts as a compactor by exerting pressure on the upper face to force the concrete to compress in the rear part of the die, which corresponds to the

  end compactor.

  Advantageously, the compacting device comprises a lifting frame pivotally mounted relative to the movable assembly between a raised position of rest and a lowered position

of work.

  In a preferred embodiment of the invention, the frame carries two parallel tubes, arranged horizontally and transversely to the direction of movement of the moving element, these tubes being adapted to be driven in an alternating movement by means of '' an eccentric motor to come both to bear in the working position, on top of the mold elements in line with the devices

end conformers.

  In the following description, given only as

  example, reference is made to the accompanying drawings in which: - Figure 1 is a top view of an installation according to the invention; - Figure 2 is a side view of an intermediate mold element; - Figure 3 is a sectional view along line III-III of Figure 2; - Figure 4 is a sectional view along the line IV-IV of Figure 2; - Figure 5 is a sectional view of a side mold element along the line V-V of Figure 1; - Figure 6 is a sectional view of the same side mold element along the line VI-VI of Figure 1; - Figure 7 is a sectional view of two intermediate mold elements at their current section and showing the cross section of a molded element; - Figure 8 is a sectional view of two intermediate mold elements, at their end shaping device showing the shape of the section of the molded element; - Figure 9 is a side view of the moving assembly; - Figure 10 is a partial view; on an enlarged scale, of the mobile assembly of FIG. 9; - Figure 11 is a partial top view along arrow XI of Figure 10; and - Figure 12 is a front view along arrow XII of

Figure 10.

  First of all, reference is made to FIG. 1 which shows a manufacturing area 10 of generally rectangular shape comprising, in a manner known per se, a metal deck supported by a masonry body and capable of being heated to cause steaming concrete. This manufacturing area which may have, for example, a length of about 100 m, for a width of about 2.5 m, is limited by two end edges 12 and 14 and by two longitudinal edges carrying two parallel rails 16 used for the translational movement of a movable assembly 18 over the entire length of the area 10, from one to the other of its ends. The installation further comprises two end heads 20 and 22 used for anchoring and tensioning a multiplicity of prestressing reinforcements 24 arranged above the manufacturing area and parallel to the direction longitudinal of this

last.

  The mobile assembly 18 comprises a frame formed by a trans-

  front versal 26 and a rear transverse block 28 joined together by two lateral side members 30 and 32. The frame of the movable assembly 18 is intended to receive, in a removable manner, a molding apparatus comprising a multiplicity of parallel mold elements to the longitudinal direction of the bench and assembled together in a manner which will be described

  in more detail with reference to Figure 9.

  In the example, these mold elements, which are intended for

  form the side walls of the molds, include seven elements

  elements: two side elements 34 and 36 and five elements

identical 38 inserts.

  These seven mold elements thus form the side walls of six molds used for the manufacture of six elongated elements produced one after the other, from the end 12 of the manufacturing area 10 to its end 14. In the example shown in Figure 1, a first series of six P1 elements was manufactured and a

  second series of six P2 elements is being manufactured.

  The molding process is essentially that described in the two aforementioned French Patents, which can be

  refer for further explanation.

  Briefly, the molding process consists first of all in putting in place the prestressed reinforcements under tension, in manufacturing a first fraction of elements (in the example the elements Pl} by pouring concrete around said reinforcements in the molds limited by the manufacturing area and by the mold elements 34, 36, 38, while putting in place end end walls 40 (FIG. 1). The concrete is then vibrated, the moving element 18 is then moved in the direction of arrow F (Figure 1) to slide the elements 34, 36 and 38 forming the side walls of the molds, the front wall of the molds is again moved and the operation is repeated to pour a new quantity of

concrete.

  According to the invention, each mold element 34, 36 or 38 comprises, at its rear end with respect to the direction of movement of the movable element 18, an end shaping device 42, 44 respectively for

  elements 34 and 36 and 46 for elements 38.

  These conforming devices 42, 44, 46 define between them, two by two, a section of precise dimensions, which makes it possible to conform, after pouring the concrete, the cross section

  molded elements on the manufacturing area.

  It will be understood with reference to FIG. 1, that the elements P2 which are in the process of being manufactured, see their respective cross section shaped by the devices 42, 44 and 46 as the moving element 18 moves in the direction of the arrow F. We now refer to FIG. 2 which shows an intermediate mold element 38. This element comprises a core 48 capable of being arranged parallel to the longitudinal direction of the manufacturing area and in a vertical arrangement. This core 48 has the general shape of an L and comprises a horizontal branch 50 extending over the entire length of the mold and connecting, at its rear end, to a vertical branch 52. The branch 50 supports, in its rear part , a shaping device 46 and, over its entire remaining length, two shells 54a and 54b which are connected to the shaping device 46 by a transition section 56. As shown in FIG. 3, the core 48 of the mold element 38 is a flat iron arranged vertically and comprising two opposite faces 58a and 58b. The half-shell 54a is a sheet folded at 60a according to a rounded shape and has one end 62a welded to the face 58a and another end 64a welded to the edge of a horizontal flat iron 66, itself welded to the core 48. The half-shell 54b constitutes the symmetrical of the half-shell 54a and also comprises a rounded folding 60b and two end edges 62b and 64b welded respectively to the core 48 and to the flat iron 66. The flat iron 66 determines a face upper flat and horizontal 68, the total height of the element between this face 68 and the lower edge

  horizontal 70 of core 48 being equal to Hl.

  We now refer to Figure 4. The device conforma-

  teur- 46 comprises two shaping elements 46a and 46b constituted by solid blocks fixed on either side of the core 48 respectively against the faces 58a and 58b. These blocks have, in cross section, a shape very close to that of the half-shells 54a and 54b. In the example, the block 46a comprises a lower face 72a connected by a sharp edge 74a to a lateral face 76a, the latter also being

  connected by a sharp edge 78a to an upper face 80a.

  The element 46b comprises, in a corresponding manner, faces 72b, 76b and 80b connected together by sharp edges 74b and 78b. The faces 80a and 80b are flat and horizontal and distant from the lower edge 70 of the core 48 by a distance H2 slightly less than the distance H1 (FIG. 3). The block 46b comprises four holes 82 used for the introduction of four screws 84 (FIG. 2 and FIG. 4) capable of passing through corresponding holes 86 of the core 48 and of being

  screwed into threads 88 formed in element 46a.

  After fitting and tightening the screws 84, it is possible to put a putty in the holes 82, so as not to

  cause discontinuities in the face 76b.

  Referring now to Figure 5 which shows a side mold member 34, it comprises a core 90 of the same shape as the core 48 described above and having two vertical faces 92a and 92b. This core is surmounted, as in the case of FIG. 3, by a flat iron 66 and it also comprises a half-shell 54b welded on the one hand to the face 92b and on the other hand to the flat iron 66. On the on the other side of the core 90 is provided a hollow stiffening section 94 which is welded to the face 92a with the interposition of a flat iron 96. In the example, the section 14 is a hollow section of square section. Furthermore, the profile 94 is connected to the flat iron 66 by a folded sheet 98 whose one edge 100 is welded to the profile 94 and whose other edge 102 is welded to one edge of the iron 66. The sheet 98 has a flat upper face and horizontal 104 in the same plane as the upper face 68 of the flat iron 66. The height between this upper face and the lower edge 106 of the core 90 is also

equal to H1.

  As shown in Figure 6, the profile 94 and the sheet 98 extend over the entire length of the core 90. In the rear part of the core, the shaping element 42 comprises a single element 42b similar to the element 46b shown in FIG. 4. This element is fixed by screws 82 directly to the core 90. Over the entire length of the shaping element 42, the flat iron 66 is extended by a square iron 108 which is welded against the face 92a and which serves as a support for the end 102 of the folded sheet 98. The height of the assembly is equal to

  H2 as in the case of figure 4.

  It will thus be understood that the external shaping devices

  mite (Figure 4 and Figure 6) have a slightly lower height than that of the mold element in the rest of its length, that is to say on its current section (Figure 3 and

figure 5).

  Reference is now made to FIGS. 7 and 8. The end shaping device 46 (FIG. 8) has a substantially wider cross section, in at least one dimension (in the example the horizontal dimension), than that

  of the current section of the corresponding mold element.

  As a result, the distance D1 which separates the half-shells facing two adjacent mold elements (FIG. 7) is slightly greater than the distance D2 which separates the two adjacent shaping devices (FIG. 8) and this for a height given in relation to the plane of the area

manufacturing 10.

  In the example shown in FIGS. 7 and 8, the installation is used for the manufacture of P2 beams and prestressed concrete, each comprising three prestressing reinforcements 24. These beams have a section in the general shape of T arranged in an inverted position. This beam includes in particular a lower face which is in contact with the manufacturing area il and an upper face 112 which is, as will be seen below, leveled and compacted during its passage between the shaping devices 46. Thus when building element P2 passes between two adjacent shaping devices, for example between two devices 46, the cross section of this building element is gradually narrowed and brought to precise dimensions by the shaping devices. In addition, the section of the element obtained has sharp edges and not protruding edges, as was the case with the installation of

the prior art.

  In the part of the mold elements, corresponding to their current section, the particular assembly of the half-shells confers a high lateral inertia on these shells, the assembly thus having a lateral inertia, of 30%

  higher than that of existing mold elements.

  It should also be noted that the mold elements of the invention define both in the region of their current section (FIG. 7) and in the region of the end conformers (FIG. 8), a flat horizontal reference surface. In addition, this horizontal reference surface is connected, by sharp edges 78a and 78b (FIG. 8) with the lateral faces of the shaping elements. As a result, the mold elements have better lateral rigidity, which limits the deformation during the introduction of the concrete and gives, on demolding,

straighter molded elements.

  Furthermore, the fact that the upper face of the mold elements is planar and defines sharp edges with the elements

  conformers, the molded element can be leveled more perfectly-

  ment on its upper surface 112, as will be seen later, compared to the elements obtained in the prior art. In fact, previously, the mold elements had rounded edges, even on the upper face,

  which led to the formation of burrs on demolding.

  The shaping elements 46a and 46b, which form wear elements, can be easily replaced so that the molded elements always have a corresponding section

at the desired ratings.

  Advantageously, each end shaping device is formed of a material or comprises a coating of a material which facilitates the flow of concrete upon demolding and which thus reduces the skin tearing of the product. For example, elements can be made of chromed steel, stainless steel, ceramic, or elements comprising a coating of polytetrafluoroethylene or rigid nylon. Reference is now made to FIG. 9 in which the mobile assembly 18 is represented with its front unit 26, its rear unit 28 and one of its side members 32. This equipment moves on the rails 16 by means of wheels 114. The installation is in operation and ensures the molding of a series of P2 beams, a first series of Pl beams having just been molded and still being connected to the Pl series by cables.

prestressing 24.

  The two lateral mold elements 34 and 36 and the five intermediate mold elements 38 are assembled together using a front cross member 116 and a cross member

  posterior 118 to form an interchangeable "grid".

  The sleepers 116 and 118 are fixed respectively to the front block 26 and to the rear block 28. In a manner known per se, the side members 30 and 32 can be used for rolling a comb-beam (not shown) used for moving the

transverse molds 40.

  As indicated above, the mold elements 34, 36 and 38 ensure, in combination with manufacturing area 10, the molding of the elements on three faces, namely the two lateral faces and the bottom face. The invention also provides for molding the top face (face 112 in FIGS. 7 and 8) using a compacting device.

  generally designated by the reference 120 in FIG. 9.

  The device 120 comprises a lifting frame 122 pivotally mounted relative to the movable assembly 18 between a raised rest position (not shown) and a lowered working position (FIG. 9). The frame 122 is articulated, at one of its ends, by a horizontal axis 124 on a support 126 integral with the rear block 28. The frame 122, which has the general shape of a bracket, carries at its free end, two Parallel tubes 128 disposed horizontally and transversely to the direction of movement of the moving element 18. These two tubes are capable of being reciprocated and both come to bear, in the working position, on the top of the mold elements, in line with end shaping devices 42, 44, 46. The two tubes 128 (FIG. 11) are articulated with two end levers 134 and 136 around four hinge axes 138 to form a deformable parallelogram . The levers 134 and 136 are also articulated on the frame by means of respective axes 140 and 142. In addition, the lever 134, which is substantially longer than the lever 136, is articulated at 144 on a link 146 itself articulated on the eccentric 132. The tubes 128 are articulated to the levers 134 and 136 by the axes 138, which include springs 148. In addition, the articulation axes 140 and 142 of the two levers are mounted in two yokes end 150 by means of axes 140 and 142, the latter also being provided with springs 152 (FIG. 10). The two yokes are provided at the two ends of a transverse beam 154 mounted at the ends of two uprights 156 forming part of the frame 122. In addition, the end levers 134 and 136 are articulated on their respective axes 140 and 142 by connections. with ball joint 158 (figure 10). The calibration of the spring 152 is equal to the sum of the respective calibrations of the two springs 148. The frame 122, which is pivotally mounted directly on the moving element 118 and which, as a variant, could be pivotally mounted on a carriage coupled to said crew, ensures that the tubes 128 do not have any longitudinal relative movement with respect to the frame of the moving element 18. As a result, the tubes 128 are, in the working position,

  always in line with the end conforming devices.

  These tubes move only in a transverse relative movement, under the action of the eccentric movement transmitted

by the rod 146.

  The compactor device 120 has a double function: firstly it calibrates the molded elements at the desired height (H2) just before demolding and it exerts pressure on the fourth face (top face 112) to force the concrete to compress in the rear part of the mold elements (playing the role of die). In all cases, the second tube (the one located behind the direction of movement of arrow F) completes the work done

through the first tube.

  As a result, the molded elements are compacted laterally by the end conformers 42, 44 and 46

  and vertically by the compacting device 120.

  As a result, the mechanical resistance of the molded element is increased by about 30% to bending, since such an element, under bending stress, needs excellent concrete in the region of its upper face 112. This is extremely important for molded elements of elongated shape, such as beams or the like, which are precisely subjected to bending, which causes compression at their

upper faces.

  It also follows that the resistance dispersions of the

  molded elements "are reduced because the concrete is very homogeneous.

  Consequently, with equal concrete characteristics (same cement dosage), the molded element is more resistant in bending by around 30%. To obtain an equal flexural strength, the concrete may have a lower cement dosage. The result

a saving on the final cost.

  The invention is particularly applicable for the manufacture of elongate molded elements, such as beams, etc. Given the fact that the installation makes it possible to manufacture molded elements with sections with very precise dimensions, and with a much more homogeneous concrete, it is possible to manufacture, over an area of given width, much more molded elements than '' with the facilities of

the prior art.

  For example, on an area with a width of 2.50 meters, it is possible to manufacture series of twenty-six

beams.

  In addition, the installation makes it possible to obtain molded elements of precise section, the end shaping devices being able to be easily replaced in the event of

of wear.

Claims (16)

Claims.   1. Installation for the production of prestressed concrete elements, in particular elongated construction elements, such as posts, beams or the like, comprising an elongated manufacturing area (10), means (20, 22) for placing under tension of prestressing reinforcements (24) above the manufacturing area and a molding apparatus comprising a mobile assembly (18) displaceable in translation on the manufacturing area and supporting a multiplicity of mold elements ( 34, 36, 38) parallel to the longitudinal direction of the manufacturing area to form the side walls of molds, the bottom of which is constituted by the manufacturing area, which makes it possible to manufacture the elements (Pl, P2) the one after the other from one end to the other of the manufacturing area, characterized in that each mold element (34, 36, 38) comprises, at its rear end, with respect to the direction of movement (F ) of the moving crew, ad end shaping device (42, 44, 46) of substantially wider cross section, in at least one dimension, than that of the current section of the corresponding mold element, which makes it possible to define between two adjacent shaping devices a section of precise dimensions and to conform to these dimensions, after pouring the concrete,   the cross section of the molded elements.   2. Installation according to claim 1, characterized in that each mold element (34, 36, 38) comprises a core (48,) suitable for being arranged parallel to the longitudinal direction of the manufacturing area (10) and in a vertical arrangement and extending over the entire length of the mold element, said core being provided on at least one of its vertical faces (58a, 58b; 92a, 92b) with a shaping element (46a, 46b ) resistant removably mounted at the rear end of the core and a hollow half-shell (54a, 54b) mounted fixedly over the entire remaining length of soul.   3. Installation according to claim 2, characterized in that the mold elements comprise two lateral mold elements (34, 36) framing intermediate mold elements (38) and in that the core (90) of each element lateral mold (34, 36) comprises a shaping element (42b) and a half-shell (54b) on one of its vertical faces (92b), while the core (48) of each intermediate mold element (38 ) has a shaping element (46a, 46b) and a half-shell (54a; 54b) on each of its faces vertical (58a, 58b).   4. Installation according to one of claims 2 and 3,   characterized in that each shaping element (46a, 46b) is a solid block provided with internal millings (82) for its removable fixing to the core (48, 90) by means of screws (84) embedded in said milling.   5. Installation according to one of claims 2 to 4,   characterized in that each shaping element (46a, 46b)   has sharp edges (74a, 78a; 74b, 78b).   6. Installation according to one of claims 2 to 5,   characterized in that each half-shell (54a, 54b) has a lower free edge (62a, 62b) connected directly to the core (48, 90), for example by welding, and an upper free edge (64a, 64b) connected to the core by means of a flat iron   horizontal (66), itself welded to the core (48, 90).   7. Installation according to claim 3, characterized in that the core (90) of each side mold element (34, 36) has on its outer face (92a), opposite to that which receives the shaping element (46b) and the half-shell (54b), a hollow stiffening section (94) extending over all the length of the core (90).   8. Installation according to one of claims 1 to 7,   characterized in that the section of the end former (42, 44, 46) is connected to the current section of the element   mold by a transition zone (56).   9. Installation according to one of claims 1 to 8,   characterized in that the end shaping device (42, 44, 46) is made of a material or has a coating   made of a material facilitating the flow of concrete.   10. Installation according to one of claims 1 to 9,   characterized in that the end shaping device (42, 44, 46) has a lower height (H2) than that (HI1)   of the mold element over the rest of its length.   11. Installation according to one of claims 1 to 10,   characterized in that it comprises a compacting device (120) capable of conforming and compacting the top face (112) of the molded elements (Pl, P2) in the region of the devices   end conformers (42, 44, 46).   12. Installation according to claim 11, characterized in that the compacting device (120) comprises a lifting frame (122) pivotally mounted relative to the movable assembly (18) between a raised position of rest and a position lowered from work.   13. Installation according to claim 12, characterized in that the lifting frame (122) carries two parallel tubes (128), arranged horizontally and transversely to the direction of movement of the moving element, these tubes being adapted to be animated by a reciprocating movement by means of an eccentric motor (130), said tubes both coming to bear, in the working position, on top of the mold elements, in line with the devices   end conformers (42, 44, 46).   14. Device according to one of claims 12 and 13,   characterized in that the lifting frame (122) is pivotally mounted (124) either directly on the mobile assembly (18),   either on a carriage coupled to said equipping.   15. Device according to claim 13, characterized in that the two tubes (128) are articulated with two end levers (134, 136) to form a deformable parallelogram, each lever being articulated on the frame and one (134 ) of the two levers being further connected to the eccentric (132) by a link (146).   16. Device according to claim 14, characterized in that the tubes (128) are articulated to the end levers (134, 136) by pins (138) comprising springs (148) and in that the end levers (134 and 136) are themselves articulated to the lifting frame (122) by connections   with ball joint (158) on axes (140, 142) provided with springs (152).