Casing-device For The Reinforced Or Prestressed Concrete Flange Of A Girder

Abstract

A casing-device with numerous applications and varying sizes for the lower reinforced or prestressed concrete flange of a girder. Said flange has a substantially rectangular or square section and is cast independently of the girder's web. Said device comprises side-elements with side-sections and a casing soffit with articulated soffit-sections allowing the realization of said flange with a vertical upward or downward deflection. Said side-sections are rigid and weighty in order to facilitate their clamping against the soffit-sections and the tightness between these two parts.

Description

This invention relates to a casing-device having numerous applications and varying size for the reinforced or prestressed concrete lower flange of a girder. Said flange has a rectangular or square section and is cast independently of the girder's web.

Known casing-devices for the realization of such a flange comprise side-moulds and a soffit with articulated sections, allowing to realize a flange having a vertical down or upwards deflection. The side-moulds are generally fixed to the soffit by means of through-bolts. For that reason, the soffit-sections present rows of bond holes for the side-sections, so as to make possible the production of girder-flanges with varying width. Consequently, when a flange having more than the minimum width is to be realized, the bond holes situated between the side-sections have to be plugged.

In order to avoid these bond holes, nippers with rather long lever arms are used to produce an effective clamping of the side-moulds against the soffit-sections. Such a lever arm makes the effective clamping force of the side-sections against the soffit-sections relatively small compared to the force required to clamp the nippers on these soffit-sections.

Thus, the known casing-devices have several disadvantages resulting from slow assembling, due to the aforesaid bond holes or to the ineffective clamping of the side-moulds against the soffit-sections when using said nippers.

This invention concerns a novel casing-device, which allows to overcome the aforesaid disadvantages of the known devices.

In a casing-device according to the invention, the side-sections are rigid and weighty, in order to facilitate their clamping against the soffit-sections and the tightness between these two parts.

Each side-section comprises preferably at least one concrete prism.

Each side-section advantageously lays on the corresponding soffit-section with its inner and outer edges only. Thus, a maximum unit-clamping of this inner edge of the side-section on the soffit-section is achieved. In order to avoid the risk of outflow of the cement grout between the soffit-section and the inner edge of the side-section, the device comprises a lower longitudinal tightness joint, which is preferably compressible and bevelled.

According to a particularity of the novel device, the inner side of each prism is fitted with the aforesaid lower tightness joint and further with an upper longitudinal and preferably bevelled bar, sliding vertically, and with at least one longitudinal intermediate block, these three elements being tightly applied the one to the other. This particularity allows the realization of sides having different heights, by replacing the intermediate block only.

According to another particularity of the novel device, an additional tightness clamping is achieved by means of press-screws, but only at the ends of the side-sections, at the openings between the soffit-sections. These openings are necessary to allow the translation of adjoining casing-parts. Such an additional clamping needs neither holes in the soffit-sections, nor longarmed nippers, nor intermediate clamping-points whatsoever.

In order to assure the casing soffit continuity, each opening between the soffit-sections is obturated by a large, interchangeable and compressible soffit-joint, which extends substantially between the alignment of the side-sections. This soffit-joint is inserted between the soffit-sections in a precompressed or pretensioned state.

In order to assure the continuity of the side-profiles, each opening between the side-sections is obturated by a compressible wide side-joint presenting the same vertical inner section as the side-sections. This side-joint is inserted between the side-sections in a precompressed or pretensioned state.

According to another characteristic of the novel device, translation of the side-sections is operated by transversal threaded rods, located in the lower part of the openings between the soffit-sections and drawing the corresponding ends of the side-sections through slippers. These threaded rods are preferably operated in synchronism on the whole length of the casing by two separate synchronizing mechanisms, which are located on each side of this casing, and which can be, in their turn, synchronized.

The novel device gives the possibility to form with the soffit- and side-sections a vertical Cantilever system. In this case, one soffit-section out of two is supported by a pair of vertically movable jacks, assembled in two systems. The first of these systems is used to adjust the vertical polygonal shape of the casing by an individual action on each jack, the second system is intended for the withdrawal or the replacement of the whole casing, without changing its aforesaid polygonal shape, by a synchronized action on all the jacks. The jacks situated opposite each other in the first-mentioned system are preferably synchronically operated.

The casing supports, particularly the above-mentioned jack-pairs, are advantageously mounted on trucks allowing a longitudinal translation of the whole casing without change in its vertical polygonal shape. This characteristic allows to increase the utilization rate by discharging a cast flange before it can be transported.

Other details and particular features of the present invention will appear in the following description with reference to the accompanying drawings which give, by way of example only, an embodiment of the device according to the invention.

In these drawings:

FIG. 1 is a diagrammatic elevation of an embodiment of a casing-device according to the invention, in a horizontal position;

FIG. 2 is a similar diagrammatic elevation of a device for the realization of a girder-flange with a downward deflection;

FIG. 3 is also a similar diagrammatic elevation of a device for the realization of a girder-flange with an upward deflection;

FIGS. 4A, 4B, and 4C are partial longitudinal elevations of the casing-device;

FIG. 5 is a half-cross section of the device in lower position;

FIG. 6 is a half-cross section of the device in upper position;

FIG. 7 is a horizontal section of the threaded rod of a jack of the device, along the line VII--VII of FIG. 5;

FIG. 8 is a partial longitudinal section of the device, along the line VIII--VIII of FIG. 5;

FIG. 9 is a cross section of a truck of the device, along the line IX-IX of FIG. 8;

FIG. 10 is a partial longitudinal section of the device, along the line X-X of FIG. 5;

FIG. 11 is a horizontal section of the device along the line XI--XI of FIG. 10;

FIG. 12 is a partial longitudinal section of the device, along the connecting joint between two soffit-sections;

FIG. 13 is an elevation of a support for the soffit-sections;

FIG. 14 is another elevation of a soffit-section;

FIG. 15 is a vertical cross section of a soffit-section, along the line XV--XV of FIG. 14;

FIG. 16 is an elevation of a side-section;

FIG. 17 is a cross section of a side-section;

FIGS. 18, 19 and 20 are horizontal sections of a side-section along respectively the lines XVIII--XVIII, XIX--XIX and XX--XX of FIG. 17;

FIGS. 21A-21E show how to realize side-sections of different heights;

FIG. 22 is a partial cross section of the device between two soffit-sections and the corresponding side-sections;

FIG. 23 is a partial longitudinal section of the device along the line XXIII--XXIII of FIG. 22;

FIG. 24 is a partial horizontal section of the device along the line XXIV--XXIV of FIG. 22.

In these figures, same reference numerals refer to similar elements.

The shown device is used to realize a casing having numerous applications and varying dimensions for the lower reinforced or prestressed concrete flange of a girder. Such a device is used when the lower flange, which has a substantially rectangular or square section, is cast independently of the girder's web, i.e. not simultaneously with it. The considered casing-device comprises essentially a casing soffit and side elements.

The casing soffit comprises several successive articulated longitudinal elements 1. The sides are formed of the same number of side-sections 2 and 3 respectively aligned along each side of the soffit-sections. Thus each soffit-section 1 supports two side-sections 2 and 3 parallel to its longitudinal edges and symmetrically to the vertical median plane of the device.

The soffit-sections 1 and the side-sections 2 and 3 form vertically a Cantilever-system, which gives the possibility to realize the lower flange of the girder with an up or downward deflection. Such a Cantilever-system is shown in the FIGS. 2 and 3.

In the shown embodiment, each soffit-section 1 comprises a flat metal plate 4 without any perforation. The corresponding side-sections 2 and 3 lay upon the soffit-plate 4 with their inner edges.

The soffit-plate 4 is attached to cross-pieces 5 constituted of angle-irons. The crosspieces 5 are fixed on two stringers 6, formed of I-shaped girders. These stringers 6 are fastened to plates 7, laying on shock-absorber blocks 8, which are supported by the supports of the device. The shock-absorber blocks 8 constitute elastic supports for the whole of the soffit-sections 1 and the side-sections 2 and 3.

Each support for a soffit-section 1 and the corresponding side-sections 2 and 3 is essentially formed of two jacks 9 and 10 which can be mechanical jacks. These jacks 9 and 10 are of the "vertical movement" type.

Each jack 9 comprises a vertical threaded rod 11 which can move up or downwards along its longitudinal axis. A plate 12 is welded on the upper end of the threaded rod 11 and bears the corresponding shock-absorber block 8.

Each threaded rod 11 is screwed in a threaded pinion 13 which lays on a horizontal frame 14 through an antifriction disc 15.

The threaded pinion 13 comprises a wheel 16 which enables it to be rotated, in order to assure the vertical movement of the corresponding threaded rod 11.

In the chosen example, each threaded pinion 13 presents a toothed-wheel 17 forming a chain-wheel. Thus, the threaded pinions 13 placed symmetrically to the vertical median plane of the device and facing one another can be synchronically operated by means of a linking chain 18, mounted on their toothed-wheels 17.

In order to maintain each threaded rod 11 of every jack 9 in position, after its height-adjustment, the lower end of each rod 11 is provided with a counternut 19 comprising a control-wheel 20. The counternut 19 enables a firm clamping of an elastic blocking-disc 21 against the aforesaid frame 14.

This frame 14 is essentially constituted of stringers and crosspieces. The stringers are formed of two U-shaped irons 22, connected to one another by an upper plate 23 and a lower plate 24, both welded to their flanges. The crosspieces are constituted each of two other U-shaped irons 25.

Each threaded rod 11 of every jack 9 goes through circular holes presented respectively by the antifriction disc 15, the plates 23 and 24 and the flexible disc 21. The threaded rod 11 extends between the U-shaped irons 22 of the corresponding stringers as well as between the U-shaped irons 25 of the corresponding crosspiece.

The jacks 9 are operated two by two by hand. They are used to adjust the vertical polygonal shape of the casing constituted by the soffit-sections 1 and the side-sections 2 and 3. In other embodiments, said jacks 9 can be electromechanically operated, individually or all together.

Each jack 10 comprises a vertical threaded rod 26, which can rotate around its longitudinal axis without sliding along it.

Each threaded rod 26 is screwed in a threaded block 27 welded between the corresponding U-shaped irons 25 of the aforesaid frame 14.

Each threaded rod 26 is operated by a spiral gear 28, which is fixed to a nave 29, welded on the threaded rod 26 and engaged with an endless screw 30, which assures its rotation.

The nave 29 of each threaded rod 26 lays on another horizontal frame 31 through an antifriction disc 32. The lower end of each threaded rod 26 bears a disc 33 maintained by a pin 34.

Each frame 31 comprises stringers and crosspieces. The stringers are constituted of two U-shaped irons 35 connected to a lower plate 36. Each crosspiece comprises two U-shaped irons 37 forming a box.

Each frame 31 is mounted on a truck 38 movable along the vertical median plane of the device. The truck 38 comprises a frame formed of two stringers, each constituted of two U-shaped irons 39, braced by an upper plate 40 and a lower plate 41. In the chosen example, the frame 31 lays with its upper plates 36 on the upper plates 40 of the two said stringers and is fastened to them. The stringers of the truck 38 bear at their ends, axle-plates 42 mounted on two pairs of wheels 43 rolling on rails 44 parallel to the aforesaid vertical median plane.

Thus, the trucks 38 give the possibility of a longitudinal translation of the whole casing without any change in its vertical polygonal shape.

Each threaded rod 26 passes through the holes existing in the antifriction disc 32 and the plates 36, 40 and 41. It extends further between the U-shaped irons 35 of the corresponding stringer and between the irons 37 of the corresponding crosspiece of the frame 31, as well as between the irons 39 of the corresponding stringer of the truck 38.

The jacks 10 are synchronically operated by an electromechanical device. They serve to withdraw or to replace the whole casing without any change in its vertical polygonal shape. Thus, the endless screws 30, which are located on one side of the casing constitute a single shaft. The two shafts formed by the endless screws 30 and located respectively on each side of the casing are connected mechanically by driving-chains 45, each of which being mounted on two chain-wheels 46 and 47 fixed on the aforesaid shafts. The driving-chains 45 and the chain-wheels 46 and 47 corresponding to a soffit-section 1 are advantageously equidistant to the jack-pairs 10 of this soffit-section, as shown on FIG. 13. One of said shafts is further coupled with an electrical motor (not shown) which assures the simultaneous action of the jacks 10.

Two successive soffit-sections 1 are articulated the one with respect to the other, therefore the stringers 6 corresponding to these soffit-sections 1 bear, two by two, brackets 48 and 49 placed side by side and presenting coaxial openings, through which pivots 50 are passing, lined up along aforesaid transverse axis.

In order to assure the soffit continuity, each opening between two successive soffit-sections 1 is plugged by a wide, interchangeable soffit-joint 51, which consists of a compressible material and extends between the alignments of the corresponding side-sections 2 and 3. This soffit-joint 51 is inserted between the soffit-sections 1 in a precompressed state.

Each soffit-joint 51 in fact forms an inverted embossed element having longitudinal and transversal lower clamps. The soffit-joint 51 is compressed or released therefore using through bolts 52 passing through the longitudinal clamp openings.

When a soffit-joint 51 is introduced between adjoining soffit-sections 1, it is substantially compressed to a maximum by the corresponding bolts 52 and is inserted in this state between the soffit-plates 4 of these soffit-sections. The insertion of the compressed soffit-joint 51 is carried on until its edges press against the plates 53, welded on the respective soffit-plates 4 and the clamps of said soffit-joint 51 go into touch with the hook-shaped stops 54 also fixed on the corresponding plates 53. When the compressed soffit-joint 51 has reached its lowest position, where its upper face is in the prolongation of those of the soffit-plates 4, the joint is released and is so inserted between the soffit-sections 1, being flexibly applied in particular against these soffit-plates 4 and maintained in this position during a change in the relative positions of said soffit-plates 4 or of the soffit-sections 1. It should be noted, that the soffit-joint 51 presents holes 55 extending all over its length and making its compression easier.

According to the inventive idea, each side-section 2 or 3 is rigid and weighty. In the considered example, each side-section 2 or 3 comprises a reinforced concrete prism 56. The prism 56 has substantially a parallelepipedic shape, but presents further a lower inside projecting edge 57. The projecting edge 57 is reinforced by an U-shaped iron 58, with a height corresponding to the minimum height of the casing to be realized.

Each concrete prism 56 bears a half-opened shaped piece 59, fixed on its outer lower edge and realizing a longitudinal slot, opened downwards. Wooden blocks 60 can be fixed on the shaped piece 59 by screws 61 screwed in nuts 62 located in the aforesaid slot and sliding in it to adjust their position.

Each concrete prism 56 is equipped under its projecting edge 57 and its U-shaped iron 58 with a longitudinal lower tightness-joint 63, which consists of a compressible material, such as rubber or similar synthetic matter. This tightness-joint 63 has preferably bevelled edges and turns its largest face downwards.

Each concrete prism 56 achieved in this manner lays only with its lower tightness-joint 63 and its outer blocks 60 on the corresponding soffit-sections 1. More generally, the prism 56 is supported by the corresponding soffit-section 1 only with its inner and outer lower edges, in order to realize a maximum unit-clamping of the side-section 2 or 3 on this soffit-section 1.

Above its projecting edge 57, each concrete prism 56 presents, on the one hand, horizontal and transverse cylindric openings 64 extending between its outer and inner faces, and, on the other hand, vertical slots 65 located at its lower face and communicating with said openings 64.

In the vertical slots 65 of each concrete prism 56 are located half-opened vertical shaped pieces 66, between which blocking masses 67 of mortar are placed. Each shaped piece 66 forms actually a slide, opened downwards. On each shaped piece 66 boltheads 68 are welded, extending horizontally through the cylindrical openings 64 to the outer side and bearing nuts 69 screwed on the prism with interposed discs 70.

The slide formed by each shaped piece 66 is used for the vertical sliding of a metal sliding-block 71, having a horizontal cross section which corresponds to the transversal inner section of the shaped piece 66.

Each sliding-block 71 bears an angle-iron 72 fixed by means of a screw 73 passing through the slit of the corresponding shaped piece 66. The angle-iron 72 is equipped with an upper longitudinal bar 74, which delimits upwardly the inner height of the casing to be realized and is made, for example, of hard rubber or of a similar synthetic matter. The upper bar 74 is further bevelled and turns its largest face downwards.

Sliding of each sliding-block 71 allows to adjust the height-position of the upper continuous bar 74, according to the inner casing height to be realized. This upper bar is maintained in position after its adjustment to the wanted height, by means of one or more intermediate blocks 75, placed between this bar and the U-shaped iron 58 of the projecting edge 57 of the concrete prism 56. This or these intermediate blocks 75, for example wooden blocks, are further provided with inner tubes 76, allowing it or them to be held around a spline 77 of the upper flange of the U-shaped iron 58 and in an appropriate cavity in the upper bar 74. It should be noted that the upper bar 74 and the intermediate block or blocks 75 corresponding to the different shaped pieces 66 are clamped against the U-shaped iron 58 by a press-screw 78 screwed in a threaded block 79 and resting on the sliding-block 71 through one or several shaped pieces 80 fitted in the slide of this shaped piece 66 and corresponding to the intermediate block or blocks 75. The threaded block 79 is removably mounted on the upper end of the corresponding shaped piece 66, for example by a pin 81.

FIG. 21 shows various embodiments of the casing realized with the same concrete prism 56, but using one or more intermediate blocks 75 and one or more corresponding shaped pieces 80.

Each side-section achieved in this manner and disposed on the corresponding soffit-section 1 lays on the latter only by the action of its own weight. No mechanical clamping of each side-section against the soffit-section is required. An additional tightness-clamping is nevertheless achieved, only at the ends of successive side-sections, opposite the openings between the corresponding soffit-sections, but without any perforation of the soffit-plates 4 and without any intermediate clamping-points on these side-sections.

Each opening between the successive side-sections is closed by a wide side-part 82 of compressible material such as rubber or similar synthetic matter. The side-part 82 has the same vertical inner section as the adjoining side-sections and is inserted between these in a precompressed or, in some cases, a pretensioned state.

As shown on the last figure, each side-part 82 may present a shape similar to that of the aforementioned soffit-sections. The clamps of these side-parts 82 have also similar holes passed through by the corresponding bolts 83. The clamps may be brought together by the latters at the maximum compressibility of the side-part 82. The side-part 82 is inserted in this highly compressed state between the two corresponding side-sections, until its edges are applied against the vertical angle-irons 84, fixed to those side-sections and its clamps are in touch with the hook-shaped stops 85 fixed to these angle-irons 84. When the insertion of the side-part 82 has reached its limiting position described hereinbefore, the bolts 83 tying its clamps together are released. Thus the side-part 82 is flexibly applied against the corresponding side-sections and maintained in this position during the change in their relative positions. The inner vertical section of the side-part 82 and the adjoining side-sections are then aligned.

The side-sections 2 and 3 simply laying on the soffit-sections 1 are adjustable with regards to the vertical, the longitudinal and the median plane of the device. This adjustment is easily achieved by the simultaneous sliding of the side-sections on the soffit-sections under the action of operating means placed between the latter.

The adjoining side-sections located at the same side of the median plane of the device are equipped with at least one driving element. In the considered embodiment, this driving element is constituted of an U-shaped iron 86 fixed to the concrete prism 56. The U-shaped irons 86 of two successive side-sections are projecting one to the other between these irons and in the same plane.

The U-shaped driving-irons 86 of successive side-sections are connected mechanically to a slipper 87 formed of an I-shaped girder sliding on the edges of the soffit-plates 4 of the corresponding soffit-sections 1. For this purpose, the upper flange of the slipper 87 presents on each side of its web two identical openings and bears, opposite to these, two welded screwnuts 88. Screws 89 are screwed in the nuts 88 and pass through the above mentioned openings in such a manner, that their lower ends enter through discs 90, for example rubber-discs, into the corresponding openings of the respective U-shaped iron-webs 86.

In order to be guided along the edges of the floor-plates 4 of the two corresponding soffit-sections 1, each slipper 87 comprises a guide 91 fixed on its lower flange. In the chosen example, the guide 91 consists of an upper plate 92, a lower plate 93 and a connection-block 94. The plates 92 and 93 are disposed on each side of the edges of the soffit-plates 4 and are rubbing against the latters through layers 95 of an antifriction material.

The guide 91 of each slipper 87 bears a clamp 96 extending downwards and provided along its lower edge with a sleeve-nut 97, to which a transverse threaded rod 98 is screwed. Rotation of the threaded rod 98 causes a sliding of the whole slipper 87 and an identical shifting of the corresponding side-sections.

Each threaded rod 98 controlling the transversal shifting of the corresponding side-sections extends at the lower part of the opening between the corresponding soffit-sections. This rod 98 is set in a bearing 99 fixed to the corresponding angle-irons 5 of the supports of these soffit-sections. Said threaded rod 98 bears a welded nave 100, on which a spiral gear 101 is locked, engaged with an endless screw 102.

The endless screws 102 of all the threaded rods 98, corresponding to the side-sections situated on each side of the casing, are all placed on the same driving-shaft, so as to be driven in synchronism. The two driving-shafts of the two series of endless driving-screws 102 are further driven under the control of an appropriate synchronization-mechanism, resulting in a synchronical drive.

Thus, the distance-adjustment of the side-sections is easily and simultaneously achieved on each side of the vertical median plane of the device.

The present invention is obviously not limited to the shown embodiment. Many modifications can be made in the form, the arrangement and the structure of some of the elements, which take place in the realization thereof, according to the invention, provided that these modifications are not in contradiction with the content of any of the following claims.

Claims

I claim:

1. A casing-device for manufacturing the lower reinforced or prestressed concrete flange of a girder, said flange having a substantially rectangular or square section and being cast independently of the girder's web, said casing device comprising:

successive soffit-sections (1) articulated to one another, each having an upper metal plate (4),

means for supporting one soffit-section (1) out of two, comprising jacks (9) for giving said soffit-section (1) a predetermined inclination or for arranging it horizontally, in order to allow the production of said lower flange with a vertical upward-or downward-deflection,

a frame (14) for carrying said jacks (9),

means for supporting said frame (14), comprising other jacks (10) for moving vertically said frame (14),

means for actuating said last-mentioned jacks (10) in synchronism,

successive side-sections (2 and 3) respectively carried without clamping by the upper plates 4 of the soffit-sections (1) on both sides thereof, each side-section (2 or 3) comprising a weighty concrete prism (56) with a metallic inner side of regulable height and bearing inwardly on the upper plate (4) of the corresponding soffit-section (1), in order to ensure the tightness between said side-section and said soffit-section,

means for moving the side-sections (2 and 3) transversely on the soffit-sections (1), in order to regulate the distance between said side-sections,

compressible soffit-joints (51) extending between the soffit-sections (1), substantially between the alignment of the side-sections (2 and 3), and

compressible side-joints (82) extending between the side-sections (2 and 3), above said soffit-joints (51).

2. A casing-device for manufacturing the lower reinforced or prestressed concrete flange of a girder, said flange having a substantially rectangular or square section and being cast independently of the girder's web, said casing-device comprising:

successive soffit-sections (1) articulated to one another, each having an upper metal plate (4),

means for supporting one soffit-section (1) out of two, comprising jacks (9) for giving said soffit-section (1) a predetermined inclination or for arranging it horizontally, in order to allow the production of said lower flange with a vertical upward- or downward-deflection,

a frame (14) for carrying said jacks (9),

means for supporting said frame (14), comprising other jacks (10) for moving vertically said frame (14),

means for actuating said last-mentioned jacks (10) in synchronism,

successive side-sections, (2 and 3) respectively carried without clamping by the upper plates (4) of the soffit-sections (1) on both sides thereof, each side-section (2 or 3) comprising:

a weighty concrete prism (56),

a longitudinal iron (58) fixed to a lower projecting edge (57) of said prism (56) and corresponding substantially to the minimum height of the flange to be manufactured,

a lower longitudinal tightness joint (63) preferably bevelled, arranged under said iron (58) and bearing on the upper plate (4) of the corresponding soffit-section (1),

at least one metallic intermediate block (75) bearing on said iron (58) in alignment therewith,

an upper longitudinal bar (74) sliding vertically alongside the concrete prism (56) and bearing on said iron (58) or said block (75) and determining the height of the casing,

means for tightening together said iron (58), said intermediate block (75) and said bar (74),

means for moving the side-sections (2 and 3) transversely on the soffit-sections (1), in order to regulate the distance between said side-sections,

compressible soffit-joints (51) extending between the soffit-sections (1), substantially between the alignment of the side-sections (2 and 3), and

compressible side joints (82) extending between the side-sections (2 and 3), above said soffit-joints (51).

3. A casing-device according to claim 2 in which each side-section (2 or 3) rests on the corresponding soffit-section (1) only with its lower tightness joint (63) fixed to its inner edge (57) and with its outer edge, in order to achieve a maximum unit clamping of said inner edge on said soffit-section (1).

4. A casing-device according to claim 3 in which an additional tightness clamping is achieved by means of press screws (89), only at the ends of the side-sections (1), opposite the openings between the soffit-sections (1), without any perforation of said soffit-sections (1) nor intermediate clamping points on said side-sections (2 and 3).

5. A casing-device according to claim 1 in which the compressible soffit-joints (51) are interchangeable and inserted between said soffit-sections (1) in a precompressed or pretensioned state.

6. A casing-device according to claim 1 in which the compressible side-joints (82) are interchangeable and inserted between said side-sections (2 and 3) in a precompressed or pretensioned state.

7. A casing-device according to claim 1 in which the means for moving the side-sections (2 and 3) transversely on the soffit-sections (1) comprises transversal threaded rods (98), located in the lower part of the openings between the soffit-sections (1) and drawing the ends of the side-sections (2 and 3) by means of slippers (87 to 97).

8. A casing-device according to claim 7, in which the threaded rods (98) are operated in synchronism on the whole length of the casing and separately on each side of this casing by two synchronizing mechanisms.

9. A casing-device according to claim 8, in which said two synchronizing mechanisms are also synchronized.

10. A casing-device according to claim 1, in which the jacks (10) used for the withdrawal or the replacement of the whole casing are mounted on trucks (38) allowing the longitudinal shift of said whole casing without any change in its vertical polygonal shape.