FR3100040A1 - Method of assembling the reinforcing cage and the reinforcing cage element to implement said method - Google Patents

Abstract

The present invention relates to a method of assembling a reinforcing cage in which: a) there is provided a plurality of reinforcing cage elements (26, 28) extending between two ends, each of the elements (26, 28). ) comprising a plurality of metal rods (38, 38 ') parallel to each other, and transverse wires (42; 42') for maintaining said metal rods (38; 38 ') in a fixed position; b) said cage elements (26, 28) are suspended successively one above the other in order to be able to connect at least part of said rods (38, 38 ’). In step a), external plates (46, 48) are welded against the rods (38 ') in said one of said ends, and internal plates (52, 54) against the rods (38) in said other ends, so as to be able to adjust, in step b) said facing internal (52, 54) and external (46, 48) plates; and in step c) at least one screwable element (58) is engaged through said internal (52, 54) and external (46, 48) plates. Figure to be published with the abstract: Fig. 4

Description

Rebar cage assembly method and rebar cage member for implementing said method

The present invention relates to a method for assembling reinforcement cages inside boreholes.

The invention relates to a method of assembling a reinforcing cage also in any vertical formwork, for example a working tube for a soil displacement pile. In the rest of the description, “drilling” will be used to designate either the wall of an excavation or the working tube.

The present invention also relates to reinforcing cage elements or reinforcing cage sections to implement this method.

It should be noted that “section of reinforcement cage” and “reinforcement cage element” will be used interchangeably in the text.

The reinforcement cages are made of steel and they are assembled to be lowered inside sometimes deep boreholes before being embedded in concrete.

The depth of the drillings requires lowering the reinforcement cage as it is assembled. To do this, we provide reinforcement cage elements, of general shape cylindrical extending between two ends opposite each other, over a length usually less than 16 m. The parts making up the cage are in fact made or produced in the factory and then transported to the site. The indicative length of 16 m, satisfying the road gauge,may be reduced when the air height above the borehole is limited and/or by the height under the hook of the handling machine. Alternatively, the factory can be a cage manufacturing bench installed on site. Each of the elements comprises a plurality of metal rods extending parallel to each other at a distance from each other around a central space and this, from one of said ends to the other. When the cage elements are of rectangular section, the rods are held in a fixed position relative to each other by means of metal frames made of shaped wires, and welded transversely around the rods. The frames define a mean plane substantially perpendicular to the longitudinal direction of the cage element and they are spaced closer and closer between the two opposite ends of the element. Usually, at least one of the ends does not have frames over a length at least equal to 50 cm.

According to the usual assembly method, a first cage element is first suspended in the borehole and is held in support on the upper edges of the borehole so that its upper end emerges. Thus, the rods of this upper end are devoid of metal frames and a second cage element is suspended above it, using a handling device, to bring it down again so that the free rods of the upper end of the first cage element engage along the rods of the lower end of the second cage element inside the metal frames of the latter.

Then, two by two of the rods extended along each other are connected by ligature and/or by welding so as to secure the two cage elements together.

Then the first cage element is released which rests on the second cage element and the two cage elements are lowered into the borehole by a length equivalent to the length of the second cage element before retaining the latter resting on the edges of the borehole in turn and so that its upper end emerges from it. In the same way, a third cage element is connected to the upper end of the second cage element.

The operation is repeated in successive steps until the bottom of the borehole is reached.

These cage elements are relatively heavy, sometimes a few tens of tons. The ligatures or welds of contiguous rods are operated by operators, and the relative movement of contiguous rods constitutes a risk for them. In addition, the adjustment of the rods relative to each other is imprecise and leads to a significant margin of error on the relative position of the cage elements. In addition, the intervention time to connect these rods together is relatively long.

The manufacturing tolerances of the cage elements are such that the rods may not be strictly contiguous but a few centimeters apart; one solution consists in dissociating a rod from the frames, on one or more levels, in order to be able to bring it closer to the rod which corresponds to it in the other element, and then to make the connection between the rods, then to reconstitute the connection with the frames ; another solution is to bring a metallic element into the gap, i.e. between the rods, and to weld these three elements, the two rods and the metallic element, which then become contiguous two by two.

Also, a problem which arises and which the present invention aims to solve is to provide a cage assembly method which not only makes it possible to connect the cage elements together in complete safety, but also in a precise manner and at a cost advantageous.

For this purpose, and according to a first object, there is proposed a method of assembling a reinforcement cage inside the borehole comprising the following steps: a) a plurality of cylindrical reinforcement cage elements s extending between two ends opposite each other, each of the elements comprising a plurality of metal rods extending parallel to each other, from one of said ends to the other, and transverse fastening wires for holding said metal rods in a fixed position and at a distance from each other around a central space; b) said cage elements are successively suspended one above the other so that the rods of one of said two ends extend respectively along the rods of the other of said two ends; c) successively connecting two by two at least part of said rods extended along each other to be able to suspend said cage elements to each other inside said borehole. In step a), external plates are welded against the rods opposite said central space in said one of said two ends, and internal plates applied against the rods towards the inside of said central space in said other said two ends, so as to be able to adjust respectively, in step b), said inner and outer plates facing each other; and in step c) engaging at least one screwable element through said facing internal and external plates.

Thus, a characteristic of the invention lies in the implementation of external and internal plates respectively welded to the rods of the two ends in predetermined positions as will be explained below in the following description. In this way, when said two ends are engaged one in the other, external plates and internal plates respectively come opposite each other and it is then easy to connect them together by means of a screwable element. It is then understood that a lower cage element can be suspended in the borehole, at the lower end of the upper element via only the welded plates and the screwed elements.

The assembly made up of the two plates and the screwed element that unites them is called a “lock”.

The minimum number of locks per assembly is three non-aligned locks; usually, there are four for a rectangular frame. The locks are not necessarily arranged at the same level.

It will be observed that the plates can be welded during the manufacture of the cage sections. The positioning of the external plates at one end of the cage sections and the internal plates at the other end is carried out precisely according to specifications. Therefore, the connection between the ends of the anchoring elements can be made according to predefined and precise dimensions. Furthermore, the in situ connection is made by engaging the screwable elements through the pairings of internal and external plates, which not only mitigates the risks for the operators but in addition is fast. The connection is thus made in a short time and therefore at an advantageous cost.

Thanks to the precision of the adjustments of the reinforcement cages between them, and also to the rigidity of their connection, they can be adjusted very precisely in a vertical direction in the borehole. Therefore, it is easy to provide reservations in the cages and to be assured of their vertical position afterwards.

According to a particularly advantageous characteristic of the invention, in step a), oblong orifices are made through said external plates and said internal plates, so that the oblong orifices of said external plates and the oblong orifices of said internal plates extend in substantially perpendicular directions. In this way, if the adjustment of the external and internal plates vis-à-vis presents a slight offset which it is impossible to correct by driving one of the cage elements with respect to the other, it will always be possible to engage the threaded rod of a screwable element at the intersection of the oblong orifices facing each other.

According to a first embodiment variant, in step a), said external and internal plates are welded respectively applied to two contiguous rods. Thus, the plates form a bridge between two contiguous rods and the oblong orifice is formed in the center of the plate so as to be able to engage the screwable element between the two parallel rods. In this way, one obtains a perfect support of the inner and outer plates respectively against their two contiguous rods, when operating the tightening of the screwable elements s .

According to a second variant embodiment, in step a) said external and internal plates are welded respectively on three consecutive rods. According to this second variant, two oblong orifices are then produced per plate and hence a better mechanical strength of the connection between the two cage elements is obtained. Such a variant embodiment is advantageous when the cage elements have significant weights.

Preferably, said one of said ends of each of said elements is devoid of transverse fixing wires. In this way, it is easy to come and engage the two ends of two cage elements one in the other, because the rods released from the transverse fixing wires come to engage laterally along the rods of the other end against the transverse fixing wires, as will be explained below.

Also, according to a particularly advantageous embodiment of the invention, in step a), cylindrical reinforcing cage elements of rectangular section are provided, and said transverse fixing wires form rectangular frames surrounding said rods, said frames being regularly spaced from each other from one of said ends to the other. The quantity of rectangular frames installed around the rods depends on the bearing resistances desired in fine. It will also be observed that connecting wires can also be installed inside the central space between opposite rods to further reinforce the reinforcement cage.

According to another object, there is proposed a cylindrical reinforcement cage element for the implementation of the assembly method as described above, said reinforcement cage element comprising a plurality of metal rods extending parallel to each other, from one of the two opposite ends of said element to the other, and transverse fixing wires to hold said metal rods in a fixed position and at a distance from each other around a central space. Said element further comprises external plates welded against the rods opposite said central space in one of said two opposite ends, and internal plates applied against the rods towards the inside of said central space in the other of said two ends.

Thus, and as explained above, an advantage of these cage elements is to be able to connect them together quickly, without damage to the operators and with great precision in order to then be able to lower them into the boreholes.

Preferably, said outer plates and said inner plates have oblong orifices, so that the oblong orifices of said outer plates and said oblong orifices of said inner plates extend in substantially perpendicular directions. Thus, a bad adjustment of the internal and external plates respectively with respect to each other, authorizes, despite everything and to a certain extent, the engagement of a screwable element.

According to a first variant embodiment, said external and internal plates are welded respectively applied to two contiguous rods.

According to a second variant embodiment, said external and internal plates are welded respectively applied to three consecutive rods

Other particularities and advantages of the invention will become apparent on reading the description given below of particular embodiments of the invention, given by way of indication but not limitation, with reference to the appended drawings in which:
is a general schematic view of the implementation of the assembly method according to the invention, according to a first phase;
is a partial schematic detail view of one of the elements shown in Figure [Fig. 1];
is a partial schematic detail view of another element shown in Figure [Fig. 1];
is a partial schematic cross-sectional view of the elements shown in Figure [Fig. 1], in a second assembly phase.

The figure shows a borehole 10 drilled in the ground 12. It extends from the surface 14 to the bottom 16 over a distance of approximately 50 m for example. The borehole 10 has two opposite edges 18, 20 in which are installed reinforced concrete guide walls 22, 24 precisely allowing these edges 18, 20 to be stabilized and to be able to be supported.

The figure also illustrates a first cylindrical reinforcement cage element 26 engaged in the borehole 10 and a second cylindrical reinforcement cage element 28 kept suspended above the first. These two reinforcement cage elements 26, 28 are of identical shape, the first 26 is kept suspended in the borehole 10 flush with the surface 14 by means of transverse rods 30 resting on the guide walls 22, 24, while the second 28 is held suspended from a sling 32 by means of a handling device, not shown. If the two reinforcing cage elements 26, 28 are of identical shapes, their constituent elements are not necessarily of the same size as will be explained below.

Cylindrical reinforcement cage elements are manufactured in the factory and are then generally transported by road, in situ for the assembly of reinforcement cages, in particular but not exclusively, diaphragm wall reinforcement cages.

The first cylindrical reinforcement cage element 26 has a first lower end 34 and a first opposite upper end 36. It extends for example over a length of 16 m. Also, it comprises a plurality of first metal rods 38 held parallel to each other around a first central space 40 by means of transverse wires 42, formed as a frame. The first metal rods 38 extend longitudinally from the lower end 34 to the opposite upper end 36. They are for example made of low carbon steel and they have ribs on the surface allowing better anchoring in the concrete. The transverse wires 42, also made of steel, have a diameter usually lower than that of the rods 38. Also, they are welded to the first rods 38.

For example, the metal rods 34 are spaced from each other by a distance of 20 cm, defining a cylindrical shape with a rectangular section of 80 cm by 120 cm for example. The transverse wires 42 formed as a frame each define mean planes substantially perpendicular to the rods 38 and they apply against the rods 38, towards the outside, opposite the first central space 40. The transverse wires 42 formed as a frame are for example spaced from each other in the longitudinal direction of the cylindrical reinforcement cage 26, also by a distance of 20 cm. They are then welded at each intersection with the rods 38. In this way, the first rods 38 are held in a fixed position relative to each other over the entire length of the cylindrical reinforcement cage element 26.

Furthermore, it will be observed that the first lower end 34 of the first cylindrical reinforcing cage element 26 is provided with transverse wires 42 formed as a frame up to the free end of the first rods 38. On the other hand, the first upper end 36 is devoid of transverse son 42 over a length of about 1 m. Also, the rods 38 have first free ends 44 extending vertically in the open air. This feature makes it easier to connect together the two cylindrical reinforcing cage elements 26, 28 as will be explained below.

The second cylindrical reinforcement cage element 28 is identical in shape to the first 26. Also, its various components will bear the same reference affected by a prime sign "'".

Thus, it has a second lower end 34' opposite a second upper end 36'. It also comprises a plurality of second metal rods 38' held parallel to each other around a second central space 40' by means of second transverse wires 42, formed as a frame. Also, the second metal rods 38 'are not necessarily of the same diameter as the first metal rods 38. They have for example a larger diameter.

In addition, the second lower end 34' is provided with second transverse wires 42' formed as a frame up to the free end of the second rods 38', and the second upper end 36' does not have a length of about 1 m. also. The second rods 38 thus have second free ends 44'. On the other hand, the second transverse wires 42′ formed as a frame can also have a larger diameter and also be distributed differently along the reinforcement cage element.

The details of the lower 34, 34' and upper 36, 36' ends of the cylindrical reinforcement cage elements 26, 28 will now be described, which are not shown in the figure. , and which allow their connection, with reference to the figures [Fig. 2] and [Fig. 3].

It will be recalled that the two cylindrical reinforcing cage elements 26, 28 are of identical shapes and consequently that the description of the first upper end 36 of the first cylindrical reinforcing cage element 26 applies to the second upper end 36'. of the second cylindrical reinforcement cage element 28, whereas the description of the second lower end 34' of the second cylindrical reinforcement cage element 28 applies to the first lower end 34 of the first cylindrical reinforcement cage element 26.

Thus, the figure shows in detail, seen from the outside with respect to the second central space 40', the second lower end 34' of the second cylindrical reinforcement cage element 28. It will be observed that the figure [Fig. 2] illustrates a single face of this second lower end 34', which has four of them, two by two opposite. The face opposite to that represented here is symmetrical with respect to a median plane and the elements which will be described are identical and also symmetrical.

We find in this figure, the second rods 38' parallel to each other and spaced from each other. There are also the second transverse wires 42' formed as a frame, up to the free end of the second rods 38'.

Also, during the manufacture of the cylindrical reinforcing cage elements 26, 28, two outer plates 46, 48 are welded applied and at the same level on two contiguous rods 38' and between two second transverse wires 42'. It will be observed that the only face illustrated in the figure has seven rods 38' defining the same plane, one central and two at the end, and that the two external plates 46, 48 are integral with the pairs of rods 38' respectively located between the central rod and those at the end. The number of rods is obviously not limiting. These outer plates 46, 48 are made of steel and they have a substantially rectangular shape. Outer plates 46, 48 bear tangentially against rods 38'. For a perfect weld, two weld beads are produced respectively on each side of the line of contact between the rod 38' and the plate 46, 48.

In addition, these two outer plates 46, 48 each have a longitudinal oblong orifice 50 extending in a direction substantially parallel to the rods 38'.

As indicated above, two other external plates, not shown, are welded on the face opposite to that shown in the figure. and in a symmetrical position with respect to a median plane.

We will now refer to Fig. showing in detail the first upper end 36 of the first cylindrical reinforcement cage element 26. There we find the first rods 38 and their first free end 44. A single first transverse wire 42 appears there, behind the first free ends 44.

Also, the figure shows here in detail, no longer seen from the outside with respect to the first central space 40, but seen from the inside, the first upper end 36 of the first cylindrical reinforcement cage element 26. As for the figure [Fig . 2], the figure [Fig. 3] illustrates a single internal face of this first upper end 36, which also has four, two by two opposite. The face opposite to that represented here is also symmetrical with respect to a median plane.

Also, in the same way, during the manufacture of the cylindrical reinforcement cage elements 26, 28, two internal plates 52, 54 are applied and at the same level on two contiguous rods 38. And in addition, the two internal plates 52, 54 are integral with the pairs of rods 38 respectively located between the central rod and those of the end. These two internal plates 52, 54 each have a transverse oblong orifice 56 extending in a direction substantially perpendicular to the rods 38.

Also, two other internal plates, not shown, are welded on the internal face opposite to that shown in the figure. and in a symmetrical position with respect to a median plane.

Have thus been described in detail, with reference to the figures and [Fig. 3], respectively, the second lower end 34' and the first upper end 36 as they appear in the figure [Fig. 1] in a phase where the second cylindrical reinforcing cage element 28 is suspended above the first 26, the second rods 38' and first rod 38 respectively facing each other.

As shown in figure , the second cylindrical reinforcement cage element 28 is then lowered by releasing the sling 32 so that the second lower end 34', forming the female part, fits over the first upper end 36 forming the male part.

More precisely, the first free ends 44 of the first rods 38 of the first upper end 36 engage laterally and respectively along the second rods 38' of the second lower end 34' and inside the second transverse wires 42 formed in frame.

Continuing the descent of the second cylindrical reinforcing cage element 28, the two outer plates 46, 48 respectively come opposite the two inner plates 54, 52. It will be observed that the same is true of the two pairs of opposite plates. of the other two opposite faces respectively of the upper end 36 and of the lower end 34'.

When the outer plates 46, 48 are facing or face to face with the two inner plates 54, 52, their respective oblong slots 50, 56 facing each other then extend crosswise.

Consequently, whatever the precision of the relative adjustment of the lower 34' and upper 36 ends, it is always possible to engage the threaded rod of a screwable element between the rods 38, 38' and across the two pairs. plates 46, 54; 48, 52.

We will now refer to Fig. thus illustrating the upper end 36 of the first cage element 26 connected to the lower end 34' of the second cage element 28.

We find in this figure the first rods 38 at the level of the upper end 36 of the first cage element 26 as well as the second rods 38' at the level of the lower end 34' of the second cage element 28; the first rods 38 extending along the second rods 38'. The transverse wires 42, 42' formed as a frame are shown in broken lines. We also find, on the one hand the two external plates 46, 48 welded against the two pairs of contiguous rods 38' of the lower end 34' by means of two first weld beads 55, and on the other hand the two plates internal 54, 52 welded against the two pairs of contiguous rods 38 of the upper end 36 by means of two second weld beads 57.

Thus, the two pairs of plates 46, 54; 48, 52 respectively opposite are traversed by a screwable element 58 having a threaded rod 60, a head 62 bearing against the internal plates 54, 52 and on the opposite side, a nut 64 bearing against the external plates 46, 48 Preferably, the threaded rod 60 is engaged from inside the cage so that the head 62 bears against the internal plates 54, 52 and the nut 64 bears against the external plates 46, 48. so it is easier to force the nut 64 to be screwed on from the outside of the reinforcement cage.

The nuts 64 are then screwed on by force to secure the two ends 36, 34'. It will be observed that the two pairs of opposite faces of these two ends 36, 34' are symmetrical to each other with respect to the median plane Pm, and that they are joined in the same way.

In this way, after the first upper end 36 illustrated in FIG. has been secured to the second lower end 34' as indicated above, the sling 32 carries the second cage element 28 substantially upwards in a first phase so as to suspend the first cage element 26 at the second end bottom 34' of the second cage element 28. Thus, the two cage elements 26, 28 are held together by the welded plates 46, 54 alone; 48, 52 and corresponding screw elements 58. In this way, the supports on the guide walls 22, 24 are released. The transverse rods 30 are then withdrawn and the assembly of the two cage elements 26, 28 is then lowered, by a pitch equivalent to the length of the cage element, in the borehole 10 so that the second free ends 44' in turn extend projecting from the surface 14.

The two cage elements 26, 28 are kept suspended in the borehole 10 by means of the transverse rods 30 resting on the guide walls 22, 24, and engaged through the second upper end 36'. Consequently, a third reinforcement cage element, not shown, can then be kept suspended from the sling 32 in order to be able to connect it to the second reinforcement cage element 28 in the same way as that described above for the first 26 and second 28 elements. It is then possible to install a plurality of reinforcing cage elements in this way. The number varies according to the depth of the borehole 10 and the length of the sections.

Such an assembly method is much faster than those implemented according to the prior art. It also involves much less risk for operators. And the adjustment of the reinforcement cage elements presents more precision.

Claims (10)

Method of assembling rebar cage inside drilling comprising the following steps:
- a) a plurality of cylindrical reinforcement cage elements (26, 28) extending between two mutually opposite ends (34, 36; 34', 36') are provided, each of the elements (26, 28) comprising a plurality of metal rods (38, 38') extending parallel to one another, from one of said ends (34; 34') to the other (36; 36'), and wires transverse fixing brackets (42; 42') for maintaining said metal rods (38; 38') in a fixed position and at a distance from each other around a central space (40; 40');
- b) the said cage elements (26, 28) are successively suspended one above the other so that the rods (38) of one (36) of the said two ends extend respectively along the rods (38' ) the other of said two ends (34');
- c) successively connecting two by two at least a portion of said rods (38, 38 ') extended along each other to be able to suspend said cage elements (26, 28) to each other inside said drilling (10)
characterized in that in step a), external plates (46, 48) are welded applied against the rods (38') opposite said central space (40') in said ones (34') of said two ends, and internal plates (52, 54) applied against the rods (38) towards the interior of said central space (40) in said other (36) of said two ends, so as to be able to adjust respectively, to the step b) said inner (52, 54) and outer (46, 48) plates facing each other;
and in that in step c) at least one screwable element (58) is engaged through said facing inner (52, 54) and outer (46, 48) plates. Assembly method according to claim 1, characterized in that in step a) oblong orifices (50, 56) are made through said external plates (46, 48) and said internal plates (52, 54), so that the oblong orifices (50) of said external plates (46, 48) and the oblong orifices (56) of said internal plates (52, 54) extend in substantially perpendicular directions. Assembly method according to Claim 1 or 2, characterized in that in step a) the said external (46, 48) and internal (52, 54) plates are welded respectively in contact with two contiguous rods (38, 38 '). Assembly method according to Claim 1 or 2, characterized in that in step a) the said external (46, 48) and internal (52, 54) plates are welded respectively on three consecutive rods (38, 38 '). Assembly method according to any one of Claims 1 to 4, characterized in that the said one (36; 36') of the said ends of each of the said elements (26, 28) is devoid of transverse fixing wires (42). Assembly method according to any one of Claims 1 to 5, characterized in that in step a) cylindrical reinforcement cage elements (26, 28) of rectangular section are provided, and in that the said transverse fastening wires (42; 42') form rectangular frames surrounding said rods (38, 38'), said frames being regularly spaced from one another from one of said ends (34; 34) to the other (36 ; 36'). Cylindrical reinforcement cage element for implementing the assembly method according to any one of claims 1 to 6, said reinforcement cage element (26, 28) comprising a plurality of metal rods (38; 38') extending parallel to each other, from one (34; 34') of the two opposite ends of said element to the other (36; 36'), and transverse fixing wires (42; 42') for maintaining said metal rods (38; 38') in a fixed position and at a distance from each other around a central space (40; 40');
characterized in that it further comprises external plates (46, 48) welded against the rods (38') opposite said central space (40') in one (34') of said two opposite ends , and internal plates (52, 54) applied against the rods (38) towards the inside of said central space (40) in the other (36) of said two ends. Cylindrical reinforcement cage element according to Claim 7, characterized in that the said external plates (46, 48) and the said internal plates (52, 54) present oblong orifices (50; 56), so that the oblong orifices of the said outer plates (46, 48) and said oblong orifices of said inner plates (52, 54) extend in substantially perpendicular directions. Cylindrical reinforcing cage element according to Claim 7 or 8, characterized in that the said external (46, 48) and internal (52, 54) plates are welded respectively on two contiguous rods (38; 38'). Cylindrical reinforcement cage element according to Claim 7 or 8, characterized in that the said external (46, 48) and internal (52, 54) plates are welded respectively on three consecutive rods (38; 38').