WO1984002369A1

WO1984002369A1 - Prefabricated concrete reinforcing element and a cassette for use in this element

Info

Publication number: WO1984002369A1
Application number: PCT/FI1983/000077
Authority: WO
Inventors: Pekka Jaervinen
Original assignee: Rake Oy
Priority date: 1982-12-07
Filing date: 1983-12-02
Publication date: 1984-06-21
Also published as: FI824194A0; FI824194L; EP0129572A1

Abstract

A prefabricated concrete reinforcing element with which a first phase concrete casting (24) is connected to another concrete casting part or other equivalent structure and possibly to its reinforcement parts (23). The reinforcing element comprises a plurality of uniformly spaced adhesion parts (1, 3) which have been fixed to a sectional sheet cassette (10; 10') in conjunction with holes (9, 9') or cut-outs thereof. The sectional sheet cassette (10; 10') leaves the joining adhesion parts (3) of the adhesion parts (1, 3) free from first-phase concrete casting (23) and keeps the joining adhesion parts (3) at a given mutual spacing. The sectional sheet cassette (10; 10') has a central groove facing the first-phase concrete pouring (24), confined by a bottom wall (6) and by bends (5) connecting this to the main wall (8) of the sectional sheet cassette (10; 10'). The depth of this groove is substantially equal to the dimension of the cassette (10; 10') determined by the side bends (2). The central groove is intended to be used in fixing the sectional sheet cassette (10; 10') on the wall of the first-phase concrete casting mould (12).

Description

PREFABRICATED CONCRETE REINFORCING ELEMENT AND A CASSETTE FOR USE IN THIS ELEMENT.

The present invention concerns a prefabricated concrete reinforcing element with which a first phase concrete cast is joined to another concrete-cast part or other equivalent structure and possibly to its steel reinforcing parts, said reinforcing element comprising a plurality of adhesion parts disposed in the reinforcing element, preferably at equal spacing, said adhesion parts having been attached to a sectional sheet cassette in conjunction with holes or equivalent cut-outs thereof, and the purpose of said sectional sheet cassette being to leave the joining adhesion parts of said adhesion parts free from first-stage concrete casting and to maintain said joining adhesion parts at a given spacing, and said sectional sheet cassette having a main wall and side bends.

In the Finnish patent application No. 814018 by the same applicant (filed December 11th, 1981), equivalent PCT application No. , a concrete reinforcing element substantially similar to that defined in the foregoing has been presented.

In the invention presented in the Finnish application mentioned, it has been considered novel that said base part is a sectional sheet cassette made of sheet steel or equivalent, and provided with apertures through which the adhesion parts made e.g. of bulb steel have been fixed in conjunction with the sectional sheet cassette. Moreover, in the Finnish patent application referred to above has been described a procedure for making the reinforcement junctures, in said procedure two concrete cast parts made at different phases are joined together and in which to the concrete casting part being poured is attached a particular prefabricated concrete reinforcing element, the adhesion steel parts of which affix the concrete reinforcing element to the part being cast first and said concrete reinforcing element being provided with a part which prevents the joining adhesion parts which form an extension to the adhesion steel parts or. their coupling parts from being covered under the concrete casting that is first carried out. As taught by the Finnish application No. 814018, in the reinforcing element manu¬ facturing procedure above defined it has been considered novel that for said concrete reinforcing element is used a sectional sheet cassette, having bent-off planes joining its lateral margins and which in the first casting phase protect the joining adhesion parts or their fixing parts, and that said bent-off planes of the sec¬ tional sheet cassette are bent to be substantially parallel to the side bends of the sectional sheet cassette, and thereafter the joining adhesion parts of the adhesion steel parts are bent to be substantially perpendicular to the wall of the sectional sheet cassette and are possibly attached to the steel parts of the further casting, or that subsequent to bending the bent planes, separate joining adhesion parts are affixed to the adhesion parts.

The object of the present invention is to accomplish improvements in the prefabricated concrete reinforcing elements described above. The sectional sheet cassette presented in the Finnish patent application mentioned above has substantially rectangular shape and it has comparatively wide main wall and side bends. In practice, a reinforcing element such as this is has been found to suffer e.g. from the drawback that the broad main wall tends to separate from the concrete casting when the cast mould is being torn off with great force from its connection with the element. Moreover, diffi- culties have arisen in the fixing of the concrete casting mould in conjunction with the reinforcing element in question. The fixing of the adhesion steel parts and of its joining adhesion parts to be in conjunction with the sectional sheet cassette also leaves room for improvement.

With a view to avoiding the drawbacks presented above and above all in order to improve the adhesion of the sectional sheet cassette part and of the concrete being cast, the invention is mainly characterized in that the sectional sheet cassette is provided with a central groove on the side of the first-phase concreting, defined by the bottom wall and by the bends connecting it to the main wall of the sectional sheet cassette, the depth of said groove being substantially equal to the dimension of the cassette determined by the side bends or slightly less, and that said central groove is of the kind that it is appropriate to be used in fixing the sectional sheet cassette to the wall of the casting mould for the first-phase concrete.

The sectional cassette of the invention has side flanges positioned inwardly obliquely with reference to the principal plane of the cassette, i.e., which are non-perpendicular; and has on the, preferably central, bottom groove of the cassette equivalent oblique side bends, whereby better adhesion than before to the con¬ crete cast is attained. In addition, in conjunction with the side bends of said bottom groove is formed an advantageous adhesion receptacle for the joining adhesion parts of the steels. Further- more, said bottom groove may be used advantageously in the fixing of the sectional sheet cassette in conjunction with the concrete casting mould e.g. with the aid of a nailing pistol. It is also an advantage of the sectional sheet cassette of the invention that it may be composed of one simple substantially U-shaped sectional sheet, of which two are set against each other, and of a planar sheet strip therebetween, these parts being affixed to each other e.g. by means of disk or point welding.

The invention is described in detail in the following by referring to certain embodiment examples presented in the figures of the attached drawing, the invention being in no way narrowly confined to their details.

Fig. 1 presents an axonometric projection of a concrete reinforcing element according to the invention.

Fig. 2 shows the cross section I-I of the concrete reinforcing element of Fig. 1.

Fig. 3 shows a cross section of the central part of the sectional sheet cassette of the reinforcing element of the invention. Fig. 4 presents the cross section of the sectional sheet cassette of a concrete reinforcing element according to the invention in the case that the sectional sheet cassette has been formed by combining a plurality of different partial sections by methods known in the art.

Fig. 5 presents a reinforcing element according to the invention installed in the concreting mould, where it has been connected to the other concrete reinforcements within the mould by methods known in the art.

Fig. 6 shows the same as Fig. 5, but later in time, when the mould boards have been removed and the joining parts of the reinforcing element of the invention have been bent to protrude, for the extension connection.

Fig. 7 shows the shape of the bulb steel cramp prior to its mounting in conjunction with the cassette.

Fig. 8 presents the bulb steel cramp, bent into shape, in which a permanent deformation is produced by which is achieved a pre-stress in the cramp which maintains it conjoined with the dovetail groove of the cassette.

Fig. 9 shows the shape of the buld steel configuration after it has been released from the pre-stress phase of Fig. 8.

The typical and essential components of the concrete reinforcing element of the invention are the main parts depicted in Fig. 1, that is, the adhesion steel parts 1, of which there may be an arbitrary number in the reinforcing element and which are intended to become joined to that concrete casting and to the concrete reinforcing steels, if any, contained therein in the mould of which the reinforcing element under consideration will be inserted; and a sectional sheet cassette Id manufactured from sheet steel by methods known in the art, said cassette by its shape supporting the adhesion steel parts 1 and to a sufficient degree preventing access of the

C_._*I first-phase concrete casting into the interior space of the reinforcing element, where the joining adhesion parts 3 are located. The joining adhesion parts 3 are integral extension parts of the adhesion steel parts 1 or adhesion steels subsequently connectable thereto by procedures known in the art.

The adhesion steel parts 1 and the joining adhesion parts 3 are made e.g. of bulb steel by bending, as has been done in Figs 1 and

_

2. The cassette 10 has been made of a thin, either plain or galvan- ized steel sheet by procedures known in the art into a section which is longitudinally rigid enough. This rigidity is ensured by means of bend planes 2 and 4 joined to the main wall 8 and by groove bends 5 and a groove bottom 6.

The cassette 10 has, by procedures known in the art, been provided with holes 7 and with holes 9,9' and 9". It may be noted concerning the location of the holes 9,9',9" and 7 in relation to each other that the holes 7 are located halfway between the lines of holes 9-9, 9'-9' and 9"-9", this being important in order that nailing with a hammer, or shooting of the nails 14, can be done without impediment from the parts 1.

A bulb steel assembly 1,3 bent by methods known in the art in the shape shown in Fig. 1 is inserted in the cassette 10 of the reinforcing element in the position of Fig. 1, in the following way. The bulb steel assembly 1,3 bent to the configuration of Fig. 7 is pushed into the cassette 10 through the holes 9,9',9" with the ends A and A' of the bulb steel assembly 1,3 ahead, and it is turned about 90 degrees, whereby the plane defined by the adhesion steel parts 1 of the bulb steel assembly 1,3 is substan¬ tially perpendicular against the main wall plane 8 of the cassette 10 and the joining adhesion parts 3 are substantially longitudinal to the cassette.

Thereafter, the joining adhesion parts 3 of the bulb steel assembly 1,3 are bent crosswise in the form of Fig. 8, for instance manually. A permanent deformation is thereby produced in the bulb steel, which will give rise to a compressive force between the ends A and A' of the joining adhesion parts 3. When following on the phase just described the joining adhesion parts 3 are returned towards their original position, as in Fig. 7, to the extent that the ends A and A' are spaced by the distance b indicated in the figure, the ends A and A' of the joining adhesion parts may be pressed into the space between the main wall planes 8 and the grooved bottom 6, whereby they come to lie against the grooved bends 5. The compress¬ ive force produced by the permanent deformation in the bulb steel assembly 1,3 between the ends A and A' and the form of the grooved bends 5 prevent the joining adhesion parts 3 of the bulb steel as¬ sembly 1,3 from falling out from the interior of the cassette 10.

In the following is described, with reference being made to Figs 3 and 5, the fixing of the cassette 10 in conjunction with the wall 21 of a concrete casting mould and the advantageous attachment of the cassette 10 to the first-phase concrete cast. As shown in Fig. 5, the cassette 10 is affixed by its grooved bottom 6 with a nail 12 with washer 14, to the wall 21 of the concrete casting mould. The opposite wall of the concrete casting mould has been indicated by the reference numeral 22 and the first-phase concrete casting by the reference numeral 24, and its steel inserts by the reference numeral 23. As can be seen in Fig. 5, the inclined walls 2 and 5 of the cassette 10 constitute such parts resembling a dove- tail joint which produce effective attachment of the cassette 10 in conjunction with the concrete 24 and in that connection prevent the cassette from being detached when the mould wall 21 is taken off the cured concrete 24.

Fig. 3 displays more closely an example of how the cassette 10 may according to the invention be fixed by its grooved bottom 6 in conjunction with the wall 21 of the concrete casting mould. In each hole 7 of the grooved bottom 6 has been inserted a plastic plug 20 with a hole 11. The plug 20 carries a larger diameter flange 13 securing it in conjunction with the hole 7. A nail 14 with washer 12 may be inserted into the hole 11 of the plug 20 and affixed either by a hammer or by shooting with a nailing pistol. In Fig. 3

C_. I is schematically presented the chuck 13 of the nailing pistol. In the manufacturing of the cassette 10 it should be kept in mind that the dimension C indicated in Fig. 3, i.e., the measure of the mouth of the central groove, is slightly larger than the chuck 13' of the nailing pistol or the head of the hammer. The hole 11 in the plastic plug 20 ensures the alignment of the nail 14 and facilitates the nailing, since the nail 14 may be placed in advance in the hole 11. When the mould board 21 is being taken off, the flange 13 of the plug 20 will fail because the mould board 21 has to be removed using comparatively great force and the plug 20 can pass through the hole 7, whereas the nail 14 remains conjoined to the mould 21. A "fuse" has been obtained In this manner, which in part ensures that when the mould board 21 is being pulled off the cassette 10 will positively remain inside the concrete 24, this being also ensured by the dovetail shape of the cassette 10, already described, and by the centrally located dovetail groove 5,6 which, as described in the foregoing, is also particularly advantageous in connection with the mounting of the cassette to the mould board 21.

In Fig. 4 is shown an alternative embodiment of the invention, according to which the sectional sheet cassette 10' is made of three separate parts, that is, of two identical parts placed against each other and which are sections with substantially U- shaped cross section and which comprise the main planes 8, the oblique side bends 2 described above, end bends 4, and inclined bends 5, outwardly directed side bends 16 connecting with the last-mentioned. Moreover, the assembly 10' includes a planar sheet strip 15, which is affixed e.g. by disk or point welds 25 to the side bends 16 of the U-shaped sections in the manner that the assembly 10' becomes symmetrical with reference to its centre plane T-T. The planar sheet strip 15 is fixed to said side bends 16 so that the marginal parts 17 of the strip 15 extend slightly over the inclined bends 5. The breadth of the sheet strip 15 has been indicated with D in Fig. 4.

In the following are presented the advantages of the concrete reinforcing element of the invention, in catalogue fashion:-

O PI "WΪPO^" - the invention ensures the fixing of the cassette 10; 10' in the concrete 24: this is accomplished by the inclined planes 2 of the cassette 10; 10' and by the dovetail shape of the central part 5,6;

- the cassette interrupts any sound bridge that may otherwise be formed in the junction;

- the cassette enables fixing to be accomplished with a nailing pistol;

- when the grooved bottom 6 is located slightly higher (dimension h' in Fig. 2) than the bend planes 4 and the cassette is being fixed to the mould, the grooved bottom 6 will be pressed against the mould board 21 and produce a pressing force also on the bend planes 2,4, which will be tightly urged against the mould board 23 and will prevent access of the concrete 24 to the interior of the cassette 10; 10' from the sides. This makes also possible the use of narrower bend planes 4 compared with prior art (no need for any sealing.effect);

- In the case of the assembly sheet cassette 10' of Fig. 4, it is possible by varying the breadth D of the sheet strip 15 to make available cassettes 10' of many different widths for different reinforcing applications. The marginal parts 4,2,8,5,16 are standard parts for all breadths. The groove bend 5 may also be perpendicular to the main wall plane 8, because the projecting flaps 17 of the strip 15 hold the ends of the joining adhesion parts 3 within the cassette 10'.

As shown in Fig. 6, the mould walls 21 and 22 of the first-phase concrete 24 have been removed after the concrete 24 has cured. The cassette 10 remains firmly inside the first-phase concrete 24 with its two dovetail joints. The cassette 10 keeps the adhesion steel parts 1' in their proper places, and after removal of the mould board 21 and 22, the joining adhesion parts 3' may be bent from the outwardly directed protective grooves of the cassette 10 into the position 3' seen in Fig. 6. Thereafter, the second phase

^< concreting may be carried out, to which the joining adhesion parts 3' become coupled. Moreover, the second phase concrete casting will become coupled with the outwardly projecting dovetail grooves of the cassette 10, and this contributes to better fixing to each other of the first phase and second phase concrete than before.

In Fig. 2 has been indicated as angle α the inclination of the bends 2 and 5 in relation to the position at right angles against the plane 8. In the invention, the angle may vary e.g. between 5 and 30 . Also angles outside this range may occasionally be used. The bends 2,4,5,6 and 8 need not be straight, and they may in some instances be curved, grooved, corrugated or provided with various projections, roughenings, e.g. with nailings pierced from within the cassette 10;10', these promoting the coupling of the cassette with the first phase or second phase concrete casting.

In the following are presented the claims, various details of the invention being allowed to vary within the scope of the inventive idea thereby defined.

Claims

1. A prefabricated concrete reinforcing element with which a first phase concrete casting (24) Is connected to another concrete casting part or other equivalent structure and possibly to its reinforcement parts (23) , said reinforcing element comprising a plurality of, preferably uniformly spaced, adhesion parts (1,3) disposed in the reinforcing element and attached to a sectional sheet cassette (10;10') in conjunction with holes (9,9') or equivalent cut-outs thereof, and said sectional sheet cassette (10;10') serving the purpose of leaving the joining adhesion parts (3) of the adhesion parts (1,3) free from the first-phase concrete casting (23) and to maintain said joining adhesion parts (3) at a given spacing, and said sectional sheet cassette (10;10') having a main wall (8) and side bends (2,4), characterized in that the sectional sheet cassette (10;10') has a central groove facing the first-phase concrete casting (24) , confined by a bottom wall (6) and by bends (5) joining this to the main wall (8) of the sectional sheet cassette (10;10'), the depth of said groove being substan¬ tially equal to or slightly smaller (h', Fig. 2) than the dimension of the cassette (10;10*) determined by the side bends (2), and that said central groove is such that it is appropriate to be used in fixing the sectional sheet cassette (10;10') to the wall (21) of the casting mould for the first-phase concrete.

2. A sectional sheet cassette for use in a prefabricated concrete reinforcing element according to claim 1, characterized in that the side bends (2) of the sectional sheet cassette (10; 10') are pos¬ itioned at an inclination under a small angle (_α) against a plane perpendicular against the plane defined by the cassette's main wall

(8) , and that said angle is preferably about 5 to 30 .

3. A sectional sheet cassette according to claim 1 or 2, charac¬ terized in that the central groove of the sectional sheet cassette (10;10') has inclined (angle ^α) side walls (5) so that the breadth (b) of the bottom part of the central groove is greater than the breadth (c) of the mouth part of said groove in the plane of the main wall (8), so that the inclined walls (5) and the main wall (8) form V-corners at an angle less than 90 with reference to each other with the purpose of advantageous pre-fixing of the joining adhesion parts (3) of the steel parts (1).

4. A sectional sheet cassette according to any one of claims 1 to 3, characterized in that the bottom parts (6) of its central groove are provided with a series of holes (7), which are preferably located halfway between the series of holes provided for the steel parts (1).

5. A sectional sheet cassette according to claim 4, characterized in that in said holes (7) is used a plug (20) of plastic or equivalent, a flange (13) on which keeps said plug (20) in conjunc- tion with the holes (7) and serves as a "fuse" for the sectional sheet cassette (10) affixed in conjunction with the mould board (21) by means of nails (14) through the hole (11) in the plug (20) when the mould board (21) is being detached from conjunction with the cured first-phase concrete (24) and with the sectional sheet cassette (10) by tearing.

6. A sectional sheet cassette according to any one of claims 1 to 5, characterized in that the sectional sheet cassette (10) has been composed of three parts, that is, of two, preferably mutually identical partial sections constituting the main plane (8), side bends (2,4) and side bends (5,16) of the central groove of the cassette (10) and of a centrally located sheet strip (15), which has been affixed, preferably by point or disk welding (25) , to the side bends (16) of said partial sections of the central groove.

7. A sectional sheet cassette according to claim 6, characterized in that the margins of said sheet strip (15) extend outside beyond the side bends (5) which are inclined (α) or perpendicular to the central strip (15), thereby forming parts (17) projecting over said bends (5) (Fig. 4).

8. A concrete reinforcing element according to any one of claims 1 to 7, characterized in that the joining adhesion parts (3) of the adhesion steel parts (1) have been so pre-stressed that they are urged against the inner surfaces of the bends (5) of the central groove and thereby pre-affix the steel parts (1,3) in place.

9. A concrete reinforcing element according to claim 8, character¬ ized in that the joining adhesion parts (3) of the adhesion steel parts (1) are bent crosswise (Fig. 8) in the manner that in the steel parts (1,3) a permanent deformation is produced so that the ends (A,A^r) of the adhesion steel parts (3) must be distanced farther apart when they are being inserted through the fixing holes (9,9',9") of the sectional sheet cassette.

10. A sectional sheet cassette according to any one of claims 1 to 9, characterized in that the bends (2,4,5,6,8,15) of the section are straight, curved, grooved, corrugated and/or said bends are provided with projections, such as nailing spikes punched out from the sheet material, for promoting the fixing to the first or second phase concrete casting.