PREFABRICATED CONCRETE REINFORCEMENT ELEMENT AND METHOD FOR MAKING REINFORCEMENT JOINTS

Abstract: A prefabricated concrete reinforcement element, which is intended for making such reinforcement joints in which a concrete cast provided with the said reinforcement element is joined together with another concrete cast portion or with any other structure and possibly with its reinforcement parts. The reinforcement element comprises several grip components (1, 3) placed in the reinforcement element as uniformly spaced. The grip components (1, 3) are attached to the base part (2), the objective of the said base part being to keep the connecting grip portions (3) of the grip components (1, 3) free from the first-stage concrete cast and to keep the said grip components (1, 3) at a certain distance from each other. The base part of reinforcement element consists of a sheet profile cassette (2, 4, 6) made of steel sheet. The cassette (2, 4, 6) is provided with openings through which the grip components (1, 3) are attached to the sheet profile cassette (2, 4, 6). The sheet profile cassette portion (2, 4, 6) functions as an additional strength element in the reinforcement joint. Moreover, a method for making reinforcement joints is suggested, in which method two concrete cast portions to be cast as different steps are joined together. In the method, the concrete reinforcement element described above is connected to the concrete cast portion to be cast first. To the side edges (6) of the concrete reinforcement element, fold planes (4) are connected, which protect the connecting grip portions (3) of their fastening components during the first concreting stage. The fold planes (4) are bent so as to be parallel to the edge folds (6) of the sheet cassette (2). Hereupon, the connecting grip portions (3) of the steel components (11) are bent to a position perpendicular to the cassette wall (2) and possibly connected to the steel components of the continued concreting. Alternatively, after the bending of the fold planes (4), separate connecting grip components are fixed to the connecting portions.

Description: Prefabricated concrete reinforcement element and method for making reinforcement joints The present invention is concerned with a prefabricated concrete reinforcement element, which is intended for making such reinforcement joints in which a concrete cast provided with the said reinforcement element is joined together with another concrete cast portion or with any other structure and possibly with its reinforcement parts, the said reinforcement element comprising several grip components placed in the rein¬ forcement element, preferably as uniformly spaced, which grip components are attached to the base part, the objective of the said base, part being to keep the connecting grip portions of the grip components free from the first-stage concrete cast and to keep the said grip components at a certain distance from each other. The invention is additionally concerned with a method for making reinforcement joints, in which method two concrete cast portions to be cast as different steps are joined together and in which method a particular prefabricated concrete reinforcement element is connected to the concrete cast portion to be cast, the grip steel components provided therein fixing the concrete reinforcement element to the cast portion to be made first and the said concrete rein¬ forcement element being provided with a component that prevents the connecting grip portions, constituting extensions ' of the grip steel components, or their coupling components from being covered in the concrete cast to be made first. In buildings, bridges, piers, and other objects of concrete construction work, so also in the prefabrication industry, in recent years, there has been an increasing tendency to use reinforcement elements manufactured in separate production plants. In the casting on site, formwork of plywood or of steel is replacing the earlier shuttering made of sawn timber, owing to its longer service life and to its better surface finish properties. In practice, at the construction site as well as in the formwork casting technique of element facto¬ ries, one of the most laborious items of work, in view of the reinforcement and of the related structures, has become the making of the reinforcement joints, which permit the joining of a reinforcement in the casting portion concerned together with another casting portion, to be made later, and with its possible rein¬ forcement components or elements. A typical example of a situation similar to that described above at a construction site is the casting of a wall: to the reinforced concrete wall portion concerned, a second wall portion must be con¬ nected by casting af erwards, but the casting of the latter wall can be performed only maybe even several days later. According to the present-day reinforcement practice, the installation and protection of the reinforcement strands permitting subsequent reinforce¬ ment joint, in order that they should not be included in the former casting, is very difficult and time-con¬ suming. As an aid, various provisional auxiliary structures are used, such as boards or equivalent, which prevent the reinforcement steel portions con¬ cerned, to be used later as joining steels, from being covered by and from adhering to the concrete casting to be performed. There are concrete reinforcement elements in use in which the concrete reinforcement components to be used later in the way described above are, regarding necessary portions, covered in an elastic plastic, styrofoa , urethane or any other, corresponding arti- ficial mix. Such an element is installed in the casting formwork with the artificial mix portion against the side towards which the casting will be continued later. After the casting has been completed, the concrete has set and the formwork been removed, it is relatively easy to dig out the concrete reinforcement components intended for joining purposes out of the rather soft artificial mix. By means of the method concerned, it is pos¬ sible to solve some of the concrete-reinforcement- technical problems of the type described above. The * said element involving portions of artificial mix is, however, inconvenient to manufacture, and the use of the element always requires steps of removal and cleansing of the artificial mix before the possibility of performing further concreting. Deficient cleansing and failure to remove any pieces of the artificial mix out of the formwork of the subsequent concreting may result in an unhomogeneous casting result and in strength-technically critical points in any concrete structures supposed to be carrying. It is an objective of the present invention to permit manufacture of concrete reinforcement elemens in a factory without extra materials superfluous for the concreting and to be removed out of the casting, by means of the shape of the element to improve the strenth properties of the cast concrete joint, and to simplify the manufacture of the reinforcement elements so that they can be produced more economically than now. The concrete reinforcement element in accord¬ ance with the invention is mainly characterized in that the said base part consists of a sheet profile cassette made of steel sheet or equivalent and that the said cassette is provided with openings through which the grip components are attached to the sheet profile cassette. Thus, the reinforcement element in accord¬ ance with the invention consists of concrete steels, or of any other steel components supposed to constitute grip portions, and of such supporting components as may remain in the concrete permanently as structural OM components improving the strength properties of the joint in the concrete work, and which components do not have to be removed before the possibility of continued concreting or of any other use taking place afterwards and which supporting components are structurally so shaped that they permit easy transportation and handling of the reinforcement elements and their easy fastening to the concreting formwork or equivalent. On the other hand, the method in accordance with the invention for making reinforcement elements is mainly characterized in that, as the said concrete reinforcement element, a sheet profile cassette is used which is provided with fold planes connected to its side edges, the said fold planes, protecting the con- necting grip portions or their fastening parts during the first concreting step, and that the said, fold planes of the sheet profile cassette are bent so as to become substantially parallel to the edge folds of the sheet profile cassette, and hereupon the connecting grip portions of the grip steel components are bent so as to become substantially perpendicular to the wall of the sheet profile cassette, and are possibly connected to the steel components of the subsequent concreting, or that, after the bending of the fold planes, separate connecting grip components are fixed to the connecting portions. It should be emphasized in this connection that an object of the present invention is also to provide concrete reinforcement elements for other types of concreting work except concreting taking place at the construction site. As examples of other objects of use should be mentioned manufacture of prefabricated concrete elements at an element factory by means of the formwork technique. Below, the invention will be described in detail with reference to some exemplifying embodiments of the invention, illustrated in the figures of the attached drawing, the invention being, however, not strictly confined to the details of the said embodi¬ ments. Figure 1 is an axonometric view of a concrete reinforcement element in accordance with the invention. Figure 2 is an axonometric view of onereinforce¬ ment steel component of the reinforcement element in accordance with the invention and of the attachement of the said component to the supporting component of the element concerned. Figure 3 is a view corresponding to that shown in Fig. 2, but with a different attachment between the., reinforcement steel component and the supporting component. Figure 4 is an axonometric view of an end construction of the reinforcement element in accordance with the invention. Figure 5 shows a reinforcement element in accordance with the. invention as placed in a concreting formwork, wherein it is, in a known way, connected to the rest of the reinforcement components in the formwork. Figure 6 shows the same as Fig. 5 does, but as viewed from above. Figure 7 shows the same as Fig. 6, but at a later point of time, after the formwork boards have been removed and the connecting components of the reinforcement element in accordance with the invention have been bent out for further connecting. Figure 8 shows the same as Fig. 7, but as a side view. Figure 9 shows the same as Fig. 7, at a later point of time, when the formwork boards of the con¬ tinued concreting are installed in position and the reinforcement steels of the continued concreting have been connected to the connecting steels of the element in accordance with the invention. Figure 10 shows the attachment of a rein¬ forcement steel component contained in the reinforce¬ ment element in accordance with the invention, to the supporting structural component. Figure 11 shows the same as Fig. 10, as viewed from above. Figure 12 shows a second reinforcement ele¬ ment in accordance with the invention as an axonometric view, the reinforcement steel components in the said element being asymmetric reinforcing steels. Figure 13 is a cross-sectional view of a reinforcement element in accordance with the invention in the concrete. Figure 14 shows the reinforcement element in accordance with the invention in the concrete as viewed from above. Figure 15 shows one possibility of fixing of the reinforcement element in accordance with the inven¬ tion to the concrete casting formwork. Figure 16 shows the same as Fig. 15, as viewed from inside the formwork. Figure 17 shows a reinforcement element in accordance with the invention in the position shown in Fig. 7, in which element the connecting steel portions have been replaced by connecting sleeves. Figure 18 shows the same as Fig. 17, as a side view. Figure 19 shows the same as Fig. 17, at a later stage, after gripping components have been con- nected to the sleeve components by known methods, the gripping components being further, in known ways, con¬ nected to the reinforcement of the further concreting portion. Figures 20, 21 and 22 show the same as Figures 17, 18 and 19, with different components for further connecting. OM The characteristic and essential components of the reinforcement element in accordance with the invention are the main components shown in Figures 1 and 12, viz. the grip steel components 1, whose number in the reinforcement element may be arbitrary and whose objective is to join the concreting and any reinforcement contained in the concreting in whose formwork the reinforcement element concerned is placed; and the steel profile cassette 2,4,6 made out of steel sheet by known methods, the said cassette, by means of its shape, supporting the grip steel components 1 and sufficiently efficiently preventing access of the first-stage concreting to the interior of the rein¬ forcement element, where the connecting grip portions 3 are located. The connecting grip portions 3 are integral extension portions of the grip steel components 1 or grip steels to be connected to same later in known methods in accordance with Figures 17 to 22. The grip steel components 1 and the connecting grip portions 3 are made, e.g., out of corrugated steel bars by bending, as has been done in Figures 1 and 12. The bent unit 1 , 3 of corrugated steel bar can be placed in the cassette 2,4,6 of the reinforce¬ ment element in the way shown in Fig. 2 as follows. The cassette 2,4,6 is made of thin steel sheet, either ordinary or zinc-coated, by known methods and shaped as a profile which is sufficiently rigid in its longi¬ tudinal direction. This rigidity is ensured by means of fold planes 4 and 6 connected to its main wall 2. Into the cassette 2,4,6, an opening 5 1 has been made by known methods, in accordance with Fig. 2, the said opening being bordered by pressing folds 5. When the fold planes 4 of the cassette 2,4,6 are spread outwards, the unit of corrugated steel bar 1,3 can be pushed through the opening 5' bordered by the pressing folds 5 far enough so that the fold planes 4 can return to their original normal position shown in Fig. 2. The connecting grip portions 3 support themselves against the fold planes 4, and the pressing fold parts 5 keep the grip steel components 1 in their position. In accordance with Fig. 3, the grip steel components 1 can be placed into the cassette 2 as follows. The unit 1 ,3 of corrugated steel bar is, regarding its connecting grip portions 3,inserted through the holes 7 made to the cassette 2,4,6. The holes 7 are placed at a distance a., in accordance with Fig. 3, from each other in the direction of the longitudinal axis of the cassette 2,4,6. By increasing the dimension a_, it is possible to increse the compression force directed at the grip steel component 1. In the case of Fig. 3, the connecting grip portions 3 support the - selves, in accordance with the above, against the fold planes 4. In accordance with Figs.1 ,2,3 and 12, the connecting grip portions 3 have been bent so that they are suppor¬ ted against the fold planes 4 and are partly overlapping other, corresponding connecting grip portions 3' included in the reinforcement element. The plane 6 determining the height of the cassette 2,4,6 has been chosen so that the free inner height h of the cassette 2,4,6 in Fig. 2 is at least twice the thickness of the connecting grip portions 3. This permits the placing of the portions 3 one on top of the other. Generally speaking, the supporting of the connecting grip portions 3 against the frame of the cassette 2,4,6 may also be performed in several other known ways, e.g., by spot welding, by punching grip barbs to the face of the cassette 2,4,6. The height of the plane 6 of the cassette 2,4,6 may also be only equal to the thickness of the connecting grip portion 3 in such cases in which the portions 3 concerned are bent in the same reinforcement element so that they are not uniform in shape as compared with each other. These embodiments, included in the scope of the f O invention, are not shown in the drawings. If the connecting grip portions 3 are supported against the cassette 2,4,6 frame, e.g., by spot welding, the fold planes 4 may be omitted out of the cassette entirely, or folded in the opposite direction, over 180 from the position shown in Fig. 2. A reinforcement element of the sort described above is placed in the concrete casting mould, e.g., in the way shown in Figures 5 and 6, whereat the fold planes 4 rest against the formwork board 8 of the concrete formwork boards 8,9 in whose direction the continued concreting will be performed afterwards. If necessary, one end or both ends of the cassette 2,4,6 may be closed in the way shown in Fig. 4 by means of a plug 10 made of steel plate or sheet, so as to prevent access of concrete into the cassette 2,4,6. The reinforcement element shown in Figures 5 and 6 is connected to the reinforcement steels 11, 12, if any, contained in the formwork 8,9. The fixing of the reinforcement element. in accordance with the inven¬ tion to the formwork board 8 may take place, e.g., in the way shown in Figures 15 and 16 by nailing, whereat holes 13 may be punched into the face of the cassette 2,4,6 in known ways, through which holes 13 the cassette 2,4,6 is fixed by means of nails 15 to the formwork board 8, a washer 14 preventing the nail 15 from passing totally through the cassette 2,4,6. After the reinforcement element in accordance with the invention has been installed in position in the way described above and connected to the other reinforcement components, if any, contained in the formwork, the concreting can be performed. According to Figures 7 and 8, the casting formwork has been removed after setting of the casting 16. After the formwork board 8 has been removed, the fold planes 4 of the cassette 2,4,6 are turned outwards in accord¬ ance with Figures 7 and 8. Hereupon the connecting OMP grip portions 3 are grasped and bent out of the interior of the cassette 2,4,6. According to Fig. 9, the form¬ work walls 17 and 18 required by the continued con¬ creting have been installed, and the connecting grip portions 3 have been connected to the other concrete reinforcement 20, 21, if any, required by the continued concreting. Hereupon, the said continued concreting is performed. Figure 14 illustrates the situation after the two completed steps of concreting. The reinforce¬ ment element with all of its essential parts is placed inside the concrete casts 16 and 22 as joined with the other steel-strength structural components 11 ,12,20,21 of the concrete casts, the cassette 2,4,6 functioning as a component increasing the strength of the working joint in the concrete. Figure 10 is a detailed view of the relative position of the pressing folds 5 and of the grip steel component 1 contained in the cassette 2,4,6. Fig. 11 shows the same as Fig. 10, as viewed from above. The pressing folds 5 may be provided with relief openings 23 at the grip steel components 1 , the said openings permitting a position of the pressing folds 5 closer to the face of the cassette 2,4,6. This is of signi- ficance when grip steel components of large dimensions are used, whereat particular attention must be directed at preventing the access of concrete into the cassette 2,4,6. In stead of the relief openings 23 shown in Fig. 11, it is possible to use seal plates made of thin steel sheet and placed inside the cassette 2,4,6 against the upper face of the cassette, the size of the said seal plates being such that they cover the opening produced by the grip steel components 1 between the pressing planes 5. Figure 13 is a sectional view of a concrete work joint and of the work joint profile produced by the pressing folds 5 contained in the cassette 2,4,6, O which profile has an effect improving the shear-strength properties of the work joint concerned. Figures 17 to 22 show a reinforcement element in accordance with the invention at different casting stages. In these elements, the grip steel components 1* are of threaded-bar material, which are, in accordance with Figures 17 and 20, supported against the cassette 2,4,6 either by means of nuts 24 or of threaded sleeve components 26. The connecting grip portions 3' also consist of threaded-bar components, which are coupled by means of sleeves 25 or 26 so as to constitute struc¬ tural parts of the reinforcement element, the said coupling not taking place until after the first casting 16 has been performed and the formwork been subsequently removed. According to the invention, a reinforcement element of simple construction suitable for manufacture in the factory has been provided, whose cassette used at the transportation and installation stages can be utilized in the performance of the concreting work itself and as a structural component in the calculations of the shear capacity of the concrete work joint. The reinforcement element in accordance with the invention may also be accomplished as provided with grip steel components 1 and connecting grip portions 3 made of other usable steel materials, except corrugated steel bars or threaded-bar material. Below, the patent claims will be given, whereat the various details of the invention may show variation within the scope of the inventional idea defined in the said claims.

Claims: WHAT IS CLAIMED IS: 1. A prefabricated concrete reinforcement element, which is intended for making such reinforce- ment joints in which a concrete cast provided with the said reinforcement element is joined together with another concrete cast portion or with any other struc¬ ture and possibly with its reinforcement parts, the said reinforcement element comprising several grip components (1, 3) placed in the reinforcement element, preferably as uniformly spaced, which grip components (1, 3) are attached to the base part (2), the objective of the said base, part being to keep the connecting grip portions (3; 24; 26) of the grip components (1, 3) free from the first-stage concrete cast and to keep the said grip components (1, 3) at a certain distance from each other, c h a r a c t e r i z e d in that the said base part consists of a sheet profile cassette (2, 4, 6) made of steel sheet or equivalent and that the said cassette is provided with openings (5'; 7) through which the grip components (1 , 3) are attached to the sheet profile cassette (2, 4, 6). 2. A concrete reinforcement element as claimed in claim 1, c h a r a c t e r i z e d in that the sheet profile cassette (2,4,6) has been arranged so as to function as an additional strength element in the reinforcement joint. 3. A concrete reinforcement element as claimed in claim 1 or 2, c h a r a c t e r i z e d in that the sheet profile cassette (2,4,6) has a cross- sectional shape substantially of a quadrangle, such as a rectangle, trapeze or equivalent, including a plane unified wall (2) , into which the said holes (5; 7) made for the grip components (1, 3) have been made, and that edge sides (6) are connected to the said plane wall (2) by means of folds, which said edge sides are extended by fold planes (4) substantially parallel to the plane wall portion, a free space remaining between the edges of the fold planes (4) . 4. A concrete reinforcement element as claimed in claim 3, c h a r a c t e r i z e d in that the said fold planes (4) function as components behind which the connecting grip portions (3) of the grip components (1), which are bent at a substantially right angle in relation to each other, are supported. 5. A concrete reinforcement element as claimed in any of claims 1 to 4, c h a r a c t e r ¬ i z e d in that a linear opening (5) has been made to the sheet wall (2) of the sheet profile cassette (2,4,6), which opening (5) is bordered by pressing folds (5')/ and that the grip components (1,3) can be attached in position to the sheet profile cassette (2,4,6) by spreading the said fold planes (4). outwards and by pushing the grip components (1 , 3) through the opening (5 1 ) bordered by the said pressing folds (5), where¬ upon the fold planes (4) return to their original normal position (Fig. 2) . 6. A concrete reinforcement element as claimed in any of claims 1 to 4, c h a r a c t e r ¬ i z e d in that individual holes (7) have been made to the wall (2) of the sheet profile cassette (2,4,6), through which holes the connecting grip portions (3) of the grip steel components (1) have been pushed to behind the fold planes (4) (Fig. 3) . 7. A concrete reinforcement element as claimed in claim 6, c h a r a c t e r i z e d in that the holes (7) , provided for each, preferably bail-shaped grip steel component (1) and placed at the peripheral areas of the wall (2) of the sheet pro¬ file cassette (2,4,6), are placed at a certain distance (a) from each other in the longitudinal direction of the sheet profile cassette (2,4,6) . 8. A concrete reinforcement element as claimed in claim 5, c h a r a c t e r i z e d in OMPI that the edges of the said pressing folds (5) are pro¬ vided with recesses or cuts (23) so that, when the grip steel components (1) are in position in the opening (5 1 ) / the edges of the pressing folds (5) come closer to each other so as to prevent leakage of the casting concrete through the opening. 9. A concrete reinforcement element as claimed in any of claims 1 to 8, c h a r a c t e r ¬ i z e d in that the grip components (1, 3) are placed in the sheet profile cassette (2,4,6) in such a way that the connecting grip portions (3) that come to lie against the plane wall (2) of the sheet profile cas¬ sette (2,4,6) become placed in the halves of the con¬ crete reinforcement element with their ends towards each other (Fig. 1) . 10. A concrete reinforcement element as claimed in any of claims 1 to 8, c h a r a c t e r ¬ i z e d in that the grip steel components (1) have been attached to the sheet profile cassette (2,4,6) by means of nuts (24), threaded sleeve components (25,26), or equivalent, which also function as fastening com¬ ponents to which the connecting grip portions (3') separate from the concrete reinforcement element have been fastened (Figures 17, 18 and 19). 11. A concrete reinforcement element as claimed in any of claims 1 to 10, c h a r a c t e r - i z e d in that the grip steel components (1) are non-continuous and only one of their ends is continued by a connecting grip portion (3, 3 1 ), which comes to lie against the face of the plane wall (2) of the sheet profile cassette (2,4,6) or close to that face behind the fold planes (4) (Fig. 12) . 12. A method for making reinforcement joints, in which method two concrete cast portions (16, 22) to be cast as different steps are joined together and in which method a particular prefabricated concrete reinforcement element is connected to the concrete cast portion (16) to be cast first, the grip steel com¬ ponents (1; 1') provided therein fixing the concrete reinforcement element to the cast portion to be made first and the said concrete reinforcement element being provided with a component (2,4,6) that prevents the connecting grip portions (3) , constituting extensions of the grip steel components (1; 1'), or their coupling components (24, 26) from being covered in the concrete cast (16) to be made first, c h a r a c t e r i z e d in that, as the said concrete reinforcement element, a sheet profile cassette is used which is provided with fold planes (4) connected to its side edges (6) , the said fold planes (4) protecting the connecting grip portions (3) or their fastening parts (24, 26) during the first concreting step, and that the said fold planes (4) of the sheet profile cassette (2,4,6) are bent so as to become substantially parallel to the edge folds (6) of the sheet profile cassette (2,4,6) , and here¬ upon the connecting grip portions (3) of the grip steel components (1) are bent so as to become substantially perpendicular to the wall (2) of the sheet profile cassette (2,4,6), and are possibly connected to the steel components (20, 21) of the subsequent concreting (22) , or that, after the bending of the fold planes (4) , separate connecting grip components (3') are fixed to the connecting portions (24, 26) (Figures 18, 19 and 22). 13. A method as claimed in claim 12, c h a r a c t e r i z e d in that the sheet profile cassette (2,4,6) is arranged as functioning as a structural component of the reinforcement joint, increasing the strength (Fig. 13). 14. A method as claimed in claim 12 or 13, c h a r a c t e r i z e d in that the sheet profile cassette (2,4,6) is fixed to the casting formwork wall (8) or equivalent of the first casting stage (16) by means of nails (15) or equivalent. OMPI 15. A method as claimed in any of claims 12, 13 or 14, c h a r a c t e r i z e d in that the holes (5"; 7) or equivalent provided for the grip com¬ ponents (1, 3) in the sheet profile cassette (2,4,6) are covered by means of particular pieces of sheet so as to prevent passage of concrete mix. OM

Inventors: AVELLAN KARI, JAERVINEN PEKKA, MAJASALO MARTTI, AVELLAN, KARI, JAERVINEN, PEKKA, MAJASALO, MARTTI
Applicants: RAKE OY
Application year: 1982
Main classification: E04C5
IPC codes: E04C5, E04G21