Joining device for precast reinforced concrete columns with a dry joint

Abstract

The joining device (100, 100) comprises a first cover (1) and a second cover (2), each of which has a plurality of through holes (3) that match up with one another in position, for the ends of the rebars of the columns (200, 200A) to pass through. The covers (1,2) are joined together by means of, at least, two transverse webs (4) and several stiffener reinforcements (5,5A), which are arranged in perpendicular to the covers (1,2). The device further comprises connecting means (202, 203, 204, 205) between the ends of the rebars (201,201A) of the columns (200,200A).

Claims

1. A joining device between two precast reinforced concrete columns, the concrete columns comprising rebars embedded therein, characterized in that it comprises a first cover and a second cover, parallel to one another, each of which has a plurality of through holes that match up with one another in position, for the ends of the rebars of the columns to pass through, and wherein the covers are joined together by means of, at least, two transverse webs and several stiffener reinforcements, which are arranged in perpendicular to the covers, the device comprising connecting means between the ends of the rebars of the columns; wherein the first cover comprises a central opening and the second cover comprises a central opening and between the central openings of the first cover and of the second cover an open central space is defined which is filled with a structural filler material.

2. Joining device according to claim 1, wherein the top cover and the bottom cover comprise at least one hole per corner and several holes situated between two corner holes, in such a way that all of the holes are at an equal distance from those adjacent to them.

3. Joining device according to claim 1, wherein the holes are slotted.

4. Joining device according to claim 1, wherein the connecting means are a coupling nut that can screw onto threaded ends of the rebars of the columns.

5. Joining device according to claim 4, comprising torque nuts configured to pretension the coupling nut.

6. Joining device according to claim 1, wherein the connecting means are a joining element formed by two tubes welded to two bars forming a double-symmetric bifurcation, in such a way that the ends of the rebars of the columns pass through the inside of the tubes and are tightened with a nut on the other side, completing the junction.

7. Joining device according to claim 1, wherein the connecting means are a male-female junction comprising a threaded rod and a coupling nut into which it is screwed.

8. Joining device according to claim 1, wherein the connecting means are welds.

9. A process for manufacturing a joining device, characterized in that it comprises the steps of: obtaining a first cover and a second cover, each of which has a plurality of through holes such that the through holes match up along a direction perpendicular to the first cover and the second cover when the first cover and the second cover face each other; welding at least two webs to the second cover by means of a continuous fillet on both sides of the webs so that they are substantially perpendicular therebetween and to the covers; welding stiffener reinforcements to the webs and to the second cover so that they are substantially perpendicular to the webs and covers; and closing the assembly by welding the first top cover to the webs and stiffener reinforcements.

10. A joining device between two precast reinforced concrete columns, the concrete columns comprising rebars embedded therein, characterized in that it comprises a first cover and a second cover, parallel to one another, each of which has a plurality of through holes that match up with one another in position, for the ends of the rebars of the columns to pass through, and wherein the covers are joined together by means of, at least, two transverse webs and several stiffener reinforcements, which are arranged in perpendicular to the covers, the device comprising connecting means between the ends of the rebars of the columns; wherein the connecting means are a joining element formed by two tubes welded to two bars forming a double-symmetric bifurcation, in such a way that the ends of the rebars of the columns pass through the inside of the tubes and are tightened with a nut on the other side, completing the junction.

11. A joining device between two precast reinforced concrete columns, the concrete columns comprising rebars embedded therein, characterized in that it comprises a first cover and a second cover, parallel to one another, each of which has a plurality of through holes that match up with one another in position, for the ends of the rebars of the columns to pass through, and wherein the covers are joined together by means of, at least, two transverse webs and several stiffener reinforcements, which are arranged in perpendicular to the covers, the device comprising connecting means between the ends of the rebars of the columns; wherein the connecting means are a male-female junction comprising a threaded rod and a coupling nut into which it is screwed.

12. A joining device between two precast reinforced concrete columns, the concrete columns comprising rebars embedded therein, characterized in that it comprises a first cover and a second cover, parallel to one another, each of which has a plurality of through holes that match up with one another in position, for the ends of the rebars of the columns to pass through, and wherein the covers are joined together by means of, at least, two transverse webs and several stiffener reinforcements, which are arranged in perpendicular to the covers, the device comprising welds between the ends of the rebars of the columns.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) What follows is a very brief description of a series of drawings which help to a better understanding of the invention, and which are expressly related to an embodiment of said invention that is presented by way of a non-limiting example of the same.

(2) FIG. 1 Shows a view of the joining device (100) object of the present invention.

(3) FIG. 2 Shows a plan detailing the maximum and minimum dimension that the joining device (100) of the present invention should have, in an embodiment with simple holes (FIG. 2a) and a second embodiment with slotted holes (FIG. 2b).

(4) FIG. 3 Shows the various steps in the process of manufacturing (i)(ii)(iii)(iv) the joining device (100) shown in FIG. 1.

(5) FIG. 4 Shows the placement of the joining device (100) of FIG. 1 upon a segment of column (200) situated below.

(6) FIG. 5 Shows the connecting means, which in this embodiment are coupling nuts (202), screwed on all the way, and the upper segment of column (200A) being supported.

(7) FIG. 6 Shows the joining device (100) between a lower segment of column (200) and an upper segment of column (200A) in use position.

(8) FIG. 7 Shows the joining device (100) wherein the connecting means incorporate a pretensioning element.

(9) FIG. 8 Shows a second embodiment of the connecting means of the joining device (100).

(10) FIG. 9 Shows a third embodiment of the connecting means of the joining device (100).

(11) FIG. 10 Shows an embodiment of the joining device (100) without a central hole.

DESCRIPTION OF A DETAILED EMBODIMENT OF THE INVENTION

(12) The attached figures show a particular exemplary embodiment of the invention. As has already been described, the joining device (100, 100) is intended to make joining together two precast reinforced concrete columns (200,200A) as simple as possible, using a minimum amount of parts, repeating them by symmetry, in such a way that they are joined to one another by means of in-shop welding, so that on site it is only necessary to place them at the specific height and join together the rebars (201,201A) of the aforementioned segments of column (200,200A) through the joining device (100, 100).

(13) The figures show an exemplary embodiment of the joining device (100, 100) that is formed by an essentially prismatic or cubic body comprising a first, top cover (1) and a second, bottom cover (2), each of which has a plurality of through holes (3) distributed around the perimeter (1,2) that match up with one another in position. In an embodiment shown in FIG. 1, the first and second covers (1,2) of the joining device (100) comprise a central opening (3A) that defines an open central space. In an embodiment shown in FIG. 10, the covers (1,2) of the joining device (100) do not have a central opening. The covers (1,2) are joined together by means of, at least, two transverse webs (4) and several inner (5) and outer (5A) stiffener reinforcements, which are arranged in perpendicular to the transverse covers (4). In the embodiment of FIG. 1, the inner space (6) defined by the webs (4) and the inner stiffeners (5) matches up with the open central space (3A) of the covers (1,2), thus defining a space that passes through the assembly.

(14) Likewise, in this particular embodiment, each through hole (3) is arranged in a quadrant delimited by the stiffener reinforcements (5,5A) and the webs (4). The joining device (100, 100) is especially intended for the purpose of connecting the rebars (201,201A) of the columns (200,200A), thus meaning that connecting means to this end will be necessary, which in this practical embodiment are a plurality of coupling nuts (202). For this purpose, the aforementioned rebars (201,201A) of the columns (200,200A) have threaded ends (threaded rods may also be welded onto the ends of the rebars).

(15) The materials used in this exemplary embodiment of the joining device (100, 100) are steels with a characteristic yield stress of at least 275 MPa. The connecting means formed by screws, nuts or threaded rods are to be made of high-strength steel with a grade of 10.9 or higher.

(16) Moreover, the distance from the outer edges at right angles to the holes (3) is normally to be comprised between 20 and 50 mm, although it may be greater. The diameter of said holes (3) is preferably comprised between 25 and 27 mm, although they may be in a greater range comprised between 13 and 35 mm.

(17) Depending on each practical embodiment, the joining device (100, 100) comprises at least one hole (3) per corner and between one and three side holes, i.e. the holes (3) situated on the sides between two corner holes. All of the holes (3) are at an equal distance from those adjacent to them aligned along the same edge.

(18) The open central space (3A) is designed to carry out the following functions: during the building phase, it makes it possible to weld the piece from the inside; it also makes it possible to fill the piece with a structural filler (concrete, mortar or resin), endowing it with a more robust core; in service, the load will mainly pass through its sides, causing the concrete of the column to bulge, thus facilitating the work done by friction; it reduces the steel consumed in making the piece.

(19) The holes (3) situated along the edge may be slotted from their theoretical position in a direction perpendicular to the edge and towards it. A feature of this slotting is that if a horizontal force is present, causing a bending moment and shear force, the shear stress will only be resisted by means of friction and butting up against the compressed rebars due to the bending moment. Furthermore, if there is a pure bending force with a homogeneous cross-section (without fissures), the neutral fiber would pass through the middle zone and one half would be compressed; in this sense, said rebars would be exploited in order to transmit the shearing stresses that could exceed the friction.

(20) The holes (3) situated at the corners have double slotting that is analogous to that of the holes (3) along the edges upon which they are located, in both directions, whose purpose it the same as that of the latter.

(21) The use of slotted holes shall not always be necessary; in some instances the friction caused by the weight gravitating upon the column shall suffice, in which cases circular holes will be valid, with or without an increased radius. It will only be necessary at those points in the building having less weight gravitating upon them, in which case collaboration with the column may be necessary.

(22) The total dimensions of the joining device (100, 100) are variable in order to adapt to a plurality of cases in terms of column (200,200A) geometry. Thus, the following table shows a non-limiting example with the illustrative maximum and minimum dimensions, which are variables of each element making up the joining device (100, 100) as detailed in FIG. 2. In cases in which segments of column (200,200A) with different cross-sections are connected, one must always consider the cross-section of the segment to be situated on top of the junction, which in general is smaller and therefore more constraining.

(23) TABLE-US-00001 Column cross-section 15 mm-thick cover Inner brace Web 300 300 mm a = 300 mm k = 115 mm l = 300 mm b = 300 mm c = 85 mm d = 107.5 mm e = 85 mm f = 107.5 mm g = 100.5 mm h = 150 mm i = 150 mm j = 100.5 mm 300 400 mm a = 400 mm k = 115 mm l = 400 mm b = 300 mm c = 135 mm d = 132.5 mm e = 85 mm f = 107.5 mm g = 150.5 mm h = 200 mm i = 150 mm j = 100.5 mm 300 500 mm a = 500 mm k = 115 mm l = 500 mm b = 300 mm c = 185 mm d = 157.5 mm e = 85 mm f = 107.5 mm g = 200.5 mm h = 250 mm i = 150 mm j = 100.5 mm 400 400 mm a = 400 mm k = 215 mm l = 500 mm b = 400 mm c = 135 mm d = 132.5 mm e = 135 mm f = 132.5 mm g = 150.5 mm h = 200 mm i = 200 mm j = 150.5 mm 400 500 mm a = 500 mm k = 215 mm l = 500 mm b = 400 mm c = 185 mm d = 157.5 mm e = 135 mm f = 132.5 mm g = 200.5 mm h = 250 mm i = 200 mm j = 150.5 mm 500 500 mm a = 500 mm k = 315 mm l = 500 mm b = 500 mm c = 185 mm d = 157.5 mm e = 185 mm f = 157.5 mm g = 200.5 mm h = 250 mm i = 250 mm j = 200.5 mm

(24) In this particular embodiment, in order to connect the column (200,200A) rebars to the joining device (100, 100), the ends of the rebars (201,201A) will be processed so that each end is threaded. To achieve this, in a particular embodiment high-strength 10.9 steel threaded rods are manually arc welded onto the end of the bars in the manner specified in standard UNE-EN ISO 17660-1:2006, through the specific arc welding method described in standard UNE-EN ISO 9692-1:2013. This has the advantage of being a transformation which may be carried out at very little cost, without requiring special equipment beyond what is needed to, for example, create the thread on the rebar itself, and with the simplest welding technique (manual arc). In another particular embodiment, threaded rebars are used straight away. In this way, the rebars (201,201A) end up face-to-face and a coupling nut (202) is used as a final joining element. Thus, said nut (202) is screwed all the way onto the lower segment of column (200), situated beneath the joining device (100, 100). The upper segment of column (200A) is then placed upon the joining device (100, 100), the rebars thus ending up face-to-face, unscrewing on one side while screwing in on the other with one single motion.

(25) The sequence of the process of manufacturing the joining device (100, 100) is shown in FIG. 3, it being manufactured in a simple fashion, by means of fillet welding the elements making it up with 5 mm-throat fillets. Thus, first the two webs (4) are welded to the second, bottom cover (2) by means of a continuous fillet on both sides of the web (4), as shown is FIG. 3, step (i). Step (ii) shows the welding of the stiffener reinforcements, specifically the outer stiffeners (5A) that are welded to the webs (4) and to the second, bottom cover (2). Lastly, step (iii) shows how the inner stiffeners (5) are welded to the second, bottom cover (2), closing the assembly with step (iv) by welding the first, top cover (1), whereby first it is placed in position in order to subsequently weld to the webs and the stiffener reinforcements (5,5A), from the outside, at least all of that which does not end up confined in the space between the webs (4) and the inner stiffeners (5). Lastly, taking advantage of the holes (3) and, in the embodiment of FIG. 1, the open central space (3A), the inner fillet of the webs (4) and of the stiffener reinforcements (5,5A) is completed. The final appearance of the joining device (100, 100) is of course the one shown in FIGS. 1 and 10.

(26) The junction may be implemented very easily on site, as shown in FIGS. 4 and 6. In the first place, the joining device (100, 100) is placed upon the end section of an existing column (200) with the ends of the rebars (201) of the existing column (200) passing through the holes (3) in the second, bottom cover (2) of the joining device (100, 100), as shown specifically in FIG. 4.

(27) Subsequently, as shown in FIG. 5, the connecting means are placed, which in this particular embodiment are nuts (202) that are screwed all the way on, ensuring that there is space to support the next column (200A).

(28) By forming the junction in this way, the end of the next column (200A) rests upon the joining device (100, 100), the ends of the rebars (201A) of the next column (200A) ending up face-to-face with the rebars (201) of the existing column (200) by passing through the holes (3) in the first, top cover (1) of the joining device (100, 100), the coupling nuts (202) then being able to join together the two rebars (201,201A), unscrewing from one and screwing onto the other. The junction is thus completed with a single motion, guaranteeing the transmission of tensile force between the rebars (201,201A) of each of the two sides, as shown in FIG. 6.

(29) As has been indicated, the means of connecting in this particular embodiment shown in FIGS. 4 to 6 are embodied as a coupling nut (202). A pretensioning effect may be achieved by following the process shown in said figures wherein first of all the joining device (100, 100) is placed on the springing point of the lower column (200). The next step consists of adding torque nuts (203) and screwing them all the way on; upon arriving at this point they are pretensioned. Once it has been pretensioned, the coupling nut (202) is added and screwed on. Then, the springing point of the top column (200A) is placed upon the device (100, 100), and the coupling nut (202) is unscrewed, thus screwing it onto the next segment of rebar. Once the connection has been made, the torque nut (203) is loosened, transmitting the stress to the top connection, and is unscrewed until it is pressed against the coupling nut (202), acting as a locknut, as shown in FIG. 7. The effect may be increased even more with another nut in the upper segment of rebar, loosening it as well and doubling the pretensioning effect.

(30) FIG. 8 shows a second embodiment of the connecting means. This second embodiment is intended not to transmit compressive stress, beyond prior preloading and pretensioning, and to avoid problems of tolerances, threads meeting, and so on. It is a joining element (204) formed by two structural steel tubes (204A) welded to two concrete-reinforcing corrugated steel bars (204B), forming a doubly-symmetrical bifurcation. The ends of the column rebars of consecutive segments (200,200A) pass through the inside of the tubes (204A) and are tightened with a nut (204C) on the other side, completing the junction. When the rebars are subjected to tensile forces, they pass the pull of the threaded end of the rebar (201) to the nut (204C), from the latter to the joining element (204), and from there to the opposite nut (204C) and opposite rebar (201A). If the rebars are compressed, they do not pass on this compression since the nut does not transmit forces, or at least not beyond the effect of loosening if it was deliberately pretensioned beforehand. Thus, this embodiment of the junction is simple: first the column is placed and afterwards the piece with the necessary connecting elements, after which the nut of the lower segment is put on, closing it, and then the upper segment is placed, the nut is placed, and the junction is thus completed.

(31) FIG. 9 shows a third embodiment of the connecting means. The form of the male-female junction consists of a threaded rod (205) and a coupling nut (205A) into which it is screwed. It has the advantage of making it possible to progressively bring them closer together, and there is an increase in tolerance that makes it easier for the top and bottom screws to meet, where it is possible for the position of the beginning of the threads to not match up and require a bit more play. Assembly is carried out by first placing the joining device (100) and the coupling nuts (205A), and then screwing the threaded rod (205) into the left over section of the nut (205A), and unscrewing the coupling nut (205A) until the end section of threaded rod meets the opposing coupling nut (205A), and both screws (205A) are screwed on and tightened, completing the junction.