Dry joint joining device between columns and beams of precast reinforced concrete

Abstract

A joining device (100) for precast reinforced concrete elements with a dry joint comprising a first group of joining reinforcements (10) arranged on a first plane and in parallel with one another, each one of said joining reinforcements (10) comprising one reinforcement (1) and two threaded ends (2). The device comprises first coupling means (30) for coupling to the columns (200) arranged between the joining reinforcements (10) and perpendicular to the first plane defined by the joining reinforcements (10) and a plurality of anchoring plates (20) arranged so as to define a closed frame inside of which the joining reinforcements (10) are arranged, and where the inner space defined by the anchoring plates (20) is filled with a structural filler material (concrete, resin, composite, etc.) (50). The anchoring plates (20) comprise a plurality of holes (21), at least one for each threaded end (2), in a position that matches up with the latter, and through which the threaded ends (2) remain accessible. The device comprises second coupling means (40) between the threaded ends (2) and the beam (300) rebars.

Claims

1. A dry joint joining device between columns and beams of precast reinforced concrete, which comprises: a first group of joining reinforcements arranged on a first plane and in parallel with one another, each one of said joining reinforcements comprising at least one reinforcement and two threaded ends; a column rebar coupling means for coupling to rebars of the columns, the column rebar coupling means being arranged between the joining reinforcements and perpendicular to the first plane defined by the joining reinforcements; a plurality of anchoring plates arranged so as to define a closed frame inside of which the joining reinforcements are arranged, and wherein an inner space defined by the anchoring plates is filled with a structural filler material, in such a way that the joining reinforcements and the column rebar coupling means are partially embedded within said structural filler material and the column rebar coupling means extend through a side of the structural filler material, said anchoring plates comprising a plurality of holes, at least one for each threaded end, in a position that matches up with said threaded ends, in such a way that through said holes the threaded ends of the joining reinforcements remain accessible; and beam rebar coupling means on the threaded ends.

2. The joining device according to claim 1, which comprises a second group of joining reinforcements arranged on a second plane and in parallel with one another, the second plane being parallel to the first plane.

3. The joining device according to claim 1, which comprises a second group of joining reinforcements arranged in a direction that is perpendicular to the first group of reinforcements.

4. The joining device according to claim 1, wherein the joining reinforcements are bifurcated, comprising two reinforcements and two threaded ends, the reinforcements being parallel to one another in such a way that they create a space for the column rebar coupling means to pass through.

5. The joining device according to claim 1, wherein the column rebar coupling means for coupling to the columns are tubes designed to house the ends of the rebars of the columns.

6. The joining device of claim 1, wherein the beam rebar coupling means are nuts configured to join the threaded ends of the reinforcements to threaded ends of the rebars of at least one beam.

7. A method of manufacturing a dry joint joining device between columns and beams of precast reinforced concrete, characterized in that it comprises the steps of: h) obtaining a joining reinforcement that comprises one reinforcement and two threaded ends, i) aligning a first group of joining reinforcements on a single first plane and in parallel with one another, j) incorporating column rebar coupling means for coupling to rebars of the columns between the joining reinforcements and perpendicular to the first plane, k) placing a plurality of anchoring plates arranged so as to define a closed frame inside of which the first group of joining reinforcements is arranged, l) inserting each threaded end of the joining reinforcements through holes in each anchoring plate, m) filling the inner space defined by the anchoring plates with a structural filler material, the column rebar coupling means extending through a side of the structural filler material, n) placing beam rebar coupling means on the threaded ends to close the holes through which the studs protrude.

8. The method of manufacturing according to claim 7, wherein the anchoring plates are welded into position by means of a fillet weld bead, welded on the inside of the corner, leaving a space of 10 mm from the edge of the corner on both sides of the corner, and with a throat of at least 5 mm.

9. The method of manufacturing according to claim 7, comprising superimposing a second group of joining reinforcements on a second plane in parallel to the first plane.

10. The method of manufacturing according to claim 7, wherein a second group of reinforcements is arranged in a direction that is perpendicular to the first group of reinforcements.

11. The method of manufacturing according to claim 7, wherein the joining reinforcements have a bifurcated shape, comprising two reinforcements and two threaded ends, the reinforcements being parallel to one another in such a way that they create a space for the column rebar coupling means to pass through.

12. The method of manufacturing according to claim 7, wherein the column rebar coupling means are tubes.

13. The method of manufacturing according to claim 7, wherein the second coupling means are nuts.

14. A use of the joining device in accordance with claim 1 with a precast column that comprises, at least, one cantilever for supporting at least one beam and a plurality of ends of the vertical rebars of the column in such a way that said joining device is placed upon the ends of the vertical rebar of the column, joining together said ends by means of first coupling means of said joining device, allowing the device to rest upon a springing point of the column, in such a way that at least one precast beam is situated upon at least one cantilever, allowing its weight to rest thereon, and is brought closer, bringing threaded ends of a beam rebar face-to-face with second coupling means of the joining device, joining them together.

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. 1Shows the manufacturing sequence of the joining device object of the invention.

(3) FIG. 2Shows a perspective view of a column for receiving precast concrete beams.

(4) FIG. 3Shows a perspective view of the column of FIG. 1 with a joining device in accordance with the present invention.

(5) FIG. 4Shows a perspective view of the column and the joining device as shown in FIG. 3, where two precast concrete beams being brought in closer may be seen.

(6) FIG. 5Shows a perspective view of the column, the beams and the joining device as shown in FIG. 4, in the final screwing position.

(7) FIG. 6Shows a plan view of phase E of the joining device object of the present invention, with simple reinforcements, including a detail of said simple reinforcement.

(8) FIG. 7Shows a plan view of phase E of the joining device object of the present invention, combining bifurcated reinforcements and simple reinforcements.

DESCRIPTION OF A DETAILED EMBODIMENT OF THE INVENTION

(9) As shown in FIG. 1, the joining device of the present invention is manufactured according to the following sequence. First of all (A), threaded studs (2) are welded onto reinforcements (1), at least one threaded stud (2) for each side of each reinforcement (1), forming a joining reinforcement (10,10). In a second stage (B), the first group of reinforcements (10) is aligned on a single plane and in parallel with one another. In a third stage (C) a second group of reinforcements oriented in perpendicular (10) is superimposed upon the first group of reinforcements (10). In this way, in each case, as many planes may be superimposed as there are beam directions, and as many rows of reinforcements as there are for each direction. In a fourth stage (D), and once the joining reinforcements (10,10) have been placed in perpendicular, a plurality of anchoring plates (20) are placed, inserting each threaded stud (2) of the joining reinforcements (10,10) through the holes (21) of each anchoring plate (20), forming an enclosure and welding the anchoring plates (20) into this position by means of a fillet weld bead, welded on the inside of the corner, leaving a space of 10 mm from the edge on both sides, and with a throat of at least 5 mm. In a fifth stage (E) a plurality of plastic or rubber tubes (30) are inserted between the spaces of the joining reinforcements (10,10) for vertical rebars of a column to pass through. Lastly, in a sixth stage (F), a plurality of nuts (40) are placed in order to close the holes (21) through which the studs (2) protrude, and a structural filler material (concrete, resin, composite, etc.) (50) is used to fill the inner space delimited by the anchoring plates (20), which make the actual formwork enclosure.

(10) Therefore, the joining device (100) thus produced comprises a plurality of joining reinforcements (10,10) arranged on two planes that are perpendicular to one another, wherein each one of said joining reinforcements (10,10) comprises, in turn, one reinforcement (1) and one threaded stud (2) welded onto each one of the ends of the reinforcement (1); and wherein said joining reinforcements (10,10) are enclosed by a plurality of anchoring plates (20) arranged around the perimeter of the assembly and with at least one plate (20) for per side comprising a plurality of holes (21) numbering at least one per stud (2) and in a position matching up with the latter, the assembly being completed with a plurality of nuts (40) numbering at least one per stud (2). Furthermore, the joining device comprises a plurality of tubes (30) arranged vertically between the joining reinforcements (10,10), the assembly being made rigid by means of concreting (50) the inner space defined by the anchoring plate (20) enclosure.

(11) In this embodiment, the tubes (30) form first coupling means for coupling with the columns (200), while in this particular embodiment the nuts (40) are second coupling means for coupling with the beams (300). Nevertheless, other coupling means that are not the aforementioned tubes and nuts may be suitable as long as they have the right form to carry out their coupling function.

(12) Moreover, the joining reinforcements (10,10) may be bifurcated reinforcements, depending on the design conditions (as in the example shown in FIG. 1), or simple ones, as in the example shown in FIG. 6, or else combining both types of reinforcements, as in FIG. 7.

(13) Thus, the joining device shown in FIG. 2 is manufactured in a very easy way, as shown in FIG. 1, with common and inexpensive components that are repeated several times through symmetry. The geometry of the junction is defined by means of the following external variables used as boundary conditions in its design.

(14) General External Variables

(15) r Cover of the reinforcement, with r10 mm
External Variables Related to the Column L.sub.x Side length in direction x, with L.sub.x200 mm. L.sub.v Side length in direction y, with L.sub.v200 mm. .sub.x Diameter of the bending rebar for bending moment Mx, with .sub.x [10,40] mm. n.sub.p,x Number of round rebars in direction x, with n.sub.p,x [3,5]. .sub.y Diameter of the bending rebar for bending moment My, with .sub.y [10,40] mm. n.sub.p,y Number of round rebars in direction y, with n.sub.y [3,5]. Type Type of column in floor plan: corner, edge, inside
External Variables Related to the Beams B.sub.x Width of the beam in the direction aligned with x, with B.sub.x . .sub.v,x Diameter of the rebar of the beam aligned with x. n.sub.v,x Number of round rebars of the beam aligned with x. f.sub.v,x Number of rows of reround bars of the beam aligned with x. sf.sub.v,x Separation between rows of round rebars of the beam aligned with x. B.sub.y Width of the beam in the direction aligned with y. .sub.v,y Diameter of the rebars in the beam aligned with direction y. n.sub.v,y Number of round rebars of the beam aligned with y. f.sub.v,y Number of rows of round rebars of the beam aligned with y. sf.sub.v,y Separation between rows of round rebars of the beam aligned with y.

(16) Based on the general variables associated with the columns and the beams, there are three basic components that are joined together to form the junction: the reinforcements (1), the plates (20), and, if applicable, the studs (2). The reinforcements (1) and the studs (2) are joined together in one component, the joining reinforcements (10,10), which may or may not be bifurcated; in the latter case the studs would not be absolutely necessary as it would be enough for the reinforcement to have both of its ends worked so as to form a thread.

(17) Design Conditions of the Continuous Joining Reinforcements (10,10), According to FIG. 6

(18) The continuous joining reinforcements are made up of either a section of reinforcement whose ends have been worked into a thread, or of a section of reinforcement with studs welded onto each of its ends, aligned in the same direction, with the threads facing outwards. The geometric constraints are the diameter and steel of the reinforcement of the incident beam, .sub.v, the side of the column in this direction, L, and the thickness of the anchoring plates, t.

(19) The continuous joining reinforcement is to have at least the same strength as the reinforcement of the incident beam. In order to ensure this, it is sufficient for the steel and diameter, , of the continuous joining reinforcement to be the same as those of the incident beam, .sub.v, where the diameter may be larger, or even smaller if the steel is stronger.

(20) The welded-on studs are to be stronger than the section of reinforcement, ensuring that breakage never takes place in the stud itself. For this purpose its metrics, Met, and the minimum nominal values of the steel, expressed based on their yield strength, f.sub.yb, and ultimate strength, f.sub.ub, are to be chosen so as to fulfill said minimum condition.

(21) The welding of the studs to the ends of the section of reinforcement is to be carried out in such a way as to ensure the total transmission of stress between the stud and the section of reinforcement, ensuring that the section of reinforcement will fail before the weld. In a particular embodiment, this is ensured by joining them together by means of butt welding.

(22) The total length of the joining reinforcement, formed by the section of reinforcement with two threaded ends or the section of reinforcement with two welded-on studs, is to be enough to exceed the side of the column in the corresponding direction, L, twice the thickness of the plates, t, and twice the length needed to screw on a nut that transmits all the stress.

(23) In the particular case of reinforcements with a nominal yield strength, f.sub.sk, of 500 MPa or less, the minimum characteristics of the studs, reinforcements, and weld beads is to be as shown in the following table:

(24) TABLE-US-00001 .sub.v Met f.sub.yb f.sub.ub [mm] [mm] [MPa] [MPa] [mm] 12 12 640 800 12 16 16 640 800 16 20 20 640 800 20 25 24 900 1000 25 32 33 640 800 32
Design Conditions of the Bifurcated Joining Reinforcements (10,10), According to FIG. 1

(25) In cases where, due to the number of round reinforcement bars of the column in any of its directions, the reinforcements intersect in space with the reinforcements of the beams, it is proposed that the reinforcements be bifurcated, leaving enough space for the vertical reinforcements to pass through.

(26) Thus, there are two geometric constraints for the bifurcation of the reinforcements. On the one hand, the diameter of the equivalent horizontal reinforcement, .sub.eq, which will condition the minimum size of the bolt, and therefore its metrics, Met, and the minimum quality of the steel, as well as the diameter of the two bifurcation reinforcements, .sub.bif and the minimum geometry of the weld bead with its length, L.sub.cor, throat a and width w, depending on its strength. On the other hand, the diameter of the vertical reinforcement, either .sub.x or .sub.y, which can cause the metrics of the stud to vary so as to adapt to the diameter of the passing reinforcement.

(27) The value of S is the separation between the reinforcements and the stud when they are welded to form the bifurcation. 1-2 mm is the norm; they are not welded while pressed together.

(28) The following table 1 shows, for the particular case of reinforcements whose nominal yield strength tension, f.sub.sk, is 500 MPa or less, several minimum conditions depending on the diameter of the equivalent horizontal reinforcement. The values of the variables expressed in the table are the minimum values, it being possible to use larger ones if so desired.

(29) The following table 1 shows the minimum geometry of the stud, Met, the characteristics of the steel of the stud, expressed in minimal nominal values of the yield strength, f.sub.yb, and ultimate strength, f.sub.ub, minimum diameter of the bifurcated reinforcements, .sub.bif, and definition of the minimum manual arc weld beads of the stud and the bifurcated reinforcement, with its length, L.sub.cor, throat a, width w and separation s.

(30) TABLE-US-00002 .sub.eq Met f.sub.yb f.sub.ub .sub.bif L.sub.cor w A s [mm] [mm] [MPa] [MPa] [mm] [mm] [mm] [mm] [mm] 12 12 640 800 10 25 7.5 3 1-2 16 16 640 800 12 30 10 4 1-2 20 20 640 800 16 40 12.5 5 1-2 25 24 900 1000 20 50 15 6 1-2 32 33 640 800 25 62.5 20 7.5 1-2

(31) Bearing in mind that the entrance .sub.eq of the table 1 will be, for a given case, .sub.eq,x in direction x, in accordance with equation (1), and .sub.eq,y in direction y, according to equation (2), both of which are shown below:
.sub.eq,x=.sub.v,x(1)
.sub.eq,y=.sub.v,y(2)

(32) Likewise, as mentioned previously, it is necessary to ensure that the vertical reinforcements can pass through, such that, once more, for a given case:
{.sub.x,.sub.y}Met+2.Math.s+2.Math.e.sub.t(3)

(33) Basically, this inequation implies that the empty space between reinforcements of the bifurcation, which is the sum of the metrics of the stud, twice the separation between stud and reinforcement, and twice the thickness of the tube, should be greater than the diameter of the corresponding vertical reinforcement.

(34) Thus, the metrics of the stud in direction x, Met.sub.x, will also be conditioned by inequation (4), and in direction y, Met.sub.y will be conditioned by inequation (5), suitable metrics being the smallest ones to simultaneously fulfill the conditions of the table which are structural conditions, and of inequations (4) and (5), which are geometric-type conditions:
Met.sub.x.sub.x2.Math.s2.Math.e.sub.t(4)
Met.sub.y.sub.y2.Math.s2.Math.e.sub.t(5)

(35) The length of the shank of the stud L.sub.c, i.e. the non-threaded portion of the total length, is to be at least equal to the sum of the thickness of the anchoring plate t and the length of the weld bead L.sub.cor, as expressed in the following inequation (6):
L.sub.cL.sub.cor+t(6)

(36) The length of the threaded portion L.sub.ros is to be greater than or equal to twice the height of the standard nut corresponding to high-strength screws with the metrics of the stud, such that it will be greater than or equal to the length expressed in Table 2.

(37) Table 2 shows Minimum threaded lengths, L.sub.ros, based on the metrics of the stud.

(38) TABLE-US-00003 Met L.sub.ros [mm] [mm] 10 16 12 20 16 26 20 32 22 36 24 38 27 44 30 48 33 52 36 58

(39) The length of the bifurcated reinforcements L.sub.bif in each of the directions x and y, will depend on the side of the corresponding column, L.sub.x or L.sub.y, in a given case, of the cover, r, of the concrete, of the lengths of the weld bead L.sub.c obtained according to the table 1 in the corresponding direction, as well as the thickness of the chosen tube e.sub.t.
L.sub.bif,x=L.sub.x2.Math.r+2.Math.L.sub.cor+2.Math.e.sub.t(7)
L.sub.bif,y=L.sub.y2.Math.r+2.Math.L.sub.cor+2.Math.e.sub.t(8)
Design Conditions of the Anchoring Plates (20).

(40) In all cases, the anchoring plates are to be made of steel with a nominal yield strength of at least 275 MPa or higher. The anchoring plates in direction x are to have a thickness t.sub.x, a length L.sub.ca,x and a border h.sub.x. They are to have n.sub.v,x circular holes with a diameter d.sub.0,x passing through the entire thickness, situated in one single row. The distances between rows of one single side are to be equal to the separations of the incident reinforcements, sf.sub.v,x and sf.sub.v,y, according to the given side, and will have as many rows as there are rows of reinforcements, f.sub.v,x and f.sub.v,y, according to the given side, with distances from the end rows to the edges of the border e.sub.l,x and e.sub.r,x and distances from the end holes of each row to the edges of the long side e.sub.t,x and e.sub.b,X, keeping the equal distance between the holes of each single row equal to p.sub.x. The minimum dimensions thus defined will maintain their relationships to one another and with the rest of elements of the junction expressed in the following equations (9) and (15).

(41) $\begin{array}{cc}{t}_{x}0,4.Math.{}_{v,y}& \left(9\right)\\ h_x{e}_{t,x}+e_{i,y}+\frac{{}_{\mathrm{bif},x}}{2}+\frac{{}_{\mathrm{bif},y}}{2}& \left(10\right)\\ L_{\mathrm{ca},x}=L_{\mathrm{bif},x}+t_y& \left(11\right)\\ d_{0,x}={}_{v,y}+2.Math.\mathrm{mm}& \left(12\right)\\ p_x=\frac{L_{\mathrm{ca},x}-e_{i,x}-e_{d,x}}{n_{v,y}-1}& \left(13\right)\\ e_{d,x}=e_{i,x}+t_y& \left(14\right)\\ e_{b,x}=h_x-e_{i,x}& \left(15\right)\end{array}$

(42) In turn, the minimum values of e.sub.i,x (distance from the left edge) and e.sub.t,x (distance to the top edge) may be obtained from Table 3 below:

(43) TABLE-US-00004 Met e.sub.i, x e.sub.t, x [mm] [mm] [mm] 10 15 15 12 20 20 16 25 25 20 30 30 22 30 30 24 35 35 27 40 40 30 40 40 33 45 45 36 50 50

(44) In direction y the same equations (9) to (15) would be applied, along with table 3 above, but substituting x with y and vice versa.

(45) As an example, a joining device (100) is presented which is made based on the specifications made herein above for the case of a 3030 cm column, with all of the reinforcements having =25 mm and 3 round bars in each direction.

(46) In order to place the joining device (100) object of the invention, a section of precast column (200) such as the one presented in FIG. 2 is initially available. It is a classic column design, with two cantilevers (201,202) to support the beams (300) and the ends of the reinforcements (203) of the vertical reinforcement of the column.

(47) In the first place, the joining device (100) is placed upon the ends (203) of the vertical rebars of the column (200) making said ends (203) pass through the hollow space of the tubes (30), allowing the device (100) to rest upon the springing point of the column (200), as shown in FIG. 3.

(48) Subsequently, the precast beams (300) are placed upon the cantilevers (201,202), letting the weight rest thereon, and they are brought in closer, leaving a space (d) in which to operate, as shown in FIG. 4.

(49) Lastly, the beams (300) are brought closer to the joining device (100), bringing the threaded ends (301) of the beams (300) face-to-face with the nuts (40) of the joining device (100), unscrewing on one side in order to screw in on the other, completing the joining process as shown in FIG. 5. If the column (200) is on an edge or corner, a commercial flange nut with a skirt and a washer is left on the other side to distribute the load such that the reinforcement is anchored, although the enclosure formed by the stud and the bifurcated reinforcement surrounding the vertical reinforcement and the adherence between the reinforcement and the structural filler material (concrete, resin, composite, etc.) will also play a part.